Matéria (Rio de Janeiro)最新文献_第3页

Fracture mechanics analysis of a fatigue failure of a parabolic spring 抛物型弹簧疲劳破坏的断裂力学分析

Matéria (Rio de Janeiro) Pub Date : 2023-08-21 DOI: 10.1590/1517-7076-rmat-2023-0115

M. Chapetti, B. Senčič, N. Gubeljak

引用次数: 0

Matéria (Rio de Janeiro) Pub Date : 2023-08-18 DOI: 10.1590/1517-7076-rmat-2023-0068

C. Costa, Sandra Raquel Kunst, Tamires Lovato, Eduardo Luis Schneider, Cláudia Trindade Oliveira

{"title":"Selagem de zamac anodizado","authors":"C. Costa, Sandra Raquel Kunst, Tamires Lovato, Eduardo Luis Schneider, Cláudia Trindade Oliveira","doi":"10.1590/1517-7076-rmat-2023-0068","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0068","url":null,"abstract":"RESUMO Estudos já demonstraram que a anodização de zamac é uma alternativa para minimizar os efeitos corrosivos da liga. Outros estudos, em alumínio, demonstraram que quando anodizado e selado pelo processo à quente, promove aumento da sua resistência à corrosão. No entanto, não se tem relatos na literatura sobre selagem à quente em zamac anodizado. O objetivo deste trabalho é identificar o efeito da selagem, quanto a resistência de corrosão, sobre zamac anodizado. Para tanto, peças de zamac 5 lixadas e polidas industrialmente foram anodizadas em eletrólito 0,3 M de ácido oxálico em diferentes tempos (5, 30 e 60 minutos), e posteriormente seladas em H2O destilada à 90ºC por uma hora. As peças foram analisadas por técnicas morfológicas e de corrosão. Os resultados mostraram que com o aumento do tempo de anodização os cristalitos maiores dissolvem-se originando cristalitos menores até a formação de camada lisa. Além disso, o processo de selagem promoveu a hidratação dos produtos anodizados do zamac. No entanto, com o aumento do tempo de anodização, a camada de óxido ficou mais compacta, devido aos menores cristalitos, com diminuição da espessura, devido à camada lisa. Isso resultou no melhor desempenho anticorrosivo da amostra anodizada por 5 minutos e selada.","PeriodicalId":18246,"journal":{"name":"Matéria (Rio de Janeiro)","volume":"1217 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80341129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of the pressure on the interaction between stearic acid and Ar-O2 in inductively coupled radio frequency plasma 压力对电感耦合射频等离子体中硬脂酸与Ar-O2相互作用的影响

Matéria (Rio de Janeiro) Pub Date : 2023-08-18 DOI: 10.1590/1517-7076-rmat-2023-0070

E. A. Bernardelli, Fernanda Splett, Carlos Eduardo Farias, R. Villanova, M. Mafra

{"title":"Influence of the pressure on the interaction between stearic acid and Ar-O2 in inductively coupled radio frequency plasma","authors":"E. A. Bernardelli, Fernanda Splett, Carlos Eduardo Farias, R. Villanova, M. Mafra","doi":"10.1590/1517-7076-rmat-2023-0070","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0070","url":null,"abstract":"This work aimed to analyze the influence of treatment pressure on the interaction between stearic acid and an Argon-Oxygen plasma. The fixed variables were the applied RF plasma power (50 W), treatment time (30 min), and treatment starting temperature (273 K). The pressure was varied as follows: 0.2, 0.6, and 1.0 Torr. For all treatment conditions, the etching of the samples was observed, as evidenced by the mass loss of the specimens and by following the gaseous by-products of reactions employing a mass spectrometer coupled to the reaction chamber. Optical emission spectroscopy followed the emission lines of oxygen active species. Function-alization of the specimens was also observed, as shown by the results obtained by Fourier-transform infrared spectroscopy (FTIR) and through XRD analysis. A liquid phase was formed for samples treated at 0.6 and 1.0 Torr, which favored the functionalization process and broadened the band present in the region from 1750 to 1700 cm –1 , resulting in amorphous phases. An increase in the intensity of the characteristic peaks of esters was also observed. It can be concluded that the higher pressure favors the formation of a liquid phase and reaction kinetics, resulting in higher functionalization and lower etching","PeriodicalId":18246,"journal":{"name":"Matéria (Rio de Janeiro)","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82362727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Estudo da adição de fibras kraft (embalagens de cimento recicladas) nas propriedades químicas e microestruturais de matrizes cimentícias 添加牛皮纸纤维(再生水泥包装)对胶凝基质化学和微观结构性能的研究

Matéria (Rio de Janeiro) Pub Date : 2023-08-14 DOI: 10.1590/1517-7076-rmat-2023-0065

L. Alves, C. H. Pereira, Ênio José Pazini Figueiredo

{"title":"Estudo da adição de fibras kraft (embalagens de cimento recicladas) nas propriedades químicas e microestruturais de matrizes cimentícias","authors":"L. Alves, C. H. Pereira, Ênio José Pazini Figueiredo","doi":"10.1590/1517-7076-rmat-2023-0065","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0065","url":null,"abstract":"RESUMO O trabalho tem como objetivo a caracterização química e microestrutural dos compósitos, verificando o índice de inibição das fibras vegetais com a matriz cimentícia, sua interferência na hidratação do cimento Portland, a composição química da fibra e do compósito, e possíveis processos de degradação da fibra na matriz. As matérias-primas utilizadas para formar os compósitos incluíram: cimento Portland, fibras kraft e água. Foram avaliados diferentes teores de adição de fibras kraft (referência, 0,5%, 1,0% e 3,0%) em relação a massa de cimento e três relações água/cimento (0,40; 0,45 e 0,50). Foi possível avaliar a interferência das fibras kraft na hidratação do cimento Portland, sendo essa classifica da como baixa inibição, demonstrando a compatibilidade das fibras com a matriz cimentícia de acordo com as análises realizadas. Em relação à temperatura não foram constatadas grandes diferenças que evidenciassem um retardo da hidratação devido os componentes inibitórios da fibra vegetal, assim como não foi detectado processo de degradação das fibras kraft (mineralização).","PeriodicalId":18246,"journal":{"name":"Matéria (Rio de Janeiro)","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78118289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Research on an acoustic judgment method for the incipient cavitation of model hydraulic machinery runner blades 模型水工机械流道叶片早期空化的声学判断方法研究

Matéria (Rio de Janeiro) Pub Date : 2023-08-04 DOI: 10.1590/1517-7076-rmat-2023-0154

Wentao Su, Weijun Meng, Yue Zhao, Jian Wu, Yuekun Sun

{"title":"Research on an acoustic judgment method for the incipient cavitation of model hydraulic machinery runner blades","authors":"Wentao Su, Weijun Meng, Yue Zhao, Jian Wu, Yuekun Sun","doi":"10.1590/1517-7076-rmat-2023-0154","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0154","url":null,"abstract":"The cavitation phenomenon is an important factor affecting the safe and stable operation of hydraulic machinery units. The cavitation of the hydraulic machinery units can lead to the increased vibration, reduced efficiency, and cavitation erosion of blades. Therefore, a method is needed to determine the incipient cavitation of hydraulic machinery runner blades. This study is initiated from the acoustic characteristics of bubbles generated by the cavitation of model hydraulic turbines and the characteristics of radiated sound energy during cavitation. The characteristics of cavitation noise are studied. After the qualitative analysis of the high-and low-frequency energy distribution patterns of cavitation noise signals before and after cavitation, a mathematical model of the time-frequency characteristics of these signals is proposed using the energy distribution analysis method. The feature information is extracted from the cavitation noise signals and used to judge the occurrence of incipient cavitation in model turbine runner blades. Based on this method, an online cavitation monitoring system is constructed, and comparative tests are carried out on a model pump turbine and Francis turbine. It is found that the results of the proposed method for the judgment of incipient cavitation are highly consistent with those of traditional methods.","PeriodicalId":18246,"journal":{"name":"Matéria (Rio de Janeiro)","volume":"78 4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74588493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

From coconut waste to the production of cementitious composites as an alternative for civil construction 从椰子废料到生产胶凝复合材料作为民用建筑的替代品

Matéria (Rio de Janeiro) Pub Date : 2023-08-04 DOI: 10.1590/1517-7076-rmat-2023-0146

Fernanda Monique da Silva, M. V. Scatolino, Edgley Alves de Oliveira Paula, V. G. O. Almeida, Felipe Bento de Albuquerque, Ricardo Alan da Silva Vieira, Joalis Barbalho de Souza, T. D. Pedrosa, Francisco Rodolfo Junior, R. Melo

{"title":"From coconut waste to the production of cementitious composites as an alternative for civil construction","authors":"Fernanda Monique da Silva, M. V. Scatolino, Edgley Alves de Oliveira Paula, V. G. O. Almeida, Felipe Bento de Albuquerque, Ricardo Alan da Silva Vieira, Joalis Barbalho de Souza, T. D. Pedrosa, Francisco Rodolfo Junior, R. Melo","doi":"10.1590/1517-7076-rmat-2023-0146","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0146","url":null,"abstract":"Economic development based on cleaner industrial technologies has been increasingly studied in recent years. Cementitious composites reinforced with lignocellulosic fibers can be a sustainable alternative for use in engineering. The study aimed to evaluate the technological properties of cementitious composites produced from natural and industrial coconut fiber to compare the reinforcement with wood particles. Physical tests (density, water absorption, and thickness swelling) and mechanical tests (static bending) were carried out in four treatments, which varied the fiber and cement contents. It was found that treatment with natural coconut fiber had the lowest density value, 0.59 g/cm 3 , and treatment with industrial coconut fiber had the lowest water absorption value for the times and times of 2 and 24 h, 0.19, and 0.38%, respectively, and the treatment with wood particles, the highest values of modulus of elasticity and rupture, 1,897 MPa and 2.44 MPa. The study of the use of lignocellulosic materials as protection in cementitious composites is essential for applications in building constructions to reduce the environmental impacts generated by the generation of waste and use of non-renewable materials and to promote sustainable development.","PeriodicalId":18246,"journal":{"name":"Matéria (Rio de Janeiro)","volume":"83 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76549805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An experimental study on strength and durability properties of self-compacting and self-curing concrete using light weight aggregates 轻骨料自密实自养护混凝土强度耐久性试验研究

Matéria (Rio de Janeiro) Pub Date : 2023-08-04 DOI: 10.1590/1517-7076-rmat-2023-0156

Syed Abdhaheer Kadhar, E. Gopal, V. Sivakumar

引用次数: 0

Viabilidade do uso de madeira clonal de Eucalyptus urophylla de rápido crescimento para produção de madeira lamelada colada (MLC) com adesivo poliuretano à base de mamona 利用尾叶桉无性系木材快速生长生产蓖麻基聚氨酯胶合层压木材的可行性

Matéria (Rio de Janeiro) Pub Date : 2023-07-31 DOI: 10.1590/1517-7076-rmat-2023-0073

Melissa Lago de Jesus Silveira Silva, M. Lobo, Rita Dione Araújo Cunha, S. César

{"title":"Viabilidade do uso de madeira clonal de Eucalyptus urophylla de rápido crescimento para produção de madeira lamelada colada (MLC) com adesivo poliuretano à base de mamona","authors":"Melissa Lago de Jesus Silveira Silva, M. Lobo, Rita Dione Araújo Cunha, S. César","doi":"10.1590/1517-7076-rmat-2023-0073","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0073","url":null,"abstract":"RESUMO A Madeira Lamelada Colada (MLC) é uma alternativa viável para o aproveitamento racional da madeira, possibilitando o uso de madeiras jovens. Ainda, ao engenheirar a madeira, pode-se viabilizar o uso de troncos de menor qualidade e menor diâmetro. Entretanto, o desempenho do produto depende da espécie utilizada, das espessuras e posições das lamelas, do tipo de adesivo, do desempenho da colagem. Este trabalho teve como objetivo estudar a viabilidade do uso de uma madeira de rápido crescimento para a produção de MLC. A espécie de madeira selecionada foi Eucalyptus urophylla, clonal COP 1404, que se caracteriza por ter rápido crescimento e por ter uma lacuna em estudos que visam sua aplicação na construção civil. Empregou-se o adesivo poliuretano bicomponente à base de óleo mamona. O programa experimental teve como foco a caracterização da madeira in natura e o desempenho mecânico da MLC comparada à madeira maciça, empregando métodos estatísticos para a análise de resistência dos protótipos. Os resultados indicaram que o adesivo foi eficiente na colagem da madeira, de modo que o cisalhamento ocorreu na madeira, além da verificação à flexão ter mostrado comportamento de um corpo único, não tendo pontos de descontinuidade por conta da linha de cola.","PeriodicalId":18246,"journal":{"name":"Matéria (Rio de Janeiro)","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84648614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Developing an easy-to-build laboratory chamber for CO2 experiments 开发一个易于建造的二氧化碳实验室

Matéria (Rio de Janeiro) Pub Date : 2023-07-28 DOI: 10.1590/1517-7076-rmat-2023-0078

L. Fortunato, G. A. Parsekian, A. Neves Junior

{"title":"Developing an easy-to-build laboratory chamber for CO2 experiments","authors":"L. Fortunato, G. A. Parsekian, A. Neves Junior","doi":"10.1590/1517-7076-rmat-2023-0078","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0078","url":null,"abstract":"Carbonation chambers, in general, are used in civil engineering laboratories both for verification tests of the useful life of reinforced concrete, and for CO 2 curing tests of unreinforced cementitious materials. These chambers can be purchased from specialized manufacturers at a high cost, or they can be built by the researchers themselves. It so happens that in the literature there is no manual for making and operating an accelerated carbonation chamber. It is observed that its development and manufacture depend a lot on the needs and financial conditions of the research, with no standard or Technical Norm to be followed. This article presents a compilation of concepts related to the accelerated carbonation reaction and brings a bibliographical review about the different carbonation chambers made by researchers, in which it was possible to verify a great variation regarding the material to be used in the structure of the chamber, location of CO 2 and air inlet and outlet valves, temperature and humidity control, among others; and in addition, it presents a descriptive memorial for the construction of an automated and accessible carbonation chamber to be used in laboratories.","PeriodicalId":18246,"journal":{"name":"Matéria (Rio de Janeiro)","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74224186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

ANN- PSO modelling for predicting buckling of self-compacting concrete column containing RHA properties 含RHA自密实混凝土柱屈曲预测的ANN- PSO模型

Matéria (Rio de Janeiro) Pub Date : 2023-07-24 DOI: 10.1590/1517-7076-rmat-2023-0102

A. Jabar, P. T

{"title":"ANN- PSO modelling for predicting buckling of self-compacting concrete column containing RHA properties","authors":"A. Jabar, P. T","doi":"10.1590/1517-7076-rmat-2023-0102","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0102","url":null,"abstract":"In recent decades, concrete technology has reached the broad-based areas of operations through the implementation of Self Compacting Concrete to increase the concrete performance. Due to high silica content, the pozzo-lonic characteristic of RHA makes it as a supplementary material for cement. In this paper, Cement was partially replaced with Rice Hush Ash of 5%, 10% 15%, 20%, 30% and 40% influencing the properties of SCC. The aim of this report is to explore the effect of cement replacement by RHA on the fresh and mechanical properties of SCC. In addition, the bucking behaviour of the axial loaded reinforced concrete column was predicted using Artificial Neural Network. Experimental data are collected and 100 experimental data is used for training the ANN model and 20 sets of data is utilized for testing. From the results it is observed that SCC blended with RHA shows the positive relationship between 30% replacement of RHA with an increase in the strength of compression and tensile strength of around 6. The buckling behaviour of the 70% Cement + 30% RHA SCC reinforced column was predicted by ANN-PSO is a precision and efficient model.","PeriodicalId":18246,"journal":{"name":"Matéria (Rio de Janeiro)","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88394860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0