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

The problems of heat and moisture transfer, air permeability in single and enclosure constructions (EC) of buildings, facilities and heat, engineering and electrical networks under the influence of environmental factors and the work of heating, ventilation and air conditioning has been analyzed. A general definition of the problem taking into account the transfer processes of internal voluminous or local heat source (drainage) has been considered. A generalized mathematical model (MM) of unsteady heat and mass transfer process for bodies of different canonical form (half-plate, hollow cylinder and sphere) and their analogues has been developed. In particular cases of the mathematical model, the dependence of the physical characteristics of the (solid isotropic) medium, the boundary conditions parameters, the capacity of the mass substance transfer sources (drains) from the transfer potentials (temperature, moisture content) or the space-time continuum has been taken into consideration. The analytical solution of the generalized non-stationary and stationary heat and mass transfer problem under the general boundary conditions of different (first, second, third and mixed) kind on the outline of the researched area has been scrutinized. For constant system parameters of non-stationary transfer processes an algorithm for solving differential transfer equations using Fourier transformation with variable parameters of different kind of boundary conditions has been shown. For large-scale transitions, practical applications, parametric analysis of the solutions obtained, setting optimization and automation tasks for process control systems, the obtained MM, analytical and approximate solutions of direct transfer short circuits are given a criterion form convenient for these purposes.

The necessity of using the apparatus of mathematical statistics to obtain high reliability of the results of the evaluation of thereliability indicators of agricultural machinery in comparative tests is justified.
Two models of plant protection machines have been tested and the main numerical characteristics of the indicator production till failure of the failure-free feature have been obtained.
The application of the Student’s criterion for proving the statistical significance of the difference in the tested reliability indicator is justified.

The types of machine reliability tests and the applicability of the test plans are discussed. On this basis, a methodology for experimental testing of the reliability of the machines is proposed and the interrelation of the elements of the methodology is shown.

In scientific view, an innovative economy is an economy that is based on knowledge, new achievements in science, technology and highly intellectual capital. The article defines the main components of the innovative economy, each of which reaches a competitive level according to international criteria: first of all, it is innovative potential; institutional innovation system; innovative infrastructure and highly organized forms of interaction of economic entities, including innovation centers, technoparks, technopolises, clusters, venture business and others; favorable environment for human capital growth. In the course of the study, we have given scientific credence to the indicators of innovative development of economy, criteria and indicators for assessing innovative nature of production, innovation activity at the levels of enterprises, organizations, territories, as well as indicators of innovation commitment of economy and the effectiveness of innovative processes.

The factors effecting evaluation of industrial enterprises` business plan risks have been defined. Types of risks, their characteristics and insurance forms have been studied amid current business environment. It has been pointed out that the criteria themselves are not enough to accept a project by an industrial enterprise. It has been proved that project`s decision making has to meet all the criteria and stakeholders’ interests of an investment project. The criteria based on value changes over time, which can be taken into account when evaluating comparable amounts of money separated by time, have been suggested.

Insuring a sustainable development of wind energy production and consumption is challenging and highly important for /achieving of EU 20/20/20 goals for Bulgaria. Wind energy has been seen as a clean and environmentally friendly in comparison with conventional energy sources, but there are still some conflicts between wind energy project development and environmental protection goals that should be enlighten and solved. One possible way is to enhance the process of wind energy projects’ location identification. The current research is focused on identification and classification of criterion that could be used in this process. The legal requirements regarding wind energy projects’ location are analyzed and presented. Additional requirements regarding environmental protection and biodiversity conservation are identified and defined as criterion. A set of measurable indicators related to each criteria is established and proposed in this paper.

The article deals with determining of fatigue lifetime of structural materials during by multiaxial cyclic loading. The theoretical part deals with the fatigue and with criteria for evaluation of multiaxial fatigue lifetime, especially Fatemi-Socie, Smith-Watson-Topper, Brown-Miller and Liu. The experimental part deals with testing of specimens for identification of the strain-life behaviour of material and determining the number of cycles to fracture of aluminium alloy for phase shift 0° and 90°. Extensive fatigue experiments were conducted using 6063.T66 aluminium alloy under multiaxial bending-torsion loading.

Разгледани са предвидените в законовата уредба критерии за оценка на оферти по Закона за обществените поръчки и са анализирани предимствата и нодостатъците им при провеждане на процедури за закупуване на трактори и самоходна земеделска техника. Разработена е методика за комплексна оценка на офертите по критерия – икономически най-изгодна оферта, базирана на обективни технически и икономически критерии. Така определената комплексна оценка позволява в максимална степен да се отчете влиянието на всеки компонент в нея при запазване на предварително определената му тежест.

Investigation and assessment of non-lethal weapons (NLWs) require development of specific methods and tools different than those applied to conventional weapons, due to reversibility and limited duration of the NLWs’ effects. The capabilities evaluation aims to establish to what extent the NLWs are able to meet the requirements of an operational task. The paper describes the criteria currently applied for assessing the NLWs capabilities and proposes an approach based on selection of criteria and variation of their relative weights depending on studied NLWs and operational tasks specific. The application of this approach is illustrated by a comparative evaluation of a group of non-lethal hand grenades with different effects.