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Design of crown pillar thickness using finite element method and multivariate regression analysis

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International Journal of Mining Science and Technology 2017年第6期27卷 955-964页

作者： kumar hemant Deb Debasis Chakravarty D. Department of Mining Engineering Indian Institute of Technology (Indian School of Mines) Dhanbad 826004 India Department of Mining Engineering Indian Institute of Technology Kharagpur 721302 India

Minerals are now being extracted from deep mines due to drying up of resource in shallow ground. The need for suitable supports and ground control mechanisms for safe mining necessitates proper pillar design with filling technology. In addition, high horizontal stress may cause collapse of hanging wall and footwall rocks, hence designing of suitable crown pillars is absolutely necessary for imposing overall safety of the stopes. This paper provides a methodology for the evaluation of the required thickness of crown pillars for safe operation at depth ranging from 600 m to 1000 m. Analyses are conducted with the results of 108 non-linear numerical models considering Drucker-Prager material model in plane strain condition. Material properties of ore body rock and thickness of crown pillars are varied and safety factors of pillars estimated. Then, a generalized statistical relationship between the safety factors of crown pillars with the various input parameters is developed. The developed multivariate regression model is utilized for generating design/stability charts of pillars for different geo-mining *** design charts can be used for the design of crown pillar thickness with the depth of the working,taking into account the changes of the rock mass conditions in underground metal mine.

关键词： Cut and fill mining Crown pillar FEM Regression model Design chart

Understanding pore characteristics through core-based petrographic and petrophysical analysis in a heterogeneous carbonate reservoir:A case study from the Mumbai Offshore Basin,India

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Petroleum Research 2023年第4期8卷 469-480页

作者： Ilius Mondal kumar hemant Singh Department of Earth Science Indian Institute of TechnologyBombayIndia

Carbonate rocks exhibit complex and heterogeneous pore structures;such heterogeneity is manifested by the occurrence of a wide variety of pore types with different sizes and geometries as a result of depositional and diagenetic *** complications substantially increase the uncertainty of predicted rock hydraulic parameters because samples with comparable porosities might have very different permeability *** this study,small-scale characterisation of porosity and permeability in heterogeneous Eocene limestone samples from the Bassein Formation of the B-X structure of the MK Field in Mumbai Offshore Basin,India,was carried out,employing an integrated framework that in-corporates thin-section petrography,routine core analysis,mercury injection capillary pressure and nuclear magnetic resonance *** pore characteristics of these carbonates range from poor to *** studied samples exhibited large ranges of porosity,permeability and other associated petrophysical *** pore types,as well as their orientations and connectivity,are the primary factors causing the *** of the complexity of the pore networks,a simple lithofacies classification alone would have been insufficient to link porosity and *** reservoir char-acteristics in the study area are strongly linked to the development and/or destruction of reservoir porosity-permeability during different phases of ***-four carbonate core samples from the limestone unit were studied and classified into microfacies and pore type classes,producing an accurate assessment of reservoir *** comprehensive workflow incorporates the pore volume distributions and pore throat attributes for each rock *** carbonate microfacies were identified by petrographic analysis and their petrophysical characteristics,such as porosity,permeability,pore throat size,pore volume and fluid flow factors,were *** study demonstrates how macro-porosity

关键词： Carbonatereservoir Permeability Mercury injection capillary pressure Nuclear magnetic resonance Porosity partitioning

Fluid substitution in NMR T_(2)distribution and resistivity independent saturation computation using synthetic capillary pressure data

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Petroleum Research 2023年第1期8卷 77-86页

作者： Ilius Mondal kumar hemant Singh Department of Earth Science Indian Institute of Technology BombayIndia

Petrophysicists and reservoir engineers utilise the capillary pressure and saturation-height function for calculating the water saturation of any reservoir,at a given height above the free water *** results have a big impact on reserve *** majority of capillary pressure studies are carried out in labs with core ***,on the other hand,are usually altered from their original state before being delivered to ***,the accuracy of discrete sets of core data in describing entire reservoir parameters,is still up for *** of the capillary pressure curve in reservoir condition is an important subject that is challenging to *** use of nuclear magnetic resonance(NMR)logs for oil and gas exploration has grown in popularity over the last few ***,most of the time the utilization of the data is limited for evaluating porosity-permeability,distributions and computation of irreducible water *** the advent of fluid substitution methods,NMR T_(2)distributions may now be used to synthesize core equivalent capillary pressure *** fluid substitution workflow,our study introduces a better approach for obtaining capillary pressure curves from the NMR T_(2)*** available core data has been used to calculate calibration parameters for better saturation height *** workflow introduces a novel approach in resistivity independent saturation *** the exploratory wells of our study area,computed water saturation derived from the saturation height function exhibits encouraging agreement with resistivity based water saturation from multi-mineral *** NMR based saturation height modelling approach has been included in study area for the first time so far.

关键词： Carbonate reservoir NMR fluid Substitution Capillary pressure Saturation height function Resistivity independent saturation

Core-log integration and application of machine learning technique for better reservoir characterisation of Eocene carbonates,Indian offshore

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Energy Geoscience 2022年第1期3卷 49-62页

作者： Ilius Mondal kumar hemant Singh Indian Institute of Technology Bombay India

Rock types,pore structures and permeability are essential petrophysical outputs,and they contribute considerably to the highest degree of uncertainty in reservoir *** factors have a strong influence on exploration and field development *** analysis is the best approach for estimating permeability,assigning rock types and characterising pore *** logs are the most often employed method for estimating the parameters at each data point of reservoirs since there are more un-cored wells than cored *** intelligence,on the other hand,is gaining popularity in the geosciences due to the ever-increasing complexity and volume of available subsurface *** is also obvious in the demand for faster and more accurate interpretations in order to identify reservoir characteristics in increasingly difficult and complicated petroliferous *** Neural Networks and Self-Organizing Maps are examples of machine learning approaches that can be used in both supervised and unsupervised modes for modelling and *** carbonates of Mukta oilfield are the major pay rocks of strong geological heterogeneity in terms of their porosity and permeability relationship with pore *** paper outlines a novel method of rock fabric classification,pore structure characterization,flow unit classification and robust reservoir permeability modelling based on an integrated approach that incorporates core measurements,log data and machine learning *** pore structure has been characterised by the combination of conventional core,capillary pressure and nuclear magnetic resonance *** neural network has added an adequate benefit in accurate permeability modelling by utilizing the concepts of rock classifications and hydraulic flow units.

关键词： Permeability Microfacies MICP NMR Hydraulic flow unit Artificial neural network Reservoir characterisation

Petrophysical insights into pore structure in complex carbonate reservoirs using NMR data

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Petroleum Research 2024年第3期9卷 439-450页

作者： Ilius Mondal kumar hemant Singh Department of Earth Science Indian Institute of Technology BombayIndia

The study delves into pore structure attributes within the complex Eocene carbonate of an Indian offshore field,encompassing pore throat,radius and their *** Magnetic Resonance(NMR)experimental data reveals crucial insights into pore structures and fluid *** study compares the NMR T_(2) distribution curve with capillary pressure data from the Mercury Injection Capillary Pressure(MICP)technique,deriving linear and nonlinear conversion coefficients to transform NMR T_(2) spectra into equivalent pore radius *** radius-dependent porosity partitioning,linked to permeability and the distribution of irreducible water,is conducted utilizing NMR-derived *** the T_(2) cut-off analysis,a two-segment fractal analysis of NMR T_(2) distribution is also carried *** analysis unveils associations between fractal dimensions and various petrophysical parameters,including permeability,porosity,T_(2)LM,irreducible water saturation and *** NMR-derived pore radius distribution is mostly unimodal,occasionally slightly *** different pore size classes(less than 0.05μm to more than 5μm)are analysed in relation to permeability,porosity and irreducible *** pores(<1μm)contribute more to irreducible water with low porosity and *** fractal dimension of large pores correlates strongly with porosity,permeability,T_(2)LM,irreducible water and Rso suggesting significant impact on reservoir seepage *** addition to porosity partitioning,the current study demonstrates effectiveness in modelling modified permeability and correlating it with in situ permeability when applied to field NMR log data from the study *** numerous studies focus on sandstone,our study marks the pioneering attempt at a comprehensive analysis on complex carbonate reservoirs.

关键词： Pore structure NMR T_(2)distribution Irreducible water Fractal analysis Permeability

Flame spray pyrolysis for the one-step fabrication of transition metal oxide films:Recent progress in electrochemical and photoelectrochemical water splitting

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Chinese Chemical Letters 2020年第3期31卷 601-604页

作者： Hongjun Chen hemant kumar Mulmudi Antonio Tricoli Nanotechnology Research Laboratory Research School of ElectricalEnergy and Materials EngineeringCollege of Engineering and Computer ScienceAustralian National UniversityCanberra 2601Australia

Developing large scale deposition techniques to fabricate thin porous films with suitable opto-electro nic properties for water catalysis is a necessity to mitigate climate change and have a sustainable *** this review,flame spray pyrolysis(FSP)technique,a rapid and scalable methodology to synthesize nanostructured transitional metal oxide films with designed functionalities,is firstly ***,applications in electrochemical(EC)and photoelectrochemical(PEC)water splitting for the production of hydrogen fuel is also *** high combustion temperature and the aggregation of flame aerosol ensure that the FSP-made films possess high crystallinity,tunable porosity and high surface areas,making this method suitable either as catalysts for EC water splitting or as efficient semiconductor materials for PEC water ***,a perspective on the next generation FSP engineered films with potential applications in energy storage and conversion is described.

关键词： Scalable One-step Flame-spray pyrolysis Transition metal oxide Electrochemical Photoelectrochemical Water splitting

Understanding of tip clearance flow structure in high speed mixed flow compressor

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Propulsion and Power Research 2023年第3期12卷 356-379页

作者： hemant kumar Chetan S.Mistry Department of Aerospace Engineering Indian Institute of TechnologyKharagpurWest Bengal 721302India

This paper addresses the necessity to make a physical interpretation of a highly complex three-dimensional tip clearance flow field study for high-speed mixed-flow compressor having stage exit static pressure to inlet total pressure ratio of 3.8 with 39,836 rpm rotor *** four different tip configurations namely the constant(l Z 0.016 and 0.019)and variable(l Z 0.011(inlet)-0.019(exit)and 0.019(inlet)-0.022(exit))tip clearances were numerically analysed using available experimental *** numerical investigation reveals that in contrast to the classic jet-wake pattern,two anomalous velocity profiles formed at the impeller exit which results in pressure losses in the vaneless *** the impeller inlet,the tip leakage flow rolls up to discrete tip leakage vortex structure for each tip clearance *** results in the formation of a region of momentum deficit,recirculation zone,which gets weakened as it moves *** tip clearance configuration is observed to profoundly influence the extent and vorticity of the tip leakage *** the splitter blade passage,the tip leakage flow and Coriolis flow interact with passage flow,resulting in the formation of two secondary passage vortices that move downstream along the pressure and suction surface of the splitter *** tip clearance configuration directly influences the impeller exit jetwake pattern by modulating the secondary passage vortices trajectory and ***,off-design analysis for tip clearances l Z 0.016 and l Z 0.019,depict distinctive tip leakage vortex *** operating near the stall conditions(80%of design mass flow rate),l Z 0.019 exhibits bubble shape tip leakage vortex breakdown occurring near the impeller *** result in a substantial change in the tip leakage vortex nature;expansion of the recirculation zone and early weakening of the vorticity in the tip leakage *** is observed that vortex breakdown plays a vital role in characte

关键词： Recirculation zone Vortex breakdown Tip leakage flow Mixed-flow compressor Jet-wake flow Vaned-diffuser

Energy Efficient Load Balancing and Routing Using Multi-Objective Based Algorithm in WSN

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Intelligent Automation & Soft Computing 2023年第3期35卷 3227-3239页

作者： hemant kumar Vijayvergia Uma Shankar Modani Department of Electronics&Communication Engineering Govt.Mahila Engineering CollegeAjmerRajasthanIndia Department of Electronics&Communication Engineering Govt.Engineering CollegeAjmerIndia

In wireless sensor network(WSN),the gateways which are placed far away from the base station(BS)forward the collected data to the BS through the gateways which are nearer to the *** leads to more energy consumption because the gateways nearer to the BS manages heavy trafﬁc ***,to over-come this issue,loads around the gateways are to be balanced by presenting energy efﬁcient clustering ***,to enhance the lifetime of the net-work,optimal routing path is to be established between the source node and *** energy efﬁcient load balancing and routing,multi objective based beetle swarm optimization(BSO)algorithm is presented in this *** this algo-rithm,optimal clustering and routing are performed depend on the objective func-tions routingﬁtness and clusteringﬁ*** approach leads to decrease the power *** results show that the performance of the pro-posed BSO based clustering and routing scheme attains better results than that of the existing algorithms in terms of energy consumption,delivery ratio,through-put and network ***,the proposed scheme increases throughput to 72%and network lifetime to 37%as well as it reduces delay to 37%than the existing optimization algorithms based clustering and routing schemes.

关键词： Wireless sensor network(WSN) load balancing clustering routing beetle swarm optimization(BSO)

Condition Evaluation in Steel Truss Bridge with Fused Hilbert Transform,Spectral Kurtosis,and Bandpass Filter

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Structural Durability & Health Monitoring 2021年第2期15卷 139-165页

作者： Anshul Sharma Pardeep kumar hemant kumar Vinayak uresh kumar Walia National Institute of Technology Hamirpur177005India Entrepreneurship Development and Industrial Coordination Department National Institute of Technical Teachers Training and ResearchChandigarh160019India Himachal Pradesh Public Works Department Kangra176001India

This study is concerned with the diagnosis of discrepancies in a steel truss bridge by identifying dynamic properties from the vibration response signals of the *** vibration response signals collected at bridges under three different vehicular speeds of 10 km/hr,20 km/hr,and 30 km/hr are analyzed using statistical features such as kurtosis,magnitude of peak-to-peak,root mean square,crest factor as well as impulse factor in time domain,and Stockwell transform in the time-frequency *** considered statistical features except for kurtosis show uncertain *** Stockwell transform showed low-resolution outcomes when the presence of noise in the recorded vibration *** elimination of noise and extraction of meaningful dynamic properties from the vibration responses is done by applying a new method which comes from the fusion of Hilbert transform with Spectral kurtosis and bandpass *** outcomes obtained from Hilbert transform processed residual signals which are further filtered using bandpass filter show more robustness and accuracy in characterizing bridge modal frequencies from the noisy vibration *** proposed method produces a high-resolution frequency response which can unveil the joint discrepancy in the bridge structure.

关键词： Steel bridge damage detection stockwell transform hilbert transform spectral kurtosis bandpass filter