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Analytical control valve selection for mine water reticulation systems / F.G. Taljaard.Taljaard, Francois George January 2012 (has links)
Some of the largest and deepest mines in the world are situated in South Africa. Underground temperatures and humidity can be controlled by means of complex chilled water reticulation system. A cascade pumping system is used to pump the used water from the underground levels back to the surface.
The dewatering process is energy intensive. Large volumes of water are used during the general mine drilling periods (06:00 to 12:00). During blasting periods (15:00 to 18:00) a minimum amount of personnel are underground, yet large volumes of water are still sent underground due to a lack of control. Reducing the water sent underground, will reduce the amount of water pumped back to the surface; resulting in significant energy savings.
Water flow and pressure can be managed by installing control valves at appropriate positions throughout the water reticulation system. Selecting a control valve is typically governed by constraints such as cavitation, water hammer, flashing, safety ratings and control range. A basic set of calculations can be used to determine whether a valve conforms to a specific scenario. However, scenarios calculated by engineers are not indicative of all applied system scenarios.
When control valves are installed, to optimise the operation of a system, it affects the system’s characteristics. Sampled system data will therefore no longer provide adequate readings to help with selecting the correct control valve. An analytical control valve selection method has been developed and implemented. The case study shows the results and practical implications of applying this method in the mining industry. Implementing the analytical valve selection method is shown to be viable, realising electrical energy cost savings for the mine by reducing power requirements from Eskom. Analytical control valve selection for mine water reticulation systems / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.
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Analytical control valve selection for mine water reticulation systems / F.G. Taljaard.Taljaard, Francois George January 2012 (has links)
Some of the largest and deepest mines in the world are situated in South Africa. Underground temperatures and humidity can be controlled by means of complex chilled water reticulation system. A cascade pumping system is used to pump the used water from the underground levels back to the surface.
The dewatering process is energy intensive. Large volumes of water are used during the general mine drilling periods (06:00 to 12:00). During blasting periods (15:00 to 18:00) a minimum amount of personnel are underground, yet large volumes of water are still sent underground due to a lack of control. Reducing the water sent underground, will reduce the amount of water pumped back to the surface; resulting in significant energy savings.
Water flow and pressure can be managed by installing control valves at appropriate positions throughout the water reticulation system. Selecting a control valve is typically governed by constraints such as cavitation, water hammer, flashing, safety ratings and control range. A basic set of calculations can be used to determine whether a valve conforms to a specific scenario. However, scenarios calculated by engineers are not indicative of all applied system scenarios.
When control valves are installed, to optimise the operation of a system, it affects the system’s characteristics. Sampled system data will therefore no longer provide adequate readings to help with selecting the correct control valve. An analytical control valve selection method has been developed and implemented. The case study shows the results and practical implications of applying this method in the mining industry. Implementing the analytical valve selection method is shown to be viable, realising electrical energy cost savings for the mine by reducing power requirements from Eskom. Analytical control valve selection for mine water reticulation systems / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.
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Utilizing GIS for effective datamodel design at the NWU Potchefstroom Campus / David Andreas MareeMaree, David Andreas January 2011 (has links)
Record keeping and management of electrical utilities inside buildings is an important aspect
to ensure effective electrical distribution. The ability to find the location of each electrical
feature inside a building and extract information about it helps to solve network problems
faster. The use of a spatial database structure facilitates the maintenance and general
operations of an electrical network across different buildings.
The aim of this study is to design and develop a 3D data model to provide a management
system for electrical utilities inside buildings. The geodatabase provides integrated
information between different electrical components forming the network inside the specified
buildings in the study area.
A prototype called the PUK geodatabase was designed and developed for the NWU
Potchefstroom Campus as a 3D data model. The data model consists of raster and vector data
used in network datasets, relationship classes and topology rules. The aim of this project was
accomplished through the 3D analysis capabilities of the model. The research determined
that the prototype called the PUK geodatabase can be utilized as a 3D management system
for electrical utilities across the different floor levels of a building. / Thesis (M.Sc. (Geography and Environmental Studies))--North-West University, Potchefstroom Campus, 2012
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Comparing network coding implementations on different OSI layers / Jacobus Leendert van WykVan Wyk, Jacobus Leendert January 2010 (has links)
Network coding is a technique used to increase the capacity of a network by combining messages
sent over the network. The combined messages could be separated by using sufficient original
messages which were used to combine the messages. Network coding can be implemented in
different layers of the 051 stack, but to date a complete comparison between different
implementations of network coding has not been done.
The goal of this dissertation is to implement a wireless node model with network coding in the MAC
layer and evaluate the performance characteristics of reference networks that implement the new
node model. This will serve as the first step of a greater goal, namely finding the most favourable
position in the 051 stack to implement network coding. The characteristics of the different
implementations of network coding are presented in this dissertation. Simulations were done in
OPNET® to find further attributes concerning the implementation of network coding in the MAC
layer.
The simulation process used is presented and explained, and the results from the simulations are
analysed. Network coding in the simulations was implemented opportunistically. The results show
that the more often different nodes send frames to the coding node, the better network coding
performs.
The work contributes to finding the best layer for implementing network coding for its increased
throughput. A benchmark network was created so that network coding could be implemented in all
the layers of the 051 stack, and then be compared to each other. An implementation of network
coding in the MAC layer was simulated and analyzed.
We conclude that, because there are so many different purposes for which networks are used, a
single instance of network coding is unlikely to be similarly beneficial to all purposes. There still
remains work to find the most favourable position for network coding in the 051 stack for all the
different types of network coding. / Thesis (M. Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011
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Utilizing GIS for effective datamodel design at the NWU Potchefstroom Campus / David Andreas MareeMaree, David Andreas January 2011 (has links)
Record keeping and management of electrical utilities inside buildings is an important aspect
to ensure effective electrical distribution. The ability to find the location of each electrical
feature inside a building and extract information about it helps to solve network problems
faster. The use of a spatial database structure facilitates the maintenance and general
operations of an electrical network across different buildings.
The aim of this study is to design and develop a 3D data model to provide a management
system for electrical utilities inside buildings. The geodatabase provides integrated
information between different electrical components forming the network inside the specified
buildings in the study area.
A prototype called the PUK geodatabase was designed and developed for the NWU
Potchefstroom Campus as a 3D data model. The data model consists of raster and vector data
used in network datasets, relationship classes and topology rules. The aim of this project was
accomplished through the 3D analysis capabilities of the model. The research determined
that the prototype called the PUK geodatabase can be utilized as a 3D management system
for electrical utilities across the different floor levels of a building. / Thesis (M.Sc. (Geography and Environmental Studies))--North-West University, Potchefstroom Campus, 2012
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Sequence variation of the amelogenin gene on the Y-chromosome / by Irma FerreiraFerreira, Irma January 2010 (has links)
The accurate determination of gender of biological samples has valuable applications in
medical and forensic investigations. Gender determination based on length variations in
the X-Y homologous amelogenin gene, is part of most commercial multiplex DNA profiling
kits. The first report of a failure of the amelogenin sex test was in 1998 when two normal
males were typed as female. Subsequently, several amelogenin Y (AMELY) negative
males have been reported. This study represents the first report of this phenomenon in the
black South African population.
This study determined the size of the Y-chromosome deletion that resulted in the failure of
the amelogenin sex test in two black South African AMELY-negative males by typing
specific DNA markers surrounding the amelogenin locus. Through deletion size and
Y-chromosome microsatellite haplotypes, the relationship between the samples was
investigated. The samples were sequenced at the amelogenin gene and typed for thirteen
sites on the short arm of the Y-chromosome. In order to determine the Y-chromosome
haplotypes, eleven Y-chromosome microsatellite markers were typed.
These samples had the same size deletion of approximately 3 Mb. The Y-chromosome
haplotypes indicated that these were probably independent events. The frequency of
AMELY-negative males is rare in this population sample of 8,344 individuals, with a
frequency of 0.065% in the black South African sample population. Notwithstanding, tests
performed for detecting the presence of male DNA based on the presence of the
amelogenin gene alone should be reconsidered, as this study confirms that these
deletions do occur in the African population. The impact of the results generated in this
study on the medical and forensic practise of DNA testing is significant. / Thesis (Ph.D. (Biochemistry))--North-West University, Potchefstroom Campus, 2011.
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Applying tree knapsack approaches to general network design : a case study / T. BaitshenyetsiBaitshenyetsi, Tumo January 2010 (has links)
There are many practical decision problems that fall into the category of network flow problems: numerous examples of applications can be found in areas such as telecommunications, logistics, distributions, engineering, computer science and so on. One of the most popular and valuable tools to solve network flow problems of a topological nature is the use of linear programming models. An important extension of these models is that of integer programming models that deal with problems where some, or all, of the variables are required to assume integer variables. A significant application in this class of problems is the knapsack problem that arises in different contexts such as loading containers in aircraft or satisfying the demand for various lengths of cloth which must be cut from fixed length bolts of fabric.
In this study, the feasibility of representing a network flow model in a tree network model and subsequently solving it using a tree knapsack approach is investigated. To compare and validate the proposed technique, a specific case study was chosen from the literature that can be used as a basis for the research project. The said study was an oil pipeline design problem, addressed by Brimberg et al. (2003). This focuses on the optimal design of an oil pipeline network for the South Gabon oil field in Africa. The objective was to reduce oil transportation costs to a major port. Following an overview of different network flow and knapsack models, an overview of the said matter is presented. A description of the proposed tree knapsack approach and the application of this approach to the given problem is given. Results have indicated that it is feasible to apply a tree knapsack approach to solve network flow problems. / Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2011.
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Sequence variation of the amelogenin gene on the Y-chromosome / by Irma FerreiraFerreira, Irma January 2010 (has links)
The accurate determination of gender of biological samples has valuable applications in
medical and forensic investigations. Gender determination based on length variations in
the X-Y homologous amelogenin gene, is part of most commercial multiplex DNA profiling
kits. The first report of a failure of the amelogenin sex test was in 1998 when two normal
males were typed as female. Subsequently, several amelogenin Y (AMELY) negative
males have been reported. This study represents the first report of this phenomenon in the
black South African population.
This study determined the size of the Y-chromosome deletion that resulted in the failure of
the amelogenin sex test in two black South African AMELY-negative males by typing
specific DNA markers surrounding the amelogenin locus. Through deletion size and
Y-chromosome microsatellite haplotypes, the relationship between the samples was
investigated. The samples were sequenced at the amelogenin gene and typed for thirteen
sites on the short arm of the Y-chromosome. In order to determine the Y-chromosome
haplotypes, eleven Y-chromosome microsatellite markers were typed.
These samples had the same size deletion of approximately 3 Mb. The Y-chromosome
haplotypes indicated that these were probably independent events. The frequency of
AMELY-negative males is rare in this population sample of 8,344 individuals, with a
frequency of 0.065% in the black South African sample population. Notwithstanding, tests
performed for detecting the presence of male DNA based on the presence of the
amelogenin gene alone should be reconsidered, as this study confirms that these
deletions do occur in the African population. The impact of the results generated in this
study on the medical and forensic practise of DNA testing is significant. / Thesis (Ph.D. (Biochemistry))--North-West University, Potchefstroom Campus, 2011.
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Applying tree knapsack approaches to general network design : a case study / T. BaitshenyetsiBaitshenyetsi, Tumo January 2010 (has links)
There are many practical decision problems that fall into the category of network flow problems: numerous examples of applications can be found in areas such as telecommunications, logistics, distributions, engineering, computer science and so on. One of the most popular and valuable tools to solve network flow problems of a topological nature is the use of linear programming models. An important extension of these models is that of integer programming models that deal with problems where some, or all, of the variables are required to assume integer variables. A significant application in this class of problems is the knapsack problem that arises in different contexts such as loading containers in aircraft or satisfying the demand for various lengths of cloth which must be cut from fixed length bolts of fabric.
In this study, the feasibility of representing a network flow model in a tree network model and subsequently solving it using a tree knapsack approach is investigated. To compare and validate the proposed technique, a specific case study was chosen from the literature that can be used as a basis for the research project. The said study was an oil pipeline design problem, addressed by Brimberg et al. (2003). This focuses on the optimal design of an oil pipeline network for the South Gabon oil field in Africa. The objective was to reduce oil transportation costs to a major port. Following an overview of different network flow and knapsack models, an overview of the said matter is presented. A description of the proposed tree knapsack approach and the application of this approach to the given problem is given. Results have indicated that it is feasible to apply a tree knapsack approach to solve network flow problems. / Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2011.
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Comparing network coding implementations on different OSI layers / Jacobus Leendert van WykVan Wyk, Jacobus Leendert January 2010 (has links)
Network coding is a technique used to increase the capacity of a network by combining messages
sent over the network. The combined messages could be separated by using sufficient original
messages which were used to combine the messages. Network coding can be implemented in
different layers of the 051 stack, but to date a complete comparison between different
implementations of network coding has not been done.
The goal of this dissertation is to implement a wireless node model with network coding in the MAC
layer and evaluate the performance characteristics of reference networks that implement the new
node model. This will serve as the first step of a greater goal, namely finding the most favourable
position in the 051 stack to implement network coding. The characteristics of the different
implementations of network coding are presented in this dissertation. Simulations were done in
OPNET® to find further attributes concerning the implementation of network coding in the MAC
layer.
The simulation process used is presented and explained, and the results from the simulations are
analysed. Network coding in the simulations was implemented opportunistically. The results show
that the more often different nodes send frames to the coding node, the better network coding
performs.
The work contributes to finding the best layer for implementing network coding for its increased
throughput. A benchmark network was created so that network coding could be implemented in all
the layers of the 051 stack, and then be compared to each other. An implementation of network
coding in the MAC layer was simulated and analyzed.
We conclude that, because there are so many different purposes for which networks are used, a
single instance of network coding is unlikely to be similarly beneficial to all purposes. There still
remains work to find the most favourable position for network coding in the 051 stack for all the
different types of network coding. / Thesis (M. Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011
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