This research investigates a low-cost generator and power electronics unit for smallscale (<10kW) wind turbines, for both standalone and grid-connected applications. The proposed system uses a high-inductance permanent magnet generator together with a switched-mode rectifier (SMR) to produce a variable magnitude output current. The high inductance characteristic allows the generator to operate as a current source, which has the following advantages over conventional low-inductance generator (voltage source) systems: it offers simple control, and avoids the need for bulky / costly energy storage elements, such as capacitors and inductors. The SMR duty-cycle is controlled in an open-loop manner such that 1) maximum power is obtained for wind speeds below rated, and 2) the output power and turbine speed is limited to safe values above rated wind speed. This topology also has the ability to extract power at low wind speeds, which is well suited to small-scale wind turbines, as there is often limited flexibility in their location and these commonly see low average wind speeds. The thesis is divided into two parts; the first part examines the use of the SMR as a DC-DC converter, for use in standalone applications. The duty-cycle is essentially kept constant, and is only varied for maximum power tracking and turbine speed / power limiting purposes. The SMR operates in to a fixed voltage source load, and has the ability to allow current and hence power to be drawn from the generator even at low wind and hence turbine speeds, making it ideal for battery charging applications. Initial dynamometer testing and limited wind-tunnel testing of a commercially available wind turbine show that turbine power can be maximised and its speed can be limited by adjusting the SMR duty-cycle in an open-loop manner. The second part of the thesis examines the use of the SMR as a DC-AC converter for grid-connected applications. The duty-cycle is now modulated sinusoidally at the mains frequency such that the SMR produces an output current that resembles a fullwave rectified sinewave that is synchronised to the mains voltage. An additional H-bridge inverter circuit and low-pass filter is used to unfold, filter and feed the sinusoidal output current in to the utility grid. Simulation and initial resistive load and preliminary grid-connected tests were used to prove the inverter concept, however, the permanent magnet generator current source is identified as non-ideal and causes unwanted harmonic distortion. The generator harmonics are analysed, and the system performance is compared with the Australian Standard THD requirement. It is concluded that the harmonics are caused by 1) the low-cost single-phase output design, 2) the use of an uncontrolled rectifier, and 3) the finite back-EMF voltage. The extent of these harmonics can be predicted based on the inverter operating conditions. A feed-forward current compensation control algorithm is investigated, and shown to be effective at removing the harmonics caused by the nonideal current source. In addition, the unipolar PWM switching scheme, and its harmonic components are analysed. The low-pass filter design is discussed, with an emphasis on power factor and THD grid requirements. A normalised filter design approach is used that shows how design aspects, such as cutoff frequency and quality factor, affect the filter performance. The filter design is shown to be a trade-off between the output current THD, power loss, and quality factor. The final chapter summarises the thesis with the design and simulation of a 1kW single-phase grid-connected inverter. The inverter is designed based on the low-pass filter and feed-forward compensation analysis, and is shown to deliver an output current to the utility grid that adheres to the Australian Standards. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1375316 / Thesis (Ph.D.) - University of Adelaide, School of Electrical and Electronic Engineering, 2009

Literature on performance management (PM) indicates that the concept has gained momentum in its use by organisations, with the ultimate goal of improving business performance. It is argued that PM makes significant contributions to individual employees and organisational performance by enabling expectations to be defined and agreed in terms of the role, responsibilities and accountabilities, and providing opportunities for individuals to identify their own goals and to develop their skills and competencies. However, there has been much debate as to whether PM optimises or leads to improved overall business performance as other factors other than human resources policies, such as personality, job role experiences, and structural factors, may have a detrimental influence on job performance. Moreover, several studies have shown that PM, and performance management systems (PMS) has resulted in unintended impacts, both positive and negative, in addition to those sought by organisations. This research is an investigation into the perception of managers and care assistants in private care of the elderly in care homes in Scotland on the impact of performance management systems. Use is made of both PM literature and empirical research to understand the perceived impact of the PMS with the ultimate aim of developing an enhanced PMS framework. In addition to documents review, twenty-four in-depth interviews were conducted, comprising of eight managers and sixteen care assistants drawn from eight different private care homes. The interviews focused on eight key PM elements, the PM concept, goal-setting, performance reviews, performance measurement, supporting performance, rewards system, training and development, and managing underperformance. The interview results from managers and care assistants were compared with the normative/ideal PM practice from the PM literature to determine how PMS is being implemented in the private care homes. The research findings reveal an overall positive perception towards PMS implementation by managers. However, the care assistants raised many of concerns which influenced a negative perception towards the PMS implementation. This was used as the basis for developing recommendations for an enhanced PMS framework. Therecommendations are centred around the identified two main problem areas: management/leadership style and the communication process. In addition to staff involvement in performance planning, and a fair underperformance management process, three other theories: power distance, vertical and horizontal trust, and the principal-agent problem were recommended to private care homes. This would help change the negative perception towards PMS implementation by care assistants.

This paper provides a risk assessment of pertinent toxic contaminants in the tailings of the Iron King Mine using a model of aeolian transport fated in human alveolar lung. Here, we studied particulate matter of tailings that are 10 microns (𝜇𝑚) or less in diameter (𝑃𝑀₁₀) because these is most hazardous fraction. We used in-vitro bioaccessibility and in-vivo Microtox® data to determine the relationships between chronic inhalation of these tailings. Our data suggest that arsenic and zinc are the two principle drivers for toxicity of the Iron King Mine’s PM₁₀ tailings and that arsenic will solubilize in human alveolar biofluids at the expense of other noteworthy elemental contaminants in the tailings. The principle contaminant of concern for chronic exposure is arsenic, due to its increased bioaccessibility over time. Our data show that synthetic lung fluid (SLF) mitigates the toxic effects of arsenic, despite its increase in bioaccessibility over time. Therefore, we suggest a buffering mechanism of phosphate competition with arsenate to explain this mitigation of toxicity in SLF. We conclude that public health risk of chronic inhalation of IKM PM₁₀ tailings may be less severe than would otherwise be suggested by high concentrations of toxic contamination in the tailings impoundment.

TCC (graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Engenharia Civil. / Submitted by Robespierre Xavier da Silva Junior null (robespierre.xavier) on 2016-07-05T23:53:05Z No. of bitstreams: 1 TCC-Robespierre X. S. Jr.pdf: 3880652 bytes, checksum: bc7803e50aaaf83faa6d6bc1e22cb4ca (MD5) / Approved for entry into archive by LIA CAETANO BASTOS null (lia.c.bastos@ufsc.br) on 2016-07-18T20:38:34Z (GMT) No. of bitstreams: 1 TCC-Robespierre X. S. Jr.pdf: 3880652 bytes, checksum: bc7803e50aaaf83faa6d6bc1e22cb4ca (MD5) / Made available in DSpace on 2016-07-18T20:38:34Z (GMT). No. of bitstreams: 1 TCC-Robespierre X. S. Jr.pdf: 3880652 bytes, checksum: bc7803e50aaaf83faa6d6bc1e22cb4ca (MD5) / Este trabalho tem como princípio apresentar a análise de incerteza nas previsões meteorológicas e hidrológicas da ferramenta computacional SPEHC. Para tanto, inicia-se o presente estudo apresentando uma introdução que salienta quais modelos meteorológicos e hidrológico utilizados nos cálculos. Além dos modelos implementados, os estudos tiveram como foco realizar análises na sub-bacia do Rio do Peixe, que tem como exutório o município de Tangará. Os resultados encontrados foram dispostos em três partes distintas que são as seguintes: análise de incerteza meteorológica, calibração do modelo hidrológico e análise de incertezas hidrológicas. Os estudos de incerteza meteorológica tiveram como início determinar para a região do presente estudo a diferença nos valores acumulados de precipitação dos dados do TRMM (que são utilizados na calibração do modelo) e os valores observados nos sete pluviômetros espalhados na região da sub-bacia hidrográfica. Após este cálculo foi elaborada uma análise em um evento crítico de precipitação, sendo que os modelos meteorológico BRAMS e ETA não foram coerentemente representativos nas estimativas pluviométricas nesse período de estudo. A segunda parte dos resultados apresentou a calibração do modelo hidrológico PM Tank Model que é utilizado na ferramenta computacional SPEHC. Para tanto, optou-se por elaborar uma série de dez calibrações diferentes para a mesma região. Este fato foi proposto para servir de base nas análises de previsão hidrológica. Na última etapa deste estudo foram analisados os dados de previsão hidrológica e concluiu-se que todas as análises referentes a previsão de vazão são diretamente interligadas a qualidade dos dados de precipitação. Sendo assim, o estudo de previsão hidrológica se ateve a analisar qualitativamente os resultados encontrados e identificando padrões assumidos nos referidos gráficos. Por fim, o presente estudo concluiu que as previsões hidrológicas são dependentes das previsões meteorológicas e portanto todas as incertezas atreladas a estas são repassadas a modelagem de vazão. / This paper has the principle analyzing uncertainties in weather and hydrological forecasts on software SPEHC. Therefore, begins this study presenting an introduction about meteorological and hydrological models used in the calculations. In addition to the models implemented, studies have focused on performing analysis on the Fish River sub-basin, where the discharge measure is in the city of Tangará. The results were arranged in three distinct parts which are as follows: weather uncertainty analysis, calibration of the hydrological model and analysis of hydrological uncertainties. The weather uncertainty studies beginning to determine for this study region the difference in cumulative values of precipitation from TRMM (used in model calibration) and the values observed in the seven rain gauges in the sub-basin area. After this, was prepared an analysis in a critical event of precipitation, and the weather models BRAMS and ETA were not consistently representative in rainfall estimates in this study. The second part of the results are the calibration of the PM Tank Model that is used on SPEHC. Therefore, it was decided to prepare a series of ten different calibrations for the same region. This fact has been proposed as the principle for the hydrological forecasting analyzes. In the last part of this study, the hydrological forecast were analyzed and it was concluded that all the analyzes regarding the flow prediction is directly linked to the quality of the precipitation. Therefore the hydrological forecast study only analyze the qualitatively results founded and identifying patterns assumed in these graphics. This study concluded that hydrological forecasts are dependent on weather forecasts and all the uncertainties linked to these are passed on modeling flow.

The aim of this master thesis is comparation of simulation tools OptSim™ and PHO- TOSS which are used to create simulations of data traffi cs in access and metropolitan networks. The outcome of this thesis is three laboratory exercises and their theoretical bases which should explain the way of working in diff erent simulation environments to students.

The aim of this master thesis is comparation of simulation tools OptSim™ and PHOTOSS which are used to create simulations of data traffi cs in access and metropolitan networks. The outcome of this thesis is three laboratory exercises and their theoretical bases which should explain the way of working in diff erent simulation environments to students.

This study presents results of selective laser melting (SLM), powder metallurgy (PM), and casting technologies applied for producing Ti–TiB composites from Ti–TiB₂ powder. Diffraction patterns and microstructural investigations reveal that chemical reaction occurred between Ti and TiB₂ during all the three processes, leading to the formation of Ti–TiB composites. The ultimate compressive strength of SLM-processed and cast samples are 1421 and 1434 MPa, respectively, whereas the ultimate compressive strengths of PM-processed 25%, 29%, and 36% porous samples are 510, 414, and 310 MPa, respectively. The Young’s moduli of porous composite samples are 70, 45, and 23 GPa for 25%, 29%, and 36% porosity levels, respectively, and are lower than those of SLM-processed (145 GPa) and cast (142 GPa) samples. Fracture analysis of the SLM-processed and cast samples shows shear fracture and microcracks across the samples, whereas failure of porous samples occurs due to porosities and weak bonds among particles.

Due to growing demands for steel powder properties and continuous evolution of the powder metallurgy (PM) production it is necessary to apply new investigation technics and research applications for quality investigation of the PM products. In addition, it is important to be able to predict the probable maximum size of inclusions. The industrial scale sampling of steel was made in Höganäs AB. The three dimensional (3D) analysis of non-metallic inclusions obtained by electrolytic extraction (EE) method was applied for metal samples taken from liquid steel before water-atomization and after powder forging process. It was demonstrated that the application of the 3D analysis has a perspective and possibility to be used independently or like a reference during 2D analysis of inclusions in powder metallurgy products. The tundish samples have the maximum total number of inclusions but have smaller size of complex inclusion. The size range of inclusions in the ladle and tundish samples is between 1 and 46 μm. The main type of inclusions is spherical (Si-Ca-Al-Mg-O in composition). The powder forged samples have two main types of non-metallic particles: “gray” carbon saturated (10-250 μm) and “bright” clustered oxide particles (1-37 μm with Cr-Si-Mn-Mg-Al-O in composition). The probable maximum size of inclusions was estimated based on a new particle size distribution (PSD) and the standard extreme value distribution (EVD) methods. Both methods predicted that in 1 kg of metal the maximum size of spherical inclusions is &lt; 15 μm in liquid steel samples and the maximum length of “bright” clustered oxide particles is &lt; 63 μm in powder forged samples. However, the prediction of the maximum size by PSD method showed necessity of the further optimization.

<p> Ferritic- Martensitic (F/M) alloys have been used in reactors as cladding steels, wrapper steels. They have Good creep strength, longer lifetimes, less corrosion Powder Metallurgy Hot Isostatic Pressing (PM- HIP) alloys have been suggested as an alternative to be able to improve reactor safety. Gaining a better understanding on how PM-HIP microstructures change under irradiation could make them more viable for widespread use in reactors   </p>

The fine and ultra fine size of diesel particulate mater (DPM) are of great health concern and significantly contribute to the overall cancer risk. In addition, diesel particles may contribute a warming effect on the planet's climate. The composition of these particles is composed principally of elemental carbon (EC) with adsorbed organic compounds, sulfate, nitrate, ammonia, metals, and other trace elements. The purpose of this study was to depict the seasonality and modeling of particulate matter in the Southeastern US produced by the diesel fueled sources (DFSs). The modeling results came from four one-month cases including March, June, September, and December to represent different seasons in 2003 by linking Models-3/CMAQ and SMOKE. The 1999 National Emissions Inventory Version 3 (NEI99) was used in this analysis for point, area, and non-road sources, whereas the National Mobile Inventory Model (NMIM) was used to create the on-road emissions. Three urban areas, Atlanta, Birmingham, and Nashville were selected to analyze the DPM emissions and concentrations. Even though the model performance was not very strong, it could be considered satisfactory to conduct seasonal distribution analysis for DPM. Important hourly DPM seasonality was observed in each city, of which higher values occurred at the morning traffic rush hours. The EC contributions of primary DPM were similar for all three sites (~ 74%). The results showed that there is no significant daily seasonality of DPM contribution to PM2.5 for any of these three cities in 2003. The annual DPM contribution to total PM2.5 for Atlanta, Nashville, and Birmingham were 3.7%, 2.5%, and 2.2%, respectively.