Pub Date : 2023-01-01DOI: 10.1590/1517-7076-rmat-2023-0180
Luis Paulo Brasil de Souza, Dario Prada Parra, José Alan Foicinha Raiol, Arthur Martins Barbosa Braga, Leonardo Dantas Rodrigues
The loads acting on mechanical components are usually complex, and the more traditional fatigue analysis criteria may be non-conservative, especially in out-of-phase and non-proportional loadings. Many multiaxial fatigue models have been developed and need to be experimentally validated. This work describes the load control mechanism of a low-cost electromechanical multiaxial fatigue testing machine, which applies variable axial and torsional loads. A load cell interconnected to the motor control system was manufactured and instrumented with extensometers. For the axial load, a four-bar mechanism coupled to a power screw was designed to apply alternating axial loads, thus ensuring a higher load frequency and preservation of the motor, which will not need to alternate its direction of rotation. The machine’s control system, focused on out-phase loading, is based on the data sent by the load cell and pulse encoders per degree for each motor, ensuring good accuracy in applied loads. Tests were carried out to check the system’s response, in which it was possible to apply load curves of torque and axial force in different phase shift angle. Therefore, several existing multiaxial fatigue models can be tested with good reliability.
{"title":"Control of a mechanism for the application of variable axial loads in a multiaxial fatigue testing machine","authors":"Luis Paulo Brasil de Souza, Dario Prada Parra, José Alan Foicinha Raiol, Arthur Martins Barbosa Braga, Leonardo Dantas Rodrigues","doi":"10.1590/1517-7076-rmat-2023-0180","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0180","url":null,"abstract":"The loads acting on mechanical components are usually complex, and the more traditional fatigue analysis criteria may be non-conservative, especially in out-of-phase and non-proportional loadings. Many multiaxial fatigue models have been developed and need to be experimentally validated. This work describes the load control mechanism of a low-cost electromechanical multiaxial fatigue testing machine, which applies variable axial and torsional loads. A load cell interconnected to the motor control system was manufactured and instrumented with extensometers. For the axial load, a four-bar mechanism coupled to a power screw was designed to apply alternating axial loads, thus ensuring a higher load frequency and preservation of the motor, which will not need to alternate its direction of rotation. The machine’s control system, focused on out-phase loading, is based on the data sent by the load cell and pulse encoders per degree for each motor, ensuring good accuracy in applied loads. Tests were carried out to check the system’s response, in which it was possible to apply load curves of torque and axial force in different phase shift angle. Therefore, several existing multiaxial fatigue models can be tested with good reliability.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135502023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1590/1517-7076-rmat-2023-0142
Eliédson Rafael de Carvalho, Áurea Luiza Quixabeira Rosa e Silva Rapôso, Ronny Francisco Marques de Souza, Larissa Bezerra da Silva, Sheyla Karolina Justino Marques
RESUMO Este trabalho teve por objetivo analisar a viabilidade da produção de pisogramas de concreto com a incorporação de fibras de papel kraft provenientes de embalagens de cimento pós-uso. As embalagens foram coletadas e processadas, resultando nas fibras de papel kraft (FPK). Foi adotado o traço de referência de 1:2,31:2,49:0,54 nas proporções de massa de cimento, agregado miúdo, agregado graúdo e fator água/cimento, respectivamente. Estudou-se duas composições com incorporação de FPK nos percentuais de 0,5% e 1,0% em relação à massa total de agregados. Para cada composição, foram moldados 4 corpos de prova e executados os ensaios de absorção de água e resistência à compressão aos 28 dias. Como resultado, todas composições apresentaram absorção de água abaixo do limite normativo de 6%. No ensaio de resistência à compressão, as composições de referência, de 0,5% e de 1,0% de FPK obtiveram 35,55 MPa, 30,61 MPa e 28,40 MPa, respectivamente. Como o concreto com 0,5% de incorporação de FPK obteve melhor desempenho mecânico, foram confeccionados 6 pisogramas para realização da inspeção visual e avaliação dimensional, os quais atenderam aos requisitos normativos. Este trabalho mostra a viabilidade de produção de concreto com FPK e a utilização deste na fabricação de pisogramas para áreas que exijam até 30 MPa.
{"title":"Incorporação de fibras de papel kraft provenientes de embalagens de cimento pós-uso para produção de pisogramas de concreto","authors":"Eliédson Rafael de Carvalho, Áurea Luiza Quixabeira Rosa e Silva Rapôso, Ronny Francisco Marques de Souza, Larissa Bezerra da Silva, Sheyla Karolina Justino Marques","doi":"10.1590/1517-7076-rmat-2023-0142","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0142","url":null,"abstract":"RESUMO Este trabalho teve por objetivo analisar a viabilidade da produção de pisogramas de concreto com a incorporação de fibras de papel kraft provenientes de embalagens de cimento pós-uso. As embalagens foram coletadas e processadas, resultando nas fibras de papel kraft (FPK). Foi adotado o traço de referência de 1:2,31:2,49:0,54 nas proporções de massa de cimento, agregado miúdo, agregado graúdo e fator água/cimento, respectivamente. Estudou-se duas composições com incorporação de FPK nos percentuais de 0,5% e 1,0% em relação à massa total de agregados. Para cada composição, foram moldados 4 corpos de prova e executados os ensaios de absorção de água e resistência à compressão aos 28 dias. Como resultado, todas composições apresentaram absorção de água abaixo do limite normativo de 6%. No ensaio de resistência à compressão, as composições de referência, de 0,5% e de 1,0% de FPK obtiveram 35,55 MPa, 30,61 MPa e 28,40 MPa, respectivamente. Como o concreto com 0,5% de incorporação de FPK obteve melhor desempenho mecânico, foram confeccionados 6 pisogramas para realização da inspeção visual e avaliação dimensional, os quais atenderam aos requisitos normativos. Este trabalho mostra a viabilidade de produção de concreto com FPK e a utilização deste na fabricação de pisogramas para áreas que exijam até 30 MPa.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135101375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1590/1517-7076-rmat-2023-0179
Amalnathan Alex Rajesh, Shanmugamoorthy Senthilkumar, Kandasamy Sargunan, Gobi Nagappan Gobinath
The utilisation of various resources, specifically industrial wastes, in the manufacturing of concrete is the main emphasis of today’s knowledge of concrete technology. One of the key concerns in the global protection of the environment is waste management. The growing growth of the Indian automobile industry has ultimately led to a rise in the garbage that is dumped, such as used tyres. Coal ash was also added to the improvised concrete mix (CRAC) in a frozen percentage within the cement mantle of the concrete matrix for the stabilization of the binding qualities. For sustaining the required qualities of supplied 30 MPa or other base values for concrete with reference to a specific purpose, it was found that an optimal proportional combination of 12% waste rubber tyre crumbs and 9% coal ash was the most technologically and economically effective solution. Flexural strength of 5.18 MPa, which was attained, confirmed that this optimum proportionate combination was the best and most durable.
{"title":"Interpolation and extrapolation of flexural strength of rubber crumbs and coal ash with graphene oxide concrete","authors":"Amalnathan Alex Rajesh, Shanmugamoorthy Senthilkumar, Kandasamy Sargunan, Gobi Nagappan Gobinath","doi":"10.1590/1517-7076-rmat-2023-0179","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0179","url":null,"abstract":"The utilisation of various resources, specifically industrial wastes, in the manufacturing of concrete is the main emphasis of today’s knowledge of concrete technology. One of the key concerns in the global protection of the environment is waste management. The growing growth of the Indian automobile industry has ultimately led to a rise in the garbage that is dumped, such as used tyres. Coal ash was also added to the improvised concrete mix (CRAC) in a frozen percentage within the cement mantle of the concrete matrix for the stabilization of the binding qualities. For sustaining the required qualities of supplied 30 MPa or other base values for concrete with reference to a specific purpose, it was found that an optimal proportional combination of 12% waste rubber tyre crumbs and 9% coal ash was the most technologically and economically effective solution. Flexural strength of 5.18 MPa, which was attained, confirmed that this optimum proportionate combination was the best and most durable.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136305983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1590/1517-7076-rmat-2023-0225
Wentao Su, Weijun Meng, Xingyuan Chen
The annual output of refinery waste sludge is huge in our country, and the resource disposal of sludge has become a difficult problem that needs to be overcome. In order to increase the content of renewable gas and light oil after pyrolysis of oil sludge at the bottom of refinery tank, nano-CuO and nano-γ-Al2O3 with good wave-absorbing property and good catalytic property were selected to study the effect of additive load on the characteristics of pyrolysis reaction products by experimental research and analysis. The results show that the highest oil and gas yields can be obtained when the nano-CuO content is 10%. When nano-γ-Al2O3 was loaded at 15%, the pyrolysis oil and pyrolysis gas yield reached the peak. Moreover, the light component of pyrolysis oil can be improved, and the proportion of gasoline and diesel (C4 ~ C12, C13 ~ C18) is 75.422%. H2 volume content reaches the highest at 15% load.
{"title":"The impact of nano-additives on the properties of sludge microwave pyrolysis products","authors":"Wentao Su, Weijun Meng, Xingyuan Chen","doi":"10.1590/1517-7076-rmat-2023-0225","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0225","url":null,"abstract":"The annual output of refinery waste sludge is huge in our country, and the resource disposal of sludge has become a difficult problem that needs to be overcome. In order to increase the content of renewable gas and light oil after pyrolysis of oil sludge at the bottom of refinery tank, nano-CuO and nano-γ-Al2O3 with good wave-absorbing property and good catalytic property were selected to study the effect of additive load on the characteristics of pyrolysis reaction products by experimental research and analysis. The results show that the highest oil and gas yields can be obtained when the nano-CuO content is 10%. When nano-γ-Al2O3 was loaded at 15%, the pyrolysis oil and pyrolysis gas yield reached the peak. Moreover, the light component of pyrolysis oil can be improved, and the proportion of gasoline and diesel (C4 ~ C12, C13 ~ C18) is 75.422%. H2 volume content reaches the highest at 15% load.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135214458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the rapid urbanisation and rapid population explosion, there is a vast essential requirement in the dispose of solid waste. Carbonization of Styrofoam is carried out at varying temperature ranges of 300°C to 675°C at an interval of 75°C using KOH as reagent. The Characterisation of power of hydrogen ion, ash and moisture content, fixed carbon, Volatile matter, iodine adsorption value, methyl blue value was conducted. It was found that the activate carbon obtain from the temperature of 525°C has a good carbon characteristic. The batch experiment such has pH, contact time, carbon dosage, agitation speed, potency of Nickel (II) was conducted with the purpose of ascertaining the efficiency of Nickel (II) adsorption. This analysis deals with fixed bed column to remove Nickel (II) from a solution. The results indicated that the sorption-second order kinetic model was the most appropriate fit for the data, and alternative models such as Adams-Bhorat, Thomas, and Yoon Nelson’s were also evaluated. Increasing a bed height resulted in better removal of Nickel (II) in all 3 models. Therefore, The utilization of Styrofoam-derived activated carbon as a medium for ongoing Nickel (II) adsorption from an aqueous solution.
{"title":"Synthesized activated carbon derived from discarded styrofoam and effectively removal of nickel (II) from aqueous solutions","authors":"Roopa Dakshinamurthy, Balasundaram Natarajan, Meiaraj Chelladurai","doi":"10.1590/1517-7076-rmat-2023-0195","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0195","url":null,"abstract":"Due to the rapid urbanisation and rapid population explosion, there is a vast essential requirement in the dispose of solid waste. Carbonization of Styrofoam is carried out at varying temperature ranges of 300°C to 675°C at an interval of 75°C using KOH as reagent. The Characterisation of power of hydrogen ion, ash and moisture content, fixed carbon, Volatile matter, iodine adsorption value, methyl blue value was conducted. It was found that the activate carbon obtain from the temperature of 525°C has a good carbon characteristic. The batch experiment such has pH, contact time, carbon dosage, agitation speed, potency of Nickel (II) was conducted with the purpose of ascertaining the efficiency of Nickel (II) adsorption. This analysis deals with fixed bed column to remove Nickel (II) from a solution. The results indicated that the sorption-second order kinetic model was the most appropriate fit for the data, and alternative models such as Adams-Bhorat, Thomas, and Yoon Nelson’s were also evaluated. Increasing a bed height resulted in better removal of Nickel (II) in all 3 models. Therefore, The utilization of Styrofoam-derived activated carbon as a medium for ongoing Nickel (II) adsorption from an aqueous solution.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135104191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigated the effects of electrokinetic treatments on mortar specimens using a range of experimental techniques. Ionic migration tests revealed that increasing voltage and duration led to higher charge transfer, with Ca(OH)2 electrolyte showing the highest cationic migration. X-ray fluorescence analysis indicated that Nano-Silica treatment resulted in the highest oxide content, transforming absorbed elements effectively. The chloride penetration test demonstrated that Ca(OH)2 treatment exhibited the lowest charge passed, suggesting minimal chloride penetration, while NaOH and KOH treatments showed higher charge passed. Field Emission Scanning Electron Microscopy analysis provided visual evidence of structural changes and material depositions. Calcium Hydroxide treatment reduced porosity, Sodium Hydroxide, and Potassium Hydroxide treatments displayed distinct particle distributions, and Nano Silica treatment led to the formation of hair-like crystal structures. These findings help to understand the microstructure and composition of cement mortar specimens after various treatments. The nano-silica electrolyte appeared as a viable choice for electro-kinetic therapy, whereas Ca(OH)2 treatment stated the potential to reduce chloride penetration in mortar specimens. The results offer insights into optimizing electrokinetic treatments for improved mortar performance.
{"title":"Optimizing electrokinetic treatments for enhanced mortar durability: ionic migration and microstructural analysis","authors":"Priyanka Rajendran, Revathi Vaiyapuri, Rajaiah Selvaraj","doi":"10.1590/1517-7076-rmat-2023-0210","DOIUrl":"https://doi.org/10.1590/1517-7076-rmat-2023-0210","url":null,"abstract":"This study investigated the effects of electrokinetic treatments on mortar specimens using a range of experimental techniques. Ionic migration tests revealed that increasing voltage and duration led to higher charge transfer, with Ca(OH)2 electrolyte showing the highest cationic migration. X-ray fluorescence analysis indicated that Nano-Silica treatment resulted in the highest oxide content, transforming absorbed elements effectively. The chloride penetration test demonstrated that Ca(OH)2 treatment exhibited the lowest charge passed, suggesting minimal chloride penetration, while NaOH and KOH treatments showed higher charge passed. Field Emission Scanning Electron Microscopy analysis provided visual evidence of structural changes and material depositions. Calcium Hydroxide treatment reduced porosity, Sodium Hydroxide, and Potassium Hydroxide treatments displayed distinct particle distributions, and Nano Silica treatment led to the formation of hair-like crystal structures. These findings help to understand the microstructure and composition of cement mortar specimens after various treatments. The nano-silica electrolyte appeared as a viable choice for electro-kinetic therapy, whereas Ca(OH)2 treatment stated the potential to reduce chloride penetration in mortar specimens. The results offer insights into optimizing electrokinetic treatments for improved mortar performance.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135106989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-04DOI: 10.1590/S1517-707620210002.1295
Fabiano da Silva Dias, Tayra R. Brazil, Larissa Stieven Montagna, M. C. Rezende
O carbono vitreo reticulado (CVR) e um material carbonoso, rico em atomos de carbono ligados por ligacoes sp2, obtido pelo tratamento termico (TT) de carbonizacao (a pelo menos 1000 oC, sob atmosfera inerte) de resinas termorrigidas. A sua obtencao pode se dar por diferentes metodologias, usualmente pelo uso de um material de sacrificio, que se degrada durante o TT e gera poros de transporte. Este trabalho teve como objetivo avaliar a influencia de diferentes tempos de patamar (2, 8, 12, 24 e 36 h) a 1000 oC nas caracteristicas estruturais, morfologicas e condutividade eletrica de amostras de CVR obtidas a partir de uma espuma de poliuretano (PU, material de sacrificio), impregnada com resina furfurilica (PFA). A espuma de PU/PFA foi caracterizada por espectrofotometria de infravermelho com transformada de Fourier (FT-IR) e analises termogravimetricas, as amostras de CVR por difracao de raios X (DRX), microscopias optica (MO) e eletronica de varredura (MEV), e condutividade eletrica por 2 pontas. Os resultados de FT-IR e DRX confirmam a conversao da espuma de PU/PFA no CVR, com um rendimento de ~44%. As analises de DRX tambem evidenciam mudancas no ordenamento estrutural das amostras de CVR em funcao dos diferentes tempos de patamar, devido a provavel expulsao de heteroatomos ainda presentes na estrutura do referido material carbonoso. As medidas de condutividade eletrica corroboram com essa observacao, com um aumento significativo a partir de 8 h de patamar (de 1,71 x 10-1 para 1,17 x 104 S.cm-1), como uma consequencia da diminuicao de defeitos na estrutura do CVR. As micrografias mostram a estrutura alveolar da espuma de PU/PFA, rica em poros de transporte, que e preservada no CVR, apos a carbonizacao. Palavras-chave: Espuma polimerica. Carbono vitreo reticulado. Tratamento termico. Resina furfurilica.
交联玻璃碳(CVR)是一种碳质材料，富含sp2配体结合的碳原子，通过热处理(TT)碳化(在惰性气氛下至少1000℃)得到热固性树脂。它可以通过不同的方法获得，通常是使用牺牲材料，在TT过程中降解并产生运输孔隙。这个任务的目的是评估不同时期高原的影响(2)8、12、24和36小时)1000度以上的结构性特征,得到了最终的形态和样本的电子导电率从一个泡沫聚氨酯(PU材料牺牲)和树脂浸渍furfurilica (PFA)。采用傅里叶变换红外分光光度法(FT-IR)和热重分析对PU/PFA泡沫进行了表征，采用X射线衍射(xrd)、光学显微镜(om)和扫描电子显微镜(sem)对CVR样品进行了表征，并通过两个点对其电导率进行了表征。FT-IR和xrd结果证实了PU/PFA泡沫转化为CVR，收率为44%。xrd分析还表明，CVR样品的结构顺序在不同的水平时间下发生了变化，这是由于在碳材料的结构中可能仍然存在异质原子的排出。电导率测量证实了这一观察结果，从8小时的水平(从1.71 x 10-1到1.17 x 104 S.cm-1)显著增加，这是CVR结构缺陷减少的结果。显微照片显示PU/PFA泡沫的肺泡结构，富含运输孔，炭化后保存在CVR中。关键词:聚合物泡沫。交联玻璃碳。termico治疗。furfurilica树脂。
{"title":"Estudo da influência dos parâmetros de tratamento térmico da resina furfurílica nas características morfológicas, estruturais e condutividade elétrica do carbono vítreo reticulado","authors":"Fabiano da Silva Dias, Tayra R. Brazil, Larissa Stieven Montagna, M. C. Rezende","doi":"10.1590/S1517-707620210002.1295","DOIUrl":"https://doi.org/10.1590/S1517-707620210002.1295","url":null,"abstract":"O carbono vitreo reticulado (CVR) e um material carbonoso, rico em atomos de carbono ligados por ligacoes sp2, obtido pelo tratamento termico (TT) de carbonizacao (a pelo menos 1000 oC, sob atmosfera inerte) de resinas termorrigidas. A sua obtencao pode se dar por diferentes metodologias, usualmente pelo uso de um material de sacrificio, que se degrada durante o TT e gera poros de transporte. Este trabalho teve como objetivo avaliar a influencia de diferentes tempos de patamar (2, 8, 12, 24 e 36 h) a 1000 oC nas caracteristicas estruturais, morfologicas e condutividade eletrica de amostras de CVR obtidas a partir de uma espuma de poliuretano (PU, material de sacrificio), impregnada com resina furfurilica (PFA). A espuma de PU/PFA foi caracterizada por espectrofotometria de infravermelho com transformada de Fourier (FT-IR) e analises termogravimetricas, as amostras de CVR por difracao de raios X (DRX), microscopias optica (MO) e eletronica de varredura (MEV), e condutividade eletrica por 2 pontas. Os resultados de FT-IR e DRX confirmam a conversao da espuma de PU/PFA no CVR, com um rendimento de ~44%. As analises de DRX tambem evidenciam mudancas no ordenamento estrutural das amostras de CVR em funcao dos diferentes tempos de patamar, devido a provavel expulsao de heteroatomos ainda presentes na estrutura do referido material carbonoso. As medidas de condutividade eletrica corroboram com essa observacao, com um aumento significativo a partir de 8 h de patamar (de 1,71 x 10-1 para 1,17 x 104 S.cm-1), como uma consequencia da diminuicao de defeitos na estrutura do CVR. As micrografias mostram a estrutura alveolar da espuma de PU/PFA, rica em poros de transporte, que e preservada no CVR, apos a carbonizacao. Palavras-chave: Espuma polimerica. Carbono vitreo reticulado. Tratamento termico. Resina furfurilica.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2021-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80842510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-04DOI: 10.1590/S1517-707620210002.1293
J. A. Martinez, Miguel Sanchez Junior, Augusto Nobre Golçalves, R. Orrego, O. Florêncio
Three different processes for the synthetization of exfoliated graphite intercalation compound have been tested in two different type of graphite, one in powder form and the other one as flakes. Each graphite was oxidized applying the same experimental conditions (sonification, neutralization, filtering and drying) but using three different auxiliary oxidizers (H2O2, HNO3 and KClO3) previously mixed with H2SO4. The resulting synthesized samples were characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The Raman spectra analysis of the oxidized samples correspond to that of a graphene of few layers. Stronger delamination and exfoliation were observed in the samples of graphite, originally in powder form, treated with H2SO4/HNO3. Keywords: graphite, graphene, Raman spectroscopy, intercalation.
{"title":"Influence of different oxidation mechanisms on the exfoliation of intercalated graphite bisulfate using two types of graphite","authors":"J. A. Martinez, Miguel Sanchez Junior, Augusto Nobre Golçalves, R. Orrego, O. Florêncio","doi":"10.1590/S1517-707620210002.1293","DOIUrl":"https://doi.org/10.1590/S1517-707620210002.1293","url":null,"abstract":"Three different processes for the synthetization of exfoliated graphite intercalation compound have been tested in two different type of graphite, one in powder form and the other one as flakes. Each graphite was oxidized applying the same experimental conditions (sonification, neutralization, filtering and drying) but using three different auxiliary oxidizers (H2O2, HNO3 and KClO3) previously mixed with H2SO4. The resulting synthesized samples were characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The Raman spectra analysis of the oxidized samples correspond to that of a graphene of few layers. Stronger delamination and exfoliation were observed in the samples of graphite, originally in powder form, treated with H2SO4/HNO3. Keywords: graphite, graphene, Raman spectroscopy, intercalation.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2021-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82241283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-04DOI: 10.1590/S1517-707620210002.1262
Caroline Varella Rodrigues, Luan Vieira Adames, Rodrigo Fernando Costa Marques, Ana Paula Jacobus, Lorena Oliveira Pires, S. I. Maintinguer
A producao de biodiesel tem crescido e ganhado destaque no cenario energetico mundial. Com isso, seu principal coproduto, o glicerol bruto (GB), tem acompanhado esse aumento, ocasionando a formacao de grandes estoques deste residuo. Uma alternativa promissora para a sua reducao consiste na utilizacao por processos biologicos anaerobios visando a producao de biogas, tanto hidrogenio (H2) quanto metano (CH4). Sabe-se que a eficiencia dessa bioconversao aumenta por meio da codigestao com outros residuos orgânicos. Assim, o objetivo deste estudo consistiu na codigestao do GB, proveniente da producao de biodiesel a partir de oleos residuais domesticos, com vinhaca citricola (VC), em dois estagios sequenciais. No 1o estagio (Ensaio 1), o reator anaerobio foi operado em batelada, alimentado com 5 g DQO L-1 GB e 5 g DQO L-1 VC, na presenca de cultura mista pertencente ao genero Clostridium sp., a 37 °C, pH 5,5, headspace com N2, gerando 4,48 mmol H2 L-1 em 112 h de experimento, sendo consumidos 93,19 % de GB e 74,00 % de glicose. Um ensaio controle (Controle 1) foi montado com apenas 5 g DQO L-1 GB, nao sendo verificada producao de H2. O efluente gerado no Ensaio 1 (200 mL) foi usado como substrato no 2o estagio (Ensaio 2) por um inoculo in natura identificado por consorcio de bacterias anaerobias fermentativas e archaeas metanogenicas, no reator anaerobio metanogenico (500 mL), headspace com N2, pH 7,0, a 37 °C, gerando 229,08 mmol CH4 L-1 em 624 h de operacao. Alem disso, 87,34 % da DQO e 93,75 % do metanol proveniente do GB foram consumidos. O efluente gerado pelo Controle 1 produziu apenas 40,58 mmol CH4 L-1 (Controle 2). Dessa forma, constatou-se que a codigestao elevou a geracao de biogas, com consumos de residuos orgânicos e toxicos presentes no GB por meio dos sistemas integrados. Palavras-chave: Biodiesel. Digestao anaerobia. Hidrogenio. Metano.
生物柴油的生产已经增长，并在世界能源格局中获得了突出地位。因此，它的主要副产物粗甘油(GB)也随之增加，导致了这种残留物的大量积累。一种很有前途的还原方法是通过厌氧生物过程产生沼气，包括氢(H2)和甲烷(CH4)。众所周知，这种生物转化的效率是通过与其他有机废物共消化而提高的。因此，本研究的目的是在两个连续的阶段共消化从生活废油生产生物柴油的GB。1(1)测试阶段,反应器anaerobio批量做的手术,受5 g鳕鱼L 1 GB 5 g和鳕鱼,在存在的混合培养的是什么样的sp。梭状芽胞杆菌、37°C, pH值五,五,顶空气和氮气,位列4 L H2中毒1在112小时的实验中,被吃掉了93 GB的19%和74年00%的葡萄糖。对照试验(对照1)仅用5 g cod L-1 GB进行，未验证H2的产生。产生的废水在测试1(200毫升)被用来作为介质在两(2)的一个测试阶段inoculo材料已经由财团的细菌anaerobias fermentativas和古生菌metanogenicas反应堆anaerobio metanogenico (500 mL),顶空气和氮气,pH值7 0,那37°C,位列229年中毒CH4 L 1 624小时的操作。此外，消耗了87.34%的cod和93.75%的GB甲醇。控制1产生的废水仅产生40.58 mmol CH4 L-1(控制2)，因此，通过综合系统，共消化增加了沼气的产生，消耗了GB中存在的有机和有毒废物。关键词:生物柴油。消化anaerobia。成形。甲烷。
{"title":"Biossistemas integrados na codigestão do glicerol bruto em resíduos agroindustriais para a geração de H2 e CH4","authors":"Caroline Varella Rodrigues, Luan Vieira Adames, Rodrigo Fernando Costa Marques, Ana Paula Jacobus, Lorena Oliveira Pires, S. I. Maintinguer","doi":"10.1590/S1517-707620210002.1262","DOIUrl":"https://doi.org/10.1590/S1517-707620210002.1262","url":null,"abstract":"A producao de biodiesel tem crescido e ganhado destaque no cenario energetico mundial. Com isso, seu principal coproduto, o glicerol bruto (GB), tem acompanhado esse aumento, ocasionando a formacao de grandes estoques deste residuo. Uma alternativa promissora para a sua reducao consiste na utilizacao por processos biologicos anaerobios visando a producao de biogas, tanto hidrogenio (H2) quanto metano (CH4). Sabe-se que a eficiencia dessa bioconversao aumenta por meio da codigestao com outros residuos orgânicos. Assim, o objetivo deste estudo consistiu na codigestao do GB, proveniente da producao de biodiesel a partir de oleos residuais domesticos, com vinhaca citricola (VC), em dois estagios sequenciais. No 1o estagio (Ensaio 1), o reator anaerobio foi operado em batelada, alimentado com 5 g DQO L-1 GB e 5 g DQO L-1 VC, na presenca de cultura mista pertencente ao genero Clostridium sp., a 37 °C, pH 5,5, headspace com N2, gerando 4,48 mmol H2 L-1 em 112 h de experimento, sendo consumidos 93,19 % de GB e 74,00 % de glicose. Um ensaio controle (Controle 1) foi montado com apenas 5 g DQO L-1 GB, nao sendo verificada producao de H2. O efluente gerado no Ensaio 1 (200 mL) foi usado como substrato no 2o estagio (Ensaio 2) por um inoculo in natura identificado por consorcio de bacterias anaerobias fermentativas e archaeas metanogenicas, no reator anaerobio metanogenico (500 mL), headspace com N2, pH 7,0, a 37 °C, gerando 229,08 mmol CH4 L-1 em 624 h de operacao. Alem disso, 87,34 % da DQO e 93,75 % do metanol proveniente do GB foram consumidos. O efluente gerado pelo Controle 1 produziu apenas 40,58 mmol CH4 L-1 (Controle 2). Dessa forma, constatou-se que a codigestao elevou a geracao de biogas, com consumos de residuos orgânicos e toxicos presentes no GB por meio dos sistemas integrados. Palavras-chave: Biodiesel. Digestao anaerobia. Hidrogenio. Metano.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2021-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90571019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-04DOI: 10.1590/S1517-707620210002.1296
Sarah Lima, Luis Fernando T. Domingos, Roberto Vaz, Paulo Henrique de Almeida Campos Junior, M. Schiavon
Entre os nanomateriais de carbono, os pontos de carbono (PCs) estao entre os mais atraentes devido as suas interessantes propriedades fotoluminescentes. Os PCs apresentam processo de sintese facil, possibilidade de funcionalizacao da superficie, baixa toxicidade, alta solubilidade em agua e biocompatibilidade. Devido a isso, suas aplicacoes na area biomedica e de bioimagem tem se destacado na literatura. Neste trabalho, PCs foram sintetizados por dois metodos diferentes a partir da ovalbumina, o qual e um precursor nao toxico e composto predominantemente por aminoacidos de cadeia curta. Os PCs foram caracterizados por espectroscopias de absorcao (UV-Vis), de emissao (fluorescencia) e infravermelho (IVTF), alem de analise termogravimetrica (ATG). Os PCs foram utilizados como sondas fluorescentes para uma imagem colorida (azul e verde) de celulas HEK293 e nao induziram a morte celular, o que indica que os mesmos sao biocompativeis e nao toxicos para este tipo de celulas. Dessa forma, os resultados aqui apresentados demonstram que os PCs podem ser considerados potenciais substitutos para corantes comerciais em marcacao biologica. Palavras-chave: nanoparticulas de carbono, fotoluminescencia, biocompatibilidade, HEK293.
{"title":"Pontos de carbono luminescentes à base de ovalbumina aplicados em marcação biológica","authors":"Sarah Lima, Luis Fernando T. Domingos, Roberto Vaz, Paulo Henrique de Almeida Campos Junior, M. Schiavon","doi":"10.1590/S1517-707620210002.1296","DOIUrl":"https://doi.org/10.1590/S1517-707620210002.1296","url":null,"abstract":"Entre os nanomateriais de carbono, os pontos de carbono (PCs) estao entre os mais atraentes devido as suas interessantes propriedades fotoluminescentes. Os PCs apresentam processo de sintese facil, possibilidade de funcionalizacao da superficie, baixa toxicidade, alta solubilidade em agua e biocompatibilidade. Devido a isso, suas aplicacoes na area biomedica e de bioimagem tem se destacado na literatura. Neste trabalho, PCs foram sintetizados por dois metodos diferentes a partir da ovalbumina, o qual e um precursor nao toxico e composto predominantemente por aminoacidos de cadeia curta. Os PCs foram caracterizados por espectroscopias de absorcao (UV-Vis), de emissao (fluorescencia) e infravermelho (IVTF), alem de analise termogravimetrica (ATG). Os PCs foram utilizados como sondas fluorescentes para uma imagem colorida (azul e verde) de celulas HEK293 e nao induziram a morte celular, o que indica que os mesmos sao biocompativeis e nao toxicos para este tipo de celulas. Dessa forma, os resultados aqui apresentados demonstram que os PCs podem ser considerados potenciais substitutos para corantes comerciais em marcacao biologica. Palavras-chave: nanoparticulas de carbono, fotoluminescencia, biocompatibilidade, HEK293.","PeriodicalId":18260,"journal":{"name":"Materia-rio De Janeiro","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2021-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83131446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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