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Silicone rubber (SR) and ethylene-propylene-diene monomer (EPDM) are widely-used polymers as housing for high voltage insulators. In this work, SR/EPDM/clay nanocomposites were obtained by two-roll mill mixing for outdoor polymeric insulators. Morphology, dielectric properties, dielectric breakdown strength (DBS), and surface and volume resistivity of different weight contents of nanoclay (Cloisite 15A) incorporated in SR, EPDM, and SR/EPDM hybrid nanocomposites were characterized. In addition, the distribution of breakdown voltages was fit to the distribution of Weibull and estimated the scale and shape parameters. The polar groups of the clay particles enhanced the polarization capability of the nanocomposites. Moreover, DBS results showed an enhancement of the dielectric strength proportional to clay content. Finally, the surface and volume resistance of all nanocomposites decreases but maintains very high electrical resistance. The experimental data presented in this study will be useful for designing and manufacturing the outdoor insulators. Fil: Bazli, Leila. Nano and Smart Polymers Center of Excellence. Iran Polymer & Petrochemical Institute; Irán Fil: Eskandarinezhad, Sara. Yazd University. Department of Mining and Metallurgy; Irán Fil: Kakur, Naresh. Indian Institute of Technology Madras. Department of Aerospace Engineering; India Fil: Ramachandran, Velmurugan. Indian Institute of Technology Madras. Department of Aerospace Engineering; India Fil: Bacigalupe, Alejandro. Instituto Nacional de Tecnología Industrial. Centro de Materiales Avanzados (INTI); Argentina Fil: Mansilla, Marcela. Instituto Nacional de Tecnología Industrial. Centro de Materiales Avanzados (INTI); Argentina Fil: Escobar, Mariano. Instituto Nacional de Tecnología Industrial. Centro de Materiales Avanzados (INTI); Argentina

In recent years it has been discovered that some common use medicines, such as ibuprofen and other nonsteroidal anti-inflammatory drugs, are found in water sources in concentrations that have the potential to affect aquatic organisms. On the other hand, waste used tires are a massive problem for the environment due to the leaching of toxic compounds to soils and water. Also, the exposition to environmental conditions can make them sources of vectors like mosquitoes. In this work, three activated carbon (AC) catalysts derived from waste tire rubber, titanium dioxide and silver were synthesized using the sol–gel method. Morphological characterizations such as SEM and TEM were performed in which, the agglomeration of titanium particles and silver crystals on the surface of the AC is evident. In the XRD analysis, the presence of elemental silver nanoparticles was detected. In the diffuse reflectance spectroscopy analysis, the decrease in the titanium band gap, as well as activity in the visible spectrum, was observed. The photocatalytic tests were performed at pH 3 and 7 in the presence of UV/Vis radiation. These tests show that there are differences between the catalyst in both, UV and visible regions. Adsorption is a major phenomenon for the removal of ibuprofen, followed by photolytic decomposition. In visible spectra, the catalysts show a good performance for the removal of ibuprofen.

RESUMEN: La gestión estratégica de la información científicotecnológica resulta cada vez más importante para innovar en el desarrollo de nuevos productos y procesos. El trabajo investigativo en diferentes áreas como por ejemplo la ciencia de los materiales, en conjunto con la industria, es la fórmula perfecta para descubrir un producto, mejorar uno existente y encontrarle aplicaciones alternativas. Este artículo presenta una revisión de la literatura acerca de las principales características y tendencias en la utilización de microesferas poliméricas expandibles, incluyendo aplicaciones derivadas tanto de estudios terminados como de líneas de investigación en desarrollo. Algunas aplicaciones destacadas son: la modificación superficial de algunos tipos de materiales como el cuero, aislamiento térmico, fabricación de piezas para automóviles y fabricación de prótesis maxilofaciales. Entre las aplicaciones potenciales que vale la pena resaltar están: la fabricación de materiales con aislamiento acústico y como componente en materiales, tales como los elastómeros para la obtención de suelas livianas y cómodas. Palabras clave: Materiales poliméricos; Expancel; compuesto de caucho; suelas y liviandad. ABSTRACT: The strategic management of the scientific and technological information is increasingly more important to innovate the development of new products and processes. The research work in different areas such as materials science along with industries, is the perfect formula to find a product, improve an existing one and so find alternative applications to it. This paper presents a review of the literature on the main features and trends in the use of the expandable polymeric microspheres, including applications derived from completed studies and developing research lines. Some important applications are: the surface modification on some materials such as, leather, thermal insulation, car parts and maxillofacial prosthesis manufacture. Potential applications that are worth noting are: the manufacture of materials with sound insulation, and as a component in elastomers for the production of lightweight and comfortable soles. Keywords: expandible polymeric microspheres; Expancel; rubber compound; soles and lightness.

Fil: Córdoba, Lorena Isabel. Pontificia Universidad Católica Argentina. Facultad de Ciencias Sociales. Instituto de Investigaciones; Argentina Abstract: The “rubber boom” played a decisive role in the integration of the Amazon rainforest into the global economy. Between 1870 and 1920, most Amazonian countries eagerly engaged in the rubber trade: first, Brazil, accounting for nearly 80–90 percent of the world market, followed by Bolivia and Peru, with 5–10 percent, and, finally, by Colombia and Venezuela, with a lower production.1 This article discusses the commodification of rubber in Bolivia from 1880 until its decline in the 1910s. It poses the question of how social perceptions of rubber as a wild, inexhaustible natural resource grounded, and affected, the structure of its exploitation.

The evaluation of forest composition is a very important stage of forest management. This evaluation is done through forest inventories. The objective of this work is to present the results of a 100% forest inventory make in areas of forest exploitation of small farmers under logging management, located in the municipality of Senador Guiomard, in the state of Acre, in the Brazilian Amazon. The inventoried area (206.8 ha), in which all the trees with DBH  50.0 cm were measured, revealed a total number of trees (NT) of 3,518, abundance (AB) of 17.01 trees ha-1, total volume (VT) of 21,667.41 m3, volume per hectare (V) of 104.77 m3 ha-1, total basal area (ABsT) of 1,413.77 m2 and basal area per hectare (ABs) of 6.84 m2 ha-1. A total of 204 species belonging to 136 genera and 43 botanical families were recognized in the field. The five species of highest Index of Importance of Species (IND) were: Brazil nut (Bertholletia excelsa Bonpl.), Tauari (Couratari macrosperma A.C. Sm.), Cumaru-cetim (Apuleia molaris Spruce ex Benth.), Rubber tree (Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg.) and Cumaru-ferro (Dipteryx odorata (Aubl.) Willd.). The sum of the IND of these five represents a third (33.6%) of the total IND (all species). Most of the 20 species with the highest IND are loggers of commercial use and represents for about 60% of the total IND. This study showed a significant concentration of the dendrometric elements, that is, few species unit most of the adult trees and, consequently, most of the timber volume. Entre as etapas fundamentais do manejo florestal está a avaliação da composição da floresta. Essa avaliação é feita por meio de inventários florestais. Este trabalho tem como objetivo apresentar resultados de um inventário florestal a 100% realizado em talhões de colheita de pequenas áreas sob manejo florestal madeireiro, localizadas em Senador Guiomard-AC. A área inventariada, de 206,8 ha, em que foram abordadas todas as árvores com DAP  50,0 cm, revelou um número total de árvores (NT) de 3.518, abundância (AB) de 17,01 árvores ha-1, volume total (VT) de 21.667,41 m3, volume por hectare (V) de 104,77 m3 ha-1, área basal total (ABsT) de 1.413,77 m2 e área basal por hectare (ABs) de 6,84 m2 ha-1. Foram reconhecidas 204 espécies, pertencentes a 136 gêneros e a 43 famílias botânicas. As cinco espécies de maior Índice de Importância da Espécie (IND) foram: Castanheira (Bertholletia excelsa Bonpl.), Tauari (Couratari macrosperma A.C. Sm.), Cumaru-cetim (Apuleia molaris Spruce ex Benth.), Seringueira (Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg.) e Cumaru-ferro (Dipteryx odorata (Aubl.) Willd.). Estas cinco espécies representaram um terço (33,6%) do IND total. A maioria das 20 espécies com maior IND são madeireiras de uso comercial e responderam por cerca de 60% do IND total. Os resultados mostraram expressiva concentração dos elementos dendrométricos, ou seja, poucas espécies reúnem a maior parte das árvores adultas e, conseqüentemente, a maior parte do volume madeireiro. Made available in DSpace on 2019-04-17T01:12:32Z (GMT). No. of bitstreams: 1 26792.pdf: 762605 bytes, checksum: 4ced4b598f127d0f9cc230bc20be15e0 (MD5) Previous issue date: 2019

RESUMEN: Se estudió la variación de las propiedades mecánicas bajo compresión uniaxial y el desgaste abrasivo en la sección transversal de piezas gruesas de caucho acrilonitrilo (NBR) reforzadas con negro de humo, teniendo en consideración que en este tipo de piezas las propiedades obtenidas durante la vulcanización no son homogéneas, debido a la baja difusividad térmica de los cauchos. Se realizaron ensayos de desgaste abrasivo en seco, buscando identificar la relación entre la resistencia al desgaste abrasivo y las propiedades mecánicas en compresión, como el módulo elástico y la dureza. Se evaluaron muestras en estado de entrega tras el proceso de vulcanización, luego expuestas al ambiente durante tres meses y, posteriormente, envejecidas en una cámara UV. El envejecimiento ambiental rigidiza los materiales estudiados, pero disminuye la resistencia al desgaste del material proveniente del núcleo de las piezas. El envejecimiento UV disminuyó el módulo elástico, pero su efecto sobre la resistencia al desgaste depende del estado de envejecimiento previo. La dureza no presentó una relación directa ni con el módulo elástico ni con la resistencia al desgaste, por lo cual no puede usarse como propiedad para la selección de cauchos NBR sometidos a desgaste abrasivo. La información obtenida permite generar criterios para el diseño de componentes basados en este tipo de cauchos. ABSTRACT: In this work the mechanical properties variability under uniaxial compression and the abrasive wear through the cross section of thick-piece carbon-black reinforced acrylonitrile rubber (NBR) parts, was studied. It has to take into account that in these type of pieces, the vulcanized rubber properties heterogeneity causes a variability effect, due to its low thermal diffusivity. Abrasive wear tests under dry conditions were carried out, seeking to identify the relationship between abrasive wear resistance and mechanical properties under uniaxial compression, such as hardness and elastic modulus. The samples in delivery state were evaluated after the vulcanization process, then environmentally exposed during three months and finally UV aged. Environmental aging stiffens the NBR, but the samples wear resistance from the cross sectional area center, is diminished. Their elastic modulus decreased with the UV aging, but its effect on the wear resistance depends from the previous environmental aging. Their hardness did not show a relationship neither with the elastic modulus nor with the wear resistance; therefore, it should not be used as a property to select the NBR rubbers, subject to wear resistance. The information obtained allows to generate design criteria for nitrile rubber-based parts. COL0069779 COL0012659

Warm Mix Asphalt (WMA) refers to technologies that reduce manufacturing and compaction temperatures of asphalt mixtures allowing lower energy consumption and reducing greenhouse gas emissions from asphalt plants. These benefits, combined with the effective reuse of a solid waste product, make asphalt rubber (AR) mixtures with WMA additives an excellent environmentally-friendly material for road construction. The effect of WMA additives on rubberized mixtures has not yet been established in detail and the lower mixing/compaction temperatures of these mixtures may result in insufficient compaction. In this sense, the present study uses a series of laboratory tests to evaluate the volumetric characteristics and compactability of AR mixtures with organic additives when production/compaction temperatures are decreased. The results of this study indicate that the additives selected can decrease the mixing/compaction temperatures without compromising the volumetric characteristics and compactability., Las mezclas semicalientes permiten reducir las temperaturas de fabricación y compactación de las mezclas asfálticas y disminuir el consumo de energía y emisión de gases de efecto invernadero en las plantas asfálticas. Estos beneficios, junto con la reutilización efectiva de un producto de desecho, harían de las mezclas con caucho y aditivos de mezclas semicalientes un excelente material para la construcción de carreteras respetuoso con el medio ambiente. En esta investigación se estudia, a través de una serie de ensayos de laboratorio, las características volumétricas y de compactabilidad de las mezclas con caucho y aditivos orgánicos de mezclas semicalientes, ya que se desconoce el efecto de estos aditivos al disminuir las temperaturas de producción/compactación, pudiendo tener lugar una compactación insuficiente. Los resultados han indicado que los aditivos seleccionados pueden disminuir las temperaturas de producción/compactación de las mezclas sin comprometer las características volumétricas y la compactabilidad.

In recent years, the railway sector has focused on more sustainable constructive techniques and more durable solutions such as the inclusion of bituminous sub-ballast in order to reduce track degradation whilst improving its quality. The use of bituminous layer in railways tracks is regarded as an appropriate solution for improving the strength of the section. In comparison with traditional granular sub-ballast, these materials allow for both an increase in bearing capacity and greater protection of the substructure. However, the fact that these materials are manufactured at a temperature of 160°C means that their application can incur significant construction costs, along with a rise in pollution and energy consumption. In this regard, there is a need for the use of new techniques to produce asphalt, such as the reuse of waste materials or manufacturing with low-temperature technology, both of which allow for lower energy expenditure without changing its in-service mechanical performance, as well as reducing the general costs of this layer. In this context, this thesis therefore aims to, on the one hand, study the possibility of using sustainable bituminous sub-ballast manufactured from waste materials such as crumb rubber, which is recycled rubber produced from scrap tires and reclaimed asphalt pavement (RAP) from road pavement at the end of their service life. A further aim is to study the possibility of using WMA manufactured at lower temperatures, as bituminous sub-ballast. To this end, this thesis is focused on evaluating the mechanical behaviour of bituminous materials (under both routine and adverse temperatures) in comparison with that presented by conventional sub-ballast. In particular, performance is examined with respect to the main requirements that need to be met by these materials (resistance to plastic and punching deformations, bearing capacity, stress dissipation, cracking resistance, and waterproof properties) for their use in railway tracks. The results demonstrated that all the sustainable solutions studied, offer a suitable performance as subballast for railways tracks from a mechanical behaviour point of view. In addition, they can offer advantages such as reducing greenhouse emissions, fuel consumption and waste as in the case of HWMA 100% RAP. furthermore, the use of rubberized bituminous mixtures (DRA and WRA) make more durable sub-ballast layer, at the same time that allow for waste recovery. Finally, the use of WMA, despite its performances was slightly lower respect the others solutions studied, achieved acceptable results for its use as a subballast layer. Moreover, it is a solution that guarantees to reduce pollution and energy consumption thanks to its ability to reduce mixing and compaction temperatures., Tesis Univ. Granada. Programa Oficial de Doctorado en: Ingeniería Civil

El trazado de la frontera común entre países amazónicos se reconfigura en la época republicana con alguna dificultad en vista de la lejanía de estas regiones. Esta reconfiguración se ve movida por intereses privados de agricultores, exportadores y comerciantes, de los cuales el más connotado para la frontera común entre Perú, Colombia y Brasil es la Casa Arana. El autor repasa el caso de la expoliación de los indígenas de ese eje geográfico por parte de dicha compañía en centros como La Pedrera, El Encanto y La Chorrera, y relata las vivencias de una indígena uitoto al respecto. La guerra entre Colombia y el Perú es analizada en el marco de esta reconfiguración y del contexto de la geopolítica del momento. En la parte final se propone la necesidad de una agenda de justicia y reparación de los grupos indígenas objeto de este genocidio. The border shared by the countries of the Amazon was reset in the republican period not without some difficulty due to its remoteness. Such reconfiguration was motivated by the private interests of farmers, exporters and businessmen, of which the most important one in the common border between Peru, Colombia and Brazil was the Casa Arana. The author reviews the case of the pillaging of indigenous groups in that geographical axis carried out by such company in places like La Pedrera, El Encanto and La Chorrera, and describes the related experiences of a uitoto woman. The war between Colombia and Peru is thus analysed from the perspective of this reconfiguration and the geopolitical context at the time. The final section highlights the need for an agenda for the justice and reparation of the indigenous groups that were victims of this genocide. O traçado da fronteira comum entre países amazônicos reconfigura-se na época republicana com certa dificuldade à vista do longínquo destas regiões. Esta reconfiguração vê-se movimentada por interesses privados de agricultores, exportadores e comerciantes, dos quais o mais distinto na fronteira comum entre o Peru, a Colômbia e o Brasil é a Casa Arana. O autor repassa o caso da espoliação dos indígenas desse eixo geográfico por parte de tal companhia em centros como La Pedrera, El Encanto e La Chorrera e relata as vivências de uma indígena Uitoto ao respeito. A guerra entre a Colômbia e o Peru é analisada no marco desta reconfiguração e do contexto da geopolítica do momento. Na parte final propõe a necessidade de uma agenda de justiça e reparação para os grupos indígenas objeto de este genocídio.

RESUMEN: Este trabajo presenta un estudio exploratorio que usa la metodología OWAS (Ovako Working Posture Analysing System, por sus siglas en inglés) para analizar las posturas de heveicultores y operarios de la industria del caucho durante sus actividades laborales. El estudio se realizó en pequeñas plantaciones de una asociación de cultivadores de caucho en Tarazá, y en cinco pequeñas empresas de Medellín e Itagüí, en Antioquia-Colombia. Se analizaron los procesos in-situ, tomando registros mediante videos para posteriormente efectuar un análisis de los movimientos. Se encontró que los mayores riesgos ergonómicos para los heveicultores y los operarios de pequeñas y medianas industrias de caucho son la generación de trastornos musculoesqueléticos (TME) en la columna vertebral y la Back, con un nivel de riesgo 4. Se encontró también que el sangrado de los árboles, la recolección del látex, el mezclado en molino abierto de rodillos y la manipulación de moldes fueron las cuatro actividades en las cuales se presentan los principales riesgos de postura. Al final del trabajo se proponen recomendaciones para evaluar y reducir los riesgos de postura en pequeñas empresas de la cadena productiva del caucho natural. Se identificó que la reducción de los riesgos de postura in la cadena productiva del caucho natural requiere diseñar e implementar planes que consideren la cultura organizacional y factores socioeconómicos y sociodemográficos de los cultivadores de caucho natural y pequeñas industrias fabricantes de artículos en caucho, además de la utilización de algunas herramientas que reducen la manipulación de cargas pesadas. Palabras clave: Evaluación ergonómica, industria del caucho natural, OWAS, postura. ABSTRACT: This exploratory study used OWAS (Ovako Working Posture Analysing System) to analyze the working postures of natural rubber tappers and rubber industry workers. A community of natural rubber farmers of Tarazá and five small companies of Medellín and Itagüí, all of them allocated in Antioquia-Colombia, participated in this study. Processes were analyzed in-situ and videotapes of activities were recorded for carrying out a movement study. For an overall distribution of trunk postures, OWAS identified that a bent and twisted trunk posture which fell into action category 4, was the major poor posture for rubber tappers and rubber industry workers. This study also identified that latex tapping, latex collection, mixing in two roll mills and metallic molds operation were the four activities in which the major working posture risks were observed. It was found that reduction of posture risks in natural rubber production chain requires designing and implementing plans considering organizational culture, socio-economic and sociodemographic factors of natural rubber farmers and small rubber manufacturing industries, besides the use of some useful tools that reduce the handling of heavy loads. Keywords: Ergonomic assessment, natural rubber industry, OWAS, posture.

This study evaluates the influence of recycled rubber (RR) with a specific particle size in the properties of blends, blended recycled polypropylene/polyethylene (RPP) and RR (RPP/RR) -- The proportions of RPP/RR employed to obtain the blends were as follows: 90/10 (PP90), 75/25 (PP75), 60/40 (PP60) and 45/55 (PP45) -- The particle size of the RR employed was 850 µm -- The properties of the blends were evaluated by rheometric, thermogravimetric (TGA), differential scanning calorimetric (DSC), scanning electronic microscopy (SEM), density, melt flow index and tensile analysis -- The maximum torque increased with the RPP content -- By DSC analysis, it was observed that the RPP exhibited two melting temperatures, the first corresponded to low density polyethylene (LDPE) and the second to polypropylene (PP) -- Furthermore, the RR affected the crystallinity of the RPP -- By using SEM and TGA analyses, it was determined that the RPP as well as RR contained fillers -- The blend densities were higher than those of RPP -- The melt flow index exhibited a trend with the amount of RR.PACS: 61.25.hk, 83.80.Va, 81.05.Lg, Este estudio evalúa la influencia de caucho reciclado (RR) con un tamaño de partícula específico en las propiedades de mezclas, mezclas de polipropileno reciclado/polietileno (RPP) y RR (RPP/RR) -- Las proporciones de RPP/RR para obtener los compósitos fueron como sigue: 90/10 (PP90), 75/25 (PP75), 60/40 (PP60) and 45/55 (PP45) -- El tamaño de partícula empleado del RR fue 850 µm -- Las propiedades de las mezclas, fueron evaluadas por análisis reométrico, termogravimétrico (TGA), calorimetría diferencial de barrido (DSC), microscopia de barrido electrónica (SEM), densidad, índice de fluidez y ténsil -- El torque máximo incrementó con el contenido de RPP -- Por análisis DSC se observó que el RPP exhibió dos temperaturas de fusión, la primera correspondió al polietileno de baja densidad (LDPE) y la segunda al polipropileno (PP) -- Además, el RR afectó la cristalinidad del RPP -- Por análisis de SEM y TGA, se determinó que el RR y el RPP contenían rellenos -- Las densidades de las mezclas fueron más altas que la del RPP -- El índice de fluidez exhibió una tendencia con la cantidad de RR.PACS: 61.25.hk, 83.80.Va, 81.05.Lg

Anurans are predators of a great diversity of invertebrates, but studies on agroecosystems are very scarce. Herein we described the diet composition of seven species of terrestrial anurans captured in three different agroecosystems (corn, soybean and rubber tree) and in forest remnants of the Northwestern region of São Paulo state, Brazil. Ten prey categories were identified in the stomachs of 80 specimens belonging to the families Bufonidae, Leptodactylidae and Microhylidae. Hymenoptera (Formicidae) was consumed by all species. Coleoptera was the most frequent item, consumed by six of the even species followed by Araneae and Isoptera. Isoptera was the most abundant item followed by Formicidae, Coleoptera and Araneae. Adults and juveniles of Physalaemus nattereri, the most abundant species in our study, consumed Formicidae and Isoptera more than other food items and there is not a significant difference in the abundance of consumed prey items between the age categories. In summary, the majority of the studied species can be considered generalists predators and, probably, consumed the prey items available in the environment. The most abundant species found in our study can be considered here as having a specialized diet, by consuming social insects in great frequency. Published online on 12 August 2015.

Proyectos Confidencial (Riunet)

Hevea brasiliensis is a native species of the Amazon Basin of South America and the primary source of natural rubber worldwide. Due to the occurrence of South American Leaf Blight disease in this area, rubber plantations have been extended to suboptimal regions. Rubber tree breeding is time-consuming and expensive, but molecular markers can serve as a tool for early evaluation, thus reducing time and costs. In this work, we constructed six different cDNA libraries with the aim of developing gene-targeted molecular markers for the rubber tree. A total of 8,263 reads were assembled, generating 5,025 unigenes that were analyzed; 912 expressed sequence tags (ESTs) represented new transcripts, and two sequences were highly up-regulated by cold stress. These unigenes were scanned for microsatellite (SSR) regions and single nucleotide polymorphisms (SNPs). In total, 169 novel EST-SSR markers were developed; 138 loci were polymorphic in the rubber tree, and 98 % presented transferability to six other Hevea species. Locus duplication was observed in H. brasiliensis and other species. Additionally, 43 SNP markers in 13 sequences that showed similarity to proteins involved in stress response, latex biosynthesis and developmental processes were characterized. cDNA libraries are a rich source of SSR and SNP markers and enable the identification of new transcripts. The new markers developed here will be a valuable resource for linkage mapping, QTL identification and other studies in the rubber tree and can also be used to evaluate the genetic variability of other Hevea species, which are valuable assets in rubber tree breeding. Electronic supplementary material The online version of this article (doi:10.1007/s11032-014-0095-2) contains supplementary material, which is available to authorized users.

El objetivo del presente trabajo fue obtener las normas preli-minares de diagnóstico y recomendación integral DRIS para el cultivo de caucho clon FX3864 (Hevea brasiliensis) bajo condiciones de la altillanura colombiana para los elementos N, P, K, Ca, Mg, Na, S, Fe, Cu, Zn y B, para ello se tomaron 77 muestras de tejido foliar de plantaciones comerciales con edades entre 10 y 12 años. Para la selección de las rela-ciones que se convirtieron en normas se utilizó el método de mayor relación entre varianzas entre la población de baja productividad sobre la de alta productividad. De las 132 re-laciones posibles se seleccionaron 66, destacándose relacio-nes como P/N, N/K, NXCa. El nutriente más limitante es el K seguido del N por defecto y el Ca seguido del S por exceso. The present study aimed to establish the preliminary diagno-sis and recommendation integrated system (DRIS) norms for the rubber tree clone FX3864 (Hevea brasiliensis) under the conditions of the Colombian Eastern Plains for the elements N, P, K, Ca, Mg, Na, S, Fe, Cu, Zn and B. For this purpose, 77 foliar samples were taken from a 10- to 12-year-old com-mercial crop. The element ratios that contributed the grea-test variance between high- and low- productivity populations were selected for conversion into norms. Of the 132 possible ratios, 66 were selected, with ratios including P/N, N/K and NXCa proving most important. The most limiting nutrients were K and N when deficient and Ca and S when in excess. Incluye referencias bibliográficas

El presente trabajo se plantea desde la perspectiva de la utilización de residuos de neumáticos que están fuera de uso. Se conoce el problema de sus depósitos en distintos países y la gran demanda de éstos como residuos, la falta de legislación de los vertederos, y la proliferación de enfermedades e insectos que se generan en ellos. Por estos motivos, y aprovechando las nuevas tecnologías en maquinaria de fabricación de ligantes asfálticos, es que se vio la necesidad de estudiar la incorporación del polvo de neumáticos en ligantes asfálticos. Desde el LEMaC, Centro de Investigaciones Viales, se impulsó la propuesta de utilizar el polvo de neumáticos que la empresa Molicaucho produce. A su vez, se planteó realizar la dispersión del caucho en la refinería con que cuenta la empresa REPSOL – YPF en la ciudad de Ensenada, para que luego de verificar su eficacia, realizar una mezcla asfáltica densa para la utilización como capa de rodamiento. Es así como, se estudiaron las principales características del asfalto base, el caucho, la dispersión de ambos, los áridos para formular la mezcla densa, la elaboración en planta industrial del asfalto – caucho, su colocación en obra con un tramo experimental en la ciudad de La Plata y la posterior verificación de la mezcla por medio de extracción de testigos.

L'òxid de zinc és un compost àmpliament utilitzat en la indústria del cautxú a causa de les excel•lents propietats que mostra com activador per a la vulcanització amb sofre. Malgrat les seves característiques superiors, hi ha una creixent preocupació sobre els seus efectes mediambientals i nombrosos estudis s’han portat a terme per tal de reduir els nivells de ZnO als compostos de cautxú o per a substituir-lo. Entre totes les alternatives propostes per reduir la quantitat d'òxid de zinc, l'ús de nanopartícules de ZnO amb una alta superfície específica sembla prometedor. Una altra proposta per reduir els nivells de ZnO que ha estat estudiada per nombrosos autors és l'ús d'altres òxids metàl•lics, com el CaO, MgO, CdO, CuO, PbO i NiO. En aquest treball, nous activadors amb un reduït contingut de zinc han estat desenvolupats per tal de reduir l'impacte ambiental de la indústria del cautxú. Nanopartícules d'òxids metàl•lics mixtes de zinc i altres metalls s’han sintetitzat per tal de beneficiar-se de la seva grandària i aprofitar-se del comportament tant del ZnO com del MgO a la vulcanització amb sofre. Un altre gran problema mediambiental relacionat amb la indústria del cautxú és la gestió dels compostos de cautxú que han arribat al final de la seva vida útil, especialment de pneumàtics. L'impacte mediambiental dels pneumàtics, juntament amb els problemes econòmics relacionats amb la seva gestió i eliminació, ha donat lloc a una gran varietat d'estudis per desenvolupar tecnologies per a reutilitzar i reciclar els pneumàtics fora d'ús. L'ús de cautxú recuperat o regenerat en mescles amb cautxú verge s’ha investigat per diferents autors. No obstant això, la migració de les substàncies químiques entre el cautxú triturat i la matriu verge no ha estat considerada com un avantatge per tal d'utilitzar el cautxú de pneumàtics fora d'ús com un activador i, per tant, reduir els nivells de zinc emprats en els compostos de cautxú i introduir noves aplicacions per als pneumàtics fora d'ús. Aquest enfocament ha estat investigat en aquesta tesi., El óxido de zinc es un compuesto ampliamente utilizado en la industria del caucho debido a las excelentes propiedades que muestra como activador para la vulcanización con azufre. A pesar de sus características superiores, existe una creciente preocupación acerca de sus efectos medioambientales y numerosos estudios han sido realizados con el fin de reducir los niveles de ZnO en los compuestos de caucho o para sustituirlo. Entre todas las alternativas propuestas para reducir la cantidad de óxido de zinc, el empleo de nanopartículas de ZnO con una alta superficie específica parece ser prometedor. Otro propuesta para reducir los niveles de ZnO que ha sido estudiado por numerosos autores es el uso de otros óxidos metálicos, como el CaO, MgO, CdO, CuO, PbO y NiO. En este trabajo, nuevos activadores con un reducido contenido de zinc han sido desarrollados con el fin de reducir el impacto ambiental de la industria del caucho. Nanopartículas de óxidos metálicos mixtos de zinc y otros metales han sido sintetizados con el fin de beneficiarse de su tamaño y aprovecharse del comportamiento tanto del ZnO como del MgO en la vulcanización con azufre. Otro gran problema medioambiental relacionado con la industria del caucho es la gestión de los compuestos de caucho que han alcanzado el final de su vida útil, especialmente de neumáticos. El impacto medioambiental de los neumáticos, junto con los problemas económicos relacionados con su gestión y eliminación, ha dado lugar a una gran variedad de estudios para desarrollar tecnologías para reutilizar y reciclar los neumáticos fuera de uso. El uso de caucho recuperado o regenerado en mezclas con caucho virgen ha sido investigado por diferentes autores. Sin embargo, la migración de las sustancias químicas entre el caucho triturado y la matriz virgen no ha sido considerada como una ventaja con el fin de utilizar el caucho de neumáticos fuera de uso como un activador y, por lo tanto, reducir los niveles de zinc empleadas en los compuestos de caucho e introducir nuevas aplicaciones para los neumáticos fuera de uso. Este enfoque ha sido investigado en esta tesis., Zinc oxide is a widely used compound in rubber industry due to the excellent properties that shows as activator for sulphur vulcanisation. Despite its superior characteristics, there is an increased concern about its environmental effects and several research studies have been carried out in order to reduce the ZnO levels in rubber compounds or substitute it. Between all the alternatives proposed to reduce the ZnO levels, the use of nano-sized ZnO particles with high surface area seems to be promising. Another approach to reduce the ZnO levels that has been studied by many authors is the use of alternative metal oxides, such us CaO, MgO, CdO, CuO, PbO and NiO. In this work, novel activators with reduced zinc content have been developed in order to reduce the environmental impact of the rubber industry. Mixed metal oxides nanoparticles of zinc and other metal have been synthesised with the aim of profiting from its size and to take advantage of the behaviour of both ZnO and MgO in sulphur vulcanisation. Another environmental problem related to the rubber industry is the management of end of life and waste rubber, especially tyres. The environmental impact of waste tyres, together with the economic problems related with the management and disposal, has led to a great variety of studies to develop technologies to re-use and recycle waste tyres. The use of reclaimed or regenerated rubber in blends with virgin rubber has been investigated by different authors. However, the migration of chemicals between the crumb and the matrix has not been considered as an advantage in order to use tyre crumb as an activator and, therefore, reduce the zinc levels employed in rubber compounds and introducing new applications for the waste rubber from end of life tyres. This approach has been investigated in this thesis.

Made available in DSpace on 2013-08-12T19:08:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-01 Made available in DSpace on 2013-09-30T19:20:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:33:08Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T15:33:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-01 Plantacoes Michelin Ltda. The tingid Leptopharsa heveae, known as the lace bug, occurs in large populations in rubber tree plantations, limiting the production of latex due to losses of photosynthetic area and weakening of the infested trees. The alternative for the use of insecticides would be the release of biological control agents, but little is known about the natural enemies of L. heveae. The parasitoid Erythmelus tingitiphagus parasitizes eggs of the lace bug in rubber tree plantations. The knowledge of the population dynamics and the peak of occurrence of economically important insect species and their natural enemies are indispensable requirements for the establishment of efficient and rational control strategies. The objective of this work was to study the population dynamics of L. heveae and E. tingitiphagus in rubber tree plantations in the county of Itiquira, MT, Brazil. Mature folioles were collected weekly from the lower stratum of the canopy of the tree clones RRIM 600, PR 255, GT 1, PB 235 and PB 217, from August/2005 to February/2006. The parasitoid was observed during the whole study period. The population peaks of the populations of the L. heveae and E. tingitiphagus in the study area occurred at the end of October and beginning of November. This result demonstrates that measures for the control of L. heveae and population increase of E. tingitiphagus must be adopted before the peak population of this pest in cultivated rubber plantations. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Acre Ctr Pesquisa Agroflorestal Acre CPAF, Rio Branco, AC, Brazil IB APTA, BR-13012970 Campinas, SP, Brazil Univ Estado Mato Grosso UNEMAT, BR-78690000 Nova Xavantina, MT, Brazil Univ Estadual Paulista Fac Ciencias Agr & Vet UNE, BR-14884900 Jaboticabal, SP, Brazil Univ Estadual Paulista Fac Ciencias Agr & Vet UNE, BR-14884900 Jaboticabal, SP, Brazil

The purpose of this study was to elaborate a preliminary list of the mite species associated with rubber trees in the municipality of Santana, in the state of Amapá, Brazil. Two collections of rubber tree leaves were conducted on May 2nd and June 5th , 2010. Twenty-five plants were sampled at random. Three leaves were collected per plant, from the lower third of the crown. The samples were placed in paper bags, packed in an isothermal box chilled gel-based pulp plant (Gelo-X®), and transported to the Entomology Laboratory at Embrapa Amapá, in Macapá. The leaflets were examined under a stereomicroscope, and the mites found on the adaxial and abaxial surfaces of the leaves were collected with a stilet, mounted on microscope slides in Hoyer's medium, and later identified. We collected a total of 1,722 mites of 10 families: Acaridae, Cunaxidae, Eriophyidae, Iolinidae, Phytoseiidae, Stigmaeidae, Tarsonemidae, Tenuipalpidae, Tydeidae, and Winterschmidtiidae, in addition to unidentified species of the suborders Oribatida and Astigmatina. The family Phytoseiidae represented only 2.90% of specimens collected, but showed the highest species richness (5 species). The only representative of Tenuipalpidae was Tenuipalpus heveae Baker, 1945, but 81.13% of the mites collected in this study belonged to this species. O objetivo deste estudo foi elaborar uma lista preliminar das espécies de ácaros associadas à seringueira, no município de Santana, Estado do Amapá. Foram realizadas duas coletas de folhas de seringueira, nos dias 2 de maio e 5 de junho de 2010. Foram tomadas aleatoriamente 25 plantas, de cada uma das quais foram coletadas três folhas, no terço inferior da copa. As amostras foram acondicionadas em sacos de papel, mantidas em caixa isotérmica refrigerada com gel à base de celulose vegetal (Gelo-X®) e transportadas até o Laboratório de Entomologia da Embrapa Amapá, em Macapá. A triagem dos folíolos foi realizada com o auxílio de estereomicroscópio. Os ácaros encontrados nas faces adaxial e abaxial das folhas foram capturados com um estilete, montados em lâminas de microscopia em meio de Hoyer e, posteriormente, identificados. Foram coletados 1.722 ácaros, pertencentes a dez famílias: Acaridae, Cunaxidae, Eriophyidae, Iolinidae, Phytoseiidae, Stigmaeidae, Tarsonemidae, Tenuipalpidae, Tydeidae e Winterschmidtiidae, além de espécies não identificadas das subordens Oribatida e Astigmatina. A família Phytoseiidae representou apenas 2,90% do total de espécimes coletados, porém apresentou a maior riqueza em espécies (cinco espécies). A família Tenuipalpidae, embora representada apenas por Tenuipalpus heveae Baker, 1945, apresentou o maior número de espécimes capturados (81,13%).

Solar radiation is an important factor for plant growth, being its availability to understory crops strongly modified by trees in an Agroforestry System (AFS). Coffee trees (Coffea arabica cv. Obatã IAC 1669- 20) were planted at a 3.4 x 0.9 m spacing inside and aside rows of monocrops of 12 year-old rubber trees (Hevea spp.), in Piracicaba-SP, Brazil (22°42'30"S, 47°38'00"W - altitude: 546m). One-year-old coffee plants exposed to 25; 30; 35; 40; 45; 80; 90; 95 and 100% of the total solar radiation were evaluated according to its biophysical parameters of solar radiation interception and capture. The Goudriaan (1977) adapted by Bernardes et al. (1998) model for radiation attenuation fit well to the measured data. Coffee plants tolerate a decrease in solar radiation availability to 50% without undergoing a reduction on growth and LAI, which was approximately 2m2.m-2 under this condition. Further reductions on the availability of solar radiation caused a reduction in LAI (1.5m2.m-2), thus poor land cover and solar radiation interception, resulting in growth reduction.