Digital holographic microscopy (DHM) is noninvasive method for obtaining images even from samples with low contrast. Nowadays DHM design makes it possible to illuminate sample by broad light source, halogene lamp. Broad light source is displayed in the front focal plane of condensor in such way, that Köhler illumination is achieved. Each point of the source corresponds to a plane wave in image field of objective, which illuminates the whole field of view, but from different direction. Position of the point determines the direction of illumination. In this reason, the microscope enables so reconstruct not only intensity, but also phase of object wave. New designed and constructed interchangeable pinhole aperture modify broad light illumination by rotation around the optical axis. Aperture is placed eccentrically considering the optical axis of microscope. Incidence of light beam on a sample would be under defined angle. After the reconstruction of taken phase images from individual angles of illumination should be possible to obtain three-dimensional structure of the sample.

The objective of this master´s thesis is to design machines for straightening rods of circular cross section with a diameter of 10 mm to 50 mm, length 6 m to 9 m. Machine concept is as the simplest as possible with a large proportion of welded elements

Nous présentons une étude expérimentale de l’effet d’une rotation d’ensemble sur les écoulements turbulents statistiquement stationnaires. Dans une première expérience, l’écoulement est entretenu à l’aide de générateurs de tourbillons contrarotatifs agissant de manière périodique dans une cuve en rotation remplie d’eau. Des mesures résolues en temps des trois composantes de la vitesse sont réalisées, dans des plans horizontaux et verticaux, à l’aide d’un dispositif de vélocimétrie stéréoscopique par images de particules embarqué dans le référentiel tournant. L’écoulement étudié présente, conformément à la littérature, une forte anisotropie et montre l’émergence d’un mode 2D énergétique. Pour la première fois expérimentalement, nous décrivons le bilan global d’énergie entre échelles d’une turbulence en rotation à travers la mesure des termes de l’équation de Kármán-Howarth-Monin généralisée au cas inhomogène. Nous mettons ainsi en évidence la présence d’une double cascade d’énergie : directe à petite échelle et inverse à grande échelle, l’échelle de renversement des cascades étant décroissante avec le taux de rotation. Nous évaluons ensuite la puissance injectée qui est intrinsèquement liée au caractère inhomogène de l’écoulement. L’injection d’énergie provient de l’auto-advection des structures turbulentes traversant les frontières de la zone de contrôle. Elle est large bande en échelles et s’étale à mesure que la rotation croît. Nous nous intéressons ensuite à la pertinence des modèles de turbulence d’ondes d’inertie. Nous réalisons tout d’abord une analyse spatio-temporelle qui révèle la présence d’ondes d’inertie linéaires à grande échelle spatiale et grande fréquence temporelle. En revanche, nous montrons que la signature spatio-temporelle des structures turbulentes associées aux échelles et fréquences faibles est brouillée par le processus linéaire de balayage stochastique par le mode 2D énergétique. Dans une seconde expérience, l’écoulement est engendré par une hélice constituée de quatre pales rectangulaires dans une cuve fermée en rotation. Nous évaluons le taux de dissipation d’énergie à travers la mesure de la puissance injectée par le moteur qui entraîne l’hélice. Nous fournissons alors, pour la première fois, une preuve directe de la loi d’échelle du taux de dissipation d’énergie prédite par la turbulence d’onde d’inertie qui est diminuée d’un facteur Rossby par rapport à la loi d’échelle de la turbulence 3D homogène et isotrope. / We present an experimental study of the effect of global rotation on statistically stationary turbulent flows. In a first experiment, the flow is generated with counter-rotating vortex generators acting in a periodic motion in a rotating tank filled with water. Resolved in time measurements of the three component of the velocity are performed, in both horizontal and vertical planes, thanks to a stereoscopic particle image velocimetry system embarked in the rotating frame. The flow has, in accordance with the bibliography, a strong anisotropy and shows the emergence of an energetic 2D flow. For the first time experimentally, we describe the global scale by scale energy budget of a rotating turbulence through the measure of the terms of the inhomogeneous generalization of Kármán-Howarth-Monin equation. We thus reveal a double energy cascade: direct at small scale and inverse at large scale, the scale of cascade reversal decreasing with the rotation rate. Then, we evaluate the injected power into the system which is intrinsically linked to the inhomogeneities of the flow. The energy input comes from auto-advection of turbulent structures through the boundaries of the area considered. It is broadband in scales and spreads as ration increases. We then focus on relevance of inertial wave turbulence models. We first perform a spatiotemporal analysis which reveals the presence of linear inertial waves at large frequencies and scales. However, we show that the spatiotemporal signature of small frequencies and scales are scrambled by the linear process of stochastic sweeping by the 2D energetic mode. In a second experiment, the flow is created thanks to a four-rectangular-blade impeller in a closed rotating tank. We estimate the energy dissipation rate through the measure of the injected power by the motor that drives the impeller. We then bring, for the first time, a direct evidence of the scaling law predicted by inertial wave turbulence models which is fallen by a factor Rossby compared to the scaling law of 3D homogeneous isotropic turbulence.

Hydro power plants are an essential part of the infrastructure in Sweden as they stand for a large amount of the produced electricity and are used to regulate supply and demand on the electricity grid. Other renewable energy sources, such as wind and solar power, have become more popular as they contribute to a fossil free society. However, wind and solar power are intermittent energy sources causing the demand for regulating power on the grid to increase. Hydro power turbines are designed to operate at a certain design point with a specific flow rate. The plants are operated away from the design point when used to regulate the supply and demand of electricity. This can cause a specific flow phenomenon to arise in the draft tube at part load conditions called a Rotating Vortex Rope (RVR) which causes dangerous pressure fluctuation able to damage blades and bearings. A solution to mitigate a RVR is to inject pulsating momentum into the draft tube by using an actuator operating at a certain frequency. A literature study was conducted and three techniques were numerically simulated using ANSYS Workbench 19.0 R3; a fluidic oscillator, a piston actuator and a synthetic jet actuator. A dynamic mesh was used to simulate the movement of the piston actuator and diaphragm of the synthetic actuator whilst the mesh of the fluidic oscillator was stationary. The relative errors of the three numerical models were all below 3 %. All devices showed promising results and could potentially be used to mitigate a RVR because they all have the ability to produce high energy jets. The fluidic oscillator had an external supply of water, whereas the other two did not, which means that it could inject the largest mass flow. The piston actuator required a driving motor to move the piston. The diaphragm of the synthetic jet actuator was moved by a Piezoelectric element. Advantages of the fluidic oscillator are that it has no moving parts, in contrary to the two other devices, it can directly be connected to the penstock or draft tube to obtain the required water supply and it is easy to install. It will most likely also be smaller compared to the other two for the same mass flow rate. It does however not generate a pulsating jet, but rather an oscillating jet. The other two devices generate pulsating jets, but have problems with low pressure areas during the intake stroke which can cause cavitation problems. These areas cause the formation of vortex rings close to the outlet. Simulations showed that a coned piston together with a coned cylinder outlet could decrease losses by almost 16 % compared to a normal piston and cylinder. It also decreased the risk for cavitation and the required force to move the piston. Otherwise, a shorter stroke length for a constant cylinder diameter or a longer stroke length for a constant volume displacement also decreased the risk for cavitation and required force. The gasket between the piston and cylinder is a potential risk for leakage. A solution to avoid critical low pressure areas is to install an auxiliary fluid inlet or valve which opens at a certain pressure for the piston actuator as well as the synthetic jet actuator. This will also allow larger mass flow rates and a higher injected momentum. Both devices are more complicated to install and require likely more maintenance compared to the fluidic oscillator. However, there exist many possible design options for the piston actuator. The design of the synthetic jet is more limited because of the diaphragm. The amplitude of the diaphragm also has a direct effect on the pressure levels. The losses increased proportional to the mass flow to the power of three which suggests that it is better to install many small actuators instead of a few large ones.

Höhere Drehzahlen, neue Anwendungen in elektrischen Fahrzeugen und der damit verbundene Leichtbau führen zu stärkeren Schwingungsphänomenen in elektrischen Drehfeldmaschinen. Besondere Bedeutung kommt dabei lateralen Rotorschwingungen zu, die sich akustisch bemerkbar machen und im Extremfall sogar zum Versagen des gesamten Systems führen können. In diesem Beitrag wird ein neuartiges Modell vorgestellt, welches rotordynamische Phänomene beliebiger Drehfeldmaschinen in transienten Fahrzuständen unter Berücksichtigung der vollen elektromagnetischen Kopplung abbilden kann. Im vorliegenden Beitrag wird eine FEM-Validierung des vorgeschlagenen Modells präsentiert. Danach wird ein Szenario vorgestellt, bei dem magnetisch angefachte Lateralschwingungen aufklingen. / Higher Speeds, new applications in electric vehicles and the need for lightweight structures lead to increasing occurrence of vibration phenomena in rotating field electrical machines. Lateral rotor oscillations take a particular role in this context, as they produce noise and may cause the entire system to fail in an extreme case. In this contribution, a novel modelling approach is presented, which allows for the fully coupled simulation of transient rotordynamics in all kinds of rotating field machines. This paper includes a FEM-validation of the proposed model. After that a scenario where self-excited lateral oscillations occur is presented.

Quantum computers are being developed to solve certain problems faster than classical computers. Instead of using classical bits, they use quantum bits (qubits) that utilize quantum effects. At Chalmers University of Technology, researchers have already built a quantum chip consisting of two superconducting transmon qubits and are trying to build systems with more qubits. To assist in that process, they make numerical simulations of the quantum systems. However, these simulations face an intrinsic computational limitation: the Hilbert space of the system grows exponentially with the number of qubits. In order to mitigate the problem: the simulations should be made as efficient as possible, by applying certain approximations, while still obtaining accurate results. The aim of this project is to compare several of these approximations, to see how accurate they are and how fast they run on a classical computer. This is done by modelling the qubits as quantum anharmonic oscillators and testing several cases: varying the energy levels of the qubits, increasing the number of qubits, and testing the rotating-wave approximation (RWA). These cases were tested by implementing two-qubit gates on the system. The simulations were all made using the Python library QuTiP. The results show that one should simulate using at least one energy level higher than the maximum energy level required for the gate to function. For larger systems, the RWA will make a big difference in simulation times, while still giving relatively accurate results. When using the RWA, the number of levels used does not seem to affect the results significantly and one could therefore use the lowest possible energy levels that can simulate the system.

Peptide drugs are used to treat a broad spectrum of diseases such as cancer and HIV and have many more promising applications, such as new vaccines against SARS-CoV-2. The most popular manufacturing method for peptides is solid-phase peptide synthesis (SPPS). The main drawback of SPPS is that it is a costly and wasteful process.  SpinChem is a company that provides technology solutions for chemical processes. Recently, SpinChem has started investigating if their Rotating Bed Reactor (RBR) is suitable for peptide synthesis. The goal of this project is to investigate how the RBR can make processes like SPPS more resource-efficient. The idea is that the RBR-system can maximize the solid-phase to liquid ratio (STL). The STL is the ratio of the volume of solid-phase material and the volume of liquid. By maximizing the STL, it is possible to manufacture peptides using less solvents and chemicals. The main quest of the project is formulated into a single question:  How does a high STL affect the efficiency of the RBR-system?  To answer the question, Minitab's statistical software and design of experiments (DOE) will be used to plan and perform experiments in both lab- and industrial scales. DOE factorial experiments are used to gain as much information as possible about the new RBR-system. The results are analyzed and summarized to make a solid foundation for the continued work on the new RBR application.  Peptide synthesis efficiency in the RBR-system is measured using ionic adsorption. The ionic adsorption rate is measured in both lab-scale and industrial-scale experiments. In the lab-scale experiments, the decrease of ions was on average 86,5% after just 15 s with an average STL of 0,936. The industrial-scale experiments showed a similar result where the average decrease in ions was 92,9% after 20 s with an average STL of 0,947. It was concluded that the RBR-system can reduce the consumption of washing-solvent in SPPS by up to 82%.

Generating an adverse pressure gradient (APG), using a rotating cylinder in the proximity of a plane wall under a laminar freestream flow, is studied numerically in this work. The magnitude of the generated APG is a function of the gap, G, between the cylinder and the wall, and the rotational speed of the cylinder, Ω. The flow in such a configuration is characterized by periodic transient vortex shedding at high Reynolds number. A numerical model for the computation of the transient flow for this configuration is developed using the ANSYS CFD simulation tool. The model is validated against published experimental and numerical data for similar flow configurations and excellent agreement is observed. A parametric study is carried out for different combinations of G and Ω for two different Reynolds numbers of 200 and 1000 to examine the development of the resulting separation bubble due to the generated APG. The mechanism of the boundary layer separation over the plane wall and the corresponding wake dynamics is investigated. Results are presented in terms of the distribution of the pressure coefficient as well as skin friction coefficient along the wall and flow patterns around and downstream of the cylinder in the proximity of the wall. The results of these computations confirm that using a rotating cylinder over a plane wall in a freestream flow is an effective technique to generate a controlled range of adverse pressure gradients.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1982. / Microfiche copy available in Archives and Science / Bibliography: leaves 108-109. / by Lawrence J. Pratt. / Ph.D.

This dissertation thesis deals with the measurement of insulation resistance for rotating electrical machines and polarization indices calculated from them. The first part contains a short theoretical introduction, methods of measurement and basic formulas for calculations. The second part discusses the results obtained in laboratory measurements in both the model and the real coil of high voltage machine. There are also elucidated some of the principles and causes of some phenomena with which the measurement of insulation resistance is encountered. The third part deals with the results of measurements on real machines. There are mainly discussed the dependences of insulation resistance and polarization index on the influences that occur in measurements such as temperature measured insulation, moisture in the insulation, but also the influence of measuring instruments on the measured values. It is also expressed how much these factors affect the measurement results. In addition, this part deals with some other influences that have a negative affect on the measurement of insulation resistance. There is processed a new methodology for measuring insulation resistence in the fourth part of this thesis. The need to develop a metodology of measuring is based on the needs of engineering practice, where is considerable inconsistency of measurement in the present time. Measurement, and often performed on the same machine, are not nowadays often comparable, because measurements are not met even the basic rules resulting from the findings of research and development, which were discovered in the last few decades. Measurement of insulation resistance in our nowdays methodology stagnated on the level of the seventies of 20th century. For this reason, we have developed a new methodology of measurement that takes into account all significant influences affecting the measurement. The purpose of the methodology is to ensure full repeatability and comparability of measurements not only on the same machine but on machines of the same type, in optimal cases, the machines of different types. There are the chapters "The objectives of the work" and "Conclusion" the part of the work. A very important chapter is "The contribution of thesis", which summarizes the original results of this work and results, the use of which is expected in engineering practice.