Overview of surface studies on high energy materials at Mound

Since 1975 Mound has been examining the surface structure of high energy materials and the interaction of these materials with various metal containers. The high energy materials that have been studied include: the pyrotechnic TiH/sub x//KClO/sub 4/, the Al/Cu/sub 2/O machinable thermite, the PETN, HMX and RDX explosives, and two plastic bonded explosives (PBX). Aluminum and alloys of Fe, Ni and Cr have been used as the containment materials. Two aims in this research are: (1) the elucidation of the mechanism of pyrotechnic ignition and (2) the compatibility of high energy materials with their surroundings. New information has been generated by coupling Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) with thermal data. In particular, AES and XPS studies on the pyrotechnic materials and on thermites have shown the mechanism of ignition to be nearly independent of the type of oxidizer present but directly related to surface chemistry of the fuels. In studies on the two PBX's, PBX-9407 and LX-16, it was concluded that the Exon coating on 9407 was complete and greater than or equal to 100A; whereas in LX-16, the coating was < 100A or even incomplete. AES and scanning Auger have been used to characterize the surface composition and oxide thickness for an iron-nickel alloy and showed the thicker oxides to have the least propensity for atmospheric hydrocarbon adsorption. Data are presented and illustrations made which highlight this new approach to studying ignition and compatibility of high energy materials. Finally, the salient features of the X-SAM-800 purchased by Mound are discussed in light of future studies on high energy materials

Pressure and Flow Properties of Cannulae for Extracorporeal Membrane Oxygenation II: Drainage (Venous) Cannulae

The use of extracorporeal life support devices such as extracorporeal membrane oxygenation in adults requires cannulation of the patient's vessels with comparatively large diameter cannulae to allow circulation of large volumes of blood (>5 L/min). The cannula diameter and length are the major determinants for extracorporeal membrane oxygenation flow. Manufacturing companies present pressure-flow charts for the cannulae; however, these tests are performed with water. Aims of this study were 1. to investigate the specified pressure-flow charts obtained when using human blood as the circulating medium and 2. to support extracorporeal membrane oxygenation providers with pressure-flow data for correct choice of the cannula to reach an optimal flow with optimal hydrodynamic performance. Eighteen extracorporeal membrane oxygenation drainage cannulae, donated by the manufacturers (n = 6), were studied in a centrifugal pump driven mock loop. Pressure-flow properties and cannula features were described. The results showed that when blood with a hematocrit of 27% was used, the drainage pressure was consistently higher for a given flow (range 10%-350%) than when water was used (data from each respective manufacturer's product information). It is concluded that the information provided by manufacturers in line with regulatory guidelines does not correspond to clinical performance and therefore may not provide the best guidance for clinicians.info:eu-repo/semantics/publishedVersio

An Auger Sputter Profiling Study of Nitrogen and Oxygen Ion Implantations in Two Titiaium Alloys

Samples of two titanium alloys, Ti-6A1-4V and Ti-15V-3Cr-3Sn-3A1, were ion implanted with a combination of nitrogen (N+) and oxygen (O+). For each alloy, implantation parameters were chosen to give implanted nitrogen concentrations of approximately 10 or 50 atomic percent, from a depth of 100 nanometers to a depth of 400 nanometers. In all but one case, dual energy (200 keV and 90 keV) implantations of nitrogen were used to give a relatively uniform nitrogen concentration to a depth of 300 nanometers. In each case, oxygen was implanted at 35 keV, following the nitrogen implantation, to give an oxygen-enriched region near the surface. The implanted samples were then examined by Auger electron spectroscopy (AES) combined with argon ion sputtering. In order to determine the stoichiometry of the nitrogen implanted regions, it was necessary to determine the N (KVV) contribution to the overlapping N (KVV) and Ti (LMM) Auger transitions. It was also necessary to correct for the ion-bombardment-induced compositional changes which have been described in an earlier study of titanium nitride thin films. The corrected AES depth profiles were in good agreement with theoretical predictions

The Dissolution of Native Oxide Films on Titanium for Pyrotechnic Applications

The dissolution of native oxides on Ti were studied over the temperature range 25 degrees - 730 degrees C to determine their role in the pyrotechnic reaction of Ti with KCl0{sub}4. From AES data it was found that the solubility of the oxide in Ti increased sharply at 350 degrees C. High resolution AES scans of the Ti LMM transitions as well as XPS scans of the Ti 2 p level showed that free Ti is present at the surface above 350 degrees C. The O 1s XPS data shows that the surface contains hydroxyl as well as oxide groups. The hydroxide to oxide ratio begins to decrease below 250 degrees C, and at 450 degrees C the remaining oxygen is bound predominatly as oxide. Additionally, the XPS data shows that the dissoluton process proceeds through the formation of titanium suboxides. These AES and XPS results complement physical property measurements which have also been made on the Ti/KCl0{sub}4 mixture. These physical property measurements show that 1) below 300 degrees C no reaction occurs and 2) just above 300 degrees C an exothermic reaction occurs corresponding to the reaction of free Ti with atmospheric oxygen

Migration for Mission: international Catholic Sisters in the United States

Patterns of migration for the purpose of religious mission are an unexamined dimension of the immigration narrative. Catholic sisters from many countries around the world come to the United States to minister and to study. Sociologists from Trinity Washington University and CARA at Georgetown University combined forces to document and understand this contemporary and historical phenomenon. Together, they located more than 4,000 international sisters who are currently in the United States for formation, studies, or ministry, from 83 countries spread over six continents. Through surveys, focus groups, and interviews, they heard the stories of these sisters and learned of their joys and satisfactions as well as their struggles and challenges.This book examines the experience of these sisters in depth and offers valuable suggestions for religious institutes, Catholic dioceses and parishes, and others who benefit from their contributions. More broadly, this book also raises awareness of immigration issues at a time of great contention in the public policy debate in the United States. Illustrated with instructive graphics and tables, it is an accessible and inviting resource for academics and the media, as well as bishops, and leaders of Catholic health care, social service, education, pastoral, and philanthropic institutions.https://repository.usfca.edu/faculty_books_all/1078/thumbnail.jp

Migration for Mission: international Catholic Sisters in the United States

Patterns of migration for the purpose of religious mission are an unexamined dimension of the immigration narrative. Catholic sisters from many countries around the world come to the United States to minister and to study. Sociologists from Trinity Washington University and CARA at Georgetown University combined forces to document and understand this contemporary and historical phenomenon. Together, they located more than 4,000 international sisters who are currently in the United States for formation, studies, or ministry, from 83 countries spread over six continents. Through surveys, focus groups, and interviews, they heard the stories of these sisters and learned of their joys and satisfactions as well as their struggles and challenges.This book examines the experience of these sisters in depth and offers valuable suggestions for religious institutes, Catholic dioceses and parishes, and others who benefit from their contributions. More broadly, this book also raises awareness of immigration issues at a time of great contention in the public policy debate in the United States. Illustrated with instructive graphics and tables, it is an accessible and inviting resource for academics and the media, as well as bishops, and leaders of Catholic health care, social service, education, pastoral, and philanthropic institutions.https://repository.usfca.edu/faculty_books_2019/1017/thumbnail.jp

Surface studies of plastic-bonded PETN and RDX by X-Ray Photoelectron Spectroscopy (XPS) and Ion-Scattering Spectroscopy (ISS)

Surface structures of plastic bonded PETN and RDX were studied by high resolution X-Ray Photoelectron Spectroscopy (XPS) and Ion Scattering Spectroscopy (ISS). The coating material is a copolymer of vinyl chloride and chlorotrifluoroethylene. Specimens with 6 wt % of the coating on RDX and 4 wt % on PETN were used in these studies. High resolution elemented XPS spectra of F 1s, N 1s, C 1s, and Cl 2p indicate that the surface of coated RDX (PBX-9407) is covered and the coating film is thicker than 100A; the results with coated PETN (LX-16) show the surface layer to be thinner than 100A. /sup 3/He/sup +/ ISS data on LX-16 suggest that the coating on PETN is not uniform and is, in fact, absent in some regions