Upcycling of polyester fiber and garment-textile waste

This research is part of the project MATE.RIA, aimed at extending the life of post-consumer garment-textiles and identifying a new market for polyethylene terephthalate (PET) waste produced during fiber manufacturing. Here we investigate the possibility of developing innovative products exploiting the thermal insulation capability of textiles for architectural applications. The materials considered in this work are the polyester fiber waste from the production line and the end-of-life garment-textiles, provided by the project partners FranaPolifibre and HUMANA, respectively. Gel Permeation Chromatography, Differential Scanning Calorimetry, and uniaxial tensile tests were used to preliminarily determine structural, thermal, and mechanical properties. The materials were then used to produce prototype of thermoregulatory panels, which were obtained by applying a layer of PET to one or both fabric surfaces: the fabric acts as a thermal insulator while the PET layer provides rigidity. Two techniques were used to apply PET layers on a fabric: textile dip coating in PET solution and coupling with cast film. Both processes required the preparation of a PET solution. Hexafluoro isopropanol (HFIP) has been selected as solvent due to its compatibility with the textiles. A solution of 250 g/L was utilized for dip coating. Textiles varying in percentages of cotton and polyester were dip-coated in a solution on their “Right side”, “Wrong side”, or on both surfaces. Cast films were obtained by 200 g/L of PET/HFIP. Dried membranes that ranged in thickness from 157 to 190 μm were coupled with the fabrics after wetting the membrane surface with additional HFIP. The thermal regulation capability of the panel could be modified through Phase Change Materials (PCMs) inclusion. Composites' morphological and porosity characteristics have been examined via optical microscopy analysis. Incorporating PCMs suitable for architectural applications into the composite is under investigation

Determinación de agua

El agua merece especial atención porque usualmente se debe indicar el contenido de humedad de una muestra analítica. En las muestras líquidas, el agua puede considerarse como diluyente o como impureza. Las sales de ácidos inorgánicos y orgánicos así como otros compuestos cristalinos pueden retener agua de diferentes formas: - Agua enlazada - Agua adherida o libre El agua libre (no enlazada) es humedad adsorbida en la superficie del sólido, y el agua enlazada es agua de cristalización (agua de hidratación). Por consiguiente, se tiene al agua libre como una impureza, mientras que el agua enlazada, aunque en realidad es un diluyente, de hecho forma parte de la estructura del cristal.Facultad de Ciencias Exacta

Modelling mixed-mode fracture in poly(methylmethacrylate) using peridynamics

AbstractPeridynamics (Silling (2000)) is a non-local continuum theory that is particularly suited to handle discontinuities in the displacement field, such as those arising during fracture. Peridynamics prescribes that each material point interacts with all its neighbors contained in a sphere of given radius; this assumption introduces a characteristic length scale in the continuum description. In a nutshell, the interactions between material points depend on their relative distance; in the peridynamics framework this distance is called the “bond length”. The equations of motion, holding at each material point, link the material point acceleration to the integral over the point neighborhood of a force density field, whose strength depend on bond-stretches, i.e. the ratio of the actual bond-length over the initial one. In these equations the displacement gradient does not appear, thus naturally allowing for discontinuities in the displacement field to occur. As to failure, the simplest possible damage description is provided by an interaction law prescribing the force to vanish when a critical bond-stretch threshold is crossed; this parameter can be related to the Mode I critical strain energy release rate. A single parameter is needed to describe failure, in principle under every possible loading condition.In this work the predictive abilities of peridynamics were checked against experimental results in the case of mixed-mode failure of brittle polymers. Pre-cracked poly(methylmethacrylate) (PMMA) samples were tested using different specimens, in order to obtain Mode I, Mixed-Mode and Mode II loading conditions. The material was assumed to behave according to a peridynamics brittle elastic material model; the parameters needed to calibrate the elastic behavior were determined from Mode I tests, as was the critical stretch.The peridynamics simulations of mixed-mode tests were able to catch the correct fracture initiation load and to provide a fair description of the crack path under different conditions. The peridynamics model was also able to qualitatively capture the typical “nail” shape assumed by the crack front during propagation

The effects of fibers on the performance of bituminous mastics for road pavements

The experimental investigation herein described is aimed at understanding the effects of cellulose-based fibers on the mechanical properties of bituminous mastics for paving applications. Three bitumen (two of which modified with SBS polymers), a calcareous filler and four different types of fiber with varying content were used to prepare the investigated mastics. The filler to bitumen ratio was maintained constant. The laboratory investigations were focused on empirical tests (Needle Penetration and Ring and Ball – R&B – Temperature) and dynamic-mechanical tests, the latter performed in a wide range of temperatures. Results suggest that fibers improve the behavior of mastics for hot mix asphalts, particularly with respect to the prevention of rutting phenomena at high service temperatures

New distribution records for the American Coot (Fulica ardesiaca), the Puna Teal (Anas puna), the Andean Ruddy Duck (Oxyura ferruginea), and the Puna Ibis (Plegadis ridgwayi), in the Angostura Dam, Tafí del Valle, Tucumán, Argentina

Distribution records for four species of birds are reported from studies carried out between 2004 and 2005 at La Angostura Dam (26º55'S, 65º41'W). The species are known to inhabit lakes, lagoons, pools, marshes and streams, generally above 3000 m. Here they are found at a lower elevation, circa 2000 m. They are Fulica ardesiaca (American Coot), present all year, with high abundance and continuous nest building records; Anas puna (Puna Teal), observed in the area during winter; Oxyura ferruginea (Andean Ruddy Duck), present throughout the year, with greater abundance in winter, and Plegadis ridgwayi (Puna Ibis), with a few individuals observed in summer, autumn and winter.Distribution records for four species of birds are reported from studies carried out between 2004 and 2005 at La Angostura Dam (26o55'S, 65o41'W). The species are known to inhabit lakes, lagoons, pools, marshes and streams, generally above 3000 m. Here they are found at a lower elevation, circa 2000 m. They are Fulica ardesiaca (American Coot), present all year, with high abundance and continuous nest building records; Anas puna (Puna Teal), observed in the area during winter; Oxyura ferruginea (Andean Ruddy Duck), present throughout the year, with greater abundance in winter, and Plegadis ridgwayi (Puna Ibis), with a few individuals obser ved in summer, autumn and winter.Fil: Echevarria, Ada Lilian. Fundación Miguel Lillo; ArgentinaFil: Chani, Jose Maria. Universidad Nacional de Chilecito; ArgentinaFil: Marano, Claudia Fabiana. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Cocimano, Maria Constanza. Fundación Miguel Lillo. Dirección de Zoología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin

Composition of a bird community at La Angostura Reser voir, Tafí del Valle, Tucumán, Argentina

Los estudios de las comunidades de aves contribuyen al conocimiento del rol que los humedales pueden cumplir en la conservación de la biodiversidad dentro de los biomas en los que están ubicados. Se realizaron censos de transecta de faja y se calcularon abundancia relativa, frecuencia e índice de importancia relativa. En los 121 censos realizados, se registraron 43.243 individuos, pertenecientes a 68 especies, más 10 especies observadas fuera de censo, distribuidas en 27 familias y 12 ordenes. Las especies con mayores valores en los índices calculados fueron Anas georgica, Fulica ardesiaca, Fulica armillata, Anas flavirostris, Phalacrocorax brasilianus y Vanellus chilensis. Se registraron cuatro nuevas especies de distribución altoandinas (Fulica ardesiaca, Oxyura ferruginea, Anas puna y Plegadis ridgwayi) y la nidificación de cuatro Fulica spp. en forma simultánea. Además se señala por primera vez la nidificación de Coscoroba coscoroba para esta altitud.Studies on bird communities help understand the role wetlands may play in the conservation of biodiversity of the biomes they’re located in. One-hundred-and-twenty-one transect census were performed. Relative abundance, frequency and index of relative impor tance were calculated. We recorded 43,243 specimens, belonging to 68 species, from 27 families and 12 orders. The species with the greatest index values were Anas georgica, Fulica ardesiaca, Fulica armillata, Anas flavirostris, Phalacrocorax brasilianus y Vanellus chilensis. Four new species from the high Andes wetlands were recorded (Fulica ardesiaca, Oxyura ferruginea, Anas puna y Plegadis ridgwayi), and the simultaneous nidificación of four Fulica spp. was observed. Nidification for Coscoroba coscoroba is reported for the first time at this altitude.Fil: Echevarria, Ada Lilian. Fundación Miguel Lillo; ArgentinaFil: Marano, Claudia Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Chani, Jose Maria. Universidad Nacional de Chilecito; ArgentinaFil: Cocimano, Maria Constanza. Fundación Miguel Lillo. Dirección de Zoología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin

Effect of processing on the environmental stress cracking resistance of high-impact polystyrene

Processing conditions have a strong effect on the final mechanical properties of products made of polymeric materials. Relevant phenomena most commonly include thermal stresses, physical ageing, frozen-in strains and molecular orientation. In this work, two different high-impact polystyrenes, processed by thermoforming, were considered: a “standard” one and a grade specifically resistant to Environmental Stress Cracking (ESC). The main effect induced by thermoforming was molecular orientation. The local degree of orientation was measured on a thermoformed product and its effect on the material ESC behavior in sunflower oil was studied. A Fracture Mechanics approach was applied to evaluate the fracture resistance of the two materials. Results show that a higher degree of orientation increases the fracture resistance in air but has no effect on the (expectedly lower) resistance in the active oil environment

New phylogenetic insights into Saprolegniales (Oomycota, Straminipila) based upon studies of specimens isolated from Brazil and Argentina

Saprolegniales is a complex and monophyletic order of oomycetes. Their members inhabit terrestrial, freshwater, and marine ecosystems and have a worldwide distribution. In these ecosystems, they are found as saprobes, parasites, or even pathogens of animals and plants of economic importance. In this study, a concatenate phylogeny of the partial LSU and complete ITS rDNA regions is presented, including isolates from Brazil and Argentina, which were sequenced after a detailed morphological analysis. Among the sequenced species, Achlya orion, Leptolegnia eccentrica, Phragmosporangium uniseriatum, and Pythiopsis irregularis are included for the first time in a phylogeny. Our results are in agreement with the recent informal proposals outlined in taxonomic overviews of the Oomycota of G.W. Beakes and collaborators, who placed the family Verrucalvaceae into the Saprolegniales and introduced the family Achlyaceae to group Achlya s.s., Brevilegnia, Dictyuchus, and Thraustotheca. These results also support the transference of Achlya androgyna to Newbya. Leptolegnia appears as paraphyletic, with the separation of L. eccentrica from the other species of this genus. In addition, Phragmosporangium, which is herein sequenced for the first time, clustered as sister to some species of Aphanomyces, including the type species, A. stellatus.Fil: Rocha, Sarah C. O.. Instituto de Botânica. Núcleo de Pesquisa em Micologia; BrasilFil: Lopez Lastra, Claudia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Marano, Agostina Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Instituto de Botânica. Núcleo de Pesquisa em Micologia; BrasilFil: de Souza, José Ivanildo. Instituto de Botânica. Núcleo de Pesquisa em Micologia; BrasilFil: Rueda Páramo, Manuel Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Pires Zottarelli, Carmen L. A.. Instituto de Botânica. Núcleo de Pesquisa em Micologia; Brasi