Jan Krmela

Trenčianska Univerzita Alexandra Dubčeka v Trenčíne · Faculty of Industrial Technologies in Púchov

The tire is one of the most complex components of the vehicle, which justifies strict standards and regulations set by governments worldwide to ensure the performance, durability, and reliability of tires approved for use in the transport sector. Among these requirements, tire durability testing involves the assessment of short-and long-term tire r...

Considering the present-day environmental and energy objectives set forth by governments and aiming at minimizing carbon footprints and fuel consumption in the transportation sector, it is of utmost importance for manufacturers to enhance tire design. This is because doing so has the potential to revolutionize the automotive industry by promoting a...

Against a backdrop of increasing depletion of natural and energy resources and worsening global warming, the tire industry, like many other industries, is currently confronted with the pressing need to enhance not only its resilience but also the sustainability and cost-effectiveness of its products through advanced numerical simulations. Numerical...

In this paper, we introduce a new vectorized MATLAB-based algorithm for efficient serial computation of global matrix/force arising from finite element method (FEM) for meshes of any type and approximation order in linear elasticity. Because for-loops in MATLAB are very slow, we propose a modified process that takes advantage of vectorization and s...

The article focuses on the computational simulation of polymer composites under biaxial loading. The goal is the quick creation of computational models based on geometry parameters that can be used for biaxial loading simulation. FEA software ANSYS is used for computational simulation. The APDL (Ansys Parametric Design Language) procedure is used t...

This paper presents two improved algorithms for efficient sequential and parallel implementation of the Finite element method (FEM) for both linear and nonlinear boundary value problems. The proposed algorithms address some weak points, such as the overuse of for-loops and serial computing caused by dependencies in constructing fundamental expressi...

The article solves the problem of heat utilization from combustion products in boiler plants. The proposed solution involves extracting heat to preheat the network water for the heating system and implementing additional heat utilization using a liquid-vapor jet apparatus. This will allow for additional working steam generation in the main steam ge...

The current work describes the algorithm for obtaining porous ammonium nitrate granules in granulation plants using devices with different fluidized bed configurations. We present brief theoretical foundations for calculating the main equipment of the granulation plant. We develop and propose the design of individual units for the sequential implem...

The article focuses on computational simulations of basic and specific tests under uniaxial loading of polymeric composites, which are parts of tire casings, based on experimental data using the FEM software ANSYS with the addition of the supporting freeware program CADEC for determination of input material parameters as inputs to the simulations....

This paper is oriented toward the specific testing of polymer composites and textile PA66 cords used as reinforcement for composites. The aim of the research is to validate the proposed new testing methods for low-cyclic testing of polymer composites and PA66 cords for the characterization of material parameters useful as input data for computation...

The modification of polypropylene fibre during their production is usually performed with the aim to improve some end‐use properties of final polypropylene textiles. The most common procedure for the modification of polypropylene fibres involves adding additives in the form of masterbaches, which are incorporated into polymer by physical means duri...

The work is devoted to developing the optimal design for granulation equipment aimed to modify ordinary ammonium nitrate with the subsequent obtaining of nanoporous structure. We present the fundamental technological calculation of vortex-type granulation equipment with various configurations of a vortex fluidized bed (including a combined one). We...

Current paper is devoted to the description of the algorithm for obtaining porous ammonium nitrate granules in granulation units using devices with different configurations of the fluidized bed. We present brief theoretical background for calculation of the granulation plant main equipment. We propose the design of individual units for sequential i...

Hlavním cílem tohoto článku je provést analýzu metod předzpracování obrazu a uvést jednotlivé autory a publikace, které se jimi zabývají. Za účelem získání systematického přehledu je v článku navržena metodika pro vyhledávání jednotlivých relevantních zdrojů. Metody předzpracování obrazu předcházejí automatické detekci účastníků silničního provozu....

Composite materials have a wide range of functional properties, which is ensured by using various technological methods of obtaining both the matrix or fillers and the composition as a whole. A special place belongs to the composition formation technology, which ensures the necessary structure and properties of the composite. In this work, a comput...

This work is devoted to describing the technological foundations and the main stages of calculating granulation machines with active hydrodynamic modes. The optimisation criterion is substantiated when choosing the design of the granulation machine. The work uses methods of analysis and synthesis, search for cause-and-effect relationships, theoreti...

Current paper substantiates the possibility of obtaining porous ammonium nitrate (PAN) granules in apparatuses with intensive hydrodynamics and directional movement of the fluidized bed of granules. We developed a theoretical model for calculating the hydrodynamic performance of vortex granulators allowing to conduct experimental studies of the nan...

The current paper describes the technological foundations of the porous ammonium nitrate (PAN) convective drying stage in a multistage shelf unit operating as part of a small-sized granulation module. The work consists of two blocks: the theoretical foundations of a multistage shelf dryer operation and the study of the nanoporous PAN structure in t...

Current paper is devoted to the study of formation process of a nanoporous structure in porous ammonium nitrate granules during their humidification and heat treatment in vortex devices. We briefly present the main methods for porous ammonium nitrate granules formation. We demonstrate that it is necessary to control the process of nanoporous struct...

The application of different structural materials to manufacture basic parts of drying units of various types was analyzed. It has been established that surface erosion of materials resulting from solid par-ticles' impact is a serious problem for many industrial equipment types using multiphase flow. It is shown that the value of the erosion rate d...

The article is devoted to the development of the technological principlesregarding thefinal drying process of the porous ammonium nitrate (PAN) granules in multistage gravitational shelf dryers. The data on the dryer’s optimal technological operatingmodes are obtained. PAN samples are studied; the regularity of the change in the porous structure of...

The article deals with the study of main hydrodynamic characteristics of the directed fluidized bed in gravitation shelf dryers. The algorithm to calculate hydrodynamic characteristics of the directed fluidized bed in the dryer’s workspace is described. Every block of algorithm has theoretical model of calculation. Principles of disperse phase moti...

The article describes the prospects for experimental research of liquid-vapor jet devices with adaptable geometry of the flow part of the primary flow nozzle. To formulate the research objectives, a critical analysis of state-of-the-art studies was conducted among native and foreign scientists studying two-phase jet devices. As a result, of the lit...

The current paper aims to find scientifically valid approaches to improving the environmental safety of technologies for drying grain materials and granular fertilizers. The methodology for environmental and economic efficiency justification of the energy-saving multi-stage shelf dryers with a convective fluidized bed drying provides design and ope...

The technical and economic efficiency of new PCMs depends on the ability to predict their performance. The problem of predicting the properties of PCMs can be solved by computer simulation by the finite element method. In this work, an experimental determination of the physical and mechanical properties of PTFE PCMs depending on the concentration o...

This article is devoted to modeling, researching and optimizing the main properties of an environmentally clean polymer composition based on oligofurfuryloxysiloxanes (OFOS), which can be used to produce casting molds and cores in the production of castings from ferrous and nonferrous metals. Polymer compositions were examined for strength, surviva...

The textile materials can be used in many technical applications in various fields, such as automotive. Depending on the application areas, the textile or fiber‐based materials have to meet certain predetermined requirements. Textile yarns can be used as reinforcing cords in composites in which an elastomeric matrix is used. The basic mechanical te...

In this study, a new generalized regression neural network model for predicting the curing characteristics of rubber blends with different contents of carbon black filler cured at various temperatures is proposed for the first time The carbon black contents in the rubber blend and cure temperature were used as input parameters, while the minimum an...

selected pages

The article studies the final drying stage in the porous ammonium nitrate (PAN) production. Based on the analysis of the ammonium nitrate, authors propose to improve the scheme for the PAN production by introducing the final drying stage after humidification and heat treatment of PAN in a vortex granulator. The analysis of literature proposes a new...

Authors: Nadiia Artyukhova, ORCID: https://orcid.org/0000-0002-2408-5737 PhD, Associated Professor, Sumy State University, Ukraine Jan Krmela, ORCID: https://orcid.org/0000-0001-9767-9870 PhD, Associated Professor, University of Pardubice, Czech Republic Vladimira Krmelova, ORCID: https://orcid.org/0000-0002-3822-3416 PhD, Associated Professor, Ale...

The present monograph deals with specific testing of polymer composites and polymer textile cords, which are used as reinforcement for the composites. Textile cord-rubber composites were selected for the research. The basic mechanical tensile test at standard temperature does not provide all the information required for obtaining the material param...

This paper is a literature review about tire component requirements for innovation in tire construction. Herein are pointed out essential aspects expected in Tires’ structures from the mechanical point of view for future development of a realistic model for advanced simulation of tires (in miscellaneous operating conditions) and innovation in tire...

This paper deals with the creation of a computational model of a multi-layered composite made of long fibres embedded in a polymer matrix and its use to simulate the response of the composite to a shear test. The research involves the determination of material parameters of the matrix (elastomer, in the context of the current paper) as well as of f...

The article is devoted to the study of multistage dryers with vertical sectioning of the working space. The factors of influence of the design of the shelf contact and the consumption of the drying agent on the mode of movement of monodisperse and polydisperse material are analyzed. The achievement of the required hydrodynamic regime (at a constant...

The main objective of this work was to investigate the effect of different cellulose (CEL) content and the draw ratio on the thermal and mechanical properties of drawn polypropylene (PP) fibres. The modification of PP fibres during their production can helps to prepare PP fibres with improved properties, guarantees new opportunities for the expansi...

This work was focused on studying the properties of epoxy (EP) composite materials reinforced with glass, (GF) carbon (CF) and aramid (AF) fibres. The composites were made by hand lay-up (HL) and vacuum infusion process (VIP) with 8, 10, 12 number of fabric layers. Studied were tensile strength, elongation, flexural stress, flexural strain, thermal...

The chapter describes the theoretical fundamentals for the final drying of ammonium nitrate granules with the nanoporous structure in multistage shelf units. The computer modeling of the hydrodynamic conditions for the final drying of porous ammonium nitrate (PAN) is demonstrated. The moisture content changing process in the disperse material and a...

This work substantiates the possibility to control the quality of nanostructured porous layers in porous ammonium nitrate (PAN) granules by introducing an additional stage of final drying and choosing the optimal thermodynamic conditions for this process. The necessity of the final drying stage in the PAN production technology is validated. An algo...

This paper has substantiated the expediency and prospects of obtaining organomineral fertilizers by encapsulating mineral granules with an organic suspension in fluidized bed apparatuses. An overview of existing approaches to the mathematical description of the kinetics of granule growth in granulation processes in fluidized bed apparatuses is pres...

Soubor uložte do svého PC a otevřte prostřednictvím Acrobat Reader. Soubor pdf obsahuje přílohy xls, doc, dwg a sldprt. Skriptum bylo vytvořeno pro předměty Konstrukce silničních vozidel I a II. jako studijní materiál pro studenty a jsou orientována na vybrané výpočty podvozkové části automobilů, mezi které patří výpočty spojky, převodovky, vinuté...

The article describes a new technology for the formation of nanoporous layers on the ammonium nitrate granule as a component of an industrial explosive. The main methods of porous ammonium nitrate (PAN) production are defined. The authors substantiate the effective implementation of the combined method of humidification and heat treatment. It is pr...

This textbook consists of two different but related parts. The first part „Ergonomics modify conditions of work“ is based on various authors and publications and other sources have been used (see References at pages 12-14). This part was compiled so that the problem of ergonomics was described more comprehensively. The second part „The safety at...

High-strength screws represent one of the main joining or fastening components which are commonly used in the process of installation of frame constructions for information boards or signposts, relating to the traffic roads. The control of the production process may not always be a sufficient method for ensuring road safety. The backward investigat...

The design features of diaphragm compressors are discussed in this article. For preventing the formation of local stresses in certain areas of the diaphragm, it is recommended to use thin sheet stainless steel of the transition class. A comparative analysis is made of two batches of steel tape, differing in the value of the saturation magnetic indu...

This article deals with the possibilities of adhesion force changes of a road vehicle. The authors present the possibilities of reducing the adhesion force of road vehicles and,at the same time,present their own system for changing the radial reaction of the vehicle wheels. This system removes the disadvantages of a commercially available SkidCar s...

1. Tire Introduction (17) / 2. Tire Tests (48) / 3. Outputs from Experiments (84) / 4. Experiments of Tire Parts (157) / 5. Degradation Processes (200) / 6. Computational Modelling of Tire (236) / 7. Creation of Computational Models (266) / 8. Outputs from Simulations (287) / 9. Interest Information (315) / 10. Conclusion (357).

Citation: Yukhymenko, M.; Artyukhov, A.; Ostroha, R.; Artyukhova, N.; Krmela, J.; Bocko, J.The article deals with the theoretical description and experimental study of the hydrodynamic and heat transfer properties regarding the operation of multistage gravitational devices of the fluidized bed with inclined perforated shelves. The peculiarities of...

The article deals with the study on the efficiency of units for porous ammonium nitrate production. The ways which increase the effective implementation of energy resources are determined by including the ejector recycling module, heat and mass exchangers that utilize principles of regenerative indirect evaporative cooling, and the sub-atmospheric...

The work is devoted to the creation of a thermodynamic optimization method for calculating a vortex granulator. An algorithm to determine the temperature fields in the workspace of a vortex granulator is based on the previous data; a series of thermal imaging studies and the results of computer modeling is proposed. The results of studies regarding...

The article deals with determination of material parameters of elastomer (rubber) for computational modeling based on experiment data - hardness and also determination of materials parameters of specific composite materials for next-generation tires. Mooney-Rivlin parameters of elastomers can be determined on the basis of the Shore A hardness. Ther...

The article is devoted to finding ways to assess the quality of educational activities at the university through analogies between tangible (technical) and intangible systems. The approach to determining the level of technological readiness for implementation (TRL) was used as a tool to assess the level of development of the quality of education sy...

The article analyzes the relationship between the concepts “quality of scientific activity”, “technology transfer” and “research integrity”. The main task of research is to offer practical tools for maintaining research integrity as elements of the internal and external quality assurance system of education and research. One of the working hypothes...

This paper summarizes the arguments and counterarguments within the scientific discussion on the issue open science in health economics in the reality of the Covid-19 pandemic. The aim is to study the openness of the results of scientific work in the field of health economics. To achieve this goal, the following tasks have been set: to conduct a bi...

Modelling the influence of high-energy ionising radiation on the properties of materials with polymeric matrix using advanced artificial intelligence tools plays an important role in the research and development of new materials for various industrial applications. It also applies to effective modification of existing materials based on polymer mat...

The article describes the technological basis for production of the ammonium nitrate with a nanoporous structure as a component of the non-trotyl industrial explosive ANFO. The necessity to obtain a nanoporous structure with various pores to ensure reliable absorptivity and retentivity of diesel fuel distillate is substantiated. The construction of...

The chapter is devoted to the study of the ammonium nitrate granules structure with nanostructured porous layers, which are obtained as a result of moistening and multistage drying. The necessity of an additional stage of granule dehydration in the technology of porous ammonium nitrate producing has substantiated. Basic constructions of the updated...

The paper presents the results of an experimental research and a numerical calculation of a multi-gap seal of a centrifugal pump. The experimental research allowed to obtain the characteristics' performance of the multi-gap seal at different operating modes, in dependence on the axial size of the chambers, pressure distributions' changes, and a lea...

The main advantages regarding the convective drying of the granular materials in the multistage dryers with sloping perforated shelves were represented. Peculiarities of the shelf dryers’ hydrodynamics were shown in the research. Various hydrodynamic weighing modes were experimentally justified, and the relevant criteria equations were obtained. Th...

The article deals with author’s software products review to calculate devices with highly turbulized flows as a part of granulation units. Principal scheme and model of the granulation unit, algorithm of the granulation technical calculation are represented in the work. The complex automated calculation technique of the granulation units is propose...