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C-R-Newsletter #36 December 31, 2005
Editor's
Note: We wrap up CRN's third year, appropriately, with monthly
newsletter #36. Here's wishing all our readers a prosperous and joyous
2006!
CRN
Goes to Yale
New
President at Foresight
CRN
Task Force Progress
Bragging
About Blogging
A
Global Surge Protector?
Inside
CRN, Parts 1-5
Milestones & Moving
Forward
Feature
Essay: Simple Nanofactories vs. Floods of Products
Every month this newsletter gets you
up to date on recent events, but to follow the latest happenings on a daily
basis, be sure to check our Responsible
Nanotechnology weblog.
=========
CRN
Goes to Yale
On Wednesday, December 7, CRN Executive Director Mike Treder gave a talk on "Transforming
Society: Ethical Issues in the Nanotech Revolution," at Yale University's
Institute for Social and Policy Studies. The presentation was addressed to
Yale's Technology
and Ethics Working Research Group, an interdisciplinary affiliation
of faculty, students, and community members.
A unique feature
of this opportunity was its length. The format allows for about 90 minutes
of lecture and discussion, followed by a brief break for dinner (delivered
to the meeting), and then more informal discussion. With almost three
hours to approach a topic, the presenter and group are able to explore
it in some depth. Still, at the end several people commented that we had
barely scratched the surface of the many serious issues surrounding advanced
nanotechnology.
New President at Foresight
The Foresight Nanotech Institute has a new
president. On December 9, Scott Mize stepped down after one year in
the position, and Marc Lurie was appointed to replace him. Prior to joining
Foresight, Lurie founded and as CEO helmed @hand, a software and services
company delivering mission-critical mobile solutions to large enterprises.
CRN Task Force Progress
Work is proceeding smoothly for the CRN
Global Task Force on Implications and Policy, a diverse group of world-class
experts brought together to develop comprehensive recommendations for the
safe and responsible use of molecular manufacturing.
Currently, we are completing first drafts on a series of essays that each
identifies a specific concern of a task force member about advanced nanotechnology.
Almost 20 essays have been written so far. When these are published in anthology
form early next year, we will ask for feedback on our ideas, as well as public
input on additional concerns.
Bragging About Blogging
Technorati is
the equivalent of Google for the blogosphere. Currently tracking 23.4 million
sites and 1.8 billion links, Technorati ranks weblogs by what they call 'authority',
based on the number of confirmed links from other blog sites.
According to them,
CRN's Responsible
Nanotechnology blog has more authority than 99.9% of all the others
out there. Of course, there are a lot of blogs, and many of them are
highly esoteric. But it's nice to know that so many other bloggers have
seen the value of referring their readers to our work.
A Global Surge Protector?
Concentration of power is the topic of Mike Treder's most recent Future
Brief essay...
Molecular manufacturing represents power: political power, military power, and economic power. When this power becomes available, will a "global surge protector" be needed? If so, how might that be devised and implemented?
Who controls that power and how widely -- how democratically -- it is distributed will make all the difference when nanotechnology is fully developed. Decisions we make before that time will determine whether our world becomes safer or more dangerous; more just or less just; more free or more oppressive.
Chances are you have a surge protector in your home to shield electronic devices from unexpected power surges. Someday soon, we may need protection from unprecedented surges in global political power.
Read the full
essay here.
Inside CRN, Parts 1-5
In December, we published a five-part
series on our blog that gave a look “inside” CRN. The series
of short articles reviewed the process CRN follows in choosing how and what
to describe as the likely results of our research into molecular manufacturing.
Commenting on the series, Jamais Cascio of WorldChanging.com said:
CRN looks primarily at the implications of what they term "middle period" nanotech, such as nanofactories -- much more sophisticated than nanomaterials, but not the fantastic nanoassemblers of science fiction. I strongly encourage our readers to check out the recently-concluded "Inside CRN" series at the Center for Responsible Nanotechnology blog. The five posts cover CRN's mission and goals, and explain how their focus differs from other nanotech resources. It's a great introduction to an extremely valuable organization.
Milestones & Moving
Forward
As we commemorate our 3rd anniversary this month, we are proud of what we've
accomplished so far, but mindful that greater challenges await us in 2006.
This is important work that few others are doing. To keep moving forward,
we will need to grow fast.
A new
page on our website lists some of the significant milestones from CRN's
first three years. That page also outlines our current priorities—including
research, outreach, and development—and suggests several ways in which
you can help advance this work.
Feature Essay: Simple Nanofactories vs. Floods
of Products
Chris Phoenix, Director of Research, Center for Responsible Nanotechnology
In last
month's essay, I explained why even the earliest meter-scale nanofactories
will necessarily have a high throughput, manufacturing their own mass in
just a few hours. I also explained how a nanofactory can fasten together
tiny functional blocks—nanoblocks—to make a meter-scale product.
The next question is what range of products an early nanofactory would be
able to build.
For several reasons, it is important to know the range and functionality of
the products that the nanofactory will produce, and how quickly new products
can be developed. Knowing these factors will help to estimate the economic
value of the nanofactory, as well as its impacts and implications. The larger
the projected value, the more likely it is to be built sooner; the more powerful
an early nanofactory is and the faster new products appear, the more disruptive
it can be.
Because a large nanofactory can be built only by another nanofactory, even
the earliest nanofactories will be able to build other nanofactories. This
means that the working parts of the nanofactory will be available as components
for other product designs. From this reasoning, we can begin to map the lower
bound of nanofactory product capabilities.
This essay is a demonstration of how CRN's thinking and research continue
to evolve. In 2003, I published a peer-reviewed paper called "Design
of a Primitive Nanofactory" in which I described the simplest nanofactory
I could think of. That nanofactory had to do several basic functions, such
as transporting components of various sizes, that implied the need for motors
and mechanical components also in a variety of sizes, as well as several
other functions. However, not long after that paper was published, an even
simpler approach was proposed by John Burch and Eric Drexler. Their
approach can build large products without ever having to handle large
components; small blocks are attached rapidly, directly to the product.
The planar assembly approach to building products is more flexible than the
convergent assembly approach, and can use a much more compact nanofactory.
Instead of having to transport and join blocks of various sizes within the
nanofactory, it only needs to transport tiny blocks from their point of fabrication
to the area of the product under construction. (The Burch/Drexler nanofactory
does somewhat more than this, but their version could be simplified.) This
means that the existence of a nanofactory does not, as I formerly thought,
imply the existence of centimeter-scale machinery. A planar nanofactory can
probably be scaled to many square centimeters without containing any moving
parts larger than a micron.
Large moving parts need to slide and rotate, but small moving parts can be
built to flex instead. It is theoretically possible that the simplest nanofactory
may not need much in the way of bearings. Large bearings could be simulated
by suspending the moving surface with numerous small load-bearing rollers
or "walkers" that could provide both low-friction motion and power. This
might actually be better than a full-contact surface in some ways; failure
of one load-bearing element would not compromise the bearing's operation.
Another important question is what kind of computers the nanofactory will
be able to build. Unlike my "primitive nanofactory," a simple planar-assembly
nanofactory may not actually need embedded general-purpose computers (CPU's).
It might have few enough different components that the instructions for building
all the components could be fed in several times over during construction,
so that information storage and processing within the nanofactory might be
minimal. But even a planar-assembly nanofactory, as currently conceived, would
probably have to incorporate large amounts of digital logic (computer-like
circuitry) to process the blueprint file and direct the operations of the
nanofactory fabricators. This implies that the nanofactory's products could
contain large numbers of computers. However, the designs for the computers
will not necessarily exist before they are needed for the products.
Any nanofactory will have to perform mechanical motions, and will need a power
source for those motions. However, that power source may not be suitable for
all products. For example, an early nanofactory might use chemicals for power.
It seems more likely to me that it would use electricity, because electric
motors are simpler than most chemical processing systems, since chemical systems
need to deliver chemicals and remove waste products, while electrical systems
only need wires. In that case, products could be electrically powered; it
should not be difficult to gang together many nanoscale motors to produce
power even for large products.
The ability to fasten nanoscale blocks to selected locations on a growing
product implies the ability to build programmable structures at a variety
of scales. At the current level of analysis, the existence of a large nanofactory
implies the ability to build other large structures. Because the nanofactory
would not have to be extremely strong, the products might also not be extremely
strong. Further analysis must wait for more information about the design of
the nanofactory.
Sensing is an important part of the functionality of many products. An early
nanofactory might not need many different kinds of sensing, because its operations
would all be planned and commands delivered from outside. One of the benefits
of mechanosynthesis of
highly cross-linked covalent solids is that any correctly built structure
will have a very precise and predictable shape, as well as other properties.
Sensing would be needed only for the detection of errors in error-prone operations.
It might be as simple as contact switches that cause operations to be retried
if something is not in the right place. Other types of sensors might have
to be invented for the products they will be used in.
Nanofactories will not need any special appearance, but many products will
need to have useful user interfaces or attractive appearances. This would
require additional R&D beyond what is necessary
for the nanofactory.
The planar assembly approach is a major simplification relative to all previous
nanofactory approaches. It may even be possible to build wet-chemistry nanofactory-like
systems, as described in my NIAC
report that was completed in spring 2005, and bootstrap incrementally
from them to high-performance nanofactories. Because of this, it seems less
certain that the first large nanofactory will be followed immediately by
a flood of products.
A flood of products still could occur if the additional product functionality
were pre-designed. Although pre-designed systems will inevitably have bugs
that will have to be fixed, rapid prototyping will help to reduce turnaround
time for troubleshooting, and using combinations of well-characterized small
units should reduce the need for major redesign. For example, given a well-characterized
digital logic, it should not be more difficult to build a CPU than to write
a software program of equivalent complexity—except that, traditionally,
CPU's have required months to build each version of the hardware in the semiconductor
fab.
An incremental approach to developing molecular manufacturing might start
with a wet-chemical self-assembly system, then perhaps build several versions
of mechanosynthetic systems for increasingly higher performance, then start
to develop products. Such an incremental approach could require many years
before the first general-purpose product design system was available. On the
other hand, a targeted development program probably would aim at a dry mechanosynthetic
system right from the start, perhaps bypassing some of the wet stages. It
would also pre-design product capabilities that were not needed for the basic
nanofactory. By planning from the start to take advantage of the capabilities
of advanced nanofactories, a targeted approach could develop a general-purpose
product design capability relatively early, which then would lead to a potentially
disruptive flood of products.
* * * * * * * * * * * * * * * *
FUNDRAISING ALERT!
Recent developments in efforts to roadmap
the technical steps toward molecular manufacturing make the work of
CRN more important than ever. It is critical that we examine the global
implications of this rapidly emerging technology, and begin creating wise
and effective solutions. That’s why we have formed the CRN
Task Force.
But it won't be easy. We need to grow, and rapidly, to meet the expanding
challenge.
Your tax-deductible donation
to CRN will help us to achieve that growth. We rely largely on individual
donations and small grants for our survival. This is important work and
we welcome your participation.
Thank you!
* * * * * * * * * * * * * * * *
C-R-Newsletter #35 November 30, 2005
On December 30,
2004, we
wrote in our blog: "Things are really starting to heat up around
nanotechnology. It looks to us as if 2005 is going to be a huge year
for tiny tech."
That prediction was right on the mark. The last 11 months have seen tremendous
progress in nanoscience and technology. In this Special Issue of
the C-R-Newsletter, we'll highlight a few of the remarkable developments that
have made 2005 the Year of Nano.
Two
Major MM Papers from Chris Phoenix
CRN
Inspires Research on DNA
Nanoscale
Engineering at Northwestern
Building
Molecular Machines at Rice
Pitt
Goes Top-Down & Bottom-Up
Nanotech
Roadmap Update
CRN
Task Force Progress
Milestones & Moving
Forward
Feature
Essay: Notes on Nanofactories
Every month this newsletter gets you up to date on recent events, but to follow the latest happenings on a daily basis, be sure to check our Responsible Nanotechnology weblog.
=========
Two
Major MM Papers from Chris Phoenix
Earlier this year, CRN's Director of Research Chris Phoenix produced two important
papers. "Developing
Molecular Manufacturing" was published in March, and then in May, Chris
released the findings of a study he performed for NASA's Institute for Advanced
Concepts
The first paper proposes that the development of molecular manufacturing can
be an incremental process from today's capabilities, and may not be as distant
as many believe. Three stages for the development of molecular manufacturing,
each with specific milestones, are identified: 1) computer-controlled fabrication
of precise molecular structures; 2) exponential growth of the manufacturing
base using nanoscale tools to build more tools; 3) integrating nanoscale products
into large structures, leading to desktop "nanofactories" that could build
advanced products.
The second work, titled "Molecular
Manufacturing: What, Why and How," provides a new analysis of existing
technological capabilities, including proposed steps from today's nanotech
to advanced molecular machine systems. Chris describes two approaches for
building the initial basic tools with current technology. Other sections
outline incremental improvement from those early tools toward the first
integrated nanofactory, and analyze a scalable architecture for a more advanced
nanofactory. Product performance and likely applications are discussed,
as well as incentives for corporate or government investment in the technology.
Finally, considerations and recommendations for a targeted development program
are presented.
CRN Inspires Research on DNA
Inspired by one of CRN's Thirty
Essential Studies — Study
#10, "What will be required to develop nucleic acid manufacturing
and products?" — Frank Boehm wrote "An
Investigation of Nucleic Acid/DNA-Based Manufacturing." In this
26-page paper with 242 references, published online in April at the
Wise-Nano.org website, Boehm describes many different kinds of tools
in the DNA device toolbox, and shows how rapidly development is occurring
in this field.
Nanoscale Engineering at Northwestern
One path to molecular manufacturing would use a traditional machining approach
to build small systems that can perform increasingly precise operations, similar
to what was originally proposed by Richard
Feynman. Current university research may be significantly improving
the chances of success for this approach.
In September, we
reported that researchers at Northwestern had designed a tiny sensitive
system for applying and sensing force, welded samples to the device using
a new and very powerful nanoscale manufacturing system, then put the device
in a tunneling electron microscope (TEM), and watched the tube while they
pulled it apart.
Although nothing in this work is atomically precise (with the possible exception
of the TEM microscopy), it is getting close. The ability to integrate MEMS,
nano-manipulation, FIB, and SEM in a single manufacturing system opens a vast
new array of experiments and adds a powerful new part to the nanotech
toolbox.
Building Molecular Machines at Rice
Is anyone doing actual lab work on molecular manufacturing? We're
often asked that question, and now we have a positive answer: A research group
at Rice University that produced the nanocar.
Their reported goal is to "build tiny trucks that could carry atoms and molecules
around in miniature factories."
Dr.
James Tour, one of the two lead researchers at Rice, says, "The synthesis
and testing of nanocars and other molecular machines is providing critical
insight in our investigations of bottom-up molecular manufacturing. We'd
eventually like to move objects and do work in a controlled fashion on the
molecular scale, and these vehicles are great test beds for that. They're
helping us learn the ground rules."
Pitt Goes Top-Down & Bottom-Up
In a span of two weeks in late October, we read a remarkable pair of reports
about important nanotechnology work taking place at the University of Pittsburgh's
Institute of NanoScience and Engineering.
The first
account told of Pitt scientists using an advanced nanofabrication system
to create the world's smallest chess pieces, approximately 400 nanometers
wide. Although this new top-down technology is not quite atomically precise,
it does use an electron beam focused to less than two nanometers, allowing
researchers to create nanometer-scale structures.
In the second
instance, we learned more about the impressive progress being made by
Christian Schafmeister, assistant professor of chemistry at the University
of Pittsburgh. His experimental work—designing modular molecules that
link together in predictable ways with pairs of stiff bonds—will enable,
for the first time, the quick manufacture of sturdy, predictable nanostructures.
Because the molecules are large enough to have interesting functions and
rigid, designed shapes, they hold great promise as nanoscale parts for future
atomically precise nanoscale machines.
Nanotech Roadmap Update
Last summer, the Foresight Nanotech Institute and the Battelle research
organization announced that they would work together to produce a Technology
Roadmap for Productive Nanosystems. This effort is being funded in part by
the Waitt Family Foundation, as well as by corporate supporters including
Sun Microsystems. The published Roadmap
Background states a clear intention to close the "implementation gap" separating
today's nanostructures from the "complex productive nanosystems of the future."
They say that biopolymers (DNA, protein) can provide a basis for the design
and fabrication of atomically precise, self-assembling composite structures—forming
molecular components that bind and organize diverse nanostructures (nanotubes,
macromolecules) to form molecular machine systems. Further steps are expected
to show the way from the production of 1-dimensional polymers to 2- and 3-dimensional
covalent structures, from self-assembly to simpler, mechanical construction
methods, and from microscopic systems to desktop-scale factories.
Ultimately, these advanced productive nanosystems (molecular manufacturing
systems) should enable the fabrication of large, complex products cleanly,
efficiently, and at low cost. According to Eric
Drexler, one of the lead researchers on the Roadmap project, nanofactory
products could include:
|
Desktop computers with a billion processors |
|
|
Inexpensive, efficient solar energy systems |
|
|
Medical devices able to destroy pathogens and repair tissues |
|
|
Materials 100 times stronger than steel |
|
|
Superior military systems |
|
|
Additional molecular manufacturing systems |
CRN Task Force Progress
The July announcement of an initiative to create a Technology Roadmap for
Productive Nanosystems (see above) motivated CRN to organize a parallel process
of study and action: the CRN Global Task Force on Implications and Policy.
Bringing together a diverse group of world-class experts from multiple disciplines,
CRN is leading an historic, collaborative effort to develop comprehensive
recommendations for the safe and responsible use of molecular manufacturing.
We now have more than 50
participants from six different countries on the CRN Task Force. Currently,
the group is working on a series of short essays to identify specific concerns
that must be addressed. When these are published in anthology form early
next year, we will ask for feedback on our ideas, as well as public input
on additional concerns.
Milestones & Moving
Forward
As CRN approaches our 3rd anniversary, we are proud of what we've accomplished
so far, but mindful that greater challenges await us in 2006. This is important
work that few others are doing. To keep moving forward, we will need to grow
fast.
A new
page on our website lists some of the significant milestones from CRN's
first three years. That page also outlines our current priorities—including
research, outreach, and development—and suggests several ways in which
you can help advance this work.
Feature Essay: Notes on Nanofactories
Chris Phoenix, Director of Research, Center for Responsible Nanotechnology
This month's science essay is prompted by several questions about nanofactories
that I've received over the past few months. I'll discuss the way in which
nanofactories combine nanoscale components into large integrated products;
the reason why a nanofactory will probably take about an hour to make its
weight in product; and how to cool a nanofactory effectively at such high
production rates.
In current nanofactory designs, sub-micron components are made at individual
workstations and then combined into a product. This requires some engineering
above and beyond what would be needed to build a single workstation. Tom Craver,
on our
blog, suggested that there might be a transitional step, in which workstations
are arranged in a two-dimensional sheet and make a thin sheet of product.
The sheet of manufacturing systems would not have to be flat; it could be
V-folded, and perhaps a solid product could be pushed out of a V-folded
arrangement of sheets. With a narrow folding angle, the product might be
extruded at several times the mechanosynthetic deposition rate.
Although the V-fold idea is clever, I think it's not necessary. Once you can
build mechanosynthetic systems that can build sheets of product, you're most
of the way to a 3D nanofactory. For a simple design, each workstation produces
a sub-micron "nanoblock" of product (each dimension being the thickness of
the product sheet) rather than a connected sheet of product. Then you have
the workstations pass the blocks "hand over hand" to the edge of the workstation
sheet. In a primitive nanofactory design, much of the operational complexity
would be included in the incoming control information rather than the nanofactory's
hardware. This implies that each workstation would have a general-purpose
robot arm or other manipulator capable of passing blocks to the next workstation.
After the blocks get to the edge of the sheet, they are added to the product.
Instead of the product being built incrementally at the surface of V-folded
sheets, the sheets are stacked fully parallel, just like a ream of paper,
and the product is built at the edge of the ream.
Three things will limit the product ‘extrusion’ speed:
- The block delivery speed. This would be about 1 meter per second, a typical speed for mechanisms at all scales. This is not a significant limitation.
- The speed of fastening a block in place. Even a 100-nanometer block has plenty of room for nanoscale mechanical fasteners that can basically just snap together as fast as the blocks can be placed. Fasteners that work by molecular reactions could also be fast.
- The width (or depth, depending on your point of view) of the sheet: how many workstations are supplying blocks to each workstation-width edge-of-sheet. The width of the sheet stack is limited by the ability to circulate cooling fluid, but it turns out that even micron-wide channels can circulate fluid for several centimeters at moderate pressure. So you can stack the sheets quite close together, making a centimeter-thick slab. With 100-nanometer workstations, that will have several thousand workstations supplying each 100-nanometer-square edge-of-stack area. If a workstation takes an hour to make a 100-nanometer block, then you're depositing several millimeters per hour. That's if you build the product solid; if you provide a way to shuffle blocks around at the product-deposition face, you can include voids in the product, and 'extrude' much faster; perhaps a mm per second.
Tom pointed out
that a nanofactory that built products by block deposition would require
extra engineering in several areas, such as block handling mechanisms,
block fasteners, and software to control it all. All this is true, but
it is the type of problem we have already learned to solve. In some ways,
working with nanoblocks will be easier than working with today's industrial
robots; surface forces will be very convenient, and gravity will be too
weak to cause problems.
On the same blog post, Jamais Cascio asked why
I keep saying that a nanofactory will take about an hour to make its weight
of product. The answer is simple: If the underlying technology is much slower
than that, it won't be able to build a kilogram-scale nanofactory in any reasonable
time. And although advanced nanofactories might be somewhat faster, a one-hour
nanofactory would be revolutionary enough.
A one-kilogram one-hour nanofactory could, if supplied with enough feedstock
and energy, make thousands of tons of nanofactories or products in a single
day. It doesn't much matter if nanofactories are faster than one hour (3600
seconds). Numbers a lot faster than that start to sound implausible. Some
bacteria can reproduce in 15 minutes (900 seconds). Scaling laws suggest that
a 100-nm scanning probe microscope can build its mass in 100 seconds. (The
non-manufacturing overhead of a nanofactory—walls, computers, and so
on—would probably weigh less than the manufacturing systems, imposing
a significant but not extreme delay on duplicating the whole factory.) More
advanced molecule-processing systems could, in theory, process their mass
even more quickly, but with reduced flexibility.
On the slower side, the first nanofactory can't very well take much longer
than an hour to make its mass, because if it did, it would be obsoleted before
it could be built. It goes like this: A nanofactory can only be built by a
smaller nanofactory. The smallest nanofactory will have to be built by very
difficult lab work. So you'll be starting from maybe a 100-nm manufacturing
system (10-15 grams) and doubling sixty times to build a 103 gram
nanofactory. Each doubling takes twice the make-your-own-mass time. So a one-hour
nanofactory would take 120 hours, or five days. A one-day nanofactory would
take 120 days, or four months. If you could double the speed of your 24-hour
process in two months (which gives you sixty day-long "compile times" to build
increasingly better hardware using the hardware you have), then the half-day
nanofactory would be ready before the one-day nanofactory would.
Tom Craver pointed out that if the smaller nanofactory can be incorporated
into the larger nanofactory that it's building, then doubling the nanofactory
mass would take only half as long. So, a one-day nanofactory might take only
two months, and a one-hour nanofactory less than three days. Tom also pointed
out that if a one-day tiny-nanofactory is developed at some point, and its
size is slowly increased, then when the technology for a one-hour nanofactory
is developed, a medium-sized one-hour nanofactory could be built directly
by the largest existing one-day nanofactory, saving part of the growing time.
In my "primitive
nanofactory" paper, which used a somewhat inefficient physical architecture
in which the fabricators were a fraction of the total mass, I computed that
a nanofactory on that plan could build its own mass in a few hours. This
was using the Merkle pressure-controlled fabricator, (see "Casing
an Assembler"), with a single order of magnitude speedup to go from
pressure to direct drive.
In summary, the one-hour estimate for nanofactory productivity is probably
within an order of magnitude of being right.
The question about cooling a nanofactory was asked at a talk I gave a few
weeks ago, and I don't remember who asked it. To build a kilogram per hour
of diamond requires rearranging on the order of 1026 covalent bonds
in an hour. The bond energy of carbon is approximately 350 kJ/mol, or 60 MJ/kg.
Spread over an hour, that much energy would release 16 kilowatts, about as
much as a plug-in electric heater.
Of course, you don't want a nanofactory to glow red-hot. And the built-in
computers that control the nanofactory will also generate quite a bit of heat--perhaps
even more than the covalent reactions themselves. So, fluid cooling looks
like a good idea. It turns out that, although the inner features of a nanofactory
will be very small—on the order of one micron—cooling fluid can
be sent for several centimeters down a one-micron channel with only a modest
pressure drop. This means that the physical architecture of the nanofactory
will not need to be adjusted to accommodate variable-sized tree-structured
cooling pipes.
In the years I have spent thinking about nanofactory design, I have not encountered
any problem that could not be addressed with standard engineering. Of course,
engineering in a new domain will present substantial challenges and require
a lot of work. However, it is not safe to assume that some unexpected problem
will arise to delay nanofactory design and development. As work on enabling
technologies progresses, it is becoming increasingly apparent that nanofactories
can be addressed as an integration problem rather than a fundamental research
problem. Although their capabilities seem futuristic, their technology may
be available before most people expect it.
C-R-Newsletter #34 October
16, 2005
Major
Advances in Nanoscale Engineering
New
Technical Information Freely Available
CRN
Task Force Progress Report
Dark
Visions of a Fantastic Future
CRN
Interviewed re Military Nanotechnology
CRN
Gets Podcasted
We're
on CNET’s Blog 100 List
CRN
Goes to Chicago, Again
CRN
Goes to San Francisco
CRN
Goes to Michigan
CRN
Goes to Seattle
Feature
Essay: Early Applications of Molecular Manufacturing
=========
What
a whirlwind! We'll fill you in on recent events here, but to keep up with
the latest happenings on a daily basis, be sure to check our Responsible
Nanotechnology weblog.
Also, please notice the FUNDRAISING
ALERT at the end of this newsletter.
Major Advances in Nanoscale Engineering
There are several possible
paths to molecular manufacturing. Eric Drexler favors starting with
biopolymer-based systems and improving them incrementally. Robert Freitas
and Ralph Merkle propose using scanning probe microscopes to do direct mechanosynthesis
of diamondoid systems. Another researcher, Josh Hall, favors a third path:
using a more traditional machining approach to build small systems that
can perform increasingly precise operations, similar to what was originally
proposed by Richard
Feynman.
Exciting
work at Northwestern University could significantly improve the chances
of the third approach succeeding. Researchers there recently designed a
tiny sensitive system for applying and sensing force, had samples welded
to the device using a new and very powerful nanoscale manufacturing system,
then put the device in a tunneling electron microscope (TEM) and watched
the tube while they pulled it apart.
Although nothing in this work is atomically precise (with the possible exception
of the TEM microscopy), it's getting close. The ability to integrate MEMS,
nano-manipulation, FIB, and SEM in a single manufacturing system opens a vast
new array of experiments and adds a powerful new part to the nanotech
toolbox.
New Technical Information Freely Available
Now posted online is "Design and Analysis of a Molecular Tool for Carbon Transfer
in Mechanosynthesis" [PDF]
by Damian G. Allis and K. Eric Drexler. This important new paper introduces
a novel carbon-transfer tool design (named "DC10c"), the first predicted to
exhibit several significant properties in combination.
Also available
online is Kinematic Self-Replicating Machines by Robert A.
Freitas Jr. and Ralph C. Merkle. This is the most comprehensive review ever
published about self-replicating machine systems, specifically kinematic
self-replicating machines: systems in which actual physical objects, not
mere patterns of information, undertake their own replication. The
book presents for the first time a detailed 137-dimensional map of
the entire kinematic replicator design space to assist future engineering
efforts. It has been cited in two articles appearing in the journal Nature this
year and appears well on its way to becoming the classic reference in
the field.
It's important to note that most of the systems described in KSRM are
only self-replicating in the sense that a set of blacksmith's tools is self-replicating.
The machinery can be used to make a physical copy, but only under external
control, and/or with artificially processed feedstock. Although runaway independent
self-replication has often been cited as a theoretical
danger, it is not a risk of currently planned molecular manufacturing
development.
CRN Task Force Progress Report
Recently CRN
announced the formation of a new Global Task Force to study the societal
implications of advanced nanotechnology. Bringing together a diverse group
of world-class experts from multiple disciplines, CRN is leading an historic,
collaborative effort to develop comprehensive recommendations for the safe
and responsible use of molecular manufacturing.
We're now up to 45 participants from six different countries on the CRN Task
Force. In addition, four organizations are publicly supporting this effort:
the Society of Manufacturing Engineers, the Society of Police Futurists International,
the Nanoethics Group, and the Nanotechnology Now web portal.
Currently underway is a major effort to identify and classify the most important
questions to be asked and answered in order to propose workable solutions
to the challenges posed by this powerful new technology. We expect to publish
our initial findings around the end of this year.
Dark Visions of a Fantastic Future
Flying cars are everywhere… large regions of the earth are under transparent domes with controlled weather… elsewhere, single buildings rise miles into the sky… huge areas of the ocean are covered with solar cells… tiny cameras watch everyone everywhere all the time, making sure crime does not pay…
In the near future, each of these visions will become possible. They could become reality. But will they? And should they?
That's from "Dark Visions of a Fantastic Future," a new essay written by CRN Executive Director Mike Treder for Future Brief. Here is the final paragraph:
Visions of a fantastic future could come true in our lifetimes. As we dream of the wonderful possibilities, we should take care also to envision darker scenarios. Because unless we can prevent the worst of the dangers—and there are many—we will deny ourselves any hope of realizing the benefits.
CRN Interviewed re Military Nanotechnology
For their most recent monthly report, a special issue on "Nanotechnology and
the Military," Nanotech-Now.com interviewed CRN's Chris Phoenix and
Mike Treder. Under the heading of "Considering Military and Homeland Security
Applications of Advanced Nanotechnology," they published our
thoughts about automated weapons, arms races, surveillance and privacy,
economic disruption, and more.
CRN Gets Podcasted
A podcast program called Small World conducted an
interview this month with CRN Executive Director Mike Treder. Topics
covered were the various definitions of nanotechnology; practical applications
of nanotechnology today and in the near future; nanofactories; the impact
of nanotechnology on the economy; military and terrorist use of nanotechnology;
the National Nanotechnology Initiative; and much more. The completed feature
is about 20 minutes long and can be downloaded
online.
We're on CNET's Blog 100 List
With more than 14 million blogs in existence and another 80,000 being created
each day, how is a person supposed to find the ones worth reading? That's
the question asked by CNET News.com, and they answer it with their Blog
100 list.
We are very proud that our Responsible
Nanotechnology blog was chosen by CNET News. It's quite an honor to
be ranked in the top 100 technology-oriented blogs among such stiff competition.
We will strive to remain worthy of this recognition.
CRN Goes to Chicago, Again
CRN's Chris Phoenix gave
a talk called "What is nanotechnology? And what does it have to do with
assembly technology?" at the Assembly Technology Expo in Chicago last month
(Mike Treder was in Chicago two months ago for the World Future Society's
annual meeting). Chris explained how and why molecular manufacturing goes
far beyond molecular "self-assembly" techniques.
CRN Goes to San Francisco
CRN is proud to be a media sponsor for the 13th
Foresight Conference on Advanced Nanotechnology. The title of the conference
this year is "Advancing Beneficial Nanotechnology: Focusing on the Cutting
Edge," and it will be divided into three stand-alone, complementary sessions — Vision,
Applications & Policy, and Research — spread over six days.
During the "Vision" session
on Sunday, Chris Phoenix will deliver a talk titled "Designing a Revolution." The
conference is October 22-27, 2005, in San Francisco, California. They've
got a great lineup of speakers, so we hope to see you there.
CRN Goes to Michigan
From San Francisco, Chris Phoenix will fly to Michigan where he will address
the 1st International IFAS Conference
on Nanotechnology, sponsored by Michigan State University's Agrifood
Nanotechnology Project. The conference will focus on what nanotech and nanofood
can learn from biotech and GMOs. Chris will be part of a concluding panel
discussion.
CRN Goes to Seattle
From Michigan, Chris Phoenix will fly to Seattle where he will address the
SAMPE (Society for the Advancement of Material and Process Engineering) Fall
Technical Conference. Chris will participate in a panel discussion on
occupational safety issues related to nanotechnology.
Feature Essay: Early Applications of
Molecular Manufacturing
Chris Phoenix, Director of Research, Center for Responsible Nanotechnology
Molecular manufacturing (MM) will be able to build a wide variety of products
-- but only if their designs can be specified. Recent
science essays have explained some reasons why nanofactory products
may be relatively easy to design in cases where we know what we want, and
only need to enter the design into a CAD program. Extremely dense functionality,
strong materials, integrated computers and sensors, and inexpensive full-product
rapid prototyping will combine to make product design easier.
However, there are several reasons why the design of certain products may
be quite difficult. Requirements for backward compatibility, advanced requirements,
complex or poorly understood environments, regulations, and lack of imagination
are only a few of the reasons why a broad range of nanofactory products will
be difficult to get right. Some applications will be a lot easier than others.
Products are manufactured for many purposes, including transportation, recreation,
communication, medical care, basic needs, military support, and environmental
monitoring, among others. This essay will consider a few products in each
of these categories, in order to convey a sense of the extent to which the
initial MM revolution, though still profound, may be limited by practical
design problems.
Transportation is simple in concept: merely move objects
or people from one place to another place. Efficient and effective transportation
is quite a bit more difficult. Any new transportation system needs to be safe,
efficient, rapid, and compatible with a wide range of existing systems. If
it travels on roads, it will need to comply with a massive pile of regulations.
If it uses installed pathways (future versions of train tracks), space will
have to be set aside for right-of-ways. If it flies, it will have to be extremely
safe to reassure those using it and avoid protest from those underneath.
Despite these problems, MM could produce fairly rapid improvements in transportation.
There would be nothing necessarily difficult about designing a nanofactory-built
automobile that exceeded all existing standards. It would be very cheap to
build, and fairly efficient to operate -- although air resistance would still
require a lot of fuel. Existing airplanes also could be replaced by nanofactory-built
versions, once they were demonstrated to be safe. In both cases, a great deal
of weight could be saved, because the motors would be many orders of magnitude
smaller and lighter, and the materials would be perhaps 100 times as strong.
Low-friction skins and other advances would follow shortly.
Molecular manufacturing could revolutionize access to space. Today's rockets
can barely get there; they spend a lot of energy just getting through the
atmosphere, and are not as efficient as they could be. The most efficient
rocket nozzle varies as atmospheric pressure decreases, but no one has built
a variable-nozzle rocket. Far more efficient, of course, would be to use an
airplane to climb above most of the atmosphere, as Burt Rutan did to win the
X Prize. But this has never been an option for large rockets. Another problem
is that the cost of building rockets is astronomical: they are basically hand-built,
and they must use advanced technology to minimize weight. This has caused
rocketry to advance very slowly. A single test of a new propulsion concept
may cost hundreds of millions of dollars.
When it becomes possible to build rockets with automated factories and materials
ten times as strong and light as today's, rockets will become cheap enough
to test by the dozen. Early advances could include disposable airplane components
to reduce fuel requirements; far less weight required to keep a human alive
in space; and far better instrumentation on test flights -- instrumentation
built into the material itself -- making it easier and faster to determine
the cause of failures. It seems likely that the cost of owning and operating
a small orbital rocket might be no more than the cost of owning a light airplane
today. Getting into space easily, cheaply, and efficiently will allow rapid
development of new technologies like high-powered ion drives and solar sails.
However, all this will rely on fairly advanced engineering -- not only for
the advanced propulsion concepts, but also simply for the ability to move
through the atmosphere quickly without burning up.
Recreation is typically an early beneficiary of inventiveness
and new technology. Because many sports involve humans interacting directly
with simple objects, advances in materials can lead to rapid improvements
in products. Some of the earliest products of nanoscale technologies (non-MM
nanotechnology) include tennis rackets and golf balls, and such things will
quickly be replaced by nano-built versions. But there are other forms of recreation
as well. Video games and television absorb a huge percentage of people's time.
Better output devices and faster computers will quickly make it possible to
provide users with a near-reality level of artificial visual and auditory
stimulus. However, even this relatively simple application may be slowed by
the need for interoperability: high-definition television has suffered substantial
delays for this reason.
A third category of recreation is neurotechnology, usually in the form of
drugs such as alcohol and cocaine. The ability to build devices smaller than
cells implies the possibility of more direct forms of neurotechnology. However,
safe and legal uses of this are likely to be quite slow to develop. Even illegal
uses may be slowed by a lack of imagination and understanding of the brain
and the mind. A more mundane problem is that early MM may be able to fabricate
only a very limited set of molecules, which likely will not include neurotransmitters.
Medical care will be a key beneficiary of molecular manufacturing.
Although the human body and brain are awesomely complex, MM will lead to rapid
improvement in the treatment of many diseases, and before long will be able
to treat almost every disease, including most or all causes of aging. The
first aspect of medicine to benefit may be minimally invasive tests. These
would carry little risk, especially if key results were verified by existing
tests until the new technology were proved. Even with a conservative approach,
inexpensive continuous screening for a thousand different biochemicals could
give doctors early indications of disease. (Although early MM may not be able
to build a wide range of chemicals, it will be able to build detectors for
many of them.) Such monitoring also could reduce the consequences of diseases
inadvertently caused by medical treatment by catching the problem earlier.
With full-spectrum continuous monitoring of the body's state of health, doctors
would be able to be simultaneously more aggressive and safer in applying treatments.
Individual, even experimental approaches could be applied to diseases. Being
able to trace the chemical workings of a disease would also help in developing
more efficient treatments for it. Of course, surgical tools could become far
more delicate and precise; for example, a scalpel could be designed to monitor
the type and state of tissue it was cutting through. Today, in advanced arthroscopic
surgery, simple surgical tools are inserted through holes the size of a finger;
a nano-built surgical robot with far more functionality could be built into
a device the width of an acupuncture needle.
In the United States today, medical care is highly regulated, and useful treatments
are often delayed by many years. Once the technology becomes available to
perform continuous monitoring and safe experimental treatments, either this
regulatory system will change, or the U.S. will fall hopelessly behind other
countries. Medical technologies that will be hugely popular with individuals
but may be opposed by some policy makers, including anti-aging, pro-pleasure,
and reproductive technologies, will probably be developed and commercialized
elsewhere.
Basic needs, in the sense of food, water, clothing, shelter,
and so on, will be easy to provide with even minimal effort. All of these
necessities, except food, can be supplied with simple equipment and structures
that require little innovation to develop. Although directly manufacturing
food will not be so simple, it will be easy to design and create greenhouses,
tanks, and machinery for growing food with high efficiency and relatively
little labor. The main limitation here is that without cleverness applied
to background information, system development will be delayed by having to
wait for many growing cycles. For this reason, systems that incubate separated
cells (whether plant, animal, or algae) may be developed more quickly than
systems that grow whole plants.
The environment already is being impacted as a byproduct
of human activities, but molecular manufacturing will provide opportunities
to affect it deliberately in positive ways. As with medicine, improving the
environment will have to be done with careful respect for the complexity of
its systems. However, also as with medicine, increased ability to monitor
large areas or volumes of the environment in detail will allow the effects
of interventions to be known far more quickly and reliably. This alone will
help to reduce accidental damage. Existing damage that requires urgent remediation
will in many cases be able to be corrected with far fewer side effects.
Perhaps the main benefit of molecular manufacturing for environmental cleanup
is the sheer scale of manufacturing that will be possible when the supply
of nanofactories is effectively unlimited. To deal with invasive species,
for example, it may be sufficient to design a robot that physically collects
and/or destroys the organisms. Once designed and tested, as many copies as
required could be built, then deployed across the entire invaded range, allowed
to work in parallel for a few days or weeks, and then collected. Such systems
could be sized to their task, and contain monitoring apparatus to minimize
unplanned impacts. Because robots would be lighter than humans and have better
sensors, they could be designed to do significantly less damage and require
far fewer resources than direct human intervention. However, robotic navigation
software is not yet fully developed, and it will not be trivial even with
million-times better computers. Furthermore, the mobility and power supply
of small robots will be limited. Cleanup of chemical contamination in soil
or groundwater also may be less amenable to this approach without significant
disruption.
Advanced military technology may have an immense impact on
our future. It seems clear that even a modest effort at developing nano-built
weapon systems will create systems that will be able to totally overwhelm
today's systems and soldiers. Even something as simple as multi-scale semi-automated
aircraft could be utterly lethal to exposed soldiers and devastating to most
equipment. With the ability to build as many weapons as desired, and with
motors, sensors, and materials that far outclass biological equivalents, there
would be no need to put soldiers on the battlefield at all. Any military operation
that required humans to accompany its machines would quickly be overcome.
Conventional aircraft could also be out-flown and destroyed with ease. In
addition to offensive weapons, sensing and communications networks with millions
if not billions of distributed components could be built and deployed. Software
design for such things would be far from trivial, however.
It is less clear that a modest military development effort would be able to
create an effective defense against today's high-tech attack systems. Nuclear
explosives would have to be stopped before the explosion, and intercepting
or destroying missiles in flight is not easy even with large quantities of
excellent equipment. Hypersonic aircraft and battle lasers are only now being
developed, and may be difficult to counter or to develop independently without
expert physics knowledge and experience. However, even a near parity of technology
level would give the side with molecular manufacturing a decisive edge in
a non-nuclear exchange, because they could quickly build so many more weapons.
It is also uncertain what would happen in an arms race between opponents that
both possessed molecular manufacturing. Weapons would be developed very rapidly
up to a certain point. Beyond that, new classes of weapons would have to be
invented. It is not yet known whether offensive weapons will in general be
able to penetrate shields, especially if the weapons of both sides are unfamiliar
to their opponents. If shields win, then development of defensive technologies
may proceed rapidly until all sides feel secure. If offense wins, then a balance
of terror may result. However, because sufficient information may allow any
particular weapon system to be shielded against, there may be an incentive
to continually develop new weapons.
This essay has focused on the earliest applications of molecular manufacturing.
Later developments will benefit from previous experience, as well as from
new software tools such as genetic algorithms and partially automated design.
But even a cursory review of the things we can plan for today and the problems
that will be most limiting early in the technology's history shows that molecular
manufacturing will rapidly revolutionize many important areas of human endeavor.
* * * * * * * * * * * * * * * *
FUNDRAISING ALERT!
Recent developments in efforts to roadmap the
technological steps towards molecular manufacturing make the work of CRN even
more important. It is critical that we examine the global implications of
this rapidly emerging technology, and begin designing wise and effective policy.
That's why we have formed the CRN
Task Force.
But it won't be easy. We need to grow, and rapidly, to meet the expanding
challenge.
Your donation to CRN will help us to achieve that growth. We rely largely
on individual donations and small grants for our survival.
To make a contribution on-line, click
here. This is important work and we welcome your participation.
Thank you!
* * * * * * * * * * * * * * * *
C-R-Newsletter #33 August 31, 2005
CRN
Forms Policy Task Force
Eric
Drexler Joins Nanorex
Connecticut
Schools Go Nano
NASA
Website Covers CRN Work
CRN
Goes to Vermont
CRN
Goes to Chicago
CRN
Goes to Bootcamp
Dimensions
of Development
13th
Foresight Conference
Feature
Essay: Molecular Manufacturing Design Software
=========
We're
a little late getting the C-R-Newsletter out this month, but as you can
see, we've been extremely busy. To keep up with the latest happenings
on a daily basis, be sure to check our Responsible
Nanotechnology weblog.
The big news this month is that CRN announced the formation of a new Global Task Force to study the societal implications of advanced nanotechnology. Bringing together a diverse group of world-class experts from multiple disciplines, CRN will lead an historic, collaborative effort to develop comprehensive policy recommendations for the safe and responsible use of molecular manufacturing.
Just two weeks after the initial announcement, which mentioned four "charter members" of the CRN Task Force, we're up to 39 participants from six different countries. In addition, three organizations are publicly supporting this effort: the Society of Manufacturing Engineers, the Society of Police Futurists International, and the Nanotechnology Now web portal.
Several online planning sessions have been held, and the CRN Task Force is now beginning its initial task: to itemize the necessary information that must be available in order to design wise and effective policy.
Eric Drexler Joins Nanorex
Nanorex, a molecular engineering software company based in Michigan, has named Dr. K. Eric Drexler as the company's Chief Technical Advisor. The company said that Drexler will play a leading role in shaping Nanorex's product strategy and advancing the company’s academic outreach programs.
Often described as the 'father of nanotechnology', Eric Drexler is on the Board of Advisors for CRN. His groundbreaking theoretical research has been the basis for three books, including Nanosystems: Molecular Machinery, Manufacturing, and Computation, and numerous journal articles. Last year, he collaborated with Chris Phoenix, CRN's Director of Research, on "Safe Exponential Manufacturing", published in the Institute of Physics journal Nanotechnology.
In 1986, Drexler founded the Foresight Nanotech Institute, a non-profit think tank and public interest organization focused on nanotechnology. He was awarded a PhD from MIT in Molecular Nanotechnology (the first degree of its kind). Drexler is expected to be deeply involved in the project to develop a Technology Roadmap for Productive Nanosystems, recently announced by Foresight and the Battelle research organization.
Connecticut Schools Go Nano
Connecticut Governor M. Jodi Rell has enacted a new law requiring the Commissioner of Higher Education in her state to review the inclusion of nanotechnology, molecular manufacturing and advanced and developing technologies at institutions of higher education.
CRN is pleased to note that this measure specifically designates molecular manufacturing as something that should be studied for inclusion in the curriculum at institutions of higher education. We encourage other states -- and indeed, other countries -- to follow Connecticut's lead.
NASA Website Covers CRN Work
The NASA Institute for Advanced Concepts (NIAC), an independent, NASA-funded organization located in Atlanta, Georgia, was created to promote forward-looking research on radical space technologies that will take 10 to 40 years to come to fruition. Last year, NIAC awarded a grant to Chris Phoenix, CRN's Director of Research, to conduct a feasibility study of nanoscale manufacturing.
On NASA's website, an article titled "The Next Giant Leap" highlights the work NIAC is funding in nanotechnology research, and includes a description of the 112-page report Chris presented to them. We congratulate Chris on this much-deserved recognition.
CRN Goes to Vermont
In late July, CRN principals Mike Treder and Chris Phoenix were invited to participate in a special workshop on 'geoethical nanotechnology', held at a beautiful mountain retreat in Vermont. Our gracious host was Martine Rothblatt, CEO of United Therapeutics Corporation, and founder of the Terasem Movement Foundation.
Among those making presentations were Ray Kurzweil, CEO of Kurzweil Technologies; Professor Frank Tipler of Tulane University; Douglas Mulhall, author of Our Molecular Future; and Dr. Barry Blumberg, a Nobel Prize-winner in medicine and Founding Director of the NASA Astrobiology Institute. CRN's PowerPoint presentation for the event is available online here.
Geoethical nanotechnology is defined as: the development and implementation under a global regulatory framework of machines capable of assembling molecules into a wide variety of objects, in a broad range of sizes, and in potentially vast quantities.
CRN Goes to Chicago
Also in July, CRN Executive Director Mike Treder gave talks at two events in Chicago. First, at a special nanotech symposium [PDF], Mike delivered a presentation called "The Flat Horizon Problem: Nanotechnology on an Upward Slope" [PPT].
Then, during the annual conference of the World Future Society, Mike made a speech titled, "Do Sweat the Small Stuff: Why Everyone Should Care About Nanotechnology" [PPT]. The conference, WorldFuture 2005: Foresight, Innovation, and Strategy, was managed excellently and enjoyed huge attendance.
CRN Goes to Bootcamp
In mid-July, CRN Research Director Chris Phoenix spent four days in Washington DC at a Nano Training Bootcamp sponsored by the ASME. He called it "quite a brain-stretcher." Topics included quantum mechanics, optics, thermoelectrics, nanolithography, and much more. Chris provided us with extensive blog reports during the event, so you can read about all the tech-talk from Day One, Day Two, Day Three, and Day Four.
Dimensions of Development
Many factors will determine how soon and how safely molecular manufacturing is integrated into society, including where, how openly, and how rapidly it is developed. Because nanotech manufacturing could be so disruptive and destabilizing, it is essential that we learn as much as possible about those factors and others. The more we know, the better we may be able to guide and manage this revolutionary transformation.
Mike Treder's latest essay for Future Brief describes six different dimensions — Number, Style, Venue, Approach, Program, and Pace — along which molecular manufacturing may be developed. Making effective policy for the safe and responsible use of advanced nanotechnology will require a deep and comprehensive understanding of all six dimensions. To be effective, a coordinated and integrated strategy of multiple complimentary policies must be designed and implemented. (Note: At the time the essay was published, the CRN Global Task Force on Implications and Policy had not yet been announced.)
13th Foresight Conference
CRN is proud to be a media sponsor for the 13th Foresight Conference on Advanced Nanotechnology. The title of the conference this year is "Advancing Beneficial Nanotechnology: Focusing on the Cutting Edge," and it will be divided into three stand-alone, complementary sessions — Vision, Applications & Policy, and Research — spread over six days.
The
conference is October 22-27, 2005, in San Francisco, California. They've
got a great lineup of speakers, so we hope to see you there.
Feature
Essay: Molecular
Manufacturing Design Software
Chris Phoenix, Director of Research, CRN
Nanofactories, controlled by computerized blueprints, will be able to build a vast range of high performance products. However, efficient product design will require advanced software.
Different kinds of products will require different approaches to design. Some, such as high-performance supercomputers and advanced medical devices, will be packed with functionality and will require large amounts of research and invention. For these products, the hardest part of design will be knowing what you want to build in the first place. The ability to build test hardware rapidly and inexpensively will make it easier to do the necessary research, but that is not the focus of this essay.
There are many products that we easily could imagine and that a nanofactory easily could build if told exactly how. But as any computer programmer knows, it's not easy to tell a computer what you want it to do — it's more or less like trying to direct a blind person to cook a meal in an unfamiliar kitchen. One mistake, and the food is spilled or the stove catches fire.
Computer users have an easier time of it. To continue the analogy, if the blind person had become familiar with the kitchen, instructions could be given on the level of "Get the onions from the left-hand vegetable drawer" rather than "Move your hand two inches to your right... a bit more... pull the handle... bend down and reach forward... farther... open the drawer... feel the round things?" It is the job of the programmer to write the low-level instructions that create appliances from obstacles.
Another advantage of modern computers, from the user's point of view, is their input devices. Instead of typing a number, a user can simply move a mouse, and a relatively simple routine can translate its motion into the desired number, and the number into the desired operation such as moving a pointer or a scroll bar.
Suppose I wanted to design a motorcycle. Today, I would have to do engineering to determine stresses and strains, and design a structure to support them. The engineering would have to take into account the materials and fasteners, which in turn would have to be designed for inexpensive assembly. But these choices would limit the material properties, perhaps requiring several iterations of design. And that's just for the frame.
Next, I would have to choose components for a suspension system, configure an engine, add an electrical system and a braking system, and mount a fuel tank. Then, I would have to design each element of the user interface, from the seat to the handgrips to the lights behind the dials on the instrument panel. Each thing the user would see or touch would have to be made attractive, and simultaneously specified in a way that could be molded or shaped. And each component would have to stay out of the way of the others: the engine would have to fit inside the frame, the fuel tank might have to be molded to avoid the cylinder heads or the battery, and the brake lines would have to be routed from the handlebars and along the frame, adding expense to the manufacturing process and complexity to the design process.
As I described in last month's essay, most nanofactory-built human-scale products will be mostly empty space due to the awesomely high performance of both active and passive components. It will not be necessary to worry much about keeping components out of each other's way, because the components will be so small that they can be put almost anywhere. This means that, for example, the frame can be designed without worrying where the motor will be, because the motor will be a few microns of nanoscale motors lining the axles. Rather than routing large hydraulic brake lines, it will be possible to run highly redundant microscopic signal lines controlling the calipers — or more likely, the regenerative braking functionality built into the motors.
It will not be necessary to worry about design for manufacturability. With a planar-assembly nanofactory, almost any shape can be made as easily as any other, because the shapes are made by adding sub-micron nanoblocks to selected locations in a supported plane of the growing product. There will be less constraint on form than there is in sand casting of metals, and of course far more precision. This also means that what is built can contain functional components incorporated in the structure. Rather than building a frame and mounting other pieces later, the frame can be built with all components installed, forming a complete product. This does require functional joints between nanoblocks, but this is a small price to pay for such flexibility.
To specify functionality of a product, in many cases it will be sufficient to describe the desired functionality in the abstract without worrying about its physical implementation. If every cubic millimeter of the product contains a networked computer — which is quite possible, and may be the default — then to send a signal from point A to point B requires no more than specifying the points. Distributing energy or even transporting materials may not require much more attention: a rapidly rotating diamond shaft can transport more than a watt per square micron, and would be small enough to route automatically through almost any structure; pipes can be made significantly smaller if they are configured with continually inverting liners to reduce drag.
Thus, to design the acceleration and braking behavior of the motorcycle, it might be enough to specify the desired torque on the wheels as a function of speed, tire skidding, and brake and throttle position. A spreadsheet-like interface could calculate the necessary power and force for the motors, and from that derive the necessary axle thickness. The battery would be fairly massive, so the user would position it, but might not have to worry about the motor-battery connection, and certainly should not have to design the motor controller.
In order to include high-functionality materials such as motor arrays or stress-reporting materials, it would be necessary to start with a library of well-characterized "virtual materials" with standard functionality. This approach could significantly reduce the functional density of the virtual material compared to what would be possible with a custom-designed solution, but this would be acceptable for many applications, because functional density of nano-built equipment may be anywhere from six to eighteen orders of magnitude better than today's equipment. Virtual materials could also be used to specify material properties such as density and elasticity over a wide range, or implement active materials that changed attributes such as color or shape under software control.
Prototypes as well as consumer products could be heavily instrumented, warning of unexpected operating conditions such as excessive stress or wear on any part. Rather than careful calculations to determine the tradeoff between weight and strength, it might be better to build a first-guess model, try it on increasingly rough roads at increasingly high speeds, and measure rather than calculate the required strength. Once some parameters had been determined, a new version could be spreadsheeted and built in an hour or so at low cost. It would be unnecessary to trade time for money by doing careful calculations to minimize the number of prototypes. Then, for a low-performance application like a motorcycle, the final product could be built ten times stronger than was thought to be necessary without sacrificing much mass or cost.
There are only a few sources of shape requirements. One is geometrical: round things roll, flat things stack, and triangles make good trusses. These shapes tend to be simple to specify, though some applications like fluid handling can require intricate curves. The second source of shape is compatibility with other shapes, as in a piece that must fit snugly to another piece. These shapes can frequently be input from existing databases or scanned from an existing object. A third source of shape is user preference. A look at the shapes of pen barrels, door handles, and eyeglasses shows that users are pleased by some pretty idiosyncratic shapes.
To input arbitrary shapes into the blueprint, it may be useful to have some kind of interface that implements or simulates a moldable material like clay or taffy. A blob could simply be molded or stretched into a pleasing shape. Another useful technique could be to present the designer or user with several variations on a theme, let them select the best one, and build new variations on that until a sufficiently pleasing version is produced.
Although
there is more to product design than the inputs described here, this should
give some flavor of how much more convenient it could be with computer-controlled
rapid prototyping of complete products. Elegant computer-input devices,
pervasive instrumentation and signal processing, virtual material libraries,
inexpensive creation of one-off spreadsheeted prototypes, and several
other techniques could make product design more like a combination of
graphic arts and computer programming than the complex, slow, and expensive
process it is today.
* * *
* * * * * * * * * * * * *
FUNDRAISING ALERT!
Recent developments in efforts to roadmap the
technological steps towards molecular manufacturing make the work of CRN even
more important.
It is critical that we examine the global implications of this rapidly emerging
technology, and begin designing wise and effective policy. That's why we have
formed the CRN
Task Force.
But it won't be easy. We need to grow, and rapidly, to meet the expanding
challenge.
Your donation to CRN will help us to achieve that growth. We rely largely
on individual donations and small grants for our survival.
To make a contribution on-line, click
here. This is important work and we welcome your participation!
* * * * * * * * * * * * * * * *
C-R-Newsletter #32 July 14, 2005
Nanotech
Roadmap Initiative
New
Nano Movie
Russian
CRN Site Online
Nanotech
Q&A for Russia
Nano-techno-logy
State
of the Future 2005
Nanotechnology
Workshop Webcast
CRN
goes to Chicago
Feature
Essay: Fast Development of Nano-Manufactured Products
FUNDRAISING
ALERT!
=========
Things are moving
very quickly throughout the nano-world and at CRN. We’ll recap some
of the highlights here — but to keep up with the latest developments,
be sure to check our Responsible
Nanotechnology weblog. Thanks!
Nanotech Roadmap Initiative
Foresight Nanotech Institute, in cooperation with Battelle, a global research
organization, has
announced its intent to develop a "Technology Roadmap for Productive
Nanosystems." CRN strongly encourages a cooperative program to map all the
steps that will lead to molecular manufacturing. We have even outlined a series
of studies that could go a long way toward meeting this goal. A combined
effort — involving business, government, academic, and nonprofit
participants — appears safest to us. This is especially true if
numerous international partners are included, the more the better.
In principle, we
support the idea of a collaborative technical roadmap project. It's
not yet clear, however, if the Foresight announcement meets our description.
We look forward to hearing more about it in the near future.
New Nano Movie
A new "must-see" short film has been produced using computer animation to
assist in visualizing nanosystems and molecular manufacturing. Productive
Nanosystems: from Molecules to Superproducts, is a collaborative effort
of animator and engineer John
Burch and pioneer nanotechnologist Dr.
K. Eric Drexler, made possible through a challenge grant from Mark
Sims and NanoRex. The four-minute film depicts an animated view
of a nanofactory and demonstrates key steps in a process that converts
simple molecules into a billion-CPU laptop computer. The movie
file is 60+ MB. It will take a while to download, but it's definitely
worth it.
Russian CRN Site Online
CRN is very pleased to announce that several pages from our main website have
been translated into the Russian language and are
posted on the Internet. Denis
Tarasov, a Research Scientist in the Biology Department of Kazan
State University in Russia, did most of the translation work. We
are grateful for his assistance.
We now have CRN web pages available in five languages: English, Chinese, Spanish, Portuguese,
and Russian.
If you think you can help with other languages, please let
us know.
Nanotech Q&A for Russia
Last month, NanoNewsNet, a web portal for nanotechnology news and
research in Russia, interviewed CRN Executive Director Mike
Treder for their site. The interview is posted
online in the Russian language. We have an English translation here.
Nano-techno-logy
Three Greek words — nano (dwarf or tiny), techne (craft or skill), and
logos (science or learning) — combine to make nano-techno-logy: applying
science at a tiny scale to the craft or skill of building. Miracle predictions
about nanotech's potential are common, as are dire warnings about the technology's
risks. So, are the pessimists or the optimists right?
To find out, read this new
essay by Mike Treder, published by Future Brief.
State of the Future 2005
Many people still do not appreciate how fast science and technology will change
over the next 25 years, and given this rapid development along several different
fronts, the possibility of technology growing beyond human control must now
be taken seriously, according to a
new report produced by the United Nations University's Millennium
Project.
State of the Future 2005 analyzes current global trends and examines
in detail some of the present and future challenges facing the world. As a
consultant to the UN University's Millennium Project, CRN’s Mike Treder
was involved with developing some
of the findings contained in the report.
Nanotechnology Workshop Webcast
The Terasem Movement, Inc., a non-profit foundation focused on geoethical
nanotechnology, has announced that an interactive
webcast featuring Ray Kurzweil, Frank Tipler, James Hughes, Max More,
Doug Mulhall, Mike Treder and others at its Geoethical
Nanotechnology Workshop will be openly accessible from 8AM-6PM EST
on Wednesday, July 20th.
Viewers of the interactive webcast are invited to email or IM (instant-message)
questions directed to the presenters throughout the meeting. Each hour, some
of these will be selected for the featured speakers to answer. The webcast
will feature simultaneous transmission of audio, video, and PowerPoint presentations.
Geoethical nanotechnology is the development and implementation under a global
regulatory framework of machines capable of assembling molecules into a wide
variety of objects, in a broad range of sizes, and in potentially vast quantities.
CRN goes to Chicago
CRN's Mike Treder is speaking at two events in Chicago later this month. On
Friday, July 29, at a special Symposium
on Nanotechnology [PDF], Mike will deliver a presentation called "The
Flat Horizon Problem: Nanotechnology on an Upward Slope."
The next day, Saturday, July 30, during the annual conference of the World
Future Society, Mike is giving a talk titled, "Do Sweat the Small Stuff: Why
Everyone Should Care About Nanotechnology." The conference, WorldFuture
2005: Foresight, Innovation, and Strategy, is at the Chicago Hilton
and Towers. If you're going to be there, make sure to say hello to Mike.
Feature Essay: Fast Development of Nano-Manufactured
Products
Chris Phoenix, Director of Research, Center for Responsible Nanotechnology
The extremely high performance of the products of molecular
manufacturing will make the technology transformative—but it is
the potential for fast development that will make it truly disruptive.
If it took decades of research to produce breakthrough products, we would
have time to adjust. But if breakthrough products can be developed quickly,
their effects can pile up too quickly to allow wise policymaking or adjustment.
As if that weren't bad enough, the anticipation of rapid development could
cause additional problems.
How quick is "quickly?" Given a programmable factory that can make a product
from its design file in a few hours, a designer could create a newly improved
version every day. Today, building prototypes of a product can take weeks,
so designers have to take extra time to double-check their work. If building
a prototype takes less than a day, it will often be more efficient to build
and test the product rather than taking time to double-check the theoretical
design. (Of course, if taken to extremes, this can encourage sloppy work that
costs more time to fix in the long run.)
In addition to being faster, prototyping also would be far cheaper. A nanofactory would
go through the same automated operations for a single prototype copy as for
a production run, so the prototype should cost no more per unit than the final
product. That's quite a contrast with today, where rapid prototyping can cost
thousands of dollars per component. And it means that destructive testing
will be far less painful. Let's take an example. Today, a research rocket
might cost hundreds of dollars to fuel, but hundreds of thousands to build.
At that rate, tests must be held to a minimum number, and expensive and time-consuming
efforts must be made to eliminate all possible sources of failure and gather
as much data as possible from each test. But if the rocket cost only hundreds
of dollars to build—if a test flight cost less than $1000, not counting
support infrastructure—then tests could be run as often as convenient,
requiring far less support infrastructure, saving costs there as well. The
savings ripple out: with less at stake in every test, designers could use
more advanced and less well-proved technologies, some of which would fail
but others of which would increase performance. Not only would the product
be developed faster, but it also would be more advanced, and have a lot more
testing.
The equivalence between prototype and production manufacturing has an additional
benefit. Today, products must be designed for two different manufacturing
processes—prototyping and scaled-up production. Ramping up production
has its own costs, such as rearranging production lines and training workers.
But with direct-from-blueprint building, there would be no need to keep two
designs in mind, and also no need to expend time and money ramping up production.
When a design was finalized, it could immediately be shipped to as many nanofactories
as desired, to be built efficiently and almost immediately. (For those just
joining us, the reason nanofactories aren't scarce is that a nanofactory would
be able to build another nanofactory on command, needing only data and supplies
of a few refined chemicals.) A product design isn't really proved until people
buy it, and rolling out a new product is expensive and risky today—after
manufacture, the product must be shipped and stored in quantity, waiting for
people to buy it. With last-minute nanofactory manufacturing, the product
rollout cost could be much lower, reducing the overhead and risk of market-testing
new ideas.
There are several other technical reasons why products could be easier to
design. Today's products are often crammed full of functionality, causing
severe headaches for designers trying to make one more thing fit inside the
package. Anyone who's looked under the hood of a 1960 station wagon and compared
it with a modern car's engine, or studied the way chips and wires are packed
into every last nook and cranny of a cell phone, knows how crowded products
can get. But molecular manufactured products will be many orders of magnitude
more compact; this is true for sensors, actuators, data processing, energy
transformation, and even physical structure. What this means is that any human-scale
product will be almost entirely empty space. Designers will be able to include
functions without worrying much about where they will physically fit into
the product. This ability to focus on function will simplify the designer's
task.
The high performance of molecularly precise nanosystems also means that designers
can afford to waste a fair amount of performance in order to simplify the
design. For example, instead of using a different size of motor for every
different-sized task, designers might choose from only two or three standard
sizes that might differ from each other by an order of magnitude or more.
In today's products, using a thousand-watt motor to do a hundred-watt motor's
job would be costly, heavy, bulky, and probably an inefficient use of energy
besides. But nano-built motors have been calculated to be at least a million
times as powerful. That thousand-watt motor would shrink to the size of a
grain of sand. Running it at low power would not hurt its efficiency, and
it wouldn't be in danger of overheating. It wouldn't cost significantly more
to build than a carefully-sized hundred-watt motor. And at that size, it could
be placed wherever in the product was most convenient for the designer.
Another potential advantage of having more performance than needed is that
design can be performed in stages. Instead of planning an entire product at
once, integrated from top to bottom, designers could cobble together a product
from a menu of lower-level solutions that were already designed and understood.
For example, instead of a complicated system with lots of custom hardware
to be individually specified, designers could find off-the-shelf modules that
had more features than required, string them together, and tweak their specifications
or programming to configure their functionality to the needed product—leaving
a lot of other functionality unused. Like the larger-than-necessary motor,
this approach would include a lot of extra stuff that was put in simply to
save the designer's time; however, including all that extra stuff would cost
almost nothing. This approach is used today in computers. A modern computer
spends at least 99% of its time and energy on retroactively saving time for
its designers. In other words, the design is horrendously inefficient, but
because computer hardware is so extremely fast, it's better to use trillions
of extra calculations than to pay the designer even $10 to spend time on making
the program more efficient. A modern personal computer does trillions of calculations
in a fraction of an hour.
Modular design depends on predictable modules—things that work exactly
as expected, at least within the range of conditions they are used in. This
is certainly true in computers. It will also be true in molecular manufacturing,
thanks to the digital nature of covalent bonds. Each copy of a design that
has the same bond patterns between the atoms will have identical behavior.
What this means is that once a modular design is characterized, designers
can be quite confident that all subsequent copies of the design will be identical
and predictable. (Advanced readers will note that isotopes can make a difference
in a few cases, but isotope number is also discrete and isotopes can be sorted
fairly easily as necessary to build sensitive designs. Also, although radiation
damage can wipe out a module, straightforward redundancy algorithms will take
care of that problem.)
With all these advantages, development of nano-built products, at least to
the point of competing with today's products, appears to be easier in some
important ways than was development of today's products. It's worth spending
some thought on the implications of that. What if the military could test-fire
a new missile or rocket every day until they got it right? How fast would
the strategic balance of power shift, and what is the chance that the mere
possibility of such a shift could lead to pre-emptive military strikes? What
if doctors could build new implanted sensor arrays as fast as they could find
things to monitor, and then use the results to track the effects of experimental
treatments (also nano-built rapid-prototyped technology) before they had a
chance to cause serious injury? Would this enable doctors to be more aggressive—and
simultaneously safer—in developing new lifesaving treatments? If new
versions of popular consumer products came out every month—or even every
week—and consumers were urged to trade up at every opportunity, what
are the environmental implications? What if an arms race developed between
nations, or between police and criminals? What if products of high personal
desirability and low social desirability were being created right and left,
too quickly for society to respond? A technical essay is not the best place
to get into these questions, but these issues and more are directly raised
by the possibility that molecular manufacturing nanofactories will open the
door to true rapid prototyping.
* * * * * * * * * * * * * * * *
FUNDRAISING ALERT!
Recent developments in efforts to roadmap the
technological steps towards molecular manufacturing make the work of CRN even
more important.
It is critical that we examine the global implications of this rapidly emerging
technology, and CRN continues to be in the forefront of this discussion.
But we need to grow, and rapidly, to meet the expanding need.
Your donation to CRN will help us to achieve that growth. We rely largely
on individual donations and small grants for our survival.
To make a contribution on-line, click
here. This is important work and we welcome your participation!
* * * * * * * * * * * * * * * *
C-R-Newsletter #31 June 10, 2005
NanoWorld
Weapons Warning
Citizen
Conferences on Technology
CRN
Policy Debate
Nanofuture:
What's Next for Nanotechnology
CRN
goes to Baltimore
Russian
Translation Coming Soon
Reminder
about Symposium on Nanotechnology
Feature
Essay: Sudden Development of Molecular Manufacturing
FUNDRAISING
ALERT!
=========
Even
more than usual, things are happening fast at CRN. We'll recap some of
the highlights here—but to keep up with the latest developments,
be sure to check our Responsible
Nanotechnology weblog.
NanoWorld Weapons Warning
"Nano
could lead to new WMDs"
Does that sound like one of CRN's
warnings? Not this time. It's the headline on a recent UPI article by Charles
Choi, in which he interviews scientists from the University of Mexico
and the University of California.
The scary thing is that they
aren't focusing on advanced nanotechnology -- destructive new devices
produced in mass quantity with molecular manufacturing -- because they don't
have to. They make a convincing point just talking about improved (is that
the right word?) chemical and biological weapons.
Already we're hearing sabers rattle and drums beat with the proposed weaponization
of space. From there, it's a short step to military
use of molecular machine systems with exponential manufacturing potential
-- and at that point we're right on the edge of a very
steep cliff.
Citizen Conferences on Technology
An innovative
way to "stimulate broad and intelligent social debate on technological
issues," pioneered in the 1980s by the Danish Board of Technology, is now
getting underway in
the UK, with a focus on nanotechnology.
We think this is a good sign. Public
involvement in determining safe
development and responsible use of advanced nanotechnology will be
vital. CRN
research suggests that these issues are likely to arise sooner
than many expect. The surest way to avoid the worst dangers is
to understand them in advance and take assertive action to prevent
them.
CRN Policy Debate
After reading Executive Director Mike Treder's essay on "War,
Interdependence, and Nanotechnology," C-R-Network member Steve Burgess
engaged Mike in a friendly email 'debate' on nanotechnology policy. The
discussion revolved around instituting fair distribution of nanotech-produced
abundance as a way of preventing an uncontrollable arms race.
Issues covered were: 1) How can such distribution be imposed with a minimum
of force and conflict? 2) Is it even ethical to attempt to impose a global
system of abundance, superseding national sovereignties? 3) Even if the basis
for a society based on lack of scarcity exists in the future, will evolved
human psychology be able to make the transition without widespread fighting?
We posted the back and forth responses on
our blog.
Nanofuture: What's Next for Nanotechnology
Flying cars, space travel for everyone, the elimination of poverty and hunger,
and powerful new tools to combat disease, and even aging. These are some of
the amazing predicted developments of nanotechnology, the coming science of
designing and building machines at the molecular and atomic levels. Will this
new scientific revolution be for better or worse?
That's from the publisher's description of Nanofuture:
What's Next for Nanotechnology, a new nonfiction book by Dr. J.
Storrs (Josh) Hall. We haven't read it yet, but based on the description
and the rave
reviews, this looks like a must-read. We wish Josh great success with
his book.
CRN goes to Baltimore
About 50 engineers and other interested people attended an Emerging
Technologies Forum titled "The Next Industrial Revolution: Molecular
Nanotechnology and Manufacturing" in Baltimore last week. CRN Executive
Director Mike Treder was asked to moderate the event, which was sponsored
by the Society of Manufacturing Engineers (SME). Speakers included Scott
Mize, president of the Foresight
Institute, Dr. Joseph Jacobson from the Center
for Bits and Atoms at MIT, Kevin Lyons of the National
Science Foundation, Dr. Dennis Swyt of the NIST,
and Dr. Richard Colton from the U.S.
Naval Research Laboratory.
This forum was the second in a series intended to educate the manufacturing
sector about what they can expect from advanced nanotechnology. CRN's Chris
Phoenix spoke at the first
event, which was last month in Minneapolis, Minnesota. We applaud SME
for being forward-looking and helping to prepare their members for the next
industrial revolution.
Russian Translation Coming Soon
We are excited to announce that a volunteer is translating several of CRN's
web pages into the Russian language. Other volunteers from Russia’s Nanotechnology
News Network are helping to edit and verify the translation.
When this is completed, we will have CRN web pages in Chinese, Spanish, Portuguese,
and Russian, in addition to English. Next, we'll be looking for people to
help with translations into Arabic, Bengali, French, German, Hindi, Japanese,
and perhaps other languages. We want everyone to learn about responsible nanotechnology!
Reminder about Symposium on Nanotechnology
In connection with their hugely popular annual conference, the World Future
Society has announced "an exploration series designed to provide an outline
of several critical new fields with the potential for significant impact on
the social, economic, and cultural fabric of modern society." For this year,
they have organized a Symposium
on Nanotechnology [PDF], which CRN's Mike
Treder will assist in presenting. It's happening in Chicago on July
29, 2005. Hope to see you there!
Feature Essay: Sudden Development of Molecular
Manufacturing
Chris Phoenix, Director of Research, Center for Responsible Nanotechnology
Development of molecular manufacturing technology probably will not be gradual,
and will not allow time to react to incremental improvements. It is often
assumed that development must be gradual, but there are several points at
which minor improvements to the technology will cause massive advances in
capability. In other words, at some points, the capability of the technology
can advance substantially without breakthroughs or even much R&D.
These jumps in capability could happen quite close together, given the pre-design
that a well-planned development program would certainly do. Advancing from
laboratory demos all the way to megatons of easily designed, highly advanced
products in a matter of months appears possible. Any policy that will be needed
to deal with the implications of such products must be in place before the
advances start.
The first jump in capability is exponential manufacturing. If a manufacturing
system can build an identical copy, then the number of systems, and their
mass and productivity, can grow quite rapidly. However, the starting point
is quite small; the first device may be one million-billionth of a gram (100
nanometers). It will take time for even exponential growth to produce a gram
of manufacturing systems. If a copy can be built in a week, then it will take
about a year to make the first gram. A better strategy will be to spend the
next ten months in R&D to reduce the manufacturing
time to one day, at which point it will take less than two months to make
the first gram. And at that point, expanding from the first gram to the first
ton will take only another three weeks.
It's worth pointing out here that nanoscale machinery is vastly more powerful
than larger machinery. When a machine shrinks, its power density and functional
density improve. Motors could be a million times more powerful than today's;
computers could be billions of times more compact. So a ton of nano-built
stuff is a lot more powerful than a ton of conventional product. Even though
the products of tiny manufacturing systems will themselves be small, they
will include computers and medical devices. A single kilogram of nanoscale
computers would be far more powerful than the sum of all computers in existence
today.
The second jump in capability is nanofactories—integrated manufacturing
systems that can make large products with all the advantages of precise nanoscale
machinery. It turns out that nanofactory design can be quite simple and scalable,
meaning that it works the same regardless of the size. Given a manufacturing
system that can make sub-micron blocks ("nanoblocks"), it doesn't take a lot
of additional work to fasten those blocks together into a product. In fact,
a product of any size can be assembled in a single plane, directly from blocks
small enough to be built by single nanoscale manufacturing systems, because
assembly speed increases as block size decreases. Essentially, a nanofactory
is just a thin sheet of manufacturing systems fastened side by side. That
sheet can be as large as desired without needing a re-design, and the low
overhead means that a nanofactory can build its own mass almost as fast as
a single manufacturing system. Once the smallest nanofactory has been built,
kilogram-scale and ton-scale nanofactories can follow in a few weeks.
The third jump in capability is product design. If it required a triple Ph.D.
in chemistry, physics, and engineering to design a nanofactory product, then
the effects of nanofactories would be slow to develop. But if it required
a triple Ph.D. in semiconductor physics, digital logic, and operating systems
to write a computer program, the software industry would not exist. Computer
programming is relatively easy because most of the complexity is hidden—encapsulated
and abstracted within simple, elegant high-level commands. A computer programmer
can invoke billions of operations with a single line of text. In the case
of nanofactory product design, a good place to hide complexity is within the
nanoblocks that are fastened together to make the product. A nanoblock designer
might indeed need a triple Ph.D. However, a nanoblock can contain many millions
of features—enough for motors, a CPU, programmable networking and connections,
sensors, mechanical systems, and other high-level components.
Fastening a few types of nanoblocks together in various combinations could
make a huge range of products. The product designer would not need to know
how the nanoblocks worked—only what they did. A nanoblock is quite a
bit smaller than a single human cell, and a planar-assembly nanofactory would
impose few limits on how they were fastened together. Design of a product
could be as simple as working with a CAD program to specify volumes to be
filled and areas to be covered with different types of nanoblocks.
Because the internal design of nanoblocks would be hidden from the product
designer, nanoblock designs could be changed or improved without requiring
product designers to be retrained. Nanoblocks could be designed at a functional
level even before the first nanofactory could be built, allowing product designers
to be trained in advance. Similarly, a nanofactory could be designed in advance
at the nanoblock level. Although simple design strategies will cost performance, scaling
laws indicate that molecular-manufactured machinery will have performance
to burn. Products that are revolutionary by today's standards, including
the nanofactory itself, could be significantly less complex than either
the software or the hardware that makes up a computer—even a 1970's-era
computer.
The design of an exponential molecular manufacturing system will include many
of the components of a nanofactory. The design of a nanofactory likewise will
include components of a wide range of products. A project to achieve exponential
molecular manufacturing would not need much additional effort to prepare for
rapid creation of nanofactories and their highly advanced products.
Sudden availability of advanced products of all sizes in large quantity could
be highly disruptive. It would confer a large military advantage on whoever
got it first, even if only a few months ahead of the competition. This implies
that molecular manufacturing technology could be the focus of a high-stakes
arms race. Rapid design and production of products would upset traditional
manufacturing and distribution. Nanofactories would be simple enough to be
completely automated—and with components small enough that this would
be necessary. Complete automation implies that they will be self-contained
and easy to use. Nanofactory-built products, including nanofactories themselves,
could be as hard to regulate as Internet file-sharing. These and other problems
imply that wise policy, likely including some global-scale policy, will be
needed to deal with molecular manufacturing. But if it takes only months to
advance from 100-nanometer manufacturing systems to self-contained nanofactories
and easily-designed revolutionary products, there will not be time to make
wise policy once exponential manufacturing is achieved. We will have to start
ahead of time.
* * * * * * * * * * * * * * * *
FUNDRAISING ALERT!
Recent developments in efforts to roadmap the technological steps towards
molecular manufacturing make the work of CRN even more important.
It is critical that we examine the global implications of this rapidly emerging
technology, and CRN continues to be in the forefront of this discussion.
But we need to grow, and rapidly, to meet the expanding need.
Your donation to CRN will help us to achieve that growth. We rely largely
on individual donations and small grants for our survival.
To make a contribution on-line click
here. This is important work and we welcome your participation.
* * * * * * * * * * * * * * * *
C-R-Newsletter #30 May 11, 2005
CRN
goes to Minnesota
Moving
Closer to a Manufacturing Revolution
War,
Interdependence, and Nanotechnology
Nanotechnology
Research Discrepancy?
Responsible
Nanotechnology Report Issued
Reminder
about WFS Seminar & Conference
Feature
Essay: Molecular Manufacturing vs. Tiny Nanobots
CRN
Needs Your Help!
=========
As usual, things
are happening fast at CRN. We'll recap most of the highlights here—but
to keep up with us on a daily basis, be sure to check our Responsible
Nanotechnology weblog.
CRN
goes to Minnesota
Last week, CRN Director of Research Chris Phoenix, made a presentation at
a unique
new conference sponsored by the Society of Manufacturing Engineers (SME).
His talk, "Molecular Manufacturing: Beyond Nanomanufacturing," was based
on a 50-page paper (see below) prepared especially for this event.
As far as we know, this is the first meeting ever presented by and for the
manufacturing sector to focus specifically on what they can expect from advanced
nanotechnology. The one-day conference, called "Molecular Nanotechnology and
Manufacturing: The Enabling Tools and Applications," took place May 4 at the
Minneapolis Convention Center.
Moving Closer to a Manufacturing Revolution
Nanotechnology’s long-expected transformation of manufacturing has just
moved closer to reality. A new analysis of existing technological capabilities,
including proposed steps from today's nanotech to advanced molecular machine
systems, has been released by CRN.
The study, "Molecular Manufacturing: What, Why and How," was completed by
Chris Phoenix and is available
online at Wise-Nano.org. It shows how existing technologies can be coordinated
toward a reachable goal of general-purpose molecular manufacturing.
Chris describes two approaches for building the initial basic tools with current
technology. Other sections outline incremental improvement from those early
tools toward the first integrated nanofactory, and analyze a scalable architecture
for a more advanced nanofactory. Product performance and likely applications
are discussed, as well as incentives for corporate or government investment
in the technology. Finally, considerations and recommendations for a targeted
development program are presented.
War, Interdependence, and Nanotechnology
From the dawn of the nuclear age until the present day, we have relied on
two mechanisms to protect us from World War III: the doctrine of Mutually
Assured Destruction (MAD), and the growing interdependence of nations. In
the very near future, we may not be able to count on these controls. The tenuous
balance of MAD and the worldwide network of commercial trade are both threatened
by the rise of advanced nanotechnology.
"War,
Interdependence, and Nanotechnology" is the title of a new essay from
CRN Executive Director Mike Treder, published recently by Future Brief.
The essay ends with a warning that the disruptive and destabilizing implications
of advanced nanotechnology must not be underestimated. This is balanced,
however, with recommendation for studies that may allow many of the near
miraculous benefits to be realized without the worst-case disasters occurring.
Nanotechnology Research Discrepancy?
An important
editorial in the current issue of The New Atlantis describes
what they see as a "discrepancy between what Congress expects [from nanotechnology
research] and what federal funds in fact support."
In reviewing the activities of a National Research Council committee tasked
to evaluate the goals
and progress of the U.S. National Nanotechnology Initiative, the editorial
says...
It is our hope that the committee will offer a clear analysis of the technical potential of molecular manufacturing, and a clear recommendation on whether federal nanotechnology funds should be allocated toward theoretical and practical research into molecular manufacturing.
CRN
believes that any serious, unbiased investigation into the steps
required to move from today's nanoscale technologies to exponential
general-purpose molecular manufacturing will conclude that the matter
raises serious implications, and that actions heretofore ignored should
be undertaken with urgency. By that, we mean a well-funded, dedicated
program of inquiry something like our Thirty
Essential Studies.
We hope the NRC committee will agree, and that their recommendation will spur
similar—or, better yet, coordinated—actions from other major governmental
and civil society organizations around the world.
Responsible Nanotechnology Report Issued
CRN's quarterly Responsible Nanotechnology Report has been delivered
to members of the C-R-Network.
Interested parties from 19 nations on six different continents received the
report. Some of the countries include: Argentina, Australia, Belgium, Czech
Republic, Egypt, Finland, France, India, Iran, Ireland, Nigeria, Russian Federation,
Singapore, Taiwan, Thailand, and others, including the U.S., Canada, and the
U.K.
If you would like to receive our quarterly report—in print, via email,
or both—just sign up for the C-R-Network.
It's free, and we welcome everyone's participation.
Reminder about WFS Seminar & Conference
In connection with their hugely popular annual conference, the World Future
Society has announced "an exploration series designed to provide an outline
of several critical new fields with the potential for significant impact on
the social, economic, and cultural fabric of modern society." For this year,
they have organized a Symposium
on Nanotechnology (PDF), which CRN’s Mike Treder will assist in
presenting. It’s happening in Chicago on July 29, 2005. Hope to see
you there!
Feature Essay: Molecular Manufacturing
vs. Tiny Nanobots
Chris Phoenix, Director of Research, Center for Responsible Nanotechnology
A few days ago, a high-ranking official of the National Nanotechnology Initiative
told me that statements against "nanobots" on their website had been intended
to argue against three-nanometer devices that could build anything.
This is frustrating, because no one has proposed such devices.
A three-nanometer cube would contain a few thousand atoms. This is about the
right size for a single component, such as a switch or gear. No one has suggested
building an entire robot in such a tiny volume. Even ribosomes, the protein-constructing
machinery of cells, are more like 30 nanometers. A mechanical molecular fabrication
system might be closer to 100 or 200 nanometers. That's still small enough
to be built molecule-by-molecule in a few seconds, but large enough to contain
thousands or millions of components.
Nanosystems a few hundred nanometers in size are convenient for several other
reasons. They are small enough to be built error-free, and remain error-free
for months or years despite background radiation. They are large enough to
be handled mechanically with high efficiency and speed. They are smaller than
a human cell. They are large enough to contain a complete CPU or other useful
package of equipment. So it seems likely that designs for molecular manufacturing
products and nanofactories will be based on components of this size.
So much for size. Let's look at the other half of that strawman, the part
about "could build anything." There has been a persistent idea that molecular
manufacturing proposes, and depends on, devices that can build any desired
molecule. In fact, such devices have never been proposed. The idea probably
comes from a misinterpretation of a section heading in Drexler's early book Engines
of Creation.
The section
in question talked about designing and building a variety of special-purpose
devices to build special molecular structures: "Able to tolerate acid or
vacuum, freezing or baking, depending on design, enzyme-like second-generation
machines will be able to use as 'tools' almost any of the reactive molecules
used by chemists -- but they will wield them with the precision of programmed
machines. They will be able to bond atoms together in virtually any stable
pattern, adding a few at a time to the surface of a workpiece until a complex
structure is complete. Think of such nanomachines as assemblers."
Unfortunately, the section was titled "Universal Assemblers." This was misread
as referring to a single "universal" assembler, rather than a collective capability
of a large number of special-purpose machines. But there is not, and never
was, any proposal for a single universal assembler. The phrase has always
been plural.
The development of molecular manufacturing theory has in fact moved in the
opposite direction. Instead of planning for systems that can do a very broad
range of molecular fabrication, the latest designs aim to do just a few reactions.
This will make it easier to develop the reactions and analyze the resulting
structures.
Another persistent but incorrect idea that has attached itself to molecular
manufacturing is the concept of "disassemblers." According to popular belief,
tiny nanomachines will be able to take apart anything and turn it into raw
materials. In fact, disassemblers, as described
in Engines, have a far more mundane purpose: "Assemblers will
help engineers synthesize things; their relatives, disassemblers, will help
scientists and engineers analyze things." In other words, disassemblers
are a research tool, not a source of feedstock.
Without universal assemblers and disassemblers, molecular manufacturing is
actually pretty simple. Manufacturing systems built on a 100-nanometer scale
would convert simple molecular feedstock into machine parts with fairly simple
molecular structure—but, just as simple bricks can be used to build
a wide variety of buildings, the simple molecular structure could serve as
a backbone for rather intricate shapes. The manufacturing systems as well
as their products would be built out of modules a few hundred nanometers in
size. These modules would be fastened together to make large systems.
As I explained in my recent 50-page paper, "Molecular
Manufacturing: What, Why, and How," recent advances in theory have shown
that a planar layout for a nanofactory system can be scaled to any size,
producing about a kilogram per square meter per hour. Since the factory
would weigh about a kilogram per square meter, and could build a larger
factory by extruding it edgewise, manufacturing capacity can be doubled
and redoubled as often as desired. The implications of non-scarce and portable
manufacturing capacity, as well as the high performance, rapid fabrication,
and low cost of the products, are far beyond the scope of this essay. In
fact, studying and preparing for these implications is the reason that CRN
exists.
* * * * * * * * * * * * * * *
CRN NEEDS YOUR HELP!
Since our founding two years ago, the Center
for Responsible Nanotechnology has accomplished a great deal. We have
published research papers, spoken at conferences, sent out press releases,
and created a sizable presence on the web. As a result of these efforts,
we have seen a considerable increase in awareness of the implications
of advanced nanotechnology. This is vital work that few others are doing,
despite its critical importance.
Unfortunately, we’re near the end of our current funding stream and
virtually operating out of our own pockets. Unless we can quickly raise
the funds necessary to support our growth, CRN's work will be severely hindered.
If we are to continue, we need to aggressively seek other sources of funding,
and that includes contributions from committed individuals such as yourself.
Please consider making a generous contribution to CRN. Your help, in any
amount, will make a real difference to us in building the organization and
continuing to inspire meaningful dialogue about our future in a world where molecular
manufacturing is a reality.
To make a tax-deductible contribution by credit card, please click
here.
OR…you can mail a check, made out to "CRN/World Care" and addressed
to:
CRN/World Care
PO Box 64001
Tucson, AZ 85728
Many thanks in advance for all the help you can give! Please feel free to contact us if you have any questions.
We sincerely appreciate the people who already have donated. You are truly making the world a better and safer place.
* * * * * * * * * * * * * * *
C-R-Newsletter #29 April 14, 2005
New
Research on DNA
Molecular
Manufacturing, Step by Step
Nanotech
High Beams
Information
Week does CRN
Chris
Phoenix Interviewed
Military
Uses of Nanotechnology
CRN
goes to San Diego
CRN
goes to Minneapolis
Feature
Essay: Protein Springs and Tattoo Needles—Work in progress
at CRN
CRN
Needs Your Help!
=========
It's been an extraordinarily
busy and exciting month for CRN. We'll recap most of the highlights here—but
to keep up with us on a daily basis, be sure to check our Responsible
Nanotechnology weblog.
New
Research on DNA
Inspired by one of CRN's Thirty
Essential Studies — Study
#10, "What will be required to develop nucleic acid manufacturing
and products?" — researcher Frank Boehm wrote "An Investigation
of Nucleic Acid/DNA-Based Manufacturing." In a 26-page paper with 242
references, published
online this month at the Wise-Nano.org website, Boehm describes
many different kinds of tools in the DNA device toolbox, and shows how
rapidly development is occurring in this field.
Molecular Manufacturing, Step by Step
Advanced nanotechnology—molecular
manufacturing—will bring benefits and risks, both on an unprecedented
scale. A new
paper by Chris Phoenix, CRN's Director
of Research, suggests that development of molecular manufacturing
can be an incremental process from today's capabilities, and may not
be as distant as many believe.
Three stages for the development of molecular manufacturing, each with specific
milestones, are identified in the paper. The first stage is the computer-controlled
fabrication of precise molecular structures. The second stage uses nanoscale
tools to build more tools, enabling exponential growth of the manufacturing
base. The third stage, which integrates nanoscale products into large structures,
leads directly to desktop "nanofactories" that
could build advanced products.
Nanotech High Beams
It’s as if we’re driving very fast, into pitch-black
darkness, moving rapidly into uncharted territory… That's
the state of nanotechnology today, argues CRN Executive Director Mike
Treder in an
essay published this month by Future Brief. The world's
current lack of preparedness for the disruptive consequences of
molecular manufacturing can only be redressed if we turn on the "high
beams" and look further ahead. Examining the health and safety risks
of current nanoscale technologies is necessary, but it is hardly
sufficient.
Information Week does
CRN
In March, Information Week published a news
article about the "desktop nanofabrication system" (nanofactory)
proposed by CRN's Chris Phoenix. The author, Chappell Brown, appropriately
distinguished between the original
vision of nanotechnology, and the relatively mundane—although
highly useful—work being carried out today. The same story
also appeared in EE Times. As a result of Brown's article,
CRN's daily web traffic almost doubled.
Chris
Phoenix Interviewed
In an in-depth
interview published last month by nanomagazine, Chris answered
many questions regarding nanofactory feasibility
and the challenges
that remain to develop the technology. This was actually the second
segment of a long two-part interview; the first part is here.
Thanks go to Sander Olson for his insightful questions and for publishing
the full interview.
Military
Uses of Nanotechnology
The final results of a six-month long study conducted by the people who run
the Millennium
Project of the American Council for the United Nations University were
published last month. Two topics were covered: "Potential Environmental
Pollution and Health Hazards Resulting from Possible Military Uses of Nanotechnology," and "Implications
for Research Priorities Helpful to Prevent and/or Reduce Such Pollution
and Hazards." An expert panel of 29 participants—including representation
from CRN—identified potential military uses of nanotechnology that
might occur between 2005–2010 and 2010–2025, and suggested research
questions whose answers might produce knowledge to help prevent or reduce
the health and environmental hazards. More details on the survey are available here.
CRN goes to San Diego
Mike was invited to make a presentation during a special "Nanotechnology and
the Environment" symposium held in San Diego last month during the annual
meeting of the American
Chemical Society. Other speakers on the program were John Balbus of Environmental
Defense, Christine Peterson of the Foresight
Institute, and Alexis Vlandas of the International
Network of Scientists and Engineers for Global Responsibility.
The session was expertly organized by Barbara Karn and Nora Savage
of the U.S. Environmental
Protection Agency. A large audience seemed genuinely interested
in what was presented and asked numerous questions about the longer-term
implications of molecular
manufacturing.
CRN goes to Minneapolis
Chris is scheduled to give a presentation next month at a conference sponsored
by the Society of Manufacturing Engineers (SME). His talk, "Molecular Manufacturing:
Beyond Nanomanufacturing," is based on a 50-page paper he has written especially
for this conference, and which will be published in the official journal of
conference proceedings. The one-day conference is called "Molecular Nanotechnology
and Manufacturing: The Enabling Tools and Applications," and will take place
at the Minneapolis Convention Center on May 4.
Feature Essay: Protein Springs and Tattoo Needles—Work in progress at
CRN
Chris Phoenix, Director of Research, Center for Responsible Nanotechnology
This month's science essay will be a little different. Rather than explaining
how a known aspect of the nanoscale works, I'll provide a description of my
recent research activities and scientific thinking. I'll explain what the
ideas are, where the inspirations came from, and what they might mean. This
is a view "behind the scenes" of CRN. As always, I welcome comments and
questions.
=========
I'm currently investigating two topics. One is how to make the simplest possible
nanoscale molecular manufacturing system. I think I've devised a version that
can be developed with today's technology, but can be improved incrementally
to approach the tabletop diamondoid nanofactory that is the major milestone
of molecular manufacturing. The other topic is how proteins work. I think
I've had an insight that solves a major mystery: how protein machines can
be so efficient. And if I'm right, it means that natural protein machines
have inherent performance limitations relative to artificial machines.
I'll talk about the proteins first. Natural proteins can do things that we
can't yet even begin to design into artificial proteins. And although we can
imagine and even design machines that do equivalent functions using other
materials, we can't build them yet. Although I personally don't expect proteins
to be on the critical path to molecular manufacturing, some very smart people
do, both within and outside the molecular manufacturing community. And in
any case, I want to know how everything at the nanoscale works.
One of the major questions about protein machines is how they can be so efficient.
Some of them, like ATP synthase, are nearly 100% efficient. ATP synthase has
a fairly complex job: it has to move protons through a membrane, while simultaneously
converting molecules of ADP to ATP. That's a pump and an enzyme-style chemical
reaction--very different kinds of operation--linked together through a knobby
floppy molecule, yet the system wastes almost no energy as it transfers forces
and manipulates chemicals. A puzzle, to be sure: how can something like a
twisted-up necklace of different-sized soft rubber balls be the building material
for a highly sophisticated machine?
I've been thinking about that in the back of my mind for a few months. I do
that a lot: file some interesting problem, and wait for some other random
idea to come along and provide a seed of insight. This time, it worked. I
have been thinking recently about entropy and springiness, and I've also been
thinking about what makes a nanoscale machine efficient. And suddenly it all
came together.
A nanoscale machine is efficient if its energy is balanced at each point in
its action. In other words, if a motion is "downhill" (the machine has less
energy at the end of the motion) then that energy must be transferred to something
that can store it, or else it will be lost as heat. If a motion is "uphill" (requires
energy) then that energy must be supplied from outside the machine. So a machine
with large uphills and downhills in its energy-vs.-position trajectory will
require a lot of power for the uphills, and will waste it on the downhills.
A machine with sufficiently small uphills and downhills can be moved back
and forth by random thermal motion, and in fact, many protein machines are
moved this way.
A month or so ago, I read an article on ATP synthase in which the researchers
claimed that the force must be constant over the trajectory, or the machine
couldn't be efficient. I thought about it until I realized why this was true.
So the question to be answered was, how was the force so perfectly balanced?
I knew that proteins wiggled and rearranged quite a bit as they worked. How
could such a seemingly ad-hoc system be perfectly balanced at each point along
its trajectory?
As I said, I have been thinking recently about entropic springs. Entropy,
in this application, means that nanoscale objects (including molecular fragments)
like to have freedom to wiggle. A stringy molecule that is stretched straight
will not be able to wiggle. Conversely, given some slack, the molecule will
coil and twist. The more slack it has, the more different ways it can twist,
and the happier it will be. Constraining these entropic wiggles, by stretching
a string or squashing a blob, costs energy. At the molecular scale, this effect
is large; it turns out that entropic springiness, and not covalent bond forces,
is the main reason why latex rubber is springy. This means that any nanoscale
wiggly thing can function as an entropic spring. I sometimes picture it as
a tumbleweed with springy branches--except that there is only one object (for
example, a stringy molecule) that wiggles randomly into all the different
branch positions. Sometimes I compare it to a springy cotton ball.
One Saturday morning I happened to be thinking simultaneously about writhing
proteins, entropic springs, and efficient machines. I suddenly realized, as
I thought about the innards of a protein rearranging themselves like a nest
of snakes, that installing lots of entropic springs in the middle of that
complex environment would provide lots of adjustable parameters to balance
whatever force the machine's function generated. Because of the complex structural
rearrangement of the protein, each spring would affect a different fraction
of the range of motion. Any uphills and downhills in its energy could be smoothed
out.
Natural protein machines are covered and filled with floppy bits that have
no obvious structural purpose. However, each of those bits is an entropic
spring. As the machine twists and deforms, its various springs are compressed
or allowed to expand. An entropic spring only has to be attached at one point;
it will press against any surface that happens to come into its range. Compressing
the spring takes energy and requires force; releasing the spring will recover
the energy, driving the machine forward.
As soon as I had that picture, I realized that each entropic spring could
be changed independently, by blind evolution. By simply changing the size
of the molecule, its springiness would be modified. If a change in a spring
increased the efficiency of the machine, it would be kept. The interior reconfiguration
of proteins would provide plenty of different environments for the springs--plenty
of different variables for evolution to tweak.
Always before, when I had thought about trying to design a protein for efficiency
and effectiveness, I had thought about its backbone--the molecular chain that
folds up to form the structure. This is large, clumsy, and soft--not suitable
for implementing subtle energy balancing. It would be very hard (no pun intended)
to design a system of trusses, using protein backbones and their folded structure,
that could implement the right stiffness and springiness to balance the energy
in a complex trajectory. But the protein's backbone has lots of dangling bits
attached. The realization that each of those was an entropic spring, and each
could be individually tuned to adjust the protein's energy at a different
position, made the design task suddenly seem easy.
The task could be approached as: 1) Build a structure to perform the protein's
function without worrying about efficiency and energy balance. Make it a large
structure with a fair amount of internal reconfiguration (different parts
having different relative orientations at different points in the machine's
motion); 2) Attach lots of entropic springs all over the structure; 3) Tune
the springs by trial and error until the machine is efficient--until the energy
stored by pressure on the myriad springs exactly balances the energy fluctuations
that result from the machine's functioning.
I proposed this idea to a couple of expert nanoscale scientists--a molecular
manufacturing theorist and a physicist. And I learned a lot. One of the experts
said that he had not previously seen the observation that adding lots of springs
made it easier to fine-tune the energy accurately. That was pretty exciting.
I learned that proteins do not usually disfigure themselves wildly during
their operation--interior parts usually just slip past each other a bit. I
watched some movies of proteins in action, and saw that they still seemed
to have enough internal structural variation to cause different springs to
affect different regions of the motion trajectory. So, that part of the idea
still seems right.
I had originally been thinking in terms of the need to balance forces; I learned
that energy is a slightly more general way to think about the problem. But
in systems like these, force is a simple function of energy, and my theory
translated perfectly well into a viewpoint in terms of energy. It turned out
that one of my experts had studied genetic algorithms, and he warned that
there is no benefit to increasing the number of evolvable variables in the
system if the number of constraints increases by the same number. I hadn't
expected that, and it will take more theoretical work to verify that adding
extra structures in order to stick more entropic springs on them is not a
zero-sum game. But my preliminary thinking says that one piece of structure
can have lots of springs, so adding extra structures is still a win.
The other expert, the physicist, asked me how much of the effect comes from
entropic springiness vs. mechanical springiness. That's a very good question.
I realized that there is a measurable difference between entropic springs
and mechanical (covalent bond) springs: the energy stored by an entropic spring
is directly proportional to the temperature. If a machine's efficiency depends
on fine-tuning of entropic springs, then changing the temperature should change
all the spring constants and destroy the delicate energy balance that makes
it efficient. I made the prediction, therefore, that protein machines would
have a narrow temperature range in which they would be efficient. Then I thought
a bit more and modified this. A machine could use a big entropic spring as
a thermostat, forcing itself into different internal configurations at each
temperature, and fine-tuning each configuration separately. This means that
a machine with temperature-sensitive springs could evolve to be insensitive
to temperature. But a machine that evolved at a constant temperature, without
this evolutionary pressure, should be quite sensitive to temperature.
After thinking this through, I did a quick web search for the effect of temperature
on protein activity. I quickly found a
page containing a sketch of enzyme activity vs. temperature for various
enzymes. Guess what--the enzyme representing Arctic shrimp has maximum activity
around 4 C, and mostly stops working just a few degrees higher. That looks
like confirmation of my theory.
That web page, as well as another one, says that enzymes stop working at elevated
temperatures due to denaturation--change in three-dimensional structure
brought on by breaking of weak bonds in the protein. The other
web page also asserts that the rate of enzyme activity, "like all reactions," is
governed by the Arrhenius equation, at least up to the point where the enzyme
starts to denature. The Arrhenius equation says that if an action requires
thermal motion to jump across an energy barrier, the rate of the action
increases as a simple exponential function of temperature. But this assumes
that the height of the barrier is not dependent on temperature. If the maintenance
of a constant energy level (low barriers) over the range of the enzyme's
motion requires finely tuned, temperature dependent mechanisms, then spoiling
the tuning--by a temperature change in either direction--will decrease the
enzyme's rate.
I'll go out on a limb and make a testable prediction. I predict that many
enzymes that are evolved for operation in constant or nearly constant temperature
will have rapid decrease of activity at higher and lower temperatures, even
without structural changes. When the physical structure of some of these supposedly
denatured enzymes is examined, it will be found that the enzyme is not in
fact denatured: its physical structure will be largely unchanged. What will
be changed is the springiness of its entropic springs.
If I am right about this, there are several consequences. First, it appears
that the design of efficient protein machines may be easier than is currently
believed. There's no need to design a finely-tuned structure (backbone). Design
a structure that barely works, fill it with entropic springs, and fine-tune
the springs by simple evolution. Analysis of existing proteins may also become
easier. The Arrhenius equation should not apply to a protein that uses entropic
springs for energy balancing. If Arrhenius is being misapplied, then permission
to stop using it and fudging numbers to fit around it should make protein
function easier to analyze. (The fact that 'everyone knows' Arrhenius applies
indicates that, if I am right about entropic springs being used to balance
energy, I've probably discovered something new.)
Second, it may imply that much of the size and intricate reconfiguration of
protein machines exists simply to provide space for enough entropic springs
to allow evolutionary fine-tuning of the system. An engineered system made
of stiff materials could perform an equivalent function with equivalent efficiency
by using a much simpler method of force/energy compensation. For example,
linking an unbalanced system to an engineered cam that moves relative to a
mechanical spring will work just fine. The compression of the spring, and
the height of the cam, will correspond directly to the energy being stored,
so the energy required to balance the machine will directly specify the physical
parameters of the cam.
The third consequence, if it turns out that protein machines depend on entropic
springs, is that their speed will be limited. To be properly springy, an entropic
spring has to equalize with its space; it has to have time to spread out and
explore its range of motion. If the machine is moved too quickly, its springs
will lose their springiness and will no longer compensate for the forces;
the machine will become rapidly less efficient. Stiff mechanical springs,
having fewer low-frequency degrees of freedom, can equilibrate much faster.
If I understand correctly, my physics expert says that a typical small entropic
spring can equilibrate in fractions of a microsecond. But stiff mechanical
nanoscale springs can equilibrate in fractions of a nanosecond.
I will continue researching this. If my idea turns out to be wrong, then I
will post a correction notice in our newsletter archive at the top of this
article, and a retraction in the next newsletter. But if my idea is right,
then it appears that natural protein machines must have substantially lower
speeds than engineered nanoscale machines can achieve with the same efficiency. "Soft" and "hard" machines
do indeed work differently, and the "hard" machines are simply better.
=========
The second thing I am investigating is the design of a nanoscale molecular
manufacturing system that is simple enough to be developed today, but functional
enough to build rapidly improving versions and large-throughput arrays.
It may seem odd, given the ominous things CRN has said about the dangers of
advanced molecular manufacturing, that I am working on something that could
accelerate it. But there's a method to my madness. Our overall goal is not
to retard molecular manufacturing; rather, it is to maximize the amount of
thought and preparation that is done before it is developed. Currently,
many people think molecular manufacturing is impossible, or at least extremely
difficult, and will not even start being developed for many years. But we
believe that this is not true--we’re concerned that a small group of
smart people could figure out ways to develop basic
capabilities fairly quickly.
The primary insights of molecular manufacturing--that stiff molecules make
good building blocks, that nanoscale machines can have extremely high performance,
and that general-purpose manufacturing enables rapid development of better
manufacturing systems--have been published for decades. Once even a few people
understand what can be done with even basic capabilities, we think they will
start working to develop them. If most people do not understand the implications,
they will be unprepared. By developing and publishing ways to develop molecular
manufacturing more easily, I may hasten its development, but I also expect
to improve general awareness that such development is possible and may happen surprisingly
soon. This is a necessary precondition for preparedness.
That's why I spend a lot of my time trying to identify ways to develop molecular
manufacturing more easily.
An early goal of molecular manufacturing is to build a nanoscale machine that
can be used to build more copies and better versions. This would answer nagging
worries about the ability of molecular manufacturing systems to make large
amounts of product, and would also enable rapid development of molecular manufacturing
technologies leading to advanced nanofactories.
I've been looking for ways to simplify the Burch/Drexler planar
assembly nanofactory. This method of "working backward" can be useful
for planning a development pathway. If you set a plausible goal pretty far
out, and then break it down into simpler steps until you get to something
you can do today, then the sequence of plans forms a roadmap for how to
get from today's capabilities to the end goal.
The first simplification I thought of was to have the factory place blocks
that were built externally, rather than requiring it to manufacture the blocks
internally. If the blocks can be prefabricated, then all the factory has to
do is grab them and place them into the product in specified locations.
I went looking for ways to join prefabricated molecular blocks and found a
possible solution. A couple of amino acids, cysteine and histidine, like to
bind to zinc. If two of them are hooked to each block, with a zinc ion in
the middle, they'll form a bond quite a bit stronger than a hydrogen bond.
That seems useful, as long as you can keep the blocks from joining prematurely
into a random lump. But you can do that simply by keeping zinc away.
So, mix up a feedstock with lots of molecular zinc-binding building blocks,
but no zinc. Build a smart membrane with precisely spaced actuators in it
that can transport blocks through the membrane. On one side of the membrane,
put the feedstock solution. On the other side of the membrane, put a solution
of zinc, and the product. As the blocks come through the membrane one at a
time, they join up with the zinc and become "sticky"--but the mechanism can
be used to retain them and force them into the right place in the product.
It shouldn't require a very complex mechanism to "grab" blocks from feedstock
(via Brownian assembly) through a hole in a membrane, move them a few nanometers
to face the product, and stick them in place. In fact, it should be possible
to do this with just one molecular actuator per position. A larger actuator
can be used to move the whole network around.
Then I thought back to some stuff I knew about how to keep blocks from clumping
together in solution. If you put a charge on the blocks, they will attract
a "screen" of counterions, and will not easily bump each other. So, it might
be possible to keep blocks apart even if they would stick if they ever bumped
into each other. In fact, it might be very simple. A zinc-binding attachment
has four amino acids per zinc, two on each side. Zinc has a +2 charge. If
the rest of the block has a -1 charge for every pair of amino acids, then
when the block is bound with zinc into a product, all the charges will match
up. But if it's floating in solution with zinc, then the zinc will still be
attracted to the two amino acids; in this case, the block should have a positive
charge, since each block will have twice as much zinc-charge associated with
it in solution as when it's fastened into the product. This might be enough
to keep blocks from getting close enough to bind together. But if blocks were
physically pushed together, then the extra zinc would be squeezed out, and
the blocks would bind into a very stable structure.
That's the theory, at this point. It implies that you don't need a membrane,
just something like a tattoo needle that attaches blocks from solution and
physically pushes them into the product. I do not know yet whether this will
work. I will be proposing to investigate this as part of a Phase 2 NIAC project.
If the theory doesn't work, there are several other ways to fasten blocks,
some triggered by light, some by pressure, and some simply by being held in
place for a long enough period of time.
It appears, then, that the simplest way to build a molecular manufacturing
system may be to develop a set of molecular blocks that will float separately
in solution but fasten together when pushed. At first, use a single kind of
block, containing a fluorescent particle. Use a scanning probe microscope
to push the blocks together. (You can scan the structure with the scanning
probe microscope, or see the cluster of fluorescence with an ordinary light
microscope.) Once you can build structures this way, build a structure that
will perform the same function of grabbing blocks and holding them to be pushed
into a product. Attach that structure to a nano-manipulator and use it to
build more structures. You'd have a hard time finding the second-level structures
with a scanning probe microscope, but again the cluster of fluorescence should
show up just fine in a light microscope.
Once you know you can build a passive structure that builds structures when
poked at a surface, the next step is to build an active structure--including
an externally controlled nanoscale actuator--that builds structures. Use your
scanning probe microscope with multiple block types to build an actuator that
pushes its block forward. Build several of those in an array. Let them be
controlled independently. You still need a large manipulator to move the array
over the surface, but you can already start to increase your manufacturing
throughput. By designing new block types, and new patterns of attaching the
blocks together, better construction machines could be built. Sensors could
be added to detect whether a block has been placed correctly. Nanoscale digital
logic could be added to reduce the number of wires required to control the
system. And if anyone can get this far, there should be no shortage of ideas
and interest directed at getting farther.
=========
That's an inside look at how my thinking process works, how I develop ideas
and check them with other experts, and how what I'm working on fits in with
CRN's vision
and mission. Please contact
me if you have any feedback.
Chris
*
* * * * * * * * * * * * * *
CRN NEEDS YOUR HELP!
Since our founding two years ago, the Center
for Responsible Nanotechnology has accomplished a great deal. We have
published research papers, spoken at conferences, sent out press releases,
and created a sizable presence on the web. As a result of these efforts,
we have seen a considerable increase in awareness of the implications
of advanced nanotechnology. This is vital work that few others are doing,
despite its critical importance.
Unfortunately, we’re near the end of our current funding stream and
virtually operating out of our own pockets. Unless we can quickly raise
the funds necessary to support our growth, CRN's work will be severely hindered.
If we are to continue, we need to aggressively seek other sources of funding,
and that includes contributions from committed individuals such as you.
Please consider making a generous contribution to CRN. Your help, in any
amount, will make a real difference to us in building the organization and
continuing to inspire meaningful dialogue about our future in a world where molecular
manufacturing is a reality.
To make a tax-deductible contribution by credit card, please click
here. You
will be directed to World Care's page under "Network for Good." In
the Designation box, be sure to say that your donation is for CRN.
OR…you can mail a check, made out to "CRN/World Care" and addressed
to:
CRN/World Care
PO Box 64001
Tucson, AZ 85728
Many thanks in advance for all the help you can give! Please feel free to contact us if you have any questions.
* * * * * * * * * * * * * * *
C-R-Newsletter #28 March 10, 2005
CONTENTS
CRN
goes to Washington
CRN
goes to Italy
SciDev.net addresses
Nanotechnology
UK
Government responds to Royal Society
CRN
says "Nanobots Not Needed"
Talking
with Economists about Nanotechnology
Talking
with Chemists about Nanotechnology
Feature
Essay: Information Delivery for Nanoscale Construction
=========
CRN
goes to Washington
Last month (February 10-11), Chris Phoenix attended a two-day
workshop in Washington D.C. organized by the U.S. National
Academy of Sciences, and spoke on a panel of experts about the meaning
of and potential for molecular manufacturing. Chris also was asked to
prepare a series of briefing
papers for the NAS committee, which have since been posted on our
Responsible Nanotechnology weblog. The committee appeared to study the
matter with
an open mind, and we look forward to their first report to Congress
this summer.
CRN goes to Italy
While Chris was
in Washington, Mike Treder was in Trieste, Italy, taking part in an Expert
Group Meeting on "North-South Dialog on Nanotechnology: Challenges
and Opportunities." The meeting was organized by the International
Centre for Science and High Technology, an Institute of the United
Nations operating in the framework of the United
Nations Industrial Development Organization.
A total of eighty people from all around the world—scientists, academics,
government personnel, and NGO representatives—were gathered for this
event. Mike presented his ideas on "Creating Effective Public Policy for Managing
Advanced Nanotechnology," which was favorably received, although there were
differing points of view on the expected
time frame for development of molecular manufacturing. You can view
Mike's PowerPoint presentation here.
SciDev.net addresses Nanotechnology
The online news site SciDev.net recently posted a "Nanotechnology
Quick Guide," which includes an overview of both current nanoscale technologies
and the possibilities of advanced nanotechnology. One of the links they
provide is to CRN, and in fact, we were told by the Quick Guide’s
primary author, Catherine Brahic, that she used our material as a resource
for her writing.
SciDev.net also published an
editorial entitled "Helping the poor: the real challenge of nanotech," commenting
on the issues discussed at the Expert Group Meeting mentioned above.
UK
Government responds to Royal Society
In 2003, the British government asked the Royal
Society (somewhat equivalent to the U.S. National Academy of Sciences)
to undertake a study on "nanotechnology and the health and safety, environmental,
ethical and social issues that might stem from it." Their final
report was issued on July 29, 2004.
The UK government finally got around to responding to the report’s findings
just a few weeks ago, and no one, it seems, was pleased with what
they said. Professor Ann Dowling, chair of the working group that produced
the report, expressed
disappointment, as did scientist and blogger Richard
Jones, and eco-activist Jim
Thomas of the ETC Group. CRN also spoke
out about the government’s tepid response and the urgent
need for more serious
consideration of both the risks and benefits of nanotechnology.
CRN
says "Nanobots Not Needed"
The popular idea of so-called nanobots, powerful and at risk of running wild,
is not part of modern plans for building things "atom-by-atom" by molecular
manufacturing. Studies indicate that most people don't know the difference
between molecular manufacturing, nanoscale technology, and nanobots. Confusion
about terms, fueled by science fiction, has distorted the truth about advanced
nanotechnology. Nanobots are not needed for manufacturing, but continued misunderstanding
may hinder research into highly beneficial technologies and discussion of
the real dangers.
That's the summary of a new briefing
document prepared by CRN and provided primarily for journalists and
others who write or teach about nanotechnology.
As nanoscale technologies begin to move from the lab to the marketplace, and
attention turns to molecular
manufacturing research, it will be increasingly important to counter
outdated and incorrect ideas of nanotechnology and molecular manufacturing.
Both scientists and the public have gotten the idea that molecular manufacturing
requires the use of nanobots, and they may criticize or fear it on that
basis. The truth is less sensational, but its
implications are equally compelling.
Our statement stimulated lively discussion on the Foresight Institute's nanodot site, Howard
Lovy's blog, and the Google group sci.nanotech.
Talking
with Economists about Nanotechnology
Mike was asked to serve as moderator for a panel
discussion at the Eastern
Economic Association Annual Conference in New York City last week.
The panel was on "The Inevitability of BIG in a Robotic Future" (BIG is
Basic Income Guarantee). During discussion after the panelist's presentations,
the subject of economic disruption and other societal impacts resulting
from molecular manufacturing was raised. So Mike had the opportunity to
share some of CRN's concerns with a group of noted economists and sociologists.
Talking
with Chemists about Nanotechnology
We received a last-minute invitation to speak at a "Nanotechnology and the
Environment" symposium during the American
Chemical Society's 2005 annual meeting. Mike will travel to San Diego,
California, this weekend to deliver a short presentation on "the environmental,
human health and societal aspects of nanotechnology." It won't be easy to
adequately cover so many issues in a short address, but it's good to see
that the ACS is taking our point of view seriously.
Feature
Essay: Information Delivery for Nanoscale Construction
Chris Phoenix, Director of Research, CRN
A widely acknowledged goal of nanotechnology is
to build intricate, useful nanoscale structures. What usually goes unstated
is how the structures will be specified. Simple structures can be created
easily: a crystal is an atomically precise structure that can be created from
simple molecules and conditions. But complex nano-products will require some
way to deliver large quantities of information to the nanoscale.
A key indicator of a technology's usefulness is how fast it can deliver information.
A kilobyte is not very much information—less than a page of text or
a thumbnail image. A dialup modem connection can transfer several kilobytes
per second. Today's nanoscale manufacturing techniques can transfer at most
a few kilobytes per second. This will not be enough to make advanced products—only
simple materials or specialized components.
The amount of information needed to specify a product is not directly related
to the size of the product. A product containing repetitive structures only
needs enough information to specify one of the structures and control the
placement of the rest. The amount of information that needs to be delivered
also depends on whether the receiving machine must receive an individual instruction
for every operation, or whether it can carry out a sequence of operations
based on stored instructions. Thus, a primitive fabrication system may require
a gigabyte of information to place a million atoms, while a gigabyte may be
sufficient to specify a fairly simple kilogram-scale product built with an
advanced nanofactory.
There are several ways to deliver information to the nanoscale so as to construct
things. Information can either be encoded materially, in a stable pattern
of atoms or electrons, or it can be in an ephemeral form such as an electric
field, a pattern of light, a beam of charged particles, the position of a
scanning probe, or an environmental condition like temperature. The goal of
manufacturing is to embody the information, however it is delivered, into
a material product. As we will see, different forms of delivery have different
advantages and limitations.
Today's Techniques
To create a material pattern, it is tempting to start with materially encoded
information. This is what self-assembly does. A molecule can be made so that
it folds on itself or joins with others in quite intricate patterns. An example
of this that is well understood, and has already been used to make nanoscale
machines, is DNA. (See our previous science essay, "Nucleic
Acid Engineering.") Biology uses DNA mainly to store information, but
in the lab it has been used to make polyhedra, grid structures, and even
a programmable machine that can synthesize DNA strands.
One problem with self-assembly is that all the information in the final structure
must be encoded in the components. In order to make a complicated structure,
a lot of information must be programmed into the component molecules. There
are only a few ways to get information into molecules. One is to make the
molecules a piece at a time. In a long linear chain like DNA, this can be
done by repeating a few operations many times—specifically, by changing
the chemical environment in a way that adds one selected block to the chain
in each operation. (This can be viewed either as chemistry or as manufacturing.)
Automated machines exist that will do this by cycling chemicals through a
reactor, but they are relatively slow, and the process is expensive. The information
rate can be greatly increased by controlling the process with light; by shining
light in programmed sequence on different regions of a surface, DNA can be
grown in many different patterns in parallel. This can create a large “library” of
different DNA molecules with programmed sequences.
Another problem with self-assembly is that when the building blocks are mixed
together, it is hard to impose long-range order and to build heterogeneous
engineered structures. This limitation may be partially alleviated by providing
a large-scale template, either a material structure or an ephemeral spatial
pattern. Adding building blocks in a programmed sequence rather than mixing
them all together all at once also may help. A combination of massively parallel
programmable molecule synthesis and templated or sequenced self-assembly may
be able to deliver kilobytes per second of information to the nanoscale.
A theoretical possibility should be mentioned here. Information can be created
by starting with a lot of random codes, throwing away all the ones that don't
work, and duplicating the ones that do. One problem with this is that for
all but the simplest criteria, it will be too difficult and time-consuming
to implement tests for the desired functionality. Another problem is that
evolved solutions will require extra work to characterize, and unless characterized,
they will be hard to integrate into engineered systems. Although evolution
can produce systems of great subtlety and complexity, it is probably not suitable
for producing easily characterized general-purpose functional modules. Specific
molecular bio-designs such as molecular motors may be worth characterizing
and using, but this will not help with the problem of controlling the construction
of large, heterogeneous, information-rich products.
Optical lithography of semiconductors now has the capability to generate nanoscale
structures. This technique creates a pattern of light using a mask. The light
causes chemical changes in a thin surface layer; these changes can then be
used to pattern a substrate by controlling the deposition or removal of material.
One drawback of this approach is that it is not atomically precise, since
the pattern of light is far too coarse to resolve individual atoms. Another
drawback is that the masks are pre-built in a slow and very expensive process.
A computer chip may embody billions of bytes of information, but the masks
may take weeks to make and use; again, this limits the data rate to kilobytes
per second. There has been recent talk of using MEMS (micro electro mechanical
systems) technology to build programmable masks; if this works out, it could
greatly increase the data rate.
Several tools can modify single points in serial fashion with atomic or near-atomic
resolution. These include scanning probe microscopes and beams of charged
particles. A scanning probe microscope uses a large but sensitive positioning
and feedback system to bring a nanoscale point into controlled physical contact
with the surface. Several thousand pixels can be imaged per second, so in
theory an automated system could deliver kilobytes per second of changes to
the surface. An electron beam or ion beam can be steered electronically, so
it can be relatively fast. But the beam is not as precise as a scanning probe
can be, and must work in vacuum. The beam can be used either to remove material,
to chemically transform it, or to deposit any of several materials from low-pressure
gas. It takes a fraction of a millisecond to make a shallow feature at a chosen
point. Again, the information delivery rate is kilobytes per second.
Nanoscale Tools
To deliver information at a higher rate and use the information for more precise
construction, new technology will be required. In most of the techniques surveyed
above, the nanoscale matter is inert and is acted on by outside forces (ephemeral
information) created by large machines. In self-assembly, the construction
material itself encodes static patterns of information—which probably
were created by large machines doing chemistry. By contrast, nanoscale tools,
converting ephemeral information to concrete operations, could substantially
improve the delivery rate of information for nanoscale construction. Large
tools acting on inert nanoscale objects could never come close to the data
rates that are theoretically possible with nanoscale tools.
One reason why nanoscale tools are better is that they can move faster. To
a first approximation, the operating frequency of a tool increases in direct
proportion as its linear size shrinks. A 100-nm tool should be about a million
times faster than a 10-cm tool.
The next question is how the information will be delivered. There are several
candidates for really fast information delivery. Light can be switched on
and off very rapidly, but is difficult to focus tightly. Another problem is
that absorption of light is probabilistic, so a lot of light would have to
be used for reliable information delivery. Perhaps surprisingly, mechanical
signals may be useful; megahertz vibrations and pressure waves can be sent
over useful distances. Electrical signals can be sent along nanoscale wires
so that multiple independent signals could be delivered to each tool. In principle,
the mechanical and electrical portions of the system could be synchronized
for high efficiency.
Nanoscale computing elements can help with information handling in two ways.
First, they can split up a broadcast signal, allowing several machines receiving
the same signal to operate independently. This can reduce the complexity of
the macro-to-nano interface. Second, nanoscale computation can be used to
implement some kinds of error handling at a local level.
A final advantage of nanoscale tools, at least the subset of tools built from
molecules, is that they can be very precise. Precision is a serious problem
in micron-sized tools. A structure built by lithography looks like it has
been whittled with a pocket knife—the edges are quite ragged. This has
made it very difficult to build complex, useful mechanical devices at the
micron scale using lithography. Fortunately, things get precise again at the
very bottom, because atoms are discrete and identical. Small and simple molecular
tools have been built, and work is ongoing to build larger and more integrated
systems. The structural precision of molecular tools promises several advantages,
including predictable properties and low-friction interfaces.
Several approaches could be used, perhaps in combination, to build a nanoscale
fabrication system. If a simple and repetitive system can be useful, then
self-assembly might be used to build it. A repetitive system, once fabricated,
might be made less repetitive (programmed heterogeneously) by spatial patterns
such as an array of light. If it contains certain kinds of electronics, then
signals could be sent in to uniquely reconfigure the circuitry in each repeating
sub-pattern.
Of course, the point of the fabrication system is to build stuff, and a particularly
interesting kind of system is one that can build larger or better fabrication
systems. With information supplied from outside, a manufacturing system of
this sort could build a larger and more complex version of itself. This approach
is one of the goals of molecular manufacturing. It would allow the first tiny
system to be built by a very expensive or non-scalable method, and then that
tiny system can build larger ones, rapidly scaling upward and drastically
reducing cost. Or if the initial system was built by self-assembly, then subsequent
systems could be more complex than self-assembly could easily achieve.
The design of even a tabletop general-purpose manufacturing system could be
relatively simple, heterogeneous but hierarchical and repetitive. Once the
basic capabilities of nanoscale actuation, computation, and fabrication are
achieved in a way that can be engineered and recombined, it may not take too
long to start developing nanoscale tools that can do this in parallel, using
computer-supplied blueprints to build larger manufacturing systems and a broad
range of products.
C-R-Newsletter #27 February 3, 2005
CONTENTS
NAS
Workshop
Expert
Group Meeting
Network
Activity Coordinator
Events
Coordinator
Nano-Workshops
Symposium
on Nanotechnology
New
Paper Posted
Feature
Essay: What Is Molecular Manufacturing?
=========
NAS Workshop
As part of the U.S. 21st
Century Nanotechnology Research and Development Act (PDF), passed by
Congress and signed into law by the President in December 2003, the National
Academy of Sciences is required to "organize a workshop to study the technical
feasibility of molecular self-assembly for the manufacture of materials
and devices at the molecular scale."
That workshop is being held in Washington DC February 10-11, 2005. CRN’s
Chris Phoenix has been appointed to a panel of experts that will address the NAS
committee, and he will attend the entire workshop.
Expert Group Meeting
At the same time that Chris is in Washington, Mike Treder will be in Trieste,
Italy, to take part in an Expert
Group Meeting on "North-South dialog on nanotechnology: challenges and
opportunities." The meeting is organized by the International
Centre for Science and High Technology, an Institute of the United
Nations operating in the framework of the United
Nations Industrial Development Organization. This is quite an honor,
and we are pleased to have the opportunity to contribute.
Network Activity Coordinator
We are pleased to announce the appointment of Martin Coppa to the position
of CRN Network
Activity Coordinator. In this volunteer role, he will promote opportunities
for student
research collaborations within educational networks, maintain up-to-date
records of C-R-Network membership,
and coordinate communication with Network members.
Martin, who lives in San Francisco, is an undergraduate student majoring in
chemical engineering. Along with interests in the scientific development of
nanotechnology and specifically molecular manufacturing (MM), he is very concerned
with the socio-political developments that MM will set in motion. We are excited
about the energy and creativity that Martin will bring to his activities with
CRN. Congratulations, and welcome, Martin!
Events Coordinator
To educate, engage, and empower others to prepare for molecular manufacturing,
CRN is now offering two-day Nano-Workshops (see below). There may be a paid
position for someone to help us plan and coordinate these events, especially
if that person can identify and solicit prospective recipients of workshop
presentations. We’re also seeking additional speaking
engagements in 2005. Someone who can solicit such opportunities for
CRN Principals and manage our speaking and presentation calendar might occupy
a part-time paid position, either combined with or separate from managing
our workshops. If you’re interested, please contact Executive Director Mike
Treder.
Nano-Workshops
One of CRN’s key
activities for 2005 will be conducting on-site Nano-Workshops, designed
to educate interested groups of people about the impending impacts of molecular
manufacturing, to assess how it may affect them and their organizations,
and to guide them in deciding what they might do about it. We’ve developed
the curriculum, which covers: 1) Technical Background for Molecular Manufacturing;
2) Introduction to Implications; 3) Projections of Molecular Manufacturing
Development; and 4) Impact and Implications, with focus on the audience's
concerns. The workshops will be interactive, will include group brainstorming,
and will aim at forming a long-range action plan for the group to pursue.
Do you know of a company, a school, a nonprofit organization, or another group
that might be interested in learning about the future of nanotechnology and
how it could affect them? We’re laying out our calendar now, and the
first three groups to book a workshop will benefit from a significant discount—so
please encourage them to contact
us right away.
Symposium on Nanotechnology
In connection with their hugely popular annual
conference, the World Future Society has announced "an exploration series
designed to provide an outline of several critical new fields with the potential
for significant impact on the social, economic, and cultural fabric of modern
society." For this year, they have organized a Symposium
on Nanotechnology, which Mike Treder will assist in presenting. It’s
happening in Chicago on July 29, 2005.
New Paper Posted
The paper that Mike presented at the November 2004 International
Congress of Nanotechnology, which is titled "Bridges to Safety, and
Bridges to Progress", has been posted
on our website.
Here’s the abstract: Advanced nanotechnology offers unprecedented
opportunities for progress—defeating poverty, starvation, and disease,
opening up outer space, and expanding human capacities. But it also brings
unprecedented risks—massive job displacement causing economic and social
disruption, threats to civil liberties from ubiquitous surveillance, and the
specter of devastating wars fought with far more powerful weapons of mass
destruction. The challenge of achieving the goals and managing the risks of
nanotechnology requires more than just brilliant molecular engineering. In
addition to scientific and technical ingenuity, other disciplines and talents
will be vitally important. No single approach will solve all problems or address
all needs. The only answer is a collective answer, and that will demand an
unprecedented collaboration—a network of leaders in business, government,
academia, and NGOs. It will require participation from people of many nations,
cultures, languages, and belief systems. Never before have we faced such a
tremendous opportunity—and never before have the risks been so great.
We must begin building bridges that will lead to safety and progress for the
entire world; bridges that will develop common understanding, create lines
of communication, and create a stable structure that will enable humankind
to pass safely through the transition into the nano era.
Feature Essay: What Is Molecular Manufacturing?
Chris Phoenix, Director of Research, CRN
The term "molecular manufacturing" has been associated with all sorts of futuristic
stuff, from bloodstream robots to grey
goo to tabletop factories that can make a new factory in a few hours.
This can make it hard for people who want to understand the field to know
exactly what's
being claimed and studied. This essay explains what the term originally
meant, why the approach is thought to be powerful enough to create a field
around, why so many futuristic ideas are associated with it, and why some
of those ideas are more plausible than they may seem.
Original Definition
Eric Drexler defined the term "molecular manufacturing" in his 1992 technical
work Nanosystems.
His definition used some other terms that need to be considered first.
Mechanochemistry In this volume, the chemistry of processes in which mechanical systems operating with atomic-scale precision either guide, drive, or are driven by chemical transformations.
In other words, mechanochemistry is the direct, mechanical control of molecular structure formation and manipulation to form atomically precise products. (It can also mean the use of reactions to directly drive mechanical systems—a process that can be nearly 100% efficient, since the energy is never thermalized.) Mechanochemistry has already been demonstrated: Oyabu has used atomic force microscopes, acting purely mechanically, to remove single silicon atoms from a covalent lattice and put them back in the same spot.
Mechanosynthesis Chemical synthesis controlled by mechanical systems operating with atomic-scale precision, enabling direct positional selection of reaction sites; synthetic applications of mechanochemistry. Suitable mechanical systems include AFM mechanisms, molecular manipulators, and molecular mill systems.
In other words, mechanosynthesis is the use of mechanically guided molecular reactions to build stuff. This does not require that every reaction be directly controlled. Molecular building blocks might be produced by ordinary chemistry; products might be strengthened after manufacture by crosslinking; molecular manufactured components might be joined into products by self-assembly; and building blocks similar to those used in self-assembly might be guided into chosen locations and away from alternate possibilities. Drexler’s definition continues:
Processes that fall outside the intended scope of this definition include reactions guided by the incorporation of reactive moieties into a shared covalent framework (i.e., conventional intramolecular reactions), or by the binding of reagents to enzymes or enzyme-like catalysts.
The point of this is to exclude chemistry that happens by pure self-assembly and cannot be controlled from outside. As we will see, external control of the reactions is the key to successful molecular manufacturing. It is also the main thing that distinguishes molecular manufacturing from other kinds of nanotechnology.
The principle of mechanosynthesis—direct positional control—can be useful with or without covalent bonding. Building blocks like those used in self-assembly, held together by hydrogen bonding or other non-covalent interactions, could also be joined under mechanical control. This would give direct control of the patterns formed by assembly, rather than requiring that the building blocks themselves encode the final structure and implement the assembly process.
Molecular manufacturing The production of complex structures via nonbiological mechanosynthesis (and subsequent assembly operations).
There is some wiggle room here, because "complex structures" is not defined. Joining two molecules to make one probably doesn't count. But joining selected monomers to make a polymer chain that folds into a predetermined shape probably does.
Machine-phase chemistry The chemistry of systems in which all potentially reactive moieties follow controlled trajectories (e.g., guided by molecular machines working in vacuum).
This definition
reinforces the point that machine-phase chemistry is a narrow subset of
mechanochemistry. Mechanochemistry does not require that all molecules
be controlled; it only requires that reactions between the molecules must
be controlled. Mechanochemistry is quite compatible with "wet" chemistry,
as long as the reactants are chosen so that they will only react in the
desired locations. A ribosome appears to fit the requirement; Drexler
specified that molecular manufacturing be done by nonbiological mechanosynthesis,
because otherwise biology would be covered by the definition.
Although it has not been well explored, machine-phase chemistry has some theoretical
advantages that make it worth further study. But molecular manufacturing does
not depend on a workable machine-phase chemistry being developed. Controversies
about whether diamond can be built in vacuum do not need to be settled in
order to assess the usefulness of molecular manufacturing.
Extending Molecular Manufacturing
As explained in the first section, the core of molecular manufacturing is
the mechanical control of reactions so as to build complex structures. This
simple idea opens up a lot of possibilities at the nanoscale. Perhaps the
three most important capabilities are engineering, blueprint delivery, and
the creation of manufacturing tools. These capabilities reinforce each other,
each facilitating the others.
It is often thought that the nanoscale is intractably complex, impossible
to analyze. Nearly intractable complexity certainly can be found at the nanoscale,
for example in the prediction of protein folding. But not everything at the
nanoscale is complex. DNA folding, for example, is much simpler, and the engineering
of folded structures is now pretty straightforward. Crystals and self-assembled
monolayers also have simple aspects: they are more or less identical at a
wide range of positions. The mechanical properties of nanoscale structures
change as they get extremely small, but even single-nanometer covalent solids
(diamond, alumina, etc) can be said to have a well-defined shape.
The ability to carry out predictable synthesis reactions at chosen sites or
in chosen sequences should allow the construction of structures that are intricate
and functional, but not intractably complex. This kind of approach is a good
fit for engineering. If a structure is the wrong shape or stiffness, simply
changing the sequence of reactions used to build it will change its structure—and
at least some of its properties—in a predictable way.
It is not always easy to control things at the nanoscale. Most of our tools
are orders of magnitude larger, and more or less clumsy; it's like trying
to handle toothpicks with telephone poles. Despite this, a few techniques
and approaches have been developed that can handle individual molecules and
atoms, and move larger objects by fractions of nanometers. A separate approach
is to handle huge numbers of molecules at once, and set up the conditions
just right so that they all do the same thing, something predictable and useful.
Chemistry is an example of this; the formation of self-assembled monolayers
is another example. The trouble with all of these approaches is that they
are limited in the amount of information that can be delivered to the nanoscale.
After a technique is used to produce an intermediate product, a new technique
must be applied to perform the next step. Each of these steps is hard to develop.
They also tend to be slow to use, for two reasons: big tools move slowly,
and switching between techniques and tools can take a lot of time.
Molecular manufacturing has a big advantage over other nanoscale construction
techniques: it can usefully apply the same step over and over again. This
is because each step takes place at a selected location and with selected
building blocks. Moving to a different location, or selecting a different
building block from a predefined set, need not insert enough variation into
the process to count as a new step that must be developed and characterized
separately.
A set of molecular manufacturing operations, once worked out, could be recombined
like letters of an alphabet to make a wide variety of predictable products.
(This benefit is enhanced because mechanically guided chemistry can play useful
games with reaction barriers to speed up reactions by many orders of magnitude;
this allows a wider range of reactants to be used, and can reduce the probability
of unwanted side reactions.) The use of computer-controlled tools and computer-aided
translation from structure to operation sequence should allow blueprints to
be delivered directly to the nanoscale.
Although it is not part of the original definition of molecular manufacturing,
the ability to build a class of product structures that includes manufacturing
the tools used to build them may be very useful. If the tools can be
engineered by the same skill set that produces useful products, then research
and development may be accelerated. If new versions of tools can be constructed
and put into service within the nanoscale workspace, that may be more efficient
than building new macro-scale tools each time a new design is to be tested.
Finally, if a set of tools can be used to build a second equivalent set of
tools, then scaleup becomes possible.
The idea of a tool that can build an improved copy of itself may seem counterintuitive:
how can something build something else that's more complex than itself? But
the inputs to the process include not just the structure of the first tool,
but the information used to control it. Because of the sequential, repetitive
nature of molecular manufacturing, the amount of information that can be fed
to the process is essentially unlimited. A tool of finite complexity, controlled
from the outside, can build things far more physically complex than itself;
the complexity is limited by the quality of the design. If engineering can
be applied, then the design can be quite complex indeed; computer chips are
being designed with a billion transistors.
From the mechanical engineering side, the idea of tools building tools may
be suspect because it seems like precision will be lost at each step. However,
the use of covalent chemistry restores precision. Covalent reactions are inherently
digital: in general, either a bond is formed which holds the atoms together,
or the bond is missing and the atoms repel each other. This means that as
long as the molecules can be manipulated with enough precision to form bonds
in the desired places, the product will be exactly as it was designed, with
no loss of precision whatsoever. The precision required to form bonds reliably
is a significant engineering requirement that will require careful design
of tools, but is far from being a showstopper.
Scaleup
The main limitation of molecular manufacturing is that molecules are so small.
Controlling one reaction at a time with a single tool will produce astonishingly
small masses of product. At first sight, it may appear that there is no way
to build anything useful with this approach. However, there is a way around
this problem, and it’s the same way used by ribosomes to build an elephant:
use a lot of them in parallel. Of course, this requires that the tools must
be very small, and it must be possible to build a lot of them and then control
them all. Engineering, direct blueprint injection, and the use of molecular
manufacturing tools to build more tools can be combined to achieve this.
The key question is: How rapidly can a molecular manufacturing tool create
its own mass of product? This value, which I'll call "relative productivity," depends
on the mass of the tool; roughly speaking, its mass will be about the cube
of its size. For each factor of ten shrinkage, the mass of the tool will decrease
by 1,000. In addition, small things move faster than large things, and the
relationship is roughly linear. This means that each factor of ten shrinkage
of the tool will increase its relative productivity by 10,000 times; relative
productivity increases as the inverse fourth power of the size.
A typical scanning probe microscope might weigh two kilograms, have a size
of about 10 cm, and carry out ten automated operations per second. If each
operation deposits one carbon atom, which masses about 2x10-26 kg,
then it would take 1026 seconds or six billion billion years for
that scanning probe microscope to fabricate its own mass. But if the tool
could be shrunk by a factor of a million, to 100 nm, then its relative throughput
would increase by 1024, and it would take only 100 seconds to fabricate
its own mass. This assumes an operation speed of 10 million per second, which
is about ten times faster than the fastest known enzymes (carbonic anhydrase
and superoxide dismutase). But a relative productivity of 1,000 or even 10,000
seconds would be sufficient for a very worthwhile manufacturing technology.
(An inkjet printer takes about 10,000 seconds to print its weight in ink.)
Also, there is no requirement that a fabrication operation deposit only one
atom at a time; a variety of molecular fragments may be suitable.
To produce a gram of product will take on the order of a gram of nanoscale
tools. This means that huge numbers of the tools must be controlled in parallel:
information and power must be fed to each one. There are several possible
ways to do this, including light and pressure. If the tools can be fastened
to a framework, it may be easier to control them, especially if they can build
the framework and include nanoscale structures in it. This is the basic concept
of a nanofactory.
Nanofactories and Their Products
A nanofactory is (will be) an integrated manufacturing system containing large
numbers of nanoscale molecular manufacturing workstations (tool systems).
This appears to be the most efficient and engineerable way to make nanoscale
productive systems produce large products. With the workstations fastened
down in known positions, their nanoscale products can more easily be joined.
Also, power and control signals can be delivered through hardwired connections.
The only way to build a nanofactory is with another nanofactory. However,
the product of a nanofactory may be larger than itself; it does not appear
conceptually or practically difficult to build a small nanofactory with a
single molecular manufacturing tool, and build from there to a kilogram-scale
nanofactory. The architecture of a nanofactory must take several problems
into account, in addition to the design of the individual fabrication workstations.
The mass and organization of the mounting structure must be included in the
construction plans. A small fraction (but large number) of the nanoscale equipment
in the nanofactory will be damaged by background radiation, and the control
algorithms will have to compensate for this in making functional products.
To make heterogeneous products, the workstations and/or the nanoproduct assembly
apparatus must be individually controlled; this probably requires control
logic to be integrated into the nanofactory.
It may seem premature to be thinking about nanofactory design before the first
nanoscale molecular manufacturing system has been built. But it is important
to know what will be possible, and how difficult it will be, in order to estimate
the ultimate payoff of a technology and the time and effort required to achieve
it. If nanofactories were impossible, then molecular manufacturing would be
significantly less useful; it would be very difficult to make large products.
But preliminary studies seem to show that nanofactories are actually not very
difficult to design, at least in broad outline. I have written an 80-page
paper that covers error handling, mass and layout, transport of feedstock,
control of fabricators, and assembly and design of products for a very primitive
nanofactory design. My best estimate is that this design could produce a
duplicate nanofactory in less than a day. Nanofactory designs have been
proposed that appear to be much more flexible in how the products are formed,
but they have not yet been worked out in as much detail.
If there is a straightforward path from molecular manufacturing to nanofactories,
then useful products will
not be far behind. The ability to specify every cubic nanometer of an integrated
kilogram product, filling the product with engineered machinery, will at least
allow the construction of extremely powerful computers. If the construction
material is strong, then mechanical performance may also be extremely good;
scaling laws predict that power density increases as the inverse of machine
size, and nanostructured materials may be able to take advantage of almost
the full theoretical strength of covalent bonds rather than being limited
by propagating defects.
Many products have been imagined for this technology. A few have been designed
in sufficient detail that they might work as claimed. Robert Freitas's Nanomedicine
Vol. I contains analyses of many kinds of nanoscale machinery. However,
this only scratches the surface. In the absence of more detailed analysis
identifying quantitative limits, there has been a tendency for futurists
to assume that nano-built products will achieve performance close to the
limits of physical law. Motors three to six orders of magnitude more powerful
than today's; computers six to nine orders of magnitude more compact and
efficient; materials at least two orders of magnitude stronger—all
built by manufacturing systems many orders of magnitude cheaper—it's
not hard to see why futurists would fall in love with this field, and skeptics
would dismiss it. The solution is threefold: 1) open-minded but quantitative
investigation of the theories
and proposals that have already been made; 2) constructive attempts
to fill in missing details; and 3) critical efforts to identify unidentified
problems with the application of the theories.
Based on a decade and a half of study, I am satisfied that some kind of nanofactory
can be made to work efficiently enough to be more than competitive with today's
manufacturing systems, at least for some products. In addition, I am satisfied
that molecular manufacturing can be used to build simple, high-performance
nanoscale devices that can be combined into useful, gram-scale, high-performance
products via straightforward engineering design. This is enough to make molecular
manufacturing seem very interesting, well worth further
study; and in the absence of evidence to the contrary, worth a measure
of preliminary concern over how some of its possible products might be used.
C-R-Newsletter #26 January 3, 2005
CONTENTS
Happy
Birthday to CRN!
X
Prize Proposals
CRN
Blog Highlights
Nano-Workshops
Staff
Positions Available
Year
in Review
Feature
Essay: Advantages of Engineered Nanosystems
=========
Happy
Birthday to CRN!
In December 2002, Chris
Phoenix and Mike Treder founded the Center for Responsible Nanotechnology.
So, we've just celebrated our second birthday. It's been an eventful two
years, with a lot learned and, we think, a lot accomplished. Many thanks
to all of you who have contributed your time, your advice, your financial
support, and your interest in our work. We're looking forward to another
great year in 2005.
X Prize Proposals
The X
Prize people—who inspired SpaceShipOne—are at it again,
and this time they're interested in molecular manufacturing (among other
things). CRN is suggesting a prize proposal to encourage the development
of a primitive molecular manufacturing capability. We believe this is the
responsible thing to do. The machine we describe would make less powerful
products, which we think implies less disruption. What it would do is serve
as a proof of principle and stimulate discussion.
Chris has created a Wise-Nano
page containing his proposal. The page also contains another X-prize
proposal by Robert Freitas (author of Nanomedicine) that's intended to jump-start
diamondoid molecular manufacturing more directly. Although the proposals
have been submitted already, comments are welcomed at the Wise-Nano "discussion" page.
CRN Blog Highlights
A few of the more interesting subject headings of the last month at our blog
site, which have inspired fascinating discussions, are:
|
|
Wisdom Isn’t Easy |
|
|
Upside vs. Downside |
|
|
Invisibility |
|
|
Transformative Impacts |
The daily weblog continues
to be both a rewarding and an increasingly popular project for CRN.
Nano-Workshops
One of CRN's key
activities for 2005 will be conducting on-site Nano-Workshops, designed
to educate interested groups of people about the impending impacts of molecular
manufacturing, to assess how it may affect them and their organizations,
and to guide them in deciding what they might do about it. We've developed
the curriculum, which covers: 1) Technical Background, 2) Implications Foundation,
3) Development, and 4) Targeted Impact. The workshops will be interactive,
will include group brainstorming, and will aim at forming a long-range action
plan for the group to pursue.
Do you know of a company, a school, a nonprofit organization, or another group
that might be interested in learning about the future of nanotechnology and
how it could affect them? We're laying out our calendar now, and the first
three groups to book a workshop will benefit from a significant discount—so
please encourage them to contact
us right away.
Staff Positions Available
For CRN to become an even stronger worldwide influence in the development
of responsible nanotechnology policy, we must expand in 2005. We need assistance
from volunteer workers and possibly also from paid staff (part-time to start).
The jobs we need to fill are in three general areas: Organization, Communications,
and Appearances.
Organization – We need someone to help maintain records of C-R-Network membership,
coordinate communication with Network members, promote opportunities for student
research collaborations within educational networks, and so on. This
is a volunteer job, which might require 10 to 20 hours per month.
Communications – There are several functions that fall under
this heading, such as writing/editing this newsletter, maintaining an up-to-date
newsletter subscription list, and compiling and publishing our quarterly Responsible
Nanotechnology Report. Other jobs, which could be handled by one or more volunteers,
include editing and monitoring CRN's daily
weblog, editing the Wise-Nano.org site,
and coordinating the publication of our CRN Nano-Workbooks.
Appearances – To educate, engage, and empower others to prepare
for molecular manufacturing, CRN is now offering two-day Nano-Workshops (see
above). There may be a paid position for someone to help us plan and coordinate
these events, especially if that person can identify and solicit prospective
recipients of workshop presentations. We're also seeking additional speaking
engagements in 2005. Someone who can solicit such opportunities for
CRN Principals and manage our speaking and presentation calendar might occupy
a part-time paid position, either combined with or separate from managing
our workshops.
If you want more information about filling any of these roles, please
contact Executive Director Mike Treder. Thanks!
Year in Review
All in all, 2004 was a remarkable 12 months for CRN, and for nanotechnology
in general. Let's see, we traveled to China, Brazil,
England, Canada, and all around the USA to give speeches and presentations.
We made highly valuable contacts in Sweden, India, Spain, Turkey, Italy, and
many other places. Chris was awarded a research
grant from NASA's Institute for Advanced Concepts, and Mike was able
to start working full-time for CRN. We opened beneficial dialogue with government
officials in the United States and other countries. Perhaps most rewarding
is the contribution we made in elevating the level of discussion about responsible
development of nanotechnology, and our success in engaging skeptics and
critics in productive debate. Whew, what a year!
We're preparing a more detailed rundown of our activities in 2004 for publication
in our next Quarterly Report. You'll receive that if you are a member of the
C-R-Network, and if you're not, perhaps you should sign
up.
Feature Essay: Advantages of Engineered Nanosystems
Chris Phoenix, Director of Research, CRN
Today, biology implements by far the most advanced nanomachines on the planet.
It is tempting to think that biology must be efficient, and that we can't
hope to design nanomachines with higher performance. But we already know some
techniques that biology has never been able to try. This essay discusses several
of them and explains why biology could not use them, but manufactured nanomachines
will be able to.
Low Friction Via Superlubricity
Imagine you're pulling a toy wagon with square wheels. Each time a wheel turns
past a corner, the wagon lurches forward with a thump. This would waste substantial
amounts of energy. It's as though you're continually pulling the wagon up
tiny hills, which it then falls off of. There's no way to avoid the waste
of energy.
At the molecular scale, static friction is like that. Forces between the molecules
cause them to stretch out of position, then snap into a new configuration.
The snap, or clunk, requires energy—which is immediately dissipated
as heat.
In order for a sliding interface to have low friction, there must be an extremely
small difference in energy between all adjacent positions or configurations.
But between most surfaces, that is not the case. The molecular fragments at
the surface are springy and adhesive enough that they grab hold, get pulled,
and then snap back, wasting energy.
There are several ways in which a molecule can be pulled or pushed out of
position. If the interface is rough or dirty, the surfaces can be torn apart
as they move. This of course takes a lot of energy, producing very high friction.
Even apparently smooth surfaces can be sources of friction. If the surface
is coated with molecular bumps, the bumps may push each other sideways as
they go past, and then spring back, wasting energy. Even if the bumps are
too short and stiff to be pushed sideways very far, they can still interlock,
like stacking egg cartons or ice cube trays. (Thanks to Wikipedia for
this analogy.) If the bumps interlock strongly, then it may take a lot of
force to move them past each other—and just as they pass the halfway
point, they will snap into the next interlocking position, again wasting energy.
One way to reduce this kind of friction is to separate the surfaces. A film
of water or oil can make surfaces quite slippery. But another way to reduce
friction is to use stiff surfaces that don't line up with each other. Think
back to the egg-carton image. If you turn one of the cartons so that the bumps
don't line up, then they can't interlock; they will simply skim past each
other. In fact, friction too low to measure has been observed with graphite
sheets that were turned so as to be out of alignment. Another way to prevent
alignment is to make the bumps have different spacing, by choosing different
materials with different atoms on their surfaces.
This low-friction trick, called superlubricity, is difficult to achieve in
practice. Remember that the surfaces must be very smooth, so they can slip
past each other; and very stiff, so the bumps don't push each other sideways
and spring back; and the bumps must not line up, or they will interlock. Biological
molecules are not stiff enough to use the superlubricity trick. Superlubricity
may be counterintuitive to people who are accustomed to the high friction
of most hard dry surfaces. But experiments have shown [PDF]
that superlubricity works. A variety of materials that have been proposed
for molecular manufacturing should be stiff enough to take advantage of superlubricity.
Electric Currents
The kind of electricity that we channel in wires is made up of vast quantities
of electrons moving through the wire. Electrons can be made to move by a magnetic
field, as in a generator, or by a chemical reaction, as in a battery. Either
way, the moving electrons can be sent for long distances, and can do useful
work along the way. Electricity is extremely convenient and powerful, a foundation
of modern technology.
With only a few exceptions like electric eels, biological organisms do not
use this kind of electricity. You may know that our nerve cells use electricity.
But instead of moving electrons, biology uses ions—the "charged" atoms
that remain when one or more electrons are removed. Ions can move from place
to place, and can do work just like electrons. Bacteria use ions to power
their flagella "tails." Ions moving suddenly through a nerve cell membrane
cause a change that allows more ions, further along the cell, to be able to
move, creating a domino effect that ripples from one end of the cell to the
other.
Ions are convenient for cells to handle. An ion is much larger than an electron,
and is therefore easier to contain. But ions have to move slowly, bumping
through the water they are dissolved in. Over long distances, electrons in
a wire can deliver energy far more rapidly than ions in a liquid. But wires
require insulation.
It is perhaps not surprising that biology hasn't used electron currents. At
cellular scales, ions diffuse fast enough to do the job. And the same membranes
that keep chemicals properly in (or out of) the cell can also keep ions contained
where they can do useful work. But if we actually had "nerves of steel", we
could react far more quickly than we do.
To use electron currents, all that's needed is a good conductor and a good
insulator. Carbon nanotubes can be both conductors and insulators, depending
on how they are constructed. Many organic molecules are insulating, and some
are conductive. There is a lot of potential for molecular manufacturing to
build useful circuits, both for signaling and for power transmission.
Deterministic Machines
Cells have to reconfigure themselves constantly in response to changing conditions.
They are built out of individual molecules, loosely associated. And the only
connection between many of the molecular systems is other molecules diffusing
randomly through the cell's interior. This means that the processes of the
cell will happen unpredictably, from molecules bumping into each other after
a random length of time. Such processes are not deterministic: there's no
way to know exactly when a reaction or process will happen. This lack of tight
connection between events makes the cell's processes more adaptable to change,
but more difficult to engineer.
Engineered nanosystems can be designed, and then built and used, without needing
to be reconfigured. That makes it easier to specify mechanical or signal linkages
to connect them and make them work in step, while a constantly changing configuration
would be difficult to accommodate. Of course, no linkage is absolutely precise,
but it will be possible to ensure that, for example, an intermediate stage
in a manufacturing process always has its input ready at the time it begins
a cycle. This will make design quite a bit easier, since complex feedback
loops will not be required to keep everything running at the right relative
speed. This also makes it possible to use standard digital logic circuits.
Digital Logic
Digital logic is general-purpose and easy to engineer, which makes it great
for controlling almost any process. But it requires symbolic codes and rapid,
reliable computation. There is no way that the diffuse statistical chemical
signaling of biology could implement a high-speed microprocessor (CPU). But
rapid, lock-stepped signals make it easy. Biology, of course, doesn't need
digital logic, because it has complex control loops. But complex things are
very difficult to engineer. Using digital logic instead of complexity will
allow products to be designed much more quickly.
Rapid Transport and Motion
Everything in a cell is flooded with water. This means that everything that
moves experiences high drag. If a nanomachine can be run dry, its parts can
move more efficiently and/or at higher speeds.
Things that move by diffusion are not exempt from drag: it takes as much energy
to make objects diffuse from point A to point B in a certain time as it does
to drag it there. Although diffusion seems to happen "by itself", to work
as a transportation system it requires maintaining a higher concentration
of particles (e.g. molecules) at the source than at the destination. This
requires an input of work.
In a machine without solvent, diffusion can't work, so particles would have
to be transported mechanically. (In theory, certain small molecules could
be released into vacuum and bounce around to their destination, but this has
practical difficulties that probably would make it not useful.) Mechanical
transportation sounds inefficient, but in fact it can be more efficient than
diffusion. Because the particle is never released, energy is not required
to find and recapture it. Because nothing has to move through fluid, frictional
forces can be lower for the same speed, or speeds can be higher for the same
energy consumption. The use of machinery to move nanoparticles and molecules
may seem wasteful, but it replaces the need to maintain a pathway of solvent
molecules; it may actually require less mass and volume. The increased design
complexity of the transport machinery will be more or less balanced by the
reduced design complexity of the receiving stations for particles.
It is not only transport that can benefit from running without solvent. Any
motion will be subject to drag, which will be much higher in liquid than in
gas or vacuum. For slow motions, this is not so important. But to obtain high
power density and processing throughput, machines will have to move quickly.
Drying out the machines will allow greater efficiency than biology can attain.
Biology has never developed the ability to work without water. Engineered
machines can do so.
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