Elena G. Koleva

20230300-01
Evaluation of the integration of systems for quality management in the field of higher education
Pavlina Shopova, Maria Todorova, Lilyana S. Koleva, Elena G. Koleva

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For the purposes of continuous improvement of the quality management system in any organization, and in particular those in the field of higher education, an assessment of the degree of integration (maturity) of the system ...  read more

20230200-04
Robust model-based approach for electron beam lithography process control
Asya Asenova-Robinzonova, Elena G. Koleva

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The present study is directed toward the investigates the dependency of the geometric characteristics of the developed post-exposure negative electron resist AR-N 7520 profiles on the parameters of the electron beam lithography ...  read more

20230100-04
Manufacturing operations management system for the electron beam welding: process modelling using IEC/EN 62264 standard
Plamen V. Vasilev, Elena G. Koleva

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In the presented work the IEC/EN 62264 standard is implemented for the Manufacturing Operations Management (MOM) system modelling of the electron beam welding process. The basic information system structural elements for enterprise ...  read more

20220508-03
Optimization of electron beam welding of Ti-6Al-4V thin plates
Lilyana S. Koleva, Asya Lozeva, Elena G. Koleva

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In this paper the electron beam welding of Ti–6Al–4V thin plates is simulated by implementation of a moving linear heat source model. The simulation results are used for estimation of regression models for the dependencies ...  read more

20220508-04
Simulation of electron beam welding of Inconel 718 thin plates
Lilyana S. Koleva, Natalia Hristova, Elena G. Koleva

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In this paper the simulation of electron beam welding of Inconel 718 thin plates by a moving linear heat source is considered. Regression models for the molten pool geometry characteristics, depending on the electron beam ...  read more

20220508-05
Robust model-based multicriterial optimization strategies for electron beam welding of Steel 45
Elena G. Koleva, Lilyana S. Koleva

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In this paper an experimental study of the geometrical characteristics of the cross-sections of the thermally affected areas obtained by electron beam welding joints of carbon steel grade 45 is made. The thermally affected ...  read more

20210912-02
Process parameter optimization of electron beam melting and refining of titanium
Elena G. Koleva, Lilyana S. Koleva, Volodia V. Dzharov, Boriana S. Spasova

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The mechanical properties bending strength and modulus of elasticity in bending of a new type plywood for construction, based on black locust wood, have been investigated in relationship with the bonding technological factors. ...  read more