March 12, 2006, 9:53 PM CT

Identifying Gems And Minerals

It'll be a snap to identify gemstones once Robert Downs finishes his library of spectral fingerprints for all the Earth's minerals.

Downs is almost halfway there. So far, the associate professor of geosciences at The University of Arizona in Tucson has cataloged about 1,500 of the approximately 4,000 known minerals using a technique called Raman spectroscopy. The effort is known as the RRUFF Project.

"We're developing a tricorder," Downs said, referring to the instrument used on the "Star Trek" television show that could be waved over materials to identify their chemical composition.

Downs' work is destined for space. Eventhough Downs' current Raman spectrometer takes up an area the size of a tabletop, his colleague M. Bonner Denton, a UA professor of chemistry and of geosciences, is developing a pocket-sized Raman spectrometer to be used on the 2009 Mars rover.

Downs is collaborating with George Rossman of the California Institute of Technology in Pasadena to develop the database of minerals.

The technology being developed for Mars will help create handheld instruments for use on Earth.

One use for a hand-held instrument would be the identification of gemstones. Downs and Denton will both give presentations on that aspect of the project on Sunday afternoon, March 12, at the 57th Annual Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy (PITTCON 2006).........

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March 6, 2006, 11:29 PM CT

Running Your Car On Hydrogen

Chemists at UCLA and the University of Michigan report an advance toward the goal of cars that run on hydrogen rather than gasoline. While the U.S. Department of Energy estimates that practical hydrogen fuel will require concentrations of at least 6.5 percent, the chemists have achieved concentrations of 7.5 percent - nearly three times as much as has been reported previously - but at a very low temperature (77 degrees Kelvin).

The research, scheduled would be published in late March in the Journal of the American Chemical Society, could lead to a hydrogen fuel that powers not only cars, but laptop computers, cellular phones, digital cameras and other electronic devices as well.

"We have a class of materials in which we can change the components nearly at will," said Omar Yaghi, UCLA professor of chemistry, who conducted the research with colleagues at the University of Michigan. "There is no other class of materials where one can do that. The exciting discovery we are reporting is that, using a new material, we have identified a clear path for how to get above seven percent of the material's weight in hydrogen".

The materials, which Yaghi invented in the early part of 1990s, are called metal-organic frameworks (MOFs), pronounced "moffs," which are like scaffolds made of linked rods - a structure that maximizes the surface area. MOFs, which have been described as crystal sponges, have pores, openings on the nanoscale in which Yaghi and colleagues can store gases that are commonly difficult to store and transport. MOFs can be made highly porous to increase their storage capacity; one gram of a MOF has the surface area of a football field! Yaghi's laboratory has made more than 500 MOFs, with a variety of properties and structures.........

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February 28, 2006, 11:48 PM CT

Art in Crystallography

This watercolor illustration, entitled Blood 2,000,000X, shows a cross-section through the blood, magnified by about two million times. It received first place in a new competition, called Art in Crystallography, sponsored by the American Crystallographic Association (ACA) Newsletter and the ACA Council. It was created by David Goodsell, an artist and crystallographer at the Scripps Research Institute in California.

Blood serum, the clear fluid part of the blood, is shown in the upper half and a red blood cell in the lower half. In the serum, look for Y-shaped antibodies, long thin molecules of fibrinogen (a protein that helps perform coagulation, in light red) and a number of small albumin proteins (the most common types of proteins in the blood). The large UFO-shaped objects are low density lipoprotein (the "bad" type of cholesterol) and the six-armed protein is complement C1, a protein involved in defense against bacterial infection. The red blood cell is filled with hemoglobin, in red.The cell wall, in purple, is braced on the inner surface by a network of structural proteins, with long chains of spectrin connected together by small segments of actin. (Source: ACA's Art in Crystallography website.).

Source: American Institute of Physics........

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February 28, 2006, 11:43 PM CT

Dumbbell-Shaped Nucleus

Formation of molecular states in 10Be based on the exchange of neutrons (blue) in p-orbits based on alpha-particle cores (red-spheres). The left-hand side shows the arrangement which gives rise to pi-bonds, the right-hand side sigma-schematic.

Source: American Institute of Physics........

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February 27, 2006, 8:10 PM CT

High-Tech Sieve Sifts for Hydrogen

Whether it's used in chemical laboratories or the fuel tanks of advanced automobiles, hydrogen is mostly produced from natural gas and other fossil fuels. However, to isolate the tiny hydrogen molecules, engineers must first remove impurities, and the currently available methods can require substantial equipment or toxic chemicals.

Now, in the Feb. 3 issue of the journal Science, engineers have announced the development of a simpler, safer material that can potentially assist, and in some places replace, existing processing methods. The rubbery, plastic film, similar to membranes already in use in biomedical devices, has applications for isolating not only hydrogen, but also natural gas itself.

"Our team originally set out to design membranes to purify hydrogen produced from coal," said co-author and National Science Foundation awardee Benny Freeman of The University of Texas. "We felt that a good improvement would be to design membranes more permeable to impurities than to hydrogen," he added. Until now, existing membranes had the opposite property--they were more permeable to hydrogen than to impurities.

Freeman collaborated in this research with colleagues at both The University of Texas at Austin and the Research Triangle Institute in Research Triangle Park, N.C.........

Posted by: Kevin      Permalink     

February 26, 2006, 9:16 PM CT
The Chemical Formulary

One more old book from Cpikas! - "The Chemical Formulary - about 15 volumes from 1933 to 1957 with recipes for everything from pyrotechnics to vegetable soup! Includes recipes for hair pomade and flares.... Very, very cool....

The Chemical Formulary: Collection of Commercial Formulas for Making Thousands of Products in Many Fields - Amazon.

Source

February 23, 2006, 11:37 PM CT

Overseas NOx Could Be Boosting Ozone Levels

Large amounts of a chemical that boosts ozone production are being transported to North America from across the Pacific Ocean in May, as per a new report by scientists from Georgia Tech. These higher levels of nitrogen oxides (NOx), arriving in late spring, could be contributing to significant increases in ozone levels over North America. The research appeared in volume 33 of the journal Geophysical Research Letters.

It's well-known that pollutants don't always stay in the region in which they are produced. What's not understood as well is where and when they travel," said Yuhang Wang, associate professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. "Finding this large amount of NOx traveling from across the Pacific is important because it will allow us to build better models so we can better understand how pollutants created in one region of the world are affecting the other regions."

Wang, along with colleagues from Tech, the University of California, Irvine, and the National Center for Atmospheric Research studied data from the Tropospheric Ozone Production about the Spring Equinox (TOPSE) experiment when they found much larger amounts of an array of chemicals, including NOx, and ozone than predicted by current models.........

Posted by: Sarah      Permalink         Source

February 21, 2006, 9:46 PM CT

Finding Safer Alloys

MIT scientists have devised a new method for shrinking the size of crystals to make safer metal alloys. The new materials could replace metal coatings such as chromium, which is dangerous for factory workers to produce.

The method, developed by Associate Professor Christopher Schuh and graduate student Andrew Detor, both of the Department of Materials Science and Engineering, involves making the crystals within an alloy (a combination of two or more metals) smaller and thus harder.

For the chromium replacement, the two made crystals of nickel and tungsten small enough that the resulting alloy is as hard as chromium. The trick is a new twist on electroplating that involves manipulating -- on the nanoscale, or billionths of a meter -- how the nickel and tungsten atoms are laid down as they are plated onto another metal.

While so-called hard chromium is used to coat industrial parts and decorative items such as automobile bumpers, the coating process uses a form of chromium called hexavalent chromium that has been linked to cancer and other adverse health effects if workers inhale it. A steel ring, for example, is coated using a bath of hexavalent chromium that gives off harmful fumes.

While exhaust hoods are used to take away much of the fumes, the federal government currently is considering tougher safety standards for workers exposed to the baths. That has led industrial companies to look for metals that will not give off the harmful fumes. Schuh says the new alloy is one such safer alternative.........

Posted by: Sarah      Permalink         Source

February 21, 2006, 9:21 PM CT

Finding Safer Metals

MIT scientists have devised a new method for shrinking the size of crystals to make safer metal alloys. The new materials could replace metal coatings such as chromium, which is dangerous for factory workers to produce.

The method, developed by Associate Professor Christopher Schuh and graduate student Andrew Detor, both of the Department of Materials Science and Engineering, involves making the crystals within an alloy (a combination of two or more metals) smaller and thus harder.

For the chromium replacement, the two made crystals of nickel and tungsten small enough that the resulting alloy is as hard as chromium. The trick is a new twist on electroplating that involves manipulating -- on the nanoscale, or billionths of a meter -- how the nickel and tungsten atoms are laid down as they are plated onto another metal.

While so-called hard chromium is used to coat industrial parts and decorative items such as automobile bumpers, the coating process uses a form of chromium called hexavalent chromium that has been linked to cancer and other adverse health effects if workers inhale it. A steel ring, for example, is coated using a bath of hexavalent chromium that gives off harmful fumes.

While exhaust hoods are used to take away much of the fumes, the federal government currently is considering tougher safety standards for workers exposed to the baths. That has led industrial companies to look for metals that will not give off the harmful fumes. Schuh says the new alloy is one such safer alternative.........

Posted by: Sarah      Permalink         Source

February 14, 2006, 11:50 PM CT

Speeding Chemical Detection

Researchers at Georgia Tech have created technology capable of detecting trace amounts of biological or chemical agents in a matter of seconds, much faster than traditional methods, which can take hours or up to a day. The system uses reusable hydrogel microlenses so small that millions of them can fit on a one-inch-square plate. It could greatly enhance the ability of authorities responding to a biological or chemical weapons attack as well as increase the speed of medical testing. The research appears in the February 20 edition of the chemistry journal Angewandte Chemie.

The microlenses make use of the antibody-antigen binding, the same process used by the human immune system, to detect biological or chemical agents. When antibodies on the microlenses come into contact with the antigen they are set to detect, they bind, causing the lenses to swell and become less dense. By projecting an image through the tiny lenses, researchers can view this swelling as a change in the microlens' focal length. If the projected image is normally in focus, it goes out of focus when it comes into contact with the substance.

"These are reversible, so you can use the same lenses over and over again. This is the first time someone has done this with microlenses," said L. Andrew Lyon, associate professor in the School of Chemistry and Biochemistry at the Georgia Institute of Technology.........

Posted by: Sarah      Permalink         Source

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