The corrosion behaviors of mild steel in NaCl aqueous solution with different Zn2+ concentrations have been investigated electrochemically. The immersion potentials were influenced by the presence of Zn2+ and shifted to the positive direction with increasing the Zn2+ concentration in the solutions. Zn2+ suppressed the current density in both cathodic and anodic polarization, and the inhibition effects increased with increasing the Zn2+ concentrations. The electrochemical impedance spectroscopy (EIS) results showed the highest charge transfer resistance in the Zn-rich solution due to the formation of Zn-layer with the steel surface. The Zn-layer thickness increased, and the area of defects in the oxide film on the steel surface decreased with increasing the Zn2+ concentration. Therefore, it was suggested that the corrosion inhibition ability of mild steel in NaCl aqueous solution significantly improved with increasing the concentration of Zn2+ in the solution.
The effect of incorporating granite powder and fibres (oil palm and polyethylene plastic) into soil for sun dried brick production was investigated. Initial tests were conducted on the soil and the granite powder so as to obtain all the relevant index properties of the materials to be used. Fifteen percent granite powder, by weight of the soil was added to the soil as a binder and palm and plastic fibres as enhancer for sun dried bricks production. The bricks were tested for their compressive strength and validated with Finite Element Numerical Model. It was observed that at 1.0% fibre addition, the compressive strength increased, by 17% and 29.7% for the palm and plastic fibre respectively. At 1.5%, fibre content the corresponding values were even higher at 28.6% and 38.3% increase over the control brick without fibres. The granite powder soil brick with the highest weight fraction of fibre were found to provide the best correlation between the Finite Element Analysis (FEA) model and the experimental observation in relation to both the loading path and maximum strength. The FEA predicted the real behaviour well, and the composite action between the fibres and the soil could be seen largely as an enhancement through a tensile strength provided by the fibres to contain and retain the soil in place to continue to carry the compressive force. Further work is recommended to continue with the validated numerical model tool to design a fibre - enhanced granite powder soil brick with required performance characteristic for practical use in construction.
This work is on modeling injection moulding parameters for a bio-fibre filled polymer composite in this case its flexural response. Mercerization and acetylation treatments were applied in surface modification of the bio-fibre. These fibres were ground and sieved into three particle sizes and applied as fillers in the matrix (high density polyethylene). The composites were compounded applying Taguchi robust design of experiment considering seven injection moulding parameters and one non-machine parameter being volume fraction of the reinforcing fibre. An L18 orthogonal array at mixed levels was adopted for the experiment and response evaluation. Analysis on the composites of the three particle sizes show that volume fraction was control factor that has the highest influence on the flexural properties of the composites. Analysis of variance (ANOVA) showed that the independent variables in the models can explain over 80% of the response, hence indicating response model fit. The generated predictive models indicated a goodness of fit, hence can comfortably predict the response.
Recovery of metals serves as an attractive approach to gain precious and rarely available metals on earth which are important in industries. For years many methods have been practiced for this recovery such as adsorption, liquid-liquid extraction, or membrane processes. Adsorption provides a beneficial offer compared to others due to its cheap, easy maintenance, and high efficiency. Lately, the focus of adsorption has shifted to the use of bio-sorbent derived from a natural resource, including chitin and chitosan. Chitin and chitosan, which mainly produced from crab and shrimp shell, have been explored for any kind of precious metal recoveries such as platinum, palladium, gold, silver, and others. Various modifications to its structure also have been employed in order to gain more efficient performance. Here we are going to discuss chitin and chitosan along with their engineered and modified form recent advances on precious metal recovery as well as their potential of future research opportunities.
We review work on rechargeable metal-ion batteries. Rechargeable metal-ion batteries play a crucial role in modern transport, communication and electronic industries with lithium ion batteries being the most common on the market. Despite the successful application, of lithium-ion batteries; their energy density, volumetric and gravimetric capacities, life span and charge /discharge rate have raised a lot of concern. Current research is being focused on the anode materials currently in use and also substituting Lithium/Sodium ion batteries. This review, we look into the structural, electronic and electrochemical properties of a newly synthesized Vanadium disulphide as promising near future anode for both sodium and lithium ion batteries
