Les bactéries photosynthétiques pourpres comme Rhodopseudomonas acidophila (strain 10050) disposent pour collecter la lumière d’un appareil photosynthétique constitué de complexes protéiques membranaires avec des pigments spécialisés. Cet appareil photosynthétique comprend deux types de collecteurs de lumière (light harversting ou LH) appelés LH1 et LH2 et d’un centre réactionnel (CR). La lumière est principalement absorbée par des pigments photosynthétiques liés au complexe LH2 et l'énergie d'excitation résultante est ensuite transférée au complexe LH1 et, de là au centre réactionnel où elle est transformée en énergie chimique. Les données de cristallographie ont permis de montrer que le complexe LH2 se compose d'un ensemble de 9 sous-unités parfaitement symétriques constituées de deux petites sous-unités protéiques α et β associées à 1 caroténoïde (rhodopine glucoside) et 3 bactériochlorophylles-a. Des expériences de spectroscopie de fluorescence en fonction du temps effectuées sur des complexes LH2 uniques ont montré que l'intensité et la position de transition électronique du complexe pouvaient fortement fluctuer avec le temps. Ces observations décrivent un « désordre dynamique » en lien avec la fonction biologique du complexe LH2, qui montre une efficacité d’utilisation de l’énergie lumineuse. Même si un grand nombre d’études met en avant l’existence de ce « désordre » pour interpréter les données expérimentales de fluorescence, peu de travaux ont examiné au niveau moléculaire, les fluctuations locales ou globales au sein du complexe LH2 qui gouvernent ce désordre. La description moléculaire du désordre dynamique du complexe LH2 permettra une compréhension plus précise de ces complexes capables d’utiliser l’énergie solaire avec une grande efficacité, et sont donc d’une grande importance pour la mise en place de systèmes de production d’énergie renouvelable.L’objectif de ce projet de thèse est de mieux comprendre l’origine de ce « désordre » à l’échelle atomique en employant des approches de dynamiques moléculaires classiques. Pour ce faire, nous avons modélisé le complexe LH2 dans différents environnements biomimétiques constitués de détergents (dimethyldodecylamine-N-oxide (LDAO) et le beta octyle glucoside (bOG)) et d'une membrane de POPC. Une première partie de ce travail a consisté à développer des modèles originaux pour ces détergents ainsi que les différents composants du complexe, et à examiner l'agrégation des molécules de détergents autour du complexe. Pour valider nos modèles, des expériences de diffraction des rayons X aux petits angles (SAXS) ont été réalisées avec les complexes LH2-LDAO et LH2-βOG. Dans un second temps, nous avons plus spécifiquement étudié les interactions peptide-pigment,pigment-pigment en fonction de l’environnement. Nos résultats ont montré des différences significatives concernant la dynamique du complexe et les interactions pigment-pigment et pigment-protéine en fonction de l'environnement. Enfin, afin de relier les variations des interactions entre les différents composants du complexe décrits dans nos simulations, aux variations d’absorption du complexe LH2 et au désordre dynamique, des calculs ab-initio ont été réalisés à partir de structures atomiques représentatives de nos simulations. / Purple photosynthetic bacteria, such as Rhodopseudomonas acidophila (strain 10050), have a synthetic apparatus which is composed by membrane protein complexes with specialized pigments to harvest the light. This photosynthetic apparatus is composed of 2 types of light harvesting (LH) complex called LH1 and LH2, and a reactional center (RC). The light is mainly absorbed by photosynthetic pigments bounded to LH2 complex and the resulting excitation energy is transferred to LH1 complex, then to RC where it is transformed to chemical energy. The crystallography data allowed to show that the LH2 complex is composed of a perfectly symmetrical 9 sub-unit ensemble, formed by 2 small protein sub-unit α and β associated to 1 carotenoid (rhodopine glucoside) and 3 bacteriochlorophylls-a. The spectroscopy fluorescence experiences carried out as a function of time on unique LH2 complexes shown that the intensity and the position of the electronic transition of complexes can strongly fluctuate with the time. These observations describe a « dynamic disorder » linked with the biological function of the LH2 complex, which reveal the efficiency of the use of light energy. Even if the large number of studies highlight the existence of this « disorder » to interpret experimental data of fluorescence, a few number of studies analyzed at molecular level the local or global fluctuations inside of LH2 complex which govern this disorder. The molecular description of the dynamic disorder of LH2 complex will permit more precise comprehension about the ability to use of solar energy of these complexes with a huge efficiency, and thus, they are very important for setting up the sustainable energy production system.The aim of this project thesis is a better understanding the origin of this « disorder » at atomic scale by using classical molecular dynamics approaches. In order to do this, we modeled the LH2 complex in different biomimetic environments composed of detergents (dimethyldodecylamine-N-oxide (LDAO) and the β octyle glucoside (βOG)) and of POPC membrane. The first part of this study consisted in developing original models for these detergents, as well as for the different components of the LH2 complex, and to analyze the aggregation of detergent molecules around the complex. To validate our models, small angle X-ray scattering (SAXS) experiments have been realized with the LH2-LDAO and LH2-βOG complexes. In the second part, we specifically studied the interactions of peptide-pigment and pigment-pigment depending on the environment. Our results revealed significant differences concerning the dynamic of the complex and the interactions of pigment-pigment and pigment-protein depending on the environment. In the end, in order to relate the variations of interactions between the different components of complex, as described in our simulations, to the variations of absorption of the LH2 complex and to dynamic disorder, ab-initio calculations have been done from the representative atomic structures of our simulations.

Detta arbete handlar om vätgasens implementation inom den marina sektorn, med hänsyn till bland annat riskfaktorer, egenskaper hos ämnet samt ekonomiska utmaningar. Syftet med detta arbete var att skapa en lättöversiktlig bild över hur pass lämplig användandet av vätgas skulle vara inom dagens sjöfart. Då vätgasen ännu inte har testats inom någon stor utsträckning till sjöss så kan de flesta rapporter man hittar om vätgas endast redovisa hur ett användande borde se ut och inte hur det faktiskt ska vara. På grund av detta så har det visats sig att detta metodval att ta relevant information från en större mängd olika källor varit rätt väg att gå. Efter att ha studerat vätgasen från flera aspekter så kan man konstatera att det inte skulle vara någon omöjlighet att driva större fartyg på vätgas, men att detta skulle kräva stora satsningar från länder och rederier för att göra det en verklighet. / This work deals with the implementation of hydrogen in the marine sector, considering risk assessments, properties of the substance and economic challenges. The aim of this work was to create a simple overview of how suitable the use of hydrogen would be in today's shipping. Since hydrogen has not yet been tested to a large extent at sea, most reports found about hydrogen can only account for what a usage should look like and not what it actually should be. Because of this, it has been shown that the method of taking relevant information from a wider variety of sources has proved to be the way to go. Having studied hydrogen from several aspects, it can be concluded that it would not be impossible to drive larger ships on hydrogen, but that this would require major efforts from countries and shipping companies to make it possible.

The pace of development in aviation technology is increasing, and there is a constantneed for new concepts to keep up. An innovative concept is desired to reach the netzero emission and sustainability target visualized in Flight path 2050. Introducing digital models and virtualization into aviation fields reduces time consumption onmanual modelling and increases design accuracy. Digital mock-up models also helpin minimizing costs due to errors in the later stage of development or manufacturing. The Institute of Systems Architecture in Aeronautics at German AerospaceCenter (DLR) works in digitizing cabin design environments with extensive implementation of the Knowledge-Based Engineering (KBE) approach. The virtual cabindesign system tool also known as Fuselage Geometry Assembler (FUGA) providesa digital model of the cabin of both single and twin aisle configurations of commercial aircraft. The information of aircraft characteristics is provided to FUGA using Common Parametric Aircraft Configuration Schema (CPACS). CPACS coupled with FUGA provides the user with a consistent model of aircraft and cabindesign, when viewed through a virtual platform provides an immersive experienceto be inside an aircraft cabin before physical production. The multidisciplinary capability of FUGA provides experts from different disciplines to perform analysis such as vibration analysis on the cabin environment. For ease of usage and better visualization of information from FUGA, a web-based application through Flask is hosted for FUGA. This enables the user to access the FUGA tool without the needof installing the tool on their devices. With the world now moving towards a greener approach, an alternative propulsion system may require a different fuel tank configuration. Retro-fit of liquid hydrogen fuel tank into an existing aircraft’s fuselage is done using FUGA tool and aircraft performance analysis is conducted and the outcomes are studied. The enhanced and advanced model of twin-aisle configuration, now on par with single-aisle configuration is used for hydrogen tank sensitivity analysis. The comparative study of different aisle configurations retro-fitted with liquidhydrogen fuel tank is further conducted for arriving at an optimal design point fora balance in range and passenger capacity.

No description available.

The aviation industry plays a significant role in global connectivity and economic growthbut has substantial negative environmental impacts, particularly in terms of carbondioxide emissions. According to a study by the European parliament, the aviationindustry accounts for 0,4 % of greenhouse gas emissions within the EU and 3,4% forinternational flights. In response to these environmental issues, liquid hydrogen is seenas a promising choice, offering efficiency as a clean energy source, especially whenproduced through electrolysis, as well as higher energy density per volume, making itattractive for the aviation industry where energy and weight optimization are crucial. However, the challenge of using hydrogen as fuel lies in designing a tank that canwithstand extreme conditions, such as low temperature and high pressure , while alsominimizing the risk of flammability and explosion. Additionally the right materials mustbe chosen to resist hydrogen embrittlement. This project aims to design a hydrogentank for aircraft that meets the requirements specified in this study. This will be achievedthrough a literature review, numerical simulations with SolidWorks FEM to test differenttank shapes and materials, and the use of Python code to calculate different spatialparameters.The results indicate that a cylindrical shape is the most optimal choice for the tank, andfour materials have been identified as suitable, with aluminum alloys showing moreadvantages compared to stainless steel due to reduced weight with similar strength.

Light-harvesting in nature is known to work differently than conventional man-made solar cells. Recent studies found electronic excitations, delocalised over several chromophores, and a soft, vibrating structural environment to be key schemes that might protect and direct energy transfer yielding increased harvest efficiencies even under adversary conditions. Unfortunately, testing realistic models of noise assisted transport at the quantum level is challenging due to the intractable size of the environmental wave function. I developed a powerful tree tensor network states (TTNS) method that finds an optimally compressed explicit representation of the combined electronic and vibrational quantum state. With TTNS it is possible to simulate exciton-phonon quantum dynamics from small molecules to larger complexes, modelled as an open quantum system with multiple bosonic environments. After benchmarking the method on the minimal spin-boson model by reproducing ground state properties and dynamics that have been reported using other methods, the vibrational quantum state is harnessed to investigate environmental dynamics and its correlation with the spin system. To enable simulations of realistic non-Born-Oppenheimer molecular quantum dynamics, a clustering algorithm and novel entanglement renormalisation tensors are employed to interface TTNS with ab initio density functional theory (DFT). A thereby generated model of a pentacene dimer containing 252 vibrational normal modes was simulated with TTNS reproducing exciton dynamics in agreement with experimental results. Based on the environmental state, the (potential) energy surfaces, underlying the observed singlet fission dynamics, were calculated yielding unprecedented insight into the super-exchange mediated avoided crossing mechanism that produces ultrafast and high yield singlet fission. This combination of DFT and TTNS is a step towards large scale material exploration that can accurately predict excited states properties and dynamics. Furthermore, application to biomolecular systems, such as photosynthetic complexes, may give valuable insights into novel environmental engineering principles for the design of artificial light-harvesting systems.