Factors affecting the design and construction of Lamella suspen-dome systems

The suspen-dome system is a new structural form that has become popular in the construction of long-span roof structures. These domes are very slender and lightweight, their configuration is complicated, and hence sequential consideration in the structural design is needed. This paper focuses on these considerations, which include the method for designing cable prestress force, a simplified analysis method, and the estimation of buckling capacity. Buckling is one of the most important problems for dome structures. This paper presents the findings of an intensive buckling study of the Lamella suspen-dome system that takes geometric imperfection, asymmetric loading, rise-to-span ratio, and connection rigidity into consideration. Finally, suggested design and construction guidelines are given in the conclusion of this paper. (c) 2005 Elsevier Ltd. All rights reserved.

A Review of the Environmental and Health Effects of Termiticides under Australian Conditions

There exists a major cost issue as regards termite damage to wooden structures. A factor in this cost has been the increasing trend towards slab-on-ground construction. Current literature has been reviewed in relation to concerns about the possible public/environmental health consequences of the repeated use of termiticides in large quantities. The previous, current and projected future use patterns of termiticides are reviewed in the context of techniques appropriate for termite control and treatment priorities. The phasing out of organochlorine termiticides in Australia was undertaken to minimise impact of these substances on the environment and to a lesser extent on public health. These persistent chemicals were replaced by substances with high activity but relatively low persistence in the soil. There has also been an increase in the use of alternative methods (e.g. physical barriers) for the control of termites. The transition away from organochlorine termiticides has led to a realisation that significant information gaps exist with regard to replacement chemicals and other technologies. Although relatively persistent, the organochlorine chemicals have a limited lifespan in soils. Their concentrations are gradually attenuated by processes such as transport away from the point of application and biodegradation. Wooden structures originally treated with these substances will, with the passing of time, be at risk of termite infestation. The only available option is re-treatment with chemicals currently registered for termite control. Thus, there are likely to be substantial future increases associated with the cost of re-treatment and repairs of older slab-on-ground dwellings. More information is required on Australian termite biology, taxonomy and ecology. The risks of termite infestation need to be evaluated, both locally and nationally so that susceptible or high risk areas, structures and building types can be identified and preventive measures taken in terms of design and construction. Building regulations and designs need to be able to reduce or eliminate high-risk housing; and eliminate or reduce conditions that are attractive to termites and/or facilitate termite infestation.

The mental health country profile: Background, design and use of a systematic method of appraisal

This article describes the construction and use of a systematic structured method of mental health country situation appraisal, in order to help meet the need for conceptual tools to assist planners and policy makers develop and audit policy and implementation strategies. The tool encompasses the key domains of context, needs, resources, provisions and outcomes, and provides a framework for synthesizing key qualitative and quantitative information, flagging up gaps in knowledge, and for reviewing existing policies. It serves as an enabling tool to alert and inform policy makers, professionals and other key stakeholders about important issues which need to be considered in mental health policy development. It provides detailed country specific information in a systematic format, to facilitate global sharing of experiences of mental health reform and strategies between policy makers and other stakeholders. Lastly, it is designed to be a capacity building tool for local stakeholders to enhance situation appraisal, and multisectorial policy development and implementation.

Population pharmacokinetics and association between A77 1726 plasma concentrations and disease activity measures following administration of leflunomide to people with rheumatoid arthritis

Aims To investigate the concentration-effect relationship and pharmacokinetics of leflunomide in patients with rheumatoid arthritis (RA). Methods Data were collected from 23 RA patients on leflunomide therapy (as sole disease modifying antirheumatic drug (DMARD)) for at least 3 months. Main measures were A77 1726 (active metabolite of leflunomide) plasma concentrations and disease activity measures including pain, duration/intensity of morning stiffness, and SF-36 survey. A population estimate was sought for apparent clearance (CL/F ) and volume of distribution was fixed (0.155 l kg(-1)). Factors screened for influence on CL/F were weight, age, gender and estimated creatinine clearance. Results Significantly higher A77 1726 concentrations were seen in patients with less swollen joints and with higher SF-36 mental summary scores than in those with measures indicating more active disease (P < 0.05); concentration-effect trends were seen with five other disease activity measures. Statistical analysis of all disease activity measures showed that mean A77 1726 concentrations in groups with greater control of disease activity were significantly higher than those in whom the measures indicated less desirable control (P < 0.05). There was large between subject variability in the dose-concentration relationship. A steady-state infusion model best described the pharmacokinetic data. Inclusion of age as a covariate decreased interindividual variability (P < 0.01), but this would not be clinically important in terms of dosage changes. Final parameter estimate (% CV interindividual variability) for CL/F was 0.0184 l h(-1) (50%) (95% CI 0.0146, 0.0222). Residual (unexplained) variability (% CV) was 8.5%. Conclusions This study of leflunomide in patients using the drug clinically indicated a concentration-effect relationship. From our data, a plasma A77 1726 concentration of 50 mg l(-1) is more likely to indicate someone with less active disease than is a concentration around 30 mg l(-1). The marked variability in pharmacokinetics suggests a place for individualized dosing of leflunomide in RA therapy.

Using front-end and formative evaluation to design and test persuasive bird feeding warning signs

Wildlife feeding is a wide-spread and controversial practice that can pose serious threats to the safety of both wildlife and visitors. The design and effectiveness of warning signs in recreational areas varies considerably and is rarely the product of theoretical models or scientific research. This study uses front-end and formative evaluation to design and test the perceived effectiveness of warning signs relating to bird feeding. Stage One examined visitors' beliefs, attitudes and bird feeding behaviour and found significant differences between feeders and non-feeders. Stage Two involved designing and evaluating three signs that built on the beliefs, knowledge and mis/conceptions identified in Stage One. Respondents thought the sign that focused on the birds' health and safety would be the most persuasive, however, elements of the other two signs were also positively evaluated. The article concludes with recommendations for the wording of future bird feeding warning signs. (c) 2004 Elsevier Ltd. All rights reserved.

PhotoVoltaic DC-DC module integrated converter for novel cascaded and bypass grid connection topologies - design and optimisation

Grid connected PhotoVoltaic (PV) inverters fall into three broad categories — Central, String and Module Integrated Converers (MICs). MICs offer any avantaes in performance and flexibility, but are at a cost disadvantage. Two alternative novel approaches proposed by the author — cascaded dc-dc MICs and bypass dc-dc MICs — integrate a simple non-isolated intelligent dc-dc converter with each PV module to provide the advantages of dc-ac MICs at a lower cost. A suitable universal 150W 5A dc-dc converter design is presented based on two interleaved MOSFET half bridges. Testing shows Zero Voltage Switching (ZVS) keeps losses under 1W for bi-directional power flows up to 15W between two adjacent 12V PV modules for the bypass application, and efficiencies over 94% for most of the operational power range for the cascaded converter application. Based on the experimental results, potential optimizations to further reduce losses are discussed.