Search results for "Quadrat"
showing 10 items of 344 documents
A FE-Meshless Multiscale Approach for Masonry Materials
2015
Abstract A FE-Meshless multiscale computational strategy for the analysis of running bond masonry is presented. The Meshless Method (MM) is adopted to solve the boundary value problem (BVP) at the mesoscopic level. The representative unit cell is composed by the aggregate and the surrounding joints, the former assumed to behave elastically while the latter are simulated as non-associated elastic-plastic zero-thickness interfaces with a softening response. Macroscopic localization of plastic bands is obtained performing a spectral analysis of the tangent stiffness matrix. Localized plastic bands are embedded into the quadrature points area of the macroscopic finite elements.
H and P Mesh Refinement in the Metal-Forming F.E.M. Analysis
1988
In this paper a comparison between H and P refinement techniques in the metal-forming F.E.M. analysis is carried out in order to evaluate their computational efficiency. The results are compared using a particular error estimator which locally allows determining the workpiece zones where the refinement is necessary.
3D-Chiral quadratic indices of the ‘molecular pseudograph’s atom adjacency matrix’ and their application to central chirality codification: classific…
2004
Quadratic indices of the 'molecular pseudograph's atom adjacency matrix' have been generalized to codify chemical structure information for chiral drugs. These 3D-chiral quadratic indices make use of a trigonometric 3D-chirality correction factor. These indices are nonsymmetric and reduced to classical (2D) descriptors when symmetry is not codified. By this reason, it is expected that they will be useful to predict symmetry-dependent properties. 3D-Chirality quadratic indices are real numbers and thus, can be easily calculated in TOMOCOMD-CARDD software. These descriptors circumvent the inability of conventional 2D quadratic indices (Molecules 2003, 8, 687-726. http://www.mdpi.org) and othe…
Non-stochastic quadratic fingerprints and LDA-based QSAR models in hit and lead generation through virtual screening: theoretical and experimental as…
2005
In order to explore the ability of non-stochastic quadratic indices to encode chemical information in antimalarials, four quantitative models for the discrimination of compounds having this property were generated and statistically compared. Accuracies of 90.2% and 83.3% for the training and test sets, respectively, were observed for the best of all the models, which included non-stochastic quadratic fingerprints weighted with Pauling electronegativities. With a comparative purpose and as a second validation experiment, an exercise of virtual screening of 65 already-reported antimalarials was carried out. Finally, 17 new compounds were classified as either active/inactive ones and experimen…
Hilbert modularity of some double octic Calabi--Yau threefolds
2018
We exhibit three double octic Calabi--Yau threefolds over the certain quadratic fields and prove their modularity. The non-rigid threefold has two conjugate Hilbert modular forms of weight [4,2] and [2,4] attached while the two rigid threefolds correspond to a Hilbert modular form of weight [4,4] and to the twist of the restriction of a classical modular form of weight 4.
Redundant Picard–Fuchs System for Abelian Integrals
2001
We derive an explicit system of Picard-Fuchs differential equations satisfied by Abelian integrals of monomial forms and majorize its coefficients. A peculiar feature of this construction is that the system admitting such explicit majorants, appears only in dimension approximately two times greater than the standard Picard-Fuchs system. The result is used to obtain a partial solution to the tangential Hilbert 16th problem. We establish upper bounds for the number of zeros of arbitrary Abelian integrals on a positive distance from the critical locus. Under the additional assumption that the critical values of the Hamiltonian are distant from each other (after a proper normalization), we were…
Spatial beam cleaning in quadratic nonlinear medium
2018
We show experimentally that a laser beam scrambled by propagation in a short segment of multimode fiber may be cleaned by the nonlinear propagation in KTP cristal with type-II second-harmonic generation.
Multipactor RF Breakdown in Coaxial Transmission Lines With Digitally Modulated Signals
2016
The aim of this paper is the study of the RF multipactor breakdown in coaxial transmission lines excited by a single carrier with a digitally modulated signal. Employing an in-house developed code, numerical simulations are performed to determine the RF multipactor voltage threshold for several digitally modulated signals under different modulations schemes: quadrature phase-shift keying, 16-quadrature amplitude modulation, 16-amplitude and phase-shift keying, and 32-amplitude and phase-shift keying. Moreover, a coarse method based on the envelope integration to determine the RF multipactor voltage threshold when involving arbitrary digital modulations is also presented. These results are a…
On the geometric structure of the class of planar quadratic differential systems
2002
In this work we are interested in the global theory of planar quadratic differential systems and more precisely in the geometry of this whole class. We want to clarify some results and methods such as the isocline method or the role of rotation parameters. To this end, we recall how to associate a pencil of isoclines to each quadratic differential equation. We discuss the parameterization of the space of regular pencils of isoclines by the space of its multiple base points and the equivariant action of the affine group on the fibration of the space of regular quadratic differential equations over the space of regular pencils of isoclines. This fibration is principal, with a projective group…
Existence and uniqueness of solutions to a quasilinear parabolic equation with quadratic gradients in financial markets
2005
A quasilinear parabolic equation with quadratic gradient terms is analyzed. The equation models an optimal portfolio in so-called incomplete financial markets consisting of risky assets and non-tradable state variables. Its solution allows to compute an optimal portfolio strategy. The quadratic gradient terms are essentially connected to the assumption that the so-called relative risk aversion function is not logarithmic. The existence of weak global-in-time solutions in any dimension is shown under natural hypotheses. The proof is based on the monotonicity method of Frehse. Furthermore, the uniqueness of solutions is shown under a smallness condition on the derivatives of the covariance (?…