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1
KOEHLER, KAI. "Torsion analytique complexe." Paris 11, 1993. http://www.theses.fr/1993PA112158.
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Dans cette these, on etudie plusieurs aspects de la torsion complexe de ray-singer et de ses generalisations. Cette torsion est un nombre reel associe a un fibre vectoriel hermitien holomorphe sur une variete complexe compacte munie d'une metrique hermitienne. Elle est un determinant generalise du laplacien de hodge-kodaira. La premiere partie traite des formes de torsion analytique superieures. On montre que ces formes permettent de construire un morphisme d'image directe dans le k-theorie arithmetique de gillet et soule. La deuxieme partie porte sur une generalisation equivariante de la torsion pour les varietes munies d'une action d'un groupe. On calcule cette torsion equivariante pour le fibre trivial sur les espaces projectifs complexes. Dans la troisieme partie, on definit les formes de torsion pour des fibres en tores, qui ne definissent pas necessairement des submersions kahleriennes. On les calcule explicitement et on determine certaines proprietes de ces formes
2
Volkin, Ronald S. "Estimation of rotor blade torsional deformations from measured blade torsion moments." Thesis, Monterey, California. Naval Postgraduate School, 2002. http://hdl.handle.net/10945/6003.
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Approved for public release; distribution is unlimitedThe strain pattern analysis (SPA) method is applied to estimate rotor blade torsional deflections. The SPA technique requires calculated mode shapes for the tested rotor blade and strain measurements from the rotor's wind tunnel or flight test. The Holzer method is developed to calculate the required mode shapes from rotor blade stiffness and mass properties and the torsional equation of motion. The Holzer method is tested with numerous theoretical and experimental cases and is proven accurate. The strain measurements are from wind tunnel tests conducted by the Army, NASA, United Technologies Research Center (UTRC) and Sikorsky at DNW with a (1:5.73) model-scale UH-60A rotor blade with an advance ratio of 0.301, an advancing tip Mach number of 0.8224 and an average Reynolds number of 1,278,729. The SPA method predicts slightly larger torsional deflections that compare well with the overall trend and range of UTRC static method integrated deflections. The SPA method was evaluated to determine the tolerance to change in the number of measurements and the modes applied, errors in the measurements, and errors in rotor blade stiffness and mass properties. The method is tolerant to all effects except a decrease in the number of measurements and modes.
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Charalambides, Stelios, and n/a. "Topics in torsion theory." University of Otago. Department of Mathematics & Statistics, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070216.161043.
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The purpose of this thesis is to generalize to the torsion-theoretic setting various concepts and results from the theory of rings and modules. In order to accomplish this we begin with some preliminaries which introduce the main ideas used in torsion theory, the major ones being [tau]-torsion and [tau]-torsionfree modules as well as [tau]-dense and [tau]-pure submodules. In the first chapter we also introduce a new concept, that of a [tau]-compact module, which is basic enough to deserve a place among the preliminaries.
The results that we obtain fall into three areas which are to a certain degree interrelated. The first area is on [tau]-Max modules, which we introduce as a torsion-theoretic analogue of Max modules. The main aim is to generalize a well-known result by Shock which characterizes Noetherian rings by using the socle, the radical and Max modules. All of these concepts have torsion-theoretic counterparts which we utilize in our generalization. Furthermore, we define and characterize left [tau]-Max rings and apply the torsion-theoretic version of Shock�s theorem to obtain a characterization of [tau]-short modules motivated by a recent article in which short modules were introduced.
The second area deals with various flavours of [tau]-injectivity, some known and some new. We introduce [tau]-M-injective and s-[tau]-M-injective modules and examine their relationship with the known concepts of [tau]-injective and [tau]-quasi-injective modules. We then provide an improved version of the Generalized Fuchs Criterion which characterizes s-[tau]-M-injective modules, and give a generalization of Azumaya�s Lemma. We also prove that every M-generated module has a [tau]-M-injective hull which is unique up to isomorphism and show how this is linked to the [tau]-quasi-injective hull. We then examine [Sigma]-[tau]-injectivity, generalizing well-known results by Faith, Albu and Năstăsescu and Cailleau which provide necessary and sufficient conditions for the [Sigma]-[tau]-injective property, the [Sigma]-s-[tau]-M-injective property and for a direct sum of [Sigma]-s-[tau]-M-injective modules to be [Sigma]-s-[tau]-M-injective.
In the third area we introduce a couple of new concepts with the aim of bringing to the torsion-theoretic setting the concept of a CS or extending module. The approach is twofold. The first is via [tau]-CS modules which serve as a generalization of CS modules as well as [tau]-quasi-continuous, [tau]-quasi-injective and [tau]-injective modules, and the second is via s-[tau]-CS modules which are a special case of CS modules. Our motivation is to provide a torsion-theoretic analogue of a well-known result by Okado which characterizes Noetherian modules. We have some partial results using s-[tau]-CS modules and a nice torsion-theoretic analogue, albeit without the use of [tau]-CS or s-[tau]-CS modules. We also examine the relationship between our relative versions of CS modules with those of other authors and obtain refinements to some of their results.
4
Briginshaw, James Andrew. "Conical singularities with torsion." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.625050.
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Burnett, J. "Coframes, spinors and torsion." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1335617/.
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This thesis is based on five articles, four of which have been published in the Journal of Mathematical Physics, Physical Review D, Modern Physics Letters A and Journal of High Energy Physics. The fifth has been submitted to Mathematika. In these works we study several distinct problems within the broad subject area of Mathematical Physics. The common feature is that all these works deal with rotations of one form or another. In particular, we show an equivalence between the massless and massive Dirac equations and models based on the concept of rotating material points. We also solve an open problem in Einstein-Cartan theory, namely, we find a natural matter source for a non-trivial spin angular momentum tensor. Finally, we construct a complete class of non-standard (non-local) spinor field theories and examine their possible applications in Cosmology.
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Whiteley, Rodney John. "Humeral torsion and throwing." Thesis, The University of Sydney, 2009. https://hdl.handle.net/2123/28206.
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This thesis is concerned with the act of throwing, and particularly with a variation of a
skeletal feature — humeral retrotorsion — which has been shown to be associated with high
level throwing. In the introductory chapters 1 to 3, the importance of throwing is established,
followed by a description of humeral torsion, and an account of the development of humeral
torsion. It is noted that there is a lack of consistency in the description and measurement of
humeral torsion, along with some technical and practical difficulties in the currentlyemployed
methods of its quantification. In the chapter 4 the rationale for an alternate method
of measuring humeral torsion using the relation between the bicipital groove and the
orientation of the humeral head is proposed.
In the first of a series of experiments, the inter-rater reliability of two methods of measuring
humeral torsion both of which involve standardising the position of the deepest portion of the
bicipital groove and measuring the inclination of the ulna are explored. In the first method
direct palpation of the bicipital groove is employed, and this is compared to ultrasound-assisted
visualisation. Excellent inter-rater reliability is demonstrated for the ultrasound-assisted
method in the dominant and non-dominant arms of 16 non-athletic adult subjects
(ICC2_1=0.98, and 0.94) while the reliability of the palpation method was seen to be poor
(ICC2,1=0.51 and 0.49).
For the remainder of the experiments, the ultrasound-assisted method of visualisation was
employed to measure humeral torsion. The next experiment investigated the side-to-side
difference in humeral torsion in a group of throwing athletes (85 adult males, 16 adult females,
35 adolescent males, and 37 adolescent females), swimmers (l9 adolescent females, and 10
adolescent males), and 16 non-athletic adults. Greater dominant arm retrotorsion (11.90 :I:
105°) was displayed in the arms of the throwers irrespective of age or gender. The swimmers
showed a lesser inclination toward increased dominant arm retrotorsion (6.4° d: 9.9°), and the
non-athletic adults showed no detectable sidedness effect (13° :|: 89°). A wide range of
between-subject variation was displayed in this data, with values for the throwing athletes
varying from a maximum of 38° greater dominant arm retrotorsion to 18° greater dominant
arm antetorsion.
In the following experiment, the relation between humeral torsion and obtained
proprioception was examined in 16 high-level adolescent male baseball players. In the non-dominant
arm, a strong (F088) and significant (p<0.001) relationship was established with
increasing retrotorsion being correlated with better proprioceptive acuity. In the non-dominant
arm the relationship was weaker (0.41) and did not reach significance (p=0.120). It is
hypothesised that the described relation for the non-dominant arm is suggestive of an
underlying physiological effect that is masked by prodromal injury to the proprioceptive
systems in the dominant arm.
7
Ferreira, Ana Cristina Castro. "Riemannian geometry with skew torsion." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526550.
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Hassell, Andrew. "Analytic surgery and analytic torsion." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/32611.
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Nyirenda, Darlison. "Torsion points on elliptic curves." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80120.
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Thesis (MSc)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The central objective of our study focuses on torsion points on elliptic curves. The case of elliptic curves over finite fields is explored up to giving explicit formulae for the cardinality of the set of points on such curves. For finitely generated fields of characteristic zero, a presentation and discussion of some known results is made. Some applications of elliptic curves are provided. In one particular case of applications, we implement an integer factorization algorithm in a computer algebra system SAGE based on Lenstra’s elliptic curve factorisation method.
AFRIKAANSE OPSOMMING: Die hoofdoel van ons studie is torsiepunte op elliptiese krommes. Ons ondersoek die geval van elliptiese krommes oor ‘n eindige liggaam met die doel om eksplisiete formules vir die aantal punte op sulke krommes te gee. Vir ‘n eindig-voortgebringde liggaam met karakteristiek nul bespreek ons sekere bekende resultate. Sommige toepassings van elliptiese krommes word gegee. In een van hierdie toepassings implementeer ons ‘n heeltallige faktoriseringalgoritme in die rekenaar-algebrastelsel SAGE gebaseer op Lenstra se elliptiese krommefaktoriseeringmetode.
10
Krantz, Thomas. "Holonomie des connexions sans torsion." Nancy 1, 2007. http://docnum.univ-lorraine.fr/public/SCD_T_2007_0030_KRANTZ.pdf.
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Dans une premier temps nous étudions les représentations de dimension finie des algèbres de Lie en rapport avec le treillis des sous-représentations. Nous considérons le cas où la représentation laisse invariant deux paires de sous-espaces supplémentaires. Nous montrons que la représentation peut être décomposée dans ce cas en une somme de trois sous-représentations canoniques que nous caractérisons. Nous précisons les résultats dans le cas d'une représentation préservant deux sous-espaces supplémentaires et une forme réflexive, et aussi dans le cas métrique. Dans une deuxième partie géométrique nous appliquons les résultats précédents à l'étude des représentations d'holonomie d'une variété munie d'une connexion sans torsion ou en particulier réflexive ou pseudo-Riemannienne. Enfin nous examinons de plus près les représentations de type ‘ somme directe de V et V dual ‘, respectivement ‘V tenseur la représentation triviale de dimension 2’ , qui apparaissent dans le cadre de cette étude, et nous caractérisons les connexions sans torsion admettant une telle représentation d'holonomieWe study the finite-dimensional Lie algebra representations in connection with their lattice of subrepresentations. We consider the case where the representation admits two pairs of supplementary invariant subspaces. We show that in this case the representation admits a canonical decomposition in three subrepresentations with well defined caracteristics. We strengthen the results for the situation where the representation admits a pair of supplementary invariant subspaces and an invariant reflexive form, respectively an invariant metric. In the geometric part we apply the preceding results to the study of the holonomy representations of a manifold equipped with a torsion-free connection or in particular a pseudo-Riemannian manifold. Finally we have a closer look at representations of type ‘direct sum of V and V dual’ or ‘V tensor the trivial representation of dimension 2’, which appear in this context, and we caracterize the torsion-free connections admitting a holonomy representation of this kind
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Zhang, Weiping. "Invariant êta et torsion analytique." Paris 11, 1993. http://www.theses.fr/1993PA112131.
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1. Une preuve par la methode du noyau de la chaleur du theoreme d'indice equivariant d'atiyah, bott, segal et singer pour des operateurs de dirac. 2. Un calcul de la limite adiabatique de l'invariant eta d'operateurs de dirac sur des fibres en cercles. 3. Une formule de congruence du type de rokhlin en dimension superieure qui etend le theoreme de la divisibilite d'atiyah-hirzebruch pour le genre a, et la congruence de rokhlin en dimension 4. 4. Un resultat sur le rapport des invariants eta pour des varietes plongees. Et comme application, une preuve du theoreme de l'indice mod 2 d'atiyah-singer pour des operateurs de dirac. 5. Un resultat comparant les metriques de ray-singer et de milnor sur le determinant de la cohomologie d'un fibre plat. Ce resultat etend les theoremes anterieurs de cheeger et muller, qui sont valables pour des fibres plats unimodulaires
12
Schwiebert, Ryan C. "Faithful Torsion Modules and Rings." Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1304363925.
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Krantz, Thomas Bérard Bergery Lionel. "Holonomie des connexions sans torsion." [S.l.] : [s.n.], 2007. http://www.scd.uhp-nancy.fr/docnum/SCD_T_2007_0030_KRANTZ.pdf.
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Bénard, Léo. "Reidemeister torsion on character varieties." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS020/document.
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Dans cette thèse on étudie un invariant topologique des variétés de dimension 3, la torsion de Reidemeister, comme un objet global sur les variétés de caractères du groupe fondamental dans SL(2,C). Dans le cas du complexe cohomologique associé à la représentation adjointe, on définit la torsion « adjointe » comme une forme différentielle méromorphe sur la variété des caractères. On reliera l’apparition de pôles ou de zéros à :-des singularités de la variété des caractères-la topologie de certaines surfaces incompressibles plongées, produites via la théorie de Culler-Shalen.On obtiendra, comme conséquence de ces résultats, une formule reliant le genre de ces surfaces incompressibles, et celui de la variété des caractères.Dans le cas du complexe standard, la torsion « acyclique » est une fonction méromorphe sur la variété des caractères. Une étude poussée des pôles apparaissant aux points à l’infini nous permettra, entre autre, de donner des conditions suffisantes pour que la torsion soit non constanteIn this PhD dissertation, we study a topological invariant of 3-manifolds, namely the Reidemeister torsion, as globally defined on character varieties of the fundamental group in SL(2,C). The « adjoint » torsion will be the torsion of the cohomological complex associated to the adjoint representation. We explain that it can be seen as a meromorphic differential form on the character variety, and we aim to understand its poles and zeros. They will be related with -singular points of the character variety -the topology of incompressible surfaces embedded in the 3-manifold, provided by the Culler-Shalen theory. As an application, we prove a relation between the genus of those incompressible surface and the genus of the character variety. The « acyclic » torsion of the standard complex is a rational function on the character variety. We study its poles at infinity in the character variety, and we give sufficient conditions for this torsion to be non constant
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Ritchie, Stephen John Kerr. "The high speed double torsion test." Thesis, Imperial College London, 1996. http://hdl.handle.net/10044/1/11437.
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He, Mu. "The Torsion Angle of Random Walks." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1242.
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In this thesis, we study the expected mean of the torsion angle of an n-stepequilateral random walk in 3D. We consider the random walk is generated within a confining sphere or without a confining sphere: given three consecutive vectors →e1 , →e2 , and →e3 of the random walk then the vectors →e1 and →e2 define a plane and the vectors →e2 and →e3 define a second plane. The angle between the two planes is called the torsion angle of the three vectors. Algorithms are described to generate random walks which are used in a particular space (both without and with confinement). The torsion angle is expressed as a function of six variables for a random walk in both cases: without confinement and with confinement, respectively. Then we find the probability density functions of these six variables of a random walk and demonstrate an explicit integral expression for the expected mean torsion value. Finally, we conclude that the expected torsion angle obtained by the integral agrees with the numerical average torsion obtained by a simulation of random walks with confinement.
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Lauer, Joseph. "Cubulating one-relator groups with torsion." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101861.
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Let
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Ng, Puiman. "Torsion theories and Auslander-Reiten sequences." Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1182.
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Chapter 0 gives a gentle background to the thesis. It begins with some general notions and concepts from homological algebra. For example, not only are the notions of universal property and of duality central to the flavour of the subject, they are also suggestive in understanding mathematics at another depth. In category theory, objects and morphisms are the two main elements in a category, and notions such as kernels and cokernels are defined in terms of objects together with morphisms. In accordance with it, the morphisms are given a very subtle signifcance within a category. The chapter then introduces the notion of a triangulated category, where due to the lack of uniqueness of certain morphisms described in the axioms, is allowed to be far from an abelian category. A few examples of triangulated categories are given, the homotopy category, the derived category and certain stable cat- egories. The chapter ends with a little description of an Auslander-Reiten quiver de ned on a Krull-Schmidt category, as well as the notions of Serre functor and of Auslander-Reiten triangles in subcategories. The introduction chapter selects lemmas and theorems not only to be referenced in later chapters, but also those which can induce good intuition on the reader, for example, in their capacity of being analogues to each other, in the interplay between them and in their different suggestiveness in approximating or generalizing concepts in different ways and directions. Chapter 1 studies torsion pairs in abelian categories and torsion theories with torsion theory triangles in triangulated categories. It then gives a necessary and su cient condition for the existence of certain adjoint functors in triangulated categories. Intuitively, they are all different expressions of subcategories approximating their ambient categories. The chapter goes on to introduce two special cases of torsion theories, namely t-structures and split torsion theories, and finishes with a characterization of a split torsion theory and a classiffcation of split torsion theories in a chosen derived category. There is a very close and subtle relationship between the existence of torsion theory triangles and the existence of Auslander-Reiten triangles. Chapter 2 studies the existence of Auslander-Reiten sequences in subcategories of mod( ), where is a nite-dimensional k-algebra over the eld k, based on the theory of the existence of Auslander-Reiten triangles in subcategories developed by J rgensen. The existence theorems strengthen the results by Auslander and Smal and by Kleiner. Chapter 3 sees that quotients of certain triangulated categories are triangulated and are in addition derived categories, appealing to a theorem which is a slight variation of the results by Rickard and Keller. In this chapter, the Auslander-Reiten triangles play a predominant role in re ecting the tri angulation structure of a triangulated category, and the Auslander-Reiten triangles can be read o from the Auslander-Reiten quiver. The cluster category D of Dynkin type A1 was introduced by J rgensen. One of its several de nitions, which is completely analogous to the de nition of the cluster category of type An, motivates us to say that D is a cluster category of type A1. In the result by Holm and J rgensen, the cluster tilting subcategories of D were shown to be in bijection with certain maximal sets of non-crossing arcs connecting non-neighbouring integers. Chapter 4 generalizes the result by giving a bijection between torsion theories in D and certain configurations of arcs connecting non-neighbouring integers. Finally, a few examples, characterizing all t-structures and co-t-structures in D, are given.
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Heineke, Reece Ian. "Inflationary torsion in Einstein-Cartan theory." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612377.
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Raimbault, Jean. "Torsion homologique dans les revêtements finis." Paris 6, 2012. http://www.theses.fr/2012PA066646.
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Le thème central de cette thèse est l''etude des groupes d'homologie et de cohomologie entières, et plus particuli`erement de leur sous-groupes de torsion, des vari'et'es de dimension 3. On s'intéresse principalement au comportement de ces derniers dans des suites de revêtements finis, et ce probl`eme est reli'e `a l'approximation des invariants ell^2 de revêtements infinis. Dans une première partie (correspondant aux chapitres 1 et 2) on s'intéresse au cas des revêtements ab'eliens d'un complexe cellulaire quelconque et on 'etablit en toute généralité des résultats sur la croissance de la partie de torsion des groupes d'homologie dans les revêtements cycliques et des résultats partiels pour les revêtements ab'eliens plus g'en'eraux. La deuxi`eme partie (chapitres 3 `a 6 et Appendice A) traite uniquement de variétés hyperboliques de volume fini en dimension 3 ; on s'intéresse d'abord au probl`eme de l'approximation pour les invariants L^2 analytiques dans un cadre général puis on s'intéresse plus particuli`erement aux variétés de congruence. Pour ces dernières on 'etudie aussi la cohomologie entièreHe main subject of this thesis is the study of the homology and cohomology of three--manifolds with integer coefficients, with an emphasis on their torsion subgroups. We are mainly intersted in studying the latter in sequence of finite covers and this last problem is related to that of approximating \ell^2 invariants by finite ones. In a first part (corresponding to Chapters 1 and 2) we study abelian covering spaces of CW complexes. We prove in all generality results on the growth of the torsion part of the homology groups in sequences of cyclic covers and partial results for more general abelian covering spaces. The second part (which comprises Chapters 3 through 6 and the Appendix A) deals with finite-volume hyperbolic 3--manifolds. We study the problem of approximation for L^2-analytic invariants in general setting before turning to the exclusive study of congruence manifolds. For these we also deal with Reidemeister torsions and integral homologies
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Haynie, Waddy. "Torsion of Elliptical Composite Cylindrical Shells." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/28547.
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The response of elliptical composite cylindrical shells under torsion is studied. The torsional condition is developed by rotating one end of the cylinder relative to the other. Prebuckling, buckling, and postbuckling responses are examined, and material failure is considered. Four elliptical cross sections, defined by their aspect ratio, the ratio of minor to major radii, are considered: 1.00 (circular), 0.85, 0.70, and 0.55. Two overall cylinder sizes are studied; a small size with a radius and length for the circular cylinder of 4.28 in. and 12.85 in., respectively, and a large size with radii and lengths five times larger, and thicknesses two times larger than the small cylinders. The radii of the elliptical cylinders are determined so the circumference is the same for all cylinders of a given size. For each elliptical cylinder, two lengths are considered. One length is equal to the length of the circular cylinder, and the other length has a sensitivity of the buckling twist to changes in the length-to-radius ratio the same as the circular cylinder. A quasi-isotropic lamination sequence of a medium-modulus graphite-epoxy composite material is assumed. The STAGS finite element code is used to obtain numerical results. The geometrically-nonlinear static and transient, eigenvalue, and progressive failure analysis options in the code are employed. Generally, the buckling twist and resulting torque decrease with decreasing aspect ratio. Due to material anisotropy, the buckling values are generally smaller for a negative twist than a positive twist. Relative to the buckling torque, cylinders with aspect ratios of 1.00 and 0.85 show little or no increase in capacity in the postbuckling range, while cylinders with aspect ratios of 0.70 and 0.55 show an increase. Postbuckling shapes are characterized by wave-like deformations, with ridges and valleys forming a helical pattern due to the nature of loading. The amplitudes of the deformations are dependent on cross-sectional geometry. Some elliptical cylinders develop wave-like deformations prior to buckling. Instabilities in the postbuckling range result in shape changes and loss of torque capacity. Material failure occurs on ridges and in valleys. Cylinder size and cross-sectional geometry influence the initiation and progression of failure.Ph. D.
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Marcsik, John. "Analytic Torsion and Closed One Forms /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487930304688024.
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Sentieri, Francesco. "On large and small torsion pairs." Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/348239.
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Torsion pairs were introduced by Dickson in 1966 as a generalization of the concept of torsion
abelian group to arbitrary abelian categories. Using torsion pairs, we can divide complex abelian
categories in smaller parts which are easier to understand.
In this thesis we discuss torsion pairs in the category of modules over a finite-dimensional algebra, in
particular we explore the relation between torsion pairs in the category of all modules and torsion
pairs in the category of finite-dimensional modules.
In the second chapter of the thesis, we present the analogue of a classical theorem of Auslander in the
context of τ-tilting theory: for a finite-dimensional algebra the number of torsion pairs in the
category of finite-dimensional modules is finite if and only if every brick over such algebra is finite-
dimensional.
In the third chapter, we revisit the Ingalls-Thomas correspondences between torsion pairs and wide
subcategories in the context of large torsion pairs. We provide a nice description of the resulting
wide subcategories and show that all such subcategories are coreflective.
In the final chapter, we describe mutation of cosilting modules in terms of an operation on the Ziegler
spectrum of the algebra.
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Armana, Cécile. "Torsion rationnelle des modules de Drinfeld." Phd thesis, Université Paris-Diderot - Paris VII, 2008. http://tel.archives-ouvertes.fr/tel-00338117.
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Cette thèse étudie l'existence de points de torsion pour les modules de Drinfeld de rang 2 sur des extensions finies de F_q(T), pour q puissance d'un nombre premier. Notre approche suit celle de Mazur et Merel pour la torsion des courbes elliptiques sur les corps de nombres : nous introduisons un quotient de la jacobienne d'une courbe modulaire de Drinfeld, défini à l'aide d'un symbole modulaire de Teitelbaum particulier, et étudions ses propriétés. Sous une hypothèse de dualité entre algèbre de Hecke et formes modulaires pour F_q[T], ainsi qu'une hypothèse technique mineure, on montre le résultat suivant : s'il existe un module de Drinfeld de rang 2 sur une extension de degré au plus q de F_q(T), muni d'un point de torsion d'ordre un idéal premier n de F_q[T], alors le degré de n est au plus max(q,4). Nous utilisons pour cela une description de l'action de l'algèbre de Hecke sur les symboles modulaires de Teitelbaum et sur les formes modulaires pour F_q[T]. Lorsque le degré de n est petit, on obtient des résultats non conditionnels : il n'existe aucun module de Drinfeld de rang 2 sur une extension de degré au plus 2 (resp. au plus 3) de F_q(T) possédant un point de torsion d'ordre un idéal premier de degré 3 (resp. de degré 4 si q est au moins 7). Cela confirme partiellement une conjecture de Poonen et Schweizer de borne uniforme sur la torsion des modules de Drinfeld.
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Armana, Cécile. "Torsion rationnelle des modules de Drinfeld." Phd thesis, Paris 7, 2008. https://theses.hal.science/tel-00338117v2.
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Cette thèse étudie l'existence de points de torsion pour les modules de Drinfeld de rang 2 sur des extensions finies de Fq(T), pour q puissance d'un nombre premier. Notre approche suit celle de Mazur et Merel pour la torsion des courbes elliptiques sur les corps de nombres : nous introduisons un quotient de la jacobienne d'une courbe modulaire de Drinfeld, défini à l'aide d'un symbole modulaire de Teitelbaum particulier, et étudions ses propriétés. Sous une hypothèse de dualité entre algèbre de Hecke et formes modulaires pour Fq[T], ainsi qu'une hypothèse technique mineure, on montre le résultat suivant : s'il existe un module de Drinfeld de rang 2 sur une extension de degré au plus q de Fq(T), muni d'un point de torsion d'ordre un idéal premier n de Fq[T], alors le degré de n est au plus max(q,4). Nous utilisons pour cela une description de l'action de l'algèbre de Hecke sur les symboles modulaires de Teitelbaum et sur les formes modulaires pour Fq[T]. Lorsque le degré de n est petit, on obtient des résultats non conditionnels : il n'existe aucun module de Drinfeld de rang 2 sur une extension de degré au plus 2 (resp. Au plus 3) de Fq(T) possédant un point de torsion d'ordre un idéal premier de degré 3 (resp. De degré 4 si q est au moins 7). Cela confirme partiellement une conjecture de Poonen et Schweizer de borne uniforme sur la torsion des modules de DrinfeldThis thesis studies the existence of torsion points of rank 2 Drinfeld modules over finite extensions of Fq(T) (q a prime power). Following the approach of Mazur and Merel for the torsion of elliptic curves over number fields, we introduce and study a quotient of the Jacobian of a Drinfeld modular curve, defined by a special Teitelbaum modular symbol. Under a hypothesis of duality between Hecke algebra and modular forms for Fq[T], and a minor technical hypothesis, we show the following result: if there exists a rank 2 Drinfeld module over an extension of degree at most q of Fq(T), with a torsion point of order a prime ideal n of Fq[T], then the degree of n is at most max(q, 4). For this purpose, we use a description of the action of the Hecke algebra on Teitelbaum modular symbols and on modular forms for Fq[T]. When n has small degree, we obtain unconditional results: there exists no rank 2 Drinfeld module over an extension of degree at most 2 (resp. At most 3) of Fq(T) with a torsion point of order a prime ideal of degree 3 (resp. 4 if q is at least 7). These statements partially confirm a conjecture of Poonen and Schweizer, about a uniform bound for the torsion of Drinfeld modules
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Kylat, Ranjit. "Neonatal testicular torsion: Is it time for consensus?" Wolters Kluwer - Medknow, 2017. http://hdl.handle.net/10150/625945.
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Testicular torsion (TT) occurring in the newborn period has been called neonatal
TT (NTT) or perinatal TT. Most of these are asymptomatic, occur prenatally,
and are difficult to diagnose. Almost all NTT are extravaginal. There is a lack
of consensus in the approach to management of this rare condition. An emergent
surgical exploration could salvage, the asymptomatic bilateral TT and prevent
asynchronous torsion. After a thorough review of the evidence, the conclusion
is that NTT should be managed like TT at any other age group, except that
nonoperative maneuvers may not be successful.
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SEBAG, FRANCK. "Instabilite de l'epaule et torsion de l'humerus." Aix-Marseille 2, 1993. http://www.theses.fr/1993AIX20052.
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Hesselmann, Sabine. "Zur Torsion der Kohomologie S-arithmetischer Gruppen." Bonn : [s.n.], 1993. http://catalog.hathitrust.org/api/volumes/oclc/31482302.html.
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Virili, Simone. "Group representations, algebraic dynamics and torsion theories." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/284141.
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La tesis está organizada en doce capítulos, divididos en cinco partes. La Parte I comprende los primeros tres capítulos. En el Capítulo 1 damos una breve introducción a la teoría de las categorías y recordamos las técnicas de las teorías de torsión y de la localización de categorías de Grothendieck. Empezamos el Capítulo 2 introduciendo la categoría de los "casi-frames" y estudiamos algunas construcciones básicas en esta categoría; en la segunda parte del capítulo estudiamos las dimensiones de Krull y de Gabriel de los casi-frames. Usando el hecho que los retículos de sub-objectos de un objeto dado en una categoría de Grothendieck es un casi-frame, podemos re-definir las nociones clásicas de dimension de Krull y de Gabriel para estos objetos. En el Capítulo 3 damos una breve introducción a los grupos y módulos topológicos. En particular, enunciamos el Teorema de Dualidad de Pontryagin-Van Kampen y el Teorema de Inversión de Fourier; además damos una demostración completa de un caso particular del Teorema de Dualidad de Müller entre módulos discretos y estrictamente linealmente compactos. Le Parte II está dedicada al estudio de la entropía en un contexto categórico. En el Capítulo 4 introducimos la categoría de los semigroupos pre-normados y la categoría de las T-representaciones de un monoide T sobre una categoría dada. Entonces definimos y estudiamos una función de entropía en la categoría de las T-representaciones sobre la categoría de los semigrupos pre-normados, con mayor énfasis en el caso en que T es un grupo amenable. En el Capítulo 5 damos ejemplos de invariantes clásicos que se pueden obtener de forma funtorial usando la entropía de semigrupos pre-normados definida en el capítulo anterior. Finalmente en el Capítulo 6 demostramos un Teorema Puente que relaciona la entropía topológica de acciones sobre grupos localmente compactos abelianos con la entropía algebraica de la acción sobre el grupo dual. En la Parte III estudiamos el problema de la extensión de las funciones de longitud a clases de módulos sobre productos cruzados utilizando la entropía. En particular, en el Capítulo 7 demostramos un teorema que describe la estructura de todas las funciones de longitud de una categoría de Grothendieck con dimensión de Gabriel. En el Capítulo 8 definimos y estudiamos la L-entropía algebraica de un RfiG-módulo M por la izquierda, donde R en un anillo general, G en un grupo amenable numerable y L es una función de longitud. En la Parte IV aplicamos la teoría desarollada a lo largo de la tesis a algunas conjeturas clásicas de la teoría de representaciones de grupos: la \Surjunctivity Conjecture", la \L-Surjunctivity Conjecture", la \Stable Finiteness Conjecture" y la \Zero-Divisors Conjecture". En el Capítulo 9 describimos las conjeturas y algunas relaciones entre ellas, inducidas por la dualidad de Müller. En el Capítulo 10 nos centramos en el caso amenable de las conjeturas, utilizando la entropía topologica para demostrar la Surjunctivity Conjecture para grupos amenables. Además explotamos la L-entropía algebraica para estudiar una versión general de la Stable Finiteness Conjecture y de la Zero-Divisors Conjecture. En el Capítulo 11 nos centramos en el caso sóficio de la L-Surjunctivity Conjecture y de la Stable Finiteness Conjecture, reduciendo ambas conjeturas a un enunciado más general sobre endomorfismos de casi-frames. Esto nos permite extender los resultados conocidos hasta ahora sobre las dos conjeturas. La Parte V está dedicada al estudio de aproximaciones de modelos para el algebra homológica relativa. En particular, aplicamos las herramientas desarrolladas en los Capítulos 1 y 2 para generalizar y re-interpretar algunos resultados recientes de Chachólski, Neeman, Pitsch, y Scherer.The thesis is organized in twelve chapters divided in five parts. Part I encompasses the first three chapters and consists mainly of background material. In Chapter 1 we provide the necessary background in general category theory and we recall the machinery of torsion theories and localization of Grothendieck categories. We start Chapter 2 introducing the category of quasi-frame and we study the basic constructions in this category. In the second part of the chapter we study the Krull and the Gabriel dimension of quasi-frames. Using the fact that the poset of sub-objects of a given object in a Grothendieck category is a quasi-frame, we re-obtain the classical notions of Krull and Gabriel dimension for such objects. In Chapter 3 we provide the necessary background in topological groups and modules. In particular, we state the Pontryagin-Van Kampen Duality Theorem and the Fourier Inversion Theorem, furthermore we give a complete proof of a particular case of the Mülcer Duality Theorem between discrete and strictly linearly compact modules. Part II is devoted to the study of entropy in a categorical setting. In Chapter 4 we introduce the category of pre-normed semigroups and the category of left T-representations of a monoid T over a given category. Then, we introduce and study an entropy function in the category of left T-representations over the category of normed-semigroups, with particular emphasis on the case when T is an amenable group. Chapter 5 consist of a series of examples of classical invariants that can be obtained functorially using the entropy of pre-normed semigroups. Finally, in Chapter 6 we prove a Bridge Theorem that connects the topological entropy of actions on locally compact Abelian groups to the algebraic entropy of the action induced on the dual group. Part III is devoted to the study of length functions and to apply the machinery of entropy to extend length functions to crossed products. Indeed, in Chapter 7 we prove a general structure theorem for length functions of Grothendieck categories with Gabriel dimension. In Chapter 8 we define the algebraic L-entropy of a left RfiG-module M, where R is a general ring and G is a countable amenable group and L is a suitable length function. In Part IV we apply the theory developed in the three previous parts to some classical conjectures in group representations: the Surjunctivity Conjecture, the L-Surjunctivity Conjecture, the Stable Finiteness Conjecture and the Zero-Divisors Conjecture. Using the Müller Duality Theorem we can clarify some relations among these conjectures. In Chapter 10 we concentrate on the amenable case of the above conjectures. In particular, we show how to use topological entropy to prove the Surjunctivity Conjecture for amenable groups and we use the algebraic L-entropy to study (general versions of) the Stable Finiteness and the Zero-Divisors Conjectures. In Chapter 11 we concentrate on the sofic case of the L-Surjunctivity and of the Stable Finiteness Conjectures. In particular, we reduce both conjectures to a more general statement about endomorphisms of quasi-frames. This allows us to generalize the known results on both conjectures. Finally, Part V is devoted to the study of model approximations for relative homological algebra. In particular, we apply the machinery introduced in Chapters 1 and 2 to extend and reinterpret some recent results of Chachfiolski, Neeman, Pitsch, and Scherer.
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Kong, Linggang. "Behaviour of pile groups subjected to torsion /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202006%20KONG.
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Stock, Sebastian [Verfasser]. "Evolution of Geometries with Torsion / Sebastian Stock." München : Verlag Dr. Hut, 2011. http://d-nb.info/1010446908/34.
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Truman, Christopher Brian. "Turaev torsion of 3-manifolds with boundary." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3453.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Mathematics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Barnes, J. A. "Torsion testing of filament wound composite cylinders." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382214.
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Tse, Mawuli I. (Mawuli Israel). "Ocular torsion during linear acceleration in space." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/83663.
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Porti, Joan. "Torsion de Reidemeister pour les variétés hyperboliques." Toulouse 3, 1994. http://www.theses.fr/1994TOU30193.
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On etudie une torsion de reidemeister pour les varietes de dimension trois, compactes, orientees et dont l'interieur admet une structure hyperbolique a volume fini. Lorsque la variete est close la representation adjointe de l'holonomie est acyclique, et donc la torsion associee a cette representation est un invariant topologique. Si le bord de la variete est un tore, pour chaque courbe simple fermee du bord on construit une fonction rationnelle sur la variete des caracteres. Les degenerescences euclidiennes des varietes coniques obtenues par chirurgie de dehn sur la variete correspondent a des zeros de cette fonction rationnelle
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Young, Alexander. "Validating Automotive Frame Torsion Stiffness Measurement Techniques." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470672143.
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Newman, J. Andrew. "Torsion in Homology of Random Simplicial Complexes." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531499208297615.
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Finski, Siarhei. "On some problems of holomorphic analytic torsion." Thesis, Sorbonne Paris Cité, 2019. https://theses.md.univ-paris-diderot.fr/FINSKI_Siarhei_va.pdf.
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Le but de cette thèse est d'étudier la torsion analytique dans deux contextes différents. Dans le premier contexte, on étudie l'asymptotique de la torsion analytique, quand un fibré vectoriel holomorphe hermitien est tordué par une puissance croissant du fibré en droites positif. Dans le deuxième contexte, on généralise la théorie de la torsion analytique pour des surfaces de Riemann avec des pointes hyperboliques. Motivé par des singularités de la métrique complète de courbure scalaire constante -1 sur des surfaces de Riemann stables épointées, on demande que la métrique sur la surface de Riemann soit lisse seulement en dehors d'un nombre fini des points au voisinage auxquelles elle peut avoir des singularités comme la métrique de Poincaré sur un disque épointé. On fixe un fibré vectoriel holomorphe hermitien qui peut avoir au pire des singularités logarithmiques au voisinage des points marqués. Pour ces données, en renormalisant la trace de l'opérateur de la chaleur, on construit la torsion analytique et on étudie ces propriétésIn the first context, we study the asymptotics of the analytic torsion, when a Hermitian holomorphic vector bundle is twisted by an increasing power of a positive line bundle. In the second context, we generalize the theory of analytic torsion for surfaces with hyperbolic cusps. Motivated by singularities appearing in complete metrics of constant scalar curvature -1 on stable Riemann surfaces, we suppose that the metric on the surface is smooth outside a finite number points in the neighborhood of which it can to have singularities like Poincaré metric has on a punctured disc. We fix a Hermitian holomorphic vector bundle which has at worst logarithmic singularities in the neighborhood of the marked points. For these data, by renormalizing the trace of the heat operator, we construct the analytic torsion and study its properties. Then we study the properties of the analytic torsion in family setting: we prove the curvature theorem, we study the behavior of the analytic torsion when the cusps are created by degeneration and we give some applications to the moduli spaces of pointed curves
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Légaut, Gédéon. "Ondes de torsion dans le noyau terrestre." Université Joseph Fourier (Grenoble), 2005. http://www.theses.fr/2005GRE10158.
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Le champ magnétique terrestre a des sources externes et internes à la Terre. Sur des échelles de temps décennales, ce champ présente des variations brusques: les "secousses géomagnétiques". Une des causes possibles aurait sa source dans le noyau de la Terre: les ondes de torsion. Après une introduction de ces ondes (ondes d'Alfvèn, équation d'onde), la propagation de ces ondes est étudiée dans un noyau avec ou sans graine. Enfin un mécanisme d'excitation d'origine externe à la Terre de ces ondes dans le noyau est étudié via les systèmes de courant de l'ionosphère et de la magnétosphèreEarth magnetic field is due to external and internal sources. On decennal time scale, this field has abrupt variations called "geomagnetic jerks". A possible explanation concerns Alfvèn magnetic waves in the liquid outer core. After introduction of these kind of waves (Alfvèn waves, wave equation), propagation of these kind of wave is studied in the outer core, with the presence or not of an solid inner core. Last, an excitation mecanism of external origin of these waves is studied
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Moreno, Agustin. "Algebraic Torsion in Higher-Dimensional Contact Manifolds." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/19849.
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Wir konstruieren Beispiele von Kontaktmannigfaltigkeiten in jeder ungeraden Dimension, welche endliche nicht-triviale algebraische Torsion (im Sinne von Latschev-Wendl) aufweisen, somit straff sind und keine starke symplektische Füllung haben. Wir beweisen, dass Giroux Torsion
algebraische 1-Torsion in jeder ungeraden Dimension impliziert, womit eine Vermutung von Massot-Niederkrüger-Wendl bewiesen wird. Wir konstruieren unendlich viele nicht diffeomorphe Beispiele von 5-dimensionalen Kontaktmannigfaltigkeiten, welche straff sind, keine starke
symplektische Füllung zulassen und keine Giroux Torsion haben. Wir erhalten Obstruktionen für symplektische Kobordismen, ohne für deren Beweis die SFT Maschinerie zu verwenden. Wir geben eine provisorische Definition eines spinalen offenen Buchs in höherer Dimension an, basierend auf der vom 3-dimensionalen Fall aus Lisi-van Horn Morris-Wendl. In einem Anhang geben wir in gemeinsamer Autorenschaft mit Richard Siefring eine wesentliche Zusammenfassung der Schnitttheorie für punktierte holomorphe Kurven und Hyperflächen an, welche die 3-dimensionalen Resultate von Siefring auf höhere Dimensionen verallgemeinert. Mittels der Schnitttheorie erhalten wir eine Anwendung für holomorphe Blätterungen von Kodimension zwei, die wir benutzen um das Verhalten von holomorphem Kurven in unseren Beispielen einzuschränken.We construct examples in any odd dimension of contact manifolds with finite and non-zero algebraic torsion (in the sense of Latschev-Wendl), which are therefore tight and do not admit strong symplectic fillings. We prove that Giroux torsion implies algebraic 1-torsion in any odd dimension, which proves a conjecture of Massot-Niederkrüger-Wendl. We construct infinitely many non-diffeomorphic examples of 5-dimensional contact manifolds which are tight, admit no strong fillings, and do not have Giroux torsion. We obtain obstruction results for symplectic cobordisms, for which we give a proof not relying on SFT machinery. We give a tentative definition of a higher-dimensional spinal open book decomposition, based on the 3-dimensional one of Lisi-van Horn Morris-Wendl. An appendix written in co-authorship with Richard Siefring gives a basic outline of the intersection theory for punctured holomorphic curves and hypersurfaces, which generalizes his 3-dimensional results to higher dimensions. From the intersection theory we obtain an application to codimension-2 holomorphic foliations, which we use to restrict the behaviour of holomorphic curves in our examples.
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Crossley, Julie Anne. "Elastic deformations of helically-wound composite cables." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246406.
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Ehlers, Hendrik Petrus. "Lag screw effect on the biomechanical torsion stability in the I.S.I monocortical mandible angle system." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/30368.
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In a recent in vitro biomechanical stability study by F.J. Jacobs, a unique, patented inclined screw insertion (I.S.I.) mandibular angle, intra-oral trauma-plate was evaluated for torsion and compression stability and compared to conventional plating of simulated angle fractures in polyurethane mandibular replicas. This in vitro comparative pilot study is an extension of the above-mentioned study. Similar I.S.I. mini-plates with 45º inclined screw holes in quadrant 3 (Fig 1), were used but in the one sample 13mm-long lag screws were used to transect the fracture lines where in the other group non-lagging screws of similar length were used to fixate simulated mandibular angle fractures in polyurethane mandible replicas. A uniquely designed and manufactured jig, incorporated in a Zwick machine, was utilized to apply torsion forces within clinical relevant load values. The load-displacement values for torsion forces was determined and compared for the two groups. It was established that 5 lag screws significantly improved the torsion stability of the lag-plate group to that of the non-lag group. During the stability testing, two factors were identified, which had a critical influence on the compression generated by the lag screw between the fracture fragments. An adequate amount of bone must be maintained between the first screw hole, directly distal to the fracture line, and the fracture line. All screws must be inserted in the correct sequence in order to insure sufficient compression between the fracture fragments as a result of the lag-effect. AFRIKAANS : In `n onlangse in vitro studie deur F.J. Jacobs, is `n gepatenteerde, unieke geanguleerde miniplate, waarvan die skroefgate geanguleer is, die sg. Inklineerde Skroef Inplasing (I.S.I.) kaak-hoek, intra-orale traumaplaat geevalueer vir torsie en kompressie stabiliteit en vergelyk met konvensionele plate op gesimuleerde kaakhoek frakture in poli-uretaan mandibular replikas. In hierdie in vitro loodstudie, is I.S.I. miniplate met skroefgate wat teen 45º geanguleer is, gebruik in kombinasie met `n enkele 13mm lange grypskroef (“lag screw”) om gesimuleerde kaakhoek frakture in poli-uretaan mandibula replikas te fikseer. Deur gebruik te maak van `n spesiaal ontwerpte en vervaardigde monterings-apparaat wat binne in `n Zwick masjien geïnkorporeer word, is die I.S.I gefikseerde replikas onderwerp aan torsie kragte, binne klinies relevante ladingswaardes. Die verplasings en ladingswaardes is geregistreer en vergelyk met identiese I.S.I miniplate sonder `n grypskroef. Die loodstudie resultate het getoon dat die frakture wat gefikseerd is met die I.S.I. miniplaat-grypskroef kombinasie betekenisvol beter stabiliteit toon as die frakture wat met slegs die miniplaat, sonder `n grypskroef, gefikseerd is vir klinies relevante ladingsen verplasingswaardes. Tydens biomeganiese toetsing van die mandibula replikas, is twee faktore wat `n kardinale rol speel in die stabiliteit wat verkry word deur `n miniplaat grypskroef kombinasie te gebruik, geïdentifiseer. Voldoende hoeveelheid been tussen die eerste skroefgat, direk distaal van die fraktuurlyn, en die fraktuurlyn asook die korrekte volgorde waarin die skroewe geplaas word, moet gehandhaaf word om maksimale kompressie van die fragmente deur die grypskroef te verseker. Deur `n I.S.I miniplaat, met geanguleerde skroefgate van 45º, te kombineer met `n grypskroef, kan die stabiliteit van die gefikseerde mandibulere kaakhoek betekenisvol verbeter word en verleen dit meer stabiliteit wanneer vergelyk word met frakture gereduseer met `n I.S.I miniplaat sonder grypskroef plasing.Dissertation (MSc)--University of Pretoria, 2010.
Maxillo-Facial and Oral Surgery
unrestricted
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Myklebust, Andreas. "Closed Loop System Identification of a Torsion System." Thesis, Linköping University, Department of Electrical Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17531.
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A model is developed for the Quanser torsion system available at Control Systems Research Laboratory at Chulalongkorn University. The torsion system is a laboratory equipment that is designed for the study of position control. It consists of a DC motor that drives three inertial loads that are coupled in series with the motor, and where all components are coupled to each other through torsional springs.
Several nonlinearities are observed and the most significant one is an offset in the input signal, which is compensated for. Experiments are carried out under feedback as the system is marginally stable. Different input signals are tested and used for system identification. Linear black-box state-space models are then identified using PEM, N4SID and a subspace method made for closed-loop identification, where the last two are the most successful ones. PEM is used in a second step and successfully enhances the parameter estimates from the other algorithms.
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Perin, Chloé. "Plongements élémentaires dans un groupe hyperbolique sans torsion." Phd thesis, Université de Caen, 2008. http://tel.archives-ouvertes.fr/tel-00460330.
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L'objet de cette thèse est d'obtenir une description des plongements élémentaires (au sens de la logique du premier ordre) dans un groupe hyperbolique sans torsion. Le résultat principal décrit ces plongements en terme d'une structure définie par Sela dans sa solution au problème de Tarski: la structure de tour hyperbolique. Ainsi, si H est plongé élementairement dans un groupe hyperbolique sans torsion G, on peut obtenir G en amalgamant successivement des groupes de surfaces à bord à un produit libre de H avec des groupes libres et des groupes de surfaces sans bord. Ceci permet en corollaire de montrer qu'un sous-groupe plongé élémentairement dans un groupe libre de type fini est un facteur libre. Les techniques utilisées pour obtenir cette description sont essentiellement géométriques: actions sur des arbres réels ou simpliciaux, existence de décompositions JSJ. On s'appuie également sur des résultats d'existence d'ensembles de factorisation qui affirment que pour certains groupes A de type fini, étant donné un groupe hyperbolique sans torsion G, il existe un ensemble fini de quotients de A tel que tout morphisme non injectif de A vers G se factorise par l'un de ces quotients après précomposition par un automorphisme de A. On expose une preuve de ces résultats, y compris une version complète et détaillée du shortening argument de Rips et Sela. Le shortening argument montre, grâce à l'analyse de Rips des actions sur des arbres réels, que si une suite d'action d'un groupe A sur des espaces hyperboliques converge vers un A-arbre réel d'un certain type, alors une infinité de ces actions peuvent être raccourcies.
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Wang, Zhihong. "Non-Einsteinian Interactions and Perturbative Gravitation with Torsion." Thesis, Lancaster University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485255.
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The main aim of this thesis is to investigate non-Einsteinian interactions in a scalartensor theory and a tensor-tensor theory of gravity with torsion. We first explore perfect fluid and spinning particle dynamics in a scalar-tensor theory of gravity with scalar field interactions, and derive equations of motion for a charged perfect fluid both from gauge identities and a variational principle in background nonRiemannian spacetime (metric compatible connection with torsion), a scalar field and an electrom(l.gnetic field. For a spinning particle, we use gauge identities with given source currents to obtain its equations of motion with scalar field interactions, and solve its equations of motion in two different backgrounds: one is a BransDicke torsion field and the other is a constant pseudo-Riemannian curvature with constant scalar field and zero torsion. Moreover, we calculate the precession of a gyroscope moving along abound orbit in the weak limit of a vacuum Kerr-BransDicke solution with torsion. In Chapter 4, the equations of motion for massive spinless particles in a tensor-tensor theory of gravity with torsion are investigated. We first apply the perturbation scheme to the system of field equations and discover a perturbed torsion wave solution. Furthermore, we obtain gauge transformations of perturbed field variables and examine the polarizations of this torsion wave solution from autoparallel deviation. The longitudinal modes of the torsion wave polarization has been found. The polarizations (both transverse and longitudinal modes) of the torsion wave are quite different from the gravitational wave in the linearized GR.
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Hussain, Hyder. "Torsion fatigue system for mechanical characterization of materials." Ohio : Ohio University, 2000. http://www.ohiolink.edu/etd/view.cgi?ohiou1172002877.
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Cramer, Claire E. "A torsion balance search for spin-coupled forces /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/9764.
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Pfäffle, Frank, and Christoph A. Stephan. "On gravity, torsion and the spectral action principle." Universität Potsdam, 2012. http://opus.kobv.de/ubp/volltexte/2012/5998/.
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We consider compact Riemannian spin manifolds without boundary equipped with orthogonal connections. We investigate the induced Dirac operators and the associated commutative spectral triples. In case of dimension four and totally anti-symmetric torsion we compute the Chamseddine-Connes spectral action, deduce the equations of motions and discuss critical points.
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Mati, Ioulia. "Molecular torsion balances for quantifying non-covalent interactions." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7610.
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Non-covalent interactions underpin the whole of chemistry and biology, but their study is extremely difficult in complicated biological systems. This thesis presents the application of synthetic molecular balances for gaining fundamental insights into the physicochemical phenomena that govern molecular recognition processes. Chapter 1 reviews the use of small synthetic molecules that exist in two conformational states via slow rotation of a bond, in the quantification of non-covalent interactions. Chapter 2 presents a new molecular torsion balance, based on a slowly rotating tertiary formyl amide for the study of non-covalent interactions. The incorporation of a fluorine atom in one of the rings allows the quantification of solvent effects in a wide range of solvents. Intramolecular electrostatic interactions and intermolecular solvation effects (but not solvophobic effects) are shown to be important in determining the position of the conformational equilibria. Correlations with calculated molecular properties show that solvent effects are fully dissected, revealing the idealistic behavior of the system in the gas phase. Chapter 3 discusses through-space substituent effects on the properties of aromatic rings. Electronic communication between both electron-rich and electron-deficient substituents with the electron density of an adjacent aromatic ring is predicted by molecular electrostatic potential calculations. The effect is confirmed to occur experimentally and is quantified using synthetic molecular balances. Chapter 4 describes the work done towards the investigation of solvent bridging interactions in molecular torsion balances. No experimental evidence of bridging interactions was observed. This might be attributed to the entropic penalty associated with this binding mode, or the non-ideal geometry of the potential bridging sites. Chapter 5 outlines a steric blocking effect observed in certain balances with bulky substituents in chloroform and dichloromethane. Chapter 6 presents synthetic procedures and compound characterisation including a thorough analysis of NMR data obtained in this study.
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Kobayashi, H. "Shear localization and fracture in torsion of metals." Thesis, University of Reading, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374880.
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