Utilizing Phase Change Materials (PCM) for Latent Thermal Energy Storage (LTES) applications have previously been extensively researched as a measure to reduce greenhouse gas emissions from energy consumption. In order to make use of the waste heat from industrial processes for LTES purposes, a new demand emerged for PCMs capable of phase change in mid-temperature ranges of 100 °C - 200 °C. This higher temperature requirement made most of the previously studied material inapplicable as they had much lower melting and solidification temperatures. With this in mind, a new generation of PCMs consisting of Sugar Alcohols (SA) has been proposed. Erythritol is seen as an especially promising SA with good thermophysical properties for LTES purposes. However, it has been shown to suffer from severe supercooling, which makes it unreliable in real applications. To eradicate this issue, two additives, Graphene Oxide (GO) and Polyvinylpyrrolidone (PVP) at varying mass fractions were mixed with pure erythritol to form a composite which was studied using the Temperature-history (T-history) method to determine its effectiveness in reducing supercooling. Results show that at its most effective mass fraction, GO reduces supercooling by 28 oC and a 31 oC reduction is seen by the addition of PVP. The impacts on the duration of crystallization was also documented and analyzed using the same method. It was observed that the duration of crystallization was increased with increasing mass fractions of the additives. Other important properties of the composites were also studied in order to determine the overall feasibility for industrial applications. It includes analysis of the storage capacity through latent heat, changes in viscosity along with impacts on thermal diffusivity of the composites. / Att använda fasändringsmaterial (PCM) för termisk energilagring i form av latent värme (LTES) har tidigare extensivt forskats och undersökts som en lösning för att minska utsläppen av växthusgaser från energiförbrukning. För att utnyttja spillvärme från industriella processer för LTES-ändamål uppstod en efterfrågan på PCM som ändrar fas i temperaturer mellan 100 °C - 200 °C. Detta krav på högre temperatur gjorde att de flesta av de tidigare aktuella materialen inte kunde tillämpas eftersom de hade mycket lägre smält- och kristalliseringstemperaturer. Med detta i åtanke har en ny generation av PCM bestående av sockeralkoholer (SA) föreslagits. Erytritol ses som ett särskilt lovande SA med goda egenskaper för LTES-ändamål. Den har dock visat sig drabbas av svår underkylning, vilket gör den opålitligt i verkliga tillämpningar. För att utrota detta problem blandades två tillsatser, Graphene Oxide (GO) och Polyvinylpyrrolidone (PVP) vid olika massfraktioner med ren erytritol för att bilda en komposit som studerades med metoden Temperature-history (T-history) för att bestämma dess effektivitet på att minska underkylningen. Resultaten visar att GO på sin mest effektiva massfraktion minskar underkylningen med 28 oC och tillsats av PVP lyckats minska den med som mest 31 oC. Påverkningarna på varaktighet av kristallisering dokumenterades och analyserades med samma metod. Det var observerad att varaktigheten av kristallisering ökades med ökande massfraktioner av tillsatserna. Även andra viktiga egenskaper hos kompositerna studerades för att avgöra rimligheten att använda dessa för industriella tillämpningar. Det inkluderar analys av lagringskapaciteten genom latent värme, förändringar i viskositet tillsammans med påverkan på kompositernas termiska diffusivitet.

One of the most difficult tasks towards designing earthquake resistant structures is the determination of critical earthquakes. Conceptually, these are the ground motions that would induce the critical response in the structures being designed. The quantification of this concept, however, is not easy. Unlike the linear response of a structure, which can often be obtained by using a single spectrally modified ground acceleration history, the nonlinear response is strongly dependent on the phasing of ground motion and the detailed shape of its spectrum. This necessitates the use of a suite (bin) of ground acceleration histories having phasing and spectral shapes appropriate for the characteristics of the earthquake source, wave propagation path, and site conditions that control the design spectrum. Further, these suites of records may have to be scaled to match the design spectrum over a period range of interest, rotated into strike-normal and strike-parallel directions for near-fault effects, and modified for local site conditions before they can be input into time-domain nonlinear analysis of structures. The generation of these acceleration histories is cumbersome and daunting. This is especially so due to the sheer magnitude of the data processing involved. The purpose of this thesis is the development and documentation of PC-based computational tools (hereinafter called EQTools) to provide a rapid and consistent means towards systematic assembly of representative strong ground motions and their characterization, evaluation, and modification within a performance-based seismic design framework. The application is graphics-intensive and every effort has been made to make it as user-friendly as possible. The application seeks to provide processed data which will help the user address the problem of determination of the critical earthquakes. The various computational tools developed in EQTools facilitate the identification of severity and damage potential of more than 700 components of recorded earthquake ground motions. The application also includes computational tools to estimate the ground motion parameters for different geographical and tectonic environments, and perform one-dimensional linear/nonlinear site response analysis as a means to predict ground surface motions at sites where soft soils overlay the bedrock. While EQTools may be used for professional practice or academic research, the fundamental purpose behind the development of the software is to make available a classroom/laboratory tool that provides a visual basis for learning the principles behind the selection of ground motion histories and their scaling/modification for input into time domain nonlinear (or linear) analysis of structures. EQTools, in association with NONLIN, a Microsoft Windows based application for the dynamic analysis of single- and multi-degree-of-freedom structural systems (Charney, 2003), may be used for learning the concepts of earthquake engineering, particularly as related to structural dynamics, damping, ductility, and energy dissipation. / Master of Science

Elektrokardiografi är en vanligt förekommande undersökning inom hälso- och sjukvården då undersökningen är icke-invasiv och ger en bra överblick över hjärtats elektrofysiologiska status. Ett vanligt fel vid EKG är elektrodplacering i andra respektive tredje intercostala utrymmet istället för i fjärde intercostala utrymmet (IC4), vilket bland annat kan medföra reducering av R-vågs amplituden samt påverka datortolkningen. Syftet med arbetet var att se om avvikande EKG-kurvor uppstår vid omplacering av elektroderna V1 och V2 i andra och tredje intercostala utrymmet vid jämförelse med fjärde intercostala utrymmet på friska vuxna. I studien ingår 50 deltagare i åldern 18-48. Den statistiska analysen utfördes med hjälp av parvis T-test samt Fisher exact test. Jämförelsen mellan de olika placeringarna resulterade i en signifikant minskning av R-vågsamplituden (p <0,001) för samtliga kombinationer. En signifikant minskning visades i R-vågsduration i jämförelsen Intercostalrum 2 (IC2) versus (vs) IC4 i V2. För ST-sträckan visade båda avledningarna för jämförelsen IC2 vs IC4 en signifikant skillnad (p<0,001). Datortolkningen visade en signifikant skillnad för IC2 vs IC4 (p0,006) samt IC3 vs IC4 (p<0,001).  Omplacering av elektroder medför förändrad datortolkning när det vid en standardplacering visar ett normalt EKG, vilket kan ge en inverkan på patientens fortsatta handläggning och eventuella diagnos. / Electrocardiography is commonly used in healthcare as the examination is non-invasive and provides a good overview of the heart's electrophysiological status. A common error in ECG positioning is placement in the second or third intercostal space, which among other things can lead to a reduction in R wave amplitude and affect the computer interpretation. The aim of the study is to see if deviant ECG curves occur when repositioning the electrodes V1 and V2 in the second and third intercostal space when compared to the fourth intercostal space. The study includes 50 healthy adults aged 18-48. The statistical analysis was performed using paired t tests and Fisher exact test. The comparison resulted in a significant reduction in R wave amplitude (p <0.001) for all combinations. A significant decrease was shown in R wave duration in the comparison of IC2 vs IC4 in V2. For the ST segment, both leads for the comparison IC4 vs IC2 a significant difference was presented (p <0.001). For the computer interpretation, a significant difference was shown for IC2 vs IC4 (p0.006) and IC3 vs IC4 (p<0.001). Repositioning of electrodes leads to a different computer interpretation when in standard positioning shows a normal ECG, which may lead to misdiagnosis.

Measuring and tracking the employee turnover rate is a crucial part when evaluating a company’s performance. An important part of this is measuring the employment duration within an organization. The purpose of this report is to investigate if employment duration in a food retail company can be explained by predetermined variables using multiple linear regression. Data from five years ago until today has been collected and processed to analyze and fit the best choice of the linear model. Gender, employment rate, industry experience and age are the predictors used for conducting the analysis. The result shows that a low linear correlation can be seen between employment duration and the explanatory variables: gender, employment rate, industry experience and age. In the discussion, the results are analyzed as well as potential problems and improvements of the regression.

L’approche de la carrière criminelle a été appliquée à maintes reprises auprès de délinquants sexuels afin d’approfondir les connaissances relatives à leur participation criminelle, à la fréquence de leur passage à l’acte, à la durée de leur parcours criminel, à la gravité de leurs crimes et au polymorphisme dont ces délinquants font preuve. Parallèlement à l’essor des nouvelles technologies, un besoin grandissant d’en apprendre davantage sur la carrière criminelle des auteurs de leurre informatique s’est fait ressentir. À ce jour, peu d’études ont analysé le parcours criminel emprunté par ces cyberdélinquants sexuels en ayant recours au cadre d’analyse de la carrière criminelle. Afin de remédier à cette limite, le présent mémoire a comme objectif principal d’analyser les parcours criminels des auteurs de leurre informatique afin d’élargir les connaissances quant à la participation, la fréquence, la durée, la gravité et le polymorphisme. Plus précisément, l’objectif spécifique est d’analyser les tendances en termes de carrières criminelles. Pour ce faire, une analyse de profils latents a été menée auprès d’un échantillon de 1 201 auteurs de leurre. Les résultats indiquent l’existence de divers parcours criminels des auteurs de leurre et mettent en lumière quatre profils, soit (1) l’auteur de leurre « ponctuel à délinquance unique », (2) l’auteur de leurre « versatile tardif », (3) l’auteur de leurre « délinquant sexuel spécialiste » et (4) l’auteur de leurre « polymorphe prolifique ». Le premier profil identifié est composé d’auteurs de leurre ne commettant qu’un seul crime à travers leur parcours criminel selon les données officielles. Le second profil, pour sa part, regroupe les individus commettant plusieurs crimes sexuels et non sexuels et qui mettent fin tardivement à leur carrière criminelle. Ensuite, le troisième profil identifié comprend les auteurs ayant un penchant pour les crimes de sexuels, bien que leur carrière criminelle soit limitée en termes de participation et de fréquence. Dernièrement, le quatrième profil est constitué d’auteurs polymorphes commettant une variété de crimes sexuels et non sexuels. / The criminal career approach has been extensively applied in the context of sexual delinquency and allowed to deepen knowledge regarding the crimes committed by sex offenders, the duration of their criminal involvement, the seriousness of their criminal behaviors, and the variety of crimes they commit. Along with the rise of new technologies, there has been a growing need to learn more about the criminal careers of online groomers. To date, no studies have analyzed the criminal path of these online sex offenders using a criminal career framework. To remedy this limitation, the main objective of this paper is to analyze the criminal paths of online groomers as to broaden knowledge on participation, frequency, duration, seriousness, and versatility. Specifically, the objective is to identify tendencies in regards to their criminal careers. To do so, a latent profile analysis was performed on a sample of 1 201 online groomers. The results support the existence of multiple delinquent paths of individuals who sexually solicit youth online and highlight the existence of four profiles: (1) the “one-timer” groomer, (2) the “versatile and late” groomer, (3) the “specialist sex offender” groomer, and (4) the “versatile and prolific” groomer. The first profile identified consists of online groomers committing a single crime across their criminal path. The second profile includes individuals who commit multiple sexual and non-sexual crimes and who end their criminal career belatedly. The third identified profile includes perpetrators with a preference for sexual crimes, but whose criminal careers are limited in terms of participation and frequency. Lastly, the fourth profile is composed of versatile offenders committing a variety of sexual and non-sexual crimes.

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