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Open access

Vitalii A. Smirnov and Aleksandr V. Repko

Abstract

The paper presents the results of researches of temperature variations during flat peripheral grinding. It is shown that the temperature variations of the workpiece can reach 25...30% of the average values, which can lead to some thermal defects. A nonlinear two-dimensional thermophysical grinding model is suggested. It takes into account local changes in the cutting conditions: the fluctuation of the cut layer and the cutting force, the thermal impact of the cutting grains, and the presence of surface cavities in the intermittent wheel. For the numerical solution of the problem, the method of finite differences is adapted. Researches of the method stability and convergence are made, taking into account the specific nature of the problem. A high accuracy of the approximation of the boundary conditions and the nonlinear heat equation is provided. An experimental verification of the proposed thermophysical model was carried out with the use of installation for simultaneous measurement of the grinding force and temperature. It is shown that the discrepancy between the theoretical and experimental values of the grinding temperature does not exceed 5%. The proposed thermophysical model makes it possible to predict with high accuracy the temperature variations during grinding by the wheel periphery.

Open access

Nikodem Wróbel, Michał Rejek and Grzegorz Królczyk

Abstract

The purpose of this study is to form and test inseparable tight joints, commonly used in the construction of heat exchangers, by crimping operation on designed prototype stand. Crimped joints are made by tools in form of cones with two types of shapes, each of the designed tools have got identical forming angle. This study uses two types of connecting blocks and plates, differing in diameters of hole and flange. Elaboration contains a case study of joints being made by the stand, which in addition to the crimping operations for some cases were glued or brazed. The article presents the features of the formed joints, by examining them by destructive testing: Micrography, tensile strength test, and non-destructive testing: Leakage test. The examined elements have been made of aluminum 6060, which is well suited to indirect or direct operations of forming joints for all kinds of coolers or condensers. Elaborated tests and studies in this study allowed to state, that joining the connection block to plate with the small diameter, was more energy-consuming than in sample sets with bigger diameter, use of glue increasing the strength of the joints by 20%, significant strength increase can be obtained after mechanical clinching with brazing operation or modification of geometrical shape of the jaws

Open access

Dorota Chybowska, Leszek Chybowski and Valeri Souchkov

Abstract

Poland has a strong ambition to evolve rapidly into a knowledge-driven economy. Since 2004, it has been the largest beneficiary of European Union cohesion policy funds among all member states. Between 2007 and 2013, Poland was allocated approximately EUR 67 billion, whereas for 2014-2020 the EU budget earmarked EUR 82.5 billion for Polish cohesion policy. This means that in the coming years, Poland’s R&D intensity will grow. But the question remains: is 27 years of free market economy enough to enable a country’s economy to become knowledge-based ? This paper offers an analysis of Polish R&D expenditures and investments in terms of their sources (business, government or higher education sectors), types (European Union or state aid) and areas of support (infrastructure, education or innovation). It also characterises the Polish R&D market with its strengths and weaknesses. Then, it examines the process of technology transfer in Poland, comparing it to best practice. Finally, the paper lays out the barriers to effective commercialisation that need to be overcome, and attempts to answer the question raised in its title.

Open access

Michał Stawowiak and Mariusz Kuczaj

Abstract

This article refers to the reliability of road rollers used in a selected roadworks company. Information on the method of road rollers service and how the service affects the reliability of these rollers is presented. Attention was paid to the process of the implemented maintenance plan with regard to the machine's operational time. The reliability of road rollers was analyzed by determining and interpreting readiness coefficients.

Open access

Erika Sujová and Helena Čierna

Abstract

The paper deals with increasing processes efficiency at a production line of cylinder heads of engines in a production company operating in the automotive industry. The goal is to achieve improvement and optimization of test processes on a production line. It analyzes options for improving capacity, availability and productivity of processes of an output test by using modern technology available on the market. We have focused on analysis of operation times before and after optimization of test processes at specific production sections. By analyzing measured results we have determined differences in time before and after improvement of the process. We have determined a coefficient of efficiency OEE and by comparing outputs we have confirmed real improvement of the process of the output test of cylinder heads.

Open access

Frederik Stefanski and Bartosz Minorowicz

Abstract

This paper is focused on the open loop control of a piezoelectric tube actuator, hindered by a strong hysteresis. The actuator was distinguished with 22 % hysteresis, which hinders the positioning of piezoelectric actuator. One of the possible ways to solve this problem is application of an accurate analytical inversed model of the hysteresis in the control loop. In this paper generalized Prandtl-Ishlinskii model was used for both modeling and open loop control of the piezoelectric actuator. Achieved modeling error does not exceed max. 2.34 % of the whole range of tube deflection. Finally, the inverse hysteresis model was applied to the control line of the tube. For the same input signal (damped sine 0.2 Hz) as for the model estimation the positioning error was max. 4.6 % of the tube deflection. Additionally, for a verification reason three different complex harmonic functions were applied. For the verification functions, still a good positioning was obtained with positioning error of max.4.56 %, 6.75 %and5.6%of the tube deflection.

Open access

Konrad Łyduch and Wojciech Gęstwa

Abstract

The paper presents the influences of nanofluids, which are used in hardening process, to dimension changes, hardness and microstructure of hardened construction of steel samples. An analysis was also carried out with the use of English methods of cooling abilities of nanofluids environments based on water, solid nanoparticles of Al2O3 and ammoniac water. The results of this experiment show, that only one of specific dimensions of cooled samples, in the distilled water, changed for about 9%, but when using nanofluids this change was smaller. The hardness of alloy materials got a few percent more when nanofluids were used in comparasion to using the distilled water. The gained results allow to conclude the positive influence of nanofluids on parameters of the hardened materials.

Open access

Augustyn Lorenc and Krzysztof Przyłuski

Abstract

The aim of the paper was to improve service processes carried out by Knorr-Bremse Systemy Kolejowe Polska sp. z o.o. Particularly, emphasise unnecessary movements and physical efforts of employees. The indirect goal was to find a solution in the simplest possible way using the Muda ideology. In order to improve the service process at the beginning was executed the process mapping for the devices to be repaired, ie. brake callipers, electro-hydraulic units and auxiliary release units. The processes were assessed and shown as Pareto-Lorenz analysis. In order to determine the most time consuming process. Based on the obtained results use of a column crane with articulated arm was proposed to facilitate the transfer of heavy components between areas. The final step was to assess the effectiveness of the proposed solution in terms of time saving. From the company perspective results of the analysis are important. The proposed solution not only reduces total service time but also contributes to crew’s work comfort.

Open access

Michalene Eva Grebski and Radosław Wolniak

Abstract

Paper addresses the different methods for protecting intellectual property in modern knowledge-based economies. The focus of the paper is a comparison between the procedures for applying for patents in Poland and the United States. The comparison has been made from the perspective of the cost of obtaining and maintaining a patent in Poland, the United States and some other countries. The comparison has also been made from the perspective of the procedures for applying for a patent in different countries based on the Patent Cooperation Treaty. The paper also includes a comparison of the time needed for processing the patent application. Low cost provisional twelve-month patent pending protection available in the United States is also being discussed. The paper also provides some guidance and recommendations for conducting a patent search in order to validate the originality of the invention.

Open access

Petr Klouda, Vlastimil Moni, Michal Řehoř, Jan Blata and František Helebrant

Abstract

The article is a summary of information about evaluation of a risk degree for a brown coal spontaneous ignition which is realized on the base of a database analysis of information about the development of stative quantities and desorbated gases in the stored bodies of the brown coal. The data were gained from the long term complex measurements which were realized at chosen companies during the coal mining in the previous parts of the project. In the last part of the project, we examined results of temperature models from thermographs with results of gasses and coal samples from the mines. Then, the influence of atmospheric conditions (insolation, water downfall, changes of barometric pressure etc.), the influence of coal mass degradation, the influence of physical and chemical factors, and the influence of other defective factors on the process of the coal spontaneous ignition. The gasmetry was assess with gas in-situ samples and laboratory gas models of indicative gasses for the spontaneous ignition, which were taken from the method of the thermic oxidation with the aim of the correlation finding for an epicentre of temperature within the spontaneous ignition.