Journal articles: 'Specific surface bearing'

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Zika, T., I. C. Gebeshuber, F. Buschbeck, G. Preisinger, and M. Gröschl. "Surface analysis on rolling bearings after exposure to defined electric stress." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 223, no. 5 (March 18, 2009): 787–97. http://dx.doi.org/10.1243/13506501jet538.

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This article gives an overview about classical and frequency converter-induced spurious bearing currents in induction machines and discusses typical damage patterns caused by the current passage. To investigate on the electric damage mechanisms, test bearings are operated in a test rig and exposed to specific (classical low-frequency, and high-frequency) bearing currents. The induced damages to the surfaces are analysed visually and with the help of an atomic force microscope, and compared for the different electric regimes applied. Further, the electrically damaged bearing surfaces are characterized by standard roughness parameters. The surface structure observable on certain test bearings shows good correlation to the structure found with a bearing that had failed in the field under similar electric conditions. One of the investigated electric regimes applying high-frequency currents proved capable of generating fluting patterns - as found in real applications - on the test rig. The experiments also indicate that high-frequency bearing currents, although in total dissipating less energy, are more dangerous to a bearing than continuous current flow. The presented method gives a good starting point for further investigation on electric current damage in bearings, especially regarding high-frequency bearing currents, and on bearing/grease lifetime under specific electric regimes.

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Mizobe, Koshiro, Masahiro Takamiya, Takashi Honda, Hitonobu Koike, Edson Costa Santos, Yuji Kashima, and Katsuyuki Kida. "Fourier Transform Infrared Spectroscopy for Wear Debris Adhesion on PEEK Bearing Surface." Applied Mechanics and Materials 307 (February 2013): 372–76. http://dx.doi.org/10.4028/www.scientific.net/amm.307.372.

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Polyetheretherketone (PEEK), a tough semi-crystalline thermoplastic polymer with excellent mechanical properties and polytetrafluoroethylene (PTFE), valued for its low friction coefficient are popular materials used for the production of bearings. In this work, rolling contact fatigue (RCF) tests were performed in order to investigate wear on bearing surfaces by using the Fourier Transform Infrared Spectroscopy (FT-IR). It is reported that PEEK’s specific peak at 1243cm-1was shifted and PEEK’s polymer bearing crystalline content level on wear surface remained unchanged by contact stress or wear debris adhesion.

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Chen, Long, Fei Xing, Yuanzheng Wang, Rui He, Jingming He, Yunwen Xu, Cheng Wang, et al. "Outcome analysis of various bearing surface materials used in total hip replacement." Materials Express 10, no. 3 (March 1, 2020): 301–13. http://dx.doi.org/10.1166/mex.2020.1651.

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Since the first total hip replacement (THR) in 1938 by Philip Wiles, prosthesis materials and THR surgical technologies have developed rapidly. In this review, we use internationally-published research to synthesize a comprehensive analysis of the specific characteristics and clinical outcomes of different bearing surfaces used in THR. Polyethylene, metallic alloys, and ceramic have become the three most commonly used hip prosthesis bearing surfaces after decades of hip implant development. Different bearing surface types have varying characteristics that offer specific benefits and risks of complication. A thorough understanding of the unique properties and possible complications of each type of bearing surface is critical to surgeons tasked with selecting appropriate implant materials for total hip replacement.

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Schüler, Eckhard, and Olaf Berner. "Improvement of Tilting-Pad Journal Bearing Operating Characteristics by Application of Eddy Grooves." Lubricants 9, no. 2 (February 10, 2021): 18. http://dx.doi.org/10.3390/lubricants9020018.

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In high speed, high load fluid-film bearings, the laminar-turbulent flow transition can lead to a considerable reduction of the maximum bearing temperatures, due to a homogenization of the fluid-film temperature in radial direction. Since this phenomenon only occurs significantly in large bearings or at very high sliding speeds, means to achieve the effect at lower speeds have been investigated in the past. This paper shows an experimental investigation of this effect and how it can be used for smaller bearings by optimized eddy grooves, machined into the bearing surface. The investigations were carried out on a Miba journal bearing test rig with Ø120 mm shaft diameter at speeds between 50 m/s–110 m/s and at specific bearing loads up to 4.0 MPa. To investigate the potential of this technology, additional temperature probes were installed at the crucial position directly in the sliding surface of an up-to-date tilting pad journal bearing. The results show that the achieved surface temperature reduction with the optimized eddy grooves is significant and represents a considerable enhancement of bearing load capacity. This increase in performance opens new options for the design of bearings and related turbomachinery applications.

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Mukutadze, M. A., M. V. Novakovich, and N. S. Zadorozhnaya. "Computational Model for Radial Plain Bearing with Non-Circular Bearing Surface Profile and Fusible Coating on Shaft Surface." Journal of Physics: Conference Series 2096, no. 1 (November 1, 2021): 012023. http://dx.doi.org/10.1088/1742-6596/2096/1/012023.

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Abstract The paper presents a study based upon: a Newtonian fluid flow equation (“thin layer”), a continuity equation, and an equation of the molten-profile radius for a shaft coated with a fusible metal alloy; considering a mechanical energy dissipation rate formula, the authors produced an asymptotic and accurate automodel solution for the zero approximation (melting ignored) and first approximation (adjusted for melting) of a radial plain bearing featuring a fusible metal coating and a bearing profile adapted to the specific friction parameters. The paper further presents analytical dependencies describing the molten surface radius, velocity and pressure fields for zero and first approximation. Besides, it determines the key operating parameters of the frictional couple, the bearing capacity, and the friction. It also shows how the parameters arising from the melting of the surface affect the bearing capacity and friction where the bearing surface profile is adapted to the specific conditions of friction.

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Hagemann, Thomas, Huanhuan Ding, Esther Radtke, and Hubert Schwarze. "Operating Behavior of Sliding Planet Gear Bearings for Wind Turbine Gearbox Applications—Part II: Impact of Structure Deformation." Lubricants 9, no. 10 (October 1, 2021): 98. http://dx.doi.org/10.3390/lubricants9100098.

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The use of planetary gear stages intends to increase power density in drive trains of rotating machinery. Due to lightweight requirements on this type of machine elements, structures are comparably flexible while mechanical loads are high. This study investigates the impact of structure deformation on sliding planet gear bearings applied in the planetary stages of wind turbine gearboxes with helical gears. It focuses on three main objectives: (i) development of a procedure for the time-efficient thermo-elasto-hydrodynamic (TEHD) analysis of sliding planet gear bearing; (ii) understanding of the specific deformation characteristics of this application; (iii) investigation of the planet gear bearing’s modified operating behavior, caused by the deformation of the sliding surfaces. Generally, results indicate an improvement of predicted operating conditions by consideration of structure deformation in the bearing analysis for this application. Peak load in the bearing decreases because the loaded proportion of the sliding surface increases. Moreover, tendencies of single design measures, determined for rigid geometries, keep valid but exhibit significantly different magnitudes under consideration of structure deformation. Results show that consideration of structure flexibility is essential for sliding planet gear bearing analysis if quantitative assertions on load distributions, wear phenomena, and interaction of the bearing with other components are required.

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Cahyo, Nur, P. Paryanto, Ariyana Dwiputra Nugraha, Arionmaro Simaremare, Indra Ardhanayudha Aditya, Bara Songka Laktona Siregar, and Mohammad Tauviqirrahman. "Effect of Engineered Roughness on the Performance of Journal Bearings Lubricated by Bingham Plastic Fluid Using Computational Fluid Dynamics (CFD)." Lubricants 10, no. 12 (November 25, 2022): 333. http://dx.doi.org/10.3390/lubricants10120333.

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A journal bearing is a machine element that is used to keep the shaft rotating about its axis. The increasing demand for journal bearing applications in high-speed machines that are efficient and economical has resulted in the need for improvements to the acoustic and tribological performance of journal bearings. In order to improve the tribological and acoustic performance, this study aims to propose a novel journal bearing design by introducing a roughness condition in a specific zone of the stationary bearing surface. In addition, the impact of the application of engineered roughness on the performance of Bingham-plastic-lubricated bearings is investigated in more detail. Considering the effect of cavitation, the analysis was conducted using a 3D computational fluid dynamics (CFD) model of a journal bearing. In comparison with the Reynolds equation—which is inertialess—for lubrication analysis, the use of a 3D CFD model based on Navier–Stokes equations reflects more detailed flow characteristics. Moreover, in this work, variations in the area of surface roughness were employed, resulting in various roughness patterns on the surface of the journal bearing, so that the acoustic and tribological performances of the journal bearing were anticipated to be enhanced. The findings of this study show that under non-Newtonian lubrication of the bearing, the engineered roughness has a strong effect in altering the tribological performance. Furthermore, the well-chosen roughened surface was proven to be more pronounced in enhancing the load support and reducing the friction force. The simulation results also show that using an engineered surface has little effect on the noise of the bearing.

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Pandey, Shashikant, and Muniyappa Amarnath. "Applications of vibro-acoustic measurement and analysis in conjunction with tribological parameters to assess surface fatigue wear developed in the roller-bearing system." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 235, no. 10 (January 8, 2021): 2034–55. http://dx.doi.org/10.1177/1350650120982465.

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Rolling-element bearings are the most commonly used components in all rotating machinery. The variations in the operating conditions such as an increase in the number of operating cycles, load, speed, service temperature, and lubricant degradation result in the development of various defects such as pitting, spalling, scuffing, scoring, etc. The defects that appeared on rolling contact surfaces cause surface deterioration and change in the vibration and sound levels of the bearing system. The present experimental investigations are aimed at assessing the surface fatigue wear that appears on the contact surfaces of roller bearings. The studies considered the estimation of specific film thickness, analysis of surface fatigue wear developed on the rolling-element surfaces, surface roughness analysis, grease degradation analysis using Fourier transform infrared radiation, and vibration and sound signal measurement and analysis. The results obtained from the experimental investigation provide a good correlation between surface wear, vibration, and sound signals with a transition in the lubrication regimes in the Stribeck curve.

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Perumalla, Sateesh Kumar, Amarnath Muniyappa, and Aravindan Sivanandam. "Applications of microwave heat treatment process to enhance the surface properties of bronze and steel materials used in journal bearing." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 10 (January 27, 2020): 2064–76. http://dx.doi.org/10.1177/0954406220902169.

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Journal bearings are important conformal sliding contact machine elements widely used in industrial applications to support cylindrical shafts subjected to radial loads. Wear in journal bearings propagate due to increase in fatigue load cycles, lubricant degradation, misalignment, etc. Hence, it is important to minimize the occurrence of wear in journal bearings by improving their mechanical properties. Microwave heat treatment process is one of the recent developments emerged to improve the surface properties of materials in which energy is directly delivered to the material surface through molecular interaction with the electromagnetic field. In the present work, microwave heat treatment process was used to improve the performance of journal and bearing materials. Further, the microwave-treated journal and bearing specimens were used to conduct performance evaluation experiments under hydrodynamic lubrication regime operating condition. Results highlighted the importance of microwave treatment to reduce wear in both journal and bearing components. A significant reduction in friction coefficient and specific wear rate values were obtained, which resulted in a considerable improvement in the operating performance of the journal bearing system with respect to the increase in fatigue load cycles.

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Sy Truong, Dinh, Byung-Sub Kim, and Jong-Kweon Park. "Thermally affected stiffness matrix of angular contact ball bearings in a high-speed spindle system." Advances in Mechanical Engineering 11, no. 11 (November 2019): 168781401988975. http://dx.doi.org/10.1177/1687814019889753.

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Bearing stiffness directly affects the dynamic characteristics in a high-speed spindle system and plays an important role in terms of manufacturing quality. We developed a new approach for predicting the thermal behavior of a high-speed spindle, calculated the thermal expansion, and generated a bearing stiffness matrix for angular contact ball bearings. The heat convection of spindle housing in air, the balls in lubricant, the spindle shaft in quiescent air, and the bearing inner ring surfaces were determined. Heat sources such as bearing friction, and the heat contributed by the built-in motor, were simulated using an analysis systems (ANSYS) steady-state thermal model. The results were imported into a static ANSYS structural model. Ball thermal expansion was calculated based on changes in the coordinates of nodal points on the ball surface. Finally, a thermally affected bearing stiffness matrix was generated by applying the Newton–Raphson technique. Decreases in the bearing radial, axial, angular, and coupling stiffness values as rotational spindle speed increased were calculated. Also, the stiffness coefficients at a specific speed increased significantly caused by the thermal effects. Finally, for validation, the bearing stiffness was compared to that calculated using an earlier thermal network approach.

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Nazin, Vladimir. "Revealing the influence of structural and operational parameters of a wooden hydrostatic bearing on its performance." Eastern-European Journal of Enterprise Technologies 6, no. 1 (120) (December 30, 2022): 25–32. http://dx.doi.org/10.15587/1729-4061.2022.269703.

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Wooden bearings, lubricated with water and other low-viscosity lubricants, have been used for centuries. In steamship engines, turbines of hydroelectric power plants and propellers of submarines, it is proposed to use wooden hydrostatic bearings, which are guaranteed to provide liquid friction and have high reliability. The object of this study is hydrostatic and thermal processes in sliding supports with wooden hydrostatic bearings. The influence of the design and operational parameters of a wooden hydrostatic bearing on its performance was tackled. Theoretical dependences are given, making it possible to determine the bearing capacity and temperature increase in the hydrostatic bearing. Quantitative values of specific pressures on the working surface of the bearing and an increase in the temperature of the working fluid due to friction and pumping losses were established. It was found that the specific pressures of the liquid do not exceed the tensile strength of the bearing material. The reduction in load capacity due to an increase in the temperature of the working fluid was 10.95 %, owing to the small change in the temperature of the working fluid in hydrostatic bearings. The results of the study make it possible to establish the permissible boundaries for the purpose of the design and operational parameters of the hydrostatic bearing ensuring its operability. For the effective use of hydrostatic wooden bearings at the listed facilities, it is necessary to have a system for supplying lubricant to the bearing under high pressure. The system should include filters to clean the lubricant from impurities. The theoretical dependences built allow designers of hydrostatic bearings to use them in practical calculations

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Razzeca, Kristin J., Stevens Y. Kim, and Robert V. Rouse. "Identification and surface phenotypic characterization of phosphorylcholine-specific idiotype-bearing T cells." Cellular Immunology 112, no. 2 (April 1988): 442–48. http://dx.doi.org/10.1016/0008-8749(88)90314-0.

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Akhter, R., A. Hussain, W. A. Farooq, and M. Aslam. "Laser Surface Hardening of GCr15 Bearing Steel Ring." Key Engineering Materials 442 (June 2010): 130–36. http://dx.doi.org/10.4028/www.scientific.net/kem.442.130.

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Surface hardening of GCr15 bearing steel ring was carried out using CW CO2 laser. The laser power used was in the range of 300 to 500 Watts. A rectangular beam shape was used to cover the area to be hardened. A three fold increase in the hardness of the transformed zone was achieved. The depth of hardness attained was around 1mm. The depth and width of the laser treated zone were studied as function of laser power and working speed for specific spot size. The microstructure of the transformed zone is also discussed. Subzero cooling technique was applied to convert the retained austenite to martensite.

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Zhang, Yongbin. "BOUNDARY SLIPPAGE FOR IMPROVING THE LOAD AND FRICTION PERFORMANCE OF A STEP BEARING." Transactions of the Canadian Society for Mechanical Engineering 34, no. 3-4 (September 2010): 373–87. http://dx.doi.org/10.1139/tcsme-2010-0022.

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The present paper proposes a new type of step bearing by specifically modifying the interfacial condition between the fluid film and the bearing surface and introducing the boundary slippage at those interfaces. Analysis for the load-carrying capacity and friction coefficient is presented for this kind of bearing. The comparison of the obtained analytical results with the conventional (no-slippage) step bearing results shows that modifying the interfacial condition and introducing the boundary slippage at the specific bearing surfaces can significantly increase the load-carrying capacity and reduce the friction coefficient of a step bearing. Design guideline, the load-carrying capacity and the friction coefficient are also presented for this bearing at optimum condition which reaches the maximum load-carrying capacity.

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Wang, Jing, Li Ying Yang, Shou Ren Wang, Guang Ji Xue, and Chang Xiu Zhou. "Stress Distribution Behavior of Spherical Plain Bearing Fabricated by TiAl-Based Composite Materials Based on the Finite Element Analysis." Advanced Materials Research 1061-1062 (December 2014): 649–52. http://dx.doi.org/10.4028/www.scientific.net/amr.1061-1062.649.

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Spherical plain bearing is a sliding bearing have a spherical contact surface,it can bear larger load and automatically adjusted to the self-alignin. TiAl-based composite material is a material that be used to lightweight spherical plain bearing. The Simulation used the finite element software Ansys for the bearing’s static analysis.The material of outer ring using normal bearing steel, one group used the TiAl-based composite materials as the material of the inner ring, Another group the inner ring material is bearing steel 9Cr18. The law of the stress and strain produced by the two groups is consistent,the deformation of the composite materials is bigger under the same load, its elasticity modulus and density is smaller compared to the ordinary bearing steel,the composite material has the advantages of high specific strength especially in the occasions have strict requirements of the bearing weight.

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Ivanschikov, Yuriy, Vasiliy Skovorodin, Yuriy Dobrohotov, Roman Andreev, Aleksandr Vasil'ev, and Ayrat Valiev. "RESEARCH OF THE WEAR MECHANISM OF BEARING SEATS OF AUTOMOTOR-TRACTOR TRANSMISSIONS." Vestnik of Kazan State Agrarian University 16, no. 4 (February 15, 2021): 71–79. http://dx.doi.org/10.12737/2073-0462-2021-71-79.

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A significant number (up to 25%) of failures of automotive transmissions are associated with a loss of rigidity in the rolling bearings. One of the main reasons for the loss of stiffness in rolling bearings is a violation of the tightness of the bearing on the shaft and in the housing due to fretting corrosion. The paper presents the results of a study of the causes of fretting corrosion in bearing fits and the patterns of its development. The conditions promoting the occurrence of the fretting process are determined and the factors characterizing the nature and intensity of destruction of contacting surfaces during fretting corrosion are established. It was also found that the greatest influence on the occurrence and course of the fretting process is exerted by the specific load on the contact surface, the duration and frequency of its application, and the amplitude of the relative slip of the contacting surfaces. Analytical expressions for calculating the actual values of the listed factors of the fretting process in the coupling of the rolling bearing with the shaft are determined by the calculation method, and a mathematical model of its destruction is proposed. For the practical implementation of the described mechanism of destruction of the rolling bearing landing on the shaft as a result of fretting corrosion, an algorithm and a program have been developed to determine the limiting state of the bearing landings of automotive transmissions. Subsequent laboratory tests confirmed the adequacy of the proposed model. As an example, the results of modeling the limiting state of the rolling bearing of the intermediate shaft of the gearbox of the K-700A tractor and the ball bearing 313 are given. It is revealed that the main role in reducing the intensity of the fretting process, along with the hardness of the shaft, is played by the roughness of its seating surface. In particular, a decrease in the roughness parameters from Ra = 2.0 µm to Ra = 0.5 µm at the same hardness HRC48 and an interference fit in N = 24 µm leads to an increase in the joint resource by 1.5 times

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Gao, L. M., Q. E. Meng, F. Liu, J. Fisher, and Z. M. Jin. "The effect of aspherical geometry and surface texturing on the elastohydrodynamic lubrication of metal-on-metal hip prostheses under physiological loading and motions." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 224, no. 12 (June 23, 2010): 2627–36. http://dx.doi.org/10.1243/09544062jmes2193.

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As an alternative material combination, metal-on-metal (MOM) hip replacement has attracted a revived interest due to its very low wear rates. In this article, an elastohydrodynamic lubrication analysis is performed for an MOM hip replacement with specific geometrical designs: a macro Alpharabola geometry of the cup bearing surface and micro-dimples on the head surface. The corresponding numerical methodology is presented and full numerical solutions are obtained. The effect of the macro- and micro-geometrical designs on the lubrication performance is investigated, under both simplified and physiological walking conditions. The real physiological loading and motion conditions are important to be considered when optimizing the conformity-associated geometry of hip bearings. The Alpharabola geometry of cup bearing surface is found to significantly improve the lubricating film thickness and reduce hydrodynamic pressure of MOM hip implants, when the Alpharabola minimum radius is aligned with the loading direction. Dimpled surface texturing has an adverse effect in a fluid film lubrication regime under the conditions considered in this study.

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Xue, Jifeng, Shigeshi Fuchida, Sana Ishida, and Chiharu Tokoro. "Insight on Exogenous Calcium/Magnesium in Weakening Pyrite Floatability with Prolonged Pre-Oxidation: Localized and Concomitant Secondary Minerals and Their Depression Characteristics." Minerals 12, no. 2 (January 20, 2022): 115. http://dx.doi.org/10.3390/min12020115.

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In this study, we investigated the localized and concomitant precipitation of calcium (Ca)/magnesium (Mg)-bearing species and iron oxides/oxyhydroxides, and their depression characteristics to the pyrite floatability in flotation process at pH 9 and pH 10.5 with prolonged pre-oxidation. Contrary to the depression characteristics at pH 9, the incipient (within aeration times of 30 min) depression of pyrite floatability in Ca/Mg-bearing solutions was more obvious at pH 10.5, while the subsequent decline was only slightly when the pre-oxidation time was expanded to 120 min and 360 min. The competitive adsorption among Ca/Mg-bearing species and potassium amyl xanthate (PAX, C6H11OS2K, collector) at specific sites onto the pyrite surface was demonstrated by the regularly decreased zeta potential of the pyrite surface pretreated in Ca/Mg-bearing solutions. Further scanning electron microscopy-energy dispersive spectrometry demonstrated the concomitant secondary Ca/Mg/Fe-bearing precipitates on the pyrite surface. X-Ray photoelectron spectroscopy suggested strong reprecipitation of iron oxides/oxyhydroxides on the pyrite surface via acid–base complexation among Ca/Mg hydroxy species and iron hydroxy species. Incipient occupation efficiency of specific reaction sites by Ca/Mg-bearing species, which were mainly controlled by the metastable distribution of Ca/Mg hydroxy species and their electrostatic affinity with pyrite surface, was the crucial factor that influenced the competitive adsorption of xanthate and pyrite floatability. More obvious incipient depression at pH 10.5 rather than at pH 9 contributed to more effective Ca/Mg-bearing species and their higher affinity to pyrite surface at pH 10.5. The localized and concomitant precipitation of secondary Ca/Mg/Fe-bearing species leads to a slightly increased hydrophilic coverage upon the pyrite surface, thus a slowly decreased pyrite floatability with increasing pre-oxidation time.

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Wang, Chun E., and Jian Cheng Fang. "Analysis of Specific Load Capacity of Radial Hybrid Magnetic Bearing." Advanced Materials Research 668 (March 2013): 485–89. http://dx.doi.org/10.4028/www.scientific.net/amr.668.485.

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This paper proposes a method based on vector calculation of flux density to evaluate the specific load capacity (SLC) of radial hybrid magnetic bearing (RHMB). The vector sum of the flux densities generated by the permanent magnet and the control current is calculated in this method, and then the functional expression of the SLC is built up via the flux densities. The influence of outer rotor diameter, fraction of circumferential rotor surface covered by poles and the length of the air gap are analyzed. It turns out that the SLC decreases with the maximum force of the bearing, and increases first and then decreases with the increase of pole area and length of the air gap. The maximum attainable SLC for RHMB of all sizes does not vary substantially from 23:1. The results of the analysis provide basis for the prediction of volume and mass for the RHMB in application.

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Li, Y., C. Zhang, T. R. Kurfess, S. Danyluk, and S. Y. Liang. "Diagnostics and prognostics of a single surface defect on roller bearings." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 214, no. 9 (September 1, 2000): 1173–85. http://dx.doi.org/10.1243/0954406001523614.

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Bearing condition monitoring has been the focus of a wide range of studies over the past years. Current monitoring techniques that focus on the identification of faults present in a bearing have various limitations. Typically they are applicable only under well-defined, specific and pre-calibrated operating conditions, thereby preventing continuous monitoring of a system operating in a variant environment. They are often limited in damage severityestimation and prognostic capability. This, in turn, prevents the development of optimal maintenance scheduling in favour of overall system safety and productivity. Research presented in this paper has yielded results that have extended bearing diagnostics and prognostics to address these limitations and to achieveoptimal machinery maintenance scheduling. This paper discusses the current research status on the development of a new signal processing method with noise cancellation capability to provide early defect detection, the establishment of a diagnostic model to estimate bearing defect severity under variant conditions and the formulation of an adaptively tuned defect propagation model to track thetime-variant nature of defect growth for the forecasting of bearing remaining utility.

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Kasarda, M. E. F., P. E. Allaire, P. M. Norris, C. Mastrangelo, and E. H. Maslen. "Experimentally Determined Rotor Power Losses in Homopolar and Heteropolar Magnetic Bearings." Journal of Engineering for Gas Turbines and Power 121, no. 4 (October 1, 1999): 697–702. http://dx.doi.org/10.1115/1.2818529.

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The identification of parameters that dictate the magnitude of rotor power losses in radial magnetic bearings is very important for many applications. Low loss performance of magnetic bearings in aerospace equipment such as jet engines and flywheel energy storage systems is especially critical. Two basic magnetic bearing designs are employed in industrial practice today: the homopolar design, where the flux paths are of a mixed radial/axial orientation, and the heteropolar design, where the flux paths are primarily radial in nature. The stator geometry and flux path of a specific bearing can have a significant effect on the rotor losses. This paper describes the detailed measurement of rotor losses for experimentally comparable homopolar and heteropolar designs. The two test bearing configurations are identical except for geometric features that determine the direction of the flux path. Both test bearing designs have the same air gap length, tip clearance ratio, surface area under the poles, and bias flux levels. An experimental test apparatus was used where run down tests were performed on a test rotor with both bearing designs to measure power losses. Numerous test runs where made for each bearing configuration by running multiple levels of flux density. The components of the overall measured power loss, due to hysteresis, eddy currents, and windage, were determined based on theoretical expressions for power loss. It was found that the homopolar bearing had significantly lower power losses than the heteropolar bearing.

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Kane, K. P., and M. F. Mescher. "Antigen recognition by T cells. Quantitative effects of augmentation by antibodies providing accessory interactions." Journal of Immunology 144, no. 3 (February 1, 1990): 824–29. http://dx.doi.org/10.4049/jimmunol.144.3.824.

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Abstract Although engagement of the TCR via antibody can be sufficient to trigger T cells, responses to Ag-bearing cells require additional "accessory" interactions in many cases. A method has been developed which allows preparation of surfaces bearing both purified class I alloantigen and coimmobilized antibodies. With this approach, it is possible to mimic such "accessory" interactions and to examine their quantitative effects on triggering via TCR-Ag interaction. Experiments are described which use this approach to examine triggering of degranulation by cloned, allogeneic CTL lines. Coimmobilization of antibodies specific for any of a variety of CTL surface proteins, including CD8, class I MHC proteins, CD45 (T200) and Thy-1, had the effect of decreasing the critical threshold density of Ag necessary to trigger responses, and decreasing by an order of magnitude the density required to stimulate a half-maximal response. Furthermore, in comparison with the 30-min lag seen with Ag alone, response was initiated immediately when an antibody specific for a CTL surface component was present. These results are consistent with the hypothesis that any CTL surface molecule having sufficient affinity for a component of the target surface can contribute to activation via the Ag-specific TCR; and at low Ag density could determine whether any response occurs.

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Cui, Yu Qing, Zhong Wei Yin, and Hu Lin Li. "Influence of tension in T300/epoxy prepreg winding process on the performance of the bearing composites." Journal of Reinforced Plastics and Composites 36, no. 15 (April 13, 2017): 1099–115. http://dx.doi.org/10.1177/0731684417702750.

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In recent years, composite bearings are increasingly employed in marine and heavy load situations due to the specific properties of composites. However, for the tape winding composite bearings, the tension in process has not been studied in depth. In this study, a device was manufactured to apply tension to the process and the prepreg tape was T300/epoxy. Specimens with different tension values were selected for the experiment and the autoclave technology was applied to the curing process. Then, the appearance image and roundness of the bearing composites were acquired. Meanwhile, physical and mechanical properties of the specimen as well as the residual stress were measured. The experimental results show that the influence of tension in winding process on bearing composites is significant and the optimum tension can be defined. Subsequently, the article analyzes the function of the tension and it is concluded that the wrinkles and waves on the surface of the T300/epoxy bearing composites can be eliminated using proper method and the optimum tension should be determined through testing and experiment.

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Froscher, B. G., and N. R. Klinman. "Strain-specific silencing of a predominant antidextran clonotype family." Journal of Experimental Medicine 162, no. 5 (November 1, 1985): 1620–33. http://dx.doi.org/10.1084/jem.162.5.1620.

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The immune response to dextran is characterized by marked phenotypic differences among murine strains. In particular, Igha strains, as opposed to strains of other Igh haplotypes, respond relatively vigorously to dextran B1355 fraction S (DEX), producing predominantly antibodies bearing the lambda light chain, and specific for the alpha(1----3) glucose linkage. We have investigated this disparity in BALB/c (Igha) vs. C.B20 (Ighb) mice at the individual precursor cell level. Consistent with previous findings (7-9, 35, 40, 42, 43), there was a 10-fold higher frequency of lambda-bearing splenic B cells specific for the alpha(1----3) linkage in Igha mice. As with previously studied (25-27) predominant specificities, the origin of this high frequency of lambda-bearing alpha(1----3) DEX-specific B cells appears to be a reflection of a high expression of this specificity in surface Ig (sIg)-negative cells emerging from the bone marrow generative cell pool. Surprisingly, although C.B20 mice (Ighb) have a low frequency of lambda-bearing alpha(1----3) DEX-specific B cells in their mature primary splenic population, the frequency of precursor cells of this clonotype in their sIg- bone marrow cell population is equivalent to that of BALB/c sIg- cells. These cells could only be stimulated in allotype allogeneic (Igha), as opposed to allotype syngeneic (Ighb), carrier-primed irradiated recipients. This finding was confirmed by the finding that a high proportion of antidextran hybridoma cell lines derived from C.B20 bone marrow cells produced lambda-bearing alpha(1----3) DEX-specific antibodies that were IdX+. These findings have led us to conclude that the well-established phenotypic difference between Igha and Ighb mice with respect to the expression of lambda-bearing alpha(1----3) DEX-specific antibody responses is not, as previously assumed, the result of an inability of Ighb mice to generate B cells of this clonotype, but rather, is the product of environmental, possibly antiidiotypic, silencing of cells of this clonotype as they mature in Ighb mice.

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25

Trial, J., and B. W. McIntyre. "Suppressor cell clones specific for ultraviolet radiation-induced tumors. Function and surface proteins." Journal of Immunology 145, no. 7 (October 1, 1990): 2044–49. http://dx.doi.org/10.4049/jimmunol.145.7.2044.

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Abstract Lymphocytes were cloned from animals bearing UV-induced skin tumors. These cells were I-J+, CD4-, CD8-, and had become growth factor independent. Extracts, but not supernatants, of these clones suppressed primary immune reactions in vitro against UV-induced tumors, but not methylcholanthrene-induced tumors. The cells therefore had the functional characteristics of afferent suppressor T cells directed against a common Ag on UV-induced tumors. Surface iodination of the clones revealed an extremely low level expression of molecules that might be TCR or related molecules.

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Li, Min, Bernhard Karpuschewski, and Oltmann Riemer. "High-efficiency nano polishing of steel materials." Nanotechnology Reviews 10, no. 1 (January 1, 2021): 1329–38. http://dx.doi.org/10.1515/ntrev-2021-0092.

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Abstract The application of a specific rheological polishing slurry is proposed first for high-efficiency machining of steel materials to achieve high-quality ultraprecision finished surfaces. The rheology of the polishing slurry was explored to show that the non-Newtonian medium with certain parameters of content components exhibits shear-thickening behavior. Then the new high-efficiency nano polishing approach is applied to process spherical surfaces of bearing steel. Several controllable parameters such as shear rheology, abrasive data, rotational speed, and processing time are experimentally investigated in this polishing process. A special finding is that the surface roughness and material removal rate can increase simultaneously when a small abrasive size is applied due to the thickening mechanism during the shearing flow of slurries. Excessive abrasives can decrease surface quality due to the uneven agglomeration of particles scratching the surface. Under optimized conditions, a high-accuracy spherical bearing steel surface with a roughness of 12.6 nm and roundness of 5.3 μm was achieved after a processing time of 2.5 h. Thus, a potential ultraprecision machining method for target materials is obtained in this study.

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27

Hrițuc, Adelina, Laurențiu Slătineanu, Oana Dodun, Gheorghe Nagîț, Margareta Coteață, Marius Andrei Boca, and Vasile Ermolai. "Sustainable Manufacture of Bearing Bushing Parts." Sustainability 13, no. 19 (September 28, 2021): 10777. http://dx.doi.org/10.3390/su131910777.

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Bearing bushing parts are used to support other rotating moving parts. When these bearing bushings are made of bronze, their inner cylindrical surfaces can be finished by turning. The problem addressed in this paper was that of identifying an alternative for finishing by turning the inner cylindrical surfaces of bearing bushing parts by taking into account the specific sustainability requirements. Three alternatives for finishing turning the inner cylindrical surfaces of bearing bushings have been identified. The selection of the alternative that ensures the highest probability that the diameter of the machined surface is included in the prescribed tolerance field was made first by using the second axiom of the axiomatic design. It was thus observed that for the initial turning alternative, the probability of success assessed by using a normal distribution is 77.2%, while for the third alternative, which will correspond to a Maxwell–Boltzmann distribution, the probability of success is 92.1%. A more detailed analysis was performed using the analytic hierarchy process method, taking into account distinct criteria for assessing sustainability. The criteria for evaluating the sustainability of a cutting processing process were identified using principles from the systemic analysis. The application of the analytic hierarchy process method facilitated the approach of some detailed aspects of the sustainability of the alternatives proposed for finishing by turning the inner cylindrical surfaces of bearing bushings, including by taking into account economic, social, and environmental protection requirements.

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Cavenett, Sally, Edward Ko Ko Aung, Sarahlouise White, and Judith Streak. "The effectiveness of total surface bearing compared to specific surface bearing prosthetic socket design on health outcomes of adults with a trans-tibial amputation: A systematic review." JBI Database of Systematic Reviews and Implementation Reports 10, Supplement (2012): 1–13. http://dx.doi.org/10.11124/01938924-201210561-00008.

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Cavenett, Sally, Edward Ko Ko Aung, Sarahlouise White, and Judith Streak. "The effectiveness of total surface bearing compared to specific surface bearing prosthetic socket design on health outcomes of adults with a trans-tibial amputation: A systematic review." JBI Library of Systematic Reviews 10, Supplement (2012): 1–13. http://dx.doi.org/10.11124/jbisrir-2012-256.

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30

Cavenett, Sally, Sarahlouise White, and Judith Streak Gomersall. "The effectiveness of total surface bearing compared to specific surface bearing prosthetic socket design on health outcomes of adults with a trans-tibial amputation: a systematic review." JBI Database of Systematic Reviews and Implementation Reports 12, no. 4 (April 2014): 233–318. http://dx.doi.org/10.11124/jbisrir-2014-1283.

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31

Nιder, Zoltαn, Kαroly Vαradi, and Klaus Friedrich. "Quantitative Evaluation of Wear Grooves in a Fine Particulate Reinforced, Soft Polymer Coating System by Laser Profilometry and Computer Aided Scratch Analysis." Advanced Composites Letters 9, no. 5 (September 2000): 096369350000900. http://dx.doi.org/10.1177/096369350000900501.

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After certain periods of practical application, particulate reinforced polymer coated surfaces frequently contain many grooves due to a scratching contact with any abrasive counterparts. To characterise these scratch patterns a software package (SCRATCH) has been developed using digitised surface roughness data from a laser profilometer. The SCRATCH system identifies individual scratches by representing their locations (using a slicing technique) and specifies scalar parameters (such as the specific scratch area or mid-tangent of the bearing area curve). In this way, the magnitude of the scratch damage can be identified following an approximate technique. This is demonstrated here for wear grooves in a polymer coating system subjected to a particular scratch test. But the method can also be applied to other engineering surfaces, e.g. for wear evaluation of composite bearings, seals and other sliding composite elements.

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32

DeLuca, Dominick, Janet M. Decker, and John J. Marchalonis. "Surface expression and partial characterization of an arsonate hapten-specific idiotype-bearing T-cell receptor." Cellular Immunology 90, no. 2 (February 1985): 514–30. http://dx.doi.org/10.1016/0008-8749(85)90216-3.

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33

Scully, Natalie F., and Barry D. Shur. "Stage-specific increase in cell surface galactosyltransferase activity during spermatogenesis in mice bearing t alleles." Developmental Biology 125, no. 1 (January 1988): 195–99. http://dx.doi.org/10.1016/0012-1606(88)90072-3.

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34

Arora, Sandeep K., Rohit Sharma, Gagandeep Kaur, Preeti Bhoria, Maryada Sharma, and Manni Luthra-Guptasarma. "Towards an indirect screening technique facilitating detection of cellular populations bearing specific cell surface markers." Biotechnology Progress 26, no. 6 (September 27, 2010): 1544–50. http://dx.doi.org/10.1002/btpr.489.

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35

Mazzucchelli, Luca, James B. Burritt, Algirdas J. Jesaitis, Asma Nusrat, Tony W. Liang, Andrew T. Gewirtz, Frederick J. Schnell, and Charles A. Parkos. "Cell-Specific Peptide Binding by Human Neutrophils." Blood 93, no. 5 (March 1, 1999): 1738–48. http://dx.doi.org/10.1182/blood.v93.5.1738.

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Abstract Analysis of peptide binding to human neutrophils (PMN) using phage display techniques has revealed cell-specific motifs reactive with the PMN surface. Phage libraries displaying either linear 9-mer or cyclic 10-mer and 6-mer peptides were incubated with normal human neutrophils followed by elution of bound phage with low pH (pH 2.2) and non-ionic detergent. Three rounds of selection generated several related peptide sequences that bound with high avidity to PMN. Using the linear 9-mer library, PMN-binding phage expressed peptides with the motif (G/A)PNLTGRW. The binding of phage bearing this motif was highly specific since no binding was observed on lymphocytes, fibroblasts, epithelial, or endothelial cells. Functional assays revealed that phage bearing the sequence FGPNLTGRW induced a pertussis toxin-sensitive increase in PMN cytosolic calcium analogous to that observed with Gi coupled receptors. Other prominent motifs identified included phage bearing the consensus DLXTSK(M/L)X(V/I/L), where X represents a non-conserved position. Phage with this motif bound exclusively to a sub population of human PMN that comprised approximately 50% of the total and did not elicit a calcium response. The binding of such phage to PMN was prevented by co-incubation with competing peptides displaying identical or similar sequences (IC50 range from 0.6 μmol/L to 50 μmol/L for DLXTSK and GPNLTG, respectively). We speculate that these techniques will be useful in identifying functional cell-specific binding motifs and contribute to the development of new therapeutic and diagnostic strategies in human disease.

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36

Mazzucchelli, Luca, James B. Burritt, Algirdas J. Jesaitis, Asma Nusrat, Tony W. Liang, Andrew T. Gewirtz, Frederick J. Schnell, and Charles A. Parkos. "Cell-Specific Peptide Binding by Human Neutrophils." Blood 93, no. 5 (March 1, 1999): 1738–48. http://dx.doi.org/10.1182/blood.v93.5.1738.405a18_1738_1748.

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Analysis of peptide binding to human neutrophils (PMN) using phage display techniques has revealed cell-specific motifs reactive with the PMN surface. Phage libraries displaying either linear 9-mer or cyclic 10-mer and 6-mer peptides were incubated with normal human neutrophils followed by elution of bound phage with low pH (pH 2.2) and non-ionic detergent. Three rounds of selection generated several related peptide sequences that bound with high avidity to PMN. Using the linear 9-mer library, PMN-binding phage expressed peptides with the motif (G/A)PNLTGRW. The binding of phage bearing this motif was highly specific since no binding was observed on lymphocytes, fibroblasts, epithelial, or endothelial cells. Functional assays revealed that phage bearing the sequence FGPNLTGRW induced a pertussis toxin-sensitive increase in PMN cytosolic calcium analogous to that observed with Gi coupled receptors. Other prominent motifs identified included phage bearing the consensus DLXTSK(M/L)X(V/I/L), where X represents a non-conserved position. Phage with this motif bound exclusively to a sub population of human PMN that comprised approximately 50% of the total and did not elicit a calcium response. The binding of such phage to PMN was prevented by co-incubation with competing peptides displaying identical or similar sequences (IC50 range from 0.6 μmol/L to 50 μmol/L for DLXTSK and GPNLTG, respectively). We speculate that these techniques will be useful in identifying functional cell-specific binding motifs and contribute to the development of new therapeutic and diagnostic strategies in human disease.

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37

Tibbits, Patrick. "An Alternative Mechanism for Generation of Spherical Debris Particles on Bearing Raceway Spalls." Microscopy Today 10, no. 1 (February 2002): 21. http://dx.doi.org/10.1017/s155192950005046x.

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Spherical debris particles in spalled areas of bearing raceways have been attributed to motions of the crack faces during spall generation. This note suggests an alternative generation mechanism for the particles.Figure 1, from Failure Atlas for Hertz Contact Machine Elements, shows a spherical debris particle lying on the spalled surface of a bearing raceway. The atlas characterizes the spheroids as characteristic of spalling fatigue, and attributes the spheroids to alternating micro-motions between crack faces, but qualifies by saying that the specific mechanism of their generation is not understood. The spheroid measures about 50 microns and consists of bearing steel, oxidized at the surface.

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38

Schöning, H., M. Kadanik, M. Reich, S. Petersen, and O. Kessler. "Challenges of Numerical Simulation Models for Induction Surface Hardening of Large Bearing Rings." HTM Journal of Heat Treatment and Materials 77, no. 5 (October 1, 2022): 319–35. http://dx.doi.org/10.1515/htm-2022-1013.

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Abstract Induction hardening of large bearing rings is a very challenging procedure due to the complex physical processes and their interactions, which need to be properly controlled to produce components meeting the imposed requirements of e.g. wind turbines. The different process parameters significantly alter the resulting microstructures and properties of such a bearing ring. The evolution of numerical simulations in the last decades allows the modelling of processes with a growing complexity. In this work, the challenges of a simulation model for induction surface hardening are shown and discussed. Besides the theoretical background of the interacting physical fields and a brief note about available software packages, the paper focusses on the elaboration of a necessary material database and on the specific problems of induction scan hardening processes for large bearing rings.

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39

Walton, J. F., and H. Hesmat. "Application of Foil Bearings to Turbomachinery Including Vertical Operation." Journal of Engineering for Gas Turbines and Power 124, no. 4 (September 24, 2002): 1032–41. http://dx.doi.org/10.1115/1.1392986.

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A review is made of the function of compliant surface bearings in serving the needs of modern turbomachinery. This service extends over a wide spectrum of severe operational and environmental conditions such as extreme low and high temperatures, speeds over 100,000 rpm, and the use of cryogenics as lubricants. The importance of using appropriate simulators that duplicate the actual equipment in evaluating the application of compliant bearings is demonstrated via two specific examples; one, a simulator to evaluate bearings for an air cycle machine and another for an advanced cryogenic device. In view of the known difficulties in using hydrodynamic bearings in vertical machines a new preloaded compliant journal bearing design is offered which performs as well with a vertically mounted shaft as it does in horizontal operation. In terms of the location of the first two rigid-body criticals, the test data show the compliant bearing’s vertical operation to be at most 15 percent lower than for the horizontal case, whereas the maximum vibrational amplitude stayed the same for both modes of operation. This new class of hydrodynamic compliant surface journal bearings now makes possible development of oil-free machines capable of all attitude operation, such as aircraft gas turbine engines undergoing severe pitch maneuvers or machines that must be operated vertically due to space constraints.

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40

Dutta, M., R. Bandyopadhyay, and M. K. Basu. "Neoglycosylated liposomes as efficient ligands for the evaluation of specific sugar receptors on macrophages in health and in experimental leishmaniasis." Parasitology 109, no. 2 (August 1994): 139–47. http://dx.doi.org/10.1017/s0031182000076253.

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SUMMARYReceptors interacting with terminal sugars as ligands are involved in the binding of Leishmania donovani promastigotes to the macrophage surface and their subsequent internalization. Mannose and glucose are specifically involved in the binding process. Decreased binding occurs to macrophages already infected with L. donovani either in vivo or in vitro. When mannose- or glucose-bearing liposomes are used as ligands the binding shows similar trends and the percentage inhibition of binding with mannose-bearing liposomes increases when compared to that for the glucose-bearing ones. The decreased binding of the ligand seems to be due to a decrease in the number of receptors after infection. The affinity of the ligands for the binding sites either on the normal macrophages or on the infected macrophages apparently remains the same. The results based on the incorporation of [3H]phenyl alanine and supported by the binding of glycosylated liposomes to both infected and non-infected macrophages suggest that protein synthesis, in general, is suppressed in L. donovani infected macrophages thus affecting also mannose/glucose receptor protein synthesis, resulting in fewer receptors on the macrophage surface.

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41

Zhang, Yu, Guoding Chen, and Lin Wang. "Effects of thermal and elastic deformations on lubricating properties of the textured journal bearing." Advances in Mechanical Engineering 11, no. 10 (October 2019): 168781401988379. http://dx.doi.org/10.1177/1687814019883790.

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Hydrodynamic journal bearing is an important part of rotary machine and faces many challenges such as high rotating speed, heavy specific pressure, and large temperature rise with the development of industry. These challenges lead to notable thermal and elastic deformations of the journal bearing. Surface texture has been proved to be a valid method to promote bearing lubricating properties. However, effects of thermal and elastic deformations on lubricating properties of the textured journal bearing have not been clearly analyzed. Based on this, the article presents a method to transform thermal–structural–fluid interaction into thermal–structural interaction and thermal–fluid interaction based on textured journal bearing model. Cavitation and temperature-viscosity effects are also considered. Based on this method, action mechanisms of surface texture on lubricating properties are discussed considering elastic and thermal deformations, and effects of elastic and thermal deformations on the textured journal bearing are also investigated. The results show that the load carrying capacity and the maximum oil film pressure of the textured journal bearing both increase when elastic and thermal deformations are considered. Optimal texture parameters can enhance the backflow effect in dimples and restraint cavitation phenomenon in the oil film rupture region. Meanwhile, inertial and cavitation effects caused by surface texture have significant effects on elastic and thermal deformations of the journal bearing.

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42

Liu, Xiaochu, Xiujie Chen, Zhongwei Liang, Tao Zou, Zhaoyang Liu, Jinrui Xiao, Dongwei Li, and Diaodiao Yu. "The Tribological Properties of 30CrMnSiA Bearing Steels Treated by the Strengthening Grinding Process under Lubrication Wear." Materials 15, no. 20 (October 21, 2022): 7380. http://dx.doi.org/10.3390/ma15207380.

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This study used the strengthening grinding process (SGP) to treat the surface of 30CrMnSiA bearing steels. The effect of the jet angle of SGP on the tribological properties of 30CrMnSiA bearing steels under lubrication was investigated. The principle of enhancing wear resistance of 30CrMnSiA bearing steel ascribed to SGP was discussed in detail. The results showed that the lubrication properties and surface hardness of the 30CrMnSiA steels were enhanced due to the formation of numerous microscale microscope oil pockets on the surface layer and the grain refinement of the surface microstructures, resulting in a significant improvement in wear resistance. With the jet angle of SGP increased from 0° to 90°, the friction coefficient, the wear volume, and the specific wear rate were exhibited to reduce rapidly first, then reduce slowly, and then rise slowly. With the optimal parameters at the jet angle of 60°, compared with the control sample, the average friction coefficient was reduced from 0.2235 to 0.1609, and the wear volume and specific wear rate were reduced from 9.04 × 10−3 mm3 to 3.82 × 10−3 mm3 and from 15.13 × 10−3 mm2/N to 6.36 × 10−3 mm2/N, respectively. When the jet angle was 90°, the reduced wear resistance was mainly attributed to the excessive roughness that caused the oil coating on the surface to be severely damaged.

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CHEN, XIAOHUI, TAO SHI, YUREN TIAN, JOESEPH JANKOVSKY, R. GLYNN HOLT, and ROBERT E. APFEL. "Numerical simulation of superoscillations of a Triton-bearing drop in microgravity." Journal of Fluid Mechanics 367 (July 25, 1998): 205–20. http://dx.doi.org/10.1017/s002211209800161x.

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Large-amplitude nonlinear oscillations of an axially symmetric water drop of volume 7.33 cm3, initial aspect ratio 3.4, with surfactant Triton X-100 of 1.4×10−4 g ml−1 (1 CMC), in microgravity are compared with predictions of the boundary-integral method. The small shear viscosity of the bulk phase, as well as the surface dilatational viscosity and surface shear viscosity are considered. When a very specific set of material properties is assumed, numerical simulations of the drop oscillations are in good agreement with the experimental results of drop oscillations measured in space during the second United States Microgravity Laboratory, USML-2. The obtained surface viscosities are in rough agreement with literature values.

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Gebretsadik, Daniel W., Jens Hardell, and Braham Prakash. "Seizure behaviour of Pb-free engine bearing materials under dry condition." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 232, no. 2 (April 23, 2017): 106–16. http://dx.doi.org/10.1177/1350650117706641.

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Due to new environmental regulations, Pb-free engine bearing materials are becoming more common and there is a need for studying their tribological performance. Under severe operating conditions, failure due to seizure can occur in engine bearings. In this work, seizure behaviour of different multi-layered engine bearing materials has been studied by using a block-on-ring test setup under dry condition. These materials included Al–Sn-based lining with no overlay, bronze lining with polyamide-imide-based overlay containing MoS2 and graphite, bronze lining with two overlays of Al–Sn-based and polyamide-imide-based material, bronze-based lining with Sn-based overlay and bismuth (Bi)-containing bronze with Sn-based overlay. The tests were performed by gradually increasing the load at a specific time interval and in a stepwise manner and at a constant speed under unidirectional dry sliding conditions. The test materials, counter surfaces and the wear debris were analysed using SEM with a view to understand the seizure mechanisms. Bronze-based lining with a polyamide-imide-based overlay containing MoS2 and graphite does not exhibit seizure up to a load of 475 N. For Al–Sn-based lining without overlay, seizure occurs at a relatively lower load of 125 N. The Al–Sn-based lining with no overlay shows higher friction and the polyamide-imide-based overlay containing MoS2 and graphite shows lower friction during the seizure test. In most cases, there is material transfer onto the test ring counter surface. Material transfer onto the counter surface either due to severe adhesion or wear debris adhered and smeared on it. Al–Sn-based lining and an exposed Al–Sn-based overlay show severe adhesion that causes seizure. On the other hand, exposed Pb containing lining and Bi containing lining seize due to mechanical interlocking caused by the adhered wear debris on both surfaces.

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Song, Inu, and Hirohiko Ise. "Development of a Gene Delivery System of Oligonucleotides for Fibroses by Targeting Cell-Surface Vimentin-Expressing Cells with N-Acetylglucosamine-Bearing Polymer-Conjugated Polyethyleneimine." Polymers 12, no. 7 (July 7, 2020): 1508. http://dx.doi.org/10.3390/polym12071508.

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Targeting myofibroblasts and activated stellate cells in lesion sites of fibrotic tissues is an important approach to treat fibroses. Herein, we focused on targeting the cytoskeletal proteins vimentin, which are reportedly highly expressed on the surface of these cells and have N-acetylglucosamine (GlcNAc)-binding activity. A GlcNAc-bearing polymer synthesized via radical polymerization with a reversible addition-fragmentation chain transfer reagent has been previously found to interact with cell-surface vimentin-expressing cells. We designed a GlcNAc-bearing polymer-conjugated polyethyleneimine (PEI), as the gene carrier to target cell-surface vimentin-expressing cells and specifically deliver nuclear factor-κB decoy oligonucleotides (ODNs) and heat shock protein 47 (HSP47)-small interfering RNA (siRNA) to normal human dermal fibroblasts (NHDFs) that express cell-surface vimentin. The results showed that the expression of tumor necrosis factor-α in lipopolysaccharide-stimulated NHDFs and HSP47 in transforming growth factor-β1-stimulated NHDFs was suppressed by cellular uptake of the GlcNAc-bearing polymer-conjugated PEI/nuclear factor (NF)-κB decoy ODNs and HSP47-siRNA complexes through cell-surface vimentin, respectively. These findings suggest that the effective and specific delivery of ODNs and siRNA for cell-surface vimentin-expressing cells such as myofibroblasts and activated stellate cells can be achieved using GlcNAc-bearing polymer-conjugated PEI. This therapeutic approach could prove advantageous to prevent the promotion of various fibroses.

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SUŁEK, Marian W., Wiesław HRECZUCH, Jacek PRZEPIÓRKA, and Anna ADACH. "SOLUTIONS OF WATER STERICALLY SPECIFIC SURFACTANTS AS MODEL ECOLOGICAL CUTTING FLUIDS." Tribologia 271, no. 1 (February 28, 2018): 87–95. http://dx.doi.org/10.5604/01.3001.0010.6368.

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From the large group of surfactants with branched chains, sulfosuccinate derivatives obtained based on 2-ethylhexyl alcohol were selected. The surfactant of reference was ethoxylated sulfosuccinate with an alkyl chain (C12-C14). Tests regarding foam-forming ability (V0) and foam stability (V10) for selected solutions of the three surfactants were performed. Foam stability of the solutions of sterically specific surfactants (P13, P14) decreased by up to a factor of ten as compared with the equivalent linear alkyl chain (P19). This was achieved with the high surface activity of the solutions of these compounds as represented by surface tension and wettability of the surface of the bearing steel. The consequence of the high surface activity of the compounds were low friction and wear in tribological tests at constant load and excellent anti-seizure properties. On the cooperating friction pairs, adsorption layers were formed, effectively separating the two materials and able to transfer the high loads [L. 3]. Summing up, there is the possibility of using solutions of sterically specific surfactants as model cutting fluids with low foaming ability.

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He, Xia, Lin Zhong, Guorong Wang, Yang Liao, and Qingyou Liu. "Tribological behavior of femtosecond laser textured surfaces of 20CrNiMo/beryllium bronze tribo-pairs." Industrial Lubrication and Tribology 67, no. 6 (September 14, 2015): 630–38. http://dx.doi.org/10.1108/ilt-03-2015-0042.

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Purpose – This paper aims to carry out tribological experiments to explore the applications of femtosecond laser surface texturing technology on rock bit sliding bearing to enhance the lifetime and working performance of rock bit sliding bearing under high temperature and heavy load conditions. Design/methodology/approach – Surface textures on beryllium bronze specimen were fabricated by femtosecond laser ablation (800 nm wavelength, 40 fs pulse duration, 1 kHz pulse repetition frequency), and then the tribological behaviors of pin-on-disc configuration of rock bit bearing were performed with 20CrNiMo/beryllium bronze tribo-pairs under non-Newtonian lubrication of rock bit grease. Findings – The results showed that the surface texture on beryllium bronze specimens with specific geometrical features can be achieved by optimizing femtosecond laser processing via adjusting laser peak power and exposure time; more than 52 per cent of friction reduction was obtained from surface texture with a depth-to-diameter ratio of 0.165 and area ratio of 5 per cent at a shear rate of 1301 s−1 under the heavy load of 20 MPa and high temperature of 120°C, and the lubrication regime of rock bit bearing unit tribo-pairs was improved from boundary to mixed lubrication, which indicated that femtosecond laser ablation technique showed great potential in promoting service life and working performance of rock bit bearing. Originality/value – Femtosecond laser-irradiated surface texture has the potential possibility for application in rock bit sliding bearing to improve the lubrication performance. Because proper micro dimples showed good lubrication and wear resistance performance for unit tribo-pairs of rock bit sliding bearing under high temperature, heavy load and non-Newtonian lubrication conditions, which is very important to improve the efficiency of breaking rock and accelerate the development of deep-water oil and gas resources.

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Araneo, B. A., and R. L. Yowell. "MHC-linked immune response suppression mediated by T cells bearing I-A-encoded determinants." Journal of Immunology 135, no. 1 (July 1, 1985): 73–79. http://dx.doi.org/10.4049/jimmunol.135.1.73.

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Abstract The immune response to chicken egg-white lysozyme (HEL) is actively and specifically regulated by antigen-specific T cell-mediated suppression in mice bearing the H-2b haplotype; the suppression is therefore MHC-linked. In this report, we propose a possible mechanism for MHC-linked suppression of HEL-helper T cells based on expression of I region-encoded cell surface determinants. We determined whether inhibition of anti-HEL antibody responses correlated with expression of serologically detectable I-A-encoded cell surface determinants by antigen-specific helper, suppressor-inducer, or suppressor-effector T cells. It was observed that HEL-suppressor-effector T cells, but not helper or suppressor-inducer T cells, were eliminated after treatment with anti-I-Ab antibody and complement. Furthermore, suppressor-effector T cells co-express Thy-1, Lyt-2, and I-A cell surface antigens. These results raise the possibility that HEL-specific helper T cells become functionally inhibited after recognition of HEL and I-A alloantigen displayed by suppressor-effector T cells. Thus, the interaction between helper and suppressor T cells may be analogous to the mechanism of T cell-B cell interaction.

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Sanjo, Hideki, Masaki Hikida, Yuichi Aiba, Yoshiko Mori, Naoya Hatano, Masato Ogata, and Tomohiro Kurosaki. "Extracellular Signal-Regulated Protein Kinase 2 Is Required for Efficient Generation of B Cells Bearing Antigen-Specific Immunoglobulin G." Molecular and Cellular Biology 27, no. 4 (December 4, 2006): 1236–46. http://dx.doi.org/10.1128/mcb.01530-06.

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ABSTRACT Activation of extracellular signal-regulated protein kinase (ERK) has been implicated in proliferation as well as differentiation in a wide variety of cell types. Using B-cell-specific gene-targeted mice, we report here that in T-cell-dependent immune responses, ERK2 is required to generate efficient immunoglobulin G (IgG) production. In its absence, the proportion of antigen-specific surface IgG1-bearing cells and the subsequent number of IgG1 antibody-secreting cells were decreased, despite apparently unimpaired class switch recombination. Notably, this defect was countered by overexpression of the antiapoptotic factor Bcl-2. Together, our results suggest that ERK2 plays a key role in efficient generation of antigen-specific IgG-bearing B cells by promoting their survival.

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Sivkova, Radoslava, Johanka Táborská, Alain Reparaz, Andres de los Santos Pereira, Ilya Kotelnikov, Vladimir Proks, Jan Kučka, Jan Svoboda, Tomáš Riedel, and Ognen Pop-Georgievski. "Surface Design of Antifouling Vascular Constructs Bearing Biofunctional Peptides for Tissue Regeneration Applications." International Journal of Molecular Sciences 21, no. 18 (September 16, 2020): 6800. http://dx.doi.org/10.3390/ijms21186800.

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Abstract:

Antifouling polymer layers containing extracellular matrix-derived peptide motifs offer promising new options for biomimetic surface engineering. In this contribution, we report the design of antifouling vascular grafts bearing biofunctional peptide motifs for tissue regeneration applications based on hierarchical polymer brushes. Hierarchical diblock poly(methyl ether oligo(ethylene glycol) methacrylate-block-glycidyl methacrylate) brushes bearing azide groups (poly(MeOEGMA-block-GMA-N3)) were grown by surface-initiated atom transfer radical polymerization (SI-ATRP) and functionalized with biomimetic RGD peptide sequences. Varying the conditions of copper-catalyzed alkyne-azide “click” reaction allowed for the immobilization of RGD peptides in a wide surface concentration range. The synthesized hierarchical polymer brushes bearing peptide motifs were characterized in detail using various surface sensitive physicochemical methods. The hierarchical brushes presenting the RGD sequences provided excellent cell adhesion properties and at the same time remained resistant to fouling from blood plasma. The synthesis of anti-fouling hierarchical brushes bearing 1.2 × 103 nmol/cm2 RGD biomimetic sequences has been adapted for the surface modification of commercially available grafts of woven polyethylene terephthalate (PET) fibers. The fiber mesh was endowed with polymerization initiator groups via aminolysis and acylation reactions optimized for the material. The obtained bioactive antifouling vascular grafts promoted the specific adhesion and growth of endothelial cells, thus providing a potential avenue for endothelialization of artificial conduits.

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Journal articles on the topic 'Specific surface bearing'

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