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Effect of salinity and acidity on bioleaching activity of mesophilic and extremely thermophilic bacteria

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中国有色金属学会会刊：英文版 2008年第3期18卷 714-721页

作者： H.DEVECi m.A.JORDAn n.POWELL i.ALP Department of mining Engineering Karadeniz Technical UniversityTrabzon 61080Turkey Camborne School of mines UECTremough CampusPenrynCornwallTR109EZUK

The effects of bacterial strain, salinity and pH on the bioleaching of a complex ore using mesophilic and extremely thermophilic bacteria were investigated and the statistical analysis of the results was performed using ERGUn’s test. The extreme thermophiles were shown to display superior kinetics of dissolution of zinc compared with the mesophiles as confirmed by the statistical analysis. Bioleaching performance of the extreme thermophiles is found to improve in response to the increase in acidity (pH from 2.0 to 1.0) whilst the activity of the mesophiles is adversely affected by decreasing pH. Statistical analysis of the bioleaching data indicates that the effect of pH is insignificant in the range of pH 1.0-1.2 for the extreme thermophiles and pH 1.4-2.0 for the mesophiles. Salinity is shown to have a suppressing effect on the mesophiles. However, the extreme thermophiles appear to be halophilic in character as they could operate efficiently under saline conditions (1%-4%Cl- (w/v)).

关键词：细菌生物浸取盐度 pH 硫化物

Dibaryon resonances and short-range nn interaction

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Chinese Physics C 2022年第11期46卷 238-261页

作者： V.i.Kukulin V.n.Pomerantsev O.A.Rubtsova m.n.Platonova i.T.Obukhovsky Skobeltsyn institute of nuclear Physics Lomonosov Moscow State UniversityLeninskie Gory 1/2119991 MoscowRussia

The dibaryon concept for nuclear force is presented,assuming that the attraction between nucleons at medium distances is mainly due to the s-channel exchange of an intermediate six-quark(dibaryon)*** construct the respective nn interaction model,a microscopic six-quark description of the nn system is used,in which symmetry aspects play a special *** is shown that the nn interaction in all important partial waves can be described by the superposition of long-range t-channel one-pion exchange and s-channel exchange by an intermediate *** model developed in this study provides a good description of both elastic phase shifts and inelasticities of nn scattering in all S,P,D,and F partial waves at energies from zero to 600-800 meV and even *** parameters of the intermediate six-quark states,corresponding to the best fit of nn scattering data,are found to be consistent with the parameters of the known dibaryon resonances in those nn partial configurations,where their existence has been experimentally *** for new dibaryon states are given as well.

关键词： nucleon-nucleon interaction dibaryon resonances short-range nuclear force

mobility of Arsenic and Heavy metals in a Sandy-Loam Textured and Carbonated Soil

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Pedosphere 2009年第2期19卷 166-175页

作者： i. GARC íA m. DiEZ F. mART ín m. Simón C. DORROnSORO Departamento Edafologia y Quimica Agricola CITE IIB Carretera Sacramento s/n 04120 University of Almeria (Spain) Departamento Edafologia y Quimica Agricola Campus Fuentenueva s/n 18002 University of Granada (Spain)

The continued effect of the pyrite-tailing oxidation on the mobility of arsenic, lead, zinc, cadmium, and copper was studied in a carbonated soil under natural conditions, with the experimental plot preserved with a layer of tailing covering the soil during three years. The experimental area is located in Southern Spain and was affected by a pyrite-mine spill. The climate in the area is typically mediterranean, which determines the rate of soil alteration and elem.nt mobility. The intense alteration processes that occurred in the soil during three years caused important changes in its morphology and a strong degradation of the main soil properties. in this period, lead concentrated in the first 5 mm of the soil, with concentrations higher than 1500 mg kg?1, mainly associated to the neoformation of plumbojarosite. Arsenic was partially leached from the first 5 mm and mainly concentrated between 5–10 mm in the soil, with maximum values of 1239 mg kg-1; the retention of arsenates was related to the neoformation of iron hydroxysulfates (jarosite, schwertmannite) and oxyhydroxides (goethite, ferrihydrite), both with a variable degree of crystallinity. The mobility of Zn, Cd, and Cu was highly affected by pH, producing a stronger leaching in depth; their retention was related to the forms of precipitated aluminium and, in the case of Cu, also to the neoformation of hydroxysulfate.

关键词： arsenic heavy metals oxidation pyrite-tailing soil

Framing Shaping Outcomes:issues Related to mitigation in the UnFCCC negotiations

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Fudan Journal of the Humanities and Social Sciences 2020年第3期13卷 375-394页

作者： m.n.i.Sorkar Fudan University ShanghaiChina Dhaka Bangladesh

Actors purposefully frame up their issues in multilateral negotiations to reach their desired *** were the issues related to mitigation framed up during the two decades of climate negotiations that yielded the Paris Agreem.nt,what was the mechanism for the evolution of the frames and why did only certain crucially contested frames find traction?in these quests,this work conducts a simultaneous content and frame analysis by applying the framing theory and maps the historic evolution pathways of the related *** qualitative analysis identifies a process of frame generation through the contested rhetoric framing by the actors,in line with their primary logics which were shaped by their mental *** finds that the act of framing was the sine-qua-non for the sustenance and traction of the issues,but the fates of the crucially contested frames were determined by the powerful *** the concept of framing allows the systematic visualization of the negotiation process related to Greenhouse Gas mitigation at the annual conferences of the United nations Framework Convention on Climate Change and helps explain how and why certain outcomes appeared.

关键词： Climate negotiations Framing GHG mitigation Paris Agreem.nt Process tracing

Kinetics and mechanism of oxidation for nickel-containing pyrrhotite tailings

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international Journal of minerals,metallurgy and materials 2021年第9期28卷 1469-1477页

作者： Alexander m.Klyushnikov Rosa i.Gulyaeva Evgeniy n.Selivanov Sergey m.Pikalov institute of metallurgy of the Ural branch of the Russian Academy of Sciences Yekaterinburg 620016Russia

X-ray powder diffraction,scanning electron microscopy,energy dispersive spectroscopy,thermogravimetry,differential scanning calorimetry,and mass spectrometry have been used to study the products of nickel-containing pyrrhotite tailings oxidation by oxygen in the *** kinetic triplets of oxidation,namely,activation energy(E_(a)),pre-exponential factor(A),and reaction model(f(α))being a function of the conversion degree(α),were adjusted by regression *** case of a two-stage process representation,the first step proceeds under autocatalysis control and ends atα=*** kinetic triplet in the first step is E_(a)=262.2 kJ/mol,lg A=14.53 s^(−1),and f(α)=(1-α)^(4.11)(1+1.51×10^(-4)α).For the second step,the process is controlled by the two-dimensional diffusion of the reactants in the layer of oxidation *** kinetic triplet in the second step isЕa=215.0 kJ/mol,lg A=10.28 s^(−1),and f(α)=(-ln(1-α))^(-1).The obtained empirical formulae for the rate of pyrrhotite tailings oxidation reliably describe the macro-mechanism of the process and can be used to design automatization systems for roast-ing these materials.

关键词： pyrrhotite tailings oxidation thermogravimetry kinetics mechanism

investigations of mechanical, electronic, and magnetic properties of non-magnetic mgTe and ferro-magnetic mg_(0.75)T m_(0.25)Te (Tm = Fe, Co, ni): An ab-initio calculation

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Chinese Physics B 2016年第4期25卷 303-313页

作者： mahmood Q Alay-e-Abbas S m mahmood i Asif mahmood noor n A Department of Physics University of the Punjab Quaid-e-Azam Campus Department of Physics Government College University Faisalabad Department of Physics University of Sargodha Centre for High Energy Physics University of the Punjab Quaid-e-Azam Campus College of Engineering Chemical Engineering Department King Saud University

The mechanical, electronic and magnetic properties of non-magnetic mgTe and ferro-magnetic （Fm） mgo.75 Tm025 Te （Tm = Fe, Co, ni） in the zinc-blende phase are studied by ab-initio calculations for the first time. We use the generalized gradient approximation functional for computing the structural stability, and mechanical properties, while the modified Becke and Johnson local （spin） density approximation （mBJLDA） is utilized for determining the electronic and magnetic properties. By comparing the energies of non-magnetic and Fm calculations, we find that the compounds are stable in the Fm phase, which is confirmed by their structural stabilities in terms of enthalpy of formation. Detailed descriptions of elastic properties of mgo.75Tmo.25Te alloys in the Fm phase are also presented. For electronic properties, the spin- polarized electronic band structures and density of states are computed, showing that these compounds are direct bandgap materials with strong hybridizations of Tm 3d states and Te p states. Further, the ferromagnetism is discussed in terms of the Zener free electron model, RKKY model and double exchange model. The charge density contours in the （110） plane are calculated to study bonding properties. The spin exchange splitting and crystal field splitting energies are also calculated. The distribution of electron spin density is employed in computing the magnetic moments appearing at the magnetic sites （Fe, Co, ni）, as well as at the non-magnetic sites （mg, Te）. it is found that the p-d hybridization causes not only magnetic moments on the magnetic sites but also induces negligibly small magnetic moments at the non-magnetic sites.

关键词： FP-LAPW + lo elastic parameters spin polarized electronic properties magnetic properties

Structural, elastic and electronic properties for m_2 XC (m=Ti and Cr, X=Ga and Al) phases from ab initio calculations

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Acta metallurgica Sinica(English Letters) 2011年第4期24卷 255-270页

作者： B. Ghebouli m.A. Ghebouli m. Fatmi n. Bouarissa m. Benkerri i.A. ibrahim Laboratory of Study of Surfaces and interfaces of Solids materials Department of Physics Faculty of Science University of Setif Department of Physics University Center Research Unit on emerging materials Ferhat Abbas University of Setif Department of Physics Faculty of Sciences King Khalid University Central metallurgical Research and Development institute P.O. Box: 87 Helwan 11424 Cairo Egypt

The first-principles study of the structural, elastic and electronic properties of the m2XC phases depending on the type of m transition metal （m are Ti and Cr） and on X （X are Ga and A1） was reported. The calculations are performed using the pseudo-potential plane-wave approach in both the local density and generalized gradient approximations. The elastic constants are calculated using the static finite strain technique. Features such as structural and elastic parameters, Debye tem- perature, sound velocities and their pressure dependence have been investigated. in agreem.nt with experimental and previous theoretical findings, it is found that the compressibility along a and c axis depends on the valence electron concentration （VEC）. Correlations revealing the governing role of the X and m elem.nts on the machinability indices of the material have been examined. The electronic properties have been discussed in terms of chemical bonding showing that bonding is due to md-Cp and md-Xp hybridizations. m-C bonds are stiffer than m-X ones and A1-Ti （Cr-C） bonds are stiffer than those corresponding to Ti-C （A1-Cr）. it is shown that the stiffness of the m-X and m-C bonds increases with increasing the number of VEC.

关键词： m2XC phases ab initio Pressure effect Band structures

Recent advances in catalytic systems for CO_(2) conversion to substitute natural gas(SnG):Perspective and challenges

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Journal of Energy Chemistry 2021年第11期30卷 377-407,I0008页

作者： i.Hussain A.A.Jalil n.S.Hassan m.Y.S.Hamid Department of Chemistry Faculty of ScienceUniversiti Teknologi Malaysia81310 UTM Johor BahruJohorMalaysia School of Chemical and Energy Engineering Faculty of EngineeringUniversiti Teknologi Malaysia81310 UTM Johor BahruJohorMalaysia Centre of Hydrogen Energy Institute of Future Energy81310 UTM Johor BahruJohorMalaysia

it has been well established that carbon dioxide(CO_(2))is one of the main greenhouse gasses and a leading driver of climate *** chemical conversion of CO_(2) to substitute natural gas(SnG)in the presence of renewable hydrogen is one of the most promising solutions by a well-known process called CO_(2) *** have been comprehensive efforts in developing effective and efficient CO_(2) methanation catalytic ***,the choice of competitive and stable catalysts is still a monumental obstruction and a great challenge towards the commercialization and industrialization of CO_(2) *** is necessary to emphasize the critical understandings of intrinsic and extrinsic interactions of catalyst components(active metal,support,promoter,etc.)for enhanced catalytic performance and stability during CO_(2) *** study reviews the up-to-date developments on CO_(2) methanation catalysts and the optimal synergistic relationship between active metals,support,and promoters during the catalytic *** existing catalysts and their novel properties for enhanced CO_(2) methanation were elucidated using the state-of-the-art experimental and theoretical *** selection of an appropriate synthesis method,catalytic activity for CO_(2) methanation,deactivation of the catalysts,and reaction mechanisms studies,have been explicitly compared and ***,future efforts should be directed towards the sustainable developments of catalytic configurations for successful industrial applications of CO_(2) utilization to SnG using CO_(2) methanation.

关键词： CO_(2)utilization CO_(2)methanation SnG Catalytic systems Deactivation mechanism

mHD stagnation-point flow and heat transfer towards stretching sheet with induced magnetic field

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Applied mathematics and mechanics(English Edition) 2011年第4期32卷 409-418页

作者： F.m.ALi R.nAZAR n.m.ARiFin i.POP Department of mathematics Institute of Mathematical ResearchUniversiti Putra Malaysia School of mathematical Sciences Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia Faculty of mathematics University of Cluj

The problem of the steady magnetohydrodynamic （mHD） stagnation-point flow of an incompressible viscous fluid over a stretching sheet is studied. The effect of an induced magnetic field is taken into account. The nonlinear partial differential equations are transformed into ordinary differential equations via the similarity transformation. The transformed boundary layer equations are solved numerically using the shooting method. numerical results are obtained for various magnetic parameters and Prandtl numbers. The effects of the induced magnetic field on the skin friction coefficient, the local nusselt number, the velocity, and the temperature profiles are presented graphically and discussed in detail.

关键词： boundary layer heat transfer induced magnetic field numerical solution magnetohydrodynamic (mHD) flow stretching sheet