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Theory and design of a pneumatic temperature probe and experimental results obtained in a high-temperature gas stream

Description: Report presenting a discussion of the basic theory of pneumatic temperature probes and deviations from the basic theory in practical applications. Design requirements and operating conditions are discussed. Results regarding calibration tests and high-temperature tests and results are provided.
Date: January 1957
Creator: Simmons, Frederick S. & Glawe, George E.
Partner: UNT Libraries Government Documents Department

Radiation and recovery corrections and time constants of several chromel-alumel thermocouple probes in high-temperature, high-velocity gas streams

Description: Report presenting an experimental determination of radiation and recovery corrections and time constraints for several designs of shielded and unshielded thermocouple probes using chromel-alumel wire. Radiation and time constant data were obtained for Mach numbers from 0.3 to 0.9 and a range of static pressures and temperatures. Tables and graphs are presented which show the correction factors of the various designs to aid in selecting a probe for a particular application.
Date: October 1956
Creator: Glawe, George E.; Simmons, Frederick S. & Stickney, Truman M.
Partner: UNT Libraries Government Documents Department

Several Combination Probes for Surveying Static and Total Pressure and Flow Direction

Description: Report presenting an investigation to provide a basis for the design of combination probes intended to survey the static and total pressure and direction of flow with special reference to subsonic turbo-machine testing. Static-pressure probes, yaw-element probes, claw-type yaw probes, and combination probes were tested in an 8-inch-diameter calibration tunnel. The factors that determine the sensitivity of claw-type yaw probes were determined from this test.
Date: November 1952
Creator: Schulze, Wallace M.; Ashby, George C., Jr. & Erwin, John R.
Partner: UNT Libraries Government Documents Department

Averaging of Periodic Pressure Pulsations by a Total-Pressure Probe

Description: Note presenting information on the average pressure indicated by a total-pressure probe subjected to a stagnation pressure that alternates periodically between two constant values. Calculated and experimental data are in good agreement and errors are reduced when the probe design is such as to ensure laminar-flow pulsations in the probe at all times.
Date: October 1955
Creator: Johnson, R. C.
Partner: UNT Libraries Government Documents Department

Design and calibration of a total-temperature probe for use at supersonic speeds

Description: Report presenting a study of the factors involved in the design of total-temperature probes for use at supersonic speeds as applied to the design of an instrument to be used in wind-tunnel calibrations. Tests of the probe showed that the calibration factor required in the conversion of the measured temperature to the true total temperature was 0.992 for a range of Mach numbers.
Date: May 1949
Creator: Goldstein, David L. & Scherrer, Richard
Partner: UNT Libraries Government Documents Department

Vacuum Probe, Standard Leaks, and Needle Valve for Use with the Helium Leak Detector

Description: The following report is split into four parts describing the usage of a vacuum probe for leak hunting with the Helium Leak Detector, the two types of Standard Leaks that were designed to measure the sensitivity of the detector, the development of a needle valve adjusted for controlling the flow of a standard mixture of helium and air into the leak detector for a sensitivity check by the single leak method, and a worm and gear adjustment developed to facilitate throttling of the Helium Leak Detector on a vacuum header equipped with the 3/8" Kerotect angle valve.
Date: August 1945
Creator: Samuel, A. J.
Partner: UNT Libraries Government Documents Department

Steady-state and Dynamic Probe Characteristics in a Low-density Plasma

Description: The problem with which this investigation is concerned is that of determining the steady-state and dynamic characteristics of the admittance of a metallic probe immersed in a laboratory plasma which has the low electron densities and low electron temperatures characteristic of the ionospheric plasma. The problem is separated into three related topics: the design and production of the laboratory plasma, the measurement of the steady-state properties of dc and very low frequency probe admittance, and the study of transient ion sheath effects on radio frequency probe admittance.
Date: December 1970
Creator: Bunting, William David
Partner: UNT Libraries

Compact Probe for Power Detection from the Narrow Side of the Waveguide

Description: Phased array antennas with high directivity have a variety of applications. One of their applications is in RF heating for magnetically confined plasma fusion research. Among these RF heating schemes, waveguide arrays with careful phase control on each waveguide can act as a phased array antenna to deliver megawatts of power for heating fusion plasmas in the lower-hybrid range of frequencies (1 GHz-10 GHz). In order to achieve compactness, it is common to stack reduced height waveguide together to form the waveguide array. As long as the delivered power does not cause arcing in the waveguide, the waveguide height can be quite small. Due to this confined space in a stack of reduced height waveguides, power detection of the incident and reflected wave in the reduced height waveguide is extremely difficult. A new compact probe, which employs current loops, to monitor the incident and reflected wave from the narrow side of the reduced height waveguide has been developed. Its theory and performance will be reported in this paper.
Date: May 2004
Creator: Kung, C. C.; Bernabei, S.; Gumbas, J.; Greenough, N.; Fredd, E.; Wilson, J. R. et al.
Partner: UNT Libraries Government Documents Department

Technical assessment of BY-1 12 liquid observation well (LOW) anomalous readings

Description: This document contains a technical assessment of the cause and disposition of Interstitial Liquid Level(ILL) readings taken in February 1997 on Hanford waste tank 241-BY-112 that were below specified limits. Some readings were determined to be spurious while other readings were below the limit because of normal data scatter. The data assessment did discover that a new ILL had formed below the currently established baseline because of the normal drainage of the interstitial liquid over time. A new baseline and limit will be established. Because the new ILL appears to be stable and consistent with post saltwell pumping behavior, and because there is no other evidence to the contrary, the tank is judged not to be leaking.
Date: March 11, 1997
Creator: Barnes, D. A. & Reed, R. W.
Partner: UNT Libraries Government Documents Department

Recovery and time-response characteristics of six thermocouple probes in subsonic and supersonic flow

Description: Experimental data obtained from three shielded and three unshielded thermocouple probes are presented. Data taken in air at room temperature over the ranges 0.2 to 2.2 Mach number and 0.2 to 2.2 atmospheres total pressure show reproducible systematic variations of recovery with Mach number, ambient pressure, flow angle, and probe design. Time-constant data determined at Mach 0.2 and room temperature and pressure indicate that unshielded probes are several times faster in response to temperature changes than shielded probes.
Date: July 1955
Creator: Stickney, Truman M.
Partner: UNT Libraries Government Documents Department

Viscosity Corrections to Cone Probes on Rarefied Supersonic Flow at a Nominal Mach Number of 4

Description: Note presenting data obtained for the viscosity corrections to cone probes in supersonic rarefied air flow at a nominal Mach number of 4. The test models consisted of a set of seven geometrically similar 5 degree semivertex-angle cones. Results regarding cone surface pressure distributions, calibration data for geometrically similar cones, orifices size effect, and tests at other Mach numbers are provided.
Date: November 1954
Creator: Talbot, L.
Partner: UNT Libraries Government Documents Department

Universality of Unintegrated Gluon Distributions at small x

Description: We systematically study dijet production in various processes in the small-x limit and establish an effective kt-factorization for hard processes in a system with dilute probes scattering on a dense target. In the large-Nc limit, the unintegrated gluon distributions involved in different processes are shown to be related to two widely proposed ones: the Weizsacker-Williams gluon distribution and the dipole gluon distribution.
Date: January 4, 2011
Creator: Dominguez, Fabio; Marquet, Cyrille; Xiao, Bowen & Yuan, Feng
Partner: UNT Libraries Government Documents Department

Negative differential mobility of weakly driven particles in models of glass formers

Description: We study the response of probe particles to weak constant driving in kinetically constrained models of glassy systems, and show that the probe's response can be non-monotonic and give rise to negative differential mobility: increasing the applied force can reduce the probe's drift velocity in the force direction. Other significant non-linear effects are also demonstrated, such as the enhancement with increasing force of the probe's fluctuations away from the average path, a phenomenon known in other contexts as giant diffusivity. We show that these results can be explained analytically by a continuous-time random walk approximation where there is decoupling between persistence and exchange times for local displacements of the probe. This decoupling is due to dynamic heterogeneity in the glassy system, which also leads to bimodal distributions of probe particle displacements. We discuss the relevance of our results to experiments.
Date: April 1, 2008
Creator: Jack, Robert L.; Kelsey, David; Garrahan, Juan P. & Chandler, David
Partner: UNT Libraries Government Documents Department

Measurement of the Behavior of a Plasma in a Magnetic Field by Means of Probes

Description: Abstract: "Probes were used to measure certain properties of the cloud of positive ions and electrons ejected from a pulsed ion source having two hydrogen-loaded electrodes. Time-of-flight measurements show: the presence of H+ ions with 50 ev directed energy; an increase of this energy with increasing pulse current in the source; a higher peak yield of ions with higher peak currents in the source; and higher yields and higher ion energies up to 110 ev have been recorded with the use of a pulsed magnetic field impressed upon the source. The neutral positive ion-electron beam from the source has been projected against an increasing magnetic field and the reflected and transmitted signals have been recorded and compared as a function of the magnetic field. Probe signals from the plasma as it encounters the magnetic field are oscillatory, suggesting that magnetohydrodynamic phenomena are presented."
Date: December 1, 1954
Creator: Bostick, W. H.; Zizzo, S. G. & Cook, Buford
Partner: UNT Libraries Government Documents Department

High-resolution magnetic imaging and investigations of thin-film magnetism with spin-polarized electron, ion and atom probes. Progress report, November 1, 1994--October 31, 1995

Description: This is a progress report for the period 1 November, 1994 to 31 October, 1995. Research during this grant year includes: (1) Completion of the Spin-Polarized Electron Energy Loss Spectroscopy (SPEELS) research program. (2) Design of an improved and much more intense metastable atom source that can also be converted to a Rydberg atom beam, for continuing studies utilizing Spin-Polarized Metastable (Atom) Deexcitation Spectroscopy (SPMDS), and to initiate new investigations of interactions of Rydberg atoms with surfaces. (3) Development of a spin-polarized He{sup +} ion source for studies of ion-surface interaction dynamics and epitaxially grown magnetic films utilizing Spin-Polarized Ion Neutralization Spectroscopy (SPINS).
Date: April 1, 1995
Creator: Walters, G.K. & Dunning, F.B.
Partner: UNT Libraries Government Documents Department

Diagnostic Setup for Characterization of Near-Anode Processes in Hall Thrusters

Description: A diagnostic setup for characterization of near-anode processes in Hall-current plasma thrusters consisting of biased and emissive electrostatic probes, high-precision positioning system and low-noise electronic circuitry was developed and tested. Experimental results show that radial probe insertion does not cause perturbations to the discharge and therefore can be used for accurate near-anode measurements.
Date: September 8, 2003
Creator: Dorf, L.; Raitses, Y. & Fisch, N.J.
Partner: UNT Libraries Government Documents Department

New Methodology For Use in Rotating Field Nuclear MagneticResonance

Description: High-resolution NMR spectra of samples with anisotropicbroadening are simplified to their isotropic spectra by fast rotation ofthe sample at the magic angle 54.7 circ. This dissertation concerns thedevelopment of novel Nuclear Magnetic Resonance (NMR) methodologies basedwhich would rotate the magnetic field instead of the sample, rotatingfield NMR. It provides an over of the NMR concepts, procedures, andexperiments needed to understand the methodologies that will be used forrotating field NMR. A simple two-dimensional shimming method based onharmonic corrector rings which can provide arbitrary multiple ordershimming corrections were developed for rotating field systems, but couldbe used in shimming other systems as well. Those results demonstrate, forexample, that quadrupolar order shimming improves the linewidth by up toan order of magnitude. An additional order of magnitude reduction is inprinciple achievable by utilizing this shimming method for z-gradientcorrection and higher order xy gradients. A specialized pulse sequencefor the rotating field NMR experiment is under development. The pulsesequence allows for spinning away from the magic angle and spinningslower than the anisotropic broadening. This pulse sequence is acombination of the projected magic angle spinning (p-MAS) and magic angleturning (MAT) pulse sequences. This will be useful to rotating field NMRbecause there are limits on how fast a field can be spun and spin at themagic angle is difficult. One of the goals of this project is forrotating field NMR to be used on biological systems. The p-MAS pulsesequence was successfully tested on bovine tissue samples which suggeststhat it will be a viable methodology to use in a rotating field set up. Aside experiment on steering magnetic particle by MRI gradients was alsocarried out. Some movement was seen in these experiment, but for totalcontrol over steering further experiments would need to bedone.
Date: May 18, 2007
Creator: Jachmann, Rebecca C.
Partner: UNT Libraries Government Documents Department

Dependence of secondary electron image contrast of periodic objects upon probe diameter

Description: The effect of probe diameter upon secondary electron image contrast of periodic objects has been studied systematically. Interest in the topic arose following the observation of out-of-focus SEM images of conventional mesh support grids, where the basic periodicity was visible even with probe diameters many times the periodic spacing. The instrument used was a JEM-120CX/ASID operated in the SEM mode at low magnification with the objective lens off and other lenses in the free-control mode. The probe diameter at the specimen position was controlled by the continuously variable second condenser lens current. The first intermediate lens was focussed at the specimen position, thus allowing a determination of the probe diameter from the magnified shadow image, which could be photographed using the conventional TEM camera. The specimen used was a copper bar grid with spacings approx. = 125 ..mu..m.
Date: January 1, 1979
Creator: Bentley, J & Carpenter, R W
Partner: UNT Libraries Government Documents Department

Investigations of Probe Induced Perturbations in a Hall Thruster

Description: An electrostatic probe used to measure spatial plasma parameters in a Hall thruster generates perturbations of the plasma. These perturbations are examined by varying the probe material, penetration distance, residence time, and the nominal thruster conditions. The study leads us to recommendations for probe design and thruster operating conditions to reduce discharge perturbations, including metal shielding of the probe insulator and operation of the thruster at lower densities.
Date: August 12, 2002
Creator: Staack, D.; Raitses, Y. & Fisch, N.J.
Partner: UNT Libraries Government Documents Department

Physical Limitations on the Measurement of Transient Fields in Air and in Dissipative Media Using Electric and Magnetic Probes

Description: The properties of electric and magnetic probes for the measurement of transient electromagnetic fields in air and in dissipative media are discussed briefly, It is shown that the effective height of an electrically small loop is independent of the ambient medium. This is also virtually true for a thin electrically short dipole (or monopole). If the open-circuit voltage of a magnetic probe can be measured accurately, it is possible (in principle) to reconstruct the time history of the incident magnetic field, even if the loop is immersed in dissipative media of unknown characteristics. The time function of the open-circuit voltage of an electric probe is essentially a replica of the time history of the incident electric field. In some schemes, the probes are lumped impedance loaded, and the voltage drop across the load impedances is measured. The source impedances of the probes are then involved in the equivalent circuits of the receiving antennas, and the leading terms in the expressions for these impedances depend on the properties of the environment. If an electrically short monopole is base-loaded by a capacitor divider, the voltage wave appearing across any capacitor is a faithful reproduction of the time sequence of the incident electric field provided the measurement is made in air or other dielectric. (auth)
Date: November 1, 1963
Creator: Harrison, C. W., Jr.
Partner: UNT Libraries Government Documents Department

TiO2 Nanoparticles as a Soft X-ray Molecular Probe

Description: With the emergence of soft x-ray techniques for imaging cells, there is a pressing need to develop protein localization probes that can be unambiguously identified within the region of x-ray spectrum used for imaging. TiO2 nanocrystal colloids, which have a strong absorption cross-section within the "water-window" region of x-rays, areideally suited as soft x-ray microscopy probes. To demonstrate their efficacy, TiO2-streptavidin nanoconjugates were prepared and subsequently labeled microtubules polymerized from biotinylated tubulin. The microtubules were imaged using scanning transmission x-ray microscopy (STXM), and the TiO2 nanoparticle tags were specifically identified using x-ray absorption near edge spectroscopy (XANES). These experiments demonstrate that TiO2 nanoparticles are potential probes for protein localization analyses using soft x-ray microscopy.
Date: June 30, 2007
Creator: Larabell, Carolyn; Ashcroft, Jared M.; Gu, Weiwei; Zhang, Tierui; Hughes, Steven M.; Hartman, Keith B. et al.
Partner: UNT Libraries Government Documents Department

Development of Neutron Probes for Characterization of Hazardous Materials in the Sub-surface Medium

Description: Neutron probes are being developed at the Idaho National Engineering and Environmental Laboratory (INEEL) for the detection, identification and quantification of hazardous materials in the ground. Such materials include plutonium, uranium, americium, chlorine and fluorine. Both a Neutron Gamma (NG) probe and a Prompt Fission Neutron (PFN) probe are being developed. The NG probe is used primarily for nuclide identification and quantification measurements. The PFN is used mostly for the detection and measurement of fissile material, but also for the determination of thermal neutron macroscopic absorption cross sections of the various elements comprising the ground matrix. Calibration of these probes will be carried out at the INEEL using an indoor facility that has been designed for this activity.
Date: May 15, 2002
Creator: Keegan, R.P.; McGrath, C.A. & Lopez, J.C.
Partner: UNT Libraries Government Documents Department