X-RAY ASTRONOMY EXPERIMENT ON THE INDIAN SATELLITE IRS-P3

AGRAWAL P. C.,PAUL B.,RAO A. R.,SHAH M. R.,MCKERJEE K.,VARIA M. N.,YADAV J. S.,DEDHIA D. K.,MALKAR J. P.,SHAH P.,DAMLE S. V.,MARAR T. M. K.,SEETHA S. The Korean Astronomical Society 1996 Journal of The Korean Astronomical Society Vol.29 No.suppl1

An x-ray astronomy experiment consisting of three collimated proportional counters and an X-ray Sky Monitor (XSM) was flown aboard the Indian Satellite IRS-P3 launched on March 21, 1996 from SHAR range in India. The Satellite is in a circular orbit of 830 km altitude with an orbital inclination of $98^{\circ}$ and has three axis stabilized pointing capability. Each pointed-mode Proportional Counter (PPC) is a multilayer, multianode unit filled with P-10 gas ($90\%$ Ar + $10\%\;CH_4$) at 800 torr and having an aluminized mylar window of 25 micron thickness. The three PPCs are identical and have a field of view of $2^{\circ}{\times}2^{\circ}$ defined by silver coated aluminium honeycomb collimators. The total effective area of the three PPCs is about 1200 $cm^2$. The PPCs are sensitive in 2-20 keV band. The XSM consists of a pin-hole of 1 $cm^2$ area placed 16 cm above the anode plane of a 32 cm$\times$32 cm position sensitive proportional counter sensitive in 3-8 keV interval. The position of the x-ray events is determined by charge division technique using nichrome wires as anodes. The principal objective of this experiment is to carry out timing studies of x-ray pulsars, x-ray binaries and other rapidly varying x-ray sources. The XSM will be used to detect transient x-ray sources and monitor intensity of bright x-ray binaries. Observations of black-hole binary Cyg X-1 and few other binary sources were carried out in early May and July-August 1996 period. Details of the x-ray detector characteristics are presented and preliminary results from the observations are discussed.

A Study of the<i>Kepler K2</i>Variable EPIC 211957146 Exhibiting a Variable O’ Connell Effect

Sriram, K.,Malu, S.,Choi, C. S.,Rao, P. Vivekananda American Astronomical Society 2017 The Astronomical journal Vol.153 No.5

<P>We present the multi-band photometric and spectroscopic study of an over-contact binary system, EPIC 211957146. The light curves exhibit a variable O' Connell effect, confirmed from our observational data and the Kepler K2 data. The best photometric solution incorporating a dark spot over the primary component unveils that the system has a low-mass ratio (q similar to 0.17) and a high inclination (i similar to 85 degrees). To confirm the solution and constrain the uncertainty, Monte-Carlo simulations are performed and the results are reported. Based on the O-C diagram analysis, we see that the variable shows a period increase at the rate of dP/dt similar to 1.06. x. 10(-6) days yr(-1), which is higher than the theoretically predicted value. Presence of a third body having a period of similar to 16.23 years is evident from the O-C diagram. No filled-in effect is observed in the Ha line, while the effect is vividly present in the Na line. From the Kepler K2 data, we found that the primary and secondary minima exhibit an anti-correlated O-C variation followed by an erratic behavior. This is possibly caused by the longitudinal motion of the spot, and hence, we set a lower limit of similar to 40 days for the spot modulation. We also observe a possibly associated photometric difference in the primary depth by comparing our light curves with Kepler K2 normalized light curves. This system has a low-mass ratio and a high fill-out factor, and, theoretically, such a physical configuration would lead to a merger.</P>

ASAS J083241+2332.4: A NEW EXTREME LOW MASS RATIO OVERCONTACT BINARY SYSTEM

Sriram, K.,Malu, S.,Choi, C. S.,Vivekananda Rao, P. American Astronomical Society 2016 The Astronomical journal Vol.151 No.3

<P>We present the R-and V-band CCD photometry and H alpha line studies of an overcontact binary ASAS J083241+2332.4. The light curves exhibit totality along with a trace of the O'Connell effect. The photometric solution indicates that this system falls into the category of extreme low-mass ratio overcontact binaries with a mass ratio, q similar to 0.06. Although a trace of the O' Connell effect is observed, constancy of the H alpha line along various phases suggest that a relatively higher magnetic activity is needed for it to show a prominent fill-in effect. The study of O-C variations reveals that the period of the binary shows a secular increase at the rate of dP/dt similar to 0.0765 s years(-1), which is superimposed by a low, but significant, sinusoidal modulation with a period of similar to 8.25 years. Assuming that the sinusoidal variation is due to the presence of a third body, orbital elements have been derived. There exist three other similar systems, SX Crv, V857 Her, and E53, which have extremely low mass ratios and we conclude that ASAS J083241+2332.4 resembles SX Crv in many respects. Theoretical studies indicate that at a critical mass ratio range, q(critical) = 0.07-0.09, overcontact binaries should merge and form a fast rotating star, but it has been suggested that q(critical) can continue to fall up to 0.05 depending on the primary's mass and structure. Moreover, the obtained fill-out factors (50%-70%) indicate that mass loss is considerable and hydrodynamical simulations advocate that mass loss from L-2 is mandatory for a successful merging process. Comprehensively, the results indicate that ASAS J083241+2332.4 is at a stage of merger. The pivotal role played by the subtle nature of the derived mass ratio in forming a rapidly rotating star has been discussed.</P>

Evaluation of Polyvoltine Hybrids Based on Silk Productivity in Silkworm, Bombyx mori L.

C. G. P. Rao,Chandrashekaraiah,C. Ramesh,K. Ibrahim Basha,S. V. Seshagiri,H. Nagaraju 한국잠사학회 2004 International Journal of Industrial Entomology Vol.8 No.2

Polyvoltine silkworm breeds/hybrids play an important role in tropical sericulture. In the process of synthesizing more potential polyvoltine hybrids (polyvoltine ´ bivoltine) of superior quantity and quality, the Andhra Pradesh State Sericulture Research and Development Institute (APSSRDI) has developed 8 promising polyvoltine breeding lines (SDMG2, APM16, APM15, APM14, APM5, RM2, APM3, APM13). In order to study their hybrid vigour and performance, these breeds were crossed with 4 potential bivoltine testers (SDD1, SDD2, SDD3, APS8), and 32 different hybrid combinations were prepared and evaluated for their mid parent heterosis (MPH) and better parent heterosis (BPH) of silk productivity. Since silk is the ultimate product required for commercial purpose, based on silk productivity and its heterosis, three superior polyvoltine hybrid combinations namely RM2 ´ APS8 (24.3%), APM3 ´ APS8 (12.4%) and APM15 ´ SDD2 (10.8%) were adjudicated as potential heterotic hybrid combinations of superior silk yield and hence recommended for further large scale field trails and commercial exploitation.

Identification of Superior Polyvoltine Hybrids (polyvoltine x bivoltine), of Silkworm, Bombyx mori L.

C. G. P. Rao,Chandrashekharaiah,K. Ibrahim Basha,S. V. Seshagiri,C. Ramesh,H. Nagaraju 한국잠사학회 2004 International Journal of Industrial Entomology Vol.8 No.1

Ten promising polyvoltine mulberry silkworm strains (SDMG1, SDMG2, SDMG3, SDMG4, SDMW1, SDMW2, RMW1, RMW2, RMW3 and RMW4) that are superior in quantitative and qualitative traits have been synthesized in the polyvoltine breeding laboratory of Andhra Pradesh State Sericulture Research & Development Institute, Hindupur through systematic hybridization and appropriate selection methods. After the genotypes were found homozygous for the desired traits, they have been crossed with 3 bivoltine testers (APS8, APS4 and NB4D2) and thirty new hybrid combinations were developed for the assessment of their hybrid performance. Phenotypic expressions of economically important quantitative and qualitative traits of fist filial generation were measured and subjected for statistical analysis. Evaluation Index and Subordinate Function methods were employed for the assessment of hybrid performance since they are widely used in silkworm hybrid evaluation. Total of seven poly ´ bivoltine combinations, which ranked high in both the methods, were selected as potential combinations for further field test. These combinations also ranked significantly higher than the control hybrid (APM1 ´ APS8).

Identification of Superior Polyvoltine Hybrids (polyvoltine×bivoltine) of Silkworm, Bombyx mori L.

( C. G. P. Rao ),( Chandrashekharaiah ),( K. Ibrahim Basha ),( S. V. Seshagiri ),( C. Ramesh ),( H. Nagraraju ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.8 No.1

Ten promising polyvoltine mulberry silkworm strains (SDMGl, SDMG2, SDMG3, SDMG4, SDMWl, SDMW2, RMWl, RMW2, RMW3 and RMW4) that are superior in quantitative and qualitative traits have been synthesized in the polyvoltine breeding laboratory of Andhra Pradesh State Sericulture Research & Development Institute, Hindupur through systematic hybridization and appropriate selection methods. After the genotypes were found homozygous for the desired traits, they have been crossed with 3 bivoltine testers (APS8, APS4 and NB4D2) and thirty new hybrid combinations were developed for the assessment of their hybrid performance. Phenotypic expressions of economically important quantitative and qualitative traits of fist filial generation were measured and subjected for statistical analysis. Evaluation Index and Subordinate Function methods were employed for the assessment of hybrid performance since they are widely used in silkworm hybrid evaluation. Total of seven poly×bivoltine combinations, which ranked high in both the methods, were selected as potential combinations for further field test. These combinations also ranked significantly higher than the control hybrid (APMl×APS8).

Evaluation of Polyvoltine Hybrids Based on Silk Productivity in Silkworm, Bombyx mori L.

( C. G. P. Rao ),( Chandrashekaraiah ),( C. Ramesh ),( K. Ibrahim Basha ),( S. V. Seshagiri ),( H. Nagaraju ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.8 No.2

Polyvoltine silkworm breeds/hybrids play an important role in tropical sericulture. In the process of synthesizing more potential polyvoltine hybrids (polyvoltine×bivoltine) of superior quantity and quality, the Andhra Pradesh State Sericulture Research and Development Institute (APSSRDI) has developed 8 promising polyvoltine breeding lines (SDMG2, APM16, APM15, APM14, APM5, RM2, APM3, APM13). In order to study their hybrid vigour and performance, these breeds were crossed with 4 potential bivoltine testers (SDD1, SDD2, SDD3, APS8), and 32 different hybrid combinations were prepared and evaluated for their mid parent heterosis (MPH) and better parent heterosis (BPH) of silk productivity. Since silk is the ultimate product required for commercial purpose, based on silk productivity and its heterosis, three superior polyvoltine hybrid combinations namely RM2×APS8 (24.3%), APM3×APS8 (12.4%) and APM15×SDD2 (10.8%) were adjudicated as potential heterotic hybrid combinations of superior silk yield and hence recommended for further large scale field trails and commercial exploitation.

The influence of in situ deposition techniques on PbS seeded CdS/CdSe for enhancing the photovoltaic performance of quantum dot sensitized solar cells

Punnoose, D.,Suh, S.M.,Kim, B.J.,kim, S.k.,Kumar, Ch.S.S.P.,Rao, S.S.,Thulasi-Varma, C.V.,Reddy, A.E.,Chung, S.H.,Kim, H.J. Elsevier Sequoia 2016 Journal of Electroanalytical Chemistry Vol.773 No.-

<P>The deposition techniques of quantum dots (QDs) have great influence on the photovoltaic performances of quantum dot sensitised solar cells (QDSSCs). In this study, we report CdS/CdSe sensitised TiO2 solar cells focussing on the influence of two commonly used in situ QD deposition techniques (SILAR: successive ionic layer adsorption and reaction and CBD: chemical bath deposition). In addition to this, the QDSSC performance is enhanced due to better light harvesting capability of PbS quantum dots and makes large accumulation of photo-injected electrons in the conduction band of TiO2. When compared to power conversion efficiency (PCE) of 4.58% was obtained for PbS/CBD-CdS/CBD-CdSe cells when compared to PbS/SILAR-CdS/SILAR-CdSe. With chemical bath deposition, we achieved high surface coverage of QDs, which contributes to the increase in photocurrent,open circuit voltage and fill factor. Impedance spectroscopy revealed that the PbS/CBD-CdS/CBD-CdSe reduces recombination and increases charge collection efficiency and a long electron lifetime was achieved. To associate the assembling of QDs with the performance of QDSSCs a methodical characterization of morphology, optical and electro-chemical properties and its stability has been studied. We achieved PbS seeded CBD highlighting its robust consequences for the performance of QDSSCs. (C) 2016 Elsevier B.V. All rights reserved.</P>

Camellia japonica-polysiloxane based superhydrophobic hybrid powder for the selective adsorption of metal ions from a mixture of metal ions in artificial sea water

Nagappan, S.,Park, S. S.,Tapaswi, P. K.,Rao, K. M.,Ha, C. S.,Hwang, T. S. Springer Science + Business Media 2015 Journal of porous materials Vol.22 No.1

Electrical and mechanical properties of diluted magnetic semiconductor Zn_1-xMn_xS nanocrystalline films

Sreekantha Reddy, D.,Kang, B.,Yu, S.C.,Dwarakanadha Reddy, Y.,Sharma, S.K.,Gunasekhar, K.R.,Rao, K.N.,Sreedhara Reddy, P. Elsevier 2009 Current Applied Physics Vol.9 No.2

Nanostructured Zn<SUB>1-x</SUB>Mn<SUB>x</SUB>S films (0=<x=<0.25) were deposited on glass substrates by simple resistive thermal evaporation technique. All the films were deposited at 300K in a vacuum of 2x10<SUP>-6</SUP>m bar. All the films temperature dependence of resistivity revealed semiconducting behaviour of the samples. Hot probe test revealed that all the samples exhibited n-type conductivity. The nanohardness of the films ranges from 4.7 to 9.9GPa, Young's modulus value ranging 69.7-94.2GPa.