The aim of this project is detection of gass leak based on the ultrasound sensing. Work introduces ultrasound, mechanism of its propagation and attenuation. From all of the available microphones, the piezoelectric microphone was chosen. Project continues with description of the device, which can be capable of detection of the ultrasound leakage in dangerous, explosive environment. This type of device must meet requirements of SIL 2 standard and ATEX directive for zone 2. Project discusses LNA (Low Noise Amplifier), filters and detection circuits design. The device is modular what means that each module can be freely replaced. The role of these modules is to convert analog signal to digital form suitable for microcontroller HERCULES TSM57012.

Indiana University-Purdue University Indianapolis (IUPUI) / Compressed air is a powerful source of stored energy and is used in a variety of applications varying from painting to pressing, making it a versatile tool for manufacturers. Due to the high cost and energy consumption associated with producing compressed air and it’s use within industrial manufacturing, it is often referred to as a fourth utility behind electricity, natural gas, and water. This is the reason why air compressors and associated equipment are often the focus for improvements in the eyes of manufacturing plant managers. As compressed air can be used in multiple ways, the methods used to extract and transfer the energy from this source vary as well. Compressed air can flow through different types of piping, such as aluminum, Polyvinyl Chloride (PVC), rubber, etc. with varying hydraulic diameters, and through different fittings such as 90-degree elbows, T-junctions, valves, etc. which can cause one of the major concerns related to managing the energy consumption of an air compressor, and that is the waste of air through leaks. Air leaks make up a considerable portion of the energy that is wasted in a compressed air system, as they cause a multitude of problems that the compressor will have to make up for to maintain the steady operation of the pneumatic devices on the manufacturing floor that rely on compressed air for their application. When air leaks are formed within the compressed air piping network, they act as continuous consumers and cause not only the siphoning off of said compressed air, put also reduce the pressure that is needed within the pipes. The air compressors will have to work harder to compensate for the losses in the pressure and the amount of air itself, causing an overconsumption of energy and power. Overworking the air compressor also causes the internal equipment to be stretched beyond its capabilities, especially if they are already running at full loads, reducing their total lifespans considerably. In addition, if there are multiple leaks close to the pneumatic devices on the manufacturing floor, the immediate loss in pressure and air can cause the devices to operate inefficiently and thus cause a reduction in production. This will all cumulatively impact the manufacturer considerably when it comes to energy consumption and profits. There are multiple methods of air leak detection and accounting that currently exist so as to understand their impact on the compressed air systems. The methods are usually conducted when the air compressors are running but during the time when there is no, or minimal, active consumption of the air by the pneumatic devices on the manufacturing floor. This time period is usually called non-production hours and generally occur during breaks or between employee shift changes. This time is specifically chosen so that the only air consumption within the piping is that of the leaks and thus, the majority of the energy and power consumed during this time is noted to be used to feed the air leaks. The collected data is then used to extrapolate and calculate the energy and power consumed by these leaks for the rest of the year. There are, however, a few problems that arise when using such a method to understand the effects of the leaks in the system throughout the year. One of the issues is that it is assumed that the air and pressure lost through the found leaks are constant even during the production hours i.e. the hours that there is active air consumption by the pneumatic devices on the floor, which may not be the case due to the increased air flow rates and varying pressure within the line which can cause an increase in the amount of air lost through the same orifices that was initially detected. Another challenge that arises with using only the data collected during a single non-production time period is that there may be additional air leaks that may be created later on, and the energy and power lost due to the newer air leaks would remain unaccounted for. As the initial estimates will not include the additional losses, the effects of the air leaks may be underestimated by the plant managers. To combat said issues, a continuous method of air leak analyses will be required so as to monitor the air compressors’ efficiency in relation to the air leaks in real time. By studying a model that includes both the production, and non-production hours when accounting for the leaks, it was observed that there was a 50.33% increase in the energy losses, and a 82.90% increase in the demand losses that were estimated when the effects of the air leaks were observed continuously and in real time. A real time monitoring system can provide an in-depth understanding of the compressed air system and its efficiency. Managing leaks within a compressed air system can be challenging especially when the amount of energy wasted through these leaks are unaccounted for. The main goal of this research was to find a nonintrusive way to calculate the amount of air as well as energy lost due to these leaks using time series pressure measurements. Previous studies have shown a strong relationship between the pressure difference, and the use of air within pneumatic lines, this correlation along with other factors has been exploited in this research to find a novel and viable method of leak accounting to develop a Continuous Air Leak Monitoring (CALM) system.

Background: One part of manufacturing a Plate Heat Exchanger (PHE) is to leak test them before delivery. Today, helium is used extensively in leak testing. How-ever, it is unsustainable to use helium in leak testing, because of its non-renewability and therefore becoming more and more expensive. Also, this technology is relatively complex. At the same, PHEs are rising in demand due to lack of energy resources in Europe. Therefore, possibilities emerged for using air based leak testing technologies in upcoming test lines and that is why an evaluation needs to be done to find the most suitable technology. Objectives: The objective of this master’s thesis is to evaluate and identify the most suitable leak testing technology for validating the watertightness requirement of 10−3 mbar·l/s at 1 bar pressure difference. There is a scientific gap in comparing how different air based leak testing technologies perform with different volumes of the test vessels. This thesis will identify the most suitable air based leak testing technology by evaluating three technologies: Pressure Decay, Differential Pressure Decay and Vacuum Decay. With the main focus on how different volumes impacts the performance of each technology. Lastly, this study aims to determine an optimal test pressure that achieves the shortest cycle time for the selected test technology. Choosing the most suitable test technologies will result in fewer production break-downs and interruptions. Additional, being able to phase out helium in leak testing. Methods: The workflow for evaluating the different leak testing technologies began with the implementation and installation of each test setup and ensuring the reliability of the gathered data. After verifying the absence of leakage in the system, a simulated leak was calibrated to match the requirement’s leak rate. Four test vessels with original volumes of 0.10, 0.45, 1.66 and 2.50 l were utilized. Various tests were then performed to answer the research questions, including measurements of leak rate at different pressures, analysis of outgassing characteristics, and determination of cycle time. Finally, by utilizing concept scoring, the most suitable leak testing technology was identified with respect to the volume. Results: The exhibited results in this thesis manifest how the different leak testing technologies perform depending on the volume. The relationship between leak rates and overpressures was obtained, which was then utilized to derive the theoretical detection time. The cycle time and accuracy were determined across various volumes. According to concept scoring, Pressure Decay was deemed the most suitable leak testing technology in terms of six different criteria.   Conclusions: All three technologies were able to determine a leak rate corresponding to the watertightness requirement. From the evaluation, Pressure Decay was the most suitable technology to use across the majority of the volumes, with an accuracy below 15%. The test cycle times were optimizable by selecting an optimum testing pressure.  Therefore, being able to replace the helium leak testing in future test lines. / Bakgrund: En del i processen av att producera värmeväxlare är att de ska genomgå en täthetskontroll innan de levereras till kunden. I dagsläget används helium till största del för att göra täthetskontroller. Däremot är det inte hållbart att bruka helium för täthetskontroller, då det inte är förnyelsebart. Därför blir allt dyrare samtidigt som teknologin som används är komplex. Samtidigt har efterfrågan på värmeväxlare ökat markant till följd av brist på energiresurser i Europa. Som ett resultat av detta uppkom möjligheten att använda luftbaserade tätkontrolls teknologier i framtida testbanor och därför behövs en utvärdering göras av vilken metod som är lämpligast att använda. Syfte: Syftet med arbetet var att utvärdera och identifiera den mest lämpliga test-teknologin för att validera att vattentätskravet uppfylls. Det finns idag ett vetenskapligt gap på hur olika luftbaserade testteknologier presterar beroende på vilken volym som testas. Denna studie identifierade den mest lämpliga luftbaserade tätkontorllstekniken genom att utvärdera följande tre tekniker: Pressure Decay, Differential Pressure Decay och Vacuum Decay. Huvudfocus var på hur olika volymer påverkar tätkontrollens prestanda. Slutligen bestämms det optimala testtrycket som ger den lägsta cykeltiden för den valda testteknologin. Att välja den mest lämpliga test-tekniken kommer resultera i färre haverier och avbrott i produktionslinjen, samt ge möjligheten att byta ut helium som spårgas för täthetskontollerna. Metod: Arbetsflödet för att utvärdera de olika teknologierna för täthetskontroller började med att implementera och installera varje testuppställning och säkerställa att datan var trovärdig. Efter att ha verifierat att inga läckor fanns i systemen,kalibrerades en simulerad läcka för att matcha vattentätskravet läckhastighet. Fyra testobjekt användes med volymerna, 0.10, 0.45, 1.66 och 2.50 l. Olika tester ut-fördes sedan för att svara på forskningsfrågorna, samt gjordes en mätning av läck-hastigheten vid olika övertryck, analys av utgasningskarakteristiken och cykeltiden bestämdes. Slutligen, genom att använda concept scoring identifierades den mest lämpliga teknologin för täthetskontroller beroende på vilken volym som testas. Resultat: Resultatet i detta examensarbete visar hur olika testteknologier presterar beroende på volym. Relationen mellan läckhastighet och övertryck bestämdes och an-vändes för att härleda den teoretiska detektionstiden. Cykeltiden och noggrannheten bestämdes för olika volymer. Utifrån concept scoring var Pressure Decay den mest lämpliga testteknologin utifrån sex olika kriterier.   Slutsatser: Alla tre testteknologierna kunde hitta en läcka motsvarande vattentätskravet. Utifrån utvärderingen var Pressure Decay den mest lämpliga testteknologin för majoriteten av volymerna med en noggrannhet under 15%. Cykeltiden var optimerbar genom att välja det optimala testtrycket. Därför kan Pressure Decay användas som en ersättare för helium vid tätkontroller i framtida testbanor.

手術後の呼吸器からの空気漏出（エアリーク）と腹部及び胸部癒着はそれぞれ、未だに臨床にて大きな課題である。本研究では、安全性に優れた植物性多糖類のアルギン酸ナトリウムに着目し、ゲルやスポンジの材形に加工した。これをPGA不織布と併用して新規エアリーク防止材を開発した。この新規材料は、エアリーク防止だけでなく癒着防止に対しても優れた効果を発揮した。将来的に、この新規材料は、従来材料よりも優れた医療材料として臨床応用されることが期待できると考えられる。 / Sodium alginate is polysaccharide extracted from seaweed and used as a biomaterial clinically. The alginate in this study was used as gel- or sponge-formed and combined with a polyglycolic acid (PGA) mesh, a useful biomaterial clinically; namely this combination was the new sealing material. The purpose of this study was to prevent pulmonary air leak without inducing adhesion. This study was composed of the four animal experiments; the first half of them was about preventing air leak and the latter was about preventing adhesion. All experiments showed that new sealing material was superior to the conventional treatments. Therefore the new sealing material was expected to be applied clinically to a sealing material, which also has an anti-adhesive effect. / 博士(理学) / Doctor of Philosophy in Science / 同志社大学 / Doshisha University

Background: The main focus of the dissertation is the use of nanofibrous biodegradable materials for the healing support of intestinal anastomoses in colorectal surgery. The altered healing process of intestinal anastomosis leads to several types of local complications. Anastomotic leakage is one of the most feared ones. Severe anastomotic leakage causes peritonitis, sepsis and is a life-threatening condition. Reoperation is necessary in many cases, bringing the need for intensive care, and hospital stays prolongation. Extensive peritoneal adhesions are another source of postoperative complications. These adhesions are a frequent cause of bowel obstruction and abdominal discomfort and are the most common reason for readmission after colorectal procedures. Nanofibrous biodegradable materials showed positive effects on the healing process in various locations. We aimed to develop and perfect a biodegradable patch for both prevention of anastomotic leakage and the formation of extensive peritoneal adhesions. Methods: We conducted 3 subsequential experiments on porcine models. In Experiment A, we managed to develop polycaprolactone and polylactic acid- polycaprolactone copolymer nanofibrous patches and applied them on anastomoses on the small porcine intestine. The animals were observed for 3 weeks....

The work was conducted at Saab Dynamics AB in Karlskoga, and the focus was to investigate and evaluate available methods for leak detection of small mechanical components, such as Electro-Explosive Devices (EEDs) and fuzes in warheads and using these methods to investigate whether they work for this purpose. At the start of the project, the problem was that these mechanical components were exposed to contamination, such as moisture and dust but also TNT exudate, plasticizers, gunpowder residues, etc. These contaminants may leak in or out of these components and may result inreduced performance and difficulties for the components to fulfill their function. The work was divided into two phases, with the first phase consisting of finding the best leak detection method available for the company that best suited the circumstances. The second phase of the work was to use the leak detection method evaluated in the first phase and to investigate its eligibility on the company's products and thereafter produce statistical data regarding the various products. The overall purpose of the project is to investigate and evaluate leak detection methods suitable to the company’s products, which may be used to ensure their quality.In phase one where leak detection methods were sought, it was discovered that different leak detection methods are suitable for different sizes of leaks. The search for a method was divided into two categories. A method for major leaks, gross leaks, as well as a method for smaller leaks, fine leaks. To assess which method was best suited for this purpose, standardized methods for product development, such as a decision matrix and a criteria matrix were used to objectively assess and screen appropriate solutions to the problem. The result of this study was that helium leak detection was the best method to analyze minor leaks and the bubble method was the best method for searching for gross leaks. Testing of these methods was done and the methods tested were helium leak detection and bubble test. The components tested were EEDs (<< 1 cc) and fuze holders (>1 cc). All types except one of the fuze holders met the leakage requirements that applied. The tightest component was specifically designed to be completely sealed. This has also been proven from four recuring aging tests conducted by the company. The second most sealed component could only complete one of the aging tests. The value that the completely sealed component got was then used as a recommended limit for leakage. The EEDs upheld a high level of tightness. One of the EEDs was designed to be tight, however the remaining types of EEDs met the same level of tightness. One possible reason for this result is that the internal volume of these detonators is too small to give a realistic and reliable results from these selected method. Because of this, more research should be carried out to find more suitable methods to measure small devices in the expected leakage interval. / Arbetet utfördes på Saab Dynamics AB i Karlskoga, där huvudfokus låg på att undersöka tillgängliga metoder för att läckagesöka små mekaniska komponenter, såsom elsprängkapslar och tändrör i stridsdelar och använda dessa metoder för att undersöka hur väl de fungerar på små mekaniska komponenter. Vid projektets påbörjan var problemet att dessa mekaniska komponenter blev utsatta för kontaminering, såsom fukt och damm men också TNT-exudat, mjukgörande, krutrester etc. Dessa kontamineringar tränger sedan in eller ut ur dessa komponenter och kommer att leda till sämre prestanda och svårigheter för komponenterna att uppfylla sin funktion. Arbetet delades upp i två faser, där den första fasen gick ut på att hitta den bästa läckagesökningsmetoden som fanns tillgänglig för företaget och som bäst passade de omständigheter som rådde. Den andra fasen i arbetet var att använda den läckagesökningsmetod som togs fram i första fasen för att undersöka dess lämplighet på företagets produkter samt ta fram statistiska data gällande läckage. Det övergripande syftet med arbetet är att undersöka lämpliga metoder för läckagesökning som kan appliceras på företagets produkter, med syfte att säkerställa kvalitén på dessa. I fas ett, där läckagesökningsmetod eftersöktes upptäcktes det att olika läckagesökningsmetoder lämpar sig till olika storlekar på läckage. Det beslutades att sökningen efter metod skulle delas upp. En metod för grövre läckage (gross leak) togs fram, samt en metod för mindre läckage (fine leak). För att bedöma vilken läckagesökningsmetod som var bäst lämpad för de olika komponenterna användes strukturerade metoder (kriterieviktsmatris och relativ beslutsmatris) för produktutveckling för att objektivt kunna bedöma och gallra lämpliga läckagesökningsmetoder att gå vidare med. Resultatet av detta var att heliumläckagesökning var den bästa metoden för att söka efter mindre läckor och bubbelmetoden var den bästa metoden för att söka efter större läckor. Testning av dessa metoder gjordes och de metoder som testades var heliumläckagesökning och bubbeltest. De komponenter som testades var små elsprängkapslar (<<1 cc) och större tändrör (>1 cc). Två olika prov gav olika nivåer på tätheten på fyra olika typer av tändrörsobjekt. Den tätaste är designad för att vara tillräckligt tät, vilket visats vid fyra olika åldringsprov. Den näst tätaste klarade bara 1 av 2 åldringsprov. Det värde som den täta komponenten fick användes som ett gränsvärde för att bedöma om tändrör är tillräckligt täta. Elsprängkapslarna uppfyllde en hög nivå på täthet. En av elsprängkapslarna är designad för att vara tät, vilket den var, men resterande typer uppfyllde samma nivå av täthet som den gjorde. En möjlig anledning till detta resultat är att den interna volymen i dessa elsprängkapslar är för liten för att kunna ge ett realistiskt och pålitligt resultat med de provade täthetsmätningsmetoderna. Därför bör det undersökas i vidare arbete om mer lämpliga täthetsmätningsmetoder kan hittas för dessa små komponenter i det förväntade läckageintervallet.

No description available.

The overall aim of the present thesis is to clarify the control of intracellular chloride homeostasis in central neurons, because of the critical role of chloride ions (Cl–) for neuronal function. Normal function of the central nervous system (CNS) depends on a delicate balance between neuronal excitation and inhibition. Inhibition is, in the adult brain, most often mediated by the neurotransmitter γ-aminobutyric acid (GABA). GABA may, however, in some cases cause excitation. GABA acts by activating GABA type A receptors (GABAARs), which are ion channels largely permeable to Cl–. The effect of GABAAR-mediated neuronal signaling - inhibitory or excitatory - is therefore mainly determined by the Cl– gradient across the membrane. This gradient varies with neuronal activity and may be altered in pathological conditions. Thus, understanding Cl– regulation is important to comprehend neuronal function. This thesis is an attempt to clarify several unknown aspects of neuronal Cl– regulation. For such clarification, a sufficiently sensitive method for measuring the intracellular Cl– concentration, [Cl–]i, is necessary. In the first study of this thesis, we examined two electrophysiological methods commonly used to estimate [Cl–]i. Both methods, here called the interpolation and the voltage-ramp method, depend on an estimate of the Cl– equilibrium potential from the current-voltage relation of GABA- or glycine-evoked Cl– currents. Both methods also provide an estimate of the membrane Cl– conductance, gCl. With a combination of computational and electrophysiological techniques, we showed that the most common (interpolation) method failed to detect changes in [Cl–]i and gCl during prolonged GABA application, whereas the voltage-ramp method accurately detected such changes. Our analysis also provided an explanation as to why the two methods differ. In a second study, we clarified the role of the extracellular matrix (ECM) for the distribution of Cl– across the cell membrane of neurons from rat brain. It was recently proposed that immobile charges located within the ECM, rather than as previously thought cation-chloride transporter proteins, determine the low [Cl–]i which is critical to GABAAR-mediated inhibition. By using electrophysiological techniques to measure [Cl–]i, we showed that digestion of the ECM decreases the expression and function of the neuron-specific K+ Cl– cotransporter 2 (KCC2), which normally extrudes Cl- from the neuron, thus causing an increase in resting [Cl–]i. As a result of ECM degradation, the action of GABA may be transformed from inhibitory to excitatory. In a third study, we developed a method for quantifying the largely unknown resting Cl– (leak) conductance, gCl, and examined the role of gCl for the neuronal Cl– homeostasis. In isolated preoptic neurons from rat, resting gCl was about 6 % of total resting conductance, to a major part due to spontaneously open GABAARs and played an important role for recovery after a high Cl– load. We also showed that spontaneous, impulse-independent GABA release can significantly enhance recovery when the GABA responses are potentiated by the neurosteroid allopregnanolone. In a final commentary, we formulated the mathematical relation between Cl– conductance, KCC2-mediated Cl– extrusion capacity and steady-state [Cl–]i. In summary, the present thesis (i) clarifies how well common electrophysiological methods describe [Cl–]i and gCl, (ii) provides a novel method for quantifying gCl in cell membranes and (iii) clarifies the roles of the ECM, ion channels and ion transporters in the control of [Cl–]i homeostasis and GABAAR-mediated signaling in central neurons.

Cette thèse vise à comprendre le risque de fuite d’informations personnelles sur un réseau social. Nous étudions les violations potentielles de la vie privée, concevons des attaques, prouvons leur faisabilité et analysons leur précision. Cette approche nous aide à identifier l’origine des menaces et constitue un premier pas vers la conception de contre-mesures efficaces. Nous avons d’abord introduit une mesure de sensibilité des sujets à travers une enquête par questionnaire. Puis, nous avons conçu des attaques de divulgation (avec certitude) des liens d’amitié et des liens d’appartenance aux groupes sur “Facebook”. Ces attaques permettent de découvrir le réseau local d’une cible en utilisant uniquement des requêtes légitimes. Nous avons également conçu une technique d’échantillonnage pour collecter rapidement des données utiles autour d’une cible. Les données collectées sont ensuite représentées par des graphes et utilisées pour effectuer des inférences d’attributs (avec incertitude). Pour augmenter la précision des attaques, nous avons conçu des algorithmes de nettoyage. Ces algorithmes quantifient la corrélation entre les sujets, sélectionnent les plus pertinents et permettent de gérer la rareté (sparsity) des données. Enfin, nous avons utilisé un réseau de neurones pour classer les données et déduire les valeurs secrètes d’un attribut sensible d’une cible donnée avec une précision élevée mesurée par AUC sur des données réelles. Les algorithmes proposés dans ce travail sont inclus dans un système appelé SONSAI qui aide les utilisateurs finaux à contrôler la collecte d’informations sur leur vie privée / In this thesis we shed the light on the danger of privacy leakage on social network. We investigate privacy breaches, design attacks, show their feasibility and study their accuracies. This approach helps us to track the origin of threats and is a first step toward designing effective countermeasures. We have first introduced a subject sensitivity measure through a questionnaire survey. Then, we have designed on-line friendship and group membership link disclosure (with certainty) attacks on the largest social network “Facebook”. These attacks successfully uncover the local network of a target using only legitimate queries. We have also designed sampling techniques to rapidly collect useful data around a target. The collected data are represented by social-attribute networks and used to perform attribute inference (with uncertainty) attacks. To increase the accuracy of attacks, we have designed cleansing algorithms. These algorithms quantify the correlation between subjects, select the most relevant ones and combat data sparsity. Finally, we have used a shallow neural network to classify the data and infer the secret values of a sensitive attribute of a given target with high accuracy measured by AUC on real datasets. The proposed algorithms in this work are included in a system called SONSAI that can help end users analyzing their local network to take the hand over their privacy

Duas metodologias que podem ser utilizadas na localização de defeitos em cabos isolados de alta tensão do tipo Oil Filled (OF) foram analisadas. As metodologias descritas têm como princípio a localização de vazamentos de óleo, ou seja, todo defeito seguido de vazamento de óleo poderá ser localizado a partir das mesmas. A primeira metodologia é baseada no congelamento dos cabos OF, com a linha desenergizada, a fim de localizar vazamentos de óleo de cabos OF a partir de 300 litros por mês. A segunda metodologia é baseada na utilização de traços de gás perfluorcarbono Perfluorocarbon Tracer (PFT), através de um sistema montado com equipamentos que permitem realizar a localização de vazamentos de óleo de cabos OF a partir de 100 litros por mês, sem a necessidade de desligamento da linha subterrânea. Esta dissertação propõe algumas melhorias na metodologia do congelamento e apresenta as primeiras experiências de utilização do PFT no Brasil para localização de vazamentos de óleo. / Two methods that can be used to locate faults in Oil Filled (OF) cables were analyzed. The methods described have the principle of oil leak location. All defects followed by oil leakage can be located using the same. The first method is based in OF cables freezing, with the line outage, in order to locate oil leaks from 300 liters per month and above. The second method is based on the use of tracer gas - Perfluorocarbon Tracer (PFT) and devices that allow to perform the location of oil leaks from 100 liters per month, without the need of underground line outage. This paper proposes some improvements for the freezing method and presents the first experiments in Brazil using PFT to locate oil leakage.