Dissertations / Theses on the topic 'Rotating cone'
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1
Tham, K. M. "Flow and heat transfer in a H.P. compressor drive cone cavity." Thesis, University of Sussex, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270356.
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Chen, Shufei. "Markerless Lung Tumor Trajectory Estimation from Rotating Cone Beam Computed Tomography Projections." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4439.
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Respiration introduces large tumor motion in the thoracic region which influences treatment outcome for lung cancer patients. Tumor motion management techniques require characterization of temporal tumor motions because tumor motion varies patient to patient, day to day and cycle to cycle. This work develops a markerless algorithm to estimate 3 dimensional (3D) lung-tumor trajectories on free breathing cone beam computed tomography (CBCT) projections, which are 2 dimensional (2D) sequential images rotating about an axis and are used to reconstruct 3D CBCT images.
A gold standard tumor trajectory is required to guide the algorithm development and estimate the tumor detection accuracy for markerless tracking algorithms. However, a sufficient strategy to validate markerless tracking algorithms is lacking. A validation framework is developed based on fiducial markers. Markers are segmented and marker trajectories are xiv obtained. The displacement of the tumor to the marker is calculated and added to the segmented marker trajectory to generate reference tumor trajectory. Markerless tumor trajectory estimation (MLTM) algorithm is developed and improved to acquire tumor trajectory with clinical acceptable accuracy for locally advanced lung tumors. The development is separate into two parts. The first part considers none tumor deformation. It investigates shape and appearance of the template, moreover, a constraint method is introduced to narrow down the template matching searching region for more precise matching results. The second part is to accommodate tumor deformation near the end of the treatment. The accuracy of MLTM is calculated and compared against 4D CBCT, which is the current standard of care.
In summary, a validation framework based on fiducial markers is successfully built. MLTM is successfully developed with or without the consideration of tumor deformation with promising accuracy. MLTM outperforms 4D CBCT in temporal tumor trajectory estimation.
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May, Nicholas Edward. "Prediction of the flow and heat transfer between a rotating and a stationary cone." Thesis, University of Plymouth, 1990. http://hdl.handle.net/10026.1/1276.
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This thesis is concerned with the development of a theoretical method for predicting the turbulent flow and heat transfer in the cavity between a rotating and a stationary cone. The motivation for the work stems from the need, in the design process for the gas turbine aero-engine, for a fast and reliable predictive method for such flows. The method developed here is the integral method, which reduces the governing partial differential equations to ordinary differential equations. A number of solution methods for these equations are described, and the optimum in terms of speed and accuracy is indicated. Predicted moment coefficients compare well with experimental data. For half-cone angles greater than approximately 60° but poorly for half cone angle less than approximately 45°. The poor agreement for small cone angles is thought to be due to the presence of Taylor-type vortices, which cannot be incorporated into the integral method. Heat transfer is incorporated into the method using the Reynolds analogy. Due to the lack of experimental data, heat transfer predictions are compared with those from a finite difference program and show encouraging agreement. A computer program which solves the full Reynolds-averaged Navier-Stokes and energy equations in steady and axisymmetric form, using a finite-difference method is modified for use in the conical geometry. Comparison of the predicted moment coefficients with experimental data shows no marked improvement over the integral method. Examination of the secondary flow predicted by the program shows it to be similar to that of the integral method. The failure of the program to predict Taylor-type vortices may be attributed to the fact that they are non-axisymmetric and/or unsteady. The assumptions underlying the Integral method are investigated via the finite difference program and it is concluded that they are valid for half cone angles as small as 15°. Based on the results of the finite difference program, the Integral method is modified to allow for a rectangular outer shroud, and a new model for the stator is described. It is concluded that both the integral method and the finite difference program can be used safely in rotor-stator systems where the half cone angle is greater than about 60°.
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Telford, Rosie. "Three dimensional simulations of rotating core collapse supernovae." Thesis, University of Leicester, 2005. http://hdl.handle.net/2381/30693.
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A core collapse supernova is the dramatic death of a massive star by core implosion and subsequent explosion. Massive stars are known to rotate appreciably, yet the vast majority of supernova simulations over the years have not included rotation or its effects.;It is thought that moderate stellar rotation could assist the supernova explosion by lowering the effective gravitational potential in the core. More rapid rotation could give rise to jets and/or bipolar explosions. At the most extreme rotation rates it is thought that gamma ray bursts (GRB) are produced. These bursts may be delayed or revived at late times as a result of the collapsing core becoming rotationally unstable and fragmenting.;In this thesis the effects of rotation on core collapse are studied. Sophisticated progenitor models with rotation rates of up to a significant fraction of Keplerian are used as the starting points for three dimensional simulations. The computational method of Smoothed Particle Hydrodynamics is used to follow the collapse until core "bounce", the point at which the collapse is halted.;It is shown that, before bounce, no instabilities occur even for the most rapid rotators. The maximum value obtained for the ratio of rotational to gravitational binding energy is around 0.13, just below the limit of 0.14 required for instability on a secular timescale. However, the more rapidly rotating models obtain interesting structures as they collapse. In these models the density distribution remains centrally peaked but is surrounded by a torus of centrifugally supported material, consistent with the collapsar model of GRB.;The gravitational wave signals emitted in collapse are also calculated. It is found that these are strongest for the slowly rotating models, in which the collapse is not slowed significantly. A supernova of this type in the Virgo galaxy cluster would be beyond the range of the current generation of gravitational wave detectors.
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Coffey, Paul Anthony. "The influence of topography upon rotating magnetoconvection." Thesis, University of Newcastle Upon Tyne, 1996. http://hdl.handle.net/10443/1572.
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Aspects of thermal convection in the Earth's fluid core in the presence of a strong azimuthal magnetic field may be understood by considering a horizontal plane layer, rotating about the vertical z axis, with gravity acting downwards and containing an applied magnetic field aligned in the y (azimuthal) direction. Since the OMB is not smooth, the effects of adding bumps (with axes perpendicular to the applied magnetic field) to the top boundary of the layer are investigated in the magnetogeostrophic limit. The arbitrary geostrophic flow that arises under this limit is evaluated using a modified Taylor constraint. The bumps distort the isotherms so that they are not aligned with equipotential surfaces, leading to an imperfect configuration. This means that a hydrostatic balance is not possible, and motion ensues. This motion takes the form of a steady transverse convection roll, with axis parallel to the bumps. The roll exists for all values of the Rayleigh number, except that value for which the corresponding homogeneous problem in the standard plane layer has a solution. The roll obeys Taylor's constraint, and has no associated geostrophic flow. The stability of this roll to perturbation by oblique rolls (which are preferred for 0(1) values of the Elsasser number) is considered. It is found that the most unstable linear mode consists of a pair of these oblique rolls, aligned so that no geostrophic flow is accelerated by their interaction with the basic state. Hence, the stability results obtained here are identical to those found by perturbing the hydrostatic conduction solution with oblique rolls in the standard layer. Finally, the nonlinear evolution through the Ekman regime of these linear instabilities is considered. It is found that the nonlinear convection behaves similarly to mean field dynamo models which incorporate a geostrophic nonlinearity. Various types of Ekman solution are found, and evolution to Taylor states is observed.
6
Fraser, Samuel Carroll. "Prediction of thin films obliquely deposited in rotating recessed cones." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/9340.
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Chatzopoulos, E., Sean M. Couch, W. David Arnett, and F. X. Timmes. "CONVECTIVE PROPERTIES OF ROTATING TWO-DIMENSIONAL CORE-COLLAPSE SUPERNOVA PROGENITORS." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/621238.
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We explore the effects of rotation on convective carbon, oxygen, and silicon shell burning during the late stages of evolution in a 20 M-circle dot star. Using the Modules for Experiments in Stellar Astrophysics we construct one-dimensional (1D) stellar models both with no rotation and with an initial rigid rotation of 50% of critical. At different points during the evolution, we map the 1D models into 2D and follow the multidimensional evolution using the FLASH compressible hydrodynamics code for many convective turnover times until a quasi-steady state is reached. We characterize the strength and scale of convective motions via decomposition of the momentum density into vector spherical harmonics. We find that rotation influences the total power in solenoidal modes, with a slightly larger impact for carbon and oxygen shell burning than for silicon shell burning. Including rotation in 1D stellar evolution models alters the structure of the star in a manner that has a significant impact on the character of multidimensional convection. Adding modest amounts of rotation to a stellar model that ignores rotation during the evolutionary stage, however, has little impact on the character of the resulting convection. Since the spatial scale and strength of convection present at the point of core collapse directly influence the supernova mechanism, our results suggest that rotation could play an important role in setting the stage for massive stellar explosions.
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Gaillard, Thomas. "Étude numérique du fonctionnement d’un moteur à détonation rotative." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLC011/document.
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Cette thèse s’inscrit dans le domaine de la simulation numérique appliquée à la propulsion. Le moteur à détonation rotative (RDE) fait partie des candidats susceptibles de remplacer nos actuels moyens de propulsion grâce à l’augmentation du rendement thermodynamique du moteur. Pour conserver l’avantage de la détonation, l’injecteur doit fournir un mélange dont la qualité doit être la meilleure possible tout en limitant les pertes de pression totale. La présente étude porte sur le développement et l’optimisation numérique d’un injecteur adapté au fonctionnement d’un RDE. L’injection d’hydrogène et d’oxygène gazeux en rapport stoechiométrique est considérée pour une utilisation en propulsion fusée. Le premier objectif est de proposer un concept réaliste d’injecteur permettant de maximiser le mélange des ergols. Le second objectif est de réaliser des études du mélange dans la chambre par des simulations LES (Large Eddy Simulation). Le troisième objectif est de simuler la propagation d’une détonation rotative (RD) alimentée par différents injecteurs en régimes prémélangé et séparé. Deux éléments d’injection sont mis en concurrence. Le premier utilise le principe de jets semi-impactants de H2 et de O2. Le deuxième représente une configuration améliorée. Les simulations de RD avec les deux injecteurs donnent des résultats similaires lorsque l’injection est prémélangée. La part du mélange injecté perdu par déflagration est de 30% et la vitesse de propagation de la RD est proche de la vitesse théorique CJ. Pour les injections séparées de H2 et O2, l’injecteur amélioré permet de conserver un bon niveau de mélange dans la chambre, contrairement à l’injecteur à semi-impact qui produit une forte stratification des ergols dans la chambre. En conséquence, la vitesse de propagation de la RD est proche de la vitesse CJ avec l’injecteur amélioré et limitée à 80% de la vitesse CJ avec l’injecteur à semi-impactThis thesis pertains to the domain of numerical simulation for propulsion applications. The rotating detonation engine (RDE) appears to be a good candidate to replace our current means of propulsion thanks to the increase of the thermodynamic efficiency. To preserve the advantage given by the detonation mode, the injector must provide the best possible mixing of the propellants together with acceptable total pressure losses. This numerical study deals with developing and optimizing an injector adapted to the operation of a RDE. Injection of gaseous H2 and O2 at stoichiometric ratio is considered to be suitable for rocket propulsion application. The first goal is to propose an efficient injector design so that the mixing between the propellants is maximized. The second goal is to perform simulations of the mixing process in the chamber by LES (Large Eddy Simulation) computations. The third goal consists in computing the propagation of a rotating detonation (RD) fed by different injectors in premixed and separate regimes. This study allows the comparison of two injection elements. The first one uses the principle of semi-impinging jets of H2 and O2. The second one represents an improved configuration. RD simulations with both injectors provide similar results when premixed injection is considered. The part of the injected mixture that burns by deflagration is 30% and the detonation velocity remains close the theoretical CJ velocity. In the regime of separate injection of H2 and O2, the improved injector enables to keep a high mixing efficiency in the chamber whereas the semi-impingement injector produces a strong stratification of the propellants in the chamber. As a consequence, the detonation velocity is close to the CJ velocity with the improved injector and limited to 80% of the CJ velocity with the semi-impingement injector
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Seyed-Mahmoud, Behnam. "Elliptical instability in rotating ellipsoidal fluid shells applications to the earth's fluid core /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0004/NQ43451.pdf.
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Bergman, Michael I. (Michael Ira). "Magnetohydrodynamics of the Earth's core : 1) steady, rotating magnetoconvection 2) magnetic Rossby waves." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/51501.
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Towers, Paul David. "The stability and transition of the compressible boundary-layer flow over broad rotating cones." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/28219.
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The subject of fluid flows over axisymmetric bodies has increased in recent times, as they can be used to model flows over a swept wing, spinning projectiles and aeroengines amongst other things. A better mathematical understanding of the transition from laminar to turbulent flow within the boundary layer could lead to an improvement in the design of such applications. We consider a compressible fluid flow over a rotating cone, defined by half-angle ψ. The mean flow boundary-layer equations are derived and we conduct a high Reynolds number asymptotic linear stability analysis. The flow is susceptible to instabilities caused by inviscid crossflow modes (type I ) and modes caused by a viscous-Coriolis balance force (type II ). Both are considered, along with the effects of changes in the cone half-angle, the magnitude of the local Mach number and the temperature at the cone wall. A surface suction along the cone wall is also analysed.
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PONSONNAILLE, OLIVIER. "Ecoulement permanent d'un fluide incompressible entre deux cones solidaires en rotation." Paris 11, 1997. http://www.theses.fr/1997PA112345.
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L'ecoulement entre deux cones a ete largement considere pour une meilleure comprehension des performances des centifugeuses du type a assiettes utilisees dans differents domaines industriels et pharmaceutiques. La plupart des travaux theoriques ont cherche les solutions de l'ecoulement entre deux cones en rotation soit en linearisant les equations de navier stokes soit en effectuant des approximations basees sur l'analyse des differents nombres sans dimension caracterisant l'ecoulement (tels que les nombres de reynolds, taylor, rossby et ekman). Dans cette etude, les equations completes de navier stokes sont considerees pour un tel ecoulement et les solutions sont trouvees en postulant que les composantes du champ de vitesse et la pression inconnues s'ecrivent sous la forme d'un developpement en serie de fonctions. Les trois composantes du champ de vitesse ainsi que la pression ont ete determinees. Des experiences ont ete conduites dans le but de valider les solutions analytiques. Les mesures des composantes axiale et tangentielle de vitesse par anemometrie laser a effet doppler sont en tres bon accord avec les resultats theoriques correspondants.
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Isse, Takehi. "Regional differences of the anisotropy and differential rotation of the inner core." 京都大学 (Kyoto University), 2001. http://hdl.handle.net/2433/150377.
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Fleming, Devinna Danielle, and Devinna Danielle Fleming. "Faraday Rotation in Magnetic Ionic Liquids for Liquid Core Optical In-Line Isolator Applications." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/623082.
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A suspended ionic solution of 1-butyl-3-methylimidazolium iron tetrachloride [BMIM][FeCl4] provides a novel medium for achieving Faraday rotation under small magnetic fields at pump wavelengths of 980nm. As verified with spectrophotometry, transmission at telecommunication wavelengths makes the solution applicable across multiple applications. A cryostation was used to measure the sample up to a 340K and under field at 600mT, the ionic sample shows the necessary temperature stability and enables compact formats suitable for potential industrial applications. With a rotation of linearly polarized light of 0.04° over a 450um path length, a full 45° rotation requires only a 50.6cm path length and with only a 0.000175°/K temperature dependence. The observation of polarization effects in real time using lock-in amplifiers, and a photo-elastic modulator demonstrates the scalability, responsiveness, and stability of the ionic liquids for photonic integration. The test set up provides a convenient way to expand the research on ionic liquid Faraday rotation materials and other Faraday liquids ideally leading to a compact in-line isolator solution.
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Разаві, Сейед Фаршад. "Гідродинамічні особливості потока аномально-в'язких рідин у конічної поверхні ковзання." Doctoral thesis, Київ, 2019. https://ela.kpi.ua/handle/123456789/29180.
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Дисертаційна робота присвячена дослідженню впливу гідродинаміки в'язких і
аномально в'язких мастильних матеріалів у конічних зазорах зі змінною величиною
конусності. Подібні завдання є актуальними при дослідженні конічних опорних
підшипників, які знайшли широке застосування в гідротурбінобудуванні та інших
сферах гідромашинобудування. Одним з важливих питань у даному напрямку є
визначення крутного моменту сил в'язкого тертя в щілинних конічних зазорах.
В роботі, проведено критичний аналіз досліджень, присвячених даній темі, зроблено
висновок про недостатність досліджень і поставлена задача, розв’язання якої
пропонується в даній роботі. На підставі досліджень інших авторів виведені основні
критерії подібності, які можуть охарактеризувати цей процес поведінки рідини в
зазорі, де одна з поверхонь (внутрішня) може обертатися навколо своєї осі. Проведено
фізичне і математичне моделювання поведінки рідини в конічних підшипниках. На
підставі експериментальних досліджень були отримані функціональні залежності
визначення крутного моменту як функції частоти обертання внутрішнього конуса,
в'язкості змащує рідини, ширини щілинного зазору між конічними поверхнями.
Отримані результати були зіставлені з аналогічними даними для циліндричних
щілинних зазорів (циліндричних підшипників ковзання). Представлені рекомендації по
розрахунку основних характеристик потоку. Проведення математичне моделювання
дало можливість оцінити ступінь відмінності між результатами експерименту і теорії,
пояснити розбіжності в результатах. Одним з найважливіших моментів дослідження є
результат, пов'язаний з поведінкою аномально-в'язких рідин (деякі з мастильних
матеріалів за своєю поведінкою близькі до рідин, поведінка яких можна описати
рівнянням Освальда де Віля). Проведене моделювання процесів, що розглядаються в
конічних щілинних зазорах, дало можливість забезпечити раціональний вибір
змащувальних матеріалів для зниження моменту тертя (сил тертя) в конічних зазорах.
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Simard, Guy. "La modélisation de la combustion dans un four de calcination de coke de pétrole /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1992. http://theses.uqac.ca.
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Reshef, Aymeric. "Dual-rotation C-arm cone-beam tomographic acquisition and reconstruction frameworks for low-contrast detection in brain soft-tissue imaging." Electronic Thesis or Diss., Paris, ENST, 2018. http://www.theses.fr/2018ENST0044.
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L’arceau interventionnel est un système d’imagerie rayons X temps réel. Il dispose d’une option tomographique qui, grâce à une rotation de l’arceau autour du patient, permet d’acquérir des images en coupes dont la résolution en contraste est plus faible que celle des tomodensitomètres diagnostiques, rendant l’information clinique des tissus mous du cerveau inexploitable. Nous proposons un nouveau mode d’acquisition et de reconstruction tomographiques sur arceau interventionnel pour l’amélioration de la détection des faibles contrastes en imagerie interventionnelle des tissus mous de la tête. Afin d’émuler un filtre « bow-tie » (en nœud papillon), une double acquisition est envisagée. Les spécificités de la double acquisition imposent la conception d’un algorithme de reconstruction itérative dédié, incluant le filtre rampe dans l’énergie de minimisation. En bifurquant des approches par rétro-projection filtrée vers celles par filtration des rétro-projections, une méthode de reconstruction directe, alternative à la précédente, est proposée pour les acquisitions doubles. Pour une acquisition simple, la méthode est assurée de faire aussi bien que l’algorithme de rétro-projection filtrée quel que soit l’échantillonnage angulaire en géométrie planaire, et offre une approximation alternative à l’algorithme de Feldkamp-Davis-Kress en géométrie conique. Nous montrons qu’avec peu ou pas de modifications aux schémas précédents, les deux méthodes de reconstruction (itérative et directe) s’adaptent bien à la reconstruction de régions d’intérêt, à laquelle l’acquisition double reste étroitement liée à travers son acquisition tronquéeInterventional C-arm systems are real-time X-ray imaging systems, that can perform tomographic acquisitions by rotating the C-arm around the patient ; however, C-arm cone-beam computed tomography (CBCT) achieves a lower contrast resolution than diagnostic CT, which is necessary in order to benefit from the clinical information of soft tissues in the brain. We propose a new C-arm CBCT acquisition and reconstruction framework to increase low-contrast detection in brain soft-tissue imaging. In order to emulate a bow-tie filter, a dualrotation acquisition is proposed. To account for all the specificities of the dual-rotation acquisition, a dedicated iterative reconstruction algorithm is designed, that includes the ramp filter in the cost function. By switching from filtered backprojection (FBP) to backprojection-filtration (BPF) reconstruction methods, we propose an alternative, direct reconstruction method for dual-rotation acquisitions. For single-rotation acquisitions, the method ensures to perform as good as FBP with arbitrarily coarse angular sampling in planar geometries, and provides a different approximation from the Feldkamp-Davis-Kress (FDK) algorithm in the cone-beam geometry. Although we used it to emulate a virtual bow-tie, our dual-rotation acquisition framework is intrinsically related to region-of-interest (ROI) imaging through the truncated acquisition. With few or no modification of the proposed reconstruction methods, we successfully addressed the problem of ROI imaging in the context of dual-rotation acquisitions
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Zou, Congming. "SOIL MANAGEMENT AND NITROGEN DYNAMICS IN BURLEY TOBACCO ROTATIONS." UKnowledge, 2015. http://uknowledge.uky.edu/pss_etds/64.
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Agronomic practices, including tillage, crop rotation and N fertilization, have been developed to efficiently manage soil N dynamics and crop N nutrition. These practices can affect soil organic carbon (SOC) and soil total nitrogen (STN) sequestration, and consequently influence soil nitrogen mineralization (SNM) and crop N nutrition. However, little research has been systematically and simultaneously conducted to examine the effect of agronomic management on (1) SOC and STN stocks; (2) SNM; and (3) crop N nutrition. Burley tobacco (Nicotiana tobacum L.) is a N demanding crop and subject to inefficiency in N fertilization. Moreover, conservation tillage and rotation have been integrated into traditionally tillage intensive tobacco cropping systems. Thus, a tobacco tillage and rotation study was used to test how agronomic practices can affect N dynamics and crop N status in a series of sequential experiments.
Firstly, different tobacco production systems were utilized to investigate the effects of tillage and rotation on soil aggregate stabilization and associated SOM sequestration. No-tillage and rotation management enhanced SOC and STN stocks, mainly by increasing the proportion of macroaggregates and SOC and STN concentrations.
Secondly, a series of studies were conducted on SNM, including: (1) comparison of laboratory and in situ resin-core methods in estimating SNM; (2) evaluation of the influence of N fertilizer application on SNM; and (3) comparison of chemical indices for predicting SNM across management treatments over time. Laboratory method had different results relative to in situ method due to sample pretreatments. Fertilizer N application had a priming effect on SNM, but priming depended on both the N fertilizer rate and the background SOM level. The effect of rotation/tillage treatments on SNM was stable across years and SOC appeared to be the best indicator of SNM among other soil carbon and N estimates.
Thirdly, a N fertilizer study for different tillage systems was conducted in 2012 and 2013. Crop parameters and plant available N (PAN) were collected to investigate the impact of tillage on tobacco production. Crop parameters showed that no-tillage can result in N deficiency in dry years. Similar PAN for both tillage methods suggested N deficiency in no-till tobacco was due to the crop’s lower N uptake capacity. In 2014, tobacco root analysis confirmed that no-tillage can result in less root exploration of the soil volume than conventional tillage.
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Frennessen, Sebastian. "A comparison of peak trunk rotational power and club head speed in elite golf players." Thesis, Högskolan i Halmstad, Bio- och miljösystemforskning (BLESS), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-31039.
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Abstract Background: Golf is a sport with a growing focus on the physical aspect of the game and its relationship to performance. Studies have determined a correlation between club head speed and performance in golf. Rotational power has proven to be an important factor for the club head speed. By examining the relationship between club head speed and rotational power, researchers has found that rotation power on the golfers dominant side have a moderate to high correlation with club head speed. Previous research has mostly investigated the peak rotational power on the dominant side. Furthermore, additional research is needed to examine the bilateral strength and its relationship to club head speed. Aim: The aim of this study was to examine the correlation between peak trunk rotational power and club head speed in elite golfers, and also to study the impact of bilateral rotational strength on club head speed. Methods: The study included 27 elite golf players (21 males, 6 females) age 19±2 years. The subjects attended two sessions where the first session included a club head speed test and the second session a rotation power test in the Quantum machine. The rotational peak power ratio (dominant/non-dominant side) were ranged from 1-27 (the closer to 1, the higher order) to study a linier relationship with club head speed. Spearman’s nonparametric rank correlations coefficient (rs) was used since the data was not normally distributed. Results: There was a moderate correlation between peak trunk rotational power on the dominant side and club head speed ( rs=0.58, p=0.01). The correlation between the peak trunk rotational powers on the dominant and non- dominant side was high, rs=0.82 (p=0.01). There were no significant correlation found between the ranged rotational peak power ratio and club head speed (rs=0.30, p=0.1). Conclusion: The current study found a slightly lower correlation between peak trunk rotational power and club head speed than found in earlier studies. The golfers in this study had symmetric strength in the trunk, other studies have shown that the rotational strength in golfer´s dominant side were higher than of the non- dominant side. The result of this study indicates that balance between the sides not necessarily has a relationship with how high the golfer’s club head speed is. Future research is needed to analyze the quadratic correlation between ratio and club head speed on a more advanced level. The results of this study can, if validated, be used for further researching and understanding of club head speed and golf performance.
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Krinchev, André Felipe Borges. "Desempenho produtivo de novilhos Nelore em pastejo rotativo de capim Marandu e capim Convert HD 364." Universidade Estadual de Londrina. Centro de Ciências Agrárias. Programa de Pós-Graduação em Ciência Animal, 2017. http://www.bibliotecadigital.uel.br/document/?code=vtls000214334.
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O presente trabalho teve como objetivo, avaliar o efeito da Brachiaria spp. cv. Mulato II (Convert) sobre o desempenho, qualidade de carne e características de carcaça de novilhos Nelore castrados na fase de recria e terminação em sistema de pastejo rotacionado em comparação com a Brachiaria brizantha cv. Marandu, nas mesmas condições. O experimento foi conduzido na Fazenda Figueira e Estação Experimental Agrozootécnica Hildegard Georgina Von Pritzelwitz, localizada no município de Londrina e de propriedade da Fundação de Estudos Agrários Luiz de Queiroz. A área experimental foi dividida em dois tratamentos (Marandu X Convert) com 20 hectares cada, divididos em quatro repetições por tratamento, com cinco piquetes de um hectare cada . Os animais foram manejados de acordo com a oferta de matéria seca de lâminas foliares (6,19% do peso vivo) em pastejo rotativo com 7 dias de ocupação e 28 dias de descanso. Foram utilizados 10 animais em cada repetição (testers), além de animais reguladores quando necessário. Para análises de desempenho, foram utilizados os 10 animais de cada repetição, enquanto para análises de carcaça e carne utilizou-se seis animais por repetição. Foram avaliadas caracteristicas de produção e bromatológicas das duas gramíneas. O delineamento experimental foi inteiramente casualisado com dois tratamentos e quatro repetições, os dados foram submetidos à análise de variância utilizando o programa estátistico R. Os animais alimentados em pastagens estabelecidas com capim Convert foram superiores em relação aos alimentados em pastagens estabelecidas com capim Marandu, tendo maior ganho médio diário durante o período experimental (0,682 kg X 0,605 kg), peso ao abate (470,45 kg X 451,43 kg), peso de carcaça quente (239,93 kg X 232,36 kg). Também foram superiores em relação aos valores de cor da carne. Para as variáveis rendimento de cortes (músculo, gordura e osso), espessura de gordura, área de olho de lombo, comprimento de músculo, acabamento, conformação, marmoreio, força de cizalhamento, pH final, perda de água por pressão e centesimal (matéria seca, proteína bruta, extrato etéreo e cinzas) não houve diferença significativa entre os tratamentos. Portanto, a melhor qualidade bromatológica (digestibilidade) do capim Convert proporcionou melhores resultados dos animais nele manejados, refletindo em melhores valores de desempenho individual, carcaça e qualidade de carne.The objective of this study was to evaluate the effect of Brachiaria spp. Cv. Mulato II (Convert) on performance, meat quality and carcass characteristics of Nellore steers castrated in the growing and finishing phase in rotational grazing system compared to Brachiaria brizantha cv. Marandu, under the same conditions. The experiment was conducted at the Figueira´s Farm and Experimental Station Hildegard Georgina Von Pritzelwitz, located in the municipality of Londrina and owned by the Foundation for Agrarian Studies Luiz de Queiroz. The experimental area was divided into two treatments (Marandu X Convert) with 20 hectares each, divided in four replications by treatment, with five paddocks of one hectare each. The animals were managed according to the dry matter of leaf blades offer (6,19% of body weight) in rotational grazing with 7 days of occupation and 28 days of rest. Ten animals were used in each replicate (testers), as well as regulatory animals when necessary. For performance analysis, the 10 animals of each replicate were used, while for carcass and meat analyzes six animals were used per replicate. Production and bromatological characteristics of the two grasses were evaluated. The experimental design was completely randomized with two treatments and four replicates, the data were submitted to the analysis of variance using the R statistic program. Animals fed on pastures established with Convert grass were superior than those fed on pastures established with Marandu grass, with higher average daily gain during the experimental period (0,682 kg X 0,605 kg), slaughter weight (470,45 kg X 451,43 kg), hot carcass weight (239,93 kg X 232,36 kg). They were also superior in relation to meat color values. For the variables yield of cuts (muscle, fat and bone), fat thickness, rib eye area, muscle lenght, finishing, conformation, shear force, marbling, final pH, pressure water loss and centesimal (dry matter, crude protein , ether extract and ash) there was no significant difference between the treatments. Therefore, the better bromatological quality (digestibility) of the Convert grass provided better results of the animals handled in it, reflecting in better values of individual performance, carcass and meat quality.
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Lebas, Étienne. "Étude et modélisation de la pyrolyse du charbon en four tournant." Vandoeuvre-les-Nancy, INPL, 1995. http://docnum.univ-lorraine.fr/public/INPL_T_1995_LEBAS_E.pdf.
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La pyrolyse de grains de charbon en four tournant permet de produire un coke réactif principalement utilisé en électrométallurgie. Le but de cette étude est d'analyser et de modéliser les différents phénomènes impliqués dans ce procédé afin d'améliorer le fonctionnement et la conduite de l'installation industrielle. La pyrolyse du charbon a été étudiée par thermogravimétrie et analysé chromatographique des gaz émis afin de déterminer la cinétique de dégagement de chaque constituant des matières volatiles. L’enthalpie de réaction de la pyrolyse a été mesurée par calorimétrie à flux différentiel. Le mouvement de la charge en four tournant a été étudié grâce à des expérimentations en four pilote. Les mesures effectuées concernent le temps de séjour moyen, la distribution des temps de séjour, le profil de chargement et le temps moyen passe par un grain en surface du talus. Des corrélations adaptées à la modélisation du mouvement de la charge ont été déterminées. Les transferts de chaleur ont fait l'objet d'une étude approfondie: ils incluent le transfert en régime transitoire à travers la paroi et le rayonnement paroi/solide qui est partiellement absorbé par le gaz qui s'interpose. La démarche adoptée pour la modélisation de ce procédé a consisté à simuler, dans un premier temps, la pyrolyse d'une particule isolée. Le modèle de grain ainsi établi a ensuite été inséré dans une représentation globale du four en tenant compte de l'hydrodynamique du réacteur, des transferts de chaleur entre la paroi, le solide et le gaz et des réactions de combustion des matières volatiles. Ce modèle a été validé grâce à un ensemble de mesures effectuées sur le four tournant industriel et utilisé avec succès pour l'amélioration du fonctionnement de cette installation
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Camela, Edoardo. "The growing importance of the ETF industry: the pros and cons of passive management." reponame:Repositório Institucional do FGV, 2015. http://hdl.handle.net/10438/14168.
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The aim of this project is the comparison between the pros and cons of passive and active management by conducting a statistical study of several strategies through Exchange-Traded Funds. In particular, the examination will go through the most passive strategy, namely buy & hold, to a different degree of active indexing management such as sector and/or asset class rotations based on bottom-up, top-down and technical indicators. The analysis show that active strategies, if properly implemented, obtain risk-adjusted returns substantially higher than a passive approach, overcoming the issues of transaction costs and diversification which are typically claimed by a passive management.
O objectivo deste projecto é a comparação entre os prós e contras de gestão passiva e ativa através da realização de um estudo estatístico de várias estratégias através dos Exchange-Traded Funds. Em particular, a análise vai passar pela estratégia mais passiva, ou seja, buy and hold, para um grau diferente de active indexing management, tais como rotações do sector e / ou classe de ativos com base no bottom-up, top-down e indicadores técnicos. A análise mostra que as estratégias ativas, se forem devidamente aplicadas, conseguem obter retornos ajustados ao risco substancialmente superiores quando comparados com uma abordagem passiva, superando as questões de custos de transação e diversificação que normalmente são reivindicadas por uma gestão passiva.
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FRANÇA, Ulysses Eugênio Duarte de. "Simulação do processo de calcinação de gipsita em forno rotativo com aquecimento indireto." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18555.
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CAPES
O processo de obtenção do gesso beta, que consiste na desidratação do minério da gipsita a uma temperatura entre 125 °C e 160°C, é realizado em fornos rotativos através de queima direta ou indireta. Os principais combustíveis utilizados neste processo no Polo Gesseiro do Araripe são a lenha, o coque de petróleo, o óleo BPF e gás natural. Esta dissertação estuda a modelagem matemática de um sistema de calcinação com aquecimento indireto utilizando dois combustíveis sólidos diferentes: a lenha e o coque de petróleo. A modelagem é feita por meio do Método dos Volumes Finitos em um modelo bidimensional de coordenadas cilíndricas. Através da simulação numérica é possível prever o perfil de temperatura em uma seção transversal do forno, tal como suas taxas de aquecimento. São observadas as influências de parâmetros como vazão mássica do combustível, percentual de excesso de ar na combustão e teor de umidade da lenha. Também é realizada uma comparação entre os processos utilizando a lenha e o coque com relação ao custo e à emissão de dióxido de enxofre (SO2).
The process of obtaining the beta plaster, which consists of dehydration of the gypsum ore under a temperature between 100°C and 160 °C, is performed in rotary kilns through direct or indirect burn. The main fuels utilized in this process at Araripe Gypsum District are firewood, petroleum coke, heavy fuel oil and natural gas. This dissertation studies the mathematical modeling of a calcination system with indirect heating using two different solid fuels: firewood and petroleum coke. The modeling is made by using the Finite Volume Method in a two-dimensional model of cylindrical coordinates. Through the simulation is possible to predict the temperature behavior in a cross section of the kiln, as well as its heating rates. It was analyzed the influence of parameter such as mass flow rate, percent excess combustion air and moisture content of the firewood. A comparison between the processes using firewood and coke is also conducted, concerning the cost and the sulfur dioxide (SO2) emission.
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Olsson, Malin. "Core endurance and correlation to spinal rotation mobility and hand grip strength in female horseback riders and soccer players." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-42363.
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Bakgrund: Bålstabilitet är nödvändigt för att hålla balansen och möjliggör kraftöverföring genom kroppen. Detta gör bålstabilitet viktigt i vardagliga sysslor, sportutföranden och för att minska risken för skada. En bättre förståelse över bålstabiliteten i olika sporter kan utveckla träningsprogram, inte bara för att förbättra bålstabiliteten, utan även för att förbättra den generella prestationen. Syfte: Syftet med denna studie var att undersöka skillnader i båluthållighet mellan unga kvinnliga ryttare och fotbollsspelare, och associationen med handgrepp styrka och rotationsrörlighet i ryggen. Metod: Båluthålligheten undersöktes med McGill’s båluthållighets test, mellan kvinnliga ryttare (n = 10) och fotbollsspelare (n = 10), ålder 16 – 20. Handgreppsstyrkan undersöktes med en handdynamometer och användes som en indikation av generell styrka. Ryggrotations testet undersöktes men en Myrinmätare. Shapiro-Wilks användes för att bekräfta normalfördelning av data. Oberoende t-test användes för att jämföra båluthållighet (sek.) mellan ryttarna och fotbollsspelarna. Signifikansnivån fastställdes till <0,05. Ett styrkeförhållande räknades ut (kg/kg kroppsvikt) och Pearsons korrelationskoefficient användes sedan för att undersöka associationen med båluthållighet (sek.). Pearsons korrelationskoefficient användes också för att undersöka associationen mellan medelvärdet av ryggrotation (°) och båluthållighet (sek.). Hög korrelation fastställdes när r> (0,7), måttlig korrelation när r = (0,3 – 0,7) och låg korrelation när r <0,3. Resultat: Resultaten visade att ryttarna hade bättre uthållighet i bålextensionen, jämfört med fotbollsspelarna (p = 0,006). Lateralflexionen av bålen visade ingen skillnad mellan ryttarna och fotbollsspelarna (p = 0,924; p = 0,423). Handgrepp styrkan visade måttlig korrelation med bålextensionen (r = 0,631; r² = 0,398) och båda sidor av lateralflexionen av bålen (r = 0,411; r² = 0,169; r = 0,615; r² = 0,378). Rotationsrörligheten i ryggen visade låg korrelation med samtliga båluthållighets tester (r >0,3). Slutsats: Resultaten indikerar få skillnader mellan ryttare och fotbollsspelare, vilket inte är tillräckligt för att fastställa någon slutsats. Korrelationen mellan handgreppsstyrkan och båluthållighet indikerar att bättre bålstabilitet associerar med mer generell styrka.Background: Core stability is necessary to keep balance and enables force to be transmitted through the body. This makes core stability important in everyday chores, sport performance and to reduce risk of injuries. A better understanding of the core stability in different sports can develop athletes training programs, not only to improve the core stability itself, but also to improve overall performance. Aim: The aim of this study was to examine the differences in core endurance between young female horseback riders and soccer players, and the core endurance association with hand grip strength and spinal rotation mobility. Methods: The McGill’s core endurance test was used to examine the core endurance between female horseback riders (n = 10) and soccer players (n = 10), age 16-20. The hand grip strength was examined with a hand grip dynamometer and was used to get an indication of overall body strength. The spinal rotation mobility was examined with a Myrin goniometer. Shapiro-Wilks was used to confirm the normality of the data. Independent sample t-test was used to compare core endurance time (sec.) between the horseback riders and the soccer players. The significant level was set at < 0.05. A strength ratio was calculated (kg/kg body weight), and the Pearson’s correlation coefficient was used for examining the association to core endurance (sec.). Pearson’s correlation coefficient was also used to examine the association between the spinal rotation mobility (°) and core endurance (sec.). High correlations were set at r > (0.7), moderate when r = (0.3- 0.7) and low when r < (0.3). Results: The result showed that horseback riders had better endurance in the trunk extensor test than the soccer players (p = 0.006). Hand grip strength showed moderate correlation with the endurance time of the trunk extensor test (r = 0.631, r² = 0.398), and with the lateral flexor tests (r = 0.411, r² = 0.169; r = 0.615, r² = 0.378). Low correlation was shown with the trunk flexor test (r = 0.197, r² = 0.039). The spinal rotation mobility test showed low correlation with all the core endurance tests (r >0.3). Conclusion: The results indicates few differences between the horseback riders and the soccer players, which is not enough to draw a conclusion. The correlation between hand grip strength and the core endurance tests indicates that a better core stability might be associated to an increased overall body strength.
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Watkins, Andrew. "Earth Rotation and Deformation Signals Caused by Deep Earth Processes." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1510767104519046.
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Rogister, Yves. "Modes normaux de modèles de Terre en rotation." Habilitation à diriger des recherches, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00773648.
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The normal-mode spectrum of rotating Earth models is made up of the seismic modes, the rotational modes and the spectrum of the liquid core. The local equations for the infinitesimal elastic-gravitational deformation, based on a Lagrangian perturbation of a spherically-averaged Earth model using the theory of hydrostatic equilibrium, are first established. A comparison is made between this approach and the classical global angular momentum approach to Earth rotation variations. The splitting of the seismic modes by rotation and ellipticity is then computed. Numerical investigation also shows that, by changing the structure of the liquid core, the rotational modes and core spectrum interact to give rise to avoided crossings, which provide a physically plausible mechanism to explain the observed double frequency of the Chandler wobble. The analogy with other oscillatory physical systems allows for a better understanding of the avoided crossing phenomenon.
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Marchini, Monikelly do Carmo Nascimento 1986. "Influência do grau de rotação do aparelho e do crânio na espessura da cortical óssea em imagens de tomografia de feixe cônico : Evaluation of the influence of the unit and skull rotation on cortical bone thickness in cone beam computed tomography images." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/290162.
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Orientador: Solange Maria de Almeida BóscoloTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: A tomografia computadorizada de feixe cônico (TCFC) tem sido uma ferramenta de auxílio no diagnóstico, com várias aplicações clínicas. Devido ao aumento das diversas possibilidades de aquisição da imagem, há uma grande necessidade de um constante ajuste da imagem para cada proposta de diagnóstico. A avaliação da cortical óssea é importante para os casos de planejamento de implante imediato e para os casos em que há a necessidade de movimentação ortodôntica extensa. Entretanto, alguns fatores de qualidade de imagem devem ser considerados para uma acurada visualização da cortical óssea. Assim, com o presente estudo avaliou a influência do grau de rotação do aparelho, 3600 e 1800, bem como a influência de diferentes posições do crânio na avaliação da espessura da cortical óssea em imagens de TCFC. Para tanto, foram utilizados 11 crânios de humanos nos quais foram selecionados 59 dentes da maxila e mandíbula para avaliação de suas corticais ósseas. As imagens foram adquiridas no aparelho de TCFC Accuitomo 170, com voxel de 0,16mm, em quatro diferentes aspectos com relação à rotação do aparelho e posição do crânio respectivamente (protocolo 1: 3600/00; protocolo 2: 1800/00; protocolo 3: 1800/900; protocolo 4: 1800/1800). Para a avaliação das imagens, a cortical óssea foi classificada em três grupos de acordo com a condição ou espessura (cortical ausente, cortical fina e cortical espessa). No total 472 imagens bidimensionais (2D), referentes a cortes sagitais, foram avaliadas por três radiologistas previamente calibrados. Para concordância intra e interobservador foi utilizado o teste kappa e para avaliação das espessuras das corticais ósseas em relação ao real e entre os diferentes tipos de imagem foi utilizado o teste de Wilcoxon Signed Ranks. O teste de Kappa ponderado foi utilizado para comparar as diferentes condições da espessura óssea nos quatro protocolos de imagem. O nível de significância estabelecido foi de 95% (?=0,05). Os resultados obtidos mostraram que a concordância intraobservador variou de quase perfeita (k=0,87) a moderada (k=0,50) e a concordância interobservador variou de substancial (k=0,79) a moderada (k=0,56). De acordo com os resultados obtidos, observou-se que apenas para o protocolo 1 na região da cortical lingual, não houve diferença estatística entre as imagens e o padrão-ouro. Quando avaliando a cortical lingual, os maiores valores de concordância foram observados no protocolo 3, quando esta era ausente (k=0,80) e fina (k=0,47), já para cortical lingual espessa, o mais concordante foi o protocolo 2 (k=0,60). Avaliando-se somente a cortical vestibular, quando esta era ausente, o protocolo 3 exibiu o maior valor de concordância (k=0,61), enquanto que o protocolo 4 foi o mais concordante para cortical vestibular fina (k=0,38) e o protocolo 2 para a cortical vestibular espessa (k=0,40). Concluiu-se que o diagnóstico da espessura da cortical óssea não apresenta concordância perfeita com as imagens de TCFC, exceto para a região da cortical lingual no protocolo 1. Houve uma maior dificuldade de diagnóstico para a cortical vestibular em relação a lingual. Além disso, quando a espessura é mais fina, mais difícil é o diagnóstico
Abstract: The cone beam computed tomography (CBCT) has been a complement tool in diagnosis of many clinical applications. Due to the increase of the various possibilities of imaging, there is a great need for an image adjustment for each proposal to be diagnosed. The evaluation of cortical bone is important for implants pos-extraction placement and in cases requiring extensive orthodontic movement. However, some factors of image quality should be considered for accurate visualization of cortical bone. Thus, this study aimed to evaluate the influence of the arc rotation (3600 and 1800), and the influence of different positions of the skull to assess the thickness of buccal and lingual cortical bone in CBCT images. For this, 59 teeth of 11 human skulls in both arcs were selected. Images were made on Accuitomo 170 CBCT. The voxel size used was 0.16 mm. Four different aspects of image regarding the rotation of the device and position of the skull were made respectively (protocol 1: 3600/00; protocol 2: 1800/00; protocol 3: 1800/900; protocol 4: 1800/1800). For evaluation of the images, the cortical bone was classified into three groups according to the condition or the thickness (absent cortical, thin cortical, and thick cortical). A total of 472 two-dimensional images (2D) in sagittal sections were evaluated by three radiologists previously calibrated. For intra- and interobserver agreement kappa test was used. Wilcoxon Signed Ranks test was used to assess the cortical bone thickness compared to the gold standard and among different protocols. Ponderate Kappa test was used to compare conditions of cortical bone among protocols. The significance level was set at 95% (?=0.05). The results showed that the intraobserver agreement ranged from almost perfect (k=0.87) to moderate (k=0.50) and interobserver agreement ranged from substantial (k=0.79) to moderate (k=0.56). According to the results obtained, the protocol 1 showed that no statistical difference between the images and the gold standard was found only in lingual cortical bone region. When evaluating lingual cortical, higher reliability values was found with protocol 3 for absent (k=0.80) and thin (k=0.47), while for thick cortical in lingual side, the more consistent was the protocol 2 (k=0.60). Evaluating only buccal cortical side, the protocol 3 obtained the best agreement value for absent, (k=0.61), while the protocol 4 was better for thin cortical in buccal side (k=0.38), and protocol 2 for thick cortical in buccal side (k=0.40). It was concluded that the diagnosis of cortical bone thickness do not show agreement with CBCT images, except for lingual cortical bone in the protocol 1. There was more difficult diagnosis in buccal cortical compared to lingual cortical side. In addition, when the thickness is thinner more difficult the diagnosis is
Doutorado
Radiologia Odontologica
Doutora em Radiologia Odontológica
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Chen, Chun-Ming. "Data Summarization for Large Time-varying Flow Visualization and Analysis." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469141137.
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Aquino, João José Redondo de. "Structural numerical simulation code development with isogeometric anakysis (IGA)." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22375.
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Mestrado em Engenharia MecânicaIn the present day most product development industries uses the Finite Element Method (FEM) for structural analysis. Designers model the product geometries using Computer-Aided Design (CAD) software, the geometries are then fitted for analysis, by the analysts, with a mesh approximation that inevitably results in loss of accuracy. Achieving the best geometry description for complex components can be a complex task and it can take a lot of time. Considering this drawback, a new method was developed which takes advantages of curve representation tools and uses them as bases for analysis. Aiming for no loss of geometrical precision, this new method has been called "Isogeometric Analysis" (IGA). The smoothness of Spline representations used in Isogeometric Analysis can be useful for a particular branch of structural analysis which is the analysis of plates and shells. The classic thin plate theory developed by Gustav Kirchhoff requires a geometry description with C1 continuity between elements which is normally defined by high order polynomial functions, which typically represents a problem with the piecewise Lagrangian shape functions used in conventional FEM. The present work explores parametric descriptions used as basis for Isogeometric Analysis, such as Bézier curves, B-splines and NURBS, taking advantage of its smoothness to develop formulations for thin plate elements. The 4-node rectangular derived by Melosh, O. Zienkiewicz and Y. Chung called MCZ thin plate element based on Kirchhoff assumptions, was the starting point to build up to a NURBS-based thin plate element. MCZ thin plate elements, NURBS-based thin plate elements (with different order geometries) and Abaqus commercial software shell elements are evaluated by means of classical plate benchmarks comparing the elements convergences and overall performance. It can be shown that the proposed NURBS-based formulation is reliable for the analysis of thin structures.
Nos dias de hoje a maioria da indústria de desenvolvimento do produto utiliza o Método dos Elementos Finitos (MEF) na análise estrutural. Os desenhistas modelam o produto através de ferramentas de Computer-Aided Design (CAD). As geometrias são depois ajustadas para a análise pelos analistas que constroem uma aproximação através de uma malha de elementos finitos, o que inevitavelmente resulta numa perda de precisão geométrica. Para conseguir a melhor aproximação à geometria original para componentes complexos o processo pode ser complicado e pode consumir muito tempo. Considerando esta desvantagem foi desenvolvido um novo método que tira partido da descrição geométrica das ferramentas de desenho e utiliza as funções base das curvas para analise, com o objectivo de não haver perda de precisão geométrica, este novo método tem o nome de “Análise Isogeométrica” (IGA). A suavidade das geometrias Splines usadas na análise isogeometrica pode ser muito útil num ramo particular da análise estrutural, no estudo das placas e cascas. A teoria clássica de análise de placas finas de Kirchhoff requer uma descrição geométrica que tenha continuidade C1 entre elementos, que é normalmente definida por polinómios de ordem elevada, que são tipicamente um problema para as funções de forma Lagrangeanas usadas em MEF. O presente trabalho explora as descrições geométricas utilizadas como funções de forma para a análise isogeométrica como as curvas de Bézier, as B-splines e as NURBS, tirando vantagem da facilidade de estas conseguirem a requerida continuidade entre elementos para criar elementos de placas finas com as funções de base NURBS como funções de forma. É utilizado o elemento de placa fina MCZ desenvolvido por Melosh, O. Zienkiewicz e Y. Chung com base nas premissas de Kirchhoff como ponto de partida para desenvolver o elemento com base em NURBS. No fim os elementos de placas finas MCZ, os elementos com funções de base NURBS (com geometrias de diferentes ordens) e elementos do tipo casca do software comercial Abaqus são avaliados através de uma série de diferentes problemas clássicos de placas, comparando a convergência e o desempenho global. É possivel ver que a formulação proposta é fidedigna na análise de estruturas de placa fina.
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Pichon, Guillaume. "Dynamique rotationnelle couplée de la dérive géomagnétique vers l'ouest et de la super-rotation de la graine terrestre." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC271/document.
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Ce travail de thèse se concentre sur la dynamique rotationnelle du système couplé graine, noyau externe et manteau. Notre modèle inclut en effet deux couples électromagnétiques directs aux limites du noyau fluide et un couple gravitationnel entre la graine et le manteau. La dynamique rotationnelle est décrite par quatre cisaillements typiques et étudiés dans des simulations numériques convectives de la géodynamo reproduisant les principales caractéristiques du champ magnétique terrestre et de sa variation séculaire. Celle-ci est principalement représentée par la dérive géomagnétique vers l’ouest de taches de flux magnétique à la CMB, concentrée à l’équateur de l’hémisphère Atlantique, et bien documentée pour les quatre derniers siècles. Nous fournissons des contraintes sur la rotation différentielle de la graine en exprimant son lien avec la dérive géomagnétique vers l’ouest. Ceci est réalisé par la formulation et la validation de modèles dynamiques de couples électromagnétiques. Au long terme, le cisaillement global dans le noyau fluide est réparti entre la dérive géomagnétique vers l’ouest et la rotation différentielle de la graine, dans des proportions contrôlées par l’état des couplages. Puisqu’une estimation actuelle de ce cisaillement est proche de la vitesse de la dérive géomagnétique vers l’ouest, nous concluons que la rotation différentielle moyenne de la graine est proche de zéro. En ce qui concerne ses fluctuations, l’intensité du couplage gravitationnel est le paramètre dominant. Cette observation place une limite sur les fluctuations décennales de la rotation différentielle de la graine, qui ne devraient pas excéder quelques centièmes de degré par anThis PhD work focuses on the rotational dynamics of the coupled inner core - outercore - mantle system. The conservation of the angular momentum our coupled Earth model indeed involves two direct electromagnetic torques at the fluid core boundaries and a remote gravitational torque between the inner core and the mantle. The rotational dynamics is described by four typical shears and studied in convective numerical simulations of the geodynamo which are able to reproduce the main characteristics of the geomagnetic field and its secular variation. This secular variation is mainly embodied by the westward drift of magnetic flux patches at the CMB, concentrated on the equator of the Atlantic hemisphere, and is well documented for the last four centuries. We provide constrains on the inner core differential rotation by expressing its link to the geomagnetic westward drift. This is performed through the formulation and the validation of dynamical electromagnetic torque models, which are then introduced in the conservation of the angular momentum of the system. In the long-term state, the global shear in the fluid outer core is distributed between the westward drift and the differential rotation of the inner core, in proportions controlled by the state of couplings. As a present day estimate of this shear is close to the observed westward drift, we conclude there is no differential rotation of the inner core on time-average. In the time-dependent state, we observed that the strength of gravitational coupling is the dominant parameter. This places limit on the decadal fluctuations of the inner core differential rotation, which should not exceed a few hundredths of degree per year
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Lubrano, Jean-Louis. "Etude théorique de la turbulence homogène soumise à des effets de rotation et modélisation en vue de l'implantation au sein d'un code résolvant les équations de Navier-Strokes." Ecully, Ecole centrale de Lyon, 1993. http://bibli.ec-lyon.fr/exl-doc/TH_T1482_jllubrano.pdf.
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La rotation a une influence certaine sur la turbulence homogène par le biais des forces de Coriolis. Ces effets, mal pris en compte par les modélisations classiques, nécessitent une approche plus élaborée. Un recours possible est la recherche d'informations dans l'espace spectral où les différents termes de l'équation du tenseur spectral ont une signification physique plus facile à appréhender. Ainsi a-t'il été mis clairement en évidence une partition de l'anisotropie en une composante caractérisant la directivité du champ énergétique et une composante définissant sa polarisation. Cette séparation s'accompagne de comportements différents tant sur les termes linéaires que non linéaires et permet une modélisation en accord avec les phénomènes observés. Une extension à une turbulence homogène soumise à une déformation plus générale a été proposée dans le cadre de ce travail. Malheureusement, les résultats laissent supposer qu'il est nécessaire d'appliquer un développement au second ordre et il a été préféré une modélisation provenant d'une étude américaine de W. C. Reynolds, cette dernière se rattachant a la théorie spectrale. Un modèle construit à partir de ces divers éléments a été implanté au sein d'un code de calcul Navier Stokes sur une configuration de type canal plan avec effets de rotation. Cette étude permet donc d'avoir une base de travail confortable, afin d'obtenir une modélisation future dont les résultats devraient s'avérer probants.
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Dumitriu, Dan. "Modélisation dynamique des systèmes articulés par des vecteurs translation et des matrices rotation : prise en compte des rigidités par des multiplicateurs de Lagrange : simulations du mouvement à l'aide d'un code en C++." Poitiers, 2003. http://www.theses.fr/2003POIT2258.
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Nous proposons une modélisation dynamique des systèmes articulés qui paramétre la position de chaque solide par les 3 composantes de son vecteur translation et les 9 coefficients de sa matrice rotation. On tient compte des rigidités de chaque solide et des articulations entre solides par des multiplicateurs de Lagrange. Le mouvement est régi par un système algébro-différentiel ayant comme partie différentielle les équations de Lagrange et comme partie algébrique les équations de liaison. Nous construisons un code de calcul orienté objet en C++ qui résout le système algébro-différentiel par un algorithme de projection. Ce code est validé par la simulation du mouvement d'une plate-forme. Dans le cas d'Euler-Lagrange du solide à point fixe, la matrice 3x3 symétrique des 6 multiplicateurs de Lagrange associés à la rigidité du solide est négative, de plus ses valeurs propres se révèlent constantes. Cette matrice représente la moyenne volumique du tenseur des contraintesOur proposal for dynamical modelling of articulated systems consists in parameterising the position of each solid by the 3 components of its translation vector and the 9 components of its rotation matrix. The rigidities of each solid and the articulations between solids are taken into account by Lagrange multipliers. The motion is governed by an algebra-differential system bringing together constraint equations and Lagrange equations. We have created an oriented object C++ program solving the algebra-differential system by a projection algorithm. This program is validated by simulating the motion of a platform. For the Euler-Lagrange solid, the Lagrange multipliers associated to the solid rigidity are grouped together in a 3x3 symmetrical matrix turning out to be negative. Moreover the eigenvalues of this matrix are constant. The Lagrange multipliers matrix is directly related to the stress tensor volume average
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Legros, Hilaire. "Sur quelques problemes de dynamique planetaire." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13173.
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La rotation et la deformation d'une planete, sous l'action de certaines forces, interagissent entre elles: cette interaction, decrite par les nombres de love, est etudiee dans le cas d'une planete composee d'un noyau liquide, d'un manteau elastique et d'une couche fluide superficielle. L'elasticite du manteau et la geometrie du noyau fluide determinent la periode chandlerienne et la periode presque diurne associee a la rotation quasi-rigide du noyau; ils modifient les resonances associees et perturbent les rotations de l'axe de la terre dans l'espace et les mouvements de grande amplitude dans le noyau
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Godard, Paul. "Parallélisation et passage à l'échelle durable d'une chaïne de traitement graphique pour l'impression professionnelle." Thesis, Strasbourg, 2019. https://publication-theses.unistra.fr/public/theses_doctorat/2019/Godard_Paul_2019_ED269.pdf.
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Les nombreuses avancées du vaste domaine de l’impression professionnelle ont permis la multiplication des objets imprimés dans nos quotidiens. Désormais, la flexibilité introduite par les procédés d’impression numérique promet d’associer les souhaits de personnalisation avec les avantages de la production de masse. La rapide évolution des usages et des technologies, caractérisée par des fermes d’impression toujours plus grandes et des presses numériques toujours plus rapides, pose des problèmes inédits aux systèmes informatiques actuels qui pilotent les imprimantes. Dans cette thèse, nous explorons de nouvelles techniques inspirées des systèmes de calcul haute performance afin d’accélérer l’exécution des traitements graphiques indispensables à l’impression numérique. Nous introduisons pour cela une architecture de calculs distribués flexible exploitant des techniques de traitement et de synchronisation optimisées. Nous détaillons les principes de fonctionnement et les subtilités de l’implémentation de nos travaux qui permettent de respecter les contraintes spécifiques des flux de données produits. Nous réalisons une évaluation complète de notre solution qui y démontre ses excellentes performances et sa viabilitéThe strong and continuous improvements in the professional printing field have led to the ubiquity of printed objects in our daily life. The flexibility introduced by the digital printing process promises to associate extensive customization with mass production. The quick growth of printing usages and technologies, illustrated by wider printer farms and faster digital presses, leads to original challenges for the computer system in charge of driving them. In this thesis, we explore new approaches inspired by the high performance computing field to speedup the graphics processing necessary to digital printing. To achieve this goal, we introduce a distributed system which provides the adequate flexibility and performance by exploiting and optimizing both processing and synchronization techniques. We present our architecture up to the subtle parts of its implementation which allows our solution to meet the specific constraints on generating streams for printing purpose. We perform a complete evaluation of our solution and provide experimental evidence of its great performance and viability
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Andersson, Josefin, and Sandra Lidholm. "Revisorsrotation : Rotationsreglernas påverkan på revisorns oberoende, revisionskvalitet samt revisorns legitimitet." Thesis, Högskolan i Skövde, Institutionen för handel och företagande, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-17161.
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Bakgrund: Tidigare forskning visar både för- och nackdelar med rotationsregler för revisorer. Vissa menar att revisorns oberoende och revisionskvaliteten stärks i samband med rotationsregler då revisorn inte får en nära relation med sin klient. Samtidigt anger andra forskare att revisorns oberoende och revisionskvaliteten blir sämre då rotationsregler tillämpas. En revisor ska oavsett uppdrag alltid revidera utifrån god revisorssed och alltid vara oberoende vid sina uppdrag. Tidigare forskning anger att revisorns oberoende ses som en professionell tillgång, om en revisor agerar oaktsamt skulle detta påverka revisorns legitimitet och förtroendet för revisorer kan därmed ifrågasättas av samhället. Problemformulering: Vilken påverkan har rotationsreglerna på revisorns oberoende? Vilken påverkan har rotationsreglerna på revisionskvaliteten? Syfte: Studiens syfte är att ur ett legitimitetsperspektiv bidra med påskrivande revisorers uppfattningar kring rotationsreglernas påverkan på revisorns oberoende samt revisionskvaliteten. Studien kommer också bidra med förståelse för hur relationen mellan revisor och klient påverkar revisorns oberoende och revisionskvaliteten. Då det är relationen som studeras kommer vänskapshotet inom den lagstadgade analysmodellen att beskrivas. Metod: Sju intervjuer med påskrivande revisorer på mindre eller medelstora revisionsbyråer har genomförts. De intervjuade revisorerna har valts genom ett strategiskt urval för att bidra med förståelse om det valda området. Resultat och slutsats: Studien visar att rotationsregler inte påverkar revisorns faktiska oberoende men att det påverkar revisorns synbara oberoende, vilket innebär att reglerna stärker samhällets förtroende för revisorer. Rotationsregler kan också förbättra revisionskvaliteten då en revisor som haft ett uppdrag under flera års tid kan utföra granskningen av slentrian och inte är uppmärksam. Dock tyder studiens resultat på att rotationsregler kan försämra revisionskvaliteten under det första året av ett uppdrag eftersom en revisor bör ha kunskap om klientens verksamhet för att kunna utföra revisionen med hög kvalitet.Background: Research has shown both advantages and disadvantages of rotation rules for auditors. Some argue that the auditor's independence and the audit quality are strengthened in connection with rotation rules, since the auditor does not get a close relationship with clients. At the same time, other researchers indicate that the auditor's independence and the audit quality will deteriorate when rotation rules are applied. An auditor must, regardless of assignment, always revise on the basis of good auditing practice and always be independent in the assignments. Research indicates that the auditor's independence is seen as a professional asset, if an auditor acts negligently, this would affect the auditor's legitimacy, and confidence in auditors can thus be questioned by society. Questions: What impact does rotation rules have on the auditor's independence? What impact does rotation rules have on the audit quality? Purpose: The purpose of the study is to contribute, from a legitimacy perspective, the perceptions of auditors on the impact of the rotation rules on the auditor's independence and the audit quality. The study will also contribute with an understanding of how the relationship between auditor and client affects the auditor's independence and the audit quality. When it is the relationship being studied, the friendship threat within the statutory analysis model will be described. Method: Seven interviews with authorized auditors in small or medium-sized auditing firms have been conducted. The interviewed auditors have been chosen through a strategic selection to contribute with understanding of the chosen area. Results and conclusion: The study shows that rotation rules do not affect the auditor's independence in fact, but that it affects the auditor's independence in appearance, which strengthens society's confidence in auditors. Rotational rules can also improve the audit quality as an auditor who has had an assignment for several years can carry out the auditing by routine and not be attentive enough. However, the study's results suggest that rotation rules may impair the audit quality during the first year of an assignment because an auditor should have knowledge of the client's activities in order to perform the audit with high quality.
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Patias, Josiele. "Zoneamento geotécnico com base em krigagem ordinária e equações multiquádricas: barragem de Itaipu." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-06122011-111314/.
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Esta tese apresenta um estudo com base em zoneamentos de parâmetros geotécnicos provenientes de sondagens rotativas, realizadas no maciço basáltico, localizado na área das obras de Usina Hidrelétrica de Itaipu (Foz do Iguaçu - PR). Estes zoneamentos foram realizados a partir de interpolação dos dados por meio de krigagem ordinária e equações multiquádricas. Os dados provenientes de sondagens rotativas analisados nesta pesquisa são: Rock Quality Designation (RQD), grau de alteração, grau de consistência e grau de fraturamento. Os métodos de interpolação foram avaliados para o parâmetro de RQD, pois tais métodos apresentam características matemáticas similares, assim, foram comparadas interpolações realizadas com krigagem ordinária e equações multiquádricas, sendo comprovada a similaridade destes métodos com dados reais. Sendo assim, os demais parâmetros, por se caracterizarem como variáveis categóricas e, portanto, discretas, e apresentarem complexidade para realização da análise variográfica dos dados (semivariograma experimental e modelagem do semivariograma), foram interpolados apenas pelo método das equações multiquádricas. A validação dos dados interpolados foi realizada a partir de um estudo de caso relativo ao comportamento hidrogeotécnico do maciço rochoso, o qual é monitorado por piezômetros do tipo standpipe. Esta validação mostrou que os métodos utilizados para obter os zoneamentos e os parâmetros de modelagem considerados foram adequados, pois se verificou alta correlação entre as tendências de comportamento obtidas pelas interpolações dos parâmetros geotécnicos do maciço rochoso e o comportamento revelado pelo conjunto de piezômetros instalados no mesmo local. Este trabalho teve como etapa primordial o levantamento de dados históricos relativos às investigações geológico-geotécnicas da área das obras de Itaipu, a partir destes dados foi composto um mapa interativo de localização dos diferentes tipos de investigação realizados no substrato rochoso e terroso. Tal documento permite uma busca rápida e dinâmica das informações geotécnicas, pois apresenta como referência a própria planta da barragem de Itaipu. Cada ponto de investigação está vinculado ao perfil geotécnico. As investigações utilizadas neste mapa são: sondagem rotativa, sondagem à percussão (SPT), ensaio de cone (CPT) e poço manual. Sendo assim, o resgate das informações históricas obtidas nas campanhas de investigação geotécnica na área das obras de Itaipu, resultou na compilação dos dados de forma digital, em que foi elaborado um conjunto de planilhas com formato capaz de ser utilizado em diferentes Sistemas de Informação Geográfica e de interpolação de dados georreferenciados.This thesis presents a study based on the zoning of geotechnical parameters resulting from core boring, carried out in the basaltic bedrock located in the area of the Itaipu Hydroelectric Power Plant (Foz do Iguaçu - PR). These zonings were carried out based on the interpolation of the data by means of ordinary kriging and multiquadric equations. The data provided by core boring analyzed in this research are: Rock Quality Designation (RDQ), degree of alteration, degree of consistency and degree of fracturing. The interpolation methods were evaluated for the RQD parameter, since such methods present similar mathematical characteristics; therefore, comparisons were made between interpolations resulting from ordinary kriging and multiquadric equations, demonstrating the similarity of these methods with real data. In this manner, the remaining parameters due to being categorized as categorical variables and, therefore, discrete, and presenting complexity for the execution of the variographic analysis of the data (experimental semi-variogram and modeling of the semi-variogram), were interpolated only by the method of the multiquadric equations. The validation of the interpolated data was carried out on the basis of a case study relating to the hydrogeotechnical behavior of the bedrock mass, which is monitored by standpipe piezometers. This validation showed that the methods employed to obtain the zonings and the modeling parameters chosen were adequate, since a high correlation was verified between the behavior trends obtained by the interpolations of the geotechnical parameters of the bedrock mass and the behavior revealed by the set of piezometers installed in the same site. The primordial stage of this job was the acquisition of historical data relating to the geological-geotechnical investigations in the area of Itaipu Dam. This data served as a starting point for the composition of an interactive map showing the location of the different types of investigations carried out in the rock and earthen masses. The resulting document permit a rapid and dynamic search through the geotechnical information, since it presents as its reference the plan view of the Itaipu dam itself. Each point of investigation is linked to the geotechnical profile. The investigations utilized in this map are: core boring, standard penetration test (SPT), cone penetration test (CPT) and manual pit. In this manner, the recovery of the historical information obtained by the geotechnical investigation the Itaipu Dam area resulted in data compilations in digital format, based upon which, a set of tabular forms was obtained of a type capable of being utilized in different Systems of Geographical Information and of interpolation of geo-referenced data.
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Jedlička, Michal. "Statická analýza pohyblivé výškové budovy." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372265.
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The thesis is about static analysis of moving skyscraper (inspired by The Dynamic Tower). There is a rotation of each particular floor around its axis independently on each other. In this thesis, moving skyscraper is solved as a whole piece with specialization in the moving floors and their mounting on the core of the building.
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Kazaz, Ilker. "Dynamic Characteristics And Performance Assessment Of Reinforced Concrete Structural Walls." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611712/index.pdf.
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The analytical tools used in displacement based design and assessment procedures require accurate strain limits to define the performance levels. Additionally, recently proposed changes to modeling and acceptance criteria in seismic regulations for both flexure and shear dominated reinforced concrete structural walls proves that a comprehensive study is required for improved limit state definitions and their corresponding values. This is due to limitations in the experimental setups, such that most previous tests used a single actuator at the top of the wall, which does not reflect the actual loading condition, and infeasibility of performing tests of walls of actual size in actual structural configuration. This study utilizes a well calibrated finite element modeling tool to investigate the relationship between the global drift, section rotation and curvature, and local concrete and steel strains at the extreme fiber of rectangular structural walls. Functions defining more exact limits of modeling parameters and acceptance criteria for rectangular reinforced concrete walls were developed. This way a strict evaluation of the requirements embedded in the Turkish Seismic Code and other design guidelines has become possible. Several other aspects of performance evaluation of structural walls were studied also. Accurate finite element modeling strategies and analytical models of wall and frame-wall systems were developed for seismic response calculations. The models are able to calculate both the static and dynamic characteristics of wall type buildings efficiently. Seismic responses of wall type buildings characterized with increasing wall area in the plan were analyzed under design spectrum compatible normal ground motions.
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Ozgur, Cagri. "Influence of cross-frame detailing on curved and skewed steel I-girder bridges." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42769.
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Curved and skewed I-girder bridges exhibit torsional displacements of the individual girders and of the overall bridge cross-section under dead loads. As a result, the girder webs can be plumb in only one configuration. If the structure is built such that the webs are plumb in the ideal no-load position, they generally cannot be plumb under the action of the structure's steel or total dead load; hence, twisting of the girders is unavoidable under dead loads. The deflected geometry resulting from these torsional displacements can impact the fit-up of the members, the erection requirements (crane positions and capacities, the number of temporary supports, tie down requirements, etc.), the bearing cost and type, and the overall strength of the structure. Furthermore, significant layover may be visually objectionable, particularly at piers and abutments.
If the torsional deflections are large enough, then the cross-frames are typically detailed to compensate for them, either partially or fully. As specified in Article C6.7.2 of the AASHTO LRFD Specifications, different types of cross-frame detailing methods are used to achieve theoretically plumb webs under the no-load, steel dead load, or total dead load conditions. Each of the cross-frame detailing methods has ramifications on the behavior and constructability of a bridge. Currently, there is much confusion and divergence of opinion in the bridge industry regarding the stage at which steel I girder webs should be ideally plumb and the consequences of out-of-plumbness at other stages. Furthermore, concerns are often raised about potential fit-up problems during steel erection as well as the control of the final deck geometry (e.g., cross-slopes and joint alignment). These influences and ramifications of cross-frame detailing need to be investigated and explained so that resulting field problems leading to needless construction delays and legal claims can be avoided.
This dissertation addresses the influence of cross-frame detailing on curved and/or skewed steel I girder bridges during steel erection and concrete deck placement by conducting comprehensive analytical studies. Procedures to determine the lack-of-fit forces due to dead load fit (DLF) detailing are developed to assess the impact of different types of cross-frame detailing. The studies include benchmarking of refined analytical models against selected full scale experimental tests and field measurements. These analytical models are then utilized to study a variety of practical combinations and permutations of bridge parameters pertaining to horizontal curvature and skew effects. This research develops and clarifies procedures and provides new knowledge with respect to the impact of cross-frame detailing methods on: 1) constructed bridge geometries, 2) cross-frame forces, 3) girder stresses, 4) system strengths, 5) potential uplift at bearings, and 6) fit-up during erection. These developments provide the basis for the development of refined guidelines for: 1) practices to alleviate fit-up difficulties during erection, 2) selection of cross-frame detailing methods as a function of I-girder bridge geometry characteristics, and 3) procedures to calculate the locked-in forces due to DLF cross-frame detailing.
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Wu, Hung-Sheng, and 吳鴻昇. "Convection heat transfer from the surface of a non-isothermal rotating cone." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/68215262844246332311.
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碩士逢甲大學
機械工程學系
89
Heat transfer of laminar mixed convection from a non-isothermal rotating cone is studied numerically. Results show that the Prandtl number and the surface temperature differences between the surface and the ambient air, i.e., , are vital to the velocity and the temperature field, it also reveals that the momentum transfer rate is comparable to the heat transfer rate at Pr=0.7, and heat transfer rate becomes greater than momentum transfer rate as increasing of the Prandtl number. Results also indicate that the Nusselt number decrease with increasing of ξ in the free convection dominate region (ξ< 0.4), it implies heat transfer rate suppressed by the cone rotation. While the Nusselt number increase with increasing of ξ and Pr in the region where forced convection dominated (ξ> 0.6), it means the forced convective heat transfer enhanced by the faster rotative motion and the higher Pr. Especially for the rotating cone with Pr=10 and m=-2, the colder air flows downward to repel the hotter air from the cone surface which tend to assist the heat transfer, as a result, the forced convection enhanced significantly under this condition.
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Lai, Yung-Ta, and 賴泳達. "Index Modulation Multiple Access with Rotation Code." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/nwpcq7.
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碩士國立清華大學
電機工程學系
107
In the fifth generation (5G) communication system, massive connectivity of users and devices, higher spectral efficiency (SE), higher energy efficiency (EE), better link reliability and lower latency are expected. Since the current LTE system that uses the Orthogonal Frequency Division Multiple Access (OFDMA) technique is less efficient to meet these requirements, one of the most popular solutions for 5G is non-orthogonal multiple access (NOMA) technique. However, most current code-domain NOMA solutions require user-specific codebook assignment, which require grant based transmission. Therefore, the motivation is to design a code-domain NOMA scheme that can facilitate grant free random multiple access. In this thesis, the “Index Modulation Multiple Access”(IMMA) scheme is proposed. IMMA is a codebook-based NOMA scheme that is inspired from the index modulation (IM) technique. To be specific, IMMA uses the active subcarriers and inactive subcarriers to make index indices, and the index indices can carry index bits in addition to the modulation signal bits. By adjusting different active subcarrier numbers and modulation types, the IMMA can reconfig and improve the spectral efficiency (SE) and energy efficiency (EE). The rotation code is proposed to resolve the inter-user interference (IUI) in contention based multiple access. Furthermore, different decoders such as the breath-first search sphere decoder (BFS-SD) and depth-first search sphere decoder (DFS-SD) are proposed to relieve the high computational complexity of the joint maximum likelihood (JML) decoder, the theoretical average bit error rate (ABER) upper bound is also derived. Our simulation results show that the BER of IMMA is improved with rotation code for better diversity. The SE and EE of IMMA are also better than OFDMA and sparse code multiple access (SCMA). In brief, we design a code-domain NOMA scheme that can facilitate grant free random multiple access, and has better SE, EE than OFDMA and SCMA.
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Seyed-Mahmoud, Behnam. "Wobble/nutation of a rotating ellipsoidal earth with liquid outer core : implementation of a new set of equations describing dynamics of rotating fluids /." 1994. http://collections.mun.ca/u?/theses,98622.
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"Analise termica de um regenerador rotativo." Tese, Biblioteca Digital da Unicamp, 2005. http://libdigi.unicamp.br/document/?code=vtls000377023.
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Veasey, Martin James. "The effects of core-mantle gravitational coupling on the rotational dynamics of Mercury." Master's thesis, 2010. http://hdl.handle.net/10048/1521.
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As Mercury orbits the Sun, solar induced gravitational torques give rise to a planetary libration. While undergoing this 88 day period libration, the axes of minimum moment of inertia of the mantle and solid core, if present, become misaligned, leading to a gravitational torque which initiates a free-mode of axial oscillation between the inner core and mantle. For a large gravitational torque, the free-mode period approaches the period of the libration forcing, and should participate in the planets libration response. The goal of this work is to determine whether Mercurys observed librations can be used to place constraints on the inner core structure. Perturbations in Mercurys rotation rate are simulated for a range of interior structures. For models where the free-mode interferes with the libration signature, a marginally better fit between model response and observations is obtained, compared to models which exhibit the libration signature alone.Geophysics
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Akiyama, Shizuka. "The role of rotation and magnetic fields in a core collapse supernova." Thesis, 2006. http://hdl.handle.net/2152/20984.
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While the process that converts implosion into explosion in core collapse supernovae is poorly understood, their observed asphericity provides new constraints on the physics of these events. Since pulsars are rotating and magnetized neutron stars, there is no doubt that rotation and magnetic fields are inherent to the exploding engine. We have shown that magnetic field amplification is an inevitable by-product of the differential rotation that accompanies core-collapse. We performed 1D core-collapse simulations of rotating iron cores with various rotational profiles and velocities. We found that differential rotation was a generic feature of rotating iron core collapse. As a result, the magnetorotational instability (MRI) generates magnetic fields of order 10¹⁵⁻¹⁷ G in a few tens of milliseconds where the negative shear is the strongest. Although magnetic fields of order 10¹⁵⁻¹⁷ G are very strong, they are not strong enough to modify the equation of state of degenerate electron gas near the proto-neutron star. The corresponding MHD luminosity available is ~10⁵² erg s⁻¹, which can modify the explosion dynamics if the power is sustained for a fraction of a second. When rotational effects are included, we found that there is a critical iron core rotation rate that gives the most rapidly rotating proto-neutron star, faster than which the rotational velocity of the proto-neutron star decreases due to centrifugal support. This non-monotonic behavior of post-collapse core rotation suggests that the progenitor of the most rapidly rotating proto-neutron star is not the most rapidly rotating iron core, but that those iron cores with nearly the critical initial rotation rate may produce the maximum proto-neutron star rotation, the strongest magnetic fields, and the most robust supernova explosions. Even small rotation may induce non-axisymmetric instabilities, which drive magneto-acoustic flux in to the mantle, transporting enegy out of the proto-neutron star to the region near the stalled shock. Further implications for rotation and magnetic fields, pulsars and magnetars, and jet formation mechanisms are discussed.text
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Chih-LunLiu and 劉誌倫. "Parallelized Rotation-Scaling-Translation-Invariant Template Matching on Embedded Multi-Core Platform." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/rj92gu.
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"Estudo do comportamento energetico apresentado por tres formas geometricas de laminas de enxada rotativa." Tese, Biblioteca Digital da Unicamp, 1997. http://libdigi.unicamp.br/document/?code=vtls000121238.
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SUNG, YI, and 宋懿. "Effect of Eight Weeks Core Stability Training Combine Rotation Training on College Baseball Player’s Hitting Performance." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/9mkn8f.
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碩士國立體育大學
運動保健學系
107
Hitting is one of the key factors in the impact of a baseball game. When hiting, the trunk should be stabilized first, then use the lower limb strength to drive the waist to rotate, and connect to the upper limb to complete the swing action. The trunk core muscles play an important role in conacting the lower limbs to the upper limbs, so the intervention of the core muscle training may affect the hitting performance. Purpose: This study will explore the impact of eight-week core stability and rotational training interventions on the performance of college players. Methods: 24 general college baseball players, test the Double-Leg-Lowering-Test (core stability), dynamic abdominal, back muscle ability and medicine ball throwing (rotation ability), as a core ability index; measuring swing speed and ball exit velocity(BEV) as performance indicator. Two-way Anova was used to compare the difference between the core stability and rotation training before and after intervention, and between the control group and the experimental group, in terms of swing speed, ball exit velocity, core muscle capacity and rotation ability. The statistically significant level was determined to be α < 0.05. Results: The control group and the experimental group had significant progress in core stability, dynamic abdominal muscle and dynamic back muscle capacity. There was no significant improvement in the rotation ability of the control group, while the experimental group and the experimental group both improved the swing speed and the ball exit velocity, but did not reach a statistically significant difference. Conclusion: In the core muscle capacity, regardless of the control group or the experimental group is improved, and the improvement of core muscle capacity can also reduce the risk of injury. Both the experimental group and the control group have made progress in both the swing speed and the ball exit velocity. Although there is no significant difference in statistics, the performance of the hitting has improved. Therefore, in the future, if the coach or the player wants to improve the two hitting performance of the swing speed and the ball exit velocity of hitting, the core stability training and the rotation training, such as the medicine rotation training, can be added to the practice, which can help the performance.
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"Caracterização fisica e secagem do acido 2-hidroxibenzoico em leito fluidizado agitado mecanicamente em leito fluidizado pulsado rotativo." Tese, Biblioteca Digital da Unicamp, 2003. http://libdigi.unicamp.br/document/?code=vtls000300920.
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CHOU, CHUN-CHUAN, and 周淳娟. "To Explore the Feasibility of the Position Deviation Conversion between Rotation Axis and Translational Axis in Cone-Beam Computerized Tomography for Breast Cancer Patients." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/snahm8.
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碩士中臺科技大學
醫學影像暨放射科學系暨研究所
107
According to the formula in converting the rotation axis and translation axis into the translation axis, the data from the cone-beam computed tomography (CBCT) of the breast cancer patient is retrospectively collected. Comparing the difference between the data before and after conversion and explore whether the formula can be directly applied to the patient who received breast cancer radiotherapy (RT) on the treatment couch lack of the rotation axis correction function. The CBCT data before RT for breast cancer patients were collected from January 1, 2015 to December 31, 2017. A formula published by B Sarkar et al. in March 2018 that converted the rotation axis and translation axis deviation values to the translation axis deviation values. According to the results of the data conversion, the average value of each axis in three dimensions is calculated separately, and the data difference before and after the conversion is checked using the Paired samples t-test. The CBCT values of 121 patients receiving breast RT in the X, Y, and Z axes were: -0.36±4.10, 1.60±2.92, and -1.10±2.73, in millimeter, respectively. The mean and p values before and after the three-dimensional transformation were obtained according to the conversion formula as follows: -0.38 vs 1.15, p<0.001, 1.52 vs -0.14, p <0.001, -1.11 vs 0.03, p <0.001, in mm. Dr. B Sarkars formula provided a way for the treatment couch achieve better displacement correction through the new displacement deviation values. In our study, the results are significantly different from the translational axis deviation values found in the clinical patients. It is shown that this conversion formula can not be applied to CBCT data for breast cancer patients on the treatment couch which cannot perform rotation axis correction. Further analysis and discussion in more rigorous conditions are needed.