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Tytuł:
Research on the coefficient of friction of becorit K22 and K25SB linings
Autorzy:
Stawowiak, Michał
Żołnierz, Marcel
Rożenek, Zenon
Powiązania:
https://bibliotekanauki.pl/articles/2064401.pdf
Data publikacji:
2019
Wydawca:
STE GROUP
Tematy:
steel rope
coefficient of friction
lining
lina stalowa
współczynnik tarcia
wykładzina
Opis:
The article presents the method and results of experimental tests of the coefficient of friction between a steel rope and friction lining. The BECORIT K22 and BECORIT K25SB floor coverings were tested. The tests were carried out in accordance with the recommendations of the new German standard: DIN 21258 - Lubricants and impregnating agents for drive discs and transport ropes in mining - safety and testing requirements. The authors in this article emphasize that the Becorit K22 and K25SB linings are used for the wheels of propeller drums of mining machines. Characterized by high coefficients of friction (μ ≥ 0.25), also in cases of extreme weather conditions on the surface. The chemical properties of BECORIT linings ensure their resistance to swelling in the event of different oils and lubricants as well as mine waters. The material of which the claddings are made ensures very good machinability during rolling of rope grooves with the use of turning or milling tools. BECORIT K22 plastic cladding is particularly suitable for use in hoisting machines, where the rope base forms a large overlap angle on the wheel grooves (max 1°31'), which causes its lateral wear faster. BECORIT K22 material in this case provides a higher service life compared to other materials. Due to the way they are mounted on the wheel, they are made as 1-piece (monolith) or bipartite. In this article, moreover, the structure and principle of operation of the measuring station on which the tests were carried out are presented in great detail.
Źródło:
New Trends in Production Engineering; 2019, 2, 1; 367--375
2545-2843
Pojawia się w:
New Trends in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dry Sliding Friction and Wear Behaviour of Leaded Tin bronze for Bearing and Bushing Application
Autorzy:
Dinesh, D.
Megalingam, A.
Powiązania:
https://bibliotekanauki.pl/articles/2049132.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wear
coefficient of friction
microstructure
leaded tin bronze
grey relational analysis
Opis:
Among different bearing materials, copper-based alloys are the most important source for bearing and bushing applications. In this work, the tribological behavior of a leaded tin bronze (Cu-22Pb-4Sn) against an EN31 Steel for various loads (20 N, 70 N, 120 N) and different sliding velocity (1 m/s, 3 m/s, 5 m/s) at 3000 m sliding distance is performed using a pin on disk tribometer. Irrespective of all loads and sliding velocity, a higher specific wear rate is observed at 1 m/s and 120 n that fails to facilitate the formation of lubricating film, whereas a lower specific wear rate is evident when the sliding velocity is increased to 5 m/s. This is attributed to the formation of a stable oxide layer that has been confirmed through the energy dispersive X-ray spectroscopy analysis and scanning electron microscopy. The coefficient of friction is observed in reducing trend from 0.69 to 0.48 for the increasing load (70 N, 120 N) and sliding velocity (3 m/s and 5 m/s) due to stable thin oxide film formation. Also, the increase in frictional force and loading the interacting surface temperature is increased to a maximum of 102°C. The grey relational analysis indicates that the optimal parameters for the minimum specific wear rate and coefficient of friction is 120 N and 5 m/s that has been confirmed with experimental analysis.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 4; 1095-1104
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected tribological parameters for silumin alloy used for engine piston
Autorzy:
Kozuba, J.
Wieszała, R.
Mendala, J.
Roszak, M.
Pakieła, W.
Powiązania:
https://bibliotekanauki.pl/articles/2175806.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
tribology
piston engines
coefficient of friction
tribologia
silniki tłokowe
współczynnik tarcia
Opis:
Purpose: The conducted tests were aimed at determining whether the tested material meets the requirements for wear resistance in modern turbocharged combustion engines where there is an increased temperature and higher pressure. Design/methodology/approach: The tests were performed in a pin-on-disc system, according to the ASTM G 99 standard. Findings: The article presents the results of the coefficient of friction, the amount of wear, chemical analysis and surface profile of the tested material A390.0 in combination with EN GJL-350 cast iron. Research limitations/implications: The tested materials are used in the construction of pistons for internal combustion engines, therefore the test parameters were selected to take into account the operating conditions in a turbocharged engine with a power of up to 100 kW. Practical implications: After analysing the properties of the A390.0 alloy at elevated temperatures, it was found that without additional modifications, the alloy cannot be used in modern combustion engines, in particular with turbocharging. Originality/value: Presents the results of research concerning mechanical properties (HB, HV, Rm) and yield properties (R0.2, A5, Z) of the examined alloy.
Źródło:
Archives of Materials Science and Engineering; 2021, 107, 2; 64--71
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wykorzystanie modelu DEM do symulacji oddziaływań międzycząsteczkowych
Application of DEM approach for predicting particles interactions
Autorzy:
Widuch, Agata
Powiązania:
https://bibliotekanauki.pl/articles/101705.pdf
Data publikacji:
2016
Wydawca:
Politechnika Śląska. Wydział Inżynierii Środowiska i Energetyki. Instytut Techniki Cieplnej
Tematy:
CFD
DEM
cząsteczka
współczynnik tarcia
particle-particle interaction
coefficient of friction
Opis:
Modele komputerowe coraz częściej znajdują zastosowanie w bardzo wielu gałęziach przemysłu, szczególnie do modelowania złożonych zjawisk cieplno-przepływowych. Jednym z przykładów może być energetyka zawodowa, gdzie modele komputerowe wykorzystywane są do optymalizacji procesu konwersji energii chemicznej paliwa w ciepło użyteczne wykorzystując kotły pyłowe oraz fluidalne. Obecnie szczególnym zainteresowaniem cieszy się ta druga grupa dzięki ich dużej sprawności, małej wrażliwości na jakość spalanego paliwa, oraz możliwości łatwej redukcji NOx, a także wychwytu SOx. W celu zamodelowania silnych odziaływań międzycząsteczkowych zachodzących w warstwie fluidyzującego materiału konieczne jest stosowanie odpowiednich modeli wielofazowych. Do modelowania przepływu wielofazowego może być stosowana metoda Eulera, hybrydowy model Euler-Lagrange oraz modele bazujące na metodzie elementów dyskretnych (ang. Discrete Element Method – DEM). Podejście DEM, w porównaniu ze wspomnianymi dwoma technikami obliczeniowymi pozwala na fizyczne uwzględnienie oddziaływań międzycząsteczkowych [1], umożliwia modelowanie pękania czy aglomeracji ziaren. Technika DEM jest alternatywą dla metod opartych na koncepcji ciągłości ośrodka, dająca możliwość odwzorowania bezpośrednich interakcji między cząstkami. W porównaniu z metodą Eulera, podejście DEM nie jest zbyt popularne w przypadku jego stosowania do modelowania procesu fluidyzacji. W prezentowanej pracy sprawdzono możliwość wykorzystania modelu DEM do modelowania oddziaływań międzycząsteczkowych na poziomie ziarnowym.
The applications of numerical techniques for modeling of various industrial processes are getting very popular. One of the examples can be found in energy sector where advanced numerical models are often applied for optimization of the fuel chemical energy conversion processes into the useful form of energy. This process generally occurs within pulverized or fluidized coal boilers. Over the years, the popularity of the second boiler group constantly increased, mainly due to the reason that they are less sensitive to fuel quality and ensure high conversion of fuel into heat. Nevertheless, it is not a trivial task to simulate all interaction between particles, which occur during fluidization process. The fluidization process in nature is very complex and requires a specific approach. Multiphase flow can be simulated using Euler-Euler, hybrid Euler-Lagrange approaches or using the Discrete Element Method (DEM). The DEM approach contrary to both earlier mentioned techniques takes into account impact of material properties on the particles collision process. The DEM approach compared to the Euler-Euler technique has not been well tested yet for modelling fluidization process. In the present work the strength and weakness of the DEM model has been tested using simple test looking on collision of individual or groups of particles.
Źródło:
Archiwum Instytutu Techniki Cieplnej; 2016, 2; 155-169
2451-277X
Pojawia się w:
Archiwum Instytutu Techniki Cieplnej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling the movement of broadcast on the concentration table
Autorzy:
Feliks, Jacek
Krawczyk, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/2064429.pdf
Data publikacji:
2019
Wydawca:
STE GROUP
Tematy:
concentration table
coefficient of friction
enrichment
tabela koncentracji
współczynnik tarcia
wzbogacanie
Opis:
The article attempts to analyze the work of the concentration table, on which the distribution of the material under investigation takes place. The efficiency of separation or otherwise enrichment depends on the drive that puts the concentration table plate into an asymmetrical reciprocating movement. The most frequently used solutions are concentration tables, on which the distribution of enriched material takes place in an aqueous medium commonly called wet enrichment. The AGH University of Science and Technology conducted simulation tests of material enrichment on a concentration table using the differences in friction coefficient commonly referred to as dry enrichment, i.e. without an additional medium. The article presents the effects of simulations that have been carried out for reference materials characterized by different friction coefficients and densities. The summary presents the analysis of obtained effects of computer simulations of material movement with different coefficients of friction. The simulations were carried out for variables: the frequency of vibrations of the concentration table and the angle of inclination of the table of the concentration table. It has been shown that it is possible to enrich the material by changing the above-mentioned operating parameters of the device.
Źródło:
New Trends in Production Engineering; 2019, 2, 1; 304--311
2545-2843
Pojawia się w:
New Trends in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods of enlarging material to the concentration table
Autorzy:
Feliks, Jacek
Krawczyk, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/2064376.pdf
Data publikacji:
2019
Wydawca:
STE GROUP
Tematy:
concentration table
coefficient of friction
enrichment
tabela koncentracji
współczynnik tarcia
wzbogacanie
Opis:
Concentration tables are one of the oldest oscillatory enrichments with over 100 years of tradition. On this type of distribution tables are made according to material mass in many recurring cycles induced by appropriate drives. So-called wet tables are the devices most often used for coal enrichment in Polish mines because this process generates very high costs, high water consumption and pollution of the environment, as well as the need for, among others, water and mud management is increasingly being replaced mainly in areas poor in water by the modern model of the air concentration table - FGX produced in China. The process of enrichment on this type of table itself runs in a manner comparable to the method of wet enrichment with the difference that the FGX is distributed on a perforated plate, in this case we deal with air pollution. Department of Machinery Engineering and Transport's attempts to use the differences in coefficients of friction in over-resonance screens have shown that it is possible effective separation of grains with different coefficients of friction. The article presents a theoretical analysis and presents the results of performed dry enrichment trials using different coefficients of friction. The summary presents the advantages of using the enrichment method using the differences in friction coefficients and test results.
Źródło:
New Trends in Production Engineering; 2019, 2, 1; 59--68
2545-2843
Pojawia się w:
New Trends in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frictional properties of selected seeds
Autorzy:
Kaliniewicz, Z.
Markowski, P.
Anders, A.
Jadwisieńczak, K.
Powiązania:
https://bibliotekanauki.pl/articles/298455.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
physical attributes
coefficient of external friction
relation
Opis:
The thickness, width, length and weight of five seed species (buckwheat, vetch, pea, lupine and faba bean) and their external friction angle were determined on two types of surfaces - steel and rubber. The experiment was performed with the use of a an inclined plane with an adjustable angle of inclination that measures the angle of external friction and the time taken by seeds to travel a given distance, which supports the determination of the coefficient of kinetic friction. The measured parameters were used to calculate arithmetic and geometric mean diameter, aspect ratio and sphericity index. The dimensions, weight and the calculated indicators of the examined seeds did not significantly affect their coefficients of static and kinetic friction or their coefficients of rolling resistance and rolling friction. The studied parameters were largely influenced by the type of friction surface, and significantly lower average values were reported for steel than rubber. In the studied seed species, the static friction coefficient was determined in the range of 0.187 to 0.582, kinetic friction coefficient - 0.134 to 0.479, rolling resistance coefficient - 0.148 to 0.529 and rolling friction coefficient - 0.29 to 1.80 mm.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2015, 18(2); 85-101
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Small high density lipoprotein subclasses: some of their physico-chemical properties and stability in solution.
Autorzy:
Atmeh, Ragheb
Abd Elrazeq, Issa
Powiązania:
https://bibliotekanauki.pl/articles/1041440.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
small high density lipoproteins
diffusion coefficient
surface charge
molecular shape
coefficient of friction
stability
Opis:
Small high density lipoproteins (SHDL) contribute to the protection from atherosclerosis, but detailed information about their properties is not available yet. We isolated four of the smallest HDL subclasses that contain apoA-I alone, the small lipoprotein A-I (SLpAI), by their separation on gradient polyacrylamide gel followed by electroelution. Their physico-chemical properties were calculated from their displacement in non-denaturing gradient polyacrylamide gel under the effect of electrical potential. The properties are: Stokes' radii 2.96-3.56 nm; molecular masses 42-70 kDa; net negative charge 7.2-13.5; surface charge densities 3139-4069 -esu∙˙cm^(-2); surface potentials 10.6-15.7 -mV; coefficients of friction 5.74-6.90 × 10-8 g∙˙s^(-1); and diffusion coefficients 5.76-6.94 7× 10-7 cm^2∙˙s^(-1). We found that these particles were of low stability as they underwent molecular transformation into larger particles on storage. The estimated dimensions of these particles do not support ellipsoidal shape, therefore, the most probable shape is spherical; consequently, their hydrated characteristics were estimated. We conclude that these particles have high values of negative surface charge and diffusion coefficients, and are of low stability. Their small Stokes' radii were similar to each other and they are spherical and highly hydrated.
Źródło:
Acta Biochimica Polonica; 2005, 52, 2; 515-525
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Friction Forces in the Process of Forming Moulding Mass
Analiza tarcia zewnętrznego w procesie formowania mas formierskich
Autorzy:
Szewczyk, Marek
Szwajka, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/27310178.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
coefficient of friction
stresses
strain gauges
forming
współczynnik tarcia
naprężenia
tensometry
formowanie
Opis:
Accelerated wear of the moulds' inner surface used in forming loose masses contributes to its frequent replacement or regeneration. This wear is indirectly influenced by the high pressure accompanying the compaction process, but the main cause of accelerated wear is the friction that occurs between the die and the compacted medium. Knowing that the value of the internal pressure in the moulded medium changes with the change of the distance from the punch, in order to properly understand the phenomena accompanying the friction that occurs in the mould during the pressing process, its characteristics must be determined. The paper analyses the distribution of forming pressure inside the mould during the compaction of high-silica sand. The deformation on the die surface was measured using strain gauges, and x-ray tomography was used to visualise the compaction of high-silica sand during the compaction process. The usefulness of an indirect method for measuring the friction coefficient based on the analysis of die deformation has been demonstrated.
Przyśpieszone zużycie powierzchni wewnętrznej form, stosowanych w procesach formowania mas sypkich, przyczynia się do częstej jej wymiany lub regeneracji. Na zużycie to pośrednio wpływa wysokie ciśnienie towarzyszące procesowi zagęszczania, ale główną przyczyną mającą wpływ na przyspieszone zużycie jest tarcie, które występuje pomiędzy matrycą a medium zagęszczanym. Wiedząc, że wartość ciśnienia wewnętrznego w medium formowanym zmienia się wraz ze zmianą odległości od stempla, dla prawidłowego zrozumienia zjawisk towarzyszących tarciu, które zachodzi w formie podczas procesu prasowania, należy więc określić jego charakterystykę. W pracy przeanalizowano rozkład ciśnienia formującego wewnątrz formy podczas zagęszczania piasku wysokokrzemionkowego. Odkształcenie na powierzchni matrycy mierzono za pomocą tensometrów. W celu zobrazowania zagęszczania piasku wysokokrzemionkowego podczas procesu zagęszczania zastosowano tomografię rentgenowską. Wykazano przydatność zastosowania pośredniej metody do pomiaru współczynnika tarcia opartej na analizie odkształceń matrycy.
Źródło:
Tribologia; 2023, 1; 65--75
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Cryogenic Treatment on Wear Resistance and Microstructure of 42CrMo Steel
Autorzy:
Zhang, Haidong
Yan, Xianguo
Chen, Zhi
Zhao, Minna
Tang, Liang
Gao, Yuan
Li, Fan
Huang, Yao
Li, Junji
Powiązania:
https://bibliotekanauki.pl/articles/2048794.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cryogenic treatment
orthogonal design method
hardness
coefficient of friction
wear resistance
microstructure
Opis:
In this work, thermo-mechanically treated 42CrMo steel was subjected to cryogenic treatment conducted by means of orthogonal design method, followed by low-temperature tempering to investigate the effect of different parameters of cryogenic treatment on wear resistance of 42CrMo steel and to optimize parameters of cryogenic treatment for improving wear resistance. The results of hardness test and wear test show that cryogenic treatment significantly improves wear resistance with marginal changes in coefficient of friction and hardness. Specifically, cryogenic temperature has the largest impact on wear resistance of 42CrMo steel, holding time has medium impact, and the parameter of treatment cycles has the least impact. The optimum parameters of cryogenic treatment are -196°C for 12 hours with one cycle for improving wear resistance. The results of scanning electron microscopy (SEM) and X-ray diffractometry (XRD) analysis indicate that marginal changes in hardness and coefficient of friction may be owing to little amount of transformation of retained austenite, and the significant influence of cryogenic treatment on improving wear resistance of 42CrMo steel can be mainly attributed to segregation of carbon atoms promoted by cryogenic treatment resulting in more precipitation of carbides in subsequent tempering.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 1; 127-135
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-10 z 67

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