Concrete is among the most common materials utilized to construct protective elements in hardened structures. Subsequently, understanding how a concrete member will respond to explosively driven fragment or projectile impact is critical to the protective design process. Explosively driven fragments can have many different shapes and sizes depending on the event that resulted in their creation. These geometric variations can include a high-aspect, or width to thickness, ratio; however, impact from fragments with elevated aspect ratios on hardened concrete has not been extensively studied. Therefore, reinforced concrete specimens were subjected to impact from fragments with different aspect ratios to illustrate and quantify the effect of fragment characteristics, protective element features, and experimental target size on local impact performance. A novel experimental technique was developed to allow for high-aspect ratio fragment impact on concrete slabs to be evaluated. The same concrete materials were also impacted with lower aspect ratio fragments for comparative purposes. Data collected from these two experimental series were utilized to analyze the effects of compressive strength, thickness, and fiber reinforcement on impact performance. The accuracy of existing penetration and spall prediction methodologies were evaluated for both fragment types. The kinetic energy required to cause reinforced concrete to present a breached condition due to the high-aspect ratio fragment was also analyzed. Modifications were made to existing contact charge equations to account for differences between the contact charge energy required to cause a breach condition and that required from fragment impact to produce a breach condition. The breach envelope defined by these relationships was further evaluated using a computational model calibrated specifically for this impact scenario. Finally, the effect of impact specimen geometry and confinement type on target performance was numerically evaluated. Artificial and inertial confinement were examined through varying target diameter to projectile diameter ratio with and without artificial circumferential confinement. Given the minimal data associated with local effects of high-aspect ratio fragment impact and the many factors that can influence concrete impact resistance, the information and relationships learned along with the analysis techniques developed herein can be utilized to improve the state of the art of protective design.

The objective of the study was to identify the relationship between percent body fat (%BF) and waist-to-hip ratio (WHR) in children ages 7 to 9 years. The sample (n=171) was divided into four groups. Bioelectrical impedance analysis was used to estimate %BF. Significant positive correlations were observed between WHR and %BF for black females (r = 0.48), white females (r = 0.66), black males (r = 0.34), and white males (r = 0.55). Although the correlations differed between groups, the amount of variation between the two variables was not significantly different between groups other than black females. Least squares means was used to estimate %BF using an average WHR (.85). Black females had higher %BF than other groups. Percent body fat cannot be fully explained by WHR (r2 = 0.32). Results show a relationship between %BF and WHR, yet predicting %BF from a given WHR may be difficult.

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