- TITLE:
SIMULATION MODEL OF VOLTAGE INVERTER AS REGULATOR OF VARIABLE CHARACTER LOADS
- AUTHOR(S):
B. Boichev
- ABSTRACT:
The large number of electronic generators placed in operation and their capabilities determine the cause many researchers to discuss intensively the issue of their use for control of reactive loads. Paper deals with investigation of the possibility of inverters application as regulators of loads with variable character using computer simulations.
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SIMULATION MODEL OF VOLTAGE INVERTER AS REGULATOR OF VARIABLE CHARACTER LOADS
- TITLE:
MICROWAVE ASSISTED SYNTHESIS OF 2-PIPERIDONE AND 2-PYRROLIDONE- MORPHINANES
- AUTHOR(S):
D. Vasilev
- ABSTRACT:
The conventional technique of heat is slower and leads to degradation once the products. The use of microwaves not only reduces the reaction time from hours to minutes, but increased the yield and selectivity. These are the reasons microwave organic synthes is can be applied in industry.The microwave heat is very efficient source of energy and can be used to greatly reduce the reaction time of a series of
organic reactions. In this work is studied referral codeinone in reactions of hetero-cyclization with 1,3-binucleophiles, with the participation of the α, β-unsaturated ketone system in its molecule.
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MICROWAVE ASSISTED SYNTHESIS OF 2-PIPERIDONE AND 2-PYRROLIDONE- MORPHINANES
- TITLE:
MONITORING OF E-LEARNING EFFICIENCY
- AUTHOR(S):
L. Skopalik
- ABSTRACT:
E-learning is a priority at European and national level and for TU-Gabrovo. Using attractive modules for e-learning with high quality is with a particular importance. The paper presents the developed approach and the chosen criteria for monitoring of efficiency of e-learning modules. Pilot evaluation of the efficiency of e-learning courses, applying developed methodology and criteria are presented. The results from the monitoring are used for improving e-learning quality.
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MONITORING OF E-LEARNING EFFICIENCY
- TITLE:
A NEW NONCONFORMING RECOVERY ALGORITHM FOR TWO-SIDED BOUNDS OF EIGENVALUES
- AUTHOR(S):
A. Andreev, M. Racheva
- ABSTRACT:
In recent papers the authors present and develop an original method for obtaining two-sided bounds of the exact eigenvalues. This idea is based on the combination of nonconforming finite element methods giving lower bounds of eigenvalues and a postprocessing procedure using conforming finite element spaces. Here a new approach is proposed, applicable to second- and fourth-order eigenvalue problems. Namely, a conforming finite element method is used for eigenpairs approximation and then by means of nonconforming recovery interpolant a lower bound approximation of the exact eigenvalues is obtained when the mesh parameter 0h > is sufficiently small. Some appropriate combinations of finite elements (conforming and nonconforming) which fulfil the algorithm are presented and discussed. Numerical experiments illustrating the efficiency of the proposed method are also given.
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A NEW NONCONFORMING RECOVERY ALGORITHM FOR TWO-SIDED BOUNDS OF EIGENVALUES
- TITLE:
EXPERIMENTAL STUDY OF THE FRICTION IN SLIDE BURNISHING
- AUTHOR(S):
A. P. Anchev, G. V. Duncheva, V. T. Kuzmanov
- ABSTRACT:
This article has been devoted of experimental study of the friction in the slide burnishing process when unhardened low-alloy steel is subjected to burnishing by means of synthetic diamond with spherical tip. An extended experimental design, based on an optimal composed second-order design with 24 experimental points, has been used. A regression analysis has been conducted and a model of the friction coefficient, depending on the burnishing parameters, has been obtained. The influence of the factors on the model has been studied through both analysis of variance (ANOVA) and sections of the hyper-surface of the model by hyper-planes.
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EXPERIMENTAL STUDY OF THE FRICTION IN SLIDE BURNISHING
