Open Access Original Research Article

Thermoelectric Properties of Zn-doped CdO

Alima Mukasia, George S. Manyali, Henry Barasa, James Sifuna

Journal of Materials Science Research and Reviews, Page 1-7

Thermoelectricity is a technology that achieves thermal-to-electric conversion and vice versa. It requires high performance thermoelectric compounds for effective conversion efficiency. The thermoelectric properties of CdO in the rocksalt structure, obtained by first principle calculations are presented. Many thermoelectric materials have low figures of merit hence low conversion efficiency. This research sought to carry out an ab initio study of thermoelectric properties of pristine and Zn-doped cadmium oxide. The properties were obtained by calculating the electronic structure dependent properties. Post processing of the DFT calculation was done using the BoltzTraP and Phono3py codes. From the seebeck coefficient CdO was found to be an n-type semiconductor with a figure of merit (ZT) of 0.30. All the results obtained on pure CdO systems were comparable to the existing literature. Doping was done using the supercell technique. We found 4% doping sufficient to yield a high PF of 10x10-4W/mK2 at 1000K. Hence, Zn doping enhances thermoelectric properties of CdO.

Open Access Original Research Article

Preliminary Studies on the Effect of Size Reduction on Mechanical Properties of Kenaf Particle Reinforced Polymer (K-PRP) Composites for Industrial Application

E. U. Akubueze, C. S. Ezeanyanaso, S. O. Muniru, F. C. Nwaeche, C. O. Nwankwo, C. C. Igwe, G. N. Elemo

Journal of Materials Science Research and Reviews, Page 1-5

Aims: The present study aims to investigate the effect of size reduction on mechanical properties of kenaf particle reinforced polymer (K-PRP) composites for industrial application.

Study Design: Decorticated kenaf mixed (core & bast) fibres were sourced from Institute of Agricultural Research and Training (IAR&T), Ibadan. Decorticated core and bast kenaf fibres were separated and chopped into pieces followed by fibre modification and composite fabrication.

Results and Discussion: The results showed that the optimum fibre loading and particle size for achieving the highest tensile strength of reinforced composite was 30% and 80 µm respectively. The elongation break of the composite decreased as the fibre loading is increased. It is revealed that the fabricated composite sheets applying optimum fibre loading and particle size were stable to an aggressive hygrothermal environment. Prototype packaging material was fabricated and this project gears towards attaining Nanoparticles (K-NPs) for strength enhancement and structural flexibility.

Conclusion: The properties of composites depend on interfacial compatibility and adhesion between hydrophilic fibre and hydrophobic matrix.  The unmodified fibre used in composite fabrication showed high moisture absorption, poor wettability, and environmental instability.

Open Access Original Research Article

Boundary Integral Equation Modeling of 2D Functionally Graded Anisotropic Structures

Saleh M. Al-Harbi, Alanod M. Sibih

Journal of Materials Science Research and Reviews, Page 1-8

Aims: The main purpose of this paper is to present a boundary integral equation modeling to obtain the solution for the problems of magneto-thermoelastic functionally graded anisotropic (FGA) structures in the context of the Green and Naghdi theory of type III.

Study Design: Practical shape optimisation technique.

Place and Duration of Study: Jamoum laboratory, June 2017.

Methodology: A new practical shape optimisation technique based on a predictor-corrector implicit-implicit staggered algorithm, which was implemented for use with the time-stepping dual reciprocity boundary element method (DRBEM) to obtain the final coupled linear system of equations for temperature and displacements that describe the magneto-thermoelastic structural analysis problem of functionally graded anisotropic (FGA) structures in the context of the Green and Naghdi theory of type III.

Results: A numerical results demonstrate validity, accuracy, and efficiency of the presented technique.

Conclusion: Our results thus confirm that our technique is efficient and precise. It is noted that the obtained DRBEM results are more accurate than the FEM results, the DRBEM is more efficient and easy to use than FEM because it only needs the boundary of the domain needs to be discretised. The results of DRBEM at any point are more precise, because DRBEM's integration operation is smoother than FEM's differentiation operation. Also from this knowledge of the variation of the displacements and temperature sensitivities with time for multilayered FGA structures, we can design various structures to meet specific engineering requirements and utilise within which to place new information can be more effective.

Open Access Original Research Article

Adsorption Energies of Lithium and Sodium Ions on Vanadium Disulphide: A DFT Study

Gloria I. Murila, George S. Manyali, Henry B. Wafula

Journal of Materials Science Research and Reviews, Page 1-6

Various energy sources are utilized at present with a challenge of energy storage in many cases. The existing rechargeable storage batteries which include sodium-ion and lithium-ion batteries have some limitations in their gravimetric capacities. Ab initio methods based on density functional theory (DFT) was used to investigate the adsorption of lithium ions and sodium ions on layered Vanadium disulphide. Metallic VS2 monolayer has a higher theoretical gravimetric capacity of 466mAh/g. This study showed that Sodium adsorbs on monolayer VS2 with lower adsorption energy of -2.00eV compared to Lithium (1.47eV) and it is more stable.

Open Access Review Article

Mechanism of Action of Antibacterial Activity of Biosynthesised Zinc Oxide Nanoparticles - A Review

N. Tensingh Baliah

Journal of Materials Science Research and Reviews, Page 1-8

Now-a-days, nanotechnology has become increasingly important in the biomedical and pharmaceutical antimicrobial strategy due to their wide spectrum of action at nano-scale level. Antibacterial agents are very important in the textile industry, water disinfection, medicine, food packaging etc. This review focuses on the synthesis and mechanism of antibacterial activity of zinc oxide nanoparticles (ZnO NPs). The antibacterial activity of ZnO NPs is determined by the mode of synthesis, organisms used, size of the nanoparticles etc. The variations in the antibacterial activity of ZnO NPs are mostly attributed to their high specific surface area-to-volume ratios and their distinctive physicochemical properties.