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Acta Geochimica 2020年第3期39卷 365-386页

作者： surendra kumar jha Rashmi Sharma Jaya Prakash Shrivastava University of Delhi DelhiIndia Department of Cement Technology A.K.S.UniversitySatnaMPIndia

Paleoproterozoic Bijawars of the Sonrai basin consists of(a) Sonrai(mostly carbonate carbonaceous shale and phosphatic breccia) and(b) Solda Formations(commonly chloritic and ferruginous shale) with well-developed clay-organo-rich facies,often marked with hydrothermal *** studies revealed abundance order of kaolinite> chlorite> illite> smectite;and kaolinite> illite> chlorite in clay(0.2-2.0 μm) fractions separated from the Sonrai and Solda Formations,*** understand atomic substitutions and trace elemental concentrations,clay minerals were analyzed by fusion ICPMS and *** normalized data plots show U,Th,Rb,Ba,Pb Sr,and large-ion lithophiles enrichment,whereas,Bandai sandstone and Rohini carbonate clays show HREE enrichment with asymmetrical patterns,similar to those reported from the well-established McArthur River,Cigar Lake,and Sue UTUD of *** Rohni carbonate,chondrite-normalized REE data plots revealed M shape REE patterns,ascribed to Gd-Tb-Dy-Ho tetrad effect and anomalous Y,Zr,and Hf *** to HREE incorporation in the clay inter-layers,linear and flattened REE trends were *** REE patterns associated with the highly altered chlorite and illite represent negative Eu anomaly related to the dilational nature of the uraninite structure and is suggestive of anoxic conditions.

关键词： Bijawars Sonrai basin Clays REE patterns Uranium mineralization

Adaptive Linear Quadratic Regulator for Continuous-Time Systems With Uncertain Dynamics

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 833-841页

作者： Sumit kumar jha Shubhendu Bhasin IEEE Department of Electronics and Communication Engineering Motilal Nehru National Institute of Technology AllahabadPrayagraj-211004India Department of Electrical Engineering Indian Institute of Technology DelhiNew Delhi-110016India

In this paper, adaptive linear quadratic regulator(LQR) is proposed for continuous-time systems with uncertain dynamics. The dynamic state-feedback controller uses inputoutput data along the system trajectory to continuously adapt and converge to the optimal controller. The result differs from previous results in that the adaptive optimal controller is designed without the knowledge of the system dynamics and an initial stabilizing policy. Further, the controller is updated continuously using input-output data, as opposed to the commonly used switched/intermittent updates which can potentially lead to stability issues. An online state derivative estimator facilitates the design of a model-free controller. Gradient-based update laws are developed for online estimation of the optimal gain. Uniform exponential stability of the closed-loop system is established using the Lyapunov-based analysis, and a simulation example is provided to validate the theoretical contribution.

关键词： Adaptive optimal control continuous policy update linear quadratic regulator uncertain system dynamics

miR-106b as an emerging therapeutic target in cancer

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Genes & Diseases 2022年第4期9卷 889-899页

作者： surendra kumar Sagar Department of Zoology Swami Shraddhanand CollegeUniversity of DelhiDelhi 110036India

MicroRNAs (miRNAs) comprise short non-coding RNAs that function in regulating the expression of tumor suppressors or oncogenes and modulate oncogenic signaling pathways in cancer. miRNAs expression alters significantly in several tumor tissues and cancer cell lines. For example, miR-106b functions as an oncogene and increases in multiple cancers. The miR-106b directly targets genes involved in tumorigenesis, proliferation, invasion, migration, and metastases. This review has focused on the miR-106b function and its downstream target in different cancers and provide perspective into how miR-106 regulates cancer cell proliferation, migration, invasion, and metastases by regulating the tumor suppressor genes. Since miRNAs-based therapies are currently being developed to enhance cancer therapy outcomes, miR-106b could be an attractive and prospective candidate in different cancer types for detection, diagnosis, and prognosis assessment in the tumor.

关键词： Apoptosis Cancer Metastases miRNA Oncogene Tumor suppressor

Temporal patterns of storage and flux of N and P in young Teak plantations of tropical moist deciduous forest,India

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Journal of Forestry Research 2014年第1期25卷 75-86页

作者： Kaushalendra kumar jha Technical Forestry Indian Institute of Forest Management

Teak （Tectona grandis Linn. f.） ranks among the top five tropical hardwood species and is being promoted for use in plantations in its non-native range due to its high economic value. However, there is a general lack of data on ecosystem functioning of teak plantations. We aimed at understanding storage and flux of nutrients related to young plantations of teak. Cycling of nitrogen （N） and phosphorus （P） in a chronosequence of plantations （1, 5, 11, 18, 24 and 30 years） was studied in the Moist Deciduous Forest Region of North India with the objective of investigating the nutrient cycling pattern at younger age since the current trend of harvesting age of the species in several tropical countries is being drastically reduced for quick return from this high value crop. Standing state, nutrient uptake, nutrient return and nutrient retransloca-tion in these plantations were estimated by tree harvesting and chemical analysis methods. The range of total standing nutrient across all these plantations was 20.3 to 586.6 kg？ha-1 for N and 5.3 to 208.8 kg？ha-1 for P. Net uptake of N ranged from 19.4 to 88.9 kg？ha-1？a-1 and P from 3.8 to 18.1 kg？ha-1？a-1. Retranslocation of N and P among all the stands ranged from 8.7 to 48.0 kg？ha-1？a-1 and 0.01 to 3.5 kg？ha-1？a-1, respectively. Range of total nutrient return was 25.8 to 91.3 kg？ha-1？a-1 for N and 2.7 to 10.1 kg？ha-1？a-1 for P. N and P use efficiency was between 107.4 and 192.5 g dry organic matter （OM） g-1N, and 551.9 and 841.1 g OM g-1P, respec-tively. The turnover time ranged from 2.04-13.17 years for N and be-tween 2.40-22.66 years for P. Quantity of N and P in the soil nutrient pool ranged from 2566.8 to 4426.8 kg？ha-1 and 372 to 520 kg？ha-1, re-spectively. Storage and flux of components in different plant parts of different aged plantations were assessed and depicted in compartment models. Percentage storage in soil, litter and vegetation ranged from 82% to 99%, 0.6% to 2.4% and 0.5% to 15% for N, respectively, and from

关键词： nutrient uptake standing state return turnover time nutrient use efficiency compartment model harvest loss Tectona grandis

Biomass production and carbon balance in two hybrid poplar(Populus euramericana)plantations raised with and without agriculture in southern France

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Journal of Forestry Research 2018年第6期29卷 1689-1701页

作者： Kaushalendra kumar jha UMR Systems Institute Nationale de la Recherche Agronomique2 place Pierre Viala34060 MontpellierFrance Technical Forestry Indian Institute of Forest ManagementBhopalIndia

Poplar is useful in different climates for bioenergy production and carbon sequestration when planted as a single species or in agroforestry. Europe has large areas potentially suitable for poplar forestry and a bioenergy policy that would encourage poplar forestry. In this study I estimated biomass production and carbon sequestration in poplar monoculture plantation and poplar-wheat agroforestry, in the Mediterranean region of France. A single-tree harvesting method was used to estimate biomass and an empirical conversion factor was adopted to calculate sequestered carbon. Total biomass was higher in agroforestry trees(1223 kg tree) than in monoculture plantation trees(1102 kg tree).Aboveground and belowground biomass distributions were similar in both cases(89 and 88% aboveground, and 11 and12% belowground, respectively in agroforestry and monoculture). The partitioning of total biomass in an agroforestry tree in leaves, branch, and trunk(aboveground), and fine roots, medium roots, coarse roots and underground stem(belowground) was 1,22,and 77,and 6,9, 44 and 40%,respectively. Except for branch and trunk, all other compartments were similarly distributed in a monoculture *** of C was higher in agroforestry trees(612 kg tree)than in monoculture trees(512 kg tree). In contrast, C storage on a per hectare basis was lower in agroforestry(85 Mg ha) than in monoculture(105 Mg ha) due to the lower density of trees per hectare in agroforestry(139 trees in agroforestry vs 204 trees in monoculture). On a per hectare basis, soil C stocks pattern were similar to per tree stocking:They were higher in agroforestry at 330 Mg hathan in monoculture 304 Mg ha. Higher C accumulation by agroforestry has a direct management implication in the sense that expanding agroforestry into agriculture production areas with short rotation and fast growing trees like poplar would encourage quicker and greater C sequestration. This could simultaneously fulfil the requirement of bioenergy

关键词： Populus euramericana Wood volume and density Root:shoot ratio Vegetation and soil carbon System efficiency

Carbon storage and sequestration rate assessment and allometric model development in young teak plantations of tropical moist deciduous forest, India

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Journal of Forestry Research 2015年第3期26卷 589-604页

作者： Kaushalendra kumar jha Technical Forestry Indian Institute of Forest ManagementPO Box No. 357 Nehru Nagar Bhopal 462 003 MP India

Carbon （C） sequestration through plantations is one of the important mitigation measures for rising levels of carbon dioxide and other greenhouse gases in the atmosphere. This study aimed to assess C stocks and their sequestration rate, and to develop allometric models for estimation of C stocking in age-series young teak （Tectona grandis） planta- tions （1, 5, 11, 18, 24 and 30 years） by using biomass and productivity estimation and regression, respectively. These plantations were raised in tropical moist deciduous forests of Kumaun Himalayan tarai. Total C stocks estimated for these plantations were 1.6, 15.8, 35.4, 39.0, 61.5 and 73.2 Mg ha-1, respectively. Aboveground and belowground C storage in- creased with increasing plantation age; however, the range of their percentage contribution showed little variation （87.8-88.2 and 11.7-12.7 %, respectively）, The rate of C sequestration for these respective plantations was 1.06, 6.95, 5.46, 5.42, 3.39 and 5.37 Mg ha-1 a-1. Forty percent of the aboveground annual storage was retained in the tree while 60 % was released in the form of foliage, twigs, and fruit litter. In the case of total （tree） annual production, 43 % was retained while 57 % was released as litter including root. C stock, C sequestration rate, accumulation ratio （1.4-18.1）, root：shoot C ratio （0.61--0.13） and production efficiency （0.01-0.18） were comparable to some previous reports for other species and forests. These data could be useful in deciding the harvesting age for young teak with respect to C storage and sequestrationrate. Four allometric models using linear regression equations were developed between biomass （twice the C stock） and diameter, girth, and height of the tree at different ages. The diameter model was found more suitable for C stock predic- tion in similar areas.

关键词： Age series Biomass Carbon budget DBH Productivity Production ratios Regression equations -Tectona grandis

Pedotransfer Functions for Estimating Soil Hydraulic Properties： A Review

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Pedosphere 2016年第4期26卷 417-430页

作者： Nitin Gorakh PATIL surendra kumar SINGH National Bureau of Soil Survey and Land Use Planning Shankaruagar P.O.Amravati RoadNagpur 440010 India

Characterization of soil hydraulic properties is important to environment management; however, it is well recognized that it is laborious, time-consuming and expensive to directly measure soil hydraulic properties. This paper reviews the development of pedotransfer functions （PTFs） used as an alternative tool to estimate soil hydraulic properties during the last two decades. Modern soil survey techniques like satellite imagery/remote sensing has been used in developing PTFs. Compared to mechanistic approaches, empirical relationships between physical properties and hydraulic properties have received wide preference for predicting soil hydraulic properties. Many PTFs based on different parametric functions can be found in the literature. A number of researchers have pursued a universal function that can describe water retention characteristics of all types of soils, but no single function can be termed generic though van Cenuchten （VG） function has been the most widely adopted. Most of the reported parametric PTFs focus on estimation of VG parameters to obtain water retention curve （WRC）. A number of physical, morphological and chemical properties have been used as predictor variables in PTFs. Conventionally, regression algorithms/techniques （statistical/neurM regression） have been used for calibrating PTFs. However, there are reports of utilizing data mining techniques, e.g., pattern recognition and genetic algorithm. It is inferred that it is critical to refine the data used for calibration to improve the accuracy and reliability of the PTFs. Many statistical indices, including root mean square error （RMSE）, index of agreement （d）, maximum absolute error （ME）, mean absolute error （MAE）, coefficient of determination （r2） and correlation coefficient （r）, have been used by different researchers to evaluate and validate PTFs. It is argued that being location specific, research interest in PTFs will continue till generic PTFs are developed and validated. In future studi

关键词： database generic PTF hydraulic conductivity predictor properties PTF development tools regression statistical indices water retention curve

Thermodynamic behaviour of Rashba quantum dot in the presence of magnetic field

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Chinese Physics B 2016年第5期25卷 262-267页

作者： Sukirti Gumber Manoj kumar Pradip kumar jha Man Mohan Department of Physics & Astrophysics University of Delhi Department of Physics DDU College University of Delhi

The thermodynamic properties of an In Sb quantum dot have been investigated in the presence of Rashba spin–orbit interaction and a static magnetic field. The energy spectrum and wave-functions for the system are obtained by solving the Schrodinger wave-equation analytically. These energy levels are employed to calculate the specific heat, entropy,magnetization and susceptibility of the quantum dot system using canonical formalism. It is observed that the system is susceptible to maximum heat absorption at a particular value of magnetic field which depends on the Rashba coupling parameter as well as the temperature. The variation of specific heat shows a Schottky-like anomaly in the low temperature limit and rapidly converges to the value of 2kB with the further increase in temperature. The entropy of the quantum dot is found to be inversely proportional to the magnetic field but has a direct variation with temperature. The substantial effect of Rashba spin–orbit interaction on the magnetic properties of quantum dot is observed at low values of magnetic field and temperature.

关键词： quantum dot Rashba spin–orbit interaction thermal and magnetic properties

An exponential expanding meshes sequence and finite difference method adopted for two-dimensional elliptic equations

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International Journal of Modeling, Simulation, and Scientific Computing 2016年第2期7卷 109-125页

作者： Navnit jha Neelesh kumar Faculty of Mathematics and Computer Science Department of Mathematics South Asian University ChanakyapuriNew Delhi 110021India

We demonstrate a new nonuniform mesh finite difference method to obtain accurate solutions for the elliptic partial differential equations in two dimensions with nonlinear first-order partial derivative *** method will be based on a geometric grid network area and included among the most stable differencing scheme in which the nine-point spatial finite differences are implemented,thus arriving at a compact *** general,a third order of accuracy has been achieved and a fourth-order truncation error in the solution values will follow as a particular *** efficiency of using geometric mesh ratio parameter has been shown with the help of *** convergence of the scheme has been established using the matrix analysis,and irreducibility is proved with the help of strongly connected characteristics of the iteration *** difference scheme has been applied to test convection diffusion equation,steady state Burger’s equation,ocean model and a semi-linear elliptic *** computational results confirm the theoretical order and accuracy of the method.

关键词： Geometric mesh finite difference compact method elliptic partial differential equations convection diffusion equation Stommel ocean model

Numerical investigation of the effect of transitory strand opening on mixing in a multistrand tundish

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International Journal of Minerals,Metallurgy and Materials 2011年第5期18卷 535-542页

作者： Sabin kumar Mishra Pradeep kumar jha Satish Chandra Sharma Satish kumar Ajmani Department of Mechanical and Industrial Engineering Indian Institute of Technology RoorkeeRoorkee 247667UttarakhandIndia Steelmaking and Casting Research Group Tata SteelR&DBurma MinesJamshedpur 831007JharkhandIndia

In a multistrand,the outlet near the inlet produces short circuiting *** leads to the formation of dead zones inside the tundish,and consequently,the mean residence time *** the present study,numerical investigation of mixing inside a delta shaped tundish with sloping boundaries was carried out by solving the Navier-Stokes equation and employing the standard turbulence *** decrease the dead zone volume inside the tundish,the effect of closing the outlet near the inlet for a small amount of time and further opening it on the mixing behavior of the tundish was *** outlets near the inlet were closed for varying amount of time,and the transient analysis of fluid flow and the tracer dispersion study were carried out to find the mixing parameters of the tundish,namely,mean residence time and the ratio of mixed to dead volume of the *** optimum closure time of the near outlet has been found,which yields best mixing inside the *** numerical code was validated against the experimental observation by performing the tracer dispersion study inside a multistrand tundish and the reasonably good match between the experimental and numerical results in terms of residence time distribution （RTD） *** results obtained from the present study confirm the strong role of choosing the right time for opening and closing the outlets to get improved characteristics for the fluid flow and mixing behavior of the *** educational version of computational fluid dynamics （CFD） software PHOENICS was used to solve the governing equations and interpret the results in different forms.

关键词： continuous casting billets tundish flow simulation mean residence time dead volume computational fluid dynamics (CFD)