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Report: CO2 could be stored under towns

Published: Oct. 10, 2009 at 12:50 PM

LONDON, Oct. 10 (UPI) — Britain must consider storing millions of tons of the potentially deadly greenhouse gas carbon dioxide beneath cities to slow climate change, a geologist says.

“The worst-case scenario would be a situation where people were unaware there had been a leak. In particular weather conditions or in confined spaces, those people could suffer asphyxiation,” said Nick Riley, head of science policy at the British Geological Survey.

Riley, who advises the government on carbon storage, said the most geologically suitable areas are in Dorset, Hampshire, Gloucestershire, Cheshire, Norfolk and Lincolnshire.

The sites would be monitored to detect leaks, but bedrooms on ground floors might be prohibited because of the risk of the gas poisoning people as they slept, Riley told The Times of London in a story published Saturday.

Britain has proposed storing carbon dioxide
under the North Sea, but that might not be as practical as onshore storage, he said.

“Onshore storage can be much cheaper because you don’t have the transport costs or the problem of building long pipelines, but then you have to persuade people it is safe,” Riley said.

The risk of leakage would be the highest while the gas was being pumped under strong pressure into layers of porous rock 2,600 feet underground, Riley said. The gas would react with the rock and form more stable carbonates over time, he said.

http://www.upi.com/Science_News/2009/10/10/Report-CO2-could-be-stored-under-towns/UPI-19301255193409/#comments

**

Comment I made on this story – 10-10-09

cricketdiane  40 minutes ago
Don’t let them do that. After seeing what the “killer lakes” have done as a result of CO2 – why would we even consider storing it underground? The most sensible solution to CO2 and other carbon sequestration is to harness it for use as a fuel or some other industrial / transportation / electricity generating use. That is the only way that the problem will be solved quickly, efficiently, economically and in a reasonable manner which takes into account the public safety, today and in the future.

And, somebody please find a way for these scientists with their specific language and specialized jargon of their areas of expertise to be able to talk with one another across the lines of their specialties. It really is going to take what they can know and understand of each other’s work, not just that of their narrowly defined field of knowledge.

Thanks,
– cricketdiane

***

Sun-powered device converts CO2 into fuel

Powered only by natural sunlight, an array of nanotubes is able to convert a mixture of carbon dioxide and water vapour into natural gas at unprecedented rates.

Such devices offer a new way to take carbon dioxide from the atmosphere and convert it into fuel or other chemicals to cut the effect of fossil fuel emissions on global climate, says Craig Grimes, from Pennsylvania State University, whose team came up with the device.

Although other research groups have developed methods for converting carbon dioxide into organic compounds like methane, often using titanium-dioxide nanoparticles as catalysts, they have needed ultraviolet light to power the reactions.

The researchers’ breakthrough has been to develop a method that works with the wider range of visible frequencies within sunlight.

Enhanced activity

The team found it could enhance the catalytic abilities of titanium dioxide by forming it into nanotubes each around 135 nanometres wide and 40 microns long to increase surface area. Coating the nanotubes with catalytic copper and platinum particles also boosted their activity.

The researchers housed a 2-centimetre-square section of material bristling with the tubes inside a metal chamber with a quartz window. They then pumped in a mixture of carbon dioxide and water vapour and placed it in sunlight for three hours.

The energy provided by the sunlight transformed the carbon dioxide and water vapour into methane and related organic compounds, such as ethane and propane, at rates as high as 160 microlitres an hour per gram of nanotubes. This is 20 times higher than published results achieved using any previous method, but still too low to be immediately practical.

If the reaction is halted early the device produces a mixture of carbon monoxide and hydrogen known as syngas, which can be converted into diesel.

Copper boost

“If you tried to build a commercial system using what we have accomplished to date, you’d go broke,” admits Grimes. But he is confident that commercially viable results are possible.

“We are now working on uniformly sensitising the entire nanotube array surface with copper nanoparticles, which should dramatically increase conversion rates,” says Grimes, by at least two orders of magnitude for a given area of tubes.

This work suggests a “potentially very exciting” application for titanium-dioxide nanotubes, says Milo Shaffer, a nanotube researcher at Imperial College, London. “The high surface area, small critical dimensions, and open structure [of these nanotubes] apparently provide a relatively high activity,” he says.

Journal Reference: Nano Letters (DOI: 10.1021/nl803258p)

http://www.newscientist.com/article/dn16621-sunpowered-device-converts-co2-into-fuel.html

***

Catalyst could help turn CO2 into fuel

A new catalyst that can split carbon dioxide gas could allow us to use carbon from the atmosphere as a fuel source in a similar way to plants.

“Breaking open the very stable bonds in CO2 is one of the biggest challenges in synthetic chemistry,” says Frederic Goettmann, a chemist at the Max Planck Institute for Colloids and Interfaces in Potsdam, Germany. “But plants have been doing it for millions of years.”

Plants use the energy of sunlight to cleave the relatively stable chemical bonds between the carbon and oxygen atoms in a carbon dioxide molecule. In photosynthesis, the CO2 molecule is initially bonded to nitrogen atoms, making reactive compounds called carbamates. These less stable compounds can then be broken down, allowing the carbon to be used in the synthesis of other plant products, such as sugars and proteins.

In an attempt to emulate this natural process, Goettmann and colleagues Arne Thomas and Markus Antonietti developed their own nitrogen-based catalyst that can produce carbamates. The graphite-like compound is made from flat layers of carbon and nitrogen atoms arranged in hexagons.

The team heated a mixture of CO2 and benzene with the catalyst to a temperature of 150 ºC, at about three times atmospheric pressure. In a first step, the catalyst enabled the CO2 to form a reactive carbamate, like that made in plants.

Oxygen grab

The catalyst’s next useful step was to enable the benzene molecules to grab the oxygen atom from the CO2 in the carbamate, producing phenol and a reactive carbon monoxide (CO) species.

“Carbon monoxide can be used to build new carbon-carbon bonds,” explains Goettmann. “We have taken the first step towards using carbon dioxide from the atmosphere as a source for chemical synthesis.”

Future refinements could allow chemists to reduce their dependence on fossil fuels as sources for making chemicals. Liquid fuel could also be made from CO split from CO2, says Goettmann. “It was common in Second World War Germany and in South Africa in the 1980s to make fuel from CO derived from coal,” he adds.

The researchers are now trying to bring their method even closer to photosynthesis. “The benzene reaction currently supplies the energy that splits the CO2,” Goettmann says, “but in plants it is light.” The new catalyst absorbs ultraviolet radiation, so the team is experimenting to see if light can provide the energy instead.

Recycled carbon

Joe Wood, a chemical engineer at Birmingham University in the UK, is also researching ways of fixing CO2. “There’s growing interest in using it as a recycled input into the chemical industry,” he says.

The Max Planck technique has only been demonstrated on a small scale and it has a low yield of 20%, he points out. “But it looks quite promising,” he adds. “The catalyst can be made cheaply and it works at a relatively low temperature.”

The products of the technique are well suited to making drugs or herbicides, says Wood, “so hopefully they can improve the efficiency and scale it up.”

Reference: Angewandte Chemie (vol 46, p 1) DOI:10.1002/anie.200603478

http://www.newscientist.com/article/dn11390-catalyst-could-help-turn-cosub2sub-into-fuel.html

***

Scientists Use Sunlight to Make Fuel From CO2

By Chuck Squatriglia Email 01.04.08

Sandia researcher Rich Diver checks out the solar furnace which will be the initial source of concentrated solar heat for converting carbon dioxide to fuel. Eventually parabolic dishes will provide the thermal energy.
Photo: Randy Montoya / Sandia National Laboratories

Researchers at Sandia National Laboratories in New Mexico have found a way of using sunlight to recycle carbon dioxide and produce fuels like methanol or gasoline.

The Sunlight to Petrol, or S2P, project essentially reverses the combustion process, recovering the building blocks of hydrocarbons. They can then be used to synthesize liquid fuels like methanol or gasoline. Researchers said the technology already works and could help reduce greenhouse-gas emissions, although large-scale implementation could be a decade or more away.

“This is about closing the cycle,” said Ellen Stechel, manager of Sandia’s Fuels and Energy Transitions department. “Right now our fossil fuels are emitting CO2. This would help us manage and reduce our emissions and put us on the path to a carbon-neutral energy system.”

The idea of recycling carbon dioxide is not new, but has generally been considered too difficult and expensive to be worth the effort. But with oil prices exceeding $100 per barrel and concerns about global warming mounting, researchers are increasingly motivated to investigate carbon recycling. Los Alamos Renewable Energy, for example, has developed a method of using CO2 to generate electricity and fuel.

S2P uses a solar reactor called the Counter-Rotating Ring Receiver Reactor Recuperator, or CR5, to divide carbon dioxide into carbon monoxide and oxygen.

“It’s a heat engine,” Stechel said. “But instead of doing mechanical work, it does chemical work.”

Lab experiments have shown that the process works, Stechel said. The researchers hope to finish a prototype by April.

The prototype will be about the size and shape of a beer keg. It will contain 14 cobalt ferrite rings, each about one foot in diameter and turning at one revolution per minute. An 88-square meter solar furnace will blast sunlight into the unit, heating the rings to about 2,600 degrees Fahrenheit. At that temperature, cobalt ferrite releases oxygen. When the rings cool to about 2,000 degrees, they’re exposed to CO2.

Since the cobalt ferrite is now missing oxygen, it snatches some from the CO2, leaving behind just carbon monoxide — a building block for making hydrocarbons — that can then be used to make methanol or gasoline. And with the cobalt ferrite restored to its original state, the device is ready for another cycle.

Fuels like methanol and gasoline are combinations of hydrogen and carbon that are relatively easy to synthesize, Stechel said. Methanol is the easiest, and that’s where they will start, but gasoline could also be made.

However, creating a powerful and efficient solar power system to get the cobalt ferrite hot enough remains a major hurdle in implementing the technology on a large scale, said Aldo Steinfeld, head of the Solar Technology Laboratory at the Paul Scherrer Institut in Switzerland, in an e-mail.

He and Stechel said the technology could be 15 to 20 years from viability on an industrial scale.

The Sandia team originally developed the CR5 to generate hydrogen for use in fuel cells. If the device’s rings are exposed to steam instead of carbon dioxide, they generate hydrogen. But the scientists switched to carbon monoxide, so the fuels they produce would be compatible with existing infrastructure.

Stechel said the Sandia team envisions a day when coal-fired power plants might have large numbers of CR5s, each reclaiming 45 pounds of carbon dioxide using reclamation technology currently under development and producing enough carbon monoxide to make 2.5 gallons of fuel. The Sunlight to Petrol process also raises the possibility that liquid hydrocarbon fuels might one day be renewable – provided CO2 reclamation reaches a point where the greenhouse gas can be snatched directly from the air. Such a process is being explored by Global Research Technologies and Klaus Lakner of Columbia University, among others.

http://www.wired.com/science/discoveries/news/2008/01/S2P

***

Carbon Sciences, Inc. (OTCBB: CABN), the developer of a breakthrough technology to recycle carbon dioxide (CO2) emissions into gasoline and other portable fuels, today announced the filing of a patent application for a highly efficient nano-scale CO2-to-fuel reactor, which is the most critical part of the company’s CO2-to-Fuel technology.

The company previously announced several important breakthroughs for the commercial viability of its proprietary CO2-to-Fuel technology including: (1) a low energy enzyme based biocatalytic process, and (2) a proprietary enzyme encapsulation technology that increases the life of key enzymes to reduce the cost of fuel production. Carbon Sciences has now successfully incorporated all of these discrete innovations into a self-contained nano-scale CO2-to-Fuel reactor optimized for the efficient transformation of CO2 and H20 molecules into hydrocarbon molecules that are identical to today’s transportation fuels.

These nano-scale reactors, called Smart Particles™, are the key to achieving a fast reaction time and industrial scale up of the company’s CO2-to-Fuel process. The design of Smart Particles is inspired by the way single-cell organisms work. A Smart Particle is based on the concept of synthetic biology and functions like a highly efficient artificial cell that contains proprietary enzyme processes to serve a single purpose — to absorb CO2 molecules and excrete fuel molecules. The patent application for Smart Particle Technology contains the detailed design of Smart Particles, as well as a proprietary manufacturing process where they self-assemble in solution without any external nano-manufacturing.

Dr. Naveed Aslam, the company’s chief technology officer, commented, “We are very excited about our Smart Particle Technology. Previous enzyme approaches to transform CO2 into fuel work in laboratory experiments, but fall short of a design for industrial scale up. Our Smart Particle Technology is a major breakthrough that solves the scale up problem and will be the key to our industrial scale, low energy, low cost, and highly efficient CO2-to-Fuel process. Based on our initial analysis, each newly created Smart Particle can function for over a year and can transform CO2 into fuel in a reaction time of minutes.”

About Carbon Sciences, Inc.

Carbon Sciences, Inc. is developing a breakthrough technology to transform carbon dioxide (CO2) emissions into the basic fuel building blocks required to produce gasoline, diesel fuel, jet fuel and other portable fuels. Innovating at the intersection of chemical engineering and bio-engineering disciplines, we are developing a highly scalable biocatalytic process to meet the fuel needs of the world. Our solution to energy and climate challenges is a sustainable world of fuel consumption and climate stability by transforming CO2 into fuel. For example, Carbon Sciences’ breakthrough technology can be used to transform CO2 emitted from fossil fuel power plants into gasoline to run cars and jet fuel to fly aircraft. To learn more about the Company, please visit our website at http://www.carbonsciences.com.

Safe Harbor Statement

Matters discussed in this press release contain statements that look forward within the meaning of the Private Securities Litigation Reform Act of 1995. When used in this press release, the words “anticipate,” “believe,” “estimate,” “may,” “intend,” “expect” and similar expressions identify such statements that look forward. Actual results, performance or achievements could differ materially from those contemplated, expressed or implied by the statements that look forward contained herein, and while expected, there is no guarantee that we will attain the aforementioned anticipated developmental milestones. These statements that look forward are based largely on the expectations of the Company and are subject to a number of risks and uncertainties. These include, but are not limited to, risks and uncertainties associated with: the impact of economic, competitive and other factors affecting the Company and its operations, markets, product, and distributor performance, the impact on the national and local economies resulting from terrorist actions, and U.S. actions subsequently; and other factors detailed in reports filed by the Company.

http://pr-usa.net/index.php?option=com_content&task=view&id=276044&Itemid=29

***

Converting CO2 Back to Fuel

14 September 2006

Elcat
ELCAT uses catalysts within carbon nanotubes for the photoelectrochemical conversion of CO2 to hydrocarbon fuels.

Most of the work on reducing the concentration of anthropogenic carbon dioxide in the atmosphere is focused on either reducing the emissions from fossil fuel combustion or capturing and sequestering the resulting carbon dioxide. There is, however, a third possible path: the conversion of CO2 back to a hydrocarbon fuel.

In an invited talk at this week’s National Meeting of the American Chemical Society, Professor Gabriele Centi from the University of Messina provided an overview of an ambitious EU-funded project to use solar energy to power the photoelectrochemical gas-phase conversion of CO2 back to hydrocarbon fuels.

<!––>

It is feasible to convert CO2 to fuel. There is still a long way to go to practical application, but it is a good and interesting direction to go.

—Prof. Gabriele Centi, University of Messina

There have been a number of attempts over the past decades to use solar energy to reduce carbon dioxide (CO2) and water (H2O) into a variety of products, including hydrogen and carbon monoxide for use as a syngas for further processing (e.g., Fischer-Tropsch) as well as direct hydrocarbon products.

Past efforts have found that the rate of recombination is not very high and productivity is very low, according to Prof. Centi. The products formed were lower carbon hydrocarbons—CH4 (methane) and CH3OH (methanol) for example. No hydrocarbon greater than C3 was obtained.

These aqueous phase processes found that the photoreduction of carbon dioxide was in competition with the formation of other reaction products, the formation of which would need to be blocked to develop higher carbon hydrocarbons—i.e., hydrocarbons closer to the liquid fuels used in most engines.

There were also a number of other limits on the processes. But not much had been done in exploring a gas-phase conversion.

The EU provided €875,246 ((US$1.1 million) in funding for ELCAT—electrocatalytic gas-phase conversion of CO2 in confined catalysts—a three-year project under the Sixth Framework Program (6FP) to focus on the gas-phase electrocatalysis of CO2 to Fischer-Tropsch (FT)-like products (C1-C10 hydrocarbons and alcohols). Work began in 2004.

The project was born from the observation that with carbon dioxide confined inside carbon micropores, and electrons and protons allowed to flow to an active catalyst of noble metal nanoclusters, that gaseous carbon dioxide was reduced to a series of hydrocarbons and alcohols. The reaction products were remarkably similar to those of the Fischer-Tropsch (FT) process in which synthetic gas is converted to a series of hydrocarbons (alkanes, alkenes and so on) and water.

Three organizations are involved in addition to the University of Messina, Italy: Fritz-Haber-Institut der Max-Planck-Gesellschaft in Berlin, Germany; Université Louis Pasteur in Strasbourg, France; and University of Patras in Patras, Greece.

The ELCAT approach confines the catalyst particles within carbon nanotubes. The catalyst particles need to be quite small, due to the fact of the high number of electrons that must be transferred to generate the higher hydrocarbons. The number of electrons required is quite high—on the order of 24 for a butanol product, and an average of 46 for C8 to C9.

There is no evolution of hydrogen in this process.

The ELCAT team has found that it is possible to produce higher carbon hydrocarbons (C8 to C9), with productivity depending upon a number of factors such as catalyst, electrolyte and flow rates.

As a closing note, Prof. Centi observed that in addition to its utility on Earth, such a process would be of use for Mars missions that could use Martian resources (CO2 and water) to produce propellant for Earth return as well as life-support consumables.

Resources:

September 14, 2006 in Climate Change, Emissions, Fuels |

http://www.greencarcongress.com/2006/09/converting_co2_.html

(And from among the comments on this article – )

Posted by: Patrick | September 14, 2006 at 07:55 AM

This is what you call enviromentally benign fuels and chemicals that basically incorporate man into the carbon cycle. Rather than have man pump more carbon into the atmosphere, it is theoretically and technically feasible to use carbon dioxide directly to produce methanol or other lower chemicals then convert these into higher products. If you heat municipal solid waste at 1000 degrees in a carbon dioxide environment you get a gas that is predominantly carbon monoxide; carbon monoxide can then be reoxidized to operate turbines, engines, make fuels through FT synthesis and the enflluent can undergo the process infinitely.

(And this one – )

Posted by: An Engineer | September 14, 2006 at 04:53 PM

I like the CO2 Bioreactor MUCH BETTER…
and the technology is ready NOW…
http://www.gs-cleantech.com/product_desc.php?mode=3&media=true

(which yielded this: )

***

C02 Bioreactor

GreenShift’s patented and patent-pending bioreactor process uses thermophillic cyanobacteria to consume carbon dioxide emissions. The organisms use the available carbon dioxide in the emissions and water to grow and give off oxygen and water vapor. The organisms also absorb nitrogen oxide and sulfur dioxide. Once the organisms grow to maturity, they fall to the bottom of GreenShift’s bioreactor where they can be harvested for extraction and conversion into value added carbon neutral products

How it Works
All photosynthetic organisms need the following to live and grow: a supply of CO2, light, a growth media and water with nutrients. GreenShift’s CO2 Bioreactor has the potential to reduce the costs of and technical barriers to managing the flow resources into, through and out bioreactor in a compact and cost-efficient way as compared to other algae bioreactor technologies.

Concentrated CO2 is captured and piped to the bioreactor. The sunlight is then collected using efficient parabolic mirrors that transfer and filter the light to a series of light pipes. The light pipes channel the light into the bioreactor structure where it is distributed and radiated throughout the structure using light panels. The organisms we use require as little as 1.5% direct light which means that our collected light can be distributed over a substantial surface area. Next, a growth media, such as polyester, is inserted between each lighting surface. Water, containing nutrients, continuously cascades down the growth media to facilitate the final required step for optimal growth.

To harvest the new biomass, the flow rate of the water over the growth media is increased slightly to remove a portion of the algae, allowing a portion of algae to remain and to begin the next growth cycle. The removed algae is then collected and routed for conversion into value added carbon neutral products. Our technology is also very flexible and can accommodate a variety of algae types. High starch, high oil, or high cellulose algae can be grown in our bioreactor depending on output requirements.

Pilot Facility
GreenShift’s pilot bioreactor is designed as a mobile demonstration platform to quantify existing benchtop testing results and to refine the design parameters for commercial-scale deployments of the technology at targeted locations.

GreenShift’s commercialization plan for this technology is to co-locate bioreactors at corn ethanol production plants and other fermentation processes where concentrated supplies of carbon dioxide naturally emit and are relatively easy to capture and control. We plan to leverage our existing extraction platform and presence in the U.S. ethanol industry to reduce capital and go-to-market costs.

Efficacy data and other relevant information from our pilot will be provided when it is available. In the meantime, we are seeking qualified early adopter sites for testing and deployment of this technology.

» Request Information

http://www.greenshift.com/product_desc.php?mode=3

***

**

October 9, 2008 — Updated 1343 GMT (2143 HKT)

Turning carbon dioxide into fuel

* Story Highlights
* Californian company testing a revolutionary new method of recycling CO2 into fuel
* Carbon Sciences using biocatalyst technology to transform CO2 into fuel efficiently
* Technology could reduce the millions of tons of CO2 emitted by the energy sector

By Matthew Knight
For CNN

LONDON, England (CNN) — You might have thought that recycling is limited to paper, plastics and glass. Well, think again. A Californian company is developing a new technique for recycling carbon dioxide, or CO2, and turning it back into fuel.
Carbon Sciences are developing a “breakthrough technology” to make fuel out of waste CO2.

Carbon Sciences are developing a “breakthrough technology” to make fuel out of waste CO2.
more photos »

Carbon Sciences believe they have made a breakthrough with their technology, which they say can transform CO2 back into basic fuel building blocks efficiently.

Their biocatalytic process converts CO2 into basic hydrocarbons – C1 (methane) C2 (ethane) and C3 (propane) — which can then be utilized to make higher-grade fuels like gasoline and jet fuel.

“We are very excited by what we’ve seen in the lab. We’ve had some promising results,” Derek McLeish, President and CEO of the Santa Barbara-based company, told CNN.

By employing biocatalysis — using natural catalysts to perform chemical reactions — Carbon Sciences hope to bypass the problem of inefficient energy ratios which can render many CO2 recycling projects pointless.

“We don’t use high temperatures or high pressures, which is a huge advantage in terms of scaling the project up,” McLeish said.

In the future, McLeish envisages Carbon Sciences setting up shop next door to large CO2 emitters — coal, gas-fired plants and oil refineries — recycling concentrated streams of CO2 discharged from fossil fuel plants. Trying to take CO2 out of natural air just wouldn’t be worth it.
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“The beauty of this system is the whole infrastructure to distribute, to market and to use it is already in place,” he said.

The recycling process has five main stages. After rudimentary purification and regeneration of the biocatalysts, the CO2 is transferred to a Biocatalytic Reactor Matrix where mass quantities of biocatalysts function in a matrix of liquid reaction chambers breaking down CO2 and turning it into hydrocarbons.

Liquids are then filtered and gases are extracted through condensers ready for conversion to higher grade fuel.

Carbon Sciences are just one of many companies all over the world who are beavering away trying to find effective methods of renewing CO2. The science is well known, but practical energy effective devices are in short supply.

Scientists at Sandia National Laboratories in New Mexico are exploring the idea of using concentrated solar energy to turn CO2 into fuel. The Sunshine to Petrol project is testing a prototype device called the Counter Rotating Ring Receiver Reactor Recuperator (called CR5 for short) which turns CO2 into carbon monoxide which could then form part of a liquid fuel.

Others, like Michael North, Professor of Organic Chemistry at Newcastle University in the UK, are looking at transforming CO2 into useful chemical compounds called cyclic carbonates for industrial use.

Professor North says recycling CO2 may be more vital for the chemical industries than for fuel production.

“People don’t seem to realize that ten percent of everything that comes out of an oil well doesn’t go to the fuel industry, it drives the chemical industry. So not only are we facing a fuel crisis but the entire chemical industry is likely to cease to exist. So we desperately need to find ways of making basic chemical materials out of CO2 to keep the chemical industries ticking over.

Professor North and his team are currently in discussions with some potential investors. He believes that Carbon Sciences’ program sounds feasible.

“They will need to address issues about how long the biocatalysts are active for before they need replacing. If they only work for a day then you are going to be getting through tons and tons of biocatalyst for each ton of CO2.

“Biocatalyst life span and poisoning — by things like nitrous oxide, sulfur dioxide and other impurities – will be the issues determining how feasible it is and how cost effective it is,” he said.

While McLeish doesn’t envisage his biocatalytic technology being able to service the fuel needs of all motorists, he is confident that it can perform profitably on a smaller scale.

“Transportation uses transportable fuels. We need renewables — wind, tidal — but these are not useable in the transport sector. One of the challenges in the future will be transportation,” he said. “The grand vision here is to take waste, build it into a portable fuel and make it useful.”

McLeish recently presented his ideas to a climate conference at Cambridge University in the UK where they were warmly received. And if all goes to plan the company will start a pilot project in 2009.

The conference also gave him the opportunity to promote another Carbon Sciences venture: turning CO2 into precipitated calcium carbonate. Like Professor North, his target is the industrial sector; in particular the paper, plastics and pharmaceutical manufacturers.

Another potential benefit of recycling CO2 will be the reduction of large scale geosequestration.

The problem of rising CO2 emissions was highlighted again recently with the publication of the Global Carbon Project’s Carbon Budget 2007. Concentrations of atmospheric CO2 have risen to 383 parts per million. A rise of 2.2 ppm on 2006 figures.

Of 28 billion metric tons of CO2 released into the atmosphere, fossil fuel emissions accounted for almost a third.

Although some climate critics might scoff at the idea of recycling CO2 arguing that we should be emitting less rather than recycling a pollutant, reusing it may well prove effective in kick-starting a new carbon market, as well as helping clean up our increasingly polluted planet.

http://edition.cnn.com/2008/TECH/science/10/08/co2.fuel/index.html

***

Welcome to Carbon Market Expo Australasia 2009 China 中文 Japan 日本語

Gold Coast, Australia 26-28 October 2009

To be notified of future Carbon Market Expo dates, register here

Australasia’s premier Trade Fair & Conference for carbon market participants & service providers will be this year’s best opportunity to network with key domestic and international carbon market players, and to develop the strategies ahead of the introduction of Australia’s Carbon Pollution Reduction Scheme to minimise costs and maximise benefits associated with emissions trading

Invited speakers and panelists at Carbon Market Expo Australasia 2009 View all speakers

  • Senator the Hon Penny Wong
    Minister for Climate Change and Water
  • Hon Kate Jones MP
    Queensland Minister for Climate Change and Sustainability
  • Vanessa Guthrie
    Vice President – Sustainable Development, Woodside
  • James Grabert
    Manager, Joint Implementation, Sustainable Development Mechanisms Programme, UNFCCC, Germany
  • John Marlow
    Global Head of Environmental Financial Products, Macquarie Bank, London
  • Garth Taylor
    Trade Commissioner for ASEAN, Austrade, Kuala Lumpur
  • Rodrigo Sales
    Partner, Baker & McKenzie, Sao Paulo, Brazil
  • Scott McGregor
    CFO, Camco Global, London
  • Helen Robinson
    Managing Director, Markit Environmental Registry, New Zealand
  • Robert Hill
    Chair, Australian Carbon Trust, former Australian Environment Minister
  • His Excellency Mr Fernando de Mello Barreto
    Brazilian Ambassador to Australia
  • Tim Harcourt
    Chief Economist, Austrade
  • Sudipta Das
    Global Lead Partner, CDM, Ernst & Young, India
  • Patrick Birley
    Chief Executive, European Climate Exchange, London
  • Geoff Leeper
    Deputy Secretary, Australian Climate Change Regulatory Authority (ACCRA) Group, Australian Department of Climate Change
  • Susie Smith
    Principal Sustainability Advisor, Santos
  • Dr Martin Blake
    Head of Sustainability, Royal Mail Group, London
  • Martijn Wilder
    Partner, Baker & McKenzie
  • Mina Guli
    Vice Chairman, Peony Capital, Beijing

The event is to be hosted by leading carbon market industry associations
Environment Business Australia | Asia-Pacific Emissions Trading Forum
<!– Queensland Government –> Business Gold Coast | Queensland Government

http://www.carbonexpo.com.au/?gclid=CNWvyefEtZ0CFZI52godIw-E_A

***

As of March 2009, carbon dioxide in the Earth’s atmosphere is at a concentration of 387 ppm by volume.[update][1]

Atmospheric concentrations of carbon dioxide fluctuate slightly with the change of the seasons, driven primarily by seasonal plant growth in the Northern Hemisphere. Concentrations of carbon dioxide fall during the northern spring and summer as plants consume the gas, and rise during the northern autumn and winter as plants go dormant, die and decay. Carbon dioxide is a greenhouse gas as it transmits visible light but absorbs strongly in the infrared and near-infrared.

Carbon dioxide has no liquid state at pressures below 5.1 atmospheres. At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78 °C and the solid sublimes directly to a gas above −78 °C. In its solid state, carbon dioxide is commonly called dry ice.

[etc.]

http://en.wikipedia.org/wiki/Carbon_dioxide

***

Go to Science@NASA home page

Candlestick Rocket Ship

The high-tech rocket fuels of the future could be made from a surprisingly low-tech material: candle wax!

NASA
Link to story audio Listen to this story via streaming audio, a downloadable file, or get help.

see captionJanuary 29, 2003: Waiting inside his Mercury capsule for the command that would start the countdown and make him the first American in space, Alan Shepard yelled impatiently, “Let’s light this candle!”

Those words may turn out to be more prophetic than Shepard intended.

Since 2001, NASA’s Ames Research Center has been testing a new rocket fuel made from–believe it or not–candle wax.

Right: A material in household candles, paraffin, could become the environmentally friendly rocket fuel of the future. Image copyright © 2003 Comstock, Inc., all rights reserved.

“We actually ordered the wax for our test firings through a commercial Web site that sells candle wax in bulk,” says Arif Karabeyoglu, who developed the theory behind paraffin-based rocket fuels and is currently a research associate at Stanford University.

“We use the exact same wax found in ‘hurricane’ candles,” he says.

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Safer to handle and better for the environment than today’s solid rocket fuels, this modern twist on an ancient fuel could someday propel sounding rockets and commercial-payload rockets into space. It could even form the heart of a new generation of shuttle solid rocket boosters (SRBs) that would have a key safety feature today’s SRBs lack: an “off” switch.

This may seem a shockingly primitive fuel for 21st Century rocket technology. After all, humans have been burning candles (today often made of “paraffin” wax) for the last five millennia. Why didn’t someone think of using it for rockets before?

As anyone who’s lit a candle knows, paraffin normally burns quite calmly, and it’s difficult to make it burn at all without a wick. By all appearances, it just wasn’t the kind of high-powered, explosive fuel needed to blast a rocket off of the planet!

Working in collaboration with David Altman, currently president of Space Propulsion Group, and Brian Cantwell, a professor at Stanford, Karabeyoglu figured out a way to make paraffin burn three times faster than had ever been achieved before–fast enough to serve as rocket fuel.

see caption In their design, the paraffin burns in the presence of pure oxygen gas. This alone causes it to burn much hotter than it does in air, which is only about 21% oxygen. That much had been done before. Karabeyoglu’s innovation was to blow the oxygen past the melted surface of the paraffin fast enough to “whip up” this surface, like the ocean’s choppy surface on a windy day. The “sea spray” of paraffin droplets that this kicks up burns very rapidly, tripling the combustion rate of the fuel.

Above: That’s no candle flame! This test of the paraffin-based fuel was conducted at NASA’s Ames Research Center. Image courtesy NASA.

More than 40 test firings by the Stanford-Ames collaborative project have shown that the idea works as advertised. That’s good news for the rocket industry, because this paraffin fuel would be much simpler and safer to work with than the toxic, explosive fuels used today.

Just think of a household candle. You can safely carve it, melt it, and mold it. If it’s free from artificial colors or perfumes, you could even lick it or chew on it. You could burn dozens of them in a room with no fear of toxic gases making you sick.

Don’t try any of these things with conventional solid rocket fuels!

One reason for the benign nature of candle wax is that the oxidizer needed for it to burn is separate from the wax itself: air in the case of candles, and pure oxygen for rockets. (Chemically speaking, combustion is the rapid “oxidation” of the fuel, usually by combining with the oxygen gas in the air. That’s why fires go out when deprived of air.) This kind of rocket with a solid fuel and a separate gaseous or liquid oxidizer is called a “hybrid” rocket.

see captionIn contrast, today’s solid-fuel rockets use solid materials such as perchlorate compounds as oxidizers, and the fuel and oxidizer are mixed together before being packed into the rocket. In other words, the fuel is “charged” and ready to explode … not a friendly material to work with.

It’s not friendly for the environment either. When today’s solid fuels burn, they produce the acidic compound hydrogen chloride and other noxious chemicals. When it rains, these compounds find their way into lakes and soils, and the increased acidity can harm plant and animal life.

Paraffin, in contrast, burns cleanly. The only gases left behind are water vapor and carbon dioxide. Rocket launches are still so rare that the total pollution they emit is tiny compared to that from cars, airplanes, and coal-fired power plants. But in the future, as more countries and private companies begin launching people and payloads into space, clean-burning rocket fuels will become an increasingly important environmental issue.

Above: The space shuttle Columbia (STS-107) leaves Earth on Jan. 16, 2003. Photo credit and copyright: Becky Ramotowski.

Using hybrid rockets would make all these rocket launches a bit safer as well.

By controlling the flow of the oxidizing gas, “hybrid rockets … can be throttled over a wide range, including shut-down and restart,” Cantwell said in a prepared statement. “That’s one reason why they could be considered as possible replacements for the shuttle’s current solid rocket boosters that cannot be shut off after they are lit.”

“A hybrid rocket equivalent to the space shuttle’s solid rockets would be about the same diameter, but would be somewhat longer,” Cantwell continues. “One design concept being considered is a new hybrid booster rocket that is able to fly back to the launch site for recharging,” he says, which would save considerable cost and time in preparing the boosters for the next launch.

see captionLeft: NASA and Stanford scientists and engineers work on the testing rig for the new paraffin-based solid rocket fuel. Pictured are (clockwise from bottom-left): Brian Cantwell, Arif Karabeyoglu, Shane De’Zilwa, Rusty Hunt, Dave Yaste, Kent Shiffer, Greg Zilliac. Image courtesy NASA.

However, we won’t be seeing paraffin-based shuttle SRBs for many years to come, if ever, Karabeyoglu says. The technology is still in the demonstration phase, and would likely be used for years on smaller rockets before being considered for NASA’s flagship launch vehicle.

But if the tests continue to go well, the launch director at Mission Control may one day mean it quite literally when she or he says, “All right, enough waiting around … let’s light this candle!”

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Credits & Contacts
Author: Patrick L. Barry
Responsible NASA official: John M. Horack
Production Editor: Dr. Tony Phillips
Curator: Bryan Walls
Media Relations: Steve Roy
The Science and Technology Directorate at NASA’s Marshall Space Flight Center sponsors the Science@NASA web sites. The mission of Science@NASA is to help the public understand how exciting NASA research is and to help NASA scientists fulfill their outreach responsibilities.
Web Links
NASA Ames Research Center — home page

Paraffin fuel press release — more information about this new rocket fuel, from Ames

Paraffin rocket fuel research at Stanford — abstracts from research papers

Classroom paraffin combustion experiment — from Louisiana State University, a step-by-step classroom exercise to determine the heat of combustion of paraffin. Also, an alternate procedure is available here.

How a solid propellant rocket works — from NASA’s Goddard Space Flight Center

Shuttle SRBs — facts about the space shuttle’s current solid rocket boosters

Composition of fuel for shuttle solid rocket boosters: (from Kennedy Space Center) “The oxidizer in the Shuttle solids is ammonium perchlorate, which forms 69.93 percent of the mixture. The fuel is a form of powdered aluminum (16 percent), with an iron oxidizer powder (0.07) as a catalyst. The binder that holds the mixture together is polybutadiene acrylic acid acrylonitrile (12.04 percent). In addition, the mixture contains an epoxy-curing agent (1.96 percent). The binder and epoxy also burn as fuel, adding thrust.”

Houston, are we there yet? — (Science@NASA) NASA is developing a variety of new safe and fast technologies to ropel explorers across the solar system.


Join our growing list of subscribers – sign up for our express news delivery and you will receive a mail message every time we post a new story!!! Moresays 'NASA NEWS' Headlines


THE END

http://science.nasa.gov/headlines/y2003/28jan_envirorocket.htm

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Gravity and Black Holes
Gravity and Black Holes
Curriculum Guide
Select Section Overview The Mission 5-8: Goals & Objectives 5-8: Learning Standards 5-8: Guiding Questions 5-8: Content Resource Document 9-12: Goals & Objectives 9-12: Learning Standards 9-12: Guiding Questions 9-12: Content Resource Document References Annotated References <input type=”SUBMIT” value=”Go There!”>

Co2 Rockets

PURPOSE:
This activity will demonstrate Newton’s Laws of Motion through carbon dioxide powered rockets.

OBJECTIVE:
• Students will articulate that force is a push or pull on an object.
• Students will describe Newton’s Laws using mathematical expressions and give examples that relate to everyday situations as well as locations near black holes.

INTENDED AUDIENCE:
9th-12th grade

TIME REQUIRED:
2 hours

MATERIALS:
• 1 or 2 Film canisters per small group (with lids that attach on the inside of the canister, e.g. Fuji canisters)
• 1/2 Effervescing antacid tablet per rocket launch
Paper rocket template
• Various types of paper (computer, cardboard, tracing, typing etc.)
• Scissors
• Tape
• Eye protection
• Water
• A plate to control the liquid from the rocket
• Paper towels
• Meter sticks and quadrant to measure height of launch
How High worksheet
BACKGROUND INFORMATION:
The rockets the class will create will be using a chemical reaction of the antacid and water, producing CO2. The CO2 will be contained in the film canister where the pressure will build up forcing the cap off the canister (the action) which results in the paper rocket shooting up in the opposite direction (the reaction). The template allows for parts of the rocket to be altered and tested. The alterations will allow students to understand that mass, weight, gravity, and amount of fuel affects actions and reactions. The heavier the rocket, the shorter the distance it will climb. The more massive the object, the more work is needed to imbalance the force of gravity, and therefore, the more fuel is needed. Students could write hypotheses based upon Newton’s Third Law and proceed from there, or the Law could be left for them to “discover”.

PREPARATION:
Constructing the Rocket:
• Cut out the template.
• Wrap the long paper around the film canister, canister top facing towards the floor, and tape the paper rocket together. Do not tape the paper to the canister before wrapping around!
• Form the cone and tape to top of body tube.
• Finish with taping the fins to the base of the body, with the right angle of the fin perpendicular with the base of the rocket.
• Tape 1/2 effervescent tablet to top of film canister.
• Fill film canister 1/2 full with water and place in the bottom of the rocket.
• Fit the lid on the canister and flip it over, standing the rocket on the base, with the top of the canister facing the floor. This will allow for the water and antacid to mix, creating CO2. The CO2 will create pressure inside the tube and shoot the rocket.

Preparing Data:
You may want to have a set of control data ready, from several launches with no variables changed. This can serve for comparison for the students’ findings

PROCEDURE:
1. Define Newton’s Third Law of Motion: For every action, there is an equal and opposite reaction.
2. Discuss how rockets demonstrate this Law of Motion. As the fuel in a rocket is ignited, pressure builds up within the fuel tank and the thrust from the escaping fuel leads to an imbalance of forces. An imbalance of forces causes an action. The action is the burnt fuel pushing out of the rocket toward the ground and the reaction is the rocket being pushed in the opposite direction.
3. Have students work in small groups to test various changes with the rockets. Suggested strategies for student working groups:
• Strategy 1
Assign each group a variable to alter and observe.
Have students make rockets adapting the design above. For example, one group can test how the weight of the paper that the rocket is made from affects the outcome of launch. Another may test the difference between having fins and not having fins on a rocket.
Pose the question “Which is more beneficial and why?”
Have the groups use the scientific method to write a hypothesis, test it, and draw a conclusion. Each group of students should tabulate and graph their data to aid them in drawing conclusions.
As a class, compile a set of data, and discuss what variables were tested and how they altered the action or the reaction of the experiment. Also, you could discuss the importance of doing many trials and finding an average and noting their sources of error.

• Strategy 2
– Discuss with the class the variables in the rocket that may be altered for testing.
– Challenge the small groups to test the variables to find what will allow the rocket to go the highest. They can use the quadrants found at the end of this lesson to find the height for each trial.
– Make the students responsible for supporting their findings and relating them to the action or reaction component of the launch. For example, if the fins are taken away, does it affect the action or the reaction of the rocket?
– As a class, discuss the groups’ findings and decide what makes the rocket the most successful.

EVALUATION:
Have the students write a conclusion about the design variables within the demonstration of Newton’s Third Law of Motion. What were their findings, and how can they apply them to real life situations? Their conclusions should be supported by graphical evidence.

RESOURCES:
For an extension check out Rockets Away.
“Make a Pop Rocket” http://spaceplace.jpl.nasa.gov/rocket.htm.

Also check out NASA’s Teacher’s Guide to Rockets PDF: http://spacelink.nasa.gov/Instructional.Materials/NASA.Educational.Products/Rockets/Rockets.pdf

[from – ]

http://www.adlerplanetarium.org/education/resources/gravity/9-12_gq2-2.shtml

***

Uses

Carbon dioxide bubbles in a soft drink.

Carbon dioxide is used by the food industry, the oil industry, and the chemical industry.[11] It is used in many consumer products that require pressurized gas because it is inexpensive and nonflammable, and because it undergoes a phase transition from gas to liquid at room temperature at an attainable pressure of approximately 60 bar (870 psi, 59 atm), allowing far more carbon dioxide to fit in a given container than otherwise would. Life jackets often contain canisters of pressured carbon dioxide for quick inflation. Aluminum capsules are also sold as supplies of compressed gas for airguns, paintball markers, for inflating bicycle tires, and for making seltzer. Rapid vaporization of liquid carbon dioxide is used for blasting in coal mines. High concentrations of carbon dioxide can also be used to kill pests, such as the Common Clothes Moth.

Industrial production

Carbon dioxide is produced mainly from six processes:[11]

  1. From combustion of fossil fuels and wood;
  2. As a by-product of hydrogen production plants, where methane is converted to CO2;
  3. As a by-product of fermentation of sugar in the brewing of beer, whisky and other alcoholic beverages;
  4. From thermal decomposition of limestone, CaCO3, in the manufacture of lime, CaO;
  5. As a by-product of sodium phosphate manufacture;
  6. Directly from natural carbon dioxide springs, where it is produced by the action of acidified water on limestone or dolomite.

http://en.wikipedia.org/wiki/Carbon_dioxide

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SrlePopovic

This is one of my experiments with hybrid engines I performed with Magnesium and Carbon Dioxide fuel mixture. As you can or can not see on this movie, rocket is very fast, engine is something like pulse motor with great thrust for a short period of time.
It is not easy to see this very fast rocket, but if you carefully watch, it is possible to detect that some high pressurized gases percolated through the faucet and ejected the nose cone. Rocket than continued to fly without nose…
But, pay attention to the scary sound of rocket rather than flight performance.
Category: Howto & Style
Tags:

http://www.youtube.com/watch?v=gmeCX4xcFjM

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What is Plasma Welding ?

Plasma arc welding (PAW) is a advanced version of the tungsten inert gas (TIG) welding process. TIG welding has a free-burning arc, which is unstable and tends to wander in the low current range. With increase in current, the arc power increases and the arc diameter also increases.

This leads to a lack of concentrated power in the work-piece, which results in a bigger seam and a larger heat-affected zone. Unlike TIG-welding torches, PAW uses a constricting nozzel and employs two separate gas flows, which give rise to a concentrated plasma arc having a narrow columnar shape.

The plasma column is now stabilized along the axis of the electrode and is more intense than the TIG-welding arc. The column temperature is 10,000-24,000 K compared to 8,000-18,000 K in case of TIG-welding.

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ARCRAFT PW 200 and PW 400 Plasma welding machines operational capabilities

Arc Modes in Plasma Welding
1. Manual plasma-arc welding is usually adapted to non key hole fusion type welding.

2. Mechanized plasma-arc welding is required for high current plasma-arc applications such as making key hole-mode welds or high current filler passes. Metals welded by these processes: Weld unalloyed, low alloy and high
alloy steels, nickle, copper, titanium, zircon and their alloys and special
materials.

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Welded Coupon of 5mm SS Plate completed in one single pass using Key hole Plasma process

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The Plasma-keyhole welding process

The Plasma-keyhole method is a welding process where the gas flow is restricted through a reduction of the gas orifice. This increases the gas velocity and the arc temperature. The plasma arc blows a hole through the joint or the plate. Behind the hole the molten metal flows together filling the hole, due to the gravity forces, surface tension and the gas pressure from the shielding gas.

The advantage of the Plasma-keyhole technique is the ability to weld simple I-butt joints in one single run up to a plate thickness of 8 mm. This will greatly improve welding efficiency. An other advantage is the limited distortion obtained with the process due to the even distribution of heat through the plate thickness.

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Joint preparation for different welding processes



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Welding speed (cm/min.)

Example of productivity gain with carbon steel (5mm):

– MMAW: preparation + 2 passes at 15 to 20 cm/min +slag   removal + grinding.
– Manual TIG: preparation + 2 passes at 10cm/min.
– Key hole plasma: 1 pass at 40 cm/min.

Thickness (mm) Plasma cm/min
3
50
4
35-40
6
25-30
8
15-20

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Approximate heat input for different welding process

Maximum plate thickness that can be welded in one pass without preparation using plasma process :
Carbon steel and stainless steel, austenitic up to 8 mm, titanium up to 10 mm.

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Cost of Welding with TIG/Plasma

In thicknesses from 2.5 to 10 mm, plasma arc welding (downhand or horizontal- vertical) achieves significant productivity improvements through:

  • reduced preparation time (no welding preparations,   square edge butt Without gap),
  • reduced welding time (single pass),
  • reduced finishing and clean-up times,
  • elimination of rework due to lack of defects.

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Unique Features of ARCRAFT Plasma Welding Machine Model PW 200 and PW 400

1. Designed and manufactured Indigenously for the first time in India.
2. Customization of technical features possible.
3. Programmable Current and Gas Down Slope available for automatic closing of key hole during mechanized welding.
4. Indigenously made spares readily available at reasonable price.
5. Service available all over India.
6. Plasma Gun guaranteed for 6 months and power source guaranteed for 1 year against any manufacturing defect

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User Industries

Aerospace and Space Industries, Cryogenics, Foodstuff and Chemical Industries, Machine and Plant Construction, Automobile, Railway, Ship Construction, Tank, Equipment and Pipeline Construction etc.
* Technical information given in this brochure are to the best of our knowledge, but we do not undertake any responsibility for the use there of.

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Plasma Cutting Machines
For precision cutting of Stainless steel, Aluminium and all other Ferrous and Non-ferrous metals.
Stainless Steel cutting upto 150 mm thick plates.
Straight dross free cuts with minimum kerf width at high speeds.
Mechanised cutting with CNC tables / robots.

More…

PTA Hardfacing & Cladding

PPAW (PTA) is a process that deposits very precise coatings of perfectly controlled alloys on mechanical parts that are subject to intense wear, significantly extending their service life.PTA technology is particularly effective in protection against corrosion, thermal shock and abrasion.

More…

Welding Automation
– Repeatable High quality welding.
– Increase Productivity.
– Decrease dependance on welder skill.

More…

Plasma Welding
-Less sensitivity to changes in Arc length.
– Recessed electrode reduces the possibility of tungsten inclusions in the weld and can substantially increase the period between electrode dressings resulting in increased life.

More…


Micro Plasma Welding Machines

– Precision welding of minature parts
– Controlled Arc at low currents
– Automated welding at low currents.
– With built-in Pilot arcing system.

More…

Micro Tig Welding Machines

Precision welding of minature parts
– Ideal for smaller repair or assembly work.
– Built-in high frequency ignition.

More…

Welding Inverters
Light weight & compact : 80% less weight compared to conventional machines.

Manufacturers of Plasma Powder welding machines (PTA), Hardbanding machines, Column and Boom, Welding positioners and Rotators, Plasma torches & consumables – Welding Inverters, Plasma Cutting Machines, Micro-Tig Welding Machines, Micro Plasma Welding Machines, AC Welding Machines, Mig welding Machines, Shape Cutting Machines, Special Purpose Machines for hardfacing and cladding.

Advantages of Plasma Welding

  1. Less sensitivity to changes in Arc length.
  2. Recessed electrode reduces the possibility of tungsten inclusions in the weld and can substantially increase the period between electrode dressings resulting in increased life.
  3. Weld in a single pass up to 6 mm plates in square butt position and 10 mm plates in only  two passes.
  4. Keyhole mode of welding gives smaller heat affected zone resulting in reduced strength loss at the joint for heat treated metals, promotes less grain growth which gives better ductility.
  5. Reduced weld time results in less embrittlement by carbides and complex intermetallic compounds for stainless steel and super alloys.
  6. Equalization of distortion stresses results in less residual stress.
  7. Less filler metal required in keyhole mode significantly reduces porosity.

http://www.arcraftplasma.com/welding/plasma-welding.htm

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Plasma Arc Welding

Introduction:
Plasma welding a modern high quality welding process which is very similar to TIG as the arc is formed between a pointed tungsten electrode and the workpiece. Plasma welding has greater energy concentration and can permit higher welding speeds or less distortion. Additionally plasma welding greater torch standoff. Plasma welding also has improved arc stability. Out of position welding is simpler with plasma welding.

WHAT IS PLASMA?
Plasma is commonly known as fourth state of matter after solid, liquid and gas. This is an extremely hot substance which consists of freeplasma arc welding electrons, positive ions, atoms and molecules. It conducts electricity.
How it works:
By positioning the electrode within the body of the torch, the plasma arc can be separated from the shielding gas envelope. Plasma is then forced through a fine-bore copper nozzle which constricts the arc. There are three operating modes which can be produced by varying bore diameter and plasma gas flow rate:
•Microplasma: 0.1 to 15A.
•Medium current: 15 to 200A.
•Keyhole plasma: over 100A.
The plasma arc is usually operated with a DC, drooping characteristic power source. Because its unique operating features are results of the special torch arrangement and separate plasma and shielding gas flows, a plasma control console can be added on to a normal TIG power source. Full plasma systems are also available. The plasma arc is not stabilised with sine wave AC. Arc reignition is difficult when there is a long electrode to workpiece distance and the plasma is constricted, extreme heating of the electrode during the positive half-cycle causes balling of the tip which can disturb arc stability. Special-purpose switched DC power sources are available. By misbalancing the waveform to reduce the duration of electrode positive polarity, the electrode is kept passably cool to maintain a pointed tip and achieve arc stability.
Although the arc is initiated using HF, it is first formed between the electrode and plasma nozzle. This ‘pilot’ arc is held within the body of the torch until required for welding then it is transferred to the workpiece. The pilot arc system ensures dependable arc starting and, as the pilot arc is maintained between welds, it obtains the need for HF which may cause electrical interference.

Electrode
The electrode used for the plasma process is tungsten-2%thoria and the plasma nozzle is copper. The electrode tip diameter is not as critical as for TIG and should be maintained at around 30-60 degrees. The plasma nozzle bore diameter is critical and too small a bore diameter for the current level and plasma gas flow rate will lead to excessive nozzle erosion or even melting. Large bore diameter should be carefully used for the operating current level.
Because too large a bore diameter, may give problems with arc stability and maintaining a keyhole.
Plasma and shielding gases
The normal combination of gases is argon for the plasma gas, with argon plus 2 to 5% hydrogen for the shielding gas. Helium can be used for plasma gas but because it is hotter this reduces the current rating of the nozzle. Helium’s lower mass can also make the keyhole mode more difficult.

Applications:
Microplasma welding:
Microplasma was traditionally used for welding thin sheets (down to 0.1 mm thickness), and wire and mesh sections. The needle-like stiff arc minimises arc wander and distortion. Although the alike TIG arc is widely used, the newer transistorised (TIG) power sources can produce a very stable arc at low current levels.
Medium current welding:
When used in the melt mode this is a substitute to normal TIG.
The advantages are:
1-Deeper penetration (from higher plasma gas flow).
2-Greater tolerance to surface contamination including coatings (the electrode is within the body of the torch).
The major disadvantage lies in the bulkiness of the torch, making manual welding more difficult. In mechanised welding, greater attention must be paid to maintenance of the torch to ensure consistent performance.


Keyhole welding:

This has several advantages which can be exploited: deep penetration and high welding speeds. Compared with the TIG arc, it can penetrate plate thicknesses up to l0mm, but when welding using a single pass technique, it is more usual to limit the thickness to 6mm. The normal methods is to use the keyhole mode with filler to ensure smooth weld bead profile (with no undercut). For thicknesses up to 15mm, a vee joint preparation is used with a 6mm root face. A two-pass technique is employed and here, the first pass is autogenous with the second pass being made in melt mode with filler wire addition.
As the welding parameters, plasma gas flow rate and filler wire addition (into the keyhole) must be carefully balanced to maintain the keyhole and weld pool stability, this technique is only suitable for mechanised welding. Although it can be used for positional welding, usually with current pulsing, it is normally applied in high speed welding of thicker sheet material (over 3 mm) in the flat position. When pipe welding, the slope-out of current and plasma gas flow must be carefully controlled to close the keyhole without leaving a hole.

http://physicsnobelprize.net/plasma.html

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Plasma arc welding (PAW) is an arc welding process similar to gas tungsten arc welding (GTAW). The electric arc is formed between an electrode (which is usually but not always made of sintered tungsten) and the workpiece. The key difference from GTAW is that in PAW, by positioning the electrode within the body of the torch, the plasma arc can be separated from the shielding gas envelope.

The plasma is then forced through a fine-bore copper nozzle which constricts the arc and the plasma exits the orifice at high velocities (approaching the speed of sound) and a temperature approaching 20,000 °C.

Plasma arc welding is an advancement over the GTAW process. This process uses a non-consumable tungsten electrode and an arc constricted through a fine-bore copper nozzle. PAW can be used to join all metals that are weldable with GTAW (i.e., most commercial metals and alloys). Several basic PAW process variations are possible by varying the current, plasma gas flow rate, and the orifice diameter, including:

  • Micro-plasma (< 15 Amperes)
  • Melt-in mode (15–400 Amperes)
  • Keyhole mode (>100 Amperes)
  • Plasma arc welding has a greater energy concentration as compared to GTAW.
  • A deep, narrow penetration is achievable; reducing distortion and allowing square-butt joints in material up to ½” (12 mm) thick.
  • Greater arc stability allows a much longer arc length (stand-off), and much greater tolerance to arc length changes.
  • PAW requires relatively expensive and complex equipment as compared to GTAW; proper torch maintenance is critical
  • Welding procedures tend to be more complex and less tolerant to variations in fit-up, etc.
  • Operator skill required is slightly greater than for GTAW.
  • Orifice replacement is necessary.

Contents

// <![CDATA[
//

Process variables

Gases

At least two separate (and possibly three) flows of gas are used in PAW:

  • Plasma gas – flows through the orifice and becomes ionized
  • Shielding gas – flows through the outer nozzle and shields the molten weld from the atmosphere
  • Back-purge and trailing gas – required for certain materials and applications.

These gases can all be same, or of differing composition.

Materials

The parts are usually of conductive metals and alloys ranging from 3 mm in thickness to .25 in in thickness. Anything less than the 3 mm may fail due to lack of material and anything more than .25 in. in thickness may experience a failure due to an instability within the weld.

Key process variables

  • Current Type and Polarity
  • DCEN from a CC source is standard
  • AC square-wave is common on aluminum and magnesium
  • Welding current and pulsing – Current can vary from 0.5 A to 1200 A; Current can be constant or pulsed at frequencies up to 20 kHz
  • Gas flow rate (This critical variable must be carefully controlled based upon the current, orifice diameter and shape, gas mixture, and the base material and thickness.)

Other plasma arc processes

Depending upon the design of the torch (e.g., orifice diameter), electrode design, gas type and velocities, and the current levels, several variations of the plasma process are achievable, including:

Plasma arc cutting

When used for cutting, the plasma gas flow is increased so that the deeply penetrating plasma jet cuts through the material and molten material is removed as cutting dross. PAC differs from oxy-fuel cutting in that the plasma process operates by using the arc to melt the metal whereas in the oxy-fuel process, the oxygen oxidizes the metal and the heat from the exothermic reaction melts the metal. Unlike oxy-fuel cutting, the PAC process can be applied to cutting metals which form refractory oxides such as stainless steel, cast iron, aluminum, and other non-ferrous alloys. Since PAC was introduced by Praxair Inc. at the American Welding Society show in 1954, many process refinements, gas developments, and equipment improvements have occurred.

Further reading

  • American Welding Society, Welding Handbook, Volume 2 (8th Ed.)

External links

http://en.wikipedia.org/wiki/Plasma_arc_welding

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[Excerpt from the above article – ]

The plasma is then forced through a fine-bore copper nozzle which constricts the arc and the plasma exits the orifice at high velocities (approaching the speed of sound) and a temperature approaching 20,000 °C.

****

Among the used of CO2 in the wikipedia entry –

Pneumatic systems

Carbon dioxide is one of the most commonly used compressed gases for pneumatic (pressurized gas) systems in portable pressure tools and combat robots.

Fire extinguisher

Carbon dioxide extinguishes flames, and some fire extinguishers, especially those designed for electrical fires, contain liquid carbon dioxide under pressure. Carbon dioxide has also been widely used as an extinguishing agent in fixed fire protection systems for total flooding of a protected space, (National Fire Protection Association Code 12). International Maritime Organisation standards also recognise carbon dioxide systems for fire protection of ship holds and engine rooms. Carbon dioxide based fire protection systems have been linked to several deaths. A review of CO2 systems (Carbon Dioxide as a Fire Suppressant: Examining the Risks, US EPA) identified 51 incidents between 1975 and the date of the report, causing 72 deaths and 145 injuries.

Welding

Carbon dioxide also finds use as an atmosphere for welding, although in the welding arc, it reacts to oxidize most metals. Use in the automotive industry is common despite significant evidence that welds made in carbon dioxide are more brittle than those made in more inert atmospheres, and that such weld joints deteriorate over time because of the formation of carbonic acid. It is used as a welding gas primarily because it is much less expensive than more inert gases such as argon or helium.

Caffeine removal

Liquid carbon dioxide is a good solvent for many lipophilic organic compounds, and is used to remove caffeine from coffee. First, the green coffee beans are soaked in water. The beans are placed in the top of a column seventy feet (21 m) high. Then supercritical carbon dioxide in fluid form at about 93 degrees Celsius enters at the bottom of the column. The caffeine diffuses out of the beans and into the carbon dioxide.

Pharmaceutical and other chemical processing

Carbon dioxide has begun to attract attention in the pharmaceutical and other chemical processing industries as a less toxic alternative to more traditional solvents such as organochlorides. It’s used by some dry cleaners for this reason. (See green chemistry.)

In the chemical industry, carbon dioxide is used for the production of urea, carbonates and bicarbonates, and sodium salicylate.

Agricultural and biological applications

Plants require carbon dioxide to conduct photosynthesis. Greenhouses may (and of large size – must) enrich their atmospheres with additional CO2 to sustain plant life and growth. A photosynthesis-related drop (by a factor less than two) in carbon dioxide concentration in a greenhouse compartment would kill green plants, or, at least, completely stop their growth. At very high concentrations (a factor of 100 or more higher than its atmospheric concentration), carbon dioxide can be toxic to animal life, so raising the concentration to 10,000 ppm (1%) or higher for several hours will eliminate pests such as whiteflies and spider mites in a greenhouse.[12]

It has been proposed that carbon dioxide from power generation be bubbled into ponds to grow algae that could then be converted into biodiesel fuel.[13] Carbon dioxide is already increasingly used in greenhouses as the main carbon source for Spirulina algae. In medicine, up to 5% carbon dioxide (130 times the atmospheric concentration) is added to pure oxygen for stimulation of breathing after apnea and to stabilize the O2/CO2 balance in blood.

Lasers

A common type of industrial gas laser is the carbon dioxide laser.

Polymers and plastics

Carbon dioxide can also be combined with limonene oxide from orange peels or other epoxides to create polymers and plastics.[14]

Oil recovery

Carbon dioxide is used in enhanced oil recovery where it is injected into or adjacent to producing oil wells, usually under supercritical conditions. It acts as both a pressurizing agent and, when dissolved into the underground crude oil, significantly reduces its viscosity, enabling the oil to flow more rapidly through the earth to the removal well.[15] In mature oil fields, extensive pipe networks are used to carry the carbon dioxide to the injection points.

As refrigerants

Liquid and solid carbon dioxide are important refrigerants, especially in the food industry, where they are employed during the transportation and storage of ice cream and other frozen foods. Solid carbon dioxide is called “dry ice” and is used for small shipments where refrigeration equipment is not practical.

Liquid carbon dioxide (industry nomenclature R744 or R-744) was used as a refrigerant prior to the discovery of R-12 and is likely to enjoy a renaissance due to environmental concerns. Its physical properties are highly favorable for cooling, refrigeration, and heating purposes, having a high volumetric cooling capacity. Due to its operation at pressures of up to 130 bars, CO2 systems require highly resistant components that have already been developed for mass production in many sectors.

In automobile air conditioning, in more than 90% of all driving conditions for latitudes higher than 50°, R744 operates more efficiently than systems using R-134a. Its environmental advantages (GWP of 1, non-ozone depleting, non-toxic, non-flammable) could make it the future working fluid to replace current HFCs in cars, supermarkets, hot water heat pumps, among others. Some applications: Coca-Cola has fielded CO2-based beverage coolers and the U.S. Army is interested in CO2 refrigeration and heating technology.[16][17]

By the end of 2007, the global automobile industry is expected to decide on the next-generation refrigerant in car air conditioning. CO2 is one discussed option.(see The Cool War)

Coal bed methane recovery

In enhanced coal bed methane recovery, carbon dioxide is pumped into the coal seam to displace methane.[18]

Wine making

Carbon dioxide in the form of dry ice is often used in the wine making process to cool down bunches of grapes quickly after picking to help prevent spontaneous fermentation by wild yeasts. The main advantage of using dry ice over regular water ice is that it cools the grapes without adding any additional water that may decrease the sugar concentration in the grape must, and therefore also decrease the alcohol concentration in the finished wine.

Dry ice is also used during the cold soak phase of the wine making process to keep grapes cool. The carbon dioxide gas that results from the sublimation of the dry ice tends to settle to the bottom of tanks because it is heavier than regular air. The settled carbon dioxide gas creates an hypoxic environment which helps to prevent bacteria from growing on the grapes until it is time to start the fermentation with the desired strain of yeast.

Carbon dioxide is also used to create a hypoxic environment for carbonic maceration, the process used to produce Beaujolais wine.

Carbon dioxide is sometimes used to top up wine bottles or other storage vessels such as barrels to prevent oxidation, though it has the problem that it can dissolve into the wine, making a previously still wine slightly fizzy. For this reason, other gasses such as nitrogen or argon are preferred for this process by professional wine makers.

pH control

Carbon dioxide can be used as a mean of controlling the pH of swimming pools, by continuously adding gas to the water, thus keeping the pH level from rising. Among the advantages of this is the avoidance of handling (more hazardous) acids.

http://en.wikipedia.org/wiki/Carbon_dioxide

***

Liquid carbon dioxide (industry nomenclature R744 or R-744) was used as a refrigerant prior to the discovery of R-12 and is likely to enjoy a renaissance due to environmental concerns. Its physical properties are highly favorable for cooling, refrigeration, and heating purposes, having a high volumetric cooling capacity. Due to its operation at pressures of up to 130 bars, CO2 systems require highly resistant components that have already been developed for mass production in many sectors.

[excerpt from above]

***

Laser Welding

Laser beam Welding Electron Beam Welding Plasma Arc Welding

Electron Beam Welding:

Introduction:
Electron Beam Welding (EEW) is a unique way of delivering large amounts of concentrated thermal energy to materials being welded. It became viable, as a production process, in the late 1950’s. At that time, it was used mainly in the aerospace and nuclear industries. Since then, it has become the welding technique with the widest range of applications. This has resulted from the ability to use the very high energy density of the beam to weld parts ranging in sizes from very delicate small components using just a few watts of power, to welding steel at a thickness of 10 to 12 inches with 100 Kilowatts or more. However, even today most of the applications are less than 1/2″ in thickness, and cover a wide variety of metals and even dissimilar metal joints

How it works:
The most common Electron Beam systems used in manufacturing today are of the high vacuum design. The other machine types are:
1-Partial vacuum equipment.
2-Non-vacuum equipment.
These two types are used in mass production where high output is important.electron beam welding
The diagram shown, shows the classic triode gun and column assembly. The triode gun design consists of the cathode (Filament), Bias cup (Grid) and Anode. Other sub-assembly components that contribute to the triode are: High voltage insulator Feed-through, high voltage cable and deflection coils. All these components are housed in a vacuum vessel called the upper column. The column assembly is held under a high vacuum by an isolation valve positioned below the anode assembly.
The vacuum environment provides several benefits:
•Removes the bulk gas molecules necessary for a stable triode.
•Provides protection for the incandescent filament against oxidization.
•Provides a controlled environment to protect the gun against welding byproduct.
Beam Formation: Upper Column
The beam formatting begins with the emission of electrons from the incandescently heated tungsten filament.
During this process the filament is saturated by a determined amount of the electrical current. Electrons boil off the filament tip as it reaches operating temperatures and gathers in the grid cup assembly. A negative high voltage potential (acceleration voltage) is applied to the filament cathode assembly, with the cathode assembly charged at 150 kV the only force preventing the electron beam from propagating is a secondary negatively charged voltage that resides on the grid cup or bias assembly. This voltage respectively lower than the accelerating voltage acts as a valve that controls the volume of electron energy that can flow from the cathode emitter to its attracting target. The anode at a positive potential is one of the attracting targets in the triode but its role is more of a beam formation device rather than a collector of electrons. The secondary target is the workpiece which is usually metallic and offers a conductive path to earth to complete the circuit. The electron gun assembly design is a result of some extensive engineering studies and experimentation. Some of the early triode designs were mathematically modeled and their designs still produced today.

Beam Delivery: Lower Column
Other important components of the beam delivery column are the focus and deflection coils and isolation valve. The magnetic focus coil located beneath the anode assembly provides the means for squeezing the beam into a tightly focused stream of energy or can be used to widely dispersed energy resource. The deflection coil is another very important component that will contribute to the latter discussion of beam control parameters but for now we will simply say that it is a steering device. The focus coil is circular in design and is concentric with the column. An electrical current is passed through the coil which produces the resultant magnetic fluxes that act to converge the electron beam. The deflection coil is configured with four separately wound coils positioned at right angles to the column. The four coils are segmented as sets (x and y ) each axis becomes a separate control allowing the energizing of each axis on command, thus steering the beam. Many industrial applications require the precise manipulation of the beam energy so as to provide a pattern for processing. This is usually accomplished by superimposing an AC signal onto the four coils simultaneously therefore creating a specific pattern. The isolation valve serves to isolate the vacuum environment in the upper column from the lower. After the electron beam has passed through the lower column, it enters the chamber cavity. Another important part of the lower column of the (EBW) machine is the viewing optics, the optics are arranged in the lower column in such a manner that when viewing the beam energy through a video camera or magnified optics it gives the view from a parallel plane, giving the viewer the perception of looking down the column.


Beam Interaction in Chamber Cavity:

As the beam enters the chamber cavity it is aimed onto a target material placed at a determined height representative of the actual workpiece. This procedure is typical in most pre-weld set-up requirements. The welding technician would then follow a process of beam alignment and beam parameter calibration. Unlike laser, the preparation is quite different in the fact that the technician must view the actual beam through the optical system in order to verify the beam alignment and focus. With a laser beam, the technician could not view the beam quality and therefore must rely on instrumentation to profile the beam energy. Once the beam has been tuned and calibrated the equipment is now ready for part processing.
The focused beam of electrons is impinged at a targeted location on the weld joint at which point the kinetic energy of the electrons is converted to thermal energy. The workpiece can either be stationary and the beam energy deflected or the workpiece can be traversed along a desired axis of motion. This motion can be computer controlled such as a CNC table, or, simply a rotating mechanism can be employed.
As the beam energy is applied to the moving part several physical transformations take place. The material instantly begins to melt at the surface, then a rapid vaporization occurs followed by the resultant coalescence.

Two welding modes are used in the (EBW):
1-Conductance mode:
Mainly applicable to thin materials, heating of the weld joint to melting temperature is quickly generated at or below the materials surface followed by thermal conductance throughout the joint for complete or partial penetration. The resulting weld is very narrow for two reasons:
a- It is produced by a focused beam spot with energy densities concentrated into a .010 to.030 area.
b- The high energy density allows for quick travel speeds allowing the weld to occur so fast that the adjacent base metal does not absorb the excess heat therefore giving the E.B. process it’s distinct minimal heat affected zone.
2-Keyhole mode:
It is employed when deep penetration is a requirement. This is possible since the concentrated energy and velocity of the electrons of the focused beam are capable of subsurface penetration. The subsurface penetration causes the rapid vaporization of the material thus causing a hole to be drilled through the material. In the hole cavity the rapid vaporization and sputtering causes a pressure to develop thereby suspending the liquidus material against the cavity walls. As the hole is advanced along the weld joint by motion of the workpiece the molten layer flows around the beam energy to fill the hole and coalesce to produce a fusion weld. The hole and trailing solidifying metal resemble the shape of an old fashion keyhole.
Both the conductance and keyhole welding modes share physical features such as narrow welds and minimal heat affected zone .The basic difference is that a keyhole weld is a full penetration weld and a conductance weld usually carries a molten puddle and penetrates by virtue of conduction of thermal energy.

Advantages:
1-Deeper and narrower: Ability to achieve a high depth-to-width ratio eliminating multiple-pass welds.
2-Low heat input: Minimal shrinkage and distortion as well as ability to weld in close proximity to heat sensitive components.
3-Superior strength: Vacuum melt quality can yield 95% strength of base material.
4-Versatility: From .001″ to 3″ deep penetration welds, each performed with exceptional control and repeatability.
5-High purity: Vacuum environment eliminates impurities such as oxides and nitrides.
6-Superior process: Permits welding of refractory metals and combinations of many dissimilar metals not easily weld with conventional welding processes.

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http://physicsnobelprize.net/ebw.html

***

20 Years of Moving Atoms, One by One






Moving Atoms

Watching researchers move atoms can be an unsettling yet wonderful experience: It’s hard to conceive that humans can manipulate things so small that they can barely be called “things.”

But the work environment is quite a bit more prosaic. Today IBM researchers working on atomic science are housed in a cramped room noticeably lacking in flat-panel displays and personal supercomputers. Instead they hunch over a PC running Pentium processors that were popular in the late 1990s. The computer controls a multimillion dollar scanning tunneling microscope and moves its tip around.

Following the fuzzy, pixelized graphics on the monitor that shows the atoms, researchers can zero in on one individual atom, pick it up and drop it in a different location. It’s an experience that has what Eigler calls the “boggle factor.”

“What hits you is the enormity of what you are doing in terms of building at an atomic scale,” says Eigler in this video. “It’s so far from what we could have conceived many years ago.”

IBM spelled by positioning 35 Xenon Atoms.

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http://www.wired.com/gadgetlab/2009/09/gallery-atomic-science/2/

[excerpt from – ]

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20 Years of Moving Atoms, One by One

* By Priya Ganapati Email Author
* September 30, 2009  |
* 8:31 pm  |
* Categories: R&D and Inventions
*

<< previous image | next image >>

Sometimes genius looks like an elegant equation written in chalk on a blackboard. Sometimes it’s a hodgepodge of wires, canisters and aluminum-foil-wrapped hoses, all held together by shiny bolts.

Despite its homebrew appearance, this device, a scanning tunneling microscope, is one of the most extraordinary lab instruments of the last three decades. It can pick up individual atoms one by one and move them around to create supersmall structures, a fundamental requirement for nanotechnology.

Twenty years ago this week, on Sept. 28, 1989, an IBM physicist, Don Eigler, became the first person to manipulate and position individual atoms. Less than two months later, he arranged 35 Xenon atoms to spell out the letters IBM. Writing those three characters took about 22 hours. Today, the process would take about 15 minutes.

“We wanted to show we could position atoms in a way that’s very similar to how a child builds with Lego blocks,” says Eigler, who works at IBM’s Almaden Research Center. “You take the blocks where you want them to go.”

Eigler’s breakthrough has big implications for computer science. For instance, researchers are looking to build smaller and smaller electronic devices. They hope, someday, to engineer these devices from the ground up, on a nanometer scale.

“The ability to manipulate atoms, build structures of our own, design and explore their functionality has changed people’s outlook in many ways,” says Eigler. “It has been identified as one of the starting moments of nanotech because of the access it gave us to atoms, even though no product has comes out of it.”

On the 20th anniversary of Eigler’s achievement, we look at the science, art and implications of moving individual atoms.

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http://www.wired.com/gadgetlab/2009/09/gallery-atomic-science/

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Moving Atoms

Watching researchers move atoms can be an unsettling yet wonderful experience: It’s hard to conceive that humans can manipulate things so small that they can barely be called “things.”

But the work environment is quite a bit more prosaic. Today IBM researchers working on atomic science are housed in a cramped room noticeably lacking in flat-panel displays and personal supercomputers. Instead they hunch over a PC running Pentium processors that were popular in the late 1990s. The computer controls a multimillion dollar scanning tunneling microscope and moves its tip around.

Following the fuzzy, pixelized graphics on the monitor that shows the atoms, researchers can zero in on one individual atom, pick it up and drop it in a different location. It’s an experience that has what Eigler calls the “boggle factor.”

“What hits you is the enormity of what you are doing in terms of building at an atomic scale,” says Eigler in this video. “It’s so far from what we could have conceived many years ago.”

IBM spelled by positioning 35 Xenon Atoms.

Pages: 1 2 3 4 5 6

http://www.wired.com/gadgetlab/2009/09/gallery-atomic-science/2/

atomic_science_3a.jpg

Scanning Tunneling Microscope

At the heart of the atomic experiments is the scanning tunneling microscope that can not only take pictures of individual atoms but also build new structures using those atoms. Two IBM scientists at the company’s Zurich lab, Gerd Binnig and Heinrich Rohrer, created the first tunneling microscope in 1981. Six years later, the inventors won a Nobel Prize.

Here’s how it works. The microscope has a fine tip so sharp that it is just one of two atoms at the point. The tip is brought very near to the surface of a sample. An applied voltage will cause electrons to “tunnel” between the surface and the tip. That means the electrons move beyond the surface of the solid into a short region in space above it. Meanwhile, the tip slowly scans the surface of the sample at a distance equal to the diameter of a single atom. Through the scanning process, the tip maintains the same distance and helps draw a profile of the surface. A computer-generated contour map shows the atomic detail.

When the tip is brought close enough to the sample surface, a strong attractive force is present that can pick up an electron from the surface. To deposit it in another region of the sample, a repulsive force between the tip and the atom is generated.

Eigler built a specialized version of this microscope. His STM allows samples to be prepared and studied in an ultrahigh vacuum and at the temperature of liquid helium, which is just four degrees above absolute zero, or -459 degrees Fahrenheit. The low temperature keeps atoms from flying off the copper surface within the microscope.

“Physicists have to do experiments that require design and building of entirely new instrumentation, something that never exists before,” says Eigler. “It’s part of their training.”

Eigler built the first version of the microscope in about 14 months. “The actual microscope that moves the atoms is not very much larger; it can fit into the palm of the hand,” he says. “But it seems like a big machine because of everything else that was required to maintain very low vibration, high vacuum and excellent electronics to move the atoms.”

Nobel laureates Heinrich Rohrer (left) and Gerd Binnig (right) of IBM’s Zurich Research Laboratory are shown here in 1981 with a first-generation scanning tunneling microscope.

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Tags: atoms, electron microscopes, IBM, microscopes

http://www.wired.com/gadgetlab/2009/09/gallery-atomic-science/3/

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Fun With Single Atoms

Once IBM researchers had the ability to position individual atoms, they had some fun. In 1993, they spelled the Kanji characters for the word atom using iron atoms on a copper surface.

Researchers found it to be so much fun that they started leaving messages for their fellow scientists in the lab STM notebook. Mornings would bring a new figure drawn with manipulated atoms. In one case, a scientist manipulated carbon monoxide on a platinum surface, creating a carbon monoxide man who greeted his lab mates the next morning.

In 1996, The researchers also created the world’s smallest abacus with atoms. The abacus was created out of 10 carbon atoms and was seen as a milestone in nanoscale engineering. Moving the links of the abacus wouldn’t be easy and require the scanning tunneling microscope but with enough time and patience, it could be done.

The world’s smallest abacus with atoms (left), Kanji characters for the word ‘atom’ (center) and a carbon monoxide man were some of the pictures created by moving atoms.

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http://www.wired.com/gadgetlab/2009/09/gallery-atomic-science/4/

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Atomic Force Microscope

The successor to the STM is the atomic force microscope, which researchers use to measure the force needed to move individual atoms.

The atomic force microscope has a miniature “tuning fork” that measures the interaction between the tip of the microscope and the atoms on a surface. When the tip is positioned close to an atom on the surface, the frequency of the tuning fork changes slightly. This change in frequency is analyzed to determine the force exerted on the atom, which can be used for mapping the surface and moving atoms.

Eigler says the business of moving atoms around is fun and his work never gets boring.

“I have developed an unexpected affinity for some of the most common things in the world, like rocks,” he says. “The affinity comes from realizing that’s what I am — just a bunch of atoms. It’s a difficult thing to talk about and explain, but it’s a reaction that is deep, psychological and emotional.”

The atomic force microscope has a tuning fork used to measure the force required to move an atom.

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Tags: atoms, electron microscopes, IBM, microscopes

http://www.wired.com/gadgetlab/2009/09/gallery-atomic-science/5/

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Implications for Nanotechnology

In the last few years, Eigler’s group has built on his work and constructed custom molecules using the STM. They have also constructed and operated an electrical switch whose only moving part is a single atom.

In the “If you can read this, you are too close” image, the letters are just 1 nanometer wide and 1 nanometer tall.

A measure of the impact of this work is in the number of experiments and technical papers today that use atom manipulation as one of their primary scientific tools, says Eigler.

“If you think about it, this is not a manufacturing capability but a powerful technique in the laboratory,” he says. “It lets us do those experiments that give us the knowledge that we would not get otherwise.

“What’s really exciting to watch is that with every passing week, month or year we end up with new discoveries due to our abilities to work with very small structures,” says Eigler. “It’s fair to anticipate that these will have a technological impact on people’s lives very soon.”

These words were created by laying carbon monoxide molecules on a flat copper surface.

All photos courtesy IBM

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Tags: atoms, electron microscopes, IBM, microscopes

http://www.wired.com/gadgetlab/2009/09/gallery-atomic-science/6/

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And from my cards –

Acetylene

a colorless, poisonous, highly flammable gaseous hydrocarbon, CH:CH produced by the reaction of water and calcium carbide: it is used as the starting material in the synthesis of many organic compounds – for lighting and as a fuel with oxygen to produce a hot flame, as in a blowtorch.

and

Chlorophyll, Chlorophyl –

the green pigment found in the chloroplasts of plant cells:  it occurs in two forms

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