k-ε Predictions of the initial mixing of desalination discharges

Predictions from a k-ε model are compared with recently acquired experimental data from inclined negatively buoyant discharges. The k-ε model is part of a standard computational fluid dynamics package (CFX). Two approaches are taken when implementing the model. One involves using an essentially standard form of the model to predict flow behaviour. The other approach involves calibrating the model, through adjustment of the turbulent Schmidt number in the tracer transport equation, to achieve reasonable predictions for positively buoyant vertical discharges and then applying it to inclined negatively buoyant discharges. While the calibrated approach improves the predictions of some bulk parameters (notably the tracer spread and dilution) when compared to predictions from the standard model, the overall effect on the quality of the predictions is small. Comparisons with experimental data indicate that predictions from both the standard and calibrated simulations compare favourably with trajectory data, but integrated dilution predictions at the centreline maximum height are conservative (mean-integrated concentrations are over-predicted). The standard and calibrated k-ε predictions confirm the importance of buoyant instabilities on the lower (inner) side of the flow, the effects of which are clearly evident in the mean concentration profiles. However, these simulations have a tendency to overestimate the influence of stabilizing density gradients on the upper (outer) side of the flow and are unable to effectively predict the cross-sectional distribution of a tracer. In contrast to a previous study, the above comparisons indicate that predictions of bulk parameters from such models can be poor and indeed are no better than those obtained from relatively simple analytical solutions.     

Capital assets and intercultural borderlands: socio-cultural challenges for natural resource management

In their design or implementation, many natural resource management (NRM) programs ignore critical socio-cultural dimensions of the challenge to advance sustainability. Building on particular ideas about culture and human ecosystems, we combine the strengths of the capital assets model of sustainability and the idea of intercultural borderlands to respond to this gap. To advance our thesis about the utility of these tools, we critically reviewed and analysed a cross-disciplinary literature relating to the socio-cultural dimensions of NRM. This paper stems from that labour and examines particular tensions that arise in land management as a result of Australians' specific colonial and postcolonial legacies. These tensions--related to ethnicity, gender, population, age and health--are among the threads in the larger tapestry that comprises the socio-cultural dimensions of NRM. For the Australian case, they are central, longstanding and persistent, and thus worthy of analysis; and they are applicable in general terms to other places with similar histories of settlement and land use.     

Issues and options for the safe destruction and disposal of used injection materials

It has long been known that the re-use of syringes can cause the spread of infections such as HIV and hepatitis. The production of disposable syringes was undertaken as a solution to the infection problem. In developing countries, however, there has been an unwanted result: the re-use and recycling of disposable syringes. One response has been "auto-disable" syringes that lock the plug and piston in place after a single use. These types of approaches, however, have resulted in greatly increased volumes of used injection materials. This is a particular problem in developing countries where contaminated medical wastes find their way into municipal garbage where people are known to scavenge and recycle. This poses obvious health risks, both in terms of direct exposure and environmental contamination. This study of issues and options for the safe destruction and disposal of used injection materials was undertaken using document analysis was to bring together and summarise approaches to the inter-related issues of "syringe re-use" and "clinical waste disposal". The authors suggest that holistic approaches to syringe use and clinical waste disposal need to be utilized in addressing the situation outlined. The focus is on technology and procedures that may be adaptable to rural areas in developing countries.     

Column leaching and sorption experiments to assess the mobility of potentially toxic elements in industrially contaminated land

Made-up ground collected from layers of a trial pit excavated on a former industrial site was treated with artificial rainwater in a series of column leaching and sorption experiments. Metal mobility and the ability of various layers of material obtained from the pit to act as sources or sinks of potentially toxic elements were assessed. Samples from different layers varied in their abilities to raise the pH of rainwater applied at pH 3.5 and 4.3, and this was reflected in the amounts of metals mobilised by the rainwater as it percolated through the soil column. Material from the top two layers of the pit released cadmium, copper, manganese, lead, nickel and zinc to the aqueous phase, but the lower layers, with higher buffering capacity, were able to resist acidification even when the equivalent of 12 months' rainfall (western UK) was applied. Column sorption experiments confirmed the ability of material from layer 4 (48-50 cm) to take up copper, manganese and zinc. Metals were determined in the leachates by flame and electrothermal atomic absorption spectrometry and principle anions by ion chromatography.     

Evaluating the process of triple bottom line reporting: Increasing the potential for change1

Abstract

This paper presents an evaluation framework that aims to improve the outcomes of triple bottom line (TBL) reporting. Currently, most assessments of TBL reporting focus on report content. Our view is that effective evaluation of TBL reporting should go beyond reports as the outputs of a process and focus on what is being learned through the process, the capacity- and relationship-building that might eventuate, and how this impacts on the development of sustainability. To enable more effective reflection of TBL reporting processes, we developed a set of evaluation criteria focused on the process of reporting. These criteria were identified from case studies of social, environmental and/or sustainability reporting processes documented in the literature. A large number of potential criteria were synthesised into three desired outcomes of TBL reporting and 10 prompts for discussion and reflection during evaluation. This evaluation framework should assist those dedicated to challenging assumptions that inhibit progress towards a sustainable future for society.