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Impact of crystalline and amorphous iron-and aluminum hydroxides on mechanisms of phosphate adsorption and desorption

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Journal of Environmental Sciences 2018年第8期30卷 175-189页

作者： Stella Gypser Florian Hirsch Anja m.Schleicher Dirk Freese Brandenburg University of Technology Cottbus-Senftenberg Faculty of Environment Process Engineering Biotechnology and Chemistry Department of Soil Protection and Recultivation Brandenburg University of Technology Cottbus-Senftenberg Faculty of Environment Process Engineering Biotechnology and Chemistry Department of Geopedology and Landscape Development German Research Centre for Geosciences Section 3.1 Inorganic and Isotope Geochchemistry

Fourier-transform infrared（FT-IR） spectroscopic experiments were carried out during phosphate adsorption on highly crystalline gibbsite, poorly crystalline 2-line-ferrihydrite and amorphous iron–aluminum–hydroxide mixtures in the molar ratio 1：0, 10：1, 5：1, 1：1, 1：5, 1：10 and 0：1. The OH stretching vibrational bands were utilized to analyze changes in structural and surface OH groups during adsorption, because the position of characteristic P／O vibrational bands can shift depending on reaction conditions, pH or adsorbed phosphate *** and desorption kinetics were studied at pH6 and different initial phosphate concentrations to achieve varying phosphate coverage on the mineral surfaces. For gibbsite the formation of AlHPO4 and Al2HPO4 can be assumed, while for ferrihydrite, a FeHPO4 or Fe2PO4 complex and the precipitation of FePO4 with longer equilibration time were ***2HPO4 or a Fe2PO4 surface complex was deduced for Fe-hydroxides, an AlH2PO4 surface complex was identified for Al-hydroxide, and both displayed either hydrogen bonds to neighboring hydroxyl groups or hydrogen bonds to outer-sphere complexes. Fe：Al-hydroxide mixtures with high Al ratios showed a low phosphate desorption rate, while ferrihydrite and the Fe：Al-hydroxide mixtures with high Fe ratios had almost negligible desorption rates. It was concluded that within the weakly associated amorphous FeO（OH） materials, FePO4 precipitated, which was bound by outer-sphere hydrogen bonds. With high Al ratios, desorption increased, which indicated weaker phosphate binding of both inner-sphere and outer-sphere complexes and hence, either no or minor quantities of precipitate. Ferrihydrite showed a more rigid structure and a lower extent of precipitation compared to amorphous Fe-hydroxide.

关键词： Phosphate Adsorption Desorption Surface complexation Precipitation FT-IR

Greedy nonlinear autoregression for multifidelity computer models at different scales

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Energy and AI 2020年第1期1卷 117-130页

作者： W.Xing m.Razi R.m.Kirby K.Sun A.A.Shah School of Energy and Power Engineering Chongqing University174 ShazhengjieShapingbaChongqing 400044China Scientific Computing and Imaging Institute University of Utah72 S Central Campus DriveRoom 3750 Salt Lake CityUT 84112United States

Although the popular multi-fidelity surrogate models,stochastic collocation and nonlinear autoregression have been applied successfully to multiple benchmark problems in different areas of science and engineering,they have certain *** propose a uniform Bayesian framework that connects these two methods allowing us to combine the strengths of *** this end,we introduce Greedy-NAR,a nonlinear Bayesian autoregressive model that can handle complex between-fidelity correlations and involves a sequential construction that allows for significant improvements in performance given a limited computational *** proposed enhanced nonlinear autoregressive method is applied to three benchmark problems that are typical of energy applications,namely molecular dynamics and computational fluid *** results indicate an increase in both prediction stability and accuracy when compared to those of the standard multi-fidelity autoregression *** results also reveal the advantages over the stochastic collocation approach in terms of accuracy and computational *** speaking,the proposed enhancement provides a straightforward and easily implemented approach for boosting the accuracy and efficiency of concatenated structure multi-fidelity simulation methods,e.g.,the nonlinear autoregressive model,with a negligible additional computational cost.

关键词： multi-fidelity models Autoregressive Gaussian processes Deep Gaussian processes Surrogate models molecular dynamics Computational fluid dynamics

Diffusion monte Carlo calculations on LaB molecule

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Chinese Physics B 2018年第9期27卷 241-246页

作者： Nagat Elkahwagy Atif Ismail S m A maizet K R mahmoud Department of Physics Faculty of Science Kafrelsheikh University Kafr El-Sheikh Egypt Department of Physics Faculty of Applied Sciences Umm AI Qura University Makkah Saudi Arabia Department of Physics Faculty of Science Menoufia University Shebin EI-Kom Egypt

Potential energy curves for the lowest electronic states of LaB and LaB- have been calculated by ab initio *** diffusion monte Carlo method has been employed in combination with three different trial functions. Spectroscopic constants have also been numerically derived for the neutral molecule and compared with the only available theoretical work;^（[19]） however, predictions are provided for the corresponding constants for the anionic species which have not been reported yet. Our calculations suggest the high spin quintet state of LaB as the ground state with the triplet state higher in energy irrespective of the type of the functional used. This suggestion is in good accordance with the previous theoretical results calculated at B3LYP/LANL2DZ level of theory, whereas it contradicts with the prediction based upon B3LYP/SDD calculations in the same study. moreover, variations of the permanent dipole moments as a function of the internuclear separations for the two electronic states of the neutral molecule have been studied and analyzed.

关键词： potential energy curve lanthanum boride diffusion monte Carlo dipole moment

Characterization of refractory behaviour of complex gold/silver ore by diagnostic leaching

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中国有色金属学会会刊：英文版 2009年第3期19卷 707-713页

作者： O. CELEP . ALP H. DEVEC m. VICIL mining Engineering Department Karadeniz Technical University Geology Engineering Department Karadeniz Technical University

The amenability of a refractory ore to the extraction of gold and silver by cyanide leaching was investigated. Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The leaching tests show that the extraction of gold and silver is consistently low, i.e. ≤47% and ≤19.2%, respectively, over a leaching period of 24 h. Even fine grinding (e.g. m) does not improve the recovery of gold and silver. Diagnostic leaching approach provides information into the cause of the refractoriness of the ore. The findings suggest that the refractoriness is induced by the dissemination and encapsulation of the very fine gold and silver particles largely in the carbonates, oxides and sulfides and, to a small extent, with silicates present in the ore matrix. These findings highlight the practical importance of diagnostic leaching for the understanding of the refractory characteristic of such an ore and for the identification of possible pretreatment options to overcome its refractoriness prior to cyanide leaching.

关键词：氰化浸出银矿石黄金诊断行为表征浸出试验硅酸盐矿石

Effect of TiN Particles and Grain Size on the Charpy Impact Transition Temperature in Steels

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Journal of materials Science & Technology 2012年第10期28卷 878-888页

作者： J.Du m.Strangwood C.L.Davis School of metallurgy and materials University of Birmingham

The toughness of ferritic steels is influenced by the grain size distribution, second phase, precipitates and coarse inclusions. In this work an examination of the effect of coarse TiN particles （〉0.5 μm） and ferrite grain size on the Charpy impact transition temperature in high strength low alloyed steels has been carried out. Steels with high Ti content （up to 0.045 wt%）, have been heat-treated and furnace cooled to obtain a ferrite-pearlite microstructure with different ferrite grain sizes. Coarse TiN particle size and ferrite grain size distributions have been measured and Charpy impact testing has been carried out. Scanning electron microscopy （SEm） analysis has been used to measure the grain boundary carbide thickness and to determine if the coarse TiN particles are acting as cleavage initiation sites by fractographic analysis. The Charpy ductile-brittle transition temperatures （DBTT） have been predicted using standard literature equations, and compared to the measured values. The relationship between the ferrite grain size and coarse TiN particle size and number density in terms of whether the coarse TiN particles act as effective cleavage initiation sites is discussed in this paper.

关键词： TiN particles Grain size Charpy impact test Ductile-brittle transitiontemperatures (DBTT) Steels

CFD modeling of a spouted bed with a porous draft tube

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Particuology 2010年第5期8卷 415-424页

作者： Salar Azizi Seyyed Hossein Hosseini m.moraveji Goodarz Ahmadi Chemical Engineering Department Faculty of EngineeringArak University Department of Chemical Engineering Faculty of EngineeringIlam University Department of mechanical and Aeronautical Engineering Clarkson University

Spouted bed with a porous draft tube is used for drying of grains and chemical products and thermal disinfestations process. This work provides a computational fluid dynamics （CFD） simulation of binary mixtures of glass particles in a spouted bed with a porous draft tube. The simulation used the multi-fluid Eulerian-Eulerian approach based on kinetic theory of granular flows, incorporating a kinetic-frictional constitutive model for dense assemblies of particulate solids and Gidaspow＇s drag model for the interaction between gas and particles. Influences of solids mass fraction and inlet gas flow rate on pressure distribution, gas and particle velocities were studied. The modeling results were compared with the exper- imental work of Ishikura, Nagashima, and Ide （2003） for the flow condition along the axis of the spouted bed. Good agreement between the modeling results and experimental data was observed.

关键词： Spouted bedPorous dra tubeHydrodynamicsKinetictheoryCFD

Future for inertial-fusion energy in Europe:a roadmap

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High Power Laser Science and Engineering 2023年第6期11卷 162-192页

作者： Dimitri Batani Arnaud Colaitis Fabrizio Consoli Colin N.Danson Leonida Antonio Gizzi Javier Honrubia Thomas Kühl Sebastien Le Pape Jean-Luc miquel Jose manuel Perlado R.H.H.Scott michael Tatarakis Vladimir Tikhonchuk Luca Volpe Centre Lasers Intenses et Applications(CELIA) Universitéde Bordeaux±CNRS±CEATalence cedexFrance ENEA Fusion and Technology for Nuclear Safety and Security DepartmentC.R.FrascatiFrascatiItaly AWE AldermastonReadingUK Centre for Inertial Fusion Studies Blackett LaboratoryImperial College LondonLondonUK Istituto Nazionale di Ottica Consiglio Nazionale delle Ricerche(CNR-INO)PisaItaly ETSIAE Universidad Politecnica de madrid MadridSpain GSI-Helmholtzzentrum für Schwerionenforschung GmbH DarmstadtGermany Laboratoire pour l’Utilisation des Lasers Intenses(LULI) CNRS±Ecole PolytechniquePalaiseau cedexFrance ALP Le BarpFrance and CEA/DAMÎle de FranceBruyères le ChâtelArpajon cedexFrance Instituto Fusión NuclearªGuillermo Velardeº(IFN-GV) Universidad Politecnica de MadridMadridSpain Central Laser Facility STFC Rutherford Appleton LaboratoryHarwell OxfordOxfordshireUK Institute of Plasma Physics and Lasers University Research and Innovation CentreHellenic Mediterranean UniversityRethymnoCreteGreece Department of Electronic Engineering School of EngineeringHellenic Mediterranean UniversityChaniaCreteGreece Extreme Light Infrastructure ERIC ELI-Beamlines FacilityDolníBÏrežanyCzech Republic Centro de Laseres Pulsados(CLPU) Parque CientificoVillamayorSalamancaSpain

The recent achievement of fusion ignition with laser-driven technologies at the National Ignition Facility sets a historic accomplishment in fusion energy *** accomplishment paves the way for using laser inertial fusion as a viable approach for future energy *** has a unique opportunity to empower research in this field internationally,and the scientific community is eager to engage in this *** propose establishing a European programme on inertial-fusion energy with the mission to demonstrate laser-driven ignition in the direct-drive scheme and to develop pathway technologies for the commercial fusion *** proposed roadmap is based on four complementary axes:(ⅰ)the physics of laser-plasma interaction and burning plasmas;(ⅱ)high-energy high repetition rate laser technology;(ⅲ)fusion reactor technology and materials;and(ⅳ)reinforcement of the laser fusion community by international education and training *** foresee collaboration with universities,research centres and industry and establishing joint activities with the private sector involved in laser *** project aims to stimulate a broad range of high-profile industrial developments in laser,plasma and radiation technologies along with the expected high-level socio-economic impact.

关键词： education and training fusion reactor technology high-energy laser high repetition rate laser inertial confinement fusion laser-plasma interaction public-private partnership radiation resistant materials

Developing a two-decadal time-record of rice field maps using Landsat-derived multi-index image collections with a random forest classifier:A Google Earth Engine based approach

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Information Processing in Agriculture 2024年第2期11卷 260-275页

作者： W.Ashane m.Fernando I.P.Senanayake Department of Nano Science Technology Wayamba University of Sri LankaKuliyapitiya 60200Sri Lanka Dchoolf Engineing CllegeoEngineeringSience and EnionmentThe UniversyewcastleCallaghanW2Austraia

Historic maps showing the temporal distribution of rice fields are important for precision agriculture,irrigation optimisation,forecasting crop yields,land use management and formulating ***,mapping rice felds using traditional ground surveys is impractical when high cost,time and labour requirements are considered,and the availability of such detailed records is *** satellite remote sensing appears to be a viable solution,conventional segmentation and classification methods with spectral bands are often unable to contrast the distinct characteristics between rice fields and other vegetation *** this end,we explored a novel,Google Earth Engine(GEE)based multiindex random forest(RF)classification approach to map rice fields over two *** images from 2000 to 2020 of two Sri Lankan rice cultivation districts were extracted from GEE and a multi-index RF classification algorithm was applied to distinguish the rice *** results showed above 80%accuracy for both training and validation,when compared against high spatial resolution Google Earth *** essence,multi-index sampling and RF together synergised the compelling classifcation accuracy by effectively capturing vegetation,water(ponding)and soil characteristics unique to the rice felds using a single-click *** maps developed in this study were further compared against the mODIS land cover type product(mCD12Q1)and the corresponding superior statistics on rice fields demonstrated the robustness of the proposed *** work seeking effective index combinations is recommended,and this approach can potentially be extended to other crop analyses elsewhere.

关键词： Google Earth Engine(GEE) Image classification Random forest mapping rice fields Time series analysis Vegetation index

Effects of Plasticizers,Antioxidants and Burning Rate modifiers on Aging Performance of the HTPB/HmDI Composite Solid Propellant

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含能材料 2019年第1期27卷 21-27,90页

作者： Ahmed m Enew Ehab Abadir Sahar Elmarsafy Karim K Elsharkawy Chemical Department Faculty of EngineeringCairo University School of Chemistry and Environment Beijing University of Aeronautics and Astronautics

The effects of plasticizers,antioxidants and burning rate modifiers on the aging performance of the composite solid propellant based on hydroxyl-terminated polybutadiene(HTPB)/hexamethylene diisocyanate(HmDI)were explored by apply-ing an accelerated aging program for 90 day at 70 ℃. The HTPB propellant matrix with the diisooctyl sebacate(DOS)as plasti-cizers and diisooctyl azelate(DOZ), antioxidants as N,N ′-Diphenyl-p-phenylenediamine(AO) and 2,2′-methylenebis(4-methyl-6-tert-butylphenol)(cyanox 2246)and burning rate modifiers as barium ferrite(BF),copper chromites(CC)and fer-ric oxide(FO)were varied. Results show that sample(S1)which based on DOS decreases the stress value and increases the strain value which considered to be an excellent start for aging program. Sample(S3)containing AO presents the higher resis-tance to oxidation showing the better performance that reflects on increasing the shelf life of the composite solid propellant mo-tor. Sample(S5)which based on BF enhances the ballistic performance among over the other tested two samples. The accelerat-ed aging program allowed us to estimate the motor in-service lifetime.

关键词： polybutadiene(HTPB)/hexamethylene diisocyanate(HmDI)composite solid propellant plasticizers antioxidants burning rate modifiers aging program