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.

Properties of emulsions and free emulsion (Aqueous) films stabilized with hexylamine-modified silica

Abstract: The type and stability of emulsions, as well as the stability and thickness of free aqueous emulsion films stabilized with Aerosil-hexylamine mixtures, have been studied. The rheological characteristics (dynamic yield stress, elasticity modulae, and viscosity) have been measured for suspensions from which emulsions and films have been prepared. It has been shown that the properties of the films depend on the rheological properties of the suspensions.

Antitumor Activity of Selenium and Search Parameters for Its New Potentially Active Derivatives

Abstract: The trace element selenium is known to manifest antitumor activity. There is a relationship between the development of cancer and selenium content in food. Recent data demonstrated the necessity of increasing selenium consumption for the prevention and treatment of oncological diseases. Certain features of cancer cells and potential targets of selenium therapy are discussed. Both natural forms of selenium, namely, element Se, sodium selenite, L-selenocystine, L-selenomethionine, and L-methylselenocysteine, and synthetic ones, methylseleninic acid and imidoselenocarbamate derivatives, which display antitumor activity due to the generation of methylselenol and hydrogen selenide, the main anticarcinogenic metabolites, are reviewed. New promising anticancer selenium compounds, diacetophenonyl selenide, 2-methylselanyl-1-phenylethanol, and amino acids 2-amino-3-selanyl butanoic acid and 2-amino-3-(methylselanyl) butanoic acid are discussed.

Boundary element modelling of cohesive cracks using displacement discontinuity method

Abstract: In this paper a cohesive crack model is employed in a boundary element two-dimensional context in order to solve the nonlinear process of crack initiation and propagation. The direct boundary element method is used to model the finite domain of the body, while the displacement discontinuity elements are utilized to represent the cracks. The technique presented has the potential to analyse quasibrittle materials, such as concrete, rocks and others. Once the crack at a given point is initiated, a linear softening stress-opening displacement constitutive law is defined to simulate the softening of the material. The required fracture mechanics parameter, such as fracture energy, is also put into solution by means of the constitutive relationship. A nonlinear iteration scheme is developed in order to reach the required accuracy. It appears that the displacement discontinuity method is very well suited to model fracture of the quasibrittle materials, which have relative displacements across their surfaces. Fracture problems involving edge cracks, interior cracks and multiple cracks could be considered. The phenomenon of the crack closure can also be taken into account. A computer program is developed and some numerical results are provided to show the efficiency of the present formulation.

Hydrogenous mineral neoformations in Tomsk water intake facility from underground sources

Abstract: The article considers study outcomes of hydrogenous mineral neoformations precipitated on deferrization filters of Tomsk water intake facility from underground sources. Compositionally, these precipitations are colloform and polymineral including ferrous, carbonate and aluminosilicate mineral phases. Ferrous phase predominates and embraces ferric hydroxides (ferrihydrate, goethite, hematite and lepidocrocite) and ferrous hydrophosphates (vivianite, strengite, strunzite and rockbridgeit). Carbonate and aluminosilicate minerals are calcite and kaolinite-group, respectively.