In this research, optimization process of axisymmetric extrusion dies is proposed. Plastic zone is analyzed using finite element method in the Eulerian system with flow formulation. The die profiles are defined by Bezier curves with six control points. Two effective functions are considered in this research; standard deviation of the strain rate and the rate of energy consumption during extrusi...

This paper proposes a new method for image compression. The method is based on the approximation of an image, regarded as a function, by a linear spline over an adapted triangulation, D(Y ), which is the Delaunay triangulation of a small set Y of significant pixels. The linear spline minimizes the distance to the image, measured by the mean square error, among all linear splines over D(Y ). The...

ZUSAMEN-FASSUNG:  Die oben angefuerte Erlaeuterung und Dis­kussion umfasst (I)- normale Entwicklung ein­zelner Hauptkomponente des menschlichen Immunmechanismus, ( 2) Faktoren, die moegli­cherweise fetalen Immunsystem aktivieren, (3) Faktoren, welche die Entwicklung des Immun­systems stoeren koennen.  REFERENCES 

ausser der traditionellen nutzung der geothermalen energie sind in jungster zeit neue erkenntnisse und projekte in ausarbeitung, die fur die zukunft ausserst wichtig sein konnen. bei einigen dieser projekte hat man bereits einige sehr positive ergebnisse erzielt. ausserdem wurde klar, das die ausgaben fur exploration,und expleitaion wirtscnaftlich ohneweiteres vsrtretbar sind,j•a sogar in hinbl...

Fullering process is a type of open die forging. In this research, elongation and maximum sideways spread in final shape of a billet after the first blow of a fullering process are predicted by designing a back propagation multilayer perceptron neural network. Several experiments are conducted using lead as the model material. Billets with three different square cross-sections are used in these...

Rectangular waveguide is one of the earliest types of transmission lines. Rectangular waveguide can be produced by hot extrusion process. In this paper, the hot extrusion process of CuZn5 rectangular waveguide was investigated by Finite Element Method (FEM). In addition, Genetic Algorithm (GA) was used to optimize the die geometry and process conditions to achieve the lowest magnitude of extrus...

In any metal forming process, both the strain rate and deformation rate depend on the die profile. The die profile also, is responsible for the non-uniformity of the deformation along the cross-section. These affect the quality and mechanical properties of the product. Therefore, if a die is designed, in which the affecting variables can be controlled spontaneously it is hoped to obtain a produ...

Mathematisch-naturwissenschaftlichen Fakultät Doctor of Philosophy Twisted Second Moments and Explicit Formulae of the Riemann Zeta-Function by Nicolas Martinez Robles Verschiedene Aspekte, die analytische Zahlentheorie und die Riemann zeta-Funktion verbinden, werden erweitert. Dies beinhaltet: 1. explizite Formeln, die eine Verbindung zwischen der Möbiusfunktion und den nichttrivialen Nullstel...

We introduce a square lattice into the Penna bit-string model for biological ageing and study the evolution of the spatial distribution of the population considering different strategies of childcare. Two of the strategies are related to the movements of a whole family on the lattice: in one case the mother cannot move if she has any child younger than a given age, and in the other case if she ...