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The main parameters of the hot forming machines are production capacity and the fatigue life of the used tools. The life of a tool depends on its shape and load. The load depends on the structural design and speed of forming. The goal of our paper is to present the structural optimization and technological parameters design with respect to tool life. This process is applied in the case of the hot forming machine analysis.

The thermodynamic derivatives based on fundamentals thermodynamic space and physical parameters of natural gas influences other variables of pipeline systems such as pressure, temperature, velocity, density, gas compressibility, etc. These variables are crucial for gas pipeline system knowledge and its accurate operation. Fundamental parameters are derived such as Joule-Thomson (J-T) coefficient, isothermal throttling coefficient and isentropic coefficient. They influence gas flow when during the expansion of natural gas in the pipeline, the gas cools down due to the J-T effect and due to the interaction between pipeline system and its surroundings to the conditions at which gas is saturated by water vapour (dew point), and gas is not able to keep excess humidity and its condensation and gas hydrate formation will occur. The article deals with analyses of selected thermodynamic derivatives in the range of chosen temperatures and pressures and also non-isothermal steady-state flow model for pipeline is presented.

For the creation of the bond the treatment of the adhesive bonded surface is essential. The second important factor is the temperature of the environment to which the adhesive bond is exposed. It is a way of a degradation of adhesive bonds. The aim of the research was to evaluate the effect of adhesive bonded surface treatment of alloy AlCu4Mg and increased environmental temperature on a strength of adhesive bonds using two-component epoxies used in the transportation industry. As a bonding material AlCu4Mg was used, whose surface was in the first series mechanically and chemically treated. In the second series tested specimens were without the surface treatment. A destructive testing was conducted at a laboratory temperature 22 ± 2 °C and at increased temperatures, i.e. 40, 60 and 80 ± 2 °C. At a mutual comparison of the mechanical treatment and the chemical treatment of the adhesive bonded surface with un-treated surface, the tensile lap-shear strength increased by an average of 57.24 ± 18.52 %. The results show that there is a difference in the tensile lap-shear strength between the test temperatures in the interval 20-80 °C, the decrease was up to 88 %.

Aluminium and silicon alloys are widely used in practice currently, e.g. in car industry, aircraft industry or in civil engineering. Hence there is increasingly more emphasis placed on research and development of silumins. The aim of this paper is to analyse aluminium alloy, namely the alloy AlSi7Mg0.3. This paper is focused on the effect of particular modifiers and heat treatment on the selected properties of the alloy, especially on structural transformations caused by various modifiers, hardness measurement (Brinell method) and microhardness testing (Vickers method). Four variants of castings (unmodified alloy and alloy modified by chemical elements - strontium, calcium and antimony) were tested. All alloys were compared to the cast of pure aluminium (Al 99.8%). There were moulded four castings from each variant and two castings of pure aluminium. It was casted using a gravity-die casting into a metal mold with a thermal insulation - except of pure aluminium (without thermal insulation).

Aluminium is widely represented material in engineering - one of the possible forms of application is an Al powder, when mutual interaction mainly with polymer matrix creates new materials. In practice, the aluminium powder is commonly used together with a number of reaction resins, e.g. epoxy resins. Such systems can be described as liquid metals, and amongst other options of the application, they are used for quick renovation of the functional areas of machines. In such applications, particularly important are hardness and durability of the composite layer against wear. This paper experimentally evaluate the friction and wear of systems based on epoxy resin with aluminium powder (microparticles), through reciprocating sliding tribotests. Tribological outcomes evidenced a reduction of the friction coefficient when the resin is reinforced by alumium particles, with a concentration of 32% in term of volume fraction.

Usually, the coatings used in industrial applications require post-processing to reach their final shape. However, some of these coatings are difficult-to-cut, mainly because of their high hardness. The present study provides a revision of some experimental investigations on the turning of WC-Co, Stellite, and Fe-based and NiAl alloys. The materials are used for both coatings and sintered workpieces providing insights for conducting turning tests. For the success of the turning process, the selection of the machining parameters is a critical issue. Based on the reviewed investigations, the surface roughness is clearly influenced by the feed rate, expecting higher values than the ones predicted by the theoretical equations. Besides, the increase of both the cutting speed and feed rate leads to a high tool wear. Likewise, the increase of the feed rate leads to higher machining forces. In general, the influence of the cutting speed and depth of cut is less evident. Regarding the machining parameters, usually their maximum values are fixed at low levels: 100 m/min, 0.35 mm/rev and 0.3 mm, for the cutting speed, feed rate and depth of cut, respectively.

A constructional shape of an adhesive bond deals with a mutual position of bonded parts in such way to gain a given contact area. The constructional shape of the adhesive bond finds a practical application at connecting of plain areas that means sheets of metal above all. The adhesive bond strength at connecting the galvanized sheet of metal was significantly lower than at connecting a constructional carbon steel. Results of specimens of wavy-lap bonds showed higher values of the adhesive bond strength comparing with specimens of single-lap bonds. The wavy-lap constructional adjustment proved to be positive at connecting the galvanized sheet of metal. The increase of the adhesive bond strength ranged in the interval 27 to 560 %. The difference in using specimens A (single-lap bond) and B (wavy-lap bond) is obvious from the statistical comparison. It is visible from performed experiment that using the specimen B (wavy-lap bond) led to increasing of strength values of the adhesive bond.

Detection system of infrared thermography technology was designed, taking a non-refrigeration focal plane infrared camera and the pulse flash heating system with high energy as the core. Combining with the performance parameters and structure features of the hardware equipment, integrated control system was designed. Meantime, the cover and reflector for the detection system were fabricated, which improved the uniformity and the utilization rate of energy for the thermal excitation source of the flash lamp. Based on the Delphi program, control, acquisition, processing and analysis system for the infrared image sequence were developed. And defect identification software was also researched which could implement the quantitative calculation and analysis for the parameters of defect size, location, perimeter, area and depth. Finally, experiments for metal and composite with flat bottom defects were carried out by the use of the detection system proposed in this study. The results show that the detection system has the advantages of well controllable performance, convenient operation, perfect detection effect, powerful image processing functions, which can meet the testing demand for engineering application.

Nowadays people spend still more of their life on the road. Vehicles has been becoming increasingly sophisticated and the main direction of their development is placed primarily into the areas of environment, design, safety and comfort. This work focuses primarily on the last-mentioned point, and that's seating comfort and the phenomena with straight influence on the transported persons. Probably with any of car elements, isn't the person in a direct contact to much as with the seat and therefore the seats and their innovation are still in considerable interest of the customers and manufacturers. This work deals with description of the resulting tensions and distribution of the specific pressures in the cushion of a car seat and also describe the creation of an appropriate computational model.
Based on the real transmission data, that was measured during driving a car, has been carried out an experimental measurements of static and dynamic loading of the overall stiffness and response of the system. Subsequently, depending to the real CAD data were compiled the boundary and materials conditions that describe the statical FEM model of the polyurethane cushion. For the quasi static load was carried out the experimental measurements on a mechanical pulsator, that is suitable for assessing the viscoelastic and hysteresis effects inside the materials. The found results have been verified with using the x-sensor on a model of real human back during the scanning of its specific contact pressure.

The main aim of this experimental paper is investigation, analyzing and realizing the experimental measurement of cutting temperature when external turning of rotational parts made from AlCu3MgMnPb aluminum alloy. In this experimental study a number of turning tests have been carried out by using a test lathe and a cutting temperature measuring device. This measurement have been successively investigated and experimentally verified with the special samples (in experimental measuring of the temperature during the turning process of samples and measured results designated with special thermal camcorder type FLIR used for special measurement of cutting temperature). The theoretical contribution of the realized experiment is the finding that the change of cutting speed, depth of cut, feed motion and cutting temperature increase with increasing of the chip emerging influence factors change over time. Practical benefit is recognition that the emerging shape of the chips in turning of aluminum alloy is a consequence of the deformation process, which depends on the measured sample from its crystal structure and the conditions under which the deformation process occurs mainly by the deformation, cutting speed and temperature.

Lead is traditionally used for completing free-machining materials. This paper deals with newly developed lead free copper alloys. Unfortunately, lead affects the haematological and nervous system. Therefore, materials containing lead represent one of the greatest environmental problems in world production. Research Material Institute in Panenske Brezany (CZ) developed new environmentally friendly cooper alloys. Machinability of these materials was tested at the Department of Machining, Process Planning and Metrology CTU in Prague. Some of the research results related to the machinability from the viewpoint of chip forms, surface roughness, cutting temperature, cutting time in drilling with constant feed force, and forces in cutting are presented.

The paper presents results of experimental investigation of steady flow in the region of common carotid artery (CCA). The CCA bifurcates into two branches: into internal carotid artery (ICA) and external carotid artery (ECA). ICA, that supplies blood to the brain is enlarged. This region is referred as the carotid sinus. In the present study, three models of the carotid artery bifurcation have been manufactured. The models vary in geometry of the carotid sinus. Their effect on fluid flow has been investigated under steady flow condition, utilizing Particle Image Velocimetry (PIV) and flow visualization. The flow conditions approximate physiological flow. The measuring range of Reynolds number was from 400 to 1300. Experimental results indicated the effect of carotid sinus geometry on the main flow in common carotid artery.

In most cases, construction materials are selected so as to attain the optimal technological properties at the lowest possible weight and cost. Studies on the improvement of the properties of casting alloys have been continuously conducted over the recent years. Both the microstructure and properties of alloys may be altered via modification with chemical components, optimization of the crystallization process, heat treatment or a combination of these methods. While searching for alternative methods of improving the engineering surface properties of hypo- and hypereutectic Al-Si alloy, an attempt was made to modify its microstructure with the use one of a heat sources. This paper presents the results of an experiment investigating the microstructure and the hardness of the Al-9%SiMg and Al-20%SiMg alloys processed by TIG welding method.

The structural entirety of any biomaterial has to be tested to inhibit to untimely failure and thus maintaining the reliability of the replacement. The knowledge of dielectric properties (relative permittivity, loss factor) of biomaterial without defects in defined microwave frequency range (8-12 GHz) and subsequently comparing properties in defective material as changes in material and classifying the occurrence of inhomogeneities as on the surface so inside the structure. This article deals with possibility to create dental phantom with the same properties as used in practice and dielectric properties measurement method (Hippel method). We made phantom from poly methyl methacrylate (PMMA). PMMA is very commonly used dental material as crown of human tooth or as the crown for intra-osseous dental implantant.

The contribution deals with the study of magnetic structures, computational methods used in analyzing the interaction of magnetic fields with application this knowledge in practice.
The main object of study is design of blocking element of magnetic cycloid gearbox. This paper describes the design methodology of magnetic blocking element, calculation of the braking system, the maximum breakaway torque at slipping in magnetic coupling and power ratios during this action.

Cutting fluids are complex mixtures used to cool, lubricate and remove metal chips from tools and metal parts during grinding, cutting, or boring operations. Utilization of cutting fluids in the technological process of metalworking often generates aerosols which represent a significant hazard to the safety of workers and to the environment. The paper deals with the research of cutting fluid's impact on aerosol production by expressing particle size distribution. We used a special image analysis algorithm for the data obtained by a high-speed camera to determine the particle size. The procedure of result assessment was created for measuring the size of small droplets and it was implemented in a MATLAB application. Multifactor analysis of variance (ANOVA) and nonparametric analysis of variance were used for statistical result evaluation.

The paper is devoted to the mechanical system dynamic properties investigation of the test stand RAILBCOT (RAIL vehicles Brake Components Test stand). Using sensors attached to some parts, have been measured values of positions, the longitudinal, vertical and transversal forces, revolutions and accelerations. There was created computational model of the mechanical system in SIMPACK software system environment. There were performed model establishment, starting and boundary condition setting and simulation computations to determine the dynamic properties parameters. The measured values were compared with calculated values. Subsequent verification has been confirmed the necessity of modification of the flexible member of the bench. The paper consists of issue definition and the comprehensive references specification from the field of investigation of working team at the University of Žilina relevant to this field of study.

The Mg-5.6Gd-0.6Y-0.4Nd-0.2Zn-0.2Zr (wt. %) alloy was prepared by metal mold casting. Then the alloy was subjected to hot forging. The microstructure and mechanical properties of the solution-treated, hot-forged and aged alloy samples were studied. The affects of deformation processes on the microstructure and mechanical properties were discussed, and the strengthening mechanisms of alloy were also investigated. The results revealed that the coarse second phases distribute along the dendrite boundaries in the solution-treated alloy. After hot forging, the second phases were broken into small particles and the grains get uniformity. Tensile test results showed that the strength of alloy was greatly improved after hot deformation processes. The forged alloy showed remarkable age hardening response at aging temperature of 180°C. The peak hardness was obtained by the time of 72h. The ultimate tensile strength and yield strength of the peak-aged alloy were 275MPa, 181MPa at room temperature, and 209MPa, 127MPa at 300°C, respectively. The high mechanical properties were mainly attributed to the fine microstructure and fine dispersed metastable precipitates in the matrix.

Intermetallics offer many interesting properties, such as excellent resistance against high-temperature oxidation and creep, special magnetic properties, shape memory or the ability of reversible hydrogen storage. For these reasons, intermetallics are considered as very promising materials for many modern applications in power generation, automotive or aerospace industry and also in the medicine. The factors limiting their wider use are low room-temperature toughness and problems with their production. In this work, the possibilities of the use of powder metallurgy using reactive sintering for the production of intermetallics for medicine (Ni-Ti alloys) and for high-temperature applications (aluminides, silicides) are presented. The effect of process parameters on the proceeding reactions and structure of obtained materials is discussed.

Hydroxiapatite is ceramic material with properties and composition similar to the bone tissue. This makes it a suitable choice for biomaterials. However, hydroxyapatite alone has poor mechanical properties. Present paper shows two possible applications of hydroxyapatite in materials intended for medical applications. 1. Hydroxyapatite can be used as a layer which causes the material to be more bioactive. In this article the layer of HA is applied on WE43 by plasma spraying and structure, composition and adhesive properties are measured. 2. Hydroxyapatite can serve as reinforcement in metallic composite materials. Present work sum up properties of composite materials with 2, 5 and 10 wt.% of HA that were prepared by powder metallurgy route. The structure, hardness and compressive mechanical properties are characterized.

Paper deals with comparasion of methods for resolving stress state on the example of forged crane hook of selected load. For suitability of the comparasion is necessary to achieve comparable stress values by different methods. Problem of solving of different assignments by different methods is very extensive, and because of it, there is not clear answer, which of methods is universal and so always optimal. Any factors, that enter to the calculation and influence it, is the best way to choose an optimal method for solving of strength problems in mechanics.

The key topic of this article is a study of the oil flow and pressure distribution on the surface gearing investigated using numerical simulations. Particularly, this paper is focused on a simulation of the single flow of oil, which is governed by the gearing motion. Results of the unsteady flow between two rotating gearing could help to identify reasons of damages of gearings. The destruction of surface is identified after several hours on the helical gearing which is used in a heavy industry. In the case of moving and rotating gearing, it was necessary to use dynamic mesh and procedure of remeshing based on the parameters of quality cells. The simulation provides the complete information of pressure distribution on the surface of gearings. By the analysis of numerical results the areas with the high frequencies of low pressure were identified.

The article deals with the dynamic analysis of long freight wagon with a low and multifunctional loading plane for intermodal transport. The main task of simulation was to verify enough overlap of buffers, when the vehicle rides through S-curve, because the wagon is equipped with non-standard construction of the front part of undercarriage. Simulation was performed in program Adams, module VI-Rail. These and similar analyzes are nowadays an integral part of the development process of rolling stock and greatly reduce the time necessary for design, tests and certification of new vehicles. In the future, it will be possible in the case of verification results replace some real tests by simulation analysis on certain conditions.

Aluminium, chromium, silver and other metal targets are often used for glass crystal coating in jewellery. The structure of targets strongly influences the quality of coating which leads to differences in their optical properties. The targets from two manufacturers were examined using scanning electron microscopy combined with EBSD with a goal to identify possible metallographic cause of defects arising on glass jewels.

Modification alloy is an important part of the metallurgical process, and this also applies, of course, for aluminum alloys, particularly for Al-Si (silumins). As a modification of the material we can use the modification using the selected element or heat treatment of alloys, or a combination of both processes. One of the elements that it is possible to modify the alloy of Al-Si used is antimony (Sb). The paper examines the possible effect of the modification that element and heat treatment on the final structure of the alloy AlSi9CuMnNi. In the experiments were made three castings from the alloy AlSi9CuMnNi without modification, three castings with the modification and without heat treatment, three castings with modification and without heat treatment, and three castings with modification and heat treatment too. The described experiment and analysis are part of extensive research, focusing on a Faculty of Production Technology and Management, J. E. Purkyne University in Usti nad Labem.

The article is aimed on present research of internal friction mechanisms that are responsible for the temperature behaviour of AZ91 magnesium alloys. These mechanisms have been studied by ultrasonic resonant apparatus at a frequency close to 20470 Hz and in a temperature range from 50 °C up to 400 °C. The specimen on internal friction measurement has an hour glass shape. The specimens were in the as cast state and after measurement showed dendritic structure. Structure of magnesium alloys AZ91 was carried out after the homogenization annealing at temperature 390 °C. It was also used application of mathematical calculations for a more accurately experimental measurement of internal friction depending on the temperature.

Metal-plastic parts with steel inserts prepared by overmolding technique showed several cracks. Cracks marked as no 1 and 2 were noticed immediately after overmoulding process. Cracks no 3 and 4 were propagated only several days after overmolding, during post crystallization of plastic. The superposition of both high residual stresses at the metal-plastic interface and creation of cold joints in overmolding plastic were the reasons of cracks initiations. Residual stresses at the metal-plastic interface exceeding the yield strength of plastic were confirmed by simulation in Moldflow software. The differences in the melt front temperature above 20 °C were simulated in the critical areas where the cold joints created in the real metal-plastic parts. Cracks no 1, 2 and 3 were eliminated by increasing of plastic thickness in the critical areas. Cracks no 4 were eliminated by decreasing of packing pressure, what also contributed to the elimination of cracks no 3.

The purpose of this paper is to describe the area of risk management, in which maintenance can positively contribute to risk reduction and suggested reliability methods and maintenance tools can be used for risk treatment. The authors define the relationship between critical failure and risk and influence of preventive maintenance and redundancy on risk level. The risk level is defined as a product of critical failure probability and cost of critical failure losses. The proposed method enables to quantify risk treatment results. Benefits of the proposed risk treatment method based on preventive maintenance and redundancy applications are risk reduction and decreased costs (losses) of critical failure consequences within chemistry and nuclear power industrial technology. All decisions of maintenance have to be assessed according to economic criteria for specific objects and conditions in order to choose proper system maintenance.

An adhesive bonding technology is a method of a connecting which is used at a construction of coach-works, agricultural machines etc. This method is suitable for workings with a serial production. Many research projects dealt with a preparation of adhesive bonds, degradation aspects etc. An area, which has not been properly investigated at present, is an influence of a loading speed on strength of the adhesive bond and a destruction time of the adhesive bond. Adhesive bonds are loaded by a different intensity and a speed at a practice.
The research focused on an evaluation of the influence of the loading speed at a temperature 22 ± 2 °C on the shear tensile strength, the time needed for the destruction and a failure area. Second part of the research was focused on the influence of a bending moment. This bending moment can be minimalized by using so-called underlaying sheet of metal. The underlaying sheet of metal was of a thickness corresponding to a thickness of the adhesive bonded material. Also a behaviour of the adhesive bonded material was observed within the research.

Aluminium bronzes can find use in many engineering applications thanks to their excellent properties, predominantly high corrosion resistance, good ultimate tensile strength, fatigue strength and creep strength. Yet, their mechanical properties can still be improved, most importantly by appropriate heat treatment. The type of heat treatment is typically chosen with regard to the desired properties of the product and its service conditions. This paper attempts to summarise the microstructural changes which take place in aluminium bronzes during heat treatment. Another objective of this study was to map the potential of a certain type of aluminium bronzes for undergoing martensitic transformation. The methods, which were chosen for assessing the results of heat treatment with regard to their availability, included measurement of hardness and observation of microstructure using light and scanning electron microscopy, Additional tools for evaluation of microstructure comprised measurement of microhardness and chemical analysis by EDS.