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Commonly used methods for defect localization in structures are based on velocity differences (VD) or amplitude ratio (AR) (or attenuation due to scattering) measured along different sensing paths between a reference system and a defective system. A high value on a sensing path indicates a higher probability of the presence of defect on that path. We introduce an alternative approach based on the newly developed topological acoustic (TA) sensing technique for localizing defects in plate structures using Lamb waves. TA sensing exploits changes in geometric phase of acoustic waves to detect perturbations in the supporting medium. This approach uses a geometric phase change – index (GPC-I), a measure of the geometry of the acoustic field averaged over a spectral domain, as detection metric in lieu of VD or AR. Calculations based on the finite element method (FEM) in Abaqus/CAE software verifies the effectiveness of the proposed GPC-I-based defect localization method. Randomly located defects on the surface of a plate are localized with higher sensitivity and accuracy, by the GPC-I method in comparison to VD or AR-based methods.
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Spectrophotometric Method for the Quantification and Kinetic Evaluation of in vitro c-di-GMP Hydrolysis in the Presence and Absence of Oxygen
A spectrophotometric method to measure hydrolysis of the bacterial second messenger cyclic dimeric guanosine monophosphate is described for characterization of enzymes under aerobic and anaerobic conditions. The method allows for obtaining all necessary data to calculate KM and kcat from reactions within a single 96-well plate that be can measured using a standard plate reader. The spectrophotometric assay has been used to measure the rates and obtain Michaelis-Menten for the c-di-GMP phosphodiesterase DcpG with the sensor domain in various ligation states.
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- Award ID(s):
- 2003350
- PAR ID:
- 10476104
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Methods in molecular biology
- ISSN:
- 1940-6029
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/978-1-0716-3080-8_7
