Obtaining the steady shear rheological properties and apparent wall slip velocity data of a water-in-oil emulsion from gap-dependent parallel plate viscometry data

A two-stage Tikhonov regularisation procedure has been used to obtain rheological properties for a high internal phase emulsion from gap-dependent steady-state parallel plate shear data. This method is beneficial in that it can convert the steady shear data into rheological property functions. The built-in regularisation parameters of the method are able to keep noise amplification under control. The two-stage method is able to obtain not only the shear stress–shear rate function but also the apparent slip velocity as a function of wall shear stress. The method is such that it obtains the rheological functions over the maximum range of shear rate covered by the data. The results obtained using the new method are compared to those obtained using the vane geometry with good agreement being observed.     

Stationary patterns to diffusion problems

In this paper we are giving a complete account, as $\lambda\rightarrow\infty$\nopagenumbers\end , of all possible solutions u to the problem $u_{xx}+\lambda f(u)=0,\;u(0)=u(1)=0$\nopagenumbers\end which satisfy $0\leq u(x)\leq M\;\hbox{in}\; 0 < x<1$\nopagenumbers\end for some fixed $M>0$\nopagenumbers\end . A complete classification of them together with a detailed analysis of their limit profile, including exact location of ‘inner layers’, is given, their stability character is also determined. The analysis is completed by studying the cases where solutions u degenerate at zeros of f and considering also the p‐Laplacian version of the problem where the diffusion term is replaced by the operator $(|u_{x}|^{p‐2}u_x)_x,\;p>1$\nopagenumbers\end . Copyright © 2000 John Wiley & Sons, Ltd.     

Yellow-to-blue frequency upconversion in Pr-doped aluminium fluoride glasses

Rare-earth-doped fluoride glasses are attractive materials for photonics, since they combine a transmission region from ultraviolet to infrared and low vibrational cut-off energy. We report on the spectroscopic properties of aluminium fluorophosphate glasses doped with 0.1, 0.6, 1, 3 and 10 mol% Pr³⁺. Yellow-to-blue upconversion was observed upon pulsed and continuous-wave (CW) excitation at 575 nm. The temporal evolution of the upconverted fluorescence is characterised by rise and decay times depending on Pr³⁺ concentration. The upconversion intensity has a quadratic dependence on incident pump power, indicating a two-step process. The upconversion emission is described in the framework of a two-ion energy transfer mechanism. Emission in the second telecom window (1.3 μm) was measured upon excitation at 976 nm.     

Adsorption of SO2 from Wet Mixtures on Hydrophobic Zeolites

Breakthrough curve measurements of SO₂ and water vapor were carried out on a number of selected mordenite and pentasil zeolites from their binary and ternary mixtures with CO₂ at 50 and 100°C. SO₂ capacities of these samples were found to be significantly reduced by the presence of water. Competitive adsorption led to unusually high overshoot peaks of SO₂ breakthrough curves. On the other hand, SO₂ was found to displace water on the samples with very high silica to alumina ratio. A linear driving force, isothermal model was used to predict the breakthrough curves. Langmuir and extended Langmuir equilibrium models were used to describe the equilibrium properties of water and SO₂, respectively. The overall mass transfer resistance obtained from the model was compared to the values calculated from a simplified biporous adsorbent model to shed some light on the adsorption kinetics.     

N‐Benzoylthiourea

In the title compound, C₈H₈N₂OS, strong intramolecular N—H⋯O hydrogen bonds [N⋯O = 2.669 (3) and 2.618 (3) Å] form almost planar six‐membered rings and enforce the conformation of the mol­ecule. Two kinds of intermolecular N—H⋯S hydrogen bonds [N⋯S = 3.309 (3)–3.456 (2) Å] between two symmetry‐independent mol­ecules form consecutive dimers that expand in ribbons along the [100] direction.     

Evaluation of Innovative Dried Purée from Jerusalem Artichoke—In Vitro Studies of Its Physicochemical and Health-Promoting Properties

The present study aimed to evaluate the effect of Jerusalem artichoke processing methods and drying methods (freeze drying, sublimation drying, vacuum drying) on the basic physicochemical parameters, profiles and contents of sugars and polyphenolic compounds, and health-promoting properties (antioxidant activity, inhibition of the activities of α-amylase, α-glucosidase, and pancreatic lipase) of the produced purée. A total of 25 polyphenolic compounds belonging to hydroxycinnamic phenolic acids (LC-PDA-MS-QTof) were detected in Jerusalem artichoke purée. Their average content in the raw material was at 820 mg/100 g dm (UPLC-PDA-FL) and was 2.7 times higher than in the cooked material. The chemical composition and the health-promoting value of the purées were affected by the drying method, with the most beneficial values of the evaluated parameters obtained upon freeze drying. Vacuum drying could offer an alternative to freeze drying, as both methods ensured relatively comparable values of the assessed parameters.     

Toxicological determination and in vitro metabolism of the designer drug methylenedioxypyrovalerone (MPDV) by gas chromatography/mass spectrometry and liquid chromatography/quadrupole time‐of‐flight mass spectrometry

A method for the toxicological screening of the new designer drug methylenedioxypyrovalerone (MDPV) is described; with an emphasis on its application for anti‐doping analysis. The metabolism of MDPV was evaluated in vitro using human liver microsomes and S9 cellular fractions for CYP450 phase I and uridine 5′‐diphosphoglucuronosyltransferase (UGT) and sulfotransferase (SULT) phase II metabolism studies. The resulting metabolites were subsequently liquid/liquid extracted and analyzed using gas chromatography/mass spectrometry (GC/MS) as trimethylsilyl (TMS) derivatives. The structures of the metabolites were further confirmed by accurate mass measurement using a liquid chromatography/quadrupole time‐of‐flight (LC/QTOF) mass spectrometer. The studies demonstrated that the main metabolites of MDPV are catechol and methyl catechol pyrovalerone, which are in turn sulfated and glucuronated. The method for the determination of MDPV in urine has been fully validated by assessing the limits of detection and quantification, linearity, repeatability, and accuracy. This validation demonstrates the suitability for screening of this stimulant substance for anti‐doping and forensic toxicology purposes. Copyright © 2010 John Wiley & Sons, Ltd.     

Effective permittivity of a fiber-reinforced composite with transversely isotropic constituents

Simple closed-form expressions for effective permittivity of fiber-reinforced composites with transversely isotropic constituents are found using asymptotic homogenization. Circular cylindrical fibers are distributed in a square array. The analysis considers four orientations of constituents transverse symmetry axis relative to fibers direction. Local problems defined on a periodic square unit cell are solved by means of complex potential theory using Weierstrassian and Natanzon's functions, assuming that the contrast of permittivities is small. Derived closed-form formulas are compared with finite element calculations and, in the isotropic case, with standard mixture rules and classical bounds, obtaining excellent results even when contrast is large.