Influence of joint detail on the flexural/torsional interaction of thin-walled structures

For a structure formed from two thin-walled open members connected at 90°, torsion applied to one member can result in torsion as well as flexure in the second member, with the magnitude and direction of this torsion as well as flexure in the second member being determined by the type of joint used. Conventional structural analysis would normally assume the presence of only flexure in the second member. The results from a finite element study of structures formed from thin-walled channel sections connected by box, mitre and stiffened mitre joints is presented and an explanation for the behaviour of the different joint types is given. It is shown that for the box joint the warping deformation of the loaded member is the dominant factor in determining the magnitude and direction of the twisting of the second member, whilst this is determined for the stiffened mitre joint primarily by the St Venant rotation deformation of the loaded member. For the unstiffened joint it is shown that the warping and St Venant rotation deformation effects tend to cancel each other out.     

Effects of growth with ethanol on fermentation and membrane fluidity of Saccharomyces cerevisiae

Saccharomyces cerevisiae HSc was grown with ethanol at concentrations up to 10% (v/v). The immediate effects of additions of externally added ethanol on CO₂ production and O₂ consumption of washed organisms were studied by stopped-flow membrane inlet quadrupole mass spectrometry. Fermentative activities of organisms grown with ethanol (0–5% v/v) showed similar sensitivities to inhibition by ethanol, whereas those grown with 10% (v/v) ethanol had become protected and were markedly less sensitive. The fluidity of subcellular membrane fractions was measured by determination of the temperature dependence of the rotational order parameter of the spin label 5-doxyl stearic acid (free radical) by electron spin resonance. Mitochondria prepared from yeasts grown with 0, 7 and 9% (v/v) ethanol showed similar overall fluidity, although differences in temperature-dependent behaviour indicate altered lipid composition or lateral phase separations. On the other hand the microsomal fraction from organisms grown with 9% ethanol showed a remarkable increase in fluidity. These data suggest that the protective effects of growth with ethanol near the limit of tolerance on fermentative activities may arise from altered plasma membrane fluidity properties.     

Cocaine transiently impairs maternal behavior in the rat.

This paradigm distinguished between two hypotheses not previously directly addressed. Do repeated exposures to cocaine at critical times during pregnancy, when the neural mechanisms that support maternal behavior are being readied, alter some fundamental neural underpinning of maternal behavior in rats? Alternatively, does cocaine alter maternal behavior only when circulating? During the 4 hr after cocaine injection (20 or 40 mg/kg), there were significant deficits in maternal behavior. In contrast, 16 hr after cocaine injection, drug-injected females, in which plasma cocaine had fallen to nondetectable levels, showed the normal maternal behavior of saline-injected controls. This pattern of impaired maternal behavior after cocaine injection, followed by normal behavior as blood levels returned to zero, was replicated over 8 days. It was concluded that cocaine impairs maternal behavior only when circulating and does not have a residual effect in the transiently drug-free, chronically drug-treated dam. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An evaluation of possible EU air transport emissions trading scheme allocation methods

The European Commission has been requested by member states to study the incorporation of air transport into their existing emissions trading scheme (ETS). Only CO₂ is to be included, at least initially.     

Multiple levels of cell by cell Adaptive Mesh Refinement in the Lagrangian step of the ALE code CORVUS

A multi-level cell by cell Adaptive Mesh Refinement (AMR) hydrodynamics capability has been developed for the Lagrangian step of the 2D Arbitrary Lagrangian Eulerian (ALE) code CORVUS. Connectivity arrays are used rather than a hierarchical data structure. We solve only on the dynamic unstructured mesh rather than on every level of a refinement hierarchy. The strength, artificial viscosity, slide and programmed burn methods have been generalised to work with AMR. Results are presented for a range of Lagrangian test problems.     

Cordierite glass-ceramics-effect of TiO2 and ZrO2 content on phase sequence during heat treatment

A series of glasses of stoichiometric composition with varying proportions of TiO₂ and/or ZrO₂ as nucleating agent have been studied to examine the effect of nucleation addition on the sequence of crystallization and transformation to the stable phase, cordierite. It is shown that TiO₂ is the most effective nucleating agent and that if large amounts of ZrO₂ are substituted for TiO₂ cristobalite forms as an intermediate phase and is associated with rapid volume changes and consequently with weak porous products. Substitution of ZrO₂ for TiO₂ also causes other changes in phase development, especially in the relative proportions of -quartz solid solution and magnesian petalite produced during the early stages of crystallization. The use of a combination of experimental techniques (dilatometry, DTA, X-ray diffraction and electron microscopy) has proved most effective in studying phase development and the relationship between processing characteristics and composition.     

A new device for the treatment of female stress urinary incontinence

Treatment for stress urinary incontinence (SUI) comprises a broad range of possible interventions. Non-surgical options include absorbent pads, vaginal weights and cones, biofeedback and minimally invasive techniques such as urethral bulking agents (UBAs). Surgical interventions range in complexity from sling surgery and suspension techniques to more major surgeries such as burch colposuspension. Each option has its challenges and limitations. This paper will focus on UBAs, which are implantable materials whose purpose is to augment urethral tissue function and restore continence. The characteristics required of such materials, and the challenges to be overcome when incorporating them in a successful product design, will be described and discussed. Particular attention will be given to the latest developments in the administration of polydimethylsiloxane elastomer UBA.     

Characterization of a High-Temperature Thermal Conductivity Reference Material

The development of thermal conductivity reference materials for high-temperature insulation consists of three stages: provisional assessment of candidate reference materials, detailed assessment of candidate reference material(s) and corresponding inter-laboratory comparisons. This paper describes the detailed characterization of a candidate high-temperature thermal conductivity reference material, a high-density calcium silicate (HDCaSi-N). The selection criteria, assessments of uniformity and stability, the thermal expansion behavior and their effects on the thermal conductivity reference specimens are presented in the paper. The uniformity assessments include the thermal expansion variation in orthogonal orientations and different locations and from different boards, as well as thermal conductivity variation within the batch of the specimens. The dimensional stability assessment in terms of thermal expansion and the short-term stability in terms of thermal conductivity are also presented.     

Degradation of Lignocellulosic Materials and Its Prevention

Lignocellulose-based materials, such as wood, have long been used for structural applications, but their inherent susceptibility to biological and physical degradation sometimes limits their use and leads to early replacement. Concerns about the contributions about the environmental impacts of all materials have sparked renewed interest in using renewable materials in structural applications. An important aspect of any increased use of these materials will be enhancing their durability. This review examines the inherent susceptibility of lignocellulose-based materials to degradation, using wood as the primary example, and then it outlines the research underway to improve these properties.     

Best estimate of the magnitude of mortality due to occupational exposure to hazardous substances

OBJECTIVES: With a proportionate attributable risk approach, to estimate the magnitude of premature mortality induced by exposure to hazardous substances in the Australian workforce. METHODS: Estimates of the magnitude of mortality induced by exposure to hazardous substances in the Australian work-force were calculated by the proportionate attributable risk approach after careful consideration of options for methodological refinements. The main data sources used were unit mortality datasets (individual deidentified death records), and tabulations when these were unavailable. RESULTS: The estimated number of deaths that occurred in Australia each year from occupational exposure to hazardous substances was 2290; 78% of these were men. The rate of mortality attributable to occupational exposure to hazardous substances was three to four times greater in male workers than in female workers. Male (productive) person-years of life lost (PYLL) were generally eight times higher than female PYLL. Cancer was the prime cause of death, followed by renal, cardiovascular, neurological, and chronic respiratory disease. Acute toxic episodes accounted for a small proportion of mortality but yielded a much larger proportion of PYLL, reflecting the relatively young ages of those who experienced fatal effects. CONCLUSIONS: Although national estimates of the proportions of mortality attributable to occupational exposure to hazardous substances seemed to be validly derived, uncertainties remain associated with the lack of an empirical basis for derivation of proportionate risk fractions used in the calculations. The finding of an appreciable burden of mortality that is attributable to past occupational exposure to hazardous substances emphasises the necessity for occupational health and safety authorities to measure and reduce worksite exposures. There is also an incentive to encourage the construction of appropriately designed cohort studies across industries and occupational groupings so that, ultimately, risk estimates may be directly calculated and applied to total workforce data for the definitive estimation of the magnitude of harm induced by occupational exposure to hazardous substances.