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Experimental study on the feasibility of alternative materials for tilting pad thrust bearings operating in transition to mixed friction

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Friction 2024年第4期12卷 812-822页

作者： michałWASiLCZUK michałWODTKE Faculty of Mechanical Engineering and Ship Technology Gdańsk University of TechnologyGdańsk 80-233Poland

in hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently *** sliding layers are sometimes applied as a valuable *** diamond-like carbon(DLC)coatings,which are also considered for certain applications may show some advantages,as *** material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction conditions,which is crucial for bearings with frequent starts and *** research aimed at studying the performance of fluid film bearings in the specific operating regime,including the transition to mixed friction,is described in the *** tests were carried out on four tilting pad bearings of different material compositions:Steel/bronze,DLC/steel,steel/polyether ether ketone(PEEK),and steel/*** tests comprised stopping under load and reproduction of the Stribeck curve by decreasing rotational speed to very low values,and observing the changes of friction force during the transition to mixed friction *** of the transition conditions and other results showed clear differences between the tested bearings,illustrating the feasibility of less popular material compositions for bearings operating in specific *** specifically,the DLC/steel bearing was demonstrating superior performance,*** friction,transition to mixed friction occurring at higher load,and more stable performance at start-stop regime over the other tested bearings.

关键词： tilting pad thrust bearing experimental research start-stop regime polyether ether ketone(PEEK) diamond-like carbon(DLC)coating metallic bearing alloys

Coarse to Fine: The Role of Severe Plastic Deformation in Advancing Titanium-Based Medical implants - A Comprehensive Review

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 295-306页

作者： Dragana R Mihajlović Bojan i Međo ivana Lj Cvijović-Alagić Veljko R Djokić Faculty of Technology and Metallurgy University of BelgradeKarnegijeva 411120 BelgradeSerbia Vinča institute of Nuclear Sci-ences-National institute of the Republic of Serbia University of Belgrade11001BeogradSerbia innovation Centre of the Faculty of Technology and Metallurgy Karnegijeva 411120 BelgradeSerbia

This paper describes severe plastic deformation(SPD)procedures,which are utilized to form an ultrafine-grained structure in metallic *** the SPD process,a solid material sample is subjected to very high loads without a significant change in sample *** the present work,the high-pressure torsion(HPT)process,as one of the SPD techniques,which achieves a high degree of deformation and ensures refinement of the microstructure,will be discussed in more *** that grain size control is accepted as a method to obtain materials with desired characteristics,an overview of the properties of ultrafine-grained titanium-based biomaterials to be used in medicine is ***,particular attention is dedicated to the influences of HPT process parameters,primarily hydrostatic pressure,and number of revolutions during torsion,on the grain size and physical and mechanical characteristics(modulus of elasticity,microhardness,and tensile properties),corrosion resistance,and biocompatibility of the titanium-based biomaterials.A review of the literature indicates that titanium-based materials obtained by the SPD process show improved mechanical and physical properties without losing biocompatibility and corrosion resistance,which suggests that these methods of obtaining implants are something that should be further developed in the future.

关键词： high-pressure torsion process ultrafine-grained titanium-based materials electrochemical anodization physical properties mechanical properties

Effect of presence of lifting pocket on the THD performance of a large tilting-pad thrust bearing

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Friction 2015年第4期3卷 266-274页

作者： Michel FiLLON michałWODTKE michałWASiLCZUK institut Pprime CNRS-Universitéde Poitiers-ISAE-ENSMADépartement Génie Mécanique et Systèmes ComplexesBP 30169SP2MI86962 Futuroscope Chasseneuil CedexFrance Faculty of Mechanical Engineering Gdansk University of TechnologyGdanskPoland

Hydrostatic assistance is a commonly used method to improve limited load carrying ability of tilting-pad thrust bearings during transient states of operation of vertical shaft *** of special hydraulic equipment(as pumps,valves,etc.),it also requires manufacturing of special recesses/pockets at pad sliding surfaces,into which oil is injected under high *** allows to lift the rotor before start-up of the machine and form a hydrostatic film between pads and *** is a quite wide variety of geometry of recesses(shape,depth,and size)met in practical large bearing *** presence of a hydrostatic pocket(usually located in the sliding surface above the pivot area,where thin film,high oil pressure and temperature are observed)affects bearing performance under hydrodynamic *** theoretical researches,there is an almost common practice not to include hydrostatic recess in thermohydrodynamic(THD)or thermoelastohydrodynamic(TEHD)*** is probably due to the problems with obtaining solution for oil film geometry with pocket,the order of magnitude of the pocket depths being larger than gap *** this paper,an attempt was taken to study the effect of lifting pocket on THD performance of a large tilting-pad thrust bearing of itaipu power *** performance was evaluated including recess shape for several cases of its *** results show that hydrostatic recess changes calculated bearing properties quite significantly,especially in vicinity of the pocket.

关键词： lifting pocket tilting-pad thrust bearing THD regime numerical simulations

Multisensory mechanisms of gait and balance in Parkinson’s disease:an integrative review

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Neural Regeneration Research 2025年第1期20卷 82-92页

作者： Stiven Roytman Rebecca Paalanen Giulia Carli Uros Marusic Prabesh Kanel Teus van Laar Nico i.Bohnen Department of Radiology University of MichiganAnn ArborMIUSA Department of Neurology University of MichiganAnn ArborMIUSA Morris K.Udall Center of Excellence for Parkinson’s Disease Research University of MichiganAnn ArborMIUSA institute for Kinesiology Research Science and Research Centre KoperKoperSlovenia Department of Health Sciences Alma Mater Europaea–ECMMariborSlovenia Parkinson’s Foundation Research Center of Excellence University of MichiganAnn ArborMIUSA Department of Neurology University of GroningenUniversity Medical Center GroningenGroningenThe Netherlands Neurology Service and GRECC VA Ann Arbor Healthcare SystemAnn ArborMIUSA

Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging *** and gait control does not happen automatically,as previously believed,but rather requires continuous involvement of central nervous *** effectively exert control over the body,the brain must integrate multiple streams of sensory information,including visual,vestibular,and somatosensory *** mechanisms which underpin the integration of these multisensory signals are the principal topic of the present *** multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older *** emphasis,however,has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and *** the present work,we review the contributions of somatosensory,visual,and vestibular modalities,along with their multisensory intersections to gait and balance in older adults and patients with Parkinson’s *** also review evidence of vestibular contributions to multisensory temporal binding windows,previously shown to be highly pertinent to fall risk in older ***,we relate multisensory vestibular mechanisms to potential neural substrates,both at the level of neurobiology(concerning positron emission tomography imaging)and at the level of electrophysiology(concerning electroencephalography).We hope that this integrative review,drawing influence across multiple subdisciplines of neuroscience,paves the way for novel research directions and therapeutic neuromodulatory approaches,to improve the lives of older adults and patients with neurodegenerative diseases.

关键词： aging balance encephalography functional magnetic resonance imaging gait multisensory integration Parkinson’s disease positron emission tomography somatosensory vestibular visual

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Momentum considerations inside near-zero index materials

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Light(Science & Applications) 2022年第8期11卷 1782-1789页

作者： michaël Lobet iñigo Liberal Larissa Vertchenko Andrei VLavrinenko Nader Engheta Eric Mazur John A.Paulson School of Engineering and Applied Sciences Harvard University9 Oxford StreetCambridgeMA02138USA Department of Physics and Namur institute of Structured Materials University of NamurRue de Bruxelles 515000NamurBelgium Electrical and Electronic Engineering Department Universidad Pública de NavarraCampus ArrosadíaPamplona31006Spain Department of Photonics Engineering Technical University of DenmarkØrsteds Plads 345ADK-2800 KgsLyngbyDenmark Department of Electrical and Systems Engineering University of PennsylvaniaPhiladelphiaPA19104USA

Near-zero index (NZi) materials, i.e., materials having a phase refractive index close to zero, are known to enhance or inhibit light-matter interactions. Most theoretical derivations of fundamental radiative processes rely on energetic considerations and detailed balance equations, but not on momentum considerations. Because momentum exchange should also be incorporated into theoretical models, we investigate momentum inside the three categories of NZi materials, i.e., inside epsilon-and-mu-near-zero (EMNZ), epsilon-near-zero (ENZ) and mu-near-zero (MNZ) materials. in the context of Abraham–Minkowski debate in dispersive materials, we show that Minkowski-canonical momentum of light is zero inside all categories of NZi materials while Abraham-kinetic momentum of light is zero in ENZ and MNZ materials but nonzero inside EMNZ materials. We theoretically demonstrate that momentum recoil, transfer momentum from the field to the atom and Doppler shift are inhibited in NZi materials. Fundamental radiative processes inhibition is also explained due to those momentum considerations inside three-dimensional NZi materials. Absence of diffraction pattern in slits experiments is seen as a consequence of zero Minkowski momentum. Lastly, consequence on Heisenberg inequality, microscopy applications and on the canonical momentum as generator of translations are discussed. Those findings are appealing for a better understanding of fundamental light-matter interactions at the nanoscale as well as for lasing applications.

关键词： materials. momentum Minkowski

Evaluating the impact of thermostat control strategies on the energy flexibility of residential buildings for space heating

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Building Simulation 2021年第5期14卷 1439-1452页

作者： Kun Zhang michaël Kummert Department of Mechanical Engineering Polytechnique MontrealMontrealCanada

Buildings can be operated in an energy-flexible manner while respecting occupant thermal *** energy flexibility of building operations,both in time and quantity,can be harnessed by the electrical grid for load *** the context of smart grid and intelligent buildings,the concept of energy flexibility in buildings broadens the existing demand management thinking from the top-down one-way control to two-way *** paper,extending studies on thermostat controls of heating and air conditioning systems for demand response,evaluates the impact of different control schemes on the energy flexibility of residential *** control strategies,Model Predictive Control(MPC)and Rule-Based Control(RBC),are investigated for a space heating system using co-simulation *** indicators are introduced and adapted from the literature to assess the control performances of the *** results show that different flexibility indicators favour different control strategies in this case *** demand response events of four hours,the MPC strategy presents two to three times of flexible energy than that of *** also delivers 20%more of maximum power reduction during the events against *** RBC strategy,on the other hand,is twice of MPC for flexible energy *** evaluation work can be beneficial to guide the control system design of new buildings or control retrofits of existing buildings that consider better grid-building interactions for the future.

关键词： energy flexibility MPC grid-building interaction demand response

Apolipoprotein A-i binding protein-mediated neuroprotection in glaucomatous neuroinflammation and neurodegeneration

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Neural Regeneration Research 2025年第5期20卷 1414-1415页

作者： Sinwoo Hwang Seunghwan Choi Soo-Ho Choi Keun-Young Kim Yury i.Miller Won-Kyu Ju Hamilton Glaucoma Center and Shiley Eye institute The Viterbi Family Department of OphthalmologyUniversity of California San DiegoLa JollaCAUSA Department of Medicine University of California San DiegoLa JollaCAUSA National Center for Microscopy and imaging Research Department of NeurosciencesUniversity of California San DiegoLa JollaCAUSA

Glaucoma is a multifactorial eye disorder that can cause vision loss and irreversible blindness,affecting individ uals aged 40 to 80 yea rs *** to the aging population,it is expected that the number of people affected by glaucoma will surpass 111 million by 2040 as the disease becomes more *** primarily contributes to optic nerve axon loss and the progressive degeneration of retinal ganglion cells (RGCs),subsequently leading to vision impairment.

关键词： irreversible pass primarily

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Occupational risk assessment based on employees’ knowledge and awareness of hazards in mining

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international Journal of Coal Science & Technology 2022年第5期9卷 113-123页

作者： michał Patyk Dagmara Nowak‑Senderowska Department of Mining Engineering and Work Safety Faculty of Civil Engineering and Resource ManagementAGH University of Science and TechnologyAl.Mickiewicza 3030-059 CracowPoland

Analyses and assessments of hazards occurring in work processes are carried out by teams,in which there is usually one representative of the personnel,as the embodiment of the active participation of employees in the assessment of occupational *** is why the article presents research on all employees’knowledge and awareness about risks in their work *** research was carried out in the form of an employee survey in one of the open-pit mines,at workstations dealing with the loading and transporting of excavated *** survey included a list of 40 hazards divided into four groups:(1)hazards related to machines and equipment used,(2)hazards related to exposure,(3)hazards with an impact extending beyond the workstation and(4)hazards of an ergonomic nuisance nature,where employees were required to indicate which hazards apply to their workplaces and determine their level of signifcance,probability of occurrence and the scale of possible *** this way,a hierarchical identifcation of threats occurring at the analyzed workplaces was made,and the obtained results were used to determine the amount of occupational risk both for specifc workstations and for the whole technological *** measures of the magnitude of occupational risk obtained using the proposed method have showed that,according to the respondents,greatest risks at the workstation are associated with moving machines and vehicles and with mobile *** important risks,which were often mentioned by employees,were those directly related to their health,i.e.,related to ergonomic nuisance and *** resulting from geological and mining conditions,considered typical for mining,were important for the surveyed miners but they were not the most important owing to proper prevention,good organization of work and high safety culture The active involvement of the crew in the process of assessing occupational hazards allowed to identify the signifcance of each hazard,in t

关键词： Hazards in mining Occupational risk assessment Employee survey Open-pit mining

Nano-Enhanced Dairy Scum Biodiesel Blends:Unleashing the Power of Aluminium Oxide for Sustainable and Efficient Engine Performance

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Journal of Thermal Science 2025年第1期34卷 283-302页

作者： Veeranna MODi Prasad B.RAMPURE Sunil Kumar SHETTY Madeva NAGARAL Channa Keshava NAiK N Johar MGM Muhammad irsyad ABDULLAH Abdullah i.AL-MANSOUR Shamshad ALAM KLE College of Engineering and Technology ChikodiVisvesvaraya Technological University Nitte (Deemed to be University) NMAM Institute of Technology (NMAMIT)Department of Mechanical Engineering Aircraft Research and Design Centre HAL Department of Mechanical Engineering BGS College of Engineering and TechnologyBengaluruAffiliated to Visvesvaraya Technological University Management and Science University Department of Civil Engineering College of EngineeringKing Saud University

This study investigates the effect of aluminium oxide nanoparticlesaddition to biodiesel blends made from dairy milk scum on performance and combustion characteristics of the diesel *** dispersion of Al2O3nanoparticles in B20 blends at different concentrations was done with the help of *** number of blends were prepared for the *** Machine learning algorithms(Random Forest（RF）and CatBoost) was used for the *** results show that in comparison to biodiesel blends without nanoparticles,the kinematic viscosity and density is higher for fuel blends with *** these Fuel blends have higher calorific *** blends exhibited reduced Brake Specific Fuel Consumption（BSFC） of2.85% than the blends without nano particles(Dairy Scum Methyl Ester Biodiesel 20%+Neat Diesel 80%（in volume）,DSMEB20),57.14% less CO,40.8% less hydrocarbon,and increased NOxemissions compared to conventional diesel,contributing to the development of environmentally friendly and renewable biofuel blends with *** B20NP30 is the optimal blend for performance and emission *** study concludes with findings on enhanced Brake Thermal Efficiency（BTE） of 26.29% in 3×10-5（in volume） Al2O3nanoparticle-blended DSME B20 and other DSME B20 fuel blends,emphasizing the importance of optimal nanoparticle *** correlation matrix shows how engine load,efficiency measures（BTE,BSFC）,and emissions（CO,CO2,NOx,Smoke） are connected in complex *** results help us understand the complicated dynamics of engine performance and emission characteristics ***'s diagram for BTE and BSFC shows that CatBoost-based BTE models perform superior to RF-based models during the training as well as testing *** results were obtained for CO and CO2emission results.

关键词： Al2O3 concentration Ci engine Dairy Scum Methyl Ester Biodiesel