Authors:P. Mokrejs, F. Langmaier, D. Janacova, M. Mladek, K. Kolomaznik, and V. Vasek
The study deals with the effect of chemical and physical modifications on thermal properties and solubility properties of
films based on amaranth flour starch–protein hydrolysate. Biodegradable and edible films were prepared by casting a 25% (w/w)
solution of hydrolysate containing 20% glycerol and various additions of dialdehyde starch (0, 1 and 5%). After thermal exposure
of films at 65 and 95 °C (for 6 and 48 h), thermal properties of films were studied employing differential scanning calorimetry
and thermogravimetric analysis. Film solubility tests were performed in an aqueous environment at 25 °C. Chemical and physical
modifications of films markedly affect their thermal properties and solubility.
Authors:M. Böttger, D. Birnstein, W. Helbig, and S. Niese
A sensitive method of carbon determination in silicon by activation with deuterons and3He particles followed by chemical separation of the measured nuclides13N and11C has been developed. Aside from the etch removal after irradiation, it is essential for a low detection limit to avoid too
much thermal exposure of the target surface during the irradiation process, or else microflaw formation and diffusion on the
surface have to be anticipated. The ion current must have an optimal rather than a maximum value.
DSC analysis is applied to investigate the precipitation reaction in the AA6005 extrusion alloy for different heat treatment
practices often presented in commercial production. The quenching practice is shown to have a big impact on the response of
the AA6005 alloy to an artificial ageing treatment. The range of β″ precipitation is displaced to lower temperatures in samples
quenched in air following the solution treatment. This acceleration, however, does not produce a favorable effect on age hardening
capacity since much of the solute Mg and Si is removed from the solid solution before the principal hardening phase can precipitate.
The DSC results are in good agreement with the age hardening curves. Natural ageing before artificial ageing promotes clustering
activities during a subsequent thermal exposure and produces a strong delay in β″ precipitation.
Authors:P. Hsu, C. Souers, M. De Haven, R. Garza, J. Alvarez, and J. Maienschein
Thermal damage was applied to LX-17 at 190°C for several hours. The damaged LX-17 samples, after cooled down to room temperature,
were characterized for their material properties, safety and performance. Mass losses upon thermal exposure were insignificant
(<0.1 mass%). The damaged LX-17 samples expanded, resulting in a bulk density reduction of 4.3%. Subsequent detonation measurements
(cylinder tests) were conducted on the thermally-damaged LX-17 samples. The results showed that the fractions of damaged LX-17
reacted were slightly lower than those of pristine LX-17. The thermally damaged LX-17 samples had average detonation velocity
of 7.341 mm μs−1, lower than that (7.638 mm μs−1) of pristine LX-17. The average detonation energy density for the damaged LX-17 was 5.18 kJ cm−3, about 6.0% lower than the detonation energy density of 5.51 kJ cm−3 for the pristine LX-17. The break-out curves showed reaction zone lengths for pristine LX-17 and damaged LX-17 were similar
but the damaged samples had ragged detonation fronts. DSC curves showed no significant difference between pristine LX-17 and
damaged LX-17 with a peak temperature of 381°C observed.
crystallization behaviour of polylactic acid (PLA) and a clay nanocomposite
of have been examined using differential scanning calorimetry. The data obtained
clearly indicates that the presence of the nanocomposite particles in the
composite material influences the crystallization kinetics of the PLA when
crystallized both from the solid amorphous state as well as from the melt.
When crystallized from the melt the presence of the clay nano-particles appears
to be influencing the nucleation and crystal growth rate of the PLA such that
the crystallization rate is enhanced by a factor of about 15 to 20. This result
is of tremendous significance in identifying the processing window for the
production of foamed nanocomposites from PLA. In addition the effect of thermal
exposure at 200C on the crystallization behaviour of these materials
has been investigated, with the results suggesting that holding these materials
at 200C for periods of time up to 60 min in an inert atmosphere only
has a marginal effect.
Authors:Javier Romualdez, Xiao Huang, Rick Kearsey, and Qi Yang
partially stabilized state ( t′ phase) with 7 wt% (3.9 mol%) yttria [ 2 ]. However, the stability of the partially stabilized zirconia diminishes over time during thermalexposure, resulting in the recurrence of the m phase.
Addition of tertiary
Authors:Vadim V. Krongauz, Yann-Per Lee, and Anthony Bourassa
yielded very clear temperature and time of thermalexposure dependent series of absorption spectra ( Fig. 2 ).
Change in appearance of DEHP-plasticized PVC films upon exposure to 200 °C. Exposure time (minutes