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Journal of Rare Earths 2020年第10期38卷 1131-1139,I0005页

作者： Eduardo S.Rodrigues Gabriel S.Montanha Joao P.R.Marques Eduardo de Almeida Lauren N.M.Yabuki amauri a.menegario Hudson W.Pereira de Carvalho Laboratory of Nuclear Instrumentation(LIN) Center for Nuclear Energy in Agriculture(CENA)University of Sao Paulo(USP)PiracicabaSP13416-000Brazil Environmental Studies Center Sao Paulo State University(UNESP)Rio ClaroSP13506-900Brazil

This study aims at investigating the effects of foliar application of aqueous solutions of La3+and Ce3+nitrates on soybean plants(Glycine max).First,we observe that Triton HW 1000 surfactant at 0.01 vol%reduces droplets contact angle and increases their drying *** greenhouse conditions,the foliar treatments do not affect chlorophyll content,plant height,number of leaves,number of pods,number of seeds per pod,and average seed ***,the treatments induce phytotoxicity since foliar injuries appear after the *** X-ray fluorescence spectroscopy combined to scanning electron microscopy shows that the leaf lesions are positively correlated to accumulation of Ce and La on the leaf surface and also promote structural alteration to the epidermal cells.X-ray absorption near edge structure shows that the La and Ce nitrates are partially bio transformed into oxides by the leaves which might explain the harmful effects.

关键词： Leaf fertilization Rare earth elements Soybean X-ray fluorescence spectroscopy X-ray absorption spectroscopy

Microstructural Morphologies and Experimental Growth Laws during Solidification of Monotectic and Hypermonotectic Al-Pb Alloys

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Journal of Materials Science & Technology 2014年第4期30卷 401-407页

作者： Adrina P.Silva amauri Garcia José E.Spinelli Department of Materials Engineering University of Campinas-UNICAMP Department of Materials Engineering Federal University of Sao Carlos-UFSCar

AI-Pb alloys with monotectic and hypermonotectic compositions were directionally solidified under unsteady- state heat flow conditions. The cooling curves recorded during solidification allowed solidification thermal parameters such as the cooling rate （T）, growth rate （v） and thermal gradient （G） to be experimentally determined. Different microstructural patterns have been associated with the alloy solute content, i.e., AI-1.2 and 2.1 wt% Pb. A sequence of morphologies from the bottom to the top of the A1-1.2 wt% Pb alloy casting （monotectic） can be observed： Pb-rich droplets in the aluminum-rich matrix, followed by a region of microstructural transition formed by droplets and fibers and finally by a mixture of fibers and strings of pearls. A completely fibrous structure （without transition） has been observed along the entire AI-2.1 wt% Pb alloy casting （hypermonotectic）. The interphase spacing （λ） was measured along the casting length, and experimental correlations between λand experimental solidification thermal parameters have been established. Power laws with a -2.2 exponent expressing λ as a function of the growth rate, v, were found to better represent the fibrous growth of both AI-Pb alloys. Moreover, a single experimental law expressing λ as a function of both G and v was found to describe the fibrous growth of both the monotectic and the hypermonotectic alloys experimentally examined.

关键词： Aluminum alloys Casting Phase transformation

Dendritic Growth, Eutectic Features and Their Effects on Hardness of a Ternary Sn–Zn–Cu Solder Alloy

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Acta Metallurgica Sinica(English Letters) 2017年第6期30卷 528-540页

作者： Bismarck Luiz Silva Rodrigo Valenzuela Reyes amauri Garcia JoséEduardo Spinelli Department of Materials Engineering Federal University of Rio Grande do Norte-UFRNNatalRN 59078-970Brazil Department of Materials Engineering Federal University of Sao Carlos-UFSCarSao CarlosSP 13565-905Brazil Department of Manufacturing and Materials Engineering University of CampinasUNICAMPCampinasSP 13083-860Brazil

The present investigation is based on the results of a directionally solidified （DS） Sn-9 wt%Zn-2 wt%Cu alloy, including primary/secondary/tertiary dendrite arm spacings of the Sn-rich matrix, the morphologies of the eutectic mixture and the corresponding interphase spacing, the nature and proportion of the Cu-Zn intermetallic compound （IMC）. The main purpose is to establish interrelations of these microstructure features with experimental solidification thermal parameters, such as cooling rates and growth rates （v）, macrosegregation and hardness. Such interrelations are interesting for both industry and academy since they represent a tool permitting the preprogramming of final properties based on the design of the microstructure. In the case of Sn-Zn-Cu alloys, hardly anything is known about the combined effects of the length scale of the microstructure and fraction and distribution of the primary IMC on hardness. The alloy microstructure is composed of a β-Sn dendritic region, surrounded by a eutectic mixture of α-Zn and β-Sn phases and the γ-Cu5Zn8 IMC. The eutectic interphase spacing varies in the range 1.2-3.6 μm, with the α-Zn phase having a globular morphology for ν 〉 0.5 mm/s and a needle-like morphology for ν 〈 0.3 mm/s. A modified Hall-Petch-type experimental expression relating hardness to the interphase spacing is proposed.

关键词： Sn-Zn-Cu solder alloy Solidification Microstructure Eutectic morphology Hardness

Effectiveness of traffic light system on Brazilian consumers perception of food healthfulness

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Food Science and Human Wellness 2019年第4期8卷 368-374页

作者： Mayara Lima Marcela de Alcantara amauri Rosenthal Rosires Deliza IT/DTA–Federal Rural University of Rio de Janeiro BR 465–Km 07CEP 23.890-000SeropédicaRJBrazil Nutrition and Dietetics Department–Federal Fluminense University Rua Mário Santos Braga30CEPNiteróiRJBrazil PDJ-CNPq/Embrapa Agroindústria de Alimentos Av.das Américas29501CEP 23.020-470Rio de JaneiroRJBrazil Embrapa Agroindústria de Alimentos Av.das Américas29501CEP 23.020-470Rio de JaneiroRJBrazil

Front-of-package(FOP)nutrition labelling schemes were developed to improve consumer’s comprehension about the food nutrients associated with non-communicable diseases(NCDs).Several FOPs have already been developed,and Brazil is in the process of evaluating a scheme to introduce in the *** aim of this study was to investigate the impact of TLS,the scheme proposed by the food industry,on the product healthfulness perception.A study with 141 participants was carried out.A conjoint task was designed considering three categories and levels:types of dairy products(light yogurt,prato cheese,and chocolate flavoured milk),Traffic Light System(yes ***)and brand(well-known ***).The effect of TLS on perceived healthfulness was evaluated using a 9-point scales(1:not healthy;9:very healthy).Results showed that the inclusion of TLS did not influence the perceived healthfulness of the products by consumers,even among consumers with higher interest in healthy *** findings suggest that the proposal supported by the food industry does not seem to be the most appropriate,being recommended the development of further studies to compare the efficacy of TLS and other FOP schemes.

关键词： Front of pack Traffic light system Healthfulness perception Food products

Corrosion behavior of hypoeutectic Al-Cu alloys in H_2SO_4 and NaCl solutions

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Acta Metallurgica Sinica(English Letters) 2009年第4期22卷 241-246页

作者： Wislei R.Osório Leandro C.Peixoto Leonardo R.Garcia amauri Garcia Department of Materials Engineering University of Campinas-UNICAMP

The aim of this work was to evaluate the electrochemical behaviour of hypoeutectic Al-Cu alloys immersed in two different solutions containing sulphate and chloride ions, respectively. The influence of Al2Cu associated to the dendritic arm spacing on the general corrosion resistance of such alloys is analysed. The typical microstructural pattern was examined by using scanning electron microscope. The corrosion tests were performed in both 0.5 M sulphuric acid and 0.5 M NaCl solutions at 25℃ by using an electrochemical impedance spectroscopy （EIS） technique and potentiodynamic polarization curves. Equivalent circuits by using the ZView software, were also used to provide quantitative support for the discussions. It was found that as the Cu content increased （i.e., increasing the Al2Cu fraction）, a higher susceptibility to the corrosion action in the NaCl solution is detected. In contrast, the tests carried out in the H2SO4 solution resulted in similar corrosion,rates for the three different hypoeutectic alloys.

关键词： Al-Cu alloys Al2Cu Corrosion Microstructure Castings

Horizontally Solidified Al-3 wt%Cu-(0.5 wt%Mg)Alloys:Tailoring Thermal Parameters,Microstructure,Microhardness,and Corrosion Behavior

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Acta Metallurgica Sinica(English Letters) 2019年第6期32卷 695-709页

作者： Andre Barros Clarissa Cruz Adrina P.Silva Noe Cheung amauri Garcia Otavio Rocha Antonio Moreira Institute of Technology Federal University of Para-UFPABelemPA 66075-110Brazil Federal Institute of Education Science and Technology of Para-IFPABelemPA 66093-020Brazil Department of Manufacturing and Materials Engineering University of Campinas-UNICAMPCampinasSP 13083-860Brazil

In the present experimental investigation,Al–3 wt%Cu and Al–3 wt%Cu–0.5 wt%Mg alloys castings are produced by a horizontal solidification technique with a view to examining the interrelationship among growth rate(GR),cooling rate(CR),secondary dendrite arm spacing(λ2),Vickers microhardness(HV),and corrosion behavior in a 0.5 M NaCl *** intermetallic phases of the as-solidified microstructures,that is,h-Al2Cu,S–Al2CuMg,and x-Al7Cu2 Fe,are subjected to a comprehensive characterization by using calculations provided by computational thermodynamics software,optical microscopy,and scanning electron microscopy/energy-dispersive ***,electrochemical impedance spectroscopy and potentiodynamic polarization tests have been applied to analyze the corrosion performance of samples of both alloys ***–Petch-type equations are proposed to represent the HV dependence onλ*** is shown that the addition of Mg to the Al–Cu alloy has led to a considerable increase in HV;however,the Al–Cu binary alloy is shown to have lower corrosion current density(icorr)as well as higher polarization resistance as compared to the corresponding results of the Al–Cu–Mg ternary alloy.

关键词： Aluminum alloys Solidification Dendritic microstructure Intermetallic phases Microhardness Corrosion resistance

Mobile Robot Autonomous Environment Perception and Navigation in Indoor Environments

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Mobile Robot Autonomous Environment Perception and Navigatio...

作者： amauri Bueno de Camargo Junior（马祥瑞）大连理工大学

学位级别：硕士

This dissertation presents recent research on the problem of environmental modeling for exploration,localization and map building for a fully autonomous and self-contained mobile *** robots acting in an indoor building *** have a multi-sensor setup where encoders are used to extract the odometry data and a front positioned 2D Light Detection and Ranging(LiDAR)sensor are employed to perceive the *** to study mobile robot exploration,localization and mapping,the work begins with the research around techniques to register the environment with laser scans besides the dynamically and statically noise presence,followed by the propose of different architecture systems allowing two types of mapping to be merged to find the localization of the *** system presents the possibility of creating small map data files to register the *** low data density favors the efficiency enhancement during data *** representation of the environment around is critical for mobile robot *** task defines which perception capabilities are needed and which navigation technique is permitted to *** present environmental modeling register is both in metric and topological *** coherently combining the two well-known technics,advantages of both approaches are added to confront the drawbacks of a single *** capability of the hybrid system is exploited to model an indoor building environment where the metric information is used locally inside the “Rolling Dynamical Window”.This format is constrained to the robot surroundings while the topology of the whole environment is accurate separately,resulting in avoiding the need for global metric *** maps register just enough information to create the topological nodes and edges in a relational *** allows the mobile robot to use the neighbor's topological relations in navigation,which reduces the resulting path after the route *** hybri

关键词： Exploration Navigation Indoor environments 2D LiDAR

Microstructure features and mechanical/electrochemical behavior of directionally solidified Al−6wt.%Cu−5wt.%Ni alloy

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Transactions of Nonferrous Metals Society of China 2021年第6期31卷 1529-1549页

作者： Adilson Vitor RODRIGUES Thiago Soares LIMA Talita Almeida VIDA Crystopher BRITO amauri GARCIA Noé CHEUNG Department of Manufacturing and Materials Engineering University of Campinas-UNICAMPCampinasSP13083-860Brazil Federal Institute of Education Science and Technology of São Paulo-IFSPBragança PaulistaSP12903-600Brazil São Paulo State University-UNESP Campus of São João da Boa VistaSão João da Boa VistaSP13876-750Brazil

The effects of the addition of 5.0 wt.%Ni to an Al−6wt.%Cu alloy on the solidification cooling rate(T),growth rate(V_(L)),length scale of the representative phase of the microstructure,morphology/distribution of intermetallic compounds(IMCs)and on the resulting properties were *** and tensile properties were determined on samples solidified under a wide range of T along the length of a directionally solidified Al−6wt.%Cu−5.0wt.%Ni alloy *** growth laws were derived relating the evolution of primary(λ_(1))and secondary(λ_(2))dendritic spacings with T and V_(L).The elongation to fracture(δ)and the ultimate tensile strength(σ_(U))were correlated with the inverse of the square root of λ_(1) along the length of the casting by Hall−Petch type experimental *** reinforcing effect provided by the addition of Ni in the alloy composition is shown to surpass that provided by the refinement of the dendritic *** highest corrosion resistance is associated with a microstructure formed by thin IMCs evenly distributed in the interdendritic regions,typical of samples that are solidified under higher T.

关键词： Al−Cu−Ni alloys as-cast microstructures dendritic spacings tensile properties corrosion resistance

Tailoring microstructure and microhardness of Zn-1wt.%Mg-(0.5wt.%Mn, 0.5wt.%Ca) alloys by solidification cooling rate

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Transactions of Nonferrous Metals Society of China 2021年第4期31卷 1031-1048页

作者： Talita A.VIDA Cássio A.P.SILVA Thiago S.LIMA NoéCHEUNG Crystopher BRITO amauri GARCIA Department of Manufacturing and Materials Engineering University of Campinas-UNICAMPCampinas 13083-860SPBrazil Campus of São João da Boa Vista São Paulo State University-UNESPSão João da Boa Vista 13876-750SPBrazil

Biodegradable Zn-based alloys, particularly Zn-Mg alloys with the addition of alloying elements, have been intensively investigated aiming to improve both mechanical properties and corrosion behavior. Since such properties are strongly dependent on the alloy microstructure, any evaluation should commence on understanding the conditions influencing its formation. In this study, the effect of the solidification cooling rate on the microstructural evolution of Zn-1 wt.%Mg-(0.5 wt.%Ca, 0.5 wt.%Mn) alloys during transient solidification was investigated. The results show that the microstructures of both alloys have three phases in common: η-Zn dendritic matrix, intermetallic compounds(IMCs) Zn11Mg2, and Zn2 Mg in the eutectic mixture. MnZn9 and two Ca-bearing phases(CaZn11 and CaZn13) are associated with Mn and Ca additions, respectively. These additions are shown to refine the dendritic matrix and the eutectic mixture as compared to the Zn-1 wt.%Mg alloy. A correlation between cooling rate, dendritic or eutectic spacings was developed, thus permitting experimental growth laws to be proposed. Additionally, hardness tests were performed to evaluate the effects of additions of Ca and Mn. Experimental correlations between Vickers microhardness and secondary dendritic spacings were proposed, showing that the microstructural refinement and characteristic Ca and Mn based IMCs induce an increase in hardness as compared to the binary alloy.

关键词： Zn-Mg-(Ca Mn)alloys solidification cooling rate microstructure microhardness

Diagnostic of the diurnal cycle of turbulence of the Equatorial Atlantic Ocean upper boundary layer

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Natural Science 2011年第6期3卷 444-455页

作者： Udo T.Skielka Jacyra Soares amauri P.Oliveira Jacques Servain Department of Atmospheric Sciences University of Sao PauloSao PauloBrazil Institut de Recherche pour le Developpement(IRD) ParisFrance

This work is an attempt to diagnose the turbu-lence field of the equatorial Atlantic Ocean dur-ing the dry period when the mixed layer is more highly developed using the General Ocean Turbulence Model (GOTM). A relaxation scheme assimilates the vertical profiles of in situ ob-servations (current velocity, sea temperature and salinity) during simulations. In the absence of direct turbulence observations and modeling studies of the equatorial Atlantic Ocean, the results are compared qualitatively to observed and simulated results for the equatorial Pacific Ocean. Similarities are noted between the At-lantic simulation and previous studies per-formed in the Pacific Ocean. The mechanism of nocturnal turbulence production, namely deep- cycle turbulence, is well captured by GOTM si-mulations. This deep nocturnal turbulence ap-pears rather suddenly during the night in the simulations and consequently seems to be un-related to surface wind and radiation forcing.

关键词： Oceanic Boundary Layer Oceanic Turbulence Tropical Oceanography Equatorial Atlantic Ocean