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Bioleaching of sphalerite sample from Kooshk lead-zinc tailing dam

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Transactions of Nonferrous Metals society of China 2013年第12期23卷 3763-3769页

作者： J.V.MEHRABANI s.z.shafaei M.NOAPARAsT s.M.MOUsAVI M.M.RAJAEI school of Mining Engineering College of Engineering University of Tehran Biotechnology Group Chemical Engineering Department Tarbiat Modares University

The zinc extraction from Kooshk lead-zinc tailing dam’s sample was investigated by bioleaching method. The Kooshk lead-zinc deposit/mine is located in Yazd province, Iran, and its tailing dam contains about 3.64%zinc, 0.97%lead and 24.18%iron. Experiments were designed and carried out by a mixed culture of mesophile bacteria as well as a mixed culture of moderate thermophile strain in the shake flasks. The results indicated that, more than 90% of sphalerite was dissolved during 14 d, while without bacteria, 44% of zn was merely extracted. In addition, some experiments were performed in the absence of the bacterial medium （9K）. The results of these experiments indicated significant difference in zn extraction with and without 9K until the 10th day of bioleaching, but after that the zn extraction was improved and the same extraction was achieved at the end of bioleaching tests. This improvement can be attributed to the increase of the number of bacteria or Fe3＋concentration at the last days of leaching. zn extraction kinetics of moderate thermophile bacteria was significantly higher than that of the mesophile, therefore sphalerite was successfully dissolved in preference to the pyrite using moderate thermophile bacteria in a lower redox potential.

关键词： bioleaching pyrite tailing sphalerite

A mathematical model to simulate Heap(bio)-leaching process:An exact conceptual model,Homotopy theory and comparative insights with conventional methods

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International Journal of Modeling, simulation, and scientific Computing 2017年第1期8卷 271-296页

作者： M.Yaghobi Moghaddam s.z.shafaei Tonkaboni M.Noaparast F.Doulati Ardejani school of Mining College of Engineering University of TehranP.O.Box 14395-515TehranIran

This paper attempts to address some nonlinear differential equations which describe main mechanisms governing heap(bio)leaching process as an important metallurgical facility in mining and mineral processing *** Homotopy Perturbation Method(HPM),Finite Volume Method and Analytical(Laplace)Method have been employed to provide proper solutions for these *** was made between the methods and agreement was close;considering the fact that the proposed solution in comparison with the others provided a remarkable accuracy in dealing with nonlinear problems associated with mining and mineral processing *** maximum error of HPM in relation to the analytical solution was *** numerical finite volume method incorporating a computational fluid dynamics model termed PHOENICs provided rational and accurate results;describing that many chemical and biological processes extremely affect the transportation mechanism of the aqueous compounds in a heap structure and subsequently on the process ***,all solution methods presented to simulate heap leaching process provided valuable information related to the time dependence concentrations of dissolved *** results obtained from this study can be effectively applied to manage the heap leaching costs to make the process feasible.

关键词： Diffusion-advection-reaction equations nonlinear problems Homotopy perturbation method finite volume method analytical solution Heap(bio)-leaching

Empirical model for bio-extraction of copper from low grade ore using response surface methodology

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Transactions of Nonferrous Metals society of China 2015年第12期25卷 4126-4143页

作者： M.YAGHOBI MOGHADDAM s.z.shafaei M.NOAPARAsT F.DOULATI ARDEJANI H.ABDOLLAHI M.RANJBAR M.sCHAFFIE z.MANAFI school of Mining College of Engineering University of Tehran Department of Mining Engineering Shahid Bahonar University of Kerman Department of Chemical Engineering Shahid Bahonar University of Kerman Hydrometallurgy Research Unit R&D Center Sarcheshmeh Copper Mine Complex

The copper extraction in shaking bioreactors was modeled and optimized using response surface methodology（RsM）. Influential parameters in the mesophilic bioleaching process of a low-grade copper ore including p H value, pulp density, and initial concentration of ferrous ions were comprehensively studied. The effect of leaching time on the response（copper extraction） at the 1st, 4th, 9th, 14 th and 22 nd days of treatment was modeled and examined. The central composite design methodology（CCD） was used as the design matrix to predict the optimal level of these parameters. Then, the model equation at the 22 nd day was optimized using the quadratic programming（QP） to maximize the total copper extraction within the studied experimental range. Under the optimal condition（initial p H value of 2.0, pulp density of 1.59%, and initial concentration of ferrous ions of 0 g/L）, the total copper extraction predicted by the model is 85.98% which is significantly close to that obtained from the experiment（84.57%）. The results show that RsM could be useful to predict the maximum copper extraction from a low-grade ore and investigate the effects of variables on the final response. Besides, a couple of statistically significant interactions are derived between p H value and pulp density as well as p H value and initial ferrous ion concentration which are precisely interpreted. However, there is no statistically significant interaction between the initial ferrous ion concentration and the pulp density. Additionally, the response at optimal levels of p H value and pulp density is found to be independent on the level of initial ferrous concentration.

关键词： modeling optimization bacterial leaching response surface methodology copper extraction copper ore

Dynamics of a rotating ring-stiffened sandwich conical shell with an auxetic honeycomb core

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 963-982页

作者： s.JAHANGIRI A.GHORBANPOUR ARANI z.KHODDAMI MARAGHI Department of solid Mechanics Faculty of Mechanical EngineeringUniversity of KashanKashan ***Iran Faculty of Engineering Mahallat Institute of Higher EducationMahallat ***Iran

The free vibration analysis of a rotating sandwich conical shell with a reentrant auxetic honeycomb core and homogenous isotropic face layers reinforced with a ring support is *** shell is modeled utilizing the first-order shear deformation theory(FsDT)incorporating the relative,centripetal,and Coriolis accelerations alongside the initial hoop tension created by the *** governing equations,compatibility conditions,and boundary conditions are attained using Hamilton’s *** trigonometric functions,an analytical solution is derived in the circumferential direction,and a numerical one is presented in the meridional direction via the differential quadrature method(DQM).The effects of various factors on the critical rotational speeds and forward and backward frequencies of the shell are *** present work is the first theoretical work regarding the dynamic analysis of a rotating sandwich conical shell with an auxetic honeycomb core strengthened with a ring support.

关键词： free vibration conical shell rotating shell ring support auxetic honeycomb

Probing the Bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

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Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： s R Wu B Q Wang z W Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric Bardeen-Kiselev black hole(BH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the Bardeen-Kiselev BH with the cosmological constant due to electromagnetic and gravitational *** varying the BH parameters,we discuss the behavior of both real and imaginary parts of the BH quasinormal frequencies and compare these frequencies with the Reissner-Nordström-de sitter BH surrounded by quintessence(RN-dsQ).Interestingly,it is shown that the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dsQ under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dsQ are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the Bardeen-Kiselev BH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the Bardeen-Kiselev BH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors Bardeen-Kiselev black hole with cosmological constant

Construction of 2D/2D Ti_(3)C_(2)T_(x)MXene/Cds heterojunction with photothermal effect for efficient photocatalytic hydrogen production

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Journal of Materials science & Technology 2024年第4期171卷 1-9页

作者： T.Y.Huang z.Yang s.Y.Yang z.H.Dai Y.J.Liu J.H.Liao G.Y.zhong z.J.Xie Y.P.Fang s.s.zhang Key Laboratory for Biobased Materials and Energy of Ministry of Education Guangdong Laboratory for Lingnan Modern AgricultureCollege of Materials and EnergySouth China Agricultural UniversityGuangzhou 510643China school of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China school of Chemical Engineering and Energy Technology Guangdong Provincial Key Laboratory of Distributed Energy SystemsDongguan University of TechnologyDongguan 523808China

The insensitivity of semiconductors to visible and infrared light is a key constraint on the utilization of light energy in photocatalytic *** photocatalysts with full-spectrum absorption through surface engineering is an effective approach to fully harnessing light energy in semiconductor ***,a novel stable Ti_(3)C_(2)T_(x)MXene/Cds heterojunction catalyst is obtained by in-situ epitaxial growth of two-dimensional(2D)Cds nanosheets on 2D MXene interface via a solvothermal *** exceptional light absorption properties of MXene confer outstanding full-spectrum driven photocat-alytic hydrogen evolution capability upon the heterogeneous *** unique 2D/2D structure effectively mitigated the recombination of photogenerated carriers,enhancing the photocatalytic performance of the ***,the composite catalyst exhibits a significantly higher surface temperature of 80.4℃under visible light irradiation at an intensity of 0.1 W/cm^(2),which is 1.84 times higher than that of *** irradiation of visible and near infrared light,the composite catalyst with photothermal ef-fect demonstrates a remarkable hydrogen evolution rate of 65.4 mmol g^(-1)h^(-1),which is 7.2 times higher than that of Cds *** study introduces a novel approach for constructing full-spectrum absorption catalysts and expands the application of the photothermal effect in photocatalytic hydrogen evolution research.

关键词： Two-dimensional structure Heterostructure Photothermal effect Photocatalyst Hydrogen evolution

Four Late-type Galaxies with Double Radio Lobes and Properties of such Galaxies

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Research in Astronomy and Astrophysics 2024年第4期24卷 84-90页

作者： z.s.Yuan X.Y.Gao z.L.Wen J.L.Han National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China CAs Key Laboratory of FAsT National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China school of Astronomy and space sciences University of Chinese Academy of SciencesBeijing 100049China

The triggering mechanism for radio lobes from late-type galaxies is not fully *** samples are desired for a thorough investigation and *** utilizing the optical data from the newly released Dark Energy spectroscopic Instrument imaging surveys and the radio sources from the NRAO VLA sky survey and the Faint Images of the Radio sky at Twenty-centimeter,we identify four Late-type Galaxies with double Radio Lobes(La GRLs):J0217-3645,J0947+6220,J1412+3723 and J1736+*** previously known La GRLs,we confirm the correlation between radio power P_(1.4GHz)and stellar mass M_(*)of host ***(25/35)La GRLs belong to the blue cloud galaxies,while the newly identified cases in this work are located within the region of the red *** find a clear correlation between the differential radio power,i.e.,the offset from the P_(1.4GHz)-M_(*)relation,and the galaxy color,indicating that bluer galaxies at a fixed M_(*)tend to host more powerful radio ***,the majority(31/36)of La GRLs are either located in a galaxy group or displaying a disturbed *** suggest that all of the galaxy mass,color and surrounding environment could play important roles in triggering radio lobes in late-type galaxies.

关键词： galaxies:active galaxies:jets galaxies:spiral radio continuum:galaxies

An Improved Image steganography security and Capacity Using Ant Colony Algorithm Optimization

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Computers, Materials and Continua 2024年第3期80卷 4643-4662页

作者： Jasim z.K.J. Kurnaz s. Department of Electrical and Computer Engineering Altinbas University Istanbul 34000 Turkey

This advanced paper presents a new approach to improving image steganography using the Ant Colony Optimization (ACO) algorithm. Image steganography, a technique of embedding hidden information in digital photographs, should ideally achieve the dual purposes of maximum data hiding and maintenance of the integrity of the cover media so that it is least suspect. The contemporary methods of steganography are at best a compromise between these two. In this paper, we present our approach, entitled Ant Colony Optimization (ACO)-Least significant Bit (LsB), which attempts to optimize the capacity in steganographic embedding. The approach makes use of a grayscale cover image to hide the confidential data with an additional bit pair per byte, both for integrity verification and the file checksum of the secret data. This approach encodes confidential information into four pairs of bits and embeds it within uncompressed grayscale images. The ACO algorithm uses adaptive exploration to select some pixels, maximizing the capacity of data embedding while minimizing the degradation of visual quality. Pheromone evaporation is introduced through iterations to avoid stagnation in solution refinement. The levels of pheromone are modified to reinforce successful pixel choices. Experimental results obtained through the ACO-LsB method reveal that it clearly improves image steganography capabilities by providing an increase of up to 30% in the embedding capacity compared with traditional approaches; the average Peak signal to Noise Ratio (PsNR) is 40.5 dB with a structural Index similarity (ssIM) of 0.98. The approach also demonstrates very high resistance to detection, cutting down the rate by 20%. Implemented in MATLAB R2023a, the model was tested against one thousand publicly available grayscale images, thus providing robust evidence of its effectiveness. Copyright © 2024 The Authors. Published by Tech science Press.

关键词： ant colony algorithm capacity optimization steganalysis steganography

Ghost-YOLO v8: An Attention-Guided Enhanced small Target Detection Algorithm for Floating Litter on Water surfaces

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Computers, Materials and Continua 2024年第3期80卷 3713-3731页

作者： Huangfu z. Li s. Yan L. school of Information Engineering North China University of Water Resources and Electric Power Zhengzhou 450046 China

Addressing the challenges in detecting surface floating litter in artificial lakes, including complex environments, uneven illumination, and susceptibility to noise and weather, this paper proposes an efficient and lightweight Ghost-YOLO (You Only Look Once) v8 algorithm. The algorithm integrates advanced attention mechanisms and a small-target detection head to significantly enhance detection performance and efficiency. Firstly, an sE (squeeze-and-Excitation) mechanism is incorporated into the backbone network to fortify the extraction of resilient features and precise target localization. This mechanism models feature channel dependencies, enabling adaptive adjustment of channel importance, thereby improving recognition of floating litter targets. secondly, a 160 × 160 small-target detection layer is designed in the feature fusion neck to mitigate semantic information loss due to varying target scales. This design enhances the fusion of deep and shallow semantic information, improving small target feature representation and enabling better capture and identification of tiny floating litter. Thirdly, to balance performance and efficiency, the GhostConv module replaces part of the conventional convolutions in the feature fusion neck. Additionally, a novel C2fGhost (CsPDarknet53 to 2-stage Feature Pyramid Networks Ghost) module is introduced to further reduce network parameters. Lastly, to address the challenge of occlusion, a new loss function, WIoU (Wise Intersection over Union) v3 incorporating a flexible and non-monotonic concentration approach, is adopted to improve detection rates for surface floating litter. The outcomes of the experiments demonstrate that the Ghost-YOLO v8 model proposed in this paper performs well in the dataset Marine, significantly enhances precision and recall by 3.3 and 7.6 percentage points, respectively, in contrast with the base model, mAP@0.5 and mAP 0.5:0.95 improve by 5.3 and 4.4 percentage points and reduces the computational volu

关键词： attention mechanism ghostnet loss function small target detection head surface floating litter target detection YOLO v8