In 2007, we focused on the global climate, and as gas prices soared, more novel technologies emerged in the development of alternative fuel and power sources. Once again, electronics and computers became smaller, faster, and cheaper, thanks to advances in nano-engineering and alternative battery technologies. Homeland security continued to be a focus of research and development in new ways to protect ourselves and our soldiers. And a number of breakthroughs in the medical field brought the promise of revolutionary new diagnostic and treatment options.

Wireless Power Transfer

Researchers in the Department of Physics, Department of Electrical Engineering and Computer Science, and Institute for Soldier Nanotechnologies (ISN) at Massachusetts Institute of Technology (MIT) have demonstrated wireless power transfer. This breakthrough could mean that your cell phones, laptop computer, iPod, and other portable electronics could charge themselves without being plugged in. Some may not even need their batteries to operate.

The team lit a 60W light bulb from a power source seven feet away with no physical connection between the power source and the bulb. The MIT team refers to its concept as “WiTricity” (as in wireless electricity). WiTricity is based on using coupled resonant objects. Two resonant objects of the same resonant frequency tend to exchange energy efficiently, while interacting weakly with extraneous off-resonant objects. A child on a swing is a good example of this. A swing is a type of mechanical resonance, so only when the child pumps her legs at the natural frequency of the swing is she able to impart substantial energy.

The team explored a system of two electromagnetic resonators coupled mostly through their magnetic fields; they were able to identify the strongly coupled regime in this system, even when the distance between them was several times larger than the sizes of the resonant objects. This way, efficient power transfer was enabled. Magnetic coupling is suitable for everyday applications because most common materials interact only very weakly with magnetic fields, so interactions with extraneous environmental objects are suppressed even further.

WiTricity is rooted in such well-known laws of physics that it makes one wonder why no one thought of it before. But over the past several years, portable electronic devices have become widespread, all of which require batteries that need to be recharged often.

For more information on WiTricity, click here .

Technology Removes Viruses From Drinking Water

Pei Chiu (left), an associate professorin UD’s Department of Civil andEnvironmental Engineering, andYan Jin, a professor of environmentalsoil physics in UD’s plant and soilsciences department, have developedan inexpensive, nonchlorinebasedtechnology that can removeharmful microorganisms from drinkingwater, including viruses.

University of Delaware researchers have developed an inexpensive, nonchlorine-based technology that can remove harmful microorganisms, including 99.999% of viruses, from drinking water. It incorporates highly reactive iron in the filtering process to deliver a chemical “knock-out punch” to a host of pathogens, from E. coli to rotavirus. The technology could dramatically improve the safety of drinking water around the globe, particularly in developing countries.

Viruses are difficult to eliminate in drinking water using current methods because they are far smaller than bacteria, highly mobile, and resistant to chlorination, which is the dominant disinfection method used in the United States. By using elemental iron in the filtration process, the researchers were able to remove viral agents from drinking water at very high efficiencies. Of a quarter of a million particles going in, only a few were going out. The elemental or “zero-valent” iron (Fe) used in the technology is widely available as a byproduct of iron and steel production, and is inexpensive, currently costing less than 40 cents a pound. Viruses are either chemically inactivated by or irreversibly adsorbed to the iron, according to the scientists.

Besides helping to safeguard drinking water, the technology may have applications in agriculture. Integrated into the washwater system at a produce-packing house, it could help clean and safeguard fresh vegetables, particularly leafy greens like lettuce and spinach, as well as fruit. The Centre for Affordable Water and Sanitation Technology in Calgary, Canada, is exploring use of the technology in a portable water treatment unit.

For more information on the virus-removal technology, click here .

New Hope in Fight Against “Superbug” Infections

Late this year, several U.S. high school and college students died as a result of bacterial infections that were resistant to antibiotics. These “superbugs” survive and thrive in hospitals and patients, and doctors are helpless to fight them with current medications. A biomedical engineer at Boston University (BU) recently discovered a previously unknown chain of events occurring in bacteria when they are fed antibiotics.

The three classes of bactericidal antibiotics used today each target a different bacterial function: inhibiting DNA replication, blocking protein building, or halting construction of cell walls. But, BU research found the three distinct classes more alike than anyone realized, and the commonalities may be the bugs’ downfall.

BU researchers (from left) Michael Kohanski,Carrie Lawrence, Jim Collins, and Dan Dwyer.

The researchers discovered a common process, or pathway, that was triggered by all three types of antibiotics: excessive free radical production. Free radicals — such as hydroxyl or superoxide radicals — are molecules that carry a free, or unpaired, electron like a weapon, and damage DNA, proteins, lipids in the membrane, and just about anything else. This pathway, and resultant free radical overload, can cripple or kill bacteria, and in the future might be employed to help lower antibiotic doses, increase the vulnerability of resistant bacteria to drugs, or to develop new antibiotics. By inhibiting or blocking the bacterial defense mechanisms to hydroxyl radical damage, it is possible to potentiate or enhance the lethality of bactericidal antibiotics.

In addition to potentially making bacteria more vulnerable to current drugs, this finding may revitalize development of antibiotic drugs sidelined because of narrow differences between therapeutic and toxic doses. Such drugs might reenter the pipeline, if this pathway is exploited to lower the therapeutic dose, making formerly dangerous drugs safer.

For more information on this new pathway, click here .

Storing Power in a Sheet of Paper

Researchers at Rensselaer Polytechnic Institute have developed a new energy storage device that resembles a sheet of black paper. The nanoengineered battery is lightweight, ultra thin, flexible, and meets design and energy requirements of tomorrow’s gadgets, implantable medical equipment, and transportation vehicles. Along with its ability to function in temperatures up to 300°F and down to 100 below zero, the device is completely integrated and can be printed like paper. Another key feature is the capability to use human blood or sweat to help power the battery.

RPI’s flexible “paper” battery can be rolled,twisted, folded, or cut into a number ofshapes.

More than 90 percent of the device is made up of cellulose, the same plant cells used in newsprint, loose-leaf paper, lunch bags, and most other types of paper. The researchers infused the paper with aligned carbon nanotubes, which give the device its black color. The nanotubes act as electrodes and allow the storage devices to conduct electricity. The device can provide the long, steady power output comparable to a conventional battery, as well as a supercapacitor’s quick burst of high energy.

The device can be rolled, twisted, folded, or cut into a number of shapes with no loss of mechanical integrity or efficiency. The paper batteries can also be stacked, like a ream of printer paper, to boost the total power output. The components are molecularly attached to each other: the carbon nanotube print is embedded in the paper, and the electrolyte is soaked into the paper. The end result is a device that looks, feels, and weighs the same as paper.

The researchers used ionic liquid, essentially a liquid salt, as the battery’s electrolyte. Ionic liquid contains no water, which means there’s nothing in the batteries to freeze or evaporate.

Along with small handheld electronics, the paper batteries’ light weight could make them ideal for use in automobiles, aircraft, and boats. The paper also could be molded into different shapes, such as a car door. Paper is biocompatible, so the hybrid battery/supercapacitors have potential as power supplies for devices implanted in the body. The team printed paper batteries without adding any electrolytes, and demonstrated that naturally occurring electrolytes in human sweat, blood, and urine can be used to activate the battery device.

The team has filed a patent protecting the invention, and is working on ways to boost the efficiency of the batteries and supercapacitors.

For more information on the paper batteries, click here .

Electric Pulses Destroy Cancer Cells

California at Berkeley have developed a new minimally invasive method of treating cancer. Called irreversible electroporation (IRE), the process was invented by two engineers, Rafael V. Davalos of Virginia Tech and Boris Rubinsky of UC Berkeley. Electroporation is a phenomenon that increases the permeability of a cell from none, to a reversible opening, to an irreversible opening. With the latter, the cell will die. The researchers applied this irreversible concept to the targeting of cancer cells.

“IRE removes tumors by irreversibly opening tumor cells through a series of short, intense electric pulses from small electrodes placed in or around the body,” said Davalos. “This application creates permanent openings in the pores in the cells of the undesirable tissue. The openings eventually lead to the death of the cells without the use of potentially harmful chemotherapeutic drugs. We did not use any drugs, the cells were destroyed, and the vessel architecture was preserved.”

Rafael V. Davalos, co-inventor of the IREprocess of killing cancer cells with electricpulses.

Oncologists already use a variety of methods to destroy tumors using heat or freezing processes, but these current techniques can damage healthy tissue or leave malignant cells. The difference with IRE is the ability adjust the electrical current and reliably kill the targeted cells.

“IRE shows remarkable promise as a minimally invasive, inexpensive surgical technique to treat cancer. It has the advantages that it is easy to apply, is not affected by local blood flow, and can be monitored and controlled using electrical impedance tomography,” Davalos explained.

For more information on the cancer treatment process, click here .

Self-Healing Materials Mimic Human Skin

The next generation of self-healing materials has been invented by researchers at the University of Illinois. The material mimics human skin by healing itself time after time. The new materials rely upon embedded, 3D microvascular networks that emulate biological circulatory systems. In the same manner that a cut in the skin triggers blood flow to promote healing, a crack in the new materials will trigger the flow of healing agent to repair the damage.

Inventors of the self-healing materials(clockwise from front): Katie Toohey,Nancy Sottos, Jennifer Lewis, Scott White,and Jeffrey Moore. (Photo by L. BrianStauffer)

To create the self-healing materials, the researchers built a scaffold using a robotic deposition process called direct-write assembly. The process employs a concentrated polymeric ink, dispensed as a continuous filament, to fabricate a 3D structure, layer by layer. Once the scaffold has been produced, it is surrounded with an epoxy resin. After curing, the resin is heated and the ink, which liquefies, is extracted, leaving behind a substrate with a network of interlocking microchannels. In the final steps, the researchers deposited a brittle epoxy coating on top of the substrate, and filled the network with a liquid healing agent.

In tests, the coating and substrate were bent until a crack formed in the coating. The crack propagated through the coating until it encountered one of the fluid-filled “capillaries” at the interface of the coating and substrate. The healing agent moved from the capillary into the crack, where it interacted with catalyst particles. If the crack reopened under additional stress, the healing cycle was repeated.

Currently, the material can heal cracks in the epoxy coating — analogous to small cuts in skin. The researchers’ next step is to extend the design to where the network can heal “lacerations” that extend into the material’s substrate.

For more information on the self-healing materials, click here .

New Screening Device Detects Toxic Material in Concealed Packaging

Sandia National Laboratories has developed screening devices that identify hazardous and toxic materials, even if concealed by clothing and packaging. Working in the underutilized terahertz (THz) portion of the electromagnetic spectrum that lies between microwaves and infrared, a team of Sandia scientists is building an integrated, miniaturized terahertz transmitter- receiver (transceiver). The technology can be used to scan for items such as concealed weapons or materials, explosives, and weapons of mass destruction. It also has applications in advanced communication systems and high-resolution radar.

The miniature toxic material screening device shown next to a dime to illustrateits size.

Over the past three years, the terahertz situation has changed due to the development of terahertz quantum cascade lasers. These tiny lasers are semiconductor sources of terahertz radiation capable of output powers in excess of 100 mW. Previously, such powers could only be obtained by molecular gas lasers occupying cubic meters and weighing more than 100 kg, or free electron lasers weighing tons and occupying entire buildings. Quantum cascade laser-based systems can be less than the size of a baseball and powered from a ninevolt battery.

The researchers expect to have a working prototype capable of detecting materials and chemicals by reading distinctive molecular spectral “signatures.” Most materials and chemicals have their own unique terahertz spectral signatures, so a terahertz transceiver system would be able to measure, for example, the signature of a gas and determine what it is.

In addition to monitoring for concealed hazardous materials, a terahertz system can be used to monitor the air for toxic materials. Using air sampling technology developed at Sandia and other locations, hazardous vapors can be preconcentrated. Shining light from the quantum cascade laser through the concentrated sample provides a direct identification of the vapor. This technology can be used in conjunction with existing mass spectrometer-based systems to reduce false identifications.

For more information on the toxic material screening device, click here .


NASA Tech Briefs Magazine

This article first appeared in the December, 2007 issue of NASA Tech Briefs Magazine.

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