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Gloves
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
Marie-Noëlle Crépy, Pierre Hoerner
Fluorocarbon elastomers (FKM) are advanced materials obtained by copolymerization of various fluoro-monomers such as vinylidene fluoride and hexafluoropropylene. This elastomer family was discovered by DuPont in 1958 and is sold under the trade name Viton™. Nowadays, a few other suppliers offer similar products under different brands. The main interest of FKM is their unique resistance against a wide variety of chemicals, especially most chlorinated and aromatic solvents, and with extreme heat and oil resistance. However, these products remain significantly more expensive compared to any other elastomers.
Experimental investigation of elastomer compatibility and engine performance of biodiesel derived from deodorizer distillate
Published in Biofuels, 2023
Kamalesh A. Sorate, Purnanand V. Bhale
Elastomers such as nitrile butadine rubber (NBR), polyvinyl chloride (PVC), and acrylic rubber showed degrading behavior with palm biodiesel [3]. In another study, NBR showed degrading behavior, while fluorocarbons (FKM1) and (FKM2) showed little property change, i.e. stable behavior with palm biodiesel [4]. In other research, NBR and polychloroprene showed degrading behavior with palm biodiesel [5]. However, polytetrafluoroethylene (PTFE) and silicone rubber (SR) showed stable behavior with biodiesel [6]. Hydrogenated nitrile butadine rubber (HNBR) showed excellent stability with soybean biodiesel [7]. In addition, NBR with high acrylonitrile content (45%) showed stable behavior [8]. FKM showed good resistance and swelling capacity compared to nitrile rubber [9]. The analysis of nitrile rubber hoses with biodiesel showed that an increase in the concentration of biodiesel deteriorates the rubber’s properties [10]. Natural rubber showed a stable nature [11]. Mechanical studies with palm biodiesel under cyclic loading conditions evaluated the Mullins effect on dry and swelled elastomers. Out of two developed models the extended Pseudo-Elastic model was found satisfactory [12]. Viton showed stable behavior with palm biodiesel [13]. The Hansen solubility prediction model, based on biodiesel decomposition, was used. Except for NBR, the predicted parameter and measured values agreed well, although the predicted volume value agreed better with SR, fluorocarbon, ethylene propylene diene monomer (EPDM), and neoprene [14]. A summary of elastomers showing stable and degrading behavior with biodiesel is shown in Table 1.
Combined algorithms for analytical inverse kinematics solving and control of the Q-PRR aerial manipulator*
Published in Mechanics Based Design of Structures and Machines, 2022
Kamel Bouzgou, Laredj Benchikh, Lydie Nouveliere, Zoubir Ahmed-Foitih, Yasmina Bestaoui
The forward kinematic model (FKM) gives the end-effector position that corresponds to a given joint configuration of both the Q-PRR and the robot arm. It is written as follows: where is the operational joint of the end-effector, and is the generalized joints vector of vector of the joint coordinates of the Q-PRR system. The FKM can be decomposed in two sub-FKMs. The first is to determine the generalized end-effector coordinates in the base frame as a function of the joint coordinates of the robot arm. Hence, the FKM of the 3-Dof robot arm based on Denvit–Hartenberg convention is determined by considering the multirotor as the base for the manipulator. Thus, it will be assumed that the first joint is static and fixed to the ground.
Driveline Lubricant Impacts on Dynamic Seal Test Life
Published in Tribology Transactions, 2018
Hongmei Zhao, Jiatong Chai, Xiaoming Lin, Wei Wang, Jeanne Petko, Valerie Woodward, Monica Ford
Compared with the large number of publications on engine oil–seal compatibility, there is a more limited number of publications on driveline lubricant–seal research. Jeon and Kim (1) investigated the impact of low-viscosity oils on engine seal friction and confirmed that using lower viscosity engine oils resulted in reduced frictional loss at the engine seal. Molitor (4) evaluated the performance and failure mode of silicone (VMQ) and fluoroelastomer (FKM) engine crankshaft seals at elevated temperature and recommended FKM over VMQ seals for crankshaft applications. Kurono, et al. (5) investigated the effects of engine oil additives on the properties of FKM seals and found that dithiocarbamate friction modifiers had a hardening effect on FKMs. Masuda, et al. (6) investigated FKM seals collected from field service and found that a loss of interference was the dominant failure mode of FKM seals in real-world service. Shuster (7) developed an accelerated laboratory testing method that mimicked two seal failure modes in field service of off-highway vehicles: (1) abrasive seal lip wear and (2) degradation of the seal due to inefficient lubricity and shaft wear.