Abstract Plant-induced resistance can be an important component of soybean mites biological control programs. This work evaluates the preference of predatory mite Neoseiulus californicus (Acari: Phytoseiidae) to soybean plants under single and multiple herbivory conditions by two-spotted spider mite Tetranychus urticae (Acari: Tetranychidae), and velvetbean caterpillar Anticarsia gemmatalis (Lepidoptera: Noctuidae). Using a Y olfactometer, the following scenarios were evaluated: soybean with no infestation and soybean infested with A. gemmatalis; soybean infested with T. urticae and A. gemmatalis, and soybean infested with T. urticae and with both T. urticae and A. gemmatalis. Volatile compounds released by plants were analyzed and identified by a Trace GC Ultra gas chromatograph coupled to a mass spectrometer with a solid phase micro-extraction ion-trap. The predatory mite N. californicus preferred soybean plants infested with T. urticae compared to those infested with A. gemmatalis. Multiple infestation did not interfere with its preference to T. urticae. Multiple herbivory of T. urticae and A. gemmatalis modified the chemical profile of volatile compounds emitted by soybean plants. However, it did not interfere with the search behavior of N. californicus. Out of the 29 identified compounds only five promoted predatory mite response. Thus, regardless of single or multiple herbivory by T. urticae with or without A. gemmatalis, the indirect induced resistance mechanisms operate similarly. As such, this mechanism contributes to an increase in the encounter rate between predator and prey for N. Californicus and T. urticae, and the efficacy of biological control of mites on soybean.

Resumo A resistência induzida por plantas pode ser um importante componente dos programas de controle biológico de ácaros da soja. Este trabalho avalia a preferência do ácaro predador Neoseiulus californicus (Acari: Phytoseiidae) às plantas de soja sob condições de herbivoria simples e múltipla pelo ácaro-rajado Tetranychus urticae (Acari: Tetranychidae) e pela lagarta-da-soja Anticarsia gemmatalis (Lepidoptera: Noctuidae). Utilizando o olfatômetro Y, foram avaliados os seguintes cenários: soja sem infestação e soja infestada com A. gemmatalis; soja infestada com T. urticae e A. gemmatalis, e soja infestada com T. urticae e com T. urticae e A. gemmatalis. Os compostos voláteis liberados pelas plantas foram analisados e identificados por um cromatógrafo gasoso Trace GC Ultra acoplado a um espectrômetro de massas com uma armadilha de íons de microextração em fase sólida. O ácaro predador N. californicus preferiu plantas de soja infestadas com T. urticae em relação àquelas infestadas com A. gemmatalis. A infestação múltipla não interferiu na preferência por T. urticae. A herbivoria múltipla de T. urticae e A. gemmatalis modificou o perfil químico de compostos voláteis emitidos por plantas de soja. No entanto, não interferiu no comportamento de busca de N. californicus. Dos 29 compostos identificados apenas cinco promoveram resposta de ácaros predadores. Assim, independentemente da herbivoria simples ou múltipla por T. urticae com ou sem A. gemmatalis, os mecanismos de resistência induzida indiretamente operam de forma semelhante. Assim, esse mecanismo biológico contribui para o aumento da taxa de encontro entre predador e presa para N. Californicus e T. urticae, e para a eficácia do controle de ácaros em soja.

In order to typify the rabbit production systems in Ciego de Avila municipality, Cuba, quantitative and qualitative information of 49 rabbit farms were obtained. The Statistical Model of Impact Measuring was applied with the quantitative variables, which combine the factors analysis by the main components method with the hierarchical cluster, to typify the cases. The frequencies per typologies for qualitative variables were obtained. The rabbit production systems were typified into five groups: I) small farmers with land, younger, apply more mating (14.3 %) pardos. II) small farmers with land and older (42.9 %), III) small farmers without land, late weaning (12.5%), IV) medium farmers with land and semi-intensive reproductive management with low efficiency (28.6%) and V) technical system, with semi-intensive reproductive management with low efficiency (2.0%). In the farmers, the Cuban Brown race, Chinchilla and different crosses predominate. The feeding system in general was based on forage resources, supplementation and little use of protein plants, except Tithonia diversifolia in groups I, III and V. Regardless of the productive scales, technological alternatives that guarantee greater productive and reproductive efficiency are not applied in the feeding system. This study shows that these typologies should be considered to implement an agricultural extension system that contributes to the training of farmers and the management and application of sustainable technological alternatives with the use of endogenous resources.

Para tipificar los sistemas productores de conejos en el municipio Ciego de Ávila, Cuba, se obtuvo información cuantitativa y cualitativa de 49 fincas cunícolas. Con las variables cuantitativas se aplicó el modelo estadístico de medición de impacto, que combina el análisis de factores por el método de componentes principales con el conglomerado jerárquico, para tipificar los casos. Se obtuvieron las frecuencias por tipologías para las variables cualitativas. Los sistemas productores de conejos se tipificaron en cinco grupos: I) pequeños productores con tierra, menor edad, aplican más montas (14.3 %) por conejas, II) pequeños productores con tierra y mayor edad (42.9 %), III) pequeños productores sin tierra, destete tardío (12.5 %), IV) medianos productores con tierra y manejo reproductivo semi-intensivo con baja eficiencia (28.6 %) y V) sistema tecnificado, con manejo reproductivo semi-intensivo con baja eficiencia (2.0 %). En los productores predomina la raza Pardo cubano, Chinchilla y diferentes cruces. El sistema de alimentación en general fue a partir de recursos forrajeros, suplementación y escaso uso de plantas proteicas, excepto Tithonia diversifolia en el grupo I, III y V. Independientemente de las escalas productivas, en el sistema de alimentación no se aplican alternativas tecnológicas que garanticen mayor eficiencia productiva y reproductiva. Este estudio muestra que se deben considerar estas tipologías para implementar un sistema de extensión agropecuario que contribuya a la capacitación de los productores y a la gestión y aplicación de alternativas tecnológicas sostenibles con la utilización de recursos endógenos.

Abstract This work produced glass foams from soda-lime glass bottles, bentonite, and alumina by the replica method. Compositions with different contents of bentonite (5, 10, 15, and 20 wt%) were prepared and heat-treated at 800 °C. In the alumina-added compositions, 50 wt% of the bentonite was replaced by the alumina. The influences of the content of bentonite (binder) and alumina addition were evaluated through the physical-mechanical properties. The results showed that the alumina did not promote a significant effect on physical and mechanical properties in most glass foams; the exception was the sample with 20 wt% bentonite+alumina, which presented better physical properties (lower linear shrinkage and density and greater porosity) when compared to its equivalent sample (without alumina). Foams with 5% of bentonite or bentonite+alumina showed higher linear shrinkage indexes and high densification. Samples with 15% of bentonite or bentonite+alumina showed the best combination of properties: higher porosity (79.2% and 80.2%), water absorption (58.8% and 59.7%), lower shrinkage index (25.5% and 29.4%), and good flexural strength (0.69 and 0.45 MPa).

Abstract A total of twenty-four breeding ewes from Pelibuey breed were used, divided into two treatments of 12 animals each, to determine the effect of natural shade on the behavior of these animals during grazing. In treatment one, they grazed in the system with natural shade and in treatment two, without shade. Each treatment included the three physiological states: non-pregnant cow, pregnant and lactating. Both groups grazed in two paddocks of natural grasses, of 1.3 ha: one without natural shade, and another with shade from the trees Casuarina equisetifolia (casuarina) and Samanea saman (carob tree). The grazing performance was recorded. Every 10 min., observations during six hours of grazing per day were recorded. Contingency table analysis was used to test the interaction between activities and system type, with and without shade, between activities and day session, and between activities and season for each system, with trees and without them. With the analysis of comparison of proportions (chi square), the time percentages were compared. There was interaction between the activities and the characteristics of the farms, with and without trees, and between the activities and the day session. The animals that had access to the shade of the trees spent more time grazing-walking. When they grazed with trees, they selected activities in the shade, such as rest and rumination. A higher proportion of grazing time was recorded during the morning session. In the system with trees, the highest proportions of grazing time were obtained in both seasons.

Resumen Se utilizaron 24 ovejas reproductoras de la raza Pelibuey, divididas en dos tratamientos, de 12 animales cada uno, para determinar el efecto de la sombra natural en la conducta de estos animales en pastoreo. En el tratamiento uno, pastorearon en el sistema con sombra natural y en el dos, sin sombra. Cada tratamiento incluyó los tres estados fisiológicos: vacías, gestantes y lactantes. Ambos grupos pastorearon en dos cuartones de pastos naturales, de 1.3 ha: uno sin sombra natural, y otro con sombra de los árboles Casuarina equisetifolia (casuarina) y Samanea saman (algarrobo). Se registró la conducta en pastoreo. Cada 10 min., se registraron las observaciones durante seis horas de pastoreo por día. Se utilizó un análisis de tablas de contingencia para probar la interacción entre las actividades y el tipo de sistema, con sombra y sin ella, entre las actividades y la sesión del día, y entre las actividades y la época para cada sistema, con árboles y sin ellos. Con el análisis de comparación de proporciones (chi cuadrado) se compararon los porcentajes del tiempo. Hubo interacción entre las actividades y las características de las fincas, con árboles y sin ellos, y entre las actividades y la sesión del día. Los animales que tuvieron acceso a la sombra de los árboles dedicaron más tiempo a pastar-caminar. Cuando pastorearon con árboles, seleccionaron las actividades a la sombra, como el descanso y la rumia. Se registró mayor proporción del tiempo en pastoreo durante la sesión de la mañana. En el sistema con árboles, se obtuvieron las mayores proporciones del tiempo en pastoreo, en ambas épocas.

Abstract In order to determine the typologies of sheep production systems in Ciego de Ávila province, the statistical model of impact measuring (SMIM) was applied, which combines the main components analysis with the hierarchical cluster method. An information matrix of 296 sheep farmers was used to define groups of farms. The main component analysis explained 71.83 % of the variability. In component 1, variables related to herd movement were identified and component 2 was associated with land tenure. Component 3 had to do with training and management, and component 4 with the age and farmers experience. Component 5 included the number of workers and technological aspects, and component 6 was related to the presence of trees. Five groups of sheep farmers were obtained: I) medium farmers with land from the private sector, II) small farmers without tendency of lands from the private sector, III) small farmers with land from both sectors, with a predominance of the private, IV) large farmers with land from both sectors and V) small farmers with land from both sectors with predominance of the state. The measured indicators explained the higher variability of sheep breeding in the province, in each region, and at the municipal level, Chambas, for the northern region, Ciego de Ávila, for the central region, and Venezuela for the southern region, were the municipalities with superior social, productive, technological and environmental indicators.

Resumen Para determinar las tipologías de los sistemas de producción de ovinos en la provincia Ciego de Ávila se aplicó el modelo estadístico de medición de impacto (MEMI), que combina el análisis de componentes principales con el método de conglomerados jerárquicos. Se utilizó una matriz de información de 296 productores de ovinos para definir grupos de fincas. El análisis de componentes principales explicó 71.83 % de la variabilidad. En la componente 1, se identificaron variables relacionadas con el movimiento de rebaño y la 2 se asoció con la tenencia de tierras. La componente 3 tuvo que ver con la capacitación y el manejo, y la 4 con la edad y experiencia de los productores. La 5 incluyó la cantidad de trabajadores y aspectos tecnológicos, y la componente 6 se relacionó con la presencia de árboles. Se obtuvieron cinco grupos de productores de ovinos: I) medianos productores con tierras del sector privado, II) pequeños productores sin tendencia de tierras del sector privado, III) pequeños productores con tierras de ambos sectores, con predominio del privado, IV) grandes productores con tierras de ambos sectores y V) pequeños productores con tierras de ambos sectores con predominio del estatal. Los indicadores medidos explicaron la mayor variabilidad de la crianza ovina en la provincia, en cada región, y a nivel de municipio. Chambas, para la región norte, Ciego de Ávila, para la central, y Venezuela para la región sur, fueron los municipios con superiores indicadores sociales, productivos, tecnológicos y ambientales.

Abstract The application of categorical principal component analysis is presented, with 22 qualitative variables measured in the study of ovine production systems in Ciego de Ávila province. The mathematical description of the method is stated using the loss function that is minimized by applying alternating least squares, which contemplate the transformation of any qualitative variable into variables of quantitative nature through optimal scaling. Cronback coefficient was used to measure the reliability of the questionnaire. Crossover tables were determined to verify the association among variables using the contingency coefficient, which is based on χ2 and its significance. All the processes were carried out using the IBM-SPSS program, version 22. The application of the categorical principal components analysis allowed to identify categorical variables that explained the greatest variance in ovine production system in Ciego de Ávila province.

Se presenta la aplicación del análisis de componentes principales categórico, con 22 variables cualitativas medidas en el estudio de los sistemas de producción de ovinos en la provincia Ciego de Ávila. Se expone la descripción matemática del método utilizando la función de pérdida que se minimiza al aplicar los mínimos cuadrados alternantes, que contemplan la transformación de cualquier variable cualitativa en variables de naturaleza cuantitativa a través del escalamiento óptimo. Se utilizó el coeficiente de Cronback para medir la fiabilidad del cuestionario. Se determinaron las tablas cruzadas para comprobar la asociación entre las variables mediante el coeficiente de contingencia, que se basa en χ2 y su significación. Todos los procesamientos se realizaron mediante el IBM-SPSS, versión 22. La aplicación del análisis de componentes principales categórico permitió identificar las variables categóricas que mayor varianza explicaron en el sistema de producción de ovinos en la provincia Ciego de Ávila.

Abstract: This article shows the results of a study on the evaluation of the use of the TDI (Traffic Densification Index) for the prediction of the behavior of a conventional asphalt mixture and two nano-modified asphalt mixtures (one with 2% of carbon nanotubes, CNTs, and another with 3% of organophilic nanoclay, NA) against permanent deformation. The mixtures were designed with equivalent granulometries and different asphalt binders (a conventional and two nano-modified binders). The design of the mixtures was made according to the Superpave method, and the TDI of the mixture was determined from the curves obtained in the compaction test (%Gmm vs number of cycles). For each mixture under study, two slabs measuring 50 x 18 x 5 cm were compacted on the BBPAC slabs compactor of IFSTTAR (Institut Français des Sciences et Technologies des Transports, de L'Aménagement et des Réseaux). These slabs were subsequently subjected to the permanent deformation test in the French traffic simulator, Orniéreur. The TDI obtained was compared with the performance of the mixtures in the permanent deformation test. The results obtained show that the TDI was not effective in predicting the behavior, in terms of permanent deformation, of asphalt mixtures with asphalt binders different from the conventional binder (nano-modified).

Resumen: Este artículo muestra los resultados de un estudio sobre la evaluación del uso del índice TDI (Traffic Densification Index) para la predicción del comportamiento de una mezcla asfáltica convencional y dos mezclas asfálticas nanomodificadas (una con 2% de nanotubos de carbono - NTC y otra con 3% de nanoarcilla organofilica - NA) frente a la deformación permanente. Las mezclas fueron diseñadas con granulometrías equivalentes y ligantes asfálticos distintos (un convencional y dos nanomodificados). El diseño de las mezclas fue realizado según el método Superpave y a partir de las curvas obtenidas en el ensayo de compactación (%Gmm vs número de giros) fue determinado el índice TDI de las mezclas. Para cada mezcla estudiada, fueron compactadas dos placas, con dimensiones de 50 x 18 x 5 cm, en la máquina compactadora BBPAC del IFSTTAR (Institut Français des Sciences et Techonologies des Transportes, de L’aménagement et des Réseaux); estas placas fueron, posteriormente, sometidas al ensayo de deformación permanente en el simulador de tráfico francés Orniéreur. El índice TDI obtenido fue comparado con el desempeño de las mezclas en el ensayo de deformación permanente. Los resultados obtenidos indican que el índice TDI no se mostró eficaz al momento de predecir el comportamiento, cuanto a la deformación permanente, de las mezclas asfálticas con ligante asfálticos distintos al convencional (nanomodificados).

Abstract: The obtaining of fatigue models of asphalt mixtures, are part of the procedures of advanced characterization of the material and are used for the design of pavements. However, there are several approaches to analysis and failure criteria that can be used. These approaches and criteria may not produce the same models of fatigue, resulting in different thicknesses of the asphalt surface in the pavement structure. This study presents the results of the influence of two approaches of analysis (phenomenological and accumulated dissipated energy) and two criteria of rupture (conventional and Pronk & Hopman) in obtaining fatigue models of the asphalt mixture, and its repercussion in the estimation of useful life of the asphalt surface in the pavement structure. The results show that the phenomenological approach is more conservative than the accumulated dissipated energy, as well as the Pronk & Hopman criterion in relation to the conventional criterion, that is, the type of approach and the criterion of rupture adopted will directly affect the final thickness of the projected asphalt surface.

Resumen: Obtener los modelos de fatiga de mezclas asfálticas es parte de los procedimientos de caracterización avanzada de este material y los mismos son utilizados para el diseño del pavimento. No obstante, existen diversos enfoques de análisis y criterios de rotura que pueden ser utilizados. Estos enfoques y criterios pueden producir modelos de fatiga diferentes y, en consecuencia, capas asfálticas con espesores diferentes en la estructura del pavimento. Este estudio presenta los resultados de la influencia de dos enfoques de análisis, fenomenológico y de energía disipada acumulada, y dos criterios de rotura, convencional y de Pronk & Hopman, en la obtención de los modelos de fatiga de la mezcla asfáltica, y su repercusión en la estimación de la vida útil de la capa en la estructura del pavimento. Los resultados muestran que el enfoque fenomenológico es más conservador que el de energía disipada acumulada, como también lo es el criterio de Pronk & Hopman en relación al criterio convencional, es decir, el tipo de enfoque y el criterio de rotura adoptado repercutirán directamente en el espesor final de la capa diseñada.

Abstract: The phenomenon of fatigue can be considered as one of the main causes of the asphalt Surface course failure. The Four-Point Bending Apparatus is the widespread equipment used to determine the fatigue resistance of asphalt mixtures. Worldwide there are several standard procedures that rule this test. The main difference between them remains in the waveform, in wich the load is applied, and in the failure criteria. This paper reports the influence from the waveform, haversine orsinusoidal, on the fatigue resistance of an asphalt mixture. In adition, through numerical simulation, it was evaluated ones found on sinusoidal tests.

Resumen: El fenómeno de fatiga como unos de los principales mecanismos de deterioro de las capas asfálticas. El ensayo de fatiga a flexión a cuatro puntos de apoyo es uno de los procedimientos más utilizados para determinar la resistencia a la fatiga de las mezclas asfálticas. Existen, a nivel internacional, diversas normas que estandarizan este tipo de ensayo, las cuales se diferencian básicamente por la forma de la onda de carga aplicada y por el criterio de rotura utilizado. Este artículo tiene como objetivo presentar los resultados de la influencia del tipo de onda de carga utilizada, haversine o sinusoidal, en la resistencia a la fatiga de una mezcla asfáltica, como también, la influencia de los modelos de fatiga obtenidos en la previsión de la rotura por fatiga de la capa asfáltica en una estructura de un pavimento flexible. Al final, se concluyó que la vida útil de la capa asfáltica estimada utilizando los modelos obtenidos en el ensayo con ondas con forma haversine fue 67 veces mayor que cuando estimada con los modelos de los ensayos realizados con carga sinusoidal.

Resumo O predador Brumoides foudrasii (Mulsant) (Coleoptera, Coccinellidae) tem sido encontrado naturalmente sobre plantas infestadas por cochonilhas. Neste estudo, a cochonilha listrada Ferrisia dasyliri (Cockerell) (Hemiptera, Pseudococcidae) e ovos de Anagasta kuehniella Zeller (Lepidoptera, Pyralidae) foram avaliados como dietas para o desenvolvimento e reprodução de B. foudrasii. Formas amaturos de B. foudrasii desenvolveram-se mais rapidamente quando alimentados com ovos de A. kuehniella do que quando alimentados com F. dasyliri. No entanto, a sobrevivência e longevidade de adultos de B. foudrasii não foram afetadas pelas dietas. A oviposição foi mais freqüente em B. foudrasii alimentadas com F. dasylirii (95%) do que aqueles alimentados com ovos de A. kuehniella (65%). Fêmeas de B. foudrasii alimentadas com F. dasylirii foram 2,5 vezes mais fecundas do que aquelas alimentados com ovos de A. kuehniella. Embora ambas as dietas possam ser consideradas apropriadas para B. foudrasii, ovos de A. kuehniella foram mais adequadas para o desenvolvimento de imaturos, enquanto F. dasylirii proporcionou mais recursos nutritivos para os parâmetros biológicos do adulto, tais como período de oviposição, viabilidade de ovos e fecundidade. Estes resultados sugerem que este predador pode ser potencialmente eficiente na regulação populacional da cochonilha F. dasylirii em campo.

Abstract The predator Brumoides foudrasii (Mulsant) (Coleoptera, Coccinellidae) has been naturally found in plants infested by mealybugs. In this study, the striped mealybug Ferrisia dasylirii (Cockerell) (Hemiptera, Pseudococcidae) and Anagasta kuehniella Zeller (Lepidoptera, Pyralidae) eggs were evaluated as diets for the development and reproduction of B. foudrasii. Brumoides foudrasii immatures developed faster when fed with A. kuehniella eggs than when fed with F. dasylirii. However, the survival and longevity of B. foudrasii adults were not affected by the diets. Oviposition was more frequent when B. foudrasii females were fed with F. dasylirii (95%) than those fed with A. kuehniella eggs (65%). Brumoides foudrasii females fed with F. dasylirii were 2.5 times more fecund than those fed with A. kuehniella eggs. Although both diets may be considered proper for B. foudrasii, A. kuehniella eggs were more suitable for immature development, while F. darsyrili provided more nutritious resources for adult biological parameters as oviposition period, egg viability and fecundity. These results suggests that this predator can play an important role in regulating populations of the stripped mealybug F. dasylirii in the field.

Resumo Neste trabalho foi determinada a concentração dos metais (Cd, Cr, Cu, Fe, Mn, Ni, Pb e Zn) na água do submédio Rio São Francisco para avaliar a influência da urbanização e da industrialização nas modificações ambientais do recurso hídrico. Todas as amostras foram analisadas usando o método IUPAC adaptado e processados em um espectrofotômetro de absorção atômica. As estações de amostragem localizadas próximas às áreas industriais sofreram influência da industrialização por apresentarem concentrações mais elevadas de Cd, Cr, Ni e Cu. Os demais locais amostrados apresentaram modificações com relação aos elementos traços de provável origem sedimentar como Fe, Zn e Pb. Houve aumento gradativo nas concentrações dos metais, de forma geral, no período de maior pluviosidade da rede hidrográfica. Em geral, com exceção do Zn e Mn, os elementos traços ultrapassaram o valor máximo permitido, estabelecido pela legislação nacional (CONAMA). O submédio Rio São Francisco tem sofrido interferência da urbanização e industrialização, por isso, é preciso que, programas de conscientização sejam estabelecidos, para controlar e amenizar problemas futuros.

Abstract In this study we determined the concentration of metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in the water lower São Francisco River basin, to evaluate the influence of urbanization and industrialization on environmental changes in the water resource. All samples were analyzed using the IUPAC adapted method and processed in an atomic absorption spectrophotometer. The sampling stations located near the industrial areas were influenced by industrialization because they presented higher concentrations of Cd, Cr, Ni and Cu. The other sampled locations showed changes with regard the trace elements probably originating in the soil, like Fe, Zn and Pb. There was a gradual increase in the concentrations of metals, in general, in the period of highest rainfall of the hydrographic network. Overall, except for Zn and Mn, the trace elements exceeded the maximum allowed value established by national legislation (CONAMA). Lower São Francisco River basin has suffered interference from urbanization and industrialization, so awareness programs should be developed so as to control and lessen future problems.

An uranyl complex [UO2(TFA)2(DMSO)3] (TFA=deprotonated trifluoroacetic acid; DMSO=dimethyl sulfoxide) has been successfully synthesized by reacting UO2(CH3COO)2·H2O with one equivalent of (CF3CO)2O and DMSO. The complex has been characterized by single-crystal X-ray diffraction, X-ray powder diffraction, elemental analysis, FT-IR spectroscopy, thermal analysis and absorption and emission spectroscopies. The spectroscopic properties of the material make it suitable for its application in the sensing and monitoring of uranyl in the PUREX process.

Resumo A resistência mecânica e a propriedade dielétrica de isoladores cerâmicos são características fundamentais para o suporte das redes de distribuição de energia elétrica. Porém, tanto a umidade quanto o teor de poluentes na atmosfera podem vir a ser prejudiciais e causar falhas na entrega de energia por elevação da sua corrente elétrica de fuga. O vidrado do isolador tem grande afinidade com a água resultante da interação da superfície do vidro com a atmosfera. No presente trabalho, foi realizada a deposição de filmes de nitreto de alumínio sobre o vidrado de amostras de isoladores elétricos cerâmicos, via plasma "magnetron sputtering" pulsado, de corrente contínua, e com uma mistura dos gases argônio e nitrogênio e de Ti sobre isoladores tipo pino para classes de tensão de 15 kV. A morfologia dos filmes e o desempenho dos isoladores foram medidos por MEV-FEG/EDS, AFM, máxima corrente de fuga RMS e grau de hidrofobicidade. O comportamento dos filmes depositados medido pelo grau de hidrofobicidade reduziu nas amostras de CM6 para CM4, com AlN, e de CM7 para CM3 quando foi depositado o Ti. A máxima corrente de fuga RMS medida nos isoladores sem e com filme nanométrico à base de Ti foi superior nos dispositivos sem a proteção, alcançando valores medidos de 5 mA e com desligamento do sistema computadorizado de medida (após 3 dias em Sauípe e 3 meses em Pituba) em consequência desta ter superado o intervalo de segurança de curto circuito estabelecido nos dispositivos eletrônicos de proteção (surtos superiores a 300 mA). Com a deposição dos filmes em 7 isoladores, foram verificadas alterações de comportamento em dois destes, com picos de máxima corrente de fuga atingindo 2,4 mA no campo. A maioria dos isoladores analisados teve como variações de correntes de fuga RMS, no período de medida, entre 0,2 e 2 mA, em condições adversas de clima (com chuva e diferentes velocidades de vento).

Abstract The mechanical strength and the dielectric properties of ceramic insulators are essential properties to support the electricity distribution networks. However, both the moisture and the pollutant content in the atmosphere may become harmful and cause failures in the power supply by increasing its electrical current leakage. The insulating glazing has high affinity with the resulting water from the interaction of the glass surface with atmosphere. In this study, the deposition of aluminum nitride films was carried out on the glazed samples of ceramic electrical insulators, via pulsed DC magnetron sputtering plasma, and with a mixture of argon and nitrogen gas and Ti on pin type insulators for 15 kV voltage class. The morphology of the films and the performance of insulators were measured by SEM-FEG/EDS, AFM, maximum RMS leakage current and degree of hydrophobicity. The performance of deposited films by the degree of hydrophobicity measured in samples reduced from CM6 to CM4 with AlN, and CM7 to CM3 with Ti layer. The maximum RMS leakage current measured with and without the insulating film based on nanometric Ti was higher in devices without the pr otection, reaching measured values of 5 mA and with shutdown of computerized measuring system (after 3 days in Sauípe and 3 months in Pituba) as a consequence of having overcome the short circuit withdrawal period laid down in software (surges exceeding 300 mA). With the deposition of the films in 7 insulators, changes in two of these, with peaks of maximum leakage current achieving 2.4 mA, in the field were observed. Most insulators analyzed had the variations in RMS leakage current between 0.2 and 2 mA in the measurement period, in adverse conditions of weather (rain and differ ent wind speeds).

Natural lignocellulosic fiber epicarp extracted from the babassu coconut (Orbignya speciosa) was chemically modified through reaction with molten maleic anhydride without solvent, with incorporation of 189.34 mg g-1 of carboxylic acid groups into the biopolymer structure. The success of this reaction was also confirmed by the presence of carboxylic acid bands at 1741 and 1164 cm-1 in the infrared spectrum. Identically, the same group is observed through 13C NMR CP/MAS in the solid state, via high field signals in the 167 pm region. Both the precursor and the immobilized maleated biopolymers presented nearly the same thermal stability and similar crystallinity to cellulose. However, the pendant carboxylic groups have the ability to remove copper with maximum sorption through a batchwise process at pH 6.0, as expected from the point of zero charge, determined to be 6.45. The sorption kinetic data were fitted to pseudo-first order, pseudo-second order, Elovich-chemisorption and intra-particle diffusion models and the equilibrium data were fitted to the Langmuir, the Freundlich and Tenkim isotherm models. Taking into account a statistical error function and determination coefficients, the data were fit to the pseudo-first and pseudo-second order kinetic and Langmuir isotherm models, with a maximum sorption capacity of copper ions of 55.09 mg g-1. This value suggests the application of this biopolymer with incorporated carboxylate groups as a favorable agent for copper removal from appropriate systems.

Na produção de componentes cerâmicos, além de se buscar propriedades especificas e superiores, também se busca produzir peças com dimensões que atendam aos requisitos do projeto. Um dos exemplos da importância do controle dimensional é a produção de cerâmicas do tipo piezoelétricas à base de titanato-zirconato de chumbo, aplicadas em transdutores hidroacústicos, cujo processamento não é trivial, sendo dispendioso e de risco ao manuseio (por causa da presença de chumbo), principalmente se a geometria especificada for hemisférica. Para a otimização do processamento (conformação e sinterização) destas cerâmicas pode-se utilizar outros insumos, como alumina, menos agressivo ao meio ambiente, maior disponibilidade, maior facilidade para processamento, de baixo risco ao manuseio, bem como, de baixo custo. Por esta razão, neste trabalho foram utilizadas duas composições à base de alumina, A (96,1% Al2O3, 3,0% SiO2, 0,9% MgO) e B (99,1% Al2O3, 0,9% MgO) e temperaturas de sinterização de 1550 ºC e 1650 ºC. O objetivo deste estudo foi produzir uma cerâmica com geometria hemisférica, de alta densidade, com controle dimensional relativo, por meio de prensagem uniaxial para conformação. Observou-se que a melhor relação entre o controle dimensional e a alta densificação foi obtida com a composição A e sinterização a 1550 ºC, em presença de fase líquida pela adição de SiO2. Apesar de os resultados para a composição B com sinterização a 1650 ºC terem sido aparentemente melhores, esta composição teve sua densificação comprometida e muito abaixo da esperada. Com os resultados obtidos da relação entre controle dimensional e processamento, podem-se aplicar algumas das etapas utilizadas para a produção de cerâmicas à base de PZT com alta densidade, por uma técnica de conformação simples, e geometria complexa (hemisférica), exigida como requisito de projeto de transdutores hidroacústicos.

In the production of ceramic components, specific and better properties are required to produce pieces according to the project. One example of the importance of the dimensional control is the production of piezoelectric ceramic for hydro-acoustic transducers. Its processing is not trivial, is expensive and risky to handle (due to the presence of lead), particularly for hemispheric shape. For the optimization of the processing (mechanical consolidation and sintering) of these ceramics, other materials may be used, such as alumina, less aggressive to the environment, with higher availability, easier processing, low risk for handling, as well as low cost. In this work two compositions based on alumina were used, A (96.1% Al2O3, 3.0% SiO2, 0.9% MgO) and B (99.1% Al2O3, 0.9% MgO), and two sintering temperatures, 1550 °C and 1650 °C. The objective of this study was to produce a ceramic with complex hemispherical geometry, high density and relative dimensional control, consolidated by dry pressing. It was observed that the best ratio of dimensional control and high densification was achieved with the A composition and sintering temperature 1550 °C, by liquid phase formed by adding SiO2. Although the results for composition B sintered at 1650 °C were apparently the best, this composition had densification much lower than expected. With the results of the relationship between dimensional control and processing can carry some of the steps used for the production of PZT-based ceramics with high density, by a simple mechanical consolidation and complex geometry (hemispherical) required for hydro-acoustic transducers.