Diverse Processing Conditions Research Articles

A Study on the Operating Condition for Carbon-Nitrogen Removal in Wastewater and Sludge Reduction Using PVA-GEL Immobilized Microorganism

The carbon and nitrogen removal process using PVA-gel (Polyvinyl Alcohol) immobilized microorganisms was studied. The process has been operated under diverse process conditions for 12 months. The process consists of denitrification with internal recycle of 300%, nitrification, aerobic digestion reactors and settling tank. Nitrification and nitrogen removal efficiency according to gel packing ratio, temperature were studied. Yield for heterotrophs (YH), decay coefficient for heterotrophs (bH) in aerobic digestion reactor were determined to characterize the sludge reduction mechanism and compared with typical data of activated sludge process. Then SRT in aerobic digestion reactor was determined on an experimental basis and sludge reduction efficiency was calculated. The process was implemented successfully with sludge reduction efficiency of 92.0~98.5% on a basis of biomass.

Effect of phospholipid on protein structure and solubility in the extrusion of lung proteins

Bovine lung flours with residual phospholipid contents of 6·7% and 0·5% were extruded in a single-screw extruder at various temperatures and feed moistures. Disulphide bonds, followed by hydrophobic and electrostatic interactions, were the major interactions responsible for stabilization of extrudate structure. The high lipid content flour (6·7% phospholipid) presented a decrease in protein solubility after extrusion, whereas the low lipid flour (0·5% phospholipid) showed the opposite behaviour. Amino acid composition was not affected by the diverse processing conditions. Infrared spectra showed the presence of β-sheet anti-parallel structures in the extrudates even in the most drastic conditions of processing employed. Protein solubility in buffer with reducing agents plus sodium dodecyl sulphate of both extrudates was lower in the internal core than in the edges; such behaviour was not observed in a control of soya. Optical microscopy of transverse sections of lung extrudates showed a tendency of collagen to locate on their external parts. These results can be explained by the recently proposed ‘suspension model’ for biopolymer extrusion.

Mechanical properties of polypropylene/crosslinked rubber blends

AbstractMechanical properties of rubber‐modified polymers are not single‐valued functions of rubber/matrix type and rubber content, but also vary with processing conditions. The variations in mechanical properties with processing conditions arise mainly from changes in rubber‐phase dispersion. In our past work, by lightly crosslinking the rubbers to increase their melt tenacity and strength, we have succeeded in producing fine and consistent dispersions despite diverse processing conditions. In this study, mechanical properties of polypropylene/lightly crosslinked rubber blends are compared with those of polypropylene/uncrosslinked rubber blends. The results indicate that, like dispersion, mechanical properties of polypropylene/crosslinked rubber blends also appear to be consistent and independent of process variables. The influences on mechanical behavior of degree of crosslinking, rubber content, and rubber/matrix type are also discussed.

Coal gasification solid wastes: physicochemical characterization

Physicochemical and morphological characteristics of coal gasification solid wastes produced by three different processes were investigated to assess the potential environmental impacts of disposal of these wastes. The wastes were composed of either calcic or ferruginous alumino-silicate glass with small amounts (1-7%) of magnetic particles. The calcic waste had relatively clean surfaces and a homogeneous matrix composition. The magnetic fraction of the waste was composed of metallic iron particles. The ferruginous wastes were occasionally covered by iron oxide or sulfide coatings. Magnetic particles in one ferruginous waste had immiscible iron oxide and sulfide phases in a silicate matrix. The magnetic fraction of the other waste was composed of iron sulfide particles. Some chalcophile elements displayed an association with the surface coatings and magnetic fractions. The gasification solid wastes were different from each other in almost every aspect as they represent products from extremely diverse process conditions.