Nondestructive impact

It is often possible to address function more specifically in in vitro assays, where functional parameters are usually very sensitive readouts of adverse effects. For example trans-epithelial electrical resistance (TEER) is a very sensitive marker of epithelial disturbances. TEER measures the barrier function of the entire mono-layer and is utilized to study functional disturbances of many epithelial/endothelial cell types including blood-brain barrier, pulmonary, renal, and gastrointestinal cells. Its sensitivity lies in the fact that only a small proportion of cell death has a very large impact on barrier function. Additionally, cell stress can interfere with the arrangement and population of tight junction proteins [16] thus, TEER can in certain conditions measure functional disturbances in the absence of cell death [13]. Also since TEER can be measured noninvasively, it is nondestructive and can be used to monitor the effects of treatment over days and weeks [13, 17]. For excitable cells, electrical activity has also been proven to be an extremely sensitive parameter of adverse drug reactions and microelectrode arrays have been employed successfully to monitor neurotoxicity in vitro [18]. Also, for contractile cells, such as cardiomyocytes, the use of impedance measurements to measure the effects of compounds on spontaneous contraction has been demonstrated to be a very sensitive functional monitoring parameter in vitro [19, 20], Admittedly, none of the aforementioned techniques are true biomarkers per se however, such measurements illustrate the fact that in vitro techniques allow certain possibilities that are not practically tenable in the whole body. 

M.J. Sansalone, and W.B. Street, Impact-Echo Nondestructive Evaluation of Concrete and Masonry, Bullbrier Press, Ithaca, NY, 1997. 

Hardness measurements are not always truly nondestructive, and much depends on the particular method chosen. A special method that does not cause any damage has been reported but not described in detail (48), but other methods may leave some dents or needle holes (47), The latter, although quite unacceptable in some cases, might be considered virtually nondestructive in particular situations, especially with larger objects. An example is the survey conducted on timbers of the Mary Rose using a needle impact hardness tester (Pilodyn instrument) (41). 

W. H. Green, J. M. Wells, Nondestructive characterization of impact damage in metallic/nonmetallic composites using X-ray computed tomography imaging, NASA ARL-TR-2399, February 2001. 

Dams R, Rahn KA, Winchest JW (1972) Evaluation of filter materials and impaction surfaces for nondestructive neutron activation analysis of aerosols. Environ Sci Technol 6 441-448... 

Chlorophyll fluorescence has been used as an accurate and nondestructive probe of photosynthetic efficiency, which can directly or indirectly reflect the impacts of environmental factors and changes in the physiological state of the plants (Baker, 2008, as cited in Falco et al., 2011). Recently, the first in vivo observation of chlorophyll fluorescence... 

Radford. D.. Ganchev. S.. Qaddoumi. N.. Beauregard. G.. and Zoughi. R. (1994). Millimeter wave nondestructive evaluation of glass fiber epoxy composites subjected to impact fatigue. Proc. of the SPIE. Advanced Microwave and Millimeter-Wave Detectors Conf.. Vol. 2275. 

With the recent collapse of two posttensioned bridges in the United Kingdom and one in Belgium the impact-echo nondestructive evaluation (NDE) technique was developed to detect voids in posttensioned ducts. In addition, a complementary magnetic-based nondestmctive technique (NDT) for assessing section loss in... 

Mode I cyclic compression—compression tests on CFRP-impacted CFRP plates have been performed by Katerelos et al. [38]. The analysis relies on nondestructive testing (ultrasonic C-scan) and modelling for quantification of delamination resistance. In mode II tests, there is a choice between test parameters yielding no shear reversal or... 

FAA. Impact damage characterization and damage tolerance of composite sandwich airframe structures — phase II. DOT/FAA/AR-02/80 Final Report October 2002. Workman GL, Kishoni D. Ultrasonic testing. 3rd ed. American Society for Nondestructive Testing 2007. 

Impact Nondestructive Plaque-foam helmet surrogate... 

ANTHONY G. EVANS is the Gordon McKay Professor of Materials Engineering at Harvard University. His research interests include the mechanical properties of brittle materials particularly the fracture of ceramics under conditions of impact thermal and mechanical stress and failure prediction based on nondestructive evaluation. He is a recipient of the American Ceramic Society s Ross ColEn Purdy Award and has authored and co-authored several publications. Dr. Evans is a member of the National Materials Advisory Board and has served on several National Research Council committees. Dr. Evans was elected to the National Academy of Engineering in 1997 for his contributions to the development and understanding of structural materials. 

J H Starnes, M D Rhodes and J G Williams, Effect of impact damage and holes on compressive strength of a graphite/epoxy laminate . Nondestructive Evaluation and Flaw Criticality for Composite Materials, ASTM STP 696,1979, pp 145-171. 

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