Incorporation of Graphitic Porous Carbon for Synthesis of Composite Carbon Aerogel with Enhanced Electrochemical Performance

Singh, Ashish,Kohli, D.K.,Singh, Rashmi,Bhartiya, Sushmita,Singh, M.K.,Karnal, A.K. The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.2

We report, synthesis of high surface area composite carbon aerogel using additive based polymerization technique by incorporating graphitic porous carbon as additive. This additive was separately prepared using sol-gel polymerization of resorcinol-furfuraldehyde in iso-propyl alcohol medium at much above the routine gelation temperature to yield porous carbon (CA-IPA) having graphitic layered morphology. CA-IPA exhibited a unique combination of meso-pore dominated surface area (~ 700 m²/g) and good conductivity of ~ 300 S/m. The composite carbon aerogel (CCA) was synthesized by traditional aqueous medium based resorcinol-formaldehyde gelation with CA-IPA as additive. The presence of CA-IPA favored enhanced meso-porosity as well as contributed to improvement in bulk conductivity. Based on the surface area characteristics, CCA-8 composition having 8% additive was found to be optimum. It showed specific surface area of ~ 2056 m²/g, mesopore area of 827 m²/g and electrical conductivity of 180 S/m. The electrode formed with CCA-8 showed improved electrochemical behavior, with specific capacitance of 148 F/g & ESR < 1 Ω, making it a better choice as super capacitor for energy storage applications.

ANION INDUCED BLUE TO PURPLE TRANSITION IN BACTERIORHODOPSIN

Singh, Anil K.,Kapil, Mrunalini M. Korean Society of Photoscience 1996 Journal of Photosciences Vol.3 No.2

Anil K. Singh, Mrunalini M. Kapil, Department of Chemistry, Indian Institute of Technology Bombay - 400076, INDIA Purple membrane (PM, $\lambda$$_{max}$ 570 nm) of H. halobium on treatment with sulphuric acid changes its colour to blue ($\lambda$$_{max}$ 608 nm). The purple chromophore can be regenerated from the blue chromophore by exogeneous addition of anions such as CI$^-$ and HPO$_4^{2-}$. Chloride ion is found to be more effective than the dibasic phosphate ion in regenerating the purple chromophore. Nevertheless, one thing common to the anion regeneration is that both CI$^-$ and HPO$_4^{2-}$ show marked pH effect. At pH 1.0 the efficiency of regeneration of the purple chromophore is greater than at pH 2.0, for the same anion concentration. Fluorescence and circular dichroic studies indicate that the proteins do not undergo drastic changes at the secondary' or tertiary structure level and the native structure is preserved during this transition. However, chromophoric-site interactions between retinal and the apoprotein are affected during this colour transition. A molecular mechanism is advanced for this transition.

Strong elevational trends in soil bacterial community composition on Mt. Halla, South Korea

Singh, D.,Lee-Cruz, L.,Kim, W.S.,Kerfahi, D.,Chun, J.H.,Adams, J.M. Pergamon Press ; Elsevier Science Ltd 2014 Soil biology & biochemistry Vol.68 No.-

Elevational trends in the ecology of macroorganisms have been studied extensively; by contrast very little is known of such trends in microbial diversity. Previous studies on soil bacteria have found either a diversity decline, a 'peak' in mid altitudes, or no trend with increasing elevation. Here we studied bacterial diversity and community composition in relation to elevation on Mt. Halla, Jeju Island, South Korea, a massive shield volcano. Samples were taken along two transects, from 100 m.a.s.l. to the summit at 1950 m.a.s.l., at elevational intervals of 200 m. PCR-amplified soil DNA for the bacterial 16S rRNA gene targeting V1 to V3 region was 454-pyrosequenced, and taxonomically classified against EzTaxon-e database. Elevation was the best predictor of variation in bacterial community composition along the two transects, even when considering other soil parameters. Elevation was itself highly correlated with mean annual temperature (MAT) and mean annual precipitation (MAP), suggesting that soil bacterial community composition on Mt. Halla is more strongly affected by climate than by geochemical or soil textural factors. The two transects showed certain consistent differences in bacterial phyla composition, with one transect having significantly higher abundance of Planctomycetes and Gemmatimonadetes than the other. Certain other phyla (e.g. Acidobacteria) also showed striking trends in abundance with elevation, but the trends differed between the two transects. Bacterial diversity and richness were also most strongly correlated with elevation, MAT and MAP, although soil pH explained a part of the variation. Moreover, vegetation cover type, irrespective of elevation, had an effect on soil bacterial diversity and richness. We found a 'dip' in diversity at lower mid elevations (700-1300 m) in both transects; a trend which has not been found before. Our results, when compared with other studies, emphasize that no simple rule can be applied to mountain systems in general, but that climate itself is a major influence on community composition.

A hump-backed trend in bacterial diversity with elevation on Mount Fuji, Japan.

Singh, Dharmesh,Takahashi, Koichi,Kim, Mincheol,Chun, Jongsik,Adams, Jonathan M Springer-Verlag 2012 Microbial ecology Vol.63 No.2

<P>Little is known of how bacterial diversity in soils varies with elevation. One previous study found a decline with elevation, whereas another found no trend. We chose Mount Fuji of Japan as a geologically and topographically simple mountain system. Samples were taken at elevational intervals, between the base of the mountain at 1,000 m and its summit at 3,700 m. Polymerase chain reaction-amplified soil DNA for the bacterial 16S gene targeting V1-V3 region was pyrosequenced using the 454 Roche machine, and taxonomically classified with reference to a bioinformatic database. There was a significant 'peak' in total bacterial diversity at around 2,500 m above the tree line with a decline towards the highest elevations around 3,700 m near the summit. Individual bacterial phyla show distinct trends-increase, decrease, or a mid-elevational 'bulge' in diversity. Bacterial diversity does not parallel woody plant or herbaceous plant diversity. We suggest that beyond the tree and vegetation line, the more extreme temperature fluctuations, stronger UV, lack of nutrients, and more frequent disturbance of the loose substrate of these slopes allows less competition and greater bacterial species diversity due to 'lottery' recruitment. However, at the highest elevations, the physiological challenges are so extreme that fewer bacterial species are capable of surviving.</P>

Biotoxic Cyanobacterial Metabolites Exhibiting Pesticidal and Mosquito Larvicidal Activities

( Singh Dhananjaya P. ),( Ashok Kumar ),( M. B. Tyagi ) 한국미생물생명공학회 2003 Journal of microbiology and biotechnology Vol.13 No.1

Tree species richness, diversity, and regeneration status in different oak (Quercus spp.) dominated forests of Garhwal Himalaya, India

sushma singh,Zubair A. Malik,Chandra M. Sharma 국립중앙과학관 2016 Journal of Asia-Pacific Biodiversity Vol.9 No.3

Himalayan forests are dominated by different species of oaks (Quercus spp.) at different altitudes. These oaks are intimately linked with hill agriculture as they protect soil fertility, watershed, and local biodiversity. They also play an important role in maintaining ecosystem stability. This work was carried out to study the diversity and regeneration status of some oak forests in Garhwal Himalaya, India. A total of 18 tree species belonging to 16 genera and 12 families were reported from the study area. Species richness varied for trees (4–7), saplings (3–10), and seedlings (2–6). Seedling and sapling densities (Ind/ha) varied between 1,376 Ind/ha and 9,600 Ind/ha and 167 Ind/ha and 1,296 Ind/ha, respectively. Species diversity varied from 1.27 to 1.86 (trees), from 0.93 to 3.18 (saplings), and from 0.68 to 2.26 (seedlings). Total basal area (m2/ha) of trees and saplings was 2.2–87.07 m2/ha and 0.20–2.24 m2/ha, respectively, whereas that of seedlings varied from 299 cm2/ha to 8,177 cm2/ha. Maximum tree species (20–80%) had “good” regeneration. Quercus floribunda, the dominant tree species in the study area, showed “poor” regeneration, which is a matter of concern, and therefore, proper management and conservation strategies need to be developed for maintenance and sustainability of this oak species along with other tree species that show poor or no regeneration.

A family of hypergeometric integrals associated with Ramanujan's integral formula

H. M. Srivastava,M. I. Qureshi,R. Singh,A. Arora 장전수학회 2009 Advanced Studies in Contemporary Mathematics Vol.18 No.2

The main object of this paper is to investigate some interesting applications and generalizations of Ramanujan’s integral formula (which he obtained with the help of the celebrated Ramanujan Master Theorem). Motivated essentially by some recent works by M. Garg and S. Mittal (see, for example, [South East Asian J. Math. Math. Sci. 1 (2) (2003), 85–95]), we evaluate several general families of definite integrals involving functions of one and more complex variables, some of which are then applied to derive the corresponding results associated with the generalized hypergeometric function pFq and the Fox-Wright further generalizations denoted by p[수식]q and p[수식]q . An integral formula considered recently by R. P. Agarwal [Resonance of Ramanujan’s Mathematics, Vol. I, New Age International Publishers Limited, New Delhi, 1996], which is closely associated with the aforementioned Ramanujan’s result, is also corrected and modified here appropriately.

Synthesis, magnetic and Mossbauer spectroscopic studies of Cr doped lithium ferrite nanoparticles

Srivastava, M.,Layek, S.,Singh, J.,Das, A.K.,Verma, H.C.,Ojha, A.K.,Kim, N.H.,Lee, J.H. Elsevier Sequoia 2014 JOURNAL OF ALLOYS AND COMPOUNDS Vol.591 No.-

Lithium-based ferrites are promising and potential magnetic materials for microwave applications. They possess a spinel (AB<SUB>2</SUB>O<SUB>4</SUB>) type crystal structure, where the distributions of metal cations over the tetrahedral (A) and octahedral (B) voids play a crucial role for exhibiting different physical properties. Among various parameter of synthesis, pH is an important factor that influences the cation distribution over A and B voids, overall growth of the nanoparticles and different physical properties. In the present work single phase Cr substituted lithium ferrite nanoparticles have been synthesized by the sol-gel method at different pH. The phase identification and crystallite size have been probed by X-ray diffraction studies. The crystallite size changes by 44.2-48.8nm upon varying the pH from 3.5 to 11.5. In order to investigate the cations distribution at A/B sites, Mossbauer spectroscopic measurements were done. The values of magnetic hyperfine field obtained from the Mossbauer data for the A and B sites are ~49.5T and 51T, respectively. Moreover, it is observed that the area ratio of B site to A site increases with increasing the pH. This observation further suggests that the B site is more preferable for Fe<SUP>3+</SUP> cations at higher pH than the A site. The magnetic parameter such as saturation magnetization (M<SUB>s</SUB>), remanent magnetization (M<SUB>r</SUB>), coercive field (H<SUB>C</SUB>) and squareness (S) are determined by vibrating sample magnetometer (VSM) measurements, which show a consistent increase with increasing pH. The reason for the variation in magnetic properties has been explained on the basis of increased Fe<SUP>3+</SUP> cation occupancies at the B site and size effect, which is well supported by Mossbauer spectroscopic and XRD studies.

Production of nematode free plantlets in Polianthes tuberosa using in vitro culture techniques

Kanchan B. M. Singh,Jayanthi Madhavan,Raghunath Sadhukhan,Shivani Chandra,Uma Rao,Pranab Kumar Mandal 한국원예학회 2020 Horticulture, Environment, and Biotechnology Vol.61 No.5

Tuberose ( Polianthes tuberosa ) cultivation is tremendously aff ected due to Meloidogyne incognita infection. Histologicalstudy of in vitro nematode infected tuberose roots showed that the root infection initiated within 2 days post inoculation(DPI) and root gall formation occurred at 6 DPI indicating established infection on the roots. The life cycle of M. incognitain tuberose roots completed within 45 DPI evident by the formation of large number of eggs. Our study established in vitromethods like shoot tip culture and callus mediated regeneration of tubers collected from nematode infection fi elds to obtaincompletely nematode free plantlets. Tubers of diff erent varieties produced multiple shoot bud on Murashige and Skoog (MS)media containing 4 mg L −1 6-benzylaminopurine (BAP) and 0.1 mg L −1 α-naphthaleneacetic acid (NAA). Maximum numbersof plantlets were obtained for Calcutta Single (14.4 ± 2.0 per plant). Embryogenic callus was induced on MS medium supplementedwith altered concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D), NAA and BAP from leaf, fl ower, root andtuber explant. The maximum callus induction was obtained on MS containing 1 mg L −1 2,4-D, 1 mg L −1 NAA and 0.5 mg L −1BAP (100%) and 1 mg L −1 2,4-D and 2.25 mg L −1 BAP (96.7%). Regeneration of tuber callus was achieved on MS with0.5 mg L −1 Kinetin (KIN) within 3 weeks. Plantlets were rooted on ½ MS with 0.5 mg L −1 Indole-3-butyric acid for 25 days. The in vitro regeneration protocol developed can thus be used for producing disease free plantlets for mass propagation.

Tribological and characterization studies of aluminium alloy 6061 reinforcement with aluminium oxide and copper metal matrix composites

D. Elil Raja,S. Prathap Singh,V. Rangarajan,M. Chrispin Das 한양대학교 청정에너지연구소 2022 Journal of Ceramic Processing Research Vol.23 No.6

Ultrasonic assisted stir casting was used to fabricate aluminium based metal matrix composite reinforcement with 4% copperand various combinations (0, 1 or 2 wt.%) of aluminium oxide. In this study, Taguchi Grey Relational Analysis (GRA) wasused to optimise the wear behaviour of the metal matrix composite reinforcement. Reinforcing elements were visualised usingSEM, which shows that a uniform distribution is possible with just 1% aluminium oxide additions. In order to betterunderstand the association between wear factors such as sliding distance, sliding speed and applied load, we looked at the wearrate and friction coefficient. According to the Taguchi L9 orthogonal array, we conducted the trials. In each experiment, therate of wear as well as the coefficient of friction were measured. If you apply a force of 10 N, slide at 1 m/s for 1500 metres,the Taguchi GRA concluded that this was the best combination for your experiment. There is a 61 percent correlation betweenthe sliding velocity and composite wear. After all was said and done, the most well-worn surface was found to have the fewestscratches and fine grooves.