Ballistic Performance of a Quenched and Tempered Steel Against 7.62mm Calibre Projectile

In this research effort, ballistic performance of a quenched and tempered steel was investigated. Low alloy steel was selected where austenization, quenching and finally tempering at 600oC were applied to it. Thereafter, the heat-treated steel was shot with armour piercing 7.62 mm calibre and the occurrence of failure, after the interaction between the projectile and the steel, was investigated. The shot was performed at zero degree (0º) obliquity with a projectile velocity of 830m/s. After the shot, microstructural and fractographical examinations were carried out on the sample taken from the perforated region using scanning electron microscopes to determine the matrix phase and secondary phases. It was observed that the steels had tempered martensitic-bainitic matrices after heat treatments; a crater was formed on the front side of the steel; deformed and transformed adiabatic shear bands had an effect on the crack formation and propagation in the matrix; and perforation mode of the steels was typical petalling.http://dx.doi.org/10.4314/njt.v34i2.1

Nutritive value, growth performance and haematological parameters of West African dwarf sheep fed preserved pineapple fruit waste and cassava by- products

Twelve West African dwarf sheep, aged between 6 to 8 months and weighing 9 to 10.5 kg were randomly allocated to four treatments consisting of ensiled pineapple fruit waste and cassava root meal (CRM+PFW); sun-dried pineapple fruit waste (PFW); ensiled cassava peels and pineapple fruit waste (CP+PFW); cassava peel and cassava root meal (CP+CRM), to determine the performance, digestibility and haematological parameters in a completely randomised design in a 56 day feeding trial. The results revealed that there were differences (p<0.05) in the daily weight gain of the animals. Animals fed CP+PFW had significantly (p<0.05) higher daily weight gain than other treatments. Daily DM intake also followed the same trend. Daily weight gain observed for CRM+PFW, PFW, CP+PFW, CP+CRM were 23.57g/day, 59.28g/day, 66.43g/day and 40.71g/day, respectively. Sun-dried pineapple fruit waste diet induced (p<0.05) the highest water intake of 1.93litre/day. All the haematological and serum biochemical indices were influenced (p<0.05) by the treatments. Packed cell volume (PCV) ranged from 28% to 37%, while haemoglobin concentration (Hb) ranged from 9.5g/dl to 12.5g/dl. Albumin and total protein values ranged significantly (P<0.05) from 32.7 to 37.8g/dl and 41.7 to 78.2 g/l respectively. It was concluded that animals on CP+PFW had the best growth performance, hence, ensiled pineapple fruit waste +cassava peels can be recommended to sheep farmers for better intake and performance especially during the austere periods.Keywords: Sheep, Pineapple waste, ensiling, cassava pee

Effects of dispersion and particle-matrix interactions on mechanical and thermal properties of hnt/epoxy nanocomposite materials

Halloysite nanotubes (HNTs), naturally occurring as aluminosilicate nanoclay mineral, have recently emerged as a possible nanomaterial for countless applications due to their specific chemical structure, tubular shape, high aspect ratio, biocompatibility and low toxicity. In this study, HNTs were incorporated into the epoxy resin matrix to improve its mechanical properties and thermal stability. However, heterogeneous size, surface charge and surface hydrogen bond formation, result in aggregation of HNTs in epoxies to a certain extent. Three specific techniques were used to integrate HNTs into neat epoxy resin (NE). The structure and morphology of the embedded nanotubes were confirmed by Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Tensile testing was carried out and the fractured surface of the tested specimen was analysed using scanning electron microscopy (SEM). The thermal stability of the prepared nanocomposite materials was investigated by thermogravimetric (TG) and derivative thermogravimetry (DTG) studies. The obtained results indicated that improved properties of HNTs/epoxy nanocomposite materials were related to the unique properties of well-dispersed HNTs, agglomerate scale, and reduced void presence, and could be controlled by the manufacturing processes