The Politics of Local Environmental Management

Environmental management on the part of local government is now being accorded a high priority in certain parts of Australia. To date, for example, approximately 25 local councils in Victoria – either singly or jointly – have been involved in the development of Local Conservation Strategies (LCSs), most with some financial assistance from the Government of Victoria's Office of the Environment. The majority of these LCSs relate to urban rather than rural settings. There have been differences of approach depending upon such parameters as the initial professional training of the main officers concerned, the council's level of political commitment to the idea, and the socio-economic make-up of the local community.     

Defect-oriented testing and defective-part-level prediction

After an integrated circuit (IC) design is complete, but before first silicon arrives from the manufacturing facility, the design team prepares a set of test patterns to isolate defective parts. Applying this test pattern set to every manufactured part reduces the fraction of defective parts erroneously sold to customers as defect-free parts. This fraction is referred to as the defect level (DL). However, many IC manufacturers quote defective part level, which is obtained by multiplying the defect level by one million to give the number of defective parts per million. Ideally, we could accurately estimate the defective part level by analyzing the circuit structure, the applied test-pattern set, and the manufacturing yield. If the expected defective part level exceeded some specified value, then either the test pattern set or (in extreme cases) the design could be modified to achieve adequate quality. Although the IC industry widely accepts stuck-at fault detection as a key test-quality figure of merit, it is nevertheless necessary to detect other defect types seen in real manufacturing environments. A defective-part-level model combined with a method for choosing test patterns that use site observation can predict defect levels in submicron ICs more accurately than simple stuck-at fault analysis     

Modelling to determine the optimal porosity of shelterbelts for the capture of agricultural spray drift

Shelterbelts are not only useful as windbreak protection for stock and crops but can also be used to capture spray drift and reduce the spread to non-crop areas with important environmental consequences. The porosity of a shelterbelt can significantly influence the ability to capture spray drift. The aim of this work is to determine the optimal shelterbelt porosity that maximises spray drift capture. This has implications to future shelterbelt plantings and species selection. Here a model is developed for the flow through and over a shelterbelt. This model is used in conjunction with a spray capture model to determine the capture efficiency of shelterbelts with different porosities. Values of the optical porosity between 10% and 40% are found to give the best capture efficiency over a range of shelterbelt structures with the optimum generally around 25%. It is hoped that in the future experimental validation of these models will be undertaken. This will further enhance the understanding and use of shelterbelts as spray mitigation devices.     

An investigation of fracture and fatigue in a metal/polymer composite

This article presents the results of a combined experimental and analytical study of the fatigue and fracture behavior of a polymer/metal composite which was developed recently for self-lubricating applications in automotive engines that utilize liquefied natural gas as fuel. For comparison, the microstructure and the fatigue and fracture behavior of a nonpolymer-containing “matrix” material are also presented. Since the crack profiles observed in both systems under monotonic or cyclic loading reveal significant components of ligament bridging, micromechanics models are presented for the modeling of crack bridging. The resulting predictions of resistance-curve behavior are compared with measured resistance curves. The shielding effects of ligament bridging are also quantified under cyclic loading. The implications of the work are also discussed for the modeling of fatigue damage and fracture in polymer/metal coatings.     

Cooperative Vaccinia Infection Demonstrated at the Single-Cell Level Using FluidFM

The mechanisms used by viruses to enter and replicate within host cells are subjects of intense investigation. These studies are ultimately aimed at development of new drugs that interfere with these processes. Virus entry and infection are generally monitored by dispensing bulk virus suspensions on layers of cells without accounting for the fate of each virion. Here, we take advantage of the recently developed FluidFM to deposit single vaccinia virions onto individual cells in a controlled manner. While the majority of virions were blocked prior to early gene expression, infection of individual cells increased in a nondeterministic fashion with respect to the number of viruses placed. Microscopic analyses of several stages of the virus lifecycle indicated that this was the result of cooperativity between virions during early stages of infection. These findings highlight the importance of performing controlled virus infection experiments at the single cell level.     

Impairment of Coronary Arteriolar Endothelium-Dependent Dilation after Multi-Walled Carbon Nanotube Inhalation: A Time-Course Study

Engineered nanomaterials have been developed for widespread applications due to many highly unique and desirable characteristics. The purpose of this study was to assess pulmonary inflammation and subepicardial arteriolar reactivity in response to multi-walled carbon nanotube (MWCNT) inhalation and evaluate the time course of vascular alterations. Rats were exposed to MWCNT aerosols producing pulmonary deposition. Pulmonary inflammation via bronchoalveolar lavage and MWCNT translocation from the lungs to systemic organs was evident 24 h post-inhalation. Coronary arterioles were evaluated 24–168 h post-exposure to determine microvascular response to changes in transmural pressure, endothelium-dependent and -independent reactivity. Myogenic responsiveness, vascular smooth muscle reactivity to nitric oxide, and α-adrenergic responses all remained intact. However, a severe impact on endothelium-dependent dilation was observed within 24 h after MWCNT inhalation, a condition which improved, but did not fully return to control after 168 h. In conclusion, results indicate that MWCNT inhalation not only leads to pulmonary inflammation and cytotoxicity at low lung burdens, but also a low level of particle translocation to systemic organs. MWCNT inhalation also leads to impairments of endothelium-dependent dilation in the coronary microcirculation within 24 h, a condition which does not fully dissipate within 168 h. The innovations within the field of nanotechnology, while exciting and novel, can only reach their full potential if toxicity is first properly assessed.     

A statistical approach for the integrated analysis of mine-induced seismicity and numerical stress estimates, a case study—Part I: developing the relations

Integrated analyses at a number of underground operations have suggested that qualitative relations may exist between microseismic variable values estimated in real-time from mine seismic systems and the stress estimates provided by numerical models. In this study, multivariate statistical techniques were used to evaluate whether quantitative relations could be formed using data from the Creighton Mine in Sudbury, Ontario. It is believed that if sufficiently reliable relations could be developed, they might then be exploited to better characterize the state of the rock mass and provide insight beyond what could be obtained from either data set in isolation. This insight could then be used to eventually impact both short- and long-term mine design decisions.This paper represents the second part of a two part series and describes the evaluation of the 11 statistically significant relations that were formed in the first paper between variables within the stress and seismic databases. Specifically, the model adequacy and the stability of each relation was evaluated. In addition, the prediction capabilities of each relation were evaluated and the relations were interpreted relative to prior experience and physical theory.The results of this component of the study indicated that all but three of the developed relations met the statistical requirements for relations of this type and all were shown to be quite stable. In terms of prediction, it was demonstrated that this could best be achieved through the application of Discriminant Function Analysis. This technique was shown to be capable of suggesting which events were generated under relatively high-stress conditions, though the technique was less successful at correctly identifying events generated under lower stress conditions. Interpretation focussed on the relation between the stress conditions at the source and two particular variables from the seismic database and concluded that the observed variations in source strength were primarily controlled by spatial variations in confinement. The importance of a rigorous methodology was also discussed, as was potential ways in which the relations of the types formed in this study could impact mine design decisions.     

Distribution of dopamine receptors and dopamine receptor homologs in the brain of the honey bee, Apis mellifera L

In the brain of the honey bee, Apis mellifera, the radioligands [3H]-SCH23390 and [3H]-spiperone recognise D1- and D2-like receptors, respectively. In addition to being pharmacologically distinct and exhibiting significantly different expression profiles during the lifetime of the bee, [3H]-SCH23390- and [3H]-spiperone-binding sites differ markedly in their distribution within the brain. Estimates of [3H]-SCH23390-binding site density are highest in the somatal rind, whereas [3H]-spiperone-binding sites are most concentrated in the beta lobe neuropil of the mushroom bodies. Molecular cloning techniques have been used to identify two honey bee genes encoding dopamine receptor homologs. The first is the honey bee counterpart of a Drosophila D1-like dopamine receptor and is expressed in the mushroom bodies of both workers and drones. The second is related to D2-like dopamine receptors from vertebrates and is expressed in the brain of the bee, but the precise distribution of expression is not yet known.     

An investigation of the micromechanisms of fatigue crack growth in structural gas turbine engine alloys

This paper presents an overview of fatigue fracture modes in selected structural alloys employed in gas turbine engines. These include the mechanisms of fatigue crack growth in the near-threshold, Paris and high-K regimes obtained from Ti-6Al-4V, Inconel 718 and PWA 1472 (a single crystal nickel-based superalloy of similar chemical composition to Inconel 718). Fatigue fracture modes in these materials are shown to be strong functions of the stress intensity factor range, K, and the maximum stress intensity factor, K _max. Fatigue mechanism maps are also presented to show the parametric ranges of K and K _max corresponding to the different fatigue fracture modes.     

Sterol biosynthesis inhibitors: Their current status and modes of action

The mechanism of each of the reactions in the post-squalene segment of the fungal and higher plant sterol biosynthetic pathway is outlined. The inhibitors of the enzymes catalyzing the reactions are described and how inhibition is brought about is explained in the areas where it is known. Based on a paper presented at the Symposium on Plant and Fungal Sterols: Biosynthesis, Metabolism and Function, held at the AOCS Annual Meeting, Baltimore, MD, April 1990.