Nelson Silva - Academia.edu (original) (raw)
Drafts by Nelson Silva
Papers by Nelson Silva
Investigaciones Marinas, 2007
A study of the ecotoxicological quality of surface sediment was carried out on samples collected ... more A study of the ecotoxicological quality of surface sediment was carried out on samples collected in the main fjords and interior channels between Reloncaví and Corcovado gulfs. The surface sediment samples were taken with a box corer and analyzed for organic matter content and grain size. Dissolved oxygen was measured in water samples taken 10 m off the bottom. The ecotoxicological evaluation of the sediments was performed using fertilization assays with gametes of Arbacia spatuligera (EPA/600/4-91/003). A fertilization rate of 95%, similar to that of the controls, was achieved. Therefore, the sediments at the sampled stations located in the middle of the channels were classified as nontoxic. Only the sediment at Station 26 (i.e., sector Dalcahue) was classified as "slightly toxic" (90 ± 4.1%). The samples were taken from the central zones of the studied channels and fjords. Since toxicologically these central areas are not polluted, any possible effects of aquaculture activities are expected to be more local in scope.
Investigaciones Marinas, 2003
Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering, May 1, 2001
... 4 Green, CJ, Cockshutt, NA and King, L. Dimethyl ether as a methanol ignition improver: subst... more ... 4 Green, CJ, Cockshutt, NA and King, L. Dimethyl ether as a methanol ignition improver: substitution requirements and exhaust emissions impact. ... 19 flC was observed using the MTBEethanol blend. RH Use of ethyl-t-butyl ether (ETBE) as a gasoline ...
This work presents for the first time a systematic study on the optimization of the electrochemic... more This work presents for the first time a systematic study on the optimization of the electrochemical cleaning time of a mercury film when it is used as a working electrode material in the analysis of toxic metals, such as Pb 2+ , used as model metal, in real samples by SWASV.
Revista De Biologia Marina Y Oceanografia, Mar 26, 2015
Revista Direito E Politica, 2012
A proporcionalidade é uma regra de interpretação e aplicação do direito. No entanto, não está mui... more A proporcionalidade é uma regra de interpretação e aplicação do direito. No entanto, não está muito bem sedimentado na doutrina brasileira seu verdadeiro conceito e sua correta forma de utilização, pois há autores que misturam teorias diferentes, incompatíveis entre si, desencadeando certas confusões. Nesse sentido foi realizado o presente trabalho, com vistas a analisar a proporcionalidade e sua aplicação, tendo como fundamentos obras de autores nacionais e estrangeiros a respeito da distinção entre regras e princípios, inclusive para se chegar a uma posição se esta é sinônimo ou não da razoabilidade, como sustentam alguns. Ao final, concluiu-se que a proporcionalidade é uma regra, utilizada para solução de conflitos entre princípios por meio da aplicação de suas sub-regras, diferentemente da razoabilidade.
The user has requested enhancement of the downloaded file.
El crucero oceanográfico CIMAR 7 Fiordos se realizó en dos etapas, la primera entre el 7 y el 21 ... more El crucero oceanográfico CIMAR 7 Fiordos se realizó en dos etapas, la primera entre el 7 y el 21 de julio 2001 (46 estaciones) y la segunda entre el 11 y 27 de noviembre 2001 (47 estaciones), abarcando desde la boca del Guafo (43 o 30' S) hasta el fiordo Aysén (45 o 30' S). En cada una de las etapas se registró la temperatura y salinidad. Además, se tomaron muestras de agua para el análisis de oxígeno disuelto y nutrientes (fosfato, nitrato y silicato). Las estaciones oceanográficas utilizadas para este estudio se distribuyeron a lo largo de la boca del Guafo, canal Moraleda y fiordo Aysén. Con esta información se prepararon secciones verticales para cada una de las características antes mencionadas, realizándose un análisis de la variabilidad estacional e interanual al comparar con otros cruceros realizados en la zona.
Latin American Journal of Aquatic Research
ABSTRACT
Latin American Journal of Aquatic Research
ABSTRACT. Medusae collected in winter and spring 2007 were analyzed in a longitudinal transect ma... more ABSTRACT. Medusae collected in winter and spring 2007 were analyzed in a longitudinal transect made between the Boca de Guafo and Elefantes Fjord, southern Chile. A total of 30 species were identified, Hydromedusae (29) and Scyphozoa (1), where Bougainvillia macloviana, ...
Deep Sea Research Part A. Oceanographic Research Papers, 1979
... WHITE (1969) showed a possible source of the Peru-Chile Undercurrent to be off Peru around 5 ... more ... WHITE (1969) showed a possible source of the Peru-Chile Undercurrent to be off Peru around 5 to 10 S. This conclusion is based on charts of acceleration potential relative to 500db and the distribution of salinity and oxygen on the 120-and 160-cl (ton)-1 isanosteric surfaces ...
The International journal of prosthodontics
The International journal of prosthodontics
Mechanical analyses of idealized crown-cement-tooth systems through finite element analysis (FEA)... more Mechanical analyses of idealized crown-cement-tooth systems through finite element analysis (FEA) has provided valuable insight concerning design parameters and materials that favor lower stress patterns. However, little information regarding variation of basic preparation guidelines in stress distribution has been available. The primary objective of this study was to evaluate maximum principal stresses on a molar crown veneer plus core system natural tooth configuration preparation with variations in the ratio of proximal axial length (PAL) to buccal axial length (BAL) as well as loading condition and position. Three-dimensional models comprising a crown veneer (porcelain), crown core (zirconia), cement layer, and tooth preparation (4.2 mm BAL with PAL reductions of 0.8 mm, 1.0 mm, and 1.2 mm) yielding BAL:PAL ratios of 1.23, 1.31, and 1.4 were designed by computer software (Pro/Engineering). The models were imported into an FEA software (Pro/Mechanica), with all degrees of freedom constrained at the root surface of the tooth preparation. Each tooth preparation crown configuration was evaluated under a vertical (axial) 200 N load, and under a combined vertical 200 N and horizontal (buccally) 100 N load applied at different positions from the central fossa to the cusp tip. Maximum principal stress (MPS) was determined for the crown core for each crown BAL:PAL ratio, loading condition, and position. Under both vertical and combined loading conditions, the highest MPSs were located at the occlusal region and in the occlusogingival region of the ceramic core. MPS values increased in the proximal region as the BAL:PAL ratio increased. Combined loading resulted in a general increase in MPS compared to vertical loading. Increasing the BAL:PAL ratio (reducing the proximal axial length of the preparation) acted as a stress concentrator at regions near the crown margins, suggesting this area may be vulnerable to damage from fit adjustment as well as during function. Such increases in stress concentration should be considered in clinical scenarios, especially when inherent flaws are present in the material, since extensive high-magnitude tensile stress fields have been noted under all loading conditions.
Investigaciones Marinas, 2007
A study of the ecotoxicological quality of surface sediment was carried out on samples collected ... more A study of the ecotoxicological quality of surface sediment was carried out on samples collected in the main fjords and interior channels between Reloncaví and Corcovado gulfs. The surface sediment samples were taken with a box corer and analyzed for organic matter content and grain size. Dissolved oxygen was measured in water samples taken 10 m off the bottom. The ecotoxicological evaluation of the sediments was performed using fertilization assays with gametes of Arbacia spatuligera (EPA/600/4-91/003). A fertilization rate of 95%, similar to that of the controls, was achieved. Therefore, the sediments at the sampled stations located in the middle of the channels were classified as nontoxic. Only the sediment at Station 26 (i.e., sector Dalcahue) was classified as "slightly toxic" (90 ± 4.1%). The samples were taken from the central zones of the studied channels and fjords. Since toxicologically these central areas are not polluted, any possible effects of aquaculture activities are expected to be more local in scope.
Investigaciones Marinas, 2003
Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering, May 1, 2001
... 4 Green, CJ, Cockshutt, NA and King, L. Dimethyl ether as a methanol ignition improver: subst... more ... 4 Green, CJ, Cockshutt, NA and King, L. Dimethyl ether as a methanol ignition improver: substitution requirements and exhaust emissions impact. ... 19 flC was observed using the MTBEethanol blend. RH Use of ethyl-t-butyl ether (ETBE) as a gasoline ...
This work presents for the first time a systematic study on the optimization of the electrochemic... more This work presents for the first time a systematic study on the optimization of the electrochemical cleaning time of a mercury film when it is used as a working electrode material in the analysis of toxic metals, such as Pb 2+ , used as model metal, in real samples by SWASV.
Revista De Biologia Marina Y Oceanografia, Mar 26, 2015
Revista Direito E Politica, 2012
A proporcionalidade é uma regra de interpretação e aplicação do direito. No entanto, não está mui... more A proporcionalidade é uma regra de interpretação e aplicação do direito. No entanto, não está muito bem sedimentado na doutrina brasileira seu verdadeiro conceito e sua correta forma de utilização, pois há autores que misturam teorias diferentes, incompatíveis entre si, desencadeando certas confusões. Nesse sentido foi realizado o presente trabalho, com vistas a analisar a proporcionalidade e sua aplicação, tendo como fundamentos obras de autores nacionais e estrangeiros a respeito da distinção entre regras e princípios, inclusive para se chegar a uma posição se esta é sinônimo ou não da razoabilidade, como sustentam alguns. Ao final, concluiu-se que a proporcionalidade é uma regra, utilizada para solução de conflitos entre princípios por meio da aplicação de suas sub-regras, diferentemente da razoabilidade.
The user has requested enhancement of the downloaded file.
El crucero oceanográfico CIMAR 7 Fiordos se realizó en dos etapas, la primera entre el 7 y el 21 ... more El crucero oceanográfico CIMAR 7 Fiordos se realizó en dos etapas, la primera entre el 7 y el 21 de julio 2001 (46 estaciones) y la segunda entre el 11 y 27 de noviembre 2001 (47 estaciones), abarcando desde la boca del Guafo (43 o 30' S) hasta el fiordo Aysén (45 o 30' S). En cada una de las etapas se registró la temperatura y salinidad. Además, se tomaron muestras de agua para el análisis de oxígeno disuelto y nutrientes (fosfato, nitrato y silicato). Las estaciones oceanográficas utilizadas para este estudio se distribuyeron a lo largo de la boca del Guafo, canal Moraleda y fiordo Aysén. Con esta información se prepararon secciones verticales para cada una de las características antes mencionadas, realizándose un análisis de la variabilidad estacional e interanual al comparar con otros cruceros realizados en la zona.
Latin American Journal of Aquatic Research
ABSTRACT
Latin American Journal of Aquatic Research
ABSTRACT. Medusae collected in winter and spring 2007 were analyzed in a longitudinal transect ma... more ABSTRACT. Medusae collected in winter and spring 2007 were analyzed in a longitudinal transect made between the Boca de Guafo and Elefantes Fjord, southern Chile. A total of 30 species were identified, Hydromedusae (29) and Scyphozoa (1), where Bougainvillia macloviana, ...
Deep Sea Research Part A. Oceanographic Research Papers, 1979
... WHITE (1969) showed a possible source of the Peru-Chile Undercurrent to be off Peru around 5 ... more ... WHITE (1969) showed a possible source of the Peru-Chile Undercurrent to be off Peru around 5 to 10 S. This conclusion is based on charts of acceleration potential relative to 500db and the distribution of salinity and oxygen on the 120-and 160-cl (ton)-1 isanosteric surfaces ...
The International journal of prosthodontics
The International journal of prosthodontics
Mechanical analyses of idealized crown-cement-tooth systems through finite element analysis (FEA)... more Mechanical analyses of idealized crown-cement-tooth systems through finite element analysis (FEA) has provided valuable insight concerning design parameters and materials that favor lower stress patterns. However, little information regarding variation of basic preparation guidelines in stress distribution has been available. The primary objective of this study was to evaluate maximum principal stresses on a molar crown veneer plus core system natural tooth configuration preparation with variations in the ratio of proximal axial length (PAL) to buccal axial length (BAL) as well as loading condition and position. Three-dimensional models comprising a crown veneer (porcelain), crown core (zirconia), cement layer, and tooth preparation (4.2 mm BAL with PAL reductions of 0.8 mm, 1.0 mm, and 1.2 mm) yielding BAL:PAL ratios of 1.23, 1.31, and 1.4 were designed by computer software (Pro/Engineering). The models were imported into an FEA software (Pro/Mechanica), with all degrees of freedom constrained at the root surface of the tooth preparation. Each tooth preparation crown configuration was evaluated under a vertical (axial) 200 N load, and under a combined vertical 200 N and horizontal (buccally) 100 N load applied at different positions from the central fossa to the cusp tip. Maximum principal stress (MPS) was determined for the crown core for each crown BAL:PAL ratio, loading condition, and position. Under both vertical and combined loading conditions, the highest MPSs were located at the occlusal region and in the occlusogingival region of the ceramic core. MPS values increased in the proximal region as the BAL:PAL ratio increased. Combined loading resulted in a general increase in MPS compared to vertical loading. Increasing the BAL:PAL ratio (reducing the proximal axial length of the preparation) acted as a stress concentrator at regions near the crown margins, suggesting this area may be vulnerable to damage from fit adjustment as well as during function. Such increases in stress concentration should be considered in clinical scenarios, especially when inherent flaws are present in the material, since extensive high-magnitude tensile stress fields have been noted under all loading conditions.