<p>The purpose of the study was to investigate levels of occupational stress experienced by police officers and the strategies used to cope with stress. The study findings are based on a sample of 104 police officers from six police stations within the Cape Town area. The results indicated that participants have been in the police service for an average of 7.72 years, and have worked an average of 4.8 years at their present stations. The majority of participants are between 26-30 years old (31%), male (75%), married(51%), coloured (65%), constables (45%), Afrikaans speaking (47%), and have a matric qualification (70%). The Spielberger Police Stress Survey and the Brief COPE Inventory were used as data collection tools. The findings indicated that police officers were experiencing moderate levels of stress as an outcome of inherent and organisational occupational demands. Secondly, police officers were more likely to use problem-focussed coping strategies to manage occupational stress than maladaptive strategies. The limited use of avoidance coping strategies was surprising, given the elevated prevalence of both physical and psychological disorders within the police context. The results indicated no significant association between levels of distress and avoidance coping strategies. The potential adverse outcomes of severe stress within this group affect&nbsp / society in general more than stress from most other occupational groups. Addressing persistent stress within the organisation is imperative in ensuring a well-functioning police service, and ultimately, a secure and healthy society.</p>

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No description available.

No description available.

Motivated by the motion of a ship in a heavy sea, a mathematical model for the vertical impact of a two-dimensional solid body onto a half-space of quiescent, inviscid, incompressible fluid is formulated. No solutions to the full problem are known, but in the case when the impacting body has small deadrise angle (meaning that the angle between the tangent to the profile and the horizontal is everywhere small) a uniformly valid solution is obtained by using the method of matched asymptotic expansions. The pressure on the body is calculated and is in fair agreement with experimental results. The model is generalised for more complicated impacts and the justifications for the model are discussed. The method is extended to three-dimensional bodies with small deadrise angle and solutions are obtained in some special cases. A variations! formulation of the leading order outer problem is derived, which gives information about the solution and leads to an fixed domain scheme for calculating solutions numerically. A partial linear stability analysis of the outer problem is given which indicates that entry problems are stable but exit problems are unstable to small perturbations. A mathematical model for the effect of a cushioning air layer between the body and the fluid is presented and analysed both numerically and in appropriate asymptotic limits. Finally, the limitations of the models are discussed and directions for future work indicated.

“Rural electrification” is a key element in the global energy development agenda. While being a developing country, Sri Lanka is enroot to achieve 100% of electrification at present. After the civil war ended in 2009 which lasted for more than 25 years, there has been much focus to fulfill the energy needs of the country. But the studies carried out to assess the impact of electrification are very much limited. This study focuses on meeting the gap of carrying out a scenario analysis of rural electrification and assessing the socio economic impact of electrification. The major focus has been given to see how energy system of a newly electrified village will vary over time. The research intends to identify how far the strategies used to implement a policy is realistic in the real world. Also the research extends to apply the proposed strategies to the energy model and analyze the behavior of the model. During the study a survey was carried out in a rural village in southern part of Sri Lanka and the data obtained were used to model the energy system of the village using a software called - LEAP (Long Range Energy Alternative Planning System). The energy system is simulated under different scenarios to analyze if certain strategies in the policy have been implemented in the village. Two scenarios were energy efficient lighting and energy efficient cooking stoves. A total energy balance has been carried out for the target sample with an analysis of global warming potential of the activities of the target family. The total energy consumption variation with the electrification and the percentage of energy consumed as electricity over time has been analyzed. Further the socio economic impacts of electrification have been studied. The impact of agricultural usage and economic productivity with electricity has been studied. The qualitative measures like attitude changes, modernization &amp; technology adaptation were addressed to the extent possible.

The objective of this study is to address the gap that exists in the literature regarding quantifiable guidelines, benchmarks and consistency of applications. During the research acceptable benchmarks for the calculation or quantification of the elements linked to materiality and audit risk were found. The benchmarks are in compliance with the practices and the requirements of the ISAs and regulations. Models and benchmarks based on literature were used as a basis and modified for application in the auditing environment. The combination of literature, responses from public practitioners and experience based on best practices resulted in the development of a modified risk-based assessment model. The conclusion from the empirical study indicated that there are no defined rules or basis for calculating materiality and audit risk. The inconsistencies in responses indicate that audit firms and developer of key concepts interpret and apply the above-mentioned term different in practice. The interpretations of the relevant ISAs, appear to be conceptually correct as no major non-compliances were identified. Various instances indicated that there is a lack of guidance with regard to the quantification or qualification of benchmarks. The implementation of the Sarbanes-Oxley Act (2002) was an event that leads to the consideration of more conservative benchmarks. The most consistent benchmark that stood the test of time was Discussion paper 6 (1984). The 30 years since the development of these benchmarks indicate that little attention has been given to one of the most complex issues in auditing. Companies within different industries are not generic and exceptions will occur where the auditor needs to apply professional judgment to accommodate the deviations. Further research is required to assist the audit professionals and students in the development of consistent benchmarks to increase the reputation of the profession. The conclusion drawn from this study is that audit materiality and audit risk has a significant impact on the audit process as even the audit report is influenced by proper audit planning and guidelines to support the auditor in audits. / MCom (Accountancy), North-West University, Vaal Triangle Campus, 2013

The experiments presented in this thesis provide novel insight into two scarcely studied areas in the field of lateral hip impact biomechanics. The high energy nature of hip impacts requires high sampling rates for accurate study of hip impact dynamics. However, to date only optical motion capture, with relatively lower sampling rates (240-400 Hz), has been used to measure pelvic deflection during hip impact experiments with human participants. As such, the results from the first study compared the differences between two measurement systems (3D optical motion tracking and 2D high speed videography) in measuring common variables of impact biomechanics (peak force, time to peak force, peak deflection, time to peak deflection and energy absorbed). Although significant differences were seen between systems in measuring TFmax and Emax, the magnitude of differences were at or below 5% of the total magnitude of each measured variable. Furthermore, averaging impacts within a subject reduced the differences between systems for Emax. Furthermore, this study showed the effect of sampling rate on measuring hip impact dynamics, and how sampling at lower frequencies affects the aforementioned variables. Tests on the effect of sampling rate found differential effects contingent on the dependent variable measured. Sampling as low at 300 Hz, significantly reduced measures of Fmax and Dmax, but only by on average 0.7 and 0.5 %, respectively. Whereas measures of TFmax and TDmax increased by on average 9.5 and 6.8 %. Sampling Emax at 500 Hz and 300 Hz increased measures of impact absorption by 2.2 and 2.8 % respectively. Sampling at 4500 Hz was the lowest sampling rate that was not significantly different from 9000 Hz across all dependent variables. The second study in this thesis investigates the influence of contact area on load distribution during lateral hip impacts. In summary, this study shows that all three time-varying signals (Ft, FTt and Dt ) were significantly correlated with time-varying contact area (Ct). These results lend support to the possibility of modeling lateral hip impacts with contact models, but provide little support for a Hertzian model adaptation. Analysis on the relationships between body mass and BMI found both anthropometric measures to correlate significantly with peak impact force, but not with peak impact force directed to the greater trochanter. These results bring into question the feasibility of modeling hip fracture risk with body mass or BMI as inputs, without further investigating the distribution of impact force to the greater trochanter. In this study only contact area was significantly correlated with all measures of GT specific loading, and has never before been implemented in predictive modelling of hip fracture risk. Finally, this study found that although effective mass, total body mass and BMI were significantly correlated with the contact area at peak force, they only accounted for 21, 22 and 33% of the variance in CA. Altogether, this study sheds new light on the role that contact area plays in lateral hip impact loading and the importance of understanding load distribution during lateral hip impacts. It also highlights the importance of moving towards predictive models that incorporate more robust estimate of body composition and geometry, with hopes that these will better help estimate the risk of hip fracture. Overall, this thesis provides insight into the expected differences between measuring hip impact dynamics with two, relatively different measurement techniques. In addition, it highlights the need for further study on the relationship between contact geometry and hip fracture risk, something not currently implemented in most hip fracture risk models.

Introduction: The Canadian Standards Association (CSA) Z94.3-07 ballistic impact test for industrial lenses, tests the ability of a lens material to withstand the impact of a 6.4 mm diameter steel ball travelling at a speed of 46.5 ± 0.5 m/s. The specific testing is waived if the lens made of various materials meets a minimum centre thickness requirement. New lens materials, like Hi-Vex, are not included in this list. The first study compared the breakage speed of Hi-Vex lenses to CR39 lenses at different conditioned temperatures. In the process of carrying out the literature review, it became apparent that the definition of lens failure varied. This led to the question as to how naïve individuals may interpret a National Standard definition of lens failure after being impacted by a missile. Naïve subjects were asked to classify impacted lenses as either pass or fail based on the written CSA Z94.3-07 failure criterion. Purpose:   Study 1: To investigate the impact resistance of a mid-index plastic lens material Hi-Vex (n=1.56) at different temperatures. Study 2: To investigate if people actually understood what the CSA classifies as a failed lens. Methods:  Study 1: Two groups of plano hard coated lenses were tested: CR39 and Hi-Vex. Lenses were ordered with 3mm centre thickness, cut to 50mm diameter and edged to achieve the Hide-a-Bevel® which was in agreement with the CSA requirement for prescription industrial safety lenses and frames. A pneumatic gun was used to propel a 6.35mm steel ball at the centre of each lens. Impact speed was varied using the Zippy Estimation by Sequential Testing (ZEST) protocol to determine the threshold breakage speed. Combined uncertainties as defined in the International organization for standardization (ISO) Guide to the expression of uncertainty in measurement were used to determine the statistical significance of all comparisons of the data sets. Study 2: Ten graduate students from the School of Optometry and ten patients from the general public were given 25 spectacle lenses that had been subjected to the ballistic impact test. They were asked to classify the lenses as either a pass or fail after reading the definition of a failure under the ballistic impact test in CSA Z94.3-07 clause 6.1.3.1. Lenses were presented to the participants in the same order. The responses of both groups of participants were compared to the classification of two experienced researchers who agreed on 100% of the lens outcomes. Results:  Study 1: The threshold breakage speeds of the industrial thickness Hi-Vex and CR39 lenses at 24°C were 50.88m/s and 50.64 m/s and at -29°C, 52.57m/s and 52.56 m/s respectively. Both comparisons were not statistically significant. The corresponding threshold breakage speeds for Hi-Vex and CR39 lenses at -49°C were 66.38m/s and 49.66m/s and at 50°C were 57.01m/s and 53.54m/s respectively. Both comparisons were statistically significant. Study 2: There were only two lenses in which all participants agreed with the outcome. These lenses were failed lenses. The naïve subjects were more likely to classify a lens that passed as a failure than a failed lens as a pass. This trend was more obvious in the general public results although the results across the various lenses for the graduate students and general public were not statistically different. Conclusions:  Study 1: We found that the mean breakage speeds of the Hi-Vex and CR39 lenses were greater than the level required of eye protector lenses by the Standards American National Standards institute (ANSI) Z87.1-2010 and CSA Z94.3-07. Hi-Vex was also superior to CR39 at more extreme temperatures with a threshold breakage speed of 57.01±3.51m/s at 50°C and 66.38±4.00m/s at -49°C. Although its impact resistance was less than that of both Trivex and Polycarbonate lenses, Hi-Vex may provide an acceptable level of impact protection in industrial settings. This is the first study to concomitantly assess impact resistance of a new lens material as well as compare the impact resistance at various temperatures. Study 2: Simply reading the definition of a lens failure is insufficient. Some type of training with actual lenses may be necessary. Whether revising the text of the Standard or repeating the instructions several times would reduce this problem is uncertain. Both the graduate students and general public tended to be more conservative in their classification of failure. If there were any visible damage to the lens as a result of the impact, at least one person would classify the lens as a failure regardless of whether the damage met the CSA definition. This result suggests that the vision care community and CSA may need to educate the public on the meaning of impact resistance of eye protectors.

Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2009.