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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.
261

En jämförande studie mellan spikningsplåtsförband och WT-Tskruvar i limträkonstruktioner / A comparing study between nailing plates-joints and WT-T screws in gluelam constructions

Ericsson, Joel, Rusimovic, Goran January 2006 (has links)
Detta examensarbete har gjorts på uppdrag av Skanska Teknik med handledning av Johan Sjödin. Arbetets syfte var att jämföra olika limträförband, utförda av antingen spikningsplåtar eller WT-T skruvar, och komma fram till den bästa lösningen med hänsyn till bärförmåga, kostnad och utförandetid. I ett projekt har de spikningsplåtar, som används vid limträförband, börjat rosta under extremt fuktiga förhållanden fastän spikningsplåtarna är rostfria enligt tillverkaren. En fördel med WT-T skruvar är att de är gömda inne i träet och på så sätt inte i direkt kontakt med den aggressiva miljön, men även skyddad mot brand. Andra fördelar med WT-T är att utförandetiden är kort och kostnaden är lägre än spikningsplåtsalternativet. Ett experiment har gjorts för att undersöka hur träet med inborrade WT-T skruvar beter sig under uttorkning. / This diploma work was made under commission by Skanska Teknik, with guidance by Johan Sjödin. The purpose of this work was to compare different gluelam joints, performed by nailing plates or WT-T screws, and find out the best solution with regard to carrying ability, cost and performance time. In a certain project have the nailing plates, which are used in gluelam joints, corroded under extremely damp circumstances although the nailing plates are rust free according to the manufacturer. An advantage with WT-T screws is that they are hidden inside of the tree and in that way not in directly contact with the aggressive environment, but also protected against fire. The other advantages with WT-T screws are that the performance time is short and the cost is lower than the nailing plates-alternative. An experiment has been carried out to investigate how the tree with WT-T screws behaves itself during drying period.
262

En jämförande studie mellan spikningsplåtsförband och WT-Tskruvar i limträkonstruktioner / A comparing study between nailing plates-joints and WT-T screws in gluelam constructions

Ericsson, Joel, Rusimovic, Goran January 2006 (has links)
<p>Detta examensarbete har gjorts på uppdrag av Skanska Teknik med handledning av Johan Sjödin. Arbetets syfte var att jämföra olika limträförband, utförda av antingen spikningsplåtar eller WT-T skruvar, och komma fram till den bästa lösningen med hänsyn till bärförmåga, kostnad och utförandetid. I ett projekt har de spikningsplåtar, som används vid limträförband, börjat rosta under extremt fuktiga förhållanden fastän spikningsplåtarna är rostfria enligt tillverkaren. En fördel med WT-T skruvar är att de är gömda inne i träet och på så sätt inte i direkt kontakt med den aggressiva miljön, men även skyddad mot brand. Andra fördelar med WT-T är att utförandetiden är kort och kostnaden är lägre än spikningsplåtsalternativet. Ett experiment har gjorts för att undersöka hur träet med inborrade WT-T skruvar beter sig under uttorkning.</p> / <p>This diploma work was made under commission by Skanska Teknik, with guidance by Johan Sjödin. The purpose of this work was to compare different gluelam joints, performed by nailing plates or WT-T screws, and find out the best solution with regard to carrying ability, cost and performance time. In a certain project have the nailing plates, which are used in gluelam joints, corroded under extremely damp circumstances although the nailing plates are rust free according to the manufacturer. An advantage with WT-T screws is that they are hidden inside of the tree and in that way not in directly contact with the aggressive environment, but also protected against fire. The other advantages with WT-T screws are that the performance time is short and the cost is lower than the nailing plates-alternative. An experiment has been carried out to investigate how the tree with WT-T screws behaves itself during drying period.</p>
263

Effects of Brush to Grass Conversion on the Hydrology and Erosion of a Semiarid Southwestern Rangeland Watershed

Simanton, J. R., Osborn, H. B., Renard, K. G. 16 April 1977 (has links)
From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Increased nutritional and economic demands for agricultural products have dictated the need for greater and more efficient use of western grass forage. Vegetation manipulation is the quickest and most economical means of increasing forage. However , the hydrologic effects must be taken into consideration before embarking on a large scale vegetation manipulated program. This study discusses the hydrologic and erosion changes measured from a 110-acre semiarid watershed which was converted from brush to grass by root plowing and seeding. Significant changes were observed in rainfall-runoff relationships as average summer runoff was considerably in excess of predictions. Sediment yield also varied, and both of these results were tied to the change in vegetative cover and post conversion rainfall conditions.
264

The social sustainability of the Table Mountain cableway

Deysel, Valencia 08 May 2014 (has links)
Social sustainability provides a meaningful approach for industry practitioners wishing to establish a platform to engage communities within enterprise development. It can be said that sustainability requires much more than environmental and fiscal achievements and, with an increased awareness of issues such as equity and power sharing, more corporates are incorporating their strategies in line with social responsibility values. This study therefore takes a closer look at how the Table Mountain Aerial Cableway Company, integrates this important concept of social sustainability in its business practices. The tourism industry has in fact grown to such an extent that global economists estimate the progress of international growth at between three and six percent annually. However, this growth can only be measured when businesses take social responsibility factors into consideration. According to the UNWTO (2011, p 1) UN Secretary-General, Ban Ki-Moon, opened the Fourth UN Conference on Least Developed Countries stating that the majority of: “…least developed countries (LDCs) are rich in resources. All have young and vibrant populations. These men and women need decent jobs, education, training, so they can make the most of their country’s assets - minerals and other commodities, farmland, rich stores of biodiversity and tourism potential”. This study therefore focuses on current and future issues pertaining to socially sustainable tourism at the Table Mountain Aerial Cableway Company in Cape Town, South Africa. In addition, it presents solutions for reducing the negative impacts of tourism, whilst at the same time embracing the benefits of tourism for the area and its local communities. The outcome of the study found that the Table Mountain Aerial Cableway Company added little value to social responsibility objectives. The company has made a significant effort in marketing their product through the mass media. However, there is an overall corporate responsibility barrier. Much still needs to be done to ensure accountability for social responsibility issues, not just within this particular company, but also throughout the tourism industry. / Environmental Sciences / M. Sc. (Environmental Science)
265

Responsabilité sociétale : quelles contributions des entreprises à la conservation de la biodiversité ? / CORPORATE SOCIAL RESPONSIBILITY : WHICH CONTRIBUTION TO BIODIVERSITY CONSERVATION?

Wolff, Anastasia 01 December 2017 (has links)
Alors que nous faisons face à une crise biologique majeure, acteurs institutionnel et ONGs exhortent les entreprises à s’engager pour enrayer cette érosion écologique. L’objectif de la thèse est d’analyser, évaluer et faire évoluer la contribution potentielle des entreprises à la conservation de la biodiversité dans le cadre de leur responsabilité sociétale (RSE).Un cadre d’analyse est développé pour évaluer la prise en charge par une entreprise de ses responsabilités écologiques en termes de moyens – les initiatives RSE a priori favorables à la biodiversité mises en œuvre – et de résultats – la compatibilité des activités de l’entreprise avec la conservation de la biodiversité. Après avoir caractérisé les initiatives RSE à partir de l’étude d’engagements d’entreprises endossés comme contributions à la Stratégie nationale pour la biodiversité, une méthode est proposée pour détecter si les activités d’une entreprise sont écologiquement non-durables. Le postulat est que le respect des capacités de charge des écosystèmes est un prérequis à la conservation effective de la biodiversité. Cette méthode, adaptée de l’évaluation environnementale absolue de la durabilité, est appliquée, dans le cadre de deux projets de recherche-intervention, au portfolio alimentaire du Groupe Casino et au cycle de vie de deux installations de stockage de déchets dangereux de SARP Industries. Des orientations stratégiques visant à éviter-réduire-compenser les pressions non durables sont proposées. Soulignant l’importance de renforcer la prise en charge des pressions étendues, cette thèse ouvre plus largement des perspectives pour les secteurs d’activité et les politiques publiques. / As we are experiencing a major biological crisis, institutional actors and NGOs are calling on businesses to engage efforts aiming at halting biodiversity loss. The objective of the thesis is to analyze and evaluate the potential contribution of corporate social responsibility (CSR) to biodiversity conservation.A framework is developed to analyze to which extent a company takes in charge its ecological responsibilities. After characterizing CSR initiatives based on the case study of business commitments to contribute to the French National Biodiversity Strategy, a method is proposed to test whether business activities exert unsustainable pressures on ecosystems. It is assumed that compatibility with ecosystems’ carrying capacities is a prerequisite for effective biodiversity conservation. This method, adapted from the “absolute environmental sustainability assessment” (AESA) approach, is applied in the context of research-intervention projects to the food portfolio of the mass-market retailer Groupe Casino and to the life cycle of two facilities of SARP Industrie specialized in the disposal and storage of hazardous waste. The comparison of the company’s environmental footprints with the ecological constraints is used to draw a comprehensive strategy based on the mitigation hierarchy. As our results highlight the opportunity to strengthen the management of extended pressures through CSR, possible implications for sectors and public policies are discussed.
266

Fatigue crack propagation in AA 7050-T7451 alloy considering environment, stress ratio, rolling direction and waveform effects / Propagação de trinca por fadiga na liga AA7050-T7451 considerando o efeito do meio ambiente, razão de tensões, direção de laminação e forma de onda

José Fernando Cárdenas Barbosa 17 March 2017 (has links)
Main extrinsic and intrinsic modifiers factors of crack growth rate in AA7050-T7451 were assessed in order to provide tools for aeronautical structures designers. These tools cover most necessary information to project aircraft\'s structures using the studied alloy, under damage tolerance philosophy. The experimental methodology consisted of use CT specimens, on TL and LT rolling direction to test its behavior under different conditions of stress ratio, force waveform, and the environment. The stress ratio values were 0.1 and 0.5, the force waveform used were sine and trapezoidal or Dwell under normal air laboratory conditions and salt fog 3.5%NaCl weight in order to simulate the marine environment. In Dwell tests, results were checked with the electrical potential drop technique (DCPD) in addition to the crack opening displacement (COD) method. Using the Walker coefficients, calculated on the present research, could be projected accurately the crack propagation behavior on Paris region and do fatigue life predictions using da/dN and S-N diagrams for different stress ratio values. The corrosion environment increases both crack growth rate and &Delta;Kth due to oxides formation on the crack path that generates a crack closure effect. Dwell carrying makes decrease the crack growth rate by decreasing the slope of the Paris line on log (da/dN) versus log (&Delta;K) curve, instead of shifting down the line as occurs on titanium alloys. Rolling direction change from LT to TL increase the FCG rate in both threshold and Paris region, where the rate change use to be small. / Os principais fatores modificadores extrínsecos e intrínsecos da taxa de propagação de trincas na liga AA7050-T7451 foram avaliados para fornecer subsídios para projetistas de estruturas aeronáuticas, com base na filosofía de tolerância ao dano. A metodologia experimental consistiu em ensaiar corpos de prova do tipo compact tension (CT) da liga nas direções de laminação TL e LT, para verificar seu comportamento sob diferentes razões de tensões, forma de onda e condição ambiente. Os valores de razão de tensão estudados foram 0,1 e 0,5, as formas de onda foram senoidal e trapezoidal ou de Dwell, em condições normais de laboratório, ao ar, e névoa salina 3,5% NaCl, em massa, para simular um ambiente marinho. No caso dos ensaios Dwell, os resultados foram conferidos pelo método de queda de potencial eléctrico (QPE), além do método de flexibilidade elástica. Usando os coeficientes de Walker calculados a partir dos resultados obtidos, pôde-se projetar com precisão o comportamento da propagação de trinca na região de Paris e prever a vida em fadiga usando os diagramas da/dN e S-N para diferentes valores da razão de tensões. O ambiente corrosivo aumenta tanto a taxa de propagação de trinca, quanto o valor de &Delta;Kth por causa da formação de óxidos na trajetória da trinca, que geram um efeito de fechamento sobre a mesma. Quanto à forma de onda, verificou-se que o carregamento Dwell diminui a taxa de propagação de trinca, diminuindo a inclinação das curvas log (da/dN) versus log (&Delta;K) na região de Paris, ao invés de deslocá-la paralelamente como ocorre com ligas de titânio. A mudança da direção de laminação de LT para TL aumenta a taxa de propagação de trinca por fadiga (PTF) tanto na região de threshold, quanto na região de Paris, onde a mudança de taxa é pequena.
267

Behavioural-ecology of the white rhinoceros (Ceratotherium simum) in the Willem Pretorius Game Reserve

Jordaan, Hermanus Lukas 06 1900 (has links)
The main aim of this study was to classify and describe the plant communities in the home range of white rhinoceros in order to understand the animal seasonal foraging ecology. To provide a detailed habitat description, forty sample plots were stratified randomly. A TWINSPAN classification, refined by Braun-Blanquet procedures, was carried out on the Viewpoint section of the reserve. Ten plant communities, grouped into five major community types, were identified. The veld condition and ecological carrying capacity in these communities were measured, stating an abundance of food on long grass while the short grass equal the number of short grass feeders. A number of behavioural aspects such as activity data, home range utilization and dietary usage were examined. Statistical methods such as the Spearman rank-order correlation, Wilcoxon sign test and Student T-test were used on rhino data. The difference in usage of the home range during wet and dry seasons was insignificant. / Environmental Sciences / M.Sc. (Environmental Management)
268

Letištní terminál / Airport Terminal

Pospíšilová, Vendula January 2019 (has links)
The diploma thesis is focused on a proposal and review of load-carrying steel structure of the airport terminal. The object is located in Zlín. It is a building of a rectangular plan with a ground plan dimensions of 75.0 x 54.0 m. The hall contains 10 main frames spaced by 6.0 m. The total height of the object is variable from 11.5 m to 19.9 m. The part of the construction is composite steel – concrete floor structure with a ground plan dimensions of 75.0 m x 27.0 m. The spatial rigidity of the construction is obtain by bracing. The cladding of the roof and the side walls is designed by sendwich panels, the cladding of the face walls is made by the glass facade system.
269

Výpočet zatížení elektrického pohonu brány / Calculation of load on the electric drive of the gate

Randa, Daniel January 2020 (has links)
This thesis deals with the construction of drives for self-supporting gates. The main parts from which the drive is folded are not discussed here. In addition, the main points of load are solved which arise on the self-supporting gate and it´s contact with the guiding, carrying carts and movement elements. And here is explained what needs to be taken care of by the drive to accommodate the loads, which all aggravate the movement of the structure. in the work are also presented the load types of load calculations by which the drive parameters can be checked for suitability for the application.
270

Objekt pro sportovní účely / Building for sport purposes

Navrátil, Petr January 2013 (has links)
The theme of this diploma thesis is design and check load-carrying steel structure of building for sport purposes in two variants. Building is situated in Holešov town. Primary emphasis is placed on purpose of this building and on her integration to the given locality. The steel structure is created by two objels, main (hall) and side part (admin. part). Both of this building have common east wall. Plan dimension of hall part is 40 on 40m and the highest point of this part is 15,9m height above ground. Admin. part is greated like frame with columns in 8x8m grid and 8m height. Overall height of this part is 8m. For analisys of internal forces was constructed spatial bar model which was used for an optimization of partial bars for both limit states. The cladding will be made by system of Kingspan panels.

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