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Found 6515 publications

Residual stresses in carburised, carbonitrided and case-hardened components (Part 2)

Tamás Réti

Publication Name: Heat Treatment of Metals

Publication Date: 2004-03-11

Volume: 31

Issue: 1

Page Range: 4-10

Description:

An overview is given of the significant progress in research focused on the assessment of residual stress effects in case-hardened components. Focus is on relevant computational models intended to simulate stress evolution during heat treatment.

Open Access: Yes

DOI: DOI not available

Explicitation; A universal of translated text?

Vilma Papai

Publication Name: Benjamins Translation Library

Publication Date: 2004-01-01

Volume: 48

Issue: Unknown

Page Range: 143-164

Description:

This article reports on corpus-based investigation of explicitation generally referred to as one of the universal features of translation. It gives an account of the findings of a twofold analysis carried out on an English-Hungarian parallel corpus and a comparative corpus of translated and non-translated texts in Hungarian. The purpose is to reveal the regularities of both the translation process in terms of explicitation and the translation product in terms of text explicitness. The paper will argue that there is a close connection between explicitation and simplification, another candidate for translation universals.

Open Access: Yes

DOI: 10.1075/btl.48.12pap

Taylor series method with numerical derivatives for initial value problems

Gyozo Molnárka E. M. Miletics

Publication Name: Journal of Computational Methods in Sciences and Engineering

Publication Date: 2004-01-01

Volume: 4

Issue: 1-2

Page Range: 105-114

Description:

The Taylor series method is one of the earliest analytic-numeric algorithms for approximate solution of initial value problems for ordinary differential equations. The main idea of the rehabilitation of these algorithms is based on the approximate calculation of higher derivatives using well-known technique for the partial differential equations. In some cases such algorithms will be much more complicated than a R-K methods, because it will require more function evaluation than well-known classical algorithms. However these evaluations can be accomplished fully parallel and the coefficients of truncated Taylor series can be calculated with matrix-vector operations. For large systems these operations suit for the parallel computers. The approximate solution is given as a piecewise polynomial function defined on the subintervals of the whole interval and the local error of this solution at the interior points of the subinterval is less than that one at the end point. This property offers different facility for adaptive error control. This paper describes several above-mentioned algorithms and examines its consistency and stability properties. It demonstrates some numerical test results for stiff systems herewith we attempt to prove the efficiency of these new-old algorithms.

Open Access: Yes

DOI: 10.3233/jcm-2004-41-213

A meshless polyharmonic-type boundary interpolation method for solving boundary integral equations

Csaba Gáspár

Publication Name: Engineering Analysis with Boundary Elements

Publication Date: 2004-01-01

Volume: 28

Issue: 10 SPEC. ISS.

Page Range: 1207-1216

Description:

A boundary interpolation technique is introduced based on multi-elliptic partial differential equations. The interpolation problem is converted to a special higher order partial differential equation which is completely independent of the geometry of the original problem. Based on this interpolation method, meshless methods are constructed for the 2D Laplace-Poisson equation. The presented approach makes it possible to avoid solving large and dense interpolation equations. The auxiliary higher order partial differential equation is solved by robust, quadtree-based multi-level methods. The results can be easily generalized to 3D problems as well. © 2004 Elsevier Ltd. All rights reserved.

Open Access: Yes

DOI: 10.1016/j.enganabound.2003.04.001

Residual Stresses in Carburised, Carbonitrided and Case-hardened Components (Part 1)

Tamás Réti

Publication Name: Heat Treatment of Metals

Publication Date: 2003-12-08

Volume: 30

Issue: 4

Page Range: 83-96

Description:

The assesment of residual stress effects in carburised, carbonitride and case-hardened components was discussed. The development of computational models and procedures, which were applied to the simulation of the stress-evolution processes during heat treatment was also discussed. Shot peening, the most versatile method of producing residual stresses was studied. The influence of microstructure and residual stresses on crack initiation and propagation was discussed.

Open Access: Yes

DOI: DOI not available

Biomedical Engineering Education and Related Research Activity in Hungary

No authors available

Publication Name: Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings

Publication Date: 2003-12-01

Volume: 4

Issue:

Page Range: 3533-3535

Description:

Biomedical Engineering is a relatively new interdisciplinary science. This paper presents the biomedical engineering activity, which is carried out at Budapest University of Technology and Economics and its partner institutes. In the first part the main goals and the curriculum of the Biomedical Engineering ducation Program (BMEEP) is presented. The second part of the paper summarizes the most important biomedical engineering researches carried out mostly in the Biomedical Engineering Laboratory of our university.

Open Access: No

DOI: DOI not available

Validity of a 2-km Walk Test in predicting the maximal oxygen uptake in moderately active Hungarian men

Géza Zakariás R. Laukkanen M. Petrekanits

Publication Name: European Journal of Sport Science

Publication Date: 2003-12-01

Volume: 3

Issue: 1

Page Range: 1-8

Description:

The present study examined whether prediction models based on the 2-km UKK Walk Test (UWT) are valid for predicting the maximal oxygen uptake or maximal aerobic power (VO2max) in moderately active Hungarian men. Eightyseven 24-62 year old, non-athletic, sedentary or moderately physically active men were studied. Maximal aerobic power was measured in a maximal uphill walk exercise test on a treadmill. The walking tests were performed on a 400-m outdoors athletic track. The subjects walked 2 km (5 laps) as briskly as they could. VO2max was predicted with the formula as established in the original development study of the UWT. The total error of prediction and the correlation coefficient between the laboratory measured and UWT predicted VO2max (ml · kg-1 · min-1) were 4.6 and 0.85. The Bland-Altman analysis showed a good agreement between the methods, with the mean error of prediction 0.05 ml · kg-1 · min-1. The results verify that the UWT can be used as a reasonably valid test for predicting maximal aerobic power in Hungarian men. © 2002 by Human Kinetics Publishers and the European College of Sport Science.

Open Access: Yes

DOI: 10.1080/17461390300073104

Visualization and art in the mathematics classroom

No authors available

Publication Name: ZDM - International Journal on Mathematics Education

Publication Date: 2003-12-01

Volume: 35

Issue: 1

Page Range: 24-29

Description:

In this paper we summarize our concepts and practice on computer-aided mathematical experimentation, and illustrate them by Mathematica projects that we have developed for our research and the courses "Computer-aided mathematical modelling" and "Computer Algebra I-II" held for students of life sciences at University of Szeged and computational engineering at TFH Berlin, University of Applied Sciences.

Open Access: No

DOI: DOI not available

Tempering effects in steel parts produced by additive fabrication using laser powder deposition

No authors available

Publication Name: Virtual Modelling and Rapid Manufacturing - Advanced Research in Virtual and Rapid Prototyping

Publication Date: 2003-12-01

Volume:

Issue:

Page Range: Unknown

Description:

Laser processed tool steels present a metastable structure generally containing martensite and an extremely large proportion of retained austenite as compared to conventionally treated steel, which affects considerably the properties of the material. In rapid tooling by laser powder deposition, as consecutive layers of material are deposited to generate a 3D object, the material in previously deposited layers is submitted to successive thermal cycles, which destabilise retained austenite, leading to its transformation to martensite. Also, the martensite present in these layers will progressively decompose by tempering when the material is reheated. As a result, the properties of the material are progressively modified as the object is built-up. The evolution of the microstructure and properties of tool steels during laser freeform manufacturing is extremely difficult to study experimentally, due to the complexity of the transformations involved and the heterogeneity of the material and of the applied thermal field, hence modelling presents clear advantages in the optimization of part build-up strategy. In the present work, a model of the phase transformations resulting from the successive overlap of clad layers based on the coupling of finite element calculations of the time-dependent temperature distribution with transformation kinetics is described. The model was used to predict the evolution of properties and final property distribution in a martensitic stainless steel component produced by laser powder deposition.

Open Access: No

DOI: DOI not available