The GaAs wafer market is characterised by an increasing demand on high-quality substrates ready for epitaxial post-processing. Nowadays, advanced Vertical Bridgman (VB) growth variants such as the Vertical Gradient Freeze (VGF) technique, are preferentially employed to meet the strong requirements according to a low dislocation density and high homogeneity of the substrates. By combining the VG...

Aspartic acid is prepared chemically or by the fermentation of carbohydrates. Currently, low molecular weight polyaspartic acids are prepared commercially by heating aspartic acid at high temperatures (>220 C) for several hours in the solid state. In an effort to develop a more rapid, continuous, melt polymerization scheme, aspartic acid was copolymerized with adipic, azelaic, sebacic, and dode...

[1] Anelasticity and diffusion creep viscosity of partially molten rock analogue were measured experimentally at various melt fractions (0.0025–0.04). The presence of even a small quantity of melt phase causes a significant increase in attenuation and dispersion, and decrease in viscosity (melt effect). Similar changes are additionally caused by the presence of a secondary solid component (chem...

Melts of commercial high-density polyethylene (M — w = 36–85 6 10) were subjected to the hydrodynamics of a Haake Rheocord blender at temperatures (T) spanning the normal processing range (190–2608C), far beyond the disappearance of solid crystals at about 1408C. Torque measurements revealed a peculiar dependence on T, including transitions at about 2088C and 2278C, and non-Arrhenius behavior a...

Environmental and processing factors affecting the biostability of medical devices made from traditionally "stable" polymers, such as isotactic polypropylene (PP) and ultrahigh molecular weight polyethylene (UHMW-PE) , were analyzed and their undesirable degradation was related to performance of typical medical devices. Among the critical phenomena determining the biological performance of UHMW...

Polymer melts are highly-viscous non-Newtonian fluids. The manufacture of an article from polymer involves heating, shaping and cooling processes. The rheology of the polymer melt is considered to be one of the most important factors in determining the properties of a polymer product, the properties being related to the flow and deformation of the fluid particles in the processing equipment. Th...

In this paper, the benefit of numerical simulation for the development of a special crystal growth technique for the processing of silicon wafers for photovoltaic applications on an industrial scale is demonstrated, as an example for the importance of numerical simulation for industrial processing of bulk semiconductor crystals in general. Depending on the complexity of the problems to be treat...

At low temperatures (<750 °C at moderate to high crustal pressures), the production of suffi cient melt to reach the melt connectivity transition (~7 vol%), enabling melt drainage, requires an infl ux of aqueous fl uid along structurally controlled pathways or recycling of fl uid via migration of melt and exsolution during crystallization. At higher temperatures, melting occurs by fl uid-absent...

Two high melt episodes occurred on the Greenland ice sheet in July 2012, during which nearly the entire ice sheet surface experienced melting. Observations from an automatic weather station (AWS) in the lower ablation area in South Greenland reveal the largest daily melt rates (up to 28 cm d−1 ice equivalent) ever recorded on the ice sheet. The two melt episodes lasted 6 days, equivalent to 6% ...

In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: a b s t r a c t a r t i c l e i n f o Under typical glass-processing conditions, crystals nucleate, grow, and dissolve in a ...