The influence silicon dioxide nanoparticles on mechanical properties of erythrocyte and platelet membranes estimated by atomic force microscopy method

The investigation performed within the Programs of State Research “Energy systems, process and technologies”, project 2.2

Predicting the flow-induced dispersion and orientation of steel fibers in self-consolidating concrete by Distinct Element Method

The addition of fibres into a cementitious matrix with adapted rheology may lead to a randomly uniform dispersion and an orientation of the fibres tailored to the specific foreseen structural application. It has been in fact shown that thanks to a well balanced set of fresh state properties of the mixture, the fibres can be orientated in the direction of the concrete flow, leading to superior mechanical properties in the same direction. The performance of the structure can thus be optimized by designing the casting process so that the direction of flow, along which fibres may be aligned, matches as close as possible with the direction of principal tensile stresses within the structural element. It will be hence possible, thanks to the selection of suitable performance in the fresh state and to an optimized “design” of the casting flow, to govern the dispersion and orientation of the fibres and hence the resulting material and structural performance. To accomplish this task, reliable numerical tools able to properly describe the behaviour of advanced fibre reinforced cementitious materials in the fresh state are required in order to optimize the casting process, also with reference to the geometry of the element, and predict the orientation of the fibres. In this paper a Distinct Element Method has been employed to simulate the dispersion and flow-induced orientation of fibres in slump flow tests performed on fibre reinforced concretes characterized by different levels of fresh state performance. Results of numerical simulation have been compared with experiments, as a first step to calibrate the approach for further modelling of real casting case studies

GRODNO STATE MEDICAL UNIVERSITY CELEBRATES ITS 60TH ANNIVERSARY

Anniversaries are an important event in the activities of the university. For over 60 years of its history, Grodno State Medical University has become a major educational, scientific and clinical center in the education and health care system of the Republic of Belarus. The article provides information on the current state of the university, its main achievements, scientists and staff who have made significant contributions to the establishment and development of the university

Prediction of the Main Gear Lifetime of BELAZ Dump Truck at the Design Stage

The purpose of the research is to improve the method for calculating the lifetime of bevel gears with a circular tooth of the driving axle of the BELAZ dump truck with a hydromechanical transmission. An analysis of domestic and foreign calculation methods showed that when determining the contact stresses in the gearing, the influence of the modification of the side surfaces of the teeth on the magnitude of internal dynamic loads is not taken into account, which leads to a significant overestimation of the calculated lifetime of gears during their design. The solution to the problem is the introduction of refinement coefficients into the calculation methods traditionally used in OJSC “BELAZ”, the values of which are determined according to the recommendations of the Gleason company (USA), the supplier of gear-cutting equipment to OJSC “BELAZ”. Comparison of the actual value of the lifetime of the gear wheels of the main gear, established according to the results of the career operation of the BELAZ dump truck with a carrying capacity of 90 t with a hydromechanical transmission (about 142,000 km of run), with the results of calculating the lifetime using the proposed (134,000 km of run) and traditional (167,000 km of run) methods showed that the relative error in estimating the lifetime of the bevel gears of the drive axle of the dump truck, calculated by the proposed method, is about 6 %, and by the traditional one — 15.5%