Roberto souza | Faculdade de Tecnologia senac GO (original) (raw)
Papers by Roberto souza
Surface and Coatings Technology, 2010
In this work, an axisymmetric two-dimensional finite element model was developed to simulate inst... more In this work, an axisymmetric two-dimensional finite element model was developed to simulate instrumented indentation testing of thin ceramic films deposited onto hard steel substrates. The level of film residual stress (σr), the film elastic modulus (E) and the film work hardening exponent (n) were varied to analyze their effects on indentation data. These numerical results were used to analyze
Revista Brasileira de Ciência do Solo, 2005
A sorção de herbicidas no solo é um dos processos determinantes na sua dinâmica no ambiente. Para... more A sorção de herbicidas no solo é um dos processos determinantes na sua dinâmica no ambiente. Para compostos fracamente polares, como é caso do acetochlor, a matéria orgânica do solo constitui o principal sorvente. O objetivo deste estudo foi avaliar a sorção de acetochlor em amostras de solo, de ácidos húmicos e de huminas de um Argissolo Vermelho distrófico (PVd) submetido à semeadura direta e ao preparo convencional. Isotermas de sorção foram obtidas em temperatura ambiente e a concentração do herbicida foi determinada por cromatografia líquida de alta eficiência. As amostras de solo foram caracterizadas pelos teores de C orgânico e de substâncias húmicas; os ácidos húmicos e huminas foram caracterizados por análise elementar. A capacidade de sorção de acetochlor foi superior no solo de semeadura direta (K d = 1,22 ± 0,11 L kg -1 , K OC = 116 ± 10 L kg -1 C) em relação ao preparo convencional (K d = 0,76 ± 0,08 L kg -1 , K OC = 86 ± 8 L kg -1 C). Este comportamento foi relacionado, em parte, com o maior teor de C no solo tratado com semeadura direta. Nos ácidos húmicos de preparo convencional, a sorção (K d = 178 ± 18,9 L kg -1 , K OC = 352 ± 37 L kg -1 C) foi similar à verificada nos ácidos húmicos de semeadura direta (K d = 158 ± 14,6 L kg -1 , K OC = 321 ± 30 L kg -1 C); situação semelhante foi observada com as huminas. Dentre as frações húmicas avaliadas, as huminas apresentaram maior capacidade de sorção (Kd = 1.028 e 1.183 L kg -1 , K OC = 2.691 e 2.892 L kg -1 C).
Surface and Coatings Technology, 2010
In this work, the applicability of a new algorithm for the estimation of mechanical properties fr... more In this work, the applicability of a new algorithm for the estimation of mechanical properties from instrumented indentation data was studied for thin films. The applicability was analyzed with the aid of both three-dimensional finite element simulations and experimental indentation tests. The numerical approach allowed studying the effect of the substrate on the estimation of mechanical properties of the film,
Wear, 2009
Thin hard coatings on components and tools are used increasingly due to the rapid development in ... more Thin hard coatings on components and tools are used increasingly due to the rapid development in deposition techniques, tribological performance and application skills. The residual stresses in a coated surface are crucial for its tribological performance. Compressive residual stresses in PVD deposited TiN and DLC coatings were measured to be in the range of 0.03-4 GPa on steel substrate and 0.1-1.3 GPa on silicon. MoS 2 coatings had tensional stresses in the range of 0.8-1.3 on steel and 0.16 GPa compressive stresses on silicon. The fracture pattern of coatings deposited on steel substrate were analysed both in bend testing and scratch testing. A micro-scale finite element method (FEM) modelling and stress simulation of a 2 m TiN-coated steel surface was carried out and showed a reduction of the generated tensile buckling stresses in front of the sliding tip when compressive residual stresses of 1 GPa were included in the model. However, this reduction is not similarly observed in the scratch groove behind the tip, possibly due to sliding contact-induced stress relaxation. Scratch and bending tests allowed calculation of the fracture toughness of the three coated surfaces, based on both empirical crack pattern observations and FEM stress calculation, which resulted in highest values for TiN coating followed by MoS 2 and DLC coatings, being K C = 4-11, about 2, and 1-2 MPa m 1/2 , respectively. Higher compressive residual stresses in the coating and higher elastic modulus of the coating correlated to increased fracture toughness of the coated surface.
Advances in Experimental Medicine and Biology, 2012
Osteoarthritis and Cartilage, 2013
can be detected in the rat MMT model of knee OA. Moreover, loading changes due to a surgically-si... more can be detected in the rat MMT model of knee OA. Moreover, loading changes due to a surgically-simulated medial meniscus tear could be differentiated from loading changes due to MCL transection alone in the rat MMT model of knee OA.
2012 25th SIBGRAPI Conference on Graphics, Patterns and Images, 2012
. From left to right: synthetic bidimensional dataset, OPF decision boundary, 1-NN decision bound... more . From left to right: synthetic bidimensional dataset, OPF decision boundary, 1-NN decision boundary, 3-NN decision boundary, 5-NN decision boundary, 7-NN decision boundary.
Organometallics, 1998
Palladium(II) compounds dissolved in 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI·BF 4 ) ... more Palladium(II) compounds dissolved in 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI·BF 4 ) ionic liquid are shown to be able to catalyze the hydrodimerization of 1,3-butadiene. In most of the cases, only the 1,3-butadiene dimer 1,3,6-octatriene and the telomer octa-2,7-dien-...
Transactions of the Royal Society of Tropical Medicine and Hygiene, 2010
This study used a PCR-RFLP test to determine the presence of Leishmania (Leishmania) chagasi in 1... more This study used a PCR-RFLP test to determine the presence of Leishmania (Leishmania) chagasi in 16 captive wild felids [seven Puma concolor (Linnaeus, 1771); five Panthera onca (Linnaeus, 1758) and four Leopardus pardalis (Linnaeus, 1758)] at the zoological park of the Federal University of Mato Grosso, Brazil. Amplification of Leishmania spp. DNA was seen in samples from five pumas and one jaguar, and the species was characterized as L. chagasi using restriction enzymes. It is already known that domestic felids can act as a reservoir of L. chagasi in endemic areas, and further studies are necessary to investigate their participation in the epidemiological chain of leishmaniasis.
New Journal of Chemistry, 2002
1,2-Diiminophosphoranes 14 featuring either ethane, benzene, cyclohexane or 1,2-diphenylethane c... more 1,2-Diiminophosphoranes 14 featuring either ethane, benzene, cyclohexane or 1,2-diphenylethane carbon backbones act as tightly bonded 1,4-chelating ligands towards NiCl 2 , affording the corresponding paramagnetic complexes 58 in high yield. X-Ray diffraction studies performed on ...
![Research paper thumbnail of Water-induced accelerated ion diffusion: voltammetric studies in 1-methyl-3-[2,6-(S)-dimethylocten-2-yl]imidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate and hexafluorophosphate ionic liquids](https://attachments.academia-assets.com/43821452/thumbnails/1.jpg)
](New Journal of Chemistry, 2000
Water-induced accelerated ion di †usion : voltammetric studies in 1-methyl-3-[ 2,6-(S)-dimethyloc... more Water-induced accelerated ion di †usion : voltammetric studies in 1-methyl-3-[ 2,6-(S)-dimethylocten-2-yl ] imidazolium tetraÑuoroborate, 1-butyl-3-methylimidazolium tetraÑuoroborate and hexaÑuorophosphate ionic liquids
Microporous and Mesoporous Materials, 2006
... a, Instituto de Quı´mica, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 950... more ... a, Instituto de Quı´mica, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Porto Alegre 91501-970, Brazil. b, Instituto de Quı´mica, Universidade Estadual de Campinas, CP 6154, Campinas 13083-970, Brazil. ...
Key Engineering Materials, 1997
... used to produce rectangular bars (4x3x60mm). Both were compacted in a uniaxialpress at 70MPa ... more ... used to produce rectangular bars (4x3x60mm). Both were compacted in a uniaxialpress at 70MPa and sintered at 1550°C for 2h The ALCOA alumina is a conventional alumina powder. The EPUSP alumina is a experimental ...
Microporous and Mesoporous Materials, 2004
Nickel supported species obtained by impregnation of Ni(acac) 2 onto faujasite zeolite (NaX and N... more Nickel supported species obtained by impregnation of Ni(acac) 2 onto faujasite zeolite (NaX and NaY) were identified by XPS and the influence of the nature of the support has been correlated with the location of the species in/on the zeolite. In the case of NaX two species are formed, one characterized by binding energy of 856.3 eV and ascribed to Ni(acac) 2 interacting with the support and the other with binding energy of 853.4 eV, similar to NiO. In the case of NaY only one species with BE of 854.4 eV is observed and has been ascribed to a nickel complex with one acac and oxygen of the framework of the zeolite as ligands. Ni(acac) 2 interacts differently with NaX and NaY according to the (Si/Al) ratio. Collapse of the NaX zeolite upon impregnation has been identified by textural analysis and related with the presence of more basic oxygen in its structure.
Revista Brasileira de Engenharia Agrícola e Ambiental, 2006
O objetivo deste trabalho foi modelar empiricamente a biodegradação de efluentes protéicos por en... more O objetivo deste trabalho foi modelar empiricamente a biodegradação de efluentes protéicos por enzimas papaínas do látex de Carica papaya sp. num biorreator agitado, para facilitar a otimização do processo por metodologia de análise de superfície de resposta (RSM) e aplicar em tratamento de efluentes provenientes de indústrias de processamento de carne. As análises das curvas de biodegradação mostraram que o tempo de residência para os biorreatores está entre 28 e 30 h. O modelo empírico que mais se ajustou aos dados de biodegradação sob influência dos fatores (pH e temperatura) foi o de um hiperplano e a região de operação otimizada para a degradação de proteínas pelas papaínas foi aquela que apresentou os maiores valores de temperatura e menores valores de pH.
Macromolecules, 1999
... Polym. Sci.1997, 64, 2567−2574. (6) Quijada, R.; Galland, GB; Mauler, RS Macromol. Chem. Phys... more ... Polym. Sci.1997, 64, 2567−2574. (6) Quijada, R.; Galland, GB; Mauler, RS Macromol. Chem. Phys.1996, 197, 3091−3098. ... Eric D. Schwerdtfeger, Craig J. Price, Jianfang Chai and Stephen A. Miller. Macromolecules 2010 43 (11), 4838-4842. ...
Surface and Coatings Technology, 2010
In this work, an axisymmetric two-dimensional finite element model was developed to simulate inst... more In this work, an axisymmetric two-dimensional finite element model was developed to simulate instrumented indentation testing of thin ceramic films deposited onto hard steel substrates. The level of film residual stress (σr), the film elastic modulus (E) and the film work hardening exponent (n) were varied to analyze their effects on indentation data. These numerical results were used to analyze
Revista Brasileira de Ciência do Solo, 2005
A sorção de herbicidas no solo é um dos processos determinantes na sua dinâmica no ambiente. Para... more A sorção de herbicidas no solo é um dos processos determinantes na sua dinâmica no ambiente. Para compostos fracamente polares, como é caso do acetochlor, a matéria orgânica do solo constitui o principal sorvente. O objetivo deste estudo foi avaliar a sorção de acetochlor em amostras de solo, de ácidos húmicos e de huminas de um Argissolo Vermelho distrófico (PVd) submetido à semeadura direta e ao preparo convencional. Isotermas de sorção foram obtidas em temperatura ambiente e a concentração do herbicida foi determinada por cromatografia líquida de alta eficiência. As amostras de solo foram caracterizadas pelos teores de C orgânico e de substâncias húmicas; os ácidos húmicos e huminas foram caracterizados por análise elementar. A capacidade de sorção de acetochlor foi superior no solo de semeadura direta (K d = 1,22 ± 0,11 L kg -1 , K OC = 116 ± 10 L kg -1 C) em relação ao preparo convencional (K d = 0,76 ± 0,08 L kg -1 , K OC = 86 ± 8 L kg -1 C). Este comportamento foi relacionado, em parte, com o maior teor de C no solo tratado com semeadura direta. Nos ácidos húmicos de preparo convencional, a sorção (K d = 178 ± 18,9 L kg -1 , K OC = 352 ± 37 L kg -1 C) foi similar à verificada nos ácidos húmicos de semeadura direta (K d = 158 ± 14,6 L kg -1 , K OC = 321 ± 30 L kg -1 C); situação semelhante foi observada com as huminas. Dentre as frações húmicas avaliadas, as huminas apresentaram maior capacidade de sorção (Kd = 1.028 e 1.183 L kg -1 , K OC = 2.691 e 2.892 L kg -1 C).
Surface and Coatings Technology, 2010
In this work, the applicability of a new algorithm for the estimation of mechanical properties fr... more In this work, the applicability of a new algorithm for the estimation of mechanical properties from instrumented indentation data was studied for thin films. The applicability was analyzed with the aid of both three-dimensional finite element simulations and experimental indentation tests. The numerical approach allowed studying the effect of the substrate on the estimation of mechanical properties of the film,
Wear, 2009
Thin hard coatings on components and tools are used increasingly due to the rapid development in ... more Thin hard coatings on components and tools are used increasingly due to the rapid development in deposition techniques, tribological performance and application skills. The residual stresses in a coated surface are crucial for its tribological performance. Compressive residual stresses in PVD deposited TiN and DLC coatings were measured to be in the range of 0.03-4 GPa on steel substrate and 0.1-1.3 GPa on silicon. MoS 2 coatings had tensional stresses in the range of 0.8-1.3 on steel and 0.16 GPa compressive stresses on silicon. The fracture pattern of coatings deposited on steel substrate were analysed both in bend testing and scratch testing. A micro-scale finite element method (FEM) modelling and stress simulation of a 2 m TiN-coated steel surface was carried out and showed a reduction of the generated tensile buckling stresses in front of the sliding tip when compressive residual stresses of 1 GPa were included in the model. However, this reduction is not similarly observed in the scratch groove behind the tip, possibly due to sliding contact-induced stress relaxation. Scratch and bending tests allowed calculation of the fracture toughness of the three coated surfaces, based on both empirical crack pattern observations and FEM stress calculation, which resulted in highest values for TiN coating followed by MoS 2 and DLC coatings, being K C = 4-11, about 2, and 1-2 MPa m 1/2 , respectively. Higher compressive residual stresses in the coating and higher elastic modulus of the coating correlated to increased fracture toughness of the coated surface.
Advances in Experimental Medicine and Biology, 2012
Osteoarthritis and Cartilage, 2013
can be detected in the rat MMT model of knee OA. Moreover, loading changes due to a surgically-si... more can be detected in the rat MMT model of knee OA. Moreover, loading changes due to a surgically-simulated medial meniscus tear could be differentiated from loading changes due to MCL transection alone in the rat MMT model of knee OA.
2012 25th SIBGRAPI Conference on Graphics, Patterns and Images, 2012
. From left to right: synthetic bidimensional dataset, OPF decision boundary, 1-NN decision bound... more . From left to right: synthetic bidimensional dataset, OPF decision boundary, 1-NN decision boundary, 3-NN decision boundary, 5-NN decision boundary, 7-NN decision boundary.
Organometallics, 1998
Palladium(II) compounds dissolved in 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI·BF 4 ) ... more Palladium(II) compounds dissolved in 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI·BF 4 ) ionic liquid are shown to be able to catalyze the hydrodimerization of 1,3-butadiene. In most of the cases, only the 1,3-butadiene dimer 1,3,6-octatriene and the telomer octa-2,7-dien-...
Transactions of the Royal Society of Tropical Medicine and Hygiene, 2010
This study used a PCR-RFLP test to determine the presence of Leishmania (Leishmania) chagasi in 1... more This study used a PCR-RFLP test to determine the presence of Leishmania (Leishmania) chagasi in 16 captive wild felids [seven Puma concolor (Linnaeus, 1771); five Panthera onca (Linnaeus, 1758) and four Leopardus pardalis (Linnaeus, 1758)] at the zoological park of the Federal University of Mato Grosso, Brazil. Amplification of Leishmania spp. DNA was seen in samples from five pumas and one jaguar, and the species was characterized as L. chagasi using restriction enzymes. It is already known that domestic felids can act as a reservoir of L. chagasi in endemic areas, and further studies are necessary to investigate their participation in the epidemiological chain of leishmaniasis.
New Journal of Chemistry, 2002
1,2-Diiminophosphoranes 14 featuring either ethane, benzene, cyclohexane or 1,2-diphenylethane c... more 1,2-Diiminophosphoranes 14 featuring either ethane, benzene, cyclohexane or 1,2-diphenylethane carbon backbones act as tightly bonded 1,4-chelating ligands towards NiCl 2 , affording the corresponding paramagnetic complexes 58 in high yield. X-Ray diffraction studies performed on ...
New Journal of Chemistry, 2000
Water-induced accelerated ion di †usion : voltammetric studies in 1-methyl-3-[ 2,6-(S)-dimethyloc... more Water-induced accelerated ion di †usion : voltammetric studies in 1-methyl-3-[ 2,6-(S)-dimethylocten-2-yl ] imidazolium tetraÑuoroborate, 1-butyl-3-methylimidazolium tetraÑuoroborate and hexaÑuorophosphate ionic liquids
Microporous and Mesoporous Materials, 2006
... a, Instituto de Quı´mica, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 950... more ... a, Instituto de Quı´mica, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Porto Alegre 91501-970, Brazil. b, Instituto de Quı´mica, Universidade Estadual de Campinas, CP 6154, Campinas 13083-970, Brazil. ...
Key Engineering Materials, 1997
... used to produce rectangular bars (4x3x60mm). Both were compacted in a uniaxialpress at 70MPa ... more ... used to produce rectangular bars (4x3x60mm). Both were compacted in a uniaxialpress at 70MPa and sintered at 1550°C for 2h The ALCOA alumina is a conventional alumina powder. The EPUSP alumina is a experimental ...
Microporous and Mesoporous Materials, 2004
Nickel supported species obtained by impregnation of Ni(acac) 2 onto faujasite zeolite (NaX and N... more Nickel supported species obtained by impregnation of Ni(acac) 2 onto faujasite zeolite (NaX and NaY) were identified by XPS and the influence of the nature of the support has been correlated with the location of the species in/on the zeolite. In the case of NaX two species are formed, one characterized by binding energy of 856.3 eV and ascribed to Ni(acac) 2 interacting with the support and the other with binding energy of 853.4 eV, similar to NiO. In the case of NaY only one species with BE of 854.4 eV is observed and has been ascribed to a nickel complex with one acac and oxygen of the framework of the zeolite as ligands. Ni(acac) 2 interacts differently with NaX and NaY according to the (Si/Al) ratio. Collapse of the NaX zeolite upon impregnation has been identified by textural analysis and related with the presence of more basic oxygen in its structure.
Revista Brasileira de Engenharia Agrícola e Ambiental, 2006
O objetivo deste trabalho foi modelar empiricamente a biodegradação de efluentes protéicos por en... more O objetivo deste trabalho foi modelar empiricamente a biodegradação de efluentes protéicos por enzimas papaínas do látex de Carica papaya sp. num biorreator agitado, para facilitar a otimização do processo por metodologia de análise de superfície de resposta (RSM) e aplicar em tratamento de efluentes provenientes de indústrias de processamento de carne. As análises das curvas de biodegradação mostraram que o tempo de residência para os biorreatores está entre 28 e 30 h. O modelo empírico que mais se ajustou aos dados de biodegradação sob influência dos fatores (pH e temperatura) foi o de um hiperplano e a região de operação otimizada para a degradação de proteínas pelas papaínas foi aquela que apresentou os maiores valores de temperatura e menores valores de pH.
Macromolecules, 1999
... Polym. Sci.1997, 64, 2567−2574. (6) Quijada, R.; Galland, GB; Mauler, RS Macromol. Chem. Phys... more ... Polym. Sci.1997, 64, 2567−2574. (6) Quijada, R.; Galland, GB; Mauler, RS Macromol. Chem. Phys.1996, 197, 3091−3098. ... Eric D. Schwerdtfeger, Craig J. Price, Jianfang Chai and Stephen A. Miller. Macromolecules 2010 43 (11), 4838-4842. ...