New Approach for Modelling of the Welding Processes
The applying of new technologies is connected with considerable outlays to receive the optimal welding regimes, metallographic research of welding seams, joint quality control and other facilities, which can be considerable lowered, using modelling of the welding processes. We propose to use new approach for modelling – analogue modelling, which is based on process investigation, using logical functions. Some practical applying examples of the analogue modelling are offered in this paper. The analogue model of the heat input during resistance welding of wires with coating is described in detail. Using analogue modelling we can solve direct problems of thermal conductivity, it mean that we can predict temperature field, obtained as a result of influence of welding source of heat. The effectiveness of analogue modelling using is proven.
RESEARCH ON THE SURFACE COATINGS INFLUENCE ON FORMATION MECHANISM OF THE RESISTANCE WELDS
The goal of the work is the research of formation mechanism of the spot resistance welds in the case of copper wires with nickel and tin coatings. The existing approaches for investigation of the formation mechanisms of welds of wires with and without coatings are analysed. A new approach for modeling of welding joint formation is offered. The analog model of the heat input during resistance welding of
The peculiar thermo-structural behavior of the anionic lipid DMPG.
Aqueous dispersions of the anionic phospholipid dimyristoyl phosphatidylglycerol (DMPG), around 100 mM ionic strength, are known to exhibit a thermal behavior similar to that of the largely studied lipid dimyristoyl phosphatidylcholine (DMPC), which undergoes a gel to liquid crystalline phase transition at 23 degrees C, well characterized by differential scanning calorimetry (DSC), and other methods. However, at low ionic strength, DMPG has been shown to present a large gel-fluid transition region, ranging from 18 to 35 degrees C. This intermediate phase is optically transparent and characterized by a continuous change in membrane packing. Structural properties of the DMPG gel-fluid transition region will be discussed, based on results obtained by several techniques: electron spin resonance (ESR) of spin labels at the membrane surface and intercalated at different depths in the bilayer; light scattering; DSC; small angle X-ray scattering (SAXS); and fluorescence spectroscopy of probes in the bilayer.