Modelling of a magnetocaloric system for cooling in the kilowatt range

A numerical time-dependent model of an active magnetic regenerator (AMR) was developed for cooling in the kilowatt range. Earlier numerical models have been mostly developed for cooling power in the 0.4 kW range. In contrast, this paper reports the applicability of magnetic refrigeration to the 50 kW range. A packed bed active magnetic regenerator was modelled and the influence of parameters such as geometry and operating parameters were studied for different geometries. The pressure drop for AMR bed length and particle diameter was also studied. High cooling power and coefficient of performance (COP) were achieved by optimization of the diameter of the magnetocaloric powder particles and operating frequency. The optimum operating conditions of the AMR for a cooling capacity of 50 kW was determined for a temperature span of 15 K. The predicted coefficient of performance (COP) was found to be ∼6, making it an attractive alternative to vapour compression systems.

Efficiency optimization for bidirectional IPT system

Compared with unidirectional inductive power transfer (UIPT) systems which are suitable for passive loads, bidirectional IPT (BIPT) systems can be used for active loads with power regenerative capability. There are numerous BIPT systems that have been proposed previously to achieve improved performance. However, typical BIPT systems are controlled through modulation of phase-shift of each converter while keeping the relative phase angle between voltages produced by two converters at ± 90 degrees. This paper presents theoretical analysis to show that there is a unique phase shift for each converter at which the inductive coils losses of the system is minimized for a given load. Simulated results of a BIPT system, compensated by CLCL resonant networks, are presented to demonstrate the applicability of the proposed concept and the validity of the mathematical model.

Cascaded multilevel converter based bidirectional inductive power transfer (BIPT) system

A typical low power IPT system employs an H-Bridge converter with a simple control strategy to generate a high frequency current from DC power supply. This paper proposes a cascaded multilevel converter for bidirectional IPT (BIPT) systems, which is suitable for low to medium power applications as well as for situations such as PV cells where several individual DC sources are to be utilized. A novel modulation strategy is proposed for the multilevel converter with the aim of minimizing switching losses. Series - Series (SS) compensation circuit is adopted for the IPT system and a mathematical model is presented to minimize the coil losses of the system under varying output power. Theoretical results presented in comparison to the simulations to demonstrate the applicability of the proposed concept and the validity of the developed model. The experimental results show the feasibility of the proposed phase shift modulation.

My System of Career Influences MSCI (Adult) Facilitator's Guide

Career development in the 21st century presents many challenges and opportunities to adults. They must now navigate a complex and rapidly changing world of work influenced by technology, globalisation and fluctuating economic conditions. The My System of Career Influences (MSCI) (Adult) is a qualitative career assessment tool based on the constructivist theory from cognitive psychology. Acknowledged as the third wave in cognitive science after psychoanalysis and behaviourism, constructivism emphasises the individual in the assessment and counselling process. Individuals actively participate in the construction of their own reality and are encouraged to respond to and deal with both anticipated and unanticipated events that influence their careers. The tool comprises a facilitator guide and participant workbooks. The guide describes the Systems Theory Framework of career development that provides the theoretical background to the MSCI as well as a step-by-step user guide to conducting the MSCI (Adult) process with individuals and groups. Each participant uses the accompanying MSCI (Adult) Workbook (sold separately) which they can complete and keep for later reference. With its attention to an holistic and storied approach to career intervention My System of Career Influences (MSCI) (Adult) is an essential resource for all career practitioners working with adults in today's workplaces.

My System of Career Influences MSCI (Adult) Workbook

NOTE: This client booklet is to be used in conjunction with the MSCI (Adult) Facilitators Guide. Career development in the 21st century presents many challenges and opportunities. Throughout your life you will make countless decisions and experience numerous transitions. Each decision may be subject to a range of influences, for example people we know may give us an opinion, we may be attracted to a particular place or a particular salary, or we may simply want a change. No two people will have the same pattern of influences. The My System of Career Influences MSCI (Adult) is a qualitative career assessment reflection process based on recent developments in theory and practice. It uses a constructivist view and encourages a narrative and story-based approach to your career development. It has been used successfully with employees by career development practitioners working in a range of businesses and organisations from large to small and in one-on-one career counselling sessions as well as in a group setting.

A Tradable Permit System in an Intertemporal Economy

It is known that in an intertemporal competitive economy, a tradable permit system may not achieve efficiency without setting appropriate permit interest rates (i.e., rewards for holding permits). To find the rates, however, we need to know in advance the path of efficient permit prices, which is difficult to obtain. This study intends to solve this problem in two ways. First, we analyze a special case in which the permit interest rates are given by a simple rule. For example, if the marginal abatement cost of pollution emission is constant, then the appropriate rate is to equal the monetary interest rate. As is the case for global warming, if the damage is caused in the future far beyond the planning period of the environmental program, the appropriate rate coincides with the marginal self-recovery of environmental stock under certain conditions. As a second approach, we propose a tradable permit system with a permit bank, as a mechanism by which the permit interest rates are generated endogenously without governmental intervention other than the issuance of permits. However, we also show that this approach raises the problem of indeterminacy of the equilibrium. © 2013 Springer Science+Business Media Dordrecht.

Use of the biolistic particle delivery system to transform fungal genomes

Biolistic delivery of transforming DNA into fungal genomes, especially when performed on uninucleate haploid conidia, has proven successful in bypassing the time-consuming repetitive purification of protoplasts used for the widely applied polyethylene glycol-mediated method. Biolistic transformation is also relatively quick compared to other available methods and provides a high percentage of stable transformants.

Environmental information provision, market valuation, and firm incentives: An empirical study of the Japanese PRTR system

The environmental performance of a listed firm could affect its level of investment in pollution prevention and its access to financial markets. Previous studies using Tobin's q that explore market response to environmental performance do not distinguish between the impact of performance on investment and market response, which may mislead conclusions. To overcome this problem, we simultaneously estimate the functions of the intangible asset, the replacement cost, and the toxic chemical risk. We find that the Japanese financial market does not value risk associated with toxic chemical releases. Nevertheless, even without market valuation, firms increase investment to reduce pollution. © 2010 by the Board of Regents of the University of Wisconsin System.

The pollution release and transfer register system in the U.S. and Japan : an analysis of productivity

This study analyzes Total Factor Productivity (TFP), which includes all categories of productivity. Our measure investigates productivity in the context of the provision and dissemination of environmental information policies. We investigated data on the emission of toxic chemical substances for the U.S. and Japanese manufacturing firms, including 386 firms for the period 1999-2007 and 466 firms for the period 2001-2008. The results show that productivity improved in all nine industrial sectors and that pollution levels were high in the U.S. and Japan from 2001 to 2007. In particular, the electronics industry improved rapidly after 2002 in both countries, which may be attributed to the enforcement of RoHS and the REACH directive in Europe. As a result of these stringent policies on toxic chemical emissions, the U.S. and Japanese firms, many of which export to the European market, have strong incentives to reduce their toxic chemical emissions.

Enhancing interdisciplinary learning with a learning management system

Interdisciplinary learning is a form of knowledge production that is increasingly being embraced as an educational approach in higher education. A role of information and communication technologies (ICT) is to enhance interdisciplinary learning. Issues surrounding the mix of interdisciplinary pedagogic methodologies and emerging digital technologies are worthy of investigation. In this paper, the authors report the findings of a study that examined student perceptions of an interdisciplinary course on information technology (IT) and visual design that utilized a learning management system. Using questionnaire instrumentation, the authors sought the perceptions of first-year university students enrolled in a newly formed interdisciplinary IT course. Results indicate that ICT-based interdisciplinary learners prefer a self-directed and collaborative instructional modality, as well as teacher presence and interventions in the online environment. The types of student participation can significantly influence how students perceive ICT-based interdisciplinary learning design.

Dual inverter based battery energy storage system for grid connected photovoltaic systems

This paper explores a new breed of energy storage system interfacing for grid connected photovoltaic (PV) systems. The proposed system uses the popular dual inverter topology in which one inverter is supplied by a PV cell array and the other by a Battery Energy Storage System (BESS). The resulting conversion structure is controlled in a way that both demand matching and maximum power point tracking of the PV cell array are performed simultaneously. This dual inverter topology can produces 2, 3, 4 and 5 level inverter voltage waveforms at the dc-link voltage ratios of 0:1, 1:1, 2:1 and 3:2 respectively. Since the output voltage of the PV cell array and the battery are uncorrelated and dynamically change, the resulting dc-link voltage ratio can take non-integer values as well. These noninteger dc-link voltage ratios produce unevenly distributed space vectors. Therefore, the main issue with the proposed system is the generation of undistorted current even in the presence of unevenly distributed and dynamically changing space vectors. A modified space vector modulation method is proposed in this paper to address this issue and its efficacy is proved by simulation results. The ability of the proposed system to act as an active power source is also verified.

Representing clients from courtroom to mediation settings : switching hats between adversarial advocacy and dispute resolution advocacy

In the vast majority of cases legal representation in mediation can provide many advantages for clients. However, in some, progress can be thwarted when lawyers do not understand the goals of the mediation process and their dispute resolution advocacy role. This article will explore some of the similarities and differences between the knowledge and skills that lawyers can draw upon when representing clients in adversarial court hearings as compared with non-adversarial settings, such as in mediations. One key distinction is the different approaches that legal representatives can use to effectively act in the best interests of clients. This article will highlight how an appreciation of such distinctions can assist lawyers to “switch” hats between their adversarial and non-adversarial roles. In particular, an understanding that the duty to promote the best interests of clients in mediation is consistent with a collaborative and problem-solving approach can greatly assist in the resolution process.

Development of a Solar Assisted Heat Pump Desalination System

In view of the growing global demand for energy and concern expressed for environmental degradation, a clean and "free" energy source, such as solar energy, has been receiving greater attention in recent years for various applications using different techniques. The Direct Expansion Solar Assisted Heat Pump (DX-SAHP) principle is one of the most promising techniques as it makes use of both solar and ambient energy. As the system has capability to function at low temperatures, it has the potential to operate at night in the tropics. The system utilizes multi-effect distillation (MED) principle for the conversion of seawater to fresh water. An experimental setup of the DX-SAHP desalination system has been built at the Department of Mechanical Engineering, National University of Singapore (NUS). This system uses two types of flat-plate solar collectors. One is called evaporator-collector, where no glazing is used, and the efficiency varies between 80 and 90%. The other type of collector is single-glazed, where the maximum efficiency is about 60%, and it is used for feed water heating. For the heat pump cycle, refrigerant R134a is used. The present study provides a comprehensive analyses and performance evaluation of this system under different operating and meteorological conditions of Singapore. The Coefficient of Performance (COP) of the heat pump system reached a maximum value of 10. For a single effect of desalination, the system shows a Performance Ratio (PR) of around 1.3.

Decision support system for age-related macular degeneration using discrete wavelet transform

Age-related macular degeneration (AMD) affects the central vision and subsequently may lead to visual loss in people over 60 years of age. There is no permanent cure for AMD, but early detection and successive treatment may improve the visual acuity. AMD is mainly classified into dry and wet type; however, dry AMD is more common in aging population. AMD is characterized by drusen, yellow pigmentation, and neovascularization. These lesions are examined through visual inspection of retinal fundus images by ophthalmologists. It is laborious, time-consuming, and resource-intensive. Hence, in this study, we have proposed an automated AMD detection system using discrete wavelet transform (DWT) and feature ranking strategies. The first four-order statistical moments (mean, variance, skewness, and kurtosis), energy, entropy, and Gini index-based features are extracted from DWT coefficients. We have used five (t test, Kullback–Lieber Divergence (KLD), Chernoff Bound and Bhattacharyya Distance, receiver operating characteristics curve-based, and Wilcoxon) feature ranking strategies to identify optimal feature set. A set of supervised classifiers namely support vector machine (SVM), decision tree, k -nearest neighbor ( k -NN), Naive Bayes, and probabilistic neural network were used to evaluate the highest performance measure using minimum number of features in classifying normal and dry AMD classes. The proposed framework obtained an average accuracy of 93.70 %, sensitivity of 91.11 %, and specificity of 96.30 % using KLD ranking and SVM classifier. We have also formulated an AMD Risk Index using selected features to classify the normal and dry AMD classes using one number. The proposed system can be used to assist the clinicians and also for mass AMD screening programs.

Efficiently capturing large, complex cultural heritage sites with a handheld mobile 3D laser mapping system

Accurate three-dimensional representations of cultural heritage sites are highly valuable for scientific study, conservation, and educational purposes. In addition to their use for archival purposes, 3D models enable efficient and precise measurement of relevant natural and architectural features. Many cultural heritage sites are large and complex, consisting of multiple structures spatially distributed over tens of thousands of square metres. The process of effectively digitising such geometrically complex locations requires measurements to be acquired from a variety of viewpoints. While several technologies exist for capturing the 3D structure of objects and environments, none are ideally suited to complex, large-scale sites, mainly due to their limited coverage or acquisition efficiency. We explore the use of a recently developed handheld mobile mapping system called Zebedee in cultural heritage applications. The Zebedee system is capable of efficiently mapping an environment in three dimensions by continually acquiring data as an operator holding the device traverses through the site. The system was deployed at the former Peel Island Lazaret, a culturally significant site in Queensland, Australia, consisting of dozens of buildings of various sizes spread across an area of approximately 400 × 250 m. With the Zebedee system, the site was scanned in half a day, and a detailed 3D point cloud model (with over 520 million points) was generated from the 3.6 hours of acquired data in 2.6 hours. We present results demonstrating that Zebedee was able to accurately capture both site context and building detail comparable in accuracy to manual measurement techniques, and at a greatly increased level of efficiency and scope. The scan allowed us to record derelict buildings that previously could not be measured because of the scale and complexity of the site. The resulting 3D model captures both interior and exterior features of buildings, including structure, materials, and the contents of rooms.