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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.
271

An investigation of the deep drawing process with the application of ultrasonic oscillations

Smith, Alan W. January 1977 (has links)
No description available.
272

An analysis of the effect of process parameters on the formability of sheet metal

Lee, Peter K. January 1972 (has links)
This investigation is in two parts, theory and experimental verification. (1) Theoretical Study In this study it is, for obvious reasons, necessary to analyse the concept of formability first. For the purpose of the present investigation it is sufficient to define the four aspects of formability as follows: (a) the formability of the material at a critical section, (b) the formability of the material in general, (c) process efficiency, (d) proportional increase in surface area. A method of quantitative assessment is proposed for each of the four aspects of formability. The theoretical study also includes the distinction between coaxial and non-coaxial strains which occur, respectively, in axisymmetrical and unsymmetrical forming processes and the inadequacy of the circular grid system for the assessment of formability is explained in the light of this distinction. (2) Experimental Study As one of the bases of the experimental work, the determination of the end point of a forming process, which sets the limit to the formability of the work material, is discussed. The effects of three process parameters on draw-in are shown graphically. Then the delay of fracture in sheet metal forming resulting from draw-in is analysed in kinematical terms, namely, through the radial displacements, the radial and the circumferential strains, and the projected thickness of the workpiece. Through the equilibrium equation of the membrane stresses, the effect on the shape of the unsupported region of the workpiece, and hence the position of the critical section is explained. Then, the effect of draw-in on the four aspects of formability is discussed throughout this investigation. The triangular coordinate system is used to present and analyse the triaxial strains involved. This coordinate system has the advantage of showing all the three principal strains in a material simultaneously, as well as representing clearly the many types of strains involved in sheet metal work.
273

System interfacing for on-line computer control

Rakic, M. J. January 1976 (has links)
No description available.
274

Precision crystal oscillator design

Wilson, J. S. January 1983 (has links)
No description available.
275

In-process weld quality monitoring techniques for resistance-spot welds

Bhattacharya, Sabyasachi January 1972 (has links)
No description available.
276

Managing the impact on biodiversity of supply chain companies

Whatling, Derek R. January 2010 (has links)
Industrial development has had a major role in creating the situation where bio-diverse materials and services essential for sustaining business are under threat. A key contributory factor to biodiversity decline comes from the cumulative impacts of extended supply chain business operations. In order to contribute to stopping this decline, the industrial world needs to form a better understanding of the way it utilizes the business and biodiversity agenda in its wider operations. This thesis investigates the perceptions and attitudes to biodiversity from government, society and a wide cross-section of industry. The research includes the extent of corporate attention to and use of environmental business tools and guidelines in reporting on biodiversity issues. A case study of three companies from different industrial sectors is undertaken to observe procurement and related environmental management of their supply chains. The use of accredited and non-accredited environmental management systems (EMS) are analysed as frameworks for introducing biodiversity aspects into supply chain management. The outcome is a methodology, which can be used either as a bespoke in-house biodiversity management system or within an accredited ISO 14001 EMS, for incorporating the assessment and management of the potential risks and opportunities involving environmental impacts on biodiversity of supply chain companies.
277

Object oriented petri net modelling and analysis of large production systems

Konstas, Nikolaos-Kyriakos January 1999 (has links)
No description available.
278

Computer aided design of a press tool run-off

Harrison, Keith January 1990 (has links)
This thesis is concerned with the design of press tool run-ofts. Run-off is the area on the punch surrounding the panel and its shape is of great importance to the control of metal flow during the draw. The design, although influenced by engineering considerations, is principally a geometric problem, which traditionally has been time-consuming. The overall objective is to reduce the run-oft definition time and hence improve the lead time. Current Austin Rover design procedures are described in Chapter 2 and form the basis of the C.A.D. program outlined in Chapter 3. This specification distils the need for a number of geometric algorithms. In general, obtaining the required continuity between the panel and run-off surface will require some degree of boundary curve approximation. Chapter 4 details four alternative approximation techniques which are compared in Chapter 5; and constitute the main results of the thesis. The salient issues of run-off surface interpolation are considered in Chapter 6.
279

The relevance of the hierarchy model of market entry modes to South African manufacturing firms entering Mozambique.

Davis, Tracey Beverley January 2006 (has links)
The decision to enter a foreign market has long-term implications for the investing firm, as has its choice of entry mode. The hierarchical model of market entry modes proposes that entry modes can be categorised as equity-based or non-equity based, and further categorised by type as joint ventures and wholly owned subsidiaries, exports and contractual agreements. The hierarchical model of market entry modes proposes that there are factors that influence the entry mode at the level of equity versus non-equity but not within the type of equity or non-equity.
280

Stanovení optimální lisovací síly a rychlosti lisování pro výrobu tablet s obsahem acikloviru / Determination of optimal compression force and speed of compression for the production aciclovir tablets

Vlachová, Hana January 2014 (has links)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Student: Vlachová Hana Consultant: Doc. RNDr. Milan Řehula, CSc. Determination of optimal compression forces and speed of compression for the production of aciclovir tablets. This thesis deals with the characterisation of impact compression process on hardness of the tablets. The theoretical part of the thesis describes the effective substance - aciclovir. It also describes compression equations which explain process of compression and factors influencing terminal weight and hardness of tablets. The aim of the experimental part of the work is to measure physical properties of the tablets and find compression forces and speed of compression which are suitable for compression tablets. Tablets were pressed using Kilian Synthesis 700 machine at six compression forces in the range from 4 kN to 14 kN. The height, weight and hardness of each tablet were measured immediately after dressing and note to help for later calculation. The result of the study was to determine the impact of compression forces and compression speed on tablet hardness and weight. Tablet weight decreses with increasing comppession forces. Hardness increases with increasing compression forces. The range of radial hardness...

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