Ultralow Wear Poly(tetrafluoroethylene): A Virtuous Cycle of Wear Reduction and Tribochemical Accumulation

2021 ◽  
Vol 125 (35) ◽  
pp. 19417-19427 ◽  
Author(s):  
K. Istiaque Alam ◽  
D. L. Burris
2021 ◽  
Vol 11 (12) ◽  
pp. 5398
Author(s):  
Tomáš Kot ◽  
Zdenko Bobovský ◽  
Aleš Vysocký ◽  
Václav Krys ◽  
Jakub Šafařík ◽  
...  

We describe a method for robotic cell optimization by changing the placement of the robot manipulator within the cell in applications with a fixed end-point trajectory. The goal is to reduce the overall robot joint wear and to prevent uneven joint wear when one or several joints are stressed more than the other joints. Joint wear is approximated by calculating the integral of the mechanical work of each joint during the whole trajectory, which depends on the joint angular velocity and torque. The method relies on using a dynamic simulation for the evaluation of the torques and velocities in robot joints for individual robot positions. Verification of the method was performed using CoppeliaSim and a laboratory robotic cell with the collaborative robot UR3. The results confirmed that, with proper robot base placement, the overall wear of the joints of a robotic arm could be reduced from 22% to 53% depending on the trajectory.


Author(s):  
Louis De Page ◽  
Pascale Palmers ◽  
Stéphanie Vandenbussche ◽  
Céline Salsac ◽  
Pierre Titeca
Keyword(s):  

2021 ◽  
Vol 13 (13) ◽  
pp. 7331
Author(s):  
Gudrun Erla Jonsdottir ◽  
Throstur Olaf Sigurjonsson ◽  
Ahmad Rahnema Alavi ◽  
Jordan Mitchell

This study aimed to contribute to the strand of literature encompassing governance, sustainability, and stakeholder theory by addressing an inchoate element of responsible ownership: collective action by different stakeholders. Our study’s originality rests on the introduction of an ownership strategy as a governance mechanism for collective action and responsible ownership in order to implement the United Nations Sustainable Development Goals (SDGs) and an environmental, social, and governance (ESG) framework. Using a twofold empirical methodology—studying of archival data and qualitative case work—we provide empirical evidence from a case study of a Nordic energy company showing that applying an ownership strategy helped to strengthen the approach to SDGs and ESG while leading to positive benefits: in this case, the issuance of green bonds. Our theoretical contribution is the addressing of a gap in the literature exploring how an ownership strategy can be a uniting point for collective action, based on the hypothesis that an ownership strategy provides an important reinforcement of a “virtuous cycle”. Policymakers who are interested in promoting long-term commitment of different stakeholders with a focus on sustainability and improved agency should encourage the formulation of an ownership strategy that explains the owners’ commitment to the environment, social causes, and/or governance guidelines. Therein lies the practical contribution of this work. In this study, we found that an ownership strategy with these elements helped to strengthen the firm’s commitment to SDGs and ESG.


2021 ◽  
Vol 69 (2) ◽  
Author(s):  
Jia Ren ◽  
Kuiliang Gong ◽  
Gaiqing Zhao ◽  
Wenjing Lou ◽  
Xinhu Wu ◽  
...  

AbstractThe tribological performances of perfluoroalkylpolyethers (PFPE) with graphene (Gr), WS2, and the mixture of Gr and WS2 (Gr + WS2) before and after ultraviolet (UV), atomic oxygen (AO), and proton (Pr) irradiations were investigated. The composition and structure of PFPE, Gr, WS2, and Gr + WS2 were also analyzed to understand the effects of irradiation on the tribological behaviors of PFPE with additives. The results indicated that serious deterioration and degradation of PFPE took place and Gr was transformed to amorphous carbon after Pr irradiation, and surface oxidation of WS2 occurred under the irradiations of AO and Pr. Moreover, compared to PFPE and PFPE additized with Gr and WS2, PFPE with the addition of Gr + WS2 exhibited excellent friction and wear reduction before and after UV and AO irradiations. Graphical Abstract


Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 732
Author(s):  
Yeoh Jun Jie Jason ◽  
Heoy Geok How ◽  
Yew Heng Teoh ◽  
Farooq Sher ◽  
Hun Guan Chuah ◽  
...  

This study investigated the tribological behaviour of Pongamia oil (PO) and 15W–40 mineral engine oil (MO) with and without the addition of graphene nanoplatelets (GNPs). The friction and wear characteristics were evaluated in four-ball anti-wear tests according to the ASTM D4172 standard. The morphology of worn surfaces and the lubrication mechanism of GNPs were investigated via SEM and EDS. This study also focuses on the tribological effect of GNP concentration at various concentrations. The addition of 0.05 wt % GNPs in PO and MO exhibits the lowest friction and wear with 17.5% and 12.24% friction reduction, respectively, and 11.96% and 5.14% wear reduction, respectively. Through SEM and EDS surface analysis, the surface enhancement on the worn surface by the polishing effect of GNPs was confirmed. The deposition of GNPs on the friction surface and the formation of a protective film prevent the interacting surfaces from rubbing, resulting in friction and wear reduction.


2017 ◽  
Vol 6 (1) ◽  
pp. 61
Author(s):  
Ayumi Yoshikawa ◽  
Shinya Saito ◽  
Makiko Kondo ◽  
Yuko Tsuyumu ◽  
Naruto Taira ◽  
...  

Objective: To clarify how breast cancer patients undergoing post-surgical hormone therapy cope with changes in their sexual lives and support themselves and their partners during these changes.Methods: Participants were 37 breast cancer patients undergoing post-surgical hormone therapy and attending mammary outpatient clinics. In-depth interviews and grounded theory were used to collect and analyze data, respectively.Results: First, sexual life was divided into four groups: “No complaint” regarding sexual activity, “Slight discord”, “Handicapped in meeting a life partner” and “Uninterested” in sexual activity. Sexual life during surgical-hormone therapy did not change significantly from sexual life before breast cancer. Second, meanings of sexual activity for breast cancer patients were divided into five, “Regaining femininity”, “Confirming love”, “Sharing pleasure”, “Response to partner’s higher desire” and “Procreation”. They differed by group. Third, coping strategies were divided into six, “Virtuous cycle to confirm love and regain lost femininity”, “Struggle to avoid relationship crisis”, “Reconfirmation of partner’s affection by his abstinence”, “Attempt to recover the sexual activity they hope for”, “Pursuing children or assuaging partner’s desire by other means” and “Difficulty making a partner continue to have sexual activity”.Conclusions: Nurses should screen breast cancer patients for changes in their sexual lives and to ascertain what sexual activity means to patients, and support them in selecting appropriate coping methods.


2000 ◽  
Vol 66 (644) ◽  
pp. 1341-1348 ◽  
Author(s):  
Hironori MATSUOKA ◽  
Hajime ONO ◽  
Yoshihiro TSUDA ◽  
Kouki GOTO

1999 ◽  
Vol 65 (636) ◽  
pp. 3444-3451
Author(s):  
Hironori MATSUOKA ◽  
Hajime ONO ◽  
Yoshihiro TSUDA ◽  
Kouki GOTO

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