Resumen Introducción: La hipótesis del enemigo postula que las características de la agalla protegen al agallero contra los enemigos naturales. Las agallas muestran una gran variedad de tamaños, colores y adornos, que varían incluso de forma intraespecífica. Sin embargo, los agalleros son objetivos de varios organismos que los atacan directa o indirectamente. En este contexto, considerar solo una característica para investigar la estructura de la agalla actúando contra un solo gremio de enemigos puede ocultar una comprensión de las interacciones a nivel comunitario. Objetivos: Para investigar las ideas presentadas usamos las agallas conspicuas inducidas por Palaeomystella oligophaga Becker y Adamski 2008 (Lepidoptera) en Macairea radula (Bonpl.) (Meslastomataceae) como sistema modelo. Describimos este sistema a través de la categorización de los diferentes gremios enemigos presentes en la comunidad. Los identificamos al nivel taxonómico más bajo posible y determinamos el tipo de interacción responsable de la muerte de los agalleros. Teniendo en cuenta la hipótesis del enemigo y la selección de características secundarias, también buscamos determinar cuáles de las múltiples caracteristicas de la agalla influyen en el éxito de supervivencia de los agalleros en un contexto de enemigos múltiples. Métodos: Inspeccionamos las agallas y caracterizamos los gremios enemigos que afectan al agallero y las tasas de mortalidad producidas por cada uno de ellos. Luego, probamos si las distintas caracteristicas de las agallas medidas (grosor del parénquima, color, proyecciones) promueven la supervivencia de los agalleros con respecto a cada enemigo. Resultados: La mortalidad indirecta inducida por los cecidofagos fue del 47.3 %, superior a la causada por los parasitoides y los depredadores (31.5 %). Apesar de la complejidad estructural de la agalla, los agalleros vivos mostraron la menor presencia (21.2 %). El grosor del parénquima se relacionó negativamente con los parasitoides de Calliephialtes, los cecidófagos de Gelechiidae y la depredación. Conclusiones: Demostramos que los ataques a los tejidos biliares por cecidófagos representaron la mayor amenaza para la supervivencia de P. oligophaga. Esto es interesante porque, de acuerdo con la hipótesis del enemigo, la estructura de las agallas debería proporcionar protección para los insectos agalleros en lugar de atraer a los insectos que se alimentan de la agalla misma. Sin embargo, también demostramos que el grosor del parénquima puede estar relacionado negativamente con algunos organismos, especialmente los enemigos directos. Otras caracteristicas hipotéticas como defensivas (por ejemplo, proyecciones, coloración) pueden simplemente no desempeñar ningún papel.

Abstract Introduction: The enemy hypothesis postulates that gall traits protect galling insects against natural enemies. Galls show a huge range of sizes, colors and ornaments, which vary even intraspecifically. However, galling insects are targets of various organisms that attack them directly or indirectly. In this context, to consider only one gall trait to investigate gall structure acting against only one guild of enemies can conceal an understanding of the community-level interactions. Objective: Herein, we take these ideas into consideration to investigate the conspicuous galls induced by Palaeomystella oligophaga Becker and Adamski 2008 (Lepidoptera) on Macairea radula (Bonpl.) (Melastomataceae) as a model system. We characterize this system through categorization of the different enemy guilds present in the community. We identified them to the lowest taxonomic level possible and determined the kind of interaction responsible for galling insects’ deaths. Considering the enemy hypothesis and the selection of secondary characteristics, we also aimed to determine which of the multiple gall traits influence the survival success of galling insects in a multi-enemy context. Methods: We inspected galls and characterized the enemy guilds affecting the galling insect and the mortality rates produced by each one of them. Next, we tested whether the distinct gall traits measured (parenchyma thickness, color, projections) promote galling insect survival with respect to each enemy. Results: The mortality induced by indirect enemies (organisms that interact with gall tissues and can interact secondarily with galling insect) was 47.3 %, being higher than that caused by parasitoids and predators (31.5 %). Despite the gall’s structural complexity, live galling insects showed the smallest occurrence (21.2 %). Parenchyma thickness was negatively related to Calliephialtes parasitoids, Gelechiidae cecidophages and predation signals. Conclusions: We demonstrated that the attacks to gall tissues by the cecidophages represented the highest threat to P. oligophaga survival, being higher than the mortality caused by direct enemies. That is, the gall traits were not as efficient as supposed to protect the galling insect from the attack of natural enemies. Nevertheless, we also demonstrated that parenchyma thickness can be negatively related to some organisms, especially direct enemies. Other traits hypothesized as defensive (e.g. projections, coloration) may simply play no role.

Resumo O porcelanato é um tipo de placa cerâmica de revestimento que vem se destacando atualmente por apresentar boas propriedades estéticas, como a superfície decorada, e mecânicas, como a baixa absorção de água e elevada resistência mecânica e ao ataque químico. As matérias-primas utilizadas para a produção de porcelanato são principalmente a argila e o feldspato. O feldspato é uma das matérias-primas responsáveis pela sinterização durante a queima e auxilia no desenvolvimento de baixa porosidade e elevada resistência ao desgaste da peça cerâmica. Porém, o Brasil apresenta reservas de feldspato em regiões distantes dos centros produtores, fato que encarece a produção deste produto. Dessa forma surge como alternativa a utilização de nefelina para substituir o feldspato, total ou parcialmente, pois este mineral apresenta características bastante similares. Para verificar a influência de tal substituição nas propriedades do porcelanato, inicialmente foi necessário realizar o estudo das propriedades reológicas e físicas da suspensão utilizada na produção. Os resultados encontrados mostraram que a viscosidade da suspensão tende a aumentar com a adição de nefelina, assim como a densidade aparente da peça após a queima.

Abstract The porcelain is a type of ceramic tile which has been contrasted for its good aesthetical, such as decorated surface, and mechanical properties, such as low water absorption and high mechanical and chemical attack resistance. The raw materials used for porcelain tiles production are mainly clay and feldspar. Feldspar is one of the raw materials responsible for the sintering during firing and it helps on the development of low porosity and high wear resistance of the ceramic piece. However, Brazil presents feldspar sources in regions distant from production centers, leading to higher cost for the porcelain tiles production. Thus, nepheline is thought as an alternative to substitute feldspar, totally or partially, since this mineral presents very similar characteristics. In order to verify the influence of this substitution to the properties of the porcelain tiles, it was necessary initially to study the influence of nepheline addition in both rheological and physical properties of the suspension. The results showed that the viscosity of the suspension increases with the addition of nepheline, as well as the apparent density of the fired piece.

São investigados o comportamento estrutural e a resistência última à punção de ligações laje-pilar de regiões internas das lajes lisas, com um furo adjacente ao pilar, e com ou sem transferência de momento fletor da laje ao pilar. As principais variáveis foram: a existência ou não de furo, a taxa e a distribuição da armadura de flexão, a direção e o sentido do momento transferido e a excentricidade de carga (relação M(momento transferido ao pilar)/V(força cortante)) na ligação, igual a 0,50 m ou 0,25 m. Foram ensaiadas 7 (sete) ligações internas laje-pilar e analisados os resultados das cargas últimas, fissuração, deslocamento vertical, deformações das armaduras de flexão e do concreto. A existência de furo adjacente ao menor lado do pilar, a taxa e a distribuição da armadura de flexão, a variação da relação Mu/Vu em função do carregamento, e, por conseguinte, da excentricidade, influenciaram o comportamento e a carga de ruptura das lajes. Os resultados experimentais foram comparados com os estimados pelas normas: CEB-FIP/MC1990 [7], EC2/2004 [12], ACI-318:2011 [1] e NBR 6118:2007 [5]. O ACI [1] e o EC2 [12] apresentaram estimativas mais conservadoras, embora tenham apresentado algumas estimativas contra a segurança. A NBR 6118:2007 [5], apesar de baseada em parte no EC2 [12], apresentou estimativas menos conservadoras e com um número maior de estimativas contra a segurança.

The structural behavior and the ultimate punching shear resistance of internal reinforced concrete flat slab-column connections, with one hole adjacent to the column, with or without flexural moment transfer of the slab to the column was investigated. Main variables were: the existence whether or not hole, flexural reinforcement layout and ratio, the direction and sense of the moment transferred and the eccentricity of the load (M (moment transferred to column) / V (shear)) ratio at the connection - 0,50 m or 0,25 m. Seven internal slab-column joining were tested and ultimate loads, cracking, deflections, concrete and reinforcement strains were analyzed. The existence of hole adjacent to the smaller column dimension, the hole dimension, flexural reinforcement rate and placing, the variation of relation Mu/Vu in function of the load, and, than, of eccentricity of the load, influenced the slabs behavior and rupture load. Test results were compared with the estimations from CEB-FIP/MC1990 [7], EC2/2004 [12], ACI-318:2011 [1] and NBR 6118:2007 [5]. ACI [1] and EC2 [12] presented most conservative estimates, although have presented some non conservative estimates. Brazilian NBR [5], even though being partly based in EC2 [12], presented smaller conservative estimates and more non conservative estimates. A modification on all codes is proposed for taking in account the moment caused by the eccentricity at the critical perimeter for slabs with holes.

Filtering hydrocyclone is a device that was developed and patented by the Particulate System Research Group at the Federal University of Uberlandia. This equipment consists of a hydrocyclone whose conical section is replaced by a conical filtering wall. Thus, during the operation of these devices, besides the underflow and overflow streams, there is another stream of liquid, resulting from the filtrate produced in the porous cone. In the present work, the influence of some geometric variables of a filtering hydrocyclone was analyzed by an experimental and CFD study. The geometric variables analyzed were underflow orifice diameter (D U) and vortex finder length (ℓ). Data from a conventional hydrocyclone of the same configuration were also obtained. The results indicated that the performance of hydrocyclones is significantly influenced by the conical filtering wall. The incorporation of the filtering medium decreased the Euler numbers and increased the total efficiency of the hydrocyclones. Depending on the specific functions of the separator (as a classifier or concentrator) the best values of D U and ℓ were also found for the filtering hydrocyclone.