Various hazardous chemical substances are used daily as part of manufacturing and processing. Exposure to these hazardous chemical substances (HCSs) can cause adverse health effects in the exposed workers. Occupational exposure limits (OELs) are used to control exposure to these HCSs and thereby protect workers from the adverse effects that exposure may induce. The aim of this study was to compare South African list of OELs as contained in the Hazardous Chemical Substance Regulations (HCSR) to several developed and developing countries based on two aspects: (1) the number of substances that are selected and regulated by the lists of each country (2) and the overall level of the OELs set by the different countries and jurisdictions. Due to the nature and the large amount of data the study is divided into two parts. The first part is a comparison of South African OELs with nine developed countries and jurisdictions along with the Mine Health and Safety Act Regulation 22.9 (MHSR) of South Africa. The second comparison was conducted between South African and the four developing BRICS countries. BRICS is an acronym for: Brazil, Russia, India, China and South Africa, all are leading developing countries. Substance selection and coverage was compared by analysing the number of overlapping and uniquely regulated OELs that existed between countries. The over-all level of OELs was determined and quantified by using the statistical method, the geometric means of ratios. These ratios were compared in order to establish how the levels of OELs of the South African HCSR compare with the level of the various other countries. Results indicated that there are large and unsystematic differences between the selection of HCSs that are regulated by different countries and jurisdictions. Individual coverage and selection of HCSs between the various developing and developed countries and jurisdictions in the study was inconsistent and dissimilar. A high number of HCSs are regulated by only one of the various countries included in this study. Among the developed countries 20.8% of substances are uniquely regulated, whereas 46% of HCSs are regulated by only one of the various developing countries. According to the geometric means of ratios Occupational Safety and Health Administration (OSHA) is the only jurisdiction in a developed country that has a higher overall level of OELs when compared to South Africa as for the rest of the developed countries they all yielded a lower overall level of OELs. American Conference of Governmental Industrial Hygiene (ACGIH) had the lowest overall level of OELs. When compared with the BRICS countries South Africa had a higher overall level of OELs. The average overall level of OELs differs substantially between the BRICS countries; Russia having the lowest, and Brazil having the highest overall limit when compared relative to South African HCSR. Strong similarities were found between South African HCSR and MHSR indicating national similarity. The South African OELs for HCSs have an overall higher level than the majority of developed and developing countries. Various factors may be responsible for these differences among countries and jurisdictions. These factors include, variations in scientific reasoning, the risk acceptance of the negative impact that various HCSs might induce and the time lags that countries have between updates. Further differences may be explained by the difference in consideration of socio-economical and practical feasibility of an OEL and the predominant industries in a country. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013

Various hazardous chemical substances are used daily as part of manufacturing and processing. Exposure to these hazardous chemical substances (HCSs) can cause adverse health effects in the exposed workers. Occupational exposure limits (OELs) are used to control exposure to these HCSs and thereby protect workers from the adverse effects that exposure may induce. The aim of this study was to compare South African list of OELs as contained in the Hazardous Chemical Substance Regulations (HCSR) to several developed and developing countries based on two aspects: (1) the number of substances that are selected and regulated by the lists of each country (2) and the overall level of the OELs set by the different countries and jurisdictions. Due to the nature and the large amount of data the study is divided into two parts. The first part is a comparison of South African OELs with nine developed countries and jurisdictions along with the Mine Health and Safety Act Regulation 22.9 (MHSR) of South Africa. The second comparison was conducted between South African and the four developing BRICS countries. BRICS is an acronym for: Brazil, Russia, India, China and South Africa, all are leading developing countries. Substance selection and coverage was compared by analysing the number of overlapping and uniquely regulated OELs that existed between countries. The over-all level of OELs was determined and quantified by using the statistical method, the geometric means of ratios. These ratios were compared in order to establish how the levels of OELs of the South African HCSR compare with the level of the various other countries. Results indicated that there are large and unsystematic differences between the selection of HCSs that are regulated by different countries and jurisdictions. Individual coverage and selection of HCSs between the various developing and developed countries and jurisdictions in the study was inconsistent and dissimilar. A high number of HCSs are regulated by only one of the various countries included in this study. Among the developed countries 20.8% of substances are uniquely regulated, whereas 46% of HCSs are regulated by only one of the various developing countries. According to the geometric means of ratios Occupational Safety and Health Administration (OSHA) is the only jurisdiction in a developed country that has a higher overall level of OELs when compared to South Africa as for the rest of the developed countries they all yielded a lower overall level of OELs. American Conference of Governmental Industrial Hygiene (ACGIH) had the lowest overall level of OELs. When compared with the BRICS countries South Africa had a higher overall level of OELs. The average overall level of OELs differs substantially between the BRICS countries; Russia having the lowest, and Brazil having the highest overall limit when compared relative to South African HCSR. Strong similarities were found between South African HCSR and MHSR indicating national similarity. The South African OELs for HCSs have an overall higher level than the majority of developed and developing countries. Various factors may be responsible for these differences among countries and jurisdictions. These factors include, variations in scientific reasoning, the risk acceptance of the negative impact that various HCSs might induce and the time lags that countries have between updates. Further differences may be explained by the difference in consideration of socio-economical and practical feasibility of an OEL and the predominant industries in a country. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013

Positioning itself as an investigation into the affective capacity of transport, this thesis argues that the potential of a city is both composed and revealed through its systems of movement, contending that the sensorial and expressive qualities of a city’s transit govern how its citizens perceive and access the scope of experiences available to them. Essays on movement and identity, the limits of the city, immobility, adaptation, and eccentricities, move in parallel with meditations on departures, arrivals, and the time of transit toward a mandate for an amplification of motion and energy. The thesis traces a route from Ontario through London, Rome, and northern Europe before returning to Toronto only to founder in the region’s gridlock. To free the city’s constricted potential, a new passenger rail line running from Pearson Airport, through Toronto on the Canadian Pacific Rail corridor north of Dupont Road, to the site of Pickering’s future international airport is proposed. The key interchange of the new line, Lake Iroquois Station, is developed in detail, feeding on an intense overlap of historic and contemporary infrastructures. Located just south of the historic First Nations trading trail of Davenport Road at Dupont and Spadina, the station gathers the primary midtown electrical corridor, extensions of the Bathurst and Spadina streetcar lines, the existing University/Spadina subway, and expansions of the city’s cycling network, knotting them together with regional passenger rail in order to transport the city and its imagination.

This thesis presents an investigation into the power transmission limitations imposed on a VSC-HVdc converter by ac system strength and ac system impedance characteristics, quantified by the short circuit ratio (SCR). An important result of this study is that the operation of the converter is not only affected by the SCR’s magnitude, but is also significantly affected by the ac system’s impedance angle at the fundamental frequency. As the ac impedance becomes more resistive, the minimum SCR required at the rectifier side increases from that required for ideally inductive ac impedance, but it decreases at the inverter side. The finite megavolt ampere (MVA) limit of the VSC imposes a further limitation on power transfer, requiring an increase in the value of the minimum SCR. This limitation can be mitigated if additional reactive power support is provided at the point-common-connection. A state-space VSC model was developed and validated with a fully detailed non-linear EMT model. The model showed that gains of the phased-locked-loop (PLL), particularly at low SCRs greatly affect the operation of the VSC-HVdc converter and that operation at low SCRs below about 1.6 is difficult. The model also shows that the theoretically calculated power-voltage stability limit is not attainable in practice, but can be approached if the PLL gains are reduced. The thesis shows that as the VSC-HVdc converter is subject to large signal excitation, a good controller design cannot rely on small signal analysis alone. The thesis therefore proposes the application of optimization tools to coordinate the controls of multiple converters in a dc grid. A new method, the "single converter relaxation method", is proposed and validated. The design procedure of control gains selection using the single converter relaxation method for a multi-converter system is developed. A new method for selecting robust control gains to permit operation over a range of operation conditions is presented. The coordination and interaction of control parameters of multi-terminal VSC are discussed. Using the SCR information at converter bus, the gain scheduling approach to optimal gains is possible. However, compared to robust control gains setting, this approach is more susceptible to system instability.

An institution of cassation has been known and implemented almost within all European countries. In the Republic of Lithuania the aforesaid institution has been known since the interwar period. However, it has experienced lots of reforms and constant developments until present days. The latest reform was carried out only several years ago, and during this reform rather big changes were introduced. The cassation admissibility system is considered to be one of the aforementioned changes. This system allows selecting the cases that should be tried following the cassation proceedings. Thus it implies that not every case could be analysed following the cassation procedure and that certain limits to cassation exist. Namely the adoption of these limits form the hypothesis of this work and under the means of comparative, historical, document analysis, logical, critical and linguistic-systemic analysis methods, while examining the judicial practice, the laws of the Republic of Lithuania, the international legal acts, publications and legal researches, this works aims at establishing whether the adoption of these limits does not limit the person’s right to protect his/her violated right or interest by means of legal remedies determined by legal acts.

The importance of monitoring, and where possible reducing, the level of radiation dose from diagnostic X-ray examinations has been recognised for many years and is becoming of increasing concern. Dose reduction is of particular concern in paediatric radiology, and there are specific problems associated with the monitoring and comparison of radiation doses to children. Any optimisation study relies on a framework of good dosimetry. Two techniques have been developed to improve the collection of patient dose data: the automation of survey techniques to increase the quantity of data collected; and a method of correcting for patient size which reduces one source of variability in the data. An optimisation strategy has been developed, consisting of theoretical simulations, experimental verification and clinical implementation. Monte Carlo techniques were used for the theoretical study, which investigated the effect of beam filtration on radiation dose and image quality for a wide range of parameters, specifically for a neonatal size phantom. Simulations included both radiography of bone in soft tissue and fluoroscopy of iodine and barium based contrast media. The results were assessed in terms of the beam spectra and the absorption and transmission characteristics of the phantom and image receptor. Experimental measurements of dose and contrast were made for a simple slab phantom corresponding to that simulated, and results showed good agreement with those predicted. A further set of experimental measurements were carried out using anthropomorphic phantoms in a clinical setting, which demonstrated how the theoretical predictions translated to clinical practice. A clinical trial of the use of a 0.1mm copper filter for fluoroscopic examinations of infants was performed, and the filter shown to give substantial dose reduction with no significant loss in image quality. Some general recommendations on dose quantities and the application of optimisation strategies to paediatric radiology have been made.

In order to predict future range shifts for invasive species it is important to explore their ability to acclimate to the new environment and understand physiological and reproductive constraints controlling their distribution. My dissertation studied mechanisms by which temperature may affect the distribution of two of the most aggressive plant invaders in North America, Bromus tectorum and Bromus rubens. While Bromus tectorum is dominant in the “cold desert” steppes of the Intermountain region of western North America, B. rubens is one of the severe grass invaders in the “hot deserts” of southwestern North America. I first evaluated whether winter freezing tolerance is the mechanism responsible for the distinct northern range limits of Bromus species. Bromus rubens has a slower rate of freezing acclimation that leads to intolerance of sudden, late-autumn reductions in temperature below -12°C, Bromus tectorum, by contrast, cold hardens rapidly and is not impacted by the sudden severe late-autumn cold. Photosynthetic response to temperature does not explain their current range separation. Bromus species differ little in their photosynthetic temperature responses and the acclimation pattern of photosynthesis. Both species acclimated to a broad range of temperature through the amelioration of Pi regeneration limitation at sub-optimal temperatures and improved carboxylation capacity above the thermal optimum which probably resulted from increased thermostability of Rubisco activase. The effect of elevated temperatures during flowering on the seed yield of Bromus species demonstrates that neither species produces seed at 36°C and above. These thresholds are close to temperatures encountered during flowering in their natural environment. In summary, climatic changes will cause northward range expansion of Bromus species due to less severe autumn and winter, while reproductive failure could cause range contraction at their southern margins.

Canada’s workforce, as well as many other countries, is continuing to age as the baby boomer generation (those born between 1946 and 1964) ages and are remaining in the workforce longer. The number of older workers is estimated to double within the next 10 years (Perry 2010). With increased age, there are a number of factors that could influence worker performance and risk of injury. For example, aging is associated with decreased strength and cardiovascular fitness. However, it is unknown whether a worker’s estimates of how much they can safely lift (based on an approach called psychophysics, which is often used in the design of manual materials handling tasks) is lower for older compared to younger workers. The primary goal of this thesis was to test the hypothesis that psychophysical estimates of maximum acceptable forces would be lower for older workers than younger workers during selected lifting tasks. The secondary goal was to measure a host of variables to provide insights into what factors (e.g. kinematic, strength, cardiovascular) might be influencing potential age-related differences. The experimental testing protocol used a psychophysical approach to identify the maximum acceptable mass of an object during several lifting tasks. Participants comprised a total of 24 female workers (12 older (50+ years old) and 12 younger (20-30 years old)). The primary outcome of interest was the maximum acceptable weight of lift (MAWL) for an 8 hour work day that would allow each participant to ‘work as hard as they can without straining themselves, or becoming unusually tired, weakened, overheated, or out of breath’ (Snook and Ciriello 1991). The participants completed four lifting tasks: floor-to-knuckle height (1 lift/9s and 1 lift/2 min) and knuckle-to-shoulder height (1 lift/2 min and 1 lift/8 hr) by adding or removing lead shot to a lifting box. Tasks were 30 minute in duration; participants could adjust the load mass at any time during the trial. The dependent variables collected were the MAWL (the load mass at the end of the trial), maximum sagittal plane joint angles of the shoulder, hip and knee, overall and body part specific ratings of perceived exertion, and heart rate. Older workers selected MAWL values that were significantly lower (by approximately 24%) than their younger counterparts. These age-related differences were more prevalent for tasks which were constrained by strength (i.e. low frequency) compared to those with large cardiovascular requirements (i.e. high frequency). The only significant difference in the sagittal plane joint flexion angle was for the right hip during the 1 lift/2 min from floor-to-knuckle height lifting task, characterized by 34.4 degree decrease hip angle (more flexed) for the older workers. There were also no significant age-related differences in overall ratings of perceived exertion. The only body part-specific rating of perceived exertion with a significant age-related difference was for the knees, with the younger workers reporting the tasks more taxing on this joint than the older workers. Although there were no age-related differences in absolute heart rate values, the older workers were at a significantly higher percentage of their maximum heart rate. The results of this work suggest there is value in continued research probing whether current ergonomic and work design guidelines need to be updated to accommodate the aging working population. According to the results presented in this study, the current approaches often employed during the design of manual materials handling tasks (i.e. incorporating the loads that 75% of females could perform based on the Snook and Ciriello tables (1991) may not be sufficiently protective for older female workers in the workplace.

Standardization, flexibility and transparency had been the eminent keywords of Modern Architecture that have also provided material for the re-interpretation and re-production of several discussions on concepts like &lsquo / form&rsquo / and &lsquo / function&rsquo / in architecture. This study is an inquiry into a number of different interpretations that scrutinize the intricate relationship between architectural form and function in the 20th century with respect to the concepts defined above. The conceptualization of this thesis will be based on the assumption that function is an inadequate and weak concept for the generation of architectural form. It is in this context that form is accepted as an architectural &ldquo / fragment&rdquo / that attains its autonomy not from the strictures imposed by other architectural fragment like &lsquo / function&rsquo / , &lsquo / structure&rsquo / , &lsquo / program&rsquo / and &lsquo / site / but from an infinite number of internal relationships or &lsquo / design tools&rsquo / as we call. The aim of this study is to propose a project for &ldquo / A Multi &ndash / Functional Hall at METU&rdquo / which has the capability of expanding its limits in future, both physically and conceptually / and investigate the &lsquo / design tools&rsquo / that will direct the steps of transformations in the process of architectural production. Within this framework, the investigation is concerned with the production of a flexible, unstable and indeterminant building, focused on the concepts of &lsquo / transformation of space&rsquo / and &lsquo / constant change&rsquo / , that could be re-designed and re-generated in respect to possible future transformations in the program. Thus, architectural production is defined merely as a &lsquo / step&rsquo / or a &lsquo / snap-shot&rsquo / , controlled by the design tools suggesting the solutions for an ever-lasting transformation as the conditions change.

iv Sheet metal forming technologies are challenged especially by the improvements in the automotive industry in the last decades. To fulfill the customer expectations, safety requirements and market competitions, new production technologies have been implemented. This study focuses on the assessment of conventional and new sheet metal forming technologies by performing a systematic analysis. A geometry spectrum consisting of six different circular, elliptic, quad cross-sections are selected for the assessment of conventional deep drawing, hydro-mechanical deep drawing and high-pressure sheet metal forming. Within each cross-section, three different equivalent drawing ratios are used as a variant. More than 200 numerical experiments are performed to predict the forming limits of three competing processes. St14 stainless steel is used as the material throughout the assessment study. The deformation behavior is described by an elasto-plastic material model and all numerical simulations are carried out by using dynamic-explicit commercial The process validation is done by interpreting the strain results of numerical experiment. Therefore, the reliability of predictions in the assessment study highly depends on the quality of simulations. The precision of numerical experiments are verified by comparing to NUMISHEET benchmarks, analytical formulation, and experiments to increase the assets of the assessment study. The analyses revealed that depending on the workpiece geometry and dimensional properties certain processes are more preferable for obtaining satisfactory products. The process limits for each process are established based on the analyzed crosssections of the spectrum. This data is expected to be useful for predicting the formability limits and for selecting the appropriate production process according to a given workpiece geometry.Dynamic-explicit FEM, Deep drawing, Hydroforming, Forming limits, Process evaluation