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Abhijit Sarkar

Bio: Abhijit Sarkar is an academic researcher from Indian Institutes of Technology. The author has contributed to research in topics: Polydiacetylenes & Conjugated system. The author has an hindex of 2, co-authored 6 publications receiving 8 citations.

Papers
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Journal ArticleDOI
20 Jan 2020
TL;DR: In this article, the blades of propellers, fans, compressor and turbines are modeled as curved beams and the finite element method is employed to determine the modal characterist of the blades.
Abstract: The blades of propellers, fans, compressor and turbines can be modeled as curved beams. In general, for industrial application, finite element method is employed to determine the modal characterist...

4 citations

Book ChapterDOI
01 Jan 1991
TL;DR: In this paper, the authors proposed Polydiacetylenes (PDAs) as a candidate material for third-order non-linear optical properties (χ 3) due to the fact that PDAs show large third order nonlinear optical susceptibility with a fast response time.
Abstract: Recently, there has been hectic research activity in search of organic materials which show promising non-linear optical properties.1–5 Polydiacetylenes (PDAs) attracted special attention as a candidate material for third order non-linear optical properties (χ 3). This interest is due to the fact that PDAs show large third order non-linear optical susceptibility, with a fast response time. Additional supporting and important features of PDAs are that they can be obtained in single crystal form or LB films and it is possible to tune their optical properties through “Molecular and crystal engineering” through a variety of sidegroups.

2 citations

Journal ArticleDOI
TL;DR: In this article, two symmetrical diacetylene monomers containing thienyl moiety as the side groups, namely 1,4-bis(2'-thienyl)butadiyne and 1, 4-bis (3'-thiamyl) butadiynes, are reported which have been successfully polymerised electrochemically.
Abstract: Two symmetrical diacetylene monomers containing thienyl moiety as the side groups, namely 1,4-bis(2'-thienyl)butadiyne and 1,4-bis(3'-thienyl)butadiyne, are reported which have been successfully polymerised electrochemically. They have also been polymerised chemically in solution using Lewis acid as initiator. The resulting polymers have been characterised by elemental analysis, infrared spectra, absorption spectra and by solid state NMR spectra. The polymers were found to have conjugated π-electron structure and both of them show high environmental stability. The properties of the polymers have been compared with that of poly(3-methylthiophene) which is a conventional and much studied conjugated polymer. The electrical conductivity of the polymers has also been investigated.

2 citations

Journal ArticleDOI
TL;DR: In this article, the authors examined risk sensitivity of Indian banks' subordinated debt (SND) spreads (primary market) to ascertain whether debt investors act as a disciplinarian by discriminating across banks based on risk.
Abstract: Though Basel II has been adopted by many emerging economies and guidelines on Market Discipline have been issued, question may be raised as to what extent market can act as an effective disciplinary force in these immature financial markets. This paper examines risk sensitivity of Indian banks' subordinated debt (SND) spreads (primary market) to ascertain whether debt investors act as a disciplinarian by discriminating across banks based on risk. A unique dataset of SND issues is compiled from issue documents filed with National Stock Exchange (NSE) at the time of issue/listing. The dataset includes issues listed with NSE as on 31st August 2007 and covers the period March 1999 to July 2007. Significant issue clustering in the highest rating-low risk categories is observed, both in terms of number and aggregate issue size. The pooled panel OLS results suggest sort of equi-spread clustering along the rating scale giving rise to a step-wise weakly monotonous increase in spread with enhanced issue risk. Dominance by government owned Public sector banks (PSB) in the SND market considerably weakens market discipline. The spread on PSB SND issues are generally lower relative to Private issues in the same rating scale. Even though more than half of the SNDs were issued over the last 28 months of the data period, no increased risk sensitivity of spreads is noticed. Issue ratings perform better as risk proxy relative to accounting measures of risks. Overall, market disciplinary role of the Indian SND market participants proves to be rather weak.

1 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, photo-induced radical homopolymerization of MIThi and its copolymerization with styrene were performed at room temperature to give linear polymers containing pendant thienyl moieties using ω,ω-dimethoxy-ω-phenylacetophenone as an initiator.
Abstract: Two types of novel functionalized N-[4-(4′-hydroxyphenyloxycarbonyl)phenyl]maleimide and N-(4-{[2-(3-thienyl)acetyl]oxyphenyl}oxycarbonylphenyl)maleimide (MIThi) were synthesized starting from 4-maleimido benzoic acid. Photoinduced radical homopolymerization of MIThi and its copolymerization with styrene were performed at room temperature to give linear polymers containing pendant thienyl moieties using ω,ω-dimethoxy-ω-phenylacetophenone as an initiator. Copolymers' compositions and the equilibrium constant (K) for electron donor–acceptor complex formation suggest an alternating nature of the copolymerization. The monomer reactivity ratios and Alfrey–Price Q,e values were also determined. The thermal behavior of the new synthesized monomers and polymers was investigated by differential scanning calorimetry and thermogravimetric analysis. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 995–1004, 2002

24 citations

Journal ArticleDOI
TL;DR: In this article, a layered periodic curved beam (LPCB) concept was introduced to minimize the effect of peak attenuation at a specific narrow frequency range within the attenuation band or disintegrates it into two bands.

14 citations

Journal ArticleDOI
TL;DR: In this article, the same authors showed that conduction proceeds without the help of the links via a direct redox hopping between sexithiophene blocks of adjacent polymer chains, and that the polymers obtained are characterized by cyclic voltammetry, EQCM, UV−vis, and FTIR spectroscopy, in situ ESR and in situ conductivity.
Abstract: Electrochemical oxidation of bis-terthienyl-B (B = ethane, disulfide, diacetylene, acetylene, ethylene) has been investigated. Monomers without and with 3,3′′-dialkylsubstitution are regularly coupled to polymers alternating sexithiophene and B moieties. The corresponding terthienyl homopolymers have also been produced for comparison. The polymers obtained are characterized by cyclic voltammetry, EQCM, UV−vis, and FTIR spectroscopy, in situ ESR and in situ conductivity. The conductivities of p-doped polymers with ethane or disulfide bridges fall in a narrow range (1−5 × 10−2 S cm−1) and are practically the same as those of α,ω-dimethylsexithiophene (1 × 10−2 S cm−1), suggesting that conduction proceeds without the help of the links via a direct redox hopping between sexithiophene blocks of adjacent polymer chains. In the cases of diacetylene and acetylene, conduction changes from redox to bipolaron-type but only in the case of ethylene the conductivity jumps to high values (1−5 S cm−1) corresponding to th...

12 citations

Journal ArticleDOI
TL;DR: In this paper, the elastic wave propagation and dispersion characteristics of a curved tapered frame structure were investigated analytically, and it was shown that a small periodic bent angle cross-section produces a complete, viz. axial and flexural band gap in the low-frequency region, and conicity enhances the width of the band.
Abstract: In this work, the elastic wave propagation and dispersion characteristics of a curved tapered frame structure is investigated analytically. Separately, wave propagation through uniform curved and straight tapered beam were reported in the existing literature; however, no literature reports the influence of simultaneous bent and taper on the wave propagation. In particular, the band characteristics for the curved and tapered beam with two types of cross-sections, i.e., rectangular and circular, are presented. The paper elucidates that introducing a small periodic bent angle cross-section produces a complete, viz. axial and flexural band gap in the low-frequency region, and conicity enhances the width of the band. It is also evidenced that a curved tapered frame with a solid circular cross-section induces a wider band gap than the rectangular section. A complete first normalized bandwidth of 159% is achievable for the circular cross-section and 123% in the case of the rectangular section. The complete result is presented in a non-dimensional framework for wider applicability. An analysis of a finite tapered curved frame structure also demonstrates the attenuating characteristics obtained from the band structure of the infinite structure. The partial wave mode conversion, i.e., generation of coupled axial and flexural mode from a purely axial or flexural mode in an uncoupled medium is observed. This wave conversion is perceived in reflected and transmitted waves while this curved tapered frame is inserted between the two uniform cross-section straight frames.

6 citations

Journal ArticleDOI
TL;DR: In this article, the 4-bis(1-naphthyl)-buta-1,3-diyne (C24H14, Mr,'302.38, monoclinic, P2 1/a, a '7.534', b'6.012(1), c'17.969(3)A, β' 101.67 A, Dx'1.257g/cc, F(000)'316, λ.(Mok)α'0.71073 A T '300 K,
Abstract: 1, 4-bis(1-naphthyl)-buta-1,3-diyne, C24H14, Mr , ' 302.38, monoclinic, P2 1/a, a '7.534(1), b ' 6.012(1), c ' 17.969(3)A, β' 101.1(1)˚, V ' 798.67 A, Dx ' 1.257g/cc, F(000) ' 316, λ.(Mok)α ' 0.71073 A T '300 K, final R and wR are 0.0389 and 0.0457 respectively using 1281 reflections taken in least squares calculations.

4 citations