The purpose of this master thesis is to implement and validate a Power System Stabilizer (PSS) to a generator at Trängslet hydropower station in Dalarna, Sweden. Problems with local rotor oscillations can occur at the hydropower station when power is transferred on a new power line (130 kV) from Northern to Southern part of Dalarna. To ensure good operation properties on this power line Fortum Generation AB and Fortum Distribution AB wants to activate a PSS on a generator. There have been investigations in which situations and what equipment that contributes to rotor oscillations. When this is known the PSS is tuned to damp these oscillations by choosing a good set of parameters. The most important parameters for good performance are to choose amount of gain and phase compensation. The chosen set of parameters are verified with a test in the power station to ensure that the task is completed. Test results shows that the magnitude of the first swing in rotor oscillation is almost the double than what PSS/E shows, but good correlation five seconds after initialization of the disturbance. The inherent dampening performance of the generator is much better in reality than in simulation. The chosen set of parameters contributes to rotor oscillation dampening in a magnitude approximately equal to simulation results in PSS/E, why the conclusion has been made that the implementation of the PSS is successful. There has also been made simulations with different power outputs and amount of generators synchronized whose results shows that damping is greatly increased with the chosen PSS.

In the last decade, PSS (Product/ Service System) emerged as a new effective business model in helping manufacturers increase significantly productivity and customer’s satisfaction, whist minimizing environmental impact. PSS contributes drastically to the development of an innovative transaction trend, in which rather than just providing physical products separately, industrial Companies are more focusing on integrated service offers and customer’s need fulfillment.    However, to implement successfully PSS, manufacturers have to overcome many challenges and uncertainties. The uncertainties in the PSS planning phase are related to market, environment or company analysis; reliability, product/service integration, supplier coordination etc in the design and development stages are considered as potential uncertainties. Uncertainty is defined as “State of deficiency of information related to a future event” (Sakao et al., 2009). In which, risks derived from negative side of uncertainties may reduce efficiency of the model or even make the implementation process fail to some extent. If the uncertainty is resolved in a favorable way, risks can be seen as potential business opportunities for the development of PSS Companies. While many Companies already have their own uncertainty management initiative; others just utilize their long time experience to treat uncertainties. Therefore, numerous Companies are seeking a comprehensive uncertainty management framework that could be applicable in most circumstances. In order to fulfill this urgent need, our thesis aimed to develop a holistic framework in order to manage risks occurred in PSS planning, design and development stages. Based on previous valuable PSS researches and useful empirical data collected, our dissertation first determined successfully critical uncertainty factors and potential business opportunities exploited from those. In addition, the research investigated elaborately PSS product quality thresholds and producers’ perception on reliability of their products before constructing a general uncertainty management framework. In which the whole management process based on Active Risk Management philosophy, included Risk Management Planning, Risk Identification, Risk Assessment and Prioritization, Risk Quantification, Risk Response Planning, Risk Tracking and Control were introduced as a helpful guideline to support PSS Companies to treat effectively uncertainties in PSS planning, design and development.

Organic conducting polymer, poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS), is widely recognized for its electro-actuation mechanism and is used in flexible electronics. Its high potential as actuator is based on a strong coupling between chemical, mechanical and electrical properties which directly depends on external stimuli. There is no model today to describe the interplay between moisture absorption, mechanical expansion and electrical stimulus. Elucidating the role of each component in the effective actuation properties is needed to further optimize and tailor such materials. The objective of this thesis is to develop a macroscopic model to describe water sorption kinetics of the PEDOT:PSS film. We used gravimetric analysis of pure PEDOT:PSS film of three different thicknesses to investigate absorption kinetics over a broad range of temperatures and relative humidity. Our results revealed that the moisture uptake of PEDOT:PSS film does not follow Fickian diffusion law due to the retained amount of water after desorption process. We used an existing diffusionreaction model to describe this behavior, and COMSOL Multiphysics and MATLAB software programs to implement it. We observed that the generic model we used in our work could predict polymer behavior with 95% accuracy. However, our model was not able to properly represent the data at very high relative humidity at low temperature, which was attributed to the excessive swelling of the film. Also, we examined a relation between the moisture content of PEDOT:PSS and its mechanical strain and electrical conductivity. The results presented here are the first step towards a general multiphysics electro-thermo-mechanical description of PEDOT:PSS based actuators.

As the requirements to operate the electric power system become more stringent and operating costs must be kept to a minimum, operators and planners must ensure that power system models are accurate and capable of replicating system disturbances. Traditionally, load models were represented as static ZIP models; however, NERC has recently required that planners model the transient dynamics of motor loads to study their effect on the postdisturbance behavior of the power system. Primarily, these studies are to analyze the effects of fault-induced, delayed voltage recovery, which could lead to cascading voltage stability issues. Genetic algorithms and constrained multivariable function minimization are global and local optimization tools used to extract static and dynamic load model parameters from postdisturbance data. The genetic algorithm's fitness function minimizes the difference between measured and calculated real and reactive power by varying the model parameters. The fitness function of the genetic algorithm, a function of voltage and frequency, evaluates an individual\'s difference between measured and simulated real and reactive power. While real measured data was unavailable, simulations in PSS/E were used to create data, and then compared against estimated data to examine the algorithms' ability to estimate parameters. / Master of Science

Bakgrund: Sömnproblematik och stress är relativt utbrett i samhället och kan inverka på varandra. Stress kan påverka en persons sömnvanor och sömnbrist kan leda till att stress hanteras på ett annorlunda sätt. Stress och sömnbrist har visat sig vara en återkommande faktor hos studenter och studier gjorda på fysioterapeutstudenter har visat en hög prevalens av stress. Sömnvanorna och eventuella samband mellan stress och sömn är mindre undersökta. Syfte: Syftet var att kartlägga självskattad stress och självskattade sömnvanor bland Fysioterapeutstudenter. Syftet var också att se om det finns något samband mellan dessa faktorer. Metod: En studie med kvantitativ design utfördes med en digital enkät som datainsamlingsmetod på 200 fysioterapeutstudenter i termin 1-6 vid Luleå tekniska universitet. Enkäterna innehöll frågor om självskattad upplevd stress (PSS-10) och sömnvanor. Resultat: Studien hade totalt 100 respondenter, varav 59 kvinnor och 41 män. Majoriteten av deltagarna hade en måttlig stress och kvinnorna var mer stressade än männen. De flesta deltagare hade en sömntid på mer än sju timmar per natt den senaste månaden och majoriteten uppgav att de fått tillräckligt med sömn. Det fanns ingen indikation på ett samband mellan självskattad stress och antal sömntimmar. Konklusion: Majoriteten av fysioterapeutstudenterna upplever stress i olika grad där måttlig stress var mest utmärkande. De flesta sover enligt allmänna rekommendationer och anser sig få tillräckligt med sömn. Inget samband noterades mellan stress och sömn. Resultaten går överlag i linje med tidigare studier även om metodologiska faktorer gör det något svårt att jämföra. Mer studier behövs för att undersöka stress och sömnvanor och eventuella samband mellan dessa faktorer bland studenterna.

This dissertation introduces a social exchange perspective of intention to quit and examines the relationship of several work-related and non work-related variables with intention to quit. Specifically, the relationships between the following ? perceived organizational support (POS), perceived supervisor support (POS), family responsibility, kinship responsibility ? and intention to quit were examined. POS and PSS were examined to provide a better understanding of the role each plays in the development of intention to quit. Family responsibility and kinship responsibility were examined because prior research has generally ignored the role each may play in the development of intention to quit. A cross-sectional design was utilized and data was collected from three prison sites within the Mississippi Department of Corrections (MDOC) using a questionnaire. Correctional officers at each of the three sites were asked to complete a questionnaire, were told their participation was voluntary and their responses would be held in complete confidentiality, and were given time during working hours to complete the questionnaire. The data collection yielded 392 usable questionnaires. Hierarchical regression was used to analyze the hypotheses. By utilizing social exchange theory, this dissertation provided a broader theoretical perspective of intention to quit by allowing the inclusion of work-related and non work-related variables. The results provided support for the role POS and PSS play in the development of intention to quit. Specifically, POS and PSS do not appear to have a direct effect on intention to quit. Rather, the relationship seems to be fully mediated by job satisfaction and organizational commitment. No support was found indicating family responsibility or kinship responsibility had an effect on intention to quit. However, possible limitations concerning the measurement of family responsibility and kinship responsibility were noted and further development of these measures may be necessary.

Prokrastinering är ett mycket allvarligt men också relativt vanligt uppskjutarbeteende, särskilt bland studenter, som kopplas till bland annat stress och dåliga betyg. På senare år har dock forskare argumenterat för existensen av ett gynnsamt uppskjutarbeteende, känt som strategisk förskjutning. Syftet med denna studie var att utforska hur personer som strategiskt förskjuter upplever och hanterar stress i vardagslivet. Detta begrundas i att det saknas forskning om strategisk förskjutning och dess potentiella negativa effekter, vilket behövs eftersom strategisk förskjutning anses vara en gynnsam studiestrategi för studenter. Studiens två frågeställningar var (i) om det fanns det ett signifikant samband mellan strategisk förskjutning och upplevd stress, samt (ii) hur stor del av variansen i upplevd stress kunde förklaras av strategisk förskjutning? För att besvara frågeställningarna delades pappersenkäter ut till studenter på Karlstads universitet. Enkäten bestod av New Active Procrastination scale (mätte strategisk förskjutning), Perceived Stress Scale 10 (mätte upplevd stress), samt bakgrundsfrågor. Resultaten från dataanalysen visade att strategisk förskjutning korrelerade signifikant, medelstarkt och negativt med upplevd stress (r[99] = -0,314, p<0,001). Strategisk förskjutning förklarade 8,9 procent av variansen i upplevd stress. ANOVA-resultatet visade att den förklarade variansen var signifikant (F[1,97] = 10,612, p<0,002). Det fanns en del metodologiska problem med denna studie. Det allvarligaste problemet var översättningen av NAPS, vilket på många sätt inte var adekvat vilket skadade instrumentets liksom studiens reliabilitet och validitet. Studiens resultat bör därför tolkas med försiktighet. / Procrastination is a serious but prevalent type of behavioral delay, especially among college students, associated with negative outcomes like stress and poor grades. Recently however, researchers have proposed the existence of a type of behavioral delay that is beneficial, called strategic delay. The purpose of this study was to explore how people who strategically delay experience and deal with stress in their daily lives. This was rooted in the lack of research exploring the potentially negative effects of strategic behavior, which is needed since strategic delay is considered to be a beneficial study strategy. This study sought out to answer two questions: (i) was there a significant correlation between strategic delay and perceived stress, and (ii) how much of the variance in perceived stress could be explained by strategic delay. To answer the two questions a paper survey study was conducted. The survey consisted of New Procrastination Scale (measured perceived stress), Perceived Stress Scale 10 (measured perceived stress), and background questions. The results from the data analysis showed that strategic delay correlates significantly, moderately and negatively with perceived stress (r[99] = -0,314, p<0,001). Strategic delay explained 8.9 percent of the variance in perceived stress. An ANOVA showed that the explained variance was significant (F[1,97] = 10,612, p<0,002). There were quite a few methodological issues with study. The most serious one was the translation of NAPS, which was in many ways far from well executed. This hurt the scale’s as well as the study’s reliability and validity. The results from this study should therefore be interpreted carefully.

Syftet var att undersöka högkänslighet och stress hos studenter. Metoden var en kvantitativ jämförande studie mellan grupper (kvinnor och män). Undersökningen genomfördes genom en elektronisk enkät. Urvalet var ett tillfällighetsurval av kvinnor och män i åldrarna 19 – 56 som studerade vid ett universitet, totalt 122 stycken deltagare, 31 män och 91 kvinnor. Deltagarna besvarade en enkät som bestod av bakgrundsfrågor och mätinstrument som mätte stress och högkänslighet. Resultatet visade på att högkänslighet och stress var skattad högst bland kvinnorna. Slutsatsen är att kvinnor och män skiljer sig i högkänslighet och stress samt att stress och högkänslighet korrelerar med varandra. / The aim was to investigate high sensitivity and stress among students. The method was a quantitative comparative study between groups (women and men). The survey was conducted through an electronic questionnaire. The selection was an opportunity sample of women and men who studied at a university and was between the ages of 19-56, a total of 122 participants 31 men and 91 women. The participants answered a questionnaire that consisted of background questions and instruments to measure stress and high sensitivity. The results showed that high sensitivity and stress was underestimated highest among women. The conclusion is that women and men differ in high sensitivity and stress, and that stress and high sensitivity correlate.

On constate une forte demande mondiale d' énergie propre et renouvelable en raison de la consommation rapide des combustibles fossiles non renouvelables et l'effet de serre qui en résulte. Une solution prometteuse pour produire une énergie propre et renouvelable est d'utiliser des cellules solaires pour convertir l' énergie solaire directement en électricité. Comparativement à leurs homologues inorganiques, les cellules solaires organiques (OSCs) sont maintenant intensivement étudiées en raison des avantages tels que le poids léger, la flexibilité, la compatibilité avec les procédés de fabrication à faibles coûts. Malgré ces avantages, l'efficacité de conversion (PCE) des OSCs doit encore être améliorée pour la commercialisation à grande échelle. Les cellules solaires organiques sont réalisées en pile de couches minces comprenant des électrodes, la couche de transport d' électrons, la couche de polymère actif et la couche de transport de trous. Dans cette étude, nous sommes concernés par la couche de PEDOT:PSS qui est couramment utilisée comme une couche tampon entre l'électrode anodique et la couche de polymère actif de cellules solaires organiques. Cette étude vise à intégrer différentes concentrations de nanoprismes (NPSMs) d'argent de taille sub-longueur d'onde dans du PEDOT: PSS afin de profiter de leurs propriétés optiques uniques nées de résonances de plasmons de surface localisées (LSPR) pour améliorer la collecte lumineuse et l'efficacité de génération de charge en optimisant l' absorption et la diffusion de la lumière. Nous avons constaté que les facteurs clés qui contrôlent les performances des cellules solaires plasmoniques comprennent non seulement les propriétés optiques, mais également les propriétés structurelles et électriques des couches hybrides de PEDOT:PSS comprenant des NPSMs d' Ag. D'une part, l'ajout de NPSMs d' Ag conduit ¨¤ (1) une augmentation de l'absorption optique; (2) de la diffusion de la lumière ¨¤ de grands angles ce qui pourrait conduire ¨¤ un meilleur piégeage de la lumière dans les OSCs. D'autre part, (1) la rugosité de surface est augment¨¦e en raison de la formation d'agglomérats de NPSMs d' Ag, ce qui conduit ¨¤ une meilleure efficacité de collecte de charge; (2) la résistance globale des films hybrides est également augment¨¦e en raison de l'excès de PSS introduit par les NPSMs d' Ag incomplètement purifiées, inférieur courant de court-circuit (Jsc) qui en résulte; (3) les Ag NPSMs et leurs agglomérats ¨¤ l'interface PEDOT:PSS/couche photo-active pourraient agir comme des centres de recombinaison, conduisant ¨¤ une réduction de la résistance de shunt, du Jsc et de la tension en circuit ouvert (Voc). Afin de résoudre partiellement l'inconvénient (2) et (3), en intégrant des NPSMs d¡¯Ag davantage purifiés et une petite quantité de glycérol dans le PEDOT:PSS, la résistance des couches hybrides de PEDOT:PSS-Ag-NPSMs peut ¨être réduite à une valeur comparable ou inférieure ¨¤ celles couches vierges. Les futurs progrès en chimie de surface colloïdale et l'optimisation sur le processus d'incorporation des nanoparticules seront nécessaires pour produire des cellules solaires organiques plasmoniques de meilleures performances. / Nowadays there has been a strong global demand for renewable and clean energy due to the rapid consumption of non-renewable fossil fuels and the resulting greenhouse effect. One promising solution to harvest clean and renewable energy is to utilize solar cells to convert the energy of sunlight directly into electricity. Compared to their inorganic counterparts, organic solar cells (OSCs) are now of intensive research interest due to advantages such as light weight, flexibility, the compatibility to low-cost manufacturing processes. Despite these advantages, the power conversion efficiency (PCE) of OSCs still has to be improved for large-scale commercialization. OSCs are made of thin film stacks comprising electrodes, electron transporting layer, active polymer layer and hole transporting layer. In this study, we are concerned with PEDOT:PSS layer which is commonly used as a buffer layer between the anodic electrode and the organic photoactive layer of the OSC thin film stack. We incorporated different concentrations of silver nanoprisms (NPSMs) of sub-wavelength dimension into PEDOT:PSS. The purpose is to take advantage of the unique optical properties of Ag MPSMs arisen from localized surface plasmon resonance (LSPR) to enhance the light harvest and the charge generation efficiency by optimizing absorption and scattering of light in OSCs. We found that the key factors controlling the device performance of plasmonic solar cells include not only the optical properties but also the structural and electrical properties of the resulting hybrid PEDOT:PSS-Ag-NPSM-films. On one hand, the addition of Ag NPSMs led to (1) an increased optical absorption; (2) light scattering at high angles which could possibly lead to more efficient light harvest in OSCs. On the other hand, the following results have been found in the hybrid films: (1) the surface roughness was found to be increased due to the formation of Ag agglomerates, leading to increased charge collection efficiency; (2) the global sheet resistance of the hybrid films also increases due to the excess poly(sodium styrenesulphonate) introduced by incompletely purified Ag NPSMs, resulting in lower short circuit current (Jsc); (3) the Ag nanoprisms and their agglomerates at the PEDOT:PSS/photoactive layer interface could act as recombination centers, leading to reductions in shunt resistance, Jsc and open circuit voltage (Voc). In order to partially counteract the disadvantage (2) and (3), by incorporating further purified Ag NPSMs and/or a small amount of glycerol into PEDOT:PSS, the sheet resistance of hybrid PEDOT:PSS-Ag-NPSM-films was reduced to a resistance value comparable to or lower than that of pristine film.

Bakgrund: Stress kan definieras som ett mått av en individs interaktion med dennes omgivning. En väl individanpassad miljö ger bättre förutsättningar för att uppleva en låg stress och kunna hantera stressfaktorer på ett för individen mer adekvat sätt. Husdjur kan skapa positiva känslor och reducera stressreaktioner och därmed även påverka individens hälsa positivt. Syfte: Syftet var att undersöka självupplevd stress hos vuxna samt analysera om det finns skillnader i självupplevd stress och hantering avseende om individen har husdjur eller inte. Metod: En enkätstudie delades ut via sociala medier. 112 individer besvarade frågor om upplevd stress med Perceived Stress Scale - 14 samt sju bakgrundsfrågor, utformade för att kunna besvara tvärsnittsstudiens syfte. Resultat: Ingen signifikant skillnad kunde påvisas i de totala stress- och hanteringsnivåerna hos respondenterna relaterat till om de ägde husdjur eller inte. 91,14% (n=72) av husdjursägarna ansåg att deras husdjur hade en positiv inverkan på deras självupplevda stress. Husdjursägarnas hanteringsnivå av stress var signifikant (p=0,016) bättre om respondenten hade en positiv inställning till att äga husdjur. Av dem som inte ägde husdjur menade signifikant (p=0,019) fler deltagare att upplevelsen av att äga ett husdjur skulle vara positiv. Andelen kvinnor och heltidsarbetande bland respondenterna var övervägande. Resultatet av analysen visar att den övervägande delen av samtliga deltagare upplevde en låg total stressnivå (p=0,027). Diskussion: Att som distriktssköterska kunna uppmuntra patienter till att skaffa ett husdjur, besöka/vara nära ett djur eller ordinera ett assistansdjur/vårddjur, skulle kunna bidra till en förbättrad psykisk och fysisk hälsa hos patienten. Slutsats: Att ha ett husdjur inverkar positivt på den självupplevda stressen. Resultatet från denna studie kan användas i omvårdnadspraxis genom en uppmuntran till att ha närhet till djur i förebyggande och rehabiliterande/stressreducerande syfte. / Background: Stress can be defined as a measure of an individual's interaction with their environment. A well-adapted environment provides better conditions for experiencing low stress and being able to manage stress factors in a way that is more adequate for the individual. Pets can create positive emotions and reduce stress reactions and thus also affect the individual's health positively. Aim: The aim was to investigate self-perceived stress in adults and analyze whether there are differences in self-perceived stress and management regarding whether the individual has pets or not. Method: A questionnaire study was distributed via social media. 112 individuals answered questions about perceived stress with Perceived Stress Scale - 14 and seven background questions, designed to be able to answer the purpose of the cross-sectional study. Results: No significant differences could bedetected in the total stress and stress management levels of the respondents related to whether they owned pets or not. 91.14% (n = 72) of the pet owners considered that their pets had a positive impact on their self-perceived stress. The pet owners' level of stress management was significantly (p = 0.016) better if they had a positive attitude towards owning pets. Of those who did not own a pet, significantly (p = 0.019) more participants thought that the experience of owning a pet would be positive. The proportion of women and full-time workers among the respondents was predominant. The results of the analysis show that the vast majority of all participants experienced a low total stress level (p = 0.027). Discussion: Being able to encourage patients as a district nurse to acquire a pet, visit/be close to an animal or prescribe an assistance animal/care animal, could contribute to an improved mental and physical health of the patient. Conclusion: Having a pet has a positive effect on self-perceived stress. The results from this study can be used in nursing practice through an encouragement to be close to animals for preventive and rehabilitative/stress-reducing purposes. / <p>Godkännandedatum: 2021-12-06</p>