Non-linear electrical actuation and detection

A method and system is disclosed to detect and analyze an electric signal based on movement between an element and a counter electrode influenced by a nonlinear electric field produced by an electrical signal impressed between the element and counter electrode. Through detection of changes in the distance between the element and the counter electrode characteristics of the element and/or the environment of the element may be ascertained. Changes in the distance between the element and the counter electrode may be monitored based on changes in the value of capacitance between the element and counter electrode. The disclosed devices and methods may be employed to detect, for instance, presence of chemical/biological species in a sample or measure physical parameters of a sample such as pressure/acceleration, density, viscosity, magnetic force, temperature, and/or extremely small masses

Self-Assembled Recyclable Hierarchical Bucky Aerogels

We describe a simple method for the scalable synthesis of three-dimensional, elastic, and recyclable multi-wall carbon nanotube (MWCNT) based light weight (density <1 g cm^(−3)) bucky-aerogels (BAGs) that are capable of efficiently absorbing non-polar solvents and separating oil-in-water emulsions. Our facile synthesis involves the self-assembly of MWCNTs and carbon fibers into a multi-layered, highly porous, and hierarchical structure that can be easily flexed, compressed, or burnt without any noticeable changes in its structure and absorption capacity. The BAG surface absorbs non-polar solvents efficiently up to ≈20 times its own weight due to its superhydrophobic nature arising from the presence of MWCNTs. Furthermore, BAGs exhibit excellent resilience to impact by recovering more than 70% of the deformation. The energy dissipated by BAGs at 80% compressive strain is in the order of 500 kJ m^(−3), which is nearly 50 times more than the energy dissipated by commercial foams with similar densities

Physics Classical and Modern

1093 tr. ; 26 cm

Physics classical and modern

xx, 1093 p. : ill.; 25 cm

Physics: classical and modern

xxii+1147hlm.;29c

Origin of FM Ordering in Pristine Micro- and Nanostructured ZnO

An unexpected presence of ferromagnetic (FM) ordering in nanostructured nonmagnetic metal oxides has been reported previously. Though this property was attributed to the presence of defects, systematic exptl. and theor. studies to pinpoint its origin and mechanism are lacking. While it is widely believed that oxygen vacancies are responsible for FM ordering, surprisingly we find that annealing as-prepd. samples at low temp. (high temp.) in flowing oxygen actually enhances (diminishes) the FM ordering. For these reasons, we have prepd., annealed in different environments, and measured the ensuing magnetization in micrometer and nanoscale ZnO with varying crystallinity. We further find from our magnetization measurements and ab initio calcns. that a range of magnetic properties in ZnO can result, depending on the sample prepn. and annealing conditions. For example, within the same ZnO sample we have obsd. ferro- to para- and diamagnetic responses depending on the annealing conditions. We also explored the effects of surface states on the magnetic behavior of nanoscale ZnO through detailed calcns