Selection of Natural Fiber for Hybrid Kevlar/Natural Fiber Reinforced Polymer Composites for Personal Body Armor by Using Analytical Hierarchy Process

Kevlar 29 is the most widely used synthetic fiber for body armor applications and they have been derived from petroleum based resources. Depletion of petroleum resources and the increase in awareness about the eco-friendly materials encouraged the researchers to explore the potential use of natural fiber as an alternative for synthetic fibers. Hybridization of natural fiber with synthetic fiber will result in unique properties which is difficult to obtain from the individual fibers. In this research Analytical Hierarchy Process (AHP) was used to identify the most suitable natural fiber to be hybridized with Kevlar 29 fiber as a reinforcement in the polymer composites for personal body armor. Fourteen natural fibers and seven criteria's were selected and analyzed for hybridization with respect to the personal body armors design specification. Cocos nucifera sheath which is a naturally woven fiber yields the highest priority vector and it was selected as a most promising natural fiber for hybridization with Kevlar 29 for personal body armor. Eventually, sensitivity analysis was carried out to check the stability of the priority ranking

Tetanus and Diphtheria Seroprotection among Children Younger Than 15 Years in Nigeria, 2018: Who Are the Unprotected Children?

Serological surveys provide an objective biological measure of population immunity, and tetanus serological surveys can also assess vaccination coverage. We undertook a national assessment of immunity to tetanus and diphtheria among Nigerian children aged <15 years using stored specimens collected during the 2018 Nigeria HIV/AIDS Indicator and Impact Survey, a national cross-sectional household-based survey. We used a validated multiplex bead assay to test for tetanus and diphtheria toxoid-antibodies. In total, 31,456 specimens were tested. Overall, 70.9% and 84.3% of children aged <15 years had at least minimal seroprotection (≥0.01 IU/mL) against tetanus and diphtheria, respectively. Seroprotection was lowest in the north west and north east zones. Factors associated with increased tetanus seroprotection included living in the southern geopolitical zones, urban residence, and higher wealth quintiles (p < 0.001). Full seroprotection (≥0.1 IU/mL) was the same for tetanus (42.2%) and diphtheria (41.7%), while long-term seroprotection (≥1 IU/mL) was 15.1% for tetanus and 6.0% for diphtheria. Full- and long-term seroprotection were higher in boys compared to girls (p < 0.001). Achieving high infant vaccination coverage by targeting specific geographic areas and socio-economic groups and introducing tetanus and diphtheria booster doses in childhood and adolescence are needed to achieve lifelong protection against tetanus and diphtheria and prevent maternal and neonatal tetanus

Effect of curing temperature on mechanical properties of bio-phenolic/epoxy polymer blends

Nowadays, researchers continue studies for alternative materials to replace the redundant petroleum-based products. The combination of various polymer mixture process mainly from bio-polymer material as a matrix property could reduce the dependence over petroleum-based polymer, thus the dangerous residue waste from the synthetic polymer in the fabrication process could be eliminated and produce better composite material with lower cost and high performance of composite material in numerous applications. In this study, the effect of bio-phenolic loading and curing temperature on the mechanical properties of bio-phenolic/epoxy polymer blends was investigated. Bio-phenolic/epoxy polymer blends were fabricated with different loading of bio-phenolic resin (5(P-5), 10(P-10), 15(P-15), 20(P-20) and 25(P-25) wt%) and different curing temperature was used which is 100 °C, 130 °C and 150 °C. The overall mechanical properties of bio-phenolic/epoxy polymer blends were improved as bio-phenolic loading increase and curing temperature increase. Obtained results indicated that bio-phenolic/epoxy polymer blends with 20 wt% bio-phenolic at 150 °C showed the highest tensile strength, flexural strength and impact resistance whereas highest tensile modulus and flexural modulus was shown by polymer blend with 25 wt% bio-phenolic at 100 °C and 25wt% bio-phenolic at 130 °C, respectively. It can be concluded that polymer blend with 20wt% bio-phenolic at 150 °C showed overall good mechanical properties. On the basis of finding obtained in this work will be used for further study to fabricate flax fiber/carbon-kevlar reinforced in optimum polymer blends for ballistic helmet applications