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Modelling the transition from channel-veins to PSBs in the early stage of fatigue testsZhu, Yichao January 2012 (has links)
Dislocation channel-veins and persistent slip bands (PSBs) are characteristic dislocation configurations that are of interest to both industry and academia. However, existing mathematical models are not adequate to describe the mechanism of the transition between these two states. In this thesis, a series of models are proposed to give a quantitative description to such a transition. The full problem has been considered from two angles. Firstly, the general motion and instabilities of arbitrary curved dislocations have been studied both analytically and numerically. Then the law of motion and local expansions are used to track the shapes of screw segments moving through channels, which are believed to induce dislocation multiplication by cross-slip. The second approach has been to investigate the collective behavior of a large number of dislocations, both geometrically necessary and otherwise. The traditional method of multiple scales does not apply well to describe the pile-up of two arrays of dislocations of opposite signs on a pair of neighbouring glide planes in two dimensional space. Certain quantities have to be more accurately defined under the multiple-scale coordinates to capture the much more localised resultant stress caused by these dislocation pairs. Through detailed calculations, one-dimensional dipoles can be homogenised to obtain some insightful results both on a local scale where the dipole pattern is the key diagnostic and on a macroscopic scale on which density variations are of most interest. Equilibria of dislocation dipoles in a two-dimensional regular lattice have been also studied. Some natural transitions between different patterns can be found as a result of geometrical instabilities.
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A Study of Physical, Mental and Musical Characteristics of Selected Band MembersWagner, Hilmar Ernest 06 1900 (has links)
The study was concerned with physical, mental and musical characteristics of selected band members. Certain purposes of the study were defined. They were 1. To determine if physical, mental and musical differences existed between sections of the high school band. 2. To determine if these differences were existent at three grade-level groupings of high school and college band members.
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A Rehearsal Method for Presenting Historical and Theoretical Aspects of Selected Works for Concert BandHansuld, Arthur Marr, 1942- 08 1900 (has links)
The purpose of this study was to design a rehearsal method for presenting the historical and theoretical aspects of selected works for concert band. 1. 'What systematic approach can be designed for studying the historical aspects of a musical work? 2. What systematic approach can be designed for studying the theoretical aspects of a musical work? 3. What compositions can be used to demonstrate historical and theoretical elements? 4. What rehearsal method can be devised by applying the systematic approaches for studying historical and theoretical aspects to the selected works?
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The Vacuum Ultraviolet Spectra of Cyclohexane, Cyclohexene, 1,4-Cyclohexadiene, Isotetralin, and Several Methyl Substituted AnalogsTidwell, Edgar Rhea 12 1900 (has links)
A paucity of literature exists on the Independent System analysis of adjacent, parallel transition dipoles. Applying this theory and certain spectral information semiemperical calculations were made to predict absorption profiles and band intensities. To aid in the assignment of the 7*+7 absorption bands it was necessary to obtain the vacuum ultraviolet spectra of cyclohexane and cyclohexene. Because the spectra of these molecules contained sharp, atomic-like absorption bands a Rydberg series could be fitted to certain absorptions, thus the determination of their ionization potentials. Using Independent System analysis profiles and intensities of 7*+q-- absorption bands ins 'several methyl substituted 1,4- cyclohexadienes and isotetralin were predicted where general agreement was found with observed experimental spectra.
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Guidance Factors in the Selection of Students for the Study of Instrumental Music in the Public Schools of Tulsa, OklahomaHayes, Kenneth, 1908- 08 1900 (has links)
Instrumental music classes in the public schools of Tulsa, Oklahoma, have experienced a phenomenal growth during the past twenty years. Prior to this period, opportunity for instrumental music expression was limited to the high school band and orchestra,which rehearsed outside of school hours. No instruction other than this was provided and the student who wished to play in the school band or orchestra studied first from private instructors. In this study the investigator has examined a great many devices for measuring capacities and aptitudes which are known to the profession. He has attempted to evaluate these procedures in the light of sound educational philosophy. He has set forth a plan which he believes will materially improve the instrumental program through discovering unsuspected musical capacity and through sound guidance in the selection of suitable instruments.
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A Proposed Music Theory Text Book for Instrumental Students of High Schools of 250-750 Enrollment, Who Have a Limited Amount of Public School MusicMcMath, Robert Carroll, 1919-1996 06 1900 (has links)
It is the author's purpose, after a thorough study of published theory books, to present a proposed textbook in music theory to meet the needs of the average high school student.
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A Critical Compilation of Graded Band Material at High School LevelSonnenburg, Eldon M. (Eldon Malcome) 08 1900 (has links)
The instrumental composition of the band is an outgrowth of utilitarian improvisation. The well-developed percussion section, and the voluminous reed and brass sections are a carry-over from the Military, where the emphasis was on functional beating of time for marching. Mobility and volume sufficient for the accompaniment of troop movements were also necessary. Until recent times, the band existed only for functional matters, never as an independent and self-justifying medium with its purpose being a musical organization.
Through the growth of military, professional, and school bands, the band of today has developed into a musical organization in its own right, which can perform almost anything in the technical range of composition.
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Quantile-based methods for prediction, risk measurement and inferenceAlly, Abdallah K. January 2010 (has links)
The focus of this thesis is on the employment of theoretical and practical quantile methods in addressing prediction, risk measurement and inference problems. From a prediction perspective, a problem of creating model-free prediction intervals for a future unobserved value of a random variable drawn from a sample distribution is considered. With the objective of reducing prediction coverage error, two common distribution transformation methods based on the normal and exponential distributions are presented and they are theoretically demonstrated to attain exact and error-free prediction intervals respectively. The second problem studied is that of estimation of expected shortfall via kernel smoothing. The goal here is to introduce methods that will reduce the estimation bias of expected shortfall. To this end, several one-step bias correction expected shortfall estimators are presented and investigated via simulation studies and compared with one-step estimators. The third problem is that of constructing simultaneous confidence bands for quantile regression functions when the predictor variables are constrained within a region is considered. In this context, a method is introduced that makes use of the asymmetric Laplace errors in conjunction with a simulation based algorithm to create confidence bands for quantile and interquantile regression functions. Furthermore, the simulation approach is extended to an ordinary least square framework to build simultaneous bands for quantiles functions of the classical regression model when the model errors are normally distributed and when this assumption is not fulfilled. Finally, attention is directed towards the construction of prediction intervals for realised volatility exploiting an alternative volatility estimator based on the difference of two extreme quantiles. The proposed approach makes use of AR-GARCH procedure in order to model time series of intraday quantiles and forecast intraday returns predictive distribution. Moreover, two simple adaptations of an existing model are also presented.
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Spectroscopie de plasma induit par laser appliquée à la détection de résidus d'explosifsMothe, Emilien 15 December 2011 (has links)
La menace d’attaques terroristes reste omniprésente dans de nombreux lieux à forte fréquentation. Une technique capable de détecter les substances explosives est donc nécessaire pour traiter au mieux cette menace. Initié par le Ministère de la Défense et la Direction générale de l’Armement, le projet REI ExploLIBS a pour but d’étudier le potentiel de la spectroscopie de plasma induit par laser à détecter les résidus d’explosifs. Des études expérimentales et théoriques sont menées par Bertin Technologies en collaboration avec le laboratoire LP3 – UMR 6182. L’ablation de polymères sous différentes atmosphères a permis de caractériser l’évolution spatio-temporelle de l’émission des molécules CN et C2. Le rayon d’émission, la température et la décroissance de l’intensité sont reliés au processus de formation des molécules. L’analyse complémentaire par le calcul de la composition du plasma en équilibre thermodynamique local permet de mettre en évidence la présence de molécules en fortes concentrations dans le plasma difficiles à visualiser en spectroscopie optique. Ces études ont abouti au développement d’une sonde portable dédiée à la détection des explosifs. Le taux de détection est évalué à plus de 90% et le taux de faux positif inférieur à 5%. La limite actuelle de sensibilité est estimée à 55 µg.cm-2. / The threat of terrorist attacks remains omnipresent in many high traffic sites. A technique capable of detecting explosives is needed to best address this threat. Initiated by the Ministère de la Défense and the Direction Générale de l’Armement, the project REI ExploLIBS aims to explore the potential of laser-induced breakdown spectroscopy to detect explosive residue. Experimental and theoretical studies are carried out by Bertin Technologies in collaboration with the LP3 laboratory – UMR 6182. The ablation of polymers under different atmospheres permits to characterize the spatial and temporal evolution of the emission of the CN and the C2 molecules. The radius of emission, the temperature and the decrease of the intensity are related to the formation process of the molecules. The additional analysis by the calculation of the composition of the plasma in local thermodynamic equilibrium reveals the presence of molecules in high concentrations in the plasma that are difficult to visualise in optical spectroscopy. These studies led to the development of a portable sensor dedicated to the detection of explosives. The detection rate is estimated at over 90% and the false positive rate below 5%. The current sensitivity limit is estimated at 55 µg.cm-2.
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Construção de um sistema para ressonância paramagnética eletrônica em baixa freqüência: banda L e banda S / Developing of microwave bridge for electron paramagnetic resonance spectroscopy at L and S bandsSartori, Jose Carlos 22 January 1991 (has links)
Neste trabalho são apresentados o desenvolvimento e construção de um sistema de microondas para espectroscopia paramagnética eletrônica em baixa freqüência (bandas L e S). Basicamente o sistema é composto de um oscilador que opera na faixa de 1,0 a 2,0 GHZ, uma cavidade do tipo Bridged Loop-Gap, acopladores direcionais, circuladores, atenuadores, detetor, sistemas de controle automático de freqüência CAF e pré-amplificador. Todo o arranjo compõe uma ponte de microondas que é acoplada à unidade de processamento e registro do espectrômetro VARIAN (E-109) do Laboratório do grupo de biofísica do IFQSC. No sistema apresentado os estágios de amplificação de baixo ruído, circuito de CAF, pré-amplificador e sistema ressonante foram desenvolvidos e implantados localmente. A conveniência em se utilizar um espectrômetro de RPE em baixa freqüência é permitir o estudo de amostras que apresentam características espectrais vindas das interações hiperfinas e superhiperfinas parcialmente resolvidas em freqüências mais altas. Também é possível obter-se parâmetros de energia de campo zero de sistemas de spin com S > 1 se o sistema puder ser tratado por métodos aproximativos em banda X. Um exemplo utilizando o íon Cr3+ no garnet CGGG é mostrado neste trabalho / In this work a microwave bridge for electron paramagnetic resonance spectroscopy hás been developed. The system is suitable for operation at low frequency, basically L and S-band. It is composed of an oscilator with a 1.0 to 2.0 GHz bandwith, a Bridged loop-gap resonator, directional couplers, circulators, attenuators, reverse diode detector, AFC sub-system and a pré-amplifier. All these modules are assembled to a constitute a microwave bridge, which is coupled to the processing and register unit of the VARIAN E-109 EPR spectometer of the Biophysics Laboratory at IFQSC. The low-noise amplifier, AFC sub-system, pre-amplifier and the Bridged Loop-Gap resonator have been entirely developed in this work. The advantage in the use of the low frequency EPR spectometer is that it allows the study of samples which present paramagnetics structures that are obscured by g-strain at high frequency (X, Q band). These structures come out from hiperfine and superhiperfine poorly resolved in the high frequency range that could be conventienly resolved at low frequency. It is also possible, to obtain the zero field splitting parameters in spin systems with S > 1, if a perturbative approximation is useful, comparing the spectre in X and L band. One example of this new approad using Cr3+ as impurity in the CGGG garnet is presented.
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