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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.
1

Influence of partial rootzone drying on aspects of grape and wine quality.

Bindon, Keren A. January 2004 (has links)
Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The effect of partial rootzone drying (PRD) on the composition of grape and wine secondary metabolites was investigated. At harvest, total anthocyanin and phenolic concentration in fruit of Vitis vinifera L. cvs Shiraz and Cabernet Sauvignon was either unaltered or increased in response to PRD over two seasons. Where an increase in anthocyanin concentration was found with PRD, this was found to be independent of berry size. Rather, increases in anthocyanin concentration were most likely due to an increase in anthocyanin production in the berry skins. In Cabemet Sauvignon wine made from one vintage, total colour was enhanced by 10% in response to the PRD treatment, although in that season total anthocyanin concentration was unaltered in the fruit or wine. This colour enhancement was due to an increase in coloured pigments in copigmented or polymeric form, that is in association with other anthocyanins or phenolic compounds. This is a significant finding, as it shows that the colour of wine is not dependent upon anthocyanin concentration alone, but rather on reactions taking place during winemaking and wine-ageing. The colour enhancement was found to be maintained after a year's ageing in the bottle. A key question which arises from this work is which component(s) of total phenolics in PRD-treated wines is responsible for this effect. Preliminary investigation of seed proanthocyanidins and flavan-3-ols showed that their content per berry was unaltered by the PRD treatment. However, where berry weight was decreased due to PRD, the concentration of these seed tannins was increased on a per gram basis. This could potentially lead to an increased contribution of seed tannins to total wine phenolics in PRD wines. The effect of this is two-fold. Firstly, seed tannins are known to be weak copigments and could in part account for the increased copigmentation and polymerisation of anthocyanins observed with PRD. Secondly, an increased concentration of seed tannins in PRD wines could alter wine astringency and mouth feel properties. In both fruit and wine samples, PRD was found to cause a decrease in the contribution malvidin-glucosides to total anthocyanins. Thus, levels of non-malvidin glucosides, namely delphinidin and cyanidin, were increased by PRD. This effect was investigated as fruit matured post-veraison, and was evident from early in berry development. Preliminary results indicate that this response requires the presence of high incident light levels to the fruit during development, but is not mediated by increased bunch exposure alone. Shading of fruit led to a significant decrease in all anthocyanin types, and caused a shift in the ratio of acetyl- and 3p-coumary1-glucosides to mono-glucosides. The PRD treatment, however, did not cause changes in the proportions of acetyl-, 3p-coumary1-and mono-glucoside anthocyanins. These results show that the response of the anthocyanin pathway to the PRD treatment is most likely mediated by physiological signals within the fruit and vine, rather than due to a change in bunch zone microclimate. An important class of potential flavour and aroma compounds in grapes are the C₁₃-norisoprcnoids. As the precursors to these compounds are fruit-derived, rather than by-products of fermentation, the potential exists for their manipulation using viticultural practices. Previously, bunch exposure has been thought to be the primary factor mediating the final levels of C₁₃-norisoprenoids in fruit. The current study has shown that total shading of developing bunches using artificial means led to a significant decrease in the levels of these compounds in both fruit and wine samples of Shiraz. However, when fruit of this variety was subjected to natural changes in bunch exposure, resulting from alterations in canopy structure, the response of the C₁₃-norisoprenoids to these conditions was either small or insignificant. Of the three C₁₃-norisoprenoids studied, namely ß -damascenone, ß -ionone and TDN, only TDN showed a significant response to bunch exposure under these conditions. Preliminary results of this study on Shiraz indicated that the concentration of the C₁₃-norisoprenoids ß -damascenone and TDN can potentially be influenced by changes in vine shoot vigour and canopy architecture, induced by a water-deficit. This finding was validated by a study on Cabernet Sauvignon, where the effect of PRD on fruit C₁₃-norisoprenoids was investigated. The concentrations of the C₁₃-norisoprenoids ß -damascenone, ß -ionone and TDN were shown to be increased by up to 30% in response to PRD in Cabernet Sauvignon fruit over two vintages. The changes in these compounds in the fruit were associated with increased levels of the carotenoids lutein and ß -carotene, which are potential precursors to the C₁₃-norisoprenoids. The results of the current study have shown that the regulation of C₁₃- norisoprenoid concentration in grapes and wine may not be primarily due to the level of incident light on developing bunches, although the presence of light is necessary for their production. Rather, the effect of deficit irrigation practices on whole-vine physiology and vine shoot vigour holds stronger potential as a tool for the viticultural manipulation of these compounds in fruit and wine. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1129092 / Thesis (Ph.D.) -- University of Adelaide, School of Wine and Agriculture, 2004
2

Influence of partial rootzone drying on aspects of grape and wine quality.

Bindon, Keren A. January 2004 (has links)
Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The effect of partial rootzone drying (PRD) on the composition of grape and wine secondary metabolites was investigated. At harvest, total anthocyanin and phenolic concentration in fruit of Vitis vinifera L. cvs Shiraz and Cabernet Sauvignon was either unaltered or increased in response to PRD over two seasons. Where an increase in anthocyanin concentration was found with PRD, this was found to be independent of berry size. Rather, increases in anthocyanin concentration were most likely due to an increase in anthocyanin production in the berry skins. In Cabemet Sauvignon wine made from one vintage, total colour was enhanced by 10% in response to the PRD treatment, although in that season total anthocyanin concentration was unaltered in the fruit or wine. This colour enhancement was due to an increase in coloured pigments in copigmented or polymeric form, that is in association with other anthocyanins or phenolic compounds. This is a significant finding, as it shows that the colour of wine is not dependent upon anthocyanin concentration alone, but rather on reactions taking place during winemaking and wine-ageing. The colour enhancement was found to be maintained after a year's ageing in the bottle. A key question which arises from this work is which component(s) of total phenolics in PRD-treated wines is responsible for this effect. Preliminary investigation of seed proanthocyanidins and flavan-3-ols showed that their content per berry was unaltered by the PRD treatment. However, where berry weight was decreased due to PRD, the concentration of these seed tannins was increased on a per gram basis. This could potentially lead to an increased contribution of seed tannins to total wine phenolics in PRD wines. The effect of this is two-fold. Firstly, seed tannins are known to be weak copigments and could in part account for the increased copigmentation and polymerisation of anthocyanins observed with PRD. Secondly, an increased concentration of seed tannins in PRD wines could alter wine astringency and mouth feel properties. In both fruit and wine samples, PRD was found to cause a decrease in the contribution malvidin-glucosides to total anthocyanins. Thus, levels of non-malvidin glucosides, namely delphinidin and cyanidin, were increased by PRD. This effect was investigated as fruit matured post-veraison, and was evident from early in berry development. Preliminary results indicate that this response requires the presence of high incident light levels to the fruit during development, but is not mediated by increased bunch exposure alone. Shading of fruit led to a significant decrease in all anthocyanin types, and caused a shift in the ratio of acetyl- and 3p-coumary1-glucosides to mono-glucosides. The PRD treatment, however, did not cause changes in the proportions of acetyl-, 3p-coumary1-and mono-glucoside anthocyanins. These results show that the response of the anthocyanin pathway to the PRD treatment is most likely mediated by physiological signals within the fruit and vine, rather than due to a change in bunch zone microclimate. An important class of potential flavour and aroma compounds in grapes are the C₁₃-norisoprcnoids. As the precursors to these compounds are fruit-derived, rather than by-products of fermentation, the potential exists for their manipulation using viticultural practices. Previously, bunch exposure has been thought to be the primary factor mediating the final levels of C₁₃-norisoprenoids in fruit. The current study has shown that total shading of developing bunches using artificial means led to a significant decrease in the levels of these compounds in both fruit and wine samples of Shiraz. However, when fruit of this variety was subjected to natural changes in bunch exposure, resulting from alterations in canopy structure, the response of the C₁₃-norisoprenoids to these conditions was either small or insignificant. Of the three C₁₃-norisoprenoids studied, namely ß -damascenone, ß -ionone and TDN, only TDN showed a significant response to bunch exposure under these conditions. Preliminary results of this study on Shiraz indicated that the concentration of the C₁₃-norisoprenoids ß -damascenone and TDN can potentially be influenced by changes in vine shoot vigour and canopy architecture, induced by a water-deficit. This finding was validated by a study on Cabernet Sauvignon, where the effect of PRD on fruit C₁₃-norisoprenoids was investigated. The concentrations of the C₁₃-norisoprenoids ß -damascenone, ß -ionone and TDN were shown to be increased by up to 30% in response to PRD in Cabernet Sauvignon fruit over two vintages. The changes in these compounds in the fruit were associated with increased levels of the carotenoids lutein and ß -carotene, which are potential precursors to the C₁₃-norisoprenoids. The results of the current study have shown that the regulation of C₁₃- norisoprenoid concentration in grapes and wine may not be primarily due to the level of incident light on developing bunches, although the presence of light is necessary for their production. Rather, the effect of deficit irrigation practices on whole-vine physiology and vine shoot vigour holds stronger potential as a tool for the viticultural manipulation of these compounds in fruit and wine. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1129092 / Thesis (Ph.D.) -- University of Adelaide, School of Wine and Agriculture, 2004
3

Development, testing and application of a crop nitrogen and phosphorus model to investigate leaching losses at the local scale

Van der Laan, Michael 04 June 2010 (has links)
The leaching of nitrogen (N) and phosphorus (P) from the rootzone of cropping systems is a major contributor of non-point source pollution resulting in deterioration of fresh water supplies. An escalating world population is forcing further intensification of agricultural production practices and the identification of suitable and effective management practices to reduce N and P leaching losses is becoming ever more important. Such leaching losses are, however, extremely challenging to measure and quantify due to uncertainties associated with the estimation of deep drainage and N and P concentrations in this drainage water. SWB-Sci is a locally developed, mechanistic crop model to which N and P subroutines have been added to enable analysis of leaching losses at the local scale. This involved novel approaches to estimate the effects of N deficiencies on yield; to simulate crop P demand, uptake and stress effects; to simulate banded P fertilizer applications; and to estimate incomplete solute mixing. New equations to estimate the size of the Labile P pool from soil P tests commonly used in South Africa, and guidelines on the classification of South African soils as calcareous, slightly weathered or highly weathered which is required to simulate P, were also developed. The upgraded more versatile model was tested using historical datasets from the Netherlands, Kenya and South Africa, and performed well in simulating N and P dynamics in maize and wheat cropping systems. Variables tested included aboveground dry matter production, yield, leaf area index, aboveground crop N and P mass, grain N and P mass, soil water content ABSTRACT xvii and soil inorganic N levels. A study was also conducted on a large drainage lysimeter into which suction cups and wetting front detectors were installed, and data from this experiment together with the SWB-Sci model was used to study vertical solute movement more closely. As hypothesized, wetting front detector nitrate (NO3-) and P concentrations were observed to align closely with simulated mobile phase concentrations, and suction cup NO3- concentrations were observed to align closely with simulated immobile phase concentrations. These results confirm that monitoring and modelling can be used together to improve understanding and obtain more accurate estimates of N and P leaching losses, and further work on this approach is recommended for a wide range of soils and cropping systems. Finally, long-term modelling with the SWB-Sci model was used to analyse and compare N and P leaching losses from a dryland versus an irrigated monoculture maize production system. Over a 30 year simulation period, irrigated maize was estimated to leach considerably higher loads of N and P (~ 4-fold higher). For dryland production, zero leaching was observed for consecutive years on several occasions, with major leaching losses associated with high rainfall events. A ‘room for rain’ irrigation scheduling management practice was estimated to reduce N leaching by 12% and P leaching by 14%, while a crop rotation system which incorporated wheat grown over the winter months was estimated to reduce N leaching by 23% and P leaching by 24%. From this study, long-term modelling was confirmed as an effective approach to investigate N and P leaching losses, to assist with the planning and design of field trials, and to assess the effectiveness of best management practices. It is envisaged that SWB-Sci will continue to evolve as a valuable tool for analysing and reducing N and P leaching losses from cropping systems to further reduce non-point source pollution. / Thesis (PhD)--University of Pretoria, 2010. / Plant Production and Soil Science / unrestricted
4

Desempenho de um sistema de alagado construído, plantado com capim vetiver (chrysopogon zizanioides (l.) roberty), na remoção de metais e de p, s e se de resíduos de fossa / Performance of a constructed wetland system planted with Vetiver grass (Chrysopogon zizanioides (L.) Roberty) in removing metals and P, S and Se from cesspools residues

Cardoso Filho, Delcir Magalhães 17 June 2015 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-27T14:26:57Z No. of bitstreams: 2 Dissertação - Delcir Magalhães Cardoso Filho - 2015.pdf: 1361711 bytes, checksum: efc64fdbb620dc4c287b17ce56d2aaed (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-27T14:28:50Z (GMT) No. of bitstreams: 2 Dissertação - Delcir Magalhães Cardoso Filho - 2015.pdf: 1361711 bytes, checksum: efc64fdbb620dc4c287b17ce56d2aaed (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-27T14:28:50Z (GMT). No. of bitstreams: 2 Dissertação - Delcir Magalhães Cardoso Filho - 2015.pdf: 1361711 bytes, checksum: efc64fdbb620dc4c287b17ce56d2aaed (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-06-17 / The pits and septic tanks wastes have high organic load, pathogens, metals and other elements, requiring appropriate treatment for not pollute the environment. Among the alternatives for their treatment, it has recently been proposed to use constructed wetlands. However, information on such use is scarce. Therefore, this study aimed to evaluate the performance of a constructed wetlands system using the Vetiver grass plant species (Chrysopogon zizanioides), on removing metals, P, S and Se from cesspools residues. Two tanks were constructed, dug into the ground (planted tank and control) and filled with a substrate consisting of gravel # 0, gravel # 1 and medium sand. The system built has operated under batch, with Hydraulic Retention Time of six days and subsurface vertical downward flow. Through obtained concentrations of different inorganic elements on: the applied cesspools residues; the treated effluent; the sludge accumulated at tanks surface and; the vegetal tissues, they were calculated: the total loads influent to the system; the output loads; the efficiency in removing attributes; the load accumulated at tanks surface; the load absorbed by macrophytes and; the loads retained in the roots and by the substrate. The attributes removal efficiency was calculated considering the evapotranspiration that showed an average rate of 40.27% in the Vetiver tank. The applied cesspools residues showed considerable variability in their concentrations. The concentrations of the treated effluent were subjected to Tukey test (α = 0.05). The effluents concentrations from Vetiver and control tanks statistically differed only for antimony, sulfur and iron, but the Vetiver grass showed removal efficiency greater than 20% to 30 of the 33 analyzed parameters. / Os resíduos de fossas e tanques sépticos possuem elevada carga orgânica, microrganismos patogênicos, metais e outros elementos, necessitando de tratamento adequado para não poluir o ambiente. Dentre as alternativas para seu tratamento, recentemente tem sido proposta a utilização de alagados construídos. Todavia, as informações sobre tal uso são ainda escassas. Assim, este trabalho teve como objetivo avaliar o desempenho de um sistema de alagado construído, utilizando a espécie vegetal capim Vetiver (Chrysopogon zizanioides), na remoção de metais, P, S e Se do resíduo de fossa. Foram escavados dois tanques idênticos (tanque plantado e controle) sendo preenchidos com meio suporte formado por brita # 0, brita # 1 e areia média. O sistema construído operou em regime de batelada, com Tempo de Detenção Hidráulica de seis dias e fluxo subsuperficial vertical descendente. Por meio das concentrações obtidas para diferentes elementos inorgânicos: no resíduo de fossa aplicado; no efluente tratado; no lodo superficial acumulado e; nos tecidos das macrófitas, foram calculadas: as cargas totais afluentes do sistema; as cargas de saída; a eficiência na remoção inorgânica; as cargas acumuladas no lodo superficial; as cargas absorvidas pelas macrófitas e; as cargas retidas nas raízes e no meio suporte. A eficiência na remoção inorgânica foi calculada considerando a evapotranspiração, que apresentou taxa média de 40,27% no tanque Vetiver. Os resíduos de fossa aplicados apresentaram grande variabilidade em suas concentrações. As concentrações do efluente tratado foram submetidas ao teste de Tukey (α = 0,05). As concentrações de saída dos tanques Vetiver e Controle diferiram estatisticamente apenas para Antimônio, Enxofre e Ferro, contudo o capim Vetiver apresentou eficiência de remoção superior a 20% para 30 dos 33 atributos analisados. Palavras-chave: capim Vetiver, remoção de metais, zona de raízes.
5

Alagados construídos para tratamento de águas cinzas com meio suporte de resíduos de construção e demolição

Venske, Felipe 01 June 2017 (has links)
Submitted by Eunice Novais (enovais@uepg.br) on 2017-09-19T19:17:55Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Felipe Venske.pdf: 1396319 bytes, checksum: 2da5f58e6b609035c63d0cdf8246fa5a (MD5) / Made available in DSpace on 2017-09-19T19:17:55Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Felipe Venske.pdf: 1396319 bytes, checksum: 2da5f58e6b609035c63d0cdf8246fa5a (MD5) Previous issue date: 2017-06-01 / O aumento da população, excesso de uso e a má gestão dos recursos naturais colaboram para a escassez de água potável e o aumento dos resíduos sólidos nos centros ubanos. Este problema é amenizado com a reutilização da água cinza e dos resíduos da construção e demolição. Neste trabalho, um sistema de alagados construídos foi considerado como alternativa para reuso de águas servidas e utilização de resíduos, devido a baixa manutenção, operação simplificada, utilização dos resíduos sólidos, e com tratamento de qualidade. Desta forma, o trabalho objetivou estudar a viabilidade técnica da utilização de um sistema de alagados construídos com meio suporte de resíduos da construção e demolição para tratamento de água cinza sintética em escala piloto de fluxo horizontal subsuperficial com a utilização da planta ornamental Copo-de-Leite (Zantedeschia aethiopica). O experimento teve dois estudos principais (sistema estático e sistema dinâmico) com alteração do tempo de detenção hidráulica, de dois, quatro e seis dias para o estático e de um e dois dias para o sistema dinâmico. Os resultados indicaram que o alagado construído obteve para o sistema estático uma redução de 86% para a DQO e de 20% para Fósforo Total. Verificou-se um aumento de 117% para Sólidos Totais, 112% para Condutividade elétrica e pH máximo de 9,6. Já para o sistema dinâmico houve redução de 86% para a DQO, 8% para Fósforo Total, e aumento de 1100% de Sólidos Totais, 327% de Condutividade e pH máximo de 7,7. A planta ornamental adaptou-se bem ao experimento, com uma grande densidade de raízes, que englobaram todo o sistema, provando a sua eficácia na remoção de matéria orgânica, além do enriquecimento estético e o aumento de aceitação do público. Assim, conclui-se que o SAC estudado é um sistema viável para a reutilização de água cinza para fins não potáveis, porém a utilização do resíduo de construção e demolição como meio suporte não é o mais adequado, devido a interferências no efluente, sendo preferível encontrar outra destinação para este material. / The increase in population and the mismanagement of natural resources cause the scarcity of drinkable water and increase in solid waste in urban areas. These problems can be mitigated with the reutilization of greywater and construction and demolition waste. In this work, the constructed wetlands was considered as an alternative for solid waste use ad wastewater reutilization, due to its quality of treatment, low maintenance, simplified operation and employment of solid waste. Thus, this work aimed to assess the technical feasibility of a pilot-scale horizontal subsurface flow constructed wetlands system with solid waste as substrate for the treatment of synthetic greywater using the ornamental plant Zantedeschia Aethiopica. The experiment presented two main studys (static system and dynamic system) with the alteration of the hydraulic retention time – two, four and six days for the static system; one and two days for the dynamic system. Results showed that the constructed wetlands obtained, for the static system, a reduction of 86% in COD and 20% in total phosphorus, but an increase of 117% in total solids and 112% in conductivity as well as a maximum pH of 9.6. For the dynamic system, there was a reduction of 86% in COD and 8% in total phosphorus, and an increase of 1100% in total solids and 327% in conductivity as well as a maximum pH of 7.7. The ornamental plant resisted well to the experiment. It presented a high density of roots, which involved the whole system, what shows its efficiency in the removal of organic matter besides esthetically enhancing the system and increasing the public’s acceptance. Therefore, it can be concluded that the constructed wetlands studied is feasible for the reutilization of greywater for non-drinkable purposes, however, the use of construction and demolition waste as support medium is not the most suitable due to the interferences on wastewater. It is recommended to find another destination for this material.
6

Development of a turf stability assessment method for sports surfaces

Anderson, Frazer D. January 2018 (has links)
The majority of outdoor sports are played on natural turf pitches. Throughout the playing season, a pitch has continual player interaction, which, during periods of sustained unfavourable conditions, can cause the turf to tear up (shear) under player contact. This is most evident in Rugby Union scrummages, which create deep divots in the turf and rootzone that reduce player safety and are criticised by the media. However, little is known of the turf/rootzone strength to depth, termed 'shear stability' in this thesis, and there is currently no appropriate means to test this property. In order to explore the shear stability of turf, a device was designed and developed. The prototype device, termed the 'Shear Tester', underwent trial, validation and several redesigns until it was deemed suitable to investigate turf shear stability. A range of natural and hybrid constructions and laboratory-controlled samples were investigated, and the key variables found to influence the shear stability were grass rooting, water content and rootzone density.

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