Let's Talk

The Fixing Carbon Scrubber

2009-11-07T01:02:00.001+08:00

Are you one of the person who is in race to save the earth? want to help to reduce Global Warming ? then this is something you should know.
Carbon Scrubber -
a prototype for fixing carbon dioxide from atmosphere around you.
carbon scrubber is a device that is basically consist of honeycomb fillters,soduim hydroxide and a fan to extract air from atmosphere. exracted air is sprayed with NaOH solution and filtered air is expelled out. When this devide was tested it extract 430 kg air and filtered out 25kg carbon dioxide from it. isnt it great!!!!
click for video here to see how this scrubber works exactly.though this scrubber is a great discovery but to bring it into commercial use it has still few hurdels among which cost is the important factor.
i request people to use various ways to save the environement around you else the deadline for earth to finish is not so far.

Reduce Global Warming. Save Earth. Save yourself.

If anyone reads this blog please comment and discuss how we can help to reduce global warming.

with love and peace
Abhinav Harlalka

DNA Stretching

2009-10-21T00:39:00.000+08:00

i was just surfing through some recent science and innovation updates and i found one of the most research project which is being given emphasis in many labs across world that is " Stretching of DNA". i am not a biology person so couldn't understand it much but would like to.
According to recent results

Researchers in Europe have literally unravelled a mystery that has been puzzling scientists for years: what happens to a molecule of DNA when it is stretched to its breaking point. The question is important because DNA is subjected to a range of mechanical manipulations within the cell: it can be folded, unfolded, coiled and uncoiled, unzipped and zipped up again. A detailed understanding of the elastic properties of DNA can give scientists key insights into interactions of DNA and the proteins that carry out these manipulations.

Almost two decades ago it was shown that when a molecule of double-stranded DNA is pulled from either end, it undergoes a peculiar transition. Initially the molecule resists stretching. Then, at a force of 65 piconewtons, the polymer suddenly surrenders and stretches to 1.7 times its original length with little additional force. It then becomes resistant to stretching once more.

research on strethcing of DNA from my point of view is imp may be for the study of enzymes interacting with Dna or to obtain some kind of genetic information..from 1997 research is going on this project and still scientist are working on.
here are some links for more information

http://www.rsc.org/chemistryworld/News/2009/October/19100902.asp

http://www.sciencedaily.com/releases/2006/12/061206091654.htm#

http://www.lbl.gov/Science-Articles/Archive/PBD-stretched-DNA.html

if anyone of you could understand this aspect mcuh better pls feel free to comment.
With love & peace
Abhinav

2009-10-19T03:04:00.000+08:00

Controlling carbon nanotubes

Nanoscopic tubes made of a lattice of carbon just a single atom deep hold promise for delivering medicines directly to a tumor, sensors so keen they detect the arrival or departure of a single electron, a replacement for costly platinum in fuel cells or as energy-saving transistors and wires.

Single-walled carbon nanotubes, made of a cheap and abundant material, have so much potential because their function changes when their atomic-level structure, referred to as chirality, changes. But for all their promise, building tubes with the right structure has proven a challenge.
A pair of Case Western Reserve University researchers mixed metals commonly used to grow nanotubes and found that the composition of the catalyst can control the chirality. In a letter published in Nature Materials, R. Mohan Sankaran, an assistant professor of chemical engineering at the Case School of Engineering, and Wei-Hung Chiang, who received his doctorate degree in chemical engineering in May, describe their findings.

"We have established a link between the structure of a catalyst and the chirality of carbon nanotubes," Sankaran said. "Change the catalyst structure by varying its composition, and you can begin to control the chirality of the nanotubes and their electrical and optical properties."

The chirality of a single-walled carbon nanotube describes how a lattice of carbon atoms is rolled into a tube. The rolling can occur at different angles, producing different structures that exhibit very different properties. Nanotubes are normally grown in bulk mixtures. When using a nickel catalyst, typically one-hird of those grown are metallic and could be used like metal wires to conduct electricity. About two-thirds are semiconducting nanotubes, which could be used as transistors, Chiang explained. But, separating them according to properties, "is costly and can damage the nanotubes." Chiang and Sankaran found that a mixed iron and nickel catalyst could change the outcome. Of the compositions tested, a catalyst of 27 percent nickel and 73 percent iron produced the most dramatic result: the vast majority of the nanotubes were semiconducting. They are now working on assessing the purity and integrating the nanotubes into thin film transistors. The authors say their findings open the door to experimenting with other elements as catalysts and different combinations, which may produce near-pure nanotubes with desired properties.

Original publication: "Linking catalyst composition to chirality distributions of as-grown single-walled carbon nanotubes by tuning NIxFe1-x nanoparticles."; Nature Material2009.

Solar cell : highest efficiency

2009-09-24T02:00:00.000+08:00

Aussies help set new solar power world record

Australian solar cell researchers have played a key role in achieving the highest efficiency for solar power ever recorded, setting a new world record of 43 per cent of sunlight converted into electricity.

The team of Australian scientists, from the University of New South Wales, combined with two US groups to demonstrate a multi-cell combination which has set the new benchmark for converting sunlight into electricity by any possible approach.
"Because sunlight is made up of many colours of different energy, ranging from the high energy ultraviolet to the low energy infrared, a combination of solar cells of different materials can convert sunlight more efficiently than any single cell," said Martin Green, research director of the UNSW ARC Photovoltaics Centre of Excellence.

Green led the team that developed a silicon cell optimised to capture light at the red and near-infrared end of the light spectrum. That cell was able to convert up to 46 per cent of light in that colour range into electricity.
When combined with four other cells, each optimised for different parts of the solar spectrum, the five-cell combination converted 43 per cent of the sunlight hitting it into electricity, improving on the previous world record by 0.3 per cent.

Stuart Wenham, Director of the ARC Centre, said the new record was not directly comparable to the 25 per cent efficiency world record for an individual solar cell set by UNSW last year; however, it was an important pointer for the future potential of solar photovoltaic power.

The latest research will be published in the journal Progress in Photovoltaics in September

CNT growth without metal catalyst

2009-09-19T02:57:00.000+08:00

Researchers make carbon nanotubes without metal catalyst

Carbon nanotubes - tiny, rolled-up tubes of graphite - promise to add speed to electronic circuits and strength to materials like carbon composites, used in airplanes and racecars. A major problem, however, is that the metals used to grow nanotubes react unfavorably with materials found in circuits and composites. But now, researchers at MIT have for the first time shown that nanotubes can grow without a metal catalyst. The researchers demonstrate that zirconium oxide, the same compound found in cubic zirconia "fake diamonds," can also grow nanotubes, but without the unwanted side effects of metal.

The implications of ditching metals in the production of carbon nanotubes are great. Historically, nanotubes have been grown with elements such as iron, gold and cobalt. But these can be toxic and cause problems in clean room environments. Moreover, the use of metals in nanotube synthesis makes it difficult to view the formation process using infrared spectroscopy, a challenge that has kept researchers in the dark about some of the aspects of nanotube growth.

"I think this fundamentally changes the discussion about how we understand carbon nanotubes synthesis," says Brian Wardle, professor of aeronautics and astronautics who led the study, published Aug. 10 in the online version of the Journal of the American Chemical Society.

Wardle adds that some researchers might find the result controversial since no one has ever proven that anything other than a metal can grow a nanotube. "People report new metals [as catalysts] every so often," he says. "But now we have a whole new class of catalyst and new mechanism to understand and debate."

The conventional model for nanotube growth goes like this: A substrate is sprinkled with nanoparticle seeds made of a certain metal, of the same diameter of the desired nanotubes. The substrate and nanoparticles are heated to 600 to 900 degrees Celsius, and then a carbon-containing gas such as methane or alcohol is added. At the high temperatures, molecules break apart and reassemble. Some of these carbon-containing molecules find their way to the surface of a nanoparticle where they dissolve and then precipitate out, in nanotube form.
The researchers found that if they just used zirconium oxide nanoparticles on the substrate, they could coax carbon into nanotubes as well. Importantly, the mechanism for growth seems to be completely different from that of metal nanoparticle-grown tubes. Instead of dissolving into the nanoparticle and precipating out, zirconia-grown nanotubes appear to assemble directly on the surface.
In collaboration with Professor Stephan Hofmann at the University of Cambridge in England, the MIT researchers took images of the oxide-based nanotubes using X-ray photoelectron spectroscopy during growth. This allowed them to see that when nanotubes formed, zirconium oxide persisted, and didn't form into a metal, bolstering their conclusions.

One of the most exciting implications of the finding is that it means that carbon fiber and composites, used to make different types of crafts, could be strengthened by nanotubes. "Composites are durable, but fail under certain loading conditions, like when plywood flakes and splinters apart," says Stephen Steiner, an MIT graduate student and the study's first author. "But what if you could reinforce composites at the microlevel with nanotubes the way that rebar reinforces concrete in a building or a bridge? That's what we're trying to do to improve the mechanical properties and resistance to fracturing of carbon composites."

Steiner says the reason that planes like Airbus' A380 and Boeing's new 787 are made of only 40 percent composites and not 90 percent is because composites aren't strong enough for all parts of the craft. But if they were bolstered by nanotubes, then the planes could be made of more composites, which would make them lighter, and less expensive to fly because they wouldn't need as much fuel.

The findings are already impressing researchers in industry. "This innovation has far-reaching implications for commercial productions of carbon nanotubes," says David Lashmore, CTO of Nanocomp Technologies Inc., a company in Concord, N.H., that was not involved in the research. "It for the first time allows the use of a ceramic catalyst instead of a magnetic transition metal, some of which are carcinogenic."

Wardle suspects that more oxide-based catalysts will be found in the coming years. He and his team will focus on trying to understand the fundamental mechanisms of this type of nanotube growth and help to contribute more types of catalysts to the nanotube-growing arsenal. While the researchers don't have a timeline, they suspect that it would be easy to commercialize the process as it's simple, adaptable and, in many ways, more flexible than growth with metal catalysts.

This work was supported by Airbus S.A.S., Boeing, Embraer, Lockheed Martin, Saab AB, Spirit AeroSystems, Textron Inc., Composite Systems Technology, and TohoTenax through MIT's Nano-Engineered Composite aerospace Structures (NECST) Consortium.

Nanocrystal real time growth

2009-09-19T02:35:00.000+08:00

Real time nanocrystal growth in solution for the first time

The veil is being lifted from the once unseen world of molecular activity. Not so long ago only the final products were visible and scientists were forced to gauge the processes behind those products by ensemble averages of many molecules. The limitations of that approach have become clear with the advent of technologies that allow for the observation and manipulation of single molecules. A prime example is the recent first ever direct observations in real-time of the growth of single nanocrystals in solution, which revealed that much of what we thought we knew is wrong.

Interim Berkeley Lab Director Paul Alivisatos and Ulrich Dahmen, director of Berkeley Lab’s National Center for Electron Microscopy (NCEM), led a team of experts in nanocrystal growth and electron microscopy who combined their skills to observe the dynamic growth of colloidal platinum nanocrystals in solution with subnanometer resolution. Their results showed that while some crystals in solution grow steadily in size via classical nucleation and aggregation - meaning molecules collide and join together - others grow in fits and spurts, driven by “coalescence events,” in which small crystals randomly collide and fuse together into larger crystals. Despite their distinctly different growth trajectories, these two processes ultimately yield a nearly monodisperse distribution of nanocrystals, meaning the crystals are all approximately the same size and shape.

“Coalescence events have been previously observed in flask synthesis of colloidal nanocrystals and has been considered detrimental for achieving monodisperse colloidal nanocrystals,” says Haimei Zheng, a chemist in Alivisatos’ research group, who was the lead author on a paper that reported these results in the journal Science. “In our study, we found that coalescence events are frequently involved in the early stage of nanocrystal growth and yet monodisperse nanocrystals are still formed.”

Says Alivisatos, a chemist who holds joint appointments with Berkeley Lab and the University of California at Berkeley where he is the Larry and Diane Bock professor of Nanotechnology, “This direct observation of nanocrystal growth trajectories revealed a set of pathways more complex than those previously envisioned and enables us to re-think the nanocrystal growth mechanism with an eye towards more controlled synthesis.”
These TEM images show comparisons between the nanocrystal growth trajectories of monomer attachments (a) and coalescence events (b). The Science paper was titled: “Observation of Single Colloidal Platinum Nanocrystal Growth Trajectories.” Co-authoring this paper with Zheng, Alivisatos and Dahmen were Rachel Smith, Young-wook Jun and Christian Kisielowski.
Nanocrystals are projected to play important roles in a wide-ranging number of technologies including solar and fuel cell, catalysis, electronics and photonics, medicine, and imaging and sensing. The key to success will be the ability to synthesis nanocrystals with desired physical properties. This will require a much better understanding of colloidal nanocrystal growth mechanisms. While the past two decades have seen tremendous advances in the synthesis of semiconductor, metal and dielectric nanocrystals, these advances have generally been realized through trial and error chemistry. A much more directed and controlled approach to nanocrystal synthesis is needed.

A new technique known as “liquid cell in situ transmission electron microscopy,” in which the powerful resolution capabilities of a transmission electron microscope (TEM) are brought to bear on a liquid cell that allows liquids to be observed inside a vacuum, enables the visualization of single nanoparticles in solution. The Berkeley researchers deployed this technique on NCEM’s JEOL 3010 In-Situ microscope. Utilizing an electron beam operating at 300 kilovolts of energy, the JEOL 3010 provides outstanding specimen penetration and spatial resolution of about 8 angstroms through the thick liquid cell sample.

“The JEOL 3010 In-Situ Microscope is our best machine for imaging dynamic events, and at 300kV the electron beam has enough penetrating power to maintain high resolution, even when looking through a liquid confined between two thin solid windows,” says NCEM director Dahmen. “Our resolution is significantly higher than any previous studies of this nature, which made it possible for us to measure the movement and growth of individual colloidal particles only a few nanometers in size.”

Haimei Zheng is a chemist in the research group of Paul Alivisatos who was the lead author on a Science paper that reports the first ever direct observations in real-time of the growth of single nanocrystals in solution. (Photo by Majed Abolfazli)

Zheng, Dahmen, Alivisatos and their colleagues used the JEOL 3010 and liquid cells microfabricated from a pair of 100-micron-thick silicon wafers with 20 nanometer thick silicon nitride membrane windows to image the growth trajectories of platinum nanocrystals in solution. Platinum nanocrystals are an ideal system for such studies because their high electron contrast allows liquid-cell TEM imaging of individual particles. The JEOL 3010’s electron beam was used to both trigger nucleation and drive crystal growth through reduction of the platinum cations.

“Video-rate acquisition allowed us to track nanocrystal growth trajectories from frame-to-frame,” says Zheng. “This allowed us to observe that each nanocrystal can either grow steadily through the addition of monomers from solution or by merging with another nanocrystal in random coalescence events.”

Zheng says it has been assumed that coalescence events would result in some crystals being much larger than others, a bad thing in that the physical properties of nanocrystals are so dependent upon size and shape that for many applications it is critical that monodispersed nanocrystals be produced during synthesis. Consequently, strategies such as the use of surfactants to coat nanocrystal surfaces have been adopted to avoid coalescence events.

“Our observations provide invaluable direct information on how nanocrystals grow and indicate how we might directly control nanocrystal synthesis for tailored properties,” says Zheng. “Also, our in situ liquid cell TEM technique can be applied to other areas of research such as soft matter imaging and nanoparticle catalysis, and offers great potential for addressing many fundamental issues in materials science, chemistry and other fields of science.”Says Dahmen, “From a microscopist’s point of view, the ability to observe nanoparticles in liquid solution opens new opportunities in an area that has traditionally been off-limits because electron microscopes require vacuum conditions. We can now see directly what before could only be surmised from the statistical behavior of the ensemble. It’s like understanding traffic by watching individual cars instead of listening to the traffic report.”

NCEM is a U.S. Department of Energy national user facility that is hosted at Berkeley Lab. Established in 1983, it stands today as one of the world’s foremost centers for electron microscopy and microcharacterization.
Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research for DOE’s Office of Science and is managed by the University of California.

Additional Information

For more information about the research of Paul Alivisatos visit the Website at http://www.cchem.berkeley.edu/pagrp/
For more information on the National Center for Electron Microscopy visit the Website at http://ncem.lbl.gov

Nano Bio updates

2009-09-19T02:17:00.000+08:00

Nanoelectronic transistor combined with biological machine could lead to better electronics

LIVERMORE, Calif. -- If manmade devices could be combined with biological machines, laptops and other electronic devices could get a boost in operating efficiency.

Lawrence Livermore National Laboratory researchers have devised a versatile hybrid platform that uses lipid-coated nanowires to build prototype bionanoelectronic devices.

Mingling biological components in electronic circuits could enhance biosensing and diagnostic tools, advance neural prosthetics such as cochlear implants, and could even increase the efficiency of future computers.
While modern communication devices rely on electric fields and currents to carry the flow of information, biological systems are much more complex. They use an arsenal of membrane receptors, channels and pumps to control signal transduction that is unmatched by even the most powerful computers. For example, conversion of sound waves into nerve impulses is a very complicated process, yet the human ear has no trouble performing it.
“Electronic circuits that use these complex biological components could become much more efficient,” said Aleksandr Noy, the LLNL lead scientist on the project.
While earlier research has attempted to integrate biological systems with microelectronics, none have gotten to the point of seamless material-level incorporation.

“But with the creation of even smaller nanomaterials that are comparable to the size of biological molecules, we can integrate the systems at an even more localized level,” Noy said.
To create the bionanoelectronic platform the LLNL team turned to lipid membranes, which are ubiquitous in biological cells. These membranes form a stable, self-healing,and virtually impenetrable barrier to ions and small molecules.

“That's not to mention that these lipid membranes also can house an unlimited number of protein machines that perform a large number of critical recognition, transport and signal transduction functions in the cell,” said Nipun Misra, a UC Berkeley graduate student and a co-author on the paper.

Julio Martinez, a UC Davis graduate student and another co-author added: “Besides some preliminary work, using lipid membranes in nanoelectronic devices remains virtually untapped.”
The researchers incorporated lipid bilayer membranes into silicon nanowire transistors by covering the nanowire with a continuous lipid bilayer shell that forms a barrier between the nanowire surface and solution species.
“This 'shielded wire' configuration allows us to use membrane pores as the only pathway for the ions to reach the nanowire,” Noy said. “This is how we can use the nanowire device to monitor specific transport and also to control the membrane protein.”
The team showed that by changing the gate voltage of the device, they can open and close the membrane pore electronically.

The research appears Aug. 10 in the online version of the Proceedings of the National Academy of Sciences.

Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.

Carbon Nanotube- treatment for cancer

2009-09-15T23:16:00.000+08:00

Golden nanotubes show super contrast

Researchers in Arkansas in the US have developed new nanomaterials – dubbed golden nanotubes – for use as super contrast agents for highly sensitive imaging of tumours and cancer cells. When intravenously injected with the nanotubes, mice with tumours in their lymph nodes show photoacoustic and photothermal signals that are 100 times stronger than those observed for ordinary carbon nanotubes. The nanomaterial, which can also be used to carry therapeutic agents thanks to its hollow core, could be used as a more efficient and less toxic alternative to other nanoparticles and fluorescent labels for non-invasive tumour imaging.

Most conventional optical imaging techniques are not suitable for imaging through thick living tissue because light is strongly scattered by biological matter. This leads to poor spatial resolution and features such as tumours are difficult to make out.

Photoacoustic and photothermal imaging overcomes this problem by measuring the ultrasound and heat produced by photons that are fired into a sample. The technique works because the sample heats up when it absorbs photons, causing it to expand. Pressure waves propagate out from the expanding structures and these can then be detected by an ultrasound transducer. The heat can also be detected by a photodetector.

Although it is efficient, the technique still requires contrast agents because diseases, such as tumours and cancer cells, do not show natural photoacoustic and photothermal contrast. Carbon nanotubes are promising candidates as contrast agents because they offer high resolution and allow deep tissue imaging. However, they do not absorb light very well in the near-infrared, a range important for biological imaging.

Gold layer around CNTs

Now, Jin-Woo Kim of the University of Arkansas and Vladimir Zharov of the University of Arkansas for Medical Sciences have overcome this problem by depositing a thin layer of gold around carbon nanotubes. The gold layer enhances absorption of near-infrared light.

"Our golden nanotubes absorb near-infrared radiation at least two orders of magnitude more effectively than traditional nanotubes," explained Kim. "Simply speaking, 100 times more ordinary carbon nanotubes are needed to have the same photoacoustic and photothermal response as golden nanotubes." Fewer golden tubes are thus required, and less is always better when injecting nanoparticles into the body, he added.

The hollow core may also be used to potentially carry therapeutic payloads, such as drugs.

"The unique properties of golden nanotubes make them an effective alternative to existing nanoparticles and fluorescent labels for non-invasive targeting of molecular structures in vivo," Zharov told nanotechweb.org. "They may be used for a variety of biomedical applications, including highly target-specific lymphatic diagnosis and therapy, as well as to treat tumours and infections."

The researchers will now continue exploring the optical properties of these nanoparticles and use double- and multi-walled carbon nanotubes as the core. They will also try adding different biomarkers to the tubes to target different types of cancer cell and investigate the in vivo toxicity of the materials in animals.

The work was reported in Nature Nanotechnology

Nanotechnology- Clean Water

2009-09-11T23:03:00.000+08:00

Nanotechnology for clean water: Facts and figures

Nanotechnology could help give millions clean drinking water. David J. Grimshaw outlines the potential, the progress and some of the risks.

Technology has long been important in providing clean drinking water and irrigation for food crops. Indeed, people have had water technology for thousands of years — the Romans were using aqueducts as conduits for drinking wateraround 300BC. But making modern technology accessible and affordable to the global poor is a daunting task. Can nanotechnology perform better than previous technologies?

Water is a scarce resource, and for many countries — particularly those in the Middle East — supplies already fall short of demand. With the pressures of climate change and population growth, water will become even scarcer, especially in developing regions. Moreover, in these regions, what water is available is often unsafe to drink

884 million people lack access to safe water supplies — approximately one in eight people

6 kilometres is the average distance African and Asian women walk to fetch water

3.6 million people die each year from water-related diseases

98 per cent of water-related deaths occur in the developing world

84 per cent of water-related deaths are in children ages 0–14

43 per cent of water-related deaths are due to diarrhoea

65 million People are at risk of arsenic poisoning in the Bangladesh, India and Nepal area

The quest to ensure that all people have access to clean drinking water is now enshrined in the UN's Millennium Development Goals, which aim to halve the proportion of people without sustainable access to safe drinking water by 2015. According to the World Water Assessment Programme, that will mean improving water supplies for 1.5 billion people.

But how to achieve this? Economics or technology have often driven approaches to providing water for poor communities. The economics route might typically centre on the importance of regulations, institutions and open markets. The technology approach might focus on designing a water pump, filter systems or novel applications, for example, of nanotechnology.

Nanotechnology's potential

Unlike other technologies, which have often sprung directly from a particular scientific discipline, nanotechnology spans a wide spectrum of science. Essentially, it is defined by the scale it operates at. Nanoscience and nanotechnology involve studying and working with matter on an ultrasmall scale. One nanometre is one-millionth of a millimetre and a single human hair is around 80,000 nanometres in width. This kind of scale is difficult for us to visualise but if the distance between the Sun and the Earth were one metre then a nanometre would be the size of a football pitch.

The nanoscale deals with the smallest parts of matter that we can manipulate. Operating at the nanoscale makes assembling atoms and molecules to exact specifications easier. Rather like building a model from Lego bricks, we might envisage creating new materials or modifying existing ones. In applications like water filtration this means materials can be tailored, or tuned, to filter out heavy metals and biological toxins.

Materials at the nanoscale often have different optical or electrical properties from the same material at the micro or macroscale. For example, nano titanium oxide is a more effective catalyst than microscale titanium oxide. And it can be used in water treatment to degrade organic pollutants. But in other cases, manufactured nanoparticles' small size may make the material more toxic than normal.

Nanotechnology can solve the technical challenge of removing salt from water

UCLA Engineering

The principal way nanotechnologies might help alleviate water problems is by solving the technical challenges that removing water contaminants including bacteria, viruses, arsenic, mercury, pesticides and salt pose.

Many researchers and engineers claim that nanotechnologies offer more affordable, effective, efficient and durable ways of achieving this — specifically because using nanoparticles for water treatment will allow manufacturing that is less polluting than traditional methods and requires less labour, capital, land and energy.

New technologies in the past have made similar claims. Yet if we could develop new business models that let us use nanotechnologies sustainably to solve real problems, identified in participation with local communities, we might have cause for optimism.

The story so far

A range of water treatment devices that incorporate nanotechnology are already on the market, with others either close to market launch or in the process of being developed.

Nanofiltration membranes are already widely applied to remove dissolved salts and micro-pollutants, soften water and treat wastewater. The membranes act as a physical barrier, capturing particles and microorganisms bigger than their pores, and selectively rejecting substances. Nanotechnology is expected to further improve membrane technology and also drive down the prohibitively high costs of desalination — getting fresh water from salty water.

Researchers are developing new classes of nanoporous materials that are more effective than conventional filters. For example, a study in South Africa has shown than nanofiltration membranes can produce safe drinking water from brackish groundwater. And a team of Indian and US scientists have developed carbon nanotube filters that remove bacteria and viruses more effectively than conventional membrane filters.

Naturally occurring attapulgite clays and zeolites are also used in nanofilters. These are locally available in many places around the world and have innate nanometer-size pores. A study using attapulgite clay membranes to filter wastewater from a milk factory in Algeria has shown they can economically and effectively reduce whey and other organic matter in wastewater, making it safe to drink.

Zeolites can also be fabricated. They can be used to separate harmful organics from water and to remove heavy metal ions. Researchers at Australia's Commonwealth Scientific and Research Organization have created a low-cost synthetic clay, hydrotalcite, that attracts arsenic, removing it from water. They have suggested a novel packaging for this product for low-income communities — a 'teabag' that can be dipped into household water supplies for about 15 minutes before drinking. And selling the used teabags back to the authorities might increase recycling and help with waste disposal of concentrated arsenic.

Nano catalysts, magnets and detectors

Nanocatalysts and magnetic nanoparticles are other examples of how nanotechnology could make heavily polluted water fit for drinking, sanitation and irrigation. Nanocatalysts owe their better catalytic properties to their nanosize or to being modified at the nanoscale. They can chemically degrade pollutants instead of simply moving them somewhere else, including pollutants for which existing technologies are inefficient or prohibitively expensive. Researchers at the Indian Institute of Science, in Bangalore, have used nano titanium dioxide for this very purpose (see 'Nanoscale water treatment needs innovative engineering').

Magnetic nanoparticles have large surface areas relative to their volume and can easily bind with chemicals. In water treatment applications, they can be used to bind with contaminants — such as arsenic or oil — and then be removed using a magnet. Several companies are commercialising such technologies and researchers are frequently publishing new discoveries in this area.

Nanorust and arsenic

CBEN/Rice University

For example, scientists at Rice University in the United States are using magnetic "nanorust" to remove arsenic from drinking water. Nanorust's large surface area means it can capture one hundred times more arsenic than larger counterparts. The team projects that 200–500 milligrams of nanorust could treat a litre of water. And it is developing a way of creating nanorust from inexpensive household items. This could significantly reduce production costs, making it a viable product for communities throughout the developing world.

As well as treating water, nanotechnology can also detect water-borne contaminants. Researchers are developing new sensor technologies that combine micro and nanofabrication to create small, portable and highly accurate sensors that can detect single cells of chemical and biochemical substances in water. Several research consortia are field testing such devices and some expect to commercialise these soon. For example, a team at Pennsylvania State University in the United States has developed a way of detecting arsenic in water by using nanowires on a silicon chip.

Nano research in the developing world

Research spending on nanotechnology in developed regions like Europe and the United States are very high as governments continue to prioritise technologies they think will underpin economic growth. And some intermediate countries, like China, are also investing heavily .

Research spending on nanotechnology

South Africa has developed important capabilities in nanotechnology through its National Nanotechnology Strategy, launched in 2006. It has, for example, set up innovation centres for nanoscience in two of the country's science councils. One of these includes a focus on nanoscience for water. The thrust of research here has very much been on solving local problems. The University of Stellenbosch, for example, is researching nanomembranes for water filtration.

India too has invested heavily in nanotechnology — although figures are difficult to verify, partly because investment is often a partnership between government and the private sector.

And other developing countries are increasingly seeing a need to support nanoscience, including research into how nanotechnology can help deliver clean water. Brazil, Cuba, Saudi Arabia and Sri Lanka all host nanoscience centres working on this issue. And the number of patents on nano-based inventions filed by developing country researchers is increasing rapidly.

Developments for the developing world

Some interesting products are now emerging from developing countries, and other products are being developed elsewhere that are highly relevant to the needs of the South.

Product How it works Importance Developer

Nanosponge for rainwater harvesting A combination of polymers and glass nanoparticles that can be printed onto surfaces like fabrics to soak up water Rainwater harvesting is increasingly important to countries like China, Nepal and Thailand. The nanosponge is much more efficient than traditional mist-catching nets Massachusetts Institute of Technology, United States

Nanorust to remove arsenic Magnetic nanoparticles of iron oxide suspended in water bind arsenic, which is then removed with a magnet India, Bangladesh and other developing countries suffer thousands of cases of arsenic poisoning each year, linked to poisoned wells Rice University, United States

Desalination membrane A combination of polymers and nanoparticles that draws in water ions and repels dissolved salts Already on the market, this membrane enables desalination with lower energy costs than reverse osmosis University of California, Los Angeles and NanoH2O

Nanofiltration membrane Membrane made up of polymers with a pore size ranging from 0.1 to 10nm Field tested to treat drinking water in China and desalinate water in Iran, using this membrane requires less energy than reverse osmosis Saehan Industries, Korea

Nanomesh waterstick A straw-like filtration device that uses carbon nanotubes placed on a flexible, porous, material The waterstick cleans as you drink. Doctors in Africa are using a prototype and the final product will be made available at an affordable cost in developing countries Seldon Laboratories, United States

World filter Filter using a nanofibre layer, made up of polymers, resins, ceramic and other materials, that removes contaminants Designed specifically for household or community-level use in developing countries. The filters are effective, easy to use and require no maintenance KX Industries, United States

Pesticide filter Filter using nanosilver to adsorb and then degrade three pesticides commonly found in Indian water supplies Pesticides are often found in developing country water supplies. This pesticide filter could provide a typical Indian household with 6000 litres of clean water over one year Indian Institute of Technology in Chennai, India, and Eureka Forbes Limited, India

Risks and opportunities

Any assessment of future markets for nanotechnology-based water treatments must take account of both the risks and opportunities.

Some researchers claim that investigations into the ethical, legal and social implications of nanotechnology are lagging behind the science. They quote the low number of citations on such topics in the literature and the fact that, in the United States at least, not all available research funds are being used. For example, the US National Nanotechnology Initiative allocated US$16–28 million to research on nanotechnology's broader social implications — but spent less than half that amount.

And the generally lower scientific capacity in developing countries means it is likely that effective regulation of the ethics and risks of nanotechnologies will lag behind the developed world. Yet there are signs that the ethics of using nanotechnology for clean water are being discussed.

Some researchers have called for more research on the potential health and environmental risks of using nanotechnology for water treatment. For example, there are concerns that the enhanced reactivity of nanoparticles makes them more toxic. Their small size also means they could be hard to contain, so could more easily escape into the environment and potentially damage aquatic life. The full effects of exposure to nanomaterials — from handling them at water treatment plants or drinking them in treated water — are as yet unknown.

But we can make a distinction, in terms of risk assessment, between active and passive nanoparticles. Passive particles, such as a coating, are likely to present no more or less a risk than other manufacturing processes. But active nanoparticles that can move around the environment lead to risks associated with control and containment.

So can nanotechnologies really help solve water problems in developing countries? There are two positive signs that they will. First, water professionals and scientists are increasingly including local communities in dialogues to understand the problems with, and opportunities for, applying nanotechnology to water improvements.

Second, since the commercialisation of nanotechnology is at an early stage, we can hope that such discussions — between researchers, communities and industry — will encourage scientists and businesses to develop appropriate business models to exploit their inventions.

David J. Grimshaw is head of Practical Action's international programme in new technologies and new technologies consultant for SciDev.Net.

Source: Brookheaven National laboratory

Chemical World

2009-09-10T02:48:00.000+08:00

Major step towards extremely sensitive chemical sensors

Together with colleagues from the Netherlands, Russia and Austria, researchers of TU/e gained a better understanding of the mechanism behind charge transport in SAMFETs. This opens the door to extremely sensitive chemical sensors, that could be produced in a cost-effective way. The findings were published online in Nature Nanotechnology.

Atomic force microscopy image of island growth in between two electrodes (left and right) of the SAMFET. The self-assembled monolayer islands, in the middle of the figure, conduct charges. In this case, no path is formed between the two electrodes and therefore current cannot flow. The height of the molecules is 3 nanometers; the length of the gap between the electrodes (i.e. the transistor channel length) is 5 microns.

The research was done at Philips Research Eindhoven and Eindhoven University of Technology.

SAMFETs

The SAMFET is a recent example of the development of ‘plastic micro-electronics’- i.e. electronics based on organic materials. Last year, Philips Research managed to build such a transistor by immersing a silicon substrate into solution containing liquid crystalline molecules that self-assemble onto this substrate, resulting in a semi-conductive layer of just a single molecule thick. The monolayer of the SAMFET consists of molecules that are standing upright. Conduction takes place by charges jumping from one molecule to the other.

However, in previous attempts to make a SAMFET, it was observed that as the length of the SAMFET increased, its level of conductivity counterintuitively decreased exponentially. In a joint project Philips Research, the Eindhoven University of Technology (TU/e), the University of Groningen, the Holst Centre, the Enikolopov Institute for Synthetical Polymer Materials in Moscow and the Technical University in Graz, Austria discovered that this decrease is determined by the monolayer coverage, which could be explained with a widely applicable two-dimensional percolation model.

The ultimate chemical sensor

One could compare this to crossing a river by jumping from rock to rock. The closer the rocks are to each other, the quicker one can jump or even walk to the other river bank. So if the monolayer displays more voids, the conductivity decreases dramatically. Up till now, this behavior was an uncharted area and inhibited the use of SAMFETs in applications such as sensors and plastic electronics. The SAMFET’s extreme sensitivity could open doors to the development of the ultimate chemical sensor, the research team points out. “If we go back to that river again, another benefit of a SAMFET becomes clear”, Martijn Kemerink, assistant professor at the TU/e indicates. “Imagine that there are just enough rocks to cross that river. When you remove just one rock, the effect is significant, for it is impossible to make it to the other side of the river. The SAMFET could be used to make sensors that give a large signal that is triggered by a small change”, he continues.

Future steps

At present, SAMFETs are not widely used, for there are alternatives of which the production process is well-established. However, the production process of SAMFETs is extremely simple and material efficient. The transistor requires only a single layer of molecules that is applied by simple immersion into a chemical solution. The same solution can be used for many substrates, for the substrate only takes the necessary (small) amount of molecules. This makes future large-scale production of monolayer electronics efficient, simple and cost-effective.

Publication

The publication “Monolayer coverage and channel length set the mobility in self-assembled monolayer field-effect transistors”, by Matthijssen et al. can be found at http://www.nature.com/nnano/journal/vaop/ncurrent/abs/nnano.2009.201.html.

The research was conducted at Philips Research Eindhoven and Eindhoven University of Technology. It was funded by STW, ONE-P, the Austrian Nanoinitiative en H.C. Starck GMBH.

Contact: Jim Heirbaut, Communicatie Expertise Centrum, tel. 040 – 247 21 10, e-mail J.Heirbaut@remove-this.tue.nl

Source: Technische Universiteit Eindhoven

Energy and Fuel

2009-09-10T02:14:00.000+08:00

Bioethanol's Impact On Water Supply 3 Times Higher Than Once Thought

At a time when water supplies are scarce in many areas of the United States, scientists in Minnesota are reporting that production of bioethanol — often regarded as the clean-burning energy source of the future — may consume up to three times more water than previously thought. Their study appeared in ACS' journal Environmental Science & Technology.

Sangwon Suh and colleagues point out in the study that annual bioethanol production in the U.S. is currently about 9 billion gallons and note that experts expect it to increase in the near future. The growing demand for bioethanol, particularly corn-based ethanol, has sparked significant concerns among researchers about its impact on water availability . Previous studies estimated that a gallon of corn-based bioethanol requires the use of 263 to 784 gallons of water from the farm to the fuel pump. But these estimates failed to account for widely varied regional irrigation practices, the scientists say.

The scientists made a new estimate of bioethanol's impact on the water supply using detailed irrigation data from 41 states. They found that bioethanol's water requirements can be as high as 861 billion gallons of water from the corn field to the fuel pump in 2007. And a gallon of ethanol may require up to over 2,100 gallons of water from farm to fuel pump, depending on the regional irrigation practice in growing corn. However, a dozen states in the Corn Belt consume less than 100 gallons of water per gallon of ethanol, making them better suited for ethanol production. "The results highlight the need to take regional specifics into account .

Source: american chemical society

ebooks

2009-09-07T23:45:00.000+08:00

Science of everything - by Steve miller

Here is the book which will tell you about some very basics of science..why things happen and how they happen.Why are most plants green?' Why doesn't stomach acid dissolve the stomach itself? Why are there more tornados in the Midwest than on the coast? This volume answers these questions and over 200 more, shedding light on the science behind them. As informative as it is entertaining, it addresses every major branch of science, including physics, chemistry, biology, geology, meteorology, astronomy, and cosmology. It highlights some of the big ideas that helped shape science as we know it, and discusses the future of science with regards to nanotechnology, genetic modification, molecular medicine, and string theory.

Click this link to download the ebook.
http://www.ziddu.com/download/6389314/TheCompleteIdiotsGuidetotheScienceofEverything.rar.html

Science History

2009-09-07T22:51:00.000+08:00

What happened in history of science on 7 September.................

September 7th is Friedrich August Kekulé von Stradonitz's birthday. Kekulé was a German theoretical chemist who figured out how carbon atoms could have a valence of 4 and join together to make long isomers or even rings. He was the first to discover the ring structure of benzene and greatly advanced the understanding of organic chemistry and aromatic compounds of the time.

Kekulé wrote about the method of his discovery where he was sitting by the fireplace and started to nod off. He dreamed of atoms arranging themselves in groups of ever increasing size until they became long chains. The chains started to wind and turn like snakes until one snake grabbed its own tail. He woke up suddenly and spent the rest of the night working out the structure.

It just goes to show that if you let your mind wander, you may figure out a solution to a problem. That, or it shows chemists can have some strange dreams
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1991 - Edwin Mattison McMillan died.

Lawrence Berkeley National LaboratoryMcMillan was an American physicist who shares the 1951 Nobel Prize in Chemistry with Glenn Seaborg for their discovery of the first transuranium elements. He created the element neptunium by bombarding uranium with neutrons. He also bombarded uranium with deuterons to create the element plutonium. He also proposed the next step in cyclotron technology called the synchrocyclotron. The original cyclotron design would receive diminished returns as the accelerated charged particles would become relativistic and more massive making them more difficult to accelerate. The synchrocyclotron would adjust the frequency of the accelerating charge to adapt to this change in mass and allow for much more energetic particles.

many more events happened..on this day

2009-09-06T01:30:00.001+08:00

Plasmonic laser puts the squeeze on light

Plasmonic laser in actionResearchers at the University of California at Berkeley claim to have created the smallest semiconductor laser ever. The new nanoscale device can generate light in a space just 5 nm in size, which is 100 times smaller than the spot produced by conventional lasers. The feat could pave the way for a host of applications, including optical computers that use light instead of electrons to process information, biosensors and nanometre-sized photonic circuits.

Normally, light cannot be focused to a spot smaller than half its wavelength – something known as the diffraction limit. However, in recent years, scientists have succeeded in compressing light down to the nanoscale by coupling it to the electrons that oscillate collectively at the surface of metals – called surface plasmons. The resulting excitations of light and electrons are known as "surface plasmon polaritons" or SPPs.

Previous attempts to exploit SPPs to make nanoscale plasmonic lasers failed because the inherent resistance of metals absorbs the SPPs, causing them to dissipate almost immediately after they are generated. This effect becomes worse the tighter the light is bound to the surface.

Hybrid waveguide

Experimental set-upNow, Xiang Zhang and colleagues have overcome this problem by constructing a hybrid device consisting of a cadmium sulphide semiconductor nanowire separated by a 5 nm thick insulating layer from a metallic silver surface. This structure – dubbed a "hybrid plasmonic waveguide" by the researchers – can concentrate light into an area as much as 100 times smaller than a diffraction-limited spot. And, because it is non-metallic, it poses little resistance so that SPPs can survive for longer.

The researchers can then amplify the SPPs present by shining light onto the structure. "We are able to do this because the nanowire essentially acts an amplifier for nanoscale light," team member Rupert Oulton told physicsworld.com. "This is something that scientists have been trying to achieve for about six years now and is an important milestone for turning the science of nanoscale light into technology."

The result is all the more exciting because it has been demonstrated with semiconductor materials, which are fully compatible with modern electronic device engineering, he added.

Sniffing out single molecules
The most interesting applications to come out of this research will be those that take advantage of the nanoscale light produced. For example, the interactions between light and matter could be strengthened, which means that very weak effects might be observable. This could come in handy for detecting single molecules, allowing for extremely sensitive biodetection, said Oulton.

This is something that scientists have been trying to achieve for about six years now and is an important milestone for turning the science of nanoscale light into technology.

Rupert Oulton, University of California, Berkeley

"We have also shown that the plasmon laser is very efficient so it could operate in a similar way to a conventional laser," he explained. "The ultra-small size of the light would increase the speed of optical telecommunications, while the compact dimensions of the device would allow you to pack and modulate thousands of these tiny light transmitters onto a single chip." Such schemes are promising since computers are fast reaching the speed limitations of electronics and will need to move to optics for a significant leap forward, he said.

The new device follows hot on the heels of another nanolaser, the "spaser", developed by researchers from Purdue, Cornell and Norfolk State universities. Here, a dye coupled to gold spheres just 44 nm across immersed in solution generates surface plasmons when exposed to light.

Quantum World

2009-09-04T23:51:00.000+08:00

Optical 'quantum computer chip' performs first calculation

Researchers at the University of Bristol in the UK have made a prototype optical quantum computer chip and used it to perform a mathematical calculation for the first time. The device consists of tiny silica waveguides on a silicon chip and carries out a version of the quantum calculation known as Shor's algorithm. The result is an important step towards making practical, real-world quantum computers, says the team.

Jeremy O'BrienThe team used the chip to calculate the prime factors of 15 to output the answer 3 and 5. Finding prime factors is a crucial part of modern encryption schemes, such as those employed for secure internet communications.

While classical computers store and process information as "bits" that can have one of two states – "0" or "1" – a quantum computer exploits the ability of quantum particles to be in "superposition" of two or more states at the same time. Such a device could, in principle, outperform a classical computer on some tasks. In practice, however, physicists have struggled to create even the simplest quantum computers because the fragile nature of quantum bits – or qubits – makes them very difficult to transmit, store and process.

Ideal qubits
Photons are a popular choice for qubits because they can travel great distances through optical fibres or even air without losing their quantum nature. This is because individual photons do not normally interact with each other. However, this also means that it is difficult to make devices for processing quantum information, such as logic gates, which rely on two or more photons interacting.

In 2003 Jeremy O'Brien, with colleagues at the University of Queensland, Australia, overcame this problem by building the first controlled NOT (CNOT) quantum logic gate for single photons. A CNOT gate has two inputs – "target" and "control" – and is thought to be a fundamental building block of any quantum computer. However, this first gate was made using conventional optical components, such as mirrors and beam splitters, and took up an entire laboratory bench.

A newer version, developed last year by O'Brien at Bristol, contained hundreds of versions of the same CNOT gate in a piece of silicon just a millimetre in size. This device used coupled waveguides – micron-wide channels of transparent silica that can be grown on silicon substrates using well established industrial processes – instead of mirrors and beam splitters.

First maths calculation
The team has now taken this work a step further by making the device perform the first mathematical calculation. Four photons travel through the waveguides and structures called H gates then prepare each qubit in a superposition of 0 and 1, so that the entire state is a superposition of all four-bit inputs. The calculation is then performed by two other, CZ, gates that create a highly entangled output state. Measuring the output states of the first two qubits produces the results of the calculation.

The computation is done using Shor's algorithm, named for mathematician Peter Shor who invented it in 1994. In his work Shor predicted that quantum computers could factor numbers exponentially faster than their classical counterparts.

"Although this task could be done much faster by any school kid, ours is a really important proof-of-principle demonstration," said team member Alberto Politi of the University of Bristol.

"The really exciting thing about the result is that it will enable the development of large scale quantum circuits, which opens up all kinds of possibilities," added O'Brien.

Nanotechnology Research Revolutionizing How Computers Work

2009-08-21T22:59:00.000+08:00

The London Centre for Nanotechnology (LCN) - a joint venture between UCL and Imperial College London - is leading two international projects to develop radically new approaches to miniaturising computer systems, which would require less energy and make data storage completely stable, among other benefits.
A nanotechnology researcher at work
The technology, known as 'spintronics', is based on exploiting the magnetic 'spin' properties of individual molecules or atoms as well as the electronic charges at this level in metals and other materials used in traditional electronics.
The LCN researchers will work with colleagues at Peking University and Tsinghua University to investigate molecular nanospintronics and with the University of Surrey to investigate silcon-based spintronics. The projects are both funded by the UK Engineering and Physical Sciences Research Council (EPSRC) and the Natural Science Foundation of China.
Professor Gabriel Aeppli, Director of the LCN, said: “These projects will take our collaborations with two top Chinese universities to new heights. China is an emerging powerhouse of advanced research and by collaborating with scientists from around the world, the LCN is driving nanotechnology forwards.”
The researchers aim to reach an in-depth understanding of the nanoscale electronic, magnetic, and structural properties of novel spintronic systems made from ultra-small silicon and organic structures. Recent advances in scanning probe microscopy, pioneered by the team's members, will make the exploration of these systems at the single atom or molecule scale possible.
The two spintronics projects add to UCL's portfolio of collaborative projects with China. One recent example is the 'Fourth Generation Wireless Communication' project, under the EPSRC's UK-China Science Bridges Scheme, which will aim to facilitate scientific exchange, rapid technology development and the commercialisation of new wireless communication technologies. Another project, being carried out under the EPSRC's Collaborative Research with China on Cleaner Fossil Fuels Scheme, aims to develop multifunctional nanostructures that can effectively capture carbon dioxide and harmful pollutants in coal-fired power stations

love and peace
Abhinav