The physics and chemistry of dusty plasmas: A laboratory and theoretical investigation

Theoretical work on dusty plasmas was conducted in three areas: collective effects in a dusty plasma, the role of dusty plasmas in cometary atmospheres, and the role of dusty plasmas in planetary atmospheres (particularly in the ring systems of the giant planets). Laboratory investigations consisted of studies of dust/plasma interactions and stimulated molecular excitation and infrared emission by charged dust grains. Also included is a list of current publications

Method and apparatus for determining satellite orientation utilizing spatial energy sources Patent

Sensing method and device for determining orientation of space vehicle or satellite by using particle trap

Active experiments in modifying spacecraft potential: Results from ATS-5 and ATS-6

The processing of data from onboard spacecraft instruments are described. The modification of spacecraft potentials is reviewed. Analysis of this data yielded the following results: (1) electron emission (E approximately 10 electron-volts) did not perturb the status of a satellite at low potential the absolute value of phi approximately 50 volts by more than 50 volts (the ATS 5 low energy limit), (2) emission of a low energy plasma (E approximatey 10 volts) does not change low potentials (the absolute value of phi approximately 5 volts) by more than a few volts (ATS 6 low energy resolution), (3) when ATS 6 entered eclipse in the presence of a high energy plasma (10 keV), the neutralizer suppressed any rise in the absolute value of phi (within a few volts resolution), (4) when the electron emitter on ATS 5 operated, it served to discharge negative potentials from thousands to hundreds of volts, and (5) when the neutralizer on ATS 6 was operated, it served to discharge kilovolt potentials to below 50 volts. Low altitude (100 - 300 km) experiments with KV electron beams are studied. Differential charging was eliminated by the operation of the main thruster on ATS 6 clamped on the spacecraft at -5 volts

Impact ionization study

The impact ionization phenomenon which was observed on certain spacecraft was studied. The phenomenon occurs when a neutral atom, molecule, or ion strikes a surface with sufficient kinetic energy that either the incident neutral or atoms on the surface are ionized, with subsequent escape of ions and/or electrons. The released ions and electrons can interfere with measurements on the spacecraft by confusing interpretation of the data. On the other hand, there is the possibility that the effect could be developed into a diagnostic tool for investigating neutral atmospheric species or for studying physical processes on spacecraft surfaces

The problem of low energy particle measurements in the magnetosphere

The accurate measurement of low energy (less than 100 eV) particle properties in the magnetosphere has been difficult, partly because of the low density of such particles, but more particularly because of spacecraft interference effects. Some early examples of how these phenomena have affected particle measurements on an OGO spacecraft are presented. Data obtained with the UCSD particle detectors on ATS-6 are then presented showing how some of these difficulties have been partially overcome. Future measurements of low energy particles in the magnetosphere can be improved by: (1) improving the low energy resolution of detectors; (2) building electrostatically clean spacecraft; (3) controlling spacecraft potential; and (4) using auxiliary measurements, particularly wave data

The utilization of an infrared imaging system as a cooling slot blockage detector in the inspection of a transpiration cooled nozzle

A comprehensive examination of the 8 foot temperature tunnel's transpiration cooled nozzle was completed using an infrared imaging radiometer to locate regions of cooling flow irregularities caused by obstruction of three or more adjacent cooling slots. Restrictions in the cooling flow were found and cataloged. Blockages found were due primarily to the presence of residual phosphoric acid being discharged from some of the cooling slots. This acid was used during construction of the nozzle components and was to have been purged prior to its delivery to the NASA Langley Research Center (LaRC). In addition, a radial displacement of one selection of discs located in the spool piece was inspected and cataloged for future reference. There did not seem to be a serious restriction of flow in this defect, but evidence from the infrared images indicated reduced slot activity within the gouge. The radiometer survey uncovered regions where closer inspection is recommended but did not cover the entire surface area of the three nozzle subsections due to equipment limitations. A list of areas with suspected problems is included in Appendix A

Proceedings of the Spacecraft Charging Technology Conference: Executive Summary

Aerospace environments are reviewed in reference to spacecraft charging. Modelling, a theoretical scheme which can be used to describe the structure of the sheath around the spacecraft and to calculate the charging currents within, is discussed. Materials characterization is considered for experimental determination of the behavior of typical spacecraft materials when exposed to simulated geomagnetic substorm conditions. Materials development is also examined for controlling and minimizing spacecraft charging or at least for distributing the charge in an equipotential manner, using electrical conductive surfaces for materials exposed to space environment

Linking Health Information Technology to Patient Safety and Quality Outcomes: A Bibliometric Analysis and Review

Informatics for Health and Social Care is published by Informa Healthcare. Publisher's version can be found at: http://informahealthcare.com/doi/abs/10.3109/17538157.2012.678451OBJECTIVE: To assess the scholarly output of grants funded by the Agency for Healthcare Research and Quality (AHRQ) that published knowledge relevant to the impact of health information technologies on patient safety and quality of care outcomes. STUDY DESIGN: We performed a bibliometric analysis of the identified scholarly articles, their journals, and citations. In addition, we performed a qualitative review of the full-text articles and grant documents. DATA COLLECTION/EXTRACTION METHODS: Papers published by AHRQ-funded investigators were retrieved from MEDLINE, journal impact factors were extracted from the 2010 Thompson Reuters Journal Citation Report, citations were retrieved from ISI's Web of Knowledge and Google Scholar. PRINCIPAL FINDINGS: Seventy-two articles met the criteria for review. Most articles addressed one or more of AHRQ's outcome goals and focus priorities. The average impact factor for the journals was 4.005 (range: 0.654-28.899). The articles, and their respective grants, represented a broad range of health information technologies. CONCLUSIONS: This set of AHRQ-funded research projects addressed the goals and priorities of AHRQ, indicating notable contributions to the scientific knowledge base on the impact of information system use in healthcare.This work was supported, in part, by the National Resource Center of the Agency for Healthcare Research and Quality, contract number 290-04-0016

Evaluation of tantalum for mercury containment in the SNAP-8 boiler

Corrosion testing of tantalum for mercury containment in SNAP 8 boile