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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.
41

Den militära nyttan med kontrollerbara sjöminsystem : En jämförande fallstudie / The Military utility in controllable sea mines : A comparative study

Östlund, Patrik January 2018 (has links)
Sea mines are a cheap weapons system useful for hindering an opponent’s freedomof movement. Controllable sea mines, that can be activated and deactivated after they havebeen laid out, can be laid out prior to break out of war. The main bulk of sea mines storedtoday in Swedish depots are not controllable. This thesis compares the military utility between two controllable mine systems. The existingM9-system and a system draft based on wireless underwater communication. With theSwedish navy as the military actor using the systems, the comparison is set against abackground scenario of an escalating crisis. In this context the military effectiveness, militarysuitability and affordability of the systems is studied. The results indicate that the KT-system introduced in this study has a slightly greater militaryutility. At the same time, the results point out a number of differences between the systems,which in the end might be of greater use to a decision maker than a summed up rating. / Sjöminor är ett billigt vapensystem som kan användas för att hindra enmotståndares rörelsefrihet. Sjöminor som är kontrollerbara kan aktiveras och stängas av efterfällning vilket möjliggör minering före ett krigsutbrott. Huvuddelen av de minor som idagfinns i svenska förråd är okontrollerbara. Denna studie jämför militär nytta mellan två kontrollerbara sjöminsystem. Det existerandeM9-systemet och ett idésystem baserat på trådlös undervattenskommunikation. Med densvenska marinen som tänkt brukare och mot bakgrund av ett eskalerande krisscenariostuderas vilket av systemen som skulle vara mest militärt effektivt, militärt lämpligt ochsamtidigt ekonomiskt överkomligt. Resultatet indikerar att det i studien presenterade KT-systemet som introduceras i denna studiehar en liten fördel ur ett militärt nyttoperspektiv. Samtidigt visar de på ett antal skillnadermellan systemen vilket i slutänden kan mer användbara för en beslutsfattare än ett sammanvägtbetyg.
42

An interfacial engineering approach towards two-dimensional porous carbon hybrids for high performance energy storage and conversion

Lu, Chenbao, Liu, Shaohua, Zhang, Fan, Su, Yuezeng, Zou, Xiaoxin, Shi, Zhan, Li, Guodong, Zhuang, Xiaodong 17 July 2017 (has links) (PDF)
In order to improve the performance and fundamental understanding of conducting polymers, development of new nanotechnologies for engineering aggregated states and morphologies is one of the central focuses for conducting polymers. In this work, we demonstrated an interfacial engineering method for the rational synthesis of a two-dimensional (2D) polyaniline (PANI) nano-array and its corresponding nitrogen-doped porous carbon nanosheets. Not only was it easy to produce a sandwich-like 2D morphology, but also the thickness, anchored ions and produced various metal phosphides were easily and rationally engineered by controlling the composition of the aqueous layer. The novel structural features of these hybrids enabled outstanding electrochemical capacitor performance. The specific capacitance of the as-produced diiron phosphide embedded nitrogen-doped porous carbon nanosheets was calculated to be as high as 1098 F g−1 at 1 A g−1 and an extremely high specific capacitance of 611 F g−1 at 10 A g−1, outperforming state-of-the-art performance among porous carbon and metal-phosphide-based supercapacitors. We believe that this interfacial approach can be extended to the controllable synthesis of various 2D material coupled sandwich-like hybrid materials with potential applications in a wide range of areas.
43

Nouveaux développements de matériaux électroactifs à base de polymères conducteurs électroniques : Vers une intégration dans des systèmes biomédicaux / New Developments in electroactive materials based on electronic conductive polymers : Towards integration into biomedical systems

Woehling, Vincent 04 May 2016 (has links)
Ces travaux de thèse s’intéressent à la conception et à la mise en forme d’actionneurs à base de polymères conducteurs électroniques dans l’optique d’une utilisation biomédicale. Actuellement, et alors que certaines problématiques récurrentes de légèreté, de flexibilité et de robustesse peuvent être résolues par ces actionneurs, des limitations restreignent encore leurs utilisations dans des dispositifs biomédicaux contrôlables.En premier lieu, nos matériaux composés de réseaux interpénétrés de polymères (RIP) poly (oxyde d’éthylène) (PEO), caoutchouc nitrile (NBR) et de polymère conducteur électronique (PCE) (poly (3,4-éthylènedioxythiophène)) (PEDOT), ont été étudiés en tant que capteur de déformation. Cette propriété est essentielle pour assurer un retour d’informations de nos systèmes dans des utilisations biomédicales exigeantes.Un troisième réseau de polymère à haut module, le polystyrène (PS), a été interpénétré au RIP PEO-NBR dans le but d’améliorer les forces générées par l’actionnement. Un matériau combinant des propriétés de conduction ionique (PEO), viscoélastiques (NBR) et vitreuses (PS) a alors été obtenu. La caractérisation approfondie de ce tri-RIP, l’incorporation du PCE ainsi que l’étude des performances en actionnement ont alors été réalisée.Dans la continuité et dans le cadre d’une collaboration avec le Pr J. Madden (Vancouver, Canada), le matériau ainsi synthétisé a été utilisé dans une mise en forme particulière de cathéter. Ainsi, un tube électroactif PEO-NBR-PS-PEDOT creux, souple, étirable, d’épaisseur homogène et contenant un gradient de rigidité a été réalisé afin de répondre aux différentes problématiques liées à cette géométrie.Enfin, la dernière partie a été dédiée à une mise en forme plus complexe et originale de notre matériau PEO-NBR. En collaboration avec le PERC (Auckland, N-Z), des tapis de microfibres élastomères électroactifs ont été élaborés par électrofilage. Ces matériaux poreux, étirables et robustes ont montré des changements de taille de pores réversibles dans différents électrolytes, y compris biologiquement compatibles. Des applications biomédicales de type filtre à porosité contrôlable ou la stimulation de cellules souches pourraient alors être envisagées. / This PhD work deal with the conception and shaping of actuators based electronic conductive polymers in the context of biomedical use. Currently, while some recurrent problems of lightness, flexibility and robustness can be resolved by these actuators, limitations still restrict their use in biomedical controllable devices.First, our materials composed of interpenetrating polymer networks (IPN) poly (ethylene oxide) (PEO), nitrile butadiene rubber (NBR) and electronically conductive polymer (ECP) (poly (3,4-ethylenedioxythiophene)) (PEDOT) have been studied as a strain sensor. This property is essential to ensure a feedback of our systems in demanding biomedical uses.A third high modulus polymer network, polystyrene (PS), was interpenetrated IPN PEO-NBR in order to improve the forces generated by the actuator. A material combining ionic conductive (PEO), viscoelastic (NBR) and vitreous (PS) properties has been obtained. The detailed characterization of this tri-IPN, the incorporation of the PCE and the study of air-operating performances were then carried out.In continuity and with the collaboration of Pr. J. Madden (Vancouver, Canada), the synthesized material has been used in a particular shaping of catheter. Thus, an electroactive, hollow, flexible, stretchable NBR-PEO-PS-PEDOT tube, with uniform thickness and containing a rigidity gradient has been created in order to solve the various problems associated with this geometry.The last part was dedicated to a more complex and original shaping of our PEO-NBR material. In collaboration with the PERC (Auckland, NZ), electroactive elastomer microfiber mats were prepared by electrospinning. These porous, stretchable and robust materials showed reversible pore size variations in various electrolytes, including biologically compatible. Biomedical applications as filters with controllable porosity or stem cells stimulation could be considered.
44

Digitálně řízený zdroj generující proudové impulzy nastavitelného náběhu a trvání / Digitally controllable power-supply generating current pulses with adjustable rising slope and duration

Dujíček, Martin January 2014 (has links)
Master’s thesis is focused on design of digitally controllable power-supply for generating current pulses with nominal level (few amperes), adjustable rising slope and time of duration. Device uses voltage controlled current source. Control voltage is generated by digital to analog converter. Computer simulations are accomplished for designed electronic circuit and measurement of prototype is done as well.
45

Machine Learning for Classification of Temperature Controlled Containers Using Heavily Imbalanced Data / Maskininlärning för klassificering av temperatur reglerbara containrar genom användande av extremt obalanserad data

Ranjith, Adam January 2022 (has links)
Temperature controllable containers are used frequently in order to transport pharmaceutical cargo all around the world. One of the leading manufacturing companies of these containers has a method for detecting containers with a faulty cooling system before making a shipment. However, the problem with this method is that the model tends to miss-classify containers. Hence, this thesis aims to investigate if machine learning usage would make classification of containers more accurate. Nonetheless, there is a problem, the data set is extremely imbalanced. If machine learning can be used to improve container manufacturing companies fault detection systems, it would imply less damaged and delayed pharmaceutical cargo which could be vital. Various combinations of machine learning classifiers and techniques for handling the imbalance were tested in order to find the most optimal one. The Random Forest classifier when using oversampling was the best performing combination which performed about equally as good as the company’s current method, with a recall score of 92% and a precision score of 34%. Earlier there were no known papers on machine learning for classification of temperature controllable containers. However, now other manufacturing companies could favourably use the concepts and methods presented in this thesis in order to enhance the effectiveness of their fault detection systems and consequently improve the overall shipping efficiency of pharmaceutical cargo. / Temperatur reglerbara containrar används frekvent inom medicinsk transport runt om i hela världen. Ett ledande företag som är tillverkare av dessa containrar använder sig av en metod för att upptäcka containrar med ett felaktigt kylsystem redan innan de hunnit ut på en transport. Denna metod är fungerande men inte perfekt då den tenderar att felaktigt klassificera containrar. Detta examensarbete är en utredande avhandling för att ta reda på om maskininlärning kan användas för att förbättra klassificeringen av containrar. Det finns dock ett problem, data setet är extremt obalanserat. Om maskininlärning kan användas för att förbättra felsökningssystemen hos tillverkare av temperatur reglerbara containrar skulle det innebära mindre förstörda samt mindre försenade medicinska transporter vilket kan vara livsavgörande. Ett urval av kombinationer mellan maskininlärnings modeller och tekniker för att hantera obalanserad data testade för att avgöra vilken som är optimal. Klassificeraren Random Forest ihop med över-sampling resulterade i best prestanda, ungefär lika bra som företagets nuvarande metod. Tidigare har det inte funnits några kända rapporter om användning av maskininlärning för att klassificera temperaturer reglerbara containrar. Nu kan dock andra tillverkare av containrar använda sig av koncept och metoder som presenterades i avhandlingen för att optimera deras felsökningssystem och således förbättra den allmänna effektiviteten inom medicinsk transport.
46

Use of Electrical Coolant Pumps in Scania’s Cooling System / Användning av elektriska kylvätskepumpar i Scanias kylsystem

Srikanth, Sai Aswin January 2019 (has links)
The automotive industry is currently traversing through the electrification wave. Numerous manufacturers are directing focus to electrify their lineup and reduce emissions. In the frontier of heavy duty diesel trucks, electrification of auxiliary units remains an unexplored potential. An optimized cooling system functioning in sync with a controllable electric coolant pump attempts to reduce parasitic losses and emissions. The cooling flow requirements in challenging conditions may also be fulfilled. Although electric coolant pumps are found increasingly in passenger cars, the implication of independently operating them in a heavy duty diesel truck is an important objective to be explored. The purpose of this project is to generate different cooling system layouts coupled with electrical coolant pumps. The performance of these layouts is compared with the volume flows in a standard cooling system. Refined layouts which fulfill the cooling system requirements are chosen for verification. 1-D Simulation is used to correlate and verify the trends of the test rig data. The results show an adequate gain in the total volume flow across distinct layouts with the electric coolant pumps. However, numerous challenges are required to be overcome. / Bilindustrin befinner sig mitt i en våg av elektrifiering. Flertalet tillverkare fokuserar på att elektrifiera sitt produktutbud och att minska utsläppen. Inom forskningen kring tunga transporter med dieseldrivna lastbilar, är elektrifiering av kylsystemet ett outforskat område. Ett optimerat kylsystem som är reglerbart med en elektrisk kylvätskepump skulle potentiellt kunna minska energiförluster och utsläpp. Kravet på flödet av kylvätska vid utmanande driftsfall skulle också kunna bli bättre uppfyllda än för dagens system. Trots att det blir allt vanligare att personbilar har elektriska kylvätskepumpar, så har det inte utforskats vad det innebär att ha reglerbara elektriska kylvätskepumpar i dieseldriva lastbilar. Därför är detta ett viktigt område att utforska. Målet med detta projekt är att skapa olika kylsystemskoncept, där den elektriska kylvätskepumpen är en systemkomponent. Prestandan hos dessa principlösningar jämförs sedan med volymflödet i ett standard kylvätskesystem. Koncept som uppfyller kraven för kylvätskesystemet kommer att bli utvalda för vidare verifiering. 1-D simuleringar används för att hitta samband och verifiera mot trenderna som hittas i resultat från en testrigg. Resultaten visar en förbättring i det totala volymflödet för flera av lösningarna, som har en elektrisk kylvätskepump. Men det finns fortfarande flera utmaningar som behöver övervinnas.
47

Fabrication and Degradation of Electrospun Scaffolds from L-Tyrosine Based Polyurethane Blends for Tissue Engineering Applications

Spagnuolo, Michael 16 May 2011 (has links)
No description available.
48

The Effects of Deployable Surface Topography Using Liquid Crystal Elastomers on Cylindrical Bodies In Flow

Settle, Michael J., Jr 15 May 2023 (has links)
No description available.
49

Adapative Summarization for Low-resource Domains and Algorithmic Fairness

Keymanesh, Moniba January 2022 (has links)
No description available.
50

A Comprehensive Strategy for Controlling the Hip and Knee with a Muscle-Driven Exoskeleton for Mobility after Paraplegia

Chang, Sarah Randall January 2016 (has links)
No description available.

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