Development and characterization of light weight laminated composite under impact loading

"December 2013.""A Thesis presented to the Faculty of the Graduate School University of Missouri--Columbia In Partial Fulfillment of the Requirements for the Degree Master of Science."Thesis supervisor: Dr. Sanjeev K. Khanna.Today, armor protection is one of the most important elements of survivability. So developing materials which can withstand all futuristic threats, including those from terrorism has therefore become very critical. Polymer matrix composites (PMCs) are attractive materials in this regard because they are lighter, stronger, and stiffer than unreinforced polymers. Along with PMCs, steel and aluminum alloys are also used in light weight armor materials against projectile impact. The laminated composite materials in which different layers of different materials are bonded together are becoming a key material for future lightweight military, marine, and aerospace hardware as they incorporate high hardness and sufficiently high toughness simultaneously. In this study a layered composite panel of steel and aluminum layers has been bonded with graphene reinforced polyurethane. Four types of laminated panels were fabricated with steel facing plate followed by a combination of various aluminum alloy layers. The average weight of a 7-layer laminated composite was 7 lb/ft² and that of 9-layer laminated composites was 10 lb/ft². Different tests, such as tensile test, lap shear strength test, and three-point bend test, have been conducted on the fabricated panels to determine their mechanical properties. The composite laminates' bending stiffness was modeled using ABAQUS finite element software and validated by experiments. The effect of a ballistic impact with armor piercing ammunition was also conducted to qualitatively measure their relative resistance to failure under ballistic loading.Includes bibliographical references (pages 74-77)

Effect of Different Supplementary Cementitious Material on the Microstructure and its Resistance Against Chloride Penetration of Concrete

Various research programes on long term durability of concrete are going on through -out the world. An attempt is made to study the microstructure of the concrete with the addition of different SCM like fly ash, GGBS, metakaolin, silica fume, and rice husk ash. In this paper, data is presented in a simplified manner for the sake of convenience. Hydration is a continuous process and so microstructure of HPC and interfacial zone (ITZ) can change with age and effect of environment by the influencing agents present in it. Rapid chloride permeability test (RCPT) is carried out on the various samples prepared with fly ash, GGBS, metakaolin, silica fume, and rice husk, are presented in this paper

Obstetric and perinatal outcomes of expectant management and immediate induction of labour in term premature rupture of membranes: promising outcomes from expectant management cohort

Background: Premature rupture of membranes (PROM) is common obstetric entity, the management even at term is controversial and there is no consensus for definite protocol of management. Objective of the present study is to compare the effectiveness, safety of expectant management of 24 hours and immediate induction with PGE2 gel in terms of maternal and fetal outcome in term PROM.Methods: 200 women were randomized to group A expectant management and group B immediate induction, after strict Inclusion and exclusion criteria. In expectant group waiting period was 24 hours. Multiple end points were examined throughout management. Chi square test and independent t tests were performed for statistical analysis. P value<0.05 was considered significant.Results: Demographic parameters of patients, maternal and gestational age were similar in both groups. Primigravidae were more in both groups A and B. Vaginal delivery rate is more in expectant group and Caesarean Section rate is high in immediate induction group. CS rate was 37% and 23% in group A and B respectively; the difference is statistically significant (p value=0.031). ‘ROM to delivery interval’ was more in group A (16.31±8.67 hrs and 13.85±5.46 hrs) (p value=0.0256). Hospital stay was comparatively more in group A (5.40±0.81 days and 4.11±0.86 days) (p value=0.435). Infective morbidity of mother and baby was low in both groups and no difference was seen.Conclusions: An expectant management allows a good number of women to go into labour and deliver vaginally without an increase in CS rate and infectious morbidity for mother and fetus

Successful deliveries in a case of spontaneous pregnancy in ‘uterus bicornis unicollis’ with dicavitory twin gestation: a rare case report

Congenital anomalies of the uterus cervix and vagina are caused by alterations in development or fusion of the Mullerian ducts and are associated with multiple obstetric problems. A 32-year-old primigravida presented with spontaneous conception of dichorionic diamniotic twin with one twin in the right horn and another in the left horn of a bicornuate uterus. At 31.4 weeks of gestation the patient presented with preterm premature rupture of membranes followed by preterm labour, and progressed to deliver vaginally, resulting in the successful delivery of a live twin male and female baby. Spontaneous twin pregnancies in case of uterus bicornis unicollis are reported rarely. Here we discuss an extremely rare occurrence of spontaneous dicavitatory twin pregnancy in uterus bicornis unicollis and its outcome

Instrumentation of KGF nucleon decay experiment

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