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@MastersThesis{FlˇrezVergara:2019:12BaX,
               author = "Fl{\'o}rez Vergara, Diego Ediss{\'o}n",
                title = "Espumas de carbono de origem sustentav{\'e}l como material 
                         absorvedor de radia{\c{c}}{\~a}o eletromagn{\'e}tica na faixa 
                         de micro-ondas 8,2 - 12,4 (banda X)",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2019",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2019-05-29",
             keywords = "Absorvedor de radia{\c{c}}{\~a}o eletromagn{\'e}tica, espumas 
                         de carbono, carbono poroso, material comp{\'o}sito, 
                         sustentabilidade, electromagnetic radiation absorber, frequency 
                         selective surfaces, carbon foam, composite material, 
                         sustainability.",
             abstract = "Este trabalho descreve a s{\'{\i}}ntese e 
                         caracteriza{\c{c}}{\~a}o de espumas de carbono de natureza 
                         renov{\'a}vel e sua aplicabilidade no setor aeroespacial na 
                         redu{\c{c}}{\~a}o da se{\c{c}}{\~a}o transversal do radar 
                         (Radar Cross Section Reduction - RCSR) atrav{\'e}s da seu uso 
                         como; (i) material absorvedor de radia{\c{c}}{\~a}o 
                         eletromagn{\'e}tica (MARE) e (ii) superf{\'{\i}}cies seletoras 
                         de frequ{\^e}ncia (Frequency Selective Surface - FSS). Na 
                         atualidade, devido ao avan{\c{c}}o da eletr{\^o}nica moderna e 
                         dos circuitos integrados, os MAREs t{\^e}m encontrado uma 
                         expans{\~a}o gradual em outros setores al{\'e}m do 
                         aeron{\'a}utico e aeroespacial, tais como; nas 
                         telecomunica{\c{c}}{\~o}es, na computa{\c{c}}{\~a}o, 
                         automa{\c{c}}{\~a}o e medicina, onde a demanda por estes 
                         materiais tem aumentado consideravelmente com o objetivo de 
                         proteger os sistemas e dispositivos envolvidos de 
                         interfer{\^e}ncias eletromagn{\'e}ticas que possam comprometer o 
                         seu funcionamento e/ou desempenho. O material desenvolvido neste 
                         trabalho foi submetido a um processo de s{\'{\i}}ntese realizado 
                         atrav{\'e}s da mistura do licor negro como precursor principal 
                         junto a precursores secund{\'a}rios que auxiliam no seu processo 
                         de cura e predeterminam algumas propriedades finais do material. 
                         Em seguida, {\'e} realizado um processo de pir{\'o}lise para a 
                         obten{\c{c}}{\~a}o de um material final altamente rico em 
                         carbono, para um posterior processo de caracteriza{\c{c}}{\~a}o 
                         do material, tendo por objetivo descrever a sua estrutura, 
                         composi{\c{c}}{\~a}o, morfologia e propriedades 
                         eletromagn{\'e}ticas na faixa de frequ{\^e}ncia de 8,2 {\`a} 
                         12,4 GHz. No entanto, para a obten{\c{c}}{\~a}o das propriedades 
                         eletromagn{\'e}ticas do material, {\'e} necess{\'a}rio a 
                         produ{\c{c}}{\~a}o de materiais comp{\'o}sitos que s{\~a}o 
                         feitos misturando o material carbonoso com matrizes estruturais de 
                         borracha de silicone ou resina ep{\'o}xi, cujos formatos 
                         geom{\'e}tricos s{\~a}o definidos pelo equipamento 
                         respons{\'a}vel da analise, neste caso, o analisador vetorial de 
                         redes VNA (N5230C PNA-L) com kit de calibra{\c{c}}{\~a}o WR90 
                         X11644A. Assim, avaliou-se o potencial do material na 
                         redu{\c{c}}{\~a}o da se{\c{c}}{\~a}o transversal do radar 
                         atrav{\'e}s de: (I) tipo e concentra{\c{c}}{\~a}o do material 
                         carbonoso; (II) porosidade; (III) geometria superficial; (IV) 
                         matriz estrutural e; (V) espessura dos materiais comp{\'o}sitos. 
                         Pode se concluir assim que para o carbono poroso em matriz 
                         estrutural de borracha de silicone obtiveram-se como resultados 
                         mais significativos aqueles referentes {\`a}s amostras com 
                         maiores concentra{\c{c}}{\~o}es de carbono (20%), espessura de 2 
                         mm e porosidade de 300 \μm < °3 < 420 \μm, conseguindo 
                         uma absor{\c{c}}{\~a}o da energia eletromagn{\'e}tica incidente 
                         de -33,34 dB em 9,87 GHz. Para o carbono poroso com matriz 
                         estrutural de resina ep{\'o}xy, a absor{\c{c}}{\~a}o mais 
                         significativa foi obtida para as amostras com maiores 
                         concentra{\c{c}}{\~o}es de carbono (15%), espessura de 2 mm, 
                         porosidade de 180 \μm < °3 < 250 \μm, tamanho de 
                         part{\'{\i}}cula de 250 < °2 < 425 e sem 
                         transforma{\c{c}}{\~a}o para superf{\'{\i}}cies seletoras de 
                         frequ{\^e}ncia, conseguindo uma absor{\c{c}}{\~a}o de -18,86 dB 
                         em 11,79 GHz. Finalmente, para o carbono+MnSO4.H2O com matriz 
                         estrutural de resina ep{\'o}xy, a absor{\c{c}}{\~a}o mais 
                         significativa foi obtida para as amostras com maiores 
                         concentra{\c{c}}{\~o}es de carbono (20%), espessura de 2 mm e 
                         tamanho de part{\'{\i}}cula de '3 > 63 \μm, conseguindo 
                         uma absor{\c{c}}{\~a}o de -18,37 dB em 8,40 GHz. ABSTRACT: This 
                         research worked on the synthesis and characterization of carbon 
                         foams from renewable nature, and their applicability in the 
                         aerospace sector as radar crosssection reduction (RCSR) through 
                         techniques such as; (i) radar absorbing material (RAM) and (ii) 
                         frequency selective surfaces (FSS). Due to the advance of modern 
                         electronics and integrated circuits, RAMs have found a gradual 
                         expansion in other sectors besides aeronautical and aerospace; 
                         such as, telecommunications, computing, automation, and medicine, 
                         where the demand for these materials has increased considerably in 
                         order to protect the systems and devices involved from 
                         electromagnetic interference that could compromise their operation 
                         and/or performance. To predetermine the final properties of the 
                         material that was being studied, It was subjected to a synthesis 
                         process performed by mixing the black liquor as the main precursor 
                         together with secondary precursors that aid in its curing process. 
                         Next, a pyrolysis process was carried out to obtain a material 
                         highly rich in carbon, for a later process of characterization of 
                         the material, having as an objective the description of its 
                         structure, composition, morphology and electromagnetic properties 
                         (in the frequency range of 8.2 to 12.4 GHz). To obtain the 
                         electromagnetic properties of the material, it was necessary to 
                         produce composite materials that were made by mixing the 
                         carbonaceous material with structural matrices of silicone rubber 
                         or epoxy resin, whose geometric shapes were defined by the 
                         responsible equipment for the electromagnetic analysis; in this 
                         case, a network vector analyzer (VNA N5230C PNA-L) with the 
                         calibration kit WR90 X11644A. Thus, the potential of the material 
                         for the RCSR was evaluated through; (I) type and concentration of 
                         the carbonaceous material, (II) porosity, (III) surface geometry, 
                         (IV) structural matrix and, (V) thickness of the composite 
                         materials. Therefore, can be concluded that for porous carbon in 
                         silicon rubber structural matrix, the most significant results 
                         were obtained for the samples with the highest concentrations of 
                         carbon (20%), thickness of 2 mm and porosity of 300 \μm < °3 
                         < 420 \μm, with an incident electromagnetic energy 
                         absorption of -33.34 dB at 9.87 GHz. For the porous carbon with 
                         the epoxy resin structural matrix, the most significant absorption 
                         was obtained for the samples with higher carbon concentrations 
                         (15%), thickness of 2 mm, porosity of 180 \μm < °3 < 250 
                         \μm, particle size of 250 < °2 < 425 and without 
                         transformation to frequency selective surfaces, achieving an 
                         absorption of -18.86 dB at 11.79 GHz. Finally, for 
                         carbono+MnSO4.H2O with an epoxy resin structural matrix, the most 
                         significant absorption was obtained for the samples with the 
                         highest carbon concentrations (20%) and thickness of 2 mm and 
                         particle size of '3 > 63 \μm, achieving an absorption of 
                         -18.37 dB at 8.40 GHz.",
            committee = "Baldan, Maur{\'{\i}}cio Ribeiro (presidente/orientador) and 
                         Labat, Gisele Aparecida Amaral (orientadora) and Mineiro, Sergio 
                         Luiz and Quirino, Sandro Fonseca and Boss, Alan Fernando Ney",
         englishtitle = "Carbon foams of sustainable origin as electromagnetic radiation 
                         absorbing material in the 8.2 -12.4 GHz microwave range (X Band)",
             language = "pt",
                pages = "137",
                  ibi = "8JMKD3MGP3W34R/3TBGFMH",
                  url = "http://urlib.net/rep/8JMKD3MGP3W34R/3TBGFMH",
           targetfile = "publicacao.pdf",
        urlaccessdate = "27 nov. 2020"
}


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