Elena Koleva

20190910-02
Overall robust optimization approach for electron beam induced grafting process
Lilyana Koleva, Elena Koleva, Monica R. Nemtanu, Mirela BraƟoveanu

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The article presents a review of how to pick or design the correct most cost-effective BLDC (Brushless Direct Current) motor controller to fit the needs of the project. After a brief overview of the history and presenting ...  read more

20190708-04
Academic writing and integration of technology
Maria Todorova, Elena Koleva

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Communication in a foreign language is already becoming a daily routine for many, personally, professionally and academically. Professional realization requires skills for writing documents such as biographies, cover letters, ...  read more

20190506-04
Welding in space and in vacuum chambers
Georgi M. Mladenov, Elena G. Koleva, Dmitriy N. Trushnikov

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This paper presents literature analysis of available sources on the Internet and the experience of the authors, describing the characteristic technologies of vacuum welding on earth and in space in the presence of weightlessness ...  read more

20190304-06
Simulation of the temperature distribution and modelling of molten pool parameters at electron beam drip melting of copper
Tsvetomira Tsonevska, Elena Koleva, Lilyana Koleva, Georgi Mladenov

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In this article quasi steady-state two-dimensional heat model is implemented for the simulation of the temperature distribution in the cast copper ingots through electron beam drip melting. Regression models are estimated ...  read more

20180910-05
Model-based approach for the shape estimation of electron beam welding joints
Tsvetomira S. Tsonevska, Elena G. Koleva, Georgi M. Mladenov

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This article discusses a modeling approach for the obtained by electron beam welding molten pool shapes, which is based on experimental data, type mathematical function and regression analysis. The process of electron beam ...  read more

20180910-07
Model-driven development of event management system
Tsvetelina Ivanova, Elena Koleva, Idilia Batchkova, Dobrin Nikolov

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Electron Beam Technologies Conference is an international conference, which originated in 1985. The challenge for the management of this event, as well as the numerous such events that are organized every year around the world, ...  read more

20180910-08
Analysis of the ergonomic quality of e-learning through statistical methods
Maria Todorova, Elena Koleva, Ivelina Kotseva

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A key factor in e-learning in the future will be a quality orientation that firstly places learners or users of education services. They have to take the lead in terms of quality concepts of e-learning, since their professional ...  read more

20140304-07
Neural network based approach for quality improvement of electron beam welding
Elena Koleva, Nikolinka Christova, Georgi Mladenov, Dmitrii Trushnikov, Vladimir Belenkiy

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Neural network models for the dependence of the geometry characteristics of welds from 38Cr2Ni2Mo high-strength steel, obtained at electron beam welding in presence of longitudinal beam deflection oscillations, are estimated. ...  read more

20140506-61
Analysis and Generalization of Scientific and Educational Information Book in the Field of Nano-Electronics
Victor M. Spivak, Elena G. Koleva, Anna G. Vlasyuk

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In this paper analysis and generalization of the scientific and educational properties of information textbooks on nano-electronics, created from the scientists of the Institute of Electronics at Bulgarian Academy of Sciences, ...  read more

20140506-46
Study of Electron Beam Resists: Negative Tone HSQ and Positive Tone SML300
Ivan Kostic, Anna Bencurova, Anna Konecnikova, Pavol Nemec, Adrian Ritomsky, Elena Koleva, Katia Vutova, Georgi Mladenov

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In this paper the contrast and sensitivity characteristics are investigated concerning the negative tone electron beam resist HSQ (hydrogen silsesquioxane) and the positive tone SML300 electron beam organic resist, designed ...  read more