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Keyword: sound insulation

  • MATHEMATICAL MODELLING OF TECHNOLOGICAL PROCESSES AND SYSTEMS

    Study of the thermal and sound insulation properties of ceramic plates with cavities designed for beehives

    • Lyuben Lakov
    • Yonka Ivanova
    • Todor Partalin
    • Mihaela Aleksandrova
    • Todorka Lepkova
    • Gergana Mutafchieva
    Mathematical Modeling, Vol. 5 (2021), Issue 2, pg(s) 59-61
    • Abstract
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    •  Article PDF

    The article presents a study of the sound and thermal insulation properties of ceramic plates with cavities, designed for beehives. The plates are obtained by the “casting” method from a water-dispersed colloidal system based on a patent-protected quartz glass-ceramic. They are composed of amorphous SiO2, mullite and cristobalite. To measure the thermal conductivity, a thermal chamber is constructed with a heater installed in it. Given that the heat flow passing through the three-layer ceramic plate for beehives is constant, the temperature difference between the two opposite sides of the plate at steady state (at constant heat flow) is measured and the thermal conductivity is calculated. A two-chamber method is used to determine the sound insulation capacity of the ceramic plates for beehives. The sound pressure of the sound waves – the incident one and of the wave which has passed through the sample –is measured in the frequency range from 100 to 3150 Hz

  • DOMINANT TECHNOLOGIES IN “INDUSTRY 4.0”

    Study of sound absorption and reflection coefficients and thermal conductivity of porous composite material obtained from household glass waste and burnt rice grains husks

    • Luben Lakov
    • Yonka Ivanova
    Industry 4.0, Vol. 5 (2020), Issue 5, pg(s) 227-229
    • Abstract
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    The coefficients of sound absorption and reflection in the frequency range up to 2 kHz, here respectively 0.2 and 08, as well as the coefficient of thermal conductivity, here below 0.027, of a new porous composite material were studied. The material was obtained from ground household glass waste and rice grains husks burned at temperature from 4000C to 7000C. The results show that the material has good sound reflectivity and low thermal conductivity, which makes it suitable for the manufacture of modules for thermal and sound insulation.

  • 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

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