bluuebunny/crossref_metadata_2025 huggingface dataset:
THE ANALYSIS OF THE INFLUENCE OF LASER HEAT TREATMENT OF THE CRANKSHAFT JOURNAL ON WEAR RESISTANCE OF THE BEARING
Authors: PACZKOWSKA Marta
Published: November 2018

The aim of the presented research was to evaluate wear effects of bearing elements in case of modification based on laser alloying with boron of journal surface layer. The research was performed on ZPG-IV tribology tester with journal-bearing friction pair. During the test load was applied progressively. SEM microscopes and non-contact 3D optical profilografometr was used to assess the test results. Study of the character of the wear process allowed to state, that after each increase of load during the test, rapid change of the value of oil temperature and the value of resistance in journal-pan contact was appeared. Then, the stabilization period was followed by. Some differences in the way of those processes between tested variants were noticed. Firstly, during the stabilization period larger thickness of the oil film at the journal-pan interface was notice in case of journal after laser treatment than in case of untreated journal. Secondly, it could be expected that oil temperature will be lower in case of longer time of tribological test for treated journal (than for untreated journal). It should favor better wear resistance of this kinematic node. Macro and microscopic observations of both types of surface after wear test allow to state, that journals after laser treatment were characterized by less wear effects, as cavities in the surface layer in comparison to untreated journals. More intensive wear of journals without treatment was confirmed by stereometric research and measurements of surface roughness parameters. This research allow to state positive laser treatment influence on the wear resistance of the journal. Although, there was no larger loss of the surface layer in case of pans after cooperation with hard journal after laser treatment (describe by the decrease of pans’ thickness) then loss of the surface layer in case of pans after cooperation with softer untreated journal (nearly 5-times softer than the surface layer of treated journal), the microscopic observations and measurement of the parameters of stereometric structure of their surface showed more intensive wear of pan after cooperation with treated journal.
THE INFLUENCE OF THE LOAD AND JOINT CARTILAGE ELASTICITY MODULES ON SYNOVIAL FLUID VISCOSITY
Authors: WIERZCHOLSKI Krzysztof , SÓJKA Michał
Published: November 2018

During classical journal bearing lubrication the lubricant viscosity is independent of physical properties of cooperating bodies, which is well known by virtue of Hersey-Stribeck (H-S) curve presenting friction coefficient vs. Hersey number = viscosity´velocity/pressure. The result obtained by the H-S is valid for two cooperating bodies with homogeneous, isotropic properties, and for Newtonian oils omitting the elastohydrodynamic effects. In the presented paper, we take into account the two cooperating human joint cartilage surfaces, which, after new AFM measurements, have non-homogeneous hypo- or hyper-elastic properties, and the synovial fluid has non-Newtonian features. Moreover, the cartilage surface during human limb motion and during the squeezing and boosted squeezing effects gains important small deformations. From the abovementioned description, it follows that the H-S result cannot be acceptable in human joint lubrication [L. 1–6]. During human joint hydrodynamic lubrication, we observe the influence of the material coefficients of the hypo- and hyper-elastic cartilage tissue on the apparent viscosity of non-Newtonian synovial fluid occupying the thin joint gap limited by the two cartilage superficial layers. This problem has not been considered in scientific papers describing the hydrodynamic lubrication of the human joint. This problem attains significant meaning because, after numerous AFM laboratory measurements confirmed by the literature achievements, it follows that the joint cartilage tissue with a thin polar membrane made of two lipid molecules has no isotropic but anisotropic properties in general. These membranes are flat sheets that form a continuous barrier around the cartilage cells. Non-homogeneous, anisotropic biological bodies as distinct from classical isotropic materials have the various values of elasticity, hypoelasticity, or hyper-elasticity modules on individual places and directions. These places, loaded by the same forces, tend to various displacements and strains. In consequence, mutually connected physical implications caused by virtue of synovial fluid flow velocity and shear rates changes, indicate to us the conclusion that the dynamic viscosity of synovial fluid gains value variations caused by the cartilage’s physical properties during human joint lubrication.
THE INFLUENCE OF LOCATION OF THE SURFACE OF LOAD ON THE VALUE OF PRELOAD IN THE SYSTEM OF ANGULAR CONTACT BALL BEARINGS
Authors: KACZOR Jarosław , RACZYŃSKI Andrzej
Published: November 2018

Angular contact ball bearings are commonly used when high stiffness of the bearing is needed. However, a significant stiffness increase can be achieved only through introducing preload (mounting tightness) to the system of angular ball bearings. The aim of the study is to determine how the location of a plane of a load influences the selection of preload in a system of angular contact ball bearings, and, in consequence, the durability of the bearing.
THE IMPACT OF BIODEGRADABLE CUTTING FLUID ON THE TRIBOLOGICAL PROPERTIES OF THE FRICTION PAIRS
Authors: OZIMINA Dariusz , KOWALCZYK Joanna , MADEJ Monika
Published: November 2018

This paper discusses the results of wear tests performed with a T-01 M tribometer for a ball-on-disc configuration in sliding contact. The tests were carried out for HS6-5-2C steel discs with and without a TiAlN coating deposited by physical vapour deposition (PVD), which were in contact with 100Cr6 steel balls. The tests were conducted under dry friction conditions and under lubricated friction conditions with a cutting fluid containing zinc aspartate. The coating structure was observed using a JSM - 7100F scanning electron microscope. The surface texture of the discs and the balls was analysed as well as good adhesion to the substrate. Coated tools can operate under dry and wet machining conditions, and they improve the operating parameters of the element. Such coatings can be produced by chemical vapour deposition (CVD), physical vapour deposition (PVD), or similar techniques [L. 8, 4, 13].
EFFECT OF COARSE-TO-FINE WC GRAIN RATIO
ON MECHANICAL PROPERTIES AND ABRASIVE
WEAR OF WC-8Co CEMENTED CARBIDES
Authors: YUNG Der-Liang , ANTONOV Maksim , HUSSAINOVA Irina , VEINTHAL Renno , HOGMARK Sture
Published: November 2018

This study performs a comprehensive analysis concerning the amount of fine
tungsten carbide (WC) grains needed for the appropriate reinforcement of the
cobalt (Co) metallic binder in WC-8Co cemented carbides. The goal is to
investigate the balance of coarse-to-fine grain distribution to achieve overall
improvement of the material’s mechanical and wear properties. All samples possessed the same WC-8Co binder content, therefore, allowing the role of
grain size distribution to be tested. It was found that a ratio of 8:1 wt% of coarse
to ultrafine grain WC yielded an appropriate balance between material hardness,
fracture toughness, and rupture strength. Upon adding grain growth inhibitors
vanadium carbide (VC) and chromium carbide (Cr3C2), the overall wear
resistance is further improved compared to undoped composites when samples
are tested under abrasive wear conditions.
THE SELECTION OF PRELOAD IN ANGULAR CONTACT BALL BEARINGS ACCORDING TO THE CRITERION OF MOMENT OF FRICTION
Authors: KACZOR Jarosław , RACZYŃSKI Andrzej
Published: November 2018

The article [L. 3] presents a method of preload selection in angular contact ball bearings based on their durability. The preload can be expressed as a force or as a dislocation (distance). Depending on the regulation method, the preload is also indirectly connected with the moment of friction in a bearing. The objective of the paper is to determine a maximum preload in angular contact ball bearings, based on the moment of friction in a system of bearings.
THE INFLUENCE OF SELECTIVE LASER SINTERING PARAMETERS ON TRIBOLOGICAL PROPERTIES OF PA 3200 GF POLYAMIDE
Authors: KUNDERA Czesław , KOZIOR Tomasz
Published: November 2018

The paper presents the preliminary results of tribological research on the material used in the selective laser sintering technology, SLS. The samples in the shape of rings were manufactured of PA 3200 GF polyamide powder additionally reinforced with glass fibre, which is based on pure PA 2200 polyamide. The tests were carried out on a tribological T-15 tester, ring-on-disc type imitating the cooperation conditions of elements, e.g., the rings of the contact active seal. The main objective of the research was to determine the influence of the direction of the positioning of the models on the construction platform on the coefficient of friction and the wear of the cooperating friction pair components.
STUDY OF SELECTED USABLE PROPERTIES OF THE TOP LAYERS OF WELD OVERLAYS PRODUCED BY LASER TECHNOLOGY FOR APPLICATIONS IN THE POWER INDUSTRY
Authors: NAPADŁEK Wojciech , WOŹNIAK Adam , CHRZANOWSKI Wojciech
Published: November 2018

The paper presents the results of laboratory tests of test specimens produced by multi-layer laser padding alloy Stellit Co-6 powder on a substrate with heat-treated X22CrMoV12-1 alloy steel. Multilayer laser padding was performed on a TRUMPF TruLaser Cell 3008. The formed weld overlays surface was studied using an optical microscope. Selected usable properties, such as surface topography, microstructure, hardness and erosion resistance were studied. During the analysis, areas of cross-sections test specimens after multilayer laser padded, in the connection zone of the substrate material with weld overlay, no cracks and no discontinuities in weld overlay were found in the substrate. As a result of conducted experiments, regular, repetitive weld overlays with characteristic directional crystallization were obtained. A microstructure with different growth directions with respect to the surface of the substrate shaped coniferous dendrites was obtained. The hardness of the weld overlays was in the range from 420 to 620 HV0.1, and in the heat affected zone, in the range of 320 to 420 HV0.1. Significant increases in erosion resistance of the surface layer of Stellite type Co-6 weld overlay produced by laser in comparison with the parent material after hardening were found.
THE INFLUENCE OF THE ADDITION OF GRAPHITE
ON THE TRIBOLOGICAL PROPERTIES OF POLYLACTIC (PLA)
APPLIED IN 3D PRINTING TECHNOLOGY
Authors: PAWLAK Wojciech , WIELEBA Wojciech , KLUCZYŃSKI Janusz , ŚNIEŻEK Lucjan
Published: November 2018

The article presents the results of studies on the influence of the addition of graphite to a PLA filament
on linear wear and the coefficient of friction. A cylinder of 8 millimetre diameter manufactured in Fused
Filament Fabrication process, popularly called 3D printing was used as a specimen. Studies were conducted
on pin-on-disc testing machine, in which the cylinders mentioned above were paired with a steel disc –
the counter-specimen. Specimens used in research were enriched by 5%, 10%, 20%, and 30% of graphite
in comparison to the base filament – Natural PLA, which were not enriched with any additions that could
improve its tribological properties. The experiment was conducted as a preliminary research. The gained
results create a basis to select the optimal composition of additions to the PLA to create a filament with better
tribological properties.
INFLUENCE OF PAD GEOMETRY MODIFICATION ON THE PERFORMANCE OF THRUST BEARINGS LUBRICATED WITH MAGNETORHEOLOGICAL FLUID
Authors: HORAK Wojciech , SZCZĘCH Marcin , SALWIŃSKI Józef
Published: November 2018

Magnetic fluids belong to the class of controllable materials. The influence of magnetic fields on this type of substance results in a change in its internal structure and an almost immediate change in its rheological properties. The ability to control the rheological characteristics in a very wide range, in combination with the ease of generating and controlling the magnetic field, creates the possibility of using this type of substance in systems with controlled operating parameters. The use of magnetic fluids in bearings may allow the design of some types of bearings to be simplified and enable efficient, fast, and precise control of the system operation, with a much shorter response time and higher stiffness than is the case with conventional sliding friction bearings. The paper presents the results of experimental tests carried out on a laboratory stand designed for thrust bearings lubricated with magnetic fluids. The analyses carried out concerned the determination of how the pad surface modification of the slide bearing, lubricated with magnetorheological fluids, influences the system performance parameters.
INFLUENCE OF BICYCLE BRAKE SYSTEM ON USERS SAFETY
Authors: POSMYK Andrzej , JEZUSEK Mateusz
Published: November 2018

In many big cities, for example, Silesia Conurbation, in order to limit the negative results of automotive vehicles operation, toll bicycle rental stations have been actuated. Their users are incidental persons. Therefore, the safety of a traffic participant on bicycle ways and on areas with bicycle traffic depends on the sufficiency of braking systems. In the bicycle industry, there are many of types of brake systems from mechanical to hydraulic. A common part of the brake systems is a friction contact. In this paper, the results of tribological examination of materials used for bicycle brakes have been presented. Tribological investigation (coefficient of friction, wear rate) of classic (the oldest) rubber pad/AW-6061 alloy wheel band, composite with thermoplastic matrix/steel and AW-6061 alloy wheel band as well as friction composite with duroplastic matrix/steel brake disc contacts have been conducted. Microscopic observations of examined materials surfaces have been done and the wear mechanisms have been explained. A preliminary estimation of the influence of used materials on the safety of a traffic participant has been done.
ANALYSIS OF THE MAGNETIC FIELD DISTRIBUTION IN THE PARALLEL PLATE RHEOMETER MEASURING SYSTEM
Authors: SZCZĘCH Marcin , HORAK Wojciech
Published: November 2018

Magnetic fluids are materials whose physical properties can be changed by a magnetic field of a given intensity value. One of the fundamental research areas for determining the properties of magnetic fluids is rheological measurement. The basic method for determining the rheological properties of this type of smart material is by using rotational rheometers equipped with parallel plate measuring geometry. The paper presents the results of numerical simulation and experimental research on the magnetic induction distribution in the working gap for this type of measuring geometry. The conducted analyses allowed the influence of selected parameters on the uniformity of the magnetic field distribution in the magnetic fluid to be determined. The work paid attention to the problems occurring in the development of measuring systems for determining the properties of magnetic fluids under the conditions of a magnetic field.
METHOD OF PAINT COAT DURABILITY ASSESSMENT EXPOSED TO MINERAL MASS
Authors: SZCZYGLAK Piotr
Published: November 2018

This study analyses issues concerning defects of passive paint coats. Four reasons of their occurrence have been identified: constructional, technological, operational, and caused by wear and tear. Standardized methods of paint coat assessment are discussed based on the impact of mechanical factors (PN-EN ISO 2409:2013-06, ASTM D3359-17, PN-EN ISO 1522:2008, PN-EN ISO 4624:2016-05, PN-EN ISO 1518-1:2011, PN-EN ISO 16276-2:2008, PN-EN ISO 6272:2011, PN-EN ISO 6860:2006, PN-EN ISO 2815:2004, PN-EN ISO 1519:2000). The original method of paint coat durability evaluation is presented with the consideration of synergetic impact of mechanical forces. This method permits carrying out testing in conditions close to those during normal service. The testing stand equipped with a rotating drum filled with mineral mass has been described as well as the optical method of assessing paint coat quality using original software developed by authors. Tests for three coating systems were carried out in order to present the possibilities of the developed method. In summary, the conclusions relating to the presented testing method are presented.
ESTIMATION OF THE WEAR MECHANISM IN SLIDING CONTACT
OF SATELITE GEARS OF A HYDRAULIC MOTOR
Authors: BĄKOWSKI Henryk
Published: November 2018

The paper presents tests of the wear of selected elements of a hydraulic satellite engine in sliding contact.
The tests were carried out on the tribotester T-05 in a roll-block system, taking into account the influence
of the most important operational parameters determining the durability of the friction node in question.
The performed tribological, metallographic and profilographometric studies allowed the comparison and
evaluation of the mechanism of sliding contact wear in the laboratory stand and on the real object, which
allows one to make far-reaching assumptions about the durability of the contact in question and its resistance
to wear under various operating.
THE USE OF METALLOGRAPHIC ANALYSIS OF FRICTION
LININGS IN THE BRAKING SYSTEM TO DETERMINE
THE PROCESSES OF TRIBOLOGICAL WEAR
Authors: BĄKOWSKI Henryk , STANIK Zbigniew , CHMIELA Bartosz
Published: November 2018

The work presents metallographic examinations of worn brake linings under various operating conditions. The
main purpose of this work is to determine the types of friction pair wear of braking systems under specific operating
conditions. This is important for car service employees and appraisers who, based on quantitative and qualitative
analysis, will determine the dominant mechanisms of wear. This is very important due to the possibility of determining
the operating conditions, and thus the assessment of the use not only of the friction pair, but also the entire technical
object, which is a motor vehicle. On the basis of the quantitative metallographic analysis of the research, individual
wear mechanisms were presented, taking into account the determined diagnostic criteria during the measurement.
THE EFFECT OF SURFACE TEXTURING ON THE FRICTIONAL
RESISTANCE OF STEEL-BRONZE ASSEMBLY IN LUBRICATED
SLIDING
Authors: KOSZELA Waldemar , GAŁDA Lidia , DZIERWA Andrzej , PAWLUS Paweł , SĘP Jarosław , OCHWAT Sławomir
Published: November 2018

The experiments were carried out using a block-on-ring tester. The block samples made from bronze CuSn10P
of 138 HB hardness were burnished to obtain surfaces with circular oil pockets. Rings were made from
42CrMo4 steel of hardness 40 HRC. Friction tests were conducted at a constant normal load of 900 N. Tests
were carried out at increasing sliding speeds of the range 0.08 – 0.82 m/s, starting from the lowest speed. The
every speed was maintained for two minutes. The tested assembly was inserted in the reservoir of mineral oil
L-AN 46.
It was found that the dimple presence on block surface reduced the friction coefficient substantially compared
to non-textured turned surfaces. The area density of dimples smaller than 15% (particularly 4.5% and 6%) was
beneficial.
THE INFLUENCE OF UNIAXIAL COMPRESSION ON THE FRICTION COEFFICIENT (POLYMER–STEEL PAIR), WEAR, AND HARDNESS IN SELECTED THERMOPLASTICS
Authors: KUJAWA Maciej
Published: November 2018

Plastic plain bearings are deformed during assembly. According to one of the leading manufacturers of plastic sliding elements, the bushing’s internal diameter may be reduced by up to 2.5%. Moreover, plastic sliding elements are increasingly used in harsh conditions (e.g., under high pressure). However, there are no papers that describe the influence of deformation under compression on the tribological properties of plastics. Specimens made of PTFE, PA6, and PE-HD were deformed while conducting the current research, and this deformation was maintained during cooperation with steel. The results of microhardness, wear, and the coefficient of friction tests were compared to data gathered during tests of non-deformed specimens. During deformation under compression (e ≈ 6%), microhardness lowered by up to 30% (PTFE). A significant reduction of hardness (by up to 15%) was observed when strain was only 2%, and up to this value of strain, there is mainly elastic deformation in the polymer. Changes of the coefficient of friction values were insignificant. In terms of PTFE and PE-HD, during deformation under compression up to e ≈ 6% , the block scar volumes were 20% and 40% larger, respectively, than the non-deformed form of specimens. In terms of PA6, the change in block scar volume was insignificant. It may seem that tension and compression ought to cause totally different effects. However, the comparison of the current results and the results described in the previous paper exposes that these two different processes led to the same effects – reducing hardness and increasing wear. Deformation of plastic sliding components as an effect of assembly appears to be minor; however, it affects polymer microhardness and wear resistance.
INFLUENCE CuAl10Fe3Mn2 ADDITI VE ON ULTIMATE TENSILE STRENGTH AND WEAR OF Al-9%SiMg ALLOY
Authors: LIPIŃSKI Tomasz
Published: November 2018

One of the most common castings applied in industrial production is aluminium-silicon alloy (ca. 9% Si with Mg). The Al-SiMg alloys have high corrosion resistance, high strength to weight ratio with modifications, very good castability, a low thermal-expansion coefficient, and relatively good wear resistance. These properties make it possible to widely apply the foundry Al-9% SiMg alloy to number of aviation, automotive, and others materials working on tribological applications. Similar to silumins, the aluminium bronze CuAl10Fe3Mn2 is characterized by good mechanical properties and wear and corrosion resistance. This paper presents the research on the treatment of Al-9%SiMg alloy with a composition of CuAl10Fe3Mn2 in different mass ranges. The experiments were conducted by a factor plan 23 for three independent variables. The main additions were strontium, Al-9%SiMg, aluminium bronze, as well as pure or melted with raw silumin. The effect of the tested additions on the microstructure and tensile strength of the Al-9%SiMg alloy was presented in figures. All analysed parameters (mechanical and tribological) of the hypo-eutectic Al-9%SiMg alloy with tested bronze additions are improved. Based on the analysis of the study results, it was found that the microstructure and tensile strength of the tested alloy are determined through the contents introduced of CuAl10Fe3Mn2 to the alloy.
ANALYSIS OF THE TEMPERATURE VALUE IN CONTACT STEEL –
SOIL MATERIAL IN RELATION TO THE TYPE
OF CONSTRUCTION MATERIAL
Authors: NAPIÓRKOWSKI Jerzy , LEMECHA Magdalena
Published: November 2018

The article presents a study of the friction temperature at the contact soil soil-material. For the tests, samples
of 38GSA steel padded with El-Hard 63 electrode and Hardox 600 steel were selected. The experiment was
carried out in laboratory conditions using the “rotating bowl” method in two soil types with different humidity.
For light soil abrasive, the change in humidity increased the mass consumption in the wet soil almost twice
for Hardox 600 steel and 1.5 times for the steel 38GSA welded. However, in the middle soil, the 38GSA
steel was characterized by a higher wear value. The research shows that there were significant differences in
consumption between the tested materials.
STEADY-STATE ANALYSIS OF JOURNAL BEARINGS WITH HELICAL GROOVES
Authors: SĘP Jarosław , TOMCZEWSKI Leszek , GAŁDA Lidia
Published: November 2018

The spiral groove on the sliding journal surface enables the contaminants and eventual wear debris removal from the contact zone and bearing clearance. In this way, the wear and seizure resistance of slide bearings operating in difficult conditions became greater. The presence of a groove on bearing’s surface affects the hydrodynamic performance of the bearing. The aim of the article is to study the load carrying capacity, oil flow rate, and maximum oil temperature and pressure of slide bearings with a spiral groove at different operational conditions. Simulations were realized with the adiabatic, three-dimensional model of the oil flow in the bearing clearance. The oil flow was determined with the Navier-Stokes, continuity, and energy equations. The finite volume method was applied for calculations in ANSYS Fluent software. As a result of the investigations, it has been stated that, with the sliding velocity increase, the load capacity also increased, but the load capacity of the grooved journal was smaller than that of plain bearings. The maximum oil temperature in the bearing clearance of grooved journal bearing was lower than that of smooth ones, and, with the sliding velocity increase, the maximum temperature also increased. The oil flow rate was greater for the grooved series than for the smooth seies at all examined velocities and clearances.
STATIC FRICTION OF REVERSE STEEL–ELASTOMER SLIDING
PAIRS
Authors: WIELEBA Wojciech , OPAŁKA Mariusz
Published: November 2018

Sliding cooperation of materials with different hardness (deformability), e.g., a polymeric material cooperating
with metallic materials, occurs in machine elements in one of the following two variants: a conventional pair
or a reverse pair.
In the case of the conventional sliding pair, the deformation area (contact area) of the sliding materials does
not move on the surface of the polymer element during their cooperation. In the case of reverse pairs, the
contact surface changes its position when moving on the surface of the polymer element. Depending on
the variant of the sliding pair, the differences in the friction and wear process of polymer material can be
observed.
Tribological investigations of chosen sliding pairs (elastomer on steel or steel on elastomer) in the static friction
were carried out on the rig. The polymeric materials selected for the tests were thermoplastic elastomers TPU,
PUR, and silicone rubber SI. These materials co-operated with C45 steel in the different contact pressures
(p = 0.1 – 0.26 MPa) under dry friction or mixed lubrication conditions (hydraulic oil Hipol HLP-68). Based
on the recorded value of the friction force Ft, the values of static coefficients of friction μstat were determined.
The test results showed a significant influence of the variant of the combination of materials (metal-polymer
or polymer-metal) on the value of the friction coefficient. In all tested pairs in which steel sample (pin) slid
against elastomeric plates, the friction coefficient was higher than in the case when the elastomeric sample
(pins) cooperated with steel counterfaces (plates). The main reason is the considerable value of the deformation
component of the friction force. This is probably due to the displacement of the elastomer deformation area in
its surface layer and energy dissipation as a result of stress-strain hysteresis in the elastomeric material, as in
the case with reversed pairs.
THE INFLUENCE OF ADDED WATER ON FUEL INJECTOR WEAR IN A DIESEL ENGINE
Authors: WRÓBLEWSKI Aleksander , LANGER Agnieszka , SZCZYGLAK Piotr , REKUĆ Adam
Published: November 2018

The article presents the problem of the wear of the components of injection apparatus of a self-ignition engine during the addition of water. The observer was subject to an injector from the KIPOR KDE3500E generator set engine. The tests carried out consisted in observing the atomizer after 120 minutes of running the engine powered with diesel oil and after working at the same time but with the addition of water to the intake manifold.
MODIFICATION OF THE T-17 TESTER HOLDER TO ENABLE TRIBOLOGICAL TESTS TO BE CARRIED OUT IN A ROLLER-PLATE COUPLE
Authors: BARA Marek
Published: November 2018

The aim of this paper is to propose a solution that will make it possible to perform tribological tests of materials intended for rolling elements (e.g., rollers) interacting with a flat surface (e.g., sliding door guide). Tribological tests were carried out on a T-17 test stand, which was equipped with a holder that made it possible to perform tests in the roller-plate couple. The paper presents the results of tribological tests of a typical polymer PA 6 used in sliding door systems interacting with anodised and non-anodised aluminium alloys. The analysis of the tribological tests was supplemented by stereometric studies. The studies showed the possibility of performing tests for the roller-plate couple with the use of a T-17 test stand. The influence of the modification of the aluminium alloy surface (material of the sliding door guide) on tribological properties of the examined friction node was also shown.
EFFECT OF A TORSEN DIFFERENTIAL MECHANISM
ON CAR TYRE WEAR
Authors: KOLATOR Bronisław , JANULIN Michał , VRUBLEVSKYI Oleksandr
Published: November 2018

4WD systems include various constructions aimed at optimal distribution of torque between drive axles. In
these systems, it is necessary to apply mechanisms separating the power provided from the engine to drive
wheels. Many systems operate on the basis of wet multi-disc clutch or/and dog clutch control with the use
of mechatronic devices. However, in view of their reliability and construction simplicity, the most valuable
4WD systems under field conditions are mechanical solutions. Torsen is an inter-axle differential mechanism,
where the emerging internal friction moment of this mechanism causes that all kinematic discrepancies
between transmission shafts of the front and rear axle of a vehicle produce a change in the distribution of
torque, helping to level the rotational speeds of transmission shafts of the front and rear axles. As a result
of the phenomenon described, the drive wheels of both axles of the vehicle move with different peripheral
speeds, which causes energy losses and wear of tyres on both vehicle axles. This paper presents an analysis
of the results obtained in tests on a vehicle with the Torsen system and describes phenomena occurring in the
examined system as a result of emerging kinematic discrepancies, which may be caused by such factors as
vertical force acting on the wheels of individual drive axles and tyre pressure.
THE EFFECT OF SURFACE TEXTURE OF STEEL DISC
ON FRICTION AND FRETTING WEAR
Authors: LENART Agnieszka , PAWLUS Paweł , DZIERWA Andrzej , TUPAJ Mirosław
Published: November 2018

Fretting tests were performed using an Optimol SRV5 tribotester in a ball-on-flat scheme. Balls from 100Cr6
steel of 60 HRC hardness and diameters of 10 mm co-acted with discs from 42CrMo4 steel of 47 HRC hardness
under dry gross fretting conditions. Tests were performed at 300C and 25–35% relative humidity, and the
number of cycles was 18000. During each test, the normal load was kept constant. Six sets of experiments
were conducted. Discs had different surface textures as the result of machining. It was found that the lowest
coefficients of friction were obtained for anisotropic surfaces when ball movements were perpendicular to
main disc texture directions.
ANALYSIS INTO THE INFLUENCE OF SELECTED TOOTHED GEAR PARAMETERS ON THE VALUE OF SLIPPAGE AND CONTACT STRESSES IN A CYLINDRICAL GEARBOX
Authors: MARTYNA Marek , ZWOLAK Jan
Published: November 2018

The paper presents issues concerning the geometrical and durability calculations of power shift gearboxes with multi-criterion optimization, using proprietary computer software. Among many parameters influencing the value of slippage and contact stresses, the flank ratio at P-0 correction and P correction, the value of the flank angle, and the module value were analysed. The slippage was analysed at Point B1, which belongs to the beginning of the single tooth engagement area, as well as in Point B2, where the single tooth engagement area ends. Contact stresses were calculated at Point C, which is the pitch point. Their values were referenced to experimentally determined fatigue contact durability σHlim.
THE INFLUENCE OF SURFACE FREE ENERGY
ON TRIBOLOGICAL PROPERTIES OF OXIDE LAYER S
FORMED ON ALUMINIUM ALLOY EN AW-5251
Authors: NIEDŹWIEDŹ Mateusz , BARA Marek , SKONECZNY Władysław
Published: November 2018

This paper presents the influence of the parameters of the formation of oxide layers on the surface free energy
and the tribological properties of these layers. The layers were formed electrochemically on aluminium
alloy EN AW-5251, with variable values of electrolyte temperature and current density. A three-component
electrolyte was used to produce oxide layers. The surface free energy was determined by the droplet deposition
method by measuring the wetting angles, while the van Oss-Chaunhury-Good method was used for the
calculations. Tribological tests were performed on a T-17 tribological tester under conditions of technically
dry friction for reciprocating motion. T7W composite was used as a specimen in tribological tests.
FUNCTION OF THE MENISCI IN THE LOAD TRANSFER WITHIN THE KNEE JOINT
Authors: RYNIEWICZ Andrzej , RYNIEWICZ Anna M. , MACHNIEWICZ Tomasz , BOJKO Łukasz , RYNIEWICZ Wojciech
Published: November 2018

The aim of the study was to conduct strength analysis of a knee joint in order to experimentally determine the destructive fatigue loading under the conditions of cyclic compression. Animal joints were used as the study material. They were periodically subjected to variable axial loading. The degree of joint deformity and damage to articular surfaces and menisci were globally determined after isolation of the joint structures. The application of the variant of axial loading without slip and rolling results in the rupture of the medial meniscus, which is an important biotribological structure. Fatigue testing of the joints allowed for the determination of the parameters of biomechanical extortions, which lead to the loss of normal lubrication conditions and the degradation of the meniscus and cartilage structures on the femoral condyles.
TRIBOLOGICAL TESTS OF NANOCOMPOSITES FOR DIRECT RESTORATION OF TEETH
Authors: RYNIEWICZ Wojciech , HERMAN Mariola , RYNIEWICZ Anna M. , BOJKO Łukasz , PAŁKA Paweł
Published: November 2018

The development of the interphase structure of polymer nanocomposites provides them with tribological properties difficult to obtain in traditional microfiller composites and microhybrid composites. In material solutions, it is preferable to modify the parameters of the material in order to obtain properties that are as close to the hard tissues of the teeth as possible. The aim of the study is to compare the wear resistance of new light-cured nanocomposites and to analyse the surface layer and structure before and after the wear process. Recently developed modern materials were selected for the study. In nanocomposites, G-aenial, G-aenial X FLO, and Essentia, an optimal structure was found in SEM images before and after wear, as well as low resistance to sliding friction and resistance to tribological wear. All tested composites were characterized by suitable properties for clinical applications.
ANALYSIS OF TRIBOLOGICAL PROPERTIES OF SELECTED PTFE-BASED POLYMER COMPOSITES IN A SLIDING INTERACTION WITH ALUMINIUM OXIDE (Al2O3)
Authors: SKONECZNY Władysław , KAPTACZ Sławomir , BARYLSKI Adrian , KMITA Tomasz
Published: November 2018

The paper presents the microstructure and mechanical and tribological properties of polymer composites based on polytetrafluoroethylene (PTFE) intended for use in friction couples where reciprocating motion is performed, e.g., in compressors or actuators. Micromechanical tests carried out using the Oliver-Pharr method showed that the PTFE composite with a 40% bronze content (T8B) had the most advantageous mechanical properties (hardness H, Young’s modulus E). In turn, tribological tests that were conducted using a ballon- disc tester in the linear (reciprocating) motion showed that the polytetrafluoroethylene composite with a mixture of 25% bronze powder and 15% graphite (T4GM) had the lowest tribological wear. The tribological properties of composite T5W with 25% graphite content were not much worse. Despite the most favourable mechanical parameters, the tribological wear of composites T8B and PTFE with glassy carbon (T3Ws) was nearly twice higher due to the absence of grease formed by a graphite filling. The results show that the use of composites containing a bronze-graphite filling improves the service life of lubricant-free friction couples that perform reciprocating motion.
MODELLING OF WEAR UNDER THE CONDITIONS
OF HIGH SLIDING SPEEDS
Authors: SOROKATYI Ruslan , KORGA Sylwester , CHARLAK Michał , KOZERA Ryszard
Published: November 2018

The paper presents a probabilistic model of the wear process of machine elements under the conditions of
high-speed friction using the thermo-kinetic theory of fracture. The definition of model parameters is based
on the probabilistic-physical approach. The model is presented in a discrete form and adapted for using
computer simulation methods that require spatio-temporal sampling of computational models. The analysis of
calculation results shows that the dominant factor that affects the stress-strain state, and therefore the wear of
the tribological system processes, is the rate of change of the friction coefficient from static to dynamic values.
The rate of change in the friction coefficient was proposed as an effectiveness criterion of using methods for
increasing the wear resistance of systems under the conditions of high-speed friction.
IMPACT OF SLIP SPEED ON THE WEAR INTENSITY
OF 38GSA AND HARDOX 500 STEELS
Authors: TARASIUK Wojciech , NAPIÓRKOWSKI Jerzy , LIGIER Krzysztof
Published: November 2018

The study shows the results of experimental tests on the wear intensity of 38GSA and Hardox 500 steels
in combination with a silicate material in relation to the slip speed. In order to reflect the actual working
conditions, the counter sample was cut out of a 1NF class 15 silicate brick. The granulometric composition of
the sand-lime mixture ranges from 0.1 to 5 mm. Slip speeds were selected to be close to the real conditions in
which construction products and aggregates are transported.
LABORATORY STUDIES OF THE INFLUENCE OF THERMAL CYCLING ON ANTI-WEAR PROPERTIES OF COMPOSITES USED IN BIOTRIBOLOGICAL FRICTION PAIRS
Authors: WALCZAK Agata , PIENIAK Daniel , NIEWCZAS Agata M. , GIL Leszek
Published: November 2018

This paper presents the problems associated with changes in resistance to the tribological wear of light-cured polymer matrix ceramic composites (LC PMCCs) used in conservative dentistry and in dental prosthetics (fillings of carious cavities, dental bridges, structural reinforcements of the dental arch). Wear resistance of the surface layer of PMCCs depends on the time of exposure to the conditions of the oral environment, such as alternating temperatures and the exposure to liquids. The aim of the study was to assess changes in the mechanical properties of the surface layer under thermal cycling in liquid. Indentation hardness tests and scratch tests were performed before and after conditioning. Conditioning included 10,000 cycles of step temperature changes (10–70°C). The results of the scratch tests showed that universal composites that had relatively high filler contents were more resistant to scratching than flow type composites with lower filler contents. It was found that cyclic changes in ambient temperature reduced the wear resistance of universal composites but improved the resistance of flow type composites. In addition, in the case of flow type composites, the hardness of the surface layer was also increased.
From the human genome to the epigenome of cancer: the use of high technology in molecular oncology
Authors: Lewandowska Marzena Anna , Żołna Łukasz , Roszkowski Krzysztof , Kowalewski Janusz
Published: November 2018

Fifteen years after the publication of the full sequence of the human genome which revolutionized medicine and biotechnology, profound elucidation of the molecular mechanisms of genetic disorders remains a challenge. National and international institutions conduct a number of research projects in genomics. Some of them are focused on the characterization
of functional elements of the genome (e.g., the Genome Browser database by the ENCODE consortium),
some gather information on polymorphisms (HapMap, The 1000 Genomes Project)
and mutations (The Human Gene Mutation Database), while other are specifically dedicated
to the genomic characterization of cancer (The Cancer Genome Atlas, The Pediatric Cancer
Genome Project). Even though the projects are conducted independently, juxtapositions of
the constantly updated project data may be performed, leading to interesting results. The
genome-wide association studies (GWAS) allowed the identification of millions of SNPs and
short insertions/deletions, as well as thousands of structural variants of polymorphic gene
products. Further data-mining studies allowed the distinction between synonymous and nonsynonymous
SNPs, which became the basis for the epidemiological studies of various types of
genetic disorders. The results of the sequencing of entire genomes and transcriptomes may
be useful in the identification of novel prognostic and predictive markers. High-throughput
technologies are emerging methods in molecular diagnostics, furthermore the correlation
of DNA methylation patterns and gene expression profiles may also provide useful results in
cancer diagnostics.
Polityka obronna Litwy w latach 2014-2018
Authors: Szymański Piotr
Published: November 2018

The annexation of Crimea in 2014 marks the turning point in Lithuania’s defence policy. Previously, Lithuanian armed forces developed expeditionary capabilities in line with NATO’s out-of-area requirements and had to face substantial manning and equipment shortages as a result of the financial crisis. After 2014 clarion call, Lithuania responded with the most comprehensive measures of all the Eastern Flank states to strengthen its military capabilities. Lithuania’s main strategic concerns encompass both the Russian A2/AD bubble in Kaliningrad as well as the development of Russian offensive capabilities in the Baltic Sea region. The Lithuanian strive for security included a big hike in defence spending and a gradual increase in military personnel, with the reinstatement of conscription, faster modernisation of armed forces, development of military infrastructures, investments in combat readiness and an update of military exercises.
This was supplemented by the strengthening of defence co-operation with key partners – both bilaterally and within the NATO framework. Lithuania’s main goal was to convince Allies to establish permanent military presence on its territory in order to strengthen deterrence against Russia. Between the NATO Wales Summit in 2014 and the Warsaw Summit in 2016, Lithuania was focused mainly on a closer military collaboration with the US – a country which then took a leading role in the military reassurance of the Eastern Flank. In Lithuania, the US has traditionally been perceived as the main security provider. The Warsaw Summit constituted a milestone in bolstering the Allied defence posture vis-à-vis Russia, which influenced Lithuania’s defence policy. American rotational company-size units in the Baltic states were subsequently replaced by NATO’s Enhanced Forward Presence, i.e. the deployment of German-led battalion-size battlegroup in Lithuania. Therefore, between 2016 and 2018 Lithuania tried to augment its strong defence ties with US while deepening military integration with Germany. The most significant sign of a closer military co-operation with Germany was the procurement of 88 Boxer infantry fighting vehicles. Recently, Germany has become the biggest supplier of military equipment to the Lithuanian army.
Although Lithuania prefers to develop military co-operation primarily with US and Germany, Poland remains its important orientation point (mainly due to a similar threat perception and Poland’s geographic location). The core dimensions of the Polish-Lithuanian defence collaboration are the strengthening of air defence, including Grom systems deliveries, training of special forces and development of the trilateral brigade (LITPOLUKRBRIG) together with Ukraine.
In the coming years, the ongoing depopulation will remain the biggest internal challenge for the Lithuanian defence policy. Emigration and an ageing society result not only in a decreasing number of citizens reaching the enlistment age, but may also adversely affect the economic situation and - as a consequence - defence expenditure.
Quasi państwa na obszarze poradzieckim – Naddniestrze w rosyjskiej polityce zagranicznej
Authors: Potulski Jakub
Published: November 2018

The main aim of this article is to give an overview of the conflict in a region called Transnistria or Pridnestrovskaya Moldovskaya Respublika (PMR), a quasi-state that has been outside of Moldovan control since 1992. Author focus on historical and emotional aspect of conflict. The turning point of this region’s history was in 1812, when Russia, after the war with Ottoman Turkey annexed part of historic Moldavian territory and named it Bessarabia. During the time, the territory was used as a geostrategic point for Russia’s reaching Black Sea coast. After the World War I Bessarabia become a part of Kingdom of Romania but Soviet Union regarded the area as a territory occupied by Romania. After the World War II the area was formally integrated into the Soviet Union as a Moldavian ASRR. In 1991 during the process of the dissolution of Soviet Union the Moldavian ASRR proclaimed the independence. This proclamation initiated the internal conflict ended with secession of eastern periphery of former Soviet republic. Moscow brought Transnistria under protective umbrella in the international area. The paper will examine the historical roots of the conflict and Russian vision of Transnistria as a part of русский мир.
Uwarunkowania stosunków chińsko-rosyjskich na początku XXI wieku
Authors: Mencel Marian
Published: November 2018

When considering the issue of the latest relationship between the Russian Federation and the People's Republic of China, one attempted to identify them in the article in terms of the political, economic and military range, as well as the involvement of both countries in the aspect of the institutionalised international relations, particularly the traditional areas of influence of both countries, especially in a region of Central Asia. One indicated the intensification of the processes occurring in their relations, and their mutual consistency.
APRENDER NA ESCOLA PARA ALÉM DA SALA DE AULA: COMUNIDADES DE PRÁTICA, PARTICIPAÇÃO PERIFÉRICA LEGÍTIMA E ESPAÇOS DE AFINIDADE NO AMBIENTE ESCOLAR FORMAL
Authors: Roberto Antunes Scherer Júnior Cláudio
Published: November 2018

The formal teaching environment can be a place of various forms of knowledge building. This can be verified in the daily life of any school institution, where the interactions between students are constant and, therefore, the exchanges of knowledge as well. The intention of this article is to problematizeon moments not considered as teaching / learning, extraclass moments that can become important knowledgesource for students' lives. For this, some authors from different areas of knowledge are mobilized, mainly Lave and Wenger (1991) who work with the concept of legitimate peripheral participation and communities of practice, and, Gee (2004) that articulatethe previous ideas to the interconnected context of present through the affinityspaces. The author's personal memories helped to think about some forms of extra-class learning possible in a formal school environment. The challenge of overcoming the hegemony of schooling, as well as the exclusivism of school contents as the only sources of knowledge, to the detriment of learning resulting from human interactions seems to be fundamental.