62 research outputs found

    Power conditioning optimization for ultra low voltage wearable thermoelectric devices using self-sustained multi-stage charge pump

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    Waste heat energy recovery from human body utilizing the thermoelectric generator (TEG) has shown potential in the generation of electrical energy. However, the level of heat source from the human body restricts the temperature deviation as compared to ambient temperature (approximately 3~10 °C in difference), thereby yielding an ultra-low voltage (ULV) normally less than 100 mV. This research aims at generating power from the TEG by harnessing human body temperature as the heat source to power up wearable electronic devices realizing a self-sustain system. However, power conversion of the TEG has typically low efficiency (less than 12%), requiring proper design of its power regulation system. The generated ULV marked the lowest energy conversion factor and improvement is therefore required to validate the use of ULV generated from human body temperature. This problem was addressed by proposing an improved solution to the power regulation of the ULV type TEG system based on the DC-DC converter approach, namely a multi-stage charge pump, with specifications restricted at the ULV source. Performances of the TEG connected in multiple array configurations with the generated source voltage fed into fabricated charge pump circuit to boost and regulate the voltage from the ULV into the low voltage (LV) region were analyzed. The maximum source voltage (20 mV) was referred and simulated in the LT Spice software and used as a benchmark to be compared with the voltage generated by the fabricated charge pump circuits. Error performances of the fabricated charge pump circuits were further analyzed by manipulating the circuits’ parameters, namely, the switching frequency and the capacitance values. It was found that the proposed method was able to handle the ULV source voltage with proper tuning on its component parameters. The overall power conversion efficiency of 26.25% was achieved based on the performance evaluation values for components applied in this research. Hence, this proved the viability of thermoelectric applications in ULV using the proposed power regulation system

    Study of the hydrodynamic processes of rivers and floodplains with obstructions

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    A study has been undertaken to supplement design methods and develop innovative approaches for the effective management of rivers and floodplains to reduce flood risk. The focus has been on enhancing the understanding and representation of the hydrodynamic processes of a variety of flow conditions and the associated hydraulic interaction with selected obstruction types, such as mangroves and vehicles for the representative river basins of the Merbok and Klang, on the West Coast of Peninsular Malaysia, and the Valency, near Boscastle, in the UK. For the study of the hydrodynamic processes of natural floodplains, a numerical model has been refined to investigate the effects of mangroves on tsunamis, with the inclusion of modelling idealised test cases. A similar model has then been applied to a mangrove fringed floodplain for the Merbok river basin. In recognising the importance of mangroves as natural defences against flooding disasters, a novel innovative and environmentally friendly approach, namely the Artificial Mangrove Shelter (AMS), has been first initiated and modelled, for the sustainable restoration and rehabilitation of mangroves along floodplains. In studying the hydrodynamic processes of urban floodplains, a series of experimental investigations has been undertaken on stationary scaled model vehicles in laboratory flumes, to study the effects of vehicles on flood flow propagation and, the influence of the flood flows on the stability of the vehicles. In order to develop a useful innovative approach to evaluate the degree of hydraulic stability for vehicles, a novel three colour zone envelope curve has been first introduced and developed, herein known as the Traffic Light of Hydraulic Stability (TLHS), to identify the likelihood of vehicle movement. The study was then extended to investigate the consequential hydraulic impact of flooded vehicles on blocked bridges, through a physical modelling study in a laboratory flume, with the purpose being to replicate a typical section of prototype floodplain conditions for the Boscastle and Klang. In this study, eventually natural and urban environments along the rivers and floodplains have consideration the hydrodynamic processes and interaction between hydraulic obstructions and flood flows, with novel and practical approaches being developed for effective management of rivers and floodplains.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    The State of World Fisheries and Aquaculture 2012

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    The State of World Fisheries and Aquaculture (SOFIA) is the flagship publication of the FAO Fisheries and Aquaculture Department. This premier advocacy document is published every two years to provide policy-makers, civil society and those whose livelihoods depend on the sector a comprehensive, objective and global view of capture fisheries and aquaculture, including associated policy issues

    CIRA annual report 2005-2006

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    Impacts of climate change on fisheries and aquaculture

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    The 2015 Paris Climate Agreement recognizes the need for effective and progressive responses to the urgent threat of climate change, through mitigation and adaptation measures, while taking into account the particular vulnerabilities of food production systems. The inclusion of adaptation measures in the fisheries and aquaculture sector is currently hampered by a widespread lack of targeted analyses of the sector's vulnerabilities to climate change and associated risks, as well as the opportunities and responses available. This report provides the most up-to-date information on the disaggregated impacts of climate change for marine and inland fisheries, and aquaculture, in the context of poverty alleviation and the differential dependency of countries on fish and fishery resources. The work is based on model projections, data analyses, as well as national, regional and basin-scale expert assessments. The results indicate that climate change will lead to significant changes in the availability and trade of fish products, with potentially important geopolitical and economic consequences, especially for those countries most dependent on the sector
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