This study evaluates the tribological performance of nanolubricants of a vegetable oil (sunflower oil) reinforced with different concentrations of environmentally-friendly nanoparticles of halloysite clay nanotubes (HNTs). Tribological characterization was performed under different conditions to determine its effect on the nanolubricants’ performance and optimal HNT concentration. The tribological performances under low and high contact pressures were analyzed with a block-on-ring tribometer following the ASTM G-077-05 standard procedure. The extreme pressure (EP) properties of the nanolubricants were determined with a T-02 four-ball tribotester according to the ITeE-PIB Polish method for testing lubricants under scuffing conditions. In addition, the lubrication performance of the newly-developed vegetable oil-based nanolubricants was evaluated in an industrial-type application through a tapping torque test. The results indicated that at a low contact pressure 1.5 wt.% HNTs/sunflower oil provided the best tribological behavior by decreasing the coefficient of friction (COF) and wear volume loss by 29 and 70%, respectively. For high contact pressures, 0.05 wt.% HNTs lowered COF and wear by 55% and 56%, respectively. The load-carrying capacity increased by 141% with 0.10 wt.% HNTs compared to the sunflower oil. A high tapping torque efficiency was obtained with HNTs that can prolong tool life in the machining process. Therefore, this study suggests that HNTs/sunflower oil could be used as green lubricants for industrial applications.
Purpose- Performance appraisal is crucial for enhancing the productivity of employees working in any sector. This paper investigates the prevailing performance appraisal system and promotion policy of selected public commercial banks (Sonali Bank Ltd, Rupali Bank Ltd, and Agrani Bank Ltd) in Bangladesh.
Design/Methodology- The study is a descriptive case of three banks. The researchers interviewed six experienced banking professionals who provided rich data about their respective banks' performance appraisal and feedback systems. The findings of the study are based on the thematic analysis of the respondents’ statements. However, the study also utilized secondary sources for other relevant information.
Findings- The study found that all the banks have an established system for evaluating employee performances through ACR with structured criteria for the promotion. The standard criteria include ACR, academic degree, banking diploma, length of service, etc. However, the grading scale for promoting to different positions is differing among the banks. The study also addressed some limitations of the ACR method as rating only by the manager, biasness on ratings, no appraisal feedback to employees etc.
Practical Implications- The study seeks to drive the attention of policymakers to utilize their existing performance appraisal system better and design a more effective one with a well-established promotion policy to encourage the employees to give their best effort at the workplace.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.