• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 88
  • 13
  • 7
  • 4
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 151
  • 39
  • 23
  • 17
  • 16
  • 15
  • 12
  • 11
  • 11
  • 11
  • 10
  • 8
  • 8
  • 8
  • 7
  • 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.
141

The management of potable water supply in Mogwase Township, Moses Kotane Local Municipality / Daniel Kagiso Mosime

Mosime, Daniel Kagiso January 2014 (has links)
The continuous population growth and the notable development of the mining industry have resulted in challenges for potable water supply in South Africa. The ever-increasing number of people migrating to urban areas has resulted in the demand of potable water supply in South Africa. Water is regarded as a human basic right which is promulgated by the recent amendment of the potable water service provisioning Water Services Act 108 of 1997 and the National Water Act 36 of 1998. The afore-mentioned Acts started a process to address the imbalance that existed during the apartheid regime. (The apartheid regime essentially had one objective initially, namely the control of (black, coloured and Indian) people in order to protect white privilege). It was meant to separate people of different races).The Acts were formulated to address the equal distribution of national resource for all South Africans. Mogwase Township in Moses Kotane Local Municipality is undergoing continuous growth with several mining areas being developed. Consequently, the supply of potable water has been a challenge in the area. It is, therefore, in the interest of the researcher to investigate the management of potable water supply in Mogwase Township with the aim of suggesting improved service delivery by the Moses Kotane Local Municipality. Water is now recognised as a scarce resource that belongs to all South Africans. The provision of potable water by the water services authorities (WSAs) is an important basic service that faces a number of challenges, such as the use of outdated infrastructure, namely: pipelines from the Vaalkop Dam, the lack of skilled and knowledgeable people, improper planning, and the booming population that place overt pressure on the demand for effective and efficient service delivery. This research was undertaken to investigate how Moses Kotane Local Municipality which obtains its potable water supply from Vaalkop Dam can improve the supply of water in a more effective, efficient, equitable, economic and sustainable manner through improved co-operative governance and integrated water resource management (IWRM). The qualitative and quantitative research designs were used to conduct the research, which included a literature review, semi-structured interviews, data sampling and scientific analysis of the responses. The researcher arrived at logical conclusions and S.M.A.R.T. (Simple, Measureable, and Achievable Realistic Timebound) recommendations with regard to all aspects related to the future management of potable water supply in Mogwase Township. / MA (Development and Management), North-West University, Potchefstroom Campus, 2015
142

The requirements for the development of a spatial information system for the Tlokwe Local Municipality water catchments area / Sydney Peter Riekert

Riekert January 2014 (has links)
The problem facing the Tlokwe Local Municipality is that it is Constitutional and legislatively obliged to avoid and/or mitigate the impact of potential disasters within its boundaries, through the effective management of potential disaster risks and disasters. The lack of effective risk management tools is especially concerning in the context of the water catchment management of the Mooi River, which is the main water supply of the Tlokwe local Municipality. The Mooi River is exposed to many potential catchment related hazards that could affect the municipality of which the origins are both anthropogenic and natural. Although, many of the impacts on the catchment arise beyond the boundaries and the control of the municipality, this does not relieve the municipality from the responsibility to develop tools to manage the risks. The aim of the study is to assist in addressing the above stated problem through establishing the requirements for a conceptual model for an effective spatial information system that will assist the municipality in effectively managing the potential disaster risks and disasters that may arise in the Mooi River Catchment area that could impact on the Tlokwe Local Municiaplity. The aim gives rise to three-research questions that are formulated as research objectives that are used to identify the conceptual model requirements. The first is to identify and conceptualise the constitutional and legislative obligations in respect of disaster risk management in general and specifically those governing the disaster disk management in the water catchment area for the Mooi River. The study of this objective not only highlight the constitutional and legal obligations that the local municipality is subject to, but provides legislatives remedies that the local municipality can utilise to assist with disaster risks reduction. The second is to identify and conceptualise the generic hazards that are related to water catchment areas (including the related groundwater compartments) and those specific in the Mooi River catchment area. In this section, potential anthropogenic and natural hazards are listed, a methodology for risk and vulnerability analyses is provided, and a concise study of quaternary catchment C23D is provided. The third is to identify and conceptualize the requirements for an effective conceptual model of GIS for Disaster Risk Management in the Tlokwe Local Municipality. An overview of a GIS is provided. The essential components of a generic information system namely, people, software, hardware, procedures and processes, data and telecommunications or networks are discussed. The information and system requirements cumulating from the analyses of the three research questions, serve as the drivers of the goal, outcomes and transformation process of the system as well as the requirements for the conceptual model. In this section: a comparison of the Systems Development Life Cycle (SDLC), Framework for Applied Systems Thinking (FAST), problem solving and the phases addressed in this study; the identification of the conceptual model requirements; and a concise systems conceptualisation of an effective GIS is provided. As the, mini-dissertation focuses on the needs for a conceptual model, the additional activities required before the system can be implemented are identified and formulated as recommendation that provide the opportunity for future research. / M Development and Management, North-West University, Potchefstroom Campus, 2014
143

The management of potable water supply in Mogwase Township, Moses Kotane Local Municipality / Daniel Kagiso Mosime

Mosime, Daniel Kagiso January 2014 (has links)
The continuous population growth and the notable development of the mining industry have resulted in challenges for potable water supply in South Africa. The ever-increasing number of people migrating to urban areas has resulted in the demand of potable water supply in South Africa. Water is regarded as a human basic right which is promulgated by the recent amendment of the potable water service provisioning Water Services Act 108 of 1997 and the National Water Act 36 of 1998. The afore-mentioned Acts started a process to address the imbalance that existed during the apartheid regime. (The apartheid regime essentially had one objective initially, namely the control of (black, coloured and Indian) people in order to protect white privilege). It was meant to separate people of different races).The Acts were formulated to address the equal distribution of national resource for all South Africans. Mogwase Township in Moses Kotane Local Municipality is undergoing continuous growth with several mining areas being developed. Consequently, the supply of potable water has been a challenge in the area. It is, therefore, in the interest of the researcher to investigate the management of potable water supply in Mogwase Township with the aim of suggesting improved service delivery by the Moses Kotane Local Municipality. Water is now recognised as a scarce resource that belongs to all South Africans. The provision of potable water by the water services authorities (WSAs) is an important basic service that faces a number of challenges, such as the use of outdated infrastructure, namely: pipelines from the Vaalkop Dam, the lack of skilled and knowledgeable people, improper planning, and the booming population that place overt pressure on the demand for effective and efficient service delivery. This research was undertaken to investigate how Moses Kotane Local Municipality which obtains its potable water supply from Vaalkop Dam can improve the supply of water in a more effective, efficient, equitable, economic and sustainable manner through improved co-operative governance and integrated water resource management (IWRM). The qualitative and quantitative research designs were used to conduct the research, which included a literature review, semi-structured interviews, data sampling and scientific analysis of the responses. The researcher arrived at logical conclusions and S.M.A.R.T. (Simple, Measureable, and Achievable Realistic Timebound) recommendations with regard to all aspects related to the future management of potable water supply in Mogwase Township. / MA (Development and Management), North-West University, Potchefstroom Campus, 2015
144

The management of potable water supply in Khuma Township, Matlosana Local Municipality / Kagisho Simon Monnahela

Monnahela, Kagisho Simon January 2014 (has links)
The birth of a non-racial democracy in South Africa brought many challenges such as the supply of potable water to all societies irrespective of their colour or even location. Migration of people from rural to urban has increased the demand of potable water supply in many areas that were previously neglected by the former Apartheid regime. The increase of the human population in urban or developing areas of South Africa will therefore imply that various public services such as potable water supply, proper housing, electricity supply, schooling and basic health facilities should be provided in an efficient, effective and economic manner. As the resident of Khuma Township, the researcher has a keen interest in the management of potable water supply in this area, inter alia, the nature and extent of the physical environment and the efficiency and effectiveness of a potable water supply as a means of improving service delivery by the Matlosana Local Municipality to Khuma Township. The area has the history of gold mining and the majority of the people from other rural areas and neighbouring states moved into this area and were later joined by their families. This resulted in an increase in the population to a point where people were placed in dangerous areas such as underlying dolomite and along the Koekemoer spruit. For example, extension 6 is known to experience sinkholes due to underground mining activities and the underline dolomite rock. The population has increased in Khuma Township to such an extent that a shortage of potable water supply is been experienced. Khuma Township had one water reservoir for the past 40 years and Matlosana Local Municipality did not improve or developed infrastructure related to potable water supply to be able to cater for the increasing population of this area. An empirical study was conducted in among the residents of Khuma Township, Matlosana Local Municipality and role-players in the management of potable water supply. From this study, it was evident that the supply of potable water in Khuma Township is insufficient, and there was poor communication, cooperation and participation between Matlosana Local Municipality and the residents of Khuma Township. The ineffective management of potable water supply in Khuma Township by the Matlosana Local Municipality as well as ignoring the significance of settling people in a safe area that is free from water pollution, sinkholes and underlying dolomite rock left a lot to be desired. The researcher arrived at logical conclusions and recommendations with regard to all aspects related to future management of potable water supply in Khuma Township. / M Development and Management, North-West University, Potchefstroom Campus, 2014
145

Vietinių žaliavų skaldos, skirtos kelių asfaltbetonio dangai įrengti, tyrimai / Research Of Local Stock Breakstore Purposed For Asphalt Concrete Construction

Butėnas, Alfredas 20 June 2006 (has links)
In the work “Research of local stock breakstore purposed for asphalt concrete construction” presents data about hard minerals found and exploited in Lithuania. Minerals used for road building, maintenance and repair are reviewed with a greater focus on minerals used for road building: grit, sand, and dolomite. The paper carries on describing asphalt-concrete coatings and mixtures used for the coatings. The asphalt-concrete mixtures with gravel and dolomite chipping are analyzed. According to their stability, plasticity and porosity (Marshall’s) the usage of mixtures for certain construction class is defined. Is givven a recommendation for using this asphalt concrete mixtures. The major conclusions and the bibliography are presented in the end of the paper.
146

The Pore Structure of Indiana Limestone and Pink Dolomite for the Modeling of Carbon Dioxide in Geologic Carbonate Rock Formations

Freire-Gormaly, Marina 22 November 2013 (has links)
The primary objective was to predict the relative storage capacity of carbonate rocks relevant for carbon dioxide sequestration. To achieve this, a detailed pore scale characterization of model carbonate rocks, Indiana Limestone and Pink Dolomite, was conducted utilizing micro-computed tomography (microCT) data using pore network modeling and invasion percolation simulations. For the first time in literature, Pink Dolomite’s pore space characteristics were analyzed. A secondary objective was to compare thresholding techniques as applied to carbonates which exhibit dual porosity (porosity at multiple length scales). The analysis showed the sensitivity of existing methods to the thresholding technique, imaging method and material. Overall, the contributions of this work provide an assessment of two carbonates relevant for carbon capture and storage at the pore scale; and a preliminary assessment into thresholding dual porosity carbonates.
147

The Pore Structure of Indiana Limestone and Pink Dolomite for the Modeling of Carbon Dioxide in Geologic Carbonate Rock Formations

Freire-Gormaly, Marina 22 November 2013 (has links)
The primary objective was to predict the relative storage capacity of carbonate rocks relevant for carbon dioxide sequestration. To achieve this, a detailed pore scale characterization of model carbonate rocks, Indiana Limestone and Pink Dolomite, was conducted utilizing micro-computed tomography (microCT) data using pore network modeling and invasion percolation simulations. For the first time in literature, Pink Dolomite’s pore space characteristics were analyzed. A secondary objective was to compare thresholding techniques as applied to carbonates which exhibit dual porosity (porosity at multiple length scales). The analysis showed the sensitivity of existing methods to the thresholding technique, imaging method and material. Overall, the contributions of this work provide an assessment of two carbonates relevant for carbon capture and storage at the pore scale; and a preliminary assessment into thresholding dual porosity carbonates.
148

The management of potable water supply in Khuma Township, Matlosana Local Municipality / Kagisho Simon Monnahela

Monnahela, Kagisho Simon January 2014 (has links)
The birth of a non-racial democracy in South Africa brought many challenges such as the supply of potable water to all societies irrespective of their colour or even location. Migration of people from rural to urban has increased the demand of potable water supply in many areas that were previously neglected by the former Apartheid regime. The increase of the human population in urban or developing areas of South Africa will therefore imply that various public services such as potable water supply, proper housing, electricity supply, schooling and basic health facilities should be provided in an efficient, effective and economic manner. As the resident of Khuma Township, the researcher has a keen interest in the management of potable water supply in this area, inter alia, the nature and extent of the physical environment and the efficiency and effectiveness of a potable water supply as a means of improving service delivery by the Matlosana Local Municipality to Khuma Township. The area has the history of gold mining and the majority of the people from other rural areas and neighbouring states moved into this area and were later joined by their families. This resulted in an increase in the population to a point where people were placed in dangerous areas such as underlying dolomite and along the Koekemoer spruit. For example, extension 6 is known to experience sinkholes due to underground mining activities and the underline dolomite rock. The population has increased in Khuma Township to such an extent that a shortage of potable water supply is been experienced. Khuma Township had one water reservoir for the past 40 years and Matlosana Local Municipality did not improve or developed infrastructure related to potable water supply to be able to cater for the increasing population of this area. An empirical study was conducted in among the residents of Khuma Township, Matlosana Local Municipality and role-players in the management of potable water supply. From this study, it was evident that the supply of potable water in Khuma Township is insufficient, and there was poor communication, cooperation and participation between Matlosana Local Municipality and the residents of Khuma Township. The ineffective management of potable water supply in Khuma Township by the Matlosana Local Municipality as well as ignoring the significance of settling people in a safe area that is free from water pollution, sinkholes and underlying dolomite rock left a lot to be desired. The researcher arrived at logical conclusions and recommendations with regard to all aspects related to future management of potable water supply in Khuma Township. / M Development and Management, North-West University, Potchefstroom Campus, 2014
149

Dedolomitization and Alkali-Silica Reactions in Ohio-Sourced Dolostone Aggregates

Smeltz, Jonathan Brett 08 May 2018 (has links)
No description available.
150

[en] EFFECT OF SEA WATER SOLUTION AND SUPERCRITICAL CARBON GAS ON A CALCIUM LIMESTONE / [pt] EFEITO DE UMA SOLUÇÃO DE ÁGUA DO MAR E GÁS CARBÔNICO SUPERCRÍTICO SOBRE UM CALCÁRIO CALCÍTICO

CELSO DE CASTRO MACHADO 28 December 2017 (has links)
[pt] A injeção de fluidos é uma prática comum na indústria de petróleo e um dos objetivos desta operação é aumentar o fator de recuperação dos campos petrolíferos. À medida que o óleo vai sendo produzido há naturalmente perda da quantidade de energia nativa, inerente ao reservatório, que manteria a continuidade da produção. Nesse ponto, fazem-se necessárias intervenções nos poços para dar continuidade à produção, lançando-se mão dos métodos de recuperação, dos quais a injeção de fluidos é um deles. As formulações desses fluidos de injeção são via de regra baseadas na utilização de água do mar (que é rica em magnésio) e em solução supercrítica com gás carbônico oriundo do próprio reservatório. Esses fluidos quando em contato com as rochas carbonáticas do pré-sal, propiciam a uma condição de ambiente químico nunca vivenciada quando este tipo de operação era realizada nos reservatórios nacionais anteriores à exploração no pré-sal. As rochas carbonáticas são reativas e a injeção de fluidos pode provocar alterações tanto na composição mineralógica quanto na composição dos fluidos produzidos. O objetivo deste trabalho é buscar evidências objetivas, identificação e quantificação, da precipitação ao longo do tempo de espécies minerais contendo magnésio formadas a partir de interações de rocha calcária (mais especificamente a calcita (CaCO3)) e fluido de injeção utilizado na recuperação avançada de poços de petróleo. Realizaram-se experimentos em que uma rocha calcária conhecida interagiu com CO2 supercrítico em meio a uma solução salina de água do mar sintética sob condições de temperatura e pressão da ordem de grandeza das encontradas em reservatórios do pré-sal. As amostras de rocha foram expostas ao fluido a 150 graus Celsius e 276 bar sob diferentes tempos de reação. Em seguida foram realizados ensaios de DRX e de composição química elementar (ICP-OES) onde ficou evidenciada a presença de magnésio na calcita após interação com o fluido de injeção, as análises por DRX não conseguiram constatar alterações na estrutura cristalina dessas calcitas pós reação. / [en] Fluid injection is a common practice in oil industry and one of its targets is to increase the recovery factor of oil fields. As the oil is being produced, there is naturally loss in the amount of the reservoir native energy to sustain production. At this point, human intervention is necessary to continue production, so recovery methods are used, of which fluid injection is one of them. These injection fluid formulations are usually based on seawater (which is rich in magnesium) and supercritical carbon dioxide solution from the reservoir itself, which in contact with the pre-salt carbonate rocks will lead to a condition of chemical environment never experienced when this operation was performed in national reservoirs prior to presalt exploration. The carbonate rocks are reactive and fluid injections can cause changes in both mineral composition and produced fluids composition. This work objectives the searching for evidences, identification and quantification, of mineral species precipitation containing magnesium from interactions of limestone (more specifically calcite (CaCO3)) and injection fluid used in the enhanced oil recovery. Experiments were performed in which a known powdered limestone rock interacted with supercritical CO2 in a saline solution of synthetic sea water under tipical conditions (temperature and pressure) found at pre-salt reservoirs. The rock samples were exposed to fluid at 150 Celsius degrees and 276 bar under different reaction times. Then, XRD analysis and elemental chemical composition (ICP-OES) tests were performed, showing the presence of magnesium in the calcite after interaction with the injection fluid, although the XRD analysis failed to verify changes in the crystalline structures of these calcites after reaction.

Page generated in 0.0586 seconds