## Evaluation of Various Cooling Conditions of Vertical Commercial Refrigerator Using Mathematical Modeling

Mathematical Modeling, Vol. 7 (2023), Issue 3, pg(s) 83-86

Commercial kitchen products have a larger capacity than household products and are required to withstand harsh conditions because they are used more intensively. In addition, commercial refrigerators, among these products, are critical for the long-term preservation of food and beverages for many commercial businesses. Commercial refrigerators are generally expected to provide operating conditions between -2ºC and +8ºC. Variations in cooling conditions are observed due to the intensive use of commercial refrigerators in businesses (refrigerator doors being opened too much, irregular placement of different food products, etc.). Therefore, this situation does not allow the commercial refrigerator to be used efficiently. It can also cause food waste. It was first evaluated on a vertical commercial refrigerator using mathematical modeling to eliminate these drawbacks. This study aimed to obtain data to provide the most suitable cooling conditions by evaluating the temperature and air circulation at different points of the vertical commercial refrigerator through simulation studies.

## Mathematical modeling in psychology

Industry 4.0, Vol. 8 (2023), Issue 5, pg(s) 149-151

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.

## Optimization of the distribution of spherical granules at the formation of composite structures

Machines. Technologies. Materials., Vol. 17 (2023), Issue 3, pg(s) 117-122

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.

## MAGMA 6.0 – toolkit and capabilities of the latest version Of the MAGMASOFT software package

Machines. Technologies. Materials., Vol. 17 (2023), Issue 3, pg(s) 108-112

The possibilities for simulation and optimization of foundry technologies using the latest MAGMA6.0 version of the world-famous software package MAGMASOFT are presented. The capabilities of the software are illustrated both for the quick and efficient construction of the 3D geometric models and for the diagnosis of almost all possible defects in a wide range of casting methods. Special attention is paid to the possibilities for autonomous and automatic optimization of casting technologies in order to reduce defects and increase the profitability of castings.

## Optimization of Cooling Performance of Horizontal Commercial Refrigerator Prototype with Mathematical Modeling

Mathematical Modeling, Vol. 6 (2022), Issue 4, pg(s) 118-120

In recent years, the problem of food safety and traceability has been one of the difficulties faced by restaurant and hotel businesses. Food spoilage can occur at any stage of the food chain; most of all food spoilage is due to improper storage conditions in refrigerators. Increasing attention to food quality and safety requires the development of sensitive and reliable analysis methods as well as innovative technologies for maintaining freshness and food quality. Freshness is a factor that has both health qualities and features that affect customer satisfaction and business profitability. Within the scope of this study, simulation studies were carried out to improve the cooling performance with mathematical modeling on a horizontal commercial refrigerator (operating temperature: -2/+8°C) prototype. Along with the original design, evaluations were made with mathematical modeling according to many different variables (temperature, airflow distribution, etc.) that affect the cooling performance, and R&D gains were achieved in developing the prototype according to the most suitable working conditions.

## Analytical model of crowd behavior

Mathematical Modeling, Vol. 6 (2022), Issue 3, pg(s) 90-91

An important task of analyzing the behavior of individuals in society, in a large crowd of people is the development of mathematical models of behavior. The complexity lies in the heterogeneous nature of individuals, in the diversity of their behavioral characteristics, interests, and features of social behavior. Here the possibility of mathematical modeling of crowd behavior is considered and a mathematical model is proposed.

## Investigation of bending strength and modulus of elasticity of a new type of black locust plywood for construction

Mathematical Modeling, Vol. 5 (2021), Issue 3, pg(s) 101-103

The mechanical properties bending strength and modulus of elasticity in bending of a new type plywood for construction, based on black locust wood, have been investigated in relationship with the bonding technological factors. The experimental investigation is based on an optimal composite design with four control factors – temperature, pressure, bonding duration and specific glue consumption. Regression models describing the dependence of bending strength and modulus of elasticity in bending on the investigated technological bonding parameters are estimated. The obtained experimental and model-based results are analysed and discussed

## Kinetic and equilibrium study of the CO2 adsorption on activated carbon

Machines. Technologies. Materials., Vol. 15 (2021), Issue 8, pg(s) 299-302

The presented research are concerned with the modelling of isotherms and chemical kinetics of mass transport for the CO2 adsorption on activated carbon, taking place in the fluidized and fixed bed. To determine the nature of CO2 binding under low-pressure conditions, adsorption complex and thermodynamic effects occurring during the process, four isothermal models were used: Langmuir, Freundlich, Temkin and Halsey. The evaluation of the factors affecting the course and rate of CO2 binding was based on four kinetic models, i.e. pseudo-first-order (PFO), pseudo-second-order (PSO), intraparticle diffusion (IPD) and the Elovich model. The validation of mathematical models showed that the linearized Freundlich and Halsey isotherms models are best suited to empirical data. In the case of process kinetics, the analysis showed that the non-linearized pseudo-first-order model (PFO) proved to be unrivalled in fitting to experimental data. The comparison of two types of tested beds suggested faster kinetics for a fluidized bed, while a larger amount of CO2 at equilibrium was adsorbed by the fixed bed.

## Mathematical modeling of automated production systems

Mathematical Modeling, Vol. 4 (2020), Issue 4, pg(s) 114-120

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.

## THE THEORETICAL ESTIMATION OF THE TRACTOR DRIVE WHEELS SLIPPAGE WITH THE VARIABLE TIRE INFLATION PRESSURE.

Mathematical Modeling, Vol. 2 (2018), Issue 2, pg(s) 69-72

The main tractor parameters that defy suitability of tractors to perform traction work is traction power and driven axle wheel-slide. Different mass tractors wheel-slide on the same soil differs and depends on the vertical load (G), which falls on the driven axle wheels. When choosing tractors and agriculture implements it is needed to foresee the formed implements traction and economical parameters. To achieve this goal mathematical modeling methods are used. The purpose of mathematical modeling is to
determine traction characteristics of the tractor, taking into account various factors. At this moment there are tractor traction models created, that describe various agriculture and field tasks. Most Mathematical models mainly assess the hardness of the soil and driven wheel geometrical parameters. However, one of the most important parameters in assessing the suitability of a tractor unit is the tractors driven wheels slide. To decrease wheel-slide and to increase the driving wheels grip with soil there are different methods being used: Ballast weights, use of twin wheels and changeable air pressure in the tires. However current mathematical models do not consider the change of air pressure in tires. A mathematical module was created, which takes into calculations the driven wheels wheel-slide having different air pressure in the tires.

## EFFECT OF POWDER MODIFIERS ON STRUCTURE FORMATION OF IRON-CARBON ALLOYS

Machines. Technologies. Materials., Vol. 11 (2017), Issue 7, pg(s) 370-372

Effective modification not by expensive nano-powders but by relatively large ones (up to several microns) and capable to dissolve when entering into the melt and become additional crystallization centers at its start point was shown. That provides a metal structure refinement and, consequently, increases the whole complex of mechanical properties. The optimal process parameters of refractory compounds disperse powders modification were proposed.

• ## DETERMINATION OF OIL SPILL PARAMETERS IN THE PROCESS OF OIL AND OIL PRODUCTS SPREADING ON THE WATER SURFACE

The growing marine pollution by oil strengthens the interest not only in the methods of combating their causes, but in methods of their forecasting as well on the basis of modeling and calculation of spreading oil spreading on the sea for some reason or other.

The paper dwells on a mathematical model of calculating the area of oil spill spreading. The developed methodology for calculating change in the radius and area of oil spill is represented by function of three arguments: oil product density ρ , spillover volume V and o spreading time t.

The proposed model allows forecasting the initial stages of oil spreading. The given methodology enables to determine transit time of the process of oil spill spreading from the first phase to the second one, and from the second to the third one, and the radius and area of oil spill spreading.