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DOE OSTI2019

AP-105 Melter Offgas Condensate and EMF Evaporator Concentrate Raman and LIBS Qualitative Evaluation for the use of In-Line Monitoring (Rev. 0)

The Pacific Northwest National Laboratory (PNNL) was tasked to perform Raman spectroscopy and laser induced breakdown spectroscopy (LIBS) testing on the melter off-gas condensate generated during low-activity waste process testing of a sample from Hanford Site tank AP-105 and/or evaporate from evaporation of the condensate. This was a proof-of-principle demonstration that Raman spectroscopy and LIBS have the potential to be used as analytical tools for in-line process analysis of key aqueous phase analytes in radioactive process streams associated with the Hanford Waste Treatment and Immobilization Plant. The work completed under this project complements work completed for WRPS with the development of in-line monitoring systems to characterize and quantify constituents of tank waste following Cs removal and filtration. The WRPS work is currently limited to Raman sensors and utilizes chemometric models for quantification of several anionic species in the sample system. It should be noted that while this approach can be applied to off-gas condensate streams, new chemometric models are needed to accurately quantify analytes under off-gas condensate conditions. The work completed under this project makes timely use of available samples and equipment at PNNL. The project utilized the opportunity to collect off-gas samples from planned AP-105 processing work and included the direct condensate and the evaporate from the DFLAW Radioactive Waste Test Platform. Samples were characterized by instruments already in place at PNNL including a Raman spectrometer optimized for in-line monitoring of flowing and stationary samples as well as a LIBS instrument, which was optimized for static liquid droplet analysis. The ultimate objective was to determine if these techniques could be used to qualitatively characterize analytes present within the off-gas samples. The testing confirmed the use of the Raman as an in-line monitoring system was able to qualitatively observe NO 3 - , NO 2 - , aluminum (as aluminate, Al(OH) 4 - ), SO 4 2- , CrO 4 2- , CO 3 2- , and PO 4 3- in the AP-105 melter feed evaporator condensate samples. The testing also confirmed LIBS as a potential useful technique for in-line monitoring, able to qualitatively detect Na, N, Al, and tentatively Cr and Cl in a simulant stock evaporate solution.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2021

Methods and systems for detection of man-in-the-middle attacks for SCADA communication networks and applications of same

A system for detecting MITM for SCADA communication networks includes secure substation-substation communication links for providing secure and reliable paths to exchange OT data between substations for OT data consistency check; a SIB in each substation for sampling CT and PT measurements to calculate voltage magnitude and phase angle thereof; a S&C server in each substation coupled to the SIB for receiving the voltage magnitude and phase angle from the SIB and obtaining a packet carrying active power flow in transmission lines between two substations and a time stamp; an IDS server placed in a SCADA center for collecting the packet of each substation sent by the S&C server; analyzing the received packet from every adjacent substation; inspecting the payload of the received packet; and triggering an intrusion alarm to a SCADA operator when the power flow is not the same as the payload of the packets.

McCann, Roy A.↗

NASA NTRS1982

Observations of mass accretion in binary stars

Results from high resolution observations of eight close binary stars (TX UMa, U CrB, CX Dra, TT Hya, AU Mon, KX And, HR 2142, and phi Per) are presented. Variable absorption lines, indicative of mass flow, are observed in all systems expect phi Per. Emission lines are seen in KX And and phi Per. Variable high ionization features (NV, SiIV, and CIV) are seen in TX UMa, UCrB, CX Dra, and AU Mon. The observations are modeled using the calculations of Lubow and Shu.

Polidan, R. S.↗

NASA NTRS1995

Simultaneous prenoon and postnoon observations of three field-aligned current systems from Viking and DMSP-F7

The spatial structure of dayside large-scale field-aligned current (FAC) systems is examined by using Viking and Defense Meteorological Satellite Program-F7 (DMSP-F7) data. We focus on four events in which the satellites simultaneously observed postnoon and prenoon three FAC systems: the region 2, the region 1, and the mantle (referred to as midday region O) systems, from equatorward to poleward. These events provide the most solid evidence to date that the midday region O system is a separate and unique FAC system, and is not an extension of the region 1 system from other local times. The events are examined comprehensively by making use of a mulit-instrumental data set, which includes magnetic field, particle flux, electric field, auroral UV image data from the satellites, and the Sondrestrom convection data. The results are summarized as follows: (1) Region 2 currents flow mostly in the central plasma sheet (CPS) precipitation region, often overlapping with the boundary plasma sheet (BPD) at their poleward edge. (2) The region 1 system is located in the core part of the auroral oval and is confined in a relatively narrow range in latitude which includes the convection reversal. The low-latitude boundary layer, possibly including the outer part of the plasma sheet, and the external cusp are the major source regions of dayside region 1 currents. (2) Midday region O currents flow on open field lines and are collocated with the shear of antisunward convection flows with velocites decreasing poleward. On the basis of these results we support the view that both prenoon and postnoon current systems consist of the three-sheet structure when the disctortion ofthe convection pattern associated with interplanetary magnetic field (IMF) B(sub Y) is small and both morningside and eveningside convection cells are crescent-shaped. We also propose that the midday region O and a part of the region 1 systems are closely coupled to the same source.

Ohtani, S.↗

NASA NTRS2009

Turbulent Wing-Leading-Edge Correlation Assessment for the Shuttle Orbiter

This study was conducted in support of the Orbiter damage assessment activity that takes place for each Shuttle mission since STS-107 (STS - Space Transportation System). As part of the damage assessment activity, the state of boundary layer (laminar or turbulent) during reentry needs to be estimated in order to define the aerothermal environment on the Orbiter. Premature turbulence on the wing leading edge (WLE) is possible if a surface irregularity promotes early transition and the resulting turbulent wedge flow contaminates the WLE flow. The objective of this analysis is to develop a criterion to determine if and when the flow along the WLE experiences turbulent heating given an incoming turbulent boundary layer that contaminates the attachment line. The data to be analyzed were all obtained as part of the MH-13 Space Shuttle Orbiter Aerothermodynamic Test conducted on a 1.8%-scale Orbiter model at Calspan/University of Buffalo Research Center in the Large Energy National Shock Tunnels facility. A rational framework was used to develop a means to assess the state of the WLE flow on the Orbiter during reentry given a contaminated attachment-line flow. Evidence of turbulent flow on the WLE has been recently documented for a few STS missions during the Orbiter s flight history, albeit late in the reentry trajectory. The criterion developed herein will be compared to these flight results.

King, Rudolph A.↗

NASA NTRS1952

Experimental Investigation of Average Heat-Transfer and Friction Coefficients for Air Flowing in Circular Tubes Having Square-Thread-Type Roughness

An investigation of forced-convection heat transfer and associated pressure drops was conducted with air flowing through electrically heated Inconel tubes having various degrees of square-thread-type roughness, an inside diameter of 1/2 inch, and a length of 24 inches. were obtained for tubes having conventional roughness ratios (height of thread/radius of tube) of 0 (smooth tube), 0.016, 0.025, and 0.037 over ranges of bulk Reynolds numbers up to 350,000, average inside-tube-wall temperatures up to 1950deg R, and heat-flux densities up to 115,000 Btu per hour per square foot. Data The experimental data showed that both heat transfer and friction increased with increase in surface roughness, becoming more pronounced with increase in Reynolds number; for a given roughness, both heat transfer and friction were also influenced by the tube wall-to-bulk temperature ratio. Good correlation of the heat-transfer data for all the tubes investigated was obtained by use of a modification of the conventional Nusselt correlation parameters wherein the mass velocity in the Reynolds number was replaced by the product of air density evaluated at the average film temperature and the so-called friction velocity; in addition, the physical properties of air were evaluated at the average film temperature. The isothermal friction data for the rough tubes, when plotted in the conventional manner, resulted in curves similar to those obtained by other investigators; that is, the curve for a given roughness breaks away from the Blasius line (representing turbulent flow in smooth tubes) at some value of Reynolds number, which decreases with increase in surface roughness, and then becomes a horizontal line (friction coefficient independent of Reynolds number). A comparison of the friction data for the rough tubes used herein indicated that the conventional roughness ratio is not an adequate measure of relative roughness for tubes having a square-thread-type element. The present data, as well as those of other investigators, were used to isolate the influence of ratios of thread height to width, thread spacing to width, and the conventional roughness ratio on the friction coefficient. A fair correlation of the friction data was obtained for each tube with heat addition when the friction coefficient and Reynolds number were defined on the basis of film properties; however, the data for each tube retained the curve characteristic of that particular roughness. The friction data for all the rough tubes could be represented by a single line for the complete turbulence region by incorporating a roughness parameter in the film correlation. No correlation was obtained for the region of incomplete turbulence.

Sams, E. W.↗

NASA NTRS1986

Magnetic shear. III - Hale region 17255

Hale active region 17255, which in many respects was the most vigorous active region observed during the first operational period of SMM, appears to lie between two large areas of flow (observed in C IV) converging toward the major axis of the region. In the 6-day period from November 6-12, 1980, the major axis of the region rotates by about 25 deg. Several segments of the magnetic neutral line show C IV flow velocities of opposite sign on either side of the neutral line. Those segments whose orientation is favorable for measuring velocity components parallel to the neutral line show evidence that such flow is present, which is interpreted as evidence for magnetic shear. This, together with other evidence, suggests that magnetic shear is widespread in this region, as in the two previous regions studied. It is concluded that magnetic shear is often associated with flaring activity but is not a sufficient condition for flaring to occur.

Athay, R. G.↗

NASA NTRS1997

Analysis of Emission Spectra from Arc-jet Shock Layer Flows

This paper reports computational comparisons with experimental studies of a nonequilibrium blunt body shock layer in a high enthalpy arc-jet wind tunnel at NASA Ames Research Center. The primary objective of this work is to investigate the existence of a thermochemical equilibrium region in the shock layer. The existence of such an equilibrium region is of interest for following reasons: (1) to understand the equilibration process behind the shock in an arc-jet flow environment; (2) to interpret measured surface heat transfer data for purpose of determining surface catalytic efficiency, and (3) to determine the total enthalpy from the spectroscopic measurements. The paper will present an analysis of the experimental data obtained in the arc-jet wind tunnel. Experimental data includes measurements of emission spectra of radiation emanating from a shock layer formed in front of a 6-inch flat-faced cylinder. The measurements, obtained using a two dimensional CCD camera mounted on a spectrograph, provide spatially resolved spectra along the stagnation streamline of the model. Computational analysis includes simulation of nonequilibrium flow in the arc-jet facility (flow in the conical nozzle and shock layer in front of a flat-faced cylinder) using 2-D/axisymmetric Navier-Stokes codes and prediction of the radiation spectra from the axisymmetric flowfield using NEQAIR radiation code. Various line-of-sight averaged flow properties such as vibrational and rotational temperatures, species number densities within the shock layer are deduced from the experimental spectra. Comparison of the computed and experimental line-of-sight averaged flow properties provides assessment of thermochemical equilibration processes in an arc-jet shock layer.

Gokcen, T.↗

NASA NTRS1994

Raman-shifting an ArF excimer laser to generate new lines for obtaining optical diagnostic based information in flow fields

The application of tunable excimer lasers in combustion and flow diagnostics is almost routine nowadays. The properties of this laser system that enable density and temperature measurements in supersonic and hypersonic flow fields to be conducted are its high power, high repetition rate, and high spectral brightness. The limitation imposed by this system on these measurements is the paucity of lines in the wavelength region, the vacuum-ultraviolet, where species of interest, such as OH, N2, O2, H2, H2O, CO, NO, etc., are susceptible to electronic excitation to high-lying states. To circumvent this problem one normally resorts to nonlinear optical techniques such as frequency conversion via stimulated Raman scattering (SRS), more commonly known as Raman shifting or Raman mixing, to extend these nonintrusive and nonperturbing techniques to the shorter wavelengths in the VUV region and, for that matter, to longer wavelengths in the infrared region, if the need arises. The theoretical basis of SRS and its application are well documented in the literature. In essence, the Raman shift is a consequence of the inelastic scattering of the incident radiation by the sample. Most of the scattered radiation from the molecules of the sample is unchanged in frequency. However, a small fraction of the incident radiation is changed in frequency. This shift is a result of the fact that some of the incident photons on colliding with the molecules of the sample give up some of their energy and emerge with a lower energy resulting in the lower-frequency Stokes radiation. Other incident photons may increase their energy by colliding with the vibrationally excited molecules of the medium and emerge as higher-frequency antistokes radiation. The generation of the latter is the main objective of this project. The process, however, depends on several factors, including the beam quality of the pump laser, the cross-section of the gaseous medium, the gas pressure, and the ambient temperature of the gas near the focal region. Furthermore, since the Raman shifting process is polarization sensitive, it is necessary to have all of the laser energy in a single polarization. These factors were taken into consideration in the execution of the project. The implementation of the Raman shift was accomplished by focusing the 193 nm output of an ArF excimer laser (Lamda-Physik LPX 150) into a 1-meter long high pressure recirculating Raman cell filled with H2 gas. The laser system was modified in order to improve the mode quality of the pump beam to enhance the Raman shifting. To accomplish this feat, a prism beam expander and grating on the oscillator discharge provided wavelength tuning over the excimer gain profile. Furthermore, a triple-pass configuration, as opposed to unstable resonator optics, was employed in the operation of the amplifier cavity so that when the oscillator output radiation, focused by a 51-cm focal length fused silica lens through a 50 micron pinhole (serving as a spatial filter) and recollimated with a 25-cm focal length lens, was fed into the amplifier, it was injection locked, thereby providing tunable radiation with relatively low divergence. The forward scattered radiation emanating from the impingement of the modified pump beam on the Raman cell was detected using an energy meter after the latter had been separated from it using a dispersing prism.

Koker, Edmond B.↗

NASA NTRS1983

Flow improvements in the circuit of the Langley 4- by 7-meter tunnel

In order to identify the most promising means for improving the flow in the Langley 4- by 7-Meter Tunnel, detailed surveys of the mean velocity profiles were measured in both the horizontal and vertical planes of symmetry at specific locations throughout the tunnel circuit. These data were obtained at test-section dynamic pressures of 1.53, 2.78, and 4.79 kPa (3 2, 58, and 100 psf, respectively) for tunnel operation in both the closed and open test-section configurations. In the base-line tunnel-flow surveys, the flow patterns near the end of the test section indicate a uniform mean velocity distribution. Downstream of the test section, unsymmetrical flow patterns result in low velocities along the inner walls and in flow separation along the inner wall of the diffuser upstream of the drive fan and along the outer wall of the large diffuser downstream of the drive fan. In order to correct these unsymmetrical flow patterns, a set of trailing-edge flaps attached to the five flow-control vanes located just downstream of the first corner were installed. These flaps were very successful in making the tunnel flow more symmetrical and in eliminating the regions of separation in the diffusers upstream and downstream of the drive fan.

Zachary T Applin↗

NASA NTRS1991

Driven reconnection in the earth's magnetotail

In the standard reconnection model, a low flow speed leads to steady reconnection at a distant-tail x-line, but a high flow speed leads to the formation of a near-earth x-line and the onset of an auroral substorm. This paper discusses recent work which suggests that a pile-up of magnetic flux in the earth's magnetotail will occur whenever reconnection is strongly driven by the solar wind and that the near-earth x-line might result from a flux pile-up at the distant-tail x-line.

Forbes, T. G.↗

NASA NTRS2007

Eta Carinae: X-ray Line Variations during the 2003 X-ray Minimum, and the Orbit Orientation

The future evolution of Eta Carinae will be as a supernova (or hypernova) and black hole. The evolution is highly contingent on mass and angular momentum changes and instabilities. The presence of a companion can serve to trigger instabilities and provide pathways for mass and angular momentum exchange loss. X-rays can be used a a key diagnostic tool: x-ray temperatures trace pre-shock wind velocities, periodic x-ray variability traces the orbit, and x-ray line variations traces the flow and orientation of shocked gas. This brief presentation highlights x-ray line variations from the HETG and presents a model of the colliding wind flow.

Corcoran, M. F.↗

NASA NTRS1972

Computer program for calculating supersonic flow on the windward side conical delta wings by the method of lines

A user's manual is presented for a program that calculates the supersonic flow on the windward side of conical delta wings with shock attached at the sharp leading edge by the method of lines. The program also has a limited capability for computing the flow about circular and elliptic cones at incidence. It provides information including the shock shape, flow field, isentropic surface-flow properties, and force coefficients. A description of the program operation, a sample computation, and a FORTRAN 4 program listing are included.

Klunker, E. B.↗

NASA NTRS1993

Communications and control for electric power systems: Power flow classification for static security assessment

This report investigates the classification of power system states using an artificial neural network model, Kohonen's self-organizing feature map. The ultimate goal of this classification is to assess power system static security in real-time. Kohonen's self-organizing feature map is an unsupervised neural network which maps N-dimensional input vectors to an array of M neurons. After learning, the synaptic weight vectors exhibit a topological organization which represents the relationship between the vectors of the training set. This learning is unsupervised, which means that the number and size of the classes are not specified beforehand. In the application developed in this report, the input vectors used as the training set are generated by off-line load-flow simulations. The learning algorithm and the results of the organization are discussed.

Niebur, D.↗

DOE OSTI2016

DISCOVERY OF AN EXTREMELY WIDE-ANGLE BIPOLAR OUTFLOW IN AFGL 5142

Most bipolar outflows are associated with individual young stellar objects and have small opening angles. Here we report the discovery of an extremely wide-angle (∼180°) bipolar outflow (“EWBO”) in a cluster forming region AFGL 5142 from low-velocity emission of the HCN (3–2) and HCO{sup +} (3–2) lines. This bipolar outflow is along a north-west to south-east direction with a line of sight flow velocity of about 3 km s{sup −1} and is spatially connected to the high-velocity jet-like outflows. It seems to be a collection of low-velocity material entrained by the high-velocity outflows due to momentum feedback. The total ejected mass and mass loss rate due to both high-velocity jet-like outflows and the “EWBO” are ∼24.5 M {sub ⊙} and ∼1.7 × 10{sup −3} M {sub ⊙} yr{sup −1}, respectively. Global collapse of the clump is revealed by the “blue profile” in the HCO{sup +} (1–0) line. A hierarchical network of filaments was identified in NH{sub 3} (1, 1) emission. Clear velocity gradients of the order of 10 km s{sup −1} pc{sup −1} are found along filaments, indicating gas inflow along the filaments. The sum of the accretion rate along filaments and mass infall rate along the line of sight is ∼3.1 × 10{sup −3} M {sub ⊙} yr{sup −1}, which exceeds the total mass loss rate, indicating that the central cluster is probably still gaining mass. The central cluster is highly fragmented and 22 condensations are identified in 1.1 mm continuum emission. The fragmentation process seems to be determined by thermal pressure and turbulence. The magnetic field may not play an important role in fragmentation.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2022

Solar Flare Heating with Turbulent Suppression of Thermal Conduction

During solar flares plasma is typically heated to very high temperatures, and the resulting redistribution of energy via thermal conduction is a primary mechanism transporting energy throughout the flaring solar atmosphere. The thermal flux is usually modeled using Spitzer’s theory, which is based on local Coulomb collisions between the electrons carrying the thermal flux and those in the background. However, often during flares, temperature gradients become sufficiently steep that the collisional mean free path exceeds the temperature gradient scale size, so that thermal conduction becomes inherently non-local. Further, turbulent angular scattering, which is detectable in nonthermal widths of atomic emission lines, can also act to increase the collision frequency and so suppress the heat flux. Recent work by Emslie & Bian (2018) extended Spitzer’s theory of thermal conduction to account for both non-locality and turbulent suppression. We have implemented their theoretical expression for the heat flux (which is a convolution of the Spitzer flux with a kernel function) into the RADYN flare-modeling code and performed a parameter study to understand how the resulting changes in thermal conduction affect flare dynamics and hence the radiation produced. We find that models with reduced heat fluxes predict slower bulk flows, less intense line emission, and longer cooling times. By comparing features of atomic emission lines predicted by the models with Doppler velocities and nonthermal line widths deduced from a particular flare observation, we find that models with suppression factors between 0.3 to 0.5 relative to the Spitzer value best reproduce observed Doppmission lines forming over a wide range of temperatures. Interestingly, the model that best matches observed nonthermal line widths has a kappa-type velocity distribution function.

Joel C. Allred↗

NASA NTRS2022

Solar Flare Heating with Turbulent Suppression of Thermal Conduction

During solar flares plasma is typically heated to very high temperatures, and the resulting redistribution of energy via thermal conduction is a primary mechanism transporting energy throughout the flaring solar atmosphere. The thermal flux is usually modeled using Spitzer’s theory, which is based on local Coulomb collisions between the electrons carrying the thermal flux and those in the background. However, often during flares, temperature gradients become sufficiently steep that the collisional mean free path exceeds the temperature gradient scale size, so that thermal conduction becomes inherently non-local. Further, turbulent angular scattering, which is detectable in nonthermal widths of atomic emission lines, can also act to increase the collision frequency and so suppress the heat flux. Recent work by Emslie & Bian (2018) extended Spitzer’s theory of thermal conduction to account for both non-locality and turbulent suppression. We have implemented their theoretical expression for the heat flux (which is a convolution of the Spitzer flux with a kernel function) into the RADYN flare-modeling code and performed a parameter study to understand how the resulting changes in thermal conduction affect flare dynamics and hence the radiation produced. We find that models with reduced heat fluxes predict slower bulk flows, less intense line emission, and longer cooling times. By comparing features of atomic emission lines predicted by the models with Doppler velocities and nonthermal line widths deduced from a particular flare observation, we find that models with suppression factors between 0.3 to 0.5 relative to the Spitzer value best reproduce observed Doppler velocities across emission lines forming over a wide range of temperatures. Interestingly, the model that best matches observed nonthermal line widths has a kappa-type velocity distribution function

Solar flares↗

NASA NTRS1992

Effects of forebody strakes and Mach number on overall aerodynamic characteristics of configuration with 55 deg cropped delta wing

A wind tunnel data base was established for the effects of chine-like forebody strakes and Mach number on the longitudinal and lateral-directional characteristics of a generalized 55 degree cropped delta wing-fuselage-centerline vertical tail configuration. The testing was conducted in the 7- by 10-Foot Transonic Tunnel at the David Taylor Research Center at free-stream Mach numbers of 0.40 to 1.10 and Reynolds numbers based on the wing mean aerodynamic chord of 1.60 x 10(exp 6) to 2.59 x 10(exp 6). The best matrix included angles of attack from 0 degree to a maximum of 28 degree, angles of sidesip of 0, +5, and -5 degrees, and wing leading-edge flat deflection angles of 0 and 30 degrees. Key flow phenomena at subsonic and transonic conditions were identified by measuring off-body flow visualization with a laser screen technique. These phenomena included coexisting and interacting vortex flows and shock waves, vortex breakdown, vortex flow interactions with the vertical tail, and vortices induced by flow separation from the hinge line of the deflected wing flap. The flow mechanisms were correlated with the longitudinal and lateral-directional aerodynamic data trends.

Erickson, Gary E.↗