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Long-term fertilizer nitrogen management—Soil health conundrum

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Pedosphere 2024年第1期34卷 23-25页

作者： BIJAY-singh Department of Soil Science Punjab Agricultural UniversityLudhiana 141004India

The mental model that fertilizer nitrogen (N) acts as a replacement for N mineralized from soil organic matter (SOM) needs to be revisited. Soil organic matter, the storehouse of N in soil, is one of the most important indicators of soil health. It supplies more N to crop plants than the current-year fertilizer N even when applied at high rates. Limited research shows that the application of fertilizer N above the optimum levels on a long-term basis deteriorates soil health by mineralizing SOM and depleting the soil N pool. Because soil N includes portions of fertilizer N applied in several previous years, year after year application of fertilizer N below the optimum levels will also lead to a gradual decline in soil N pool or soil health. To sustain high crop yield levels, fertilizer N needs to be applied on a long-term basis neither above nor below the optimum levels to ensure that soil health in terms of sustaining supply of soil N is maintained, if not enhanced.

关键词： soil Soil optimum

Geochronological and genetic characterization of basaltic basement from western offshore basins in India

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Geoscience Frontiers 2024年第5期15卷 372-398页

作者： Piyush Gupta Shakti singh Rathore Sandeep singh Geochronology Laboratory KDMIPEOil and Natural Gas Corporation Ltd.9Kaulagarh RoadDehradun 248195India Department of Earth Sciences Indian Institute of TechnologyRoorkee 247667India

^(40)Ar-^(39)Ar geochronology,geochemistry,and Sr-Nd isotopic compositions of 30 core samples from 24 offshore drill wells in the Western offshore basins have been used to characterize the genetics of the volcanic basement from the Kutch,Mumbai,and Kerala-Konkan offshore *** from the volcanic basement rocks demonstrate extremely varied isotopic and geochemical fingerprints,which are suggestive of significantly diverse parent magma compositions and emplacement *** tholeiitic basement from Kutch Offshore basin has Ar-Ar ages that range between 60 Ma and 62 *** basement is characterised by a within-plate basalt signature,with depleted isotopic signatures similar to least contaminated Deccan Traps basalts,and a component of subducted crustal *** basement from Mumbai Offshore Basin has eruption ages between 63 Ma and 65 Ma and show a strong within-plate OIB *** and isotopic signatures are consistent with Renuion lavas and an enriched-end member of Deccan Traps ***,Kerala-Konkan Offshore Basin shows significant E-MORB affinity and is characterized by primitive-mantle signatures and least contamination from the upper continental crust,with ages of eruption between 60 Ma and 61 Ma based on obtained^(40)Ar-^(39)Ar *** study suggests that the Mumbai Offshore Basalts’mode of the eruption was comparable with onshore Deccan volcanism,whereas the basaltic basement in Kutch Offshore was formed after the main phase of Deccan eruption and may have been an offshoot of a"tail"of the main Deccan *** parent magma for the volcanic E-MORB basement in the Kerala-Konkan Offshore Basin is thought to have come from mixing along the Carlsberg Mid-Oceanic Ridge and the material from the Réunion plume with the northward movement of the Indian Plate during the Early *** is thought to have occurred concurrently with the formation of the Chagos-Laccadive Ridge.

关键词： ^(40)Ar-^(39)Ar geochronology Western offshore basins Kutch offshore basin Mumbai offshore basin Kerala-Konkan offshore basin

Investigation of structural, morphological and electrochemical properties of mesoporous La2CuCoO6 rods fabricated by facile hydrothermal route

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International Journal of Minerals,Metallurgy and Materials 2020年第7期27卷 987-995页

作者： Jashandeep singh Ashok Kumar Department of Physics National Institute of Technology KurukhsetraHaryana 136119India Department of Applied Sciences National Institute of Technical Teachers Training and ResearchChandigarh 160019India

This work introduces the facile hydrothermal synthesis of double perovskite La2CuCoO6.X-ray diffraction pattern confirmed the formation of a monoclinic phase with P121/c1 *** electron microscopy results revealed that the self-assembled porous rods were composed of nanocrystallite *** estimated specific surface area of these mesoporous rods with an average pore diameter of 6 nm was^41 m^2·g^–*** presence of ions with oxidation states of La^3+,Cu^2+,and Co^2+/Co^3+on the surface of the mesoporous La2CuCoO6 rods was confirmed by X-ray photoelectron spectroscopic *** cyclicvoltammetry and chronopotentiometry,the electrode fabricated from the mesoporous La2CuCoO6 rods were found to exhibit pseudocapacitive behavior with a specific capacitance of 259.4 F·g^–1 at a current density of 0.5 A·g^–***^89%retention in specific capacitance was achieved after 1000 charge/discharge cycles at a constant current density of4 A·g^–1.

关键词： rare earth double perovskites oxide materials hydrothermal electrochemical

Properties of Ternary One Dimensional Plasma Photomic Crystals for an Obliquely Incident Electromagnetic Wave Considering the Effect of Collisions in Plasma Layers

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Plasma Science and Technology 2012年第12期14卷 1084-1090页

作者： S. PRASAD Vivek singh A. K. singh Department of Physics Faculty of ScienceBanaras Hindu University

An analytical study is presented on the modal dispersion characteristics, group velocity, and effective group, as well as the phase index of a ternary one dimensional plasma photonic crystal for an obliquely incident electromagnetic wave considering the effect of collisions in plasma layers. The dispersion relation is derived by using the transfer matrix method and the boundary conditions based on electromagnetic theory. The dispersion curves are plotted for both the normal photonic band gap structure and the absorption photonic band gap structure. It is found that the increase in the angle of incidence shifts the photonic band gap toward higher frequencies. Also, the cutoff frequency is independent of collisions.

关键词： ternary plasma photonic crystal dispersion curves group and phase velocities,obliquely incident collision effect

Indian summer monsoon rainfall (ISMR) forecasting using time series data: A fuzzy-entropy-neuro based expert system

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Geoscience Frontiers 2018年第4期9卷 1243-1257页

作者： Pritpal singh Smt. Chandaben Mohanbhai Patel Institute of Computer Applications CHARUSAT Campus

This study presents a model to forecast the Indian summer monsoon rainfall（ISMR）（June-September）based on monthly and seasonal time scales. The ISMR time series data sets are classified into two parts for modeling purposes, viz.,（1） training data set（1871-1960）, and（2） testing data set（1961-2014）.Statistical analyzes reflect the dynamic nature of the ISMR, which couldn＇t be predicted efficiently by statistical and mathematical based models. Therefore, this study suggests the usage of three techniques,viz., fuzzy set, entropy and artificial neural network（ANN）. Based on these techniques, a novel ISMR time series forecasting model is designed to deal with the dynamic nature of the ISMR. This model is verified and validated with training and testing data sets. Various statistical analyzes and comparison studies demonstrate the effectiveness of the proposed model.

关键词： Indian summer monsoon rainfall(ISMR) Fuzzy set Entropy Artificial neural network(ANN) Forecasting

Protracted zircon growth in migmatites and In situ melt of Higher Himalayan Crystallines:U-Pb ages from Bhagirathi valley, NW Himalaya,India

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Geoscience Frontiers 2019年第3期10卷 793-809页

作者： Sandeep singh Department of Earth Sciences Indian Institute of Technology Roorkee

The Higher Himalayan Crystallines(HHC), in western Garhwal, Uttarakhand are located in a regionalscale intracontinental ductile shear zone(15-20 km wide) bounded by the Main Central Thrust at the base, and the South Tibetan Detachment System at the top. The migmatite zone in the centre has the highest grade of metamorphism in the NW Himalayas and show evidence of flowage. Zircons extracted from samples of metasediment, migmatite, biotite granite and in situ partial melt(tourmaline-bearing leucogranite) along the Bhagirathi Valley, preserve U-Pb isotopic evidence of magmatic history, magma source and effects of the Himalayan orogeny in the region. Three distinct periods of zircon growth in the leucogranite record the episodic influx of magma between 46 Ma and 20 Ma indicating a time span of more than 25 Ma between the onset of fluid-fluxed partial melting in the mid-crustal intracontinental shear zone and the emplacement of the magma into the upper crust in a post-collisional extensional setting. Metamorphic zircon growth was initiated about 46 Ma, when the partial melts were generated as the migmatite zone was exhumed.

关键词： Himalayas Crustal anatexis Zircon SHRIMP U-Pb dating Migmatites Granites

Impact of surface Albedo on Martian photochemistry

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Earth and Planetary Physics 2020年第3期4卷 206-211页

作者： Deepak singh Physical Research Laboratory AhmedabadIndia

Solar energy is the primary driving force behind a planet’s climate system,and surface albedo plays a key role in determining the energy budget of the *** the Snow,Ice,and Aerosol Radiation(SNICAR)with the Laboratoire de Météorologie Dynamique(LMD)Mars General Circulation Model(MGCM)to create a new coupled model leads to an approximately 4%drop in the net CO2 ice deposition on *** simulated surface albedo affects the concentration of gaseous species in the Martian atmosphere(condensation-sublimation cycle).The new set-up also impacts the solar energy available in the *** two effects together lead to subsequent and significant changes in other chemical species in the Martian *** with results of the MGCM model alone,in the new coupled model CO2(gas)and O3 show a drop of about 1.17%and 8.59%in their respective concentrations,while H2O(vapor)and CO show an increase of about 13.63%and 0.56%in their respective *** trace species,OH shows a maximum increase of about 29.44%,while the maximum drop of 11.5%is observed in the O *** neutral species such as Ar and N2 remain unaffected by the albedo changes.

关键词： Mars Albedo snow photochemistry climate modelling

Representative Elementary Volume(REV) in Spatio-Temporal Domain： A Method to Find REVfor Dynamic Pores

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Journal of Earth Science 2017年第2期28卷 391-403页

作者： Harpreet singh The University of Texas at Austin Austin TX USA National Energy Technology Laboratory Morgantown WV USA

One of the potential risks associated with subsurface storage of CO_2 is the seepage of CO_2 through existing faults and fractures. There have been a number of studies devoted to this topic. Some of these studies show that geochemistry, especially mineralization, plays an important role in rendering the faults as conduits for CO_2 movement while others show that mineralization due to CO_2 injection can result in seep migration and flow diversion. Therefore, understanding the changes in reservoir properties due to pore alterations is important to ensure safe long term CO_2 storage in the subsurface. We study the changes in the Representative Elementary Volume（REV） of a rock due to reactive kinetics over a time, using a statistical approach and pore-scale CO_2-rock *** goal of this study is to obtain the REV of a rock property that accounts for pore-scale changes over time due to reactive kinetics, and we call this as spatiotemporal REV. Scale-up results suggest that the REV changes with time when CO_2-rock interaction is considered. It is hypothesized that the alteration in pore structure introduces more heterogeneity in the rock, and because of this the magnitude of REV increases. It is possible that these noticeable changes in REV at pore-scale may have an impact when analyzed at the reservoir scale.

关键词： reactive dynamics reaction rate constant CO_2 scale-up upscaling geostatistics

Bearing capacity of foundations on rock slopes intersected by non-persistent discontinuity

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International Journal of Mining Science and Technology 2020年第5期30卷 669-674页

作者： Divya Shaunik Mahendra singh Department of Civil Engineering Indian Institute of Technology RoorkeeRoorkee 247667India

Rocks encountered in foundations of heavy structures are invariably intersected by discontinuities(joints).In the past,several studies have been performed by researchers to incorporate the effect of fully persistent joints in the assessment of the load-carrying capacity of ***,in the field,the joints are non-persistent,and an assumption of full persistency will underestimate the ***,Shaunik&singh have studied the influence of non-persistency,number of joint segments and discontinuity orientation on the strength behaviour of rock specimens(Shaunik and singh,2019).Bell’s approach can be used to obtain the bearing capacity of shallow foundations placed in jointed *** the present study,results of the experimental work(Shaunik and singh,2019)conducted by Shaunik&singh have been used to suggest expressions by extending Bell’s approach for computing bearing capacity of the foundation placed near the crown of a rock *** to use design charts are also presented for field ***,a real-life problem from Indian Garhwal Himalayas is considered,and the approach suggested in this study is utilised to obtain the bearing capacity of a bridge foundation as a function of uniaxial compressive strength(UCS)of intact rock,joint friction,spacing and orientation of joint,nonpersistency and number of joint segments.

关键词： Uniaxial compressive strength(UCS) Joint segment Discontinuity Non-persistency Bell’s approach