Master of Science / Food Science / Fadi Aramouni / Nutrition from whole grains has become an integral part of a healthy diet. Consumers are focused on adding fiber and whole grains to be healthy and want the benefits of whole grain with the taste and appearance of refined flour. A review of current commercial whole wheat flour in the marketplace indicated many options for food processors to use. However, many of these options required processing changes and added ingredients to provide the consumer with a quality product. A milling and baking study was done to compare commercially and experimentally milled whole wheat flours from both white and red wheat varieties. Both white and red wheat varieties were kept identity preserved. Experimental milling was done with a hammer mill and a roll stand to closely replicate the commercial milling process. Baking was done using a sponge and dough method to closely replicate commercial baking conditions. The results showed both particle size and wheat variety impact bake performance of whole wheat flour. The most significant impact appeared to be dependent on the variety of wheat being milled. The milling process also had an impact. As particle size decreased, bake functionality improved. However, some decreased functionality was seen when particle size became very fine. It was concluded that additional work on a commercial flour mill needed to be done to determine if an optimal particle size for milling whole wheat flour exists. Experimental milling equipment was not adequate enough to replicate particle size distributions of commercial whole wheat mills.

Master of Science / Department of Grain Science and Industry / Charles Stark / Experiments were conducted to evaluate particle size methodology and flow-ability of fractionated corn. The first experiment compared five variations of the current approved method to determine geometric mean diameter (d[subscript]gw) and geometric standard deviation (S[subscript]gw) described by ANSI/ASAE S319.4 “Method of determining and expressing fineness of feed materials by sieving”. This method controls many variables, including the suggested sample size and the type, number, and size of sieves. However, the method allows for variations in sieving time, sieve agitator inclusion, and the use of dispersing agent. The variations were tested with three grains (corn, wheat, and sorghum). There was no method × grain (P>0.05) interaction for d[subscript]gw, so it was removed. Ten minute sieving time with sieve agitators and dispersing agent resulted in the lowest d[subscript]gw and greatest S[subscript]gw (P<0.05). The second experiment evaluated particle size analysis on ground corn using a 3-sieve method with varying sieving time (30, 60, and 90 s) with the addition of dispersing agent. The sieving time for the 3-sieve method referred to the time sieves were hand shaken side to side. Ninety seconds sieving time with dispersing agent (0.25 g) resulted in the lowest d[subscript]gw (P<0.05). The 3-sieve method was not developed to calculate the S[subscript]gw, so means and main effects were not determined. Experiment three evaluated particle size and flow-ability by grinding corn at two moisture (10 and 12%) with three screenings levels (0, 2.5, and 5%). Results suggested cleaning corn prior to grinding with a roller mill does not change particle size or flow-ability. Experiment four continued the evaluation of flow-ability with corn ground to three target particle sizes (400, 500, and 600 µm) and fractionated into fine, medium, and coarse segments. Target particle size impacted d[subscript]gw, S[subscript]gw, and bulk density (P<0.05), prior to fractionation. Based on the results of this experiment, flow-ability can be improved if fine particles (<282 µm) are removed. Results of these experiments indicated that particle size analysis should use sieve agitators, dispersing agent, and 10 or 15 min sieving time for the standard 13-sieve method and 90 s sieving time with dispersing agent for the 3-sieve method.

This master thesis provides an overview of the paper machine with focus on the forming section. The forming section is the first part in the paper machine where the paper pulp is injected through a head box. The paper pulp contains about 99.5% of water and 0.5% fiber. The water as content is reduced by vacuum and gravity. The problem to be studied in this project is related to external rewetting. This is water going back to the paper web from the forming fabric after the dewatering zone. The dewatering is based on vacuum slots under the forming fabric. The vacuum slots absorb water from the soaked paper pulp through the forming fabric. External rewetting causes problem, hence the paper will have a higher dry content when leaving the forming section. The paper should have as low dry content as possible in the end of the forming section. Three different forming fabrics from Albany International were chosen for the project. The structures of the forming fabrics were two different double layers and one plain weave. The performance of the fabrics was studied by 4 different methods. The methods used were 2 different wicking tests, a vacuum dewatering trial and one foulard test. Also micro tomography was done to understand the structure of each design. The main test was a foulard test where the aim was to see in what way the rewetting got affected by different pores sizes. The results showed higher water content for the paper that was on top of the forming fabric with the larger pores.

Master of Science / Department of Statistics / Christopher I. Vahl / Estimation of sample size is an important and critical procedure in the design of clinical trials. A trial with inadequate sample size may not produce a statistically significant result. On the other hand, having an unnecessarily large sample size will definitely increase the expenditure of resources and may cause a potential ethical problem due to the exposure of unnecessary number of human subjects to an inferior treatment. A poor estimate of the necessary sample size is often due to the limited information at the planning stage. Hence, the adjustment of the sample size mid-trial has become a popular strategy recently. In this work, we introduce two methods for sample size re-estimation for trials with a binary endpoint utilizing the interim information collected from the trial: a blinded method and a partially unblinded method. The blinded method recalculates the sample size based on the first stage’s overall event proportion, while the partially unblinded method performs the calculation based only on the control event proportion from the first stage. We performed simulation studies with different combinations of expected proportions based on fixed ratios of response rates. In this study, equal sample size per group was considered. The study shows that for both methods, the type I error rates were preserved satisfactorily.

Background: Despite the adverse demographic and health impact of early marriage, it still occurs in many developing nations including Nigeria. One of the outcomes of early marriage is increase in population size due to the number of years of exposure to the risk of pregnancy of women who marry early. Most of the research on early marriage has been carried out in the Northern and Western zones of the country. The objective of this study was to identify the relationship between early marriage and the outcomes of Number of Children Ever Born (NCEB) and Total Fertility Rate (TFR) in the South East Zone (SEZ) of the country. Methods: Univariate, bivariate and multivariate analysis were carried out on data obtained from 2008 Nigeria Demographic and Health Survey (NDHS) to determine the relationship between NCEB and age at first marriage as well as other independent variables such as woman’s level of education, wealth status, place of abode, husband’s educational level and marital status for ever married women aged 45-49 years. TFR was estimated for all ever married women in the South East Zone as well as those who married at <18 years and those who married at >=18 years of age. A sample size of 2175 comprising all ever married women in the SEZ was used for the study. Results: The findings indicate that there is a significant relationship between NCEB and Age at first marriage as well as woman’s level of education only. The TFR for women who married at <18 years and 18+ was 7.8 and 7.7 respectively. Conclusions: The study has shown that early marriage contributes in some measure to the number of children born in South Eastern Nigeria. However the level of significance is low. The seeming contradiction suggests that there are other influencing factors such as prevailing customs and traditions and shared experiences of the Igbos (the dominant tribe in the study area). Areas of further research are highlighted and recommendations for policy and program implementation are made.

Thesis advisor: Douglas A. Edmonds / Delta morphology is traditionally explained by differences in fluvial energy and wave and tidal energy. However, deltas influenced by similar ratios of river to marine energy can display strikingly different morphologies. Other variables, such as grain size of the sediment load delivered to the delta, influence delta morphology, but these models are largely qualitative leaving many questions unanswered. To better understand how grain size modifies deltaic processes and morphologies I conducted 33 numerical modeling experiments and quantified the effects produced by different grain sizes. In these 33 runs I change the median (0.01 - 1 mm), standard deviation (0.1 - 3 φ), and skewness (-0.7 - 0.7) of the incoming grain-size distribution. The model setup includes a river carrying constant discharge entering a standing body of water devoid of tides, waves, and sea-level change. The results show that delta morphology undergoes a transition as median grain size and standard deviation increase while changing skewness has little effect. At small median grain size and standard deviation, deltas have elongate planform morphologies with sinuous shorelines characterized by shallow topset gradients ranging from 1 x 10<super>-4</super> to 3 x 10<super>-4</super>, and by 1 - 8 stable active channels. At large median grain size and standard deviation, deltas transition to semi-circular planform morphologies with smooth shorelines characterized by steeper topset gradients ranging from 1 x 10<super>-3</super> to 2 x 10<super>-3</super>, and by 14 - 16 mobile channels. The change in delta morphology can be morphodynamically linked to changes in grain size. As grain size increases delta morphology transitions from elongate to semi-circular because the average topset gradient increases. For a given set of flow conditions, larger grain sizes require a steeper topset gradient to mobilize and transport. The average topset gradient reaches a dynamic equilibrium through time. This requires that, per unit length of seaward progradation, deltas with steeper gradients have higher vertical sedimentation rates. Higher sedimentation rates, in turn, perch the channel above the surrounding floodplain (so-called `super-elevation'), resulting in unstable channels that frequently avulse and create periods of overbank flow. The overbank flow is more erosive because the steeper gradient causes higher shear stresses on the floodplain, which creates more channels. More channels reduce the average water and sediment discharge at a given channel mouth, which creates time scales for mouth bar formation in coarse-grained deltas that are longer than the avulsion time scale. This effectively suppresses the process of bifurcation around river mouth bars in coarse-grained deltas, which in turn creates semi-circular morphologies with smooth shorelines as channels avulse across the topset. On the other hand, the finest-grained (i.e. mud) deltas have low topset gradients and fewer channels. The high water and sediment discharge per channel, coupled with the slow settling velocity of mud, advects the sediment far from channel mouths, which in turn creates mouth bar growth and avulsion time scales that are longer than the delta life. This creates an elongate delta as stable channels prograde basinward. Deltas with intermediate grain sizes have nearly equal avulsion and bifurcation time scales, creating roughly semi-circular shapes but with significant shoreline roughness where mouth bars form. / Thesis (MS) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

Thesis (M. Com. (Accountancy))--University of the Witwatersrand, Faculty of Commerce, Law and Management, School of Accountancy, 2014 / Academic and commercial interest in the corporate governance practices of publicly listed companies has increased significantly in recent years (Rossouw, 2005). With high-profile corporate failures such as Enron and WorldCom heightening the interest in corporate governance practices (Rashid, 2011). It has become evident that the performance of well governed firms is superior to that of less well governed firms (Kyereboah-Coleman & Biekpe, 2005). Despite the fact that corporate governance is multi-dimensional (Kyereboah-Coleman & Biekpe, 2005), this study focused on the impact of board composition (defined by the percentage representation of independent non-executive directors on the board) and board size on the firm performance measures namely; Tobin’s Q (TOB), return on assets (ROA), and return on equity (ROE) of firms listed on the Johannesburg Securities Exchange (JSE). Annual data, from the period 2006 to 2012 was used while the analysis of data was done using the Multiple Regression Analysis Model. After having analysed the research results, it was found that no significant relationship exists between the proportion of independent non-executive directors on the board and board size, and firm performance measures. Thus, this research study suggests that performance of South African companies listed on the JSE Securities Exchange is not influenced by board composition and board size.

A thesis submitted to the Faculty of Engineering and The Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering Johannesburg 12 September 2016 / Comminution and leaching unit processes play a major role in extracting valuable minerals from ore. Most of the research reported in the literature has focused on optimising individual unit operations rather than on integrating the whole process. This thesis develops an integrated approach to mineral processing systems and flow sheets and is intended to create a methodology for process synthesis that can be applied throughout the extractive metallurgical industry. This could lead to improved efficiency in the overall process by obtaining optimum recovery and, most important, a reduction in energy and material costs. In order to illustrate the methodology a particular example was chosen, namely optimizing the joint comminution and leaching of a particular gold ore. In this investigation laboratory scale grinding and leaching profiles for a gold feed sample (1700–850 μm) were measured. In a laboratory mill various combinations of grinding media, filling level and ball size were investigated, and of the three ball sizes used (10, 20 and 30mm) breakage was most pronounced for the 20 mm. Thus for instance it was also established that when using a higher filling ( =30%) and a ball size of 30 mm, more energy was consumed but less liberation occurred, thus a lower amount of gold was extracted during a 24-hour leaching period. Finally, the breakage kinetics of the gold ore was looked at. Using a standard population model the breakage and selection function parameters were successfully calculated. An investigation into the dissolution kinetics of gold ore in a solution of NaCN was also done. These were found to depend on the stirring rate, reaction temperature, particle diameter and the concentration of the leachant. The rate increased with the stirring speed, reaction temperature and leachant concentration, but decreased when the particle size was greater. The activation energy for the dissolution was estimated at about 3 kcal/mol. Furthermore, the linear relationship between the rate constant and the reciprocal of the square of the particle size is a strong indication that the gold dissolution process is diffusion-controlled. The experimental results were well-fitted to a shrinking core model. In attempting to understand the results, the researcher carried out a number of experiments that involved an investigation into the relationship between comminution and leaching in terms of energy usage and particle size, the former to establish the most efficient application of energy, and the latter to identify the degree of fineness that would ensure optimal recovery. The Attainable Region (AR) method was then used to establish ways of finding the leaching and milling times required to achieve minimum cost (maximise profit). No work on utilizing the AR technique to minimise the cost of milling and leaching on a real industrial ore has previously been published. The investigation aims to show how the AR technique can be used to develop ways of optimising an industrial process that includes milling and leaching. The experimental results were used to show how this method could be successfully applied to identifying opportunities for higher efficiency when performing these operations. The approach however is general and could in principle be used for any two or more unit operations in determining how the product from one unit should be prepared to feed to the next unit so as to optimize the overall process. / MT2017

MMed, Ophthalmology,Faculty of Health Sciences, University of the Witwatersrand, 2009 / Objectives To determine in a cohort of 69 African patients with large optic discs and large optic cups, that proportion of patients with physiologic cupping (normal eyes) misdiagnosed as glaucomatous. To evaluate the possible relationship between optic disc size and central corneal thickness. Design and method A case series of 69 patients with large discs (vertical disc height measuring 1.8mm) and large cups (vertical cup to disc ratio 0.6) was evaluated to determine what proportion had glaucoma and what proportion was normal. Patients categorized as normal were further evaluated to determine what proportion were previously misdiagnosed and treated for glaucoma. Patients with a suspected diagnosis of glaucoma, normal tension glaucoma or primary open angle glaucoma were recruited from the glaucoma clinic at St John Eye Hospital. Outcome measures included corrected vertical disc height (VDH), vertical cup to disc ratio (CDR), central corneal thickness (CCT), the relationship between VDH and vertical cup height, the relationship between VDH and CCT, adjusted intraocular pressure (A-IOP), retinal nerve fiber layer analysis and visual fields. vii Results Sixty-nine African patients (138 eyes) with large discs and large cups were evaluated. 41 (59%) were females and 28 (41%) were males. The mean age was 56 years. Of the 69 patients, 51 (74%) had physiologic cupping (normal eyes) and 18 (26%) patients were glaucomatous. Of the group of 51 patients with physiologic cupping, there were 9 patients who were previously misdiagnosed with glaucoma and who had received treatment. VDH ranged between 1.9 and 3.2mm (mean ±SD, 2.3±0.26mm). The distribution analysis of VDH measurements noted the largest cluster around 2.3mm. CCT ranged between 454μm and 618μm (mean±SD, 516±37μm). 107 (77.5%) of the 138 eyes had CCT < 544μm. Conclusion Large cup to disc ratio in relation to large disc size can be normal. It can be misdiagnosed as glaucomatous if objective retinal nerve fiber layer analysis is not carried out. In this study, 9 (18%) patients from a group of 51 patients with physiologic cupping were misdiagnosed as glaucomatous. There was no linear correlation between CCT and VDH in this study. Pearson’s correlation coefficient was 0.13. The majority (77.5%) of eyes had thin corneas (CCT < 544μm).

The effects of intrinsic traits on the diversification dynamics have been extensively investigated, with several traits being associated with increase in diversification. On the other hand, the possible negative effects of traits on the diversification of a lineage have been for the most part overlooked. Here we used both the fossil record and molecular data to study the diversification dynamics of Placentalia, focusing on the orders in decline of diversity, and investigated different mechanisms that might control the evolutionary success of the 21 placental orders. More specifically we: 1- determined which of the 21 orders of Placentalia are in decline of diversity (i.e., Decline model); 2- investigated whether the Decline model has a phylogenetic signal; 3- tested the hypothesis that the differences in body size are related to the Decline model; 4- tested the hypothesis that the orders in Decline have lower morphological disparity; 5- investigated whether the orders in decline of diversity, inferred from the fossil record, are the ones with higher extinction risk nowadays. Our analysis indicate that the majority of the orders of placental mammals have a pattern consistent with the Decline model and, although the Decline model is not equally distributed among the placental superorders, there was no significant phylogenetic signal for the orders in diversity decline. We found a positive correlation between the Decline model and the average body size which is in line with previous studies on body size evolution. We argue that such results suggest a complex evolutionary dynamics: larger body size appears to be an evolutionary attractor with lineages showing a tendency to increase in size, however, the increase in body size would be counterbalanced by a higher propensity to Decline. Moreover, we found a the negative correlation between the Decline model and morphological variation. We suggest that such results could indicate two possible scenario: (i) the low morphological variation would cause lineages to loose diversity; (ii) the low morphological variation would be the product of decrease in diversity through extinction selectivity. Finally, we found no correlation between the extinction risk of extant species and the deep time diversity decline, which suggests that the drivers of the current and the past Decline are not the same / O efeito de caracteres intrínsecos na dinâmica de diversificação foram extensamente investigados e diversos caracteres foram associados com aumentos na diversificação. Contudo, os possíveis efeitos negativos de um caractere sobre a diversificação de uma linhagem foram em grande parte ignorados. No presente trabalho integramos o registro fóssil com dados moleculares para estudar a dinâmica de diversificação de Placentalia, focando nas ordens em declínio de diversidade, e investigamos possíveis mecanismos responsáveis por gerar os padrões de diversificação encontrados. Mais especificamente nós: 1- determinamos quais das 21 ordens de Placentalia estão em declínio de diversidade (i.e., Declínio); 2- investigamos se o Declínio apresenta um sinal filogenético; 3- testamos a hipótese de que o tamanho do corpo está relacionado com o Declínio; 4- testamos a hipótese de que as ordens em Declínio possum menor disparidade morfológica; 5- investigamos se as ordens em Declínio, inferido a partir do registro fóssil, são as mesas com maior risco de extinção na atualidade. Nossas análises indicam que a maioria das ordens de mamíferos placentários apresentam um signal consistente com o Declínio e, embora o Declínio não esteja igualmente distribuído entre as superorderns de Placentalia, não há um signal filogenético significativo para as ordens em Declínio. Nossos resultados indicam uma correlação positiva entre o Declínio e o tamanho corporal médio de cada ordem que está de acordo com estudos prévios sobre evolução do tamanho do corpo. Argumentamos que estes resultados sugerem uma dinâmica de evolução complexa: tamanho corpóreo grande seria um atrator evolutivo que gera a tendência das linhagens aumentarem de tamanho, todavia, o aumento do tamanho do corpo seria contrabalançado pela maior susceptibilidade ao Declínio. Outrossim, encontramos uma correlação negativa entre o Declínio e a variação morfológica. Argumentamos que essa correlação poderia indicar dois possíveis cenários: (i) a baixa variação morfológica seria responsável pela redução no número de linhagens e tornaria as ordens mais susceptíveis ao declínio de diversidade; (ii) a baixa variação morfológica teria sido gerada pela diminuição da diversidade. Por último, o risco de extinção das espécies atuais não está correlacionado com o Declínio, o que sugere que os mecanismos responsáveis pelo Declínio no passado e no presente não são os mesmos.