636 resultados para polpação kraft


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This paper concerns about the durability of new material in construction. It is noteworthy the fact that increases increasingly searching for alternative materials that do not depend only of natural resources and at the same time be an alternative for reuse of industrial waste. Since the construction materials have a long life and a high cost of civil works and maintenance, it is crucial to estimate the behavior of a new product. Thus , this work discuss the durability of mixed mortar lining , made with waste from the process Kraft pulp production , known as dregs and grits , in partial replacement of sand. Tests were conducted to simulate conditions as adverse environments of constant heat and fire, with the aim of analyzing the behavior of mortar mixed matched the behavior of standard mortar

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The new market, focused on sustainability and other environmental concerns, refers to innovations that seek alternative forms of production. In pulp and paper bleaching alternative reagents are studied, for example, hydrogen peroxide, in partial substitution of chlorine dioxide in order to reduce the formation of organochlorines. In this context, this study examined the burden of hydrogen peroxide (H2O2) on alkaline extraction stage (stage Ep) required for the bleaching of pulp with eucalyptus kraft pulp, pre-oxygen delignified to obtain equivalent brightness at 90 ± 0.5% ISO, as well as its effect on quality of pulp produced. The pulp was bleached by the sequence D(Ep)DP, with the application of factor kappa of 0.14 and varying the concentration of hydrogen peroxide in Ep stage three, five, seven and nine kilograms of reagent per ton of pulp absolutely drought. The final P stage was optimized with the use of six, nine and twelve pounds of hydrogen peroxide per ton of absolutely dry pulp to achieve the required brightness. The quality of the pulp produced was analyzed based on the kappa number, the brightness and the viscosity. The methods were performed according to standards set by the standard TAPPI (Technical Association of the Pulp and Paper Industry). The best result was obtained using the following D0Ep(7)D1P(6), which showed a viscosity of 19.9 cP, 89.6% ISO brightness, consumption of 94.9 kg / t of reagents and reagent costs of US$ 28.15, because it showed better pulp quality for a lower cost compared to the others. It was found that the greater the amount of hydrogen peroxide in alkaline extraction, the lower the kappa number and increased the amount of residual hydrogen peroxide. The higher the charge of hydrogen peroxide in Ep stage, the lower the need for hydrogen peroxide in the final P stage, reducing the cost of bleaching

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Pós-graduação em Ciência Florestal - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The air part of the cassava is a residue which presents possibilities of being used as a non-wooden raw material in the production of pulp due to the fact that its 81 % of the adult plants air part, besides having high availability and presenting a high concentration of fibers. Studies were developed with the purpose of producing the pulps through the kraft process, which is a mix of the Na2S and NaOH in water heated up to the temperature of 160º C for about 90 minutes to the extraction of lignin. The paper sheets obtained in the practices went through an experimenting process. Studies related to the paper characteristics were accomplished in order to assess its use in the visual communication through printing techniques, silk screen, pictures and others graphical processes. The research results are able to conclude the utilization viability of this material in graphics communication.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The species Artemisia annua L. (Asteraceae) is native to China and has artemisinin as its main active component, substance that is considered a potent antimalarial drug. With the increased interest in natural active principles, studies related to post-harvest and storage of vegetable material become important for better conservation of its phytotherapic properties. Therefore, the present study had as objectivedefine the best storage conditions to preserve and keep the quality of phytotherapic drugs. Leaves of A. annua dried were stored for six months in polyethylene bags wrapped in Kraft paper and packed in four treatments: at ambient condition, refrigerated at 4 ± 2 oC, using normal packing, and using vacuum packing. Samples were taken for microbiological, moisture content, and level of artemisinin analyses before the experiment begun and at 30, 90, 120 and 180 days. The results of microbiological tests showed no significant contamination, as well as the moisture content of the stored (biological) material, which remain between 5% and 10%, keeping within acceptable parameters. The ambient without vacuum treatment (SVA) was the treatment that better maintained the sample stability during 180 days, however, the refrigerated without vacuum (SVR) showed greater efficiency to conserve the content of artemisinin.

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The goal of this article was to evaluate the surface characteristics of the pine fibres and its impact on the performance of fibre-cement composites. Lower polar contribution of the surface energy indicates that unbleached fibres have less hydrophilic nature than the bleached fibres. Bleaching the pulp makes the fibres less stronger, more fibrillated and permeable to liquids due to removal the amorphous lignin and its extraction from the fibre surface. Atomic force microscopy reveals these changes occurring on the fibre surface and contributes to understanding the mechanism of adhesion of the resulting fibre to cement interface. Scanning electron microscopy shows that pulp bleaching increased fibre/cement interfacial bonding, whilst unbleached fibres were less susceptible to cement precipitation into the fibre cavities (lumens) in the prepared composites. Consequently, bleached fibre-reinforced composites had lower ductility due to the high interfacial adhesion between the fibre and the cement and elevated rates of fibre mineralization.

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Data visualization techniques are powerful in the handling and analysis of multivariate systems. One such technique known as parallel coordinates was used to support the diagnosis of an event, detected by a neural network-based monitoring system, in a boiler at a Brazilian Kraft pulp mill. Its attractiveness is the possibility of the visualization of several variables simultaneously. The diagnostic procedure was carried out step-by-step going through exploratory, explanatory, confirmatory, and communicative goals. This tool allowed the visualization of the boiler dynamics in an easier way, compared to commonly used univariate trend plots. In addition it facilitated analysis of other aspects, namely relationships among process variables, distinct modes of operation and discrepant data. The whole analysis revealed firstly that the period involving the detected event was associated with a transition between two distinct normal modes of operation, and secondly the presence of unusual changes in process variables at this time.

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O crescente interesse pelo uso de combustíveis renováveis nos últimos anos fez com que culturas oleaginosas, como a mamona, se tornassem importante objeto de estudo. No entanto, para a instalação de campos desta cultura, é imprescindível o uso de sementes de alta qualidade. O objetivo da pesquisa contida neste trabalho foi verificar a eficiência do teste de raios X na avaliação da qualidade de sementes de mamona após a colheita e armazenamento. Três lotes de sementes da cv. 'IAC-2028' (provenientes, respectivamente, dos racemos primário, secundário e terciário) e dois lotes da cv. 'Guarani' (lotes comerciais com sementes de todos os racemos misturados) foram avaliados de acordo com a morfologia interna pelo teste de raios X, na intensidade de 20 kV por 60 segundos de exposição. Posteriormente, as sementes radiografadas foram submetidas ao teste de germinação de modo a relacionar a morfologia interna das sementes com as respectivas plântulas normais, anormais ou sementes mortas. Após seis meses de armazenamento acondicionadas em sacos de papel Kraft, em condições não controladas de temperatura e umidade relativa do ar, amostras dessas sementes foram novamente avaliadas pelo teste de raios X. O teste de raios X é eficiente para avaliar a morfologia interna das sementes e seus reflexos no potencial fisiológico.

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Forskning vad gäller självhjälpsgrupper och dess faktiska verkan är överlag begränsad och trots flera års forskning finns det fortfarande ingen behandling som ger mycket goda resultat för många patienter med anorexi. Vetenskaplig utvärdering av olika behandlingsmetoder saknas i stor utsträckning och en genomgång av den vetenskapliga litteraturen visar att det inte finns några läkemedel med dokumenterad effekt vid anorexi. Varför bildas självhjälpsgrupper? Varför räcker det inte med de professionella behandlingsmodellerna? Dessa frågor ämnar jag att finna svar på i min uppsats. Jag har forskat kring professionella behandlingsmetoder samt självhjälp. Mina kärnfrågor i uppsatsen är: vilka olika professionella behandlingsmetoder finns och vad är självhjälp? Jag har valt en kvalitativ ansats på min uppsats. Jag vill beskriva, förklara och jämföra självhjälpsgrupper för anorexi och deras sätt att se sjukdomen och hur de arbetar för att ta sig ur den. Detta i förhållande till professionella behandlingsmetoder. Mina bakgrundsstudier med förklaringsmodeller av anorexi och tillgängliga professionella behandlingsmodeller har jag gjort genom en systematisk genomgång. Min studie görs enligt kvalitativ metod och genom en systematisk beskrivning. Jag har också gjort en systematisk sökning av de tillgängliga litteraturer som finns på biblioteket respektive Internet. Självhjälpsgrupper bör ses som ett komplement till de professionella behandlingsmetoderna snarare än ett alternativ, och man bör inte utesluta en professionell behandling för att istället vara med i en självhjälpsgrupp. Däremot bör man absolut inte underskatta den kraft och styrka det kan ge, att träffa andra människor i samma situation. Att samtala om det gemensamma problem man har, stötta varandra och känna gemenskap är en stark drivkraft i kampen att bli frisk från anorexi

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The thesis focuses on Karl Kraus’s rewritings of some Shakespeare plays and copes with the concepts of “translation” and “quotation” as commensurable forms of intertextuality. Building his Shakespeare’s Bearbeitungen as a montage of quotations of previous German translations, Karl Kraus creates a new kind of hybrid intertextuality that goes beyond the boundaries between quotation and translation. In my opinion, Karl Kraus understands quotation and translation as spatial concepts: in his rewritings he puts Shakespeare’s text into his geometrical and critical “perspective”. The thesis focuses also on the evolution of quotation and translation in Karl Kraus’s work: even maintaining their satirical and destruens function, they develop an “affirmative” role and are used in order to redefine the literary canon. The thesis investigates this form of intertextuality from a comparative point of view, referring to the translation studies (Hermans, Bassnett, Lefevere, Apel, Berman, Meschonnic), theories of intertextuality (Genette, Barthes, Worton, Orr), studies on quotation and montage (Compagnon; Möbius, Hage), and studies on Karl Kraus (Kraft, Ribeiro, Scheichl, Fischer, Timms, Canetti and the famous essay of Walter Benjamin). It also contains a survey of Theater der Dichtung’s historical framework and several comparisons between Karl Kraus’s and other early 20th translations of Shakespeare’s plays.

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Zusammenfassung Kooperativität bei Atmungsproteinen bedeutet eine Änderung der O2-Affinität während der Beladung mit O2 und läßt sich durch die Wechselbeziehung zwischen O2-Beladung und Konformation beschreiben. In dieser Arbeit wurde das 24-mere Hämocyanin der Vogelspinne Eurypelma californicum bzgl. Beladung und Konformationen sowohl auf der Ensemble- wie auch auf der Einzel-Molekül-Ebene charakterisiert. EnsembleDie Bindung von O2 an Hämocyanine ist mit einer drastischen Abnahme der Fluoreszenz-Quantenausbeute verbunden. Durch Vergleich von theoretisch und experimentell bestimmten Quantenausbeuten konnte gezeigt werden, daß die Löschung auf Förster-Transfer zurückzuführen ist, und daß kein Einfluß der Oligomerisierung, Protein-Konformation, Beweglichkeit oder Tierart besteht. Die Konformation von Hämocyaninen konnte mit Crosslinkern im oxy- und deoxy-Zustand fixiert werden. Die Charakterisierung der Produkte führte zu einer neuen Vorstellung, wie unterschiedliche Affinitäten realisiert sein können. Hierbei kommt der Dynamik der Protein-Matrix eine entscheidende Rolle zu. Einzel-MoleküleMittels Zwei-Photonen-Anregung konnten erstmalig einzelne Proteine über ihre intrinsische Tryptophan-Fluoreszenz nachgewiesen werden. Zum einen gelang es, Modellsysteme mit nur 340 Trp abzubilden, andererseits konnte die Diffusion einzelner Hämocyanine (148 Trp) mit Hilfe der Fluoreszenz-Korrelationsspektroskopie nachgewiesen werden.Einzelne Hämocyanine konnten durch Adsorption und mildes Eintrocknen an verschiedenen Oberflächen immobilisiert werden. Mittels Atomarer Kraft-Mikroskopie (AFM) ließen sich individuelle Hämocyanine abgebilden, wobei Details der Quarärstruktur aufgelöst werden konnten.

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Die Arbeit befasst sich mit den Änderungen der Resonanzparameter von Schwingquarzen, die durch Kontakte mit festen Körpern an der Oberfläche hervorgerufen werden (Quarz als kontaktmechanische Sonde). Bei Kontakt zwischen (weichen) Gold-Oberflächen tritt ein Peak bei der Dämpfung auf, der mit Reibung in Verbindung gebracht wird.Zur Bestimmung der Resonanzparameter wurde das „ring-down“ Verfahren angewendet, bei dem der Quarzresonator zunächst auf seiner Resonanzfrequenz angeregt wird und dann die frei abklingende Quarzschwingung mit einer exponentiell abfallenden Sinusschwingung angefittet wird. Eine Unterteilung der Abklingkurve in einzelne Segmente liefert bei Kontakt eine amplitudenabhängige Resonanzfrequenz und Abkling-Konstante. Mittels Störungsrechnung wurden daraus explizit nichtlineare Federkraft-Auslenkung und Reibungskraft-Geschwindigkeit Relationen berechnet.Bei Gold-Gold Kontakten zeigt sich ein sublinearer Anstieg der elastischen Kraft mit der Auslenkung, und ein linearer Anstieg der Reibungskraft mit der Geschwindigkeit, der im Gegensatz zu Kontakten zwischen harten und spröden Oberflächen oft erst ab einer kritischen Geschwindigkeit einsetzt. Ist eine Thiol-Monolage in der Kontaktfläche vorhanden, so verringert sich die kritische Geschwindigkeit stark.Das Analyseverfahren wurde weiterhin auf die Untersuchung granularer Medien angewendet, die sich von Festkörpern und Flüssigkeiten durch das Auftreten von Spannungspfaden und Scherinstabilitäten unterscheiden. Dieses Verhalten ist bei kubischen Körnern stärker ausgeprägt als bei Kugeln.