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

Calculation of thermal diffusion and filtration fluxes at the interface by “traditional” methods requires preliminary determination of the potential values (concentration, moisture content, temperature, pressure) in the four-dimensional space of events. Such methods for solving boundary value problems, which provide “extra” information for technical calculations, are usually very laborous and require the use of numerical methods that are not always convenient in engineering practice. The proposed fieldless calculation method allows one to determine on the boundary of the region the gradients from the transfer potentials and, consequently, energy and material flows in the form of a known functional of the potentials at the interface at their short-term contact directly on the matrix of transfer coefficients of the formalized boundary value problem. This method uses the fractional index differentiation operation (fractional differentiation) and is convenient for solving limiting boundary value problems, i.e. when the characteristic size of the contacting phases in the boundary conditions of boundary value problems tends to infinity or the time of their interaction tends to zero.

Using the methods of systemic, mathematical and numerical analysis, as well as general physicochemical and thermodynamic laws, a complex of theoretical and experimental studies of transfer processes during short-term contact of phases has been carried out. These studies made it possible to fully reveal the regularities of external and internal heat and mass transfer, to find scientifically grounded ways to intensify the processes of vacuum, conductive and combined drying methods. Within the framework of linear nonequilibrium thermodynamics, a mathematical model of filtration-diffusion energy and mass transfer has been developed with a correct estimate of the orders of the terms in the system of differential equations of energy and mass transfer, taking into account the composition of the vapor-air mixture in the capillary-porous body. The limits of applicability of the hypothesis of short-term contact of phases according to the Fourier criterion for the transfer inside and outside the surfaces of the canonical shape (plate, cylinder, sphere) and wedge are estimated from the standpoint of the accuracy of calculating interphase flows. It is shown that in a number of cases the contact is not short-lived due to the curvature and the presence of angles on the contact surface, and not due to the finiteness of the dimensions of the contacting phases.

The analysis of the theoretical studies carried out on the technological process of the hydraulic ram method of water lifting from watercourses to improve the design and technological scheme of a hydraulic ram pumping unit is given.
The design and technological scheme of an improved hydraulic ram pumping unit developed at Kazakh National Agrarian Research University for water lifting from watercourses for watering pastures and irrigation of land plots of peasant and farm farms of the agro–industrial complex of the Republic of Kazakhstan is presented and theoretical prerequisites for determining the main parameters of a hydraulic ram pumping unit and the main criteria for their improvement are given.

The development and use of mathematical models is of great importance not only in the research field, but also in the practical field. Mathematical research in psychology is based on the construction of an image of the studied object or group of objects, fixing the basic properties and relationships. The complexity lies in the heterogeneous nature of individuals, in the diversity of their behavioral characteristics, interests, and features of social behavior. Statistical models can be divided into separate groups; models that consider processes that affect individual behavior at the micro level, that is, at the level of low-level human thinking processes; meso-level models; macro-level models that consider and predict general trends in the behavior of people in a group, for example, in a crowd.

The trend of using micro-parts in modern industry puts new tasks for contemporary production technologies. If these parts are made of difficult-to-machine materials, machining problems become more complicated. On the other hand, the requirements go towards manageable and stable production processes, reduction of the processes number, reduction of the machining cost, using of clean technologies, etc. Use of mechanical solid tools in engineering materials micro-machining, many problems occur, such as: high machined surface roughness of the, tool deflection, intensive tool wear, etc. These problems lead to difficulties in establishing adequate process models, and thus the ability to control of micro-milling process and it’s including in smart processes and smart factory concepts. This paper presents the possibilities of using micro-milling in the difficult-to-process materials machining. The phenomena in micro-cutting are analysed, as well as the output machinability indicators (surface roughness, tool wear, etc.). As a conclusion, guidelines and technological frameworks for the application of micro-milling in practice are given.

Photovoltaic thermal system (PV-T) converts sunlight into electricity and heat simultaneously. The overall efficiency of these systems is higher than the efficiencies of PV panels and solar collectors together. In Albania energy production from photovoltaic systems has been promoted in the recent years. Albania’s Mediterranean climate conditions are very favourable for investment in renewable energy systems. In this study a stand-alone 280 W PV-T panel is considered with respect to thermal analysis of the system. The panel is installed at the terrace of the building University in Tirana, Albania. The aim of this work is to present the temperature profile of the panel, since there is a correlation between efficiency and temperature. In order to analyse the temperature distribution on the panel surface a series of experiments are carried out. Temperature variation vs. time for different water flow rate was performed. The inlet and outlet water temperature profile is drawn in this article.

The study is a review of the scientific and applied content of the research carried out over the years on the topic, both worldwide and by the authors. The research is structured in a way that presents the topic in its active development over the years, which substantially proves its permanent relevance. The development of the researches of the spatial transformation of motions, oriented towards the synthesis and analysis of spatial transmissions with innovative characteristics, at this stage and up to the present moment for Bulgaria are realized exclusively at the Institute of Mechanics at Bulgarian Academy of Sciences (BAS). The content of the researches carried out at the Bulgarian Academy of Sciences clearly determines their market orientation and, therefore, their place of development was in the “Centre of competence MIRACle – Mechatronics, Innovation, Robotics, Automation, Clean Technologies” at the Institute of Mechanics. The above said makes it inexplicable the decision of the former management of the institute, in the face of Prof. Vasil Kavardjikov (Director) and Assoc. Detelina Ignatova (Project Manager), to ignore this topic when designing a project for the creation of the Competence Centre.

The possibilities of using the investment potential of industrial enterprises are investigated. The expediency of formation of investment potential of industrial enterprises is substantiated. The methods and procedure for assessing the effectiveness of the investment potential of the enterprise are analyzed. The organization of the system for managing the efficiency of the investment potential of an industrial enterprise is proposed.

Risk management constitutes currently one of the most important elements of the management of an enterprise, which is crucial to its security and continuous improvement. This is a several-stage process, and its implementation should systematic and principled in character. The article sets out the risk assessment for activities performed in conjunction with individual operations of a manufacturing process, and specifically, the book production process. The risk assessment was preceded by the identification of hazards to technological, transport and control operations, followed by their analysis using an indicator method. Operations have been identified, which are characterized by the highest risk, and preventive and prophylactic actions using various control measures (technical, organizational, legal, individual and collective) have been proposed. Risk assessment for a task is a primary outline for the use and implementation of risk management issues that go beyond the commercial risk assessment in an enterprise.

The article provides an analysis of the excitation conditions and the results of the detuning of parametric resonance in mechanical drive amphibious water-jet machines. The paper substantiates the possibility of solving the problem of reducing the dynamic load on the basis of the synthesis filter low-frequency vibrations.

Prevention of industrial accidents in Europe and creation readiness of the authorities and the community for countering them are aimed not only at major catastrophes, but also at the small ones, which threaten the society, jobs and environment. Regardless of the internationally accepted framework for prevention and counteraction the industrial accidents involving hazardous substances (refers to the Seveso type site/area related accidents), there are fields that have not yet been developed, such as an assessment of the vulnerability of various sectors of economy, their interdependencies and the impact on social life. Considering these challenges, the main objective of the current article is to bring to the attention of stakeholders an integrated package of advanced developments, both in terms of Seveso type site/area related accidents, caused by reason of technological failures (technological mistakes) or are due to targeted man-made activities (terrorism).