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  • Articles  (6)
  • Anisotropy  (3)
  • heat transfer  (3)
  • Springer  (6)
  • American Geophysical Union (AGU)
  • Annual Reviews
  • Wiley
  • 1980-1984  (6)
  • 1935-1939
  • Technology  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Effect of the Knudsen number on heat transfer to a particle immersed into a thermal plasma (1983)
    Springer
    Plasma chemistry and plasma processing 3 (1983), S. 97-113 
    Details
    ISSN: 1572-8986
    Keywords: Knudsen effect ; heat transfer ; small particles ; thermal plasmas ; analytical studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The Knudsen effect on heat transfer to a particle exposed to a thermal plasma is important for many practical situations experienced in plasma chemistry and plasma processing. This paper provides theoretical results of this effect based on the “heat conduction potential jump” approach. It is shown that a correction factor which depends on the Knudsen number must be introduced into the expressions for heat fluxes obtained previously based on the continuum approach. The Knudsen effect is stronger for smaller particles and it is also more pronounced for an Ar-H2 plasma (compared to Ar and nitrogen plasmas at the same temperature). Since the Knudsen effect depends on the surface temperature of a particle, calculation of particle heating becomes more complicated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566030
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  • 2
    Electronic Resource
    Electronic Resource
    Operating characteristics and energy distribution in transferred plasma arc systems (1982)
    Springer
    Plasma chemistry and plasma processing 2 (1982), S. 361-386 
    Details
    ISSN: 1572-8986
    Keywords: Transferred arc ; characteristics ; heat transfer ; experimental
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract A specially designed plasma chamber was constructed to study the operating characteristics of a dc plasma-transferred arc of argon, struck between a fluid convective cathode and a water-cooled anode. The arc voltage increased markedly with arc length and with an increase in the inlet velocity of the argon flow past the cathode tip, and much less with an increase in current. Radiation from the plasma column to the chamber walls and transfer of energy to the anode were the two principal modes of transfer of the arc energy. The former was dominant in the case of long arcs and at high inlet argon velocities. At the anode, the major contribution was from electron transfer, which occurred on a very small area of the anode (∼5 mm in diameter). Convective heat transfer from the plasma was somewhat less. In all cases, the arc energy contributions to cathode cooling and to the exit gas enthalpy were small. From total heat flux and radiative heat transfer measurements, it was estimated that the plasma temperature just above the anode was in the range 10,000–12,000 K. Preliminary experiments with an anode consisting of molten copper showed that the arc root was no longer fixed but moved around continuously. The arc was othwewise quite stable, and its operating characteristics differed little from those reported for solid anodes, in spite of the greater extent of metal vaporization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00567563
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  • 3
    Electronic Resource
    Electronic Resource
    Mechanical behavior of vascular smooth muscle in cylindrical segments of arteries in vitro (1984)
    Springer
    Annals of biomedical engineering 12 (1984), S. 497-510 
    Details
    ISSN: 1573-9686
    Keywords: Passive mechanics ; Active stress ; Active constriction ; Elastic modulus ; Series elastic element ; Anisotropy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Vascular smooth muscle mechanics have been studied in vitro in cylindrical segments of dog carotid artery, human internal mammary artery, and human saphenous vein. Such cylindrical preparations maintain normal vessel geometry and also permit correlation of mechanical phenomena with transmural pressure. These studies show that the vascular muscle in cylindrical arteries develops a maximum active stress of 1.1×105 N/m2 for the whole wall, or 2.2–3.7×105 N/m2 for the volume of the wall occupied by vascular muscle. These values are similar to those reported for strip studies of vascular muscle and various preparations of skeletal muscle, but are two to five times that reported for cardiac papillary muscle preparations. In cylindrical preparations of arteries, maximum isometric active stress occurs at 150 mm Hg, whereas that in veins occurs at less than 15 mm Hg. Quick release experiments of cylindrical segments of vessels avoid the compliance of inactive tissue trapped beneath ligatures in strip studies. Quick release experiments in cylindrical segments of dog carotid artery reveal that at maximum isometric stress, the series elastic component (SEC) is extended 8–11%. Experiments employing temperature variations and degradative enzymes show that the SEC is located largely in elastin, with a lesser portion located in the contractile apparatus. At short-and long-muscle lengths, the active muscle develops decreased active stress and that developed at long lengths persists at all muscle lengths, even after shortening. This has been termed “attenuation” and appears to contribute to the static length-stress and pressure-diameter hysteresis exhibited by vessels. Excitation of vascular muscle in vessel segments held at constant pressure discloses that isobaric contraction decreases artery diameter a maximum of approximately 25%. This occurs at a dimension corresponding to approximately 100 mm Hg in the relaxed vessel. Isometrically and isobarically contracted vessels tend to fall along the same pressure-diameter coordinates, indicating equivalence of both modes of contraction. Distention of contracted vessels indicates that active vascular muscle markedly resists distention up to 150–250 mm Hg; at higher pressures the contracted vessel exhibits decreased stiffness as the contracted muscle yields. The vascular muscle, therefore, has a biphasic effect on circumferential elastic modulus relative to that of the relaxed vessel. Although controversial, evaluation of the effects of the active muscle on wall elastic modulus probably is most meaningful when the modulus is examined as a function of stress, or as a function of strain, where strain is computed with respect to a single initial dimension for both the relaxed and contracted vessel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02363919
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  • 4
    Electronic Resource
    Electronic Resource
    The discontinuous nature of electrical propagation in cardiac muscle (1983)
    Springer
    Annals of biomedical engineering 11 (1983), S. 208-261 
    Details
    ISSN: 1573-9686
    Keywords: Anisotropy ; Cell-to-cell coupling ; Continuous cable theory ; Discontinuities of axial resistivity ; Discontinuous propagation ; Hodgkin-Huxley equations ; Numerical analysis ; Propagation models ; Propagation of depolarization ; Safety factor of propagation ; Velocity,V max
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The propagation of excitation in cardiac muscle has generally been treated as though it occurred in a continuous structure. However, new evidence indicates that propagation in cardiac muscle often displays a discontinuous nature. In this paper, we consider the hypothesis that this previously unrecognized type of propagation is caused by recurrent discontinuities of effective axial resistivity which affect the membrane currents. The major implication is that the combination of discontinuities of axial resistivity at several size scales can produce most currently known cardiac conduction disturbances previously thought to require spatial nonuniformities of the membrane properties. At present there is no appropriate model or simulation for propagation in anisotropic cardiac muscle. However, the recent quantitative description of the fast sodium current in voltage-clamped cardiac muscle membrane makes it possible, for the first time, to apply experimentally based quantitative membrane models to propagation in cardiac muscle. The major task now is to account for the functional role of the structural complexities of cardiac muscle. The importance of such a model is that it would establish how the membrane ionic currents and the complexities of cell and tissue structure interact to determine propagation in both normal and abnormal cardiac muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02363287
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  • 5
    Electronic Resource
    Electronic Resource
    Behavior of small particles in a thermal plasma flow (1983)
    Springer
    Plasma chemistry and plasma processing 3 (1983), S. 351-366 
    Details
    ISSN: 1572-8986
    Keywords: Small particles ; heat transfer ; drag ; Knudsen effect ; convection ; thermal plasma ; computation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract In this paper computational results are presented which reveal the effects of the Knudsen number on heat transfer and drag of small particles in a flowing thermal argon plasma. The Knudsen number is restricted to moderate values so that “temperature jump” and “velocity slip” conditions may be employed, and for the governing equations the continuum approach remains valid. It is shown that the ratio of the heat fluxes with and without the Knudsen effect is almost identical to the ratio obtained by the authors for the case of pure heat conduction. This fact is very important for modeling of the behavior of particles injected into an actual plasma reactor when the Knudsen effect has to be taken into account.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00564633
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  • 6
    Electronic Resource
    Electronic Resource
    A bidomain model for anisotropic cardiac muscle (1983)
    Springer
    Annals of biomedical engineering 11 (1983), S. 191-206 
    Details
    ISSN: 1573-9686
    Keywords: Electrocardiogram ; Bidomain model ; Heart muscle ; Magnetocardiogram ; Anisotropy ; Model study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Cardiac muscle is considered to consist of an intracellular domain and an exracellular or interstitial domain. Current passes from one domain to the other through the cell membrane. Electric potentials in interstitial space are shown to be associated with current sources proportional to the spatial gradient of the cellular transmembrane action potential, φ m . Hence, given the distribution of φ m throughout the myocardium, one can calculate the surface electrocardiogram and extracorporeal magnetocardiogram. The problem is considerably complicated when anisotropy is considered. If interstitial space is approximately isotropic, however, the sources are still proportional to ∇φ m . It is shown that the effects of intracellular anisotropy on the surface electrocardiogram may be relatively small. The inverse problem is discussed briefly, with consideration of the relationship of the magnetocardiogram to the electrocardiogram. Finally, it is shown that if the heart can be considered to be bounded by a closed surface, then the value of φ m on this surface is uniquely related to the surface electrocardiogram to within a constant, provided there are no internal discontinuities. Such discontinuities, however, would be expected to occur in cases of ischemia and necrosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02363286
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