Afin de limiter les conséquences d’un hypothétique accident grave avec la fusion du coeur dans un réacteur à neutrons rapides de génération IV refroidi au sodium, la recriticité doit être évitée au sein du mélange de combustible oxyde et de structures fondus, appelé corium. Pour cela, des matériaux absorbants, tels que le carbure de bore B4C, seront utilisés dans ou près du coeur, et des matériaux diluants dans le récupérateur de corium. L’objectif de ce travail est de présélectionner des matériaux parmi ces deux types de familles et de comprendre leur comportement au contact avec le corium. Concernant le B4C, des calculs thermodynamiques et des expériences ont permis de conclure à la formation de deux phases immiscibles dans le système UO2 – B4C à haute température, une oxyde et une borure, ainsi qu’à la volatilisation d’une partie de l’élément absorbant bore. Cette séparation de phases pourra réduire l’efficacité de l’absorption neutronique au sein de la phase oxyde. Une solution à ce comportement serait d’augmenter la quantité de B4C ou d’utiliser un absorbant oxyde miscible avec le combustible. Eu2O3 ou HfO2 pourraient convenir car il a été montré qu’ils forment une solution solide avec UO2. Concernant le matériau diluant, les oxydes mixtes Al2O3 – HfO2 et Al2O3 – Eu2O3 ont été étudiés. L’interaction de ces systèmes avec UO2 étant inconnue à ce jour, les premiers points ont été recherchés sur les diagrammes ternaires correspondants. Contrairement au système Al2O3 – Eu2O3 – UO2, le mélange Al2O3 – HfO2 – UO2 présente un seul eutectique et donc un seul chemin de solidification ce qui permet de prévoir plus facilement la manière dont le corium solidifierait dans le récupérateur. / In order to limit the consequences of a hypothetical core meltdown accident in Generation IV Sodium Fast Reactors, absorber materials in or near the core, such as boron carbide B4C, and diluting materials in thecore catcher will be used to prevent recriticality within the mixture of molten oxide fuel and molten structures called corium. The aim of the PhD thesis was to select materials of both types and to understand their behaviour during their interaction with corium, from chemical and thermodynamic point of view. Concerning B4C, thermodynamic calculations and experiments agree with the formation of two immiscible phases at high temperature in the B4C – UO2 system: one oxide and one boride. This separation of phases can reduce the efficiency of the neutrons absorption inside the molten fuel contained in the oxide phase. Moreover, a volatilization of a part of the boron element can occur. According to these results, the necessary quantity of B4C to be introduced should be reconsidered for postulated severe accident sequence. Other solution could be the use of Eu2O3 or HfO2 as absorber material. These oxides form a solid solution with the oxide fuel. Concerning the diluting materials, mixed oxides Al2O3 – HfO2 and Al2O3 – Eu2O3 were preselected. These systems being completely unknown to date at high temperature in association with UO2, first points on the corresponding ternary phase diagrams were researched. Contrary to Al2O3 – Eu2O3 – UO2 system, the Al2O3 – HfO2 – UO2 mixture presents only one eutectic and thus only one solidification path which makes easier forecasting the behaviour of corium in the core catcher.

The aim of this essay was to show that the theme of how a troubled young man in a crisis who is saved by the love of a little girl is central in J.D Salinger’s novel The Catcher in the Rye, as well as in his short story “For Esmé - with Love and Squalor”. Furthermore, the argument was that there is a strong kinship between the protagonists of both stories as well as the little girl, thereby supporting the existing opinion of critics that Salinger is a writer who returns to favored themes and characters.

This thesis describes critically two famous controversial novels, one by an English author, the other by an American, in such a manner that an emotionally and intellectually secure teacher will be able to draw from these findings in order to teach either of these literary works confidently.

This thesis deals with the severe accident of the gas-cooled fast reactor GFR. At the beginning of the study there is a review of the gas-cooled fast reactor subject. Next part is focused on description of possible solutions for severe accidents with emphasis on the solution applied in the Generation III+ reactors. Chapters that deal with material and thermal balance with severe accident of GFR demonstration unit, along with the chapter which analyses features of the corium, create a basis for the conceptual design of core catcher of GFR demonstration unit, which forms the final part of this thesis.

When we build unconsciously and we build as a habit, only then we lose the essence of architecture / Master of Architecture

The information presented herein attempts to quantify the conditions surrounding concussive impacts from foul tips to the masks of catchers and umpires in baseball. Media reports of such occasions were researched on video and pitch speed data from the Pitch F/X system recorded to suggest speeds and locations at which impacts occur. To evaluate mask performance, a pneumatic-wheel, electric-motor driven pitching machine was utilized to shoot baseballs at the instrumented head of a Hybrid III dummy. Head accelerations were calculated from a 3-2-2-2 accelerometer array to allow for comparisons of linear and angular kinematics. 6 common masks (2-piece traditional-style and 1-piece hockey-style) were tested at 7 locations at 60 mph to determine the severity of each location. The center-eyebrow and chin locations were further tested at 84 mph. Speed and location data were used to evaluate a large sample of 25 masks to explore possible performance differences between manufacturer models, mask types and cage styles. The results of this study showed no significant difference between hockey-style and traditional-style mask performance. Titanium caged masks, although lighter than their steel counterparts, experienced higher linear accelerations. However, all masks experienced linear and angular accelerations well below commonly accepted injury thresholds. Yet, concussive injury has still occurred in the players and umpires that wear these masks. The work presented here can be used to help better understand these thresholds and influence the design, construction and evaluation of a new generation of masks that decrease the risk of concussions to the wearer. / Master of Science

In this thesis I aim to analyze the modern classic book The Catcher in the Rye by J.D. Salinger (1951) in an attempt to determine whether one can categorize it as a Young Adult book or not. The novel itself was published as an adult book, but my research shows that it gets both mentioned and used as an example as a novel that has influenced Young Adult literature since its publication. Furthermore, it features many of the criteria that define Young Adult literature. The aforementioned criteria are as follows: death, drugs, war, sex, alcohol, politics, suffering, gender roles, (sexual) liberation, and absent or unaware parents and adults. In addition, Young Adult literature usually uses a first-person perspective, which has led to discussions about whether the said narrator can be trusted or not. The Catcher in the Rye demonstrates many of these criteria – death, war, sex, alcohol, suffering, and parental figures and their roles. In my analysis, I focus on death, parents and the narration, specifically whether or not Holden Caulfield can be classified as an unreliable narrator. By researching the history of Young Adult literature – when it first appears as a genre and how the events come about – as well as looking into the criteria that defines the genre, I perform my analysis by doing a close reading of The Catcher in the Rye. By using my newfound facts, I discuss whether or not the novel can be categorized as Young Adult literature.

This Diploma thesis deals with the character of Holden Caulfield, the main protagonist of J.D. Salinger's novel The Catcher in the Rye, identifying him as a liminal character. It is concerned with the term liminality and inbetweennes. It focuses on evidence of his inbetweennes by means of the examples from the novel itself. It illustrates the examples of his position between childhood and adulthood by way of some of Holden's manners, behaviour and talks.

This dissertation deals with three research topics; i) the catcher bearings life prediction method, ii) the Morton effect, and iii) the two dimensional modified Reynolds equation. Firstly, catcher bearings (CB) are an essential component for rotating machine with active magnetic bearings (AMBs) suspensions. The CB's role is to protect the magnetic bearing and other close clearance component in the event of an AMB failure. The contact load, the Hertzian stress, and the sub/surface shear stress between rotor, races, and balls are calculated, using a nonlinear ball bearing model with thermal growth, during the rotor drop event. Fatigue life of the CB in terms of the number of drop occurrences prior to failure is calculated by applying the Rainflow Counting Algorithm to the sub/surface shear stress-time history. Numerical simulations including high fidelity bearing models and a Timoshenko beam finite element rotor model show that CB life is dramatically reduced when high-speed backward whirl occurs. Secondly, the theoretical models and simulation results about the synchronous thermal instability phenomenon known as Morton Effect is presented in this dissertation. A transient analysis of the rotor supported by tilting pad journal bearing is performed to obtain asymmetric temperature distribution of the journal by solving variable viscosity Reynolds equation, energy equation, heat conduction equation, and equations of motion for rotor. The tilting pad bearing is fully nonlinear model. In addition, thermal mode approach and staggered integration scheme are utilized in order to reduce computation time. The simulation results indicate that the temperature of the journal varies sinusoidally along the circumferential direction and linearly across the diameter, and the vibration envelope increased and decreased, which considers as a limit cycle that is stable oscillation of the envelope of the amplitude of synchronous vibration. Thirdly, the Reynolds equation plays an important role to predict pressure distribution in the fluid film for the fluid film bearing analysis. One of the assumptions on the Reynolds equation is that the viscosity is independent of pressure. This assumption is still valid for most fluid film bearing applications, in which the maximum pressure is less than 1 GPa. In elastohydrodynamic lubrication (EHL) which the lubricant is subjected to extremely high pressure, however, the pressure independent viscosity assumption should be reconsidered. With considering pressure-dependent viscosity, the 2D modified Reynolds equation is derived in this study. The solutions of 2D modified Reynolds equation is compared with that of the classical Reynolds equation for the plain journal bearing and ball bearing cases. The pressure distribution obtained from modified equation is slightly higher pressures than the classical Reynolds equations. / PDF file replaced 10-21-2012 at the request of the Thesis Office.

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