Molecular Sieve Silica (MSS) Membranes for Gas Separation and Reaction Processes

Weakly branched silica films formed by the two-step sol-gel process allow for the formation of high selectivity membranes for gas separation. 29Si NMR and gas permeation showed that reduced crosslinking leads to He/CH4 selectivity improvement from 300 to 1000. Applied in membrane reactor for cyclohexane conversion to benzene, conversions were achieved at 14 fold higher than a conventional reactor at 250°C. Hydrothermal stability studies showed that carbon templating of silica is required for hydrothermally stable membranes. From our work it was shown that with correct application of chemistry, practical membrane systems can be built to suit gas separation (e. g. hydrogen fuel) and reactor systems.

On the use of trace additions of Sn to enhance sintered 2xxx series Al powder alloys

The mechanical properties of a typical sintered aluminium alloy (Al-4.4Cu-0.8Si-0.5Mg) have been improved by the simultaneous use of trace additions of Sn, high sintering temperatures and modified heat treatments. Tin increases densification, but the Sn concentration is limited to less than or equal to 0.1wt% because incipient melting occurs during solution treatment at higher Sn levels. A sintering temperature of 620 degrees C increases the liquid volume over that formed at the conventional 590 degrees C sintering temperature. However, the higher sintering temperature results in the formation of an embrittling phase which can be eliminated if solution treatment is incorporated into the sintering cycle (a modified TS heat treatment). These conditions produce a tensile strength of 375 MPa, an increase of nearly 20% over the unmodified alloy. (C) 1999 Elsevier Science S.A. All rights reserved.

Quantum controlled-NOT gate with 'hot' trapped ions

We present a novel method of performing quantum logic gates in trapped ion quantum computers which does not require the ions to be cooled down to the ground state of their vibrational modes, thereby avoiding one of the principal experimental difficulties encountered in realizing this technology. Our scheme employs adiabatic passages and a phase shift conditional on the phonon number state.

Determination of mechanical properties of PECVD silicon nitride thin films for tunable MEMS Fabry-Pérot optical filters

This paper reports an investigation on techniques for determining elastic modulus and intrinsic stress gradient in plasma-enhanced chemical vapor deposition (PECVD) silicon nitride thin films. The elastic property of the silicon nitride thin films was determined using the nanoindentation method on silicon nitride/silicon bilayer systems. A simple empirical formula was developed to deconvolute the film elastic modulus. The intrinsic stress gradient in the films was determined by using micrometric cantilever beams, cross-membrane structures and mechanical simulation. The deflections of the silicon nitride thin film cantilever beams and cross-membranes caused by in-thickness stress gradients were measured using optical interference microscopy. Finite-element beam models were built to compute the deflection induced by the stress gradient. Matching the deflection computed under a given gradient with that measured experimentally on fabricated samples allows the stress gradient of the PECVD silicon nitride thin films introduced from the fabrication process to be evaluated.

A study on stress corrosion cracking and hydrogen embrittlement of AZ31 magnesium alloy

The stress corrosion cracking (SCC) behavior and pre-exposure embrittlement of AZ31 magnesium alloy have been studied by slow strain rate tensile (SSRT) tests in this paper. It is showed that AZ31 sheet material is susceptible to SCC in distilled water, ASTM D1.387 solution, 0.01 M NaCl and 0.1 M NaCl solution. The AZ31 magnesium alloy also becomes embrittled if pre-exposed to 0.01 M NaCl solution prior to tensile testing. The degree of embrittlement increased with increasing the pre-exposure time, It is proposed that both the pre-exposure embrittlement and SCC were due to hydrogen which reduces the cohesive strength. i,e,. hydrogen embrittlement, (c) 2005 Elsevier B.V. All rights reserved.

Molecular Sieve Silica Membranes

The Encyclopedia of Nanoscience and NanotechnologyTM is the world's first encyclopedia ever published in the field of nanotechnology. The 10-volume Encyclopedia is an unprecedented single reference source that provides an ideal introduction and overview of recent advances and emerging new aspects of nanotechnology, spanning from science to engineering to medicine. Although there are many books/handbooks and journals focused on nanotechnology, no encyclopedic reference work has been published as of today. The Encyclopedia fills this gap to provide basic information on all fundamental and applied aspects of nanotechnology by drawing on two decades of pioneering research. It is the only scientific work of its kind since the beginning of the field of nanotechnology, bringing together core knowledge and the very latest advances. About 400 review chapters and hundreds of entries written by over 1,000 of the world's leading scientists. It is written for all audience levels, allowing non-scientists to understand the nanotechnology while providing up-to-date information to active scientists and experts in the field. This outstanding encyclopedia is an indispensable source for research professionals, technology investors and developers seeking the most up-to-date information on nanotechnology, among a wide range of disciplines, from science to engineering to medicine.

Hydrogen Storage by Carbon Nanotubes

Encyclopedia of Nanoscience and Nanotechnology® is the World's first encyclopedia ever published in the field of nanotechnology. The 10-volume Encyclopedia is an unprecedented single reference source that provides ideal introduction and overview of most recent advances and emerging new aspects of nanotechnology spanning from science to engineering to medicine. Although there are many books/handbook and journals focused on nanotechnology, no encyclopedic reference work has been published covering all aspects of nanoscale science and technology dealing with materials synthesis, processing, fabrication, probes, spectroscopy, physical properties, electronics, optics, mechanics, biotechnology, devices, etc. The Encyclopedia fills this gap to provide basic information on all fundamental and applied aspects of nanotechnology by drawing on two decades of pioneering research. It is the only scientific work of its kind since the beginning of the field of nanotechnology bringing together core knowledge and the very latest advances. It is written for all levels audience that allows non-scientists to understand the nanotechnology while providing up-to-date latest information to active scientists to experts in the field. This outstanding encyclopedia is an indispensable source for research professionals, technology investors and developers seeking the most up-to-date information on the nanotechnology among a wide range of disciplines from science to engineering to medicine.

An analysis of why telehealth systems in Australia have not always succeeded

Telehealth programmes are rather similar to humans in the way that they are planned, develop, grow and ultimately die or disappear. To achieve good life expectancy for a telehealth programme there appear to be three major needs: nurturing, which includes the provision of money, ideas, education, training and innovation; experience, which involves an integrated management process, the achievement of long and wide patterns of usage, the development of updated policies and procedures and the involvement of multiple disciplines; success, which involves evidence of outcomes, evaluation and research, and, most important, the sharing of information through scientific and popular press publications, and conferences and collaborations with internal and external groups. The future of telehealth in Australia is at a watershed. There are now a substantial number of programmes, and there has been a large amount of financial and human investment in telehealth around the nation. There is, however, no forum for national leadership, no national association and little support at federal government level.