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Correlations between mineral composition and mechanical properties of granite using digital image processing and discrete element method

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International Journal of mining Science and technology 2023年第8期33卷 949-962页

作者： Changdi He Brijes Mishra Qingwen Shi Yun Zhao Dajun Lin Xiao Wang department of mining engineering University of UtahSalt Lake City 84112USA College of Mine Safety North China Institute of Science and TechnologyLangfang 065201China department of mining engineering West Virginia UniversityMorgantown 26506USA department of electrical and Computer engineering University of UtahSalt Lake City 84112USA College of Energy and mining engineering Shandong University of Science and TechnologyQingdao 266590China

This study investigated the correlations between mechanical properties and mineralogy of granite using the digital image processing(DIP) and discrete element method(DEM). The results showed that the X-ray diffraction(XRD)-based DIP method effectively analyzed the mineral composition contents and spatial distributions of granite. During the particle flow code(PFC2D) model calibration phase, the numerical simulation exhibited that the uniaxial compressive strength(UCS) value, elastic modulus(E), and failure pattern of the granite specimen in the UCS test were comparable to the experiment. By establishing 351 sets of numerical models and exploring the impacts of mineral composition on the mechanical properties of granite, it indicated that there was no negative correlation between quartz and feldspar for UCS, tensile strength(σ_(t)), and E. In contrast, mica had a significant negative correlation for UCS, σ_(t), and E. The presence of quartz increased the brittleness of granite, whereas the presence of mica and feldspar increased its ductility in UCS and direct tensile strength(DTS) tests. Varying contents of major mineral compositions in granite showed minor influence on the number of cracks in both UCS and DTS tests.

关键词： Granite Digital image processing Discrete element method Mineral composition Mechanical properties

Bioleaching of copper oxide ore by P seudomonas aeruginosa

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International Journal of Minerals,Metallurgy and Materials 2013年第12期20卷 1130-1133页

作者： M.A.Shabani M.Irannajad A.R.Azadmehr M.Meshkini department of mining & Metallurgical engineering Amirkabir University of Technology Iranian Academic center for Education Culture and Research (ACECR)Branch of Amirkabir

Bioleaching is an environmentally friendly method for extraction of metal from ores. In this study, bioleaching of copper oxide ore by Pseudomonas aeruginosa was investigated. Pseudomonas aeruginosa is a heterotrophic bactermm that can produce various organic acids in an appropriate culture medium, and these acids can operate as leaching agents. The parameters, such as particle size, glucose percentage in the culture medium, bioleaching time, and solid/liquid ratio were optimized. Optimum bioleaching conditions were found as follows： particle size of 150-177 μm, glucose percentage of 6%, bioleaching time of 8 d, and solid/liquid ratio of 1：80. Under these conditions, 53% of copper was extracted.

关键词： copper ore treatment copper oxides bioleaching organic acids heterotrophic bacteria Pseudomonas aeruginosa

The Influence of Normal Load and Sliding Speed on Frictional Properties of Skin

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Journal of Bionic engineering 2008年第1期5卷 33-38页

作者： Wei Tang Shi-rong Ge Hua Zhu Xi-chuan Cao Ning Li Institute of Tribology and Reliability engineering School of Mechanical and Electrical Engineering China University of Mining and Technology Xuzhou 221116 P. R. China Biotribology center of the State Key Laboratory of Tribology China University of Mining and Technology Xuzhou 221116 P. R. China

The study of frictional properties of human skin is important for medical research, skin care products and textile exploi- tation. In order to investigate the influence of normal load and sliding speed on the frictional properties of skin and its possible mechanism, tests were carded out on a multi-specimen friction tester. When the normal load increases from 0.1 N to 0.9 N, normal displacement and the friction coefficient of skin increase. The friction coefficient is dependent on the load, indicating that both adhesion and deformation contribute to the friction behaviour. The deformation friction was interpreted using the plough model of friction. When sliding speed increases from 0.5 mm·s^-1 to 4 mm·s^-1, the friction coefficient increases and ＂stick-slip＂ phenomena increase, indicating that hysteretic friction contributes to the friction. The hysteretic friction was in- terpreted using schematic of energy translation during the rigid spherical probe sliding on the soft skin surface, which provides an explanation for the influence of the sliding speed on the frictional characteristics of the skin.

关键词： normal load sliding speed friction coefficient skin

Kinematic Analysis of an Under-actuated,Closed-loop Front-end Assembly of a Dragline Manipulator

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International Journal of Automation and computing 2020年第4期17卷 527-538页

作者： Muhammad AWardeh Samuel Frimpong department of mining and Nuclear engineering Missouri University of Science and TechnologyRolla 65409USA center for Infrastructure engineering Studies Missouri University of Science and TechnologyRolla 65409USADepartment of Mining and Nuclear EngineeringMissouri University of Science and TechnologyRolla 65409USA

Dragline excavators are closed-loop mining manipulators that operate using a rigid multilink framework and rope and rigging system,which constitute its front-end *** arrangements of dragline front-end assembly provide the necessary motion of the dragline bucket within its operating *** assembly resembles a five-link closed kinematic chain that has two independent generalized coordinates of drag and hoist ropes and one dependent generalized coordinate of dump *** models failed to represent the actual closed loop of dragline front-end assembly,nor did they describe the maneuverability of dragline ropes under imposed geometric ***,a three degrees of freedom kinematic model of the dragline front-end is developed using the concept of generalized *** contains all relevant configuration and kinematic constraint conditions to perform complete digging and swinging *** model also uses three inputs of hoist and drag ropes linear and a rotational displacement of swinging along their *** inverse kinematics is resolved using a feedforward displacement algorithm coupled with the Newton-Raphson method to accurately estimate the trajectories of the *** trajectories are solved only during the digging phase and the singularity was eliminated using Baumgarte's stabilization technique(BST),with appropriate inequality constraint *** is shown that the feedforward displacement algorithm can produce accurate trajectories without the need to manually solve the inverse kinematics from the *** research findings are well in agreement with the dragline real operational limits and they contribute to the efficiency and the reduction in machine downtime due to better control strategies of the dragline cycles.

关键词： Dragline mining manipulator underactuated closed-loop mechanism generalized speeds Baumgarte's stabilization technique(BST) feedforward displacement

Chaos suppression of uncertain gyros in a given finite time

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Chinese Physics B 2012年第11期21卷 126-131页

作者： Mohammad Pourmahmood Aghababa Hasan Pourmahmood Aghababa electrical engineering department Urmia University of Technology department of Mathematics University of Tabriz Research center for Industrial Mathematics of University of Tabriz

The gyro is one of the most interesting and everlasting nonlinear dynamical systems, which displays very rich and complex dynamics, such as sub-harmonic and chaotic behaviors. We study the chaos suppression of the chaotic gyros in a given finite time. Considering the effects of model uncertainties, external disturbances, and fully unknown parameters, we design a robust adaptive finite-time controller to suppress the chaotic vibration of the uncertain gyro as quickly as possible. Using the finite-time control technique, we give the exact value of the chaos suppression time. A mathematical theorem is presented to prove the finite-time stability of the proposed scheme. The numerical simulation shows the efficiency and usefulness of the proposed finite-time chaos suppression strategy.

关键词： chaos suppression chaotic gyro finite-time stability robustness

Topological horseshoe analysis and field-programmable gate array implementation of a fractional-order four-wing chaotic attractor

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Chinese Physics B 2018年第1期27卷 300-306页

作者：董恩增王震于晓陈增强王增会 Tianjin Key Laboratory For Control Theory & Applications in Complicated Systems Tianjin University of Technology department of Automation Nankai University department of electrical and mining engineering University of South Africa

We present a fractional-order three-dimensional chaotic system, which can generate four-wing chaotic attractor. Dy- namics of the fractional-order system is investigated by numerical simulations. To rigorously verify the chaos properties of this system, the existence of horseshoe in the four-wing attractor is presented. Firstly, a Poincar6 section is selected properly, and a first-return Poincar6 map is established. Then, a one-dimensional tensile horseshoe is discovered, which verifies the chaos existence of the system in mathematical view. Finally, the fractional-order chaotic attractor is imple- mented physically with a field-programmable gate array （FPGA） chip, which is useful in further engineering applications of information encryption and secure communications.

关键词： fractional-order chaotic system Poincar6 map topological horseshoe field-programmable gatearray (FPGA)

An investigation of the persistence property of wind power time series

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Science China(Technological Sciences) 2014年第8期57卷 1578-1587页

作者： SUN HaiShun LI JiaMing LI JingHua Wu Tong WEN JinYu XIE HaiLian YUE ChengYan China State Key Laboratory of advanced Electromagnetic engineering and technology Huazhong University of Science and TechnologySchool of Electrical and Electronic Engineering ABB (China) Ltd. Corporate Research Center

mining the inherent persistence property of the time series of wind power is crucial for forecasting and controlling wind *** common methods exist that can fully depict and quantify the persistence *** on the definition of the active power output state of a wind farm,this paper describes the statistical persistence property of the duration time and state *** on the results of our analysis of significant amounts of wind power field measurements,it is found that the duration time of wind power conforms to an inverse Gaussian ***,the state transition matrix of wind power is discovered to yield a ridge property,the gradient of which is related to the time scale of interest.A systemaic methodology is proposed accordingly,allowing the statistical characteristics of the wind power series to be represented appropriately.

关键词： characteristics analysis persistence property duration time state transition wind power series

Industrial development of gas induced semi-solid process

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中国有色金属学会会刊：英文版 2010年第S3期20卷 1016-1021页

作者： S.THANABUMRUNGKUL S.JANUDOM R.BURAPA P.DULYAPRAPHANT J.WANNASIN department of mining and Materials engineering Faculty of EngineeringPrince of Songkla University department of Industrial engineering Faculty of EngineeringRajamangala University of Technology Srivijaya National Metal and Materials technology center Thailand Science ParkKlong LuangPathumthani 12120Thailand

The gas induced semi-solid(GISS) is a rheocasting process that produces semi-solid slurry by applying fine gas bubble injection through a graphite *** process is developed to be used in the die casting *** apply the GISS process with a die casting process,a GISS maker unit is designed and attached to a conventional die casting machine with little *** commercial parts are developed and produced by the GISS die casting *** GISS die casting shows the feasibility to produce industrial parts with aluminum 7075 and A356 with lower porosity than liquid die casting.

关键词： gas induced semi-solid(GISS) rheocasting die casting semi-solid metal industrial applications

An Improved Differential Evolution Trained Neural Network Scheme for Nonlinear System Identification

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International Journal of Automation and computing 2009年第2期6卷 137-144页

作者： Bidyadhar Subudhi Debashisha Jena center for Industrial Electronics & Robotics Department of Electrical Engineering National Institute of Technology

This paper presents an improved nonlinear system identification scheme using di？erential evolution （DE）, neural network （NN） and Levenberg Marquardt algorithm （LM）. With a view to achieve better convergence of NN weights optimization during the training, the DE and LM are used in a combined framework to train the NN. We present the convergence analysis of the DE and demonstrate the efficacy of the proposed improved system identification algorithm by exploiting the combined DE and LM training of the NN and suitably implementing it together with other system identification methods, namely NN and DE＋NN on a number of examples including a practical case study. The identification results obtained through a series of simulation studies of these methods on different nonlinear systems demonstrate that the proposed DE and LM trained NN approach to nonlinear system identification can yield better identification results in terms of time of convergence and less identification error.

关键词： Differential evolution neural network (NN) nonlinear system identification Levenberg Marquardt algorithm