Dissertations / Theses on the topic 'Three-Body Effects'

The three-dimensionality of the near wake of bluff bodies at high Reynolds numbers is studied experimentally. Measurements were carried out in a 0.9Imx 0.91m wind tunnel (for Re=20000 to 60000) and flow visualisation in a 0.6mx 0.6m water flume (for Re=25(X)). The main purpose is to identify inherent three-dimensional features that may also arise in nominally two-dimensional flows. In order to fix the three-dimensional effects in both time and space, a mild, periodic, geometrical disturbance was imposed on the otherwise two-dimensional geometry of a model with a blunt trailing edge. The trailing edge thus followed a sinusoidal pattern, but a straight edge model was also studied for comparison purposes. Quantitative measurements and flow visualisation revealed that a dual shedding frequency characteristic prevails in the wake of the sinusoidal model. Base drag shows a noticeable drop (in comparison to the straight edge model). Most of the activity seems to happen in the region of the peak, where the dual frequency characteristic is more apparent and also the base drag shows its largest variations. Flow visualisation showed different modes of vortex shedding to exist. Vortical structures in the x- and z- directions were observed for both models. Og vortices are present in the near wake. It is believed that the observed vortices are responsible for the intense base pressure fluctuations and gradients, and also for thin "wisps" appearing between Karman vortices in flow visualisation. A model for the dynamics of the formation region is proposed, by considering the interaction of mean, time-averaged quantities. It is suggested that forming vortices have a tendency to straighten-out. A concept is proposed which links the vortex formation length to other wake parameters, most notably wake width and base pressure. Wake similarity arguments are used in order to explain the shedding frequency variations along the span. The dynamics of vortex dislocations are also discussed. A mechanism is proposed which explains the significance of a characteristic dislocation frequency, fd in the near wake dynamics. It is suggested that fd is a result of the geometrical properties of the vortex filaments and that a link exists between the dislocation frequency and fluctuations in base pressure, vortex strengths and spanwise dislocation position.

In this work the phase behaviour of noble gases is studied comprehensively by different molecular simulation methods using different intermolecular potentials. The aim is to investigate three-body effects on the phase behaviour of noble gases. A true two-body potential model (Barker-Fisher-Watts potential) and the three-body potential model (Axilrod-Teller term) have been used. The results obtained from the two-body BFW potential with the three-body Axilrod-Teller potential included for the vapour-liquid and solid-liquid phase equilibrium properties of pure noble gases are compared with the calculations using the Lennard-Jones potential with different suggested parameter values. The results have been compared with experimental data and the best parameter values for simulating the thermodynamic properties of noble gases are found. Three-body effects on the phase behaviour of noble gases are reported for a large range of density, temperature and pressure. Simple relationships have been found between two-body and three-body potential energies for pure fluids and solids. Three-body effects on the vapour-liquid phase equilibrium properties of argon, krypton, xenon and argon-krypton systems are studied by the Gibbs-Duhem integration Monte Carlo method. Three-body effects on the solid-liquid phase equilibrium properties of argon, krypton and xenon are investigated by non-equilibrium and equilibrium molecular dynamics techniques. All the calculations have been compared with experimental data, which show that three-body interactions play an important role in the overall interatomic interactions of noble gases.

ix, 84 leaves : ill. ; 29 cm Notes Typescript Thesis (M.S.)--University of Oregon, 2003 Includes vita and abstract Includes bibliographical references (leaves 73-84) Another copy on microfilm is located in Archives

The diploma thesis deals with the issue of force effects in the three-point hitch links in the multi-body environment depending on the forces ejected to the plow during the plowing. Through simulations, force responses under the tractor wheels are also identified for various conditions. The work is also analyzed for the impact of the upper link attachment relative to the tractor output parameters.

Les gaz d'atomes ultrafroids offrent des possibilités sans précédent pour la réalisation et la manipulation des systèmes quantiques. Le contrôle exercé sur les interactions entre particules permet d'atteindre le régime de fortes interactions, pour des espèces d'atomes à la fois fermioniques et bosoniques. Dans la limite unitaire, où la force d'interaction est à son maximum, des propriétés universelles émergent. Pour les atomes bosoniques, celles-ci comprennent l'effet Efimov, l'existance surprenante d'une séquence infinie d'états liés à trois corps. Dans cette thèse, nous avons étudiés un système de bosons unitaires. Partant des cas à deux et à trois corps, nous avons montrés que le modèle choisi capturait correctement les caractéristiques universelles de l'effet Efimov. Pour le modèle à N-corps, nous avons développé un algorithme de Monte Carlo quantique capable de réaliser les différentes phases thermodynamiques du système : gaz normal à haute-température, condensat de Bose-Einstein, et liquide d'Efimov. Un unique composant de notre modèle resterait pertinent à la limite de température infinie, à savoir la répulsion corps dur à trois corps, qui constitue une généralisation du potentiel classique entre sphères dures. Pour ce modèle, nous avons proposé une solution au problème d'empilement compact en deux et trois dimensions, fondée sur une Ansatz analytique et sur la technique de recuit simulé. En étendant ces résultats à une situation de pression finie, nous avons montré que le système présente une transition de fusion discontinue, que nous avons identifié à travers la méthode de Monte Carlo
Ultracold atomic gases offer unprecedented possibilities to realize and manipulate quantum systems. The control on interparticle interactions allows to reach the strongly-interacting regime, with both fermionic and bosonic atomic species. In the unitary limit, where the interaction strength is at its maximum, universal properties emerge. For bosonic atoms, these include the Efimov effect, the surprising existence of an infinite sequence of three-body bound states. In this thesis, we have studied a system of unitary bosons. Starting from the two- and three-body cases, we have shown that the chosen model correctly captures the universal features of the Efimov effect. For the corresponding many-body problem, we have developed a quantum Monte Carlo algorithm capable of realizing the different thermodynamic phases in which the system may exist: The high-temperature normal gas, Bose-Einstein condensate, and Efimov liquid. A single ingredient of our model would remain relevant in the infinite-temperature limit, namely the three-body hard-core repulsion, which constitutes a generalization of the classical hard-sphere potential. For this model, we have proposed a solution to the two- and three-dimensional packing problem, based on an analytical ansatz and on the simulated-annealing technique. Extending these results to finite pressure showed that the system has a discontinuous melting transition, which we identified through the Monte Carlo method

Doctor of Philosophy
Department of Physics
Brett D. Esry
The Efimov effect plays a central role in few-body systems at ultracold temperature and has thus accelerated a lot of studies on its manifestation in the collisional stability of the quantum degenerate gases. Near broad Feshbach resonances, Efimov physics has been studied both theoretically and experimentally through the zero-energy scattering observables. We have extended the theoretical studies of Efimov physics to a much broader extent. In particular, we have investigated the three-body Efimov physics near narrow Feshbach resonances and have also identified the Efimov features beyond the zero temperature limit. We have found, near a narrow Feshbach resonance, the non-trivial contribution from both of the resonance width and the short-range physics to the three-body recombination and vibrational dimer relaxation. Remarkably, the collisional stability of the Feshbach molecules are found to be opposite to that near the broad resonances: an increased stability for molecules made by bosons and a decreased stability for those made by fermions. The universal physics observed near the narrow Feshbach resonances is further found not to be limited to the zero temperature observables. We have found that the general features of Efimov physics and those pertaining to a narrow resonance are manifested in different energy ranges above zero temperature. This opens the opportunity to observe Efimov physics by changing the collisional energy while keeping the atomic interaction fixed. The landscape of the universal Efimov physics is thus delineated in both of the interaction and the energy domain. We have also investigated Efimov physics in heteronuclear four-body systems where the complexity can be reduced by approximations. In particular, we have proposed ways for controllable production of the Efimov tri-atomic molecules by three-body or four-body recombinations involving four atoms. We have also confirmed the existence of four-body Efimov effect in a system of three heavy particles and one light particle, which has resolved a decade-long controversy on this topic. Finally, we have studied the collisional properties of four identical bosons in 1D, which is important to the experiments on the quantum gases confined in the 1D optical lattices.

La diffraction tridimensionnelle (3d) des ondes sismiques par des structures a geometrie bidimensionnelle (2d) est etudiee par la methode indirecte d'elements de frontiere (ibem, pour indirect boundary element method). Les ondes incidentes peuvent arriver en dehors du plan 2d et, en consequence, la diffraction est 3d avec couplage de tous les types d'onde. Ce travail est divise en trois parties. La theorie de ibem et son extension aux problemes de diffraction 3d par des structures 2d sont presentees dans la premiere partie. La deuxieme est consacree a l'application de la methode pour l'etude de la diffraction et de l'amplification par des reliefs topographiques et des vallees sedimentaires. La derniere partie consiste en l'etude d'une suture lithospherique et en une simulation numerique de la diffraction des ondes de surface par cette suture. Les resultats majeurs de ce travail sont a la fois de nature theorique et pratique. Ibem s'avere etre une methode precise et rapide pour simuler la diffraction 3d par des structures 2d. Elle est numeriquement stable et permet le calcul du champ d'onde complet en prenant en compte le transfert d'energie entre differentes types d'ondes. Ibem semble ainsi etre un outil prometteur pour l'interpretation de donnees sismologiques. L'analyse de donnees ainsi que les simulations numeriques de la propagation d'ondes au travers de reliefs topographiques et de vallees sedimentaires montrent que: 1) les effets 3d sont importants, 2) l'amplification due aux reliefs topographiques est faible, et 3) des ondes diffractees sont emises du sommet des reliefs. Enfin, nous avons mis en evidence un changement rapide de la structure lithospherique sous la zone sorgenfrei-tornquist par analyse d'ondes de rayleigh de longue periode. La simulation numerique montre que les ondes de rayleigh incidentes sur une telle suture sont transmises ou reflechies sous la forme d'ondes de surface ou de volume

In this thesis we explored some aspects of the dynamics around the Earth-Moon L1 and L2 points in the context of two Restricted Four Body Problems: the Bicircular Problem (BCP) and the Quasi-bicircular Problem (QBCP). Both the BCP and QBCP model the dynamics of a massless particle moving under the influence of the Sun, Earth, and Moon. Although these two models focus on the same system, it is relevant to study both because their behavior around the L2 is qualitatively different.Ðhese two models can be written in the Hamiltonian formalism as periodic time-dependent perturbations of the RTBP. To study these Hamiltonians, we used numerical tools tailored to these type of models to get an insight on the phase space. These two techniques are the reduction to the center manifold, and the computation and continuation of 2D tori.ßor the BCP, the analysis focused around the L2 point. The results obtained showed that the reduction to the center manifold, and the non-autonomous normal form computed in this thesis do not provide useful information about the neutral motion around L2. The approach taken was to compute families of 2D tori, and explore any connections and their stability. As a summary of this effort we identified a total of six families of 2D tori: two Lyapunov-type planar quasi-periodic orbits, and four vertical. One of the vertical families was obtained by direct continuation of Halo orbits from the RTBP. This showed that the family of Halo orbits from the RTBP survive in the BCP, with the understanding that this new family is Cantorian. It was also shown that one of the other vertical families is Halo-like. Hence, members of this family may be potential candidates for future space missions. However, these tori are hyperbolic, as opposed the ones coming directly from the RTBP Halo obits, which are partially elliptic. It was also shown that this family of Halo-like tori comes from a family of quasi-periodic orbits in the RTBP that are resonant with the frequency of the Sun. Hence, these family of Halo-like orbits in the BCP have their counterparts in the RTBP.ßor the QBCP, the focus of the analyses was there Earth-Moon L1 and L2 points. In this model, the reduction to the center manifold provided relevant qualitative information about the dynamics around L1 and L2. The main takeaway was that L1 and L2 had a similar qualitative behavior. In both cases there were two families of quasi-periodic Lyapunov orbits, one planar and one vertical. It was also shown that the quasi-periodic planar Lyapunov family underwent a (quasi-periodic) pitchfork bifurcation, giving rise to two families of quasi-periodic orbits with an out-of-plane component. Between them, there was a family of Lissajous quasi-periodic orbits, with three basic frequencies. Qualitatively, the phase space of the center manifold, as constructed in this thesis, resembled the phase space of the center manifold of the RTBP around L1 and L2. In the QBCP we also continued families of invariant 2D tori, and for both L1 and L2. In these cases, the quasi-periodic planar and vertical families were continued. The bifurcations of the quasi-periodic planar Lyapunov were identified. A conclusion from this numerical experiment was that the family of out-of-plane orbits born from the bifurcation seemed not to be the RTBP Halo counterparts in the QBCP. The RTBP Halo orbits do survive in the QBCP, but do not seem to be connected to the quasi-periodic planar Lyapunov family. ßinally, and also in the context of the BCP and the QBCP, numerical simulations to study transfers from a parking orbit around the Earth to a Halo orbit around the Earth-Moon L2 point were studied. The main conclusion is that the invariant manifolds of the target orbits studied intersect with potential parking orbits around the Earth. The relevance of this result is that it shows that there are one-maneuver transfers from a vicinity of the Earth to Earth-Moon L2 Halo orbits. This is not case when using the RTBP as reference model. Experiments were done for both the BCP and the QBCP, and in all cases is it was shown that the total cost in terms of ∆V and transfer time is comparable to other techniques requiring two or more maneuvers.
En aquesta tesi explorem alguns aspectes de la dinàmica al voltant dels punts L1 i L2 Terra-Lluna en el context de dos problemes restringits de quatre cossos: el problema bicircular (PBC) i el problema quasi-circular (PQBC). Tant el PBC com el PQBC modelen la dinàmica d’una partícula sense massa que es mou sota la influència del Sol, la Terra i la Lluna. Tot i que aquests dos models es centren en el mateix sistema, és rellevant estudiar-los tots dos perquè el seu comportament al voltant de la L2 és qualitativament diferent. Aquests dos models es poden escriure en el formalisme hamiltonià com a pertorbacions periòdiques del problema restringit dels tres cossos (PRTC) dependents del temps. Per estudiar aquests hamiltonians, utlitzem eines numèriques adaptades a aquest tipus de models per obtenir una idea de l’espai de fases. Aquestes dues tècniques són la reducció a la variety central i el càlcul i la continuació de tors 2D. Per al PBC, l'anàlisi es centra al voltant del punt L2. Els resultats obtinguts mostren que la reducció a la varietat central i la forma normal no autònoma calculada en aquesta tesi no proporcionen informació útil sobre el moviment neutre al voltant de L2. L'enfocament adoptat es calcular famílies de tors 2D, i explorar les seves connexions i estabilitat. Com a resum d’aquest esforç, s'identifiquen un total de sis famílies de tors 2D: dues famílies d'òrbites quasi-periòdiques planes tipus Lyapunov i quatre verticals. Una de les famílies verticals s'obté per continuació directa de les òrbites Halo del PRTC. Això demostra que la família de les òrbites Halo del PRTC sobreviuen al PBC, entenent que aquesta nova família és cantoriana. També es demostra que una de les altres famílies verticals és semblant a les Halo. Per tant, els membres d’aquesta família poden ser candidats potencials per a futures missions espacials. No obstant això, aquests tors són hiperbòlics, a diferència dels que provenen directament de les Halo del PRTC, que són parcialment el·líptics. També es mostra que aquesta família de tors semblants a les Halo prové d’una família d’òrbites quasi-periòdiques del PRTC que són ressonants amb la freqüència del Sol. Per tant, aquestes famílies d’òrbites semblants a les Halo al PBC tenen els seus homòlegs al PRTC. Per al PQBC, el focus de les anàlisis es troba en els punts L1 i L2 Terra-Lluna. En aquest model, la reducció a la varietat central proporciona informació qualitativa rellevant sobre la dinàmica al voltant de L1 i L2. El principal resultat és que L1 i L2 tenen un comportament qualitatiu similar. En ambdós casos hi ha dues famílies d’òrbites quasi-periòdiques tipus Lyapunov, una plana i una vertical. També es demostra que la família plana quasi-periòdica tipus Lyapunov sobrevé una bifurcació tipus pitchfork (quasi-periòdica), donant lloc a dues famílies d’òrbites quasi periòdiques amb un component vertical. Entre ells, hi havia una família d’òrbites quasi-periòdiques tipos Lissajous, amb tres freqüències bàsiques. Qualitativament, l’espai de fase de la varietat central, tal com es construeix en aquesta tesi, s’assembla a l’espai de fase del la varietat central del PRTC al voltant de L1 i L2. Al PQBC també es continuen famílies de tors 2D invariants, tant per a L1 com per a L2. En aquests casos, es continuen les famílies planes i verticals quasi-periòdiques. Durant aquest procés es troben bifurcacions a les families d'òrbites quasi-periòdiques planes. Una conclusió d’aquest experiment numèric és que la família d’òrbites amb component vertical nascudes de la bifurcació no són les contraparts de les Halo de PRTC. Les òrbites Halo de PRTC sobreviuen en el PQBC, però no semblen estar connectades a la família plana quasi-periòdica. Finalment, i també en el context del PBC i el PQBC, es s'estudien simulacions numèriques per estudiar les transferències des d’una òrbita d’estacionària al voltant de la Terra fins a una òrbita Halo al voltant del punt L2 Terra-Lluna. La principal conclusió és que les varietats invariants de les òrbites objectiu estudiades passen molt a prop de la Terra. La rellevància d’aquest resultat és que mostra que hi ha transferències d’una maniobra des de d'una òrbita al voltat de Terra a les òrbites L2 Halo Terra-Lluna. No és així quan s’utilitza el PRTC com a model de referència. Es fan experiments tant per al BCP com per al QBCP, i en tots els casos es demostra que el cost total en termes de ∆V i temps de transferència és comparable a altres tècniques que requereixen dues o més maniobres.

Une combinaison de moyens passifs et actifs de contrôle d'écoulement est utilisée pour réduire la traînée aérodynamique produite par le sillage turbulent d'une géométrie simplifiée de véhicule à culot droit. Ces sillages sont caractérisés par deux aspects principaux : une traînée de pression importante liée à la séparation massive de l'écoulement, et des asymétries à grande échelle. Ces dernières, se manifestant sous forme de dynamique bimodale ou de brisure de symétrie permanente, contribuent pour environ 10% de la traînée de pression. L'étude des basculements de sillage transitoires en dynamique bimodale s'opérant au travers d'états symétriques du sillage permet d'isoler le mécanisme responsable de l'augmentation de traînée des états à brisure de symétrie. Une interaction et un couplage entre l'écoulement de recirculation issu d'un côté et la couche cisaillée opposée propre aux états à brisure de symétrie déclenche et amplifie les instabilités de couche cisaillée, ce qui conduit à une augmentation de l'écoulement d'entraînement et de la traînée. Il est montré que ce mécanisme est caractéristique des sillages de corps à culot droit.Une stratégie de contrôle actif de l'écoulement combinant des jets pulsés émis tangentiellement aux bords de fuite et de surfaces courbées miniatures affleurantes est utilisée pour réduire la traînée de pression de la géométrie. Le recollement de l'écoulement sur les surfaces courbées résulte en un rétreint fluidique du sillage se traduisant par une réduction de trainée jusqu'à 12%, indépendamment de l'asymétrie initiale du sillage, et est notablement influencé par l'échelle de temps caractéristique de l'instationnarité du forçage. Une combinaison minutieuse entre l'échelle de temps du forçage et la taille caractéristique des surfaces courbées permet d'exploiter tout le potentiel de réduction de traînée de cet effet Coanda instationnaire comme le montre un modèle simple d'écoulement permettant la mise en évidence de lois d'échelles caractérisant le phénomène. De plus, un forçage localisé selon certaines arêtes seulement permet d'interagir avec les asymétries à grande échelle du sillage et impacte de manière très différente la traînée selon l'équilibre su sillage non-forcé. La symétrisation du sillage résultant d'un forçage asymétrique permet une réduction de traînée d'environ 7% à coup énergétique réduit. Des éléments clefs sont donnés concernant l'adaptation de la localisation du contrôle pour une réduction de traînée en présence de différentes asymétries du sillage. Comme le changement d'équilibre global du sillage résulte de changements géométriques et d'écoulement mineurs, des stratégies de contrôle adaptives et robustes sont essentielles pour les applications dans l'industrie automobile
Combination of passive and active flow control are used to experimentally reduce the aerodynamic drag produced by the turbulent wake past a simplified vehicle geometry with a blunt base. Such wakes are characterized by two main features: important pressure drag linked to the massive flow separation, and large-scale asymmetries. The latter,manifesting as bi-modal dynamics or permanent symmetry-breaking, are shown to contribute for around 10% of the pressure drag. The study of the transient wake reversais occurring in bi-modal dynamics though symmetric states enables to isolate the flow mechanism responsible for increased drag in symmetry-breaking states. An interaction and coupling between the recirculating flow from one side and the shear-layer from opposite side peculiar to symmetry-breaking states triggers shear-layer instabilities and their amplification leading to increased flow entrainment and drag.This mechanism is shown to be characteristic of the wakes of blunt bodies.An active flow control strategy combining tangential pulsed jets along the trailing-edges and small flush-mounted curved surfaces is used to reduce the pressure drag of the geometry. The flow reattachment and separation on thecurved surfaces results in a fluidic boat-tailing of the wake leading to drag reductions up to 12%, independently of the unforced large-scale asymmetry of the wake, and is noticeably influenced by the time-scale of unsteadiness of the forcing. Careful combination between forcing time-scale and size of the curved surfaces is needed to achieve ail thepotential of this unsteady Coanda effect in drag reduction as shown from a simple flow model providing scaling laws of the phenomenon. The model provided allows for an extension of the flow control mechanism to separated flows moregenerally. Furthermore, forcing along only selected edges enables to interact with the large-scale wake asymmetries and has very different impact on the drag depending on the unforced wake equilibrium. Symmetrisation of the wake through asymmetric forcing leads to 7% drag reduction at a reduced energetic cost. Key ingredients are provided to adapt forcing strategies for drag reduction in presence of various wake asymmetries. As global wake equilibrium changes result from minor geometric and flow conditions changes, adaptive and robust flow control strategies are essential for industrial automotive applications

碩士
國立虎尾科技大學
機械與機電工程研究所
98
With the high precision application in areas such as micro machine and precision machine. Adhesion and friction become more and more important than inertial force between the contact surfaces and the dimensionless separation. In the micro machine and precision machine particles are often presented at contact interfaces. And these factors will affect the adhesion, friction and wear between the contact surfaces. In this paper, a three-body friction with adhesion effects model for rough surface with particles, material of surfaces and surface effects are proposed in order to understand the effects of particles, material of surface and surface effects between surfaces on contact characteristics. This work establishes a new three-body microcontact model to calculate elastic contact area, plastic contact area, elastic-plastically deformed contact area, and infers that adhesion friction, deformation friction and ratchet friction between the contact surfaces. The results show that the particle size and particle density dominates the friction value for low mean separation between rough surfaces. Beyond the critical value of mean separation, the important factor in affecting total friction value is surface friction. The critical value have the sequence for the different plasticity index: (d/σ)Ψ0.5 > (d/σ) Ψ0.7> (d/σ) Ψ1.0> (d/σ) Ψ1.5 > (d/σ) Ψ2.5. The larger the wear particle size and particle density, the higher friction value and critical separation value for precision machine and micromachine under the same operation conditions.

碩士
國立虎尾科技大學
機械與機電工程研究所
96
The development of the micro-electromechanical system (MEMS) has already come into the industrial application from the academic research gradually, more and more attention is being paid on the research in MEMS, include such many kinds of knowledge and technology as optical communication, high density storage, green energy and biomedicine. Adhesion and friction become more important than inertial force, when the volume of a micro-device is decreased. In the MEMS and precision machine, particles and liquid films are often presented at contact interfaces, these factors will affect the adhesion, friction, wear and thermal properties between the contact surfaces.In this paper, a three-body adhesion model for rough surfaces with particles and liquid films are proposed in order to understand the effects of particles and liquid films between surfaces on contact characteristics. This work establishes a new three-body contact model to calculate elastic contact area, plastic contact area, elastic-plastically deformed contact area, adhesion friction, deformation friction and ratchet friction between the contact surfaces. The second objective is manipulation AFM and NanoTest to compare date. The results show that the particle size dominates the friction value for low mean separation between rough surfaces. Beyond the critical value of mean separation, the important factor in affecting total friction value is surface friction. The critical value have the sequence for the different plasticity index: (d/σ)Ψ2.5 > (d/σ) Ψ1.5 > (d/σ) Ψ0.5. The larger the wear particle size, the higher friction value and critical separation value for three materials under the same operation conditions. Capillary force and contact force decreases with the increase in dimensionless mean separation for the same film thickness. Capillary forces ratio of nickel is larger than the materials of steel and silicon under the same roughness parameters.

碩士
國立中正大學
運動與休閒教育所
98
Purpose: To sieve out 9 combinations from different functions (including gradient, resistance, and step frequency) of Yowza Elliptical Trainer C8.5e (C8.5e), Smooth Agile Trainer WT100 (WT100), and Smooth Agile DMT C7.5e (C7.5e) by Taguchi orthogonal array. And to compare the effects of three elliptical trainer and three motion parameters on the human body with the raw data, signal-to-noise ratio (S/N) and factor response from user’s rating of perceived exertion (RPE), physical response [oxygen uptake (V‧O2) and heart rate (HR)] in different exercise parameters combination test. Methods: 18 health male students as participants (21.56±2.64 yrs, 173.44±5.02 cm, 70.75±10.64 kg). After 10 minutes rest by sitting, participant had completed 3 elliptical trainers exercise tests (each test contain 9 combinations with 3 motion parameters, each combination proceed 4 minutes, rest 5 minutes among combinations), 24 hours separated from 3 elliptical trainers exercise tests. Using Cortex gas analysis system and Polar heart rate monitor record V‧O2 and HR. Recorded participant’s RPE at 4th minute in each test. Data progressed by One-way ANOVA to compare the difference among the effects of 3 elliptical trainers on the human body. And to compare the difference among effects of 3 elliptical trainer motion parameters on the human body by SN ratio and factor response. Result: The difference among the effects of three elliptical trainers on RPE, V‧O2, and HR were as described. WT100 was higher than C8.5e and C7.5e significantly; and C7.5e was higher than C8.5e significantly. To get smallest RPE, three elliptical motion parameters (gradient, resistance, and step frequency) should set at smallest level (15°, 83watts, 40rpm). To get highest V‧O2, and HR, three elliptical motion parameters should set at highest level (34°, 181watts, 60rpm). Resistance was the 1st effective motion parameter to RPE, V‧O2, and HR, the 2nd was step frequency, and the 3rd was gradient. Conclusion: It was an effective method to compare the difference among effects of 3 elliptical trainers and 3 elliptical trainer motion parameters on RPE, V‧O2, and HR by One-way ANOVA, SN ratio, and factor response with Taguchi orthogonal array. Through this study can figure out the benefit and characteristic of different elliptical trainers.

Accurate quantum mechanical reactive scattering calculations within the framework of symmetrized hyper spherical coordinate techniques are presented for several processes involving collisions of an electron with a hygrogen atom and an atom with a diatomic molecule in three-dimensional space, and the collinear collision of an atom with a diatomic molecule. In addition to the interest of the processes themselves, the results are compared with previous experimental and theoretical results in such a way as to provide tests of the general usefulness of the methods used.

The general theory for the calculation of accurate differential cross sections in the reactive collision of an atom with a diatomic molecule including the geometric phase effect in three-dimensional space is described. This methodology has permitted, for the first time, the calculation of integral and differential cross sections over a significantly larger range of collision energies (up to 2.6 eV total energy) than previously possible for the system H + H_2.

We present numerical solutions of the quantum mechanical streamlines of probability current density for collinear atom-diatom reactions. It is used to study the barrier height dependence of dynamics on the C1 + HC1 reaction.

Physically active men and woman may be less likely than their inactive peers to become overweight. Exercise has a favourable effect on body fat distribution, with a reduction in waist-to-hip ratio with increased exercise. Exercise is especially important in maintaining weight loss in overweight individuals. Physical activity can directly affect both total energy intake and total energy expenditure. Physical activity can also affect fat balance and it is becoming clear that imbalances in total energy are largely due to imbalances in the distribution of fat. Exercise also has additional, beneficial effects on most of the metabolic risk factors for cardiovascular disease and non-insulin dependent diabetes mellitus. Exercise testing provides a basis for the design of training programs and allows for monitoring progress throughout the training program. Used properly, testing and monitoring is useful to both trainers and subjects. Therefore, exercise in conjunction with an appropriate diet is beneficial to overweight individuals and provided that feasible methods and motivation are available, we recommend exercise as an important part of a weight control program. The aim of this study was to determine whether HMB supplementation will increase the Lean Body Mass (LBM) and muscle power output (measured as the load a subject can bench press) of males who gym for recreational purposes, after a combination of resistance weight training, eating a balanced set diet and supplementation with HMB for 8 weeks. Two homogenous groups of 20 males were evaluated for initial strength capabilities and body composition. For 8 weeks the subjects lifted weights three times a week and followed a balanced diet. Creatinekinase activity decreased with HMB supplementation. Gains in muscle power output were greater in the experimental group, and fat percentage decreases were recorded with HMB supplementation.
Dissertation (MSc)--University of Pretoria, 2011.
Physiology
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