Analysis and development prospects of electronic and mobile payments in Russia

The article analyses electronic systems development, its impact on the development of the economy and a number of sectors of life. It enumerates and analyses basic forms of ecash circulation. The article demonstrates the need for development of this sphere of economy as well as financial systems

Process Monitoring of a Vibration Dampening CFRP Drill Tube in BTA deep hole drilling using Fibre-Bragg-Grating Sensors

The large tool length in BTA deep hole drilling often leads to strong torsional vibrations of the tool system, leading to a reduced bore hole quality failures. When substituting steel drill tubes with tubes from composite material, the laminate structure dampens these vibrations. Secondly, the integration of sensors allow to monitor process vibrations. This contribution introduces a new sensor platform to measure process vibrations, feed force and drilling torque using Fibre-Bragg Grating Sensors. The presented experimental results focus on characteristic frequency spectra with natural torsional and compression frequencies of the CFRP drill tube, which show variations due to changed feed

Characterisation and Modelling of Moisture Gradients in Polyamide 6

Polyamide 6 (PA6) is able to absorb water from the surrounding air and bond to it by forming hydrogen bonds between the carbonamide groups of its molecular chains. Diffusion processes cause locally different water concentrations in the (component) cross-section during the sorption process, resulting in locally different mechanical properties due to the water-induced plasticisation effect. However, the water content of PA6 is usually specified as an integral value, so no information about a local water distribution within a component is provided. This paper shows a method to characterise moisture distributions within PA6 samples using low-energy computer tomography (CT) techniques and comparing the reconstructed results with a developed finite elements (FE) modelling method based on Fick’s diffusion laws with concentration-dependent diffusion coefficients. For this purpose, the ageing of the samples at two different water bath temperatures as well as at different integral water contents are considered. The results obtained by CT reconstruction and FE modelling are in very good agreement, so that the concentration distributions by water sorption of PA6 calculated by FEM can be regarded as validated

Moisture Transport in PA6 and its Influence on the Mechanical Properties

Various studies have reported the changes in the mechanical properties and the modification in morphology of polyamide due to the absorption of water. However, the relation between the local water content and the alteration in the properties has not been consolidated in a coupled model yet. In the current work, a simulation model is proposed that can capture the diffusion of water as well as simulate the effect of the local moisture content on the stiffness of polyamide (PA6). To this end, a finite element model was developed by coupling of a nonlinear diffusion model and a viscoelastic material model. The Galerkin finite element method was used to formulate the weak form of the equations for the two physical processes. The coupled nonlinear equations were solved with the help of the Newton method. The diffusion process was studied experimentally with the help of gravimetric measurements. Relaxation tests were conducted on the polyamide specimens that were saturated under different moisture levels. Based on these experimental results, the dependency of the material parameters on the local moisture content was identified and an efficient and stable numerical simulation model has been developed