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Phase separation and coarsening of NiAl(β′)intermetallic in quench-aged Fe-Ni-Al alloys

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Journal of Iron and Steel Research International 2020年第11期27卷 1331-1338页

作者： C.ferreira-Palma J.A.Rosas-Barrios V.m.Lopez-Hirata D.I.Rivas-Lopez H.J.Dorantes-Rosales Faculty of Chemical Sciences Universidad VeracruzanaVeracruz 94294Mexico ESIQIE Instituto Politecnico Nacional.UPALMMexico City 07738Mexico

The coarsening behavior of four quench-aged Fe-Ni-AI alloys with different Ni and Al con tents is *** alloys were solubilized at 1100℃for 24 h,water-quenched and aged at 850℃for periods ranging from 1 to 100 h to promote phase separation and *** two alloys with the highest combined Ni and Al contents(>35 at.%)showed signs of spinodal decomposition,while the alloys with lower Ni and Al contents followed a classical nucleation *** Ni and Al contents promoted an increase in NiAl(β′)phase fraction in concordance with phase equilibrium *** alloy with the highest[3'fraction presented a completely interconnected *** coarsening ofβ′particles in the other three alloys followed the predictions of the Lifshitz-Slyozov-Wagner(LSW)*** general trend was an increase in the coarsening kinetics with higher Ni and Al *** highest hardness was found in the alloys with higher fraction albeit these compositions are less resistant to coarsening and have been reported to present a low room-temperature ductility.

关键词： Precipitation Spinodal decomposition Coarsening Aging Fe-Ni-Al alloy

Changes in niche differentiation and environmental filtering over a hydric stress gradient

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Journal of Plant Ecology 2020年第2期13卷 185-194页

作者： Alejandra martínez-Blancas carlos martorell Departamento de Ecología y Recursos Naturales Facultad de CienciasUniversidad Nacional Autónoma de MéxicoCoyoacán04510 Ciudad de MéxicoMexico Posgrado en Ciencias Biológicas Universidad Nacional Autónoma de MéxicoAv.Ciudad Universitaria 3000C.P.04510CoyoacánCiudad de MéxicoMexico

Aims Diversity in communities is determined by species’ability to coexist with each other and to overcome environmental stress that may act as an environmental *** differentiation(ND)results in stronger intra-than interspecific competition and promotes *** stress affects interactions,the strength of ND may change along stress gradients.A greater diversity of plant growth forms has been observed in stressful habitats,such as deserts and alpine regions,suggesting greater ND when stress is *** tested the hypothesis that niche differences and environmental filters become stronger with *** In a semiarid grassland in southern mexico,we sowed six annual species in the field along a hydric stress *** were grown alone(without interactions),with conspecific neighbors(intraspecific interactions)or with heterospecific neighbors(interspecific interactions).We analyzed how the ratio of intra-to interspecific competition changed along the gradient to assess how water availability determines the strength of *** also determined if hydric stress represented an environmental *** Findings We observed stronger intra-than interspecific competition,especially where hydric stress was ***,we found ND in at least some portion of the gradient for all but one *** species were hindered by stress,but others were favored by it perhaps because it eliminates soil *** strong ND was slightly more frequent with stress,our species sample was small and there were exceptions to the general pattern,so further research is needed to establish if this is a widespread phenomenon in nature.

关键词： hydrological niche species interactions environmental constraints species coexistence stabilizing mechanisms equalizing mechanisms

Timing of Proterozoic magmatism in the Sunsas belt, Bolivian Precambrian Shield, SW Amazonian Craton

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Geoscience Frontiers 2021年第6期12卷 277-293页

作者： Ingrid m.Nedel Reinhardt A.Fuck Amarildo S.Ruiz Gerardo R.matos-Salinas Alanielson da C.D.ferreira Instituto de Geociências Universidade de Brasília(UnB)Brasília-DFBrazil Faculdade de Geociências Universidade Federal de Mato GrossoCuiabá-MTBrazil Instituto de Investigaciones Geológicas y del medio Ambiente Universidad Mayor de San Andrés(UMSA)Pabellón GeologíaCalle 27Campus Universitario Cota CotaLa PazBolivia Department of Earth Sciences Stellenbosch UniversityPrivate Bag X1Matieland7602 StellenboschSouth Africa

We present new U–Pb zircon and monazite ages from the Sunsas belt granitic magmatism in Bolivia, SW Amazonian Craton. The geochronological results revealed four major magmatic events recorded along the Sunsas belt domains. The older igneous event formed a granitic basement coeval to the Rio Apa Terrane(1.95–1.85 Ga) in the southern domain. The second magmatic episode is represented by 1.68 Ga granites associated to the Paraguá Terrane(1.69–1.66 Ga) in the northern domain. The 1.37–1.34 Ga granites related to San Ignacio orogeny represent the third and more pervasive magmatic event, recorded throughout the Sunsas belt. moreover, magmatic ages of ~1.42 Ga revealed that the granitogenesis associated to the Santa Helena orogeny also affected the Sunsas belt, indicating that it was not restricted to the Jauru Terrane. Lastly, the 1.10–1.04 Ga youngest magmatism was developed during the Sunsas orogeny and represents the final magmatic evolution related to Rodinia assembly. Likewise, the 1.95–1.85 and 1.68 Ga inherited zircon cores obtained in the ~1.3 Ga and 1.0 Ga granite samples suggest strong partial melting of the Paleoproterozoic sources. The 1079 ± 14 ma and 1018 ± 6 ma monazite crystallization ages can be correlated to the collisional tectono-thermal event of the Sunsas orogeny, associated to reactions of medium-to high-grade metamorphism. Thus, the Sunsas belt was built by heterogeneous 1.95–1.85 Ga and 1.68 Ga crustal fragments that were reworked at 1.37–1.34 Ga and 1.10–1.04 Ga related to orogenic collages. Furthermore, the 1.01 Ga monazite age suggests that granites previously dated by zircon can bear evidence of a younger thermal history. Therefore, the geochronological evolution of the Sunsas belt may have been more complex than previously thought.

关键词： SW Amazonian Craton Sunsas belt U–Pb geochronology Zircon monazite

Production of Ca<sub>2</sub>AlNbO<sub>6</sub>Ceramics and Study of Their Stability in Crude Petroleum for the Conservation of metallic Sensing Elements used in Petroleum Extraction

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materials Sciences and Applications 2012年第6期3卷 408-413页

作者： Yogendra P. Yadava marilaine m. de Lima José carlos S. Oliveira Ricardo A. Sanguinetti ferreira Departamento de Engenharia mecanica Universidade Federal de Pernambuco Recife Brasil

In the present work a niobium based complex cubic perovskite oxide Ca2AlNbO6 ceramic was produced, characterized and studied its stability in crude petroleum environment for inert ceramic embedding for temperature sensors used in petroleum extraction. Ca2AlNbO6 ceramic powder was prepared through thermo-mechanical processing. Structural characteristics of calcined material was investigated by powder X-ray diffarctometry, which presented a single phase complex cubic perovskite structure with lattice parameter a = 7.6599 ?. Compacted discs of Ca2AlNbO6 ceramics were sintered in the temperature range 1250°C - 1350°C during 24 hours in ambient atmosphere. microstructure of the sintered ceramics was studied by scanning electron microscopy and mechanical behavior was studied by Vicker’s microhardness testing. Ca2AlNbO6 ceramics sintered at 1350°C presented best results in terms of microstructural homogeneity and mechanical hardness. Therefore these sintered ceramics were submerged in crude petroleum for 60 days. Ceramics were taken out from the petroleum periodically and subjected to structural, microstructural and mechanical characterizations. Results showed that ceramics submerged in crude petroleum did not suffer any change at any stage of submersion. These characteristics make this material suitable for inert ceramic embedding for sensors used in petroleum extraction.

关键词： Ca2AlNbO6 Production microstructure mechanical Properties Stability in Crude Petroleum

mAGNETIC STRIPS TO SImULATE LAYERED BRITTLE SOLIDS IN CLEAVAGE AND FRACTURE EXPERImENTS

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Acta mechanica Solida Sinica 2008年第4期21卷 333-336页

作者： Francisco G.Emmerich Alfredo G.Cunha carlos m.A.Girelli Arnobio I.Vassem Laboratory of Carbon and Ceramic materials Department of PhysicsUniversidade Federal do Espirito Santo29075-910 Vitoria-ESBrazil

A characteristic of the fracture and cleavage experiments is that they are usually intrinsically destructive. Cracks do not completely heal in an unstressed system, even in crystals such as mica. Here, we used magnetic solids composed of magnetic strips for the non-destructive cleavage and brittle fracture experiments. Between the magnetic strips materials with different mechanical characteristics can be inserted, such as Teflon or foam strips, to change the mechanical properties of the solid. For the cleavage experiments, we developed an apparatus where parameters such as the main involved force can be measured easily. By inserting flaws, the magnetic solid can be used in dynamic fracture experiments, with the advantages of simulating macroscopically a non-destructive experiment in an easier way, that happen in real materials with much higher velocities. The apparatus and the used magnetic solid may be useful for demonstrations of fractures in classes.

关键词： layered brittle solids non-destructive measurements cleavage fracture

Contribution of inrush current to mechanical failure of power transformers windings

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High Voltage 2019年第4期4卷 300-307页

作者： Rafael m.R.Barros Edson Gda Costa Jalberth F.Araujo Filipe L.mde Andrade Tarso V.ferreira Department of Electrical Engineering Federal University of Campina GrandeAprigio Veloso St.882Campina GrandeBrazil

This work presents a study regarding the contribution of inrush current to the occurrence of mechanical fatigue in windings of a power transformer and,consequently,the impact of that phenomenon on the equipment's *** order to perform the study,electromagnetic transient simulations were used to determine the inrush current in a three-phase transformer ***,three-dimensional simulations,based on the finite element method,were performed to determine the electromechanical stresses in the equipment windings,under the effect of the inrush ***,the methods of critical plans and Palmgren–miner were applied to perform the fatigue *** the results,the impact of inrush current on the integrity of the transformer's windings was determined,as well as,to estimate the reduction of lifespan of the equipment due to inrush *** number of inrushes needed for the total reduction of lifespan of the equipment due to mechanical fatigue was also *** results can be used in the transformers design stage,with the purpose of assisting the evaluation of mechanical withstand of equipment,which can minimise the possibility of failure and increase its lifespan.

关键词： winding fatigue power

Inositol 1,4,5-trisphosphate receptor in the liver:Expression and function

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World Journal of Gastroenterology 2019年第44期25卷 6483-6494页

作者： Fernanda de Oliveira Lemos Rodrigo m Florentino Antonio carlos melo Lima Filho marcone Loiola dos Santos m Fatima Leite Department of Physiology and Biophysics Universidade Federal de Minas GeraisBelo HorizonteMinas Gerais 31270-901Brazil Department of Cell Biology Universidade Federal de Minas GeraisBelo HorizonteMinas Gerais 31270-901Brazil

The liver is a complex organ that performs several functions to maintain *** functions are modulated by calcium,a second messenger that regulates several intracellular *** hepatocytes and cholangiocytes,which are the epithelial cell types in the liver,inositol 1,4,5-trisphosphate(InsP3)receptors(ITPR)are the only intracellular calcium release *** isoforms of the ITPR have been described,named type 1,type 2 and type *** ITPR isoforms are differentially expressed in liver cells where they regulate distinct physiological *** in the expression level of these receptors correlate with several liver diseases and hepatic *** this review,we highlight how the expression level,modulation,and localization of ITPR isoforms in hepatocytes and cholangiocytes play a role in hepatic homeostasis and liver pathology.

关键词： Inositol 1,4,5-trisphosphate receptor Liver Calcium signaling Hepatocytes and cholangiocytes

Neutrophils are shaped by the tumor microenvironment:novel possibilities for targeting neutrophils in cancer

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Signal Transduction and Targeted Therapy 2024年第5期9卷 1788-1790页

作者： carlos Silvestre-Roig Lydia Kalafati Triantafyllos Chavakis Institute of Experimental Pathology(ExPat) Center for Molecular Biology of Inflammation(ZMBE)University of MünsterMünsterGermany Institute for Clinical Chemistry and Laboratory medicine University Hospital and Faculty of MedicineTechnische Universität DresdenDresdenGermany

In a recent paper published in Science,Ng et *** seminal insights into the process through which neutrophils are reprogrammed by the tumor environment,leading to a convergent transition from different neutrophil states towards a unique end-stage differentiated pro-tumor phenotype.1 These findings have major translational implications as they provide potential neutrophil-related targets for tumor immunotherapy.

关键词： al. neutrophils tumor

Separation,speciation and quantification of both chromium(Ⅵ)and chromium(Ⅲ)in tanned leather samples:a comparative study and validation of analytical methods

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Collagen and Leather 2023年第2期5卷 51-66页

作者： mónica Gisel Arellano-Sánchez Juliette Vievard Lamia moufarrej Christine Devouge-Boyer marie Hubert-Roux carlos Afonso mélanie mignot COBRA UmR CNRS 6014 INSANormandie UniversityUNIROUENAvenue de l'Université76800 Saint-Etienne-du-RouvrayFrance COBRA UMR CNRS 6014IRCOFNormandie UniversityUNIROUEN76821 Mont-Saint-Aignan CedexFrance

In the present work,a comparative study of analytical methods for the simultaneous and quantitative determination of trivalent and hexavalent chromium is *** the analysis by ion chromatography-inductively coupled plasma-mass spectrometry,two different columns were tested,as well as different mobile phases and different pH of the *** optimized analytical method permitted the separation of Cr(Ⅲ)and Cr(Ⅵ)using 75 mmol/L NH_(4)NO_(3)pH 3 as chromatographic *** method was validated and applied to real samples,allowing the determination of both species simultaneously,even when there is a huge difference of concentration between Cr(Ⅲ)and Cr(Ⅵ).Limit of detection and limit of quantification for Cr(Ⅲ)were found to be 0.016 and 0.054μg/L(0.3 and 1.1μg/kg),respectively,and for Cr(Ⅵ)0.13 and 0.43μg/L(7 and 22μg/kg),*** species interconversions were monitored through the use of chromium isotopic standards,which confirmed that the optimized methodology preserves chromium speciation during extraction and ***-transform ion cyclotron resonance-mass spectrometry permitted the structure elucidation of the complex formed during ethylenediaminetetraacetic acid extraction.

关键词： Chromium speciation Tanned leather Interconversions Ion chromatography Inductively coupled plasmamass spectrometry Fourier-transform ion cyclotron resonance mass spectrometry