William M. Chirdon

Mechanical and thermal characterization of carbon nanofiber reinforced low-density polyethylene composites:

The mechanical, thermal, and fracture morphological characterization of low-density polyethylene (LDPE) composites reinforced with vapor-grown carbon nanofibers (VGCNFs) is presented in this article. VGCNF/LDPE composites with different VGCNF weight percentages were prepared by single-screw extrusion followed by injection molding. Scanning electron microscopy showed that VGCNFs were predominantly dispersed uniformly within the LDPE matrix. Differential scanning calorimetry has shown that the VGCNF/LDPE composites crystallized at higher temperatures than pure LDPE polymer. Tensile testing has shown that strength and Young’s modulus of VGCNF/LDPE composites were improved by 15% and 44%, respectively, when the VGCNF loading reached 3 wt%.

Mechanisms of goniochromism relevant to restorative dentistry

OBJECTIVES This study aims to determine the effects of multiple translucent layers, the alignment of composite structures, and specular reflecting backings as goniochromatic mechanisms relevant to dentistry. METHODS Rectangular composite specimens were filled with very short E-glass fibers (120 microm length, 16 microm diameter). The fibers were oriented random, perpendicular, and parallel to the surface normal using an electric field. A Minolta CS-100 colorimeter was used to measure the color at various angles of samples with various filler alignments, translucent sublayers, and specular reflecting backings. RESULTS All three investigated mechanisms were proven to have a goniochromatic effect. Filler alignment perpendicular to the surface made the composites more transmissive and reduced the dependence of lightness on observation angle. Backing composites with a pigmented sublayer caused the color of the sublayer to be more apparent when the observation angle is perpendicular to the surface. The specular reflection of a gold backing was only partially diffused by the specimen. SIGNIFICANCE The determination of the effects of these goniochromatic mechanisms is relevant to dentistry, because teeth are naturally aligned composites composed of multiple translucent layers. Therefore, understanding these goniochromatic effects is important to recreating them in restorative materials. Also, gold backings were previously found to give restoratives a more vital appearance, and this perceived vitality may be related to goniochromism.

Utilization of Biorefinery Waste Proteins as Feed, Glues, Composites, and Other Co-Products

In recent decades, there have been significant advances in bioprocessing technologies which have brought large-scale algal biorefineries closer to becoming environmentally and economically sustainable. Yet, due to the costs of algae culture and lipid extraction, it is difficult to design a profitable biorefinery operation, especially if the only valuable products produced are biofuels. Biorefineries typically generate large volumes of solid, proteinaceous biomass with little or no value. These residues are often referred to as algae cake or post-extracted algal residue (PEAR). If a company needs to pay to dispose of these byproducts, it will be nearly impossible to operate profitably.