Characterisation of Microstructure, Texture and Mechanical Properties in Ultra Low-Carbon Ti-B Microalloyed Steels

R. Shukla,S. K. Ghosh,D. Chakrabarti,S. Chatterjee 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.1

In the present study, thermo-mechanical controlled processing followed by water quenching has been utilisedto produce ultra low-carbon microalloyed steel in a laboratory scale. The variation in microstructure andcorresponding mechanical properties at the selected range of finish rolling temperatures (FRT), (850-750 °C)has been evaluated. The microstructures of the steels consisted of polygonal ferrite, acicular ferrite as well asgranular bainite with the average ferrite grain sizes less than 5 μm. Finish rolling at 850°C produced weaktexture. α-fibre and γ-fibre intensified with the decrease in finish rolling temperature to 800°C. Intensitiesof the beneficial texture components such as, {554}<225> and {332}<113> also reached the highest valueat 800°C. Ferrite deformation texture i.e. α-fibre dominated at 750°C FRT. The characteristic ferrite - bainitemicrostructure with fine ferrite grain size and uniform distribution of fine TiC particles (< 50 nm) resulted inhigh yield strength (405-507 MPa), moderate tensile strength (515-586 MPa) and high total elongation (19-22%)for the selected range of finish rolling temperatures. Fairly good impact toughness value in the range of 63-74Jwas obtained at subzero temperature (-40 °C) in the sub-size sample. The above strength - ductility - toughnesscombination boosts the potentiality of developed steel for the pipeline application.

Associations of CYP1A1, GSTM1 and GSTT1 Polymorphisms with Lung Cancer Susceptibility in a Northern Indian Population

Shukla, R.K.,Tilak, A.R.,Kumar, C.,Kant, S.,Kumar, A.,Mittal, B.,Bhattacharya, S. Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5

Background: Susceptibility to lung cancer has been shown to be modulated by inheritance of polymorphic genes encoding cytochrome P450 1A1 (CYP1A1) and glutathione S transferases (GSTM1 and GSTT1), which are involved in the bioactivation and detoxification of environmental toxins. This might be a factor in the variation in lung cancer incidence with ethnicity. Materials and Methods: We conducted a case-control study of 218 northern Indian lung cancer patients along with 238 healthy controls, to assess any association between CYP1A1, GSTM1 and GSTT1 polymorphisms, either separately or in combination, with the likelihood of development of Lung cancer in our population. Results: We observed a significant difference in the GSTT1 null deletion frequency in this population when compared with other populations (OR=1.87, 95%CI: 1.25-2.80-0.73, P=0.002). However, GSTM1 null genotype was found associated with lung cancer in the non-smoking subgroup. (P=0.170). Conclusions: Our study showed the GSTT1 null polymorphism to be associated with smoking-induced lung cancer and the GSTM1 null polymorphism to have a link with non-smoking related lung cancer.

Development of Nanoparticle-Based High Current Density Cathode for THz Devices Application

Barik, R. K.,Singh, A. K.,Shukla, S.,Singh, T. P.,Raju, R. S.,Park, G.-S Institute of Electrical and Electronics Engineers 2016 IEEE transactions on electron devices Vol.63 No.4

<P>Scandia (Sc2O3)-doped tungsten nanoparticle-based high current density cathode is developed for the application in terahertz (THz) devices. This paper involves synthesis of scandia-doped tungsten nanoparticle powder using chemical technique, estimation of optimum porosity, and development of pellet with required porosity by optimizing process parameters. The cathode, made out of the above pellet, is tested in an analytical system containing Auger electron spectroscope and anode. The results show that the cathode can deliver more than 100 A/cm(2) current density with stable emission-strongly recommending it as a candidate for the use in a THz device. Theoretical estimates show that the void porosity is to be kept at 21% for proper surface coverage to produce good emission with long life.</P>

Impedance and modulus spectroscopy characterization of La^+3/Mn^+4 modified PbTiO_3 nanoceramics

Archana Shukla,R.N.P. Choudhary 한국물리학회 2011 Current Applied Physics Vol.11 No.3

Nanocrystalline samples of Pb_0.92La_0.08Mn_xTi_(1-x)O_3 (PLMT) (x = 0, 0.04, 0.07, 0.10) were prepared by a high-energy ball-milling followed by a solid-state reaction method. Preliminary high resolution X-ray diffraction technique of PLMT ceramics showed that a single-phase was formed exhibiting a tetragonal crystal structure. The electrical behavior of PLMT ceramics was investigated by the impedance spectroscopy in the temperature range of 35 ℃―500 ℃. This study was carried out by means of the simultaneous analysis of the complex impedance (Z^*) and electrical modulus (M^*) functions from the measurement range of 1 kHz―1 MHz. A separation of the grain and grain boundary properties has been achieved using an equivalent circuit model in impedance analysis. Loss spectra reveal about the presence of temperature-dependent electrical relaxation phenomena in the materials. Modulus analysis provides wider information related to charge transport processes.

An Approach to Develop a Compact Transmission Line Tower with Special 8-Legged Confi guration

Veerendra K. Shukla,M. Selvaraj,R. Ramesh Babu 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.1

For transmission of electricity from power generation plant to substations, many types of structures are being used. The main function of these structures is to support the power conductors and earth-wire. 4-legged steel lattice tower is one of these structures, which is widely used for this purpose. The main drawback of a 4-legged lattice tower is its larger base width, which occupy very large area. Nowadays, in many countries, adequate land is not available to consider such large land occupying towers. In these situations, using monopoles became common practice. But the monopoles are much costlier than the 4-legged lattice towers. To avoid the use of monopoles and to reduce the base width at the same time, in the present work, an approach has been adopted to use a special lattice type structure with eight legs. A 220 kV multi-circuit suspension tower with 0°–2° deviation has been considered for present study. The detail explanations, like, tower geometry, load calculations, analysis and design of the proposed structure has been covered in the paper. It has been observed that land requirement can be considerably minimized by use of the proposed 8-legged tower. The cost of the 8-legged tower is slightly more than a 4-legged tower but much lesser than that of monopoles as the total weight of steel required is very less as compared to monopole. The results obtained from the study of the proposed tower have been compared with 4-legged tower and monopole. This paper discusses the feasibility of using the transmission line tower with 8-legs. The paper also discusses a comparative study of cost, right of way, height and base width of 4-legged tower, monopole and proposed 8-legged tower .

Dielectric and Optical Study of Polymer Nematic Liquid Crystal Composite

Manohar, S.,Shukla, S.N.,Chandel, V.S.,Shukla, J.P.,Manohar, R. The Korean Institute of Electrical and Electronic 2013 Transactions on Electrical and Electronic Material Vol.14 No.3

The dielectric anisotropy and dispersion of the real and imaginary part of the permittivity of commercially important nematic mixture E-24 and its polymer composite were investigated in the frequency range from 1 kHz to 10 MHz, and temperature range $14^{\circ}C$ to $55^{\circ}C$. The percentage optical transmittance and density have also been measured for both the systems. The results have been explained by assuming molecular rotation about the long molecular axis, under a hindering nematic potential. The dielectric anisotropy ${\Delta}{\varepsilon}$ is positive, and the mean dielectric permittivity falls with rising temperature. ${\Delta}{\varepsilon}$ is also used to determine the order parameter with varying temperature.

Relative Microalgal Concentration in Prydz Bay, East Antarctica during Late Austral Summer, 2006

Mohan, Rahul,Shukla, Sunil Kumar,Anilkumar, N.,Sudhakar, M.,Prakash, Satya,Ramesh, R. The Korean Society of Phycology 2009 ALGAE Vol.24 No.3

Microalgae using a submersible fluorescence probe in water column (up to 100 m) were measured during the austral summer of 2006 (February) in Prydz Bay, East Antarctica (triangular-shaped embayment in the Indian sector of Southern Ocean). Concurrently, environmental parameters such as temperature, salinity and nitrogen (nitrate, ammonium, urea) uptake rates were measured. The concentration of phytoplankton is relatively high due to availability of high nutrients and low sea surface temperature. Phytoplankton community is dominated by diatoms whereas cryptophytes are in low concentration. The maximum concentration of total chlorophyll is 14.87 ${\mu}g\;L^{-1}$ and is attributed to upwelled subsurface winter water due to local wind forcing, availability of micro-nutrients and increased attenuation of photosynthetically available radiation (PAR). Concentration of blue-green algae is low compared to that of green algae because of low temperature. Comparatively high concentration of yellow substances is due to the influence of Antarctic melt-water whereas cryptophytes are low due to high salinity and mixed water column. Varied concentrations of phytoplankton at different times of Fluoroprobe measurements suggest that the coastal waters of Prydz Bay are influenced by changing sub-surface water temperature and salinity due to subsurface upwelling induced by local winds as also melting/freezing processes in late summer. The productivity is high in coastal water due to the input of macro as well as micro-nutrients.

Design and Analysis of Microstrip Bandpass Filter with Half-Wave Length Open Circuited Stubs

Satya Bhushan Shukla,R.N. Baral,P.K. Singhal 대한전자공학회 2006 ITC-CSCC :International Technical Conference on Ci Vol.2006 No.3

ZnO/FLC nanocomposites with low driving voltage and non-volatile memory for information storage applications

A. Chaudhary,R.K. Shukla,P. Malik,R. Mehra,K.K. Raina 한국물리학회 2019 Current Applied Physics Vol.19 No.12

Nanocomposites comprises of nano sized zinc oxide (ZnO, size ~10 nm) particles and ferroelectric liquid crystal (FLC) material have been prepared and studied. The concentration of the dopant (ZnO nanoparticles) in FLC matrix varied from 0.0 to 1 wt%. Distinct nanocomposites have been used to fabricate memory device and studied through dielectric spectroscopy, optical microscopy and electro-optical methods to explore electro-optic and memory parameters. Experimental results reveal that doping of ZnO nanoparticles in FLC leads to long lasting memory and low deriving voltage in nanocomposites. The achieved prolonged memory effect in nanocomposites may attribute to the charge transfer at the interfaces. Another reason, application of applied field may lead to ion trapping effect at ZnO surface which in turn minimize the depolarized field and enhance the memory effect in nanocomposites.

Association between p53 Gene Variants and Oral Cancer Susceptibility in Population from Gujarat, West India

Patel, Kinjal R.,Vajaria, Bhairavi N.,Begum, Rasheedunnisa,Shah, Franky D.,Patel, Jayendra B.,Shukla, Shilin N.,Patel, Prabhudas S. Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Background: p53 gene variants i.e. 16 bp duplication in intron 3, Arg72Pro in exon 4 and G>A in intron 6 have been reported to modulate susceptibility to various malignancies. Therefore, the present study evaluated the role of these p53 polymorphisms in oral cancer susceptibility in a population from Gujarat, West India. Method: Genotype frequencies at the three p53 loci in 110 controls and 79 oral cancer cases were determined by the PCR-RFLP method. Results: Heterozygous individuals at exon 4 showed protection from developing oral cancer. Homozygous wild and heterozygous individuals at intron 3 and those heterozygous at exon 4 in combination appeared to be at lowered risk. Furthermore, carriers of the 16 bp duplication allele at intron 3, proline allele at exon 4 and G allele at intron 6 were protected from oral cancer development. Conclusion: p53 polymorphisms, especially Arg72Pro in exon 4 could significantly modify the risk of oral cancer development in Gujarat, West Indian population.