Essa dissertação desenvolve e faz uso de uma técnica de medição com objetivo de obter dados experimentais envolvidos no ciclo de trabalho dos compressores herméticos alternativos, largamente utilizados nos sistemas de refrigeração. O trabalho mostra o comportamento das válvulas de admissão e descarga durante o funcionamento do compressor, as pressões no cilindro, na sucção, na descarga e também a variação de rotação do eixo durante um ciclo de compressão completo. Todas as características mensuradas estão referenciadas à posição angular do eixo do compressor, o que permitiu monitorar todos os eventos em função do seu deslocamento angular. Para o desenvolvimento desse trabalho foi necessário planejar um sistema de medição robusto, não vulnerável aos fatores ambientais, presentes dentro da carcaça do compressor. A limitação do espaço físico foi um fator de grande importância na escolha dos sensores, assim como a velocidade de resposta dos instrumentos, pois um ciclo de compressão tem período menor que 0,020 segundos. A coleta dos dados e a análise dos sinais foram realizadas com o auxilio de hardware apropriado e software especialmente desenvolvido. / In this dissertation it is developed and applied measurement methods to obtain experimental data of a hermetic compressor work cycle, widely used in the refrigeration systems. This work shows the suction and discharge valve behaviors, the pressure in the cylinder, as well as in the discharge and suction chambers, and also crankshaft rotation variation during a complete compression cycle. All the measurements are reference to crankshaft angular position of compressor which allows to verify the events as a function of the crankshaft angular displacement. For the development of this work it was necessary to plan a reliability measure system, not affected by environmental factors inside the housing of compressor. The inner space limitation was an important feature for choosing the sensors as well as their time response, since the period compression cycle is less than 0.020 seconds. The data acquisition and signal analysis were done with appropriate hardware and it was developed a specific software.

Abstract Brain disorders such as epilepsy, dementia and other mental illnesses induce increasing costs on health care systems with aging populations. The most effective treatment of these disorders would be either prevention or intervention of the disorder before irreversible damage develops. However, despite the increased interest in different brain diseases, many of them are still detected too late. One reason for this is the lack of appropriate functional imaging modality that can critically sample the targeted physiological phenomenon. Furthermore, it has been shown that one imaging modality is not enough to cover brain functionality properly; a multimodal approach is required. The main goal of this thesis was to validate near-infrared spectroscopy (NIRS) for brain measurement and to integrate it into a multimodal neuroimaging setup that can critically sample basic human physiological phenomena. A novel key element was the combined use of NIRS with ultra-fast magnetic resonance encephalography (MREG), electroencephalography (EEG), continuous non-invasive blood pressure and anesthesia monitoring as a synchronous system. This unique multimodal neuroimaging set-up with a new functional magnetic resonance imaging sequence, MREG, can sample human brain physiology at 10 Hz sampling rate without cardiorespiratory aliasing. The implemented setup was successfully used in scanning multiple patient and control populations. With the help of critical sampling rate, non-stationarity between the measured signals reflecting brain pulsations could be detected. Combined NIRS and EEG showed the capability to monitor therapeutic opening of the blood-brain barrier during treatment of central nervous system lymphoma for the first time in humans. Furthermore, our multimodal neuroimaging setup enabled the mapping of the recently described brain avalanches and glymphatic pulsation mechanisms of the brain. In conclusion, the ultra-fast multimodal laboratory with integrated NIRS offers novel and more comprehensive views on basic brain physiology. The measures from this thesis also have the potential to offer new, quantitative biomarkers for the detection of different brain disorders prior to irreversible damage. / Tiivistelmä Aivosairaudet kuten epilepsia, dementia ja muut mielenterveyden häiriöt aiheuttavat kasvavissa määrin kuluja ikääntyvien ihmisten terveydenhuollossa. Näiden tautien tehokkain hoitokeino olisi joko ennaltaehkäisy tai varhainen havaitseminen ennen peruuttamattomien kudosvaurioiden kehittymistä. Lisääntyneestä kiinnostuksesta huolimatta monet aivosairaudet havaitaan edelleen liian myöhään. Osasyy tähän on sopivan toiminnallisen kuvausmenetelmän puuttuminen, jolla voitaisiin kuvata haluttu fysiologinen ilmiö riittävän nopeasti. Onkin osoitettu, ettei yksittäinen kuvausmenetelmä riitä aivojen toiminnan riittävän tarkkaan ymmärtämiseen, vaan siihen tarvitaan eri menetelmien yhdistämistä. Tämän väitöskirjatutkimuksen päätarkoituksena oli arvioida lähi-infrapunaspektroskopian (NIRS) soveltuvuutta aivojen toiminnan mittaamisessa sekä integroida se osaksi multimodaalista neurokuvantamisjärjestelmää. Uutena elementtinä NIRS:iä käytettiin yhdessä ultranopean magneettiresonanssienkefalogrammin (MREG), aivosähkökäyrän (EEG), jatkuva-aikaisen kajoamattoman verenpaineen mittauksen ja anestesiamonitoroinnin kanssa samanaikaisesti, ajallisesti synkronoituna. Yhdessä uuden toiminnallisen magneettikuvaussekvenssin, MREG:n, kanssa tällä ainutlaatuisella multimodaalisella neurokuvantamisjärjestelmällä voidaan kuvata ihmisen aivojen perusfysiologiaa 10 Hz näytteistysnopeudella ilman sydämen sykkeen ja hengityksen laskostumista. Toteutetulla multimodaalisella mittausjärjestelmällä tehtiin useita onnistuneita kuvauksia eri potilasryhmillä ja terveillä koehenkilöillä. Kriittisen näytteistämisen ansiosta voitiin havaita epästationaarisuutta aivojen pulsaatioita heijastelevien signaalien välillä. NIRS:n ja EEG:n samanaikainen mittaaminen mahdollisti ensimmäistä kertaa ihmisen veriaivoesteen aukeamisen monitoroinnin keskushermostolymfoomapotilaiden hoidossa. Lisäksi multimodaalinen neurokuvantamisjärjestelmä mahdollisti hiljattain havaittujen aivojen vyöryjen (engl. avalanches) ja glymfaattisten pulsaatioiden kartoittamisen. Yhteenvetona voidaan todeta, että väitöskirjatyön aikana toteutettu multimodaalinen laboratorio yhdessä NIRS:n kanssa mahdollistaa aivojen perusfysiologian edistyksellisen ja tarkan tutkimisen. Nyt kehitetyt mittarit saattavat myös tarjota uusia, kvantitatiivisia biomarkkereita eri aivosairauksiin ennen vakavien vaurioiden syntymistä.

Examensarbetet har utförts hos RotoSub AB i Linköping. RotoSub fokuserar på innovativa lösningar inom brusreducering för fläktar och är även utvecklingspartner med det österrikiska företaget Noctua, som utvecklar och tillverkar kompaktfläktar och processorkylare inom elektronikbranschen. Under examensarbetet har en flödestestkammare för kompaktfläktar utvecklats och tillverkats. Testkammaren utnyttjar ett högupplöst motstånd som ger möjlighet till ett flertal driftpunkter för att konstruera detaljerade fläktkurvor. Detta låter RotoSub noggrant analysera och undersöka fläktkaraktäristiken under utvecklingsstadiet. I rapporten undersöks två metoder för att bestämma luftflödet genom testkammaren. Däribland en känd geometri i form av munstycken, enligt den amerikanska standarden ANSI/AMCA 210-16 samt utnyttjandet av en varmtrådsanemometer. Vidare undersöks alternativ för att konstruera ett högupplöst motstånd med hög pålitlighet och repeterbarhet, samt en tryckmätningsmetod som tillåter en jämn avläsning av det statiskatrycket som testfläkten ger upphov till. Under utvecklingen tillverkades prototyper där koncept testades och utvärderades, innan slutprodukten kunde modelleras i ett CAD-program för att slutligen tillverkas fysiskt. Slutprodukten tillverkades huvudsakligen i styren-akrylnitril (SAN) samt ett fåtal komponenter i polylaktid (PLA) och aluminium. Testkammaren använder sig av en tryckring med fyra tryckportar, en varmtrådsanemometer för att mäta luftflödet samt en roterande skiva som drivs av en stegmotor för att högupplöst variera motståndet i testkammaren. Testkammaren har visat sig kapabel att konstruera fläktkurvor för samtliga fläktstorlekar undersökta under arbetet med god repeterbarhet. Vidare arbete finns gällande tätning, då ett visst läckage finns i testkammaren vilket ger ett systematiskt fel i fläktkurvorna vid låga flöden där maximalt statiskt tryck inte kan uppnås. / This undergraduate thesis has been carried out at RotoSub AB in Linköping, Sweden. RotoSub develop innovative solutions for noise-reduction in fans. RotoSub are also development partners to the Austrian company Noctua, who design and develop fans and processor coolers for the electronics industry. During the thesis a compact airflow test chamber has been designed and constructed. The test chamber utilises a high-resolution load to measure and create a fan curve. The high-resolution load ensures that a large amount of operating points can be measured, which gives RotoSub the opportunity to closely analyse the characteristics of the fan being tested. In this thesis two different methods of measuring the airflow through the test chamber have been studied. Firstly a method of using nozzles to calculate the flow according to the standard ANSI/AMCA 210-16. Secondly the use of hot-wire anemometry to measure the airflow through the test chamber. Methods of measuring static pressure behind the test fan with high accuracy and stable readings have also been studied. Different high-resolution loads have been studied to ensure high repeatability and reliability. During the development phase, prototypes of the different components were created to allow for testing and evaluation before a final design was chosen. After the designs for each component was decided, the final design was modelled in CAD before being fabricated and constructed. The construction mostly utilises styrene-acrylonitrile (SAN) but with certain components made from polylactic acid (PLA) and aluminium. Pressure readings are taken behind the fan being tested using static ports placed on the outside of a hollow diffuser, mounted on the inlet of the test chamber. The hollow diffuser is filled with foam to stabilise the pressure readings. The chosen method of measuring airflow through the test chamber was hot-wire anemometry for its broad measurement range, high accuracy and simplicity in implementation. The design of the high-resolution load was chosen to be a rotating gate with two ports. As the gate rotates these ports openor close. The rotating gate is driven by a stepper-motor. This design allowed for very fine control at high loads and ensures reliable operation with a minimal amount of moving parts. Tests with the finished test chamber have shown that the test chamber is capable of measuring and creating high-resolution fan curves with high repeatability. However the test chamber cannot measure static pressure at zero flow as there are currently leaks within the test chamber that allows a small amount of flow through the chamber when the variable load is fully closed. This leads to a systematic error when creatingfan curves, mainly at lower flow rates and higher static pressures. Further work with this test chamber is needed to reduce leaks, which would improve measurement precision.

The aim of this thesis is to design an air conditioning system of a flat unit in two variants of piping. The piping system of the first floor is installed into the floor in one variant, in the other it is in the ceiling. Data received from measurements within the experiment have been used for the design. The result of the measurement are minor loss coefficient implemented for bending pipes and pressure losses caused by rubbing. These values are used for dimensioning piping variants. Both types of piping are described in the theoretical part and the method of how the experiment had been processed.

Cílem této diplomové práce bylo provést diagnostiku vysokonapěťového stejnosměrného stykače se zaměřením na zpětnou komutaci a lepení oblouku, navrhnout a ověřit úpravy, které odstraní tyto negativní jevy. Měření obloukového napětí, tlaku a pomocí rychlokamery byly použity při diagnostice těchto jevů. Změny na arcrunnerech a jhu magnetického obvodu byly využity při jejich odstraňování. Úpravy na arcrunneru zmenšily skokové nárusty délky oblouku a úpravy na jhu navýšily sílu na oblouk mezi rozevírajícími se kontakty. Navrhnuté změny na stykači snížily časovou ztrátu v důsledku zpětné komutace, a tak zkrátily čas přenosu oblouku.

The subject of this diploma thesis is the creation of a spark ignition thermodynamics model using pressure data measured on the actual engine. The model made in Matlab programming language combines Wiebe function for fuel energy release and Woschni correlation for heat transfer between in-cylinder gasses and cylinder walls. The created model contains compression and expansion stroke only, that's why are conditions at the start of compression and total heat addition calculated by measured pressure data from Skoda 1.0 MPI engine. Creation of transparent model by Matlab scripts enables other users to understand the basics of „zero-dimensional“ thermodynamics models properly, which are used by number of commercial solvers such as GT-Power simulation software. First part of this thesis deals with fundamental laws of heat addition and heat transfer, description of equations for its modelling and application. The major section is devoted to Matlab model, where defined input parameters are mentioned, description of model operation and model parameters influence study. Next parts develops issues of combustion pressure measurement and creation of engine simulation by GT-Power software used for comparison with Matlab model. In the thesis conclusion are simulations and actual engine data differences discussed.

The thesis deals with formation of a workplace for preparation gaseous mixtures and their future usage. The main goal of the thesis is testing of new materials which have suitable usage as catalysts. Gaseous mixture is prepared by calorimetric mass flow meters with control valve and multiposition microelectric valve actuators. The next part describes measuring of pressure and temperature and controlling of furnace temperature. The thesis deals with specifications of all devices, their circuitry, communication and program controlling. All devices are controlled by computer with program which is programmed in LabVIEW.

The aim of this master‘s thesis is design and construction of home meteo weather station, the choice of applicable temperature, humidity and pressure sensors and characterization of workable device of station. The core of the station is microcontroller ATmega8 used for process data from sensors. Evaluative criteria for choice of sensors will be comunicate interface, accuracy, operating range, current drain and other aspects. Outer transmittin unit measure air temperature and relative humidity. These data are trasmitted by wireless radio module to interior receiving unit, that measure interior temperature and atmospherical pressure and represent measured data to LCD display including dew point. The data are transmitting to the internet and storing in the database. Measured values are available on the web page where you can display the graphs of last measured values.

This thesis treats concept of autonomous temperature, relative humidity and pressure USB datalogger. Also there is explained datalogger function, hardware design with respect on device consumption and design of chassis. Furthermore, there is described communication protocol for control and reading out data by the PC. Furthermore, there are described firmware drivers for some used components and modules for USB communication, RTC and data compression. Lastly there is described software which is used for datalogger configuration and data read out.

Für die Untersuchung von Luft/Wasser-Strömungen wurde ein horizontaler Acrylglas-Kanal mit rechteckigem Querschnitt gebaut. Der Kanal ermöglicht Gleich- und Gegenstrom-Versuche bei Atmosphärendruck, insbesondere die Untersuchung der Schwallströmung. Es wurden optische Messungen mit einer Hochgeschwindigkeits-Kamera durchgeführt, die durch synchronisierte dynamische Druckmessungen ergänzt wurden. Für die Analyse der Bilder wurde eine Methode zur Erfassung der Phasengrenze entwickelt und diese anhand möglicher Anwendungen getestet. Die Druckmessungen zeigten, dass der Druck bei Schwallströmungen um einige Kilopascal ansteigt und wieder abfällt, sobald der Schwall aus dem Kanal austritt. Zudem wurden Geschwindigkeiten in der flüssigen Phase mittels nicht invasiver Verfahren gemessen. Das durchschnittliche Geschwindigkeits-Profil am Kanaleintritt wurde mit Ultraschall-Köpfen bestimmt. Die Ermittlung des Geschwindigkeitsfeldes in einem Schwall erfolgte mit PIV (Particle Image Velocimetry).