Optimization of the dynamic blanking process

In this paper an optimization of the dynamic blanking process with using E–PLANNER, ANSYS and MATLAB programmes was presented. The main aim of this work was to obtain the high quality of the cut surface in function of: the size of clearance between punch and die, value of fillet radius of the punch edge and the speed of blanking. Numerical analysis were conducted in Ansys LS–Dyna programme, with use of the explicit method and the experiment plan had been done before. Five levels rotary plan, was used. Unknown coefficients in mathematical model in the shape of quadratic equation with interactions were obtained. Obtained regression function was optimized in MATLAB programme, and determined optimal value of the process parameters. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Ferroelectric properties of ultrasonochemically prepared SbSI ethanogel

This article presents for the first time the electrical properties of sonochemically synthesised, high-surface-area SbSI ethanogel made up of large quantity nanowires with lateral dimensions of about 10-50 nm and lengths reaching up to several micrometers. The composition, morphology, dimensions, microstructures, and optical energy gap of the new form of SbSI were characterized. This material is a semiconducting ferroelectric as in the case of bulk SbSI crystals. The maximum of dielectric constant epsilon=1.6x10(4) is observed at Tc=292(1) K. The activation energies in temperature dependences of electric conductivity of SbSI ethanogel are different for ferroelectric and paraelectric phases during heating and cooling of the sample.     

A close look at short C-CH3...potassium contacts: synthetic and theoretical investigations of [M2Co2(mu3-OtBu)2(mu2-OtBu)4(thf)n] (M = Na, K, Rb, thf = tetrahydrofuran)

Agostic interactions of the type Si-CH3M+ (M = alkali metal) are frequently mentioned in discussions of solid-state structures of trimethylsilyl compounds and the purpose of this work was to elucidate if they also exist in the related tert-butyl species by using density functional theory. The compounds [M2Co2(mu3-OtBu)2(mu2-OtBu)4(thf)n] (M = Na, n = 2; M = K, n = 0; M = Rb, n = 1) have been synthesised and their crystal structures determined. Close contacts of methyl groups with K atoms are observed in the solid-state structure of [K2Co2(mu3-OtBu)2(mu2-OtBu)4], and calculations of the rotational barrier of a tert-butoxy group about the axis through the C-O bond were performed. It was shown that apparent short C-CH3K distances are in this case a consequence of the packing in the extended solid-state structure.     

Quantized electron accumulation states in indium nitride studied by angle-resolved photoemission spectroscopy

Electron accumulation states in InN have been measured using high resolution angle-resolved photoemission spectroscopy (ARPES). The electrons in the accumulation layer have been discovered to reside in quantum well states. ARPES was also used to measure the Fermi surface of these quantum well states, as well as their constant binding energy contours below the Fermi level E(F). The energy of the Fermi level and the size of the Fermi surface for these quantum well states could be controlled by varying the method of surface preparation. This is the first unambiguous observation that electrons in the InN accumulation layer are quantized and the first time the Fermi surface associated with such states has been measured.     

Vibro-acoustic method for estimating a liquid level and viscosity

The goal of this work has been to examine a possibility to measure a liquid level and its viscosity by the vibro-acoustic methods. Preliminary laboratory investigations were completed on a glass vessel filled with solutions of various viscosity and level, excited by a hammer. A microphone and four accelerometers were used as sensors. Few criteria symptoms were checked. For the level and viscosity estimation there were used the placement and values of the Fourier's spectra maximum of the acoustic signal, and of the vibration signals from sensors. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Isotope effects accompanying evaporation of water from leaky containers

Laboratory experiments aimed at quantifying isotope effects associated with partial evaporation of water from leaky containers have been performed under three different settings: (i) evaporation into dry atmosphere, performed in a dynamic mode, (ii) evaporation into dry atmosphere, performed in a static mode, and (iii) evaporation into free laboratory atmosphere. The results demonstrate that evaporative enrichment of water stored in leaky containers can be properly described in the framework of the Craig-Gordon evaporation model. The key parameter controlling the degree of isotope enrichment is the remaining fraction of water in the leaking containers. Other factors such as temperature, relative humidity, or extent of kinetic fractionation play only minor roles. Satisfactory agreement between observed and predicted isotope enrichments for both (18)O and (2)H in experiments for the case of evaporation into dry atmosphere could be obtained only when molecular diffusivity ratios of isotope water molecules as suggested recently by Cappa et al. [J. Geophys. Res., 108, 4525-4535, (2003).] were adopted. However, the observed and modelled isotope enrichments for (2)H and (18)O could be reconciled also for the ratios of molecular diffusivities obtained by Merlivat [J. Chem. Phys., 69, 2864-2871 (1978).], if non-negligible transport resistance in the viscous liquid sub-layer adjacent to the evaporating surface is considered. The evaporation experiments revealed that the loss of mass of water stored in leaky containers in the order of 1%, will lead to an increase of the heavy isotope content in this water by ca. 0.35 and 1.1 per thousand, for delta (18)O and delta (2)H, respectively.     

Activation and Deactivation of Gold/Ceria–Zirconia in the Low-Temperature Water–Gas Shift Reaction

Gold (Au) on ceria–zirconia is one of the most active catalysts for the low-temperature water–gas shift reaction (LTS), a key stage of upgrading H₂ reformate streams for fuel cells. However, this catalyst rapidly deactivates on-stream and the deactivation mechanism remains unclear. Using stop–start scanning transmission electron microscopy to follow the exact same area of the sample at different stages of the LTS reaction, as well as complementary X-ray photoelectron spectroscopy, we observed the activation and deactivation of the catalyst at various stages. During the heating of the catalyst to reaction temperature, we observed the formation of small Au nanoparticles (NPs; 1–2 nm) from subnanometer Au species. These NPs were then seen to agglomerate further over 48 h on-stream, and most rapidly in the first 5 h when the highest rate of deactivation was observed. These findings suggest that the primary deactivation process consists of the loss of active sites through the agglomeration and possible dewetting of Au NPs.     

Christmas Tree Bio-Waste as a Power Source of Bioactive Materials with Anti-Proliferative Activities for Oral Care

According to the American Cancer Society, roughly 54,000 new cases of oral cavity or oropharyngeal cancers have been detected in the United States of America in 2021, and they will cause about 10,850 deaths. The main therapies for cancer management, such as surgery and radio- and chemotherapy, have some own benefits, albeit they are often destructive for surrounding tissues; thus, deep investigations into non-surgical treatments for oral cavities are needed. Biologically active compounds (BACs) extracted from European Spruce needles were analyzed to determine the total phenolic and flavonoid content and were used as additional ingredients for oral hygiene products. An anti-proliferation investigation was carried out using extracts containing BACs with the use of several cell lines (cancer and a normal one). ESI-MS studies on BACs showed that luteolin, a natural flavonoid compound with anti-tumorigenic properties against various types of tumors, is the predominant component of the extracts. MTT, BrdU, and LIVE/DEAD studies demonstrated that BAC extracts obtained from Christmas tree needles possess anticancer properties against squamous cell carcinoma (with epithelial origins). We proved that BAC extracts contain high amounts of luteolin, which induces cytotoxicity toward cancer cells; along with their high selectivity, robustness, and nontoxicity, they are very promising materials in oral health applications.