4,285 research outputs found
Educação ambiental e mídia: análise das concepções de estudantes de comunicação a partir de suas produções jornalísticas
A investigação reportada no presente trabalho teve como objetivo analisar a inserção das questões ambientais em reportagens produzidas por alunos de um curso de Comunicação Social com habilitação em Jornalismo, buscando compreender as concepções de Educação Ambiental presentes na argumentação utilizada e a influência de tais concepções na definição dos temas abordados. Os resultados demonstraram uma preponderância de representações identificadas como utilitárias e sem abordagens críticas, em consonância com o discurso presente nos grandes veículos de comunicação. Diante disso, os resultados reforçam a necessidade de se trabalhar o comprometimento de profissionais de comunicação com seu papel educativo no contexto atual
Impact of cherry, acacia and oak chips on red wine phenolic parameters and sensory profile
Aim: The evolution of global phenolic parameters and the sensory profile of a Portuguese red wine aged for 90 days in contact
with wood chips from different species were evaluated.
Methods and results: For this purpose, wood chips from cherry (Prunus avium), acacia (Robinia pseudoacacia) and two oak
species (Quercus petraea and Quercus pyrenaica) were added to a Portuguese red wine. Various global phenolic parameters of
red wines were studied during the aging process (90 storage days). In addition, a sensory analysis was made after the 90-day
aging period to determine the impact of the use of different wood chip species on red wine sensory profile. The results showed
that during the aging period, only a few differences were detected between the wines. However, after 90 aging days, in general
the wines aged in contact with cherry wood tended to have the lowest values for several phenolic parameters. For sensory
parameters, the wine aged in contact with French oak chips showed significantly higher scores for several aroma descriptors,
while for visual and taste descriptors no statistical significant differences were found between the wines.
Conclusion: At the concentration used (3 g wood chips/L wine), the different wood chip species studied had no clear influence
on the evolution of the majority of the red wine phenolic parameters. However, from a sensory point of view, the use of
different wood species induced greater differentiation, especially for aroma descriptors.
Significance and impact of the study: The outcomes of this study would be of practical interest to winemakers and regulatory
institutions since they could improve the knowledge of the impact of alternative wood chip species, namely acacia and cherry,
on red wine qualityinfo:eu-repo/semantics/publishedVersio
Gestão do patrimônio e identidade: centro de referência cultural e ecológica do engenho São João
O Engenho São João está localizado na Ilha de Itamaracá, no litoral do Estado de Pernambuco, Brasil. As primeiras fontes que fazem referência ao Engenho datam de 1747 e desde então ele é palco de importantes acontecimentos, como, por exemplo, o nascimento do Conselheiro João Alfredo em 1835, importante político abolicionista do período imperial brasileiro e a implantação da moenda a vapor, fazendo do local marco da modernização da indústria açucareira, precursor das usinas de açúcar no Brasil.
Em 1938, as terras do Engenho São João e todas as suas benfeitorias, mecanismos, matas e logradouros, são adquiridas pelo Estado, sendo aí instalada a Colônia Agrícola de Itamaracá, uma penitenciária em regime semi-aberto que funciona até os dias atuais (havendo atualmente uma decisão governamental de retirá-la até o ano de 2010). Em 1983, o engenho que contava com 2 edifícios referentes à época do engenho e 8 à época do funcionamento da Penitenciária, foi tombado pelo Estado. Em 1998, a Mata de São João, repleta de trilhas pitorescas, é reconhecida pela Unesco como Reserva da Biosfera da Mata Atlântica. Em 2007, após algumas intervenções de estabilização e recuperação das antigas edificações, o local passa a ser alvo de um projeto integrado, prevendo a preservação de sua paisagem cultural, através da implantação, em uma área de 20,83 ha, do Centro de Referência Cultural e Ecológica do Engenho São João. Nele deverão estar abrigados e preservados o ambiente natural, hábitos, fazeres, manualidades características locais e seus cenários de apresentação: presente e passado da Ilha e seus personagens consagrados. O presente artigo tem por objetivo empreender um debate em torno da interpretação, conservação e preservação dos edifícios do Engenho São João, tendo em vista a diversidade histórica e cultural que emana desse patrimônio, estabelecendo um fio condutor que evidencie a identidade do lugar.Tópico 1: Aspectos teóricos, históricos, legales, económicos y tecnológicos de la restauración y conservación de bienes patrimoniales
Tensile behaviour of a structural adhesive at high temperatures by the extended finite element method
Component joining is typically performed by welding, fastening, or adhesive-bonding. For bonded aerospace applications, adhesives must withstand high-temperatures (200°C or above, depending on the application), which implies their mechanical characterization under identical conditions. The extended finite element method (XFEM) is an enhancement of the finite element method (FEM) that can be used for the strength prediction of bonded structures. This work proposes and validates damage laws for a thin layer of an epoxy adhesive at room temperature (RT), 100, 150, and 200°C using the XFEM. The fracture toughness (G Ic ) and maximum load ( ); in pure tensile loading were defined by testing double-cantilever beam (DCB) and bulk tensile specimens, respectively, which permitted building the damage laws for each temperature. The bulk test results revealed that decreased gradually with the temperature. On the other hand, the value of G Ic of the adhesive, extracted from the DCB data, was shown to be relatively insensitive to temperature up to the glass transition temperature (T g ), while above T g (at 200°C) a great reduction took place. The output of the DCB numerical simulations for the various temperatures showed a good agreement with the experimental results, which validated the obtained data for strength prediction of bonded joints in tension. By the obtained results, the XFEM proved to be an alternative for the accurate strength prediction of bonded structures
A Study on Microstructure Characteristics of TEPs-modified Adhesives
Thermally expandable particles (TEPs) were developed by Dow Chemical Co in the early 1970´s [1] and
were further developed by others [2, 3]. They are particles made up of a thermoplastic shell filled with liquid
hydrocarbon. On heating them, two transformations will occur. One is the softening of shell material and the
other is the gasification of the hydrocarbon liquid inside it. As a consequence, the shell will expand as the gas
inside it will push the softened shell from inside out causing it to grow in size [4]. When fully expanded, the
growth in volume of the particle can be from 50 to 100 times [3]. Owing to this unique behaviour, TEPs are
used by the industry in a wide variety of applications mainly for weight reduction and appearance
improvement for thermoplastics, inks, and coatings. In adhesive bonding, TEPs have been used for recycling
purposes. Moreover, TEPs might be used to modify structural adhesives for other new purposes, such as: to
increase the joint strength by creating an adhesive functionally modified along the overlap of the joint by
gradual heating and/or to heal the adhesive in case of damage
Characterization of quaternary ammonium compounds in Flourensia xerophytic communities and response to UV-B radiation
As part of ongoing studies aimed at characterizing molecular components involved in the ecophysiological adaptations of native xerophytic plants from central Argentina, we demonstrated the presence of compatible solutes in Flourensia campestris (FC) and Flourensia oolepis (FO), specifically glycine betaine (GB) through TLC, LC, 1H NMR and 13C-NMR. GB content (leaves: 38±7μmolg-1 DW; adult plants>seedlings), and distribution (capitula>vegetative leaves>reproductive leaves>shoots>roots) were similar to other quaternary ammonium compound (QAC) accumulators. Flourensia seedlings from both species protected from UV-B exposure - a major abiotic stress in these natural environments - showed a significant increase of GB in the leaves (p<0.01) and a significant decrease in the roots (p<0.05). In FC and FO xerophytic shrub-dominated communities QACs were detected for the first time in 41% of co-occurring species (N=39), 14 of 28 natives (50%) and 2 of 11 exotics (18%), being GB in natives only (57% of QAC accumulators). GB may be considered as a chemotaxonomical character for the genus Flourensia, since it was also detected in Flourensia hirta, Flourensia niederleinii, Flourensia riparia, Flourensia fiebrigii, Flourensia macroligulata and Flourensia heterolepis. Our controlled UV-B experiments, set up in the same natural environment where these species grow, clearly show that solar UV-B - and therefore oxidative stress - is involved in regulating GB contents and within-plant distribution in FC and FO seedlings. The findings in Flourensia co-occurring native species suggest that QACs accumulation may be considered as a community-specific ecophysiological trait in these xerophytic environments. .Fil: Piazza, Leonardo A.. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: López, D.. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: Silva, Mariana Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: Lopez Rivilli, Marisa Juana. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cantero, Juan Jose. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Tourn, G. M.. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: Scopel, Ana Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentin
Strength improvement of adhesively-bonded joints using a reverse-bent geometry
Adhesive bonding of components has become more efficient in recent years due to the developments in adhesive technology, which has resulted in higher peel and shear strengths, and also in allowable ductility up to failure. As a result, fastening and riveting methods are being progressively replaced by adhesive bonding, allowing a big step towards stronger and lighter unions. However, single-lap bonded joints still generate substantial peel and shear stress concentrations at the overlap edges that can be harmful to the structure, especially when using brittle adhesives that do not allow plasticization in these regions. In this work, a numerical and experimental study is performed to evaluate the feasibility of bending the adherends at the ends of the overlap for the strength improvement of single-lap aluminium joints bonded with a brittle and a ductile adhesive. Different combinations of joint eccentricity were tested, including absence of eccentricity, allowing the optimization of the joint. A Finite Element stress and failure analysis in ABAQUS® was also carried out to provide a better understanding of the bent configuration. Results showed a major advantage of using the proposed modification for the brittle adhesive, but the joints with the ductile adhesive were not much affected by the bending technique
Modelling adhesive joints with cohesive zone models: effect of the cohesive law shape of the adhesive layer
Adhesively-bonded joints are extensively used in several fields of engineering. Cohesive Zone Models (CZM) have been used for the strength prediction of adhesive joints, as an add-in to Finite Element (FE) analyses that allows simulation of damage growth, by consideration of energetic principles. A useful feature of CZM is that different shapes can be developed for the cohesive laws, depending on the nature of the material or interface to be simulated, allowing an accurate strength prediction. This work studies the influence of the CZM shape (triangular, exponential or trapezoidal) used to model a thin adhesive layer in single-lap adhesive joints, for an estimation of its influence on the strength prediction under different material conditions. By performing this study, guidelines are provided on the possibility to use a CZM shape that may not be the most suited for a particular adhesive, but that may be more straightforward to use/implement and have less convergence problems (e.g. triangular shaped CZM), thus attaining the solution faster. The overall results showed that joints bonded with ductile adhesives are highly influenced by the CZM shape, and that the trapezoidal shape fits best the experimental data. Moreover, the smaller is the overlap length (LO), the greater is the influence of the CZM shape. On the other hand, the influence of the CZM shape can be neglected when using brittle adhesives, without compromising too much the accuracy of the strength predictions
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