Master thesis is focused on the influence of interference fit on rolling bearing life. The first part of thesis deals with the theoretical knowledge, that is necessary for the solution. The influence of interference fit was investigated of inner ring on shaft and outer ring in housing bore for recommended tolerance classes. Interference fit was solved on cylindrical roller bearing and tapered roller bearing. Analytical and numerical approach was used for the solution. A static analysis of bearing was made using program ANSYS Workbench in numerical section. The output of analysis was maximum shear stress under the contact surface, which result is contact fatigue of bearing. Bearing life was determined by life factor, which indicates bearing life with interference fit compared to bearing without interference fit.

The primary objective of the study was to investigate the relationship between work engagement and hope and to determine the possible impact on productivity within an agri-business. For the purpose of the study, we used two measures, namely: • The Utrecht Work Engagement Scale was used to measure work engagement • The Dispositional Hope Scale was used to measure hope. The questionnaires were completed by 341 respondents of the relevant agribusiness. The respondents represented all the divisions in the business. The research results showed that there was a significant correlation between work engagement and hope. Moreover, the literature review showed that work engagement and hope are playing a definite role in the productivity of any business. / MBA, North-West University, Potchefstroom Campus, 2014

The primary objective of the study was to investigate the relationship between work engagement and hope and to determine the possible impact on productivity within an agri-business. For the purpose of the study, we used two measures, namely: • The Utrecht Work Engagement Scale was used to measure work engagement • The Dispositional Hope Scale was used to measure hope. The questionnaires were completed by 341 respondents of the relevant agribusiness. The respondents represented all the divisions in the business. The research results showed that there was a significant correlation between work engagement and hope. Moreover, the literature review showed that work engagement and hope are playing a definite role in the productivity of any business. / MBA, North-West University, Potchefstroom Campus, 2014

As a result of concern about the effects of CO2 emssions on the global warming, there is increasing pressure to reduce such emissions from power generation systems. The use of biomass co-firing with coal in conventional pulverised fuel power plants has provided the most immediate route to introduce a class of fuel that is regarded as both sustainable and carbon neutral as it produces less net CO2 emissions. In the future it is anticipated that increased levels of biomass will be required to use in such systems to accomplish the desired CO2 emissions targets. The use of biomass, however, is believed to result in severe fireside corrosion of superheater and reheater tubing and cause unexpected early failures of tubes, which can lead to significant economic penalties. Moreover, future pulverised fuel power systems will need to use much higher steam temeptures and pressures to increase the boiler efficiency. Higher operating temperatures and pressures will also increase the risk of fireside corrosion damage to the boiler tubing and lead to shorter component life. Predicting the remaining service life of superheater and reheater tubes in coal-biomass fired power plants is therefore an important aspect of managing such power plants. The path to this type of failure of heat exchangers involves five processes: combustion, deposition, fireside corrosion, steam-side oxidation, and creep. Various models or partial models each of these processes are available from existing research, but to fully understand the impact of new fuel mixtures (i.e. biomass and coal) and changing operating conditions on such failures, an integrated model of all of these processes is required. This work has produced an integrated set of models and so predicted the remaining service life of superheater/reheater tubes based on the three frameworks which have been developed by analysing those models used in depicting the five processes: one was conceptual and the other two were based on mathematical model. In addition, the outputs of the integrated mathematical models were compared with the laboratory generated data from Cranfield University as well as historical data from Central Electricity Research Laboratories. Furthermore, alternative models for each process were applied in the model and the results were compared with other models results as well as with the experimental data. Based on these comparisons and the availability of models constants the best models were chosen in the integrated model. Finally, a sensitivity analysis was performed to assess the effect of different model input values on the residual life superheater and reheater tubing. Mid-wall metal temperature of tubes was found to be the most important factor affecting the remaining service life of boiler tubing. Tubing wall thickness and outer diameter were another critical input in the model. Significant differences were observed between the residual life of thin-walled and thick-walled tubes.

This Dissertation covers three aspects of General Relativity: inequivalent Einstein metrics on Lie Group Manifolds, proving the Hoop Conjecture for Black Rings, and investigating ergoregions in magnetised black hole spacetimes. A number of analytical and numerical techniques are employed to that end. It is known that every compact simple Lie Group admits a bi-invariant homogeneous Einstein metric. We use two ansatze to probe the existence of additional inequivalent Einstein metrics on the Lie Group SU (n). We provide an explicit construction of 2k + 1 and 2k inequivalent Einstein metrics on SU (2k) and SU (2k + 1) respectively. We prove the Hoop Conjecture for neutral and charged, singly and doubly rotating black rings. This allows one to determine whether a rotating mass distribution has an event horizon, that it is in fact a black ring. We investigate ergoregions in magnetised black hole spacetimes. We show that, in general, rotating charged black holes (Kerr-Newman) immersed in an external magnetic field have ergoregions that extend to infinity near the central axis unless we restrict the charge to q = amB and keep B below a maximal value. Additionally, we show that as B is increased from zero the ergoregion adjacent to the event horizon shrinks, vanishing altogether at a critical value, before reappearing and growing until it is no longer bounded as B becomes greater than the maximal value.

The aim of this study is to determine the mechanical characteristics of the filament wound composite tubes working under internal pressure loads, generating data for further investigation with a view of estimating the remaining life cycle of the tubes during service. Data is generated experimentally by measuring the mechanical behavior like strains in hoop direction, maximum hoop stresses that are formed during internal pressure loading. Results have been used to identify and generate the necessary data to be adopted in the design applications. In order to determine these parameters, internal pressure tests are done on the filament wound composite tube specimens according to ASTM D 1599-99 standard. The test tubes are manufactured by wet filament winding method, employing two different fiber types, two different fiber tension settings and five different winding angle configurations. The internal pressure test results of these specimens are studied in order to determine the mechanical characteristics, and the effects of the production variables on the behavior of the tubes. Pressure tests revealed that the carbon fiber reinforced composite tubes exhibited a better burst performance compared to the glass fiber reinforced tubes, and the maximum burst performance is achieved at a winding angle configuration of [&plusmn / 54&deg / ]3[90&deg / ]1. In addition, the tension setting is found not to have a significant effect on the burst performance. The burst pressure data and the final failure modes are compared with the results of the ASME Boiler and Pressure Vessel Code laminate analysis, and it was observed that there is a good agreement between the laminate analysis results and the experimental data. The stress &ndash / strain behavior in hoop direction are also studied and hoop elastic constants are determined for the tubes.

Abstract: Northern rural Indigenous communities in Canada are facing many challenges getting regular access to nutritious foods, primarily due to the high cost of market food, restricted availability of nutritious foods, and lack of government support for nutritious food programs. The consequences of food insecurity in this context are expressed in high rates of diabetes, heart disease, and childhood obesity. Many Indigenous communities are responding to issues around healthy food access by attempting to rebuild local food capacity in their specific regions. Important first steps have been taken in developing local food initiatives, yet it remains to be seen what impact these initiatives are having on improving northern food security. This paper explores this question by working with a remote fly in community in the sub-arctic region Ontario to construct a hoop house and develop a school based community gardening program. By using a community-based participatory approach, it was determined that hoop house and gardening initiatives in rural, northern settings have the potential to build up local food production; can develop the skills and knowledge of community members; can engage and involve youth in growing local food; and do align with land-based food teachings. We show that despite widespread and multidimensional community hardships, there was considerable community buy-in and support to the project, giving hope for future development, and providing important insight for those seeking to initiate similar gardening, hoop house, or greenhouse initiatives in northern Indigenous communities. Abstract 2: Indigenous peoples of what is now known as Canada have experienced rapid lifestyle changes as a result of European contact. Indigenous food systems were systematically eroded by the Canadian government, leading to extremely high rates of food insecurity, and diet related disease. The complicated dynamics and interventions contributing to the erosion of local knowledges have forced a dependence on a market-based food system in remote and northern Indigenous communities in Canada. Communities are experiencing a double burden of the unaffordability or inaccessibility of traditional foods from the land, and the exorbitantly high cost and reduced availability of quality market foods largely due to the cost of shipping to these regions. The entanglement of local practices and global food systems is multifaceted and complex, thus the solution to food insecurity challenges are met with the burden of navigating both the local and the global. The purpose of this article is to analyze local meanings around food in a remote sub-Arctic First Nation in Ontario within the context of “coloniality” and global food systems. Drawing from the work of Walter Mignolo, and his concept of “border thinking”, this article explains the complex subsistence practices in the Canadian north and how they are located within a larger global framework. We show that by pinpointing potential “cracks” in the dominant Western epistemic as border thinking, a more useful understanding of food procurement strategies can come to light and offer new direction for culturally appropriate and sustainable food initiatives in the North.

When looking at the society of today, we get a picture of a society that has lost hope in their lives. This picture also has an effect on the church. Regarding this phenomenon is the remark of Gerard Dekker that the church has become a fringe phenomenon and that the church has lost contact with the world. The church is in a situation of uncertainty and in a search of identity. The use of symbolism and rituals provides identity and security. When a person is confronted with the meaning of the symbol that is been used, it helps that person to give meaning to its life on to give hope for that person. But for this to happen it is necessary that the symbols are being used correct and from the basis of the Scripture. The main place were the symbols and rituals are being used is in the place of public worship. Therefore it is necessary that we will understand what happens in the public worship and who the person is that comes to the public worship. It is also necessary to look at reasons for the insufficient use of symbols in the public worship. In a study that is being made we find that the most significant aspect on the preaching is the atmosphere that there is in the public worship. The church lives in a time of changes and these changes have an affect on the church and the preaching. The public worship is also a creative process were the role of the Scripture, the traditions and the context are important. When using symbols in the public worship we have to look at the communication theory of Ricoeur. For Ricoeur the narrative plays an important role. The process of understanding is for him a creative process where he makes use of stories, metaphors and symbols. From his communication theory it is important that the listener are included. The use of symbols is for him a help in understanding. The symbols also have a double significance, namely unveiling and concealing. The thesis also shows out the role that the Reformation, the Modernism and the Post Modernism have on a person and the way we understand the Word of God. The use of symbols is helpful in the communication of the Word of God to the Post Modern person. The challenge for the preaching is that the symbols are being used in a manner that the other reality is being communicated to the Post Modern person. The last two chapters of the thesis concentrates on the role that symbols plays in our lives; the characteristic of symbols; the conditions for the use of symbols and the use of symbols and rituals. When it comes to the use of symbols we see that these symbols gives meaning and hope to a person. / Dissertation (MA (Theology))--University of Pretoria, 2006. / Practical Theology / unrestricted

In post-apartheid South Africa, Coloured communities are engaged in reconstructing identities and social histories. This study examines the representation of community, identity, culture and historic memory in two films about Westbury, Johannesburg, South Africa. The films are Westbury, Plek van Hoop, a documentary, and Waiting for Valdez, a short fiction piece. The ambiguous nature of Coloured identity, coupled with the absence of recorded histories and unambiguous identification with collective cultural codes, results in the representation of identity becoming contested and marginal. Through constructing narratives of lived experience, hybrid communities can challenge dominant stereotypes and subvert discourses of otherness and difference. Analysis of the films reveals that the Coloured community have reverted to stereotypical documentary forms in representing their communal history. Although the documentary genre lays claim to the representation of reality and authentic experience, documentary is not always an effective vehicle for the representation of lived experience and remembered history. Fiction can reinterpret memory by accessing the emotional textures of past experiences in a more direct way.

Metal pipes are sometimes swaged by a metal cone to enlarge them, which increases the strain in the material. The amount of strain is important because it affects the burst and collapse strength. Burst strength is the amount of internal pressure that a pipe can withstand before failure, while collapse strength is the amount of external pressure that a pipe can withstand before failure. If the burst or collapse strengths are exceeded, the pipe may fracture, causing critical failure. Such an event could cost the owners and their customers millions of dollars in clean up, repair, and lost time, in addition to the potential environmental damage. Therefore, a reliable way of estimating the burst and collapse strength of strained pipe is desired and valuable. The sponsor currently rates strained pipes using the properties of raw steel, because those properties are easily measured (for example, yield strength). In the past, the engineers assumed that the metal would be work-hardened when swaged, so that yield strength would increase. However, swaging introduces anisotropic strain, which may decrease the yield strength. This study measured the yield strength of strained material in the transverse and axial direction and compared them to raw material, to determine the amount of anisotropy. This information will be used to more accurately determine burst and collapse ratings for strained pipes. More accurate ratings mean safer products, which will minimize risk for the sponsor’s customers. Since the strained metal has a higher yield strength than the raw material, using the raw yield strength to calculate burst and collapse ratings is a conservative method. The metal has even higher yield strength after strain aging, which indicates that the stresses are relieved. Even with the 12% anisotropy in the strained and 9% anisotropy in the strain aged specimens, the raw yield strengths are lower and therefore more conservative. I recommend that the sponsor continue using the raw yield strength to calculate these ratings. I set out to characterize the anisotropic nature of swaged metal. As expected, the tensile tests showed a difference between the axial and transverse tensile strength. The correlation was 12% difference in yield strength in the axial and transverse directions for strained material and 9% in strained and aged material. This means that the strength of the metal in the hoop (transverse) direction is approximately 10% stronger than in the axial direction, because the metal was work hardened during the swaging process. Therefore, the metal is more likely to fail in axial tension than in burst or collapse. I presented the findings from the microstructure examination, standard tensile tests, and SEM data. All of this data supported the findings of the mini-tensile tests. This information will help engineers set burst and collapse ratings and allow material scientists to predict the anisotropic characteristics of swaged steel tubes.