Thesis advisor: Richard J. Clifford / The translation of הֶבֶל (hebel) with vanitas has had a profound influence in the history of exegesis of the book of Qoheleth often characterized as the most pessimistic, skeptical, and nihilistic book in the Hebrew Bible, having as author a despondent man. This dissertation provides a corrective to the “vanity”, “meaningless”, “absurd” or negative reading of הֶבֶל in Qoheleth, by arguing that הֶבֶל has a positive value, as it expresses not the absurdity or the meaningless of life, but its fleetingness/transitoriness/brevity, whose meaning is disclosed in the opening and closing poems (1:2-11 and 12:1-8). This dissertation thus argues that the הֲבֵל הֲבָלִים הַכֹּל הָבֶל which introduces and concludes the book of Qoheleth (1:2; 12:8) is an appeal to contemplate the order, the beauty of the cosmos, through the regularity, recurrence, and cyclicality of natural phenomena. It also calls attention to the fleetingness of human experience in the world, which Qoheleth highlights in the opening and closing poems but also by the use of transient markers: יְמֵי־חַיֵּי הֶבְלוֹ ,(7:15) בִּימֵי הֶבְלִי ,(9:9), כָּל־יְמֵי חַיֵּי הֶבְלֶךָ ,(11:8) יְמֵי הַחֹשֶׁךְ (11:8) יְמֵי בְּחוּרוֹת (11:10) הַיַּלְדוּת וְהַשַּׁחֲרוּת הָבֶל (6:12), as well as אַחֲרָיו ,צֵּל and מִסְפַּר. The shortness of life and the limited duration of human achievements do not empty human life of its true meaning and value. Rather, they tell of the very nature of humans and their actions. The hebelness is from God who made things as fleeting, temporary, transient compared to his own eternity. By using the term הֶבֶל, and by introducing and concluding his book with “nature” poems, Qoheleth reminds the readers of their transience in this world with its pressing and tragic problems, as well as comforting them with the fact that evil itself is temporary in its impacts on life. They will pass away. Hence, Qoheleth’s opening and closing statement: הֲבֵל הֲבָלִים הַכֹּל הָבֶל (1:2; 12:8). / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. School of Theology and Ministry. / Discipline: Sacred Theology.

Nowadays, the Human Machine System (HMS) is considered to be a proven technology, and now plays an important role in various human activities. However, this system requires that only a human has an in-depth understanding of the machine operation, and is thus a one-way relationship. Therefore, researchers have recently developed Human Adaptive Mechatronics (HAM) to overcome this problem and balance the roles of the human and machine in any HMS. HAM is different compared to ordinary HMS in terms of its ability to adapt to changes in its surroundings and the changing skill level of humans. Nonetheless, the main problem with HAM is in quantifying the human skill level in machine manipulation as part of human recognition. Therefore, this thesis deals with a proposed formula to quantify and classify the skill of the human operator in driving a car as an example application between humans and machines. The formula is evaluated using the logical conditions and the definition of skill in HAM in terms of time and error. The skill indices are classified into five levels: Very Highly Skilled, Highly Skilled, Medium Skilled, Low Skilled and Very Low Skilled. Driving was selected because it is considered to be a complex mechanical task that involves skill, a human and a machine. However, as the safety of the human subjects when performing the required tasks in various situations must be considered, a driving simulator was used. The simulator was designed using Microsoft Visual Studio, controlled using a USB steering wheel and pedals, as was able to record the human ii path and include the desired effects on the road. Thus, two experiments involving the driving simulator were performed; 20 human subjects with a varying numbers of years experience in driving and gaming were used in the experiments. In the first experiment, the subjects were asked to drive in Expected and Guided Conditions (EGC). Five guided tracks were used to show the variety of driving skill: straight, circular, elliptical, square and triangular. The results of this experiment indicate that the tracking error is inversely proportional to the elapsed time. In second experiment, the subjects experienced Sudden Transitory Conditions (STC). Two types of unexpected situations in driving were used: tyre puncture and slippery surface. This experiment demonstrated that the tracking error is not directly proportional to the elapsed time. Both experiments also included the correlation between experience and skill. For the first time, a new skill index formula is proposed based on the logical conditions and the definition of skill in HAM.

Esta dissertação aborda o cálculo da taxa de crescimento da tensão de restabelecimento transitória (TCTRT), considerando o caso de falha na barra, durante a abertura do primeiro polo e o cálculo da tensão de restabelecimento transitória (TRT) nos primeiros instantes de tempo, incluindo o efeito da capacitância. Os principais casos possíveis de falha na barra foram analisados e os resultados demonstraram a precisão das expressões obtidas. Normalmente, o cálculo da TCTRT e da TRT é feito por meio de simulações em programas de transitórios eletromagnéticos em que há rotinas específicas para a extração dos valores destas, porém, em determinadas condições, podem ocorrer oscilações ou imprecisões numéricas. Por ser um assunto de grande interesse convém desenvolver expressões que possam esclarecer resultados duvidosos sem a necessidade de artifícios de redução do passo de integração a valores muitas vezes não factíveis. As expressões obtidas neste trabalho podem ser utilizadas não só para se obter de forma precisa e simplificada os valores da taxa de crescimento da tensão de restabelecimento transitória de um circuito real, assim como os valores da TRT nos primeiros instantes de tempo. / This study is focused on the rate of rise of transient recovery voltage (RRTRV) calculation considering the case of bus fault, during the first pole to open, and also includes the transient recovery voltage (TRV) calculation, in the first instants of time, including the capacitance effect. The main cases of bus fault have been evaluated and demonstrate that the expressions developed in this study are relevant and with good precision. Usually, the RRTRV and the TRV are calculated with the use of simulation programs, using specific routines, nevertheless, in certain conditions, there might be oscillations and numeric imprecisions which requires a mathematic expression. This topic is of great interest and it is important to have mathematical expressions that could clarify doubtful results. The expressions obtained in this study can be use in a very simples and effective mode to calculate RRTRV and the TRV in the first instants of time, considering a real life circuit.

Esta dissertação aborda o cálculo da taxa de crescimento da tensão de restabelecimento transitória (TCTRT), considerando o caso de falha na barra, durante a abertura do primeiro polo e o cálculo da tensão de restabelecimento transitória (TRT) nos primeiros instantes de tempo, incluindo o efeito da capacitância. Os principais casos possíveis de falha na barra foram analisados e os resultados demonstraram a precisão das expressões obtidas. Normalmente, o cálculo da TCTRT e da TRT é feito por meio de simulações em programas de transitórios eletromagnéticos em que há rotinas específicas para a extração dos valores destas, porém, em determinadas condições, podem ocorrer oscilações ou imprecisões numéricas. Por ser um assunto de grande interesse convém desenvolver expressões que possam esclarecer resultados duvidosos sem a necessidade de artifícios de redução do passo de integração a valores muitas vezes não factíveis. As expressões obtidas neste trabalho podem ser utilizadas não só para se obter de forma precisa e simplificada os valores da taxa de crescimento da tensão de restabelecimento transitória de um circuito real, assim como os valores da TRT nos primeiros instantes de tempo. / This study is focused on the rate of rise of transient recovery voltage (RRTRV) calculation considering the case of bus fault, during the first pole to open, and also includes the transient recovery voltage (TRV) calculation, in the first instants of time, including the capacitance effect. The main cases of bus fault have been evaluated and demonstrate that the expressions developed in this study are relevant and with good precision. Usually, the RRTRV and the TRV are calculated with the use of simulation programs, using specific routines, nevertheless, in certain conditions, there might be oscillations and numeric imprecisions which requires a mathematic expression. This topic is of great interest and it is important to have mathematical expressions that could clarify doubtful results. The expressions obtained in this study can be use in a very simples and effective mode to calculate RRTRV and the TRV in the first instants of time, considering a real life circuit.

Dans l'objectif de maîtriser le démarrage des moteurs fusées en vol balistique, il est proposé de caractériser le transitoire de remplissage des cavités d'injection des organes de combustion. L'étude s'effectue principalement sur la cavité tampon, appelée dôme. Le comburant est maintenu sous pression en amont d'une vanne dont l'ouverture contrôle son passage vers une chambre tampon qui est liée à la chambre de combustion à travers un réseau d'injecteurs. Afin d'empêcher la remontée du carburant vers la chambre tampon, un gaz balaye la chambre de l'entrée vers les injecteurs. Cette étude expérimentale consiste à décrire la structure spatio-temporelle de l'écoulement diphasique dans la cavité tampon suite à l'ouverture de la vanne en présence de l'écoulement du gaz de balayage. Il s'agit de suivre l'évolution de l'écoulement sur des temps courts (quelques centaine ms) par un ensemble de mesures (débits, pressions, distribution spatiale des phases, suivi de l'interface) sans ou avec transfert thermique aux parois de la cavité. Des fluides de substitutions sont utilisés. Pour la partie expérimentale sans transfert thermique, de l'eau et de l'air sont utilisés à la place du comburant et du gaz inerte et pour la partie non isotherme du "x" (fluorocarbone) et un gaz "y" ont été choisis. Dans le premier cas, les expériences isothermes ont mis en évidence le comportement typique des grandeurs comme la pression dans la cavité et le débit de liquide entrant ainsi que la distribution des phases en sortie d'injection, tandis qu'une analyse des résultats a montré l'importance des différentes échelles de temps qui interviennent pendant le remplissage: temps d'ouverture de la vanne, temps de recouvrement des injecteurs par le liquide et les temps de remplissage et de vidange de la cavité tampon. Dans le deuxième cas, les parois sont chauffées au-dessus de la valeur d'ébullition du liquide, pour la gamme de pression envisagée dans le dôme. Le but est de quantifier les effets d'un possible changement de phase aux parois et d'évaluer leur importance sur l'écoulement. De plus, les conséquences dues à l'échauffement du gaz de balayage constituent une partie significative du programme expérimental. Le gaz est chauffé indépendamment des parois. Un modèle théorique traitant des différents régimes d'écoulements pendant le transitoire de remplissage permet de reproduire le comportement des pressions, débit liquide et fraction volumique de gaz dans la cavité. L'ensemble de ces mesures permettent de comprendre le transitoire de remplissage de la cavité d'injection dôme et l'analyse théorique qui accompagne ces expériences doit permettre l'extrapolation des résultats obtenus en laboratoire aux conditions réelles (fluides cryogéniques sous microgravité). Elle doit aussi fournir les conditions aux limites requises pour les approches numériques développées par ailleurs ainsi que les bases de données permettant de tester ces simulations. / In order to control the ignition of rocket motors during ballistic flight, the transient flow of comburant into a reservoir or buffer cavity (dôme) and then through a grid of injectors must be carefully characterised. The liquid oxygen is held under pressure upstream of a valve which opens into the dome. The valve opening is a control parameter. To avoid any possible flow of carburant from combustion chamber back into reservoir, the latter is swept with an inert gas, thus ensuring that the pressure in the reservoir remains higher than in the combustion chamber. This experimental study has the aim of characterising the spatio-temporal structure of two-phase flow into the dome following opening of principal liquid valve. Filling the dome and forcing the liquid through the injectors has an overall time scale of some hundred milliseconds. High resolution measurements of liquid and gas flow rates, pressure, phase distribution, interface velocity and temperatures are recorded for different values of the key parameters as well as visualisations. For the experimental program with heat transfer, the comburant was replaced with "x". Much work was carried out on the effects of heat transfer from either the gas or the walls or both to the liquid entering the dome once these were above the liquid boiling point. Previous studies in the LEGI using water and air, and without heat transfer brought to light the important variations in dome pressure and liquid flow rate during the transient, while analysis of results indicated the importance of a number of time scales : value opening time, time for the liquid to cover the injectors, time to fill the dome, time to empty it. For the heat transfer experiments, the walls are heated for the pressure range chosen. The sweep gas is heated too. The aim of these experiments is to seek evidence of a phase-change at the walls or during interaction with the gas and to evaluate its importance. To carry out these experiments, specific instrumentation was used. The whole of these mesures enable us to understand the transient filling of the injection cavity. Thus, theoretical analysis have to allow extrapolations of results obteined in laboratory to real cases (cryogenic liquid under microgravity). Then, we have to give a data base to developp and validate numerical simulation.

Souvent présenté comme un «maître du temps», le Conseil constitutionnel entretient en réalité avec la temporalité une relation complexe. Le temps est en effet pour le Conseil à la fois une contrainte et une ressource. Il est d’abord une contrainte car le temps enserre le procès constitutionnel dans des délais très stricts que ce soit dans le contentieux a priori ou dans le contentieux a posteriori. Au fil des ans, le Conseil constitutionnel s’est néanmoins accommodé de cette contrainte : il a toujours réussi à juger et, qui plus est, à juger «à temps» en développant des techniques et des méthodes pour apprivoiser cette contrainte temporelle. D’un autre côté cependant, le temps peut être considéré comme une véritable ressource pour le Conseil constitutionnel. Une ressource qui s’exprime par exemple dans la construction d’une jurisprudence originale et novatrice visant à encadrer la temporalité des lois. Une ressource encore avec le développement d’une jurisprudence de la modulation des effets des décisions par laquelle le Conseil adapte ses abrogations et ses réserves d’interprétations à la diversité des situations. C’est de cette relation polarisée entre «temps-contrainte» et «temps-ressource» qu’entend rendre compte la présente étude. / Usually promoted as a “Time Master”, the Constitutional Council is in a more complexrelationship with temporality. As to the Council, Time is both a constraint and a resource. Timeis first a constraint because it ties the constitutional trial in very short delays, either that theCouncil rules a priori or a posteriori. Years passing by, the Council has nevertheless dealt withthe constraint, managing to rule “on time”, developing methods to tame the temporal constraint.On the other hand though, Time can be considered as a resource, expressing itself in theconstruction of an innovative jurisprudence that aims to frame the temporality of laws or in theupgrowth of a jurisprudence linked to the modulation of the time effects of its rulings. Thisstudy underlines such a polarized relationship between “Time-constraint” and “Time-resource”.

This doctoral project combines a performance-led practice with contextual research in order to demonstrate how arts practice can challenge historical perceptions of clay and enhance its material status. The core knowledge deduced from this research is that embodied performance transforms connectivity between artist and clay and produces a unified incarnation of both elements. Through the use of immersive research methods I gained insights which could not have been predicted - particularly that my experiential performances were a process of ‘clay becoming’ in which I ultimately became the clay. In terms of locality, the practice, comprising eight performance-led works and related documentation, focuses on the China Clay and Ball Clay of South West England. Traditionally in the arts, these materials are associated with ceramics, where through heating, clay becomes rigid and fixed. In contrast, my research investigates the textural fluidity and metamorphic potential of these clays in their raw state. The practice encompasses two interrelated groups of work; the In-breath and Out-breath. These terms are significant in three respects. Firstly they define two different modes and moments of practice. Secondly they refer to myself as a living component of these practices. Thirdly they reflect the cultural associations of clay as a metaphor for life. During the initial exploratory ‘In-breath’ phase of my practice, comprising four site-specific pieces, I engaged with clay at sites of historical relevance, building an expansive knowledge of my material. During the later ‘Out-breath’ phase, identification with site was relinquished. These works took place within neutral spaces, allowing the clay to be explored in relation to my body. The introduction of layering, where photographic elements of private clay rituals were situated within the context of a live performance, allowed a texturally dynamic and immersive experience to be created for both artist and viewer. By collecting and preserving clay traces from these live performances (e.g. foot and body prints) additional value was given to the embedded significance of the clay.

Sous la direction de SNECMA, un nouveau moteur cryotechnique pour Ariane 5 est en phase de développement. Ce moteur, VINCI, fonctionne à l'oxygène et à l'hydrogène liquides et devra être rallumable en cours de vol. Le transitoire de remplissage d'une cavité intermédiaire par laquelle transite l'oxygène liquide avant d'arriver dans la chambre de combustion s'avère être une étape critique qu'il faut s'efforcer de maîtriser. Cette cavité, appelée dôme LOX, est directement reliée à la chambre de combustion par les injecteurs à oxygène. Des outils numériques sont actuellement en cours de conception : ils permettront à terme de simuler le remplissage de cette cavité dans l'espace. Afin de valider ces outils numériques, un programme expérimental a vu le jour, impliquant SNECMA, le CNES (Centre National d'Etudes Spatiales) et le LEGI (Laboratoire des Ecoulements Géophysiques et Industriels). Il s'agit de mener à bien des expériences « simples » et reproductibles afin de disposer d'une base de données expérimentales qui servira de cas tests pour les simulations. Un banc d'essais expérimental a été progressivement mis en place et instrumenté au LEGI. Le fluide utilisé en substitution de l'oxygène liquide est de l'eau. On a choisi de respecter une similitude du nombre de Weber entre le cas « réel » et les conditions expérimentales. Ce dernier équivaut au rapport des forces d'inertie sur les forces de tension de surface. Deux campagnes d'essais ont été réalisées, dans lesquelles on s'est centré sur l'étude des aspects hydrodynamique du transitoire de remplissage : variation du débit total et des pressions au cours d'un essai, évaluation du taux de vide dans la cavité, visualisation de l'écoulement dans la cavité et en sortie des injecteurs. L'instrumentation à disposition est constituée d'un débitmètre à effet Coriolis, de capteurs de pression, d'une sonde optique, de caméras rapides et d'un laser pour l'imagerie. La première campagne d'essais a visé le remplissage de la cavité en eau seule. Le paramètre de contrôle principal était la pression génératrice de l'écoulement liquide. Dans la deuxième campagne d'essais on injecte simultanément dans la cavité un écoulement d'eau et un écoulement d'air. Cela se rapproche plus des conditions réelles du transitoire de remplissage, au cours duquel la cavité est balayée par un écoulement d'hélium. Le paramètre de contrôle supplémentaire est le débit de gaz initial. Ces campagnes ont également souligné l'importance du profil d'ouverture de la vanne de l'écoulement liquide sur le transitoire de remplissage de la cavité. Ces campagnes d'essais constituent une première étape dans la compréhension du transitoire de remplissage du dôme LOX. Elles ont permis de visualiser la forme de l'écoulement dans la cavité et en sortie des injecteurs et d'identifier certains phénomènes intervenant dans le remplissage de la cavité. En particulier, nous avons mis en évidence l'existence d'un délai de mise en place de l'écoulement par les injecteurs, qui peut être responsable d'un pic de pression dans la cavité au cours du transitoire. L'influence de la fraction gazeuse sur l'écoulement dans les injecteurs a été soulignée mais reste à quantifier de façon précise. La prochaine étape de l'étude concerne les aspects énergétiques du transitoire de remplissage, notamment les transferts thermiques ayant lieu, dans la réalité, entre l'hélium, l'oxygène et les parois du dôme LOX. / Under the supervision of SNECMA, a new cryotechnic engine is being developed for Ariane 5. This engine, named VINCI, uses liquid oxygen and liquid hydrogen as propellant. It must be re-ignitable in flight. The filling transitory phase of an intermediate tank where the liquid oxygen passes through before entering the combustion chamber, has proved to be a very important stage that must be handled. This tank, called LOX dome, is directly linked to the combustion chamber through the oxygen injectors. Numerical tools are currently under development. They will allow to simulate the filling of this tank in the space. In order to validate those numerical tools, an experimental program has been launched. It involves SNECMA, the CNES (Centre National d'Etudes Spatiales : National Centre for Spatial Studies) and the LEGI (Laboratoire des Ecoulements Géophysiques et Industriels : Laboratory of Geophysical and Industrial Flows). Simple and repeatable experiments must be run. They will allow to gather experimental data that will further be used as test cases for the simulations. A test bench has been brought into service step by step at the LEGI, as well as scientific instruments. Water is used in place of liquid oxygen. A similarity of flows based on the Weber number has been chosen between the real case and the experiment. The Weber number measures the relative importance of the fluid inertia compared to its surface tension. Two experimental campaigns have been realized, that have focused on the dynamic aspects of the filling transitory phase : variations of the total flow and of the pressures measured during an experiment, evaluation of the void fraction in the tank, flow visualization in the tank and at the outlet of the injectors. The scientific instrumentation used is made of a Coriolis flow-meter, pressure probes, an optical probe, and high speed cameras with a laser for the flow visualization. The first experimental campaign has studied the tank filling with water only. The main control parameter is the reference pressure of the liquid flow. In the second campaign, both liquid and air flows are simultaneously injected in the tank. It aims at reproducing the real conditions of the filling transitory phase, where helium is injected in the tank with the liquid oxygen. The additional control parameter is the initial gas flow. Those campaigns have shown as well the importance of the valve opening that controls the liquid flow. Those campaigns are a first step in the understanding of the filling transitory phase of the LOX dome. They have permitted to visualize the flow in the tank and at the outlet of the injectors and to point out some important phenomena occurring during the tank filling. In particular, they have highlighted the existence of a delay before the flow can develop through the injectors. This delay can be responsible for a pressure peak in the tank during the transitory phase. The influence of the gas fraction on the flow through the injectors has been underlined as well but still must be accurately quantified. The next step of the study concerns the energetics of the filling transitory phase, especially the thermal transfers that occur between the helium, the oxygen and the walls of the tank.

Submitted by Fernando Luiz Cordeiro (fernandolpcordeiro@gmail.com) on 2018-06-22T20:12:54Z No. of bitstreams: 1 SDFDecomposition_finalv.pdf: 845158 bytes, checksum: 5ceb09364caa557c2198d20e41ee5522 (MD5) / Approved for entry into archive by GILSON ROCHA MIRANDA (gilson.miranda@fgv.br) on 2018-06-29T19:55:51Z (GMT) No. of bitstreams: 1 SDFDecomposition_finalv.pdf: 845158 bytes, checksum: 5ceb09364caa557c2198d20e41ee5522 (MD5) / Made available in DSpace on 2018-07-02T18:21:34Z (GMT). No. of bitstreams: 1 SDFDecomposition_finalv.pdf: 845158 bytes, checksum: 5ceb09364caa557c2198d20e41ee5522 (MD5) Previous issue date: 2018 / In this work, we use the framework developed by Christensen (2017) and Hansen and Scheinkman (2009) to study the long-term interest rates in the US and Brazil. In our first set of results, we assess Christensen (2017) estimator using Monte Carlo simulations in order to evaluate the estimator performance in the rare disasters and habit formation asset pricing models. Generally, the estimation quality is not uniform and, in some cases, requires a large sample size to attain reasonable results. Next, we apply the nonparametric estimation to US and Brazilian data and estimate how the yield of a long-term zero-coupon bond responds to the initial state of the economy. Using a flexible specification for the state process leads to an interesting non-linear response of the yield to changes in the initial state. We find that the Brazilian long-term interest rate is about 5.3% per year.

No description available.