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Bougouin A, Metzger B, Forterre Y, Boustingorry P, Lhuissier H. A frictional soliton controls the resistance law of shear-thickening suspensions in pipes. Proc Natl Acad Sci U S A 2024; 121:e2321581121. [PMID: 38625944 PMCID: PMC11046699 DOI: 10.1073/pnas.2321581121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 03/14/2024] [Indexed: 04/18/2024] Open
Abstract
Pipe flows are commonly found in nature and industry as an effective mean of transporting fluids. They are primarily characterized by their resistance law, which relates the mean flow rate to the driving pressure gradient. Since Poiseuille and Hagen, various flow regimes and fluid rheologies have been investigated, but the behavior of shear-thickening suspensions, which jam above a critical shear stress, remains poorly understood despite important applications (e.g., concrete or food processing). In this study, we build on recent advances in the physics of shear-thickening suspensions to address their flow through pipes and establish their resistance law. We find that for discontinuously shear-thickening suspensions (large particule volume fractions), the flow rate saturates at high driving stress. Local pressure and velocity measurements reveal that this saturation stems from the emergence of a frictional soliton: a unique, localized, superdissipative, and backpropagating flow structure coexisting with the laminar frictionless flow phase observed at low driving stress. We characterize the remarkably steep effective rheology of the frictional soliton and show that it sets the resistance law at the whole pipe scale. These findings offer an unusual perspective on low-Reynolds suspension flows through pipes, intriguingly reminiscent of the transition to turbulence for simple fluids. They also provide a predictive law for the transport of such suspensions in pipe systems, with implications for a wide range of applications.
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Affiliation(s)
- Alexis Bougouin
- Aix Marseille Univ, CNRS, Institut Universitaire des Systèmes Thermiques et Industriels, Marseille13453, France
| | - Bloen Metzger
- Aix Marseille Univ, CNRS, Institut Universitaire des Systèmes Thermiques et Industriels, Marseille13453, France
| | - Yoël Forterre
- Aix Marseille Univ, CNRS, Institut Universitaire des Systèmes Thermiques et Industriels, Marseille13453, France
| | | | - Henri Lhuissier
- Aix Marseille Univ, CNRS, Institut Universitaire des Systèmes Thermiques et Industriels, Marseille13453, France
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2
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Atapour M, Standish TE, Henderson JD, Wei Z, Dehnavi V, Hedberg YS. Influence of Proteins and Building Direction on the Corrosion and Tribocorrosion of CoCrMo Fabricated by Laser Powder Bed Fusion. ACS Biomater Sci Eng 2024. [PMID: 38630940 DOI: 10.1021/acsbiomaterials.3c01165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
Cobalt-chromium-molybdenum (CoCrMo) alloys are common wear-exposed biomedical alloys and are manufactured in multiple ways, increasingly using additive manufacturing processes such as laser powder bed fusion (LPBF). Here, we investigate the effect of proteins and the manufacturing process (wrought vs LPBF) and building orientation (LPBF-XY and XZ) on the corrosion, metal release, tribocorrosion, and surface oxide composition by means of electrochemical, mechanical, microscopic, diffractive, and spectroscopic methods. The study was conducted at pH 7.3 in 5 g/L NaCl and 5 mM 2-(N-morpholino) ethanesulfonic acid (MES) buffer, which was found to be necessary to avoid metal phosphate and metal-protein aggregate precipitation. The effect of 10 g/L bovine serum albumin (BSA) and 2.5 g/L fibrinogen (Fbn) was studied. BSA and Fbn strongly enhanced the release of Co, Cr, and Mo and slightly enhanced the corrosion (still in the passive domain) for all CoCrMo alloys and most for LPBF-XZ, followed by LPBF-XY and the wrought CoCrMo. BSA and Fbn, most pronounced when combined, significantly decreased the coefficient of friction due to lubrication, the wear track width and severity of the wear mechanism, and the tribocorrosion for all alloys, with no clear effect of the manufacturing type. The wear track area was significantly more oxidized than the area outside of the wear track. In the reference solution without proteins, a strong Mo oxidation in the wear track surface oxide was indicative of a pH decrease and cell separation of the anodic and cathodic areas. This effect was absent in the presence of the proteins.
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Affiliation(s)
- Masoud Atapour
- Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7, Canada
| | - Thalia E Standish
- Surface Science Western, The University of Western Ontario, London, Ontario N6G 0J3, Canada
| | - Jeffrey D Henderson
- Surface Science Western, The University of Western Ontario, London, Ontario N6G 0J3, Canada
| | - Zheng Wei
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7, Canada
| | - Vahid Dehnavi
- Surface Science Western, The University of Western Ontario, London, Ontario N6G 0J3, Canada
- Department of Chemical & Biochemical Engineering, The University of Western Ontario, London, Ontario N6A 5B9, Canada
| | - Yolanda S Hedberg
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7, Canada
- Surface Science Western, The University of Western Ontario, London, Ontario N6G 0J3, Canada
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3
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Peeters S, Kuwahara T, Härtwig F, Makowski S, Weihnacht V, Lasagni AF, Dienwiebel M, Moseler M, Moras G. Surface Depassivation via B-O Dative Bonds Affects the Friction Performance of B-Doped Carbon Coatings. ACS Appl Mater Interfaces 2024; 16:18112-18123. [PMID: 38547870 PMCID: PMC11011640 DOI: 10.1021/acsami.3c18803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/27/2024] [Accepted: 03/04/2024] [Indexed: 04/12/2024]
Abstract
Boron doping of diamond-like carbon coatings has multiple effects on their tribological properties. While boron typically reduces wear in cutting applications, some B-doped coatings show poor tribological performance compared with undoped films. This is the case of the tribological tests presented in this work in which an alumina ball is placed in frictional contact with different undoped and B-doped amorphous carbon coatings in humid air. With B-doped coatings, a higher friction coefficient at a steady state with respect to their undoped counterparts was observed. Estimates of the average contact shear stress based on experimental friction coefficients, surface topographies, and Persson's contact theory suggest that the increased friction is compatible with the formation of a sparse network of interfacial ether bonds leading to a mild cold-welding friction regime, as documented in the literature. Tight binding and density functional theory simulations were performed to investigate the chemical effect of B-doping on the interfacial properties of the carbon coatings. The results reveal that OH groups that normally passivate carbon surfaces in humid environments can be activated by boron and form B-O dative bonds across the tribological interfaces, leading to a mild cold-welding friction regime. Simulations performed on different tribological pairs suggest that this mechanism could be valid for B-doped carbon surfaces in contact with a variety of materials. In general, this study highlights the impact that subtle modifications in surface and interface chemistry caused by the presence of impurities can have on macroscopic properties, such as friction and wear.
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Affiliation(s)
- Stefan Peeters
- Fraunhofer
IWM, MiktroTribologie Centrum μTC, Wöhlerstraße 11, 79108 Freiburg, Germany
| | - Takuya Kuwahara
- Fraunhofer
IWM, MiktroTribologie Centrum μTC, Wöhlerstraße 11, 79108 Freiburg, Germany
- Osaka
Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, 558-8585 Osaka, Japan
| | - Fabian Härtwig
- Fraunhofer
IWS, Winterbergstraße 28, 01277 Dresden, Germany
- Technische
Universität Dresden, Institut für
Fertigungstechnik, George-Bähr-Straße
3c, 01069 Dresden, Germany
| | | | | | - Andrés Fabián Lasagni
- Fraunhofer
IWS, Winterbergstraße 28, 01277 Dresden, Germany
- Technische
Universität Dresden, Institut für
Fertigungstechnik, George-Bähr-Straße
3c, 01069 Dresden, Germany
| | - Martin Dienwiebel
- Fraunhofer
IWM, MiktroTribologie Centrum μTC, Wöhlerstraße 11, 79108 Freiburg, Germany
- Karlsruhe
Institute of Technology (KIT), IAM – Institute for Applied
Materials, Straße am Forum 7, 76131 Karlsruhe, Germany
| | - Michael Moseler
- Fraunhofer
IWM, MiktroTribologie Centrum μTC, Wöhlerstraße 11, 79108 Freiburg, Germany
- University
of Freiburg, Institute of Physics, Herrmann-Herder-Straße 3, 79104 Freiburg, Germany
| | - Gianpietro Moras
- Fraunhofer
IWM, MiktroTribologie Centrum μTC, Wöhlerstraße 11, 79108 Freiburg, Germany
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Akakuru OU, Martin-Alarcon L, Bryant S, Trifkovic M. Unraveling Water-Based Lubrication with Carbon Dots of Asphaltene Origin. ACS Appl Mater Interfaces 2024; 16:16699-16711. [PMID: 38514399 DOI: 10.1021/acsami.4c00579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Despite the lower toxicity of water-based lubricants over nonrenewable petroleum-based analogues, they face challenges in achieving widespread adoption due to low stability and inadequate friction-reduction performance. To address this, a cost-effective nanoadditive is synthesized by expansive oxidation of asphaltenes to create biocompatible asphaltene-derived carbon dots [(ACDs); 5 nm]. These ACDs exhibit excellent water redispersibility, promoting long-term friction reduction and marking the first use of an asphaltene-based system for friction reduction in water or oil. Even at low loadings (0.2-4.0 wt %), ACDs significantly reduce friction on steel surfaces (>54%) with tribofilm stability surpassing pristine carbon dots, typical carbon-based graphene quantum dots, and inorganic nanomaterials (commercial 5 and 20 nm silica). The ACDs' attributes include high negative zeta potential, considerable water uptake, varied functional groups, biocompatibility, and a nanodisc shape conducive to stable tribofilm formation through effective particle stacking. The scalable synthesis, high yield, and impressive water redispersibility of ACDs position them favorably for commercial water-based lubrication.
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Affiliation(s)
- Ozioma Udochukwu Akakuru
- Department of Chemical and Petroleum Engineering, Schulich School of Engineering, University of Calgary, Alberta T2N 1N4, Canada
| | - Leonardo Martin-Alarcon
- Department of Chemical and Petroleum Engineering, Schulich School of Engineering, University of Calgary, Alberta T2N 1N4, Canada
| | - Steven Bryant
- Department of Chemical and Petroleum Engineering, Schulich School of Engineering, University of Calgary, Alberta T2N 1N4, Canada
| | - Milana Trifkovic
- Department of Chemical and Petroleum Engineering, Schulich School of Engineering, University of Calgary, Alberta T2N 1N4, Canada
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Kumar R, Rezapourian M, Rahmani R, Maurya HS, Kamboj N, Hussainova I. Bioinspired and Multifunctional Tribological Materials for Sliding, Erosive, Machining, and Energy-Absorbing Conditions: A Review. Biomimetics (Basel) 2024; 9:209. [PMID: 38667221 PMCID: PMC11048303 DOI: 10.3390/biomimetics9040209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
Friction, wear, and the consequent energy dissipation pose significant challenges in systems with moving components, spanning various domains, including nanoelectromechanical systems (NEMS/MEMS) and bio-MEMS (microrobots), hip prostheses (biomaterials), offshore wind and hydro turbines, space vehicles, solar mirrors for photovoltaics, triboelectric generators, etc. Nature-inspired bionic surfaces offer valuable examples of effective texturing strategies, encompassing various geometric and topological approaches tailored to mitigate frictional effects and related functionalities in various scenarios. By employing biomimetic surface modifications, for example, roughness tailoring, multifunctionality of the system can be generated to efficiently reduce friction and wear, enhance load-bearing capacity, improve self-adaptiveness in different environments, improve chemical interactions, facilitate biological interactions, etc. However, the full potential of bioinspired texturing remains untapped due to the limited mechanistic understanding of functional aspects in tribological/biotribological settings. The current review extends to surface engineering and provides a comprehensive and critical assessment of bioinspired texturing that exhibits sustainable synergy between tribology and biology. The successful evolving examples from nature for surface/tribological solutions that can efficiently solve complex tribological problems in both dry and lubricated contact situations are comprehensively discussed. The review encompasses four major wear conditions: sliding, solid-particle erosion, machining or cutting, and impact (energy absorbing). Furthermore, it explores how topographies and their design parameters can provide tailored responses (multifunctionality) under specified tribological conditions. Additionally, an interdisciplinary perspective on the future potential of bioinspired materials and structures with enhanced wear resistance is presented.
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Affiliation(s)
- Rahul Kumar
- Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Ehitajate Tee 5, 19086 Tallinn, Estonia; (M.R.); (H.S.M.); (N.K.); (I.H.)
| | - Mansoureh Rezapourian
- Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Ehitajate Tee 5, 19086 Tallinn, Estonia; (M.R.); (H.S.M.); (N.K.); (I.H.)
| | - Ramin Rahmani
- CiTin–Centro de Interface Tecnológico Industrial, 4970-786 Arcos de Valdevez, Portugal;
- proMetheus–Instituto Politécnico de Viana do Castelo (IPVC), 4900-347 Viana do Castelo, Portugal
| | - Himanshu S. Maurya
- Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Ehitajate Tee 5, 19086 Tallinn, Estonia; (M.R.); (H.S.M.); (N.K.); (I.H.)
- Department of Engineering Sciences and Mathematics, Luleå University of Technology, 97187 Luleå, Sweden
| | - Nikhil Kamboj
- Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Ehitajate Tee 5, 19086 Tallinn, Estonia; (M.R.); (H.S.M.); (N.K.); (I.H.)
- Department of Mechanical and Materials Engineering, University of Turku, 20500 Turku, Finland
- TCBC–Turku Clinical Biomaterials Centre, Department of Biomaterials Science, Faculty of Medicine, Institute of Dentistry, University of Turku, 20014 Turku, Finland
| | - Irina Hussainova
- Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Ehitajate Tee 5, 19086 Tallinn, Estonia; (M.R.); (H.S.M.); (N.K.); (I.H.)
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Hernandez AM, Sandoval JA, Yuen MC, Wood RJ. Stickiness in shear: stiffness, shape, and sealing in bioinspired suction cups affect shear performance on diverse surfaces. Bioinspir Biomim 2024; 19:036008. [PMID: 38528733 DOI: 10.1088/1748-3190/ad2c21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 02/22/2024] [Indexed: 03/27/2024]
Abstract
Aquatic organisms utilizing attachment often contend with unpredictable environments that can dislodge them from substrates. To counter these forces, many organisms (e.g. fish, cephalopods) have evolved suction-based organs for adhesion. Morphology is diverse, with some disc shapes deviating from a circle to more ovate designs. Inspired by the diversity of multiple aquatic species, we investigated how bioinspired cups with different disc shapes performed in shear loading conditions. These experiments highlighted pertinent physical characteristics found in biological discs (regions of stiffness, flattened margins, a sealing rim), as well as ecologically relevant shearing conditions. Disc shapes of fabricated cups included a standard circle, ellipses, and other bioinspired designs. To consider the effects of sealing, these stiff silicone cups were produced with and without a soft rim. Cups were tested using a force-sensing robotic arm, which directionally sheared them across surfaces of varying roughness and compliance in wet conditions while measuring force. In multiple surface and shearing conditions, elliptical and teardrop shapes outperformed the circle, which suggests that disc shape and distribution of stiffness may play an important role in resisting shear. Additionally, incorporating a soft rim increased cup performance on rougher substrates, highlighting interactions between the cup materials and surfaces asperities. To better understand how these cup designs may resist shear, we also utilized a visualization technique (frustrated total internal reflection; FTIR) to quantify how contact area evolves as the cup is sheared.
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Affiliation(s)
- Alyssa M Hernandez
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, United States of America
- Project CETI, New York, NY 10003 United States of America
| | - Jessica A Sandoval
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, United States of America
- Project CETI, New York, NY 10003 United States of America
| | - Michelle C Yuen
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, United States of America
- Project CETI, New York, NY 10003 United States of America
| | - Robert J Wood
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, United States of America
- Project CETI, New York, NY 10003 United States of America
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Estrada Munoz OI, Sabour AF, Carroll JT, Flores CE, Fraser DR, Chestovich P, Saquib SF. From Admission to Discharge - A Total Friction Burn Review from a Single Institution. J Burn Care Res 2024:irad148. [PMID: 38520289 DOI: 10.1093/jbcr/irad148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Indexed: 03/25/2024]
Abstract
While most friction burns are adequately managed in an outpatient setting, many may require hospital admission, operative excision, and extended care. To this day, there is a wide variance in friction burn management. Our goal is to review the etiology, management, and outcomes of such burns warranting hospitalization. We conducted a retrospective review of all friction burns admitted to a single, American Burn Association verified burn center from January 1, 2016 to December 31, 2020. 28 (34%) patients required surgery for their friction burns and 15 (18%) ultimately required a split-thickness skin graft. The mean number of operations was 2.4 (95% CI 1.6-3.1). Overall, the operative group was younger (29.9 vs 38.3 years, p=0.026), more likely to have a concomitant traumatic brain injury (25% vs 7%, p=0.027) and had a longer hospital length of stay (17.5 vs 3.9 days, p<0.001). Both groups had a similar overall TBSA (8.5% vs 10.0%, p=0.35), but the operative group had larger surface area comprised of 3rd degree burns (3.05% vs 0.2%, p<0.001). Overall, friction burns resulting in hospital admission are associated with high-energy traumatic mechanisms and concomitant injuries. Patients who need operative intervention of their burns typically require multiple procedures often culminating in a split-thickness skin graft. While non-operative management of friction burns with topical agents has been found to be successful, patients with higher injury severity scores should be monitored very closely as they may require surgical excision.
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Affiliation(s)
| | - Andrew F Sabour
- Division of Surgery, Kirk Kerkorian School of Medicine at UNLV, Las Vegas, NV
| | - Joseph T Carroll
- Division of Surgery, Kirk Kerkorian School of Medicine at UNLV, Las Vegas, NV
| | - Carmen E Flores
- Division of Surgery, Kirk Kerkorian School of Medicine at UNLV, Las Vegas, NV
| | - Douglas R Fraser
- Division of Surgery, Kirk Kerkorian School of Medicine at UNLV, Las Vegas, NV
| | - Paul Chestovich
- Division of Surgery, Kirk Kerkorian School of Medicine at UNLV, Las Vegas, NV
| | - Syed F Saquib
- Division of Surgery, Kirk Kerkorian School of Medicine at UNLV, Las Vegas, NV
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Hayler HJ, Groves TS, Guerrini A, Southam A, Zheng W, Perkin S. The surface force balance: direct measurement of interactions in fluids and soft matter. Rep Prog Phys 2024; 87:046601. [PMID: 38382100 DOI: 10.1088/1361-6633/ad2b9b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/21/2024] [Indexed: 02/23/2024]
Abstract
Over the last half-century, direct measurements of surface forces have been instrumental in the exploration of a multitude of phenomena in liquid, soft, and biological matter. Measurements of van der Waals interactions, electrostatic interactions, hydrophobic interactions, structural forces, depletion forces, and many other effects have checked and challenged theoretical predictions and motivated new models and understanding. The gold-standard instrument for these measurements is thesurface force balance(SFB), orsurface forces apparatus, where interferometry is used to detect the interaction force and distance between two atomically smooth planes, with 0.1 nm resolution, over separations from about 1 µm down to contact. The measured interaction forcevs.distance gives access to the free energy of interaction across the fluid film; a fundamental quantity whose general form and subtle features reveal the underlying molecular and surface interactions and their variation. Motivated by new challenges in emerging fields of research, such as energy storage, biomaterials, non-equilibrium and driven systems, innovations to the apparatus are now clearing the way for new discoveries. It is now possible to measure interaction forces (and free energies) with control of electric field, surface potential, surface chemistry; to measure time-dependent effects; and to determine structurein situ. Here, we provide an overview the operating principles and capabilities of the SFB with particular focus on the recent developments and future possibilities of this remarkable technique.
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Affiliation(s)
- Hannah J Hayler
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Timothy S Groves
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Aurora Guerrini
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Astrid Southam
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Weichao Zheng
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Susan Perkin
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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Gkougkousi K, Karantzalis AE, Nikolakopoulos PG, Dassios KG. Synergistic Effect of Carbon Micro/Nano-Fillers and Surface Patterning on the Superlubric Performance of 3D-Printed Structures. Materials (Basel) 2024; 17:1215. [PMID: 38473685 DOI: 10.3390/ma17051215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/21/2024] [Accepted: 03/01/2024] [Indexed: 03/14/2024]
Abstract
Superlubricity, the tribological regime where the coefficient of friction between two sliding surfaces almost vanishes, is currently being investigated as a viable route towards the energy efficiency envisioned by major long-term strategies for a sustainable future. This current study provides new insights towards the development of self-lubricating systems by material and topological design, systems which tend to exhibit near-superlubric tribological performance, by reporting the synergistic effect of selective surface patterning and presence of carbon micro/nano-fillers on the frictional coefficients of additively manufactured structures. Geometric and biomimetic surface patterns were prepared by fused deposition modelling (FDM), using printing filaments of a polymeric matrix infused with graphene nanoplatelets (GNPs) and carbon fibers (Cf). The calorimetric, spectroscopic, mechanical and optical microscopy characterization of the starting materials and as-printed structures provided fundamental insights for their tribological characterization under a ball-on-disk configuration. In geometrically patterned PLA-based structures, a graphene presence reduced the friction coefficient by ca. 8%, whereas PETG exhibited the lowest coefficients, in the vicinity of 0.1, indicating a high supelubric potential. Biomimetic patterns exhibited an inferior frictional response due to their topologically and tribologically anisotropy of the surfaces. Overall, a graphene presence in the starting materials demonstrated great potential for friction reduction, while PETG showed a tribological performance not only superior to PLA, but also compatible with superlubric performance. Methodological and technical challenges are discussed in the text.
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Affiliation(s)
- Katerina Gkougkousi
- Department of Chemical Engineering, University of Patras, Caratheodory 1, 26504 Patras, Greece
| | | | - Pantelis G Nikolakopoulos
- Department of Mechanical Engineering and Aeronautics, University of Patras, 26504 Rio Patras, Greece
| | - Konstantinos G Dassios
- Department of Chemical Engineering, University of Patras, Caratheodory 1, 26504 Patras, Greece
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10
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Gakkhar A, Mehendale AM, Mehendale S. An Interesting Case of Macular Amyloidosis With No Significant Etiology. Cureus 2024; 16:e56248. [PMID: 38623100 PMCID: PMC11016991 DOI: 10.7759/cureus.56248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 03/15/2024] [Indexed: 04/17/2024] Open
Abstract
Macular amyloidosis is primary localized cutaneous amyloidosis (PLCA). It is described by the extracellular accumulation of heterogenic amyloid proteins in the skin that does not affect the systemic immune system, causing hyperpigmented patches. It is a prevalent skin disorder of young female adults, especially in India, since it affects the population with darker skin. History of frictional rub on the skin is typically present, such as using loofah or bathing scrubs or stones. The case presented below is of a 23-year-old female who presented with a hyperpigmented patch on the upper back of both sides and extensor surface of arms and did not have any history of usage of loofah on those areas, compelling us to research more on the other causative factors (genetic predisposition, infectious agents, and UV radiation are probable causative factors) for macular amyloidosis. This condition is not entirely cured; it is managed symptomatically only to improve cosmetic outcomes.
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Affiliation(s)
- Avni Gakkhar
- Preventive Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Ashok M Mehendale
- Preventive Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Shivansh Mehendale
- Preventive Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
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11
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Tang C, Lin P, Zhao Y, Wang P, Wang P. A Retrospective Study: Clinical Characteristics and Lifestyle Analysis of Chinese Senile Gluteal Dermatosis Patients. Clin Interv Aging 2024; 19:333-338. [PMID: 38434574 PMCID: PMC10906672 DOI: 10.2147/cia.s448026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 02/14/2024] [Indexed: 03/05/2024] Open
Abstract
Purpose To summarize the clinical, histopathological and therapeutic features of senile gluteal dermatosis. Patients and Methods Retrospective analysis of 230 cases who visited the outpatient clinic of Hangzhou No. 3 People's Hospital for skin lesions on the buttocks and hips from 2018.8-2023.8 were included in the study, basic clinical information was collected, and they were subjected to physical examination of the buttocks and hips, and 36 cases were senile gluteal dermatosis, of which 7 underwent histopathological biopsy. Results A total of 230 patients were included, of which 36 were diagnosed with geriatric buttock dermatosis, with a mean age of (84.2±12.6) years, mean body mass index of (21.7±3.8) kg/m2, and a male to female ratio of 2:1. There was a significant correlation between the occurrence of the disease and age, gender, body mass index, sedentary time, type of chair used, and hypertension (P<0.05). The severity of the lesions may be associated with longer sitting time and prolonged use of bamboo chairs (P<0.05). Histopathologic changes were not specific. The skin lesions could subside after general treatment such as improvement of lifestyle, use of pressure-reducing air mattresses, salicylic acid cream, and moisturizing creams. Conclusion Senile gluteal dermatosis is a common senile physical dermatosis, mainly manifested as brownish scaly plaques, erythema and crusted ulcers, which can often be cured under reasonable treatment.
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Affiliation(s)
- Chenyu Tang
- Department of Dermatology, Hangzhou Third People’s Hospital, Zhejiang Chinese Medical University, Hangzhou, People’s Republic of China
| | - Ping Lin
- Department of Gerontology, Hangzhou Third People’s Hospital, Hangzhou, People’s Republic of China
| | - Yige Zhao
- Department of Dermatology, Hangzhou Third People’s Hospital, Zhejiang Chinese Medical University, Hangzhou, People’s Republic of China
| | - Panpan Wang
- Department of Dermatology, Hangzhou Third People’s Hospital, Zhejiang Chinese Medical University, Hangzhou, People’s Republic of China
| | - Ping Wang
- Department of Dermatology, Hangzhou Third People’s Hospital, Hangzhou, People’s Republic of China
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12
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Zhuang S, Cao Y, Song W, Zhang P, Choi SB. Effect of Additives on Tribological Performance of Magnetorheological Fluids. Micromachines (Basel) 2024; 15:270. [PMID: 38398998 PMCID: PMC10892829 DOI: 10.3390/mi15020270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/05/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024]
Abstract
In this study, nano-diamond (ND) and MoS2 powder are used as additives in a carbonyl iron-based magnetorheological fluid (MRF) to improve its tribological performance. MRFs are prepared by dispersing 35 wt.% of CI particles in silicone oil and adding different proportions (0, 1, 3, or 5 wt.%) of ND and MoS2 additives. Seven kinds of MRFs are made and tested using reciprocating friction and wear tester under different normal loads, and then the friction characteristics are evaluated by analyzing the experimental results. The morphological properties of MRFs and contacting surfaces before and after the tests are also observed using a scanning electron microscope and analyzed via energy-dispersive X-ray spectroscopy. The results show that the appropriate weight percentage of MoS2 additives may decrease the friction coefficient and wear zone. It is also demonstrated from detailed analyses of worn surfaces that the wear mechanism is influenced not only by additives, but also by the applied normal load and magnetic field strength.
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Affiliation(s)
- Songran Zhuang
- College of Information Science and Engineering, Northeastern University, Shenyang 110819, China;
| | - Yongbing Cao
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China;
| | - Wanli Song
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China;
| | - Peng Zhang
- Nanjing Research Institute for Agricultural Mechanization, Ministry of Agriculture and Rural Affairs, Nanjing 210014, China;
| | - Seung-Bok Choi
- Department of Mechanical Engineering, The State University of New York, Korea (SUNY Korea), Incheon 21978, Republic of Korea
- Department of Mechanical Engineering, Industrial University of Ho Chi Minh City (IUH), Ho Chi Minh City 70000, Vietnam
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Hadło K, Lubas J, Szczypinski-Sala W, Tomala A, Konieczny D. Tribological Properties of a Sliding Joint with an a-C:H:W Coating under Lubrication Conditions with PAO8 Oil and the Addition of 2% MoS 2 Nanoparticles. Materials (Basel) 2024; 17:870. [PMID: 38399121 PMCID: PMC10890245 DOI: 10.3390/ma17040870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024]
Abstract
One of the promising methods for improving the durability and reliability of friction joints in combustion engines is the use of thin and hard coatings, including coatings based on amorphous DLC. The a-C:H:W coating was produced using the commercial PVD method. The tested tribological joints were made of AISI 4337 steel and SAE-48 bearing alloy (conformal contact) and AISI 4337 steel and valve shims (non-conformal contact). The contact area was lubricated with SAE 5W40 engine oil and PAO8 oil + 2 wt.% MoS2 nanoparticles. The objective of this work is to explore the influence of PAO8 + MoS2 on the tribological properties of a sliding joint with an a-C:H:W coating and the change in the properties of the oils. In the conformal contact, the lubrication of the a-C:H:W coating with PAO8 + MoS2 caused a significant increase in the friction resistance (than in) as compared to the joints with a quenching and tempering surface layer and lubricated SAE 5W40, while in the non-conformal contact, the lubrication of the a-C:H:W coating with PAO8 + MoS2 caused a decrease in the friction resistance and temperature of the contact area. The joints with the a-C:H:W coating were characterized by higher wear of the SAE-48 bearing alloy, as compared to the joints with the surface layer without coating (lubricated with SAE 5W40 oil-11-fold increase, PAO8 + MoS2-46-fold increase). The wear of valve shims with the a-C:H:W coating was significantly lower as compared to the wear of the commercial version of the valve shims (the difference between joints lubricated with SAE 5W40 oil and PAO8 + MoS2 was 12%, 36% and 29% for unit pressures of 10, 15 and 20 MPa). Lubrication of the a-C:H:W coating with PAO8 oil + MoS2 protected the sliding joints against seizing in non-conformal contact.
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Affiliation(s)
- Krystian Hadło
- Faculty of Mechanical Engineering and Aeronautics, Rzeszow University of Technology, Powstańców Warszawy 8 Av., 35-959 Rzeszow, Poland; (K.H.); (D.K.)
| | - Janusz Lubas
- Faculty of Mechanical Engineering and Aeronautics, Rzeszow University of Technology, Powstańców Warszawy 8 Av., 35-959 Rzeszow, Poland; (K.H.); (D.K.)
| | - Wojciech Szczypinski-Sala
- Faculty of Mechanical Engineering, Cracow University of Technology, 37 Jana Pawła II Av., 31-864 Krakow, Poland;
| | - Agnieszka Tomala
- Faculty of Materials Engineering and Physics, Cracow University of Technology, 37 Jana Pawła II Av., 31-864 Krakow, Poland;
| | - Dariusz Konieczny
- Faculty of Mechanical Engineering and Aeronautics, Rzeszow University of Technology, Powstańców Warszawy 8 Av., 35-959 Rzeszow, Poland; (K.H.); (D.K.)
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Sabik A, Ellis J, Hedgeland H, Ward DJ, Jardine AP, Allison W, Antczak G, Tamtögl A. Single-molecular diffusivity and long jumps of large organic molecules: CoPc on Ag(100). Front Chem 2024; 12:1355350. [PMID: 38380395 PMCID: PMC10876995 DOI: 10.3389/fchem.2024.1355350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
Energy dissipation and the transfer rate of adsorbed molecules do not only determine the rates of chemical reactions but are also a key factor that often dictates the growth of organic thin films. Here, we present a study of the surface dynamical motion of cobalt phthalocyanine (CoPc) on Ag(100) in reciprocal space based on the helium spin-echo technique in comparison with previous scanning tunnelling microscopy studies. It is found that the activation energy for lateral diffusion changes from 150 meV at 45-50 K to ≈100 meV at 250-350 K, and that the process goes from exclusively single jumps at low temperatures to predominantly long jumps at high temperatures. We thus illustrate that while the general diffusion mechanism remains similar, upon comparing the diffusion process over widely divergent time scales, indeed different jump distributions and a decrease of the effective diffusion barrier are found. Hence a precise molecular-level understanding of dynamical processes and thin film formation requires following the dynamics over the entire temperature scale relevant to the process. Furthermore, we determine the diffusion coefficient and the atomic-scale friction of CoPc and establish that the molecular motion on Ag(100) corresponds to a low friction scenario as a consequence of the additional molecular degrees of freedom.
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Affiliation(s)
- Agata Sabik
- Institute of Experimental Physics, University of Wrocław, Wrocław, Poland
- Department of Semiconductor Materials Engineering, Wrocław University of Science and Technology, Wrocław, Poland
| | - John Ellis
- Cavendish Laboratory, Cambridge, United Kingdom
| | | | | | | | | | - Grażyna Antczak
- Institute of Experimental Physics, University of Wrocław, Wrocław, Poland
| | - Anton Tamtögl
- Institute of Experimental Physics, Graz University of Technology, Graz, Austria
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15
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Chakraborty S, Moufti MA, Kheder W. The Effect of Dental Implant Drills Materials on Heat Generation in Osteotomy Sites: A Systematic Review. Eur J Dent 2024; 18:65-72. [PMID: 37336484 PMCID: PMC10959590 DOI: 10.1055/s-0043-1768472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023] Open
Abstract
The aim of this review was to examine the impact of dental implant drill materials and wear profiles on heat generation in the osteotomy sites as reported in experimental studies and to critically appraise these studies. The research question was formulated based on predefined patient, intervention, comparison, and outcome (PICO) elements. A comprehensive electronic search was undertaken in Medline/PubMed Central, Science Direct, and Google Scholar, using predetermined keywords, followed by a manual search of the bibliography of the selected articles. The selection of the studies for the critical appraisal part of our study was based on the criteria used to assess the study designs such as study aims, outcome measure, clarity of method, sample selection, randomization, allocation concealment, sample attrition, bias, method of data analysis, and external validity. Increased heat generation was observed with both ceramic and metal drills; the heat generation was proportional to drills' wear. The literature was inconclusive regarding the association between drill material and heat generation. However, drill materials had a significant influence on the overall temperature increase during osteotomy. The noncoated drills showed a higher wear resistance, and it has been observed that using worn drills leads to more friction contact, reduced drill cutting efficiency, and increased heat generation. Eleven in vitro studies met the inclusion criteria, and showed a considerable methodological heterogeneity and confounding factors, including drill geometry, speed and load, depth and diameter, number of uses, irrigation protocol, study specimens, and the heat measuring device. Besides, most of the studies have a potential operator and assessor bias, and some have sponsorship bias. It is possible to conclude that the literature is not conclusive on the effect of drill materials on heat generation during osteotomy. Lack of standardization and uniformity in the study design, along with potential bias in the study methodology can be the reason for the heterogeneity of the results.
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Affiliation(s)
| | - Mohammad-Adel Moufti
- Department of Preventive and Restorative Dentistry, College of Dental Medicine University of Sharjah, Sharjah, United Arab Emirates
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Waad Kheder
- Department of Preventive and Restorative Dentistry, College of Dental Medicine University of Sharjah, Sharjah, United Arab Emirates
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
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16
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Kohta M, Yunoki S, Sugama J. Effect of prophylactic dressings to reduce pressure injuries: a polymer-based skin model. J Wound Care 2024; 33:S4-S9. [PMID: 38348862 DOI: 10.12968/jowc.2024.33.sup2.s4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
OBJECTIVE This study evaluated the effect of pressure injury (PI) prophylactic dressings used for patients at high risk of PI development to reduce friction, shear force and pressure, and their combined force, in an original polymer-based skin model. METHOD A low-friction outer-layer hydrocolloid (LFH) dressing and a multilayered silicone foam (MSF) dressing were used. Before application, compression and friction properties were measured. Our original experimental model-the 'simulated skin-shearing test'-consisted of: a weight; a polyurethane-based skin model containing a three-axis tactile sensor; dressings; a table covered with bedsheets; and a mechanical tester, by which the interface friction force, internal shear force and pressure were measured continuously during skin model movements. An estimated combined force generated by internal shear and pressure was represented as a vector. A model with no dressing was used as a control. RESULTS The LFH dressing had significantly higher compression strength versus the MSF dressing. In contrast, the dynamic coefficient of friction was lower for the LFH dressing versus the MSF dressing (p<0.05). In simulated skin-shearing test results, shear forces were 0.45N and 0.42N for LFH and MSF dressings, respectively, with no significant difference. The estimated combined force was lower for the MSF dressing compared with that of the LFH dressing and control. CONCLUSION The shear force-reducing effect in the skin model was equivalent between the LFH and MSF dressings. However, the MSF dressing significantly reduced the force generated by a combination of internal shear force and pressure compared with the LFH dressing.
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Affiliation(s)
- Masushi Kohta
- Research Center for Implementation Nursing Science Initiative, School of Health Sciences, Fujita Health University, Aichi, Japan
| | - Shunji Yunoki
- Biotechnology Group, Tokyo Metropolitan Industrial Technology Research Institute, Tokyo, Japan
| | - Junko Sugama
- Research Center for Implementation Nursing Science Initiative, School of Health Sciences, Fujita Health University, Aichi, Japan
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17
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Park JE, Je H, Kim CR, Park S, Yu Y, Cho W, Won S, Kang DJ, Han TH, Kwak R, Lee SG, Kim S, Wie JJ. Programming Anisotropic Functionality of 3D Microdenticles by Staggered-Overlapped and Multilayered Microarchitectures. Adv Mater 2024; 36:e2309518. [PMID: 38014492 DOI: 10.1002/adma.202309518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/10/2023] [Indexed: 11/29/2023]
Abstract
Natural sharkskin features staggered-overlapped and multilayered architectures of riblet-textured anisotropic microdenticles, exhibiting drag reduction and providing a flexible yet strong armor. However, the artificial fabrication of three-dimensional (3D) sharkskin with these unique functionalities and mechanical integrity is a challenge using conventional techniques. In this study, it is reported on the facile microfabrication of multilayered 3D sharkskin through the magnetic actuation of polymeric composites and subsequent chemical shape fixation by casting thin polymeric films. The fabricated hydrophobic sharkskin, with geometric symmetry breaking, achieves anisotropic drag reduction in frontal and backward flow directions against the riblet-textured microdenticles. For mechanical integrity, hard-on-soft multilayered mechanical properties are realized by coating the polymeric sharkskin with thin layers of zinc oxide and platinum, which have higher hardness and recovery behaviors than the polymer. This multilayered hard-on-soft sharkskin exhibits friction anisotropy, mechanical robustness, and structural recovery. Furthermore, coating the MXene nanosheets provides the fabricated sharkskin with a low electrical resistance of ≈5.3 Ω, which leads to high Joule heating (≈229.9 °C at 2.75 V). The proposed magnetomechanical actuation-assisted microfabrication strategy is expected to facilitate the development of devices requiring multifunctional microtextures.
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Affiliation(s)
- Jeong Eun Park
- Department of Organic and Nano Engineering, The Research Institute of Industrial Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Hyeongmin Je
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Chae Ryean Kim
- Department of Chemistry, University of Ulsan, Ulsan, 44610, Republic of Korea
| | - Sudong Park
- Department of Mechanical Convergence Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Yeonuk Yu
- Department of Mechanical Convergence Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Woongbi Cho
- Department of Organic and Nano Engineering, Human-Tech Convergence Program, Hanyang University, Seoul, 04763, Republic of Korea
| | - Sukyoung Won
- Department of Organic and Nano Engineering, The Research Institute of Industrial Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Dong Jun Kang
- Department of Organic and Nano Engineering, The Research Institute of Industrial Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Tae Hee Han
- Department of Organic and Nano Engineering, The Research Institute of Industrial Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Rhokyun Kwak
- Department of Mechanical Convergence Engineering, Institute of Nano Science and Technology, Hanyang University, Seoul, 04763, Republic of Korea
| | - Seung Goo Lee
- Department of Chemistry, University of Ulsan, Ulsan, 44610, Republic of Korea
| | - Sanha Kim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Jeong Jae Wie
- Department of Organic and Nano Engineering, Human-Tech Convergence Program, Department of Chemical Engineering, Institute of Nano Science and Technology, Hanyang University, Seoul, 04763, Republic of Korea
- Department of Chemical Engineering, The Michael M. Szwarc Polymer Research Institute, State University of New York College of Environmental Science and Forestry, Syracuse, NY, 13210, USA
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Zhang Y, Li J, Wang Y, Nie J, Wang C, Tian K, Ma M. Loading Mode-Induced Enhancement in Friction for Microscale Graphite/Hexagonal Boron Nitride Heterojunction. ACS Appl Mater Interfaces 2024; 16:5308-5315. [PMID: 38235683 DOI: 10.1021/acsami.3c16962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Classical friction laws traditionally assume that the friction between solid pairs remains constant with a given normal load. However, our study has unveiled a remarkable deviation from conventional wisdom. In this paper, we discovered that altering the loading mode of micro graphite flakes led to significant changes in the lateral friction under identical normal loads. By adding a cap onto a single graphite flake to disperse the normal load applied by an atomic force microscope (AFM) tip, we were able to distribute the concentrated force. Astonishingly, our results demonstrated a notable 4-7 times increase in friction as a consequence of load dispersion. Finite element analysis (FEA) further confirmed that the increase in compressive stress at the edges of the graphite flake, resulting from load dispersion, led to a significant increase in friction. This study underscores the critical role of the loading mode in microscale friction dynamics, challenging the prevailing notion that friction remains static with a given normal force. Importantly, our research sheds light on the potential for achieving macroscale structural superlubricity (SSL) by assembling microscale SSL graphite flakes by using a larger cap.
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Affiliation(s)
- Yize Zhang
- State Key Laboratory of Tribology in Advanced Equipment & Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
| | - Jiacheng Li
- State Key Laboratory of Tribology in Advanced Equipment & Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Yiran Wang
- State Key Laboratory of Tribology in Advanced Equipment & Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Jinhui Nie
- Institute of Superlubricity Technology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Chen Wang
- Laboratory of Advanced Energy Storage Materials & devices, Center for Advanced Materials & Biotechnology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Kaiwen Tian
- Institute of Superlubricity Technology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Ming Ma
- State Key Laboratory of Tribology in Advanced Equipment & Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
- Institute of Superlubricity Technology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
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Li Y, Wu B, Ouyang W, Liu Z, Wang W. Experimental Decoding and Tuning Electronic Friction of Si Nanotip Sliding on Graphene. Nano Lett 2024; 24:1130-1136. [PMID: 38252698 DOI: 10.1021/acs.nanolett.3c03642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Due to the coupled contributions of adhesion and carrier to friction typically found in previous research, decoupling the electron-based dissipation is a long-standing challenge in tribology. In this study, by designing and integrating a graphene/h-BN/graphene/h-BN stacking device into an atomic force microscopy, the carrier density dependent frictional behavior of a single-asperity sliding on graphene is unambiguously revealed by applying an external back-gate voltage, while maintaining the adhesion unaffected. Our experiments reveal that friction on the graphene increases monotonically with the increase of carrier density. By adjusting the back-gate voltage, the carrier density of the top graphene layer can be tuned from -3.9 × 1012 to 3.5 × 1012 cm-2, resulting in a ∼28% increase in friction. The mechanism is uncovered from the consistent dependence of the charge density redistribution and sliding barrier on the carrier density. These findings offer new perspectives on the fundamental understanding and regulation of friction at van der Waals interfaces.
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Affiliation(s)
- Yutao Li
- School of Mechanical Engineering, Southwest Jiaotong University, 610031 Chengdu, China
| | - Bozhao Wu
- Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China
| | - Wengen Ouyang
- Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China
| | - Ze Liu
- Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China
| | - Wen Wang
- School of Mechanical Engineering, Southwest Jiaotong University, 610031 Chengdu, China
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20
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Pole M, Man K, Mahajan C, Jha S, Yang Y, Mukherjee S. Biocompatible Co-P Metallic Glasses with Superior Degradation Tolerance in Physiological Environments. ACS Appl Bio Mater 2024; 7:238-245. [PMID: 38153976 DOI: 10.1021/acsabm.3c00844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2023]
Abstract
Metallic glasses represent a class of metallic alloys with a fully amorphous structure and attractive properties, making them promising in bioimplant applications. Here, the degradation tolerance of biocompatible cobalt-phosphorus (Co-P) metallic glasses was studied in a simulated physiological environment. The metallic glasses were synthesized in the form of coatings through a facile electrodeposition approach. This method utilizes their outstanding surface characteristics and bypasses the size limitations usually associated with their bulk counterparts. The Co-P alloys showed exceptional tribological response with ∼14% lower coefficient of friction and 2 orders of magnitude lesser wear rate compared to SS316 stainless steel. In addition, the Co-P alloys showed a 3 times higher hardness and 4 times higher hardness/modulus ratio compared to SS316, indicating better elastic recovery under dynamic shear stresses that are common in load-bearing bioimplants. The Co-P metallic glasses exhibited excellent hemocompatibility and cytocompatibility in terms of lower platelet adhesion, spreading, and aggregation, a hemolysis ratio lower than 1%, and enhanced surface wettability, suggesting a superlative performance in bioimplant applications.
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Affiliation(s)
- Mayur Pole
- Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, United States
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Kun Man
- Department of Biomedical Engineering, University of North Texas, Denton, Texas 76203, United States
| | - Chaitanya Mahajan
- Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, United States
| | - Shristy Jha
- Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, United States
| | - Yong Yang
- Department of Biomedical Engineering, University of North Texas, Denton, Texas 76203, United States
| | - Sundeep Mukherjee
- Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, United States
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Sakata Y, Mayama H, Nonomura Y. Friction Dynamics of Human Skin Treated with Oil under Nonlinear Motion. J Oleo Sci 2024; 73:177-186. [PMID: 38311408 DOI: 10.5650/jos.ess23166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024] Open
Abstract
Moisturization causes physiological changes that improve the barrier function of human skin and mechanical changes, including skin friction characteristics. This study evaluated petrolatum- or silicone oil-treated human skin to determine the effect of moisturizing on the friction dynamics. The friction force on the human skin was measured using a contact probe with a sinusoidal motion. The contact probe was used to rub the skin of the upper arm of 20 subjects. The water content of the stratum corneum, softness, and barrier function of the skin were measured using a corneometer, cutometer, and tewameter, respectively. Both oils reduce the frictional force on the human skin. Simultaneously, silicone oil also reduced the delay time δ, which is the standardized time difference between the frictional force response to contact probe movement. Three typical friction patterns were also discovered, which were significantly changed by the treatment with oil. These changes were attributed to the lubrication effect and elimination of adhesion at the true contact point between the skin and the contact probe.
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Affiliation(s)
- Yuka Sakata
- Department of Applied Chemistry, Chemical Engineering, and Biochemical Engineering, Graduate School of Science and Engineering, Yamagata University
| | | | - Yoshimune Nonomura
- Department of Applied Chemistry, Chemical Engineering, and Biochemical Engineering, Graduate School of Science and Engineering, Yamagata University
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22
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Ptak A, Łuksza Z. Using Standstill Time to Evaluate the Startup in Polymer Pair Systems. Polymers (Basel) 2023; 15:4696. [PMID: 38139948 PMCID: PMC10746984 DOI: 10.3390/polym15244696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 11/30/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
The subject of polymer-polymer pair interaction is highly important, bearing in mind that such pairs are used in the construction of machines and equipment, among other uses. Considering that the characteristics of polymer-polymer sliding pairs (e.g., the load limit value and advantageous parameter, PV) differ from those of polymer-metal pairs, the subject is particularly interesting and has been little explored so far. Hence, the present study presents one of the areas of the effects of standstill time (intrinsically characteristic of polymeric materials) on the startup parameters in sliding pairs where the sample and the countersample were made of a polymeric material. Pairs of same-type polymers, POM-POM, PET-PET, and PA6-PA6, were subjected to tests. A test rig dedicated to static friction coefficient determination, whose principle of operation is based on the interdependences between the force characteristics of an inclined plane, was used for this purpose. The sliding pair was successively loaded with 25 N, 50 N, and 75 N, and the standstill time ranged from 0 to 10 min. The determined tribological characteristics were analysed with regard to the standstill time under load, unit pressure, and polymer pair material. An optical profilometer and a scanning electron microscope were used to qualitatively evaluate the effects of standstill time and unit pressure on the surfaces of the interacting elements. Complex interrelationships between the test results and the set experimental parameters were noted. SEM micrographs revealed post-friction changes in the sliding surfaces.
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Affiliation(s)
- Anita Ptak
- Department of Fundamentals of Machine Design and Mechatronic Systems, Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, ul. I. Lukasiewicza 5, 50-371 Wroclaw, Poland;
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23
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Shoyer TC, Gates EM, Cabe JI, Urs AN, Conway DE, Hoffman BD. Coupling during collective cell migration is controlled by a vinculin mechanochemical switch. Proc Natl Acad Sci U S A 2023; 120:e2316456120. [PMID: 38055737 PMCID: PMC10722971 DOI: 10.1073/pnas.2316456120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 10/24/2023] [Indexed: 12/08/2023] Open
Abstract
The ability of cells to move in a mechanically coupled, coordinated manner, referred to as collective cell migration, is central to many developmental, physiological, and pathophysiological processes. Limited understanding of how mechanical forces and biochemical regulation interact to affect coupling has been a major obstacle to unravelling the underlying mechanisms. Focusing on the linker protein vinculin, we use a suite of Förster resonance energy transfer-based biosensors to probe its mechanical functions and biochemical regulation, revealing a switch that toggles vinculin between loadable and unloadable states. Perturbation of the switch causes covarying changes in cell speed and coordination, suggesting alteration of the friction within the system. Molecular scale modelling reveals that increasing levels of loadable vinculin increases friction, due to engagement of self-stabilizing catch bonds. Together, this work reveals a regulatory switch for controlling cell coupling and describes a paradigm for relating biochemical regulation, altered mechanical properties, and changes in cell behaviors.
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Affiliation(s)
- T. Curtis Shoyer
- Department of Biomedical Engineering, Duke University, Durham, NC27708
| | - Evan M. Gates
- Department of Biomedical Engineering, Duke University, Durham, NC27708
| | - Jolene I. Cabe
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA23284
| | - Aarti N. Urs
- Department of Cell Biology, Duke University, Durham, NC27710
| | - Daniel E. Conway
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH43210
| | - Brenton D. Hoffman
- Department of Biomedical Engineering, Duke University, Durham, NC27708
- Department of Cell Biology, Duke University, Durham, NC27710
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24
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Wen HC, Wu SK, Liu CW, Dai JJ, Chou WC. Nanotribological Characteristics of the Al Content of Al xGa 1-xN Epitaxial Films. Nanomaterials (Basel) 2023; 13:2884. [PMID: 37947729 PMCID: PMC10650391 DOI: 10.3390/nano13212884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/16/2023] [Accepted: 10/25/2023] [Indexed: 11/12/2023]
Abstract
The nanotribological properties of aluminum gallium nitride (AlxGa1-xN) epitaxial films grown on low-temperature-grown GaN/AlN/Si substrates were investigated using a nanoscratch system. It was confirmed that the Al compositions played an important role, which was directly influencing the strength of the bonding forces and the shear resistance. It was verified that the measured friction coefficient (μ) values of the AlxGa1-xN films from the Al compositions (where x = 0.065, 0.085, and 0.137) were in the range of 0.8, 0.5, and 0.3, respectively, for Fn = 2000 μN and 0.12, 0.9, and 0.7, respectively, for Fn = 4000 μN. The values of μ were found to decrease with the increases in the Al compositions. We concluded that the Al composition played an important role in the reconstruction of the crystallites, which induced the transition phenomenon of brittleness to ductility in the AlxGa1-xN system.
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Affiliation(s)
- Hua-Chiang Wen
- Department of Electrophysics, College of Sciences, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan; (S.-K.W.); (C.-W.L.); (J.-J.D.)
| | | | | | | | - Wu-Ching Chou
- Department of Electrophysics, College of Sciences, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan; (S.-K.W.); (C.-W.L.); (J.-J.D.)
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25
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Borrego M, Kuhn E, Martín-Alfonso JE, Franco JM. Assessment of the Tribological Performance of Electrospun Lignin Nanofibrous Web-Thickened Bio-Based Greases in a Nanotribometer. Nanomaterials (Basel) 2023; 13:2852. [PMID: 37947697 PMCID: PMC10649236 DOI: 10.3390/nano13212852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/16/2023] [Accepted: 10/26/2023] [Indexed: 11/12/2023]
Abstract
The tribological performance of novel bio-based lubricating greases thickened with electrospun lignin nanostructures was investigated in a nanotribometer using a steel-steel ball-on-disc configuration. The impact of electrospun nanofibrous network morphology on friction and wear is explored in this work. Different lignin nanostructures were obtained with electrospinning using ethylcellulose or PVP as co-spinning polymers and subsequently used as thickeners in castor oil at concentrations of 10-30% wt. Friction and wear generally increased with thickener concentration. However, friction and wear decreased when using homogeneous bead-free nanofiber mats (with higher fiber diameter and lower porosity) rather than nanostructures dominated by the presence of particles or beaded fibers, which was favored by reducing the lignin:co-spinning polymer ratio.
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Affiliation(s)
- María Borrego
- Chemical Product and Process Technology Research Center (Pro2TecS), Department Chemical Engineering and Materials Science, Escuela Técnica Superior de Ingeniería (ETSI), Campus de “El Carmen”, University of Huelva, 21071 Huelva, Spain; (M.B.); (J.E.M.-A.)
| | - Erik Kuhn
- Laboratory of Machine Elements and Tribology, Department of Mechanical Engineering and Production, Faculty of Engineering Technology and Computer Science, Hamburg University of Applied Sciences (HAW-Hamburg), Berliner Tor 21, 20099 Hamburg, Germany;
| | - José E. Martín-Alfonso
- Chemical Product and Process Technology Research Center (Pro2TecS), Department Chemical Engineering and Materials Science, Escuela Técnica Superior de Ingeniería (ETSI), Campus de “El Carmen”, University of Huelva, 21071 Huelva, Spain; (M.B.); (J.E.M.-A.)
| | - José M. Franco
- Chemical Product and Process Technology Research Center (Pro2TecS), Department Chemical Engineering and Materials Science, Escuela Técnica Superior de Ingeniería (ETSI), Campus de “El Carmen”, University of Huelva, 21071 Huelva, Spain; (M.B.); (J.E.M.-A.)
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26
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Sahoo S, Khan Z, Mannan S, Tiwari U, Ye Z, Krishnan NMA, Gosvami NN. Superlubricity and Stress-Shielding of Graphene Enables Ultra Scratch-Resistant Glasses. ACS Appl Mater Interfaces 2023. [PMID: 37886825 DOI: 10.1021/acsami.3c09653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Glasses, when subjected to scratch loading, incur damages affecting their optical and mechanical integrity. Here, it is demonstrated that silica glasses protected with mechanically exfoliated few-layer graphene sheets can exhibit remarkable improvement in scratch resistance. To this extent, the friction and wear characteristics of silica glasses with exfoliated graphene using atomic force microscopy (AFM) are explored. The friction forces recorded during AFM scratch tests of the graphene-glass surfaces at multiple loads exhibit ∼98% reduction compared to that of the bare silica glass, with the friction coefficient falling in the superlubricity regime. This dramatic reduction in friction achieved by the graphene sheets results in significantly lower wear of the graphene-glass surfaces postscratching. Further investigations employing atomistic simulations reveal that the stress-shielding mechanism is due to the reduced deformation of graphene-glass surfaces, thereby curtailing the overall damage. Altogether, the present work provides a new fillip toward the development of glasses with enhanced scratch resistance exploiting two-dimensional coatings.
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Affiliation(s)
- Sourav Sahoo
- Department of Materials Science and Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Zuhaa Khan
- Department of Materials Science and Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
- Department of Metallurgical and Materials Engineering, National Institute of Technology, Srinagar 190006, India
| | - Sajid Mannan
- Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Utkarsh Tiwari
- Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Zhijiang Ye
- Department of Mechanical and Manufacturing Engineering, Miami University, Oxford, Ohio 45056, United States
| | - N M Anoop Krishnan
- Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
- Yardi School of Artificial Intelligence, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Nitya Nand Gosvami
- Department of Materials Science and Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
- Yardi School of Artificial Intelligence, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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Wu Z, Tan X, Li G, Xing Y. Tribological Properties of Groove-Textured Ti-6Al-4V Alloys with Solid Lubricants in Dry Sliding against GCr15 Steel Balls. Micromachines (Basel) 2023; 14:1978. [PMID: 38004835 PMCID: PMC10673546 DOI: 10.3390/mi14111978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/12/2023] [Accepted: 10/24/2023] [Indexed: 11/26/2023]
Abstract
A nanosecond laser is used to fabricate groove-patterned textures on the upper surface of Ti-6Al-4V alloys, and then molybdic sulfide solid lubricants are filled into the grooves. The treated titanium alloy is subjected to friction and wear tests. The tribological performances of Ti-6Al-4V alloys are evaluated, and the wearing mechanism is analyzed. The combination of solid lubricants and surface texturing can effectively reduce the frictional coefficient and reduce the adhesion of Ti-6Al-4V materials on the steel balls for friction. The main wearing mechanism is the adhesive wear of the Ti-6Al-4V alloy and the adhesion of Ti-6Al-4V alloy materials on the surface of the steel balls. During the friction process, solid lubricants are squeezed from the grooves and coated at the friction interface to form a solid lubrication layer. This is the important reason why the combination of surface texturing and solid lubricants can improve the friction properties of titanium alloys effectively. The combination of solid lubricants and laser surface texturing provides an effective alternative way to improve the tribological properties of titanium alloy materials.
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Affiliation(s)
- Ze Wu
- School of Mechanical Engineering, Southeast University, Nanjing 211189, China (Y.X.)
| | - Xiuli Tan
- School of Mechanical Engineering, Southeast University, Nanjing 211189, China (Y.X.)
| | - Guochao Li
- School of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China
| | - Youqiang Xing
- School of Mechanical Engineering, Southeast University, Nanjing 211189, China (Y.X.)
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28
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Mohammed AJ, Mohammed AS, Mohammed AS. Prediction of Tribological Properties of UHMWPE/SiC Polymer Composites Using Machine Learning Techniques. Polymers (Basel) 2023; 15:4057. [PMID: 37896301 PMCID: PMC10610110 DOI: 10.3390/polym15204057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/03/2023] [Accepted: 10/08/2023] [Indexed: 10/29/2023] Open
Abstract
Polymer composites are a class of material that are gaining a lot of attention in demanding tribological applications due to the ability of manipulating their performance by changing various factors, such as processing parameters, types of fillers, and operational parameters. Hence, a number of samples under different conditions need to be repeatedly produced and tested in order to satisfy the requirements of an application. However, with the advent of a new field of triboinformatics, which is a scientific discipline involving computer technology to collect, store, analyze, and evaluate tribological properties, we presently have access to a variety of high-end tools, such as various machine learning (ML) techniques, which can significantly aid in efficiently gauging the polymer's characteristics without the need to invest time and money in a physical experimentation. The development of an accurate model specifically for predicting the properties of the composite would not only cheapen the process of product testing, but also bolster the production rates of a very strong polymer combination. Hence, in the current study, the performance of five different machine learning (ML) techniques is evaluated for accurately predicting the tribological properties of ultrahigh molecular-weight polyethylene (UHMWPE) polymer composites reinforced with silicon carbide (SiC) nanoparticles. Three input parameters, namely, the applied pressure, holding time, and the concentration of SiCs, are considered with the specific wear rate (SWR) and coefficient of friction (COF) as the two output parameters. The five techniques used are support vector machines (SVMs), decision trees (DTs), random forests (RFs), k-nearest neighbors (KNNs), and artificial neural networks (ANNs). Three evaluation statistical metrics, namely, the coefficient of determination (R2-value), mean absolute error (MAE), and root mean square error (RMSE), are used to evaluate and compare the performances of the different ML techniques. Based upon the experimental dataset, the SVM technique was observed to yield the lowest error rates-with the RMSE being 2.09 × 10-4 and MAE being 2 × 10-4 for COF and for SWR, an RMSE of 2 × 10-4 and MAE of 1.6 × 10-4 were obtained-and highest R2-values of 0.9999 for COF and 0.9998 for SWR. The observed performance metrics shows the SVM as the most reliable technique in predicting the tribological properties-with an accuracy of 99.99% for COF and 99.98% for SWR-of the polymer composites.
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Affiliation(s)
- Abdul Jawad Mohammed
- Department of Information and Computer Science, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia;
| | | | - Abdul Samad Mohammed
- Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
- Interdisciplinary Research Center for Advanced Materials, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
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Ilyina SO, Gorbunova IY, Makarova VV, Kerber ML, Ilyin SO. Self-Lubricating and Shape-Stable Phase-Change Materials Based on Epoxy Resin and Vegetable Oils. Polymers (Basel) 2023; 15:4026. [PMID: 37836075 PMCID: PMC10575338 DOI: 10.3390/polym15194026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/26/2023] [Accepted: 10/07/2023] [Indexed: 10/15/2023] Open
Abstract
Palm or coconut oil is capable of dissolving in a mixture of bisphenol A-based epoxy resin and a high-temperature hardener (4,4'-diaminodiphenyl sulfone) when heated and then forms a dispersed phase as a result of cross-linking and molecular weight growth of the epoxy medium. Achieving the temporary miscibility between the curing epoxy matrix and the vegetable oil allows a uniform distribution of vegetable oil droplets in the epoxy medium. This novel approach to creating a dispersed phase-change material made a cured epoxy polymer containing up to 20% oil. The miscibility of epoxy resin and oil was studied by laser interferometry, and phase state diagrams of binary mixtures were calculated according to theory and experiments. A weak effect of oil on the viscosity and kinetics of the epoxy resin curing was demonstrated by rotational rheometry. According to differential scanning calorimetry and dynamic mechanical analysis, the oil plasticizes the epoxy matrix slightly, expanding its glass transition region towards low temperatures and reducing its elastic modulus. In the cured epoxy matrix, oil droplets have a diameter of 3-14 µm and are incapable of complete crystallization due to their multi-component chemical composition and non-disappeared limited miscibility. The obtained phase-change materials have relatively low specific energy capacity but can be used alternatively as self-lubricating low-noise materials due to dispersed oil, high stiffness, and reduced friction coefficient. Palm oil crystallizes more readily, better matching the creation of phase-change materials, whereas coconut oil crystallization is more suppressed, making it better for reducing the friction coefficient of the oil-containing material.
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Affiliation(s)
- Svetlana O. Ilyina
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninsky Prospect, 119991 Moscow, Russia
- Department of Plastics Processing Technology, D. Mendeleev University of Chemical Technology of Russia, 9 Miusskaya Square, 125047 Moscow, Russia
| | - Irina Y. Gorbunova
- Department of Plastics Processing Technology, D. Mendeleev University of Chemical Technology of Russia, 9 Miusskaya Square, 125047 Moscow, Russia
| | - Veronika V. Makarova
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninsky Prospect, 119991 Moscow, Russia
| | - Michael L. Kerber
- Department of Plastics Processing Technology, D. Mendeleev University of Chemical Technology of Russia, 9 Miusskaya Square, 125047 Moscow, Russia
| | - Sergey O. Ilyin
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninsky Prospect, 119991 Moscow, Russia
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30
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Lyashenko IA, Popov VL, Borysiuk V. Indentation and Detachment in Adhesive Contacts between Soft Elastomer and Rigid Indenter at Simultaneous Motion in Normal and Tangential Direction: Experiments and Simulations. Biomimetics (Basel) 2023; 8:477. [PMID: 37887608 PMCID: PMC10603904 DOI: 10.3390/biomimetics8060477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 10/28/2023] Open
Abstract
In reported experiments, a steel indenter was pressed into a soft elastomer layer under varying inclination angles and subsequently was detached under various inclination angles too. The processes of indentation and detachment were recorded with a video camera, and the time dependences of the normal and tangential components of the contact force and the contact area, as well as the average contact pressure and average tangential stresses, were measured as functions of the inclination angle. Based on experimental results, a simple theoretical model of the indentation process is proposed, in which tangential and normal contacts are considered independently. Both experimental and theoretical results show that at small indentation angles (when the direction of motion is close to tangential), a mode with elastomer slippage relative to the indenter is observed, which leads to complex dynamic processes-the rearrangement of the contact boundary and the propagation of elastic waves (similar to Schallamach waves). If the angle is close to the normal angle, there is no slipping in the contact plane during the entire indentation (detachment) phase.
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Affiliation(s)
- Iakov A. Lyashenko
- Department of System Dynamics and Friction Physics, Institute of Mechanics, Technische Universität Berlin, 10623 Berlin, Germany; (V.L.P.); (V.B.)
- Department of Applied Mathematics and Complex Systems Modeling, Faculty of Electronics and Information Technology, Sumy State University, 40007 Sumy, Ukraine
| | - Valentin L. Popov
- Department of System Dynamics and Friction Physics, Institute of Mechanics, Technische Universität Berlin, 10623 Berlin, Germany; (V.L.P.); (V.B.)
| | - Vadym Borysiuk
- Department of System Dynamics and Friction Physics, Institute of Mechanics, Technische Universität Berlin, 10623 Berlin, Germany; (V.L.P.); (V.B.)
- Department of Nanoelectronics and Surface Modification, Faculty of Electronics and Information Technology, Sumy State University, 40007 Sumy, Ukraine
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31
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Motuzas CA, Shcherbakov R. Viscoelastic Slider Blocks as a Model for a Seismogenic Fault. Entropy (Basel) 2023; 25:1419. [PMID: 37895540 PMCID: PMC10606542 DOI: 10.3390/e25101419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/29/2023]
Abstract
In this work, a model is proposed to examine the role of viscoelasticity in the generation of simulated earthquake-like events. This model serves to investigate how nonlinear processes in the Earth's crust affect the triggering and decay patterns of earthquake sequences. These synthetic earthquake events are numerically simulated using a slider-block model containing viscoelastic standard linear solid (SLS) elements to reproduce the dynamics of an earthquake fault. The simulated system exhibits elements of self-organized criticality, and results in the generation of avalanches that behave similarly to naturally occurring seismic events. The model behavior is analyzed using the Epidemic-Type Aftershock Sequence (ETAS) model, which suitably represents the observed triggering and decay patterns; however, parameter estimates deviate from those resulting from natural aftershock sequences. Simulated aftershock sequences from this model are characterized by slightly larger p-values, indicating a faster-than-normal decay of aftershock rates within the system. The ETAS fit, along with realistic simulated frequency-size distributions, supports the inclusion of viscoelastic rheology to model the seismogenic fault dynamics.
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Affiliation(s)
- Charlotte A. Motuzas
- Department of Earth Sciences, Western University, London, ON N6A 5B7, Canada
- Department of Physics and Astronomy, Western University, London, ON N6A 3K7, Canada
| | - Robert Shcherbakov
- Department of Earth Sciences, Western University, London, ON N6A 5B7, Canada
- Department of Physics and Astronomy, Western University, London, ON N6A 3K7, Canada
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32
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Zhang X, Yao Z, Du H, Song J, Jin Z, Xu W. Wettability and Frictional Studies of PEEK Composites against Co-Cr Alloys with Surface Textures. Polymers (Basel) 2023; 15:4006. [PMID: 37836055 PMCID: PMC10574895 DOI: 10.3390/polym15194006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/22/2023] [Accepted: 10/05/2023] [Indexed: 10/15/2023] Open
Abstract
With the aim of promoting the qualities for total hip joint replacement, the wettability and tribological behaviors of PEEK composites pins with two sets of different fillers (PEEK/CF or PEEK/CF/PTFE/graphite) against Co-Cr alloy discs with five categories of surface textures (polished, orthogonal, spiral, r-θ, and orthogonal combined with spiral) were explored. It is revealed that the existence of CF in PEEK matrix increases the hydrophilicity in addition to the strength of PEEK, while the addition of PTFE increases the hydrophobicity of PEEK. The Co-Cr alloy discs with hydrophilic properties can be adjusted as hydrophobic, with the depth of textured grooves exceeding the critical sag height determined by the contact angle and the groove width. It can be concluded that PEEK/CF/PTFE/graphite composite has a lower wear rate than PEEK only reinforced with CF against Co-Cr alloy, both without surface texture and with shallow or deep grooves. The existence of shallow grooves on the disc surface could help the PEEK blends to achieve a steady friction against Co-Cr alloy in addition to collecting the worn debris. PEEK blend pins with 10 vol% CF, 10 vol% PTFE and 10 vol% graphite can achieve a lower friction coefficient of no more than 0.2 against Co-Cr alloy discs with shallow grooves around 3.5 μm in orthogonal or spiral textures.
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Affiliation(s)
- Xifang Zhang
- College of Smart Energy, Shanghai Jiao Tong University, Shanghai 200240, China; (X.Z.); (W.X.)
| | - Zhenqiang Yao
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (H.D.); (J.S.); (Z.J.)
- State Key Laboratory of Mechanical System and Vibration, Shanghai 200240, China
| | - Haifeng Du
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (H.D.); (J.S.); (Z.J.)
- State Key Laboratory of Mechanical System and Vibration, Shanghai 200240, China
| | - Jiacheng Song
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (H.D.); (J.S.); (Z.J.)
- State Key Laboratory of Mechanical System and Vibration, Shanghai 200240, China
| | - Zhiyi Jin
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (H.D.); (J.S.); (Z.J.)
- State Key Laboratory of Mechanical System and Vibration, Shanghai 200240, China
| | - Wei Xu
- College of Smart Energy, Shanghai Jiao Tong University, Shanghai 200240, China; (X.Z.); (W.X.)
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33
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Alevizakos V, Achilles N, Rahlf B, Jehn P, von See C, Schiller M. Comparing Original and Universal Screwdrivers and How They Affect Friction in the Screw. J ORAL IMPLANTOL 2023; 49:532-536. [PMID: 36893110 DOI: 10.1563/aaid-joi-d-20-00249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/05/2021] [Accepted: 09/21/2022] [Indexed: 03/10/2023]
Abstract
The present study focused on investigating whether universal screwdriver kits cause less friction between the screwdriver and the abutment screw than original screwdrivers. For this purpose, 2 original screwdrivers (Straumann and BEGO) and a universal screwdriver kit (bredent) were investigated. On 1 implant per screwdriver, 26 abutments were properly attached one after the other with the corresponding abutment screws. After tightening the abutment screw, the force required to pull the screwdriver off the screw head was determined with a spring balance. For both manufacturers, greater pull-off forces were measured when using the original screwdrivers than when using the universal screwdriver. The pull-off force (mean ± SD) required for the Straumann original screwdriver was 3.7 ± 1.4 N, while that required for the universal screwdriver was 0.1 ± 0.1 N (P < .001). The pull-off force was 1.5 ± 1.5 N for the BEGO original screwdriver and 0.7 ± 0.9 N for the universal screwdriver (P = .19). Using original manufacturer-supplied screwdrivers could thus minimize the risk of the screwdriver slipping out of the screw head during dental treatment and being swallowed or aspirated by the patient.
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Affiliation(s)
- Vasilios Alevizakos
- Research Center for Digital Technologies in Dentistry and CAD/CAM, Department of Dentistry, Faculty of Medicine and Dentistry, Danube Private University, Krems, Austria
| | - Nadine Achilles
- Hannover Medical School, Department of Oral and Maxillofacial Surgery, Hannover, Germany
| | - Björn Rahlf
- Hannover Medical School, Department of Oral and Maxillofacial Surgery, Hannover, Germany
| | - Philipp Jehn
- Hannover Medical School, Department of Oral and Maxillofacial Surgery, Hannover, Germany
| | - Constantin von See
- Research Center for Digital Technologies in Dentistry and CAD/CAM, Department of Dentistry, Faculty of Medicine and Dentistry, Danube Private University, Krems, Austria
| | - Marcus Schiller
- Hannover Medical School, Department of Oral and Maxillofacial Surgery, Hannover, Germany
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Acharya SR, Hutapea P. An experimental study on the mechanics and control of SMA-actuated bioinspired needle. Bioinspir Biomim 2023; 18:066008. [PMID: 37726011 DOI: 10.1088/1748-3190/acfb65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/19/2023] [Indexed: 09/21/2023]
Abstract
Active needles demonstrate improved accuracy and tip deflection compared to their passive needle counterparts, a crucial advantage in percutaneous procedures. However, the ability of these needles to effectively navigate through tissues is governed by needle-tissue interaction, which depends on the tip shape, the cannula surface geometry, and the needle insertion method. In this research, we evaluated the effect of cannula surface modifications and the application of a vibrational insertion technique on the performance of shape memory alloy (SMA)-actuated active needles. These features were inspired by the mosquito proboscis' unique design and skin-piercing technique that decreased the needle tissue interaction force, thus enhancing tip deflection and steering accuracy. The bioinspired features, i.e., mosquito-inspired cannula design and vibrational insertion method, in an active needle reduced the insertion force by 26.24% and increased the tip deflection by 37.11% in prostate-mimicking gel. In addition, trajectory tracking error was reduced by 48%, and control effort was reduced by 23.25%, pointing towards improved needle placement accuracy. The research highlights the promising potential of bioinspired SMA-actuated active needles. Better tracking control and increased tip deflection are anticipated, potentially leading to improved patient outcomes and minimized risk of complications during percutaneous procedures.
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Affiliation(s)
- Sharad Raj Acharya
- Department of Mechanical Engineering, Temple University, Philadelphia, PA, United States of America
| | - Parsaoran Hutapea
- Department of Mechanical Engineering, Temple University, Philadelphia, PA, United States of America
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35
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Wei Z, Han D, Wang Q, Sun C, Tao Y, Xiang L, Kan Y, Zhang Y, Lu X, Chen Y. Modulating Friction by the Phase of the Vertical Vibrational Excitation at Washboard Frequency. ACS Appl Mater Interfaces 2023; 15:45516-45525. [PMID: 37722024 DOI: 10.1021/acsami.3c11347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
Applying external vibrations at the resonant frequencies of the frictional system has been a highly effective approach to suppress friction but usually requires additional energy consumption. In this study, we find that in addition to exerting the vibration at the resonant frequency of the frictional system, the friction force on the atomically flat silicon surface can also present a local minimum when the oscillation frequency of the vertical vibrational excitation equals the washboard frequency with respect to the sliding velocity. Moreover, compared with the additional energy consumption at the resonant frequency, applying vertical vibrational excitation at the washboard frequency requires much less energy consumption. The study further shows that the friction force under the washboard frequency can be effectively mediated depending on how the initial phase angle of the vertical vibrational excitation affects the effective substrate potential barrier at the slip moment of the tip. We have also extended the proposed friction modulation technique on atomically flat surfaces to periodic textured surfaces and confirmed its practicality and great potential for controlling friction.
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Affiliation(s)
- Zhiyong Wei
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Dong Han
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Qi Wang
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Chengdong Sun
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Yi Tao
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Li Xiang
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Yajing Kan
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Yan Zhang
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Xi Lu
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Yunfei Chen
- Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments, Southeast University, Nanjing 211189, People's Republic of China
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
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Zhang L, Chen W, Tan X, Jiao J, Guo D, Luo J. Nonmonotonic Effects of Atomic Vacancy Defects on Friction. ACS Appl Mater Interfaces 2023; 15:45455-45464. [PMID: 37722023 DOI: 10.1021/acsami.3c09257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
The presence of defects such as vacancies has a significant impact on the frictional properties of 2D materials that are excellent solid lubricants. In this study, we demonstrate that the nonmonotonic effect of Te vacancy defects on the friction of MoTe2 is related to the change in the maximum sliding energy barrier due to the variation in tip position. The experimental results of atomic force microscopy suggest that the friction shows an overall increasing trend with the increase in Te vacancy density, but this variation is nonmonotonic. Molecular dynamics simulations show that the increase in friction force with defect density can be attributed to the large and more sliding energy barriers that the tip has to overcome. Furthermore, the nonmonotonic variation of friction with defect density is dominated by the change of the maximum sliding potential barrier caused by the variation of tip position perpendicular to the sliding direction during the sliding process. Additionally, the uneven charge distribution due to charge transfer occurring at the defect also contributes to the increase in friction. This work shows the mechanism of the effect of Te vacancy defects on the friction of MoTe2, which provides guidance for the modulation of the frictional properties of solid lubricants.
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Affiliation(s)
- Lina Zhang
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Weibin Chen
- School of Materials Science and Engineering, Peking University, Beijing 100084, China
| | - Xinfeng Tan
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Jianguo Jiao
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Dan Guo
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Jianbin Luo
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
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Colin A, Orhant-Prioux M, Guérin C, Savinov M, Cao W, Vianay B, Scarfone I, Roux A, De La Cruz EM, Mogilner A, Théry M, Blanchoin L. Friction patterns guide actin network contraction. Proc Natl Acad Sci U S A 2023; 120:e2300416120. [PMID: 37725653 PMCID: PMC10523593 DOI: 10.1073/pnas.2300416120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 08/09/2023] [Indexed: 09/21/2023] Open
Abstract
The shape of cells is the outcome of the balance of inner forces produced by the actomyosin network and the resistive forces produced by cell adhesion to their environment. The specific contributions of contractile, anchoring and friction forces to network deformation rate and orientation are difficult to disentangle in living cells where they influence each other. Here, we reconstituted contractile actomyosin networks in vitro to study specifically the role of the friction forces between the network and its anchoring substrate. To modulate the magnitude and spatial distribution of friction forces, we used glass or lipids surface micropatterning to control the initial shape of the network. We adapted the concentration of Nucleating Promoting Factor on each surface to induce the assembly of actin networks of similar densities and compare the deformation of the network toward the centroid of the pattern shape upon myosin-induced contraction. We found that actin network deformation was faster and more coordinated on lipid bilayers than on glass, showing the resistance of friction to network contraction. To further study the role of the spatial distribution of these friction forces, we designed heterogeneous micropatterns made of glass and lipids. The deformation upon contraction was no longer symmetric but biased toward the region of higher friction. Furthermore, we showed that the pattern of friction could robustly drive network contraction and dominate the contribution of asymmetric distributions of myosins. Therefore, we demonstrate that during contraction, both the active and resistive forces are essential to direct the actin network deformation.
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Affiliation(s)
- Alexandra Colin
- Université Grenoble-Alpes, CEA, CNRS, UMR5168, Interdisciplinary Research Institute of Grenoble, CytoMorpho Lab, Grenoble38054, France
| | - Magali Orhant-Prioux
- Université Grenoble-Alpes, CEA, CNRS, UMR5168, Interdisciplinary Research Institute of Grenoble, CytoMorpho Lab, Grenoble38054, France
| | - Christophe Guérin
- Université Grenoble-Alpes, CEA, CNRS, UMR5168, Interdisciplinary Research Institute of Grenoble, CytoMorpho Lab, Grenoble38054, France
| | - Mariya Savinov
- Courant Institute of Mathematical Sciences, New York University, New York, NY10012
| | - Wenxiang Cao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06520-8114
| | - Benoit Vianay
- University of Paris, INSERM, Commissariat à l'énergie atomique et aux énergies alternatives, UMRS1160, Institut de Recherche Saint Louis, CytoMorpho Lab, Hôpital Saint Louis, Paris75010, France
| | - Ilaria Scarfone
- Université Grenoble-Alpes, CEA, CNRS, UMR5168, Interdisciplinary Research Institute of Grenoble, CytoMorpho Lab, Grenoble38054, France
| | - Aurélien Roux
- Department of Biochemistry, University of Geneva, CH-1211Geneva, Switzerland
| | - Enrique M. De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06520-8114
| | - Alex Mogilner
- Courant Institute of Mathematical Sciences, New York University, New York, NY10012
| | - Manuel Théry
- Université Grenoble-Alpes, CEA, CNRS, UMR5168, Interdisciplinary Research Institute of Grenoble, CytoMorpho Lab, Grenoble38054, France
- University of Paris, INSERM, Commissariat à l'énergie atomique et aux énergies alternatives, UMRS1160, Institut de Recherche Saint Louis, CytoMorpho Lab, Hôpital Saint Louis, Paris75010, France
| | - Laurent Blanchoin
- Université Grenoble-Alpes, CEA, CNRS, UMR5168, Interdisciplinary Research Institute of Grenoble, CytoMorpho Lab, Grenoble38054, France
- University of Paris, INSERM, Commissariat à l'énergie atomique et aux énergies alternatives, UMRS1160, Institut de Recherche Saint Louis, CytoMorpho Lab, Hôpital Saint Louis, Paris75010, France
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38
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Ta HT, Tran NV, Righi MC. Nanotribological Properties of Oxidized Diamond/Silica Interfaces: Insights into the Atomistic Mechanisms of Wear and Friction by Ab Initio Molecular Dynamics Simulations. ACS Appl Nano Mater 2023; 6:16674-16683. [PMID: 37767208 PMCID: PMC10520978 DOI: 10.1021/acsanm.3c02881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 08/21/2023] [Indexed: 09/29/2023]
Abstract
Controlling friction and wear at silica-diamond interfaces is crucial for their relevant applications in tribology such as micro-electromechanical systems and atomic force microscopes. However, the tribological performance on diamond surfaces is highly affected by the working environment where atmospheric gases are present. In this work, we investigate the effects of adsorbed oxygen on the friction and wear of diamond surfaces sliding against silica by massive ab initio molecular dynamics simulations. Different surface orientations, O-coverages, and tribological conditions are considered. The results suggest that diamond surfaces with full oxygen passivation are very effective in preventing surface adhesion, and as a result present extremely low friction and wear. At low oxygen coverage, Si-O-C bond formation was observed as well as atomistic wear initiated from C-C bond breaking at extreme pressure. The analysis of electronic structures of the configurations resulting from key tribochemical reactions clarifies the mechanisms of friction reduction and atomistic wear. Overall, our accurate in silico experiments shed light on the influence of adsorbed oxygen on the tribological properties and wear mechanisms of diamond against silica.
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Affiliation(s)
- Huong
Thi Thuy Ta
- Department of Physics and
Astronomy, University of Bologna, 40127 Bologna, Italy
| | - Nam Van Tran
- Department of Physics and
Astronomy, University of Bologna, 40127 Bologna, Italy
| | - Maria Clelia Righi
- Department of Physics and
Astronomy, University of Bologna, 40127 Bologna, Italy
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39
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Chauhan KV, Rawal S, Patel NP, Subhedar DG. Impact of Deposition Power and Gas Flow Ratio on the Tribological Properties of Titanium Vanadium Nitride Thin Films. Micromachines (Basel) 2023; 14:1788. [PMID: 37763951 PMCID: PMC10534626 DOI: 10.3390/mi14091788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/16/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023]
Abstract
Magnetron sputtering was used for producing titanium vanadium nitride (TiVN) coatings on brass substrates. In this research, we investigate how changing the sputtering power and nitrogen:argon (N2:Ar) gas ratio affects the structural and tribological properties of TiVN coatings. A scanning electron microscope (SEM) was used to examine TiVN coating surface morphology. Both variants showed a gradual increase in the intensity of the TiVN coatings' (111) and (222) peaks. The TiVN coatings' tribological properties were examined using a pin-on-disc tribometer with varying loads, speeds, and sliding distances. The wear rates of TiVN-coated brass pins were in the range of 2.5 × 10-4 to 9.14 × 10-4 mm3/Nm depending on load, sliding distance, and gas ratio variation, when compared to the wear rates of TiVN-coated brass pins deposited at various powers, which ranged from 1.76 × 10-3 to 5.87 × 10-3 mm3/Nm.
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Affiliation(s)
- Kamlesh V Chauhan
- CHAMOS Matrusanstha Department of Mechanical Engineering, Chandubhai S. Patel Institute of Technology (CSPIT), Charotar University of Science and Technology (CHARUSAT), Changa 388421, Gujarat, India
| | - Sushant Rawal
- McMaster Manufacturing Research Institute (MMRI), Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S4L7, Canada
| | - Nicky P Patel
- CHAMOS Matrusanstha Department of Mechanical Engineering, Chandubhai S. Patel Institute of Technology (CSPIT), Charotar University of Science and Technology (CHARUSAT), Changa 388421, Gujarat, India
| | - Dattatraya G Subhedar
- CHAMOS Matrusanstha Department of Mechanical Engineering, Chandubhai S. Patel Institute of Technology (CSPIT), Charotar University of Science and Technology (CHARUSAT), Changa 388421, Gujarat, India
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40
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Samsel MJ, Chańko A, Michałowski M, Fernandez-Munoz M, Diez-Jimenez E. Tribological Characterization of Micro Ball Bearings with and without Solid-State Lubrication. Micromachines (Basel) 2023; 14:1775. [PMID: 37763938 PMCID: PMC10536128 DOI: 10.3390/mi14091775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/17/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023]
Abstract
The tribological characteristics of a below 1 mm micro ball bearing comprising steel disc and cages coated with thin copper and silver films were investigated. Electroplating and laser cutting were used to manufacture used elements. Friction was measured using a linear stage and an adapted version of a friction-loop method. The obtained results show an interesting relationship between the geometric properties of the micro scale thrust bearing and their performance and operational stability, which can be correlated to similar relationships observed in the macro scale. The most optimal design of the bearing showed stable operation, with the simplified rolling resistance coefficient in the range 0.002 to 0.003, independently of applied load, which was in range 150 mN to 1500 mN. The possibility of creating easily manufacturable micro ball bearings with a low rolling resistance coefficient comprised solely of cheap and sturdy elements was shown.
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Affiliation(s)
| | - Artur Chańko
- Faculty of Mechatronics, Warsaw University of Technology, 02-525 Warszawa, Poland
| | - Marcin Michałowski
- Faculty of Mechatronics, Warsaw University of Technology, 02-525 Warszawa, Poland
| | | | - Efren Diez-Jimenez
- Mechanical Engineering Area, Universidad de Alcalá, 28-805 Alcalá de Henares, Spain
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41
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Hernaiz M, Elexpe I, Aranzabe E, Fernández B, Fernández X, Fernández S, Cortada-García M, Aguayo AT. Study of the Effect of ZnO Functionalization on the Performance of a Fully Formulated Engine Oil. Nanomaterials (Basel) 2023; 13:2540. [PMID: 37764569 PMCID: PMC10536302 DOI: 10.3390/nano13182540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023]
Abstract
The automotive sector is demanding higher specifications to achieve maximum efficiency; in this sense a new generation of lubricants with higher thermo-oxidative stability and superior tribological properties is being explored. The formulation of nanolubricants based on the nature of different nanomaterials is one of the most recent approaches, with several gaps to cover, such as dispersion stability, related to the compatibility of proposed nanomaterials with conventional additives and baseoils used in lubricant formulation. This study evaluated the effect of ZnO nanomaterial dispersed in a commercial engine oil using two different approaches; the use of surfactant and nanomaterial surface functionalization to promote higher stability and lower cluster size. Experimental evidence shows a synergetic effect between the tribological protection mechanism and the antioxidant properties in the lubricant. The effect of nanoparticle cluster size, functionalization level, and nanomaterial content are presented.
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Affiliation(s)
- Marta Hernaiz
- Fundación Tekniker, Inaki Goenaga 5, 20600 Eibar, Spain; (I.E.); (B.F.); (X.F.)
| | - Iker Elexpe
- Fundación Tekniker, Inaki Goenaga 5, 20600 Eibar, Spain; (I.E.); (B.F.); (X.F.)
| | - Estíbaliz Aranzabe
- Fundación Tekniker, Inaki Goenaga 5, 20600 Eibar, Spain; (I.E.); (B.F.); (X.F.)
| | - Beatriz Fernández
- Fundación Tekniker, Inaki Goenaga 5, 20600 Eibar, Spain; (I.E.); (B.F.); (X.F.)
| | - Xana Fernández
- Fundación Tekniker, Inaki Goenaga 5, 20600 Eibar, Spain; (I.E.); (B.F.); (X.F.)
| | - Silvia Fernández
- Repsol Technology Lab., Agustín de Betancourt S/N., 28935 Móstoles, Spain; (S.F.); (M.C.-G.)
| | - Martí Cortada-García
- Repsol Technology Lab., Agustín de Betancourt S/N., 28935 Móstoles, Spain; (S.F.); (M.C.-G.)
| | - Andrés T. Aguayo
- Department of Chemical Engineering, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Spain;
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42
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Baxi S, Tripathi AA, Bhatia V, Prasad Dubey M, Kumar P, Bagde H. Self-Ligating Bracket Systems: A Comprehensive Review. Cureus 2023; 15:e44834. [PMID: 37809259 PMCID: PMC10559757 DOI: 10.7759/cureus.44834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/04/2023] [Indexed: 10/10/2023] Open
Abstract
Currently, ligature-free bracket technologies, including self-ligating brackets (SLBs), are all the rage in orthodontics. Self-ligating mechanisms have been shown to be more effective and less time-consuming in orthodontic treatment than traditional appliances due to their enhanced frictional properties. Crucial to the success of the multi-band/bracket method is the transmission of forces and moments from the bracket to the archwire. Advances in bracket design and ligation techniques are constantly being made to better distribute loads and increase the efficiency of leveling.
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Affiliation(s)
- Shalabh Baxi
- Department of Orthodontics, Government Dental College, Raipur, IND
| | - Anand A Tripathi
- Department Of Orthodontics, Saraswati Dhanwantari Dental College and Hospital, Parbhani, IND
| | - Virag Bhatia
- Department of Orthodontics, Government College of Dentistry, Indore, IND
| | - Mangleshwar Prasad Dubey
- Department of Orthodontics, Guru Gobind Singh College of Dental Sciences and Research Centre, Burhanpur, IND
| | - Pratiksha Kumar
- Department of Oral Pathology and Microbiology, Government College of Dentistry, Indore, IND
| | - Hiroj Bagde
- Department of Periodontology, Rama Dental College and Research Centre, Kanpur, IND
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Khatir B, Azimi Dijvejin Z, Serles P, Filleter T, Golovin K. Molecularly Capped Omniphobic Polydimethylsiloxane Brushes with Ultra-Fast Contact Line Dynamics. Small 2023; 19:e2301142. [PMID: 37202658 DOI: 10.1002/smll.202301142] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/18/2023] [Indexed: 05/20/2023]
Abstract
Droplet friction is common and significant in any field where liquids interact with solid surfaces. This study explores the molecular capping of surface-tethered, liquid-like polydimethylsiloxane (PDMS) brushes and its substantial effect on droplet friction and liquid repellency. By exchanging polymer chain terminal silanol groups for methyls using a single-step vapor phase reaction, the contact line relaxation time is decreased by three orders of magnitude-from seconds to milliseconds. This leads to a substantial reduction in the static and kinetic friction of both high- and low-surface tension fluids. Vertical droplet oscillatory imaging confirms the ultra-fast contact line dynamics of capped PDMS brushes, which is corroborated by live contact angle monitoring during fluid flow. This study proposes that truly omniphobic surfaces should not only have very small contact angle hysteresis, but their contact line relaxation time should be significantly shorter than the timescale of their useful application, i.e., a Deborah number less than unity. Capped PDMS brushes that meet these criteria demonstrate complete suppression of the coffee ring effect, excellent anti-fouling behavior, directional droplet transport, increased water harvesting performance, and transparency retention following the evaporation of non-Newtonian fluids.
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Affiliation(s)
- Behrooz Khatir
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, M5S 3G8, Canada
| | - Zahra Azimi Dijvejin
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, M5S 3G8, Canada
- School of Engineering, University of British Columbia, Kelowna, BC, V1V 1V7, Canada
| | - Peter Serles
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, M5S 3G8, Canada
| | - Tobin Filleter
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, M5S 3G8, Canada
| | - Kevin Golovin
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, M5S 3G8, Canada
- Department of Materials Science & Engineering, University of Toronto, Toronto, ON, M5S 3G8, Canada
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Kapshammer A, Laresser D, Miron MC, Baudach F, Major Z. Characterization and Modeling of Ply/Tool and Ply/Ply Slippage Phenomena of Unidirectional Polycarbonate CF Tapes. Polymers (Basel) 2023; 15:3520. [PMID: 37688146 PMCID: PMC10489721 DOI: 10.3390/polym15173520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/14/2023] [Accepted: 08/17/2023] [Indexed: 09/10/2023] Open
Abstract
Thermoplastic tapes are commonly processed by the rapid and efficient stamp forming process. During this forming process, the individual unidirectional tapes of the composite stack move relative to each other and relative to the surface of the tool while being in contact with the corresponding counterpart. As a result, the material exhibits a certain resistance against this movement, which is generally dependent on velocity, normal pressure, and temperature. Therefore, this work investigates the ply/tool and ply/ply slippage of unidirectional, carbon fiber reinforced polycarbonate tapes and provides an alternative implementation of the experimentally observed slippage using cohesive zone modeling. The backbone of the modeling approach is an experimental data set obtained from pull-through experiments. In comparison to common slippage or friction theories, the force plateau of thermoplastic UD tapes at elevated temperatures is observed after an initial force peak has been overcome. For both configurations, ply/tool and ply/ply, a reduction of the initial force peak was observed for increasing temperature. Furthermore, the resulting plateau force value is at least 36% higher in the ply/ply configuration compared to the ply/tool configuration at 200 °C. The derived cohesive zone model allows for accurate modeling of the initial force peak and the plateau.
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Affiliation(s)
- Andreas Kapshammer
- Institute of Polymer Product Engineering, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria;
| | - Daniel Laresser
- Competence Center CHASE GmbH, Hafenstraße 47–51, 4020 Linz, Austria; (D.L.); (M.C.M.)
| | - Matei C. Miron
- Competence Center CHASE GmbH, Hafenstraße 47–51, 4020 Linz, Austria; (D.L.); (M.C.M.)
| | - Felix Baudach
- Covestro Deutschland AG, B207, R428, 51365 Leverkusen, Germany;
| | - Zoltan Major
- Institute of Polymer Product Engineering, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria;
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Trzepieciński T, Najm SM, Ibrahim OM, Kowalik M. Analysis of the Frictional Performance of AW-5251 Aluminium Alloy Sheets Using the Random Forest Machine Learning Algorithm and Multilayer Perceptron. Materials (Basel) 2023; 16:5207. [PMID: 37569911 PMCID: PMC10420024 DOI: 10.3390/ma16155207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 08/13/2023]
Abstract
This paper is devoted to the determination of the coefficient of friction (COF) in the drawbead region in metal forming processes. As the test material, AW-5251 aluminium alloys sheets fabricated under various hardening conditions (AW-5251-O, AW-5251-H14, AW-5251-H16 and AW-5251H22) were used. The sheets were tested using a drawbead simulator with different countersample roughness and different orientations of the specimens in relation to the sheet rolling direction. A drawbead simulator was designed to model the friction conditions when the sheet metal passed through the drawbead in sheet metal forming. The experimental tests were carried out under conditions of dry friction and lubrication of the sheet metal surfaces with three lubricants: machine oil, hydraulic oil, and engine oil. Based on the results of the experimental tests, the value of the COF was determined. The Random Forest (RF) machine learning algorithm and artificial neural networks (ANNs) were used to identify the parameters affecting the COF. The R statistical package software version 4.1.0 was used for running the RF model and neural network. The relative importance of the inputs was analysed using 12 different activation functions in ANNs and nine different loss functions in the RF. Based on the experimental tests, it was concluded that the COF for samples cut along the sheet rolling direction was greater than for samples cut in the transverse direction. However, the COF's most relevant input was oil viscosity (0.59), followed by the average counter sample roughness Ra (0.30) and the yield stress Rp0.2 and strength coefficient K (0.05 and 0.06, respectively). The hard sigmoid activation function had the poorest R2 (0.25) and nRMSE (0.30). The ideal run was found after training and testing the RF model (R2 = 0.90 ± 0.028). Ra values greater than 1.1 and Rp0.2 values between 105 and 190 resulted in a decreased COF. The COF values dropped to 9-35 for viscosity and 105-190 for Rp0.2, with a gap between 110 and 130 when the oil viscosity was added. The COF was low when the oil viscosity was 9-35, and the Ra was 0.95-1.25. The interaction between K and the other inputs, which produces a relatively limited range of reduced COF values, was the least relevant. The COF was reduced by setting the Rp0.2 between 105 and 190, the Ra between 0.95 and 1.25, and the oil viscosity between 9 and 35.
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Affiliation(s)
- Tomasz Trzepieciński
- Department of Manufacturing Processes and Production Engineering, Faculty of Mechanical Engineering and Aeronautics, Rzeszow University of Technology, al. Powst. Warszawy 8, 35-959 Rzeszów, Poland
| | - Sherwan Mohammed Najm
- Kirkuk Technical Institute, Northern Technical University, 36001 Kirkuk, Iraq;
- Department of Manufacturing Science and Engineering, Budapest University of Technology and Economics, Műegyetemrkp 3, H-1111 Budapest, Hungary
| | - Omar Maghawry Ibrahim
- Plant Production Department, Arid Land Cultivation Research Institute, City of Scientific Research and Technological Applications SRTA-City, Borg Al-Arab 21934, Egypt;
| | - Marek Kowalik
- Faculty of Mechanical Engineering, Kazimierz Pulaski University of Technology and Humanities in Radom, 54 Stasieckiego Street, 26-600 Radom, Poland;
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Kostić S, Todorović K, Lazarević Ž, Prekrat D. Friction and Stiffness Dependent Dynamics of Accumulation Landslides with Delayed Failure. Entropy (Basel) 2023; 25:1109. [PMID: 37510056 PMCID: PMC10379126 DOI: 10.3390/e25071109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/12/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023]
Abstract
We propose a new model for landslide dynamics under the assumption of a delay failure mechanism. Delay failure is simulated as a delayed interaction between adjacent blocks, which mimics the relationship between the accumulation and feeder part of the accumulation slope. The conducted research consisted of three phases. Firstly, the real observed movements of the landslide were examined to exclude the existence or the statistically significant presence of background noise. Secondly, we propose a new mechanical model of an accumulation landslide dynamics, with introduced delay failure, and with variable friction law. Results obtained indicate the onset of a transition from an equilibrium state to an oscillatory regime if delayed failure is assumed for different cases of slope stiffness and state of homogeneity/heterogeneity of the slope. At the end, we examine the influence of different frictional properties (along the sliding surface) on the conditions for the onset of instability. Results obtained indicate that the increase of friction parameters leads to stabilization of sliding for homogeneous geological environment. Moreover, increase of certain friction parameters leads to the occurrence of irregular aperiodic behavior, which could be ascribed to the regime of fast irregular sliding along the slope.
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Affiliation(s)
- Srđan Kostić
- Geology Department, Jaroslav Černi Water Institute, Jaroslava Černog 80, 11226 Belgrade, Serbia
- Faculty of Mining, University of Banja Luka, Aleja kozarskog odreda 1, 79101 Prijedor, Bosnia and Herzegovina
- Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, 21102 Novi Sad, Serbia
| | - Kristina Todorović
- Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Žarko Lazarević
- China Road and Bridge Corporation Serbia, Užička 58-A, 11040 Belgrade, Serbia
| | - Dragan Prekrat
- Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
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Nonomura Y, Ogura H, Ueda T, Shibata M, Hiromori K, Shibasaki-Kitakawa N. Mechanical Properties and Friction Dynamics of Organogels Solidified with Rice Paraffin. J Oleo Sci 2023:ess23023. [PMID: 37468272 DOI: 10.5650/jos.ess23023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023] Open
Abstract
Raw materials suitable for a sustainable society have attracted interest in the cosmetics industry. We focused on rice bran as a sustainable material and evaluated the gelation behavior of paraffin extracted from rice bran (rice paraffin) against liquid paraffin, squalane, jojoba oil, and silicone oil. In addition, the frictional properties of the prepared organogel on an artificial skin surface were evaluated using a sinusoidal motion friction evaluation system. Rice paraffin solidified all oils even at the lowest wax concentration of 5 wt%. The hardness and kinetic friction coefficient μk increased with an increase in the wax composition. The hardness and μk of organogels solidified with rice paraffin were smaller than those of gels solidified with petroleum-derived paraffin. These differences are caused by the smaller carbon amount of rice paraffin. The friction parameters depended on the type of oil: the μk of RLG composed of rice and liquid paraffin was greater than that of the other three oils (R, L, and G denote rice paraffin, liquid paraffin, and gel, respectively). These findings promote the development of lipsticks and cleansing gels consisting of sustainable development goal-responsive raw materials.
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Affiliation(s)
- Yoshimune Nonomura
- Department of Applied Chemistry, Chemical Engineering, and Biochemical Engineering, Graduate School of Science and Engineering, Yamagata University
| | - Haruna Ogura
- Department of Applied Chemistry, Chemical Engineering, and Biochemical Engineering, Graduate School of Science and Engineering, Yamagata University
| | - Tatsunari Ueda
- School of Bioscience and Biotechnology, Tokyo University of Technology
| | - Masashi Shibata
- School of Bioscience and Biotechnology, Tokyo University of Technology
| | - Kousuke Hiromori
- Department of Chemical Engineering, Graduate School of Engineering, Tohoku University
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Wierzbicka N, Talar R, Grochalski K, Piasecki A, Graboń W, Węgorzewski M, Reiter A. Influence of Inorganic Additives on the Surface Characteristics, Hardness, Friction and Wear Behavior of Polyethylene Matrix Composites. Materials (Basel) 2023; 16:4960. [PMID: 37512235 PMCID: PMC10381897 DOI: 10.3390/ma16144960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/05/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023]
Abstract
The aim of this research was to analyze the effect of inorganic additives on the tribological properties of the high-density polyethylene (HDPE) matrix composite surface. Titanium (Ti) and hexagonal boron nitride (hBN) were added in different mass fractions. The samples were produced by pressing a pre-prepared mixture of granules. The composite samples with the following mass fractions of additives were fabricated: 5% hBN, 10% hBN, 28% Ti-2% hBN, 23% Ti-7% hBN, and 20% Ti-10% hBN. An even distribution of individual additives' concentrations was confirmed. Observations of morphology, surface topography, hardness, and tribological measurements were conducted using reciprocating motion tests with the "pin-on-flat" and rotational tests with the "pin-on-disc" configuration. Subsequently, microscopic observations and measurements of the wear track profile were carried out. Additionally, geometry parameters of the contacting elastic body were calculated for various counter-samples. It was found that the Shore D hardness of samples containing Ti and hBN increased with the Ti content, while the coefficient of friction (COF) value decreased. The addition of hBN alone did not significantly affect the hardness, regardless of the ratio, while the COF increased with the increasing hBN content. The COF value doubled with the addition of 10% hBN (COF = 0.22), whereas the addition of 90% Ti-10% hBN resulted in a decrease in the COF value, to COF = 0.83. The highest hardness value was obtained for the sample containing 28% Ti-2% hBN (66.5), while the lowest was for the sample containing 10% hBN (63.2). The wear track analysis, including its height and width caused by deformation, was detected using a focal differentiation microscope and scanning electron microscopy. Additionally, EDS maps were generated to determine the wear characteristics of the composite.
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Affiliation(s)
- Natalia Wierzbicka
- Faculty of Mechanical Engineering, Poznan University of Technology, 60-965 Poznan, Poland
| | - Rafał Talar
- Faculty of Mechanical Engineering, Poznan University of Technology, 60-965 Poznan, Poland
| | - Karol Grochalski
- Faculty of Mechanical Engineering, Poznan University of Technology, 60-965 Poznan, Poland
| | - Adam Piasecki
- Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, 60-965 Poznan, Poland
| | - Wiesław Graboń
- Faculty of Computer Science, Rzeszow University of Technology, 35-959 Rzeszow, Poland
| | - Miłosz Węgorzewski
- Faculty of Mechanical Engineering, Poznan University of Technology, 60-965 Poznan, Poland
| | - Adam Reiter
- Faculty of Mechanical Engineering, Poznan University of Technology, 60-965 Poznan, Poland
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Wen B, Li MG, Liu J, Bao JD. Ergodic Measure and Potential Control of Anomalous Diffusion. Entropy (Basel) 2023; 25:1012. [PMID: 37509959 PMCID: PMC10377995 DOI: 10.3390/e25071012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/15/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023]
Abstract
In statistical mechanics, the ergodic hypothesis (i.e., the long-time average is the same as the ensemble average) accompanying anomalous diffusion has become a continuous topic of research, being closely related to irreversibility and increasing entropy. While measurement time is finite for a given process, the time average of an observable quantity might be a random variable, whose distribution width narrows with time, and one wonders how long it takes for the convergence rate to become a constant. This is also the premise of ergodic establishment, because the ensemble average is always equal to the constant. We focus on the time-dependent fluctuation width for the time average of both the velocity and kinetic energy of a force-free particle described by the generalized Langevin equation, where the stationary velocity autocorrelation function is considered. Subsequently, the shortest time scale can be estimated for a system transferring from a stationary state to an effective ergodic state. Moreover, a logarithmic spatial potential is used to modulate the processes associated with free ballistic diffusion and the control of diffusion, as well as the minimal realization of the whole power-law regime. The results presented suggest that non-ergodicity mimics the sparseness of the medium and reveals the unique role of logarithmic potential in modulating diffusion behavior.
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Affiliation(s)
- Bao Wen
- Institutes of Science and Development, Chinese Academy of Sciences, Beijing 100190, China
- School of Public Policy and Management, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ming-Gen Li
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Jian Liu
- Department of Physics, Beijing Technology and Business University, Beijing 100048, China
| | - Jing-Dong Bao
- Department of Physics, Beijing Normal University, Beijing 100875, China
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Evangelista I, Wencel D, Beguin S, Zhang N, Gilchrist MD. Influence of Surface Texturing on the Dry Tribological Properties of Polymers in Medical Devices. Polymers (Basel) 2023; 15:2858. [PMID: 37447503 DOI: 10.3390/polym15132858] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 06/25/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
There is a constant need to improve patient comfort and product performance associated with the use of medical devices. Efforts to optimise the tribological characteristics of medical devices usually involve modifying existing devices without compromising their main design features and functionality. This article constitutes a state-of-the-art review of the influence of dry friction on polymeric components used in medical devices, including those having microscale surface features. Surface tribology and contact interactions are discussed, along with alternative forms of surface texturing. Evident gaps in the literature, and areas warranting future research are highlighted; these include friction involving polymer Vs polymer surfaces, information regarding which topologies and feature spacings provide the best performing textured surfaces, and design guidelines that would assist manufacturers to minimise or maximise friction under non-lubricated conditions.
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Affiliation(s)
- Isabela Evangelista
- School of Mechanical & Materials Engineering, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
- BD (Becton, Dickinson & Company), Blackrock Business Park, Carysfort Avenue, Blackrock, A94 H2X4 Dublin, Ireland
| | - Dorota Wencel
- BD (Becton, Dickinson & Company), Blackrock Business Park, Carysfort Avenue, Blackrock, A94 H2X4 Dublin, Ireland
| | - Steve Beguin
- BD (Becton, Dickinson & Company), Blackrock Business Park, Carysfort Avenue, Blackrock, A94 H2X4 Dublin, Ireland
| | - Nan Zhang
- School of Mechanical & Materials Engineering, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
| | - Michael D Gilchrist
- School of Mechanical & Materials Engineering, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
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