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Students will put 'chem-car' to national test


June 7, 2010

A team of ASU students will showcase their technological skills in a national competition organized by the American Institute of Chemical Engineers, one of the world’s leading professional engineering organizations.

They’ll take part in the National Chem-E-Car Competition during the institute’s annual student conference in Salt Lake City, Utah, Nov. 6 and 7. Download Full Image

The team earned its way to the national competition by finishing in third place overall this spring in the institute’s Rocky Mountain Region Chem-E-Car Competition at the University of New Mexico.

The contest requires teams to design and construct chemically powered shoebox-sized vehicles that produce a chemical reaction to start and stop the vehicles. Teams are told only hours before the start of competition about the distance their cars must travel and the amount of cargo that each vehicle will carry.

Representing ASU will be chemical engineering undergraduates Jacob Lenzi, Luis Moya, Tara Smith, Kyle Foster, Alison Davis, Brian Anderson, Andrew Chelsy, Mike Rosauri, and mechanical engineering undergraduate Mark Garrison.

At the regional event, they took first place for most creative vehicle design and first place in the project poster presentation part of the competition.

Engineering assistant professor Bryan Vogt, faculty adviser to the ASU student chapter of the American Institute of Chemical Engineers, explains that the team’s performance is an exceptional accomplishment.

Many successful teams work from previous models as a starting point for car design, Vogt says. The ASU team didn’t have a previously designed car from which to start, so “the car that qualified for nationals was built fully from scratch,” he says.

“Qualifying for the National Chem-E-Car Competition is very exciting for the entire team,” says second-year competitor Smith. “Our success in the regional competition validated the tremendous amount of hard work we put in over the spring semester. The car consumed about eight hours a week of my life for the entire school year, so it feels really good that it has performed so well,” says Smith.

The team hand built the car in a mechanical engineering machine shop, with assistance from Fred Pena, a research lab manager in the School for Engineering of Matter, Transport and Energy, a part of ASU’s Ira A. Fulton Schools of Engineering.

Students learned to advanced equipment and about designing problem-solving methods. They constructed three “chem-cars” before they were satisfied they had a vehicle ready for competition.

“It’s been a lot of work, but the hands- on experience has been priceless,” says Smith. “It really seals in our memories what we have been learning in class, and gives us a creative outlet.”  

The team’s vehicle runs through the use of thermal junctions that produce electricity by creating a heat transfer through the junctions. The team created a 110 Celsius temperature difference by using dry ice in an ethanol bath on one side, and the dissociation of sulfuric acid in water on the other.

“The Chem-E-Car’s success is proof of the value of the education I received in engineering at ASU. I’ve learned a lot by building the car,” Smith says.

“These types of projects provide important opportunities for hands-on experiences outside the classroom,” says Kyle Squires, director of the School for Engineering of Matter, Transport and Energy. “That this team has done so well without starting from a previously designed vehicle speaks highly of their hard work and dedication. We’re looking forward to seeing them compete in the finals.”

The team received support from the USG Corp., the Ira A. Fulton Schools of Engineering, and several local companies, including Schlumberger, Abbie Gregg Inc., Air Products and Salt River Project.

Written by Jessica Graham

Joe Kullman

Science writer, Ira A. Fulton Schools of Engineering

480-965-8122

Multidisciplinary capstone brings light - and more - to developing countries


May 17, 2010

Students in the new GlobalResolve social entrepreneurship capstone course are completing initial business plans in preparation for a two-week trip to Ghana in May to study local resources and needs.

The entrepreneurs – students in the fields of engineering, business, design and more – are making plans for the production and sale of inventions, including an award-winning generator and clean-burning stoves. Download Full Image

“We’re shooting for affordability – we want to keep the price for our product under $20,” said Raphael Hyde, the leader of a project team that is making plans to manufacture and market the generator known as Aura (Twig) Light. “The challenge will be finding ways to produce enough units to meet local demand.”

“In the next year, through this team, we hope to bring some light into developing areas of Ghana.”

Hyde and his team – Nisha Patel, Lisa Regets and Michael Pugliese – recently won ASU’s top Challenges Innovator award for $5,000 in venture funding and have applied for the Edson Venture Creator grant, which offers an opportunity for student entrepreneurs to win up to $20,000.

“I’ve never done anything like this before,” Hyde said enthusiastically. “It’s a great learning opportunity. Among everything I’ve seen and everywhere I’ve traveled, this program offers the greatest opportunity for growth.”

Hyde said that he has a passion for innovative energy solutions, with experience working for one of Asia’s biggest lighting companies. He hopes to use this experience to start another company and continue developing energy solutions after his graduation.

“There’s so much happening in the world,” said Hyde, now in his third year in ASU’s industrial design and business program. “If you bring together students who are the best in their field, who care, and give us a chance, we can make a huge impact.”

To follow the group’s trip to Ghana, Africa, visit http://globalresolve.asu.edu/" target="_blank">http://globalresolve.asu.edu/ and click on the blog, starting May 17. You may also follow them on Linked In. Search for GlobalResolve under the “Groups” tab to get connected and to learn more about the trip.


Written by Kari Stallcop

Media contact:
Chris Lambrakis
(480)727-1173

ASU In the News

ASU prof joins national radio show biofuels talk


<p>Science Friday, the popular National Public Radio show, recently explored research on biofuels and the promise they hold as a viable additional source for energy and fuels.</p><p>Among experts interviewed by Science Friday host Ira Flatow was leading biofuels researcher and Arizona State University professor Bruce Rittman.</p><p>Rittmann directs the Center for Environmental Biotechnology in ASU’s Biodesign Center and teaches in the School of Sustainable Engineering and the Built Environment, a part of ASU’s Ira A. Fulton Schools of Engineering.</p><p>He talks to Science Friday about the potential for using algae and cyanobacteria as sources for microbial fuel cells.</p><p>Click the link below. Look for the activation bar for an audio recording of program near the top left side of the web page.</p>

Article Source: Science Friday - National Public Radio
Joe Kullman

Science writer, Ira A. Fulton Schools of Engineering

480-965-8122

ASU partners with City of Phoenix on $25M project


April 21, 2010

The City of Phoenix was awarded a $25 million federal grant from the U.S. Department of Energy and the American Recovery and Reinvestment Act (ARRA) to launch, in partnership with Arizona State University and Arizona Public Service, “Energize Phoenix” – a project that will save energy, create jobs and transform neighborhoods.

The grant will be used as seed funding to establish a fiscally viable, permanent program that will eventually be expanded throughout the city. Locally, the funds will be leveraged by at least $190 million of additional funding from a combination of banks, local businesses and public partners. Download Full Image

Looking to the future of the Phoenix Light Rail Corridor, Arizona’s most promising emerging economic opportunity region, Energize Phoenix has been launched by the City of Phoenix, the Global Institute of Sustainability at ASU and Arizona Public Service Company (APS). It will transform the corridor’s neighborhoods and commercial districts along a 10-mile stretch of the light rail line into a Green Rail Corridor that will become a model of energy efficiency and sustainability.

The corridor spans diverse neighborhoods of communities, commercial businesses, public institutions and offices. Much of the area, however, consists of aging homes and commercial buildings and a large percentage of households are below the poverty line.

Through an innovative strategy supported by a mix of public and private funding, Energize Phoenix is designed to create 1,900 to 2,700 new jobs, most of which will be “green jobs.” These will include jobs for energy auditors, efficient-equipment installers and residential energy consultants to install electricity feedback devices that show residents how much energy they are using, and simple steps to reduce their energy use. Also included are traditional trade jobs.

This is the first major project to be implemented as part of a larger sustainability strategy for the city called “Green Phoenix,” which was designed in collaboration with ASU’s Global Institute of Sustainability.

In addition to creating thousands of local jobs, building the Green Rail Corridor will establish novel financial mechanisms to spur energy efficient investments and cut monthly energy costs for households and businesses. At the same time, it will reduce harmful carbon emissions and improve residential and commercial buildings through energy efficient upgrades and weatherization. Most important, the project will instill a sense of pride in the community and create a model of energy efficiency and long-term sustainability adaptable to major cities elsewhere.

These resources will be used to achieve specific goals – shrink home energy consumption by 30 percent, reduce commercial energy use by 18 percent, eliminate carbon emissions by 50,000 metric tons per year, retrofit 3,500 homes and 30 million square feet of office and industrial space for greater energy efficiency, and advance energy efficiency as the option of choice for the local community.

Strategic partnerships among the three primary partners will link city management and operations with university research and utility energy delivery and measurement to achieve results.

“The City of Phoenix has a history of cooperation and success in partnering with ASU and APS,” said Phoenix Mayor Phil Gordon. “These strong relationships have engendered trust and cooperation among team members, so we can rely on each other to fulfill our commitments. This project will effectively move Phoenix closer to its goal of carbon-neutrality and becoming one of the most sustainable cities in the country.”

“ASU’s strengths in sustainability and renewable energy span the gamut from cutting-edge theoretical, such as our research to create jet fuel from algae, to on-the-ground transformative projects, such as Energize Phoenix,” said ASU President Michael M. Crow. “It is another example of the great public benefit that is derived from the partnership of ASU with the City of Phoenix.”

Rob Melnick, executive dean of ASU’s Global Institute for Sustainability and the university’s leader of the project, added:

“We are applying a unique strategy for achieving energy efficiency that combines market-based incentives, new technology and consumer education. This project will provide direct, real time feedback to consumers about their energy consumption, offer access to financing for commercial properties and energy service companies performing energy retrofits, and collect timely data on progress so we can monitor and improve our approach almost instantly. We intend to make energy efficiency a social norm for this community and demonstrate this as a model others can use around the world.”

The city will oversee management of weatherization retrofits, investment capital and worker training. Workers will be trained for “green jobs,” such as energy auditing and solar energy installation, through community colleges serving the Green Rail Corridor.

This project does not rely on regulatory mechanisms or prolonged federal investments for success. As the sole electricity provider to the Green Rail Corridor, APS will play an essential role in providing energy consumption data to the project, using energy-efficiency incentives to spur private investment, deploying a smart-metering system for energy monitoring and educating residents about how to maximize their energy savings.

In addition to being involved in applied problem-solving projects such as this, ASU conducts a wide range of renewable energy research that advances new sustainable technologies. These projects include: 
 
A Department of Energy funded Energy Frontier Research Center devoted to advanced research on solar energy conversion; two ARPA-E projects (also DOE) – one for work on a new class of high-performance metal-air batteries and the other on photosynthetic bacteria to produce automotive fuels; development of cyanobacteria and algae as sources of environmentally friendly fuel produced by solar energy conversion; a revolutionary new environmental biotechnology called the microbial fuel cell that turns the treatment of organic wastes into a source of electricity; and development of new methods for efficiently converting water into hydrogen.

ASU also has several hands-on projects, including work on helping communities adopt renewable energy practices; a Solar Power Laboratory that explores the use of nanotechnology in next generation of solar cells; a center – one of three in the world – certified for photovoltaic module performance qualification, certification and reliability testing; campus solar installations that provide 2 MW of power (total generating capacity will be more than 10 MW by September 2010); and engineering researchers who are working to develop technology to transform the centralized power grid into a “smart grid” that can store and distribute energy produced from wind farms, solar panels, fuel cells and other renewable energy sources.

About ASU’s Global Institute of Sustainability

The Global Institute of Sustainability is the hub of ASU’s sustainability initiatives. The Institute advances research, education and business practices for an urbanizing world. Its School of Sustainability, the first of its kind in the US, offers transdisciplinary degree programs that advance practical solutions to environmental, economic, and social challenges. For more information visit the Global Institute of Sustainability at http://sustainability.asu.edu

Sources:http://sustainability.asu.edu">http://sustainability.asu.edu. <... />Rob Melnick, ASU Global Institute of Sustainability, (480) 965-2975
Matthew Fraser, ASU School of Sustainability, (480) 965-3489

Media contacts:
Skip Derra, (480) 965-4823; skip.derra">mailto:skip.derra@asu.edu">skip.derra@asu.edu

Handbook serves as resource for science policy decision-makers


April 12, 2010

In 2010, the U.S. government will spend more than $150 billion on research and development. What gets done with that enormous sum has important implications for the wide variety of problems facing our society.  

Decisions on challenges such as national defense, environmental change, rapid urbanization and public health rely on scientific knowledge to inform them. Given the complexity and the significance of such challenges, how can science funders effectively orient a vast research enterprise to make real progress toward desired social goals? Download Full Image

The Science Policy Assessment and Research on Climate (SPARC) project announces the release of its publication "Usable Science: A Handbook for Science Policy Decision Makers." It is intended to be a resource for anyone involved in the process of designing, directing or implementing research – those who decide what research gets done and whose needs the research is intended to serve, including professionals in federal agencies, congressional staffers, scientists managing a lab or sitting on a panel at the National Research Council, or managers at a foundation with a science focus.

The handbook addresses the challenge of producing usable science, defined as science that meets the changing needs of decision-makers. SPARC presents concrete examples from diverse areas, from earthquake research to materials science, and offers specific recommendations for organizations and individuals interested in becoming more effective at producing usable science. These include understanding and connecting with potential users of science in setting the course of research policies, developing creative incentives and evaluation metrics, and recognizing innovative leadership.

The handbook will be released at a workshop in Washington, D.C., April 12, featuring the former presidential science adviser, John Marburger, and researchers from SPARC. SPARC is a joint project of the University of Colorado's Center for Science and Policy Technology Research and ASU's Consortium">http://www.cspo.org/">Consortium for Science, Policy and Outcomes, and is funded by the National Science Foundation. SPARC conducts research and assessment, outreach and education aimed at helping climate science policies better support climate-related decision making in the face of fundamental and often irreducible uncertainties.

For a hardcopy of the handbook, please e-mail Ami Nacu-Schmidt, ami">mailto:ami@cires.colorado.edu">ami@cires.colorado.edu. It also is available online at http://sciencepolicy.colorado.edu/sparc/outreach/sparc_handbook">http://sciencepolicy.colorado.edu/sparc/outreach/sparc_handbook">http://..., and can be downloaded at http://sciencepolicy.colorado.edu/sparc/outreach/sparc_handbook/brochure.pdf.

For">http://sciencepolicy.colorado.edu/sparc/outreach/sparc_handbook/brochure... more information about SPARC, visit">http://sciencepolicy.colorado.edu/sparc/">visit http://sciencepolicy.colorado.edu/sparc/.

Research opens door to clean biofuel production


March 31, 2010

Using genetic sleight of hand, Xinyao Liu, an ASU researcher, and Roy Curtiss, professor, at ASU's Biodesign Institute have coaxed photosynthetic microbes to secrete oil – bypassing energy and cost barriers that have hampered green biofuel production.

Their results appear in this week's advanced online issue of the Proceedings of the National Academy of Sciences or PNAS. Download Full Image

The challenges of developing a renewable biofuel source that is competitive with the current scalability and low-cost of petroleum have been daunting.

"The real costs involved in any biofuel production are harvesting the fuel precursors and turning them into fuel," said Roy Curtiss, director of the Biodesign Institute's Center for Infectious Diseases and Vaccinology and professor in the School of Life Sciences. "By releasing their precious cargo outside the cell, we have optimized bacterial metabolic engineering to develop a truly green route to biofuel production."

Photosynthetic microbes called cyanobacteria offer attractive advantages over the use of plants like corn or switchgrass, producing many times the energy yield with energy input from the sun and without the necessity of taking arable cropland out of production.

Lead author Xinyao Liu and Curtiss applied their expertise in the development of bacterial-based vaccines to genetically optimize cyanobacteria for biofuel production. Last year, they were able to modify these microbes, priming them to self-destruct and release their lipid contents. In the group's lastest effort however, the energy-rich fatty acids were extracted without killing the cells in the process.

"In China, we have a saying," Liu said. "We don't kill the hen to get the eggs."

Rather than destroying the cyanobacteria, the group has ingeniously reengineered their genetics, producing mutant strains that continuously secrete fatty acids through their cell walls. The cyanobacteria, essentially, act like tiny biofuel production facilities.

Liu realized that if cyanobacteria could be cajoled into overproducing fatty acids, their accumulation within the cells would eventually cause these fatty acids to leak out through the cell membrane, through the process of diffusion. To accomplish this, Liu introduced a specific enzyme, known as thioesterase, into cyanobacteria.

The enzyme is able to uncouple fatty acids from complex carrier proteins, freeing them within the cell where they accumulate, until the cell secretes them.

"I use genes that can steal fatty acids from the lipid synthesis pathway," Liu said and noted that thioesterase acts to efficiently clip the bonds associating the fatty acids with more complex molecules. This use of modified thioesterases to cause secretion of fatty acids was first described for Escherichia coli by John Cronan of the University of Illinois more than a decade ago.

A second series of modifications enhances the secretion process, by genetically deleting or modifying two key layers of the cellular envelope – known as the S and peptidoglycan layers – allowing fatty acids to more easily escape outside the cell, where their low water solubility causes them to precipitate out of solution, forming a whitish residue on the surface. Study results show a threefold increase in fatty acid yield, after genetic modification of the two membrane layers.

To improve the fatty acid production even further, the group added genes to cause overproduction of fatty acid precursors and removed some cellular pathways that were non-essential to the survival of cyanobacteria. Such modifications ensure that the microbe's resources are devoted to basic survival and lipid production.

Liu said that the current research has moved along at a lightening clip, with only about six months passing from the initial work, through production of the first strains – a fact he attributes to the formidable expertise in the area of microbial genetic manipulation, assembled at the Biodesign Institute.

"I don't think any group would have the capacity to do this as fast," he said.

Professor Roy Curtiss agrees and noted that "the seminal advance has been to combine a number of genetic modifications and enzyme activities previously described in other bacteria and in plants in the engineered cyanobacteria strains along with the introduction of newly discovered modifications to increase production and secretion of fatty acids. The results to date are encouraging and we are confident of making further improvements to achieve enhanced productivity in strains currently under construction and development. In addition, optimizing growth conditions associated with scale-up will also improve productivity."

The team, which includes researchers Daniel Brune and Wim Vermaas, is optimistic that significantly higher fatty acid yields will be obtainable, as research continues.

The research opens the door to practical use of this promising source of clean energy.


Written by Richard Harth
Biodesign Institute Science Writer
richard.harth">mailto:richard.harth@asu.edu">richard.harth@asu.edu

Joe Caspermeyer

Manager (natural sciences), Media Relations & Strategic Communications

480-727-4858

Partnership to advance solar energy technology


March 30, 2010

Arizona State University and the University of Tokyo are joining forces to advance photovoltaics technology

Arizona State University has established a partnership with the University of Tokyo, Japan, aimed at strengthening research and educational endeavors at both institutions to advance solar energy technology.

The University of Tokyo is rated by the Global University Ranking organization and others as one the leading universities and research institutions in Asia, and it is the leading solar-energy research institution in Japan. Download Full Image

Its Research Center for Advanced Science and Technology recently was awarded almost $100 million over a seven-year period from the government of Japan for the Solar Quest program on advanced photovoltaic design, said Stephen Goodnick, director of the Arizona Initiative for Renewable Energy at ASU.

Photovoltaics is the field of semiconductor technology that involves converting sunlight into electrical power.

Goodnick also is a professor in the School of Electrical, Computer and Energy Engineering, a part of ASU’s Ira A. Fulton Schools of Engineering. At the invitation of the University of Tokyo, he and fellow ASU electrical and energy engineering professor Yong-Hang Zhang attended an international photovoltaics workshop last year in Japan. The idea for the partnership grew out of meetings Goodnick and Zhang had with Japanese colleagues during the conference.

Under the three-year partnership agreement, the two universities will collaborate on research projects, exchange educational information and materials, conduct joint lectures and symposia and exchange services of faculty members, research staff and students.

“It is our great pleasure to have concluded the partnership agreement with one of the most advanced research institutes in the United States in the field of renewable energy,” said professor Yoshiaki Nakano, leader of the Solar Quest program. “We believe this will have a significant impact on our research progress at Solar Quest.”

The universities’ partnership, along with cooperative efforts by the governments of the United States and Japan, will help both countries “achieve far better solutions to our common challenges of producing renewable energy and protecting our environment,” Nakano said.

At ASU, researchers with the Arizona Initiative for Renewable Energy, the Biodesign Institute and the Ira A. Fulton Schools of Engineering are involved in a wide range of efforts to make solar cell technology more efficient and affordable.

The partnership with the University of Tokyo “will greatly advance research in what is called third-generation photovoltaics, which seeks to make major improvements in the efficiency of solar electricity, leading to significant cost reductions,” Goodnick says.

One of the first joint efforts of the partnership will be the study of high-efficiency, multi-junction solar cells, using compound semiconductor materials to optimize the absorption of the full solar spectrum.

Zhang says this type of cell could be used for solar energy generation both in space and for terrestrial applications in what is termed “concentrating photovoltaics,” where sunlight is focused at up to 1,000 times its normal intensity onto such high-efficiency cells, reducing the cost of generating solar electricity.

This work is currently supported by the Science Foundation Arizona in partnership with Roger Angel at the University of Arizona.

A second project will involve joint research on intermediate-band solar cells to capture more photons from the solar spectrum, which will increase cell efficiency, Goodnick says.

Based on growing nanostructures such as quantum dots within the solar cell, this project will involve collaboration with Christiana Honsberg, director of the recently established Solar Power Laboratory at ASU.

For more information on the Arizona Initiative for Renewable Energy, see:
http://aire.asu.edu/index.shtml />
# # #

Ira A. Fulton Schools of Engineering:
http://engineering.asu.edu/ />The Ira A. Fulton Schools of Engineering at Arizona State University serve more than 4,000 undergraduates and 2,000 graduate students, providing skills and knowledge for shaping careers marked by innovation and societal impact. Ranked nationally in the top 10 percent among engineering schools rated by US News & World Report magazine, the school engages in use-inspired research in a multidisciplinary setting for the benefit of individuals, society and the environment. The school’s 200-plus faculty members teach and pursue research in areas of electrical, chemical, mechanical, aerospace, civil, environmental and sustainable engineering, as well as bioengineering, energy engineering, computer science and engineering, informatics, decision systems, and construction management. The schools of engineering also work in partnership with the School of Arts, Media and Engineering and the School of Earth and Space Exploration, and faculty work collaboratively with the Biodesign Institute at ASU, the School of Sustainability and the Global Institute of Sustainability.

# # #


SOURCE:
Stephen Goodnick,
stephen.goodnick@asu.edu
Director
Arizona Initiative for Renewable energy
(480) 965-9572

MEDIA CONTACT:
Joe Kullman, joe.kullman@asu.edu
(480) 965-8122 direct line
(480) 773-1364 mobile

Ira A. Fulton Schools of Engineering
Arizona State University
Tempe, Arizona  USA
http://engineering.asu.edu/ /> 


Joe Kullman

Science writer, Ira A. Fulton Schools of Engineering

480-965-8122

New alloys key to efficient energy and lighting


March 22, 2010

Nanowire advances promise improved light-emitting diodes and solar-energy generation

A recent advance by ASU researchers in developing nanowires could lead to more efficient photovoltaic cells for generating energy from sunlight, and to better light-emitting diodes (LEDs) that could replace less energy-efficient incandescent light bulbs. Download Full Image

Electrical engineers Cun-Zheng Ning and Alian Pan are working to improve quaternary alloy semiconductor nanowire materials.

Nanowires are tens of nanometers in diameter and tens of microns in length. Quaternary alloys are made of semiconductors with four elements, often made by alloying two or more compound semiconductors.

Semiconductors are the material basis for technologies such as solar cells, high-efficiency LEDs for lighting, and for visible and infrared detectors.

One of the most critical parameters of semiconductors that determine the feasibility for these technologies is the band gap. The band gap of a semiconductor determines, for example, if a given wavelength of sun light is absorbed or left unchanged by the semiconductor in a solar cell.

Band gap also determines what color of light an LED emits. To make solar cells more efficient, it’s necessary to increase the range of band gaps.

Ideally, the highest solar cell efficiency is achieved by having a wide range of band gaps that matches the entire solar spectrum, said Ning, a professor in the School of Electrical, Computer and Energy Engineering, a part of ASU’s Ira A. Fulton Schools of Engineering.

He said that in LED lighting applications, more available band gaps means more colors can be emitted, providing more flexibility in color engineering or color rendering of light.

For example, different proportions of red, green and blue colors would mix with different white colors. More flexibility would allow white color to be adjusted to suit various situations, or individual preferences.

Similarly, Ning said, detection of different colors requires semiconductors of different band gaps. The more band gaps that are available, the more information can be acquired about an object to be detected. Thus, all of these lighting applications can be improved by having semiconductors with a wide range of band gaps.

The researchers said the hurdle is that every manmade or naturally occurring semiconductor has only a specific band gap.

One standard way to broaden the range of band gaps is to alloy two or more semiconductors. By adjusting the relative proportion of two semiconductors in an alloy, it’s possible to develop new band gaps between those of the two semiconductors.

But accomplishing this requires a condition called lattice constant matching, which requires similar inter-atomic spaces between two semiconductors to be grown together.

“This is why we cannot grow alloys of arbitrary compositions to achieve arbitrary band gaps,” Ning said. “This lack of available band gaps is one of the reasons current solar cell efficiency is low, and why we do not have LED lighting colors that can be adjusted for various situations.”

In recent attempts to grow semiconductor nanowires with “almost” arbitrary band gaps, the research team led by Ning and Pan, an assistant research professor, have used a new approach to produce an extremely wide range of band gaps.

They alloyed two semiconductors, zinc sulfide (ZnS) and cadmium selenide (CdSe) to produce the quaternary semiconductor alloy ZnCdSSe, which produced continuously varying compositions of elements on a single substrate (a material on which a circuit is formed or fabricated).

Ning said this is the first time a quaternary semiconductor has been produced in the form of a nanowire or nanoparticle.

By controlling the spatial variation of various elements and the temperature of a substrate (called the dual-gradient method), the team produced light emissions that ranged from 350 to 720 nanometers on a single substrate only a few centimeters in size.

The color spread across the substrate can be controlled to a large degree, and Ning said he believes this dual-gradient method can be more generally applied to produce other alloy semiconductors or expand the band gap range of these alloys.

To explore the use of quaternary alloy materials for making photovoltaic cells more efficient, his team has developed a lateral multi-cell design combined with a dispersive concentrator.

The concept of dispersive concentration, or spectral split concentration, has been explored for decades. But the typical application uses a separate solar cell for each wavelength band.

With the new materials, Ning said he hopes to build a monolithic lateral super-cell that contains multiple subcells in parallel, each optimized for a given wavelength band. The multiple subcells can absorb the entire solar spectrum. Such solar cells will be able to achieve extremely high efficiency with low fabrication cost. The team is working on both the design and fabrication of such solar cells.

Similarly, the new quaternary alloy nanowires with large wavelength span can be explored for color-engineered light applications.

The researchers have demonstrated that color control through alloy composition control can be extended to two spatial dimensions, a step closer to color design for direct white light generation or for color displays.

The team’s research was initially supported by Science Foundation Arizona and by the U.S. Army Research Office.

For more information, see the research group’s Web site at http://nanophotonics.asu.edu.

Related">http://nanophotonics.asu.edu">http://nanophotonics.asu.edu.

Re... research by Ning and his colleagues has been reported in these articles:

• Pan, R. Liu, M. Sun and C.Z. Ning, Spatial Composition Grading of Quaternary ZnCdSSe Alloy Nanowires with Tunable Light Emission between 350 and 710 nm on a Single Substrate, ACS Nano, http://pubs.acs.org/doi/abs/10.1021/nn901699h

">http://pubs.acs.org/doi/abs/10.1021/nn901699h">http://pubs.acs.org/doi/a...• Pan, R. Liu, M. Sun and C.Z. Ning, Quaternary Alloy Semiconductor Nanobelts with Bandgap Spanning the Entire Visible Spectrum, J. Am. Chem. Soc, 131, 9502 (2009), DOI: 10.1021/ja904137m, http://pubs.acs.org/doi/abs/10.1021/ja904137m

">http://pubs.acs.org/doi/abs/10.1021/ja904137m">http://pubs.acs.org/doi/a...• C.Z. Ning, A. Pan, and R. Liu, Spatially composition-graded alloy semiconductor nanowires and wavelength specific lateral multi-junctions full-spectrum solar cells, Proceedings of 34th PVSC, IEEE, 001492(2009).

Joe Kullman

Science writer, Ira A. Fulton Schools of Engineering

480-965-8122

ASU In the News

Is more nuclear power in Arizona a good idea?


<p>With a rapidly growing need for more electricity, public support for nuclear power is rising. Some national and state government leaders are pushing for a renewed commitment to nuclear energy.</p><p>On a recent broadcast of the KAET-Channel 8 public affairs program Horizon, Keith Holbert, an associate professor in the School of Electrical, Computer and Energy Engineering, a part of ASU’s Ira A. Fulton Schools of Engineering, discussed the potential benefits and challenges of expanding the use of nuclear energy.</p><p>He was joined by Renz Jennings, a former member of the Arizona Corporation Commission, which regulates utility providers in the state.</p><p>Cost, waste containment , and the years it takes to bring a nuclear power plant online are among the hurdles&nbsp; to construction of more nuclear power plants, Holbert points out.</p><p>But he says the advantages outweigh the costs.&nbsp; The revival of interest in nuclear energy is positive because it’s a reliable source of energy without the carbon dioxide emissions that can contribute to climate change.</p><p>It won’t require a major technological leap to design and build new nuclear reactors. We can improve on reactors already operating in the United States, Europe and Asia, Holbert says.</p><p>See video of the program at the link below.</p>

Article Source: Horizon, KAET-Channel 8
Joe Kullman

Science writer, Ira A. Fulton Schools of Engineering

480-965-8122

Decision Theater offers balance to an off-kilter world


February 23, 2010

What we know as the “Earth system” was, until recently, composed of several large-scale natural processes all seeking a balance with each other. For example, atmospheric activity and carbon and phosphorus cycles tended toward stability with Earth ecosystems. In the last 100 years or so, however, many human activities have scaled up so dramatically they have begun to knock the old equilibriums off-kilter.

“Humans have, essentially, created a coupled human-natural system for our planet,” said George Basile, executive director of Arizona State University’s Decision Theater and a professor in the School of Sustainability. No one, however, completely understands the ramifications of this change. Download Full Image

Speaking at the American Association for the Advancement of Science (AAAS) annual meeting Feb. 20, Basile compared humanity’s rapid consumption and waste of natural resources to running a massive science experiment without safeguards or monitoring.

What is a major cause of humanity’s reckless behavior? We don’t know how to make good, sustainable decisions.

“Sustainability challenges are decision challenges,” Basile said. “Decision-makers today require clarity of issues and an array of possible responses far beyond the simple cause-and-effect models applied in the past.”

In his presentation, “Visualization in decision support for sustainability,” Basile discussed the primary obstacles to making good decisions: mind-bendingly complex systems, extreme large-scale processes, long-term causes and effects, and chronic uncertainty regarding catastrophic thresholds and the probability of disastrous interactions.

Using two case studies from Decision Theater’s experience — an effective response strategy for pandemic flu and water planning for climate change — Basile illustrated how a “systems approach” to decision-making can mitigate uncertainties and create robust solutions.

“We work with decision-makers to understand what success looks like from their perspective,” he said. “Then we layer in what success requires from a biophysical or socio-politico perspective – this is where experts add a lot. 

"Bringing these diverse perspectives together helps us create flexible steps forward that embrace both the best science and key policy realities. We then ‘exercise’ the most promising possibilities through visualizations and other strategies to help people see their decisions in an action-oriented way and find their optimal short-term and long-term solutions.”

The key, Basile said, is to focus on the decision-makers first.

“Today’s emerging sustainability challenges are complex and new to us all,” he said. “Meeting them is both increasingly critical and increasingly difficult.” By focusing on the needs of decision-makers first, then applying a transdisciplinary framework and working collaboratively with experts and current research, the best decisions can be identified and then adapted through an iteractive process that links informed planning to sustainable actions.


Bio

George Basile leads a multidisciplinary team at Arizona State University’s Decision Theater, which is focused on sustainability and public policy, and he also serves as a faculty member in ASU’s School of Sustainability. Basile started out on a traditional academic career path with a bachelor of science degree in physics from UC Irvine, a doctorate in biophysics from UC Berkeley, and a postdoctorate degree at Lawrence Berkeley Laboratory. He has held teaching positions at Berkeley and Stanford, and helped develop “Green MBA” programs in the United States and Sweden. He currently serves on the boards of nonprofit organizations and new ventures, and advises Fortune 500 clients on sustainable business practices, and integrated operational and marketing strategies. He served as the R&D head of The Natural Step, an accelerator of global sustainability, and co-founded Thrive Unlimited. Basile is widely published and sought after as a speaker focusing on creating strategic alignment between business drivers and emerging market needs.

About ASU's Decision Theater and Global Institute of Sustainability
Decision Theater, a unit of the Global Institute of Sustainability at Arizona State University, is a decision-lab that provides organizations, agencies, and governments with the tools to address emerging sustainability challenges using visualization, informatics, and analytics (visit www.decisiontheater.org). The Global Institute of Sustainability is the hub of ASU's sustainability initiatives. The Institute advances research, education, and business practices for an urbanizing world. Its School of Sustainability, the first of its kind in the US, offers transdisciplinary degree programs that advance practical solutions to environmental, economic, and social challenges (visit http://sustainability.asu.edu">http://sustainability.asu.edu">http://sustainability.asu.edu).


Media Contact:
Karen Leland, karen.leland">mailto:karen.leland@asu.edu">karen.leland@asu.edu
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