Your SlideShare is downloading. ×
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Nanotechnology
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Nanotechnology

5,551

Published on

seminar report

seminar report

Published in: Education, Technology, Business
1 Comment
2 Likes
Statistics
Notes
No Downloads
Views
Total Views
5,551
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
664
Comments
1
Likes
2
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Seminar Report on NANOTECHNOLOGY Submitted in partial fulfillment of the requirement for the degree of B.Tech-8th Semester In Information And TechnologySubmitted to Submitted byMrs. Shabnam Khan Sanchit SharmaLecturer(CSE/IT) B.Tech (IT) 8th-Sem.Department of Computer Science & Engineering Applied College of Management & Engineering 72-Km Stone, Delhi-Mathura Road, Mitrol, Palwal-Haryana www.acmecollege.in
  • 2. AcknowledgementThe confidence one attains while performing a task that has great importance of its owncomes not only through one’s own constant efforts but rather is a result of ceaselesscooperation, constant guidance and ever motivating tips of various experienced people.I express my sincere gratitude to HOD Jatin Verma for his guidance and especially for hisemphasis on systematic approach, details and rigor in the process of research. I cherish thediscussions I had with him and thank him for his advice and all the support throughout myresearch work.I am grateful to Mrs. Shabnam Khan for her guidance and especially, for her constantencouragement for developing a deep passion towards research and emphasis on hard workand rigorous experimentation.I would also like to thank the faculty members of the my institute with whom I had fruitfulinteractions. Sanchit Sharma 2
  • 3. AbstractFor many decades, nanotechnology has been developed with cooperation from researchers inseveral fields of studies including physics, chemistry, biology, material science, engineering, andcomputer science. Nanotechnology is engineering at the molecular (groups of atoms) level. It isthe collective term for a range of technologies, techniques and processes that involve themanipulation of matter at the smallest scale (from 1 to 100 nm2).The nanotechnology providesbetter future for human life in various fields. In future nanotechnology provides economy, ecofriendly and efficient technology which removes all difficult predicaments which is faced by usin today life scenario. Nanotechnology is the technology of preference to make things small,light and cheap, nanotechnology based manufacturing is a method conceived for processing andrearranging of atoms to fabricate custom products.The nanotechnology applications have three different categories nanosystems, nanomaterials andnanoelectronics. The impact of the nanotechnology occurred on computing and data storage,materials and manufacturing, health and medicine, energy and environment, transportation,national security and space exploration. There are many applications of nanotechnology whichare exciting in our life such as nanopowder, nanotubes, membrane filter, quantum computers etc.But there are several problems which are occurred with the exploration of the nanotechnologysuch as the wastes released while making the materials for nanotechnology are released into theatmosphere and can even penetarte human and animal cells and effect their performance,agricultural countries will lose their income as nanotechnology will take over, if any damage isdone at the molecular level then it is not possible to revert it. 3
  • 4. CONTENTS1. Introduction to Nanotechnology………………………………….... 042. History of Nanotechnology….…………………………………….....053. Concept……………………………………………………………… 06 3.1 A material perspective……………………………………06 3.2 Nano Mechanics and bio materials. ……….……………074. Nanotechnology Tools………………………………………………08 4.1 Transmission Electron Microscope (TEM)…………………..08 4.2 Atomic Force Microscope (AFM)…………………………….08 4.3 Scanning Tunneling Microscope (STM)……………………..095. Future Nanotechnology Applications……………………………....106. Exciting Applications of Nanotechnology..................................…...14 6.1 Nanopowders………………………………………………….14 6.2 Membranes……………………………………………………15 6.3 Carbon Nanotube……………………………………………..16 6.4 Molecular electronics…………………………………………17 6.5 Quantum Computers…………………………………………17 6.6 NanoRobotics………………………………………………….187. Conclusion…………………………………………………………..198. References …………………………………………………………………...20 4
  • 5. Chapter 1 IntroductionNanotechnology is engineering at the molecular (groups of atoms) level. It is the collective termfor a range of technologies, techniques and processes that involve the manipulation of matter atthe smallest scale from 1 to 100 nm2 (1 nm = 0.000000001 m).The classical laws of physics and chemistry do not readily apply at this very small scale for tworeasons. Firstly, the electronic properties of very small particles can be very different from theirlarger cousins. Secondly, the ratio of surface area to volume becomes much higher, and since thesurface atoms are generally most reactive, the properties of a material change in unexpectedways. For example, when silver is turned into very small particles, it takes on anti-microbialproperties while gold particles become any colour you choose. Nature provides plenty ofexamples of materials with properties at the nanoscale – such as the iridescence of butterflywings, the sleekness of dolphin skin or the ‘nanofur’ that allows geckos to walk up verticalsurfaces.Nanotechnology is not confined to one industry, or market. Rather, it is an enabling set oftechnologies that cross all industry sectors and scientific disciplines. Probably uniquely, it isclassified by the size of the materials being developed and used, not by the processes being usedor products being produced. Nanoscience is inherently multidisciplinary: it transcends theconventional boundaries between physics, chemistry, biology, mathematics, informationtechnology, and engineering. This also means it can be hard to define – is the introduction offoreign genes or proteins into cells biotechnology or nanotechnology? And since genes havegenetic memory, might this also be a form of information technology? The answer is probably‘all of the above’. The important point is that the integration of these technologies and theirmanipulation at the molecular and sub-molecular level will over the next decade provide majoradvances across many existing industries and create whole new industries. 5
  • 6. Chapter 2 HistoryRichard Feynman, US physicist and Nobel Prize winner, presented a talk to the AmericanPhysical Society annual meeting entitled There’s Plenty of Room at the Bottom. In his talk,Feynman presented ideas for creating nanoscale machines to manipulate, control and imagematter at the atomic scale. Prof. Feynman described such atomic scale fabrication as a bottom-up approach, as opposed to the top-down approach that we are accustomed to. Top-downmanufacturing it involves the construction of parts through methods such as cutting, carving andmolding. Using these methods, we have been able to fabricate a remarkable variety of machineryand electronics devices. Bottom-up manufacturing would provide components made of singlemolecules, which are held together by covalent forces that are far stronger than the forces thathold together macro-scale components. Further more, the amount of information that could bestored in devices build from the bottom up would be enormous. In 1974, Norio Taniguchi introduced the term ‘nanotechnology’ to represent extra-highprecision and ultra-fine dimensions, and also predicted improvements in integrated circuits,optoelectronic devices, mechanical devices and computer memory devices. This is the so called‘top-down approach’ of carving small things from large structures. In 1986, K. Eric Drexler inhis book Engines of Creation discussed the future of nanotechnology, particularly the creation oflarger objects from their atomic and molecular components, the so called ‘bottom-up approach’.He proposed ideas for ‘molecular nanotechnology’ which is the self assembly of molecules intoan ordered and functional structure.The invention of the scanning tunneling microscope by Gerd Binnig and Heinrich Rohrer in1981 (IBM Zurich Laboratories), provided the real breakthrough and the opportunity tomanipulate and image structures at the nanoscale. Subsequently, the atomic force microscopewas invented in 1986, allowing imaging of structures at the atomic scale. Another majorbreakthrough in the field of nanotechnology occurred in 1985 when Harry Kroto, Robert Curland Richard Smalley invented a new form of carbon called fullerenes (‘buckyballs’), a singlemolecule of 60 carbon atoms arranged in the shape of a soccer ball. This led to a Nobel Prize inChemistry in 1996.Since that time, nanotechnology has evolved into one of the most promising fields of science,with multi-billion dollar investments from the public and private sectors and the potential tocreate multi-trillion dollar industries in the coming decade. 6
  • 7. Chapter 3 Concept Of NanotechnologyAtoms and molecules stick together because they have complementary shapes that lock together,or charges that attract. Just like with magnets, a positively charged atom will stick to a negativelycharged atom. As millions of these atoms are pieced together by nanomachines, a specificproduct will begin to take shape. The goal of molecular manufacturing is to manipulate atomsindividually and place them in a pattern to produce a desired structure.The first step would be to develop nanoscopic machines, called assemblers, that scientists canprogram to manipulate atoms and molecules at will. Rice University Professor Richard Smalleypoints out that it would take a single nanoscopic machine millions of years to assemble ameaningful amount of material. In order for molecular manufacturing to be practical, you wouldneed trillions of assemblers working together simultaneously. Eric Drexler believes thatassemblers could first replicate themselves, building other assemblers. Each generation wouldbuild another, resulting in exponential growth until there are enough assemblers to produceobjects.Nanotechnology is not confined to one industry, or market. Rather, it is an enabling set oftechnologies that cross all industry sectors and scientific disciplines. Probably uniquely, it isclassified by the size of the materials being developed and used, not by the processes being usedor products being produced. Nanoscience is inherently multidisciplinary: it transcends theconventional boundaries between physics, chemistry, biology, mathematics, informationtechnology, and engineering. This also means it can be hard to define – is the introduction offoreign genes or proteins into cells biotechnology or nanotechnology? And since genes havegenetic memory, might this also be a form of information technology? The answer is probably‘all of the above’. The important point is that the integration of these technologies and theirmanipulation at the molecular and sub-molecular level will over the next decade provide majoradvances across many existing industries and create whole new industries.3.1 A material perspectiveOn of the fundamental concept which is the ground basis for nanotechnology is the materialperspective. Before the advent of nanotechnology material was not seen atomically. Scientistsstarted decomposing large materials to from new components from them. it has been observedthat decomposition of a materials at nano scale changes its properties. For example scanningtunneling microscopy. Number of mechanical and physical phenomena which appears whensystem size is decreased these affects are known as mechanical effect or quantum size effects.Where as the electronic characteristics of solids are altered with great decrease in particle size.This effect does not come into play by going from macro to micro dimensions of materials. butwhen micro to macro size reduction was performed this affect become dominant when molecularsize of the particle is reached. Electrical, optical, and magnetic properties of the materialschanged at nanoscale rearrangements 7
  • 8. 3.2 Nano Mechanics and bio materials.The concept of nanomechanics was also originated when new chemical properties of conductorsand semi conductors were found. Nano materials empowered the production of new devices butat the same time it also opened the potential risks in their reactions with biomaterials. Materialsexhibit different properties as they exhibited at macro level which enabled unique applications totake place for example opaque elements become transparent such as copper, insulators becomeconductor at nano scale treatment like silicon, solid can be converted into liquid at normal roomtemperature such as gold. Bottom line is that nanotechnology totally transformed the entirestructure of any substance into new architecture.3.3 Molecular perspective (simple to Complex)Advanced chemistry has reached the level where it can produce molecules for almost everystructure of the present world. these techniques are used to prepare wide range of chemicalcompounds such as polymers and pharmaceuticals but the extension of the control gives birth tothe question that how these molecules could be reassemble into more advanced super molecularassemblies. Molecular self assembly in gradually evolving into supramolecular chemistry tomake the new components which can reassembles themselves.3.4 Molecular RecognitionAnother important concept is the molecular recognition which is one of the fundamentalconcepts of nanotechnology. Molecular rearranges them selves chemically by molecularrecognition. There is special force that is present between molecules non covalent intermolecularforce which supports the conformation of chemical similarity of molecules.Chapter 4 8
  • 9. Tools In NanotechnologyThe main tools used in nanotechnology are three main microscopes:-(i) Transmission Electron Microscope (TEM)(ii) Atomic Force Microscope (AFM)(iii) Scanning Tunneling Microscope (STM)4.1 Transmission Electron Microscope (TEM)The transmission electron microscope is one that utilizes a high-energy electron beam thatprobes sample materials with a thickness less than 100 nanometers (nm). While some electronsare either absorbed or bounced of the material, others pass through it creating a magnified imageas the one shown in the example. Current TEMs use digital cameras placed behind the materialto capture and record images, magnifying images up to 30 million times. The TEM is the mostpopular microscope used the make images published in scientific journals on nanocrystals foundin semiconductors.4.2 Atomic Force Microscope (AFM)The atomic force microscope (AFM) uses a small silicon tip as a probe to make images ofsample material. While the probe move along the surface of the sample, the electrons of theatoms in the material begin to repel the electrons of the probe. The AFM then adjusts the heightof the probe to keep the force of the sample constant. A mechanism records the movement of theprobe and sends this information to a computer that will generate a three-dimensional image asshown in the slide. The image will show the exact topography of the surface. 9
  • 10. 4.3 Scanning Tunneling Microscope (STM)A scanning tunneling microscope (STM) uses a wavelike property of electrons known astunneling, which allows electrons emitted from a probe to penetrate, or tunnel into, the surface ofthe examined object. The electrons generate a tiny electric current that the STM measures.Similar to the atomic force microscope, the height of the probe in the STM is adjusted constantlyto keep the current constant. In doing, so a detailed map of the material’ surface is produced asthe example in this slide shows. 10
  • 11. Chapter 5 Nanotechnology ApplicationsNanotechnology opens the way towards new production routes, towards new, moreefficient, performance and intelligent materials, towards new design of structures andrelated monitoring and maintenance systems.The various applications of nanotechnology in different fields are as follows:-(i) Computing and Data Storage(ii) Materials and Manufacturing(iii) Health and Medicine(iv) Energy and Environment(v) Space Exploration5.1 Computing and Data StorageAs the ever-increasing power of computer chips brings us closer and closer to the limits ofsilicon technology, many researchers are betting that the future will belong to “spintronics”: ananoscale technology in which information is carried not by the electron’s charge, as it is inconventional microchips, but by the electron’s intrinsic spin. If a reliable way can be found tocontrol and manipulate the spins, these researchers argue, spintronic devices could offer higherdata processing speeds, lower electric consumption, and many other advantages overconventional chips–including, perhaps, the ability to carry out radically new quantumcomputations.Now, University of Notre Dame physicist Boldizsar Janko and his colleagues believe they havefound such a control technique. Their work, funded by the National Science Foundation througha Nanoscale Interdisciplinary Research Team grant, was published in the March 5, 2005, editionof the journal Nature.The idea is to create the device as a series of layers, each only a few dozen nanometers thick. Atthe base is a layer of diluted magnetic semiconductor, a type of material Janko and his grouphave been studying intensively. When gallium arsenide is doped with manganese atoms, forexample, each manganese atom contributes an extra electron, and thus an extra electron spin; theresult is a semiconductor material that can be magnetized in much the same way as iron. Then aninsulator material is layered over the base, followed by a layer of superconducting material.Next, a magnetic field is applied perpendicular to the top surface (see animation above). Thanksto the basic physics of superconductors, the field can make it through only by pinching itselfdown into an array of nanoscale flux tubes. That super concentrates the field inside each tube, sothat it creates a spot of high-intensity magnetism on the semiconductor layer below, which, in 11
  • 12. turn, creates a patch of closely aligned electron spins. The resulting spin patches, one for eachflux tube, are then available for encoding information.The effect resembles what happens when you sprinkle iron filings on a piece of paper, and thenhold a bar magnet underneath, says Janko: the presence of the magnet (the flux tube) makes theiron filings (the spins) stand at attention. Furthermore, he says, just as you can manipulate thefilings by moving the magnet underneath the paper, you can manipulate the spins in this systemby moving the flux tubes. For example, an electric current flowing through the superconductorwill cause a given flux tube to move to one side (with the patch of spins underneath movingalong with it), while a current flowing in the reverse direction will move it back to the other side(see animation, this video requires the free RealPlayer plug-in).5.2 Materials and ManufacturingThe Nanotechnology, Advanced Materials and Manufacturing (NM) topic addresses innovationsand development of new materials, devices, machines, structures and manufacturing processesfor the advancement of the competitive nature. NM includes materials and manufacturingtechnologies such as electronic materials and processes, high temperature materials, structuralmaterials, coatings, composites, powder processing, nanomanufacturing, printing, patterning andlithography, machining, casting, joining, additive manufacturing, self-assembly, and otherrelated research areas.The NM program seeks to support high-risk, high-payoff innovative technologies with thepotential for large impact on business, consumers, and society, thereby catalyzing new businessopportunities for small businesses in todays global marketplace. NSF is committed to supportingscientific discoveries to benefit society and to emphasize private sector commercialization.Novel technologies aimed at achieving increased performance, reduced cost, and/or newfunctions or applications are of great interest.5.3 Health and Medicine 12
  • 13. Nanomedicine: NBM is an international, peer-reviewed journal presenting novel, significant,and interdisciplinary theoretical and experimental results related to nanoscience andnanotechnology in the life sciences. Content includes basic, translational, and clinical researchaddressing diagnosis, treatment, monitoring, prediction, and prevention of diseases. In additionto bimonthly issues, the journal website (click here) also presents important nanomedicine-related information, such as future meetings, meeting summaries, funding opportunities, societalsubjects public health, and ethical issues of nanomedicin e .The potential scope of nanomedicine is broad, and we expect it to eventually involve all aspectsof medicine. Sub-categories include synthesis, bioavailability, and biodistribution ofnanomedicines; delivery, pharmacodynamics, and pharmacokinetics of nanomedicines; imaging;diagnostics; improved therapeutics; innovative biomaterials; interactions of nanomaterials withcells, tissues, and living organisms; regenerative medicine; public health; toxicology; point ofcare monitoring; nutrition; nanomedical devices; prosthetics; biomimetics; and bioinformatics.5.4 Energy And EnvironmentDevelopment of new energy technologies and technologies for a cleaner environment are twoimportant focus areas. For example, the development of light and strong new materials wouldmake planes, trains and cars lighter and thus reduce energy consumption. Development ofeffective methods for the conversion of one type of energy to another is another important area.Materials with new functional properties will be able to streamline the energy conversion, forexample from sunlight to electricity in solar cells, or from electrical energy to chemical energy inthe form of hydrogen gas. The production of new and effective nanomaterials will also providean environmental benefit because the material need will be less than with the use of traditionalmaterials.Choosing the main profile of “Nanotechnology for materials, energy and environment” you willcontribute to the development of such new environmental friendly energy technologies. You willalso be able to contribute to the development of for example new, effective methods forpurifying gases, liquids and drinking water as well as separating CO2 for storage. In order to 13
  • 14. avoid possible negative effects, it is also crucial to understand the impact new nanomaterials willhave on the environment. A specialisation within “Nanotechnology for materials, energy andenvironment”, will equip in facing the worlds climate challenges.5.5 Space Exploration NASA and other researchers are exploring the use of carbon based Nanotubes to deliversolutions for some of its most promising visions of space exploration. This includes suchapplications as a huge space elevator which can carry cargo to and from earth without the needfor orbital takeoff and landing. Nanotechnology is also being considered for other applications aswell, such as solar sail applications that can be used to propel spacecraft using light from the sun,ion thrusters that replace chemical rockets, and materials that can be used to make the outside ofspacecraft resilient to bombardment from space debris. The great space elevator concept has been the subject of much fascination and imagination,and it no doubt faces a host of engineering challenges. The idea is to create a long cable from theEarth to space, tethering the cable to an object in orbit—such as an asteroid in space—andanchoring it on Earth to a station that is rigged in the ocean somewhere. Cargo can then beshuttled back and forth without the need for rockets and fuel as the transport mechanism. Thecable would extend to 90,000 kilometers in length, be constructed of carbon based Nanotubes,and use solar power to generate the electricity needed to shuttle it back and forth from space.NASA’s Institutes for Advanced Concepts and the Elevator 2010 group provide insights andyearly competitions to accelerate the time to production of the first successful prototype. Nanotechnology is also being considered for use with space craft as well. One such use comesin the form of solar sails. These use electricity from the sun to power a spacecraft’s travels,rather than relying on thruster engines. Researchers have used carbon based Nanotubes to createthe thin sheets used as the space sails. And to replace chemical rockets altogether, ion thrusterscan use solar cells to generate electric fields as the propulsion mechanism. Additionally, otherresearchers have explored the possibility of using Nanotubes for the exterior of the spaceshipitself, to create a resilient exterior that can withstand space debris bombardment. Ultimately, itwill even be possible to use Nanoparticles to effect any necessary repairs to the ship’s hull.Chapter 6 Exciting Applications of Nanotechnology 14
  • 15. 6.1 Nanopowders – building blocks of nanomaterialsNanopowders contain particles less than 100 nm in size — 1/10,000th the thickness of a humanhair. The physical, chemical and biological properties of such small particles allow industry toincorporate enhanced functionalities into products.Some of the unique properties of interest to industry are enhanced transparency from particlesbeing smaller than the wavelength of visible light, and high surface areas for enhancedperformance in surface area-driven reactions such as catalysts and drug solubilisation.These unique properties give rise to a range of new and improved materials with a breadth ofapplications. For example, nanotechnology allows plastics to retain transparency while alsotaking on characteristics such as resistance to abrasion, conductivity or UV protection found inceramics or metals. New medical nanomaterials are being developed, such as synthetic bone andbone cement, as well as drugs with improved solubility to allow lower dosing, more efficientdrug delivery and fewer adverse side effects.The high surface areas of nanoparticles are being exploited by industry in catalysts that improvechemical reactions in applications such as cleaning up car exhausts and potentially to removetoxins from the environment. For example, petroleum and chemical processing companies areusing nanostructured catalysts to remove pollutants — $30 billion industry in 1999 with thepotential of $100 billion per year by 2015. Improved catalysts illustrate that improvements toexisting technology can open up whole new markets — nanostructured catalysts look likely to bea critical component in finally making fuel cells a reality, which could transform our powergeneration and distribution industry.6.2 MembranesNanotechnology can address one of the most pressing issues of the 21st Century — safe, cleanand affordable water. There are 1.3 billion people without access to safe drinking water and 15
  • 16. indications are that global consumption of water will likely double in the next 20 years. Freshwater supplies are already limiting the growth of our cities — Australian cities such asSydney and Perth are considering waste water reuse schemes to augment their water supplies,London is investing ₤200 million in desalination and Singapore recycles wastewater. Furthertechnology development is required to make this cost effective and allow it to become a moremainstream water supply option.Nanomembrane filtration devices that ‘clean’ polluted water, sifting out bacteria, viruses, heavymetals and organic material, are being explored by research teams in the US, Israel and Australia(at the UNESCO Centre for Membrane Science and Technology at the University of New SouthWales and a consortium of CSIRO Divisions). The key to lowering the energy demand andimproving throughput for desalination is in understanding how to selectively separate smallmolecules, and package these technologies for exploitation. Separation of molecules occursefficiently in nature through membranes, such as the ion channels that remove salt from bloodand the respiratory membranes that transport oxygen and carbon dioxide. In order to reduce theenergy requirement for this process, nature provides large surface areas for the transport ofmolecules. A parallel approach is being developed by nanotechnologists for the production ofnanoarchitectures for cost-effective filtration systems in large-scale water purification.6.3 Carbon NanotubeCarbon nanotubes possess many unique properties which make them ideal AFM probes. Theirhigh aspect ratio provides faithful imaging of deep trenches, while good resolution is retained 16
  • 17. due to their nanometer-scale diameter. These geometrical factors also lead to reduced tip-sampleadhesion, which allows gentler imaging. Nanotubes elastically buckle rather than break whendeformed, which results in highly robust probes. They are electrically conductive, which allowstheir use in STM and EFM (electric force microscopy), and they can be modified at their endswith specific chemical or biological groups for high resolution functional imaging. ProfessorCharles M. Lieber GroupCNT exhibits extraordinary mechanical properties: the Youngs modulus is over 1 Tera Pascal. Itis stiff as diamond. The estimated tensile strength is 200 Giga Pascal. These properties are idealfor reinforced composites, nanoelectromechanical systems (NEMS)Carbon Nanotube Transistors exploit the fact that nm- scale nanotubes (NT) are ready-mademolecular wires and can be rendered into a conducting, semiconducting, or insulating state,which make them valuable for future nanocomputer design. Carbon nanotubes are quite popularnow for their prospective electrical, thermal, and even selective-chemistry applications. PhysicsNews 590, May 21, 2002Many potential applications have been proposed for carbon nanotubes, including conductive andhigh-strength composites; energy storage and energy conversion devices; sensors; field emissiondisplays and radiation sources; hydrogen storage media; and nanometer-sized semiconductordevices, probes, and interconnect. Some of these applications are now realized in products.Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded bycontroversy. Nanotube cost, polydispersity in nanotube type, and limitations in processing andassembly methods are important barriers for some applications of single-walled nanotubes.6.4 Molecular electronics — cross bar latches to replace silicon chipsHewlett-Packard — one of the worlds biggest computer companies — declared on 1 February2005 that it is on the verge of a revolution in computer chip technology10. They believe thatsilicon computer chips will have reached a technical dead end in about a decade, to be replaced 17
  • 18. by tiny nanotechnology devices described as ‘cross bar latches’. These molecular-scalealternatives to the transistor should dramatically improve the performance of computers becausethey are much smaller — only 2 or 3 nm in size compared with 90 nm for transistors — and theycan store memory for much longer periods.The new device consists of a wire that is crossed by two other wires. The resulting junctionsserve as switches that are only a few atoms across and can be programmed by a repeatable set ofelectrical pulses.6.5 Quantum ComputersThe quantum computer uses quantum particles as the "tape" in the Turing experiment. Becausethe presence of a symbol or a blank in the Turing tape symbolizes the binary digits, so can thestate of the quantum particles be used to hold these values. The use of multiple quantum particlesalso means that the quantum computer will be much faster than the Turing machine since it canperform several calculations simultaneously.Moreover, unlike todays computers that uses the basic bit which has only two states (1 or 0), aquantum computer will store information as quantum bits which can hold more than two values.This ability of qubits to exist in more than two states means that a quantum computer has thecapability of performing more than a million simultaneous computations at one time and thepotential to be a lot faster and a lot more powerful than todays supercomputers.Quantum computers will also be able to utilize one other important characteristic of quantumparticles known as entanglement. The property of entanglement makes it possible to assign anddetermine the value or the spin of a quantum particle by introducing an outside force.6.6 NanoRoboticsBasic nanomachines are already in use.Nanobots will be the next generation of nanomachines. Advanced nanobots will be able to senseand adapt to environmental stimuli such as heat, light, sounds, surface textures, and chemicals;perform complex calculations; move, communicate, and work together; conduct molecularassembly; and, to some extent, repair or even replicate themselves. Nanobot.info is an 18
  • 19. informational site that provides information on both recent developments and future applicationsat the intersection of nanotechnology and robotics. Nanotechnology is the science andapplication of creating objects on a level smaller than 100 nanometers. The extreme concept ofnanotechnology is the "bottom up" creation of virtually any material or object by assembling oneatom at a time. Although nanotech processes occur at the scale of nanometers, the materials andobjects that result from these processes can be much larger. Large-scale results happen whennanotechnology involves massive parallelism in which many simultaneous and synergisticnanoscale processes combine to produce a large-scale result. Conclusion 19
  • 20. Nanotechnology offers the ability to build large numbers of products that are incredibly powerfulby todays standards. This possibility creates both opportunity and risk. The problem ofminimizing the risk is not simple; excessive restriction creates black markets, which in thiscontext implies unrestricted nanofabrication. Selecting the proper level of restriction is likely topose a difficult challenge.This paper describes a system that allows the risk to be dealt with on two separate fronts: controlof the molecular manufacturing capacity, and control of the products. Such a system has manyadvantages. A well-controlled manufacturing system can be widely deployed, allowingdistributed, cheap, high-volume manufacturing of useful products and even a degree ofdistributed innovation. The range of possible nanotechnology-built products is almost infinite.Even if allowable products were restricted to a small subset of possible designs, it would stillallow an explosion of creativity and functionality.Preventing a personal nanofactory from building unapproved products can be done usingtechnologies already in use today. It appears that the nanofactory control structure can be madevirtually unbreakable. Product approval, by contrast, depends to some extent on humaninstitutions. With a block-based design system, many products can be assessed for degree ofdanger without the need for human intervention; this reduces subjectivity and delay, and allowspeople to focus on the few truly risky designs.In addition to preventing the creation of unrestricted molecular manufacturing devices, furtherregulation will be necessary to preserve the interests of existing commercial and militaryinstitutions. For example, the effects of networked computers on intellectual property rights havecreated concern in several industries, and the ability to fabricate anything will surely increase theproblem. National security will demand limits on the weapons that can be produced. References 20
  • 21. 1. www.slideshare.net2. www.amazon.com3. www.thinkgos.com/cloud/index.html4. www.salesforce.com5. www.google.com 21

×