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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Advanced X-ray Detectors for Industrial and Environmental Applications

Reza, Salim January 2016 (has links)
The new generation of X-ray free electron laser sources arecapable of producing light beams with billion times higherpeak brilliance than that of the best conventional X-ray sources.This advancement motivates the scientific community to pushforward the detector technology to its limit, in order to de-sign photon detectors which can cope with the extreme fluxgenerated by the free electron laser sources. Sophisticated ex-periments like deciphering the atomic details of viruses, filmingchemical reactions or investigating the extreme states of matterrequire detectors with high frame rate, good spatial resolution,high dynamic range and large active sensor area. The PERCI-VAL monolithic active pixel sensor is being developed by aninternational group of scientists in collaboration to meet theaforementioned detector requirements within the energy rangeof 250 eV to 1 keV, with a quantum efficiency above 90%.In this doctoral researchwork, Monte Carlo algorithm basedGeant4 and finite element method based Synopsys SentaurusTCADtoolkits have been used to simulate, respectively, theX-rayenergy deposition and the charge sharing in PERCIVAL. Energydeposition per pixel and charge sharing between adjacent pixelsat different energies have been investigated and presented.Novel methods for industrial and environmental applica-tions of some commercially available X-ray detectors have beendemonstrated. Quality inspection of paperboards by resolv-ing the layer thicknesses and by investigating orientation ofthe cellulose fibres have been performed using spectroscopicand phase-contrast X-ray imaging. It was found that, usingphase-contrast imaging it is possible to set burn-out like qualityindex on paperboards non-destructively. X-ray fluoroscopicmeasurements have been conducted in order to detect Cr inwater. This method can be used to detect Cr and other toxicelements in leachate in landfills and other waste dumping sites. / Acceleratorbaserade röntgenkällor utvecklas ständigt, dessakan producera röntgenstrålning med miljarder gånger så högeffekttäthet som de starkaste konventionella röntgenkällorna.Därför finns en vetenskaplig utmaning att utveckla röntgende-tektorer som inte förstörs i de extrema flöden som genereras avdessa röntgenkällor. De visioner som finns för de nya källornaär t.ex.; att avbilda detaljer av virus ner på atomnivå, att filmakemiska reaktioner eller att undersöka extrema tillstånd hos ma-teria. Dessa typer av experiment kräver röntgendetektorer medhög bildhastighet, hög spatial upplösning och stort intensitets-omfång och stor aktiv sensoryta. Detektorsystemet PERCIVALsom bygger på aktiva pixlar med energiupplösning utvecklasinom ett internationellt vetenskapligt samarbetsprojekt. Må-let är att uppfylla detektorspecifikationerna för de nämndaexperimenten inom energiområdet 250 eV till 1 keV, med enkvantverkningsgrad över 90 %.I föreliggande vetenskapliga avhandlingsarbete har simule-ringar av energideponering i PERCIVAL-detektorn genomförtsbaserat på Monte Carlo-algoritmer och simuleringar av ladd-ningsdelning mellan pixlar har simulerats med hjälp av finitaelementmetoden. Därmed har energideponeringen per pixeloch laddningsdelningen mellan närliggande pixlar vid olikaenergier kunnat utredas och presenteras.I avhandlingen demonstreras nya lovande metoder för in-dustriella applikationer och miljöövervakning,därkommersiellttillgängliga röntgendetektorer kan användas. Kvalitetsövervak-ning av kartongtillverkning genom att mäta bestrykningstjock-lek och fiberorientering kan realiseras med energiupplöstaröntgenbilder eller faskontrastbilder i röntgenområdet. Det kankonstateras att med icke-förstörande provning, genom faskon-trastbilder, kan kvalitetsindexvärlden erhållas på samma sättsom kvalitetsindex kan erhållas från ”burn-out”-mätningar.Spektroskopiska mätningar av röntgenflourescens har genom-förts för att detektera krom (Cr) i vatten. Metodik för att detek-tera krom och andra giftiga metaller i lakvatten från deponioch annan lagring för giftigt avfall har utarbetats.
412

Evaluation of 3D MRI Image Registration Methods

Ivarsson, Magnus January 2017 (has links)
Image registration is the process of geometrically deforming a template image into a reference image. This technique is important and widely used within thefield of medical IT. The purpose could be to detect image variations, pathologicaldevelopment or in the company AMRA’s case, to quantify fat tissue in variousparts of the human body.From an MRI (Magnetic Resonance Imaging) scan, a water and fat tissue image isobtained. Currently, AMRA is using the Morphon algorithm to register and segment the water image in order to quantify fat and muscle tissue. During the firstpart of this master thesis, two alternative registration methods were evaluated.The first algorithm was Free Form Deformation which is a non-linear parametricbased method. The second algorithm was a non-parametric optical flow basedmethod known as the Demon algorithm. During the second part of the thesis,the Demon algorithm was used to evaluate the effect of using the fat images forregistrations.
413

Solar Cell Powered Boat

Hammarlund, Tomas, Sundin, Jesper, Kövamees, Johan January 2017 (has links)
The objective of this project is to find out experimentally and through theoretical calculations and applications whether a cargo ship can be operated by means of solar cells. The project deals with the amount of research and applications already available in this area today and which areas could be developed and improved in future research. A radio-controlled miniature ship was purchased and modified to conduct tests on with solar cells. The data collected from these tests and the researched data were then analyzed to make calculations on real sized ships. A system was designed together with the miniature ship motors, the solar cells and an Arduino to carry out these tests. The miniature ship’s solar cells contributed with about 30% of the total power. The two theoretical ships had a lower percentage of about 4% and 8% respectively at maximum throttle. An economical calculations where both a hybrid cargo ship and an fully electrical ship concluded that it’s expensive but there is a profit in build each over the course of 20 years.
414

Den samhällsekonomiska nyttan av förkortade avbrottstider i 40 kV distributionsnät / The socioeconomic benefit of reduced interruption times in the 40 kV distribution grid

Svensson, Wictor, Haydari, Farzad January 2018 (has links)
Examensarbetet har genomförts på uppdrag åt Vattenfall Eldistribution AB nedan kallat Vattenfall. När Vattenfall idag bygger nya 40/10 kV stationer installeras normalt brytare i ledningsfacken i stället för frånskiljare. Dessa bestyckas dock inte med reläskydd utan används enbart som kopplingsorgan vid driftomläggningar. Arbetet är en teknisk ekonomisk jämförelse över den samhällsekonomiska nyttan av att installera reläskydd i de nya 40 kV ledningsfacken. Genom dessa installationer förkortas avbrottstiderna i 40 kV distributionsnäten då en mer selektiv bortkoppling kan ske av felbehäftad del. I arbetet har även ingått att undersöka nyttan av att driva 40 kV näten maskade i stället för som idag radiellt. Den ekonomiska värderingen som sträcker sig över 30 år baseras på tre delar; a) samhällsekonomiska avbrottskostnader och hur de påverkas vid de olika driftsätten, b) nätförlusternas förändring vid radiell eller maskad drift och dess resulterande förlustkostnader samt c) skyddsutrustningskostnader. Analysen baseras på tre typfall; fall 1: befintligt radiellt drivet nät, fall 2: radiellt drivet nät + utökad skyddsutrustning och fall 3: maskning av nät + mer avancerade skydd. Beräkningarna av avbrottskostnader, skyddsutrustningskostnader och kostnader för nätförluster har genomförts i Excel, lastflödesberäkningar över nätförluster i PSS/E och figurer har ritats i AutoCad. Resultatet visar att den ekonomiska nyttan alltid förbättras i fall 2. Det lönar sig således att investera i utökad skyddsutrustning eftersom den ekonomiska värderingen av avbrottskostnader ger en ekonomisk vinning. Maskningen av näten resulterar alltid i en minskning av avbrottskostnaderna medan nätförlusterna kan både öka och minska beroende på nätets utformning och förhållanden i överliggande nät. Någon generell slutsats går därför inte att dra utan det bör undersökas från fall till fall. / The bachelor’s thesis has been performed for Vattenfall Eldistribution AB, below called Vattenfall. When Vattenfall is building new 40/10 kV stations they normally install circuit-breakers instead of disconnectors in the new 40 kV cable bays. However they aren’t armed with protection, so they’re only used as a coupling tool for switching operations. The work is a technic economic comparison of the socioeconomic benefits of installing protection in the new 40 kV cable bays. The interruption times will be reduced with this installation in the 40 kV distribution grids because of the more selective fault clearance of the malfunction part. The work has also involved an investigation of the benefits of powering the grids meshed instead of radial. The socioeconomic analysis is ranging over 30 years and it’s based on three parts; a) society-based interruption time costs and how it is effected by the different cases, b) the economic difference for power losses between the meshed grid and the radial grid and c) costs for protection equipment. The analysis is based on three cases, case 1: existing radial grid, case 2: radial grid + extended protection equipment and case 3: meshed grid + more advanced protection equipment. The economic calculations for interruption-times, power losses and protection equipment have been performed in Excel, load flow calculations of power losses in the program PSS/E and figures has been drawn in AutoCad. The result has shown that the financial benefit always improves in case 2, i.e. it's profitable to extend the protection equipment because of the economic value of improved costs of interruption time. The meshed system always results in a reduction of the interruption-time cost but the power losses can either decrease or increase and it depends on the configuration and the circumstances in the supplying network. Therefore, it’s not possible to make a general statement on the meshed examples. Different grids need to be investigated separately
415

Larmanalys för Vattenfall Vattenkrafts produktionsanläggningar längs Göta Älv / Incident analysis of Vattenfall Vattenkraft hydro power facilities in the Göta river

Augustsson,, Jimmy, Printz, Kristoffer, Svensson, Erik January 2018 (has links)
Vattenfall Vattenkraft AB äger 57 storskaliga vattenkraftanläggningar där den installerade effekten överstiger 10 MW. Detta arbete berör larm och dess hantering i de fyra anläggningarna längs Göta älv. Rapporten analyserar larm och utryckningar från åren 2014– 2017 samt även själva larm- och kontrollsystemen, i syfte att identifiera möjliga förbättringsområden. Larmen sorteras efter feltyp, åtgärd, anläggning och säsong. De flesta larmen utgår från turbin och generatoranläggningar och handlar om onormala nivåer eller temperaturer. Sommar- och vintertid orsakar flest larm beroende på älvens varierande vattentemperatur och flöde. De fyra anläggningarna har ungefär samma antal utryckningar vilket är intressant då de varierar stort i ålder. Analysen identifierar inga återkommande fel som inte redan är kända av företaget men författarna rekommenderar att en utredning görs om installation av ålfilter till Lilla Edets kylvattenpumpar. Larmen genereras i anläggningarna och skickas till driftcentralen i Bispgården utanför Sundsvall där operatören ringer upp vakthavande maskinist. Denne måste sedan åka till anläggningen för att på stationsdatorn få detaljerad information om larmets orsak. Rapporten undersöker möjligheten att ge vakthavande tillgång till information från stationsdatorn via VPN, vilket är möjligt att implementera men skulle kräva en noggrann genomgång av vad en sådan funktionalitet skulle innebära för säkerheten. Vidare har larmens beskaffenhet undersökts, dessa är om- och utbyggda efter hand och det saknas en bra överblick. Författarna rekommenderar här en genomgång av larmlistorna och larmens prioritet. Slutligen föreslås en mer kvalitativ inriktning på framtida studier av larmhanteringen. / Vattenfall Vattenkraft AB owns 57 large scale hydro power plants in Sweden with installed power exceeding 10 MW. The study relates to four of the plants located along Göta river. This report analyzes incidents and the related remedial actions that have occurred during the period 2014 – 2017 as well as the alarm and control systems with the aim to identify potential improvements. The incidents are categorized by error, what actions have been undertaken to correct the issue, plant and season. The incidents have predominately originated in the turbine and generator facilities and have been caused by abnormal levels or temperatures. During summer and winter time, this is mainly due to variation in temperature and flow in the river. The four plants have caused a similar amount of alarms, which is interesting as there is a large variation in age. The analysis does not identify any reoccurring issues which were previously unknown to the company, but the authors recommends that an investigation is conducted to assess if eel screens should be installed for the cooling pumps of Lilla Edet. The alarms are generated in the plants and are sent to the control facility in Bispgården near Sundsvall, where the operator calls the local engineer on duty in Trollhättan. The engineer subsequently goes to the plant to access detailed information on the incidents from the local computers. This report examines the possibility to provide the engineer on duty with detailed information from the plant computer via VPN. This would be possible to implement but would require a detailed assessment of the security implications. The status of the alarm system have also been assessed as it have been modified and extended retroactively, and there is currently no comprehensive overview. The conclusion is that a review of the list of incident codes and their priority is recommended.
416

System Model of an Ultra-LowPower Fluorescence Detection Micro-Device

Xue, Yuanyuan January 2020 (has links)
This thesis aims to explore the power consumption limits of Complementary Metal-Oxide-Semiconductor (CMOS) fluorescent biosensors that meet the demand, a Matlab-based calculator is designed, in which users can input required system parameters (such as LED power and noise) to observe the minimum power consumption of each basic component and the constraints of the transimpedance amplifier: cut-off frequency, signal- to-noise ratio, dynamic range, etc. Thereby to provide a reference range for the next level designs of each component in the detection system. In our top-level model, only essential components are included which are: Light-emitting diode (LED) driver, photodiode, transimpedance amplifier (TIA) and analog-to-digital converter (ADC). According to the established model, we have obtained somepractical data: when the LED radiates 1.5 mW of light power and excites 50% offluorescence, three 2 mm􏰀 x 2 mm sized photodiodes are used, and the system cut-off frequency is at 10 KHz, the input noise current is around 1.29 pA√Hz, the signal-to-noise ratio (SNR) is up to 78 dB, the ADC resolution is 13 bits, the power consumption of the transimpedance amplifier can be at lowest of 30 nW, and the ADC power consumption is 87 nW.
417

Connections Provisioning Strategies for dynamic WDM networks

Muhammad, Ajmal January 2012 (has links)
The size, complexity, and the amount of traffic generation of optical communication networks have dramatically increased over the last decades. Exciting technologies, namely, optical amplifiers, wavelength division multiplexing (WDM) and optical filters have been included in optical networks, in order to fulfill end users appetite for bandwidth. However, the users high bandwidth demand will further increase with time, as emerging on-demand bandwidth intensive applications are starting to dominate the networks. Applications such as interactive video, ultra-high definition TV, backup storage, grid computing, e-science, e-health to mention a few, are becoming increasingly attractive and important for the community. Given the high bandwidth requirements and strict service level specifications (SLSs) of such applications, WDM networks equipped with agile devices, such as reconfigurable optical add-drop multiplexers and tunable transceivers integrated with G-MPLS/ASON control-plane technology are advocated as a natural choice for their implementation. SLSs are metrics of a service level agreement (SLA), which is a contract between a customer and network operator. Apart from other candidate parameters, the set-up delay tolerance and connection holding-time have been defined as metrics of SLA. This work addresses the network connections provisioning problem for the above mentioned demanding applications, by exploiting the time dimension of connections request. The problem is investigated for dynamic networks comprising ideal and nonideal components in their physical layer, and for applications with differentiated set-up delay tolerance and quality of signal requirements. Various strategies for different scenarios are proposed, each strategy combining in a different way the concept of both set-up delay tolerance and connection holding-time awareness. The objectives of all these strategies are to enhance the network connections provisioning capability and to fulfill customers demand, by utilizing the network resources efficiently.
418

Elkvalitet och övertoner inom elektronikindustrin

Landin, Josef January 2020 (has links)
No description available.
419

Investigation of Materials and Methods for Integration of Electronics and Intelligent Glass / Undersökning av material och metoder för integration av elektronik och intelligent glas

Nygren, Jonathan January 2020 (has links)
No description available.
420

Battery Sizing and Placement in the Low Voltage Grid including Photovoltaics

Klasson, Alexander, Melin, Philip January 2020 (has links)
Installations of photovoltaic power production increases each year. This can have a negative consequence on the distribution grid where the voltage can increase. The electric distribution companies in Sweden have a responsibility in keeping the grid at certain voltages, and have to reinforce the grid if these voltages are outside these levels. This Master's Thesis investigates the difference in strengthening the grid with help of cables or with help of batteries, especially the economic differences between the two and in which cases they might be viable, both today and in the future. A real case in a low distribution grid, where photovoltaic production was too large will be used as basis of the thesis. In this case, the problematic part of the grid with most production was moved to a network station close by which lead to a significant drop in voltages on the first grid. To evaluate the different solutions a simulation tool developed previously is further built upon, to be able to create simulations of the grid investigated. It is also possible to test replacing or strengthening cables with this tool. An optimisation tool is then created, that is used to test where batteries can be placed and how large they have to be to keep the voltages and currents within set ranges. From the results, the most significant conclusion is that batteries are not yet viable as a replacement for grid reinforcements in the base case evaluated. Today this is mostly due to the steep prices of batteries, and long life-lengths of cables where they can be used for significantly longer than batteries as grid reinforcements. However, in the future, there are situations where batteries may be economically more viable. There is also a portability aspect in batteries, where batteries could be used as a temporary solution where it may not be possible to install cable reinforcements immediately. Lastly, the optimal placement of batteries was established to be as close to the problem zone, i.e. the photovoltaic power production as possible. This means that with growing popularity of stationary batteries at home and electric vehicles, these types of solutions could possibly be used in the future.

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