Axially symmetric thermal-stress distribution in an infinite elastic solid containing an annular crack under torsion

Summary In the present work the axially symmetric thermal-stress distribution in an infinite elastic solid containing an annular crack under torsion has been studied. The problem is reduced to triple integral equations which in their turn are reduced to simultaneous algebraic equations by using Hankel transform technique. The quantities of physical interest have also been computed and illustrated graphically for different values of the inner and outer radius of the crack.

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Riassunto In questo lavoro si studia la distribuzione a simmetria assiale dello stress termico in un solido elastico infinito che contiene un crack annulare sotto torsione. Il problema è ridotto alle equazioni integrali triple che per contro sono ridotte ad equazioni algebriche simul tanee usando la tecnica di trasformazione di Hankel. Sono state calcolate ed illustrate graficamente per valori differenti del raggio interno ed esterno del crack anche le quantità di interesse fisico.

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Резюме В работе исследуется аксиально симметричное распределение термических напряжений в бесконечном упрутом твердом теле, содержащем кольцевые трещины при кручении. Рассматриваемая проблема сводится к интегральным уравнениям с тройными интегралами, которые, в свою очередь, сводятся к совместным алгебраическим уравнениям, испрльзуя технику преобразований Ганкеля. Вычисляются величины, представляющие физический интерес. Полученные величины иллюстрируются графически для различных значений внутреннего и внешнего радиусов трещин.

     

Supersymmetric classical mechanics

The purpose of the paper is to construct a supersymmetric Lagrangian within the framework of classical mechanics which would be regarded as a candidate for passage to supersymmetric quantum mechanics. The authors felicitate Prof. D S Kothari on his eightieth birthday and dedicate this paper to him on this occasion.     

Acidity and aniline alkylation activity of mixed Fe-Al pillared montmorillonites

Al-pillared, Fe-pillared and mixed Fe-Al pillared systems have been prepared and characterized using EDX and XRD analyses, surface area pore volume and acidity measurements. Mixed systems are found to be superior to single oxide pillared systems in terms of acidity and aniline methylation activity. This revised version was published online in June 2006 with corrections to the Cover Date.     

Recovery of Band-Limited Functions on Locally Compact Abelian Groups from Irregular Samples

Using the techniques of approximation and factorization of convolution operators we study the problem of irregular sampling of band-limited functions on a locally compact Abelian group G. The results of this paper relate to earlier work by Feichtinger and Gröchenig in a similar way as Kluvánek's work published in 1969 relates to the classical Shannon Sampling Theorem. Generally speaking we claim that reconstruction is possible as long as there is sufficient high sampling density. Moreover, the iterative reconstruction algorithms apply simultaneously to families of Banach spaces.     

Persistent currents in mesoscopic rings and conformal invariance

The effect of point defects on persistent currents in mesoscopic rings is studied in a simple tight-binding model. Using an analogy with the treatment of the critical quantum Ising chain with defects, conformal invariance techniques are employed to relate the persistent current amplitude to the Hamiltonian spectrum just above the Fermi energy. From this, the dependence of the current on the magnetic flux is found exactly for a ring with one or two point defects. The effect of an aperiodic modulation of the ring, generated through a binary substitution sequence, on the persistent current is also studied. The flux-dependence of the current is found to vary remarkably between the Fibonacci and the Thue-Morse sequences. Received: 4 March 1998 / Revised: 20 April 1998 / Accepted: 30 April 1998     

爆炸力学数值模拟中本构建模问题的讨论

就爆炸力学数值模拟中的本构建模问题的有关内容作了讨论,包括:波传播研究与材料的动态特性研究的相互依赖、容变律与畸变律的解耦与耦合、率型本构关系与失效准则、应变率效应与温度效应的等效性、加载本构关系与卸载本构关系以及流变过程与损伤演化过程的耦合等,并展望了今后的有关发展动向。     

Aspects of Scalar Brane-World Cosmological Perturbations

We summarize an approach to deal with scalar brane-world cosmological perturbations based on Mukohyama's master equation. We also give its relation to one based on perturbing the effective Einstein's equations on the brane (involving the Weyl fluid).     

Similitude généralisée et modélisation géométrique à complexité réduiteGeneral similitude solutions and low-complexity geometric models

We present low complexity models for the transport of passive scalars for environmental applications. The model uses partial observations assimilation. Similitude solutions are proposed in a non symmetric metric based on travel times. The approach does not require the solution of any PDE and is mesh free. Also, the solution can be computed in one point only without computing the whole solution. To cite this article: B. Mohammadi, J.-M. Brun, C. R. Mecanique 334 (2006).     

Thermodynamic equilibrium in dielectric fluids

Summary A rigorous deduction of the thermodynamic-equilibrium condition is provided for a homogeneous, uncharged and linear dielectric fluid contained in an electrostatic field. Contrary to the previous ones, this deduction does not postulate the existence of a mechanical stress tensor and of a body force density in the polarized fluid. Then, the equilibrium condition is employed to obtain the mass density distribution of the fluid and to present a correct proof of the well-known formula for the attractive force between the plates of a plane-parallel capacitor immersed in the fluid.