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Tjockleksmätning av rör med ultraljud görs typiskt genom att mäta tiden mellan två efterföljande ekon av en utsänd puls. Detta är ofta en svår process som är känslig för störningar och påverkan utifrån. Denna rapport beskriver hur detta i stället kan göras i frekvensdomänen för att minska effekterna av dessa problem. För att göra detta härleds en signalmodell som beskriver de effekter som är nödvändiga för att utföra mätningarna. Utifrån signalmodellen togs metoder fram för att analysera och fastställa tjockleken på den uppmätta signalen. En av metoderna fungerar så bra att den skulle kunna användas. / Ultrasonic thickness gauging of steel tubes is typically performed by observing the time difference between two following echoes. This process is often connected to various problems regarding interference. This thesis describes how to avoid these problems by using signal processing and analyzing the signals in the frequency domain. To achieve these results a signal model that describes the necessary effects is derived. From this model different measurement methods to analyze and determine the thickness are developed. One of the methods proved to be useful.

Today people spend all the more time indoors. Asthma, allergies and Sick Building Syndrome (SBS) are affecting an increasing number of people. The remedy for all these affections has long been to increase the volume flow of outdoor air in the ventilation but at the same time cities all over the world are struggling with air pollution and smog rising above endangering levels. Living filters present a new solution where part of the indoor air can be purified and recirculated in a building. This project has compiled research on the area to describe the how and why concerning air purification by plants. Independent research conclude that plants can reduce most hazardous chemical agents in the air. Climate change, global warming and increasing demands on energy performance induces a race for countries and companies to improve energy efficiency in all sectors. To the building engineering sector living filters presents a unique solution to cut ventilation energy loses. A powerful simulation tool IDA ICE was used to estimate the energy saving capacity when a living filter is applied in the lunch room of an office floor. Another simulation software; Comsol Multiphysics was used to illustrate the aspects of ventilation flow when a living filter cabinet is deployed in a room. The simulation results show that for three living filter cabinets each measuring 0,7x0,8x1,73 cm the buildings energy usage is reduced with more than the living filters use to operate. The single room simulations then show how a living filter can be accommodated with both mixing and displacing ventilation. However, these simulations also illustrate the importance of the living filters placement to achieve maximum ventilation efficiency.  The conclusions from this work are that living filters can reduce building sector energy demands and provide significant indoor environmental benefits. The main issue for using living filters is identified to be building regulations putting strict demands on outdoor air flow and that the hygienic function of each living filter must be verified before it may replace outdoor air.

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Dialys ersätter njurens funktion att rena blodet och att återställa kroppens elektrolytbalans. En viktig del inom dialys är vattenreningen och kvalitén på vattnet. För att avgöra kvalitén så används bakterieodling som metod och nackdelen med detta är det tar en lång tid att få provsvar. Genom att mäta konduktivitet i samband med konceptet A0 så kan antalet provtagningar sänkas och fördelen med detta är att det sparar både tid och pengar. En existerande mjukvara har utvecklats i ett tidigare projekt och syftet med detta examensarbete är att förbättra prestanda och användarvänligheten i den existerande mjukvara och samt utveckla en modul som genererar loggfiler som i ett senare skede kan göras kompatibelt med andra vattenrenare. Det objektorienterade kodspråket C# används som utvecklingsmiljö och arbetet utfördes på Centrum för medicinsk teknik och strålningsfysik – Forsknings- och utvecklingsavdelningen (CMTS-MTFoU) på Norrlandsuniversitetssjukhus. En modul som skapar loggfiler i ett liknande format som Aquaboss loggfilerna utvecklades separat från övervakningsmjukvaran. Implementering i övervakningsmjukvaran skedde genom att modifiera källkoden för grafen så blev den kompatibel med de skapade loggarna. Det resulterade i en fungerande och förbättrad version av övervakningsmjukvaran i både prestanda och användarvänlighet. Mjukvaran är dock fortfarande i teststadiet och måste genomgå ytterligare förbättringar för att kunna med största säkerhet användas i region Västerbotten. Den största förändringen är att en ytterligare graf utvecklades som plottar värdena från de skapade loggarna som ska i ett senare skede ska kunna ersättas eller vidareutvecklas så att värden från andra vattenrenare ska bli kompatibla med grafen. / If a patient has a kidney failure a hemodialysis machine recreates the kidneys function to clean the blood and stabilize the body’s electrolyte balance. One of the important aspects of a dialysis-machine is the water purification process and the water quality. To determine the water quality, two measurements related to disinfection are in consideration, the concept of A0 and conductivity. The purpose of this work is to improve on the existing software that monitors the disinfection effect and the conductivity in various ways that includes performance and user friendliness also, to develop a separate module that generates logfiles with randomized values in reasonable intervals that can be read through a graph and at a later stage improved upon to be used by different water purifiers then from Aquaboss. The overall goal is that the monitor software will be implemented and used throughout the region of Västerbotten. C# with Microsoft Visual Studios 2019 was used during the development process and the work was conducted at CMTS-MT-FoU at Norrland university hospital, Umeå. The priority was creating a logfile generator separate from the monitor software and replicating the real logfiles in a text format. Thereafter implementing this module into the monitor software, itself. The processing of the logfiles with data stretching back to the last two years takes around 10-14 seconds to complete and freezes the user interface (UI). To improve this, all the logic that does the processing was put on a separate thread. A progress bar was added with a constant animation to give a visual indication that and ends when the processing phase is finished. This resulted in an improved version of the existing monitoring software in terms of performance and user friendliness in the graphical interface. The point of the logfile generator is to be replaced in a later stage by values or logfiles from a water purifier of different kinds then what is right now currently used in the developed monitor software (Aquaboss).

Ever since 1968, when the method of flexible bronchoscope was created, the specific method of reusable instruments has been the name of the game. The idea of having the best possible equipment for usage seemed like the most optimal solution for the growing general market that is bronchoscopy. Over the past few years, that narrative has drastically changed, with a rapidly growing market for disposable instruments. Why now and what the benefits are for using disposable over reusable bronchoscopes are common enquiries that are being delved into. This study is aimed to analyse the pros and cons of the different methods, as well as understanding the cost effectiveness. Questions such as, “during a year long period, what method is the cheapest”, “what kind of materials go into a bronchoscope, are their differences” and “what is the most preferred method by relevant personnel” are questions that have been examined. To find these answers, relevant personnel at Swedishhospitals were interviewed, and thorough research was conducted through published articles. The results, pointed towards the fact that it depends on how often the bronchoscope is being used. A smaller hospital that uses a bronchoscope three times a year will benefit from using a disposable bronchoscope from a cost-effective perspective. While a bigger hospital that uses a bronchoscope more than 1000 times a year, will benefit from using a reusable bronchoscope from a cost-effective perspective. If you however take the rate of infections of 2.8% from using a reusable bronchoscope into account, the disposable instrument is the optimal solution. This will work parallel with the potential risk of costs from a fault diagnosis, which increases with the worse camera that the disposable bronchoscope provides. As of today there is no simple answer to which solution is the better one both economically and environmentally. What hospitals should do is make calculations and balance the options against each other and find the best solution for their hospital according to their needs and possibilities.

Användandet av 3D-skrivare har ökat inom sjukvården, och möjliggjort utskrift av anatomiska modeller. Karolinska Universitetssjukhuset i Solna planerar att starta ett 3D-laboratorium, med möjlighet till egen produktion av anatomiska modeller. För detta behövs kunskap kring vilka riktlinjer som ska följas, samt möjlighet till kvalitetssäkring av skrivare. I detta arbete undersöks regelverken kring 3D-printing, och ett kvalitetssäkringsobjekt för framtida kvalitetssäkring tas fram. Regelverket för medicintekniska produkter undersöktes bland dokument från EU, USA, och Australien. Tolkningen av EU:s publikationer görs via kontakt med Läkemedelsverket och Socialstyrelsen. Södertälje Sjukhus, jurister, samt professorer vid Stockholms Universitet och Kungliga Tekniska Högskolan kontaktas också med frågor kring riktlinjer. Resultatet visar på ett vagt och subjektivt tolkat regelverk inom EU, där 3D-printade anatomiska modeller kan tolkas som specialanpassade- eller egentillverkade produkter. Kvalitetssäkringsobjektet tas fram med grund i 13 kriterier. De kriterier som i detta arbete ej visar skillnad mellan utskrivna modeller, däribland negativa vinklar, spiral (form), kantighet och ömtålighet spiral, kan bytas ut eller specificeras på annat sätt. Kriterier som minsta hålbredd, kvalitetssäkringsobjektets bottenarea, släthet, självsprickor, spiral (kvalitet) och sprickor (hål) visade på kvalitetsskillnader hos utskrifterna. / Utveckling av 3D-laboratorium på Karolinska Universitetssjukhuset

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<p>This master's thesis addresses two main problems. The first is how to suppress a common mode voltage that appears for current shunts, and the second how to let a voltage divider work under an unloaded condition to prevent loading errors and thereby a decreased measurement accuracy. Both these problems occurs during calibration of power meters, and verification of current shunts and voltage dividers. To the first problem three alternative solutions are presented; prototype a proposed instrumentation amplifier circuit, evaluate the commercial available instrumentation amplifier Analog Devices AD8130 or let the voltage measuring device suppress the common mode voltage. It is up to the researchers at SP to choose a solution. To address the second problem, a prototype buffer amplifier is built and verified. Measurements of the buffer amplifier show that it performs very well. At 100 kHz, the amplitude error is less than 20 μV/V, the phase error is less than 20 μrad, and the input R_p is over 10 MΩ. This is performance in line with the required to make accurate measurements possible at 100 kHz and over that.</p>

<p>ABB:s MACH2 system uses a number of currents to ignite thyristors for AC/DC-trassfformation and they are measured for control and protection. The measurement methods used today has major drawbacks. Two alternative techniques are investigated, one based on the Hall-Effect (HED) and the other based on Anisotropic Magnetoreistanse (AMR), both techniques sensing the magnetic field produced by currents in a conductor. The HED hawe low sensitivity so some kind of flux concentrators is needed. This adds volume, costs and complexity to the device. The AMR technique is much more sensitive than the HED. Unfortunately AMR are also much more sensitive for high over currents that may damage the devise, and they are not as common on te market. By testing linearity, step response and frequency dependency for some components, my conclusion is that HED components with toroidal flux concentrators utilizing magnetic feedback (Closed Loop, CL) may be used in this particular application. A drawback with CL are that they, when measuring sharp edged step signals, suffer from overshoots at the output that might activate the over current protection.</p>