Internal gravity waves (GWs) are an important component of the atmospheric dynamics, significantly affecting the middle atmosphere by momentum and energy transport and deposition. In order to be able to improve global circulation models, in which the majority of the GW spectrum is not resolved, it is necessary to quantify their effects as precise as possible. We study GWs in a high-resolution simulation of the WRF model around Southern Andes, Antarctic Peninsula and South Georgia Island. We analyse a Gaussian high-pass filter method for separation of GWs from the basic flow. To overcome an observed problem of dependence of the method on a cutoff parameter, we propose an improved method that determines the parameter at each time step from the horizontal kinetic energy spectrum. The differences between the methods are further examined using the horizontal kinetic energy spectrum, vertical potential energy spectrum and forcing to the divergence equation evaluated by the active wind method, which is a recent theory-based method that divides the flow into a balanced flow and a perturbation field. The results suggest that the high-pass filter method does not produce correct results for time periods with strong wave activity.

No description available.

Au cours des dix dernières années, des composés oligomères intéressants à base de l’acide cholique ont été synthétisés et caractérisés par nos collaborateurs du groupe de Julian X.X. Zhu à l’Université de Montréal (UdeM). Dans un travail récent, ils ont synthétisé un dimère d'acide cholique qui pouvait former de façon réversible une cavité moléculaire lorsqu'il était dissous dans des milieux de polarité différente ; dans l'eau, le dimère forme une cavité hydrophobe, et dans des milieux organiques, le dimère forme une cavité hydrophile. Ainsi, ce type de composés amphiphiles, lorsqu'ils sont en solution, démontre un comportement de cavité moléculaire qui dépend des conditions du solvant, formant une cavité de polarité opposée à celle du milieu dans lequel ils se trouvent. Le comportement d'inversion de la cavité résulte de la flexibilité conformationnelle du lieur chimique entre les monomères d'acide cholique. La capacité des cavités de piéger des sondes moléculaires en fonction de leur polarité suggère que ce type d’oligomères d’acide cholique pourrait constituer des phases stationnaires intéressantes pour la chromatographie en phase liquide à haute performance (HPLC), où la séparation est basée sur la polarité du soluté par rapport à la phase mobile. Puisqu’ils peuvent constituer des cavités hydrophobes et hydrophiles, ils pourraient donc être exploités en chromatographie en phase normale (NPC) et en chromatographie en phase inverse (RPC). La possibilité d'avoir une phase stationnaire réversible avec une affinité bimodale appropriée pourrait être avantageuse en biosciences, en sciences de l'environnement et favoriser la séparation de mélanges complexes en élargissant le champ d'application d’une seule colonne chromatographique. L’affinité bimodale pourrait notamment permettre d'éviter de changer le mode de fonctionnement du HPLC; un processus long, coûteux et nécessitant une grande quantité de solvant pour rééquilibrer et passiver le système fluidique de l’instrument. Ce mémoire est une étude exploratoire qui vise à déterminer si ce type d’oligomères d’acide cholique, une fois liés à des particules de gel de silice (6 μm de diamètre), montre la formation de cavités moléculaires dans diverses conditions de phase mobile et s’il pourrait être utilisé pour effectuer des séparations comme phase stationnaire bimodale. À notre connaissance, il n’existe pas encore de phase stationnaire réversible à base d’oligomères d’acide cholique capables d’interagir avec des composés hydrophiles et hydrophobes, en fonction de la polarité ii de l’éluant. Ce type de phase stationnaire se compare à d’autres phases stationnaires bimodales pouvant être utilisées en NPC ou en RPC, parmi lesquels on trouve entre autres des copolymères amphiphiles, des structures organométalliques et des macromolécules comme les cyclodextrines (CD). La nature bimodale de la phase stationnaire à base de CD rapporté dans la littérature est assez similaire aux phases stationnaires des oligomères d’acide cholique de cette étude, grâce à leur cavité hydrophobe naturelle et un extérieur hydrophile, mais sans toutefois que la cavité soit réversible à cause de la rigidité de l’anneau CD. Les particules de silice greffées avec des oligomères d’acide cholique ont été empaquetées par suspension dans un tube capillaire en silice fondue de diamètre intérieur (ID) de 250 μm pour former des colonnes capillaires de 10 cm de long. Les performances chromatographiques en phase liquide des phases stationnaires ont été étudiées à l'aide d'un instrument HPLC adapté aux colonnes capillaires et muni d’un détecteur d’absorption. Plusieurs sondes-analytes sont étudiées dans ce mémoire pour caractériser la rétention causée par les phases stationnaires dans diverses phases mobiles eau/organique. Des comportements en RPC et d'interaction hydrophile (HILIC) ont été observés dans différentes plages de composition de phase mobile eau/organique. Les tests ont montré que les matériaux étaient capables de retarder des analytes non polaires avec une diminution du pourcentage organique (% org) sur une large plage de compositions (45% à 0% org dans le cas des alkylbenzènes). Les cavités hydrophobes semblent quant à elles être responsables de la rétention aux % org moins que 10% et pour seulement une faible partie de la plage totale de la rétention hydrophobique. Le comportement en phase inverse a été comparé aux colonnes classiques à base de chaînes alkyles (C3, C4, C8 et C18) pour évaluer l’importance des interactions hydrophobes. Inversement, une augmentation du % org, en particulier de l'acétonitrile, a entraîné la rétention de composés polaires sur une courte plage de composition de solvant à partir de 85% org. Cette dernière rétention est toutefois principalement imputable aux mécanismes HILIC avec le support de silice gel découvert et non aux cavités hydrophiles du dimère d’acide cholique. / Over the past ten years, interesting oligomeric compounds based on cholic acids have been synthesized and characterized by our collaborators from the Julian X.X Zhu group at the Université de Montréal (UdeM). In a recent work, they synthesized a cholic acid dimer and showed that it could form invertible molecular pockets when dissolved in media of different polarity; in water, the dimer forms hydrophobic pockets, and in organic media, the dimer forms hydrophilic pockets. Therefore, these amphiphilic compounds, when in solution, demonstrate molecular pocket behavior depending on solvent conditions to form a cavity of opposite polarity of the media in which they are located. The inversion behavior results from the conformational flexibility of the chemical linker between the bile acid monomers. The ability of the pockets to trap probe species based on their polarity suggests that the cholic acid oligomers might be interesting stationary phases for high-performance liquid chromatography (HPLC), where separation is based on solute polarity relative to the mobile phase. Since these materials can produce hydrophobic and hydrophilic pockets, they could be exploited in both normal-phase chromatography (NPC) and reversed-phase chromatography (RPC). The ability to have an invertible stationary phase with suitable bimodal affinity could be advantageous in biosciences, environmental sciences, and for the separation of complex mixtures by widening the field of application of the same chromatographic column. The bimodal affinity may, in particular, make it possible to avoid changing the operating mode of the HPLC; a costly and lengthy process requiring a large amount of solvent to re-equilibrate and passivate all fluidic paths of the instrument. This memoir is an exploratory study that sets out to evaluate whether this type of cholic acid oligomer, once bonded to silica gel particles (6 μm diameter), shows the formation of molecular pockets in various mobile phase conditions and if they can be used to perform separations as bimodal stationary phases. To the best of our knowledge, invertible stationary phases based on cholic acid oligomers that are capable of selective binding and release of both hydrophilic and hydrophobic compounds depending on the polarity of the eluent do not yet exist. This type of stationary phase can be compared to the other bimodal stationary phases that can be used in either NPC or RPC that includes amphiphilic copolymers, organometallic structures and macromolecules like cyclodextrins (CD). The bimodal nature of the CD-based iv stationary phases are quite similar to the cholic acid oligomers stationary phases of this study, thanks to a natural hydrophobic cavity and a hydrophilic exterior, but without the invertibility of the cavity due to the rigidity of the CD ring. The grafted particles were slurry-packed into 250 μm inner diameter (ID) fused silica tubing to make 10 cm long capillary columns. The liquid chromatographic performance of the stationary phases was investigated using a capillary HPLC instrument with a UV absorbance detector. Several probe analytes were investigated to characterize the molecular pocket-based retention in various water/organic mobile phases. RPC and hydrophilic interaction (HILIC) behaviors were observed in distinctive composition ranges of water/organic mobile phases. The tests showed that the materials were able to retain nonpolar compounds gradually with the decrease of percentage organic (% org) over a wide range of compositions (45% to 0% org for alkylbenzenes). The hydrophobic pockets seem to be responsible for the retention at % org less than 10% and only for a small extent of the total range of the hydrophobic retention. The reversed phase behavior was compared to classical alkyl-chain-based columns (C3, C4, C8 and C18) to assess the importance of the hydrophobic interactions. Conversely, an increase in % org, especially acetonitrile, resulted in the retention of polar compounds over a smaller range of % org starting at 85% org. This latter retention is mainly attributable to HILIC mechanisms with the uncapped silica gel support and not the cholic acid dimer hydrophilic pockets.

Ce travail vise à améliorer la compréhension des signaux sismiques dérivés des fonctions de corrélation inter-récepteur du bruit sismique, ce qui est critique pour une imagerie fiable de la Terre profonde basée sur le bruit. La thèse comprend sept chapitres. Le chapitre 1 introduit les connaissances de base sur le bruit sismique, de la terminologie à ses origines diverses. Le chapitre 2 fournit une vue d'ensemble de la littérature sur l'historique et le développement de la méthode récente de corrélation de bruit, et passe en revue diverses techniques pour le prétraitement des données de bruit sismique et le post-traitement des fonctions de corrélation de bruit. Des méthodes de traitement du bruit basées sur les statistiques et un schéma modifié pour calculer la fonction de corrélation sont développés dans ce chapitre. Le chapitre 3 propose plusieurs techniques basées sur la transformée de Radon pour mesurer les lenteurs des champs d'ondes corrélés et analyser en termes de phases sismiques les signaux dérivés du bruit. Le chapitre 4 montre que les ondes de volume sondant la Terre profonde peuvent être extraites des corrélations de bruit à des distances télésismiques, avec des enregistrements de bruit provenant de deux réseaux sismiques régionaux. Le chapitre 5 applique les techniques proposées au chapitre 3 aux corrélations de bruit entre deux réseaux calculées au chapitre 4, et permet de comprendre l’origine de la phase précoce non-physique observée dans les données. Le chapitre 6 discute des conditions dans lesquelles apparaissent des phases sans correspondance dans la réponse physique de la Terre qui peuvent fausser les analyses des structures profondes basées sur le bruit.. Le dernier chapitre fournit un résumé sur les contributions de cette thèse et une perspective de plusieurs travaux soit en cours soit envisagés pour le futur. / This work aims toward an improved understanding of the seismic signals derived from the inter-receiver correlation functions of seismic noise, which is valuable and critical for a reliable noise-based deep Earth imaging. The thesis consists of seven chapters. Chapter 1 introduces background knowledge on seismic noise, from its classifications to various origins. Chapter 2 provides a literature overview on the history and development of the emerging noise correlation method, and reviews various techniques for the pre-processing of seismic noise data and post-processing of noise correlation functions. Statistics-based noise processing methods and a modified scheme for computing correlation function are developed in this chapter. Chapter 3 proposes several Radon-based techniques to analyze the slownesses of correlated wavefields and to unveil the origin of noise-derived seismic signals. Chapter 4 shows that body waves penetrating into deep Earth can be extracted from noise correlations at teleseismic distances, with noise records from two regional seismic networks. Chapter 5 applies the techniques proposed in chapter 3 to the double-array nose correlations computed in chapter 4, and accordingly reveals the origin of an early spurious phase observed in chapter 4. Chapter 6 discusses several situations that bring ambiguities into the noise-derived seismic signals and can potentially bias the noise-based imaging of subsurface structure. The last chapter provides a summarization over the contributions of this thesis and an outlook of several ongoing and prospected works.

Standards apply the proof of competence method to prove that a design force does not exceed a certain limit to ensure a certain safety level. Furthermore, standards elaborated during the last years apply a cycle-based approach instead of a time-based approach. The shortcomings of the standard ISO 16625:2013 need to be addressed in a revision. Therefore, the working group WG3 of ISO/TC 96 SC3 is preparing a new working draft ISO/WD 16625. This presentation is showing the requirements and objectives.

The main goal of this research is to quantitatively assess the resilience and vulnerability of geotechnical infrastructure to extreme events under a changing climate. In the first part, pertinent facts and statistics regarding California’s extreme drought and current status of its levees are presented. Weakening processes such as soil strength reduction, soil desiccation cracking, land subsidence and surface erosion, and oxidation of soil organic carbon are comprehensively evaluated to illustrate the devastating impacts that the California drought can have on earthen structures. In the second part, rainfall-triggered slope instabilities are analyzed using extreme precipitation estimates, derived using the historical stationary and a proposed future nonstationary approach. The extremes are integrated into a series of fully coupled 2D finite element simulations. The final part of this study investigates the impact of simultaneous variations in soil moisture and temperature changes in the California region on soil strength through a proposed thermo-hydro-mechanical framework.

The global energy system is under transformation. The energy transition from a centralized, fossil fuel based energy system to a more decentralized, renewable energy based system will challenge the balancing of electricity supply and demand. This stresses the importance of grid flexibility. In this challenge, energy storage will play a valuable role as it can provide flexibility and support the renewable energy integration. More specifically, lithium-ion battery energy storage systems (Li-ion BESS) demonstrate technological advantages and valuable application possibilities in the electricity grid. This thesis examines opportunities and barriers for deployment of grid-scale Li-ion BESS in the Swedish electricity market, and provides an overview of different perspectives of possibilities with BESS from several market actors. The purpose of the exploratory study is to gain an understanding of prospects for grid-scale BESS in Sweden. Through a comprehensive literature study and an empirical study, based on fourteen interviews with various actors in the electricity market, data was collected and analyzed. The analysis of the empirical findings resulted in two tables summarizing opportunities and barriers for implementation of BESS in Sweden. The opportunities and barriers are categorized into three hierarchical levels; contextual level, power system level and BESS level, referring to where in the system the benefits or hinders are localized. Also, key discussion points related to BESS (such as storage time perspective, ownership, grid services, cost, price signals and knowledge gap) are explored and evaluated. Furthermore, to understand the possibilities for grid-scale BESS in Sweden, a potential business setup for BESS is assessed and analyzed to identify preconditions for BESS to be attractive on the Swedish electricity market. The findings of the thesis indicate that grid flexibility is most likely going to be a considerable issue within 10-20 years. By the time of the potential nuclear phase out in Sweden, there will be major instabilities in the electricity grid if solutions are not in place. Therefore, keys to grid flexibility need to be evaluated and planned for well in advance, and the findings indicate that BESS could be a possible part of the solution. Until now, the regulatory framework has been perceived as rather unclear when it comes to energy storage, which has led to uncertainties among the market actors. These unclarities are about to be clarified with new laws and regulations, which will enable potential businesses for BESS. With the changes in the regulatory framework in place, we see an opportunity with new actors on the market. Our analysis shows that the BESS owner will most likely be a commercial actor, to enable utilization of a BESS for combined applications. An important factor, affecting the possibilities of implementing BESS on the Swedish electricity market, is the cost of BESS. We consider the cost aspect as vital for the likelihood of deploying BESS in Sweden. Based on our main findings, we conclude several preconditions for the deployment of BESS in Sweden. These are; decreased costs of BESS, acceptance from market actors, increased knowledge, a trading platform for grid services provided by a BESS, coordination between markets and electricity load forecasts. We believe that if these preconditions are fulfilled, Li-ion BESS has a chance to affect and have an impact on the Swedish electricity market. / Dagens energisystem är under förändring. Det sker en omvandling där energisystemet går från att vara centraliserat och fossilbaserat till att bli mer decentraliserat och baserat på förnybar energi. Detta kommer att utmana balanseringen av elproduktion och elkonsumtion, vilket betonar vikten av flexibilitet i elnätet. I den stundande utmaningen kommer energilagring att spela en viktig roll eftersom det kan bidra med flexibilitet och samtidigt stödja integrationen av mer förnybar elproduktion. Mer specifikt har energilagersystem med litiumjon-batterier flertalet tekniska fördelar och värdefulla användningsområden i elnätet. Det här examensarbetet utforskar möjligheter och hinder för en framtida implementering av nätanslutna litiumjonbatterilager på den svenska elmarknaden och ger en överblick över perspektiv på utsikter för batterilager från flertalet marknadsaktörer. Syftet med den utforskande studien är att få en ökad förståelse för framtidsutsikterna för storskaliga batterilager i Sverige. Genom en omfattande litteraturstudie och en empirisk studie, baserad på fjorton intervjuer med olika aktörer på elmarknaden, samlades data in och analyserades. Analysen av de empiriska resultaten resulterade i två tabeller som sammanfattar möjligheter och hinder för implementering av batterilager i Sverige. Möjligheterna och hindren kategoriseras i tre hierarkiska nivåer; kontextuell nivå, kraftsystemnivå och batterilagersystemnivå, med hänvisning till var i systemet fördelarna eller barriärerna är lokaliserade. Dessutom utvärderas flera betydande diskussionsteman relaterade till batterilager (såsom lagringstid, ägande, nättjänster, kostnad, prissignaler och kunskapsluckor). För att förstå möjligheterna för att etablera batterilager i Sverige har en möjlig affärsuppställning utvärderats och analyserats. Detta för att identifiera förutsättningar för att batterilager ska vara attraktivt på den svenska elmarknaden. Examensarbetets resultat tyder på att nätflexibilitet sannolikt kommer att bli ett betydande problem inom 10-20 år. Den troliga avvecklingen av den svenska kärnkraften kommer att resultera i instabilitet i elnätet om inte lösningar finns på plats. Därför behöver lösningar för att uppnå flexibilitet i elnätet utvärderas och planeras i god tid och uppsatsens resultat visar på att batterilager kan vara en möjlig del av lösningen. Fram till nu har det funnits oklarheter i regelverket gällande energilagring, vilket har lett till osäkerheter hos marknadsaktörerna. Nya lagar och förordningar kommer att klargöra flertalet osäkerheter och möjliggöra potentiella affärer med batterilager. När det förändrade regelverket är på plats, ser vi potential för nya aktörer på marknaden. Vår analys visar på att batterilager med största sannolikhet kommer att ägas av kommersiella aktörer för att möjliggöra kombinerade användningsområden av batterilager. Möjligheterna till implementering av batterilager på den svenska elmarknaden påverkas i hög grad av kostnaden för batterilager. Vi anser att kostnadsaspekten är avgörande för sannolikheten att utnyttja batterilager i Sverige. Vår slutsats är att det finns flertalet förutsättningar för att batterilager ska bli attraktivt och lönsamt i Sverige. Dessa är; minskade kostnader för batterilager, acceptans från marknadsaktörer, ökad kunskap, en handelsplattform för nättjänster som tillhandahålls av batterilager, samordning mellan marknader samt lastprognoser. Om dessa förutsättningar uppnås anser vi att litiumjon-batterilager har en chans att påverka den svenska elmarknaden.

No description available.

Raman spectroscopy, laser-induced fluorescence, and sum-frequency generation (SFG) spectroscopy are used to investigate the behavior of compressible mobile phases and stationary phases under a variety of chromatographic conditions. Efforts to understand and optimize separations employing compressible mobile phases have been limited by a lack of understanding of the mobile phase density gradient. Mobile phase compressibility leads to gradients in linear velocity and solute retention and affects separation speed and efficiency, especially in packed columns. This work describes on-column density measurement of CO2, a common carrier fluid for SFC and SGC, in packed capillary columns using Raman microspectroscopy. On-column detection by laser-induced fluorescence is used to observe the effect of the mobile phase density gradient on separation speed and efficiency, and experimental efficiency is compared to a theoretical model. Additionally, SFG spectroscopy allows for probing the structure of model monomeric and polymeric C18 stationary phases under pressure; this provides a basis for correlating selectivity with pressure-induced structural changes in stationary phase materials. Together, this work provides a more complete understanding of the role of column pressure and fluid compressibility on the speed, efficiency, and selectivity of chemical separations.

Breast Cancer is the second most common cancer in Sweden. More treatment options are available with a higher chance of survival if Breast cancer is diagnosed early. WHO has recommended performing Breast Cancer screenings on women even before they develop any symptoms. In Sweden, all women between the age of 40 and 74 years are called for a Breast Cancer Screening examination every two years. However, all of the called out women are not appearing for Breast screening therefore the purpose of this degree project is to analyze the possible benefits of setting up Mobile Mammography Units (MMUs) in Sweden. This thesis focuses on need-analysis, cost-analysis, image quality, and quality of care in MMUs compared to fixed units and if MMUs can be used as a tool for dispersal of knowledge regarding preventive care for cancer. Further, long waiting queues is one of the major concern and underperformed area in Sweden. Since the enactment of Cancer Care Pathways in Sweden, long waiting queues for patients having non-cancer diseases have been the most frequently mentioned risk in the regional status reports. This study, therefore, aims to analyze if mammography screening in hospitals is adding up to the long waiting ques for other patients or not. This study followed a qualitative setting where several semi-structured interviews were conducted with members of the National workgroup of mammography in Sweden, and an abductive inductive approach was followed for the data collection and analysis. The results of the study concluded that Mobile mammography units are only beneficial for areas with demographic issues. Mobile mammography units are resource-demanding therefore it is better to invest in fixed units for areas where there are no traveling issues. The mammography unit in a hospital is a separate department and does not affect any other patient by being in the hospital hence not resulting in the “Crowding out effect”. Regarding the Image quality and quality of care, it is similar in both the fixed and mobile units, apart from the quality of care for disabled women who must visit the fixed unit and hence are deprived of close care. A proper cost-analysis, with exact figures, for both mobile and fixed mammography units was not found during this study therefore it could not be concluded if MMUs are cost-effective or not. Also, if Mobile Mammography Units are to be used as a tool for the dispersal of knowledge regarding the prevention of cancer, there will be a need to hire extra staff who can perform this job. / Bröstcancer är den näst vanligaste cancerformen i Sverige. Fler behandlingsalternativ finns tillgängliga med högre chans att överleva om bröstcancer diagnostiseras tidigt. WHO har rekommenderat att utföra bröstcancerscreeningar på kvinnor även innan de utvecklar några symtom. I Sverige kallas alla kvinnor mellan 40 och 74 år till en bröstcancerundersökning vartannat år. Alla kvinnor som bjuds in till undersökning dyker dock inte upp, därför är syftet med detta examensarbete att analysera möjliga fördelar med att sätta upp mobila mammografienheter (MMU) i Sverige. Långa väntetider är ett stort problem i Sverige, även för dessa patienter som inte har cancer eller tecken på cancer. Denna studie syftar därför till att analysera om mammografiscreening på sjukhus ökar eller minskar de långa väntetiderna för andra patienter som inte är drabbade av cancern. Resultat av studien visar att mobila mammografienheter endast är fördelaktiga för områden med demografiska problem. Mobila mammografienheter är resurskrävande, därför är det bättre att investera i fasta enheter för områden där det inte finns några reseproblem. Också Mammografienheten på ett sjukhus är en separat avdelning och bör inte påverka antal mängder patienter på ett sjukhus. Vi kunde inte fastställa kostnader för vare sig mobila eller fasta mammografienheter under denna studie. Därmed kan slutsatsen inte avgöras om det är förmånligt med mobila mammografienheter eller inte. Men däremot är en sak säker, det kommer att behövas att anställa fler personal.