Sintered Halon G-80, a polytetrafluoroethylene (PTFE) resin available commercially in powdered form, is a superb diffuse reflector. Sintered Halon has > 96% absolute reflectance at wavelengths between 300 nm and 380 nm, and about 98% absolute reflectance above 380 rim. It is chemically inert, is mechanically strong, does not fluoresce, and the high reflectance is e&~y to maintain over time. We ...

The initial stages of solidification near the meniscus during continuous casting of steel slabs involve many complex inter-related transient phenomena, which cause periodic oscillation marks (OMs), subsurface hooks, and related surface defects. This article presents a detailed mechanism for the formation of curved hooks and their associated OMs, based on a careful analysis of numerous specially...

Selective laser sintering (SLS), as a kind of additive manufacturing technology, which uses beam to scan and heat powder material layer by form parts (models), is widely used in the field casting, mainly for preparing casting coated sand cores, investment patterns, etc. The SLS technique facilitates rapid shortens production periods eliminating mold preparation. In this study, we reached conclu...

Hooks and other sub-surface features in continuous-cast ultralow-carbon steel samples were examined using optical microscopy, electron backscattering diffraction, energy dispersive X-ray spectroscopy, and electron probe microanalysis techniques. Special etching reagents revealed dendrites growing from both sides of the line of hook origin. This line was found to represent the frozen meniscus an...

This study was performed to determine whether the particle size of the starting collagen powder or the material of molds used during freeze-drying had effects on the scaffold pore structure. Collagen particles were separated by size prior to slurry making using a sieve with 1000 um openings, and scaffolds were made using both metal pans and polysulfone trays, two commonly used molds. The mean a...