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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.
61

Faceamento de solo grampeado com malhas de aço : estudo dos critérios de dimensionamento / Soil nail facing with steel meshes : design parameters study

Rosa, Bruno Denardin da January 2015 (has links)
O uso de sistemas de faceamento flexíveis com malhas metálicas é uma alternativa viável ao uso do concreto projetado como faceamento em sistemas de solo grampeado. Vários modelos de malhas são empregados hoje para este uso, sendo classificados pela resistência à tração no sentido longitudinal. Mesmo que relevante, segundo Cala et al., (2012), somente este dado é insuficiente para o correto dimensionamento destas soluções. A presente pesquisa busca identificar quais os parâmetros de resistência são necessários para o dimensionamento de um faceamento em malha metálica. Para tanto foram avaliadas duas metodologias desenvolvidas especificamente para as malhas aplicadas junto com a solução de solo grampeado, os métodos Ruvolum e Macro1. Foram então desenvolvidos equipamentos, similares aos utilizados por Roduner (2011) e Cala et al. (2012), para caracterizar 4 diferentes modelos de malhas, avaliando a resistência das mesmas frente aos esforços considerados nos modelos de cálculo investigados, tração e o cisalhamento no contato malha/grampo. Deste modo, foram utilizados resultados de ensaios em escala real com a simulação de um talude em solo tratado com as 4 malhas, para a validação dos métodos de dimensionamento, e para investigar quais os parâmetros de resistência da malha são mais importantes. Como resultado foram determinadas as resistências das malhas avaliadas, sendo a de tração no sentido longitudinal entre 50 e 140 kN, e a resistência no contato malha/grampo, que variou entre 10 e 30 kN. Por fim foi realizada uma análise paramétrica com o método Ruvolum a fim de verificar a influência na variação da coesão, espessura instável e ângulo de atrito, dados nem sempre bem definidos em projeto. Os resultados mostram, como era esperado, a grande sensibilidade da variação nos resultados frente aos efeitos da coesão, sendo então recomendado, como em qualquer análise de estabilidade cautela no uso deste parâmetro. A análise destes resultados permite concluir que o método mais adequado para modelar um talude em solo grampeado com face em tela foi o Ruvolum, com previsões que se aproximaram das medições reais dos ensaios de campo. / The use of flexible facing systems with steel meshes is a viable alternative to the use of shotcrete as facing in soil nailing systems. Currently several different models meshes are being used today for this purpose, being classified only by the tensile strength in the longitudinal direction of the mesh. Even though this parameter is quite relevant, alone it cannot be used to design the flexible facing systems. So this research aims to identify which steel mesh strength parameters are really needed for the correct dimensioning of such solutions. In order to do so two calculation methodologies, specially developed for steel meshes design, were investigated. The design models are called Ruvolum and Macro1 Equipments were developed, similar to those presented in Cala et al. (2012), to investigate four different models of mesh, in order to find the strength parameters presented on the studied calculation models, being than tensile and shear. Thus, to validate the investigated design methodologies, field tests results were compared to the models predictions. As product of the research it was possible to determine the tensile strength of the 4 meshes models, being then ranging from 50 and 140 kN. Also it was possible to define the shear resistance in the nail head/mesh contact, which ranges from 10 to 30 kN. The last step of the research was a parametric analysis, performed with the Ruvolum method to evaluate the influence on the variation of cohesion, unstable thickness and friction angle in the predictions, since this data aren’t always available in ordinary projects. These analysis have showed that the most influent parameter is cohesion, one that is very hard to determine. Also it was found by the results analysis that the appropriate calculation model to simulate a slope stabilized with soil nail and steel meshes facing is the Ruvolum, due the closeness of the predictions to the real field data.
62

Corporate Leverage, Constraints, and Compliance

Alnamlah, Abdullah Khaled 05 August 2019 (has links)
The first chapter evaluates the zero-leverage effect on firms' financial constraints. Moreover, using investment- and cash-to-cash-flow sensitivities as financial constraint indicators, the results suggest that unleveraged firms are expected to face lower constraints relative to leveraged firms. Lastly, the results indicate that the zero-leverage effect on firms’ financial constraints is more likely stronger for smaller firms, zero-dividend firms, firms with lower proportions of tangible assets, and growth firms. The second chapter develops a new quantitative measure that reflects the extent to which a firm complies to Shariah relative to the other firms located in a certain region at a certain time. This measure can be customized to be consistent with each investor’s objectives, constraints, and beliefs. We argue that the use of this measure is preferable to the existing use of ratio thresholds for the following two reasons. First, it is more Shariah-appropriate because it provides the Shariah-compliant investor with a clear understanding of the relative compliance status of each firm he wishes to invest in. Second, it can be incorporated into any portfolio optimization model to create a balance between improving Shariah compliance and not compromising investment returns.
63

Preserve, renew, invent [Light Bytes]: an art exploration into disseminating aphorisms

Kaiser, Lesley January 2008 (has links)
The expanding potential for the dissemination and archiving of aphorisms is explored in this practice-based research thesis. An aphorism is a short statement that communicates an insight about the world (and can sometimes function as a guide to action). Eric McLuhan, interviewed in Signs of the Times: The History of Writing (Goëss Video, 1996), suggests that the future of the book is the aphoristic statement. Aphoristic knowledge has traditionally been transmitted through texts and through libraries, but this project brings into play various modes of recirculating aphoristic texts using contemporary distribution networks and digital media such as moving image, projection on to urban screens, artists’ books, archival digital photography and glazed ceramics. Texts ‘virally inhabit’ a number of sites and languages in a series of works situated in the interdisciplinary context of contemporary text art and artists’ books. The sayings rejoin the cultural river of ideas in local and international incarnations. Practice-based work (80%) and exegesis (20%)
64

The theory and technology of early colour photographic processes including antipdean heliochromes housed in the Australian War Memorial

Nizette, Mark, n/a January 1983 (has links)
n/a
65

High-Throughput Screening for Novel Anti-cancer Radiosensitizers for Head and Neck Cancer

Ito, Emma 18 January 2012 (has links)
Despite advances in therapeutic options for head and neck cancer (HNC), treatment-associated toxicities and overall clinical outcomes have remained disappointing. Even with radiation therapy (RT), which remains the primary curative modality for HNC, the most effective regimens achieve local control rates of 45-55%, with disease-free survival rates of only 30-40%. Thus, the development of novel strategies to enhance tumor cell killing, while minimizing damage to the surrounding normal tissues, is critical for improving cure rates with RT. Accordingly, we sought to identify novel radiosensitizing therapies for HNC, exploiting a high-throughput screening (HTS) approach. Initially, a cell-based phenotype-driven HTS of ~2,000 commercially available natural products was conducted, utilizing the short-term MTS cell viability assay. Cetrimonium bromide (CTAB) was identified as a novel anti-cancer agent, exhibiting in vitro and in vivo efficacy against several HNC models, with minimal effects on normal fibroblasts. Two major limitations of our findings, however, were that CTAB did not synergize with radiation, nor was its precise cellular target(s) elucidated. Consequently, an alternative strategy was proposed involving a target-driven RNAi-based HTS. Since the colony formation assay (CFA) is the gold standard for measuring cellular effects of radiation in vitro, an automated high-throughput colony-formation read-out was developed as a more appropriate end-point for radiosensitivity. Although successful as a tool for the discovery of potent anti-cancer cytotoxics, a technical drawback was its limited dynamic range. Thus, the BrdU incorporation assay, which measures replicative DNA synthesis and is a viable CFA alternative, was employed. From an RNAi-based screen of ~7000 human genes, uroporphyrinogen decarboxylase (UROD), a key regulator of heme biosynthesis, was identified as a novel tumor-selective radiosensitizing target against HNC in vitro and in vivo. Radiosensitization appeared to be mediated via tumor-selective enhancement of oxidative stress from perturbation of iron homeostasis and increased ROS production. UROD was significantly over-expressed in HNC patient biopsies, wherein lower pre-RT UROD levels correlated with improved disease-free survival, suggesting that UROD expression could also be a potential predictor for radiation response. Thus, employing a HTS approach, this thesis identified two novel therapeutic strategies with clinical potential in the management of HNC.
66

High-Throughput Screening for Novel Anti-cancer Radiosensitizers for Head and Neck Cancer

Ito, Emma 18 January 2012 (has links)
Despite advances in therapeutic options for head and neck cancer (HNC), treatment-associated toxicities and overall clinical outcomes have remained disappointing. Even with radiation therapy (RT), which remains the primary curative modality for HNC, the most effective regimens achieve local control rates of 45-55%, with disease-free survival rates of only 30-40%. Thus, the development of novel strategies to enhance tumor cell killing, while minimizing damage to the surrounding normal tissues, is critical for improving cure rates with RT. Accordingly, we sought to identify novel radiosensitizing therapies for HNC, exploiting a high-throughput screening (HTS) approach. Initially, a cell-based phenotype-driven HTS of ~2,000 commercially available natural products was conducted, utilizing the short-term MTS cell viability assay. Cetrimonium bromide (CTAB) was identified as a novel anti-cancer agent, exhibiting in vitro and in vivo efficacy against several HNC models, with minimal effects on normal fibroblasts. Two major limitations of our findings, however, were that CTAB did not synergize with radiation, nor was its precise cellular target(s) elucidated. Consequently, an alternative strategy was proposed involving a target-driven RNAi-based HTS. Since the colony formation assay (CFA) is the gold standard for measuring cellular effects of radiation in vitro, an automated high-throughput colony-formation read-out was developed as a more appropriate end-point for radiosensitivity. Although successful as a tool for the discovery of potent anti-cancer cytotoxics, a technical drawback was its limited dynamic range. Thus, the BrdU incorporation assay, which measures replicative DNA synthesis and is a viable CFA alternative, was employed. From an RNAi-based screen of ~7000 human genes, uroporphyrinogen decarboxylase (UROD), a key regulator of heme biosynthesis, was identified as a novel tumor-selective radiosensitizing target against HNC in vitro and in vivo. Radiosensitization appeared to be mediated via tumor-selective enhancement of oxidative stress from perturbation of iron homeostasis and increased ROS production. UROD was significantly over-expressed in HNC patient biopsies, wherein lower pre-RT UROD levels correlated with improved disease-free survival, suggesting that UROD expression could also be a potential predictor for radiation response. Thus, employing a HTS approach, this thesis identified two novel therapeutic strategies with clinical potential in the management of HNC.
67

Revealing and Concealing Hitler's Visual Discourse: Considering "Forbidden" Images with Rhetorics of Display

Donald, Matthew G 20 August 2012 (has links)
Typically, when considering Adolf Hitler, we see him in one of two ways: A parodied figure or a monolithic figure of power. I argue that instead of only viewing images of Hitler he wanted us to see, we should expand our view and overall consideration of images he did not want his audiences to bear witness. By examining a collection of photographs that Hitler censored from his audiences, I question what remains hidden about Hitler’s image when we are constantly shown widely circulated images of Hitler. To satisfy this inquiry, I utilize rhetorics of display to argue that when we analyze and include these hidden images into the Hitlerian visual discourse, we further complicate and disrupt the Hitler Myth. This study aims to contribute to recent scholarship that aims to learn more about the “hidden” Hitler as well as to rhetorical studies of display.
68

Designing for diverse users - a case study on touchscreen smartphone customization

Haberman, Vicki 03 April 2012 (has links)
The touchscreen smartphone platform is inherently flexible, giving it the potential to meet the needs and desires of individuals diverse in age and ability. Despite universal design research efforts providing industry with guidance to address this opportunity, current designs fall short. The disconnect stems from differing priorities in design and development and opposing approaches to defining and grouping the user population. The research presented in this dissertation aims to remove these issues from the process of discovering touchscreen smartphone design opportunities. It focuses on users' prior and desired customizations rather than ability- or market-factors. Data were collected on participants' devices' out-of-the-box, current and desired device states along with related stories about their actual and desired device modifications. Template and image analyses identified patterns in the data, which also revealed an underlying structure for organizing and presenting participants' needs and desires associated with smartphone touchscreen customizations. The needs and desires suggest opportunities for industry to shift towards universal design. The structure offers an approach to addressing the gaps between the ability-centered and market-driven approaches to the design of consumer technology.
69

Methods to achieve wavelength selectivity in infrared microbolometers and reduced thermal mass microbolometers

Jung, Joo-Yun, 1976- 02 February 2011 (has links)
The use of a patterned resistive sheet as an infrared-selective absorber, including the effects of a mechanical support dielectric layer is discussed. Also, modified dielectric coated Salisbury Screen can improve both the wavelength selectivity and the speed of thermal response for microbolometers. These patterned resistive sheets and Modified dielectric coated Salisbury Screen are a modified form of classical Salisbury Screens that utilize a resistive absorber layer placed a quarter-wavelength in front of a mirror. These structures can show a narrower detection bandwidth when compared to conventional microbolometers. For a Modified dielectric coated Salisbury Screen for multi-spectral system, wavelength selectivity can be varied by changing the distance to the mirror, and for patterned resistive sheet, wavelength selectivity can be varied by changing the lithographically drawn parameters of the array. Hence, different pixels in a focal plane array can be designed to produce a “multi-color” infrared imaging system. Also, the thermal mass of microbolometer is reduced using patterned resistive structure. / text
70

Lietuvos geležinkelių poveikio žmonių gyvenimo kokybei tyrimas / The Research of the Effect of Lithuania Railway Transport on Human Life Quality

Savickaitė, Kristina 19 June 2012 (has links)
Šiame baigiamajame bakalauro darbe atlikta geležinkelių transporto vystymosi raidos literatūrinė apžvalga, kuri parodo, kad Lietuvos geležinkelių transportas buvo ir yra svarbi visuomenės gyvenimo dalis, be kurios nebūtų plėtojama ekonomika ir kitos veiklos sritys. Tačiau išanalizavus aplinkosauginius aspektus, paaiškėja, kad geležinkelio transportas - triukšmo šaltinis. Šis traukinių keliamas triukšmas yra ypač svarbus gyvenimo kokybės rodiklis. Išanalizuota geležinkelių transporto eksploatacijos metu pasireiškiantys kenksmingi veiksniai, bei jų poveikis žmonių sveikatai ir gyvenimo kokybei. Atlikta Mažeikių miesto gyventojų apklausa. Įvertinta dabartinė situacija. Išanalizavus apklausos rezultatus, padarytos išvados ir pateikti geriausi triukšmo mažinimo būdai, kaip apsaugoti gyventojus, išvengiant triukšmo padarinių. Atlikti akustinių ekranų efektyvumo matavimai, šalia Šniūraičių gyvenvietės, kurie parodė, kad siekiant komforto žmonių kasdieniniame gyvenime būtina imtis priemonių kovojant su aplinkos fizikine tarša. Pateikti pasiūlymai ir rekomendacijos šiai problemai spręsti. / Literary review of railway transport development is carried out in this bachelor’s paper, which shows that Lithuanian railway transport has always been an important part of public life, helping to develop economics and other areas of activities. However, analysis of environmental issues shows that the railway transport is the noise source. The train-caused noise is an especially important index of life quality. Harmful factors arising during railroad transport exploitation are analysed as well as their impact upon human health and life quality. Mažeikiai town residents were interviewed. Current situation was assessed. Survey results were analysed, conclusions made, the best ways to reduce noise in order to protect the residents from noise consequences were suggested. Carry out performance measurements of acoustic screens, Šniūraičiai near the village. Noise measurement findings showed that in order to reach comfort in everyday life measures have to be taken to reduce physical pollution of the environment. Suggestions and recommendations to solve the problem are given.

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