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of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

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Author: Veselin Petkov

  • TECHNOLOGIES

    Fabrication and mechanical testing of compacted and extruded specimens made of aluminium alloys chips

    • Angel Velikov
    • Tatiana Simeonova
    • Rumen Krastev
    • Tsvetan Tochev
    • Veselin Petkov
    Machines. Technologies. Materials., Vol. 16 (2022), Issue 11, pg(s) 379-382
    • Abstract
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    Four types of aluminium alloys (two casting and two plastically deformable) were used in the present study. A special press mould for compacting the aluminium alloy chips and subsequent extrusion of the resulting compacts was designed and manufactured. The compressive strength of the obtained samples was investigated, in relation to their chemical composition and technological parameters during their fabrication. The results of the research are presented in tabular and graphic form. It was established that compacted samples from AW-6082, AC-48000 and AW-2024 alloy possess high compression strength (in the range of 766 – 866 MPa) under compression loading at 60% deformation. It seems that the extrusion process improves compression properties of AW-2024 and AC-48000 alloy but has negative effect on AW-6082 and AC-42000.

  • INNOVATIVE SOLUTIONS

    Preparation of Ba0.95 Sm0.05 TiO3 Ceramics by Low Temperature Sol-Gel Method. Change in Dielectric Permittivity with Temperature

    • Mihaela Aleksandova
    • Lyuben Lakov
    • Vladimir Blaskov
    • Veselin Petkov
    • Yordan Marinov
    • Bojidar Jivov
    Innovations, Vol. 9 (2021), Issue 3, pg(s) 118-121
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    Barium titanate ceramics doped with samarium were synthesized by low temperature sol-gel method. The physicochemical characterization of the samples was carried out by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). A pure BaTiO3 cubic phase was obtained. A technological regulation has been developed for the preparation of test samples .Monitoring ofthe relative dielectric permittivity of Sm-doped BaTiO3 ceramics with temperature changes (at frequency of 10 kHz) was realized.The resulting curve is typical of ferromagnetic material. The synthesized barium titanate ceramics possesses a high dielectric constant – 17500 at a Curie temperature Tc (65oC). The obtained values for the relative dielectric permittivity and Curie temperature of Sm-doped barium titanate ceramics are much better in comparison to conventionally non-doped BaTiO3-εr = 2000 and Tc = 120°C.

  • MATERIALS

    Technological regulation for creating a ceramic target from BaTiO3 gel powders doped with Sn. Temperature dependence of the dielectric permittivity

    • Lyuben Lakov
    • Mihaela Aleksandrova
    • Vladimir Blaskov
    • Yordan Marinov
    • Veselin Petkov
    Machines. Technologies. Materials., Vol. 15 (2021), Issue 4, pg(s) 155-157
    • Abstract
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    The research is aimed at creating a target from Sn doped barium-titanate ceramics. A technological regulation for the preparation of test bodies from a material synthesized by a low-temperature sol-gel method has been developed. The physicochemical parameters of the samples were determined and the temperature dependence of the dielectric permittivity was monitored. Physicochemical characterization of the samples was performed by X-Ray diffraction (XRD). and scanning electron microscopy (SEM). The preparation of pure BaTiO3 cubic phase was established. The dielectric permittivity of Sn doped barium-titanate possesses a maximum value of 45000 at a Curie temperature- Tc 40oC.

  • MATERIALS

    Structure and composition of innovative porous composite material

    • Veselin Petkov
    • Rositza Dimitrova
    • Luben Lakov
    Machines. Technologies. Materials., Vol. 14 (2020), Issue 8, pg(s) 362-365
    • Abstract
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    The subject of this article is a study on the composition and structure of innovative Porous Composite Material (PCM). The latter is obtained from powders of glass waste and heat-treated rice husks. The PCM is non-flammable, non-combustible and has high heat and sound insulation properties. The structural elements made of it are lighter and stronger than the ones made of foam glass. It is expected that PCM is to find wide application in construction and as an absorbent of heavy metals and oil from polluted water

  • MATERIALS

    CERAMIC SUPERCAPACITOR

    • Luben Lakov
    • Petyo Ivanov
    • Mihaela Alexandrova
    • Veselin Petkov
    Machines. Technologies. Materials., Vol. 13 (2019), Issue 12, pg(s) 564-565
    • Abstract
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    This report examines the characteristics of powerful supercapacitors, which are used in electric vehicles to perform their driving dynamics, as well as to power starter motors of powerful internal combustion engines in large trucks, military vehicles and more. Main requirement for supercapacitors is tobe able to deliver a large amount of electricity for about ten seconds, and for very powerful motors (over 100 kW) – for up to 15 seconds. Various technological methods have been reported for supercapacitorsproduction, including the onedeveloped by the current authors, which is based on a ceramic dielectric with a high relative dielectric constant.

Congresses and conferences

  • IX International Scientific Conference
    "High Technologies. Business. Society"
    04.-07.03.2024 - Borovets, Bulgaria
  • XXI International Congress
    "Machinеs. Technolоgies. Materials."
    Winter session
    06.-09.03.2024 - Borovets, Bulgaria
  • XIX International Scientific Technical Conference
    "Foundry"
    17.-19.04.2024 - Pleven, Bulgaria
  • XXXI International Scientific Conference
    "trans&MOTAUTO"
    24.-27.06.2024 - Varna, Bulgaria
  • IX International Scientific Congress
    "Innovations"
    24.-27.06.2024 - Varna, Bulgaria
  • IX International Scientific Conference
    "Industry 4.0"
    Summer session
    26.-29.06.2024 - Varna, Bulgaria
  • XII International Scientific Congress
    "Agricultural Machinery"
    26.-29.06.2024 - Varna, Bulgaria
  • XI International Scientific Conference
    "Engineering. Technologies. Education. Safety"
    02.-05.09.2024 - Varna, Bulgaria
  • X International Scientific Conference
    "Materials Science. Non-Equilibrium Phase Transformations"
    02.-05.09.2024 - Varna, Bulgaria
  • XVII International Conference for Young Researchers
    "Technical Sciences. Industrial Management"
    04.-07.09.2024 - Varna, Bulgaria
  • XXI International Congress
    "Machines. Technologies. Materials"
    Summer session
    04.-07.09.2024 - Varna, Bulgaria
  • IX International Scientific Conference
    "Conserving Soils and Water"
    09.-12.12.2024 - Borovets, Bulgaria
  • VIII International Scientific Conference on Security
    "Confsec"
    09.-12.12.2024 - Borovets, Bulgaria
  • IX International Scientific Conference
    "Industry 4.0"
    Winter session
    11.-14.12.2024 - Borovets, Bulgaria
  • VI International Scientific Conference
    "Mathematical Modeling"
    11.-14.12.2024 - Borovets, Bulgaria

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