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Introduktion/Bakgrund: COVID-19 en zoonotisk och mycket smittsam sjukdom som har haft en stor påverkan på hälso- och sjukvården internationellt. Antalet inrapporterade fall konstaterat med COVID-19 har sedan den 6 september 2021 resulterat i 218 946 836 bekräftade fall och 4 539 723 dödsfall. Syfte: Sjuksköterskans upplevelser från COVID-19 pandemin på sjukhus. Metod: Litteraturstudien utformas utefter Polit & Becks (2020) nio steg. Databassökningar genomfördes i CINAHL och PubMed. Tolv artiklar svarade mot syftet samt inklusions- och exklusionskriterierna för studien. Artiklarna granskades utifrån Polit & Becks (2020) kvalitativa och kvantitativa granskningsmallar. Resultat: Fyra kategorier formades utifrån sjuksköterskornas upplevelser: Rädslan för sjukdomen, Ovisshet och professionsutveckling, Hälsopåverkan och utmattning samt Betydelsen av stödet. Slutsats: Sjuksköterskans upplevelser från COVID-19 pandemin bestod av både psykiska och fysiska påverkanden. Det fanns en känsla av otillräcklighet när det kom till yrkesrollen med ett bristande stöd från ledningen. Trots många brister upplevde många sjuksköterskor en positiv uppmuntran från samhället och en stark laganda, vilket förde professionen framåt och stärkte självförtroendet för individen att kunna hantera den pågående COVID-19 pandemin.

This report investigates the possibility of simulating a fiber composite plate with embedded piezoelectric transducers connected to shunt circuits in order to control vibration. The simulation model is validated in steps of discipline, both analytic and experimentally. First the piezoelectric material used is studied where comparisons are done between analytic and numerical results to ensure electromechnical coupling. Next the interaction with structures are studied by bonding piezoelectric transducers to an aluminum cantilever and study the structural response, where numerical results are compared to experimental data. Piezoelectric shunt damping is studied by connecting a tuned shunt circuit to a piezoelectric transducer, the results from the simulation model are then compared to experimental data where an attenuation of 12 dB is experimentally verified for the first mode. Lastly, all aspects above are implemented in a simulation model to estimate structural behavior of an arbitrary fiber composite plate with embedded piezoelectric transducers. The software used for numerical finite element simulation is Comsol Multiphysics 5.2.

The fire resistance of a sprayed concrete inner lining for tunnels has been investigated experimentally and theoretically. During the initial first test on a section of nominal size 5 × 3 × 0.12 m3 the specimen maintained the integrity and insulation criteria during 180 minutes fire exposure with the Hydrocarbon fire curve. Also during the second test, where two specimens of half the size were tested, the integrity and insulation criteria’s were maintained but during this test the fire exposure was reduced during a period of the test due to a technical malfunction. The thermal properties of the sprayed concrete was shown by TPS measurements to be in the span of the values found in the Eurocode. Further on, calculations based on the Eurocode model including temperature dependent stress/strain was shown to give results on the safe side compared with measurements performed during the test. Stresses calculated in the supporting steel bars were 2 to 3 times higher than the measurements which is conservative. Key words: tunnels, fire, sprayed concrete

This report is written in the purpose to investigate the mechanical forces and characteristics related to a propeller driven aircraft in the Earth’s atmosphere. It’s written as a thesis project during the spring semester of 2014 and graded accordingly. Thanks Arne Karlsson for fruitful discussions. Also thanks to Simon Leijonmarck for help with useful discussions concerning structural batteries. Denna rapport är skriven i ändamålet att undersöka de mekaniska krafter och egenskaper som rör ett propellerdrivet flygplan i jordens atmosfär. Den är skriven som ett examensarbete under vårterminen 2014 och betygsätts därefter. Tack Arne Karlsson för givande diskussioner. Även tack till Simon Leijonmarck för hjälp med givande diskussioner rörande strukturella batterier.

Fire spalling of concrete is not a new phenomenon. To some degree there has always been a risk during rapid heating of concrete. Therefore, to a certain degree the effect of fire spalling is included in the bank of data from fire tests and fires on which our understanding of the fire resistance of concrete is based. However, the development and modern use of more dense concrete mixes have produced cases of very severe fire spalling which have increased the urgency to understand this phenomenon. In this context, the use of an addition of polypropylene (PP) fibres to the mix to limit the amount of spalling has been one topic of interest for this thesis. During fire tests on a post-tensioned concrete structure made of spalling sensitive concrete, it has been shown that substantially lower amounts of PP fibres than 2 kg/m3, which is recommended in the Eurocode (1992-1-2:2004), can be used with successful results. As part of this study, another important aspect has emerged, i.e. the impact the test method used can have on the fire spalling depths observed in concrete specimens. This has been known for many years but is seldom discussed in the scientific literature. In this thesis it has been shown that results from tests on unloaded cubes do not necessarily correspond to results seen on larger loaded slabs. In the results presented, none of the tested cubes spalled whereas some of the large slabs spalled to the degree that the reinforcement became fire exposed. Further, the difference in spalling depths between small and large post-tensioned slabs was shown to be substantial; although in general the ranking in severity from least to greatest spalling correlated between these two specimen sizes. The correlation to larger specimens was much vaguer in the case when the small slabs were not loaded in compression as there sometimes was no spalling in the small slabs. From time to time the randomness of the fire spalling of concrete has been mentioned. To investigate this further, an analysis of 110 fire tests performed on small slab type specimens was performed. This analyse showed that the spalling behaviour had a good repeatability between two identical tests, which proved that the so called “random factor” relating to spalling depth was low for the chosen data set. It was also possible to make a multiple least squares fit of test parameters that could be used to predict the spalling behaviour which also underlines that a substantial stochastic factor was not present. Regarding the influence of different factors, the results compiled on the influence of ageing show that for three of the tested Self-Compacting Concrete (SCC) mixes, the amount of spalling was reduced with age whereas for the fourth mix (which included the highest amount of limestone filler, 140 kg/m3) the spalling was not reduced with age. In this test series no systematic influence of the intensity of the fire, between standard fire exposure and the more severe hydrocarbon fire, on the spalling depth was detected for this type of specimen. The only major difference was that spalling started earlier during the more severe fire exposure. Pressure measurements conducted as part of the work within this thesis, supported by results from the literature, indicate that there is no relationship between pressure rise due to moisture and fire spalling. Based on this and the fact that the spalling event in many cases happens at relatively low temperatures where the saturation vapour pressure is low two alternative factors to explain the function of PP fibres have been presented: (i) PP fibres reduce the moisture content in the critical zone close to the heated surface which affects the mechanical properties advantageously, and (ii) PP fibres amplify moisture movement leading to larger drying creep and shrinkage which locally relax the thermal stresses. To investigate the influence of the presence of moisture on the compressive strength, specimens were tested after being boiled for varying periods of time in a water bath. The study showed a remarkable reduction of strength due to boiling of the mortar specimens. After boiling mortar in a water bath for 3, 10 or 20 minutes, i.e. approximately the same time span as the initiation of fire spalling during fully developed fires, the strength was only 64% of the corresponding value for a dry specimen. As no strength change was detected between the specimens boiled 3, 10 or 20 minutes, and that the corresponding saturation pressure for steam at 100ºC is negligible compared with the tensile strength of concrete, it was concluded that pore pressure is not a significant contributor to the measured reduction in strength. It appears that the presence of moisture itself rather than an increased pressure is the most important factor reducing strength. This is a clear indication that moisture plays a key role in the fire spalling of concrete but in a different way from previously assumed. QC 20130911

Godkänd; 2010; 20100827 (pinzha)

Despite almost 100 years of research, the fundamentals of fire spalling of concrete are not yet fully understood. Many different theories exist, each trying to describe the coupling between different phenomenon leading to fire spalling. Some of these phenomenon have been investigated and are presented in this thesis. The thermal properties at high temperature have been investigated using the Transient Plane Source (TPS) technique. Measurements of temperature in the cross-section of selfcompacting concrete with the addition of polypropylene fibres (PP-fibres) during fire exposure are presented. A verification calculation, based on the measured values of temperature in the cross-section of the fire exposed concrete, was compared with results from a full-scale fire test with the same concrete. Good correlation was obtained. Using a measurement system consisting of oil filled steel pipes, the pressure inside the concrete during fire exposure, was measured. Results from pressure measurement tests on self compacting concrete show relatively low internal pressure before spalling. In fact, the pressure was highest in a specimen that did not spall during fire exposure. Conclusions from the tests were that pore pressure only played a secondary role in the spalling process of the concrete investigated. Thermal stresses were believed to be the primary reason for spalling. With a small addition of polypropylene fibres (PP) in concrete the fire spalling can be limited or totally avoided. Comparative studies of concrete with and without PP- fibres were performed, and the function of PP-fibres was illustrated in small and large scale fire tests. When determining the free thermal expansion as a function of temperature a strain plateau was found in specimens containing PP-fibres. The plateau corresponds fairly well with the temperature where accelerated drying behaviour was shown. This is an indication that an accelerated drying creep phenomenon might be present. Further experimental work is needed to verify this postulate.

Sammanfattning Syfte och frågeställningar Syftet med studien har varit att undersöka vilka som väljer att studera till lärare i idrott och hälsa samt till tränare på Gymnastik- och idrottshögskolan i Stockholm. • Hur ser studenternas bakgrund (ålder, kön, bostadsort, social bakgrund, invandrarbakgrund och idrottslig bakgrund) ut? • Varför valde studenterna att studera på GIH i Stockholm, och på vilka antagningsgrunder blev de antagna? Metod I studien deltog 83 studenter, varav 35 stycken från tränarprogrammet och 48 stycken från lärarprogrammet. Studenterna svarade på en enkät som tog upp frågor rörande studenternas bakgrund och studieval. Enkätsvaren bearbetades sedan i SPSS där signifikansnivån sattes till p

På uppdrag av Lidingöstad har en undersökning av gamla Lidingöbrons nuvarande tillstånd inletts. Uppdraget har gått till Carlbro AB, Stockholm som har anlitat Institutionen för byggvetenskap vid KTH för att utföra töjningsmätningar vid tågpassage över bron vilka gjordes under början av oktober 2003, [1]. Detta examensarbete gjordes i samband med dessa undersökningar. Lidingöbron är i huvudsak en fackverksbro med i regel 50 m spannindelning med undantag av ett bågspann och ett längre fack på 70 m. Den har en totallängd på ca 730 m. Lidingöbron togs i bruk 1925. Den var ursprungligen dimensionerad för att bära järnvägs-, spårvägs-, landsvägs-, cykel- samt gångtrafik. Trafikintensiteten på bron ökade kraftigt under årens lopp då den tjänade som Lidingös enda permanenta förbindelse till fastlandet. Under åren har flera olika renoveringar och ombyggnader gjorts, den senaste 1986. Trafiken är idag mindre än tidigare med spår på ena sidan och gång- och cykelväg på andra sidan mot tidigare dubbelspår. Vid byggnationen förväxlades de olika stålsorterna i fackverket. Bristfälligt stål användes på konstruktiva delar och flera bristfälliga reparationer har gjorts. Bron har till dags dato använts i snart 80 år och bedöms vara i relativt dålig kondition. Den har utsatts för ett stort antal på- och avlastningar med motsvarande stora spänningar. Lidingöbron har fyllt en viktig funktion för lidingöborna och flertalet undersökningar av alla brons delar har tidigare genomförts. Avsikten med undersökningen är att fastställa stålets nuvarande kondition samt att föreslå eventuella åtgärder för brons fortlevnad. Till grund för skattningen av brons kvarvarande livslängd ligger töjningsmätningarna som gjorts på i förväg valda balkar. Intressant är hur stora spänningar dagens belastning ger upphov till samt vilken spänningsvidd som råder. I undersökningen kommer även en likadan studie med mätningar som ska utföras under kommande vinter. Detta examensarbete syftar till att i första hand ta fram en pålitlig finit elementmodell av gamla Lidingöbron. Som underlag har original- och renoveringsritningar och egna mätningar från byggställning använts. Ritningarna finns hos tekniska kontoret och arkivet på Lidingö kommun. En kalibrering av modellen har gjorts med hjälp av de data som fåtts från de töjningsmätningar som gjorts. Bron består av flera leder och fogar vilka kan misstänkas ha bristande funktion. Därtill görs en undersökning av vad vinterförhållanden skulle kunna innebära. Modellen har begränsats till att omfatta en del av bron, med start från bågspannet till landfästet på Lidingö. Modellen som tagits fram över Lidigöbron, har vid jämförelse med de aktuella töjningsmätningarna och en tidigare undersökning av bron från 1967 visat att modellens resultat överensstämmer väl med dessa. En liten avvikelse från töjningsmätningarna uppträder i fackverket på gångbanesidan. Denna skillnad beror på att gångbanan styvar upp konstruktionen, vilket leder till att spänningarna i modellen blir något större på den sidan. Med detta i beaktande har FE-modellen används för att göra ytterliggare undersökningar av Lidingöbrons tillstånd. Inga av de beräkningar som gjorts med hjälp av SOLVIA har visat på så stora spänningar att det aktuella stålets flytgräns uppnås. By order of the city of Lidingö has an examination being started to determine the current state of the old Lidingö bridge, citied just outside the city of Stockholm. The assignment went to Carlbro AB, Stockholm. They have engaged the department of structural engineering at the Royal Institute of Technology to perform measurements of the stresses during the crossing of trains. The measurements were made in the beginning of October 2003, [1]. This master thesis has been made in addition to these measurements in purpose to develop a finite element model of the bridge. The Lidingö bridge is mainly a truss bridge with in general 50 m spans with the exception of an arc span and a longer span of 70 m. The bridge has a total length of approximately 730 m. The Lidingö bridge began to be used in 1925. It was originally dimensioned for railroad-, tramway- and car traffic and bicycles and pedestrians. The traffic intensity on the bridge increased over the years when it served as the only permanent connection to the mainland. Over the years have many renovations and rebuildings been made, the latest in 1986. The traffic today is less than it once was with rails on one side and pedestrians and bicycles on the other, when it earlier was a double railroad. During the construction were there confusions between the different types of steel in the framework. Insufficient steel was used in constructive parts and several reparations have been made to correct this error. The bridge has to this day been used for nearly 80 years and is assumed to be in relatively bad condition. It has been exposed to a large amount of on- and off loadings with high stresses. The Lidingö bridge has filled an important function for the island and several examinations have earlier been made to ensure its state. The purpose of the examination is to determine the steels present condition and to present measures for its future use. As a base for the determination of the bridges future lies the stress measurements which has been made in choosed beams. Interesting is how high stresses and stress spans there is under to days load. The examination also involves future measurements under the coming winter. This master thesis aims primarily to develop a reliable finite element model of the bridge. The model is based on original- and renovation drawings and self made measurements from platforms. The drawings are located in the technical office and the city archive, both citied on Lidingö. The model has been refined with help from the measurements of the stresses. The bridge has a couple of hinges and joints which can have insufficient condition. In addition to that there is a simulation of how winter state effects the beams. The model is limited to the part starting from the end of the arc span and ends at the abutment on Lidingö, Figure 1.1. The results from the model have shown good correspondence to the strain measurements and an earlier examination done in 1967. A small difference appears on the pedestrian side. It could be explained with the fact that the superstructure stiffens the construction which leads to larger stresses on that side. With that in mind has the model been used to make further examinations of the Lidingö bridges condition. The made calculations in SOLVIA has not shown any stresses close to the steels yield point.

A1210 Teknisk aktieanalys används för att från historiska kursdata försöka förutsäga den framtida kursutvecklingen. Uppsatsens syfte är att undersöka börstrendens inverkan av resultaten för två olika tekniska analysmodeller, glidande medelvärde och Relative Strength Index (RSI). Som dataunderlag används 12 aktier från Stockholmsbörsens A-lista för Mest omsatta aktier mellan 1988-03-01 och 2004-03-01. I studien tillämpas blankning för att oberoende av den rådande trenden ha möjlighet att generera överavkastning. Överavkastningen undersöks genom att riskjustera avkastningen med Capital Asset Pricing Model (CAPM). Vidare belastas varje transaktion med en courtageavgift. Det visar sig att endast köpsignalerna är statistiskt signifikanta. Följden blir att det endast är möjligt att generera statistiskt signifikant överavkastning under perioder med uppåtgående trender. Därmed har trenden inverkan för de undersökta analysmodellerna. För modeller som genererar väldigt många signaler påverkas resultatet kraftigt negativt av courtageavgifter. Den högsta överavkastningen (årlig överavkastning på 33,1 procent) fås för ett dubbelt glidande medelvärde med perioderna 5 och 150. För att med väldigt hög sannolikhet generera positiv överavkastning skall köp- och säljsignaler från denna metod på en diversifierad portfölj strikt följas under åtminstone en 8 årsperiod.

An investigation of the TPS (Transient Plane Source) method to determine the thermal properties for building materials at high temperature has been performed. The thermal conductivity, diffusivity and the volumetric specific heat for different building materials at room temperature and at elevated temperatures has been determined. Also influence of moisture content on the thermal properties of a number of materials was instigated.