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Synthesis of micron-sized Hexagonal and Flowerlike Nanostructures of Lead Oxide (PbO_2) by Anodic Oxidation of Lead

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Nano-micro Letters 2011年第4期3卷 223-227页

作者： dinesh Pratap singh Onkar Nath Srivastava Estación Central Departamento de Física Department of Physics Banaras Hindu University

micron sized hexagon- and flower-like nanostructures of lead oxide（α-PbO2） have been synthesized by very simple and cost effective route of anodic oxidation of lead sheet. These structures were easily obtained by the simple variation of applied voltage from 2-6 V between the electrodes. Lead sheet was used as an anode and platinum sheet served as a cathode. Anodic oxidation at 2 V resulted in the variable edge sized（1-2 μm） hexagon-like structures in the electrolyte. When the applied potential was increased to 4 V a structure of distorted hexagons consisting of some flower-like structures were obtained. Further increment of potential up to 6 V resulted in flower like structures of α-PbO2 having six petals. The diameter of the flower-like structures was 200-500 nm and the size of a petal was 100-200 nm.

关键词： Lead oxide nanostructures Anodic oxidation Hexagon-like structures Flower-like nanostructures

Nanostructured porous polyaniline(PANI)coated carbon cloth(CC)as electrodes for flexible supercapacitor device

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Journal of materials Science & Technology 2021年第29期88卷 168-182页

作者： dinesh J.Ahirrao Ajay Kumar Pal Vikalp singh Neetu Jha Department of Physics Institute of Chemical TechnologyMatunga(E)Mumbai400019India Department of Physics Ramniranjan Jhunjhunwala CollegeGhatkopar(W)Mumbai 400086India

Nanostructured porous polyaniline(PANI)has been synthesized and coated simultaneously on a highly flexible and conductive carbon cloth(CC)substrate using a simple in-situ chemical oxidative polymerization *** coated CC(PANI-CC)based flexible electrodes were further used for the fabrication of flexible supercapacitor *** the comparison purpose,pure PANI has also been synthesized and tested for its electrochemical *** energy storage capacity of PANI and PANI–CC composite was investigated using electrochemical techniques like CV,GCD,and EIS in a potential range from 0 to 0.8 V in 1 m H_(2)SO_(4)***-CC flexible electrodes exhibited the highest specific capacitance of 691 F/g;whereas,pure PANI could only achieve 575 F/g of specific capacitance at 1 A/*** also exhibited outstanding cyclic stability by recollecting 94%of its initial capacitance after 2000 GCD *** actual implementation,a flexible supercapacitor device has been fabricated using stainless steel sheets and PANI-CC flexile *** energy storage performance of the PANI-CC flexible supercapacitor device was tested at several bending angles,which resulted in 72%of capacitance retention at a maximum bending angle of 140°compared to the capacitance obtained at an angle 0°(flat state).PANI-CC exhibited improved electrochemical performance than pure PANI due to the synergistic effect between PANI and ***,CC helped in enhancing the conductivity and stability;whereas,PANI boosted the capacitance owing to its excellent porosity and fast pseudocapacitive charge storage response.

关键词： Polyaniline Carbon cloth Flexible supercapacitor Flexible electrode Composite

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

Assessment of surface and subsurface waterlogging, water level fluctuations, and lithological variations for evaluating groundwater resources in Ganga Plains

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International Journal of Digital Earth 2013年第3期6卷 276-296页

作者： Arvind chandra Pandey Suraj Kumar singh m.S.Nathawat Dipankar Saha Department of Remote Sensing Birla Institute of TechnologyMesraRanchiIndia Central Ground Water Board Ministry of Water ResourcesPatnaIndia

In the present study,the multi-temporal satellite images of IRS P6 LISS III were used to map waterlogging dynamics over different *** area of 594.36 km2(6.75%)and 4.17 km^(2)(0.04%)was affected by surface waterlogging during pre and postmonsoon season,*** average annual groundwater level fluctuations were calculated using 18 years(1990-2007)pre and postmonsoon groundwater level data to identify the areas which are under groundwater induced waterlogging *** soil map clearly indicates that salinity and sodicity exhibit the highest severity and occur in areas with shallow groundwater *** hydrogeomorphical units mapped using IRS P6 LISS III satellite images are flood plain,alluvial plain,paleochannels,and oxbow *** study revealed that 44.65%areas have very good to excellent groundwater *** litholog data clearly indicate an alternating sequence of clay and sand in which deep aquifers made up of coarse sand would be best suited for adequate water supply and good groundwater *** integrated study utilizing digital spatial data pertaining to waterlogging,soil salinity,water level fluctuation,and lithological variation proved that planning of any surface and subsurface water resources development activity should be taken up after assessments of said parameters.

关键词： waterlogging salinity Ganga plain digital earth groundwater resources digital data

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

FLRW cosmology in metric-affine F(R,Q)gravity

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Chinese Physics C 2024年第12期48卷 158-172页

作者： dinesh chandra maurya K.Yesmakhanova R.myrzakulov G.Nugmanova Centre for Cosmology Astrophysics and Space ScienceGLA UniversityMathura-281406Uttar PradeshIndia Ratbay myrzakulov Eurasian International Centre for Theoretical Physics Nur-Sultan010009Kazakhstan

We investigated some Friedmann-Lemaître-Robertson-Walker(FLRW)cosmological models in the context of metric-affine F(R,Q)gravity,as proposed in[arXiv:1205.5266v6].Here,R and Q are the curvature and nonmetricity scalars using non-special connections,*** obtained the modified field equations using a flat FLRW *** then found a connection between the Hubble constant H_(0),density parameter Ω_(m0),and other model parameters in two different situations involving scalars u and ***,we used new observational datasets,such as the cosmic chronometer(CC)Hubble and Pantheon SNe Ia datasets,to determine the optimal model parameter values through a markov chain monte Carlo(mCmC)*** these best-fit values of the model parameters,we discussed the results and behavior of the derived ***,we discussed the Akaike information criterion(AIC)and Bayesian information criterion(BIC)for the derived models in the context of the Lambda cold dark matter(ΛCDm).We found that the geometrical sector dark equation of state parameter ω_(de)behaves just like a dark energy *** also found that both models are transit phase ***-Ⅰ approaches the ΛCDm model in the late-time universe,whereas model-Ⅱ approaches quintessence scenarios.

关键词： metric-affine F(R,Q)gravity FLRW flat universe FLRW cosmology transit phase expansion observational constraints

Intensified cropping reduces soil erosion and improves rainfall partitioning and soil properties in the marginal land of the Indian Himalayas

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International Soil and Water Conservation Research 2024年第3期12卷 521-533页

作者： Devideen Yadav Deepak singh Subhash Babu madhu madegowda Dharamvir singh Debashis mandal Avinash chandra Rathore Vinod Kumar Sharma Vibha singhal Anita Kumawat dinesh Kumar Yadav Rajendra Kumar Yadav Surender Kumar ICAR-Indian Institute of Soil and Water Conservation DehradunUttarakhand248195India Division of Agronomy ICAR-Indian Agricultural Research InstituteNew Delhi110012India ICAR-Indian Institute of Soil and Water Conservation Research CentreKotaRajasthan324002India ICAR-Indian Institute of Soil Science BhopalMadhya Pradesh462038India Agriculture University KotaRajasthan324001India ICAR-Indian Institute of Soil and Water Conservation Research CentreKoraputOdisha763002India

Environmental crises,land degradation,declining factor productivity,and farm profitability questioned the sustainability of linear economy-based existing agricultural production ***,there is a dire need to design and develop circular economy-based production systems to meet the twin objectives of environmental sustainability and food ***,the productive capacity,natural resource conserving ability,and biomass recycling potential of four intensified maize-based systems ***(Zea mays)+sweet potato(Ipomoea batatas)-wheat,maize+colocasia(Colocasia esculenta)-wheat,maize+turmeric(Curcuma longa),and maize+ginger(Zingiber officinale)were tested consecutively for three years(2020,2021 and 22)in a fixed plot manner at Dehradun region of the Indian Himalaya against the existing maize-wheat *** result showed that the maize+sweet potato-wheat system significantly reduced runoff loss(166.3 mm)over the maize-wheat *** highest through fall(68.12%)and the lowest stem flow(23.54%)were recorded with sole *** the contrary,the maize+sweet potato system has the highest stem flow(36.15%)and the lowest through ***,the maize+sweet potato system had 5.6 times lesser soil erosion and 0.77 t ha^(-1)higher maize pro-ductivity over the maize-wheat ***,the maize+sweet potato system recorded significantly higher soil moisture(19.3%),infiltration rate(0.95 cm h^(-1)),and organic carbon(0.78%)over the rest of the *** maize+sweet potato system also recycled the highest nitrogen(299.2 kg ha^(-1)),phosphorus,(31.0 kg ha^(-1)),and potassium(276.2 kg ha^(-1))into the soil ***,it can be inferred that concurrent cultivation of sweet potato,with maize,is a soil-supportive,resource-conserving,and productive production model and can be recommended for achieving the circular economy targets in the Indian Himalayas.

关键词： Crop productivity Erosion Infiltration Runoff Soil sedimentation

metallurgical Behaviour and Carbon Diffusion in Buttering Deposits Prepared With and Without Buffer Layers

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Acta metallurgica Sinica(English Letters) 2017年第2期30卷 120-132页

作者： dinesh W.Rathod Sunil Pandey Sivanandam Aravindan Pavan Kumar singh Department of mechanical Engineering Indian Institute of Technology Delhi Hauz-Khas New Delhi 110016 India School of mACE University of Manchester Manchester M13 9PL UK Bhabha Atomic Research Centre Mumbai 400085 India

Use of a buttering deposit on ferritic steel in dissimilar metal weld（DmW） joint is a common practice in nuclear plants to connect pressure vessel components（ferritic steel） to pipelines（austenitic stainless steel）.Carbon migration and metallurgical changes near fusion interface（ferritic steel–austenitic stainless steel） lead to a steeper gradient in material properties,and minimizing this gradient is the major challenge in the manufacturing of DmW *** 82 is often deposited on ferritic steel material as buttering to reducing the gradient of physical and attaining material *** 82/182 fillers are used to minimize the carbon migration,but the results are not truly *** this paper,Ni–Fe alloy（chromium-free） has been used as the intermediate buffer layer in the weld buttering deposit to address the issue of carbon migration and subsequent metallurgical *** weld pads with and without buffer layers of Ni–Fe alloy have been investigated and compared in detail for metallurgical properties and carbon ***–Fe buffer layer can significantly control the carbon migration which resists the metallurgical *** showed the better results in postweld heat treatment and thermally aged *** buttering deposit with Ni–Fe buffer layer could be the better choice for DmW joints requirements.

关键词： Dissimilar welds Buttering Carbon diffusion Buffer layer metallurgical properties

Effect of Gd addition on the superconducting properties of Ti-based V, Nb, Ta alloys

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Superconductivity 2023年第2期6卷 58-63页

作者： SK Ramjan LS.Sharath chandra Rashmi singh m.K.Chattopadhyay Free Electron Laser Utilization Laboratory Raja Ramanna Centre for Advanced TechnologyIndore 452013Madhya PradeshIndia Homi Bhabha National Institute Training School ComplexAnushakti NagarMumbai 400094MaharastraIndia Laser and Functional materials Division Raja Ramanna Centre for Advanced TechnologyIndore 452013Madhya PradeshIndia

The critical current density(Jc)of the body centered cubic(bcc)V0.6Ti0.4 alloy enhances significantly after the addition of rare earth Gd as the latter is immiscible in the matrix[***,***,IEEE ***.31,5(2021)].Very low solubility of Gd in other bcc elements like Ta and Nb is also well known[*** Gschneidner in Prog Sci Technol Rare Earths,vol.1,pp.222–258,1964&m Neuberger,*** in Handbook of Electronic materials,Vol 4,1972].We use these facts to find the effect of adding 1 at.%Gd into the Nb0.6Ti0.4 and Ta0.4Ti0.6 alloys on the superconducting properties e.g.,the transition temperature(Tc),Jc,flux pinning force density(Fp)and the *** spite of Gd being ferromagnetic,the Tc in these alloys change only marginally(increase by 0.3 K in Ta0.4Ti0.6 and decrease by 0.15 K in Nb0.6Ti0.4 after Gd *** Jc(H?1 T,T=4 K)increases by 5 and 1.5 times respectively in the Gd containing Nb0.6Ti0.4 and Ta0.4Ti0.6 alloys,which is quite small as compared to the increase observed in the V0.6Ti0.4(20 times)*** Gd addition,the grain size reduces approximately by 65%and 10%respectively in Nb0.6Ti0.4 and *** analysis indicates that grain boundaries are the major flux line pinning centres in these alloys and the role of Gd in increasing the Jc depends on the effectiveness of Gd in reducing the grain *** grain boundary density depends strongly on the distribution of Gd precipitates,which is quite different from each other for two alloy systems under ***,our results suggest that the addition of Gd to commercial Nb‐Ti(Nb0.37Ti0.63)alloy is a new promising route for achieving higher Jc values.

关键词： Critical current density Ferromagnetism Flux pinning Grain boundary