No description available.

Thesis (M.Sc. (Horticulture)) -- University of Limpopo, 2017 / Tomato is popularly consumed as fresh vegetable or processed product due to its nutritional and health benefits. However, due to its high perishability, tomato cannot be stored for longer duration. Therefore, the aim of this study was the determination of appropriate dipping times into different calcium chloride concentrations to preserve the postharvest quality, storage and the shelf-life of tomato fruit. 'Classic round' tomato fruit were harvested at their pink maturity stage. The experiment was carried out as a completely randomized design (CRD), factorial arranged as 4 × 3 × 8. Treatment factors were: 4 × CaCl2 (0, 0.0045, 0.01 and 0.03%), 3 × dipping times (0, 30 and 60 minutes) and 8 × shelf-life (0 - 7 days). Fruit were stored at 15⁰ C for 30 days, thereafter, held under room temperature for 0 - 7 days of shelf-life while collecting data. During shelf-life period, fruit were evaluated for weight loss, firmness, colour, TSS, TA, pH, physiological and pathological disorders. The interaction between the treatments and dipping times showed a significant effect on weight loss, firmness, colour parameters [L*, b*, chroma and hue angle (⁰)], total soluble solids (TSS), titratable acidity (TA), pH, decay and black mould occurrence. However, significant interactive effects were not shown on a* colour component and chilling injury. In conclusion, calcium chloride (CaCl2) improved the quality and shelf-life of 'Classic round' tomato fruit. Calcium chloride concentration 0.01% was effective at 30 minutes dipping time, meanwhile, 0.03% CaCl2 was effective at 60 minutes dipping time. Therefore, 0.01 and 0.03% can be recommended for commercial preservation use for tomato fruit quality and shelf-life. / Agricultural Research Council-Tropical and Subtropical Crops (ARC-TSC) and National Research Foundation (NRF)

Insect damage in stored maize is one of the major post-harvest losses occurring in developing countries, especially in sub-Saharan Africa. To reduce economic losses, separation of infested grains from clean ones is critical and requires detection of infestation in stored grains. This study aimed at developing a rapid non-destructive detection system with three goals; - the first goal was to investigate the acoustic behavior of internally feeding S. zeamais (Coleoptera: Curculionidae) in maize. The pests were monitored for peak activity and signal amplitudes. The study was performed in the morning, afternoon and night times for three consecutive days with an ultrasonic probe attached to acoustic emission detector. The average number of peaks above threshold in the morning, afternoon and night was significantly different and were 60, 2 and 31 counts/s, respectively (P-value < 0.01). The average maximum amplitude was also different: 2.5, 1 and 1.8V for morning, afternoon and night sessions, respectively. The signal frequencies ranged between 1 and 15 kHz with a peak around 7 kHz. The second goal was to design and develop an inexpensive acoustic device for the detection of S. zeamais in the stored maize. This device included a microphone, signal conditioning circuit and a microcontroller. The third goal was to test the prototype in both clean and infested maize. The device could be manufactured for $55 or less. The device has a noise level below 0.2V in clean maize, infestation amplitude up to 1V and about 93.3% correct detection performance in infected maize. / Master of Science

Present data are insufficient to permit final recommendations as to the best winter-green crop for geese of the sight crops studied. Italian rye grass appears, however, to have very good possibilities because of its good production of forage, its utilization and apparent high preference by geese coupled with a low preference by deer. It is also a relatively inexpensive field crop. Ladino clover is good as a second year crop for both geese and deer besides being economical to plant and maintain, but should be planted early to permit satisfactory first year utilization. Oats, on the refuges on which this investigation was conducted, appears a poor choice because of its high preference by deer and low goose preference. There is a need for additional investigation to permit the accumulation of more conclusive data. Presently reported results reflect limitations which might be overcome with additional investigation. / Master of Science

O presente trabalho apresenta uma discussão de metodologia para o diagnóstico e ações para redução de perdas de água, auxiliando na determinação do perfil das perdas, permitindo uma melhor priorização das ações de combate e redução de perdas reais (físicas) e perdas aparentes (comerciais). Para o desenvolvimento desta metodologia, foi realizada uma ampla revisão bibliográfica, onde é apresentada a conceituação geral sobre perdas de água, suas causas e ocorrências, indicadores, ações para redução, e uma abordagem detalhada quanto às metodologias existentes para avaliação de perdas e ferramentas disponíveis para isto. A metodologia aqui aplicada desenvolve a avaliação das perdas através do balanço hídrico, utilizando o software gratuito desenvolvido pelo Banco Mundial (W-B Easy Calc - v1.17), e foi aplicada no sistema de abastecimento de água da Região Metropolitana de São Paulo (RMSP). Foram levantados os dados básicos de controle do sistema e realizados ensaios de campo, com medições de pressão e ensaios para determinação das perdas aparentes. Como estudo de caso, a metodologia foi aplicada em três setores de abastecimento da área central da RMSP, com características distintas. Os resultados do diagnóstico das perdas foram coerentes com as expectativas. Em função dos resultados, em cada setor deverá ser desenvolvida uma estratégia específica para a redução de perdas. / This study presents a discussion of a methodology for diagnosis and actions to reduce water losses, to assist in determining the profile of water losses, allowing a better prioritization of actions to combat and reduce real (physical) losses and apparent (commercial) losses. For developing the methodology, it was conducted an extensive bibliography review, where is presented the general concepts on water losses, its causes and events, indicators, actions to reduce, and a detailed discussion about the existing methodologies to assess losses and tools available for this. The applied methodology consists of an assessment of losses through the water balance, using free software developed by the World Bank (WB Easy Calc - v1.17) and it was applied in the water supply system in metropolitan region of Sao Paulo. To do this, it was necessary to collect basic data of system control and field tests, with pressure measurements and tests to determine apparent losses. As case study, the methodology was applied in three supply zones at the central area of metropolitan region of Sao Paulo, with different characteristics. The results of water losses diagnosis were consistent with expectations. With these results, a specific strategy should be developed in each sector for reducing losses.

Este trabalho tem por objetivo propor uma nova metodologia para o cálculo das perdas técnicas de energia e demanda por segmento do sistema de distribuição. As perdas técnicas foram divididas em oito segmentos: medidor de energia, ramal de ligação, rede secundária, transformador de distribuição, rede primária, subestação de distribuição, sistema de alta tensão e outros. Neste último segmento, foram incorporadas as parcelas referentes a equipamentos (capacitores, reguladores de tensão, etc), perdas em conexões, corrente de fuga em isoladores, etc. Desenvolveu-se um sistema computacional, para uso em microcomputador, que conta com dois módulos principais. O primeiro módulo destina-se ao cálculo das perdas técnicas em redes específicas. O cálculo é feito de forma hierárquica, por exemplo, selecionada uma subestação específica, são calculadas as perdas na subestação e em todos os componentes a jusante (redes primárias, transformadores de distribuição, redes secundárias, ramais de ligação e medidores de energia). As perdas técnicas, em termos de energia e demanda, são obtidas por meio de cálculo elétrico específico para os segmentos envolvidos, com a utilização dos dados cadastrais da rede, dados de faturamento e curvas de carga típicas por classe de consumidor e tipo de atividade desenvolvida. Com a aplicação deste módulo para todo o sistema da empresa, ou para uma parcela representativa, obtém-se um índice percentual de perda de energia para cada segmento. Estes índices são transferidos para o segundo módulo, que tem por objetivo efetuar o balanço de energia do sistema. A partir dos dados de energia nos pontos de suprimento, da energia total faturada mensalmente e dos índices de perdas por segmento, são obtidos os montantes de energia de perdas em cada segmento do sistema e uma avaliação das perdas não técnicas. O trabalho ainda apresenta um exemplo de aplicação, em sistema de distribuição real, mostrando os resultados obtidos, e termina apresentando as principais vantagens da metodologia. Os resultados obtidos com a nova metodologia são comparados com os resultados obtidos com outras metodologias. / This work focuses on the development of a new methodology for calculating technical losses within the different segments of the electric distribution system. In order to evaluate technical losses the electrical system was divided into eight segments: energy meter, customer connections, secondary feeder, distribution transformer, primary feeder, distribution substation, high voltage system and another segment that represents other technical losses. The latter comprises losses in equipment such as capacitors and voltage regulators as well as losses in electric connections, isolators, etc. A computational system was developed and it comprises two modules. The first one is intended to calculate technical losses in specific networks. The calculation is made in a hierarchical manner. If a distribution substation is selected for the calculation, the losses in that substation and the losses in all components downstream are calculated. The technical losses, in terms of energy and demand, are obtained by utilizing network topological data, consumed energy data and typical load curves per customer class and activity type. An energy losses index, calculated as a percentage of the supplied energy, is obtained for each segment by applying this module to the entire utility’s power system or in a representative part of it. These values are transferred to the second module, which has the objective of determining the overall energy balance. Technical and non-technical losses, in terms of energy, in each segment are obtained by utilizing the total amount of energy supplied to the system, energy consumed and energy losses indices per segment. This work shows the results obtained by applying the computational tool to a real distribution system. Such results are compared with the ones obtained by using other methodologies, and the main advan ages of this new methodology are outlined.

O presente trabalho apresenta uma discussão de metodologia para o diagnóstico e ações para redução de perdas de água, auxiliando na determinação do perfil das perdas, permitindo uma melhor priorização das ações de combate e redução de perdas reais (físicas) e perdas aparentes (comerciais). Para o desenvolvimento desta metodologia, foi realizada uma ampla revisão bibliográfica, onde é apresentada a conceituação geral sobre perdas de água, suas causas e ocorrências, indicadores, ações para redução, e uma abordagem detalhada quanto às metodologias existentes para avaliação de perdas e ferramentas disponíveis para isto. A metodologia aqui aplicada desenvolve a avaliação das perdas através do balanço hídrico, utilizando o software gratuito desenvolvido pelo Banco Mundial (W-B Easy Calc - v1.17), e foi aplicada no sistema de abastecimento de água da Região Metropolitana de São Paulo (RMSP). Foram levantados os dados básicos de controle do sistema e realizados ensaios de campo, com medições de pressão e ensaios para determinação das perdas aparentes. Como estudo de caso, a metodologia foi aplicada em três setores de abastecimento da área central da RMSP, com características distintas. Os resultados do diagnóstico das perdas foram coerentes com as expectativas. Em função dos resultados, em cada setor deverá ser desenvolvida uma estratégia específica para a redução de perdas. / This study presents a discussion of a methodology for diagnosis and actions to reduce water losses, to assist in determining the profile of water losses, allowing a better prioritization of actions to combat and reduce real (physical) losses and apparent (commercial) losses. For developing the methodology, it was conducted an extensive bibliography review, where is presented the general concepts on water losses, its causes and events, indicators, actions to reduce, and a detailed discussion about the existing methodologies to assess losses and tools available for this. The applied methodology consists of an assessment of losses through the water balance, using free software developed by the World Bank (WB Easy Calc - v1.17) and it was applied in the water supply system in metropolitan region of Sao Paulo. To do this, it was necessary to collect basic data of system control and field tests, with pressure measurements and tests to determine apparent losses. As case study, the methodology was applied in three supply zones at the central area of metropolitan region of Sao Paulo, with different characteristics. The results of water losses diagnosis were consistent with expectations. With these results, a specific strategy should be developed in each sector for reducing losses.

Este trabalho tem por objetivo propor uma nova metodologia para o cálculo das perdas técnicas de energia e demanda por segmento do sistema de distribuição. As perdas técnicas foram divididas em oito segmentos: medidor de energia, ramal de ligação, rede secundária, transformador de distribuição, rede primária, subestação de distribuição, sistema de alta tensão e outros. Neste último segmento, foram incorporadas as parcelas referentes a equipamentos (capacitores, reguladores de tensão, etc), perdas em conexões, corrente de fuga em isoladores, etc. Desenvolveu-se um sistema computacional, para uso em microcomputador, que conta com dois módulos principais. O primeiro módulo destina-se ao cálculo das perdas técnicas em redes específicas. O cálculo é feito de forma hierárquica, por exemplo, selecionada uma subestação específica, são calculadas as perdas na subestação e em todos os componentes a jusante (redes primárias, transformadores de distribuição, redes secundárias, ramais de ligação e medidores de energia). As perdas técnicas, em termos de energia e demanda, são obtidas por meio de cálculo elétrico específico para os segmentos envolvidos, com a utilização dos dados cadastrais da rede, dados de faturamento e curvas de carga típicas por classe de consumidor e tipo de atividade desenvolvida. Com a aplicação deste módulo para todo o sistema da empresa, ou para uma parcela representativa, obtém-se um índice percentual de perda de energia para cada segmento. Estes índices são transferidos para o segundo módulo, que tem por objetivo efetuar o balanço de energia do sistema. A partir dos dados de energia nos pontos de suprimento, da energia total faturada mensalmente e dos índices de perdas por segmento, são obtidos os montantes de energia de perdas em cada segmento do sistema e uma avaliação das perdas não técnicas. O trabalho ainda apresenta um exemplo de aplicação, em sistema de distribuição real, mostrando os resultados obtidos, e termina apresentando as principais vantagens da metodologia. Os resultados obtidos com a nova metodologia são comparados com os resultados obtidos com outras metodologias. / This work focuses on the development of a new methodology for calculating technical losses within the different segments of the electric distribution system. In order to evaluate technical losses the electrical system was divided into eight segments: energy meter, customer connections, secondary feeder, distribution transformer, primary feeder, distribution substation, high voltage system and another segment that represents other technical losses. The latter comprises losses in equipment such as capacitors and voltage regulators as well as losses in electric connections, isolators, etc. A computational system was developed and it comprises two modules. The first one is intended to calculate technical losses in specific networks. The calculation is made in a hierarchical manner. If a distribution substation is selected for the calculation, the losses in that substation and the losses in all components downstream are calculated. The technical losses, in terms of energy and demand, are obtained by utilizing network topological data, consumed energy data and typical load curves per customer class and activity type. An energy losses index, calculated as a percentage of the supplied energy, is obtained for each segment by applying this module to the entire utility’s power system or in a representative part of it. These values are transferred to the second module, which has the objective of determining the overall energy balance. Technical and non-technical losses, in terms of energy, in each segment are obtained by utilizing the total amount of energy supplied to the system, energy consumed and energy losses indices per segment. This work shows the results obtained by applying the computational tool to a real distribution system. Such results are compared with the ones obtained by using other methodologies, and the main advan ages of this new methodology are outlined.

The main goal of this thesis is a determination of an idle stray losses in induction machine and creation calculation program in MATLAB. The stray losses are caused especially by the eddy currents on the surface of stator and rotor, further by a pulsation of these currents owing to the periodical change of air-gap permeance, magnetic induction in stator and rotor teeth and a differential leakage. Value of stray losses are different of engine construction especially by it are scoring insulated, uninsulated, straight or slant.

Ungefär en fjärdedel av den klimatpåverkan som de svenska hushållen orsakar kommer från maten vi äter, eller närmare bestämt från de utsläpp av växthusgaser som maten ger upphov till på sin väg från jord till bord. Om maten slängs innan den konsumeras har denna miljöpåverkan skett i onödan. Uppsatsen undersöker VIS (Välgörenhet Istället för Svinn), en svinnåtgärd där fullvärdiga livsmedel istället för att slängas, skänks till välgörenhet. Målet är att undersöka hur VIS fungerar, samt att bidra till ökade kunskaper om detta för Sverige nya sätt att bemöta svinnproblematiken. VIS styrkor och svagheter, liksom de hot och möjligheter som kan finnas, har undersökts med hjälp av en SWOT-analys. Uppsatsen utgår ifrån företaget Allwin i Göteborg, en av få som professionellt arbetar med VIS i Sverige idag. Studien är kvalitativ och utgår från sex semistrukturerade intervjuer med Allwin och deras samarbetspartners. Uppsatsens resultat kan sammanfattas i fem slutsatser: 1) Att skänka livsmedel, med hjälp av svinnåtgärden VIS, innebär att nya värdekedjor skapas. 2) En professionalisering av VIS/Allwin har ökat förutsättningarna för en långsiktigt hållbar svinnåtgärd. 3) VIS/Allwin är pionjärer och drabbas av de svårigheter det innebär att trampa upp nya stigar. 4) Efterfrågan på VIS/Allwins tjänster kommer med all sannolikhet att öka. 5) VIS är en komplex åtgärd som kräver ett tydligt engagemang från alla inblandade parter, det finns därmed risk för att enklare lösningar prioriteras. / About a fourth of the climate impact originating from Swedish households can be derived from food, or rather from emissions caused in different stages of food production from field to fork. If food is being thrown away instead of being consumed the environmental impact has been in vain. The essay investigates CIW (Charity Instead of Waste, in Swedish VIS), a measure to deal with food losses where food is given to charity instead of becoming waste. The aim is to investigate how CIW functions and to contribute to increased knowledge on this, in Sweden, new way of responding to the problem with food losses. The strengths and weaknesses of CIW as well as the threats and opportunities that might be, have been examined by a SWOT-analysis. The company Allwin in Gothenburg is the concrete example of CIW that the essay is based on. The essay is a qualitative study with its starting point in six semi structured interviews with representatives from Allwin and its partners. The results of the essay can be summarized in five conclusions: 1) Donating food using CIW means that new value chains are created. 2) Allwin has gone from being a nonprofit organization to being a company. This professionalization has improved the conditions for making CIW a long term sustainable measure to deal with food losses. 3) CIW/Allwin are pioneers and have to deal with many difficulties related to breaking new ground. 4) The demand for services from CIW/Allwin is most likely to increase. 5) CIW is a complex measure, which requires a lot of engagement from all involved partners. This suggesting a risk that easier solutions could be prioritized.