Fatigue crack in large-scale tubular joints for offshore structures

Tubular members have been used for constructing offshore structures. Large-scale fatigue tests of welded tubular K-joints under the balanced in-plane bending brace were carried out to investigate the fatigue behavior of API 2W Gr.50 steel produced by POSCO. The experimental results were verified by numerical approaches and compared with the IIW, DnV RP-C203 and API RP 2A-WSD design curves. The test results based on the hot spot stress were in agreement with the design curves. The SCF factor for tubular K-jo...     

Highly active rhodium/carbon nanocatalysts for ethanol oxidation in alkaline medium

We report the synthesis and electrochemical characterization of rhodium/carbon (Rh/C) and palladium-rhodium/carbon (Pd-Rh/C) nanocatalysts for ethanol oxidation. Our results, for the first time, demonstrated that in an alkaline environment, Rh/C shows a much higher catalytic activity at low potential range than that of Pd-Rh/C and Pd/C. Intermediate species are produced during the oxidation process on Rh/C, as revealed by the complex impedance spectra (e.g., pseudo-inductive loop) at low potential range (i.e., −0.5 to −0.3 V). Adsorbed oxygen species, which are generated at high potentials, block active surface sites of Rh/C, resulting in the negative polarization resistance.     

Full 1H NMR assignment of a 24-nucleotide RNA hairpin: application of the 1H 3D-NOE/2QC experiment

A mixed general linear model analysis of the development of sleep-wake states was conducted on 37 high-risk preterm infants and replicated with a second cohort of 34 infants. Most dependent variables showed significant development over the preterm period: active sleep decreased, and active waking, quiet waking, and the organization of active sleep and quiet sleep increased over the preterm period in both cohorts. The amount of quiet sleep also increased over age, but this change was significant only for Cohort 1. Seven infant characteristics used as covariates had only minor effects. There were no significant differences in the developmental trajectories (slopes) of the two cohorts. The amounts of four variables differed between cohorts: Cohort 2 infants had less sleep-wake transition, more active sleep, less active sleep without REM, and more regular quiet sleep. These findings suggest that developmental patterns of sleep wake states are stable enough in the preterm period that deviant individual patterns might be used to identify infants with neurological problems.