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Found 5152 publications

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

T. Reti

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

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

A simple technique to estimate the processing window for laser clad coatings

No authors available

Publication Name: International Surface Engineering Congress - Proceedings of the 1st Congress

Publication Date: 2003-12-01

Volume:

Issue:

Page Range: 237-242

Description:

A semi-empirical method for selecting the processing parameters of laser cladding is proposed. This phenomenological approach uses simple mathematical formulae, derived from a statistical analysis of measured data, to relate the laser cladding parameters with the geometric features of the clad track. Given the required clad height and available laser beam power, the proposed method allows one to calculate values of the scanning speed and powder feed rate which are used to obtain low dilution, pore free coatings, fusion bonded to the substrate. To illustrate the application of this method, variable powder feed rate laser cladding experiments were carried out with Stellite 6 powder on mild steel substrates. In this technique the laser beam power and radius and the processing speed are kept constant, while the powder feed rate is varied along a single track length according to a specified linear function. The expressions derived from the model were used to plot the experimental data in a coherent manner, revealing the combined role of the different processing parameters.

Open Access: No

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

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

Biomedical Engineering Education and Related Research Activity in Hungary

Balázs Benyó P. Somogyi L. Kovács L. Szilágyi Zoltán Benyó Péter Várady

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

Publication Date: 2003-12-01

Volume: 4

Issue: Unknown

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: Yes

DOI: DOI not available

Visualization and art in the mathematics classroom

Angela Schwenk Norbert Kalus Éva Veronika Rácz Gyor János Karsai Szeged

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: Yes

DOI: DOI not available

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

L. Costa A. M. Deus R. Colaço T. Reti R. Vilar

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

Publication Date: 2003-12-01

Volume: Unknown

Issue: Unknown

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: Yes

DOI: DOI not available

Enhanced emulated digital CNN-UM (CASTLE) arithmetic cores

P. Keresztes T. Hidvégi P. Szolgay

Publication Name: Journal of Circuits Systems and Computers

Publication Date: 2003-12-01

Volume: 12

Issue: 6

Page Range: 711-738

Description:

An emulated digital CNN-UM (CASTLE) architecture was published few years ago.1 Different emulated digital CNN-UM architectures are analyzed in the paper. These new modified architectures are optimized according to the silicon area, operating speed or dissipated power. A reconfigurable arithmetic core will also be shown in the paper, by which solution of the neighborhood size can be changed. An advanced CASTLE with pipe-lining is presented. The operation frequency is increased by using this solution in approximately 10 times.

Open Access: Yes

DOI: 10.1142/S0218126603001136