Shift to green energy sources could mean crunch in supply of scarce metals

Engineerblogger
March 8, 2012

A large-scale shift from coal-fired electric power plants and gasoline-fueled cars to wind turbines and electric vehicles could increase demand for two already-scarce metals — available almost exclusively in China — by 600-2,600 percent over the next 25 years, a new study has concluded. Published in the ACS journal Environmental Science & Technology, it points out that production of the two metals has been increasing by only a few percentage points per year.

Randolph E. Kirchain, Ph.D., and colleagues explain that there has been long-standing concern about a secure supply of the so-called rare earth elements, 17 elements adjacent on the periodic table of elements. These metals are used to make airplane components and lasers for medical imaging. Two of the rare earths, dysprosium and neodymium, are critical for current technologies for manufacturing wind turbines that generate electricity and electric vehicles. Those green technologies, Kirchain notes, would be essential in carrying out a proposed stabilization in atmospheric levels of carbon dioxide, the main greenhouse gas, at 450 parts per million. Kirchain’s team analyzed the supply of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium and yttrium under various scenarios.

They projected the demand for these 10 rare earth elements through 2035. In one scenario, demand for dysprosium and neodymium could be higher than 2,600 and 700 percent respectively. To meet that need, production of dysprosium would have to grow each year at nearly twice the historic growth rate for rare earth supplies. “Although the RE [rare earth] supply base has demonstrated an impressive ability to expand over recent history, even the RE industry may struggle to keep up with that pace of demand growth,” the authors said. But they also point out that shortfalls in future supply could be mitigated “through materials substitution, improved efficiency, and the increased reuse, recycling, and use of scrap.”

Source:  American Chemical Society


Additional Information:

• Evaluating Rare Earth Element Availability: A Case with Revolutionary Demand from Clean Technologies

Related Information:

• DOE: Rare earth shortages may damage clean tech growth 

• Broad scientific approach to studying rare earth materials needed to ensure continued deployment of clean energy technologies

• The Rare-Earth Crisis 

• No future without scarce metals: the scarcity of raw materials 

• Bloomberg articles, "Rare Earth Prices Double in Two Weeks as China Seeks to Increase Control" and "BMW Carbon Factory Lets Motor Vehicles Follow Road Bike to Lightness: Cars

Fuel cell technology could be under your car bonnet by 2017

Engineerblogger
March 8, 2012

Credit: Carbon Trust

Carbon Trust has given a £1m boost to four UK fuel cell pioneers. Their cutting-edge technology could be used under the bonnet of mass-produced hydrogen-powered cars as early as 2017. Major manufacturers have already built hydrogen-powered fuel cell cars, but the real challenge is to bring down the costs and, in the global race to do this, UK technologies are now in pole position.

Having identified an opportunity to combine innovative technology from Runcorn-based ACAL Energy and Sheffield-based ITM Power, the Carbon Trust is providing £500k of funding to the companies to develop a new hybrid high-power, low-cost fuel cell design.

Carbon Trust is also backing a project based at Imperial College London (Imperial) and University College London (UCL) with £500k to develop a fuel cell that could offer significant cost savings by using existing high-volume manufacturing techniques employed in the production of printed circuit boards.

The funding comes from the Carbon Trust’s Polymer Fuel Cells Challenge (PFCC) which was launched in 2009 to support the Department for Energy and Climate Change’s objectives to develop lower cost fuel cells and coincides with the recent launch of the Government’s UKH2Mobility project to ensure the UK is well positioned for the commercial roll-out of hydrogen fuel cell vehicles.

Dr Ben Graziano, Technology Commercialisation Manager at the Carbon Trust, said:

“The UK’s home-grown automotive industry hasn’t been the runaway success story many would have hoped for, but British technology is in pole position to be under the bonnet of a next generation of mass-produced hydrogen-powered cars. After a lot of hype, fuel cell technology is now a great growth opportunity for the UK. The funding that we have received from the Department for Energy and Climate Change has enabled us to support the development of some truly world-class British technologies that could slash the costs of fuel cells and transform how we all get about; by 2017 British fuel cell technologies could be powering your car.”

Simon Bourne, CTO, ITM Power Plc, said:

“The PFCC has afforded ITM the opportunity to build on its ground breaking laboratory results via a structured programme to de-risk its membrane technology. With the high level introductions the Carbon Trust has made with commercial end users and the continued success of subsequent material evaluation studies, ITM is in a very strong position to exploit this exciting new fuel cell technology.”

Amanda Lyne, VP of Strategic Business Development and Marketing, ACAL Energy Ltd said:

"It is excellent news that automotive OEMs are committed to the launch of hydrogen fuel cell electric vehicles in 2015 timescales, and that the UK will be among the early adopters. However it is clear that continuous efforts to reduce cost will be necessary to ensure that H2FC vehicles are affordable for mass markets. This funding from the Carbon Trust PFCC is perfectly targeted to ensure that British innovation can be at the forefront of the process to get the economics of the technology right."

Carbon Trust’s Polymer Fuel Cells Challenge aims to speed the UK towards world-beating fuel cell solutions that can grab a significant share of a market that the Carbon Trust has estimated to be worth $26bn in 2020. About the projects:

ACAL Energy/ITM Power

Carbon Trust, which has already supported ACAL Energy and ITM Power in de-risking their unique technologies, saw an opportunity to combine these innovations to demonstrate a fuel cell that could be far cheaper to manufacture, more efficient, produce the required power and be compact enough to fit under the bonnet of tomorrow’s cars. ACAL Energy brings a revolutionary new design of fuel cell inspired by the human lung and bloodstream that is highly durable, virtually platinum-free and also significantly cheaper to produce. ITM Power brings a unique membrane technology (which has been evaluated by several global companies), proven to produce world-beating power density (widely recognised as the single most important factor in reducing fuel cell costs), which could be in fuel cell cars by as early as 2017.

ITM’s current order book for delivery in the current financial year is £0.5m. The company has recruited seven staff in the last 12 months and is currently seeking to recruit ten more. ACAL Energy has raised £6.1m of investment since March 2010 and its staff is set to increase from 25 at that time to 35 by April 2012.

Imperial/UCL

The Imperial and UCL project is developing a fuel cell stack that could offer significant cost savings by using existing high-volume manufacturing techniques employed in the production of printed circuit boards. By simplifying the design and manufacture, this could reduce the costs of a fuel cell stack by more than 20%. Imperial Innovations and UCL Business are collaborating with the project to assist commercialisation of the technology.

Source:  Carbon Trust

Related Information:

• Fuel Cell

• Polymer Fuel Cells

Engineering research and development spurring U.S. toward energy security

Engineerblogger
March 8, 2012

Breakthroughs in engineering research and development have helped launch the U.S. on the path toward elusive energy independence, NPR reports.

With gas prices continuing to spike throughout the U.S, Americans have increasingly called on the Obama Administration to support policies that would bolster the nation's fuel production. While President Obama has publicly championed an "all of the above" energy strategy – one that promotes domestic drilling, improves fuel efficiency and develops alternative energy technologies – energy experts contend the U.S. has made significant strides over the past decade in reducing its reliance on foreign countries for oil, natural gas and other fossil fuels.

"Energy self-sufficiency is now in sight," energy economist Phil Verleger told the news provider.

Verleger and other experts assert that engineering tools and breakthroughs in industrial engineering research have helped augment oil and gas supplies in the U.S. He and other scientists contend that hydraulic fracturing – more commonly known as fracking – and other advanced drilling techniques have allowed the U.S. to tap into previously unattainable natural gas and oil reserves throughout the U.S.

Though fracking remains exceedingly controversial, such drilling wells have fueled U.S. natural gas production over the past few years, as companies have increasingly exploited resources in states such as Pennsylvania, West Virginia, North Dakota and Texas. Verleger said that the uptick in the nation's energy supplies results from the success of private research and development.

"This is really the classic success of American entrepreneurs," Verleger noted. "These were people who saw this coming, managed to assemble the capital and go ahead."

While the U.S. has historically relied upon other countries for the majority of its energy needs, it could become the world's largest producer of natural gas and oil by the end of the decade, according to PFC Energy chief executive Robin West.

"This shale gale, I describe it as the energy equivalent of the Berlin Wall coming down. This is a big deal," West said, referring to the widespread use of fracking and advanced drilling techniques. "We estimate that by 2020, the U.S. overall will be the largest hydrocarbon producer in the world; bigger than Russia or Saudi Arabia."

Though many experts caution against estimating when the U.S. will achieve the nebulous goal of energy independence, experts such as West and Verleger contend the uptick in domestic hydrocarbon production will ultimately increase energy security. If the U.S. continues on its current energy course, it would enable the country to reduce its reliance on unstable oil and natural gas producers in the Middle East, experts say.

Source: Knovel

The World's First Sterilizable Flexible Organic Transistor

Engineerblogger
March 7, 2012

Figure 1: A highly thermostable organic transistor manufactured on a thin plastic film. The team succeeded in building a low drive-voltage and a high thermostable organic circuit on a plastic film by using SAM molecule for the gate insulator, and high heat resistant semiconductors for semiconductor layer.

An international research team has succeeded in manufacturing on a polymeric film the world’s first flexible organic transistor that is robust enough under high temperature medical sterilization process. The study published online in Nature Communications on March 6, 2012.

In a serious aging society with a declining birthrate, electronics are increasing their importance in the health and medical area as more IT devices are being introduced. Upon this background, an expectation is getting higher on an organic transistor, which is a soft electronic switch. A flexible organic transistor can easily be manufactured on a biocompatible polymeric film, and this is the reason why it is expected to adopt it to a wearable health monitor without a stress, and/or implantable devices such as a soft pace maker. For practical implementation, it is crucial (1) to make the best use of its softness and biocompatibility, simultaneously (2) to decrease driving voltage down to a few V, and (3) to decrease the risk of infections by sterilization, for a security reason. Up until now, however, the existing organic transistors had huge obstacles towards the practical usage in the health and medical field. For example, typical driving voltage for displays is high (i.e. 20 to 80 V) and/or and it is not durable under high temperature sterilization.

The team has succeeded in manufacturing on a polymeric film an organic transistor that has high thermal stability and driving voltage of 2V at the same time. The new type organic transistor can be sterilized in a standard sterilization process (150 °C heat treatment) without being deteriorated in its electrical performances. The key to realize heat resistant organic transistor is in the forming technique of an ultrathin insulator film: The team develops a technique to form extraordinarily densely packed self-assembled monolayer (SAM) films, whose thickness is as small as 2 nanometers, on a polymeric film. This allows them to elevate substrate temperature up to 150 °C without creating pinholes through SAM films during the high temperature treatment. It is believed that ultrathin monolayer film like SAM degrades easily by thermal processes; however, it is unexpectedly demonstrated that densely packed SAM is stable at 150 °C or higher. This result is also proved by systematic characterization of crystallographic structures of SAM using a synchrotron radiation beam. Furthermore, by adopting a novel encapsulation layer comprising organic/metal composite materials and extremely thermally stable and high mobility organic semiconductors, the thermal stability of organic transistors is now improved up to 150 °C.

It should be benefited more from applying this heat-resistant organic transistor to long term implantable devices, or to some medical devices such as a smart catheter. With these applications, it is expected to broaden the usage of the transistor to medical apparatus such as thin film sensor that will detect tumors, inflammations, and or cancers.

The international team is led by Dr. Takao Someya, who is a professor of the University of Tokyo (President: Jyunichi Hamada, Ph.D.), a research director of ERATO (Exploratory Research for Advanced Technology) “Someya Bio-Harmonized Electronics Project” of Japan Science and Technology Agency (JST, President: Michiharu Nnakamura, D.Sc.), and a global scholar of Princeton University (President: Shirley M. Tilghman, Ph.D.), in collaborations with Associate Professor Tsuyoshi Sekitani of the University of Tokyo and Professor Yueh-Lin (Lynn) Loo of Princeton University. This joint research project was also carried out with the following institutions: Max Planck Institute for Solid State Research, Germany, National Institute of Standards and Technology, NIST, U.S., Hiroshima University, and Nippon Kayaku Co., Japan.

Background

In consequence of a serious declining birthrate and a growing proportion of elderly, information technology (IT) devices are rapidly introduced in the health and medical area. One of the good examples is the internet connection of a healthcare device between a patient’s home and a hospital. The internet allowed a doctor to monitor patience’s heart rates and weights away from his/her home. The miniaturization of medical apparatuses such as endoscopes succeeded in minimizing patients’ burdens and/or invasiveness. In this way, in the medical and the healthcare field, electronics are increasing their importance. Indeed, in the health and medical market, electronics are expected to grow 120% every year successively until 2015.

In this background, an organic transistor, which is a flexible electronic switch, attracts much attention because it is easily manufactured on a biocompatible polymeric film. A biocompatible organic transistor would be suitable for applications to a stress free wearable health monitoring system and implantable devices such as a soft pacemaker. For practical implementation, it is crucial (1) to make the best use of its softness and biocompatibility, simultaneously (2) to decrease driving voltage down to a few V, and (3) to decrease the risk of infections by sterilization, for a security reason. Up until now, however, the existing organic transistors had huge obstacles towards the practical usage in the health and medical field. For example, typical driving voltage for displays is high (i.e. 20 to 80 V) and/or and it is not durable under high temperature sterilization.

Results in details

The team has succeeded in manufacturing on a polymeric film an organic transistor that has world’s first 150 °C thermostability and simultaneously its driving voltage of 2V. The keys to realize the heat resistant organic transistor are (1) self-assembled monolayer (SAM) and (2) a sealing film, which are to be discussed later. The highly thermal stability that we had realized exploded the typical theory that an ultrathin monolayer film of nanometers in size was easily affected by heat. This result was also proved by the systematic analysis of precise crystallographic characterizations using a synchrotron radiation beam, which will be described in (3) in detail. Furthermore, the organic transistor has successfully been sterilized under a standard sterilization process (150 °C heat treatment) without being electrically deteriorated. This will be discussed in (4).

(1) Highly thermostable self-assembled monolayer (SAM) gate insulator

A key technology towards the development of sterilizable organic transistor is the 2-nm-thick ultrathin self-assembled monolayer (SAM) film. To reduce a thickness of a gate insulator film is known as the effective way to reduce the driving voltage of an organic transistor. From the security reasons, it is necessary to thin down a gate insulator film to a few nanometers thickness in order to reduce the driving voltage down to 2V. The team employed SAM film for a gate insulator in the past. They attempted to optimize manufacturing process of SAM from heat resistance point of view. As a result, by substantially improving crystalline ordering of densely packed SAM films on a polymeric film, they succeed in forming an insulator film that does not create pinholes, the cause of a leakage current, even under a high heat treatment. This becomes possible by optimizing plasma condition during the shaping process of aluminum-oxide thin films on top of the polymeric film, resulting in a way to avoid the film from being damaged during a plasma process.

(2) An encapsulation layer comprising organic and metal composite films

An improvement of thermal stability of a SAM gate insulator is not enough to accomplish the high thermal stability of an organic transistor. Normally, organic semiconductors that compose the channel layer in organic transistor are known to be easily degraded by heat. Thereby, an organic semiconductor, which is carefully chosen among heat resistant materials, is dinaphtho-thieno-thiophene (DNTT) in the experiment. Furthermore, after manufacturing an organic transistor, the transistor is completely covered by a flexible, heat-resistant encapsulation layer comprising organic and metal composite films (Figure 2). The encapsulation layer restrains DNTT from subliming with heat, and it prevents elements from substantial deterioration. Moreover, it is demonstrated that electronic characteristic of organic transistor remains practically unchanged even after dipped in the boiling water.

Figure 2: A schematic device structure (a) and a picture (b) of a thermally stable organic transistor. An organic transistor is covered with a flexible encapsulation layer that has both sealing characteristic as well as thermal stability.

(3) Structural characterization of nanometer-thick films by synchrotron radiation beams

The crystallographic structures of SAM films are examined. To be accurate, the gate insulator film used in the experiment consists of two layers, namely, 4-nm-thick aluminum-oxide and 2-nm-thick self-assembled monolayer. The thermal resistance of aluminum-oxide has been long known; however, there has been no report published on a structural analysis on SAM film, nor a report to prove structural stability of SAM film embedded in the devices at high temperature. This is because of the difficulty in analyzing the structure of such a thin SAM film with single molecular layer thickness using x-ray analysis.

The team attempted to precisely characterize crystallographic structures of a SAM film in order to evaluate the heat resistance of an organic transistor. Note that the thickness of a SAM film is as small as 2 nanometers. By using a synchrotron radiation beam, it is proven, for the very first time, to the best of our knowledge, that crystallographic structure of a SAM film exhibits any deterioration in molecular ordering even at 150 °C or higher temperature. This outcome unexpectedly overthrew what it had been believed that an ultrathin monolayer film of a few nanometers thinness must degrade easily by heat.

The analysis was carried out together with Professor Yueh-Lin (Lynn) Loo from Princeton University and a group at NIST, and a synchrotron radiation beam at Brookhaven National Laboratory is used.

(4) The creation of medical flexible electronics

The high thermostable organic transistors are capable of being sterilized without electrically deteriorated. The team evaluated elements’ heat resistance for three different standard heating sterilization processes that are widely used to sterilize medical apparatuses: they are (1) a heat treatment at a temperature of 150 °C for 20 seconds at atmospheric pressure, (2) a heat treatment at 2 atmospheric pressures, 121 °C for 20 seconds, and (3) a sterilization by boiling.

First, the thermal stability of the manufactured organic transistor is improved by annealing process at 160 °C, which is slightly high than the typical annealing temperature for sterilization. Second, bacteria are cultured on the above mentioned transistor. Finally, the number of bacteria and the electric characteristics are measured before and after the medical sterilization process. As a result, almost all the bacteria died off after the sterilization; however, electrical characteristics of the transistor are practically unchanged (a negligible level).

The team’s development in the past

Unlike the conventional inorganic materials, organic transistors are capable of making lightweight and mechanically flexible electronic devices, since they can be built on polymeric film by a low temperature processing. Organic transistors can be manufactured through printing process as well: This allowed a drastic cost reduction when making large area transistors, compared with those made with silicon. One of the major driving applications for organic transistors is e-paper. Up until now, Someya and his coworkers have intensively investigated the application of organic transistors to large-area sensors or large-area actuators. The team has shown the feasiblity of implementing organic transistors to large area electronics. A series of their achievements include a robot e-skin (2003), a sheet type scanner (2004), an ultrathin braille sheet display (2005), a wireless power transmission sheet (2006), a communication sheet (2007), an ultrasonic sheet (2008), a flash memory (2009).

Recently, organic transistors are longed to be implemented to medical and healthcare devices because of their biocompatibility. However, it is indispensable that those devices are sterilized. Therefore, it has been required that those organic circuits built on plastic films to be stable through heat treatment, and that they are driven with low voltage.

Someya and his coworkers have succeeded in making an organic transistor which stays undeteriorated after heating up to 150 °C in 2004. Though, a thick organic polymer that was used as an insulator film caused the driving voltage to be very high, and it was the reason why it did not suit for bio/medical usage. The team had attempted to build a few nm organic/inorganic materials on a plastic film using a molecular self-assembly, and they have finally proved the feasibility of heat resistance of SAM film for the first time.

In the last year, they invented a new medical electronics called “an intelligent catheter” using flexible organic transistor technique: the new narrow catheter is covered with a pressure sensor network (published in Nature Materials, UK in 2010). It was inevitable to develop a thermostable organic transistor so that the new catheter to be used practically at the hospitals. They finally overcame the barrier.

Outlook for the future

Organic transistors are mechanically flexible and expectedly biocompatible since they are made of soft organic electronic materials such as organic semiconductors. Attractive applications that are expected to be realized by flexible biocompatible organic transistors include “a wearable electronics” which reads out bio-information from outside of a skin, or “an implantable electronics” that directly extracts bio-information by implanting the electronics in a body. Indeed, Someya and his coworker also came up with applying the ultraflexible organic electronics to cover a narrow catheter. This opens a new path to the development of a thin film sensor that detects tumors, inflammations, early cancers. The invention will surely broaden the usage of the organic transistors as medical devices. Since a flexibility, a large coverage, and an electric stability are indispensable for implementation of these medical devices, the present invention will serve as the core technology when developing the future medical devices.

Up to this point, displays and solar cells have been considered as main driving applications of organic devices. Organic EL displays and organic flexible solar cells are implemented rapidly. However, they are only a glimpse of vast potentials that organic devices possess. Indeed, world’s researchers are competing in developing health and medical applications utilizing softness of organic devices. The team has led the field of flexible devices by achieving the world’s smallest minimum bending radius (100 µm). With the feasibility shown with these sterilizable, flexible organic transistors, the contribution will accelerate the researches on the medical applications.

Source: University of Tokyo via Brookhaven National Laboratory

Additional Information:

• The paper " Organic transistors with high thermal stability for medical applications" published online in Nature Communications on March 6, 2012

Robotic surgery popular, expensive, but is it more effective?

Medill Reports
March 7, 2012

Da Vinci surgeries like this one may not be any more effective than the cheaper traditional surgeries. Credit: Lisa Weidenfeld/MEDILL

The new Da Vinci surgical robot is a hit with patients, who request it for all kinds of procedures. But is it really more effective than traditional surgery -- or just more expensive? Some doctors argue that without much authoritative research, the Da Vinci robot is more a marketing tool than an improvement to surgery.

Surgeries performed with the new, high-tech, da Vinci robot use a narrower blade and provide greater precision than traditional open surgeries, which are performed with a scalpel. The machines are maneuvered by a surgeon operating the robotic arms from behind a nearby console.

There are 2,132 da Vinci systems world-wide, said Chris Simmonds, senior director of marketing services for manufacturer Intuitive Surgical, Inc. and that number is growing. But they do not come cheap. The machines each cost between $1.1 million and $2 million, with an additional cost of $100 thousand to $180 thousand for maintenance annually.

In a 2011 study from Johns Hopkins University about the marketing of the da Vinci robot, 41 percent of hospital websites included a description of robotic surgery, with 89 percent of those descriptions claiming clinical superiority. Despite this claim, only 2 percent of those hospitals made a specific comparison to open or laparoscopic surgery, which involves inserting a camera through an incision. The marketing for robotic surgery may win over more converts than the results of the surgeries.

“You start to see this is not just a trivial issue of exuberant marketing, but it is in some cases potentially inaccurate and really harmful, potentially harmful information, wrapped in the glitz and the glamor of a new technology,” said Gary Schwitzer, publisher of HealthNewsReview.org, a site devoted to reviewing media coverage of “medical treatments, tests, products and procedures.” Schwitzer has been reporting on health issues for more than 30 years.
To read more click here...

Researchers Discover New Method of Making Nanoparticles

Engineerblogger
March 6, 2012

Keith Roper, University of Arkansas

An engineering researcher at the University of Arkansas and his colleagues at the University of Utah have discovered a new method of making nanoparticles and nanofilms to be used in developing better electronic devices, biosensors and certain types of high-powered and highly specific microscopes used for scientific research.

The never-ending quest to build faster, more efficient and more reliable electronic devices starts deep down below the molecular level, where nanoparticles – far too small for the human eye to detect – make up the building blocks of the latest processing hardware. In pursuit of this goal, scientists and engineers are constantly investigating new materials and better methods of developing or assembling these materials.

The researchers’ nanoparticles, made of gold and deposited onto silicon substrates by a unique chemical process, are nontoxic and inexpensive to make and have superior dimensions, densities and distribution when compared to other nanoparticles and conventional methods of producing nanoparticles. The unique deposition technique has the further advantage of being able to rapidly coat fragile, three-dimensional and internal surfaces at the temperature and pressure of its surroundings without requiring conductive substrates or expensive, sophisticated equipment.

“Using successive thermal treatments, we characterized optical and structural features of an inexpensive, molecule-to-molecule, bottoms-up approach to create thermally stable, gold-nanoparticle ensembles on silica,” said Keith Roper, associate professor of chemical engineering at the University of Arkansas. “Images and analysis from scanning electron microscopy and atomic force microscopy revealed that particle densities are the highest reported to date. Our method also allows faster preparation than self-assembly or lithography and allows directed assembly of nanoparticle ensembles on 3D surfaces.”

The researchers’ unique approach improves upon a method that involves depositing atoms from a solution onto a substrate with a tin-sensitized surface. The researchers use a novel continuous-deposition process and then heat these deposited atoms to transform “islands” of nanoparticle material into desired forms. The resulting spherical nanoparticles can have diameters between 5 and about 300 nanometers. A nanometer is a billionth of a meter. A human hair typically has a diameter of 70,000 nanometers.

Roper said that microscopic images and spectroscopic data suggest that ultrathin films prepared by their new approach are smoother than conventional “sputtered” or evaporated gold films and may exhibit better optical features, such as reduced surface-roughness scattering. These features are desirable in devices such as photovoltaic cells in which narrow metal layers significantly affect local electromagnetic fields. Smoother thin films also could improve the limits of detection, sensitivity and photocurrent, respectively, in such applications.

The researchers’ recent studies in this area have been published in Langmuir and Journal of Physical Chemistry C, journals of the American Chemical Society. The researchers were awarded U.S. Patent No. 8,097,295 on Jan. 17 for the development.

Roper is holder of the Charles W. Oxford Professorship of Emerging Technologies. He is also assistant director of the graduate program in microelectronics/photonics.

Source:  University of Arkansas

Student Innovation at Rensselaer Polytechnic Institute Could Enable Better, Cheaper Detection of Hazardous Gases

Engineerblogger
March 6, 2012

Credit: RPI

Fazel Yavari has developed a new sensor to detect extremely small quantities of hazardous gases. Made from a 3-D foam of the world’s thinnest material—graphene—this sensor is durable, inexpensive to make, and opens the door to a new generation of gas detectors for use by bomb squads, defense and law enforcement officials, as well as applications in industrial settings.

Yavari, a doctoral student in the Department of Mechanical, Aerospace, and Nuclear Engineering at Rensselaer Polytechnic Institute, is one of three finalists for the 2012 $30,000 Lemelson-MIT Rensselaer Student Prize. A public ceremony announcing this year’s winner will be held at 6:45 p.m. on Wednesday, March 7, in the auditorium of the Rensselaer Center for Biotechnology and Interdisciplinary Studies. For more information on the ceremony visit: http://www.eng.rpi.edu/lemelson

Fazel Yavari: Credit: RPI

Yavari’s project is titled “High Sensitivity Detection of Hazardous Gases Using a Graphene Foam Network,” and his faculty adviser is Nikhil Koratkar, professor of mechanical, aerospace, and nuclear engineering at Rensselaer.

Detecting trace amounts of hazardous gases present within air is a critical safety and health consideration in many different situations, from industrial manufacturing and chemical processing to bomb detection and environmental monitoring. Conventional gas sensors are either too bulky and expensive, which limits their use in many applications, or they are not sensitive enough to detect trace amounts of gases. Also, many commercial sensors require very high temperatures in order to adequately detect gases, and in turn require large amounts of power.

Researchers have long sought to leverage the power of nanomaterials for gas detection. Individual nanostructures like graphene, an atom-thick sheet of carbon atoms arranged like a nanoscale chicken-wire fence, are extremely sensitive to chemical changes. However, creating a device based on a single nanostructure is costly, highly complex, and the resulting devices are extremely fragile, prone to failure, and offer inconsistent readings.

Yavari has overcome these hurdles and created a device that combines the high sensitivity of a nanostructured material with the durability, low price, and ease of use of a macroscopic device. His new graphene foam sensor, about the size of a postage stamp and as thick as felt, works at room temperature, is considerably less expensive to make, and still very sensitive to tiny amounts of gases. The sensor works by reading the changes in the graphene foam’s electrical conductivity as it encounters gas particles and they stick to the foam’s surface. Another benefit of the Yavari’s device is its ability to quickly and easily remove these stuck chemicals by applying a small electric current.

The new graphene foam sensor has been engineered to detect the gases ammonia and nitrogen dioxide, but can be configured to work with other gases as well. Ammonia detection is important as the gas is commonly used in industrial processes, and ammonia is a byproduct of several explosives. Nitrogen dioxide is also a byproduct of several explosives, as well as a closely monitored pollutant found in combustion exhaust and auto emissions. Yavari’s sensor can detect both gases in quantities as small as 0.5 parts-per-million at room temperature.

When he’s not studying or working in the lab, Yavari likes to keep active by playing tennis, cycling, or skiing. He also enjoys making time to travel around the United States and overseas. At home in Isfahan, Iran, Yavari’s parents are both high school teachers. They encouraged him as a child to study math and science, and today they are very proud of his accomplishments and cheering for him to win the $30,000 Lemelson-MIT Rensselaer Student Prize.

Yavari received his bachelor’s degree in mechanical engineering from Shahrekord University in Iran, and his master’s degrees in mechanical engineering from the University of Tehran.

After earning his doctoral degree later this year, Yavari plans to continue conducting research either in academia or the private sector.

About the $30,000 Lemelson-MIT Rensselaer Student Prize
The $30,000 Lemelson-MIT Rensselaer Student Prize is funded through a partnership with the Lemelson-MIT Program, which has awarded the $30,000 Lemelson-MIT Student Prize to outstanding student inventors at MIT since 1995.

ABOUT THE LEMELSON-MIT PROGRAMCelebrating innovation, inspiring youth

The Lemelson-MIT Program celebrates outstanding innovators and inspires young people to pursue creative lives and careers through invention.

Jerome H. Lemelson, one of U.S. history’s most prolific inventors, and his wife, Dorothy, founded the Lemelson-MIT Program at the Massachusetts Institute of Technology in 1994. It is funded by The Lemelson Foundation and administered by the School of Engineering. The Foundation sparks, sustains, and celebrates innovation and the inventive spirit. It supports projects in the U.S. and developing countries that nurture innovators and unleash invention to advance economic, social, and environmentally sustainable development. To date The Lemelson Foundation has donated or committed more than U.S. $150 million in support of its mission.

Source: Rensselaer Polytechnic Institute (RPI)


Additional Information:

• The report "High Sensitivity Gas Detection Using a Macroscopic Three-Dimensional Graphene Foam Network" in the Nature Scientific Report.

Is Seaweed the Future of Biofuel?

Engineerblogger
March 6, 2012

Credit: TAU

As scientists continue the hunt for energy sources that are safer, cleaner alternatives to fossil fuel, an ever-increasing amount of valuable farmland is being used to produce bioethanol, a source of transportation fuel. And while land-bound sources are renewable, economists and ecologists fear that diverting crops to produce fuel will limit food resources and drive up costs.

Now, Prof. Avigdor Abelson of Tel Aviv University's Department of Zoology and the new Renewable Energy Center, and his colleagues Dr. Alvaro Israel of the Israel Oceanography Institute, Prof. Aharon Gedanken of Bar-Ilan University, Dr. Ariel Kushmaro of Ben-Gurion University, and their Ph.D. student Leor Korzen, have gone to the seas in the quest for a renewable energy source that doesn't endanger natural habitats, biodiversity, or human food sources.He says that marine macroalgae — common seaweed — can be grown more quickly than land-based crops and harvested as fuel without sacrificing usable land. It's a promising source of bioethanol that has remained virtually unexplored until now.

The researchers are now developing methods for growing and harvesting seaweed as a source of renewable energy. Not only can the macroalgae be grown unobtrusively along coastlines, Prof. Abelson notes, they can also clear the water of excessive nutrients — caused by human waste or aquaculture — which disturb the marine environment.

A man-made "ecosystem"

While biomasses grown on land have the potential to inflict damage on the environment, the researchers believe that producing biofuel from seaweed-based sources could even solve problems that already exist within the marine environment. Many coastal regions, including the Red Sea in the south of Israel, have suffered from eutrophication — pollution caused by human waste and fish farming, which leads to excessive amounts of nutrients and detrimental algae, ultimately harming endangered coral reefs.

Encouraging the growth of seaweed for eventual conversion into biofuel could solve these environmental problems. The system that the researchers are developing, called the "Combined Aquaculture Multi-Use Systems" (CAMUS), takes into account the realities of the marine environment and human activity in it. Ultimately, all of these factors function together to create a synthetic "man-made ecosystem," explains Prof. Abelson.

Man-made fish feeders, which produce pollution in the form of excess nutrients and are generally considered harmful to the marine environment, would become a positive link in this chain. Used alongside an increased population of filter feeders such as oysters, which suck in extra particles and convert them food that the microalgae can consume, this "pollution" could be used to sustain a much greater yield of seaweed, which is needed for seaweed to become a sustainable source of fuel.

"By employing multiple species, CAMUS can turn waste into productive resources such as biofuel, at the same time reducing pollution's impact on the local ecosystem," he says.

Turning waste into opportunity

The researchers are now working to increase the carbohydrate and sugar contents of the seaweed for efficient fermentation into bioethanol, and they believe that macroalgae will be a major source for biofuel in the future. The CAMUS system could turn seaweed into a sustainable bioethanol source that is productive, efficient, and cost-effective.

Source: Tel Aviv University

Printing Muscle: 3D printer creates human tissues that could help speed drug discovery

Engineerblogger
March 5, 2012
 

Credit: Frank Rogozienski/Wonderful Machine

In a small clean room tucked into the back of San Diego–based startup Organovo, Chirag Khatiwala is building a thin layer of human skeletal muscle. He inserts a cartridge of specially prepared muscle cells into a 3-D printer, which then deposits them in uniform, closely spaced lines in a petri dish. This arrangement allows the cells to grow and interact until they form working muscle tissue that is nearly indistinguishable from something removed from a human subject.

The technology could fill a critical need. Many potential drugs that seem promising when tested in cell cultures or animals fail in clinical trials because cultures and animals are very different from human tissue. Because Organovo's product is so similar to human tissue, it could help researchers identify drugs that will fail long before they reach clinical trials, potentially saving drug companies billions of dollars. So far, Organovo has built tissue of several types, including cardiac muscle, lung, and blood vessels.

Unlike some experimental approaches that have used ink-jet printers to deposit cells, Organovo's technology enables cells to interact with each other much the way they do in the body. They are packed tightly together and incubated, prompting them to adhere to each other and trade chemical signals. When they're printed, the cells are kept bunched together in a paste that helps them grow, migrate, and align themselves properly. ­Muscle cells, for example, orient themselves in the same direction to create tissue that can contract.

So far, Organovo has made only small pieces of tissue, but its ultimate goal is to use its 3-D printer to make complete organs for transplants. Because the organs would be printed from a patient's own cells, there would be less danger of rejection.

Organovo plans to fund its organ-­printing research with revenue from printing tissues to aid in drug development. The company is undertaking experiments to prove that its technology can help researchers detect drug toxicity earlier than is possible with other tests, and it is setting up partnerships with major companies, starting with the drug giant Pfizer.

Source: Technology Review

Robotics: Present state and future trends

Engineerblogger
March 5, 2012

Grunt work: This concept for a military robot would continue the tradition of machines taking on jobs that are dirty or dangerous

Contemporary robots are used for jobs that are boring, dirty, or dangerous; or for tasks that require more speed, precision, or endurance than a human can provide.

They perform almost all welding, painting, and assembly tasks in the automotive industry and have become a basic element of production in industries ranging from electronics to wood products. According to World Robotics, a 2008 report published by the International Federation of Robotics, the estimated number of industrial robots installed worldwide is more than one million—50% in Asia and Australia, 33% in Europe, and 17% in North America.

An assessment of the international state of robotics R&D published in 2006 by the nonprofit analysis World Technology Evaluation Center (WTEC), found that the U.S. was leading in robot navigation in outdoor environments, robot architectures (the integration of control, structure, and computation), and in applications to space, defense, underwater systems, and some aspects of service and personal robots.

Japan and Korea lead in technology for robot mobility, humanlike robots, and some aspects of service and personal robots (including entertainment). Europe led in mobility for structured environments, including urban transportation. Europe also has significant programs in elder care and home service robotics. Australia led in commercial applications of field robotics, particularly in such areas as cargo handling and mining, as well as in the theory and application of localization and navigation.

The panel also reported that the U.S. lost its preeminence in industrial robotics at the end of the 1980s, and nearly all its robots for welding, painting, and assembly are imported from Japan or Europe.

Cognitive robots can be used as home helpers, caregivers, or emergency and rescue aids.

U.S. R&D efforts on robotics have focused primarily on military and defense-related applications—unmanned aerial, ground, and maritime systems, both surface and undersea. The Department of Defense plans to develop an increasingly sophisticated force of unmanned systems over the next 25 years and expects to integrate them with manned systems.

In 2009, the DOD published the 25-year, unmanned-systems integrated roadmap to 2034. In July 2008, the Robotics Technology Consortium, Inc., was formed with 70 initial organizations, to speed the creation and deployment of ground robotics technology for the DOD and other U.S. government agencies. It has since grown to more than 200 member organizations.

A congressional robotics caucus was formed in 2007 to broaden awareness among members of Congress and policy analysts of key issues facing the U.S. robotics industry. In May 2009, the caucus published A Roadmap for U.S. Robotics: From Internet to Robotics, a targeted R&D roadmap for nonmilitary applications of robotics in manufacturing, in medical and healthcare, in domestic and professional services, and in emerging technologies.

In 2005, the European Robotics Technology Platform was formed to strengthen links between academia and industry, and to develop a research agenda of European robotics. In 2009, the industry group Coordination Action for Robotics in Europe (CARE) also published the Strategic Research Agenda for Robotics.

In Japan, the Ministry of Economy, Trade, and Industry has sponsored robotics activities for a long time. A 2007 national technology roadmap by the Trade Ministry called for one million robots to be installed throughout the country by 2025.

To alleviate a workforce shortage in the country, robots are expected to fill the jobs of 3.5 million people by 2025. The Japanese government also estimates that the nation may save as much as $21 billion on insurance payments in the same year by using robots to monitor the health of elderly people.

In South Korea, a 10-year robotics initiative was launched along with a detailed roadmap to make the country the second-largest provider of robotics in the world, after Japan. Robot Land, a theme park being built near Seoul, is expected to open in 2013. The country’s forecasts include placing a robot in every household by 2020.

Future Environments

The convergence of technologies involving computing, communication, and intelligent interfaces with autonomous robotics suggests that networks of intelligent, autonomous robots may become the next disruptive technology.

The concept of networking everyday objects and appliances in an ambient intelligent environment is not new. But the focus has usually been on the creation, delivery, and sharing of information, and not on the performance of physical tasks.

Autonomous mobile robots may one day perform complex medical procedures, including surgery, on patients in dangerous or remote locations from battlefields to space, with little human guidance. Advances in miniaturization and bionanotechnology could lead to a new generation of nanorobots, which would revolutionize the medical industry. Nanobots may provide treatment at the cellular level, perhaps clearing clogged arteries, repairing genes, battling cancer cells, and delivering drugs.

Cognitive robots can become available as office helpers or as robotic companions for guiding the blind and assisting the elderly. General-purpose anthropomorphic robots, with human-like hands, can be used in transforming manufacturing from resource-intensive to knowledge-intensive, and creating totally unmanned factories. Agricultural robotic scouts may roam the fields of the future to care for the plants, use sensors to provide detailed real-time information about the status of the crop, and apply data fusion techniques for making management decisions.

Source: ASME

Heart-powered pacemaker could one day eliminate battery-replacement surgery

Engineerblogger
March 5, 2012

An artificial pacemaker from St. Jude Medical, with electrode.

A new power scheme for cardiac pacemakers turns to an unlikely source: vibrations from heartbeats themselves.

Engineering researchers at the University of Michigan designed a device that harvests energy from the reverberation of heartbeats through the chest and converts it to electricity to run a pacemaker or an implanted defibrillator. These mini-medical machines send electrical signals to the heart to keep it beating in a healthy rhythm. By taking the place of the batteries that power them today, the new energy harvester could save patients from repeated surgeries. That's the only way today to replace the batteries, which last five to 10 years.

"The idea is to use ambient vibrations that are typically wasted and convert them to electrical energy," said Amin Karami, a research fellow in the U-M Department of Aerospace Engineering. "If you put your hand on top of your heart, you can feel these vibrations all over your torso."

The researchers haven't built a prototype yet, but they've made detailed blueprints and run simulations demonstrating that the concept would work. Here's how: A hundredth-of-an-inch thin slice of a special "piezoelectric" ceramic material would essentially catch heartbeat vibrations and briefly expand in response. Piezoelectric materials' claim to fame is that they can convert mechanical stress (which causes them to expand) into an electric voltage.

Karami and his colleague Daniel Inman, chair of Aerospace Engineering at U-M, have precisely engineered the ceramic layer to a shape that can harvest vibrations across a broad range of frequencies. They also incorporated magnets, whose additional force field can drastically boost the electric signal that results from the vibrations.

The new device could generate 10 microwatts of power, which is about eight times the amount a pacemaker needs to operate, Karami said. It always generates more energy than the pacemaker requires, and it performs at heart rates from 7 to 700 beats per minute. That's well below and above the normal range.

Karami and Inman originally designed the harvester for light unmanned airplanes, where it could generate power from wing vibrations.

A paper on the research, titled "Powering pacemakers from heartbeat vibrations using linear and nonlinear energy harvesters," is published in the current print edition of Applied Physics Letters.

The research is funded by the National Institute of Standards and Technology and the Institute for Critical Technology and Applied Science at Virginia Tech.

Source: University of Michigan

An electrical switch for magnetic current

Engineerblogger
March 2, 2012

View of a ferroelectric tunnel junction: This image created by the atomic force microscope shows the extremely regular structure of the ferroelectric lead zirconate titanite layer. The yellow bumps are the ferromagnetic cobalt electrodes. Each tunnel junction can be targeted via the cobalt electrodes.

© Marin Alexe / MPI of Microstructure Physics

A new mechanism will make it possible to switch data storage in the future. Researchers at the Max Planck Institute of Microstructure Physics in Halle use a short electric pulse to change the magnetic transport properties of a material sandwich consisting of a ferroelectric layer between two ferromagnetic materials. It could be assumed that an electric pulse only influences the electric transport properties. With the help of the new switching mechanism, information can be placed in four instead of just two states of a storage point. This consequently increases storage density. This mechanism may also prove useful in spintronics. This type of electronics should be particularly efficient at processing data, as it does not just utilise the electrons’ charge, but also their spin, which could be regarded as their own spin momentum.

Such behaviour would have quite curious effects for a light switch: In the case of a lamp dimmer switch, the connection, which the physicists at the Max Planck Institute of Microstructure Physics in Halle have discovered, would not only cause the light to change brightness, but also to change colour – from green to red, for instance. Although both properties are characteristics of light, they cannot be manipulated with one switch simultaneously. However, the researchers in Halle have now succeeded in doing something similar with the tunnel current that flows between two ferromagnetic electrode layers of a multiferroic material sandwich.

In this case, multiferroic means that the parcel includes the two ferromagnetic substances, as well as a ferroelectric substance. In ferroelectric materials, voltage switches between the two directions of an electric polarisation – depending on its polarity – not unlike when a magnetic field permanently reverses the polarity of a ferromagnet. As ions shift within the material structure during this process, the polarisation remains intact, even after the voltage has been reduced. It is possible, however, to reverse the switch again with a similarly large voltage with reversed polarity.

Changing the direction of the polarisation with electric and magnetic effects

The Halle-based researchers prepared their multiferroic material sandwich by steaming an extremely accurately structured ferromagnetic lanthan strontium manganate (LSMO) layer on a base. The thickness of this layer is just under 30 nanometres − that is one millionth of a millimetre. On top of that, they deposited a layer of ferroelectric lead zirconate titanite (PZT) only three nanometres thick and with a very regular structure; a top layer of ferromagnetic cobalt finished the sandwich.

The physicists then placed the tip of an atomic force microscope over the cobalt cover of the material stack to create voltage at the multiferroic sandwich. Although the non-conductive PZT layer prevents current flow in the traditional sense between cobalt and LSMO, some electrons may overcome the barrier in the quantum-physical tunnel process. The researchers in Halle were interested in precisely these properties of tunnel current.

The strength of this tunnel current depends on the polarisation of the ferroelectric PZT. The polarisation impacts the height of the tunnel barrier, meaning that the tunnel resistance is different for both polarisation directions. The physicists also used electrical voltage to switch between the two polarisation directions. To do this, they applied a voltage pulse, which was considerably stronger than the voltage needed for the tunnel current but lasted less than a millisecond.

“Surprisingly, not only the component of the tunnel junction resistance that depends on the direction of the polarisation, but also the component that usually only depends on the direction of the magnetisation of the electrodes, the so-called tunnel magnetoresistance, changes when reversing the polarity of the ferroelectric fluid,” says Dietrich Hesse, who heads the research team together with Marin Alexe. This tunnel magnetoresistance (TMR) always appears when electrons are tunnelling between two different ferromagnets. It is usually smaller for two ferromagnetic electrodes that are magnetised in the same direction than for two electrodes that are magnetised in opposite directions – in this case, physicists talk of normal tunnel magnetoresistance.

The physicists in Halle actually observed the normal tunnel magnetoresistance in one of the two electric polarisation directions in the ferroelectric PZT layer. In the case of the other electric polarisation direction, however, the conditions surprisingly reversed themselves – now there was inverted TMR. The tunnel connection conducts current with little resistance when both ferromagnets are magnetised in the opposite direction.

Apart from the effect on the electric resistance, the TMR also acts as an electron spin filter. In simple terms, the spin is the direction in which the electrons are spinning; it provides every electron with its own magnetic momentum, which may go one way, then the other. In the simplest case of normal TMR, only electrons whose magnetic momentum is going in the same direction as the magnetisation of the two ferromagnetic electrodes manage to get through the PZT layer. “A change in the electric polarisation direction therefore influences the strength of the tunnel current and also results in electrons with a certain spin being filtered out,” explains Marin Alexe. “We can achieve the same effect by changing the magnetisation in both ferromagnetic layers with an external magnetic field, but this method uses a lot more energy.”

The influence of the electric polarisation on the filter effect of the tunnel junction for electron spins and the electric resistance are interesting for applications, because, all in all, the multiferroic tunnel connection can take four differently sized electric resistances: two for each electric polarisation direction, one for the same magnetisation and one for opposite magnetisation of both ferromagnets. “This enables us to deposit three times as much information in a multiferroic tunnel junction than in ordinary binary magnetic storage,” comments Marin Alexe. This means that the size of magnetic random access memories (MRAM) can be considerably reduced. MRAMs provide an alternative to conventional electrically operated RAMs. They would make it unnecessary to load data from the hard drive to a user memory when booting up a computer, and the device would be ready to use at the push of a button.

Diagram of a multiferroic material sandwich: The orange-red base carries a green layer of ferromagnetic lanthan strontium manganate (LSMO). Above that is the isolating ferroelectric lead zirconate titanite (PZT) layer. The nano condensers are closed by ferromagnetic cobalt electrodes. They get their shape from correspondingly structured shadow masks. In reality, the PZT layer is considerably thinner than the LSMO layer; it is barely three nanometres thick.

© Marin Alexe / MPI of Microstructure Physics

Better understanding to pave the way for spintronics

“As a filter that can be simply switched and sort electrons according to their spin direction, the multiferroic tunnel junction could also find use in spintronics,” says Dietrich Hesse. This could be a possible future development of electronics, which is why many physicists around the world are researching its basic principles. Spintronics uses both the charge and spin of the electrons to process data with a higher density than is possible in conventional electronics.

In order to advance the multiferroic material sandwich as a spin filter, physicists are first striving to understand precisely how a change of the PZT’s electric polarisation direction affects the magnetic tunnel resistance. Up to now, they only know the details of what happens in the case of the electric polarisation direction that goes hand in hand with the normal tunnel magnetoresistance. “We are unable as yet to explain exactly why the inverted tunnel magnetoresistance appears when the polarisation direction is reversed,” comments Dietrich Hesse. One reason could be the interaction between the ferromagnetic cobalt and the adjoining titan ions in the PZT. The latter change their position with the polarisation direction. When they get closer to the cobalt layer, they take on their own magnetic momentum on account of the intensive interaction. This magnetic momentum affects the spin direction of the tunnelling electrons.

To explain this connection in detail, Dietrich Hesse and Marin Alexe asked theoretical physicists at the Institute and at the University of Halle for help. They will now calculate the magnetoelectric coupling due to the interaction between the titan ions of the PZT and the cobalt. However, the help of Dietrich Hesse’s and Marin Alexe’s team is still needed to draw a better comparison between the results of this calculation and the experiments. They are currently trying to steam the cobalt cover of their multiferroic material sandwich with a structure that is as regular as that of the other two layers. “Only if we understand exactly how the magnetoelectric coupling works in multiferroic tunnel junctions can we also use it for electronic applications.”

Source: Max-Planck-Gesellschaft

Graphene-Based Optical Modulators Poised to Break Speed Limits in Digital Communications

Engineerblogger
March 2, 2012

In yet another astounding application of the “wonder material” graphene, scientists at the University of California, Berkeley discovered that it makes an excellent active media for optical modulators. Graphene-based modulators are expected to significantly enhance ultrafast optical communication and computing. The team will report on their findings at the Optical Fiber Communication Conference and Exhibition/National Fiber Optic Engineers Conference (OFC/NFOEC) taking place next week in Los Angeles.

Modulators play a vital role in communications due to their switching ability, because this is what controls the speed that data packets can travel through networks. As the speed of data pulses sent out increases, it means that greater volumes of information can be transmitted.

“We demonstrated a graphene-based optical modulator with a broad optical bandwidth (1.35-1.6 µm), a small device footprint (25 µm2), and high operational speed (1.2 GHz at 3dB) under ambient conditions—all of which are essential for optical interconnects for future integrated optoelectronic systems,” says Ming Liu, a post-doctoral researcher working at UC Berkeley’s NSF Nanoscale Science and Engineering Center. “The modulation efficiency of a single layer of a hexagonal carbon atom is already comparable to, if not better than, traditional semiconductor materials, which are orders of magnitude larger in active volume.”

Looking into future applications, graphene-based modulators could be very compact and potentially perform at speeds up to 10 times faster than today’s technology allows. They may someday enable consumers to stream full-length, high-definition, 3-D movies onto their smartphones within mere seconds.

Liu’s talk, “Graphene-based optical modulators,” takes place Tuesday, March 6 at 3:30 p.m. in the Los Angeles Convention Center.

About OFC/NFOEC

For more than 35 years, the Optical Fiber Communication Conference and Exposition/ National Fiber Optic Engineers Conference (OFC/NFOEC) has been the premier destination for converging breakthrough research and innovation in telecommunications, optical networking and, recently, datacom and computing. Uniting service providers, systems companies, enterprise customers, IT businesses and component manufacturers, along with researchers, engineers and development teams, OFC/NFOEC combines dynamic business programming, an exposition of more than 500 companies and cutting-edge peer-reviewed research into one event that showcases the trends and pulse of the entire optical communications industry. OFC/NFOEC is managed by the Optical Society (OSA) and co-sponsored by OSA, the Institute of Electrical and Electronics Engineers/Communications Society (IEEE/ComSoc) and the IEEE Photonics Society. Acting as a non-financial technical co-sponsor is Telcordia Technologies

Source:  Optical Society of America (OSA)

Materials: Building lightweight trains

Engineerblogger
March 1, 2012

These diesel trains for housing is manufactured from a light polyurethane-based material, yet extremely durable. Source:  Fraunhofer ICT

The less trains weigh, the more economical they are to run. A new material capable of withstanding even extreme stresses has now been developed. It is suitable for a variety of applications, not least diesel engine housings on trains – and it makes these components over 35 percent lighter than their steel and aluminum counterparts.

In their efforts to render cars and trains more economical, manufacturers are trying to find lighter materials to replace those currently used. But there is a problem: Lighter materials tend not to be as tough as steel or aluminum, so they cannot simply be used in place of these metals. Rather, it is a question of manufacturers deciding which components can really afford to have weight shaved off and how to integrate them into the overall systems.

Working together with Bombardier GmbH, KraussMaffei Kunststofftechnik GmbH, Bayer MaterialScience AG, DECS GmbH, the DLR’s Institute for Vehicle Concepts, the University of Stuttgart and the Karlsruhe Institute for Technology, researchers at the Fraunhofer Institute for Chemical Technology ICT in Pfinztal have now developed a polyurethane-based sandwich material that is extremely resilient. “To demonstrate the material, we manufactured a component that is subject to significant stresses and which has to fulfill a number of requirements – the diesel engine housing for a train,” says Jan Kuppinger, a scientist at the ICT. This housing is located beneath the passenger compartment, i.e. between the car and the tracks. Not only does it shield the engine against flying stones and protect the environment from any oil that might escape, but in the event of a fire, it also stops the flames from spreading, thus meeting the flame retardant and fire safety standards for railway vehicles. Kuppinger adds: “By using this new material, we can reduce the component’s weight by over 35 percent – and cut costs by 30 percent.”

The researchers opted for a sandwich construction to ensure component stability: Glass fiber reinforced polyurethane layers form the outer facings, while the core is made of paper honeycomb. Polyurethane is a bulk plastic combining two substances. Since it can be adapted to fulfill various requirements, it is referred to as a ‘customizable material’. In foamed form it is soft, and can be used for example as a material for mattresses; in compact form it is strong and hard. The researchers began by incorporating various additives into their polyurethane, altering it in such a way as to ensure it would meet fire safety standards. Then, the partners optimized the standard manufacturing process, fiber spraying, by developing a mixing chamber which allows even more complex structures to be produced in any required size. The diesel engine housing they made is approximately 4.5 meters long and more than 2 meters wide. “This is the first time it has proved possible to use this process to manufacture such a large and complex component that also satisfies the structural requirements,” states Kuppinger. Previously, one problem encountered with fiber spraying was that it was impossible to determine the precise thickness of the polyurethane top layers. But now the researchers have found a way to do this, using computer tomography to inspect the manufactured layers and then applying a specially-adapted evaluation routine to establish their exact thickness. This information helps to simulate the strength of the component, as well as its ability to withstand stresses.

The scientists produced their diesel engine housing demonstrator as part of the PURtrain project, which is funded by the German Federal Ministry of Education and Research (BMBF). The demonstrator passed its first strength test – in which the scientists placed it in a test rig and then applied forces to it at various locations, measuring the extent to which it deformed – with flying colors. In the next stage, the researchers want to trial the component in a proper field test. If that, too, proves successful, it will then be possible to use the material to make roof segments, side flaps and wind deflectors for the automobile and commercial vehicle industry, and to ramp up the manufacturing process to produce medium volumes of between 250 and 30,000 units.

Source: Fraunhofer-Gesellschaft

Composite plastics have high conductivity and strength

Engineerblogger
March 1, 2012

A London-based start-up company has created composite plastics with both high conductivity and tensile strength.

The material, which can be made into fibres or sheets, could find a use in strain monitoring and has already been tested to this end in the sails of high-end yachts competing in the Americas Cup.

Conductive polymers have existed for some time, but are generally made from exotic semi-conducting organics, and restricted to organic solar cells, printing electronic circuits, and organic light-emitting diodes.

A team at NanoForce, a spin-off from Queen Mary University of London, set about creating robust plastics that could conduct at near-metallic levels.

‘You can just use normal polypropylene or polyamide, so they’re much more stable than these fancy semi-conducting polymers,’ Ton Peijs, technical director, told The Engineer.

The team uses additive multi-walled carbon nanotubes at a weight percentage of around one per cent. In isolation, the nanotubes show excellent metallic conduction, but the challenge has been to incorporate them into composites.

‘If I want to make a conductive polymer composite I need to mix in these nanoparticles and you don’t want them to be all agglomerated here and all agglomerated there because then they are too far apart and never form a network — but if they are all perfectly and evenly dispersed, then they are also quite far apart,’ Peijs said.

NanoForce’s solution was a post-processing technique that involves annealing and hot pressing — basically re-melting the polymer after extrusion — allowing the nanotubes to migrate into a self-organising ‘dynamic network’ that is conductive. The process can be tuned by temperature and time of annealing, and can also align the polymer units to increase the strength.

Crucially, when the resulting fibre or sheet is stretched and placed under strain, the nanotube networks that has been in place previously gets pulled apart and deforms, breaking down the connections and creating electrical resistance of several orders of magnitude. This is particularly useful for in situ monitoring of strain in various critical structures.

Indeed, NanoForce has recently done some work with North Sails for certain teams competing in the Americas Cup yacht competition.

‘It’s sort of the Formula One of sailing — actually they spend more than than Formula One — and they do a lot of analysis,’ Peijs said. ‘Using our technology they could analyse the load in the sails, what are the local strains… then, of course, you can optimise performances.’

Applied as a thin-film layer it could also be used for condition monitoring in the aerospace industry and wind turbines, for example.

Source: The Engineer

Battery to Take On Diesel and Natural Gas

Technology Review
Feb 29, 2012

Battery building: Aquion Energy recently announced plans to retrofit this factory—which used to make Sony televisions—to make large batteries for use with solar power plants. Credit: RIDC Westmoreland

Aquion Energy, a company that's making low-cost batteries for large-scale electricity storage, has selected a site for its first factory and says it's lined up the financing it needs to build it.

The company hopes its novel battery technology could allow some of the world's 1.4 billion people without electricity to get power without having to hook up to the grid.

The site for Aquion's factory is a sprawling former Sony television factory near Pittsburgh. The initial production capacity will be "hundreds" of megawatt-hours of batteries per year—the company doesn't want to be specific yet. It also isn't saying how much funding it's raised or where the money comes from, except to mention that some of it comes from the state of Pennsylvania, and that $5 million, in the form of an R&D grant, comes from the federal government.

The first applications are expected to be in countries like India, where hundreds of millions of people in communities outside major cities don't have a connection to the electrical grid or any other reliable source of electricity. Most of these communities use diesel generators for power, but high prices for oil and low prices for solar panels are making it cheaper to install solar in some cases.

To store power generated during the day for use at night, these communities need battery systems that can handle anything from tens of kilowatt-hours to a few megawatt-hours, says Scott Pearson, Aquion's CEO. Such a system could make long-distance transmission lines unnecessary, in much the same way that cell-phone towers have allowed such communities access to cellular service before they had land lines.

Eventually Aquion plans to sell stacks of batteries in countries that have electrical grids. They could provide power during times of peak demand and make up for fluctuations in power that big wind farms and solar power plants contribute to the grid. Those applications require tens to hundreds of gigawatt-hours' worth of storage, so to supply them, Aquion needs to increase its manufacturing capacity. Competing with natural-gas power plants—especially in the United States, where natural gas is so cheap—will mean waiting until economies of scale bring costs down.

The company has said that it initially hopes to make batteries for under $300 per kilowatt-hour, far cheaper than conventional lithium-ion batteries. Lead-acid batteries can be cheaper than Aquion's, but they last only two or three years. Aquion's batteries, which can be recharged 5,000 times, could last for over a decade in situations in which they're charged once a day (the company has tested the batteries for a couple of years so far).
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Tiny 3D chips: Researchers develop a new approach to producing microchips

MIT News
Feb 29, 2012

A new approach helps researchers make tiny three-dimensional structures. Pictured are two packaged microchips, each with tiny bridges fabricated on their surfaces.

Microelectromechanical systems, or MEMS, are small devices with huge potential. Typically made of components less than 100 microns in size — the diameter of a human hair — they have been used as tiny biological sensors, accelerometers, gyroscopes and actuators.

For the most part, existing MEMS devices are two-dimensional, with functional elements engineered on the surface of a chip. It was thought that operating in three dimensions — to detect acceleration, for example — would require complex manufacturing and costly merging of multiple devices in precise orientations.

Now researchers at MIT have come up with a new approach to MEMS design that enables engineers to design 3-D configurations, using existing fabrication processes; with this approach, the researchers built a MEMS device that enables 3-D sensing on a single chip. The silicon device, not much larger than Abraham Lincoln’s ear on a U.S. penny, contains microscopic elements about the width of a red blood cell that can be engineered to reach heights of hundreds of microns above the chip’s surface.

Fabio Fachin, a postdoc in the Department of Aeronautics and Astronautics, says the device may be outfitted with sensors, placed atop and underneath the chip’s minuscule bridges, to detect three-dimensional phenomena such as acceleration. Such a compact accelerometer may be useful in several applications, including autonomous space navigation, where extremely accurate resolution of three-dimensional acceleration fields is key.

“One of the main driving factors in the current MEMS industry is to try to make fully three-dimensional devices on a single chip, which would not only enable real 3-D sensing and actuation, but also yield significant cost benefits,” Fachin says. “A MEMS accelerometer could give you very accurate acceleration [measurements] with a very small footprint, which in space is critical.”

Fachin collaborated with Brian Wardle, an associate professor of aeronautics and astronautics at MIT, and Stefan Nikles, a design engineer at MEMSIC, an Andover, Mass., company that develops wireless-sensor technology. The team outlined the principles behind their 3-D approach in a paper accepted for publication in the Journal of Microelectromechanical Systems.
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The Asian Research Network: a Collaboration to Boost Science

Engineerblogger
Feb 29, 2012

Prof. Haiwon Lee: “Giving is better than taking. So I thought to myself, what about giving something to the other people in Asia? I want to give something as long as I have something to give.” Credit : Asian Research Network

Hanyang University of Korea and RIKEN of Japan, along with other Asian research institutes, are launching the Asian Research Network (ARN). Recently ARN members succeeded in producing transparent touch sensors using carbon nanotubes and ink solutions that can print electronic circuits or change colour in exposure to heat or UV radiation.

“I say to people, ‘I’m a small, skinny guy and I have a dream, I want to do something for Asia,’” beams Prof. Haiwon Lee, Director of the Institute of Nanoscience and Technology at Hanyang University in South Korea.

Small as his stature may be, Lee’s wit, enthusiasm and intelligence make up for it in fair measure. Holding more professorships, directorships and editorial posts than there is space to mention here, it is immediately clear that here is a man who does not define himself by these titles, but by his actions. In particular, it is the Asian Research Network that he speaks of with a passion often rare in professors who are comfortably at the top of their game.

In 1989, on his own accord, Lee started yearly trips to Japan—a step made all the more significant by the historical tensions between the two countries. He sought to establish relationships with other researchers and institutes, integrating science in Asia for a better future. It was a slow process. Apart from exchanges on a company or government level it was, and perhaps still is, highly unusual for a South Korean individual to be promoting research, development and educational cooperation across borders.

Step-by-step Lee built a performance-based relationship with RIKEN. Nevertheless, it was not until 2003 that an alliance between RIKEN and Hanyang was formally established. The significance was profound. Never before had Japan opened up its doors for a private research university.

Next Lee sought to obtain funding for a cooperative research laboratory to give tangible structure to the Asian Research Network. In 2008, following grants from the Korean Ministry of Education, Science and Technology, Seoul’s mayor and Samsung electronics, the Hanyang-RIKEN Collaboration Centre was established. Here researchers from both institutions could work side by side to produce world-class research.

Many would be satisfied with these achievements. For Lee however, it is just the start. The alliance needs to go across Asia. “The idea is to exchange information and relationships at a high level,” he explains. ARN is starting with tangible goals, initially focusing on the areas of nanoscience and nanotechnology. Lee points to a poster advertising a recent joint Hanyang-RIKEN nanoscience conference. However, as they expand ARN is to encompass all science and technology and include other Asian partners such as China, India and Singapore.

“Our aim is to build a borderless research environment,” says Lee. He stresses that this is not just for Korea, but also for Asia and ultimately he aims to go global. The reason that Lee has made his dream a reality is due to his insistence on a pragmatic approach. He looks to innovate, change and truly engage rather than go through set patterns and motions.

“In the beginning, I was talking to government people who would always say, ‘Show me the MOU’ said Lee. A ‘memorandum of understanding’ or ‘MOU’ is a traditional document indicating a multilateral agreement between parties. MOU’s are popular across Asia, so Lee took me by surprise when he continued matter-of-factly: “MOU’s don’t mean anything – its just politics”.

He continued, “It took five years to get people onboard. They always wanted to wait and consider things endlessly, it was very difficult.” If there is one thing that is clear about Lee, it is that he is a man of deeds, not just words, who does not shy away from getting things done.

But why put so much effort into this? I asked. Of course there are huge benefits, but most academics are more concerned with climbing up the citation league table, (and it is clear that Lee has spent at least a hundred papers worth of time establishing ARN!). He looks at me with thoughtful eyes and stares into the distance. “I was born in 1954, right after the Korean war,” he says. “I was one of eight children, there was nothing left of Korea and it was miserable. Our parents sacrificed everything for our education. They did not spend even a single penny. I am not from a rich family, my mother only went to elementary school, but because of their efforts four of us are now professors. They knew how to save material, how to manage, how to change their country. This is the strength and spirit of our parents.”

And the spirit of cooperation is certainly helping the research productivity and output of ARN members. Take for example Choi Eunsuk and colleagues; they recently announced they had made a transparent touch sensor using carbon nanotube thin films (Journal of Nanoscience and Nanotechnology, vol. 11, 2011). These films are optically transparent and electrically conductive in thin layers. The applications are enormous: think of flexible electronic interfaces such as “e-paper”, or television screens that you can roll up.

Similarly, Jong-Man Kim and his team have managed to devise an ink solution that can repeatedly change colour upon exposure to heat or UV radiation. Their results in the Journal of Advanced Materials (Vol. 23, 2011) open the possibility of printing electronic circuits on paper. Being able to integrate such circuitry into lightweight, disposable materials such as paper using simple ‘inkjet’ technology is of great interest to manufacturers.

Prof. Lee meanwhile revels in this spirit of collaboration: “Giving is better than taking. So I thought to myself, what about giving something to the other people in Asia? I want to give something as long as I have something to give.”


Source: Asian Research Network

Additional Information:

• Choi Eunsuk, Kim Jinoh, et al. "Fabrication of a flexible and transparent touch sensor using single-walled carbon nanotube thin-films" Journal of Nanoscience and Nanotechnology Vol. 11 7 pp. 5845-5849 (2011) DOI: 10.1166/jnn.2011.4450

• B. Yoon, D.-Y. Ham, O. Yarimaga, H. An , C. W. Lee, and J.-M. Kim, "Inkjet Printing of Conjugated Polymer Precursors on Paper Substrates for Colorimetric Sensing and Flexible Electrothermochromic Display", Advanced Materials, 2011, 23, 5492-5497. DOI: 10.1002/adma.201103471