Dissertations / Theses on the topic 'Curve radius'

Sprinting on a curve is significantly slower than on a straightaway. Although the dimensions vary from track to track, indoor track curves are among the tightest curves that athletes will sprint at maximal speed. Previous studies have provided theories for how speed attenuation occurs when running on a curve. Yet, no previous research has determined how the variability of indoor track curve radii affects trained sprinters at maximal speeds. Purpose: To determine the differences in running speeds, ground time (GT), and medio-lateral (ML) impulse, with different indoor track radii. A secondary purpose was to understand the between-leg differences in GT and ML impulse during maximal sprinting on a curve. Methods: 10 male intercollegiate sprinters performed 45-m maximal sprints on a straightaway, 15-m track curve and 21-m track curve. A force platform embedded under an indoor track surface measured ground reaction forces while timing lights measured running speed. Analysis: A mixed models analysis of variance blocking on subjects was performed testing the main effects of the track curve on sprinting speed, GT and ML impulse (p<0.01). Results: Sprinting speed was significantly slower when running on a curve. GT increased for inside leg on both curved path conditions compared to straight. ML impulses increased as the radius of the track curve decreased. Discussion: If a 200m race were performed on both our track curves, the track with 21m curve would be 0.12s faster than the track with the 15m curve. GT and ML impulse results support leading explanations that the inside leg is the limiting factor during curve running. Tighter track curves require greater ML forces, but for a shorter period of time compared to larger track turns. Coaches and athletes should consider the radius of the track curve as they prepare for training and performance and consider injury risk. The speed differences observed due to the track curve radius may provide the first step to understanding how the radius of the indoor track curve affects sprinting speed and ultimately, performance.

Diploma thesis describes and researches some proposed ČSN 73 6101 elements for road design and their subsequent comparison with Norma de Traçado that is main law for road design in Portugal. In practical part, the speed of vehicles during moving on direction curves is researched and subsequently coherence of theoretical assumptions with real speeds is compared. The main aim of this work is to verify the assumption that design speed does not correspond to the real speed that drivers move on road structures.

These days most of the research related to autonomous vehicle technology focuses on vehicle technology itself and lesser on road infrastructure, including geometric design. This research project aims to lower the deficiency of research works required to make the optimized geometric road design for autonomous vehicle sustainable. In geometric design, significant concerns are designing the road geometrics such as lane width, the radius of horizontal curves, sag vertical curves and crest vertical curves, extra widening, setback distance, and intersection, making the road safer for the vehicles to travel comfortably.Road geometrics is widely designed using the stopping sight distance model, which provides sufficient time to avoid accidents and is efficient. Here in the research work, the stopping sight design model is used for autonomous vehicle technology. At first, the art of autonomous vehicle technology is studied, and a significant difference between autonomous vehicle technology and human-driven vehicle to apply stopping sight distance model is figured out. A literature study is also done for the geometric design of the road for the vehicle with the human driver and autonomous vehicle. The AASHTO model derived for the human-driven vehicle is used and modified for the autonomous vehicle, which gives the optimized geometric design for the autonomous vehicle. The Optimized geometric design parameter is designed individually in AutoCAD Civil 3D. Two road designs follow this in a random rural topography consisting of a normal road design for the vehicle with the human driver and a fully autonomous vehicle. Finally, the sustainability of optimized geometric design compared to road design for the human-driven vehicle is checked in terms of earthwork, pavement surface areas, and pavement materials volume. The result shows that the optimization of a geometric road design for autonomous vehicles is sustainable and extensive research is required.

The master‘s thesis focuses on the optimization of the design values of curves of the horizontal alignments of the roads. It deals with the comparison of values between czech and foreign standards and differences between them. The practical part examines the values of the real speeds of vehicles passing through the curves of various parameters that were measured during measurements of selected curves during 2014. From these data a new design values are derived that could be used for the design of horizontal alignments.

In this research, Acoustography Nondestructive Evaluation method was investigated for inspecting “tight radii” in carbon fiber reinforced polymer (CFRP) components. Ultrasonic inspection of tight radii is challenging because of refraction and/or mode conversion of ultrasound waves at the entry and exiting surfaces of the tight radii. Snell’s law was used to first study the refraction and/or mode conversion behavior of the ultrasound beam at the entry and exiting surfaces of a CFRP panel; to help establish the angular range over which ultrasound is transmitted through CFRP material. Snell’s law data was then used as a guide for setting up the Acoustography system and part orientation to optimize inspection of several real-world CFRP components containing tight radii. CFRP tight-radii specimens were prepared by strategically placing markers around the tight radius of each specimen to ensure full coverage of the tight radius region. Acoustography inspection was first performed with a straight beam to establish limitation of the straight beam in detecting markers in the tight-radii region, as predicted by Snell’s law. Acoustography inspection was then performed using a multi-angle beam (+/- 12.5o) to improve detection of markers in the tight-radii region. Results confirmed that straight beam (flat transducer) could not penetrate the sample at the start of the tight radius because of refraction or mode conversion effects. However, the use of multi-angle beam (multi-angle transducer) greatly improved the penetration through the tight radius because some of beam angles were within the ultrasound transmission range for the tight radii. Experiments were also performed by changing orientation of the CFRP sample under the multi-angle or straight beam. Sample orientation was changed at five-degree increments so that optimum conditions for the tight-radii inspection could be determined. This research provides a basis on which further improvements can be made to advance the Acoustography NDE method for the inspection of tight radii in CFRP components.

The uniform thickness of knots has been used to investigate knotted polymers and DNA strands. Even though these structures carry great length, it is unusual for them to contain knots. However, when they do, it can cause gene malfunctions. In fact, scientist have demonstrated that knotting may cause a loss of genetic material by blocking DNA replication and also blocking transcription of a gene into its active protein. Since it is possible for biological structures, such as polymers and DNA strands, to exhibit forces or charges of different strengths the idea of a non uniform thickness of a knot is explored. In his work, O. Durumeric provides a definition for the non uniform thickness. This thesis will provide an alternative characterization for the non uniform thickness of a knot, which is more conducive to computer calculations.

This Ph.D. Thesis has as general subject the study of extrasolar planets using the radial velocity technique from both, instrumental and observative, points of view. Two main parts compose the work: the upgrade of the spectrograph FOCES, a high resolution spectrograph that will be installed next year at the Wendelstein Observatory, and the search of giant planets around stars in the open cluster Messier-67 (M67).
Die vorliegende Dissertation behandelt die Suche von extra-solaren Planeten mit der Radialgeschwindigkeits Methode und zwar sowohl in Bezug auf die dafür notwendige Instrumentierung als auch auf die Beobachtung. Die Arbeit ist in zwei Teile gegliedert. Im ersten Teil werden die vorgenommenen Verbesserungen des hochauflösenden Spektrographen FOCES beschrieben, der im kommenden Jahr am Wendelstein Observatorium installiert werden wird. Der zweite Teil handelt von der Suche nach Gasplaneten im offenen Sternhaufen M67.

In this dissertation, the aim is to investigate the empirical relationship between the partial pressure of CO2 (pCO2) and other ocean variables in the Southern Ocean, by using a small percentage of the available data. CO2 is one of the main greenhouse gases that contributes to global warming and climate change. The concentration of anthropogenic CO2 in the atmosphere, however, would have been much higher if some of it was not absorbed by oceanic and terrestrial sinks. The oceans absorb and release CO2 from and to the atmosphere. Large regions in the Southern Ocean are expected to be a CO2 sink. However, the measurements of CO2 concentrations in the ocean are sparse in the Southern Ocean, and accurate values for the sinks and sources cannot be determined. In addition, it is difficult to develop accurate oceanic and ocean-atmosphere models of the Southern Ocean with the sparse observations of CO2 concentrations in this part of the ocean. In this dissertation classical techniques are investigated to determine the empirical relationship between pCO2 and other oceanic variables using in situ measurements. Additionally, sampling techniques are investigated in order to make a judicious selection of a small percentage of the total available data points in order to develop an accurate empirical relationship. Data from the SANAE49 cruise stretching between Antarctica and Cape Town are used in this dissertation. The complete data set contains 6103 data points. The maximum pCO2 value in this stretch is 436.0 μatm, the minimum is 251.2 μatm and the mean is 360.2 μatm. An empirical relationship is investigated between pCO2 and the variables Temperature (T), chlorophyll-a concentration (Chl), Mixed Layer Depth (MLD) and latitude (Lat). The methods are repeated with latitude included and excluded as variable respectively. D-optimal sampling is used to select a small percentage of the available data for determining the empirical relationship. Least squares optimization is used as one method to determine the empirical relationship. For 200 D-optimally sampled points, the pCO2 prediction with the fourth order equation yields a Root Mean Square (RMS) error of 15.39 μatm (on the estimation of pCO2) with latitude excluded as variable and a RMS error of 8.797 μatm with latitude included as variable. Radial basis function (RBF) interpolation is another method that is used to determine the empirical relationship between the variables. The RBF interpolation with 200 D-optimally sampled points yields a RMS error of 9.617 μatm with latitude excluded as variable and a RMS error of 6.716 μatm with latitude included as variable. Optimal scaling is applied to the variables in the RBF interpolation, yielding a RMS error of 9.012 μatm with latitude excluded as variable and a RMS error of 4.065 μatm with latitude included as variable for 200 D-optimally sampled points.
Thesis (MSc (Applied Mathematics))--North-West University, Potchefstroom Campus, 2012

The Growth Curve Model is a bilinear statistical model which can be used to analyse several groups of repeated measurements. Normally the Growth Curve Model is defined in such a way that the permitted sampling frequency of the repeated measurement is limited by the number of observed individuals in the data set.In this thesis, we examine the possibilities of utilizing highly frequently sampled measurements to increase classification accuracy for real world data. That is, we look at the case where the regular Growth Curve Model is not defined due to the relationship between the sampling frequency and the number of observed individuals. When working with this high frequency data, we develop a new method of basis selection for the regression analysis which yields what we call a Bilinear Gaussian Radial Basis Function Network (BGRBFN), which we then compare to more conventional polynomial and trigonometrical functional bases. Finally, we examine if Tikhonov regularization can be used to further increase the classification accuracy in the high frequency data case.Our findings suggest that the BGRBFN performs better than the conventional methods in both classification accuracy and functional approximability. The results also suggest that both high frequency data and furthermore Tikhonov regularization can be used to increase classification accuracy.

Als Stand der Technik sind einfache, kreisförmige Verrundungen zur Reduktion von Kerbspannungen an Querschnittsübergängen bekannt, für die aus Tabellenwerken / Diagrammen in der Literatur die Formzahl einfach abgelesen werden kann. Die Effizienz der Spannungsreduktion solcher Lösungen ist jedoch sehr begrenzt. Ziel der Arbeit ist es daher, dem Konstrukteur bzw. Berechnungsingenieur ein Verfahren in die Hand zu geben, mit dem er für Standardquerschnittsübergänge und Standardlastfälle "Nicht-Kreiskerben" ohne teure und zeitaufwendige FEM-Analyse einfach durch Nutzung geeigneter Formzahldiagramme auslegen kann. Dabei sind sogar Formzahlen von nahezu eins möglich, d.h., in der "Kerbe" bleibt praktisch nur noch die Nennspannung übrig. Die Präsentation ist zweitgeteilt: Im ersten Teil werden die Arbeitsmethoden bzw. Softwarefunktionen und verwendeten Softwarewerkzeuge vorgestellt: Dies sind die Programme Creo Parametric als vollparametrisches CAD-Werkzeug und Creo Simulate als p-FEM-Programm der Parametric Technology Coprporation (PTC). Der zweite Teil der Präsentation beschreibt den Gültigkeitsbereich sowie die untersuchten Kerbgeometrien: Die einfache kreisförmige Verrundung als Stand der Technik, die Zwei-Radien-Kerbe, die Baud-Kurve, die Methode der Zugdreiecke nach Claus Mattheck, die elliptische Kerbe sowie die konische Rundung als generalisierte elliptische Kerbe. Es wird kurz eine Bibliothek vorgestellt, mit der solche Kerben einfach ausgelegt werden können, d.h. Ihre exakte Geometrie festgelegt sowie die zugehörige Formzahl αk bestimmt werden kann
Circular (one-radius) fillets are known as state-of-the-art for reducing notch stresses at cross section transitions. The stress concentration factor Kt of such geometries can be read out from diagrams/tables given in the literature. However, the efficiency of stress reduction of circular notches is very limited. The goal of the work therefor is to present a method for the designer/analyst how to design non-circular notches/fillets just by using suitable Kt-diagrams without time-consuming and expensive FEM analyses. Kt-numbers of nearly one are possible, that means in the "notch" just the nominal stress appears and no stress concentration takes place. The presentation has two parts: Part one describes the working methods and software functions as well as software tools: Creo Parametric as fully-parametric CAD program and Creo Simulate as embedded p-FEM-tool from Parametric Technology Corporation (PTC) have been used. The second part describes the range of validity and the examined notch geometries: The one-radius fillet as state-of-the-art, the two-radii filet, the Baud-curve, the method of tensile triangles from Claus Mattheck, the standard elliptical fillet and the conical round as generalized elliptical fillet. A notch layout library is shortly presented that allows to design such fillets, that means exactly determine the notch geometry and the related stress concentration factor Kt

The subject matter of this theses is a static design and appraisal of a structure of the planetarium roof. It is a cupola over the circular plan and consists of two radial arched ribs. This theses contains two varieties of its structure.

Le mémoire traite de la machine à réluctance variable en proposant d'une manière simultanée et du point de vue conception des solutions à ses deux inconvénients majeurs à savoir les ondulations de couple et les efforts radiaux. Les premières se propagent le long de la chaine de transmission diminuant ainsi le confort des usagers et les deuxièmes sont à l’origine d’une nuisance sonore. Dans une première partie et en s’intéressant à une structure axiale caractérisée par une faible force radiale, un bilan sur cette structure est donc établi. En effet, une configuration à deux stators et un rotor est la plus adéquate pour éventuellement remplacer la machine radiale de référence. Cette structure axiale est comparée à cette machine de référence après avoir établi des règles de passage d’une structure à une autre. Un premier passage est effectué en gardant le même encombrement et un deuxième passage en dimensionnant la machine axiale pour satisfaire le même cahier des charges que la machine radiale. Dans une deuxième partie, le travail s’oriente vers la modification de la structure radiale de la machine de référence et son optimisation. Plusieurs modifications sont proposées dont une structure avec une cale magnétique qui est la plus performante. Des optimisations géométriques à l’aide de l’algorithme génétique sur un point de fonctionnement sont ensuite effectuées pour remédier aux deux problèmes. A la fin, un récapitulatif de plusieurs structures optimisées est proposé pour servir de référence. Le choix de la machine la plus adéquate pourra donc être effectué en faisant un compromis entre la maximisation du couple, la réduction de ses ondulations et la réduction des efforts radiaux
This report deals with switched reluctance motor by offering design solutions to the drawbacks of torque ripples and radial forces in the same time. Torque ripples reduce the user comfort and radial forces are the origin of noise. In the first part, an axial structure characterized by low radial force is analysed. Indeed, an axial configuration with two stators and one rotor is the most appropriate to replace the reference radial machine. Ones the rules of passage from one structure to another are established, the axial structure is then compared to the reference one. A first passage is made by keeping the same volume and a second one by sizing the axial machine with the same specifications as the radial one. In the second part, the work concerns the modification of radial structure of the reference machine and its optimization. Several modifications are proposed including a structure with a magnetic wedge which is the most efficient. Geometric optimization using genetic algorithm are then performed on operating points to remedy the both problems. In the end, several optimized structures are proposed. The choice of the most suitable machine can be done by making a compromise between the torque maximization, reducing its ripples and reducing radial forces

La chromatographie membranaire est une alternative à la chromatographie classique sur résine basée sur le transport convectif des solutés à travers une membrane microporeuse plutôt que par le transport diffusif des solutés dans les particules de résines. Cette technique présente les avantages de diminuer les phénomènes de diffusion, de réduire les temps de séjour et les pertes de charge, et de permettre la purification rapide de quantités importantes de molécules. La chromatographie membranaire connaît un fort succès commercial. Une gamme importante de membranes chromatographiques mettant en jeu différents mécanismes de rétention (échange d’ions, affinité, etc.) et différentes géométries (feuille, spirale, etc.) est actuellement commercialisée. Malgré ce succès, différents aspects relatifs à la chromatographie membranaire restent mal connus. Cette thèse de doctorat se propose de répondre à certaines questions relatives à cette technique
Membrane chromatography (MC) is an alternative to traditional resin packed columns chromatography. The solute mass transport in the membrane occurs in convective through-pores rather than in stagnant fluid inside the pores of the resins particles, which is limited by the slow diffusive transport. MC offers the main advantage of reducing diffusion phenomena, shorter residence time and lowered pressures drops, and thus, facilitates rapid purification of large quantities of molecules. A wide range of chromatographic membranes involving different molecules retention mechanisms (ion exchange, affinity, etc...) is now commercialized. Despite their success, the influence of the geometry of the membrane chromatography devices remains relatively unexplored from a theoretical point of view. This doctoral thesis is aimed to clarify some ambiguous points related to this technique

Pour une courbe, la courbure est une grandeur géométrique déterminante pour sa forme. Dans de nombreuses applications de la CAO (automobile, aéronautique), les courbes que l'on cherche à modéliser doivent être à courbure monotone, dans le but d'obtenir des formes aérodynamiques et esthétiques. Dans ce travail, nous apportons des solutions via les courbes polynomiales cubiques et rationnelles quadratiques (arcs coniques) quisont controlées par un ensemble de points (et de masses dans le cas rationnel)
For a curve, the curvature is a deciding geometric feature for its shape. For some applications of CAD (automotive, aeronautics), it is important to maintain monotone curvature along the curve we aim to modelize in order to obtain aerodynamic and aesthetic shapes. In this work, solutions are given via the cubic polynomial curves and the quadratic rational curves (conic segments) which are controlled by a set of points (and weights in the rational case)

Губар, О. В. Обґрунтування норм улаштування та утримання колії для кривих з радіусами менше 350 метрів : авт. дис. к. т. н.: 05.22.06 / О. В. Губар ; Дніпропетр. нац. ун-т залізн. трансп. ім. акад. В. Лазаряна. - Д., 2011.
UA: АНОТАЦІЯ. Дисертація присвячена обґрунтуванню норм улаштування та утримання колії для кривих з радіусами менше 350 м шляхом впровадження конструкції рейкових скріплень з можливістю складання та регулювання ширини колії у як в межах кругових, так і перехідних кривих для типових залізобетонних шпал. Розроблено математичну модель взаємодії рухомого складу і колії та програмне забезпечення, які дозволили в дисертації встановити раціональні обґрунтовані норми ширини колії та розробити технологію складання колії з залізобетонними шпалами. Надано методики суцільного і локального регулювання ширини колії зі скріпленням СКД65-Б. Отримані теоретичні й практичні результати використано в розробці конструкції колії на залізобетонних шпалах для кривих ділянок радіусом менше 350 м.
RU: АННОТАЦИЯ. Диссертация посвящена обоснованию норм устройства и содержания пути для кривых с радиусами менее 350 м путем внедрения конструкции рельсовых скреплений с возможностью устройства и регулирования ширины колеи как в пределах круговых, так и переходных кривых для типовых железобетонных шпал. Выполнен анализ материалов расследования сходов подвижного состава. Установлено, что основная часть сходов имеет место на станциях в кривых с радиусом менее 350 м при выполнении маневровых работ. В большинстве случаев сходили с рельсов локомотивы с трехосными тележками. Существующие на сегодня нормы ширины пути в кривых участках рассчитанны исходя из условий вписывания жесткой базы массового железнодорожного экипажа. Расчеты обоснования этих норм разрабатывались с учетом наличия, на то время, в вагонном парке длиннобазных двухосных вагонов и грузовых вагонов с трехосными тележками. При массовом внедрении железобетонных шпал норма ширины колеи на прямых и кривых при радиусе 300 м и больше на железобетонных шпалах установлена одинаковой, равной 1520 мм. Область применения железобетонных шпал ограничена величиной радиуса из-за необходимости обязательного расширения ширины колеи в кривых участках меньших радиусов. На сегодняшний день как на железных дорогах Украины, так и стран СНГ отсутствуют обоснованные нормы устройства пути на железобетонных шпалах в кривых участках пути с радиусами круговых кривых менее 350 м. Такие обоснования отсутствуют, в первую очередь, из-за того, что отсутствуют конструкции пути, которые отвечали бы требованиям для таких кривых, а именно возможностью устройства пути с заданной и обоснованной шириной колеи в пределах круговой кривой и обеспечения отвода расширения в пределах переходных кривых. Кроме того, такая конструкция должна предусматривать возможность регулирования ширины колеи, которая изменяется в процессе эксплуатации. Вопросом возможности внедрения железобетонных шпал в кривых участках с радиусами менее 350 м непрерывно занимались еще с 70-тых годов прошлого столетия. Как результат – в круговых кривых с радиусами от 200 м до 450 м было разрешено укладывать специальные железобетонные шпалы (типа Ш-6) с нормой ширины колеи 1535 мм, но опыт их эксплуатации оказался достаточно неудачным, из-за отсутствия как возможности регулирования ширины колеи, так и отсутствия возможности создания отвода ширины колеи в пределах переходных кривых. Автором разработана конструкция рельсовых скреплений для типовых железобетонных шпал (Ш-1, Ш-6), что дает возможность устройства и регулирования ширины колеи в кривых участках любого радиуса как в пределах круговых, так и переходных кривых. Эта конструкция прошла опытную эксплуатацию на сети железных дорог Украины и введена в постоянную эксплуатацию приказом Государственной администрации железных дорог Украины. В настоящее время при отсутствии длиннобазных двухосных вагонов и вагонов с трехосными тележками в вагонном парке и наличием разработанной автором конструкции, что позволяет собрать путь с шириной колеи до 1535 мм (1540 мм со шпалами типа Ш-6) появилась техническая возможность установления и регулирования ширины колеи в кривых, где необходимое ее расширение. Это вызывает необходимость обоснования норм устройства и содержания колеи для кривых с радиусами менее 350 м. О необходимости таких норм для железобетонных шпал в кривых участках пути с радиусами кривых менее 350 м свидетельствует количество деревянных шпал, уложенных в путь и которые могут быть заменены на железобетонные шпалы. Например, на Львовской железной дороге уложено 4 млн. 554 тыс. деревянных шпал что составляет 48 процентов от общего количества шпал, а на остальных железных дорогах доля деревянных шпал составляет от 22 до 30 % от их общего количества. Больше всего деревянных шпал имеют так называемые горные дистанции, где много кривых радиусом менее 350 м. Кроме того, фактический срок службы железобетонных шпал отвечает расчетному и складывает около 40 лет, а фактический срок службы деревянных шпал составляет около 7–7,5 лет, что в 2–2,5 раза меньше от расчетного. Основная причина сокращения срока службы связана с механическими повреждениями древесины в результате частых перешивок рельсовых нитей. По этой причине 33 процента деревянных шпал непригодны для дальнейшего использования. Кроме того, закупки деревянных шпал ограничены малым объемом предложений от поставщиков, из-за чего шпал катастрофически не хватает не только для проведения плановых, но и текущих ремонтов. Разработана математическая модель взаимодействия подвижного состава и пути и программное обеспечение, которые позволили в диссертации установить рациональные обоснованные нормы ширины пути и разработать технологию устройства и содержания пути с железобетонными шпалами. Полученные теоретические и практические результаты использованы в разработке конструкции пути на железобетонных шпалах для кривых участков радиусом менее 350 м и использованы в нормативно-техническом документе Укрзализныци «Инструкция по устройству и текущему содержанию пути со скреплениями типа СКД65» ЦП-0199.
EN: ANNOTATION. The present thesis grounds the standards of conformation and maintenance of track for curves with radiuses less than 350 m by introducing the rail clips device with the option of setting railway gauge within the ambit of both circular and transition curves for typical concrete ties. The mathematical model of interaction of rolling stock and track and the software that allowed setting properly grounded standards of railway gauge and developing the technology of conformation and maintenance of track with concrete ties are worked out in the thesis. Methods of general and local adjustment of railway gauge with the help of СКД65-Б rail clip are given. Theoretical and practical educts were used in the development of conformation of track with concrete ties for curves with radiuses less than 350 m.

Calculs scf et ci des courbes de potentiel du systeme s+h**(+) dans les symetriplets pi et delta internenant dans la reaction, avec des orbitales moleculaires occupees representees par des orbitales atomiques polarisees et des orbitales moleculaires virtuelles donnees par la projection d'orbitales atomiques orthogonalement aux orbitales occupees. Traitement de la dynamique de l'echange de charge dans une representation diabatique ou les couplages radiaux sont nuls et l'echange de charge est induit par des couplages de type electronique. Construction d'une representation effective de dimension reduite au nombre des voies ouvertes; calcul des couplages radiaux. Resolution des equations de collision par un traitement quantique dans chaque symetrie; deduction de la constante de vitesse

This thesis is a study into the response and seismic safety of three-dimensional multi-storey concrete structures under concurrent orthogonal seismic excitations. It employs the nonlinear time-history method as its analysis tools. Time-history analyses rely heavily on their utilised earthquake records. Accordingly, this study examines the different approaches of selecting earthquake suites and develops a methodology of selecting representative earthquake scenarios. This methodology is credibly implemented in selecting a far- and a near field suites representative of the New Zealand seismic hazard. The study investigates the response of 6-, 9- and 12-storey concrete structures of different n-X-bays × m-Y-bays. Bidirectional responses of these considered structures are examined and consequently the current combination rules are scrutinised. Consequently this study strongly recommends the use of the 40-percent combination rule in lieu of the widely used 30-percent rule; and the use of time-history analysis in lieu of quasi/equivalent static and response modal analysis methods to avoid their strong dependence on combination rules. An intensive study is conducted employing the incremental dynamic analysis (IDA) technique to investigate structural demands of interstorey drifts, lateral storey drifts and storey accelerations. The study utilises the developed far-field suite and identifies the 50th and 90th percentile demands. Hence it provides easy-to-use expressions to facilitate rapid calculation of the structural demands and the effects of biaxial interactions. An implementation into the Demand and Capacity Factor Design (DCFD) format is presented that infers confidence in the performance levels of the considered structures. The study also draws attention to the importance of considering storey accelerations as their storey values reach as high as 10 × PGA. A sensitivity study is conducted by repeating the IDA investigation while using the developed near-field suite. Subsequently a comparison between the near- and the far-field results is conducted. The results were markedly similar albeit of less magnitudes until the (seismic hazard) intensity measure IM = Sa(T₁) = 0.4g when the near-field results show sudden flat large increase in demands suggesting a brittle collapse. This is attributed to the higher content of the higher mode frequencies contained in near-field ground motions. Finally, the study examines the (vectorial) radial horizontal shear demands in columns and beam-column joints of the previous far- and near-field studies. The combined radial shear demands in corner, edge and internal columns and joints are evaluated that roughly show a square-root proportional relationship with IM that exhibit somewhat brittle failure at IM ≥ 0.35g. Shears demands in the (4-way) internal columns and the (2-way) corner joints show highest magnitude in their respective class. The results suggest transverse joint shear reinforcement of 1.5, 1.0 and 0.5 of the longitudinal reinforcement of the neighbouring beam respectively for corner, edge and internal joints. An implementation of a proposed practical (and simpler) DCFD format shows satisfactory confidence in columns performance in shear up to IM = 0.35g, conversely to joints unsatisfactory performance in shear at the onset of inelastic behaviour (IM > 0.05g).

 The purpose of this project was to prove or disprove the hypothesis that wheel and rail wear, and incidents of wheel squeal increase with increasing bogie rotation friction, while decreasing bogie rotation friction leads to increased incidents of hunting and increased wheel and rail wear. Therefore for any given combination of factors (vehicle type, curve radius, wheel profile, etc) an optimal bogie rotation friction level should exist at which incidents of hunting and wheel squeal are eliminated and wheel and rail wear is minimised. 

In order to test the hypothesis a literature review was first undertaken. The purpose of the review was to examine the results from previous similar projects and identify any areas that may be improved upon in order to achieve the most accurate results. As a result of the literature review the simulation vehicle model was designed. Past studies featured a three-dimensional wagon body with the centre bowl connection modelled as a single spring, or the centre bowl was modelled in isolation. However for this project the vehicle included a centre bowl connection modelled using centre plate springs evenly distributed across the top centre, and plate and rim friction on the centre bowl, radial bumpstops around the rim and a vertical restraint from the cotter pin. Additional features of the simulation vehicle model were friction wedges, in order to properly represent the damping present at the spring nest connection, and a non -circular top centre, to reflect the design currently used by QR (Queensland Rail). 

The remainder of the project focussed on computer simulations of the vehicle model using different combinations of parameters (vehicle type, curve radius, wheel profile, centre bowl friction and loading condition) to examine the way that the vehicle behaviour responded. The vehicle response was determined by measuring the wheelset lateral position, wheelset angle of attack and wear index (calculated using creep force and creepage). 

The first series of simulations were used to prove that the centre bowl friction levels could be determined using wayside monitoring equipment provided that particular conditions were met. Provided that the vehicle was travelling through an area of constant curvature (not in transition or tangent), in 75% of cases the centre bowl friction level to lateral position relationship was relatively linear. Therefore after initial studies to calibrate the system according to the curve radius and type of vehicle it would be possible to calculate the centre bowl friction using wayside monitoring equipment. However if the system was limited to curves with a radius larger than 800m, the accuracy of the system increased to 83% of cases following a linear relationship.   

碩士
中原大學
資訊工程研究所
83
Offsetting is a geometric operation which expands outline of a given object, it is one important method for applications of computer graphics, computer aided design (CAD), and image processing. In this paper, we firstly describe mathematic and differential properties of variable radius offset curve,and we also state the difficulty of constructing offset radius function for the design of variable radius offset curves in computer graphic applications. In order to design variable offset curve effectively and friendly, we present one method to slove the problem, via moving the control points of cubic Bzier curve to generate the radius offset funtion. The algorithm will be discussed for further analysis. Furthermore, we provide a method to directly manipulate the interior points of variable radius offset curves. By point to point,we can manipulate shape of variable radius offset curves freely. The advantages of conventional interpolation mathods are also kept in the method.

碩士
東吳大學
資訊科學系
93
Informally, a geometric constraint problem consists of a (finite) set of geometric objects and a (finite) set of constraints between them. The geometric objects are drawn from a fixed universe such as point, lines, circles and conics in the plane. The constraints are logical constraints such as incidence, tangency, perpendicularity, etc., or metric constraints such as distance or angle. There are two problems we want to solve in this work. The first problem is to find the variable radius circle tangents to 3 geometric objects, such as point, line, circle, and Bezier curve. The second problem is to solve the cluster merge problem whose geometric objects are point, circle, line, and Bezier Curve. For solving first problem, the cyclographic for the geometric objects (points, circle, line, and Bezier curve) has to be surveyed. Based on the fact that the cyclographic maps of Bezier curve have no implicit form, the approximation for the maps should be constructed. After we construct the cyclographic maps for 3 geometric objects, and find their intersection points (x,y,z), we find the variable radius circle centered at (x,y) with radius z, tangent to those 3 geometric objects. For the second problem, we extend the cluster merge problem to the problem containing Bezier curve as the basic geometric objects. There are two constraints between the variable radius circle and each of the rigid geometric objects. We find the intersection points for 2 fixed geometric objects and 2 translational/rotational geometric objects. Next, we convert the voxel location (in volume space) back to point location (in geometric space). Finally we refine the variable radius circle centered at (x,y) with radius z, tangent to each of the rigid geometric objects.

M.Ing.
Sound pressure levels exceeding acceptable limits are being generated by trains travelling on the 1000 m radius curved railway line past the town of Elands Bay. Unacceptable sound levels are attributed mainly to top of rail wheel squeal. Top of rail wheel squeal belongs to the family of selfinduced vibrations and originates from frictional instability in curves between the wheel and the rail under predominantly saturated lateral creep conditions. In small radius curves, saturated lateral creep conditions occur due to the steering of railway wheelsets with large angles of attack. Given the large curve radius and the utilisation of self-steering bogies on the Sishen-Saldanha Iron Ore railway line, curve squeal is a highly unexpected result for the 1000 m radius curved railway line. This is because curving of bogies in large radius curves are achieved without high wheelset angles of attack leading to saturated creep conditions. An experimental and analytical investigation was carried out to identify the mechanisms influencing the generation of wheel squeal in large radius curves. Simultaneous measurement of sound pressure and lateral wheel-rail forces were made during regular train service in one of the two 1000 m radius curves at Elands Bay to characterise the bogie curving behaviour for tonal noise due to wheel squeal occurring in the large radius curve. The lateral force curving signature not only reveals the levels of lateral wheel-rail forces required for bogie curving, but also whether the bogie is curving by means of the creep forces generated at the wheel-rail interface only or if contact is necessitated between the wheel flange and rail gauge corner to help steer the bogie around the curve. The test set-up consisted of two free field microphones radially aligned at equivalent distances towards the in – and outside of the curve in line with a set a strain gauge bridges configured and calibrated to measure the lateral and vertical forces on the inner and outer rail of the curve. This test set-up allowed the squealing wheel to be identified from the magnitude difference of the sound pressures recorded by the inner and outer microphones in combination with comparing the point of frequency shift of the squeal event due to the Doppler Effect with the force signals of the radially aligned strain gauge bridges. From the experimental phase of the investigation, it was found that wheel squeal occurring in the 1000 m radius curve at Elands Bay is characteristic of empty wagons and is strongly related to the squealing wheel’s flange/flange throat being in contact with the gauge corner of the rail. Here high levels of spin creepage associated with high contact angles in the gauge corner lead to high levels of associated lateral creepage necessary for squeal generation. This is in contrast to lateral creepage due to high wheelset angles of attack being the key kinematic parameter influencing squeal generation in small radius curves. Furthermore, the amplitude of wheel squeal originating from the passing of empty wagons was found to be inversely proportional to the level of flange rubbing on the squealing wheel i.e. increased flange contact on the squealing wheel brings about a positive effect on squeal control. Contrary to the empty wagons which are characterised by tonal curve squeal, loaded 4 wagons requiring contact between the wheel flange and rail gauge corner in the 1000 m curve was characterised by broadband flanging noise. It was concluded from measurements that flange contact occurring under high lateral forces for steady state curving of loaded wagons provides the complete damping necessary for squeal control. The curve squeal noise that originated from the passing of empty wagons in the Elands Bay curve could further be classified according to the frequency at which the squeal event manifested itself in the curve, i.e. low frequency audible (0 – 10 kHz), high frequency audible (10 – 20 kHz) and ultrasonic squeal (> 20 kHz). The vast majority of low frequency audible squeal events recorded in the 1000 m Elands Bay curve occurred at approximately 4 kHz and originated from the low rail/trailing inner wheel interface, whilst the vast majority of high frequency audible squeal events occurred in the frequency range between 15 and 20 kHz and originated from both the high rail/leading outer wheel and low rail/trailing inner wheel interfaces.

This thesis documents the linear mixed model developed for vehicle speed along two-lane two-way rural horizontal curves in the outside lane. Speed data at each curve was collected at four points along the curve including the midpoint of the curve for a minimum of 48 hours during weekdays. Vehicle speed was analyzed separately for day and night conditions. The horizontal curves were categorized into different groups using different methods using side friction demand, radius and pavement edgeline marking retroreflectivity. In the speed prediction model, radius, superelevation at the midpoint of the curve, deflection angle, posted speed limit and pavement edgeline marking retroreflectivity were used to predict the vehicle speed at the midpoint of the horizontal curve. The regression analysis indicates that all of these variables are statistically significant in predicting the vehicle speed at the midpoint of horizontal curves with a 95 percent confidence interval. The linear model determined that the vehicle speed has a positive relation with the radius of the curve, superelevation and posted speed limit but has a negative relation with the deflection angle and pavement edgeline marking retroreflectivity. Curves were categorized based on side friction demand or radius and retroreflectivity of pavement edgeline marking. ANOVA was used to compare the day and night time speed. The comparisons reveal that vehicle speed at the horizontal curves decreases as the side friction demand value of the curves increases. Another finding of this research was that even though the posted speed limit is incorporated into the calculation of side friction demand, it may be necessary to analyze the impact of posted speed limit on vehicle speed for both daytime and nighttime. Previous literature determined that drivers may drive at an unsafe speed during nighttime at high levels of retroreflectivity. The results of this study could not confirm this statement as data from this study suggests that for curves with pavement edgeline marking retroreflectivity greater than 90 mcd/m2/lx, the effects of retroreflectivity on speed was determined to be minimal. This is based on the finding that the daytime and nighttime speeda were basically the same as the daytime and nighttime speed difference was both statistically and practically insignificant.

碩士
國立臺北科技大學
土木工程系土木與防災碩士班
106
Agricultural farming in Taiwan has always been dominated by paddy fields, which is the main target of irrigation for the irrigation channels. The irrigation channels are spread throughout the planting of rice in Taiwan. If we can understand the rating curve of each channel, it is possible to adjust the flow of each channel to correspond to the amount of water needed for agricultural activities through the water conservancy facilities. Thereby reducing the waste of water resources. Therefore, it is an important goal to investigate the details of each channel. How to effectively and quickly obtain the required measurement data and establish a reliable rating curve in a large number of irrigation channels throughout Taiwan is the goal of this study. However, if the rating curve is to be perfected in the discharge measurement process, it is necessary to measure the flow field distribution under each water level as much as possible to calculate the velocity. Therefore,to construct a complete rating curve, multiple measurements are required to achieve Therefore, this study uses the Radial Basis Function Neural Network (RBFNN) model to train and characterize the parameters of the neural network only with the part of measured data, and the remaining data is used for verification. Very good results were obtained in the verification. The network constructed by this parameter is used to simulate the velocity distribution under each water level condition, and the velocity calculation is performed, and the velocity data construction rating curve calculated by the simulation result is performed, and then comparing with the rating curve established by the original measurement data.

碩士
國立中正大學
機械系
87
The purpose of this paper is to propose a methodology to synthesize a four-bar linkage with a desired coupler curve. In this method, four control points are defined to determine the shape of the desired coupler curve. By employing a radial-basis-function neural network, a coupler curve generator is established to relate the control points to the size of the four-bar linkage. When one of the control points is moved, the shape of the coupler curve will be changed and the corresponding four-bar linkage well be generated. In this paper, four control points of a coupler curve is defined based on the symmetry and divide equally characteristics. Next, according to Grashof’s criterion, the range of the length of links is determined to classify the linkages into several types. In each type, various linkages with different sizes are generated to produce their coupler curves and the corresponding control points. The sizes and the control points form training pairs for the RBF neural network. Finally, the computer program for the RBF neural network is implemented in the PC Window environment by C++ computer language. This paper provides a novel approach for the generation of the coupler curves. Using an RBF neural network as a core, the coupler curve generator is compact and efficient. The results of this paper are beneficial to the dimensional synthesis of linkages.

碩士
大同工學院
電機工程學系
85
This thesis will provide a faster and simpler radial basis function neuralnetwork from an efficient classifier, a variable learning and a gradient algor-ithm. Its advantage is that we know nothing about the system unless its input-output pairs and use less time learning well. The fuzzy-side view will help usfind the character more simply and quickly. The proposed method will further improve the power and/or the speed of the learning of the Neural Network whichis not bounded with smooth system. In examples, we will know that it can be used in the predict problem very well with both stationary and nonstationary time series. In the similar way, we can still use this proposed method in otherinput-output pairs' problem.

This thesis deals with the scientific achievements of the inspirational scientist Marie Curie Sklodowska as well as with the issue of acute iradiation sickness. Two goals were set in the work. The first objective was to map the life and scientific work of Mrs. Curie. The second objective was to describe the causes and consequences of acute illness from radiation. At the beginning the theoretical part describes the life of Marie Curie Sklodowska. Her difficult beginnings at the University of Paris and her great achievements- discovering the elements of polonium and radium. Further, the work deals with acute radiation sickness together with basics of radiobiology. In the practical part, I tried to find an answer to this question. Why Mrs. Curie did not die from acute radiation sickness? I have gained a lot of information by studying literature, professional articles and internet resources. Most of the facts were obtained from foreign professional journals because there are not many sources in the Czech language. Thanks to this information, I could deal with this person more detailed. At the same time, in the case of toxic polonium-210, an estimated fatal dose for adults was calculated. In addition, calculations were made of how much Marie Curie Sklodowska would have to isolate and incorporate in order to die for the consequences of acute radiation sickness. For better clarity, the results are summarized in the tables. Safety precautions and health problems associated with work with radioactive elements would not be neglected. Marie Curie Sklodowska probably was not able to create a clean polonium, and therefore probably did not even accept this direct contact, which would be able to cause her death.

Indiana University-Purdue University Indianapolis (IUPUI)
Nicotine use among individuals with schizophrenia occurs at extremely high rates. The prevailing theory is that individuals with schizophrenia smoke as a form of self-medication to ameliorate sensory and cognitive deficits. However, these individuals also have enhanced rates of addiction to several drugs of abuse and may therefore smoke as a result of enhanced addiction liability. The experiments described herein explored these two hypotheses by assessing the effect that nicotine has on working memory, addiction vulnerability (locomotor sensitization and self-administration), and nicotinic acetylcholine receptor (nAChR) expression as well as the developmental expression of these characteristics in the neonatal ventral hippocampal (NVHL) neurodevelopmental animal model of schizophrenia. The results from these studies indicate that NVHLs had working memory impairments in both adolescence and adulthood, with nicotine having a negligible effect. Additionally, NVHLs displayed enhanced locomotor sensitization to nicotine which emerged in adulthood as well as an enhanced acquisition of nicotine self-administration, administering more nicotine overall. These behavioral differences cannot be attributed to nAChR expression as nicotine upregulated nAChR to a similar extent between NVHL and SHAM control animals. These data indicate that the enhanced rates of nicotine use among individuals with schizophrenia may occur as a result of an enhanced vulnerability to nicotine addiction.

Heavy oil production depends on the understanding of mechanical and flow properties of unconsolidated or weakly consolidated sands under different loading paths and boundary conditions. Reconstituted bitumen-free Athabasca oil-sands samples were used to investigate the geomechanics of a steam injection process such as the Steam Assisted Gravity Drainage (SAGD). Four stress paths have been studied in this work: triaxial compression, radial extension, pore pressure increase and isotropic compression. Absolute permeability, end-point relative permeability to oil & water (kro and krw), initial water saturation and residual oil saturation were measured while the samples deformed. Triaxial compression is a stress path of increasing mean stress while radial extension and pore pressure increase lead to decreasing mean stress. Pore pressure increase experiments were carried out for three initial states: equal axial and confining stresses, axial stress greater than confining stress and confining stress greater than axial stress. Pore pressure was increased under four boundary conditions: 1) constant axial and confining stress; 2) constant axial stress and zero radial strain; 3) zero axial strain and constant confining stress; and 4) zero axial and radial strain. These experiments were designed to mimic geologic conditions where vertical stress was either S1 or S3, the lateral boundary conditions were either zero strain or constant stress, and the vertical boundary conditions were either zero strain or constant stress. Triaxial compression caused a decrease in permeability as the sample compacted, followed by appreciable permeability enhancement during sample dilation. Radial extension led to sample dilation, shear failure and permeability increase from the beginning. The krw and kro increased by 40% and 15% post-compaction respectively for the samples corresponding to lower depths during triaxial compression. For these samples, residual oil saturation decreased by as much as 40%. For radial extension, the permeability enhancement decreased with depth and ranged from 20% to 50% while the residual oil saturation decreased by up to 55%. For both stress paths, more shear-enhanced permeability was observed for samples tested at lower pressures, implying that permeability enhancement is higher for shallower sands. The pore pressure increase experiments showed an increase of only 0-10% in absolute permeability except when the effective stress became close to zero. This could possibly have occurred due to steady state flow not being reached during absolute permeability measurement. The krw curves generally increased as the pore pressure was increased from 0 psi. The increase ranged from 5% to 44% for the different boundary conditions and differential stresses. The kro curves also showed an increasing trend for most of the cases. The residual oil saturation decreased by 40-60% for samples corresponding to shallow depths while it increased by 0-10% for samples corresponding to greater depths. The reservoirs with high differential stress are more conducive to favorable changes in permeability and residual oil saturation. These results suggested that a decreasing mean stress path is more beneficial for production increase than an increasing mean stress path. The unconsolidated sands are over-consolidated because of previous ice loading which makes the sand matrix stiffer. In this work, it was found that over-consolidation, as expected, decreased the porosity and permeability (40-50%) and increased the Young’s and bulk moduli of the sand. The result is sand which failed at higher than expected stress during triaxial compression. Overall, results show that lab experiments support increased permeability due to steam injection operations in heavy oil, and more importantly, the observed reduction in residual oil saturation implies SAGD induced deformation should improve recovery factors.
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