<p>To be able to ensure quality, efficiency and safety in nuclear reactors, non-destructive evaluations (NDE) are performed. The moulding technique, which has been studied in this project, is an NDE method used to verify surface breaking cracks at various objects in reactor vessels.</p><p>The idea of moulding is to receive a copy of the replicated surface for microscopic analysis. Within forensic science the moulding technique is used at crime scenes to collect evidence and tie suspects to crimes. Underwater moulding, however, is a newly developed technique and WesDyne TRC is a pioneer in offering services within moulding for underwater purposes.</p><p>This project was initiated by WesDyne TRC to further their knowledge within the moulding technology. In the project, studies have been made at three important parameters effect on cast quality using three different polymer compounds. Problems during moulding, such as crack detection failures and bubbles in the casts, raise the question whether the underwater moulding technique can be trusted to detect cracks.</p><p>Results from the experiments led to a greater insight into the problem with receiving high quality casts during underwater moulding. Only if a satisfactory cast is made, the moulding method can be trusted to detect defects down to the detection target in both dry and wet environment.</p><p>To increase the surface quality of underwater casts a suggestion for mould design and a recommended moulding method was developed. In addition, one of the polymer compounds approved for use, turned out not to be suitable for underwater moulding.</p>

<p>There is a need for reliable valves and pumps in microfluidics. A good microactuator is the key for low cost and high performance of these components.</p><p>Paraffin wax is a promising material to be used as actuator material as is can produce large forces and large strokes. Further, the material is inexpensive and, none the less, the thermal heating of the material can be made with low voltages. All these properties are of interest in flow control components in microfluidics, and especially for disposables and in potable systems.</p><p>In this work, paraffin wax has been used in devices and concepts. A valve for high-pressures, a peristaltic pump, a multi-stable actuator, and injector has been shown. A material study was performed on binary mixtures of pure paraffin (n-alkanes), and a concept for loading fluid into a sealed reservoir was shown as well. Several injectors were demonstrated in a Lab-on-a-chip system with other microfluidic components.</p><p>High pressure applications in microfluidics along with the multi-stable actuator show good potential. However, the drive and control has to be further developed.</p>

The main objective of this thesis is to use available knowledge about a process and combine this with measurement data from the same process to extract more information about the process. The combination of knowledge and measurement data is referred to as Multi Sensor Data Fusion, MSDF. This added information is then used to control the process towards a specified goal. The process studied in this thesis is the process of drilling wells in a petroleum reservoir, while the oil is flowing from the reservoir. In the petroleum industry, this is defined as underbalanced drilling (UBD), where the bottom hole pressure (BHP) in the well is below the pore pressure in the reservoir. Detailed knowledge of the process is of paramount importance when using multi sensor data fusion. Due to this, various process modelling efforts are examined and evaluated, from simple relations between parameters to a finite-element approach of modelling the fluid flow in the well during drilling. Several sensors are used in the various cases, and existing sensors such as pressure sensors and flow sensors are the main data source in the analysis. Future scenario with sensors such as pressure arrays and non-intrusive multiphase flow meters are evaluated. In addition, new positions of existing sensor systems are discussed. The methods available for fusing the knowledge of the process represented as models together with the available data is ranging from artificial intelligent methods such as neural networks, to methods incorporating statistical analysis such as various Kalman filters. History matching techniques using gradient techniques are also examined. The migration of reservoir fluids into the well during UBD influences the BHP of the well. The results in the thesis show that this reservoir influx can be calculated by estimating some of the important reservoir parameters such as reservoir pore pressure or reservoir permeability. These reservoir parameters can be estimated most efficiently by performing an MSDF using a detailed nonlinear model of the well and reservoir dynamic behaviour together with real-time measurements of the fluid flow parameters such as fluid temperature, fluid pressure and fluid flow rates. The unscented Kalman filter shows the best performance when evaluating both estimation accuracy and computational requirements. Regarding available instrumentation for use during UBD, the analysis shows that there is a major potential in introducing new sensors. As new data transmission methods are emerging and making data from sensors distributed along the drillstring available, this can generate a shift in paradigm regarding real-time analysis of reservoir properties during drilling. Controlling the process is an important usage of the information gained from the MSDF analysis. Various control methods for controlling the most important process variables are examined and evaluated. The results show that acceptable pressure control can be obtained when using the choke valve opening as the primary control parameter. However, the choke valve operation has to be closely coordinated with drilling fluid flow rate adjustments. The choke valve opening control is able to compensate for pressure variations during the whole drilling operation. A suggested nonlinear model predictive control algorithm gives best results when looking at the control accuracy, and can easily be expanded to handle multiple control inputs and system constraints. This control algorithm uses a detailed model of the well and reservoir dynamics. The Levenberg-Marquardt algorithm is used to calculate the optimal future control variables. The main drawback of the control algorithm is computational burden. A linear control algorithm, which also is evaluated, uses less computational resources, but has less control accuracy and is more difficult to expand into a multivariable control system. Recommendations for further work are to expand the suggested model predictive control algorithm to handle more control inputs, while reducing the computational burden by incorporating low-order models for describing the future behaviour of the well.

There is a need for reliable valves and pumps in microfluidics. A good microactuator is the key for low cost and high performance of these components. Paraffin wax is a promising material to be used as actuator material as is can produce large forces and large strokes. Further, the material is inexpensive and, none the less, the thermal heating of the material can be made with low voltages. All these properties are of interest in flow control components in microfluidics, and especially for disposables and in potable systems. In this work, paraffin wax has been used in devices and concepts. A valve for high-pressures, a peristaltic pump, a multi-stable actuator, and injector has been shown. A material study was performed on binary mixtures of pure paraffin (n-alkanes), and a concept for loading fluid into a sealed reservoir was shown as well. Several injectors were demonstrated in a Lab-on-a-chip system with other microfluidic components. High pressure applications in microfluidics along with the multi-stable actuator show good potential. However, the drive and control has to be further developed.

Localization and magnetic properties of electrons in a thin, cyclic quasi one-dimensional GaAs wire with a central potential barrier were studied using the Hartree-Fock and LSDA (Local Spin Density Approximation, exchange only) and compared to more time consuming Quantum Monte-Carlo calculations. Within LSDA, evidence of true localization was found as well as evidence for the existence of both ferromagnetic as well as anti-ferromagnetic states. Also signs of two-dimensional spin localization was found, without associated localized electrons.

This master thesis was carried out at the Department of Aerodynamics and Flight Mechanics at Saab Aerosystems, Linköping, Sweden. It makes up the author’s final work prior to graduation in the field Applied Physics and Electrical Engineering at the Department of Electrical Engineering at The Linköping Institute of Technology (LiTH), Linköping, Sweden.   The objective of the paper was to study a non-uniform helicopter rotor downwash model in forward flight for the unmanned helicopter Skeldar, which is under development at Saab. The main task was to compare the mentioned model with today’s uniform downwash model in order to find differences and similarities. This was done both from a modeling and a controlling perspective. To start with, an introduction is given which is followed by a helicopter theory chapter. The following three chapters deal with the theory of induced velocity, the helicopter model and the Linear Quadratic Regulator (LQR). Finally, the results are presented and discussed.   The downwash models were derived using Momentum Theory (MT) and Blade Element Theory (BET). These two theories were combined in order to find a connection between the induced velocity and the rotor thrust coefficient. The non-uniform downwash model that was studied is proposed by Pitt &amp; Peters and describes a linear variation of the induced velocity in the longitudinal plane.   For the control, a LQ-regulator was chosen since it is easily implemented in MATLAB and it stabilizes the plant model by feedback and consequently creates a robust system. Before the controller could be implemented, the models had to be reduced and the states had to be divided into longitudinal and lateral ones.   The comparison between the open systems clearly shows that differences in the inflow models propagate to all states and consequently the helicopter behaves differently in all planes. Great discrepancies are apparent for the angular velocities p and q. For Pitt &amp; Peters’ model those states are believed to be strongly affected by the system’s positive real pole, causing a rather unstable behavior. When the systems were closed by feedback, the differences were reduced dramatically. Pitt &amp; Peters’ model resulted in greater overshoots than the uniform model, but the overall behavior of all states was rather similar for the two models.   It is concluded, that the adaption of Pitt &amp; Peters’ inflow model does not make any substantial difference when a controller is implemented. The differences between the open systems, however, are reason enough to question Pitt &amp; Peters’ model. In order to evaluate the non-uniform model properly, it has to be compared to suitable flight data which is still lacking up to this date.

To be able to ensure quality, efficiency and safety in nuclear reactors, non-destructive evaluations (NDE) are performed. The moulding technique, which has been studied in this project, is an NDE method used to verify surface breaking cracks at various objects in reactor vessels. The idea of moulding is to receive a copy of the replicated surface for microscopic analysis. Within forensic science the moulding technique is used at crime scenes to collect evidence and tie suspects to crimes. Underwater moulding, however, is a newly developed technique and WesDyne TRC is a pioneer in offering services within moulding for underwater purposes. This project was initiated by WesDyne TRC to further their knowledge within the moulding technology. In the project, studies have been made at three important parameters effect on cast quality using three different polymer compounds. Problems during moulding, such as crack detection failures and bubbles in the casts, raise the question whether the underwater moulding technique can be trusted to detect cracks. Results from the experiments led to a greater insight into the problem with receiving high quality casts during underwater moulding. Only if a satisfactory cast is made, the moulding method can be trusted to detect defects down to the detection target in both dry and wet environment. To increase the surface quality of underwater casts a suggestion for mould design and a recommended moulding method was developed. In addition, one of the polymer compounds approved for use, turned out not to be suitable for underwater moulding.

This study is concerned with the negative effects of wearing corrective lenses while using eye trackers, and the correction of those negative effects. The eye tracker technology studied is the video based real-time Pupil Center and Corneal Reflection method. With a user study, the wearing of eyeglasses is shown to cause 20 % greater errors in the accuracy of an eye tracker than when not wearing glasses. The error is shown to depend on where on the eye tracker viewing area the user is looking. A model for ray refraction when wearing glasses was developed. Measurements on distortions on the image of the eye caused by eyeglass lenses were carried out. The distortions were analyzed with eye tracking software to determine their impact on the image-to-world coordinates mapping. A typical dependence of 1 mm relative distance change on cornea to 9 degrees of visual field was found. The developed mathematical/physiological model for eyeglasses focuses on artifacts not possible to accommodate for with existing calibration methods, primarily varying combinations of viewing angles and head rotations. The main unknown in the presented model is the effective strength of the glasses. Automatic identification is discussed. The model presented here is general in nature and needs to be developed further in order to be a part of a specific application.

This report treats detection in IR-pictures taken from airplanes over the ground. The detection is divided in two parts. First there is a detection with filterkernels with the task to point on targets and objects that look like targets. The second part is a discriminator that demands more calculations and has the task to sort out the false alarms from the discriminator. Both the detector and the discriminator contain thresholds thats been trained from trainingsets of data. The results from the detector was better then expected hence it wasn’t possible to test the diskriminator properly. / Den här rapporten behandlar detektering i IR-bilder som är tagna från flygplan över marken. Detekteringen är i det här arbetet uppdelat i två delar. Först görs en detektering med filterkärnor som har till uppgift att peka ut mål och målliknande objekt. Den andra delen är en diskriminator som är något mer beräkningskrävande och har till uppgift att sortera bort de falskmål som detektorn fått med. Både detektorn och diskriminatorn innehåller trösklar som har tränats fram med träningsdata. Detektorn gav bättre resultat än väntat och diskriminatorn har därför inte kunnat testas ordentligt.

Saturn’s largest moon, Titan, presents a very interesting subject for study because of its atmosphere’s complex organic chemistry. Processes taking place there might shed some light on the origins of organic compounds on Earth in its early days. The international spacecraft Cassini-Huygens was launched to Saturn in 1997 for a detailed study of the gas giant and its moons, specifically Titan. The Swedish Institute of Space Physics in Uppsala has manufactured the Langmuir probe instrument for the Cassini spacecraft now orbiting Saturn, and is responsible for its operation and data analysis. This project concerns the analysis of Titan’s ionosphere measurements from this instrument, from all “deep” flybys of the moon (&lt;1400km altitude) in the period October 2004 - April 2010. Using the Langmuir Probe analysis tools, the ion flux is derived by compensating for the atmospheric EUV extinction (that varies with the photoelectron current from the probe). The photoelectron current emitted from the probe also gives an artifact in the data that for this project needs to be deducted before analysis. This factor has already been modeled, while the extinction of Titan’s atmosphere has only been taken into account on event basis (not systematically). The EUV corrected ion flux data is then used to derive the ion number density in Titan’s atmosphere, by setting up an average ion mass altitude distribution (using the Ion Neutral Mass Spectrometer results for comparison) and deriving the spacecraft speed along the Cassini spacecraft trajectory through Titan’s ionosphere. The ion number density results proved to correlate very well with the theoretical ionospheric profiles on the day side of Titan (see graphical representation in the Results section). On the night side, a perturbation of the ion flux data was discovered by comparison with Ion Neutral Mass Spectrometer data, supporting earlier measurements of negative ions reported by Coates et al 2009. The project was carried out at the Swedish Institute of Space Physics (Institutet för Rymdfysik, IRF) in Uppsala. / Saturnus största måne Titan är ett väldigt intressant forskningsobjekt på grund av dess atmosfärs komplexa organiska kemi. Processer som pågår i Titans täta atmosfär kan hjälpa oss att förstå ursprunget till organiska föreningar på Jorden i dess unga ålder. Den internationella rymdsonden Cassini-Huygens blev uppskjuten mot Saturnus 1997, för att i detalj undersöka gasjätten och dess månar, speciellt Titan. Institutet för Rymdfysik (IRF) i Uppsala är ansvariga för operation och dataanalys av Langmuirsonden ombord Cassini som ligger i omloppsbanan kring Saturnus sedan 2004. Detta projekt omfattar analys av Langmuirsondens mätningar av Titans jonosfär från alla ”djupa” förbiflygningar av månen under perioden oktober 2004 – april 2010. Med hjälp av analysverktygen för Langmuirsonden, tas jonflödet fram efter kompensation för den atmosfäriska EUV extinktionen som ger upphov till fotoelektronströmmen från sonden. Fotoelektronströmmen som utsänds från proben ger en artefakt i data och måste (för detta projekt) korrigeras före analysen. Denna faktor är redan bestämd, men extinktionen av Titans atmosfär har endast korrigerats för i enstaka fall. Det korrigerade datat används för att få fram jondensiteten i Titans atmosfär genom att en genomsnittlig jonmass/höjd fördelning antas (jämförs med resultat från INMS-instrumentet) och kombineras med den beräknade hastighet som Cassini håller i banan genom jonosfären. Projektet utfördes vid Institutet för Rymdfysik, Uppsala.