Transient time in homogeneous nucleation

The problem of the transient time in nucleation is studied. The size-dependent transient time at a constant temperature is defined and the approximate analytical solution is found and compared with the exact numerical solution for the model Li₂O.2 SiO₂ melt. It is shown that the analytical solution for the size-dependent transient time is in agreement with the numerical result.     

Application of 1,10-phenanthroline for preconcentration of selected heavy metals on silica gel

Stripping voltammetry analysis using a hemispheroidal mercury microelectrode has been previously assessed theoretically as a possible candidate ‘primary method’ for amount of substance measurement. It was shown that the measurement methodology can be described completely by a set of measurement equations when a novel quantification process is employed to measure the steady-state diffusion-limited deposition current over an optimum sampling time, instead of employing an analyte stripping step. The corollary is that, for solutions of known composition, the method may be used for highly accurate determination of diffusion coefficients. This investigation uses experimental data from steady-state diffusion-limited current measurements with sampling periods optimised using Allan deviation techniques, together with a full uncertainty analysis to estimate feasibility and likely accuracy of this method.     

Equivalence of closed 1-forms on surfaces with edge

We investigate closed 1-forms with isolated zeros on surfaces with edge. A criterion for the topological equivalence of closed 1-forms is proved.     

Non-stationary crystallization in simple glass-forming materials

A crystal distribution function is established during the crystallization process of simple glass-forming melts on the basis of the numerical computation of the kinetic equation in a non-stationary regime for constant and non-constant temperature. Nucleation rate and time-temperature-transformation curves are determined from the calculations of the crystal distribution function at various constant temperatures for various parameters of the system (the dependence on the difference of the chemical potentials, the dependence on the surface energy etc.).     

Isotope dilution analysis in column-coupling isotachophoresis

The use of isotope dilution technique to eliminate problems associated with demands for a high load capacity in column-coupling capillary isotachophoresis was studied. Determinations of phosphate present in a model mixture and in white wine served for the evaluation of this approach to quantitative analysis in isotachophoresis. A high selectivity of the analysis with acceptable accuracy and precision of the determination also in complex ionic mixtures in a short time are obvious advantages of this approach.     

Nanotubes Made from Deeply Undercooled Cryolite/Alumina Melts

The rapid‐solidification processing (by a cooling rate of 10⁵–10⁶ K/s) was used for the preparation of deeply undercooled cryolite/alumina (Na₃AlF₆/Al₂O₃) melts. We found a mass of nanotubes on the surface of these undercooled melts. The nanotubes were preferentially located on the defect places of the surface with the following approximate dimensions: base≈100×100 nm, length≈1000 nm. The solidified samples with the nanotubes on the surface were analyzed by scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), X‐ray diffraction (XRD), and infrared spectroscopy (IR).