JOINIG OF MG ALLOY AZ31B BY SELECTED TECHNOLOGIES

This contribution presents metallurgical joining of Mg alloy AZ 31B by several technologies - Friction Stir Welding - FSW, Laser Beam Welding - LBW, soldering and their mutual comparison. The difficulty of joining Mg alloys is connected with the strong MgO layer, low ductility of the weld metal (WM), a presence of intermetallic phases connected with the hardness increase. To successfully join Mg alloys, a precise setting of welding parameters is needed. The welds are susceptible to low mechanical properties as all samples fractured at WM. From the tested methods, laser beam welding proved the best results, because laser welding is the fastest and weld strength reached the highest values, i.e. 87% of BM (base metal) strength

Adaptable system increasing the transmission speed and reliability in packet network by optimizing delay

There is a great diversity in the transmission technologies in current data networks. Individual technologies are in most cases incompatible at physical and partially also at the link layer of the reference ISO/OSI model. Network compatibility, as the ability to transmit data, is realizable through the third layer, which is able to guarantee the operation of the different devices across their technological differences. The proposed inverse packet multiplexer addresses increase of the speed and reliability of packet transmission to the third layer, and at the same time it increases the stability of the data communication by the regulation of the delay value during the transmission. This article presents implementation of a communication system and its verification in real conditions. The conclusion compares the strengths and weaknesses of the proposed control system

Advanced Functions of a Modern Power Source for GMAW Welding of Steel

This paper evaluates the use of a modern welding power source equipped with advanced arc control functions. At the Laboratory of Welding Technologies of CTU in Prague we have focused on GMAW welding of steel using Sigma Galaxy, a modern welding power source produced by Migatronic. Sigma Galaxy is equipped with functions called Intelligent Arc Control and Sequence Repeat. According to the manufacturer, controlling an arc by these functions should significantly stabilize the welding process, lower the heat input and the deformation, and improve the weld quality. To evaluate the benefits of these functions completely, single V butt welds were performed on S275J2 structural steel 10 mm in thickness (2 weld layers: root+capping layer) in PF and PG positions. Welding was monitored by the Welding Information System, and was compared with standard GMAW welding. The results have shown that these “intelligent” functions offer significant advantages for steel welding, especially in vertical and overhead positions, because they lower the heat input and improve the weld metal control

WELDING OF NITINOL BY SELECTED TECHNOLOGIES

Nitinol is a perspective alloy that is difficult to weld because of its high sensitivity to heat, atmospheric gases and the NiTi phase instability. We evaluated several welding techniques with regard to their applicability to weld fine pseudoelastic NiTi wires. Namely, we tested the microplasma arc, laser, electron beam, resistance and capacitor discharge welding. In conclusion, the behaviour of the weld for any of the implemented welding techniques is similar; it leads to a loss of mechanical properties in the welded joint caused by a recrystallization and an increased amount of brittle intermetallic phases. Yet, under perfect shielding and with a minimum heat input, the welds could, as a whole, retain the majority of their properties, and, as such, have the desired properties close to the base metal

Software for reporting electricity production from photovoltaic panels

Cílem této práce je vytvoření softwaru pro evidenci, vykazování a fakturaci výroby elektrické energie z obnovitelných zdrojů. Po krátkém úvodu do legislativy výroby elektřiny z fotovoltaických panelů, jsou porovnány konkurenční produkty a nakonec je popsán vznik vlastního softwaru.The aim of this bachelors thesis is creating software for reporting electricity production from photovoltaic panels. After a short brief of legislation problems, there is comparasion of competitive products.Katedra informačních technologiíObhajoba bakalářské práce proběhla na požadované úrovni. Student reagoval na dotazy a připomínky vedoucího a komise. Cíle práce byly splněny a realizovaná aplikace je využitelná v praxi

Advanced Functions of a Modern Power Source for GMAW Welding of Steel

This paper evaluates the use of a modern welding power source equipped with advanced arc control functions. At the Laboratory of Welding Technologies of CTU in Prague we have focused on GMAW welding of steel using Sigma Galaxy, a modern welding power source produced by Migatronic. Sigma Galaxy is equipped with functions called Intelligent Arc Control and Sequence Repeat. According to the manufacturer, controlling an arc by these functions should significantly stabilize the welding process, lower the heat input and the deformation, and improve the weld quality. To evaluate the benefits of these functions completely, single V butt welds were performed on S275J2 structural steel 10 mm in thickness (2 weld layers: root+capping layer) in PF and PG positions. Welding was monitored by the Welding Information System, and was compared with standard GMAW welding. The results have shown that these “intelligent” functions offer significant advantages for steel welding, especially in vertical and overhead positions, because they lower the heat input and improve the weld metal control