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At least 1,729 records · Page 96

Water hyacinths for upgrading sewage lagoons to meet advanced wastewater treatment standards, part 2

Field tests using water hyacinths as biological filtration agents were conducted in the Mississippi gulf coast region. The plants were installed in one single cell and one multiple cell sewage lagoon systems. Water hyacinths demonstrated the ability to maintain BOD5 and total suspended solid (TSS) levels within the Environmental Protection Agency's prescribed limits of 30 mg/lBOD5 and 30 mg/l TSS. A multiple cell sewage lagoon system consisting of two aerated and one water hyacinth covered cell connected in series demonstrated the ability to maintain BOD5 and TSS levels below 30 mg/l year-round. A water hyacinth covered lagoon with a surface area of 0.28 hectare containing a total volume of 6.8 million liters demonstrated the capacity to treat 437,000 to 1,893,000 liters of sewage influent from 2.65 hectares of aerated lagoons daily and produce an effluent that met or exceeded standards year-round.

Wolverton, B. C.↗

Drag reduction obtained by modifying a standard truck

A standard two-axle truck with a box-shaped cargo compartment was tested to determine whether significant reductions in aerodynamic drag could be obtained by modifying the front of the cargo compartment. The coastdown method was used to determine the total drag of the baseline vehicle, which had a square-cornered cargo box, and of several modified configurations. Test velocities ranged from 56.3 to 94.6 kilometers per hour (35 to 60 miles per hour). At 88.5 kilometers per hour (55 miles per hour), the aerodynamic drag reductions obtained with the modified configurations ranged from 8 to 30 percent.

Sheridan, A. E.↗

Standard techniques for presentation and analysis of crater size-frequency data

In September 1977, a crater studies workshop was held for the purpose of developing standard data analysis and presentation techniques. This report contains the unanimous recommendations of the participants. This first meeting considered primarily crater size-frequency data. Future meetings will treat other aspects of crater studies such as morphologies.

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Study of Improvement of Hydrogen Maser Frequency Standard

The research work dealt primarily with reducing the atom leakage rate using as storage surfaces the FEP Teflon surfaces conventionally used in contemporary hydrogen maser frequency standards. Some work was also done on a possible alternative to the conventional surfaces, but the results here and elsewhere suggest that the alternative surface is not promising enough to warrant much further work.

Crampton, S. B.↗

LANDSAT 2 world standard catalog, 1 Jan. - 30 Apr. 1978

The World Standard Catalog lists imagery acquired by LANDSAT 2 which has been processed and input to the data files during the referenced months. Data, such as cloud cover and image quality, are given for each scene. The microfilm roll and frame on which the scene may be found is also given.

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Standard practices for the implementation of computer software

A standard approach to the development of computer program is provided that covers the file cycle of software development from the planning and requirements phase through the software acceptance testing phase. All documents necessary to provide the required visibility into the software life cycle process are discussed in detail.

Irvine, A. P.↗

A computer version of the US Standard Atmosphere, 1978

A computer version of the U.S. Standard Atmosphere, 1976, was developed. The computer program was developed in modular form for easy incorporation into the user's program and for easy modification for specialized uses.

King, R. L.↗

Evaluation of the developing DSN life-cycle cost standard practice

The DSN is developing a life-cycle cost standard practice by comparison to those of industry and the Department of Defense. Results show that the DSN uses the accepted concept of life-cycle costing, tailoring the concept to DSN specific needs, but does not push the concept past the point of prevailing theory.

Mckenzie, M.↗

LANDSAT 3 world standard catalog, 6 March - 31 July 1978

The World Standard Catalog lists imagery acquired by LANDSAT 3 which was processed and input to the data files during the referenced period. Information such as date of entry, cloud cover, and image quality is given for each scene. The microfilm roll and frame on which the scene may be found is also indicated.

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Standard wool fabric as a reference material

Standard wool fabric is investigated as a potential reference material. A screening test method for relative toxicity exposes four albino male rats enclosed in a 4.2 liter hemispherical chamber to pyrolysis effluents produced by pyrolyzing a 1.00 g sample under a variety of test conditions (200-800 C with a 40 C/min heating rate). It is found that for fabrics containing 86-100% wool, animal response remains virtually unchanged, although a 100% wool fabric is preferred as it eliminates local composition differences as a source of variation.

Hilado, C. J.↗

Standard Molded Composite Rocket Pyrogen Igniter - A progress report

The pyrogen igniter has the function to furnish a controlled, high temperature, high pressure gas to ignite solid propellant surfaces in a rocket motor. Present pyrogens consist of numerous inert components. The Standard Molded Pyrogen Igniter (SMPI) consists of three basic parts, a cap with several integrally molded features, an ignition pellet retainer plate, and a tube with additional integrally molded features. A description is presented of an investigation which indicates that the SMPI concept is a viable approach to the design and manufacture of pyrogen igniters for solid propellant rocket motors. For some applications, combining the structural and thermal properties of molded composites can result in the manufacture of lighter assemblies at considerable cost reduction. It is demonstrated that high strength, thin walled tubes with high length to diameter ratios can be fabricated from reinforced plastic molding compound using the displacement compression process.

Lucy, M. H.↗

NASA standard Multimission Modular Spacecraft for future space exploration

The design of the Multimission Modular Spacecraft (MMS) has evolved over the past seven years. The main objective concerning the design of the MMS has been related to aspects of cost effectiveness. Maximum use was to be made of NASA standard components. The basic concept has been to design a core spacecraft which has inherent flexibility to meet a range of mission needs without modification of its hardware elements. An overview is provided of the MMS performance capability and the current status of the MMS program. The MMS is the first NASA approved active control free-flying spacecraft to be designed to be Shuttle compatible. The design of the MMS is such that no single failure will preclude its retrieval by the Shuttle.

Bartlett, R. O.↗

Group-delay standards

Delay-line standards have been tested by three independent laboratories using six different methods. Results are published in report showing delay values obtained from 15-, 30-, and 60-ns cables by different laboratories. Study of potential error sources indicates that reflection errors due to discontinuities at ends of cables are usually small.

Beatty, R. W.↗

Hydrogen maser frequency standard computer model for automatic cavity tuning servo simulations

A computer model of the JPL hydrogen maser frequency standard was developed. This model allows frequency stability data to be generated, as a function of various maser parameters, many orders of magnitude faster than these data can be obtained by experimental test. In particular, the maser performance as a function of the various automatic tuning servo parameters may be readily determined. Areas of discussion include noise sources, first-order autotuner loop, second-order autotuner loop, and a comparison of the loops.

Potter, P. D.↗

LANDSAT 2 world standard catalog, 1-31 October 1978

The World Standard Catalog lists imagery acquired by LANDSAT 2 which was processed and input to the data files during the referenced period. Information such as cloud cover and image quality is given for each scene. The microfilms roll and frame on which the scene may be found is also given.

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LANDSAT 2 world standard catalog, 1-30 November 1978

The World Standard Catalog lists imagery acquired by LANDSAT 2 which was processed and input to the data files during the referenced period. Information such as cloud cover and image quality is given for each scene. The microfilm roll and frame on which the scene may be found is also given.

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LANDSAT 3 world standard catalog, 1-31 December 1978

The World Standard Catalog lists imagery acquired by LANDSAT 3 which was processed and input to the data files during the referenced period. Information on cloud cover and image quality is given for each scene. The microfilm roll and frame on which the scene may be found is given.

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LANDSAT 2 world standard catalog, 1-31 December 1978

The World Standard Catalog lists imagery acquired by LANDSAT 2 which was processed and input to the data files during the referenced period. Information on cloud cover and image quality is given for each scene. The microfilm roll and frame on which the scene may be found is presented.

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