At-line porosity sensing for non-destructive disintegration testing in immediate release tablets.

Fully automated at-line terahertz time-domain spectroscopy in transmission mode is used to measure tablet porosity for thousands of immediate release tablets. The measurements are rapid and non-destructive. Both laboratory prepared tablets and commercial samples are studied.

Interactions and binding energies of dimethyl methylphosphonate and dimethyl chlorophosphate with amorphous silica.

The fundamental interactions of dimethyl methylphosphonate (DMMP) and dimethyl chlorophosphate (DMCP) on amorphous silica nanoparticles have been investigated with transmission infrared spectroscopy and temperature-programmed desorption (TPD). DMMP and DMCP both adsorb molecularly to silica through the formation of hydrogen bonds between isolated silanols and the phosphoryl oxygen of the adsorbate. The magnitude of the shift of the ν(OH) mode upon simulant adsorption is correlated to the adsorption strength.

The mathematical origins of the kinetic compensation effect: 2. The effect of systematic errors.

The kinetic compensation effect states that there is a linear relationship between Arrhenius parameters ln A and E for a family of related processes. It is a widely observed phenomenon in many areas of science, notably heterogeneous catalysis. This paper explores mathematical, rather than physicochemical, explanations for the compensation effect in certain situations.

The mathematical origins of the kinetic compensation effect: 1. The effect of random experimental errors.

The kinetic compensation effect states that there is a linear relationship between Arrhenius parameters ln A and E for a family of related processes. It is a widely observed phenomenon in many areas of science, notably heterogeneous catalysis. This paper explores one of the mathematical, rather than physicochemical, explanations for the compensation effect and for the isokinetic relationship.

Analysis of temperature programmed desorption (TPD) data for the characterisation of catalysts containing a distribution of adsorption sites.

This paper discusses some methods of analysing TPD data for samples obeying first-order desorption kinetics and proposes several improvements to existing practice. The methods apply in the case when the Arrhenius parameters A and E for each site are independent of coverage, and thus are normally suitable for the characterisation of porous solids. An improved implementation of the condensation approximation method is proposed to gain an initial estimate of the adsorption site distribution.

Complexes of Zn(2+), Cd(2+), and Hg(2+) with 2-(alpha-Hydroxybenzyl)thiamine Monophosphate Chloride.

The binding sites of Zn(2+), Cd(2+), and Hg(2+) in complexes with 2-(alpha-hydroxybenzyl)thiamine monophosphate chloride, (LH)(+)Cl(-), have been investigated in the solid state [2-(alpha-hydroxybenzyl)thiamin monophosphate chloride monoprotonated at the phosphate group and protonated at N(1)' is denoted as (LH)(+)Cl(-); therefore, the ligand monoprotonated at the phosphate group and deprotonated at N(1)' is L]. Complexes of formulae MLCl(2), M(LH)Cl(3), and (MCl(4))(2)(-)(LH)(2)(+) (M = Zn(2+), Cd(2+), and Hg(2+)) were isolated in aqueous and methanolic solutions, depending on pH. The crystal structure of the complex of formula HgL(2)Cl(2) was solved, together with that of the free ligand (LH)(+)Cl(-), by X-ray crystallography.

Solid State Dynamics of Tricarbonyl(eta-1,5-cyclohexadienylium)iron Tetrafluoroborate and Tricarbonyl(eta-1,5-cycloheptadienylium)iron Tetrafluoroborate.

The dynamic behavior of [(C(6)H(7))Fe(CO)(3)]BF(4) (I) and [(C(7)H(9))Fe(CO)(3)]BF(4) (II) in the solid state has been investigated principally by NMR spectroscopy. High-resolution variable-temperature (1)H and (13)C NMR spectra indicate that both complexes have a solid state phase transition above which there is rapid reorientation of the cyclodienylium rings and fast exchange of the carbonyl groups. The transition occurs between 253 and 263 K for I and between 329 and 341 K for II.