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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.
431

Creating customer value : A case study at Stilexo

Gustafsson, Marcus, Elg, David January 2008 (has links)
<p>The competition between organizations has become tougher due to the globalization of the market place. This case study has been conducted at Stilexo, which are situated in Skillingaryd. Stilexo is an aluminum die caster and is a part of the Alteams group. Within the Swedish market approximately half of the casted products used are imported and this is a trend that seems to be increasing. In order to stay competitive next to the foreign suppliers the Swedish manufactures needs to differentiate, the question is how? In order to find the answer to the question Thomke and Hippel (2002) argues that the suppliers must listen to their customer with the intention of finding the needs and wants of the customers.</p><p>The purpose of this thesis is to interpret how Stilexo can create higher customer value.</p><p>This thesis has been written with an interpretivistiv research position combined with an inductive approach. The research strategy used is a single case study strategy. A qualitative approach has been used with in-depth interviews of employees at Stilexo and of existing/potential customers to them.</p><p>Price, quality and the ability to deliver on time are parameters that</p><p>have to be fulfilled in order for a supplier to be qualified. If these parameters are reached there are other values that can make a supplier an order winner. The main finding is that the relationship between the supplier and the customer is very vital. A higher interaction between the two parties has the potential of increasing the customer value. Co-creation of new products is something that is mentioned as value adding that can be gained from higher interaction. Further on innovativeness, flexibility, technology, and that the supplier can handle the whole supply chain has also been identified as value adding activities.</p>
432

The influence of Mn on the microstructure and mechanical properties of Al-Si based alloys containing Fe

Lindrud, Lennart, Lindgren, Göran January 2006 (has links)
<p>Abstract</p><p>The purpose of this research is to investigate the influence of Manganese (Mn) on cast aluminum alloys where a substantial amount of Iron (Fe) is included. Ductility and tensile strength need to be improved in recycled aluminum alloys where greater amounts of Fe are found. Fe is a common impurity and is known to be detrimental to mechanical properties and in order to neutralize the effects of Fe; modifiers such as Mn are added. In this investigation, attempts will be carried out aiming to find the optimal amount of Mn. Other related topics that will be discussed are whether there exists a Mn/Fe ratio which clearly modifies the harmful iron- rich phases and improves the properties for a certain alloy or not. Also, will the heat treatment have a significant effect on mechanical properties? These are some of the questions that will be answered in this paper.</p><p>It is hard to find research articles that focus only on the influence of Mn on the microstructure and mechanical properties of Al-Si cast alloys. Much of the work that is already published concerns only a specific alloy and casting method. In this work three different casting processes, sand-, die- and high pressure die-casting, will be simulated by using gradient solidification equipment. Furthermore, the influence of heat treatment on the mechanical properties will be examined.</p><p>The results showed that the solidification rate had the biggest impact on the microstructure and mechanical properties of the alloys, where the fastest cooling rate gave the best results. The effect of Mn seems to influence the samples with coarser microstructures significantly where it had time to modify the Iron-rich needles, also called the β-phase. At higher cooling rates the impact of Mn was impeded. It has been observed that a high content of Mn (around 0.6%) needs to be added before the properties start to improve. UTS (Ultimate Tensile Strength) and YS (Yield Strength) are improved while ductility is lowered. Heat treatment did not seem to have any influence on the effects of Mn.</p>
433

Modeling of magnetohydrodynamic turbulence

Widlund, Ola January 2000 (has links)
<p>Conventional one-point turbulence closures have beenextended with an additional transported scalar for modeling ofmagnetohydrodynamic (MHD) turbulence. The new scalar, α ,captures the length scale anisotropy and tendency towardstwo-dimensionality, which is characteristic feature of MHDturbulence, and allows accurate modeling of the Jouledissipation of turbulence. The concept has been used for both afull Reynolds stress closure, and a three-equation<i>K-ε -α</i>model. An exact transport equation forαwas derived from the governing equations. All terms inthe equation require modeling, however. The proposed modeltransport equation for α includes terms for magneticdissipation, nonlinear energy transfer, and effects of meanshear and strain. Modeling of the magnetic and strain-relatedterms was based on rapid distortion analysis of the linearizedequations, while modeling of nonlinear effects isphenomenological in nature. For homogeneous turbulence, themodel was compared with linear theory, direct numericalsimulations and experiments. For turbulence subjected to astrong magnetic field, the model reproduces the energy andlength scale evolution predicted by linear theory. Whennonlinear effects are of importance, it predicts energy decayand length scale evolution in agreement with experiments. Theeddy viscosity and Reynolds stress versions of the modelcoincide with the respective conventional models in the absenceof a magnetic field. The objective of this project has been todevelop efficient MHD turbulence models for engineeringapplications, especially for modeling of continuous steelcasting. The novel MHD turbulence models appear to benumerically robust, and they have been implemented in acommercial flow solver, together with electromagnetic equationsfor the Lorentz forces in the mean momentum equations.</p><p><b>Keywords:</b>Turbulence model, magnetohydrodynamics, MHD,magnetohydrodynamic turbulence, computational fluid dynamics,continuous casting, dimensionality, Reynolds stresses, eddyviscosity</p>
434

Linear expansion of dental stone after its final set and beyond two hours

Cid Galano, Marcos. January 2003 (has links)
Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains viii, 43 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 41-42).
435

Al-Si Cast Alloys - Microstructure and Mechanical Properties at Ambient and Elevated Temperature

Zamani, Mohammadreza January 2015 (has links)
Aluminium alloys with Si as the major alloying element form a class of material providing the most significant part of all casting manufactured materials. These alloys have a wide range of applications in the automotive and aerospace industries due to an excellent combination of castability and mechanical properties, as well as good corrosion resistance and wear resistivity. Additions of minor alloying elements such as Cu and Mg improve the mechanical properties and make the alloy responsive to heat treatment. The aim of this work is studying the role of size and morphology of microstructural constituents (e.g SDAS, Si-particles and intermetalics) on mechanical properties of Al-Si based casting alloy at room temperatures up to 500 ºC. The cooling rate controls the secondary dendrite arm spacing (SDAS), size and distribution of secondary phases. As SDAS becomes smaller, porosity and second phase constituents are dispersed more finely and evenly. This refinement of the microstructure leads to substantial improvement in tensile properties (e.g. Rm and εF). Addition of about 280 ppm Sr to EN AC- 46000 alloy yields fully modified Si-particles (from coarse plates to fine fibres) regardless of the cooling conditions. Depression in eutectic growth temperature as a result of Sr addition was found to be strongly correlated to the level of modification irrespective of coarseness of microstructure. Modification treatment can improve elongation to failure to a great extent as long as the intermetallic compounds are refined in size. Above 300 ºC, tensile strength, Rp0.2 and Rm, of EN AC-46000 alloys are dramatically degraded while the ductility was increased. The fine microstructure (SDAS 10 μm) has superior Rm and ductility compared to the coarse microstructure (SDAS 25 μm) at all test temperature (from room to 500 ºC). Concentration of solutes (e.g. Cu and Mg) in the dendrites increases at 300 ºC and above where Rp0.2 monotonically decreased. The brittleness of the alloy below 300 ºC was related to accumulation of a high volume fraction damaged particles such as Cu- Fe-bearing phases and Si-particles. The initiation rate of damage in the coarse particles was significantly higher, which enhances the probability of failure and decreasing both Rm and εF compared to the fine microstructure. A physically-based model was adapted, improved and validated in order to predict the flow stress behaviour of EN AC- 46000 cast alloys at room temperature up to 400 ºC for various microstructures. The temperature dependant variables of the model were quite well correlated to the underlying physics of the material
436

Formation of nanocoatings by laser-assisted spray pyrolysis and laser ablation on 2d gold nanotemplates

Dedigamuwa, Gayan S 01 June 2005 (has links)
This thesis describes a new Laser-Assisted Spray Pyrolysis technique developed to grow nanoparticle coatings with controllable particle sizes. In this method, droplets of a precursor formed by a nebulizer are injected into a growth chamber using SF6 carrier gas. An experimental study and a computational model to investigate the particle size dependence on various growth parameters have been carried out. The results show that heating of 1.5and#61549;m droplets of metalorganic precursor in a carrier gas using a CO2 laser resulted in the formation of TiC and Fe3O4 particles with diameters in the range of 50-60nm. Also the results show that by reducing the concentration of the metal organic precursor the diameter of the deposited particles can be reduced.
437

Digital representation and constructability of minimal surfaces in concrete

Keskin, Zeynep 21 September 2015 (has links)
This thesis investigates minimal surfaces in design and researches their potential for constructability in concrete through the creation of physical prototypes with the design of two mold making processes, one being sacrificial and the other reusable. The study starts by acknowledging that minimal surfaces have been extensively explored in the field of differential geometry for decades. In spite of the availability of geometric definitions which provide the basic background for digital model generation (which in this text is assumed to be equal to design itself), minimal surfaces inspired very few people in their architectural design. This study attempts to look into the wider implications of minimal surfaces for architecture by taking up the challenge of designing and realizing various processes of mold making for the fabrication of such surfaces in concrete. Throughout this study, a gradient of complexity in the definition and digital modeling of minimal surfaces will be included as well as a variety of production methods in a research and fabrication based process, in order to investigate the correlation between what can be designed and what can be produced. I shall begin with a historical survey of the constructability of surfaces in thin shell concrete to provide background information for the reader. This chapter on the evolution of concrete structures presents a compilation of selected projects to illustrate the progress of thin shell construction throughout the history of architecture. It is here that I review what happened, why, and who made it possible. I draw heavily on published scholarly studies as most of the selected projects are cornerstones of the evolution of architecture and have been discussed by many others. Here, I simply attempt to remind the reader of the achievements of these projects in order to justify why investigation of the constructability of minimal surfaces may be the next step in the evolutionary process. After this section, the mathematics of surfaces in the complex plane is discussed based on information retrieved from many excellent resources. Here, the intention is to acquire information related to descriptions of various minimal surface types in differential geometry in order to be able to generate their representations in the digital environment. It would have been impossible to generate digital representations of minimal surfaces without the knowledge acquired through these descriptions. The last section provides a comparison of ruled surfaces and minimal surfaces meant to reveal the similarities and differences of such surfaces with regard to the principles of digital representation and fabrication. It provides insight into various fabrication techniques and materials to illuminate the design of a making process in which the goal is to know and control every parameter regarding both the design and fabrication of an object. The discussion of the design of a making process for a complexly shaped object provided in this part is followed by discussion of casting prototypes in concrete. In that section, the subject matter is the design and testing of various mold making techniques for the production of concrete prototypes of a selected minimal surface geometry. This section presents an increasing complexity of mold making from a sacrificial mold to a reusable mold.
438

Colorblind TV : primetime politics of race in television casting

Warner, Kristen Jamaya 07 December 2010 (has links)
Colorblind TV: Primetime Politics of Race in Television Casting posits that in our current racially colorblind society, oftentimes actors of color are cast to prove that multiculturalism is important. However, the characters often have little cultural specificity and are only different in terms of skin tone. While this type of sameness on the surface may appear to offer a sense of racial parity, it actually encourages the opposite. Colorblindness works to make race immutable and objective, which inevitably disallows difference and instead outputs “whiteness” as the normative standard. Through a series of interviews with casting directors and actors guild diversity representatives as well as an ethnographic account of an actual casting audition, the dissertation argues that for the media industry, colorblindness is both a way of avoiding the messiness of race and of denying actors of color the ability to be culturally specific. This denial occurs because ultimately the desire to work supersedes the desire to reject role universality. As a case study, I examine the hit ABC primetime show Grey’s Anatomy (2005- ) as a way of illustrating how the blindcasting process became a part of public discourse that the television industry both praised and disowned. / text
439

The strength of the evidence for splinting and serial casting as treatment for elbow contractures: an integrative Critical Literature Review

Whitford, Jacki Unknown Date
No description available.
440

Characterization and Evaluation of Aged 20Cr32Ni1Nb Stainless Steels

Dewar, Matthew P Unknown Date
No description available.

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