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Found 5157 publications

Long-term effects of the ap-citrox decontamination procedure on the protective oxide-layer formed on stainless steel

Dezso Oravetz Gábor Patek Bernadett Baja Péter Kádár Andrea Nagyné Szabó Kálmán Varga Dezso Varga József Tóth Zoltán Németh István Cserny László Kövér János Schunk Zoltán Homonnay Erno Kuzmann

Publication Name: Korrozios Figyelo

Publication Date: 2007-07-09

Volume: 47

Issue: 3

Page Range: 62-72

Description:

Our previous studies have revealed that a "hybrid" structure of the amorphous and crystalline phases is formed in the outermost surface region of the austenitic stainless steel tubes of steam generators (SGs) as an undesired consequence of the industrial application of the AP-CITROX decontamination technology. The formation of this mobile oxide-layer increased the amount of the corrosion products in the primary circuit significantly (∼80 kg/block), resulting in magnetite deposition on fuel assemblies. As deposits blocked the cooling channels, the flow rate of water coolant through the reactor core decreased. Consequently, the power capacity of three nuclear reactor units had to be reduced, and full core fuel replacement became necessary. In the light of the above events, the present work gives a brief overview on the general corrosion state of the heat exchanger tubes of SGs, concerning the long-term effects of the AP-CITROX procedure on the chemical composition and structure of the protective oxide-layer. Owing to the fact that there is no investigation method available for the in-situ monitoring of the inner surfaces of heat exchanger tubes, a research project based on sampling as well as on ex-situ electrochemical and surface analytical measurements was elaborated. Within the frame of this project, comprehensive investigation of the general corrosion state and metallographic features of 36 stainless steel specimens, cut out from various locations of the four steam generators of the Paks NPP has been performed. Electrochemical (voltammetric) and surface analytical (SEM-EDX, CEMS, and XRD) results reveal that some beneficial changes in the corrosion properties, morphology and chemical composition of the inner surfaces of heat exchanger tubes can be observed in the time period of 2000-2006.

Open Access: Yes

DOI: DOI not available

Female physicians' and nurses' self-rated general and psychosocial health status and health behaviour in Hungary

Kovácsné Tóth Ágnes Feith Helga Judit Balázs Péter

Publication Name: New Medicine

Publication Date: 2007-07-01

Volume: 11

Issue: 3

Page Range: 55-58

Description:

Aim. This study analyses the self-rated general and psychosocial health of female physicians and nurses in Hungary related to healthy lifestyle habits and individual behavioural patterns. Material and method. cross-sectional data were taken by a questionnaire survey among Hungarian female health care staff members (N=409) selected representatively in 2005 (responding rate 45.5%). Results. Six out of ten staff members mentioned at least one health problem. Strongly related to self-rated health (SRH) were role conflicts (p<0.001), pessimistic future expectations (p<0.001), perceived difficulties in maintaining the actual partnership (p=0.001), and satisfaction with one's life and career (p<0.001). About 40% said that they did some sports once a week or even more frequently. Smokers represented 24.4%. Conclusion. The results obtained suggest that health is not a highly appreciated value among female staff members in Hungarian health care. Moreover, their health-related behaviour is at a substandard level. Improving this situation should be a priority aim of any intervention. ©Borgis.

Open Access: Yes

DOI: DOI not available

Product design using a contact-optimization technique

Attila Baksa Tamás Szabó István Páczelt

Publication Name: Strojniski Vestnik Journal of Mechanical Engineering

Publication Date: 2007-07-01

Volume: 53

Issue: 7-8

Page Range: 442-461

Description:

It is well known that in engineering practice high stresses occur and that these stresses depend on the shapes and the loads of the bodies in unilateral contact. The stress distribution is often not smooth and has some singularities, thereby decreasing the lifetime of the machine elements. It is an important objective to obtain a smooth stress distribution when optimizing the shape of the elements. One of the goals of this paper is to present a method that resolves the above problem. By controlling the contact pressure a prescribed, smooth contact-pressure distribution can be achieved. The optimization problems take into account the limit stress constraints of the material. In the present paper two types of contact problems are investigated. Firstly, contact optimization problems are analyzed assuming linear elasticity and small displacements, including steady-state wear process. Two numerical examples are presented on this topic for a rolling machine element: a punch optimization and a shape optimization. We also investigated which parameter values of the controlling function result in the maximum loadability. This can be useful in the design of brakes or bearings. In the second part of the paper the solution of the contact problem for large displacements and deformations is investigated where an air-spring is analyzed by calculating the nonlinear load-displacement curve and comparing it with measurements. © 2007 Journal of Mechanical Engineering. All rights reserved.

Open Access: Yes

DOI: DOI not available

Product design using a contact-optimization technique

No authors available

Publication Name: Strojniski Vestnik/Journal of Mechanical Engineering

Publication Date: 2007-07-01

Volume: 53

Issue: 7-8

Page Range: 442-461

Description:

It is well known that in engineering practice high stresses occur and that these stresses depend on the shapes and the loads of the bodies in unilateral contact. The stress distribution is often not smooth and has some singularities, thereby decreasing the lifetime of the machine elements. It is an important objective to obtain a smooth stress distribution when optimizing the shape of the elements. One of the goals of this paper is to present a method that resolves the above problem. By controlling the contact pressure a prescribed, smooth contact-pressure distribution can be achieved. The optimization problems take into account the limit stress constraints of the material. In the present paper two types of contact problems are investigated. Firstly, contact optimization problems are analyzed assuming linear elasticity and small displacements, including steady-state wear process. Two numerical examples are presented on this topic for a rolling machine element: a punch optimization and a shape optimization. We also investigated which parameter values of the controlling function result in the maximum loadability. This can be useful in the design of brakes or bearings. In the second part of the paper the solution of the contact problem for large displacements and deformations is investigated where an air-spring is analyzed by calculating the nonlinear load-displacement curve and comparing it with measurements. © 2007 Journal of Mechanical Engineering. All rights reserved.

Open Access: No

DOI: DOI not available

Thoughts on the necessity of security council reform

Gábor Sulyok

Publication Name: Acta Juridica Hungarica

Publication Date: 2007-06-01

Volume: 48

Issue: 2

Page Range: 143-167

Description:

The declared objective of recent efforts to reform the Security Council is to increase effectiveness. A careful investigation applying certain theses of organization theory, however, reveals that neither the prevailing structure nor the working methods of the Council unavoidably hamper the achievement of organizational goals; therefore, arguments pertaining to the issue of effectiveness do not necessarily justify reform proposals. A similar conclusion can be reached by examining other possible causes of reform, namely the fundamental change of organizational environment, power struggles between various principal organs of the United Nations, and some harshly criticized features of the Council itself. It seems that the necessity of reform is rooted in various individual and highly subjective interests of member states rather than objective circumstances, and the organization has no other option, but to fulfill their demands in order to secure its own survival. © 2007 Akadémiai Kiadó.

Open Access: Yes

DOI: 10.1556/AJur.47.2007.2.4

Monitoring of embankment construction processes

Edina Koch

Publication Name: Pollack Periodica

Publication Date: 2007-04-01

Volume: 2

Issue: 1

Page Range: 89-100

Description:

Nowadays more and more engineering structures are constructed on soft soils of low strength. High compressibility, low permeability and liability to secondary compression of these soils can result in long-term settlements and a menace with critical situations when the construction deadlines are tough. To cope with these problems several technologies have recently been developed in the embankment construction practice. Staged construction, over-filling, vertical drainage, stone columns, dynamic compaction - all of them often combined successfully with geosynthetics - are preferred to the previously predominant technology of soil replacement. Nevertheless, common design methods often do not balance properly the structural modeling, computation, economical and construction aspects. This is why a correct design may become a subject of reconsideration and modification in specific circumstances. There remains a room for innovative approaches, when conventional solutions are used. Two examples seem to prove that construction combined with monitoring may tum out to be good compromises. © 2007 Akadémiai Kiadó.

Open Access: Yes

DOI: 10.1556/Pollack.2.2007.1.8

Numerical analysis of a 2D vector hysteresis measurement system

Miklós Kuczmann

Publication Name: Pollack Periodica

Publication Date: 2007-04-01

Volume: 2

Issue: 1

Page Range: 17-26

Description:

This paper deals with the numerical analysis of a vector hysteresis measurement system, which is under construction in the laboratory. The aim is to build up a single sheet tester with round shaped specimen. The goal of simulations is to find out the main features of the measurement system. The 3D finite element method (FEM) with tetrahedral mesh developed in the laboratory has been applied for investigations of the nonlinear eddy current field problem. The characteristic of the magnetic material has been taken into account by the isotropic vector Preisach model. The nonlinearity has been handled by the polarization method and the nonlinear system of equations has been solved by the fixed-point technique. The first results are presented in this work. © 2007 Akadémiai Kiadó.

Open Access: Yes

DOI: 10.1556/Pollack.2.2007.1.2

Genetic and Bacterial Programming for B-Spline Neural Networks Design

J. Botzheim C. Cabrita A. E. Ruano L. T. Koczy

Publication Name: Journal of Advanced Computational Intelligence and Intelligent Informatics

Publication Date: 2007-03-01

Volume: 11

Issue: 2

Page Range: 220-231

Description:

The design phase of B-spline neural networks is a highly computationally complex task. Existent heuristics have been found to be highly dependent on the initial conditions employed. Increasing interest in biologically inspired learning algorithms for control techniques such as Artificial Neural Networks and Fuzzy Systems is in progress. In this paper, the Bacterial Programming approach is presented, which is based on the replication of the microbial evolution phenomenon. This technique produces an efficient topology search, obtaining additionally more consistent solutions.

Open Access: Yes

DOI: 10.20965/jaciii.2007.p0220

Law pertaining to political parties and political pluralism - Freedom of the foundation and functioning of political parties in post-communist Hungary

Peter Smuk

Publication Name: Acta Juridica Hungarica

Publication Date: 2007-03-01

Volume: 48

Issue: 1

Page Range: 71-85

Description:

This paper studies the law pertaining to political parties in Hungary, from the viewpoint of establishing and maintaining of political pluralism. In the period of 1989-1990, the transition from the one-party system to the democratic and pluralistic state of law could be followed up relative to the development of the law pertaining to the political parties, which is based on the rules that foreclose the contingent development of unconstitutional political system. The paper reviews the concept of the political party according to the constitutional law, the normative framework of functioning and the regulations of the internal organization of political parties. The provisions of primary importance concern: a) equality of political parties, b) forbidden purposes and instruments, c) rules of incompatibility, d) state subvention. Rules concerning the internal organization require the openness and the prevailing of democratic will-making also inside the political parties, so contribute to the maintaining the democratic competition of political parties. The author emphasizes the factors that determine multiparty-system, and argues that electoral thresholds and the effective method of state-financing of political parties contest the principle of equality and harm the fair-competition. Thresholds and subvention are both based on the effectiveness of political parties-though being capable to prevent the party system and the parliament from fragmentation, nonetheless, they prefer extensively, if not unconstitutionally, the political parties in the Parliament, so they can be seen as being designed to protect the current political elite. © 2007 Akadémiai Kiadó.

Open Access: Yes

DOI: 10.1556/AJur.47.2007.1.5