Pathogenicity and Polyhedra Morphology of Spilarctia obliqua Nucleopolyhedrosis Virus

(Vineet Kumar),(V. P. Gupta),(A. Sarkar),(A. M. Babu),(R. K. Datta) 한국잠사학회 2000 International Journal of Industrial Entomology Vol.1 No.2

Gravimetrics of Pupal Weight Loss in the Domestic Silkworm, Bombyx mori Linn. (Lepidoptera : Bombycidae)

Kumar, Vineet,Kariappa, B.K.,Chaturvedi, H.K.,Sarkar, A.,Datta, R.K. Korean Society of Sericultural Science 2000 International Journal of Industrial Entomology Vol.1 No.1

A comprehensive study on daily pupal weight loss due to histolysis and histgenesis in Bombyx mori Linn., has been undertaken. The percentag of pupal weight loss in the male pupa is higher than the female, conforming that the female pupa require more energy in the form of less pupal weight loss for ovipositional activities. The regression equation clearly shows higher percentage loss of daily pupal weight in male than female with respect to age and, this is also evident from the slope of the regression line. Moreover, analysis of the coefficient of correlation shows that the weight loss of pupa is directly correlated with the age rather than climatic parameters under which the pupa dwells.

Radial junction silicon solar cells with micro-pillar array and planar electrode interface for improved photon management and carrier extraction

Vineet Kumar Singh,Jampana Nagaraju,Sushobhan Avasthi 한국물리학회 2019 Current Applied Physics Vol.19 No.3

We demonstrate radial p-n junction silicon solar cells with micro-pillar array with higher short-circuit current and open-circuit voltage than comparable planar silicon solar cells. Micro-pillar array, fabricated by RIE, acts as an effective anti-reflection coating for visible light with less than 6% reflection. Compared to devices with planar surface, devices with micro-pillar array show a 27% enhancement in short circuit current. The radial p-n junction of the micro-pillars also improves extraction probability of the photogenerated carriers, which further increases the short circuit current. Typically, micro-pillar solar cells suffer from high recombination losses at the Si/metal interface, resulting in poor VOC. Our devices prevent these recombination losses by planarizing the Si/ metal interface, leading to an open circuit voltage of 622 mV, the highest ever reported for micro-pillar solar cells. This planarized contact also reduces the series resistance associated with radial junctions, leading to series resistance of ≤0.50 Ω-cm2 and fill factors up to 76.7%.

Conductive films of sonicated multiwall carbon nanotubes on stretchable substrates

Kumar, Vineet,Wu, Rui‐,Rui,Zhen, Qi‐,Ye,Lee, Dong‐,Joo John Wiley Sons, Ltd 2018 Polymer international Vol.67 No.11

<P><B>Abstract</B></P><P>Conductive films were prepared on stretchable substrates by mixing sonicated multiwall carbon nanotubes (MWCNTs) with room‐temperature‐vulcanized silicone rubber. Microscopic investigations show a broad range of MWCNT particles with diameters in the range 15–17 nm, lengths from a few nanometers to a few micrometers, and thus a high aspect ratio of 55–70. The sonicated MWCNTs have 40 wrapped graphene layers and an out‐of‐plane correlation length of 13 nm. Also, the grain size of the dispersed sonicated MWCNTs is around 35 nm, and the roughness is around 13.5 nm. At 3 phr, the modulus is higher for the MWCNTs (5.95 MPa). The electrical resistance of the MWCNTs is as low as 180 Ω at 3 phr. These improvements were introduced in an actuator and energy harvester for industrial applications. The actuator shows a displacement of 2.18 mm at 10 kV. At 60% strain, the energy harvesting is 1.07 V during compressive strain and 0.015 V during tensile strain. From durability tests under 30% compressive strain, the voltage drops from the energy harvesting device are negligible for up to 3000 cycles. © 2018 Society of Chemical Industry</P>

The response force and rate of magneto-rheological elastomers with different fillers and magnetic fields

Kumar, Vineet,Lee, Jin-Yong,Lee, Dong-Joo Elsevier 2018 Journal of magnetism and magnetic materials Vol.466 No.-

<P><B>Abstract</B></P> <P>This study looks at the response rate and magnitude of magneto-rheological elastomers (MREs) upon applying magnetic field depending on the type and content of iron powder. Specimens were prepared under different magnitudes of an applied magnetic field during vulcanization. S1640 (carbonyl) iron powder has a round shape and small size (3–5 µm), and Fe#400 (electrolytic) has irregular shape and large size (6–11 µm). Both of these were used at up to 80 phr. In general, the specimen with S1640 has a better response force and more rapid response to an external magnetic field than the specimen with Fe#400. However, the compressive characteristics of the Fe#400 specimen with low iron powder content (40 phr) and isotropic conditions are better than those of the S1640 specimen. The experimental results show better mechanical properties and rapid response with an applied magnetic field of 1.5 T compared to 2.0 T during the specimen vulcanization. This means that the smaller iron powder can move faster when applying the magnetic field than the bigger iron powder, and the iron powder distribution influences the compressive modulus and response behaviors. Therefore, the response and force to an applied magnetic field and the durability of the MRE are better with the S1640 iron powder, and the pattern is similar to the compressive modulus.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The specimen with S1640 has a better response force and more rapid response to an external magnetic field of 90 mT than the specimen with Fe#400. </LI> <LI> The on/off switching test with a constant magnetic field (90 mT) showed that the response rate becomes faster with the number of on/off cycles. </LI> <LI> The specimen with better mechanical properties shows a rapid response rate and large response force upon applying a magnetic field during the stress relaxation test after applying 10 and 20% strain. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

SEM Observations on the Perithecia of Phyllactinia corylea Causing Powdery Mildew Disease in Mulberry

Kumar, Vineet,Dhar, Anil,Gupta, V.P.,Babu, A.M.,Sarkar, A.,Datta, R.K. Korean Society of Sericultural Science 2001 International Journal of Industrial Entomology Vol.3 No.1

Surface morphology of perithecia of the powdery mildew fungus of mulberry, Phyllactinia corylea is described under scanning electron microscope. The perithecia have penicellate cells on the upper surface and at an average 17 acicular appendages towards the lower surface each emerging from a bulbous base. Many perithecial walls towards the base have shrunken walls. When the perithecia dry out they are pushed above the leaf surface by the acicular append-ages which then bend at the base. The bending of the appendages may be attributed to the shrinkage of lower wall cells due to loss of water.

Effect of Indium Doping and Annealing on Photoconducting Property of Wurtzite Type CdS

Vineet Kumar Singh,Pratima Chauhan,Sheo Kumar Mishra,Rajneesh K Srivastava 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.3

In this paper we observed the effect of doping and annealing on the dark current and anomalous photoconducting behavior of hexagonal wurtzite CdS, synthesized by solid state reaction method. Undoped CdS sample shows higher anomalous behavior in photoconductivity as well as contains larger dark current of 19 nA. With the doping of Indium in CdS, dark current decreases from 19 nA to 1 nA but the anomalous behavior is not completely removed. While, after annealing at 150°C for four hour, indium doped CdS sample shows good switching property with rise and decay time of 360 ± 10 & 322 ± 6 seconds respectively. The anomalous photoconducting behavior is completely removed from annealed sample. X-ray diffraction patterns confirm the existence of hexagonal wurtzite phase of indium doped and undoped CdS samples while energy dispersion X-ray spectrum exhibits the elemental presence of cadmium, indium & sulfur in the indium doped sample. UV-Visible absorption spectra show the blue shift in absorption edge on indium doping from 475 nm to 425 nm in comparison to undoped sample. Photoluminescence spectra confirm the indium doping and reveal that annealed CdS sample has lesser defects among other samples due to which annealed sample has best switching performance.

Pathogenicity and Polyhedra Morphology of Spilarctia obliqua Nucleopolyhedrosis Virus

Kumar, Vineet,Gupta, V.P.,Sarkar, A.,Babu, A.M.,Datta, R.K. Korean Society of Sericultural Science 2000 International Journal of Industrial Entomology Vol.1 No.2

Spilarctia obliqua(Wlk.) is a serious pest of mulberry which is naturally affected by its nucleopolyhedrosis virus (SoNPV) in field conditions. The polyhedral occlusion bodies (POB's) were hexahedron under scanning and transmission electron microscope and measured 0.42${\mu}{\textrm}{m}$ to 0.67 ${\mu}{\textrm}{m}$ in diameter. The symptoms of NPV infected S. obliqua larvae resembled with that of other NPVs' infected lepidopterous larvae. The pathogenicity and potentiality of this virus against S. obliqua was tested in the laboratory conditions and the results showed 100% mortality in larvae inoculated with SoNPV at 6.23${\times}10^5$ POBs/ml. Therefore, SoNPV appears to have a high potential as a microbial biocontrol agent against S. obliqua larvae.

Synergistic effects of hybrid carbon nanomaterials in room‐temperature‐vulcanized silicone rubber

Kumar, Vineet,Lee, Jin‐,Yong,Lee, Dong‐,Joo Published for SCI by Elsevier Applied Science 2017 Polymer international Vol.66 No.3

<P><B>Abstract</B></P><P>This work examines nanocomposites based on nanofillers and room‐temperature‐vulcanized silicone rubber. The carbon nanofillers used were conductive carbon black (CB), carbon nanotubes (CNTs) and graphene (GE). Vulcanizates for CB, GE, CNTs as the only filler and hybrid fillers using CNTs, CB and GE were prepared by solution mixing. The elastic modulus for CNT hybrid with CB at 15 phr (4.65 MPa) was higher than for CB hybrid with GE (3.13 MPa) and CNTs/CB/GE as the only filler. Similarly, the resistance for CNT hybrid with CB at 10 phr (0.41 kΩ) was lower than for CB (0.84 kΩ) at 20 phr and CNTs as the only filler. These improvements result from efficient filler networking, a synergistic effect among the carbon nanomaterials, the high aspect ratio of CNTs and the improved filler dispersion in the rubber matrix. © 2016 Society of Chemical Industry</P>

Studies on the Biology and Predatory Behaviour of Eocanthecona furcellata (Wolff.) Predating on Spilarctia obliqua (Walk.) in Mulberry Plantation

Kumar, Vineet,Morrison, M.N.,Rajadurai, S.,Babu, A.M.,Thiagarajan, V.,Datta, R.K. Korean Society of Sericultural Science 2001 International Journal of Industrial Entomology Vol.2 No.2

The stink bug, Eocanthecona furcellata (Wolff.) is a natural and potential biocontrol agent of Spilarctia obliqua (Walk.). The present investigation reveals the biology, predatory efficiency and reproductive parameters of the predator which feeds on S. obliqua caterpillars in mulberry plantation. In order to find out the role of prey sine on the biology of the predators the predatory insects were separately fed with small and large caterpillars of S. obliqua. The incubation period of the eggs of E. furcellata was 8.37${\pm}$0.44 days, while the nymphal duration varied as per the prey sine. The predator when supplied with small larvae of prey, consumed 61.1 larvae and completed nymphal stage in 19.9 days; while those fed with larger prey, consumed 36.1 larvae and completed their nymphal stage in 21.55 days. The prey size also influences the reproductive parameters of the predator, The adult female predator is more voracious feeder than the adult male and consumed 41.9${\pm}$0.64 small larvae and 42.2${\pm}$0.87 large larvae during their life span. The longevity of male and female was observed as 20.7 and 29.4 days respectively. Visualization of the predator as well as the movement of the prey increases the predatory efficiency. Scanning electron microscopic studies on the feeding part explain its support in effective predation. Field observations indicated a drastic fall in the incidence of the mulberry pest, S. obliqua with the increased population E. furcellata in mulberry plantation.