Magnetic properties

Bulk gold and Pt are non-magnetic, but at the nano size they are magnetic. Surface atoms not only are different to bulk atoms, but they can also be modified by interaction with other chemical species, that is, by capping the nanoparticles. This phenomenon opens the possibility to modify the physical properties of the nanoparticles by capping them with appropriate molecules. Actually, it should be possible that non-ferromagnetic bulk materials exhibit ferromagnetic-like behavior when prepared in nano range. One can obtain magnetic nanoparticles of Pd, Pt and the surprising case of Au (that is diamagnetic in bulk) from non-magnetic bulk materials. In the case of Pt and Pd, the ferromagnetism arises from the structural changes associated with size effects. However, gold nanoparticles become ferromagnetic when they are capped with appropriate molecules: the charge localized at the particle surface gives rise to ferromagnetic-like behavior.

Surface and the core of Au nanoparticles with 2 nm in diameter show ferromagnetic and paramagnetic character, respectively. The large spin-orbit coupling of these noble metals can yield to a large anisotropy and therefore exhibit high ordering temperatures. More surprisingly, permanent magnetism was observed up to room temperature for thiol-capped Au nanoparticles. For nanoparticles with sizes below 2 nm the localized carriers are in the 5 d band. Bulk Au has an extremely low density of states and becomes diamagnetic, as is also the case for bare Au nanoparticles. This observation suggested that modification of the d band structure by chemical bonding can induce ferromagneticlike character in metallic clusters.

SPR dependencies and colour

The angle at which surface plasmon resonance occurs mainly depends on the nature of the metal, the wavelength of the incident light and the refractive index of the medium on either side of the metal surface. Because the refractive index is sensitive to temperature, it is important to perform the measurements at defined temperatures. In some cases, this dependency can be exploited. The metal must have conduction band electrons capable of resonating with the incoming light at a suitable wavelength. Metals that satisfy this condition are silver, gold, copper, aluminum, sodium and indium. In addition, the metal surface must be free of oxides, sulphides and not react with other molecules on exposure to the atmosphere or liquid. Of the metals, indium is too expensive, sodium is too reactive, copper and aluminum are too broad in their SPR response and silver is too susceptible to oxidation. This leaves gold as the most practical metal. Gold is resistant to oxidation and other atmospheric contaminants, but it is compatible with a lot of chemical modification systems. The light source should be monochromatic and p-polarized (polarized in the plane of the surface) to obtain a sharp dip as shown in

Enhanced strength and toughness

The strength and toughness of both ceramics and metals can be enormously enhanced if they are made out of nanoscale crystallites rather than the usual micron-sized grains. This effect is already widely exploited to make superior ceramics and tungsten carbide-cobalt composites. Ceramics made from nanoscale TiO2 particles not only sinter together even at 600°C, but also possess enhanced strength and toughness. There is a similar effect in metal systems. Nanocrystalline copper, for example, is up to five times stronger than ordinary copper. In this case, the explanation relies upon the observation that deformation in metals is generally carried by lattice defects called dislocations, and nanoscale copper crystals are actually too small to even contain dislocations. Aluminum also shows the same effect. A process called as equiangular extrusion is used to refine the grain size of the aluminum into the nanoscale, so that it will be hard and lose the ductility. Similar behavior is exhibited by gold.

Electronic configurations

Bulk gold is a renowned conductor of electricity, with a conductivity value that is beaten only by copper and silver. This property arises directly from its electronic configuration. However, even this familiar ‘fact’ is overturned at the nanoscale. Gold structures at the bottom end of the nanoscale may, depending on shape and substrate, actually be semiconductor with a significant value of band gap.

The transition occurs somewhere between 1 and 3 nm, corresponding to a hemispherical cluster containing between 15 and 150 atoms. The special electronic configuration of small nanoparticles results, from the fact that their physical dimensions are smaller than the characteristic dimension of the electron wave function of the bulk material. Such tiny particles, termed as quantum dots or artificial atoms if they are disc-shaped, have been proposed as the basis of a new generation of nanoscale electronic devices. Recently the electronic properties of gold nanoparticles have been examined on the basis of density functional theory (DFT). They have shown that for Au8 , the energy difference between HOMO and LUMO is highest and the frontier wave function has considerable mixing of s and d character. The catalytic activities of such exceedingly small clusters have been found to be acutely size dependent, peaking in one example at a cluster diameter of close to 3 nm, and falling sharply within 0.5 nm either side . One interpretation of this is that the best catalytic activity is actually derived from a particular value of the band gap, and too great a gap, or none at all, is less favorable. It should be noted that gold is not unique in this respect, and that other noble metals, such as Pd and Pt, exhibit similar properties.

Surface plasmon resonance and colour

The optical properties of these Au and Ag nanoparticles are interesting. The colour of the metal nanoparticles is mainly based on the surface plasmon resonance. Surface Plasmon Resonance (SPR) is a physical process that can occur when planepolarized light hits a metal film under total internal reflection conditions. But SPR is confined to Au, Ag, Cu and alkali earth metals. It is accounted with the presence of loosely bound conduction electron present in these elements.

Gold, Silver and Platinum Nanomaterials

Introduction

Metal nanomaterials have received considerable attention in the last decade in science and technology. The nature and behavior of the metal nanomaterials are different from that of the bulk material. Metal nano particles find wide application in various fields. Metals are unique in their physical and chemical properties as compared to other compound materials such as metal oxides, sulphides and nitrides. Metals have ductility, malleability, luster, high density, fewer defects and are generally crystalline in nature. Though the metal nanoparticles were synthesized and used from the ancient days even in the era of the Alchemists, lack of enough characterization techniques such as electron microscopes has left the nanoscience unexplored till recently.

In ancient days, the only characterization of metal nanoparticles is naked eye. The colouring nature of Au and Ag nanoparticles was fundamental identification for their nanoparticle colloid formation. Making use of this, they have been used as coloring agents in decorative glasses and clothing. This is due to light-absorbing nature of the surface of Au and Ag nanoparticles because of the surface plasmon resonance. Pt nanoparticles are catalytically active for oxidation and reduction reactions. As a result, these nanomaterials find applications for catalytic use. Since Au, Ag and Pt nano particles have considerable stability as compared to other metals, they have gained importance. However, in the near future, all metals will be possibly shaped in nanosize by using suitable stabilizing agents and medium. In this chapter nature and applications of the nanomaterial of chosen metals are described. However, closer to each other in the periodic table, the physical properties of the nanosize materials of these metals vary drastically. To begin with, it is essential to comprehend fundamental properties of these (Ag, Au and Pt) metals.

Light emitting diode materials

GaN based lighting

GaN based lighting has potential to give a huge financial reward all over the world. The penetration of GaN based LED lighting to all lighting applications would imply a major improvement in efficiency and this would reduce the world power consumption by ~1000 TWh pa. with 10 % of world energy worth $100 bn used to produce light, efficiency savings would have a major impact on energy efficiency. Replacement of car headlights, fluorescent tubes, and street lights require the quality of white LEDs to improve - if white LEDs were as efficient as current red ones, all lights would be replaced. Other nano materials in light emitting devices which are used in the communication sector are GaN, GaAlAs, GaAs, InGaAsP, and GaP, AlAs etc. Among nano organic LED’s Poly [2- methoxy-5-(2’-) ethylhexyloxy)-1, 4-Phenylenevinylene] (MEH-PPB) is one example. Liquid Crystals as well as having applications in displays have potential applications for improving switching speeds in telecoms by replacement of silicon. They also have potential as photonic materials leading to improved optical materials with higher resolution. LCDs continue to develop and underpin many applications – laptops, mobile phones, etc. Constant advances are being made in low power-consumption devices and displays. Further to this, development of non-display applications is becoming increasingly important: e.g. lasing and photonics, telecoms, biology / medicine, control of microwaves. Soap is an example of liquid crystal. Cyanophenyl materials, fluorinated tolans, biological membranes, phospholipids and the protein solution that is extruded by the spider to generate silk is a liquid crystal phase.

Carbon nanotube emitters

Standard electron emitters are based either on thermionic emission of electrons from heated filaments with low work functions or field emission from sharp tips. The latter generates monochromatic electron beams; however, ultrahigh vacuum and high voltages are required. Further the emission current is typically limited to several micro amperes. Carbon fibers typically 7 μm in diameters have been used as the electron emitters; however they suffer from poor reproducibility and rapid deterioration of the tip. Carbon nano tubes have high aspect ratios and small tip radius of curvature. The ability to emit electrons from the body of nano tubes was attributed to the small radius of the tubes and the presence of defects on the surface of carbon nano tubes. VII. Wireless communication Most of the communication systems are either based on radio frequency or on microwave. If proven to be effective, nano-materials will eventually replace the current materials used in all these devices. NTT Electronics Corporation has endeavored to commercialize new laser emission sources that are optimum for next-generation communication systems and applications in non-communication fields such as medicine and the environment. Wireless is an old-fashioned term for a radio receiver, referring to its use as a wireless telegraph; now the term is used to describe modern wireless connections such as in cellular networks and wireless broadband Internet.

A wireless LAN or WLAN is a wireless local area network that uses radio waves as its carrier. The backbone network usually uses cables, with one or more wireless access points connecting the wireless users to the wired network. Materials in its nano form show peculiar electric and magnetic properties. Hence nanomaterials are incorporated into wireless LAN systems to attain a magnetic resonance of suitable frequency.

Molecular switches for communication sectror

The principle is to insert in the structure of a mixed valence compound a molecular bridge with two possible states: "ON" (i.e. a non-zero electronic coupling between extremities), and "OFF" (i.e. no coupling). Thus we monitor the photo induced electron transfer process where an electron moves from one end to the other of the molecule.

Alternative materials and operating principles for the elaboration and communication of data in electronic circuits and optical networks must be identified. Organic molecules are promising candidates for the realization of future digital processors. Their attractive features are the miniaturized dimensions and the high degree of control on molecular design possible in chemical synthesis. Indeed, nanostructures with engineered properties and specific functions can be assembled relying on the power of organic synthesis. In particular, certain molecules can be designed to switch from one state to another, when addressed with chemical, electrical, or optical stimulations, and to produce a detectable signal in response to these transformations. Binary data can be encoded on the input stimulations and output signals employing logic conventions and assumptions similar to those ruling digital electronics.

Thus, binary inputs can be transduced into binary outputs relying on molecular switches. Presently, these simple molecular processors are far from any practical application. However, these encouraging results demonstrate already that chemical systems can process binary data with designed logic protocols. Further fundamental studies on the various facets of this emerging area will reveal if and how molecular switches can become the basic components of future logic devices. After all, chemical computers are available already. We all carry one in our head! And the molecules which can act as the molecular switches are fullerene derivatives, biological molecules, DNA base guanine etc.

Photonic Crystals and Photonic Integrated Circuits

Photonic crystals and photonic integrated circuits could pack in individual components a million times more densely than conventional ones. The tighter confinement and novel dispersion properties also open up many new applications, particularly for nonlinear (optical) devices and very low power devices in communication sector. The role of nanotechnology is fundamental to such exploitation, because quantum effects appear on small length and time-scales. Photonic nanocrystals are periodic dielectric or metallic structures having photonic bands in analogy to electronic bands of semiconductors. The presence of photonic band-gaps, where the propagation of photons of certain frequencies is prohibited, and the variety of photon dispersions give rise to novel and unusual optical phenomena. Examples of such photonic nano crystals include InGaAsP/InP 2D photonic crystals, 2D AlGaAs, silicon nitride/silicon-oxide etc.

Semiconductor lasers

Semiconductor lasers are said to be "the laser of the future". The reasons are: they are compact, they have the potential of mass production, they can be easily integrated, their properties are in rapid improvement, they are becoming more and more powerful and efficient and they have found a widespread use as pumps for solid–state lasers. The majority of semiconductor materials are based on a combination of elements in the third group of the periodic table (such as Al, Ga, In) and the fifth group (such as N, P, As, Sb) hence referred to as the III-V compounds. Examples include GaAs, AlGaAs, InGaAs and InGaAsP alloys. The laser emission wavelengths are normally within 630~1600 nm, but recently InGaN semiconductor lasers were found to generate 410 nm blue light at room temperature.

The semiconductor lasers that can generate blue-green light use materials which are the combination of elements of the second group (such as Cd and Zn) and the sixth group (S, Se). The principle of semiconductor laser is very different from CO2 and The semiconductor materials have valence band V and conduction band C, the energy level of conduction band is Eg (Eg>0) higher than that of valence band. To make things simple, we start our analysis supposing the temperature to be 0 K. It can be proved that the conclusions we draw under 0 K applies to normal temperatures. Semiconductor photon sources come in two major categories laser diodes and light-emitting diodes. Semiconductor lasers are the most basic of the existing laser types. In their simplest form they consist of a small rectangular slab of semiconductor material with two cleaved facets to act as mirrors. The other facets are destroyed in some way (etched, ground, sawn, ion implanted) in order to avoid spurious laser modes.

High frequency communication devices

Advanced information and communication networks are constantly evolving to keep up with the popularity of mobile phones, personal computers, and the Internet. High frequency devices are becoming essential for wireless communications with higher speed and higher capacity to provide greater mobility for users.

a) Monolithic microwave IC (MMIC):

Micro wave communication is a most popular and widely used means of communication especially in the case of cell phones. The very fact that the microwave also travels with almost the same velocity as that of light, made this momentum possible. Microwave can penetrate earths atmosphere without loss and can travel all the way to mars and even further. Normally used microwave frequency range is around 3-300 GHz. And common source used was silicon transistor of 25 GHz as the source. Much more high frequency and compact sources of GaAs (50 GHz) and InP (180 GHz) are replacing the conventional sources currently. Transistors and passive parts are integrated into the same GaAs substrate provides high functionality and high performance in extremely high frequency (EHF), plus miniaturization by function integration. Demand is increasing for MMIC’s in fields of satellite communications, high-speed wireless access, and intelligent transportation systems.

b) Low Noise HEMT (High Electron Mobility Transistor)

Used for BS/CS broadcast reception; meets requirements for lower noise characteristics in a higher frequency for interactive digital satellite broadcasting systems. Lead-less structure provides excellent high frequency characteristics and stable performance.

c) High Power FET (Field Effect Transistor)

Used for transmission of terrestrial microwave communications and satellite communications, plus communications between base stations for cell phones and wireless Internet access. Their high power, high efficiency, and low noise are ideal for applications in base stations for high-speed and high capacity digital information, an expanding market.

MEMS based worldwide Network/Communications Options

There are three major satellite networks based on MEMS. They are

1. RF-based Satellite Constellation: Probes directly and send discrete data packets to (Low earth orbit) LEO satellite(s) for collection.

2. Mobile Ad hoc Network: Data packets hop through mobile network to be distributed at exfiltration nodes.

3. Hybrid: Combination of the two depending upon probe location and conditions.

Spreading the energy of the communications signal over a wider range of frequencies can be accomplished in a number of different ways. Two of the methods are frequency hopping spread spectrum (FHSS) and direct sequence spread spectrum (DSSS). Both methods use a related but different approach to spread the signal. Ultra-wideband techniques spread the signal over very large frequency ranges. In each case, the key is to make certain that the transmitter and receiver can lock in quickly and synchronize the spreading and dispreading actions.

Accomplishments based on MEMS

Weather forecasting

Using one of the micro-weather stations, we can strip off the radio and can be wired in a laser pointer. This can go to a distant office laptop, where the software decodes flashing lights in the image, and can give the weather information 21 km away.

Large angle MEMS beam-steering

The laser motes above need to be aimed. A sub-millimeter mirror coupled to two motors on the same silicon chip. The motors can scan a reflected laser beam tens of degrees in either direction.

Silicon maple seeds

Using a honeycombed layer of silicon only 0.1 mm thick 3x10 mm winglet has been made. With a cubic millimeter of Silicon attached, these wings auto-rotate as they fall, just like a maple seed. The next generation will have solar cells built right in.

Smart dust virtual key board

Battlefield surveillance, treaty monitoring, transportation monitoring, scud hunting, etc. can be performed and be communicated.

Autonomous sensing and communication in a cubic millimeter

It is possible to glue a dust mote on to the fingernails. Accelerometers in the smart dust will sense the orientation and motion of each of the fingertips, and can talk to the computer in real time. Combined with MEMS the display, in entire computer I/O would be invisible to the people around us. Chatting can be done with wireless access and we need never be bored in a meeting again! It is a never ending list of applications such as the product quality monitoring, temperature & humidity monitoring of meat & dairy products, impact, vibration & temperature monitoring of consumer electronics etc. are of in credit to the smart dust. The Center for the Built Environment has fabulous plans for the office of the future in which environmental conditions are tailored to the desires of every individual. Maybe soon we'll all be wearing temperature, humidity, and environmental comfort sensors sewn into our clothes, continuously talking to our workspaces which will deliver conditions tailored to our needs.

Social welfare activities like developing interfaces for the handicapped or disabled with the potential benefits of outweighing the risks to personal privacy can be generated. A lot of people seem to be worried about environmental impact. Even in wildest imagination it doesn’t appears that we’ll be capable of making enough Smart Dust to bother anyone. If Intel stopped producing Pentia and produced only Smart Dust, and we spread them evenly around the country, we would get around one grain-of-sand sized mote per acre per year. If by ill chance we did inhale one, it would be just like inhaling a gnat. We would cough it up. Consider the scale - if we make a million dust motes, they have a total volume of one liter. Throwing a liter worth of batteries into the environment is certainly not going to help it, but in the big picture it probably doesn't make it very high on the list of bad things to do to the planet.

A smart dust can act as a distributed autonomous sensor network. Smart dust will facilitate innovative methods for micro fabrication technology and interact with the environment, providing more information from more places less intrusively. Smart dust requires evolutionary and revolutionary advances in miniaturization, integration and energy management. Potential uses include military applications in tracking enemy troop movements from above and detecting chemical warfare agents in the air. Monitoring weather conditions around the globe and detecting fires and earth quakes are among the nonmilitary uses. Stationary motes could be used to monitor the quality of products from factory to consumer.

Communication: Means and devices in nano regime

Nano/Micro Electro Mechanical Systems

Smart matter is another term for micro-electromechanical systems (MEMS), a technology

that combines computers with tiny mechanical devices such as sensors, valves, gears, mirrors, and actuators embedd d in semiconductor chips. Microelectronic integrated circuits can be thought of as the "brains" of a system and MEMS do this decision-making capability to allow microsystems to sense and control the environment. It will be the foundation technology of the next decade. Basically, a MEMS device contains microcircuitry on a tiny silicon chip into which some mechanical device such as a mirror or a sensor has been manufactured. Potentially, such chips can be built in large quantities at low cost, making them cost-effective for many uses. Presently available uses of MEMS are where one can include sensors that can be used for global tracking of the couriers or parcels. In flights the wing can be fabricated with sensors which can sense and react to the air flow by changing the wing surface resistance by creating indefinite number of tiny wing flaps. The optical lighting system can be made so effective so that the light signals over different paths can be switched on at 20 nano second switching speeds. In engines or in factories a sensor driven heating and cooling system is established that dramatically improve energy savings. And similarly building materials can incorporate sensors based on mems which can alter the flexibility properties of a material based on atmospheric stress sensing. MEMS devices are already used in such fields as the automotive industry, where they are incorporated into airbag and vehicle control; medicine, where they are used to control medication dosing and control medical devices such as pacemakers. They are used to make pressure, temperature, chemical and vibration sensors, light reflectors and switches as well as accelerometers for vehicle control.

The technology is also used to make ink jet print heads, micro actuators for read/write heads and all-optical switches that reflect light beams to the appropriate output port. MEMS combine many disciplines, including physics, bioinformatics, biochemistry, electrical engineering, optics and electronics. Typical MEMS devices combine sensing, processing or actuating functions to alter the way that the physical world is perceived and controlled. MEMS devices began to materialize as commercial products in the mid-1990s. Sometimes MEMS and nanotechnology are terms that are used interchangeably, because they both deal with microminiaturized objects. However, they are vastly different. MEMS deals with creating devices that are measured in micrometers, whereas nantotechnology deals with manipulating atoms at the nanometer level. MEMS produce environmental observing capabilities, Commensurate with advances in atmospheric models, Mitigate loss of life and property through improved planning / response; improve weather forecasts especially for high impact weather events. MEMS have a unique ability to collect information, process it, determine a course of action, and then act as a trigger by communicating through an electronic interface. These capabilities allow MEMS to provide the "nuts and bolts" of advanced applications known as "smart devices," such as collision avoidance systems and wireless handsets. MEMS devices do not work in isolation; they are embedded systems that make it possible for a component to perform higher level functions, such as controlling the fuel to air mixture in a car's engine.

In an optical switch, MEMS mirrors reflect the input signal to an output port without regard to line speed or protocol. This technology is expected to be the dominant method for building photonic switches which are essential part of the communication devices. In the future, nanotechnology will no doubt enable revolutionary sensors and communication devices although there are as of yet no commercial devices of this type based on true nanotechnology. However, because of the large potential markets, much effort is now being expended to create such devices.

Satellite communication

A satellite is a radio relay station in orbit above the earth that receives, amplifies and redirects analog and digital signals contained within a carrier frequency. They are of three types. Geostationary (GEO) satellites are in orbit 22282 miles above the earth and rotate with the earth, thus appearing stationary. The downlink from GEOs to earth can be localized into small regions or cover up as much as a third of the earth's surface. Low-earth orbit (LEO) satellites reside 1000 miles above the earth and revolve around the globe every couple of hours. They are in view for a few minutes, and multiple LEOs are required to keep continuous coverage. Medium-earth orbit (MEO) satellites are in the middle, taking about six hours to orbit the earth and can be viewed for a couple of hours.

The first communications satellite was launched in 1960 and it was an instrumented inflatable sphere which just reflected radio signals back to the earth.

Semiconductor quantum dots, which cover almost completely the entire spectral region from the ultraviolet to the far infrared, with a small number of substrate materials are suitable candidates in satellite communications. Further advantages of quantum dot lasers are small energy consumption through low threshold current densities, a high modulation range for high-speed applications as well as improved temperature stability. For example

InGaAs Quantum dot lasers are already commercialised in communication satellites. Ken Teo and his team at the University of Cambridge have come up with a much more efficient and compact way to send signals from satellites. They have managed to use an array of carbon nanotubes to create a device that replaces conventional heavy, bulky, high temperature, microwave amplifiers. The new electron source promises to revolutionize telecommunications and satellite communications in space.

Communication, especially to remote areas, is made possible with the use of satellite-based transmitters. There are typically 50 microwave amplifiers on board a satellite, each weighing about 1kg and measuring about 30 cm in length. Currently it costs about 10,000 pounds sterling to send a single kilogram of payload (data) into space. There is an advantage, both in terms of cost savings and extra payload that can be carried, if the weight and size of the microwave devices are reduced.

Nano Materials

nanotechnology in food

nanotechnology in cancer

nanotechnology

As cheap as the sweetener in your soda

A world leader in nanotechnology research, Prof. Gazit has been developing arrays of self-assembling peptides made from proteins for the past six years. His lab, in collaboration with a group led by Prof. Gil Rosenman of TAU's Faculty of Engineering, has been working on new applications for this basic science for the last two years.

Using a variety of peptides, which are as simple and inexpensive to produce as the artificial sweetener aspartame, the researchers create their "self-assembled nano-tubules" in a vacuum under high temperatures. These nano-tubules can withstand extreme heat and are resistant to water.
"We are not manufacturing the actual material but developing a basic-science technology that could lead to self-cleaning windows and more efficient energy storage devices in just a few years," says Adler-Abramovich. "As scientists, we focus on pure research. Thanks to Prof. Gazit's work on beta amyloid proteins, we were able to develop a technique that enables short peptides to 'self-assemble,' forming an entirely new kind of coating which is also a super-capacitor. "

As a capacitor with unusually high energy density, the nano-tech material could give existing electric batteries a boost - necessary to start an electric car, go up a hill, or pass other cars and trucks on the highway. One of the limitations of the electric car is thrust, and the team thinks their research could lead to a solution to this difficult problem.

"Our technology may lead to a storage material with a high density," says Adler-Abramovich. "This is important when you need to generate a lot of energy in a short period of time. It could also be incorporated into today's lithium batteries," she adds.

Are we invited to the nanotechnology party

Huge research funds are devoted to nanotechnology as it promises to transform many aspects of our lives. There are several phases to the development of the science.

The first stage is the creation of passive nanostructures - think "paint" or "additives". Next comes the creation of nanostructures that perform primitive functions - think "transistor". After that comes the creation of miniscule machines, preferably programmable, whose components are the primitives. These machines are called nanites.

The final phase is the creation of nanites that are capable of creating other nanites and then, when there are enough of them, acting collaboratively to achieve a common goal.

As computer scientists, we wish to play our part. Initially, this will be by offering services such as simulations and computer graphics to those involved in the first three phases. But we must prepare ourselves for the final phase, predicted to start around 2020. We want computer science to have matured so that we can cope.

Computer scientists are well placed to undertake the theoretical groundwork for this final phase because, ever since computers became distributed, we have been gaining expertise in the design and management of groups of physical entities working together. Furthermore, we have considerable experience with virtual entities working together, namely, software agents.

Some time ago, many researchers split off from the traditional AI approach and began to develop software agents. It was realised that in certain situations, we do not need monolithic programs to achieve something that passes for intelligent behaviour. The traditional way was to explicitly program intelligence into the software. With agents we do not necessarily have to do this. One approach is to program each agent to follow the same set of fairly simple rules, in priority order, and collectively they can achieve a goal. We say that intelligence has "emerged".

One example of this could be in programming robotic vehicles to pick up rocks lying in clusters on Mars. It is possible to program the vehicles to do this without even communicating with one another. It would be better, though, if on finding a cluster, a vehicle could inform others by leaving a trail.
The above example mimics the natural world where social animals work collaboratively. For example, consider the behaviour of a colony of ants. Ants leave a chemical trail for other ants to follow. The colony achieves a relatively complex goal even though an individual is following simple rules, and there is not even a leader.

There is in fact an algorithm called the ant colony optimisation algorithm as well as other algorithms modelled on collaborative animal behaviour. Collectively, these are known as swarming algorithms.

Computer scientists' expertise in networking and software agents is invaluable when it comes to programming and controlling armies of nanites.

Genetic algorithms have been in use for quite a while. They are used to improve the solution to a problem over successive generations. A key feature is that, every now and then, we perform a mutation so as not to get stuck in a rut. When armies of nanites become a reality, we will have to look at this problem in reverse and have to cope with nanites that have mutated.

Our study of software agents as well as swarming algorithms has wide-ranging applications outside nanotechnology. We do not have to wait for chemists and biologists to perfect the production of nanites, as nano-inspired computing is with us today.

Nanomaterials with a Bright Future

A new fabrication technique, known as soft interference lithography (SIL), makes it possible to inexpensively produce large sheets of gold films with virtually infinite arrays of perforations and microscale "patches" of nanoscale holes. A combination of interference lithography and soft lithography, SIL offers many significant advantages over existing techniques. It can be used to scale-up the nanomanufacturing process to produce plasmonic metamaterials and devices in large quantities. Devices such as films of nanoholes can also serve as templates to make their inverse structures, such as nanoparticles. (Legend: Si = silicon; Cr = chromium; PEEL = electron spectroscopy method called parallel electron energy loss spectroscopy.) Credit: Reprinted by permission from Macmillan Publishers Ltd: "Multiscale patterning of plasmonic metamaterials," Joel Henzie, Min Hyung Lee and Teri W. Odom, Nature Nanotechnology 2, 549 - 554 (2007)

An innovative and inexpensive way of making nanomaterials on a large scale has resulted in novel forms of advanced materials that pave the way for exceptional and unexpected optical properties. The new fabrication technique, known as soft lithography, or SIL, offers many significant advantages over existing techniques, including the ability to scale-up the manufacturing process to produce devices in large quantities.

Technology

The High Gravity Controlled Precipitation (HGCP) technology platform was developed based on fundamental mass transfer principles wherein micro mixing of the reaction phases is achieved in microseconds, with the reaction phases brought together under a high gravity environment. The High Gravity Controlled Precipitation (HGCP) is a platform technology through which a wide range of nano-sized materials can be developed.

Advantages of the High Gravity Controlled Precipitation (HGCP) technology platform are:

• Scalability: Cost effective scale up for large scale production of nanomaterials

• Control: Good control over quality, particle size and distribution, particle shape and morphology of the nanomaterial

• Versatility: Can be used for different nanomaterial synthesis

High Gravity Controlled Precipitation (HGCP)

India 'must regulate nanotechnology' urgently

Indian scientists have called for the development of regulations on the safe use of nanotechnology in healthcare and the environment.

The absence of regulations for nanotechnology in India and worldwide is a serious problem, said Prasenjit Sen, from Delhi's Jawaharlal Nehru University, at a meeting this week (8 October) in Delhi, India, to discuss the key problems that India faces in its quest to develop the emerging technology.
Several Indian institutes and firms are already working on nanotechnology products for drug delivery, water filters, arsenic removal, reducing water and air pollution, antimicrobial coatings and river cleaning projects, Sen said, and the country must develop guidelines on nanoparticle toxicity and biosafety.

Scientists from the Energy Resources Institute in Delhi launched a study this year to investigate the opportunities and risks associated with the technology.

The meeting also heard that India lacks a sizeable pool of young researchers trained in nanoscience and nanotechnology, and that the country has relatively few patents and publications in peer-reviewed journals.

Earlier this year, India launched a programme to promote nanoscience and nanotechnology with a budget of 10 trillion Indian rupees (US $ 255 million). But although several public and private research institutes are working on DNA chips, carbon nanotubes, nanoparticles such as iron oxide and silver oxide, and products such as paints and polymers, experts noted a general lack of enthusiasm from Indian industry.

There has been no effort to link the technology's potential with development in agriculture and addressing the needs of people in rural areas, who form the backbone of India's economy, said Anil Rajvanshi, director of the Nimbkar Agriculture Research Institute in the state of Maharashtra in western India.

For example, nanomaterials could help improve solar cells and biogas reactors, said Rajvanshi. But so far the government has shown no interest in funding such projects.

Value and Scope of Nanotechnology in India

Nanotechnology is derived from the combination of two words Nano and Technology. Nano means very small or "miniature". So, Nanotechnology is the technology in miniature form. It is the combination of Bio-technology, Chemistry, Physics and Bio-informatics, etc.

Nanotechnology originated in India around 16 years back. It is in its early development phase and therefore the industry keeps a keen watch over the students who pursue M. Tech. innanotechnology. There are several career opportunities for such students in domestic as well as international markets.

This new sphere of scientific innovation has a broader scope. Several Indian institutes have introduced degree courses in Nanotechnology at both the UG and PG levels. The areas covered in the Nanotech are Food and Beverage, Bio-Technology, Forensic Sciences, Genetics, Space Research, Environment industry, Medicine, Agriculture and Teaching.

The three chief divisions of Nanotech are Nanoelectronics, Nanomaterials, and Nano-Biotechnology. The implications of Nanotechnology in India can be found in the field of telecommunications, computing, aerospace, solar energy, and environment. However, Nanotech's major contribution can be seen in the computing, communication and, medical field.

Nanomedicine is the most important field of Nanotechnology. The nano level gadgets and materials are used for diagnosing and treatment of diseases. Nano-Pharmacology has generated a specific category of smart drugs that affect negligible side effects. The use of Nanotech has also helped in the detection of narcotics and fingerprints of the suspected criminals.

The Council of Scientific and Industrial Research, also known as CSIR has set up 38 laboratories in India dedicated to research in Nanotechnology. This technology will be used in diagnostic kits, improved water filters and sensors and drug delivery. The research is being conducted on using it to reduce pollution emitted by the vehicles.

Looking at the progressive prospects of Nanotechnology in India, Nanobiosym Inc., A US-based leading nanotechnology firm is planning to set up India's first integrated nanotechnology and biomedicine technology park in Himachal Pradesh. Nanotechnology has certainly acquired an essential position in the Indian Economy and Scientific Research Department and it is expected to reach the pinnacle of Development thereby making India a role model for the countries of the world.

Multi-purpose nanotechnology innovation parks for India

US-based Nanotechnology firm Nanobiosym is planning to set up multi-purpose nanotechnology innovation parks, the first of its kind in India.

Himachal Pradesh and Gujarat have already signed MOUs with the globally recognised firm to establish the Nanobiosym Tech Park in India.

"Nanobiosym is already at work forming strategic alliances and innovative public-private partnerships with governments and NGOs and the private sector to help make its flagship Gene-RADAR technology available and affordable to people in developing countries sooner rather than later," Nanobiosym Chairman and CEO Anita Goel told PTI from Boston.

"Our motto is, with one stroke of the tiny nanotech product platform (Gene-RADAR), to alter the landscape of several multi-billion dollar global industries such as water testing, food and beverage safety testing, biodefence and biometrics, in addition to personalised medicine and point of care diagnostics, "

Nanotechnology in the Food Industry

The impact of nanotechnology in the food industry has become more apparent over the last few years with the organization of various conferences dedicated to the topic, initiation of consortia for better and safe food, along with increased coverage in the media. Several companies which were hesitant about revealing their research programmes in nanofood, have now gone public announcing plans to improve existing products and develop new ones to maintain market dominance. The types of application include: smart packaging, on demand preservatives, and interactive foods. Building on the concept of “on-demand” food, the idea of interactive food is to allow consumers to modify food depending on their own nutritional needs or tastes. The concept is that thousands of nanocapsules containing flavour or colour enhancers, or added nutritional elements (such as vitamins), would remain dormant in the food and only be released when triggered by the consumer.24 Most of the food giants including Nestle, Kraft, Heinz, and Unilever support specific research programmes to capture a share of the nanofood market in the next decade.

The definition of nanofood is that nanotechnology techniques or tools are used during cultivation, production, processing, or packaging of the food. It does not mean atomically modified food or food produced by nanomachines. Although there are ambitious thoughts of creating molecular food using nanomachines, this is unrealistic in the foreseeable future.

Instead nanotechnologists are more optimistic about the potential to change the existing system of food processing and to ensure the safety of food products, creating a healthy food culture. They are also hopeful of enhancing the nutritional quality of food through selected additives and improvements to the way the body digests and absorbs food. Although some of these goals are further away, the food packaging industry already incorporates nanotechnology in products.