<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Aliphatic bio-oils from corks: A Py–GC/MS study</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Analytical and Applied Pyrolysis</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2014</style></year></dates><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Cork samples from Betula pendula, Quercus suber and Quercus cerris were submitted to Py–GC–MS/FID at temperatures between 550°C and 900°C and the pyrolysis-derived compounds (py-products) were identified and quantified. Corks were compared with wood samples. Py-products include suberin, lignin and carbohydrates derivatives. Suberin py-products are dominated by unsaturated aliphatics. Corks pyrolysis yield and composition were dramatically influenced by temperature in contrast to wood that showed stable results across temperatures. At 850–900°C the peaks area of cork pyrograms were approximately two times higher than at 550°C, for which yield was about half of the woods, and cork py-products were dominated by suberin-derived short chain aliphatics, namely 1-alkenes, while at 550°C composition was dominated by lignin derivatives. Lignin and carbohydrate derived products decreased dramatically over 750°C while the opposite was observed for unsaturated aliphatics. Cork materials show a high potential as feedstock for production of aliphatic-rich pyrolytic biofuels or as a source of olefins.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Şen, Ali</style></author><author><style face="normal" font="default" size="100%">Van den Bulcke, Jan</style></author><author><style face="normal" font="default" size="100%">Defoirdt, Nele</style></author><author><style face="normal" font="default" size="100%">Van Acker, Joris</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Thermal behaviour of cork and cork components</style></title><secondary-title><style face="normal" font="default" size="100%">Thermochimica Acta</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">DSC</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus cerris</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">suberin</style></keyword><keyword><style  face="normal" font="default" size="100%">TGA</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2014///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S0040603114000902</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">582</style></volume><pages><style face="normal" font="default" size="100%">94 - 100</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Thermal behaviour of cork and cork chemical components was studied with coupled differential scanning calorimetry-thermogravimetrical analysis (DSC-TGA) in order to gain insight into the role of the chemical components on the thermal degradation of cork. Cork samples of Turkey oak (Quercus cerris) and cork oak (Quercus suber) were chemically treated to selectively remove inorganic material, extractives and suberin, to allow characterization of klason lignin and methanolysis-depolymerized suberin. Since Q. cerris cork granulates contain phloemic impurities, phloem from Q. cerris bark was also subjected to the same treatments as cork. The thermal decomposition of both cork species is similar, starting above 200°C and increasing with increasing temperature until ashing at approximately 485°C. TGA curves of both corks are almost identical but a detailed view on the differential thermogravimetry (DTG) and DSC curves shows that the two materials differ from each other. Two exothermal devolatilization and char combustion reactions occur, peaking at approximately 313°C and 445°C. These peak temperatures shift to lower temperatures in suberin-free and extractive-free corks giving evidence of the heat retarding effect of suberin and extractives and possible catalytic effect of inorganics in desuberinised cork. Phloem thermal degradation is similar to that of cork although exothermal peak temperatures are higher. Phloem-containing Q. cerris cork granulates thus show clear potential for high temperature applications.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Anjos, Ofélia</style></author><author><style face="normal" font="default" size="100%">Rodrigues, Cátia</style></author><author><style face="normal" font="default" size="100%">Morais, José</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Effect of Density on the Compression Behaviour of Cork</style></title><secondary-title><style face="normal" font="default" size="100%">Materials &amp; Design</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Compression</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Density</style></keyword><keyword><style  face="normal" font="default" size="100%">Dimensional recovery</style></keyword><keyword><style  face="normal" font="default" size="100%">Young’s modulus</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S0261306913006663</style></url></web-urls></urls><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The compression properties of cork were studied for samples of different density. The densities were grouped into three classes: low density (0.13-0.15), mid density (0.15-0.19) and high density (0.19-0.25). The porosity of the cork samples increased from the low to the high density class, with porosity coefficients of 5.1%, 6.9% and 9.4% respectively. The difference in the porosity was associated with structural features, namely the presence of thick walled cork cells and the presence of lignified cells lining the pores. The stress-strain curves were similar for all cases, showing an elastic compression up to a yield point of about 5% strain, followed by a plateau with a small slope. The cork strength was higher in the radial direction than in the other directions. The density influenced the compression such that the corks with high density presented higher stiffness in compression in three directions: Young’s modulus was 17.4, 22.6 and 26.1 MPa for low, mid and high density corks respectively. This density effect was more evident in the plateau region of the progressive buckling of the cell walls (σ30 was respectively 1.07, 1.29 and 1.54 MPa for the three density classes). The recovery of dimensions after compression in each direction was also studied following compression to 50% strain. The recovery was on average 50% of the initial deformation on the first day, and almost total after 15 days. The recovery was higher for corks with low density and in non radial directions.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Brazinha, Carla</style></author><author><style face="normal" font="default" size="100%">Fonseca, Ana P.</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author><author><style face="normal" font="default" size="100%">Teodoro, Orlando M. N. D.</style></author><author><style face="normal" font="default" size="100%">Crespo, João G.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Gas transport through cork: Modelling gas permeation based on the morphology of a natural polymer material</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Membrane Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Gas permeation</style></keyword><keyword><style  face="normal" font="default" size="100%">Knudsen transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Natural polymers</style></keyword><keyword><style  face="normal" font="default" size="100%">solubility</style></keyword><keyword><style  face="normal" font="default" size="100%">Solution–diffusion model</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://linkinghub.elsevier.com/retrieve/pii/S0376738812007636</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">428</style></volume><pages><style face="normal" font="default" size="100%">52 - 62</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Natural polymers have been studied during the last years for the transport and separation of liquid and gas mixtures, in terms of solubility and permeability data, and their structure and mechanical properties have been characterised. However, no transport models have been reported, relating transport with the material morphology. Cork is a natural cellular material containing three structural polymers (suberin, lignin and polysaccharides). Cork is considered a natural polymer, with economic relevance due to its sealing, non-toxic, stable and low-density properties. Cork was characterised in this work in terms of its solubility and permeability data in relation to various gases with different molecular mass: He, O2, N2, CO2 and 1,1,1,2-tetraﬂuoroethane (R134a). A morphological analysis of the structure of the cork sample chosen in this work was also performed using SEM (scanning electron microscopy) and TEM (transmission electron microscope) image analysis, which took into account the variation of each relevant structural parameter. A transport model was developed supported on the morphology of cork characterised in this work. The transport model developed considers that gas permeation occurs through the plasmodesmata, which are channels with approximately 100 nm of diameter that cross the cell walls of the cork cells. It was found that gas transport follows a Knudsen mechanism, as proved by the gas permeability behaviour with increasing gas molecular mass, with a negligible contribution of viscous transport to the total ﬂux.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Fonseca, Ana Luisa</style></author><author><style face="normal" font="default" size="100%">Brazinha, Carla</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author><author><style face="normal" font="default" size="100%">Crespo, João G.</style></author><author><style face="normal" font="default" size="100%">Teodoro, Orlando M. N. D.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Permeability of Cork for Water and Ethanol</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Agricultural and Food Chemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">diffusion</style></keyword><keyword><style  face="normal" font="default" size="100%">permeability</style></keyword><keyword><style  face="normal" font="default" size="100%">sealing properties</style></keyword><keyword><style  face="normal" font="default" size="100%">Sorption</style></keyword><keyword><style  face="normal" font="default" size="100%">water transport</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1021/jf4015729</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">61</style></volume><pages><style face="normal" font="default" size="100%">9672 - 9679</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Transport properties of natural (noncompressed) cork were evaluated for water and ethanol in both vapor and liquid phases. The permeability for these permeants has been measured, as well as the sorption and diffusion coefficients. This paper focuses on the differences between the transport of gases? relevant vapors and their liquids (water and ethanol) through cork. A transport mechanism of vapors and liquids is proposed. Experimental evidence shows that both vapors and liquids permeate not only through the small channels across the cells (plasmodesmata), as in the permeation of gases, but also through the walls of cork cells by sorption and diffusion as in dense membranes. The present study also shows that cork permeability for gases was irreversibly and drastically decreased after cork samples were exposed to ethanol or water in liquid phase.</style></abstract><issue><style face="normal" font="default" size="100%">40</style></issue><notes><style face="normal" font="default" size="100%">doi: 10.1021/jf4015729doi: 10.1021/jf4015729The following values have no corresponding Zotero field:&lt;br/&gt;publisher: American Chemical Society</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Variability of the Chemical Composition of Cork</style></title><secondary-title><style face="normal" font="default" size="100%">BioResources</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2013</style></year></dates><volume><style face="normal" font="default" size="100%">8</style></volume><pages><style face="normal" font="default" size="100%">2246-2256</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The chemical composition of cork was determined, following a sampling that covered the whole production area in Portugal (29 provenances from six regions) with samples taken at cork stripping. To analyse between population variations, a more intensive sampling was made in two locations. The overall mean chemical composition of cork was: extractives 16.2% (dichloromethane 5.8%, ethanol 5.9%, water 4.5%), suberin 42.8% (long-chain lipids 41.0%, glycerol 3.8%), and lignin 22.0% (Klason 21.1%, acid soluble 0.9%). The suberin compositional ratio of long chain lipids to glycerol, LCLip:Gly, was 11.3. The proportion of neutral sugars in the polysaccharides was: glucose 46.1%, xylose 25.1%, arabinose 18.0%, mannose 3.0%, galactose 7.3%, and rhamnose 0.5%. The range of values was large and the variation between individual trees seemed to be the major factor of the differences. Geographical location of cork production was statistically significant only in a few cases when considering site and not when considering regions. The population variation in two sites was important and the absolute difference between the site mean values was small. This research covers the natural variability of cork’s chemical composition and discusses the contribution of the structural compounds to the variation of cork properties.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Cellular structure and chemical composition of cork from the Chinese cork oak (Quercus variabilis)</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Wood Science</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2012</style></year></dates><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Quercus variabilis Blume, the Chinese cork oak, is an oak species with a thick cork outer bark. The cork is exploited at a limited scale in China and considered of lower quality than the commercial cork from Quercus suber. We studied an industrial cork granulate feedstock of Q. variabilis in relation to cellular structure and chemical composition and compared it to Q. suber cork under a material’s perspective. The cork of Q.variabilis has 1.1 % ash, 9.6 % extractives, 34.8 % suberin and 19.1 % lignin. The monosaccharide composition with shows a predominance of hemicelluloses: glucose 42.8 % of total neutral sugars, xylose 27.5 %, arabinose 15.4 %, galactose 9.0 %, mannose 4.0 %, rhamnose 1.2 %. The FT-IR spectrum shows the indicative peaks of suberin. The composition is overall similar to that of Q. suber cork. Q. variabilis cork has the typical cellular characteristics of bark cork tissues with a regular and radially aligned structure of cells without intercellular voids. Solid volume fraction was estimated at approximately 16 %. Compared with Q. suber, the Q. variabilis cork cells are smaller, the cell wall undulation and the overall row alignment less homogeneous, the cell surface is irregular and the solid volume proportion higher. The characteristics of Q. variabilis cork support its use as a cellular material for sealing, insulation and energy absorption, but the overall quality is lower than that of Q. suber cork. The negative impact of the higher density and structural lower uniformity at tissue and cell level should be evaluated for processing and product performance.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Costa, Augusta</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Drying kinetics of cork planks in a cork pile in the field</style></title><secondary-title><style face="normal" font="default" size="100%">Food and Bioproducts Processing</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">empirical drying models</style></keyword><keyword><style  face="normal" font="default" size="100%">Moisture content</style></keyword><keyword><style  face="normal" font="default" size="100%">moisture ratio</style></keyword><keyword><style  face="normal" font="default" size="100%">natural sun drying</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2012///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://linkinghub.elsevier.com/retrieve/pii/S0960308512000624</style></url></web-urls></urls><pages><style face="normal" font="default" size="100%">1 - 9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Moisture content is one important parameter in the trading of raw cork planks after harvesting. This study presents a mathematical modeling of the drying curve of raw cork planks in a cork pile in the ﬁeld, under natural sun drying conditions. Experimental data were obtained by following the water loss (i.e. by daily weighing) of 97 cork planks positioned in nine points within a cork pile. Immediately after harvesting, the raw cork planks had a mean moisture content in a dry basis of 40.4% and after 20-day drying 16.6%. The drying process of the cork planks showed three phases: drying was very fast in the ﬁrst 2 days; in the next 2–15 days there was a decreasing drying rate; and a ﬁnal phase, after 15 days in the cork pile, with a slightly decreasing drying rate. Mathematical modeling provided a direct relation between moisture content and drying time. After comparing sixteen empirical drying models, the Modiﬁed Henderson and Pabis model showed the best ﬁt. According to this model, the cork planks are commercial dry (14% moisture content in a wet basis) 15 days after harvest.</style></abstract><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: Institution of Chemical Engineers</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Lignin monomeric composition of corks from the barks of Betula pendula, Quercus suber and Quercus cerris determined by Py–GC–MS/FID</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Analytical and Applied Pyrolysis</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2012</style></year></dates><publisher><style face="normal" font="default" size="100%">Elsevier B.V.</style></publisher><pages><style face="normal" font="default" size="100%">1-7</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Samples of cork tissues separated from the barks of Betula pendula, Quercus suber and Quercus cerris were characterized by Py–GC–MS/FID in respect to composition of lignin. The pyrolysis temperature influenced the yield of pyrolysis products, and in the conditions usually applied to wood pyrolysis (550 ◦C) suberin is only partially degraded into products. The lignin composition of the three corks showed predominantly a guaiacyl-based lignin: guaiacyl (G) units represented 85.7%, 96.4% and 93.7% of lignin respectively in B. pendula, Q. suber and Q. cerris corks, while syringyl (S) units amounted respectively to 11.9%, 2.5% and 2.7% and p-hydroxyphenyl (H) units to 2.4%, 1.1% and 3.6%. Pyrolysis of the woods of these same species confirmed the GS character of their lignins in contrast to the corks G-lignin type. The influence of ferulic acid in the results and its integration in a heterogeneous cork lignin structure was discussed.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Study of thermochemical treatments of cork in the 150–400°C range using colour analysis and FTIR spectroscopy</style></title><secondary-title><style face="normal" font="default" size="100%">Industrial Crops and Products</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2012</style></year></dates><volume><style face="normal" font="default" size="100%">38</style></volume><pages><style face="normal" font="default" size="100%">132-138</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A study of chemical transformations of cork during heat treatments was made using colour variation and FTIR analysis. The cork enriched fractions from Quercus cerris bark were subjected to isothermal heating in the temperature range 150–400 ◦ C and treatment time from 5 to 90min. Mass loss ranged from 3% (90min at 150 ◦ C) to 71% (60min at 350 ◦ C). FTIR showed that hemicelluloses were thermally degraded ﬁrst while suberin remained as the most heat resistant component. The change of CIE-Lab parameters was rapid for low intensity treatments where no signiﬁcant mass loss occurred (at 150 ◦ C L* decreased from the initial 51.5 to 37.3 after 20min). The decrease in all colour parameters continued with temperature until they remained substantially constant with over 40% mass loss. Modelling of the thermally induced mass loss could be made using colour analysis. This is applicable to monitoring the production of heat expanded insulation agglomerates.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Temperature-induced structural and chemical changes in cork from Quercus cerris</style></title><secondary-title><style face="normal" font="default" size="100%">Industrial Crops and Products</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2012</style></year></dates><volume><style face="normal" font="default" size="100%">37</style></volume><pages><style face="normal" font="default" size="100%">508-513</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The effects of temperature on anatomical and chemical characteristics of Quercus cerris cork were examined. Cork samples were subjected to isothermal air heating between 150 ◦ C and 400 ◦ C and analyzed for mass loss, cellular structure and chemical composition. The thermal decomposition of Q. cerris cork is similar to that of Q. suber cork. Cork is thermally stable below 200 ◦ C and after that degradation depended on temperature and heating time with increasing mass loss, i.e. 3% at 200 ◦ C 10min and 46% at 350 ◦ C 60min.With temperature and starting at 200 ◦ C, cells expanded, cell wall thickness was reduced and corrugations were lost. Extractives degraded at lower temperatures, although aliphatic extractives were found to be more stable. Suberin from Q. cerris was more heat resistant than Q. suber suberin, while lignin showed similar resistance. These results provide a basis for studies on the production of Q. cerris bark expanded cork agglomerates for insulation purposes.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">The cellular structure of cork from Quercus cerris var. cerris bark in a materials’ perspective</style></title><secondary-title><style face="normal" font="default" size="100%">Industrial Crops and Products</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><volume><style face="normal" font="default" size="100%">34</style></volume><pages><style face="normal" font="default" size="100%">929-936</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Cork in the outer bark of trees is among the valuable raw materials of biological origin due to properties that result mainly from its cellular structure. Large scale commercial utilization of cork has been only achieved with cork from Quercus suber. Another oak species, Quercus cerris, also contains substantial, albeit not continuous, regions of cork that are clearly visible to the naked eye but are so far considered as a waste material. Bark samples of Q. cerris var. cerris trees were collected from the Andırın province, Turkey. Cork portions were separated and their cellular structure was investigated with optical and electron scanning microscopy observations. The results were compared with Q. suber cork. Q. cerris cork has the typical features of cork tissues with a regular and radially aligned structure of suberized cells without intercellular voids, showing a ring structure and a distinction of earlycork and latecork cells. Solid volume fraction was estimated at 25% (22% in earlycork, 36% in latecork). In Q. cerris cork cells are smaller, cell wall thickness and solid volume fraction are higher, and the tissue is less homogeneous with a higher content of ligniﬁed inclusions than in Q. suber cork. These factors will negatively inﬂuence quality in regard to density and mechanical properties associated to elasticity. However, this does not impair its use for production of granulates and agglomerates, e.g. for insulation and energy absorption. Separation of the cork fraction from the bark is a step required before further processing and use.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Characterization of radial bending properties of cork</style></title><secondary-title><style face="normal" font="default" size="100%">European Journal of Wood and Wood Products</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><volume><style face="normal" font="default" size="100%">69</style></volume><pages><style face="normal" font="default" size="100%">557-563</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The behaviour of cork under three point bending stress in the radial direction was evaluated in relation to porosity (range 2.0–15.4%) and density (range 0.160– 0.220 g cm−3 ). The study was made using water-boiled cork planks of two commercial quality classes (good and poor quality) collected at an industrial mill. Cork samples were cut with the largest dimension in two directions, axial and tangential, and with the load zone in the inner part and the outer part of the plank. The stress-strain curves obtained in bending were similar for the different test specimens and similar to those observed for tensile tests in cork but the mechanical resistance of cork in bending was higher than in tension and lower than in compression. The direction of the internal stress in samples submitted to bending was a highly signiﬁcant factor of variation. The curves showed an initial linear elastic region with a mean Young’s modulus of 14 MPa for the tangential direction and 21 MPa for the axial direction, followed by a region of a gradual cork yielding up to a peak load, and failure at an average stress of 1.2 MPa and a strain of 14%. There was signiﬁcant difference in the bending properties of cork samples obtained from cork planks of different quality classes. Density and porosity were not individually well correlated with the mechanical parameters. It was however possible to model Young’s modulus by combining porosity and density.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Teixeira, Rita Teresa</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Suberized Cell Walls of Cork from Cork Oak Differ from Other Species</style></title><secondary-title><style face="normal" font="default" size="100%">Microscopy and Microanalysis</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">cell wall</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">lamellae</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">suberin</style></keyword><keyword><style  face="normal" font="default" size="100%">ultrastructure</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2010///</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">16</style></volume><pages><style face="normal" font="default" size="100%">569 - 575</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Plants have suberized cells that act as protective interfaces with the environment or between different plant tissues. A lamellar structure of alternating dark and light bands has been found upon transmission electron microscopy (TEM) observation of cork cells and considered a typical feature of the suberized secondary wall. We observed cork cells from periderms of Quercus suber, Quercus cerris, Solanum tuberosum, and Calotropis procera by TEM after uranyl acetate and lead citrate staining. A lamellated structure was observed in S. tuberosum and C. procera but not in Q. suber and Q. cerris where the suberized cell wall showed a predominantly hyaline aspect with only a dark dotted staining. Removal of suberin from Q. suber cells left a thinner secondary wall that lost the translucent aspect. We hypothesize that the species' specific chemical composition of suberin will result in different three-dimensional macromolecular development and in a different spatial location of lignin and other aromatics. A lamellated ultrastructure is therefore not a general feature of suberized cells.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Anjos, Ofélia</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author><author><style face="normal" font="default" size="100%">Rosa, M. Emília</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Tensile properties of cork in axial stress and influence of porosity, density, quality and radial position in the plank</style></title><secondary-title><style face="normal" font="default" size="100%">European Journal of Wood and Wood Products</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Density</style></keyword><keyword><style  face="normal" font="default" size="100%">Porosity (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">Quality</style></keyword><keyword><style  face="normal" font="default" size="100%">Stress</style></keyword><keyword><style  face="normal" font="default" size="100%">Tensile</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2010///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/10.1007/s00107-009-0407-0</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">69</style></volume><pages><style face="normal" font="default" size="100%">85 - 91</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The behaviour of cork under tensile stress in the axial direction was studied for samples taken from cork planks of good (class 1) and poor (class 4) quality grades and at three radial positions within the plank (inner, mid and outer positions). The effect of cork density (ranging from 0.123 to 0.203 g cm−3 ) and porosity (ranging from 2.8 to 9.6% in the tangential surface) on Young’s modulus and fracture stress and strain was studied. The tensile stress-strain curves of cork showed an elastic deformation up to 2% strain with a Young’s modulus of 30.8 MPa, and a fracture stress of 1.05 MPa at a strain of 7.1% for class 1, and Young’s modulus of 26.1 MPa, and a fracture stress of 0.77 MPa at a strain of 5.5% for class 4. Fracture always started at a pore. The quality class and the radial position in the plank were highly signiﬁcant factors of the tensile properties variation with good quality cork in the inner part of the plank showing the highest strength. Density inﬂuenced the elastic behaviour of cork with a highly signiﬁcant correlation of increasing E with density,but not so clearly the fracture stress and strain. The variability of tensile properties with porosity was large and although signiﬁcant, the correlations were lower in spite of a decreasing trend of E with porosity. Fracture depended on the type of defects in cork.</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Ultrastructural Observations Reveal the Presence of Channels between Cork Cells</style></title><secondary-title><style face="normal" font="default" size="100%">MICROSCOPY AND MICROANALYSIS</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><publisher><style face="normal" font="default" size="100%">CAMBRIDGE UNIV PRESS</style></publisher><pub-location><style face="normal" font="default" size="100%">32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA</style></pub-location><volume><style face="normal" font="default" size="100%">15</style></volume><pages><style face="normal" font="default" size="100%">539-544</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The ultrastructure of phellem cells of Quercus Silber L. (cork oak) and Calotropis procera (Ait) R. Br. were analyzed using electron transmission microscopy to determine the presence or absence of plasmodesmata (PD). Different types of Q. Silber cork samples were studied: one year shoots; virgin cork (first periderm), reproduction cork (traumatic periderm), and wet cork. The channel structures of PD were found in all the samples crossing adjacent cell walls through the suberin layer of the secondary wait. Calotropis phellem also showed PD crossing the cell walls of adjacent cells but in fewer numbers compared to Q. suber. In one year stems of cork oak, it was possible to follow the physiologically active PD with ribosomic accumulation next to the aperture of the channel seen in the phellogen cells to the completely obstructed channels in the dead cells that characterize the phellem tissue.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Teixeira, Rita Teresa</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Ultrastructural Observations Reveal the Presence of Channels between Cork Cells</style></title><secondary-title><style face="normal" font="default" size="100%">MICROSCOPY AND MICROANALYSIS</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Calotropis procera</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">phellogen</style></keyword><keyword><style  face="normal" font="default" size="100%">plasmodesmata</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">suberin</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2009///</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">15</style></volume><pages><style face="normal" font="default" size="100%">539 - 544</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The ultrastructure of phellem cells of Quercus Silber L. (cork oak) and Calotropis procera (Ait) R. Br. were analyzed using electron transmission microscopy to determine the presence or absence of plasmodesmata (PD). Different types of Q. Silber cork samples were studied: one year shoots; virgin cork (first periderm), reproduction cork (traumatic periderm), and wet cork. The channel structures of PD were found in all the samples crossing adjacent cell walls through the suberin layer of the secondary wait. Calotropis phellem also showed PD crossing the cell walls of adjacent cells but in fewer numbers compared to Q. suber. In one year stems of cork oak, it was possible to follow the physiologically active PD with ribosomic accumulation next to the aperture of the channel seen in the phellogen cells to the completely obstructed channels in the dead cells that characterize the phellem tissue.</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;pub-location: 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA&lt;br/&gt;publisher: CAMBRIDGE UNIV PRESS</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Effect of quality, porosity and density on the compression properties of cork</style></title><secondary-title><style face="normal" font="default" size="100%">Holz als Roh- und Werkstoff</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><volume><style face="normal" font="default" size="100%">66</style></volume><pages><style face="normal" font="default" size="100%">295-301</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The compression properties of cork were studied on samples obtained from cork planks of two commercial quality classes (good and poor quality), with densities ranging from 0.12–0.20g cm−3 and porosities from 0.5 to 22.0%. The stress-strain curves were characterized by an elastic region up to approximately 5% strain, followed by a large plateau up to 60% strain caused by the progressive buckling of cell walls, and a steep stress increase for higher strains corresponding to cell collapse. The direction of compression was a highly signiﬁcant factor of variation, with cork showing higher strength for the radial compression. Density inﬂuenced compression and cork samples with higher density showed overall larger resistance to compression in the three directions. In the elastic region, an exponential model of Young’s modulus in function of cork density could be adjusted. The effect of porosity on compression was small and the stress-strain curves were similar regardless of the porosity of the samples, although there was a trend toward an overall increase of stress with porosity for higher strains. Porosity was characterised by a high variability in the anatomical features of the lenticular ﬁlling material and the presence of collapsed and thick walled ligniﬁed cells. The inclusion of a porosity parameter for the modelling of the elastic modulus did not improve the prediction obtained with densitybased models. There was no signiﬁcant difference in the compression properties of cork samples obtained from cork planks of good and poor quality classes.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Anjos, Ofélia</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author><author><style face="normal" font="default" size="100%">Rosa, M. Emília</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Effect of quality, porosity and density on the compression properties of cork</style></title><secondary-title><style face="normal" font="default" size="100%">Holz als Roh- und Werkstoff</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Compression</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Density</style></keyword><keyword><style  face="normal" font="default" size="100%">Porosity</style></keyword><keyword><style  face="normal" font="default" size="100%">Quality</style></keyword><keyword><style  face="normal" font="default" size="100%">stress (voyant)</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2008///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/10.1007/s00107-008-0248-2</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">66</style></volume><pages><style face="normal" font="default" size="100%">295 - 301</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The compression properties of cork were studied on samples obtained from cork planks of two commercial quality classes (good and poor quality), with densities ranging from 0.12–0.20g cm−3 and porosities from 0.5 to 22.0%. The stress-strain curves were characterized by an elastic region up to approximately 5% strain, followed by a large plateau up to 60% strain caused by the progressive buckling of cell walls, and a steep stress increase for higher strains corresponding to cell collapse. The direction of compression was a highly signiﬁcant factor of variation, with cork showing higher strength for the radial compression. Density inﬂuenced compression and cork samples with higher density showed overall larger resistance to compression in the three directions. In the elastic region, an exponential model of Young’s modulus in function of cork density could be adjusted. The effect of porosity on compression was small and the stress-strain curves were similar regardless of the porosity of the samples, although there was a trend toward an overall increase of stress with porosity for higher strains. Porosity was characterised by a high variability in the anatomical features of the lenticular ﬁlling material and the presence of collapsed and thick walled ligniﬁed cells. The inclusion of a porosity parameter for the modelling of the elastic modulus did not improve the prediction obtained with densitybased models. There was no signiﬁcant difference in the compression properties of cork samples obtained from cork planks of good and poor quality classes.</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">The periderm development in Quercus suber</style></title><secondary-title><style face="normal" font="default" size="100%">IAWA Journal</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2004</style></year></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">325-335</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In the cork oak (Quercus suber L.), the phellogen differentiates during the first year of growth in the cell layer immediately under the epidermis and divides to form 3–6 suberized phellem cells. Division of the phellogen only occurs after suberization of the previous divided cell. During the first four years of growth, the phellem cells have tannin-filled lumens and it is only in the 5th to 7th years that they acquire the characteristics of ʻadultʼ cork cells with empty lumens and thin suberized walls. The len- ticels are formed by the lenticular phellogen, which differentiates under the stomata and has a high meristematic activity. In this region, the cells are unsuberized, with a loose arrangement and intercellular voids, consti- tuting the filling or complementary tissue. After three years, the lenticels appear as small protuberances that soon become conspicuous. Inclusions of sclerenchymatous nodules and isolated sclereids occur occasionally mostly in the vicinity of, or in, the lenticels.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Caractérisation de la croissance et de la qualité du liège dans une région de production</style></title><secondary-title><style face="normal" font="default" size="100%">Ann. For. Sci.</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2000</style></year></dates><volume><style face="normal" font="default" size="100%">57</style></volume><pages><style face="normal" font="default" size="100%">187-193</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Cork growth and quality were characterised in 5 cork oak stands within the production area of the Sado basin (Alcácer do Sal, Portugal) based on a field sampling on 40 trees/stand. Cork thickness was on average 33.8 mm, with 75% of the samples in the commercial classes above 27 mm suitable for production of stoppers. Porosity measured by image analysis was 4.6% on average. Between tree and between stand variability of cork quality was large. The annual average cork growth for a production cycle with 8 complete growth years was 4.1 mm, being highest during the years following cork extraction and decreasing during the cycle. For this region, a production cycle of 9 years is adequate for raw-material industrial requirements. The results show the importance of between tree variability in growth and especially in quality.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Ferreira, Alexandra</style></author><author><style face="normal" font="default" size="100%">Lopes, Fernando</style></author><author><style face="normal" font="default" size="100%">Pereira, Helena</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Caractérisation de la croissance et de la qualité du liège dans une région de production</style></title><secondary-title><style face="normal" font="default" size="100%">Ann. For. Sci.</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Growth</style></keyword><keyword><style  face="normal" font="default" size="100%">Porosity</style></keyword><keyword><style  face="normal" font="default" size="100%">Quality</style></keyword><keyword><style  face="normal" font="default" size="100%">variability</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1051/forest:2000169</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">57</style></volume><pages><style face="normal" font="default" size="100%">187 - 193</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Cork growth and quality were characterised in 5 cork oak stands within the production area of the Sado basin (Alcácer do Sal, Portugal) based on a field sampling on 40 trees/stand. Cork thickness was on average 33.8 mm, with 75% of the samples in the commercial classes above 27 mm suitable for production of stoppers. Porosity measured by image analysis was 4.6% on average. Between tree and between stand variability of cork quality was large. The annual average cork growth for a production cycle with 8 complete growth years was 4.1 mm, being highest during the years following cork extraction and decreasing during the cycle. For this region, a production cycle of 9 years is adequate for raw-material industrial requirements. The results show the importance of between tree variability in growth and especially in quality.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Methanolysis of bark suberins: analysis of glycerol and acid monomers</style></title><secondary-title><style face="normal" font="default" size="100%">Phytochemical Analysis</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2000</style></year></dates><volume><style face="normal" font="default" size="100%">11</style></volume><pages><style face="normal" font="default" size="100%">45-51</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The depolymerization and subsequent analysis of cork suberins from the outer barks of Pseudotsuga menziesii and Quercus suber was performed using a simpliﬁed methanolysis procedure. The amount of sodium methoxide catalyst was maintained at 20–30 mM and the methanolysis mixture was submitted to trimethylsilyl derivatisation and used directly for gas chromatographic analysis, allowing simultaneous quantiﬁcation of glycerol and long-chain monomers. Response factors for glycerol, ferulic acid and one saturated homologue representing each of the suberinic families (i.e. the 1-alkanols, 1-alkanoic acids, vhydroxyacids and a,v-diacids) were determined. Effective depolymerization of suberin was checked using the infrared specta of the residues after methanolysis. Glycerol is a major constituent of the suberins from P. menziesii (26% of total) and from Q. suber (14%). In both suberins, a,v-diacids are dominant, i.e. 54% of the long-chain monomers in P. menziesii (mostly saturated C16-C22 homologues and the C18 unsaturated diacid), and 53% in Q. suber (mostly the C18 unsaturated diacid and mid-chain oxygenated (epoxide and vic-diol) derivatives). In P. menziesii epoxyacids are absent. The importance of glycerol and a,v-diacids as suberin monomers supports a polymeric structure based on their successive esteriﬁcation.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Feruloyl Esters of ω-Hydroxyacids in Cork Suberin</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Wood Chemistry and Technology</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1998</style></year></dates><publisher><style face="normal" font="default" size="100%">Taylor &amp; Francis</style></publisher><volume><style face="normal" font="default" size="100%">18</style></volume><pages><style face="normal" font="default" size="100%">207-217</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Feruloyl esters of ?-hydroxyacids were found in the alcoholysis products of suberin from Quercus suber cork. Their identification was made from mass spectra and by comparison with synthetic model compounds. The co-hydroxyls of suberinic hydroxyacids are thought to be the ester-bonding points between suberin aliphatics and associated aromatics.</style></abstract><notes><style face="normal" font="default" size="100%">doi: 10.1080/02773819809349577</style></notes><research-notes><style face="normal" font="default" size="100%">doi: 10.1080/02773819809349577</style></research-notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Cork Suberin: A Glyceryl Based Polyester</style></title><secondary-title><style face="normal" font="default" size="100%">Holzforschung - International Journal of the Biology, Chemistry, Physics and Technology of Wood</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1997</style></year></dates><volume><style face="normal" font="default" size="100%">51</style></volume><pages><style face="normal" font="default" size="100%">225-234</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Total depolymerization of cork from the cork oak (Quercus suber L.) by using a sodium methoxide catalysed methanolysis solubilized 53.2 % of the material, including 5.2 % of glycerol, 48,0 % of suberinic fatty acids and alcohols and minor amounts of ferulic acid. A very mild depolymerization using calcium oxide treated methanol, which solubilized only 2.0% of the cork material was studied by GC-MS. In the solubilized material, the total amount of aliphatic acids was 43.8 % (including alkanoic acids 4.0%. ω-hydroxyacids 13.2% and α,ω-diacids 26.6%), of 1-alkanols 2.1 % and of monoacylglycenols 32.1%. It was possible to identify 1-monoacylglycerols and 2-monoacylglycerols of alkanoic acids (1,2%), ω-hydroxyacids (3.7 %) and α,ω-diacids (22.8 %). It is proposed that suberin is a glyceryl based polymer and that its insoluble character is given, at least in part, by the cross-linking of dicarboxylic fatty acids with glycerol. The term suberin should be used for this aliphatic polyester component of the cell wall.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>3</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Suberina: o polímero responsá vel pelas propriedades da cortiça</style></title><secondary-title><style face="normal" font="default" size="100%">II Congreso Forestal Español</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1997</style></year></dates><pub-location><style face="normal" font="default" size="100%">Pamplona</style></pub-location><pages><style face="normal" font="default" size="100%">225-228</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The macromolecular structure of suberin, the biopolymer mainly responsable for cork properties, is dicussed. The link of the suberinic aliphatic acids to glycerol is presented, supporting the hypothesis that suberin is a glyceridic polyester. The linkage of this aliphatic part, through ferulic acid, to the aromatic part, and the similarities of the later to lignin, are discussed. K.W.:</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>47</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Variaçáo da porosidade da cortiça ao longo do tronco dosobreiro</style></title><secondary-title><style face="normal" font="default" size="100%">II Congreso Forestal Español</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1997</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1997///</style></date></pub-dates></dates><pages><style face="normal" font="default" size="100%">253 - 258</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The within tree variation of cork quality has practical relevance when considering the methodology for estimating the quality of production using a field sampling. Samples are usually taken at breast height and an indication how quality at this level might relate to the overall average quality would help to improve estimates for the overall stand cork quality. The porosity of cork was analysed for whole stems. A total of 12 trees were evaluated, from six sites (Mora, Palma, Porto Alto, Grandola, Azaruja and Chamusca). The porosity was measured using image analysis techniques in tangential sections and in transverse sections. The cork for the different trees observed had different average porosities, ranging from 2.7% to 14.5% in the transverse section at b.h .. Within tree variatíon of cork porosity was found, with a average pattern of decreasing porosity within tree height. However a umque pattern of variation could not be established.</style></abstract><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;periodical: II Congreso Forestal Español&lt;br/&gt;pub-location: Pamplona</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>3</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Variaçáo da porosidade da cortiça ao longo do tronco dosobreiro</style></title><secondary-title><style face="normal" font="default" size="100%">II Congreso Forestal Español</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1997</style></year></dates><pub-location><style face="normal" font="default" size="100%">Pamplona</style></pub-location><pages><style face="normal" font="default" size="100%">253-258</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The within tree variation of cork quality has practical relevance when considering the methodology for estimating the quality of production using a field sampling. Samples are usually taken at breast height and an indication how quality at this level might relate to the overall average quality would help to improve estimates for the overall stand cork quality. The porosity of cork was analysed for whole stems. A total of 12 trees were evaluated, from six sites (Mora, Palma, Porto Alto, Grandola, Azaruja and Chamusca). The porosity was measured using image analysis techniques in tangential sections and in transverse sections. The cork for the different trees observed had different average porosities, ranging from 2.7% to 14.5% in the transverse section at b.h .. Within tree variatíon of cork porosity was found, with a average pattern of decreasing porosity within tree height. However a umque pattern of variation could not be established.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>7</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">High - pressure extraction of cork with CO2 and 1,4-dioxane</style></title><secondary-title><style face="normal" font="default" size="100%">High Pressure Chemical Engineering Proceedings of the 3rd International Symposium on High Pressure Chemical Engineering</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1996</style></year></dates><publisher><style face="normal" font="default" size="100%">Elsevier</style></publisher><volume><style face="normal" font="default" size="100%">Volume 12</style></volume><pages><style face="normal" font="default" size="100%">417-422</style></pages><isbn><style face="normal" font="default" size="100%">0921-8610</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The extraction of cork from cork-oak (Quercus suber L.) by high-pressure dioxane and supercritical CO2 mixtures was studied at 170 bar and in the temperature range of 160°C - 180°C. Suberin is preferably extracted, but extraction percentages were lower than 46%. Lignin extraction percentages are lower than 11%. Extraction selectivity did not change significantly with extracting fluid composition. The results so far obtained support the idea of the existence of an extensive polymeric system across the cell wall and the concept of a close interaction of suberin and lignin, which hinders lignin depolymerization and solubilization in the high-pressure fluid. Fourier transform infrared spectra of cork, extraction residues and extracts are also presented.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">THE CELLULAR STRUCTURE OF CORK FROM QUERCUS SUBER L</style></title><secondary-title><style face="normal" font="default" size="100%">IAWA Bulletin</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1987</style></year></dates><volume><style face="normal" font="default" size="100%">8</style></volume><pages><style face="normal" font="default" size="100%">213-218</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The main characteristics of the cellular struc- ture of cork from Quercus suber L. are review- ed and comph;mented with new observations of virgin and reproduction cork by scanning electron microscopy. Particular emphasis is given to cell geometry and topology and to the corrugations that are observed in the cell walls. The effect of the growth season in these fea- tures is described. Large variations in cell size, wall thickness ajld corrugations are reported. Key words: Quercus SIlber, cork, cell gcometry, topology, cell wall corrugations.</style></abstract></record></records></xml>