Nucleation parameters for polymer crystallization from non-isothermal thermal analysis

Differential scanning calorimetry (DSC) has been used to obtain kinetic and nucleation parameters for polymer crystallization under a non-isothermal mode of operation. The available isothermal nucleation growth-rate equation has been modified for non-isothermal kinetic analysis. The values of the nucleation constant (K g ) and surface free energies (sgr, sgr e ) have been obtained for i-polybutene-1, i-polypropylene, poly(L-lactic acid), and polyoxymethylene and are compared with those obtained from isothermal kinetic analysis; a good agreement in both is seen.

Exterior of old synagogue; Hochberg Synagogues; Exterior

Digital Image

Garden gate to Daijas' father's house Architecture; Residences; Exterior

Verso: Das Gartentor zu Daijas Vaterhaus Georg lebete um die Ecke

Exterior view of Schoenbeck residence; Stadtoldendorf, Germany.

Photo owned by Annette Rochaix, Belmont Switz. Deposited: Archiv Cantonales, Remens, Switz. Copy by T. Krakauer

The rα structure, chemical shift anisotropy, and the abnormal orientation of methyldichlorophosphine from the NMR spectrum

NMR studies of methyldichlorophosphine have been undertaken in the nematic phase of mixed liquid crystals of opposite diamagnetic anisotropies. The rα structure is derived. The proton chemical-shift anisotropy has been determined from the studies without the use of a reference compound and without a change of experimental conditions. It is shown that the molecule orients in the liquid crystal with positive diamagnetic anisotropy in such a way that the C3 symmetry axis of the CH3P moiety is preferentially aligned perpendicular to the direction of the magnetic field, unlike other similar systems. This is interpreted in terms of the formation of a weak solvent-solute molecular complex. The heteronuclear indirect spin-spin coupling constants are determined. The sign of the two-bond JPH is found to be positive.

Effect of experimental parameters on non-isothermal TG

The effect of some experimental parameters, namely sample weight, particle size and its distribution, heating rate and flow rate of inert gas, on the fractional decomposition of calcium carbonate samples have been studied both experimentally and theoretical. The general conclusions obtained from theoretical analysis are corroborated qualitatively by the experimental data. The analysis indicates that the kinetic compensating effect may be partly due to the variations in experimental parameters for different experiments.

Exterior of the A. Godshaw Jewelry Store; Welwyn Garden City.

The store moved to larger quarters in the 1990s.

Exterior of the A. Godshaw Jewelry Store; Welwyn Garden City.

The store moved to larger quarters in the 1990s.

Exterior view of Gottschalk residence; Seelhorst Strasse 27, Hannover, Germany.

Fig. 13 in family portrait

Exterior view of store J. Meyerhof am Platze; Hildesheim, Germany.

The photograph was taken in the late 19th century or early 20th century before the streetcar tracks were laid and a third floor added to the store. Members of the Meyerhof family lived in the 3rd floor apartment. Note the faces of the seamstresses on the second floor who were producing sheets, etc.

Exterior view of store J. Meyerhof am Platze; Hildesheim, Germany.

The photograph was taken in the late 19th century or early 20th century before the streetcar tracks were laid and a third floor added to the store. Members of the Meyerhof family lived in the 3rd floor apartment. Note the faces of the seamstresses on the second floor who were producing sheets, etc.