93 research outputs found

    An institutional perspective on water sector performance in Thailand

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    University of Technology Sydney. Faculty of Engineering and Information Technology.In recognition of the criticality of water in ensuring socio-economic prosperity of a vastly agrarian country (Thailand), the Thai policy makers have made massive investments over the years to establish and manage country’s water systems. Notwithstanding this, the Thai water systems have continued to perform poorly. For example, the performance (assessed by employing a Multi-stage Malmquist-based DEA method developed in this research) of the Thai water sector, comprising 25 key water basins, deteriorated considerably over the period 1987-2017, for all of its functional stages, namely, water supply, water usage, and water-benefits (i.e., earning of water-dependent farmers). Further, efforts by successive Thai governments to improve water sector performance, primarily by restructuring the proximate water-specific institutions, have largely failed. Despite this failure, the faith of the Thai policy makers in the appropriateness of this approach (i.e., restructuring of proximate water institutions) to improving water sector performance appears to have remained unshaken. This faith – this research contends – is unfounded and hence unlikely to improve water sector performance. The water sector performance can only be improved – this research further holds – by improving the efficacy of country’s socio-political institutions (reflecting country’s socio-political imperatives, its cultural traditions and belief systems) that provide the raison d'être for the water-sector institutions, in fact for the water sector itself. The veracity of this argument is ascertained in this research through the application of two conjoint sets of empirical analyses, namely, correlation and causality (supported by Spearman’s rank correlations coefficients) and multi-stage and cross-sectional econometrics. These analyses clearly establish the centrality of socio-political institutions in determining water sector performance. Inspired by this finding, this research delineates the contours of a sound and pragmatic institutional framework (reform model) that could considerably and enduringly improve the performance of the Thai water sector. Further, although this research has focused on the water sector of Thailand, its relevance extends to other countries and to other types of infrastructure. Increasing emphases around the world on institutions and governance as means to improve socio-economic outcomes is a testimony to the soundness of the discourse developed in this research

    Structural Design of Partitioned Stator Doubly Salient Permanent Magnet Generator for Power Output Improvement

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    Partitioned stator doubly salient permanent magnet generators (PS-DSPGs) have been extensively used for electrical generation mainly due to their high reliability, high electromotive force (EMF), and high-power output. Therefore, we aim to improve the output power of a PS-DSPG by designing the optimal configuration of generator pole structure. Electrical characteristics including the magnetic flux linkage distribution, phase EMF, cogging torque, voltage regulation, and power output profile were characterized by using the finite element method. After optimizing the generator pole structure including the angle of air gap arc width, it was found that the proposed PS-DSPG with 18/15 (stator/rotor) pole structure with optimized air gap arc width could produce higher EMF of about 23.24% than a conventional structure because this structure has the suitable number of pole structures. Also, an analysis of voltage regulation and power output profiles under the loaded condition were carried out, and it was indicated that the PS-DSPG based on the suitable 18/15-pole structure could provide the best machine performance where the output power is 11.63% higher than the conventional structure. Hence, the proposed PS-DSPG with 18/15-pole structure can appropriately be utilized for electrical generation, especially in low-speed operated generator applications

    Free Layer Thickness Dependence of the Stability in Co2(Mn0.6Fe0.4)Ge Heusler Based CPP-GMR Read Sensor for Areal Density of 1 Tb/in2

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    Current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) read sensors based on Heusler alloys are promising candidates for ultrahigh areal densities of magnetic data storage technology. In particular, the thickness of reader structures is one of the key factors for the development of practical CPP-GMR sensors. In this research, we studied the dependence of the free layer thickness on the stability of the Co2(Mn0.6Fe0.4)Ge Heusler-based CPP-GMR read head for an areal density of 1 Tb/in2, aiming to determine the appropriate layer thickness. The evaluations were done through simulations based on micromagnetic modelling. The reader stability indicators, including the magnetoresistance (MR) ratio, readback signal, dibit response asymmetry parameter, and power spectral density profile, were characterized and discussed. Our analysis demonstrates that the reader with a free layer thickness of 3 nm indicates the best stability performance for this particular head. A reasonably large MR ratio of 26% was obtained by the reader having this suitable layer thickness. The findings can be utilized to improve the design of the CPP-GMR reader for use in ultrahigh magnetic recording densities

    Optimal Design of Electric Vehicle Fast-Charging Station’s Structure Using Metaheuristic Algorithms

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    The fast development of electric vehicles (EVs) has resulted in several topics of research in this area, such as the development of a charging pricing strategy, charging control, location of the charging station, and the structure within the charging station. This paper proposes the optimal design of the structure of an EV fast-charging station (EVFCS) connected with a renewable energy source and battery energy storage systems (BESS) by using metaheuristic algorithms. The optimal design of this structure aims to find the number and power of chargers. Moreover, the renewable energy source and BESS can reduce the impact on the grid, so these energy sources are considered as ones of the optimally-designed structure of EVFCS in this work. Thus, it is necessary to determine the optimal sizing of the renewable energy source, BESS, and the grid power connected to EVFCS. This optimal structure can improve the profitability of the station. To solve the optimization problem, three metaheuristic algorithms, including particle swarm optimization (PSO), Salp swarm algorithm (SSA), and arithmetic optimization algorithm (AOA), are adopted. These algorithms aim to find the optimal structure which maximizes the profit of the EVFCS determined by its net present value (NPV), and the results obtained from these algorithms were compared. The results demonstrate that all considered algorithms could find the feasible solutions of the optimal design of the EVFCS structure where PSO provided the best NPV, followed by AOA and SSA

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