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.

A new approach to predict the compression index using artificial intelligence methods

Abstract: The compression index is one of the important geotechnical parameters, essential for the structural design. Since the determination of the compression index based on oedometer tests is relatively expensive and time-consuming, different authors have proposed for its estimation models using regression analysis and artificial neuron networks. However, they have ignored several parameters that could have increased the predictive capability of models. Other studies have concluded that genetic programming could have yielded better results. Unfortunately, no compression index models or effective comparisons of different methods have been published. The aim of this study is to propose a novel approach for estimating the compression index more accurately. To test the approach, a comparison study using K-fold cross-validation technique was conducted utilizing several models of multilayer neural networks, genetic programming, and multiple regression analysis. These models have been applied to 373 oedometer t...

Diffractive–refractive correction units for plastic compact zoom lenses

Abstract: A method of designing a plastic zoom lens with a diffractive-refractive hybrid corrector, comprising one diffractive lens and one refractive lens, is described. The efficiency of this method is demonstrated by designing a compact zoom lens for a mobile phone. This zoom design, incorporating lenses made only of two commercial optical plastics (polymethylmethacrylate and polycarbonate), provides high optical performance.

Synthesis and properties of four coordination polymers built from a semi-rigid tripod carboxylic acid

Abstract: By using a semi-rigid multidentate carboxylate linker 4,4′,4′′-(((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene))tris(oxy))tribenzoic acid (H3L), four coordination polymers, namely, [Cd3(L)2(H2O)4]·(guest) (1), [Mn3(L)2(DMF)2(H2O)2]·(guest) (2), [Co7(L)4(DMF)6(COOH)2]·(guest) (3), and [Zn3(L)2(DMF)2(H2O)3]·(guest) (4), were obtained and characterized by single-crystal X-ray diffraction, thermogravimetric and photoluminescent studies. Compound 1 is a two-dimensional (2-D) hcb-type layered structure made of rare, interlocked double-layered honeycomb sheets. Compound 2 is a doubly-interpenetrating (3,6)-connected 3-D network, in which L and Mn3 act as triangle and trigonal prismatic nodes, respectively. Compound 3 has a (4,12)-connecting 3-D polycatenated network made of a rare four-ladder 2-D sheet, in which the Co7 cluster is considered as a 12-connecting node and the ligand L3− is a 3-connecting node. Similar to 1, compound 4 also possesses a 2-D hcb-type layered structure, but it is built from two interpenetrating single sheets. Compounds 1 and 4 exhibited strong blue photoluminescent emissions at room temperature upon excitation, owing to a ligand-centered excited state. The emission intensities of the two compounds varied upon contact with different solvents or analytes, exhibiting selective emission quenching responses towards nitroaromatics.