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of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

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Author: Todorka Lepkova

  • INNOVATIVE SOLUTIONS

    Major operational characteristics of an innovative ceramic beehive

    • Lуubеn Lakov
    • Todorka Lepkova
    • Bojidar Jivov
    • Gergana Mutafchieva
    • Marieta Gacheva
    Innovations, Vol. 11 (2023), Issue 3, pg(s) 86-89
    • Abstract
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    Prototypes of an innovative collapsible beehive, built of long-lasting, structural elements of quartz ceramics with high atmospheric resistance and the presence of air cavities with thermal insulation properties, were prepared. Prescription compositions, an original set of molds, and an adequate heat treatment regime applicable to obtain the structural details were developed. The role of the various technological factors in the formation of the performance indicators of the end products was analyzed. The main characteristics of the prepared experimental prototypes and their major functional advantages in comparison with the existing standard and traditional hives were observed. The presented innovative beehive provides a favorable natural habitat for the normal and safe development of bee families and allows the full application of modern approaches for the efficient and ecological production of high-quality natural apian products.

  • MATERIALS

    Investigation of an appropriate marl raw material for the production of innovative ceramic beehives

    • Todorka Lepkova
    • Lуubеn Lakov
    • Bojidar Jivov
    • Gergana Mutafchieva
    • Marieta Gacheva
    Machines. Technologies. Materials., Vol. 17 (2023), Issue 4, pg(s) 167-170
    • Abstract
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    An observation of the current state of the beekeeping industry and the prevailing main problems was carried out. The prospects for increasing the efficiency and functional capabilities of the bee farms were analyzed. According to the long-term research activity, a technological regulation was contrived for producing innovative ceramic hives. The development is superior to the existing standard beehives made of other materials, in terms of complex operational indicators. The phase composition and technical characteristics of obtained samples of marl raw material (from Bulgarian deposits) were investigated, potentially applicable for the production of various
    modifications of ceramic collapsible hives.

  • TECHNOLOGIES

    Technology and technological scheme of a workshop for the production of beehives made of amorphous quartz ceramics

    • Lyuben Lakov
    • Todorka Lepkova
    • Marieta Gacheva
    • Krasimira Toncheva
    • Gabriel Peev
    • Dimo Mihaylov
    Machines. Technologies. Materials., Vol. 17 (2023), Issue 2, pg(s) 73-75
    • Abstract
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    The development refers to an innovative technology and technological scheme of a workshop for the production of beehives made of amorphous quartz ceramics. The conditions for obtaining stable suspensions from quartz glass are emphasized and investigated. The time for the treatment of the glass in the grinding device, the amount of water, the influence of the modifiers in stabilizing the suspension by adjusting the pH level, as well as the most suitable sedimentary composition of the glass particles are established. The factors determining the speed and degree of sintering of the ceramics are investigated and established. They include the density of the raw products, the dispersion of the quartz glass particles and its purity, as well as the environment in the furnace and the sintering mode.

  • CONSERVING OF THE RESOURCES

    Noise loading in beehives made out of different materials

    • Todorka Lepkova
    • Lyuben Lakov
    Mechanization in agriculture & Conserving of the resources, Vol. 67 (2023), Issue 1, pg(s) 32-34
    • Abstract
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    Bees are highly sensitive to noise pollution and in some cases, noise can impact their behaviour. Towards the goal to create optimal living conditions for the bees, we aim to understand how the material of the beehive impacts the microclimate of the beehive. The present paper aims to examine and compare the noise levels inside beehives of the same construction but made out of different materials. Three 10-frame Dadan-Blatt beehives were used in the experiment – a ceramic beehive made out of high-cavity ceramic tiles of marl clay; a ceramic beehive made out of high-cavity ceramic tiles with increased kaolin content and a wooden beehive (pine). The noise was measured in an urbanized area and inside the beehives. The results show that the best performance in terms of noise insulation is the ceramic beehive with increased kaolin content.

  • TECHNOLOGIES

    Comparison of innovative collapsible ceramic hive and traditional non-separable hives made on the basis of natural plastic raw materials

    • Lуubеn Lakov
    • Bojidar Jivov
    • Todorka Lepkova
    • Krasimira Toncheva
    • Stancho Yordanov
    Machines. Technologies. Materials., Vol. 16 (2022), Issue 10, pg(s) 340-343
    • Abstract
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    An innovative collapsible frame hive was developed, consisting of structural elements made of technical ceramics containing thermal insulation air chambers. Experimental prototypes were prepared using the slip casting method and based on modified recipe compositions, prepared casting molding masses, original gypsum matrices and optimal heat treatment mode. A comparison was performed between the main operational characteristics of the experimental samples and the traditional non-separable hives which have existed throughout history and made primarily of various plant materials and natural plastic raw materials (clays).

  • TECHNOLOGIES

    Financial project for building a technological line and factory for the production of yellow pavers, tiles and other products

    • Krasimira Toncheva
    • Lуubеn Lakov
    • Bojidar Jivov
    • Todorka Lepkova
    Machines. Technologies. Materials., Vol. 16 (2022), Issue 9, pg(s) 307-314
    • Abstract
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    A financial project was presented for the construction of a technological line for the production of high-quality replicas of the socalled “yellow paving stones” and an additional assortment of products with different characteristics based on raw materials originating in Bulgaria. After many years of investigation in laboratory and semi-industrial conditions, polycomponent formulations and an original hightemperature technological regime for the preparation of functional and long-lasting silicate products have been developed. The planned technological approach is in accordance with the existing machine park and the qualification of the industrial production personnel, characteristic of the silicate industry. The main possibilities for the realization of the production are the full restoration of the street areas of the central historical part of Sofia and the construction of long-lasting and aesthetic pavements with a variety of functional purposes in different areas of the capital and other populated areas. The current applied development is oriented towards possible potential producers and investors and various specialists from the field of public infrastructure and cultural-historical heritage.

  • INNOVATIVE SOLUTIONS

    Studing the temperature microclimate in beehives made out of defferent materials

    • Todorka Lepkova
    • Lyuben Lakov
    • Mihaela Aleksandrovа
    Innovations, Vol. 10 (2022), Issue 2, pg(s) 91-92
    • Abstract
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    The use of clay as a structural material has been known for centuries. The authors set the task of studying the applicability of clay as a constructive material in the production of beehives. The study aims to make a comparative analysis of temperature conditions in different types and identical in construction beehives by comparing the indicator for ceramic and wooden hives. For the purpose were used three 10-frame hives type “Dadan-Blat” – two ceramic (one made entirely of marl clay, and the other – with increased kaolin content, both ceramic tiles are with high cavity) and one wooden (pine). Measurements of the air temperature and the temperature inside the hives were made for one month. From the obtained results it is established that for the studied beehives, the ceramic hive with high kaolin content has the best thermal insulation properties.

  • INNOVATIVE SOLUTIONS

    Study of temperature changes in ceramic cavity walls of beehives

    • Lyuben Lakov
    • N. Stoimenov
    • Mihaela Aleksandrova
    • Todorka Lepkova
    • Gergana Mutafchieva
    Innovations, Vol. 9 (2021), Issue 2, pg(s) 78-82
    • Abstract
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    Subject of the present paper is the measurement of temperature changes in the ceramic cavity walls of Dadant Blatt beehives. Using a FLIR P640 infrared camera and two different heat sources, 80 thermogramsof ceramic cavity walls were obtained. The infrared images of the studied objects are divided into rectangular zones. The results of the study are presentedtabularly and graphically.

  • 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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    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

  • MACHINES

    AGRICULTURAL ROBOTS ON THE BASIS OF INDUSTRY 4.0

    • Marin Midilev
    • Ivan Gramatikov
    • Todorka Lepkova
    • Ivanka Martinova
    Machines. Technologies. Materials., Vol. 13 (2019), Issue 12, pg(s) 509-521
    • Abstract
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    Agricultural labor is physically demanding, tedious and often carried out in unfavorable conditions, making it suitable for robotization. Due to climate change and the swift increase of the human populace on Earth, the hunger is becoming increasingly an issue (currently, around 2 billion people suffer from malnourishment). With the aim of maximal efficiency of the production of plant food, an accelerated introduction of robotics in the field of agriculture is required (Agriculture 4.0).

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