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At least 811 records · Page 45

Ice Protection of Turbojet Engines by Inertia Separation of Water II : Single-offset-duct System

Investigation of a single-offset-duct system designed to prevent entrance of water into a turbojet engine was conducted on a half-scale nacelle model. An investigation was made to determine ram-pressure recovery and radial velocity profiles at the compressor section and icing characteristics of such a duct system. At a design inlet velocity of 0.77, the maximum ram-pressure recovery attained with effective water-separating inlet was 77 percent, which is considerably less than attainable with a direct-ram inlet. Continuous heating of the accessory-housing surface would be required for inlets that have a small ice storage space.

NOSE SHAPE - DUCTED BODIES↗

MAGNETIC TRANSPORT ON THE SOLAR ATMOSPHERE BY LAMINAR AND TURBULENT AMBIPOLAR DIFFUSION

The lower solar atmosphere consists of partially ionized turbulent plasmas harboring velocity field, magnetic field, and current density fluctuations. The correlations among these small-scale fluctuations give rise to large-scale flows and magnetic fields which decisively affect all transport processes. The three-fluid system consisting of electrons, ions, and neutral particles supports nonideal effects such as the Hall effect and ambipolar diffusion. Here, we study magnetic transport by the laminar- and turbulent-scale ambipolar diffusion processes using a simple model of the magnetic induction equation. Based on a linear analysis of the induction equation, we perform a one-dimensional numerical simulation to study the laminar ambipolar effect on medium-scale magnetic field structures. The nonlinearity of the laminar ambipolar diffusion creates magnetic structures with sharp gradients in the scale of hundreds of kilometers. We expect that these can be amenable to processes such as magnetic reconnection and energy release therefrom for heating and flaring of the solar plasma. Analyzing the characteristic timescales of these processes, we find that the turbulent diffusion timescale is smaller by several orders of magnitude than the laminar diffusion timescale. The effect of the modeled turbulent ambipolar diffusion on the obtained field structures is briefly discussed.

79 ASTRONOMY AND ASTROPHYSICS↗

Sister Rod Destructive Examinations (FY22) Appendix J: Leaching of High Burnup Used Nuclear Fuel in Deionized Water

The leaching experiment aims to understand the trends in the radiolysis-enhanced dissolution of HBU SNF when exposed to water (e.g., in-reactor or in-pool cladding failures). Specimens from a baseline M5-clad rod and a heat-treated M5 rod were cut from the fractured CIRFT specimens and placed in 100 mL deionized water for a period of 128 days. Both radial and axial sections were cut to provide different surface areas of fuel in contact with the leachate. During the four-month exposure period, aliquot samples of the leachate were analyzed using gamma spectroscopy and inductively coupled plasma - mass spectrometry (ICP-MS). The analysis quantified the amount of fuel leached into the solutions and provided individual isotopic release fractions (of 30+ isotopes) which were compared as a function of time and surface area of the fuel exposed.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Sister Rod Destructive Examinations (FY23): Appendix J: Leaching of High Burnup Used Nuclear Fuel in Deionized Water

The leaching experiment aims to understand the trends in the radiolysis-enhanced dissolution of HBU SNF when exposed to water (e.g., in-reactor or in-pool cladding failures). Specimens from a baseline M5-clad rod and a heat-treated M5 rod were cut from the fractured CIRFT specimens and placed in 100 mL deionized water for a period of 128 days. Both radial and axial sections were cut to provide different surface areas of fuel in contact with the leachate. During the four-month exposure period, aliquot samples of the leachate were analyzed using gamma spectroscopy and inductively coupled plasma - mass spectrometry (ICP-MS). The analysis quantified the amount of fuel leached into the solutions and provided individual isotopic release fractions (of 30+ isotopes) which were compared as a function of time and surface area of the fuel exposed. Consistent with existing literature, the leaching followed a trend in which isotopes of certain elements such as Cs and Mo were among the first species in the matrix to dissolve, and with the highest release rates. This was followed by a gradual matrix dissolution consisting of uranium and other actinides and a slower-than-matrix release from some isotopes, including Ru and Rh. It was also observed that the circumferential samples having less exposed fuel surface area (to begin with) leached more than the axial samples for a majority of the isotopes during the timespan of the study. Previous experiments were conducted by decladding or exposing the pellet-clad surface completely, but the samples used in this study retained the cladding. One possible explanation for the higher leaching rate of the circumferential samples is that the pellet-clad interface, which has a greater density of grain boundaries and defects, may be the most vulnerable area to leaching of fuel in the presence of water.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Preparation of low strategic metal content superalloys

The properties of modified NIMONIC 115 and UDIMET 720 with reduced levels of cobalt were evaluated. Vacuum induction melted and vacuum arc remelted ingots were hot rolled to 3/4 inch diameter bar. Hot workability was evaluated in terms of the ingot rolling behavior and the hot ductility of the as-rolled bar. Variations in workability and bar ductility were correlated to variations in incipient melting temperature and gamma prime solvus, both of which varied with cobalt content. Heat treatments were defined to yield, as far as possible, similar structures from alloy to alloy. At the lowest cobalt levels N-115 workability was severely limited and the alloys could not be worked to bar. It is suggested that incipient melting in combination with heavy grain boundary carbide precipitation reduced ingot workability. Final heat treatment of modified alloys was difficult in the situation where the gamma prime solvus temperature was close to the incipient melting point, indicating that it may not be feasible to fully solution low cobalt alloys to obtain the large grain size required for optimum creep resistance.

Sczerzenie, F. E.↗

Influence of Crucible Materials on High-temperature Properties of Vacuum-melted Nickel-chromium-cobalt Alloy

A study of the effect of induction-vacuum-melting procedure on the high-temperature properties of a titanium-and-aluminum-hardened nickel-base alloy revealed that a major variable was the type of ceramic used as a crucible. Reactions between the melt and magnesia or zirconia crucibles apparently increased high-temperature properties by introducing small amounts of boron or zirconium into the melts. Heats melted in alumina crucibles had relatively low rupture life and ductility at 1,600 F and cracked during hot-working as a result of deriving no boron or zirconium from the crucible.

MATERIALS, PROPERTIES - STRESS-RUPTURE↗

A rat retinal damage model predicts for potential clinical visual disturbances induced by Hsp90 inhibitors

In human trials certain heat shock protein 90 (Hsp90) inhibitors, including 17-DMAG and NVP-AUY922, have caused visual disorders indicative of retinal dysfunction; others such as 17-AAG and ganetespib have not. To understand these safety profile differences we evaluated histopathological changes and exposure profiles of four Hsp90 inhibitors, with or without clinical reports of adverse ocular effects, using a rat retinal model. Retinal morphology, Hsp70 expression (a surrogate marker of Hsp90 inhibition), apoptotic induction and pharmacokinetic drug exposure analysis were examined in rats treated with the ansamycins 17-DMAG and 17-AAG, or with the second-generation compounds NVP-AUY922 and ganetespib. Both 17-DMAG and NVP-AUY922 induced strong yet restricted retinal Hsp70 up-regulation and promoted marked photoreceptor cell death 24 h after the final dose. In contrast, neither 17-AAG nor ganetespib elicited photoreceptor injury. When the relationship between drug distribution and photoreceptor degeneration was examined, 17-DMAG and NVP-AUY922 showed substantial retinal accumulation, with high retina/plasma (R/P) ratios and slow elimination rates, such that 51% of 17-DMAG and 65% of NVP-AUY922 present at 30 min post-injection were retained in the retina 6 h post-dose. For 17-AAG and ganetespib, retinal elimination was rapid (90% and 70% of drugs eliminated from the retina at 6 h, respectively) which correlated with lower R/P ratios. These findings indicate that prolonged inhibition of Hsp90 activity in the eye results in photoreceptor cell death. Moreover, the results suggest that the retina/plasma exposure ratio and retinal elimination rate profiles of Hsp90 inhibitors, irrespective of their chemical class, may predict for ocular toxicity potential. - Highlights: • In human trials some Hsp90 inhibitors cause visual disorders, others do not. • Prolonged inhibition of Hsp90 in the rat eye results in photoreceptor cell death. • Retina/plasma ratio and retinal elimination rate are linked to toxicity potential. • Rat retinotoxic responses to individual Hsp90 inhibitors reflect clinical profiles. • Rodent modeling may be used to assess ocular risks of targeted Hsp90 compounds.

60 APPLIED LIFE SCIENCES↗

Design and implementation of a Thomson parabola for fluence dependent energy-loss measurements at the Neutralized Drift Compression eXperiment

The interaction of ion beams with matter includes the investigation of the basic principles of ion stopping in heated materials. An unsolved question is the effect of different, especially higher, ion beam fluences on ion stopping in solid targets. This is relevant in applications such as in fusion sciences. To address this question, a Thomson parabola was built for the Neutralized Drift Compression eXperiment (NDCX-II) for ion energy-loss measurements at different ion beam fluences. The linear induction accelerator NDCX-II delivers 2 ns short, intense ion pulses, up to several tens of nC/pulse, or 1010-1011 ions, with a peak kinetic energy of ~1.1 MeV and a minimal spot size of 2 mm FWHM. For this particular accelerator, the energy determination with conventional beam diagnostics, for example, time of flight measurements, is imprecise due to the non-trivial longitudinal phase space of the beam. In contrast, a Thomson parabola is well suited to reliably determine the beam energy distribution. The Thomson parabola differentiates charged particles by energy and charge-to-mass ratio, through deflection of charged particles by electric and magnetic fields. During first proof-of-principle experiments, we achieved to reproduce the average initial helium beam energy as predicted by computer simulations with a deviation of only 1.4%25. Successful energy-loss measurements with 1 μm thick silicon nitride foils show the suitability of the accelerator for such experiments. The initial ion energy was determined during a primary measurement without a target, while a second measurement, incorporating the target, was used to determine the transmitted energy. The energy-loss was then determined as the difference between the two energies.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Evidence for electron energization accompanying spontaneous formation of ion acceleration regions in expanding plasmas

We report experiments conducted in an expanding argon plasma generated in the inductive mode of a helicon source in the Hot hELIcon eXperiment–Large Experiment on Instabilities and Anisotropies facility. As the neutral gas pressure increases, the supersonic ion acceleration weakens. Increasing neutral pressure also alters the radial profile of electron temperature, density, and plasma potential upstream of the plasma expansion region. Langmuir probe measurements of the electron energy probability function (EEPF) show that heating of electrons at the plasma edge by RF fields diminishes with increasing gas pressure, yielding a plasma with a centrally peaked electron temperature, and flat potential profiles at higher neutral pressures. For neutral pressures at which ion acceleration regions develop in the expanding plasma plume, EEPFs reveal electrons with two temperature components.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Sister Rod Destructive Examinations (FY2021) Appendix J: Leaching of High Burnup Used Nuclear Fuel in De-ionized Water

As a part of the DOE NE High Burnup Spent Fuel Data Project, Oak Ridge National Laboratory (ORNL) is performing destructive examinations (DEs) of high burnup (HBU) (>45 GWd/MTU) spent nuclear fuel (SNF) rods from the North Anna Nuclear Power Station operated by Dominion Energy. The SNF rods, called sister rods or sibling rods, are all HBU and include four different kinds of fuel rod cladding: standard Zircaloy-4 (Zirc-4), low-tin Zirc-4, ZIRLO, and M5. The leaching experiment was a part of a larger study by Yadukrishnan Sasikumar in defending his doctoral thesis at The Open University, School of Engineering and Innovation [13]. It utilized post-CIRFT Sister Rod test specimens that were slated for disposal. The leaching experiment aims to understand the trends in the radiolytic dissolution of High Burnup Spent Nuclear Fuel (SNF) when exposed to water (e.g., in-reactor or in-pool cladding failures). Specimens from a baseline M5-clad rod and a heat-treated M5 rod were cut from the fractured CIRFT specimens and placed in 100 mL de-ionized water for a period of 128 days. Both radial and axial sections were cut to provide different surface areas of fuel in contact with the leachate. During the four-month exposure period, aliquot samples of the leachate were analyzed gamma spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS). The analysis quantified the amount of fuel leached into the solutions and provided individual isotopic release fractions (of 30+ isotopes) which were compared as a function of time and surface area of fuel exposed.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Butylated hydroxyanisole induces distinct expression patterns of Nrf2 and detoxification enzymes in the liver and small intestine of C57BL/6 mice

Butylated hydroxyanisole (BHA) is widely used as an antioxidant and preservative in food, food packaging and medicines. Its chemopreventive properties are attributing to its ability to activate the transcription factor NF-E2 p45-related factor 2 (Nrf2), which directs central genetic programs of detoxification and protection against oxidative stress. This study was to investigate the histological changes of Nrf2 and its regulated phase II enzymes Nqo1, AKR1B8, and Ho-1 in wild-type (WT) and Nrf2{sup −/−} mice induced by BHA. The mice were given a 200 mg/kg oral dose of BHA daily for three days. Immunohistochemistry revealed that, in the liver from WT mice, BHA increased Nqo1 staining in hepatocytes, predominately in the pericentral region. In contrast, the induction of AKR1B8 appeared mostly in hepatocytes in the periportal region. The basal and inducible Ho-1 was located almost exclusively in Kupffer cells. In the small intestine from WT mice, the inducible expression patterns of Nqo1 and AKR1B8 were nearly identical to that of Nrf2, with more intense staining in the villus than that the crypt. Conversely, Keap1 was more highly expressed in the crypt, where the proliferative cells reside. Our study demonstrates that BHA elicited differential expression patterns of phase II-detoxifying enzymes in the liver and small intestine from WT but not Nrf2{sup −/−} mice, demonstrating a cell type specific response to BHA in vivo. - Highlights: • Histological view of basal and inducible Nrf2 and its targets in vivo • Induction of detoxification enzymes by BHA is cell-type dependent. • BHA induces the expression of HO-1 in Kupffer cells.

60 APPLIED LIFE SCIENCES↗

Numerical Analysis of 2-D and 3-D MHD Flows Relevant to Fusion Applications

Here, the analysis of many fusion applications such as liquid-metal blankets requires application of computational fluid dynamics (CFD) methods for electrically conductive liquids in geometrically complex regions and in the presence of a strong magnetic field. A current state of the art general purpose CFD code allows modeling of the flow in complex geometric regions, with simultaneous conjugated heat transfer analysis in liquid and surrounding solid parts. Together with a magnetohydrodynamics (MHD) capability, the general purpose CFD code will be a valuable tool for the design and optimization of fusion devices. This paper describes an introduction of MHD capability into the general purpose CFD code CFX, part of the ANSYS Workbench. The code was adapted for MHD problems using a magnetic induction approach. CFX allows introduction of user-defined variables using transport or Poisson equations. For MHD adaptation of the code three additional transport equations were introduced for the components of the magnetic field, in addition to the Poisson equation for electric potential. The Lorentz force is included in the momentum transport equation as a source term. Fusion applications usually involve very strong magnetic fields, with values of the Hartmann number of up to tens of thousands. In this situation a system of MHD equations become very rigid with very large source terms and very strong variable gradients. To increase system robustness, special measures were introduced during the iterative convergence process, such as linearization using source coefficient for momentum equations. The MHD implementation in general purpose CFD code was tested against benchmarks, specifically selected for liquid-metal blanket applications. Results of numerical simulations using present implementation closely match analytical solutions for a Hartmann number of up to 1500 for a 2-D laminar flow in the duct of square cross section, with conducting and nonconducting walls. Results for a 3-D test case are also included.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Magnetization, anomalous Barkhausen effect, and core loss of Supermendur under high temperature cycling.

The magnetization and core loss of Supermendur were measured up to 900 C under conditions of slow temperature cycling in vacuum. As a consequence of this heating, the coercivity at 25 C increased from 21 A/m to about 110 A/m. This increase is less than previously reported. A prominent anomalous Barkhausen effect, pinched-in hysteresis loops, and a magnetic viscosity field in excess of 20 A/m were observed in the range of 600 to 700 C. At 850 C, Supermendur had a coercivity of 23 A/m, a saturation induction exceeding 1.5 T, a core loss of 26 W/kg at 400 Hz, and a maximum induction of 1.5 T. Supermendur may be useful for high temperature soft magnetic material applications where some history dependence of properties and instability of minor loops at lower temperatures is acceptable.

Niedra, J. M.↗

Peroxisome proliferator-activated receptor-gamma agonist rosiglitazone attenuates postincisional pain by regulating macrophage polarization

Highlights: Black-Right-Pointing-Pointer Rosiglitazone attenuated postincisional pain. Black-Right-Pointing-Pointer Rosiglitazone alters macrophage polarization to F4/80{sup +}CD206{sup +} M2 macrophages at the incisional sites. Black-Right-Pointing-Pointer Transplantation of rosiglitazone-treated macrophages produced analgesic effects. -- Abstract: Acute inflammation triggered by macrophage infiltration to injured tissue promotes wound repair and may induce pain hypersensitivity. Peroxisome proliferator-activated receptor {gamma} (PPAR){gamma} signaling is known to regulate heterogeneity of macrophages, which are often referred to as classically activated (M1) and alternatively activated (M2) macrophages. M1 macrophages have considerable antimicrobial activity and produce a wide variety of proinflammatory cytokines. In contrast, M2 macrophages are involved in anti-inflammatory and homeostatic functions linked to wound healing and tissue repair. Although it has been suggested that PPAR{gamma} agonists attenuate pain hypersensitivity, the molecular mechanism of macrophage-mediated effects of PPAR{gamma} signaling on pain development has not been explored. In this study, we investigated the link between the phenotype switching of macrophage polarization induced by PPAR{gamma} signaling and the development of acute pain hypersensitivity. Local administration of rosiglitazone significantly ameliorated hypersensitivity to heat and mechanical stimuli, and paw swelling. Consistent with the down-regulation of nuclear factor {kappa}B (NF{kappa}B) phosphorylation by rosiglitazone at the incisional sites, the number of F4/80{sup +}iNOS{sup +} M1 macrophages was decreased whereas numbers of F4/80{sup +}CD206{sup +} M2 macrophages were increased in rosiglitazone-treated incisional sites 24 h after the procedure. In addition, gene induction of anti-inflammatory M2-macrophage-associated markers such as arginase1, FIZZ1 and interleukin (IL)-10 were significantly increased, whereas M1-macrophage-related molecules such as integrin {alpha}X, IL-1{beta}, MIP2{alpha} and leptin were decreased at rosiglitazone-treated incisional sites. Moreover, transplantation of rosiglitazone-treated peritoneal macrophages into the incisional sites significantly attenuated hyperalgesia. We speculate that local administration of rosiglitazone significantly alleviated the development of postincisional pain, possibly through regulating macrophage polarity at the inflamed site. PPAR{gamma} signaling in macrophages may be a potential therapeutic target for the treatment of acute pain development.

60 APPLIED LIFE SCIENCES↗

Alternative RF coupling configurations for H{sup −} ion sources

RF heated sources for negative hydrogen ions both for fusion and accelerators require very high RF powers in order to achieve the required H{sup −} current what poses high demands on the RF generators and the RF circuit. Therefore it is highly desirable to improve the RF efficiency of the sources. This could be achieved by applying different RF coupling concepts than the currently used inductive coupling via a helical antenna, namely Helicon coupling or coupling via a planar ICP antenna enhanced with ferrites. In order to investigate the feasibility of these concepts, two small laboratory experiments have been set up. The PlanICE experiment, where the enhanced inductive coupling is going to be investigated, is currently under assembly. At the CHARLIE experiment systematic measurements concerning Helicon coupling in hydrogen and deuterium are carried out. The investigations show that a prominent feature of Helicon discharges occurs: the so-called low-field peak. This is a local improvement of the coupling efficiency at a magnetic field strength of a few mT which results in an increased electron density and dissociation degree. The full Helicon mode has not been achieved yet due to the limited available RF power and magnetic field strength but it might be sufficient for the application of the coupling concept to ion sources to operate the discharge in the low-field-peak region.

07 ISOTOPE AND RADIATION SOURCES↗

Characterization of Self-Magnetic Pinch (SMP) Radiographic Diode Performance on RITS-6 at Sandia National Laboratories

The goals of an electron beam-driven radiographic source are the focusing of high current at high voltage to a minimal spot size with excellent shot-to-shot reproducibility. The Self-Magnetic Pinch (SMP) diode makes use of such an intense electron beam impinging on a high-atomic weight (tantalum) converter, a counter-streaming ion beam to help minimize the spot size, and operation in a magnetic field-free diode region which further encourages small spot size. Through a series of diode development experiments, output voltages up to 12.5 MV and output currents up to 225 kA have been characterized, with resulting spot sizes below ~ few mm. Scaling studies with parameter variation, such as diode aspect ratio and anode-cathode (A-K) gap variation, give systematic validation to what has heretofore been noted anecdotally by other research groups. While the lack of an imbedded magnetic field helps minimize the SMP spot size, a secondary result may be the generation of beam instabilities which can terminate the radiation pulse. There is anecdotal evidence that in-situ DC heating of the diode region can help stabilize the beam pinch. Clear experimental evidence exists that DC heating/RF cleaning results in better control over the counter-streaming ion population. Expanded use of spatial dose-rate detection is shown to yield new insights into electron beam dynamics in the SMP diode. An attendant study of the SMP diode as a load for an Inductive Voltage Adder (IVA) driver leads to insights into the behavior of the IVA-SMP diode configuration, viewed as a total system, and yields constraints on the overall impedance behavior of the SMP diode load.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Technical Guidance on Use of the Linseis Vertical Dilatometer L75

Linseis vertical Dilatometer L75 thermal expansion equipment is a complete system which can be used for measuring change of the absolute length of a sample, determination of the thermal expansion coefficient (CTE), shrinkage, and sintering. The 238 Pu Supply Program is interested in re-establishing the capability to determine CTE and measuring the change of the absolute length of various 237 Np Al/cermet samples during heating. The change in length of the measured sample is recorded using a highly sensitive Linear Variable Differential Transformer (LVDT). The dilatometer is user-friendly and simple to operate which will allow technicians to be trained easily on its use. This equipment was designed to be used specifically for ceramics. It has a highly vacuum tight push rod dilatometer, a high-resolution inductive transducer using innovative and comprehensive temperature controls which provide excellent performance as a measurement system yielding high accuracy, reproducibility, and long-term stability.

07 ISOTOPE AND RADIATION SOURCES↗

Radiological Characterization of Uranium Decay Products in LEU U-10Mo Before and After Heat Treatment

Fuel for the U.S. high-performance research reactor fleet is undergoing significant development as the United States moves away from using highly enriched uranium dispersion fuels. The proposed fuel is a high-density, low-enriched uranium (LEU, 19.75 wt% U 235) alloyed with ten weight percent molybdenum fuel (known as LEU U 10Mo). The LEU U 10Mo fuel samples studied in this report were made by down-blending highly enriched uranium with a master alloy, which is cast from molybdenum rods and depleted uranium, via vacuum induction melting and then casting.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗