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  • 1
    Electronic Resource
    Electronic Resource
    A new nuclear magnetic resonance imaging technique for unambiguous unidirectional measurement of flow velocity (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 1256-1262 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A new nuclear magnetic resonance (NMR) flow-velocity-imaging method applied to the study of the fluid dynamics is introduced. In the proposed technique, a selection gradient is used for the phase encoding, and since the selection gradient is relatively small compared with the conventional gradient for phase encoding it allows the measurement of high-velocity flow. To obtain the phase-velocity relationship, the Bloch equation is solved numerically and establishes the quantitative phase-velocity relationship of the flow under the slice selection gradient and echo radio frequency pulse. The flow effect compensation in the directions other than the slice selection direction is achieved by applying additional flow coding gradients similar to the conventional flow phase coding. The experimental NMR flow images obtained with the new technique are compared with the velocity measurements made with a laser Doppler velocimeter, and are found to be in close agreement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337347
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Convergence of Galerkin solutions using Karhunen–Loève expansions of inhomogeneous 1-D turbulence (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 1695-1697 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The rate of convergence of the Karhunen–Loève expansion of an inhomogeneous, instantaneous random field is compared with that of Fourier expansion in relation to the Reynolds number. The model turbulence is generated by solving the Burgers' equation with random forcing. The coefficients of the Fourier expansion are determined by a Galerkin solution scheme. The results show obvious superiority of the Karhunen–Loève expansion, especially for high Reynolds number flows.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857948
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  • 3
    Electronic Resource
    Electronic Resource
    Approximation of turbulent conditional averages by stochastic estimation (1989)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 1 (1989), S. 992-998 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Conditional averages of turbulent flow quantities can be approximated in terms of unconditional correlation data by means of stochastic estimation. The validity and accuracy of this procedure are investigated by comparing stochastic estimates to conditional averages measured in four turbulent flows: grid turbulence, the axisymmetric shear layer of a round jet, a plane shear layer, and pipe flow. Comparisons are made for quantities that are separated from the conditional data in time or space, and for turbulent pressures, as well as turbulent velocities. In each case, the linear estimate accurately represents large scale structure. Nonlinear quadratic estimation shows little improvement over linear estimation, because the second-order terms are small for probable values of the turbulent fluctuations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857411
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  • 4
    Electronic Resource
    Electronic Resource
    A neutron diffraction study of potassium sulphamate, KSO3NH2 (1967)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 23 (1967), S. 578-581 
    Details
    ISSN: 0001-5520
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0365110X67003238
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  • 5
    Electronic Resource
    Electronic Resource
    Haematological Values During Normal Pregnancy in Sprague–Dawley Rats (2000)
    Springer
    Comparative clinical pathology 10 (2000), S. 74-79 
    Details
    ISSN: 1433-2981
    Keywords: Key words: Haematology; Historical control data; Pregnancy; Rat; Reproductive and developmental toxicity study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: The present study was undertaken to investigate changes in haematology parameters over the course of gestation in Sprague–Dawley rats. Blood samples were alternatively collected from two groups of pregnant rats on gestational days (GD) 0, 3, 6, 9, 12, 15, 18 and 21 using a needle catheter. Red blood cell counts, haemoglobin and haematocrit on GD 6, 12, 18 and 21 were lower than those of normal non-pregnant rats. These values declined progressively during the course of gestation and reached minimum levels on GD 18 or 21. There were no differences in mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration between pregnant and non-pregnant rats. Platelet counts in pregnant rats increased gradually with advancing gestation and were much higher on GD 15 and 21 than in nonpregnant rats. Total white blood cell and lymphocyte counts on GD 0–15 were higher than those of non-pregnant rats. These values increased maximally by GD 6 and then decreased progressively to a nadir on GD 21. Neutrophil counts on GD 9–21 were higher than non-pregnant rat values. The neutrophils increased to a peak level on GD 12 and then steadily decreased. These data can be used not only as a historical database for the effective evaluation of data from reproductive toxicology studies, but also as a contribution to biological characterisation of Sprague–Dawley rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005800070011
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of surface roughness on a turbulent wall-attaching offset jet (1995)
    Springer
    Experiments in fluids 19 (1995), S. 38-42 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The flow characteristics of a two-dimensional offset jet discharged parallel to a rough wall is experimentally investigated by using a split film probe. The distributions of the mean velocity and turbulent stresses in the flow field are obtained and compared with those of the wall attaching offset jet on a smooth wall. It is found that the wall-attaching region on the rough wall is longer than on the smooth wall for the same offset height and the jet speed. The normal distance of the maximum velocity point is farther away from the wall than that for the smooth wall case because of the thick wall boundary layer established by the surface roughness. It is also found that the roughness of the wall accelerates the relaxation process towards redeveloped plane wall jet and that it exhibits a quite different turbulent diffusion behavior especially near the wall from that in the wall jet over a smooth surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192231
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  • 7
    Electronic Resource
    Electronic Resource
    The evolution of initially uniform shear flow through a nearly two-dimensional 90° curved duct (1995)
    Springer
    Experiments in fluids 19 (1995), S. 173-187 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An experimental study has been made in a nearly two-dimensional 90° curved duct to investigate the effects of interaction between streamline curvature and mean strain on the evolution of turbulence. The initial uniform shear at the entrance to the curved duct was varied by an upstream shear generator to produce five different shear conditions; a uniform flow (UF), a positive weak shear (PW), a positive strong shear (PS), a negative weak shear (NW) and a negative strong shear (NS). The variations of surface pressure and the mean velocity profiles along the downstream direction under different initial shears are carefully measured. The responses of turbulent Reynolds stresses and triple velocity products to the curvature and the mean strain are also investigated. The evolution of turbulence under the curvature with the different shear conditions is described in terms of the turbulent kinetic energy and the various length scales vs the angular distance θ or a curvature parameters S c which is defined by S c = (U/R)/(dU/dy- U/R). The results show that the turbulent kinetic energy and the integral length scale are augmented when S c 〈 0.054 whereas they are suppressed when S c 〉 0.054. It is also observed that the micro-length scales of Taylor and Kolmogoroff are relatively insensitive to the curvature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189706
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  • 8
    Electronic Resource
    Electronic Resource
    Experimental study of thermally stratified unsteady flow by NMR-CT (1987)
    Springer
    Experiments in fluids 5 (1987), S. 273-281 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Thermally stratified unsteady flow caused by two-dimensional surface discharge of warm water into a rectangular reservoir is investigated. Experimental study is focused on the rapidly developing thermal diffusion at small Richardson number. The basic objectives are to develop a measurement system for the unsteady flow phenomena and to study the interfacial mixing between a flowing layer of warm water and the underlying body of cold water. Mean velocity field measurement is carried out by using NMR-CT (Nuclear Magnetic Resonance — Computerized Tomography). It detects a quantitative flow image of any desired section in any direction of flow. Transient mean temperature profiles are obtained by fine thermocouple arrays and a microcomputer-based data acquisition system. Results show that the warm layer penetrates more rapidly into the cold layer at smaller Richardson number because of decrease instability. This is clearly verified by flow visualization using thymol blue solution. It is found that the transport of heat across the interface is more vigorous than that of momentum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00279742
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