SEARCH · Search NASA

Results for “iodine”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10

All sources NASA NTRS DOE OSTI

NASA NTRS1990

Planar measurement of flow field parameters in a nonreacting supersonic combustor using laser-induced iodine fluorescence

A nonintrusive optical technique, laser-induced iodine fluorescence, has been used to obtain planar measurements of flow field parameters in the supersonic mixing flow field of a nonreacting supersonic combustor. The combustor design used in this work was configured with staged transverse sonic injection behind a rearward-facing step into a Mach 2.07 free stream. A set of spatially resolved measurements of temperature and injectant mole fraction has been generated. These measurements provide an extensive and accurate experimental data set required for the validation of computational fluid dynamic codes developed for the calculation of highly three-dimensional combustor flow fields.

Hartfield, Roy J., Jr.↗

NASA NTRS1990

Experimental investigation of a supersonic swept ramp injector using laser-induced iodine fluorescence

Planar measurements of injectant mole fraction and temperature have been conducted in a nonreacting supersonic combustor configured with underexpanded injection in the base of a swept ramp. The temperature measurements were conducted with a Mach 2 test section inlet in streamwise planes perpendicular to the test section wall on which the ramp was mounted. Injection concentration measurements, conducted in cross flow planes with both Mach 2 and Mach 2.9 free stream conditions, dramatically illustrate the domination of the mixing process by streamwise vorticity generated by the ramp. These measurements, conducted using a nonintrusive optical technique (laser-induced iodine fluorescence), provide an accurate and extensive experimental data base for the validation of computation fluid dynamic codes for the calculation of highly three-dimensional supersonic combustor flow fields.

Hartfield, Roy J.↗

NASA NTRS1990

Are there interactions of iodine and sulfur species in marine air photochemistry?

The effects of dimethyl sulfide (DMS) and methyl iodide (MI) emissions are analyzed using a two-dimensional photochemical model of a marine tropical tropospheric synoptic system. The model traces the atmospheric transformation cycles of the emissions to aerosols. The study is focused on remote tropical ocean regions and includes simulations of the spatial and diurnal variations of various iodine and sulfur species, and the species OH, HO2, and H2O2. One line of analysis leads to the conclusion that the reaction IO + DMS yields DMSO + I may play a significant role in destroying DMS if it proceeds at the published fast rate. Alternative lines of analyses are presented.

Chatfield, Robert B.↗

NASA NTRS1991

Viscosity of high-temperature iodine

The viscosity coefficient of iodine in the temperature range 500 - 3000 K is calculated. Because of the low dissociation energy of the I2 molecules, the dissociation degree of the gas increases quickly with temperature, and I + I2 and I + I collisions must be taken into account in calculation of viscosity at temperatures greater than 1000 deg. Several possible channels for atom-atom interaction are considered, and the resulting collision integrals are averaged over all the important channels. It is also shown that the rigid-sphere model is inaccurate in predictions of the viscosity.

Kang, Steve H.↗

NASA NTRS1992

A unified planar measurement technique for compressible flows using laser-induced iodine fluorescence

A unified laser-induced fluorescence technique for conducting planar measurements of temperature, pressure and velocity in nonreacting, highly compressible flows has been developed, validated and demonstrated. Planar fluorescence from iodine, seeded into air, was induced by an argon-ion laser and collected using a liquid-nitrogen cooled CCD camera. In the measurement technique, temperature is determined from the fluorescence induced with the laser operated broad band. Pressure and velocity are determined from the shape and position of the fluorescence excitation spectrum which is measured with the laser operated narrow band. The measurement approach described herein provides a means of obtaining accurate, spatially-complete maps of the primary flow field parameters in a wide variety of cold supersonic and transonic flows.

Hartfield, Roy J., Jr.↗

NASA NTRS1990

Real-time quality assurance testing using photonic techniques: Application to iodine water system

A feasibility study of the use of inspection systems incorporating photonic sensors and multivariate analyses to provide an instrumentation system that in real-time assures quality and that the system in control has been conducted. A system is in control when the near future of the product quality is predictable. Off-line chemical analyses can be used for a chemical process when slow kinetics allows time to take a sample to the laboratory and the system provides a recovery mechanism that returns the system to statistical control without intervention of the operator. The objective for this study has been the implementation of do-it-right-the-first-time and just-in-time philosophies. The Environment Control and Life Support Systems (ECLSS) water reclamation system that adds iodine for biocidal control is an ideal candidate for the study and implementation of do-it-right-the-first-time technologies.

Arendale, W. F.↗

NASA NTRS1993

Computer-controlled multi-parameter mapping of 3D compressible flowfields using planar laser-induced iodine fluorescence

A computer-controlled technique, using planar laser-induced iodine fluorescence, for measuring complex compressible flowfields is presented. A new laser permits the use of a planar two-line temperature technique so that all parameters can be measured with the laser operated narrowband. Pressure and temperature measurements in a step flowfield show agreement within 10 percent of a CFD model except in regions close to walls. Deviation of near wall temperature measurements from the model was decreased from 21 percent to 12 percent compared to broadband planar temperature measurements. Computer-control of the experiment has been implemented, except for the frequency tuning of the laser. Image data storage and processing has been improved by integrating a workstation into the experimental setup reducing the data reduction time by a factor of 50.

Donohue, James M.↗

NASA NTRS1992

Directly solar-pumped iodine laser for beamed power transmission in space

A new approach for development of a 50-kW directly solar-pumped iodine laser (DSPIL) system as a space-based power station was made using a confocal unstable resonator (CUR). The CUR-based DSPIL has advantages, such as performance enhancement, reduction of total mass, and simplicity which alleviates the complexities inherent in the previous system, master oscillator/power amplifier (MOPA) configurations. In this design, a single CUR-based DSPIL with 50-kW output power was defined and compared to the MOPA-based DSPIL. Integration of multiple modules for power requirements more than 50-kW is physically and structurally a sound approach as compared to building a single large system. An integrated system of multiple modules can respond to various mission power requirements by combining and aiming the coherent beams at the user's receiver.

Choi, S. H.↗

NASA NTRS1986

Solar-pumped photodissociation iodine laser

The scientific feasibility of a solar-pumped iodine photodissociation laser for space applications is under investigation. Recently, a 2-W CW output for more than one hour was achieved using n-C3F7I vapor as the laser material and a vortex-stabilized argon arc as the light source.

Lee, J. H.↗

NASA NTRS1992

Amplified spontaneous emission in solar-pumped iodine laser

The amplified spontaneous emission (ASE) from a long pulse, solar-simulating radiation pumped iodine laser amplifier is studied. The ASE threshold pump intensity is almost proportional to the inverse of the laser gain length when the gas pressure is constant in the laser tube.

Cho, Yong S.↗

NASA NTRS1993

A method to remove intercalates from bromine and iodine intercalated carbon fibers

Upon exposure to room-temperature fluorine, intercalated carbon fibers (containing either bromine alone or iodine and bromine together) become heavier and less stable. For Amoco P-100 graphitized carbon fibers which were intercalated with 18 percent bromine by weight, 1 hr of fluorine exposure results in a large weight increase, but causes only a small decrease in thermal stability. More than l hr of fluorine exposure time results in small additional increases in fiber weight, but significant further decreases in fiber thermal stability. Such phenomena do not occur if the fluorine exposure is at 250 C. These observations suggest the mechanism that at room temperature, fluorine is absorbed quickly by the intercalated fibers and intercalated slowly into the fibers. Most of the original intercalates are replaced by fluorine in the process of fluorine intercalation. Under an inert environment, the bromine intercalated fibers are much more thermally stable. After 800 C vacuum heating for two weeks, the brominated fibers lost about 45 percent of their bromine, and their resistivity increased from 64 omega-cm to a range of 95 to 170 micro omega-cm. This is still much lower than the 300 micro omega-cm value for pristine P-100. For practical purposes, in order to preserve their thermal stability, brominated fibers need to be protected from exposure to fluorine at room temperature, or to any intercalate at a temperature where, upon direct contact to graphite, an intercalation compound can easily be formed.

Hung, Ching-Cheh↗

NASA NTRS1995

Room-Temperature Fluorine-Induced Decrease in the Stability of Bromine and Iodine Intercalated Carbon Fibers

Upon exposure to room-temperature fluorine, intercalated carbon fibers (containing either bromine alone or iodine and bromine together) become heavier and less stable. For Amoco P-100 graphitized carbon fibers, which were intercalated with 18 wt percent bromine, 1 hour of fluorine exposure resulted in a large weight increase but caused only a small decrease in thermal stability. An additional 89 hours of fluorine exposure time resulted in small additional increases in fiber weight, but significant further decreases in fiber thermal stability. Such phenomena of weight increase and stability decrease do not occur if the intercalated fibers are exposed to 250 C fluorine. These observations suggest that, at room temperature, fluorine is absorbed quickly by the intercalated fibers and is intercalated slowly into the fibers. Most of the original intercalates are replaced by fluorine in the process of fluorine intercalation. In an inert environment, the bromine intercalated fibers are much more thermally stable. After 800 C vacuum heating for 2 weeks, the brominated fibers lost about 45% of their bromine, and their resistivity increased from 64 mu(Omega)-cm to a range of 95-170 mu(Omega)-cm. This is still much lower than the value of 300 mu(Omega)-cm for pristine P-100. For practical purposes, to preserve their thermal stability, brominated fibers need to be protected from exposure to fluorine at room temperature or to any intercalate at a temperature where, upon direct contact with graphite, an intercalation compound can easily be formed.

Hung, Ching-Cheh↗

NASA NTRS1995

Comparison of the Effects of Iodine and Iodide on Thyroid Function in Humans

The present experiment in humans failed to confirm the differential effect of I(sub 2) on maintenance of serum T(sub 4) concentrations relative to the effects of I(-) that was observed in prior experiments in rats. The reaction of I(sub 2) with metabolites of thyroid hormones in the intestine that appears responsible for this effect in rats probably also exists at some level in humans. The present results suggest that the concentrations of such metabolites in the human intestinal tract are too small to significantly affect circulating concentration of T(sub 4). However, based on the elevations in TSH, there should be some concern over the potential impacts of chronic consumption of iodine in drinking water.

Robison, Linda M.↗

NASA NTRS1995

Collisional Shift and Broadening of Iodine Spectral Lines in Air Near 543 nm

The collisional processes that influence the absorption of monochromatic light by iodine in air have been investigated. Measurements were made in both a static cell and an underexpanded jet flow over the range of properties encountered in typical compressible-flow aerodynamic applications. Experimentally measured values of the collisional shift and broadening coefficients were 0.058 +/- 0.004 and 0.53 +/- 0.010 GHz K(exp 0.7)/torr, respectively. The measured shift value showed reasonable agreement with theoretical calculations based on Lindholm-Foley collisional theory for a simple dispersive potential. The measured collisional broadening showed less favorable agreement with the calculated value.

Fletcher, D. G.↗

NASA NTRS1997

A 50-kW Module Power Station of Directly Solar-Pumped Iodine Laser

The conceptual design of a 50 kW Directly Solar-Pumped Iodine Laser (DSPIL) module was developed for a space-based power station which transmits its coherent-beam power to users such as the moon, Martian rovers, or other satellites with large (greater than 25 kW) electric power requirements. Integration of multiple modules would provide an amount of power that exceeds the power of a single module by combining and directing the coherent beams to the user's receiver. The model developed for the DSPIL system conservatively predicts the laser output power (50 kW) that appears much less than the laser output (93 kW) obtained from the gain volume ratio extrapolation of experimental data. The difference in laser outputs may be attributed to reflector configurations adopted in both design and experiment. Even though the photon absorption by multiple reflections in experimental cavity setup was more efficient, the maximum secondary absorption amounts to be only 24.7 percent of the primary. However, the gain volume ratio shows 86 percent more power output than theoretical estimation that is roughly 60 percent more than the contribution by the secondary absorption. Such a difference indicates that the theoretical model adopted in the study underestimates the overall performance of the DSPIL. This fact may tolerate more flexible and radical selection of design parameters than used in this design study. The design achieves an overall specific power of approximately 5 W/kg and total mass of 10 metric tons.

Choi, S. H.↗

NASA NTRS2000

The Rotational Spectrum of Iodine Dioxide, OIO

The rotational spectra of OIO in its ground vibrational and first excited bending states have been observed for the first time. OIO was formed initially from the products of a microwave discharge in O2 passing over molecular iodine and later with greater yield in a DC discharge through a mixture of O2 and I2 vapor. OIO is an asymmetric prolate rotor (kappa = -0.690) with a (sup 2)B(sub 1) electronic ground state. Over 550 ground state transitions and over 160 transitions of the excited bending state have been included in the fits. The resulting parameters are well determined and will be compared to those recently published for OBrO and OClO. These will be interpreted in terms of the molecular geometry, harmonic force field, and electronic structure.

Miller, Charles E.↗

NASA NTRS1992

Evidence of thyroxine formation following iodine administration in Sprague-Dawley rats

Iodine (I2) has been proposed to be used as a water disinfectant on the manned space station. Previous work has shown that subchronic administration of I2 to Sprague-Dawley rats in drinking water significantly increases plasma thyroxine/triiodothyronine (T4/T3) levels. This is not observed with iodide (I-) treatment. The present study addresses the possibility that I2 reacts with deiodinated T4 metabolites in the gastrointestinal tract to resynthesize T4. Incubation of diiodothyronine (T2), T3, or reverse T3 with I2 in phosphate-buffered saline resulted in the formation of T4 as measured by radioimmunoassay. Washes from the initial segments of the small intestine of the rat show that substrates are present that react with I2 to produce T4. Single oral doses of I2 to rats produced significant dose-related increases in serum T4 and decreases in T3 concentrations after 2 h. Administration of an equivalent dose of I- did not alter significantly plasma T4 concentrations. Higher concentrations of a radioactive substance that bound a T4-specific antibody are present in plasma of animals treated with 125I2 compared to 125I-. These data support the hypothesis that I2 reacts with metabolites of thyroid hormone in the gastrointestinal tract to resynthesize T4 and elevate its levels in blood.

NASA Discipline Environmental Health↗

NASA NTRS2008

Safety Review Panel (SRP) Special Topic Presentation on the Iodine Compatible Water Container (ICWC)

This viewgraph presentation reviews the safety requirements for the Iodine Compatible Water Container (ICWC). The topics include: 1) ICWC Team; 2) Purpose of presentation; 3) Background/Description of ICWC System; 4) Current status of ICWC Project; 5) HTV launch NCR Processing; 6) Tox 1 containment NCR processing; and 7) ISS on-orbit failure propagation and fault tolerance NCR processing.

Thomas, Evan A.↗