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Effects of resistivity on standing shocks in low angular momentum flows around black holes

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Research in Astronomy and Astrophysics 2021年第6期21卷 222-232页

作者： chandra b.singh Toru Okuda Ramiz Aktar South-Western Institute for Astronomy Research Yunnan UniversityKunming 650500China Hakodate Campus Hokkaido University of EducationHachiman-Cho 1-2HakodateHokkaido 040-8567Japan Department of Astronomy Xiamen UniversityXiamen 361005China

We study two-dimensional low angular momentum flow around a black hole using the resistive magnetohydrodynamic module of pLUTO *** have been performed for the flows with parameters of specific angular momentum,specific energy and magnetic field which may be expected for the flow around Sgr A*.For flows with lower resistivityη=10^(-6)and 0.01,the luminosity and shock location on the equator vary *** power density spectra of luminosity variation show peak frequencies which correspond to the periods of 5×10^(5),1.4×10^(5)and 5×10^(4)*** quasi-periodic oscillations(QpOs)occur due to interaction between the outer oscillating standing shock and the inner weak shocks occurring at the innermost hot *** for cases with higher resistivityη=0.1 and 1.0,the high resistivity considerably suppresses the magnetic activity such as MHD turbulence and the flows tend to be steady and symmetric with respect to the *** steady standing shock is formed more outward compared with the hydrodynamical *** low angular momentum flow model with the above flow parameters and with low resistivity has a possibility to explain long-term flares of Sgr A*with frequencies~one per day and~5-10 days in the latest observations by chandra,Swift and XMM-Newton monitoring of Sgr A*.

关键词： accretion accretion disks magnetohydrodynamics(MHD) methods:numerical shock waves Galaxy:center

Machine learned interatomic potentials using random features

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npj Computational Materials 2022年第1期8卷 48-57页

作者： Gurjot Dhaliwal prasanth b.Nair chandra Veer singh Department of Mechanical and Industrial Engineering University of Toronto5 King’s College RdTorontoM5S 3G8ONCanada Institute for Aerospace Studies University of Toronto4925 Dufferin StTorontoM3H 5T6ONCanada Department of Materials Science and Engineering University of Toronto184 College StTorontoM5S 3E4ONCanada

We present a method to model interatomic interactions such as energy and forces in a computationally efficient *** proposed model approximates the energy/forces using a linear combination of random features,thereby enabling fast parameter estimation by solving a linear least-squares *** discuss how random features based on stationary and non-stationary kernels can be used for energy approximation and provide results for three classes of materials,namely two-dimensional materials,metals and *** and energy predictions made using the proposed method are in close agreement with density functional theory calculations,with training time that is 96%lower than standard kernel *** Dynamics calculations using random features based interatomic potentials are shown to agree well with experimental and density functional theory *** frequencies as computed by random features based interatomic potentials are within 0.1%of the density functional theory ***,the proposed random features-based potential addresses scalability issues encountered in this class of machine learning problems.

关键词： random stationary interatomic

Vascular plants distribution in relation to topography and environmental variables in alpine zone of Kedarnath Wild Life Sanctuary,West Himalaya

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Journal of Mountain Science 2018年第9期15卷 1936-1949页

作者： chandra Sudeep singh Ankit singh C.p. NAUTIYAL M.C. RAWAT L.S. High Altitude plant physiology Research Centre(HAppRC)H.N.b.Garhwal University Srinagar Garhwal-246174UttarakhandIndia Space Applications Centre (Indian Space Research Organization)Ahmedabad 380015India Govind ballabh pant National Institute of Himalayan Environment&Sustainable Development Garhwal Unit Srinagar Garhwal-246174UttarakhandIndia

The present study was carried out in Tungnath alpine meadows of Kedarnath Wild Life Sanctuary, Western Himalaya from subalpine to upper alpine zone. A total of four summits were selected along an altitudinal gradient and sampled for detailed vegetation analysis using multi summit approach as per Global observation research initiative in alpine environments(GLORIA). Species richness, diversity, and evenness among four summits as well as the interaction between environmental variables with plant communities were assessed. Monthly mean soil temperature was calculated using data retrieved from geo-precision temperature logger in order to identify the trend of soil temperature among different season and altitudinal gradient and its implications to plant communities. Soil samples were analyzed fromeach summit by collecting randomized composite soil samples. The indirect non-metric multidimensional scaling(NMDS) and direct canonical correspondence analysis(CCA) tools of ordination techniques to determine the linkage between plant species from various sample summits and biotic/abiotic environmental gradients were used in the present study. The results of the study demonstrated increase in species richness as soil temperature increases, the ecotone representing summits were found most warm summits followed by highest species richness. Annual soil temperature increased by 1.43°C at timberline ecotone. Whereas, at upper alpine zone the soil temperature increased by 0.810 C from year 2015 to 2016. S?rensen's similarity index was found to be increased between subalpine and upper alpine zone with increase in the presence of subalpine plant species at upper alpine zone. both the ordination tools separate the subalpine summit and their respective vegetation from summits representingtimberline ecotone and upper alpine zone. Soil p H, altitude, soil cation exchange capacity were found as the key abiotic drivers for distribution of plant species.

关键词： GLORIA Non-metric multidimensionalscaling (NMDS) Canonical correspondence analysis(CCA) Ecotone West Himalaya

Crop productivity,soil health,and energy dynamics of Indian Himalayan intensified organic maize-based systems

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International Soil and Water Conservation Research 2021年第2期9卷 260-270页

作者： Raghavendra singh Subhash babu R.K.Avasthe Gulab singh Yadav Anup Das K.p.Mohapatra Amit Kumar Vinod K.singh puran chandra ICAR-National Organic Farming Research Institute GangtokSikkim737102India Division of Agronomy ICAR-Indian Agricultural Research InstituteNew Delhi110012India ICAR Research Complex for NEH Region Tripura CentreLembucherraTripura799210India ICAR-National bureau of plant Genetic Resources New Delhi110012India

The sustainability of prevailing maize-fallow system in rainfed ecosystems of the Eastern Himalayan region(EHR)of India is often questioned due to poor economic return and negative impact on soil ***,the six cropping systems,maize-fallow(M-F),maize t cowpea-rapeseed(M t C-Rs),maize t cowpea-buckwheat(M t C-bw),maize t cowpea-barley(M t Ceb),maize t cowpea-garden pea(M t C-Gp)and maize t cowpeaerajmash(M t C-R)in the main plot and three soil moisture conservation measures,no-mulch(NM),maize stover mulch(MSM)and maize stover t weed biomass mulch(MSM t WbM)in sub-plot were evaluated for four consecutive years(2014-18)at a Research Farm in fixed plot *** indicated that cowpea co-culture with maize and inclusion of winter crop increased maize yield by 6.2e23.5%over *** the systems,the M t C-Gp recorded the highest crop *** residual effect of MSM t WbM increased maize grain yield by 19.1%over *** of maize t cowpea-winter crops significantly improved the available N(3.2e12.9%),p(3.6 e12.7%),K(1.9e26.3%),organic carbon(9.2e16.8%),microbial biomass carbon-MbC(15.2e43.9%)and dehydrogenases-DHA(17.2e42.3%)in soil at 0e15 cm depth as compared to *** M t C-Gp also recorded maximum net return(US$2460 ha1),benefit:cost(b:C)ratio(2.86)and energy use efficiency(7.9%).The MSM t WbM recorded higher net return(US$1680 ha1)and b:C ratio(2.46)over ***,cowpea t maize-garden pea(M t C-Gp)along with the application of MSM t WbM is a sustainable production practice to intensify the organically managed maize-fallow system in rainfed regions of the EHR of India and other similar ecosystems.

关键词： Crop intensification Energy productivity Gross return Soil health Water productivity

Feature-based augmentation and classification for tabular data

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CAAI Transactions on Intelligence Technology 2022年第3期7卷 481-491页

作者： balachander Sathianarayanan Yogesh chandra singh Samant prahalad S.Conjeepuram Guruprasad Varshin b.Hariharan Nirmala Devi Manickam Amrita School of Engineering Amrita Vishwa VidyapeethamCoimbatoreIndia

Generating synthetic samples for a tabular data is a strenuous *** of the time,the columns(features)in the dataset may not follow an ideal distribution *** objective of the proposed algorithm,Histogram Augmentation Technique(HAT),is to generate a dataset whose distribution is similar to that of the original *** augmentation is achieved based on individual columns,where separate algorithms are designed for continuous and discrete *** also use features of an object for *** humans make a judgement,they notice prominent features and characterise the perceived ***,conventional Machine Learning classifiers are designed and trained on the basis of *** the features as the basis for classification,Feature Importance Classifier(FIC)has been attempted in this *** treats every feature independent of each other,and ranks the features based on its dependence with the classified *** has been found that the FIC has the highest accuracy and has improved the accuracy by 5.54%on average,when it's compared to other *** suggested algorithms have been experimented on five datasets and compared with two augmentation algorithms and four state-of-the-art ML classification algorithms.

关键词： function classifier columns

Optimization of substrate ratio for beer production from finger millet and barley

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International Journal of Agricultural and biological Engineering 2015年第2期8卷 110-120页

作者： Sanjay Kumar Anupama singh Navin chandra Shahi Khan Chand Kopal Gupta Department of post-harvest process&Food Engineering College of TechnologyG.B.Pant University of Agriculture and TechnologyPantnagar 263145Udham Singh NagarUttarakhandIndia

Seventeen designed experiments were conducted in three steps(malting,brewing and fermentation)to produce beer from barley,finger millet and the combination of *** of independent variables with three levels for each *** ratios of grains(100:0,50:50,0:100),kilning temperature(50℃,70℃,90℃)and malted grain to water ratios(1:3,1:5,1:7)were investigated on product *** results of the study indicated that all the independent parameters *** ratio,kilning temperature and slurry ratio affected the responses(pH,colour,bitterness and alcohol content)*** values of parameters,from the simultaneous optimization done using Design Expert 8.***.6.1 software,for beer production,were found to be 68:32 blend ratio,50℃ kilning temperature and 1:7 slurry *** model F-value was found to be highly significant at 1% level of significance for all the *** the responses could be predicted by fitting the second order mathematical model and adequacy checked by R^(2).

关键词： beer production fermentation technology blend ratio alcohol content bitterness finger millet barley

Induced polyploidy via Colchicine Treatment Increases Flower Size and Fruit Weight in Cape Gooseberry(physalis peruviana L.)

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Journal of Agricultural Science and Technology(b) 2020年第3期10卷 144-155页

作者： Ravindra Kumar Shubhranshu Sengupta Sanyat Misra satish chandra Narayan Kamleshwari prasad singh Department of Horticulture Birsa Agricultural UniversityKankeRanchi-834006JharkhandIndia Department of plant breeding and Genetics Birsa Agricultural UniversityKankeRanchi-834006JharkhandIndia Krishi Vigyan Kendra Katihar-854103Bihar Agricultural UniversitySabourBhagalpur-813210BiharIndia

An induced polyploid plant through colchicine treatment offers probably the best scope for improvement in flower size and fruit ***,in the present study,an attempt was made to induce polyploidy in Cape gooseberry using colchicine with the objective of creating more genetic *** colchicine concentrations were used as 0.10%(C1),0.20%(C2)and 0.40%(C3)for the duration 12(H1),24(H2)and 36(H3)hours for each concentration with seedling apex dip method(M1),cotton plug method(M2)and lanolin paste method(M3).The plants treated with 0.10%of colchicine by cotton plug method for 12 h showed the better performance during the years 2017-2018 and 2018-2019 in respect of more delay in the flower bud emergence(54 d and 53 d from the date of transplanting),anthesis(19 d and 20 d from the first appearance of bud to full anthesis of flower)and fruit setting(8.00 d and 9.00 d from the date of anthesis),bigger flower size(2.93 cm2 and 3.00 cm2)than the untreated *** lower percentage of pollen viability(40.33%and 40.67%)was noticed in the same treatment in comparison to control(70.33%and 72.33%).The fruit maturity was also extended(59 d and 60 d from the date of fruit set)with bigger sized fruits(length:2.53 cm and 2.57 cm,breadth:2.27 cm and 2.33 cm)as well as more fruit weight(8.70 g and 8.33 g)by the application of colchicine at 0.10%with cotton plug method for 12 *** the basis of results obtained,the application of colchicine at 0.10%for 12 h duration with cotton plug method was found to be the best and effective treatment for induction of polyploidy as well as more flower size and fruit weight in Cape gooseberry.

关键词： Cape gooseberry colchicine polyploid flower size fruit weight.

Outcome of application of primary versus secondary Illizarov＇s fixator in open tibial shaft fractures

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World Journal of Emergency Medicine 2016年第3期7卷 221-226页

作者： Anil Joshi Saurabh singh Sudeep Jain Narender Rohilla Vivek Trikha chandra Yadav Medical College V.C.S.G. Government Medical Sciences and Research Institute Srinagar Pauri Garhwal India H.N.b. base & Teaching Hospital P O.-Srikot Srinagar Srinagar Garhwal Uttarakhand 246174 India Department of Orthopaedics IMS BHU Varanasi India Varanasi Uttar Pradesh 221005 India Fortis Flt Lt Rajah Dhall Hospital Ringgold Standard Institution Safdarjung Enclave New Delhi Delhi 110070 India Fortis Hospital Shalimar Bagh Ringgold Standard Institution Safdarjung Enclave New Delhi Delhi 110033 India Department of Orthopaedics All India Institute of Medical Sciences Ringgold Standard Institution New Delhi Delhi 110029 India

bACKGROUND: The present study aimed to compare outcome of primary and secondary Illizarov's fi xator application as a treatment method for type III open tibial fractures in terms of nonunion and wound ***: This prospective study was done in a tertiary care center. Forty-eight type III tibial fractures were treated with Illizarov's apparatus between 2008 and 2011. The patients were divided into two groups depending on the treatment protocol, timing of wound closure and Illizarov's application, primary(n=28) and secondary(n=20).RESULTS: In the primary group, healing was achieved in all 28 patients. The median time to recovery was 24 weeks, and the median number of operations was 3. There were 6 patients with a bone defect. In the secondary group, complete recovery was achieved in 18 out of 20 patients. The median time to recovery was 30 weeks, and the median number of operations 5. There were 9 patients with a bone defect. The median time to recovery and the number of operations were signifi cantly smaller in patients undergoing primary operation. Union was 100% in the primary group and more than 95% in the secondary group. Chronic osteomyelitis persisted in one patient and below amputation was done in one patient in the secondary ***: primary wound closure and Illizarov's fixation required a smaller number of operations and shorter time to recovery than secondary wound closure and Illizarov's fi xation, mostly due to a signifi cantly less number of patients with a bone defect in the primary group.

关键词： Open fractures Limb salvage Debridement Illizarov’s fi xator Tibial fractures

The redshift distribution of bL Lacs and FSRQs

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Research in Astronomy and Astrophysics 2019年第1期19卷 131-140页

作者： David Garofalo chandra b.singh Dylan T.Walsh Damian J.Christian Andrew M.Jones Alexa Zack brandt Webster Matthew I.Kim Department of physics Kennesaw State University The Raymond and beverly Sackler School of physics and Astronomy Tel Aviv University Department of physics & Astronomy California State University boise State University Computational Science & Engineering

Flat spectrum radio quasars(FSRQs) and bL Lacertae objects(bL Lacs) are powerful jet producing active galactic nuclei associated with supermassive black holes accreting at high and low Eddington rates, respectively. based on the Millennium Simulation, Gardner & Done have predicted their redshift distribution by appealing to ideas from the spin paradigm in a way that exposes a need for a deeper discussion on three interrelated issues:(1) an overprediction of bL Lacs compared to FSRQs;(2) a difference in FSRQ and bL Lac distributions;(3) a need for powerful but different jets at separated cosmic times. beginning with Gardner & Done's determination of Fermi observable FSRQs based on the distribution of thermal accretion across cosmic time from the Millennium Simulation, we connect FSRQs to bL Lacs by way of the gap paradigm for black hole accretion and jet formation to address the above issues in a unified way. We identify a physical constraint in the paradigm for the numbers of bL Lacs that naturally leads to separate peaks in time for different albeit powerful jets. In addition, we both identify as puzzling and ascribe physical significance to a tail end in the bL Lac curve versus redshift that is unseen in the redshift distribution for FSRQs.

关键词： black hole physics bL Lacertae objects:general galaxies:ets gamma-rays:galaxies