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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.

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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Direct solar-pumped iodine laser amplifier

A XeCl laser pumped iodine laser oscillator was developed which will be incorporated into the Master Oscillator Power Amplifier (MOPA) system. The developed XeCl laser produces output energy of about 60 mJ per pulse. The pulse duration was about 10 nsec. The kinetic model for the solar-pumped laser was refined and the algorithm for the calculation of a set of rate equations was improved to increase the accuracy and the efficiency of the calculation. The improved algorithm was applied to explain the existing experimental data taken from a flashlamp pumped iodine laser for three kinds of lasants, i-C3F7I, n-C4F9I, and t-C4F9I. Various solid laser materials were evaluated for solar-pumping. The materials studied were Nd:YAG, Nd:YLF, and Cr:Nd:GSGG crystals. The slope efficiency of 0.17 percent was measured for the Nd:YLF near the threshold pump intensity which was 211 solar constants (29W/sq cm). The threshold pump intensity of the Nd:YAG was measured to be 236 solar constants (32W/sq cm) and the near-threshold slope efficiency was 0.12 percent. True CW laser operation of Cr:Nd:GSGG was possible only at pump intensities less than or equal to 1,500 solar constants (203 W/sq cm). This fact was attributed to the high thermal focusing effect of the Cr:Nd:GSGG rod.

Han, Kwang S.↗
NASA NTRS1988

Carrier phases for iodine in the Allende meteorite and their associated Xe-129(r)/I-127 ratios - A laser microprobe study

This paper presents the results of a study of the carrier phases of iodine in the Allende meteorite and their associated Xe-129(r)/I-127 ratios, obtained using a new high-sensitivity low-blank mass spectrometer coupled with a low-blank laser extraction system. Two types of experiments were performed: a survey of the Xe-129(r) amounts in unirradiated specimens of fine-grained assemblages and individual coarse mineral grains, and a study of the relationship between chlorine and iodine in irradiated samples of the inclusions, in which the Xe-129(r)/I-127 ratios were determined for various minerals. As a by-product of these measurements, the Ar-40/Ar-39 ages were obtained along with some results on trapped Xe components. A schematic diagram of the new mass spectrometer system is included.

Kirschbaum, C.↗
NASA NTRS1989

XeCl laser pumped iodine laser using t-C4F9I

An iodine photodissociation laser using t-C4F9I as the active material was pumped by an XeCl laser. An iodine laser output energy of 3 mJ with pulse duration of 25 ns was obtained when the pumping pulse energy was 80 mJ, the iodide pressure was 70 torr, and the reflectance of the output mirror was 85 percent. The high pumping efficiency and low threshold pump power achieved in this experiment are attributable to the high absorption cross section at the pump laser wavelength (308 nm) of the iodide used.

Hwang, In Heon↗
NASA NTRS1991

Planar temperature measurement in compressible flows using laser-induced iodine fluorescence

A laser-induced iodine fluorescence technique that is suitable for the planar measurement of temperature in cold nonreacting compressible air flows is investigated analytically and demonstrated in a known flow field. The technique is based on the temperature dependence of the broadband fluorescence from iodine excited by the 514-nm line of an argon-ion laser. Temperatures ranging from 165 to 245 K were measured in the calibration flow field. This technique makes complete, spatially resolved surveys of temperature practical in highly three-dimensional, low-temperature compressible flows.

Hartfield, Roy J., Jr.↗
NASA NTRS1991

Early outgassing of Mars supported by differential water solubility of iodine and xenon

The Martian atmosphere has a high X-129/Xe-132 ratio compared to the Martian mantle. As Xe-129 is the daughter product of the extinct nuclide I-129, a means of fractionating iodine from xenon early in Martian history appears necessary to account for the X-129/Xe-132 ratios of its known reservoirs. A model is presented here to account for the Marian xenon data which relies on the very different solubilities of xenon and iodine in water to fractionate them after outgassing. Atmospheric xenon is lost by impact erosion during heavy bombardment, followed by release of Xe-129 produced from I-129 decay in the crust.

Musselwhite, Donald S.↗
NASA NTRS1991

Thyroid effects of iodine and iodide in potable water

Experiments are reviewed which examine the comparative toxicological effects of iodide (I) and iodine (I2) when used to disinfect drinking water. References are made to a subchronic study in rats, a comparison of the distribution of radiolabeled I and I2, and a demonstration of thyroxine formation in the gastrointestinal tract. The results of the study of the rats are examined in detail; the findings show that I and I2 have opposite effects on the concentrations of thyroid hormones in blood. Iodide slightly decreases circulating thyroxine, while I2 significantly increases the thyroxine concentrations, decreases triiodothyronine levels, and does not change the weight of the thyroid gland. The related effects of I2 ingestion are set forth in detail and are shown to be unique to I2 contamination. Iodine can counteract the effects of iodide and should therefore be used as a disinfectant in drinking water.

Bull, Richard J.↗
NASA NTRS1994

Regenerable Iodine Water-Disinfection System

Iodinated resin bed for disinfecting water regenerated to extend useful life. Water flows through regeneration bed of crystalline iodine during regeneration. At other times, flow diverted around regeneration bed. Although regeneration cycle manually controlled readily automated to start and stop according to signals from concentration sensors. Further benefit of regeneration is bed provides highly concentrated biocide source when needed. Concentrated biocide used to superiodinate system after contamination from routine maintenance or unexpected introduction of large concentration of microbes.

Sauer, Richard L.↗
NASA NTRS1994

Regenerable Iodine Water-Disinfection System

Iodinated resin bed for disinfecting water regenerated to extend its useful life. Water flows through regeneration bed of crystalline iodine during regeneration. At other times, flow diverted around regeneration bed. Although regeneration cycle was manually controlled in demonstration, readily automated to start and stop according to signals and stop according to signals from concentration sensors. Further benefit of regeneration is that regeneration bed provides highly concentrated biocide source (200 mg/L) when needed. Concentrated biocide used to superiodinate system after contamination from routine maintenance or unexpected introduction of large concentration of microbes.

Sauer, Richard L.↗
NASA NTRS1999

Iodine-Xenon Dating: Sensitive Chronometer for Reprocessing in the Primitive Solar System

The I-Xe chronometer is based upon decay of I-129 to Xe-129 in the early Solar System. Recent comparison of I-Xe system in individual mineral separates from twelve different meteorites with independent Pb-Pb data has demonstrated that I-Xe clock is a reliable sensitive chronometer when applied to a single mineral system. Since most iodine hosts are secondary minerals, the I-Xe clock generally records post-formational processing, providing the information on early meteorite evolution. Absolute I-Xe ages can be found by normalization using the measured I-Xe and Pb-Pb ages of Acapulco phosphate (4.557 plus or minus 0.002 Ga). Absolute ages for the I-Xe internal standards Shallow water and Bjurbole, 4.566 plus or minus 0.002 Ga and 4.565 plus or minus 0.003 Ga, respectively, provide absolute I-Xe ages for all other samples. The I-Xe age of bulk meteorite is meaningful and interpretable only when the carrier of primordial iodine is a major mineral phase (e. g., enstatite chondrites). Using the "monomineral" approach, separated phases from the Richardton H5 chondrite provide a case history of post-formational alteration in this object. This work applies the I-Xe chronometer to determine the times of reprocessing of selected minerals in single meteorite types. A preliminary account of this work was recently reported. Additional information is contained in the original extended abstract.

Pravdivtseva, O. V.↗
NASA NTRS2012

Air Density Measurements in a Mach 10 Wake Using Iodine Cordes Bands

An exploratory study designed to examine the viability of making air density measurements in a Mach 10 flow using laser-induced fluorescence of the iodine Cordes bands is presented. Experiments are performed in the NASA Langley Research Center 31 in. Mach 10 air wind tunnel in the hypersonic near wake of a multipurpose crew vehicle model. To introduce iodine into the wake, a 0.5% iodine/nitrogen mixture is seeded using a pressure tap at the rear of the model. Air density was measured at 56 points along a 7 mm line and three stagnation pressures of 6.21, 8.62, and 10.0 MPa (900, 1250, and 1450 psi). Average results over time and space show rho(sub wake)/rho(sub freestream) of 0.145 plus or minus 0.010, independent of freestream air density. Average off-body results over time and space agree to better than 7.5% with computed densities from onbody pressure measurements. Densities measured during a single 60 s run at 10.0 MPa are time-dependent and steadily decrease by 15%. This decrease is attributed to model forebody heating by the flow.

Balla, Robert J.↗
NASA NTRS2013

Iodine Tagging Velocimetry and Mechanism in the Hypersonic Near Wake of a MultiPurpose Crew Vehicle

This study demonstrates a new molecular tagging velocimetry (MTV) method for velocity measurements of high speed flow. It demonstrates offbody Iodine Tagging Velocimetry (ITV) in the hypersonic near wake of a MultiPurpose Crew Vehicle (MPCV) model. Experiments are performed in the NASA-Langley 31-inch Mach 10 air wind tunnel. A 0.5% I2 / N2 mixture is seeded on the leeward backshell of the model using a pressure tap. I2 laser-induced fluorescence is excited along a 5.5 mm line using an ArF excimer laser near 193 nm. Results indicate I2 absorbs at least 2 photons to produce iodine ions and electrons. These recombine as the tagged region is displaced downstream to produce I (2P3/2) whose emission is monitored at 206 nm. Results at P0 = 2.41 MPa (350 psi), T0 = 990K, and 10 micro-sec transit times produce velocities from 630-820 m/sec across the I2 seeded jet at a distance of 38.2 mm (25.5 jet diameters) downstream from the jet orifice. Maximum wake jet velocities near the shear layer are 59% of freestream velocity.

Balla, R. Jeffrey↗
NASA NTRS2015

The Iodine Satellite (iSat) Project Development Towards Critical Design Review

Despite the prevalence of small satellites in recent years, the systems flown to date have very limited propulsion capability. SmallSats are typically secondary payloads and have significant constraints for volume, mass, and power in addition to limitations on the use of hazardous propellants or stored energy. These constraints limit the options for SmallSat maneuverability. NASA's Space Technology Mission Directorate approved the iodine Satellite flight project for a rapid demonstration of iodine Hall thruster technology in a 12U (cubesat units) configuration under the Small Spacecraft Technology Program. The mission is a partnership between NASA MSFC, NASA GRC, and Busek Co, Inc., with the Air Force supporting the propulsion technology maturation. The team is working towards the critical design review in the final design and fabrication phase of the project. The current design shows positive technical performance margins in all areas. The iSat project is planned for launch readiness in the spring of 2017.

Dankanich, John W.↗
NASA NTRS2018

Iodine Satellite Propellant Feed Clog-Clearing Demonstration Testing

Experiments are conducted to quantify the formation and clearing of iodine clogs in an iodine feed system. Deposits in the low-pressure portion of the system near the exit to vacuum appear to be relatively small in extent and incomplete in blocking the flow, and they are relatively easy to remove with the re-application of heating, disappearing in minutes. Clogs forming upstream, nearer to the higher-pressure propellant tank, appear to completely block the flow, are much larger in spatial extent, and form much more rapidly than the low-pressure blockages. Significantly more effort is required to remove upstream deposits.

Polzin, K. A.↗
NASA NTRSDate not supplied

Evaluation of Iodine and Silver as Biocides for Potable Water in Human Missions beyond Low Earth Orbit

Chemical biocides play an important role in potable water storage and distribution systems. They provide protection against microbial growth that can negatively impact efficient water transport and crew health. Molecular iodine and ionic silver have been used on the International Space Station for decades. Future orbiting and surface habitats will have potable water systems that will require reliable potable water storage and challenging transport schemes during daily operations with potentially lengthy and repeated periods of non-use. Based on a review of literature, experimental data, and flight data this paper categorizes the advantages and disadvantages of the two heritage biocides on ISS: iodine and silver. The history of biocide practices on ISS is compared to requirements of future human missions beyond low Earth Orbit. The upstream water quality supply and downstream water uses are defined with respect to the two biocides. The methods of injection and removal of the two biocides are compared for a range of downstream water uses including drinking water, hygiene water, technical water, oxygen generation water, and extravehicular activity water. The paper provides mission planners with a technical and engineering assessment of the two biocides and identifies gaps in knowledge and on-orbit experiences.

Dean Muirhead↗
DOE OSTI2024

Iodine Modulates the MACl‐Assisted Growth of FAPbI 3 for High Efficiency Perovskite Solar Cells

The preferential growth of α-phase formamidinium perovskite (α-FAPbI 3 ) at low temperatures can be achieved with the incorporation of chloride-based additives, with methylammonium chloride (MACl) being the most common example. However, compared to other less-volatile chloride additives, MACl only remains in the growing perovskite film for a short time before evaporating during annealing, primarily influencing the early stages of film formation. In addition, evaporation of MACl as methylamine (MA 0 ) and HCl can introduce a side reaction between MA 0 and formamidinium (FA), undermining the compositional purity and phase stability of α-FAPbI 3 . In this study, it is demonstrated that addition of iodine (I 2 ) into the FAPbI 3 precursor solution containing MACl suppresses the MA-FA side reaction during annealing. Additionally, MACl evaporation is delayed owing to strong interaction with triiodide. The added I 2 facilitates spontaneous growth of α-FAPbI 3 prior to annealing, with an improved bottom morphology due to the formation of fewer byproducts. Perovskite solar cells derived from an I 2 -incorporated solution deliver a champion power conversion efficiency of 25.2% that is attributed to suppressed non-radiative recombination.

14 SOLAR ENERGY↗
DOE OSTI2020

Developing a system for in vivo imaging of maize roots containing iodinated contrast media in soil using synchrotron XCT and XRF

We sought to develop a novel experimental system which enabled application of iodinated contrast media to in vivo plant roots intact in soil and was compatible with time-resolved synchrotron X-ray computed tomography imaging. The system was developed to overcome issues of low contrast to noise within X-ray computed tomography images of plant roots and soil environments, the latter of which can complicate image processing and result in the loss of anatomical information. To demonstrate the efficacy of the system we employ the novel use of both synchrotron X-ray computed tomography and synchrotron X-ray fluorescence mapping to capture the translocation of the contrast media through root vasculature into the leaves. With the application of contrast media we identify fluid flow in root vasculature and visualise anatomical features, which are otherwise often only observable in ex vivo microscopy, including: the xylem, metaxylem, pith, fibres in aerenchyma and leaf venation. We are also able to observe interactions between aerenchyma cross sectional area and solute transport in the root vasculature with depth. Our novel system was capable of successfully delivering sufficient contrast media into root and leaf tissues such that anatomical features could be visualised and internal fluid transport observed. We propose that our system could be used in future to study internal plant transport mechanisms and parameterise models for fluid flow in plants.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Cs 3 Bi 2 I 9 -hydroxyapatite composite waste forms for cesium and iodine immobilization

Perovskite-based ceramic composites were developed as potential waste form materials for immobilizing cesium (Cs) and iodine (I) with high waste loadings and chemical durability. The perovskite Cs 3 Bi 2 I 9 has high Cs (22 wt%) and I (58 wt%) content, and thus can be used as a potential host phase to immobilize these critical radionuclides. In this work, the perovskite Cs 3 Bi 2 I 9 phase was synthesized by a cost effective solution-based approach, and was embedded into a highly durable hydroxyapatite matrix by spark plasma sintering to form dense ceramic composite waste forms. The chemical durabilities of the monolithic Cs 3 Bi 2 I 9 and Cs 3 Bi 2 I 9 -hydroxyapatite composite pellets were investigated by static and semi-dynamic leaching tests, respectively. Cs and I are incongruently released from the matrix for both pure Cs 3 Bi 2 I 9 and composite structures. The normalized Cs release rate is faster than that of I, which can be explained by the difference in the strengths between Cs-I and Bi-I bonds as well as the formation of insoluble micrometer-sized BiOI precipitates. The activation energies of elemental releases based on dissolution and diffusion-controlled mechanisms are determined with significantly higher energy barriers for dissolution from the composite versus that of the monolithic Cs 3 Bi 2 I 9 . The ceramic-based composite waste forms exhibit excellent chemical durabilities and waste loadings, commensurate with the state-of-the-art glass-bonded perovskite composites for I and Cs immobilization.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗