Littérature scientifique sur le sujet « Cork agglomerates »
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Articles de revues sur le sujet "Cork agglomerates"
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Reis, Luís G., P. Carvalho, C. Alves et Manuel de Freitas. « Mechanical Behaviour of Sandwich Beams Manufactured with Glass or Jute Fiber in Facings and Cork Agglomerates as Core ». Materials Science Forum 636-637 (janvier 2010) : 245–52. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.245.
Texte intégralRésumé :
The environment is a prominent issue today. Designing environmentally sustainable products is an attempt to address this question. In many cases, natural materials are environmentally friendly for product design manufacturing. The goal of this work is to study the mechanical behaviour of NL10 and NL30 cork agglomerates. Compression, shear and bending tests in sandwich specimens made of glass or jute fiber in facings and cork agglomerates as core were carried out. The sandwich specimens were manufactured by Resin Transfer Moulding (RTM) process. Results show that NL30 has a higher compression strength and shear resistance than NL10 agglomerate due to its manufacturing process, which originates superior density, but the NL30 agglomerate superior density is undesirable. Sandwich test specimens that presented failure by rupture of the core in both types of tests, core shear tests and three point bending tests, showed that the failure is mainly adhesive occurring between the adhesively joined cork grains. Since grains are unaffected and remain intact, it is possible to improve these materials by using better agglutinants and new bonding techniques with the intent of getting cork agglomerates with higher shear and flexural strength.
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Le Barbenchon, Louise, Jérémie Girardot, Jean-Benoît Kopp et Philippe Viot. « Strain Rate Effect on the Compressive Behaviour of Reinforced Cork Agglomerates ». EPJ Web of Conferences 183 (2018) : 03018. http://dx.doi.org/10.1051/epjconf/201818303018.
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The demand for bio-sourced materials is currently increasing. Cork material because of its unique properties (fire resistant, energy absorbing, …) is then an excellent candidate for a large set of applications. In order to widen its possible uses, cork agglomerates with reinforcements at a 0.48 density were studied to compare their mechanical performances with classical cork agglomerates. This paper investigates the effect of these foreign reinforcements on the properties of agglomerated cork under a compressive loading. The material behavior has been determined as a function of the average strain rate and the direction of solicitation. The microstructure was first observed through optical and scanning electronic microscopy, spotting charges between each cork bead. The characterisation of cork at different strain rates was then carried out. An electromechanical testing machine was used to apply an uniaxial compression at quasi-static strain rates. Reinforced agglomerated cork was found to be anisotropic and strain-rate dependant. Its micro-structure reveals at complex composite material influencing strongly mechanical properties. Both Young's modulus and absorbed energy density at 0.6 strain increase with the cross-head speed displacement. From 12.7 MPa and 0.77 J.mm-3 when compressed at 0.05 mm·min-1 to 19.9 MPa and 1.44 J·mm-3 at 500mm·min-1 in the Off-plane direction.
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XIAOZHOU, SONG, LIU GUORUI, FENG XUECHUN et ZHANG LI. « PREPARATION AND PROPERTIES OF AGGLOMERATED CORK PANELS BOUND WITH CHITOSAN BINDER ». WOOD RESEARCH 67(4) 2022 67, no 4 (11 août 2022) : 648–60. http://dx.doi.org/10.37763/wr.1336-4561/67.4.648660.
Texte intégralRésumé :
In this paper, acidified chitosan was used as an adhesive to prepare aldehyde-free, environmentally-friendly agglomerated cork panels by hot-pressing. After preparation, thephysical, mechanical, and the finishing properties of the chitosan-glued agglomerated cork panels were investigated. The optimal mass ratio of acetic acid solution (1wt.%) to chitosan was determined to be 30:1. The resulting hot-pressed agglomerated cork panels, which featured adensity of 0.55 g.cm-3and a thickness of 4 mm, exhibited a tensile strength of 1.70 MPa and athermal conductivity of 0.11W.m-1·K-1. The agglomerated cork panels coated with theoil-based polyurethane and water-based, acrylic-modified polyurethane paints exhibited significantly lower lightness and higher glossiness. The total color differences (ΔE*) ofboth agglomerated cork panels increased before and after finishing. The oil-based polyurethane paint coating exhibited high adhesion of paint film, reaching a level-0 adhesion, while thewater-based, acrylic-modified polyurethane paint coating achieved a level-1 adhesion. Theabrasion resistance results showed that the substrates of cork agglomerates coated two types of paint did not expose after undergoing abrasion for 100 revolutions atthe turntable speed of 60 rpm.
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Silva, José M., Tessaleno C. Devezas, A. Silva, L. Gil, C. Nunes et N. Franco. « Exploring the Use of Cork Based Composites for Aerospace Applications ». Materials Science Forum 636-637 (janvier 2010) : 260–65. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.260.
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Aerospace components are characterized by having high strength to weight ratios in order to obtain lightweight structures. Recently, different types of sandwich components using composite materials have been developed with the purpose of combining the effect of reinforced face-sheets with low weight core materials, such as honeycombs and foams. However, these materials must combine damage tolerance characteristics with high resistance under both static and dynamic loads. Cork composites can be considered as an alternative material for sandwich components since cork is a natural material with some remarkable properties, such as high damage tolerance to impact loads, good thermal and acoustic insulation capacities and excellent damping characteristics for the suppression of vibrations. The experiments carried out in this investigation were oriented in order to optimize the specific strength of cork based composites for sandwich components. Static bending tests were performed in order to characterize the mechanical strength of different types of cork agglomerates which were obtained considering distinct production variables. The ability to withstand dynamic loads was also evaluated from a set of impact tests using carbon-cork sandwich specimens. The results from experimental tests showed that cork agglomerates performance depends on the cork granulate size, the type of reinforcing elements and the bonding procedure used for the cohesion with the matrix material.
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Castro, Osvaldo, José M. Silva, Tessaleno Devezas, Arlindo Silva et Luís Gil. « Cork agglomerates as an ideal core material in lightweight structures ». Materials & ; Design 31, no 1 (janvier 2010) : 425–32. http://dx.doi.org/10.1016/j.matdes.2009.05.039.
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Macías-García, A., M. A. Díaz-Díez, E. M. Cuerda-Correa, A. Díaz-Parralejo et V. Gómez-Serrano. « Use of cork agglomerates as acoustic absorbents ». Materials Technology 24, no 2 (juin 2009) : 114–18. http://dx.doi.org/10.1179/175355509x425766.
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Knapic, Sofia, Carlos Pina dos Santos, Helena Pereira et José S. Machado. « Performance of Expanded High-Density Cork Agglomerates ». Journal of Materials in Civil Engineering 29, no 2 (février 2017) : 04016198. http://dx.doi.org/10.1061/(asce)mt.1943-5533.0001718.
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Fernandes, Fábio, Ricardo Alves de Sousa, Mariusz Ptak et Gonçalo Migueis. « Helmet Design Based on the Optimization of Biocomposite Energy-Absorbing Liners under Multi-Impact Loading ». Applied Sciences 9, no 4 (20 février 2019) : 735. http://dx.doi.org/10.3390/app9040735.
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Cellular materials have been used in many applications such as insulation, packaging, and protective gear. Expanded polystyrene has been widely used as energy-absorbing liner in helmets due to its excellent cost-benefit relation. This synthetic material can absorb reasonable amounts of energy via permanent deformation. However, in real-world accidents, helmets may be subjected to multi-impact scenarios. Additionally, oil-derived plastic is presently a major source of societal concern regarding pollution and waste. As a sustainable alternative, cork is a natural cellular material with great crashworthiness properties and it has the remarkable capacity to recover after compression, due to its viscoelastic behavior, which is a desired characteristic in multi-impact applications. Therefore, the main goal is to analyze the applicability of agglomerated cork as padding material in safety helmets. First, a finite element model of a motorcycle helmet available on the market was developed to assess its safety performance and to establish a direct comparison between expanded polystyrene and cork agglomerates as liners. Secondly, a new helmet model with a generic geometry was developed to assess the applicability of agglomerated cork as liner for different types of helmets, based on the head injury risk predictions by the finite element head model, YEt Another Head Model (YEAHM), developed by the authors. Several versions of helmet liners were created by varying its thickness and removing sections of material. In other words, this generic helmet was optimized by carrying out a parametric study, and by comparing its performance under double impacts. The results from these tests indicate that agglomerated cork liners are an excellent alternative to the synthetic ones. Thus, agglomerated cork can be employed in protective gear, improving its overall performance and capacity to withstand multi-impacts.
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Ptak, Mariusz, Paweł Kaczyński, Johannes Wilhelm, José M. T. Margarido, Paula A. A. P. Marques, Susana C. Pinto, Ricardo J. Alves de Sousa et Fábio A. O. Fernandes. « Graphene-Enriched Agglomerated Cork Material and Its Behaviour under Quasi-Static and Dynamic Loading ». Materials 12, no 1 (4 janvier 2019) : 151. http://dx.doi.org/10.3390/ma12010151.
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The use of cork for a variety of applications has been gaining significance due to environmental concerns and political agendas. Consequently, its range of applications is growing rapidly. In this work, aiming to improve its mechanical response for crashworthiness applications, cork agglomerates were enriched by small quantities of graphene oxide or graphene nanoplates in order to observe a resulting improvement of the mechanical behaviour during quasi-static and dynamic compressive loading cases. To produce homogenous cork agglomerates including graphene, the material was previously dispersed into granulated cork using stirrers to achieve a good distribution. Then, the typical procedure of compression and curing was carried out. Magnified images attest a good dispersion of graphene into the cork matrix. Mechanical testing was performed for a variety of graphene concentrations (0.1, 0.5 and 1.0 weight %), becoming clear that the beneficial effect of including graphene (either oxide or nanoplates) is related to a later densification stage while keeping the same stress plateau levels.
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Pereira, H., et E. Ferreira. « Scanning electron microscopy observations of insulation cork agglomerates ». Materials Science and Engineering : A 111 (mai 1989) : 217–25. http://dx.doi.org/10.1016/0921-5093(89)90215-3.
Texte intégralThèses sur le sujet "Cork agglomerates"
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Quinquet, Lucie. « Valorisation de la subérine et des produits du liège issu du massif des Maures pour la conception de matériaux éco-performants ». Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ5076.
Texte intégralRésumé :
Le liège, écorce issue du chêne-liège, le Quercus suber L. présente de nombreuses propriétés intéressantes telles que la compressibilité, flottabilité, et des propriétés isolantes. Ce matériau, surtout connu pour son utilisation dans les bouchons de vin et panneaux d'isolation, présente une particularité importante : lors de sa synthèse, le liège piège le dioxyde de carbone de l'atmosphère, participant ainsi à la médiation des gaz à effet de serre. Il est donc important de maximiser l'utilisation du liège avant combustion. Dans cette optique, l'agglomération du liège a été développée.L'agglomération du liège à l'heure actuelle, pose un problème quant à l'utilisation de colles polyuréthanes. Les polyuréthanes sont pétro-sourcées et utilisent des composés toxiques, relargués tout au long de la vie du matériau. Dans un premier temps ce travail de thèse explore et élabore une alternative biosourcée et non toxique aux colles polyuréthanes dans l'optique de fabriquer des agglomérés de particules de liège. L'huile de lin époxydée est ainsi utilisée comme matrice thermodurcissable après réticulation avec des polyacides biosourcés. Une autre alternative est étudiée en époxydant une molécule terpénique à haut niveau d'insaturations. Ainsi, cette molécule est envisagée comme un monomère et son impact sur la viscosité des mélanges et sur les cinétiques de polymérisation est étudié. Les agglomérés créés sont ensuite étudiés, caractérisés et comparés à des échantillons commerciaux. Cette preuve de concept a été validée à échelle semi-industrielle (quelques centaines de bouchons). Des agglomérés biosourcés sous forme de mousse sont aussi étudiés.La mise en forme du liège produit des tonnes de poudre de liège (20 % de la production totale de liège). Cette poudre est seulement brulée pour énergie et n'est pas valorisée efficacement. Le liège est composé en grande majorité de subérine, un polyester à longue chaines aliphatiques. Une fois extraite, la subérine se présente sous forme de ω-hydroxyacides et α,ω-diacides carboxyliques. La subérine est reconnue pour ses vertus anti-mutagénique, anti-rides, anti-bactériennes, etc. Ainsi, il est intéressant de la valoriser notamment comme additif. C'est pourquoi, dans un second temps, ce travail de thèse explore l'extraction la subérine, obtenant notamment une subérine très cristalline, sous forme de poudre qui se distingue d'une subérine plus résineuse contenant certains résidus du liège. Ces subérines sont ensuite intégrées dans des matrices thermoplastiques biosourcées pendant l'étape de polycondensation. La subérine classique est intégrée dans de l'acide poly(lactique) et la subérine poudre est intégrée dans du poly(hexamethylenefuranoate) et du poly(dodecylenefuranoate) dont les propriétés sont ensuite étudiéesCork, the bark of the cork tree named Quercus suber L., displays an array of interesting properties such as its compressibility, buoyancy and isolating properties thanks to its cellular structure. This material, most known for its application as cork stoppers and as isolating panels, has a particularity: during its synthesis, the cork bark traps carbon dioxide from the atmosphere, thereby participating in the greenhouse gases mitigation. Hence, the importance of using cork as long as possible before combustion. With this in mind, cork agglomerates were developed.The agglomerating process as it is today, poses threats regarding the use of polyurethane glues. Polyurethanes are petrobased and use components that are toxic and released throughout the material's life. In a first part, this work explores and develops a biobased nontoxic alternative to polyurethanes with the aim to create agglomerates. Thus, the use of epoxidized linseed oil as a thermoset matrix reticulated with biobased polyacids is explored. A second alternative is studied through the epoxidation of a small terpenoid molecule of high unsaturation degree. Hence, this epoxidized terpenoid compound is considered as an epoxy monomer impacting the viscosity of the mixtures and the polymerization kinetics is therefore studied. The ensuing agglomerates are then studied, characterized, and compared with commercial samples. This concept was validated at semi-industrial scale (hundreds of cork stoppers). Biobased agglomerates in the form of foams are also studied.The processing of cork creates tons of cork powder yearly (20 % of the total cork production). This powder is not being valorized to its full potential as it is only burnt for energy production. Cork is primarily made up of suberin, a polyester with great potential. Once extracted from cork, suberin is in the form of ω-hydroxyacids and α,ω-diacids. Suberin is known for its virtues as an antimutagen, anti-wrinkle, anti-bacterial and more. Hence, it is interesting to valorize it, as an additive for example. Accordingly, this work explores in a second part the extraction of suberin, obtaining notably an extract in a powder form that is crystalline. The obtained suberins (classic, paste and powder) are characterized and the classic and powder suberins are integrated in biobased thermoplastics during their polycondensation stage. Classic suberin is integrated in poly(lactic acid) and powder suberin is integrated in poly(hexamethylenefuranoate) and poly(dodecylenefuranoate). The properties of the ensuing formulated polymers are then studied
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Poeiras, Ana Patrícia Cebola. « Desenvolvimento de protótipos para pavimento e revestimento de parede em interiores com base em cortiça ». Master's thesis, ISA/UL, 2015. http://hdl.handle.net/10400.5/9245.
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Mestrado em Engenharia Florestal e dos Recursos Naturais - Ramo Engenharia dos Produtos Florestais - Instituto Superior de AgronomiaThe objective of this work is to find products for wall covering and flooring that can contribute to a greater valorization of the raw materials used - wood of Eucalyptus maculata, Eucalyptus botryoides and Quercus faginea, and black expanded cork agglomerate and regranulate – by developing greener and more value-added products for indoor use. Prototypes for flooring and wall covering were assembled. The prototypes for flooring had three layers: the previously mentioned woods and black cork agglomerate (top layer), pine wood (middle layer) and Rubbercork (bottom layer). The prototypes for wall coverings were based on the expanded cork regranulate and glue, adding barks or shavings of E. maculata, E. botryoides or Q. faginea. Physical and mechanical tests were made to measure hardness and swelling for the floor prototypes, concluding that the prototype with E. maculata has a higher hardness (41 N.mm-2) and lower swelling, and therefore an improved performance. For wall covering products physical and mechanical testes were made to determine hardness, strength and thermal conductivity. The prototypes made with bark chips had the highest density 316 kg.m-3), hardness (2,9 MPa), traction (0,19 MPa) and the highest thermal conductivity (0,044 W/m.K), and showed higher mechanical strength, in comparison to prototypes made with wood chips
Projecto WoodTech (Interreg, SUDOE)
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Santos, Paulo Miguel Trindade. « Estratégias para melhoramento das propriedades mecânicas de compósitos baseados em cortiça aglomerada ». Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/22346.
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Mestrado em Engenharia MecânicaThe use of cork material has been quickly spreading over the last years due to more care taken to environmental issues. The scrap coming from the production of traditional wine stopper or from the production of other cork products is generally triturated and agglomerated. The so-called agglomerated cork material has been finding a wide range of applications, being a good thermal and acoustic insulator, vibration and impact absorber. Nevertheless, scientific literature has been addressing agglomerated cork in a very general way and defining density and grain size as the two main defining parameters. Many studies that used agglomerated cork, failed to specify the parameters that were used in its production. This dissertation aims to show that, apart from density and grain size, there are other parameters, such as binder type or its quantity, may also have a very significant effect on the mechanical properties of cork in agglomerated form. To this end, the whole production process is detailed and a campaign of static and dynamic tests is carried out. Another goal of this dissertation was to determine the influence of the incorporation of nanomaterials, namely graphene and graphene oxide, as reinforcement on the agglomerated cork. With that goal, a second experimental campaign was planned and carried out. Consisting of quasi-static compression tests and burn tests. With the results obtain it was possible to conclude, that by altering the production parameters of the agglomerated cork it is possible to change its properties, to meet the requirements of the intended application.
Devido a uma maior preocupação ambiental, produtos à base de cortiça têm ganho relevo nas mais diversas áreas. As sobras da produção de rolhas e outros produtos de cortiça são geralmente triturados e aglomerados. O produto resultante é denominado cortiça aglomerada, sendo este um material com grande variedade de aplicações. A cortiça aglomerada é um bom isolante térmico e acústico, tendo ainda boa capacidade de absorver vibrações e energia de impactos. Todavia, a literatura científica tem apresentado a cortiça aglomerada de modo muito genérico e pouco especifico, definindo a densidade e o tamanho do grão utilizado na produção do aglomerado, como os dois principais parâmetros que influenciam as propriedades da cortiça aglomerada. Muitos estudos efetuados, que recorreram a cortiça aglomerada, são vagos nas informações que fornecem sobre o aglomerado de cortiça utilizado, ou mesmo em alguns casos estas informações encontram-se omissas. É o objetivo desta dissertação, demonstrar que existem outros parâmetros que influenciam as propriedades mecânicas da cortiça aglomerada e quantificar a sua influência. Para o efeito, uma campanha experimental com base em testes de compressão quase-estáticos e testes dinâmicos foi planeada e executada. Ainda como objetivo desta dissertação, foi estudar a influência da incorporação de nano materiais, nomeadamente grafeno e óxido de grafeno, como reforço na cortiça aglomerada. Com esse objetivo, uma segunda campanha experimental foi planeada e executada. Com o estudo dos dados obtidos foi possível provar que alterando os parâmetros de produção da cortiça aglomerada, é possível adequar as suas propriedades à aplicação a que destina.
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Tigre, Mafalda Silva. « Entry into the packaging market : The case of a portuguese cork-based company ». Master's thesis, 2021. http://hdl.handle.net/10400.26/38777.
Texte intégralRésumé :
The Company where the internship was carried out is a Portuguese cork-based B2B and B2C business, owning a worldwide stable and strong presence. It transforms cork composites, blended with other materials into new shapes, giving it new functionalities, and constantly searches for new challenges and develops new cork solutions.
This thesis aims to give a foundation for the Company to enter in the packaging market. Therefore, to understand the industry and analyze the Company’s potential to enter the market, this research adopted a case study approach, having desktop research, unstructured interviews, and meetings in a corporate setting as the data collection techniques.
The Company revealed to be in a good path to enter in the packaging market, specifically in the food & beverages and beauty & personal care markets. The cork-based materials with most potential for these markets are Cork Polymer Compounds, White Agglomerates and White Agglomerates with EVA. To enrich its future market competitiveness, the Company should invest in new product development, creating unique and innovative packaging materials and applications.
This thesis limitations resulted predominantly from the literature availability, and future research is proposed to address it.
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Peixoto, Demis Rodrigues. « Sandwich structures with cork agglomerate cores for thermal insulation purposes in aircraft ». Master's thesis, 2014. http://hdl.handle.net/10400.6/5222.
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As the use of sandwich structures continues to increase rapidly for applications ranging from satellites, aircraft, ships, automobiles, rail cars, wind energy systems, and bridge construction (to mention only a few), lightweight and high strength structures have become indispensable to many high-tech industries such as aerospace, civil infrastructure and vehicle. Therefore, the demand for new materials has been rising which in turn led to the increasing use of composite sandwich structures applications. Utilizing natural materials over traditional synthetic structures allows avoiding the use of oil and other carbon products for the fabrication, which were otherwise needed, thus resulting in a reduction of carbon emissions. Besides being renewable, these materials provide such benefits as being both biodegradable and recyclable.
In its simplest form a structural sandwich is composed of two thin stiff face sheets and a thick lightweight core bonded between them. The properties of primary interest for the core materials can be summarized as: low density, high shear modulus, high shear strength, elevated stiffness perpendicular to the faces and both good thermal and acoustic insulation characteristics. The commonly used core materials are foams, balsa wood and honeycombs, the latter consisting in superlight structures with high strength-to-weight and stiffness-to-weight ratios. Honeycombs can be defined as an array of open cells, formed from sheets of suitable material, bonded together at controlled intervals and then expanded to form hexagonal cells. However, recent developments resulted into new alternatives like cellular core structures such as the case of cork. Cork has an alveolar cellular structure similar to that of a honeycomb, and its cells are mostly formed by suberin, lignin and cellulose. Although it seems that natural cork has a poor mechanical behavior when compared with other types of core materials, such as synthetic foams, for some specific applications, cork can actually compete with these materials. Its low thermal conductivity combined with a reasonable compressive strength makes it an excellent material for thermal insulation purposes as well as for applications in which compressive loads are present.
The work herein presented aims to study the feasibility of implementing cork, more specifically the NL20 cork agglomerate fabricated by Amorim Cork Composites, as the core material of sandwich structures with aluminum face sheets (Aalco 5754) by thermally characterizing nine circular sandwich panel samples through experimental tests. Taking into account the enormous challenges imposed by the global stake-holders of drastically reducing (75% per passenger/km) the environmental impact, such as the CO2 emissions associated to the current manufacturing, as well as the operational and maintenance technologies of the various ways of transport, it becomes paramount that aeronautical industry starts incorporating a high amount of recyclable components, in addition to being lighter. Therefore, one of the key objectives of this study is to lower the weight of the samples whilst maintaining their thermal characteristics by drilling different hole patterns into their cork cores. The core configurations differ in hole shape, diameter and depth so that their impact could be assessed. However, a uniform sample is included which served as the reference model for all others. The impact of the core´s mass regarding the component´s insulating ability was also investigated. All samples, which are thermally insulated on the sides in order to ensure one dimensional heat flow, were heated up to 80°C on the bottom face sheet and their individual insulating ability was determined by the measurement of the temperature at the center of the top face sheet with a contact thermocouple. The temperature distribution on the top face sheets was also recorded by a thermographic infrared camera positioned above the samples. The numerical analysis were carried out by resorting to the finite element code ABAQUS® v6.10-1. The experimental tests had to be performed first so that the experimental convective heat transfer coefficient could be determined and subsequently used in the numerical analysis. Heat transfer through radiation was proven to have very little influence on the results due to the small temperature differences between the samples and the surroundings, thus being practicably negligible.
The conclusions drawn from the comparison between the experimental and the numerical results allow taking an important step towards the adoption of cork as the material of choice for the core of sandwich structures and should serve as basis or reference for future more detailed studies in this area.À medida que o recurso a estruturas sandwich continua a aumentar rapidamente para aplicações que vão desde satélites, aeronaves, navios, automóveis, veículos ferroviários a sistemas de energia eólica e construção de pontes (mencionando apenas alguns), estruturas leves e com resistência elevada tornaram-se indispensáveis para muitas indústrias de alta tecnologia tais como a aeroespacial, civil e de transporte em geral. Sendo assim, a procura de novos materiais tem vindo a aumentar o que por sua vez levou ao aumento da utilização de aplicações de estruturas sandwich de compósitos. A utilização de materiais naturais no lugar de estruturas sintéticas tradicionais permite evitar o uso de óleos e outros produtos de carbono para a fabricação, que caso contrário seriam necessários, resultando assim numa redução de emissões de carbono. Para além de serem renováveis, estes materiais fornecem benefícios por serem biodegradáveis e renováveis. Na sua forma mais simples uma sandwich estrutural é composto por duas faces finas e rígidas e um núcleo leve e espesso colocado entre as mesmas. As propriedades de interesse primário para os materiais do núcleo podem ser resumidas da seguinte forma: baixa densidade, módulo de corte elevado, resistência ao corte elevada, rigidez elevada na direção normal às faces e boas características isolantes tanto termicamente como acusticamente. Os materiais de núcleo frequentemente usados são espumas, balsa e estruturas em forma de favo de abelha, que consistem em estruturas superleves com elevadas razões de resistência-peso e rigidez-peso. A configuração favo de abelha pode ser definida como sendo uma matriz de células abertas, formadas a partir de folhas de materiais apropriados, ligadas entre si em intervalos controlados e depois expandidos em ordem a formar células hexagonais. No entanto, desenvolvimentos recentes resultaram em novas alternativas, tais como estruturas de núcleo celular que é o caso da cortiça. A cortiça tem uma estrutura celular alveolar similar ao da configuração de favo de abelha e as suas células são principalmente compostas por suberina, lenhina e celulose. Embora pareça que cortiça natural tenha um fraco comportamento mecânico quando comparado a outros tipos de materiais de núcleo, tais como espumas sintéticas, para algumas aplicações específicas, a cortiça consegue mesmo competir com estes materiais. A sua baixa condutividade térmica combinada com a sua resistência à compressão razoável torna a cortiça um excelente material para propósitos de isolamento térmico como também para aplicações em que estão presentes cargas de compressão. O trabalho aqui apresentado visa estudar a viabilidade de implementar cortiça, mais especificamente o aglomerado de cortiça NL20 fabricado por Amorim Cork Composites, como o material de núcleo de estruturas sandwich com faces de alumínio (Aalco 5754) caracterizando termicamente nove provetes de painéis sandwich circulares através de ensaios experimentais. Tendo em conta os desafios enormes impostos pelos stake-holders globais de reduzir drasticamente (75% por passageiro/km) o impacto ambiental, tais como as emissões de CO2, associadas às tecnologias de fabricação, bem como de operação e manutenção atuais dos vários tipos de transporte, torna-se fundamental que a indústria aeronáutica começa por incorporar uma quantidade elevada de componentes recicláveis, para além de mais leves. Sendo assim, um dos objetivos chave deste estudo é reduzir o peso dos provetes mantendo as suas características térmicas ao aplicar diferentes padrões de furo nos seus núcleos de cortiça. Os configurações de núcleo diferem em forma do furo, diâmetro e profundidade de forma a que a influência destes fatores pudesse ser estudada. No entanto, é incluído um provete uniforme que irá servir de modelo de referência para os restantes. O efeito que a massa de cortiça tem na capacidade isolante também foi estudada. Estes provetes, todos eles isolados termicamente lateralmente de forma a assegurar o fluxo de calor unidimensional, foram aquecidos a 80°C na face inferior e a sua capacidade isolante individual foi determinada através da medição da temperatura no centro da face superior com um termopar de contacto. A distribuição de temperatura nas faces superiores também foi registada através de uma câmara termográfica de infravermelhos posicionada acima dos provetes. As análises numéricas foram realizadas recorrendo ao código de elementos finitos ABAQUS® v6.10-1. Os ensaios experimentais tiveram que ser realizados em primeiro de forma a determinar o coeficiente convectivo experimental para posteriormente ser usado nas análises numéricas. A transferência de calor através de radiação foi provada como tendo muito pouca influência nos resultados devido às diferenças de temperatura reduzidas entre os provetes e a vizinhança, pelo que é praticamente desprezável. As conclusões tiradas a partir da comparação entre os resultados experimentais e numéricos permitem dar um passo importante no sentido da adoção de cortiça como o material de seleção para o núcleo de estruturas sandwich e deverão servir como base ou referência para estudos futuros mais detalhados nesta área.
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Sousa, Laura Raquel Lourenço de. « Estudo da atenuação sonora provocada por coberturas verdes ». Master's thesis, 2017. http://hdl.handle.net/10316/83266.
Texte intégralRésumé :
Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e TecnologiaHá vários séculos que a integração de coberturas verdes como solução construtiva é uma realidade. Tal mostra-se uma mais valia, num mundo cada vez mais preocupado com a sustentabilidade. Estas apresentam vários benefícios ambientais, económicos e sociais. De entre os benefícios ambientais têm sido evidenciados o aumento da biodiversidade urbana, o controlo da temperatura urbana (mitigação da ilha de calor), o controlo e gestão de águas pluviais, aumento da produção de oxigénio, o decréscimo da concentração de dióxido de carbono e a diminuição do ruído ambiente. Esta dissertação insere-se num estudo que pretende incorporar aglomerado de cortiça expandida (ICB) para substituição da camada de isolamento térmico e dos elementos de drenagem e retenção de água utilizados nos sistemas de coberturas verdes tradicionais. No presente trabalho, estudou-se o isolamento sonoro a sons de condução aérea conferida por uma cobertura verde com isolamento térmico convencional do tipo XPS e comparou-se com o obtido numa cobertura verde com isolamento de aglomerado de cortiça expandida. Foram realizados ensaios em câmaras acústicas verticais e mediu-se o isolamento sonoro à medida que iam sendo colocadas as várias camadas constituintes da cobertura verde. Adicionalmente, avaliou-se a capacidade de atenuação sonora de ruído ambiente exterior conferida pelo tapete vegetal da cobertura verde. Simulou-se o ambiente exterior numa câmara anecoica, colocando o tapete vegetal numa estrutura elevada acima do pavimento. A atenuação sonora do ruído ambiente será dependente das capacidades de absorção sonora do tapete vegetal. Esta propriedade caraterizou-se através da medição do coeficiente de absorção sonora dos tapetes vegetais numa câmara reverberante.
For several centuries the integration of green roofs as a constructive solution has become a reality. This shows an added value, in a world increasingly concerned with sustainability. These have several environmental, economic and social benefits. Among the environmental benefits, there has been an increase in urban biodiversity, urban temperature control (heat island mitigation), rainwater management and management, increased oxygen production, decreased carbon dioxide concentration and the reduction of ambient noise.This dissertation is part of a study that intends to incorporate expanded cork agglomerate (ICB) to replace the thermal insulation layer and drainage and water retention elements used in traditional green roofing systems. In the present work, was studied the sound insulation to air conduction sounds conferred by a green cover with conventional thermal insulation of type XPS and compared with that obtained in a green cover with expanded cork agglomerate insulation. Tests were performed on vertical acoustic chambers and the sound insulation was measured as the various constituent layers of the green roof were placed. In addition, the sound attenuation capacity of external ambient noise was assessed by the green roof carpet. The outdoor environment was simulated in an anechoic chamber, placing the vegetable mat in a raised structure above the pavement. Sound attenuation of ambient noise will be dependent on the sound absorption capabilities of the vegetable carpet. This property was characterized by measuring the sound absorption coefficient of the plant carpets in a reverberant chamber.
Outro - A presente dissertação teve o apoio do Portugal 2020 através do Programa Operacional Competitividade e Internacionalização no âmbito dos projetos “GreenUrbanLiving (POCI-01- 0247-FEDER-003393)” e “Concepção e caracterização de coberturas verdes e fachadas vivas construídas com sistemas estruturados em cortiça natural expandida (POCI-01-0145-FEDER- 016852 e PTDC/ECM-COM/5251/2014)”.
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Quintas, Sara Cristina da Silva. « Avaliação do desempenho ambiental do aglomerado negro de cortiça ». Master's thesis, 2015. http://hdl.handle.net/1822/40520.
Texte intégralRésumé :
Dissertação de mestrado integrado em Engenharia CivilAs soluções construtivas e os métodos utilizados na indústria da construção são responsáveis por elevados impactes ambientais. Atualmente, o custo associado às soluções construtivas é ainda o fator de maior peso na decisão final. Contudo, torna-se claro o crescente interesse por parte do setor da mudança de paradigma no setor através da procura de melhores soluções. De modo a facilitar essa escolha por parte dos compradores, de entre a variedade de materiais análogos, é necessária a análise e quantificação dos impactes associados a cada produto. De entre várias ferramentas que surgem, destaca-se, neste trabalho, a Declaração Ambiental do Produto (DAP). A DAP é um documento complementar de informação do produto ao longo do ciclo de vida através de um conjunto de categorias de impacte ambiental específicas. O desenvolvimento da DAP é produzida de acordo com a norma NP 15804 e a RCP (Regras Categorias de Produto) para materiais de construção. Este trabalho encontra-se orientado para um estudo do comportamento ambiental de um dos materiais de isolamento fabricados e utilizados no isolamento de edifícios em Portugal: o aglomerado negro de cortiça (ICB). O ICB deriva de uma matéria-prima totalmente natural e renovável, a cortiça (falca). Cuja extração resulta das operações de limpeza e manutenção dos sobreiros. É um produto de isolamento nobre, reconhecido pela sua durabilidade e estabilidade, um produto 100% natural, eficiente e reciclável. A finalidade da concretização do presente trabalho prende-se com o estudo do desempenho ambiental do aglomerado negro de cortiça. Apesar de ao longo do trabalho se referir ao desenvolvimento da DAP, os resultados apresentados apenas poderão ser considerados uma avaliação do desempenho ambiental do produto de acordo com as normas em vigor, uma vez que, tendo por base a sua génese num trabalho de investigação, não foram verificados por uma entidade independente.
The building solutions and the methods used in the construction industry are responsible for high potential environmental impacts. Nowadays, the building solutions cost is still the most important parameter in the final decision. However, it becomes clear the growing interest in changing the paradigm of the sector through the development of improved solutions. Therefore, to facilitate this choice, among a variety of similar materials, it is necessary to create the necessary mechanisms that allow analysing and quantifying the potential environmental impacts of different products. Among the multiple tools that are being developed, this work is focused in the Environmental Product Declarations (EPD). EPD is a supplementary product information document that gathers the potential life-cycle impacts, based in a set of standardized impact categories, of a product. For building products, the development of an EPD is carried out in accordance with NP 15804 standard and Product Category Rules (PCR). This research is aimed at studying the environmental proprieties one of one of the insulation materials produced and used for building insulation in Portugal: the black agglomerated cork (ICB). The ICB comes from a raw material totally natural and renewable: cork. The specific cork used in ICB results from the cleaning and maintenance of the national cork oak forest. It is a product of noble isolation, recognized by its durability and stability, 100% natural, efficient and recyclable. The objective of the present work is to study the environmental performance of the black agglomerated cork insulation board. Although along this work it is mentioned the development of an EPD, the presented results can only be considered as an assessment of the environmental performance of the product according to the applicable standards, since they were not verified by a third party organization.
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Cortês, Andreia Sofia Borges. « Design and development of an innovative green vertical system ». Doctoral thesis, 2021. http://hdl.handle.net/10316/95296.
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PhD thesis in Civil Engineering, Constructions, submitted to Department of Civil Engineering of the Faculty of Sciences and Technology of the University of Coimbra.Urban centres are facing several challenges resulting from their quick expansion and from climate change. As a consequence, some areas have been experiencing flash floods, degradation of air quality, and an increase in temperatures. Buildings also represent a high burden in terms of greenhouse gas emission and energy consumption. It is therefore extremely important to invest in finding solutions that could help to mitigate the effects of some of these problems. In this context, the European Commission has encouraged countries and regions to adopt nature-based solutions, particularly green vertical systems (GVSs), that can improve daily living and environmental conditions. Green vertical systems are construction solutions that use vegetation to cover a building surface. The benefits that have been attributed to them include an improvement in buildings’ thermal insulation, the mitigation of the urban heat island effect, better air quality, the restoration of urban biodiversity, and the support of rainwater management. However, several questions have also been raised concerning the sustainability of these solutions. The use of materials with high environmental burdens and the high irrigation and maintenance needs of such systems are being pointed out as key aspects. Additionally, the design and implementation of GVSs can be much more complex than other green infrastructure since the plants and/or growing media must be fixed to a vertical surface. The main goal of this research work was to design and develop an innovative green vertical system, with improved environmental performance over its life-cycle. The expanded cork agglomerate was the main material. Thermal insulation and water retention are two of the characteristics recognized in this natural material that turned it into a suitable option. Tests were initially performed to quantify the water retention capacity and drainage capability of the insulation cork boards (ICB). The results showed that the material allows a suitable moistening and a good retention capacity, and at the same time it can quickly drain the excess water. A new ICB module was then designed, based on a set of environmental and functional aspects discussed beforehand. The ICB modules then underwent a series of mechanical tests to evaluate the behaviour of the proposed solution in wet conditions and after wetting-drying cycles. These experiments also intended to help to choose the most suitable material density to use in the new GVS. The results showed that the medium density ICB modules (140–160 kg/m3) fully meet the environmental and functional requirements, and are therefore an appropriate choice. Afterwards, a real-scale prototype was built, consisting of four façades (facing north, south, east, and west) and two plant species (Thymus pulegioides and Festuca glauca) were selected for the system. The prototypes were monitored for one year to check the coverage area, carbon sequestration capacity, and thermal behaviour. The results showed that the system and the plant species performed well. The overall environmental profile of the system was evaluated through a life-cycle study and it was found that the new modular living wall can be an eco-friendly choice, contributing especially to mitigate global warming.
Os centros urbanos enfrentam diversos desafios decorrentes da sua rápida expansão e das alterações climáticas. Como resultado, algumas destas áreas têm vindo a deparar-se com inundações repentinas, uma degradação da qualidade do ar e um aumento da temperatura. Os edifícios representam também uma grande preocupação pelas elevadas emissões de gases com efeito de estufa e pelo elevado consumo energético. Considerando todos estes aspetos, torna-se extremamente importante investir na procura de soluções que possam ajudar a mitigar alguns dos efeitos destes problemas. Neste contexto, a Comissão Europeia tem vindo a incentivar países e regiões a adotarem soluções baseadas na natureza, nomeadamente as fachadas verdes, que têm a capacidade de melhorar a qualidade de vida das populações e as condições ambientais. As fachadas verdes são soluções construtivas que utilizam a vegetação para recobrir a fachada de um edifício. Os benefícios que lhes têm sido atribuídos incluem uma melhoria do isolamento térmico dos edifícios, a mitigação do efeito ilha de calor urbana, uma melhoria da qualidade do ar, a recuperação da biodiversidade urbana e o apoio à gestão das águas pluviais. No entanto, várias questões têm também surgido em relação à sustentabilidade destas soluções. A utilização de materiais com elevados impactes ambientais e as elevadas necessidades de irrigação e manutenção têm vindo a ser apontados como aspetos importantes. Além disso, a conceção e a implementação das fachadas verdes podem também tornar-se tarefas muito complexas quando comparadas com as de outras infraestruturas verdes uma vez que, no caso das fachadas verdes as plantas e/ou os meios de cultivo têm de ser fixados numa superfície vertical. O objetivo principal deste trabalho de investigação foi conceber e desenvolver uma solução de fachada verde inovadora com um melhor desempenho ambiental ao longo do seu ciclo de vida. Para tal, foi utilizado como material principal o aglomerado de cortiça expandida. A capacidade de isolamento térmico e de retenção de água são duas das características reconhecidas a este material natural que o tornaram numa opção adequada. Inicialmente foram realizados testes para quantificar a capacidade de retenção de água e de drenagem das placas de aglomerado de cortiça expandida (ICB). Os resultados mostraram que o material permite um adequado humedecimento e uma boa retenção, demonstrando simultaneamente a capacidade de escoar de forma rápida o excesso de água. A conceção de um novo módulo de ICB foi, então, realizada com base num conjunto de aspetos ambientais e funcionais discutidos anteriormente. Os módulos de ICB foram posteriormente submetidos a uma série de testes mecânicos para avaliar o comportamento da solução proposta em condições húmidas e após os ciclos de humedecimento-secagem. Esta campanha experimental teve também como objetivo ajudar na escolha da densidade do material mais adequada para usar no novo sistema de fachada verde. Os resultados mostraram que os módulos de ICB de média densidade (140–160 kg/m3) cumprem totalmente os requisitos ambientais e funcionais, mostrando-se uma escolha adequada. Posteriormente, foi construído um protótipo em escala real constituído por quatro fachadas (orientadas a norte, sul, este e oeste) e foram selecionadas duas espécies de plantas (Thymus pulegioides e Festuca glauca) para integrarem o sistema. Os protótipos foram monitorizados durante um ano em termos da área de cobertura, do sequestro de carbono e do comportamento térmico. Os resultados revelaram um bom desempenho do sistema e das espécies vegetativas selecionadas. O perfil ambiental e global do sistema foi avaliado por meio de um estudo de ciclo de vida. Os resultados mostraram que a nova fachada verde pode ser uma escolha ecologicamente correta, contribuindo principalmente para mitigar o aquecimento global.
Livres sur le sujet "Cork agglomerates"
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Parker, Philip M. The World Market for Agglomerated Cork and Articles Thereof : A 2007 Global Trade Perspective. ICON Group International, Inc., 2006.
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The World Market for Agglomerated Cork and Articles Thereof : A 2004 Global Trade Perspective. Icon Group International, Inc., 2005.
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The World Market for Agglomerated Cork Blocks, Plates, Sheets, Strip, Tiles, and Solid Cylinders : A 2004 Global Trade Perspective. Icon Group International, Inc., 2005.
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Parker, Philip M. The World Market for Agglomerated Cork Blocks, Plates, Sheets, Strip, Tiles, and Solid Cylinders : A 2007 Global Trade Perspective. ICON Group International, Inc., 2006.
Trouver le texte intégralChapitres de livres sur le sujet "Cork agglomerates"
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Yay, Ömer, Mahdi Hasanzadeh, Seyid Fehmi Diltemiz et Selim Gürgen. « Cork Agglomerates in Acoustic Insulation ». Dans Cork-Based Materials in Engineering, 17–30. Cham : Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-51564-4_3.
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Kunt, Gökhan, et Selim Gürgen. « Penetration Resistance of Laminated Composites Including Cork Agglomerates ». Dans Green Energy and Technology, 19–31. Cham : Springer Nature Switzerland, 2024. https://doi.org/10.1007/978-3-031-72882-2_2.
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Peón, Samuel Maza, Ramon Miralbes et Mario Maza Frechin. « Experimental Study of the Influence of Strain-Rate on the Mechanical Properties of Cork and Its Agglomerates ». Dans Advances in Design Engineering IV, 588–97. Cham : Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-51623-8_57.
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Le Barbenchon, Louise, Jean-Benoît Kopp, Jérémie Girardot et Philippe Viot. « Dynamic Mechanical Behavior of Reinforced Cork Agglomerate ». Dans Dynamic Behavior of Materials, Volume 1, 209–13. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-30021-0_36.
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Le Barbenchon, Louise, Jean-Benoît Kopp, Jérémie Girardot et Philippe Viot. « Strain-Rate Effect on the Deformation Mechanisms of Agglomerated Cork ». Dans Dynamic Behavior of Materials, Volume 1, 201–7. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-30021-0_35.
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Sasso, Marco, Fabrizio Sarasini, Gianluca Chiappini, Edoardo Mancini et Jacopo Tirillò. « Evaluation of Stress Equilibrium in Dynamic Tests on Agglomerated Cork ». Dans Dynamic Behavior of Materials, Volume 1, 235–41. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-62956-8_36.
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Pereira, Helena. « Cork agglomerates and composites ». Dans Cork, 289–303. Elsevier, 2007. http://dx.doi.org/10.1016/b978-044452967-1/50015-7.
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Tarasov, Andrii, Miguel Cabral, Christophe Loisel, Paulo Lopes, Christoph Schuessler et Rainer Jung. « State-of-the-Art Knowledge about 2,4,6-Trichloroanisole (TCA) and Strategies to Avoid Cork Taint in Wine ». Dans Grapes and Wine [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.103709.
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Cork stoppers have been used for many centuries to seal wine in various vessels. Therefore, corks have become a traditional part of wine packaging in many countries and still play an important role for the entire wine industry. Nowadays, there is a wide option of bottle cork stoppers on the market, such as natural corks, agglomerated and technical stoppers (1 + 1), etc. These cork closures have a number of advantages, including positive sustainable and ecological aspects. Natural cork material can also be responsible for cork taint, which imparts musty/moldy or wet cardboard off-odors to the wine. However, corks are not the only source of cork taint in wine, as will be shown in the present chapter. Over the past decades, a number of compounds have been detected that can contribute to the cork taint. Among them, haloanisoles play a major role, in particular 2,4,6-trichloroanisole (TCA), which has been shown to be responsible for 50–80% or more of musty defect cases in wine. Currently, the cork and wine industries have developed a number of tools and technologies to effectively prevent cork tait in wine or to remove it if the wine is already contaminated. These practical as well as analytical questions about the TCA defects are the subject of the actual chapter.
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Dizdar, Senad, et Amogh Vedantha Krishna. « Microstructural and Mechanical Properties of Polylactic Acid/Tin Bronze Tensile Strength Bars Additive Manufactured by Fused Deposition Modelling ». Dans Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220175.
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Tensile stress bar samples have been additive manufactured by fused deposition modelling (FDM) route by using polylactic acid (PLA)/tin bronze filament, thermal de-binding and air sintering. The samples reach sintered density of 7.42 g/cm3 or 85% of the relative density of the continuously casted CuSn10 reference. Tensile stress testing of the samples shows rather moderate mechanical properties, about half yield strength and one third maximal strength, elongation and hardness of the reference. Increase in the sample core density and elimination of large, agglomerated pores may result in largest improvement of the mechanical properties.
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Afonso, F. « Potential for the design of an energy saving facade system using agglomerated cork : Implications in subtropical climates ». Dans Sustainable Buildings and Structures : Building a Sustainable Tomorrow, 185–91. CRC Press, 2019. http://dx.doi.org/10.1201/9781003000716-24.
Texte intégralActes de conférences sur le sujet "Cork agglomerates"
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« A Cost-Effective Methodology to Perform Customized Moulding of Cork Agglomerates ». Dans Cork Science and its Applications. Materials Research Forum LLC, 2017. http://dx.doi.org/10.21741/9781945291418-6.
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« Thermal Conductivity of Agglomerate Cork ». Dans Cork Science and its Applications. Materials Research Forum LLC, 2017. http://dx.doi.org/10.21741/9781945291418-1.
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« Crashworthiness of Agglomerated Cork Under the Influence of Extremely Low and High Temperatures ». Dans Cork Science and its Applications II. Materials Research Forum LLC, 2019. http://dx.doi.org/10.21741/9781644900413-7.
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Hendraningrat, L., N. A. Ramli, L. Riyanto, S. Zainal, N. A. Shafie, S. Baharuddin, P. K. Rajasekaran, K. A. Mahadi, M. I. Zubir et S. K. H. Shafie. « Integrated Solution to Tackle Sand Production Using Inhouse Sand Agglomeration Technology : A Pilot in Offshore Malaysian Oilfield ». Dans SPE Annual Technical Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/214845-ms.
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Abstract Several oil fields in the Malaysian oilfields have experienced sand production issues, which caused a reduction in production. Moreover, if artificial lift systems such as ESP is installed, it can lead to frequent failures, which will have a significant impact on cost due to pump downtime. Mechanical solutions that are commonly used, such as sand screen and gravel packs, are suboptimal because they decrease inflow area and make optimization activities difficult. This paper describes an integrated solution that employs inhouse sand agglomeration chemical (SAC) technology and mechanical solution to address the sand production problem from laboratory to pilot in an offshore oil well. Extensive laboratory tests confirmed the SAC viability for sand production in Field-S. A pilot well candidate was selected based on a history of frequent well interventions due to sand production in the past, as well as the completeness of core samples, mineralogy data, and fluid samples. The test was conducted with an actual downhole sand sample and a sand screen, while flowrate and pressure were monitored. Produced sand was collected for particle size distribution measurement and scanning electron microscope, static and dynamic thermal stability tests, chemical and agglomerated sand particles were aged at downhole temperature and pressure. During pilot, the SAC was injected near the wellbore, and then a sand screen was installed, with post-injection monitoring. A novel multipolymers chemical concept SAC was proposed, which provides larger agglomerates of grains sands and stronger bond strength between particles, resulting in longer agglomerated sand particle longevity. Meanwhile, the sand screen was installed, and injection was done simply with a bullhead and no squeeze required. After applying SAC in the laboratory, a strong sand agglomeration was observed on the produced sand sample. The SAC can reduce the non-uniformity of agglomerated sand particles, lowering the risk of screen plugging and improving permeability. It also reduces the risk of sand screen plugging and opens more flow channels for hydrocarbon to flow through. This first pilot was successfully executed in a well at Field-S. The knowledge and experience gathered during this first pilot will be utilized as a reference for future replication to other candidates in the Malaysian oilfields with similar issue.
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Castro, António, João P. Cardoso, Luís Filipe Mendes, Pedro Azevedo et João Farinha Mendes. « Pre-heating boiler feedwater for expanded cork agglomerate production using a parabolic trough system ». Dans SolarPACES 2017 : International Conference on Concentrating Solar Power and Chemical Energy Systems. Author(s), 2018. http://dx.doi.org/10.1063/1.5067155.
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Kar, Simanchal, P. P. Bandyopadhyay et S. Paul. « Effect of Arc-Current and Particle Morphology on Fracture Toughness of Plasma Sprayed Aluminium Oxide Coating ». Dans ASME 2017 12th International Manufacturing Science and Engineering Conference collocated with the JSME/ASME 2017 6th International Conference on Materials and Processing. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/msec2017-2993.
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Alumina powder was sprayed on low carbon steel substrate using atmospheric plasma spray process. Two different powders namely crushed and agglomerated powders were used and current was varied to study their effect on fracture toughness. Theoretically, with increase in arc current, melting of ceramic oxide shall increases and in turn dense coating should form. However, it was observed that if the arc power is too high and particle size of the powder being small (∼ 30 μm), the particles tend to fly away from the plasma core. Similarly, particle size distribution and powder morphology also affects the coating properties. Smaller particle should allow more melting resulting in dense coating and agglomerated powder allows flowability as well as better coating efficiency. Conversely, smaller particles tend to fly away from the plasma making the process difficult while the agglomerated particles showed a bimodal structure marked by presence of unmelted region in the splat core. All these factors lead to substantial variation in the fracture toughness of the coating. The present paper attempts to correlate plasma spraying parameters and microstructure of the coating with fracture toughness of the same.
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Gocht, T., W. Kästner, A. Kratzsch et M. Strasser. « Test and Evaluation of a Filtering System for Retention of Fibres in a Coolant Flow After Loss-of-Coolant Accident ». Dans 2012 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icone20-power2012-54078.
Texte intégralRésumé :
In case of an accident the safe heat removal from the reactor core with the installed emergency core cooling system (ECCS) is one of the main features in reactor safety. During a loss-of-coolant accident (LOCA) the release of insulation material fragments in the reactor containment can lead to malfunctions of ECCS. Therefore, the retention of particles by strainers or filtering systems in the ECCS is one of the major tasks. The aim of the presented experimental investigations was the evaluation of a filtering system for the retention of fiber-shaped particles in a fluid flow. The filtering system consists of a filter case with a special lamellar filter unit. The tests were carried out at a test facility with filtering units of different mesh sizes. Insulation material (mineral rock wool) was fragmented to fiber-shaped particles. To simulate the distribution of particle concentration at real plants with large volumes the material was divided into single portions and introduced into the loop with a defined time interval. Material was transported to the filter by the fluid and agglomerated there. The assessment of functionality of the filtering system was made by differential pressure between inlet and outlet of the filtering system and by mass of penetrated particles. It can be concluded that for the tested filtering system no penetration of insulation particles occurred.
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Chan, Kiki, Gladys Olubowale, Levente Diosady et Yu-Ling Cheng. « Attrition of fully hydrogenated soybean oil-coated micronutrient granules during mixing ». Dans 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/iwnz7321.
Texte intégralRésumé :
Fully hydrogenated soybean oil (FHSBO) is a versatile coating material for food and pharmaceutical products. Its neutral taste, oxidative and thermal stability, and hydrophobicity, makes it an ideal physical barrier against moisture and oxygen. As a coating on granular foods, FHSBO also prevents undesirable interactions between the coated granules and other components in the product matrix. However, during mixing processes, impact from the mixer impellers and abrasion from the other ingredients can lead to chipping or wear on FHSBO coatings, which lowers the quality of the finished products. Unfortunately, existing efforts to maintain the integrity of FHSBO-coated granules are limited to trial-and-error adjustments to processing parameters and product formulations because attrition mechanisms are not well understood. Thus, the objective of this study was to quantify the influence of processing parameters on the attrition of FHSBO-coated granules. Specifically, we examined granule attrition in FHSBO-coated micronutrient premix during the manufacturing process for fortified bouillon cubes. Each micronutrient premix granule comprises an agglomerated micronutrient (i.e., vitamins and minerals) core, a titanium dioxide layer, a hydroxypropyl methylcellulose (HPMC) layer, and an FHSBO coating. The external coating of FHSBO on premix granules stabilizes the vitamins and minerals in fortified foods during storage. In this study, premix granules were subjected to the mixing and coating conditions typical of the bouillon cube manufacturing process, and the degree of core exposure in the granules was measured. Our results show that the abrasion from crystalline ingredients in the bouillon cube matrix and the impact from the mixer impellers during the mixing and coating steps can compromise the FHSBO coating on premix. This study provides insights for improving product quality in edible applications involving fully hydrogenated soybean oil and similar fat coatings.
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Parker, Liam, Matthew McGilvray, David R. H. Gillespie et Geoffrey Jones. « Numerical Simulations of Ice Particle Transport at Representative Turbofan Compressor Conditions ». Dans ASME Turbo Expo 2024 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/gt2024-121461.
Texte intégralRésumé :
Abstract Engine icing threatens compressor operation and service life. Ice crystal ingestion at cruise and descent phases of flight result in smaller, partial melted crystals entering the engine core. Here, crystals can stick to stationary surfaces driven by the presence of a water film, and evaporative and melting heat exchange with the mixed phase crystals. Modelling of the ice crystal cloud conditions is needed to understand threat areas within the core and operating envelope and to provide a reliable basis for ice accretion modelling at solid surfaces. A particle transport model in three-dimensions combining tracking, heat transfer, phase change along with a turbophoresis model is presented for non-spherical mixed phase ice crystals. These present a challenge to model effectively considering the complex and anisotropic geometries of ice crystals. Further, crystals can fragment, melt and agglomerate along the gas path. This affects heat transfer, phase change and ice porosity which will implicate the deposition location and composition. The model is validated against previous altitude icing wind tunnel experiments at LP/IP compressor operating conditions. Measured conditions for ice crystal mass flux provide experimental comparison against particle advection and phase change. Particle advection is modelled using an Euler-Lagrangian approach with two-way mass-energy coupling. Particle turbulent dispersion is modelled using a discrete random walk (DRW) model which is appropriate for flows where particles are primarily inertially-moderated. The model is seen to predict particle cloud mass distribution to within 15% of the experimentally measured total water content (TWC). Particle sizes between 2 μm and 131 μm and are modelled as spheroids. The variation in melt response is investigated relative to particle size and aspect ratio. High aspect ratio particles (AR > 10) result in 5% to 20% phase change augmentation depending on the particle angle of attack. Two way coupling is shown to increase the melt ratio by up to 10% and reduce the total water content by up to 25% compared to one-way coupling. The model provides a framework for compressor stage ice particle transport and deposition in ice crystal icing conditions.
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Tonelli, Chiara. « Abitare domani : sfide e opportunità per la Smart City ». Dans International Conference Virtual City and Territory. Roma : Centre de Política de Sòl i Valoracions, 2014. http://dx.doi.org/10.5821/ctv.7952.
Texte intégralRésumé :
"La nascita dell’agricoltura segna, agli inizi della civiltà, la costituzione delle due più antiche
professioni al mondo: l’agronomo e l’architetto. … L’agronomo in grado di comprendere la
qualità del terreno e sapere come trattare le sementi, e l’architetto in quanto deputato
all’organizzazione creativa del nuovo ambiente umano, ovvero la gestione dello spazio che
racchiude la zona nella quale si concentrano le attività e la vita degli agricoltori”.
Ecco la nascita della città, uno dei tre assi portanti del convegno “Città, Memoria, Gente” in cui
si inseriva la sessione “Architettura, Sostenibilità, Energia” che ho moderato. Senza la città i tre
temi della sessione non avrebbero lo stesso portato. Un casale isolato nella campagna è
un’architettura, è sostenibile e produce la propria energia, almeno quella alimentare per i suoi
abitanti. Ci interessava però mettere a fuoco il meccanismo che unisce gli edifici al loro essere
insieme in un agglomerato che si è fatto città, dove si intessono relazioni umane, dove si creano
condizioni di sostenibilità, dove si consuma ma si può produrre energia. "The birth of agriculture marks the beginning of civilization, the formation of the two oldest
professions in the world: the agronomist and the architect. The agronomist ... able to
understand the quality of the land and to know how to treat the seeds, and the architect as
deputy of the creative organization of the new human environment, such as the management of
the space that encloses the area where activities and the lives of farmers are concentrated"
(Sergio Di Cori Modigliani, “La narrativa esistenziale di Territorio zero”, in Territorio Zero, per
una società a emissioni zero e chilometri zero, a cura di Livio De Santoli e Angelo Consoli,
Minimum fax, Roma, 2013).
Here it is the birth of the “Cities”, one of the three themes of the conference "Cities, Memory,
People" where the session "Architecture, Sustainability, Energy ", which I moderated, was.
Without the city the three themes of the session would not have brought the same. An isolated
house in the countryside is an architecture, it is sustainable and produces its own energy, at
least feed its inhabitants. We were interested, however, to focus on the mechanism that links
the buildings to their being together in a cluster that has made the city where human relations
weave, where sustainable conditions could be created, where it is possible to consume as well
to produce energy.
Rapports d'organisations sur le sujet "Cork agglomerates"
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Coplin, David, Isaac Barash et Shulamit Manulis. Role of Proteins Secreted by the Hrp-Pathways of Erwinia stewartii and E. herbicola pv. gypsophilae in Eliciting Water-Soaking Symptoms and Initiating Galls. United States Department of Agriculture, juin 2001. http://dx.doi.org/10.32747/2001.7580675.bard.
Texte intégralRésumé :
Many bacterial pathogens of plants can inject pathogenicity proteins into host cells using a specialized type III secretion system encoded by hrpgenes. This system deliver effector proteins, into plant cells that function in both susceptible and resistant interactions. We have found that the virulence of Erwinia stewartii(Es; syn. Pantoea stewartii) and Erwinia herbicola pv. gypsophilae (Ehg, syn. Pantoea agglomerans), which cause Stewart's wilt of corn and galls on Gypsophila, respectively, depends on hrpgenes. The major objectives of this project were: To increase expression of hrpgenes in order to identify secreted proteins; to identify genes for proteins secreted by the type-III systems and determine if they are required for pathogenicity; and to determine if the secreted proteins can function within eukaryotic cells. We found that transcription of the hrp and effector genes in Es and Ehg is controlled by at least four genes that constitute a regulatory cascade. Environmental and/or physiological signaling appears to be mediated by the HrpX/HrpY two component system, with HrpX functioning as a sensor-kinase and HrpY as a response regulator. HrpYupregulateshrpS, which encodes a transcriptional enhancer. HrpS then activates hrpL, which encodes an alternate sigma factor that recognizes "hrp boxes". All of the regulatory genes are essential for pathogenicity, except HrpX, which appears only to be required for induction of the HR in tobacco by Es. In elucidating this regulatory pathway in both species, we made a number of significant new discoveries. HrpX is unusual for a sensor-kinase because it is cytoplasmic and contains PAS domains, which may sense the redox state of the bacterium. In Es, a novel methyl-accepting protein may function upstream of hrpY and repress hrp gene expression in planta. The esaIR quorum sensing system in Es represses hrp gene expression in Es in response to cell-density. We have discovered six new type III effector proteins in these species, one of which (DspE in Ehg and WtsE in Es) is common to both pathogens. In addition, Es wtsG, which is a homolog of an avrPpiB from P. syringae pv. pisi, and an Ehg ORF, which is a homolog of P. syringae pv. phaseolicola AvrPphD, were both demonstrated to encode virulence proteins. Two plasmidborne, Ehg Hop proteins, HsvG and PthG, are required for infection of gypsophilia, but interestingly, PthG also acts as an Avr elicitor in beets. Using a calmodulin-dependent adenylate cyclase (cyaA) reporter gene, we were successful in demonstrating that an HsvG-CyaA fusion protein can be transferred into human HeLa cells by the type-III system of enteropathogenic E. coli. This is a highly significant accomplishment because it is the first direct demonstration that an effector protein from a plant pathogenic bacterium is capable of being translocated into a eukaryotic cell by a type-III secretion system. Ehg is considered a limiting factor in Gypsophila production in Israel and Stewart’s Wilt is a serious disease in the Eastern and North Central USA, especially on sweet corn in epidemic years. We believe that our basic research on the characterization of type III virulence effectors should enable future identification of their receptors in plant cells. This may lead to novel approaches for genetically engineering resistant plants by modifying their receptors or inactivating effectors and thus blocking the induction of the susceptible response. Alternatively, hrp gene regulation might also provide a target for plant produced compounds that interfere with recognition of the host by the pathogen. Such strategies would be broadly applicable to a wide range of serious bacterial diseases on many crops throughout the USA and Israel.
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Coplin, David L., Shulamit Manulis et Isaac Barash. roles Hrp-dependent effector proteins and hrp gene regulation as determinants of virulence and host-specificity in Erwinia stewartii and E. herbicola pvs. gypsophilae and betae. United States Department of Agriculture, juin 2005. http://dx.doi.org/10.32747/2005.7587216.bard.
Texte intégralRésumé :
Gram-negative plant pathogenic bacteria employ specialized type-III secretion systems (TTSS) to deliver an arsenal of pathogenicity proteins directly into host cells. These secretion systems are encoded by hrp genes (for hypersensitive response and pathogenicity) and the effector proteins by so-called dsp or avr genes. The functions of effectors are to enable bacterial multiplication by damaging host cells and/or by blocking host defenses. We characterized essential hrp gene clusters in the Stewart's Wilt of maize pathogen, Pantoea stewartii subsp. stewartii (Pnss; formerly Erwinia stewartii) and the gall-forming bacterium, Pantoea agglomerans (formerly Erwinia herbicola) pvs. gypsophilae (Pag) and betae (Pab). We proposed that the virulence and host specificity of these pathogens is a function of a) the perception of specific host signals resulting in bacterial hrp gene expression and b) the action of specialized signal proteins (i.e. Hrp effectors) delivered into the plant cell. The specific objectives of the proposal were: 1) How is the expression of the hrp and effector genes regulated in response to host cell contact and the apoplastic environment? 2) What additional effector proteins are involved in pathogenicity? 3) Do the presently known Pantoea effector proteins enter host cells? 4) What host proteins interact with these effectors? We characterized the components of the hrp regulatory cascade (HrpXY ->7 HrpS ->7 HrpL ->7 hrp promoters), showed that they are conserved in both Pnss and Fag, and discovered that the regulation of the hrpS promoter (hrpSp) may be a key point in integrating apoplastic signals. We also analyzed the promoters recognized by HrpL and demonstrated the relationship between their composition and efficiency. Moreover, we showed that promoter strength can influence disease expression. In Pnss, we found that the HrpXY two-component signal system may sense the metabolic status of the bacterium and is required for full hrp gene expression in planta. In both species, acyl-homoserine lactone-mediated quorum sensing may also regulate epiphytic fitness and/or pathogenicity. A common Hrp effector protein, DspE/WtsE, is conserved and required for virulence of both species. When introduced into corn cells, Pnss WtsE protein caused water-soaked lesions. In other plants, it either caused cell death or acted as an Avr determinant. Using a yeast- two-hybrid system, WtsE was shown to interact with a number of maize signal transduction proteins that are likely to have roles in either programmed cell death or disease resistance. In Pag and Pab, we have characterized the effector proteins HsvG, HsvB and PthG. HsvG and HsvB are homologous proteins that determine host specificity of Pag and Pab on gypsophila and beet, respectively. Both possess a transcriptional activation domain that functions in yeast. PthG was found to act as an Avr determinant on multiple beet species, but was required for virulence on gypsophila. In addition, we demonstrated that PthG acts within the host cell. Additional effector genes have been characterized on the pathogenicity plasmid, pPATHₚₐg, in Pag. A screen for HrpL- regulated genes in Pnsspointed up 18 candidate effector proteins and four of these were required for full virulence. It is now well established that the virulence of Gram-negative plant pathogenic bacteria is governed by Hrp-dependent effector proteins. However; the mode of action of many effectors is still unresolved. This BARD supported research will significantly contribute to the understanding of how Hrp effectors operate in Pantoea spp. and how they control host specificity and affect symptom production. This may lead to novel approaches for genetically engineering plants resistant to a wide range of bacterial pathogens by inactivating the Hrp effectors with "plantabodies" or modifying their receptors, thereby blocking the induction of the susceptible response. Alternatively, innovative technologies could be used to interfere with the Hrp regulatory cascade by blocking a critical step or mimicking plant or quorum sensing signals.