What is the limit of improvement the structure obtained directly from the liquid state, with possible heat treatment (supersaturation and aging)? This question was posed by casting engineers who put arbitrary requirements on reducing the DAS (Dendrite Arm Spacing) length to less than a dozen microns. The results of tests related to modification of the surface microstructure of AlSi7Mg alloy casting treated by laser beam and the rapid remelting and solidification of the superficial casting zone, were presented in the paper. The local properties of the surface treated with a laser beam concerns only a thickness ranging from a fraction to a single mm. These local properties should be considered in the aspect of application on surfaces of non-machined castings. Then the excellent surface layer properties can be used. The tests were carried out on the surface of the casting, the surface layer obtained in contact with the metal mould, after the initial machining (several mm), was treated by the laser beam. It turned out that the refinement of the microstructure measured with the DAS value is not available in a different way, i.e. directly by casting. The experimental-simulation validation using the Calcosoft CAFE (Cellular Automaton Finite Element) code was applied.

Celem przeprowadzonych badań było określenie sum ważonych pierwiastków kwadratowych koncentracji względnych makro- i mikroelementów (według Czarnowskiego) w roślinach wodnych z gatunków Nymphaea alba L. i Nuphar lutea (L.) Sibith. & Sm., pochodzących z 14 jezior Pojezierza Leszczyńskiego. Wartości sum ważonych mieszczą się w zakresie od 13,2 do 13,8 dla Nymphaea alba L. oraz od 13,5 do 14,0 dla Nuphar lutea (L.) Sibith. & Sm. Z powodu w'ysokich zawartości wapnia i sodu w liściach badanych roślin, sumy ważone przekraczały wartość 12,5, podawaną przez Czarnowskiego. Istotna, ujemna korelacja między zawartościami względnymi potasu i wapnia świadczy o wzajemnym antagonizmie tych kationów. Z kolei dodatnie korelacje pomiędzy potasem i azotem, magnezem i cynkiem, kadmem i ołowiem, żelazem i miedzią, żelazem i glinem, glinem i manganem, kadmem i manganem, kadmem i niklem, kadmem i cynkiem oraz niklem i cynkiem potwierdzają możliwość wystąpienia oddziaływań synergistycznych.

A sensing system utilizing a standard optical fiber as a distributed sensor for the detection and localization of mechanical vibrations is presented. Vibrations can be caused by various external factors, like moving people, cars, trains, and other objects producing mechanical vibrations that are sensed by a fiber. In our laboratory we have designed a sensing system based on the Φ-OTDR (phase sensitive Optical Time Domain Reflectometry) using an extremely narrow laser and EDFAs.

The Author discusses the communist period of Polish history as it is pictured in selected products of contemporary popular culture. The present paper is based on textual analysis of comic books on the history of PRL (the first ones which appeared after 1989) and hip-hop songs.