ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Model Builders and Instrument Makers (1988)
    Cambridge : Cambridge University Press
    Science in context 2 (1988), S. 59-75 
    Details
    ISSN: 0269-8897
    Source: Cambridge Journals Digital Archives
    Topics: History , Natural Sciences in General
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1017/S0269889700000491
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    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
    Source: Cambridge Journals Digital Archives
    Topics: History , Natural Sciences in General
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1017/S0007087400026352
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    facet.materialart.
    Unknown
    Cambrian rocks and faunas of the Wachi La, Black Mountains, Bhutan (2011)
    Cambridge University Press
    Details
    Publication Date: 2011-05-01
    Description: The Pele La Group in the Wachi La section in the Black Mountains of central Bhutan represents the easternmost exposure of Cambrian strata known in the Himalaya. The group contains a succession of siliciclastic rocks with minor amounts of carbonate, the uppermost unit of which, the Quartzite Formation, bears age-diagnostic trilobite body fossils that are approximately 493 Ma old. Trilobite species include Kaolishania granulosa, Taipaikia glabra and the new species Lingyuanaspis sangae. A billingsellid brachiopod, Billingsella cf. tonkiniana, is co-occurrent. This fauna is precisely correlated with that of a specific stratigraphic horizon within the upper part of the Kaolishania Zone, Stage 9 of the Cambrian System, Furongian Epoch of the North China block, and thus represents the youngest Cambrian sedimentary rocks yet known from the Himalaya. The faunal similarity suggests proximity between North China and the Himalayan margin at this time. This unit was deposited in a predominantly storm-influenced shelf and shoreface environment. U-Pb geochronological data from detrital zircon grains from the fossil-bearing beds of the Quartzite Formation and strata of the underlying Deshichiling Formation show grain age spectra consistent with those from Cambrian rocks of the Lesser and Tethyan Himalaya in Tibet, India and Pakistan. These data support continuity of the northern Gondwanan margin across the Himalaya. Prominent peaks of approximately 500 Ma zircons in both the Quartzite and Deshichiling formations are consistent with the Furongian (late Cambrian) age assignment for these strata. The presence of these relatively young zircon populations implies rapid post-cooling erosion of igneous bodies and subsequent deposition which may reflect the influence of a widespread Cambro-Ordovician orogenic event evident in the western Himalaya.
    Print ISSN: 0016-7568
    Electronic ISSN: 1469-5081
    Topics: Geosciences
    Published by Cambridge University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    An inexact GaussNewton method for inversion of basal sliding and rheology parameters in a nonlinear Stokes ice sheet model (2012)
    Cambridge University Press
    Details
    Publication Date: 2012-10-06
    Print ISSN: 0022-1430
    Electronic ISSN: 1727-5652
    Topics: Geography , Geosciences
    Published by Cambridge University Press on behalf of The International Glaciological Society (IGS).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Are ice-stream tributaries the surface expression of thermal convection rolls in the Antarctic ice sheet? (2012)
    Cambridge University Press
    Details
    Publication Date: 2012-08-26
    Print ISSN: 0022-1430
    Electronic ISSN: 1727-5652
    Topics: Geography , Geosciences
    Published by Cambridge University Press on behalf of The International Glaciological Society (IGS).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Estimates of the refreezing rate in an ice-shelf borehole (2013)
    Cambridge University Press
    Details
    Publication Date: 2013-11-13
    Print ISSN: 0022-1430
    Electronic ISSN: 1727-5652
    Topics: Geography , Geosciences
    Published by Cambridge University Press on behalf of The International Glaciological Society (IGS).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    The structure and petrology of the Cnoc nan Cuilean Intrusion, Loch Loyal Syenite Complex, NW Scotland (2013)
    Cambridge University Press
    Details
    Publication Date: 2013-08-15
    Description: In NW Scotland, several alkaline intrusive complexes of Silurian age intrude the Caledonian orogenic front. The most northerly is the Loch Loyal Syenite Complex, which is divided into three separate intrusions (Ben Loyal, Beinn Stumanadh and Cnoc nan Cuilean). Mapping of the Cnoc nan Cuilean intrusion shows two main zones: a Mixed Syenite Zone (MZ) and a Massive Leucosyenite Zone (LZ), with a gradational contact. The MZ forms a lopolith, with multiple syenitic lithologies, including early basic melasyenites and later felsic leucosyenites. Leucosyenite melts mixed and mingled with melasyenites, resulting in extreme heterogeneity within the MZ. Continued felsic magmatism resulted in formation of the relatively homogeneous LZ, invading western parts of the MZ and now forming the topographically highest terrane. The identification of pegmatites, microgranitic veins and unusual biotite-magnetite veins demonstrates the intrusion's complex petrogenesis. Cross-sections have been used to create a novel 3D GoCad™ model contributing to our understanding of the intrusion. The Loch Loyal Syenite Complex is known to have relatively high concentrations of rare earth elements (REEs), and thus the area has potential economic and strategic value. At Cnoc nan Cuilean, abundant REE-bearing allanite is present within melasyenites of the MZ. Extensive hydrothermal alteration of melasyenites here formed steeply dipping biotite-magnetite veins, most enriched in allanite and other REE-bearing accessories. This study has thus identified the area of greatest importance for further study of REE enrichment processes in the Cnoc nan Cuilean intrusion.
    Print ISSN: 0016-7568
    Electronic ISSN: 1469-5081
    Topics: Geosciences
    Published by Cambridge University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Horizontal convection dynamics: insights from transient adjustment (2013)
    Cambridge University Press
    Details
    Publication Date: 2013-06-11
    Description: The dynamics of horizontal convection are revealed by examining transient adjustment toward thermal equilibrium. We restrict attention to high Rayleigh numbers (of $O(1{0}^{12} )$) and a Prandtl number ${sim }5$ that characterize many practical applications, and consider responses to small changes in the thermal boundary conditions, using laboratory experiments, three-dimensional direct numerical simulations (DNS) and simple theoretical models. The experiments and the mechanical energy budget from the DNS demonstrate that unsteady forcing can produce flow dramatically more active than horizontal convection under steady forcing. The physical mechanisms at work are indicated by the time scales of approach to the new equilibrium, and we show that these can range over two orders of magnitude depending on the imposed change in boundary conditions. Changes that lead to a net destabilizing buoyancy flux give rapid adjustments: for applied heat flux conditions the whole of the circulation is controlled by conduction through the stable portion of the boundary layer, whereas for applied temperature difference the circulation is controlled by small-scale convection within the unstable part of the boundary layer. The experiments, DNS and models are in close agreement and show that the time scale under applied temperatures is as small as 0.01 vertical diffusion time scales, a factor of four smaller than for imposed flux. Both cases give adjustments too rapid for diffusion in the interior to play a significant role, at least through 99 % of the adjustment, and we conclude that diffusion through the full depth is not significant in setting the equilibrium state. Boundary changes leading to a net stabilizing buoyancy flux give a very different response, causing the convection to quickly form a shallow circulation cell, followed eventually by a return to full-depth overturning through a combination of penetrative convection and conduction. The time scale again varies by orders of magnitude, depending on the boundary conditions and the location of the imposed boundary perturbation. © 2013 Cambridge University Press.
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Cambridge University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Large-scale vortices in rapidly rotating Rayleigh–Bénard convection (2014)
    Cambridge University Press
    Details
    Publication Date: 2014-10-09
    Description: Using numerical simulations of rapidly rotating Boussinesq convection in a Cartesian box, we study the formation of long-lived, large-scale, depth-invariant coherent structures. These structures, which consist of concentrated cyclones, grow to the horizontal scale of the box, with velocities significantly larger than the convective motions. We vary the rotation rate, the thermal driving and the aspect ratio in order to determine the domain of existence of these large-scale vortices (LSV). We find that two conditions are required for their formation. First, the Rayleigh number, a measure of the thermal driving, must be several times its value at the linear onset of convection; this corresponds to Reynolds numbers, based on the convective velocity and the box depth, ≳100. Second, the rotational constraint on the convective structures must be strong. This requires that the local Rossby number, based on the convective velocity and the horizontal convective scale, ≲0.15. Simulations in which certain wavenumbers are artificially suppressed in spectral space suggest that the LSV are produced by the interactions of small-scale, depth-dependent convective motions. The presence of LSV significantly reduces the efficiency of the convective heat transport. © Cambridge University Press 2014.
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Cambridge University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    The effect of velocity shear on dynamo action due to rotating convection (2013)
    Cambridge University Press
    Details
    Publication Date: 2013-02-01
    Description: Recent numerical simulations of dynamo action resulting from rotating convection have revealed some serious problems in applying the standard picture of mean field electrodynamics at high values of the magnetic Reynolds number, and have thereby underlined the difficulties in large-scale magnetic field generation in this regime. Here we consider kinematic dynamo processes in a rotating convective layer of Boussinesq fluid with the additional influence of a large-scale horizontal velocity shear. Incorporating the shear flow enhances the dynamo growth rate and also leads to the generation of significant magnetic fields on large scales. By the technique of spectral filtering, we analyse the modes in the velocity that are principally responsible for dynamo action, and show that the magnetic field resulting from the full flow relies crucially on a range of scales in the velocity field. Filtering the flow to provide a true separation of scales between the shear and the convective flow also leads to dynamo action; however, the magnetic field in this case has a very different structure from that generated by the full velocity field. We also show that the nature of the dynamo action is broadly similar irrespective of whether the flow in the absence of shear can support dynamo action. © 2013 Cambridge University Press.
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Cambridge University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...