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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

En energifull framtid? : en undersökning av åsikters och attityders påverkan på etablering av små modulära reaktorer i Säffle och Karlskoga kommun

Tonell, Vera, Frostvik, Anna January 2023 (has links)
Denna uppsats undersöker hur framtida etableringar av SMR, små modulära kärnkraftsreaktorer, påverkas av attityder och åsikter och hur detta hanteras av kommunala politiker. Detta är undersökt med fokus på kommunerna Karlskoga och Säffle, både belägna i Värmland. Undersökningen genomfördes genom en kvalitativ intervjustudie där fem identifierade nyckelpersoner intervjuades. Studiens empiri är grundad på information och kunskap från intervjuerna. Empirin diskuteras genom ett teoretiskt ramverk som består av sociotekniskt system, planerings- och etableringsprocess och energisäkerhet. Resultatet indikerar att etablering av SMR bör ses som ett sociotekniskt system. Det innebär att tekniken inte kan stå för sig själv, utan måste ses i en social kontext där faktorerna attityder och åsikterär extra viktiga. Dessa faktorer påverkas i sin tur av deltagande, lyhördhet, information och acceptans. Detta är fyra förhållningssätt som kommunala politiker måste förhålla sig till vid planerings- och etableringsprocesser. Slutligen konstateras att etableringprocesser av SMR i Sverige är lång och tidskrävande. De tekniska osäkerheterna måste lösas, de ekonomiska villkoren måste finnas, det organisatoriska måste få en form och de rättsliga förutsättningarna måste klubbas igenom. Viktigast är dock ett kontinuerligt arbete med attityder och åsikter.
22

Adapted data collection in field utilizing RMR and the Q-system

Olsson, Amanda January 2024 (has links)
The focus on slope stability has increased rapidly in Norway over the last years due to several unwanted landslides. In Norway, the most used method today to classify the rock mass and to determine the required reinforcement, is the Q-system. In addition to that the RMR method is also a commonly used method. However, since both the RMR and the Q-system is created to be used for underground constructions, their slope adaptations (Q-slope and SMR) has been developed. These adaptations will also be evaluated in this thesis. They will be used to examine if there is a correlation between the classification systems and the installed support on site. This thesis will only focus on slopes and not tunnels, as a limit to the scope investigated.  The joints properties at the investigated sites are taken both from engineering geologist reports and field mapping. The mapped joints will be analyzed in Dips to determine the major joint sets and by using the kinematic analysis tool determine what failure mechanisms these joint sets may create. These joint sets will be further evaluated through numerical analysis (with e.g. RocPlane, Swedge or RocTopple) dependent on their failure mechanism. The rock and joint data for calculation is gathered from three different sites, which are all part of the same project where the traffic capacity of the European route E18 through Porsgrunn, outside of Oslo, is increased. In both Blåfjell and Bjønnås the rock mass is larvikite, but in Grenland the rock mass investigated is sandstone. However, the sandstone in the Grenland has undergone contact metamorphosis, which changes the characteristics of the rock mass and creating a much stronger sandstone.  Generally, the rock mass investigated is classified to be of similar quality which gives them the same strength. Consequently, it is difficult to determine any kind of correlation between the sites. The results do not indicate the expected relationship that a stronger rock mass would need less reinforcement. In addition, it is also observed that the classification systems generally recommend more shotcrete that what is installed on site. When comparing the different classification systems, it can be seen that the Q-system generally categorize the rock mass in a lower category, indicating a weaker rock mass, compared to RMR and SMR. This then results in that the rock masses investigated is classified to be ranging from Poor to Good, dependent on the classification method.   Keywords: Rock mass classification, Q-slope, SMR, Slope stability.
23

Utvecklingsbehov av probabilistisk säkerhetsanalys (PSA) för applicering på SMR:er / Development needs of probabilistic safety assessment (PSA) for SMR applications

Emilia, Udd January 2024 (has links)
Nuclear power is an important part of Sweden's energy system and contributes with about 30 % of the supplied electric energy. Interest in new construction is currently high and one type of reactor that may be built is small modular reactors, SMRs. A method that is used to evaluate the safety of a traditional nuclear power plant is the so called probabilistic safety assessment (PSA). An important question is if PSA is applicable to SMRs. This thesis examines differences between a BWRX-300 type SMR and a generic boiling water reactor to investigate if the traditional PSA method is applicable to SMRs and what characteristics that may affect the results.  To investigate the topic, a simplified PSA analysis is carried out at level 1 for five different initiating events: extreme snowfall, loss of cooling accident, loss of main feedwater, loss of offsite power supply and transient. These are then compared to a model of a generic BWR reactor.  The conclusions that emerge from the analysis are that the traditional PSA method can be applied for SMRs of the BWRX-300 type. The features that distinguish the BWRX-300 compared to a generic BWR are mainly that the SMR is smaller in size and power and the influence of the passive safety systems. This results in a lower core damage frequency. Some the areas where the PSA method could be developed for SMRs are the analysis of passive components and passive functions.
24

Développement d’un modèle expérimental porcin d’autorétroperfusion myocardique à coeur battant : évaluation des réponses hémodynamiques et cardiaques avant et après occlusion de l’artère interventriculaire antérieure : potentialités d’applications cliniques / Development of a porcine beating-heart model of self-myocardial retroperfusion : evaluation of hemodynamic and cardiac responses to ischemia and clinical applications

Grandmougin, Daniel 01 June 2018 (has links)
Partie I : Objectifs. Ce travail propose une étude anatomique du coeur de porc afin d’élaborer des recommandations pour la réalisation d’une chirurgie cardiaque expérimentale. Matériels et méthodes. 16 porcs ont été étudiés. Le réseau coronaire artériel a été étudié chirurgicalement (n=13) et angiographiquement (n=10). Le réseau veineux coronaire a été analysé par dissections anatomiques (n=13) et injections rétrogrades de bleu de méthylène via le sinus coronaire (n=8). Résultats. Le positionnement intrapéricardique spécifique du coeur de porc, limite l’accès à l’aorte ascendante et à l’oreillette droite et nécessite des précautions particulières pour la réalisation d’une sternotomie et d’une canulation de l’aorte ascendante avec cardioplégie antérograde par la racine de l’aorte. Le réseau coronaire artériel est comparable au réseau humain (réseau droit dominant: 70%). Le sinus coronaire reçoit 4 afférences contre 3 chez l’homme. L’étude de la distribution de surface du réseau veineux nécessite la ligature préalable de la veine azygos gauche et confirme une asymétrie de perfusion au détriment du VD. La paroi antérieure du VD étant drainée par des petites veines cardiaques indépendantes du sinus coronaire. Conclusions. La connaissance des spécificités anatomiques cardiaques du porc a permis d’établir des recommandations pour la réalisation du modèle d’autorétroperfusion myocardique et plus largement de procédures chirurgicales cardiaques expérimentales sécurisées. Partie II : Objectifs. La perfusion rétrograde dans le sinus coronaire est utilisée pour la diffusion d’une solution de cardioplégie. Nous avons développé un modèle porcin d’autorétroperfusion myocardique à coeur battant (SMR) utilisant le réseau veineux coronaire pour assurer l’oxygénation du myocarde ventriculaire gauche. Ce modèle nous a permis d’évaluer les réponses hémodynamiques et cardiaques induites par SMR avant et après occlusion de l’artère IVA. Matériels et Méthodes. Une dérivation entre l’aorte ascendante et le sinus coronaire a été mise en place pour assurer une perfusion rétrograde sélective de la grande veine coronaire en sang oxygéné (SMR). Un groupe Contrôle (n=6) a permis de collecter des données physiologiques de référence et un groupe SMR (n=6) a été spécifiquement dédié à l’évaluation du concept d’autorétroperfusion myocardique après occlusion de l’artère IVA pendant au moins 240 minutes. Le débit cardiaque (CO), la pression maximale intra-VG (Pmax in-LV), le volume éjecté (SV), la fraction d’éjection ventriculaire gauche (FEVG), la durée diastolique (DD), la fréquence cardiaque (HR) et la pression artérielle systémique ont été monitorés en continu durant la période d’autorétroperfusion au moyen d’un cathéter de conductance type Millar® avant et après occlusion de l’IVA. La qualité de la perfusion systémique périphérique a été évaluée par l’analyse de la microcirculation sublinguale. En fin de procédure, les coeurs étaient prélevés pour une analyse histologique. Résultats. L’évaluation échographique de la FEVG était biaisée par la sternotomie alors que celle réalisée par le cathéter de conductance ne l’était pas. Le débit cardiaque après sternotomie a chuté en moyenne de 7.51% (P < 0.05). L’autorétroperfusion avec artère IVA perméable a généré des effets inotropes positifs, caractérisés par une augmentation du CO, du SV, de la Pmax in-LV et de la FEVG (P <0.0001). Après occlusion de l’IVA, l’autorétroperfusion a assuré, durant 240 minutes, une oxygénation myocardique et une compensation hémodynamique garantissant la préservation de la perfusion périphérique. L’analyse histologique a confirmé l’absence d’infarctus myocardique. Conclusions. L’autorétroperfusion myocardique a confirmé des propriétés inotropes positives et protectrices contre l’ischémie ouvrant des perspectives d’applications intéressantes / Part I: Objectives. This work reports an anatomic study of swine heart in order to produce technical recommendations and achieve successful experimental cardiac surgical procedures. Methods. 16 swines were studied. Coronary artery vessels were surgically (n=13) and angiographically (n=10) assessed. Coronary venous vessels were studied by anatomic dissections (n=13) and retrograde injection of methylene blue through the coronary sinus (n=8). Results. Specific pericardial positioning of swine heart dramatically differs from human heart resulting in a limited access to ascending aorta and right atrium, requiring surgical precautions to perform a safe sternotomy and canulation of ascending aorta with an antegrade cardioplegia. Arterial coronary pattern is similar to that of humans (right dominant supply: 70%). Pig coronary sinus receives 4 main branches vs 3 in human sinus. Preliminary ligation of the left azygos vein is required to visualize the surface distribution of methylene blue within the venous vessels, thereby confirming an optimized perfusion of the left ventricle whereas the right ventricle remains poorly perfused. This asymmetry of perfusion results from a specific venous drainage of the right ventricle through small cardiac veins disconnected from coronary sinus. Conclusions. Anatomic knowledge of swine heart validated surgical guidelines for designing the model of self-myocardial retroperfusion and safely performing experimental cardiac surgical procedures. Part II: Background. Retrograde perfusion into the coronary sinus is used to deliver cardioplegia. We developed an in-vivo porcine beating-heart model of self-myocardial retroperfusion (SMR) using the venous route to supply myocardial oxygenation and sought to assess hemodynamic and cardiac responses triggered by SMR before and after a prolonged occlusion of the LAD.Methods. A bypass-line between the ascending aorta and the coronary sinus was made to perform a selective retrograde perfusion of the great cardiac vein with oxygenated blood (SMR). A Control group (n=6) was assigned to collect baseline data, and an SMR group (n=6) was dedicated to undergo SMR with occlusion of LAD for 240 minutes. Cardiac output (CO), maximal pressure in the LV (Pmax in-LV), stroke volume (SV), left ventricular ejection fraction (LVEF), diastolic durations, heart rate, and arterial systemic pressure were evaluated with conductance catheters for the following periods: basal (before SMR), SMR with patent LAD, and SMR with occluded LAD. In order to assess peripheral perfusion, patterns of sublingual microcirculation were analyzed. At the end of the procedures, the hearts were harvested for histology. Results. Echographic LVEF evaluation was affected by sternotomy, but conductance catheter evaluation was not. Following pericardiotomy, CO decreased by 7.51% (P < 0.05). SMR with patent LAD showed inotropic properties with improvements in CO, SV, Pmax in-LV and LVEF (P < 0.0001). Following LAD occlusion, SMR supplied myocardial oxygenation with hemodynamic compensation and preserved the peripheral perfusion. Histology confirmed no signs of infarct. Conclusions. SMR showed capacities to produce inotropic effects and protect against ischemia, opening interesting potential applications
25

Uso de nubes de puntos 3D para identificación y caracterización de familias de discontinuidades planas en afloramientos rocosos y evaluación de la calidad geomecánica

Riquelme, Adrián 25 September 2015 (has links)
En este trabajo se estudia el uso de las nubes de puntos en 3D, es decir, un conjunto de puntos en un sistema de referencia cartesiano en R3, para la identificación y caracterización de las discontinuidades que afloran en un macizo rocoso y su aplicación al campo de la Mecánica de Rocas. Las nubes de puntos utilizadas se han adquirido mediante tres técnicas: sintéticas, 3D laser scanner y la técnica de fotogrametría digital Structure From Motion (SfM). El enfoque está orientado a la extracción y caracterización de familias de discontinuidades y su aplicación a la evaluación de la calidad de un talud rocoso mediante la clasificación geomecánica Slope Mass Rating (SMR). El contenido de la misma está dividido en tres bloques, como son: (1) metodología de extracción de discontinuidades y clasificación de la nube de puntos 3D; (2) análisis de espaciados normales en nubes de puntos 3D; y (3) análisis de la evaluación de la calidad geomecánica de taludes rocoso mediante la clasificación geomecánica SMR a partir de nubes de puntos 3D. La primera línea de investigación consiste en el estudio de las nubes de puntos 3D con la finalidad de extraer y caracterizar las discontinuidades planas presentes en la superficie de un macizo rocoso. En primer lugar, se ha recopilado información de las metodologías existentes y la disponibilidad de programas para su estudio. Esto motivó la decisión de investigar y diseñar un proceso de clasificación novedoso, que muestre todos los pasos para su programación e incluso ofreciendo el código programado a la comunidad científica bajo licencia GNU GPL. De esta forma, se ha diseñado una novedosa metodología y se ha programado un software que analiza nubes de puntos 3D de forma semi-automática, permitiendo al usuario interactuar con el proceso de clasificación. Dicho software se llama Discontinuity Set Extractor (DSE). El método se ha validado empleando nubes de puntos sintéticas y adquiridas con 3D laser scanner. En primer lugar, este código analiza la nube de puntos efectuando un test de coplanaridad para cada punto y sus vecinos próximos para, a continuación, calcular el vector normal de la superficie en el punto estudiado. En segundo lugar, se representan los polos de los vectores normales calculados en el paso previo en una falsilla estereográfica. A continuación se calcula la densidad de los polos y los polos con mayor densidad o polos principales. Estos indican las orientaciones de la superficie más representadas, y por tanto las familias de discontinuidades. En tercer lugar, se asigna a cada punto una familia en dependencia del ángulo formado por el vector normal del punto y el de la familia. En este punto el usuario puede visualizar la nube de puntos clasificada con las familias de discontinuidades que ha determinado para validar el resultado intermedio. En cuarto lugar, se realiza un análisis cluster en el que se determina la agrupación de puntos según planos para cada familia (clusters). A continuación, se filtran aquellos que no tengan un número de puntos suficiente y se determina la ecuación de cada plano. Finalmente, se exportan los resultados de la clasificación a un archivo de texto para su análisis y representación en otros programas. La segunda línea de investigación consiste en el estudio del espaciado entre discontinuidades planas que afloran en macizos rocosos a partir de nubes de puntos 3D. Se desarrolló una metodología de cálculo de espaciados a partir de nubes de puntos 3D previamente clasificadas con el fin de determinar las relaciones espaciales entre planos de cada familia y calcular el espaciado normal. El fundamento novedoso del método propuesto es determinar el espaciado normal de familia basándonos en los mismos principios que en campo, pero sin la restricción de las limitaciones espaciales, condiciones de inseguridad y dificultades inherentes al proceso. Se consideraron dos aspectos de las discontinuidades: su persistencia finita o infinita, siendo la primera el aspecto más novedoso de esta publicación. El desarrollo y aplicación del método a varios casos de estudio permitió determinar su ámbito de aplicación. La validación se llevó a cabo con nubes de puntos sintéticas y adquiridas con 3D laser scanner. La tercera línea de investigación consiste en el análisis de la aplicación de la información obtenida con nubes de puntos 3D a la evaluación de la calidad de un talud rocoso mediante la clasificación geomecánica SMR. El análisis se centró en la influencia del uso de orientaciones determinadas con distintas fuentes de información (datos de campo y técnicas de adquisición remota) en la determinación de los factores de ajuste y al valor del índice SMR. Los resultados de este análisis muestran que el uso de fuentes de información y técnicas ampliamente aceptadas pueden ocasionar cambios en la evaluación de la calidad del talud rocoso de hasta una clase geomecánica (es decir, 20 unidades). Asimismo, los análisis realizados han permitido constatar la validez del índice SMR para cartografiar zonas inestables de un talud. Los métodos y programas informáticos desarrollados suponen un importante avance científico para el uso de nubes de puntos 3D para: (1) el estudio y caracterización de las discontinuidades de los macizos rocosos y (2) su aplicación a la evaluación de la calidad de taludes en roca mediante las clasificaciones geomecánicas. Asimismo, las conclusiones obtenidas y los medios y métodos empleados en esta tesis doctoral podrán ser contrastadas y utilizados por otros investigadores, al estar disponibles en la web del autor bajo licencia GNU GPL.
26

Gud är inte skaparen : Svenska nutida nazister och nazistmyten

Martin, Christofer January 2011 (has links)
This essay is about the modern Swedish Nazi movement in relation to the German Nazi movement before and during the Second World War. The analysis is made using the Nazi Myth theory as described by French philosophers Philippe Lacoue-Labarthe &amp; Jean-Luc Nancy. Theory and method are aimed at analysing the Nazi movement as a religious one. In this essay I have identified five main Nazi Myth elements required to realize Nazi ideals and embraced by original German Nazis. Through text analysis I have studied how Swedish Nazis use and reproduce these elements.The result will show that the main elements are well represented in modern Swedish Nazi texts and must be considered as central and bearing in modern Swedish Nazism. However, modern Swedish Nazism is also different from original German Nazism in some ways, for example in view of race, land and art.
27

Solution Structures and Dynamics of Conotoxins and Small MutS Related Domain from Helicobacter Pylori MutS2

Kumar, Kancherla Aswani January 2015 (has links) (PDF)
The work presented in this thesis describes the determination of structures of peptides and proteins at atomic resolution. Nuclear Magnetic Resonance (NMR) spectroscopy was used as the principal method of investigation. The thesis is divided into three parts. Part I of the thesis consists of chapters 1 to 4, and deals with structural studies of two novel conotoxins. Part II of the thesis consists of chapter 5 and deals with structural studies of Small MutS Related (Smr) domain from Helicobacter pylori MutS2. Part III of the thesis consists of Appendices A to D. Appendix A describes implementation of a novel pulse sequence for determination of disulfide connectivity using long-range 13 C–13 C scalar couplings across disulfide bonds. Appendices B, C and D contain supplementary infor- mation (acquisition parameters and chemical shifts) for the structural studies presented in parts I and II of the thesis. Part I: Structural studies of novel conotoxins from Conus monile Chapter 1 gives a brief overview of the conotoxins and their structural studies. The first half of the chapter describes biosynthesis, classification schemes, nomenclature, com- monly observed post-translational modifications and applications of conotoxins. The latter half of this chapter summarizes the challenges involved in the structural studies of conotoxins in light of the recent developments in integrated transcriptomic and venomic studies of conotoxins. The key homonuclear and heteronuclear NMR experiments that are employed for structural studies of conotoxins are summarized. Emphasis was laid on describing the spectral features and the structural information that can be gleaned from these experiments. Finally, the current mass spectrometric and NMR methods available for determination of disulfide connectivity are discussed Chapter 2 describes sample preparation and preliminary biophysical characteriza- tion of a conotoxin Mo3964 that contains a hitherto uncharacterized cysteine framework (C–CC–C–C–C). The sequence of Mo3964 was identified at the nucleic acid level as a cDNA clone. Analysis of the signal sequence revealed that the toxin belongs to the M-superfamily, while the cysteine framework bears more resemblance to O- and K- super- family of conotoxins. Structural studies were initiated to determine the disulfide connec- tivity, tertiary structure and biological activity. The gene corresponding to the mature toxin sequence was cloned in a bacterial expression vector pET21a(+) as a C-terminal tag to the cytochrome b5 fusion protein host system. The fusion protein was obtained by recombinant expression using the bacterial expression host E. coli BL21(DE3) and the mature toxin was obtained by either enzymatic or chemical cleavage of the fusion protein followed by size exclusion chromatography and reverse phase HPLC. Proton 1D NMR spectra of the purified peptide exhibited sharp lines and good spec- tral dispersion indicating that molecule was well folded. Formation of disulfide bonds in the mature toxin was ascertained by high resolution mass spectra of intact and chemically modified Mo3964. The peptide toxin exhibited remarkable stability to chemical denatu- ration and proteolytic digestion. Spectroscopic studies clearly showed that Mo3964 pos- sesses a very stable and well defined structure as long as its disulfide bonds are intact. Analytical size exclusion chromatography and Multi Angle Light Scattering (MALS) studies showed that Mo3964 exists in solution as monomer albeit with a non-globular structure. Electrophysiological studies showed that Mo3964 inhibits outward potassium currents in rat Dorsal Root Ganglion (DRG) neurons and increases the reversal potential of rat voltage gated sodium channel rNav 1.2 stably expressed on Chinese Hamster Ovary (CHO) cells at peptide concentrations as low as 10 nM. Chapter 3 describes the determination of disulfide connectivity and tertiary stricture of Mo3964. Initial attempts to determine disulfide connectivity using direct fragmenta- tion of the intact peptide in the mass spectrometer failed due to the relatively large size of the molecule and its resistance to endoproteases. Partial reduction alkylation based methods failed as the first stage of partial reduction gave rise to a mixture of various single disulfide bond reduced species which could not be separated from each other. Subsequently, information about the disulfide connectivity was obtained using a method that does not necessitate separation of such a mixture of single disulfide bond reduced species. This method involves partial reduction, cyanylation of the reduced cysteines and alkali mediated cleavage of the peptide backbone on the N-terminus of cyanylated cysteines. Structural studies were carried out using homonuclear and heteronuclear NMR meth- ods. The hydrogen bond network and hence topology of the molecule was determined with high accuracy using the long-range HNCO-COSY experiment that correlates hydrogen- bond donor-acceptor pairs. This experiment utilizes the three bond heteronuclear scalar coupling, i.e., the h3JN C O′ coupling across the hydrogen bonds. All these restraints proved crucial to the assignment of the disulfide connectivity in Mo3964, given its novel cysteine framework. The structure of Mo3964 was calculated using a total of 549 NOE distance restraints, 84 dihedral angle restraints and 28 hydrogen bond distance restraints. The tertiary structure was constructed from the disulfide connectivity pattern 1–3, 2–5 and 4–6, that is hitherto undescribed for the M–superfamily conotoxins. The ensemble of structures showed a backbone Root Mean Square Deviation of 0.68 ± 0.18 Å, with 87% and 13% of the backbone dihedral (φ, ψ) angles lying in the most favored and additional allowed regions of the Ramachandran map. The remarkable stability and anomalous spectral properties exhibited by Mo3964 could be rationalized using the disulfide connectivity and the tertiary structure. The tertiary structural fold has not been described for any of the known Conus peptides. Further, a search for structures similar to that of Mo3964 using the web server DALI returned no hits indicating that the peptide scaffold of Mo3964 has no structural homologues. Hence, the conotoxin Mo3964 represents a new bioactive peptide fold that is stabilized by disulfide bonds and adds to the existing repertoire of scaffolds that can be used to design stable bioactive peptide molecules. The structure of Mo3964 was submitted to the Protein Data Bank (PDB ID: 2MW7)[1]. Chapter 4 describes the structural studies of a 17 residue, single disulfide containing conopeptide Mo1853. The samples for structural studies were obtained either by chemical synthesis or by recombinant expression methods. Structural studies using homonuclear solution NMR methods revealed that Mo1853 exists as two equally populated cis and trans X–Pro conformers which are in slow exchange regime, compared to the chemical shift timescale. Sequence specific assignments were obtained for both the conformers by analysis of homonuclear 2D 1 H,1H–DQF–COSY,1H,1 H–TOCSY, 1H,1 H–NOESY and 1H,1 H–ROESY spectra. Temperature dependence of chemical shifts was measured and coalescence was observed for two amide protons at 318 K. At this temperature, the rate of exchange and the free energy of activation were determined to be 59 Hz and ≈ 67.2 kJ mol−1 respectively. The evidence for this conformational equilibrium was also observed as exchange correlation peaks in the 2D- NOESY and ROESY spectra. Tertiary structures of both the cis and trans conformers were determined using distance restraints, backbone dihedral angle restraints, the disulfide bond restraint and the cis or trans conformation of the X–Pro peptide bond. Tertiary structures of both the conformers consist of a 29-membered macro-cyclic ring formed by 9 amino acid residues which are cyclized by side chain to side chain disulfide bond. The conformation of the X–Pro peptide bond which is located within this macro-cyclic ring causes the cis structure to be compact and the trans structure to be in an extended form. Analysis of the tertiary structures indicated that the trans conformer is stabilized by hydrogen bonds while the cis conformer is likely to be stabilized by hydrophobic interactions. This was further corroborated by the fact that at lower temperatures, the hydrophobic interactions became weaker reducing the population of the cis conformer with respect to that of the trans conformer. Preliminary electrophysiological studies carried out on rat DRG neurons indicate that Mo1853 transiently reduces late outward potassium currents. Part II: Structural studies of Small MutS Related (Smr) domain from Helicobacter pylori MutS2 Chapter 5 presents the solution NMR studies of the Smr domain from MutS2 of H. pylori , henceforth called as HpSmr. In H. pylori , MutS2 is involved in suppression of homologous recombination and its Smr domain was shown to be necessary for this activity. As of date, in spite of the availability of structural information for the Smr domain, unambiguous identification of the residues involved in metal binding, DNA binding and catalysis remains elusive. Structural studies were carried out on two different constructs of HpSmr viz., HpSmr– (His)6 and GSHM–HpSmr, with and without the hexahistidine tag respectively. Se- quence specific assignments of HpSmr–(His)6 were obtained at two different sample pH conditions viz., pH 8.0 and pH 5.35 using the standard suite of triple resonance NMR experiments. Since, valines and leucines constitute about 25% of the total number of amino acid residues in HpSmr–(His)6 , stereospecific assignments were obtained for di- astereotopic methyl groups of these residues by preparing a fractionally 13C labeled sample of HpSmr–(His)6 . Solution structure of HpSmr–(His)6 at pH 8.0 was determined using 766 NOE restraints, 170 backbone dihedral angle restraints and 70 hydrogen bond distance restraints. The tertiary structure exhibits the canonical α/β sandwich fold ex- hibited by all the other known structures of Smr domains. Further, NMR studies and analytical gel filtration studies indicated the presence of pH dependent conformational exchange in HpSmr that involves strand to coil transition in the C-terminal β-strand. In order ascertain that the conformational equilibrium is not at an artifact caused by the C-terminal hexa-histidine-tag, HpSmr protein construct GSHM–HpSmr, which does not have the hexa-histidine-tag, was prepared. Conformational exchange was observed in this construct as well. The preliminary NMR evidence suggests that the conformational exchange is caused by pH dependent cis–trans isomerization of a semi-conserved Proline residue Pro66 . We have hypothesized that the pH dependent modulation of the activity of Smr domain of MutS2 can be advantageous to H. pylori . Such a regulation could help the bacteria to achieve optimal rate of homologous recombination in response to changes in pH, which is necessary for maintaining homeostasis and tiding over stress conditions. Part III: Appendix Appendix A describes an NMR pulse program LRCC_CH2 that was designed with the aim of determining disulfide connectivity using long-range 13C–13 C (C β –C β ′ ) couplings across the disulfide bond. This experiment is a modification of an earlier experiment pub- lished by Bax and co-workers designed to measure the side-chain χ3 dihedral angle in me- thionines. The experiment described here is optimized for the detection of 3 bond scalar coupled methylene carbons. The details of modifications introduced in LRCC_CH2, its product operator analysis, a representative spectrum acquired on [U-13C,15 N]–Mo3964, short-comings and future directions are described. The C programming code that was used to implement the pulse program is also included in the appendix. Appendices B, C and D contain the supplementary information (acquisition pa- rameters for the NMR experiments and chemical shifts) for the structural studies carried out on Mo3964, Mo1853 and HpSmr.
28

Inženýrskogeologické poměry mostu přes Vltavu na stavbě 519 silničního okruhu kolem Prahy / Engineering geology conditions of a motorway bridge over Vltava river in Prague

Polák, Zdeněk January 2011 (has links)
Tato diplomová práce se zabývá zhodnocením inženýrskogeologických poměrů mostu na stavbě č. 519 silničního okruhu kolem Prahy včetně vyšetření stability skalních svahů v místě předpokládané výstavby. Jedná se o přemostění hlubokého erozního údolí Vltavy, na jehož svazích vystupují na povrch horniny svrchnoproterozoického stáří. Na lokalitě byly zhodnoceny pomocí rešerše archivních podkladů, vlastní rekognoskace a laboratorních zkoušek, geologické, hydrogeologické a inženýrskogeologické poměry, které jsou přehledně uvedeny v inženýrskogeologické mapě v měřítku 1:2000 a řezu 1:500. Jako podklad pro vyhodnocení stability skalních svahů sloužila podrobná dokumentace skalních výchozů. Samotné vyšetření stability proběhlo pomocí klasifikace Slope Mass Ratting a Marklandova testu pro stereografickou projekci. Na výstupech práce je souhrnně popsán horninový masiv včetně mapy stability skalních svahů v měřítku 1:500 a popsány základové poměry uvažovaného mostu.
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Verification of the fluid dynamics modules of the multiphysics simulation framework MOOSE : A work to test a candidate software for molten salt reactor analysis

Gustafsson, Erik January 2022 (has links)
This is a report of a verification study of the multiphysics simulation framework MOOSE which was preformed at the company Seaborg Technologies. In the process of designing molten salt reactors there is a special need of making credible multiphysics simulations since the fuel is in motion. In this study the incompressible version of Navier-Stokes equations of finite volumes available in the Navier-Stokes module of the MOOSE framework is verified by modelling and simulations of fluid flow and heat transfer in two different systems with available benchmarks. The first system, a thin buoyancy driven molten sodium hydroxide test loop which is verified by a similar model made with the high fidelity CFD software STAR-CCM+ as benchmark. The second system, forced convection of air through a straight pipe with heated walls which is verified by comparisons with an analytical solution. The resulting velocity profiles from simulations of the first system corresponds well with the benchmark but certain conclusions can not be drawn from it since the the transient simulations stops to converge before reaching equilibrium. The results from simulations of the second system corresponds well with the analytical solution and no convergence issues arise. The conclusion from the results is that the incompressible version of Navier-Stokes equations of finite volumes available in the Navier-Stokes module of the MOOSE framework has potential to be used in multiphysics simulations of molten salt reactors but seemingly not in cases of buoyancy driven flows in thin geometries. Two proposals for further work is recommended. The first is that this implementation is applied in a context with forced fluid flow or a context with thicker fluid domain. The second proposal is that the other available abilities of MOOSE such as finite element method and/or the compressible version of the Navier-Stokes equations should be tested.
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​​​Små modulära reaktorer i Sverige – ett nuläge​​ / Small Modular Reactors in Sweden – Current Situation

Östlund, Theo, Olsson, William, Kärrman, Simon January 2023 (has links)
Sweden has long had the goal of phasing out its nuclear power. However, both public opinion and politics have shifted in response to the climate and energy crisis, which demands fossil-free energy production. At the same time, small modular reactors (SMRs) have begun to be developed, and several players in Sweden have started exploring this technology. SMRs are smaller versions of conventional nuclear reactors but built in a modular fashion. The advantage of modularity is that the reactors can be produced in series, easily maintained, and their smaller size allows for more flexible placement and lower initial investment. Based on the above, this study examines how current nuclear power actors in Sweden view the development of SMRs.  To answer this question, semi-structured interviews were conducted with representatives from Fortum, Sydkraft Sverige (Uniper), and Kärnfull Next, all of which are active in nuclear power in Sweden. The study shows that the actors see the biggest advantages of SMRs as their modularity, relatively low investment requirements, and more flexible placement, which enables more efficient utilization. However, they believe that the development of SMRs is heavily constrained by current legislation and licensing processes. These are designed to promote the limitation and decommissioning of conventional nuclear power, and according to the respondents, they make successful SMR development impossible. The consequence is that the regulatory framework is more restrictive towards SMRs and hampers the ability to leverage the advantages of SMRs over conventional nuclear power. Furthermore, the respondents believe that there is a skills shortage in nuclear power that will need to be addressed in order to successfully develop SMRs in Sweden. / Sverige har länge haft målet att avveckla sin kärnkraft. Däremot har både opinionen och politiken vänt i frågan och ändrat uppfattning i spåren av klimat- och energikrisen som efterfrågar fossilfri energiproduktion. Samtidigt har små modulära reaktorer (SMR) börjat utvecklas och ett flertal aktörer i Sverige har börjat utforska tekniken. SMR är en mindre version av en konventionell kärnkraftsreaktor men modulärt uppbyggd. Fördelen med modulariteten är att reaktorerna kan serieproducerads, lättare underhållas och dess mindre storlek möjliggör friare placering och mindre initial investering. Med bakgrund i ovanstående undersöker arbetet hur ser nuvarande aktörer inom kärnkraft på utvecklingen av SMR i Sverige? För att besvara frågeställningen genomfördes semistrukturerade intervjuer med representanter från Fortum, Sydkraft Sverige (Uniper) och Kärnfull Next. Samtliga företag är aktiva inom kärnkraft i Sverige. Arbetet visar att aktörerna ser de största fördelarna med SMR som dess modularitet, relativt låga investeringskrav samt dess friare placering, vilket möjliggör mer effektiv användande. Däremot anser de att utvecklingen av SMR kraftigt begränsas av dagens lagstiftning och licensieringsprocesser. Dessa är designade för att främja begränsning och avveckling av konventionell kärnkraft och enligt respondenterna omöjliggör det framgångsrik utveckling av SMR. Konsekvensen blir att den är mer restriktiv mot SMR:er och försvårar möjligheten att utnyttja de fördelar SMR har gentemot konventionell kärnkraft. Vidare anser respondenterna att det råder en kompetensbrist inom kärnkraft vilket kommer behöva hanteras för att framgångsrikt utveckla SMR i Sverige.

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