Development of Vegetable Oil-Based Nano-Lubricants Using Montmorillonite Clay (MMT) Nanoparticles as Lubricant Additives

Because of the environmental impact and price volatility, there has been a growing concern on the use of petroleum-based lubricants. This issue has stimulated research into the development of biodegradable lubricants like vegetable oils. In this study, the tribological and rheological behavior of sunflower, peanut, and corn oils modified with Montmorillonite nanoclay (MMT) as lubricant additives were evaluated at various concentrations. A custom-made block on ring tribotester was used to evaluate the wear and friction characteristics of the nano-lubricants, following the ASTM G-077-05 standard. The effects of concentration and shear rate on shear viscosity were studied using a parallel plate rheometer, and the experimental data was compared with conventional models. A custom-made tapping torque tester was used to determine the torque of the specimen following the ASTM D5619-00 standard. Analytical methods, including scanning electron microscopy (SEM), X-Ray diffraction (XRD), thermogravimetric analysis (TGA), and profilometry, were used to characterize the morphology and structure of the MMT nanoclay. The experimental results showed that the volumetric wear, coefficient of friction and torque of the system decreased with the addition of MMT nanoparticles, at different concentrations, compared to the base vegetable oils. In conclusion, the newly developed vegetable oil-based nano-lubricants with the addition of MMT nanoclay, look like a promising environmentally friendly solution to compete with petroleum-based lubricants

Performance Appraisal and Promotion Practices of Public Commercial Banks in Bangladesh- A Case Study on ACR Method

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

Lubrication Performance of Sunflower Oil Reinforced with Halloysite Clay Nanotubes (HNT) as Lubricant Additives

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

Assessment of immune response in cattle against experimentally prepared trivalent (O, A, and Asia-1) FMD vaccine in Bangladesh

This research work was conducted to investigate the effects of age, sex and breed on the induction of immune response against experimentally prepared inactivated trivalent (type O, A, and Asia-1) FMD vaccine. Twenty six cattle were divided into four test groups (Group A, B, C, and D; 5 cattle in each group) and one control group (n=6) based on breed (local and cross), age (≤12 months and >12 months), and sex (male and female). Test cattle were vaccinated with the experimentally prepared trivalent FMD vaccine. Pre- and post vaccinated sera from the vaccinated cattle were collected upto 63 days, and the sera were tested using liquid phase blocking enzyme linked immunosorbent assay (LPBE) that was specific for FMD serotypes O, A, and Asia-1. Antibody titers of all the pre-vaccinated serum samples were found to be under protection level. The females were found to be more protected (90%; n=9/10) as compared to males (70%; n=7/10). The titers obtained were statistically analyzed using t–test to observe the effects of age, breed and sex. It was observed that the mean values of antibody titer in cattle aging >12 months against O, A, and Asia-1 serotypes were significant (P12 months showed better immune response towards trivalent FMD vaccine

Lubrication Performance of Sunflower Oil Reinforced with Halloysite Clay Nanotubes (HNT) as Lubricant Additives

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