1,720,968 research outputs found
Water conservation and demand management: Policy implications at the local level
No full textMagister Artium (Development Studies) - MA(DVS)South Africa is currently experiencing the global phenomenon of water shortage.
Current water requirements for domestic use, industries and agriculture far exceed
local supplies in many parts of the country. It is for this reason that the South African
government has to formulate a variety of policies that govern and regulate the use of
water
Water conservation and demand management: Policy implications at the local level
Full text linkMagister Artium (Development Studies) - MA(DVS)South Africa is currently experiencing the global phenomenon of water shortage.
Current water requirements for domestic use, industries and agriculture far exceed
local supplies in many parts of the country. It is for this reason that the South African
government has to formulate a variety of policies that govern and regulate the use of
water
Epitaxy on substrates with hexagonal lattice symmetry
Full text linkThesis (DSc)--University of Pretoria, 1987.A general description of epitaxy between thin films and substrates of any crystal symmetry was developed from a model in which both overgrowth and substrate are initially kept rigid (Chapter 3). The overgrowth-substrate interaction is described by Fourier series, usually truncated, defined on the surface reciprocal lattice vectors of the crystal faces in the interface (Chapter 2). Energy considerations lead directly to a criterion for the existence of epitaxial configurations which occur when a pair of surface reciprocal lattice vectors of the substrate and overgrowth coincide. This criterion is analogous to the von Laue criterion and Bragg equation in diffraction theory, and has a geometrical realization related to the Ewald construction. Generalized, the formulation allows the calculation of misfit strain, (Chapter 4) and the description of interfacial structures in terms of misfit dislocation arrays or verniers (Chapter 5) - the spacing, line sense and Burgers vectors are obtained from the reciprocal lattice for an interface between crystals of the most general and diverse symmetry. The most general structures can be treated with convenient unit cells by using structure factors. Parallel to the predictions from reciprocal space, the homogeneous misfit strain (Chapter 4), the interfacial atom positions after relaxation (Chapter 5) and misfit and strain energies (both chapters) were obtained by direct numerical minimization of the total interfacial energy of a large (1105 atoms) but finite system.PhysicsDScUnrestricte
The geography of education: new frontiers [Die geografie van onderwys: nuwe fronte]
No full textThe prominence of education as a prerequisite for social and economic development necessitates continuous research on all elements of the subject. Drawing on an exhaustive overview of literature from all disciplines addressing spatial aspects of education-related issues, the scope for geographical research in this field is discussed. Paradigmatic vantage points from the divergent positivist and structuralist schools are compared and the spatial approach is justified. In conclusion a scheme is devised to accommodate research on the geography of education from a reformist epistemology. A scale-specific approach is recommended which allows traditional geographers to study spatial inequalities in education at the meso and macro scale. Structuralist theory accounting for the effects/outcomes of the educational system is considered more appropriate for studies at the micro scale. -from English summar
( Land use change in the rural-urban fringe of Cape Town). [Grondgebruikverandering in die landelikstedelike oorgangsone van Kaapstad.]
No full textThe spatial expansion characteristic of modern cities is mainly concentrated along the edge of built-up urban areas. This intermingling of often incompatible urban and rural land uses leads to the development of a rural-urban fringe which often constitutes a problem area within the wider city structure. This paper evaluates the effect of urban expansion on the fringe zone from a reconstruction of successive land use patterns(1960 and 1977) for Cape Town. The nature of the process of areal urban expansion is detailed. Final urbanization is shown to be preceded by a preparatory phase in which typical fringe land use types are located along an ill-defined transition zone adjacent to the built-up urban boundary.-English summar
Stellenbosch Rugby Touring Team, 1923
No full textDonated by Mrs. E.C. Keyter.Left to right: W.H. Myburgh, W. Retief, J. de W. Keyter, J.S. Marais, R. Keet, G. Pienaar, P. Morkel, B. Malherbe, C. Gronum, J. du Toit, J. Loots, J.A. Brink, M.N. Theron, H.A. Kotze, S.F. du Toit, W. Louw, W. Smith, P.H. de Villiers, J. van Wyk, J. van Reenen, P.R. van der Merwe, J.H. van der Walt, J. Lochner. Inset: J.J. de Villiers, A.F. Markotter, T. du Toit, O. Langenegger.Photomerge created, image cropped.Black and white photograph depicting the Stellenbosch rugby touring team
The calculation of adsorption parameters using embedded atom methods
Full text linkThesis (Dphil)--University of Pretoria, 1990.A comparative investigation to assess embedded atom methods for the calculation of the suitability of various adsorption properties of systems consisting of homo- and heteronuclear bee metals have been undertaken. Homonuclear systems consisting of a tungsten adatom and an infinite tungsten monolayer adsorbed on a tungsten {110} substrate, were considered. For heteronuclear systems, the case of a tantalum adatom adsorbed on a tungsten {110} surface was analysed. The embedded atom methods introduced by Gollisch, by Johnson and Oh, and by Finnis and Sinclair were applied to the homonuclear system. The latter two models were also applied to the heteronuclear system. For both systems the potential of Finnis and Sinclair have been extended for application to {110} tungsten surfaces, introducing an additional parameter fitted to the empirical value of the adatom-surface migration energy. Appropriate definitions for the desorption energy and the adatom-surface migration energy in terms of N-body potentials, were formulated. In addition, the vibration frequencies and coefficients for a truncated Fourier representation of the adatom-surface interaction potential were also calculated numerically. The potential models were assessed on their ability to reproduce the experimental values of the adatom-surface migration energy and the desorption energy, as well as the presence of a double well in the potential surface at an adsorption site on tungsten {110} substrates. The surface modified model of Finnis and Sinclair appeared to be the most suitable potential for application to the homonuclear system, whereas, for the heteronuclear system, no specific model could be identified as being the most appropriate. For the homonuclear system, all N-body potentials yielded more realistic values of the adatom-surface migration energy, the desorption energy and the adatom-substrate equilibrium height than the conventional Morse and Lennard-Jones pair potentials. The magnitude of optimized Fourier coefficients for truncated Fourier series representations of the adatom-substrate interaction potential were shown to decay rapidly with harmonic order. This justifies the implementation of Fourier series truncated at low harmonic order for the theoretical description of isolated adsorbates on crystal surfaces. The relative values of the normalized Fourier coefficients appeared to be largely determined by the symmetry of the substrate. The success of embedded atom methods in describing surface phenomena was attributed mainly to their ability to incorporate environmental effects on bonding; while requiring only slightly more computational effort than pair potentials.PhysicsDPhilUnrestricte
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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