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Physics design of 14 meV neutron generator facility at the Institute for Plasma Research

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Plasma Science and Technology 2023年第12期25卷 115-121页

作者： H L SWAmI S VALA m RAJPUT m ABHANGI Ratnesh KUmAR A saxena Rajesh KUmAR Institute for Plasma Research Gandhinagar 382428India Homi Bhabha National Institute Training School ComplexMumbai 400094India

A high energy and high yield neutron source is a prime requirement for technological studies related to fusion reactor development. It provides a high-energy neutron environment for small-scale fusion reactor components research and testing such as tritium breeding, shielding, plasmafacing materials, reaction cross-section data study for fusion materials, etc. Along with ITER participation, the Institute of Plasma Research, India is developing an accelerator-based 14 meV neutron source with a yield of 10^(12)n s^(-1). The design of the source is based on the deuterium–tritium fusion reaction. The deuterium beam is accelerated and delivered to the tritium target to generate 14 meV neutrons. The deuterium beam energy and tritium availability in the tritium target are the base parameters of the accelerator-based neutron source design. The paper gives the physics design of the neutron generator facility of the Institute for Plasma Research. It covers the requirements, design basis, and physics parameters of the neutron generator. As per the analytical results generator can produce more than 1 × 10^(12)n s^(-1)with a 110 keV D^(+) ion beam of 10 mA and a minimum 5 Ci tritium target. However, the detailed simulation with the more realistic conditions of deuteron ion interaction with the tritium titanium target shows that the desired results cannot be achieved with 110 keV. The safe limit of the ion energy should be 300 keV as per the simulation. At 300 keV ion energy and 20 mA current, it reaches 1.6 × 10^(12)n s^(-1). moreover, it was found that to ensure sufficiently long operation time a tritium target of more than 20 Ci should be used. The scope of the neutron source is not limited to the fusion reactor research studies, it is extended to other areas such as medical radioisotopes research, semiconductor devices irradiations, and many more.

关键词： neutron generator neutronics accelerator physics design nuclear fusion

mATHEmATICAL ESTImATION OF PHYSIOLOGICAL DISTURBANCES IN HUmAN DERmAL PARTS AT EXTREmE CONDITIONS:ONE DImENSIONAL STEADY STATE CASE

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Analysis in Theory and Applications 2009年第4期25卷 325-332页

作者： m.A.Khanday V.P.saxena University of Kashmir Srinagar India Jiwaji University India

A mathematical model for the thermoregulation in the dermal layers of the human body is proposed. The skin is composed mainly of three layers - epidermis, dermis and subcutaneous tissues. The relative constancy of the body temperature is remarkable because there is a continuous exchange of heat with the external environment as well as within the different compartments of the body. A model describes the distribution of dermal tempera- ture as a function of internal and external parameters, such as temperature of the incoming arterial blood, blood flow, ambient temperature, and heat exchange with the environment. It is shown that substantial changes in human dermal temperature can be accomplished only through changes in the temperature of the incoming arterial blood or substantial suppression of blood flow. Other parameters can lead only to temperature changes near the skin surface.

关键词： thermoregulation metabolism blood flow skin response bio-heat equation,mathematical model

mATHEmATICAL STUDY OF DIFFUSIVE FLUID TRANSPORT AND DISTRIBUTION IN HUmAN DERmAL REGIONS

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Analysis in Theory and Applications 2010年第4期26卷 350-358页

作者： m. A. Khanday V. P. saxena University of Kashmir Hazratbal Srinagar School of mathematics and Allied Sciences Jiwaji University

This paper deals with mathematical study of diffusive fluid transport and distri- bution in human dermal parts. It accounts the intracellular fluid which continuously flows through the skin shells in order to maintain fluid balance within the body. A mathematical model is envisaged for this process and the finite element method （FEm） is employed to calculate the concentration of the fluid at different skin layers. This estimation is analyzed in relation with other parameters of the tissue medium and the atmosphere.

关键词： human body response fluid concentration skin layers mathematical model

Integrated physiological and molecular approaches to improvement of abiotic stress tolerance in two pulse crops of the semi-arid tropics

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The Crop Journal 2018年第2期6卷 99-114页

作者： arbind k.choudhary rafat sultana m.isabel vales kul bhushan saxena ravi ranjan kumar pasala ratnakumar ICAR Research Complex for Eastern Region Patna 800 014India Bihar Agricultural University SabourBhagalpur 813 210India Texas A&m University College StationTX 77845USA International Crops Research Institute for the Semi-Arid Tropics Patancheru 502 324India National Institute of Abiotic Stress management Baramati 413 115India

Chickpea(Cicer arietinum L.) and pigeonpea [Cajanus cajan L.(millsp.)] play an important role in mitigating protein malnutrition for millions of poor vegetarians living in regions of the semi-arid tropics. Abiotic stresses such as excess and limited soil moisture(water-logging and drought), heat and chilling(high and low temperature stresses), soil salinity, and acidity are major yield constraints, as these two crops are grown mostly under rainfed conditions in risk-prone marginal and degraded lands with few or no inputs. Losses due to such stresses vary from 30% to 100% depending on their severity. The literature abounds in basic information concerning screening techniques, physiological mechanisms, and genetics of traits associated with resistance/tolerance to abiotic stresses in these two crops. However, the final outcome in terms of resistant/tolerant varieties has been far from satisfactory. This situation calls for improving selection efficiency through precise phenotyping and genotyping under high-throughput controlled conditions using modern tools of genomics. In this review, we suggest that an integrated approach combining advances from genetics, physiology, and biotechnology needs to be used for higher precision and efficiency of breeding programs aimed at improving abiotic stress tolerance in both chickpea and pigeonpea.

关键词： Abiotic stresses Chickpea Genomics Genotyping Integrated approach Pigeonpea

Source apportionment of Pm10 in Delhi, India using PCA/APCS, UNmIX and PmF

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Particuology 2018年第2期16卷 107-118页

作者： Srishti Jain S.K. Sharma T.K. mandal mohit saxena Environmental Sciences and Biomedical metrology Division CSIR-National Physical Laboratory Dr. K. S. Krishnan Road New Delhi 110 012 India Academy of Scientific and Innovative Research (AcSIR) CSIR-National Physical Laboratory campus New Delhi 110 012 India

Source apportionment of particulate matter （Pm10） measurements taken in Delhi, India between January 2013 and June 2014 was carried out using two receptor models, principal component analysis with absolute principal component scores （PCA/APCS） and UNmIX. The results were compared with previous estimates generated using the positive matrix factorization （PmF） receptor model to investigate each model＇s source-apportioning capability. All models used the Pm10 chemical composition （organic carbon （OC）, elemental carbon （EC）, water soluble inorganic ions （WSIC）, and trace elements） for source apportionment. The average Pm10 concentration during the study period was 249.7±103.9 μg/m3 （range： 61.4-584.8 μg/m3）. The UNmIX model resolved five sources （soil dust （SD）, vehicular emissions （VE）, secondary aerosols （SA）, a mixed source of biomass burning （BB） and sea salt （SS）, and industrial emissions （IE））. The PCA/APCS model also resolved five sources, two of which also included mixed sources （SD, VE, SD＋SS, （SA＋BB＋SS） and 1E）. The PmF analysis differentiated seven individual sources （SD, VE, SA, BB, SS, IE, and fossil fuel combustion （FFC））. All models identified the main sources contributing to Pm10 emissions and reconfirmed that VE, SA, BB, and SD were the dominant contributors in Delhi.

关键词： Receptor model PCA/APCS UNmIX PmF Source apportionment

Evaluation of retinal nerve fiber layer thickness profile in thyroid ophthalmopathy without optic nerve dysfunction

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International Journal of Ophthalmology(English edition) 2016年第11期9卷 1634-1637页

作者： Kumari mugdha Apjit Kaur Neha Sinha Sandeep saxena Department of Ophthalmology King George's Medical University Lucknow 226003 India Sankara Eye Hospital Kanpur 208001 India

AIm： To evaluate retinal nerve fiber layer（RNFL）thickness profile in patients of thyroid ophthalmopathy with no clinical signs of optic nerve ***： A prospective, case-control, observational study conducted at a tertiary care centre. Inclusion criteria consisted of patients with eyelid retraction in association with any one of： biochemical thyroid dysfunction, exophthalmos, or extraocular muscle involvement; or thyroid dysfunction in association with either exophthalmos or extra-ocular muscle involvement;or a clinical activity score（CAS）〉3/7. Two measurements of RNFL thickness were done for each eye, by Cirrus HD-optical coherence tomography 6mo ***： mean age of the sample was 38.75y（range13-70y） with 18 males and 22 females. Average RNFL thickness at first visit was 92.06 ±12.44 μm, significantly lower than control group（101.28±6.64 μm）（P =0.0001）.Thickness of inferior quadrant decreased from 118.2 ±21.27 μm to 115.0 ±22.27 μm after 6mo（P =0.02）. There was no correlation between the change in CAS and RNFL thickness. CONCLUSION： Decreased RNFL thickness is an important feature of thyroid orbitopathy, which is an inherent outcome of compressive optic neuropathy of any etiology. Subclinical RNFL damage continues in the absence of clinical activity of the disease. RNFL evaluation is essential in Grave＇s disease and active intervention may be warranted in the presence of significant damage.

关键词： thyroid ophthalmopathy retinal nerve fibrelayer optical coherence tomography

High Oxygen Nanocomposite Barrier Films Based on Xylan and Nanocrystalline Cellulose

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Nano-micro Letters 2010年第4期2卷 235-241页

作者： Amit saxena Thomas J.Elder Jeffrey Kenvin Arthur J.Ragauskas School of Chemistry and Biochemistry Georgia Institute of Technology USDA-Forest Service Southern Research Station micromeritics Instrument Corporation

The goal of this work is to produce nanocomposite film with low oxygen permeability by casting an aqueous solution containing xylan,sorbitol and nanocrystalline *** morphology of the resulting nanocomposite films was examined by scanning electron microscopy and atomic force microscopy which showed that control films containing xylan and sorbitol had a more open structure as compared to xylan-sorbitol films containing sulfonated nanocrystalline *** average pore diameter,bulk density,porosity and tortuosity factor measurements of control xylan films and nanocomposite xylan films were examined by mercury intrusion porosimetry *** films reinforced with nanocrystalline cellulose were denser and exhibited higher tortuosity factor than the control xylan *** xylan films had average pore diameter,bulk density,porosity and tortuosity factor of 0.1730 μm,0.6165 g/ml,53.0161% and 1.258,respectively as compared to xylan films reinforced with 50% nanocrystalline cellulose with average pore diameter of 0.0581 μm,bulk density of 1.1513 g/ml,porosity of 22.8906% and tortuosity factor of *** transmission rate tests demonstrated that films prepared with xylan,sorbitol and 5%,10%,25% and 50% sulfonated nanocrystalline cellulose exhibited a significantly reduced oxygen permeability of 1.1387,1.0933,0.8986 and 0.1799 cm^3×μm/m^2×d×k Pa respectively with respect to films prepared solely from xylan and sorbitol with a oxygen permeability of 189.1665 cm^3×μm/m^2×d×k *** properties suggested these nanocomposite films have promising barrier properties.

关键词： Nanocomposites Xylan Nanocrystalline cellulose Oxygen barrier

Hydrodynamic and Heat Transfer Characteristics of magnetofluidized Beds

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Journal of Thermal Science 1994年第3期3卷 211-215页

作者： S.C.saxena R.Z.Qian DepartmentofChemicalEngineering TheUniversityofIllinoisChicagoIL60607－7000USA DepartmentofPowerEng

To investigate the flow and heat-transfer behaviors of magnetofluidized beds, an experimental facilitywas designed. A constant uniform magnetic field is produced by a Helmholtz electromagnet. The nature of fiuidization and heat-transfer characteristics of a horizontal electrically heated tube immersed in the bed were measured. The bed material is iron shots. Depending upon the intensity of magnetic field (weak, moderate and strong), the bed pressure drop and heat transfer coefficient are classified into three ranges of magnetic fields. The range of variation of maximum magnetic-field intensity is from 0 to about 20690 A/m.

关键词： magnetofiuidised beds beat trarefer hydrodynamic characteristics

Heat Transfer and Hydrodynamic Investigations of a Baffled Slurry Bubble Column

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Journal of Thermal Science 1992年第3期1卷 178-183页

作者： S. C. saxena Z. D. Chen Department of Chemical Engineering The University of Illinois at Chicago Box 4348 Chicago IL 60680 U.S.A.

Heat transfer and hydrodynamic investigations have been conducted in a 0.108 m internal diameter bubble column at ambient conditions. The column is equipped with seven 19mm diameter tubes arranged in an equilateral triangular pitch of 36.5 mm. A monsanto synthetic heat transfer fluid, Therminol-66 having a viscosity of 39.8 cP at 303 K, is used as a liquid medium. magnetite powders, average diameters 27.7 and 36.6 μm, in five concentrations up to 50 weight percent in the slurry, are used. As a gas phase, industrial grade nitrogen of purity 99.6 percent is employed. Gas holdup in different operating modes and regimes have been measured for the two- and three-phase systems over a superficial gas velocity range up to 0.20 m/s in the semi-batch mode. Heat transfer coefficients are measured at different tube locations in the bundle at different radial and vertical locations over a range of operating conditions. All these data are compared with the existing literature correlations and models. New correlations are proposed.

关键词： heat transfer coefficient gas-phase holdup slurry bubble column.