Earthquake Analysis of Pipe Supports in Nuclear Power Plants

This is the resulting rapport from a master thesis in the field of structural analysis, with a focus on earthquake engineering. In this project are pipe supports’ impacts on seismic design analysed. This is done by modelling a building, pipe supports and a pipe system in two different computer softwares. One of them is commonly used for design of pipes at nuclear plants, and the other has applications in many fields of mechanics. Earthquake data for seismic design at nuclear plants in Sweden is used as input and different kinds of analysis are performed. Output from the two softwares is compared to see how the responses differ and if it is related to the pipe supports. The eigenmodes and forces calculated differ between the two softwares. The difference in eigenmodes and therefore also the forces may be explained by modelling issues with the pipe bends. However, the modelling technique for the pipe supports does not seem to impact the result

Odour problems in buildings – result of 682 cases

Various odours can cause a negative perception of the indoor air quality. The intensity of the odour can fluctuate for example due to weather conditions, ventilation, and use of the building. In addition, the degree of odour perception among individuals, is highly variable. Absence of an adequate measuring method makes it difficult to get a systematic and uniform description of the odour and where in the building the odour is most noticeable. This leads to challenges in clarifying the causes and relevant measures are often difficult to submit. Examination of 682 cases with odour in dwellings and commercial buildings have shown that causes and remedial actions can be revealed by a systematic procedure. Complainers are asked to characterize the smell in few, standardised words and describe where and when they experience the odour. This information is often crucial for the surveyor when performing the following building examination.publishedVersio

Forecasting Volatility - An Empirical Investigation of Implied Volatility and Its Information Content

The purpose of this thesis is to evaluate volatility forecasts by testing the predictive power of implied volatility vis-à-vis model based forecasts. Furthermore we test if implied volatility contains any additional information beyond that captured by the model based forecasts. A number of time series models are fitted to historical data. The fitted models are then used to forecast volatility. The procedure is repeated to produce a series of forecasts. The forecast are evaluated against out-of-sample realized volatility through regression analysis. Finally we test for additional information in implied volatility through GMM and OLS estimation. We find that volatility can be predicted to some extent. Tests indicate that implied volatility is the superior forecast of future realized volatility when compared bilaterally against time series models. Implied volatility does not contain any additional information about future realized volatility in levels when orthogonalized to all model based forecasts. There is however some incremental information regarding changes in future realized volatility

Investigating app users: Creating personas for global applications

There are over 1.5 million Android applications on the market available today. This makes it important for the developers to know their customers. Knowing what their customers want from the application will grant the developers insight in what features they should implement. This report will present different methods of finding users and their behaviors in a certain application. The users' behaviors will be divided into different patterns, which then are translated into user personas and presented to the developers as a result. \\ \\ In order to find actual users, various methods were used. The different approaches were compared to each other in the aspects of their time consumption and value for the result. The most effective way to find users was through surveys posted in a app specific beta test channel that was set up by the developers for users to join voluntarily. The surveys gave information about the user behavior when interacting with the app. The respondents were able to sign up to help the project even more by participating in interviews. The interviews were held with the users who provided their email address and these interviews gave personality traits that could be used to make the personas more lifelike. The surveys and the interviews combined gave sufficient information to create personas for the majority of the user base with an error margin of seven percent

Hydrogen Bond Induced Nonmonotonic Composition Behavior of the Glass Transition in Aqueous Binary Mixtures

The glass transition temperature, T(g), of a binary mixture commonly varies monotonically between the T(g)s of its two components. However, mixtures of strongly associating liquids can instead exhibit a nonmonotonic T(g) variation. The origins of such nonideal mixing behavior have often been correlated with composition dependent structural variations. For binary mixtures between a hydrogen- (H-) bonded liquid and water, however, such behavior is generally not well understood. The ubiquity and importance of aqueous mixtures both in nature and in man-made applications stresses the needed for a better understanding. We here demonstrate nonmonotonic T(g) variations in binary mixtures of n-propylene glycol monomethyl ethers (nPGMEs) and water, where the composition dependent T(g) show maxima within an intermediate composition range. We show that these T(g) maxima correspond to crossovers in the composition dependence of the step amplitude in the isobaric heat capacity at T(g). We further demonstrate that the observed effects are caused by H-bond interactions involving the nPGME hydroxyl group. We can account for our obervations using a simple model based on two effects due to the added water: (i) an H-bond induced formation of effective relaxing entities and (ii) a plasticizing effect at high water contents

The relationship between CDS spreads and bond spreads – an empirical comparison

Syfte: Syftet är att undersöka sambandet mellan CDS spreaden och bond spreaden, samt att jämföra dessa över tid. Detta genomförs genom att testa för ett kointegrationssamband samt Granger-kausalitet mellan CDS spreaden och bond spreaden för varje enhet som ingår i urvalet, och för olika perioder. Också deskriptiv statistik används. Metod: Kvantitativ metod: Augmented Dickey-Fuller test, KPSS, Engle-Granger test, Johansen-test, Granger kausalitet Teoretiska perspektiv: Prissättningsmodeller för kreditrisk. Arbitragesamband. Empiri: Bond spread och CDS spread för 29 st företag (klassificerade som financials) från S&P 350 och S&P 500. Tidsperiod: 2004-01-01 till 2008-11-24. Slutsatser: Undersökningen visar på att de undersökta företagens CDS- respektive bond-spread uppvisar varierande grad av kointegration under de olika tidsperioderna som undersökts. Därmed är det svårt dra några egentliga slutsatser av de tvetydiga resultaten. Däremot står det att finna i materialet att både den genomsnittliga CDS-spreaden, genomsnittliga bond-spreaden och den genomsnittliga skillnaden dem emellan ökar markant under undersökningens sista 17 månader, vilka är präglade av finansiell oro

On the physics of frequency domain controlled source electromagnetics in shallow water, 2: transverse anisotropy

Author Posting. © The Authors, 2017. This article is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 211 (2017): 1046–1061, doi:10.1093/gji/ggx360.In recent years, marine controlled source electromagnetics (CSEM) has found increasing use in hydrocarbon exploration due to its ability to detect thin resistive zones beneath the seafloor. It is the purpose of this paper to evaluate the physics of CSEM for an ocean whose electrical thickness is comparable to or much thinner than that of the overburden using the in-line configuration through examination of the elliptically-polarized seafloor electric field, the time-averaged energy flow depicted by the real part of the complex Poynting vector, energy dissipation through Joule heating and the Fréchet derivatives of the seafloor field with respect to the sub-seafloor conductivity that is assumed to be transversely anisotropic, with a vertical-to-horizontal resistivity ratio of 3:1. For an ocean whose electrical thickness is comparable to that of the overburden, the seafloor electromagnetic response for a model containing a resistive reservoir layer has a greater amplitude and reduced phase as a function of offset compared to that for a halfspace, or a stronger and faster response, and displays little to no evidence for the air interaction. For an ocean whose electrical thickness is much smaller than that of the overburden, the electric field displays a greater amplitude and reduced phase at small offsets, shifting to a stronger amplitude and increased phase at intermediate offsets, and a weaker amplitude and enhanced phase at long offsets, or a stronger and faster response that first changes to stronger and slower, and then transitions to weaker and slower. By comparison to the isotropic case with the same horizontal conductivity, transverse anisotropy stretches the Poynting vector and the electric field response from a thin resistive layer to much longer offsets. These phenomena can be understood by visualizing the energy flow throughout the structure caused by the competing influences of the dipole source and guided energy flow in the reservoir layer, and the air interaction caused by coupling of the entire sub-seafloor resistivity structure with the sea surface. The Fréchet derivatives are dominated by preferential sensitivity to the vertical conductivity in the reservoir layer and overburden at short offsets. The horizontal conductivity Fréchet derivatives are weaker than to comparable to the vertical derivatives at long offsets in the substrate. This means that the sensitivity to the horizontal conductivity is present in the shallow parts of the subsurface. In the presence of transverse anisotropy, it is necessary to go to higher frequencies to sense the horizontal conductivity in the overburden as compared to an isotropic model with the same horizontal conductivity. These observations in part explain the success of shallow towed CSEM using only measurements of the in-line component of the electric field.This work was supported at WHOI by an Independent Research and Development award, and by the Walter A. and Hope Noyes Smith Chair for Excellence in Oceanography