25 research outputs found

    Ascorbic acid Beta-Carotene and Amino acids in Capsicum (Capsicum annuum) during fruit development in Himalayan Hills

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    Capsicum varieties viz HC-201 & HC-202 developed at ARU, Almora took 35 days from fruit set to ripening. Results showed significant positive correlation for ascorbic acid and Beta-carotene with days to maturity. Out of eight ninhydrin positive products, only seven could be identified viz, hydroxyproline, proline, lysine, 5-alanine, arginine, threonine and methionine, at the later stages of the fruit development. All amino acids except methionine were found either absent or in traces at the earlier stages of fruit development

    Effect of ice crystal size and graupel velocity on thundercloud electrification

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    313-319A one-dimensional time dependent model for cloud electrification, which includes collision between ice crystal and graupel in the presence of cloud liquid water, has been developed in order to test the importance of various charge transfer parameters. The laboratory measurements .showed that the charge transfer depends on ice crystal size and impact velocity. The generated electric fields have been calculated for various values of size dependency (a), velocity dependency (b), precipitation intensity (p0), concentration of ice crystals (n) and event probability (p).lt is found that the estimated electric field (4 x 105 Vm-1), within a time interval of about 1500 s, can be achieved for p0≥ 30 mmh-1. The maximum electric field (Emax) is not sensitive to the values of a and b, but its rate of growth is faster if a and b are larger. The obtained results have been discussed in the light of various experimental observations and it has been found that charging rates may be affected by the specified size and velocity dependencies

    Electric Field at the Ground Due to a Thundercloud of Finite Dimensions

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    Variation in Ground Electric Field due to Various Forms of Intracloud Lightning Discharges

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    104-109The calculations for instantaneous and total changes in ground electric field due to various forms of intracloud lightning discharges are presented. To place in perspective the significance of the individual form of intra cloud discharge, three possible cases, namely, propagation of positive, negative and complex streamers have been studied separately. The important aspects of thunderclouds such as spatially inhomogeneous charge distribution, redistribution of charge due to propagation of streamers, and concept of finite dimensions of streamers and thunderclouds have been taken into account. The present study points out the incapability of the electric field variation dependent hypothesis to distinguish between a negative and a complex streamer because both these streamers produce negative changes in ground electric field. Our theoretical findings suggest that a more convincing hypothesis to classify the nature of intracloud discharges should incorporate magnitudes of electric field variations along with the nature of electric field changes. Plots of total electric field change against distance of observing point show a reasonable agreement with the observed magnitude variations and electric field sign reversal distances at ground

    Multifunctional behaviour of nanostructured Pb0.7Sr0.3(Fe0.012Ti0.988)O3 thin film

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    Structural, magnetic, electrical and optical properties of the Pb0.7Sr0.3(Fe0.012Ti0.988)O3 (PSFT) thin film have been studied. The PSFT solution was prepared by the sol–gel combined metallo-organic decomposition method and deposited on Si, Pt/Ti/SiO2/Si and fused quartz substrates by the spin-coating technique. The superparamagnetic relaxation between bulk nanoparticles and film nanograins has been done. The insulating gaps between the PSFT nanograins made symmetrically coupled plasmon modes and explored their potential in magneto-optic data storage, light generation, microscopy and bio-photonics

    Dielectric properties of nanocrystalline Pb0.8Sr0.2TiO3 thin films at different annealing temperature

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    Nanocrystalline Pb0.8Sr0.2TiO3 (PST20) thin films have been synthesized by metallo-organic decomposition (MOD) technique and deposited on Pt/Ti/SiO2/Si substrates at different annealing temperatures of 550–750 °C. The X-ray diffraction (XRD) confirms the distorted tetragonal perovskite phase in PST20 films. The average grain's size varies from 35 nm to 46 nm as the annealing temperature increases from 650 °C to 750 °C as revealed by atomic force microscopy. At 550 °C, the film shows low crystallization with incomplete perovskite structure. The study of dielectric properties of PST20 films is aimed at electrically tunable applications and to observe ferroelectric behaviors of PST20 films. The film annealed at 650 °C shows large dielectric constant and higher tunability than the films annealed at 550 °C and 750 °C. The values of dielectric constant and tan δ at 1 MHz are 272 and 0.005, respectively, and tunability is ∼66% for PST20 film annealed at 650 °C. The dispersionless dielectric properties are observed up to high frequency ∼8 MHz. The results suggest that the growth of uniform, dense and nano-sized grains in PST film makes it suitable for higher frequency device applications and electrically tunable devices

    Magnetic and electrical properties of manganese and cadmium co-substituted lithium ferrites

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    Manganese and cadmium co-substituted lithium ferrite having the general formulae Li0.35Cd0.3MnxFe2.35−xO4 + 0.10 wt% Bi2O3 with x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 has been prepared by standard ceramic technique. M–H curves of all samples have been determined by using vibrating sample magnetometer (VSM). The highest saturation magnetization 79 emu/g is observed in Li0.35Cd0.3Fe2.35O4 (Mn = 0) and it decreases with increase in manganese content in the compound. It is observed that the value of initial permeability increases to maximum value ∼230 for Mn = 0.4 and then decreases with further increase in Mn contents. The dc resistivity of all samples is found in the range of 107 Ω cm

    Study of Humidity Sensing Property of LiCe Substituted Magnesium Ferrite

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    A drop in electrical resistance with relative humidity of LiCe substituted magnesium ferrite series has been investigated. The drop in resistance is 2 to 2.6 order of magnitude for the range 20-80% RH for different compositions. The LiCe substitution in magnesium ferrite decreased the grain size and the pore size distribution of magnesium ferrite increased as evident by SEM micrographs. The bulk porosity is increased with LiCe substitution calculated by linear intercept method. The adsorption humidity response time is within 180 s recorded for a step change of 40% RH for different samples. The humidity hysteresis curves are plotted for all the samples, an area enclosed is with in 1%-6% RH. In Raman spectra five characteristics spinel peaks along with small peaks observed for different compositions
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