Deep level mining is widely practised throughout South Africa, particularly in the gold sector, where the extraordinary depths of vertical hoisting present an array of challenges. The accurate and secure positioning of a conveyance next to a station has been and continues to be one of the unresolved challenges that have led to many serious injuries and equipment damage. The literature study presented in this dissertation highlights some of the complexities associated with properly docking a conveyance and investigates some current, proposed and similar systems to address the issue. From the study it was found that no satisfactory device existed prompting a systematic design of a conveyance arresting device capable of securing a conveyance in a vertical shaft at any level. Proper definition of the system requirements was obtained and summarised into 16 groups. The system requirements play an important role in the design process by setting the direction but also featuring in concept screening and evaluation. In order to generate concepts a variety of creativity inspiring techniques were employed facilitating a systematic search for a solution. Application of the techniques, Brainstorming, Synectics, TRIZ, 2500 Engineering Principles, Sourcebooks and a Morphological chart resulted in the synthesis of 9 concepts. Screening and evaluation was performed on these concepts and the most suitable concept identified. The proposed concept is a simple system where two sets of beams are extended into the shaft in order to have the conveyance settle onto the supporting shaft steelwork. Once the conveyance came to a rest on the steelwork a second set of beams are extended beneath the steelwork to positively lock the conveyance in position. This required the geometric design of the system to ensure adequate strength to satisfy a factor of safety of ten. Design decisions were made on the section properties of the clamp beam by comparing a solid section and a box section. A supporting frame is used to guide the beams, with consideration given to the most appropriate method of attaching this support frame to the conveyance. The first choice was to have the beams extend from the rear of the conveyance but due to the moments and forces involved the conveyance roof structure could not support this configuration. The support frame was instead affixed directly to the conveyance Transom. In order to support the findings of the conventional calculations performed on the system components the system was subjected to finite element analysis. The results obtained from the simulation corresponded well for the simple components and varied somewhat in the more complex shapes attributed to the assumptions made to ease the conventional calculations. Weight and reliability in a harsh shaft environment was identified as critical design parameters and motivated the use of exotic high strength materials. The high strength of the materials made is possible to design a system with practical dimensions of adequate strength supported by the conventional and modelled calculations. Even though high strength materials were used in the design the overall system weigh is dissatisfying. A potentially successful and practical device was designed but certain factors such as weight, cost, conveyance structure and infrastructure modifications threaten the implementation of the design. This dissertation sets a sound foundation for future development and the continued search for a practical simple solution to this age old challenge. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

Deep level mining is widely practised throughout South Africa, particularly in the gold sector, where the extraordinary depths of vertical hoisting present an array of challenges. The accurate and secure positioning of a conveyance next to a station has been and continues to be one of the unresolved challenges that have led to many serious injuries and equipment damage. The literature study presented in this dissertation highlights some of the complexities associated with properly docking a conveyance and investigates some current, proposed and similar systems to address the issue. From the study it was found that no satisfactory device existed prompting a systematic design of a conveyance arresting device capable of securing a conveyance in a vertical shaft at any level. Proper definition of the system requirements was obtained and summarised into 16 groups. The system requirements play an important role in the design process by setting the direction but also featuring in concept screening and evaluation. In order to generate concepts a variety of creativity inspiring techniques were employed facilitating a systematic search for a solution. Application of the techniques, Brainstorming, Synectics, TRIZ, 2500 Engineering Principles, Sourcebooks and a Morphological chart resulted in the synthesis of 9 concepts. Screening and evaluation was performed on these concepts and the most suitable concept identified. The proposed concept is a simple system where two sets of beams are extended into the shaft in order to have the conveyance settle onto the supporting shaft steelwork. Once the conveyance came to a rest on the steelwork a second set of beams are extended beneath the steelwork to positively lock the conveyance in position. This required the geometric design of the system to ensure adequate strength to satisfy a factor of safety of ten. Design decisions were made on the section properties of the clamp beam by comparing a solid section and a box section. A supporting frame is used to guide the beams, with consideration given to the most appropriate method of attaching this support frame to the conveyance. The first choice was to have the beams extend from the rear of the conveyance but due to the moments and forces involved the conveyance roof structure could not support this configuration. The support frame was instead affixed directly to the conveyance Transom. In order to support the findings of the conventional calculations performed on the system components the system was subjected to finite element analysis. The results obtained from the simulation corresponded well for the simple components and varied somewhat in the more complex shapes attributed to the assumptions made to ease the conventional calculations. Weight and reliability in a harsh shaft environment was identified as critical design parameters and motivated the use of exotic high strength materials. The high strength of the materials made is possible to design a system with practical dimensions of adequate strength supported by the conventional and modelled calculations. Even though high strength materials were used in the design the overall system weigh is dissatisfying. A potentially successful and practical device was designed but certain factors such as weight, cost, conveyance structure and infrastructure modifications threaten the implementation of the design. This dissertation sets a sound foundation for future development and the continued search for a practical simple solution to this age old challenge. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

Student Number :0008015M - MSc Dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / Shaft voltages and currents are an unavoidable characteristic of rotating machines, though they are typically a nuisance this work shows that shaft signals can be used for fault diagnosis. This work focussed on shaft voltages present on synchronous generators. Measurements on a 4-pole generator found that the angular position of the shaft could be determined from the shaft voltage. An experimental 20 kVA 2-pole synchronous generator was designed and built which resembled a full-size 600 MVA turbo-generator. The effects of a static eccentricity on the shaft voltage were successfully determined firstly through FEM simulation and then verified with physical measurements. Shaft voltages can be used to diagnose static eccentricity, future work should investigate other faults. In addition, computer simulation was found to be effective and simulation and measurements of operating machines (such as turbo-generators) should be considered.

Detta examensarbete behandlar analys, simulering och dimensionering en drivaxel till en baltransportör för returfiber vid SCA Munksund. Transportören drivs i dagsläget av två hydraulmotorer försedda med varsin 3-stegs planetväxellåda, en på varje sida av drivaxeln för transportbandet. Växellådorna skall bytas ut och en driftsäker, kostnadseffektiv ersättningslösning efterfrågas. I studien kartläggs dimensionerande belastningar och en belastningsmodell upprättas för kedjetransportören. Befintlig axel beräknas både analytiskt och simuleras i Solidworks Simulation. Axeln, inklusive monterade detaljer som rullager, kedjehjul och kilar utreds med avseende på hållfasthet i fyra lastfall: Enkeldrift och dubbeldrift, med nominell belastning respektive maximal belastning. Studien konstaterar att befintlig axel håller i nuvarande uppställning men bör inte modifieras för att passa en ny växellåda, stor risk för plasticering av axeln föreligger. Befintlig axel håller inte för enkeldrift, spänningar i axelns stål överskrider sträckgränsen i a xelförbandet mot v äxellådan och lagerläget för mittersta rullagret. Förslag på en ny axel har tagits fram. Beräkningsunderlag, simuleringar och tillverkningsritning redovisas. Den nya axeln tillverkas i SS2541 som har sträckgränsen 700 MPa och med förbättringar i hålkäler främst vid diameterändringar kan befintliga lagringar återanvändas. En kostnadsuppskattning bifogas för kostnader relaterade till axelbytet.

<p>The subject of this M.Sc. thesis is to find out whether the lime industry is a possible business area for Kanthal AB. The lime industry is one of the biggest chemical industries in the world and it is very energy demanding. In the process of making quicklime, calcium oxide, a lot of energy is needed as the dissociation of limestone, which consists mainly of calcium carbonate, takes place in the temperature span between 900°C and 1300°C. The total production of quicklime was in 2009 about 280 million tonnes, and the selling price was about $100 per ton. Today, all limekilns are driven by fossil fuels, i.e. oil, coal and gas. The increasing demand on lowering the emissions of carbon dioxide strongly affects the industry, as it is responsible for about 2 % of the total emissions of carbon dioxide. The industry itself claims that the emissions may only be reduced about 10 %, although at very high costs. Kanthal AB produces electric heating solutions that may be suitable for lime production. However, the lime industry is conservative and the use of electricity for lime production is not economically feasible today. Most of the electricity comes from coal power plants and therefore the use of electricity would not be more environmentally friendly in most countries. New limekilns, which are more environmentally friendly, are on the way. These kilns do not necessarily have to use fossil fuels, provides a purer end product and the emission of carbon dioxide is minimized. The size of the production is also much lower, but the end products might be used in more demanding areas, e.g. the pharmaceutical industry, and be sold at a higher price. It is this area Kanthal has to focus on if going to enter the lime industry at this point.</p>

The subject of this M.Sc. thesis is to find out whether the lime industry is a possible business area for Kanthal AB. The lime industry is one of the biggest chemical industries in the world and it is very energy demanding. In the process of making quicklime, calcium oxide, a lot of energy is needed as the dissociation of limestone, which consists mainly of calcium carbonate, takes place in the temperature span between 900°C and 1300°C. The total production of quicklime was in 2009 about 280 million tonnes, and the selling price was about $100 per ton. Today, all limekilns are driven by fossil fuels, i.e. oil, coal and gas. The increasing demand on lowering the emissions of carbon dioxide strongly affects the industry, as it is responsible for about 2 % of the total emissions of carbon dioxide. The industry itself claims that the emissions may only be reduced about 10 %, although at very high costs. Kanthal AB produces electric heating solutions that may be suitable for lime production. However, the lime industry is conservative and the use of electricity for lime production is not economically feasible today. Most of the electricity comes from coal power plants and therefore the use of electricity would not be more environmentally friendly in most countries. New limekilns, which are more environmentally friendly, are on the way. These kilns do not necessarily have to use fossil fuels, provides a purer end product and the emission of carbon dioxide is minimized. The size of the production is also much lower, but the end products might be used in more demanding areas, e.g. the pharmaceutical industry, and be sold at a higher price. It is this area Kanthal has to focus on if going to enter the lime industry at this point.

Induction motors are commonly used in numerous industrial applications. To maintain a reliable operation of the motor, it is important to identify the potential faults that may cause the motor to fail. Bearing failures are one of the main causes of motor breakdown. The causes of bearing damage have been studied in detail for a long time. In some cases, bearing failed due to the current passing through them. In this thesis, bearing currents in an inverter driven five-phase induction motor are studied and a new solution is proposed. First, theory of shaft voltage and bearing current are presented. The causes are identified and current solutions are discussed. Then, new switching patterns are proposed for the five-phase induction motor. The new schemes apply a modified algorithm for the space vector pulse-width-modulation (SVPWM). The system is simulated and the results of the new switching patterns are compared with the conventional switching pattern. Finally, the new schemes are experimentally tested using a digital signal processor (DSP) to drive the five-phase IGBT inverter. The experimental results verified that the new switching pattern could reduce shaft voltages and bearing current without affecting the performance.

Hsuehshan tunnel which included two bore and three ventilation shaft systems is the longest (12.9 km) freeway tunnel in Taiwan. 56 species volatile organic compounds (VOCs) were sampled in two different locations each bore and three emitted shafts to determine the emission factors (EFs). Each sampling day has three sampling period: morning (8:00-10:00), Noon (12:00-14:00) and afternoon 16:00-18:00). C2 species were analyzed by GC/FID and C3 − C12 species were analyzed by GC/MS. The composition in southern bore was expressed by alkanes (36.69% − 39.20%), aromatics (34.14% − 36.33%), alkenes (20.27% − 21.95%), Alkynes (3.35% − 4.11%) and Naphthenes (1.06% − 1.35%). Northern bore had the similar profile. Ethylene (4.93 ¡Ó 2.21 mg/veh-km), Isopropane (4.85 ¡Ó 2.75 mg/veh-km), toluene (4.55 ¡Ó 1.31 mg/veh-km), m,p-xylene (2.98 ¡Ó 0.90 mg/veh-km) and propylene (2.70 ¡Ó 0.88 mg/veh-km) are the top five abundant VOCs in southern bore ; Isopropane (6.78 ¡Ó 3.33 mg/veh-km), ethylene (5.44 ¡Ó 2.63 mg/veh-km), toluene (5.32 ¡Ó 2.39 mg/veh-km), propylene (3.55 ¡Ó 1.67 mg/veh-km) and m,p-xylene (3.36 ¡Ó 1.45 mg/veh-km) are the top five abundant VOCs in northern bore. The EFs were smaller than other freeway tunnel investigated. Shaft emitted the partial mass of VOCs result in concentration gradient dropped off. The total VOCs EF of shafts during holidays was in the range of 72.24 mg/s − 180.60 mg/s higher than on weekdays in the range of 53.40 mg/s − 82.74 mg/s. The EF of shafts had effected by air-extracting apparatus, so standard deviations (S.D.) varied widely. Combining the EF of shaft with EF of tunnel we obtained the overall vehicle EF which was close to other freeway tunnel results. The proportion of Ozone formation potential (OFP) in both bore were alkenes (47.5% − 48.5%), aromatics (40.2% − 42.3%) and alkanes (9.8% − 10.1%). Note that sum of alkenes and aromatics exceeded 90%.

The purpose of this study is the distribution, the emission factors, and the emission rates of the ventilation shafts of air pollutant concentration in the Hsuehshan tunnel, and analyze the correlation. The study, in the inside of Hsuehshan tunnel (the southern and the northern) and the three ventilation shafts, the real-world measure air pollutants(CO, NOx, NO, THC, NMHC and SO2) at the same time, and to analyze the concentration of air pollutants in the tunnel that is distribution of the time and spatial. In this study, the ventilation system is natural ventilation in the Hsuehshan tunnel, and the proportion of heavy vehicles in the period are less than 8%. The concentration of air pollutants in the tunnel, showing the exit higher than the entrance, the northern tunnel higher than the southern tunnel and the holidays higher than on weekdays concentration of distribution trends. The emissions and the concentration of air pollutants at the ventilation shaft No. 2 are the highest with the three shafts. All the ventilation shafts on holidays higher than weekdays were displayed on the trend of concentration distribution. The concentration of air pollutants in the tunnel are CO (12.04¡Ó1.85 ppm), THC (4.08¡Ó0.48 ppm), NMHC (2.21¡Ó0.46 ppm), NOx (1.58¡Ó0.23 ppm), NO (1.44¡Ó0.20 ppm) and SO2 (6.33¡Ó0.83 ppb). The results show that the emission factors of air pollutants in northern tunnel are higher than in southern tunnel by influence of slope. The emissions of ventilation shaft a sequence were CO, THC, and NOx. The concentrations(r¡×0.55 − 0.93) and the emission factors(r¡×0.60 − 0.96) of air pollutants are much related with traffic situation, and it shows that the air pollutants change with traffic condition. Comparison the emission factors between this study and past research in the Hsuehshan tunnel show that the air quality are becoming badly.

Estimating the earth pressures applied on drilled shaft retaining walls in expansive clays is challenging due to the soil's tendency to shrink and swell under cycles of moisture fluctuation. While empirical suggestions do exist, significant uncertainty exists regarding the effect of volumetric changes of the soil on the earth pressures. In order to investigate this uncertainty, a fully instrumented drilled shaft retaining wall named in the honor of Lymon C. Reese, was constructed in the highly expansive clay of the Taylor formation. Inclinometers and optical fiber strain gauges were installed in three instrumented shafts and time domain reflectrometry sensors were placed within the soil to measure changes in the moisture content. Nearly two years of monitoring data have been obtained which are used to estimate the earth pressure distribution at different moisture conditions. Processing of the raw strain data was required to eliminate the effects of tension cracks and other microscale factors that caused significant variation in the results. Good agreement was obtained between the processed strain and inclinometer data as the deflected shapes predicted from both monitoring elements were similar. Finally, the earth pressure distribution for six dates that represent different moisture conditions of the Taylor clay were plotted and the results of the strain gauge and inclinometer analysis were consistent. A p-y analysis was also conducted to estimate the range of earth pressures applied on the wall. A triangular earth pressure diagram was used as external load above the excavation level and the equivalent fluid pressure was evaluated by matching the deflected shapes generated from the inclinometer data to those predicted by the p-y model. The results were compared to the empirical values that TxDOT uses for design of similar type of walls in expansive clay. Finally, the side shear and temperature effects on the lateral response of the wall were quantified. A differential linear thermal model was used to evaluate the temperature effects and a t-z analysis was conducted to account for the side shear applied on the wall due to volumetric changes of the soil. It is recommended that their combined effect be considered in the design. / text