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International Journal of Minerals,Metallurgy and Materials 2016年第4期23卷 458-465页

作者： Rocio Ochoa Alfredo Flores Jesus Torres cinvestav-saltillo

The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values： 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450？500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.

关键词： aluminothermic reduction alkaline batteries zinc oxide waste utilization aluminum zinc magnesium alloys

EBSD Investigation on Effect of Cooling Rate on Microstructure and Transformation Textures of High Strength Hot-rolled Steel Plates

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Journal of Iron and Steel Research International 2016年第3期23卷 261-269页

作者： Nancy M.LOPEZ GRANADOS Armando SALINAS RODRIGUEZ Department of Metallurgical Engineering and Materials Science Center of Research and Advanced StudiesCINVESTAV-Unidad Saltillo

The effect of cooling rate on the microstructure and transformation textures of high strength hot-rolled steels was *** treated samples subjected to different cooling conditions were characterized by optical and scanning electron microscopes using orientation imaging microscopy（OIM）.The experimental results demonstrate that there is a significant effect of cooling rate on microstructures and textures resulting from phase *** cooling rates lead to the appearance of the cube（001）[010],rotated cube（001）[110]/（001）[110],Goss（110）[001]and rotated Goss（110）[110]*** contrast,textures developed at rapid cooling rates are preferably of Cu（112）[111],Br（110）[112],transformed Cu（113）[110]and transformed Br（332）[113]/（112）[131].These texture changes are attributed to the selective character of the phase *** OIM technique was used to have a better understanding of the formation of phases and their relationship between microstructure and processing *** volume fraction of micro-constituents resulting from phase transformation such as bainite,martensite and different types of ferrite,can be measured satisfactorily by this technique correlating image quality of EBSD patterns to specific phases.

关键词： orientation imaging microscopy texture phase transformation microstructure steel

Thermodynamic and experimental studies on removal of calcium and sulfate ions from recycling water of complex sulfide flotation operations

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Transactions of Nonferrous Metals Society of China 2021年第10期31卷 3116-3127页

作者： Elvis BUSTOS-FLORES Martha Araceli ELIZONDO-ÁLVAREZ Alejandro URIBE-SALAS Department of Metallurgical Engineering CINVESTAV-IPNUnidad Saltillo25900Ramos ArizpeCoahuilaMexico

A chemical method for removing calcium sulfate saturated solutions(0.016 mol/L CaSO_(4))using barium chloride(BaCl_(2)∙2H_(2)O)and sodium phosphate(Na_(3)PO_(4))was experimentally *** main interest is to remove these ions from the solution through the precipitation of two solid species:sulfate(SO_(4)^(2−))as barite(BaSO4),and calcium(Ca^(2+))as hydroxyapatite(Ca_(5)(PO_(4))_(3)OH).Additionally,a solid/liquid separation method(i.e.,flotation)was explored,using oleic acid and dodecylamine as *** results show that,the chemical treatment of saturated solutions at 60℃,pH 11.5 and using 3.9 g/L BaCl_(2)·2H_(2)O and 1.6 g/L Na_(3)PO_(4),promotes the precipitation of barium sulfate and calcium-deficient hydroxyapatite(Ca_(10−x)(HPO_(4))_(x)(PO_(4))_(6−x)(OH)_(2−x)),with residual concentrations of calcium and sulfate below 0.10 and 5 mg/L,*** residual calcium concentration increases to 28 mg/L when using the same amount of reactants,at temperature and pH values below those *** highest flotation recovery of hydroxyapatite with oleic acid at pH 9.5 was about 80%,while that of barite floated with dodecylamine at pH 6.5 was about 90%.

关键词： calcium sulfate dodecylamine oleic acid barite hydroxyapatite flotation separation

Cerium extraction by metallothermic reduction using cerium oxide powder injection

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Journal of Rare Earths 2011年第1期29卷 74-76页

作者： J.S.Luna A A.Flores V R.Muiz V A.F.Fuentes J.Torres N.Rodríguez R J.C.Ortiz P.Orozco cinvestav unidad saltillo Saltillo-Monterrey Highway Km.13.5P.O.Box 66325000SaltilloCoahuilaMéxico Faculty of Engineering Autonomous Univer-sity of CoahuilaCamporedondo UnitSaltilloCoahuilaMéxico Department of Metal Mechanics Technological Institute of SaltilloV.Carranza Blvd 2400SaltilloCoahuilaZC 25280México Academic Unit of Engineering Autonomous University of CoahuilaLopez Velarde Av.ZacatecasZac.ZC 98060

This work presented the feasibility of cerium recovery by Al-Mg alloy through the metallothermic reduction of CeO2 to obtain a master alloy Al-4%Ce. The master alloy obtained in this investigation was for the grain refinement and modification of Al-Si alloys. The reagent was incorporated into a molten alloy using the submerged powder injection technique, and metallic samples were obtained during injection. Chemical and microstructural analyses （by inductively coupled plasma （ICP） and scanning electron microscopy （SEM）, respectively） confirmed the possibility of Ce uptake in the bath （0 to 4 wt.%）, as CeO2 was reduced through metallothermic reactions in the molten alloys. Based on the characterization of reaction products, the sequence of the reaction was proposed.

关键词： cerium recovery metallothermic reduction reaction products rare earths

Characterization by EBSD of Antimony-calcium Rich Phases Formed during Purification of Aluminum Scrap

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Journal of Wuhan University of Technology(Materials Science) 2013年第4期28卷 647-649页

作者： MUIZ Rodrigo FLORES Alfredo ORTIZ Juan RODRíGUEZ Nelly MARTíNEZ Fernando LUNA Jesús OROZCO Pilar Faculty of Engineering Autonomous University of Coahuila Camporedondo Unit cinvestav saltillo Unit Department of Metal Mechanics Technological Institute of Saltillo Faculty of Engineering Autonomous University of Zacatecas

We studied the influence of antimony on the modification rate of the silicon eutectic with sodium and/or strontium for castiig of A1-Si alloys, and introduced controlled Ca and Sb to the system and studied the resulting compounds, which were determined to be CazSb and A1Sb. Scanning electron microscopy together with the complementary technique of electron backscatter diffraction （EBSD） were used to characterize the materials. The experimental results provided the basis for us to establish that antimony removal from AI occurs mainly through the reaction （Sb）A1 ＋ 2Ca = Ca^Sb ＋ A1.

关键词： aluminum alloys antimony contamination modification

Microstructural Feature of As-cast A-356 Alloy Modifiers with the Addition of SrO

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Journal of Wuhan University of Technology(Materials Science) 2014年第3期29卷 617-619页

作者： MU?IZ Rodrigo FLORES Alfredo ORTIZ Juan RODRíGUEZ Nelly MARTíNEZ Fernando OROZCO Pilar LUNA Jesús Equihua Fabián García Adrián Faculty of Engineering Autonomous University of Coahuila Camporedondo UnitSaltillo Coahuila México cinvestav saltillo Unit Department of Metal Mechanics Technological Institute of Saltillo Faculty of Engineering Autonomous University of Zacatecas FIME Autonomous University of Coahuila Unit

To explore the effect of strontium on the structure of as-cast A356 alloy, the strontium was incorporated to the alloy by metallothermic reduction of SrO where the mineral was added to the melt through the submerged powders injection technique. The evaluation of the modification of the eutectie silicon and the chemical analysis of samples were done using optical microscopy （OP） and inductively coupled plasma （ICP）, respectively, while microstructural analyses by scanning electron microscopy （SEM）, and the injection time was variable. Magnesium was added to the melt to increase the reactivity and reduce the surface tension of the molten aluminum. It was possible to increase the strontium content from 0 to 0.027% after 20 minutes treatment. This concentration was sufficient to bring about full modification structure of eutectic silicon of as cast alloy A 356 and the acceptable quality metallurgical of alloy.

关键词： modification microstmcture strontium eutectic silicon submerged powder injection

A Numerical Study Comparing the Effect on Residual Stresses of Two Different Types of Projectiles During Shot Peening

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Computers, Materials & Continua 2016年第3期51卷 203-215页

作者： J.Solórzano-López F.A.García-Pastor Angélica Flores-Luna UNAM Facultad de QuímicaCiudad de MéxicoMéxico cinvestav unidad saltillo CoahuilaMéxico TecNM Instituto Tecnológico de Tláhuac IIICiudad de MéxicoMéxico

Shot peening is a widely used technique to improve fatigue life in metallic *** processing technique introduces a subsurface compressive residual stress field through a plastic deformation of the surface caused by the impact of a large number of high-speed *** are a number of parameters that affect the residual stress field depth and *** effects of the impact angle,shot speed and shot geometry are currently being *** particular,substituting spherical cast shots by cylindrical cut wire shots is an attractive option,especially in terms of *** effect of shot geometry on residual stresses,however,needs to be further *** industrial-scale experimentation is costly and cumbersome,mathematical modeling offers a convenient alternative to carry out this type of *** present work shows a comparison between the residual stresses generated by the impact of spherical and cylindrical projectiles on a steel *** threedimensional model was developed using ABAQUS finite element commercial software(Release 6.12,Dassault Systémes,France).The results show that cylindrical shots generate residual stress fields t hat a re higher in magnitude than t hose generated by a spherical ***,the residual stress field of cylindrical shots impacting the surface at an oblique angle shows an important degree of *** effect is not found when spherical shots impact the surface at the same oblique angle.

关键词： Shot Peening Finite element method Residual Stresses

Greenhouse Gas Emissions and Growth of Wheat Cultivated in Soil Amended with Digestate from Biogas Production

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Pedosphere 2017年第2期27卷 318-327页

作者： Liliana PAMPILLON-GONZALEZ Marco LUNA-GUIDO Victor Manuel RUIZ-VALDIVIEZO Olivia FRANCO-HERNANDEZ Fabign FERNANDEZ-LUQUENO Oetavio PAREDES-LOPEZ Gerardo HERNANDEZ Luc DENDOOVEN PhD Program on Science Technology and Society Cinvestav IPN 2508 Mexico DF 07360 (Mexico) Laboratory of Soil Ecology Laboratorio de Matemdticas Aplicadas y Cdmputo de Alto Rendimiento Cinvestav-Edomex (ABACUS) Cinvestav IPN 2508 Mexico DF 07360 (Mexico) Department of Chemistry Unidad Profesional Interdisciplinaria de Biotecnologla-Instituto Politdcnico Nacional (UPIBI-IPN) Me- xico DF 07340 (Mexico) Sustainability of Natural Resources and Energy Program Cinvestav-Saltillo 1062 Coahuila 25900 (Mexico) Department of Biotechnology and Biochemistry Cinvestav Irapuato 36821 (Mexico)

Digestate, the product obtained after anaerobic digestion of organic waste for biogas production, is rich in plant nutrients and might be used to fertilize crops. Wheat （Triticum spp. L.） was fertilized with digestate, urea, or left unfertilized and cultivated in the greenhouse for 120 d. Emissions of greenhouse gasses （carbon dioxide （CO2）, methane （CH4）, and nitrous oxide （N20）） were monitored and plant growth characteristics were determined at harvest. The digestate was characterized for heavy metals, pathogens, and C and N mineralization potential in an aerobic incubation experiment. No Salmonella spp., Shigella spp., or viable eggs of helminths were detected in the digested pig slurry, but the number of faecal coliforms was as high as 3.6 ~ 104 colony-forming units （CFU） g-1 dry digestate. The concentrations of heavy metals did not surpass the upper limits established by US Environmental Protection Agency （EPA）. After 28 d, 17% of the organic C （436 g kg-1 dry digestate） and 8% of the organic N （6.92 g kg-1 dry digestate） were mineralized. Emissions of CO2 and CH4 were not significantly affected by fertilization in the wheat-cultivated soil, but digestate significantly increased the cumulative N20 emission by 5 times compared to the urea-amended soil and 63 times compared to the uncultivated unfertilized soil. It could be concluded that digestate was nutrient rich and low in heavy metals and pathogens, and did not affect emissions of CH4 and CO2 when applied to a soil cultivated with wheat, but increased emission of N20. Key Words： biodigester, C and N mineralization potential, faecal coliform, heavy metal, pathogen, pig slurry

关键词： biodigester C and N mineralization potential faecal coliform heavy metal pathogen pig slurry

Plant Proteins Are Smaller Because They Are Encoded by Fewer Exons than Animal Proteins

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Genomics, Proteomics & Bioinformatics 2016年第6期14卷 357-370页

作者： Obed Ramirez-Sachez Paulino Perez-Rodriguez Luis Delaye Axel Tiessen Genetic Engineering Department CINVESTAV Unidad IrapuatoIrapuatoCP 36821Mexico Colegio de Postgraduados Campus MontecilloTexcocoCP 56230Mexico

Protein size is an important biochemical feature since longer proteins can harbor more domains and therefore can display more biological functionalities than shorter proteins. We found remarkable differences in protein length, exon structure, and domain count among different phylo- genetic lineages. While eukaryotic proteins have an average size of 472 amino acid residues （aa）, average protein sizes in plant genomes are smaller than those of animals and fungi. Proteins unique to plants are -81 aa shorter than plant proteins conserved among other eukaryotic lineages. The smaller average size of plant proteins could neither be explained by endosymbiosis nor subcellular compartmentation nor exon size, but rather due to exon number. Metazoan proteins are encoded on average by -10 exons of small size [-176 nucleotides （nt）]. Streptophyta have on average only -5.7 exons of medium size （-230 nt）. Multicellular species code for large proteins by increasing the exon number, while most unicellular organisms employ rather larger exons （〉 400 nt）. Among subcellular compartments, membrane proteins are the largest （-520 aa）, whereas the smallest proteins correspond to the gene ontology group of ribosome （-240 aa）. Plant genes are encoded by half the number of exons and also contain fewer domains than animal proteins on average. Interestingly, endosymbiotic proteins that migrated to the plant nucleus became larger than their cyanobacterial orthologs. We thus conclude that plants have proteins larger than bacteria but smaller than animals or fungi. Compared to the average of eukaryotic species, plants have -34% more but -20% smaller proteins. This suggests that photosynthetic organisms are unique and deserve therefore special attention with regard to the evolutionary forces acting on their genomes and proteomes.

关键词： Digital proteome Eukarya Evolution Viridiplantae Polypeptide length

Surface Properties of Fe_4N Compounds Layer on AISI 4340 Steel Modified by Pulsed Plasma Nitriding

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Journal of Materials Science & Technology 2013年第3期29卷 287-290页

作者： J.C.Díaz-Guillén G.Vargas-Gutiérrez E.E.Granda-Gutiérrez J.S.Zamarripa-Pia S.I.Pérez-Aguilar J.Candelas-Ramírez L.lvarez-Contreras Centro de Investigacin en Materiales Avanzados S.C.Miguel de Cervantes 120Complejo Industrial ChihuahuaC.P.31109 ChihuahuaChihuahuaMexico Corporacin Mexicana de Investigacin en Materiales S.A.de C.V.Ciencia y Tecnología No 790Fracc.Saltillo 400C.P.25290 SaltilloCoahuilaMexico Centro de Investigacin y Estudios Avanzados del IPN Unidad SaltilloCarretera Saltillo Monterrey km 13Apdo.Postal 663C.P.25000 SaltilloCoahuilaMexico

In this work, the effect of nitriding current density on hardness, crystalline phase composition, layer thickness and corrosion rate of AlSl 4340 steel has been studied. X-ray diffraction analysis shows that thin layers formed during nitriding process are constituted of 7-Fe4N for samples processed between 1 and 2.5 mA/cm2. Thickness of nitrided layer increases proportionally to current density （0 μm for 0.5 mA/cm2 to 15 pm for 2.5 mA/cm2）. Plasma nitriding increased the surface hardness from 300 HV50g for untreated sample, to around 800HV5og for nitrided samples at 1 mA/cm2. While the untreated samples exhibited a corrosion rate of 0.153 mm per year, the corrosion performance was improved up to 0.03 mm per year at current densities above 1 mA/cm2, which is about one fifth of the corrosion rate of the untreated sample.

关键词： Plasma nitriding Current density Hardness Corrosion