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  • Springer  (12)
  • Wiley-Blackwell  (4)
  • 2000-2004  (1)
  • 1970-1974  (11)
  • 1955-1959  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Wave propagation aspects of the generalized theory of heat conduction (1972)
    Springer
    Zeitschrift für angewandte Mathematik und Physik 23 (1972), S. 927-940 
    Details
    ISSN: 1420-9039
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Description / Table of Contents: Zusammenfassung Bekanntlich führt Fourier's klassische Theorie der Wärmeleitfähigkeit zu einer unendlich großen Ausbreitungsgeschwindigkeit lokaler Temperaturstörungen. Gurtin und Pipkin haben eine Theorie für starre Wärmeleiter mit Gedächtnis eingeführt und haben auch einen Beweis dafür gegeben, daß ihre Theorie auf eine endliche Ausbreitungsgeschwindigkeit führt. Die vorliegende Arbeit bezieht sich auf die linearisierte Form der Theorie von Gurtin und Pipkin für isotrope Leiter. Es werden Bedingungen für endliche Ausbreitungsgeschwindigkeit angegeben. Ferner wird die Eindeutigkeit der Lösungen für eine Klasse von history-value-Problemen angegeben, die durch die lineare Theorie nahegelegt werden.
    Notes: Summary It is well known that the classical theory of heat conduction, which is based upon Fourier's law, leads to infinite propagation speeds for thermal disturbances. In a recent investigation [1], Gurtin and Pipkin devised a theory appropriate to rigid heat conductors with memory, and put forth evidence that their theory gives rise in general to finite wave speeds. The present paper is concerned with the linearized version of the theory presented in [1], in the form it assumes for isotropic conductors. We arrive at conditions upon the material response functions that ensure the finiteness of the wave speeds. In addition, we establish uniqueness of solutions for a class of history-value problems suggested by the linearized theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01596220
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  • 2
    Electronic Resource
    Electronic Resource
    An ant counter and its use in the field (1972)
    Springer
    Entomologia experimentalis et applicata 15 (1972), S. 499-508 
    Details
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Cet appareil portatif est utilisé pour dénombrer les fourmis coupeuses de feuilles (Attinae) ou les fragments qu'elles transportent, le long de leurs trajets dans les cultures ou les forêts tropicales. Il utilise une batterie de 12 volts comme source de puissance. Les fourmis sont amenées à passer sous un portique placé sur leur trajet, interceptant alors un faisceau lumineux entre la source et une cellule photo-électrique. Le portique fait de structures mêtalliques creuses et comportant une rampe d'accès en cuivre peut enjamber une piste de fourmis de 20 cms de large; les détails de sa construction sont donnés Fig. 1 et 2. Le circuit électronique à l'intérieur de la boîte de contrôle (Fig. 3) est arrangé de telle sorte qu'aucun courant ne passe tant qu'aucune fourmi ne traverse le faisceau lumineux entre la source et la cellule photo-électrique; c'est seulement lorsqu'une fourmi intercepte ce faisceau lumineux que le relais et le compteur sont mis en circuit. Le compteur permet la distinction entre une fourmi chargée et une fourmi sans fardeau, d'après la hauteur à laquelle la rampe d'accès et de passage sous le portique est ajustée par rapport au faisceau de lumière. L'efficacité du comptage dépend de l'espèce de fourmi et des caractéristiques de la partie du végétal qui est coupée et transportée (Fig. 4). Les causes habituelles d'erreurs qui peuvent se présenter pour les observations à l'extérieur sont passées en revue et des indications sont fournies en vue de les éviter. Un compteur enregistreur sur papier capable de détecter et enregistrer les fourmis passant à un rythme allant jusqu'à 250/minute pendant des intervalles de 15 minutes à 24 heures est également décrit. Pour réduire la consommation de papier enregistreur, un dispositif réducteur est fixé en avant du compteur de façon que ce dernier n'enregistre que tous les 10, 100 ou 1000 passages. En utilisant un déroulement du papier à la vitesse de 2,5 cms par heure, le compteur travaille sans arrêt pendant 3 jours. Le dispositif peut être modifié par compter d'autres insectes qui se déplacent habituellement le long des trajets bien définis.
    Notes: Abstract This portable ant counter counts foraging leafcutting ants, or the leaf fragments they carry, along trails in tropical crops or forest. Ants intercept a light beam as they pass under a gantry between the light source and a photocell. The counter distinguishes between laden and unladen ants and works with an efficiency of 10–120% depending on the species of ant and the characteristics of the vegetation cut. The design could be modified to count other insects that habitually walk along well-defined tracks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293614
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  • 3
    Electronic Resource
    Electronic Resource
    A comparison of water traps, cylindrical sticky traps and suction traps for sampling thysanopteran populations at different levels (1959)
    Springer
    Entomologia experimentalis et applicata 2 (1959), S. 204-215 
    Details
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Sommaire Les Thysanoptères qui flottaient autour et au-dessus d'un champ de blé étaient attrapés par le moyen de pièges à l'eau noirs, verts ou blancs, de pièges cylindriques qui étaient visqueuz et noirs et d'aspirateurs. De certaines espèces des genres Taeniothrips, Thrips et Aeolothrips étaient très attirées par le blanc mais pas par le vert ni le noir: les espèces Limothrips cerealium Hal., Chirothrips manicatus Hal., et Stenothrips gramium Uzel n'étaient pas notablement attirées par chacune de ces couleurs. Au niveau des épis les données obtenues avec les aspirateurs étaient plus justes que ne l'étaient celles obtenues avec les pièges à glu ou les pièges à eau: plus haut les pièges à glu indiquaient des données plus justes que les pièges à eau. Jusqu'à quinze mètres environ de hauteur la densité aérienne de toutes les espèces diminuaient progressivement, mais la rapidité de la diminution était différente entre les espèces.
    Notes: Abstract Thysanoptera drifting over and around a wheat field were trapped using black, green and white water traps, black cylindrical sticky traps and suction traps. Certain Taeniothrips spp., Thrips spp., and Aeolothrips spp. were strongly attracted to white but not to green or black; Limothrips cerealium Hal., Chirothrips manicatus Hal., and Stenothrips gramium Uzel were not markedly attracted to any of these colours. At crop level suction traps gave more consistent catches2 than either sticky or water traps; at higher levels, catches from sticky traps were more consistent than those from water traps. Up to 48 ft the aerial density of all species decreased with height but the rapidity of the decrease differed between species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302539
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  • 4
    Electronic Resource
    Electronic Resource
    Book reviews (1973)
    Springer
    Entomologia experimentalis et applicata 16 (1973), S. 137-140 
    Details
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333559
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  • 5
    Electronic Resource
    Electronic Resource
    The annual cycle of Limothrips cerealium haliday (Thysanoptera) and its distribution in a wheat field (1959)
    Springer
    Entomologia experimentalis et applicata 2 (1959), S. 187-203 
    Details
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Sommaire Les populations terrestres et aériennes de l'espèce L. cerealium (Thysanoptères) étaient étudiées simultanément: des dissections ovariques étaient faites pour discerner les générations différentes. On peut arbitrairement diviser la vie de ces insectes en six périodes, basées principalement sur l'activité aérienne: au printemps les femelles se nourrissent pour la plupart d'herbes et de céréales d'hiver; en juin et juillet beaucoup d'elles passent sur les céréales de printemps, où elles pondent la plupart des oeufs dans les gaines des jeunes feuilles. Les femelles de la première génération laissent les céréales en aôut pour se nourrir d'herbes avant d'hiverner. Les Thysanoptères abandonnaient les épis dont la teneur en eau était approximativement moins de quarante-cinq pour cent. Quand le vent soufflait constamment du même côté l'infestation initiale était plus forte au bord du champ qui se trouvait exposé au vent.
    Notes: Abstract Terrestrial and aerial populations of L. cerealium were studied simultaneously; ovarian dissections were made to detect different generations. The annual life cycle can be arbitrarily divided into six stages based primarily on the amount of flight activity: the females feed mainly on winter cereals and grasses in spring, many moving to later sown cereals in June and July, where most eggs are laid in the sheaths of the young leaves. First generation females leave cereals in August to feed on grasses before entering hibernation. Wheat ears with a water content of less that approx. 45% were not favoured by thrips. When winds blew consistently from the same quarter the initial infestation was greatest on the windward edge of the wheat crop.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302538
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  • 6
    Electronic Resource
    Electronic Resource
    Apparent compensation in the electrical conductivity of polycrystalline isocytosine (1972)
    Springer
    Journal of bioenergetics and biomembranes 3 (1972), S. 245-248 
    Details
    ISSN: 1573-6881
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Values for the activation energy and pre-exponential factor from electrical conductivity measurements on polycrystalline isocytosine were found to be reproducible when evaporated electrodes were used. With pressure contacts a linear relationship exists between activation energy and the logarithm of the pre-exponential factor. This is shown to be an apparent and not a true compensation effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01515972
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  • 7
    Electronic Resource
    Electronic Resource
    Geiger-counter operation without dead-time (1956)
    Springer
    Flow, turbulence and combustion 5 (1956), S. 305-308 
    Details
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The dead timeΤ of a Geiger counter can be completely overcome by operating the counter with a pulsed voltage. The theory of the method is developed for two modes of measurement and simple formulae are derived. Even withΤ=100Μs, accurate counting is possible when the rate of arrival of particles at the counter is as high as 106/s.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02070015
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  • 8
    Electronic Resource
    Electronic Resource
    A curved cubic triangular finite element for potential flow problems (1973)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 7 (1973), S. 337-344 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A curved cubic triangular element which has as nodal parameters the value of the function and its two derivatives is derived by use of a transformation similar to that used for quadrilateral isoparametric elements. A special form of the element which may be used to satisfy the condition that the function is constant along a boundary is also presented.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620070310
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  • 9
    Electronic Resource
    Electronic Resource
    Dynamic mechanical properties of particulate-filled composites (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 14 (1970), S. 1449-1471 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The relative shear moduli of composites containing glass spheres in a rubbery matrix obey the Mooney equation, analogous to the relative viscosity of similar suspensions in Newtonian liquids. However, when the matrix is a rigid epoxy, the relative shear moduli are less than what the Mooney equation predicts but greater than what the Kerner equation predicts. Relative moduli are less for rigid matrices than for rubbery matrices because (1) the modulus of the filler is not extremely greater compared to that of the rigid matrix; (2) Poisson's ratio is less than 0.5 for a rigid matrix; (3) thermal stresses in the matrix surrounding the particles reduce the apparent modulus of the polymer matrix because of the nonlinear stress - strain behavior of the matrix. This latter effect gives rise to a temperature dependence of the relative modulus below the glass transition temperature of the polymer matrix. Formation of strong aggregates increases the shear modulus the same as viscosity is increased by aggregation. Torsion or flexure tests on specimens made by casting or by molding give incorrect low values of moduli because of a surface layer containing an excess of matrix material; this gives rise to a fictitious increase in apparent modulus as particle size decreases. The mechanical damping can be markedly changed by surface treatment of the filler particles without noticeable changes in the modulus. The Kerner equation, which is a lower bound to the shear modulus, is modified and brought into closer aggrement with the experimental data by taking into account the maximum packing fraction of the filler particles.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1970.070140604
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  • 10
    Electronic Resource
    Electronic Resource
    On wave propagation and uniqueness in one-dimensional elastic bodies (1973)
    Springer
    Journal of elasticity 3 (1973), S. 141-146 
    Details
    ISSN: 1573-2681
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Ein Begriff, bezeichnet als Wellenfortpflanzungseigenschaft, wird in Zusammenhang mit der nicht-linearen Theorie des eindimensionalen elastischen Körpers untersucht. Ein Körper besitzt, gross gesprochen, diese Eigenschaft, wenn sich mechanische Störungen mit beschränkter Geschwindigkeit fortpflanzen. Mit Hilfe des Ergebnisses für Wellenfortpflanzung wird ein Eindeutigkeitsatz bewiesen.
    Notes: Abstract A notion referred to as the Wave Propagation Property is analyzed in the context of the nonlinear theory of one-dimensional elastic bodies. Roughly speaking, a body possesses this property if mechanical disturbances propagate with bounded speed. A uniqueness theorem is proven with the aid of the results on wave propagation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00045820
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