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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

On the Design of an Analog Front-End for an X-Ray Detector

Amin, Farooq ul January 2009 (has links)
Rapid development in CMOS technology has resulted in its suitability for the implementation of readout front-end systems in terms of high integration density, and low power consumption yet at the same time posing many challenges for analog circuits design like readout front-end. One of the significant challenges is the low noise design for high speed front-end systems, while at the same time minimizing the power consumption as much as possible. A high speed, low noise, low power, and programmable readout front-end system is designed and implemented for an X-ray detector in CMOS 0.18 m technology in this thesis work. The front-end system has a peaking time of 10 ns, which is the highest speed ever reported in the published work. The front-end system is designed to achieve low noise in terms of ENC, and a low power consumption of 2.9 mW. The detector capacitance is the most dominating parameter to low noise, which in turn is directly related to the power consumption. In this thesis work an ENC of 435 electrons is achieved for a detector capacitance of 5 pF and an ENC of 320 electrons for a detector capacitance of 3 pF. Based on the comparison to related published work, a performance improvement of at least two times is achieved taking peaking time, power, ENC, and detector capacitance all into consideration. The output pulse after amplification has peak amplitude of 300 mV for a maximum injected charge of 40000 electrons from the detector. The readout front-end system noise performance is strongly dependent on the input MOSFET type, size, and biasing. In this work a PMOS has been selected and optimized as the input device due to its smaller 1/f noise and high gain as compare to NMOS when biased at same currents. The architecture designed in this work consists of a folded cascode CSA with extra cascode in first stage, a pole-zero cancellation circuit to eliminate undershoot, a shaper amplifier, and integrators using Gm-C filter technique. All of these components are optimized for low power while meeting the noise requirements. The whole front-end system is programmed for peaking times of 10, 20, and 40 ns. The programmability is achieved by switching different capacitors and resistors values for all the poles and zeros in the front-end, and by switching parallel transconductance in the Gm-C filters. Finally fine tuning of all the capacitance, resistance, and transconductance values is done to achieve required performance.
82

In search of standards for forest carbon offset projects in BC : a review of Georgian and Californian state standards

Iverson, Chad 02 December 2009 (has links)
Forests represent both, one of the strongest drivers of, and solutions to, the rapid shift in the earth’s climate. Integrating the use of forests as a cost effective solution into emerging global carbon markets however has proven extremely difficult. The incentive for companies to utilize carbon credits as a means to offset emissions is heavily dependent upon the credibility of the project that created it. The difficulty proving the credibility of forest projects is largely due to the inherent variation associated with forest environments. British Columbia’s pine beetle epidemic provides an extreme example of just how quickly vast carbon sinks can suddenly become sources. As such, the creation of standards to ensure the security of carbon sequestered by forest projects has proven to be instrumental in encouraging their acceptance into the market. British Columbia has recognized that its forests play an integral role in its contribution to the global carbon cycle. As a result, heavy consideration is being made as to how this resource may be integrated as a source of carbon offsets for its own Cap-and-Trade market. This will mean establishing specific standards for forest projects in a BC context. This report reviews two regional standards from the states of Georgia and California, which could be applied as templates for a set of BC specific protocols for forest carbon sequestration projects. It is intended that through a comparison and analysis of these standards that potential problems faced in applying similar standards here will be identified.
83

Caregivers' experiences of the South African judicial system after the reporting of child sexual abuse / N.L. Paulsen.

Paulsen, Nicole January 2013 (has links)
Child sexual abuse (CSA) is found to occur in alarming proportions worldwide. In South Africa, children represent almost half of the victims of known sexual abuse, and this is becoming a great concern, even being described as a silent epidemic. This alarming fact as well as the researcher’s experiences as a social worker in this field, resulted in her reviewing literature, in order to gain further insight into the current situation in South Africa. It was discovered that the number of successful CSA court cases reported to the Childline Western Cape centres, was significantly low, and that numerous complaints were being received by her colleagues at Childline from caregivers, regarding their dissatisfaction with the judicial system after reporting CSA. This dissertation therefore serves as a qualitative exploration of caregivers’ experiences of the South African judicial system after CSA has been reported. For the purpose of this study, the researcher used a descriptive qualitative research design so as to thoroughly describe the caregivers’ experiences. Semi-structured interviews were conducted with eight participants to gain rich descriptions of their experiences in this area. Three main themes that emerged through the content analysis were: the experiences with officials from the SAPS as part of the judicial system; the experiences with regard to social service delivery; and the experiences with the court and personnel as part of the judicial system. Several conclusions were drawn. The first was that there were both positive and negative experiences with officials from SAPS. A further conclusion was that the lack of knowledge about procedures needing to be followed in cases of CSA, as well as the uncertainty shown by some SAPS officials with regard to how to go about dealing with child victims of sexual abuse, gave some participants the impression that SAPS officials lack adequate training in this regard The researcher concluded from the empirical findings and the literature that there is a general sense that CSA investigations are poorly conducted. Another conclusion was that literature on statutory social service delivery in South Africa and the evaluation thereof seemed sparse. However, from the empirical findings regarding the participants’ descriptions, their experiences, particularly with statutory social workers, were negative. Finally, the researcher concluded that though literature indicated that several changes had been made in the judicial system so as to better deal with child victims of sexual abuse, the experiences of the participants indicated that challenges are still being experienced. The empirical findings indicated that caregivers of child victims of sexual abuse and their children had experienced great frustration when dealing with the judicial system after CSA had been reported. These frustrations were due to the investigation of CSA cases, the court process, and the lack of communication from prosecutors and other professionals in the judicial system. / Thesis (MSW)--North-West University, Potchefstroom Campus, 2013.
84

Caregivers' experiences of the South African judicial system after the reporting of child sexual abuse / N.L. Paulsen.

Paulsen, Nicole January 2013 (has links)
Child sexual abuse (CSA) is found to occur in alarming proportions worldwide. In South Africa, children represent almost half of the victims of known sexual abuse, and this is becoming a great concern, even being described as a silent epidemic. This alarming fact as well as the researcher’s experiences as a social worker in this field, resulted in her reviewing literature, in order to gain further insight into the current situation in South Africa. It was discovered that the number of successful CSA court cases reported to the Childline Western Cape centres, was significantly low, and that numerous complaints were being received by her colleagues at Childline from caregivers, regarding their dissatisfaction with the judicial system after reporting CSA. This dissertation therefore serves as a qualitative exploration of caregivers’ experiences of the South African judicial system after CSA has been reported. For the purpose of this study, the researcher used a descriptive qualitative research design so as to thoroughly describe the caregivers’ experiences. Semi-structured interviews were conducted with eight participants to gain rich descriptions of their experiences in this area. Three main themes that emerged through the content analysis were: the experiences with officials from the SAPS as part of the judicial system; the experiences with regard to social service delivery; and the experiences with the court and personnel as part of the judicial system. Several conclusions were drawn. The first was that there were both positive and negative experiences with officials from SAPS. A further conclusion was that the lack of knowledge about procedures needing to be followed in cases of CSA, as well as the uncertainty shown by some SAPS officials with regard to how to go about dealing with child victims of sexual abuse, gave some participants the impression that SAPS officials lack adequate training in this regard The researcher concluded from the empirical findings and the literature that there is a general sense that CSA investigations are poorly conducted. Another conclusion was that literature on statutory social service delivery in South Africa and the evaluation thereof seemed sparse. However, from the empirical findings regarding the participants’ descriptions, their experiences, particularly with statutory social workers, were negative. Finally, the researcher concluded that though literature indicated that several changes had been made in the judicial system so as to better deal with child victims of sexual abuse, the experiences of the participants indicated that challenges are still being experienced. The empirical findings indicated that caregivers of child victims of sexual abuse and their children had experienced great frustration when dealing with the judicial system after CSA had been reported. These frustrations were due to the investigation of CSA cases, the court process, and the lack of communication from prosecutors and other professionals in the judicial system. / Thesis (MSW)--North-West University, Potchefstroom Campus, 2013.
85

Punching Shear Behaviour of Thick Reinforced Concrete Slabs

Netopilik, Robert J. 26 November 2012 (has links)
Experiments were conducted to investigate the punching shear behaviour of thick slabs with identical spans and depths, subjected to monotonic point load conditions. Variables included: reinforcement ratio, column size, and reinforcement size. Analytical studies conducted as part of this thesis indicate that the current CSA A23.3 and the ACI 318 can be unconservative for thick slabs with low reinforcement ratios. The new fib Model Code provisions for punching offer an effective method for determining the full load-rotation behaviour of a slab up to failure, including accurate failure predictions. A summary of the background of current design procedures and standards will be presented, and a comparison between the different design equations and theories will be given. Based on the findings of this project, it is proposed that the provisions accepted by the fib Model Code should be considered for implementation in the CSA and ACI standards.
86

Punching Shear Behaviour of Thick Reinforced Concrete Slabs

Netopilik, Robert J. 26 November 2012 (has links)
Experiments were conducted to investigate the punching shear behaviour of thick slabs with identical spans and depths, subjected to monotonic point load conditions. Variables included: reinforcement ratio, column size, and reinforcement size. Analytical studies conducted as part of this thesis indicate that the current CSA A23.3 and the ACI 318 can be unconservative for thick slabs with low reinforcement ratios. The new fib Model Code provisions for punching offer an effective method for determining the full load-rotation behaviour of a slab up to failure, including accurate failure predictions. A summary of the background of current design procedures and standards will be presented, and a comparison between the different design equations and theories will be given. Based on the findings of this project, it is proposed that the provisions accepted by the fib Model Code should be considered for implementation in the CSA and ACI standards.
87

Distribuce farmářské produkce - bedýnky / Distribution of the Farm Products - Farm Boxes

PRŮŠOVÁ, Mirka January 2016 (has links)
The diploma dissertation deals with farm box home delivery which is world widespread form of an alternative food system. The main aim of this dissertation was to identify the subjects involved in farm box distribution and make a survey on experiences with this form of business - afterwards to define the consumers´ attitude to this way of distribution.
88

The consequences of the culture aspect and the power distance in the execution of global strategies in multinational companies in Brazil

Campos, Robson Pinheiro Rodrigues de 28 October 2015 (has links)
Submitted by Robson Campos (rcampos@uol.com.br) on 2016-02-22T12:19:25Z No. of bitstreams: 1 Master's Thesis_CIM2_RobsonCampos_Final Version_uploaded281215.pdf: 956324 bytes, checksum: efa8185ebe5e8bc92dbd2d369654082e (MD5) / Approved for entry into archive by Janete de Oliveira Feitosa (janete.feitosa@fgv.br) on 2016-02-25T14:14:37Z (GMT) No. of bitstreams: 1 Master's Thesis_CIM2_RobsonCampos_Final Version_uploaded281215.pdf: 956324 bytes, checksum: efa8185ebe5e8bc92dbd2d369654082e (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2016-02-29T12:18:56Z (GMT) No. of bitstreams: 1 Master's Thesis_CIM2_RobsonCampos_Final Version_uploaded281215.pdf: 956324 bytes, checksum: efa8185ebe5e8bc92dbd2d369654082e (MD5) / Made available in DSpace on 2016-02-29T12:19:07Z (GMT). No. of bitstreams: 1 Master's Thesis_CIM2_RobsonCampos_Final Version_uploaded281215.pdf: 956324 bytes, checksum: efa8185ebe5e8bc92dbd2d369654082e (MD5) Previous issue date: 2015-10-28 / One of the challenges presented by the current conjecture in Global Companies is to recognize and understand that the culture and levels in structure of the Power Distance in Organizations in different countries contribute, significantly, toward the failure or success of their strategies. The alignment between the implementation and execution of new strategies for projects intended for the success of the Organization as a whole, rather than as an individual part thereof, is an important step towards reducing the impacts of Power Distance (PDI) on the success of business strategies. A position at odds with this understanding by Companies creates boundaries that increase organizational chasms, also taking into consideration relevant aspects such as, FSAs (Firm-Specific Advantages) and CSAs (Country-Specific Advantages). It is also important that the Organizations based in countries or regions of low Power Distance (PDI) between its individuals be more flexible and prepared to ask and to hear the suggestions from Regional and Local Offices. Thus, the purpose of this study is to highlight the elements of effective strategy implementation considering the relevant aspects at all levels of global corporate culture that justify the influences of power distance when implementing new strategies and also to minimize the impacts of this internal business relationship. This study also recognizes that other corporate and cultural aspects are relevant for the success of business strategies so consider, for instance, the lack of alignment between global and regional/local organizations, the need for competent leadership resources, as well as the challenges that indicate the distance between the hierarchical levels ─ Headquarters and Regional Office ─ as some of the various causes that prevent the successful execution of global strategies. Finally, we show that the execution of the strategy cannot be treated as a construction solely created by the Headquarters or by only one Board and that it needs to be understood as a system aimed at interacting with the surroundings.
89

Mentoring in the HIV/AIDS context : exploring the experiences of befrienders

Tlaka, Thabang Enoch 19 January 2012 (has links)
Mentoring as a process to develop and enhance the functioning of new members in organisations has become prominent in the last two decades. In various disciplines such as law, education and business, the implementation of mentoring processes and concepts have been embraced. With an estimated two-thirds of the population in sub-Saharan Africa living with HIV/AIDS, health care professionals seem to have also embraced the mentoring process and concepts. In this study the experiences of lay counsellors, referred to as Befrienders, in a mentoring programme were explored. In addition, the researcher sought to identify potential challenges that Befrienders experienced in the mentoring programme, how they understood the challenges and how these challenges were addressed. The researcher then explored the potential skills that may have been learned within the mentoring programme. The exploration also produced some ideas on how the mentoring programme could be improved. Furthermore, the study seems to have made a contribution to mentoring theory. In the study, a convenient sample of five formal interviews and two pilot interviews were conducted. The participants consisted of four students, and one staff member from the University of Pretoria. Participants were interviewed for 1½ hours using semi-structured, individual and face-to-face interviews. A thematic analysis was used to interpret the data and social constructionism was used as the theoretical framework to make sense of the findings. In the findings, five prominent themes were identified, namely: (i) Being mentored (Experiencing the programme), (ii) Interpersonal relationships (Experiencing others), (iii) A developing inner world (Experiencing the Self), (iv) Negotiating boundaries (Managing relationships), and (v) Other issues related to HIV/AIDS (Experiencing the context). It was found, among other things, that the Befrienders constructed their own understanding of the mentoring process, that they used the mentoring relationship with their supervisor to understand the clients, and that they developed new perspectives as they learned about themselves. Finally, as a result of being mentored and of the process of development, the Befrienders seemed to have developed a deeper desire to do more work in the HIV/AIDS context. / Dissertation (MA)--University of Pretoria, 2012. / Psychology / unrestricted
90

Performance and Design of Retention Anchors in Blast Resistant Windows

Alameer, Alameer Marai 01 December 2020 (has links)
Windows in building façade are vulnerable to blast pressures. When subjected to blast shock waves, glass windows may suffer failures, potentially causing serious injuries and casualties to the building occupants due to the flying glass shards and other projectiles. Protective films and laminated glass are widely used to protect windows against blast loads. These techniques have proven to reduce or prevent hazards associated with glass breakage. The use of steel or strengthened aluminum frames also reduce window blast hazards associated with frame failures. However, such measures are not always sufficient to mitigate the blast hazard if window retention anchors do not have sufficient resistance to blast pressures. Research on blast resistant windows is scarce in the literature. Therefore, a comprehensive research project was undertaken to address the behaviour, analysis, and design of window retention anchors. The research program consisted of combined experimental and analytical components. Three main phases were pursued, comprising of: i) Experimental research using a shock tube as blast simulator, ii) Numerical investigation based on three-dimensional finite element method (FEM) of analysis, and iii) Non-linear dynamic analysis of window systems based on a single-degree-of-freedom (SDOF) simplification. The experimental phase consisted of tests of 23 punched windows mounted on four different types of substrates consisting of structural steel, reinforced concrete, concrete block masonry, and stone masonry. The experimental parameters included window size and aspect ratio, glazing type, protective film thickness, substrate type, as well as the number and pattern of window retention anchors. Two levels of blast pressure-impulse combinations were used as per the recommendations of the U.S General Services Administration (GSA).The numerical phase involved FEM modelling and analysis of selected test windows. The FEM models were first validated against test results. The validated models were then employed to conduct an analytical parametric study. The parameters in this phase consisted of; substrate type, window frame rigidity, anchor fixity level in the substrate, window aspect ratio and size, anchor spacing, and blast pressure-impulse combination. The results demonstrated the significance of design parameters on window response, while also defining anchor force distribution along the window frame. A simplified SDOF method of analysis was developed for window systems, including the effects of anchor flexibility and substrate rigidity on non-linear response. The analysis approach includes the construction of window resistance functions in pre-break and post-break phases of response, where the latter stage of response is dominated by the membrane action of protective film. The analysis leads to the computation of anchor design forces, which have been validated against anchor shear and axial tension forces recorded experimentally. The SDOF analysis is recommended for use in designing blast-resistant window retention anchors on different substrates.

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