Showing Spotlights 921 - 928 of 2140 in category (newest first):
The huge economic impact of the corrosion of metallic structures is a very important issue for all modern societies. Estimates for the cost of corrosion degradation run to about 200 billion euros a year in Europe and over $270 billion a year in the U.S. The annual cost of corrosion consists of both direct costs and indirect costs. The direct costs are related to the costs of design, manufacturing, and construction in order to provide corrosion protection, and the indirect costs are concerned with corrosion-related inspection, maintenance and repairs. Researchers in Germany have now developed a novel and effective encapsulation system for metal protection against a wide range of biological and chemical aggressive agents.
Jan 20th, 2012
A University of Ulster laboratory has found a simple, low cost and environmentally friendly way to turn common graphite flakes into bulk amounts of either high quality graphene nanosheets or quantum dots. Such structures could lead to new nanoelectronics and energy conversion technologies. The scientists discovered a simple process, which is quicker and environmentally friendlier than currently established techniques for making high quality graphene nanosheets and quantum dots at an industrial scale. The most important attribute of the produced graphene nanosheets and quantum dots compared to those reported in the literature is that they are clean from any solvent contamination and possess a low concentration of oxygen, which is inherited from the starting graphite powder.
Jan 18th, 2012
Theoretical and experimental studies over the past few years have demonstrated that carbon nanotubes (CNTs) could exhibit novel and outstanding electromagnetic effects. Researchers have used this to fabricate various types of CNT nanocomposite materials for electromagnetic interference shielding, outperforming conventional shielding. In new work, scientists have now demonstrated the enhanced X-ray shielding of CNTs. Previously, scientists believed that X-ray attenuation - the gradual loss in intensity of X-rays as they travel through a medium - was determined by the atomic number of a material and that its structure didn't matter. What the team found, though, was that that the mass attenuation coefficient of CNTs was by 20-50% higher than that observed for highly oriented pyrolytic graphite and fullerenes.
Jan 16th, 2012
Heat has become one of the most critical issues in computer and semiconductor design. Three factors are playing the most important role in a microscale heat sink cooling system: the thermal conductivity of the material of the cooling fins; the heat exchange area of the cooling fins; and the convection between cooling fins and ambient. Carbon nanotubes satisfy the first two factors very well. They possess very high thermal conductivity and very high surface/volume ratio among other outstanding physical properties such as light, high current carrying capacity, excellent mechanical strength, etc. To reduce high temperatures, today's heat sinks are attached to the back of the chips to pull thermal energy away from the microprocessor and transfer it into the surrounding air. Researchers have now demonstrated the application of interface-enhanced CNTs as on-chip cooling fins in a microchannel heat sink.
Jan 13th, 2012
Repellents play an important role in protecting humans from insect bites. An effective and safe repellent is useful in reducing human-vector contact, and thereby helps in the interruption of vector-borne disease transmission - mosquito bites can cause causes diseases like dengue and malaria. There are two types of repellents - synthetic and natural. DEET and DEPA are two of the best studied and most common active ingredient in insect repellents. Researchers in India have developed a cream of microencapsulated DEPA with two natural biodegradable polysaccharides which increases the efficiency of mosquito repellency from 6 hours to 12 hours. No DEPA-based formulation with up to 12 hours of protection time has been reported so far.
Jan 12th, 2012
This article summarizes the progress, products outlook, advantages, and limitations of nanocomposites in the automotive industry. Polymer nanocomposites represent a new class of multiphase materials containing dispersion of nano-sized filler materials such as nanoparticles, nanoclays, nanotubes, nanofibers etc. within the polymer matrices. Owing to their nanoscale size features and very high surface-to-volume ratios, they possess unique combination of multifunctional properties not shared by their more conventional composite counterparts reinforced with micro-sized fillers. These multifunctional nanocomposites not only exhibit excellent mechanical properties, but also display outstanding combination of optical, electrical, thermal, magnetic and other physico-chemical properties.
Jan 11th, 2012
Nitric oxide (NO) is known to possess impressively broad antimicrobial activity due to both its inherent ability to inhibit growth and kill pathogens as well as its function as a potent immunostimulatory signaling molecule. Research data shows that NO is a potentially powerful therapeutic for serious skin and soft-tissue infections, including MRSA (methicillin-resistant S. aureus) infected wounds. However, as a highly reactive gas, NO has proven difficult to deliver in a convenient and cost effective therapeutic format. This limitation has largely precluded its routine use, even in hospital settings. In new work, researchers have now demonstrated the potential application of NO as an antimicrobial agent in the setting of skin and soft tissue infections.
Jan 4th, 2012
Vanadium dioxide (VO2) has long been recognized as a a material of significant technological interest for optics and electronics and a promising candidate for making 'smart' windows: it can transition from a transparent semiconductive state at low temperatures, allowing infrared radiation through, to an opaque metallic state at high temperatures, while still allowing visible light to get through. So far, VO2 hasn't been considered to be particularly suited for large-scale practical smart-window applications due to its low luminous transmittance and solar modulating ability. Researchers in China have now developed a process that can prepare VO2 thin-films with a controllable polymorph and morphology. Their results show that with increased porosity and decreased optical constants the performance of the VO2 films is enhanced, leading to a higher transmittance of visible light and improved solar modulating ability.
Dec 28th, 2011