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Effect of rhenium on the microstructure and mechanical behavior of Fe–2.25Cr–1.6W–0.25V-0.1C bainitic steels

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journal of Materials Science & Technology 2017年第12期33卷 1487-1493页

作者： josé antonio jiménez Manuel Carsí Oscar antonio Ruano Department of Physical Metallurgy Centro Nacional de lnvestigaciones MetalurgicasC.S.I.CAvda.Gregorio del Amo 828040 MadridSpain

A new ferritic creep resistant steel has been developed by eliminating Nb and adding 1.5 mass % Re to a ferritic steel grade T/P23 with the aim of enhancing its mechanical properties at high *** ingots of both steels, new grade and ASTM T/P 23, were hot rolled at 900℃ and then submitted to a thermal treatment consisting of solubilization at 1050℃ and tempering at 700℃. Tempered bainitic microstructures obtained contain second phases reinforcing carbide particles, mainly M_6C and M_（23）C_6 at the boundaries of both, prior austenite grains and bainitic ferrite laths, as well as MC within the grains. Mechanical properties at temperatures ranging from 540 to 600℃ were studied by strain-ratechange tests in compression at strain rates between 10^（-7） and 10^（-4）s^（-1）. These tests showed high stress exponents（n ≥ 20） and activation energies（Q ≈ 400 k j/mol） for both alloys, which were associated with a dislocation movement mechanism with a strong interaction between dislocations and precipitates. On the other hand, a creep exponent of 5 was derived for the stress dependence of minimum creep rate from conventional-type creep tests at 600℃. Although this stress exponent is usually related to a dislocation climb controlled creep mechanism, remarkable microstructural degradation observed with increasing creep time makes difficult to elucidate the true deformation mechanism controlling creep.

关键词： Creep resistant steel T/P23 Thermal treatment Tempered bainite High temperature mechanical properties Creep

The assessment of climatic,environmental,and socioeconomic aspects of the Brazilian Cerrado

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Ecological Processes 2023年第1期12卷 274-285页

作者： Washington Luiz Félix Correia Filho joséFrancisco de Oliveira-júnior Dimas de Barros Santiago Hazem Ghassan Abdo Hussein Almohamad Ahmed Abdullah Al Dughairi Carlos antonio da Silva junior Postgraduate Program in Environmentrics(PPGAmb) Institute of MathematicsStatisticsand Physics(IMEF)Federal University of Rio Grande(FURG)Rio GrandeRio Grande do Sul 96203-900Brazil Institute of Atmospheric Sciences(ICAT) Federal University of Alagoas(UFAL)MaceióAlagoas 57072-260Brazil Postgraduate Program in Biosystems Engineering(PGEB) Federal Fluminense University(UFF)NiteróiRio de Janeiro 24220-900Brazil Postgraduate Program in Meteorology Unidade Acadêmica de Ciências Atmosféricas(UACA)Federal University of Campina Grande(UFCG)Campina GrandeParaíba 58429-140Brazil Geography Department Faculty of Arts and HumanitiesTartous UniversityTartousSyria Geography Department Faculty of Arts and HumanitiesDamascus UniversityDamascusSyria Geography Department Faculty of Arts and HumanitiesTishreen UniversityLat-takiaSyria Department of Geography College of Arabic Language and Social StudiesQassim UniversityBuraydah 51452Saudi Arabia Departamento de Geografia State University of Mato Grosso(UNEMAT)SinopMato Grosso 78555-000Brazil

Background The Cerrado is the most biodiverse savanna and maintains other *** of its significance,this paper evaluated the Brazilian Cerrado’s climatic,environmental,and socioeconomic aspects using remote sensing data and spatial statistics(correlation analysis and principal components analysis—PCA).Following the measures of sample adequacy(MSA)and Kaiser–Meyer–Olkin(KMO)tests,seventeen variables were *** The MSA revealed that the dataset had a good quality(0.76),and nine variables were selected:elevation,evapotranspiration,active fires,Human Development Index(HDI),land use and land cover(LULC;shrubland and cropland/rainfed),rainfall(spring and autumn),and *** correlation matrix indicated a positive(negative)association between HDI and autumn rainfall(HDI and active fires)with a value of 0.77(-0.55).The PCA results determined which three principal components(PC)were adequate for extracting spatial patterns,accounting for 68.02%of the total variance with respective values of 38.59%,16.89%,and 12.5%.Due to economic development and agribusiness,Cerrado’s northern(central,western,and southern)areas had negative(positive)score HDI values,as shown in ***(rainfall—spring and fall)and environmental(cropland/rainfed and shrubland)aspects dominated the PC2,with negative scores in northern and western portions due to the transition zone between Amazon and Cerrado biomes caused by rainfall *** the other hand,environmental aspects(LULC-shrubland and elevation)influenced the PC3;areas with high altitudes(>500 m)received a higher *** Agricultural expansion substantially affected LULC,leading to deforestation-caused suppression of native vegetation.

关键词： Environment Agribusiness Active fire Human Development Index Land use and land cover

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A Proof of Wedderburn＇s Theorem

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Algebra Colloquium 2015年第4期22卷 603-606页

作者： josé antonio Cuenca Mira Departamento de álgebra Geometría y Topología Facultad de Ciencias Universidad de Málaga 29071 Málaga Spain

In this note we first introduce the finite weak Herstein condition, which is a property that holds for every finite field. For a field F satisfying the finite weak Herstein condition, we then characterize whether all the finite-dimensional division F-algebras are commutative. This gives an alternate proof of Wedderburn＇s Theorem.

关键词： division algebra finite-dimensional algebra finite field Galois extension

Gravitational waves from compact objects

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Research in Astronomy and Astrophysics 2010年第11期10卷 1071-1099页

作者： josé antonio de Freitas Pacheco University of Nice-Sophia Antipolis Observatoire de la Cote d'Azur Laboratoire Cassiopée-UMR 6202 BP 4229-F606304-Nice Cedex 4-France

Large ground-based laser beam interferometers are presently in operation both in the USA （LIGO） and in Europe （VIRGO） and potential sources that might be detected by these instruments are revisited. The present generation of detectors does not have a sensitivity high enough to probe a significant volume of the universe and, consequently, predicted event rates are very low. The planned advanced generation of interferometers will probably be able to detect, for the first time, a gravitational sig- nal. Advanced LIGO and EGO instruments are expected to detect few （some）： binary coalescences consisting of either two neutron stars, two black holes or a neutron star and a black hole. In space, the sensitivity of the planned LISA spacecraft constellation will allow the detection of the gravitational signals, even within a ＂pessimistic＂ range of possible signals, produced during the capture of compact objects by supermassive black holes, at a rate of a few tens per year.

关键词： gravitational waves -- neutron stars -- black holes

The Threshold Percolation Volume Fraction of Vitreous Silica on the Thermal Expansion Behavior of Quartz

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journal of Materials Science and Chemical Engineering 2019年第6期7卷 1-6页

作者： josé antonio Alves júnior joao Baptista Baldo The Federal University of Sao Carlos(UFSCar) Materials Engineering Department(DEMa)Sao CarlosSPBrazil

In this work, it is shown how the additions of vitreous silica of particle size ?C.

关键词： Quartz Vitreous Silica Thermal Expansion Behavior Percolation Threshold

The Effect of Nano-Alumina Particles Generated in Situ in the Matrix of Ultralow and No Cement 85 wt%Al_(2)O_(3) Refractory Castables

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journal of Materials Science and Chemical Engineering 2019年第6期7卷 7-22页

作者： josé antonio Alves júnior joao Baptista Baldo Department of Materials Engineering Federal University of Sao Carlos via Washington LuisSao CarlosSPBrazil

Advanced high alumina refractory castables of ultra-low and to cement types, are well-known because of their ability on developing similar and/or superior thermal and mechanical properties. Following the recent trend of including nanoparticles in refractory castables, in this work, it is presented a novel way to obtain the benefit effects on the thermal and mechanical properties, promoted by the development in situ, of alumina’s nanoparticles in the matrix of castable (85 wt% Al2O3). The alumina nanoparticles were originated in situ after firing, due to the pyrolysis and oxidation of an aqueous resin, produced by the Pechini process. The resin played a double role, one as mixing liquid vehicle and the other as the aluminum oxide nanoparticles precursor. The results indicate a strong increase in flexural strength and elastic modulus as well as leading to a higher residual strength after thermal shock.

关键词： Low Cement Refractory Castable Alumina Nanoparticles Elastic Modulus Impulse Excitation Technique

Evaluation of the effectiveness of horizontal subsurface flow constructed wetlands for different media

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journal of Environmental Sciences 2010年第6期22卷 820-825页

作者： antonio Albuquerque josé Oliveira Sabrina Semitela Leonor Amaral Department of Civil Engineering and Architecture and C-MADE University of Beira Interior Municipality of Penamacor Department of Sciences and Environmental Engineering Faculty of Sciences and TechnologyNew University of Lisbon

Two media bed （gravel and Filtralite NR） were tested in a mesocosm to evaluate the removal of organic matter （as chemical oxygen demand （COD））, ammonia （NH4-N）, nitrite, nitrate and solid matter （as total suspended solids （TSS）） for a synthetic wastewater （acetate-based） and a domestic wastewater. The use of Filtralite allowed average removal rates （6--16.8 g COD/（m^2·day）, 0.8-1.1 g NH4-N/（m^2·day） and 3.1 g TSS/（m^2·day）） and removal efficiencies （65%-93%, 57%-85% and 78% for COD, NH4-N and TSS, respectively）, higher than that observed in the experiments with gravel. The applied loads of COD, ammonia, nitrate and TSS seem to influence the respective removal rates but only for the treatment of domestic wastewater with nigher correlation coefficients for Filtralite. Regardless the type of media bed and the type of wastewater, nitrate was completely removed for nitrogen loading rates up to 1.3 g NO3-N/（m^2·day）. There was no evidence of the influence of nitrate loads on the removal of organic matter.

关键词： media bed constructed wetlands pollutants removal rates

Object-based image analysis supported by data mining to discriminate large areas of soybean

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International journal of Digital Earth 2019年第3期12卷 270-292页

作者： Carlos antonio da Silva junior Marcos Rafael Nanni josé Francisco de Oliveira-júnior Everson Cezar Paulo Eduardo Teodoro Rafael Coll Delgado Luciano Shozo Shiratsuchi Muhammad Shakir Marcelo Luiz Chicati Geotechnology Applied in Agriculture and Forest(GAAF) State University of Mato Grosso(UNEMAT)Alta FlorestaMato GrossoBrazil Department of Agronomy(DAG/PGA) State University of Maringá(UEM)MaringáParanáBrazil Institute of Atmospheric Sciences(ICAT) Federal University of Alagoas(UFAL)MaceióAlagoasBrazil Federal University of Mato Grosso do Sul(UFMS) Chapadão do SulMato Grosso do SulBrazil Department of Environmental Sciences(DCA) Forestry Institute(IF)Federal Rural University of Rio de Janeiro(UFRRJ)SeropédicaRio de JaneiroBrazil AgCenter Louisiana State University(LSU)Baton RougeLAUSA Institute of Space Technology Islamabad Pakistan IslamabadPakistan

This research aimed to analyze the possibility to estimate and automatically map large areas of soybean cultivation through the use of MODIS(Moderate-Resolution Imaging Spectroradiometer)*** major techniques were used:GEOgraphic-Object-Based Image Analysis(GEOBIA)and Data Mining(DM).In order to obtain the images,the segmentation algorithm implemented by Definiens Developer was used.A decision tree(DT)was created from a training set previously ***-series of images from the MODIS sensor aboard the Terra satellite were acquired in order to represent the wide variation of the vegetation pattern along the soybean crop *** time-series data were used only for the CEI ***,to compare the results obtained from GEOBIA,the slicing technique was used at the CEI *** the training,the DT was applied to the vegetation indices generating the thematic map of the spatial distribution of *** accordance with the error matrix and kappa parameter analysis,tests for statistical significance were *** indicate that the classification achieved by Kappa coefficients is *** short,the obtained results proved that combining vegetation indices and time-series data using GEOBIA return promising results for mapping soybean plantation on a regional scale.

关键词： GEOBIA time-series vegetation indices MODIS vegetation dynamics

Parameter Estimation for Hot-spot Thermal Model of Power Transformers Using Unscented Kalman Filters

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journal of Modern Power Systems and Clean Energy 2023年第2期11卷 634-642页

作者： MiguelÁngel González-Cagigal joséantonio Rosendo-Macías antonio Gómez-Expósito Department of Electrical Engineering University of SevilleSevilleSpain ENGREEN Laboratory of Engineering for Energy and Environmental Sustainability SevilleSpain

This paper presents a parameter estimation technique for the hot-spot thermal model of power *** proposed technique is based on the unscented formulation of the Kalman filter,jointly considering the state variables and parameters of the dynamic thermal model.A two-stage estimation technique that takes advantage of different loading conditions is developed,in order to increase the number of parameters which can be *** results are presented,which show that the observable parameters are estimated with an error of less than 3%.The parameter estimation procedure is mainly intended for factory testing,allowing the manufacturer to enhance the thermal model of power transformers and,therefore,its customers to increase the lifetime of these *** proposed technique could be additionally considered in field applications if the necessary temperature measurements are available.

关键词： Parameter estimation power transformer unscented Kalman filter thermal model