The challenges faced in today’s industry require materials capable of working in chemically aggressive environments at elevated temperature, which has fueled the development of oxidation resistant materials. All-Oxide Ceramic Matrix Composites (OCMC) are a promising material family due to their inherent chemical stability, moderate mechanical properties, and low weight. However, limited information exists regarding their behavior when in contact with other high-temperature materials such as superalloys. In this work three sets of tribological tests were performed: two at room temperature and one at elevated temperature (650 °C). The tests were performed in a pin-on-disk configuration testing Inconel 718 (IN-718) pins against disks made with an aluminosilicate geopolymeric matrix composite reinforced with alumina fibers (N610/GP). Two different loads were tested (85 and 425 kPa) to characterize the damage on both materials. Results showed that the pins experienced ~ 100 % wear increase when high temperature was involved, while their microstructure was not noticeably affected near the contact surface. After high temperature testing the OCMC exhibited mass losses two orders of magnitude higher than the pins and a sintering effect under its wear track, that led to brittle behavior. The debris generated consists of alumina and suggests a possible crystallization of the originally amorphous matrix which may destabilize the system. The data suggests that while the composite’s matrix is stable, wear will not develop uncontrollably. However, as soon as a critical load/temperature combination is attained the matrix is the first component to fail exposing the reinforcement to damage which drastically deteriorates the integrity of the component.

Online adolescent friendships and social networking among adolescents are current phenomena that have emerged, and exploded, as part of the digital age and the vast development of communication technologies. The primary aim of this study was to gain knowledge and understanding regarding the nature and quality of online friendships and social networking among adolescents. A sequential explanatory mixed method design, was put to use for the purpose of this study. The quantitative data was collected first in the form of a short survey, by utilising a self-developed questionnaire to obtain a general overview of the social network practices and the forming and maintaining of online friendships among adolescents. Twenty five participants took part in the survey. This study was followed by a qualitative study in the form of interviews, to clarify, elaborate and explain the quantitative findings. Five information rich participants were interviewed. The findings of the empirical investigation revealed that adolescents, being part of the Net Generation, base their concept of socialising with friends on digital and communication technology, especially cell phones. They are connected to their friends 24 hours a day. The sense of safety and support they experience through this constant connectedness strengthens their self-esteem, self-confidence and self-worth and contributes to their identity formation. It is therefore recommended that parents and educators should accept that adolescents live in a virtual world and their new way of socialising, needs to be acknowledged. Parents and educators should adjust accordingly, by getting educated in this field themselves. The Net Generation is a generation who focuses on relationships and collaboration through technology and this should be exploited by anybody who has contact or interacts with the adolescent of today. / Psychology of Education / M. Ed. (Guidance and Counselling)

Ce mémoire examine l'adoption des téléphones mobiles et l'utilisation des messages texte (SMS) par les adolescents chinois, selon la théorie des usages et gratifications et de la recherche sur la communication par ordinateur. Certains champs particuliers de l'utilisation des messages textes par les adolescents chinois, comme le contrôle parental, la circulation des chaînes de messages, la popularité des messages de salutations et l'utilisation répandue des émoticônes ont été étudiés. La fonction sociale des SMS, plus particulièrement des pratiques sociales et des relations émotionnelles des adolescents chinois, a également été explorée. Cette étude est basée sur un sondage réalisé sur le terrain auprès de 100 adolescents chinois. Elle révèle que chez les adolescents chinois, les deux principales raisons pour l'adoption du téléphone mobile sont l'influence parentale et le besoin de communication sociale. Quant à l'utilisation des messages texte, elle répond à sept usages et gratifications : la flexibilité, le coût modique, l’intimité, éviter l'embarras, le divertissement, l'engouement et l'évasion. Il a également été observé que les messages texte jouent un rôle positif dans la construction et l'entretien des relations sociales des adolescents chinois. / This thesis examined the adoption of mobile phones and use of SMS among Chinese teenagers based on the uses and gratification theory and computer-mediated communication research. Specific areas of Chinese teenagers’ SMS use, such as parental control, the circulation of chain messages, the popularity of greeting messages and the wide use of emoticons were studied. The social functions of SMS, especially in Chinese teenagers’ social-emotional practice, were explored as well. This study is based on a field survey conducted among one hundred Chinese teenagers. It reveals that, for Chinese teenagers, the two main reasons for the adoption of mobile phones are parental influence and the need for social communication; the use of SMS corresponds to seven uses and gratifications: flexibility, low cost, privacy, embarrassment avoidance, entertainment, fad and escape. SMS is also used by Chinese teenagers to build and maintain their social relationships.

自一九八Ｏ年代起，現代資訊與通訊科技(Information and Communication Technology or ICT)、電腦中介傳播(Computer-Mediated Communication or CMC)、網際網路(Internet)及全球資訊網(World Wide Web or WWW)的發展和普及化，已被學者、政治人物、以及論者們認為是可用以加強實踐公民參與及民主政治之有效工具。本研究即探討政府如何透過網際網路來提供公民參與機制。 本研究以網際網路之公民參與機制的理論為基礎，建構一個完整的網際網路之公民參與機制，亦即建構一個理想的網路公共論壇版面。並檢視台北市政府於全球資訊網網站上之公共論壇版面的運作現況及其成效，檢驗其中公民參與公共事務價值的實踐程度。最後，將探討網際網路之公民參與機制的實踐會有哪些侷限，應如何加以突破，藉此提供學術界及實務界研究貢獻。 / Since the 1980's, many scholars, statesmen, and researchers have come to realize that the development and popularity of modern Information and Communication Technology (ICT), Computer-mediated Communication (CMC), Internet, and the World Wide Web (WWW) will become the effective mechanism for citizen participation. The main purpose of this research paper is to study how government provides citizen participation through Internet. First, the paper will take the theory of Internet citizen participation to construct an ideal mechanism of Internet citizen participation, i.e., to build an ideal operational procedural of Internet Public Forum. Second, the paper will use Taipei City Government's "Citizen Forum" in the World Wide Web as a case study to compare and analyze this case with the ideal operational procedural of Internet Public Forum. Last, the paper will discuss the constraints of Internet citizen participation, and search for solutions to these constraints.

社交網站，尤其是Facebook，在近幾年使用人口日趨增加，變得非常熱門。本研究觀察到在組織內，許多人運用Facebook這類社交網站與同事維繫人際關係。有趣的是，當Facebook進入組織情境後，這種以電腦中介傳播為基礎的人際互動方式，與實體人際關係模式不同，也迥異於全然線上的人際互動模式，其特殊性進一步帶來組織內人際關係的重要改變。 　　本研究共分三方面來探討Facebook進入組織情境後，對組織內人際關係所造成的改變。首先，受Facebook科技屬性影響，組織成員在Facebook上人際關係樣態根基於「虛實交錯」此一概念。由於同事間相互認識，其人際關係發展歷程從線下的實體互動開始，蔓延到Facebook的線上互動，而眾人在線上互動結果又會再度影響實體關係。換句話說，組織成員在「虛擬」和「實體」不同場域來回擺盪，造成「虛實交錯」情形，也讓組織內人際關係模式產生改變。 　　在這基礎上，本研究進一步發現Facebook「虛實交錯」的人際關係模式展現在兩個層面上。從整體角度來看，當Facebook出現後，在組織內形成另一個人際關係場域，彷彿是辦公室內的「線上茶水間」，組織成員在該場域互動、維繫人際關係的方式與實體茶水間有所不同，有其獨特性，因此我們用「線上茶水間」來描繪Facebook「虛實交錯」下的人際關係場域特性。在線上茶水間，組織成員以大量且多樣化資訊做為連結人際關係基礎，達到不同於實體茶水間的社交功能，如大量且速成的安慰與支持、跨越時空的陪伴感等，也使得線上茶水間的人際關係具有一定特色，例如淺層情感交流等。從個人層次來探討，組織成員的形象在此人際關係場域內也有不同展現方式，當Facebook出現後，它的科技屬性提供組織成員「另一個舞台」，讓個人得以展現出在正式組織場域中難以呈現的某種形象，因此我們用「另一個舞台」來描繪其轉變與特性。然而Facebook終究位於組織體系內，因此組織成員無法扮演一個全新或不真實形象，在舞台上的「演出」難免受到束縛。儘管如此，組織成員仍可透過Facebook調節自己在實體組織場域予人的形象，展現出欲呈現面貌。 / This study discusses the impact and influence of Facebook on interpersonal relationships at the work place. Social networking sites (SNS), Facebook in particular, have grown in popularity in recent years. In addition to personal usage, many use Facebook as a tool to interact with their colleagues in corporate settings. When used in this manner, the mode of interaction is based on computer-mediated communication (CMC), which is distinct from physical interactions or from virtual online interactions. This study focuses on three aspects of Facebook that influence and shape the relationships among employees in a corporation. Firstly, the members of a business organization know each other, so the process of interaction begins with physical acquaintance. The interaction then migrates online through Facebook, which, in turn, shapes the nature of the physical interaction. In other words, aided by technology, the corporate personnel interact both in "virtual (online)" space and in "physical" space, resulting in a mode of interaction that can be called "virtually and physically interlaced" interaction. On this basis, this study examines the effects of "virtually and physically interlaced" interaction from two perspectives. First, from the overview perspective, the introduction of Facebook in a corporate setting creates a space for a new form of interaction, an "online break room" of sorts, in which the corporate personnel's interaction is experienced differently than in a physical break room. Employees in "online break rooms" communicate with each other in multiple modes and methods such as videos, music, forwarded articles and so on. Unlike in a physical break room where the conversations are limited in number and also limited by the necessity of shared space and time, the online break room offers unconstrained space where employees can readily exchange their thoughts, opinions, as well as their feelings with others. The experience creates a new social dimension to the "online break room" at hand that employees can be accompanied by colleagues anytime and anywhere and also be able to receive much comfort and support from the coworkers. However, the level of communication remains superficial because employees do not interact in person. Second, from the individual perspective, an employee's experience of interaction with others in an "online break room" is changed. The introduction of Facebook in a corporate setting provides its personnel an alternate platform to express themselves more personally, in ways which may have been difficult to do in a rigid and formal business environment. We use the term "alternative stage" to describe the changes in interactions afforded by the addition of another platform. On the "main stage" of a conventional corporate environment, a person may feel compelled to conform to the corporate culture, and the expression of individuality may be limited, which results in a projected image that tends to be formal. In such an environment, Facebook becomes a stage/place where individuals can express and highlight their own personality or hobbies, giving a more personal and informal image to adjust the physical and conventional formal images.

Ce mémoire examine l'adoption des téléphones mobiles et l'utilisation des messages texte (SMS) par les adolescents chinois, selon la théorie des usages et gratifications et de la recherche sur la communication par ordinateur. Certains champs particuliers de l'utilisation des messages textes par les adolescents chinois, comme le contrôle parental, la circulation des chaînes de messages, la popularité des messages de salutations et l'utilisation répandue des émoticônes ont été étudiés. La fonction sociale des SMS, plus particulièrement des pratiques sociales et des relations émotionnelles des adolescents chinois, a également été explorée. Cette étude est basée sur un sondage réalisé sur le terrain auprès de 100 adolescents chinois. Elle révèle que chez les adolescents chinois, les deux principales raisons pour l'adoption du téléphone mobile sont l'influence parentale et le besoin de communication sociale. Quant à l'utilisation des messages texte, elle répond à sept usages et gratifications : la flexibilité, le coût modique, l’intimité, éviter l'embarras, le divertissement, l'engouement et l'évasion. Il a également été observé que les messages texte jouent un rôle positif dans la construction et l'entretien des relations sociales des adolescents chinois. / This thesis examined the adoption of mobile phones and use of SMS among Chinese teenagers based on the uses and gratification theory and computer-mediated communication research. Specific areas of Chinese teenagers’ SMS use, such as parental control, the circulation of chain messages, the popularity of greeting messages and the wide use of emoticons were studied. The social functions of SMS, especially in Chinese teenagers’ social-emotional practice, were explored as well. This study is based on a field survey conducted among one hundred Chinese teenagers. It reveals that, for Chinese teenagers, the two main reasons for the adoption of mobile phones are parental influence and the need for social communication; the use of SMS corresponds to seven uses and gratifications: flexibility, low cost, privacy, embarrassment avoidance, entertainment, fad and escape. SMS is also used by Chinese teenagers to build and maintain their social relationships.

国立情報学研究所で電子化したコンテンツを使用している。

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-28T21:49:04Z No. of bitstreams: 1 KARINE CASTRO NÓBREGA – DISSERTAÇÃO (UAEMa) 2015.pdf: 1849613 bytes, checksum: c5a145f0dd677d54aab0ed55f6ccc4e9 (MD5) / Made available in DSpace on 2018-06-28T21:49:04Z (GMT). No. of bitstreams: 1 KARINE CASTRO NÓBREGA – DISSERTAÇÃO (UAEMa) 2015.pdf: 1849613 bytes, checksum: c5a145f0dd677d54aab0ed55f6ccc4e9 (MD5) Previous issue date: 2015-02-23 / CNPq / A perfuração de poços de petróleo pode danificar fortemente a formação, incluindo a região de interesse: o reservatório. Perfurar sem que se danifique o reservatório caracteriza-se como um grande desafio, e por isso, tem sido estimulado o desenvolvimento de tecnologias de fluidos e otimização de processos de perfuração, incluindo, por exemplo, o uso de fluidos argilosos com vistas à minimização de perdas excessivas de filtrado para as formações permeáveis. Desta forma, este trabalho teve como objetivo avaliar a influência dos aditivos carboximetilcelulose (CMC) e calcita (CaCO3) e suas interações nas propriedades de filtração de fluidos de perfuração argilosos. Para tanto, foi utilizada uma amostra de argila bentonítica, comercialmente conhecida por Volclay, duas amostras de CMC com diferentes massas molares (CMC 1 (9,0 x 104g/mol) e CMC 2 (2,5 x 105g/mol)) e mesmo grau de substituição (DS = 0,7) e, duas amostras de calcita (CaCO3), com diferentes diâmetros médios de partículas e curvas de distribuição em tamanho. Foram realizadas a caracterização física e mineralógica da amostra de argila e a caracterização granulométrica das amostras de calcita, em seguida determinadas as propriedades reológicas (viscosidades aparente (VA) e plástica (VP), limite de escoamento (LE) e força gel (FG)) e de filtração (volume de filtrado (VF), volume de filtrado corrigido (VFcorr), spurt loss (SPL), espessura (h) e permeabilidade (k) do reboco e poder de retenção (R)) dos fluidos argilosos estudados. Os resultados evidenciaram que os fluidos estudados apresentaram comportamento pseudoplástico e os fluidos argilosos preparados com elevada concentração de CMC 2 (2g/350mL de água) apresentaram melhores valores de propriedades reológicas, pois estas propriedades são fortemente influenciadas pelo grau médio de polimerização dos aditivos poliméricos. A aditivação de fluidos argilosos com carboximetilcelulose de baixa massa molar e com calcita de granulometria fina conferiu aos fluidos melhor desempenho na melhoria das propriedades de filtração. Isto aconteceu, porque no meio aquoso a CMC 1 em elevada concentração associada a calcita 1 conduziu a menores valores de VF, h e k e, elevados valores de R. / The drilling of oil wells can greatly damage the formation, including the region of interest: the reservoir. Drilling without damaging the reservoir is characterized as a big challenge, and therefore, has been stimulated the development of fluid technologies and optimization of drilling processes, including, for example, the clay fluids use aiming at minimization excessive losses of the filtrate into the permeable formations. Thus, this study aimed to evaluate the influence of additives carboxymethylcellulose (CMC) and calcite (CaCO3) and their interactions in the filtration properties of clay drilling fluids. For this, it was used a sample of bentonite clay, commercially known by Volclay, two samples of CMC with different molecular weight (CMC 1 (9,0 x 104g/mol) and CMC 2 (2,5 x 105g/mol) ) and the same degree of substitution (DS = 0,7) and two samples of calcite (CaCO3) with different average diameters of particles and size distribution curves. It was done the physical and mineralogical characterization of the clay sample and the particle size characterization of the calcite samples it was also determined the rheological properties (apparent viscosity (AV) and plastic (PV), yield limit (YL) and gel strength (GS)) and of filtration (filtrate volume (FV), filtrate volume corrected (FVcorr), spurt loss (SPL), cake thickness (h) and permeability (k) and retaining power (R)) of the studied clay fluids. The results showed that the studied fluids showed pseudoplastic behavior and clay fluids prepared with high concentration of CMC 2 (2g/350mL of water) showed better values of rheological properties, because these properties are strongly influenced by the average degree of polymerization of polymeric additives. The additived clay fluids with low molecular weight carboxymethylcellulose and with fine granulometry calcite gave the fluids best performance in improving the filtration properties. This happened because in the aqueous medium the CMC 1 in high concentration associated at calcite 1 led at lower values of FV, h and k and high values of R.

This thesis aims at improving our knowledge on swirl combustors. The work presented here is based on Large Eddy Simulations (LES) coupled to an advanced combustion model: the Conditional Moment Closure (CMC). Numerical predictions have been systematically compared and validated with detailed experimental datasets. In order to analyze further the physics underlying the large numerical datasets, Proper Orthogonal Decomposition (POD) has also been used throughout the thesis. Various aspects of the aerodynamics of swirling flames are investigated, such as precession or vortex formation caused by flow oscillations, as well as various combustion aspects such as localized extinctions and flame lift-off. All the above affect flame stabilization in different ways and are explored through focused simulations. The first study investigates isothermal air flows behind an enclosed bluff body, with the incoming flow being pulsated. These flows have strong similarities to flows found in combustors experiencing self-excited oscillations and can therefore be considered as canonical problems. At high enough forcing frequencies, double ring vortices are shed from the air pipe exit. Various harmonics of the pulsating frequency are observed in the spectra and their relation with the vortex shedding is investigated through POD. The second study explores the structure of the Delft III piloted turbulent non-premixed flame. The simple configuration allows to analyze further key combustion aspects of combustors, with further insights provided on the dynamics of localized extinctions and re-ignition, as well as the pollutants emissions. The third study presents a comprehensive analysis of the aerodynamics of swirl flows based on the TECFLAM confined non-premixed S09c configuration. A periodic component inside the air inlet pipe and around the central bluff body is observed, for both the inert and reactive flows. POD shows that these flow oscillations are due to single and double helical vortices, similar to Precessing Vortex Cores (PVC), that develop inside the air inlet pipe and whose axes rotate around the burner. The combustion process is found to affect the swirl flow aerodynamics. Finally, the fourth study investigates the TECFLAM configuration again, but here attention is given to the flame lift-off evident in experiments and reproduced by the LES-CMC formulation. The stabilization process and the pollutants emission of the flame are investigated in detail.

Standard IEC 61850-9-2 definuje přenos vzorkovaných měřených hodnot (sampled measured values, SMV) prostřednictvím sítě Ethernet a využití SMV získaných ze slučovacích jednotek nebo přístrojových transformátorů. Implementace IEC 61850-9-2 závisí na vlastnostech datového souboru, jakými jsou časová synchronizace, počet vzorků a časový interval. Dizertační práce je zaměřena na algoritmy chránění a analýzu vlivu standardu IEC61850-9-2LE na fyzická zařízení ochran s analogově/digitálními vstupními daty o proudu a napětí. S ohledem na narůstající míru interakce mezi fyzickými zařízeními a komunikačními prvky byl navržen test pro analýzu komunikace pro rozvodnu využívající konvenční metody (analogové vstupy) a metody digitální založené na standardu IEC 61850-9-2. Práce dále popisuje funkci slučovací jednotky využívající standard IEC61850-9-2LE. Navržená metoda definuje zdroj SMV a analyzuje přenos dat. V rámci práce byl za využití softwaru Matlab naprogramován algoritmus ochrany. Vytvořený model je schopen vyhodnotit vliv harmonického zkreslení na funkci digitálních ochran a vliv přesycení proudového transformátoru na distanční ochranu. V práci jsou zhodnoceny i možnosti zrychlení testování systémů chránění s využitím neuronové sítě. Závěrečná kapitola se zabývá aplikacemi v reálném čase, využívajícími data z rozvodny v blízkosti Vysokého učení technického v Brně. K přenosu dat z rozvodny do univerzitní laboratoře je zde využíváno SMV přenášených optickým kabelem o délce 16 km. Aplikace je vytvořena v programu Matlab a je schopna číst data z ethernetového portu, dekódovat je, převést z formátu ASCII do desítkové soustavy a poté vykreslit průběhy proudu a napětí. Mezi vlastnosti aplikace se řadí jednoduchost použití, schopnost implementace funkcí distanční ochrany, výpočet RMS hodnot proudu a napětí a harmonického zkreslení, harmonická analýza prostřednictvím rychlé Fourierovy transformace a výpočet impedance poruchové smyčky. Všechny výpočty běží v reálném čase a provedena je i citlivostní analýza modelu.