In this paper the experimental results of piezoelectric and magnetostrictive ultrasonic stimulation are comparatively analyzed in the evaluation of impact damage in a graphite epoxy composite sample chosen for a round robin test. By comparing theoretical and experimental results, it is shown that the equivalent power of internal friction can reach some hundreds mill watt per a single crack.

This paper is content of brief review of the problems of uptake, translocation and distribution of zinc in grass (Agros1is capillarisi. Grasses as well as other plant species growing on metal contaminated soil have been selected for metal resistance for a long time. An increase in heavy metals like Zn, Pb and Cd in soil caused changes in root morphology and physiology as well as the tolerance of different plant species. The uptake and transport of zinc in plants is higher in older plants parts, like old or dead leaves, than in younger parts. There were measured the zinc resistance of the grass and bioaccurnularion in different parts of grasses.

Aby przeciwdziałać negatywnym skutkom rozwoju cywilizacji i chronić różnorodność gatunkową na Ziemi, potrzebna jest nam wiedza o organizacji ekosystemów.

A mode-locked Tm3+-doped fibre laser and amplifier operating at a central wavelength of 1994.3 nm is demonstrated. A thulium oscillator is passively mode-locked by a semiconductor saturable absorber mirror to generate an average power of 17 mW at a fundamental repetition rate of 81 MHz in a short linear cavity. This 2-µm laser train is amplified to an average power to 20.26 W by two double-clad thulium-doped allfibre amplifiers. The pulse energy, duration and peak power is 250 nJ, 23 ps and 9.57 kW, respectively. This represents one of the highest values of average power at ∼ 2-µm-wavelength for picosecond thulium-doped fibre lasers and amplifiers. The performance of the laser system is described in details.

The objective of this study was to investigate the influence of aluminium coagulants basicity on the minimalisation of undesirable effects of coagulation such as decreasing pH and alkalinity, thereby water corrosivity. The experiments involved three types of surface water samples: from the Odra and Oława Rivers and a mountain stream, which differed in physico-chemical composition (especially in pH values and alkalinity). Alum (ALS) and polyaluminium chlorides (PACI) characterized by various basicity (r, %) were used as coagulants. The experimental results showed that decrease in water corrosivity depended on the basicity and dose of coagulant, pH and temperature of water prior to coagulation. With the increment of coagulation basic i ty the chemical stability of treated water improved and coagulants PAX-XL 3 and PAX-XL6 l were the best. Using of polyaluminium chlorides instead of alum decreased not only undesirable effects of coagulation but improved also the efficiency of water treatment.