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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Impact of Land Management Practices on Water Balance and Sediment Transport in the Morogoro Catchment, Uluguru Mountains (Tanzania)

Kilemo, Dominico Benedicto 15 February 2018 (has links) (PDF)
Tanzania, like other developing countries in the tropics is severely affected by the degradation of water resources owing to improper land management practices. Such practices affect water supply through soil erosion which does not only cause sedimentation of rivers and water bodies but also leads to a reduction in the rainwater infiltration capacity of soils. This thesis seeks to demonstrate how the implementation of proper land management measures can reduce soil erosion and increase water supply in the Morogoro River catchment (Uluguru Mountains). The proper practices referred to are the soil and water conservation (SWC) approaches which include contour farming, fanya juu terracing and bench terracing. The thesis combines social science and geoscience methods in a synergetic manner to address this research problem. To understand how and to what degree SWC methods affect water fluxes and sediment yields, the hydrological model SWAT (Soil and Water Assessment Tool) was applied. Before carrying out the modelling procedures, it was necessary to examine the level of SWC adoption among farmers and factors influencing the process so as to establish the baseline. To this end, biophysical and socio-economic factors assumed to affect farmers’ adoption tendency were examined using a household questionnaire. Modelling results indicate that if correctly implemented contour farming, fanya juu terracing and bench terracing would significantly reduce sediment yield at different rates. The reduction would range approximately between 1% - 85% with the highest percentage change achieved by practicing the three SWC methods simultaneously. However, such SWC measures would not increase water flow annually owing to evapotranspiration losses. Nevertheless, according to modelling results groundwater storage would be increased by about 14% and hence contributing to water supply during the dry season. The household questionnaire survey suggests that the adoption of SWC methods in the study area is very low and complex. While age of the head of household, access to extension (professional) services, household annual income and proximity to the farm significantly influenced farmers’ decision to adopt SWC, gender of the head of household, slope characteristics of the farm, number of adults in the household and farmer’s perception on soil erosion effects had no considerable influence on adoption. Therefore, to successfully realize the SWC benefits demonstrated by the modelling results, smallholder farmers upstream of the catchment should be incentivized to implement proper land management practices. Payment for ecosystem services scheme appears to be a suitable strategy. To make this operational, the Tanzanian government should establish a national water fund which will finance watershed management activities. The methodological approach employed in this thesis is transferrable to other sites with problems comparable to the studied catchment.
12

Impact of Land Management Practices on Water Balance and Sediment Transport in the Morogoro Catchment, Uluguru Mountains (Tanzania)

Kilemo, Dominico Benedicto 14 December 2017 (has links)
Tanzania, like other developing countries in the tropics is severely affected by the degradation of water resources owing to improper land management practices. Such practices affect water supply through soil erosion which does not only cause sedimentation of rivers and water bodies but also leads to a reduction in the rainwater infiltration capacity of soils. This thesis seeks to demonstrate how the implementation of proper land management measures can reduce soil erosion and increase water supply in the Morogoro River catchment (Uluguru Mountains). The proper practices referred to are the soil and water conservation (SWC) approaches which include contour farming, fanya juu terracing and bench terracing. The thesis combines social science and geoscience methods in a synergetic manner to address this research problem. To understand how and to what degree SWC methods affect water fluxes and sediment yields, the hydrological model SWAT (Soil and Water Assessment Tool) was applied. Before carrying out the modelling procedures, it was necessary to examine the level of SWC adoption among farmers and factors influencing the process so as to establish the baseline. To this end, biophysical and socio-economic factors assumed to affect farmers’ adoption tendency were examined using a household questionnaire. Modelling results indicate that if correctly implemented contour farming, fanya juu terracing and bench terracing would significantly reduce sediment yield at different rates. The reduction would range approximately between 1% - 85% with the highest percentage change achieved by practicing the three SWC methods simultaneously. However, such SWC measures would not increase water flow annually owing to evapotranspiration losses. Nevertheless, according to modelling results groundwater storage would be increased by about 14% and hence contributing to water supply during the dry season. The household questionnaire survey suggests that the adoption of SWC methods in the study area is very low and complex. While age of the head of household, access to extension (professional) services, household annual income and proximity to the farm significantly influenced farmers’ decision to adopt SWC, gender of the head of household, slope characteristics of the farm, number of adults in the household and farmer’s perception on soil erosion effects had no considerable influence on adoption. Therefore, to successfully realize the SWC benefits demonstrated by the modelling results, smallholder farmers upstream of the catchment should be incentivized to implement proper land management practices. Payment for ecosystem services scheme appears to be a suitable strategy. To make this operational, the Tanzanian government should establish a national water fund which will finance watershed management activities. The methodological approach employed in this thesis is transferrable to other sites with problems comparable to the studied catchment.
13

A study of current and possible future industrial engineering methodologies used to increase energy effieciency

Van der Merwe, Este 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Energy-related costs are increasing steadily. This is especially true in South Africa where we have been dealing with an energy crisis during the past couple of years. The increase in energy-related costs puts energy dependent industries under financial pressure. It is therefore imperative to find ways to improve the efficiency with which energy is being consumed in order to decrease the amount of money that has to be allocated to energy costs. The efficient consumption of energy at a facility is crucial and to increase that efficiency, Energy Management Programs (EMPs) should be implemented. An important component of EMPs is ascertaining the current energy consumption of a facility in order to identify areas where possible improvements can be made. This is done by completing an energy audit at the facility. After the energy audit has been completed and Energy Conservation Methods (ECMs) have been identified, the implementation of these methods should commence. The aim of this study is to determine how Industrial Engineering (IE) methods can play a more integral role in making South Africa more energy efficient. As part of this study, research was done to identify current EMCs being implemented in different areas and for different equipment in facilities. This information was compared to IE methods to identify the possible relationship between the ECMs and IE methods. Content analyses were completed on both IE and energy efficiency corpora using the Content Analysis Toolkit (CAT) program. These analyses identified important topics in these corpora and correlations between these topics in order to show correlations between the IE and energy efficiency fields. The most significant correlations identified, were between statistical methods and various energy efficiency topics. A case study was completed at a company in the Western Cape that manufactures electronic and integrated circuit products to implement the relevant ECMs. As part of the case study, an energy audit was completed at the facility. The implementation of a number of the ECMs has shown reductions in the daily kilowatt hours (kWh) consumptions. These reductions were obtained through the implementation of a Shut Down Management program, which highlights the importance of management in an energy conservation project. The application of optimisation algorithms for energy efficient design was examined through the optimisation of lighting design, using a Genetic Algorithm. It was found that a Genetic Algorithm is applicable to lighting design but requires further refinement in order to generate the most optimal design solutions. / AFRIKAANSE OPSOMMING: Kostes verbonde aan energieverbruik is voortdurend besig om toe te neem.Dit is veral relevant in Suid-Afrika waar ons tans ’n energiekrisis beleef. Hierdie toename in energieverwante kostes plaas energie-afhanklike industrieë onder groot finansiële druk. Dit is daarom belangrik om maniere te vind om energieverbruik meer effektief te maak sodat die bedrag geld wat aan energieverwante kostes toegestaan word, verminder kan word. Effektiewe energieverbruik by ’n fasiliteit is kritiek en om hierdie effektiwiteit te verbeter behoort ’n energiebestuursprogram by die fasiliteit geïmplimenteer te word. ’n Belangrike komponent van energiebestuursprogramme is die bepaling van die huidige energieverbruik en dit word gebruik om die areas te identifiseer waar moontlike verbeteringe aangebring kan word. Die energieverbruik word bepaal deur ’n energie-oudit. Nadat die energie-oudit voltooi en die energiebesparingsmetodes bepaal is, moet hierdie metodes by die fasiliteit geïmplementeer word. Hierdie studie probeer vasstel hoe bedryfsingenieurswesemetodes ‘n groter rol kan speel in die proses om Suid-Afrika meer energie-effektief te maak. Navorsing is gedoen oor energiebesparingsmetodes wat in verskillende areas en vir verskillende toerusting in fasiliteite geïmplementeer word. Hierdie inligting is daarna vergelyk met bedryfsingenieurswesemetodes om juis die moontlike verhouding tussen hierdie twee tipe metodes te identifiseer. Analises was gedoen in bedryfsingenieurswese en energie-effektiwiteitskorpusse met die gebruik van die ‘Content Analysis Toolkit’ program. Belangrike onderwerpe en verwantskappe tussen hierdie onderwerpe in die korpusse is identifiseer om sodoende korrelasies tussen die bedryfsingenieurswese- en energie-effektiwiteitsveld uit te lig. Die mees betekenisvolle korrelasies was tussen statistiese metodes en verskeie energieeffektiwiteitsonderwerpe identifiseer. ’n Gevallestudie is by ’n maatskappy in die Wes-Kaap wat geïntegreerde elektroniese stroombane vervaardig gedoen, om die relevante energiebesparingsmetodes te implementeer. ’n Energie-oudit is as deel van die gevallestudie by die fasiliteit gedoen. Die aantal energiebesparingsmetodes wat wel geïmplementeer is, het ’n verlaging in die kilowatture (kWh) teweeggebring. Hierdie verlagings is verkry deur die implementering van ’n afskakelingsbestuursprogram wat die belangrikheid van bestuur in ’n energiebesparingsprogram uitlig. Die toepaslikheid van optimiseringsalgoritmes vir energie-effektiewe ontwerp is getoets deur die optimisering van ’n liguitlegontwerp met behulp van ’n genetiese algoritme. Daar is gevind dat ’n genetiese algoritme wel toegepas kan word, maar dat dit verbeteringe benodig.
14

Atividade da polifenoloxidase em camarão(Litopenaeus vannamei) submetido ao emprego do frio e atmosfera modificada. / Polyphenoloxidase activity shrimp (Litopenaeus vannamei) submitted to the use of modified atmosphere cold.

Oliveira, Lucivânia Assis de 26 February 2013 (has links)
Made available in DSpace on 2015-04-17T14:49:23Z (GMT). No. of bitstreams: 1 ArquivoTotal.pdf: 1254323 bytes, checksum: 6acc00404bdf28b53693a7553204b077 (MD5) Previous issue date: 2013-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / After despesca shrimp is highly perishable, with a shelf life limited due to the occurrence of melanosis and microbial contamination. The melanosis is triggered by a biochemical mechanism that oxidizes phenols to quinones by the enzyme polyphenol oxidase (PPO). Quinones in turn react non-enzymatically with other compounds forming dark melanin pigments responsible for melanosis. Although not damaging to consumer health, melanosis dramatically reduces the commercial value of the shrimp. The aim of this study was to evaluate the enzymatic activity of PPO shrimp Litopenaeus vannamei subjected to freezing, modified atmosphere and cooling in ice for their respective stores. Samples were obtained in trading environment, packed and transported to the Laboratory of Technology and Processing Meat and Fish (LTPCP / DEA / UFPB). The products were made from whole shrimp and subsequently submitted to the following treatments: the domestic freezer (-18 ± 1 ° C) - FREEZER; tunnel freezing at (-35 ° C) - TUNNEL, liquid nitrogen (-86 ° C) - NITROGEN; cooling on ice - ICE; Modified Atmosphere (75% CO2 / 25% O2) - AM1, Modified Atmosphere (25% CO2 / 75% O2) - AM2 and Vacuum Packaging - VOID. The samples were stored subjected to freezing (-18 ° C) for 90 days, and the samples cooled on ice and modified atmosphere were stored for 9 days. The vacuum packaging liquid nitrogen and were more effective in inhibiting PPO activity, and delayed melanosis during storage. The color parameters pH, shear force and water activity have changed over time, both in frozen samples as in chilled. / Após a despesca o camarão é muito perecível, com vida de prateleira limitada, devido à melanose e contaminação microbiológica. A melanose é desencadeada por um mecanismo bioquímico que oxida fenóis a quinonas pela enzima polifenoloxidase (PPO). As quinonas por sua vez, reagem não enzimáticamente com outros compostos formando melaninas pigmentos escuros, responsável pela melanose. Apesar de não causar danos à saúde do consumidor, a melanose reduz drasticamente o valor comercial do camarão. O objetivo deste trabalho foi avaliar a atividade enzimática da PPO do camarão Litopenaeus vannamei submetido ao congelamento, atmosfera modificada e ao resfriamento em gelo durante seus respectivos armazenamentos. As amostras foram obtidas em ambiente de comercialização, acondicionadas e transportadas ao Laboratório de Tecnologia e Processamento de Carnes e Pescado (LTPCP/DEA/UFPB). Os produtos foram elaborados a partir de camarões inteiros e posteriormente, submetidos aos seguintes tratamentos: freezer doméstico à (-18 ± 1 °C) FREEZER; túnel de congelamento a (-35 °C) TÚNEL; nitrogênio líquido (-86 °C) NITROGÊNIO; refrigeração em gelo GELO; Atmosfera Modificada (75%CO2 / 25% O2) AM1; Atmosfera Modificada (25%CO2 /75% O2) AM2 e Embalagem a Vácuo VÁCUO. As amostras congeladas foram armazenadas (-18 °C) por 90 dias e as amostras refrigeradas em gelo e atmosfera modificada foram armazenadas durante 9 dias. O nitrogênio líquido e a embalagem a vácuo mostraram-se mais eficácia na inibição da atividade da PPO e no retardamento da melanose durante o período de armazenamento. Quanto aos parâmetros físicos houve uma redução na cor e atividade água e um aumento no pH e força de cisalhamento ao longo do tempo, tanto nas amostras congeladas como nas refrigeradas.
15

The skeletal remains of the naval ship Mars : An osteological pre-study for analysing digitally documented skeletalremains in a marine context

Fredriksson, Matilda January 2015 (has links)
Denna kandidatuppsats är ämnad att ligga som grund för framtida osteologisk dokumentation ochanalys av de skeletala kvarlevorna från skeppet Mars, och är utförd i samarbete med projektet SkeppetMars (1564).Syftet med denna uppsats är att undersöka och problematisera möjligheterna att analyseradigitalt dokumenterade skeletala kvarlevor i en marin miljö. För att utvärdera möjligheterna ochbegränsningarna med att utföra en digital osteologisk analys utfördes en mindre studie av det digitaltdokumenterade material som hittills insamlats från skeppet Mars. Analysen visade att en osteologiskanalys kan utföras på digitalt dokumenterade skeletala kvarlevor men att det finns begränsningar medatt utföra en analys av ett två dimensionellt källmaterial. Syftet med denna uppsats är även attdiskutera och lyfta fram hur skeletala kvarlevor påverkas under längre tid i marina sediment* samtbräckt/salt vatten. Syftet med denna uppsats är även att diskutera hur en hypotetisk inhämtning och konservering av de skeletala kvarlevorna från skeppet Mars bör utföras. / This bachelor's thesis is intended to lay the ground for future osteological documentation and analysisof the skeletal remains from the naval ship Mars, and is conducted with the project Skeppet Mars(1564). The main purpose of this thesis is to examine and problematise the possibility to analysedigitally documented skeletal remains in a marine context. In order to evaluate the possibilities andlimitations of performing an osteological analysis, a small analysis was conducted on the digitallydocumented skeletal remains collected from the naval ship Mars so far. The analysis showed that anosteological analysis can be performed on digitally documented skeletal remains, there are, however,limitations of performing an analysis on a two dimensional documentation. The secondary purpose ofthis thesis is to discuss and highlight how skeletal remains are affected by marine sediment* andbrackish/saltwater over a long period of time. An additional goal for this thesis is to discuss how ahypothetical retrieval and conservation of the skeletal remains of the naval ship Mars shouldpreferably be performed.

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