RESUMO A treliça é uma estrutura triangular rígida, com resistência aos esforços normais, podendo ser utilizada em telhados, mezaninos, torres de energia, de telecomunicações e pontes. Logo é possível afirmar que esse sistema estrutural apresenta uma grande relevância no cenário da engenharia de estruturas. Nesta pesquisa é utilizado um método probabilístico de otimização global baseado em inteligência coletiva ou inteligência de enxame, com aplicações promissoras em diversos campos das ciências aplicadas, o Algoritmo de Colônia de Vagalumes (ACV), para determinação do peso mínimo de uma treliça de benchmark. Foi conduzida uma análise de sensibilidade com os parâmetros do algoritmo como: população (Npop), número de iterações (Ngen), parâmetro de aleatoriedade α, fator de atratividade β e parâmetro de absorção de luz (γ). A treliça utilizada nos testes foi uma estrutura de benchmark com 10 barras e essa foi otimizada obtendo um valor de peso mínimo em torno de 2284 kg, tal valor quando comparado a outros trabalhos da literatura mostram a efetividade do método adotado nesse trabalho. O software utilizado para as implementações e simulação das treliças foi o MATLAB®.

ABSTRACT The truss is a rigid triangular structure, with resistance to normal load, and can be used on roofs, mezzanines, energy towers, telecommunications and bridges. Soon it is possible to state that this structural system has great relevance in the structural engineering scenario. This research uses a probabilistic method of global optimization based on collective intelligence or swarm intelligence, with promising applications in several fields of applied sciences, the Firefly Algorithm (FA), to determine the minimum weight of a benchmark truss. A sensitivity analysis was carried out with the parameters of the algorithm, such as the population (Npop), the number of iterations (Ngen), randomness parameter α, attractiveness factor β , and light absorption parameter (γ). The truss used in the tests was a benchmark structure with 10 bars, and this was optimized, obtaining a minimum weight value of around 2284 kg. When compared to other works in the literature, such value shows the effectiveness of the method adopted in this work. The software used for the implementations and simulation of the trusses was MATLAB®.

Resumo Este artigo reporta as atividades in vitro antiproliferativa, atiprotozoárica, anti-herpética e antimicrobiana de 32 extratos orgânicos provenientes de 14 esponjas marinhas e 14 corais coletados no litoral nordestino brasileiro. Os extratos etanólicos das esponjas Amphimedon compressa e Tedania ignis, e o extrato acetônico de Dysidea sp. demonstraram resultados promissores em relação aos efeitos antiproliferativos frente as linhagens celulares A549, HCT-8, PC-3 pelo método da sulforrodamina B, mas sem especificidade. Em relação à atividade antiprotozárica, os extratos etanólico de Amphimedon compressa e acetônico e etanólico de Dysidea sp. apresentaram atividade contra Leishmania amazonensis e Trypanosoma cruzi através do método de expressão de β-galactosidase em células THP-1. Na investigação preliminar de atividade antiviral frente ao vírus Herpes simplex tipo 1 (cepa KOS), os extratos etanólicos das esponjas Amphimedon compressa, Haliclona sp. e Chondrosia collectrix inibiram mais de 50% da replicação viral. O extrato etanólico da esponja Haliclona sp. demonstrou resultados promissores para atividade anti-herpética com altos índices de seletividade para as cepas KOS (IS >50) e 29R (IS>79) frente ao VHS-1 e cepa 333 (IS>108) frente ao VHS-2. O extrato etanólico da esponja Amphimedon compressa exibiu uma pequena atividade contra Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli pelo método de difusão em disco. De acordo com os resultados apresentados, os extratos das esponjas Amphimedon compressa, Tedania ignis e Dysidea sp. serão selecionados para futuros estudos de isolamento e identificação dos compostos bioativos para as atividades antiproliferativa e antiprozoárica. O extrato etanólico de Haliclona sp. será investigado por possuir atividade relevante anti-herpética.

Abstract This paper reports the in vitro antiproliferative effects, antiprotozoal, anti-herpes and antimicrobial activities of 32 organic extracts of 14 marine sponges and 14 corals collected in northeast Brazilian coast. The ethanolic extracts of the sponges Amphimedon compressa and Tedania ignis, and the acetone extract of Dysidea sp. showed relevant results concerning the antiproliferative effects against A549, HCT-8, and PC-3 cell lines by sulforhodamine B assay, but also low specificity. Concerning the antiprotozoal screening, the ethanolic extract of Amphimedon compressa and the acetone and ethanolic extracts of Dysidea sp. were the most active against Leishmania amazonensis and Trypanosoma cruzi expressing β-galactosidase in THP-1 cells. In the preliminary anti-HSV-1 (KOS strain) screening, the ethanolic extracts of the sponges Amphimedon compressa, Haliclona sp. and Chondrosia collectrix inhibited viral replication by more than 50%. The most promising anti-herpes results were observed for the ethanolic extract of Haliclona sp. showing high selective indices against HSV-1, KOS and 29R strains (SI> 50 and >79, respectively), and HSV-2, 333 strain (IS>108). The results of the antibacterial screening indicated that only the ethanolic extract of Amphimedon compressa exhibited a weak activity against Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli by the disk diffusion method. In view of these results, the extracts of Amphimedon compressa, Tedania ignis and Dysidea sp. were selected for further studies aiming the isolation and identification of the bioactive compounds with antiproliferative and/or antiprotozoal activities. The relevant anti-herpes activity of the ethanolic extract of Haliclona sp. also deserves special attention, and will be further investigated.

Resumo Nós objetivamos neste estudo, utilizar indicadores ambientais como método quantitativo para avaliar e discutir sobre o fluxo de nitrogênio (TN) e fósforo (TP) na etapa final de crescimento (terminação) de tilápia-do-nilo (Oreochromis niloticus) em viveiro escavado. A carga de TN e TP, o balanço de massa, a entrada de nutrientes via ração e o TN e TP convertido em biomassa de peixe foram os indicadores ambientais utilizados neste estudo. Durante o ciclo produtivo (128 dias), o sistema exportou 15.931 g NT e 4.189 g PT os quais foram relacionadas às quantidades de alimento fornecido (r Pearson = 0,8825 e r = 0,8523, respectivamente), corroborada pela conversão alimentar (1,61:1). Os indicadores evidenciaram que 26% NT e 45% PT foram revertidos em biomassa de peixe, 62% NT e 40% PT ficaram retidos no viveiro e 12% NT e 15% PT foram exportados via efluente. O maior aporte de nutrientes gerado pelo sistema e exportado via efluente foi verificado nas fases III e IV. Este resultado é corroborado pelas taxas de conversão alimentar de 2,14 e 2,21:1 obtida nestas fases, fato explicado pela quantidade de ração ofertada e pelo metabolismo dos peixes. A aplicação dos indicadores ambientais mostrou ser uma ferramenta eficiente para quantificar o fluxo de TN e TP produzidos durante a etapa final de crescimento de tilápia-do-nilo e com isso orientar práticas de manejo mais sustentáveis. Com vistas à sustentabilidade ambiental da atividade, a implantação de boas práticas de manejo tais como o melhor controle da quantidade de alimento ofertado levaria a menor perda de NT e PT para a água. Além disso, o uso de rações de melhor qualidade permitiria maior eficiência de assimilação desses nutrientes.

Abstract We aimed in this study utilize environmental indicators as a quantitative method to evaluate and discuss the nitrogen (TN) and phosphorus (TP) flux by a production stage grow-out (termination) of Nile tilapia (Oreochromis niloticus) in fishpond. The TN and TP load, the mass balance, the input of TN and TP via feed and the converted nutrients in fish biomass are the environmental indicators applied in this study. During the production cycle (128 days), the system exported 15,931 g TN and 4,189 g TP that were related to the amount of feed supplied (r Pearson = 0.8825 and r = 0.8523, respectively), corroborated by the feed conversion ratio (1.61:1). The indicators showed that 26% TN and 45% TP were reversed into fish biomass, 62% TN and 40% TP were retained in the fishpond, and 12% TN and 15% TP were exported via effluent. The largest contribution of nutrients generated by the system and exported via effluent was observed in phase III and IV. This result is supported by the feed conversion ratio 2.14 and 2.21:1 obtained at this phase, a fact explained by the amount of feed offered and the fish metabolism. Application of environmental indicators showed to be an efficient tool to quantify flux of TN and TP produced during the grow-out period of Nile tilapia and therefore, guide management practices more sustainable. Concerning the environmental sustainability of the activity the implementation of best management practices such as the better control of the feed amount offered would lead to a smaller loss of TN and TP to the water. Furthermore, the use of better quality feeds would allow greater nutrient assimilation efficiency.

Resumo A descarga de fósforo e nitrogênio via efluente do sistema intensivo de truticultura foi quantificada através da utilização de indicadores ambientais. As cargas de nutrientes, o balanço de massa, a quantidade estimada de nutrientes na ração e a quantidade de nutrientes convertidos em biomassa de peixes foram calculados com base nas concentrações de fósforo (P) e nitrogênio (N) na ração e na água. Da ração oferecida, 24,75 kg estavam disponíveis como P e 99,00 kg como N, destes, 9,32 kg de P (38%) e 29,12 kg de N (25%) foram convertidos em biomassa de peixe e 15,43 kg P (62%) e 69,88 kg N (75%) foram exportados via efluente. As cargas e o balanço de massa mostram a descarga excessiva de nutrientes via efluente, corroborado pela taxa de conversão alimentar (2,12:1), devido à baixa eficiência na utilização da ração, portanto, propõe-se a utilização deste parâmetro zootécnico como indicador ambiental. Além disso, as práticas de manejo alimentar não são adequadas, destacando a baixa frequência de alimentação durante o dia, quantidade excessiva e baixa qualidade da alimentação ofertada. Esses resultados demonstram a necessidade de manejo alimentar adequado e de monitoramento do efluente.

Abstract The phosphorus and nitrogen discharge via effluent of intensive trout farming system was quantified through the use of environmental indicators. The nutrient loads, the mass balance, the estimated amount of nutrients in feed and the amount of nutrients converted in fish biomass were calculated based on the concentrations of phosphorus (P) and nitrogen (N) in the feed and in the water. Of the offered feed, 24.75 kg were available as P and 99.00 kg as N, of these, 9.32 kg P (38%) and 29.12 kg N (25%) were converted into fish biomass and 15.43 kg P (62%) and 69.88 kg N (75%) were exported via effluent. The loads and the mass balance show the excessive discharge of nutrients via effluent, corroborated by the feed conversion ratio (2.12:1) due to the low efficiency of feed utilization, therefore, it is proposed the use of this zootechnical parameter as environmental indicator. In addition, feed management practices are not adequate, highlighting the low frequency of feeding during the day, excessive amount and low quality of feed offered. These results demonstrate the need for adequate feed management and the need for careful monitoring of effluent.

The steam curing process is used to accelerate cement hydration reactions with the purpose to enhance the mechanical strength of concrete at early ages, since hydration reactions are temperature dependent. The maturity concept is used in order to evaluate the influence of temperature on the development of mechanical properties of concrete. This method estimates the development of these properties according to the temperature history of concrete along the curing process. The temperature influence can be indicated by the apparent activation energy (AE) value. The higher is the AE value, the more energy will be necessary to start the reactions, and thus the velocity of these reactions will be affected by temperature. This work is based on an experimental study of steam-cured concrete made with 5% and 10% of rice husk ash (RHA) addition in which the development of some mechanical properties was investigated. The rice husk ash used was obtained from uncontrolled autocombustion of rice husk, in an open chamber, without any control of temperature and burning time. The mechanical propertie investigated was the compressive strength. The results indicate the influence of RHA addition and its dosage on the hydration reactions of cement and the mechanical properties of steam-cured concrete.

La cura termal es un proceso utilizado para acelerar las reacciones de hidratación del cemento portland con el objetivo de obtener beneficios de resistencia mecánica a edades tempranas del hormigón, puesto que la temperatura opera en la velocidad de estas reacciones. Para una mejor evaluación de la influencia que ejerce la temperatura sobre el desarrollo de las propiedades mecánicas del concreto, se utiliza el concepto de madurez. El método de madurez estima el desarrollo de las propiedades mecánicas del concreto relacionado con la historia de las temperaturas durante el proceso de curado. La influencia de la temperatura puede ser indicada por la energía de activación (EA) aparente. Cuanto mayor sea el valor de la EA, mayor será la potencia necesaria para iniciar la reacción y, por lo tanto, la velocidad de estas reacciones se verá afectada por la temperatura. Este trabajo presenta los resultados de la determinación experimental de la resistencia a la compresión del hormigón fabricado con adición de cenizas de cascarilla de arroz (CCA), producido por la combustión no controlada de la corteza, en cámara abierta, sin control de la temperatura ni del tiempo de combustión. Como propiedad mecánica, se investigó la resistencia a la compresión. Los resultados señalan la influencia de la adición de CCA y su posología en las reacciones de hidratación del cemento y las propiedades mecánicas del hormigón con cura termal.

Resumo O objetivo deste estudo foi avaliar os fatores ambientais determinantes das mudanças na estrutura do fitoplâncton em escala espacial (alto, médio e baixo curso) e temporal (seca e chuva) em um rio eutrófico tropical (rio Almada, nordeste do Brasil). No período de estudo, a precipitação acumulada mensal foi abaixo da média histórica, resultando na redução da vazão, principalmente no período chuvoso. A concentração de ortofosfato foi elevada nos pontos de amostragem. A clorofila a do fitoplâncton aumentou de montante para jusante. Geitlerinema splendidum (S1) e Chlamydomomas sp. (X2) foram as espécies mais abundantes no alto curso e várias espécies de diatomáceas (D), Euglenophyceae (W1, W2) e Chlorophyceae (X1) no médio e/ou baixo curso. Os grupos funcionais foram característicos de ambientes lóticos, rasos, com baixa disponibilidade de luz, rico em matéria orgânica e eutrófico. Concluímos que a estrutura da comunidade fitoplanctônica foi sensível às mudanças na vazão e na disponibilidade de nutrientes em escala espacial e temporal em um rio tropical.

Abstract This study aims to evaluate the environmental factors determining of the changes in phytoplankton structure in spatial (upper, middle and lower course) and seasonal (dry and rainy period) scales in a eutrophic river (Almada River, northeastern Brazil). In the study period, total accumulated rainfall was below of the historic average, resulting in flow reduction, mainly in rainy period. High orthophosphate concentration was found at the sampling sites. Phytoplankton chlorophyll a increased from upstream to downstream. Geitlerinema splendidum (S1) and Chlamydomonas sp. (X2) were the most abundant species in the upper course and several species of diatoms (D), Euglenophyceae (W1, W2) and Chlorophyceae (X1) in the middle and lower course. The functional groups were found to be characteristic of lotic ecosystem, shallow, with low light availability, rich in organic matter and eutrophic environments. We conclude that phytoplankton community structure was sensitive to change of the river flow and nutrient availability in spatial and seasonal scale in a tropical river.

The aim of this research was to find the relation between facial asymmetry and loss of continuity in median line of maxillary and mandibular teeth. A descriptive study was carried out in 18 subjects with facial asymmetry with surgical indication and observed at the Division of Oral and Maxillofacial Surgery of the Universidad de La Frontera. In all of them the grade of facial asymmetry and the relation in median line of the maxillary and mandibular teeth was evaluated using the t student test considering p value < 0.05; all the evaluations were executed using 2D photography of the face and tooth obtained with standardized conditions. In all the subjects we observed dental asymmetry with almost 7 mm from the median line; statistical relations between dental asymmetry and facial asymmetry. It is concluded that in subjects asking for dental asymmetry treatment a facial evaluation is necessary in view of the relation with skeletal facial deformity.

El objetivo de esta investigación es identificar la relación entre la asimetría facial y la pérdida de contacto en línea mediana entre dientes maxilares y mandibulares. Se realizó un estudio descriptivo en 18 sujetos portadores de asimetría facial que consultaron en la División de Cirugía Oral y Maxilofacial de la Universidad de La Frontera por tratamiento quirúrgico de la asimetría. En todos ellos se evaluó la presencia y grado de la asimetría facial y la presencia y desvío desde la línea mediana facial del punto mediano mandibular y maxilar mediante la prueba estadística t de student considerando un valor de p <0,05; todas las evaluaciones fueron realizadas mediante fotografías 2D de rostro y dientes obtenidas en condiciones estandarizadas. Se identificó que todos los sujetos portadores de asimetría facial presentaron asimetría dentaria; los desvíos dentarios fueron de casi 7 mm y existió relación estadísticamente significativa entre desvío facial y desvío dentario. Se concluye que los sujetos con asimetría dentaria pueden presentar asimetría facial de forma que la evaluación esqueletal del rostro es necesaria para realizar un diagnóstico correcto.

A commercial casein hydrolysate was microencapsulated in liposomes produced with non-purified soy lecithin, cryoprotected with two different disaccharides and lyophilized. The encapsulation efficiency of casein hydrolysate ranged from 30 to 40%. The powders were analyzed by differential scanning calorimetry (DSC), scanning electron micrography (SEM), infrared spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). DSC data revealed the presence of an exothermal transition in empty lyophilized liposomes, which was ascribed to the presence of a quasicrystalline lamellar phase (intermediary characteristics between the Lβ and Lc phases). The addition of peptides to the liposomal system caused the disappearance of this exothermic phenomenon, as they were located in the polar headgroup portion of the bilayer, causing disorder and preventing the formation of the quasicrystalline phase. Infrared data indicated the presence of the peptides in the lyophilized formulations and showed that the cryoprotectants interacted effectively with the polar heads of phospholipids in the bilayer.

During the pneumatic conveying of plastic pellets, it has been observed that materials with similar physical characteristics may develop a substantial difference in pressure drop. In this work, the pressure drop in a particle-laden 2.7 meter long horizontal channel with circular cross-section is presented from an experimental perspective. Experiments are carried out for cylindrical polystyrene beads with an average diameter of 3.2 mm and mass loadings of 0.06 to 0.11 (kg particles/kg gas). The air mass flow rate was studied in the range from 0.085 kg/s to 0.170 kg/s. The pressure drop curve is shown as a function of air velocity and particle load. Response surface methodology showed high statistical significance for air velocity, particle load and their cross-relation.

O presente estudo foi desenvolvido no sistema fluvial do rio Mato Grosso que compõe uma drenagem costeira da Serra do Mar. Foi analisado o hábito alimentar e o ritmo alimentar diário de Pimelodella lateristriga a partir de amostras obtidas em coletas de 24 horas, com intervalos de 4 horas, em junho-julho-setembro/2006 e janeiro- fevereiro/2007. A dieta foi avaliada a partir do Índice Alimentar (IAi) e o ritmo alimentar diário, com base no Índice de Repleção Estomacal (GFI) dos peixes. A dieta de P. lateristriga foi composta por 37 itens, sendo os insetos aquáticos os mais abundantes. O IAi revelou que Diptera, Trichoptera e Ephemeroptera somaram 90% da dieta, sendo, portanto, os invertebrados autóctones os itens mais consumidos. Pimelodella lateristriga concentrou sua atividade alimentar no período noturno (10:00 até 14:00 horas) com diferenças significativas (F = 16,11; gl = 5; p < 0,05) entre os horários diurnos e noturnos. Entre os horários 6 am e 6 pm a atividade de forrageamento foi gradualmente reduzida. Concluímos que P. lateristriga possui dieta insetívora e ritmo alimentar noturno com pico de atividade entre 10:00 até 14:00 horas.

The present study was carried out in Mato Grosso fluvial system, a costal drainage from Serra do Mar. We analysed the diet and the feeding daily rhythm of Pimelodella lateristriga from samples carried out during 24 hours over a 4 hour fishing interval, in June, July and September, 2006 as well as in January and February, 2007. Diet was described from the Feeding Index (IAi) and feeding daily rhythm was verified through the Gut Fullness Index (GFI). Pimelodella lateristriga diet was composed of 37 items, being aquatic insects the most important ones. IAi analysis revealed that Diptera, Trichoptera and Ephemeroptera amounted to 90% of the diet. Autochthonous invertebrates were the most important consumed items. Pimelodella lateristriga concentrated its feeding activities in the nocturnal period (10:00 PM to 2:00 AM) with marked significant differences (F = 16.11; gl = 5; p < 0.05) between each diurnal and nocturnal periods. Between 6:00 AM and 6:00 PM, foraging activity was gradually reduced. We concluded that P. lateristriga has an insectivorous diet and a nocturnal feeding habit with greater activity between 10:00 PM to 2:00 AM.

In recent times, the microalgae Spirulina platensis has been used as a functional ingredient in several food applications; its process involving drying and storage steps. Moisture equilibrium data for adsorption isotherms of microalgae Spirulina were investigated at 10, 20 and 30ºC and for desorption, at 40, 50 and 60ºC, using the gravimetric static method. The experimental data were analyzed by GAB and BET models. The GAB equation showed the best fitting to the experimental data with R² ≈ 99% and MRE < 10%. The water surface area values calculated by GAB and BET models were very similar. The isosteric heats were determined by application of Clausius-Clapeyron equation to sorption isotherms obtained from the best-fitting equation. The isosteric heat and the entropy of desorption isotherm presented similar behavior, with a sharp change in an equilibrium moisture content of 10%. The enthalpy-entropy compensation theory was applied to the isotherms, indicating that they are enthalpy-controlled.

Von Recklinghausen’s disease, or type I neurofibromatosis (NF-1), is an autosomal dominant condition with a varied clinical expression. Disease manifestations may range from café au lait spots of the skin to severe cosmetic and functional complications that affect bone and nervous tissues. Oral manifestations of NF-1 are common, affecting approximately 72% of patients. We report a case of NF-1 with neurofibromatous lesions of the lower alveolar bridge and tongue. Resection was indicated due to the difficulty of maintaining oral hygiene.

La enfermedad de Von Recklinghausen o Neurofibromatosis Tipo I (NF1) es una condición autosómica dominante que presenta una variada expresión clínica, con manifestaciones que van desde manchas tipo café con leche en piel a severas complicaciones estéticas y funcionales afectando los tejidos óseos y nerviosos. Las manifestaciones orales de la NF1 son comunes, afectando aproximadamente al 72% de los pacientes. Presentamos un caso de NF1 con lesiones neurofibromatosas afectando al reborde alveolar inferior y lengua, con indicación de excisión quirúrgica debido a la dificultad de higiene local.

Extratos orgânicos foram obtidos a partir das raízes de Canavalia ensiformis. Tais extratos foram avaliados a fim de determinar o potencial alelopático dos mesmos na germinação das sementes das plantas daninhas: Mimosa pudica, Cassia tora e Cassia occidentalis se mostrando bastante eficazes. Posteriormente, tais extratos foram submetidos a análises sistemáticas utilizando protocolos desenvolvidos em eletroforese capilar para a determinação de algumas classes de metabólitos secundários. Os protocolos desenvolvidos se mostraram altamente específicos sendo possível identificar 5 classes de compostos utilizando os mesmos extratos brutos. Alguns compostos identificados apresentaram potencial alelopático frente às sementes de plantas daninhas estudadas.

Organic extracts were obtained from roots of Canavalia ensiformis and evaluated for allelopathic potential on the germination of the weed seeds: Mimosa pudica, Cassia tora and Cassia occidentalis showing a strong allelopathic potential. After that, a systematic study of these crude extracts was made using specific protocols developed in capillary electrophoresis (CE) in order to determine some classes of secondary metabolites. Capillary electrophoresis protocols were highly specific, which makes it possible to identify 5 classes of compounds using the same crude extract samples and analyze them fartly. Some of the compounds identified show activity in the inhibition of seeds germination.

In the study of two interacting systems within the framework of microscopic theories, the correct treatment of the effective interaction between the fragments has been the most troubling problem, due to the technical difficulties in calculating the exchange terms. In the framework of the Generator Coordinate Method, and through a double projection technique, we obtain this effective interaction between two pairs of nucleons, taking into account the Coulomb exchange plus a nuclear part. Our treatment is useful in the analysis of the role of correlated nucleon pairs in photoabsorption experiments by nuclei.

Este trabalho propõe o desenvolvimento de um procedimento analítico para a determinação em linha de estanho em soluções analíticas empregando a técnica de espectrometria de absorção atômica com nebulização térmica em tubo metálico aquecido na chama (TS-FF-AAS) como alternativa ao uso da chama de óxido nitroso-acetileno em espectrometria de absorção atômica, cujo comburente apresenta um custo elevado frente ao ar comprimido. Foram avaliados parâmetros para a otimização do sistema, tais como: vazão do carregador (ar), volume de amostra injetada e concentração do ácido (HCl). Foi construída curva analítica linear [A= -0,00163 + 0,00319 [Sn], (r= 0,9998)] no intervalo de 10 a 80 mg Sn L-1. O limite de detecção, o desvio padrão relativo (n=12) e a freqüência analítica foram: 1,7 mg L-1 Sn, £ 2,7% and 120 h-1 respectivamente. O sistema TS-FF-AAS é uma alternativa para a determinação de Sn.

This work propose the development of analytical procedure for on line tin determination in analytical solutions by thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) as alternative to nitrous oxide-acetylene flame by atomic absorption spectrometry, whose oxidant presents high costs with respect to air. Parameters were evaluated for the optimization of the system: flow of the carrier (air), volume of injected sample and concentration of the acid (HCl). The linear analytical curve [A= -0,00163 +0,00319 Sn], (r = 0,9998) ] was constructed on interval of 10 the 80 mg L-1 Sn. The detection limit, the relative standard deviations (n=12) and analytical frequency were: 1,7 mg L-1 Sn, £ 2,7% and 120 h-1, respectively. The TS-FF-AAS is an alternative for the determination of Sn.