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The Tri-State Crematory Incident in Nobel, GA (February 2001) revealed limitations in traditional human cremated remains (cremains) analytical methodology. The goal of this study was to develop a method for effectively classifying questionable sets of cremains as legitimate or contaminated. Eighty-eight samples of known human cremains, concrete, mixtures of the two, and questionable sets of cremains were acid digested and analyzed for 21 elements by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Variable cluster and principle component analyses identified the seven elements (Sb, B, Li, Mn, Sr, Tl, and V) used to develop discriminant functions to classify questionable sets into two groups: cremains and concrete. The discriminant analysis shows that at the 0.90 probability level, mixtures of 50% or less human content were classified as concrete. Mixtures with 90% human content classified as cremains. Sixty percent and 75% human content mixtures remained in the questionable classification, but as the concentration of human increased in the mixture, the probability of assignment to the known cremains group increased. Most of the questionable human samples classified as cremains. This is a pilot study and cannot yet satisfy Daubert standards for courtroom admissibility, but it indicates that it is possible to determine the legitimacy of cremains using elemental analysis by ICP-OES coupled with multivariate statistical analysis.

Composite materials have been playing a major role in modern aircraft design due to their high stiffness and strength to weight ratio. While the advantages of composite structures over their metallic counterparts is significant, it is possible to improve even further on the benefits offered by traditional composites through the use of novel composite manufacturing methods. One such method is automated fiber placement, whereby each layer of the laminate is laid up with spatially steered fiber orientations, as opposed to the traditional method, where the fiber direction is fixed for each layer. While these new "tow-steered" composites can potentially provide additional aeroelastic tailoring when applied aircraft wing design, it is not clear how to fully take advantage of this new design freedom. To address this, we use high-fidelity gradient-based aerostructural optimization to assess the relative performance of tow-steered composites compared to conventional composites, as well as aluminum. The aircraft configuration used in this work is a high aspect ratio variant of the Common Research Model (CRM). When comparing the optimal conventional composite and optimal aluminum designs we find an improvement of roughly 8.7% in fuel burn and a 39% reduction in structural weight. The tow-steered designs yield improvements of 0.4% in fuel burn and 10% in structural weight when compared to conventional composites.

In the last 30 years since their introduction into aerospace applications, composites have become increasingly used, making up as much as 50% of modern aircraft by weight. Considering this fact, it is surprising that most aircraft today are only scratching the surface of the true potential of composite technology with traditional uniaxial fibers. With the introduction of Automated Fiber Placement machines (AFP), the tow direction in laminae is now allowed to be steered spatially throughout each layer. This process is known as composite tow steering and has been shown to have improved performance over its uniaxial fiber counterpart with no additional weight penalty. With modern aircraft wings moving toward higher aspect ratios, which inevitably leads to larger deflections, it is reasonable to assume that a tow-steered composite structure can be tailored to outperform its unsteered counterpart. However, given the highly coupled nature of the aerodynamics and structural response of the problem it is not obvious nor intuitive to find the composite fiber pattern that would yield an optimum result. To address this issue, we develop a framework for the simultaneous design of aerodynamic shape, structural sizing, and tow steering angles, while considering the wing flexibility. The aerodynamics are modeled using RANS CFD, while the structure is analyzed using a detailed finite-element model. Using this framework we perform two fuel burn optimization problems are performed for a high aspect ratio (AR = 13.5) baseline wing: one using a tow-steered structure and another with no steering, unsteered. The optimization was performed with respect to tow-steering design variables, wing airfoil shapes and twist, as well as structural thicknesses. Along with including design variables which controlled the tow-steering parameterization, geometric shape variables were also included to vary the shape of the wing. The tow-steered wing was able to decrease the wing mass by 13% relative to the baseline unsteered wing.