Delar av marken i Uppsala består av mäktiga lerlager. Naturliga krypsättningar pågår ständigt i området, en process som i litteraturen benämns geologisk åldring. Ökad belastning i form av uppfyllnad kring byggnader och sänkt grundvattenyta till följd av pumpning av färskvatten bidrar också till sättningar. I ett nybyggt bostadsområde på Kapellgärdet har marksättningarna intill de pålade husen på vissa platser uppgått till 0.3 m på 10 år. Med geotekniska data för området har en jordprofil tolkats. Analys har gjorts utifrån den klassiska sättningsteorin för primärsättningar till av ökade effektivspänningar från fyllnadsmassor och grundvattensänkning. Krypsättningens storlek har uppskattats utifrån erfarenheter vid ett provfält i Stockholm - Mälardalen med liknande jordlagerföljd och geoteknisk egenskaper. De antaganden som görs i den klassiska sättningsmodellen ger en kraftigt förenklad bild av verkligheten, vilket kan leda till stora avvikelser mot det verkliga utfallet. Modellen som används vid beräkning av portrycksutjämningen stämmer inte med verkligheten för den jordlagerföljd som finns på många håll i Stockholm – Mälardalen. Den undre varviga lerans dränerande egenskaper i horisontell riktning och den snabba uttorkningen i den gyttjiga leran kan bidra till det snabba sättningsförloppet. För att bättre kunna förstå sättningsförloppet krävs noggrannare observationer av portrycksutjämningen genom hela leran. Vidare bör bidraget från krypsättningar beaktas, eftersom dessa verkar utgöra en stor del av den totala sättningen. / Parts of the ground in Uppsala consist of thick clay deposits. Natural creep settlements are ongoing in the area due to a process in the literature named geological aging. Increased load on the ground due to fill and lowered groundwater table due to pumping of drinking water are also contributing to settlements. The ground settlements in a new residential area at Kapellgärdet have in parts of the area reached up to 0.3 m during the first 10 years. With geotechnical data from the area, the soil profile has been interpreted. Calculations have been made based on the classic model for primary consolidation caused by increased effective stress from loading and lowered groundwater table. Contribution from creep has been estimated from experience at a test field in Stockholm – Mälardalen with similar soil profile and geotechnical properties. The assumptions made in the classic model provide a simplified picture of the reality, which may lead to large deviations from the actual outcome. The model used in the calculations of pore pressure equalization does not match the reality of the stratigraphy found in many areas in Stockholm – Mälardalen. The drainage properties of the varved clay and the fast desiccation of the muddy clay are thought to contribute to the fast consolidation process. To better understand the consolidation process, more detailed observations of the pore pressure equalization need to be done through the clay. Furthermore, settlement contribution due to creep is needed, as it seems to be a large part of the total settlements.

Abstract Photovoltaic (PV) solar panels are solar energy collection systems with increasing terrestrial and roof applications reported worldwide. If the terrestrial mounting does not require specific wind resistance verifications, installing them on top of flat and gable roofs implies a drastic change of the roofing systems geometry, thus a re-evaluation of the wind-induced pressure is necessary. Among the roof top applications, provisions exist for the flat roofs mounted solar panels, however, design recommendations for wind-induced loadings on PV solar panels arrays flush-mounted on gable roofs are not fully developed in current wind loading standards (SEAOC PV2-2012) and building codes (ASCE 07, NBCC 2015), in spite of the numerous applications on residential and agricultural buildings, primarily due to the limited research investigating this topic. The current dissertation employs CFD k-ɛ and LE (Large Eddy) simulations for analyzing the effects of wind acting on solar panels flush-mounted on gable roofs, considering the influence of several parameters such as: the slope of the gable roof, the wind directions, the spaces between the adjacent solar panel arrays and the clearance between the roof surface and the solar panels. A comprehensive database of solar panels with different installation parameters subjected to wind speeds were developed under the current research project. The database includes detailed distribution of wind-induced pressure coefficients for the three parallel surfaces constituting the roof-solar panels systems: the top and bottom surfaces of the panels, and the roof surface under the panels, which represents a novel approach in investigating and clarifying the wind effects on solar panels. This approach also provides in detail the variation of the pressure coefficients on the three surfaces, due to the change of installation conditions (roof slope, arrays spacing, roof clearance) and wind parameters (wind speed and wind direction). As an original contribution to the existing knowledge, this thesis found that the installation of solar arrays on gable roofs, redistributes the wind-induced pressure on both sides of the roof windward and leeward, resulting in total horizontal wind-induced pressures on the entire roof lower than that registered on the corresponding roof without solar panels. In addition, dominant resultant pressure coefficients on solar panels concluded to be lower than for the roof without panels. When the roof clearance increases, total average pressure coefficients on the roof supporting the panels decreases on both, windward and leeward sides of the roof. Moreover, when the roof clearance increases, the pressures in the cavity decrease significantly on both windward and leeward sides of the roof, which could impact the requirements for installing and fixing such panels on gable roofs. For example, for 10” clearance the flush-mounted solar panels were subject to pressure instead of suction. Similarly, when panel array spacing increases, the magnitude of the net mean pressure coefficients on the roof surface under the solar panels further decreases for all wind directions investigated.

Sound pressure equalization of audio signals using digital signal processors has been a subject of ongoing study for many years. The traditional approach is to equalize sound at a point in a listening environment, but because of its specific dependence on the room frequency response between a source and receiver position, this equalization generally causes the spectral response to worsen significantly at other locations in the room. This work presents both a time-invariant and a time-varying implementation of an adaptive acoustic energy density equalization filter for a one-dimensional sound field. Energy density equalization addresses the aforementioned challenge and others that relate to sound equalization. The theory and real-time implementation of time-invariant sound pressure and energy density equalizers designed using the least-squares method are presented, and their performances are compared. An implementation of a time-varying energy density equalizer is also presented. Time-invariant equalization results based on real-time measurements in a plane-wave tube are presented. A sound pressure equalizer results in a nearly flat spectral magnitude at the point of equalization. However, it causes the frequencies corresponding to spatial nulls at that point to be undesirably boosted elsewhere in the sound field, where those nulls do not exist at the same frequencies. An energy density equalization filter identifies and compensates for all resonances and other global spectral effects of the tube and loudspeaker. It does not attempt to equalize the spatially varying frequency nulls caused by local pressure nodes at the point of equalization. An implementation of a time-varying energy density equalizer is also presented. This method uses the filtered-x filter update to adjust the filter coefficients in real-time to adapt to changes in the sound field. Convergence of the filter over time is demonstrated as the closed end of the tube is opened, then closed once again. Thus, the research results demonstrate that an acoustic energy density filter can be used to time-adaptively equalize global spectral anomalies of a loudspeaker and a one-dimensional sound field.

La pile à combustible (PàC) est un dispositif qui produit de l'électricité à partir d'une réaction chimique entre l'hydrogène et l'oxygène. Le système à PàC nécessite un certain nombre d'auxiliaires pour fonctionner. Pour cela, un système de commande est indispensable pour optimiser la performance de la PàC.Dans ce travail de thèse, nous nous sommes intéressés à trois types de problématiques de commande de la PàC. La première est celle de l'optimisation de la puissance délivrée par la PàC en contrôlant le rapport d'excès d'oxygène via le débit d'air du compresseur ; en prenant en compte les variations paramétriques, les incertitudes et les perturbations externes. Ce problème est résolu en utilisant la commande non-linéaire par mode glissant d'ordre 2. Deux types d'algorithme sont synthétisés, l'algorithme du mode glissant d'ordre 2 sous-optimal et l'algorithme du Super Twisting adaptatif. Les performances de ces lois de commande ont été validées grâce à un simulateur Hardware In Loop. La deuxième concerne la maximisation de la puissance nette fournie par la pile, tout en maintenant le fonctionnement du compresseur centrifuge dans sa zone nominale et tout en évitant le manque d'oxygène à la cathode, lors des variations rapides de charge. La solution proposée pour résoudre ce problème est un gestionnaire de charge qui consiste en un filtre à coefficient de filtrage ajustable. Deux approches d'ajustement de ce coefficient basées sur la technique de l'Extremum Seeking sont appliquées, comparées et validées expérimentalement. La troisième problématique abordée dans cette thèse est celle de la régulation de la différence de pression entre l'anode et la cathode, lors de variations de charge en présence de variations paramétriques et d'incertitudes. Une solution basée sur un contrôleur multi-variable par mode glissant d'ordre 2 associé à une étude de robustesse est proposée. / The PEM fuel cell is a device which generates electricity from a chemical reaction between hydrogen and oxygen. The PEM fuel cell requires many ancillaries to operate the system. A control system is needed to optimize the performance of the PEMFC. This thesis is focused upon three specific control problems related to PEM fuel cell systems. The first problem is the control of the air (oxygen source) entering in the cathode side of fuel cell. The objective is to regulate the oxygen excess ratio in order to maintain the optimum net power output. This problem has been addressed using nonlinear second order sliding mode controllers, which are robust against parametric uncertainty and external disturbance. The SOSM controllers are based on two algorithms: sub-optimal and adaptive Super Twisting. Their performance is validated through Hardware In Loop simulation. The second problem is to maintain the centrifugal compressor in its operating zone, while avoiding the oxygen starvation in the cathode side during rapid load variations. The proposed solution to this problem is a load governor, which is similar to a variable bandwidth first order linear filter. Two adjustment algorithms have been applied for the bandwidth coefficient, based on the Extremum Seeking technique. Their performance has been validated experimentally. The third problem addressed in this thesis is the regulation of the pressure difference between the anode and the cathode during load variations. The control objective is achieved using second order sliding mode MIMO controller, which has been shown to be robust against parametric uncertainty and external disturbance.

This master´s thesis analyzes an effect of wind load on the ventilated facade claddings. The analysis is performed on the various types of facades, from unventilated to ventilated facades with a different geometrical arrangement of facade shell. The theoretical part describes the basic knowledge about the theory of flow, turbulence modeling, determining an optimal domain, verification of the calculation model and user interface in the ANSYS software. The final part compares the value of the wind load reduction depending on the change of the gap widths and the size of ventilated spaces. The resulting values are obtained by CFD simulations. The thesis includes a design and an assessment of the steel hall construction.