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Evaluation of mine scale longwall top coal caving parameters using continuum analysis

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Mining Science and Technology 2011年第6期21卷 787-796页

作者： Manoj Khanal deepak adhikary Rao Balusu Earth Science and Resource Engineering Commonwealth Scientific and Industrial Research OrganizationQueensl and Center for Advanced Technology1Technology CourtPullenvaleQLD4069Australia

A mine-scale analysis of Longwall Top Coal Caving (LTCC) is performed using a continuum mechanics finite element solver called COSFLOW. The uniqueness of COSFLOW is that it incorporates Cosserat continuum theory in its formulation for describing the load deformation of bedded rocks. It is shown that such a continuum based code is valuable for assessing the feasibility of introducing LTCC in any mine. Various LTCC parameters, for example chock convergences, top coal failure behavior, strata cavingmechanism, abutment stresses and vertical stresses, were evaluated for a mine using COSFLOW.

关键词： LTCC COSFLOW Cosserat FEM Modeling Simulation

Numerical Modeling of Porous Flow in Fractured Rock and Its Applications in Geothermal Energy Extraction

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Journal of Earth Science 2015年第1期26卷 20-27页

作者： Yucang Wang Shimin Wang Sheng Xue deepak adhikary Earth Science and Resource Engineering CSIROKenmore Qld 4069BrisbaneAustralia Key Laboratory of Computational Geodynamics University of Chinese Academy of Sciences

Understanding the characteristics of hydraulic fracture, porous flow and heat transfer in fractured rock is critical for geothermal power generation applications, and numerical simulation can provide a powerful approach for systematically and thoroughly investigating these problems. In this paper, we present a fully coupled solid-fluid code using discrete element method （DEM） and lattice Boltzmann method （LBM）. The DEM with bonded particles is used to model the deformation and fracture in solid, while the LBM is used to model the fluid flow. The two methods are two-way coupled, i.e., the solid part provides a moving boundary condition and transfers momentum to fluid, while the fluid exerts a dragging force to the solid. Two widely used open source codes, the ESyS Particle and the OpenLB, are integrated into one code and paralleled with Message Passing Interface （MPI） library. Some preliminary 2D simulations, including particles moving in a fluid and hydraulic fracturing induced by injection of fluid into a borehole, are carried out to validate the integrated code. The preliminary results indicate that the new code is capable of reproducing the basic features of hydraulic fracture and thus offers a promising tool for multiscale simulation of porous flow and heat transfer in fractured rock.

关键词： discrete element method lattice Boltzmann method hydraulic fracturing geothermalenergy extraction multiscale modelling.

Effect of strata properties and panel widths on chock performance

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Journal of Rock Mechanics and Geotechnical Engineering 2011年第S1期3卷 407-414页

作者： Manoj Khanal deepak adhikary Rao Balusu Earth Science and Resource Engineering Commonwealth Scientific and Industrial Research Organization (CSIRO) ClaytonVIC 3169Australia Queensland Center for Advanced Technology Commonwealth Scientific and Industrial Research Organization(CSIRO)Pullenvale QLD 4069Australia

The selection of optimum chock (support) capacity is very crucial for a successful longwall mining. The selection of chock capacity depends on the site-specific geotechnical parameters, constraints and longwall panel geometry, which are generally not known in detail in priority. Hence, based on the field and laboratory data, various possible combinations should be analyzed to cater for the unforeseeable mining conditions. This paper discusses the use of numerical model for selecting an appropriate chock capacity based on the site-specific geological and geotechnical information and longwall panel geometry. The fracture mechanisms of immediate and main roofs are also discussed for various panel widths and support capacities. For the models considered, the chock convergence is predicted to increase by about 33% due to the increase in face width from 100 to 260 m. Similarly, the massive roof strata are found to yield higher chock convergence compared to bedded strata.

关键词： chock capacity longwall simulation underground mining

Comprehensive G?bner Basis Theory for a Parametric Polynomial Ideal and the Associated Completion Algorithm

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Journal of Systems Science & Complexity 2017年第1期30卷 196-233页

作者： KAPUR deepak Department of Computer Science University of New Mexico Albuquerque NM USA.

Groebner basis theory for parametric polynomial ideals is explored with the main objec- tive of nfinicking the Groebner basis theory for ideals. Given a parametric polynomial ideal, its basis is a comprehensive GrSbner basis if and only if for every specialization of its parameters in a given field, the specialization of the basis is a GrSbnerbasis of the associated specialized polynomial ideal. For various specializations of parameters, structure of specialized ideals becomes qualitatively different even though there are significant relationships as well because of finiteness properties. Key concepts foundational to GrSbner basis theory are reexamined and/or further developed for the parametric case：（i） Definition of a comprehensive Groebner basis, （ii） test for a comprehensive GrSbner basis, （iii） parameterized rewriting, （iv） S-polynomials among parametric polynomials, （v） completion algorithm for directly computing a comprehensive Groebner basis from a given basis of a parametric ideal. Elegant properties of Groebner bases in the classical ideal theory, such as for a fixed admissible term ordering, a unique GrSbner basis can be associated with every polynomial ideal as well as that such a basis can be computed from any Groebner basis of an ideal, turn out to be a major challenge to generalize for parametric ideals; issues related to these investigations are explored. A prototype implementation of the algorithm has been successfully tried on many examples from the literature.

关键词： Comprehensive GrSbner basis minimal comprehensive GrSbner basis parametric polyno-mial system parametric S-polynomial redundancy.

Conditional Congruence Closure over Uninterpreted and Interpreted Symbols

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Journal of Systems Science & Complexity 2019年第1期32卷 317-355页

作者： KAPUR deepak Department of Computer Science University of New Mexico

A framework for generating congruence closure and conditional congruence closure of ground terms over uninterpreted as well as interpreted symbols satisfying various properties is proposed. It is based on some of the key concepts from Kapur's congruence closure algorithm(RTA97)for ground equations based on introducing new symbols for all nonconstant subterms appearing in the equation set and using ground completion on uninterpreted constants and puri?ed equalities over interpreted symbols belonging to different theories. In the original signature, the resulting rewrite systems may be nonterminating but they still generate canonical forms. A byproduct of this framework is a constant Horn completion algorithm using which ground canonical Horn rewrite systems can be generated for conditional ground *** effcient algorithms for generating congruence closure of conditional and unconditional equations on ground terms over uninterpreted symbols are presented. The complexity of the conditional congruence closure is shown to be O(n*log(n)), which is the same as for unconditional ground *** proposed algorithm is motivated by our attempts to generate effcient and succinct interpolants for the quanti?er-free theory of equality over uninterpreted function symbols which are often a conjunction of conditional equations and need additional simpli?cation. A completion algorithm to generate a canonical conditional rewrite system from ground conditional equations is also presented. The framework is general and ?exible and is used later to develop congruence closure algorithms for cases when function symbols satisfy simple properties such as commutativity, nilpotency, idempotency and identity as well as their combinations. Interesting outcomes include algorithms for canonical rewrite systems for ground equational and conditional theories on uninterpreted and interpreted symbols leading to generation of canonical forms for ground terms, constrained terms and Horn equat

关键词： Completion congruence closure conditional congruence closure intepreted symbols rewrit-ing uninterpreted symbols

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

Effectiveness of state incentives for promoting wind energy： A panel data examination

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Frontiers in Energy 2015年第3期9卷 247-258页

作者： deepak SANGROYA Jogendra NAYAK Department of Management Studies Indian Institute of Technology IIT Roorkee Roorkee 247667 India

Over the last decade, India has started to concentrate earnestly on renewable energy. The Indian government, as well as different state governments, are adopting policy instruments such as feed in tariff, captive consumption, renewable purchase obligation and genera- tion based incentive etc. aimed at renewable energy development. This paper evaluates the effectiveness of state level incentives for the development of wind energy in India. Fixed effect panel data modelling technique of econometric analysis is used to analyse the data of 26 Indian states in 11 years. The results show that feed in tariff and captive consumption are the significant predictors of wind energy development. However, renewable purchase obligation does not affect wind energy significantly.

关键词： India wind energy development state incen-tives econometric analysis panel data

Design optimization of first wall and breeder unit module size for the Indian HCCB blanket module

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Plasma Science and Technology 2018年第6期20卷 200-210页

作者： deepak SHARMA Paritosh CHAUDHURI Institute for Plasma Research Bhat Gandhinagar Gujarat-382428 India

The Indian test blanket module（TBM） program in ITER is one of the major steps in the Indian fusion reactor program for carrying out the R＆D activities in the critical areas like design of tritium breeding blankets relevant to future Indian fusion devices（ITER relevant and DEMO）.The Indian Lead–Lithium Cooled Ceramic Breeder（LLCB） blanket concept is one of the Indian DEMO relevant TBM,to be tested in ITER as a part of the TBM ***-Cooled Ceramic Breeder（HCCB） is an alternative blanket concept that consists of lithium titanate（Li_2TiO_3） as ceramic breeder（CB） material in the form of packed pebble beds and beryllium as the neutron ***,attentions are given to the optimization of first wall coolant channel design and size of breeder unit module considering coolant pressure and thermal loads for the proposed Indian HCCB blanket based on ITER relevant TBM and loading *** analyses will help proceeding further in designing blankets for loads relevant to the future fusion device.

关键词： first wall blanket breeder unit thermal hydraulics structural analysis HCCB(helium-cooled ceramic breeder)

ON INVARIANT CHECKING

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Journal of Systems Science & Complexity 2013年第3期26卷 470-482页

作者： ZHANG Zhihai KAPUR deepak School of Mathematical Sciences Peking University Department of Computer Science University of New Mexico

Checking whether a given formula is an invariant at a given program location(especially,inside a loop) can be quite nontrivial even for simple loop programs,given that it is in general an undecidable *** is especially the case if the given formula is not an inductive loop invariant,as most automated techniques can only check or generate inductive loop *** this paper,conditions are identified on simple loops and formulas when this check can be performed automatically.A general theorem is proved which gives a necessary and sufficient condition for a formula to be an invariant under certain restrictions on a *** a byproduct of this analysis,a new kind of loop invariant inside the loop body,called inside-loop invariant,is *** an invariant is more general than an inductive loop invariant typically used in the Floyd-Hoare axiomatic approach to program *** use of such invariants for program debugging is explored;it is shown that such invariants can be more useful than traditional inductive loop invariants especially when one is interested in checking extreme/side conditions such as underflow,accessing array/collection data structures outside the range,divide by zero,etc.

关键词： Assertion Floyd-Hoare logic invariant invariant generation.