ABSTRACT
The concept of Robotic foglets is based on the concept of tiny self replicating robots. The Utility fog is just an extension of this idea. The concept of utility fog is introduced as a useful provocation for imagining nanotechnology and its implications in the future. A description of the technical specifications and uses of utility fog are provided. Utility fog is a concept that was developed by Dr. John Storrs Hall. It relies on molecular manufacturing techniques to create tiny robots. The timescale for realization of utility fog and other similar products is probably at least twenty to thirty years away. In this concept the utility fog consists of robotic cells or ‘foglets’ of about 100 microns in size .Each foglet is equipped with a high capability processing controller and electric motor. The central body is approximately spherical, about ten microns. Each body has twelve telescopic arms about five microns in diameter and fifty microns long that swivel on a universal joint. The end of the arms allows for foglets to grip together and thus forms different shape and sized objects. The fog could be manipulated by a remote control that could appear wand-like. This is a clever observation given that the utility fog could enable creation, levitation, manipulation, teleportation and shape-shifting. Suddenly the magic in Harry Potter no longer look likes fantasy. Utility fog should be capable of simulating most everyday materials, dynamically changing its form and forming a substrate for an integral virtual reality. This paper will examine the basic concept, and explore some of the applications of this material.
TABLE OF CONTENTS DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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Abstract
1
List of figures
3
Chapter No
Title
Page No.
1
Introduction
4
2
Behind the scene
7
2.1
The Stuffs that Dreams are made of
7
2.2
Modes of operation
9
How to Build a Fog
11
3.1
Design Issues
11
3.2
Utility Fog: The components proposed
13
3.2.1
A Foglet
17
3.2.2
The grip
18
Foglets in detail
19
Foglets – internal schematic
21
4
Communication and Control
23
5
Combination with other technologies
25
6
General properties and uses
27
7
Limitations of utility fog capability
28
Other desirable limitations
29
8
Advantages of a utility fog environment
31
9
Applications
33
Space Exploration
33
10
Conclusion
35
11
References
36
3
3.3 3.3.1
7.1
9.1
LIST OF FIGURES
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Fig. No.
NAME
PAGE No.
2.1
The expansion of a foglet
8
2.2.1
Arrangement of Utility Fog
10
3.2.1
Foglet having 12 arms
13
3.3.1
Connecting Structure of a Foglet
16
3.2.2
The Grip of a Foglet
17
3.3.1
Internal Diagram of a Foglet
20
3.3.2
Three layers of foglets
21
Chapter 1
INTRODUCTION
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Imagine a microscopic robot. It has a body about the size of a human cell and 12 arms sticking out in all directions. A bucketful of such robots might form a "robot crystal" by linking their arms up into a lattice structure. Now take a room, with people, furniture, and other objects in it it’s still mostly empty air. Fill the air completely full of robots. With the right programming, the robots can exert any force in any direction on the surface of any object. They can support the object, so that it apparently floats in the air. They can support a person, applying the same pressures to the seat of the pants that a chair would. They can exert the same resisting forces that elbows and fingertips would receive from the arms and back of the chair. A program running in the Utility Fog can thus simulate the physical existence of an object. Although this class of nanotechnology has been envisioned by the technocracy since early times, and has been available to us for over twenty years, the name is more recent. A mundane scientist, J. Storrs Hall provided an important baseline examination of the issues involved in the application and design of Utility fog. He envisioned it as an active polymorphic material designed as a conglomeration of 100micronrobotic cells or foglets, built using molecular nanotechnology. An appropriate mass of Utility Fog could be programmed to simulate, to the same precision as measured by human senses, most of the physical properties, such as hardness, temperature, light, of any macroscopic object, including expected objects such as tables and fans, but also materials such as air and water. The major exceptions would be taste, smell, and transparency. To users, it would seem like the Star Trek Helideck except that it would use atoms instead of holographic illusions. It is an indication of the degree to which our science and technology have permeated society that a non member could so accurately describe and visualise the way in which "Utility Fog" operates. Nanotechnology is based on the concept of tiny, self-replicating robots. The Utility Fog is a very simple extension of the idea: Suppose, instead of building the object you want atom by atom, the tiny robots linked their arms together to form a solid mass in the shape of the object you wanted? Then, when you got tired of that simple table, the robots could simply shift around a little and you'd have an elegant table instead. DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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The colour and reflectivity of an object are results of its properties as an antenna in the micron wavelength region. Each robot could have an "antenna arm" that it could manipulate to vary those properties, and thus the surface of a Utility Fog object could look just about however you wanted it to. A "thin film" of robots could act as a video screen, varying their optical properties in real time. Rather than paint the walls, coat them with Utility Fog and they can be a different colour every day, or act as a floor to-ceiling TV. Indeed, make the entire wall of the Fog and you can change the floor plan of your house to suit the occasion. Make the floor of it and never gets dirty, looks like hardwood but feels like foam rubber, and extrudes furniture in any form you desire. Indeed, your whole domestic environment can be constructed from Utility Fog; it can form any object you want (except food) and whenever you don't want an object any more, the robots that formed it spread out and form part of the floor again. You may as well make your car of Utility Fog, too; then you can have a "new" one every day. But better than that, the *interior* of the car is filled with robots as well as its shell. You'll need to wear holographic "eye phones" to see, but the Fog will hold them up in front of your eyes and they'll feel and look as if they weren't there. Although heavier than air, the Fog is programmed to simulate its physical properties, so you can't feel it: when you move your arm, it flows out of the way. Except when there's a crash! Then it forms an instant form-fitting "seatbelt" protecting every inch of your body. You can take a 100-mph impact without messing your hair. Remember that each of these robots contains a fair-sized computer. They already have to be able to talk to each other and coordinate actions in a quite sophisticated way (even the original Nano-assemblers have to, build Division any macroscopic object). You can simply cover the road with a thick layer of robots. Then your car "calls ahead" and makes a reservation for every position in time and space it will occupy during the trip.
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Chapter 2
BEHIND THE SCENE 2.1 THE STUFF THAT DREAMS ARE MADE OF In the late twenty-first century, the “real” world will take on many of the characteristics of the virtual world through the means of nanotechnology “swarms.” DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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Consider, for example, Rutgers University computer scientist J. Storrs Hall’s concept of “Utility Fog”. Hall’s conception starts with a little robot called a Foglet, which consists of a human cell-sized device with twelve arms pointing in all directions. At the end of the arms are grippers so that the Foglets can grasp one another to form larger structures. These nanorobots are intelligent and can merge their computational capacities with each other to create a distributed intelligence. A space filled with Foglets is called Utility Fog and has some interesting properties. First of all, the Utility Fog goes to a lot of trouble to simulate it's not being there. Hall describes detailed scenarios that lets a real human walk through a room filled with trillions of Foglets and not notice a thing. When desired (and it’s not entirely clear whose doing the desiring), the Foglets can quickly simulate any environment by creating all sorts of structures. As Hall puts it, “Fog city can look like a park, or a forest, or ancient Rome one day and Emerald City the next. The Foglets can create arbitrary wave fronts of light and sound in any direction to create any imaginary visual and auditory environment. They can exert any pattern of pressure to create any tactile environment. In this way, Utility Fog has all the flexibility of a virtual environment, except it exists in the real physical world. The distributed intelligence of the Utility Fog can simulate the minds of scanned (Hall calls them “uploaded”) people who are recreated in the Utility Fog “Fog people.” In Hall’s scenario, “a biological human can walk through Fog walls, and a Fog (uploaded) human can walkthrough dumb-matter walls. Of course Fog people can walk through Fog walls, too.” The physical technology of Utility Fog is actually rather conservative. The Foglets are much bigger machines than most nanotechnology conceptions. The software is more challenging, but ultimately feasible. Hall needs a bit of work on his marketing angle: Utility Fog is a rather dull name for such versatile stuff. There are a variety of proposals for nanotechnology swarms, in which the real environment is constructed from interacting multitudes of nanomachines. In all of the swarm conceptions, physical reality becomes a lot like virtual reality you can be sleeping in your bed one moment, and have the room transform into your kitchen as you awake. Actually, change that to a dining room as there’s no need for a kitchen. Related nanotechnology will instantly create whatever meal desire. When you finish eating, DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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the room can transform into a study, or a game room, or a swimming pool, or a redwood forest, or the Taj Mahal
Fig 2.1 the expansion of a foglet
2.2 MODES OF OPERATION The Nano-constructs operate in two modes - "native", and "fog". In "native" mode, individual foglets move into different positions and perform certain mechanical operations depending on what object it is forming. For example, if it forms part of actable, then it would be motionless and locked. If the object was a fan, then most of the structure would remain locked, and only the foglets between the two parts would need to move. With a suit made of Fog, you might wrestle alligators, cheating a little by having the suit amplify your movements as it protects you from the alligator's teeth. In "fog" mode, the foglets do not move, but act more like pixels on a television screen -they "pixelate". The foglets vary other properties according to which part of the object they are representing, generally transmitting information and sound. A Fog-filled room would contain 90% air, and surround its occupant with a display screen with 100 micron resolution. Meanwhile, each litre of foglets behind the DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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display would contain about billion times the processing power of a 286 PC, making possible some pretty impressive virtual reality simulations. The Utility Fog which is simulating air needs to be impalpable. One would like to be able to walk through a Fog-filled room without the feeling of having been cast into a block of solid Lucite. It is also desire-able to be able to breathe while using the Fog in this way! To this end, the robots representing empty space constantly run a fluid-flow simulation of what the air would be doing if the robots weren’t there. Then each robot does what it displaces would do in its absence. How can one breathe when the air is a solid mass of machines? Actually, it isn’t really solid: the Foglets only occupy about 10% of the actual volume of the air (they need lots of "elbow room" to move around easily). There’s plenty of air left to breathe. As far as physically breathing it, we set up a pressure-sensitive boundary which translates air motions on one side to Fog motions on the other. It might even be possible to have the Fog continue the air simulation all the way into the lungs. To understand why we want to fill the air with microscopic robots only to go to so much trouble to make it seem as if they weren’t there, consider the advantages of a TV or computer screen over an ordinary picture. Objects on the screen can appear and disappear at will; they are not constrained by the laws of physics. The whole scene can shift instantly from one apparent locale to another. Completely imaginary constructions, not possible to build in physical reality, could be commonplace. Virtually anything imaginable could be given tangible reality in a Utility Fog environment. Why not, instead, build a virtual reality machine that produces a purely sensory version of the same apparent world? The Fog acts as a continuous bridge between actual physical reality and virtual reality. The Fog is universal effectors as well as a universal sensor. Any(real) object in the Fog environment can be manipulated with an extremely wide array of patterns of pressure, force, and supported, measured, analysed, weighed, cut, reassembled, or reduced to bacteriasized pieces and sorted for recycling. Utility Fog can act as a transparent interface between
"cyberspace"
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reality.
Fig.2.2.1 Arrangement of Utility Fog.
Chapter 3
HOW TO BUILD A FOG 3.1 DESIGN ISSUES The only major breakthrough necessary to enable us to build the Fog world is nanotechnology itself. Assemblers, the sine qua non of nanotechnology, will require two major feats of molecular engineering: building molecular-sized, individually controllable, physical actuators, arms, motors, gears, sprockets, pulleys, and the like; and then building molecular sized computers to control them.
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Foglets need not be controllable to the same precision as true assemblers: They do not need to control chemical reactions at the atomic level. In fact, the only constraint on sizes is the ability to form a smooth enough surface to fool human senses. The lower limit, based on designs from Nanosystems, is about a 1 or 2 micron body and 5 to 10 micron arms. The upper limit for completely undetectable granularity is probably about 50 to 100microns, the range of diameter of human hair. If "super high fidelity" isn't critical, 1 mm Foglets would likely be able to do all the physical tasks of interest. The user, embedded in the Fog, is not really looking at it but at a synthetic image, probably generated by a pair of active holographic contact "lenses". The original designed the Foglets to be very small, so that they were less than the wavelength of light, in hopes that Fog could be transparent. After running the idea past several people, including Drexler, they managed to convince that even Foglets of subliminal size, even though quite invisible individually, would cause enough scattering that a cloud of them would look like, surprise, a cloud. For applications not involving the embedding of humans, "Foglets" could be of any size consonant with the objects they had to manipulate. Imagine building a skyscraper behaving a solid mass of robots each a foot or so in size, form an active scaffold in which beams and blocks and plates were moved around, hand over hand. Such "Foglets" could be built today; but they would be way too expensive for this kind of application. Fog needs the self-reproducing productivity of nanotechnology to be economical. After all, filling an average house with even coarse 1 mm Foglets requires over a trillion of them, and for the hi-fi Foglets it's a quadrillion (1015) of them. For you to be able to afford them they'd better cost less than $0.00000000001 apiece. (If you were very rich, you might be able to afford $0.000000001 Foglets.) What Foglets don't need is to be individually self-reproducing. Foglets, small though they may be on the macroscopic scale, are just a completely different kind of machine than self reproducing assemblers. Assembler will be most efficient when they work in vat of special precursor chemicals. This will also constitute a built-in safety factor against runaway replication: after all, you don't worry about baking yeast taking over the whole world when you make homemade bread; when it runs out of dough, it stops. Foglets operate out in the real world, with motion tolerances bigger than the assembler's entire working envelope.
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We'd expect Foglets to be built like virtually any other end product of a nanobased technology. There will in all likelihood not only be specialized Fog-making machines... The more specialized a production process is, the more efficient. The general-purpose assembler is a necessary bootstrap, but as nanotechnology matures it will engender longer and more complicated self-referential loops. The typical specialized nano-factory will be a breadbox to refrigerator-sized object, with literally trillions of parallel assembly lines converging in a tree-like structure to produce everlarger subcomponents of the end product. For something as small as a Foglets the factory could be quite a bit smaller, of course.
3.2 UTILITY FOG: THE COMPONENTS PROPOSED The components which are required to make utility fog are of a much concern for its development.
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Fig.3.2.1 Foglet having 12 arms. Most currently proposed nanotechnological designs are based on carbon. Carbon is a marvellous atom for structural purposes, forming a crystal (diamond) as shown in fig3.2.1 which is very stiff and strong. However, a Fog built of diamond would have a problem which nanomechanical designs of a more conventional form do not pose: the Fog has so much surface area exposed to the air that if it were largely diamond, especially on the surface, it would amount to a "fuel-air explosive". Therefore the Foglet is designed so that its structural elements, forming the major component of its mass, are made of aluminium oxide, a refractory compound using common elements. The structural elements form an exoskeleton, which besides being good mechanical design allows us to have an evacuated interior in which more sensitive nanomechanical components can operate. Of course, any macroscopic ignition source would vaporize the entire Foglet; but as long as more energy is used vaporizing the exoskeleton than is gained burning the carbon-based components inside, the reaction cannot spread. Each Foglet has twelve arms, arranged as the faces of a dodecahedron. The arms telescope rather than having joints. The arms swivel on a universal joint at the base, and the gripper at the end cart rotate about the arm’s axis.
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Each arm thus has four degrees of freedom, plus opening and closing the gripper. The only load-carrying motor on each axis is the extension/retraction motor. The swivel and rotate axes are weakly driven, able to position the arm in free air but not drive any kind of load; however, there are load holding brakes on these axes. The gripper is a hexagonal structure with three fingers, mounted on alternating faces of the hexagon. Two Foglets "grasp hands" in an interleaved six-finger grip. Since the fingers are designed to match the end of the other arm, this provides a relatively rigid connection; forces are only transmitted axially through the grip. When at rest, the Foglets form a regular lattice structure. If the bodies of the Foglets are thought of as atoms, it is a "face-cantered cubic" crystal formation, where each atom touches 12 other atoms. . The spaces bounded by the arms form alternate tetrahedrons And octahedrons, both of which are rigid shapes. The Fog may be thought of as consisting of layers of Foglets. Tire layers, and the shear planes they define, lie at 4 major angles (corresponding to tire faces of the tetrahedrons and octahedrons) and 3 minor ones (corresponding to tire face-cantered cube faces). In each of the 4 major orientations, each Foglet uses six arms to hold its neighbours in the layer; layers are thus a 2-dimensionally rigid fabric of equilateral triangles. In face entered mode, the layers work out to the square grids, and are thins not rigid, a slight disadvantage. Most Fog motion is organized in layers; layers slide by passing each other down hand-over-hand in bucket brigade fashion. At any instant, roughly half the arms will lie lurked between layers when they are in motion. The Fog moves an object by setting up a seed-shaped zone around it. The Foglets in the zone move with the object, forming a fairing which makes the motions around it smoother. If the object is moving fast, the Fog around its path will compress to let it go by. The air does not have time to move in the Fog matrix and so the motion is fairly efficient. For slower motions, efficiency is not so important, but if we wish top regent slow-moving high-pressure areas from interfering with other airflow operations, we can enclose the object’s zone in a self-contained convection cell which moves Foglets from in front to behind it.
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Each moving layer of robots is similarly passing the next layer along, so each layer adds another increment of the velocity difference of adjacent layers. Motors for arm extension can run at a gigahertz, and be geared down by a factor of 100 to the main screw in the arm. This will have a pitch of about a micron, giving a linear extension/retraction rate of about 10 meters per second. We can estimate the interlayer shear rate at this velocity; the foglets are essentially pulling themselves along. Thus for a 100-micron interlayer distance Fog can sustain a 100 meter-per-second shear per millimetre of thickness. The atomically-precise crystals of the Foglets’ structural members will have a tensile strength of at least 100,000 psi (i.e. high for steel but low for the materials, including some fairly refractory ceramics, used in modern "high-tech" composites). At arm's length of 100 microns, the Fog will occupy 10% of the volume of the air but has structural efficiency of only about 1% in any given direction. Thus Utility Fog as a bulk material will have a density (specific gravity) of 0.2; for comparison, balsa wood is about 0.15 and cork is about 0.25. Fog will have a tensile strength of only 1000 psi; this is about the same as low-density polyethylene (solid, not foam). The material properties arising from the lattice structure are more or less isotropic; the one exception is that when Fog is flowing, tensile strength perpendicular tithe shear plane is cut roughly in half. Without altering the lattice connectivity, Fog can contract by up to about 40% in any linear dimension, reducing its overall volume (and increasing its density) by a factor office. (This is of course done by retracting all arms but not letting go.) In this state the fog has the density of water. An even denser state can be attained by forming two interpenetrating lattices and retracting; at this point its density and strength would both be similar to ivory or Corian structural plastic, at specific gravity of 2 and about 6000 psi. Such high density Fog would have time useful property of being waterproof (which ordinary Fog is not), but it cannot flow and takes much longer to change configuration. Selective application of this technique allows Fog to simulate shapes and flow fields to precision considerably greater than 100 microns. An appropriate mass of Utility Fog can be programmed to simulate most of the physical properties of any macroscopic object (including air and water); to DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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roughly the same precision those properties are measured by human senses. The major exceptions are taste, smell, and transparency. The latter can be overcome with holographic "eye phones" if a person is to be completely embedded in Fog.
3.2.1 A FOGLET
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A foglet is the basic component of the Utility fog as several number of them forms a fog.Fig.3.3.1 Connecting Structure Of a Foglets depicted by fig 3.3.1 one can see the dodecahedral structure of the utility fog. The arms of the foglets are having grippers which are used for interconnection between two foglets. The connection socket here is used for tight combination of two arms of different foglets.
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3.2.2 THE GRIP Grip is the most important part of the foglet as the whole arrangement depends upon the interconnection of the grips.
Fig.3.2.2 the Grip of a Foglet
The Grip consists of basic four divisions. The first one is coupler which is used for the communication and power controlling purpose. It can be considered as the head of this division. Then we have Optical Waveguide for communication from the user so that it could get the commands for its performance. The power and electrical transmission lines are used for the power supply in this foglet and finally we have couplers which are used for locking of the two foglets together.
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3.3 FOGLET IN DETAIL:
Foglets run on electricity, but they store hydrogen as an energy buffer. We pick hydrogen in part because it’s almost certain to be a fuel of choice in the nanotech world, and thus we can be sure that the process of converting hydrogen and oxygen to water and energy, as well as the process of converting energy and water to hydrogen and oxygen, will be well understood. That means we’ll be able to do them efficiently, which is of prime importance. Suppose that the Fog is flowing, layers sliding against each other, and some force is being transmitted through the flow. This would happen any time the Fog moved some non-Fog object, for example. Just as human muscles oppose each other when holding something tightly, opposing forces along different Foglet arms act to hold the Fog's shape and supply the required motion. When two layers of Fog move past each other, the arms between may need to move as many as 100 thousand sand times per second. Now if each of those motions was dissipative, and the fog was under full load, it would need to consume 700 kilowatts per cubic centimetre. This is roughly the power dissipation in a .45 calibre cartridge in the millisecond after the trigger is pulled; i.e. it just won’t do. But nowhere near this amount of energy is being used; the pushing arms are supplying this much but the arms being pushed are receiving almost the same amount, minus the work being done on the object being moved. So if the motors can act as generators when they're being pushed, each Foglet’s energy budget is nearly balanced. Because these are arms instead of wheels, the intake and outflow do not match at any given instant, even though they average out the same over time (measured in tens of microseconds). Some buffering is needed. Hence hydrogen is used. I should hasten to add that almost never would one expect the Fog to move actively at1000 psi; the pressure in the column of Fog beneath, say, a "levitated" human body isles than one thousandth of that. The 1000 psi capability is to allow the Fog can simulate hard objects, where forces can be concentrated into very small areas. Even so, current exploratory engineering designs for electric motors have power conversion densities up to a billion watts per cubic centimetre, and dissipative inefficiencies in the 10 parts per million ranges. This means that if time Empire State DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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Building was being floated around on a column of Fog, time Fog would dissipate less than a watt per cubic centimetre. Moving Fog will dissipate energy by air turbulence and viscous drag. In the large, air will been trained in the layers of moving Fog and forced into laminar flow. Energy consumed in this regime may be properly thought of as necessary for the desired motion no matter how it was done. As for the waving of the arms between layers, the Reynolds Number decreases linearly with the size of the arm. Since the absolute velocity of the arms is low, i.e. 1 m/s, the Reynolds number should be well below the "lower critical" value and the arms should be operating in a perfectly viscous regime with no turbulence. The remaining effect, viscous drag (on the waving arms) comes to a few watts per square meter of shear plane per layer. There will certainly be some waste heat generated by Fog at work that will need to be dissipated. This and other applications for heat pumps, such as heating or cooling people (no need to heat the whole house, especially since some People prefer different temperatures), can be done simply by running a flow of Fog through a pipe-like volume which changes in area, compressing and expanding tire entrained air at the appropriate places.
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The figure 3.3.1 shows the internal diagram of a foglet which is the basic component of utility fog.
Fig.3.3.1 Internal Diagram of a Foglet (more or less to scale) All the working movements depends on the programming of the foglets for their arrangements.
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The Foglets arrange themselves in three layers where they slide over one another to form a new structure is as shown in Fig. 3.3.2, has three layers of foglets. If the programming says, maintain a constant total among the extension of all arms, but otherwise do whatever the forces would indicate; and when a particular arm gets to the end of its envelope, let go, and look for another arm coming into reach to grab; you have liquid. If you allow the sum of the arm extensions to vary with the sum of the force son the arms, you have something that approximates a gas within a certain pressure range. Note that because the foglets can use their own power to move or resist moving, the apparent density and viscosity of the fluid can anything from dense toner vacuum.
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Chapter 4
COMMUNICATIONS AND CONTROL In the macroscopic world, microcomputer-based controllers (e.g. the widely used Intel8051 series microcontrollers) typically run on a clock speed of about 10 MHz They emit control signals, at most, on the order of 10 kHz (usually less), and control motions in robots that are at most 10 Hz, i.e. a complete motion taking one tenth of a second. This million-clocks-per-action is not strictly necessary, of course; but it gives us some concept of the action rate we might expect for a given computer clock rate in a digitally controlled nanorobot. Drexler’s carefully detailed analysis shows that it is possible to build mechanical nanocomputers with gigahertz clock rates. Thus we can immediately expect to build nanocontroller which can direct a 10 kilohertz robot. However, we can do better. Since tire early microcontrollers were developed, computer architecture has advanced. The 8051’s do 1 instruction per 6, 12, or 18 clock cycles; modern RISC architectures execute 1 instruction per cycle. So far, nobody has bothered to build a RISC microcontroller, since they already have more computing power than they need. Furthermore, RISC designs are efficient in hardware as well as time; one early RISC was implemented on a 10,000-gate gate array. This design could be translated into rod logician less than one tenth of one percentage of a cubic micron. Each Foglet is going to have 12 arms with three axis control each. In current technology it isn’t uncommon to have a processor per axis; we could fit 36 processors into the Foglet but it isn’t necessary. The trade-offs in macroscopic robotics today are such that processors are cheap; in the Foglet timings are different. The control of the arms is actually much simpler than control of a macroscopic robot. They can be managed by much simpler controllers that take commands hike "Move to point X at speed y." Using arise design allows a single processor to control a 100 kHz arm; using auxiliary controllers will let it do all 12 easily. But there is still a problem: Each computer, even with the power-reducing reversible logic designs, is going to dissipate a few nanowatts. At a trillion foglets per DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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cubic meter, this is a few kilowatts per cubic meter. Cooling for such dissipation must needs hedonic-where between substantial and heroic. As long as the computers can go into standby mode when the Fog is standing still, however, this is quite workable. Concentrations of heavy work, mechanical or computing, would still require cooling circulation to sumac degree, but, as we have seen, the Fog is perfectly capable of doing that. What about all the other computing overhead for the Fog? Besides the individual control of its robotic self, each Foglet will have to run a portion of time overall distributed control and communications algorithms. We can do another clockspeed to capability analogy from current computers regarding communications. Megahertz-speed computers find themselves well employed managing a handful of megabit data lines, again we are forced to abandon the engineering trade-offs of the macroscopic world: routing of message through any given node need theoretically consume only a handful of thermodynamically irreversible bit operations; typical communications controllers take millions. Special-purpose message routers designed with these facts in mind must be a part of the Foglet. If the Fog were configured as a store-and-forward network, packets with an average length of 100 bytes and a 1000-instruction overhead, information would move through the Fog at 50 meters/second, i.e. 110 mph. It represents a highly inefficient use of computation even with special-purpose hardware. It will be necessary to design a more efficient communication protocol. Setting up "virtual circuits" in the Fog amid using optical repeaters (or simply mechanically switching the optical waveguides) should help considerably.
Chapter 5
COMBINATION WITH OTHER TECHNOLOGIES DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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The counterintuitive inefficiency in communications is an example, possibly the most extreme one, of a case where macroscopic mechanisms outperform the Fog at some specific task. This will be even truer when we consider nano-engineered macroscopic mechanisms. We could imagine a robot, human-sized, that was formed of collection of nano-engineered parts held together by a mass of Utility Fog. The parts might include "bones", perhaps diamond-fibber composites, having great structural strength; motors, power sources, and so forth. The parts would form a sort of erector set that the surrounding Fog would assemble to perform the task at hand. The Fog could do directly all subtasks not requiring the excessive strength, power, and so forth that the special-purpose parts would supply. The Fog house, or city, would resemble the Fog robot in that regard. The roof of a house might well be specially engineered for qualities of water proofers, solar energy collection, and resistance to general abuse, far exceeding that which ordinary general-purpose Fog would leave. (On the other hand, the Fog could, if desired, have excellent insulating properties.) Of course the roof need not be one piece-it might be inch-square tiles held in place by the supporting Fog, and thus be quite amenable to rearrangement at the owner's whim, incremental repair and replacement, and all the other advantages we expect from a Fog house. Another major component that would be special-purpose would be power and communications. Working on more-efficient protocols such as suggested above, the Fog would form an acceptable communications link from a person to some terminal in the same building; but it would be extremely inefficient for long-haul, high bandwidth connections such as that needed for telecommunication. Power is also almost certainly the domain of special-purpose nano-engineered mechanisms. Power transmission in the Fog is likely to be limited, although for differences from data transmission. Nanotechnology will give us an amazing array of power generation and distribution possibilities, and the Fog can use most of them. The critical heterogeneous component of Fog is the Fog-producing machine. Foglets are not self-reproducing; there is no need for them to be, and it would DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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complicate their design enormously to give them fine atom-manipulating capability. One imagines a Fog machine the size of a breadbox producing Fog for a house, or building-sized machines filling cities with Fog. The Fog itself, of course, conveys raw materials back to the machine.
Chapter 6
GENERAL PROPERTIES AND USES
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As well as forming an extension of the senses and muscles of individual people, the Fog can act as a generalized infrastructure for society at large. Fog City need have no permanent buildings of concrete, any roads of asphalt, any cars, trucks, or busses. It can look like a park, or a forest, or if the population is sufficiently whimsical, ancient Rome one day and Emerald City the next. It will be more efficient to build dedicated machines for long distance energy and information propagation, and physical transport. For local use, and interface to the worldwide networks, the Fog is ideal for all of these functions. It can act as shelter, clothing, telephone, computer, and automobile. It will be almost any common household object, appearing from nowhere when needed (and disappearing afterwards). It gains ascertain efficiency from this extreme of polymorphism; consider the number of hardcopy photographs necessary to store all the images one sees on a television or computer screen. With Utility Fog we can have one "display" and keep our entire physical possession on disk. Another item of infrastructure that will become increasingly important in the future is information processing. Nanotechnology will allow us to build some really monster computers. Although each Foglet will possess a comparatively small processor—which is to say the power of a current-day supercomputer—there are about 16 million Foglets a cubic inch. When those Foglets are not doing anything else, i.e. when they are simulating the interior of a solid object or air that nothing is passing through at the moment, they can be used as a computing resource (with the caveats below).
Chapter 7
LIMITATIONS OF UTILITY FOG CAPABILITY When discussing something as far outside of’ everyday experience as the Utility Fog, it is a good idea to delineate both sides of the boundary? The Fog is capable of so many literally amazing things, we will point out a few of the things it DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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isn’t capable of: Anything requiring hard metal (cold steel).For example, Fog couldn’t simulate a drill bit Cutting through hardwood. It would be able to cut the hole, but the process would be better described as intelligent sandpaper. Anything requiring both high strength and low Volume: A parachute couldn't be made of Fog (unless, of course, all the air were filled With Fog, in which case one could simply fly). Anything requiring high heat: A Fog fire blazing merrily away on Fog logs in a fireplace would feel warm on the skin a few feet away; it would feel the same to a hand inserted into the "flame". Anything requiring molecular manipulation or chemical transformation: Foglets are simply on the wrong scale to play with atoms. In particular, they cannot reproduce them. On the other hand, they can do things like prepare food the same way a hit-man cook does—by mixing, stirring, and using special-purpose devices that were designed for theta to use. Fog cannot simulate food or anything else that is destined to be broken down chemically. Eating it would be like eating the same amount of sand or sawdust. Fog can simulate air to the touch hut not to the eyes. The best Indications are that it would look like heavy fog. Thus the Fog would need to support apiary of holographic goggles in front of the eyes of an embedded user. Such goggles are clearly within the capabilities of the same level of nanotechnology as is needed for the Fog.
7.1 OTHER DESIRABLE LIMITATIONS The machine works "not wisely but too well," manifesting all the deeply buried Subconscious desires of the Krell (A play writer) to destroy each other. Utility Fog will provide humans with powers that. Approximate those of the fictional Krell machine. Luckily, we have centuries of literary tradition to guide us around the Pitfalls of hubris made reality. We must study this tradition, or we may be doomed to repeat it a truth that is by no means limited to the Utility Fog or indeed to Nanotechnology in general. DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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The first thing we can do is to require fully conscious, unequivocal commands for the Fog to take any action. Beyond that, we can try to suggest some of the protocols that maybe useful in managing the Fog in a situation where humans are interacting in close Physical proximity. Even if we have solved the problem of translating one’s individual Wishes, however expressed, into the quadrillions of sets of instructions to individual Foglets to accomplish what one desired, the problem of who gets to control which Foglets is probably a much more contentious one. We can physicalize the psychological concept of "personal space". The Foglets within Some distance of each person would be under that person’s exclusive control; personal Spaces could not merge except by mutual consent. This single protocol could prevent most crimes of violence in our hypothetical Fog City. A corollary point is that physically perpetrated theft would be impossible in a Fog world. It would still be possible by informational means, i.e. fraud, hacking, etc. but the Fog could be programmed to put ownership on the level of a physical law. Not that it really makes any sense to think of stealing a fog-mode object, anyway. Ownership and control Of the Fog need not be any more complex than the bundles of rights currently associated with everything from land to corporate stock. Indeed, much of the programming of the Fog will need to have the character of physical Laws. In order for the enormous potential complexity to be comprehensible and thus Usable to human beings, it needs to be organized by simple but powerful principles, which must be consonant with the huge amount of hard-wired information processing? Our sensory systems perform like this. For example, it would be easy to move furniture (or Buildings) by manipulating an appropriately sized scale model, and easy to observe the Effects by watching the model. However, the Fog could just as easily have flooded the Room with 100 kHz sound and frequency-scaled the echoes down into the human auditory range. A bat would have no trouble with this kind of "scale model", but to Humans it’s just noise. It will be necessary, in general, to arrange the overall control of the Fog to be extremely distributed, as local as possible, robust in the presence of failure. When we realize that single cubic inch of Fog represents a computer network of 16 million processors, the Concept of hierarchical control with human oversight can be seen to DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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be hopelessly inadequate. Algorithmic distributed control algorithms offer one possible solution.
Chapter 8
ADVANTAGES OF A UTILITY FOG ENVIRONMENT Another major advantage for space-filling Fog is safety. In a car (or its nanotech Descendant) Fog forms a dynamic form-fitting cushion that protects better than any seatbelt of nylon fibbers. An appropriately built house filled with Fog could even protect its inhabitants from the (physical) effects of a nuclear weapon within 95% or so of its lethal blast area.
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There are many more mundane ways the Fog can protect its occupants, not the least being physically to remove bacteria, mites, pollen, and so forth, from the air. A Fog filled Home would no longer be the place that most accidents happen. First, by performing most household tasks using Fog as an instrumentality, the cuts and falls that accompany the use of knives, power tools, ladders, and so forth, can be eliminated. Secondly, the other major class of household accidents, young children who injure them out of ignorance can be avoided by a number of means. A child who climbed over a stair rail would float harmlessly to the floor. A child could not pull a book case over on itself, falling over would not be among the bookcase’s repertoire. Power tools, Kitchen implements, and cleaning chemicals would not normally exist; they or their analogues would be called into existence when needed and vanish instead of having to be cleaned and put away. Outside the home, the possibilities are, if anything, greater. One can easily imagine "Industrial Fog" which forms a factory. It would consist of larger robots. Unlike domestic Fog, which would have the density and strength of balsa wood, industrial Fog could have bulk properties resembling hardwood or aluminium. A nanotechnology- age factory would probably consist of a mass of Fog with specialpurpose reactors embedded in it, where high-energy chemical transformations could take place. All the physical manipulation, transport, assembly, and so forth would be done by the Fog.
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Chapter 9
APPLICATIONS 9.1 SPACE EXPLORATION The major systems of spaceships will need to he made with special- purpose Nanotechnological mechanisms, and indeed with such mechanisms pushed much closer to their true capacities than anything we have talked about heretofore. In the spaceship's Cabin, however, will be art acceleration couch. When not accelerating, which is most of? The time, we’d prefer something useful, like empty space, there. The Utility Fog makes a better acceleration couch, anyway.
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Fill the cabin with Utility Fog and never worry about floating out of reach of a handhold. Instruments, consoles, and cabinets for equipment and sup plies are not needed. Non simulable items can be embedded in the fog in what are apparently bulkheads. The Fog can add great structural strength to the ship itself; the rest of the structure needs not much More than a balloon. The same is true for spacesuits. Fog inside the suit manages the air pressure and makes motion easy; Fog outside gives extremely fine manipulating ability for various tasks. Of course, like the ship, the suit contains many special purpose non-Fog mechanisms. Surround the space station with Fog. It needs radiation shielding anyway (if the occupants are long-term); use big Industrial Foglets with lots of redundancy in the mechanism; even so they may get recycled fairly often. All the stock problems from SF movies go away: humans never need go outside merely to fix something; when EVA is desired for transfer or recreation, Outside Fog provides complete safety and motion control. It also makes a good tugboat for docking spaceships. Homesteaders on the Moon could bring along a batch of heavy duty Fog as well as the Special-purpose nanotechnology power generation and waste recycling equipment. There will be a million and one things, of the ordinary yet arduous physical task kind, that must be done to set up and maintain a self-sufficient household.
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Chapter 10
CONCLUSION Utility fog is a term suggested by Dr. John Storrs Hall to describe a nanotechnological Collection of tiny robots together performing a certain function .Hall thought of it as nanotechnological replacement for car seatbelts and many other useful types of equipment. The robots would be microscopic, with extending arms reaching in several different directions, and could perform lattice reconfiguration. Grabbers at the ends of the arms would allow the robots (or foglets) to mechanically link to one another and share both Information and energy, enabling them to act as a continuous substance with mechanical and optical properties that could be varied over a wide range. Each foglet would have substantial computing power, and would be able to communicate with its neighbours.
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While the foglets would be micro-scale, construction of the foglets would require full molecular technology. Each robot would be in the shape of a dodecahedron with 12 arms extending outwards. Each arm would have four degrees of freedom. When linked together the foglets would form an Octet truss. The foglets' bodies would be made of Aluminium oxide rather than combustible diamond to avoid creating fuel air explosives. This Technology is going to have a very sound effect on future and the researches are going on this technology to make it more compatible and sophisticated. So in the future Of about twenty years from now it is expected to be in a very good operating mode with Many of the flaws being eliminated and we could see the wonders which can be done byte nanotechnology.
Chapter 11
REFERENCES 1. Eric Drexler - "Nanosystems: Molecular Machinery, Manufacturing and Computation" Vol.1; 2002; pp.564-569 2. J Storrs Hall- “Towards Instant Manufacturing” 3. Rutgers – "Utility Fog- The Stuff that Dreams are made of": Vol.1;2005 4. Susan Stepney – “Scalable, (Non-) Evolvable, Emergent, Developmental
Nanotechnology”; 2003; pp.6-7. 5. Site : http://www.kurzweilai.net/meme/frame.html?main=/articles/art0220.html 6. Site : http://www.pivot.net/~jpierce/aspects_of_ufog.htm DEPT. OF MECHANICAL ENGINEERING ENGINEERING,TRIVANDRUM
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7. Site : http://www.wildirisdesign.com/nano/ufog.html 8. Site: http://www. nanotech-now/utility-fog.htm
9. Journal:http://www.aeiveos.com/~bradbury/Authors/Computing/HallJS/UFAUPS.html
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