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At least 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Pseudomonas aeruginosa gene PA4880 encodes a Dps-like protein with a Dps fold, bacterioferritin-type ferroxidase centers, and endonuclease activity

We report the biochemical, structural, and functional characterization of the protein coded by gene PA4880 in the P. aeruginosa PAO1 genome. The PA4880 gene had been annotated as coding a probable bacterioferritin. Our structural work shows that the product of gene PA4880 is a protein that adopts the Dps subunit fold, which oligomerizes into a 12-mer quaternary structure. Unlike Dps, however, the ferroxidase di-iron centers and iron coordinating ligands are buried within each subunit, in a manner identical to that observed in the ferroxidase center of P. aeruginosa bacterioferritin. Since these structural characteristics correspond to Dps-like proteins, we term the protein as P. aeruginosa Dps-like, or Pa DpsL. The ferroxidase centers in Pa DpsL catalyze the oxidation of Fe 2+ utilizing O 2 or H 2 O 2 as oxidant, and the resultant Fe 3+ is compartmentalized in the interior cavity. Interestingly, incubating Pa DpsL with plasmid DNA results in efficient nicking of the DNA and at higher concentrations of Pa DpsL the DNA is linearized and eventually degraded. The nickase and endonuclease activities suggest that Pa DpsL, in addition to participating in the defense of P. aeruginosa cells against iron-induced toxicity, may also participate in the innate immune mechanisms consisting of restriction endonucleases and cognate methyl transferases.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1972

The National Space Science Data Center guide to international rocket data

Background information is given which briefly describes the mission of the National Space Science Data Center (NSSDC), including its functions and systems, along with its policies and purposes for collecting rocket data. The operation of a machine-sensible rocket information system, which allows the Data Center to have convenient access to information and data concerning all rocket flights carrying scientific experiments, is also described. The central feature of this system, an index of rocket flights maintained on magnetic tape, is described. Standard outputs for NSSDC and for the World Data Center A (WDC-A) for Rockets and Satellites are described.

Dubach, L. L.↗
NASA NTRS1971

Flight Research Center, Edwards, California. Environmental Impact Statement

This is an institutional environmental impact statement relating to the overall operation of the NASA, Flight Research Center. The Center is located in Kern County, California, approximately 100 miles northeast of Los Angeles. Flight activities relate primarily to areas in the vicinity of Los Angeles, Kern, Inyo and San Bernardino counties in Southern California; and to areas in Southern Nevada (principally Nye and Clark counties. Operations of the Flight Research Center have a very neglibible impact on the environment; and they are planned and controlled to eliminate or minimize effects on water, air and noise.

Source record↗
NASA NTRS1971

Final environmental impact statement for Ames Research Center

The NASA-Ames Research Center is described. together with the nature of its activities, from which it can be seen that the center is basically not a major pollution source. Geographical, and climatic characteristics of the site are described. inasmuch as they influence both the choice of disposal methods and the environmental effects of the pollutants. The known or probable pollution sources at the center are described. Where the intensities of these sources might exceed the recommended guidelines, the corrective actions that have been taken are described.

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NASA NTRS1972

The management approach to the NASA space station definition studies at the Manned Spacecraft Center

The overall management approach to the NASA Phase B definition studies for space stations, which were initiated in September 1969 and completed in July 1972, is reviewed with particular emphasis placed on the management approach used by the Manned Spacecraft Center. The internal working organizations of the Manned Spacecraft Center and its prime contractor, North American Rockwell, are delineated along with the interfacing techniques used for the joint Government and industry study. Working interfaces with other NASA centers, industry, and Government agencies are briefly highlighted. The controlling documentation for the study (such as guidelines and constraints, bibliography, and key personnel) is reviewed. The historical background and content of the experiment program prepared for use in this Phase B study are outlined and management concepts that may be considered for future programs are proposed.

Heberlig, J. C.↗
NASA NTRS1974

An overview of the National Space Science data Center Standard Information Retrieval System (SIRS)

A general overview is given of the National Space Science Data Center (NSSDC) Standard Information Retrieval System. A description, in general terms, the information system that contains the data files and the software system that processes and manipulates the files maintained at the Data Center. Emphasis is placed on providing users with an overview of the capabilities and uses of the NSSDC Standard Information Retrieval System (SIRS). Examples given are taken from the files at the Data Center. Detailed information about NSSDC data files is documented in a set of File Users Guides, with one user's guide prepared for each file processed by SIRS. Detailed information about SIRS is presented in the SIRS Users Guide.

Shapiro, A.↗
NASA NTRS1974

The problem of organization of a coastal coordinating computer center

The fundamental principles of the operation of a coastal coordinating and computing center under conditions of automation are presented. Special attention is devoted to the work of Coastal Computer Center of the Arctic and Antarctic Scientific Research Institute. This center generalizes from data collected in expeditions and also from observations made at polar stations.

Dyubkin, I. A.↗
NASA NTRS1976

Baseline meteorological soundings for parametric environmental investigations at Kennedy Space Center and Vandenberg Air Force Base

Meteorological soundings representative of the atmospheric environment at the Kennedy Space Center, Florida and Vandenberg Air Force Base, California, are presented. Synthetic meteorological soundings at Kennedy Space Center, including fall, spring, and a sea breeze, and at Vandenberg Air Force Base (sea breeze with low and high level inversion and stationary upper level troughs) are shown. Soundings of frontal passages are listed. The Titan launch soundings at Kennedy Space Center present a wide range of meteorological conditions, both seasonal and time of day variations. The meteorological data input of altitude, wind speed, wind direction, temperature, and pressure may be used as meteorological inputs for the NASA/MSFC Multilayer Diffusion Model or other models to obtain quantitative estimates of effluent concentrations associated with the potential emission of major combustion products in the lower atmosphere to simulate actual launches of space vehicles. The Titan launch soundings are also of value in terms of rocket effluent measurements for analysis purposes.

Susko, M.↗
NASA NTRS1975

Effect of the mass center shift for force-free flexible spacecraft

For a spinning flexible spacecraft the mass center generally shifts relative to the nominal undeformed position. It is thought that this shift of center complicates spacecraft stability analysis. It is proved, on the basis of results achieved by Meirovitch and Calico (1972), that for the general class of force-free single-spin flexible spacecraft it is possible to ignore this shift of center without affecting the stability criteria in any significant way. A new theorem on inequalities for quadratic forms is proved to demonstrate the validity of the stability analysis.

Meirovitch, L.↗
NASA NTRS1976

Program for establishing long-time flight service performance of composite materials in the center wing structure of C-130 aircraft. Phase 4: Ground/flight acceptance tests

The advantageous structural uses of advanced filamentary composites are demonstrated by design, fabrication, and test of three boron-epoxy reinforced C-130 center wing boxes. The advanced development work necessary to support detailed design of a composite reinforced C-130 center wing box was conducted. Activities included the development of a basis for structural design, selection and verification of materials and processes, manufacturing and tooling development, and fabrication and test of full-scale portions of the center wing box. Detailed design drawings, and necessary analytical structural substantiation including static strength, fatigue endurance, flutter, and weight analyses are considered. Some additional component testing was conducted to verify the design for panel buckling, and to evaluate specific local design areas. Development of the cool tool restraint concept was completed, and bonding capabilities were evaluated using full-length skin panel and stringer specimens.

Harvill, W. E.↗
NASA NTRS1977

Survey: Federal Aviation Administration National Communication Center

The National Communication (NATCOM) Center (commonly known as the FAA Weather Message Switching Center), is a Federal Aviation Administration (FAA) facility with responsibility for providing communication switching services to the National Weather Service (NWS), the FAA, commercial and private flight organizations under the auspices of the FAA, and DoD. Data handled by NATCOM include weather data, flight plans, and Notices to Airmen (NOTAMS) on both national and international networks. The communications and data management functions are handled through four computer-controlled communication networks designated as WMSC, AFTN, A-BDIS, and NASNET. The functions of these networks are discussed with emphasis on those networks that support the different elements of the NWS. The primary network of concern to NASA, the WMSC (Weather Message Switching Center) network, performs approximately 60 percent of its work for the NWS, 20 percent for the State Department, and 20 percent for the FAA. This document discusses the current and future systems capabilities and workload of NATCOM in terms of new roles.

Source record↗
NASA NTRS1977

Survey: National Meteorological Center

The National Meteorological Center (NMC) is comprised of three operational divisions (Development, Automation, and Forecast) and an Administrative Division. The Development Division develops and implements mathematical models for forecasting the weather. The Automation Division provides the software and processing services to accommodate the models used in daily forecasts. The Forecasting Division applies a combination of numerical and manual techniques to produce analyses and prognoses up to 120 hr into the future. This guidance material is combined with severe storm information from the National Hurricane Center and the National Severe Storms Forecasting Center to develop locally tailored forecasts by the Weather Service Forecast Offices and, in turn, by the local Weather Service Offices. A very general flow of this information is shown. A more detailed illustration of data flow into, within, and from the NMC is given. The interrelations are depicted between the various meteorological organizations and activities.

Source record↗
NASA NTRS1978

A highly accurate method for the determination of mass and center of mass of a spacecraft

An extremely accurate method for the measurement of mass and the lateral center of mass of a spacecraft has been developed. The method was needed for the Voyager spacecraft mission requirement which limited the uncertainty in the knowledge of lateral center of mass of the spacecraft system weighing 750 kg to be less than 1.0 mm (0.04 in.). The method consists of using three load cells symmetrically located at 120 deg apart on a turntable with respect to the vertical axis of the spacecraft and making six measurements for each load cell. These six measurements are taken by cyclic rotations of the load cell turntable and of the spacecraft, about the vertical axis of the measurement fixture. This method eliminates all alignment, leveling, and load cell calibration errors for the lateral center of mass determination, and permits a statistical best fit of the measurement data. An associated data reduction computer program called MASCM has been written to implement this method and has been used for the Voyager spacecraft.

Chow, E. Y.↗
NASA NTRS1978

Galactic center iron line emission

Data from the Goddard Space Flight Center experiment on HEAO 1 were examined for galactic center iron line emission. Evidence for a 6.8 keV line from the summed flux within 10 deg longitude and 10 deg latitude of the galactic center was found; however, firm limits cannot be put on the intrinsic line width. If the line emission is diffuse and cosmic-ray-induced, the calculations of Bussard et al (1978) yield an upper limit to c-12 4.44 MeV line emission, which is not inconsistent with the results of Haymes et al (1975). Significant contributions to the iron line from discrete sources can not be ruled out.

Worrall, D. M.↗
NASA NTRS1977

Ne II 12.8 micron emission from the galactic center. II

Recent observations of the 12.8-micron Ne II emission from the galactic center have revealed a region of primarily blueshifted emission in addition to the previously detected redshifted emission. It appears most likely that the blueshifted and redshifted emission come from separate clouds and that the dynamics of the ionized gas is dominated by the gravitational potential of the massive core at the galactic center. On the basis of the velocities and velocity dispersions, the total mass within a radius of 1 pc about the galactic center is estimated to be of the order of 4 million solar masses.

Wollman, E. R.↗
NASA NTRS1980

Adjustable base for centering staked bearings

Adjustable base permits housing and race to be supported separately so that unequal widths can be accounted for and bearing staked on center. If race is centered and staked on flat base and housing and race are not same width, then offset may occur and bearing will be set off center.

Berson, L. A.↗
NASA NTRS1978

Airborne measurements of cloud forming nuclei and aerosol particles at Kennedy Space Center, Florida

Results of airborne measurements of the sizes and concentrations of aerosol particles, ice nuclei, and cloud condensation nuclei that were taken at Kennedy Space Center, Florida, are presented along with a detailed description of the instrumentation and measuring capabilities of the University of Washington airborne measuring facility (Douglas B-23). Airborne measurements made at Ft. Collins, Colorado, and Little Rock, Arkansas, during the ferry of the B-23 are presented. The particle concentrations differed significantly between the clean air over Ft. Collins and the hazy air over Little Rock and Kennedy Space Center. The concentrations of cloud condensation nuclei over Kennedy Space Center were typical of polluted eastern seaboard air. Three different instruments were used to measure ice nuclei: one used filters to collect the particles, and the others used optical and acoustical methods to detect ice crystals grown in portable cloud chambers. A comparison of the ice nucleus counts, which are in good agreement, is presented.

Radke, L. F.↗