The presence of magnetic fields has increased significantly during the last hundred years due to technology development and increased consumption of electricity. Sweden follows recommended maximum values from the International Commission on Non-Ionizing Radiation Protection (ICNIRP), which are to prevent acute effects and are generally not exceeded in the environment. For long-term effects, such as increased cancer risk, today's knowledge is not sufficient to establish any limit values. The study aims to determine the variation of daily exposure of low-frequency magnetic fields in individuals with different occupations and living environments. Measurements of low-frequency magnetic fields were performed with an EMDEX-meter to get a 24-hour magnetic field exposure for ten test subjects. Measurement with an SMPS-meter was performed to measure magnetic fields at some common objects in the home environment that emit low frequency magnetic fields. The average value for exposure of low-frequency magnetic fields for 24-hours varied between 0.03–0.10 µT, exposure in the home environment varied between 0.00–0.17 µT, working environment varied between 0.02–0.27 µT, night environment varied between 0.00–0.09 µT. The daily mean values from the measurements are at what can be regarded as a normal exposure 0.01–0.20 µT. The average value that was picked up from home-, joband night-environment can be considered as normal exposure level. Based on the increased presence of electronics and magnetic fields and the lack of knowledge in the research on health effects, it may be interesting to discuss the introduction of further new technology, limit values, safety and supervision.

Background: In the early 1980s, the use of the magnetic resonance imaging (MRI) in medical diagnostics increased. MRI examination is considered a safer method than the use of ionizing radiation. But there are some risks connection to with MRI examinations, for example, the strong magnetic field can affect ferromagnetic objects in the MR examinations room which may become projectiles. During MRI examinations, the safety for both patients and staff is of high importance. The radiographer is responsible for the safety associated with MRI examinations; this is possible by having knowledge about the safety routines. Purpose: The purpose of this study was to investigate how radiographers experience their work in MRI environment. Method: Materials for this study were collected through interviews with four radiographers at two different MRI units. The interviews were analyzed by a manifest content analysis. Result: Three main categories were defined: the experience of collaboration; the experience of routines and the experience of need for development. All the participants felt safe and secure working in the MRI environment since they had good communication with each other and safety routines. The interaction with each other was a way to prevent accidents and injuries during the MRI examination. To be able to feel higher secure and safety in this environment, more understanding and knowledge from other staff from units were something the participants wanted.

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För att kunna bedriva forskning i det nybyggda rummet på Karolinska Universitetssjukhuset vid Rosenlunds Sjukhus krävs det att magnetfäl- tet valideras. Detta är av vikt att undersöka för att kontrollera om det finns möjlighet att installera en teleslinga, samt säkerställa att mag- netfältet som genereras från högtalarna inte blir för stort för framtida forskning på bland annat hörapparater med telespole. Magnetfältsnivån mättes i tomt rum och med inkopplade högtalare som genererade ett monotont ljud motsvarande talstyrkan hos en vux- en man. Bakgrundsmagnetfältet var i det stora hela inom gränsvärdena givna av IEC 60118-4 bortsett från ett fåtal mätpunkter. Vid högtalarmät- ningarna visade det sig däremot att flertalet mätpunkter intill högta- larna inte höll sig inom gränsvärdena. Magnetfältet, som genererades av strömmen till högtalarna, avtog snabbt med avståndet. Detta med- för att högtalarnas placering är av betydelse och att det bör tas hänsyn till. / To perform research in a new room at Karolinska University Hospital, Rosenlund Hospital, it has to be validated regarding to magnetic field. This is of importance to verify if it is possible to install a hearing loop, as well to make sure that the magnetic field generated from the speak- ers does not cause problems at future research regarding for example hearing aids with a telecoil. The magnetic field level was measured in the room when it was empty and with connected speakers generating a monotonous sound corre- sponding the speech level from a grown man. The background magnetic field level was mainly within the limits given by IEC 60118-4 aside from a few measuring points. The measurements with speakers connected showed that several measuring points close to the speakers were not within the limits. Although the magnetic field, generated by the current to the speakers, decreased rapidly with dis- tance. The placement of the speakers are therefore significant and have to be accounted for.

Det har tidigare uppmärksammats att magnetfältsnivåerna kan vara relativt höga i kuvöser, framförallt på grund av den värmebädd som barnet ligger på. I epidemiologiska studier av barnleukemi och association till magnetfältsexponering har man funnit en antydan till överrisk bland för tidigt födda barn som legat i inkubatorer med höga magnetfältsnivåer. Man har även funnit påverkan på hjärtfrekvensvariabilitet hos barn som vårdats i kuvöser och här misstänker man förhöjda magnetfältsnivåer som en möjlig förklaring. Syftet med denna studie var att genom noggranna mätningar kartlägga lågfrekventa magnetfält i och kring två sorters kuvöser (Dräger 8000 IC och Giraffe OmniBed) samt kringutrustning till dessa. Vidare har långtidsregistreringar av magnetfältet utförts i båda kuvöstyperna. I den äldre kuvösmodellen, Dräger 8000 IC, uppmättes värden mellan 1.0 och 8.1 µT vid kartläggning av magnetfältet inne i kuvösen. De högsta värdena var lokaliserade ovanför värmeelementet, en bit från centrum av kuvösen. Magnetfältet i den nyare modellen, Giraffe OmniBed, varierade vid kartläggningen mellan 0.2 och 5.8 µT, där de högsta värdena uppmättes mot ena kortändan av kuvösen. Medelvärdet från långtidsregistreringarna i kuvöserna beräknades till 1.9 µT för Dräger-kuvösen och 0.2 µT för Giraffe-kuvösen. Medelvärden från långtidsregistreringarna användes även till att beräkna en medeldos för sju veckors heltidsvård av barn i kuvös, uttryckt i mikroteslatimmar. Medeldosen för Dräger blev för huvudet 2.9∙103 µT∙h och för resten av kroppen 2.4∙103 µT∙h. För Giraffe blev medeldosen för huvudet 4.4∙102 µT∙h och för resten av kroppen 2.7∙102 µT∙h. Långtidsregistrering av magnetfält i hemmiljö mättes också i ett äldre hus och i en nyare lägenhet för jämförelse. Medeldosen för sju veckor i hemmiljö blev 10 – 60 µT∙h. Sammanfattningsvis kan man konstatera att magnetfälten i den nyare kuvösen (Giraffe OmniBed) var betydligt lägre än för den äldre kuvösmodellen (Dräger 8000 IC), men är fortfarande något förhöjda jämfört med normal hemmiljö. / It has previously been observed that the magnetic fields in infant incubators can be relatively high, particularly due to the heating bed the child is lying on. In epidemiologic studies of childhood leukaemia in association with exposure to magnetic fields, an inclination to excess risk has been found amongst premature children that have been lying in infant incubators with high magnetic field levels. Influence on the heart rate variability has also been found in children that have been treated in incubators, where elevated magnetic field levels are seen as a possible explanation. The purpose of this study was to map the magnetic field exposure in two different infant incubators (Dräger 8000 IC and Giraffe OmniBed) and the peripheral equipment. Furthermore, the magnetic field was logged over time in both incubator models. In the older model, Dräger 8000 IC, magnetic field levels between 1.0 µT and 8.1 µT were measured during the mapping of the magnetic field distribution over the bed. The highest value was localized above the heater, a short distance from the centre of the bed. The magnetic field in the newer model, Giraffe OmniBed, varied between 0.2 µT and 5.8 µT during the mapping, where the highest value was localized towards one of the short ends of the incubator. The mean value from the long term registration was calculated to 1.9 µT for the Dräger incubator and 0.2 µT for the Giraffe incubator. The average magnetic field level from the long-term registrations was used to calculate a dose for the baby, expressed in microtesla hours. The average dose for seven weeks of full time treatment in an incubator was 2.9∙103 µT∙h for the head and 2.4∙103 µT∙h for the remaining body in the Dräger incubator. Corresponding values for the Giraffe incubator was 4.4∙102 µT∙h for the head and 2.7∙102 µT∙h for the body. Long-time registration in home environment was also conducted in an older house and in a newer apartment. The average dose for seven full weeks was then 10 – 60 µT∙h. The conclusion from all this is that the magnetic field levels in the newer incubator model (Giraffe OmniBed) was significantly lower than in the older model (Dräger 8000 IC) but still higher than in an average home environment.

<p>This report describes the design and construction of a prototype that automatically aims a microwave link towards a target. The link, that is located on a mobile aerial mast, is used by Saab Training Systems as a part of an infrastructure network. The report also discusses the development of a GUI that communicates with the control unit by Bluetooth.</p><p>The control unit, called Pan/Tilt-controller, controls the position of the link by stepping motors. One motor controls the azimuth angle and the other one controls the elevation angle.</p><p>By a GUI the operator enters the coordinates on its own position and the targets position. Hereafter a bearing is calculated and it will be sent up to the control unit.</p><p>The control unit will sense its own direction by a magnetic sensor that works as an electronic compass. The Pan/Tilt-controller will then rotate the link to reach the targets coordinates. Alternatively you can control the position of the link manually by the GUI.</p><p>The report also discusses the functionality of the sensors and tests have been conducted to determine the accuracy of the control unit. The Pan/Tilt-controller can rotate a link 360º around its own axis and also tilting the link ±90º. The Pan/Tilt-controller can direct a link towards a target with an accuracy of 5º -10º.</p>

This report describes the design and construction of a prototype that automatically aims a microwave link towards a target. The link, that is located on a mobile aerial mast, is used by Saab Training Systems as a part of an infrastructure network. The report also discusses the development of a GUI that communicates with the control unit by Bluetooth. The control unit, called Pan/Tilt-controller, controls the position of the link by stepping motors. One motor controls the azimuth angle and the other one controls the elevation angle. By a GUI the operator enters the coordinates on its own position and the targets position. Hereafter a bearing is calculated and it will be sent up to the control unit. The control unit will sense its own direction by a magnetic sensor that works as an electronic compass. The Pan/Tilt-controller will then rotate the link to reach the targets coordinates. Alternatively you can control the position of the link manually by the GUI. The report also discusses the functionality of the sensors and tests have been conducted to determine the accuracy of the control unit. The Pan/Tilt-controller can rotate a link 360º around its own axis and also tilting the link ±90º. The Pan/Tilt-controller can direct a link towards a target with an accuracy of 5º -10º.

The assignment is issued by Scania Maintence AB seeking a new approach to detect power changes in their industrial processes. The work has taken place at Ångströmslaboratoriet and tests have been performed at Scania AB Södertälje. Today’s society consumes enormous amount of energy. In both economically and environmental view, it is important that the processes are effective, with high power factor. There are many ways to measure power in the industry, what they all have in common is that the installation is advanced, requires time and planning. Only a competent electrician may install the measuring device in the distribution box. The purpose of the project is to build a prototype for power measurement that can be easily used outside the distribution box, thus simplifying the procedure and shortening the time required. By attaching sensors around the supply cable, the magnetic field asymmetric flux density can be used and induce voltage proportional to the current in the cable. The result is an instrument that with a computer calculates current, phase angle and power. Measurements of the current rms value showed that the maximum difference between our prototype and Scania Maintenances equipmentis up to 29 percent. However, for a longer time (&gt; 15 minutes) the differences between the mean values are only 1.2 percent and the accuracy is calculated to +/-3.67A with 95% confidence intervals. Phase angle accuracy measured to plus 6 minus and 15 percent. / Uppgiften är utfärdat av Scania Maintenance AB som söker en ny metod för att se effektförändringar i deras industriprocesser. Arbetet har ägt rum i Ångströmlaboratoriet (Uppsala universitet) och tester har utförts hos Scania AB Södertälje. Dagens samhälle förbrukar enorma mängder energi. Med hänsyn till både miljöpåverkan och ekonomi är det viktigt att processer är effektiva med höga verkningsgrader. Det finns många sätt att mäta effekt inom industrin, det de har gemensamt är att installationen är avancerad, kräver tid och planering. Endast en behörig elektriker får installera mätanordningen. Projektets syfte är att ta fram en prototyp för effektmätning som enkelt kan anmodas utanför centralen och därmed förenkla ingreppet och förkorta tidsåtgången. Genom att fästa sensorer runt ingående matningskabel kan magnetfältets asymmetriska flödestäthet utnyttjas och inducera spänning proportionell mot den ström som går i ledarna. Resultatet är ett instrument som tillsammans med en dator beräknar ström, fasvinkel och effekt. Vid mätning av strömmens effektivvärde beräknades den maximala skillnaden mellan vår prototyp och Scania Maintenances nuvarande utrustning upp till 29 %. Dock under en längre tid (&gt; 15 min) är skillnaderna av medelvärdet endast 1.2 % och noggrannheten beräknas till 3.67A med 95 % konfidensintervall. Fasvinkelns noggrannhet beräknades till plus 6 och minus 12 %.

The digitalization of our community, robotization of our industry and electrification of our transports leads to an increasing demand of electric power, which relies on a strong and reliable grid. In order to continuously be able to deliver stable and qualitative electric power all over Sweden the grid needs to be expanded. To safely expand the grid, several laws, regulations and safety precautions needs to be followed and one of them applies to the magnetic field from high voltage power lines. This Master thesis aims to show two different ways of calculating the magnetic field from high voltage power lines. The first way is to take the transmission line catenary in account and the other is to approximate a straight line and show the magnetic field extension. It also aims to show how the field looks close to transmission poles, both straight and with angles, in order to find out if that changes the field outcome. Both ways of calculating the field shows the same magnetic field magnitude below the point where the catenary hangs down the most. With the catenary taken into account, the magnetic field strength is lower than with the approximation with straight line, and shows the real field extension from the powerline. Using the straight line approximation, the magnetic field is higher and constant below the whole power line. As both ways of calculating takes a high amount of time, the one that gives the real field extension is recommended to use for real life application.