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

The article briefly presents the possibilities of the created and verified model of polymer plasticization during injection molding. Exemplary characteristics generated by the model are presented and examples of applications of the described model for supporting the design of plasticizing systems of injection molding machines are indicated.

Urbanization and population growth in cities around the world have increased the degree of motorization, which ultimately results in congestion of the transport network within these cities. Traffic simulation tools are essential for the optimization and evaluation of variant solutions in road traffic. By analysing traffic parameters from simulation results it can be decided which variant solution is optimal without high financial inputs. In this paper, the most important simulation tools are explained. As a case study, one district in the City of Zagreb was chosen to present possibilities of simulation tools and their implementation in the evaluation of traffic solutions.

New area industry of Albania, in recent years, factories with closed cycle of production and processing of aluminium alloys are being targeted. In Albania about 25,000 tons of aluminum alloys per year are produced and there is a tendency to increase this production. This reality has encouraged us to undertake a number of studies with the primary objective for optimizing the parameters of the basic process of this industry. In this article we focus on the process of artificially aging aluminum alloys. From early and newer studies [2], the importance and delicacy of temperature-time parameters in the evolution of microstructure and in the mechanical properties of the final product are recognized and underlined. We have impost an experimental planning based on the Response Surface Method by choosing Central Composite Design to optimize the temperature and time parameters for the artificial aging with the object ive of maximizing the process indicator – mechanical properties, hardness in our case. The plan includes 13 tests with 5 replicas in the center of the experiment, built with the help of Design-Expert DX7 and DX13 software. The focus of our attention was the assesment of the design, analysis of residuals and diagnostic diagrams and forms of presentation of results: mathematical model, 3D response surface, isocontours and effects of interaction between factors. In the future works we will present the experimental results of the optimization of the artificial aging process for different aluminium alloys produced in Albania.

The population of the city of Tirana is getting bigger. Transportation in this city has become extremely heavy. Many of its citizens choose to move using their vehicles thus causing an overcrowded traffic. It has happened to all of us to get stuck in the traffic of Tirana, to be late for our destinations and to be stressed by that chaos.
The use of public transport would be a successful way of reducing the traffic. In this paper we have treated Dijkstra Algorithm and its application in railway system of transport for the proposed Tram system for the city of Tirana. Considering the expansion(map) and relief of this city, we think that it is very favorable to build a tram system in this city. The results of this paper help to have a clear idea of the construction of the tram and a prediction of how it will work and how much it can facilitate the traffic in Tirana.

In this paper is performed exergy analysis of high pressure feed water heating system and all of its components which operates in nuclear power plant. Four cases are observed: system operation in the base case and system operation in three optimized cases. Exergy analysis show that optimization by using different algorithms has a different influence on the exergy destructions, while all the algorithms increase whole system and its components exergy efficiencies. An increase in the ambient temperature increases exergy destructions and decrease exergy efficiencies of the whole observed system and its components, regardless of operation case. The highest exergy efficiency of the whole analyzed system is 96.12% and is obtained by using an IGSA algorithm at the lowest observed ambient temperature of 5 °C. By observing exergy destructions only, it should be noted that GA and IGSA algorithms give almost identical results.

This article describes the entropy method optimization based on the approach of minimal increase of entropy in the thermodynamic system. Here is presented the experimental set up of flat plate solar collector with liquid as working medium, effective absorber area of the collector 1,4 m2, absorber plate of aluminum, copper pipes and selective coating. A comparative analysis is conducted between the efficiency of a theoretical model of nonisothermal solar collector and the efficiency obtained by measuring the physical model of a solar collector. Results show a general trend of growth the collector efficiency due to the reduction of irreversibility of the represented processes.

The paper theoretically substantiates and practically implements mathematical methods of modeling production systems, proves the adequacy of mathematical models and optimization methods, as well as selected rational optimization methods and created software that implements the selected methods in practice. The analysis of methods of modeling and optimization of production technological systems is performed, the most effective methods of solving these problems for discrete production are selected. The main provisions of infinite-valued logic and ordinal determinants, on which the structural-logical approach to the study of complex systems, which include production systems in instrument making, are considered.

Over the last two decades, polymer electrolyte membrane fuel cell technology has been increasing its share in power generation systems. In this work, the basic polymer electrolyte membrane fuel cell (PEMFC) system operation is presented first. Some most controloriented modeling approaches are reviewed as the model is essential for further control. Optimal control of such a system can improve efficiency and hence reduce the cost of ownership. The objective of this work is to present the concept of control and depict some of the possible applications of PEMFC systems

This article discusses the features of automation of discrete manufacturing processes. The peculiarities of application of industrial robots are analyzed. Emethod proposed for the study of roll-over systems, which allows the choice of the optimal solution under specific conditions

For the development of new engines, as well as to obtain the correct results from mathematical modeling, numerical methods should be used, with the help of which verification of mathematical models takes place. This approach can significantly reduce the material and time costs at the development stage. The influence of the optimization method used in processing the experimental data of engine indexing to obtain semi-empirical coefficients of the form Wiebe is explored. A comparison is made of the rate of calculation of the coefficients of the Wiebe formula using brute force and gradient methods. In both methods, the integral using the modulus of the difference between squares of the experimental and calculated dependences is chosen as the target function. Analysis of the rate of calculation of the coefficients of the Wiebe formula showed the need to use the combined use of both methods: the global minimum of the objective function by the method of brute force with a large step and near the optimal point – the gradient method

This paper presents an experimental study related to the optimization of cutting parameters in roughing turning of AISI 1045 steel under flooded conditions. The aim is to find a suitable combination of cutting parameters (cutting speed, depth of cut and feed rate) that minimize specific cutting energy and maximize material removal rate. The machining experiments were performed based on the Taguchi L27 full-factorial orthogonal array and response surface methodology (RSM) has been used to obtain the regression model for the specific cutting energy and material removal rate. Analysis of variance (ANOVA) was used to find out the significance of each cutting parameter. Finally, the developed models were interfaced with an artificial bee colony (ABC) to determine the optimal set of cutting parameters.

The intensity of aging and wear of the components /aggregates and assemblies/ of the machines is different and hence the necessity of carrying out repair service interventions has different periodicity and volume.
A model has been developed to optimize the periodicity of maintenance of machine components, taking into account the losses from the underuse of their resource.
The influence of the parameters of the law and the economic indicators on the optimal periodicity of the maintenance was examined at the density of the distribution of work until failure to the Weibull distribution.