Littérature scientifique sur le sujet « Quercus cerri »
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Articles de revues sur le sujet "Quercus cerri"
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La Marca, O., et G. Notarangelo. « Influence of thinnings on wood production in a Turkey oak (Quercus cerrisL.) in southern Italy ». Forest@ - Rivista di Selvicoltura ed Ecologia Forestale 6, no 1 (19 mai 2009) : 173–85. http://dx.doi.org/10.3832/efor0581-006.
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Yang, Jia, Yu-Fan Guo, Xiao-Dan Chen, Xiao Zhang, Miao-Miao Ju, Guo-Qing Bai, Zhan-Lin Liu et Gui-Fang Zhao. « Framework Phylogeny, Evolution and Complex Diversification of Chinese Oaks ». Plants 9, no 8 (13 août 2020) : 1024. http://dx.doi.org/10.3390/plants9081024.
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Oaks (Quercus L.) are ideal models to assess patterns of plant diversity. We integrated the sequence data of five chloroplast and two nuclear loci from 50 Chinese oaks to explore the phylogenetic framework, evolution and diversification patterns of the Chinese oak’s lineage. The framework phylogeny strongly supports two subgenera Quercus and Cerris comprising four infrageneric sections Quercus, Cerris, Ilex and Cyclobalanopsis for the Chinese oaks. An evolutionary analysis suggests that the two subgenera probably split during the mid-Eocene, followed by intergroup divergence within the subgenus Cerris around the late Eocene. The initial diversification of sections in the subgenus Cerris was dated between the mid-Oligocene and the Oligocene–Miocene boundary, while a rapid species radiation in section Quercus started in the late Miocene. Diversification simulations indicate a potential evolutionary shift on section Quercus, while several phenotypic shifts likely occur among all sections. We found significant negative correlations between rates of the lineage diversification and phenotypic turnover, suggesting a complex interaction between the species evolution and morphological divergence in Chinese oaks. Our infrageneric phylogeny of Chinese oaks accords with the recently proposed classification of the genus Quercus. The results point to tectonic activity and climatic change during the Tertiary as possible drivers of evolution and diversification in the Chinese oak’s lineage.
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RODRÍGUEZ, WILLIAM DAVID, JOSÉ LUIS NAVARRETE-HEREDIA et JAN KLIMASZEWSKI. « Rove beetles collected with carrion traps (Coleoptera : Staphylinidae) in Quercus forest of Cerro de García, Jalisco and Quercus, Quercus-pine, and pine forests in other jurisdictions of Mexico ». Zootaxa 4433, no 3 (13 juin 2018) : 457. http://dx.doi.org/10.11646/zootaxa.4433.3.4.
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We present the species diversity of rove beetles (Coleoptera: Staphylinidae) collected with carrion baited traps in Quercus forests of Cerro de García, Jalisco, and provide a compilation of published species records in Quercus, Quercus-pine and pine forests in other jurisdictions of Mexico. This work includes taxonomic notes, information on species phenology, distribution, and their occurrence in Cerro de García (if applicable), and other jurisdictions of Mexico. In Cerro de García, 75 species were collected in total, of which 16 are shared with other Quercus forests in different locations, and 9 species are provided with new habitat data. The remaining individuals were only determined to morphospecies. In Mexico, there are 77 known species of rove beetles collected with carrion traps (determined to species or near species) and recorded from Quercus, Quercus-pine and pine forests. These species belong to 30 genera, 11 tribes and 10 subfamilies. This study provides biological information on Mexican rove beetles captured with carrion traps and highlights the importance of rove beetles as indicator species of habitat change for conservation analysis, forestry, agronomy and forensic sciences studies.
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MELIKA, GEORGE, JULI PUJADE-VILLAR, YOSHIHISA ABE, CHANG-TI TANG, JAMES NICHOLLS, NAKATADA WACHI, TATSUYA IDE et al. « Palaearctic oak gallwasps galling oaks (Quercus) in the section Cerris : re-appraisal of generic limits, with descriptions of new genera and species (Hymenoptera : Cynipidae : Cynipini) ». Zootaxa 2470, no 1 (14 mai 2010) : 1. http://dx.doi.org/10.11646/zootaxa.2470.1.1.
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We discuss the taxonomy of oak gallwasps (Hymenoptera: Cynipidae: Cynipini) whose lifecycle involves only Palaearctic oaks (Quercus subgen. Quercus) in the section Cerris. Recent phylogenetic reconstructions support a deep split between such Cerris-associated species in the genera Aphelonyx, Dryocosmus, Plagiotrochus, Neuroterus, Pseudoneuroterus and species and genera associated with oaks in the section Quercus sensu stricto. We reappraise the generic limits of the Cerris-associated genera, proposing new limits for Dryocosmus, Pseudoneuroterus and Neuroterus, establishing a new genus Cerroneuroterus, elevating Latuspina to a genus level, reestablishing the genera Chilaspis and Trichagalma and proposed new species name combinations. We provide a new key to oak gallwasp genera of the Palaearctic and keys to all species of genera associated with Cerris section oaks. We describe five new species, Aphelonyx kordestanica, Trichagalma formosana, Dryocosmus jungalii, Pseudoneuroterus mazandarani, and P. nichollsi.
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Petrovic, S., S. Sobajic, S. Rakic, A. Tomic et J. Kukic. « Investigation of kernel oils of Quercus robur and Quercus cerris ». Chemistry of Natural Compounds 40, no 5 (septembre 2004) : 420–22. http://dx.doi.org/10.1007/s10600-005-0003-4.
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Jan, Kabíček. « Phytoseiid mites on Quercus cerris in an urban park – short communication ». Plant Protection Science 53, No. 3 (28 mai 2017) : 181–86. http://dx.doi.org/10.17221/167/2016-pps.
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The community of phytoseiid mites on the leaves of non-indigenous Quercus cerris was studied in an intensively managed urban park during the years 2012–2014. Five phytoseiid species, namely Kampimodromus aberrans, Typhloseiulus peculiaris, Euseius finlandicus, Typhlodromus (Typhlodromus) pyri, and Paraseiulus triporus, were found on the studied oak leaves; three of them are generalist predators. K. aberrans and T. peculiaris were the dominant species (88.5% of all sampled phytoseiids), of which K. aberrans was the significantly most abundant species on the inspected oak leaves. Non-native Q. cerris can serve as a favourable host plant and refuge for certain phytoseiid species in environmentally unfriendly urban areas.
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Pinto, Diana, Santiago Diaz Franco, Ana Margarida Silva, Snezana Cupara, Marijana Koskovac, Ksenija Kojicic, Sónia Soares et al. « Chemical characterization and bioactive properties of a coffee-like beverage prepared from Quercus cerris kernels ». Food & ; Function 10, no 4 (2019) : 2050–60. http://dx.doi.org/10.1039/c8fo02536c.
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Najib, Rola, Tarek Houri, Yara Khairallah et Mahmoud Khalil. « Quercus cerris L. : An Overview ». Forestry Studies 74, no 1 (1 décembre 2021) : 1–9. http://dx.doi.org/10.2478/fsmu-2021-0001.
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Abstract The Turkey oak is a frequent tree species in the Mediterranean climate zones of southern Europe and Asia Minor. It has been used in the human diet, for medicinal purposes, firewood and charcoal production. Like all oaks, Turkey oak is suffering from dieback and decline owing to the combination of several detrimental factors, such as insects, diseases and unfavorable environment, leading to their deterioration and sometimes resulting in their early death.
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Bariska, Mihály, Zoltán Pásztory et Zoltán Börcsök. « On tylosis ultrastructure in Quercus cerris L. » Holzforschung 73, no 12 (26 novembre 2019) : 1121–23. http://dx.doi.org/10.1515/hf-2019-0028.
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Abstract A study of tylosis in European Turkey oak (Quercus cerris L.) shows correspondences in the formation of tyloses and of regular cell walls. The outer tylosis wall has a smooth, granular surface with simple perforations analogous to that of the primary wall of ordinary cells. The underlying wall stratum shows parallel oriented macro-fibrils, normally found in the secondary walls of regular cells. At the contact areas of tyloses, stabilizing seams can be observed. Various types of wall openings such as simple pits, blind pits and vestured pits were present. Also tylosis division was detected. The characteristics of parenchyma cell walls can be re-discovered in tyloses.
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Milanovic, Slobodan. « Development of gypsy moth (Lymantria dispar L) on the foliage of Quercus cerris L., Q. Petraea (matt) Liebl. and Q. Robur L. in the controlled conditions ». Bulletin of the Faculty of Forestry, no 96 (2007) : 55–67. http://dx.doi.org/10.2298/gsf0796055m.
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The development of Gypsy moth (Lymantria dispar L) was monitored in laboratory conditions, on the foliage of the species Quercus cerris L. Quercus petraea (Matt) Liebl. and Quercus robur L. The experiment was established in the controlled environmental conditions, at the temperature of 25?C, photoperiod 14:10 (day: night) and relative humidity 70%. The objective of the research was to determine the suitability of the study host plant species for gypsy moth development. The study results show that Gypsy moth caterpillars cultivated on Q. petraea foliage had a lower survival, higher number of moultings, longer preadult development and lower fecundity, which makes this species less suitable compared to the other two. Gypsy moth caterpillars cultivated on Q. cerris foliage had the highest survival degree the lowest number of moultings, the shortest preadult development and the highest fecundity, which makes this species the most favourable for gypsy moth development. Q. robur was between the former two species in this respect.
Thèses sur le sujet "Quercus cerri"
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Bajraktari, Agron. « Wood quality of Quercus cerris from Kosovo ». Doctoral thesis, ISA, 2018. http://hdl.handle.net/10400.5/15830.
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Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia - ULKosovo’s forest products industry is a very important part of Kosovo’s economy and within the present work data was collected through a survey of all sawmills in Kosovo and information gathering from the Ministry of Agriculture, Forestry and Rural Development of Kosovo. The forest resources and sawmill structure of Kosovo were analyzed and the availability of different species of wood in different regions of the country established. In parallel, the study of one home grown wood species, Quercus cerris, was conducted in order to improve its use in sawmilling to produce value added wood components. For this purpose, ten Quercus cerris trees, grown in two sites in Kosovo, were felled and discs taken at different stem height levels. Relevant data for this species was obtained on stem quality, including heartwood, sapwood and bark development as well as ring analysis. Chemical and durability characterization was also conducted together with the evaluation of density and Brinell hardness. Quercus cerris from Kosovo showed good potential as a timber species for the supply of stem wood to the saw-milling industry allowing good yields of heartwood-only sawn wood components. Taking into account the good technological properties measured together with the apparent low level of extracts and the low durability class against subterranean termites, interior or protected uses are highly recommended. The bark should also be considered for complementary valorization. Furthermore, based on the worked developed, a curricular programme combining scientific and technological knowledge for industrial management, communication knowledge and creative work was developed in close cooperation with wood processing enterprises in Kosovo, and with the Kosovo Wood Processing Association. Recommendations were also provided for further development of the forest and sawmill industry
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Dias, Ana Rita Pimenta. « Caracterização da qualidade da madeira de Quercus cerris para utilização exterior ». Master's thesis, ISA, 2017. http://hdl.handle.net/10400.5/14851.
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Mestrado em Engenharia Florestal e dos Recursos Naturais - Engenharia dos Produtos Florestais / Instituto Superior de AgronomiaEste trabalho teve como objetivo caracterizar a madeira de Quercus cerris e para tal realizaram-se os seguintes estudos: quantificação do cerne, borne e casca, caracterização da composição química da madeira de cerne e durabilidade natural do cerne. Os estudos incidiram em amostras de madeira de árvores de Q. cerris abatidas em duas regiões do Kosovo com classes de idade de 70 a 80 anos. Todas as árvores de Q. cerris apresentaram formação de cerne, com um contorno regular e cor castanha avermelhada distinta do borne de cor castanha mais clara. A área de cerne diminuiu da base para o topo e ao nível do DAP foi em média 57,2% e 43,2% nos dois locais. A espessura de borne variou entre 3,2-4,2 cm e 3,6- 4,6 cm para as árvores dos dois locais. O cerne do Q. cerris apresentou uma correlação positiva com o diâmetro do tronco enquanto a largura de borne foi independente do diâmetro das árvores. O teor médio de casca foi de 14,2% e 16,3 % em % da área total com casca. A composição química média da madeira de cerne Q. cerris foi: cinzas 0,93%, extrativos totais 6,7% e lenhina total 26,4%. Quanto aos polissacáridos eles são constituídos principalmente por glucose e xilose (respetivamente em média 60,7% e 32,2% dos monómeros). Os ensaios de durabilidade natural face ao ataque de térmitas subterrâneas, permitiram classificar a madeira de cerne de Q. cerris como não durável. Face a estes resultados, conclui-se que para a utilização da madeira de cerne de Q. cerris deve considerar-se a sua baixa resistência biológica
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Mirjana, Topić. « Fiziološki aspekti otpornosti hrasta lužnjaka (Quercus robur L.), cera (Quercus cerris L.) i crne topole (Populus nigra L.) u uslovima vodnog deficita ». Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2015. https://www.cris.uns.ac.rs/record.jsf?recordId=95391&source=NDLTD&language=en.
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U radu je ispitan uticaj vodnog deficita na fiziološke osobine klonova crne topole ipopulacija hrasta lužnjaka i cera, kao i mogućnost oporavka ovih biljaka nakon ponovnog uspostavljanja optimalnog vodnog režima. Cilj istraživanja je bio da se ukaže na potencijal ispitivanih genotipova topole i hrastova za opstanak u promenljivim uslovima životne sredine, u skladu sa aktuelnim klimatskim promenama koje uključuju smanjenje količine padavina i ograničenu dostupnost vode. Dobijeni rezultati su pokazali specifično variranje ispitivanih morfo-anatomskih, fizioloških i biohemijskih parametara koje je zavisilo od momentalne vlažnosti zemljišta na primenjenom tretmanu (kontrola, suša praćena oporavkom, konstantna suša) i od genotipa biljke. Negativan uticaj vodnog deficita na tretmanu konstantne suše je u najmanjoj meri bio ispoljen na rastenje klona topole X/32, populaciju hrasta lužnjaka L1 i populaciju hrasta cera C1. Indeks tolerancije na stres izračunat na osnovu visine biljke (PHSI) takodje je potvrdio dobru morfološku prilagodjenost pomenutih genotipovana uslove suše. Dobijene vrednosti indeksa stoma ukazuju da vodni status ispitivanih populacija hrastova nije bio naroĉito pogodjen vodnim deficitom na sušnim tretmanima. Tretman konstantne suše je u oba ogleda doveo do najvećeg smanjenja vrednostiparametara razmene gasova kod skoro svih genotipova. S druge strane, primenjeni sušni tretmani nisu uslovili smanjenje sadržaja fotosintetiĉkih pigmenata, kao ni parametra Fv/Fm, kod većine ispitivanih biljaka. U odnosu na kontrolu, sadržaj prolina u listovima ispitivanih biljaka na tretmanu konstantne suše bio je znaĉajno povećan, a aktivnost enzima nitrat-reduktaze značajno smanjena, kod većine genotipova. Genotipovi kod kojih u uslovima jakog vodnog deficita nije došlo do značajne promene većine ispitivanih morfo-anatomskih, fizioloških i biohemijskih parametara mogu biti od velike važnosti kad je u pitanju njihov odabir i upotreba za uspešno pošumljavanje sušnih staništa, kojih će biti sve više usled negativnog uticaja brojnih ekoloških činilaca nastalih kao posledica klimatskih promena.The impact of water deficit and recovery on physiological features of the black poplar clones, as well as of the oaks populations were analyzed. The aim of this research was to indicate the potential of the studied genotypes for survival under changing environmental conditions, in accordance with current climate changes, which include the reduction in amount of rainfall and limited water availability. Obtained results have shown a specific variation of studied morpho-anatomical, physiological and biochemical parameters which depended on soil humidity on the applied treatment (control, drought followed by recovery and permanent drought), as well as on plant genotype.Water deficit on permanent drought treatment had little negative effect on plant growth of poplar clone X/32, as well as oak populations L1 and C1. Plant height stress tolerance index also confirmed good morphological adaptation to drought of these genotypes. Stomatal index was not negatively affected by water deficit in oak plants. In both experiments, a permanent drought treatment led to the largest reduction in the values of gas exchange parameters in almost all genotypes.On the other hand, concentration of photosynthetic pigments was not considerably decreased in plants exposed to water deficit, as well as the parameter Fv/Fm, in most examined plants. Compared to the control, the impact of permanent drought treatment on biochemical parameters was expected, in the most cases. Compared to the control, proline content in leaves of most examined genotypes was significantly increased on permanent drought treatment, while nitrate reductase activity was significantly decreased.Examined genotypes exhibiting slight or no reduction in values of the most examined parameters during severe drought stress, could be used for afforestation in arid sites. Arid habitats appeared to be more numerous due to the effects of global climate changes.
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Nunes, Telma Filipa Chaves Pinto. « Caracterização da madeira de Quercus cerris. Análise anatómica, análise dendrocronológica e ensaios de dureza ». Master's thesis, ISA, 2017. http://hdl.handle.net/10400.5/14850.
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Mestrado em Engenharia Florestal e dos Recursos Naturais / Instituto Superior de AgronomiaNo presente trabalho estudou-se a madeira de Quercus cerris (carvalho-da-Turquia) com origem em dois locais (Blinaja e Duboçak) do Kosovo, área caracterizada por possuir um clima continental. O estudo assentou em várias análises, tendo-se feito uma análise anatómica de vários parâmetros dimensionais dos vasos; um estudo dendroclimático, identificando sinais climáticos relevantes com recurso a técnicas dendrocronológicas e uma análise da dureza através da determinação da dureza de Brinell. Os resultados mostraram que ao nível da anatomia dos vasos o Q. cerris possui características semelhantes a outras espécies do mesmo género, como por exemplo o Q. faginea, verificando-se que com o aumento da idade o número de vasos tende a diminuir, enquanto que a frequência se mantém relativamente constante e a proporção apresenta um ligeiro aumento. Obtiveram-se relações significativas (p<0,01 e p<0,05) entre os vários parâmetros analisados. A análise dendroclimatológica efetuada demonstrou que, tal como acontece para o crescimento desta espécie em climas mediterrânicos, a precipitação do início da primavera do ano corrente e no mês de outubro do ano anterior tem influência no crescimento radial desta espécie, apesar da fraca qualidade das cronologias analisadas neste trabalho que não permitiram uma conclusão sólida quanto a estes fatores. Obteve-se um valor de dureza médio superior para a madeira da parcela de Blinaja (38,48 N.mm2) quando comparado com a parcela de Duboçak (33,90 N.mm2). Os valores obtidos permitiram classificar a madeira dos dois locais como apta para a utilização em todos os tipos de pavimento doméstico e em áreas comerciais com uso moderado
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Gallucci, Valeria. « Interferenze climatiche e selvicolturali nei dinamismi di accrescimento di Abies alba Mill. e Quercus cerris L. nell'Appennino centrale ». Doctoral thesis, Università Politecnica delle Marche, 2009. http://hdl.handle.net/11566/242262.
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LO, GIUDICE VALENTINA. « Characterization of particleboards produced with Orange (Citrus sinensis L.) and Turkey oak (Quercus cerris L.) wood species using Modified Starch as adhesive ». Doctoral thesis, Università degli studi della Basilicata, 2022. http://hdl.handle.net/11563/156566.
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The continuing rise in raw material prices imposes the search for new raw materials with low economic competition. Generally, wood species utilized in particleboards (PBs) production are either softwoods like red fir, spruce and pine, or hardwoods like beech, poplar and birch. In recent years, several investigations into the potential advantages of using annual plants, fast-growing species and agricultural residues in the PBs production and on their performances as a raw material for PBs have been conducted. The present research focused on developing PBs produced with wood branches of Orange tree (Citrus sinensis L.) from crops and Turkey oak (Quercus cerris L.) wood residues from forest stand. Orange tree crops predominate the southern part of Italy, and Turkey oak forests are widespread along the Apennine mountain, especially in Basilicata Region. The management of both wood species produces a large amount of biomass often burned in the field or sometimes shredded and left into the soil to increase the organic matter, or used for energy purposes. Generally, PBs are manufactured with Urea-Formaldehyde (UF) as a binder, known as a toxic substance for human health. In this research Corn Starch modified with glutardialdehyde (MS) was promoted as a low environmental impact adhesive. PBs produced with orange and oak wood particles and using two types of adhesives, UF and MS, were compared and evaluated in terms of mechanical properties, such as modulus of elasticity (MOE), modulus of rupture (MOR), and internal bond strength (IB), and physical properties, such as thickness swelling (TS) and water absorption (WA). The obtained data were statistically analyzed using analysis of variance (ANOVA) and Duncan’s mean separation tests. All panels produced with UF adhesive showed good mechanical performances. Panels produced with the mixture of UF and MS showed acceptable MOE and IB values, complying with the minimum requirements of the standard EN 312:2004 for P2 panels type, namely non-structural panels including furniture for use in dry areas. TS values met also the requirement for P3 panels type intended for use in humid conditions, according to the standard EN 312:2004, but only in the case of the panels produced with UF adhesive. The use of MS has negatively affected the physical properties (TS and WA) and resistance to bending (MOR). However, the produced panels showed good performance for indoor applications, where dimensional stability is not a strict requirement.
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BERTOLASI, BRUNO. « Variabilità genetica ed analisi del flusso genico in popolazioni di Quercus cerris ed Ulmus minor ». Doctoral thesis, 2010. http://hdl.handle.net/2158/546264.
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Vilím, Stanislav. « Schopnost tvorby sekundární koruny u vybraných taxonů dřevin ». Doctoral thesis, 2012. http://www.nusl.cz/ntk/nusl-249323.
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This dissertation thesis deals with ability of secondary crown formation after opening a canopy and secondary crown utilization in landscape architecture. The ability of different taxa of trees to form a secondary crown after opening a canopy is genetically conditioned and influenced by the specific terms of habitat, tree age, physiological state of the individual and the specific characteristics of the individual. As a model plant for this dissertation thesis was chosen a representative of the Quercus L. genus which is very frequently used in landscape architecture. Specifically, Quercus cerris L. taxon was chosen which is grown in forest stands of Lednice-Valtice Cultural Landscape as a monoculture. Field research was conducted in forest stand edges of Forest management unit Židlochovice, namely in forest district Valtice. In this forest district were found suitable sites that meet the condition of chosen evaluation methodology, allowing comparable statistical evaluation. Enough suitable forest stand edges were found that were selected for the experiment. To the topic of secondary crown formation after opening a canopy and practical utilization of secondary crown is paid only little attention in specialized publications and in both basic and applied research. This thesis brings knowledge that can significantly contribute to the development and importance of field Landscape architecture in contemporary society. The thesis brings a lot of new information and relationships that occur during tree crown regeneration when opening a canopy. These findings can be used for example during the regeneration of untended objects of garden art monuments and other objects of landscape architecture. The results may also help in the conversion of forest stands to different objects of landscape architecture both in urban and rural settlements. The results allow modeling the development of woody plant vegetation elements in these objects. It is clear that arbitrary regenerative ability of secondary crown formation and thus the replacement of the primary crown is not sufficient but it is always necessary to respond on this ability of regeneration by various means of tree care measures so that the whole intention reaches the optimal result. The results indicate that primary or secondary woody plant vegetation element opening a canopy is able to regenerate in order to increase its landscaping value or to increase its dendrological potential of the compound vegetation element. Knowledge can also be used for regeneration of trees on the newly created forest stand edges, historical parks or other compound woody plant vegetation elements.
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Vieira, Pedro Gonçalo Simões. « Produção de extratos bioativos a partir de resíduos de Quercus cerris por extração supercrítica com solventes verdes ». Master's thesis, 2018. http://hdl.handle.net/10773/24408.
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Esta dissertação teve como objetivo estudar a produção e caracterização de extratos ricos em compostos bioativos (nomeadamente fridelina) a partir de cortiça de Quercus cerris. Realizaram-se extrações Soxhlet e extrações sólido-líquido (SLE) em descontínuo com metanol, etanol, diclorometano e éter de petróleo, assim como extração supercrítica (SFE) com dióxido de carbono modificado (por adição de etanol). Os extratos produzidos foram caracterizados por FTIR-ATR e GC-MS e o método de escalonamento multidimensional (MDS) foi aplicado para comparação dos mesmos. Realizou-se uma otimização experimental de SFE, usando um desenho fatorial de experiências do tipo Box-Behnken e a metodologia de superfícies de resposta.
O rendimento total de extração (𝜂Total) máximo foi obtido para o ensaio Soxhlet com metanol (𝜂Total = 13.8 wt.%) e o rendimento mínimo foi obtido para extração sólido-líquido em descontínuo com éter de petróleo (𝜂Total = 0.35 wt.%). Registou-se uma variabilidade significativa dos valores de 𝜂Total, marcada pelos rendimentos superiores para extração com solventes polares, nomeadamente metanol e etanol. No caso da extração supercrítica, 𝜂Total variou de 1.2 wt.% no ensaio SFE3 (50 ℃, 2.5 wt.% EtOH, 5 g min−1) até 1.7 wt.% no ensaio SFE4 (60 ℃, 2.5 wt.% EtOH, 8 g min−1). Em termos de concentração em fridelina (𝐶Friedelin), os resultados oscilaram entre 41.3 wt. % (Soxhlet com diclorometano) e 5.4 wt. % (SLE em descontínuo com éter de petróleo). Os melhores resultados em termos de 𝐶Friedelin foram os que envolveram solventes pouco polares/apolares. Os ensaios SFE atingiram resultados de 𝐶Friedelin melhores do que a maioria dos ensaios de extração Soxhlet e sólido-líquido em descontínuo, o que confirma a interessante seletividade do processo para a fridelina. A análise MDS destacou a maior proximidade química entre os extratos alcoólicos e a biomassa, e entre os extratos de solventes apolares ou pouco polares e a fridelina pura.
Para a otimização experimental de SFE da cortiça Q. cerris, as condições que maximizam 𝜂Total (2.2 wt.%) e 𝛼F,nF (3.3 para t = 8.0 h) são valores máximos de 𝑇 (60 ℃), teor de etanol (5 wt.%) e de caudal de CO2 (11 g min−1). De registar os valores de seletividade superior a 1.0 no espaço experimental estudado, o que confirma que a fridelina é removida seletivamente por SFE. No caso de 𝐶Friedelin, o valor máximo (38.2 wt.%) foi obtido para a combinação de baixa temperatura (40 ℃), ausência de cossolvente (0 wt.% EtOH) e menor caudal (5 g min−1). Em definitivo, as condições ótimas dependerão de qual o principal objetivo da extração: um extrato rico numa maior diversidade de compostos (maior 𝜂Total) ou em compostos alvo como a fridelina (maior 𝐶Friedelin).
No geral, este trabalho fornece argumentos importantes para a produção de extratos ricos em fridelina a partir da cortiça de Quercus cerris, através da tecnologia SFE no âmbito do conceito de biorrefinariaThe present work studied the production and characterization of extracts rich in bioactive compounds (namely friedelin) from Quercus cerris cork. Soxhlet and batch solid-liquid extraction (SLE) with methanol, ethanol, dichloromethane and petroleum ether were carried out, as well as supercritical fluid extraction (SFE) using modified carbon dioxide (by addition of ethanol). The produced extracts were characterized by FTIR-ATR and GC-MS, and multidimensional scaling (MDS) was applied to compare them. The optimization of SFE was performed using Box-Behnken design of experiments and response surface methodology. The maximum total extraction yield (𝜂Total) was attained for the Soxhlet extraction with methanol (𝜂Total = 13.8 wt.%) and the minimum was attained in batch SLE with petroleum ether (𝜂Total = 0.35 wt.%). A significant variability of 𝜂Total values was evident, marked by the higher yields obtained with polar solvents, namely methanol and ethanol. For the supercritical fluid extractions, 𝜂Total ranged from 1.2 wt.% for run SFE3 (50 ℃, 2.5 wt.% EtOH, 5 g min−1) to 1.7 wt.% for run SFE4 (60 ℃, 2.5 wt.% EtOH, 8 g min−1). For friedelin concentration (𝐶Friedelin), the results ranged from 41.3 wt.% (Soxhlet with dichloromethane) to 5.4 wt.% (batch SLE with methanol). The best performing assays on 𝐶Friedelin were those involving weakly polar/non-polar solvents. The SFE assays provided 𝐶Friedelin results better than most Soxhlet and batch SLE experiments, which confirms the interesting selectivity to friedelin (𝛼F,nF). MDS analysis highlighted the chemical proximity between the alcoholic extracts and the biomass, and between the weakly or non-polar solvent extracts and pure friedelin. For the experimental optimization of SFE of Q. cerris cork, the conditions that maximize 𝜂Total (2.2 wt.%) and 𝛼F,nF (3.3 at t = 8.0 h) were the maximum values of 𝑇 (60 ℃), ethanol content (5 wt.%) and CO2 flow rate (11 g min−1). In fact, the selectivity values were higher than 1.0 anywhere within the studied experimental space, which shows that friedelin can be removed selectively over all the other compounds by SFE. For friedelin concentration, the maximum (𝐶Friedelin= 38.2 wt.%) was attained for the combination of a lower temperature (40 ℃), no cosolvent (0 wt.% EtOH) and lower CO2 flow rate (5 g min−1). The optimal conditions depend on what is the main goal of extraction: an extract enriched in a higher diversity of compounds (higher 𝜂Total) or in a target compound like friedelin (higher 𝐶Friedelin). On the whole, this work provides strong arguments towards the production of friedelin enriched extracts from Quercus cerris cork through SFE technology, under the biorefinery concept
Mestrado em Engenharia Química
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SALVATORI, ELISABETTA. « Rischio da ozono e stress climatico in alcune cenosi forestali costiere del Lazio meridionale ». Doctoral thesis, 2008. http://hdl.handle.net/11573/918625.
Texte intégralChapitres de livres sur le sujet "Quercus cerri"
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Pavlovic, P., M. Mitrovic et R. Popovic. « Decomposition of quercus Farnetto Ten. and quercus Cerris L. Leaf Litter Under Natural Forest Conditions ». Dans Progress in Botanical Research, 361–64. Dordrecht : Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5274-7_83.
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Macchia, F., V. Cavallaro, F. Vita et G. Sburlino. « Acorn Dormancy and Aridity as Factors of Quercus Cerris L. Distribution ». Dans Responses of Forest Ecosystems to Environmental Changes, 633–34. Dordrecht : Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2866-7_91.
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Bobinac, M., et D. Vilotić. « Morphological-Anatomical Characteristics of Turkey Oak (quercus Cerris L.) Offspring Depending On Light Intensity In Regeneration Areas ». Dans Progress in Botanical Research, 595–98. Dordrecht : Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5274-7_136.
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Bellatreche, Ladjel. « Horizontal Data Partitioning ». Dans Handbook of Research on Innovations in Database Technologies and Applications, 199–207. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-242-8.ch023.
Texte intégralRésumé :
Horizontal data partitioning is the process of splitting access objects into set of disjoint rows. It was first introduced in the end of 70’s and beginning of the 80’s (Ceri et al., 1982) for logically designing databases in order to improve the query performance by eliminating unnecessary accesses to non-relevant data. It knew a large success (in the beginning of the 80’s) in designing homogeneous distributed databases (Ceri et al., 1982; Ceri et al., 1984; Özsu et al., 1999) and parallel databases (DeWitt et al., 1992; Valduriez, 1993). In distributed environment, horizontal partitioning decomposes global tables into horizontal fragments, where each partition may be spread over multiple nodes. End users at the node can perform local queries/transactions on the partition transparently (the fragmentation of data across multiple sites/processors is not visible to the users.). This increases performance for sites that have regular transactions involving certain views of data, whilst maintaining availability and security. In parallel database context (Rao et al., 2002), horizontal partitioning has been used in order to speed up query performance in a sharednothing parallel database system (DeWitt et al., 1992). This will be done by both intra-query and intra-query parallelisms (Valduriez, 1993). It also facilitates the exploitation of the inputs/outputs bandwidth of the disks by reading and writing data in parallel. In this paper, we use fragmentation and partitioning words interchangeably.
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Sabatti, M., G. E. Scarascia Mugnozza, R. Valentini et A. del Lungo. « Water relations and water transport in coppice vs. single stem Quercus cerris L. trees ». Dans Water Transport in Plants under Climatic Stress, 191–204. Cambridge University Press, 1993. http://dx.doi.org/10.1017/cbo9780511753305.018.
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