University of Architecture, Civil Engineering and Geodesy

About: University of Architecture, Civil Engineering and Geodesy is a education organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Finite element method & Beam (structure). The organization has 3808 authors who have published 3822 publications receiving 30736 citations. The organization is also known as: Sofia Polytechnic.

Analysis of F-contractions in function weighted metric spaces with an application

Abstract: Abstract In this work, we show that the existence of fixed points of F-contraction mappings in function weighted metric spaces can be ensured without third condition ( F 3 ) (F3) imposed on Wardowski function F :(0, ∞ ) → ℜ F\\mathrm{:(0,\\hspace{0.33em}}\\infty )\\to \\Re . The present article investigates (common) fixed points of rational type F-contractions for single-valued mappings. The article employs Jleli and Samet’s perspective of a new generalization of a metric space, known as a function weighted metric space. The article imposes the contractive condition locally on the closed ball, as well as, globally on the whole space. The study provides two examples in support of the results. The presented theorems reveal some important corollaries. Moreover, the findings further show the usefulness of fixed point theorems in dynamic programming, which is widely used in optimization and computer programming. Thus, the present study extends and generalizes related previous results in the literature in an empirical perspective.

Study of near white light emission for ZnO thin films grown on silicon substrates

Abstract: ZnO thin films at growth time of 6, 8, 10 and 12 h were prepared by hydrothermal approach. The microstructure, surface morphology and photoluminescence properties were investigated by x-ray diffraction, field-emission scanning electron microscope and fluorescence spectrometer. The results reveal that all the thin films have hexagonal wurzite structure and preferential orientation along the c-axis. The density of nanorods increases first and then decreases with the increase of growth time. The photoluminescence spectra consist of sharp near band-edge, broad visible and near-infrared emissions. The chromaticity coordinates and color rendering indices of ZnO thin film at growth time of 10 h are x = 0.3537, y = 0.3744 and 90, respectively. The mechanisms of the green, yellow, orange-red, red and near-infrared emissions were discussed in detail.

Nonlinear analysis of cable-supported structures with a spatial catenary cable element

Abstract: This paper presents a spatial catenary cable element for the nonlinear analysis of cablesupported structures. An incremental-iterative solution based on the Newton-Raphson method is adopted for solving the equilibrium equation. As a result, the element stiffness matrix and nodal forces are determined, wherein the effect of self-weight and pretension are taken into account. In the case of the initial cable tension is given, an algorithm for form-finding of cable-supported structures is proposed to determine precisely the unstressed length of the cables. Several classical numerical examples are solved and compared with the other available numerical methods or experiment tests showing the accuracy and efficiency of the present elements.