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Adsorption of yttrium(Y^(3+)) and concentration of rare earth elements from phosphogypsum using chitin and chitin aerogel

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Journal of Rare Earths 2024年第4期42卷 775-782页

作者： Glaydson S.dos reis Diana Pinto Sabrina F.Lütke Eder c.Lima Luis F.O.Silva Irineu A.S.De Brum Guilherme L.Dotto Department of Forest Biomaterials and Technology Biomass Technology centre Swedish University of Agricultural SciencesUmeaE13Swedn Universidad De La costa Calle 58#55-66080002BarranquillaAtlanticoColombia Research Group on Adsorptive and catalytic Process Engineering(ENGEPAc) Federal University of Santa MariaAv.Roraima100079705900Santa MariaRSBrazil Institute of chemistry Federal University of Rio Grande do Sul90040060Porto AlegreBrazil

chitin powder and chitin-aerogel were prepared from shrimp wastes and used to uptake Y^(3+)from aqueous solutions and concentrate this rare earth element from phosphogypsum(PG).chitin aerogel displays a specific surface area of 945 m^(2)/g,while chitin powder is 3.6 m^(2)/g,which largely influences its adsorption *** the adsorption in synthetic solutions,the effect of pH on Y^(3+)removal is strong for chitin powder *** contrast,no big pH influence was detected for chitin *** interactions and chelation can highlight the proposed mechanism of Y^(3+)on chitin adsorbents for the powder and ***,in addition to these interactions,pore filling/pore diffusion is the main mechanism of Y^(3+)removal in the chitin *** aerogel is efficient in concentrating 8 times the Y^(3+)from PG,a very complex *** complex chitin aerogel-Y^(3+)can be a secondary source of rare earth elements for other applications.

关键词： Rare earths Sustainable material chitin powder chitin porous aerogel Yttrium adsorption and recovery

Pushover analysis of reinforced concrete frames considering shear failure at beam-column joints

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Earthquake Engineering and Engineering Vibration 2013年第3期12卷 373-383页

作者： Y.c.Sung T.K.Lin c.c.Hsiao m.c.Lai Bridge Division Center for Research on Earthquake EngineeringTaipei University of Technology (NTUT) chiao Tung University Taipei University of Technology (NTUT)

Since most current seismic capacity evaluations of reinforced concrete （Rc） frame structures are implemented by either static pushover analysis （PA） or dynamic time history analysis, with diverse settings of the plastic hinges （PHs） on such main structural components as columns, beams and walls, the complex behavior of shear failure at beam-column joints （BcJs） during major earthquakes is commonly neglected. This study proposes new nonlinear PA procedures that consider shear failure at BcJs and seek to assess the actual damage to Rc structures. Based on the specifications of FEmA-356, a simplified joint model composed of two nonlinear cross struts placed diagonally over the location of the plastic hinge is established, allowing a sophisticated PA to be performed. To verify the validity of this method, the analytical results for the capacity curves and the failure mechanism derived from three different full-size Rc frames are compared with the experimental measurements. By considering shear failure at BcJs, the proposed nonlinear analytical procedures can be used to estimate the structural behavior of Rc frames, including seismic capacity and the progressive failure sequence of joints, in a precise and effective manner.

关键词： Rc frame beam-column joint pushover analysis capacity curve plastic hinge performance-based seismic evaluation

Ion acoustic shock and periodic waves through Burgers equation in weakly and highly relativistic plasmas with nonextensivity

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Plasma Science and Technology 2017年第1期19卷 7-19页

作者： m G HAFEZ N c ROY m R TALUKDER m HOSSAIN ALI Department of of Applied mathematics University of Rajshahi Rajshahi-6205 Bangladesh Department of mathematics Chittagong University of Engineering and Technology Chittagong-4349Bangladesh Plasma Science and Technology Lab Department of Applied Physics and Electronic EngineeringUniversity of Rajshahi Rajshahi-6205 Bangladesh

A comparative study is carried out for the nonlinear propagation of ion acoustic shock waves both for the weakly and highly relativistic plasmas consisting of relativistic ions and qdistributed electrons and *** Burgers equation is derived to reveal the physical phenomena using the well known reductive perturbation *** integration of the Burgers equation is performed by the（G￠/G）-expansion *** effects of positron concentration,ion–electron temperature ratio,electron–positron temperature ratio,ion viscosity coefficient,relativistic streaming factor and the strength of the electron and positron nonextensivity on the nonlinear propagation of ion acoustic shock and periodic waves are presented graphically and the relevant physical explanations are provided.

关键词： electron-positron-ion plasmas ion acoustic shock and periodic waves weakly and highly relativistic effects Burgers equation

SURFAcE FINITE ELEmENTS FOR PARABOLIc EQUATIONS

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Journal of computational mathematics 2007年第4期25卷 385-407页

作者： G. Dziuk c.m. Elliott Abteilung für Angewandte mathematik University of Freiburg Hermann-Herder-Straβe 10 D-79104Freiburg i. BrGermany Department of mathematics University of Sussex Falmer Brighton BN1 9RF United Kingdom

In this article we define a surface finite element method （SFEm） for the numerical solution of parabolic partial differential equations on hypersurfaces F in R^n＋1. The key idea is based on the approximation of F by a polyhedral surface Гh consisting of a union of simplices （triangles for n = 2, intervals for n = 1） with vertices on Г. A finite element space of functions is then defined by taking the continuous functions on Гh which are linear affine on each simplex of the polygonal surface. We use surface gradients to define weak forms of elliptic operators and naturally generate weak formulations of elliptic and parabolic equations on Г. Our finite element method is applied to weak forms of the equations. The computation of the mass and element stiffness matrices are simple and straightforward. We give an example of error bounds in the case of semi-discretization in space for a fourth order linear problem. Numerical experiments are described for several linear and nonlinear partial differential equations. In particular the power of the method is demorrstrated by employing it to solve highly nonlinear second and fourth order problems such as surface Allen-cahn and cahn-Hilliard equations and surface level set equations for geodesic mean curvature flow.

关键词： Surface partial differential equations Surface finite element method Geodesic curvature Triangulated surface.

Tagging major quantitative trait loci for sheath blight resistance in a rice variety, Jasmine 85

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chinese Science Bulletin 1999年第19期44卷 1783-1789页

作者： m.c.Rush Louisiana State University Baton RougeLAUSA70803

This study was conducted with a clonal F2 population of rice from a cross between Jasmine 85, a resistant variety, and Lemont, a susceptible cultivar. The rice plants belonging to each F2 clone were divided into two plots, which were put in two replicates, respectively. clonal parents were tested as controls. The plants were inoculated by short toothpicks incubat-

关键词： rice sheath blight major QTLs RFLP.

State of the Art on micromilling of materials,a Review

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Journal of materials Science & Technology 2012年第8期28卷 673-685页

作者： m.A.cmara J.c. campos Rubio A.m. Abro J.P. Davim Department of mechanical Engineering Universidade Federal de Minas GeraisAv.Ant onio Carlos6627-Pampulha Belo Horizonte MGCEP:31.270-901Brazil Department of mechanical Engineering University of AveiroCampus Universitrio de Santiago3810-193AveiroPortugal

The trend towards miniaturization has increased dramatically over the last decade, especially within the fields concerned with bioengineering, microelectronics, and aerospace. micromillin8 is among the principal manu- facturing processes which have allowed the development of components possessing micrometric dimensions, being used to the manufacture of both forming tools and the final product. The aim of this work is to present the principal aspects related to this technology, with emphasis on the work material requirements, tool ma- terials and geometry, cutting forces and temperature, quality of the finished product, process modelling and monitoring and machine tool requirements. It can be noticed that size effect possesses a relevant role with regard to the selection of both work material （grain size） and tooling （edge radius）. Low forces and temper- ature are recorded during micromillin8, however, the specific cutting force may reach high values because of the ploughing effect observed as the uncut chip thickness is reduced. Finally, burr formation is the principal concern with regard to the quality of the finished part.

关键词： micro-milling micromachining Size effect miniaturization

Optimizing the aeration performance of a perforated pooled circular stepped cascade aerator using hybrid ANN-PSO technique

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Information Processing in Agriculture 2022年第4期9卷 533-546页

作者： Subha m.Roy c.m.Pareek Rajendra machavaram c.K.mukherjee Agricultural and Food Engineering Department Indian Institute of Technology KharagpurKharagpur 721302West BengalIndia

Artificial aeration system for aquaculture ponds becomes essential to meet the oxygen requirement posed by the aquatic *** performance of an aerator is generally mea-sured in terms of standard aeration efficiency(SAE),which is significantly affected by the different geometric and dynamic parameters of the ***,to enhance the aer-ation performance of an aerator,these parameters need to be *** the present study,a perforated pooled circular stepped cascade(PPcSc)aerator was developed,and the geometric and dynamic parameters of the developed aerator were optimized using the hybrid ANN-PSO technique for maximizing its aeration *** geometric parameters include consecutive step width ratio(W_(i-1)/W_(i))and the perforation diameter to the bottom-most radius ratio(d/R_(b)),whereas the dynamic parameter includes the water flow rate(Q).A 3–6-1 ANN model coupled with particle swarm optimization(PSO)approach was used to obtain the optimum values of geometric and dynamic parameters correspond-ing to the maximum *** optimal values of the consecutive step width ratio(W_(i-1)/W_(i)),the perforation diameter to the bottom-most radius ratio(d/R_(b)),and the water flow rate(Q)for maximizing the SAE were found to be 1.15,0.0027 and 0.0167 m^(3)/s,*** cross-validation results showed a deviation of 3.07%between the predicted and experimen-tal SAE values,thus confirming the adequacy of the proposed hybrid ANN-PSO technique.

关键词： Aquaculture Artificial neural network(ANN) Particle swarm optimization(PSO) Perforated pooled circular stepped cascade(PPcSc)aerator Standard aeration efficiency(SAE)

Atmospheric pressure gliding arc discharge plasma treatments for improving germination, growth and yield of wheat

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Plasma Science and Technology 2018年第11期20卷 90-100页

作者： N c ROY m m HASAN A H KABIR m A REZA m R TALUKDER A N cHOWDHURY Plasma Science and Technology Laboratory Department of Applied Physics and Electronic EngineeringUniversity of Rajshahi Rajshahi 6205 Bangladesh Department of Agronomy and Agricultural Extension University of Rajshahi Rajshahi 6205 Bangladesh Depatment of Botany University of Rajshahi Rajshahi 6205Bangladesh Department of Genetic Engineering and Biotechnology University of Rajshahi Rajshahi 6205Bangladesh Bangladesh council of Scientific and Industrial Research Laboratory Rajshahi Rajshahi 6206Bangladesh

Wheat （Triticum aestivum） seeds were treated with atmospheric pressure gliding arc discharge plasmas to investigate the effects on water absorption, seed germination rate, seedling growth and yield in wheat. The surface architectures and functionalities of the seeds were found to modify due to plasma treatments. 6 rain treatment was provided 95%-100% germination rate. For the treatment duration of 3 and 9 rain the growth activity, dry matter accumulation, leaves chlorophyll contents, longest spikes, number of spikes/spikelet and total soluble protein content in shoots were improved. The grain yield of wheat was increased ,--20% by 6 min treatment with H2O/O2 plasma with respect to control.

关键词： atmospheric pressure gliding arc discharge plasmas wheat germination growth improvement total soluble protein

Severely deformed copper by equal channel angular pressing

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Progress in Natural Science:materials International 2017年第2期27卷 244-250页

作者： m.Ebrahimi c.Gode Department of mechanical Engineering University of Maragheh School of Denizli Vocational Technology Program of MachinePamukkale University

mechanical and microstructural analysis of equal channel angular pressed copper was experimentally investigated. The results showed that the hardness distribution uniformity was rapidly decreased after the first pass and gradually improved at the following passes. Also, the bottom region of the pressed material experienced lower Vickers hardness magnitude irrespective of pass number. Furthermore, the addition of 0.1%magnesium to the pure copper had a considerable effect on the distribution uniformity. In addition, the material fracture mode changed from ductile to brittle by the alteration of the dimples to cleavage planes ***, the formability index was dramatically reduced after the first pass and slowly improved at the succeeding passes. Eventually, EcAP process led to the increment of low angle grain boundaries and the decrease of high angle grain boundaries at the initial passes and vice versa at the subsequent ones.

关键词： Pure copper Equal channel angular pressing mechanical properties Impact test microstructural observation