Shakedown analysis of circular plates using a yield criterion of the mean

Structural optimization based on the shakedown theory is a powerful and promising technique. However, due to the nonlinearities of physical materials and the number of variable loads in real structures, it is computationally complex and time-consuming. To simplify the occurring non-linear, non-convex optimization problems, the paper suggests reducing the number of yield conditions. The so-called a yield criterion of the mean (integral yield condition) is analysed and explained in detail, which allows taking into account one yield condition for the entire finite element instead of multiple point-wise conditions. This approach shows promising results in numerical application to the optimization of a circular plate, considering a possibility of employing the yield criteria of the mean or pointwise yield conditions in different areas of the plate in particular. The methods applied are based on the assumptions of perfect plasticity and small deformations.     

A novel fuzzy multi-criteria decision framework for sustainable supplier selection with incomplete information

Both academic and corporate interest in sustainable supply chains has increased in recent years. Supplier selection process is one of the key operational tasks for sustainable supply chain management. This paper examines the problem of identifying an effective model based on sustainability principles for supplier selection operations in supply chains. Due to its multi-criteria nature, the sustainable supplier evaluation process requires an appropriate multi-criteria analysis and solution approach. The approach should also consider that decision makers might face situations such as time pressure, lack of expertise in related issue, etc., during the evaluation process. The paper develops a novel approach based on fuzzy analytic network process within multi-person decision-making schema under incomplete preference relations. The method not only makes sufficient evaluations using the provided preference information, but also maintains the consistency level of the evaluations. Finally, the paper analyzes the sustainability of a number of suppliers in a real-life problem to demonstrate the validity of the proposed evaluation model.     

Slow and fast diffusion effects in image processing

A mathematical model for a nonlinear image multiscale analysis is studied. Processing of an image is based on a solution of the strongly nonlinear parabolic partial differential equation, which can degenerate depending on values of the greylevel intensity function. The governing PDE is a generalization of the regularized (in the sense of Catté, Lions, Morel and Coll) Perona-Malik anisotropic diffusion equation. We present numerical techniques for solving the suggested initial-boundary value problem and also existence and convergence results. Numerical experiments are discussed. Received: 6 May 1998 / Accepted: 27 July 2000     

Unexpected products of the allyldiethylamine hydroformylation homogeneously catalyzed by rhodium complexes

Attempts to carry out the hydroformylation of allyldiethylamine homogeneously catalyzed by rhodium complexes led to unexpected formation of N,N,N,N-tetraethyl-1,4-diaminobutane and 4-(diethylamino)-1-butanole as final products. The role of the catalyst on the product formation and the reaction mechanism are briefly discussed.     

Direct magnetic problem solved by quaternion analog of 3-D Cauchy-Riemann system

Contents By applying the quaternion variant of the Cauchy integral formula the general solution of the direct magnetic problem is derived. The applicability of the method presented here is shown by investigating and calculating the outer field of a analytically magnetized sphere.

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Die Lösung der direkten Aufgabe der Magnetik mit Hilfe des Quaternionen Analogons des 3-D Cauchy-Riemann Systems

Übersicht Die allgemeine Lösung der direkten Aufgabe der Magnetik wird mit Hilfe der Quaternionenvariante des Cauchy-Integrals abgeleitet. Die Anwendbarkeit der vorgestellten, Methode wird am Beispiel des berechneten äußeren magnetischen Feldes einer analytisch magnetisierten Kugel untersucht.

     

Conversion electron Mössbauer spectroscopy of the surface crystallization of the Fe75Co9B16 amorphous alloy

Using a new design of helium-methane gas-flow detector of conversion electrons for Mössbauer spectroscopy, non-uniform nucleation of the primary -Fe-Co phase on both contact and free surfaces of the Ar(+H₂) annealed amorphous Fe₇₅Co₉B₁₆ alloy was observed in its early crystallization stage. In this state the amount of crystalline phase on the contact ribbon side surpasses that on the free one by a factor of three, whereas no traces of volume crystallization were observed in the transmission spectra. By applying ion implantation to both ribbon surfaces, a slight reduction of the crystalline phase contribution was found. Magnetic domain structure observations were performed in order to evaluate the influence of surface crystallization on magnetic properties.     

On the probability theory on MV algebras

 The paper contains a review of some results concerning probability theory on MV algebras (laws of large numbers, central limit theorem, martingale convergence theorem). Also some algebraic and methodical aspects are discussed.     

Influence of Particle Size Distribution,Moisture Content,and Particle Shape on the Flow Properties of Bulk Solids

Abstract

There has been a great deal of research on characterising bulk solids. However, some of the characteristics, particularly the time‐dependent and random changes of properties, still remain insufficiently understood. The focus of this article is to study the influence of particle size, size distribution, moisture content, and particle shape on the unconfined yield strength of bulk solids. We present some interesting results about the influence of the particle size distribution on the unconfined yield strength of a bulk solid and a new method for determining the influence of particle shape on the unconfined yield strength of a bulk solid, which was made possible by the design and use of a novel attritor.