Wrocław University of Technology

About: Wrocław University of Technology is a education organization based out in Wrocław, Poland. It is known for research contribution in the topics: Laser & Fuzzy logic. The organization has 13115 authors who have published 31279 publications receiving 338694 citations.

Multi-element analysis, bioavailability and fractionation of herbal tea products

Abstract: Herbal teas (Mentha piperitae folium and mixture Marticaria chamomilla flos with Lavandula officinalis flos) were compared considering the total contents of micro (Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Ti, V) and macro (C, H, N, S, Ca, Mg, P) elements, bioavailability and fractionation. Different methods (inductively coupled plasma optical emission spectrometry (ICP OES), Fourier transform infrared spectroscopy (FTIR) and CHNS elemental analysis) were applied. The microwave-assisted digestion procedure was found to be more effective than the hot-plate heating for the wet acid digestion of tea. The application of the modified BCR (Community Bureau of Reference) sequential extraction procedure exhibited differences in the concentrations of metal bound to reducible and oxidizable fractions. The accuracy of method was verified by analysis of certified reference material INCT-TL-1 Tea Leaves. The daily intake of all elements from the analyzed herbal tea infusion did not exceed the maximum permissible levels and does not constitute health risk.

Ferroelectric domain engineering by focused infrared femtosecond pulses

Abstract: We demonstrate infrared femtosecond laser-induced inversion of ferroelectric domains. This process can be realised solely by using tightly focused laser pulses without application of any electric field prior to, in conjunction with, or subsequent to the laser irradiation. As most ferroelectric crystals like LiNbO3, LiTaO3, and KTiOPO4 are transparent in the infrared, this optical poling method allows one to form ferroelectric domain patterns much deeper inside a ferroelectric crystal than by using ultraviolet light and hence can be used to fabricate practical devices. We also propose in situ diagnostics of the ferroelectric domain inversion process by monitoring the Cerenkov second harmonic signal, which is sensitive to the appearance of ferroelectric domain walls.

Non-destructive strength characterization of concrete using surface waves

Abstract: The paper presents a description of non-destructive strength characterization of concrete, using ultrasonic probes, and of measuring surface wave velocity. Probes work at frequencies of 40 and 100 kHz, and they are equipped with an exponential waveguide, the end of which has a surface of ca. 1 mm2. A short characteristic of this type of probe is shown with an analysis of the influence of the inclination angle between the vertical and the examined surface as well as the influence of surface irregularities on ultrasonic wave propagation. The results of laboratory examination are described and examples of application of this measurement method in practice are given. It has been proved that this method has a number of advantages that are very useful in engineering practice.