Project management in an environmentally sensitive South African mining environment
- Authors: Cathey, Steve William
- Date: 2018
- Subjects: Mineral industries - Social aspects - South Africa , Social responsibility of business - South Africa , Project management - South Africa , Cemeteries - South Africa , Exhumation - South Africa
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/293705 , uj:31942
- Description: D.Ing. (Engineering Management) , Abstract: In order to more efficiently manage and track progress, large projects are divided into three main steps, namely: Initiation, Implementation, Termination. Using systematic, empirically based, scientific procedures, the aim of this research is to identify, examine and explain how a grave relocation project impacts a typical mining project through each of the three project steps. By means of a case study, it will then examine the interventions required to successfully integrate a grave relocation project as part of an operating mining project. In addition, it will also examine the inter-relationships between the project, the local communities and present legislation in regard to executing a grave relocation project following the steps that were captured during the case study. In this way, reliable and replicable data will be generated, which can, in turn, be added to, interpreted and or implemented in other projects of a similar nature in the sensitive South African mining environment. Until very recently, grave relocation would not have been considered to be a necessary part of a normal mining project. However, due to increasing urbanisation (Giraut F, 2009) and the fluidity of the political and financial situation of South Africa, the dynamics in the relationship between new mining projects and surrounding local communities have undergone many changes and have become more complex. This includes matters such as grave relocation. Consequently, it has become necessary for the mining industry not only to more fully understand the legislation in regard to matters such as grave relocation, but also to take cognizance of the wider issues and potential impacts, on both present and future mining activities. Experience has indicated that project planning, time and cost control, communication within the local community, monitoring and control of on-site and off-site work and quality control can all be directly affected...
- Full Text:
- Authors: Cathey, Steve William
- Date: 2018
- Subjects: Mineral industries - Social aspects - South Africa , Social responsibility of business - South Africa , Project management - South Africa , Cemeteries - South Africa , Exhumation - South Africa
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/293705 , uj:31942
- Description: D.Ing. (Engineering Management) , Abstract: In order to more efficiently manage and track progress, large projects are divided into three main steps, namely: Initiation, Implementation, Termination. Using systematic, empirically based, scientific procedures, the aim of this research is to identify, examine and explain how a grave relocation project impacts a typical mining project through each of the three project steps. By means of a case study, it will then examine the interventions required to successfully integrate a grave relocation project as part of an operating mining project. In addition, it will also examine the inter-relationships between the project, the local communities and present legislation in regard to executing a grave relocation project following the steps that were captured during the case study. In this way, reliable and replicable data will be generated, which can, in turn, be added to, interpreted and or implemented in other projects of a similar nature in the sensitive South African mining environment. Until very recently, grave relocation would not have been considered to be a necessary part of a normal mining project. However, due to increasing urbanisation (Giraut F, 2009) and the fluidity of the political and financial situation of South Africa, the dynamics in the relationship between new mining projects and surrounding local communities have undergone many changes and have become more complex. This includes matters such as grave relocation. Consequently, it has become necessary for the mining industry not only to more fully understand the legislation in regard to matters such as grave relocation, but also to take cognizance of the wider issues and potential impacts, on both present and future mining activities. Experience has indicated that project planning, time and cost control, communication within the local community, monitoring and control of on-site and off-site work and quality control can all be directly affected...
- Full Text:
Analise op dempers en skokbrekers
- Labuschagne, Leonardus Johannes
- Authors: Labuschagne, Leonardus Johannes
- Date: 2015-11-10
- Subjects: Shock absorbers , Spare parts , Machine parts
- Type: Thesis
- Identifier: uj:14532 , http://hdl.handle.net/10210/15063
- Description: B.Ing. (Mechanical Engineering) , Please refer to full text to view abstract
- Full Text:
- Authors: Labuschagne, Leonardus Johannes
- Date: 2015-11-10
- Subjects: Shock absorbers , Spare parts , Machine parts
- Type: Thesis
- Identifier: uj:14532 , http://hdl.handle.net/10210/15063
- Description: B.Ing. (Mechanical Engineering) , Please refer to full text to view abstract
- Full Text:
Implementation of a quality management system for a consulting engineering practice
- Authors: Jansen, Monro J.
- Date: 2015-09-22
- Subjects: Consulting engineers - Quality control , Total quality management
- Type: Thesis
- Identifier: uj:14149 , http://hdl.handle.net/10210/14593
- Description: M.Ing. , Please refer to full text to view abstract
- Full Text:
- Authors: Jansen, Monro J.
- Date: 2015-09-22
- Subjects: Consulting engineers - Quality control , Total quality management
- Type: Thesis
- Identifier: uj:14149 , http://hdl.handle.net/10210/14593
- Description: M.Ing. , Please refer to full text to view abstract
- Full Text:
Relationships in the professional team on construction projects
- Authors: Van Heerden, Etienne
- Date: 2015-09-01
- Subjects: Construction industry - Employees - Psychology , Interpersonal relations , Industrial relations , Trust
- Type: Thesis
- Identifier: uj:14021 , http://hdl.handle.net/10210/14392
- Description: M.Ing. , The engineering construction industry is one that is synonymous with high production, tight schedules, strict cost control and in general high working pressure. Construction is an industry that is generally occupied with technical personnel. It is also an industry where interaction and communication between people is important to improve the chances of success of the project...
- Full Text:
- Authors: Van Heerden, Etienne
- Date: 2015-09-01
- Subjects: Construction industry - Employees - Psychology , Interpersonal relations , Industrial relations , Trust
- Type: Thesis
- Identifier: uj:14021 , http://hdl.handle.net/10210/14392
- Description: M.Ing. , The engineering construction industry is one that is synonymous with high production, tight schedules, strict cost control and in general high working pressure. Construction is an industry that is generally occupied with technical personnel. It is also an industry where interaction and communication between people is important to improve the chances of success of the project...
- Full Text:
Management for growth in the textile industry : a case study
- Authors: Sesli, Ferah
- Date: 2015-03-19
- Subjects: Textile industry - Management , Strategic planning
- Type: Thesis
- Identifier: uj:13511 , http://hdl.handle.net/10210/13541
- Description: M.Phil. (Engineering Management) , Please refer to full text to view abstract
- Full Text:
- Authors: Sesli, Ferah
- Date: 2015-03-19
- Subjects: Textile industry - Management , Strategic planning
- Type: Thesis
- Identifier: uj:13511 , http://hdl.handle.net/10210/13541
- Description: M.Phil. (Engineering Management) , Please refer to full text to view abstract
- Full Text:
Aspekte van vibrasies in romp- en buis hitteruilers
- Jordaan, Christiaan Cornelius
- Authors: Jordaan, Christiaan Cornelius
- Date: 2015-02-12
- Subjects: Heat - Transmission , Turbulence , Eddies
- Type: Thesis
- Identifier: uj:13303 , http://hdl.handle.net/10210/13320
- Description: M.Ing. (Mechanical Engineering) , Shell and tube heat exchangers are commonly used in industrial processes. In the heat exchangers the tubes incur flow induced vibrations. These vibrations lead to fretting on the perimeter of the tube at the baffle plates and to fatigue failure at the tube sheets. Various studies were and are done to qualify and quantify these vibrations. This is then used to develop design criteria and methods for lowering the vibration amplitudes of the tubes. In the thesis the response of a tube bundle in cross flow is shown. The effect of increasing cross flow velocity on the vibration amplitude of the tubes is determined in a low speed wind tunnel. The results show similarity to the work done by Gorman [27]. By raising the natural frequency of the tubes in the first row upstream it is shown that the vibration peaks exhibited by the unmodified model.at cross flow velocities lower than the critical flow speed do not materialize in the modified tube bundle. This modification can be implemented by decreasing the unsupported length of the tubes in the first row. The inclusion of fluid damping when calculating the total damping of the tubes according to Blevins [24] is shown in the experiment. From experimental results it is shown that the prediction of the critical velocity according to Blevins [24] results in a better prediction of this velocity. Numerical solutions of two dimensional flow over a single cylinder and a pair of cylinders are obtained by simulating the flow on the STAR CD flow simulation package. The effect of neighbouring tubes on one another is determined by qualifying and quantifying the flow over and the forces on the tubes. The vortex shedding frequency determined from the simulation coincides with experimental results. This shows great potential in future simulation of flow over a tube bundle. A computerised design model is also developed. Themodel determines the vibration potential of the tube bundle in a shell and tube heat exchanger. If needed, modifications to new designs and built heat exchangers can be done and the vibration potential is easily determined with the model. The results of the experimental work are used to further develop the design criteria preventing detrimental vibrations in heat exchangers. Promising results to decrease vibration amplitudes of tubes in tube bundles are obtained in the experiments done. This and the results obtained in the simulation of the vortex shedding frequencies that coincide with the results in the experimental work, show great potential for flow simulation and development of methods to decrease flow induced vibrations of tubes in shell and tube heat exchangers.
- Full Text:
- Authors: Jordaan, Christiaan Cornelius
- Date: 2015-02-12
- Subjects: Heat - Transmission , Turbulence , Eddies
- Type: Thesis
- Identifier: uj:13303 , http://hdl.handle.net/10210/13320
- Description: M.Ing. (Mechanical Engineering) , Shell and tube heat exchangers are commonly used in industrial processes. In the heat exchangers the tubes incur flow induced vibrations. These vibrations lead to fretting on the perimeter of the tube at the baffle plates and to fatigue failure at the tube sheets. Various studies were and are done to qualify and quantify these vibrations. This is then used to develop design criteria and methods for lowering the vibration amplitudes of the tubes. In the thesis the response of a tube bundle in cross flow is shown. The effect of increasing cross flow velocity on the vibration amplitude of the tubes is determined in a low speed wind tunnel. The results show similarity to the work done by Gorman [27]. By raising the natural frequency of the tubes in the first row upstream it is shown that the vibration peaks exhibited by the unmodified model.at cross flow velocities lower than the critical flow speed do not materialize in the modified tube bundle. This modification can be implemented by decreasing the unsupported length of the tubes in the first row. The inclusion of fluid damping when calculating the total damping of the tubes according to Blevins [24] is shown in the experiment. From experimental results it is shown that the prediction of the critical velocity according to Blevins [24] results in a better prediction of this velocity. Numerical solutions of two dimensional flow over a single cylinder and a pair of cylinders are obtained by simulating the flow on the STAR CD flow simulation package. The effect of neighbouring tubes on one another is determined by qualifying and quantifying the flow over and the forces on the tubes. The vortex shedding frequency determined from the simulation coincides with experimental results. This shows great potential in future simulation of flow over a tube bundle. A computerised design model is also developed. Themodel determines the vibration potential of the tube bundle in a shell and tube heat exchanger. If needed, modifications to new designs and built heat exchangers can be done and the vibration potential is easily determined with the model. The results of the experimental work are used to further develop the design criteria preventing detrimental vibrations in heat exchangers. Promising results to decrease vibration amplitudes of tubes in tube bundles are obtained in the experiments done. This and the results obtained in the simulation of the vortex shedding frequencies that coincide with the results in the experimental work, show great potential for flow simulation and development of methods to decrease flow induced vibrations of tubes in shell and tube heat exchangers.
- Full Text:
A systematic approach towards the implementation of an effective management model for gland service
- Authors: Robinson, Gavin Stuart
- Date: 2015
- Subjects: Engineering - Management , Engineering systems , Tailings dams
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/225150 , uj:22733
- Description: Abstract: This dissertation develops and evaluates a model for the effective management of a typical gland service system, utilising engineering management technology, for a wide variety of mining applications to innovatively create a method for the correct implementation and maintenance of a gland service system. A Systematic Engineering approach will organise segmented processes that will focus the design of an Effective Management Model (EMM) for a Gland Service System (GSS). The approach will focus on the optimisation of the GSS which is a fundamental pillar for the functionality of the slurry pumps in a tailings plant. A Production Performance Model (PPM) will be created utilising the Overall Equipment Effectiveness (OEE) Theory to provide an indication of the production capacity of a tailings plant. The subsystem of the PPM will be the EMM; its core focus is on the optimisation of the Gland Service System, which in turn directly relates the improved performance of the tailings plant which ultimately results in the improved capability of the mines production process. Today’s competitive environment compels businesses to find ways and means to effectively conduct projects in order to satisfy the ever increasing expectations of clients. Cohesion with Systematic Engineering Approach and Engineering Management theory, while including some mechanical engineering concepts such as manufacturing enhancements and performance optimisation, have been applied in the operational structure of a typical gland service system. The unique case study presented provides an opportunity to practically apply these various management techniques, while referring to mechanical engineering practises, in a mining environment to provide an effective management model for the optimum operation of a Gland Service System. Mines located in various locations within South Africa were utilised in the case study. Simulink has been applied to model and simulate the environment where these engineering management techniques have been applied. Theories such as OEE were used to create the foundation of the model for the PPM. The subsystem of the PPM is the EMM and Simulink was used to incorporate the optimisation inputs, thus forming a model from Qualitative and Quantitative feedback, using triangulation of the two data sampling systems. The combination of non-probability sampling, and purpose sampling systems formed the basis of the triangulation system. Together with practical experimentation findings and the participants’ feedback, the EMM basis was constructed. , D.Ing. (Engineering Management)
- Full Text:
- Authors: Robinson, Gavin Stuart
- Date: 2015
- Subjects: Engineering - Management , Engineering systems , Tailings dams
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/225150 , uj:22733
- Description: Abstract: This dissertation develops and evaluates a model for the effective management of a typical gland service system, utilising engineering management technology, for a wide variety of mining applications to innovatively create a method for the correct implementation and maintenance of a gland service system. A Systematic Engineering approach will organise segmented processes that will focus the design of an Effective Management Model (EMM) for a Gland Service System (GSS). The approach will focus on the optimisation of the GSS which is a fundamental pillar for the functionality of the slurry pumps in a tailings plant. A Production Performance Model (PPM) will be created utilising the Overall Equipment Effectiveness (OEE) Theory to provide an indication of the production capacity of a tailings plant. The subsystem of the PPM will be the EMM; its core focus is on the optimisation of the Gland Service System, which in turn directly relates the improved performance of the tailings plant which ultimately results in the improved capability of the mines production process. Today’s competitive environment compels businesses to find ways and means to effectively conduct projects in order to satisfy the ever increasing expectations of clients. Cohesion with Systematic Engineering Approach and Engineering Management theory, while including some mechanical engineering concepts such as manufacturing enhancements and performance optimisation, have been applied in the operational structure of a typical gland service system. The unique case study presented provides an opportunity to practically apply these various management techniques, while referring to mechanical engineering practises, in a mining environment to provide an effective management model for the optimum operation of a Gland Service System. Mines located in various locations within South Africa were utilised in the case study. Simulink has been applied to model and simulate the environment where these engineering management techniques have been applied. Theories such as OEE were used to create the foundation of the model for the PPM. The subsystem of the PPM is the EMM and Simulink was used to incorporate the optimisation inputs, thus forming a model from Qualitative and Quantitative feedback, using triangulation of the two data sampling systems. The combination of non-probability sampling, and purpose sampling systems formed the basis of the triangulation system. Together with practical experimentation findings and the participants’ feedback, the EMM basis was constructed. , D.Ing. (Engineering Management)
- Full Text:
'n Aanpasbare energieabsorbeerder vir 'n helikoptersitplek
- Authors: Coetzee, Gerhard
- Date: 2014-09-16
- Subjects: Airplanes - Seats , Hydraulic structures - Design and construction , Hydraulic engineering
- Type: Thesis
- Identifier: uj:12314 , http://hdl.handle.net/10210/12100
- Description: M.Ing. (Mechanical Engineering) , The development of crashworthy seats for helicopters during the past three decades is discussed. The primary design criteria is mentioned and the disadvantages of crashworthy seats that are currently in use are highlighted. An hydraulic energy absorber which automatically compensates for the mass of the seat occupant was designed and a simulation model was developed. The concept for the control valve used was obtained from WARRICK [25]. Results of the simulations correlated well with those of WARRICK. A prototype of a mechanical/hydraulic accelerometer was designed, manufactured and tested. The results obtained from the experiments compared favourably with simulation values. The simulated and experimental results indicate that the concept of using an hydraulic energy absorber, in a crashworthy seat, is very satisfactory. Future crashworthy seat designs could be enhanced by incorporating this promising device.
- Full Text:
- Authors: Coetzee, Gerhard
- Date: 2014-09-16
- Subjects: Airplanes - Seats , Hydraulic structures - Design and construction , Hydraulic engineering
- Type: Thesis
- Identifier: uj:12314 , http://hdl.handle.net/10210/12100
- Description: M.Ing. (Mechanical Engineering) , The development of crashworthy seats for helicopters during the past three decades is discussed. The primary design criteria is mentioned and the disadvantages of crashworthy seats that are currently in use are highlighted. An hydraulic energy absorber which automatically compensates for the mass of the seat occupant was designed and a simulation model was developed. The concept for the control valve used was obtained from WARRICK [25]. Results of the simulations correlated well with those of WARRICK. A prototype of a mechanical/hydraulic accelerometer was designed, manufactured and tested. The results obtained from the experiments compared favourably with simulation values. The simulated and experimental results indicate that the concept of using an hydraulic energy absorber, in a crashworthy seat, is very satisfactory. Future crashworthy seat designs could be enhanced by incorporating this promising device.
- Full Text:
'n Parametriese studie van 'n roterende stelsel met oliefilmdempers
- Authors: Roberts, Johan George
- Date: 2014-09-16
- Subjects: Rotors - Dynamics , Rotors
- Type: Thesis
- Identifier: uj:12313 , http://hdl.handle.net/10210/12099
- Description: M.Ing. (Mechanical Engineering) , This thesis is about the design of a suitable suspension system for a high-speed machine. Experimental parametric analyses of some aspects of the design are presented. Some rotordynamic aspects which are addressed include the following: Undamped lateral critical speed analysis in order to determine the stiffness requirements for the suspension system of the machine. Calculation of optimum damping for the rotating system and an experimental evaluation of the amount of damping on the dynamic behaviour of the machine. Design of the suspension system from a dynamics point of view. Design of a test rig to evaluate the performance of the squeeze-film damper. Experimental parametric evaluation of a squeeze-film damper without seals or oil supply groove.
- Full Text:
- Authors: Roberts, Johan George
- Date: 2014-09-16
- Subjects: Rotors - Dynamics , Rotors
- Type: Thesis
- Identifier: uj:12313 , http://hdl.handle.net/10210/12099
- Description: M.Ing. (Mechanical Engineering) , This thesis is about the design of a suitable suspension system for a high-speed machine. Experimental parametric analyses of some aspects of the design are presented. Some rotordynamic aspects which are addressed include the following: Undamped lateral critical speed analysis in order to determine the stiffness requirements for the suspension system of the machine. Calculation of optimum damping for the rotating system and an experimental evaluation of the amount of damping on the dynamic behaviour of the machine. Design of the suspension system from a dynamics point of view. Design of a test rig to evaluate the performance of the squeeze-film damper. Experimental parametric evaluation of a squeeze-film damper without seals or oil supply groove.
- Full Text:
The analysis of runaway escapements utilised in clockwork mechanisms
- Authors: Mundy, Wayne Russell
- Date: 2014-07-31
- Subjects: Mechanical engineering
- Type: Thesis
- Identifier: uj:11935 , http://hdl.handle.net/10210/11663
- Description: M. Ing. (Mechanical Engineering) , Runaway escapements of various types are utilised as timing regulators or inertial governors in clockwork mechanisms. This work developed a computer simulation of a spring driven runaway escapement having a flat sided pallet. The mathematical analysis took into account the three motion regimes of the escapement, that is, coupled motion, free motion and impact, and allows for equal and unequal arm pallets and pallets with arbitrarily located centres of mass. Rotor disc friction was also taken into account. Three escapement types were designed using geometric design principles developed. Two of these escapements were then manufactured and tested for arming time on a specially built test base. Simulation runs using the dimensions of these escapements were in excellent agreement with the experimental results. The simulation model was found to be well suited for conducting parametric studies of the spring driven escapement.
- Full Text:
- Authors: Mundy, Wayne Russell
- Date: 2014-07-31
- Subjects: Mechanical engineering
- Type: Thesis
- Identifier: uj:11935 , http://hdl.handle.net/10210/11663
- Description: M. Ing. (Mechanical Engineering) , Runaway escapements of various types are utilised as timing regulators or inertial governors in clockwork mechanisms. This work developed a computer simulation of a spring driven runaway escapement having a flat sided pallet. The mathematical analysis took into account the three motion regimes of the escapement, that is, coupled motion, free motion and impact, and allows for equal and unequal arm pallets and pallets with arbitrarily located centres of mass. Rotor disc friction was also taken into account. Three escapement types were designed using geometric design principles developed. Two of these escapements were then manufactured and tested for arming time on a specially built test base. Simulation runs using the dimensions of these escapements were in excellent agreement with the experimental results. The simulation model was found to be well suited for conducting parametric studies of the spring driven escapement.
- Full Text:
An analysis of hydrodynamic torque converters for design applications in heavy vehicles.
- Authors: Groiss, Friederich Harald
- Date: 2014-06-10
- Subjects: Torque - Measurement , Actuators , Mechanical engineering
- Type: Thesis
- Identifier: uj:11434 , http://hdl.handle.net/10210/11130
- Description: M.Ing. (Mechanical Engineering) , The automotive driveline design engineer is invariably confronted with a limited range of driveline components , the combination of which can result in a design which is far from optimal for vehicle overall performance. Due to the close interaction between the prime mover and the torque converter of an automotive driveline incorporating an automatic transmission , the requirement developed to be able to design or modify a torque converter to attain more optimal prime mover/torque converter interaction. Two torque converters of similar configuration formed the basis of this study. A test bench was developed to verifythe published characteristic of the torque converters under controlled conditions. A computer program was developed to analyse the performance of the specific torque converters. This program is similar to the program developed by Lamprecht [10] , which was further refined by the Buro of Mechanical Engineering at the University of Stellenbosch. A method was established to enable accurate and consistent geometry measurement of torque converters. The analysis program was evaluated by establishing the correlation between the theoretical and published results. Based on the results further refinement was done to the analysis program. A parametric study was done based on the geometry of the larger capacity torque converter. Five components (two impellers, two turbines and a single stator) of alternative design but interchangeable with the standard components, were designed and manufactured, These components were fitted individually and tested on the test bench to establish the correlation between the experimental results and design calculations. Recommendations for further development In the field of hydrodynamic torque converters are made
- Full Text:
- Authors: Groiss, Friederich Harald
- Date: 2014-06-10
- Subjects: Torque - Measurement , Actuators , Mechanical engineering
- Type: Thesis
- Identifier: uj:11434 , http://hdl.handle.net/10210/11130
- Description: M.Ing. (Mechanical Engineering) , The automotive driveline design engineer is invariably confronted with a limited range of driveline components , the combination of which can result in a design which is far from optimal for vehicle overall performance. Due to the close interaction between the prime mover and the torque converter of an automotive driveline incorporating an automatic transmission , the requirement developed to be able to design or modify a torque converter to attain more optimal prime mover/torque converter interaction. Two torque converters of similar configuration formed the basis of this study. A test bench was developed to verifythe published characteristic of the torque converters under controlled conditions. A computer program was developed to analyse the performance of the specific torque converters. This program is similar to the program developed by Lamprecht [10] , which was further refined by the Buro of Mechanical Engineering at the University of Stellenbosch. A method was established to enable accurate and consistent geometry measurement of torque converters. The analysis program was evaluated by establishing the correlation between the theoretical and published results. Based on the results further refinement was done to the analysis program. A parametric study was done based on the geometry of the larger capacity torque converter. Five components (two impellers, two turbines and a single stator) of alternative design but interchangeable with the standard components, were designed and manufactured, These components were fitted individually and tested on the test bench to establish the correlation between the experimental results and design calculations. Recommendations for further development In the field of hydrodynamic torque converters are made
- Full Text:
Mechanical oscillations on overhead transmission lines
- Authors: Du Plessis, Pieter
- Date: 2014-05-08
- Subjects: Overhead electric lines , Telecommunication lines
- Type: Thesis
- Identifier: uj:10966 , http://hdl.handle.net/10210/10539
- Description: D.Ing. (Mechanical Engineering) , This research proposed to develop a mathematical model for the prediction of aeolian vibration levels on overhead transmission lines in order to be able to ensure that damping systems are designed optimally in future. In order to enhance the understanding of aeolian and wake-induced vibration further, it also proposed to implement and apply the fluid flow simulation technique of Computational Fluid Dynamics (CFD) to both single conductors and conductor bundles. The Introduction of the CFD tool to the field of transmission line vibration, will ensure that bundles could be optimally designed for future applications. Wind-induced vibrations are known to cause expensive damage to the conductors and related hardware through fatigue or clashing of the bundled conductors. The primary cause of conductor aeolian vibration is the alternate shedding of wind-induced eddies from the top and bottom sides of the conductor, whereas wake-induced oscillations is peculiar to bundled conductors and arises from effects of the shielding of leeward conductors in bundles by windward ones. In order to study the phenomenon of aeolian vibration, research was undertaken utilising a full scale transmission line test station close to Kroonstad in the Orange Free State. Commercially available computer based packages were used for the development and simulation of both the mathematical model and fluid flow. During the flow simulations, an actual Zebra conductor and Zebra bundle configuration were utilised. For the development of the mathematical model, the pratical results, as measured at the Kroonstad transmission line test station during Phase I, were utilised. From the tests performed during Phase I, it was concluded that the damping solutions, currently used by Eskom as tested during Phase I, are all effective in controlling the aeolian vibration. The Stockbridge damper proved to be avery effective damper. Two models for the prediction of aeolian vibration levels were derived. Results showed that the vibration levels could be estimated to the correct order of magnitude and in many cases the precise values. The accuracy of the model was further improved by the inclusion of the Strouhal number as a function of windspeed. It has been decided by the author 10 develop and design a low cost vibration activity indicator for aeolian vibration measurements. The T-R-I-V-A-I has shown that it is a repeatable, reliable device, Ideally suited for line vibration detection. A new device, the W-I-V-I, has also been designed and implemented by the author for the detection and quantification of wake-induced vibration. During the simulation of the flows around a conductor in the steady state, it was established that the flow around as smooth cylinder and a Zebra conductor, is very similar, however, it was established that the rough outer surface of the Zebra conductor acts as a vortex generator. It has been found that a stability relationship exists between the degree of symmetry of the pressure cell, directly in front of the leeward conductor and the wake-induced vibration. Results for the unsteady flow situation showed the initiation and dispersion of the vortices as they are generated alongside the conductor. It is recommended that the developed model's accuracy be further enhanced. It should be established if .there are families of curves and data that belong together and that contribute to the amount of scatter in the parameters measured such as vibration amplitude, Strouhal number, etc. The applicability of CFD to the transmission line field should be enhanced, with the view of increasing bundle performance, both from an electrical and mechanical point of view.
- Full Text:
- Authors: Du Plessis, Pieter
- Date: 2014-05-08
- Subjects: Overhead electric lines , Telecommunication lines
- Type: Thesis
- Identifier: uj:10966 , http://hdl.handle.net/10210/10539
- Description: D.Ing. (Mechanical Engineering) , This research proposed to develop a mathematical model for the prediction of aeolian vibration levels on overhead transmission lines in order to be able to ensure that damping systems are designed optimally in future. In order to enhance the understanding of aeolian and wake-induced vibration further, it also proposed to implement and apply the fluid flow simulation technique of Computational Fluid Dynamics (CFD) to both single conductors and conductor bundles. The Introduction of the CFD tool to the field of transmission line vibration, will ensure that bundles could be optimally designed for future applications. Wind-induced vibrations are known to cause expensive damage to the conductors and related hardware through fatigue or clashing of the bundled conductors. The primary cause of conductor aeolian vibration is the alternate shedding of wind-induced eddies from the top and bottom sides of the conductor, whereas wake-induced oscillations is peculiar to bundled conductors and arises from effects of the shielding of leeward conductors in bundles by windward ones. In order to study the phenomenon of aeolian vibration, research was undertaken utilising a full scale transmission line test station close to Kroonstad in the Orange Free State. Commercially available computer based packages were used for the development and simulation of both the mathematical model and fluid flow. During the flow simulations, an actual Zebra conductor and Zebra bundle configuration were utilised. For the development of the mathematical model, the pratical results, as measured at the Kroonstad transmission line test station during Phase I, were utilised. From the tests performed during Phase I, it was concluded that the damping solutions, currently used by Eskom as tested during Phase I, are all effective in controlling the aeolian vibration. The Stockbridge damper proved to be avery effective damper. Two models for the prediction of aeolian vibration levels were derived. Results showed that the vibration levels could be estimated to the correct order of magnitude and in many cases the precise values. The accuracy of the model was further improved by the inclusion of the Strouhal number as a function of windspeed. It has been decided by the author 10 develop and design a low cost vibration activity indicator for aeolian vibration measurements. The T-R-I-V-A-I has shown that it is a repeatable, reliable device, Ideally suited for line vibration detection. A new device, the W-I-V-I, has also been designed and implemented by the author for the detection and quantification of wake-induced vibration. During the simulation of the flows around a conductor in the steady state, it was established that the flow around as smooth cylinder and a Zebra conductor, is very similar, however, it was established that the rough outer surface of the Zebra conductor acts as a vortex generator. It has been found that a stability relationship exists between the degree of symmetry of the pressure cell, directly in front of the leeward conductor and the wake-induced vibration. Results for the unsteady flow situation showed the initiation and dispersion of the vortices as they are generated alongside the conductor. It is recommended that the developed model's accuracy be further enhanced. It should be established if .there are families of curves and data that belong together and that contribute to the amount of scatter in the parameters measured such as vibration amplitude, Strouhal number, etc. The applicability of CFD to the transmission line field should be enhanced, with the view of increasing bundle performance, both from an electrical and mechanical point of view.
- Full Text:
The analysis and design of large centrifugal pump inlets
- Authors: Van Tonder, Reynier
- Date: 2014-02-20
- Subjects: Centrifugal pumps
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/377037 , uj:4190 , http://hdl.handle.net/10210/9537
- Description: M.Ing. (Mechanical Engineering) , Please refer to full text to view abstract
- Full Text:
- Authors: Van Tonder, Reynier
- Date: 2014-02-20
- Subjects: Centrifugal pumps
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/377037 , uj:4190 , http://hdl.handle.net/10210/9537
- Description: M.Ing. (Mechanical Engineering) , Please refer to full text to view abstract
- Full Text:
Ondersoek na instandhoudingsinligtingstelsels in 'n petrochemiese bedryf
- Van Niekerk, Johannes Albertus
- Authors: Van Niekerk, Johannes Albertus
- Date: 2014-02-18
- Subjects: Industrial equipment - Maintenance and repair. , Plant maintenance , Information storage and retrieval systems. , Petroleum chemicals industry
- Type: Thesis
- Identifier: uj:4168 , http://hdl.handle.net/10210/9515
- Description: M.Ing. (Mechanical Engineering) , Considering the high cost of maintenance, effective maintenance management have the potential to contribute to the profit of a petrochemical business. The complexity of the maintenance domain in the petrochemical business demands the use of information systems for the management of maintenance. The availability of correct, easily interpretable information about maintenance can therefore contribute to the profit of a petrochemical business. Management decisions are based on available information. The quality (accuracy and timeliness) of the information create more room for creative decisions in the maintenance department. A computerized information management system is a tool employed in the optimization of maintenance cost and a requirement for world class maintenance. This system depends on information of a high quality. It should be kept in mind that this systems is an aid to maintenance management and would never be able to replace the maintenance manager. The role played by high quality information in the success of a computerized maintenance management system point towards the importance of the personnel that maintain the system and those that provide input to the system. These personnel need to be highlytrained and should have the most recent technology available. Continuing development of the computerized maintenance management system within a company is necessary for the system to succeed.
- Full Text:
- Authors: Van Niekerk, Johannes Albertus
- Date: 2014-02-18
- Subjects: Industrial equipment - Maintenance and repair. , Plant maintenance , Information storage and retrieval systems. , Petroleum chemicals industry
- Type: Thesis
- Identifier: uj:4168 , http://hdl.handle.net/10210/9515
- Description: M.Ing. (Mechanical Engineering) , Considering the high cost of maintenance, effective maintenance management have the potential to contribute to the profit of a petrochemical business. The complexity of the maintenance domain in the petrochemical business demands the use of information systems for the management of maintenance. The availability of correct, easily interpretable information about maintenance can therefore contribute to the profit of a petrochemical business. Management decisions are based on available information. The quality (accuracy and timeliness) of the information create more room for creative decisions in the maintenance department. A computerized information management system is a tool employed in the optimization of maintenance cost and a requirement for world class maintenance. This system depends on information of a high quality. It should be kept in mind that this systems is an aid to maintenance management and would never be able to replace the maintenance manager. The role played by high quality information in the success of a computerized maintenance management system point towards the importance of the personnel that maintain the system and those that provide input to the system. These personnel need to be highlytrained and should have the most recent technology available. Continuing development of the computerized maintenance management system within a company is necessary for the system to succeed.
- Full Text:
Ondersoek na dinamiese effekte in brandstofleidings
- Authors: Piek, Linda
- Date: 2014-02-13
- Subjects: Pipe - Fluid dynamics , Pipe - Design and construction
- Type: Thesis
- Identifier: uj:3961 , http://hdl.handle.net/10210/9320
- Description: M.Ing. (Mechanical Engineering) , Please refer to full text to view abstract
- Full Text:
- Authors: Piek, Linda
- Date: 2014-02-13
- Subjects: Pipe - Fluid dynamics , Pipe - Design and construction
- Type: Thesis
- Identifier: uj:3961 , http://hdl.handle.net/10210/9320
- Description: M.Ing. (Mechanical Engineering) , Please refer to full text to view abstract
- Full Text:
A methodology for benchmarking in an engineering business environment
- Authors: Lindemann, Werner Philip
- Date: 2014-02-12
- Subjects: Engineering - Management , Benchmarking (Management)
- Type: Thesis
- Identifier: uj:3922 , http://hdl.handle.net/10210/9285
- Description: M.Ing. (Engineering Management) , Most new generation organisations have management models and organisational performance measurement systems in place. All these new kinds of models and systems will not be enough in the race for survival. Organisations needs a clear point of view of where they are going -a vision about tomorrow and what they should do to overcome the gap, from their current situation in order to get there successfully. It is also important for organisations to have a solid foundation to base such a visioning process on. Reengineering, continuous renewal, total quality management, lean production, downsizing - these all have proven vital to survival. But getting better at what we do is just about keeping ourselves in the race - it's not about winning the race. To win, we will have to know what the strategic intent and business priorities of the competition are (where are they going), in order to make sure we get there first. Charles Handy said about the winners of the race, "... it will be those who invent the world, not those who respond to it." Benchmarking is a means to ensure the above, where one basically have to say, "Let's look honestly at ourselves and determine what we do well and what we do badly. And where we do things badly, let's figure out what the world standards are, and then find some way to commit ourselves to reaching those standards." The purpose of this study was therefore to ensure a means for an organisation to get ahead in the race. It is important to note that performance measurement plays an integral role in management and benchmarking, because no process or action can be managed if it can be measured. Organisations are also not solely based on actual detail processes. There are other more strategic as well as "softer" issues of an organisation that will become much more important in the future, than concrete processes. These factors are the visioning processes within an organisation and their impact on change, as well as the creation and mobilisation of certain knowledge for certain purposes. The end-result of the study was therefore a scientific analysis of an engineering business environment, in order to create a means/methodology to do benchmarking, whilst ensuring a balance between the strategic, operational and knowledge aspects.
- Full Text:
- Authors: Lindemann, Werner Philip
- Date: 2014-02-12
- Subjects: Engineering - Management , Benchmarking (Management)
- Type: Thesis
- Identifier: uj:3922 , http://hdl.handle.net/10210/9285
- Description: M.Ing. (Engineering Management) , Most new generation organisations have management models and organisational performance measurement systems in place. All these new kinds of models and systems will not be enough in the race for survival. Organisations needs a clear point of view of where they are going -a vision about tomorrow and what they should do to overcome the gap, from their current situation in order to get there successfully. It is also important for organisations to have a solid foundation to base such a visioning process on. Reengineering, continuous renewal, total quality management, lean production, downsizing - these all have proven vital to survival. But getting better at what we do is just about keeping ourselves in the race - it's not about winning the race. To win, we will have to know what the strategic intent and business priorities of the competition are (where are they going), in order to make sure we get there first. Charles Handy said about the winners of the race, "... it will be those who invent the world, not those who respond to it." Benchmarking is a means to ensure the above, where one basically have to say, "Let's look honestly at ourselves and determine what we do well and what we do badly. And where we do things badly, let's figure out what the world standards are, and then find some way to commit ourselves to reaching those standards." The purpose of this study was therefore to ensure a means for an organisation to get ahead in the race. It is important to note that performance measurement plays an integral role in management and benchmarking, because no process or action can be managed if it can be measured. Organisations are also not solely based on actual detail processes. There are other more strategic as well as "softer" issues of an organisation that will become much more important in the future, than concrete processes. These factors are the visioning processes within an organisation and their impact on change, as well as the creation and mobilisation of certain knowledge for certain purposes. The end-result of the study was therefore a scientific analysis of an engineering business environment, in order to create a means/methodology to do benchmarking, whilst ensuring a balance between the strategic, operational and knowledge aspects.
- Full Text:
An assessment of customer satisfaction management practices
- Authors: Shao, Ziqiong
- Date: 2014-02-12
- Subjects: Consumer satisfaction - Evaluation , Consumer Satisfaction , Consumer Satisfaction - Management , Consumer Satisfaction - Japan - Management
- Type: Thesis
- Identifier: uj:3923 , http://hdl.handle.net/10210/9286
- Description: M.Phil. (Engineering Management) , For over a decade, customer satisfaction has received increasing attention in marketing. Customer satisfaction is related to loyalty, which in tum is linked to increased profitability, market share, growth, and decreased costs.8 During the 1980s, Japanese firms won major market shares with their product quality and speed. As most leading western companies caught up with their Japanese competitors on quality, most Japanese firms were focusing on a new strategy to meet and exceed changing customer expectations in the 1990s.1 To produce loyalty to an organization became one of the most popular marketing trends of the last decade.1·32 However, customers remain loyal only as long as they are completely satisfied with the quality of the service or product provided? Research results show that it costs five to seven times more to recruit a new customer than it does to retain one." Numerous research studies have shown that the average customer who is happy with a product and a service tells at least three people of his satisfaction, while a dissatisfied customer tells 9 or 10 people about his dissatisfactionf Knowledge of customers' perceptions and attitudes about an organization's business will greatly enhance its opportunity to make better business decisions." More than 80 percent of innovations in high-performing companies come from customers' ideas.'
- Full Text:
- Authors: Shao, Ziqiong
- Date: 2014-02-12
- Subjects: Consumer satisfaction - Evaluation , Consumer Satisfaction , Consumer Satisfaction - Management , Consumer Satisfaction - Japan - Management
- Type: Thesis
- Identifier: uj:3923 , http://hdl.handle.net/10210/9286
- Description: M.Phil. (Engineering Management) , For over a decade, customer satisfaction has received increasing attention in marketing. Customer satisfaction is related to loyalty, which in tum is linked to increased profitability, market share, growth, and decreased costs.8 During the 1980s, Japanese firms won major market shares with their product quality and speed. As most leading western companies caught up with their Japanese competitors on quality, most Japanese firms were focusing on a new strategy to meet and exceed changing customer expectations in the 1990s.1 To produce loyalty to an organization became one of the most popular marketing trends of the last decade.1·32 However, customers remain loyal only as long as they are completely satisfied with the quality of the service or product provided? Research results show that it costs five to seven times more to recruit a new customer than it does to retain one." Numerous research studies have shown that the average customer who is happy with a product and a service tells at least three people of his satisfaction, while a dissatisfied customer tells 9 or 10 people about his dissatisfactionf Knowledge of customers' perceptions and attitudes about an organization's business will greatly enhance its opportunity to make better business decisions." More than 80 percent of innovations in high-performing companies come from customers' ideas.'
- Full Text:
Maintenance management with emphasis on condition monitoring of excavation machines
- Authors: Gouws, Leonie Elizabeth
- Date: 2014-02-12
- Subjects: Earthmoving machinery - Maintenance and repair
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/369566 , uj:3924 , http://hdl.handle.net/10210/9287
- Description: M.Ing. (Engineering Management) , Please refer to full text to view abstract
- Full Text:
- Authors: Gouws, Leonie Elizabeth
- Date: 2014-02-12
- Subjects: Earthmoving machinery - Maintenance and repair
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/369566 , uj:3924 , http://hdl.handle.net/10210/9287
- Description: M.Ing. (Engineering Management) , Please refer to full text to view abstract
- Full Text:
Transoniese saamdrukbare vloeiontleding in 'n klein 5N hidrasien stuwer.
- Authors: Henning, Barend Jacobus
- Date: 2014-02-11
- Subjects: Power electronics. , Space vehicles. , Actuators.
- Type: Thesis
- Identifier: uj:3850 , http://hdl.handle.net/10210/9219
- Description: M.Ing. (Mechanical Engineering) , Please refer to full text to view abstract
- Full Text:
- Authors: Henning, Barend Jacobus
- Date: 2014-02-11
- Subjects: Power electronics. , Space vehicles. , Actuators.
- Type: Thesis
- Identifier: uj:3850 , http://hdl.handle.net/10210/9219
- Description: M.Ing. (Mechanical Engineering) , Please refer to full text to view abstract
- Full Text:
Ortotropiese swigtingskriteria vir hout
- Authors: Haasbroek, Daniel Francois
- Date: 2014-02-10
- Subjects: Wood - Testing
- Type: Thesis
- Identifier: uj:3707 , http://hdl.handle.net/10210/9089
- Description: M.Ing. , Timber is an organic, orthotropic material of which the strength is currently not fully utilised in structural designs. Most design codes treat timber as an isotropic material with special clauses to compensate for the weaker strength across the grain. Several safety factors are used to accommodate the large variations in the strength of timber. In the orthotropic approach presented here, the unidirectional properties of timber are assumed as constant. It is also assumed that the large strength variation which is observed between samples of the same group, can mostly be attributed to the grain slope variation in a sample. The finite element method is employed to model grain slopes around a predetermined defect in a sample. The sample is then forced to fail at this defect, and the finite element model is then analyzed at the failure load to determine which stress combination led to the failure. Initial unidirectional material strengths are used in a failure criterion to evaluate the critical stress combination. The method of least squares is used to fit the predicted strength against the experimental strength. In this process new values are found for the unidirectional material strengths. The process is then repeated to determine whether another stress combination is not more critical than the original choice. As soon as the numerically acquired material strengths stabilise, it is compared with known values. The results indicate that the strength of a timber section can be predicted on the grounds of the observed fibre directions if the unidirectional material strengths are known.
- Full Text:
- Authors: Haasbroek, Daniel Francois
- Date: 2014-02-10
- Subjects: Wood - Testing
- Type: Thesis
- Identifier: uj:3707 , http://hdl.handle.net/10210/9089
- Description: M.Ing. , Timber is an organic, orthotropic material of which the strength is currently not fully utilised in structural designs. Most design codes treat timber as an isotropic material with special clauses to compensate for the weaker strength across the grain. Several safety factors are used to accommodate the large variations in the strength of timber. In the orthotropic approach presented here, the unidirectional properties of timber are assumed as constant. It is also assumed that the large strength variation which is observed between samples of the same group, can mostly be attributed to the grain slope variation in a sample. The finite element method is employed to model grain slopes around a predetermined defect in a sample. The sample is then forced to fail at this defect, and the finite element model is then analyzed at the failure load to determine which stress combination led to the failure. Initial unidirectional material strengths are used in a failure criterion to evaluate the critical stress combination. The method of least squares is used to fit the predicted strength against the experimental strength. In this process new values are found for the unidirectional material strengths. The process is then repeated to determine whether another stress combination is not more critical than the original choice. As soon as the numerically acquired material strengths stabilise, it is compared with known values. The results indicate that the strength of a timber section can be predicted on the grounds of the observed fibre directions if the unidirectional material strengths are known.
- Full Text: