Engineering Commons^™

Adhesion And Deformation Mechanisms Of Polydopamine And Polytetrafluoroethylene: A Multiscale Computational Study, Matthew Brownell

Graduate Theses and Dissertations

Polydopamine (PDA) has been shown to bond via covalent bonding, van der Waals forces, and hydrogen bonding and is known to adhere strongly to almost any material. The application of PDA between a substrate and a PTFE surface coating has resulted in low friction and a greatly reduced wear rate. Previous research probing the capabilities and limitations of PDA/PTFE films have studied the wear and mechanical properties of the film, but the overall adhesive and deformation mechanisms remain unclear.

In this research, we investigate the tribological properties of PDA and PTFE molecules and composites from the atomic to the microscale …

Rubber Plunger Surface Texturing For Friction Reduction In Medical Syringes, Haytam Kasem, Harel Shriki, Lihi Ganon, Michael Mizrahi, Kareem Abd-Rbo, Abraham J. Domb

Friction

Friction is a genuine issue in the use of many medical devices involving rubbery materials such as plungers in medical syringes. This paper presents a new direction for the reduction of friction in medical syringes based on surface texturing of the rubber plunger. The specimens were prepared by casting poly(vinylsiloxane) (PVS) rubber into a pre-fabricated negative template obtained by 3D printing. Friction tests were performed on a home-made test-rig. It was clearly shown that friction resistance can be considerably manipulated when using textured plungers.

Friction And Wear Behaviors Of Mos2-Multi-Walled-Carbon-Nanotube Hybrid Reinforced Polyurethane Composite Coating, Zhaozhu Zhang, Mingming Yang, Junya Yuan, Fang Guo, Xuehu Men

Friction

MoS2-multi-walled-carbon-nanotube (MWCNT) hybrids containing two-dimensional MoS2 and one-dimensional MWCNTs were synthesized through a one-step hydrothermal reaction. X-ray-diffraction and transmission-electron-microscopy results demonstrated that MoS2 nanosheets were successfully synthesized, and uniformly anchored on the MWCNTs' surfaces. Furthermore, the effects of the MoS2-MWCNT hybrids on the tribological performances of polyurethane composite coatings were investigated using a UMT-2MT tribo-tester. Friction and wear test results revealed that the friction coefficient and wear rate of a 3 wt% MoS2-MWCNT-1 filled polyurethane composite coating were reduced by 25.6% and 65.5%, respectively. The outstanding tribological performance of the MoS2-MWCNT-1 reinforced polyurethane composite coating was attributed to the excellent …

Friction Predication On Pin-To-Plate Interface Of Ptfe Material And Steel, Zhuming Bi, Donald W. Mueller

Friction

In this paper, the friction behavior at a pin-to-plate interface is investigated. The pin and plate are made of Polytetrafluoroethylene (PTFE) and steel, respectively, and there is a reciprocating motion at the interface. Governing mathematical models for the relations of design variables and frictions are investigated, and a general procedure is proposed to solve the developed models and predict the friction forces at the interface subjected to given test conditions. Novel models have been developed to represent intrigued friction behaviors affected by various factors such as pin geometrics and finishes, lubrication conditions, and reciprocating speed. The test data from experiments …

Water-Based Superlubricity In Vacuum, Chen Xiao, Jinjin Li, Lei Chen, Chenhui Zhang, Ningning Zhou, Tao Qing, Linmao Qian, Jiyang Zhang, Jianbin Luo

Friction

This study achieved water-based superlubricity with the lubrication of H3PO4 solution in vacuum (highest vacuum degree <10-4 torr) for the first time by performing a pre-running process in air before running in vacuum. The stable water-based superlubricity was sustainable in vacuum (0.02 torr) for 14 h until the test was stopped by the user for non-experimental factor. A further analysis suggested that the superlubricity may be attributed to the phosphoric acid-water network formed in air, which can efficiently lock water molecules in the liquid lubricating film even in vacuum owing to the strong hydrogen bond interaction. Such capability to lock water is strongly affected by the strength of hydrogen bond and environmental conditions. The realization of water-based superlubricity with H3PO4 solution in vacuum can lead to its application in space environment.

Recovery Of Worn Parts By Electrodes, Sh.Kh. Yuldashev, M.N. Masharipov

Journal of Tashkent Institute of Railway Engineers

Studies have been worked on the restoration of various perishable parts with welding. The main purpose of the research is to increase the strength of the working surfaces of parts different coating by welding different types of covered electrodes. Studies have been carried out to determine the composition, structure, rigidity and eroding resistance of the welded covering material. As a result of laboratory research, the optimal composition of the covering material is determined and the optimal method of welding them to the eroded working surface of the parts is selected.

Calculation Of Seismic Resistance Of Reinforced Concrete Railway Spans Without Prestressing Reinforcement, U.Sh. Raxmanov, G.B. Ismailova

Journal of Tashkent Institute of Railway Engineers

The article discusses the calculation of earthquake resistance of reinforced concrete rail spans without prestressing reinforcement. The calculation is made for the main and special combination of loads. The calculation results show that with a design seismicity of 8 points, the bending moment in the middle of the beam span will significantly decrease compared to a design seismicity of 9 points

Hybrid Nanocellulose-Copper (Ii) Oxide As Engine Oil Additives For Tribological Behavior Improvement, Sakinah Hisham, Kumaran Kadirgama, Hussein A. Mohammed, Amit Kumar, Devarajan Ramasamy, Mahendran Samykano, Saidur Rahman

Research outputs 2014 to 2021

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Friction and wear are the main factors in the failure of the piston in automobile engines. The objective of this work was to improve the tribological behaviour and lubricant properties using hybrid Cellulose Nanocrystal (CNC) and Copper (II) oxide nanoparticles blended with SAE 40 as a base fluid. The two-step method was used in the hybrid nanofluid preparation. Three different concentrations were prepared in a range of 0.1% to …

Increasing The Strength Of Worn Parts Withcomposite Materials, Masud Numonzhonovich Masharipov, Shuhratbek Xabibullo Ogli Yuldashev

Journal of Tashkent Institute of Railway Engineers

Researches are carried out on the built-up curly details. The aim of the study is to restore worn surfaces of parts by surfacing of powder composite materials. Inves-tigations are carried out to determine the composition, structure, hardness and wear resistance of the deposited layers. As a result of laboratory studies, the opti-mal composition of the surfacing material and the rational method of applying them to the worn surfaces of machine parts are selected.

Solutions Of The Problem Of Random Vibrations In Hereditary-Deformable Systems Using Impulsive Functions, Inobat Xaldibayeva

Technical science and innovation

In recent years, probabilistic-statistical methods for studying various problems of mechanics of solid deformable bodies are being applied more than ever.

The principal part of its field of application is the development of a general theory of strength and a hereditarily deformed solid. As known, the theory of random oscillations is increasingly being used in technology.

Current research is aimed to present a numerical-analytical approach for studying the dynamic response of a hereditarily deformable system to unsteady input influences.

It is established that the dynamic reaction of hereditarily deformable systems to an arbitrary form of random perturbations can also be …

Procedure For Asphalt Mixture Friction Evaluation For Wvdoh, Danielle Marie Hoyer

Graduate Theses, Dissertations, and Problem Reports

Monitoring asphalt skid resistance in the laboratory could aid in improved friction prediction capabilities and provide insight for developing alternative asphalt mixture designs in the future. The West Virginia Department of Highways (WVDOH) sought the design of a laboratory accelerated asphalt polishing machine to further expand on current skid resistance measurement practices. The design is modeled after the North Carolina State University (NCSU) polishing machine detailed in ASTM E660. The purpose of this research was to develop a testing procedure for the polishing equipment. Friction was monitored with the British Pendulum Tester (BPT) according to ASTM E303.

Specimens were prepared …