2,780 research outputs found
Contamination control program for the Cosmic Background Explorer: An overview
Each of the three state of the art instruments flown aboard NASA's Cosmic Background Explorer (COBE) were designed, fabricated, and integrated using unique contamination control procedures to ensure accurate characterization of the diffuse radiation in the universe. The most stringent surface level cleanliness specifications ever attempted by NASA were required by the Diffuse Infrared Background Experiment (DRIBE) which is located inside a liquid helium cooled dewar along with the Far Infrared Absolute Spectrophotometer (FIRAS). The DRIBE instrument required complex stray radiation suppression that defined a cold primary optical baffle system surface cleanliness level of 100A. The cleanliness levels of the cryogenic FIRAS instrument and the Differential Microwave Radiometer (DMR) which were positioned symmetrically around the dewar were less stringent ranging from 300 to 500A. To achieve these instrument cleanliness levels, the entire flight spacecraft was maintained at level 500A throughout each phase of development. The COBE contamination control program is described along with the difficulties experienced in maintaining the cleanliness quality of personnel and flight hardware throughout instrument assembly
Cryogenic shutter
A magnetically operated shutter mechanism is provided that will function in cryogenic or cryogenic zero gravity environments to selectively block radiation such as light from passing through a window to a target object such as a mirror or detector located inside a cryogenic container such as a dewar. The mechanism includes a shutter paddle blade that is moved by an electromagnetically actuated torquing device between an open position where the target object is exposed to ambient radiation or light and a closed position where the shutter paddle blade shields the ambient radiation or light from the target object. The purpose of the shuttering device is to prevent the mirror or other target object from being directly exposed to radiation passing through the window located on the side wall of the dewar, thereby decreasing or eliminating any temperature gradient that would occur within the target object due to exposure to the radiation. A special nylon bearing system is utilized to prevent the device from binding during operation and the paddle blade is also thermally connected to a reservoir containing cryogen to further reduce the internal temperature
Integrating Fire with Land Management Planning and Action-A Process
Adapted from a paper presented at the Joint Rocky Mountain Fire Council and Intermountain Fire Research Council Meeting, Rangeland Management and Fire, Casper, Wyoming, November 1, 2, 3, 1977
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The Effect of Driving Intensity and Incomplete Charging on the Fuel Economy of a Hymotion Prius PHEV
On-road testing was conducted on a Hymotion Prius plug-in hybrid electric vehicle (PHEV) at the Electric Transportation Engineering Corporation in Phoenix, Arizona. The tests were comprised of on-road urban and highway driving during charge-depleting and charge-sustaining operation. Determining real-world effectiveness of PHEVs at reducing petroleum consumption in real world driving was the main focus of the study. Throughout testing, several factors that affect fuel consumption of PHEVs were identified. This report discusses two of these factors: driving intensity (i.e., driving aggressiveness) and battery charging completeness. These two factors are unrelated, yet both significantly impact the vehicle’s fuel economy. Driving intensity was shown to decrease fuel economy by up to half. Charging completeness, which was affected by human factors and ambient temperature conditions, also showed to have great impact on fuel economy for the Hymotion Prius. These tests were performed for the U.S. Department of Energy’s Advanced Vehicle Testing Activity. The Advanced Vehicle Testing Activity, part of the U.S. Department of Energy’s Vehicle Technology Program, is conducted by the Idaho National Laboratory and the Electric Transportation Engineering Corporation
Spectral statistics of a minimal quantum glass model
Glasses have the interesting feature of being neither integrable nor fully
chaotic. They thermalize quickly within a subspace but thermalize much more
slowly across the full space due to high free energy barriers which partition
the configuration space into sectors. Past works have examined the
Rosenzweig-Porter (RP) model as a minimal quantum model which transitions from
localized to chaotic behavior. In this work we generalize the RP model in such
a way that it becomes a minimal model which transitions from glassy to chaotic
behavior, which we term the "Block Rosenzweig-Porter" (BRP) model. We calculate
the spectral form factors of both models at all timescales. Whereas the RP
model exhibits a crossover from localized to ergodic behavior at the Thouless
timescale, the new BRP model instead crosses over from glassy to fully chaotic
behavior, as seen by a change in the slope of the ramp of the spectral form
factor.Comment: 41 pages, 10 figure
An Analysis of the Long-Term Salinity Patterns in the Louisiana Coastal Zone
Saltwater intrusion is believed to be one of the greatest threats to Louisiana\u27s fishery and wildlife resources. The Louisiana Department of Wildlife and Fisheries has maintained salinity recording stations throughout the state\u27s coastal marshes since the 1960\u27s. We applied several different analytical approaches to the salinity data from 17 stations to determine whether this data base could be used to detect and quantity long-term salinity trends in coastal Louisiana.
We did not detect a large-scale, consistent trend over time in coastal salinities across the state. Problems that hindered the detection of long-term trends included short periods of record and the placement of the recording stations in salt and brackish marsh areas, where we would not expect to find great changes in salinity. For the data to be useful in monitoring salinity trends in coastal marshes, especially with respect to saltwater intrusion, stations should be added in fresh and intermediate marshes. In addition, the relationships our study revealed between short- and long-term data indicate that records covering less than a decade are insufficient to denote long-term salinity changes, barring some major modification of the hydrologic regime
Results from the Operational Testing of the General Electric Smart Grid Capable Electric Vehicle Supply Equipment (EVSE)
The Idaho National Laboratory conducted testing and analysis of the General Electric (GE) smart grid capable electric vehicle supply equipment (EVSE), which was a deliverable from GE for the U.S. Department of Energy FOA-554. The Idaho National Laboratory has extensive knowledge and experience in testing advanced conductive and wireless charging systems though INL’s support of the U.S. Department of Energy’s Advanced Vehicle Testing Activity. This document details the findings from the EVSE operational testing conducted at the Idaho National Laboratory on the GE smart grid capable EVSE. The testing conducted on the EVSE included energy efficiency testing, SAE J1772 functionality testing, abnormal conditions testing, and charging of a plug-in vehicle
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