O licor negro, cuja composição majoritária é de lignina, é o principal subproduto gerado após a obtenção de polpa celulósica. Este polímero natural é caracterizado pela elevada massa molecular (MM) e composição aromática. Processos físico-químicos são empregados na fragmentação da lignina com o objetivo de obter compostos aromáticos, cuja fonte não renovável é oriunda de derivados do petróleo. A biodegradação da lignina, causada pela ação de enzimas ligninolíticas fúngicas pode prover compostos aromáticos de baixo peso molecular, como fenóis e antioxidantes, utilizados em diversos segmentos industriais. O objetivo deste trabalho foi estudar a modificação estrutural da lignina causada por fungos basidiomicetos coletados de mata nativa e campos de reflorestamento de eucalipto. Os ensaios de biodegradação foram inicialmente conduzidos utilizando-se 10 espécies de fungos, cultivados em duas concentrações de licor negro (10% e 15%, v/v). No ensaio com licor menos concentrado, utilizaram-se 10 espécies, e no ensaio com licor 15% utilizou-se somente a espécie Pycnoporus sanguineus. As análises realizadas para o estudo da modificação estrutural da lignina foram: espectroscopia na região do infravermelho (FTIR/ATR), cromatografia líquida de gel filtração e espalhamento de raios-X a baixo ângulo (SAXS). P. sanguineus e espécies de fungos do gênero Trametes possuem elevada capacidade de consumir a lignina presente no licor 10%, após 14 dias. A atividade de enzimas ligninolíticas de P. sanguineus foi investigada nas duas concentrações de licor. No licor 10%, observou-se elevada atividade das enzimas ligninolíticas manganês peroxidase (MnP), lacase e peroxidases; somente a MnP foi detectada com maior atividade no licor 15%. Análises de Demanda Bioquímica de Oxigênio (DBO) indicaram que o licor negro 10% biodegradado por P. sanguineus possui elevada carga de DBO, sendo tóxico a Daphia magna e Hydra attenuatta. Análises de metabólitos produzidos pelos fungos no licor negro 10% por cromatografia gasosa acoplada à espectrometria de massas (GC-MS) indicaram, principalmente, a produção de açúcares e álcoois em concentrações não muito diferentes dos seus respectivos controles. Embora os fungos sejam capazes de reduzir a massa molecular da lignina presente no licor negro, compostos derivados da sua fragmentação podem sofrer reações de condensação ou repolimerização, contribuindo, eventualmente, para elevar sua massa molecular / Black liquor which the bulk content is lignin, is the main product generated after obtaining cellulose pulp. This natural polymer is characterized by high molecular weight (MW) and aromatic compounds. Physical-chemical processes can be employed to fragment lignin and to produce aromatic compounds to replace those from non-renewable sources such as petroleum. Biodegradation of lignin can provide low molecular weight compounds, such as phenols and antioxidants, which may be employed in various industrial processes. The aim of this work was to investigate the structural modification of lignin caused by basidiomycetes fungi, obtained from native forest and Eucalyptus fields. The biodegradation assay was done with10 fungi species cultivated with two concentrations of black licor (10% and 15%, v/v). The assay with 10% liquor, 10 species of basidiomycete fungi were used, and in the assay with 15% liquor, it was used only Pycnoporus sanguineus. The analyses carried out to determine the structural modification of lignin were: infrared spectroscopy (FTIR/ATR), liquid chromatography gel filtration and small angle X-ray scattering (SAXS). P. sanguineus and fungi of Trametes genera had high capacity to consume the lignin content in the 10% liquor, after 14 days of cultivation. After that, P. sanguineus was selected for assays of ligninolytic enzymes activities in the two liquor concentrations. High activities of manganese peroxidase (MnP), laccase and peroxidase were detected in the 10% liquor, whereas in the concentration of 15% only high MnP activity was detected. Biochemical Oxygen Demand, analysis (BOD) indicated that the biodegraded liquor had high BOD load, and it was toxic to Daphia magna and Hydra attenuata. Metabolites produced by the fungi in the liquor 10% were analysed by gas chromatography-mass spectrometry (GC-MS), which indicated mainly the production of sugars and alcohols in concentrations not far from their respective controls. Although the fungus is able to decrease molecular weight of lignin, its fragments derivatives can undergo condensation or repolymerization reactions, contributing, eventually, to increase its molecular weight

Este trabalho teve como objetivo analisar os cavacos de dimensões reduzidas inseridos em cozimentos que se utilizam de menores tempos e maiores temperaturas, de maneira a se obter as bases para o estabelecimento de um novo processo e/ou a otimização dos sistemas atualmente utilizados em escala industrial. Amostras de cavacos de referência (3,6 mm, obtidas pelo processo convencional de picagem) e de cavacos com espessura de 0,5 mm, 1 mm e 2 mm (obtidas por um gerador de partículas), do híbrido de Eucalyptus urophylla x Eucalyptus grandis com 7 anos foram analisadas quanto à densidade básica, composição química e morfologia das fibras. Após a caracterização, os materiais foram submetidos à polpação kraft pelo processo convencional e foram testados três níveis de fator H com quatro níveis de álcali ativo de maneira a se estabelecer uma equação que representasse o processo e pudesse ser utilizada em cozimentos futuros. Através das equações obtidas foi possível calcular os parâmetros de rendimento depurado, álcali ativo residual, álcali ativo consumido, teor de sólidos secos, fator H e álcali ativo em função de um número kappa 18. Os resultados mostram que a densidade básica, a composição química e a morfologia das fibras da madeira não foram afetadas pelo processo de picagem. No entanto, a densidade a granel foi afetada pela espessura dos cavacos, sendo de 0,037, 0,081, 0,110 e 0,141 g.cm-³ para os cavacos de 0,5 mm, 1 mm, 2 mm e 3,6 mm respectivamente. No processo de polpação, as espessuras se comportaram de maneira semelhante, no entanto, a espessura de 2 mm apresentou o melhor número kappa para o fator H de 451, o de maior interesse, com o mesmo rendimento que as demais espessuras. Na análise de regressão, a espessura de 2 mm apresentou melhor rendimento, menor teor de sólidos e menor fator H (de 461), compatível com o que se pretende utilizar em processos de polpação com tempo reduzido de cozimento. / The objective of this work was to evaluate the performance of thin chips inserted on a short time and higher temperatures in cooking process, to obtain the basis for the establishment of a new process and / or the optimization of the currently systems used on an industrial scale. Samples of the reference chips (3,6 mm obtained by the conventional process of chipping) and thin chips with 0,5 mm, 1 mm and 2 mm (obtained by a particle generator) of the Eucalyptus urophylla x Eucalyptus grandis hybrid with 7 years of age had their density, chemical composition and fibers morphology evaluated. After the characterization, the materials were submitted to conventional kraft pulping process and three levels of H factor with four levels of active alkali were tested to establish an equation to represent the process that can be used on future cookings. Yield, residual active alkali, consumed active alkali, dry solids, H factor and active alkali were calculated through equations, according to a kappa number 18. The results show that the basic density, chemical composition and morphology of the wood fibers were not affected by the chipping process. However, the bulk density of 0,037, 0,081, 0,110 and 0,141 g.cm-³ for the 0,5 mm, 1 mm, 2 mm and 3,6 mm chips, respectively, was affected by the chip thickness. On the pulping process, the different chips had the same behavior, however, 2 mm chips showed the best kappa number to H factor 451, with the same yield as the other thickness. On the regression analysis, the 2 mm chips showed better performance, lower solids content and lower H factor (461), consistent with a short time pulping process.

O presente trabalho teve como objetivo avaliar a utilização das madeiras de Corymbia citriodora, Corymbia torelliana e seus híbridos para a produção de celulose kraft branqueada. Para isso, as madeiras destas espécies e híbridos foram caracterizadas tecnologicamente e submetidas ao processo kraft de polpação e branqueamento, sendo comparadas à madeira de E. grandis x E. urophylla, utilizada como referência tecnológica. Ao todo, foram avaliadas sete diferentes materiais genéticos do gênero Corymbia: dois materiais de C. citriodora, com 8 e 18 anos de idade, um material de C. torelliana, com 15 anos, e quatro híbridos destas espécies, com 7 anos de idade. A madeira de E. grandis x E. urophylla apresentava 6 anos de idade. Inicialmente, as madeiras das diferentes espécies e híbridos foram caracterizadas sendo, em seguida, submetidas a um processo modificado de polpação kraft. As polpas foram deslignificadas com oxigênio e branqueadas através da sequência DA Ep D1 P visando alvura final de 89,5 ± 0,5% ISO, e tiveram suas características físico-mecânicas determinadas. O impacto das diferentes madeiras no dimensionamento de uma fábrica de celulose também foi avaliado. Os resultados mostram que as madeiras do gênero Corymbia apresentam alta densidade básica e baixo teor de lignina, além de fibras com maior comprimento, menor largura, menor diâmetro do lume, maior espessura de parede e maior fração parede em relação à madeira de E. grandis x E. urophylla. Os processos de polpação de C. citriodora (madeira de 8 anos) e E. grandis x E. urophylla demandam menor carga alcalina e fator H, resultando nos maiores rendimentos, sendo que os menores consumos específicos de madeira foram observados para as madeiras de C. citriodora. A deslignificação com oxigênio é mais eficiente para as polpas do gênero Corymbia em comparação à polpa de E. grandis x E. urophylla. No branqueamento, as polpas C. citriodora (madeira de 8 anos) e E. grandis x E. urophylla são as que demandam menor aplicação de reagentes químicos para atingir determinada alvura. Em comparação às polpas das demais espécies e híbridos avaliadas, as polpas branqueadas da espécie C. citriodora apresentam alto volume específico, baixa resistência à passagem do ar, alta capilaridade, baixo índice de retenção de água e alta resistência ao rasgo, características que recomendam a utilização da polpa desta espécie para a produção de papéis de alta absorção (tissue). Já as polpas de C. torelliana x C. citriodora apresentam baixo volume específico, alta resistência à passagem do ar e baixa capilaridade, enquanto as polpas de E. grandis x E. urophylla e de um dos materiais de C. citriodora x C. torelliana se destacam por apresentar as maiores resistências à tração, rasgo e estouro. No dimensionamento de uma fábrica de celulose, as madeiras dos híbridos de C. citriodora e C. torelliana que apresentam a espécie C. torelliana como genitor feminino (C. citriodora x C. torelliana) demandam maior atenção, principalmente nas áreas da caldeira de recuperação e caustificação, uma vez que apresentam alta demanda de álcali e alta geração de sólidos em comparação aos demais materiais genéticos. / The present work aimed to evaluate the use of the woods of Corymbia citriodora, Corymbia torelliana and their hybrids on bleached kraft pulp production. Woods from these species and hybrids were technologically characterized and submitted to kraft pulping process and bleaching. These woods were compared to E. grandis x E. urophylla, which was used as technological reference. Seven different genetic materials from Corymbia were analyzed: two materials of C. citriodora, with 8 and 18 years-old, one material of C. torelliana, with 15 years-old, and four hybrids of these species, with 7 years-old. The wood of de E. grandis x E. urophylla had 6 years-old. Initially, the different woods were technologically characterized and then submitted to a modified kraft pulping process. The pulps were delignified with oxygen and bleached through a DA Ep D1 P bleaching sequence until 89,5 ± 0,5% ISO of brightness. The bleached pulps had their physical-mechanical characteristics evaluated. The impact of these different woods in a pulp mill dimensioning was also evaluated. The results show that the woods of Corymbia genus present high basic density, low lignin content and fibers with higher length, lower width, lower lumen width, higher wall thickness and higher wall fraction if compared to E. grandis x E. urophylla. The pulping of C. citriodora and E. grandis x E. urophylla demands lower alkali charge and H factor, resulting in higher yields, while the lowest wood specific consumption was observed to C. citriodora\'s woods. The oxygen delignification is more efficient for Corymbia\'s pulps than for E. grandis x E. urophylla. On bleaching, the pulps of C. citriodora (wood with 8 years-old) and E. grandis x E. urophylla are those that demand the lowest chemical reagents charges to achieve the determined brightness. The bleached pulps of C. citriodora present high specific volume, low air passage resistance, high capillarity, low water retention value and high tear index. Based on these characteristics it is possible to recommend this species to tissue papers production. The pulps of C. torelliana x C. citriodora present low specific volume, high air passage resistance and low capillarity, while the pulp of E. grandis x E. urophylla and one of the hybrids of C. citriodora x C. torelliana stands out for presenting the higher tensile, tear and burst indexes. In a pulp mill dimensioning, the woods of C. torelliana x C. citriodora demands higher attention, mainly on recovery boiler and causticizing, for presenting high alkali demand and high solids generation in comparison to the other genetic materials.

Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2018-05-24T14:48:48Z No. of bitstreams: 2 Ana Carolina Feil Kmetzski.pdf: 812447 bytes, checksum: 2d488034b2c65ee35de1c24cddd5d26d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-05-24T14:48:48Z (GMT). No. of bitstreams: 2 Ana Carolina Feil Kmetzski.pdf: 812447 bytes, checksum: 2d488034b2c65ee35de1c24cddd5d26d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-02 / The pulp and paper industry is a globally expanding segment. Focusing on economic profitability and environmental preservation, the paper industry has been looking for viable alternatives to enhance the Kraft process. The chlorine bleaching conventional method, although highly efficient, causes environmental pollution due to the discharge of organochlorine compounds into effluents. The use of enzymes microorganisms, especially xylanases, has emerged as a promising alternative for the bleaching processes. These enzymes could considerably help reduce environmental pollution, reducing the use of organochlorine compounds, which acts as a bleaching chemical for pulps and causes the formation of organochlorine residual compounds, which are extremely harmful to the environment and give the pulp industry one of the most polluting. Therefore, studies that provide the use of enzymatic processes in the Kraft pulp bleaching stage by the industry will always be relevant, mainly in order to reduce the discharge of contaminating material into effluents. In this context, this review will discuss the characteristics of the constitution of the raw material for the pulp kraft paper industry, as well as the enzymatic properties of fungal xylanases cellulase-free tested on cellulose pulps, kraft and waste straw, which have potential for future use by paper industry. / A indústria de papel e celulose é um segmento em ampla expansão mundial. Com foco na rentabilidade econômica e preservação ambiental, a indústria papeleira tem buscado alternativas viáveis para aprimorar a etapa do processo da polpa Kraft. O método convencional de branqueamento da polpa com cloro, embora altamente eficiente, causa poluição ambiental devido à descarga de compostos organoclorados em efluentes. A utilização de enzimas de micro-organismos, em especial as xilanases, têm surgido como uma alternativa promissora para o processo de branqueamento da polpa Kraft. Essas enzimas podem auxiliar consideravelmente na redução da poluição ambiental, com diminuição da utilização de compostos organoclorados, que atuam como agentes químicos branqueadores das polpas e ocasionam a formação de compostos residuais que são extremamente prejudiciais ao meio ambiente e conferem às indústrias de celulose a condição de ser uma das mais poluidoras. Em razão disso, estudos que proporcionam o uso de processos enzimáticos na cadeia de branqueamento da polpa Kraft pela indústria serão sempre relevantes, principalmente com o intuito de reduzir a descarga de material contaminante em efluentes. Dentro desse contexto, essa revisão abordará sobre as características da constituição da matéria-prima para obtenção da polpa celulose pela indústria papeleira, bem como, as propriedades enzimáticas das xilanases fúngicas isentas de celulases testadas em polpas de celulose, kraft e palhas de resíduos que apresentam potencial para uso futuro pelas indústrias papeleiras.

<p>The essential thing about breaks has been in relation to time, body, movement, force and room during my examination. Through conversations high-school students from two schools have taken part in this study. The examination is based on conversations with the students and has focused on students’ experiences of breaks, and is also carried through by the method of phenomenology. The results of my studie show that students - during their breaks - experience a feeling of allways heading for something and also that time seem to exist in three levels: filled time, non-filled time and flow regarding of time. Since time has such important influence in my examination, there is also results that show that a break of 20 minutes is the optimal break; the essence of the phenomen.</p>

The present work reports on the electron–vibron coupling in large organic molecules and particularly on the intermolecular interaction in molecular condensates. The optical and electrical properties of these organic systems are in the focus of attention due to their crucial importance for the development of (hybrid) organic electronic devices. In particular, the charge transport mechanism and hence the interaction between condensed molecules is a matter of debate [1–4]. In order to shed light on this interaction, the spectroscopic signatures of isolated molecules in the gas phase and their condensed counterparts have been studied. The applied technique, near–edge x–ray absorption fine structure (NEXAFS) spectroscopy, is a local probe with high chemical selectivity, well suited for the investigation of the electronic structure of molecular valence levels [5]. In the experimental part, the experimental set–up developed in this work is described with special attention to the characteristic issues of gas phase measurements, energy calibration and the subsequent data evaluation. The high quality gas phase and solid state NEXAFS spectra are analysed with respect to energy positions, shape and intensity of the sharp pi*–resonances characteristic for these aromatic molecules. Where applicable, a detailed Franck–Condon (FC) analysis of the vibronic fine structure has been performed, yielding additional information on the changes that occur upon solid state formation. Together with former results on vibrational features in large organic molecules, this information has been used to investigate the correlation of vibrational energies in the ground and electronically excited state. We find a relatively good agreement with other empirical studies on vibronic structures in photoelectron spectroscopy (PES) spectra of small molecules [6]. The molecular compounds investigated are in general believed to interact via weak van–der–Waals forces only. The present results however reveal distinct differences between the spectra of the gas and solid phase that can not be explained within the context of a mere interaction by dispersive forces. In detail, differential red–shifts of 0.1 to 0.3eV of transitions assigned to the aromatic system have been observed in the C–K spectra of benzene–tetracarboxylic acid dianhydride (BTCDA), 1,4,5,8–naphthalene–tetracarboxylic acid dianhydride (NTCDA), and 3,4,9,10–perylene–tetracarboxylic acid dianhydride (PTCDA) upon solid state formation. From BTCDA to PTCDA the shift increases, indicating an improving intermolecular interaction with molecular size or a closer molecular packing. In contrast, all transitions assigned to the anhydride carbon atom (C1) do not show any shift. For the O–K spectra, small changes in relative intensity have been observed for BTCDA and NTCDA. In case of PTCDA, a blue–shift of up to 0.2eV is evident for the OB 1sLEMO+1 transition. Theoretical models for the intermolecular interaction have been proposed in this work, based on a change of molecular geometry and interaction of adjacent molecules in the ground and excited state, respectively. While an interaction of adjacent molecular orbitals may explain the experimental findings for one particular molecule, this model falls short for a comprehensive explanation of all three dianhydrides. For an interaction in the excited state, the excitonic coupling with the neighbours attached at an angle, quantum chemical calculations yield no significant change in peak positions for NTCDA. Unfortunately, results for the stacked neighbours as well as the larger compound PTCDA are still lacking. For tris (8–quinolinol) aluminum (Alq3), the observed peak–shifts are restricted to just one unoccupied orbital, the LEMO+2, which is mainly localised at the phenoxide side of the quinolinol ligands. Although the shifts differ for the individual edges, the main interaction can therefore be assigned to this orbital. In summary, NEXAFS spectroscopy, if performed with great care in terms of experimental details and data analysis especially for the gas phase data, provides very detailed and highly interesting data on the changes of the electronic structure of organic molecules upon condensation. The present data can be applied as a reference for further experimental and (highly desired) theoretical investigations, which are needed for a comprehensive understanding of the complex interaction mechanisms between organic molecules. / Die vorliegende Arbeit beschäftigt sich mit der Kopplung vibronischer und elektronischer Anregungen in großen organischen Molekülen. Die Mechanismen des Ladungstransportes und damit auch die zu Grunde liegende Wechselwirkung dieser Moleküle im Festkörper sind immer noch Gegenstand aktueller Diskussionen [1–4]. Mit der Untersuchung der spektroskopischen Eigenschaften von einerseits freien, also gasförmigen Molekülen, andererseits von (stark) wechselwirkenden Molekülen im Festkörper soll mit der vorliegenden Arbeit ein Beitrag zum besseren Verständnis der intermolekularen Wechselwirkung geleistet werden. Als Methode wurde die Röntgen–Nahkanten–Spektroskopie (NEXAFS) angewandt, die durch ihre chemische Selektivität lokale Informationen über die elektronische Struktur der Valenzzustände der untersuchten organischen Moleküle liefern kann [5]. Im experimentellen Teil wird eine Apparatur zur Untersuchung der organischen Moleküle in der Gasphase, die im Rahmen dieser Arbeit entwickelt wurde, vorgestellt. Das Hauptaugenmerk liegt dabei auf den Besonderheiten der Gasphasenmessungen sowie der Energiekalibrierung und anschließenden Datenauswertung. Die qualitativ hochwertigen Spektren werden nach Gesichtspunkten der energieposition, Form und Intensität der für die organischen Moleküle typischer Weise sehr scharfen pi* Resonanzen ausgewertet. Für Spektren mit gut aufgelöster Feinstruktur wurde die darunter liegende Schwingungsstruktur mit Hilfe einer Franck–Condon Auswertung untersucht, woraus sich weitere Informationen über die Einflüsse im Festkörper gewinnen ließen. Die dabei gesammelten Daten wurden zusammen mit den Ergebnissen früherer Untersuchungen der Schwingungsfeinstruktur organischer Moleküle herangezogen, um den Zusammenhang zwischen den Schwingungsenergien im elektronisch angeregten und im Grundzustand zu bestimmen. Dabei ergab sich eine gute Übereinstimmung mit empirischen Untersuchungen der Schwingungsstruktur kleiner Moleküle anhand von Photoelektronenspektroskopie (PES) [6]. Die vorliegenden Ergebnisse zeigen ausgeprägte Unterschiede in den Spektren der verschiedenen Phasen, die sichnicht im Rahmen einer Wechselwirkung durch rein dispersive Kräfte erklären lassen. Im Einzelnen traten zwischen den Gasphasen– und Festkörperspektren der C–K Kanten von 1,2,4,5–Benzoltetracarbonsäuredianhydrid BTCDA, 1,4,5,8–Naphthalintetracarbonsäuredianhydrid NTCDA und 3,4,9,10–Perylentetracarbonsäuredianhydrid PTCDA Rotverschiebungen von 0,1 bis 0,3eV auf. Die entsprechenden elektronischen Übergänge sind jeweils dem aromatischen System zugeordnet und zeigen in der Reihe von BTCDA zu PTCDA eine zunehmende Verschiebung. Dies deutet auf eine verstärkte Wechselwirkung bei größeren Molekülen, beziehungsweise bei einer dichteren Packung hin. Übergänge die dem Anhydrid Kohlenstoff (C1) zugeordnet sind, zeigen jedoch keinerlei Verschiebung. Die Spektren der O–K Kanten von BTCDA und NTCDA weisen lediglich eine leichte Veränderung der relativen Intensitäten auf. Im Falle von PTCDA wurde eine Blauverschiebung von bis zu 0,2eV für den OB 1s LEMO+1 Übergang beobachtet. In dieser Arbeit werden einige theoretische Modelle vorgeschlagen, die auf einer Änderung der Molekülgeometrie bzw. einer Wechselwirkung der Molekülorbitale sowohl im Grund– als auch im angeregten Zustand basieren. Betrachtet man lediglich eine einzelne Molekülsorte, so liefert z.B. eine Wechselwirkung der Orbitale benachbarter Moleküle eine zufriedenstellende Erklärung für die beobachteten Änderungen. Bei einer umfassenden Betrachtung aller Moleküle der Dianhydrid Gruppe scheitert dieses Modell jedoch. Erste quantenchemische Berechnungen der Wechselwirkung mittels einer exzitonischen Kopplung der NTCDA Moleküle mit ihren gewinkelten Nachbarn lieferten keine nennenswerten Verschiebungen der Resonanzenergien. Weiterführende Rechnungen dieser Art stehen jedoch für die gestapelten Nachbarn sowie für das größere PTCDA noch aus. Bei dem Molekül Tris(8-chinolinol)aluminium Alq3 lassen sich alle beobachteten Verschiebungen einem Orbital, dem LEMO+2 zuordnen. Obwohl die Verschiebungen für die verschiedenen Absorptionskanten unterschiedlich sind, lässt sich die Wechselwirkung des Moleküls somit diesem Orbital, das an der Phenolat Seite des Liganden lokalisiert ist, zuordnen. Zusammenfassend lässt sich sagen, dass die Röntgen–Nahkanten Spektroskopie hochinteressante und sehr genaue Informationen über die Änderung der elektronischen Struktur organischer Moleküle beim Übergang in die kondensierte Phase liefern kann. Die Ergebnisse dieser Arbeit können als eine Referenz für zukünftige experimentelle und theoretische Untersuchungen betrachtet werden. Für ein umfassendes Verständnis der komplexen Wechselwirkung zwischen organischen Molekülen sind diese weiteren Untersuchungen unabdingbar.

Skridskoåkning är en viktig färdighet för ishockeyspelare. Syftet med denna studie var att undersöka olika variabler inom kinetik och kinematik och dess association med hastighet på skridskoåkning över en kort distans. Tolv manliga elit ishockeyspelare deltog i studien. Pedar mobile system inläggssulor placerades i båda skridskorna. Deltagarna genomförde tre maximala försök där det åkte så snabbt de förmådde mellan den förlängda mållinjen och den närmsta blålinjen. Den bästa tiden av de tre försöken användes vid analysen. Kraftdata insamlades för att räkna ut medelkraft, högsta kraft, relativa medelkraft, relativa högsta kraft, impuls, kontakttid, rörelsefrekvens för skridskoskären och asymmetri mellan extremiteterna, därefter korrelerades data mot åktiden. Frekvensen på skären visade en signifikant korrelation med åktiden (r= -0,586; p&lt;0,05). Övriga variabler visade inget samband med åktiden. Enligt denna studie så är rörelsefrekvens en viktig faktor för att ishockeyspelare ska kunna generera skridskohastighet över en kort sträcka. / <p>Godkännande datum: 2019-09-03</p>

In the context of this thesis, the novel method soft X-ray energy-dispersive NEXAFS spectroscopy was explored and utilized to investigate intermolecular coupling and post-growth processes with a temporal resolution of seconds. 1,4,5,8- naphthalene tetracarboxylic acid dianhydride (NTCDA)multilayer films were the chosen model system for these investigations. The core hole-electron correlation in coherently coupled molecules was studied by means of energy-dispersive near-edge X-ray absorption fine-structure spectroscopy. A transient phase was found which exists during the transition between a disordered condensed phase and the bulk structure. This phase is characterized by distinct changes in the spectral line shape and energetic position of the X-ray absorption signal at the C K-edge. The findings were explained with the help of theoretical models based on the coupling of transition dipole moments, which are well established for optically excited systems. In consequence, the experimental results provides evidence for a core hole-electron pair delocalized over several molecules. Furthermore, the structure formation of NTCDA multilayer films on Ag(111) surfaces was investigated. With time-resolved and energy-dispersive NEXAFS experiments the intensity evolution in s- and p-polarization showed a very characteristic behavior. By combining these findings with the results of time-dependent photoemission measurements, several sub-processes were identified in the post- growth behavior. Upon annealing, the amorphous but preferentially flat-lying molecules flip into an upright orientation. After that follows a phase characterized by strong intermolecular coupling. Finally, three-dimensional islands are established. Employing the Kolmogorov-Johnson-Mehl-Avrami model, the activation energies of the sub-processes were determined. / Im Rahmen dieser Arbeit wurden die Möglichkeiten der neuartigen Methode energiedispersive Röntgen-Nahkanten-Absorptions-Spektroskopie für die Untersuchung intermolekularer Wechselwirkungen und zeitabhängiger Prozesse während der Strukturbildung aufgezeigt. Als Modellsystem wurden hierbei 1,4,5,8- Naphthalin-Tetracarboxyls¨aure-Dianhydrid-(NTCDA-) Filme verwendet. Es wurde die Rumpfloch-Elektronen-Wechselwirkung kohärent gekoppelter Moleküle mittels energiedispersiver Röntgen-Nahkanten-Absorptions-Spektroskopie untersucht. Dabei wurde eine Übergangsphase gefunden, die während der Ausbildung einer langreichweitigen Ordnung zeitlich zwischen der ungeordneten und der Volumenstruktur auftritt. Diese Übergangsphase zeichnete sich durch eine charakteristische Änderung der spektralen Linienform und ihrer energetischen Position bei Messungen an der C K-Kante aus. Die experimentellen Befunde lassen sich mit Hilfe theoretischer Modelle erklären, welche die Kopplung von Übergangsdipolmomenten beschreiben. Diese theoretischen Konzepte sind bei optisch angeregten Systemen etabliert. Die experimentellen Ergebnisse zeigen den über mehrere Moleküle delokalisierten Charakter des Rumpfloch-Elektron-Paars. Zudem wurde die Strukturbildung von mehrlagigen NTCDA-Filmen auf Ag(111) untersucht. Zeitabhängige energiedispersive NEXAFS-Experimente mit s- und p-polarisiertem Licht zeigten ein charakteristisches Verhalten. In Kombination mit zeitabhängigen Photoemissionsmessungen wurden bei der Strukturbildung verschiedene Unterprozesse gefunden. Nach erwärmen der Probe richten sich die ursprünglich flach orientierte Moleküle zunächst auf. Im Anschluss folgt eine Aggregation der Moleküle in einer Phase mit starker intermolekularer Kopplung. Letztendlich bildet sich die bekannte dreidimensionale Filmstruktur aus. Anhand des Kolmogorov-Johnson-Mehl-Avrami Modells konnte die Aktivierungsenergie für die verschiedenen Unterprozesse ermittelt werden.

Ett stort antal studier har visat att samma vardagsuppfattningar om fysikfenomen är återkommande bland studenter i olika länder och på olika utbildningsnivåer. Newtons tredje lag är bland det mest utmanande att förstå i fysikens innehåll. Syftet med denna litteraturstudie är att jämföra vad studier visat om svårigheter med att förstå Newtons tredje lag och forskningsfrågorna är: Vilka faktorer påverkar förståelsen för Newtons tredje lag? Hur har dessa faktorer påverkat förståelsen och vad har det haft för konsekvenser? Artiklarna som ligger till grund för resultatet har tagits fram med hjälp av en systematisk informationssökning och en urvalsprocess med bestämda inkluderingskriterier. I materialanalysen framträdde tre faktorer som påverkar förståelsen av N3 (Newtons tredje lag) och vi har valt att benämna dessa som naiva uppfattningar, kontext och språk. Dessa faktorer ledde till svårigheter med att identifiera N3-kraftparet - kraft och motkraft - samt att skilja N3-kraftparet från jämviktskrafter. Studierna visade även att människors uppfattningar inte överensstämde med den vetenskapligt accepterade idén om N3, utan att de istället uppfattade en ojämlikhet mellan krafterna på det ena eller andra sättet. Litteraturstudiens resultat diskuteras i relation till undervisning och styrdokument.

The essential thing about breaks has been in relation to time, body, movement, force and room during my examination. Through conversations high-school students from two schools have taken part in this study. The examination is based on conversations with the students and has focused on students’ experiences of breaks, and is also carried through by the method of phenomenology. The results of my studie show that students - during their breaks - experience a feeling of allways heading for something and also that time seem to exist in three levels: filled time, non-filled time and flow regarding of time. Since time has such important influence in my examination, there is also results that show that a break of 20 minutes is the optimal break; the essence of the phenomen.