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Effect of dwell (hold) time on high temperature fatigue crack growth of AM components / Effekt av uppehållstid (hålltid) på utmattningsspricktillväxt vid hög temperatur hos AM-komponenterVenkatesan, Hemanth January 2023 (has links)
GKN Aerospace AB, Sweden (GAS) is one of the leading companies taking up the charge in manufacturing components using Additive Manufacturing(ed) (AM) techniques in the aerospace sector. They are a hub of engineering and they are a supplier of engine and engine components to the world’s leading aero-engine manufacturers, and airframes to civil and military aircraft manufacturers. A phenomenon that is of interest to designers at GAS is the effects of dwell times on high temperature fatigue, especially how this phenomenon affects the fatigue properties of Laser Powder Bed Fusion (LPBF) Inconel 718 (IN718). IN718 is a versatile alloy that can be used at relatively high temperatures and has excellent weldability and is one of the newer materials replacing expensive materials such as Titanium (and its alloys) in the aerospace industry. The aerospace industry has been pushing for an increase in parts manufactured using AM processes because of the advantage the AM process grants to the production process, however a new manufacturing process for an industry needs to be studied and researched from a failure perspective, i.e. the prominent mode of failure for components manufactured using AM and the underlying factors influencing the failure mechanism must be studied. This thesis explores a solution to predict the life of components based on experimental crack propagation tests wherein the test specimens were subjected to the phenomenon mentioned above. A literature survey was conducted researching ways to model this phenomenon and the factors affecting it. The methods found in the literature survey were far too complex to model for the purposes of this thesis, additionally the methods described in the literature were empirical methods describing the phenomenon, rather than a fundamental study of factors causing the phenomenon and ways to model their influence on the life of the component. Hence, a simple method based on the Palmgren-Miner linear damage summation rule which was coded in the form of a FORTRAN code was utilized to compute the life of the components. Software runs predicting life of physical experiments were conducted and inferences about the predictive method were drawn. The limitations of this method were understood and possible solutions were explored, based on which conclusions were drawn regarding the method’s efficacy in predicting the life of the specimens that underwent dwell loading during fatigue cycling. Finally, the method was applied to a case study to understand the effectiveness of the method. / GKN Aerospace AB, Sverige (GAS) är ett av de ledande företagen som tar upp kampen vid tillverkning av komponenter med hjälp av additiv tillverkning (AM) inom flyg- och rymdsektorn. De är ett nav för ingenjörskonst och de är en leverantör av motorer och motorkomponenter till världens ledande tillverkare av flygmotorer, och civila och militära flygplanstillverkare. Ett fenomen som är av intresse för designers på GAS är effekterna av uppehållstider på högtemperaturutmattning, särskilt hur detta fenomen påverkar utmattningen egenskaper hos Laser Powder Bed Fusion (LPBF) Inconel 718 (IN718). IN718 är en mångsidig legering som kan användas vid relativt höga temperaturer och har utmärkt svetsbarhet och är ett av de nyare materialen som ersätter dyra material såsom titan (och dess legeringar) inom flygindustrin. Flygindustrin har drivit på för en ökning av delar som tillverkas med additiva tillverkningsprocesser på grund av den fördel som tillverkningsprocessen ger en ny tillverkningsprocess för en industri behöver dock studeras och forskat ur ett misslyckandeperspektiv, dvs. det framträdande sättet att misslyckas för komponenter som tillverkats med hjälp av additiv tillverkning och de bakomliggande faktorer som mekanismen måste studeras. Denna avhandling utforskar en lösning för att förutsäga livslängden för komponenter baserat på experimentella sprickutbredningstester där provexemplaren utsattes för fenomenet som nämns ovan. En litteraturstudie genomfördes för att undersöka olika sätt att modellera detta fenomenet och de faktorer som påverkar det. Metoderna som framkom i litteraturstudien var alldeles för komplexa för att modellera för denna avhandling, dessutom är metoderna som beskrivits i litteraturen var empiriska metoder som beskriver fenomenet, snarare än en grundläggande studie av de faktorer som orsakar fenomenet och sätt att modellera deras inverkan på komponentens livslängd. Därav en enkel metod baserad på Palmgren-Miners linjära skadesummeringsregel som kodades i form av en FORTRAN-kod användes för att beräkna livslängden för komponenterna. Programvarukörningar som förutspådde livslängden för fysiska experiment genomfördes och slutsatser om den prediktiva metoden drogs. Begränsningarna med denna metod förstods och möjliga lösningar utforskades. Som låg till grund för de slutsatser som drogs om metodens effektivitet när det gäller att förutsäga livslängden för de prover som genomgick uppehållsbelastning underutmattningscykling. Slutligen tillämpades metoden på en fallstudie för att förstå effektiviteten avmetod.
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Study on the analysis of gastrointestinal positional variations and the efficacy of online adaptive radiation therapy for improving the treatment outcomes of locally advanced pancreatic cancer / 局所進行膵癌に対する放射線治療成績の向上を目的とした消化管位置の変動解析と即時適応放射線治療の有用性に関する研究Ogawa, Ayaka 25 September 2023 (has links)
京都大学 / 新制・課程博士 / 博士(医学) / 甲第24884号 / 医博第5018号 / 新制||医||1068(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 鈴木 実, 教授 小濱 和貴, 教授 中島 貴子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
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MED SJÄLVET SOM STÖDJANDE VÄGVISARE, CHEFERS UPPLEVELSE AV LEDARSKAPSUTBILDNINGEkroth, Anna, Petrini, Jeanette January 2018 (has links)
Ledarskap har en inverkan på medarbetarnas hälsa och påverkar arbetsprestationen. Utifrån detta erbjuder man i Mora kommun sina chefer att genomgå en ledarskapsutbildning. Syftet med vår kvalitativa intervjustudie är att undersöka ledares förväntningar och upplevelse av utbildningen samt syn på och upplevelse av självstöd. Fem chefer, två kvinnor och tre män i åldern 40 - 60 år intervjuade före och efter ledarskapsutbildningen. Intervjuerna var semistrukturerade. Samtalen bandades och transkriberades. Därefter kodades materialet, dels genom en manuell reducering, dels genom kodning/synteser med stöd av Open Code. Ur detta har teman extraherats. Resultatet visar att ledarna var positiva till innehållet och upplägget i utbildningen. Förväntan om att få redskap för praktiskt bruk och inre redskap infriades. Bekräftelse och självinsikt har varit viktigt och att diskutera och spegla sig för reflektion. Synen på självstöd menar ledarna handlar om förmågan att vänta in, backa, att lyssna klart och ta stöd utifrån samt att våga tro på sig själv. Två av ledarna säger sig ha utvecklat sitt självstöd under utbildningen. Utbildningen har bidragit till att man känner sig säkrare och litar mer på sig själv. Tre ledare tycker inte att självstödet utvecklats. Att processen fortsätter efter avslutad utbildning och att detta sanktioneras uppifrån anses avgörande. / Leadership has an impact on employee health and supports better work performance. For this reason, Mora municipality managers offer a leadership program. The purpose of our qualitative interview study was to investigate leaders' expectations and experience of a leadership program, as well as their perspective on self-support. Five leaders, two women and three men aged 40-60 years were interviewed before and after the program. The interviews were semi structured. The talks were electronically recorded and transcribed. The material was encoded, partly by manual reduction, partly by coding / syntheses supported by Open Code. From this the themes have been extracted. The result shows that the leaders were positive about the content and layout of the leadership program. The expectation of getting tools for practical use and internal readiness was fulfilled. Affirmation and self-awareness have been important to discuss as a subject for reflection. The leaders define self-support as the ability to wait, hold back, to listen clearly and to take support from outside, and to believe in oneself. Two of the leaders express that they have evolved their self-support during the program. The program has contributed to feel more safe and to have trust in themselves. Three leaders do not experience that self-support has evolved. That the process continues after completed the program and sanctioned from above is considered crucial.
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Les effets de la multibancarisation sur le financement des PME par les banques / The effects of multibancarisation on SME financing by banksBadreddine, Ayman 12 May 2011 (has links)
La théorie bancaire récente a bien mis en évidence l'avantage comparatif des banques dans l'octroi du crédit aux petites et moyennes entreprises. La dépendance des PME vis-à-vis du financement bancaire est caractérisée par une asymétrie d'information due à l'opacité des firmes. Afin d'échapper à la surveillance de la banque prêteuse, les entreprises se dirigent vers une multibancarisation comme étant d'une part un contrat d'assurance implicite contre le risque de rationnement et d'une autre part une stratégie de diversification des sources de financement. Cette stratégie élimine également le risque de capturation (Hold-up problem) provenant de l'avantage informationnel détenu par la banque prêteuse et assure des conditions de crédits plus favorables. Ce travail de recherche teste et analyse les effets de la relation durable et de la multibancarisation sur les conditions de crédits. Après une présentation des fondements théoriques nous testons, sur un échantillon de 150 PME libanaises, l'effet du financement relationnel multibancaire respectivement sur le coût du crédit, le rationnement du crédit et les garanties demandées. Nous testons de même l’effet de la consolidation bancaire sur la propension des PME à diversifier leurs relations bancaires. / The recent banking theory highlights the comparative advantage of banks in financing SME (Small and Medium-Sized Enterprises. The dependence of the SME from the banking financing is mainly due to their information opacity. To escape the permanent control of the banks, companies go to a multi-banking relationship as an implicit insurance contract against the availability risk but also as an efficient way to diversify sources of funding. This strategy also eliminates the risk of capturation (Holdup Problem) resulting from the informative advantage detained by banks and insures more favorable credit terms. This research tests and analyzes the effects of the long-lasting relation and the multi-banking relationships on credit terms. After a detailed presentation of the literature review when we developed the main theoretical concepts we tested our hypothesis on a sample of 150 Lebanese SME firms. Our empirical works was focused on the effect of the multi-banking financing respectively on the credit cost, on credit availability and on collaterals. We also tested the effect of banking Mergers and acquisitions on SME’s intention to diversify their banking relations.
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Nyintroduktioner på svenska handelsplatser : Har nyintroduktioner genererat högre avkastning än NASDAQ OMXSPI? / Initial Public Offerings on Swedish marketplaces : Have IPOs created higher returns than NASDAQ OMXSPI?Karpov, Boris, Klevenstedt, Johan January 2011 (has links)
Denna studie har genomförts i syfte att undersöka huruvida nyintroduktioner generar en överavkastning i förhållande till OMXSPI på svenska handelsplatser under en börsuppgång och en börsnedgång för olika tidsintervall och branscher. Studien har undersökt nyintroduktioner genomförda under tidsperioden Q1 2004 till Q2 2009. Syftet har för avsikt att utmynna i huruvida nyintroduktioner vid svenska handelsplatser är effektiva och om investerare kunnat utnyttja eventuella ineffektiviteter som investeringsstrategier. Undersökningen är en eventstudie baserad på en kvantitativ metod där korrigerade historiska aktiekurser har inhämtats och beräkningar har genomförts med hjälp av två metoder, den genomsnittliga abnormala avkastningen och den genomsnittliga abnormala avkastningen för en buy-and-hold strategi, för att säkerställa en hög validitet i studien. Slutsatsen påvisar att investerare som investerat i nyintroduktioner på AktieTorget under börsuppgången hade kunnat utnyttja den något lägre grad av effektivitet utifrån en buy-andhold strategi på tre månader och erhållit en genomsnittlig signifikant överavkastning gentemot OMXSPI på 32,6 procent. En investerare som valt att investerare i nyintroduktioner utifrån en buy-and-hold period på tre månader på Alternativa Aktiemarknaden under börsnedgången hade i genomsnitt erhållit en signifikant överavkastning på 11,8 procent. För den investeraren som inte tagit hänsyn till när introduktionen genomförts och investerat i nyintroduktioner på AktieTorget utifrån en buy-and-hold period på en månad hade i genomsnitt erhållit en signifikant överavkastning på 18,2 procent.
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Contribution au développement d’un banc de mesures temporelles 4-canaux pour la caractérisation avancée de composants et de sous-systèmes RF non linéaires / Contribution to the development of a 4-channel time -domain measurement set-up for advanced characterization of RF non-linear components and subsystemsAyari, Lotfi 12 December 2016 (has links)
Les communications futures pour les applications civiles et militaires utilisent des signaux modulés complexes large bande qui seront émis à travers des amplificateurs de puissance multivoie de type DOHERTY qui devront avoir des performances en puissance, rendement, OBO et largeur de bande qui constituent aujourd’hui un véritable défi à relever. Pour ce faire les concepteurs ont besoin d’outils de caractérisation temporelle permettant la mesure normalisées et l’optimisation des tensions et courants aux accès des dispositifs non linéaires sous pointes ou connectorisés. Ce travail de thèse a permis de mettre en œuvre cet outil de caractérisation temporelle qui a été utilisé pour répondre à des besoins spécifiques pour la modélisation de transistor, pour l’optimisation de leur fonctionnement en termes de stabilité impulsion à impulsion, pour la recherche des conditions optimales de leur fonctionnement dans un amplificateur de type Doherty. Pour cette mise en œuvre une modélisation mathématique des échantillonneurs a été réalisée pour évaluer leurs performances et choisir le mieux adapté à la mesure temporelle RF. Des procédures d’étalonnages rigoureuses ont été développées pour obtenir simultanément des formes d’ondes temporelles calibrées à spectre très large (Basse fréquences jusqu’aux Hyperfréquences). / The future communications for civil and military applications will use complex wideband modulated signals to be transmitted through multi-channel DOHERTY power amplifiers which should have high performance in terms of power, efficiency, OBO, and bandwidth. In order to meet these stringent requirements, designers need time-domain characterization tools for calibrated measurements and for optimizing voltages and currents at both ports of non-linear connectorized or on-wafer devices. This work successfully implements time-domain characterization tools used to meet specific needs for transistor modeling, to optimize their operation in terms of pulse to pulse stability, and to search optimal conditions of their operation modes in a Doherty power amplifier. For this implementation, mathematical modeling is performed to evaluate sampler’s performances in terms of time-domain sampling efficiency in order to choose the best suited sampling architecture for RF time-domain measurements. Rigorous calibration procedures have been developed to obtain simultaneously full time-domain calibrated waveforms (from low Frequencies to Microwave frequencies).
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Essays on social influences in decision makingKC, Raghabendra Pratap January 2018 (has links)
This dissertation reports a series of studies on social influences in decision making with wide ranging marketing implications in areas such as gamification initiatives, participative pricing mechanisms, and charity fundraising strategies. The body of this work comprises of three indepth, stand-alone studies. The first study, "Contagion of the Competitive Spirit: The Influence of a Competition on Non-Competitors", investigates the influence of a competition on noncompetitors who do not participate in it but are aware of it. In a series of experimental studies, the study shows that the mere awareness of a competition can affect a non-competitor's performance in similar tasks. These experiments provide confirmatory and process evidence for this contagion effect, showing that it is driven by heightened social comparison motivation due to mere awareness of the competition. In addition, the study finds evidence that the reward level for the competitors could moderate the contagion effect on the non-competitors. The second study, "The Negative Effects of Precommitment on Reciprocal Behaviour: Evidence from a Series of Voluntary Payment Experiments", examines the effects of precommitment on reciprocal behaviour towards a forthcoming benefit. Through a series of experiments in several countries, the study shows that precommitment often weakens reciprocal behaviour. In two field experiments, a laboratory and an online experiment, the study finds consistent evidence that voluntary payment amounts decrease for individuals who are asked to precommit their payment. The results from a final online trust-game experiment support the posited mental-accounting mechanism for the effect. The third study, "Hold-Up Induced by Demand for Fairness: Theory and Experimental Evidence", explores the domain of hold-up and fairness concerns. While recent research suggests that fairness concerns could mitigate hold-up problems, this study proposes a starkly opposite possibility: that fairness concerns can also induce hold-up problems and thus significant inefficiencies. The study reports theoretical analysis and experimental evidence of hold-up in scenarios in which it will not occur if agents are purely self-interested, but could occur if they care about fairness at ex post negotiation.
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日系液晶顯示器關鍵材料廠商在台灣市場之策略行銷分析: 以4C架構分析 / Strategic marketing 4C analysis of Japanese LCD key component’s materials manufacturers in the Taiwan market松岡志保, Matsuoka Shiho Unknown Date (has links)
TFT-LCD(薄膜電晶體液晶顯示器)是台灣全力發展的重點產業。TFT-LCD 產業特徵是專業分工產業,LCD產業價值鏈可分成上游材料廠商、中游面板廠商、下游應用廠商。主要的上游零件及材料包括玻璃基板(glass substrate)、彩色濾光片(color filter)、偏光板/膜(polarizer)、背光模組(backlight module)、驅動IC(Driver IC)、配向膜(alignment layer)。
LCD面板生產所需要的這些原材料占面板生產總成本的70%以上。對面板製造商來說,透過整合減少成本成為一個重要的議題。許多面板的關鍵零組件是設計導入(design in)的產品,對於面板設計,需要配合製造商的要求和規格。所以面板廠商和關鍵零組件廠商之間的快速溝通和反應是非常重要。
目前部分材料是從國外進口的,其中配向膜是日商擁有90%的市佔率。雖然LCD面板成本結構中的比重不高,但是液晶配向膜是決定液晶顯示器面板品質的關鍵材料。主要的配向膜廠商分別是日產化學和JSR。雙方都是日商的化學公司。JSR是2005年投入台灣市場,設立JSRmicro(台灣捷時雅邁科股份有限公司),日產化學則是2010年才進入台灣市場。而且日產化學是液晶配向膜的先鋒者,10年前的市占率大約80%,但是今年降低到50%。日產化學進來台灣時,透過日系綜合商社來交易。而JSR在台灣則是透過台灣的中間商(華立通路商)來交易。
本研究以日系液晶顯示器關鍵材料配向膜廠商「台灣日產化學」為實例,進行專業訪談。探討台灣日產化學之中游面板廠商的產業鏈,並希望運用邱志聖(2010)之策略行銷4C架構分析,進行深入探討日產化學在台灣市場中,如何降低台灣LCD面板廠商的交易成本包含外顯單位效益成本、資訊搜尋成本、道德危機成本、專屬陷入成本,進而了解此公司的競爭優勢,繼而進行跟競爭對手的4C成本比較分析,提供個案公司建議。
本研究目的為了解:
1.日產化學跟客戶之間的4C關係
2.日產化學與通路商之間的關係
3.日產化學跟競爭對手(JSR)的作法比較
研究結果發現:
1.中間商的選擇、數量、提供的產品種類多寡,以及中間商提供的服務都會影響到日產化學對面板廠商的交易成本。
2.相同產業內供應商提供的產品種類多寡會影響到對面板廠商以及中間商的交易成本。
3.製造商之知名度的高低會影響到中間商的選擇權力。 / TFT-LCD (thin film transistor liquid crystal display) is one of the key industries in Taiwan. TFT-LCD industry is characterized as a specialization industry. The LCD industry value chain can be divided into upstream materials manufacturers, the midstream panel manufacturers, and downstream application vendors. Upstream material parts include glass substrate, color filter, polarizer film, backlight module, the driver IC, and alignment layer.
These essential components needed in LCD panel production account for more than 70% of the total cost in panel production. Therefore an important issue for panel makers is to reduce costs through integration. As many of the key components of the panel is the “design in product”, which need to be designed according to manufacturer's requirements and specifications, rapid communication and response between panel manufacturers and key components manufacturers is very important.
Some materials are imported from abroad; Japanese companies have 90% market share in the alignment film market. Although the proportion of the cost structure of the LCD panel is not high, but the alignment layer is the key material to determine the quality of liquid crystal display panel. Two main alignment film makers are Nissan Chemical and JSR. They both are Japanese chemical companies. JSR devotes into Taiwanese market in 2005, and established JSRmicro. Nissan Chemical started its business in Taiwan at 2010, by establishing Taiwan Nissan Chemical. Nissan Chemical is the pioneer in liquid crystal alignment film and once had approximately 80 percent of market share 10 years ago, but it has declined to 50% as of now. Nissan Chemical transact through Japanese Sogo Shosha in Taiwai. JSR transact through Taiwanese intermediaries (Wahlee distributor) in Taiwan.
In this study, Japanese liquid crystal alignment layer manufacturer Taiwan Nissan Chemical were professionally interviewed, then explored between Taiwan Nissan Chemical and the panel manufacturers’ industry chain. This study will also apply strategic marketing 4C framework for analysis, then conduct an in-depth investigation on how Taiwan Nissan Chemical reduces transaction costs for Taiwan LCD panel manufacturers, illustrate the company's competitive advantage through the transaction costs analysis, including buyer utility cost, information searching cost, moral hazard cost, and asset specificity cost, and lastly compare with the competitor’s transaction cost.
The purposes of this research are:
1. The 4C relationship between Nissan Chemical and the client
2. The relationship between Nissan chemical and the distributors
3. The 4C comparison between Nissan Chemical and the competitor (JSR)
The results of study show that:
1. A choice of intermediaries, the number of intermediaries, the number of product that intermediaries offer, and the services intermediaries provide will affect the transaction costs of Nissan Chemical for panel makers.
2. The product range provided by the suppliers within the same industry would affect the transaction costs of panel makers and intermediaries,
3. The well-known level of the manufacturer will affect the power of choice for intermediaries.
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High Speed On-Chip Measurment Circuit / Inbyggd krets för höghastighetsmätning på chipStridfelt, Arvid January 2005 (has links)
<p>This master thesis describes a design exploration of a circuit capable of measuring high speed signals without adding significant capacitive load to the measuring node. </p><p>It is designed in a 0.13 CMOS process with a supply voltage of 1.2 Volt. The circuit is a master and slave, track-and-hold architecture incorporated with a capacitive voltage divider and a NMOS source follower as input buffer to protect the measuring node and increase the input voltage range. </p><p>This thesis presents the implementation process and the theory needed to understand the design decisions and consideration throughout the design. The results are based on transistor level simulations performed in Cadence Spectre. </p><p>The results show that it is possible to observe the analog behaviour of a high speed signal by down converting it to a lower frequency that can be brought off-chip. The trade off between capacitive load added to the measuring node and input bandwidth of the measurment circuit is also presented.</p>
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High Speed On-Chip Measurment Circuit / Inbyggd krets för höghastighetsmätning på chipStridfelt, Arvid January 2005 (has links)
This master thesis describes a design exploration of a circuit capable of measuring high speed signals without adding significant capacitive load to the measuring node. It is designed in a 0.13 CMOS process with a supply voltage of 1.2 Volt. The circuit is a master and slave, track-and-hold architecture incorporated with a capacitive voltage divider and a NMOS source follower as input buffer to protect the measuring node and increase the input voltage range. This thesis presents the implementation process and the theory needed to understand the design decisions and consideration throughout the design. The results are based on transistor level simulations performed in Cadence Spectre. The results show that it is possible to observe the analog behaviour of a high speed signal by down converting it to a lower frequency that can be brought off-chip. The trade off between capacitive load added to the measuring node and input bandwidth of the measurment circuit is also presented.
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