Tesi sul tema "Fibres de Springer"
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Chen, Zongbin. "Pureté des fibres de Springer affines pour GL_4". Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112266/document.
This thesis consists of two parts. In the first part, we prove the purity of affine Springer fibers for $\gl_{4}$ in the unramified case. More precisely, we have constructed a family of non standard affine pavings for the affine grassmannian, which induce an affine paving for the affine Springer fiber. In the second part, we introduce a notion of $\xi$-stability on the affine grassmannian $\xx$ for the group $G=\gl_{d}$, and we calculate the Poincaré polynomial of the quotient $\xx^{\xi}/T$ of the stable part $\xxs$ by the maximal torus $T$ by a process analogue to the Harder-Narasimhan reduction
Chen, Zongbin. "Sur la pureté des fibres de Springer affines non-ramifiées pour GL4". Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00656163.
Fresse, Lucas. "Une étude combinatoire de la géométrie des fibres de Springer de type A". Lyon 1, 2007. http://www.theses.fr/2007LYO10322.
The variety of flags which are stable by a nilpotent endomorphism is called Springer fiber. We study this variety and its irreducible components. The fixed points of a torus on this variety are parameterized by a set of tableaux said row-standard. We construct a cell decomposition of the variety which is naturally parameterized by the row-standard tableaux, since each cell contains one fixed point, and such that the codimension of cells is analogous to a Bruhat length. This allows a handy calculation of the Betti numbers. When the nilpotent endomorphism is of hook, two-rows or two-columns type, we define a notion of constructibility for the row-standard tableaux which allows to describe the fixed points of the components. We deduce a calculation of the dimension of a finite intersection of components and, in the two-columns case, a criterion of singularity
Jacques, Simon. "Adhérences de certaines orbites dans la variété de drapeaux, résolution et normalité dans les types classiques A, B, D". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0299.
Let G be a connected algebraic reductive group in types A, B, or D, and e be a nilpotent element of its Lie algebra with centralizer Z:=Z_G(e). We suppose the characteristic zero and that e corresponds to a nilpotent endomorphism of order two. We sketch a proof of the following result: all Z-orbit closures Y in the flag variety X of G are normal. It extends a work of Nicolas Perrin and Evgeny Smirnov which deals with an irreducible component Y of the Springer fiber X(e) in types A and D. We use the same main arguments, namely an induction based on (1): the existence of a suitable birational morphism onto Y, and (2): the surjectivity of section restrictions of an ample line bundle. For us (1) will be obtained thanks to good Weyl group elements, Schubert varieties, Bott-Samelson varieties and several fundamental results from Roger Wolcott Richardson and Tonny Albert Springer on symmetric spaces. On the other hand, (2) follows from a theorem proved by Xuhua He and Jesper Funch Thomsen which states Frobenius splittings of Y-like varieties. It thus implies (2) in positive characteristic and we just have to pass it through the zero : we then merely produce an example of the reduction modulo p method.Our work suggests several avenues of research and could be improved in several directions. It could have implications for the study of the irreducible components of the Steinberg variety and thus for the calculation of the characteristic polynomials. They have been introduced by Anthony Joseph in order to constitute irreducible representations of the Weyl group. Our work also raises the question of its generalization to the C type, the exceptional types and the positive characteristic
Bouthier, Alexis. "Géométrisation du côté orbital de la formule des traces". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112064.
This main goal of this work is to construct and study the properties of Hitchin fibration for groups which appears naturally when we try to geometrize the trace formula. We begin by constructing this fibration using the Vinberg’s semigroup. On this semigroup, we show that there exists a characteristic polynomial morphism equipped with a natural section, analog at the Kostant’s one in the case of Lie algebras. We also show that there exists on the base of characteristic polynomials a regular centralizer scheme, which is a smooth commutative group scheme.Then, we are interested in some variant of affine Springer fibers, for which we see that the Vinberg’s semigroup appears naturally to obtain an integrality condition analog to Kazhdan-Lusztig’s one. These affine Springer fibers are local incarnation of Hitchin fibers.In a third time, we go back to the global case and give a modular interpretation of this new Hitchin fibration on which we construct an action of a Picard stack, coming from the regular centralizer.The total space of this fibration, even on the generically regular semisimple locus will be singular and we want to understand his intersection complex. This space can be obtained as the intersection of the Hecke stack with the diagonal of the stack of G-bundles and we show that on a sufficiently big open subset of the Hitchin base, the intersection complex of the Hitchin’s space is the restriction of the corresponding intersection complex on the Hecke stack.Finally, in the last part of this work, we establish a support theorem in the case of a singular total space, generalizing Ngo’s theorem et we show that in the case of Hitchin fibration, the supports that appear are related to the endoscopic strata
Yue, Guangyi. "Combinatorics of affine Springer fibers and combinatorial wall-crossing". Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/126939.
Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 149-152).
This thesis deals with several combinatorial problems in representation theory. The first part of the thesis studies the combinatorics of affine Springer fibers of type A. In particular, we give an explicit description of irreducible components of Fl[subscript tS] and calculate the relative positions between two components. We also study the lowest two-sided Kazhdan-Lusztig cell and establish a connection with the affine Springer fibers, which is compatible with the affine matrix ball construction algorithm. The results also prove a special case of Lusztig's conjecture. The work in this part include joint work with Pablo Boixeda. In the second part, we define the combinatorial wall-crossing transformation and the generalized column regularization on partitions and prove that a certain composition of these two transformations has the same effect on the one-row partition. This result gives a special situation where column regularization, can be used to understand the complicated Mullineux map, and also proves a special case of Bezrukavnikov's conjecture. Furthermore, we prove a condition under which the two maps are exactly the same, generalizing the work of Bessenrodt, Olsson and Xu. The combinatorial constructions is related to the Iwahori-Hecke algebra and the global crystal basis of the basic [ ... ]-module and we provide several conjectures regarding the q-decomposition numbers and generalizations of results due to Fayers. This part is a joint work with Panagiotis Dimakis and Allen Wang.
by Guangyi Yue.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mathematics
Wilbert, Arik [Verfasser]. "Two-row Springer fibers, foams and arc algebras of type D / Arik Wilbert". Bonn : Universitäts- und Landesbibliothek Bonn, 2017. http://d-nb.info/113904897X/34.
Boixeda, Alvarez Pablo. "Affine Springer fibers and the representation theory of small quantum groups and related algebras". Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/126920.
Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 125-128).
This thesis deals with the connections of Geometry and Representation Theory. In particular we study the representation theory of small quantum groups and Frobenius kernels and the geometry of an equivalued affine Springer fiber Fl[subscript ts] for s a regular semisimple element. In Chapter 2 we relate the center of the small quantum group with the cohomology of the above affine Springer fiber. This includes joint work with Bezrukavnikov, Shan and Vaserot. In Chapter 3 we study the geometry of the affine Springer fiber and in particular understand the fixed points of a torus action contained in each component. In Chapter 4 we further have a collection of algebraic results on the representation theory of Frobenius kernels. In particular we state some results pointing towards some construction of certain partial Verma functors and we compute this in the case of SL₂. We also compute the center of Frobenius kernels in the case of SL₂ and state a conjecture on a possible inductive construction of the general center.
by Pablo Boixeda Alvarez.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mathematics
Fan, Xiuling Broughton Roy. "Value-added products from chicken feather fibers and protein". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SPRING/Polymer_and_Fiber_Engineering/Dissertation/Fan_Xiuling_15.pdf.
Llimpe, Rojas Jorge Enrique. "Theoretical and practical approaches for novel composite evolute springs". Master's thesis, Pontificia Universidad Católica del Perú, 2018. http://tesis.pucp.edu.pe/repositorio/handle/123456789/11172.
Tesis
Liu, Yang. "Calibration of Glass Fiber Microcantilevers". Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1268336942.
Rueckert, Cheryl B. "Evaluation of preferential energy absorption in earlywood and latewood fibers of loblolly pine in cyclic compression". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/5805.
Taylor, Robert Paul. "Finite Element Analysis of the Application of Synthetic Fiber Ropes to Reduce Seismic Response of Simply Supported Single Span Bridges". Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34051.
Master of Science
Lingnau, Werner August Leonhard. "Substitution of maize with high fibre by-products in concentrates supplemented to dairy cows grazing kikuyu/ryegrass pasture during spring". Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6459.
ENGLISH ABSTRACT: Kikuyu over-sown with ryegrass forms the basis of pasture based systems in the Southern Cape. During early spring, energy is the first limiting nutrient in kikuyu/ryegrass pasture, supplementation is thus essential. Supplementation consists mainly of high starch concentrates (high maize inclusion), which is expensive and could negatively affect rumen parameters. The objective of this study was to determine if milk production could be improved or maintained, and if the rumen environment would be improved, by replacing high starch concentrates with low starch (high by-product) concentrates for dairy cows on kikuyu/ryegrass pasture. Forty-five multiparous, high producing, lactating Jersey cows [body weight, 340 ± 34.7 kg; milk yield (MY), 19.6 ± 2.23kg/d; days in milk (DIM), 153 ± 33.5; lactation number, 3.6 ± 1.85; (mean ± SD)] were used in the production study. A randomised block design was used. The forty-five cows were allocated to fifteen groups of three each (blocking) on the basis of MY, DIM, and lactation number. Cows from each group were randomly allocated to one of three treatment groups (high starch, medium starch and low starch concentrate supplementation). Cows were fed 6kg (3kg during each milking) concentrate per day and were allocated fresh pasture ad lib after each milking. There were no significant differences (P > 0.05) found in milk yield and fat corrected milk yield between treatment groups. Milk fat percentage was significantly higher (P < 0.05) in the low starch treatment than in the high starch treatment. Milk fat yield was significantly higher (P < 0.05) in both the low starch and the medium starch treatment when compared to the high starch treatment. Milk protein and lactose percentages, as well as milk urea nitrogen and somatic cell count, did not differ significantly (P > 0.05) between treatments. Live weight change, as well as body condition score change, was unaffected (P > 0.05) by treatments indicating body reserves were not used to maintain milk production in the low starch treatment. A rumen metabolism study was also done with ten lactating, cannulated Jersey cows [body weight, 332 ± 56.3 kg; MY, 17.3 ± 1.73kg/d (mean ± SD)] were used. The cows were divided into two groups of five each, on the basis of lactation number, DIM, and MY. The five cows from each group were randomly allocated to one of two treatment groups (high starch and low starch concentrate supplementation) and used in a cross-over design. Cows were fed 6kg concentrate per day and were allocated fresh pasture ad lib after each milking. The volatile fatty acid (VFA) concentration was significantly higher (P < 0.05) in the high starch treatment when compared to the low starch treatment. The individual VFA’s, acetic-, propionic- and butyric acid concentrations were also significantly higher (P < 0.05) in the high starch treatments when compared to the low starch treatment. The acetic to propionic acid ratio was unaffected (P > 0.05) by treatment. Rumen ammonia-nitrogen concentration was significantly higher (P < 0.05) in the high starch treatment. Rumen pH was unaffected (P > 0.05) by supplementation type. The in sacco dry matter and neutral detergent fibre digestibilities of the kikuyu/ryegrass pasture were unaffected (P > 0.05) by treatment type. Results indicated that milk production could be maintained with low starch concentrates which also improved milk composition. Results further suggested that the rumen environment was relatively unaffected by low starch concentrate supplementation.
AFRIKAANSE OPSOMMING: Kikoejoe, oorgesaai met raaigras, vorm die basis van weidingstelsels in the Suid-Kaap. Tydens die lentemaande is energie die eerste beperkende voedingstof op kikoejoe/raaigras weidings, wat kragvoeraanvulling noodsaaklik maak. Aanvulling bestaan grootliks uit hoëstysel-kragvoer (hoë mielieinhoud) wat nie net duur is nie, maar dit kan ook die rumenomgewing benadeel. Die doel van die studie was om vas te stel of melkproduksievlakke onderhou kan word en of rumenomgewing verbeter kan word deur die vervanging van hoëstysel-kragvoer met laestysel-kragvoer (hoë neweprodukinhoud) vir melkkoeie op kikoejoe/raaigras weidingstelsels. Vyf-en-veertig meervoudige pariteit-, hoë produserende, lakterende Jerseykoeie [liggaamsmassa, 340 ± 34.7 kg; melkproduksie, 19.6 ± 2.23kg/d; dae in melk, 153 ± 33.5; laktasienommer, 3.6 ± 1.85; (gem ± standaardafwyking)] is gebruik vir die produksiestudie van die proef. Daar is gebruik gemaak van ‘n ewekansige blokontwerp. Die vyf-en-veertig koeie is opgedeel in vyftien groepe van drie elk, gebaseer op melkproduksie, dae in melk en laktasienommer. Koeie in elke groep is ewekansig aan een van drie behandelings (hoëstysel-, mediumstysel- of laestysel-kragvoeraanvulling) geallokeer. Koeie is daagliks 6kg (3kg tydens twee milkings) kragvoer gevoer en vars weiding was ad lib beskikbaar na elke melking. Daar was geen beduidende verskil (P > 0.05) in melkopbrengs of vet-gekorrigeerde melkopbrengs tussen die drie behandelings nie. Bottervetpersentasie was beduidend hoër (P < 0.05) in die laestyselbehandeling in vergelyking met die hoëstyselbehandeling. Bottervetopbrengs was beduidend hoër (P < 0.05) in beide die laestysel- en mediumstyselbehandelings in vergelyking met die hoëstyselbehandeling. Melkproteïen- en melklaktosepersentasies, asook melkureumstikstof en somatise seltelling, was onveranderd (P > 0.05) tussen behandelinge. Liggaamsmassa en liggaamskondisietelling het geen verskille (P > 0.05) getoon tussen behandelings nie, wat daarop dui dat liggaamsreserwes nie gebruik is om melkproduksie in die laestyselbehandeling te onderhou nie. ‘n Rumenmetabolismestudie is ook uitgevoer met tien lakterende, gekannuleerde Jerseykoeie [liggaamsmassa, 332 ± 56.3 kg; melkproduksie, 17.3 ± 1.73kg/d (gem ± standard afwyking)]. Die koeie is in twee groepe van vyf elk verdeel, gebasseer op laktasienommer, dae in melk en melkproduksie. Die vyf koeie van elke groep is in ‘n omslagontwerp gebruik en is ewekansig aan een van twee behandelings (hoëstysel- of laestysel-kragvoeraanvulling) geallokeer. Koeie het daagliks 6kg kragvoer ontvang en vars weiding was ad lib beskikbaar na elke melking. Die vlugtige vetsuurkonsentrasie was beduidend hoër (P < 0.05) in die hoëstyselbehandeling as in die laestyselbehandeling. Die individuele vlugtige vetsure naamlik asynsuur, propionsuur en bottersuur, was ook beduidend hoër (P < 0.05) in die hoëstyselbehandeling as in die laestyselbehandeling. Die asynsuur- tot propionsuurverhoudings het geen verskille (P > 0.05) tussen behandelings getoon nie. Rumen-ammoniakstikstof was beduidend hoër (P < 0.05) in die hoëstyselbehandeling as in die laestyselbehandeling. Rumen-pH het geen verskille (P > 0.05) getoon tussen behandelings nie. Die in sacco droëmateriaal- en neutraalbestande veselverteerbaarhede van kikoejoe/raaigras weiding het geen verskille (P > 0.05) tussen behandelings getoon nie. Die resultate het aangedui dat melkproduksie onderhou kan word en dat melksamestelling verbeter kan word met laestysel-kragvoeraanvulling. Resultate het ook daarop gedui dat die rumenomgewing nie noodwendig verbeter word deur die aanvulling van laestysel-kragvoer vir koeie op kikoejoe/raaigras weidings nie.
Motley, Michael Rembert. "Finite Element Analysis of the Application of Synthetic Fiber Ropes to Reduce Blast Response of Frames". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/36155.
Finite element models of portal frames were developed using the commercial finite element program ABAQUS and dynamic models were run for varying blasts and frame systems. Blast pressures of 100, 2,000, and 4,000 psi were applied to a steel portal frame and comparisons were made between unbraced frames and frames braced with springs of different stiffnesses. Additional tests were run to examine the effects of strain rate dependent yield on the results of the models. Parallel research is being conducted on the specific material behavior of the synthetic fiber ropes so that the models developed for this research can be revised for a more accurate determination of the effects of the ropes on structural systems subjected to blast loads.
Master of Science
Mao, Huina. "Numerical and Experimental Studies of Deployment Dynamics of Space Webs and CubeSat Booms". Doctoral thesis, KTH, Farkost och flyg, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206594.
QC 20170508
SEAM
Верещага, Б. А. "Дослідження впливу технології виготовлення, складу ламінату, термічної обробки на фізико-механічні властивості полімерної, композитної пластинчастої пружини". Master's thesis, Сумський державний університет, 2021. https://essuir.sumdu.edu.ua/handle/123456789/86489.
Chiu, Chun-Kai, e 邱俊凱. "Impact and Damping Properties of Braided Composite Spiral Spring with Different Fibres". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/69769891638446312922.
逢甲大學
紡織工程所
94
In this experiment, composite spiral springs were made with three kinds of fibre prepreg i.e carbon fibres, kevlar fibres and E-glass fibres. Different kinds of cured springs were then assembled as respective shock absorber systems and their performance such as the compression load under 1-in deformation, the damping properties of assembled absorber system and the lateral impact resistance were explored. The experimental results show that the composite spring made of carbon / E-glass composition structure can gain the highest compression load under 1-in deformation with no damage occurred in the body of the spring. For the carbon / E-glass composition is 50% to 50%, the maximum compression load of the spring can be 470 lb/in with a maximum deformation of 1.6 in. As far as the damping properties are concerned, the absorber system composed of half to half carbon and E-glass fibres will be able to obtain the best damping performance, which fits to an economic and practical consideration. With the same composition of carbon and E-glass fibres, composite springs can also have higher energy absorption, which means c50g50 composition will be the ideal structure of the shock absorber system applied on bike.
Li, Yung-yi, e 李勇圻. "The Compression and Fatigue Effect of Different Fibers of Braided Composite Sprial Spring". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/61947133942376055337.
逢甲大學
紡織工程所
94
In this thesis, composite springs were made of different fiber prepreg .ie carbon fibers, E-glass fibers and Kevlar 49 fibers, with relevant mechanical sprig constant (K) and fatigue tested after parts cured. According to the experimental results, the structure of composite springs mixed with carbon fibers and glass fibers have the higher load per unit compression displacement which is better than other composition. After comparing with other structures, the C50G50 structure of spiral spring has good properties with more cost effective. Its load per unit compression displacement reaches 469.3 lb/in and the displacement is 1.590 in. Fatigue resistance was tested by fixing compression displacement, which was set as 70 percent of maximum compression displacement of the composite spring with 300,00times a cycle. Based on the fatigue test, the decreases of load during fatigue test are both in the range of 5 percent for the springs made of carbon fibers and glass fibers (C50G50, C30G70) and the sprigs made of high modulus carbon fibers and glass fibers (HC50G50, HC30G70).
Huang, Tzu-Yu, e 黃子瑜. "Multiferroic fibrous composites with spring-type imperfect interface : Generalized plane problem". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/k24zba.
國立交通大學
土木工程系所
103
This research studies the effective properties and magneto-electric (ME) coupling of piezoelectric-piezomagnetic fibrous composites with mechanically compliant and weakly electromagnetic conducting interface under generalized plane strain with transverse electromagnetic fields. In this case, we assume that the displacement and potential have a jump across the interface and proportional to the normal components of the stress, electric displacement and magnetic flux density. The closed-form formula of the effective properties is obtained by using the complex variable approach and adopting micromechanical models. The numerical results obtained from different methods are shown in agreement, while the result of ad hoc approximation of C11 、C12 and (C11-C12)/2 is only correct for the interface condition of slightly weakened. The results obtained from the Mori-Tanaka method and the two-level recursive scheme show that the imperfect effect is equivalent to a three-phase composite. Due to the interface imperfection, the maximum magnetoelectric voltage coefficients become 0.0048V/cmOe (BTO/CFO,fi=0.147) and 0.0038V/cmOe (CFO/BTO,fi=0.91), which decrease by 190 times and 260 times compared to the case of perfect interface. Finally, we also study the size-dependent effect numerically.
(7043354), Himal Agrawal. "Manufacturing and Testing of Composite Hybrid Leaf Spring for Automotive Applications". Thesis, 2019.