Modeling of Drying of Highly Shrinking Materials Using Hydrogels as an Example

The work presents a model of convective drying of a highly shrinking material of cylindrical shape. To identify the effective diffusivity as a function of local temperature and moisture content the problem was solved as an inverse problem. A set of experimental data served for model validation. The optimization algorithms were used to solve PDE system and fit numerically obtained curves to the experimental data using the effective diffusivity as the only adjustable parameter.     

X-ray characterization of SnTe: Gd crystal

Electron probe microanalyses were performed on SnTe crystal grown by the Bridgman method doped with 1.8 wt% Gd. Scanning electron microscopic observations and electron probe microanalysis carried out on the (110) and (100) oriented samples revealed two types of precipitate enriched in gadolinium. It was suggested that the dominant type contained a mixture of Gd₄Te₇ phase and Te_0.8Gd_0.2 eutectic. The composition of the second precipitate type was found to be a eutectic enriched with gadolinium.     

Influence of hydrodynamics of rotary dynamic filters on separation processes

The fluid flow in a filter chamber, consisting of a rotating disk and a stationary plate, has been numerically investigated. A proposed model provided acceptable predictions for shear rate and frictional torque in laminar and turbulent flow regimes. Owing to the pronounced effect of the shear stress on the filtration rate, the data obtained were used in analysis of the influence of hydrodynamics on the shear stress field in the filter chamber.     

Energieeinsparung durch Anwendung von Absaugsystemen mit veränderlichem Luftverbrauch in der Holzindustrie

Exhaustion installations are characterized by high energy consumption. Energy costs can be reduced by installation of exhaustion systems using a variable air flow. Calculations based on a practical example demonstrate that remarkable results can be achieved using this system.     

Theory of paramagnetic spin waves in simple metals in a direct-current magnetic field

The transverse dynamic spin susceptibility of a normal, charged Fermi liquid is found. The formula depends on the first three antisymmetric Landau parametersB ₀,B ₁,B ₂ and is exact to orderk ² in the expressions both for the energy of spin waves and their oscillator strengths. It contains spin-wave poles with1=0 and 1 and easily reproduces all the results obtained previously by perturbation theory.On leave of absence from: Institute of Physics, University of Lattakia, Syria.     

Low-temperature anisotropy of thermal conductivity of tin single crystals doped with zinc

The thermal conductivity of tin single crystals with zinc admixtures has been measured in the temperature range 3.5–25 K for concentrations up to 0.1 wt%. The anisotropy of thermal conductivity for two orientations, [001] and [010], has been determined. It was found that the influence of zinc admixture on the thermal conductivity anisotropy is of a complex, temperature-dependent character.Nomenclature T ₁ T ₂ Temperature differences in the specimen - Thermal conductivity coefficient - W Thermal resistivity - A, B, C Constants in Eq. (1) - T Temperature - ^th Residual electrical resistivity calculated from W-F law - ₀ Residual electrical resistivity from measurements - L ₀ Lorenz constant - _th Anisotropy coefficient of thermal conductivity - _el Anisotropy coefficient of electrical conductivity - c Admixture concentration     

The mechanism of continuous dissolution of the lamellar structure in aged Al 22 at% Zn alloy

The mechanism of continuous dissolution was studied using transmission electron microscopy, X-ray diffraction and hardness measurements. The metastable phase was identified in the first stage of dissolution nucleating at the - boundaries. Interface dislocations at the - boundaries forming a perpendicular net in the 110 directions were identified as of screw character and of Burgers vector b=1/2a 110. During dissolution a change of shape of precipitates occurs leading to their fragmentation and to a change of the direction of boundaries into 110 directions.     

On Hautus-type conditions for controllability of implicit linear discrete-time systems

Four notions of controllability for general (i.e., possibly nonregular) implicit linear discrete-time systems are considered. Relationships between them are studied. A Hautus-type characterization of all of these notions is also given.This work was performed under the auspices of RP.I.02: Teoria sterowania i optymalizacji ciagych ukadów dynamicznych i procesów dyskretnych.     

Novel 7‐maleimido‐2(1H)‐quinolones as potential fluorescent sensors for the detection of sulphydryl groups

Novel compounds, based on the 2(1H)‐quinolone skeleton, were synthesised and characterised using ¹H‐nuclear magnetic resonance (NMR) spectroscopy and chemical ionisation mass spectrometry (CI MS). Their spectroscopic properties, such as absorption and emission spectra and fluorescence quantum yield, were also examined. 7‐maleimido‐4‐methyl‐2(1H)‐quinolone, 7‐maleimido‐3,4‐dimethyl‐2(1H)‐quinolone, 7‐maleimido‐4‐propyl‐2(1H)‐quinolone and 7‐maleimido‐4‐phenyl‐2(1H)‐quinolone were evaluated as potential sensors for the detection of sulphydryl amino acids groups. These new compounds demonstrate a high ‘turn‐on’ fluorescence response and selectivity towards l ‐cysteine in the presence of other amino acids and metal cations.