Spectral Shape of Relaxations in Silica Glass

Precise low-frequency light scattering experiments on silica glass are presented, covering a broad temperature and frequency range (9 GHz < \nu < 2 THz). For the first time the spectral shape of relaxations is observed over more than one decade in frequency. The spectra show a power-law low-frequency wing of the relaxational part of the spectrum with an exponent $\alpha$ proportional to temperature in the range 30 K < T < 200 K. A comparison of our results with those from acoustic attenuation experiments performed at different frequencies shows that this power-law behaviour rather well describes relaxations in silica over 9 orders of magnitude in frequency. These findings can be explained by a model of thermally activated transitions in double well potentials.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

Investment in Gdańsk

Polskę na przestrzeni kilku ostatnich lat charakteryzuje wyjątkowo duża dynamika w zakresie realizacji inwestycji infrastrukturalnych. Stało się to możliwe dzięki przystąpieniu Polski do Unii Europejskiej i możliwości pozyskania środków finansowych z funduszy strukturalnych UE na realizację inwestycji. Tym samym stworzyliśmy sobie szansę na zmniejszenie dystansu cywilizacyjnego, który pod względem jakości życia i poziomu infrastruktury dzielił Polskę od standardów w miastach unijnych.Over recent times Poland has experienced extremely dynamic growth in infrastructure investment. This has become possible due to the country’s membership of the European Union and the possibility of obtaining support for investment projects from the EU’s structural funds. An opportunity has thus been created to reduce the differences, in terms of quality of life and standard of infrastructure, that has existed between Poland and towns in other EU countries

Influence of temperature gradient on surface texture measurements with the use of profilometry

The paper presents an analysis of influence of ambient temperature changes on the values of parameters in topography measurements with the use of different profilometry techniques. In order to check this, a series of measurements was performed. Two multiprofilometry instruments were used - a contact profilometer, further equipped with an interferometric transducer, and an optical one with a confocal probe. Measurements were performed on first-class flat interferometric glass and on an A-type roughness standard - under different conditions, with simultaneous registration of differences in ambient temperature values. These values were either intentionally changed or the temperature variations were the result of air conditioning control. The performed research showed that - despite the asperities on the surface being really small - there is a relationship between changes of temperature and the results obtained from the measured surface, which in some cases can be seriously distorted

Encapsulation of fluorescein into nanozeolites L and Y

International audienc

Analysis and evaluation of progress in the implementation of a road tunnel under the Martwa Wisła River in Gdańsk, Poland

Budowa tunelu drogowego pod Martwą Wisłą jest częścią przedsięwzięcia inwestycyjnego „Połączenie Portu Lotniczego z Portem Morskim Gdańsk–Trasa Słowackiego”. Tunel drogowy pod Martwą Wisłą w Gdańsku wraz z węzłem Marynarki Polskiej jest obiektem inżynierskim o całkowitej długości 2.155 metrów. Połączy on wschodnie tereny portowe z zachodnimi w rejonie nabrzeży „Dworzec Drzewny” oraz „Nabrzeże Wiślane”. Długość sekcji tunelowej to 1.377,5 metra, w tym tunel drążony metodą TBM o długości 1.072,5 metra i średnicy 12,5 metra. W artykule zaprezentowana została analiza ekonomiczna projektu, jak również analiza techniczna, która doprowadziła do wyboru metody wykonania tunelu w technologii TBM. Szeroko zostały również omówione warunki gruntowo-wodne w rejonie inwestycji oraz metody ich badania. Artykuł opisuje instalację maszyny TBM, zakładu separacji urobku z płuczki wiertniczej, drążenie tunelu, wymianę narzędzi tnących tarczy w czasie drążenia tunelu, produkcję tubingów oraz budowę przejść poprzecznych między rurami tunelu. Artykuł podsumowuje również osiągnięte efekty w czasie drążenia tunelu pod Martwą Wisłą.Road tunnel under the Martwa Wisła river is the part of the Słowacki Route, providing convenient connection between the Gdansk Lech Walesa Airport and the Port of Gdansk. The tunnel together with the Marynarki Polskiej junction is an engineering object with the total length of 2,155 meters. Length of the tunnel section is 1,377.5 meters including the TBM tunnel length of 1,072.5 meters. The dimension of the two tunnel tubes is 12.5 meters each. The study “Analysis and evaluation of progress in the implementation of the road tunnel under the Martwa Wisła river in Gdańsk, Poland” proves the importance of the tunnel for the improvement of traffic condition in Gdańsk and in the development of the city. This article presents an economic analysis of the project as well as technical analysis concerning the choice of TBM method of the crossing the river. It also widely presents the geological and hydrogeological conditions, the methodology of surveys on these conditions. The article describes installation of the TBM, separation plant to clear slurry, principle of operations, boring advance of TBM, assessment of the cutter head and replacement of the damaged tools. Also fabrication of the tubing precast elements in the study as well as the process of building the cross-passages between the tubes of the tunnel are presented in the article. Finally the study provides the summary of the effects achieved during tunnelling under the Martwa Wisła river

Influence of temperature gradient on surface texture measurements with the use of profilometry

The paper presents an analysis of influence of ambient temperature changes on the values of parameters in topography measurements with the use of different profilometry techniques. In order to check this, a series of measurements was performed. Two multiprofilometry instruments were used - a contact profilometer, further equipped with an interferometric transducer, and an optical one with a confocal probe. Measurements were performed on first-class flat interferometric glass and on an A-type roughness standard - under different conditions, with simultaneous registration of differences in ambient temperature values. These values were either intentionally changed or the temperature variations were the result of air conditioning control. The performed research showed that - despite the asperities on the surface being really small - there is a relationship between changes of temperature and the results obtained from the measured surface, which in some cases can be seriously distorted

Synthesis of fluorescein by a ship-in-a-bottle method in different zeolites

International audienc

Towards the superlubricity of polymer–steel interfaces with ionic liquids and carbon nanotubes

Frictional losses are responsible for significant energy waste in many practical applications, and superlubricity with a coefficient of friction lower than 0.01 is the goal of tribologists. In this paper, metal-on-polymer contact was analysed and close to superlubricity conditions for this material configuration were explored. A new lubricant has been proposed hinge on the phosphorus-based ionic liquid and carbon nanotubes as thickeners. Additionally, carbon nanotube mesh was doped with copper nanoparticles that allowed for the close to superlubricity state in a mild steel/polymer contact configuration under low normal load conditions. The adsorption of phosphorus onto metallic and polymer surfaces has been reported in EDS analysis. The formulation of the new lubricant allowed for stable dispersion with a carbon nanotube content as low as 0.1% wt. The carbon nanotubes and Cu nanoparticles have been analysed using TEM and SEM imaging. A tribological test in a block-on-ring system has been carried out. The wear of material, topography, and surface free energy have been analysed along with SEM/EDS images to explore the underlying mechanisms of friction and wear