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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

New analysis of nuclear interaction observed by Mt. Kanbara emulsion chamber experiment

To date the analysis of the air cascade family has been performed using a full Monte Carlo simulation. It is difficult to draw a definite conclusion about the interaction mechanism by using only this kind of simulation. On the other hand, attempts to reproduce the original gamma ray at the interaction point, for example decascading, have also been made. This method makes it possible to observe the interaction directly and to analyze the data from various angles. All of these methods, however, assume a constant ER in the cascade shower, where E is energy and R is the distance from the center of the cascade shower. It is impossible to reproduce the exact interaction height and energy by these methods. A relative method in separating one cascade shower from others is adopted. This method makes it possible to estimate the interaction height and energy by using information about the lateral spread of the cascade shower.

Nanjo, H.↗
NASA NTRS2021

Chapter 3: Suspensions, foams, emulsions, colloids, and granular materials--self-healing, tuning gravity, and life support for exploration

At the suggestion of NASA’s Physical Science Research Program in the Space Life and Physical Science Research and Application Division, Paul Chaikin, Noel Clark, and Sidney Nagel organized a focus session and workshop for the 2020 American Physical Society (APS) March meeting under the auspices of the Division of Soft Matter. Three overarching themes emerged from the workshop and are presented with additional details: • Machines made out of machines • Scalable self-sustaining ecosystems • Active materials and metamaterials This report lays out only some of the potential directions for soft matter dynamics over the next two decades. It also lays out the role that gravity plays in the organization of the basic building blocks of matter. Not only will research on soft matter have tremendous application towards understanding its behavior in our terrestrial environment, but also potentially in other NASA programs such as planetary science, exploration, robotics, etc. Attached is a White Paper for the Decadal Survey that consists of an extended Title along with the previous Introduction and Chapter 2.3 from NASA/CP-20205010493.

Soft matter↗
NASA NTRS1975

Method of producing a storage bulb for an atomic hydrogen maser

A storage bulb for an atomic hydrogen maser is produced by coating its internal surface with an emulsion containing both TFE and FEP particles. The emulsion is produced by mixing a first quantity of TFE in an aqueous dispersion with a second quantity of FEP in an aqueous dispersion, with a third quantity of distilled water. The emulsion is poured into the bulb to coat it uniformly so as to form a thin film of emulsion on the bulb's internal surface. After excess emulsion is drained out of the bulb the emulsion in the bulb is dried to remove the water and most of the aqueous matter therefrom. The remaining emulsion is then cured by heating the bulb to a temperature of at least 380 C.

Erpenbach, H.↗
NASA NTRS1984

Effects of shuttle bay environment on UV sensitive photographic film results of measurements aboard STS-7 and STS-8

Schumann emulsions, having low gelatin content and no protective gelatin overcoating, are extremely sensitive to environmental conditions and handling. Experiments using this emulsion are to be flown on the space shuttle within the cargo-bay. Because the environment of the cargo-bay is unknown, a Get-Away-Special payload was designed to expose Kodak-type SO 652 Schumann emulsion to the residual atmosphere of the cargo-bay. The experiment was programmed to make exposures for various time periods to determine the maximum length of time the film could be exposed in making a measurement and what precautions would be required to preserve the film during ascent into orbit and reentry. The results of the STS-7 and STS-8 flights indicated that long exposures in the shuttle bay do not produce high fog levels in orbit. Observations of severe bleaching of the latent image makes protection of the emulsion during reentry manditory and increase of fog levels with time set a limit of four weeks (preferably less than three) between installation and recovery of the emulsion for processing.

Kreplin, R. W.↗
NASA NTRS1985

Structure of super-families

At present the study of nuclear interactions induced by cosmic rays is the unique source of information on the nuclear interactions in the energy region above 10 to the 15th power eV. The phenomena in this energy region are observed by air shower arrays or emulsion chambers installed at high mountain. An emulsion chamber is the pile of lead plates and photo-sensitive layers (nuclear emulsion plates and/or X-ray films) used to detect electron showers. High spatial resolution of photographic material used in the emulsion chamber enables the observation of the phenomena in detail, and recent experiments of emulsion chamber with large area are being carried out at high mountain altitudes by several groups in the world.

Yamashita, S.↗
NASA NTRS1984

Production of large-particle-size monodisperse latexes

The research program achieved two objectives: (1) it has refined and extended the experimental techniques for preparing monodisperse latexes in quantity on the ground up to a particle diameter of 10 microns; and (2) it has demonstrated that a microgravity environment can be used to grow monodisperse latexes to larger sizes, where the limitations in size have yet to be defined. The experimental development of the monodisperse latex reactor (MLR) and the seeded emulsion polymerizations carried out in the laboratory prototype of the flight hardware, as a function of the operational parameters is discussed. The emphasis is directed towards the measurement, interpretation, and modeling of the kinetics of seeded emulsion polymerization and successive seeded emulsion polymerization. The recipe development of seeded emulsion polymerization as a function of particle size is discussed. The equilibrium swelling of latex particles with monomers was investigated both theoretically and experimentally. Extensive studies are reported on both the type and concentration of initiators, surfactants, and inhibitors, which eventually led to the development of the flight recipes. The experimental results of the flight experiments are discussed, as well as the experimental development of inhibition of seeded emulsion polymerization in terms of time of inhibition and the effect of inhibitors on the kinetics of polymerization.

Vanderhoff, J. W.↗
NASA NTRS1989

Direct electron-pair production by high energy heavy charged particles

Direct electron pain production via virtual photons by moving charged particles is a unique electro-magnetic process having a substantial dependence on energy. Most electro-magnetic processes, including transition radiation, cease to be sensitive to the incident energy above 10 TeV/AMU. Thus, it is expected, that upon establishment of cross section and detection efficiency of this process, it may provide a new energy measuring technique above 10 TeV/AMU. Three accelerator exposures of emulsion chambers designed for measurements of direct electron-pains were performed. The objectives of the investigation were to provide the fundamental cross-section data in emulsion stacks to find the best-fit theoretical model, and to provide a calibration of measurements of direct electron-pairs in emulsion chamber configurations. This paper reports the design of the emulsion chambers, accelerator experiments, microscope measurements, and related considerations for future improvements of the measurements, and for possible applications to high energy cosmic ray experiments. Also discussed are the results from scanning 56m of emulsion tracks at 1200x magnification so that scanning efficiency is optimized. Measurements of the delta-ray range spectrum were also performed for much shorter track lengths, but with sufficiently large statistics in the number of measured delta-rays.

Takahashi, Y.↗
NASA NTRS1972

Solar wind photoplate study

An ion sensitive emulsion detection system has been considered for use in a cycloidal focusing mass spectrometer to measure the various atomic species which comprise the solar plasma. The responses of Ilford Q2 and Kodak SC7 emulsions were measured with N(+) ions at 6 keV to 10 keV, He(++) ions at 750 eV to 2500 eV, and H(+) ions at 550 eV to 1400 eV. These ions have the approximate range of velocities (about 300-500 km/sec) encountered in the solar wind. The work was carried out on a specially prepared magnetic sector mass analyzer. Characteristic response curves were generated, each one utilizing approximately 50 data points at three or more current densities. In addition to the ion response, measurements of the response of these emulsions to a photon flux simulating the visible portion of the solar spectrum were made. The results obtained will be presented in detail and interpreted in relation to other data available for these emulsions.

Scott, B. W.↗
NASA NTRS1978

A note on the tissue star dose in personnel radiation monitoring in space

Secondaries from nuclear interactions of high energy primaries in the body tissues themselves contribute substantially to the astronaut's radiation exposure in space. The so-called tissue star dose is assessed from the prong number distribution of disintegration stars in emulsion. Prong counts of 1,000 emulsion stars from the Apollo-Soyuz mission reported earlier were re-evaluated. The original scores were divided into sets of 250, 500, 750, and 1,000 emulsion stars and the respective prong number distributions established. The statistical error of the gelatin star number for the four consecutively larger was found to vary, on the 67 percent confidence level, from + or - 25 percent for the count of 250 emulsion stars to + or - 11 percent for 1,000 stars. Seen in the context of the other limitations of the experimental design, the lowest effort of prong-counting 250 stars appears entirely appropriate.

Schaefer, H. J.↗
NASA NTRS2006

Contaminant Removal From Natural Resources

A zero-valent metal emulsion containing zero-valent metal particles is used to remediate contaminated natural resources, such as groundwater and soil. In a preferred embodiment, the zero-valent metal emulsion removes heavy metals, such as lead (pb), from contaminated natural resources. In another preferred embodiment, the zero-valent metal emulsion is a bimetallic emulsion containing zero-valent metal particles doped with a catalytic metal to remediate halogenated aromatic compounds, such as polychlorinated biphenyls (PCBs), from natural resources.

Clausen, Christian A.↗
NASA NTRS2005

Field demonstration of DNAPL dehalogenation using emulsified zero-valent iron

This paper describes the results of the first field-scale demonstration conducted to evaluate the performance of nanoscale emulsified zero-valent iron (EZVI) injected into the saturated zone to enhance in situ dehalogenation of dense, nonaqueous phase liquids (DNAPLs) containing trichloroethene (TCE). EZVI is an innovative and emerging remediation technology. EZVI is a surfactant-stabilized, biodegradable emulsion that forms emulsion droplets consisting of an oil-liquid membrane surrounding zero-valent iron (ZVI) particles in water. EZVI was injected over a five day period into eight wells in a demonstration test area within a larger DNAPL source area at NASA's Launch Complex 34 (LC34) using a pressure pulse injection method. Soil and groundwater samples were collected before and after treatment and analyzed for volatile organic compounds (VOCs) to evaluate the changes in VOC mass, concentration and mass flux. Significant reductions in TCE soil concentrations (>80%) were observed at four of the six soil sampling locations within 90 days of EZVI injection. Somewhat lower reductions were observed at the other two soil sampling locations where visual observations suggest that most of the EZVI migrated up above the target treatment depth. Significant reductions in TCE groundwater concentrations (57 to 100%) were observed at all depths targeted with EZVI. Groundwater samples from the treatment area also showed significant increases in the concentrations of cis-1,2-dichloroethene (cDCE), vinyl chloride (VC) and ethene. The decrease in concentrations of TCE in soil and groundwater samples following treatment with EZVI is believed to be due to abiotic degradation associated with the ZVI as well as biodegradation enhanced by the presence of the oil and surfactant in the EZVI emulsion.

Water Pollutants/isolation & purification↗
NASA NTRS1972

Visual light flash phenomenon, part C

The Apollo 16 mission provided the opportunity to obtain additional data on the characteristics and frequency of the light flashes and also provided the first opportunity to obtain a direct physical record of incident cosmic ray particles with the Apollo light flash moving emulsion detector (ALFMED). The ALFMED is an electromechanical device that is worn on the head like a helmet and supports cosmic radiation-sensitive emulsions around the head of the test subject. Two light flash observation sessions were conducted during the mission: one during translunar coast and the second during transearth coast. Characteristics of the light flashes observed and reported by the Apollo crew members were generally similar to those reported on previous missions. Analyses of the ALFMED emulsion plates are proceeding as scheduled, although results are not yet available. The ALFMED results should provide conclusive evidence establishing the correlation, if any, between the incident cosmic ray particles and the perception of light flashes as reported by Apollo crew members.

Richard E. Benson↗
NASA NTRS1977

Heterogeneous chemical reactions: Preparation of monodisperse latexes

It is demonstrated that a photoinitiated emulsion polymerization can be carried out to a significant conversion in a SPAR rocket prototype polymerization vessel within the six minutes allowed for the experiment. The percentage of conversion was determined by both dilatometry and gravimetric methods with good agreement. The experimental results lead to the following conclusions: (1) emulsion polymerizations can be carried out to conversions as high as 75%, using a stable micellized styrene-SLS system plus photoinitiator; (2) dilatometry can be used to accurately determine both the rate and conversion of polymerization; (3) thermal expansion due to the light source and heat of reaction is small and can be corrected for if necessary; (4) although seeded emulsion polymerizations are unfavorable in photoinitiation, as opposed to chemical initiation, polymerizations can be carried out to at least 15% conversion using 7940A seed particles, with 0.05% solids; and (5) photoinitiation should be used to initiate polymerization in the SPAR rocket experiments because of the mechanical simplicity of the experiment.

Vanderhoff, J. W.↗
NASA NTRS1976

Photographic image intensification by autoradiography

Images on developed photographic emulsions can be significantly intensified by making the image silver radioactive and exposing a second emulsion to this radiation. Because the print, an autoradiograph, reproduces the original with significant increases in density and contrast, the method can be used to enhance underexposed emulsions and to increase the limits of photographic detection. This paper reports a new, practical chemical method for activating the silver, using thiourea labeled with sulfur-35, a process convenient for use in photographic laboratories. Speed increases of 13 and contrast increases of 18 were achieved with Kodak Plus-X film in this initial phase.

Askins, B. S.↗