Showing Spotlights 241 - 248 of 517 in category Fabrication Technologies and Devices (newest first):
The small particles in volcanic ash can damage jet aircraft engines. During jet engine operation, large amounts of air are sucked in. If this air contains ash particles, especially glass-rich silicate ash, they will melt in the jet turbine's operating temperature of 1400-1500C and subsequently fuse to the turbine blades. This will drive the finely tuned blades out-of-balance and could stall the engine. In today's jet engines, a thermal barrier coating (TBC) insulates metallic engine parts from the heat generated by the combustion process. If ingested ash melts onto this coating it will penetrate it and, upon cooling, the molten ash forms a brittle glass that flakes off, taking the coating with it. A team of researchers have now examined a new class of ceramic TBC that could offer jet engines special protection against volcanic ash damage in the future.
May 31st, 2011
Microfluidic chips have proven to be a breakthrough analytical technique that has rendered analysis of proteins a medical routine. The sensitivity limits of immunoassays have been enhanced to picomolar concentrations using monoclonal antibodies, new labeling techniques, and devices for signal transduction and acquisition. It is now possible to routinely determine levels of hormones, cancer markers, response to infection with bacteria and viruses, monitor the evolution of a disease and test for medication levels. In a new review article, researchers argue that the most promising opportunities of microfluidics for diagnostics reside in point-of-care applications because a number of unmet needs can be fulfilled by microfluidic devices due to their portability, short sample processing time, and flexibility.
May 17th, 2011
The potential use of antimicrobial surface coatings ranges from medicine, where medical device infection is associated with significant healthcare costs, to the construction industry and the food packaging industry. Thin films containing silver nanoparticles have been seen as promising candidate coatings. Silver is known as one of the oldest antimicrobial agents. Silver ions are thought to inhibit bacterial enzymes and bind to DNA. Silver nanomaterials have been used effectively against different bacteria, fungi and viruses. Using something like an advanced form of a rubber stamp, scientists have now developed a way to adhere an ultra-thin (just a few molecules thick) antibacterial coating to a wound. The "stamped" area shows bactericidal activity for at least 48 hours.
May 5th, 2011
Glues adhere to solid materials via a multitude of fundamental physical or chemical interactions. Either chemical reaction times or solvent evaporation rates determine the point in time, when this interaction sets in and fixes the object to be glued. Electric potential has been used to attract polymers continuously to an electrode surface and to toggle molecules between states for a molecular switch. If you wanted to create electric glue, you would need to be able to control the interaction of a polymer and an electrode surface reversibly, thus creating a nanoscale system with electrochemically controlled adhesion. A research team now describes how Coulomb forces between polymers and surfaces may be measured, controlled, and manipulated.
May 3rd, 2011
Ink-jet printing of metal nanoparticles for conductive metal patterns has attracted great interest as an alternative to expensive fabrication techniques like vapor deposition. The bulk of the research in this area focuses on printing metal nanoparticle suspensions (metallic ink) for metallization. Printing conductive features by metallic nanoparticle inks must be followed by an additional step of sintering, usually achieved by heating to elevated temperatures. In this step, the nanoparticles composing the pattern will coalesce to form a continuous electrical contact. In new work, researchers have now demonstrated a new conductive ink that won't require a post printing sintering step. It is achieved by the addition of a latent sintering agent that gets into action after the printing step. Once the solvent evaporates, the sintering agent concentration increases, leading to the spontaneous sintering of the nanoparticles.
Apr 18th, 2011
Printed electronics is one of the most important new enabling technologies. It will have a major impact on most business activities from publishing and security printing to healthcare, automotive, military and consumer packaged goods sectors. With recent advances, power and energy storage can be integrated into the printing process, making their potential applications even more ubiquitous. Currently, though, the more complex printed components that require a combination of different class of devices, still experience drawbacks in performance, cost, and large-scale manufacturability. Researchers have now succeeded in fabricating a multi-component sensor array by simple printing techniques - all components (polymer sensor array, organic transistors, electrochromic display) are integrated on the same flexible substrate.
Apr 13th, 2011
In order to find replacement materials for ITO, scientists have been working with carbon nanotubes, graphene, and other nanoscale materials such as nanowires. While many of these approaches work fine in the lab, upscaleability usually has been an issue. Researchers at Empa, the Swiss Federal Laboratories for Material Science and Technology, have now demonstrated another solution: they presented a transparent and flexible electrode based on a precision fabric with metal and polymer fibers woven into a mesh. The team demonstrated organic solar cells fabricated on their flexible precision fabrics as well as on conventional glass/ITO substrates and found very similar performance characteristics.
Apr 4th, 2011
The power conversion efficiency of solar cells made of conjugated polymer/nanorod nanocomposites can be maximized when the nanocomposites are aligned perpendicularly between two electrodes for effective exciton dissociation and transport. To realize this, external fields can be applied to induce the self-assembly/alignment. The challenge is how to assemble them over a large scale - current self-assembly studies of cadmium selenide nanorods in literature are limited to only a micrometer scale. New design approaches are therefore needed to solve this problem. Due to their intrinsic structural anisotropy, nanorods possess many unique properties that make them potentially better nanocrystals than quantum dots for photovoltaics and biomedical applications.
Mar 29th, 2011