Experimental evaluation of physicochemical properties and tapping torque of hexagonal boron nitride in modified jatropha oils-based as sustainable metalworking fluids

In consideration of the important role of environmentally begin metalworking fluid (MWF) in the machining industry, jatropha oil has been acknowledged as a suitable type of lubrication based oil. Despite its advantages, crude jatropha oil (CJO) had its main drawback in terms of poor thermaloxidative stability due to the presence of unsaturated molecules that leads to oxidation reaction. The objective of this study was to evaluate the physicochemical properties and tapping torque of newly developed modified jatropha oils (MJOs). Initially, CJO was chemically modified through the transesterification process at various molar ratios of jatropha methyl ester (JME) to trimethylolpropane (TMP) to produce a series of MJOs denoted as MJO1, MJO3, and MJO5. Hexagonal boron nitride particles at concentrations of 0.05, 0.1 and 0.5 wt% were mixed with the MJOs. MJOs with and without hBN particles were analysed based on the physicochemical testing (i.e., acid value, viscosity, viscosity index (VI) and flash point) and tapping torque test (i.e., tapping torque, thrust force and tapping torque efficiency). Experimental results showed an improvement of physicochemical properties of these newly developed MWFs with the increase in JME:TMP molar ratio and concentration of hBN particles. MJO5 displayed the best physicochemical properties with the highest VI of 196, compared with MJO3 and MJO1. The addition of 0.5 wt% of hBN particles in MJO5 (MJO5c) caused the highest VI achieved at 228, compared with the other samples. The average tapping torque and thrust force were reduced approximately by 15% and 45%, respectively using MJO5a (0.05 wt% of hBN particles with MJO5), compared with SE. MJO5a also demonstrated an improvement of 118% tapping torque efficiency that indicated an excellent machining performance. In conclusion, MJOs containing hBN particles showed better performances on the lubricating property. Among the samples, MJO5a could be proposed to substitute synthetic ester as a sustainable MWF for machining processe

Performance of modified jatropha oil in combination with hexagonal boron nitride particles as a bio-based lubricant for green machining

This study evaluates the machining performance of newly developed modified jatropha oils (MJO1, MJO3 and MJO5), both with and without hexagonal boron nitride (hBN) particles (ranging between 0.05 and 0.5 wt%) during turning of AISI 1045 using minimum quantity lubrication (MQL). The experimental results indicated that, viscosity improved with the increase in MJOs molar ratio and hBN concentration. Excellent tribological behaviours is found to correlated with a better machining performance were achieved by MJO5a with 0.05 wt%. The MJO5a sample showed the lowest values of cutting force, cutting temperature and surface roughness, with a prolonged tool life and less tool wear, qualifying itself to be a potential alternative to the synthetic ester, with regard to the environmental concern

The performance of modified jatropha-based nanofluid during turning process

The industry's extensive use of petroleum-based metalworking fluid (MWF) harms the environment and humans. The production of bio-based MWF, especially from crude jatropha oil (CJO), has therefore taken numerous initiatives. This aimed to formulate newly modified jatropha oil (MJO) with the addition of 0.05wt.% hBN and 0.05wt.% MoS2 as the nanofluid for MWF. The performance of the nanofluids was determined through the turning process in terms of cutting temperature, workpiece surface roughness, tool life and tool wear of the tool lubricated by the nanofluids. The performance of the nanofluid samples was compared with the synthetic ester (SE). From the results, after conducted 100mm axial cutting length MJO+hBN+MoS2 recorded the lowest in cutting temperature and surface roughness compared to all samples. The result shows that MJO+hBN+MoS2 has longer tool life (6500mm) compared to SE (6000mm). Abrasion and adhesion were observed as the dominant tool wear mechanism. In conclusion, MJO+hBN+MoS2 shows better machining performance and has the potential to be an environmentally friendly metalworking fluid

Experimental analysis of tribological performance of modified jatropha oil enriched with nanoparticle additives for machining application

The intensified developments of the vegetable-based metalworking fluids have been growing rapidly due to the environmental and health issue of the utilization of the mineral based oil. The vegetable oils are a great potential substitution of the mineral based oil which has been explored in recent years due to their high biodegradability, renewability and low toxicity in comparable with mineral oil. Non-edible vegetable oil had attracted an attention of the researches in contrast with edible oil which significantly compete with the human food supply. The main focus of this study was to evaluate a new formulation of vegetable-based nanofluid from chemically modified jatropha oil (MJO) blended with hexagonal boron nitride (hBN), graphene and copper oxide (CuO) nanoparticles at 0.05 wt.% concentration. The physicochemical testing was carried out in term of kinematic viscosity, viscosity index and flash point and was compare with commercial synthetic ester (SE). The analysis of MJO mixed with nanoparticles in the perspective of it tribological has been performed through a four ball tribo testing to determine the coefficient of friction, mean wear scar diameter, friction torque, surface roughness and volume wear rate. The results showed that the tribological performance the MJO+0.05wt.% CuO exhibit lowest value in of coefficient of friction and friction torque followed by MJO+0.05wt.% graphene, MJO+0.05wt.% hBN and SE. Nevertheless, the MJO+0.05wt.% graphene and MJO+0.05wt.% hBN provided the significant improvement by providing the lowest value of the mean wear scar diameter and surface roughness respectively. It concluded that the modified jatropha oil enriched with nanoparticles had a great improvement on their tribological performance, hence it’s a highly potential substitution of the SE for machining process

Patient rights in Malaysia - What's new on this bumpy ride?

It is no surprise that generally in a doctor-patient relationship, the dynamics has always been that the doctor retains the upper hand and the patient at the same time willingly allows for this or even that he wants it to be that way. Perhaps this might be explained by the fact that the patient, when presenting himself at the doctor's surgery, is hoping and therefore trusting the doctor's professional judgment so as to be able to identify and diagnose what is ailing him, and then accordingly treat him so that his health is restored. This trust is what underlies the doctor-patient relationship

Developmental research of sustainable technologies to minimise problematic road embankment settlements

Challenging, problematic and non-uniform ground conditions are a night mare to geotechnical engineers tasked with the design and construction of buildings and transport infrastructure. These often suffer undesirable structural settlements. Designing within the current understanding of geotechnics; settlement in peat and organic soils need to be recognised to include the known “primary and secondary consolidation characteristics” and the lesser known “tertiary consolidation phase”. These eventually contribute cumulatively to the consequential uneven and hazardous “bumpy road” surfaces. Undulating flexible road pavements result primarily from the transference of the heavy self-weight of the embankment fill to yielding and non-uniform subgrade. The adoption of conventional design/repair methods such as pile, vertical drain, soil replacement and soil stabilisation are expensive and inappropriate in very soft ground conditions. These then lead to unjustifiably high and repetitive maintenance costs. There being no one quick fix solution for all; pragmatic research must necessarily identify the best/progressively improved practical and sustainable solution. A viable solution is to develop criteria and explore the concept of a “masonry arch bridge structure/lintel-column structure” and adopting sustainable materials through pragmatic searching for appropriate recyclable waste materials. This will lead to the basis for a sustainable, innovative, strong, stiff, permeable composite mat structure that can be used on soft and/or yielding ground conditions. Conceptual lightweight fill technology including the popularly used expanded polystyrene (EPS) and the innovative composite mats recently being developed by the research team are outlined

Decolorization of reactive red-120 by using macrofungus and microfungus

The objectives of the study are to investigate the growth of Aspergillus sp. and Pleurotus sp. and decolorization of Reactive Red – 120 in Minimal Salt Solution (MSS). The growths of fungi were measured every 3 days by using spectrophotometer at 540 nm. For decolorization, the fungi were cultured in 10 mg/L and 20 mg/L of dye concentration. Furthermore, pH of 5, 7 and 9 were used to determine the optimum pH for dye decolorization. The 10 mg/L concentration and pH 5 were chosen as optimum conditions with the maximum performance of reactive dye decolorization ranging of 60%-70%. The Aspergillus sp. was more efficient todecolourize synthetic dye Reactive Red – 120 when compared to Pleurotus sp. This study contributes to the knowledge of mycoremediation and product of mycoremediation kit that could be developed and applied in industry.Keywords: aspergillus sp.; dye decolorization; mycoremediation; pleurotus sp.; reactive red – 120; synthetic dye

Development of combined vector and torque control methods for independent two induction motor drives

Many applications use two or more motors operating in parallel configuration by using one variable speed drive. This system is able to control these multiple motors at the same desired motor speed operation which provide advantages in terms of components and cost reduction. However, the system is not able to control each motor separately if it is desired to operate at different speeds and it also cannot withstand the load disturbance. To address this problem, the design of combined Vector Control-Direct Torque Control (DTC) methods is proposed and their performance is investigated for the case of independent controlled two induction motors fed by single Five Leg Inverter (FLI) method. Double Zero Sequence (DZS) Injection Method Space Vector Pulse Width Modulation (SVPWM) scheme is used for the FLI. Simulation results from the Simulink/Matlab that verify the validity of the method are also included. The results show the ability of the proposed method to control motor speed independently under forward-reverse step speed command and load disturbance condition

Biodegradation of carbamazepine using fungi and bacteria

Carbamazepine is an anti-epileptic pharmaceuticalcompound which is frequently detected in wastewater. However, this compound is hardly degraded naturally due to its persistency. Thus, carbamazepine presents in water stream and household water supply as well as wastewater treatment plant. This paper focuses on various species of fungi and bacteria used in carbamazepine biodegradation and the carbamazepine degrading-enzymes involved in the degradation pathways. Selected research papers on carbamazepine biodegradation using fungi and bacteria were reviewed. The efficiency and approaches in term of methodologies and technologies used were highlighted in this paper. Such study sheds light on gaps of study and future research direction on carbamazepine biodegradation.Keywords: biodegradation; carbamazepine; method; pharmaceuticals