349 research outputs found
Micro-crack detection in CFRP laminates using coda wave NDE
Get PDFCoda Waves or diffuse field has been touted to be an NDE method that does not require the damage to be in the path of the ultrasound. The object is insonified with ultrasound and instead of catching the first or second arrival, the waves are allowed to bounce multiple times. This aspect is very important in structural health monitoring (SHM) where the potential damage development location is unknown. Researchers have used Coda waves in the interrogation of seismic damage and metallic materials. In this work we have applied the technique to composite material, and present the results herein. The coda wave and acoustic emission signals are recorded simultaneously and corroborated. Development of small incipient damage in the form of micro-crack and their detection is the objective of this work.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
This proceeding appeared in Dayal, Vinay, Dan Barnard, and Richard Livings. "Micro-crack detection in CFRP laminates using coda wave NDE." In AIP Conference Proceedings, vol. 1949, no. 1, p. 210001. AIP Publishing LLC, 2018., and may be found at
DOI: 10.1063/1.5031644.
Copyright 2018 The Author(s).
Posted with permission
Occurrence and fate of aromaticity driven recalcitrance in anaerobic treatment of wastewater and organic solid wastes
No full textAromatic compounds such as aromatic amines (AAs) or lignocellulose biomass derivatives are often recalcitrant to biological processes (i.e., anaerobic digestion). The level of recalcitrance is usually explained by the biochemical structure of the compounds, which determines their removal. AAs are present in dye wastewaters mainly originated from textile industries and are considered carcinogenic and challenging pollutants to be removed from wastewater. The hydrolysis of lignin leads to the formation of some aromatic compounds, which could be recalcitrant at certain concentrations and operation conditions. Similarly, derivatives from sugar degradation such as furfurals and 5-hydroxymethylfurfural (HMF) from pentose and hexose degradation, respectively, have also been reported to be recalcitrant to anaerobic treatment. This chapter details the different forms of recalcitrance found and/or formed during wastewater and organic solid waste treatment, particularly in the anaerobic digestion process. Moreover, the possible strategies to mitigate the recalcitrance of these compounds are comprehensively explained.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Sanitary Engineerin
To Collect Their Shattered Energies : Hammond Hospital and Military Mental Healthcare during the Civil War
Get PDFAbout the author Vinay Giri is a Biology major at Duke University. While taking a global health class that explored the evolution of science and technology worldwide, he became very interested in the history of medicine. Vinay’s research was conducted in Beaufort, NC at the Duke Marine Lab.
Development of composite calibration standard for quantitative NDE by ultrasound and thermography
Get PDFInspection of aircraft components for damage utilizing ultrasonic Non-Destructive Evaluation (NDE) is a time intensive endeavor. Additional time spent during aircraft inspections translates to added cost to the company performing them, and as such, reducing this expenditure is of great importance. There is also great variance in the calibration samples from one entity to another due to a lack of a common calibration set. By characterizing damage types, we can condense the required calibration sets and reduce the time required to perform calibration while also providing procedures for the fabrication of these standard sets. We present here our effort to fabricate composite samples with known defects and quantify the size and location of defects, such as delaminations, and impact damage. Ultrasonic and Thermographic images are digitally enhanced to accurately measure the damage size. Ultrasonic NDE is compared with thermography.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
This proceeding appeared in Dayal, Vinay, Zach G. Benedict, Nishtha Bhatnagar, and Adam G. Harper. "Development of composite calibration standard for quantitative NDE by ultrasound and thermography." In AIP Conference Proceedings, vol. 1949, no. 1, p. 060006. AIP Publishing LLC, 2018, and may be found at
DOI: 10.1063/1.5031552.
Copyright 2018 The Author(s).
Posted with permission
Online Teaching amidst COVID-19 in India: An Outlook
No full textThe lockdown imposed in India on 25 March 2020 resulted in the indefinite closure of education institutes all across the country. The government and educational institutes were quick to respond, they shifted teaching from offline to online mode. This article aims to identify the approaches made by the higher education institutions for continues imparting of education amidst lockdown. The article also identifies the challenges faced by teachers in online teaching from their homes. The study is descriptive and analytical in nature and data has been collected from secondary sources like reports, news articles, blogs, interview videos, magazines, social media, and journals to achieve the objective of the paper. Based on the secondary sources' information, the article also advocates the learning curve for the future to deal with any such crisis impact on the education system of India. The findings revealed that higher education institutions (HEIs) have taken many initiatives in this pandemic situation for imparting education. But these initiatives have not been very successful from the teacher's perspective. Teachers faced may issue in online teaching such as lack of technical facilities, family interruption, lack of training, lack of clarity & direction, lack of technical knowledge. The learning curve of the article facilitates the HEIs to help them to execute the online educative in an effective manner.Joshi, A., Vinay, M., & Bhaskar, P. (2020). Online Teaching amidst COVID-19 in India: An Outlook. Asian Journal of Distance Education, 15(2), 105-111. https://doi.org/10.5281/zenodo.429447
A critical assessment of technical advances in pharmaceutical removal from wastewater – A critical review
Get PDFUse of pharmaceutical products has seen a tremendous increase in the recent decades. It has been observed that more than thirty million tons of pharmaceuticals are consumed worldwide. The used pharmaceutical products are not completely metabolized in human and animal body. Therefore, they are excreted to the environment and remain there as persistent organic chemicals. These compounds emerge as toxic contaminants in water and affect the human metabolism directly or indirectly. This literature review is an endeavour to understand the origin, applications and current advancement in the removal of pharmaceuticals from the environment. It discusses about the pharmaceuticals used in medical applications such diagnosis and disease treatment. In addition, it discusses about the recent approaches applied in pharmaceutical removal including microbial fuel cells, biofiltration, and bio nanotechnology approaches. Moreover, the challenges associated with pharmaceutical removal are presented considering biological and environmental factors. The review suggest the potential recommendations on pharmaceutical removal.The corresponding author Prof. Vinay Kumar is thankful to all the co-authors for their collaborative efforts in writing this paper. This work was supported by Department of Community Medicine, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, India.Peer reviewe
Characterization of 3D rapid prototyped polymeric material by ultrasonic methods
Get PDFRapid prototyped parts are quickly becoming a viable alternative for manufacturers. Although the polymeric material is initially isotropic, the printing process introduces a level of anisotropy. This work characterizes the elastic and acoustic properties of the material, after printing, using ultrasonic methods. The elastic constants and the level of anisotropy are determined by measuring the ultrasonic wave velocities. It is shown that the material possesses less symmetry than the orthotropic material model. The dispersion and attenuation characteristics are also determined to provide a basis for ultrasonic flaw detection.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
This proceeding appeared in Livings, Richard, Vinay Dayal, and Dan Barnard. "Characterization of 3D rapid prototyped polymeric material by ultrasonic methods." In AIP Conference Proceedings, vol. 1650, no. 1, pp. 807-816. American Institute of Physics, 2015, and may be found at
DOI: 10.1063/1.4914684.
Copyright 2015 AIP Publishing LLC.
Posted with permission
Ultrasonic time-of-flight shift measurements in carbon composite laminates containing matrix microcracks
Get PDFTime-of-flight (TOF) shifts are calculated from the fundamental A0 Lamb mode using air-coupled ultrasound. The technique is applied to carbon/bismaleimide samples containing varying microcrack density along the length of the sample. The phase and group velocity reduction is inferred from the TOF shift data. The relation between group velocity and crack density is presented. Approximate microcrack densities over several segments of the sample are calculated using a simple constant thresholding algorithm applied to X-ray MicroCT data.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
This proceeding appeared in Subramanian, Ajith, Vinay Dayal, and Daniel J. Barnard. "Ultrasonic time-of-flight shift measurements in carbon composite laminates containing matrix microcracks." In AIP Conference Proceedings, vol. 1581, no. 1, pp. 1098-1105. American Institute of Physics, 2014, and may be found at
DOI: 10.1063/1.4864943.
Copyright 2014 AIP Publishing LLC.
Posted with permission
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No full textIn a publication on current science, an author is included whose author, Olivier Postel-Vinay (2003), following the opinion of what he calls "a surgeon of the spirit", Adolf Grübaum, questions the relevance of the Freudian discovery.En una publicación sobre la actualidad de la ciencia se incluye un artícilo cuyo autor, Olivier Postel-Vinay (2003), siguiendo la opinión de quien él llama "un cirujano del espíritu", Adolf Grübaum, cuestiona la pertinencia del descubrimiento freudiano.Em uma publicação sobre a ciência atual, é incluído um autor cujo autor, Olivier Postel-Vinay (2003), seguindo a opinião do que ele chama de "cirurgião do espírito", Adolf Grübaum, questiona a relevância da descoberta freudiana
Experimental setups for studying homogeneous-isotropic and rotating turbulence in clay suspensions: Preliminary results
Get PDFHomogeneous and isotropic turbulence (HIT) has been at the center of a vast span of research seeking fundamental understanding and insights on the phenomenon of turbulence, which is ubiquitous in nature as well as engineering. The HIT assumption greatly simplifies the analytical treatment of turbulence, however creating truly HIT conditions in experiments has still remained a challenge and most research has focused on Newtonian fluids. Here we uses two different approaches to create HIT in water and aqueous suspension of Laponite clay, a shear-thinning fluid. The first approach involving flow actuators placed symmetrically around an enclosed volume has been used by past studies for creating small regions of HIT in gaseous media. We show using planar particle image velocimetry that our HIT setup is capable of producing low Taylor microscale Reynolds number HIT region of 20 mm x 20 mm in liquid media. Comparison of temporal spectra in water and aqueous clay suspension cases showed that presence of clay significantly alters the scaling of the inertial subrange and increases the Taylor microscale Reynolds number, in addition to suppressing the mean flow. The second approach uses random actuation of jets to stir fluid in a tank, which has been used by past studies to create large HIT regions. We have built a smaller version of this concept with the aim to create high Taylor microscale Reynolds number flow in water and clay suspensions.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2022-05-01The student, Vaibhav Vinay Tipnis, accepted the attached license on 2020-05-08 at 16:14.The student, Vaibhav Vinay Tipnis, submitted this Thesis for approval on 2020-05-08 at 16:39.This Thesis was approved for publication on 2020-05-13 at 07:30.DSpace SAF Submission Ingestion Package generated from Vireo submission #15303 on 2020-08-25 at 17:30:47Made available in DSpace on 2020-08-26T23:58:45Z (GMT). No. of bitstreams: 2
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