Wright-Patterson Air Force Base

About: Wright-Patterson Air Force Base is a other organization based out in Wright-Patterson AFB, Ohio, United States. It is known for research contribution in the topics: Laser & Mach number. The organization has 5817 authors who have published 9157 publications receiving 292559 citations. The organization is also known as: Wright-Patterson AFB & FFO.

Nonstoichiometry of ZrO2 and Its Relation to Tetragonal‐Cubic Inversion in ZrO2

Abstract: The system Zr-O was studied in the composition range 50 to 66.7 at.% O by metallographic analysis, high-temperature X-ray analysis, and lattice parameter determinations at room temperature. The solubility of zirconium in zirconia was determined from 1200° to 2000°C, and the cubic-tetragonal inversion temperature of ZrO2 was shown to be lowered to approximately 1490°C for samples containing α-Zr and oxide phase. Alpha zirconium has greater solubility in the cubic phase than in the tetragonal phase, and the inversion is revealed, in samples quenched from the cubic field, by the exsolution of α-Zr, which is metallographically characterized as striations. At room temperature, the striations are oriented with the 111 and 11° planes of monoclinic zirconia.

Cholecystectomy during pregnancy without fetal loss.

Abstract: Cholecystectomy in the pregnant patient has been generally avoided because of the reported high incidence of associated fetal loss that has been linked to spontaneous and elective abortion during the first trimester and premature labor during the third trimester. Recent developments relating to diagnostic and anesthetic management and the use of tocolytic agents have altered the over-all approach to patients. We have, therefore, retrospectively reviewed the medical records of all women discharged from four area hospitals during 1982 to 1987 with a concurrent diagnosis of cholelithiasis and pregnancy. Twenty-two patients met the review criteria. The incidence of biliary stone disease among gravid patients during the time interval was 0.05 per cent. Of 22 patients, none underwent radiation for diagnosis. Nine patients underwent cholecystectomy while pregnant; two were operated upon during the first trimester, four during the second and three during the third. Three required common bile duct exploration and three had intraoperative cholangiograms. Elective abortion was not recommended to the six patients because of radiation exposure. Two of nine had premature contractions develop that were controlled with tocolytic agents. There were no spontaneous abortions. The mean Apgar scores for neonates born subsequent to cholecystectomy was virtually identical to neonates born to patients in whom cholecystectomy was deferred. It is concluded that the diagnosis and surgical treatment of cholelithiasis can be safely undertaken in the pregnant patient without fetal loss. Delaying appropriate surgical therapy no longer seems warranted.

Lubricants: Super slippery solids

Abstract: Most lubricants are liquids, but beyond the liquid realm - at high or low temperature, or in a vacuum - solid lubricants are needed. Conventional solid lubricants are also limited in their range of operation, but a new generation of solid lubricants may be with us. Hollow nanoparticles of tungsten sulphide (similar to carbon fullerenes and nanotubes) have now been synthesized, and they are more slippery and more robust than other materials. Instead of slipping between weakly bonded crystal planes, these nanoparticles may lubricate by rolling.

Strength of discontinuous reinforced composites: I. Fiber reinforced composites

Abstract: The strength of randomly oriented short fiber composites has been modeled by a quasi-isotropic laminate. Lamination theory and a failure criterion will be used to approximate the stress-strain response of a composite as it is loaded to failure. Experimental data are presented and compared with the maximum-strain failure criterion.