Source: http://news.feedzilla.com/en_us/stories/politics/top-stories/249388664?client_source=feed&format=rss
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Thursday, September 20, 2012
Using a laser to 'see' the smallest world: Powerful laser breathes new life into an old technology for studying atomic-level structures
ScienceDaily (Sep. 19, 2012) ? A multi-university team has employed a high-powered laser based at UC Santa Barbara to dramatically improve one of the tools scientists use to study the world at the atomic level. The team used their amped-up electron paramagnetic resonance (EPR) spectrometer to study the electron spin of free radicals and nitrogen atoms trapped inside a diamond.
The improvement will pull back the veil that shrouds the molecular world, allowing scientists to study tiny molecules at a high resolution.
The team, which includes researchers from UCSB, University of Southern California (USC), and Florida State University, published its findings this week in Nature.
"We developed the world's first free-electron laser-powered EPR spectrometer," said Susumu Takahashi, assistant professor of chemistry at the USC Dornsife College of Letters, Arts and Sciences, and lead author of the Nature paper. "This ultra high-frequency, high-power EPR system gives us extremely good time resolution. For example, it enables us to film biological molecules in motion."
By using a high-powered laser, the researchers were able to significantly enhance EPR spectroscopy, which uses electromagnetic radiation and magnetic fields to excite electrons. These excited electrons emit electromagnetic radiation that reveals details about the structure of the targeted molecules.
EPR spectroscopy has existed for decades. Its limiting factor is the electromagnetic radiation source used to excite the electrons -- it becomes more powerful at high magnetic fields and frequencies, and, when targeted, electrons are excited with pulses of power as opposed to continuous waves.
Until now, scientists performed pulsed EPR spectroscopy with a few tens of GHz of electromagnetic radiation. Using UCSB's free electron laser (FEL), which emits a pulsed beam of electromagnetic radiation, the team was able to use 240 GHz of electromagnetic radiation to power an EPR spectrometer.
"Each electron can be thought of as a tiny magnet that senses the magnetic fields caused by atoms in its nano-neighborhood," said Mark Sherwin, professor of physics and director of the Institute for Terahertz Science and Technology at UCSB. "With FEL-powered EPR, we have shattered the electromagnetic bottleneck that EPR has faced, enabling electrons to report on faster motions occurring over longer distances than ever before. We look forward to breakthrough science that will lay foundations for discoveries like new drugs and more efficient plastic solar cells."
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The above story is reprinted from materials provided by University of California - Santa Barbara.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- S. Takahashi, L.-C. Brunel, D. T. Edwards, J. van Tol, G. Ramian, S. Han, M. S. Sherwin. Pulsed electron paramagnetic resonance spectroscopy powered by a free-electron laser. Nature, 2012; 489 (7416): 409 DOI: 10.1038/nature11437
Note: If no author is given, the source is cited instead.
Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.
Source: http://feeds.sciencedaily.com/~r/sciencedaily/most_popular/~3/GcDQ_Z41sck/120919135415.htm
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Wednesday, September 19, 2012
Thermoelectric material is the best at converting heat waste to electricity
ScienceDaily (Sep. 19, 2012) ? Northwestern University scientists have developed a thermoelectric material that is the best in the world at converting waste heat to electricity. This is very good news once you realize nearly two-thirds of energy input is lost as waste heat.
The material could signify a paradigm shift. The inefficiency of current thermoelectric materials has limited their commercial use. Now, with a very environmentally stable material that is expected to convert 15 to 20 percent of waste heat to useful electricity, thermoelectrics could see more widespread adoption by industry.
Possible areas of application include the automobile industry (much of gasoline's potential energy goes out a vehicle's tailpipe), heavy manufacturing industries (such as glass and brick making, refineries, coal- and gas-fired power plants) and places were large combustion engines operate continuously (such as in large ships and tankers).
Waste heat temperatures in these areas can range from 400 to 600 degrees Celsius (750 to 1,100 degrees Fahrenheit), the sweet spot for thermoelectrics use.
The new material, based on the common semiconductor lead telluride, is the most efficient thermoelectric material known. It exhibits a thermoelectric figure of merit (so-called "ZT") of 2.2, the highest reported to date. Chemists, physicists, material scientists and mechanical engineers at Northwestern and Michigan State University collaborated to develop the material.
The study will be published Sept. 20 by the journal Nature.
"Our system is the top-performing thermoelectric system at any temperature," said Mercouri G. Kanatzidis, who led the research and is a senior author of the paper. "The material can convert heat to electricity at the highest possible efficiency. At this level, there are realistic prospects for recovering high-temperature waste heat and turning it into useful energy."
Kanatzidis is Charles E. and Emma H. Morrison Professor of Chemistry in Northwestern's Weinberg College of Arts and Sciences. He also holds a joint appointment at Argonne National Laboratory.
"People often ask, what is the energy solution?" said Vinayak P. Dravid, one of Kanatzidis' close collaborators. "But there is no unique solution -- it's going to be a distributed solution. Thermoelectrics is not the answer to all our energy problems, but it is an important part of the equation."
Dravid is the Abraham Harris Professor of Materials Science and Engineering at the McCormick School of Engineering and Applied Science and a senior author of the paper.
Other members of the team and authors of the Nature paper include Kanishka Biswas, a postdoctoral fellow in Kanatzidis' group; Jiaqing He, a postdoctoral member in Dravid's group; David N. Seidman, Walter P. Murphy Professor of Materials Science and Engineering at Northwestern; and Timothy P. Hogan, professor of electrical and computer engineering, at Michigan State University.
Even before the Northwestern record-setting material, thermoelectric materials were starting to get better and being tested in more applications. The Mars rover Curiosity is powered by lead telluride thermoelectrics (although it's system has a ZT of only 1, making it half as efficient as Northwestern's system), and BMW is testing thermoelectrics in its cars by harvesting heat from the exhaust system.
"Now, having a material with a ZT greater than two, we are allowed to really think big, to think outside the box," Dravid said. "This is an intellectual breakthrough."
"Improving the ZT never stops -- the higher the ZT, the better," Kanatzidis said. "We would like to design even better materials and reach 2.5 or 3. We continue to have new ideas and are working to better understand the material we have."
The efficiency of waste heat conversion in thermoelectrics is governed by its figure of merit, or ZT. This number represents a ratio of electrical conductivity and thermoelectric power in the numerator (which need to be high) and thermal conductivity in the denominator (which needs to be low).
"It is hard to increase one without compromising the other," Dravid said. These contradictory requirements stalled the progress towards a higher ZT for many years, where it was stagnant at a nominal value of 1.
Kanatzidis and Dravid have pushed the ZT higher and higher in recent years by introducing nanostructures in bulk thermoelectrics. In January 2011, they published a report in Nature Chemistry of a thermoelectric material with a ZT of 1.7 at 800 degrees Kelvin. This was the first example of using nanostructures (nanocrystals of rock-salt structured strontium telluride) in lead telluride to reduce electron scattering and increase the energy conversion efficiency of the material.
The performance of the new material reported now in Nature is nearly 30 percent more efficient than its predecessor. The researchers achieved this by scattering a wider spectrum of phonons, across all wavelengths, which is important in reducing thermal conductivity.
"Every time a phonon is scattered the thermal conductivity gets lower, which is what we want for increased efficiency," Kanatzidis said.
A phonon is a quantum of vibrational energy, and each has a different wavelength. When heat flows through a material, a spectrum of phonons needs to be scattered at different wavelengths (short, intermediate and long).
In this work, the researchers show that all length scales can be optimized for maximum phonon scattering with minor change in electrical conductivity. "We combined three techniques to scatter short, medium and long wavelengths all together in one material, and they all work simultaneously," Kanatzidis said. "We are the first to scatter all three at once and at the widest spectrum known. We call this a panoscopic approach that goes beyond nanostructuring."
"It's a very elegant design," Dravid said.
In particular, the researchers improved the long-wavelength scattering of phonons by controlling and tailoring the mesoscale architecture of the nanostructured thermoelectric materials. This resulted in the world record of a ZT of 2.2.
The successful approach of integrated all-length-scale scattering of phonons is applicable to all bulk thermoelectric materials, the researchers said.
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The above story is reprinted from materials provided by Northwestern University, via EurekAlert!, a service of AAAS.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- Kanishka Biswas, Jiaqing He, Ivan D. Blum, Chun-I Wu, Timothy P. Hogan, David N. Seidman, Vinayak P. Dravid, Mercouri G. Kanatzidis. High-performance bulk thermoelectrics with all-scale hierarchical architectures. Nature, 2012; 489 (7416): 414 DOI: 10.1038/nature11439
Note: If no author is given, the source is cited instead.
Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.
Source: http://feeds.sciencedaily.com/~r/sciencedaily/most_popular/~3/UXD0Myrzkno/120919135310.htm
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US futures rise with more positive housing news
FILE - In this Sept. 12, 2012 file photo, Michael O'Connor, right, of Getco Securities and a fellow trader work on the floor of the New York Stock Exchange in New York. Futures are edging higher Wednesday, Sept. 19, ahead of a pair of reports regarding the U.S. housing market that are expected to provide more hope for the beleaguered industry. (AP Photo/Henny Ray Abrams, File)
FILE - In this Sept. 12, 2012 file photo, Michael O'Connor, right, of Getco Securities and a fellow trader work on the floor of the New York Stock Exchange in New York. Futures are edging higher Wednesday, Sept. 19, ahead of a pair of reports regarding the U.S. housing market that are expected to provide more hope for the beleaguered industry. (AP Photo/Henny Ray Abrams, File)
NEW YORK (AP) ? Futures edged higher Wednesday with new data providing hope to beleaguered homeowners and the housing industry as well.
Construction of new homes and apartments rose 2.3 percent in August to a seasonally adjusted annual rate of 750,000, the Commerce Department reported, driven by the fastest pace of single-family home construction in more than two years.
Dow Jones industrial futures rose 19 points to 13,518. The broader S&P futures added 1.9 points to 1,454.80. Nasdaq futures tacked on 4.5 points to 2,854.50.
Later Wednesday, the National Association of Realtors will report on existing home sales. Economists are looking for more promising news there as well.
Sales of existing homes last month are expected to have risen by 1.8 percent to a seasonally adjusted annual rate of 4.55 million units, according to a survey by FactSet. The report will be released at 10 a.m. Eastern time.
Overseas, Japan's benchmark Nikkei 225 index hit a four-month high after the nation's central bank followed the U.S. Federal Reserve by broadening its massive asset purchasing plan, boosting funding to 55 trillion yen ($700 billion) from 45 trillion yen.
However, the bid by Tokyo to dampen the strong yen in order to better compete internationally did little for markets overseas.
In Europe, the FTSE 100 index of leading British shares was flat at 5,871 while Germany's DAX was down 0.1 percent at 7,342. The CAC-40 in France was also 0.1 percent lower at 3,508.
After the U.S Fed announced that it would spend $40 billion a month on mortgage-backed securities, markets from the U.S. to Asia to Europe skyrocketed.
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Tuesday, September 18, 2012
Skilled hunters 300,000 years ago
ScienceDaily (Sep. 17, 2012) ? Finds from early stone age site in north-central Germany show that human ingenuity is nothing new -- and was probably shared by now-extinct species of humans.
Archeologists from the University of T?bingen have found eight extremely well-preserved spears -- an astonishing 300,000 years old, making them the oldest known weapons anywhere. The spears and other artifacts as well as animal remains found at the site demonstrate that their users were highly skilled craftsmen and hunters, well adapted to their environment -- with a capacity for abstract thought and complex planning comparable to our own. It is likely that they were members of the species Homo heidelbergensis, although no human remains have yet been found at the site.
The project is headed by Prof. Nicholas Conard and the excavations are supervised by Dr. Jordi Serangeli, both from the University of T?bingen's Institute of Prehistory, which has been supporting the local authority's excavation in an open-cast brown coal mine in Sch?ningen since 2008. They are applying skills from several disciplines at this uniquely well-preserved site find out more about how humans lived in the environment of 300,000 years ago.
The bones of large mammals -- elephants, rhinoceroses, horses and lions -- as well as the remains of amphibians, reptiles, shells and even beetles have been preserved in the brown coal. Pines, firs, and black alder trees are preserved complete with pine cones, as have the leaves, pollen and seeds of surrounding flora.
Until the mining started 30 years ago, these finds were below the water table. The archeologists say they are now carrying out "underwater archaeology without the water." Work continues almost all year round, and every day there is something new to document and recover.
Some of the most important finds of the past three years have been remains of a water buffalo in the context of human habitation, an almost completely preserved aurochs (one of the oldest in central Europe), and several concentrations of stone artifacts, bones and wood. They allow the scientists to examine an entire landscape instead of just one site. That makes Sch?ningen an exciting location and global reference point not just for archaeology, but also for quaternary ecology and climate research. A research center and museum, the "Pal?on," is to be opened in 2013 to to provide information to the public about the work going on in Sch?ningen.
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Monday, September 17, 2012
Calif. illegal immigrants ask for school records
LOS ANGELES (AP) ? Thousands of illegal immigrants have inundated the nation's second-largest school district with requests for copies of records that might qualify them for the Obama administration's Deferred Action for Childhood Arrivals program, the district said Monday.
Under the program, people who are 30 or younger will be allowed to stay in the United States and work for up to two years if they prove they've lived in this country continuously since June 2007.
Applications can be renewed every two years.
An estimated 200,000 current and former students in the Los Angeles Unified School District might be eligible for the federal program, said Lydia Ramos, a special assistant to Superintendent John Deasy.
"We looked at the birth years that this program covers and there were about 200,000 students that listed another country of origin," Ramos said. "We have probably the highest number of students who would be eligible for this."
The Board of Education last week ordered that all current requests be handled within 35 days and future ones within seven days.
"I feel like doors are opening up for me," said 17-year-old Bell High School senior Saul Berrera, who was 10 when his mother brought him to the United States from El Salvador.
The school district already had a backlog of at least 2,300 requests for transcripts or diplomas before Aug. 15, the first day applicants for the Obama program could submit forms to the federal government, the Los Angeles Times (lat.ms/QTKDF8) reported.
"We are being inundated," Bell High School Principal Rafael Balderas said, adding his school was two weeks behind in providing documents. The school received about 200 requests for transcripts last year, but that total had been exceeded by July.
District officials notified schools on Friday that applicants can make requests online or fill out forms at schools for forwarding to the district's central office.
"We're doing this to relieve individual school sites from having to complete these when they already have reduced resources," Ramos said.
Records will be provided for free or at nominal cost. The federal government charges applicants $465 for each deferred action request.
Officials say there's a sense of urgency among applicants who worry about their window closing should Obama fail to win re-election in November.
"There are political considerations for some families," Ramos said.
The financially strapped school district expects to spend at least $200,000 in staff costs as well as an undetermined amount of overtime for employees who have worked to improve the records request system.
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Online: http://home.lausd.net
___
Information from: Los Angeles Times, http://www.latimes.com
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O'Malley makes early stop as 2016 prospect
INDIANOLA, Iowa (AP) ? Maryland Gov. Martin O'Malley, a 2016 presidential prospect, began forging an early ? and therefore tricky ? path into presidential proving ground Iowa on Sunday.
Appearing at Iowa Sen. Tom Harkin's annual steak fry, O'Malley dismissed the awkwardness that comes with trying to make a good first impression on Democratic activists in the leadoff caucus state, even as fewer than 60 days remained in Democratic President Barack Obama's re-election campaign.
"That's not what I'm doing here. I'm here because my friend Sen. Harkin asked me to come," the Democrat told reporters before speaking to hundreds of Iowa Democratic activists.
O'Malley was the keynote speaker at the Iowa Democrat's annual fundraiser, owning an important and well-worn national stage for White House aspirants while also rallying support for Obama's re-election in swing state Iowa.
"Let us return to the urgent work of creating more jobs, more security, more opportunity and a better future for our children," O'Malley said in closing his 20-minute speech to several hundred Democrats at a county fairgrounds south of Des Moines. "And let us together, Iowa, move forward and not back by re-electing Barack Obama president of the United States."
Vice President Joe Biden will be in Burlington, in the southeastern part of Iowa, to make that same argument Monday. Republican vice presidential candidate Paul Ryan will offer a rebuttal Monday in the state capital, Des Moines.
Jim and Kathy Young, Democrats from Solon in eastern Iowa, said O'Malley sounded like a presidential candidate.
"He sounds like a rising star," said Kathy Young. "I think we'll be hearing from him again."
O'Malley, who is chairman of the Democratic Governors Association, said he was in Iowa to "help the people of Iowa elect a new Democratic governor in 2014." Republican Gov. Terry Branstad has not yet said whether he plans to seek re-election in two years.
Yet, O'Malley also introduced himself to Iowa's Democratic faithful by telling his family story, including his father's World War II military service, and his policy profile, such as endorsing the referendum on the ballot in Maryland this November to legalize gay marriage.
O'Malley already had made some influential friends. Signs that read "Iowa AFSCME, Governor O'Malley" adorned the stage at the fairgrounds.
O'Malley is popular with AFSCME ? the American Federation of State, County and Municipal Employees ? in Maryland, Iowa Democratic officials said, and had reached out to Iowa's public employees union.
O'Malley formed a political action committee this year and last week hired a former Obama campaign aide to advise him.
He met with the Iowa delegation to the Democratic National Convention in Charlotte, N.C., last month. And Sunday he heaped praise on Harkin, a five-term senator and pillar among Iowa Democrats.
Other presidential prospects who have appeared at the Harkin event during its 35-year history include Obama in 2006 and John Edwards in 2005.
And while it's still more than four years until the 2016 election, O'Malley is not the first would-be presidential prospect to begin reaching out in Iowa before one election is over.
Republican Mitt Romney headlined an Iowa GOP dinner in October 2004, a month before George W. Bush was re-elected. Romney, now the GOP's presidential nominee, unsuccessfully sought the 2008 nomination.
Source: http://news.yahoo.com/omalley-makes-early-stop-2016-prospect-200557256--election.html
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