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  • 1
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 2400-2402 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A permanent magnet (spherical shape, radius 100 μm) is levitating inside a superconducting parallel plate capacitor made of YBCO. Translational oscillations of the magnet at its resonance frequency (∼150 Hz) can be excited and detected. The damping of the oscillations is investigated as a function of temperature and oscillation amplitude. Close to Tc we observe a steep minimum of the damping. The data can be described by a linear frictional force which decreases near Tc, and a quadratic one which diverges at Tc. These frictional forces are attributed to flux flow phenomena in the high-Tc superconductor. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 375 (1995), S. 286-286 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - Beck et al.1 have reported new bio-geographical data, concluding that the collision of the Indian subcontinent with Asia was older than previously claimed. They suggested that the collision occurred between 66 and 55.5 Myr (million years) ago. However, palaeontological ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archive of applied mechanics 65 (1995), S. 478-487 
    ISSN: 1432-0681
    Keywords: Key words Contact problem of elasticity ; superposition ; flat punch solutions ; annular sliding ; stick area.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary  Two axi-symmetric bodies are pressed together, so that their axes of symmetry coincide with the contact normal and the normal force is held constant. A small torque about the contact normal or a small tangential force is applied. For bodies of equal material, the normal and tangential stress states are uncoupled, and can be solved separately. The surfaces of the bodies are thought as a superposition of infinitesimal rigid flat-ended punches. Consequently, the normal stress distribution can be calculated as a summation of differential flat punch solutions. A formula results, which is identical with the solution of Green and Collins. After application of a torque an annular sliding area forms at the border of the contact area. For reasons of symmetry, the common displacement of the inner stick area must be a rigid body rotation. Similarly to the normal problem, the solution can be thought as a superposition of rigid punch rotations. The tangential solution can be derived analogically, in form of a superposition of rigid punch displacements. The present method also solves the problem of simultaneous normal and torsional or tangential loading with complete adhesion. As an example, Steuermann’s problem for polynomial surfaces of the form A 2 n r2 n is solved. The solutions for constant normal forces can be used as basic functions for loading histories with varying normal and tangential forces.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Archive of applied mechanics 69 (1999), S. 181-203 
    ISSN: 1432-0681
    Keywords: Key words granular material ; generalized Hertz contact ; elastic friction ; nonlinear elasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Mechanical behavior of dense packing spheres with small irregularities is investigated in this paper. A generalization of the hertzian contact model for surfaces of the form x k yields a normal contact force F n , which is proportional to ζ1+1/ k , with the normal displacement ζ. For oblique forces, the frictional force can be calculated, [10]. Different load cases are explained in detail. It is shown that the stress-strain curve during initial loading of the packing is identical with the force-displacement relation at the contact point, using an appropriate constant. The results for uniaxial loading, unloading and reloading are illustrated. As experimentally observed, the axial pressure in unloading is smaller than during loading, while the lateral pressure increases. The stress-strain relation is compared with well-known empirical relations of rock and soil mechanics, and the wave velocity for spherical irregularities agrees with earlier geomechanical theories for random packing of smooth spheres.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Archive of applied mechanics 67 (1997), S. 247-259 
    ISSN: 1432-0681
    Keywords: Key words uncoupled contact ; plane elasticity ; Cattaneo-Mindlin principle ; elastic friction ; singular integrals.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Nonrotating half-planes in contact under oblique loading are investigated in this paper. The solution is based on the influence integrals of the Flamant solution. The problem is determined by two integral equations for the normal and tangential stresses, which are uncoupled for special cases, as bodies of similar material in contact. In order to simplify the singular integrals, the method of superposition of flat punches is used. The result for the symmetric case is almost identical with the axisymmetric solution. For polynomial profiles of the form x s , the Muskhelishvili potentials can be written in terms of a complex hypergeometric function. The interior stress field is illustrated for an example.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Archive of applied mechanics 65 (1995), S. 478-487 
    ISSN: 1432-0681
    Keywords: Contact problem of elasticity ; superposition ; flat punch solutions ; annular sliding ; stick area
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Two axi-symmetric bodies are pressed together, so that their axes of symmetry coincide with the contact normal and the normal force is held constant. A small torque about the contact normal or a small tangential force is applied. For bodies of equal material, the normal and tangential stress states are uncoupled, and can solved separately. The surfaces of the bodies are thought as a superposition of infinitesimal rigid flat-ended punches. Consequently, the normal stress distribution can be calculated as a summation of differential flat punch solutions. A formula results, which is identical with the solution of Green and Collins. After application of a torque an annular sliding area forms at the border of the contact area. For reasons of symmetry, the common displacement of the inner stick area must be a rigid body rotation. Similarly to the normal problem, the solution can be thought as a superposition of rigid punch rotations. The tangential solution can be derived analogically, in form of a superposition of rigid punch displacements. The present method also solves the problem of simultanous normal and torsional or tangential loading with complete adhesion. As an example, Steuermann's problem for polynomial surfaces of the formA 2nr2nis solved. The solutions for constant normal forces can be used as basic functions for loading histories with varying normal and tangential forces.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Der Gynäkologe 31 (1998), S. 283-286 
    ISSN: 1433-0393
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zum Thema Höhergradige Mehrlingsgeburten werden häufiger als früher registriert; so wurden 1995 in Deutschland 280 Schwangere von Drillingen entbunden. Die opportunistischen sozioökonomischen Probleme der Familien mit Mehrlingen werden von Laien wie von Fachleuten erheblich unterschätzt. Daher wurde retrospektiv mittels Fragebogen die sozioökonomische Situation von 103 der 308 Familien mit komplett überlebenden Drillingen (Stichprobe) und von allen 35 Familien mit komplett überlebenden Vierlingen untersucht. Die Rücklaufquote betrug 79,7 % (n = 83 von 103 Drillingen, n = 27 von 35 Vierlingen). Das mütterliche Durchschnittsalter bei der Geburt betrug 29 Jahre, das mittlere Alter der Väter lag bei 35 Jahren; 32 der 83 der auswertbaren Drillingsgraviditäten waren spontan empfangen worden, die restlichen Drillinge sowie alle Vierlinge nach Sterilitätsbehandlung. Die durchschnittliche Schwangerschaftsdauer betrug 35,2 bzw. 32,2 Wochen für Drillinge respektive Vierlinge. Die Kinderzahl betrug 3, 4, 5 oder 6 bei 44, 41, 23 bzw. 2 Familien (im Mittel 3,85); 84 % der Mütter wurden nicht wieder berufstätig. Ihre körperliche Verfassung bezeichneten nur 24 als gut. Eine normal lange Nachtruhe von mehr als 7 h Dauer erreichten nur 1 Drillings- und 2 Vierlingsmütter sowie 11 bzw. 5 der Väter. Ihre Kinder konnten nur 5 Eltern mit einem geringsten Aufwand von 6–10 h pro Tag versorgen. Die “Freizeit“ von 99 Müttern betrug 0–1 h pro Tag. Das Familiennettoeinkommen von 74 bzw. 85 % der Mehrlingsfamilien lag unter 5.000 oder 6.000 DM/Monat. In 23 Familien war mindestens eines der Mehrlingskinder behindert (20,9 %); die Gesamtzahl der behinderten Kinder betrug 34. Krankengymnastisch mußten insgesamt 80 Mehrlingskinder von 60 Familien behandelt werden. Da 78 der 110 untersuchten höhergradigen Mehrlingsschwangerschaften unter Sterilitätsbehandlung eingetreten waren, stellt die Prävention der iatrogenen Mehrlingskonzeption eine aktuelle professionelle Herausforderung dar.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Knee surgery, sports traumatology, arthroscopy 4 (1996), S. 92-96 
    ISSN: 1433-7347
    Keywords: Patellofemoral pain ; Maquet procedure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Sports Science
    Description / Table of Contents: Resumé 100 patients opérés d'un avancement de la tubérosité tibiale antéricure selon Maquet ont été réexaminés avec un recul moyen de quatre ans, et 65 d'entre cux ont pu être réexaminés ultérieurement avec un recul moyen de onze ans (extrêmes de huit à quinze ans). L'intensité de la douleur a été significativement diminuée après l'intervention et cette amélioration est restée stable dans le temps. Mais globalement le taux de succès n'était que de 62% à chacun des deux examens. La présence à l'intervention d'une mise à nu de l'os sous-chondral était significativement associée à un meilleur résultat antalgique, avec un taux de succès de 69%. L'intervention de Maquet ne doit être proposée que pour un syndrome douloureux fémoropatellaire avec mise à nu de l'os sous-chondral, mais l'indication doit être prudente car le taux d'échec est élevé.
    Notes: Abstract One hundred patients were operated on by the Maquet procedure for chondromalacia patellae. All of them were first re-examined after a mean follow-up of 4 years, and 65 of them re-examined after a mean follow-up of 11 years (range, 8–15 years). The pain score improved significantly after the operation and remained unchanged with longer follow-up. The success rate was only 62% at both follow-ups. Outerbridge grade IV chondral lesions at the time of surgery were associated with a significant improvement of the pain score at the 4-year follow-up and a success rate of 69%. The Maquet procedure should only be proposed for chronic retropatellar pain with grade IV chondral lesions. after conservative treatment has proven unsuccessful, as the expected failure rate is about 30%.
    Type of Medium: Electronic Resource
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