Poisson's ratio describes the fundamental elasticity of any solid. Poisson's ratio has been a basic principle of engineering for more than 200 years as it allows engineers to identify how much a material can be compressed and stretched and how much pressure it will withstand, before it collapses. Materials with a negative Poisson's ratio are relatively rare and it has recently become popular in referring to them as metamaterials - a group of materials that attain interesting or extreme properties via structure rather than composition.
A theory analysis of energy / momentum conservation laws in a spatially confined coupled system of nearly free electrons and phonons hints that the absorption of electromagnetic waves by a metallic nano-object hosting longitudinal vibration modes may allow channeling the absorbed energy either into heat or into terahertz radiation, depending on the nano-objects' shape and size. This offers an explanation for the size selectivity of small nanoparticles in radio frequency hyperthermia, and suggests design for novel terahertz radiation sources.
There is an often-asked question: 'When are we finally going to start seeing nanotechnology products on the market?' As a matter of fact, the average home is already filled with products enhanced or reliant upon nanotechnology. In fact, there are several online repositories listing the more than 2,000 commercially available products that incorporate nanotechnology. The application of nanotechnology in some areas, such as batteries, microelectronics and sunscreens is relatively well known. Let's take a virtual tour through a home to see what else we can find.
Education has long been recognized as an important factor for growing the fields of nanoscience and nanotechnology and solidifying and expanding their roles in the global economy. Leading researchers from the field discuss innovative learning models that are being applied at the undergraduate level in order to train future leaders at the interface of engineering and management. They have a set of five recommendations to improve the current situation.
In order to make robots and robotic technology more human-like and more human-friendly, smart skin technology is a critical element that helps robots sense the world. These electronic or smart skins could help machines to accurately perceive the environment and better assist human owners. By applying the triboelectric effect and planar electrostatic induction, researchers for the first time have created a self-powered analogue smart skin.
The scaling up of nanomaterials in the broader context of materials science and engineering is the topic of a Perspective article, where the authors construct a roadmap for assembling nanoscale building blocks into bulk nanostructured materials, and define some of the critical challenges and goals. Two-dimenisonal sheets are uniquely well-suited in this roadmap for constructing dense, bulk-sized samples with scalable material performance or interesting emergent properties. But no matter what structures are used, when nanostructures with better-than-bulk material performances are used in bulk form, it is critical that those extraordinary nanoscale properties can be scaled to the macroscopic level.
In the past couple of decades, nickel-tungsten (Ni-W) amorphous and nanocrystalline materials have been drawing more and more research interest due to the superior mechanical properties such as high hardness, good mechanical performance, and excellent corrosion resistance. Striving to enhance the mechanical performance of Ni-W thin film alloys, researchers report how the annealing temperature will influence the microstructure evolution and the fracture properties of Ni-W alloys.
Here are the 10 most popular Nanowerk Nanotechnology Spotlight articles of 2015. This year, the list includes a quick and simple blood test to detect early-stage cancer; self-powered smart suits; nanomaterials for camouflage and stealth applications; nanotechnology energy applications; 3D-printing with graphene; fuzzy and Boolean logic gates based on DNA nanotechnology; a path towards self-powered electronic papers; a look at whether nanomedicine lhas ived up to its promise; smart materials that become 'alive' with living bacteria in supramolecular assemblies; and repair nanobots on damage patrol.