Les oxydes de métaux de transition sont largement utilisés en raison de leurs propriétés fondamentales intéressantes et de leurs applications importantes. En particulier, CuCrO2 est d’un intérêt particulier parce qu’il possède un état multiferroïque en absence de champ magnétique. Dans cette thèse, nous modélisons les propriétés magnéto-électriques de CuCrO2 par simulations Monte Carlo basées sur des paramètres magnétiques déterminés par calculs ab initio. Nous étudions également l’effet du dopage du Ga sur les propriétés magnéto-électriques du composé CuCr1-xGaxO2 (0 ≤ x ≤ 0:3). Nos résultats sontqualitativement en accord avec les observations expérimentales. / Transition metal oxides are widely used due to their interesting fundamental properties and important applications. In particular, CuCrO2 is of special interest because it enters the multiferroic state in zero magnetic fields. In this thesis we model the magnetoelectric properties of CuCrO2 using Monte Carlo simulations with the help of ab initio calculations.We also investigate the effect of Ga doping on the magnetoelectric properties of CuCr1-xGaxO2 (0 ≤ x ≤ 0:3). Our results are well comparable to the experimental observations.

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La fonction principale des systèmes d'ancrage des éoliennes offshore flottantes est de limiter les mouvements du support. Les lignes d'ancrage qui les composent sont typiquement constituées de chaînes, de câbles aciers, de câbles synthétiques ou d'une combinaison de ces composants.Dans cette thèse, on se concentre sur les câbles en acier qui permettent de réduire le poids et d'augmenter la résistance en tension par rapport aux chaînes. Leur dimensionnement dépend des chargements en tension et flexion, liés aux mouvements du flotteur sous l'action de la mer et du vent.L'objectif de la thèse est le développement d'un nouveau modèle numérique pour prédire la durée de vie en fatigue des câbles d'ancrage d'une éolienne offshore flottante. Il doit notamment simuler les glissements relatifs entre les fils au cours d'une flexion du câble. Des résultats d'essais de tension-flexion de la littérature ont en effet montré que la première rupture est localisée près du plan neutre de flexion, où ces déplacements relatifs sont les plus grands. Cet effet majeur sur la durée de vie du câble n'est pas pris en compte par les lois de fatigue en tension-tension des normes de design offshore actuelles.Il faut aussi remarquer que l'utilisation d'un modèle détaillé de câble dans une démarche de dimensionnement à la fatigue représente un vrai défi. Le nombre élevé d'interactions de contact à modéliser, de l'ordre de plusieurs milliers par mètre de câble, et le grand nombre de cas de chargement rendent ce type de calculs très coûteux.Les chargements qui sont utilisés dans le modèle local de câble sont issus de calculs globaux réalisés à l'aide d'un logiciel multiphysique (Deeplines). Ce logiciel permet de simuler les conditions environnementales (vent, houle, courant) appliquées sur l'ensemble de la structure offshore.Nous montrons que le comportement non linéaire en flexion du câble, lié aux interactions de contact entre les fils, n'influence pas significativement les résultats du modèle global. Cette observation justifie une démarche de type descendante, les calculs globaux pouvant être réalisés en première étape. Les évolutions temporelles des tensions et courbures globales sont appliquées uniformément sur le fil central du modèle local du câble. La continuité du câble est représentée par des conditions de périodicité reliant les sections de bord à des points internes du modèle situés sur la même position circonférentielle. Les fils sont modélisés par des éléments poutres. On obtient les contraintes généralisées sur les fils, les forces de contact et les glissements relatifs. Des premières analyses ont montré que les déplacements relatifs entre les fils restent petits dans notre cadre d'application. Afin de réduire le coût calcul, nous avons développé un nouvel élément de contact entre poutres non parallèles, avec un appariement fixe de contact, dans l'hypothèse de petits glissements mais en grands déplacements et grandes rotations. Des tests numériques montrent l'amélioration obtenue, avec un résultat plus proche d'un modèle de référence qui considère un contact surfacique. De plus, le nouveau modèle réduit significativement le coût calcul et se montre plus robuste en convergence, ce qui s'avère crucial pour un calcul de fatigue. Les sorties du modèle local sont ensuite utilisées pour prédire un état de contrainte 3D, en exploitant des solutions analytiques de contact entre corps cylindriques. Finalement, un critère de fatigue multiaxial de la littérature est appliqué pour évaluer le risque en dommage. / The main function of mooring systems of floating offshore wind turbines is to ensure station keeping. The mooring lines can be composed of chains, wire ropes, synthetic ropes, or even a combination of them. In this thesis we focus on wire ropes, whose advantage over chain is to sustain high tension at a lower weight. Their design must consider the successive tension and bending loading induced by the floater movement for various wind and waves conditions.The thesis purpose is to develop a new numerical model, dedicated to the prediction of fatigue damage in mooring wire ropes of a floating wind turbine. In particular it has to simulate the relative movements between the wires when the rope is bent. Results from free-bending fatigue tests in the literature show the importance of these effects, since the first rupture is localized near the neutral plane, where fretting is more important. This phenomenon affecting the fatigue life is not considered by fatigue criteria of current offshore standards, which are related to tension-tension loading.It is worth noting that the use of a detailed model of wire rope in a fatigue design procedure represents a real challenge. The high number of contact interactions to be modeled, which are several thousands per meter of rope, and the large amount of loading cases make this type of computations extremely time-consuming.The loading used in the developed local model of wire rope is obtained from global computations performed with a dedicated multiphysics software (Deeplines). This software allows to simulate the environmental conditions (wind, waves, current) applied on the whole structural system.Some preliminary computations showed that the nonlinear bending behavior of the wire rope, linked to the wire contact interactions, does not significantly affect the output of the global model. This observation justifies the use of a top-down scheme, with a prior computation of the global scale.The global scale tension and curvature are then uniformly imposed on the central wire of the local model. The continuity of the rope is represented by periodic conditions which link the end sections to points within the model, at the same circumferential locations. The wires are modeled by beam elements. The outputs at the local scale are the stress resultants on the wires, and the contact forces and relative displacements at contact locations.Small sliding between the wires has been observed from first numerical analysis, for a representative loading case. Therefore, in order to reduce the computational cost of the wire rope model, a new node-to-node contact element has been developed, dedicated to the modeling of contact between non-parallel beams with circular cross section. It assumes fixed contact pairing and finite rotations. Numerical benchmarks and experimental tests on wire ropes show the improvement with results closer to a reference surface-to-surface model, when compared to standard algorithm for the simulation of contact between beams. Moreover, the new model reduces significantly the CPU cost and is also more robust, which is crucial for fatigue life estimates.The outputs of the local scale model are then used to obtain the complete 3D stress state by means of analytical solutions of contact between solids with cylindrical shape. Finally, a multiaxial fatigue criterion is applied in order to assess the safety of the system.

No description available.

No description available.

Syftet med den här studien var att undersöka en alternativ slamningsreducerande teknik till spolning, som effektivt kan ta bort biologisk påväxt. Ultraljud undersöktes som en möjlig metod för att ta bort igenslamningen från omvänd osmos med ett spirallindat membran. Tidigare forskning har föreslagit att ultraljud skulle kunna vara effektivt på platta membran men inte på spirallindade membran, på grund av packningsdensiteten som spirallindan medför. Därför genomfördes inom denna studie försök med spirallindade membran och ultraljud, för att få en förståelse av dess effekter inom det spirallindade membranet. För det första undersöktes tidsberoendet av ultraljud, vilket visade liknande resultat som tidigare forskning, att ultraljudet uppnådde effekt inom några minuter. För det andra behandlades två membran en gång om dagen under 12 dagar, med undantag för dag 6 och 7. Ett behandlades med ultraljud och ett med spolning, och den mikrobiologiska kontamineringen i permeatet analyserades sedan. Det ultraljudsbehandlade membranet producerade mindre kontaminering under de 12 dagarna. Det krävs dock fler experiment och analyser för att bekräfta detta, eftersom tidsbegränsningar inte möjliggjorde repetitioner. En ekonomisk utvärdering genomfördes också för att undersöka möjligheten att implementera ultraljud i kommersiell skala. Den ekonomiska aspekten är en avvägning mellan vattenkostnad och energikostnad, som är beroende av geografiskt läge. Överlag indikerar resultaten att det sparade vattnet kostar mer än den energi som krävs, vilket är fördelaktigt för implementering av ultraljudsbehandling. Sammanfattningsvis visade ultraljudsbehandlingen bättre resultat än spolning inom några minuter, och hade även en ekonomisk fördel, men kostnaden för energi till vatten är beroende av geografisk plats. / The purpose of this study was to investigate an alternative fouling mitigation technique to flushing, that can efficiently remove biological fouling. Ultrasound was investigated as a possible method of removing fouling from a reverse osmosis spiral wound membrane. Previous research had suggested ultrasound to be efficient on flat sheet membranes but not on spiral wound membranes, due to the packing density. Therefore, this study conducted experiments on spiral wound membranes with ultrasound, as to get an understanding of its effects within the spiral wound membrane. Firstly, the time dependency of ultrasound was investigated, and showed similar results to that of previous research, that the ultrasound was efficient within a matter of minutes. Secondly, two membranes were subject to treatment once a day over the span of 12 days, with an exception for days 6 and 7. One was treated with ultrasound and one with flushing, and the microbiological contamination in the permeate was then analysed. The ultrasonically treated membrane produced less contamination throughout the 12 days. However, more experiments and analysis would be required to confirm this, as time constraints did not allow for repetitions. An economic assessment was also performed, as to evaluate the feasibility implementing ultrasound on a commercial scale. This is a weigh-off between water cost and energy cost, which is dependent on geographical location. Overall, the results indicate that the water saved costs more than the energy required though, which is favourable for the implementation of ultrasonic treatment. To conclude, the ultrasonic treatment showed better results than flushing within a matter of minutes, and also economically had an advantage but the cost of energy to water is relative to geographical location.

Being innovative allows organizations to be part of the rapid competitive and environmental shifts and requires the development of knowledge as it builds the pathway of innovation. Since most companies find it troublesome to effectively utilize their existing knowledge towards innovations and literature lacks to offer solutions, this study aims to determine factors that contribute to an enhancement of the spiral of knowledge as well as to develop a concept that provides counselling for business and academia on how to overcome this issue. Therefore, this study contributes with new insights to the field of research in knowledge management and innovation management as well as to organizations with a concept on how to operationalize knowledge management towards innovation. Based on literature review on innovation management, knowledge management and organizational agility, a hypothesis was established that claimed that agile feedback loops at the spiral of knowledge would facilitate the utilization of knowledge management towards innovation. Expert interviews allowed the identification of factors that are relevant for tapping the potential of knowledge towards innovation. The analysis of their responses disclosed a common request to include feedback during the knowledge transformation but also revealed that design thinking and an innovative organizational culture are further relevant factors. Thus, the study postulates a concept that refines the spiral of knowledge to the ‘spiral of knowledge and innovation’, which extents the ‘spiral of knowledge’ with agile feedback loops, design thinking as well as an innovative organizational culture.

Syftet med denna studie har varit att granska den forskning som fanns beskriven i vetenskapliga artiklar omkring de problem som uppstår och de upplevelser som kvinnan får vid insättning av spiral. I en litteraturstudie valdes sju artiklar ut och deras vetenskaplighet studerades. Alla sju artiklarna var baserade på kvantitativa studier. Resultatet visade att smärta tillsammans med spiralinsättning var mycket vanligt. Den kategori av kvinnor som upplevde mest smärta var de kvinnor som inte hade fött barn på det naturliga sättet. Svimning och bradycardi förekom också vid spiralinsättningar men detta var inte lika vanligt. Att ge smärtlindring med ibuprofen visade sig inte ge någon effekt vid spiralinsättning. Vid insättningen av en spiral var indikationerna bättre om insättaren hade satt in många spiraler tidigare, då hade spiralinsättningen större chans att lyckas än om insättaren hade satt in få spiraler. / The purpose of this study was to investigate the research described in scientific literature about the problems that arise and the experiences the women get when inserting an IUD. In a literature review seven scientific articles were chosen and their scientific value was evaluated. All seven articles were based on quantitative studies. The results showed that pain connected with IUD insertion was very common. The category of women experiencing most pain was the women who had not given birth the natural way. Fainting and bradycardia were also occurring when inserting an IUD but not so frequent. To give analgesia with ibuprofen showed no effect when inserting an IUD. When inserting an IUD the indications were better for the patient if the inserter had put in many IUD earlier, then the input of the IUD had a better chance to succeed.

Spiral artery (SA) remodeling is a fundamental process during early pregnancy that involves the action of vascular smooth muscle cells (VSMCs), maternal immune cells, but also fetal extravillous trophoblast cells (EVTs) and the extracellular matrix (ECM). Mast cells (MCs) and their mediator chymase, have been identified as prominent players for a sufficient SA remodeling process at the fetal-maternal interface in vivo. In contrast, endocrine disrupting chemicals (EDC), especially Bisphenol A (BPA) and 17-α-ethinylestradiol (EE2), have been shown to have a negative impact on SA remodeling in animal models in vivo. However, neither the mechanisms underlying the positive effects of MCs and chymases for the remodeling process, nor the interference of EDCs on SA remodeling, have been elucidated. The purpose of the present work was to evaluate the effect of MCs and recombinant human chymase CMA1 (rhuCMA1) on the phenotype and/or behavior of VSMCs, EVTs and ECM in vitro. Moreover, the influence of BPA and EE2 on the functionality of EVTs in vitro was observed. Using an immortalized human trophoblast cell line (HTR8/SV-neo), a mouse trophoblast cell line (SM9-2), human primary uterine vascular smooth muscle cells (HUtSMCs) and mouse primary uterine smooth muscle cells (SMCs), we assessed the effects of the human MC cell line HMC-1, the mouse mast cell line MC/9 and rhuCMA1 on VSMCs, EVTs and ECM. Additionally, the HTR- 8/SV-neo cells functionality was evaluated after treatment with BPA or EE2. We found that mouse MC/9 cells induce fibronectin expression and migration in SMCs. Furthermore MC/9 cells increase the proliferation and migration of SM9-2 cells. Both human HMC-1 cells and rhuCMA1 stimulate the migration, proliferation, and change of synthetic/contractile marker expression in HUtSMCs. In addition, HMC-1 cells increase the proliferation and migration of HTR8/SVneo trophoblast cells while having an impact on the expression of tissue remodeling genes. HTR8/SVneo cells presented increased migration rates along with decreased expression of the matrix-metalloproteinase regulator genes (TIMPs) upon treatment with rhuCMA1. Moreover, BPA interfered with HTR-8/SV-neo cell proliferation and reduced MMP2 expression in HTR-8/SV-neo. Interestingly, EE2 had no impact on proliferation or migration but suppressed the MMP2 expression in HTR-8/SV-neo cells. The obtained results indicate that MCs, and partly their mediator chymase CMA1, shape the phenotype and modulate the functionality of VSMCs and EVTs. Collectively, possible mechanisms by which MCs and specifically rhuCMA1 promote SA remodeling were identified. The findings are relevant for the understanding of this crucial step in pregnancy and thus, for the comprehension of dysregulated pathways that can lead to pregnancy complications like fetal growth restriction and preeclampsia. Moreover, this work contributes to the knowledge about how EDCs impact on early pregnancy and highlights the high risk of EDCs exposure disturbing the fundamental reproductive process of SA remodeling.

Bianshi har under en lång tid tillämpats i Shanghais matematikundervisning. Forskaren GuLingyuan gav denna typ av undervisning en definition med benämningen Bianshi år 1981. Eleverna i Shanghai har visat goda resultat i matematik. Därav är det relevant för lärare att undersöka Bianshi och reflektera över om den kan tillämpas samt bidra till en positiv utveckling av elevernas matematiska kunskaper.  Syftet med litteraturstudien är att lyfta vad Bianshi är och dess påverkan på elevernas lärande i matematik. Detta kommer besvaras genom frågeställningarna: hur beskriver forskningBianshi som grund i undervisningen? Vilka positiva och negativa aspekter med Bianshipresenteras i forskning? Litteraturstudiens vetenskapliga källor inhämtades genom sökningar i databaserna ERIC, Primo och Google Scholar. Sökningarna resulterade i 6 vetenskapliga artiklar, 1 vetenskaplig rapport, 1 konferens publikation och 2 kapitel ur antologier. Litteraturen är internationell och skriven på engelska. Vidare analyserades materialet genom inkluderings- och exkluderings kriterier samt en översiktsmatris.  Resultatet visade att Bianshi är ett sätt att undervisa där man använder olika strategier för att variera lektionsinnehållet. Bianshi-undervisning definieras olika i forskning. Även om denna typ av undervisning benämns olika visar resultatet stora likheter, bland annat att forskare lyfter variation av exempeluppgifter, lösningsstrategier och vikten av att använda förkunskaper som bärande delar i Bianshi. Resultatet visar också att Bianshi främjar elevernas matematiska utveckling och skapar ett meningsfullt samt utforskande klassrum. Ytterligare anses bristen på forskning och kravet på goda kunskaper inom den teoretiska ramen vara ett hinder för tillämpningen av Bianshi.