International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

  • Journals
  • Submission
  • Events
  • About us
  • Contact

Author: Krasimira Toncheva

  • BUSINESS

    Building eco-friendly houses with construction coatings, bricks and panels based on sedimentary rocks

    • Lyuben Lakov
    • Krasimira Toncheva
    • Marieta Gacheva
    • Mariya Georgieva
    Science. Business. Society., Vol. 10 (2025), Issue 1, pg(s) 9-12
    • Abstract
    • View Article
    •  Article PDF

    In the development of new composite structural elements based on sedimentary rocks (clays) as inorganic binders and foam composite materials, their physical characteristics are presented for the construction of recipe compositions and the determination of their complex new properties. The role of the components of the compositions, together with organic reinforcing fiber materials such as straw, rice husks and others, basic parameters of the technological regime and other factors for ensuring adequate workability of the prepared composite compositions for obtaining building coatings and elements – bricks and panels for building ecological houses – is considered. The determination of the necessary technological characteristics of the composite mixtures ensures their effectiveness.

  • DOMINANT TECHNOLOGIES IN “INDUSTRY 4.0”

    Structural and technological aspects of the production of ceramic beehives

    • Lyuben Lakov
    • Bojidar Jivov
    • Todorka Lepkova
    • Krasimira Toncheva
    • Dimo Mihaylov
    Industry 4.0, Vol. 9 (2024), Issue 6, pg(s) 220-223
    • Abstract
    • View Article
    •  Article PDF

    Applied research work carried out for the development and manufacture of an innovative movable frame ceramic hive with increased operational stability and efficiency is presented. A brief justification of the design solutions used and the choice of the applied technological approach is made. The main stages of the developed technological regime for the preparation of structural ceramic elements and various modifications of experimental prototypes are discussed in a summarized form. The existing possibilities for the production of new modifications of ceramic beehives with improved performance chracteristics by applying different technological approaches are analyzed. The technological regime for the preparation of structural details is fully compatible with the production methods typical for the ceramic industry and provides the opportunity for further implementation.

  • TECHNOLOGIES

    Installation and method for obtaining amorphous SiO2 from rice husks

    • Lyuben Lakov
    • Bojidar Jivov
    • Krasimira Toncheva
    • Marieta Gacheva
    Machines. Technologies. Materials., Vol. 18 (2024), Issue 7, pg(s) 224-226
    • Abstract
    • View Article
    •  Article PDF

    An original installation and method for the preparation of ash with a predominant content of amorphous SiO2 (96-97 %), which is a technological residue after thermal treatment of agro-biological waste (rice husks), are presented. The resulting product is a complete raw material for the production of materials with a variety of functional characteristics, using different technological designs (in combination with other components). The design parameters of the installation and the different stages of the developed technological approach are discussed. The basic operating mode of the installation within one operating cycle is presented. The design features and technical equipment of the installation allow controlled creation, maintenance and modification of the necessary technological conditions for the effective thermal processing of the waste biomass.

  • MACHINES

    Device and technology for the production of foam granules of “breathable” composite material based on heat-treated rice husks

    • Lyuben Lakov
    • Bojidar Jivov
    • Marieta Gacheva
    • Krasimira Toncheva
    Machines. Technologies. Materials., Vol. 18 (2024), Issue 4, pg(s) 114-117
    • Abstract
    • View Article
    •  Article PDF

    An innovative device and a cost-effective and environmentally friendly technology have been developed to produce porous composite materials by using two types of waste raw materials: residual biomass from agricultural production and municipal waste. Heattreated rice husk and ground waste glass were used as main components. The technological approach presented here allows for the preparation of “breathable” porous materials with the predominant presence of open pores and increased specific surface area. A promising possibility for the application of the developed materials is their use in bulk or in the preparation of various composite building elements based on inorganic binders. Recipes and an adequate technological regime have been developed taking into account the design characteristics of the production facility, the specificity of the waste raw materials used and the intended target performance of the products.

  • TECHNOLOGIES

    Investigation of composite building elements in a real environment

    • Krasimira Toncheva
    Machines. Technologies. Materials., Vol. 18 (2024), Issue 3, pg(s) 100-104
    • Abstract
    • View Article
    •  Article PDF

    A study was carried out on the incorporation in a real enirontment of fabricated innovative building elements. The investigated elements include products such as rectangular plates, “П” and semi “O” shaped elements, all made of composite material consisting of spherical foam glass granules bonded with a suitable multi-component cement mixture and manufactured by a specially developed technology. The elements have a specific shape, dimensions and particular physical and mechanical characteristics, thermal and acoustic insulation properties and fire-resistant qualities. The aim of the study is to incorporate them into given construction objects, mainly buildings, and to determine the efficiency and efficacy of the process of incorporating the building elements into a real building structure

  • TECHNOLOGIES

    Technological characteristics of composite mixtures for the preparation of thermal insulation structural elements

    • Lyuben Lakov
    • Krasimira Toncheva
    • Bojidar Jivov
    • Marieta Gacheva
    • Gabriel Peev
    • Dimo Mihaylov
    Machines. Technologies. Materials., Vol. 18 (2024), Issue 1, pg(s) 21-24
    • Abstract
    • View Article
    •  Article PDF

    The technological characteristics of suspensions used in the development of new thermal insulation composite structural elements based on foam materials and inorganic binders (Portland cement) are investigated. The role of the components of the compositions, the parameters of the technological regime and other factors in ensuring adequate workability of the prepared cementitious solutions is considered. Determination of the necessary technological characteristics of composite mixtures ensures their effective distribution in the formwork moulds when forming the specimens, cost-effective performance at production stage and obtaining products with the planned
    functional properties. The existing opportunities for potential application in modern construction of the developed composite elements are analyzed.

  • MACHINES

    Innovative mill complex for processing glass waste, applicable to the production of foam glass and composite materials

    • Krasimira Toncheva
    • Lуubеn Lakov
    • Bojidar Jivov
    Machines. Technologies. Materials., Vol. 17 (2023), Issue 8, pg(s) 298-301
    • Abstract
    • View Article
    •  Article PDF

    An innovative mill complex has been developed for the processing of glass waste applicable to the production of granular foam glass and fire-resistant, energy-saving, acoustic and thermal insulation composite building elements. The presented design solution is in accordance with the necessary technological characteristics of the ground vitreous raw material for use in the production process. It is envisaged that the grinding will be carried out in two stages and will be combined with homogenization of the batch being prepared. The first stage is the initial grinding of the raw material in a vibrating mill with metal grinding bodies, allowing grinding for a shorter period of time to a certain size of the particles with minimal contamination. In the second stage, the final grinding (up to a technological size of the particles) and homogenization is carried out in a ball mill with non-metallic grinding bodies. The main production equipment necessary for the realization of the presented technological process was considered.

  • MATERIALS

    Production method role for the composite powders quality

    • Krasimira Toncheva
    • Zoya Savova
    • Luben Lakov
    Machines. Technologies. Materials., Vol. 17 (2023), Issue 7, pg(s) 282-284
    • Abstract
    • View Article
    •  Article PDF

    Self-propagating high-temperature synthesis (SHS), refers to a technology for the production of useful materials (mainly composite powders) that uses combustion processes. The solid combustion process results in the release of more heat which is needed to rebond the elements of the system and it is this extra amount of heat that is used to self-sustain the combustion process and its development. This process is known as self-propagating high temperature synthesis.
    This paper presents the study of the magnetic properties of the products obtained by this method in comparison with other methods which use nickel-zinc ferrites. The latter are widely used in radio devices, antennas and transformer cores, as well as in high-frequency filters where the current loss is significant.

  • TECHNOLOGIES

    Optimization of the distribution of spherical granules at the formation of composite structures

    • Georgi Evt. Georgiev
    • Lyuben Lakov
    • Krasimira Toncheva
    • Bojidar Jivov
    Machines. Technologies. Materials., Vol. 17 (2023), Issue 3, pg(s) 117-122
    • Abstract
    • View Article
    •  Article PDF

    On the basis of separate fractions of granular foam glass and inorganic binders, various modifications of heat-insulating composite material have been developed. A promising opportunity for potential application of the material is the preparation of composite elements and profiles suitable for installation around doors and windows during the construction or reconstruction of buildings. In connection with the study of the possibilities for optimal distribution of the granules, various options for their arrangement have been analyzed and evaluated. The mathematical tools of stereometry and 3D computer modeling were used. Visualizations of the obtained structures are presented and their compactness is evaluated. Recommendations are made for the ratio between the sizes and quantities of the granules used in order to achieve maximum density.

  • 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
    • View Article
    •  Article PDF

    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.

  • DOMINANT TECHNOLOGIES IN “INDUSTRY 4.0”

    Heat-insulating lightweight concretes and composite materials on the basis of inorganic binders with application in construction

    • Lуubеn Lakov
    • Bojidar Jivov
    • Mihaela Aleksandrova
    • Stancho Yordanov
    • Krasimira Toncheva
    Industry 4.0, Vol. 8 (2023), Issue 2, pg(s) 47-51
    • Abstract
    • View Article
    •  Article PDF

    A general overview of a number of thermal insulation materials and products made on the basis of inorganic binders (mainly Portland cement) is presented. The technological methods of production, the main operational indicators and the application in construction of various heat-insulating and structural-heat-insulating lightweight concretes are examined. The structure of various cellular concretes (foam concretes and aerated concretes), composite materials and lightweight aggregate concrete was analyzed. The role of the origin, technological processing, characteristics and composition of different types of light additive materials for the formation of the final operational properties of the products has been traced.

  • 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
    • View Article
    •  Article PDF

    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).

  • Previous page
  • You're on page 1
  • 2
  • Next page

    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

    Scientific Technical Union of Mechanical Engineering "Industry-4.0"

    108, Rakovski Str., 1000 Sofia, Bulgaria
    tel. (+359 2) 987 72 90, tel./fax (+359 2) 986 22 40,
    office@stumejournals.com