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Miscibility of Poly(hydroxybutyrate)/Poly(vinyl alcohol)Melt Blends Plasticized With Glycerol

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Journal of Renewable Materials 2019年第4期7卷 325-333页

作者： Deliane da silva Cabral antonio JoséFelix Carvalho Department of Materials Engineering São Carlos School of EngineeringUniversity of São PauloAv.João Dagnone110013563-120São Carlos-SP-Brazil

Poly(hydroxybutyrate)/poly(vinyl alcohol)(PHB/PVA)blends plasticized with glycerol were prepared by melt blending of PHB and glycerol plasticized *** PHB/PVA-glycerol compositions were 90:10,75:25 and 50:50 w/w,being the concentration of glycerol in the PVA mixture of 10 wt%.The blends were characterized by infrared spectroscopy,dynamic-mechanical thermal analysis,and scanning electron microscope of the fragile fractured *** results showed one single phase blend,indicating miscibility corroborated by the presence of a single glass transition *** blending method proved to be an efficient way to tune PHB properties keeping its biodegradable nature since both PVA and glycerol are fully biodegradable materials.

关键词： Blend miscibility melt processing poly(hydroxybutyrate) poly(vinyl alcohol)

A Finite Element Study of the Influence of Graphite Nodule Characteristics on a Subsurface Crack in a Ductile Cast Iron Matrix under a Contact Load

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Computer Modeling in Engineering & Sciences 2018年第10期117卷 59-71页

作者： Guilherme Suguinoshita Carlos Henrique da silva Marco antonio Luersen Department of Mechanical Engineering Federal University of Technology-Parana(UTFPR)Rua Deputado Heitor Alencar Furtado5000CEP 81280-340CuritibaBrazil

This paper describes a study of the effects of graphite nodule characteristics on a subsurface crack in austempered ductile iron(ADI).A representative specimen of ADI,subjected to sliding contact load,is modeled using finite elements aiming to obtain the shear stress intensity factor(KII).The parameters varied were(i)the nodule diameter(two different values were considered),(ii)the distance between the nodule and the tip of the crack and(iii)the position of the load relative to the tip of the *** results of the numerical simulations show that the smaller diameter nodule has a larger influence on KII,suggesting a higher contact fatigue crack propagation rate in the material with the smaller *** results are the opposite of those observed in experimental studies and would appear to indicate that other factors should be also considered to ensure realistic estimates of the contact fatigue strength of ADI.

关键词： Austempered ductile iron subsurface crack stress intensity factor finite element analysis graphite nodule

Equity issues and the PeCUS index:an indirect analysis of community severance

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Geo-Spatial Information Science 2020年第4期23卷 293-304页

作者： daniela Vanessa Rodriguez Lara antonio Nelson Rodrigues da silva Department of Transportation Engineering São Carlos School of EngineeringUniversity of São PauloSão PauloBrazil

Urban barriers are often a consequence of the unplanned expansion of transport infrastructures,housing growth nearby existing transport infrastructures,and the vehicular traffic *** process,also known as“community severance”,is a problem that affects the travel patterns of the population and causes negative impacts to adjacent communities,but it is not easy to *** an alternative to the costly technologies and restricted-access data sometimes used to analyze urban barriers,we propose an analytical approach that assesses community severance levels by classifying the quality of Pedestrian Crossings on Urban Streets(the PeCUS index).Additionally,the approach is used to identify possible inequities nearby the different classification groups regarding demographic *** used the chi-square(χ^(2))test of independence and the standardized Pearson residuals to indicate deficits and excesses of residents regarding the demographic characteristics studied surrounding the urban *** found the following evidences of associations:residents with low-income or those aged up to 19 tend to live close to the worst crossings,whereas residents with permanent mobility constraints or the elderly tend to live near the crossings with the best ***,the study shows that the assessment of community severance by the analysis of the PeCUS index is ***,it reveals that the distribution of residents surrounding the distinct classes of quality of crossings is equitable for vulnerable social groups,except for low-income or young residents.

关键词： Community severance transport barriers pedestrian crossings equity open data geographic information systems(GIS)

Special Issue on 15th Brazilian Polymer Conference:Biopolymers,Eco-Friendly and Biodegradable Polymers and Other Topics Related to Polymeric Materials Derived from Renewable Materials

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Journal of Renewable Materials 2021年第4期9卷 599-600页

作者： antonio Aprigio da silva Curvelo antonio José Felix Carvalho daniel Pasquini São Carlos Institute of Chemistry University of São PauloSão Carlos13566-590-SPBrazil São Carlos School of Engineering University of São PauloSão Carlos13563-120-SPBrazil Institute of Chemistry Federal University of UberlândiaUberlândia38400-902MGBrazil

This issue of Journal of Renewable Materials is a special issue dedicated to the 15th Brazilian Polymer Conference(15th CBPol)which was held in Bento Gonçalves,Rio Grande do Sul State,Brazil,from 27 to 31 October,2019[1].CBPol is the main scientific forum in the field of polymer science and technology in *** conference has been held biannually since 1991 and in this event had almost 900 participants mainly from Brazil,but also from Argentina,Chile,Peru,USA,Canada,Belgium,France,Great Britain,Portugal and Spain,with 60%students and 40%professionals.A total of 1,100 papers from 2725 authors were presented,from which 25%(280 papers)was in the field of Biomaterials showing the importance of these materials which are in general based on renewable *** 280 works were developed mainly by researchers from Brazilian institutions(universities and research institutes),mainly from the south and southeast regions of the *** subject of more than 70%of the works was dedicated on vegetal raw materials,medicinal applications,packaging and composite materials.

关键词： materials showing annually

19-year remotely sensed data in the forecast of spectral models of the environment

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International Journal of Digital Earth 2021年第8期14卷 1040-1066页

作者： Fernando Saragosa Rossi Carlos antonio da silva Junior JoséFrancisco de Oliveira-Júnior Paulo Eduardo Teodoro Luciano Shozo Shiratsuchi Mendelson Lima Larissa Pereira ribeiro Teodoro Auana Vicente Tiago Guilherme Fernando Capristo-silva State University of Mato Grosso(UNEMAT) Alta FlorestaMato GrossoBrazil Department of Geography State University of Mato Grosso(UNEMAT)SinopMato GrossoBrazil cFederal University of Alagoas(UFAL) MaceióAlagoasBrazil dFederal University of Mato Grosso do Sul(UFMS) Chapadão do SulMato Grosso do SulBrazil eAgCenter School of PlantEnvironmentaland Soil SciencesLouisiana State University(LSU)Baton RougeLouisianaUSA fPostgraduate Program in Agronomy Federal University of Mato Grosso(UFMT)SinopMato GrossoBrazil

The aims of this study were:i)to compare no-till areas in two municipalities located in different regions of Brazil,along with the influence on CO_(2)Flux and GPP,and ii)to verify the difference between environmental factors followed by the trends of these variables regarding future scenarios(ARIMA time-series model number).The study was carried out in two areas with different latitudes in the municipalities of Sinop-MT and Passo Fundo-RS,both in Brazil.A time series of 19 years was performed with data acquired by remote sensing from the following satellites:i)Landsat-8(OLI and TIRS),and ii)TERRA/AQUA(MODIS).The results propound that the spectro-temporal variables are directly influenced by soil management and agricultural practices over the observation time,with a satisfactory correlation in future predictions of the variables for the next ten years,in which presented that the variation of GPP and albedo values for the two study sites would gradually increase until 2028 and the temperature remained constant between the range of its seasonality,and CO_(2)Flux tends to decrease in its seasonality,indicating a higher CO_(2) absorption.

关键词： ARIMA numerical modeling remote sensing orbital products tillage

Pulp and Paper from Sugarcane:Properties of Rind and Core Fractions

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Journal of Renewable Materials 2018年第2期6卷 160-168页

作者： Lísias Pereira Novo Julien Bras Mohamed Naceur Belgacem antonio Aprigio da silva Curvelo Department of Materials Engineering Sao Carlos School of EngineeringUniversity of Sao PauloAv.Joao Dagnone 110013563-120Sao CarlosSao PauloBrazil Department of Physical Chemistry Sao Carlos Institute of ChemistryUniversity of Sao PauloAv.Trabalhador Sao Carlense 40013560-970Sao CarlosSao PauloBrazil Grenoble Alpes University LGP2F-38000 GrenobleFrance CNRS LGP2F-38000 GrenobleFrance

Two distinct lignocellulosic fractions(rind and core)can be obtained through a physical separation of sugarcane *** presenting differences in morphology,both fractions can be employed to produce pulps and *** pulps and paper sheets produced from the core and rind fractions were characterized by their chemical composition,physical properties and mechanical *** pulps obtained from the core presented a higher amount of fines,lower drainage ability and rendered denser and stiffer *** pulps from the rind,which have a higher content of fibers and higher degree of polymerization,produced sheets with higher air permeability and water *** paper sheets presented mechanical and physical properties comparable to commercial papers and papers from different cellulosic *** different properties exhibited by the papers produced from each fraction allow their use for distinct purposes,and expands the opportunities in the context of sugarcane biorefinery.

关键词： Sugarcane core and rind fractions papermaking pulp and paper

Multi-stage block freeze concentration via gravitational method applied to increase of the nutritional content of Morinda citrifolia ***

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Food Bioscience 2023年第1期51卷 985-994页

作者： Edipo da silva Almeida Mateus antonio Knapp Juliana De Gregori da Rocha dachamir Hotza Debora de Oliveira Department of Chemical Engineering and Food Engineering(EQA) Federal University of Santa Catarina(UFSC)88040-970FlorianopolisSCBrazil

The processing of Morinda citrifolia fruit normally results in a large number of waste leaves that hold many bioactive compounds with nutritional and pharmacological *** work aimed to evaluate the effects of a multi-stage block freeze concentration(BFC)via gravitational method on the physicochemical properties of the leaf extract(noni tea).The results in solid retention showed fractions almost 7 times most concentrated than the initial *** addition,when compared to the initial content,the BFC process showed an efficiency higher than 90%in the retention of phenolic *** in liquid chromatography allowed the detection and quantification of phenolic compounds,in which the total amount increased by more than 1000%in relation to the initial content after each BFC ***,it was also possible to observe a significant increase in the antioxidant activity of the concentrated product after the simulated in vitro digestion *** was concluded that using a non-thermal,sustainable,low-cost processing,promoted the obtaining of concentrated fractions with high biological and nutritional values with promising properties for application in the development of functional foods from agroindustrial wastes.

关键词： Morinda citrifolia Block freeze concentration Phenolic compounds Antioxidant profile In vitro digestion Functional food

A Bidimensional Finite Element Study of Crack Propagation in Austempered Ductile Iron

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Computers, Materials & Continua 2023年第11期77卷 1411-1424页

作者： Gustavo von Zeska de França Roberto Luís de Assumpção Marco antonio Luersen Carlos Henrique da silva Department of Mechanical Engineering Federal University of Technology–ParanáCuritiba81280-340Brazil

Austempered ductile iron(ADI)is composed of an ausferritic matrix with graphite nodules and has a wide range of applications because of its high mechanical strength,fatigue resistance,and wear resistance compared to other cast *** amount and size of the nodules can be controlled by the chemical composition and austenitizing *** the nodules have lower stiffness than the matrix and can act as stress concentrators,they influence crack ***,the crack propagation mechanism in ADI is not yet fully *** this study,we describe a numerical investigation of crack propagation in ADIs subjected to cyclic *** numerical model used to calculate the stress intensity factors in the material under the given conditions is built with the aid of Abaqus commercial finite element *** crack propagation routine,which is based on the Paris law,is implemented in *** results of the simulation show that the presence of a nodule generates a shear load on the crack ***,even under uniaxial tensile loading,the presence of the nodule yields a non-zero stress intensity factor in mode II,resulting in a deviation in the crack propagation *** is the primary factor responsible for changing the crack propagation direction towards the *** the parameters,for example,increasing the nodule size or decreasing the distance between the nodule and crack tip,can intensify this *** simulations comparing two different ADIs with the same graphite fraction area,the crack in the material with more nodules reaches another nodule in a shorter propagation time(or shorter number of cycles).This suggests that the high fatigue resistance observed in ADIs may be correlated with the number of nodules intercepted by a crack and the additional energy required to nucleate new *** summary,these findings contribute to a better understanding of crack propagation in ADIs,provide insights into the relationship between the presence

关键词： Austempered ductile iron(ADI) fatigue crack propagation graphite nodule

Effectiveness of different biochars in remediating a salt-affected Luvisol in Northeast Brazil

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Biochar 2021年第2期3卷 149-159页

作者： Wallace Melo dos Santos Maria Isidoria silva Gonzaga JoséAiron da silva AndréQuintão de Almeida JoséCarlos de Jesus Santos Thomas antonio silva Gonzaga Idamar da silva Lima EloáMoura Araújo Water Resources Graduate Program Federal University of SergipeSão CristóvãoSE 49100‑000Brazil Agronomy Department Federal University of SergipeSão CristóvãoSE 49100‑000Brazil Agriculture Engineering Department Federal University of SergipeSão CristóvãoSE 49100‑000Brazil University of Notre dame Notre DameIN 46556USA Soils and Agricultural Engineering Department Federal University of ParanáCuritibaPR 80060‑000Brazil

Biochar has been proposed as a soil amendment to reclaim salt-affected ***,the evaluation of the different biochar types in these soils is essential due to the significant variation among biochar *** this study,biochars from sugarcane bagasse(SB),orange bagasse(OB),and corncob(CB)were applied alone and in the presence of gypsum(G)to test their potential to remediate a highly degraded saline-sodic soil in Brazil´s Northeast *** that,we conducted a laboratory column-leaching experiment and a greenhouse *** the column-leaching test,we analyzed the sodium adsorption ratio(SAR),the electrical conductivity of the saturation extract(ECe),the concentrations of major ions,and the exchangeable sodium percentage(ESP).Maize plants were grown in the leached soil in a ***-and corncob-derived biochars were more efficient than gypsum in reducing the soil salinity,bringing the indicators below threshold values,and optimizing soil reclamation *** ECe,SAR,and ESP were reduced to 3.42 dS m−1,1.64(mmolc dm−3)0.5 and 4.86%,respectively,in the SB treatment;and to 3.19 dS m−1,0.88(mmolc dm−3)0.5 and 2.53%,respectively,in the CB *** bagasse biochar did not effectively reduce the salinity *** biochar treatments improved seed germination and plant *** SB,CB,SBG,and CBG treatments increased plant height(478–558%),shoot mass(783–983%),and root mass(386–500%),***,the application of SB and CB is an effective alternative to remediate saline-sodic soils and to reduce the impact of soil salinity in the environment.

关键词： Biochar Soil remediation Soil salinity Corn growth