640 research outputs found
Space Weather Monitoring for ISS Space Environments Engineering and Crew Auroral Observations
The awareness of potentially significant impacts of space weather on spaceand ground ]based technological systems has generated a strong desire in many sectors of government and industry to effectively transform knowledge and understanding of the variable space environment into useful tools and applications for use by those entities responsible for systems that may be vulnerable to space weather impacts. Essentially, effectively transitioning science knowledge to useful applications relevant to space weather has become important. This talk will present proven methodologies that have been demonstrated to be effective, and how in the current environment those can be applied to space weather transition efforts
Chemical Characterization and Thermal Stressing Studies of Perfluorohexane Fluids for Space-Based Applications
Perfluorohexane (PFH), C6F14, is a perfluorocarbon fluid. Several PFH fluids with different isomer concentrations were evaluated for use in an upcoming NASA space experiment. Samples tested included two commercially obtained high-purity n-perfluorohexane (n-PFH) fluids and a technical grade mixture of C6F14 branched and linear isomers (FC-72(TradeMark)). These fluids were evaluated for exact chemical composition, impurity purity and high temperature degradation behavior (pyrolysis). Our investigation involved simulated thermal stressing studies of PFH fluids under conditions likely to occur in the event of an atmospheric breach within the International Space Station (ISS) and subsequent exposure of the vapors to the high temperature and catalyst present in its Trace Contaminant Control Subsystem (TCCS). Exposure to temperatures in the temperature range of 200-450 C in an inert or oxidizing atmosphere, with and without the presence of catalyst was investigated. The most aggressive conditions studied were exposure of PFH vapors to 450 C in air and in the presence of TCCS (palladium) catalyst. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography (GC) analyses were conducted on the perfluorohexane samples before and after pyrolysis. The FC-72 and n-PFH samples showed no significant degradation following pyrolysis even under the most aggressive study conditions. Some trace level impurities associated with the PFH samples such as linear perfluorocarbon monohydrides or monoiodides were destroyed by pyrolysis at the upper limit. Other trace level impurities such as olefinic or cycloolefinic perfluorocarbons were converted into oxidation products by pyrolysis. The purity of PFH following pyrolysis actually increased slightly as a consequence since these trace contaminants were effectively scrubbed from the samples. However, since the initial concentrations of the thermally-impacted impurities were so low, the net effect was trivial. A potential byproduct of exposure of perfluorohexane fluids to high temperatures is the production of perfluoroisobutene (PFiB), which is extremely toxic. An ultra-high sensitivity PFiB-specific analysis based on GC-MS with negative ion chemical ionization (NICI) detection was used to evaluate the samples following thermal stressing. The perfluorohexanes examined here under conditions reflective of the ISS TCCS environment showed no signs of PFiB production with an analytical detection limit of 10 part per billion (ppb v/v)
International Space Station Columbus Payload SoLACES Degradation Assessment
SOLAR is a European Space Agency (ESA) payload deployed on the International Space Station (ISS) and located on the Columbus Laboratory. It is located on the Columbus External Payload Facility in a zenith location. The objective of the SOLAR payload is to study the Sun. The SOLAR payload consists of three instruments that allow for measurement of virtually the entire electromagnetic spectrum (17 nm to 2900 nm). The three payload instruments are SOVIM (SOlar Variable and Irradiance Monitor), SOLSPEC (SOLar SPECctral Irradiance measurements), and SolACES (SOLar AutoCalibrating Extreme UV/UV Spectrophotometers)
Prospectus, August 30, 1978
WELCOME BACK; Parkland prepares for fall \u2778 semester; Charter member named; Classical vocal choral group begins season; \u27Darrow\u27 stars at PC; Aid for women; WPCD\u27s Top 15 For The Week Of August 28!!!; Enrollment-- A record-breaking year, foreign students join PC; Pres. Staerkel greets students; Dean of students extends welcome; Survival: win the game; 1978-79 PC student government elections Sept. 13 and 14th; PC Communications Division sponsors St. Louis field trip; Low back pain to be discussed; 3 new PC courses; Season tickets now available; Free Classifieds; Coach impresses camp; Campus trainer is honored; Cobras leave mark in \u2777-\u2778 record books; Promising seasonhttps://spark.parkland.edu/prospectus_1978/1014/thumbnail.jp
Engineering Animation: A Corporate Case Study
The use of engineering and architectural CAD models in 3D animation an simulation is rapidly becoming a widespread activity in American business and industry. Paralleling this, the ease of interchanging digital and video formats allows engineers and architects the opportunity to merge proposed 3D digital designs directly with existing conditions captured on video. Commercial application of this process impacts areas ranging from preliminary design and analysis through marketing and training. The primary objective of this article is to provide a first-hand account of a corporate project in which 3D engineering models and construction data were used as a basis for producing an engineering marketing animation for the Caterpillar Corporation. The secondary objective of this paper is to describe the role of graphics students involved in this project. The article includes an overview of how CAD models furnished by Caterpillar were used in the production process
Technical Challenges Associated with In-Air Wingtip Docking of Aircraft in Forward Flight
Autonomous in-air wingtip docking of aircraft offers significant opportunity for system level performance gains for numerous aircraft applications. Several of the technical challenges facing wingtip docking of fixed-wing aircraft are addressed in this paper, including: close proximity aerodynamic coupling; mechanisms and operations for robust docking; and relative state estimation methods. A simulation framework considering the aerodynamics, rigid-body dynamics, and vehicle controls is developed and used to perform docking sensitivity studies for a system of two 5.5% scale NASA Generic Transport Model aircraft. Additionally, proof of- concept testing of a candidate docking mechanism designed to move the primary wingtip vortex inboard suggests the viability of such an approach for achieving robust docking
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Blast mitigation capabilities of aqueous foam.
A series of tests involving detonation of high explosive blanketed by aqueous foam (conducted from 1982 to 1984) are described in primarily terms of recorded peak pressure, positive phase specific impulse, and time of arrival. The investigation showed that optimal blast mitigation occurs for foams with an expansion ratio of about 60:1. Simple analyses representing the foam as a shocked single phase mixture are presented and shown inadequate. The experimental data demonstrate that foam slows down and broadens the propagated pressure disturbance relative to a shock in air. Shaped charges and flyer plates were evaluated for operation in foam and appreciable degradation was observed for the flyer plates due to drag created by the foam
Impact of historical land‐use changes on greenhouse gas exchange in the U.S. Great Plains, 1883–2003
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117205/1/eap20112141105.pd
Submitting Plant Specimens for Disease Diagnosis
Accurate diagnosis of a plant disease depends on having a fresh sample representative of the problem. To get an accurate diagnosis when your plant has a disease problem, you need to collect the right kind of sample.
You also need to provide complete information about the plant and its history. Since the county Extension agent and the person making a diagnosis probably won\u27t see the problem first hand at the growing site, you need to help them create a mental picture of the disease situation. You can provide this help by filling out the information requested on various Plant Disease Diagnostic Lab forms, along with the sample. Complete information and a representative sample are keys to an accurate diagnosis.
Before you collect the sample, please find the part of this publication relating to your plant\u27s problem and read it carefully. Doing so can save you a lot of wasted time and effort and will help you get an accurate diagnosis
International Space Station Spacecraft Charging Environments: Modeling, Measurement and Implications for Future Human Space Flight Programs
Spacecraft charging analysis and migration is an interdisciplinary subject combining aspects of electrostatics, plasma physics, ionizing radiation, and materials science, as well as electronic system electromagnetic interference and compatibility (EMI/EMC) effects. Spacecraft charging hazards are caused by the accumulation of electrical charge on spacecraft and spacecraft components produced by interactions with space plasmas, energetic charged particles, and solar UV photons as well as spacecraft electrical power and propulsion systems operations. Spacecraft charging hazard effects include both hard and soft avionics and electrical power system anomalies and have led to the partial or complete loss of numerous spacecraft. The International Space Station (ISS) orbital altitude and inclination (~400 km and 51.6o) determined the dominant natural environment factors affecting ISS spacecraft charging; high speed flight through the geomagnetic field and electrical power system interaction with the cold, high-density ionospheric plasma. In addition ISS is exposed to energetic auroral electrons at high latitude. In this paper we present the results of ISS spacecraft charging modeling and measurements and compare the measurements with numerical modeling of ISS charging processes. ISS is a large metallic structure and flight through the geomagnetic field at orbital speed dominates ISS charging. Collection of ionospheric electrons by the large 160V PV arrays is the next largest contributor. Charging by auroral electrons is detectable but makes a relatively minor contribution. Finally we report the observation of short duration (~ 1 sec) rapid charging peaks associated with shunt/un-shunt operations of the 160V PV arrays, a phenomena not predicted before flight. ISS spacecraft charging environments are radically different from those encountered at higher altitudes in Earth?s magnetosphere and in cis-Lunar space. We present a brief review of those charging environments and an assessment of the applicability of ISS spacecraft charging management and experience to future human spaceflight programs beyond LEO
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