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

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.

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.

A summary study of the development of solar energy and the main factors determining the productivity of photovoltaic systems has been carried out. The predominant surface contaminants of solar panels, reducing the efficiency of photovoltaic installations, and the existing different design types of cleaning systems for their effective removal are examined. The main trends in the development of singlelayer and multi-layer hydrophobic and other oxide coatings with diverse performance indicators suitable for solar panels are traced. In laboratory conditions, experimental self-cleaning coatings (based on compositions with the participation of Y2O3 and ZrO2) deposited by the sol-gel method on vitreous samples were obtained. The structure and morphology of the prepared thin films and the technological conditions for the deposition of nanoscale layers with different functional characteristics were investigated. The experimental results represent a prerequisite for the development of a series of additional compositions and a detailed technological regime for obtaining various modifications of resistant, long-lasting self-cleaning coatings, potentially applicable to photovoltaic panels.

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.

One-component CeO2 coatings and bi-component CeO2/ZrO2 multilayer coatings were obtained by a sol gel process. The phase composition, surface morphology and roughness of the samples were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Atomic force microscopy (AFM) and X-ray scanning electron microscopy (XPS). The corrosion resistance and protective ability were characterized by using salty solution of 3.5% NaCl at 25 C. The multilayer configuration of CeO2 and ZrO2 ensure enhanced protection of the steel in comparison to the single CeO2 coatings and uncoated steel. The surface morphology and anticorrosion properties depend significantly on the treatment temperature of both CeO2 underlayer and ZrO2 top layer. At lower treatment temperatures, they are relatively dense and smooth. The corrosion resistance of the multilayers slows down, when ZrO2 coatings were heated above 500oC. This probably is due to the more pronounced crystallization of cubic zirconium dioxide, resulting in deeper boundaries between the individual grains. The protective properties of a CeO2/ZrO2 multilayers could be attributed to the low crystallized structure with very fine crystallites.

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.

They have been conducted on ellipsometry and contact angles. The contact angles of a surface coating on glasses applied in photovoltaics were measured. This study used a DSA 100-Expert (Krüss GmbH, Germany) to measure contact angles on glass substrates. Contact angles were measured using the DSA 100-Expert tilt table accessory to identify both advancing and receding contact angles. A drop of deionized water is deposited on the glass substrate and then the table is tilted at a constant rate of 5 degrees per minute, to a tilt angle of 90 degrees.

In this paper, we present the results of atomic force microscopy (AFM) characterizing the surface morphology of nanostructured coatings on photovoltaic glass obtained by the sol-gel method. Two organic titanium precursors were used to prepare the TiO2 deposition solution: Titanium isopropoxide (TTIP) and titanium tetrabutoxide – Ti (OC4H9). The hydrolyzing agent is distilled water and the stabilizer is nitric acid /HNO3/and acetylacetone (AcAc). Many samples were obtained at different ratios of the components involved, rate of application of the solution on the glass substrate, and different curing and holding temperatures. The samples were characterized by AFM analysis.

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.

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.

A solution was synthesized in a system ZrO2-CeO2 by sol-gel synthesis and deposited by the immersion method. The pretreated Nb substrate was treated with sulfuric acid and absolute alcohol solutions. Layering was in three stages. The sample was heat treated at 500°C. The obtained results are characterized by XRD, XPS, CEM analyzes.

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.