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Found 5164 publications

Reversible DC-to-DC converter for a dual voltage automotive system using zero voltage switching technique

Dan V. Nicolae Petre Scortaru Zoltán Puklus Mihai Cernat

Publication Name: 11th International Conference on Optimization of Electrical and Electronic Equipment Optim 2008

Publication Date: 2008-01-01

Volume: Unknown

Issue: Unknown

Page Range: 251-258

Description:

A novel hysteretic controller for a bi-directional dc-dc converter with ZVS and interleaving for dual voltage systems in automobiles is presented. A variable frequency extended band hysteretic current control method is proposed. In comparison with classical fixed frequency current control PWM, the reverse polarity peak current needed for ZVS operation is kept constant Inductor current ripple decreases with load reduction. Automatic changes in operation between buck and boost modes are accomplished without transient currents. Converter simulations are carried out using Matlab/Simulink platform.

Open Access: Yes

DOI: 10.1109/OPTIM.2008.4602417

A long-distance runner in the colours of two clubs. Kálmán Kulcsár is eighty

Károly Varga

Publication Name: Tarsadalomkutatas

Publication Date: 2008-01-01

Volume: 26

Issue: 2

Page Range: 131-141

Description:

We greet a scholar, politician and researcher of major format on the occasion of his eightieth birthday. During his life full of work Kálmán Kulcsár has introduced new disciplines in Hungary, as a science politician he made major efforts for the establishment and consolidation of the institutions of sociology and political science. As a professor he taught the theory of the state and of law, and the sociology of law to generations, as a politician and Minister of Justice he did a great deal for the legal preparation of the change of the political system. As a diplomat he represented our country in Ottawa to the satisfaction of all. Above all he is an extremely prolific researcher who publishes his interesting writings to this day. His interest extends over theoretical questions to the development of individual societies, from Europe to Asia, his profundity is legendary; his clear-cut style makes his writings enjoyable to the reader. We hope that he would surprise his associates, disciples and the Hungarian academic life with several new works to come. © 2008, Akadémiaí Kiadó.

Open Access: Yes

DOI: 10.1556/Tarskut.26.2008.2.1

Health and health-related behaviour of future and graduated professional female nurses and doctors

Kovácsné Tóth Ágnes Helga Judit Feith Péter Balázs

Publication Name: Mentalhigiene Es Pszichoszomatika

Publication Date: 2008-01-01

Volume: 9

Issue: 4

Page Range: 289-304

Description:

Medical and nursing professions are stressing due to a number of major problems: high work related expectations, inadequate workplace conditions, the severe psychological burden placed on employees by the nature of their job. This study analyses the self-rated general and psychosocial health of female students and professional physicians and nurses related to healthy lifestyle habits and individual behavioural patterns. Method: our cross-section research was carried out among female nursing college students (N = 226), female medical students (N = 117), and among professional nurses and female doctors in hospitals (N = 409). Results: six out of ten staff members mentioned at least one health problem. To the self-rated health (SRH) of students and professional doctors and nursing staff were strongly related psychosomatic symptoms (p<0,001), pessimistic future expectations (p<0,001), perceived difficulties while maintaining the actual partnership (p = 0,001), and physical activity (p<0,001). About 40% (in student surveys 47,0%) said that they did some sports once a week or even more frequently. Smokers were represented with 16,7% (in student surveys 22,9%). Conclusion: results obtained suggest that health is not a highly appreciated value among female students and staff members in the Hungarian health care, moreover, their health-related behaviour is at a substandard level. Their roles as a social model in health promotion are rather questionable, for their insufficient health and risk behaviours. © 2008 Akadémiai Kiadó.

Open Access: Yes

DOI: 10.1556/Mental.9.2008.4.1

Design of active magnetic bearing

Tamás Ludvig Miklós Kuczmann

Publication Name: Journal of Optoelectronics and Advanced Materials

Publication Date: 2008-01-01

Volume: 10

Issue: 7

Page Range: 1834-1836

Description:

The paper deals with the analysis of an Active Magnetic Bearing system by the Finite Element Method and the magnetic vector potential formulation. This work proposes an optimal shape and dimensions of the legs of stator and air gap.

Open Access: Yes

DOI: DOI not available

Scalar hysteresis measurement using FFT

Miklós Kuczmann

Publication Name: Journal of Optoelectronics and Advanced Materials

Publication Date: 2008-01-01

Volume: 10

Issue: 7

Page Range: 1828-1833

Description:

The paper deals with a possible realization of eliminating the effect of noise in scalar hysteresis measurements. The measured signals have been transformed into the frequency domain, and after applying digital filter, the spectrums of the filtered signals have been transformed back to the time domain. The proposed technique results in an accurate noise removal algorithm. The paper illustrates a fast controlling algorithm applying the inverse of the actually measured hysteresis loop, and another proportional one to measure distorted flux pattern. Developing the mentioned algorithms aims the controlling of more complicated phenomena, i.e. measuring the vector hysteresis characteristics.

Open Access: Yes

DOI: DOI not available

Organizing the prevention of trachoma in Hungary (1884-1903)

Balázs Pálvölgyi

Publication Name: Orvostorteneti Kozlemenyek

Publication Date: 2008-01-01

Volume: 54

Issue: 1-4

Page Range: 47-68

Description:

In Hungary preventative measures against trachoma began in the winter of 1883-1884. Initially based on the recently issued public health law, it was imbedded in a general prevention programme against various epidemics. Local authorities and municipal boards were made responsible for carrying it out. These authorities and boards were obliged to organize supervision, to establish medical offices and ophthalmological wards and to take charge of the continuity of treatments. The public health department, however, faced serious difficulties, since most of the communities did not have the financial resources for such provision nor did they have enough trained physicians. Since the spread of trachoma could not be stopped by these measures, a new and effective solution had to be found. A new article was created for this purpose, the so called fifth article of the year 1886 "On preventing the spread of trachoma", which placed the burden of expenses for treatment - in case of lack of means - on the state budget. The government set up specialized professional training and the ophthalmological hospital system became specialized and modernised with the establishment of special trachoma hospitals, or--in public hospitals--ophthalmological wards. Although the first preventative measures were taken during the period mentioned above, the disease itself persisted, still occurring in large numbers of cases as late as the end of the Second World War.

Open Access: Yes

DOI: DOI not available

Challenges and responses in the geo-engineering education

Peter Scharle

Publication Name: Proceedings of the 1st International Conference on Education and Training in Geo Engineering Sciences Soil Mechanics Geotechnical Engineering Engineering Geology and Rock Mechanics

Publication Date: 2008-01-01

Volume: Unknown

Issue: Unknown

Page Range: 443-446

Description:

Structural engineers assess the geotechnical problems as difficult to model, complicated to calculate and full of crude approximations. In return, clear constraints hindering the practical use of advanced mechanical theories and computational software decrease the interest of geotechnicians in studying and applying them. In designing complex structures both sides restrict themselves in many cases to the exchange or prescription of some data given on interfaces. The paper presents an overviewon differences either loosing their importance or remaining significant between these structural and geotechnical perspectives. Educational consequences related to the Bologna-process are discussed. Role of case studies and understanding of the observational method's importance are stressed. The paper concludes that geotechnical education should and could correspond to the challenges with more conscious and better structured curricula. © 2008 Taylor & Francis Group, London.

Open Access: Yes

DOI: DOI not available

Managing the resolution of simulation models

No authors available

Publication Name: ESM 2008 - 2008 European Simulation and Modelling Conference: Modelling and Simulation 2008

Publication Date: 2008-01-01

Volume:

Issue:

Page Range: 38-42

Description:

A novel approach based on inflation and deflation is proposed for managing the resolution of simulation models. Different methods are proposed for manual or automatic deflation. An example is given how a topology description language can be extended to support the inflation/deflation concept. Dynamic management of the model resolution is introduced using the method called inflate-the-next and also two of its possible improvements. © 2008 EUROSIS-ETI.

Open Access: No

DOI: DOI not available

On the classification of 3D periodic polyhedral cellular systems

Enikö Bitay J. Tamás Reti

Publication Name: Materials Science Forum

Publication Date: 2008-01-01

Volume: 589

Issue: Unknown

Page Range: 341-348

Description:

In several fields of materials science space-filling polyhedral systems are generally used for modeling and characterizing the microstructure of polycrystalline and cellular materials. In this paper a simple quantitative method designated to classify 3D triply periodic, space-filling, cellular systems is outlined. The concept of the proposed method is based on the known analogy between the combinatorial structure of 3D space-filling polyhedral systems and of 4D polytopes. For classification purposes various topological shape indices are defined and tested. It is demonstrated that using two appropriately selected shape factors (asymmetry and compactness coefficients) a global combinatorial classification of cellular systems can be performed.

Open Access: Yes

DOI: 10.4028/www.scientific.net/msf.589.341