BazTech - Yadda

1

Synthesis and characterization of poly(p-phenylenediamine): TiO2 nanocomposites and investigation of conducting properties for optoelectronic application

Baruah S., Devi N., Puzari A.

Materials Science Poland

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2020

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Vol. 38, No. 2

296--304

EN

Poly(p-phenylenediamine) is a potential precursor for designing of new materials for optoelectronic application. Synthesis and characterization of poly(p-phenylenediamine) – TiO2 nanocomposites has been demonstrated. Structural change observed due to the formation of nanocomposites was correlated with concomitant change in conducting behavior of the parent polymer. Polymer nanocomposite was synthesized through an in-situ oxidative polymerization technique with simultaneous dispersion of TiO2 nanoparticles. TiO2 nanoparticles were synthesized via sol-gel process. Structural characterization was accomplished by using conventional spectroscopic and imaging techniques. I-V measurement of the nanocomposites revealed that the nearly nonconducting poly(p-phenylenediamine) after structural modification exhibits conductivity of 10-6 S/cm leading to formation of wide band gap semiconducting materials.

2

Shear Wave Velocity Estimates through Combined Use of Passive Techniques in a Tectonically Active Area

Biswas R., Baruah S.

Acta Geophysica

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2016

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Vol. 64, no. 6

2051--2076

EN

We made an attempt to assess the shear wave velocity values VS and, to a lesser extent, the VP values from ambient noise recordings in an array configuration. Five array sites were situated in the close proximity to borehole sites. Shear wave velocity profiles were modeled at these five array sites with the aid of two computational techniques, viz. spatial autocorrelation (SPAC) and H/V ellipticity. Out of these five array sites, velocity estimates could be reliably inferred at three locations. The shear wave velocities estimated by these methods are found to be quite consistent with each other. The computed VS values up to 30 m depth are in the range from 275 to 375 m/s in most of the sites, which implies prevalence of a low velocity zone at some pocket areas. The results were corroborated by evidence of site geology as well as geotechnical information.

3

Influence of attenuation and site on microearthquakes’ spectra in Shillong region, of northeast, India: A case study

Biswas R., Baruah S., Bora D.

Acta Geophysica

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2013

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Vol. 61, no. 4

886--904

EN

We examine the influence of attenuation and site on the spectra of microearthquakes having origin within the Shillong region. The ratios of spectral amplitudes at lower and higher frequencies are measured for three different stations at varying epicentral distances to estimate Q value for both P- and S-wave in near and sub-surface layer. The average estimates of QP and QS are found to be 178 and 195. The ratio of QS to QP emerges to be greater than unity in major parts of the Shillong area, suggesting dominance of dry crust prevailing in Shillong region. The variation in corner frequencies for these spectra is inferred to be characteristics of the site. Besides, the disparity in spectral content with reference to hard rock site yields the inference that the incoming seismic signals get amplified considerably while traversing from southern part to northeastern part of Shillong, best outlined at 2 to 5 Hz, which is well corroborated by the existing lithology.