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...

When a capillary is inserted into a liquid, the liquid will rapidly flow into it. This phenomenon, well studied and understood on the macroscale, is investigated by molecular dynamics simulations for coarse-grained models of nanotubes. Both a simple Lennard-Jones fluid and a model for a polymer melt are considered. In both cases after a transient period (of a few nanoseconds) the meniscus rises...

The goal of this effort is to provide an accurate simulation of multifilament fiber melt spinning, applicable for a wide range of material and process conditions. For ease of use, the model should run on a standard laptop or desktop computer in reasonable time (one hour or less). Most melt spinning models simulate the formation of a single filament, with little or no attention given to multifil...

A mathematical model for the free radical polymerization of styrene is developed to predict the steady-state and dynamic behavior of a continuous process. Special emphasis is given for the kinetic and thermodynamic models, where the most sensitive parameters were estimated using data from an industrial plant. The thermodynamic model is based on a cubic equation of state and a mixing rule applie...

The aim of this study was to produce isotactic polypropylene based composites filled with waste thermosetting bulk moulded composite (BMC). The influence of BMC waste addition (5, 10, 20 wt%) on composites structure and properties was investigated. Moreover, additional studies of chemical treatment of the filler were prepared. Modification of BMC waste by calcium stearate (CaSt) powder allows t...

10 The Earth’s deep interior contains significant reservoirs of volatiles such as H, C, and N. Due 11 to the incompatible nature of these volatile species, it has been difficult to reconcile their 12 storage in the residual mantle immediately following crystallization of the terrestrial magma 13 ocean (MO). As the magma ocean freezes, it is commonly assumed, very small amounts 14 of melt is ret...

We study the formation mechanism of rims created around femtosecond laser-ablated craters on glass. Experimental studies of the surface morphology reveal that a thin rim is formed around the smooth craters and is raised above the undamaged surface by about 50-100 nm. To investigate the mechanism of rim formation following a single ultrafast laser pulse, we perform a one-dimensional theoretical ...

Molecular dynamics computer simulations are used to investigate a silica melt confined between walls at equilibrium and in a steady–state Poisseuille flow. The walls consist of point particles forming a rigid face–centered cubic lattice and the interaction of the walls with the melt atoms is modelled such that the wall particles have only a weak bonding to those in the melt, i.e. much weaker th...

Melt spinning of polypropylene nonwoven nanofiber mats is demonstrated using Forcespinning The effects of rotational speed and melt flow rate of polymer on fiber diameter were studied. It was observed that melt flow rate of the polymer plays a major role in nanofiber formation and uniformity. Differential scanning calorimetry and X-Ray Diffraction analysis indicate that the crystallinity of nan...