Researching the South African tourism and development nexus   总被引：1，自引：0，他引：1  

Gustav Visser  Christian M. Rogerson 《GeoJournal》2004,60(3):201-215

Under apartheid, tourism was essentially anti-developmental in focus and tourism research largely centred on the recreation of white South Africans. Since the 1994 democratic transition tourism has become recognised as an increasingly important sector for South Africa's economy and for achieving the government's goals for reconstruction and development. In this paper a review and critical analysis is presented of the changing directions and foci of tourism scholarship in South Africa. It is shown that South African scholars are beginning to respond to the challenges posed by tourism as a developmental focus. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Pore-water pressure development in a frozen saline clay under isotropic loading and undrained shearing     

Lyu  Chuangxin  Nishimura  Satoshi  Amiri  Seyed Ali Ghoreishian  Zhu  Feng  Eiksund  Gudmund Reidar  Grimstad  Gustav 《Acta Geotechnica》2021,16(12):3831-3847

Acta Geotechnica - A systematical testing program on frozen Onsøy clay under isotropic loading and undrained shearing at different temperatures...  相似文献   

Relating remotely sensed forest damage data to wind data: storms Lothar (1999) and Vivian (1990) in Switzerland     

Tilo Usbeck  Peter Waldner  Matthias Dobbertin  Christian Ginzler  Christian Hoffmann  Flurin Sutter  Charlotte Steinmeier  Richard Volz  Gustav Schneiter  Martine Rebetez 《Theoretical and Applied Climatology》2012,108(3-4):451-462

This study compares the surface wind speed and forest damage data of two exceptionally severe winter storms, Vivian 1990 and Lothar 1999. The study area comprises the region that suffered damage in Switzerland. The wind speed data were derived from simulations of MeteoSwiss (Federal Office of Meteorology and Climatology), measurements during the storm periods and expert analyses of the data. The remotely sensed forest damage data were provided by the Federal Office for the Environment and the forest cover data by Swiss Federal Statistical Office. We compared data on the peak gust and maximum average wind speed, with data on the spatially related forest area and forest damage area, and found some clear differences in the correlations between the different wind data and forest damage. Our results point generally to the damage-causing role of near-surface gusts at maximum wind speeds during the storm. These tended to be spatially distributed on a fine scale. In only a few cases were the results statistically significant. However, these results could probably be improved with better wind data. For example, gust measurements spatially closer to forests or simulations of gusts at maximum wind speed could be produced with a spatially higher resolution.  相似文献   

Übersicht über die vulkanische Tätigkeit 1941–1947     

Gustav Hantke 《Bulletin of Volcanology》1951,11(1):161-208

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Übersicht über die vulkanische Tätigkeit 1948–1950     

Gustav Hantke 《Bulletin of Volcanology》1953,14(1):151-184

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Wärmehaushalt und Advektion     

Gustav Hofmann 《Meteorology and Atmospheric Physics》1960,11(4):474-502

Zusammenfassung Der Feststellung, daß in der Energiebilanz einer horizontalen Oberfläche keine advektiven Glieder auftreten können, scheint auf den ersten Blick die Angabe von Advektionsgliedern in einigen Arbeiten zu widersprechen. Es zeigt sich aber, daß es sich dabei entweder um die Energiebilanz eines Volumens handelt, wobei die Glieder der Vergleichbarkeit wegen auf die Bodenoberfläche bezogen sind, oder daß Meß- bzw. Überlegungsfehler vorliegen.Advektive Wärmeströme können nur bei einem Volumen eine Rolle spielen. Die Betrachtung der Energiebilanz eines festen Volumens ergibt dann, daß auch bei stationären Verhältnissen der Wärmestrom von der Luft zum Boden im allgemeinen nicht gleich dem vertikalen Austauschwärmestrom oberhalb der Bodenoberfläche ist. Vielmehr treten vier weitere Wärmeströme hinzu, die als Durchflußwärmestrom, vertikaler Mitführungswärmestrom, advektiver Mitführungswärmestrom und advektiver Austauschwärmestrom bezeichnet werden. Ihr Anteil am Wärmestrom von der Luft zum Boden hängt nicht nur von den meteorologischen Verhältnissen, sondern auch von der Höhenlage der Zählfläche ab, für die der Austauschwärmestrom bestimmt wird. Ihre Abschätzung an Hand einfacher, plausibler Annahmen zeigt, daß sie im allgemeinen nicht vernachlässigt werden dürfen. Eine hinreichende Bedingung für ihr Verschwinden ist die Annahme, daß im zeitlichen Mittel alle Parameter in gleicher Höhe den gleichen Wert haben. Auch für instationäre Verhältnisse und den Wärmetransport in einem inhomogenen Medium läßt sich die Energiebilanz aufstellen, was aber bei Änderungen der im Volumen enthaltenen Masse an Beimengung nicht mehr willkürfrei möglich ist.

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Summary The statement that no advective terms occur in the energy balance of a horizontal surface seems at first sight to be in contradiction to the quotation of advective terms in some publications. It proves, however, that in that case it is a question of energy balance of a volume, where for comparability the terms are related to the ground surface, or that it is due to errors of measurement or consideration. Advective heat fluxes are merely of importance with three-dimensional problems. The study of the energy balance of a solid volume shows that the heat flux from the air to the ground is generally not equal to the vertical exchange heat flux above the ground surface, even with stationary conditions. Four further heat fluxes supervene which may be designated as passing heat flux, vertical convection heat flux, advective convection heat flux and advective exchange heat flux. Their share of heat flux from the air to the ground depends not only on the meteorological conditions but also on the altitude of the reference surface for which the exchange heat flux is determined. Its estimation by simple, plausible assumptions shows that in general they should not be neglected. A sufficient condition for their disappearance is the assumption that all parameters at the same level have the same temporal mean value. The energy balance can be set up also for unstationary conditions and for the heat transport in an inhomogeneous medium. In the case where the mass of admixtures contained in the volume undergoes changes the energy balance cannot be established without arbitrary assumptions.

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Résumé Le fait que dans le bilan énergétique d'une surface horizontale il ne peut y avoir de terme advectif semble à première vue contredire certains travaux qui en ont fait état. Mais il s'avère qu'il s'agit soit du bilan énergétique d'une volume, soit d'une erreur de mesure ou de raisonnement.Des courants advectifs de chaleur ne peuvent jouer de rôle que dans le cas d'un volume. Considérant le bilan énergétique d'un volume fixe, on voit que même dans l'état stationnaire le flux de chaleur dirigé de l'air vers le sol n'est pas égal en général au courant vertical d'échange turbulent au-dessus du sol; bien plus, il existe en réalité quatre autres flux (à savoir le flux de chaleur traversant, le flux vertical de chaleur convective, le flux de chaleur advective et le flux d'échange de chaleur advective) dont l'apport au flux de chaleur air/sol ne dépend pas seulement des conditions météorologiques, mais aussi de l'altitude de la surface choisie pour le calcul. L'estimation de ces flux, faite sur la base d'hypothèses simples et plausibles, montre qu'on ne peut pas en général les négliger. Ils ne peuvent disparaître que si en moyenne, dans un temps donné, tous les paramètres sont égaux, à la même altitude. Dans le cas d'états non stationnaires et de milieu non homogène, on peut dresser le bilan énergétique, ce qui n'est plus possible sans arbitraire lorsque la masse d'éléments adjonctifs du volume se modifie.

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The developmental impacts of backpacker tourism in South Africa     

Gustav Visser 《GeoJournal》2004,60(3):283-299

South Africa has recorded considerable growth in tourism activity over the past decade. In the light of the vast range of economic sectors that gain from tourism development, the national government has instituted a range of incentives and initiatives to stimulate tourism development, with the expansion of tourism infrastructure aimed at high-end tourists forming a key component of this strategy. Little investment has, however, been made in tourism infrastructure targeting those markets that prefer to avoid high-end tourism facilities. In this respect backpacker tourists and their preferred accommodation type, backpacker hostels, are a case in point. Despite backpacker tourism being largely ignored in national tourism development initiatives, backpacker tourism is increasingly popular in South Africa. This paper focuses on the recent proliferation of backpacker tourism in this country and seeks to convey the results of the first nation-wide exploration in this regard. The paper has two main objectives. Firstly, it seeks to present broad-ranging empirical data concerning this tourist cohort and their preferred accommodation type- backpacker hostels — in the South African context. Secondly, it aims to demonstrate why backpacker tourists and hostels hold much potential for local development initiatives in South Africa. In the light of the findings of this study, the paper concludes that the expansion of backpacker tourism to this country might form an appropriate means by which to achieve a range of local development objectives.  相似文献   

A new laboratory set-up for measurements of electrical, hydraulic, and osmotic fluxes in clays   总被引：4，自引：0，他引：4  

Katja Heister  Pieter J. Kleingeld  Thomas J.S. Keijzer  J.P. Gustav Loch 《Engineering Geology》2005,77(3-4):295-303

If clays are subjected to flows of fluid, electrical charge, chemicals, or heat, in most cases, flows of different types occur simultaneously, even if only one driving force is acting. These are so-called coupled flows. Examples of coupling phenomena are streaming potential and electroosmosis, induced by the flows of fluid and electrical charge, respectively.

Since the 1960s, laboratory devices have been constructed to measure streaming potentials and/or electroosmosis in clays or clayey soils. Due to their mechanical and hydraulic properties, clays are not easy to work with. Consequently, laboratory devices have to deal with various complications. A new design for an experimental set-up is proposed. Contrary to earlier devices, the clay sample is mounted in a flexible wall permeameter, which avoids sidewall leakage caused by the possible swell or shrink of the clay. Gold-coated gauze electrodes completely cover the surfaces of the sample, which are in contact with the solution reservoirs that ensure one-dimensional flow. In addition, the thickness of the sample is monitored during the experiment. The chemical composition of the reservoir fluids is controlled during the experiment. The device is flexible with respect to changing the solutions of both reservoirs independently, applying different hydraulic gradients, and measuring or applying electrical potentials. Finally, it is possible to mount undisturbed clay samples in the set-up, keeping them in situ during the whole experiment.

With this set-up, an extensive program of measurements of coupling phenomena like streaming potentials, electroosmosis, and membrane potentials in a sodium montmorillonite is started. Preliminary results of streaming potential measurements are presented and demonstrate that the build-up of a streaming potential due to a hydraulic gradient is a reproducible process that influences the water flow through the clay, and that the extent of the streaming potential depends on the salt concentration of the permeating solution.  相似文献   

Fault-related mineralization in the Western Fold Belt,Mt Isa: Targeting copper using an integrated approach     

Gustav S. Nortje  Nicholas H.S. Oliver  Damien L. Keys  John G. McLellan  Steven Oxenburgh 《Journal of Geochemical Exploration》2009

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On the recognition of areas with problematic sulphidic sediments using multi-disciplinary data     

G. Sohlenius  M. Bastani  L. Persson  K. Lax 《Environmental Geology》2009,56(5):973-984

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