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  • 【期刊】 Optimization of drying process for PB1121 variety of paddy

    刊名:Quality Assurance and Safety of Crops & Foods 作者:S.K. Jha ; N. Patel ; S.K. Jagan ; R.K. Pal ; C. Kaur and J.P. Sinha 年份:2012
    摘要:Rough rice is typically harvested at moisture contents ranging from 20% to 24%, and subsequently dried to approximately 12% for safe long-term storage and milling. Harvesting paddy at high moisture content normally results in high yields and less damage and prevents field losses due to dropping and shattering. Drying of grains creates moisture and temperature gradient within the kernel resulting in the development of tensile stresses at the surface and compressive stress at the interior of the rice kernel. These stresses may result in kernel fissuring and subsequent breakage during milling. Thus, drying is considered to be one of the most critical operations in post-harvest processing of paddy which has great influence on milling yield. Basmati rice possesses unique cooking, eating and digestive qualities. India accounts for more than 70% of the world basmati rice production. Among basmati, PB1121 is widely grown in India and contributes a major share of rice exports from the country. Therefore drying of PB1121 was carried out with the objective to optimize the drying variables for minimum drying time and maximum head yield. Drying was carried out in 2-passes using a cross-flow dryer. The drying experiment in thin layer was conducted as per a central composite rotatable design in response surface methodology with 3 factors (drying air temperature, tempering time and moisture reduction in first drying pass) at 5 levels. The variables chosen for the experiment were drying air temperature (40–70 °C), tempering time (60–240 min) and moisture reduction percentage (3–10%) in the first pass of drying. Optimization of drying variables was done through the use of a desirability function by combining all responses into one measurement. The desirability functions were minimum drying time, maximum brown rice yield and head rice yield. Total drying time ranged from 35 to 132 min in two stages of drying, while in continuous drying it varied from 41 to 204 min. Head rice yield ranged from 39.77 to 71.56%. Optimum conditions for drying of paddy grains were found to be temperature of 58.3 °C, 7.13% moisture reduction and 148 min tempering time. At optimized conditions, total drying time and head rice yield were calculated at 53.1 min and 54.53%, respectively.
  • 【期刊】 Firmness characteristics of mango hybrids under ambient storage

    摘要:A study was conducted to determine firmness of eight mango hybrids obtained from the crosses between Amrapali and Sensation and correlate it with TSS and peel thickness. The firmness was determined at top, middle and bottom positions of the fruit using TA + Di Texture Analyzer. The peel firmness at middle position of the hybrids varied from about 20 to 33 N on harvest day, which decreased to 5-12 N with increase in storage period. On 7th day of storage, the peel firmness became almost equal from top to bottom positions indicating the even ripening of fruit. Pulp firmness was found to vary from about 5 to 20 N of freshly harvested fruit, which reduced to 0.3-3.5 N during storage. Peel firmness of 5 N and pulp firmness of 0.3 N was found as threshold points below which the fruit may not be acceptable for consumption. [All rights reserved Elsevier].
  • 【期刊】 Fluoride toxicity effects in onion (Allium cepa L

    摘要:A pot experiment was carried out under controlled condition to investigate the accumulation, uptake and toxicity effects of fluoride (F) in onion (Allium cepa L.) grown on the soil contaminated by inorganic fluoride (NaF). Six different levels of soil contamination were used by adding 0, 100, 200, 400, 600 and 800 mg NaF kg−1 to the soil. The F concentration in shoot, bulb and root varied between 16.3 and 109.1 mg F kg−1, 15.8 and 54.3 mg F kg−1 and 18.6 and 151.6 mg F kg−1, respectively. The visible symptoms of F toxicity in terms of tip burning and death of the plant was noticed in highly contaminated soils (>400 mg NaF kg−1 soil). The phyto-toxic threshold limit (LC50) in onion shoot was found to be 55 mg F kg−1, beyond which the biomass yield decreased by 50%. It was also inferred from the study that there is a partitioning of F in onion, with more accumulation in roots and shoots than in bulbs. The order of retention of fluoride in onion found to be roots > shoot > bulb.
  • 【期刊】 ZnO nanorod based low turn-on voltage LEDs with wide electroluminescence spectra

    刊名:Journal of Luminescence 作者:S.K. Jha ; O. Kutsay ; I. Bello ; S.T. Lee 关键词:ZnO nanorod; White LED; Blue LED; Hydrothermal; GaN; Heterostructure 年份:2013
    摘要:Light emitting diodes (LEDs) based on arrays of n-type ZnO Nanorods were fabricated on p-GaN films using a hydrothermal method. The LEDs emit mainly in blue and UV range of the light. Their current-Voltage (I-V) characteristics typically show a low leakage current (7.2 μA) and a high rectification ratio (3 5 5). Devices operate at a low turn-on voltage of ?.5 V. Photoluminescence (PL) and electroluminescence (EL) measurements suggest low density of ZnO defects; however, in some aspects density of interfacial defects still might be considerable in the studied devices. The PL emission is deconvoluted to three peaks that are located at wavelengths of 361, 381, and 397 nm, while the wide EL spectra are deconvoluted to five peaks appearing at 368, 385, 427, 474, and 515 nm. Near-band-edge (NBE) emission of p-GaN and n-ZnO was observed in both the PL and EL spectra. Deconvoluted EL spectra consist of a very wide green band with the peak at 515 nm and extending up to 650 nm (red), and a rarely reported EL emission at 474 nm. Origin of these emissions is discussed, herein. The electrical characteristics together with EL characteristics indicate potential to develop and study p-GaN/n-ZnO nanorod LEDs for white emitting applications.
  • 【期刊】 Spatial distribution of fallout 137Cs in the coastal marine environment of India

    摘要:The data on the fallout 137Cs in the coastal marine environment assume significance in view of massive expansion of nuclear power plants in the Asia-Pacific region and to fulfill the benchmark study required to evaluate the possible impact of the Fukushima radioactive releases in the Asia-Pacific region. Measurements of 137Cs in sea water, along with salinity and temperature, were carried out at 30 locations covering the coastal area of the Arabian Sea and the Bay of Bengal. For the present study the Indian coastal area is divided in three different regions. The 137Cs concentration in sea water of the entire Indian coastal region varies from 0.30 to 1.25 Bq m -3. The data obtained in the present study was compared with the North Indian Ocean data and it was observed that there is a 33% decrease in the Arabian Sea (region I), 50% in the high rainfall coastal area (region II) and 24% in the Bay of Bengal (region III).
  • 【期刊】 Low-frequency noise properties of double channel AlGaN/GaN HEMTs

    摘要:Low-frequency noise in MOCVD-grown AlGaN/GaN/AlGaN/GaN double channel high electron mobility transistors (HEMTs) on sapphire substrate was investigated over a wide range of temperatures from 80 K to 300 K. Generation–recombination (g–r) noise was observed arising from the traps with activation energies 140 meV, 188 meV and 201 meV. Hooge parameter was estimated to be 1.6 × 10−3 at room temperature. Our work demonstrates good dc and low-frequency noise properties for the device.
  • 【期刊】 Response of spinach (Spinacea oleracea

    刊名:Food and Chemical Toxicology 作者:S.K. Jha ; A.K. Nayak ; Y.K. Sharma 关键词:Fluoride; Spinach; Contamination; Partitioning; Phyto-toxicity 年份:2008
    摘要:The influence of soil contamination by inorganic fluoride (NaF) on the uptake and accumulation of fluoride in the shoot and root of spinach (Spinacea oleracea) was investigated in pot experiment under controlled conditions. The soluble fluoride in soil varied between 2.57 mg kg−1 soil and 16.44 mg kg−1 soil in the treatment range of 0–800 mg NaF kg−1 soil. It was found that the concentration of the total fluoride in shoot and root varied between 23.5 mg kg−1 dry wt. (control) and 219.8 mg kg−1 dry wt. (at 800 mg NaF kg−1 soil). The fluoride concentration in shoot and root showed a linear trend. At the added fluoride concentration beyond 200 mg NaF kg−1 of soil, the spinach root retained more fluoride than shoot. In the treatment range 0–800 mg NaF kg−1 soil, the water labile fluoride in the juice varied from 0.32 to 0.78 ppm in shoot and 1.03 to 2.79 ppm in the root. No visible symptom of phyto-toxicity was noticed with the treatment from 0 to 800 mg NaF kg−1 soil. It was inferred from this study that spinach (S. oleracea) accumulates fluoride at tissues level and has a distinct mechanism of partitioning of water labile fluoride and total fluoride in the tissues.
  • 【期刊】 Low-frequency noise properties of double channel AlGaN/GaN HEMTs

    摘要:Low-frequency noise in MOCVD-grown AlGaN/GaN/AlGaN/GaN double channel high electron mobility transistors (HEMTs) on sapphire substrate was investigated over a wide range of temperatures from 80 K to 300 K. Generation–recombination (g–r) noise was observed arising from the traps with activation energies 140 meV, 188 meV and 201 meV. Hooge parameter was estimated to be 1.6 × 10−3 at room temperature. Our work demonstrates good dc and low-frequency noise properties for the device.
  • 【期刊】 Physical characteristics of compressed cotton stalks

    刊名:Biosystems Engineering 作者:S.K. Jha ; Amar Singh ; Adarsh Kumar 年份:2008
    摘要:A study was carried out to evaluate the physical characteristics of chopped cotton stalks and to establish correlations of physical characteristics with moisture content and compression pressure. Chopped cotton stalks having a moisture content varying from 8.5% to 21.45% (w.b.) were densified into square blocks (80 mm by 80 mm) at compression pressures ranging between 13.79 and 34.47 MPa and a dwell time of 1 min, using a vertical compaction machine. Physical characteristics of blocks, namely bulk density, compression ratio, resiliency and hardness, were evaluated. The bulk density of blocks varied from 542 to 794kgm(-3), resiliency from 11% to 47%, hardness from 15 to 134kg and compression ratio from 5.2 to 8.6. Analysis of variance indicated significant effects of moisture content and compression pressure on bulk density, resiliency and hardness of compressed cotton stalk blocks. A second-order polynomial was found to be adequate to correlate the physical characteristics of blocks with moisture content and compression pressure. A compression pressure of 34 MPa and a moisture content of 15% (w.b.) were found to be the most appropriate for high stability compressed blocks. Savings in transportation costs in block form could be up to 76% whereas maximum savings in storage cost of blocks could be as much as 88%. (C) 2007 IAgrE. Published by Elsevier Ltd. All rights reserved.
  • 【期刊】 Valve Positioning Control for Process Through-put Maximization

    摘要:The application of a valve positioning controller (VPC) on top of a basic regulatory plant-wide control structure for maximizing the process through-put to increase plant profitability is demonstrated. The input to the VPC is a measurement of the bottleneck constraint and its output is the set-point of the through-put manipulator. The hydrodealkylation (HDA) of toluene to benzene process is used as an example case study with the feed hydrogen compressor and the furnace considered as bottleneck constraints that limit production. Results show that the automatic adjustment of the through-put manipulator allows the process to be operated close to (or at) the bottleneck constraint. De-rating of the plant through-put due to the possibility of disturbances is then avoided resulting in enhanced through-puts and plant operating profit. The increase in the through-put and plant profit over the de-rated operation is quantified with respect to variation in the magnitude of the principal disturbance that causes the bottleneck constraint to be hit. Results show that significant enhancement of more than 10% increase operating profit can be achieved. VPC is thus demonstrated to be a simple and effective means for increasing plant profitability by maximizing through-put.
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