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

Mathematical modeling is the key parameter in designing new devices. Renewable energy technologies are getting higher importance in the near future. Mathematical modeling of circulating fluidized bed (CFB) biomass combustion could improve both their design and operation, reduce any associated problems and facilitate the implantation of this technology. A good understanding of the combustion and pollutant generating processes in the gasifier can greatly avoid costly upsets. Presently, there is a focus on developing models of CFB for burning biomass and waste material. The objectives of these models are to be able to predict the behavior with respect to the combustion efficiency, fouling problems and pollutant emissions performance of different fuels or mixtures in commercial CFBs. In this study, importance of mathematical modeling in designing CFB biomass gasifiers is investigated in view of innovative solutions.

The main objective of this paper is to develop and calibrate traffic synthetic model for forecasting traffic demand in Anamorava region. The model on existing situation is developed based on “meta model” which uses PTV Visum software. In order to set up a model were taken into account input variables number of residents, number of people employed, working places available as well as the traffic volume entering and exiting this region at “peak hour”. With intention to have traffic volumes as an outcome expressed as AADT, correction coefficients are applied. Multiplying the traffic volumes with correction coefficient there is traffic demand gained for the period of 24 hours which is an indicator to be used for comparison of results. In order to get the reliable model for forecasting, calibration of it is done through TFlow Fuzzy algorithm technique based on GEH test, R2 and percentage deviation criterions. Once the level is completed satisfactory, the final model can be used to forecast the traffic demand for this region.

The study of technological methods of plastic structure formation is an urgent task. Taking into account that structure formation depends on many factors and, first of all, on the deformed state, studies of the deformed state and structural studies involving TEM were carried out in the work. It is known that reliable data of the structural state allows predicting the mechanical and operational properties of the obtained semi-finished products and products. In this regard, the analysis of the effect of the processing route (C, Bc) on the structural changes after high-cycle active bending was carried out. A numerical simulation of the active bending process was also carried out, and the accumulated strain values were determined for 8 processing cycles. Established patterns of structure formation, depending on the level of accumulated deformation and processing route.

Comparison of numerical methods for modeling the impact of an explosion on a metal plate such as LOAD_BLAST; LOAD_BLAST_ENHANCED; Arbitrary Lagrangian-Eulerian; Particle Blast Method; Smooth Particle Hydrodynamics which are implemented in the program LS-DYNA. The adequacy and accuracy of these methods are evaluated depending on the distance ratio to the explosive charge. The advantages and disadvantages of each method and recommendations for their use based on the results of this modeling and the experience of the authors of thisarticleare presented..

This paper deals with dynamic analysis of bridge crane with one main girder during telpher motion in order to determine dynamic behavior and oscillations while carrying full load. During the telpher motion the main girders and side girders are heavy loaded parts while they undergo forces, moments and oscillations from lifting mechanism that carries workload. The method of analysis is the comparison of results gained through modeling and simulation and experimental measurements. The analysis will be concentrated in finding the nature of dynamic forces, moments and stresses that acts on main crane’s parts and finding the extent and form of oscillations that can cause damage and failures. Also the interest is to study the effects of load swinging in crane’s stability. Results will be shown in the form of diagrams as the solution results of the tested system. Crane is modeled from standard manufacturer, as a special type of Bridge Crane with one main girder and telpher. Conclusions of these analyses are useful for design considerations, dynamic behavior and safety.

In this work a model of a truck when braking is created. The model takes into account the deflections in the suspension and vibrations of the sprung mass. The differential equations of the model are worked out. Numerical experiments are performed and some results are given. It is shown that if the shock absorber damping ratio is increased when vehicle braking, it is possible to reduce the pitch angle and the jounces in the suspension.

A review of the existing methods applied to multi-criteria decision aiding has been made as well as the multi-criteria approach to a class of problems in the field of material science has been defined. The multi-criteria decision aiding has been successfully applied to determine appropriate compromise decisions about the examined parameters of a number of technological processes of welding, chemical thermal processing, iron covering, etc. The approach presented determines the values of technological factors satisfying the requirements of users simultaneously to a number of values examined and proposes a solution for the relatively highest thresholds at one and the same time

In the paper are presented the main theoretical techniques used for the modeling and simulation of industrial processes. The main focus is on the physical side of the theoretical techniques and their mathematical side is reduced to a reasonable minimum. Different theoretical approximations as thermodynamic and hydrodynamic levels are used.

Cities are faced with many challenges, in particular in relation to the mobility of people and the structure of land-use. Parking management, which makes the link between the fields of urban planning and transportation, is one of the crucial ways to meet these challenges.

The problem of parking in the capital of Kosovo in Prishtina is a major concern for the citizens and central and local authorities. For the purpose of easier parking problem study, the first ring of the center zone of Prishtina is divided into XI sub zones. During the collection of data directly from XI sub zones through the observation- survey method, it was noted that the biggest problems are in the sub zones II. Therefore, in this paper is analyzed sub zone II through the parking statistics such as parking causes, accumulation, parking loads, parking duration. After the analysis, findings are made on the choice of the parking problem for this sub zones.

This paper discusses the research methodologies utilized for developing a suspension system for a four wheel-drive terrain vehicles. The main research methods can be identified as literature studies; design processes by applying CAD systems, numerical analyses methods, mathematical modeling and simulation, optimization of the mechanical systems, as well as the comparison, analysis, and evaluation of the obtained results. The proposed suspension system for the terrain vehicle was successfully derived at from a classic double wishbone control arm. Optimization of the suspension parameters for passive ones is performed by Multi Objective Genetic Algorithms, whilst for active damping force by employing Hooke-Jeeves non-linear programming method. On the basis of comprehensive analysis it is shown the active systems are more adequate. The proposed suspension design provides relatively small lateral wheel motion, zero camber angles, and effectively absorbs the vibrations caused by road excitation.

The research covers the usage of the random numbers in Monte Carlo simulations for air pollution models. Two new random number generators are developed; their strengths are compared with the existing random number generators. The results in this paper showed that the two newly developed random number generators achieved better results on a basis of failed test, however it extended the time for generating random numbers. In future we plan to use the newly developed random generators for filling the missing values in the measurements.

This paper deals with dynamic analysis of particular type Construction Cranes known as tower crane during rotational motion of its jib. Methodology of analysis consists of Schematic Design of model, which implements schemes with block diagrams to analyze cranes and their parts during particular work cycle. This procedure consists of crane model development of interconnected elements that represents crane parts, 3-D visualization and simulation of motion. Analysis will be carried out through simulations, and solution of Euler differential equations of second order gained from schematic model. Dynamic parameters investigated are: acceleration, angular velocity, forces and torques in main parts of crane, and influence of load swinging. Diagrams will be presented for main parts of crane as the solution results of the analyzed system. Results gained will be used to get conclusions about dynamic behavior of crane, present graphs of main parameters and search for regulation of optimal jib rotation. Analysis will be done using modeling and simulations with computer application MapleSim. Also, results gained from simulations will be compared with those from experimental measurements.