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Mechanical performance of rock bolts under combined load conditions

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International journal of Mining science and Technology 2020年第2期30卷 167-177页

作者： P.C.Pinazzi A.j.s.(sam)spearing K.V.jessu P.singh R.Hawker Department of Mining and Metallurgical Engineering Western Australian School of MinesCurtin UniversityKalgoorlieWA 6430Australia Minova Global NowraNSW 2541Australia

Rock bolts are subjected to different loading conditions along their lengths such as axial,bending,and/or shear forces,which can cause failure at lower loads than those considered for design *** common existing methodologies do not consider the actual loading of the rock bolts and assume it is only pure axial or pure *** study was conducted to investigate the un-grouted rock bolt performance under combined load *** loading regimes were evaluated:the effect of initial shear displacement on axial load capacity and displacement,and the effect of axial displacement on the shear load *** first regime was also conducted for shear with a gap,when there is a spacing between the shear *** results of this study showed that the rock bolt can resist higher axial loads than shear under pure or combined load *** combined load conditions,the rock bolt capacity decreased significantly for both ***,when applying the shear load with a gap,the rock bolt load capacity was not affected ***,the total bar deformation was improved for shear and *** findings of this study show the need to improve the rock bolt design considering the complex loading conditions in situ with/without a gap.

关键词： Rock bolt Combined load Gap test Failure mechanism Axial load shear load

Discovery and preclinical development of ⅢM-160, a Bergenia ciliatabased anti-inflammatory and anti-arthritic botanical drug candidate

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journal of Integrative Medicine 2019年第3期17卷 192-204页

作者： sandip B.Bharate Vikas Kumar sonali s.Bharate Bikarma singh Gurdarshan singh Amarinder singh Mehak Gupta Deepika singh Ajay Kumar surjeet singh Ram A.Vishwakarma Medicinal Chemistry Division Indian Institute of Integrative Medicine Council of Scientific and Industrial Research PK-PD Toxicology & Formulation Division Indian Institute of Integrative Medicine Council of Scientific and Industrial Research Biodiversity and Applied Botany Division Indian Institute of Integrative Medicine Council of Scientific and Industrial Research Quality Control and Quality Assurance Division Indian Institute of Integrative Medicine Council of Scientific and Industrial Research

Objective: Bergenia ciliata(Haw.) sternb. is used in the Indian traditional system of medicine to treat various ailments including rheumatism and to heal wounds. The objective of the present study was to perform a preclinical characterization of the B. ciliata-based botanical extract ***: ⅢM-160 was chemically standardized and analyzed for heavy metal content, aflatoxins,pesticides and microbial load. The in vitro and in vivo efficacies were determined in suitable models of inflammation, arthritis and nociception. An acute oral toxicity study was performed in swiss albino mice.A suitable oral formulation was developed and ***: Bergenin was found to be the major component(9.1% w/w) of ⅢM-160. The botanical lead displayed inhibition of lipopolysaccharide-induced production of proinflammatory cytokines in THP-1 cells, with selectivity toward interleukin-6(IL-6) and had an excellent safety-window. It showed anti-inflammatory, anti-arthritic and antinociceptive activity in animal models and was not toxic at oral doses up to 2 g/kg in swiss-albino mice. The gastroretentive, sustained-release capsule formulation showed sustained-release of the bergenin over the period of 24 h, resulting in improved plasma-exposure of bergenin in sprague–Dawley ***: The dual-activity of IL-6 inhibition and antinociception marks the suitability of ⅢM-160 for treating rheumatoid arthritis. This study will serve as the benchmark for further research on this botanical formulation.

关键词： Botanical preclinical candidate UIM-160 Bergenia ciliata Arthritis Gastroretentive sustained release formulation Bergenin

search for potential K ion battery cathodes by first principles

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journal of Energy Chemistry 2021年第3期30卷 377-385页

作者： Kaining Li Xiaofeng Fan David j.singh WTZheng Key Laboratory of Automobile Materials(jilin University) Ministry of Educationand College of Materials Science and EngineeringJilin UniversityChangchun 130012JilinChina Department of Physics and Astronomy University of MissouriColumbiaMO 65211-7010USA Department of Chemistry University of MissouriColumbiaMO 65211USA state Key Laboratory of Automotive simulation and Control Jilin UniversityChangchun 130012JilinChina

An important challenge facing K-ion batteries lies in exploring earth-abundant and safe cathode materials that can provide high capacity with high migration rate of K ***,we propose a simple and efficient method for searching potential K cathode materials with first principles *** screening is based on combinations of weight capacity,K ion occupation ratio,volume change per K,and valence *** this screening method we predicted a series of potential K ions cathodes with favorable electrochemical performance,such as K_(2)VPO_(4)CO_(3)-like structures with 1 D diffusion channels,3 D channel structures K_(2)CosiO_(4),layered materials KCoO_(2),KCrO_(2),KVF_(4) and K_(5)V_(3)F_(14),and *** potential cathodes have small volume changes,suitable voltage,and high capacity,with small diffusion *** may be useful in K-ion batteries with high energy density and rate performance.

关键词： K ion battery Cathodes First principles calculations High capacity with high migration rate Diffusion barriers

Enhancement of second- and Third-Order Nonlinear Optical susceptibilities in Magnetized semiconductors

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Chinese Physics Letters 2008年第9期25卷 3276-3279页

作者： M. singh P. Aghamkar s. Duhan Department of Applied sciences P.D.M. College of Engineering Bahadurgarh-124507 India Department of Applied Physics G.J. University of Science and Technology Hisar-125001 India Department of Physics Chaudhary Devi Lal University Sirsa-125055 India

Using electromagnetic treatment, an expression of effective nonlinear optical susceptibility χe [= χe^（2）＋ χe^（3） E] is obtained for Ⅲ-Ⅴ semiconducting crystals in an applied transverse dc magnetic fieM under off-resonant transition regime. The origin of nonlinear interaction lies in nonlinear polarization arising from the crystal properties such as piezoelectricity and electrostriction. Numerical estimates have been made by a representative n-Insb crystal at 77K duly irradiated by a pulsed 10.6-μm CO2 laser under off-resonant transition regime. Efforts are dedicated to optimizing doping level and externally applied dc magnetic field to achieve maximum χe^（2） and χ3^（3）. The results are found to be in good agreement with the available literature. The analysis shows that χe^（2） and χe^（3） can be significantly enhanced in doped Ⅲ-Ⅴ semiconductors by the proper selection of doping concentration and dc magnetic field, which confirms its potential as a candidate material for the fabrication of nonlinear optical devices.

关键词： the power-law exponents precipitation durative abrupt precipitation change

spectroscopic investigations and luminescence spectra of sm3+ doped soda lime silicate glasses

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journal of Rare Earths 2009年第5期27卷 773-780页

作者： Y.K. sharma s.s.L. surana R.K. singh Department of Physics Govt. Post Graduate College Rudrapur 263153 (U S Nagar) India Department of Physics J. N. V. University Jodhpur-342001 India Department of Physics Govt. Post Graduate College Rudrapur 263153 (U S Nagar) India

sm3+ doped soda lime silicate glasses co-doped with As2O3 were prepared and characterised by measuring their absorption spectra in UV-VIs/NIR regions and luminescence spectra in the visible region. judd-Ofelt intensity parameters, Ωλ, were evaluated from the measured intensities of the various absorption bands. Ωλ parameters of these glasses were compared with the Ωλ parameters of other reported sm3+ glasses to study the bonding environment surrounding the sm3+ in the present glasses. Presence of [AsO4]3– tetrahedra in the second coordination sphere around the central sm3+ ion made these glasses less covalent as compared to other oxide glasses but the ratio Ω4/Ω6 of the 1.83 indicated them to be fairly stable. With the help of Ωλ parameters and luminescence data for various emission lines, radiative properties for different emission lines were calculated. The values of radiative properties indicated that 4G5/2→6H7/2 and 4G5/2→6H9/2 transitions responsible for orange luminescence might be used in the development of materials for LED's and other optical devices in the visible region.

关键词： rare earth glasses judd-Ofelt theory absorption spectroscopy luminescence

Demineralization of Gondwana coal with Pseudomonas mendocina strain B6-1： a case study of coal from Gopinathpur top and bottom seams of Mugma mine, Dhanbad, jharkhand （India）

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International journal of Coal science & Technology 2016年第2期3卷 235-245页

作者： Prakash K. singh Asha Lata singh Mahendra P. singh A. s. Naik Dharmshila singh spardha Rai Aniruddha Kumar Coal & Organic Petrology Lab Centre of Advanced Study inGeology Banaras Hindu University Varanasi 221005 India Bioremediation Lab Environmental Science Department ofBotany Banaras Hindu University Varanasi 221005 India

In the present investigation an attempt has been made to demineralize the Gondwana coal of Gopinathpur top and bottom seams of Mugma mine, Raniganj coalfield, Dhanbad with the help of Pseudomonas mendocina strain B6-1. The change in the amount of ash yield and decrease in the concentration of selected minor elements like Na, K, Mn and Ca and environmentally sensitive selected trace elements such as Cd, Pb, se, Ni, Mn, and Zn have been studied as a function of time of bacterial treatment as well as with variation in the bacterial biomass. After 28 days of bacterial treatment there was variable amount of decrease observed in ash yield as well as in the concentration of minor and trace elements. The removal of the elements was further enhanced with the increase in the bacterial biomass from 10 to 25 mg/mL. Due to over exploitation of superior grade coals in the country, the remaining coal resources, available for current use, are inferior in grade and contain high level of impurities and there is ample scope of bio-beneficiation of these coals using bacterial biomass.

关键词： Pseudomonas mendocina Gondwana coal Minor and trace elements Demineralization

MHD free convective flow past semi-infinite vertical permeable wall

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Applied Mathematics and Mechanics(English Edition) 2012年第9期33卷 1207-1222页

作者： R.K.singh A.K.singh Department of Mathematics Banaras Hindu University

In this paper, the basic equations governing the flow and heat transfer of an incompressible viscous and electrically conducting fluid past a semi-infinite vertical per- meable plate in the form of partial differential equations are reduced to a set of non-linear ordinary differential equations by applying a suitable similarity transformation. Approx- imate solutions of the transformed equations are obtained by employing the perturbation method for two cases, i.e., small and large values of the suction parameter. From the numerical evaluations of the solution, it can be seen that the velocity field at any point decreases as the values of the magnetic and suction parameters increase. The effect of the magnetic parameter is to increase the thermM boundary layer. It is also found that the velocity and temperature fields decrease with the increase in the sink parameter.

关键词： magnetohydrodynamics (MHD) suction source/sink Prandtl number permeability boundary layer

Frameworks of Non-Orthogonal Multiple Access Techniques in Cognitive Radio Communication systems

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China Communications 2019年第6期16卷 129-149页

作者： Prabhat Thakur Alok Kumar s Pandit G singh s N satashia Department of Electronics and Communication Engineering Jaypee University of Information TechnologyWaknaghat-173215India Department of Electrical and Electronics Engineering Auckland Park Kingsway Campus University of JohannesburgPO Box 524Johannesburg-2006S Africa space Application Centre Indian Space Research OrganizationAhmedabad-380015India

Recently,the increasing demand of radio spectrum for the next generation communication systems due to the explosive growth of applications appetite for bandwidths has led to the problem of spectrum *** potential approaches among the proposed solutions to resolve this issue are well explored cognitive radio(CR)technology and recently introduced non-orthogonal multiple access(NOMA)*** the techniques are employed for efficient spectrum utilization and assure the significant improvement in the spectral ***,the significant improvement in spectral efficiency can be achieved by combining both the *** the CR is well-explored technique as compared to that of the NOMA in the field of communication,therefore it is worth and wise to implement this technique over the *** this article,we have presented the frameworks of NOMA implementation over CR as well as the feasibility of proposed ***,the differences between proposed CR-NOMA and conventional CR frameworks are ***,the potential issues regarding the implementation of CR-NOMA are explored.

关键词： cognitive radio channel state information non-orthogonal multiple access power division multiple access superposition-coding successive-interference-cancellation

Enhanced cavitation erosion resistance of a friction stir processed high entropy alloy

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International journal of Minerals,Metallurgy and Materials 2020年第10期27卷 1353-1362页

作者： Rakesh B.Nair H.s.Arora Harpreet singh Grewal surface science and Tribology Lab Department of Mechanical EngineeringShiv Nadar UniversityGautam Buddha NagarUttar Pradesh 203207India

Friction stir processing of an Al0.1CoCrFeNi high entropy alloy(HEA)was performed at controlled cooling conditions(ambient and liquid submerged).Microstructural and mechanical characterization of the processed and as-cast HEAs was evaluated using electron backscatter diffraction,micro-hardness testing and *** under the submerged cooling condition showed elongated grains(10μm)with fine equiaxed grains(2μm)along the boundary compared to the coarser grain(~2 mm)of as-cast *** hardness showed remarkable improvements with four(submerged cooling condition)and three(ambient cooling condition)times that of as-cast HEA(HV^150).The enhanced hardness is attributed to the significant grain refinement in the processed *** erosion behavior was observed for samples using an ultrasonication *** of the HEAs showed better cavitation erosion resistance than the stainless steel *** sample processed under a submerged liquid condition showed approximately 20 and 2 times greater erosion resistance than stainless steel 316L and ascast HEA,*** enhanced erosion resistances of the processed HEAs correlate to their increased hardness,resistance to plasticity,and better yield strength than the as-cast *** surface of the tested samples showed nucleation and pit growth,and plastic deformation of the material followed by fatigue-controlled disintegration as the primary material removal mechanism.

关键词： cavitation erosion microstructure mechanical properties surface engineering