Results 221 to 230 of about 2,194,446 (266)

First-Order Variational Principles

2017
In the previous chapter we addressed zeroth-order variational principles rooted in the fundamental principle of d'Alembert. In this chapter we will focus on the first-order variation of displacement. We will begin with Jourdain's Principle of Virtual Power (Jourdain 1909). The principle is based on the notion of virtual velocity.
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Circadian and seasonal variation of first febrile seizures

The Journal of Pediatrics, 2004
Time of occurrence of 188 first febrile seizures (FS) was recorded, both by four 6-hour periods and by hourly intervals. The frequency of events was significantly ( P < .001) increased from 6 to 11.59 pm with a peak between 5 and 8 pm . A seasonal peak was observed in January.
MANFREDINI, Roberto, VERGINE, Gianluca, BOARI, Benedetta, FAGGIOLI, Raffaella, BORGNA, Caterina   +4 more
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On a Crystalline Variational Problem, Part I:¶First Variation and Global L∞ Regularity

Archive for Rational Mechanics and Analysis, 2001
Let φ:ℝ n → [0,+∞[ be a given positively one-homogeneous convex function, and let ?φ≔{φ≤ 1 }. Pursuing our interest in motion by crystalline mean curvature in three dimensions, we introduce and study the class ?φ (ℝ n ) of “smooth” boundaries in the relative geometry induced by the ...
Bellettini G., NOVAGA, MATTEO, Paolini M.   +2 more
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First-Stage Design Variations of Partially Reusable Launch Vehicles

Journal of Spacecraft and Rockets, 2001
This paper investigates different types of reusable first stages designed for a near term application with heavy lift launchers. The attached reference expendable space transportation system is a future Ariane 5 with cryogenic core and upper stage, but skipped solid rocket boosters.
Sippel, M., Atanassov, U., Klevanski, I., Schmid, V.   +3 more
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First Mathematical Interlude: Variational Calculus

2015
Many problems in statistical mechanics require minimizing a free energy not just over one variable, or even several variables, but over a function. Variational calculus is the mathematical method for performing such minimizations. This chapter presents the mathematical technique of variational calculus, with examples in classical mechanics.
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First variation formula for discrete variational problems in two independent variables

Revista de la Real Academia de Ciencias Exactas, Fisicas y Naturales. Serie A. Matematicas, 2011
The authors introduce a geometric setup for discrete variational problems in two independent variables, which is based on the theory of bundles modelled on cell complexes. Using this approach, geometrical characterizations of the first variation formula (see Theorem 2) and the Discrete Noether theorem (see Theorem 4) are given.
Casimiro, Ana Cristina, Rodrigo, César
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First Integral and Variational Principle

2018
The third chapter covers the first integral and the variational principle. The notions of cyclic coordinates and Poisson brackets are first recalled. The Theorem of Poisson, Euler equation, and the variational principle are then addressed. An application in optics, namely the Fermat principle, is reviewed.
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A First-Order Variational Principle for Classical Electrodynamics

Physical Review, 1948
The fact that the Schr\"odinger and the Dirac equations for the wave function of an electron are differential equations of the first order with respect to time, while in classical theories differential equations of the second order are common, has necessitated a slightly different setup of the canonical theory in both fields.
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Crown component variation in hominoid upper first premolars

Archives of Oral Biology, 1978
Abstract Hominoid upper first premolar variation was assessed using seven crown component measures. Compared to the conventional measures of maximum dental length and breadth, the new measurements were a better source of taxonomic discrimination.
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First and Second Order Quadratic Variations. Wavelet-Type Variations

2013
In this chapter we study the asymptotic behavior of the quadratic variation (including standard quadratic, quadratic variation based on higher order increments or wavelet-type quadratic variations) for several self-similar processes, such as fractional Brownian motion, the Rosenblatt process, the Hermite process of general order or the solution to the ...
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