Air gaps entrapped in protective clothing are known as one of the major factors affecting heat transfer through multiple layers of flexible clothing fabrics. The identification and quantification of the air gaps are two aspects of a multidisciplinary research effort directed toward improving the flame/thermal protective performance of the clothing. Today's three-dimensional (3-D) whole body digitizers, which provide accurate representations of the surface of the human body, can be a novel means for visualizing and quantifying the air gaps between the wearer and his clothing. In this paper we discuss how images from a 3-D whole body digitizer are used to determine local and global distributions of air gaps and the quantification of air gap sizes in single and multilayer clothing systems dressed on a thermal manikin. Examples are given that show concordance between air gap distributions and burn patterns obtained from full-scale manikin fire tests. We finish with a discussion of the application of air gap information to bench-scale testing to improve the protective performance of current flame/thermal protective clothing.
The present study was undertaken to provide a quantitative description of craniofacial growth in Cebus apella in three dimensions. Landmarks from a cross-sectional sample of sexed and dentally aged crania were collected using a 3Space digitizer. Two methods of three-dimensional form analysis, euclidian distance matrix analysis (EDMA) and finite-element scaling analysis (FESA), were used to investigate growth changes in the cranium. Male and female growth was examined by comparing the youngest male mean form to all other age/sex specific mean forms. In addition, form differences between the sexes were studied by comparing male and female mean forms at each age. The cranium was divided into four regions for analysis: muzzle, upper face, neurocranium, and basicranium. Growth changes within each region were examined. In the muzzle and neurocranium, most growth occurs along the anteroposterior axis. Growth around pterion and the lower orbital rim is prominent within the upper face. The basicranium shows a surprisingly large amount of form change with growth. This form change is due to the mediolateral expansion of the basioccipital, and to the posterior migration and inferior rotation of basion. Males and females have similar growth patterns, but males tend to be larger than females in nearly all dimensions at every developmental age except the youngest. Evidence suggests that craniofacial sexual dimorphism is primarily due to males growing faster than females for approximately the same amount of time.
Improvements in data gathering technology have made it possible to quickly and accurately digitize large numbers of objects. The three dimensional coordinates of 44 homologous landmarks were obtained from a sample of 104 squirrel monkey (Saimiri sciureus) crania. After sorting by sex, the crania were assigned to one of four dental age groups. Two quantitative methods, Euclidean distance matrix analysis (EDMA) and finite element scaling analysis (FESA), were used to study craniofacial form change during growth within each sex. Form differences between the sexes at each developmental age were also examined. Both sexes show a small amount of cranial growth overall; however, there are areas of substantial local growth. These areas include the anterior neurocranium and basicranium, the basioccipital, and the anterior palate. Sexual dimorphism in the craniofacial complex is minimal. The most dimorphic regions are the orbitonasal portion of the lower face, the cranial base, and the palate.
Correlation coefficients and SEE results for this sample were: (1) DXA vs 3DS; r = 0.74, SEE = 3.2, (2) MA vs DXA; r = 0.82, SEE = 2.8, and (3) MA vs 3DS; r = 0.96, SEE = 1.0. Lin's concordance analysis, including Bland-Altman limits of agreement (LOA), revealed statistically significant measurement agreement among the three measurement modalities (p < 0.05). The application of 3DS scanning to estimate percent BF from commonly used anthropometric measurements are in close agreement with BF estimates derived from analogous MA measurements and from DXA scanning.
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