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International Journal of Mining Science and Technology 2017年第2期27卷 261-267页

作者： Das Arka Jyoti Mandal Prabhat Kumar Ghosh Chandra Nath sinha amalendu CSIR-Central Institute of Mining and Fuel Research Dhanbad 826001India

In some of the coalfields in India, coal seams are only developed but no extraction of pillars is possible due to the presence of surface or sub-surface structures and also non-availability of stowing materials which leads to huge amounts of coal being locked-up underground. Spontaneous heating and fire, accumulation of poisonous gases, severe stability issues leading to unsafe workings and environmental hazards are the major problems associated with the developed coal pillars. So, there is a pressing need for a technology for the mining industry to extract the huge amount of coal locked-up under different constraints. In this study, the locked-up coal is proposed to be extracted by artificially strengthening the rib pillars. The detailed comparative study is carried out to know the increase of extraction percentage of locked-up coal by strengthening the rib pillars with FRP. Extraction methodology is designed and studied through numerical modelling for its stability analysis to evaluate its suitability of application in underground.

关键词： Locked-up coal Confined core Yield criterion Strengthened rib pillar Strain softening

Hydrogeochemistry and Quality Assessment of Mine Water of West Bokaro Coalfields, Hazaribag, Jharkhand, India

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材料科学与工程（中英文A版） 2013年第8期3卷 540-549页

作者： Gautam Chandra Mondal Abhay Kumar Singh Tej Bahadur Singh Brajendra Kumar Tewary amalendu sinha CSIR-Central Institute of Mining and Fuel Research Dhanbad 820015 Jharkhand India

Biphasic reduction model for predicting the impacts of dye-bath constituents on the reduction of tris-azo dye Direct Green-1 by zero valent iron(Fe^0)

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Journal of Environmental Sciences 2017年第2期29卷 160-169页

作者： Raja Kumar Alok sinha Department of Environmental Science&Engineering Indian School of MinesDhanbad 826004JharkhandIndia

Influence of common dye-bath additives, namely sodium chloride, ammonium sulphate,urea, acetic acid and citric acid, on the reductive decolouration of Direct Green 1 dye in the presence of Fe0 was investigated. Organic acids improved dye reduction by augmenting Fe0 corrosion, with acetic acid performing better than citric acid. Na Cl enhanced the reduction rate by its ‘salting out’ effect on the bulk solution and by Cl-anion-mediated pitting corrosion of iron surface.（NH4）2SO4induced ‘salting out’ effect accompanied by enhanced iron corrosion by SO42-anion and buffering effect of NH4＋ improved the reduction ***, at 2 g/L（NH4）2SO4concentration, complexating of SO42-with iron oxides decreased Fe0 reactivity. Urea severely compromised the reduction reaction, onus to its chaotropic and‘salting in’ effect in solution, and due to it masking the Fe0 surface. Decolouration obeyed biphasic reduction kinetics（R2〉 0.993 in all the cases） exhibiting an initial rapid phase,when more than 95% dye reduction was observed, preceding a tedious phase. Maximum rapid phase reduction rate of 0.955/min was observed at p H 2 in the co-presence of all dye-bath constituents. The developed biphasic model reckoned the influence of each dye-bath additive on decolouration and simulated well with the experimental data obtained at pH 2.

关键词： Biphasic kinetics/model Direct Green 1 Dye-bath additives Fe0

Telemedicine and public health–pearls and pitfalls

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World Journal of Methodology 2025年第2期15卷 177-179页

作者： Ranjeet Kumar sinha Sony sinha Prateek Nishant Arvind Kumar Morya Arshi Singh Department of Community Medicine Patna Medical CollegePatna 800004BiharIndia Department of Ophthalmology-Vitreo-Retina Neuro-Ophthalmology and OculoplastyAll India Institute of Medical SciencesPatna 801507BiharIndia Department of Ophthalmology ESIC Medical CollegePatna 801103BiharIndia Department of Ophthalmology All India Institute of Medical SciencesHyderabad 508126TelanganaIndia Department of Ophthalmology Guru Nanak Eye CenterNew Delhi 110001India

We hereby comment on the interesting systematic review by Grewal et al where they have provided an overall picture of the current status of available tele-health programs in the United States with emphasis on the Amazon *** analysis is an appreciable effort in discovering the features available and features lacking in these tele-health *** concept of tele-health originated to curtail the need for physical attendance of patients at health clinics,and has been beneficial during the coronavirus disease 2019 *** implore that the pearls and pitfalls of these programs have to be understood by policymakers prior to forming a consensus regarding the availability,accessibility and affordability of these programs as methods of healthcare *** proliferation of tele-health programs in their current form may pose threats to patient and provider safety and medicolegal ***,patients and providers must work together to improve them to meet their expectations and enable them to provide the best care for the ailing public.

关键词： Telemedicine Remote Access Availability Accessibility Affordability Ethics Privacy Medicolegal liability

Generation scenarios of anodic structures and experimental realization of turbulence in unmagnetized plasma

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Plasma Science and Technology 2020年第8期22卷 90-98页

作者： Prince ALEX Suraj Kumar sinha Departimento di Fisica G.Occhialini Universita degli studi di MilanoBicoccaI-20126Italy Department of Physics Pondicherry UniversityKalapetPuducherry 605014India

In the present work,we report development of a DC glow discharge plasma(GDP)set-up to study controlled evolution of anodic structures having distinctive geometry,size and layers,generated in front of a positively biased electrode,submerged in unmagnetized *** such an anodic structure,we have also investigated the condition under which the turbulence is *** of these structures,generated in front of a positively biased electrode,depends on multiple parameters such as the ratio of anode to cathode size,electrode separation,gas pressure,biasing configuration such as anode bias,cathode bias and grounding *** attempted to classify different anodic structures observed experimentally,as anode glow,fireball,anode spot,double layer and multiple double layers(MDLs)based on its physical *** these structures the present investigation is focused on *** number of layers,observed in MDLs varied from as high as six to as low as zero,by controlling the operating discharge parameters,*** were carried out using Langmuir *** analysis of floating potential fluctuations corresponds to a multiple anodic structure showed emergence of turbulence,at its critical stage,satisfying condition for self-organized criticality(SOC).This was identified with three slopes observed in the power spectrum,resembling the sand-pile ***,the GDP is completely different from that of the magnetically confined plasma,the nature of turbulence observed with SOC,is very similar to that observed in the scrape of layer of fusion ***,the present investigation could provide new approach to study turbulence of similar nature,under an experimental condition that is free from the complexities of complicated field geometries used in confinement devices.

关键词： glow discharge plasma anode structure multiple anodic double layer turbulence unmagnetized plasma fireball

Challenges associated with numerical back analysis in rock mechanics

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第6期14卷 2058-2071页

作者： Gabriel Walton Sankhaneel sinha Department of Geology and Geological Engineering Colorado School of MinesGoldenCO80401USA

Numerical back analysis is a valuable tool available to rock mechanics researchers and *** studies related to back analysis methods focused primarily on applications of increasingly sophisticated optimization algorithms(primarily machine learning algorithms)to rock mechanics *** methods have typically been applied to relatively simple problems;however,more complex back analyses continue to be conducted primarily through ad hoc manual trial-and-error *** paper provides a review of the basic concepts and recent developments in the field of numerical back analysis for rock mechanics,as well as some discussion of the relationship between back analysis and more broadly established frameworks for numerical *** challenges of flexible constraints,non-uniqueness,material model limitations,and disparate data sources are considered,and representative case studies are presented to illustrate their impacts on back *** role of back analysis(or“model calibration”)in bonded particle modelling(BPM),bonded block modelling(BBM),and synthetic rock mass(SRM)modelling is also considered,and suggestions are made for further studies on this topic.

关键词： Back analysis Numerical modelling Inversion Case studies

Modeling behaviors of a coal pillar rib using the progressive S-shaped yield criterion

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 484-492页

作者： Sankhaneel sinha Gabriel Walton Colorado School of Mines GoldenCO80401USA

Spalling of pillar ribs has been a major hazard in the mining industry for *** the absence of rib support guidelines,accidents have continued to occur in recent *** effective support guidelines requires a complete understanding of complex pillar damage *** models represent a convenient tool for analyzing this problem,but the behavior of such models is dependent of the choice of the constitutive *** this study,a recently proposed constitutive model was used to simulate the rib fracturing process in a longwall chain pillar at West Cliff *** calibration,the model was able to capture the rib displacement profiles for multiple locations of the longwall face and the stress evolution 4 m into the *** rib bolts in the model were found to be yielding over 60% of their length under the headgate loading *** model also predicted a steady damage accumulation in the rib for certain face locations,which is consistent with the description of the rib at the *** was localized along the upper part of the pillar and underscored the role that the dirt band played in controlling rib deterioration at the *** ability of the numerical model to replicate field measurements provides confidence in the capabilities of the new constitutive ***,the need of using multi-point calibration is highlighted by comparing the results of the calibrated model to an alternative model calibrated to a smaller amount of data.

关键词： S-shaped yield criterion Coal pillar Back-analysis Numerical modeling

Integration of three-dimensional continuum model and two-dimensional bonded block model for studying the damage process in a granite pillar at the Creighton Mine,Sudbury,Canada

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 275-288页

作者： Sankhaneel sinha Gabriel Walton Geology and Geological Engineering Colorado School of MinesGoldenCO80401USA

Bonded blockmodel(BBM)has shownpotential in replicating rockmass behavior aswell as the rockesupport interactionmechanism,but their practical application is limited totwo dimensions due to the high associated computational *** allow for the use of BBM in simulating three-dimensional(3D)problems,this study proposes an integrated 3D continuumetwo-dimensional(2D)discontinuum approach,in context of rock pillars.A cross-section of a granite pillar was simulated using a BBM with a load path from a calibrated mine-scale FLAC^(3D)*** support as employed in the mine was also incorporated in different stages during the *** was calibrated by varying the input parameters until the displacements at six locations within the pillarmatchedthosemeasuredby amulti-point borehole extensometer(MPBX)inthe *** calibratedmodel was subsequently used to understand how the support and load path influenced the damage evolution in the *** shear component of the load pathwas found to have amajor effect on the severity and extent of the damaged *** the support density was increased in the model,the lateral displacements along the pillar walls were significantly suppressed in a somewhat unpredictable *** explained by the interaction between the supports and the damaged regions at the corners,which ultimately modified the stresses along the pillar *** amount of displacement reduction obtained by increasing the support density illustrates the potential of BBMto be used as a support design tool.

关键词： Bonded block model(BBM) Rock pillars Supports Continuum-discontinuum integration

Understanding roof deformation mechanics and parametric sensitivities of coal mine entries using the discrete element method

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International Journal of Mining Science and Technology 2020年第1期30卷 123-129页

作者： Rami Abousleiman Gabriel Walton Sankhaneel sinha Department of Geology and Geological Engineering Colorado School of MinesGoldenCO 80218USA

Although conventional coal mine designs are conservative regarding pillar strength,local failures such as roof-falls and pillar bursts still affect mine safety and *** studies have identified that discontinuous,layered roof materials have some self-supporting *** research is a preliminary step towards understanding these mechanics in coal-measure *** others have considered broad conceptual models and simplified analogs for mine roof behavior,this study presents a unique numerical model that more completely represents in-situ roof *** discrete element method(DEM)is utilized to conduct a parametric analysis considering a range of in-situ stress ratios,material properties,and joint networks to determine the parameters controlling the stability of single-entries modeled in *** results are compared to empirical observations of roof-support effectiveness(ARBS)in the context of the coal mine roof rating(CMRR)*** such as immediate roof displacement,overall stability,and statistical relationships between model parameters and outcomes are presented *** practical applications of this line of research include:(1)roof-support optimization for a range of coal-measure rocks,(2)establishment of a relationship between roof stability and pillar stress,and(3)determination of which parameters are most critical to roof stability and therefore require concentrated evaluation.

关键词： Numerical modeling Discrete element method Coal mine roof rating Analysis of roof bolt systems Sensitivity analysis Strain softening ubiquitous joints Discrete fracture network

Temperature-dependent structural,morphological and optical properties of chemical bath-deposited CdS films

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Rare Metals 2021年第3期40卷 701-707页

作者： Tarkeshwar sinha Devjyoti Lilhare Ayush Khare Department of Physics National Institute of TechnologyRaipur 492010India

Cadmium sulfide(CdS) films were grown on top of the fluorine-doped tin oxide(FTO) coated glass substrates at four different bath temperatures by chemical bath deposition(CBD) technique.X-ray diffraction(XRD),ultraviolet-visible(UV-Vis) spectrometry,energy-dispersive X-ray spectroscopy(EDX),field emission scanning electron microscope(FESEM),photoluminescence(PL)and Fourier-transform infrared(FTIR) analyses were employed to examine the morphological and optical properties of deposited *** studies confirmed the cubic crystalline nature of the deposited films which improved with increase in deposition temperature,and EDX along with FESEM study showed that the films were smooth and uniform with appropriate chemical ***-gap values of the CBD CdS films calculated by UV-Vis spectrometry were found to be in the range of2.32-2.39 eV.A strong blue band and a weak green band were observed in PL emission spectra.C-S,Cd-S and SC-N vibrations were found by FTIR spectral analysis.

关键词： CdS Thin films CBD Bath temperature Photoluminescence