• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 398
  • 387
  • 87
  • 76
  • 68
  • 59
  • 51
  • 43
  • 27
  • 24
  • 18
  • 7
  • 7
  • 6
  • 5
  • Tagged with
  • 1455
  • 312
  • 240
  • 238
  • 237
  • 191
  • 140
  • 120
  • 114
  • 109
  • 108
  • 104
  • 102
  • 98
  • 97
  • 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.
101

Die uitlewing van talente en sterkpunte as manifestasie van onderwyserveerkragtigheid

Schoeman, Alma January 2017 (has links)
The purpose of this study was to determine whether it has an effect on teachers’ resilience when they live according to their innate talents and strengths. The result of the Clifton StrengthsFinder® (CSF) assessment was used as the basis for this study. I linked Bandura’s social cognitive theory with the CSF and used it as a conceptual framework for the study. Bandura identified four core features of human agency, namely intentionality, forethought, self-reaction and self-reflection. The 34 talent themes identified by the CSF are divided into four domains, namely executional, thinking, influencing and relational. These four domains of talent themes can be partially linked with Bandura’s four core features of human agency. The domains of talent themes cannot be individually and rigidly linked with each of the features identified by Bandura, but there are clearly discernible points of contact between the talent themes and the core features of human agency. In this qualitative study I conducted conversational interviews with eight participants from a phenomenological perspective. Seven participants were female and one male. Five of the participants are educators at private schools; generally not well-resourced, but with small class groups. The other three participants are employed at former Model C schools with significantly more resources, but also much larger class groups. All the educators who participated in this study indicated that the outcome of the CSF assessment described them accurately. Most of the participants live and work according to their strengths and experience that it plays a significant role in their resilience at work. Participants who indicated that they do not live according to their strengths, or use it to a lesser extent, experience limited or no resilience professionally and personally. / Dissertation (Med)--University of Pretoria, 2017. / Humanities Education / MEd / Unrestricted
102

Study of Powder Metal Press and Sinter Process and Its Tool Wear

Thompson, James Kyle 11 August 2007 (has links)
A new methodology was developed to observe and measure tool wear during the die compaction process. The newly developed method is a non-destructive test using silicon rubber to transcript die surface profiles. Tool wear was observed and measured by recording surface roughness and diameter of the cylindrical die replicas on a surface profiler including weight loss in the die. To validate this procedure, an aluminum alloy powder without lubricant was compacted to examine the effect on die wear. The die materials were machined from several wrought and composite materials. A further dimension to the program was the variance of compaction pressures and lubricants.
103

Graphical User Interface for Cooling Line Functions and Surface Rendering

Chen, Xiaorui 05 February 2003 (has links)
No description available.
104

Enhanced Conditions for High Performance Machining of Hardened H13 Die Steel

Elfizy, Aml 08 1900 (has links)
The availability of sophisticated machine tools, together with advanced cutting tool designs and high performance coatings has allowed machining to meet many challenges. A significant remaining challenge is the competitive milling of hardened steels at moderate to high cutting speeds. This is of particular importance for the die and mould making industry. Despite the necessity to achieve higher production rates and improved surface finish, cutting speeds above the range of 300-600 m/min are still not possible. This limitation is due to the combination of high mechanical, thermal and chemical interactions that are taking place on the tool surface during cutting. To address this situation, an extensive amount of research has been focused on developments associated with hard coatings such as nano-multilayered hard PVD coatings that exhibit novel mechanical and thermal properties. The development of methodologies for designing a cutting tool with a strong cutting edge micro-geometry has set guidelines for selecting proper cutting edge preparation for specific cutting applications. The results indicate that, the development of new hard coating designs is the most effective way to improve the service life of coated carbide tools for hard high speed milling applications. The developments of both robust and rigid substrate designs with adaptive cutting edge micro-geometries assist the cutting tool performance by favoring the surface adaptability of the deposited coating. The developments of different strategies for dry air cooling that provide a "soft-cool" environment seem to have a beneficial impact on cutting performance and tool life improvement. Dry air cooling is found to be more effective than chilled-air cooling and minimum-quantity-lubrication (MQL). Therefore, the utilization of a cutting environment tailored to meet the requirements of both the tool and the coating while providing sufficient air flow to remove chips from the cutting zone will complement the adaptability of the whole tool-workpiece-chip system. / Thesis / Master of Applied Science (MASc)
105

Structure evolution and orientation mechanism of long-chain-branched poly (lactic acid) in the process of solid die drawing

Li, J., Li, Z., Ye, L., Zhao, X., Coates, Philip D., Caton-Rose, Philip D. 06 March 2017 (has links)
Yes / Highly oriented long-chain-branched poly (lactic acid) (LCB-PLA) was prepared and the structure evolution was studied in the process of solid die drawing by compared with poly (lactic acid) (PLA). During drawing, samples underwent not only die drawing process but also free drawing process. Drawing speed presented a prominent effect on the free drawing process, while die thickness showed a more obvious influence on the die drawing process. For PLA, free drawing process mainly contributed to its final orientation degree and crystallinity, and thus the mechanical properties of PLA were greatly influenced by drawing speed. However, for LCB-PLA, die drawing process made a greater contribution to the final orientation degree and crystallinity, and its mechanical properties were mainly affected by die thickness. Under the same drawing condition, the tensile strength and modulus of LCB-PLA were always higher than those of PLA, and reached up to 228 MPa and 7.2 GPa, respectively, which basically met the requirement for born fixation materials. Samples which only underwent die drawing showed obvious “sandwich” structure, and the thickness of the oriented skin layer for LCB-PLA was thicker than that for PLA, suggesting that shear-induced orientation can be easily retained due to the enhanced entanglement between long branched chains. After drawing, LCB-PLA samples showed smaller lamellae size (Llateral) but larger long period (Lac) compared with PLA, suggesting that the low chain mobility restricted the motion of chain slipping of LCB-PLA and thus resulted in the fragmentation of neighboring crystal lamella by chain stretched-out.
106

Nanoindentation analysis of oriented polypropylene: Influence of elastic properties in tension and compression

Vgenopoulos, D., Sweeney, John, Grant, Colin A., Thompson, Glen P., Spencer, Paul, Caton-Rose, Philip D., Coates, Philip D. 30 July 2018 (has links)
Yes / Polypropylene has been oriented by solid-phase deformation processing to draw ratios up to ∼16, increasing tensile stiffness along the draw direction by factors up to 12. Nanoindentation of these materials showed that moduli obtained for indenter tip motion along the drawing direction (3) into to 1–2 plane (axial indentation) were up to 60% higher than for indenter tip motion along the 2 direction into the 1–3 plane (transverse indentation). In static tests, tensile and compressive determinations of elastic modulus gave results differing by factors up to ∼5 for strain along the draw direction. A material model incorporating both orthotropic elasticity and tension/compression asymmetry was developed for use with Finite Element simulations. Elastic constants for the oriented polypropylene were obtained by combining static testing and published ultrasonic data, and used as input for nanoindentation simulations that were quantitatively successful. The significance of the tension/compression asymmetry was demonstrated by comparing these predictions with those obtained using tensile data only, which gave predictions of indentation modulus higher by up to 70%.
107

Rapid die manufacturing using direct laser metal deposition

Pereira, M.F.V.T., Williams, M., Bruwer, R. January 2009 (has links)
Published Article / Global issues such as energy and climate changes have impacted on both the automotive and aerospace industries, forcing them to adopt measures to produce products that consume fewer combustibles and emit less carbon dioxide. Making vehicles lighter is one of the logical ways of reducing fuel consumption. The need for light components, able to fulfil technical and quality specifications, led to market growth for tooling that is able to mass produce parts using manufacturing processes such as high pressure die casting. Competitive pressures to reduce the lead time required for tooling-up has also increased dramatically. For this reason research into various methods, techniques and approaches to tool manufacture is being undertaken globally. This paper highlights the work undertaken at the CSIR on the issue of rapid die manufacturing through the application and evaluation of a rapid prototyping technique and coating technologies applied to die components of a high pressure casting die for the production of aluminium components. Criteria for determining suitability were developed against which the technique was evaluated that included time, cost and life-expectancy. Results of accelerated testing procedures to evaluate the die material produced by the rapid prototyping technique and surface coatings and treatments of die materials for their resistance to washout, erosion, heat checking and corrosion in a high pressure die casting environment, are presented. The outcomes of this research will be used for further development and application of specific techniques, design principles and criteria for this approach.
108

Individuum versus Gesellschaft : Die Funktionen des Erzählers in Goethes <em>Werther</em>

Bloom, Karin January 2009 (has links)
No description available.
109

Patrick S??skind's <em>Die Taube</em> und <em>Die Geschichte von Herrn Sommer</em> - innere Zw??nge, Selbstabgrenzung und Objektivierung als Konstituenten von Au??enseiteridentit??ten

Fleischer, Muriel Myriam January 2005 (has links)
The following thesis examines S??skind?s novella <em>Die Taube</em> (1987) and his short-story <em>Die Geschichte von Herrn Sommer</em> (1991) with respect to the literary identities of the outsiders Jonathan Noel and Herr Sommer. The theoretical framework is based on the deep hermeneutic analysis of Alfred Lorenzer?s literary-psychoanalytic theory (1986) which affords one the opportunity of analyzing the personality and concept of life of the literary figures by examining their interactional patterns and relationship to society.
110

Broch, Musil, Canetti, three Austrian novelists of the 1930's : motifs of crime and madness in Die Schlafwandler, Der Mann ohne Eigenschaften, and Die Blendung / by Lois Zweck

Zweck, Lois Beverly January 1973 (has links)
xxi, 437f. ; 26cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1973

Page generated in 0.0451 seconds