Effects of Sintering Temperature on the Density And Porosity of Sodium Chloride Preforms for Open Celled Aluminium Foam Manufacturing

Effects of sintering temperature on the density and porosity of sodium chloride preforms for alu- minium foam manufacturing have been investigated. Cold pressed salt preforms were sintered at 30, 760 and 790 and di erent times ranging between 6- 18 hours in a carbolite furnace at a heating rate of 5/minute. The Results of density and porosity measurements show that the density and porosity of the preform can be varied by changing the sintering temperatures of the preforms. It was observed that the density of the preforms increases with sintering temperature at constant time and pre-sintering pressure while porosity has an inverse relationship with tem- perature. Results of scanning electron microscopic analyses, show sintering connection (bonding) between the salt beads at all the temperatures in which sintering was performed. Sintering of the sodium chloride perform was attributed to grain boundary di usion and evaporation condensation mechanisms.Keywords: sintering, preform, density, porosity, aluminium foa

Swelling Characteristics and Tensile Properties of Natural Fiber Reinforced Plastic in Selected Solvents

The swelling behavior and tensile strength of natural fiber-reinforced plastic in premium motor spirit (PMS), dual purpose kerosene (DPK) and sea water have been studied. Composite formed by reinforcing polyester resin with Okam fibers was immersed in the selected solvents for 16 weeks (4 months). Swelling characteristics of samples of this composite material were determined by monitoring- forth nightly, changes in weight of the samples within the test period and tensile test was conducted on the samples after 16 weeks using Hounsfeild (Monsanto) tensometer. The results show that the solvents reduced the strengths of the composite with PMS giving the highest reduction in strength followed by DPK and then sea water. Reduction in strength was attributed to the weakening of the interfacial bonding between the polyester matrix and reinforcing okam fibers

Effects of Variation of Particle Size and Weight Fraction on the Tensile Strength and Modulus of Periwinkle Shell Reinforced Polyester Composite

The effects of variation of particle size and weight fraction on the tensile strength and Young’s modulus of periwinkle shell reinforced polyester composite have been investigated.  Particulate reinforced polyester composites incorporating varying amounts of periwinkle shell particles (10, 20, 30, 35, 40 and 45wt %) of different particle sizes were characterized for their tensile strength and modulus of elasticity.  The tensile strength and elastic modulus improved with decreasing particle size while they increased with increasing particle loading in the range of particle sizes tested. Increase in strength with small particle sizes and increased particle loading was attributed to increase in surface area which enhanced load transfer between the polyester matrix and periwinkle shell particles

Hybrid Effect on the Mechanical Properties of Sisal Fiber and E-Glass Fiber Reinforced Polyester Composites

The hybrid effect of incorporating periwinkle shell particles into sisal fiber- and E-glass fiber reinforced polyester composite was studied.  Hybrid composites of sisal/periwinkle shell and E-glass/periwinkle shell were prepared at a fixed fiber to polyester ratio of 30:70 and variable ratios of the two reinforcements namely 30:0, 20:10, 15;15, 10:20, 0:30 by weight.  Experimental samples were produced using the hand lay-up method.  Tensile, hardness and flexural tests were performed on these samples and the results showed that the addition of periwinkle shell particles improved the mechanical properties of sisal fiber reinforced composite while it reduced those of E-glass fiber reinforced polyester composite.  Improvement in strength of the sisal/periwinkle hybrid composite was attributed to the ability of the periwinkle shell particles to transfer load to the sisal fibers in the hybrid composite

Alloy Design and Property Evaluation of Ti-Mo-Nb-Sn Alloy for Biomedical Applications

Ti-Mo alloy containing Nb and Sn were arc melted and composition analyzed by EDX. The XRD analysis indicates that the crystal structure and   mechanical properties are sensitive to Sn concentration. A combination of Sn and Nb elements in synergy hindered formation athermal w phase and significantly enhanced b phase stability. The low elastic modulus and good ductility as observed implied that this alloy can be more suitable for biomedical application than the conventional metallic biomaterials from better mechanical compatibility perspective

Effect of Alkali Treatment and Fiber Content Variation on the Tensile Properties of Coir Fiber Reinforced Cashew Nut Shell Liquid (CNSL) Composite

The eect of alkali treatment and ber content variation on the tensile properties of coir ber reinforced cashew nut shell liquid (CNSL) composite was studied. Biocomposite consisting of coir bers and cashew nut shell liquid resin was produced using the hand lay-up technique. The bers were treated with 5% NaOH and varied between 0% to 40% weight fractions. Composite laminates with untreated coir bers were also produced with same ber loadings. The results showed that tensile strength and modulus of the CNSL/COIR composite increased as the weight fraction of coir bers was increased up to a ber content of 30%. Also the composites exhibited reduction in elongation at break as ber content was increased. The alkali- treated CNSL/COIR composite laminates showed improved tensile properties and this was attributed to an improvement of interfacial ber-matrix adhesion in the composites

Inequitable childhood immunization uptake in Nigeria: a multilevel analysis of individual and contextual determinants

Background: Immunization coverage in many parts of Nigeria is far from optimal, and far from equitable. Nigeria accounts for half of the deaths from Measles in Africa, the highest prevalence of circulating wild poliovirus in the world, and the country is among the ten countries in the world with vaccine coverage below 50 percent. Studies focusing on community-level determinants therefore have serious policy implications Methods: Multilevel multivariable regression analysis was used on a nationally-representative sample of women aged 15-49 years from the 2003 Nigeria Demographic and Health Survey. Multilevel regression analysis was performed with children (level 1) nested within mothers (level 2), who were in turn nested within communities (level 3). Results: Results show that the pattern of full immunization clusters within families and communities, and that socio-economic characteristics are important in explaining the differentials in full immunization among the children in the study. At the individual level, ethnicity, mothers' occupation, and mothers' household wealth were characteristics of the mothers associated with full immunization of the children. At the community level, the proportion of mothers that had hospital delivery was a determinant of full immunization status. Conclusion: Significant community-level variation remaining after having controlled for child- and mother-level characteristics is indicative of a need for further research on community-levels factors, which would enable extensive tailoring of community-level interventions aimed at improving full immunization and other child health outcomes

CO2 Uptake on Activated Carbon: A Comparison at Low and High Pressures

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