A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering. / The project report deals with the relationship between the undrained shear strength and the moisture content of Red Berea sand tailings. The tailings were obtained from the Red Berea sand dunes near Richards Bay, Kwa-Zulu Natal, South Africa. The geology of the area consists of Miocene deposits of red clayey sand, classified as Berea Formation. A method for determining stability of a tailings dam for Red Berea sand tailings, was investigated. The general method of using the degree of saturation of the tailings to specify the rate of rise, is not applicable to this type of tailings. It was found that a relationship exists between the undrained shear strength of the tailings, and the moisture content. The moisture content can easily be measured and the undrained shear strength can then be calculated. The calculated undrained shear strength can be used in a total stress analysis to determine a factor of safety against failure. This project report consists of a discussion of the literature, which was used as the basis for the assumptions made, as well as a description of the tests performed to prove the above-mentioned relationship. Test results are given, interpreted and used in an illustrative example of a stability analysis. / Andrew Chakane 2020

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The aim of this study is to identify and explicate Nietzsche’s standard of value, that is, the basis upon which he approves of some human phenomena (e.g., moralities, philosophies, artistic and political movements, etc.) and disapproves of others. I argue that this standard is best captured by the concept of “degrees of strength.” Part I undertakes a detailed examination of Nietzsche’s philosophical methodology, which must be understood in order to understand his conception of degrees of strength. I argue that the central tenet of his methodology is his commitment to “historical philosophy,” that is, to the view that absolutely opposite phenomena like soul and body, good and evil, and so on, do not exist as opposites, and that their opposition is only relative. I here engage with what is perhaps the most prominent reading of Nietzsche’s methodology in the Anglophone world today, namely that it is a form of “naturalism,” understood as a commitment to some kind of continuity with the empirical sciences. I show that this reading relies on a definition of “nature” that Nietzsche never gives, and commits him to an ontology that he explicitly rejects, without doing anything to clarify his methodology that is not done by the concept of historical philosophy. Part II examines Nietzsche’s attempt to formulate a “proper physio-psychology” based on historical philosophy, which requires him to conceive of human beings as communities of willing subjects that he calls “drives.” I argue that Nietzsche adopts the notion of the human being as a multiplicity from physiology, and attempts to combine it with the notion of the willing subject that arises from introspective psychology. He believes that the human belief in causality is a result of the psychological experience of willing, and that physiology cannot explain the causal relations among events in the body without appealing to a concept of will. I then show how he extends this insight beyond the body to the world as a whole, arguing that we cannot comprehend causality at all except by means of the concept of “will to power.” This, I claim, is Nietzsche’s main reason for asserting that the world is “will to power and nothing else.” Part III introduces Nietzsche’s concept of the “problem of value,” the solution of which amounts to what he calls “the determination of the order of rank among values,” that is, of which human values contribute most to the enhancement of the power of humanity, and which frustrate such enhancement. I argue that the standard by which Nietzsche determines this is a symptomatology based on the concept of degrees of strength: those “ways of thinking and valuing” that are symptomatic of higher degrees of physio-psychological strength are more valuable for the enhancement of the overall power of humanity, while those that are symptomatic of weakness are less valuable, or even disvaluable, for that end. While the main focus of Part III is to explicate the concepts of physio-psychological strength and weakness, I conclude with an examination of what Nietzsche calls the “great economy of the whole,” according to which even weakness often has value for enhancing the power of humanity, so long as it is kept in its proper place and not valued more highly than strength. / Dissertation / Doctor of Philosophy (PhD)

The purpose of the study was to determine anthropometric characteristics that may affect deadlift performance. Fourteen powerlifters performed isometric pulls on a force plate at 3 key positions of the deadlift (at the floor, just above the patella, and 5-6 cm short of lockout) and the mid-thigh pull (MTP). RM ANOVA revealed that forces generated at each bar height differed significantly (F(3,39) = 51.058, p<0.05). Discriminant analysis was able to classify lifters into "stronger" and "weaker" groups with 100% accuracy using measured anthropometric dimensions. Stepwise discriminant analysis revealed that height to body mass ratio was important in differentiating performance in all positions but lockout. Segment and various measures of height were also important in discriminating performance in the knee, lockout, and MTP positions. Results of this analysis should provide some insight to the anthropometric dimensions that are related to success in various phases of the deadlift.

Clay, quartz and feldspar are widely available in Uganda. The location and properties of various clay deposits are reported in the literature, but little is reported on feldspar and quartz deposits. In this work an extended literature on ceramics and porcelains in particular, is documented. Samples from two deposits of feldspar and two deposits of quartz are characterised and found to possess requisite properties for making porcelain insulators. Sample porcelain bodies are made from materials collected from selected deposits using different mixing proportions of clay, feldspar and quartz. Their properties in relation to workability, firing temperature, dielectric and bending strengths are studied. It is found that a mixture consisting of 30% Mutaka kaolin, 15% Mukono ball clay, 30% Mutaka feldspar and 25% Lido beach flint yields a body with highest mechanical strength (72MPa) and dielectric strength (19kV/mm) when fired at 1250°C. The strength (both mechanical and dielectric) is found to decrease with increasing firing temperature. At high firing temperatures, the undissolved quartz in the body decreased, the glass content increases and pores are formed. Mullite content on the other hand does not change at temperatures above 1200°C but there are significant differences in the morphologies of the mullite crystals in the samples. Optimum mechanical and electrical properties are found at maximum virtification and a microstructure showing small closely packed mullite needles. / QC 20101122

Some controversy exists as to the most efficacious method of training to achieve enhanced levels of sport performance. Controversy concerning the efficacy of periodization and especially block periodization (BP) likely stems from the use of poorly or untrained subjects versus trained who may differ in their responses to a stimulus. The purpose of this study was to investigate the effect of training status on performance outcomes resulting from 11 weeks of BP training. Fifteen males were recruited for this study and placed into strong (age = 24.3 ± 1.9 years., body mass (BM) = 87.7 ± 8.7 kg, squat: body mass = 1.96 ± 0.16), moderate (age = 25.3 ± 2.7 years., body mass = 100.2 ± 15.5 kg, squat: body mass = 1.46 ± 0.14), or weak (age = 23.2 ± 3.9 yrs., body mass = 83.5 ± 17.1 kg, squat: body mass = 1.17 ± 0.07) groups based on relative strength. Testing was completed at baseline, and after each block which consisted of 1 repetition maximum (1RM) squat, 0 kg static jump (SJ), 0 kg countermovement jump (CMJ), 20 kg SJ, and 20 kg CMJ. Absolute and relative strength were strongly correlated with rates of improvement for absolute strength, relative strength, 0 kg, and 20 kg vertical jumps. All subjects substantially improved back squat ( < 0.001), relative back squat ( < 0.001) with large-very large effect sizes between groups for percent change favoring the weak group over the moderate and strong group for all performance variables. All subjects showed statistically significant improvements in 0 kg SJ ( < 0.001), 0 kg CMJ ( < 0.001), 20 kg SJ ( = 0.002), and 20 kg CMJ ( < 0.001). Statistically significant between group differences were noted for both 20 kg SJ ( = 0.01) and 20 kg CMJ ( = 0.043) with the strong group statistically greater jump heights than the weak group. The results of this study indicate BP training is effective in improving strength and explosive ability. Additionally, training status may substantially alter the response to a resistance training program.

When a clay soil is sheared, clay particles along the shear plane become aligned in the direction of shear, forming "slickensided" surfaces. Slickensided surfaces are often observed along the sliding plane in field landslides. Because the clay particles along a slickensided surface are already aligned in the direction of shear, the available shear resistance is significantly less than that of the surrounding soil. During an earthquake, ground shaking often causes landslide movement. For existing landslides or repaired landslides that contain slickensided rupture surfaces, it is reasonable to expect that the movement will occur along the existing slickensided surfaces, because they are weaker than the surrounding soil. The amount of movement that occurs is controlled by the dynamic resistance that can be mobilized along the slickensided surfaces. The objective of this study was to investigate, through laboratory strength tests and centrifuge model tests, the shearing resistance that can be mobilized on slickensided rupture surfaces in clay slopes during earthquakes. A method was developed for preparing slickensided rupture surfaces in the laboratory, and a series of ring shear tests, direct shear tests, and triaxial tests was conducted to study the static and cyclic shear resistance of slickensided surfaces. Two dynamic centrifuge tests were also performed to study the dynamic shear behavior of slickensided clay slopes. Newmark's method was used to back-calculate cyclic strengths from the centrifuge data. Test results show that the cyclic shear resistance that can be mobilized along slickensided surfaces is higher than the drained shear resistance that is applicable for static loading conditions. These results, coupled with a review of existing literature, provide justification for using cyclic strengths that are at least 20% larger than the drained residual shear strength for analyses of seismic stability of slickensided clay slopes. This represents a departure from the current state of practice, which is to use the drained residual shear strength as a "first-order approximation of the residual strength friction angle under undrained and rapid loading conditions" (Blake et al., 2002). / Ph. D.

Simplified mechanical loading paths, which represent more complex loading paths observed during penetration, were investigated using a triaxial chamber and a high-strength concrete. Objectives were to determine the effects that stress/strain (load) paths had on the material’s unconfined (UC) residual strength. The loading paths included hydrostatic compression (HC), uniaxial strain in compression (UX), and uniaxial strain load biaxial strain unload (UXBX). The experiments indicate that load paths associated with non-visible microstructural damage were HC and UX, which produced minimal impact on the residual UC strength (<30%), while the load paths associated with visible macro-structural damage were UXBX, which significantly reduced the UC strength (>90%). The simplified loading paths were also investigated using a material model driver code that was fit to a widely used Department of Defense material model. Virtual experiment data revealed that the material model investigated overestimated material damage and produced poor results when compared to experimental data.

This study is an investigation into methods of developing ergonomic guidelines for automotive assembly tasks involving insertion of small parts. The study was conducted in four major parts: 1) a method of determining and evaluating subjective exertion limits was modified and tested, 2) a large dataset was collected from an industrial population in 10 simulated assembly line tasks, 3) a smaller dataset was collected from a student population to assess hand dominance effects, and 4) strength data obtained was compared with a strength prediction model to determine if the model could predict manual insertion forces. The traditional method of psychophysical data collection requires participants to extrapolate sensations from a relativity short session to judge if the task could be done for a much longer period. Maximum acceptable limits (MALs) are typically derived from having participants adjust a weight, resistance, or frequency to an acceptable level. The present study evaluated a relatively new method of collecting MAL data for simple, single-digit exertions where participants were asked to determine an MAL by self-adjusting and then regulating to maintain the exertion level. Results showed that MAL values obtained from a series of self-regulated exertions were independent of both analysis method and duration (5 minutes vs. 25 minutes) used for evaluation, and that the method was repeatable both within and between sessions. Ergonomic guidelines are often obtained from the strength capacity for a certain task, as it is important to ensure that workers possess sufficient strength to accomplish a task. As task demands increase, however, a larger percentage of a worker's strength capability in required, and other factors, such as performance and worker comfort, tend to be compromised. In this work, both strength capacity and subjective limits were obtained for a variety of simulated tasks to facilitate development of guidelines for the specific tasks. The relationship between these two measures (maximum force, acceptable force) was determined, and acceptable limits were found to be approximately 55% of population strength capacity, with correlations (R2) ranging from 0.40 to 0.60 depending on the task, suggesting the subjective limits and strength capacity are related in these tasks. Hand dominance was found to have a small (5%), but significant (p = 0.006) effect on strength capability, and no significant effect on subjective limit. Biomechanical strength prediction models can be used to assess loads placed on the human performing various tasks. One of the more popular models, Three-Dimensional Static Strength Prediction Program, is often used for heavy material handling tasks, such as lifting or pushing. The tasks studied presently, however, are manual insertions, requiring localized force application rather than whole body exertion. The prediction capabilities of this strength prediction model were compared with strength values obtained from the simulated assembly tasks. Results indicated that the model was not successful when predicting localized force, accounting for only 40% of the observed variance in strength (R2 = 0.4) / Master of Science

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