Shock waves in graphene and boron nitride

A new manually operated pressure driven shock tube is proposed and demonstrated. Shock wave-associated parameters like velocity, Mach number, pressure, and temperature are computed using acoustic method. Experiment involves manually loading train of pressure pulses into a driver tube using a bicycle pump. The high pressure buildup in driver tube ruptures the diaphragm at critical pressure and generates a propagating shock wave in the driven section coupled with sensor section in which a couple of microphones are separated by a fixed distance. The propagating shock wave acoustical profile is recorded and its arrival time lag is measured using sound recording software. In a conventional method, piezo-electric pressure sensors are utilized to measure both pressure and time lag of shock wave between the sensors. In the proposed method, microphones are utilized to measure time lag of shock wave with sampling frequency of 768 KHz using computer supporting audio software. Utilizing time data, the said shock wave parameters are evaluated and reported. The performance of the proposed shock tube is compared with manually operated piston-driven Reddy tube.

https://link.springer.com/content/pdf/10.1007/s41314-019-0033-5.pdf

Measurement of “Shock Wave Parameters” in a Novel Table-Top Shock Tube Using Microphones

The present work is designed to investigate the impact of shock waves on Zinc Ferrite nanoparticles (ZnFe2O4) NPs. The test material was prepared by precipitation method and shock wave recovery experiment is done by tabletop pressure driven shock tube. The shock wave induced changes in structural, morphological and magnetic properties are noticed by various analytical techniques such as powder X-ray Diffractometer (PXRD), fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) and the obtained PXRD results shows no significant structural changes. Switchable paramagnetic to superparamagnetic behaviour is observed during the shock wave loaded conditions. The mechanism of shock wave induced magnetic phase transition is discussed.

Shock wave-induced switchable magnetic phase transition behaviour of ZnFe2O4 ferrite nanoparticles

In this article, we present the results of the experimental work on the impact of shockwaves on optical properties of benzyl crystallinematerial. Testmaterial of benzil crystal is grown along [100] plane by Sankaranarayana—Ramasamymethod. In the present work, the functional shockwaves ofMach number 1.7 are generated frompressure driven shock tube. The optical properties of testmaterial are investigated byUV-Visible spectrometer over the range between 200 and 800 nm. The observed results show that the intensity of the absorption spectrum is inversely proportional to the number of exposed shockwaves. The direct and indirect optical band gap energy (Eg) andUrbach tail energy (Ug) are determined from the optical absorption spectrum for pre and post shockwave loaded condition and found that shockwave loaded test crystal has high band gap energy. The optical constants namely extinction coefficient, real and imaginary parts of the dielectric constant, skin depth, optical density, optical conductivity and electrical conductivity are investigated and the obtained results are compared with post shockwave loaded benzil crystal with the incident light possessing wavelength at 700 nm. The results are found to be very impressive for the shockwave recovery experiments that are to be clearly discussed.

Shock wave induced enhancement of optical properties of benzil crystal

The present work is focused on stability of shock wave-exposed copper oxide (CuO) nanoparticles. CuO nanoparticles are synthesized by chemical reduction method and exposed to 100 shock pulses having Mach number 2.4. The table top semiautomatic pressure-driven shock tube is used to generate shock waves for the present experiment. The influence of shock waves on the treated and untreated CuO nanoparticles are explored and characterized by a variety of properties like structural, molecular and morphological details observed using powder XRD, FTIR and SEM, respectively. The powder XRD profile confirmed that there are no lattice defects or any deformation except negligible changes in grain size. SEM images established that the shock wave-loaded CuO nanoparticles have good structural and morphological stability. The obtained results showed that CuO nanoparticles can be used in aerospace, nuclear reactors and high-pressure applications which undergo extreme conditions. The details are presented intensely in the following sections.

/pdf/influence-of-shock-waves-on-structural-and-morphological-467fr1nmm4.pdf

Influence of shock waves on structural and morphological properties of copper oxide NPs for aerospace applications

An alternative non-destructive approach is proposed and demonstrated for modifying electrical properties of crystal using shock-waves. The method alters dielectric properties of a potassium dihydrogen phosphate (KDP) crystal by loading shock-waves generated by a table-top shock tube. The experiment involves launching the shock-waves perpendicular to the (100) plane of the crystal using a pressure driven table-top shock tube with Mach number 1.9. Electrical properties of dielectric constant, dielectric loss, permittivity, impedance, AC conductivity, DC conductivity and capacitance as a function of spectrum of frequency from 1 Hz to 1 MHz are reported for both pre- and post-shock wave loaded conditions of the KDP crystal. The experimental results reveal that dielectric constant of KDP crystal is sensitive to the shock waves such that the value decreases for the shock-loaded KDP sample from 158 to 147. The advantage of the proposed approach is that it is an alternative to the conventional doping process for tailoring dielectric properties of this type of crystal.

J. Anto Pradeep

Papers

Effect of Shock Waves on Dielectric Properties of KDP Crystal

Study on mechanical characteristics of the nano-TiC reinforced Al6061 metal matrix composites