Curious Variables Experiment (CURVE). CCD Photometry of QW Serpentis in Superoutburst and Quiescence

We report extensive photometry of the dwarf nova QW Ser throughout its 2003 February superoutburst till quiescence. During the superoutburst the star displayed clear superhumps with a mean period of Psh = 0.07703(4) days. In the quiescence we observed a double humped wave characterized by a period of P=0.07457(2) days. As both periods obey the Stolz-Schoembs relation with a period excess equal to 3.30+/-0.06% the latter period is interpreted as the orbital period of the binary system.Comment: accepted for publication in A&A, 5 pages, 7 figure

Enhancing the Fresh and Early Age Performances of Portland Cement Pastes via Sol-Gel Silica Coating of Metal Oxides (Bi2O3 and Gd2O3)

Data Availability Statement: The datasets generated and/or analyzed during this study are available from the corresponding author upon reasonable request.Copyright © 2023 by the authors. Incorporating metal oxide nanoparticles into cement-based composites delays the hydration process and strength gain of cementitious composites. This study presents an approach toward improving the performance of bismuth oxide (Bi2O3) and gadolinium oxide (Gd2O3) particles in cementitious systems by synthesizing core–shell structures via a sol-gel process. Two types of silica coatings on cementitious pastes with 5% and 10% substitution levels were proposed. The rheology, hydration, and mechanical properties of the pastes were analyzed to determine the relationship between the coating type and nanoparticle concentration. The results indicate that despite the significant disparities in the performance of the resulting material, both methods are appropriate for cement technology applications. Bi2O3’s silica coatings accelerate the hydration process, leading to early strength development in the cement paste. However, due to the coarse particle size of Gd2O3, silica coatings exhibited negligible effects on the early age characteristics of cement pastes.National Science Centre, Poland (project no. 2020/39/D/ST8/00975 (SONATA-16))

Curious Variables Experiment (CURVE). Variable properties of the dwarf nova SS UMi

We report on extensive photometry of the dwarf nova SS Ursae Minoris throughout nine months of 2004. In total, we recorded two superoutbursts and 11 normal outbursts of the star. SS UMi has been known to show frequent superoutbursts with a mean interval of 84.7 days. Our data suggest that the interval between successive superoutbursts lengthened to 197 days, indicating that SS UMi entered a period of untypical behavior manifested by a growth in the quiescent magnitude of the star and a series of frequent, low-amplitude, normal outbursts observed from July to September 2004. The mean superhump period derived for the April 2004 superoutburst of SS UMi is 0.070149(16) days (101.015 min). Combining this value with an earlier orbital period determination, we were able to derive the period excess, which is equal to 3.5 +/- 1.6%, and estimate the mass ratio of the binary system as equal to q=0.16 +/- 0.07. During the entire superoutburst, the period decreased at a rate of $\dot P/P_{\rm sh} = -6.3(1.4) \times 10^{-5}$. However, detailed analysis of the timings of superhump maxima seem to suggest a more complex period change, with a decrease in the period during the first and last stages of the superoutburst but an increase in the middle interval.Comment: 9 pages, 8 figures, in print in Astronomy & Astrophysic

Functional Bi2O3/Gd2O3 Silica-Coated Structures for Improvement of Early Age and Radiation Shielding Performance of Cement Pastes

Data Availability Statement: The datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request.Copyright © 2024 by the authors. This study presents a new approach towards the production of sol-gel silica-coated Bi2O3/Gd2O3 cement additives towards the improvement of early mechanical performance and radiation attenuation. Two types of silica coatings, which varied in synthesis method and morphology, were used to coat Bi2O3/Gd2O3 structures and evaluated as a cement filler in Portland cement pastes. Isothermal calorimetry studies and early strength evaluations confirmed that both proposed coating types can overcome retarded cement hydration process, attributed to Bi2O3 presence, resulting in improved one day compressive strength by 300% and 251% (depending on coating method) when compared to paste containing pristine Bi2O3 and Gd2O3 particles. Moreover, depending on the type of chosen coating type, various rheological performances of cement pastes can be achieved. Thanks to the proposed combination of materials, both gamma-rays and slow neutron attenuation in cement pastes can be simultaneously improved. The introduction of silica coating resulted in an increment of the gamma-ray and neutron shielding thanks to the increased probability of radiation interaction. Along with the positive early age effects of the synthesized structures, the 28 day mechanical performance of cement pastes was not suppressed, and was found to be comparable to that of the control specimen. As an outcome, silica-coated structures can be successfully used in radiation-shielding cement-based composites, e.g. with demanding early age performances.National Science Centre of Poland within Project no. 2020/39/D/ST8/00975 (SONATA-16)

The trace fossil Lepidenteron lewesiensis: a taphonomic window on diversity of Late Cretaceous fishes

The trace fossil Lepidenteron lewesiensis (Mantell 1822) provides an exceptional taphonomic window to diversity of fishes as shown for the Upper Cretaceous of Poland, in the Middle Turonian–Lower Maastrichtian deposits of the Opole Trough, Miechów Trough, Mazury-Podlasie Homocline, and SE part of the Border Synclinorium. Lepidenteron lewesiensis is an unbranched burrow lined with small fish scales and bones, without a constructed wall. It contains scales, vertebrae, and bones of the head belonging to ten taxa of teleostean fishes: two undetermined teleosteans, six undetermined Clupeocephala, one Dercetidae, and one undetermined euteleostean. The preservation of fish remains suggests that fishes were pulled down into the burrow by an animal, probably by eunicid polychaetes.Das Spurenfossil Lepidenteron lewesiensis (Mantell 1822) ermöglicht einen biostratinomischen Einblick in die Diversität von Fischen, wie Fossilmaterial aus der Oberkreide von Polen zeigt. Es stammt aus dem Mittelturonium bis Untermaastrichtium des südöstlichen Abschnittes der Grenz-Synklinale, dem Opolen-Trog, dem Miechów-Trog und der Masuren-Podlachien-Homoklinale. L. lewesiensis ist ein unverzweigter Grabgang ohne ausgekleidete Wände, dessen Ränder von kleinen Fischschuppen und—knochen gebildet werden. Diese setzen sich aus Schuppen, Wirbel und Schädelknochen von zehn Teleostei-Taxa zusammen und zwar aus zwei unbestimmte Teleosteer, sechs unbestimmten Clupeocephala, einem Dercetidae und einem unbestimmten Euteleostei. Die Erhaltung der Fischüberreste deutet darauf hin, dass die Fische von einem Tier, wahrscheinlich einem Polychaeten der Familie Eunicidae, in den Bau gezogen wurden.We are very grateful to Dr. Lionel Cavin (Geneva) and the anonymous reviewer for constructive comments on an earlier version of the manuscript. Additional support was provided by the Jagiellonian University (DS funds), National Science Center (Grant Number: PRO-2011/01/N/ST10/07717), and the Laboratory of Geology (University of Lodz) BSt Grant No. 560/844. We are grateful to Dr. Johann Egger (Wien) and Kilian Eichenseer M.Sc. (Erlangen) for help with translating the abstract into German. We are grateful to Dr. Ursula Göhlich (Wien) for access to the Dercetis specimen

Review of electrostatic hazards in hard coal mining

Zagrożenia wywołane elektrycznością statyczną są zaliczane do zagrożeń technicznych występujących w górnictwie węgla kamiennego. Zagrożenia te związane są z powstaniem nadmiarowego ładunku elektrycznego, będącego skutkiem większości czynności technologicznych. Największe zagrożenie stanowią wyroby z tworzyw sztucznych, kwalifikowanych jako materiały nieantyelektrostatyczne. Omówiono regulacje europejskiego i polskiego prawa dotyczące wymagań dla materiałów w zakresie ich właściwości antyelektrostatycznych. Przedstawiono wyniki badań prowadzonych w GIG pod kątem usystematyzowania procesu antystatyzacji tworzyw sztucznych. Udowodniono, że proces nadania tworzywu sztucznemu właściwości antyelektrostatycznych nie jest łatwy i jednorodny. Wprowadzona systematyka procesu antystatyzacji, czyli identyfikacja różnych metod realizacji procesu antystatyzacji, ma na celu uświadomienie producentom i odbiorcom istnienia wielu, często niepożądanych, właściwości modyfikowanych tworzyw sztucznych.Electrostatic hazards are considered a category of technical hazards occurring in hard coal mining. These hazards are related to the generation of excess electric charges forming as a result of most technological processes. Products manufactured from plastics that are classified as non-antistatic materials pose the greatest hazard. The article discusses the Polish and European legal regulations concerning the requirements for materials regarding their antistatic properties. It also presents the results of studies conducted at GIG concerning the systematization of the antistatic processing of plastics. Furthermore, the article proves that the procedure of applying antistatic properties to plastics is neither easy nor homogeneous. The introduced antistatic processing systematics (i.e., the identification of various antistatic processing realization methods) is meant to make both the manufacturers and customers aware of the various (often undesired) properties of modified plastics

Przegląd zagrożeń od elektryczności statycznej w górnictwie węgla kamiennego

Electrostatic hazards are considered a category of technical hazards occurring in hard coal mining. These hazards are related to the generation of excess electric charges forming as a result of most technological processes. Products manufactured from plastics that are classified as non-antistatic materials pose the greatest hazard. The article discusses the Polish and European legal regulations concerning the requirements for materials regarding their antistatic properties. It also presents the results of studies conducted at GIG concerning the systematization of the antistatic processing of plastics. Furthermore, the article proves that the procedure of applying antistatic properties to plastics is neither easy nor homogeneous. The introduced antistatic processing systematics (i.e., the identification of various antistatic processing realization methods) is meant to make both the manufacturers and customers aware of the various (often undesired) properties of modified plastics.Zagrożenia wywołane elektrycznością statyczną są zaliczane do zagrożeń technicznych występujących w górnictwie węgla kamiennego. Zagrożenia te związane są z powstaniem nadmiarowego ładunku elektrycznego, będącego skutkiem większości czynności technologicznych. Największe zagrożenie stanowią wyroby z tworzyw sztucznych, kwalifikowanych jako materiały nieantyelektrostatyczne. Omówiono regulacje europejskiego i polskiego prawa dotyczące wymagań dla materiałów w zakresie ich właściwości antyelektrostatycznych. Przedstawiono wyniki badań prowadzonych w GIG pod kątem usystematyzowania procesu antystatyzacji tworzyw sztucznych. Udowodniono, że proces nadania tworzywu sztucznemu właściwości antyelektrostatycznych nie jest łatwy i jednorodny. Wprowadzona systematyka procesu antystatyzacji, czyli identyfikacja różnych metod realizacji procesu antystatyzacji, ma na celu uświadomienie producentom i odbiorcom istnienia wielu, często niepożądanych, właściwości modyfikowanych tworzyw sztucznych

Protection of Electronic Components against Static Electricity

W przeglądowym artykule omówiono różne problemy towarzyszące wyładowaniom elektrostatycznym, m.in. dotyczące bezpieczeństwa i komfortu człowieka, uszkodzeń podczas produkcji przyrządów elektronicznych w przemyśle oraz atmosfer wybuchowych w przemyśle podczas produkcji maszyn, a także dotyczące niebezpieczeństw występujących podczas badań medycznych. Opracowanie przedstawia system ochrony przed szkodliwymi wyładowaniami elektrostatycznymi, głównie w przemyśle elektronicznym wynikający z norm międzynarodowych.The publication contains an introduction to the various problems arising from electrostatic discharge. List the dangers of electrostatic discharges related to human safety and comfort, electronic defects in industrial electronics, explosive atmospheres in industry for the manufacture of various machines, and the dangers of medical research. The study presents a system of protection against harmful electrostatic discharge in the electronics industry resulting from international standards