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At least 559 records · Page 31

Integrated analysis tools for trade studies of spacecraft controller and sensor locations

The present investigation was conducted with the aim to evaluate the practicality and difficulties of modern control design methods for large space structure controls. The evaluation is used as a basis for the identification of useful computer-based analysis tools which would provide insight into control characteristics of a spacecraft concept. A description is presented of the wrap-rib antenna and its packaging concept. Attention is given to active control requirements, a mathematical model of structural dynamics, aspects of sensor and actuator location, the analysis approach, controllability, observability, the concept of balanced realization, transmission zeros, singular value plots, analysis results, model reduction, and an interactive computer program. It is pointed out that the application of selected control analysis tools to the wrap-rib antenna demonstrates several capabilities which can be useful during conceptual design.

Rowell, L. F.↗

Metadata Authoring with Versatility and Extensibility

NASA's Global Change Master Directory (GCMD) assists the scientific community in the discovery of and linkage to Earth science data sets and related services. The GCMD holds over 13,800 data set descriptions in Directory Interchange Format (DIF) and 700 data service descriptions in Service Entry Resource Format (SERF), encompassing the disciplines of geology, hydrology, oceanography, meteorology, and ecology. Data descriptions also contain geographic coverage information and direct links to the data, thus allowing researchers to discover data pertaining to a geographic location of interest, then quickly acquire those data. The GCMD strives to be the preferred data locator for world-wide directory-level metadata. In this vein, scientists and data providers must have access to intuitive and efficient metadata authoring tools. Existing GCMD tools are attracting widespread usage; however, a need for tools that are portable, customizable and versatile still exists. With tool usage directly influencing metadata population, it has become apparent that new tools are needed to fill these voids. As a result, the GCMD has released a new authoring tool allowing for both web-based and stand-alone authoring of descriptions. Furthermore, this tool incorporates the ability to plug-and-play the metadata format of choice, offering users options of DIF, SERF, FGDC, ISO or any other defined standard. Allowing data holders to work with their preferred format, as well as an option of a stand-alone application or web-based environment, docBUlLDER will assist the scientific community in efficiently creating quality data and services metadata.

Pollack, Janine↗

AmeriFlux FLUXNET-1F US-KFS Kansas Field Station

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-KFS Kansas Field Station. This is the FLUXNET version of the carbon flux data for the site US-KFS Kansas Field Station produced by applying the standard ONEFlux (1F) software. Site Description - The study is an abandoned grassland at the Kansas Field Station and Ecological Reserves. The site is located within the tallgrass prairie-deciduous forest ecotonal area. The site was subjected to intensive agriculture from the 1940s through the late 1960s. In the mid-1970s, the site was planted with the cool-season grass Bromus inermis and used as a hay meadow until 1987. Then, mowing and burning approximately every five years maintained it as a grassland until 2007, when the eddy flux tower was installed.

Brunsell, Nathaniel↗

AmeriFlux AR-Bal Balcarce BA

This is the AmeriFlux version of the carbon flux data for the site AR-Bal Balcarce BA. Site Description - The study was carried out in a 19-ha rainfed soybean plot at the Unidad Integrada Balcarce, located southeast of Buenos Aires, Argentina. The site is located in an environment of gentle hills at 130 m.a.s.l. Its soil was classified as a typical Argiudoll, with a loamy clayey texture up to 0.30 m and between 0.80 to 1.10 m depth, and a clayey texture between 0.30 and 0.80 m depth. The slope was 1:50 and oriented NE to SW. A caliche layer was found at 1 to 1.2 m depth thus the water table was considered beneath that level. The soybean variety used was DM 3810, Maturity Group III with an indeterminate growing habit. It was sown on November 21, 2012, and emerged on December 1. The crop archive had a maximum height of 0.75 m.

Gassmann, Maria Isabel↗

AmeriFlux FLUXNET-1F AR-Bal Balcarce BA

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site AR-Bal Balcarce BA. This is the FLUXNET version of the carbon flux data for the site AR-Bal Balcarce BA produced by applying the standard ONEFlux (1F) software. Site Description - The study was carried out in a 19-ha rainfed soybean plot at the Unidad Integrada Balcarce, located southeast of Buenos Aires, Argentina. The site is located in an environment of gentle hills at 130 m.a.s.l. Its soil was classified as a typical Argiudoll, with a loamy clayey texture up to 0.30 m and between 0.80 to 1.10 m depth, and a clayey texture between 0.30 and 0.80 m depth. The slope was 1:50 and oriented NE to SW. A caliche layer was found at 1 to 1.2 m depth thus the water table was considered beneath that level. The soybean variety used was DM 3810, Maturity Group III with an indeterminate growing habit. It was sown on November 21, 2012, and emerged on December 1. The crop archive had a maximum height of 0.75 m.

Gassmann, Maria Isabel [Universidad de Buenos Aire↗

LLNL Semiannual Wastewater Point Source Monitoring Report (July 2020)

In accordance with the Code of Federal Regulations, Title 40, Part 403.12(e), Lawrence Livermore National Laboratory (LLNL) submits a semiannual monitoring report regarding federally regulated wastewater generating processes (categorical processes) that discharge wastewater to the sanitary sewer system. Attachments A-2 and A-3 of the 2019-2020 Wastewater Discharge Permit #1250 granted to LLNL by the City of Livermore Water Resources Division (WRD) also mandate submission of this report. The LLNL Livermore Site is required to monitor identified electrical and electronic components processes (40 CFR Part 469) and metal finishing processes (40 CFR Part 433) semiannually and to submit monitoring reports in January and July of each year. Under authority delegated to enforce compliance with these regulations, the WRD reviews this report. This report provides information on the significant metal-finishing operations and electrical and electronic component operations located at the Livermore Site during the period from December 1, 2019 through May 31, 2020 and includes descriptions of the LLNL regulated (categorical) processes that discharge to the sanitary sewer. Attachments A-2 and A-3 of the 2019-2020 Wastewater Discharge Permit #1250 provide the list of categorical processes and the required self-monitoring program for point-source discharges at LLNL. The monitoring data collected for this report documents compliance with all federal and local pretreatment limits. Compliance certification accompanies this report, as required by federal regulations.

54 ENVIRONMENTAL SCIENCES↗

Efficient estimation algorithms for a satellite-aided search and rescue mission

It has been suggested to establish a search and rescue orbiting satellite system as a means for locating distress signals from downed aircraft, small boats, and overland expeditions. Emissions from Emergency Locator Transmitters (ELT), now available in most U.S. aircraft are to be utilized in the positioning procedure. A description is presented of a set of Doppler navigation algorithms for extracting ELT position coordinates from Doppler data. The algorithms have been programmed for a small computing machine and the resulting system has successfully processed both real and simulated Doppler data. A software system for solving the Doppler navigation problem must include an orbit propagator, a first guess algorithm, and an algorithm for estimating longitude and latitude from Doppler data. Each of these components is considered.

Argentiero, P.↗

The 34-meter antenna drive control system

Detailed definitions of the baseline antenna drive and control/instrumentation equipment for 34 meter antennas included in Network Consolidation Program of the Deep Space Network are presented. The overall antenna control and monitor system and its interfaces with other higher level control and monitor equipment is described. Explicit descriptions of the antenna axis drive motors and motor controllers, the axis angle encoding systems, and miscellaneous antenna located components are presented, and related to system functional and performance requirements. Some potential alternates to the baseline system configuration are described and discussed.

Source record↗

Measurement of heavy cosmic rays above 20 GeV/n in passive detectors - Preliminary results from JACEE-3

It is pointed out that the JACEE-3 experiment combined electronic counters and an emulsion chamber to study nucleus-nucleus interactions between 20 and 100 GeV/n. In the present paper, a description is given of the use of the passive detector stack. The electronic position detectors facilitate the event location, taking into account a determination of the incident angles. CR-39 plastic plates were placed just below the proportional counters to enhance tracking accuracy. The JACEE-3 emulsion chamber consists of three parts, including the charge module, the target module, and the calorimeter module. The charge module is mainly used in track identification. The obtained results are also discussed, giving attention to event number and tracking efficiency, interaction measurements, and the inelasticity distribution.

Burnett, T. H.↗

Prediction of rocket plume radiative heating using backward Monte-Carlo method

A backward Monte-Carlo plume radiation code has been developed to predict rocket plume radiative heating to the rocket base region. This paper provides a description of this code and provides sample results. The code was used to predict radiative heating to various locations during test firings of 48-inch solid rocket motors at NASA Marshall Space Flight Center. Comparisons with test measurements are provided. Predictions of full scale sea level Redesigned Solid Rocket Motor (RSRM) and Advanced Solid Rocket Motor (ASRM) plume radiative heating to the Space Shuttle external tank (ET) dome center were also made. A comparison with the Development Flight Instrumentation (DFI) measurements is also provided.

Wang, K. C.↗

Design of a lunar propellant processing facility. NASA/USRA advanced program

Mankind's exploration of space will eventually lead to the establishment of a permanent human presence on the Moon. Essential to the economic viability of such an undertaking will be prudent utilization of indigenous lunar resources. The design of a lunar propellant processing system is presented. The system elements include facilities for ore processing, ice transportation, water splitting, propellant storage, personnel and materials transportation, human habitation, power generation, and communications. The design scenario postulates that ice is present in the lunar polar regions, and that an initial lunar outpost was established. Mining, ore processing, and water transportation operations are located in the polar regions. Water processing and propellant storage facilities are positioned near the equator. A general description of design operations is outlined below. Regolith containing the ice is mined from permanently-shaded polar craters. Water is separated from the ore using a microwave processing technique, and refrozen into projectiles for launch to the equatorial site via railgun. A mass-catching device retrieves the ice. This ice is processed using fractional distillation to remove impurities, and the purified liquid water is fed to an electrolytic cell that splits the water into vaporous hydrogen and oxygen. The hydrogen and oxygen are condensed and stored separately in a tank farm. Electric power for all operations is supplied by SP-100 nuclear reactors. Transportation of materials and personnel is accomplished primarily using chemical rockets. Modular living habitats are used which provide flexibility for the placement and number of personnel. A communications system consisting of lunar surface terminals, a lunar relay satellite, and terrestrial surface stations provides capabilities for continuous Moon-Moon and Moon-Earth transmissions of voice, picture, and data.

Batra, Rajesh↗

Large Solar Observatory

This article summarizes the scientific aim, design considerations and observatory site of a large optical solar telescope. The day time "seeing" is better on the islands, surrounded by large body of water, compared to the mountain sites. Therefore, in order to obtain the solar images with sub-arcsec resolution, the observatory site should be preferably located on an island. A list of potential sites on Himalayas and surrounding region is given. A brief description of the telescope design, enclosure and back-end instruments are also presented.

Choudhary, Debi Prasad↗

[Columbia Sensor Diagrams]

A two dimensional graphical event sequence of the time history of relevant sensor information located in the left wing and wheel well areas of the Space Shuttle Columbia Orbiter is presented. Information contained in this graphical event sequence include: 1) Sensor location on orbiter and its associated wire bindle in X-Y plane; 2) Wire bundle routing; 3) Description of each anomalous sensor event; 4) Time annotation by (a) GMT, (b) time relative to LOS, (c) time history bar, and (d) ground track; and 5) Graphical display of temperature rise (based on delta temperature from point it is determined to be anomalous).

Source record↗

Constraints on the Lithological Variation near the Surface of the HED Planetoid from the Petrology of 91 & 92 Series Antarctic Achondrites

The petrography of a suite of meteorite sections: PCA91006,14; PCA91078,9; PCA91083,6; PCA91159,4; PCA91179,9; PCA91245,9; EET92003,14; EET92004,12; EET92015,4; EET92022,7; EET92026,4; and EET92027,5 is used as an initial sample of the lithological variation on the surface of the HED planetoid (presumably asteroid 4 Vesta). These samples will be combined with much larger arrays of petrographic data for the many Antarctic basaltic achondrites to provide a random sample of the surface of the body. The full variety of the lithologies existing on the parent body is only accessible when the polymict achondrites are considered. The polymict samples contain lithologies that sample multiple provenances as well as those not seen as monolithologic meteorites like eucrites and diogenites. Comparison of lithological variation within individual meteorites provides a subset of variations at the site of last impact. In aggregate, the variations within the achondrites now available may be close to a random sample of the parent body. In combination of microanalytical and imaging techniques now available permit a mass balanced assessment of the distribution and abundance of lithologies to be made. These initial results provide a description of methodology to be tested. All samples were studied and photographed on a polarizing microscope to provide location information. Major mineral phases and randomly selected points (on lines and grids) were analyzed in each thin section. In addition backscattered electron and X-ray imaging of clasts and sections provide the basis for high precision modal analyses of the abundance and distribution of both lithic and mineral clasts. These data provide objective, area based comparisons with other Antarctic samples.

Bjonnes, Emily E.↗

Preliminary description of Apollo 15 sample environments

Approximately 78 kg of lunar rock and soil samples were returned by Apollo 15. The rather complete documentation of the locations of nearly all of the samples allows for relating the samples to the specific and detailed geologic environments from which they were collected. This is especially important in an area as geologically complex as the Hadley-Apennine site. All of the material presented was derived from the pre-mission photogeologic maps, lunar surface television video tapes, air-to-ground transcript and crew debriefings, photographs taken on the lunar surface by the Apollo 15 crew, and information supplied by the Lunar Sample Preliminary Examination team from which the samples were categorized into groups consisting of, broadly, basalts and breccias. The breccias are considered loosely in terms of coherent breccias and soil breccias.

Swann, G. A.↗

Apollo 14 coarse fines (4-10 mm) sample location and classification

The 4 to 10 mm sieve fraction from the soil samples collected during the Apollo 14 Mission was identified and described. Examination and description of the fines were carried out in nitrogen-filled, stainless steel cabinets during a general examination of the Apollo 14 sample collection. Each particle was held between forceps, dusted in a jet of N2, and placed on a teflon-covered stage. They were examined with a binocular microscope, separated by lithology, and the lithologic types described. Weights of individual particles in the fraction ranged from about 0.10 to 0.50 gm, large enough in size for studies of age, chemistry, and petrology to be accomplished.

Kramer, F. E.↗

Use of 3000 Bragg Grating Strain Sensors Distributed on Four Eight-meter Optical Fibers During Static Load Tests of a Composite Structure

This paper describes the use of a fiber optic system to measure strain at thousands of locations along optical fibers where weakly reflecting Bragg gratings have been photoetched. The optical fibers were applied to an advanced composite transport wing along with conventional foil strain gages. A comparison of the fiber optic and foil gage systems used for this test will be presented including: a brief description of both strain data systems; a discussion of the process used for installation of the optical fiber; comparative data from the composite wing test; the processes used for the location and display of the high density fiber optic data. Calibration data demonstrating the potential accuracy of the fiber optic system will also be presented. The opportunities for industrial and commercial applications will be discussed. The fiber optic technique is shown to be a valuable augmentation to foil strain gages providing insight to structural behavior previously requiring reliance on modeling.

Childers, Brooks A.↗

Design description of the Tangaye Village photovoltaic power system

The engineering design of a stand alone photovoltaic (PV) powered grain mill and water pump for the village of Tangaye, Upper Volta is described. The socioeconomic effects of reducing the time required by women in rural areas for drawing water and grinding grain were studied. The suitability of photovoltaic technology for use in rural areas by people of limited technical training was demonstrated. The PV system consists of a 1.8-kW (peak) solar cell array, 540 ampere hours of battery storage, instrumentation, automatic controls, and a data collection and storage system. The PV system is situated near an improved village well and supplies d.c. power to a grain mill and a water pump. The array is located in a fenced area and the mill, battery, instruments, controls, and data system are in a mill building. A water storage tank is located near the well. The system employs automatic controls which provide battery charge regulation and system over and under voltage protection. This report includes descriptions of the engineering design of the system and of the load that it serves; a discussion of PV array and battery sizing methodology; descriptions of the mechanical and electrical designs including the array, battery, controls, and instrumentation; and a discussion of the safety features. The system became operational on March 1, 1979.

Martz, J. E.↗