Dynamic mechanical thermal analysis of aqueous sugar solutions containing fructose, glucose, sucrose, maltose and lactose

The glass transition of glucose, fructose, lactose, maltose and sucrose solutions at maximum cryo-concentration was studied by Dynamic Mechanical Thermal Analysis (DMTA), using the disc bending technique. The glass transition temperatures were determined from the peaks in the loss modulus E′′, which corresponds theoretically to the resonance point (Maxwell model) for several input frequencies. The frequency dependence was well described by both an Arrhenius-type model and by the WLF (Williams, Landel and Ferry) equation, yielding glass transition temperatures for an average molecular vibration time of 100 s, which were similar to published midpoint temperatures determined by DSC scans. Some sugar mixtures were studied, yielding results that were well described by the Gordon–Taylor equation, using literature data. The frequency dependence of the viscoelastic ratio was also well approximated by an Arrhenius-type equation, with activation energies similar to those of the glass transition temperature and corresponded well to published values of the endset of glass transition

Mid-IR plasmonics and photomodification with Ag films

The optical properties of semicontinuous silver films have been studied in the mid infrared. The film extinction spectra are shown to be well tailored by the deposition conditions and post-fabrication photomodification with both nanosecond and picosecond laser pulses at 10.6 mu m. The photomodification results in a decrease of the extinction above the laser wavelength. We find that the induced changes in the optical responses of the films are both wavelength and polarization selective. This technique allows the creation of long-pass filters for the mid-IR range in accord with the earlier theory

Characterization of the physical state of spray-dried inulin.

Modulated differential scanning calorimetry, wide angle x-ray scattering, and environmental scanning electron microscopy were used to investigate the physical and morphological properties of chicory root inulin spray dried under different conditions. When the feed temperature increased up to 80 degrees C, the average degree of polymerization of the solubilized fraction increased, leading to a higher glass transition temperature (Tg). Above 80 degrees C, the samples were completely amorphous, and the Tg did not change. The starting material was semicrystalline, and the melting region was composed of a dual endotherm; the first peak subsided as the feed temperature increased up to a temperature of 70 degrees C, whereas above 80 degrees C, no melting peak was observed as the samples were completely amorphous. To a lesser extent, the inlet air temperature of 230 degrees C allowed a higher amorphous content of the samples than at 120-170 degrees C but induced a blow-out of the particles