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205 results on '"Mladenov G"'

1. Application of methodology for the organization of a roundabout to increase the capacity of a conventional intersection of Sofia. Part II: Road traffic loading.

Author

Mladenov, G. D. and Stoyanov, S. P.

Subjects
*TRAFFIC circles, *TRAFFIC flow, *ENTRANCES & exits, *COMPARATIVE studies
Abstract

This article presents the results of experimental studies transport flows by source and destination. in this way, the aim is to prove a methodology developed and proposed to the Municipality of Sofia for the reconstruction of a roundabout in order to improve the traffic capacity. The results for the correspondences between the entrances and exits of the intersections before and after the reconstruction are obtained by simultaneous video capture of the traffic flows passing through the intersection within 1 peak hour. In this part, a comparative analysis of the traffic flow correspondences measured before and after the reconstruction of the three-way intersection into a roundabout was performed. The comparison of the results and their analysis will give an assessment of the expediency of the performed reconstruction and will also serve as a proof of the accuracy of the proposed methodology for the reconstruction of intersections in roundabouts. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Application of methodology for the organization of a roundabout to increase the capacity of a conventional intersection of Sofia. Part I: Geometric characteristics.

Author

Mladenov, G. D.

Subjects
*TRAFFIC circles, *INFRASTRUCTURE (Economics), *CITY traffic, *TRAFFIC safety, *TRAFFIC flow, *EVALUATION methodology
Abstract

This article presents an application of a developed methodology for the reorganization and evaluation of transport situations after the conversion of the movement of cars through a conventional three-way intersection into their movement through a roundabout. The only correct approach to improving the organization of road traffic is the correct choice of solutions for the organization and reorganization of traffic on the existing road. The research carried out is checking the improvement of the conditions, organization and safety of the traffic and whether the capacity of the intersection of a particular intersection has increased before and after its reconstruction from a three-way to a roundabout. What is specific about the developed methodology and the specific proposal for the reconstruction of an intersection is that it complies with the accepted limitations of the existing street areas and checks whether the movement of cars from all traffic flows in the busiest hours of the day in terms of traffic is unhindered. The necessary research and studies have been conducted to successfully identify and implement the most effective methods and approaches for the overall organization of road traffic and street design and reconstruction of the transport infrastructure. [ABSTRACT FROM AUTHOR]

Published
2024
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19. Numerical model of the plasma formation at electron beam welding.

Author

Trushnikov, D. N. and Mladenov, G. M.

Subjects
*ELECTRON density, *LIQUID metals, *ELECTRON energy states, *MASS transfer, *CHARGE exchange, *ELECTROSTATIC fields, *ELECTRIC fields
Abstract

The model of plasma formation in the keyhole in liquid metal as well as above the electron beam welding zone is described. The model is based on solution of two equations for the density of electrons and the mean electron energy. The mass transfer of heavy plasma particles (neutral atoms, excited atoms, and ions) is taken into account in the analysis by the diffusion equation for a multicomponent mixture. The electrostatic field is calculated using the Poisson equation. Thermionic electron emission is calculated for the keyhole wall. The ionization intensity of the vapors due to beam electrons and high-energy secondary and backscattered electrons is calibrated using the plasma parameters when there is no polarized collector electrode above the welding zone. The calculated data are in good agreement with experimental data. Results for the plasma parameters for excitation of a non-independent discharge are given. It is shown that there is a need to take into account the effect of a strong electric field near the keyhole walls on electron emission (the Schottky effect) in the calculation of the current for a non-independent discharge (hot cathode gas discharge). The calculated electron drift velocities are much bigger than the velocity at which current instabilities arise. This confirms the hypothesis for ion-acoustic instabilities, observed experimentally in previous research. [ABSTRACT FROM AUTHOR]

Published
2015
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35. Synthesis and characterization of fluorinated telomers containing vinylidene fluoride and hexafluoropropene from 1,6-diiodoperfluorohexane

Author

Ameduri, Bruno, Mladenov, G., Ameduri, B., Kostov, Georges, Mateva, R., Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Laboratoire des Systèmes d'Information Chimique (LSIC - ENSCM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS), Department of Plastics Technology, University of Sofia, and projet OTAN 2004-2006

Subjects
Polymers and Plastics, nuclear magnetic resonance (NMR), 02 engineering and technology, 010402 general chemistry, Elastomer, 6-diiodoperfluorohexane, radical cotelomerization, 01 natural sciences, chemistry.chemical_compound, Polymer chemistry, Materials Chemistry, Molecule, Thermal stability, Telechelic polymer, Chemistry, vinylidene fluoride, thermal properties, Organic Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Amorphous solid, [CHIM.POLY]Chemical Sciences/Polymers, telechelics, Proton NMR, Suspension polymerization, 0210 nano-technology, Fluoride
Abstract

The synthesis of original fluorinated (co)telomers containing vinylidene fluoride (VDF) or VDF and hexafluoropropene (HFP) was achieved by radical telomerizations and (co)telomerizations of VDF (or VDF and HFP) in the presence of 1, 6-diiodoperfluorohexane via a semisuspension process. tert-Butyl peroxypivalate (TBPPi) was used as an efficient thermal initiator. The numbers of VDF and VDF/HFP base units in the (co)telomers were determined by 19 F and 1 H NMR spectroscopy. They ranged from 10 to 190 VDF base units. Fluorinated telomers of various molecular weights (1200-12,600 g/mol) were obtained by the alteration of the initial [1,6-diiodoperfluorohexane] 0 /[fluoroalkenes] 0 and [TBPPi] 0 /[fluoroalkenes] 0 molar ratios. The thermal properties of these fluorinated (co)telomers, such as the glass-transition temperature and melting temperature, were examined. As expected, these telomers exhibited good thermal stability. They were stable at least up to 350 °C. The compounds containing more than 30 VDF units were crystalline, whereas all those containing VDF-co-HFP were amorphous with elastomeric properties, whatever the number was of the fluorinated base units. The structures of I-(VDF) n -R F -(VDF) m -I and I-(HFP) x (VDF) n -R F -(VDF) m (HFP) y -I (co)telomers were obtained, and the defects of the VDF chain and the -CH 2 CF 2 I and -CF 2 CH 2 I functionalities were studied successfully (where R F = C 6 F 12 ). The functionality in the iodine atoms was modified: the higher the VDF content in the telomers, the lower the normal end functionality (-CH 2 CF 2 I) and the higher the reversed extremity (-CF 2 CH 2 I). In addition, the percentage of defects increased when the number of VDF units increased. The molecular weights and molecular weight distributions of different telomers and cotelomers were also studied.

Published
2006

36. Ion beam impact and penetration of polymethyl methacrylate.

Author

Mladenov, G. M., Braun, M., Emmoth, B., and Biersack, J. P.

Subjects
*ENERGY dissipation, *ION implantation, *POLYMETHYLMETHACRYLATE
Abstract

Presents a study that calculated the depth distribution of energy dissipation and ion implantation ranges in the polymer resist polymethyl methacrylate (PMMA). Methodology; Correlation between the electronic and nuclear energy losses and penetration depth; Examination of the emission yield of PMMA during the initial stage of ion bombardment and electronic energy loss.

Published
1985
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