39 resultados para occupation store
em Universidade do Minho
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The MAP-i doctoral program of the Universities of Minho, Aveiro and Porto
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Dissertação de mestrado integrado em Engenharia e Gestão de Sistemas de Informação
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Dissertação de mestrado em Ensino de Biologia e Geologia no 3º Ciclo do Ensino Básico e no Ensino Secundário
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One of the biggest challenges for urban space planners is to conciliate the indispensable demands of life with the forms of occupation of the territory. Among these demands is water. Population growth and urban sprawl are challenging water availability. Thus, it is important to evaluate development trends to predict future scenarios, enabling guide preventive actions and decision making. It is essential to have a practical and direct tool that allows us to transmit the necessary information. The objective of this study is to present a method for evaluating the urban efficiency in the process of city expansion and the availability of water supply. To do so, the indicators will be defined, called indicators of "hidricidade". As a result, it is expected to be obtained a direct and practical tool, that is going to allow to transmit the necessary information to the harmonic urban process planning, applicable to medium size Brazilian cities, allowing decision making as a guarantee of water supply and urban sprawl.
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Dissertação de mestrado em Construção e Reabilitação Sustentáveis
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Studies in Computational Intelligence, 616
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This paper presents the development of the power electronics needed for the interaction between the electrical generator of a wind turbine and an isolated ac micro grid. In this system there are basically two types of receptors for the energy produced by the wind turbine, which are the loads connected to the isolated micro grid and the batteries used to store energy. There are basically two states in which the system will work. One of the states is when there is enough wind power to supply the loads and the extra energy is used to charge the batteries. The other state is when there is low wind power and the batteries have to compensate the lack of power, so that the isolated micro grid has enough power to supply at least the priority loads. In this paper are presented the hardware and the control algorithm for the developed system. The topology was previously tested in computer simulations, using the software PSIM 9.0, and then validated with the implementation of a laboratory prototype.
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The MAP-i Doctoral Programme in Informatics, of the Universities of Minho, Aveiro and Porto
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Companies and researchers involved in developing miniaturized electronic devices face the basic problem of the needed batteries size, finite life of time and environmental pollution caused by their final deposition. The current trends to overcome this situation point towards Energy Harvesting technology. These harvesters (or scavengers) store the energy from sources present in the ambient (as wind, solar, electromagnetic, etc) and are costless for us. Piezoelectric devices are the ones that show a higher power density, and materials as ceramic PZT or polymeric PVDF have already demonstrated their ability to act as such energy harvester elements. Combinations between piezoelectric and electromagnetic mechanism have been also extensively investigated. Nevertheless, the power generated by these combinations is limited under the application of small magnetic fields, reducing the performance of the energy harvester [1]. In the last years the appearance of magnetoelectric (ME) devices, in which the piezoelectric deformation is driven by the magnetostrictive element, enables to extract the energy of very small electromagnetic signals through the generated magnetoelectric voltage at the piezoelectric element. However, very little work has been done testing PVDF polymer as piezoelectric constituent of the ME energy harvester device, and only to be proposed as a possibility of application [2]. Among the advantages of using piezopolymers for vibrational energy harvesting we can remember that they are ductile, resilient to shock, deformable and lightweight. In this work we demonstrate the feasibility of using magnetostrictive Fe-rich magnetic amorphous alloys/piezoelectric PVDF sandwich-type laminated ME devices as energy harvesters. A very simple experimental set-up will show how these laminates can extract energy, in amounts of μW, from an external AC field.
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Maize (Zea mays) and guinea corn (Sorghum bicolor) are major food items in Plateau state, Nigeria. A multistage sampling technique was used to select the markets and store/warehouses used for this study; sample collection employed a simple random sampling method from different sampling points within designated areas. A total of 18 representative samples were collected and analyzed for the following mycotoxins: aflatoxins (Aflatoxin B1 - AFB1, Aflatoxin B2 - AFB2, Aflatoxin G1 - AFG1 and Aflatoxin G2 - AFG2), fumonisins (Fumonisin B1 - FB1 and Fumonisin B2 - FB2 ) and cyclopiazonic acid (CPA). Out of 12 samples analyzed for Aflatoxins, AFB1 was detected in 5, AFB2 in 1, AFG1 in 1 and AFG2 in 6 samples respectively. The highest concentration of AFB1 and AFG2 were found in maize samples from Pankshin market. Only maize samples from Mangu market were contaminated with AFB2 and also harboured the lowest concentration of AFG2. AFG1 contamination occurred in only guinea corn from Shendam market. and FB1 was detected in all 18 samples analyzed. The mycotoxin CPA was not detected in any of the samples. Aflatoxins levels in analyzed samples were regarded as safe based on Nigerian and European Union maximum permissible levels of 4g/kg. With the exception of two samples, FB1 levels in analyzed maize samples were within European Union maximum permissible levels of 1,000 to 3000g/kg. The health and food safety implications of these results for the human and animal population are further discussed.
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Dissertação de mestrado em Engenharia Industrial
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Dissertação de mestrado integrado em Arquitectura
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Dissertação de mestrado integrado em Engenharia e Gestão Industrial
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Dissertação de mestrado em Engenharia Industrial