Dissertations / Theses on the topic 'Mott materials'
To see the other types of publications on this topic, follow the link: Mott materials.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Mott materials.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Lantz, Gabriel. "Ultrafast electron dynamics in Mott materials." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112014/document.
Abstract:
Les isolants de Mott sont un exemple parfait de l’impact des corrélations électroniques locales sur les propriétés macroscopiques des matériaux. En variant légèrement le dopage ou la pression, un métal peut se transformer en un isolant. Ces propriétés peuvent être modifiées de manière très rapide en plaçant ces matériaux loin de l'équilibre. Nous avons étudié un prototype de Mott-Hubbard, V2O3 dopé en Cr, en utilisant l'état de l’art des techniques pompe-sonde, à savoir la photoémission résolue en angle, la réflectivité optique, la spectroscopie THz, et la diffraction des rayons X. La réponse électronique du système, après une excitation laser femtoseconde, qui a été maintenue pour chaque expérience à une longueur d'onde de 800 nm, a pu être déconvoluée de la réponse du réseau. Une étude comparative de ces réponses transitoires démontre un fort couplage électron-phonon dans ce prototype de matériau fortement corrélé. Avant thermalisation, le poids spectral est transféré de la bande de Hubbard inférieure vers le gap de Mott. Sur une échelle de temps plus long un état métastable est stabilisé par un changement structural. Pour mieux comprendre la réponse transitoire des isolants de Mott, nous avons également étudié un autre composé de Mott, BaCo1-xNixS2. Les tendances générales des isolants de Mott après photoexcitation ont été analysées en utilisant un modèle à deux orbitales. Nous interprétons que le remplissage du gap comme un changement spécifique des occupations orbitalesMott insulators are a perfect example of how local electronic correlations can change macroscopic properties of materials. Varying slightly the doping or the pressure can transform a metal to an insulator. These properties can be modified extremely rapidly by driving these materials far from equilibrium. We have investigated the model Mott-Hubbard material Cr-doped V2O3 using state of the art pump-probe techniques, namely angle resolved photoelectron spectroscopy, optical reflectivity, THz time-domain spectroscopy, and X-ray diffraction. We were able to unequivocally disentangle the electronic and the lattice response of the system to a femtosecond laser excitation, which was kept in all cases at a wavelength of 800 nm. We present a comparative study of these transient responses, which demonstrates the strong electron-phonon coupling of this strongly correlated model material. We show that before thermalization, spectral weight is transferred from the lower Hubbard band towards the Mott gap. On a longer time scale a metastable state is stabilized by the lattice structure. To further understand the transient response of Mott insulators, we have also studied another Mott compound, BaCo1-xNixS2. The general trends of photoexcitation in Mott insulators are analyzed using a two orbital model. We argue that the filling of the gap can be due to a change of the specific orbital fillings
2
Scheiderer, Philipp [Verfasser], and Ralph [Gutachter] Claessen. "Spectroscopy of Prototypical Thin Film Mott Materials / Philipp Scheiderer ; Gutachter: Ralph Claessen." Würzburg : Universität Würzburg, 2019. http://d-nb.info/1193423899/34.
3
Winograd, Emilio. "Orbital-selectivity in strongly correlated fermionic systems. From materials to cold-atoms." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112031.
Abstract:
Cette thèse se concentre sur des aspects multiorbitales des systèmes fermioniques fortement corrélés. En particulier, sur l'existence d'une différentiation orbitale dans laquelle la coexistence de caractère itinérant et localisé peut être associée à différentes orbitales. Cette problématique est examinée dans le contexte des atomes froids et des matériaux, offrant un pont entre les deux communautés.Dans la première partie de la thèse, nous donnons un aperçu du problème des corrélations fortes dans les matériaux, et nous introduisons le concept de 'transition de Mott sélective en orbitales'. Nous fournissons également les principaux outils pour comprendre comment les matériaux peuvent être simulés avec des atomes froids, et nous présentons des résultats importants liés à la transition métal-isolant de Mott. Les aspects techniques, basées sur la théorie du champ moyen dynamique sont également discutés, et la solution de deux principaux modèles de systèmes fermioniques fortement corrélés, à savoir le modèle d'Hubbard (HM) et le modèle de Falicov-Kimball (FKM), sont passés en revue.Ensuite, nous étudions en détail la physique de deux espèces fermioniques en interaction forte avec des masses différentes dans un réseau optique. Nous établissons les différentes phases (avec et sans ordre à longue portée) en termes de la force des interactions (U), du rapport des masses et de la température (T), et aussi nous discutons les variables thermodynamiques, qui sont pertinentes pour les expériences d'atomes froids. Nous montrons que dans la phase métallique (U inférieure à une valeur critique) et avec un certain degré de différence de masses, un 'crossover' apparaît entre un état métallique du type de liquide de Fermi à basse T, et un état avec différentiation orbital à haute T, où les fermions lourds se localisent tandis que les fermions légers restent itinérant. Par conséquent, nous proposons ce modèle minimal pour étudier la physique des systèmes qui présentent une différentiation orbitale avec des expériences d'atomes froids.Basé sur les propriétés du modèle étudié, nous proposons la 'chromatographie entropique' comme une nouvelle méthode pour refroidir des atomes fermioniques dans les réseaux optiques. Nous discutons son efficacité et ses limites, et fournissons quelques idées afin de les surmonter.Dans la dernière partie de la thèse, nous généralisons le modèle précédent aux matériaux corrélés à plusieurs bandes qui permet d'afficher la différentiation orbitale. Nous montrons que l'état de Mott sélectif en orbital peut être stable sous les distorsions du réseau, modélisées par une hybridation locale entre les orbitales. Cependant, l'état de Mott est caractérisé par un pseudo-gap, où les fluctuations de charge sont brusquement réduites, mais l'état reste compressible. En relation au modèle précédent, nous discutons le 'crossover' entre l'état métallique et l'état sélectif induit par des effets température, nous comparons nos résultats avec les expériences de photoémission, et nous prédisons ce qui se passerait dans les matériaux qui présentent une hybridation locale entre les bandesThis thesis focuses on multiorbital aspects of strongly correlated fermionic systems. In particular, it focuses on the existence of orbital differentiation in which coexistence of itinerant and localized character can be associated to different orbitals. This subject is discussed in the context of cold atoms and materials, providing a bridge between both communities.In the first part of the thesis, we give an insight into the problem of strong correlations in materials, and we introduce the concept of 'orbital-selective Mott transition'. We also provide the main tools to understand how materials can be simulated with cold atoms experiments, and we present important related results in the context of the metal-Mott insulator transition. The technical aspects, based on dynamical mean-field theory are also discussed, and the solution of two key models of strongly correlated fermionic systems, i.e., the Hubbard model (HM) and the Falicov-Kimball model (FKM), are reviewed.Then we study in detail the physics of two interacting fermionic species with different masses in an optical lattice. We establish the different phases (with and without long-range order) in terms of the interactions strength (U), mass ratio and temperature (T), and also discuss the thermodynamic variables, which are relevant in cold atoms experiments. We show that in the metallic phase (U below a critical value) and for some degree of mass imbalance, a crossover appears between a Fermi-liquid metallic state at low T, and an 'orbital-selective' state at higher T, where the heavy fermions effectively localize while the light species remain itinerant. Hence, we propose this minimal model for addressing orbital-selective physics with cold atoms experiments.Based on the properties of the studied model, we propose the 'entropic chromatography' as a new method for cooling fermionic atoms in optical lattices. We discuss its efficiency and limitations, and provide some ideas in order to overcome them.In the last part of the thesis we generalize the previous model to a model relevant for multiband correlated materials that can display orbital differentiation. We show that the orbital-selective Mott state can be stable under lattice distortions modeled by local hybridization between the orbitals. However, the Mott state is characterized by a pseudogap, where charge fluctuations abruptly reduce, but the state remains compressible. In connection with the previous model, we discuss the temperature-induced orbital-selective crossover in this problem, we compare our results with photoemission experiments, and predict what would happen in materials that display local hybridization between the bands
4
Sagaidak, Iryna. "Bi-functional materials combining energy storage and energy conversion from sunlight." Thesis, Amiens, 2019. http://www.theses.fr/2019AMIE0025.
Abstract:
La nature intermittente de l'énergie solaire est souvent résolue par un couplage entre le PV et une batterie. Notre approche plus fondamentale vise à développer des matériaux capables de combiner ces deux fonctions à l'échelle moléculaire. Des nanocristaux de TiO2 de 5 nm ont été synthétisés dans notre groupe, ce qui a permis une réaction quantitative de photorecharge sous illumination standard. Nous présentons ici une étude originale portant sur l'évolution des propriétés optoélectroniques et de la dynamique du transfert de charge dans une électrode de TiO2 à l'aide d'expériences spectroscopiques in operando effectuées pendant le fonctionnement de la batterie. L'augmentation de la valeur de la bande interdite et de l'absorbance a été observée lors de l'insertion du lithium dans TiO2. Un décalage négatif en énergie de la bande de conduction indique un potentiel plus oxydant des trous photogénérés dans le Li0.6TiO2 par rapport au TiO2 initial. En analysant les processus de recombinaison dans Li0.6TiO2, nous avons établi une compétition entre les processus ultra-rapides (gamme ps) de recombinaison directe et de transfert de charge vers Ti3+ dans Li0.6TiO2, ce qui limite potentiellement le rendement de la réaction de photorécharge. Cette étude a été étendue à d'autres matériaux d'insertion généralement utilisés dans les batteries lithium-ion (Li4Ti5O12, LiCoO2, LiFePO4, MoO3, etc.). Les positions de bord de bande, la bande interdite, le type de porteurs de charge et leur concentration ont été mesurées et rassemblées dans une base de données. Basé sur ces résultats, la possibilité de photorécharge induite par la lumière a été évaluée et les premiers résultats discutésThe problem of intermittent nature of solar energy is often addressed by the traditional coupling of the PV and battery units. Our more fundamental approach targets the development of materials able to combine solar energy conversion and storage at the molecular level. The 5 nm anatase TiO2 nanocrystals were synthesized in our group affording a quantitative photorecharge reaction by a sole contribution of illumination. Here, we present a study of the evolution of the optoelectronic properties and dynamics of charge transfer in TiO2 electrode using in situ / in operando experiments performed during the battery functioning (UV-visible, Mott-Schottky, fluorescence spectroscopy). The increase of the bandgap value and the rise of absorbance are observed upon lithium insertion into TiO2. A negative shift of the conduction band indicates a more oxidizing potential of the photogenerated holes in Li0.6TiO2 compared to TiO2. By analysis of the recombination processes in TiO2 upon lithium insertion, we established a competition of the ultra-fast (ps range) processes of direct recombination and charge transfer towards Ti3+ in Li0.6TiO2, potentially limiting the yield of the photorecharge reaction. This study was extended to other insertion materials typically used in lithium-ion batteries (Li4Ti5O12, LiCoO2, LiFePO4, MoO3, etc.). The measured band edge positions, band gap, charge carrier type and concentration were gathered into a database, based on which the fundamental evaluation of the possibility of the light-induced photorecharge was conducted. The first results of the photoelectrochemical study of chosen materials are also discussed
5
Leriche, Raphaël. "Unconventional superconductivity in quasi-2D materials with strong spin-orbit coupling." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS577.
Abstract:
La réalisation de supraconducteurs topologiques constitue un des principaux enjeux actuels de la physique de la matière condensée. Il a en effet été prédit que ces systèmes devaient abriter des fermions de Majorana. Ces fermions de Majorana disposent à la fois d’une statistique non-abélienne et, du fait de leur origine topologique, d’une robustesse face au désordre local, ce qui les rend très attrayants pour des applications en informatique quantique. Une approche susceptible de conduire à de la supraconductivité topologique consiste à considérer des systèmes supraconducteurs à fort couplage spin-orbite et brisant la symétrie d’inversion. C’est dans cette optique que, dans le cadre de cette thèse, j’ai effectué des mesures de microscopie et spectroscopie par effet tunnel sur des matériaux quasi-bidimensionnels : (LaSe)1,14(NbSe2)2 et Sr2IrO4.J’ai tout d’abord étudié les propriétés électroniques du matériau incommensurable (LaSe)1,14(NbSe2)2, proche parent du composé dichalcogénure de métaux de transition 2HNbSe2. (LaSe)1,14(NbSe2)2 est une hétérostructure faite d’alternances de biplans NbSe2 à géométrie prismatique trigonale et de biplans de LaSe avec une structure de sel de roche. Le fort couplage spin-orbite ainsi que la non-centrosymétrie présents dans les plans NbSe2 font de (LaSe)1,14(NbSe2)2 un potentiel candidat pour de la supraconductivité topologique. Dans cette thèse, je présente des résultats de spectroscopie montrant que la structure électronique de (LaSe)1,14(NbSe2)2 est similaire à celle de la monocouche de NbSe2 avec un dopage de type électron accompagné par un déplacement du potentiel chimique de 0,3 eV, jusqu’alors inégalé. J’ai également pu démontrer la nature quasi–bidimensionnelle de (LaSe)1,14(NbSe2)2 et notamment la présence d’un fort couplage spin-orbite de type Ising. De plus, la faible robustesse de la supraconductivité vis à vis du désordre non magnétique couplée à des mesures d’interférences de quasiparticules m’a permis de mettre en avant le caractère non conventionnel du paramètre d’ordre supraconducteur dans (LaSe)1,14(NbSe2)2. Cette étude permet d’envisager l’utilisationd’hétérostructures incommensurables telles que (LaSe)1,14(NbSe2)2 pour explorer la physique des dichalcogénures de métaux de transition dans la limite bidimensionnelle, pour laquelle de nombreuses études théoriques ont prédit une supraconductivité topologique. Dans cette thèse, je présente également une étude des effets du dopage sur les propriétés électroniques de l’oxyde d’iridium Sr2IrO4. Sr2IrO4 est un isolant de Mott non conventionnel puisqu’il doit cette propriété à la présence d’un fort couplage spin-orbite. Du fait d’une brisure locale de la symétrie d’inversion, certaines prédictions théoriques ont pu montrer que Sr2IrO4 devrait devenir un supraconducteur topologique une fois dopé. Ici, je montre qu’avec le dopage, Sr2IrO4 subit une transition de phase inhomogène à l’échelle nanométrique entre un état isolant de Mott et un état pseudo-métallique. Ce travail justifie la pertinence d’utiliser une sonde locale telle que le microscope à effet tunnel afin de venir compléter des résultats sur la physique de Mott obtenus par des méthodes intégratives comme la spectroscopie électronique résolue en angleThe realization of topological superconductors is one of the main current goals of condensed matter physics. It was indeed predicted that such systems should host Majorana fermions. These Majorana fermions possess both a non-Abelian statistics and, because of their topological origin, a certain robustness against local disorder, which makes them attractive for quantum computing applications. One approach likely to lead to topological superconductivity consists in considering superconducting systems with strong spin-orbit coupling and with broken inversion symmetry. It is in this framework that, during this thesis, I performed scanning tunneling microscopy and spectroscopy measurements on quasi-2D materials : (LaSe)1,14(NbSe2)2 and Sr2IrO4. I first studied the electronic properties of misfit compound LaNb2Se5, which is a parent of transition metal dichalcogenide 2H-NbSe2. (LaSe)1,14(NbSe2)2 is a heterostructure made out of alternations of NbSe2 bilayers with trigonal prismatic geometry and LaSe bilayers with rocksalt structure. (LaSe)1,14(NbSe2)2 is a potential candidate for topological superconductivity because of the presence of both a strong spin-orbit coupling and of broken inversion symmetry in NbSe2 planes. Here, I present spectroscopic results showing that the electronic structure of(LaSe)1,14(NbSe2)2 is very similar to the one of electron-doped monolayer NbSe2 with a shift of the chemical potential of 0,3 eV, priorly never reached. I could also demonstrate the quasi- 2D nature of (LaSe)1,14(NbSe2)2 and more particularly the presence of a strong Ising spinorbit coupling. Moreover, the observed weakness of superconductivity against non-magnetic disorder combined with quasiparticle interferences measurements allowed me to exhibit the unconventional nature of (LaSe)1,14(NbSe2)2 superconducting order parameter. This study opens the possibility to use misfit heterostructures such as (LaSe)1,14(NbSe2)2 to study thephysics of transition metal dichalcogenides in the 2D limit, for which many theoretical studies predict topological superconductivity. In this thesis, I also present a study on the effects of doping on the electronic properties of iridate compound Sr2IrO4. Sr2IrO4 is a spin-orbit induced Mott insulator. Because inversion symmetry is locally broken in Sr2IrO4, some theoretical predictions suggest that Sr2IrO4 should turn into a topological superconductor once doped. Here, I exhibit a nanometer-scaleinhomogeneous doping-driven Mott insulator to pseudo-metallic phase transition. This work further justifies the importance of using a local probe such as scanning tunnelling microscopy in order to complete results on Mott physics obtained by integrative methods like angle-resolved photoemission spectroscopy
6
Koussir, Houda. "Multiscale study of the electric field induced transition in the Mott phase of GaMo4S8 crystals and TaSe2 monolayers." Electronic Thesis or Diss., Université de Lille (2022-....), 2024. http://www.theses.fr/2024ULILN004.
Abstract:
Dans le domaine de la physique de la matière condensée, les isolants de Mott sont essentiels pour explorer des phénomènes électroniques complexes, ayant des implications significatives pour la supraconductivité à haute température et les liquides de spin quantiques. Cette thèse porte sur deux types d'isolants de Mott qui se distinguent l'un de l'autre par leur dimensionalité : des cristaux de GaMo4S8 et des monocouches de 1T-TaSe2.Après avoir introduit leurs propriétés dans le premier chapitre, le second chapitre traite des techniques utilisées pour caractériser ces matériaux à l'échelle locale, d'une part la microscopie et spectroscopie à effet tunnel pour mener une étude structurale et électronique et d'autre part la microscopie à effet tunnel à pointes multiples pour effectuer des mesures de transport.Cette dernière technique a notamment servi à analyser le transport dans GaMo4S8. Nous nous sommes alors intéressés à la réponse du matériau aux champs électriques externes, examinant le champ électrique seuil en fonction de la géométrie des électrodes et explorant l'évolution temporelle des temps de commutation en relation avec les distances inter-électrodes. L'obtention de transitions volatiles ouvre la voie à des applications telles que l'opération d'un microneurone à température ambiante.Pour mieux contrôler les propriétés de transition de phase des isolants de Mott, il est intéressant de considérer des systèmes bidimensionnels dans lesquels le passage du courant est confiné dans le plan du cristal. Aussi, le dernier chapitre se rapporte à la phase 1T du TaSe2, épitaxiée sur des substrats semi-conducteurs de phosphure de gallium (GaP). Comme le révèle l'étude réalisée par microscopie à effet tunnel à basse température, les monocouches de 1T-TaSe2 ne présentent pas seulement la modulation de la densité de charge (étoile de David) caractéristique de la phase onde de densité de charge, mais aussi un motif de Moiré original dû à l'interaction de la monocouche avec le substrat de GaP. Dans cette phase, caractérisée par spectroscopie tunnel, une bande interdite a été mise en évidence, signature de l'état isolant de Mott à basse température. L'état de Mott est corroboré par des mesures de transport dépendant de la température, qui indiquent la persistance de la phase isolante jusqu'à 400 kelvins. De plus, des mesures spectroscopiques à distance pointe-surface variable ont montré l'existence de transitions isolant-métal à basse température. L'observation de telles transitions permet d'envisager l'utilisation de cette hétérostructure à grande échelle comme candidat potentiel en tant que matériau neuromorphiqueIn the realm of condensed matter physics, Mott insulators are essential for exploring complex electronic phenomena, with significant implications for high-temperature superconductivity and quantum spin liquids. This thesis investigates two types of such materials, distinguished by their dimensionality : GaMo4S8 crystals and monolayer 1T-TaSe2.After presenting their properties in the first chapter, the second chapter addresses the local-scale characterization techniques used to characterize both materials, namely scanning tunneling microscopy and spectroscopy for structural and electronic studies, and multi-tip scanning tunneling microscopy for transport measurements. The latter technique was particularly employed to analyze transport in GaMo4S8. The study then delved into the material response to external electric fields, examining the threshold electric field in relation to the electrode geometry and exploring the temporal evolution of switching times in connection with inter-electrode distances. The achievement of volatile transitions opens prospects for applications such as the operation of a microneuron at room temperature.To enhance the control over phase transition properties of Mott insulators, it is beneficial to consider two-dimensional systems where the current flow is restricted within the crystal plane. The final chapter focuses on the 1T phase of TaSe2, epitaxially grown on gallium phosphide (GaP) semiconductor substrates. Low-temperature scanning tunneling microscopy studies reveal that 1T-TaSe2 monolayers exhibit not only the characteristic charge density modulation (Star of David) of the charge density wave phase but also a unique Moiré pattern due to the monolayer interaction with the GaP substrate. Scanning tunneling spectroscopy has identified a bandgap, hallmark of the Mott insulating state. This state is further substantiated by temperature-dependent transport measurements that show the persistence of the insulating phase up to 400 kelvins. Notably, spectroscopic measurements with varying tip-to-surface distances have unveiled insulator to metal transitions at low temperatures. The observation of such transitions suggests that this large-scale heterostructure could be a material of choice for neuromorphic applications
7
Forino, Paola Caterina. "Nuclear magnetic resonance study of the electron doped Dirac-Mott Insulator double perovskite Ba2Na(1-x)CaxOsO6." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Abstract:
Osmium-based materials exhibit unconventional magnetism due to the interplay between spin orbit coupling and strong electronic correlations.
In this thesis we investigate for the first time the effect of charge doping on the Dirac Mott insulator double perovskites Ba2Na(1-x)CaxOsO6 by using Nuclear Magnetic Resonance technique. We study in details the evolution of the magnetic phase diagram as a function of doping and applied magnetic field.
The system rapidly evolves from a canted to a collinear antiferromagnetic ground state with a monotonic increase of the magnetic transition temperature. Furthermore, the system remains insulating in the whole range of doping, despite the injection of extra electrons. This indicates that the Dirac-Mott insulating state of this material is unusually robust.
In particular, the results show an unexpected thermally activated charge dynamics which suggests the presence of polarons dominating the high temperature excitations of this Dirac-Mott insulator.
8
Boissy, Clément. "Transport de matière au sein du film passif : Développement d’une méthodologie sélective corrélant les Point Defect Model et les modèles descriptifs." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0136.
Abstract:
Le développement de la plaque bipolaire - PB -métallique nécessite une amélioration des propriétés du matériau qui la constitue. L'utilisation de l'acier implique une meilleure compréhension du film passif - FP. En effet, le cahier des charges de la PB demande une bonne conduction électronique ainsi qu'une longue durée de vie. L'amélioration de ces paramètres passe par une meilleure corrélation et compréhension entre les propriétés semi-conductrices et la résistance à la corrosion. La difficulté liée à l'étude de la passivation réside dans les nombreux phénomènes modifiant le comportement du film passif. De nombreux modèles présentés dans la littérature peuvent être utilisés pour caractériser la passivation. L'un des principaux, le Modèle de Défauts Ponctuels de D. D. Macdonald (Point Defect Model - PDM), décrit le FP à partir d'une série de réactions électrochimiques se déroulant à l'interface métal/oxyde et à l'interface oxyde/électrolyte. La réactivité est limitée par le transport de matière à travers l'oxyde. Après une étude bibliographique, ce phénomène semble être un paramètre discriminant dans le choix des modèles. Une méthode de sélection permettant une utilisation de chacun de ces modèles en fonction de leurs spécificités est proposée. Ainsi, cette méthode est basée sur la corrélation entre la mesure du transport de matière à partir des équations du PDM et l'analyse des Spectres d'Impédance Electrochimique (SIE). Le PDM caractérisant le transport de matière indépendamment de la SIE, il devient possible de déterminer le bien-fondé de la prise en compte de celui-ci dans les mesures de spectroscopie d'impédance électrochimique. L'évolution de la densité du porteur de charge majoritaire avec le potentiel de formation de l'oxyde permet d'accéder au coefficient de transport à partir des équations du PDM. Connaissant l'épaisseur de l'oxyde par des mesures XPS, la constante de temps et la fréquence caractéristique peuvent être déterminées. Sur la base de ces deux valeurs, un modèle descriptif d'analyse des spectres est sélectionné en évitant le sur-paramétrage. Cette méthode est appliquée d’abord à un matériau modèle, le chrome pur exposé à un milieu acide (pH 2), à différentes températures (30°C et 80°C). Elle valide la nécessité de la prise en compte du transport de matière à 80°C ainsi que la présence d'une surface composée d'une couche d'oxyde interne et d'une couche d'hydroxyde externe. Dans un second temps, cette méthode est utilisée sur un matériau industriel, un acier de type AISI 316L, à différents pH (1,2 et 3) et à différentes températures (30°C et 80°C). Elle a permis de décrire l'oxyde en surface comme une jonction p-n prenant en compte une couche riche en chrome interne avec un gradient de concentration de fer. Cette méthode a permis de caractériser de manière approfondie l'acier de type AISI 316L. Bien que ne concernant que le substrat, cette étape est déterminante dans l'amélioration des performances des PB métalliquesDevelopments in metallic bipolar plate, to apply more widely fuel cells, require an improved of the constitutive material. The use of stainless steel calls for a good understanding of the passive film. The required specifications are for good electrical conductivity and a long life-time. Those two parameters correspond to a correlation between the semiconductive properties and the good corrosion behavior. Nevertheless, the main problems of the passivity lie on the multiplicity of the phenomena that alter the passive film behavior. Numerous models described in the literature can be used to characterize the passivation. The Point Defect Model (PDM) describes the passivation through electrochemical reactions at the metal / oxide and at the oxide / electrolyte interfaces. The reactivity is limited by mass transport through the oxide. From the literature, those phenomena seems to be a discriminating parameter in the choice of a model. The selective method proposed allows us to use each model taking into account their specifics. This methodology is based on the correlation between the mass transport characterization, thanks to the PDM, and the analysis of the Electrochemical Impedance Spectroscopy (EIS). The PDM determines the transport coefficient apart from EIS measurements, so to validate the consideration of the mass transport during the analysis of the electrochemical impedance spectra. The evolution of the main charge carrier density as a function of the oxide formation potential allows us to calculate the transport coefficient from PDM equations. Thanks to the thickness of the oxide (determined by X-ray Photoelectron Spectroscopy), the time constant of the mass transport is determined. Based on this value, a descriptive model is used to analyze the EIS data, avoiding overparametrization. This method is applied first on a model material, pure chromium exposed to acidic solution (pH 2) at several temperatures (30°C and 80°C). It shows that the mass transport has to be taken into account at 80°C and the EIS model considers an inner chromium oxide layer and an outer chromium hydroxide. Secondly, the method is used to characterize an industrial material, AISI 316L stainless steel, at several pH (1, 2 and 3) and at several temperatures (30°C and 80°C). In this case, the oxide is describe as a p-n semiconductor junction with an chromium rich inner layer and an outer iron rich layer. The present methodology permits to deeply characterize the AISI 316L stainless steel. Even if this study concerns the substrate, this step is decisive to improve the performances of the metallic bipolar plates
9
Kamal, Abdelhamied Saber Suzan. "Synthesis and characterization of some nano-selenides and their applications in solar cells." Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/107389.
Abstract:
Resumen (Castellano)
El aumento del consumo de energía global junto con las preocupaciones ambientales ha
generado mucho interés por las fuentes de energía alternativas y limpias, como la energía solar
fotovoltaica. Los investigadores en la comunidad fotovoltaica han estado buscando formas de
reducir costos mientras mantienen o aumentan las eficiencias. Una mejor comprensión de los
materiales implicados es esencial para el rápido desarrollo de nuevas tecnologías. Las películas
delgadas I-III-VI2 ofrecen sistemas prometedores para lograr células solares de alta eficiencia a
un costo menor. De hecho, al adaptar la composición de los compuestos, es posible cambiar la
banda prohibida del material para captar la luz solar de manera más eficiente.
Esta tesis se centra en la preparación y caracterización del material de la capa absorbente,
especialmente las películas delgadas nanocristalinas y la consideración de las características
estructurales y eléctricas de dicha capa principal absorbente de células. La tesis examina cómo
las diferentes técnicas de preparación y uso del material podrían afectar las propiedades del
películas delgadas sintetizadas.
Películas delgadas CuInSe2 y CuInS2 se depositaron sobre sustratos de vidrio ITO usando la
técnica de electrodeposición en solución acuosa. Las películas electrodepositadas se
caracterizaron por difracción de rayos X (XRD), microscopía electrónica de barrido (SEM) y
análisis de rayos X de energía dispersiva (EDS). Se investigaron los efectos de recocido sobre
los precursores electrodepositados. La estructura de calcopirita de CuInSe2/CuInS2 mostró una
mejora de la cristalinidad después del tratamiento posterior de selenización/sulfurización en
atmósfera Se/S, respectivamente. Los estudios de XRD y SEM revelaron una mejora de la
calidad cristalina de las películas de CIS después de los tratamientos térmicos. Las propiedades
ópticas de las películas delgadas recocidas CuInSe2-Se y CuInSe2-S se han estudiado para
determinar el efecto del proceso de recocido en diferentes ambientes de selenio y azufre.
Además, modificamos el CuInxCryGa1-x-ySe2 de cobre indio, donde x = 0.4, y = (0.0, 0.1, 0.2,
0.3) la capa de superestrato por el proceso de recubrimiento por centrifugado. CuInxCryGa1-xySe2
donde x = 0.4, y = (0.0, 0.1, 0.2, 0.3) nanopartículas han sido sintetizadas en primer lugar
usando un método hidrotermal químico húmedo que se basa en un proceso térmico sin vacío
sin ningún proceso de selenización adicional. Introduciendo diferentes fuentes de metal en un
autoclave con etilenamina como solvente, se obtuvieron nanopartículas de CIGS a diferentes
temperaturas en un rango de 190-230 °C. Los resultados de la difracción de rayos X (XRD)
confirmaron la formación de una estructura de calcopirita CuInxCryGa1-x-ySe2 tetragonal.
Finalmente, se estudió el efecto de la temperatura de recocido en los materiales tipo Kesterita
(como el Cu2ZnSnS4) que son materiales de muy bajo costo y que no dañan el medio ambiente.
Estudiamos el crecimiento de las películas delgadas cuaternarias Cu2ZnSnS4 (CZTS) de
kesterita mediante un depósito electroquímico de un solo paso seguido de un recocido a baja
temperatura. La influencia de diferentes atmósferas de recocido a tiempos de recocido
constantes (t = 45 min) y parámetros de control de preparación fijos; es decir, concentración de
la solución de materiales de partida (sales de metales precursores), tiempo de deposición y
potencial de electrodeposición. Se estudiaron las propiedades estructurales, de composición,
morfológicas y ópticas, así como las propiedades fotoelectroquímicas.Abstract Increasing global energy consumption together with environmental concerns has led to much interest in alternative, cleaner sources of energy such as solar photovoltaic. Researchers in the solar cell community have been looking for ways to reduce costs while maintaining or increasing already high efficiencies. A fundamental understanding of the materials under consideration is essential to rapid development of new technologies. The I-III-VI2 thin films offer promising systems for achieving high efficiency solar cells at lower costs. In fact, by tailoring the chemistry of the compounds it is possible to change the bandgap of the material in order to collect sunlight more efficiently. First of all, this thesis focuses on absorber layer material preparation and characterization, especially nanocrystalline thin films and consideration of both structural and electrical characteristics of such main cell absorber layer.The thesis examines how different preparation techniques and material usage could affect the properties of the synthesized thin films (absorber layer). In this study CuInSe2 and CuInS2 thin films were deposited onto ITO glass substrate using the electrodeposition technique in aqueous solution. The electrodeposited films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDS). The annealing effects on the electrodeposited precursors were investigated. The chalcopyrite structure of CuInSe2/CuInS2 showed an enhancement of crystallinity after subsequent selenization/sulfurization treatment in Se/S atmosphere, respectively. XRD and SEM studies revealed a dramatic improvement of the crystalline quality of CIS films after annealing treatments. The optical properties of annealed CuInSe2-Se and CuInSe2-S thin films have been studied in order to determine the effect of annealing process in different selenium and sulfur atmosphere. In the second step we modified copper indium CuInxCryGa1-x-ySe2 where x=0.4, y= (0.0, 0.1, 0.2, 0.3)superstrate layer by spin coating process. CuInxCryGa1-x-ySe2 where x=0.4, y= (0.0, 0.1, 0.2, 0.3) nanoparticles have been synthesized firstly using a wet chemical hydrothermal method that is based on a non-vacuum thermal process without any additional selenization process. Introducing different metal sources in an autoclave with ethylenediamine as solvent, CIGS nanoparticles were obtained at different temperatures range 190-230°C. The X-ray diffraction (XRD) results confirmed the formation of a tetragonal CuInxCryGa1-x-ySe2 chalcopyrite structure. Finally, we turned again to the study of the annealing temperature effect onKesterite materials but this time in those of very low-cost materials and environmentally friendly Cu2ZnSnS4. We studied the growth of quaternary Cu2ZnSnS4 (CZTS) kesterite thin films by a single step electrochemical deposition followed by annealing at low temperature. The influence of different annealing atmospheres at constant annealing times (t = 45 min) and fixed preparation controlling parameters; i.e., starting materials (precursor metal salts) solution concentration, time of deposition and electrodeposition potential. Structural, compositional, morphological, and optical properties, as well as photoelectrochemical properties were studied.
Resum (Valencià) L'augment del consum d'energia global juntament amb les preocupacions ambientals ha generat molt d'interès per les fonts d'energia alternatives i netes, com ara l'energia solar fotovoltaica. Els investigadors de la comunitat fotovoltaica han estat buscant formes de reduir costos mentre mantenen o augmenten les eficiències. Una millor comprensió dels materials implicats és essencial per al ràpid desenvolupament de noves tecnologies. Les pel·lícules primes I-III-VI2 ofereixen sistemes prometedors per aconseguir cèl·lules solars d'alta eficiència a un cost menor. De fet, en adaptar la composició dels compostos, és possible canviar la banda prohibida del material per captar la llum solar de manera més eficient. Aquesta tesi se centra en la preparació i caracterització del material de la capa absorbent, especialment les pel·lícules primes nanocristal·lines i la consideració de les característiques estructurals i elèctriques d'aquesta capa principal absorbent de cèl·lules. La tesi examina com les diferents tècniques de preparació i ús del material podrien afectar les propietats del pel·lícules primes sintetitzades. Pel·lícules primes CuInSe2 i CuInS2 es van dipositar sobre substrats de vidre ITO usant la tècnica d'electrodeposició en solució aquosa. Les pel·lícules electrodepositadas es van caracteritzar per difracció de raigs X (XRD), microscòpia electrònica de rastreig (SEM) i anàlisi de raigs X d'energia dispersiva (EDS). Es van investigar els efectes de recuit sobre els precursors electrodepositados. L'estructura de calcopirita de CuInSe2/CuInS2 va mostrar una millora de la cristal·linitat després del tractament posterior de selenització/sulfurització en atmosfera de Se o S, respectivament. Els estudis de XRD i SEM van revelar una millora de la qualitat cristal·lina de les pel·lícules de CIS després dels tractaments tèrmics. Les propietats òptiques de les pel·lícules primes recuites CuInSe2-Es i CuInSe2-S s'han estudiat per determinar l'efecte del procés de recuit en diferents ambients de seleni i sofre. A més, modifiquem el CuInxCryGa1-x-ySe2 de coure indi, on x = 0.4, i = (0.0, 0.1, 0.2, 0.3) la capa d'superstrat pel procés de recobriment per centrifugat. CuInxCryGa1-x-ySe2 on x = 0.4, i = (0.0, 0.1, 0.2, 0.3) nanopartícules han estat sintetitzades en primer lloc fent servir un mètode hidrotermal químic humit que es basa en un procés tèrmic sense buit sense cap procés de selenización addicional. Introduint diferents fonts de metall en un autoclau amb etilenamina com solvent, es van obtenir nanopartícules de CIGS a diferents temperatures en un rang de 190- 230 °C. Els resultats de la difracció de raigs X (XRD) van confirmar la formació d'una estructura de calcopirita CuInxCryGa1-x-ySe2 tetragonal. Finalment, es va estudiar l'efecte de la temperatura de recuit en els materials tipus kesterita (com el Cu2ZnSnS4) que són materials de molt baix cost i que no danyen el medi ambient. Vam estudiar el creixement de les pel·lícules primes quaternàries Cu2ZnSnS4 (CZTS) de kesterita mitjançant un dipòsit electroquímic d'un sol pas seguit d'un recuit a baixa temperatura. La influència de diferents atmosferes de recuit a temps de recuit constants (t = 45 min) i paràmetres de control de preparació fixos; és a dir, concentració de la solució de materials de partida (sals de metalls precursors), temps de deposició i potencial d'electrodeposició. Es van estudiar les propietats estructurals, de composició, morfològiques i òptiques, així com les propietats fotoelectroquímiques
Kamal Abdelhamied Saber, S. (2018). Synthesis and characterization of some nano-selenides and their applications in solar cells [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/107389
TESIS
10
Yong, Chaw Keong. "Ultrafast carrier dynamics in organic-inorganic semiconductor nanostructures." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:b2efdc6a-1531-4d3f-8af1-e3094747434c.
Abstract:
This thesis is concerned with the influence of nanoscale boundaries and interfaces upon the electronic processes that occur within the inorganic semiconductors. Inorganic semiconductor nanowires and their blends with semiconducting polymers have been investigated using state-of-the-art ultrafast optical techniques to provide information on the sub-picosecond to nanosecond photoexcitation dynamics in these systems. Chapters 1 and 2 introduce the theory and background behind the work and present a literature review of previous work utilising nanowires in hybrid organic photovoltaic devices, revealing the performances to date. The experimental methods used during the thesis are detailed in Chapter 3. Chapter 4 describes the crucial roles of surface passivation on the ultrafast dynamics of exciton formation in gallium arsenide (GaAs) nanowires. By passivating the surface states of nanowires, exciton formation via the bimolecular conversion of electron-hole plasma can observed over few hundred picoseconds, in-contrast to the fast carrier trapping in 10 ps observed in the uncoated nanowires. Chapter 5 presents a novel method to passivate the surface-states of GaAs nanowires using semiconducting polymer. The carrier lifetime in the nanowires can be strongly enhanced when the ionization potential of the overcoated semiconducting polymer is smaller than the work function of the nanowires and the surface native oxide layers of nanowires are removed. Finally, Chapter 6 shows that the carrier cooling in the type-II wurtzite-zincblend InP nanowires is reduced by order-of magnitude during the spatial charge-transfer across the type-II heterojunction. The works decribed in this thesis reveals the crucial role of surface-states and bulk defects on the carrier dynamics of semiconductor nanowires. In-addition, a novel approach to passivate the surface defect states of nanowires using semiconducting polymers was developed.
11
Blom, Ulrika. "Hållbara material : fossilbaserade material byts mot hållbar (biobaserad) textil." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-22059.
Abstract:
Textil- och klädtillverkning är en tungt miljöbelastande bransch. För att ändra på det och få textilindustrin i en riktning mot en hållbar utveckling behöver CO2-utsläpp avsevärt minskas, vattenförbrukningen drastiskt sjunka och risken för spridning av mikroplaster i naturen minimeras. De tre vanligaste textila fibrerna på marknaden, polyester, bomull och polyamid, orsakar stora utsläpp av CO2 och förbrukar enorma mängder vatten. Den här rapporten söker finna svar på vilka textila material som kan uppfylla kraven på hållbarhet och om det finns miljövänliga material med likvärdig slitstyrka som hos de tre största fiberslagen. Med hjälp av en litteraturstudie, ett klassificeringsverktyg och ett antal tester på fysiska prover har materialen ovan tillsammans med lyocell och PLA undersökts och studerats. Den ekologiska och den fysiska hållbarheten har jämförts och värderats. Resultatet av studierna ger inga entydiga svar på frågorna. PLA verkar lovande, men är omgiven av en osäkerhet. Under tiden studien har pågått finns inga tecken på försvagning av PLA-tyget, men kommer det hålla för hundra tvättar? Lyocell är miljömässigt hållbart och slitstarkt i teorin, men smulades tidigt sönder i nötningstestet. Lyocelltyget var gjort av tunt stapelfibergarn. Skulle det varit starkare om det varit tillverkat av filamentgarn? Återvunnen polyester kontra jungfrulig polyester ger ingen stor miljövinst. Däremot ger återvunnen polyamid och ekologisk bomull stora miljömässiga förtjänster. Lyocell, PLA, ekologisk bomull och återvunnen polyamid skulle kunna vara ekologiskt och fysiskt hållbara material.Textiles and apparel manufacturing is a heavily polluting industry. To change that and get the textile industry in the direction of sustainable development, following must be done. Emissions of CO2 need to be considerably reduced, water consumption must drastically decline and the risk of spreading microplastics in nature have to be minimized. The three most common textile fibres on the market, polyester, cotton and polyamide, causing large emissions of CO2 and consumes huge amounts of water. This report seeks to find the textile materials that can meet the requirements of sustainability and eco-friendly materials of equivalent strength as in the three largest fibers like above. With the help of a literature review, a classification tool and a number of tests on physical samples have the materials above along with lyocell and PLA been examined and studied. The ecological sustainability and physical durability has been compared and measured. The results of the studies provides no clear-cut answers to the questions. The PLA seems promising, but are surrounded by uncertainty. In the meantime, the study has been going on, there are no signs of weakening of PLA-fabric, but will it keep for one hundred washes? Lyocell is environmentally sustainable and durable in the theory, but got an early break in the abrasion test. The lyocell fabric were made of thin yarn of staple fibers. Would it have been stronger if it had been made of filament yarn? Recycled polyester versus virgin polyester gives no great environmental benefits. However, recycled polyamide and organic cotton get large environmental gains. Lyocell, PLA, organic cotton and recycled polyamide could be environmentally and physically durable materials.
12
Antunes, Sofia Alexandra Duarte. "Mota-Engil divestment opportunity report." Master's thesis, NSBE - UNL, 2010. http://hdl.handle.net/10362/10340.
Abstract:
A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and EconomicsThis report points out a brief description of a well-known group, whose activities are spread in 19 countries, from an internal as well as external view. Its main business areas are Engineering & Construction, Environment & Services as well as Transport Concessions. Furthermore, the market was also relevant to be analyzed to contextualize the company in its proper markets and industries with its competitors in order to find opportunities of development or divestments to be made for the improvement of the company, to create value for its shareholders, adding value for the company as a whole.
13
Bergstrand, Therese. "Materialets betydelse i arbetet mot en jämställd förskola : Hur material används och hur könade genusroller görs i barns lekar." Thesis, Karlstads universitet, Institutionen för pedagogiska studier (from 2013), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-71156.
Abstract:
The purpose of the study is to describe how children use material and what gendered gender roles are done in children's games at preschool. This I have studied through four observations on a department in a selected space that I am calling for the building space. The earlier research is based on being a boy or girl. Therefore, with this study, I want to see which gender roles the children do in the preschool regardless of the biological gender. I have emanated from poststructural and posthuman perspective that is relevant to my purpose because it is consistent with how children are made gender roles and not already are. Since the material is a big part of the study, posthumanistic viewpoint gets an important part as the material is seen as an agent in children's subject creation. From theories I have found concepts that are used to understand the analysis of the results. The study shows that the material in preschool is largely gender neutral and that the children often create gender neutral roles. There are materials that are difficult available as evidence of gender material and the children often mention gender-like games like mom, dad, children but rarely take these roles in play. A role that returned in my study was "dog" which can be seen as a gender-neutral role. Keywords: Gender equality, gender roles, preschool, material, play.
14
Johansson, Rasmus. "Arbetsförmedlingens användaranpassning : En studie kring materialet riktat mot ungdomar." Thesis, Linköping University, Department of Social and Welfare Studies, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-57369.
Abstract:
Att anpassa sitt material efter olika målgruppers tilltänkta behov och förförståelse syftar till att bättre nå ut med information till gruppen ifråga. Detta riskerar dock att alienera de inom målgruppen som identifierar sig med den bild av målgruppen som anpassningen riktar sig mot. Anpassningen kan också resultera i att informationen blir bristande.
15
Fjellström, Daniel. "Mot en museologisk värdeteori : Varför vi ger och varför vi samlar." Thesis, Uppsala universitet, Institutionen för ABM, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-152633.
Abstract:
The foundation for a museum is the collection. To collect, preserve and display is what constitutes a museum. But the process of deciding which object´s should be saved, and which objects should not, are based on values. It is also values that make people inclined to donate objects to museums. How and why we value a museum determine if and why we donate. Objects themselves could be said to have a biography just like people. Depending on the objects biography and the context, the value of the object differs. My aim is to try and give an explanation to how we value the material heritage we collect, and to explain why people want to donate to museums; despite the fact they don’t get paid. I will also try and explain how value theory is used in economics and in philosophy, and how those value theories might differ from a museological theory of value.
16
Schade, Melody Marchman. "Paratextual frames| A material study of Ottaviano Petrucci's four-voice Venetian motet prints, 1502-1505." Thesis, State University of New York at Buffalo, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3629842.
Abstract:
This dissertation constitutes a material study of the four-voice motet prints published in Venice by Ottaviano Petrucci between 1502 and 1505. These prints, Motetti A, Motetti de passione de cruce de sacramento de beata virgine et huiusmodi, Motetti C and Motetti Libro Quarto, coincided with a burgeoning silent reading culture that was interested in and attuned to devotional reading—particularly as it was made available through books of hours (horae)—and thus, represented a new opportunity for early sixteenth-century singers, readers, and collectors. This dissertation considers how the relationship between motet print, reader and horae might have encouraged a devotional attitude from readers and singers of these volumes.
Chapter 1 considers horae, late medieval reading practice, and the intertwined relationship between reading and prayer. Many of the material aspects of the prints—especially size and mise-en-page ("page layout")—are similar to those of contemporaneous books of hours (horae) and their likeness might have encouraged a reading posture that resonated with devotional reading. Additionally, pictorial evidence is presented that suggests that by the mid-sixteenth century at least one family may have considered printed music in this manner.
Chapter 2 takes the page as a formal starting point and, building upon the work of Gérard Genette and Bonnie Mak, extends the discussion of materiality to considerations of paratexts. Here, a nuanced reading of the mise-en-page, which considers the page layout, typeface, musical font, and table of contents (tavolae), reveals a web of intellectual and devotional associations available to a contemporary reader of Petrucci's four-voice Venetian motet prints.
Chapter 3 explores the relationship between the page and the music-making that the page enabled and considers these through a study of a uniquely musical paratext—the fermata. Analytic apparatus advanced by both Robert Hatten and Bonnie Blackburn reveals that the concept of markedness as it relates to the visual, oral, and aural aspects of the page allows for all the elements of the page to coalesce in a manner uniquely familiar and meaningful to the devotionally attuned reader/singer of Petrucci's prints.
In analyzing the material and paratextual features of Petrucci's motet prints, this dissertation engages with an array of theoretical, analytical, and historical frameworks. It simultaneously positions Petrucci's prints within a multivalent world of reading, printing, publishing, and singing and ultimately situates the prints within the realm of devotional activities.
17
Saverstam, Maria, and Daniel Jonsson. "Laborativ matematikundervisning : Ett steg mot ett mer lustfyllt lärande." Thesis, Umeå University, Mathematics and Mathematical Statistics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-809.
Abstract:
Syftet med detta examensarbete är att undersöka det laborativa arbetssättet i skolan utifrån ett lärarperspektiv. När och hur kan man använda laborativa material för att förbättra matematikundervisningen? Vi har försökt att besvara dessa frågor med hjälp av lärarintervjuer. Resultatet visar att lärarna i studien anser att fördelar med laborativ undervisning framförallt innebär att det blir konkret för eleverna och det öppnar möjligheter att koppla den abstrakta matematiken i läromedlet till elevernas förkunskaper i matematik. De menar vidare att laborationer är lustfyllt och att detta i sin tur kan leda till att eleverna blir mer motiverade till matematik. Nackdelar med arbetssättet verkar i första hand handla om ramfaktorer. Ett laborativt arbetssätt kräver resurser i form av tid, utrymme, material och personal, vilket kan vara svårt att frambringa på vissa skolor. Lärarna i vår undersökning verkar trots detta väldigt positivt inställda till att använda ett laborativt arbetssätt som ett komplement till den traditionella undervisningen utifrån läromedel.
18
Arata, Laura Joanne. "Embers of the social city business, consumption, and material culture in Virginia City, Montana, 1863 - 1945 /." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Spring2009/l_arata_052909.pdf.
19
Minx, Sascha. "Optimering av monteringsavdelningen förfjädergunglekar : Med Lean mot kundorderstyrd montering." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-25670.
Abstract:
If Sweden want to be able to compete internationally with its production capacity,it is important to work actively with production development and production ofresource-and time-efficient. This report is a bachelor thesis of 15 hp conducted atthe University of Halmstad. Using the principles of continuous improvement andLean Production, the author developed a concept for HAGS Aneby AB to changeto the customer order driven assembly of spring toys.First of all, the theories of Lean Production, logistics and ergonomics are used tobuild and present a theoretical framework for further examination. Then, toachieve the target, the current assembly process is analyzed to develop some firstconceptual ideas for improvement. In order to develop the best advice, theconcepts are evaluated against the company’s requirementsThe developed action plan gives recommendations on how the company shouldrestructure their assembly process and the organization of the related departmentin order to produce spring toys in a more time efficient and lean way. The resultsshow the extent of economic improvements as well as the amount of time savingsthat can be realized through the improved assembly process. The concept could bepartially implemented in the company and there is an optimistic view of HAGSAneby AB to achieve more efficiency in their assembly process in the future.
20
Jansson, Jonathan. "Materialoptimering av Kranbom och Framtagning av Provstav : Ett undersökande arbete mot högcykelutmattning av kallformade ståldetaljer." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-80049.
Abstract:
Utmattning av stålmaterial är ett fenomen som varit känt i närmare 190 år men trots det är det fortfarande långt ifrån helt utforskat. Utmattningsegenskaper hos grundmaterial och svetsar är idag relativt utforskat, medan områden som utmattningsegenskaper hos kallformade stålprofiler fortfarande mer eller mindre är outforskat. Med utforskningen av utmattningsegenskaper hos kallformade stålprofiler som huvudsyfte delades examensarbetet upp i två delar. En överliggande kranbomsoptimering med huvudmålet att sänka vikten så mycket som möjligt med hjälp av materialbyte till ett mer höghållfast stål och optimal användning av material med avseende på utmattning. Den andra delen av examensarbetet är en framtagning av en provkropp med huvudmålet att kunna testa utmattningsegenskaper för kallformade stålprofiler samt att ge dimensionerande värden till kranbomsoptimeringen. Provstavsframtagningen resulterade i tre versioner av provkroppar som i teorin ska ge utmattningsegenskaper i longitudinell riktning för kallformade stålprofiler. Eftersom provstavarna inte kunde prövas på grund av tidsbrist baserades kranbomsoptimeringen på teoretiska värden. Resultatet av kranbomsoptimeringen var att vikten kunde sänkas från 1027 kg till 435 kg utan att påverka andra beaktade kranegenskaper.Even though fatigue in steel structures is a phenomenon that was discovered almost 190 years ago it is still far from fully explored. The fatigue properties of base materials and welded materials are currently relatively well known, but the fatigue properties of cold-formed steel profiles are still more or less unknown. With the investigation of fatigue properties of cold-formed steel profiles as the main purpose, this master thesis was divided into two parts. An overhead optimization of a crane with the main goal of reducing weight as much as possible with the help of upgrading materials to higher strength steels and using the materials in an optimal way with respect to fatigue. The second part of the master thesis is the development of a test specimen with the main goal of testing the fatigue properties of cold-formed steel profiles and to provide dimensioning values for the optimization of the crane. The development of test specimen resulted in three versions of specimens which in theory will provide fatigue properties in the longitudinal direction for cold-formed steel profiles. Since the test specimens could not be tested because of shortage of time, the optimization of the crane had to be based on theoretical values. The results of the optimization were that the weight could be lowered from 1027 kg to 435 kg without affecting any other consideration characteristics of the crane.
21
Diaz, Candido Jr. "Moth Catching Masters: Analysis Of The Structrual And Mechanical Properties Of The Silk Spun By The Derived Orb-Web Weaver Cyrtarachne akirai." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1524054250656993.
22
Almeida, Paulo Vitor Gomes. "Investigação dos saberes psicológicos presentes em material produzido entre 1870 e 1930, na Faculdade de Direito de São Paulo, e suas relações com o Direito Natural vigentes à época." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/59/59137/tde-23102013-135525/.
Abstract:
Os elos entre Direito e Psicologia são antigos, embora sua estruturação em moldes científicos tenha se dado apenas a partir do século XIX, na interface dos estudos dos saberes psicológicos com as doutrinas da lei criminal. Desse liame pontual, a conexão interdisciplinar se desenvolveu em vários outros ramos, sendo hoje vasto o campo de pesquisa. O presente trabalho visa abordar as relações entre os saberes psicológicos suscitados em material produzido na Faculdade de Direito de São Paulo no período crítico do nascimento da psicologia científica no Brasil e sua relação com os conceitos de Direito Natural vigentes à época. A escolha do Direito Natural, é em virtude deste ser mais adequado à análise psicológica, interessando ao estudo o embasamento filosófico/psicológico do Direito e não as leis em específico. O período estudado coincide com a Primeira República no Brasil. Neste momento há alterações significantes no contexto educacional, onde várias reformas promovem a transição do ensino clássico para uma matriz pragmático-científica; e no contexto dos saberes psicológicos, tendo em vista que a psicologia filosófica está em momento de transição de pensamentos da escola sensualista francesa, do empirismo e do ecletismo espiritualista para uma tradição positivista. No contexto jurídico se apresenta a Constituição de 1891, promulgada pela constituinte após breve governo de exceção dos militares, sendo este um período de instabilidade político-jurídica. Foram encontradas como objeto três teses. Duas são de José de Alcântara de Machado D\'Oliveira, sendo estas \"A embriaguez e a responsabilidade civil\" e \"Ensaio Médico-Legal sobre o hypnotismo\" e a outra de Candido Motta, denominada \"Classificação dos criminosos\". Os métodos utilizados na análise dos dados foram a Historiografia da Psicologia Científica e a análise conceitual dos documentos através do método da História Cultural. Os dados atuais permitem dizer que há apropriação dos principais conceitos de filosofia positivista da época, inclusive a eugenia spenceriana/lombrosiana no caso de Candido Motta, cuja tese visa ser uma manual de consulta na classificação do criminoso. Jose D\'Oliveira busca lançar nova luz sobre um problema recorrente da época e relevante ainda hoje - a embriaguez e a responsabilidade civil - e sobre o hipnotismo, com um viés igualmente científico-positivista. As concepções de Direito Natural se apresentam em momento de transição entre uma visão majoritariamente tomista, em que o Direito Natural está em conexão com o divino, para uma concepção antropológico-científica, onde este deriva da vivência dos povos. É possível discutir, com base nos dados coletados e analisados, que há consonância entre as concepções de Direito Natural e os saberes psicológicos utilizados pelos autores. Predomina a transição para modelos positivistas, visando incorporar as descobertas das ciências naturais. Os modelos baseados em concepções mais humanísticas, religiosas e filosóficas, segundo o positivismo de Comte, estariam no estado \'metafísico\' da humanidade, sendo necessária adoção das teorias condizentes com o terceiro e último estado, o \'científico\'. As concepções que eram predominantemente metafísicas começam a se estruturar como organicistas neste momento, antes de se configurarem como psicologizantes em momento posterior. Apoio financeiro/Bolsa: FAPESPThe links between Legal knowledge and Psychology are ancient, albeit it\'s structuration in scientific molds only having begun in the nineteenth century, in the junction of psychological knowledge and criminal Law doctrines. From this knot, interdisciplinary connections have developed in many branches, leaving a fertile research field. The current work intends to stretch out to the relations existent between psychological knowledge raised in material produced in Faculdade de Direito de São Paulo in the critical period of scientific psychology\'s birth in Brazil and it\'s relation with the concepts of natural Law of the period. The choice for natural law has to do with it being more prone to psychological analysis, being the interest of this study the philosohical and psychological basis of Law, not specific legislation. The time period in question matches the one of the First Republic of Brazil. In this moment there are significant alterations in the educational context, where several measures promote transition from classical teaching to a pragmatic-scientific matrix; and in the contexto of psychological knowledge, having in sight that phylosophical psychology is in a moment of transition from french sensualism, empirism and spiritualist eccleticism to a positivist tradition. In the legal context, 1891\'s Constitution is presented to the people after a brief period of military government, making it a period of political and legal instability. Three theses were found as objects of the research. Two of them from José de Alcântara de Machado D\'Oliveira, being those \"A embriaguez e a responsabilidade civil\" e \"Ensaio Médico-Legal sobre o hypnotismo\" and the other from Candido Motta, named\"Classificação dos criminosos\". The methods utilized in the analysis were Historiography of Scientific Psychology and concetual analysis of the documents through the method of Cultural History. Data shows that there is appropriation of the main concepts of the time\'s positivism philosophy, including spencerian/lombrosian eugenics in the case of Candido Motta, whose theses aims to be a consulting manual on criminal classification. Jose D\'Oliveira sheds new light on a recurring issue of the time period and na important issue still today - drunkness and civil resposibilty - and on hypnotism, with na equally positivist approach. The concepts of Natural Law are presented in a moment of transition between a majorly thomistic view, in wich Natural Law is in connection with the divine, to a anthropological-scientifical view, where Natural Law is derived from humans themselves, liviing in groups. It is possible to discuss, based on the data collected and analysed, that there is consonance between the notions of Natural Law and Psychological Knowledge used by the authors. The transition to positivistic models is predominant, aiming to incorporate natural science\'s discoveries. The models based on humanistic, religious and phylosophical conceptions, according to Comte, would be in a \'metaphysical\' stage of humanity, thus being necessary the adoption of theories that were congruent with Comte\'s third and last stage, the \'scientific\' one. Predominantly metaphysical views started to be structured as organicist in this moment, before a properly psychological framework in a further moment. Financial Support: FAPESP
23
Bacchi, Michael. "Dinamica ed equazioni del moto di stringhe classiche relativistiche." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18390/.
Abstract:
Studiando l'azione della stringa non relativistica e del punto materiale relativistico, vengono introdotte le condizioni al contorno di Dirichlet e di Neumann, il concetto di invarianza per riparametrizzazione e tutti gli strumenti matematici necessari per studiare le stringhe classiche relativistiche. In particolare si ricava l'azione di Nambu-Goto, le condizioni di Virasoro ed infine le equazioni del moto con la relativa soluzione. L'ultimo capitolo è dedicato allo studio delle correnti conservate dal moto della stringa.
24
Rose-Steel, Tamsyn. "French Ars nova motets and their manuscripts : citational play and material context." Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3313.
Abstract:
The discussion of citation and allusion has become an important area of research in Medieval Studies. The application of postmodern intertextual theories has brought scholars to a deeper understanding of the reuse of borrowed material, shedding new light on a culture of music and literature that was once dismissed as dully repetitive. This thesis builds on this work by examining in depth the manner in which citation and allusion was deployed in the fourteenth-century motet. Motets are a particularly fertile ground for discussion of the reuse of material, drawing as they do on a range of citational techniques such as borrowed liturgical tenors, modelling of rhyme schemes on existing works, and quotation of refrains and authorities. The polyphonic and polytextual nature of the motet enabled composers to juxtapose different registers, languages and genres, and thus to create an array of competing possible interpretations. This study is situated against several strands of recent scholarship. It draws on critical theory, as well as discussions of refrain definition, memory, manuscript compilation, and notions of voice, authority and authorship. Each chapter examines a particular body of work: the interpolated Roman de Fauvel, the works of Guillaume de Machaut, the motets of the Ivrea and Chantilly manuscripts, and finally those of Manuscript Torino J.II.9. In each case, looking at the use of citation and allusion connects to other concerns. In the Roman de Fauvel, citation in the motets can be seen as functioning alongside use of the vernacular, manuscript layout and illuminations to elucidate the narrative. In the works of Guillaume de Machaut citation is linked to his ambiguous self-presentation and authorial presence, and connects individual pieces in his complete works’ manuscripts. The Ivrea and Chantilly motets, while not linked by the same strength of context, demonstrate continuing use of thirteenth-century tradition. In this case, studying compilation choices may help us to understand how scribes interpreted citational material. Finally, I argue that understanding the internal use of symmetry in MS J.II.9 and its motets, and the reuse of material between the motets and the chansons of that repertory, vindicates the view that the music and poetry was composed by a single author well versed in mainstream tradition. I have been able to propose some previously unnoted allusions in the major works, and draw out the benefits of a holistic approach to understanding these motet and manuscripts. All this points to motets both continuing the writing traditions of the thirteenth century throughout the fourteenth and early fifteenth centuries, but also shows individual writers and compilers choosing to cite in a creative and innovative manner.
25
Pech, David. "Etude du comportement anticorrosion de revetements amorphes base Si élaborés par dépot chimique en phase vapeur." Phd thesis, INSA de Lyon, 2006. http://tel.archives-ouvertes.fr/tel-00120312.
Abstract:
Ce travail porte sur l'étude du comportement protecteur vis-à-vis de la corrosion de revêtements amorphes base Si élaborés par dépôt chimique en phase vapeur.Le caractère protecteur de revêtements de type SiOx et SiOxNy a été analysé sur différents types de substrats. La tenue à la corrosion résulte de la faible porosité et de la nature très isolante de ces couches.
La protection fournie par des dépôts SiCx et SiCxNy utilisés comme couche d'accrochage au DLC (“Diamond Like Carbon”) a ensuite été étudiée. L'influence du taux d'incorporation d'azote de films SiCxNy a révélé une corrélation entre la structure chimique, déterminée par XPS, et le caractère semi-conducteur de la couche, établi par Mott-Schottky. La tenue à la corrosion a été directement associée à la densité de porteurs de charge.
L'étude a été complétée par une caractérisation électrochimique et une approche tribocorrosion du caractère protecteur fourni par des revêtements duplex SiCxNy / DLC.
26
Rispoli, Hugo. "L'antagonisme dialectique matérialisme / idéalisme : un holisme polymorphe." Thesis, Montpellier 3, 2015. http://www.theses.fr/2015MON30035.
Abstract:
Le 19ème siècle connaît un renouveau des façons de penser proches du matérialisme. Celles-ci deviennent triomphantes avec Marx, Nietzsche .... Il s'agit d'analyser les causes de ce renouveau et ses conséquences sur les idéologies du 20ème siècle. Ces idéologies misent en œuvre sont prises dans une dualité matérialiste/idéaliste au sein de leurs différentes composantes. A la sortie du second conflit mondial et surtout après la chute des pays socialistes de l'Europe de l'est, cette dualité se recompose en s'adaptant à un champ politique unique et hégémonique. Le capitalisme entretient un rapport très paradoxal au matérialisme dans le même temps il l'appelle de ses vœux car il lui permet de détruire un obstacle : le christianisme social, mais il le dénature également en lui donnant une forme vulgaire d'un matérialisme de possession. Il ne peut pas lui redonner ses lettres de noblesse puisqu'il générerait un retour du politique (le marxisme,...). Or il se présente comme post politique et non idéologique. Dans le discours réemployant la rhétorique marxiste de fin de l'histoire prononcé par Francis Fukuyama, le capitalisme se présente de fait comme un Léviathan face à ce qui a réduit l'homme à l'état de nature : les idéologies « totalitaires ». Il permet également une remontée forte de l'idéalisme dans une dissonance perpétuelle entre morale et pratique. Le matérialisme étant vulgarisé et réduit, il ne porte plus en lui d'éthique et il devient limité à une pulsion d'achat. Le capitalisme, dans son appareil idéologique et sa culture de masse, apparaît comme double perpétuel au réelA journey inside history, ideology and psychology with a key, the antagonism between materialism and idealism. A new point of view arise and create a new kind of analysis on our modern times. From Martin Luther to today, we explore differents systems : Nazism, Socialism and Capitalism. We will find, in each system and so in human mind, this heuristic antagonism
27
Körner, Maria. "Det sensomotoriska materialet; ett hjälpmedel i matematikundervisningen : En undersökning gjord på en svensk montessoriskola mot de yngre åren." Thesis, Linköpings universitet, Institutionen för beteendevetenskap och lärande, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-65902.
Abstract:
Syftet med denna undersökning var undersöka det sensomotoriska materialets roll i matematikundervisningen i montessoriskolor, dels utifrån lärares upplevelser, dels utifrån elevers deltagande i undervisningen. Metoden som användes för undersökningen var fem kvalitativa intervjuer och tolv deltagande observationer. Undersökningen kopplas till Montessoris teorier och sensomotorisk inlärning. Slutresultatet visar att det karaktäristiska för det sensomotoriska materialet är färgkodning, isolering och felkontroll. Det sensomotoriska materialet har betydelse för lärandet eftersom materialet synliggör matematikens abstraktioner, vilket bidrar till att barns självtillit och attityder till matematik förbättras. Färgkodat material bygger på färgassociationer som klargör företeelser och gör att barnen kommer ihåg men kan även försvåra lärandet. När barnen får arbeta med flera sinnen förstärks lärandet, sinnesintrycken från materialet organiseras till en inre mental ordning. Barnen utvecklar sin motorik, självkänsla och stimuleras till nyfikenhet. Montessoris pedagogiska grundtankar gällande arbetsätt och materialets användning är att hålla i en grundläggande lektion eller trestegslektion. I den grundläggande lektionen går pedagogen igenom materialet med barnen och lämnar sedan barnet att utforska materialet själv. Trestegslektionen består av tre steg där barnet får namnge föremål, träna och bli förhörd tillsammans med pedagogen. Ett muskelminne skapas när barnen arbetar taktilt. Barnens perceptionsförmåga (varseblivning) påverkas av hur pedagogen framför lärandet. Pedagogens roll är att inte servera svaret utan låta barnen få tänka själva. Syftet är att barnen ska utveckla självständighet. Undervisningen är individanpassad där barnen får arbeta i sin egen takt.
28
Nyberg, James Ronald. "Learning Resource Center Characteristics of the 25 Most Profitable U.S. Industrial Corporations: Implications for Business and Higher Education." Thesis, University of North Texas, 1996. https://digital.library.unt.edu/ark:/67531/metadc279038/.
Abstract:
This study is a descriptive analysis of corporate learning resource centers. The study was designed to incorporate historical background and current status, organization and personnel, types and amount of alternate delivery instruction, and selected cost considerations in the establishment and maintenance of a learning resource center. A functional definition was furnished, with a deliberative attempt to encompass related synonyms. Discussion included training types or instructional delivery medium distinctions. A contribution of this study was the development, field testing, and enhancement of a survey instrument, which reflects the steps to be followed by those planning implementation of any learning resource center. Findings of this study indicated that learning resource centers were young and transitioning to increased on-line individualized and self-paced learning. Training and learning will become much less interdependent. Training types will increasingly become nontraditional and technology driven. Courseware will be received and managed remotely. Partnerships and cooperative efforts are mandates for business and higher education. Learner mobility will become normative, not the exception. Internet training will rapidly increase, most quickly among small business. Learning resource centers will continue to become more cost effective. This study proposed the redefinition of both learner and educator roles within a changing learning resource center environment. It was suggested that the learner role must become more active and that the corporate educator role, as a result of technology, will increase in passivity, tending toward that of facilitation. Implications and recommendations were specifically noted for both business and higher education. Specified nomenclature of "learner centers" or clearly "learner centered" has been advocated, reflecting the continuing evolution of the learning resource center. Technology, instructional media, mobility, availability and sharing of resources, less formalization, life-long learning, fiscal issues, Internet access, information and knowledge explosion, and downsizing, all combine to provide the view and demarcation of the new "learner centers."
29
Andersen, Camilla Eline. "Mot en mindre profesjonalitet : "Rase", tidlig barndom og Deleuzeoguattariske blivelser." Doctoral thesis, Stockholms universitet, Barn- och ungdomsvetenskapliga institutionen, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-114124.
Abstract:
This thesis deals with professionalism in early childhood education in relation to «race» and whiteness in primarily a Norwegian landscape. The overall aim of the study is to investigate how sociomaterial «race»-events can be understood as constitutive of preschool teachers’ subjectivity. The thesis is a theoretical experimentation with strong ties to a real social landscape. One of the main problems that the study evolves around is how «race» is silenced in the dominant discourse contributing to how preschool teachers can create socially just and indiscriminating pedagogical practices in a current «multicultural society». Hence, there seem to be a lack of tools for preschool teachers to think through how «race» might be part of their pedagogical practice in preschools, and how «race» is an important issue to address when working with how to perform pedagogy ethically and politically. More specifically and in a philosophical-theoretical manner, the study explores «white» preschool teachers’ relation to «race». The philosophical-theoretical-methodological conceptual toolbox for the study is mainly constructed from the philosophical work of Gilles Deleuze and Félix Guattari (1977, 1987). E.g. machinic assemblage, stratification, Body without Organs, nomadic subject, affect, individuation, micropolitics, becoming, actual/virtual and event. The methodological approach is highly inspired by decolonizing-, feminist poststructural- and critical methodologies. However, immersed with Deleuze and Guattaris philosophy of desire, what started out as a poststructural autoethnography transformed into a cartography of «my own» racial becomings in/with an early childhood landscape. The study shows how subjectivity, when understood as produced through sociomaterial «race»-events, offers another understanding of doing professionalism. Further, it offers an alternative understanding of how to create more socially just pedagogical practices in early childhood education.
30
Junior, Oswaldo Gonçalves. "Iniciativa privada na educação pública: a Fiat e o Programa Moto Perpétuo." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/48/48134/tde-07112007-114334/.
Abstract:
Este trabalho tem como meta confrontar estudos teóricos sobre a problemática das ações sociais de empresas com os resultados de um estudo de caso sobre o Programa Moto Perpétuo da Fiat Automóveis S.A. que, durante cinco anos (1997 a 2001), voltou-se à doação de kits de materiais paradidáticos para milhares de escolas de diferentes regiões do Brasil. Apesar do amplo alcance do Programa, base na qual seus promotores se apoiaram para afirmar tratar-se da maior parceria da iniciativa privada com o governo federal dentro do Acorda Brasil! Está na hora da Escola - programa do Ministério da Educação dedicado a estimular a participação da iniciativa privada através de ações em prol da educação -, não havia, até o momento, nenhum estudo que demonstrasse os efeitos práticos dessa ação, seja na melhoria da educação (propósito declarado como motivação principal para sua existência), seja nas implicações de um redimensionamento das esferas pública e privada, assunto que acalora muitos debates na atualidade. Diante dessas constatações, optou-se pela realização de levantamento e leitura de diferentes fontes que tratam, de maneira direta ou não, da chamada responsabilidade social de empresas. Além de passo fundamental para uma adequada abordagem do objeto estudado, em última instância, esta etapa possibilitou subsidiar inferências mais amplas sobre este tema que condensa interesses conflitantes, na maioria das vezes expressos por discursos de promoção e de crítica mais afeitos às ideologias que espelhados no significado concreto de muitas dessas ações sociais. Numa outra parte, mediante informações obtidas com a realização de entrevistas e pelo levantamento e exame de diversos documentos, se analisou o Programa Moto Perpétuo. Como um exemplo da atuação privada junto ao setor público, pôde-se verificar que as correntes expectativas da eficiência de gestão e transferência de recursos em quantidade e qualidade suficientes não se concretizaram. Não obstante, os números sobre o Programa que foram divulgados (alunos e escolas beneficiadas e montante de recursos investidos), comparativamente altos diante de outras iniciativas deste tipo, foram componentes do êxito na construção de uma imagem positiva por parte dos promotores dessa ação junto a setores da opinião pública. Na somatória dessas constatações e de outros aspectos analisados, foi possível demonstrar que prevaleceram interesses de ordem comercial em detrimento das motivações declaradas da iniciativa de ajuda à educação. Apesar de não se poder afirmar que a iniciativa tenha resultado num avanço privado redefinidor do caráter público dos sistemas estadual e municipal de ensino atingidos pelo Programa, há indícios de que a implementação do Moto Perpétuo esteve condicionada pelas relações público (governo federal) - privado (empresa do setor automobilístico), representando um inédito capítulo centrado na educação, frente a um panorama no qual sobressaem historicamente acordos de ajuda mútua de caráter político-econômico.The aim of this research is to confront theoretical studies about the problematic of social actions promoted by private companies with the results of a case study focusing the Moto Perpétuo Program sponsored by Fiat automobiles S.A. which, for five years (1997 a 2001), donated kits of educational materials to thousands of schools from different regions of Brazil. Despite the ample reach of the Program, in which its promoters based themselves to assert that it was the biggest partnership of a private institution with the Brazilian Federal Government Program of Education Acorda Brasil! Está na hora da escola (Wake up Brazil! It´s time of school) destined to encourage private institutions to act for the education there wasn t, up to now, any study that could demonstrate the practical effects of this action, whether it was for the educational improvement (declared purpose as the main motivation for its existence), or in the implications to reassess the extent of the public and private spheres, a question that heats many debates nowadays. In the face of these observations, it was opted to do a reading and research from different sources that deal, directly or not, with the business social responsibility. More than a fundamental step for an appropriated approach of the studied object, this stage permitted to subsidise broader inferences about this subject, which condenses conflicting interests, frequently expressed by speeches of promotion and criticism more accustomed to ideologies than mirrored in the concrete meaning of many of these social actions. In another part, the Moto Perpétuo Program was analysed by the information obtained from interviews and researches. As an example of the private acting in the public sector, it was verified that the current expectations of management efficiency and transfer of resources, in quantity and quality, didn t come true. Nevertheless, the data published about the Program (resources invested, students and schools benefited) comparatively high in the face of other initiatives like that, were components of success in the construction of a positive image made by the promoters of this action for the public opinion. In the sum of these observations and other aspects analysed, it was possible to demonstrate that commercial interests prevailed over the declared motivations to assist the education. Although it was not possible to assert that the initiative has resulted in a private advancement redefining the public nature of the State and Municipal system of teaching reached by the Program, there are evidences that the implementation of the Moto Perpétuo was conditioned by the relationship between the public (Federal Government) and the private (automobiles company), representing an unheard-of chapter centred on the education, facing a survey that stands out agreements of mutual help of political-economical nature.
31
Hultman, Martin. "Full gas mot en (o)hållbar framtid : Förväntningar på bränsleceller och vätgas 1978 - 2005 i relation till svensk energi- och miljöpolitik." Doctoral thesis, Linköpings universitet, Tema teknik och social förändring, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-60061.
Abstract:
I föreliggande avhandling undersöker Hultman hur bränsleceller och vätgas underolika tidpunkter beskrivits som delar i ett framtida energisystem 1978 – 2005. Detempiriska materialet som analyseras är statliga utredningar, böcker, rapporter,tidningsartiklar och riksdagstryck. Syftet är att undersöka vilka aktörer sombeskrev tekniken, på vilket sätt tekniken konstruerades samt hur dessa förflyttadesoch förändrades under olika tidsperioder. Avhandlingens empiri undersökstillsammans med teorier om utopier och förväntningar på teknik samt tidigareforskning om svensk energi- och miljöpolitik. Avhandlingen är indelad i kronologiskt strukturerade kapitel vilka länkas sammanav analytiska platåer. I slutkapitlet diskuteras resultaten av den historiskaförändringen från visionerna om vätgassamhällen till en vätgasekonomi i treteman. Inom det första temat analyseras omdaningar över tid med fokus påaktörer, argument och teknik. I det andra temat fokuseras hur föreställningar omtekniken byggdes upp till nya höjder mellan 2000-2005. Bland annat diskuterashur tekniska, ekonomiska, miljörelaterade och säkerhetsmässiga förväntningarskapades med hjälp av starka metaforer som vatten, vägkartan och marknaden.Dessa förväntningar gjordes på olika platser och lånades mellan lokaliteter. I dettredje temat diskuteras vätgasekonomin som en ekologiskt modern utopi. I ensådan extrapoleras framtiden utifrån en ökning i takten av teknikförändringarna,men samtidigt ska samhällsstrukturerna konserveras.At the turn of the millennium, high expectations were connected to a technologycalled fuel cells. It was said that it could contribute in a significant way to solvingthe problem of increasing greenhouse gas concentrations in the atmosphere andreverse the greenhouse effect. But this was not the first time fuel cells andhydrogen has been described as a technology for the future and connected todifferent kind of utopias. On the contrary, this technology has a history ofexpectations connected to it and in this dissertation the period 1978 – 2005 isanalysed with focus on reoccurring arguments, main actors and how descriptionsof expectations move between different locations and different periods of time.These questions are answered with an analysis of empirical material that containsgovernmental reports, mass media articles, scientific reports as well as field notesfrom an participatory study. In this dissertation the analysis is read together withprevious research regarding Swedish energy- and environmental politics as wellas international research about fuel cell and hydrogen. The investigation is alsoinformed by theories about utopia and sociology of expectations. The main conclusion to be drawn from the historical period 1978 – 2005 is thatthe utopia hydrogen and fuel cells are said to be parts of change, from differentpossible hydrogen societies to one hydrogen economy. This change can beexemplified with changing roles of science, technology and the state as well ashow former environmental activists and political parties change their values.
32
Aeschlimann, Raphaël. "Magnetic and transport properties of rare-earth titanate thin films and heterostructures." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS142.
Abstract:
Les oxydes de métaux de transitions possèdent une large gamme de fonctionnalités (supraconductivité, magnétisme, ferroélectricité, multiferroicité) découlant de l’interaction d’effets structuraux et de corrélations fortes. De plus, des travaux récents ont mis en lumière une physique propre à leurs interfaces, incluant de la supraconductivité ainsi que de la conductivité classique dans le système bidimensionnel (2DES) créé à l’interface de deux isolants de bande, LaAlO₃ et SrTiO₃. Malgré cela pour couvrir l’immense potentiel des interfaces d’oxydes et leur phases électroniques sans précédent, il est nécessaire de combiner des oxydes plus fortement corrélés. Cette thèse à la croisée des chemins entre la physique des électrons fortement corrélés, du magnétisme et de la spintronique a pour but de combiner les instabilités magnétique et électronique pour créer de nouvelles phases électronique contrôlable par stimulus externe. Pour cela nous nous sommes intéressés à la famille relativement inexplorée des titanates de terres rares dont l’ordre magnétique ferro ou antiferro est contrôlé par la taille de la terre rare. Contrairement aux travaux existants, nous nous somme concentrés sur les membres ferrimagnétiques de la famille et leur intégration dans des 2DES. Cette thèse se développera autour de deux axes principaux. Dans un premier temps nous avons étudié plusieurs membres de la famille des titanates de terres rares sous la forme de couches minces épitaxiées. Nous avons aussi mis en évidence la présence d’une couche morte magnétiquement active à la surface de ces échantillons et expliqué sa présence par une suroxydation des ions titane de la surface. Nous avons aussi étudié la présence inattendue d’un moment orbital porté par le titane dans certains des composés étudiés et l’avons corrélé à leur structure magnétique non-colinéaire en conjonction avec un gradient structural observé en microscopie électronique en transmission. Dans un second temps nous avons combiné DyTiO₃ avec SrTiO₃ pour obtenir une interface conductrice possédant des propriétés de magnetrotransport complexes que nous avons interprété avec l’aide d’un modèle faisant intervenir le couplage spin-orbite ainsi qu’un magnétisme induitTransition metal oxides possess a broad range of functionalities (superconductivity, magnetism, ferroelectricity, multiferroicity) stemming from the interplay between structural effects and electronic correlations. Recent work has revealed exciting physics at their interfaces, including conductivity and superconductivity in the two-dimensional electron system (2DES) that forms at the interface between two band insulators, LaAlO₃ and SrTiO₃. However, to embrace the immense potential of oxide interfaces and unveil unprecedented electronic phases, combining insulators with stronger electronic correlations is necessary. At the crossroad between strongly correlated electron physics, magnetism and spintronics, the present thesis project aims to harness electronic and magnetic instabilities in correlated oxides to craft new electronic phases controllable by external stimuli. We investigated rareearth titanates RTiO₃, a relatively unexplored family of Mott insulating perovskites with a crossover between antiferromagnetic and ferromagnetic orders upon changing the rare-earth size. Contrary to most previous works, we focused on ferromagnetic compounds, and their integration in 2DES. The thesis developed along two main axes. First, we explored several members of the rare-earth titanates family in epitaxial thin film form. We highlighted the presence of a magnetically active dead layer at the surface of thin films and established its origin as due to the overoxidation of titanium ions. We also studied the presence of an unexpected orbital moment carried by the titanium in some compounds, and discussed it in the light of the non-collinear spin arrangement promoted by the rare-earth orbital moment and of a structural gradient evidenced by transmission electron microscopy. In a second stage, we combined DyTiO₃ with SrTiO₃ to stabilize a conducting interface with puzzling magnetotransport properties that we interpreted with a model involving spin-orbit coupling as well as induced magnetism
33
Rupp, Jonathan Amadeus Johannes [Verfasser], Rainer [Akademischer Betreuer] Waser, and Max Christian [Akademischer Betreuer] Lemme. "Synthesis and resistive switching mechanisms of mott insulators based on undoped and Cr-doped vanadium oxide thin films : as function of nanostructure and material properties / Jonathan Amadeus Rupp ; Rainer Waser, Max Christian Lemme." Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1218019719/34.
34
Ström, Kristina. "Livscykelanalysen som metod mot ökad miljöhänsyn och hushållning av energi och material : En fallstudie med utvärdering av verktyg anpassade för LCA på byggnader." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-88700.
Abstract:
The method of analyzing environmental impacts and resource use from a lifecycle perspective is growing in popularity as a method giving the opportunity to lessen negative impact on the environment and depletion of natural resources through comparative analysis. The report focuses on comparing tools available for lifecycle analysis of buildings and building materials as well as the method of LCA in general. A field study is made through analyzing a building with the aid of LCA and according to ISO 14040, and this brings further clarity as to how the method is used. The results show advantages and disadvantages of current LCA tools for buildings as well as pros and cons of the method of LCA itself. The results of the field study indicate the risk that LCA can be used and interpreted subjectively as well as the risk of setting too low data quality. Results also highlight the absence of some important features linked to environmental concern and sustainable resource management. However, if LCA is used in an objective and scientific manner it might be a key to using proper resource management in terms of lessening negative impacts on the environment and depletion of natural resources and some suggstions are made as to how to change the standards of the method.
35
D'AMICO, MICHELE EUGENIO. "Soil ecology and pedogenesis on ophiolitic materials in the western Alps (Mont Avic Natural Park, North-western Italy): soil properties and their relationships with substrate, vegetation and biological activity." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2009. http://hdl.handle.net/10281/10401.
Abstract:
Soils formed from ultramafic rocks are normally by pH values close to neutrality, a high base status and are usually rich in Mg, Fe and heavy metals. The low Ca/Mg ratio and the high heavy metal content could cause toxic effects in the biological communities. Plant communities, in particular, are usually different from nearby areas with different substrates and rich in endemisms and adapted species and subspecies.
Despite their great environmental and ecological interest, pedological and ecological properties of mountain or boreal soils developed on similar substrates have seldom been studied worldwide. 198 soil pits (associated with phytosociological surveys) have been opened and analyzed in the ophiolitic area of Mont Avic Natural Park (Val d’Aosta, Western Alps, Italy), beween 900 and 2900 m above see level. Soils formed from ultramafic, mafic rocks and calcschists have been observed, in order to recognize the most ecologically important soil factors.
The results show that soil properties are related with altitude and slope aspect in forest habitats, while the effect of substrate becomes important above timberline. Strong leaching in forest soils, related to high acidity and to the podzolization process, decrease the total and bioavailable heavy metal contents, above the treeline pedogenic and geomorphic processes release and accumulate large quantities of potentially hazardous trace elements. The plant communities strictly depend on the edaphic properties above the treeline, while in the forest habitats the differences caused by substrate are less discernible.
Microbial and microarthropodal communities suffer stress caused by heavy metals in forest soils, while at the alpine level non significant statistical or ecological correlation are visible.
Heavy metals (Ni, in particular) are the most important edaphic properties in differentiating plant communities on different substrata, while the Ca/Mg ratio (usually considered the most influencing soil properties on ultramafic soils) has no particular ecological effect.
36
Hägg, Marcus, and Henrik Sjölund. "Fuktvandring i putsade lättbetong- och tegelfasader : En undersökning om hur fukt vandrar och beter sig mot en putsfasad av två olika material med olika porositeter." Thesis, KTH, Byggteknik och design, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-126949.
Abstract:
I dagsläget finns en stor mängd byggnader i Sverige där fasaden består av puts direkt anliggande mot antingen lättbetong eller tegel. Dessa fasader kan skapa problem för brukaren p.g.a. fukttransport via putsen direkt in i konstruktionen. Problemen som kan uppstå som följd av dessa konstruktioner är inte bara estetiska utan kan även påverka inomhusmiljön. Syftet med detta arbete var att undersöka om det gick att med ny teknik visa de resultat som framkommit från erfarenheter från praktiskt arbete samt undersöka hur en renovering påverkar de fasader som består av puts direkt mot lättbetong eller tegel. Arbetet har utförts med hjälp av simuleringsprogrammet Wufi Pro för att sedan analyserats med hänsyn till fukttransporter och vatteninnehåll. Resultaten som framkommit påvisar en förhöjd risk för problem med de ursprungliga fasaderna samt slutsatsen att en renovering enligt ett av de två förslagen är att föredra.Today there’s a great deal of buildings in Sweden where the facade is constructed by plaster directly connected to either aerated concrete or masonry brick. These facades could create problems for the user on accord of the moisture transport via the plaster directly into the construction. The problems that could follow these types of facades aren’t just esthetical but could also affect the indoor environment. The purpose with this study was to examine if it would be possible using today’s technology to show the results coming from past experiences by practical work, and at the same time examine how a remodel affects the facades that consists of plaster directly on aerated concrete or masonry brick. The work has been conducted with the simulation program Wufi Pro, later to be analyzed according to moisture transport and water content. The results that came from this has shown an increased risk for problems with the original facades and at the same time that a remodel according to one of the two proposed remodel ways to prefer.
37
Coy, Diaz Horacio. "Preparation and Characterization of Van der Waals Heterostructures." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6212.
Abstract:
In this dissertation different van der Waals heterostructures such as graphene-MoS2 and MoTe2-MoS2 were prepared and characterized. In the first heterostructure, polycrystalline graphene was synthesized by chemical vapor deposition and transferred on top of MoS2 single crystal. In the second heterostructure, MoTe2 monolayers were deposited on MoS2 by molecular beam epitaxy.
Characterization of graphene-MoS2 heterostructures was conducted by spin and angle resolve spectroscopy which showed that the electronic structure of the bulk MoS2 and graphene in this van der Waals heterostructures is modified. For MoS2 underneath the graphene, a band structure renormalization and spin polarization are observed. The band structure of MoS2 is modified because the graphene induces screening which shifts the Г-point ~150 meV to lower binding compared to the sample without graphene. The spin polarization is explained by the dipole arising from band bending which breaks the symmetry at the MoS2 surface. For graphene, the band structure at lower binding energy shows that the Dirac cone remains intact with no significant doping. Instead, away from the Fermi level the formation of several gaps in the pi-band due to hybridization with states from the MoS2 is observed.
For the heterostructures made depositing monolayer of MoTe2 on MoS2, the morphology, structure and electronic structure were studied. Two dimensional growth is observed under tellurium rich growth conditions and a substrate temperature of 200 °C but formation of a complete monolayer was not achieved. The obtained MoTe2 monolayer shows a high density of the mirror-twins grain boundaries arranged in a pseudo periodic wagon wheel pattern with a periodicity of ~2.6 nm. These grain boundary are formed due to Te-deficiency during the growth. The defect states from these domain boundary pin the Fermi level in MoTe2 and thus determine the band alignment in the MoTe2-MoS2 heterostructures.
38
Rohloff, Martin [Verfasser], Anna [Akademischer Betreuer] Fischer, Arne [Gutachter] Thomas, and Anna [Gutachter] Fischer. "BiVO4-based photoanodes for photoelectrochemical water splitting : towards strategies to overcome major drawbacks of the most promising photoanode material / Martin Rohloff ; Gutachter: Arne Thomas, Anna Fischer ; Betreuer: Anna Fischer." Berlin : Technische Universität Berlin, 2018. http://d-nb.info/1164076418/34.
39
Paul, Anne. "Modélisation numérique des déformations d'un édifice volcanique : applications au Mont St Helens." Grenoble 1, 1986. http://www.theses.fr/1986GRE10006.
Abstract:
La mesure des déplacements de surface liés â l'activité volcanique est une méthode très utilisée dans la surveillance et l'étude des volcans actifs. De nombreux modèles mécaniques ont été réalisés pour tenter de déduire la structure interne de ces données de déplacements, et notamment pour localiser les chambres magmatiques. Mais ils négligent tous le caractère fortement hétérogène et discontinu des édifices volcaniques. Un nouveau modèle permettant précisément l'étude des milieux hétérogènes et fracturés est utilisé. Son hypothèse de base est que l'édifice se comporte comme s'il était constitué d'un assemblage de blocs se déplaçant les uns par rapport aux autres. L'éruption très bien documentée du Mont St Helens (1980) sert de test pour cette méthode de blocs, en permettant de comparer déplacements calculés et déplacements mesurés. Quatre modèles bi-dimensionnels de ce volcan sont construits à partir d'une coupe géologique nord-sud. Chacun d'eux permet de tester l'effet d'un paramètre du modèle (géométrie, conditions aux limites, coefficient de frottement entre blocs, chemin de sollicitation). L'intrusion d'un dôme de lave à l'intérieur du flanc nord est simulée par l'application d'une montée en pression incrémentale puis les modèles sont soumis à une accélération horizontale simulant un séisme. Les résultats de cette modélisation mettent en évidence la dépendance des modes de déformation et de rupture vis à vis du coefficient de frottement entre les blocs. On obtient un assez bon accord avec les observations pour la plus faible des deux valeurs de ce coefficient testées (O. S). La rupture du flanc nord en grand glissement de terrain se produit aussi bien sous la seule influence de la montée en pression que sous pression et séisme combinés. Mais le second type de chargement donne un meilleur accord des résultats avec la réalité, et confirme ainsi qu'un séisme était bien à l'origine de l'éruption. Enfin, on discute, à la lumière de ces résultats, de la possibilité d'appréhender les structures internes et les mouvements du magma, à partir des mesures de déplacements de surface
40
Moses, Kenneth C. "Biomimicry of the Hawk Moth, Manduca sexta (L.): Forewing and Thorax Emulation for Flapping-Wing Micro Aerial Vehicle Development." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case158687503705972.
41
Zerrad, Mehdi. "Caractérisation expérimentale et modélisation numérique du comportement vibratoire des matériaux polymères chargés en fibres courtes : Application à un carter d’huile de Groupe Moto-Propulseur thermique d’automobiles." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI064.
Abstract:
Les normes européennes d'émissions de CO2 étant de plus en plus contraignantes, les constructeurs automobiles cherchent, entre autres, à alléger leurs véhicules pour en diminuer la consommation. Ainsi, le remplacement des pièces métalliques par d'autres réalisées à partir de matériaux moins denses tels que les matériaux composites polymères chargés en fibres courtes est de plus en plus utilisé dans l'industrie automobile. Cependant, lors du processus de conception, les ingénieurs sont confrontés à des difficultés lors de la modélisation numérique de la réponse vibro-acoustique de ces pièces et/ou assemblages. En effet, ces matériaux sont très sensibles aux paramètres extérieurs tels que la température, la fréquence de sollicitation et l’humidité. De surcroît, leur comportement dépend également du procédé d’injection utilisé qui influe sur leur microstructure et plus particulièrement sur l’orientation et la dispersion des charges renforçantes. De fait, leur modélisation numérique est complexe et la confrontation aux mesures expérimentales non satisfaisante. Dans ce travail de recherche, l'influence des paramètres ambients sur le comportement dynamique d'un carter d'huile réalisé en polyamide 6 renforcé à 35\% en masse de fibres de verre a été étudiée. Les caractérisations mécaniques et microstructurales locales ont été effectuées afin d'investiguer les relations entre la microstructure et les propriétés de ces matériaux. Un modèle numérique a alors été développé sur la base de ces études expérimentales et a permis d’évaluer l'influence de la microstructure sur le comportement vibratoire d'un système modèle "plaque". Enfin, des corrélations calculs/essais ont été réalisées pour confronter la méthode de modélisation numérique aux mesures. Ces études ont permis de mettre en exergue la sensibilité de ces matériaux à leur environnement, d’établir une hiérarchisation de l'influence des différents paramètres sur leur comportement vibratoire et de proposer une méthodologie numérique basée sur la caractérisation expérimentale des éléments constitutifs pris séparémentAs European standards for CO2 emissions are becoming more stringent, car manufacturers are seeking, among other strategies, to lighten their vehicles to reduce their consumption. Thus, the replacement of metal parts by others made from lighter materials such as polymeric composite materials filled with short fibers is increasingly used in the automotive industry. However, during the design process, engineers face difficulties when trying to numerically model the vibro-acoustic response of these parts and / or assemblies. Indeed, these materials are very sensitive to external parameters such as temperature, loading frequency and humidity. In addition, their behavior also depends on the injection process which has an influence on their local microstructure and more particularly on the orientation and dispersion of the reinforcing fillers. In turn, their numerical modeling is complex and the comparison with the experimental measurements unsatisfactory. In this research work, the influence of the ambient parameters on the dynamic behavior of an oil pan made of polyamide 6 reinforced with 35\% by mass of glass fibers was studied. Local mechanical and microstructural characterizations were performed to investigate the relationship between the microstructure and the properties of these composite materials. A numerical model was then developed on the basis of these experimental studies and allowed to evaluate the influence of the microstructure on the vibratory behavior of a model plate system. Finally, computation / test correlations were performed to compare the numerical modeling method to the measurements. These studies have made it possible to highlight the sensitivity of these materials to their environment, to establish a hierarchy of the influence of the various parameters on their vibration behavior and to propose a "low cost" numerical methodology based on the experimental characterization of constituent elements taken separately
42
Teggi, Gloria. "Il problema dei due corpi." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/12108/.
43
Gutekvist, Olsson Cecilia, and Fanny Norkko. "Omvänd logistik - vägen mot hållbar utveckling? : Hur ökad återanvändning av byggmaterial i samverkan kan bidra till en mer cirkulär ekonomi på byggarbetsplatser." Thesis, KTH, Fastigheter och byggande, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264396.
Abstract:
Under de senaste årtiondena har planeten, på grund av människans överanvändning av resurser, genomgått stora klimatförändringar och global uppvärmning. Den prognostiserade ökningen av population i kombination med den urbanisering som pågått de senaste 40 åren där fler söker sig till storstäderna kommer att resultera i ett ökat bostadsbyggande. Detta i sig innebär stora utmaningar då byggsektorn idag står för en betydande del av samhällets klimatpåverkan ur ett livscykelperspektiv. En del av byggsektorns negativa klimatpåverkan kommer från dess ohållbara avfallshantering där en stor mängd av det avfall som slängs är potentiellt återanvändbart material. Med anledning av detta har syftet med denna studie varit att undersöka huruvida omvänd logistik, inriktat mot återbruk, i samverkan mellan byggentreprenörer i begränsade tätbebyggda stadsområden kan reducera avfall av byggmaterial för en mer hållbar utveckling. Det teoretiska ramverk som identifierats i studien, och ligger till grund för resultatet och de slutsatser som dragits, består främst av tre teorier: hållbar utveckling, cirkulär ekonomi och omvänd logistik. Hållbar utveckling med sina tre underdimensioner: social, ekologisk och ekonomisk hållbarhet syftar huvudsakligen till det optimala läge där jordens resurser förbrukas på ett så hållbart sätt som möjligt. Cirkulär ekonomi är en process där ett använt material används så länge som möjligt i ett cirkulärt kretslopp med möjligheten att organisera och optimera hållbara materialflöden genom att bevara resurser och minska avfall. Slutligen är omvänd logistik en gren inom logistiken som syftar till hur en produkt av något slag hanteras, efter att den sålts och använts, med en effektiv hantering som antingen skapar nytt värde eller korrekt bortskaffande. Empirin är framtagen utifrån en kvalitativ metod i form av intervjuer kompletterat med kvantitativa data från en enkät. Resultatet bekräftar det som utgör studiens problem att det slängs brukbart material varpå ett medelvärde på åtta procent av det totala avfallet enligt studien har uppskattats vara brukbart. De materialen med störst potential till återanvändning är virke, skivmaterial av olika slag, isolering, armering och stålreglar. Gällande studiens inriktning att öka återanvändandet i samverkan mellan byggentreprenörer så finns det en generellt positiv inställning till det. Det finns även en insikt i att det genom samverkan kan vara möjligt att lösa problemet med dagens ohållbara avfallshantering under förutsättningen att de utmaningar som identifierats kan lösas. De största utmaningar som identifierats i studien var främst problematik med lagerhållning, kvalitetssäkring av återanvändningsbart material och resursineffektivitet. I studien har det framkommit att för att kunna påbörja återanvändning i samverkan för alla typer av byggmaterial finns det faktorer som måste lösas vilket innebär att det inte är något som kan implementeras idag. Däremot finns det inga egentliga större hinder till att börja återanvända standardiserat byggmaterial till provisorier då kvalitetsäkringsfrågan i form av garanti inte är relevant samt att det finns ett behov av sådant material under hela byggprocessen vilket löser problematiken med lagerhållning. För att påbörja arbetet med detta skulle digitala plattformar som idag redan finns kunna användas som marknadsplats, där det läggs in en begräsning på vilka som får köpa materialet som då skulle vara närliggande projekt. Även en enkel utgångpunkt istället för en digital plattform vore att en tätare kommunikation hålls mellan projekten och att materialfrågan därmed kan hanteras på samverkansmöten som hålls en gång i veckan. Slutligen kan det utifrån detta konstateras att efter en tids implementering av den här typen av omvänd logistik, inriktat mot återanvändning i samverkan, bör mängden avfall kunna reduceras jämfört med idag. Det skapar en mer cirkulär ekonomi i de begränsade tätbebyggda stadsområdena vilket i sin tur bidrar till en mer hållbar utveckling.In the past decades the planet has, due to human overuse of resources, undergone climate change and global warming. Because of the projected increase of the population as well as the urbanization that has been going on the last 40 years, where more people seek towards metropolitan areas, it will result in an increased construction of housing. This will result in challenges considering the fact that the construction sector today represents a significant part of society's negative climate impact from a life-cycle perspective. One factor contributing to the negative climate effect given by the construction industry is its unsustainable waste management in which a significant part of the wasted materials is reusable. For this reason, the purpose of this research has been to investigate whether reverse logistics, targeted at reuse of construction materials, in collaboration between contractors in limited urban areas can reduce waste materials for sustainable development. The theoretical framework identified in this study, from which the result obtained originates and the conclusions are drawn, consists primarily of three theories: sustainable development, circular economy and reverse logistics. Sustainable development with its three dimensions: social, ecological and economic sustainability is aimed to reach the optimal stage in which resources are consumed in a sustainable way as possible. Circular economy is a process where used material is used as long as possible in a circular cycle with the ability to organize and optimize sustainable material flows, this by conserving resources and reducing waste. Lastly, reverse logistics is a branch within the common logistics that manage products of any kind after usage with an efficient management that either creates new value or a proper disposal. The results are based on a qualitative method with interviews supplemented by quantitative data from a questionnaire. The results confirm what constitutes the study's problem of today's unsustainable waste management in which still usable materials are discarded, whereupon the mean value of eight percent of the total waste is estimated to still be usable. The materials with the greatest potential for reuse are wood, board materials of various kinds, insulation, reinforcement bars and steel joists. Regarding the study's focus on increasing reuse in collaboration between contractors, a general positive attitude is seen towards it and there is an insight in the fact that solving the problem of today's unsustainable waste management will be difficult without collaboration. However, this is given by the fact that the challenges identified can be solved. The identified challenges in the study were mainly problems with quality assurance on reusable materials, inventory and resource inefficiency. In this study it has emerged that when it comes to starting reuse in collaboration consisting all types of building materials, there are factors that must be resolved before it will be possible. Something that stands in the way of implementing it today. On the other hand, there are no major obstacles towards reusing standardized building materials for temporary work since the quality assurance issue in the form of a guarantee is not relevant and that there is a need for such material during the entire building process, which solves the problem of inventory. To begin work on this, digital platforms that already exist today could be used as a marketplace, where a restriction is placed on who may buy the material. It could also be as simple as keeping a closer communication between projects. Finally it can be concluded that, after a period of time, an implementation of this type of reverse logistics, focused on reuse in collaboration, will be able to reduce the amount of waste compared to today. This will create a more circular economy in limited urban areas, whilst contributing to a more sustainable development.
44
Karlsson, Oscar, and Oskar Hjalmarsson. "Effektivare material-och produktionsstyrning för minskad genomloppstid i en process hos ett företag med funktionell layout : En fallstudie på Press Kogyo Sweden AB." Thesis, Linnéuniversitetet, Institutionen för ekonomistyrning och logistik (ELO), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-104538.
Abstract:
Bakgrund: Dagens marknader har med tiden tenderat att bli mer globala vilket i sin tur har ökat konkurrensen mellan företag. Detta har inneburit att många industriorganisationer har behövt förändra sig för att vara konkurrenskraftiga på marknaden. Ett koncept som idag genomsyrar många företag är lean vilket bygger på att maximera användandet av sina resurser, eliminera slöserier och skapa en effektivare tillverkning. Genom att arbeta med lean kan företag uppnå snabbare genomloppstider. Syfte: Syftet med studien är att kartlägga Press Kogyos propellerprocess för att kunna identifiera icke-värdeadderande aktiviteter i processen. Vidare kommer studien bidra Press Kogyo med förslag gällande hur en effektivare material- och produktionsstyrning kan reducera genomloppstiden i propellerprocessen. För att studien ska uppnå teoretisk relevans är ytterligare ett syfte med studien att bidra med teori kring hur tillverkande företag, med en funktionell layout, kan reducera de nackdelar som finns med layouten med effektivare material- och produktionsstyrning. Genomförande: Studien har delats upp i tre forskningsfrågor. De två första forskningsfrågorna var specifikt inriktade mot det studerade företaget medan den tredje forskningsfrågan var mer generellt ställd mot tillverkande företag med funktionell layout. Studien har genomförts som en fallstudie och präglats av kvalitativa forskningsmetoder. Empiriska data har samlats in genom intervjuer, observationer samt en fokusgrupp. För första forskningsfrågan skapades processkartor och VSM-kartor. Dessa i samband med diverse intervjuer låg till grund för att identifiera icke-värdeadderande aktiviteter/slöserier i propellerprocessen vilka påverkade genomloppstiden. För forskningsfråga två applicerades teori kring material-och För tillverkande industriföretag kan en reducering av genomloppstid generera diverse fördelar. Några av dessa fördelar är: minskat antal produkter i arbete, bättre kvalité, minskade kostnader, bättre prognoser, ökad flexibilitet samt minskad ledtid gentemot kund. Press Kogyo har under en längre period upplevt en problematik kring en av deras processer. Problematiken har legat i att de inte vetat om vilka icke- värdeadderade aktiviteter som finns i processen samt hur de påverkar genomloppstiden. produktionsstyrning i syfte att reducera de icke-värdeadderande aktiviteterna/slöserier som identifierats och följaktligen reducera genomloppstider i processen. Gällande forskningsfråga tre genomfördes intervjuer med det studerade företaget och ett annat tillverkande företag med funktionell layout. Författarna ämnade att genom dessa intervjuer besvara hur tillverkande företag med en funktionell layout kan reducera de nackdelar som finns med den layouten med hjälp av effektiv material- och produktionsstyrning. Slutsats: I studien identifierades sju slöserier där väntan ansågs vara det slöseri vilket mest påverkade genomloppstiden i propellerprocessen. För att eliminera alla slöserier och framförallt väntan applicerades teori kring material- och produktionsstyrning med fokus på production activity control (PAC). Den teori vilken användes skapade också en teoretisk modell vilken kan vara en bra grund när företag med funktionell layout vill effektivisera sin planering. Vissa delar av den teoretiska modellen användes också senare i studien där den användes för att reducera de nackdelar vilka kan finnas med en funktionell layout.Background: Today's markets have over time tended to become more global, which in turn has increased competition between companies. This has meant that many industry organizations have had to change in order to be competitive in the market. A concept that today permeates many companies is the lean practice, which is based on maximizing the use of resources, eliminating waste, and creating more efficient production. By working with lean, companies can achieve faster throughput time. For manufacturing industrial companies, a reduction in throughput time can generate various benefits. Some of these advantages are: reduced number of products in work, better quality, reduced costs, better forecasts, increased flexibility and reduced lead time towards customers.Press Kogyo has for a long period experienced problems with one of their processes. The main problem has been that they do not know what non-value-added activities/waste that can be found in the process and how these activitiesaffect the total throughput time of the process. Purpose: The purpose of the study is to map Press Kogyo's propeller process in order to be able to identify non-value-adding activities in the process. Furthermore, the study will provide Press Kogyo with proposals regarding how more efficient material and production control can reduce the throughput time in the propeller process. In order for the study to achieve theoretical relevance, another purpose of the study is to contribute with theories about how manufacturing companies, with a functional layout, can reduce the disadvantages of the layout with more efficient material and production control. Methodology: The study has been divided into three research questions. The first two research questions were specifically aimed at Press Kogyo, while the third research question was more generally directed at manufacturing companies with a functional layout. The study was conducted as a case study and was characterized by qualitative research methods. Empirical data has been collected through interviews, observations, and a focus group. For the first research question, process maps and VSM maps were created. This together with various interviews created the foundation for identifying non-value-adding activities/waste in the propeller process which affected the throughput time. For research question two, theory of material and production control was applied in order to reduce the non-value-adding activities/waste and consequently reduce throughput time in the process. Regarding research question three, interviews were conducted with Press Kogyo and another manufacturing company with a functional layout. The authors intended to, through these interviews, find answers to how manufacturing companies with a functional layout can reduce the disadvantages of the layout with the help of efficient material and production control. Conclusions: In the study, seven wastes were identified where “wait” was considered to be the waste that affected throughput time the most in the propeller process. To eliminate all waste and specifically the waste “wait”, methods and theories regarding material and production control was applied with a focus on production activity control (PAC). All the different theories that was used also created a theoretical model which can be a good basis for planning when companies with a functional layout want to find ways tostreamline their planning. Some parts of the theoretical model were also used later in the study where it was used to reduce the disadvantages that may exist with a functional layout
45
Andersson, Tommy. "Redesign av reduktionsutrustning i asselvalsverk inom stålindustri : Ett examensarbete utfört på konstruktionsbyrån BEKAB mot stålindustriföretaget Ovako." Thesis, Linköpings universitet, Maskinkonstruktion, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-108786.
Abstract:
Intresset för sömlösa stålrör med stora ytterdiametrar i förhållande till tunna väggtjocklekar har ökat tillsammans med att högre hållfasthet i olika stålsorter tillkommit. Detta gör det möjligt att tillverka lättare, billigare och mer materialeffektiva stålprodukter med samma eller högre hållfasthet som tidigare. Denna nya utvecklingsriktning medför förändringar och utmaningar i en av företaget Ovakos produktionslinor i Rörverk 5 Hofors, vilket de har behov av att samarbeta med maskinkonstruktionsföretaget BEKAB för att utvärdera och utveckla. I Ovakos produktionslina i Rörverk 5 finns en del av ett asselvalsverk som kallas för "förreducerare". Denna del av asselvalsverket ser Ovako ett stort intresse i att utvärdera och utveckla för att bättre anpassas till den nya utvecklingsriktningen. En känd utmaning hos förreduceraren sen tidigare är att den från början är framtagen för att reducera ner ett kvalitetsproblem hos rörprodukterna som kallas för trattbildning. Projektet fördjupar sig därför inom trattbildning för att bättre förstå grunden till förreducerarens nuvarande design för att därefter genomföra en redesign av förreduceraren. I en nulägesanalys av nuvarande förreducerare framkommer ett flertal olika produktionsutrustningsproblem med tillhörande kvalitetsproblem hos rörprodukterna. Projektet väljer därmed att fokusera på de produktionsutrustningsproblem som ger störst effekt för förreduceraren om de löstes. Detta resulterar i ett nytt produktkoncept av förreduceraren i form av en visuell 3D-CAD-modell med tillhörande hållfasthetsberäkningar och materialoptimering. Studien behandlar ämnen som design, konstruktion, produktutveckling, hållfasthet samt materialoptimering.The interest in seamless steel tubes with large outside diameters in relation to thin wall thickness has increased along with the strength improvements in various steel grades. This makes it possible to produce lighter, cheaper and more material-efficient steel products with the same or greater strength as before. These new development directions bring changes and challenges in one of the company Ovako's production lines in Tube Mill 5 Hofors, which they need to cooperate with the design agency BEKAB to evaluate and develop. In Ovako's production line in Tube Mill 5 there is a part of an assel mill called "förreducerare". Ovako sees a lot of interest in evaluating and developing this part of the assel mill in order to better adapt to the new development directions. A well-known challenge of the existing reduction equipment is that it was initially developed to reduce a quality issue with the tube products called funnel formation. The project therefore immerses itself into the funnel formation in order to better understand the foundations of the current design of the reduction equipment and to then implement a redesign of the reduction equipment. A situation analysis of the current reduction equipment reveals a number of different production issues with their accompanying quality issues in the tube products. The project thus chooses to focus on the production issues that would have the greatest impact on the reduction equipment if they were resolved. This results in a new product concept of the reduction equipment in the form of a visual 3D-CAD-model with associated strength calculations and material optimization. The study covers topics such as design, engineering, product development, material strength calculations and material optimization.
46
Bravenec, David. "Diagnostika a návrh eliminace tepelných mostů budov." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265536.
Abstract:
This thesis presents a comparison of building materials for vertical bearing structures of buildings, thermal insulation materials and mutual combination of structural materials and insulators. Furthermore, there are possibilities for solving the most common insulation thermal bridges construction. The paper evaluated the pros and cons of different combinations of building materials. Teplo and Area programs were used for the calculations.
47
Jacobsen, Jan Kindberg. "Greek pottery on the Timpone della Motta and in the Sibaritide from c. 780 to 620 BC reception, distribution and an evaluation of Greek pottery as a source material for the study of Greek influence before and after the founding of ancient Sybaris /." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2007. http://irs.ub.rug.nl/ppn/304182907.
48
Le, Losq Charles. "Rôle des éléments alcalins et de l'eau sur les propriétés et la structure des aluminosilicates fondus et vitreux : implications volcanologiques." Phd thesis, Université Paris-Diderot - Paris VII, 2012. http://tel.archives-ouvertes.fr/tel-00923471.
Abstract:
Au cours de cette thèse, nous avons étudié le rôle des éléments alcalins et de l'eau sur les propriétés et la structure des aluminosilicates vitreux et fondus. Ces compositions sont importantes pour les sciences de la Terre et pour l'industrie des verres, vitrocéramiques et céramiques. La viscosité de ces compositions alcalines fondues a été mesurée, et leurs structures à courte et moyenne distances ont été étudiées dans les verres à l'aide des spectroscopies Raman et RMN. Les résultats obtenus montrent que la viscosité des aluminosilicates fondus est fortement dépendante de l'élément alcalin M présent dans le réseau, du rapport M/Al et du rapport Si/Al. La structure du réseau vitreux change en fonction du cation M. Plus son rayon ionique est élevé, plus il distord le réseau, et plus la viscosité augmente. Les tectosilicates de potassium vitreux sont ainsi composés de zones enrichies en silice, et de zones enrichies en aluminium et en potassium. Le potassium pourrait être présent dans des chenaux dans ces compositions. Les ions potassium et sodium, ayant des coordinences différentes, ne se mélangent pas aléatoirement dans les tectosilicates vitreux et fondus, induisant de fortes variations de leurs propriétés rhéologiques. Nous avons mis en place un protocole, basé sur la spectroscopie Raman, permettant de mesurer la concentration et la spéciation de l'eau dissoute dans un aluminosilicate vitreux ou fondu, quelque soit sa composition chimique. Ce protocole permet d'observer les liaisons entre l'eau et le réseau silicaté, et les résultats obtenus confirment le caractère amphotérique de l'eau dissoute dans les aluminosilicates vitreux et fondus. En combinaison avec la mise en place de modèles ad hoc de viscosité des magmas et avec l'utilisation de résultats apportées par la géochimie et la géologie, l'application de cette technique à l'étude de ponces volcaniques permet d'apporter des informations quant aux mécanismes intervenant lors des éruptions volcaniques. Cette approche globale nous a permis de mieux caractériser les processus de fragmentation ayant eu lieu lors des éruptions de 3.1 Ma du Mont Dore (France) et de 79 AD du Vésuve (Italie), ainsi que le processus de convection du magma de l'Erebus (Antarctique).
49
Guillemot, François. "Couches poreuses de silice structurées par des latex : structure, propriétés mécaniques et applications optiques." Phd thesis, Ecole Polytechnique X, 2010. http://pastel.archives-ouvertes.fr/pastel-00543809.
Abstract:
Les couches minces à bas indice de réfraction présentent un intérêt important pour ajuster les propriétés optiques de certains dispositifs, par exemple leur réflectivité. Les couches sol-gel mésoporeuses de silice préparées par auto-assemblage de tensioactif ont été l'objet de nombreuses études mais présentent un indice de réfraction très peu stable puisqu'elles peuvent être le lieu de condensation capillaire d'eau atmosphérique. Pour dépasser ce problème, nous avons préparé des couches sol-gel poreuses de silice, structurées par des latex synthétisés spécifiquement, avec des tailles de pores supérieures à 30 nm, pour lesquelles la condensation capillaire n'a pas lieu. Ces couches ne présentent pas de microporosité dans les murs de silice, ce qui permet d'ajuster indépendamment et précisément la taille des pores, leur fraction volumique ainsi que leur chimie de surface. L'accessibilité des pores en fonction de leur taille et de la fraction poreuse a été étudiée par ellipsométrie-porosimétrie et par annihilation de positons. Une transition de percolation entre une porosité ouverte et fermée a été observée lorsque l'on fait décroître la fraction poreuse. Les propriétés mécaniques des couches ont été étudiées par nanoindentation : nous avons montré que module d'Young et dureté suivent un modèle de surface solide minimale. Le caractère modèle des propriétés structurales et mécaniques des couches ainsi préparées nous permet d'envisager une optimisation des propriétés du matériau. Ces couches poreuses avec un indice de réfraction très stable et ajustable sur une large gamme (de 1,10 à 1,45) sont ainsi très prometteuses pour des applications optiques
50
Eriksson, Andreas, and Gabriel Ågren. "Materialtester på KL-trä : Undersökning av KL-träets tryckkraftskapacitet och tryckhållfasthet samt teoretiska beräkningar och praktiska tester av en KL-trä bräda." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-85125.
Abstract:
Belastningen vid tryck vinkelrätt mot fiberriktningen är ett problem vid höga träbyggnader med träregelstomme vid till exempel mötet mellan regel och syll. Ettmaterial som blivit alltmer populärt i Sverige är korslimmat trä, som benämns som KL-trä, där lameller korsvis limmas samman till en skiva. Experiment har tidigare utförts på materialet och det har visat att en bräda av KL-trä, som idag inte tillverkas, klarar ett högre stämpeltryck än en vanlig bräda av konstruktionsvirke, vilket skulle kunna vara en lösning på problemen vid tryck vinkelrätt fiberriktningen i höga träbyggnader. Syftet med detta examensarbete är att bestämma KL-träets karakteristiska tryckkraftskapacitet och tryckhållfasthet för två uppställningar av KL-trä där andelar vinkelräta och parallella lameller som belastas i tvärsnittet skiljer sig åt. Det undersöks också hur lasten fördelar sig på lamellerna som belastas parallellt med fiberriktningen och vinkelrätt mot fiberriktningen i en bräda av KL-trä samt att teoretiska beräkningar av tryckkraftskapaciteten utfördes i mitten och i änden på brädan. Examensarbetet omfattades av tre olika metoder där standarden SS-EN 408 för tryck vinkelrätt mot fiberriktningen användes för att bestämma tryckkraftskapacitet och tryckhållfasthet för de två uppställningarna av KL-trä genom materialtester i en hydraulisk press. Lastfördelningen mellan lamellerna i en KL-trä bräda undersöktes genom stämpeltrycktester i änden på brädan och återspeglar ett verkligt möte mellan regel och syll. En solid bräda av KL-trä, en bräda där de vinkelräta lamellerna sågats bort samt en bräda av konstruktionsvirke belastades för att undersöka differensen i stämpeltryck. Teoretiska beräkningar utfördes på KL-trä brädorna både i mitten och i änden genom att de olika lamellerna beräknades som enskilda brädor enligt Eurokod 5 samt EKS11 och därefter summerades alla lameller för KL-trä brädan. Resultaten visade att den uppställningen av KL-trä med störst andel lameller som belastades parallellt med fiberriktningen erhöll störst tryckkraftskapacitet och fick högst tryckhållfasthet. I brädan av KL-trä tog de lameller som belastades parallellt med fiberriktningen upp ungefär fyra femtedelar av lasten i tvärsnittet som belastades. De teoretiska beräkningarna som utfördes gav en lägre tryckkraftskapacitet än resultaten från de experimentella testerna. För materialtest 1 där lamellerna fördelade sig 58 % vinkelräta lameller och 42 % parallella lameller erhölls karakteristiska värden på 79,7 kN på tryckkraftskapacitet och 18,6 MPa på tryckhållfasthet. För materialtest 2 där lamellerna fördelade sig 42 % vinkelräta lameller och 58 % parallella lameller erhölls karakteristiska värden på 114,6 kN på tryckkraftskapacitet och 26,8 MPa på tryckhållfasthet. Belastningsfördelningen i KL-trä brädan visade att de parallellt belastade lamellerna tog upp en last motsvarande 80,8 % och de vinkelräta lamellerna tog upp en last motsvarande 19,2 %. De teoretiska beräkningarna utnyttjades till 57 % i jämförelse mot maxlasten från de experimentella testerna, både i mitten och på brädans ände.Compression perpendicular to the grain is today a problem with tall wood buildings with timber-frame at, for example, the meeting between timber stud and the bottom rail. A material that has become increasingly popular in Sweden is cross-laminated timber, which is referred to as CLT, where lamellae are glued together crosswise to a board. Experiments have previously been performed on the material and it has shownthat a board made of CLT, which is not manufactured today, can withstand a higher pressure than an ordinary board made of structural timber, which could be a solution to the problems with compression perpendicular to the grain in tall wood buildings. The purpose of this thesis is to determine the CLTs characteristic compressive force capacity and compressive strength for two formations of CLT where proportions of perpendicular and parallel lamellae that are loaded in the cross section differ. It will also be investigated how loads are distributed on the lamellae which are loaded parallel to the grain and perpendicular to the grain in a board made of CLT and that theoretical calculations of the compressive force capacity were performed in the middle and at the end of the board. The thesis was comprised of three different methods where the standard SS-EN 408 for compression perpendicular to the grain was used to determine compressive forcecapacity and compressive strength for the two formations of CLT through material tests in a hydraulic press. The load distribution between the lamellae in a CLT-boardwas examined by compression tests at the end of the board and reflects a real meeting between a timber stud and the bottom rail. A solid board made of CLT, a board where the perpendicular lamellae were sawn off and a board made of structural timber were loaded to investigate the difference in compression. Theoretical calculations were performed on the CLT-boards both in the middle and at the end through calculating the different lamellae as individual boards according to Eurocode 5 and EKS11 and then all lamellae for the CLT-board were summed. The results showed that the arrangement of CLT with the largest proportion of lamellae parallel to the grain obtained the largest compressive force capacity and had the highest compressive strength. In the CLT-board, the parallel-loaded lamellae took up about four-fifths of the load in the cross-section that was loaded. The theoretical calculations performed gave a lower compressive force capacity than the results of the experimental tests. For material test 1 where the lamellae were distributed 58% perpendicular lamellaeand 42% parallel lamellae, characteristic values of 79.7 kN on compressive capacity and 18.6 MPa on compressive strength were obtained. For material test 2 where the lamellae were distributed 42% perpendicular lamellae and 58% parallel lamellae, characteristic values of 114.6 kN on compressive capacity and 26.8 MPa on compressive strength were obtained. The load distribution in the CLT-plank shown that the parallel-loaded lamellae took up a load corresponding to 80.8% and the perpendicular lamellae took up a load corresponding to 19.2%. The theoretical calculations were used to 57% in comparison with the maximum load from the experimental test, both in the middle and at the end of the board.