When constructing a marina, one must consider many factors for calculating the mooring forces transferred to the mooring system of the docks. The forces transferred from waves is of course one of the most important. The wave induced forces may be described in different orders, the first-order wave forces from the frequency domain and the second-order wave forces determined from a wave field of different standing waves acting together. All floating objects are subjected to these wave forces, but for different mooring systems the transferred mooring force may vary. To describe the need for different calculations depending on the mooring system, a comparison to a spring system is made for both a Seaflex hawser and a guided pile system, which illustrates a significant difference in transferred mooring load. This is due to the hysteresis giving a low spring constant to the Seaflex hawser, which in turn transfers very little of the frequency induced first-order forces to the mooring system. This gives the conclusion that different methods for scaling the Seaflex mooring system is needed, since the first-order wave forces are not as significant than for a semi-rigid mooring system.

Sheet metal forming is a technique widely used in todays industries as it enables fast transformation of metal sheets into parts of various shapes and sizes. Volvo GTO EBM in Umeå uses sheet metal forming in their production of truck cab body parts, and a challenge common for all industries using this technique is to avoid cracking in the formed metal. The present study has been conducted in order to increase the understanding of why produced articles sometimes crack, so that cracking can be prevented in future production. This has been done by studying how different variations in the production process are affecting the robustness of produced articles, partly by investigating variations in material properties and partly by running robustness simulations of a chosen article prone to crack. Material properties have been gathered for both cracked and non-cracked details of different articles, and thereafter been compared to each other using multivariate analysis. Furthermore, simulations have been run using the software AutoForm with the purpose to investigate factors such as feeding direction of metal sheets, variations in material properties and different forces and velocities used during forming. Experiments have also been conducted in order to compare the simulation model and simulation results with reality. From the material property analysis it could be seen that differences in material properties do exist between cracked and non-cracked materials, but that these differences vary between different articles. The robustness simulations indicated that a certain force called draw cushion force do affect the final robustness of an article the most, compared to the other affecting factors investigated in this study. Moreover, the simulation set-up did seem to agree with reality, while the simulated material thinning deviates more than 20 \% from the real one. This may result from an inadequate modeling of friction in the simulations. In conclusion, material properties are important concerning cracking during sheet metal forming, and the draw cushion force seems to have the strongest influence on article's final robustness.

No description available.

Pulmonary Artery Hypertension (PAH) is a condition that can affect people as a consequence of infections or diseases such as lung disease, high blood pressure or pneumonia. When afflicted by these diseases, low oxygen content in the lung tissue causes the pulmonary arterial soft muscle cells (PASMC) located in the walls of the pulmonary arteries to chronically swell up. As a result, the arteries are constantly narrowed. This can in many cases be fatal as the arteries become clogged and the heart is forced to pump more blood to the lungs, causing an enlargement of the right heart chamber which eventually may lead to heart failure. This irreversible swelling of the PASMC is the cause for PAH. To find a treatment for this incurable disease, the mechanisms of the vasoconstriction need to be investigated.  Spectroscopy is the study of the interactions between light and matter and is a tool that can be used to gain knowledge in the matter of the expansions of the PASMC. In particular, Raman spectroscopy that targets the inelastic interactions can be used since it registers dynamic changes of cells.  To simulate an oxygen deprived environment, a micro-fluidic system designed for use in cellular experiments has been developed. Tests of the prototypes showed strong Raman signals from the polymeric material of the system itself. These signals overshadowed the signals from the observed sample. The objective of the experiments presented in this report was to test whether the signals from the micro-fluidic system could be eliminated by adding spacing between the polymer and the sample.  The experiment was conducted by collecting data of samples from baker's yeast prepared in the micro-fluidic system at different z-distances. By this the optimal spacing between the polymer of the micro-fluidic system and the sample could be determined. This experiment concluded that the sample needed to be placed 1.54 mm further from the micro-fluidic system in order to test human lung tissue at 2 mW laser intensity.

In forestry it is important to have accurate information about the forest. LiDAR (laser scanning) can be used to scan vast areas of forest and from the data extract information about the trees. The purpose of this thesis is to develop a simulator for LiDAR data. The simulator will be tested on a method for tree localization (Holmgren and Lindberg 2013) to see how parameters like tree density and laser frequency effects the accuracy of the localization. First a simulator which uses simple shaped trees (in the shape of cones) is written. Later on a tree model based on real laser data is created by the use of histogram density estimation. Ray-tracing is used to simulate the LiDAR data which the trees give rise to. This is done by following each ray of laser and see where it is reflected. The tree localization method is tested on the data and we report the following findings: 1: The percentage of correctly located trees decreases with increasing tree density. 2: Larger trees yields an increase in false trees found by the localization method. 3: Higher laser pulse density decreases the number of false trees. 4: The minimum radius at which the localization method start fitting ellipsoids greatly effects the number of false trees. Smaller radius yield more false trees.

For a mechanical system exposed to repeated cyclic loads fatigue is one of the most common reasons for the system to fail. However fatigue failure calculations are not that well developed. Often when fatigue calculations are made they are done with standard loads and simplified cases. The fatigue life is the time from start of use until the system fails due to fatigue and there does exist some building blocks to calculate the fatigue life. The aim for this project was to put these building blocks together in a workflow that ca be used for calculations of the fatigue life. The workflow was built so that it should be easy to follow for any type of me- chanical system. The start of the workflow is the load history of the system. This is then converted into a stress history that is used for the calculations of the fatigue life. Finally the workflow was tested with two test cases to see if it was possible to use. In Algoryx Momentum the model for each case was set up and then the load history was extracted for each time step during the simulation. To convert the load history to stress history FEM calculations was needed, this was however not a part of this project so the constants to convert loads to stress was given. Then with the stress history in place it was possible to calculate the fatigue life. The results from both test cases were that it was possible to follow every step of the workflow and by this use the workflow to calculate the fatigue life. The second test also showed that with an optimization the system was improved and this resulted in a longer lifetime. To conclude the workflow seems to work as expected and is quite easy to follow. The result given by using the workflow shows the fatigue life, which was the target for the project. However, to be able to evaluate the workflow fully and understand how well the resluts can be trusted a comparison with empiric data would be needed. Still the results from the tests are that the workflow seem to give reasonable results when calculating fatigue life.

There are about 17 million X-ray procedures performed in Sweden every year. Various methods are used to determine the risk for the patient, and for the staff. The objective of this project was to map X-ray scatter coming out of a patient as a result of interactions between the radiation and body tissue during certain medical procedures that involve fluoroscopy. Flouroscopy is a type of X-ray imaging method that generates a moving picture which allows an operator to view in-body procedures live. A successfully created map of the radiation field can work as a tool for risk analysis concerning the dose of radiation of which the medical staff is exposed to, this parameter will later be described as the effective dose (E). The effective dose is a tool for assessment of the risk of developing lethal cancer due to radiation exposure. This report will also investigate the radiation that reaches the eye lens of the staff, since the maximum recommended dosage for the eye lens has been lowered recently when it was discovered that the eye lens was more sensitive to radiation than previously known. In this report data was collected from radiation exposure situations, and it was concluded that distance is a good protector against radiation, which agree well with theory discussed in the report. Another theory which was discussed in the paper states that positions behind the X-ray tube will be exposed to the highest amount of radiation, this was also proven. The measured data from investigating protective equipment showed that the equipment in place was effective. / <p>The author changed last name to Folkunger due to marriage shortly after this publication.</p>

In this study the volume determination which is a part of the doseplanning for patients with thyrotoxicosis was investigated. The aim was to find an accurate method to determine the active volume with single photon emission tomography (SPECT) which in several studies have shown better results than with the currently used method planar scintigraphy (PS). This was implemented on the Xeleris 3.1 by General Electric (GE) at the University Hospital of Umeå (NUS). The examination time with SPECT is required not to be significantly longer than the examination time with PS. Despite the relatively short examination time, the accuracy of the volume determination should be more accurate. This was analyzed with a true value of the volume, conducted with Monte Carlo simulations of digital anthropomorphic phantoms. It is also important that the developed method is user friendly. The study included ten patients with thyrotoxicosis from which, relative activity uptakes were measured. These uptakes were specified in 22 digital XCAT phantoms which were random sampled with respect to phantom mass. The Monte Carlo program "simulating medical imaging nuclear detectors" (simind) was used to simulate the SPECT-system. The projection images were ordered subset expectation maximization (OSEM) reconstructed and Butterworth filtered. Unfiltered images were used to compare volume calculations with filtered ones. The volume of the thyroid was segmented using threshold values applied to all voxels in the image-sets and the optimization of the thresholds was conducted by numerical calculations. The results in this study shows that the best choice of intensity threshold value is 21.1(24)% of the maximum voxel value for all phantoms. The threshold is valid for OSEM iteration number five and unfiltered image-sets. Butterworth filtered images were less suitable to use than unfiltered images when the thyroid volume was calculated with data from SPECT-simulations of phantoms.

A search for heavy neutral Higgs bosons in the τ_μ τ_had channel is presented. The analysis was performed using approximately 32 fb^−1 of 13 TeV proton-proton collision data with the ATLAS detector and improves upon earlier ATLAS searches through the use of Boosted Decision Trees (BDT).

No description available.