Thesis (M. Sc.)--University of Hong Kong, 1999. / Includes bibliographical references.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Small-scale farmers have the opportunity to gain access to markets through a contract farming arrangement. The key question is whether it is financially feasible for a small-scale farmer to enter into a contract. The objectives of this study were to develop a model that could be used to determine the financial feasibility of small-scale contract broiler farming in an intensive production system, compare three different genotypes namely: Cobb500 males X Hybro G females, Ross 308 males X Potchefstroom Koekoek females (crossbred) and the purebred Potchefstroom Koekoek, and evaluate current smallscale farmers’ broiler production by means of a case study. Financial performance indicators such as the net present value, cash flow and profit and loss statements were used to analyze the feasibility of all the scenarios. The model was built in Microsoft Excel. Five hundred, 1500 and 2500 birds/cycle scale of production were analyzed. Results revealed that based on the capital costs used, a 500 birds/cycle scale of production was uneconomical and that a farmer would have to receive R25.01/kg broiler meat in order to break even. The 1500 scale of production showed much better results. A farmer could break even at R17.51/kg meat. The capital investment cost of the 2500 scale of production was so high that the farmer would have had to sell his broiler meat for R18.54/kg. Performance traits of genotypes were collected through an experiment and data was statistically analyzed using ‘Statistica 9’. Results showed that there were significant differences between the cumulative feed intake, feed conversion ratios and the European production efficiency ratio of the different genotypes. No significant difference was found in the liveability of the genotypes. Data on performance traits was used as input into the model so that the economic feasibility of the genotypes could be compared. Results showed that a purebred Potchefstroom Koekoek genotype was not suitable for an intensive production system and that the crossbreed did not perform as well as the broiler breed, but that it would be worthwhile investigating the performance traits of the cross breed under less optimal conditions or in a free-range system. The lower capital costs necessary for a freerange system, together with the high premium paid for free-range broiler meat, may give admirable results in the economic feasibility of a small-scale broiler farm. / AFRIKAANSE OPSOMMING: Kleinboere het die geleentheid om deur kontrak boerdery toegang tot markte te verkry. Die vraag is egter of dit finansieël haalbaar is vir 'n kleinboer om kontraktueel verbind te word? Die doelwitte van die studie was om: ‘n model te ontwikkel wat gebruik kan word om die finansiële lewensvatbaarheid van' n klein-skaalse braaikuikenboer te bepaal onder 'n intensiewe produksiestelsel; verskillende genotipes naamlik: Cobb500 hane X Hybro G henne, Ross 308 hane X Potchefstroom Koekoek henne (kruising) en die suiwer Potchefstroom Koekoek te evalueer en die die huidige klein-skaal boer se braaikuikenproduksie deur middel van 'n gevallestudie te evalueer. Finansiële prestasie aanwysers soos die netto huidige waarde, kontantvloei, asook wins en verlies state was gebruik om die haalbaarheid van die verskeie gevalle te analiseer. Die model is op Microsoft Excel gebou. ‘n Produksie skaal van 500, 1500 en 2500 kuikens/siklus is ontleed. Resultate het getoon dat, gebaseer op die kapitale koste wat gebruik is, 'n produksie skaal van 500 kuikens/siklus onekonomies is en dat ʼn boer R25.01/kg sal moet ontvang om gelyk te breek. Die produksie skaal van 1500 kuikens/siklus het beter resultate getoon. 'n Boer kan gelyk breek teen R17.51/kg vleis. Die kapitale beleggingskoste van die produksie skaal van 2500 kuikens/siklus was so hoog dat die boer R18.54/kg sou moes ontvang het om gelyk te breek. Prestasie van genotipes is ingesamel deur middel van 'n eksperiment en data is statisties ontleed met behulp van Statistica 9. Resultate het getoon dat daar hoogs beduidende verskille tussen die kumulatiewe voerinname, voeromsetsverhoudings en Europese produksie effektiwiteits verhouding van die verskillende genotipes is. Geen beduidende verskil is gevind in die leefbaarheid van die genotipes nie. Inligting oor die prestasie eienskappe is gebruik as insette tot die model sodat die ekonomiese haalbaarheid van die genotipes vergelyk kon word. Resultate het getoon dat 'n suiwer Potchefstroom Koekoek genotipe nie geskik is vir 'n intensiewe produksie stelsel nie en dat die kruising nie so goed soos die braaikuiken gevaar het nie, maar dat dit die moeite werd sal wees om ondersoek in te stel na die produksie potensiaal van die kruis kuiken in minder optimale toestande, soos ‘n vryloop stelsel. Die laer kapitale koste en die hoë premie wat betaal word vir vryloop braaikuikenvleis mag geloofwaardige resultate op die ekonomiese haalbaarheid van 'n kleinskaalse braaikuikenboer toon.

Sachsen bekommt eine neue Videoplattform – den Videocampus Sachsen (VCS). Durch das Sächsische Ministerium für Wissenschaft und Kunst (SMWK) wurde Ende 2017 das Projekt zur Umsetzung genehmigt. Im Rahmen der Pilotphase 2018 erfolgt die Konstituierung eines sächsischen Verbundes wie auch die An- und Einpassung der Plattform in die gemeinsame technische Infrastruktur der sächsischen Hochschulen. Ab 2019 soll das Videoportal dann durch den Dienstleister BPS GmbH in den Regelbetrieb überführt werden. Bis hierhin war es ein langer Weg. Der vorliegende Sammelband dokumentiert die Schritte dorthin. Auf den folgenden Seiten werden zentrale Ergebnisse der 2015/16 erstellten, kumulativen Machbarkeitsuntersuchung zur Einrichtung eines hochschulübergreifenden sächsischen Videoportals vorgestellt.

Introduction: Breastfeeding offers the substance exposed mother and child potential short and long-term health benefits, with breast milk shown to alleviate the severity of Neonatal Abstinence Syndrome. Substance dependent women, however, have limited success establishing breastfeeding with physical, psychological and institutional factors cited as barriers. This study aimed to develop and test the feasibility of an evidence informed and theory based intervention to support continued breastfeeding for this group. Methods: The research was a two-phase feasibility study. Phase 1 informed intervention development using a mixed methodology approach which included (a) a comprehensive systematic literature review of breastfeeding support for women from disadvantaged groups (b) expert advisory group recommendations and (c) ‘think aloud’ verbal protocols with opioid dependent women. Phase 2 underpinned the evidence with the theoretical constructs of behaviour change, prior to testing the acceptability and implementation fidelity of the intervention in a feasibility study with an embedded small-scale randomised controlled trial. Results: Phase 1 identified the barriers to breastfeeding continuation as low maternal self-efficacy; neonatal feeding difficulties associated with withdrawal and unsupportive healthcare practices. Evidence and theory synthesis resulted in an integrated breastfeeding support model founded on practical, informational, psychological, person-centred and environmental components. Phase 2 demonstrated that the intervention was feasible to implement and acceptable to participants. The randomised controlled trial reported higher rates of continued breastfeeding and a greater level of maternal confidence in breastfeeding ability in the intervention group compared to the control group. Breastfed infants were less likely to require pharmacological management and had corresponding shorter durations of hospitalisation than formula fed infants. Conclusion: The research provided an original contribution to the development of a complex healthcare intervention which is meaningful to both existing research and clinical practice. The findings highlighted the potential of the intervention to support breastfeeding for the substance exposed mother and baby, which has wide ranging implications for the improved health and social equalities of this group.

Magister Philosophiae - MPhil / South Africa

The solar PV modules are influenced by a variety of loss mechanisms by which the energy yield is affected. A PV system is the sum of individual PV modules which should ideally operate similarly, however, inhomogeneous soiling, mismatching, and degradation, which are the main focus in this study, lead to dissimilarities in PV modules operating behavior and thus, lead to losses which will be assessed intensively in terms of energy yield. The dissimilarities in PV modules are referred to the ambient conditions or the PV modules characteristics which result in different modules’ maximum power point (MPP) and thus, different currents generated by each PV modules which cause the mismatching. However, the weakest PV module current governs the string current, and the weakest string voltage governs the voltage. Power optimizers are electronic devices connected to the PV modules which adjust the voltages of the PV modules in order to obtain the same current as the weakest module and thus, extract the modules’ MPP. Hence, the overall performance of the PV plant is enhanced. On the other hand, the power optimizers add additional cost to the plant’s investment cost and thus, the extra energy yield achieved by utilizing the power optimizers must be sufficient to compensate the additional cost of the power optimizers. This is assessed by designing three systems, a reference system with SMA inverters, a system utilizes Tigo power optimizers and SMA inverters, and a system utilizes SolarEdge power optimizers and inverters. The study considers four different locations which are Borlänge, Madrid, Abu Dhabi, and New Delhi. An Excel model is created and validated to emulate the inhomogeneous soiling and to evaluate the economic feasibility of the power optimiz ers. The model’s inputs are obtained from PVsyst and the precipitation data is obtained from Meteoblue and SMHI database. The economic model is based on the relation between Levelized Cost of Electricity (LCOE) which will be used to derive the discount rate. Graphs representing the discounted payback period as a function of the feed-in tariff for different discount rates is created in order to obtain the discounted payback period. The amount of extra energy yielded by the Tigo and the SolarEdge systems is dependent on the soiling accumulated on the PV modules. Relative to the reference system, 6.5 % annual energy gain by the systems utilizing the power optimizers in soiling conditions, up to 2.1 % in the degradation conditions, and up to 9.7 % annual energy gain at 10 % mismatching rate. The extra energy yield is dependent on the location, however, the Tigo and the SolarEdge systems have yielded more energy than the reference system in all cases except one case when the mismatch losses is set to zero. The precipitation pattern is very influential, and a scare precipitation leads to a reduction in the energy yield, in this case, the Tigo and the SolarEdge systems overall performance is enhanced and the extra energy gain becomes greater. The Tigo system yield slightly more energy than the SolarEdge system in most cases, however, during the plant’s lifetime, the SolarEdge system could become more efficient than the Tigo system which is referred to the system’s sizing ratio. The degradation of the system or the soiling accumulation decreases the irradiation and thus, a slightly oversized PV array become suitable and deliver an optimal power to the inverters. The SolarEdge system is feasible in all scenarios in terms of LCOE and discounted payback period, although its slightly lower performance relative to the Tigo system, this is referred to its low initial cost in comparison to the other systems. The Tigo system is mostly infeasible although it yields more energy than the reference and the SolarEdge systems, this is referred iii to its relatively high initial cost. However, feed- in tariffs higher than 20 € cent / kWh make all systems payback within less than 10 years. The results have overall uncertainty within ± 6.5 % including PVsyst, Excel model, and the precipitation uncertainties. The uncertainty in the degradation and the mismatching calculations is limited to PVsyst uncertainty which is ± 5 %. The uncertainties in LCOE in the location of New Delhi, since it is the worst-case scenario, are 5.1 % and 4 % for the reference and the systems utilizing power optimizers, respectively. Consequently, accommodating the uncertainties to the benefits gained by utilizing power optimizers indicates that the energy gain would oscillate in the range of 6 % - 6.9 % for the soiling calculations, 2 % - 2.2 % for the degradation simulations, and 9.2 % - 10.2 % for the mismatching simulations at 10 % mismatchrate.

O elevado consumo energético de edificações para o seu condicionamento térmico já é um dos maiores impactos ambientais da construção civil nos países desenvolvidos e, progressivamente, vem se tornando uma preocupação também nos países em desenvolvimento. Uma alternativa renovável relativamente recente, tanto para aquecimento como para resfriamento, são as bombas de calor geotérmicas (ground source heat pumps, GSHPs), que se valem da inércia térmica do solo para reduzir significativamente a demanda energética em relação ao ar. Apesar do seu grande potencial em reduzir o consumo de energia e as emissões de carbono, esta tecnologia ainda é quase inexistente na América Latina, não somente devido à falta de conhecimento ao seu respeito, mas também pela incerteza quanto à sua viabilidade frente a um custo inicial mais elevado. Embora existam muitas pesquisas sobre o funcionamento de GSHPs, grande parte do conhecimento prático quanto ao projeto, desempenho e viabilidade é baseada na experiência dos primeiros países onde a tecnologia começou a se tornar popular, e não pode ser assumida automaticamente como válida em outras situações sem uma avaliação prévia Estudos anteriores apontaram que o retorno econômico de GSHPs tende a ser maior em climas mais frios, enquanto a eficiência tende a ser maior em climas mais amenos, mas com sazonalidade. Por apresentar um bom balanço destas características, o Estado do Rio Grande do Sul apresenta potencial para um desempenho elevado de GSHPs. O objetivo deste trabalho é estimar os níveis de eficiência que esta tecnologia pode atingir em uma cidade de referência no Estado, assim como seu retorno econômico frente a ASHPs (air source heat pumps, ou seja, aparelhos de ar condicionado, ou A/C), seus limitantes e as dificuldades de projeto. Uma edificação unifamiliar residencial em Porto Alegre, projetada especialmente para estudos de sustentabilidade, foi utilizada como caso de estudo para o projeto conceitual completo de um GSHP vertical, um GSHP horizontal e um ASHP. Foram estimadas a demanda de energia e os custos de operação e de implantação para determinadas condições, que foram comparadas em um estudo de viabilidade econômica. Após, os resultados foram extrapolados por uma análise de sensitividade para condições mais genéricas de consumo. Através dos cálculos, observou-se que a tecnologia de GSHPs atingiu o dobro da eficiência dos A/C mais eficientes disponíveis para o caso de estudo. Economicamente, a tecnologia também se mostrou viável, e foram estimados limitantes econômicos a esta viabilidade. Por fim, o processo de projeto desenvolvido pode servir de auxílio a novos projetistas na área. / The high energy consumption in buildings for their thermal conditioning is already one of the greatest environmental impacts of civil construction in developed countries and, progressively, is also becoming a concern in the developing countries. A relatively recent renewable alternative, as much for heating as for cooling, are the ground source heat pumps, GSHPs, which take advantage of the thermal inertia of the ground to significantly decrease the energy demand comparing to air as a source. In spite of their huge potential for decreasing energy comsumption and carbon emissions, this technology is still almost inexistent in Latin America, due not only to lack of awareness, but mainly to uncertainties about their feasibility because of their higher investment cost. Although there are many researches about the characteristics and operation of GSHPs, great part of the practical knowledge as to the design, performance and feasibility is based in the experience from the first countries where the technology spreaded, and cannot be automatically assumed as valid without a previous evaluation. Former studies indicated that the economic profit of GSHPs tends to be higher in colder climates, while the efficiency tends to be higher in milder, but still seasonal climates. For presenting a good balance among these factors, the Rio Grande do Sul State shows potential for a high performance of GSHPs The objective of this work is to estimate the efficiency levels that can be reached by this technology in a reference city in the State, as its financial feedback compared to ASHPs (air source heat pumps, the traditional air conditioners, or A/C), its limitations and the design difficulties. A residential single-family building in Porto Alegre, specifically designed for sustainability studies, was used as case study for the complete conceptual design of a vertical GSHP, a horizontal GSHP and an ASHP. The energy demand and operation and installation costs for specific conditions were estimated and compared in a economic feasibility study. After, the results were extrapolated through a sensitivity analysis for more generic situations of consumption. Through the calculations, it was observed that the technology achieved twice the efficiency of the most efficient A/C available for the case study. Economically, the technology showed itself viable, and economic limitations were also estimated. At last, the developed design process can also serve as aid to new designers in the field.

Made available in DSpace on 2014-06-11T19:22:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-03Bitstream added on 2014-06-13T18:49:31Z : No. of bitstreams: 1 guimaraes_rfa_me_ilha.pdf: 2262303 bytes, checksum: 5b02ef57986a43b0710df7b64c4e2056 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A proposta deste trabalho é analisar o comportamento de transformadores de distribuição trifásicos após a recuperação estudando suas perdas elétricas fixas e variáveis tomando-se o transformador como uma unidade consumidora para demonstrar a viabilidade econômica da reforma, principalmente àquelas que não alteram o núcleo. Foram utilizados os ensaios de rotina de uma empresa recuperadora para uma importante concessionária de distribuição de energia. Este trabalho também faz uma recomendação sobre o descarte deste material segundo conceitos ambientais para uma melhor utilização dos recursos naturais. É importante mencionar o fato que muitos dos transformadores analisados operam a mais de 20 anos. A recuperação permite as concessionárias fornecer energia elétrica para consumidores residenciais e rurais de baixa renda mediante um pequeno investimento na construção de novas linhas de distribuição / The purpose of this paper is to analyze the behavior of three-phase distribution transformers when submitted to recovery, taking into consideration fixed and variable electric losses considering the transformer as a consumer unit to demonstrate the economical feasibility, especially those that do not modify the core. It has been used routine tests data obtained from a company that recover for an important power deliver. This paper also deals with the disposal of the material considering environmental concerns, for a better use of natural resources. It is important to mention the fact that many transformers have already operated for more than 20 years. The recover allows the deliver to provide energy to residential or rural low-income consumer through a low investment with the construction of new electric power grid

Made available in DSpace on 2014-06-11T19:24:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-12Bitstream added on 2014-06-13T19:52:16Z : No. of bitstreams: 1 quintana_nrg_me_botfca.pdf: 988588 bytes, checksum: da5688f095d40118648d17687e9019c9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Neste estudo avaliou-se a dose economicamente adequada de lodo de esgoto (base seca) proveniente da ETE/Barueri empregada na cultura do milho. Para a obtenção dos dados, utilizaram-se relatórios gerados pela UNESP/Jaboticabal referente ao experimento realizado naquela unidade. A partir desses foram constituídas matrizes econômicas para quatro tratamentos, seguindo modelo de custos de produção do IEA/SAASP. O experimento, no qual este estudo baseou-se, foi instalado em Latossolos Vermelhos distrófico e eutroférrico, durante seis anos, sendo no primeiro ano adotado o cultivo convencional, posteriormente substituído por cultivo mínimo. Quatro tratamentos para os 2 tipos de solos (blocos casualizados; n = 5) foram realizados: T, sem fertilização no primeiro ano, e fertilização mineral nos anos subseqüentes; D1, aplicação de 2,5 t ha-1 de lodo de esgoto (base seca), nos três primeiros anos; substituída por 20,0 t ha-1 nos anos seguintes; D2, 5,0 t ha-1 de lodo de esgoto; D3, 10,0 t ha-1 de lodo de esgoto. Quando necessário, houve complementação mineral nos tratamentos D1 a D3. Para análise dos dados do presente estudo, o experimento foi dividido em duas fases: a primeira, anos 2 e 3, e a segunda, os três últimos anos, sendo cada ano considerado um bloco, devido alteração na dose em D1. Apenas os 2 dados da segunda fase foram considerados nas análises posteriores. Os dados foram comparados por análise de variância complementada por teste de Tukey e regressão quadrática (x=dose de lodo de esgoto e y=rentabilidade) para cada solo e rentabilidade (P<0,05). Além disso, calculou-se a distância máxima eficiente de transporte do lodo de esgoto, considerandose o custo do transporte pago pela geradora do resíduo ou pelos agricultores que o utilizam. Observou-se que a rentabilidade diferiu somente para as doses de lodo de esgoto. Obteve-se diferença... / In this study, it was assessed an economically feasible dose of sewage sludge (dry matter basis) from ETE/Barueri in sweet-corn culture. Data were obtained from reports of a previous experiment conducted in UNESP/ Jaboticabal (described below). It was composed worksheets concerning economical data for each treatment following a production trade-off template from IEA/SAASP. The experiment, wherein this study was based on, was performed on haplustox (RED LATOSSOL) and RED LATOSSOL typical eutrophyc, for about six years, divided into conventional cultivation just in the first year, and subsequently replaced by minimum cultivation. Four treatments took place for the 2 kinds of soil (two-way anova design; n = 5): T, no fertilizer added in the first year, and mineral fertilizing subsequently; D1, 2.5 t ha-1 of sewage sludge in the first three years; replaced by 20.0 t ha-1 subsequently; D2, 5.0 t ha-1 de sewage sludge; D3, 10.0 t ha-1 of sewage sludge; soil mineral enrichment was done when necessary for both D1 to D3 treatment. For data analysis of the present study, the experiment was divided into two phases: first one, comprising year 2 and 3, while second phase the last three years, each year was considered an experimental block, it was made due to alteration in the used dose for D1, however data of second phase only were considered for further analysis. Data were evaluated by ANOVA and post hoc compared by Tukey test, and quadratic regression (x = sewage sludge dose and y = yield) for each soil and yield (P<0.05). Moreover, it was calculated the maximum efficient distance for sewage sludge transportation, for this it was considered the cost for transporting spent by the generating source or by farmers who has used sewage sludge. Results indicate that yield was different just for sewage sludge dose. It was obtained statistical difference among control treatment and the 4 others... (Complete abstract click electronic access below)

Made available in DSpace on 2014-10-09T12:47:30Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:22Z (GMT). No. of bitstreams: 1 08988.pdf: 8668818 bytes, checksum: e0f5fe180edb5cadb275182177aa753d (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP