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  • Cambridge University Press  (64)
  • 2000-2004  (21)
  • 1985-1989  (29)
  • 1970-1974  (14)
  • 1940-1944
  • 1
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    Alfred Russel Wallace; some notes on the Welsh connection (1989)
    Cambridge : Cambridge University Press
    The @British journal for the history of science 22 (1989), S. 401-418 
    Details
    ISSN: 0007-0874
    Quelle: Cambridge Journals Digital Archives
    Thema: Geschichte , Allgemeine Naturwissenschaft
    Notizen: Wallace became a full-time naturalist in 1848, the year when he and Bates set out on their journey to South America. Wallace was twenty-five at the time and over half of his life had been spent in various parts of Wales, the land of his birth. Commentators have tended to gloss over or ignore any formative influences from this early period of his life or even to dismiss them as non-existent. This is surprising as it was during the eight or so years in Wales leading up to 1848 that Wallace's interest in natural history emerged. ‘The importance of this early period in Wallace's life can scarcely be over-emphasized’ wrote Durant in his account of the development of the Wallace personality, but he omitted any specific reference to the significance of the early period in Wales. Those seeking a simple unitary cause for Wallace's conversion to natural history usually locate this in his visit to Leicester in 1844 and his meeting there with H. W. Bates. ‘The odyssey began ... in 1844, in Leicester’ wrote Brooks, adding that ‘the more remote parts of ... southern Wales had offered little reading material...’ This, and similar claims, are presumably founded primarily on Wallace's belief—expressed sixty years later—that it was at Leicester that he first familiarized himself with Malthus' Essay on the Principles of Population and Humboldt's Personal Narrative of Travels in South America. There is, however, evidence that Wallace was probably familiar with at least one of these books some time before his visit to Leicester and that it was during his period in southern Wales that his interest in natural history emerged and developed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1017/S0007087400026352
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
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    Model Builders and Instrument Makers (1988)
    Cambridge : Cambridge University Press
    Science in context 2 (1988), S. 59-75 
    Details
    ISSN: 0269-8897
    Quelle: Cambridge Journals Digital Archives
    Thema: Geschichte , Allgemeine Naturwissenschaft
    Notizen: The ArgumentMany inventors, engineers, and scientists think in verbal images. Elmer Sperry (1860–1930), a noted American inventor, was able to “operate” in his mind's eye the machines he was developing. For inventors, engineers, and experimental scientists, visualization is often followed by construction of a physical model of the invention, which can be an experimental apparatus. The model, or apparatus, is then tested in increasingly complex environments and changes are made in the physical artifact until it is ready to be used. Examples of this process of development are Sperry's development of a ship stabilizer for the U.S. Navy and a revolving mirror to be used by Albert Michelson in the determination of the speed of light. Thomas Edison called experimentation his development of an invention through the building and testing of a series of models. So, both scientists and inventors experiment. They are not discovering the “secrets of nature”: they are observing how artifacts – their physical creations – behave. These physical models of thought reflect the characteristics of the tools with which they were made. They are socially constructed, as well.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1017/S0269889700000491
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  • 3
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    Shear layers driven by turbulent plumes (2001)
    Cambridge University Press
    Details
    Publikationsdatum: 2001-05-10
    Beschreibung: A turbulent plume from a continuous source of buoyancy in a long tank is shown to generate a series of quasi-steady counterflowhng horizontal shear layers throughout the tank. Both the horizontal flow velocity and the depth of the shear layers are observed to decrease with distance above/below the plume outflow. The shear layers are supported by the stable density stratification produced by the plume and are superimposed on the vertical advection and entrainment inflow that make up the so-called 'filling box' circulation. Thus, at some depths, the surrounding water flows away from the plume instead of being entrained, although we see no evidence of 'detrainment' of dense plume water. Given the stratification produced by the plume at large times, the timescale for the velocity structure to adjust to changes in forcing is proportional to the time for long internal gravity waves to travel the length of the tank. The shear layers are interpreted in terms of internal normal modes that are excited by, and which in turn determine, the horizontal plume outflow. The sixth and seventh baroclinic modes typically dominate because at the level of the plume outflow their phase speed is approximately equal and opposite to the vertical advection in the 'filling box'. Also, the approximate balance between phase speed and advection is found to hold throughout the tank, resulting in the observed quasi-steady flow structure. Viscosity causes the horizontal velocity in the shear layers to decrease with distance above/below the plume outflow, and is thought to be responsible for a low-frequency oscillation in the flow structure that is observed during experiments.
    Print ISSN: 0022-1120
    Digitale ISSN: 1469-7645
    Thema: Maschinenbau , Physik
    Publiziert von Cambridge University Press
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  • 4
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    Solution of the wedge entry problem by numerical conformal mapping (1972)
    Cambridge University Press
    Details
    Publikationsdatum: 1972-11-14
    Beschreibung: An accurate quasi-analytic method of solution is presented for the classical hydrodynamics problem of the constant-velocity entry of a prismatic wedge into a weightless incompressible inviscid fluid. The method uses the Wagner function W, which reduces the problem to the determination of a mapping function λ = ℒ(W) for the hodograph. ℒ(W) is constructed by using the hodograph for an unsymmetric diamond together with a modifying or ‘preparatory’ trans-formation. A computer method of conformal mapping is developed and is used to obtain this latter transformation. Results are presented for the case of a 90° wedge and show that the solution is both more accurate than previous solutions, having an error of less than 1 %, and more complete, as it portrays the entire flow field and furnishes information about the functional dependence among the variables. © 1972, Cambridge University Press. All rights reserved.
    Print ISSN: 0022-1120
    Digitale ISSN: 1469-7645
    Thema: Maschinenbau , Physik
    Publiziert von Cambridge University Press
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  • 5
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    The nonlinear properties of a large-scale dynamo driven by helical forcing (2002)
    Cambridge University Press
    Details
    Publikationsdatum: 2002-04-09
    Beschreibung: By considering an idealized model of helically forced flow in an extended domain that allows scale separation, we have investigated the interaction between dynamo action on different spatial scales. The evolution of the magnetic field is studied numerically, from an initial state of weak magnetization, through the kinematic and into the dynamic regime. We show how the choice of initial conditions is a crucial factor in determining the structure of the magnetic field at subsequent times. For a simulation with initial conditions chosen to favour the growth of the small-scale field, the evolution of the large-scale magnetic field can be described in terms of the α-effect of mean field magnetohydrodynamics. We have investigated this feature further by a series of related numerical simulations in smaller domains. Of particular significance is that the results are consistent with the existence of a nonlinearly driven α-effect that becomes saturated at very small amplitudes of the mean magnetic field.
    Print ISSN: 0022-1120
    Digitale ISSN: 1469-7645
    Thema: Maschinenbau , Physik
    Publiziert von Cambridge University Press
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  • 6
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    On the scattering of baroclinic Rossby waves by a ridge in a continuously stratified ocean (2002)
    Cambridge University Press
    Details
    Publikationsdatum: 2002-08-25
    Beschreibung: In global ocean dynamics Rossby waves play a vital rôle in the long-term distribution of vorticity; knowledge of the interaction between these waves and topography is crucial to a full understanding of this process, and hence to the transportation of energy, mixing and ocean circulation. The interaction of baroclinic Rossby waves with abrupt topography is the focus of this study. In this paper we model the ocean as a continuously stratified fluid for which the linear theory predicts a qualitatively different structure for the wave modes than that predicted by barotropic or simple layered models, even if most of the density variation is confined to the thermocline. We consider the scattering of a westward-propagating baroclinic Rossby wave by a narrow ridge on the ocean floor, modelled by a line barrier of infinite extent, orientated at an arbitrary angle to the incident wave. Transmission and reflection coefficients for the propagating modes are found using both an algebraic method and, in the case where this breaks down, matched asymptotic expansions. The results are compared with recent analyses of satellite altimetry data.
    Print ISSN: 0022-1120
    Digitale ISSN: 1469-7645
    Thema: Maschinenbau , Physik
    Publiziert von Cambridge University Press
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  • 7
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    Convection driven by differential heating at a horizontal boundary (2004)
    Cambridge University Press
    Details
    Publikationsdatum: 2004-10-10
    Beschreibung: We report laboratory and numerical experiments with the convective circulation that develops in a long channel driven by heating and cooling through opposite halves of the horizontal base. The problem is similar to that posed by Stommel (Proc. Natl Acad. Sci. vol. 48, 1962, p. 766) and Rossby (Deep-Sea Res. vol. 12, 1965, p. 9; Tellus vol. 50, 1998, p. 242), where flow forced by a linear temperature variation along the ocean surface or the base of a tank presented a demonstration of the smallness of sinking regions in the meridional overturning circulation of the oceans. In contrast to the previous experiments, we use small aspect ratio, larger Rayleigh numbers, piecewise uniform boundary conditions and an imposed input heat flux. The flow is characterized by a vigorous overturning circulation cell filling the box length and depth. A stable thermocline forms above the cooled base and is advected over the heated part of the base, where it is eroded from below by small-scale three-dimensional convection, forming a 'convective mixed layer'. At the endwall, the convective mixing is overshadowed by a narrow but turbulent plume rising through the full depth of the box. The return flow along the top of the box is turbulent with large slowly migrating eddies, and occupies approximately a third of the total depth. Theoretical scaling laws give temperature differences, thermocline thickness and velocities that are in good agreement with the experimental data and two-dimensional numerical solutions. The measured and computed density structure is largely similar to the thermocline and abyssal stratification in the oceans. © 2004 Cambridge University Press.
    Print ISSN: 0022-1120
    Digitale ISSN: 1469-7645
    Thema: Maschinenbau , Physik
    Publiziert von Cambridge University Press
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  • 8
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    Science and technology in historic preservation. Ray A. Williamson and Paul R. Nickens (Editors). 2000. Dordrecht: Kluwer Academic Publishers, xxii + 357 p, hard cover. ISBN 0–306-46212–5. £58.75; US$85.00; NLG200. (2002)
    Cambridge University Press
    Details
    Publikationsdatum: 2002-01-01
    Print ISSN: 0032-2474
    Digitale ISSN: 1475-3057
    Thema: Ethnologie , Geographie
    Publiziert von Cambridge University Press
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
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    Ten myths about the preservation of historic sites in Antarctica and some implications for Mawson's huts at Cape Denison (2000)
    Cambridge University Press
    Details
    Publikationsdatum: 2000-04-01
    Beschreibung: A review of popular writing on the subject of preservation of historic sites in Antarctica, including buildings, graves, and artefacts, has revealed many misconceptions about the existence and cause of deterioration problems. These myths include the belief that the artefacts inside the Ross Dependency huts are in a near perfect state of preservation and that there is no corrosion in Antarctica because of the dry cold. Further examination, however, shows these views to be incorrect. These and other misconceptions are classified into three groups: (1) misunderstanding or denial of deterioration processes in Antarctic conditions; (2) simplistic assumptions about how historic buildings should be conserved in Antarctica; and (3) inappropriate comparisons between dissimilar sites.There has been considerable debate in Australia and New Zealand about how historic Antarctic buildings should be preserved. Proposed preservation methods have covered a wide range from dismantling and repatriation to a museum, re-cladding with new timber, insertion of vapour barriers inside walls to exclude ice ingress, covering buildings with a dome, and, at the other end of the spectrum of views, minimal intervention. The preservation of artefacts has also been an issue, particularly concerning whether artefacts can be effectively preserved in Antarctica or whether it is necessary to treat and store them at museums outside Antarctica. It is important to encourage consideration of all appropriate means of preservation, but it is particularly important that the causes of deterioration are understood (that is, correct diagnosis) before prescribing treatment.
    Print ISSN: 0032-2474
    Digitale ISSN: 1475-3057
    Thema: Ethnologie , Geographie
    Publiziert von Cambridge University Press
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  • 10
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    Cambridge University Press
    Details
    Publikationsdatum: 2004-09-01
    Print ISSN: 0033-5894
    Digitale ISSN: 1096-0287
    Thema: Geographie , Geologie und Paläontologie
    Publiziert von Cambridge University Press
    Standort Signatur Erwartet Verfügbarkeit
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