This paper reports the effects of local cooling media (groundnut oil, palm oil, shea butter and air) on the mechanical properties of heat treated mild steel. Tensile test, hardness test and microstructural analysis were carried out on the heat treated and as-purchased specimens. The results show significant differences in the mechanical properties of the heat treated specimens. The hardness profile showed higher values for palm oil-cooled, shea butter-cooled, and the groundnut oil-cooled specimens in an increasing of order respectively when compared with as-purchased specimen with 194.9 VHN, while a decrease in hardness was recorded for the air-cooled specimen. Furthermore, the yield strength and ultimate tensile strength of the heat treated specimens obtained through the tensile test analysis showed an increase in yield strength for the groundnut oil-cooled (464.4 MPa) and the shea butter-cooled (412.9 MPa) specimens, and a decrease in yield strength for the air-cooled (358.3 MPa) and palm oil-cooled (307.7 MPa) specimens when compared with the as-purchased specimens (376.9 MPa). Also, the same trend was observed in the ultimate tensile strength (UTS) of the specimens. In contrast, the ductility improved in air-cooled specimen (40.28) while decreased in the specimen cooled in the media when compared with as-purchased specimens (34.22). Furthermore, microstructural analysis revealed that the groundnut oil-cooled specimens gave a microstructural quality than the other heat treated specimens.

It is important to monitor the roll bite interface during metal rolling to maintain the product size and homogeneity so as to minimize the material wastage. However, the harsh nature of cold rolling makes installation of sensors in metal roll for industrial applications difficult. The present study used a novel ultrasonic measurement technique whereby an ultrasonic signal went through an external sensor layout arrangement to study the metal-roll interface. The reflection coefficient obtained from the roll-strip interface at 0 o to the roll surface (normal ultrasonic measurement technique) and 19 o (oblique ultrasonic measurement technique) were modelled and experimentally investigated on an instrumented pilot metal rolling mill. Variances of 6.4% and 8.8% were obtained in the reflection coefficient of the techniques from experimental and modelling approaches, respectively. This study showed the ability to use the normal and oblique ultrasonic reflections to study the effect of the angle of incidence wave on the reflection coefficient, and the reflection coefficient obtained from the metal-roll interface is only minimally affected by the incident angle not greater than 19 0 .

This paper reports the influence of solidification rate and stress-relief annealing on the mechanical properties of cast 6063 Aluminium alloy (Al6063). Ingots of Al6063 were melted and then cast using sand and metal moulds. Some of the cast samples were heat treated and then cooled in natural air. Tensile test, hardness test, impact test and microstructural analysis were carried out on the samples. The results show substantial changes in the mechanical properties of the specimens. The ultimate tensile strength, yield strength and hardness percentage elongation of cast Al6063 increases with the use of casting method with high thermal conductivity and reduces when annealing is carried out on the specimens. The ultimate tensile strength of 146.7 MPa and 163.5 MPa were recorded for sand mould and metal mould samples, respectively and the values decreases by 10.3% and 7.5% for the respective moulds. In contrast, the values of impact strength and percentage elongation of cast Al6063 rod improved with the increase in thermal conductivity of casting method and annealing operation. The ductile increased by 51.01% and 45.82% for sand mould and metal mould samples, respectively, after they were annealed. Furthermore, microstructural analysis of cast Al6063 rod revealed a fine-grained structure with increase in thermal conductivity of casting method used; however, the annealing process encouraged grain growth as a result of the stress being relieved from the samples.

Background: Parkinson's disease (PD) is a multifactorial neurodegenerative disease with pathogenic mechanisms traceable to oxidative damage and mitochondrial dysfunction. Rotenone, a chemical compound commonly found in pesticides, has been found to inhibit mitochondrial complex-I and initiate PD-like symptoms in mammals and several invertebrates. Virgin Coconut Oil (VCNO) obtained from the coconut fruit has been found to possess anti-oxidative and anti-inflammatory properties. Objectives: The present study evaluated the effect of VCNO on rotenone-induced Parkinsonism in fruit flies- Drosophila melanogaster (D. melanogaster). Methods: Canton special (CS) strains of D. melanogaster, aged between 1 to 3 days were orally exposed for 7 days to 0, 250, 500 and 750 μM rotenone diet for toxicity assay, and 0, 2.5, 5 and 10 % w/w VCNO diet for longevity assay. Thereafter, 5 % VCNO diet was selected for evaluation against 500 μM rotenone. Subsequently, behavioural test (negative geotaxis), markers for redox status and enzyme activities were evaluated. Results: The results showed that rotenone induced toxicity in the flies, while VCNO increased the lifespan of D. melanogaster in a dose-dependent manner. In addition, VCNO ameliorated rotenone-induced locomotor deficits, elevated MDA, as well as the depleted GSH levels. It also mitigated the inhibited activities of SOD, CAT and ATPase in the flies. Conclusions: VCNO protected D. melanogaster against rotenone-induced toxicity by extending longevity, preventing locomotor deficits and reducing oxidative stress.

Lubrication is essential in metal cold rolling operation to regulate friction at the metal-roll interface, reduce energy loss and improve the product surface finish. A novel non-intrusive pitch-catch technique, based on the reflection of ultrasound, was employed on a pilot mill to evaluate oil-film thickness at the metal-roll interface during the metal cold rolling operation. During the metal rolling process, oil-film thickness was measured under varying rolling load and rolling speed. The oil-film thickness increases as the roll speed increases and reduces as the rolling load increases. The values of oil-film thickness obtained from this non-intrusive ultrasonic technique agree with theoretical values. This study is a proof of concept and has shown promising results. If further developed, the technique could be employed for in situ monitoring of lubricant during rolling operation in metal rolling industries.