1,863 research outputs found
Stability approach for periodic delay Mathieu equation by the He- multiple-scales method
No full textIn the present work, the version of homotopy perturbation included time-scales is applied to the governing equation of time-periodic delay Mathieu equation. Periodical structure for the amplitude of the zero-order perturbation is constructed. The stability analysis is accompanied by considering three-time-scales. Approximate periodic solutions are derived to the second accuracy of perturbations at the harmonic resonance case as well as at the non-harmonic resonance case. Stability conditions are derived in both cases. Numerical calculations have been done to illustrate the stability behavior at both resonance and non-resonance case. It is shown that the time-delay has a destabilizing influence. We note that the delayed of the parametric excitation has a great interested and application to the design of nuclear accelerators. Keywords: Homotopy perturbation method, Multiple-scales perturbation, Periodic delay Mathieu equation, Parametric resonance, Stability analysi
Modeling the Synchrotron: An Exploration of Delay-Coupled Nonlinear Mathieu Equations
No full textA synchrotron is a circular particle accelerator where beams of electrons are maintained at high velocity. Each beam contains clusters of electrons called ``bunches,'' and we model the vertical displacement of each bunch as simple harmonic motion with parametric excitation, i.e. the Mathieu equation. Different types of coupling are accounted for, including one that only takes effect after one orbit, which we model using delay terms; the resulting model is a system of delay-differential equations. Nonlinear and damping terms are also included to make the model more realistic and the dynamics more rich. Variations of this core model are examined using perturbation methods and checked against numerical integration
Analysis of Mathieu Equation Stable Solutions in the First Zone of Stability
No full textAbstractThe paper presents the results of a homogeneous Mathieu equation studies. Mathieu equation solutions are oscillations, modulated in amplitude and frequency. In the computational experiments we found dependences of the given oscillations on the ratio of the coefficients. These dependences are shown in graphs that can be used for an approximate estimation of the Mathieu equation solutions without integration
Pensar las escalas para pensar las luchas: Autor: Mathieu UHEL
No full textA través de un título sugerente, “pensar las escalas para pensar las luchas”, Mathieu Uhel entreteje la construcción teórico-crítica del concepto escala, generada por la geografía radical anglosajona de finales del siglo XX, con la necesidad/utilidad práctica de la escala para concienciar las luchas sociales. El artículo cumple un doble propósito: por un lado, delinear los elementos de lectura sobre el concepto escala; y, con ello, promover la atención de esta problemática en las luchas contemporáneas. En un primer apartado, Uhel ubica las discusiones académicas en torno a la escala, como herramienta metodológica útil para comprender la complejidad de las sociedades capitalistas; en el segundo apartado, el autor avanza la exposición en torno al contexto de la dimensión escalar del imperialismo capitalista; finalmente, el autor se centra en el rol de la actividad política a escala nacional en la tensa relación entre las imposiciones del capital y la lucha social.Por meio de um título sugestivo, “pensando escalas para pensar lutas”, Mathieu Uhel entrelaça a construção teórico-crítica do conceito de escala, gerado pela geografia radical anglo-saxônica do final do século XX, com a necessidade / utilidade prática escala para aumentar a consciência das lutas sociais. O artigo tem um duplo propósito: por um lado, delinear os elementos de leitura sobre o conceito de escala; e, com isso, promover atenção a esse problema nas lutas contemporâneas. Na primeira seção, Uhel localiza as discussões acadêmicas em torno da escala, como uma ferramenta metodológica útil para compreender a complexidade das sociedades capitalistas; na segunda seção, o autor avança a exposição em torno do contexto da dimensão escalar do imperialismo capitalista; por fim, o autor enfoca o papel da atividade política em escala nacional na tensa relação entre as imposições do capital e a luta social.Mathieu Uhel\u27s suggestive title, “Thinking about scales to think about struggles”, he interweaves the theoretical-critical construction of concept scale, generated by radical Anglo-Saxon geography in the late 20th century, with it´s practical utility to social struggles. The article serves two purposes: on the one hand, Uhel locates academic discussion around scale; and, with this, he promotes attention to this problem in contemporary struggles. In the first section, Uhel locates academic discussions around scale, as a useful methodological tool to understand the complexity of capitalist societies; in the second section, the author advances the argument around the context of the scalar dimension of capitalist imperialism; finally, the author focuses on the role of political activity on a national scale in the tense relationship between the impositions of capital and the social movement
Renormalization group methods for a Mathieu equation with delayed feedback
No full textAbstractThis paper presents the application of the renormalization group (RG) methods to the delayed differential equation. By analyzing the Mathieu equation with time delay feedback, we get the amplitude and phase equations, and then obtain the approximate solutions by solving the corresponding RG equations. It shows that the approximate solutions obtained from the RG method are superior to those from the conventionally perturbation methods
Mathieu Ichou, Les Enfants d’immigrés à l’école
No full textIt is common to hear in the fields of educational and immigration sociology that on average, the children of immigrants do not perform as well in school as children of native-born parents. Mathieu Ichou offers an innovative sociological analysis on a topic that is heavily exploited by political and media discourse, and subject to much scientific controversy. The author takes distance from the homogenized vision of a “second generation” of students who have totally failed academically, and rep..
J’ suis assuré ou le cabinet Piperlin : chansonnette créée par [Émile] Mathieu à l’Eldorado [illustration Émile Butscha (1847-1887)]
No full textJ’ suis assuré ou le cabinet Piperlin : chansonnette créée par Mathieu à l’Eldorado [Émile Mathieu] ; illustration signée Émile Butscha (1847-1887) ; paroles de Villemer & Delormel ; musique de Charles Pourny ; Paris, L. Labbé éditeur [Louis Labbé (1839-1924)] ; [intérieur : mentions identiques (artiste et lieu ) ; Maison L. Vieillot L. Labbé éditeur ; cotage LV6536 6537 ; imprimerie Delay] ; verso vierge ; incipit : “Piperlin, un d’ mes bons amis”. Datation (titre) : 1881, par dépôt légal FRBNF43214444 (la notice BNF ne précise pas si l’exemplaire conservé est illustré par Butscha)
Time delayed piecewise linear Mathieu equation: an analytical and numerical study
No full textIn this study, we consider analytical and numerical exploration of the dynamics of a weakly nonlinear piecewise linear (PWL) Mathieu equation with a time delay. A study of such dynamical systems requires finding the time instants of crossing between the two linear states. Moreover, the time delay further complicates the system dynamics by making it infinite-dimensional. In this study, we employ the method of averaging, incorporating non-analytic PWL basis functions along with corresponding algebraic techniques. This approach enables the application of the method of averaging to the resonantly forced, essentially nonlinear PWL Mathieu equation. We herein show that the amplitude evolution and the bifurcation exhibited by the periodic solutions are very well captured by the method of averaging and is a potent tool in studying this class of dynamical systems
L'impatto dell'attività tintoria sull'ambiente. Firenze alla fine del Medioevo
No full textThe author aims to examine and categorize the range of dyeings materials used in the Florentine wool and silk textile industries in the late Middle Ages, focusing mainly on those produced within the regional space in order to evaluate the impact of the Florentine dyeing activity on the natural environment and the productive landscape of the Tuscan countryside. In particular, the author establishes a line of demarcation between cultivated and uncultivated resources in order to verify which constitutes an indication of the level of industrial development of medieval textile production. This further focuses on how the transition from the exploitation of wild resources to the exploitation of cultivated resources could reflect a greater degree of economic integration between the countryside and the city and contribute to the formation of a regional economic space
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