This study was conducted to investigate whether dietary levels of copra and palm meals affect the growth performance, carcass characteristics, and meat properties of Hanwoo steers. Eighty-one Hanwoo steers were randomly assigned to one of three dietary groups: T1 (conventional level of palm and copra meals), T2 (20% copra meal and 15% palm meal), and T3 (30% copra meal and 20% palm meal). During the growing and early fattening periods, the average daily gains and formula feed intakes of T2 and T3 were higher than that of T1; however, those differences were not statistically significant. The dietary levels of copra and palm meals did not affect carcass weight, back fat thickness, and rib-eye areas. Marbling scores and meat quality grades were lower in T3 than in T1 and T2; however, those differences were not statistically significant. Meat color, fat color, texture, and maturity were similar among the treatment groups. In addition, dietary levels of copra and palm meals did not affect the chemical and fatty acid composition of longissimus dorsi muscles in Hanwoo steers. Thus, the present results indicate that high supplementation levels of copra and palm meals do not negatively affect the growth performance, carcass characteristics, and meat properties of Hanwoo steers.

This study investigated phosphorus removal from secondary treated effluent using coagulation-membrane separation hybrid treatment to satisfy strict regulation in wastewater treatment. The membrane separation process was used to remove suspended phosphorus particles after coagulation/settlement. Membrane separation with 0.2 μm pore size of micro filtration membrane could reduce phosphorus concentration to 0.02 mg P/L after coagulation with 1 mg Al/L dose of polyaluminum chloride (PACl). Regardless of coagulant, the residual concentration of phosphorus decreased as the dose increased from 1.5 to 3.5 mg Al/L, while the target concentration of 0.05 mg P/L or less was achieved at 2.5 mg Al/L for the aluminum sulfate (Alum) and 3.5 mg Al/L for PACl. Moreover, alum showed better membrane flux as make bigger particles than PACl. Alum showed a 40% of flux decrease at 2.5 mg Al/L dose, while PACl indicated a 50% decrease of membrane flux even with a higher dose of 3.5 mg Al/L. Thus, alum was more effective coagulant than PACl considering phosphorus removal and membrane flux as well as its dose. Consequently, the coagulation-membrane separation hybrid treatment could be mitigate regulation on phosphorus removal as unsettleable phosphorus particles were effectively removed by membrane after coagulation.

The use of continuous welded rail is increasing because of its many advantages, including vibration reduction, enhanced driving stability, and maintenance cost savings. In this work, two different types of continuous welded rails were examined to determine the influence of repeated wheel-rail contact on the crystal structure, microstructure and mechanical properties of the rails. The crystal structure was determined by x-ray diffraction, and the microstructure was examined using optical microscopy and scanning electron microscopy. Tensile and microhardness tests were conducted to examine the mechanical behaviors of prepared specimens taken from different positions in the cross section of both newly manufactured rail and worn rail. Analysis revealed that both the new and worn rail had a mixed microstructure consisting of ferrite and pearlite. The specimens from the top position of each rail exhibited decreased lamella spacing of the pearlite and increased yield strength, ultimate tensile strength and hardness, as compared with those from other positions of the rail. It is thought that the enhanced mechanical property on the top position of the worn rail might be explained by a mixed effect resulting from a directional microstructure, the decreased lamella spacing of pearlite, and work hardening by the repeated wheel-rail contact stress.