Sticker shock at the gas pumps combined with concerns over the diminishing supply of nonrenewable energy sources like coal, oil and natural gas have added new urgency to the search for alternatives. Riding to the rescue are technology-based resources that will never run out, because they are renewable; are environmentally friendly, and do not add to the greenhouse effect; and are increasingly cheap to harvest, thanks to continuing technical breakthroughs. Solar is here today, but at about three times the cost of conventionally generated electricity (18 to 22 cents per kilowatt, compared with 5 to 10 cents/ kW for conventional). However, thanks to advances including the use of "plastic" solar cells to replace the more expensive silicon versions, the U.S. Department of Energy believes the cost of solar will be on par with that of conventional electricity within 10 years. By that time, two other contenders--hydrogen fuel cells and nanoscale electric generators--will be at about the same stage of development as solar cells are today. Photovoltaic solar cells work by absorbing units of light, or photons, in a semiconductor, thereby energizing its electrons enough to drive circuitry. Japan holds just 20 percent of the $3 billion to $4 billion world solar cell market today, according to Solarbuzz LLC (San Francisco). Germany has the greatest number of solar installations, accounting for 57 percent of the total in 2005, with the United States at only 7 percent, the rest of Europe at 6 percent and the rest of the world at 10 percent. Of the various solar cells available, efficiencies range from about 6 percent for the least expensive amorphous-silicon models on glass or plastic substrates to as high as 30 percent for multijunction gallium arsenide cells on monocrystalline wafers, which cost up to 100 times more. Monocrystalline and polycrystalline silicon solar cells, the most popular types, have efficiencies ranging from about 10 to 18 percent. Ready-to-install modules sell for about $4 per watt. Devices with lower conversion efficiency than mono- or polycrystalline silicon cells include amorphous silicon, cadmium telluride, copper indium diselenide and other, similar alloys. Monocrystalline and polycrystalline silicon solar cells hold 93 percent of the worldwide market today
Monday, May 29, 2006
Akustica Inc. announced last week that Fujitsu's LifeBook Q2010--a notebook aimed at no-holds-barred "road warriors" like traveling executives--will include two AKU2000 single- chip microphones located on the display's bezel. This design win indicates that high-end laptop computers are switching from analog to digital microphones, according to Akustica (Pittsburgh). At the same time, the company introduced a chip, the AKU2001, that permits multiple microphones to share a single interface wire. Codec maker SigmaTel Inc. (Austin, Texas) simultaneously announced support for the AKU2001 microphones. The compatible codec will permit designers to multiplex multiple microphones on a single interface wire without using any other supporting circuitry. Market research firm Yole Development (Lyon, France) puts the silicon microphone market last year at nearly 100 million units and predicts it will grow to 800 million units by 2010. Most of those, today, are analog MEMS microphones made for analog cell phones by Knowles Electronics LLC (Itasca, Ill.) and Sonion MEMS A/S (Roskilde, Denmark). In contrast, Akustica's silicon microphone has the analog-to-digital converter on the same chip, greatly simplifying integration into notebook PCs and other digital devices, such as PDAs, Bluetooth headsets and the increasing number of ports for voice-over-Internet Protocol (VoIP).
Monday, May 22, 2006
The Department of Energy has begun funding solutions to the engineering and infrastructure problems that must be solved before widespread commercialization of current photovoltaic technologies can become a reality. Called the Solar America Initiative, the 2007 DOE Budget set aside $148 million to accelerate the development of photovoltaic cells ranging from those made from monocrystalline, polycrystalline and amorphous silicon structures, as well as those based on thin films, organic polymers and quantum wells. The U.S. Department of Energy has issued a Notice of Program Interest to the industry, universities and other potential partners to help plan topics, program phases, technologies and procurement strategies to meet its goal. To start, Solar America will try to see what obstacles remain to commercialization, then enlist EEs and others to solve those problems. The program aims to develop multiple competing solar cell technologies by 2015 to provide electricity at a cost per kilowatt-hour that equals or exceeds what the grid offers.
Humanoid robots seized the spotlight at the IEEE's International Conference on Robotics and Automation here last week. All told, more than 1,200 engineers explored all the angles and scales of robots in upwards of 750 sessions covering everything from nanobots to full-sized robotic automobiles. But humanoid robots dominated a host of sessions at the Disney World Hilton, ranging from pure theoretical studies to end-user applications. In the latter category was a report by Waseda University (Tokyo) and Kanagawa University (Yokohama, Japan) that described a new robot designed to help senior citizens walk. If a robot bumps into something or is pushed from behind, say researchers at the University of Tokyo and City University of Hong Kong, they'll need a special algorithm to maintain stability. The researchers used video cameras and force plates to capture human responses to sudden disturbances, then extracted the parameters relevant to their solution. If all that "walking" worked up an appetite in Orlando, one of the more realistic humanoids, designed by the University of Tokyo, aims at conquering one of the most ubiquitous tasks facing any human: cooking meals.
Wednesday, May 17, 2006
While enabling better robots, biorobotics are also encouraging engineers to become neuroscientists, an expert told the IEEE's International Conference on Robotics and Automation. Keynote speaker Paolo Dario's team is validating new principles which integrate "bio-inspired" control and learning strategies with human/robot interfaces and mechanisms. They are also pursuing biomechatronics, or prosthetics, technical aids for physical rehabilitation and humanoid robots for assisting the elderly. For humanoid robotics applications, the new paradigm includes three computer models running simultaneously: a model of the world, a model of the human and a model of their interaction. The engineer/scientist first studies biological systems and formulates hypothesizes for how it succeeds. The resulting robot mimics the hypothesized procedures. Once the robot is debugged, biological systems are reevaluated to determine where a model went wrong and a new hypothesis is developed for correcting errors. Finally, the robot is rebuilt. Dario predicted that robotic surgery would benefit from biorobotic advances. Robo-surgery is designed to "steady the hand" of surgeons, and has progressed to delicate neurological procedures that are nearly impossible to perform without robotic assistance.
Biorobotics are also enabling new procedures that would be impossible to perform manually.
Biorobotics are also enabling new procedures that would be impossible to perform manually.
Posted by R. Colin Johnson at 7:04 AM
Monday, May 15, 2006
A carbon-nanotube-based thermal material has been crafted by researchers at Purdue University to transfer heat away from the densely packed transistors that are increasingly being crammed onto silicon chips. The researchers claim that the material transfers heat away from chips to any heat sink faster than the liquid-cooled method used by many of today's manufacturers. Heat sinks traditionally use metal fins to dissipate heat into the air. Even liquid-cooling fins, which circulate water through their inside channels to an externally cooled reservoir, still need to transfer the heat from the silicon chip to the heat sink. Ordinarily, an electrical insulator like mica, which nevertheless conducts heat, is used between the silicon chip and the heat sink. A thermal-transfer paste is applied to both sides of the mica before it is inserted between the chip and heat sink. The Purdue researchers contend that a carbon nanotube can transfer heat from the chip through the mica and to the sink more that three times more efficiently than paste.
Wednesday, May 10, 2006
A virtual reality installation sporting 100 million pixels is being touted as offering the world's highest resolution, and could aid medical and military research. The $4 million upgrade to Iowa State University's "C6" VR room will employ 24 Sony digital projectors to back-illuminate all four walls, floor and celling of the installation. Operators of the C6 room claimed it was the highest resolution VR installation when it was first unveiled in 2000. Since then, other VR rooms have been built with higher resolution, including a five-sided room recently installed by Fakespace Systems Inc. (Marshalltown, Iowa) and at the at Los Alamos National Laboratories' Strategic Computing Complex. Fakespace worked with Iowa State to upgrade its current C6 installation to regain the highest resolution: 100 million pixels compared to 43 million pixels at Los Alamos. The six-sided10- by 10- by 10-foot room back-projects 3D computer- generated scenes on walls, floor and ceiling. The images will be generated by a Hewlett-Packard computer with 96 parallel graphics processing units feeding the 24 digital projectors, plus an eight-channel 3D audio system and an ultrasonic motion-tracking system that changes the scene as a user turns his head.
Posted by R. Colin Johnson at 1:47 PM
Monday, May 08, 2006
IBM Corp. has found a way to electrically control the deposition rate of materials--the ink--from a dip-pen lithography system without lifting it from the substrate on which it is writing, thereby enabling molecular-scale nanolithography. Dip-pen lithography harnesses an atomic-force microscope (AFM) to ink virtually any chemical compound onto a substrate with nanometer control. Unfortunately, there was no way to control the deposition rate, because the molecules were deposited on a surface by diffusion--like a quill pen. The only thing that could be controlled was the speed at which the tip was scanning, and the only way to stop and start deposition was to lift and touch the pen to the substrate--a lengthy and error-prone procedure. IBM's trick was to add a reservoir to the AFM's tip at the place where it connects to a cantilever. Thus, the new cone-shaped tip directly ties into a material reservoir that can convey molecules up or down to a substrate with an electric field of a million volts per meter. By changing the strength and duration of the field, IBM has demonstrated millisecond-level control of deposition--a thousandfold faster than today's best methods. Like all dip-pen approaches, IBM's electronically controlled, direct-writing method uses AFM positioning accuracy to define complex patterns in a variety of materials with features down to 10 nm. That's five times smaller than today's e-beam lithography equipment and 10 times smaller than photolithography. The twist lies in adding control by an electric field, and in setting up the right conditions to make that work. Besides use in nanoscale lithography for electronic circuits, IBM predicts the method will enable nanoscale-size microfluidic devices, such as those that perform electrophoresis assays for everything from DNA fingerprinting to routine blood tests.
U.S. airports have invested billions in security since the 9/11 terrorist attacks. Still, the Government Accountability Office managed to sneak bomb-making components onto planes at 21 U.S. airports--every one it tested--over a recent four-month period. Now, an Israeli technology called CarrySafe has been licensed to a U.S. company that insists it could have detected those bomb-making components with 100 percent accuracy. In the security trial, conducted from last October until January, GAO investigators were able to smuggle explosives past screeners in their carry-on luggage in 21 out of the 21 U.S. airports. TraceGuard Technologies Inc. (New York), says its CarrySafe would have detected traces from every one of those carry-on bags. CarrySafe is a retrofit that collects traces of explosives that it passes to existing analysis equipment. Instead of manually swabbing a bag and putting the swab into an analyzer, hoping the single swabbed spot had residue on it, CarrySafe automatically collects residue from every part of the luggage. Originally designed to screen air cargo, CarrySafe wraps an active membrane around bags to detect trace amounts of explosives TraceTrack Technology Ltd. (Tel Aviv, Israel) has developed the technology for seven years, then last year licensed it to TraceGuard Technologies Inc., a U.S. corporation. The Israeli Security Agency is certifying CarrySafe for use in Israeli airports, and the U.S. Transportation Security Administration is expected to follow suit with certification in early 2007 for use in U.S. airports.
Monday, May 01, 2006
The first nanoscale piezoelectric generator, which could one day use environmental motion to provide unlimited electricity for small devices, has been demonstrated by researchers in Georgia. For the demonstration, the researchers grew arrays of nanoscale zinc-oxide piezoelectric nanowires perpendicular to a sapphire substrate and coupled the material's piezoelectric and semiconducting properties. While the group has not yet created a batteryless device, it did use an atomic-force microscope (AFM) to demonstrate how mechanical motion of the arrays of piezoelectric semiconductors could initiate a charge cycle for future batteryless devices. While the demonstration shows that the piezoelectric nanogenerator remains years away from powering commercial devices, the talk focused on its great potential. Converting mechanical energy into electricity with nanoscale piezoelectric materials could provide the foundation for future wireless applications, the researchers suggested. Besides simplifying medical implants, piezoelectric nanogenerators could also power remote sensors or even recharge conventional batteries. For instance, the researchers envision soldiers in the field with nanogenerators built into their uniforms so that their normal body movements can automatically recharge their communication devices' batteries.