Biodiversity and environmental education: A contradiction?

The need for the maintenance of biodiversity has become a much-debated environmental concern. However, calling for continued biodiversity exposes one to potential accusations of caring more for the natural environment than for people. This article briefly reviews the development of environmental education and provides an overview of the concepts “biodiversity”, “sustainable development” and “sustainable consumption”. Reasons for maintaining biodiversity while simultaneously allowing for sustainable development and sustainable consumption are considered, but the main purpose of the article is to raise questions about current environmental education practice in South Africa and whether the concern of biodiversity is in actual fact addressed

A new behavioural model for performance evaluation of common mode chokes

A galvanically isolated three-phase AC/AC converter with a high-frequency AC-link has been analyzed from an EMC point of view. This is a special configuration because of a large number of switches, a high frequency transformer, and a fourwire output. The essential coupling paths are identified. Corresponding suppression remedies are given. The results, before and after measures, have been presented to demonstrate the improvement in EMC. Keywords: AC/AC converter; electromagnetic interference; galvanically isolate

Trickle-bed CFD studies in the catalytic wet oxidation of phenolic acids

An Euler-Euler computational fluid model was developed successfully for the hydrodynamic prediction of a trickle-bed reactor (TBR) designed for advanced wastewater treatment facilities. Catalytic wet air oxidation of phenolic acids was simulated in a TBR by means of computational fluid dynamic (CFD) in the temperature range and pressures . The hydrodynamic model validation was accomplished through the comparison of simulated pressure drop and liquid holdup with experimental data from the literature. In a broad range of gas and liquid flows studied (G=0.10-0.70 and ) at different operation conditions, CFD demonstrated the considerable effect of operating pressure in pressure drop, whereas a minor influence was detected for the liquid holdup. CFD runs were then performed for the catalytic wet air oxidation of aqueous phenolic acids solution. The reactor behaviour was analysed by means of total organic carbon profiles which reflected the influence of temperature, pressure, gas-liquid flows and initial pollutant concentration.http://www.sciencedirect.com/science/article/B6TFK-4PPMXS0-1/1/2dabed7df5e98dfd85f3fef6ef64782

Turbulence modelling of multiphase flow in high-pressure trickle-bed reactors

http://www.sciencedirect.com/science/article/B6TFK-4VB01VS-7/2/7dcce0ca6c1ed57a847371407b038f1

Simulation-Based Decision Support System to Improve Material Flow of a Textile Company

To remain competitive, companies must continuously improve the processes at hand, be they administrative, production, or logistics. The objective of the study described in this paper was to develop a decision-making tool based on a simulation model to support the production of knits and damask fabrics. The tool was used to test different control strategies for material flow, from the raw material warehouse to the finished product warehouse, and thus can also be used to evaluate the impacts of these strategies on the productivity. The data upon which the decision support tool was built were collected from five sectors of the plant: the raw material warehouse, knit production, damask production, finishing work, and the finished product warehouse. The decision support tool met the objectives of the project, with all five strategies developed showing positive results. Knit and damask production rates increased by up to 8% and 44%, respectively, and a reduction of 75% was observed in the waiting time on the point of entry to the finishing work area, compared to the company’s existing system.info:eu-repo/semantics/publishedVersio

Final results from the EU project AVATAR: aerodynamic modelling of 10 MW wind turbines

This paper presents final results from the EU project AVATAR in which aerodynamic models are improved and validated for wind turbines on a scale of 10 MW and more. Special attention is paid to the improvement of low fidelity engineering (BEM based) models with higher fidelity (CFD) models but also with intermediate fidelity free vortex wake (FVW) models. The latter methods were found to be a good basis for improvement of induction modelling in engineering methods amongst others for the prediction of yawed cases, which in AVATAR was found to be one of the most challenging subjects to model. FVW methods also helped to improve the prediction of tip losses. Aero-elastic calculations with BEM based and FVW based models showed that fatigue loads for normal production cases were over predicted with approximately 15% or even more. It should then be realised that the outcome of BEM based models does not only depend on the choice of engineering add-ons (as is often assumed) but it is also heavily dependent on the way the induced velocities are solved. To this end an annulus and element approach are discussed which are assessed with the aid of FVW methods. For the prediction of fatigue loads the so-called element approach is recommended but the derived yaw models rely on an annulus approach which pleads for a generalised solution method for the induced velocities

POLCA control in two-stage production systems

POLCA (Paired-cell Overlapping Loops of Cards with Authorization) is a decision support system for material flow control under Quick Response Manufacturing. It operates in the context of low-volume, high-mix, and cellular manufacturing. While there is an increasing literature on POLCA performance, current studies usually assume full availability of components (or parts) at assembly stations, neglecting parts manufacturing and feeding. Therefore, this study uses simulation to assess POLCA performance in a two-stage production system, where at the first stage parts are manufactured and at the second, they are assembled into end-products. The study demonstrates that using POLCA to control both production stages, manufacturing and assembly, significantly outperforms the use of POLCA at the assembly stage only, leading to important reductions of the total throughput time of orders and on the percentage of tardy orders. Statistical analysis of our results was conducted using ANOVA.info:eu-repo/semantics/publishedVersio

Latest results from the EU project AVATAR: aerodynamic modelling of 10 MW wind turbines

This paper presents the most recent results from the EU project AVATAR in which aerodynamic models are improved and validated for wind turbines on a scale of 10 MW and more. Measurements on a DU 00-W-212 airfoil are presented which have been taken in the pressurized DNW-HDG wind tunnel up to a Reynolds number of 15 Million. These measurements are compared with measurements in the LM wind tunnel for Reynolds numbers of 3 and 6 Million and with calculational results. In the analysis of results special attention is paid to high Reynolds numbers effects. CFD calculations on airfoil performance showed an unexpected large scatter which eventually was reduced by paying even more attention to grid independency and domain size in relation to grid topology. Moreover calculations are presented on flow devices (leading and trailing edge flaps and vortex generators). Finally results are shown between results from 3D rotor models where a comparison is made between results from vortex wake methods and BEM methods at yawed conditions

A pesca e o conhecimento ecológico local dos pescadores de acará-disco (Symphysodon aequifasciatus, Pellegrin 1904: Cichlidae) na Reserva de Desenvolvimento Sustentável Piagaçu-Purus, baixo rio Purus, Brasil

The discus fish (Symphysodon aequifasciatus, Pellegrin 1904), an endemic cichlid from the Amazon basin, is one of the most popular ornamental fish species in the world. However, there is little information available in the scientific literature on the exploitation of this species in its natural habitat. In this article we describe the small-scale discus fisheries activity in the Reserva de Desenvolvimento Sustentável Piagaçu-Purus (RDS-PP), lower Purus River, Brazil, based on field observations, structured and open-ended interviews with fishermen and local inhabitants. Discus fishery is seasonal, occurring mainly in the dry season. Local fishermen use fish attractors to catch the species and underwater hearing methods to estimate its presence and abundance. Discus fishes are locally kept in wooden storage tanks and carried in plastic containers for distribution in regional markets by means of fishing boats, commercial boat lines or rafts. Discuses are sold in Manaus, State of Amazonas, to export companies specialized in ornamental fish trade. We describe the local ecological knowledge on the discus among fishermen living within the RDS-PP and discuss its importance for ornamental fishery management in that protected area