Metallographic and corrosion research of copper from archaeological sites

In this study, copper slabs - ingots, from both Gdańsk and Krakow were examined. Besides metallographic examinations, attention was focused on analyses of corrosion products. The following techniques were applied: scanning electron microscopy with fluorescent X-ray microanalysis and X-ray diffraction. The conducted investigations enabled determination of the causes of corrosion in the old copper slabs, due mainly to the mediaeval alloying techniques and copper processing technologies

Design of C-TYPE passive filter for arc furnaces

The article presents an example of power supply system modernization in one of Polish steelworks. For the existing power system containing 3rd harmonics filters it was necessary to design a C-type filter for the 2nd harmonics. Two design methods have been presented. The first method is based on the assumption concerning the desired harmonic current flow of filter adjustment between the filter and power grid. The second method was based on using a genetic algorithm, searching for the RT resistance value of the filter. Applying the genetic algorithm makes it possible to take into account the broad spectrum of the electrical environment where the filter will be working

Anonymous Communication on the Internet and Trolling

Internet Trolls are an online subculture who participate in posting upsetting or shocking content, harassing users, and spreading false information for their own enjoyment. As of the time of this study, research is limited on the trolling culture, the perception of trolls, and trolling behavior. The researchers have investigated trolling culture, as well as conducted a study in which subjects were asked to relay their emotional reactions to a selection of online comments, and mark the comments they considered to be trolling behavior. The results were meant to discover whether subjects of different age generations differed in their perception and definition of trolls. The results clarified that trolling was frequently associated with poor behavior, although the degree of disapproval and definitions for trolling varied between age groups

The Analysis of Foundry Engineering of Copper Alloys Based on the Research of a Metallurgist Settlement in Szczepidło

The article presents chosen aspects of foundry engineering of the settlement dwellers, including the archaeometric characteristics and metal science analysis of the artefacts, as well as an attempted reconstruction of the production organization. Discovered in Szczepidło (Greater Poland), the foundry workshop is unique in Central European Bronze Age. This workshop foundry operated roughly XIV-XII Century BC. Its production is evidenced by the presence of markers of the whole production cycle: semi-finished and finished products, production waste, fragments of crucibles and casting ladles with traces of usage, and tools. On this basis the alloys and foundry technologies used have been described. The analysis of foundry technology of copper alloys in the settlement area was carried out by observing the surface and structure of the products, semi-finished artefacts and fragments of crucibles by applying optical microscopy (OM), confocal microscopy (CLSM) and Xray radiography (RT). The investigations of compositions were made by means of the energy dispersive X-ray fluorescence spectroscopy (ED-XRF) and scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDS)

Refining processes in the copper casting technology

The paper presents the analysis of technology of copper and alloyed copper destined for power engineering casts. The casts quality was assessed based on microstructure, chemical content analysis and strength properties tests. Characteristic deoxidising (Logas, Cup) and modifying (ODM2, Kupmod2) formulas were used for the copper where high electrical conductivity was required. Chosen examples of alloyed copper with varied Cr and Zr content were studied, and the optimal heat treatment parameters were tested for a chosen chromium copper content, based on the criterion of hardness and electrical conductivity tests. Searching for materials with high wear resistance, the influence of variable silicone content on the properties of CuNiSi alloy was researched