Effect of carbon/noncarbon addition on hydrogen storage behaviors of magnesium hydride

Various Mg/carbon and Mg/noncarbon composite systems were prepared by mechanical milling and their hydrogen storage behaviors were investigated. It was found that all the carbon additives exhibited prominent advantage over the noncarbon additives, such as BN nanotubes (BNNTs) or asbestos in improving the hydrogen capacity and dehydriding/hydriding kinetics of Mg. And among the various carbon additives, purified single-walled carbon nanotubes (SWNTs) exhibited the most prominent catalytic effect on the hydrogen storage properties of Mg. The hydrogen capacities of all Mg/C composites at 573 K reached more than 6.2 wt.% within 10 min, about 1.5 wt.% higher than that of pure MgH2 at the identical operation conditions. Under certain operation temperatures, H-absorption/desorption rates of Mg/carbon systems were over one order of magnitude higher than that of pure Mg. Furthermore, the starting temperature of the desorption reaction of MgH2 has been lowered to 60 K by adding SWNTs. On the basis of the hydrogen storage behavior and structure/phase investigations, the possible mechanism involved in the property improvement of Mg upon adding carbon materials was discussed. (c) 2005 Elsevier B.V. All rights reserved.

Addition of cue exposure to cognitive-behaviour therapy for alcohol misuse: a randomized trial with dysphoric drinkers

Aim To test whether addition of moderation-orientated cue exposure (CE) or CE after dysphoric mood induction ( emotional CE, ECE) improved outcomes above those from cognitive-behaviour therapy alone (CBT) in people who drank when dysphoric. Design Multi-site randomized controlled trial comparing CBT with CBT + CE and CBT + ECE. Setting Out-patient rooms in academic treatment units in Brisbane and Sydney, Australia. Participants People with alcohol misuse and problems controlling consumption when dysphoric (n = 163). Those with current major depressive episode were excluded. Intervention Eight weekly 75-minute sessions of individual treatment for alcohol problems were given to all participants, with CBT elements held constant across conditions. From session 2, CBT + CE participants resisted drinking while exposed to alcohol cues, with two priming doses of their preferred beverage being given in some sessions. After an initial CE session, CBT + ECE participants recalled negative experiences before undertaking CE, to provide exposure to emotional cues of personal relevance. Measurements Alcohol consumption, related problems, alcohol expectancies, self-efficacy and depression. Results Average improvements were highly significant across conditions, with acceptable maintenance of effects over 12 months. Both treatment retention and effects on alcohol consumption were progressively weaker in CBT + CE and CBT + ECE than in CBT alone. Changes in alcohol dependence and depression did not differ across conditions. Conclusions These data do not indicate that addition of clinic-based CE to standard CBT improves outcomes. A different approach to the management of craving may be required.

Effects of solids concentration, pH and carbon addition on the production rate and composition of volatile fatty acids in prefermenters using primary sewage sludge

Increasing evidence is emerging that the performance of enhanced biological phosphorus removal (EBPR) systems relies on not only the total amount but also the composition of volatile fatty acids (VFAs). Domestic wastewater often contains limited amounts of VFAs with acetic acid typically being the dominating species. Consequently, prefermenters are often employed to generate additional VFAs to meet the demand for carbon by EBPR and/or denitrification processes. Limited knowledge is currently available on the effects of operational conditions on the production rate and composition of VFAs in prefermenters. In this study, a series of controlled batch experiments were conducted with sludge from a full-scale prefermenter to determine the impact of solids concentration, pH and addition of molasses on prefermentation processes. It was found that an increase in solids concentration enhanced total VFA production with an increased propionic acid fraction. The optimal pH for prefermentation was in the range of 6-7 with significant productivity loss when pH was below 5.5. Molasses addition significantly increased the production of VFAs particularly the propionic acid. However, the fermentation rate was likely limited by the biological activity of the sludge rather than by the amount of molasses added.

The effect of Cu addition and milling contaminations on the microstructure evolution of ball milled Al-Pb alloy during sintering

Al-10 wt.%Pb and Al-10 wt.%Pb-x wt.%Cu (x = 0-7.0) bulk alloys were prepared by sintering the mechanically alloyed powders at various temperatures. The microstructure changes of the as consolidated powders in the course of sintering were analyzed by differential scanning calorimetry, scanning electron microscopy, X-ray diffraction analysis and transmission electron microscopy. It has been found that, with respect to the Al-10 wt.%Pb-x wt.%Cu alloy, CuAl2 and Cu9Al4 phases formed in the milling process, and the amount of CuAl2 phase increased while the Cu9Al4 phase disappeared gradually in the sintering process. In both Al-10 wt.%Pb and Al-10 wt.%Pb-x wt.%Cu alloys, the sintering process results in the coarsening of Pb phase and the growth rate of Pb phase fulfills the Lifshitz-Slyozov-Wagner equation even though the size of the Pb phase was in nanometer range. The Pb particle exhibits cuboctahedral morphology and has a cubic to cubic orientation relationship with the Al matrix. The addition of Cu strongly depressed the growth rate of Pb. Contamination induced by milling has apparent influence on the microstructure of the sintered alloys. Al7Cu2Fe and aluminium oxide phases were identified in the sintered alloys. The cuboctahedral morphology of Pb particles was broken up by the presence of the oxide phase. (c) 2006 Elsevier B.V. All rights reserved.

Peptide conjugate hydrogelators

Molecular gelators are currently receiving a great deal of attention. These are small molecules which, under the appropriate conditions, assemble in solution to, in the majority of cases, give long fibrillar structures which entangle to form a three-dimensional network. This immobilises the solvent, resulting in a gel. Such gelators have potential application in a number of important areas from drug delivery to tissue engineering. Recently, the use of peptide-conjugates has become prevalent with oligopeptides (from as short as two amino acids in length) conjugated to a polymer, alkyl chain or aromatic group such as naphthalene or fluorenylmethoxycarbonyl (Fmoc) being shown to be effective molecular gelators. The field of gelation is extremely large; here we focus our attention on the use of these peptide-conjugates as molecular hydrogelators.

Addition agent behaviour in acid tin plating

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT

An analysis of progressive addition spectacles lens design by the use of interferometry

Progressive addition spectacle lenses (PALs) have now become the method of choice for many presbyopic individuals to alleviate the visual problems of middle-age. Such lenses are difficult to assess and characterise because of their lack of discrete geographical locators of their key features. A review of the literature (mostly patents) describing the different designs of these lenses indicates the range of approaches to solving the visual problem of presbyopia. However, very little is published about the comparative optical performance of these lenses. A method is described here based on interferometry for the assessment of PALs, with a comparison of measurements made on an automatic focimeter. The relative merits of these techniques are discussed. Although the measurements are comparable, it is considered that the interferometry method is more readily automated, and would be ultimately capable of producing a more rapid result.