Ignition of metals in high pressure oxygen

A description of an experimental facility used to determine the ignition and combustion characteristics of metallic materials is given. The results obtained for aluminum 6061, 302 stainless steel, and the nickel alloy - N06625 are presented

Laser-initiated combustion studies of selected aluminum, copper, iron, and nickel alloys

The results of combustion studies at atmospheric pressure on ten metal alloys are presented. The alloys studied were aluminum alloys 1100, 2219, 6061, and tensile-50; 304, 347 and 21-6-9 stainless steel; inconel 600; beryllium copper and a bronze. It was found that once ignition was achieved all alloys would generally burn to completion. The overall combustion process appears to obey a first order rate process. Preliminary conclusions are presented along with recommendations for future work

Ignition characteristics of the nickel-based alloy UNS N07001 in pressurized oxygen

The development of ignition and combustion in pressurized oxygen atmospheres was studied for the nickel-based alloy UNS N07001. Ignition of the alloy was achieved by heating the top surface of a cylindrical specimen with a continuous-wave CO2 laser. Two heating procedures were used. In the first, laser power was adjusted to maintain an approximately linear increase in surface temperature. In the second, laser power was periodically increased until autoheating (self-heating) was established. It was found that the alloy would autoheat to combustion from temperatures below the solidus temperature. In addition, the alloy had a tendency to develop combustion zones (hot spots) at high oxygen pressures when the incremental (step) heating test mode was used. Unique points on the temperature-time curves that describe certain events are defined and the temperatures at which these events occur are given for the oxygen pressure range of 1.72 to 13.8 MPa (250 to 2000 psia)

Flammability study of materials in oxygen environments

Report presents flame-propagation rates and flammability ratings of 780 specimens of commercially available plastics, elastomers, coatings, fabrics, and other sheet materials. Test results are also given for over 1970 samples of most commonly used electrical harnesses, connectors, and potting compounds

Star formation in collisional ring galaxies and the circumnuclear regions of active galactic nuclei

This dissertation contains multiwavelength observational projects on collisional ring galaxies, active galactic nuclei (AGNs), and neutral hydrogen observations of the collisional ring galaxy Arp 118 (an interacting pair NGC 1144/1143);I have demonstrated in my dissertation research that: starburst knots of individual collisional ring galaxies cluster around the same, very young age suggesting that their formation was recently triggered by a coherent event all around the ring and strongly supports their production as a result of the passage of a radial density wave; the atomic and molecular emission in the strongly interacting galaxy Arp 118 appears to be very asymmetrically distributed such that the NW region of the galaxy is mainly atomic hydrogen, whereas the SE region has an interstellar medium which is ~94% molecular hydrogen. One possibility is that in the SE region there is a rapid conversion of HI to H2, which may be a result of the highly off-center collision between NGC 1144 and NGC 1143; and the global far-infrared colors of Seyfert galaxies may be linked to their radio morphologies

The Use of Critical Ethnography in Managed Mental Health Care Settings

How social workers in managed mental health care settings exercise their professional authority may have profound consequences for the provision of ethical and value-based services to vulnerable populations. Building upon Gidden\u27s theory of structuration, this article describes the use of critical ethnography as a specific research methodology that may support social workers in the exercise of their authority. This article examines the historical roots of critical ethnography and provides a detailed examination of its underlying assumptions and research procedures. The article concludes with a case example of a critical ethnography conducted within a managed mental health care setting

An Examination of Factors Affecting Information Sharing among Law Enforcement Agencies

The purpose of the present study was to investigate using survey data to find factors or barriers which contributed to local law enforcement participation and support of intelligence information sharing. Following the September 11, 2001, attacks in New York City and Arlington, Virginia, new homeland security initiatives and directives were created from the legislative and executive branches of the federal government. Several new initiatives and directives provided new communication opportunities for partnerships between all levels of law enforcement to combat the future threat of domestic terrorism. The evaluation literature indicated that a majority of post-9/11, initiatives, including the creation of the Department of Homeland Security, were strategically implemented using a top-down, reactive approach to terrorism-related intelligence gathering. Technological, organizational, or cultural breakdowns between the federated jurisdictions of law enforcement contributed to the vulnerability of United States defense capabilities. Disparate pieces of intelligence information were available to several federal, state, and local terror investigation agencies, but the agencies were not able to piece together the information in a timely manner. The study examined implementation issues from a bottom-up perspective with participant local law enforcement departments in four separate states, across four geographic areas of the country. In order to examine these issues, responses of participants in the study were analyzed through the administration of a survey instrument. Participants also were provided an optional opportunity to provide qualitative data on the last page of the survey instrument. One of the goals of the study was to identify barriers so a more proactive approach with more partnerships can be implemented through the development of a seamless communicative network where terror information can be shared interoperable across all levels of law enforcement