Search results for "CONSTANT"
showing 10 items of 1718 documents
Les traductions latines de textes hagiographiques byzantins de la période médio-byzantine
2019
The present article attempts to record and present as much as possible the Latin translations of hagiographical texts during the Middle Byzantine period. The texts are first approached from a literary point of view, then a historical presentation is attempted, referring to their possible functional use in the traditions of the two churches, Constantinople and Rome.
Estudios previos y propuesta de intervención en las pinturas murales, esculturas y ornamentos de la Real Parroquia de los Santos Juanes de Valencia
2020
Throughout this article, the most representative aspects of the previous studies and the intervention proposal, carried out for the restoration of the paintings, sculptures and ornaments of the Royal Parish of the Santos Juanes in Valencia, are exposed. A project of this magnitude involves the effort and dedication of a great team, resulting in one-year work with exhaustive and constant research with the purpose of safeguarding the heritage assets of the church. With this article we want to make known the importance that these previous studies acquire. Been essential since they are the starting point and the basis for the execution of the restoration works that will be carried out during fo…
On Holditch's theorem and related kinematics
2019
El teorema de Holditch es un resultado clásico sobre áreas de curvas planas generadas por el movimiento de segmentos. Esta construcción está estrechamente relacionada con otros tipos de curvas como, por ejemplo, curvas paralelas, curvas de anchura constante o curvas de bicicletas. Se compilan las propiedades básicas de este tipo de curvas y se da una revisión histórica sobre el teorema de Holditch y teoremas relacionados de cinemática. Primero, la situación plana de Holditch se define rigurosamente y se consideran ciertos problemas como la existencia de dicha construcción o el modo de evitar movimientos retrógrados en el segmento que se va moviendo. En el enunciado del teorema de Holditch a…
Giustizia ambientale e recupero delle aree verdi: il caso di Palermo
2021
L’urban shrinkage è diventata una questione centrale tanto nel dibattito scientifico quanto nell’agenda politica di diverse città europee. Secondo i dati EUROSTAT (2019), circa il 40% delle città europee con più di 200.000 abitanti stanno perdendo popolazione; una contrazione che si esplicita maggiormente, sotto il profilo spaziale, in una progressiva sottoutilizzazione del patrimonio edificato, così come nel contestuale incremento di aree e terreni in stato di abbandono. In questo quadro controverso di mutazione strutturale della città, così come l’abbiamo conosciuta, le politiche urbane alla prova in Europa tentano di declinare la decrescita quale occasione strategica di investimento sull…
BIBO Stability Analysis for Delay Switched Systems with Nonlinear Perturbation
2013
Published version of a paper from the journal:Abstract and Applied Analysis. Also available from Hindawi:http://dx.doi.org/10.1155/2013/738653 The problem of bounded-input bounded-output ( BIBO) stability is investigated for a class of delay switched systems with mixed time-varying discrete and constant neutral delays and nonlinear perturbation. Based on the Lyapunov-Krasovskii functional theory, new BIBO stabilization criteria are established in terms of delay-dependent linear matrix inequalities. The numerical simulation is carried out to demonstrate the effectiveness of the results obtained in the paper.
Absolute acidity of clay edge sites from ab-initio simulations
2012
International audience; We provide a microscopic understanding of the solvation structure and reactivity of the edges of neutral clays. In particular we address the tendency to deprotonation of the different reactive groups on the (0 1 0) face of pyrophyllite. Such information cannot be inferred directly from titration experiments, which do not discriminate between different sites and whose interpretation resorts to macroscopic models. The determination of the corresponding pKa then usually relies on bond valence models, sometimes improved by incorporating some structural information from ab-initio simulations. Here we use density functional theory based molecular dynamics simulations, comb…
Structure and Properties of YbZnSn, YbAgSn, and Yb2Pt2Pb
1999
Abstract YbZnSn, YbAgSn, and Yb2Pt2Pb were synthesized by reacting the elements in sealed tantalum tubes in a high-frequency furnace. The structures of YbAgSn and Yb2Pt2Pb were refined from single crystal X-ray data: YbAgPb type, P 6 m2, a=479.2(2) pm, c=1087.3(3) pm, wR2=0.050, BASF=0.34(8), 509 F2 values, 18 variables for YbAgSn and Er2Au2Sn type, a=776.0(1) pm, c=701.8(2) pm, wR2=0.072, 426 F2 values, 18 variables for Yb2Pt2Pb. The lattice constants of YbZnSn are confirmed: NdPtSb type, P63mc, a=464.7(1) pm, c=747.7(2) pm. The stannides YbZnSn and YbAgSn crystallize with superstructures of the AlB2 type. The zinc (silver) and tin atoms form ordered Zn3Sn3 and Ag3Sn3 hexagons, respectivel…
A Cost-Effective 3D Acquisition and Visualization Framework for Cultural Heritage
2020
Museums and cultural institutions, in general, are in a constant challenge of adding more value to their collections. The attractiveness of assets is practically tightly related to their value obeying the offer and demand law. New digital visualization technologies are found to give more excitements, especially to the younger generation as it is proven by multiple studies. Nowadays, museums around the world are currently trying to promote their collections through new multimedia and digital technologies such as 3D modeling, virtual reality (VR), augmented reality (AR), and serious games. However, the difficulty and the resources required to implement such technologies present a real challen…
Study of the column efficiency using gradient elution based on Van Deemter plots.
2018
Performance of chromatographic columns is of major importance in the development of more efficient separation methods. So far, a common practice is to study the column behavior in isocratic elution by modifying the flow rate and fitting the theoretical plate height values versus the mobile phase linear velocity, according to the Van Deemter equation. In this work, an approach is presented to extend the measurement of efficiency to linear gradient elution, where the mean retention factor is kept constant at each assayed flow. This avoids a possible source of uncertainty due to the change in the distribution equilibria profile, and makes the mean interactions with the stationary phase in grad…
Natural optical anisotropy of h-BN: Highest giant birefringence in a bulk crystal through the mid-infrared to ultraviolet range
2018
The giant birefringence of layered h-BN was demonstrated by analyzing the interference patterns in reflectance and transmittance measurements in the mid-infrared to the deep ultraviolet energy range. The refractive index for polarization perpendicular to the c axis is much higher than the refractive index for polarization parallel to the c axis, and it displays a strong increase in the ultraviolet range that is attributed to the huge excitonic effects arising from the unique electronic structure of h-BN. Thus, h-BN is shown to exhibit a giant negative birefringence that ranges from -0.7 in the visible to -2 in the deep ultraviolet close to the band gap. The electronic dielectric constants f…