Addition of silicon improves oxidation resistance of nickel based superalloys

Specific weight changes of nickel-base superalloy B-1900 and B-1900 + 1% Si specimens were tested at 1273 K. B-1900 was losing weight at an increasing rate due to spalling of oxide scale while B-1900 + 1% Si was still gaining weight at low, nearly constant rate. Similar comparison in weight change was observed for specimens tested at 1373 K

Effects of silicon additions on oxidation and mechanical behavior of the nickel-base superalloy B-1900

Test specimens with nominal additions of Si were tested in oxidation, thermal fatigue, sulfidation, tension, and stress rupture, and were also extensively studied metallographically. Alloy B-1900 modified with 0.6- or 1.2-wt% Si exhibited oxidation resistance equivalent to that of aluminide-coated B-1900 during cyclic, high-gas-velocity oxidation tests. Resistances to thermal fatigue and sulfidation were improved by the Si additions, but were not superior to aluminide-coated B-1900. Stress-rupture tests at 1000 C of specimens given the standard heat treatment to simulate an aluminide coating cycle showed Si to be detrimental. However, application of another heat treatment increased the rupture life of the alloy with 0.6-wt% Si to that of the unmodified B-1900 given the standard heat treatment

Charged Particle Motion in a Highly Ionized Plasma

A recently introduced method utilizing dimensional continuation is employed to compute the energy loss rate for a non-relativistic particle moving through a highly ionized plasma. No restriction is made on the charge, mass, or speed of this particle. It is, however, assumed that the plasma is not strongly coupled in the sense that the dimensionless plasma coupling parameter g=e^2\kappa_D/ 4\pi T is small, where \kappa_D is the Debye wave number of the plasma. To leading and next-to-leading order in this coupling, dE/dx is of the generic form g^2 \ln[C g^2]. The precise numerical coefficient out in front of the logarithm is well known. We compute the constant C under the logarithm exactly for arbitrary particle speeds. Our exact results differ from approximations given in the literature. The differences are in the range of 20% for cases relevant to inertial confinement fusion experiments. The same method is also employed to compute the rate of momentum loss for a projectile moving in a plasma, and the rate at which two plasmas at different temperatures come into thermal equilibrium. Again these calculations are done precisely to the order given above. The loss rates of energy and momentum uniquely define a Fokker-Planck equation that describes particle motion in the plasma. The coefficients determined in this way are thus well-defined, contain no arbitrary parameters or cutoffs, and are accurate to the order described. This Fokker-Planck equation describes the longitudinal straggling and the transverse diffusion of a beam of particles. It should be emphasized that our work does not involve a model, but rather it is a precisely defined evaluation of the leading terms in a well-defined perturbation theory.Comment: Comments: Published in Phys. Rep. 410/4 (2005) 237; RevTeX, 111 Pages, 17 Figures; Transcription error corrected in temperature equilibration rate (3.61) and (12.44) which replaces \gamma-2 by \gamma-

Cross Contamination in Levered Endoscopes

Contamination is a prevalent issue with reprocessed levered endoscopes. The number of infections caused by resistant enterobacteriaceae in patients due to contaminated endoscopes increased to the point that the United States Food and Drug Administration released a safety alert to health care facilities that perform endoscopic retrograde cholangiopancreatography (ERCP). The purpose of this descriptive project was to evaluate if levered endoscopes used in ERCP procedures met high level disinfection criteria, were properly processed, and were germ free after reprocessing. The project was supported by 2 theories: the middle range theory of patient advocacy and the germ theory. Data (counts and percentages) were collected from testing 150 endoscopes at each of 4 facilities within an organization regarding the effectiveness of the reprocessing of the levered endoscopes. According to the project findings, there was a 7% average germ-free failure rate across the sites after the initial reprocessing. The cleaning process of the levered endoscopes allowed bacteria to remain on the scopes after the manufacturer-recommended cleaning was completed at the sites. Standardization of the organization\u27s cleaning process and improvement in the national protocols were recommended. The project supported protecting the safety of endoscopy patients by identifying that the cleaning process could be improved to prevent introduction of infectious bacteria through a procedure. The results will be informative for laboratory staff who clean levered endoscopes, physicians who use the scopes in patient procedures, patients who undergo the procedures, and nurses who are tasked with improving patient safety in perioperative environments

The Concordiensis, Volume 3, Number 1

Literary: Only Second-Handed? (Poetry); Music; The Jews and their History; A Mother\u27s Message Editorial: Salutatory; College Sports; A Word to the Wise; Departure of Dr. Lowell; The Senior Class with Dr. Darling; The Annual Cane Rush; Election of Officers-of the Senior Class; A Mystery Solved; The Adelphic Society; The Idol; The Rush Local: Local Briefs; Chronicles of the Cane Rush; College Singing Exchanges; Personals; Extraneahttps://digitalworks.union.edu/concordiensis_1879/1005/thumbnail.jp