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Sample records for hot wire anemometers

  1. Method for making a hot wire anemometer and product thereof

    NASA Technical Reports Server (NTRS)

    Milkulla, V. (Inventor)

    1977-01-01

    A hot wire anemometer probe is described that includes a ceramic body supporting two conductive rods parallel to each other. The body has a narrow edge surface from which the rods protrude. A probe wire is welded to the rods and extends along the edge surface. A ceramic adhesive is used to secure the probe wire to the surface so that the probe wire is rigid. A method for fabricating the probe is also described in which the body is molded and precisely shaped by machining techniques before the probe wires are installed.

  2. Metallic hot wire anemometer. [for high speed wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Lemos, F. R. (Inventor)

    1977-01-01

    A hot wire anemometer is described which has a body formed of heat resistant metal such as an alloy high in nickel content which supports a probe wire disposed in a V groove in the body. The V groove contains a high temperature ceramic adhesive that partially encompasses the downstream side of the probe wire. Mechanical and electrical connection to the probe wire is achieved through conductive support rods that are constructed of the same high temperature metal, insulation between the body and the conductor rods being provided by a coating of an oxide of the same material which coating is formed in situ. The oxide coating insulates the conductor rods from the body, mechanically fixes the conductors within the body, and maintains its integrity at elevated temperatures.

  3. A high-performance constant-temperature hot-wire anemometer

    NASA Technical Reports Server (NTRS)

    Watmuff, Jonathan H.

    1994-01-01

    A high-performance constant-temperature hot-wire anemometer has been designed based on a system theory analysis that can be extended to arbitrary order. A motivating factor behind the design was to achieve the highest possible frequency response while ensuring overall system stability. Based on these considerations, the design of the circuit and the selection of components is discussed in depth. Basic operating instructions are included in an operator's guide. The analysis is used to identify operating modes, observed in all anemometers, that are misleading in the sense that the operator can be deceived by interpreting an erroneous frequency response. Unlike other anemometers, this instrument provides front panel access to all the circuit parameters which affect system stability and frequency response. Instructions are given on how to identify and avoid these rather subtle and undesirable operating modes by appropriate adjustment of the controls. Details, such as fabrication drawings and a parts list, are provided to enable others to construct the instrument.

  4. The Measurement of Fluctuations of Air Speed by the Hot-Wire Anemometer

    NASA Technical Reports Server (NTRS)

    Dryden, H L; Kuethe, A M

    1930-01-01

    The hot-wire anemometer suggests itself as a promising method for measuring the fluctuating air velocities found in turbulent flow. The only obstacle is the presence of a lag due to the limited energy input which makes even a fairly small wire incapable of following rapid fluctuations with accuracy. This paper gives the theory of the lag and describes an experimental arrangement for compensating for the lag for frequencies up to 100 or more per second when the amplitude of the fluctuation is not too great. An experimental test of the accuracy of compensation and some results obtained with the apparatus in a wind-tunnel air stream are described. While the apparatus is very bulky in its present form, it is believed possible to develop a more portable arrangement. (author)

  5. Hot wire anemometer measurements in the unheated air flow tests of the SRB nozzle-to-case joint

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.

    1988-01-01

    Hot-Wire Anemometer measurements made in the Solid Rocket Booster (SRB) nozzle-to-case joint are discussed. The study was undertaken to glean additional information on the circumferential flow induced in the SRB nozzle joint and the effect of this flow on the insulation bonding flaws. The tests were conducted on a full-scale, 2-D representation of a 65-in long segment of the SRB nozzle joint, with unheated air as the working fluid. Both the flight Mach number and Reynolds number were matched simultaneously and different pressure gradients imposed along the joint face were investigated. Hot-wire anemometers were used to obtain velocity data for different joint gaps and debond configurations. The procedure adopted for hot-wire calibration and use is outlined and the results from the tests summarized.

  6. Software corrected hot wire thermal lag for the constant voltage anemometer featuring a constant bandwidth at the selected compensation setting

    NASA Astrophysics Data System (ADS)

    Sarma, Garimella R.; Comte-Bellot, Genevieve; Faure, Thierry M.

    1998-09-01

    Software compensation correction for thermal lag of a hot wire in the application of a constant voltage anemometer (CVA) for turbulence measurements in the boundary layer of a supersonic wind tunnel has been demonstrated. The CVA was used with a fixed compensation setting while measuring the in situ thermal lag (time constant) of the hot wire. Using the measured time constant, corrections are applied to the fixed compensation output of the CVA in postprocessing of the data. To demonstrate the flexibility of the approach it was used for two compensation settings at a test point to obtain the same results from both settings. A unique advantage of this approach is shown to be that for a given compensation setting in the CVA the bandwidth of the measurements for the test remains constant for all of the different test conditions and yields higher productivity. The results of the turbulence levels measured with this method agree with earlier research using other anemometers. Spectral plots of the mass flux and temperature and the measured in situ time constant responses under different conditions of the hot wire have been presented.

  7. Aircraft-based in-situ calibration of a hot-wire anemometer in a compressible flow

    NASA Astrophysics Data System (ADS)

    Hugo, Ronald J.; Nowlin, Scott R.; Hahn, Ila L.; Bishop, Kenneth P.; McCrae, Kimberley A.

    1999-08-01

    High-bandwidth measurements of atmospheric velocity and temperature fluctuations in the high troposphere/low stratosphere using aircraft-based hot-wire anemometers requires calibration. An in-situ calibration characterizing wire sensitivity at high subsonic Mach numbers and relatively low temperatures and pressures was performed. Custom designed constant-temperature and constant-current anemometer equipment has been used for these atmospheric measurements. Two sets of calibration experiments are described, one in a controlled laboratory environment where the Mach number and temperature were varied and the other on board a C-135E aircraft. The aircraft test were conducted by varying the flight Mach number at different pressure altitudes while flying into an upper-level low pressure area, achieving variability in velocity, temperature, and pressure. Results obtained indicate increased sensitivity to velocity while operating the wire at a low overheat ratio. The calibration data was fit to a form of King's law which was found to work well for in-situ calibrations.

  8. High Reynolds Number Effects on Multi-Hole Probes and Hot Wire Anemometers

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Smith, A.; Gerry, G.; Kauffman, W.

    1995-01-01

    The paper reports on the results from an experimental investigation of the response of multi-hole and hot wire probes at high flow Reynolds numbers (Re approx. 10(exp 6)). The limited results available in literature for 5-hole probes are restricted to Re approx. 10(exp 4). The experiment aims to investigate the probe response (in terms of dimensionless pressure ratios, characterizing pitch, and yaw angles and the total and static pressures) at high Re values and to gauge their effect on the calculated velocity vector. Hot wire calibrations were also undertaken with a parametric variation of the flow pressure, velocity and temperature. Different correction and calibration schemes are sought to be tested against the acquired data set. The data is in the analysis stage at the present time. The test provided good benchmark quality data that can be used to test future calibration and testing methods.

  9. A calibration technique for a hot-wire-probe vector anemometer

    NASA Technical Reports Server (NTRS)

    Scheiman, J.; Marple, C.; Vann, D. S.

    1982-01-01

    Calibration tests using hot wires were conducted using a newly developed test rig that greatly reduced the data acquisition time. A comparison of measured and computed velocity vector magnitude and direction indicates the necessity of complete probe calibration to determine flow interference and/or operating limitation regions. Calibration results indicate that flow rates with 3 percent accuracy and flow angles with 5 deg accuracy are attainable.

  10. Note: Improving long-term stability of hot-wire anemometer sensors by means of annealing

    SciTech Connect

    Lundström, H.

    2015-08-15

    Annealing procedures for hot-wire sensors of platinum and platinum-plated tungsten have been investigated experimentally. It was discovered that the two investigated sensor metals behave quite differently during the annealing process, but for both types annealing may improve long-term stability considerably. Measured drift of sensors both without and with prior annealing is presented. Suggestions for suitable annealing temperatures and times are given.

  11. Note: Improving long-term stability of hot-wire anemometer sensors by means of annealing.

    PubMed

    Lundström, H

    2015-08-01

    Annealing procedures for hot-wire sensors of platinum and platinum-plated tungsten have been investigated experimentally. It was discovered that the two investigated sensor metals behave quite differently during the annealing process, but for both types annealing may improve long-term stability considerably. Measured drift of sensors both without and with prior annealing is presented. Suggestions for suitable annealing temperatures and times are given.

  12. A micro-scale hot wire anemometer based on low stress (Ni/W) multi-layers deposited on nano-crystalline diamond for air flow sensing

    NASA Astrophysics Data System (ADS)

    Talbi, A.; Gimeno, L.; Gerbedoen, J.-C.; Viard, R.; Soltani, A.; Mortet, V.; Preobrazhensky, V.; Merlen, A.; Pernod, P.

    2015-12-01

    A linear array of microscale thermal anemometers has been designed, fabricated and characterized. The sensitive element consists of a self-compensated-stress multilayer (Ni/W) patterned to form a wire with length, width, and thickness close to 200 μm, 5 μm and 2 μm respectively. The wire is deposited and supported by prongs made of nano-crystalline diamond (NCD) of about 2 μm in thickness. Due to its high Young’s modulus, NCD allows a very high mechanical toughness without the need for thicker support for the hot wire. Also, depending on grain size, the NCD is able to present thermal conductivity smaller than 10 W mK-1, providing good thermal insulation from the substrate and less conductive end losses to the prongs. The sensor was characterized experimentally. Its electrical and thermal properties were obtained first in the absence of fluid flow. The results confirm the effectiveness of thermal insulation and the mechanical robustness of the structure. The fluidic characterizations were performed and analysed in the case of an airflow with velocities of up to 30 m s-1.

  13. The Design and Use of a Temperature-Compensated Hot-Film Anemometer System for Boundary-Layer Flow Transition Detection on Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Chiles, Harry R.

    1988-01-01

    An airborne temperature-compensated hot-film anemometer system has been designed, fabricated, and used to obtain in-flight airfoil boundary-layer flow transition data by the NASA Ames-Dryden Flight Research Facility. Salient features of the anemometer include near constant sensitivity over the full flight envelope, installation without coaxial wiring, low-noise outputs, and self-contained signal conditioning with dynamic and steady-state outputs. The small size, low-power dissipation, and modular design make the anemometer suitable for use in modern high-performance research aircraft. Design of the temperature-compensated hot-film anemometer and its use for flow transition detection on a laminar flow flight research project are described. Also presented are data gathered in flight which is representative of the temperature-compensated hot-film anemometer operation at subsonic, transonic, and supersonic flight conditions.

  14. Hot wire in low Reynolds number flow

    NASA Technical Reports Server (NTRS)

    Kolb, M. A.; Covert, E. E.

    1984-01-01

    Progress reports were issued on the following experiments: (1) low Reynolds number flow phenomenon of periodic vortex shedding in the wake behind a cylinder as studied by applying the hot wire anemometer technique of flow measurement. The downstream diffusion of these shed vortices was of prime concern. An evaluation of the performance of the hot wire at low Reynolds number is also considered. (2) A brief examination of the back sections of the Wright Brothers wind tunnel circuits were conducted to establish whether or not gross flow deviations were present at corners, or turning vane regions. A calibration of the test sections was done. (3) The attractiveness of using rembedded grids for airfoil calculations modeled by the Euler equations was explored. These calculations were extended to C-type grids and then to Navier-Stokes calculations,

  15. A Hot-wire Circuit with Very Small Time Lag

    NASA Technical Reports Server (NTRS)

    Weske, John R

    1943-01-01

    A circuit for a hot-wire anemometer for the measurement of fluctuating flow is presented in the present report. The principal elements of the circuit are a Wheatstone bridge, one branch of which is the hot wire; and an electronic amplifier and a current regulator for the brief current which in combination maintain the bridge balance constant. Hence the hot wire is kept at practically constant resistance and temperature, and the time lag caused by thermal inertia of the wire is thereby reduced. Through the addition of a nonlinear amplifying stage the reading of the instrument has been rendered proportional to the velocity. A discussion of certain characteristics of the circuit and the results of related calibrating tests are given.

  16. Hot-Film and Hot-Wire Anemometry for a Boundary Layer Active Flow Control Test

    NASA Technical Reports Server (NTRS)

    Lenahan, Keven C.; Schatzman, David M.; Wilson, Jacob Samuel

    2013-01-01

    Unsteady active flow control (AFC) has been used experimentally for many years to minimize bluff-body drag. This technology could significantly improve performance of rotorcraft by cleaning up flow separation. It is important, then, that new actuator technologies be studied for application to future vehicles. A boundary layer wind tunnel was constructed with a 1ft-x-3ft test section and unsteady measurement instrumentation to study how AFC manipulates the boundary layer to overcome adverse pressure gradients and flow separation. This unsteady flow control research requires unsteady measurement methods. In order to measure the boundary layer characteristics, both hot-wire and hot-film Constant Temperature Anemometry is used. A hot-wire probe is mounted in the flow to measure velocity while a hot-film array lays on the test surface to measure skin friction. Hot-film sensors are connected to an anemometer, a Wheatstone bridge circuit with an output that corresponds to the dynamic flow response. From this output, the time varying flow field, turbulence, and flow reversal can be characterized. Tuning the anemometers requires a fan test on the hot-film sensors to adjust each output. This is a delicate process as several variables drastically affect the data, including control resistance, signal input, trim, and gain settings.

  17. Hot-wire calibration in subsonic/transonic flow regimes

    NASA Technical Reports Server (NTRS)

    Nagabushana, K. A.; Ash, Robert L.

    1995-01-01

    A different approach for calibrating hot-wires, which simplifies the calibration procedure and reduces the tunnel run-time by an order of magnitude was sought. In general, it is accepted that the directly measurable quantities in any flow are velocity, density, and total temperature. Very few facilities have the capability of varying the total temperature over an adequate range. However, if the overheat temperature parameter, a(sub w), is used to calibrate the hot-wire then the directly measurable quantity, voltage, will be a function of the flow variables and the overheat parameter i.e., E = f(u,p,a(sub w), T(sub w)) where a(sub w) will contain the needed total temperature information. In this report, various methods of evaluating sensitivities with different dependent and independent variables to calibrate a 3-Wire hot-wire probe using a constant temperature anemometer (CTA) in subsonic/transonic flow regimes is presented. The advantage of using a(sub w) as the independent variable instead of total temperature, t(sub o), or overheat temperature parameter, tau, is that while running a calibration test it is not necessary to know the recovery factor, the coefficients in a wire resistance to temperature relationship for a given probe. It was deduced that the method employing the relationship E = f (u,p,a(sub w)) should result in the most accurate calibration of hot wire probes. Any other method would require additional measurements. Also this method will allow calibration and determination of accurate temperature fluctuation information even in atmospheric wind tunnels where there is no ability to obtain any temperature sensitivity information at present. This technique greatly simplifies the calibration process for hot-wires, provides the required calibration information needed in obtaining temperature fluctuations, and reduces both the tunnel run-time and the test matrix required to calibrate hotwires. Some of the results using the above techniques are presented

  18. Design, Validation, and Testing of a Hot-Film Anemometer for Hypersonic Flow

    NASA Astrophysics Data System (ADS)

    Sheplak, Mark

    The application of constant-temperature hot-film anemometry to hypersonic flow has been reviewed and extended in this thesis. The objective of this investigation was to develop a measurement tool capable of yielding continuous, high-bandwidth, quantitative, normal mass-flux and total -temperature measurements in moderate-enthalpy environments. This research has produced a probe design that represents a significant advancement over existing designs, offering the following improvements: (1) a five-fold increase in bandwidth; (2) true stagnation-line sensor placement; (3) a two order-of-magnitude decrease in sensor volume; and (4) over a 70% increase in maximum film temperature. These improvements were achieved through substrate design, sensor placement, the use of high-temperature materials, and state -of-the-art microphotolithographic fabrication techniques. The experimental study to characterize the probe was performed in four different hypersonic wind tunnels at NASA-Langley Research Center. The initial test consisted of traversing the hot film through a Mach 6, flat-plate, turbulent boundary layer in air. The detailed static-calibration measurements that followed were performed in two different hypersonic flows: a Mach 11 helium flow and Mach 6 air flow. The final test of this thesis consisted of traversing the probe through the Mach 6 wake of a 70^ circ blunt body. The goal of this test was to determine the state (i.e., laminar or turbulent) of the wake. These studies indicate that substrate conduction effects result in instrumentation characteristics that prevent the hot-film anemometer from being used as a quantitative tool. The extension of this technique to providing quantitative information is dependent upon the development of lower thermal-conductivity substrate materials. However, the probe durability, absence of strain gauging, and high bandwidth represent significant improvements over the hot-wire technique for making qualitative measurements. Potential

  19. Plasma Anemometer Measurements and Optimization

    NASA Astrophysics Data System (ADS)

    Marshall, Curtis; Matlis, Eric; Corke, Thomas; Gogineni, Sivaram

    2013-11-01

    Velocity measurements using a constant-current plasma anemometer were performed in a Mach 0.4 jet in order to further optimize the anemometer design. The plasma anemometer uses an AC glow discharge (plasma) formed in the air gap between two protruding low profile electrodes as the flow sensing element. The output from the anemometer is an amplitude modulated version of the AC voltage input that contains information about the mean fluctuating velocity components. Experiments were performed to investigate the effect of the electrode gap, AC current, and AC frequency on the mean and fluctuating velocity sensitivity and repeatability of the sensor. This involved mean velocity calibrations from 0 to 140 m/s and mean and fluctuating velocity profiles through the shear layer of the jet. Measurements with a constant temperature hot-wire anemometer were used for reference. The results showed an improvement in performance with increasing AC frequency that was attributed a more stable glow discharge. The agreement with the hot-wire were good, with the advantage of the plasma anemometer being its 100-times higher frequency response. Supported by Air Force SBIR Phase II FA8650-11-C-2199.

  20. The wedge hot-film anemometer in supersonic flow

    NASA Technical Reports Server (NTRS)

    Seiner, J. M.

    1983-01-01

    A commercial wedge hot-film probe is studied to determine its heat transfer response in transonic to low supersonic flows of high unit Reynolds number. The results of this study show that its response in this flow regime differs from the response of cylindrical type sensors. Whereas the cylindrical sensor has the same sensitivity to velocity as to density for free-stream Mach numbers exceeding 1.3, the wedge probe sensitivity to velocity is always greater than its sensitivity to density over the entire flow regime. This property requires determination of three fluctuation components due to density, velocity, and temperature, in a transonic or supersonic turbulent flow. Sensitivity equations are derived based on the observed behavior of the wedge probe. Both the durability and the frequency response of the probe are excellent, the square wave insertion test indicating frequency response near 130 kHz. The directional response of the probe at sonic speed is poor and requires further examination before Reynolds stress measurements are attempted with dual sensor probes.

  1. Stratified Turbulence Measurements in Complex Terrain Using Hot-film Probes and a Collocated Sonic Anemometer

    NASA Astrophysics Data System (ADS)

    Hocut, C.; Kit, E.; Liberzon, D.; Fernando, H. J. S.; Materhorn Team

    2014-11-01

    In the fall of 2012 and spring 2013, the Mountain Terrain Atmospheric Modeling and Observations Program (MATERHORN) conducted extensive field experiments at the Granite Mountain Atmospheric Science Testbed (GMAST), US Army Dugway Proving Grounds (DPG), Utah. This provided a unique opportunity to deploy tower mounted three-dimensional hot-film combo probes, consisting of sonic anemometers collocated with hot-film anemometers able to respond to the wind direction. The combo probes follow mean winds using a feedback control loop and use a Neural Network to calibrate the hot-films in-situ. Once calibrated, these probes can handle a vast range of background flow conditions and scales from mesoscale flow down to the Kolmogorov scale. Of particular interest are the observed variation in velocity spectra during the evenings. Sometimes the velocity spectra shows the turbulence is Kolmogorov and is isotropic at small scales while in other spectra there is evidence of turbulence production at finer scales. An explanation on different spectral shapes will be presented as well as the relevant length/time scales of the production events. Funded by ONR Grant N00014-11-1-0709.

  2. The Analysis of Turbulent Flow by Hot Wire Signals. Ph.D. Thesis - Physikalische Ingenieurvissenschaft der Technischen Univ., 1981

    NASA Technical Reports Server (NTRS)

    Bartenwerfer, M.

    1982-01-01

    When measuring velocities in turbulent gas flow, approximation signal analysis with hot wire anemometers having one and two wire probes are used. A numeric test of standard analyses shows the resulting systemmatic error increases quickly with increasing turbulent intensity. Since it also depends on the turbulence structure, it cannot be corrected. The use of such probes is thus restricted to low turbulence. By means of three wire probes (in two dimensional flows with X wire probes) in principle, instantaneous values of velocity can be determined, and an asymmetric arrangement of wires has a theoretical advantage.

  3. Note: Signal conditioning of a hot-film anemometer for a periodic flow rate monitoring system.

    PubMed

    Mantovani, Federico; Tagliaferri, Cristian

    2011-12-01

    A flow monitoring system based on a constant temperature hot-film anemometer is presented. The device has been designed to monitor a dispensing process of extremely low quantities of adhesive material. The monitoring device presented in this paper is useful in industrial applications where exact flow speed tracking is not needed, but reliability and tolerance to parameters variability are essential. During the design of the device, problems related to the physical characteristic of the calorimetric sensor, in particular its thermal capacitance, and to the periodic nature of the monitored flow have been taken into account and suitable solutions have been implemented. The schematic representation of the monitoring device together with the experimental results obtained by monitoring fluids with different physical characteristics are presented.

  4. Calibration, Data Acquisition, and Post Analysis of Turbulent Fluid Flow in a Calibration Jet Using Hot-wire Anemometry

    NASA Technical Reports Server (NTRS)

    Moreno, Michelle

    2004-01-01

    The Turbine Branch concentrates on the following areas: Computational Fluid Dynamics (CFD), and implementing experimental procedures to obtain physical modeling data. Hot-wire Anemometry is a valuable tool for obtaining physical modeling data. Hot-wire Anemometry is likely to remain the principal research tool for most turbulent air/gas flow studies. The Hot-wire anemometer consists of a fine wire heated by electric current. When placed in a fluid stream, the hot-wire loses heat to the fluid by forced convection. In forced convection, energy transfer is due to molecular motion imposed by an extraneous force moving fluid parcels. When the hot-wire is in "equilibrium", the rate of heat input to the wire is equal to the rate of heat loss at the wire ends. The equality between heat input and heat loss is the basis for King s equation, which relates the electrical parameters of the hot-wire to the flow parameters of the fluid. Hot-wire anemometry is based on convective heat transfer from a heated wire element placed in a fluid flow. Any change in the fluid flow condition that affects the heat transfer from the heated element will be detected virtually instantaneously by a constant-temperature Hot-wire anemometry system. The system implemented for this research is the IFA 300. The system is a fully-integrated, thermal anemometer-based system that measures mean and fluctuating velocity components in air, water, and other fluids. It also measures turbulence and makes localized temperature measurements. A constant-temperature anemometer is a bridge and amplifier circuit that controls a tiny wire at constant temperature. As a fluid flow passes over the heated sensor, the amplifier senses the bridge off-balance and adjusts the voltage to the top of the bridge, keeping the bridge in balance. The voltage on top of the bridge can then be related to the velocity of the flow. The bridge voltage is sensitive to temperature as well as velocity and so the built-in thermocouple

  5. Hot-wire coil probe for high-speed flows

    NASA Technical Reports Server (NTRS)

    Weinstein, L. M.

    1973-01-01

    Small-diameter-wire coil probes developed for use in a hypersonic helium tunnel are discussed. The springlike properties of the coil minimize strain-gauge effects, and allow to use a higher length-to-diameter ratio for a given flow. In addition, the coil is more rugged for sudden flow changes, and since it can be mounted straight across the support tips, there is less support interference in cross flows. In addition to measuring fluctuating quantities in a boundary layer, the probes were used with a constant temperature anemometer for measuring mean mass flow profiles, and with a constant current anemometer for measuring mean total temperature profiles.

  6. Turbulence measurements in a complex plowfield using a crossed hot-wire. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Mckillop, B. E.

    1983-01-01

    Turbulence was quantified in complex axisymmetric, nonreacting, nonswirling flowfields using a crossed hot-wire anemometer. Mean velocity, turbulence intensities, turbulent viscosity, and Reynolds tree were measured in round free jet and confined jet flowfields. The confined jet, a model of an axisymmetric can combustor, had an expansion ratio D/d=2, an expansion angle of 90 deg, and an axial location increments of 0.5 diameters. The confined jet was studied with and without a contraction nozzle. Free jet measurements validated the experimental technique and data reduction. Results show good agreement with those of previous research. Measurements in the confined jet indicate that the cross hot-wire used cannot handle axial flow reversal and the experimental technique is inadequate for measuring time-mean radial velocity. Other quantities show a high level of comparability.

  7. The flying hot wire and related instrumentation

    NASA Technical Reports Server (NTRS)

    Coles, D.; Cantnell, B.; Wadcock, A.

    1978-01-01

    A flying hot-wire technique is proposed for studies of separated turbulent flow in wind tunnels. The technique avoids the problem of signal rectification in regions of high turbulence level by moving the probe rapidly through the flow on the end of a rotating arm. New problems which arise include control of effects of torque variation on rotor speed, avoidance of interference from the wake of the moving arms, and synchronization of data acquisition with rotation. Solutions for these problems are described. The self-calibrating feature of the technique is illustrated by a sample X-array calibration.

  8. Hot-wire anemometry in hypersonic helium flow

    NASA Technical Reports Server (NTRS)

    Wagner, R. D.; Weinstein, L. M.

    1974-01-01

    Hot-wire anemometry techniques are described that have been developed and used for hypersonic-helium-flow studies. The short run time available dictated certain innovations in applying conventional hot-wire techniques. Some examples are given to show the application of the techniques used. Modifications to conventional equipment are described, including probe modifications and probe heating controls.

  9. Hot-wire calibration in a nonisothermal incompressible pressure variant flow

    NASA Astrophysics Data System (ADS)

    Hugo, Ronald J.; Nowlin, Scott R.; Eaton, Frank D.; Bishop, Kenneth P.; McCrae, Kimberley A.

    1999-08-01

    The calibration procedure for a hot-wire anemometer system operating in a non-isothermal pressure-variant flow field is presented. Sensing of atmospheric velocity and temperature fluctuations from an altitude-variant platform using hot- wire anemometry equipment operating in both constant- temperature and constant-current modes requires calibration for velocity, temperature, and atmospheric pressure variations. Calibration tests to provide the range of velocity, temperature and pressure variations anticipated during Air Force Research Lab, Directed Energy Directorate- sponsored kite/tethered-balloon experiments were conducted and the result of these tests presented. The calibration tests were performed by placing the kite/tethered-balloon sensor package on a vehicle and driving from Kirtland AFB, NM to the top of Sandia Crest, a 10678 ft mountain range to the east of Albuquerque, NM. By varying the velocity of the van and conducting the test at different times of the day, variations in velocity, temperature and pressure within the range of those encountered during the kite/tethered-balloon experiments were obtained. The method of collapsing the calibration data is presented. Problems associated with collecting hot-wire anemometry data in a non-laboratory environment are discussed. Example data sets of temperature and velocity collected during the kite/tethered-balloon experiments are presented.

  10. Constant-Operating-Resistance Hot-Wire Probe

    NASA Technical Reports Server (NTRS)

    Stainback, P. C.

    1985-01-01

    Effects of lead-wire-resistance changes with temperature nullified. Constant-operating-resistance hot-wire probe uses two sets of leads. Exposed to identical conditions, comparison of resistance gives change in sensing element itself. Data taken in more convenient manner, with advantage of not having to constantly check for possible changes in lead resistance and consequently readjust potentiometer.

  11. Constant temperature hot wire anemometry data reduction procedure

    NASA Technical Reports Server (NTRS)

    Klopfer, G. H.

    1974-01-01

    The theory and data reduction procedure for constant temperature hot wire anemometry are presented. The procedure is valid for all Mach and Prandtl numbers, but limited to Reynolds numbers based on wire diameter between 0.1 and 300. The fluids are limited to gases which approximate ideal gas behavior. Losses due to radiation, free convection and conduction are included.

  12. Mars Acoustic Anemometer

    NASA Astrophysics Data System (ADS)

    Banfield, D. J.

    2012-12-01

    is far less susceptible to contaminating influences as other techniques (e.g., hot wire/hot film) that have been used for anemometry at Mars. Our instrument is conceptually derived from the commercial terrestrial sonic anemometers, but uses specialized acoustic transducers to optimally couple with the low density martian air as well as survive the extreme temperature swings on Mars. Additionally, we use sophisticated signal processing to extract as much information as possible in the low S/N environment that is achievable at Mars. We have developed our instrument through to TRL 5, proving it in a martian wind tunnel in Denmark. We found wind speed sensitivities and precision to be of order 3 cm/s, and with appropriate calibration, accuracy can be similar, even when operating at 20-100 Hz. We will also test this instrument at 120,000' altitude (i.e., equivalent to Mars atmospheric density) as an autonomous package on a stratospheric balloon. We are currently developing a TRL 6 version of the instrument that will be tested once again in the Denmark Mars Wind Tunnel. We expect our flight configuration instrument to be about 1 kg, including a 1.5m mast. It will also draw about 2-3W of power. This instrument is now ready to be proposed for future Mars missions, where we believe it will make a significant contribution and a step forward in Mars atmospheric science.

  13. Extrapolation of Calibration Curve of Hot-wire Spirometer Using a Novel Neural Network Based Approach.

    PubMed

    Ardekani, Mohammad Ali; Nafisi, Vahid Reza; Farhani, Foad

    2012-10-01

    Hot-wire spirometer is a kind of constant temperature anemometer (CTA). The working principle of CTA, used for the measurement of fluid velocity and flow turbulence, is based on convective heat transfer from a hot-wire sensor to a fluid being measured. The calibration curve of a CTA is nonlinear and cannot be easily extrapolated beyond its calibration range. Therefore, a method for extrapolation of CTA calibration curve will be of great practical application. In this paper, a novel approach based on the conventional neural network and self-organizing map (SOM) method has been proposed to extrapolate CTA calibration curve for measurement of velocity in the range 0.7-30 m/seconds. Results show that, using this approach for the extrapolation of the CTA calibration curve beyond its upper limit, the standard deviation is about -0.5%, which is acceptable in most cases. Moreover, this approach for the extrapolation of the CTA calibration curve below its lower limit produces standard deviation of about 4.5%, which is acceptable in spirometry applications. Finally, the standard deviation on the whole measurement range (0.7-30 m/s) is about 1.5%.

  14. Reusable Hot-Wire Cable Cutter

    NASA Technical Reports Server (NTRS)

    Pauken, Michael T.; Steinkraus, Joel M.

    2010-01-01

    During the early development stage of balloon deployment systems for missions, nichrome wire cable cutters were often used in place of pyro-actuated cutters. Typically, a nichrome wire is wrapped around a bundle of polymer cables with a low melting point and connected to a relay-actuated electric circuit. The heat from the nichrome reduces the strength of the cable bundle, which quickly breaks under a mechanical load and can thus be used as a release mechanism for a deployment system. However, the use of hand-made heated nichrome wire for cutters is not very reliable. Often, the wrapped nichrome wire does not cut through the cable because it either pulls away from its power source or does not stay in contact with the cable being cut. Because nichrome is not readily soldered to copper wire, unreliable mechanical crimps are often made to connect the nichrome to an electric circuit. A self-contained device that is reusable and reliable was developed to sever cables for device release or deployment. The nichrome wire in this new device is housed within an enclosure to prevent it from being damaged by handling. The electric power leads are internally connected within the unit to the nichrome wire using a screw terminal connection. A bayonet plug, a quick and secure method of connecting the cutter to the power source, is used to connect the cutter to the power leads similar to those used in pyro-cutter devices. A small ceramic tube [0.25-in. wide 0.5-in. long (.6.4-mm wide 13-mm long)] houses a spiraled nichrome wire that is heated when a cable release action is required. The wire is formed into a spiral coil by wrapping it around a mandrel. It is then laid inside the ceramic tube so that it fits closely to the inner surface of the tube. The ceramic tube provides some thermal and electrical insulation so that most of the heat generated by the wire is directed toward the cable bundle in the center of the spiral. The ceramic tube is cemented into an aluminum block, which

  15. Algorithm to optimize transient hot-wire thermal property measurement.

    PubMed

    Bran-Anleu, Gabriela; Lavine, Adrienne S; Wirz, Richard E; Kavehpour, H Pirouz

    2014-04-01

    The transient hot-wire method has been widely used to measure the thermal conductivity of fluids. The ideal working equation is based on the solution of the transient heat conduction equation for an infinite linear heat source assuming no natural convection or thermal end effects. In practice, the assumptions inherent in the model are only valid for a portion of the measurement time. In this study, an algorithm was developed to automatically select the proper data range from a transient hot-wire experiment. Numerical simulations of the experiment were used in order to validate the algorithm. The experimental results show that the developed algorithm can be used to improve the accuracy of thermal conductivity measurements.

  16. Influence of humidity on hot-wire measurements

    NASA Astrophysics Data System (ADS)

    Durst, Franz; Noppenberger, Stefan; Still, Martin; Venzke, Holger

    1996-10-01

    When applying hot-wire anemometry to velocity measurements in air, it is standard practice to neglect the effect of humidity. In this paper the influence of the thermodynamic and transport properties of humid air on hot-wire measurements is examined on the basis of the correlations for Nusselt number proposed previously by other researchers. Experimental results at controlled levels of relative humidity between 30% and 90% at 0957-0233/7/10/021/img1, 0957-0233/7/10/021/img2 and 0957-0233/7/10/021/img3 are reproduced satisfactorily by the theoretical approaches of two of these equations. A corrective term is defined to expand formulae designed for dry air to work in a humid environment. The error in velocity by omitting the influence of humidity is estimated in terms of temperature and relative humidity.

  17. ESR studies on hot-wire amorphous silicon

    SciTech Connect

    Unold, T.; Mahan, A.H.

    1997-07-01

    The authors measure a series of hot-wire (HW) amorphous silicon films grown with hydrogen contents C{sub H} varying between 0.5--17 at.%. From constant photocurrent method (CPM) measurements and the steady-state photocarrier grating method (SSPG) they find good agreement with previous measurements on similar hot-wire films. Electron spin resonance measurements on the same samples, however, yield significantly higher spin densities than expected. A thickness series indicates a highly defective layer close to the substrate interface. They propose that this defective layer may be due to excessive out diffusion of hydrogen during growth at high temperatures, as seen by secondary ion mass spectroscopy. ESR measurements on light-degraded samples indicate an improved stability of samples with C{sub H} < 9 at.%.

  18. Methods of Measurement of High Air Velocities by the Hot-wire Method

    NASA Technical Reports Server (NTRS)

    Weske, John R.

    1943-01-01

    Investigations of strengths of hot wires at high velocities were conducted with platinum, nickel, and tungsten at approximately 200 Degrees Celcius hot-wire temperature. The results appear to disqualify platinum for velocities approaching the sonic range; whereas nickel withstands sound velocity, and tungsten may be used for supersonic velocities under standard atmospheric conditions. Hot wires must be supported by rigid prolongs at high velocities to avoid wire breakage. Resting current measurements for constant temperature show agreement with King's relation.

  19. Hot-wire Laser Welding of Deep and Wide Gaps

    NASA Astrophysics Data System (ADS)

    Näsström, J.; Frostevarg, J.; Silver, T.

    Heavy section Gas Metal Arc Welding (GMAW) usually requires special edge preparation and several passes. One alternative for increased performance is Laser Arc Hybrid Welding (LAHW). For very thick sheets however, imperfections like root drops or solidification cracks can occur. In this study, other techniques are also studied, including multi-pass filling of deep gaps with wire deposition. A laser is then used to melt the filler and base material. The hot- and cold wire laser welding processes are highly sensitive to wire-laser positioning, where controlled melting of the wire is essential. Apart from a comprehensive literature survey, preliminary experiments were also performed in order to find a novel method variant that can successfully fill deep and wide gaps. The method applied uses a defocused laser that generates the melt pool. A resistance heated wire is fed into the melt pool front in a leading position. This is similar to additive manufacturing techniques such as laser direct metal deposition with wire. A layer height of several millimeters can be achieved and rather low laser power can be chosen. The preliminary experiments were observed using high speed imaging and briefly evaluated by visual examination of the resulting beads. Using a defocused laser beam turned out to have two major advantages; 1. It adds heat to the melt pool in a manner that properly fuses the bottom and walls of the base material. 2. It counteracts difficulties due to an irregularly oscillating filler wire. These early results show that this can be a promising technique for joining thick steels with wide gaps.

  20. Development of subminiature multi-sensor hot-wire probes

    NASA Technical Reports Server (NTRS)

    Westphal, Russell V.; Ligrani, Phillip M.; Lemos, Fred R.

    1988-01-01

    Limitations on the spatial resolution of multisensor hot wire probes have precluded accurate measurements of Reynolds stresses very near solid surfaces in wind tunnels and in many practical aerodynamic flows. The fabrication, calibration and qualification testing of very small single horizontal and X-array hot-wire probes which are intended to be used near solid boundaries in turbulent flows where length scales are particularly small, is described. Details of the sensor fabrication procedure are reported, along with information needed to successfully operate the probes. As compared with conventional probes, manufacture of the subminiature probes is more complex, requiring special equipment and careful handling. The subminiature probes tested were more fragile and shorter lived than conventional probes; they obeyed the same calibration laws but with slightly larger experimental uncertainty. In spite of these disadvantages, measurements of mean statistical quantities and spectra demonstrate the ability of the subminiature sensors to provide the measurements in the near wall region of turbulent boundary layers that are more accurate than conventional sized probes.

  1. Nanoscale Hot-Wire Probes for Boundary-Layer Flows

    NASA Technical Reports Server (NTRS)

    Tedjojuwono, Ken T.; Herring, Gregory C.

    2003-01-01

    Hot-wire probes having dimensions of the order of nanometers have been proposed for measuring temperatures (and possibly velocities) in boundary-layer flows at spatial resolutions much finer and distances from walls much smaller than have been possible heretofore. The achievable resolutions and minimum distances are expected to be of the order of tens of nanometers much less than a typical mean free path of a molecule and much less than the thickness of a typical flow boundary layer in air at standard temperature and pressure. An additional benefit of the small scale of these probes is that they would perturb the measured flows less than do larger probes. The hot-wire components of the probes would likely be made from semiconducting carbon nanotubes or ropes of such nanotubes. According to one design concept, a probe would comprise a single nanotube or rope of nanotubes laid out on the surface of an insulating substrate between two metallic wires. According to another design concept, a nanotube or rope of nanotubes would be electrically connected and held a short distance away from the substrate surface by stringing it between two metal electrodes. According to a third concept, a semiconducting nanotube or rope of nanotubes would be strung between the tips of two protruding electrodes made of fully conducting nanotubes or ropes of nanotubes. The figure depicts an array of such probes that could be used to gather data at several distances from a wall. It will be necessary to develop techniques for fabricating the probes. It will also be necessary to determine whether the probes will be strong enough to withstand the aerodynamic forces and impacts of micron-sized particles entrained in typical flows of interest.

  2. Wall proximity corrections for hot-wire readings in turbulent flows

    NASA Technical Reports Server (NTRS)

    Hebbar, K. S.

    1980-01-01

    This note describes some details of recent (successful) attempts of wall proximity corrections for hot-wire measurements performed in a three-dimensional incompressible turbulent boundary layer. A simple and quite satisfactory method of estimating wall proximity effects on hot-wire readings is suggested.

  3. Demonstration of skin friction measurements featuring in situ estimation of conduction loss using constant voltage anemometers and surface hot-films

    NASA Astrophysics Data System (ADS)

    Sarma, Garimella R.; Moes, Timothy R.

    2005-05-01

    The top of the 12.2m long NASA Dryden Flight Research Center's ground research vehicle (GRV) was used as a flat plate test bed for demonstrating an approach to measure skin friction. Using an array of surface hot-films operated by constant voltage anemometers (CVAs), the approach was demonstrated with in situ estimation of conduction heat loss from the hot-films to the substrate. An algebraic relationship, using the channel calibration constants a and b (determined a priori) with CVA output voltages Vs and Vw from that channel, is used for the estimation of the required quantities and lead resistance (rL) of the hot-film measured on site. Estimates of the power dissipated in the hot-film alone (Phf) (excluding the lead resistances), in situ resistance (Rw) of the hot-film due to applied overheat and flow, and the cold resistance (Ra) of the same hot-film at the ambient temperature are so obtained. Different approaches to estimate the in situ cold resistance (which is the resistance without any self-heating) of the hot-film are presented addressing the suitability of the procedure for flight applications as well. Tests were performed at several speeds of the GRV on the tarmac of a runway at the flight test center. The measured values are fitted to the classical (1/3) law equation with the computational dimensional skin friction (τ) obtained using the empirical local skin friction law for the long flat plate. There was an excellent (1/3) law fit in all the hot-films, demonstrating that the measured values fit classical theory. Using this measured fit with the theoretical values, calibration coefficients (A and B) for dimensional skin friction (τ) were obtained. Using these calibration coefficients, measured values were then converted to nondimensional local skin friction coefficients cf for all the hot-films at all speeds. Measured cf values agree well with the associated flat plate theory. Since the in situ measurement of heat loss to the substrate should ideally

  4. Hot wire deposited hydrogenated amorphous silicon solar cells

    SciTech Connect

    Mahan, A.H.; Iwaniczko, E.; Nelson, B.P.; Reedy, R.C. Jr.; Crandall, R.S.

    1996-05-01

    This paper details the results of a study in which low H content, high deposition rate hot wire (HW) deposited amorphous silicon (a-Si:H) has been incorporated into a substrate solar cell. The authors find that the treatment of the top surface of the HW i layer while it is being cooled from its high deposition temperature is crucial to device performance. They present data concerning these surface treatments, and correlate these treatments with Schottky device performance. The authors also present first generation HW n-i-p solar cell efficiency data, where a glow discharge (GD) {mu}c-Si(p) layer was added to complete the partial devices. No light trapping layer was used to increase the device Jsc. Their preliminary investigations have yielded efficiencies of up to 6.8% for a cell with a 4000 {Angstrom} thick HW i-layer, which degrade less than 10% after a 900 hour light soak. The authors suggest avenues for further improvement of their devices.

  5. a-Si:H Grown by Hot-Wire CVD at Ultra-High Deposition Rates

    SciTech Connect

    Xu, Y.; Nelson, B. P.; Mahan, A. H.; Williamson, D. L.; Crandall, R. S.; Iwaniczko, E.; Wang, Q.

    2000-01-01

    We increase the deposition rate of growing hydrogenated amorphous-silicon (a-Si:H) by the hot-wire chemical vapor depositon (HWCVD) technique by adding filaments (two) and decreasing the filament(s) to substrate distance.

  6. Development of a Martian Sonic Anemometer

    NASA Astrophysics Data System (ADS)

    Dissly, R. W.; Banfield, D. J.; Lasnik, J.; Waters, J. T.; McEwan, I. J.; Richardson, M. I.

    2005-08-01

    This presentation will describe the progress to-date on the development of an acoustic anemometer for the in-situ measurement of wind speeds on Mars, funded by NASA PIDDP. Improved measurements of Martian winds are needed for several reasons: better prediction and understanding of global and regional weather, direct measurement of fluxes between surface/atmosphere of momentum, heat, and trace atmospheric constituents, characterizing and monitoring boundary layer winds that influence the safe delivery of spacecraft to/from the Martian surface, and improved characterization of geologically important aeolian processes that can pose a hazard to future exploration via dust storms and dust devils. Prior attempts to measure surface winds have been limited in capability and difficult to calibrate. Sonic anemometry, measuring wind speed via sound pulse travel-time differences, can overcome many of these issues. Sonic anemometry has several distinct advantages over other methods such as hot wire techniques: higher sensitivity ( <5 cm/s), higher time resolution (10-100 Hz), and fewer intrinsic biases for improved accuracy. Together, these open the possibility of resolving turbulent boundary layer eddies to directly capture surface-to-atmospheric fluxes for the first time. We will describe the results of our development of an acoustic anemometer using capacitive micro-machined devices, optimized for acoustic coupling in a low-pressure medium like the Martian atmosphere. This development includes transducer characterization tests in a pressure chamber at Ball Aerospace with Mars-relevant CO2 pressures. We will also describe experimental results showing that the addition of water in a low-pressure CO2 atmosphere can significantly increase acoustic attenuation. Finally we will describe plans for further optimization of the instrument for future Mars payloads.

  7. Basic ideas and concepts in hot wire anemometry: an experimental approach for introductory physics students

    NASA Astrophysics Data System (ADS)

    El Abed, Mohamed

    2016-01-01

    The purpose of hot wire anemometry is to measure the speed of an air stream. The classical method is based on the measure of the value of a temperature dependant resistor inserted in a Wheatstone bridge (Lomas 1986 Fundamentals of Hot Wire Anemometry (Cambridge: Cambridge University Press)). In this paper we exhibit the physics behind this method and show that by using a wire whose resistance does not vary on the field of temperature explored (from 20 °C to 200 °C), it is however possible to make accurate measurements. Finally, limitations of the method are discussed.

  8. Pitfalls of hot-wire probes for a new method of dissipation evaluation

    NASA Astrophysics Data System (ADS)

    Turan, O.; Azad, R. S.

    A new method of obtaining dissipation with hot-wire anemometry has been introduced recently by Azad et al. (1985, 1986). The method is based on extrapolation to zero wire length of the dissipation rate measured with hot-wire probes of different lengths. The present study has been undertaken to examine this method in detail. It has been observed in the present study that there are two major pitfalls in extrapolating dissipation to zero wire length. The first is due to the length to diameter ratio, L/d of the probes used. The second pitfall is due to defects in the probe structure. Spatial filtering due to wire length in the measurement of dissipation has been confirmed to be linear provided probes with L/d of greater than 160 are free of structural defects. The method can be used advantageously to detect such defective probes.

  9. A hot-wire method for high-intensity turbulent flows

    NASA Technical Reports Server (NTRS)

    Mueller, U. R.

    1983-01-01

    A measuring technique for determing instantaneous, three-dimensional velocity vectors in highly turbulent flows by means of a 4-sensor hot-wire probe is described. As is well known, the hot-wire signal received in reversing flows cannot uniquely be interpreted. This difficulty is circumvented by tracking the thermal wake of a heated wire. Whenever the approximate flow direction is indicated by a temperature-sensitive wake detector, all components of the instantaneous velocity vector are evaluated by means of a digital data reduction method. Uniqueness of the solution derived from the triple-hot-wire response equations is examined. A first application of the proposed measuring technique in the recirculating flow downstream of a backward-facing step is described.

  10. All-optical fiber anemometer based on laser heated fiber Bragg gratings.

    PubMed

    Gao, Shaorui; Zhang, A Ping; Tam, Hwa-Yaw; Cho, L H; Lu, Chao

    2011-05-23

    A fiber-optic anemometer based on fiber Bragg gratings (FBGs) is presented. A short section of cobalt-doped fiber was utilized to make a fiber-based "hot wire" for wind speed measurement. Fiber Bragg gratings (FBGs) were fabricated in the cobalt-doped fiber using 193 nm laser pulses to serve as localized temperature sensors. A miniature all-optical fiber anemometer is constructed by using two FBGs to determine the dynamic thermal equilibrium between the laser heating and air flow cooling through monitoring the FBGs' central wavelengths. It was demonstrated that the sensitivity of the sensor can be adjusted through the power of pump laser or the coating on the FBG. Experimental results reveal that the proposed FBG-based anemometer exhibits very good performance for wind speed measurement. The resolution of the FBG-based anemometer is about 0.012 m/s for wind speed range between 2.0 m/s and 8.0 m/s.

  11. Synthesis of silicon nanowires using tin catalyst by hot wire chemical vapor processing

    SciTech Connect

    Meshram, Nagsen; Kumbhar, Alka; Dusane, R.O.

    2013-06-01

    Highlights: ► Silicon nanowires are grown by hot wire chemical vapor processing at 400 °C using Sn as catalyst material via VLS. ► For nanowire synthesis Sn nanotemplates are formed with hot wire generated atomic hydrogen. ► The TEM image reveals the crystalline nature of nanowire. - Abstract: Silicon nanowires (SiNWs) have been synthesized at temperatures in the range 300–400 °C by the hot wire chemical vapor processing (HWCVP) using tin nanotemplate. The tin nano-template is formed by hot wire atomic hydrogen treatment of thermally evaporated Sn films (∼300 nm thick) on glass substrates. Silicon nanowires are then grown using hot wire induced dissociation of SiH{sub 4} gas over the nanotemplate. Growth conditions like growth time and temperature were varied to study their effect on the tin nanoparticle size and on the silicon nanowire dimensions thereafter. From the observations, it is clear that the nanowire diameters and lengths depend on the size of nanoparticles and the growth time respectively. Though SiNWs were observed to grow at temperatures as low as 300 °C, nanowires with a narrow diameter distribution were achieved at 400 °C. Raman spectra and transmission electron microscope (TEM) reveal the crystalline nature of the silicon nanowires.

  12. Basic study on hot-wire flow meter in forced flow of liquid hydrogen

    NASA Astrophysics Data System (ADS)

    Oura, Y.; Shirai, Y.; Shiotsu, M.; Murakami, K.; Tatsumoto, H.; Naruo, Y.; Nonaka, S.; Kobayashi, H.; Inatani, Y.; Narita, N.

    2014-01-01

    Liquid hydrogen (LH2) is a key issue in a carbon-free energy infrastructure at the energy storage and transportation stage. The typical features of LH2 are low viscosity, large latent heat and small density, compared with other general liquids. It is necessary to measure a mass flow of liquid hydrogen with a simple and compact method, especially in a two phase separate flow condition. We have proposed applying a hot-wire type flow meter, which is usually used a for gas flow meter, to LH2 flow due to the quite low viscosity and density. A test model of a compact LH2 hot-wire flow meter to measure local flow velocities near and around an inside perimeter of a horizontal tube by resistance thermometry was designed and made. The model flow meter consists of two thin heater wires made of manganin fixed in a 10 mm-diameter and 40 mm-length tube flow path made of GFRP. Each rigid heater wire was set twisted by 90 degrees from the inlet to the outlet along the inner wall. In other words, the wires were aslant with regard to the LH2 stream line. The heated wire was cooled by flowing LH2, and the flow velocity was obtained by means of the difference of the cooling characteristic in response to the flow velocity. In this report, we show results on the basic experiments with the model LH2 hot-wire flow meter. First, the heat transfer characteristics of the two heater wires for several LH2 flow velocities were measured. Second, the heating current was controlled to keep the wire temperature constant for various flow velocities. The relations between the flow velocity and the heating current were measured. The feasibility of the proposed model was confirmed.

  13. All-Hot-Wire Chemical Vapor Deposition a-Si:H Solar Cells

    SciTech Connect

    Iwaniczko, E.; Wang, Q.; Xu, Y.; Nelson, B. P.; Mahan, A. H.; Crandall, R. S.; Branz, H. M.

    2000-01-01

    Efficient hydrogenated amorphous silicon (a-Si:H) nip solar cells have been fabricated with all doped and undoped a-Si:H layers deposited by hot-wire chemical vapor deposition (HWCVD). The total deposition time of all layers, except the top ITO-contact, is less than 4 minutes.

  14. Low temperature junction growth using hot-wire chemical vapor deposition

    DOEpatents

    Wang, Qi; Page, Matthew; Iwaniczko, Eugene; Wang, Tihu; Yan, Yanfa

    2014-02-04

    A system and a process for forming a semi-conductor device, and solar cells (10) formed thereby. The process includes preparing a substrate (12) for deposition of a junction layer (14); forming the junction layer (14) on the substrate (12) using hot wire chemical vapor deposition; and, finishing the semi-conductor device.

  15. A Hot-Wire Method Based Thermal Conductivity Measurement Apparatus for Teaching Purposes

    ERIC Educational Resources Information Center

    Alvarado, S.; Marin, E.; Juarez, A. G.; Calderon, A.; Ivanov, R.

    2012-01-01

    The implementation of an automated system based on the hot-wire technique is described for the measurement of the thermal conductivity of liquids using equipment easily available in modern physics laboratories at high schools and universities (basically a precision current source and a voltage meter, a data acquisition card, a personal computer…

  16. Transport of high intensity laser-generated hot electrons in cone coupled wire targets

    NASA Astrophysics Data System (ADS)

    Beg, Farhat

    2008-04-01

    In this talk, we present results from a series of experiments where cone-wire targets were employed both to assess hot electron coupling efficiency, and to reveal the source temperature of the hot electrons. Experiments were performed on the petawatt laser at the Rutherford Appleton Laboratory. A 500J, 1ps laser (I ˜ 4 x 10^20 W/cm-2) was focused by an f/3 off-axis parabolic mirror into hollow aluminum cones joined at their tip to Cu wires of diameters from 10 to 40 μm. The three main diagnostics fielded were a copper Kalpha Bragg crystal imager, a single hit CCD camera spectrometer and a Highly Oriented Pyrolytic Graphite (HOPG) spectrometer. The resulting data were cross-calibrated to obtain the absolute Kalpha yield. Comparison of the axially diminishing absolute Cu Kα intensity with modeling shows that the penetration of the hot electrons is consistent with one dimensional ohmic potential limited transport (1/e length ˜ 100 μm). The laser coupling efficiency to electron energy within the wire is shown to be proportional to the cross sectional area of the wire, reaching 15% for 40 μm wires. We find that the hot electron temperature within the wire was <=750 keV, significantly lower than that predicted by the ponderomotive scaling. A comparison of the experimental results with 2D hybrid PIC simulations using e-PLAS code will be presented and relevance to Fast Ignition will be discussed at the meeting. *In collaboration with J.A. King, M.H. Key, K.U. Akli, R.R. Freeman, J. Green, S. P. Hatchett, D. Hey, P. Jaanimagi, J. Koch, K. L. Lancaster, T. Ma, A.J. MacKinnon, A. MacPhee, R. Mason, P.A. Norreys, P.K Patel, T. Phillips, R. Stephens, W. Theobald, R.P.J. Town, M. Wei, L. Van Woerkom, B. Zhang.

  17. Studies of Hot Spots in Imploding Wire Arrays at 1 MA on COBRA

    SciTech Connect

    Pikuz, Sergey A.; Shelkovenko, Tatiana A.; McBride, Ryan D.; Hammer, David A.

    2009-01-21

    We present recent results from hot spot investigations in imploding Al wire array z-pinches on the COBRA generator at Cornell University using x-ray diagnostics. Measurements of the temporal and spatial distribution of hot spots in stagnating plasmas by an x-ray streak-camera are included. Experiments show that hot spots have nanosecond lifetime and appear randomly along the array axis after plasma stagnation in secondary pinches in 8 mm diameter and during plasma stagnation in the arrays with 4 mm diameter.

  18. Formation quality optimization of laser hot wire cladding for repairing martensite precipitation hardening stainless steel

    NASA Astrophysics Data System (ADS)

    Wen, Peng; Feng, Zhenhua; Zheng, Shiqing

    2015-01-01

    Laser cladding is an advantaged repairing technology due to its low heat input and high flexibility. With preheating wire by resistance heat, laser hot wire cladding shows better process stability and higher deposition efficiency compared to laser cold wire/powder cladding. Multi-pass layer were cladded on the surface of martensite precipitation hardening stainless steel FV520B by fiber laser with ER410NiMo wire. Wire feed rate and preheat current were optimized to obtain stable wire transfer, which guaranteed good formation quality of single pass cladding. Response surface methodology (RSM) was used to optimize processing parameters and predict formation quality of multi-pass cladding. Laser power P, scanning speed Vs, wire feed rate Vf and overlap ratio η were selected as the input variables, while flatness ratio, dilution and incomplete fusion value as the responses. Optimal clad layer with flat surface, low dilution and no incomplete fusion was obtained by appropriately reducing Vf, and increasing P, Vs and η. No defect like pore or crack was found. The tensile strength and impact toughness of the clad layer is respectively 96% and 86% of those of the substrate. The clad layer showed nonuniform microstructure and was divided into quenched areas with coarse lath martensite and tempered areas with tempered martensite due to different thermal cycles in adjacent areas. The tempered areas showed similar hardness to the substrate.

  19. Hot wire needle probe for thermal conductivity detection

    SciTech Connect

    Condie, Keith Glenn; Rempe, Joy Lynn; Knudson, Darrell lee; Daw, Joshua Earl; Wilkins, Steven Curtis; Fox, Brandon S.; Heng, Ban

    2015-11-10

    An apparatus comprising a needle probe comprising a sheath, a heating element, a temperature sensor, and electrical insulation that allows thermal conductivity to be measured in extreme environments, such as in high-temperature irradiation testing. The heating element is contained within the sheath and is electrically conductive. In an embodiment, the heating element is a wire capable of being joule heated when an electrical current is applied. The temperature sensor is contained within the sheath, electrically insulated from the heating element and the sheath. The electrical insulation electrically insulates the sheath, heating element and temperature sensor. The electrical insulation fills the sheath having electrical resistance capable of preventing electrical conduction between the sheath, heating element, and temperature sensor. The control system is connected to the heating element and the temperature sensor.

  20. Process improvement in laser hot wire cladding for martensitic stainless steel based on the Taguchi method

    NASA Astrophysics Data System (ADS)

    Huang, Zilin; Wang, Gang; Wei, Shaopeng; Li, Changhong; Rong, Yiming

    2016-09-01

    Laser hot wire cladding, with the prominent features of low heat input, high energy efficiency, and high precision, is widely used for remanufacturing metal parts. The cladding process, however, needs to be improved by using a quantitative method. In this work, volumetric defect ratio was proposed as the criterion to describe the integrity of forming quality for cladding layers. Laser deposition experiments with FV520B, one of martensitic stainless steels, were designed by using the Taguchi method. Four process variables, namely, laser power ( P), scanning speed ( V s), wire feed rate ( V f), and wire current ( I), were optimized based on the analysis of signal-to-noise (S/N) ratio. Metallurgic observation of cladding layer was conducted to compare the forming quality and to validate the analysis method. A stable and continuous process with the optimum parameter combination produced uniform microstructure with minimal defects and cracks, which resulted in a good metallurgical bonding interface.

  1. Process improvement in laser hot wire cladding for martensitic stainless steel based on the Taguchi method

    NASA Astrophysics Data System (ADS)

    Huang, Zilin; Wang, Gang; Wei, Shaopeng; Li, Changhong; Rong, Yiming

    2016-07-01

    Laser hot wire cladding, with the prominent features of low heat input, high energy efficiency, and high precision, is widely used for remanufacturing metal parts. The cladding process, however, needs to be improved by using a quantitative method. In this work, volumetric defect ratio was proposed as the criterion to describe the integrity of forming quality for cladding layers. Laser deposition experiments with FV520B, one of martensitic stainless steels, were designed by using the Taguchi method. Four process variables, namely, laser power (P), scanning speed (V s), wire feed rate (V f), and wire current (I), were optimized based on the analysis of signal-to-noise (S/N) ratio. Metallurgic observation of cladding layer was conducted to compare the forming quality and to validate the analysis method. A stable and continuous process with the optimum parameter combination produced uniform microstructure with minimal defects and cracks, which resulted in a good metallurgical bonding interface.

  2. Correcting hot-wire measurements of stream-wise turbulence intensity in boundary layers

    SciTech Connect

    Monkewitz, P. A.; Duncan, R. D.; Nagib, H. M.

    2010-09-15

    The current experimental activity aimed at resolving the scaling of stream-wise turbulence intensity profiles uu{sup +}(y{sup +}) with Reynolds number in turbulent flat plate boundary layers has brought the largely unresolved issue of correcting systematic errors in hot-wire measurements of uu{sup +}(y{sup +}) into focus. Here, a heuristic scheme is proposed to generate unique uu{sup +}(y{sup +};Re{sub {delta}{sup *}}) profiles from data obtained with single hot wires of widely different length, aspect ratio and construction over a large Reynolds number range of 4000 < or approx. Re{sub {delta}{sup *}} < or approx. 50 000. A comparison with LDA data and other checks suggest that the present correction scheme produces uu{sup +}(y{sup +};Re{sub {delta}{sup *}}) profiles close to the (unknown) true profiles.

  3. Thermal conductivity measurement in clay dominant consolidated material by Transient Hot-Wire method.

    NASA Astrophysics Data System (ADS)

    Garnier, J. P.; Gallier, J.; Mercx, B.; Dudoignon, P.; Milcent, D.

    2010-06-01

    The transient hot-wire (THW) technique is widely used for measurements of the thermal-conductivity of most fluids and some attempts have also been carried out for simultaneous measurements of the thermal-diffusivity with the same hot wire. This technique was also tried to determine thermal properties of soils by the mean of probes which can be considered as wire with some assumptions. The purpose of this paper is to validate the thermal conductivity measurement by the THW technique in geomaterials, composed of compacted sand + clay mineral that can be used for earth construction (Compacted Earth Brick). The thermal transfer behaviors are mainly governed by the texture and moisture of the geomaterials. Thus the investigations were performed (1) in media made of glass beads of different diameters in dry and saturated state in order to observe the role of grain sizes and saturation state on the wire temperature (Δt) measurements and (2) in the compacted clay-geomaterial at different moisture states. The Δt / ln(t) diagrams allow the calculation of two thermal conductivities. The first one, measured in the short time acquisition (< 1s), characterizes the microtexture of the material and its hydrated state. The second one, measured for longer time acquisitions, characterizes the mean thermal conductivity of the material.

  4. Improvements of a nano-scale crossed hot-wire for high Reynolds number measurements

    NASA Astrophysics Data System (ADS)

    Fan, Yuyang; Hultmark, Marcus

    2015-11-01

    Hot-wire anemometry, despite its limited spatial and temporal resolution, is still the preferred tool for high Reynolds number flow measurements, mainly due to the continuous signal. To address the resolution issues, the Nano-Scale Thermal Anemometry Probe (NSTAP) was developed at Princeton University. The NSTAP has a sensing volume more than one order of magnitude smaller than conventional hot-wires, and it has displayed superior performance. However, the NSTAP can only measure a single component of the velocity. Using a novel combining method, a probe that enables two-component velocity measurements has been created (the x-NSTAP). The measurement volume is approximately 50 × 50 × 50 μ m, more than one order of magnitude smaller in all directions compared to conventional crossed hot-wires. The x-NSTAP has been further improved to allow more accurate measurements with the help of flow visualization using a scaled model but matching Reynolds number. Results from turbulent flow measurements with the new x-NSTAP are also presented. Supported under NSF grant CBET-1510100 (program manager Dimitrios Papavassiliou).

  5. A Martian acoustic anemometer.

    PubMed

    Banfield, Don; Schindel, David W; Tarr, Steve; Dissly, Richard W

    2016-08-01

    An acoustic anemometer for use on Mars has been developed. To understand the processes that control the interaction between surface and atmosphere on Mars, not only the mean winds, but also the turbulent boundary layer, the fluxes of momentum, heat and molecular constituents between surface and atmosphere must be measured. Terrestrially this is done with acoustic anemometers, but the low density atmosphere on Mars makes it challenging to adapt such an instrument for use on Mars. This has been achieved using capacitive transducers and pulse compression, and was successfully demonstrated on a stratospheric balloon (simulating the Martian environment) and in a dedicated Mars Wind Tunnel facility. This instrument achieves a measurement accuracy of ∼5 cm/s with an update rate of >20 Hz under Martian conditions. PMID:27586767

  6. Thermal Remote Anemometer Device

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.; Heath, D. Michele; Winfree, William P.; Miller, William E.; Welch, Christopher S.

    1988-01-01

    Thermal Remote Anemometer Device developed for remote, noncontacting, passive measurement of thermal properties of sample. Model heated locally by scanning laser beam and cooled by wind in tunnel. Thermal image of model analyzed to deduce pattern of airflow around model. For materials applications, system used for evaluation of thin films and determination of thermal diffusivity and adhesive-layer contact. For medical applications, measures perfusion through skin to characterize blood flow and used to determine viabilities of grafts and to characterize tissues.

  7. Generation and Transport of Hot Electrons in Cone-Wire Targets

    NASA Astrophysics Data System (ADS)

    Beg, Farhat

    2009-11-01

    We present results from a series of experiments where cone-wire targets in various configurations were employed both to assess hot electron coupling efficiency, and to reveal the source temperature of the hot electrons. Initial experiments were performed on the Vulcan petawatt laser at the Rutherford Appleton Laboratory and Titan laser at the Lawrence Livermore National Laboratory. Results with aluminum cones joined to Cu wires of diameters from 10 to 40 μm show that the laser coupling efficiency to electron energy within the wire is proportional to the cross sectional area of the wire. In addition, coupling into the wire was observed to decrease with the laser prepulse and cone-wall thickness. More recently, this study was extended, using the OMEGA EP laser. The resulting changes in coupling energy give indications of the scaling as we approach FI-relevant conditions. Requirements for FI scale fast ignition cone parameters: tip thickness, wall thickness, laser prepulse and laser pulse length, will be discussed. In collaboration with T. Yabuuchi, T. Ma, D. Higginson, H. Sawada, J. King, M.H. Key, K.U. Akli, Al Elsholz, D. Batani, H. Chen, R.R. Freeman, L. Gizzi, J. Green, S. Hatchett, D. Hey, P. Jaanimagi, J. Koch, K. L. Lancaster, D.Larson, A.J. MacKinnon, H. McLean, A. MacPhee, P.A. Norreys, P.K Patel, R. B. Stephens, W. Theobald, R. Town, M. Wei, S. Wilks, Roger Van Maren, B. Westover and L. VanWoerkom.

  8. A Thermal Analysis of a Hot-Wire Probe for Icing Applications

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Rigby, David L.; Venkataraman, Krishna

    2014-01-01

    This paper presents a steady-state thermal model of a hot-wire instrument applicable to atmospheric measurement of water content in clouds. In this application, the power required to maintain the wire at a given temperature is used to deduce the water content of the cloud. The model considers electrical resistive heating, axial conduction, convection to the flow, radiation to the surroundings, as well as energy loss due to the heating, melting, and evaporation of impinging liquid and or ice. All of these parameters can be varied axially along the wire. The model further introduces a parameter called the evaporation potential which locally gauges the maximum fraction of incoming water that evaporates. The primary outputs of the model are the steady-state power required to maintain a spatially-average constant temperature as well as the variation of that temperature and other parameters along the wire. The model is used to understand the sensitivity of the hot-wire performance to various flow and boundary conditions including a detailed comparison of dry air and wet (i.e. cloud-on) conditions. The steady-state power values are compared to experimental results from a Science Engineering Associates (SEA) Multi-Element probe, a commonly used water-content measurement instrument. The model results show good agreement with experiment for both dry and cloud-on conditions with liquid water content. For ice, the experimental measurements under read the actual water content due to incomplete evaporation and splashing. Model results, which account for incomplete evaporation, are still higher than experimental results where the discrepancy is attributed to splashing mass-loss which is not accounted in the model.

  9. Calibration and Measurement in Turbulence Research by the Hot-Wire Method

    NASA Technical Reports Server (NTRS)

    Kovasznay, Kaszlo

    1947-01-01

    The problem of turbulence in aerodynamics is at present being attacked both theoretically and experimentally. In view of the fact however that purely theoretical considerations have not thus far led to satisfactory results the experimental treatment of the problem is of great importance. Among the different measuring procedures the hot wire methods are so far recognized as the most suitable for investigating the turbulence structure. The several disadvantages of these methods however, in particular those arising from the temperature lag of the wire can greatly impair the measurements and may easily render questionable the entire value of the experiment. The name turbulence is applied to that flow condition in which at any point of the stream the magnitude and direction of the velocity fluctuate arbitrarily about a well definable mean value. This fluctuation imparts a certain whirling characteristic to the flow.

  10. Thermal transient anemometer

    DOEpatents

    Bailey, James L.; Vresk, Josip

    1989-01-01

    A thermal transient anemometer having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe.

  11. Thermal transient anemometer

    DOEpatents

    Bailey, J.L.; Vresk, J.

    1989-07-18

    A thermal transient anemometer is disclosed having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe. 12 figs.

  12. Heat transfer monitoring by means of the hot wire technique and finite element analysis software.

    PubMed

    Hernández Wong, J; Suarez, V; Guarachi, J; Calderón, A; Rojas-Trigos, J B; Juárez, A G; Marín, E

    2014-01-01

    It is reported the study of the radial heat transfer in a homogeneous and isotropic substance with a heat linear source in its axial axis. For this purpose, the hot wire characterization technique has been used, in order to obtain the temperature distribution as a function of radial distance from the axial axis and time exposure. Also, the solution of the transient heat transport equation for this problem was obtained under appropriate boundary conditions, by means of finite element technique. A comparison between experimental, conventional theoretical model and numerical simulated results is done to demonstrate the utility of the finite element analysis simulation methodology in the investigation of the thermal response of substances.

  13. Flow distribution in a roller jet bit determined from hot-wire anemometry measurements

    SciTech Connect

    Gavignet, A.A.; Bradbury, L.J.; Quetier, F.P.

    1987-03-01

    In current practice, the optimization of drilling hydraulics consists of the selection of nozzle sizes that maximize either jet impact or hydraulic power at the nozzle. But what is required for a real optimization is the knowledge of the hydraulic forces available for cleaning at the rock face, not at the nozzle. This paper shows the results of hot-wire anemometry experiments that provide insight into the flow distribution in a jet bit. Direct measurements of the flow field, including turbulence levels, are reported and discussed.

  14. Hot-Wire CVD Amorphous Si Materials for Solar Cell Application

    SciTech Connect

    Wang, Q.

    2009-01-01

    Hydrogenated amorphous silicon (a-Si:H) thin films and their application to solar cells fabricated using the hot-wire chemical vapor deposition (HWCVD) or (CAT)-CVD will be reviewed. This review will focus on the comparison to the standard plasma enhance (PE) CVD in the terms of deposition technique, film properties, and solar cell performance. The advantages of using HWCVD for a-Si:H solar cell research as well as the criteria for industry's adaptation of this technique for mass production will be addressed.

  15. Rotating hot-wire investigation of the vortex responsible for blade-vortex interaction noise

    NASA Technical Reports Server (NTRS)

    Fontana, Richard Remo

    1988-01-01

    This distribution of the circumferential velocity of the vortex responsible for blade-vortex interaction noise was measured using a rotating hot-wire rake synchronously meshed with a model helicopter rotor at the blade passage frequency. Simultaneous far-field acoustic data and blade differential pressure measurements were obtained. Results show that the shape of the measured far-field acoustic blade-vortex interaction signature depends on the blade-vortex interaction geometry. The experimental results are compared with the Widnall-Wolf model for blade-vortex interaction noise.

  16. Deposition of thermal and hot-wire chemical vapor deposition copper thin films on patterned substrates.

    PubMed

    Papadimitropoulos, G; Davazoglou, D

    2011-09-01

    In this work we study the hot-wire chemical vapor deposition (HWCVD) of copper films on blanket and patterned substrates at high filament temperatures. A vertical chemical vapor deposition reactor was used in which the chemical reactions were assisted by a tungsten filament heated at 650 degrees C. Hexafluoroacetylacetonate Cu(I) trimethylvinylsilane (CupraSelect) vapors were used, directly injected into the reactor with the aid of a liquid injection system using N2 as carrier gas. Copper thin films grown also by thermal and hot-wire CVD. The substrates used were oxidized silicon wafers on which trenches with dimensions of the order of 500 nm were formed and subsequently covered with LPCVD W. HWCVD copper thin films grown at filament temperature of 650 degrees C showed higher growth rates compared to the thermally ones. They also exhibited higher resistivities than thermal and HWCVD films grown at lower filament temperatures. Thermally grown Cu films have very uniform deposition leading to full coverage of the patterned substrates while the HWCVD films exhibited a tendency to vertical growth, thereby creating gaps and incomplete step coverage. PMID:22097561

  17. Microfluidic flowmeter based on micro "hot-wire" sandwiched Fabry-Perot interferometer.

    PubMed

    Li, Ying; Yan, Guofeng; Zhang, Liang; He, Sailing

    2015-04-01

    We present a compact microfluidic flowmeter based on Fabry-Perot interferometer (FPI). The FPI was composed by a pair of fiber Bragg grating reflectors and a micro Co(2+)-doped optical fiber cavity, acting as a "hot-wire" sensor. Microfluidic channels made from commercial silica capillaries were integrated with the FPIs on a chip to realize flow-rate sensing system. By utilizing a tunable pump laser with wavelength of 1480 nm, the proposed flowmeter was experimentally demonstrated. The flow rate of the liquid sample is determined by the induced resonance wavelength shift of the FPI. The effect of the pump power, microfluidic channel scale and temperature on the performance of our flowmeter was investigated. The dynamic response was also measured under different flow-rate conditions. The experimental results achieve a sensitivity of 70 pm/(μL/s), a dynamic range up to 1.1 μL/s and response time in the level of seconds, with a spatial resolution ~200 μm. Such good performance renders the sensor a promising supplementary component in microfluidic biochemical sensing system. Furthermore, simulation modal was built up to analyze the heat distribution of the "hot-wire" cavity and optimize the FPI structure as well.

  18. Kinetic study on hot-wire-assisted atomic layer deposition of nickel thin films

    SciTech Connect

    Yuan, Guangjie Shimizu, Hideharu; Momose, Takeshi; Shimogaki, Yukihiro

    2014-01-15

    High-purity Ni films were deposited using hot-wire-assisted atomic layer deposition (HW-ALD) at deposition temperatures of 175, 250, and 350 °C. Negligible amount of nitrogen or carbon contamination was detected, even though the authors used NH{sub 2} radical as the reducing agent and nickelocene as the precursor. NH{sub 2} radicals were generated by the thermal decomposition of NH{sub 3} with the assist of HW and used to reduce the adsorbed metal growth precursors. To understand and improve the deposition process, the kinetics of HW-ALD were analyzed using a Langmuir-type model. Unlike remote-plasma-enhanced atomic layer deposition, HW-ALD does not lead to plasma-induced damage. This is a significant advantage, because the authors can supply sufficient NH{sub 2} radicals to deposit high-purity metallic films by adjusting the distance between the hot wire and the substrate. NH{sub 2} radicals have a short lifetime, and it was important to use a short distance between the radical generation site and substrate. Furthermore, the impurity content of the nickel films was independent of the deposition temperature, which is evidence of the temperature-independent nature of the NH{sub 2} radical flux and the reactivity of the NH{sub 2} radicals.

  19. Microfluidic flowmeter based on micro "hot-wire" sandwiched Fabry-Perot interferometer.

    PubMed

    Li, Ying; Yan, Guofeng; Zhang, Liang; He, Sailing

    2015-04-01

    We present a compact microfluidic flowmeter based on Fabry-Perot interferometer (FPI). The FPI was composed by a pair of fiber Bragg grating reflectors and a micro Co(2+)-doped optical fiber cavity, acting as a "hot-wire" sensor. Microfluidic channels made from commercial silica capillaries were integrated with the FPIs on a chip to realize flow-rate sensing system. By utilizing a tunable pump laser with wavelength of 1480 nm, the proposed flowmeter was experimentally demonstrated. The flow rate of the liquid sample is determined by the induced resonance wavelength shift of the FPI. The effect of the pump power, microfluidic channel scale and temperature on the performance of our flowmeter was investigated. The dynamic response was also measured under different flow-rate conditions. The experimental results achieve a sensitivity of 70 pm/(μL/s), a dynamic range up to 1.1 μL/s and response time in the level of seconds, with a spatial resolution ~200 μm. Such good performance renders the sensor a promising supplementary component in microfluidic biochemical sensing system. Furthermore, simulation modal was built up to analyze the heat distribution of the "hot-wire" cavity and optimize the FPI structure as well. PMID:25968776

  20. High-impedance wire grid method to study spatiotemporal behavior of hot electron clump generated in a plasma

    SciTech Connect

    Terasaka, K. Kato, Y.; Tanaka, M. Y.; Yoshimura, S.; Morisaki, T.; Furuta, K.; Aramaki, M.

    2014-11-15

    High-impedance Wire Grid (HIWG) detector has been developed to study spatiotemporal behavior of a hot electron clump generated in an electron cyclotron resonance (ECR) plasma. By measuring the floating potentials of the wire electrodes, and generating structure matrix made of geometrical means of the floating potentials, the HIWG detector reconstructs the spatial distribution of high-temperature electron clump at an arbitrary instant of time. Time slices of the spike event in floating potential revealed the growth and decay process of a hot spot occurs in an ECR plasma.

  1. Calibration Fixture For Anemometer Probes

    NASA Technical Reports Server (NTRS)

    Lewis, Charles R.; Nagel, Robert T.

    1993-01-01

    Fixture facilitates calibration of three-dimensional sideflow thermal anemometer probes. With fixture, probe oriented at number of angles throughout its design range. Readings calibrated as function of orientation in airflow. Calibration repeatable and verifiable.

  2. Landing Gear Components Noise Study - PIV and Hot-Wire Measurements

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Burley, Casey L.; Stead, Daniel J.; Becker, Lawrence E.; Price, Jennifer L.

    2010-01-01

    PIV and hot-wire measurements of the wake flow from rods and bars are presented. The test models include rods of different diameters and cross sections and a rod juxtaposed to a plate. The latter is representative of the latch door that is attached to an aircraft landing gear when the gear is deployed, while the single and multiple rod configurations tested are representative of some of the various struts and cables configuration present on an aircraft landing gear. The test set up is described and the flow measurements are presented. The effect of model surface treatment and freestream turbulence on the spanwise coherence of the vortex shedding is studied for several rod and bar configurations.

  3. Computational aspects of hot-wire identification of thermal conductivity and diffusivity under high temperature

    NASA Astrophysics Data System (ADS)

    Vala, Jiří; Jarošová, Petra

    2016-07-01

    Development of advanced materials resistant to high temperature, needed namely for the design of heat storage for low-energy and passive buildings, requires simple, inexpensive and reliable methods of identification of their temperature-sensitive thermal conductivity and diffusivity, covering both well-advised experimental setting and implementation of robust and effective computational algorithms. Special geometrical configurations offer a possibility of quasi-analytical evaluation of temperature development for direct problems, whereas inverse problems of simultaneous evaluation of thermal conductivity and diffusivity must be handled carefully, using some least-squares (minimum variance) arguments. This paper demonstrates the proper mathematical and computational approach to such model problem, thanks to the radial symmetry of hot-wire measurements, including its numerical implementation.

  4. A hot-wire method based thermal conductivity measurement apparatus for teaching purposes

    NASA Astrophysics Data System (ADS)

    Alvarado, S.; Marín, E.; Juárez, A. G.; Calderón, A.; Ivanov, R.

    2012-07-01

    The implementation of an automated system based on the hot-wire technique is described for the measurement of the thermal conductivity of liquids using equipment easily available in modern physics laboratories at high schools and universities (basically a precision current source and a voltage meter, a data acquisition card, a personal computer and a high purity platinum wire). The wire, which is immersed in the investigated sample, is heated by passing a constant electrical current through it, and its temperature evolution, ΔT, is measured as a function of time, t, for several values of the current. A straightforward methodology is then used for data processing in order to obtain the liquid thermal conductivity. The start point is the well known linear relationship between ΔT and ln(t) predicted for long heating times by a model based on a solution of the heat conduction equation for an infinite lineal heat source embedded in an infinite medium into which heat is conducted without convective and radiative heat losses. A criterion is used to verify that the selected linear region is the one that matches the conditions imposed by the theoretical model. As a consequence the method involves least-squares fits in linear, semi-logarithmic (semi-log) and log-log graphs, so that it becomes attractive not only to teach about heat transfer and thermal properties measurement techniques, but also as a good exercise for students of undergraduate courses of physics and engineering learning about these kinds of mathematical functional relationships between variables. The functionality of the experiment was demonstrated by measuring the thermal conductivity in samples of liquids with well known thermal properties.

  5. Distributed image processing system for the monitoring of hot steel wire

    NASA Astrophysics Data System (ADS)

    O'Leary, Paul; Weiss, Michael; Schiller, Arnulf

    2003-05-01

    In a prototype for monitoring hot steel wire different technologies are integrated to achieve a robust, flexibly configurable and scalable imaging system. It is designed as a distributed system with private network and Tuplespace communication implementable on a LINUX Server. Intelligent cameras grab and process the image data. For real time communication between the cameras and standard industrial I/O-modules (IEC-61131) MODBUS/TCP messaging is applied. A switch with integrated firewall makes services available to the supervisory control system. Results are available as XML-logfiles. The image processing defines the upper and lower edges of the material by minimum/maximum filtering of the y-gradient. Dual Grassmanian coordinates are used to fit two parallel lines to the edge points by singular value decomposition. This gives the distance between the lines and the confidence interval of each measurement simultaneously, whereas latter is used to reject poor data. Changes of the distance are analysed computing local central moments. Presently, 12 images per second are acquired. The application is able to detect spontaneous rotation of the wire around the axis of rolling directly at the rolling stands and treats also poor images (due to steam of cooling water). It indicates resulting defects, which may go undetected otherwise.

  6. Epitaxial Thin Film Silicon Solar Cells Fabricated by Hot Wire Chemical Vapor Deposition Below 750 ..deg..C: Preprint

    SciTech Connect

    Alberi, K.; Martin, I. T.; Shub, M.; Teplin, C. W.; Iwaniczko, E.; Xu, Y.; duda, A.; Stradin, P.; Johnston, S. W.; Romero, M. J.; Branz, H. M.; Young, D. L.

    2009-06-01

    We report on fabricating film c-Si solar cells on Si wafer templates by hot-wire chemical vapor deposition. These devices, grown at glass-compatible temperatures < 750..deg..C, demonstrate open-circuit voltages > 500 mV and efficiencies > 5%.

  7. On the possibility to grow zinc oxide-based transparent conducting oxide films by hot-wire chemical vapor deposition

    SciTech Connect

    Abrutis, Adulfas Silimavicus, Laimis; Kubilius, Virgaudas; Murauskas, Tomas; Saltyte, Zita; Kuprenaite, Sabina; Plausinaitiene, Valentina

    2014-03-15

    Hot-wire chemical vapor deposition (HW-CVD) was applied to grow zinc oxide (ZnO)-based transparent conducting oxide (TCO) films. Indium (In)-doped ZnO films were deposited using a cold wall pulsed liquid injection CVD system with three nichrome wires installed at a distance of 2 cm from the substrate holder. The wires were heated by an AC current in the range of 0–10 A. Zn and In 2,2,6,6-tetramethyl-3,5-heptanedionates dissolved in 1,2-dimethoxyethane were used as precursors. The hot wires had a marked effect on the growth rates of ZnO, In-doped ZnO, and In{sub 2}O{sub 3} films; at a current of 6–10 A, growth rates were increased by a factor of ≈10–20 compared with those of traditional CVD at the same substrate temperature (400 °C). In-doped ZnO films with thickness of ≈150 nm deposited on sapphire-R grown at a wire current of 9 A exhibited a resistivity of ≈2 × 10{sup −3} Ωcm and transparency of >90% in the visible spectral range. These initial results reveal the potential of HW-CVD for the growth of TCOs.

  8. Necessary Conditions for Accurate, Transient Hot-Wire Measurements of the Apparent Thermal Conductivity of Nanofluids are Seldom Satisfied

    NASA Astrophysics Data System (ADS)

    Antoniadis, Konstantinos D.; Tertsinidou, Georgia J.; Assael, Marc J.; Wakeham, William A.

    2016-08-01

    The paper considers the conditions that are necessary to secure accurate measurement of the apparent thermal conductivity of two-phase systems comprising nanoscale particles of one material suspended in a fluid phase of a different material. It is shown that instruments operating according to the transient hot-wire technique can, indeed, produce excellent measurements when a finite element method (FEM) is employed to describe the instrument for the exact geometry of the hot wire. Furthermore, it is shown that an approximate analytic solution can be employed with equal success, over the time range of 0.1 s to 1 s, provided that (a) two wires are employed, so that end effects are canceled, (b) each wire is very thin, less than 30 \\upmu m diameter, so that the line source model and the corresponding corrections are valid, (c) low values of the temperature rise, less than 4 K, are employed in order to minimize the effect of convection on the heat transfer in the time of measurement of 1 s, and (d) insulated wires are employed for measurements in electrically conducting or polar liquids to avoid current leakage or other electrical distortions. According to these criteria, a transient hot-wire instrument has been designed, constructed, and employed for the measurement of the enhancement of the thermal conductivity of water when TiO2 or multi-wall carbon nanotubes (MWCNT) are added. These new results, together with a critical evaluation of other measurements, demonstrate the importance of proper implementation of the technique.

  9. On Cup Anemometer Rotor Aerodynamics

    PubMed Central

    Pindado, Santiago; Pérez, Javier; Avila-Sanchez, Sergio

    2012-01-01

    The influence of anemometer rotor shape parameters, such as the cups' front area or their center rotation radius on the anemometer's performance was analyzed. This analysis was based on calibrations performed on two different anemometers (one based on magnet system output signal, and the other one based on an opto-electronic system output signal), tested with 21 different rotors. The results were compared to the ones resulting from classical analytical models. The results clearly showed a linear dependency of both calibration constants, the slope and the offset, on the cups' center rotation radius, the influence of the front area of the cups also being observed. The analytical model of Kondo et al. was proved to be accurate if it is based on precise data related to the aerodynamic behavior of a rotor's cup. PMID:22778638

  10. On cup anemometer rotor aerodynamics.

    PubMed

    Pindado, Santiago; Pérez, Javier; Avila-Sanchez, Sergio

    2012-01-01

    The influence of anemometer rotor shape parameters, such as the cups' front area or their center rotation radius on the anemometer's performance was analyzed. This analysis was based on calibrations performed on two different anemometers (one based on magnet system output signal, and the other one based on an opto-electronic system output signal), tested with 21 different rotors. The results were compared to the ones resulting from classical analytical models. The results clearly showed a linear dependency of both calibration constants, the slope and the offset, on the cups' center rotation radius, the influence of the front area of the cups also being observed. The analytical model of Kondo et al. was proved to be accurate if it is based on precise data related to the aerodynamic behavior of a rotor's cup.

  11. Hot wire needle probe for in-reactor thermal conductivity measurement

    SciTech Connect

    JE Daw; JL Rempe; DL Knudson

    2012-08-01

    Thermal conductivity is a key property that must be known for proper design, test, and application of new fuels and structural materials in nuclear reactors. Thermal conductivity is highly dependent on the physical structure, chemical composition, and the state of the material. Typically, thermal conductivity changes that occur during irradiation are measured out-of-pile by Post Irradiated Examination (PIE) using a “cook and look” approach in hot-cells. Repeatedly removing samples from a test reactor to make out-of-pile measurements is expensive, has the potential to disturb phenomena of interest, and only provides understanding of the sample's end state at the time each measurement is made. There are also limited thermophysical property data for advanced fuels. Such data are needed for simulation design codes, the development of next generation reactors, and advanced fuels for existing nuclear plants. Being able to quickly characterize fuel thermal conductivity during irradiation can improve the fidelity of data, reduce costs of post-irradiation examinations, increase understanding of how fuels behave under irradiation, and confirm or improve existing thermal conductivity measurement techniques. This paper discusses recent efforts to develop and evaluate an in-pile thermal conductivity sensor based on a hot wire needle probe. Testing has been performed on samples with thermal conductivities ranging from 0.2 W/m-K to 22 W-m-K in temperatures ranging from 20 °C to 600 °C. Thermal conductivity values measured using the needle probe match data found in the literature to within 5% for samples tested at room temperature, 5.67% for low thermal conductivity samples tested at high temperatures, and 10% for high thermal conductivity samples tested at high temperatures. Experimental results also show that this sensor is capable of operating in various test conditions and of surviving long duration irradiations.

  12. Hot-Wire Deposition Study of Amorphous and Microcrystalline Silicon Using Different Temperature and Gas Flow

    NASA Astrophysics Data System (ADS)

    Povolny, Henry; Deng, Xunming

    2002-03-01

    μc-Si:H and α-Si:H films were deposited using a novel Hot Wire Chemical Vapor Deposition system that employs a coiled filament and three separate process gas inlets. A series of films were deposited at filament temperatures Tf ranging from 1500 to 2100 °C and substrate temperatures Ts from 150 to 300 °C. Raman, UV-Visible and IR transmission measurement were taken on these samples. Results show films deposited at low Ts and high Tf tend to be microcrystalline while films deposited at high Ts and low Tf tend to be amorphous. A second series of films were deposited using different gas flow geometries. Films were microcrystalline when Si_2H6 and H2 were directed into the chamber via separate inlets: one through the coiled filament and the other through a gas ring next to the substrate. When both gases were directed into the chamber via the same gas inlet, amorphous films were obtained. * Work was supported by NREL under Thin Film Partnership Program ZAF-8-17619-14 and NDJ-2-30630-08.

  13. Crystal Silicon Heterojunction Solar Cells by Hot-Wire CVD: Preprint

    SciTech Connect

    Wang, Q.; Page, M. R.; Iwaniczko, E.; Xu, Y. Q.; Roybal, L.; Bauer, R.; To, B.; Yuan, H. C.; Duda, A.; Yan, Y. F.

    2008-05-01

    Hot-wire chemical vapor deposition (HWCVD) is a promising technique for fabricating Silicon heterojunction (SHJ) solar cells. In this paper we describe our efforts to increase the open circuit voltage (Voc) while improving the efficiency of these devices. On p-type c-Si float-zone wafers, we used a double heterojunction structure with an amorphous n/i contact to the top surface and an i/p contact to the back surface to obtain an open circuit voltage (Voc) of 679 mV in a 0.9 cm2 cell with an independently confirmed efficiency of 19.1%. This is the best reported performance for a cell of this configuration. We also made progress on p-type CZ wafers and achieved 18.7% independently confirmed efficiency with little degradation under prolong illumination. Our best Voc for a p-type SHJ cell is 0.688 V, which is close to the 691 mV we achieved for SHJ cells on n type c-Si wafers.

  14. Anomalously high thermal conductivity of amorphous Si deposited by hot-wire chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Yang, Ho-Soon; Cahill, David G.; Liu, X.; Feldman, J. L.; Crandall, R. S.; Sperling, B. A.; Abelson, J. R.

    2010-03-01

    The thermal conductivities of thin films of amorphous Si (a-Si) deposited by hot-wire chemical vapor deposition (HWCVD) are measured by time-domain thermoreflectance (TDTR). Amorphous Si samples prepared at the National Renewable Energy Laboratory (NREL) show an anomalous enhancement in thermal conductivity compared to other forms of a-Si and compared to the prediction of the model of the minimum thermal conductivity. The thermal conductivity of the NREL HWCVD a-Si samples also decreases with increasing frequency of the temperature fields used in the experiment. This frequency dependence of the thermal conductivity is nearly identical to the results of our previous studies of crystalline semiconductor alloys; a comparison of the frequency dependence to a phonon-scattering model suggests that Rayleigh-type scattering controls the mean-free path of ˜5meV phonons in this material. Amorphous Si films prepared at University of Illinois (U. Illinois) do not show an enhanced thermal conductivity even though Raman vibrational spectra of the U. Illinois and NREL samples are nearly identical. Thus, the thermal conductivity of a-Si depends on details of the microstructure that are not revealed by vibrational spectroscopy and measurements by TDTR provide a convenient method of identifying novel microstructures in amorphous materials.

  15. Response of the Nevzorov hot wire probe in Arctic clouds dominated by very large droplet sizes

    NASA Astrophysics Data System (ADS)

    Schwarzenboeck, A.; Mioche, G.; Armetta, A.; Herber, A.; Gayet, J.-F.

    2009-05-01

    During the airborne research mission ASTAR 2004 (Arctic Study of Tropospheric Aerosols, Clouds and Radiation) performed over the island of Svalbard in the Arctic a constant-temperature hot-wire Nevzorov Probe designed for aircraft measurements, has been used onboard the aircraft POLAR 2. The Nevzorov probe measured liquid water (LWC) and total condensed water content (TWC) in supercooled liquid and partly mixed phase clouds, respectively. As for other hotwire probes the calculation of LWC and/or TWC (and thus the ice water content IWC) has to take into account the collection efficiencies of the two separate sensors for LWC and TWC which both react differently with respect to cloud phase and what is even more difficult to quantify with respect to the size of ice and liquid cloud particles. The study demonstrates that during pure liquid cloud sequences the ASTAR data set of the Nevzorov probe allowed to improve the quantification of the collection efficiency, particularly of the LWC probe part with respect to water. The improved quantification of liquid water content should lead to improved retrievals of IWC content. Simultaneous retrievals of LWC and IWC are correlated with the asymmetry factor derived from the Polar Nephelometer instrument.

  16. Very thin and stable thin-film silicon alloy triple junction solar cells by hot wire chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Veldhuizen, L. W.; Schropp, R. E. I.

    2016-08-01

    We present a silicon-based triple junction solar cell that requires a deposition time of less than 15 min for all photoactive layers. As a low-bandgap material, we used thin layers of hydrogenated amorphous silicon germanium with lower band gap than commonly used, which is possible due to the application of hot wire chemical vapor deposition. The triple junction cell shows an initial energy conversion efficiency exceeding 10%, and with a relative performance stability within 6%, the cell shows a high tolerance to light-induced degradation. With these results, we help to demonstrate that hot wire chemical vapor deposition is a viable deposition method for the fabrication of low-cost solar cells.

  17. Fiber optic hot-wire flowmeter based on a metallic coated hybrid long period grating/fiber Bragg grating structure.

    PubMed

    Caldas, Paulo; Jorge, Pedro A S; Rego, Gaspar; Frazão, Orlando; Santos, José Luís; Ferreira, Luís Alberto; Araújo, Francisco

    2011-06-10

    In this work an all-optical hot-wire flowmeter based on a silver coated fiber combining a long period grating and a fiber Bragg grating (FBG) structure is proposed. Light from a pump laser at 1480  nm propagating down the fiber is coupled by the long period grating into the fiber cladding and is absorbed by the silver coating deposited on the fiber surface over the Bragg grating structure. This absorption acts like a hot wire raising the fiber temperature locally, which is effectively detected by the FBG resonance shift. The temperature increase depends on the flow speed of the surrounding air, which has the effect of cooling the fiber. It is demonstrated that the Bragg wavelength shift can be related to the flow speed. A flow speed resolution of 0.08  m/s is achieved using this new configuration. PMID:21673779

  18. Photodetectors on the basis of Ge/Si(001) heterostructures grown by the hot-wire CVD technique

    SciTech Connect

    Shengurov, V. G. Chalkov, V. Yu.; Denisov, S. A.; Alyabina, N. A.; Guseinov, D. V.; Trushin, V. N.; Gorshkov, A. P.; Volkova, N. S.; Ivanova, M. M.; Kruglov, A. V.; Filatov, D. O.

    2015-10-15

    The fabrication of photodetectors for the wavelength range of communications λ = 1.3–1.55 µm on the basis of Ge/Si(001) heterostructures with thick (∼0.5 µm) Ge layers grown by the hot-wire technique at reduced growth temperatures (350°C) is reported. The single-crystal Ga layers are distinguished by a low density of threading dislocations (∼10{sup 5} cm{sup –2}). The photodetectors exhibit a rather high quantum efficiency (∼0.05 at λ = 1.5 µm and 300 K) at moderate reverse saturation current densities (∼10{sup –2} A cm{sup –2}). Thus, it is shown that the hot-wire technique offers promise for the formation of integrated photodetectors for the wavelength range of communications, especially in the case of limitations on the conditions of heat treatments.

  19. Wind Speed Measurement by Paper Anemometer

    ERIC Educational Resources Information Center

    Zhong, Juhua; Cheng, Zhongqi; Guan, Wenchuan

    2011-01-01

    A simple wind speed measurement device, a paper anemometer, is fabricated based on the theory of standing waves. In providing the working profile of the paper anemometer, an experimental device is established, which consists of an anemometer sensor, a sound sensor, a microphone, paper strips, a paper cup, and sonic acquisition software. It shows…

  20. Airflow Measurement of the Car HVAC Unit Using Hot-wire Anemometry

    NASA Astrophysics Data System (ADS)

    Fojtlín, Miloš; Planka, Michal; Fišer, Jan; Pokorný, Jan; Jícha, Miroslav

    2016-03-01

    Thermal environment in a vehicular cabin significantly influence drivers' fatigue and passengers' thermal comfort. This environment is traditionally managed by HVAC cabin system that distributes air and modifies its properties. In order to simulate cabin thermal behaviour, amount of the air led through car vents must be determined. The aim of this study was to develop methodology to measure airflow from the vents, and consequently calculate corresponding air distribution coefficients. Three climatic cases were selected to match European winter, summer, and spring / fall conditions. Experiments were conducted on a test vehicle in a climatic chamber. The car HVAC system was set to automatic control mode, and the measurements were executed after the system stabilisation—each case was independently measured three times. To be able to evaluate precision of the method, the airflow was determined at the system inlet (HVAC suction) and outlet (each vent), and the total airflow values were compared. The airflow was calculated by determining a mean value of the air velocity multiplied by an area of inlet / outlet cross-section. Hot-wire anemometry was involved to measure the air velocity. Regarding the summer case, total airflow entering the cabin was around 57 l s-1 with 60 % of the air entering the cabin through dashboard vents; no air was supplied to the feet compartment. The remaining cases had the same total airflow of around 42 l s-1, and the air distribution was focused mainly on feet and windows. The inlet and outlet airflow values show a good match with a maximum mass differential of 8.3 %.

  1. Comparison of anemometers for turbulence characterization

    SciTech Connect

    Morris, V.R.; Barnard, J.C.; Wendell, L.L.; Tomich, S.D.

    1992-10-01

    During the first phase of the US Department of Energy's turbulence characterization program, important discoveries were made about the field application of propeller-vane and cup anemometers under very turbulent conditions. First, averaged speeds measured by the propeller-vane anemometer were consistently lower than those from the cup anemometer, even though both registered virtually the same during wind-tunnel calibration testing. Second, the propeller-vane anemometers suffered from structural failures much more frequently than the cup anemometers. The difficulties associated with the use of the propeller-vane motivated us to consider the cup anemometer for turbulence measurements. At fast sample rates, the output of the cup anemometer is severely degraded by discretization error that stems from pulse counting demodulation. However, we found that a low-pass Gaussian filter could be applied to the time series of wind speed derived from the cup anemometer to yield time series and frequency spectra that compared very favorably with those obtained from the propeller-vane anemometer. This finding suggests that the cup anemometer may prove to be an inexpensive and rugged sensor appropriate for turbulence measurements for wind-energy applications.

  2. Hot-wire chemical vapour deposition at low substrate temperatures for optoelectronic applications

    NASA Astrophysics Data System (ADS)

    Bakker, R.

    2010-09-01

    The need for large quantities of rapidly and cheaply produced electronic devices has increased rapidly over the past decades. The transistors and diodes that are used to build these devices are predominantly made of crystalline silicon. Since crystalline silicon is very expensive to produce on a large scale and cannot be directly deposited on plastic substrates, much research is being done on thin film amorphous or nanocrystalline semiconductors and insulators. Hot-wire chemical vapour deposition (HWCVD) is a novel, low cost, and convenient way to deposit these materials. The process can be controlled in such a way that specific chemical reactions take place and unwanted side reactions are minimized. It can easily be scaled up to produce large-area thin film electronics. Conventionally, plasma enhanced chemical vapour deposition (PECVD) is used to deposit semiconductors and inorganic dielectrics. Recently, HWCVD has been explored for fast deposition of such materials. An adaptation of HWCVD, initiated chemical vapour deposition (iCVD), offers the unique possibility of producing organic materials and polymers in a vacuum reactor, without the use of solvents. This technique was originally proposed at the Massachusetts institute of technology (MIT) by Prof. Karen Gleason. The iCVD process involves the creation of radicals by dissociation of a peroxide (a molecule with a ~O-O~ bond) by a heated wire in a vacuum reactor. This radical initiates a polymerization reaction of a vinyl (a molecule with a double carbon-carbon bond, ~C=C~) monomer at a substrate held at room temperature. This thesis describes a dedicated iCVD reactor for polymer deposition, installed at Utrecht University, along with a reactor with a cooled substrate holder in an existing HWCVD multi-chamber setup for low-temperature silicon nitride (SiNx) depositions. The most important features of these reactors are described and the characterization techniques are explained. This thesis contains four new

  3. Comparison of hot-wire measurement techniques in a Mach 3 pilot quiet tunnel

    NASA Technical Reports Server (NTRS)

    Chen, F.-J.; Beckwith, I. E.

    1985-01-01

    Disturbance measurements were made in the free stream of a small Mach 3 quiet tunnel using constant-current and constant-temperature anemometers (CCA and CTA). Data from the two types of instruments are compared in terms of frequency response and normalized rms levels of mass flow fluctuations. The mode-diagram analysis of the CCA data produces reliable results because the frequency response is consistent for a wide range of overheat ratios. However, the mode-diagram results for the CTA data cannot be used due to the rapidly decreasing frequency response with decreasing overheat ratio. Only the mass flow fluctuations at high overheat ratio can be obtained with the CTA system, and they can be as much as 50 percent higher than those from the CCA system. Possible reasons for these measurement differences between the two systems are considered.

  4. FireWire: Hot New Multimedia Interface or Flash in the Pan?

    ERIC Educational Resources Information Center

    Learn, Larry L., Ed.

    1995-01-01

    Examines potential solutions to the problem of personal computer cabling and configuration and serial port performance, namely "FireWire" (P1394) and "Universal Serial Bus" (USB). Discusses interface design, technical capabilities, user friendliness, compatibility, costs, and future perspectives. (AEF)

  5. Method and apparatus for fabricating a thin-film solar cell utilizing a hot wire chemical vapor deposition technique

    DOEpatents

    Wang, Qi; Iwaniczko, Eugene

    2006-10-17

    A thin-film solar cell is provided. The thin-film solar cell comprises an a-SiGe:H (1.6 eV) n-i-p solar cell having a deposition rate of at least ten (10) .ANG./second for the a-SiGe:H intrinsic layer by hot wire chemical vapor deposition. A method for fabricating a thin film solar cell is also provided. The method comprises depositing a n-i-p layer at a deposition rate of at least ten (10) .ANG./second for the a-SiGe:H intrinsic layer.

  6. Sliding bubbles on a hot horizontal wire in a subcooled bath

    NASA Astrophysics Data System (ADS)

    Duchesne, Alexis; Dubois, Charles; Caps, Hervé

    2015-11-01

    When a wire is heated up to the boiling point in a liquid bath some bubbles will nucleate on the wire surface. Traditional nucleate boiling theory predicts that bubbles generate from active nucleate site, grow up and depart from the heating surface due to buoyancy and inertia. However, an alternative scenario is presented in the literature for a subcooled bath: bubbles slide along the horizontal wire before departing. New experiments were performed by using a constantan wire and different liquids, varying the injected power. Silicone oil, water and even liquid nitrogen were tested in order to vary wetting conditions, liquid viscosities and surface tensions. We explored the influence of the wire diameter and of the subcooled bath temperature. We observed, of course, sliding motion, but also a wide range of behaviors from bubbles clustering to film boiling. We noticed that bubbles could change moving sense, especially when encountering with another bubble. The bubble speed is carefully measured and can reach more than 100 mm/s for a millimetric bubble. We investigated the dependence of the speed on the different parameters and found that this speed is, for a given configuration, quite independent of the injected power. We understand these phenomena in terms of Marangoni effects. This project has been financially supported by ARC SuperCool contract of the University of Liège.

  7. A Novel Portable Absolute Transient Hot-Wire Instrument for the Measurement of the Thermal Conductivity of Solids

    NASA Astrophysics Data System (ADS)

    Assael, Marc J.; Antoniadis, Konstantinos D.; Metaxa, Ifigeneia N.; Mylona, Sofia K.; Assael, John-Alexander M.; Wu, Jiangtao; Hu, Miaomiao

    2015-11-01

    A new portable absolute Transient Hot-Wire instrument for measuring the thermal conductivity of solids over a range of 0.2 { W}{\\cdot }m^{-1}{\\cdot }{K}^{-1} to 4 { W}{\\cdot }m^{-1}{\\cdot }{K}^{-1} is presented. The new instrument is characterized by three novelties: (a) an innovative two-wires sensor which provides robustness and portability, while at the same time employs a soft silicone layer to eliminate the effect of the contact resistance between the wires and the sample, (b) a newly designed compact portable printed electronic board employing an FPGA architecture CPU to the control output voltage and data processing—the new board replaces the traditional, large in size Wheatstone-type bridge system required to perform the experimental measurements, and (c) a cutting-edge software suite, developed for the mesh describing the structure of the sensor, and utilizing the Finite Elements Method to model the heat flow. The estimation of thermal conductivity is modeled as a minimization problem and is solved using Bayesian Optimization. Our revolutionizing proposed methodology exhibits radical speedups of up to × 120, compared to previous approaches, and considerably reduces the number of simulations performed, achieving convergence only in a few minutes. The new instrument was successfully employed to measure, at room temperature, the thermal conductivity of two thermal conductivity reference materials, Pyroceram 9606 and Pyrex 7740, and two possible candidate glassy solids, PMMA and BK7, with an absolute low uncertainty of 2 %.

  8. Microstructure and mechanical properties of hot wire laser clad layers for repairing precipitation hardening martensitic stainless steel

    NASA Astrophysics Data System (ADS)

    Wen, Peng; Cai, Zhipeng; Feng, Zhenhua; Wang, Gang

    2015-12-01

    Precipitation hardening martensitic stainless steel (PH-MSS) is widely used as load-bearing parts because of its excellent overall properties. It is economical and flexible to repair the failure parts instead of changing new ones. However, it is difficult to keep properties of repaired part as good as those of the substrate. With preheating wire by resistance heat, hot wire laser cladding owns both merits of low heat input and high deposition efficiency, thus is regarded as an advantaged repairing technology for damaged parts of high value. Multi-pass layers were cladded on the surface of FV520B by hot wire laser cladding. The microstructure and mechanical properties were compared and analyzed for the substrate and the clad layer. For the as-cladded layer, microstructure was found non-uniform and divided into quenched and tempered regions. Tensile strength was almost equivalent to that of the substrate, while ductility and impact toughness deteriorated much. With using laser scanning layer by layer during laser cladding, microstructure of the clad layers was tempered to fine martensite uniformly. The ductility and toughness of the clad layer were improved to be equivalent to those of the substrate, while the tensile strength was a little lower than that of the substrate. By adding TiC nanoparticles as well as laser scanning, the precipitation strengthening effect was improved and the structure was refined in the clad layer. The strength, ductility and toughness were all improved further. Finally, high quality clad layers were obtained with equivalent or even superior mechanical properties to the substrate, offering a valuable technique to repair PH-MSS.

  9. Transverse vorticity measurements using an array of four hot-wire probes

    NASA Technical Reports Server (NTRS)

    Foss, J. F.; Klewickc, C. L.; Disimile, P. J.

    1986-01-01

    A comprehensive description of the technique used to obtain a time series of the quasi-instantaneous transverse vorticity from a four wire array of probes is presented. The algorithmic structure which supports the technique is described in detail and demonstration data, from a large plane shear layer, are presented to provide a specific utilization of the technique. Sensitivity calculations are provided which allow one contribution to the inherent uncertainty of the technique to be evaluated.

  10. Laser transit anemometer experiences in supersonic flow

    NASA Technical Reports Server (NTRS)

    Hunter, William W., Jr.; Humphreys, William M., Jr.

    1988-01-01

    The purpose of this paper is to present examples of velocity measurements obtained in supersonic flow fields with the laser transit anemometer system. Velocity measurements of a supersonic jet exhausting in a transonic flow field, a cone boundary survey in a Mach 4 flow field, and a determination of the periodic disturbance frequencies of a sonic nozzle flow field are presented. Each of the above three cases also serves to illustrate different modes of laser transit anemometer operation. A brief description of the laser transit anemometer system is also presented.

  11. Laser Anemometer Measurements of the Three-Dimensional Rotor Flow Field in the NASA Low-Speed Centrifugal Compressor

    NASA Technical Reports Server (NTRS)

    Hathaway, Michael D.; Chriss, Randall M.; Strazisar, Anthony J.; Wood, Jerry R.

    1995-01-01

    A laser anemometer system was used to provide detailed surveys of the three-dimensional velocity field within the NASA low-speed centrifugal impeller operating with a vaneless diffuser. Both laser anemometer and aerodynamic performance data were acquired at the design flow rate and at a lower flow rate. Floor path coordinates, detailed blade geometry, and pneumatic probe survey results are presented in tabular form. The laser anemometer data are presented in the form of pitchwise distributions of axial, radial, and relative tangential velocity on blade-to-blade stream surfaces at 5-percent-of-span increments, starting at 95-percent-of-span from the hub. The laser anemometer data are also presented as contour and wire-frame plots of throughflow velocity and vector plots of secondary velocities at all measurement stations through the impeller.

  12. Characteristics of a micro-mechanical thermal flow sensor based on a two hot wires principle with constant temperature operation in a small channel

    NASA Astrophysics Data System (ADS)

    Lange, P.; Weiss, M.; Warnat, S.

    2014-12-01

    A thermal mass flow sensor with high dynamic flow range in silicon bulk micromachining membrane technology is presented. The response behavior of this sensor based on a two hot wire principle is described. This sensor configuration uses two hot wires mounted closely spaced one behind the other within a thin membrane, kept at the same temperature. The power to compensate cooling of and the interaction between the two hot wires are used to calculate mass flows and directionality of flows of gaseous and liquid fluids in a small channel. The response shows both anemometric and calorimetric behavior, depending on fluid, channel height and flow range. The hot wires are heated relative to temperature sensors located also on an isolated membrane on the same chip. Choosing an appropriate evaluation procedure an independence of the signal from the ambient temperature is achieved. This configuration will be discussed in view of the published results of single heater flow sensors, being of calorimetric or anemometric type. A calculation method for the determination of linear and power law range of the response is given.

  13. Hot-wire detector for chemically active materials used in gas chromatography

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Hot-filament detector analyzes chemically active materials used in gas chromatography. The detector reacts chemically with the effluent vapors in the gas chromatographic apparatus to change the electrical resistance of the filament as a function of the affluent composition. Due to the changes produced by chemical action on the filament, the system is often calibrated.

  14. Tethersonde and kite anemometer evaluation

    SciTech Connect

    Chow, W.Y.; Kirchhoff, R.H.

    1988-10-01

    The responses of kite anemometers and tethersonde balloons to the dynamics of the wind are investigated in this study. A three-phase effort of theoretical development, experimental measurement, and comparison of data and theory was undertaken to provide further understanding of how a kite or balloon responds to atmospheric turbulence. Understanding the effect on wind velocity measurements obtained using these instruments is important to their use in, for example, identifying optimum wind turbine sites. The theoretical development included: (1) an extension of double theodolite theory, to provide a mechanism for calculating instrument displacement, and (2) linear small perturbation analysis of the effect of atmospheric turbulence on kite or balloon motion. The results of the small perturbation analyses were response equations that analyze the movement of the kite or balloon as a function of the mean elevation angle of the kite or balloon and turbulence parameters of the wind. The response equations provide the ratio of the fluctuating string tension to the mean string tension (for the kite) and the fluctuating elevation angle for the kite and balloon. 18 refs., 66 figs., 22 tabs.

  15. A rotating hot-wire technique for spatial sampling of disturbed and manipulated duct flows

    NASA Technical Reports Server (NTRS)

    Wark, C. E.; Nagib, H. M.; Jennings, M. J.

    1990-01-01

    A duct flow spatial sampling technique, in which an X-wire probe is rotated about the center of a cylindrical test section at a radius equal to one-half that of the test section in order to furnish nearly instantaneous multipoint measurements of the streamwise and azimuthal components, is presently evaluated in view of the control of flow disturbances downstream of various open inlet contractions. The effectiveness of a particular contraction in controlling ingested flow disturbances was ascertained by artificially introducing disturbances upstream of the contractions; control effectiveness if found to be strongly dependent on inlet contraction, with consequences for the reduction of passing-blade frequency noise during gas turbine engine ground testing.

  16. Cyclic hot firing results of tungsten-wire-reinforced, copper-lined thrust chambers

    NASA Technical Reports Server (NTRS)

    Kazaroff, John M.; Jankovsky, Robert S.

    1990-01-01

    An advanced thrust liner material for potential long life reusable rocket engines is described. This liner material was produced with the intent of improving the reusable life of high pressure thrust chambers by strengthening the chamber in the hoop direction, thus avoiding the longitudinal cracking due to low cycle fatigue that is observed in conventional homogeneous copper chambers, but yet not reducing the high thermal conductivity that is essential when operating with high heat fluxes. The liner material produced was a tungsten wire reinforced copper composite. Incorporating this composite into two hydrogen-oxygen test rocket chambers was done so that its performance as a reusable liner material could be evaluated. Testing results showed that both chambers failed prematurely, but the crack sites were perpendicular to the normal direction of cracking indicating a degree of success in containing the tremendous thermal strain associated with high temperature rocket engines. The failures, in all cases, were associated with drilled instrumentation ports and no other damages or deformations were found elsewhere in the composite liners.

  17. High-angle tilt boundary graphene domain recrystallized from mobile hot-wire-assisted chemical vapor deposition system.

    PubMed

    Lee, Jinsup; Baek, Jinwook; Ryu, Gyeong Hee; Lee, Mi Jin; Oh, Seran; Hong, Seul Ki; Kim, Bo-Hyun; Lee, Seok-Hee; Cho, Byung Jin; Lee, Zonghoon; Jeon, Seokwoo

    2014-08-13

    Crystallization of materials has attracted research interest for a long time, and its mechanisms in three-dimensional materials have been well studied. However, crystallization of two-dimensional (2D) materials is yet to be challenged. Clarifying the dynamics underlying growth of 2D materials will provide the insight for the potential route to synthesize large and highly crystallized 2D domains with low defects. Here, we present the growth dynamics and recrystallization of 2D material graphene under a mobile hot-wire assisted chemical vapor deposition (MHW-CVD) system. Under local but sequential heating by MHW-CVD system, the initial nucleation of nanocrystalline graphenes, which was not extended into the growth stage due to the insufficient thermal energy, took a recrystallization and converted into a grand single crystal domain. During this process, the stitching-like healing of graphene was also observed. The local but sequential endowing thermal energy to nanocrystalline graphenes enabled us to simultaneously reveal the recrystallization and healing dynamics in graphene growth, which suggests an alternative route to synthesize a highly crystalline and large domain size graphene. Also, this recrystallization and healing of 2D nanocrystalline graphenes offers an interesting insight on the growth mechanism of 2D materials.

  18. Thin film solar cells with Si nanocrystallites embedded in amorphous intrinsic layers by hot-wire chemical vapor deposition.

    PubMed

    Park, Seungil; Parida, Bhaskar; Kim, Keunjoo

    2013-05-01

    We investigated the thin film growths of hydrogenated silicon by hot-wire chemical vapor deposition with different flow rates of SiH4 and H2 mixture ambient and fabricated thin film solar cells by implementing the intrinsic layers to SiC/Si heterojunction p-i-n structures. The film samples showed the different infrared absorption spectra of 2,000 and 2,100 cm(-1), which are corresponding to the chemical bonds of SiH and SiH2, respectively. The a-Si:H sample with the relatively high silane concentration provides the absorption peak of SiH bond, but the microc-Si:H sample with the relatively low silane concentration provides the absorption peak of SiH2 bond as well as SiH bond. Furthermore, the microc-Si:H sample showed the Raman spectral shift of 520 cm(-1) for crystalline phase Si bonds as well as the 480 cm(-1) for the amorphous phase Si bonds. These bonding structures are very consistent with the further analysis of the long-wavelength photoconduction tail and the formation of nanocrystalline Si structures. The microc-Si:H thin film solar cell has the photovoltaic behavior of open circuit voltage similar to crystalline silicon thin film solar cell, indicating that microc-Si:H thin film with the mixed phase of amorphous and nanocrystalline structures show the carrier transportation through the channel of nanocrystallites.

  19. High-angle tilt boundary graphene domain recrystallized from mobile hot-wire-assisted chemical vapor deposition system.

    PubMed

    Lee, Jinsup; Baek, Jinwook; Ryu, Gyeong Hee; Lee, Mi Jin; Oh, Seran; Hong, Seul Ki; Kim, Bo-Hyun; Lee, Seok-Hee; Cho, Byung Jin; Lee, Zonghoon; Jeon, Seokwoo

    2014-08-13

    Crystallization of materials has attracted research interest for a long time, and its mechanisms in three-dimensional materials have been well studied. However, crystallization of two-dimensional (2D) materials is yet to be challenged. Clarifying the dynamics underlying growth of 2D materials will provide the insight for the potential route to synthesize large and highly crystallized 2D domains with low defects. Here, we present the growth dynamics and recrystallization of 2D material graphene under a mobile hot-wire assisted chemical vapor deposition (MHW-CVD) system. Under local but sequential heating by MHW-CVD system, the initial nucleation of nanocrystalline graphenes, which was not extended into the growth stage due to the insufficient thermal energy, took a recrystallization and converted into a grand single crystal domain. During this process, the stitching-like healing of graphene was also observed. The local but sequential endowing thermal energy to nanocrystalline graphenes enabled us to simultaneously reveal the recrystallization and healing dynamics in graphene growth, which suggests an alternative route to synthesize a highly crystalline and large domain size graphene. Also, this recrystallization and healing of 2D nanocrystalline graphenes offers an interesting insight on the growth mechanism of 2D materials. PMID:24978293

  20. Response of the Nevzorov hot wire probe in clouds dominated by droplet conditions in the drizzle size range

    NASA Astrophysics Data System (ADS)

    Schwarzenboeck, A.; Mioche, G.; Armetta, A.; Herber, A.; Gayet, J.-F.

    2009-12-01

    During the airborne research mission ASTAR 2004 (Arctic Study of Tropospheric Aerosols, Clouds and Radiation) performed over the island of Svalbard in the Arctic a constant-temperature hot-wire Nevzorov Probe designed for aircraft measurements, has been used onboard the aircraft POLAR 2. The Nevzorov probe measured liquid water (LWC) and total condensed water content (TWC) in supercooled liquid and partly mixed phase clouds, respectively. As for other hotwire probes the calculation of LWC and/or TWC (and thus the ice water content IWC) has to take into account the collection efficiencies of the two separate sensors for LWC and TWC which both react differently with respect to cloud phase and what is even more difficult to quantify with respect to the size of ice and liquid cloud particles. The study demonstrates that during pure liquid cloud sequences the ASTAR data set of the Nevzorov probe allowed to improve the quantification of the collection efficiency, particularly of the LWC probe part with respect to water. The improved quantification of liquid water content should lead to improved retrievals of IWC content. Simultaneous retrievals of LWC and IWC are correlated with the asymmetry factor derived from the Polar Nephelometer instrument.

  1. Fabrication and characterization of silicon based thermal neutron detector with hot wire chemical vapor deposited boron carbide converter

    NASA Astrophysics Data System (ADS)

    Chaudhari, Pradip; Singh, Arvind; Topkar, Anita; Dusane, Rajiv

    2015-04-01

    In order to utilize the well established silicon detector technology for neutron detection application, a silicon based thermal neutron detector was fabricated by integrating a thin boron carbide layer as a neutron converter with a silicon PIN detector. Hot wire chemical vapor deposition (HWCVD), which is a low cost, low temperature process for deposition of thin films with precise thickness was explored as a technique for direct deposition of a boron carbide layer over the metalized front surface of the detector chip. The presence of B-C bonding and 10B isotope in the boron carbide film were confirmed by Fourier transform infrared spectroscopy and secondary ion mass spectrometry respectively. The deposition of HWCVD boron carbide layer being a low temperature process was observed not to cause degradation of the PIN detector. The response of the detector with 0.2 μm and 0.5 μm thick boron carbide layer was examined in a nuclear reactor. The pulse height spectrum shows evidence of thermal neutron response with signature of (n, α) reaction. The results presented in this article indicate that HWCVD boron carbide deposition technique would be suitable for low cost industrial fabrication of PIN based single element or 1D/2D position sensitive thermal neutron detectors.

  2. Low temperature deposition of polycrystalline silicon thin films on a flexible polymer substrate by hot wire chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Lee, Sang-hoon; Jung, Jae-soo; Lee, Sung-soo; Lee, Sung-bo; Hwang, Nong-moon

    2016-11-01

    For the applications such as flexible displays and solar cells, the direct deposition of crystalline silicon films on a flexible polymer substrate has been a great issue. Here, we investigated the direct deposition of polycrystalline silicon films on a polyimide film at the substrate temperature of 200 °C. The low temperature deposition of crystalline silicon on a flexible substrate has been successfully made based on two ideas. One is that the Si-Cl-H system has a retrograde solubility of silicon in the gas phase near the substrate temperature. The other is the new concept of non-classical crystallization, where films grow by the building block of nanoparticles formed in the gas phase during hot-wire chemical vapor deposition (HWCVD). The total amount of precipitation of silicon nanoparticles decreased with increasing HCl concentration. By adding HCl, the amount and the size of silicon nanoparticles were reduced remarkably, which is related with the low temperature deposition of silicon films of highly crystalline fraction with a very thin amorphous incubation layer. The dark conductivity of the intrinsic film prepared at the flow rate ratio of RHCl=[HCl]/[SiH4]=3.61 was 1.84×10-6 Scm-1 at room temperature. The Hall mobility of the n-type silicon film prepared at RHCl=3.61 was 5.72 cm2 V-1s-1. These electrical properties of silicon films are high enough and could be used in flexible electric devices.

  3. Wide-Gap Thin Film Si n-i-p Solar Cells Deposited by Hot-Wire CVD: Preprint

    SciTech Connect

    Wang, Q.; Iwaniczko, E.; Yang, J.; Lord, K.; Guha, S.; Wang, K.; Han, D.

    2002-05-01

    High-voltage wide bandgap thin-film Si n-i-p solar cells have been made using the hot-wire chemical vapor deposition (HWCVD) technique. The best open-circuit voltage (Voc) has exceeded 0.94 V in solar cells using HWCVD in the entire n-i-p structure. A Voc of 0.97V has been achieved using HWCVD in the n and i layers and plasma-enhanced (PE) CVD for the p layer. The high voltages are attributed to the wide-gap i layer and an improved p/i interface. The wide-gap i layer is obtained by using low substrate temperatures and sufficient hydrogen dilution during the growth of the i layer to arrive at the amorphous-to-microcrystalline phase transition region. The optical band gap (E04) of the i layer is found to be 1.90 eV. These high-voltage cells also exhibit good fill factors exceeding 0.7 with short-circuit-current densities of 8 to 10 mA/cm2 on bare stainless steel substrates. We have also carried out photoluminescence (PL) spectroscopy studies and found a correlation between Voc and the PL peak energy position.

  4. EBSD analysis of tungsten-filament carburization during the hot-wire CVD of multi-walled carbon nanotubes.

    PubMed

    Oliphant, Clive J; Arendse, Christopher J; Camagu, Sigqibo T; Swart, Hendrik

    2014-02-01

    Filament condition during hot-wire chemical vapor deposition conditions of multi-walled carbon nanotubes is a major concern for a stable deposition process. We report on the novel application of electron backscatter diffraction to characterize the carburization of tungsten filaments. During the synthesis, the W-filaments transform to W2C and WC. W-carbide growth followed a parabolic behavior corresponding to the diffusion of C as the rate-determining step. The grain size of W, W2C, and WC increases with longer exposure time and increasing filament temperature. The grain size of the recrystallizing W-core and W2C phase grows from the perimeter inwardly and this phenomenon is enhanced at filament temperatures in excess of 1,400°C. Cracks appear at filament temperatures >1,600°C, accompanied by a reduction in the filament operational lifetime. The increase of the W2C and recrystallized W-core grain size from the perimeter inwardly is ascribed to a thermal gradient within the filament, which in turn influences the hardness measurements and crack formation. PMID:24423105

  5. Hot wire chemical vapor deposition chemistry in the gas phase and on the catalyst surface with organosilicon compounds.

    PubMed

    Shi, Yujun

    2015-02-17

    CONSPECTUS: Hot wire chemical vapor deposition (HWCVD), also referred to as catalytic CVD (Cat-CVD), has been used to produce Si-containing thin films, nanomaterials, and functional polymer coatings that have found wide applications in microelectronic and photovoltaic devices, in automobiles, and in biotechnology. The success of HWCVD is largely due to its various advantages, including high deposition rate, low substrate temperatures, lack of plasma-induced damage, and large-area uniformity. Film growth in HWCVD is induced by reactive species generated from primary decomposition on the metal wire or from secondary reactions in the gas phase. In order to achieve a rational and efficient optimization of the process, it is essential to identify the reactive species and to understand the chemical kinetics that govern the production of these precursor species for film growth. In this Account, we report recent progress in unraveling the complex gas-phase reaction chemistry in the HWCVD growth of silicon carbide thin films using organosilicon compounds as single-source precursors. We have demonstrated that laser ionization mass spectrometry is a powerful diagnostic tool for studying the gas-phase reaction chemistry when combined with the methods of isotope labeling and chemical trapping. The four methyl-substituted silane molecules, belonging to open-chain alkylsilanes, dissociatively adsorb on W and Ta filaments to produce methyl radical and H2 molecule. Under the typical deposition pressures, with increasing number of methyl substitution, the dominant chemistry occurring in the gas phase switches from silylene/silene reactions to free-radical short chain reactions. This change in dominant reaction intermediates from silylene/silene to methyl radicals explains the observation from thin film deposition that silicon carbide films become more C-rich with a decreasing number of Si-H bonds in the four precursor molecules. In the case of cyclic monosilacyclobutanes, we have

  6. Measurement of the thermal conductivity of KNO3-NaNO3 mixtures using a transient hot-wire method with a liquid metal in a capillary probe

    NASA Astrophysics Data System (ADS)

    Omotani, T.; Nagasaka, Y.; Nagashima, A.

    1982-03-01

    The thermal conductivity of KNO3-NaNO3 mixtures was measured by a modified transient hot-wire method using liquid metal in a capillary as a heat source. The method was developed for measurements on electrically conducting liquids at high temperatures. Measurements were performed on pure NaNO3 and its three mixtures with KNO3 in the temperature range from 498 to 593 K.

  7. Hot Wire Needle Probe for In-Pile Thermal Conductivity Detection

    SciTech Connect

    Joshua Daw; Joy Rempe; Keith Condie; Darrell Knudson; S. Curtis Wilkins; Brandon S. Fox; Heng Ban

    2001-11-01

    Thermal conductivity is a key property of interest for both nuclear fuel and structural materials, and must be known for proper design, test, and application of new fuels and structural materials in nuclear reactors. Thermal conductivity is highly dependent on the physical structure, chemical composition, and the state of the material. Typically, thermal conductivity changes that occur during irradiation are measured out-of-pile by Post Irradiated Examination (PIE) using a “cook and look” approach in hot-cells. Repeatedly removing samples from a test reactor to make out-of-pile measurements is expensive, has the potential to disturb phenomena of interest, and only provides understanding of the sample's end state at the time each measurement is made. There are also limited thermophysical property data for advanced fuels. Such data are needed for simulation design codes, the development of next generation reactors, and advanced fuels for existing nuclear plants. Being able to quickly characterize fuel thermal conductivity during irradiation can improve the fidelity of data, reduce costs of post-irradiation examinations, increase understanding of how fuels behave under irradiation, and confirm or improve existing thermal conductivity measurement techniques. This paper discusses advancements from Idaho National Laboratory (INL) / Utah State University (USU) examinations, including background information, governing equations, experimental setup, detailed results, and conclusions for both a steady state and a transient method. Experimental findings of the INL/USU steady state method examinations help to better understand limitations and benefits of two-thermocouple methods, where laboratory results can be extrapolated to in-pile applications. Additionally, results from the transient method offer the immediate potential for in-pile application, as the method reduces the impact on the sample from only a small centerline sensor, measurement times (e.g., only minutes for

  8. The four spot time-of-flight laser anemometer

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1985-01-01

    The newly constructed, four-spot anemometer was shown to perform as predicted. The new anemometer's measurement region has the required characteristics: wide acceptance angle and high spatial selectivity to permit measurements in turbulent, hostile environments.

  9. Relationship of roughness of building stones on the effective thermal conductivity determined by transient hot-wire method

    NASA Astrophysics Data System (ADS)

    Benoit, Merckx; Jean-Didier, Mertz; Patrick, Dudoignon; David, Giovannacci; Jean-Philippe, Garnier

    2013-04-01

    Alteration of inorganic materials in monuments is mainly related to relative humidity change in the porous network. Characterization of water content is a complex issue, specially in case of non-intrusive measurement. An innovative method is developed to quantify the water content using a direct calculation of the thermal conductivity. In order to validate the non-intrusive application to heritage stone, a control of the influence of the rock-sensor interface is required. The study was carried out on five sedimentary french rocks : three limestones (lithographic, oolithic and micritic), a sandstone of Fontainebleau and the so-called Tuffeau limestone. The textural properties are characterized by optical and electronical microscopy, X-ray diffraction, and mercury intrusion porosimetry. The transient hot-wire method is useful to obtain a quick value of effective conductivity of material. Initially used in liquids and gas, It's now more and more used for solid materials. The calculation of one effective thermal conductivity is formulated by the slope of recorded DT/ln(t) diagrams. In case of continuous and homogeneous media, only one slope can be measured. For heterogeneous solids a typical curve present two slopes : the first one measured in the short time acquisitions (<1s) mainly depends on the contact between the wire and grains and thus micro texture of the material. The second one, measured for longer time acquisitions, characterizes the mean effective thermal conductivity of the material. In the case of surface measurement, the first part of curve is relevant from the texture and roughness of the material. Roughness properties are determined by an interferometer system on different polished surfaces of the materials. For all studied stones, the arithmetic average roughness (Sa) is ranged between 44 µm and 1 µm, respectively for the coarse-grained limestone (Bretigny) and the finest one (Migné). According to the relative error of the apparatus (10%), the

  10. Industry guidelines for the calibration of maximum anemometers

    SciTech Connect

    Bailey, B.H.

    1996-12-31

    The purpose of this paper is to report on a framework of guidelines for the calibration of the Maximum Type 40 anemometer. This anemometer model is the wind speed sensor of choice in the majority of wind resource assessment programs in the U.S. These guidelines were established by the Utility Wind Resource Assessment Program. In addition to providing guidelines for anemometers, the appropriate use of non-calibrated anemometers is also discussed. 14 refs., 1 tab.

  11. Tracing Rays In Laser-Fringe Anemometers

    NASA Technical Reports Server (NTRS)

    Owen, Karl

    1989-01-01

    "OPTMAIN" is simple ray-tracing computer code developed to quantify refractive effects that result when laser-fringe anemometer used to observe flows through window. Code calculates changes for four different types of windows: flat-plate windows, simple cylindrical windows, "general" axisymmetric windows, and smooth general-surface windows. Written in FORTRAN IV.

  12. New devices for flow measurements: Hot film and burial wire sensors, infrared imagery, liquid crystal, and piezo-electric model

    NASA Technical Reports Server (NTRS)

    Mcree, Griffith J., Jr.; Roberts, A. Sidney, Jr.

    1991-01-01

    An experimental program aimed at identifying areas in low speed aerodynamic research where infrared imaging systems can make significant contributions is discussed. Implementing a new technique, a long electrically heated wire was placed across a laminar flow. By measuring the temperature distribution along the wire with the IR imaging camera, the flow behavior was identified.

  13. Considerations for Calibrating a Laser Doppler Anemometer

    SciTech Connect

    Duncan, Michael L; Keck, Joe

    2010-01-01

    Laser Doppler Anemometers have long been the device-of-choice for air velocity measurements due to their avoidance of turbulence induced by insertion-method air velocity measurement devices. At first glance, the use of a Laser Doppler Anemometer (LDA) for calibrating air velocity meters appears to be a relatively simple and straightforward process. As is typical in most metrological applications the process becomes much more complex when attempting to use the apparatus to make high-performance, metrology measurements. This paper focuses on the considerations for calibration of a LDA beginning with a discussion why an LDA needs to be calibrated. Other areas of discussion include alignment of the optics, dealing with imperfections in the alignment process, establishing the traceability of measurements from the apparatus and design and development of and experiences with using a calibration apparatus.

  14. Quality, precision and accuracy of the maximum No. 40 anemometer

    SciTech Connect

    Obermeir, J.; Blittersdorf, D.

    1996-12-31

    This paper synthesizes available calibration data for the Maximum No. 40 anemometer. Despite its long history in the wind industry, controversy surrounds the choice of transfer function for this anemometer. Many users are unaware that recent changes in default transfer functions in data loggers are producing output wind speed differences as large as 7.6%. Comparison of two calibration methods used for large samples of Maximum No. 40 anemometers shows a consistent difference of 4.6% in output speeds. This difference is significantly larger than estimated uncertainty levels. Testing, initially performed to investigate related issues, reveals that Gill and Maximum cup anemometers change their calibration transfer functions significantly when calibrated in the open atmosphere compared with calibration in a laminar wind tunnel. This indicates that atmospheric turbulence changes the calibration transfer function of cup anemometers. These results call into question the suitability of standard wind tunnel calibration testing for cup anemometers. 6 refs., 10 figs., 4 tabs.

  15. Effect of cooling rate after hot rolling and of multistage strain aging on the drawability of low-carbon-steel wire rod

    NASA Astrophysics Data System (ADS)

    Taheri, A. Karimi; Maccagno, T. M.; Jonas, J. J.

    1995-05-01

    Tensile testing was used to simulate the multistage strain aging occurring in low-C steel during the relatively short intervals between dies in a multiple-die wire-drawing machine. The effects were examined of three simulated post-hot-rolling cooling rates and three thermal treatments on the strain-aging susceptibility of a high- and a low-N steel. This was measured by applying a 6 pct tensile strain, followed by aging at either 65° or 100 °C for 20 seconds, and then pulling the specimen to failure at room temperature. Increases in flow stress and decreases in the elongation to fracture both indicated high susceptibility to strain aging. It was found that the nitrogen content, the cooling rate from the hot-rolling temperature to about 300 °C, as well as the cooling rate below 300 °C, all have dramatic effects on the strain-aging behavior. Moreover, multistage strain aging is more severe than single-stage strain aging. The implications of these observations on increasing the drawability of low-carbon-steel wire are discussed.

  16. Aerodynamic Analysis of Cup Anemometers Performance: The Stationary Harmonic Response

    PubMed Central

    Pindado, Santiago; Cubas, Javier; Sanz-Andrés, Ángel

    2013-01-01

    The effect of cup anemometer shape parameters, such as the cups' shape, their size, and their center rotation radius, was experimentally analyzed. This analysis was based on both the calibration constants of the transfer function and the most important harmonic term of the rotor's movement, which due to the cup anemometer design is the third one. This harmonic analysis represents a new approach to study cup anemometer performances. The results clearly showed a good correlation between the average rotational speed of the anemometer's rotor and the mentioned third harmonic term of its movement. PMID:24381512

  17. Mobile fiber-optic laser Doppler anemometer.

    PubMed

    Stieglmeier, M; Tropea, C

    1992-07-20

    A laser Doppler anemometer (LDA) has been developed that combines the compactness and low power consumption of laser diodes and avalanche photodiodes with the flexibility and possibility of miniaturization by using fiber-optic probes. The system has been named DFLDA for laser diode fiber LDA and is especially suited for mobile applications, for example, in trains, airplanes, or automobiles. Optimization considerations of fiber-optic probes are put forward and several probe examples are described in detail. Measurement results from three typical applications are given to illustrate the use of the DFLDA. Finally, a number of future configurations of the DFLDA concept are discussed.

  18. Sonic anemometers in aeolian sediment transport research

    NASA Astrophysics Data System (ADS)

    van Boxel, J. H.; Sterk, G.; Arens, S. M.

    2004-04-01

    Fast-response wind and turbulence instruments, including sonic anemometers, are used more and more in aeolian sediment transport research. These instruments give information on mean wind, but also on fluctuations and turbulent statistics, such as the uw covariance, which is a direct measure of Reynolds' stress (RS) and friction velocity. This paper discusses the interpretation of sonic anemometer data, the transformations needed to get proper results and turbulence spectra, and how they are influenced by instrument size, sampling frequency, and measurement height. Turbulence spectra characterize how much the different frequencies in the turbulent signals contribute to the variance of wind speed, or to the covariance of horizontal and vertical wind speed. They are important in determining the measurement strategy when working with fast-response instruments, such as sonic anemometers, and are useful for interpreting the measurement results. Choices on the type of sonic anemometer, observation height, sampling period, sampling frequency, and filtering can be made on the basis of expected high and low-frequency losses in turbulent signals, which are affected by those variables, as well as wind speed and atmospheric stability. Friction velocity and RS, important variables in aeolian sediment transport research, are very sensitive to tilt or slope errors. During a field experiment, the slope sensitivity of the RS was established as 9% per degree of slope, which is 1.5 times the value reported in literature on the basis of theoretical considerations. An important reason for the difference probably is the large influence of streamline curvature on turbulence statistics and thereby on the slope sensitivity of the RS. An error of 9% per degree of slope in the RS will translate into an error of approximately 4% per degree of slope in the calculated friction velocity. Space-time correlation of the horizontal wind speed is much larger than that of the vertical wind speed and

  19. Three-component laser anemometer measurement systems

    NASA Technical Reports Server (NTRS)

    Goldman, Louis J.

    1991-01-01

    A brief overview of the different laser anemometer (LA) optical designs available is presented. Then, the LA techniques that can be used to design a three-component measurement system for annular geometries are described. Some of the facility design considerations unique to these LA systems are also addressed. Following this, the facilities and the LA systems that were used to successfully measure the three components of velocity in the blading of annular-flow machines are reviewed. Finally, possible LA system enhancements and future research directions are presented.

  20. Use of PIV to highlight possible errors in hot-wire Reynolds stress data over a 2D rough wall

    NASA Astrophysics Data System (ADS)

    Djenidi, Lyazid; Antonia, Robert A.; Amielh, Muriel; Anselmet, Fabien

    2014-10-01

    Particle image velocimetry (PIV) measurements are carried out in a turbulent boundary layer over a 2D rough surface consisting of transverse square bars. The aim of this work is to investigate a possible cause for the near-wall X-wire measurement errors observed on similar rough surfaces. The PIV measurements do not show the anomalous near-wall deficit of Reynolds stresses as measured with X-wires over the same surface. An extensive flow visualization analysis of the PIV data for a spacing between the roughness elements of p = 7 k ( k is the roughness element height) shows the occurrence of large-scale inward (sweeps) and outward (ejections) motions with a period of about 10.6 δ/ U 0 ( δ and U 0 are the boundary layer thickness and the free-stream velocity). While these motions dominate the near-wall region and contribute almost equally to the Reynolds shear stress -‹ uv›, the mean outward deviation from the mean flow direction is stronger than the inward deviation. Also, when the roughness spacing is reduced to p = 3 k, the outward deviation reduces significantly more than the inward deviation. The results support the argument that the outward motions, which can have an instantaneous deviation angle of more than 50° in the case p = 7 k, make the X-wire probe inefficient for detecting the ejection events (associated with the outward motions), particularly if the apex angle of the X-wire is not optimized for capturing the strong flow ejections with large deviations. The results explain in part the disparate information on the effect of the roughness on the Reynolds stresses in the outer region of the turbulent boundary layer over rough walls.

  1. The influence of hydrogen dilution and substrate temperature in hot-wire deposition of amorphous and microcrystalline silicon with filament temperatures between 1900 and 2500 C

    SciTech Connect

    Conde, J.P.; Brogueira, P.; Castanha, R.; Chu, V.

    1996-12-31

    The effect of hydrogen dilution and substrate temperature on the optoelectronic and structural properties of thin films deposited by hot-wire chemical vapor deposition with filament temperatures between 1,900 and 2,500 C from silane and hydrogen are studied. Amorphous silicon films are obtained at high deposition rates for hydrogen dilutions below 90%. The deposition rate scales approximately linearly with the filament temperature in this regime. Microcrystalline films are obtained for hydrogen dilution above 90%, independently of the filament temperature and substrate temperature, with much lower growth rates. The Raman spectrum of these films shows high crystalline fraction and small grain size. High conductivity films, typical of microcrystalline silicon, with high growth rates were achieved by either increasing the substrate temperature at low hydrogen dilution, or by using a hydrogen dilution just at the amorphous to microcrystalline transition point.

  2. Comparative Study of Solid-Phase Crystallization of Amorphous Silicon Deposited by Hot-Wire CVD, Plasma-Enhanced CVD, and Electron-Beam Evaporation

    SciTech Connect

    Stradins, P.; Kunz, O.; Young, D. L.; Yan, Y.; Jones, K. M.; Xu, Y.; Reedy, R. C.; Branz, H. M.; Aberle, A. G.; Wang, Q.

    2007-01-01

    Solid-phase crystallization (SPC) rates are compared in amorphous silicon films prepared by three different methods: hot-wire chemical vapor deposition (HWCVD), plasma-enhanced chemical vapor deposition (PECVD), and electron-beam physical vapor deposition (e-beam). Random SPC proceeds approximately 5 and 13 times slower in PECVD and e-beam films, respectively, as compared to HWCVD films. Doping accelerates random SPC in e-beam films but has little effect on the SPC rate of HWCVD films. In contrast, the crystalline growth front in solid-phase epitaxy experiments propagates at similar speed in HWCVD, PECVD, and e-beam amorphous Si films. This strongly suggests that the observed large differences in random SPC rates originate from different nucleation rates in these materials while the grain growth rates are relatively similar. The larger grain sizes observed for films that exhibit slower random SPC support this suggestion.

  3. Calibration and Lag of a Friez Type Cup Anemometer

    NASA Technical Reports Server (NTRS)

    Pinkerton, Robert M

    1930-01-01

    Tests on a Friez type cup anemometer have been made in the variable density wind tunnel of the Langley Memorial Aeronautical Laboratory to calibrate the instrument and to determine its suitability for velocity measurements of wind gusts. The instrument was calibrated against a Pitot-static tube placed directly above the anemometer at air densities corresponding to sea level, and to an altitude of approximately 6000 feet. Air-speed acceleration tests were made to determine the lag in the instrument reading. The calibration results indicate that there should be an altitude correction. It is concluded that the cup anemometer is too sluggish for velocity measurements of wind gusts.

  4. Wind Powering America Anemometer Loan Program: A Retrospective

    SciTech Connect

    Jimenez, T.

    2013-05-01

    This white paper details the history, mechanics, status, and impact of the Native American Anemometer Loan Program (ALP) conducted by the U.S. Department of Energy's Wind Powering America (WPA) initiative. Originally conceived in 2000 and terminated (as a WPA activity) at the end of FY 2011, the ALP has resulted in the installation of anemometers at 90 locations. In addition, the ALP provided support for the installation of anemometers at 38 additional locations under a related ALP administered by the Western Area Power Administration.

  5. Fast-response cup anemometer features cosine response

    NASA Technical Reports Server (NTRS)

    Frenzen, P.

    1968-01-01

    Six-cup, low-inertia anemometer combines high resolution and fast response with a unique ability to sense only the horizontal component of the winds fluctuating rapidly in three dimensions. Cup assemblies are fabricated of expanded polystyrene plastic.

  6. Investigation of thermal and hot-wire chemical vapor deposition copper thin films on TiN substrates using CupraSelect as precursor.

    PubMed

    Papadimitropoulos, G; Davazoglou, D

    2011-09-01

    Copper films were deposited on oxidized Si substrates covered with TiN using a novel chemical vapor deposition reactor in which reactions were assisted by a heated tungsten filament (hot-wire CVD, HWCVD). Liquid at room temperature hexafluoroacetylacetonate Cu(I) trimethylvinylsilane (CupraSelect) was directly injected into the reactor with the aid of a direct-liquid injection (DLI) system using N2 as carrier gas. The deposition rates of HWCVD Cu films obtained on TiN covered substrates were found to increase with filament temperature (65 and 170 degrees C were tested). The resistivities of HWCVD Cu films were found to be higher than for thermally grown films due to the possible presence of impurities into the Cu films from the incomplete dissociation of the precursor and W impurities caused by the presence of the filament. For HWCVD films grown at a filament temperature of 170 degrees C, smaller grains are formed than at 65 degrees C as shown from the taken SEM micrographs. XRD diffractograms taken on Cu films deposited on TiN could not reveal the presence of W compounds originating from the filament because the relative peak was masked by the TiN [112] peak. PMID:22097549

  7. Nanocrystalline Si/SiO{sub 2} core-shell network with intense white light emission fabricated by hot-wire chemical vapor deposition

    SciTech Connect

    Matsumoto, Y. Dutt, A.; Santana-Rodríguez, G.; Santoyo-Salazar, J.; Aceves-Mijares, M.

    2015-04-27

    We report the fabrication of a stable Si/SiO{sub 2} core-shell network using hot-wire chemical vapor deposition on a silicon substrate at a relatively low substrate temperature of 200 °C. Structural investigations using transmission electron microscopy and X-ray diffraction confirm the presence of nanocrystalline silicon and silicon dioxide quantum dots in the form of a core-shell network embedded in the amorphous SiO{sub x} matrix, while selected area electron diffraction confirms the formation of a core-shell structure. The core-shell structure exhibits a bright white emission that can be seen with the unaided eye at room temperature without any post-annealing treatments, and the observed photoemission does not alter in color or intensity after prolonged laser exposure. Additional measurements are performed while varying the laser power and optical gain is found in the as-deposited material. Intense stable white luminescence is observed and shows the prospective for various optical and biological applications in the future.

  8. The influence of charge effect on the growth of hydrogenated amorphous silicon by the hot-wire chemical vapor deposition technique

    SciTech Connect

    Wang, Q.; Nelson, B.P.; Iwaniczko, E.; Mahan, A.H.; Crandall, R.S.; Benner, J.

    1998-09-01

    The authors observe at lower substrate temperatures that the scatter in the dark conductivity on hydrogenated amorphous silicon (a-Si:H) films grown on insulating substrates (e.g., Corning 7059 glass) by the hot-wire chemical vapor deposition technique (HWCVD) can be five orders of magnitude or more. This is especially true at deposition temperatures below 350 C. However, when the authors grow the same materials on substrates with a conductive grid, virtually all of their films have acceptable dark conductivity (< 5 {times} 10{sup {minus}10} S/cm) at all deposition temperatures below 425 C. This is in contrast to only about 20% of the materials grown in this same temperature range on insulating substrates having an acceptable dark conductivity. The authors estimated an average energy of 5 eV electrons reaching the growing surface in vacuum, and did additional experiments to see the influence of both the electron flux and the energy of the electrons on the film growth. Although these effects do not seem to be important for growing a-Si:H by HWCVD on conductive substrates, they help better understand the important parameters for a-Si:H growth, and thus, to optimize these parameters in other applications of HWCVD technology.

  9. A flying hot wire study of the turbulent near wake of a circular cylinder at Reynolds number of 140,000. Ph.D. Thesis. Progress Report

    NASA Technical Reports Server (NTRS)

    Cantwell, B. J.

    1975-01-01

    The phenomenology was studied of the processes of vortex formation and transport in the near wake, at a Reynolds number sufficiently high to insure a fully turbulent wake, but low enough to insure a laminar separation. The apparatus developed for measuring this flow consisted of X-array hot wire probes mounted on the ends of a pair of whirling arms. A computer controlled data acquisition system was slaved to the position of the rotating arm and managed, monitored, edited, and recorded the vast profusion of data which is continuously poured out by the device. Results are presented which show the instantaneous velocity, intermittency, vorticity, and stress fields as a function of phase for the first six diameters of the near wake. The stresses in the near wake emerge as a concatenation of peaks and valleys, some the result of strong induced motions in the outer flow which cause free stream fluid to move rapidly inward toward the center of the wake, others the result of the random motions of the background turbulence.

  10. Ultrasonic anemometer angle of attack errors under turbulent conditions

    NASA Astrophysics Data System (ADS)

    Nakai, T.

    2009-12-01

    Measurements of eddy fluxes are premised on the assumption that wind speeds are measured accurately by an ultrasonic anemometer. Recently, ultrasonic anemometers have been shown to suffer errors depending on the angle of attack, which is the angle between the wind vector and the horizontal. The correction of these errors resulted in general increases in eddy fluxes. However, since the check of the angle of attack dependent error was carried out in the wind tunnel experiment, which would be under the condition of nearly laminar flow, the applicability of this correction to the field data under turbulent conditions has been questioned. In this study, angle of attack dependencies of wind speeds measured by Gill Windmaster ultrasonic anemometers were assessed by field experiment over meadow, considered to be turbulent conditions. By using five identical anemometers, two pairs of systems were prepared: two anemometers for references and one between them for tilt. The dependencies of (co)sine responses of anemometers on angles of attack of 0 to -90 degrees in 10-degree steps and 45 degrees were checked, and clarified that the angle of attack dependent errors occur also under turbulent conditions, with results similar to the wind tunnel experiments. Sine responses of vertical wind speeds depended not only on vertical angle of attack but also on horizontal wind direction, which had not been considered in previous studies. For more robust correction, alternative calibration functions were obtained empirically so as to reasonably explain our field experimental results. Applying this new correction, eddy fluxes increased substantially even over meadow, which is somewhat aerodynamically smooth compared with forests or agricultural fields.

  11. Single and multijunction silicon based thin film solar cells on a flexible substrate with absorber layers made by hot-wire CVD

    NASA Astrophysics Data System (ADS)

    Li, Hongbo

    2007-09-01

    With the worldwide growing concern about reliable energy supply and the environmental problems of fossil and nuclear energy production, the need for clean and sustainable energy sources is evident. Solar energy conversion, such as in photovoltaic systems, can play a major role in the urgently needed energy transition in electricity production. Solar cells based on thin film silicon and its alloys are a promising candidate that is capable of fulfilling the fast increasing demand of a reliable solar cell supply. The conventional method to deposit silicon thin films is based on plasma enhanced chemical vapour deposition (PECVD) techniques, which have the disadvantage of increasing film inhomogeneity at a high deposition rate when scaling up for the industrial production. In this thesis, we study the possibility of making high efficiency single and multijunction thin film silicon solar cells with the so-called hot-wire CVD technique, in which no strong electromagnetic field is involved in the deposition. Therefore, the up-scaling for industrial production is straightforward. We report and discuss our findings on the correlation of substrate surface rms roughness and the main output parameter of a solar cell, the open circuit voltage Voc of c-Si:H n i p cells. By considering all the possible reasons that could influence the Voc of such cells, we conclude that the near linear correlation of Voc and substrate surface rms roughness is the result the two most probable reasons: the unintentional doping through the cracks originated near the valleys of the substrate surface due to the in-diffusion of impurities, and the high density electrical defects formed by the collision of columnar silicon structures. Both of them relate to the morphology of substrate surface. Therefore, to have the best cell performance on a rough substrate surface, a good control on the substrate surface morphology is necessary. Another issue influencing the performance of c-Si:H solar cells is the

  12. Deposition of microcrystalline silicon prepared by hot-wire chemical-vapor deposition: The influence of the deposition parameters on the material properties and solar cell performance

    NASA Astrophysics Data System (ADS)

    Klein, Stefan; Finger, Friedhelm; Carius, Reinhard; Stutzmann, Martin

    2005-07-01

    Microcrystalline silicon (μc-Si:H) of superior quality can be prepared using the hot-wire chemical-vapor deposition method (HWCVD). At a low substrate temperature (TS) of 185 °C excellent material properties and solar cell performance were obtained with spin densities of 6×1015cm-3 and solar cell efficiencies up to 9.4%, respectively. In this study we have systematically investigated the influence of various deposition parameters on the deposition rate and the material properties. For this purpose, thin films and solar cells were prepared at specific substrate and filament temperatures and deposition pressures (pD), covering the complete range from amorphous to highly crystalline material by adjusting the silane concentration. The influence of these deposition parameters on the chemical reactions at the filament and in the gas phase qualitatively explains the behavior of the structural composition and the formation of defects. In particular, we propose that the deposition rate is determined by the production of reactive species at the filament and a particular atomic-hydrogen-to-silicon ratio is found at the microcrystalline/amorphous transition. The structural, optical, and electronic properties were studied using Raman and infrared spectroscopies, optical-absorption measurements, electron-spin resonance, and dark and photoconductivities. These experiments show that higher TS and pD lead to a deterioration of the material quality, i.e., much higher defect densities, oxygen contaminations, and SiH absorption at 2100cm-1. Similar to plasma enhanced chemical-vapor deposition material, μc-Si:H solar cells prepared with HW i layers show increasing open circuit voltages (Voc) with increasing silane concentration and best performance is achieved near the transition to amorphous growth. Such solar cells prepared at low TS exhibit very high Voc up to 600 mV and fill factors above 70% with i layers prepared by HWCVD.

  13. Method of manufacturing superconductor wire

    SciTech Connect

    Motowidlo, Leszek

    2014-09-16

    A method for forming Nb.sub.3Sn superconducting wire is provided. The method employs a powder-in-tube process using a high-tin intermetallic compound, such as MnSn.sub.2, for producing the Nb.sub.3Sn. The use of a high-tin intermetallic compound enables the process to perform hot extrusion without melting the high-tin intermetallic compound. Alternatively, the method may entail drawing the wire without hot extrusion.

  14. Basic Wiring.

    ERIC Educational Resources Information Center

    Kaltwasser, Stan; And Others

    This module is the first in a series of three wiring publications; it serves as the foundation for students enrolled in a wiring program. It is a prerequisite to either "Residential Wiring" or "Commercial and Industrial Wiring." The module contains 16 instructional units that cover the following topics: occupational introduction; general safety;…

  15. The critical parameters in in-situ MgB2 wires and tapes with ex-situ MgB2 barrier after hot isostatic pressure, cold drawing, cold rolling and doping

    NASA Astrophysics Data System (ADS)

    Gajda, D.; Morawski, A.; Zaleski, A. J.; Häßler, W.; Nenkov, K.; Rindfleisch, M. A.; Żuchowska, E.; Gajda, G.; Czujko, T.; Cetner, T.; Hossain, M. S. A.

    2015-05-01

    MgB2 precursor wires were prepared using powder in tube technique by Institute of High Pressure PAS in Warsaw. All samples were annealed under isostatic pressure generated by liquid Argon in the range from 0.3 GPa to 1 GPa. In this paper, we show the effects of different processing routes, namely, cold drawing (CD), cold rolling (CR), hot isostatic pressure (HIP) and doping on critical current density (Jc), pinning force (Fp), irreversible magnetic-field (Birr), critical temperature (Tc), n value, and dominant pinning mechanism in MgB2/Fe wires with ex situ MgB2 barrier. The results show that medium pressures (˜0.35 GPa) lead to high Jc in low and medium magnetic fields (0 T - 9 T). On the other hand, higher pressures (˜1 GPa) lead to enhanced Jc in high magnetic fields (above 9 T). Transport measurements show that CD, CR, and HIP have small effects on Birr and Tc, but CD, CR, HIP, and doping enhance Jc and Fp in in situ MgB2 wires with ex situ MgB2 barrier. Transport measurements on in situ undoped MgB2 wire with ex situ MgB2 barrier yield a Jc of about 100 A/mm2 at 4.2 K in 6 T, at 10 K in 4 T and at 20 K in 2 T. The results also show that cold drawing causes increase of n value.

  16. Evaluation of a new sonic anemometer for routine monitoring and emergency response applications

    SciTech Connect

    Gouveia, F.J; Baskett, R.L.

    1997-02-01

    Recently, several new sonic anemometers have become available for routine wind measurements. Sonic anemometers avoid many problems associated with the traditional rotating anemometer and vane sets- inertia of moving parts, bearing wear, contamination from dust and ice, frequent maintenance. Without a starting threshold, the sonic anemometer also produces more accurate measurements of wind direction and sigma theta at very low wind speeds. We illustrate these advantages by comparing 20 days of observations from a new sonic anemometer with data from existing cup and vane sensors at the 10-m level of Lawrence Livermore National Laboratory`s meteorological tower.

  17. The Cup Anemometer, a Fundamental Meteorological Instrument for the Wind Energy Industry. Research at the IDR/UPM Institute

    PubMed Central

    Pindado, Santiago; Cubas, Javier; Sorribes-Palmer, Félix

    2014-01-01

    The results of several research campaigns investigating cup anemometer performance carried out since 2008 at the IDR/UPM Institute are included in the present paper. Several analysis of large series of calibrations were done by studying the effect of the rotor's geometry, climatic conditions during calibration, and anemometers' ageing. More specific testing campaigns were done regarding the cup anemometer rotor aerodynamics, and the anemometer signals. The effect of the rotor's geometry on the cup anemometer transfer function has been investigated experimentally and analytically. The analysis of the anemometer's output signal as a way of monitoring the anemometer status is revealed as a promising procedure for detecting anomalies. PMID:25397921

  18. The cup anemometer, a fundamental meteorological instrument for the wind energy industry. Research at the IDR/UPM Institute.

    PubMed

    Pindado, Santiago; Cubas, Javier; Sorribes-Palmer, Félix

    2014-11-12

    The results of several research campaigns investigating cup anemometer performance carried out since 2008 at the IDR/UPM Institute are included in the present paper. Several analysis of large series of calibrations were done by studying the effect of the rotor's geometry, climatic conditions during calibration, and anemometers' ageing. More specific testing campaigns were done regarding the cup anemometer rotor aerodynamics, and the anemometer signals. The effect of the rotor's geometry on the cup anemometer transfer function has been investigated experimentally and analytically. The analysis of the anemometer's output signal as a way of monitoring the anemometer status is revealed as a promising procedure for detecting anomalies.

  19. Method of Assembling a Silicon Carbide High Temperature Anemometer

    NASA Technical Reports Server (NTRS)

    Okojie, Robert S. (Inventor); Fralick, Gustave C. (Inventor); Saad, George J. (Inventor)

    2004-01-01

    A high temperature anemometer includes a pair of substrates. One of the substrates has a plurality of electrodes on a facing surface, while the other of the substrates has a sensor cavity on a facing surface. A sensor is received in the sensor cavity, wherein the sensor has a plurality of bondpads, and wherein the bondpads contact the plurality of electrodes when the facing surfaces are mated with one another. The anemometer further includes a plurality of plug-in pins, wherein the substrate with the cavity has a plurality of trenches with each one receiving a plurality of plug-in pins. The plurality of plug-in pins contact the plurality of electrodes when the substrates are mated with one another. The sensor cavity is at an end of one of the substrates such that the sensor partially extends from the substrate. The sensor and the substrates are preferably made of silicon carbide.

  20. All semiconductor laser Doppler anemometer at 1.55 microm.

    PubMed

    Hansen, René Skov; Pedersen, Christian

    2008-10-27

    We report to our best knowledge the first all semiconductor Laser Doppler Anemometer (LIDAR) for wind speed determination. We will present the design and first experimental results on a focusing coherent cw laser Doppler anemometer for measuring atmospheric wind velocities in the 10 meters to 300 meters distance range. Especially, we will demonstrate that both the output power as well as the demanding coherence properties required from the laser source can be accomplished by an all semiconductor laser. Preliminary tests at a distance of 40 meters indicate a typical signal to noise ratio of 9 dB. This result is obtained at a clear day with an up-date rate of 12 Hz.

  1. All semiconductor laser Doppler anemometer at 1.55 microm.

    PubMed

    Hansen, René Skov; Pedersen, Christian

    2008-10-27

    We report to our best knowledge the first all semiconductor Laser Doppler Anemometer (LIDAR) for wind speed determination. We will present the design and first experimental results on a focusing coherent cw laser Doppler anemometer for measuring atmospheric wind velocities in the 10 meters to 300 meters distance range. Especially, we will demonstrate that both the output power as well as the demanding coherence properties required from the laser source can be accomplished by an all semiconductor laser. Preliminary tests at a distance of 40 meters indicate a typical signal to noise ratio of 9 dB. This result is obtained at a clear day with an up-date rate of 12 Hz. PMID:18958105

  2. Wind speed statistics for Goldstone, California, anemometer sites

    NASA Technical Reports Server (NTRS)

    Berg, M.; Levy, R.; Mcginness, H.; Strain, D.

    1981-01-01

    An exploratory wind survey at an antenna complex was summarized statistically for application to future windmill designs. Data were collected at six locations from a total of 10 anemometers. Statistics include means, standard deviations, cubes, pattern factors, correlation coefficients, and exponents for power law profile of wind speed. Curves presented include: mean monthly wind speeds, moving averages, and diurnal variation patterns. It is concluded that three of the locations have sufficiently strong winds to justify consideration for windmill sites.

  3. Calibration data for improved correction of uvw propeller anemometers

    SciTech Connect

    Connell, J.R. ); Morris, V.R. )

    1991-10-01

    Wind turbine test programs sponsored by the US DOE in the late 1980s called for measurement of three-dimensional turbulent wind with an accuracy not previously required. The Pacific Northwest Laboratory identified the need for more complete, more highly resolved, and more accurate calibrations to provide the new level of measurement capability. The uvw propeller anemometer, became the object of a unique calibration effort at a large wind tunnel at Colorado State University. A uvw anemometer, will all three propellers active, was installed in the wind tunnel on a digitally stepped two-axis rotary platform placed just below the tunnel floor. The azimuth and elevation of the anemometer in a steady wind at each of a selected set of speeds was stepped through a complete test program using a digital computer as controller and a digital data acquisition system to sample and filter the data. Tests were run using polypropylene and carbon fiber propellers. In addition, the effects of attaching shaft extensions'' to the polypropylene propellers were measured. Calibrations for the polypropylene four-blade propeller provide an improved level of detail and repeatability. The uvw propeller anemometer is quite accurate at all wind angles and speeds to be experienced in wind energy studies, including winds blowing at right angles to the axis of rotation of a propeller. The new correction factors derived from these data eliminate previous difficulties in accuracy and speed of data reduction from voltages to wind speed components. Calibration data for a carbon-fiber thermoplastic propeller are presented with resolution similar to that for the polypropylene propellers. 8 refs., 15 figs., 1 tab.

  4. SiC-Based Miniature High-Temperature Cantilever Anemometer

    NASA Technical Reports Server (NTRS)

    Okojie, Robert S.; Fralick, Gustave; Saad, George J.

    2004-01-01

    The figure depicts a miniature cantilever-type anemometer that has been developed as a prototype of compact, relatively nonintrusive anemometers that can function at temperatures up to 600 C and that can be expected to be commercially mass-producible at low cost. The design of this anemometer, and especially the packaging aspect of the design, is intended to enable measurement of turbulence in the high-temperature, high-vibration environment of a turbine engine or in any similar environment. The main structural components of the anemometer include a single-crystal SiC cantilever and two polycrystalline SiC clamping plates, all made from chemical-vapor-deposited silicon carbide. Fabrication of these components from the same basic material eliminates thermal-expansion mismatch, which has introduced spurious thermomechanical stresses in cantilever-type anemometers of prior design. The clamping plates are heavily oxidized to improve electrical insulation at high temperature. A cavity that serves as a receptacle for the clamped end of the cantilever is etched into one end of one clamping plate. Trenches that collectively constitute a socket for a multipin electrical plug (for connection to external electronic circuitry) are etched into the opposite end of this clamping plate. Metal strips for electrical contact are deposited on one face of the other clamping plate. Piezoresistive single-crystal SiC thin-film strain gauges are etched in the n-type SiC epilayer in a Wheatstone-bridge configuration. Metal contact pads on the cantilever that extend into the clamping-receptacle area, are obtained by deposition and patterning using standard semiconductor photolithography and etching methods. The cantilever and the two clamping plates are assembled into a sandwich structure that is then clamped in a stainless-steel housing. The Wheatstone- bridge carrying SiC cantilever with the metal contact pads on the piezoresistors is slid into the receptacle in the bottom clamping plate

  5. Precise Wireless Triggering System for Anemometers with Long-Baseline Acoustic Probes

    NASA Astrophysics Data System (ADS)

    Naoto Wakatsuki,; Shin Kinjo,; Jun Takarada,; Koichi Mizutani,

    2010-07-01

    A wireless triggering system for acoustic anemometers using an acoustic probe with a long baseline is investigated. Acoustic probes for measuring micrometeorologic parameters, such as temperature and wind velocity, are used as noncontact and nondestructive methods. The acoustic probe with a long baseline was previously proposed by the authors and investigated to form a sensing grid system for micrometeorologic measurement. The authors have also partially investigated a wireless sensing grid using a wireless local-area network (LAN). However, because of the synchronization problem between sensor nodes, the trigger line has been left wired. In this paper, the problem of synchronization is solved by investigating a wireless triggering system using frequency modulated (FM) radio waves. The primitive triggering system of FM radio waves has some instability on time synchronization depending on such the communication environment as signal-to-noise ratio (SNR). To overcome the influence of the instability, a cross-correlation method is adopted to the triggering system. As a result, the time synchronization errors of the trigger system were reduced by up to one tenth. In addition, not only the instability problem but also other larger errors are compensated by the proposed system in an experimental wind velocity measurement.

  6. Tungsten wire for incandescent lamps

    SciTech Connect

    Walter, J.L.; Briant, C.L. )

    1990-09-01

    Tungsten wire for incandescent lamp filaments must operate at high temperatures and for long times. To meet these requirements, the grain morphology of the wire must be controlled to reduce the propensity for grain boundary sliding. The morphology is a function of the distribution of very small pockets of potassium in the wire and the mechanical processing from ingot to wire. The behavior of the filament is directly related to the grain morphology. This paper describes the mechanism by which the potassium is incorporated into and distributed in the ingot. The elongation and spheroidization of the bubbles during hot rolling and swaging is also examined and related to the grain morphology of wire. Some indications of the relationship between grain morphology and filament behavior are also given.

  7. Wire chamber

    DOEpatents

    Atac, Muzaffer

    1989-01-01

    A wire chamber or proportional counter device, such as Geiger-Mueller tube or drift chamber, improved with a gas mixture providing a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor.

  8. High-speed laser anemometer system for intrarotor flow mapping in turbomachinery

    NASA Technical Reports Server (NTRS)

    Powell, J. A.; Strazisar, A. J.; Seasholtz, R. G.

    1982-01-01

    A fringe-type laser anemometer with innovative features is described. The innovative features include: (1) rapid, efficient data acquisition processes, (2) detailed graphic display of data being accumulated, and (3) input laser-beam positioning that allows greater optical access to the intrarotor region. Results are presented that demonstrate the anemometer's capability in flow mapping within a transonic axial-flow compressor rotor.

  9. Flow visualization efforts and pilot measurements with a laser-Doppler anemometer in backscatter mode

    NASA Technical Reports Server (NTRS)

    Buetefisch, K. A.

    1982-01-01

    Activities involving the use flow visualization and laser anemometers are reviewed. In particular, turbulent pipe flow measurements and local velocity determination in a 3 X 3 sq meter wind tunnel are discussed. The calibration of laser anemometer systems using a rotating disk is also addressed.

  10. Wire Wise.

    ERIC Educational Resources Information Center

    Swanquist, Barry

    1998-01-01

    Discusses how today's technology is encouraging schools to invest in furnishings that are adaptable to computer use and telecommunications access. Explores issues concerning modularity, wiring management, ergonomics, durability, price, and aesthetics. (GR)

  11. Particle size and velocity measurement in flames by laser anemometer

    NASA Technical Reports Server (NTRS)

    Chigier, N. A.; Ungut, A.; Yule, A. J.

    1979-01-01

    Simultaneous droplet size and velocity measurements by a particle counting Laser Doppler Anemometer (LDA) in kerosene fuel sprays under burning and non-burning conditions are presented. Particle sizes are derived from pulse height analysis of the mean LDA signals and velocities are simultaneously determined by measuring Doppler shift frequencies. The measurements show that droplet velocity is a function of droplet diameter for burning and non-burning conditions, and spatially averaged size distributions are derived from velocity data. A comparison of results obtained under burning and non-burning conditions show changes in size distribution due to preferential vaporization of small droplets, acceleration due to thermal expansion of gases, and corresponding changes in droplet momentum.

  12. Filter induced errors in laser anemometer measurements using counter processors

    NASA Technical Reports Server (NTRS)

    Oberle, L. G.; Seasholtz, R. G.

    1985-01-01

    Simulations of laser Doppler anemometer (LDA) systems have focused primarily on noise studies or biasing errors. Another possible source of error is the choice of filter types and filter cutoff frequencies. Before it is applied to the counter portion of the signal processor, a Doppler burst is filtered to remove the pedestal and to reduce noise in the frequency bands outside the region in which the signal occurs. Filtering, however, introduces errors into the measurement of the frequency of the input signal which leads to inaccurate results. Errors caused by signal filtering in an LDA counter-processor data acquisition system are evaluated and filters for a specific application which will reduce these errors are chosen.

  13. Rotary slanted single wire CTA - a useful tool for 3D flows investigations

    NASA Astrophysics Data System (ADS)

    Jonáš, P.

    2013-04-01

    The procedure is described of experimental investigation of a statistically stationary generally nonisothermal 3D flow by means of a constant temperature anemometer (CTA) using single slanted heated wire, rotary round the fixed axis. The principle of this procedure is quite clear. The change of the heated wire temperature modifies ratio of CTA sensitivities to temperature and velocity fluctuations. Turning the heated wire through a proper angle changes the sensitivity to components of the instantaneous velocity vector. Some recommendations are presented based on long time experiences, e.g. on the choice of probe, on the probe calibration, to the measurement organization and to the evaluation of results.

  14. Low-Inductance Wiring For Parallel Switching Transistors

    NASA Technical Reports Server (NTRS)

    Veatch, M. S.; Landis, D. M.

    1990-01-01

    Simple configuration for wiring of multiple parallel-connected switching transistors minimizes stray wiring inductance while providing for use of balancing transformers, which equalize currents in transistors. Currents balanced on twisted pairs of wires. Because twisted pairs carry both "hot-side" and return currents, this configuration has relatively low inductance.

  15. Hot film anemometry. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Habercom, G. E., Jr.

    1980-08-01

    The principles of hot film anemometer operation are summarized; wind tunnel and laboratory tests are described; flow field dynamics are discussed involving turbulence, boundary layers, separation, shock waves, and stresses; mathematical models and analysis are presented; computer techniques are outlined; and a number of applications are given. This updated bibliography contains 58 citations, 3 of which are new entries to the previous edition.

  16. Method for fabricating thin californium-containing radioactive source wires

    DOEpatents

    Gross, Ian G; Pierce, Larry A

    2006-08-22

    A method for reducing the cross-sectional diameter of a radioactive californium-containing cermet wire while simultaneously improving the wire diameter to a more nearly circular cross section. A collet fixture is used to reduce the wire diameter by controlled pressurization pulses while simultaneously improving the wire cross-sectional diameter. The method is especially suitable for use in hot cells for the production of optimized cermet brachytherapy sources that contain large amounts of radioactive californium-252.

  17. Measurement of stratospheric turbulence by balloon-borne 'glow-discharge' anemometer

    NASA Astrophysics Data System (ADS)

    Yamanaka, M. D.; Hirosawa, H.; Matsuzaka, Y.; Yamagami, T.; Tanaka, H.

    1985-06-01

    Attention is given to the specifications of a novel balloon-borne ionic anemometer which uses the type of glow discharge studied by Sekiguchi et al. (1963) and Hirosawa et al. (1964) as an ion source for long duration observations. The data obtained by the anemometer during its first flight, in September 1983, shows inhomogeneous fine structures within a stratospheric turbulence layer. A cursory analysis of the data obtained implies systematic stratospheric turbulence structures.

  18. No Wires.

    ERIC Educational Resources Information Center

    DeLoughry, Thomas J.

    1995-01-01

    The University of California at Santa Cruz has completed a successful test of a wireless computer network that would enable students and professors to get on line from anywhere on campus. The network, linked by radio waves, could save millions of dollars in campus wiring costs and would better meet student and faculty information needs. (MSE)

  19. Parametric study of beam refraction problems across laser anemometer windows

    NASA Technical Reports Server (NTRS)

    Owen, A. K.

    1986-01-01

    The experimenter is often required to view flows through a window with a different index of refraction than either the medium being observed or the medium that the laser anemometer is immersed in. The refraction that occurs at the window surfaces may lead to undesirable changes in probe volume position or beam crossing angle and can lead to partial or complete beam uncrossing. This report describes the results of a parametric study of this problem using a ray tracing technique to predict these changes. The windows studied were a flat plate and a simple cyclinder. For the flat-plate study: (1) surface thickness, (2) beam crossing angle, (3) bisecting line - surface normal angle, and (4) incoming beam plane surface orientation were varied. For the cylindrical window additional parameters were also varied: (1) probe volume immersion, (2) probe volume off-radial position, and (3) probe volume position out of the R-theta plane of the lens. A number of empirical correlations were deduced to aid the interested reader in determining the movement, uncrossing, and change in crossing angle for a particular situation.

  20. Hot film wall shear instrumentation for compressible boundary layer transition research

    NASA Technical Reports Server (NTRS)

    Schneider, Steven P.

    1992-01-01

    Experimental and analytical studies of hot film wall shear instrumentation were performed. A new hot film anemometer was developed and tested. The anemometer performance was not quite as good as that of commercial anemometers, but the cost was much less and testing flexibility was improved. The main focus of the project was a parametric study of the effect of sensor size and substrate material on the performance of hot film surface sensors. Both electronic and shock-induced flow experiments were performed to determine the sensitivity and frequency response of the sensors. The results are presented in Michael Moen's M.S. thesis, which is appended. A condensed form of the results was also submitted for publication.

  1. Accuracy of Sonic Anemometers: Laminar Wind-Tunnel Calibrations Compared to Atmospheric In Situ Calibrations Against a Reference Instrument

    NASA Astrophysics Data System (ADS)

    Högström, Ulf; Smedman, Ann-Sofi

    Two Gill Solent Ultrasonic anemometers, models 1012R2 and 1210R3, weretested in field parallel measurements against a windvane based hot-film anemometerwith additional sensors for temperature and wet-bulb temperature, the MIUU (MIUU:Meteorology Institute, Uppsala University) instrument. This instrument was shown toretain its precision from laminar wind-tunnel tests when used in atmospheric turbulentflow. This contrasts strongly to the observed results for the two sonic anemometers,which were first calibrated in laminar wind-tunnel flow. Individual three-dimensionalcalibration matrices were constructed, and were shown to reduce the remaining calibration uncertainty for the wind speed to 0.4-0.8% for all azimuths and for angles of attack within ±40°. In the field intercomparison tests of the sonics against the MIUU instrument, it was found that the precision not only of the mean wind speed but of all second-order moments studied (variances and covariances, with and without temperature) deteriorated by a factor of typically three to four. Most of the scatter appears to be random, but in the case of the wind speed, a clear dependence on wind direction is found as well. It is concluded that the correction for the effect of the vertical supporting rods of the R2 and R3 instruments, which gives nearly perfect agreement for laminar flow, does not work entirely satisfactory in the natural turbulent flow. This, in turn, is likely to be so because of high sensitivity of the wake behind the cylindrical supporting rods to the character of the approach flow.

  2. A computer controlled signal preprocessor for laser fringe anemometer applications

    NASA Technical Reports Server (NTRS)

    Oberle, Lawrence G.

    1987-01-01

    The operation of most commercially available laser fringe anemometer (LFA) counter-processors assumes that adjustments are made to the signal processing independent of the computer used for reducing the data acquired. Not only does the researcher desire a record of these parameters attached to the data acquired, but changes in flow conditions generally require that these settings be changed to improve data quality. Because of this limitation, on-line modification of the data acquisition parameters can be difficult and time consuming. A computer-controlled signal preprocessor has been developed which makes possible this optimization of the photomultiplier signal as a normal part of the data acquisition process. It allows computer control of the filter selection, signal gain, and photo-multiplier voltage. The raw signal from the photomultiplier tube is input to the preprocessor which, under the control of a digital computer, filters the signal and amplifies it to an acceptable level. The counter-processor used at Lewis Research Center generates the particle interarrival times, as well as the time-of-flight of the particle through the probe volume. The signal preprocessor allows computer control of the acquisition of these data.Through the preprocessor, the computer also can control the hand shaking signals for the interface between itself and the counter-processor. Finally, the signal preprocessor splits the pedestal from the signal before filtering, and monitors the photo-multiplier dc current, sends a signal proportional to this current to the computer through an analog to digital converter, and provides an alarm if the current exceeds a predefined maximum. Complete drawings and explanations are provided in the text as well as a sample interface program for use with the data acquisition software.

  3. Precision wire feeder for small diameter wire

    DOEpatents

    Brandon, Eldon D.; Hooper, Frederick M.; Reichenbach, Marvin L.

    1992-01-01

    A device for feeding small diameter wire having a diameter less than 0.04 mm (16 mil) to a welding station includes a driving wheel for controllably applying a non-deforming driving force to the wire to move the free end of the wire towards the welding station; and a tension device such as a torque motor for constantly applying a reverse force to the wire in opposition to the driving force to keep the wire taut.

  4. Precision wire feeder for small diameter wire

    DOEpatents

    Brandon, E.D.; Hooper, F.M.; Reichenbach, M.L.

    1992-08-11

    A device for feeding small diameter wire having a diameter less than 0.04 mm (16 mil) to a welding station includes a driving wheel for controllably applying a non-deforming driving force to the wire to move the free end of the wire towards the welding station; and a tension device such as a torque motor for constantly applying a reverse force to the wire in opposition to the driving force to keep the wire taut. 1 figure.

  5. The performance of sonic anemometers under foggy conditions - An intercomparision above a Taiwanese mountainous cloud forest

    NASA Astrophysics Data System (ADS)

    El-Madany, T.; Griessbaum, F.; Maneke, F.; Chu, H.-S.; Wu, C.-C.; Chang, S. C.; Hsia, Y.-J.; Juang, J.-Y.; Klemm, O.

    2010-07-01

    Foggy conditions are a toughness test for anemometers because the transceivers are continuously influenced by the deposition of fog-droplets. During a period of nearly four weeks three sonic anemometers where tested for their performance under foggy conditions. The anemometers were set up on a 24 meter high flux tower in a 14 meter high Chamaecyparis obtusa var. Formosana forest. The test anemometers were a Gill R3-50, a Young 81000V, and a Campbell CSAT3 (equipped with ‘dripping noses’). All anemometers were set up at one level on the highest platform of the tower. The performance was evaluated on the basis of 10 Hz data. The test site is located in the northwest of Taiwan at about 1650 m above sea level. This location is influenced by a steady diurnal wind system of valley winds during daytime and mountain winds during nighttime. The valley winds transport air masses from the coast up to the mountain where they cool down and fog development occurs. Due to this effect the site is highly frequented with fog. Results of this intercomparison will be presented.

  6. Effects of precipitation on sonic anemometer measurements of turbulent fluxes in the atmospheric surface layer

    NASA Astrophysics Data System (ADS)

    Zhang, Rongwang; Huang, Jian; Wang, Xin; Zhang, Jun A.; Huang, Fei

    2016-06-01

    Effects caused by precipitation on the measurements of three-dimensional sonic anemometer are analyzed based on a field observational experiment conducted in Maoming, Guangdong Province, China. Obvious fluctuations induced by precipitation are observed for the outputs of sonic anemometer-derived temperature and wind velocity components. A technique of turbulence spectra and cospectra normalized in the framework of similarity theory is utilized to validate the measured variables and calculated fluxes. It is found that the sensitivity of sonic anemometer-derived temperature to precipitation is significant, compared with that of the wind velocity components. The spectra of wind velocity and cospectra of momentum flux resemble the standard universal shape with the slopes of the spectra and cospectra at the inertial subrange, following the -2/3 and -4/3 power law, respectively, even under the condition of heavy rain. Contaminated by precipitation, however, the spectra of temperature and cospectra of sensible heat flux do not exhibit a universal shape and have obvious frequency loss at the inertial subrange. From the physical structure and working principle of sonic anemometer, a possible explanation is proposed to describe this difference, which is found to be related to the variations of precipitation particles. Corrections for errors of sonic anemometer-derived temperature under precipitation is needed, which is still under exploration.

  7. Highly resolved measurements of atmospheric turbulence with the new 2d-Atmospheric Laser Cantilever Anemometer

    NASA Astrophysics Data System (ADS)

    Jeromin, A.; Schaffarczyk, A. P.; Puczylowski, J.; Peinke, J.; Hölling, M.

    2014-12-01

    For the investigation of atmospheric turbulent flows on small scales a new anemometer was developed, the so-called 2d-Atmospheric Laser Cantilever Anemometer (2d-ALCA). It performs highly resolved measurements with a spatial resolution in millimeter range and temporal resolution in kHz range, thus detecting very small turbulent structures. The anemometer is a redesign of the successfully operating 2d-LCA for laboratory application. The new device was designed to withstand hostile operating environments (rain and saline, humid air). In February 2012, the 2d-ALCA was used for the first time in a test field. The device was mounted in about 53 m above ground level on a lattice tower near the German North Sea coast. Wind speed was measured by the 2d-ALCA at 10 kHz sampling rate and by cup anemometers at 1 Hz. The instantaneous wind speed ranged from 8 m/s to 19 m/s at an average turbulence level of about 7 %. Wind field characteristics were analyzed based on cup anemometer as well as 2d-ALCA. The combination of both devices allowed the study of atmospheric turbulence over several magnitudes in turbulent scales.

  8. Fiber optic anemometer based on metal infiltrated microstructured optical fiber inscribed with Bragg grating

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Gao, Shaorui; Liu, Zhengyong; Zhang, A. Ping; Shen, Yonghang; Tam, Hwayaw

    2015-09-01

    An all-fiber optical anemometer with high light-heat conversion efficiency by using an in-house microstructured optical fiber Bragg grating (MOFBG) is presented. Low-molten-temperature BiSnIn alloy was successfully infiltrated into 11- cm length of a six-hole microstructured optical fiber which was inscribed with a fibre Bragg grating (FBG) centered at ~848 nm. Light launched into the MOFBG was strongly absorbed by the metal to generate heat, while the FBG was utilized to monitor temperature change due to surrounding wind speed. The sensitivity of the laser-heated MOFBG anemometer was measured to be ~0.1 nm/(m/s) for wind speed ranged from 0.5 m/s to 2 m/s. The efficiency of the anemometer, defined as effective sensitivity per pump power, is 8.7 nm/(m/s*W).

  9. Direct measurement of the spectral transfer function of a laser based anemometer.

    PubMed

    Angelou, Nikolas; Mann, Jakob; Sjöholm, Mikael; Courtney, Michael

    2012-03-01

    The effect of a continuous-wave (cw) laser based anemometer's probe volume on the measurement of wind turbulence is studied in this paper. Wind speed time series acquired by both a remote sensing cw laser anemometer, whose line-of-sight was aligned with the wind direction, and by a reference sensor (sonic anemometer) located in the same direction, were used. The spectral transfer function, which describes the attenuation of the power spectral density of the wind speed turbulence, was calculated and found to be in good agreement with the theoretical exponential function, which is based on the properties of the probe volume of a focused Gaussian laser beam. Parameters such as fluctuations of the wind direction, as well as the overestimation of the laser Doppler spectrum threshold, were found to affect the calculation of the spectral transfer function by introducing high frequency noise.

  10. The K-Gill - A twin propeller-vane anemometer for measurements of atmospheric turbulence

    NASA Technical Reports Server (NTRS)

    Atakturk, Serhad S.; Katsaros, Kristina B.

    1989-01-01

    A twin propeller-vane anemometer developed at the University of British Columbia was successfully used for unattended measurement of atmospheric turbulence over extended periods of time during moderate to high winds in the presence of sea spray. In this paper, a new design in twin propeller-vane anemometers is introduced. The instrument consists of two Gill anemometers mounted on a vane. The propeller shafts, one pointing up and the other pointing down, make an angle of 45 deg with the horizontal (hence, the name K-Gill). In addition to the desirable characteristics of the earlier design the K-Gill has symmetry, so that updraft and downdraft winds are measured with equal sensitivity. An algorithm for obtaining the vertical and downstream horizontal components of the wind velocity is described. Various sources of error and their magnitudes are discussed.

  11. Direct measurement of the spectral transfer function of a laser based anemometer.

    PubMed

    Angelou, Nikolas; Mann, Jakob; Sjöholm, Mikael; Courtney, Michael

    2012-03-01

    The effect of a continuous-wave (cw) laser based anemometer's probe volume on the measurement of wind turbulence is studied in this paper. Wind speed time series acquired by both a remote sensing cw laser anemometer, whose line-of-sight was aligned with the wind direction, and by a reference sensor (sonic anemometer) located in the same direction, were used. The spectral transfer function, which describes the attenuation of the power spectral density of the wind speed turbulence, was calculated and found to be in good agreement with the theoretical exponential function, which is based on the properties of the probe volume of a focused Gaussian laser beam. Parameters such as fluctuations of the wind direction, as well as the overestimation of the laser Doppler spectrum threshold, were found to affect the calculation of the spectral transfer function by introducing high frequency noise. PMID:22462910

  12. A Bayesian model to estimate the true 3-D shadowing correction in sonic anemometers

    NASA Astrophysics Data System (ADS)

    Frank, J. M.; Massman, W. J.; Ewers, B. E.

    2015-12-01

    Sonic anemometers are the principal instruments used in micrometeorological studies of turbulence and ecosystem fluxes. Recent studies have shown the most common designs underestimate vertical wind measurements because they lack a correction for transducer and structural shadowing; there is no consensus describing a true correction. We introduce a novel Bayesian analysis with the potential to resolve the three-dimensional (3-D) correction by optimizing differences between anemometers mounted simultaneously vertical and horizontal. The analysis creates a geodesic grid around the sonic anemometer, defines a state variable for the 3-D correction at each point, and assigns each a prior distribution based on literature with ±10% uncertainty. We use the Markov chain Monte Carlo (MCMC) method to update and apply the 3-D correction to a dataset of 20-Hz sonic anemometer measurements, calculate five-minute standard deviations of the Cartesian wind components, and compare these statistics between vertical and horizontal anemometers. We present preliminary analysis of the CSAT3 anemometer using 642 grid points (±4.5° resolution) from 423 five-minute periods (8,964,000 samples) collected during field experiments in 2011 and 2013. The 20-Hz data was not equally distributed around the grid; half of the samples occurred in just 8% of the grid points. For populous grid points (weighted by the abundance of samples) the average correction increased from prior to posterior (+5.4±10.0% to +9.1±9.5%) while for desolate grid points (weighted by the sparseness of samples) there was minimal change (+6.4±10.0% versus +6.6±9.8%), demonstrating that with a sufficient number of samples the model can determine the true correction is ~67% higher than proposed in recent literature. Future adaptions will increase the grid resolution and sample size to reduce the uncertainty in the posterior distributions and more precisely quantify the 3-D correction.

  13. Feasibility study of transit photon correlation anemometer for Ames Research Center unitary wind tunnel plan

    NASA Technical Reports Server (NTRS)

    Mayo, W. T., Jr.; Smart, A. E.

    1979-01-01

    A laser transit anemometer measured a two-dimensional vector velocity, using the transit time of scattering particles between two focused and parallel laser beams. The objectives were: (1) the determination of the concentration levels and light scattering efficiencies of naturally occurring, submicron particles in the NASA/Ames unitary wind tunnel and (2) the evaluation based on these measured data of a laser transit anemometer with digital correlation processing for nonintrusive velocity measurement in this facility. The evaluation criteria were the speeds at which point velocity measurements could be realized with this technique (as determined from computer simulations) for given accuracy requirements.

  14. Motion-Corrected 3D Sonic Anemometer for Tethersondes and Other Moving Platforms

    NASA Technical Reports Server (NTRS)

    Bognar, John

    2012-01-01

    To date, it has not been possible to apply 3D sonic anemometers on tethersondes or similar atmospheric research platforms due to the motion of the supporting platform. A tethersonde module including both a 3D sonic anemometer and associated motion correction sensors has been developed, enabling motion-corrected 3D winds to be measured from a moving platform such as a tethersonde. Blimps and other similar lifting systems are used to support tethersondes meteorological devices that fly on the tether of a blimp or similar platform. To date, tethersondes have been limited to making basic meteorological measurements (pressure, temperature, humidity, and wind speed and direction). The motion of the tethersonde has precluded the addition of 3D sonic anemometers, which can be used for high-speed flux measurements, thereby limiting what has been achieved to date with tethersondes. The tethersonde modules fly on a tether that can be constantly moving and swaying. This would introduce enormous error into the output of an uncorrected 3D sonic anemometer. The motion correction that is required must be implemented in a low-weight, low-cost manner to be suitable for this application. Until now, flux measurements using 3D sonic anemometers could only be made if the 3D sonic anemometer was located on a rigid, fixed platform such as a tower. This limited the areas in which they could be set up and used. The purpose of the innovation was to enable precise 3D wind and flux measurements to be made using tether - sondes. In brief, a 3D accelerometer and a 3D gyroscope were added to a tethersonde module along with a 3D sonic anemometer. This combination allowed for the necessary package motions to be measured, which were then mathematically combined with the measured winds to yield motion-corrected 3D winds. At the time of this reporting, no tethersonde has been able to make any wind measurement other than a basic wind speed and direction measurement. The addition of a 3D sonic

  15. A laser fluorescence anemometer system for the Langley 16- by 24-inch water tunnel

    NASA Technical Reports Server (NTRS)

    Owen, F. K.; Orngard, Gary M.; Neuhart, Dan H.

    1991-01-01

    A laser fluorescence anemometer which comprises a three-component laser Doppler velocimeter system with a fourth channel to measure fluorescent dye concentration has been installed in the NASA Langley 16- by 24-in water tunnel. The system includes custom designed optics, data acquisition, and traverse control instruments and a custom software package. Feasibility studies demonstrated how water tunnels can be used in conjunction with advanced optical techniques to provide nonintrusive detailed flow field measurements of complex fluid flows with a minimum of expense. The measurements show that the laser fluorescence anemometer can provide new insight into the structure, entrainment, control and of mixing vortical and shear layer flows.

  16. Mathematical analysis of the effect of rotor geometry on cup anemometer response.

    PubMed

    Sanz-Andrés, Ángel; Pindado, Santiago; Sorribes-Palmer, Félix

    2014-01-01

    The calibration coefficients of two commercial anemometers equipped with different rotors were studied. The rotor cups had the same conical shape, while the size and distance to the rotation axis varied. The analysis was based on the 2-cup positions analytical model, derived using perturbation methods to include second-order effects such as pressure distribution along the rotating cups and friction. The comparison with the experimental data indicates a nonuniform distribution of aerodynamic forces on the rotating cups, with higher forces closer to the rotating axis. The 2-cup analytical model is proven to be accurate enough to study the effect of complex forces on cup anemometer performance. PMID:25110735

  17. Mathematical Analysis of the Effect of Rotor Geometry on Cup Anemometer Response

    PubMed Central

    Sanz-Andrés, Ángel; Sorribes-Palmer, Félix

    2014-01-01

    The calibration coefficients of two commercial anemometers equipped with different rotors were studied. The rotor cups had the same conical shape, while the size and distance to the rotation axis varied. The analysis was based on the 2-cup positions analytical model, derived using perturbation methods to include second-order effects such as pressure distribution along the rotating cups and friction. The comparison with the experimental data indicates a nonuniform distribution of aerodynamic forces on the rotating cups, with higher forces closer to the rotating axis. The 2-cup analytical model is proven to be accurate enough to study the effect of complex forces on cup anemometer performance. PMID:25110735

  18. Mathematical analysis of the effect of rotor geometry on cup anemometer response.

    PubMed

    Sanz-Andrés, Ángel; Pindado, Santiago; Sorribes-Palmer, Félix

    2014-01-01

    The calibration coefficients of two commercial anemometers equipped with different rotors were studied. The rotor cups had the same conical shape, while the size and distance to the rotation axis varied. The analysis was based on the 2-cup positions analytical model, derived using perturbation methods to include second-order effects such as pressure distribution along the rotating cups and friction. The comparison with the experimental data indicates a nonuniform distribution of aerodynamic forces on the rotating cups, with higher forces closer to the rotating axis. The 2-cup analytical model is proven to be accurate enough to study the effect of complex forces on cup anemometer performance.

  19. Four-Spot Time-Of-Flight Laser Anemometer For Turbomachinery

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.; Skoch, Gary J.

    1995-01-01

    Two-color, four-spot time-of-flight laser anemometer designed for measuring flow velocity within narrow confines of small centrifugal compressor. Apparatus well suited for measuring fast (typical speeds 160 to 700 m/s), highly turbulent gas flows in turbomachinery. Other potential applications include measurement of gas flows in pipelines and in flows from explosions.

  20. MEASUREMENT OF MOTION CORRECTED WIND VELOCITY USING AN AEROSTAT LOFTED SONIC ANEMOMETER

    EPA Science Inventory

    An aerostat-lofted, sonic anemometer was used to determine instantaneous 3 dimensional wind velocities at altitudes relevant to fire plume dispersion modeling. An integrated GPS, inertial measurement unit, and attitude heading and reference system corrected the wind data for th...

  1. Windows: Life after Wire.

    ERIC Educational Resources Information Center

    Razwick, Jerry

    2003-01-01

    Although wired glass is extremely common in school buildings, the International Building Code adopted new standards that eliminate the use of traditional wired glass in K-12 schools, daycare centers, and athletic facilities. Wired glass breaks easily, and the wires can cause significant injuries by forming dangerous snags when the glass breaks.…

  2. Final report on EURAMET project No. 827: LDA-based intercomparison of anemometers

    NASA Astrophysics Data System (ADS)

    Müller, Harald

    2013-01-01

    A regional air speed comparison between six EURAMET laboratories used an ultrasonic anemometer and a laser Doppler anemometer (LDA) at air speeds between 0.2 m s-1 and 40 m s-1. Based on periodic calibrations at the pilot laboratory (PTB), the uncertainty contributed to the comparison by the LDA was 0.2% and the uncertainty contributed by the ultrasonic anemometer depended on the air speed and varied between 2.95% and 0.11%. The degrees of equivalence between the participants were notably better for the laser Doppler anemometer data than for the ultrasonic anemometer data. For example, using the 95% chi-squared consistency check, 16 of the original 59 participant data points were removed as discrepant from the ultrasonic data set, but only one point was discrepant in the LDA data. A possible explanation is that the LDA is non-intrusive and therefore does not alter the velocity field in the wind tunnel whereas the ultrasonic device does produce blockage effects. The results of this comparison (and prior EURAMET and CIPM comparisons) indicate a need for more attention to blockage effects during air speed calibrations and their effect on air speed uncertainty statements. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by EURAMET, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  3. Wire breakage in SLC wire profile monitors

    SciTech Connect

    Field, C.; McCormick, D.; Raimondi, P.; Ross, M.

    1998-12-10

    Wire-scanning beam profile monitors are used at the Stanford Linear Collider (SLC) for emittance preservation control and beam optics optimization. Twenty such scanners have proven most useful for this purpose and have performed a total of 1.5 million scans in the 4 to 6 years since their installation. Most of the essential scanners are equipped with 20 to 40 {mu}m tungsten wires. SLC bunch intensities and sizes often exceed 2x10{sup 7}particles/{mu}m{sup 2} (3C/m{sup 2}). We believe that this has caused a number of tungsten wire failures that appear at the ends of the wire, near the wire support points, after a few hundred scans are accumulated. Carbon fibers, also widely used at SLAC (1), have been substituted in several scanners and have performed well. In this paper, we present theories for the wire failure mechanism and techniques learned in reducing the failures.

  4. Wire breakage in SLC wire profile monitors

    SciTech Connect

    Field, C.; McCormick, D.; Raimondi, P.; Ross, M.

    1998-05-01

    Wire scanning beam profile monitors are used at the Stanford Linear Collider (SLC) for emittance preservation control and beam optics optimization. Twenty such scanners have proven most useful for this purpose and have performed a total of 1.5 million scans in the 4 to 6 years since their installation. Most of the essential scanners are equipped with 20 to 40 {micro}m tungsten wires. SLC bunch intensities and sizes often exceed 2 x 10{sup 7} particles/{micro}m{sup 2} (3C/m{sup 2}). The authors believe that this has caused a number of tungsten wire failures that appear at the ends of the wire, near the wire support points, after a few hundred scans are accumulated. Carbon fibers, also widely used at SLAC, have been substituted in several scanners and have performed well. In this paper, the authors present theories for the wire failure mechanism and techniques learned in reducing the failures.

  5. Concealed wire tracing apparatus

    DOEpatents

    Kronberg, James W.

    1994-01-01

    An apparatus and method that combines a signal generator and a passive signal receiver to detect and record the path of partially or completely concealed electrical wiring without disturbing the concealing surface. The signal generator applies a series of electrical pulses to the selected wiring of interest. The applied pulses create a magnetic field about the wiring that can be detected by a coil contained within the signal receiver. An audible output connected to the receiver and driven by the coil reflects the receivers position with respect to the wiring. The receivers audible signal is strongest when the receiver is directly above the wiring and the long axis of the receivers coil is parallel to the wiring. A marking means is mounted on the receiver to mark the location of the wiring as the receiver is directed over the wiring's concealing surface. Numerous marks made on various locations of the concealing surface will trace the path of the wiring of interest.

  6. Silicon Carbide High Temperature Anemometer and Method for Assembling the Same

    NASA Technical Reports Server (NTRS)

    Okojie, Robert S. (Inventor); Fralick, Gustave C. (Inventor); Saad, George J. (Inventor)

    2003-01-01

    A high temperature anemometer includes a pair of substrates. One of the substrates has a plurality of electrodes on a facing surface, while the other of the substrates has a sensor cavity on a facing surface. A sensor is received in the sensor cavity, wherein the sensor has a plurality of bondpads, and wherein the bond pads contact the plurality of electrodes when the facing surfaces are mated with one another. The anemometer further includes a plurality of plug-in pins, wherein the substrate with the cavity has a plurality of trenches with each one receiving a plurality of plug-in pins. The plurality of plug-in pins contact the plurality of electrodes when the substrates are mated with one another. The sensor cavity is at an end of one of the substrates such that the sensor partially extends from the substrate. The sensor and the substrates are preferably made of silicon carbide.

  7. A 3D micro-laser anemometer for boundary layer studies

    NASA Astrophysics Data System (ADS)

    Ahmed, N. A.; Elder, R. L.; Forster, C. P.; Jones, J. D. C.

    A miniature sized instrument called the 'three-dimensional microlaser Doppler anemometer' has been developed at Cranfield Institute of Technology, primarily intended for boundary layer measurements in centrifugal compressors but retaining all the features of other conventional laser Doppler anemometers. It has a high spatial resolution (80 micron cube) and uses oblique back-scatter to enable velocity measurements in all three dimensions. An optical head is remotely connected via fiber optic cables to the laser, photomultiplier tubes and signal processing equipment. In this paper, the design objectives, design philosophy and commissioning of the instrument are described. The mathematics of these dimensional measurements and the results of a test to demonstrate the instrument are also presented.

  8. Comparison of surface wind stress measurements - Airborne radar scatterometer versus sonic anemometer

    NASA Technical Reports Server (NTRS)

    Brucks, J. T.; Leming, T. D.; Jones, W. L.

    1980-01-01

    Sea surface wind stress measurements recorded by a sonic anemometer are correlated with airborne scatterometer measurements of ocean roughness (cross section of radar backscatter) to establish the accuracy of remotely sensed data and assist in the definition of geophysical algorithms for the scatterometer sensor aboard Seasat A. Results of this investigation are as follows: Comparison of scatterometer and sonic anemometer wind stress measurements are good for the majority of cases; however, a tendency exists for scatterometer wind stress to be somewhat high for higher wind conditions experienced in this experiment (6-9 m/s). The scatterometer wind speed algorithm tends to overcompute the higher wind speeds by approximately 0.5 m/s. This is a direct result of the scatterometer overestimate of wind stress from which wind speeds are derived. Algorithmic derivations of wind speed and direction are, in most comparisons, within accuracies defined by Seasat A scatterometer sensor specifications.

  9. Optimization of fringe-type laser anemometers for turbine engine component testing

    NASA Technical Reports Server (NTRS)

    Seasholtz, R. G.; Oberle, L. G.; Weikle, D. H.

    1984-01-01

    The fringe type laser anemometer is analyzed using the Cramer-Rao bound for the variance of the estimate of the Doppler frequency as a figure of merit. Mie scattering theory is used to calculate the Doppler signal wherein both the amplitude and phase of the scattered light are taken into account. The noise from wall scatter is calculated using the wall bidirectional reflectivity and the irradiance of the incident beams. A procedure is described to determine the optimum aperture mask for the probe volume located a given distance from a wall. The expected performance of counter type processors is also discussed in relation to the Cramer-Rao bound. Numerical examples are presented for a coaxial backscatter anemometer.

  10. Pointwise and scanning laser anemometer measurements in steady and unsteady separated turbulent boundary layers

    NASA Technical Reports Server (NTRS)

    Simpson, R. L.; Chehroudi, B.; Shivaprasad, B. G.

    1982-01-01

    The physical features of steady and unsteady freestream separating turbulent boundary layers that have been determined by pointwise laser anemometer measurements are outlined. It is seen that the large-scale structures control the outer region's backflow behavior. Near the wall, the mean backflow velocity profile for both the steady and unsteady cases is found to scale on the maximum negative mean velocity and its distance from the wall. A description is given of a scanning laser anemometer that produces nearly instantaneous velocity profiles for examing the temporal features of these large-scale structures. Also described is a 'zero-wake' seeder that supplies particles to the outer shear layer and freestream flow with a minimal disturbance.

  11. Rotationally sampled wind characteristics for several rotor sizes using laser anemometer measurements

    SciTech Connect

    Connell, J.R.; Morris, V.R.

    1989-02-01

    The concept of measuring the wind velocity rotationally around crosswind circles using a circle-scanning Doppler laser anemometer is investigated to determine the technique's suitability as an effective, simple, economical, and nonintrusive method for estimation turbulence at a wind turbine rotor. Estimates of wind features obtained using the lidar technique are compared to actual wind measurements obtained using a vertical plane array of anemometers, and to other estimates generated using a single-tower technique. Although the lack of a common data set precludes a firm conclusion regarding the lidar method's accuracy, it appears that the rotationally scanning lidar has the potential of becoming an excellent tool for measuring turbulent wind around the disk of rotation of a turbine blade. 11 refs., 21 figs., 2 tabs.

  12. Model studies of blood flow in basilar artery with 3D laser Doppler anemometer

    NASA Astrophysics Data System (ADS)

    Frolov, S. V.; Sindeev, S. V.; Liepsch, D.; Balasso, A.; Proskurin, S. G.; Potlov, A. Y.

    2015-03-01

    It is proposed an integrated approach to the study of basilar artery blood flow using 3D laser Doppler anemometer for identifying the causes of the formation and development of cerebral aneurysms. Feature of the work is the combined usage of both mathematical modeling and experimental methods. Described the experimental setup and the method of measurement of basilar artery blood flow, carried out in an interdisciplinary laboratory of Hospital Rechts der Isar of Technical University of Munich. The experimental setup used to simulate the blood flow in the basilar artery and to measure blood flow characteristics using 3D laser Doppler anemometer (3D LDA). Described a method of numerical studies carried out in Tambov State Technical University and the Bakoulev Center for Cardiovascular Surgery. Proposed an approach for sharing experimental and numerical methods of research to identify the causes of the basilar artery aneurysms.

  13. Laser transit anemometer measurements of a JANNAF nozzle base velocity flow field

    NASA Technical Reports Server (NTRS)

    Hunter, William W., Jr.; Russ, C. E., Jr.; Clemmons, J. I., Jr.

    1990-01-01

    Velocity flow fields of a nozzle jet exhausting into a supersonic flow were surveyed. The measurements were obtained with a laser transit anemometer (LTA) system in the time domain with a correlation instrument. The LTA data is transformed into the velocity domain to remove the error that occurs when the data is analyzed in the time domain. The final data is shown in velocity vector plots for positions upstream, downstream, and in the exhaust plane of the jet nozzle.

  14. Wind tunnel test of Teledyne Geotech model 1564B cup anemometer

    SciTech Connect

    Parker, M.J.; Addis, R.P.

    1991-04-04

    The Department of Energy (DOE) Environment, Safety and Health Compliance Assessment (Tiger Team) of the Savannah River Site (SRS) questioned the method by which wind speed sensors (cup anemometers) are calibrated by the Environmental Technology Section (ETS). The Tiger Team member was concerned that calibration data was generated by running the wind tunnel to only 26 miles per hour (mph) when speeds exceeding 50 mph are readily obtainable. A wind tunnel experiment was conducted and confirmed the validity of the practice. Wind speeds common to SRS (6 mph) were predicted more accurately by 0--25 mph regression equations than 0--50 mph regression equations. Higher wind speeds were slightly overpredicted by the 0--25 mph regression equations when compared to 0--50 mph regression equations. However, the greater benefit of more accurate lower wind speed predictions accuracy outweight the benefit of slightly better high (extreme) wind speed predictions. Therefore, it is concluded that 0--25 mph regression equations should continue to be utilized by ETS at SRS. During the Department of Energy Tiger Team audit, concerns were raised about the calibration of SRS cup anemometers. Wind speed is measured by ETS with Teledyne Geotech model 1564B cup anemometers, which are calibrated in the ETS wind tunnel. Linear regression lines are fitted to data points of tunnel speed versus anemometer output voltages up to 25 mph. The regression coefficients are then implemented into the data acquisition computer software when an instrument is installed in the field. The concern raised was that since the wind tunnel at SRS is able to generate a maximum wind speed higher than 25 mph, errors may be introduced in not using the full range of the wind tunnel.

  15. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1998-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: 3.7 amps per wire, bundle of 15 or more wires, 70 C environment, and vacuum of 10(exp -5) torr or less. To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  16. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1999-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 degree C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: (1) 3.7 amps per wire (2) bundle of 15 or more wires (3) 70 C environment (4) vacuum of 10(exp -5) torr or less To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  17. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1998-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: (1) 3.7 amps per wire; (2) bundle of 15 or more wires; (3) 70 C environment: and (4) vacuum of 10(exp -5) torr or less. To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  18. Fiber optic anemometer based on silicon Fabry-Pérot interferometer

    NASA Astrophysics Data System (ADS)

    Liu, Guigen; Hou, Weilin; Qiao, Wei; Han, Ming

    2015-05-01

    Flowmeters have been finding vast applications in all kinds of industrial processes, such as process control, food quality surveillance, wind turbines, environment monitoring, etc. In this paper, we propose a new anemometer which consists of a Fabry-Pérot interferometer (FPI) implemented using a thin silicon mounted on the tip of an optical fiber. The anemometer takes advantage of the superior thermal and optical properties of silicon. Silicon is transparent to infrared wavelength, while it absorbs visible light. Thus, the silicon FPI can be heated by a beam injected from a red diode laser while the infrared signals go through it without any interference from the heating light. The heat loss from the silicon film will increase when the sensor is placed in stronger flow (wind), which induces a decrease in the optical path of the silicon FPI, which lead to blueshifts the output spectrum. A higher wind speed corresponds to a larger wavelength shift. By tuning the heating power, the response range and sensitivity of the anemometer is changed. Experimental results demonstrate that a wavelength shift -0.574 nm was observed for a wind speed of 4 m/s. Better sensitivity is to be expected when stronger heating applied. The proposed sensor also features simple structure, low cost and fast response.

  19. Wire harness twisting aid

    NASA Technical Reports Server (NTRS)

    Casey, E. J.; Commadore, C. C.; Ingles, M. E.

    1980-01-01

    Long wire bundles twist into uniform spiral harnesses with help of simple apparatus. Wires pass through spacers and through hand-held tool with hole for each wire. Ends are attached to low speed bench motor. As motor turns, operator moves hand tool away forming smooth twists in wires between motor and tool. Technique produces harnesses that generate less radio-frequency interference than do irregularly twisted cables.

  20. EMF wire code research

    SciTech Connect

    Jones, T.

    1993-11-01

    This paper examines the results of previous wire code research to determines the relationship with childhood cancer, wire codes and electromagnetic fields. The paper suggests that, in the original Savitz study, biases toward producing a false positive association between high wire codes and childhood cancer were created by the selection procedure.

  1. Laser Wire Stripper

    NASA Technical Reports Server (NTRS)

    1983-01-01

    NASA-developed space shuttle technology is used in a laser wire stripper designed by Raytheon Company. Laser beams cut through insulation on a wire without damaging conductive metal, because laser radiation that melts plastic insulation is reflected by the metal. The laser process is fast, clean, precise and repeatable. It eliminates quality control problems and the expense of rejected wiring.

  2. IMPROVED WIND AND TURBULENCE MEASUREMENTS USING A LOW-COST 3-D SONIC ANEMOMETER AT A LOW-WIND SITE

    SciTech Connect

    Bowen, B

    2007-05-11

    A year of data from sonic anemometer and mechanical wind sensors was analyzed and compared at a low-wind site. Results indicate that 15-minute average and peak 1-second wind speeds (u) from the sonic agree well with data derived from a co-located cup anemometer over a wide range of speeds. Wind direction data derived from the sonic also agree closely with those from a wind vane except for very low wind speeds. Values of standard deviation of longitudinal wind speed ({sigma}{sub u}) and wind direction fluctuations ({delta}{sub {theta}}) from the sonic and mechanical sensors agree well for times with u > 2 ms{sup -1} but show significant differences with lower u values. The most significant differences are associated with the standard deviation of vertical wind fluctuations ({sigma}{sub w}): the co-located vertical propeller anemometer yields values increasingly less than those measured by the sonic anemometer as u decreases from 2.5 approaching 0 ms{sup -1}. The combination of u over-estimation and under-estimation of {sigma}{sub w} from the mechanical sensors at low wind speeds causes considerable under-estimation of the standard deviation of vertical wind angle fluctuations ({sigma}{sub {phi}}), an indicator of vertical dispersion. Calculations of {sigma}{sub {phi}} from sonic anemometer measurements are typically 5{sup o} to 10{sup o} higher when the mechanical instruments indicate that {sigma}{sub {phi}} < 5{sup o} or so. The errors in both the propeller anemometer and cup anemometer, caused by their inability to respond to higher frequency (smaller scale) turbulent fluctuations, can therefore lead to large (factors of 2 to 10 or more) errors in the vertical dispersion during stable conditions with light winds.

  3. 30 CFR 77.1802 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 77.1802 Section 77.1802... Wires and Trolley Feeder Wires § 77.1802 Insulation of trolley wires, trolley feeder wires and...

  4. 30 CFR 77.1802 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 77.1802 Section 77.1802... Wires and Trolley Feeder Wires § 77.1802 Insulation of trolley wires, trolley feeder wires and...

  5. 30 CFR 77.1802 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 77.1802 Section 77.1802... Wires and Trolley Feeder Wires § 77.1802 Insulation of trolley wires, trolley feeder wires and...

  6. 30 CFR 75.1003 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 75.1003 Section 75.1003... Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires...

  7. 30 CFR 77.1802 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 77.1802 Section 77.1802... Wires and Trolley Feeder Wires § 77.1802 Insulation of trolley wires, trolley feeder wires and...

  8. 30 CFR 75.1003 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 75.1003 Section 75.1003... Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires...

  9. 30 CFR 75.1003 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 75.1003 Section 75.1003... Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires...

  10. 30 CFR 77.1802 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 77.1802 Section 77.1802... Wires and Trolley Feeder Wires § 77.1802 Insulation of trolley wires, trolley feeder wires and...

  11. 30 CFR 75.1003 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 75.1003 Section 75.1003... Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires...

  12. 30 CFR 75.1003 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 75.1003 Section 75.1003... Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires...

  13. Lingual straight wire method.

    PubMed

    Takemoto, Kyoto; Scuzzo, Giuseppe; Lombardo, L U C A; Takemoto, Y U I

    2009-12-01

    The mushroom arch-wire is mainly used in lingual orthodontic treatment but the complicated wire bending it requires affects both the treatment results and the time spent at the chair. The author proposes a new lingual straight wire method (LSW) in order to facilitate arch coordination and simplify the mechanics. The attention paid to the set-up model and bracket positioning and bonding plus the use of the new LSW method will also improve patient comfort.

  14. Sintered wire annode

    DOEpatents

    Falce, Louis R.; Ives, R. Lawrence

    2007-12-25

    A plurality of high atomic number wires are sintered together to form a porous rod that is parted into porous disks which will be used as x-ray targets. A thermally conductive material is introduced into the pores of the rod, and when a stream of electrons impinges on the sintered wire target and generates x-rays, the heat generated by the impinging x-rays is removed by the thermally conductive material interspersed in the pores of the wires.

  15. Mathematical Relationships Between Two Sets of Laser Anemometer Measurements for Resolving the Total Velocity Vector

    NASA Technical Reports Server (NTRS)

    Owen, Albert K.

    1993-01-01

    The mathematical relations between the measured velocity fields for the same compressor rotor flow field resolved by two fringe type laser anemometers at different observational locations are developed in this report. The relations allow the two sets of velocity measurements to be combined to produce a total velocity vector field for the compressor rotor. This report presents the derivation of the mathematical relations, beginning with the specification of the coordinate systems and the velocity projections in those coordinate systems. The vector projections are then transformed into a common coordinate system. The transformed vector coordinates are then combined to determine the total velocity vector. A numerical example showing the solution procedure is included.

  16. A 4-spot time-of-flight anemometer for small centrifugal compressor velocity measurements

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.; Skoch, Gary J.

    1992-01-01

    The application of laser anemometry techniques in turbomachinery facilities is a challenging dilemma requiring an anemometer system with special qualities. Here, we describe the use of a novel laser anemometry technique applied to a small 4.5 kg/s, 4:1 pressure ratio centrifugal compressor. Sample velocity profiles across the blade pitch are presented for a single location along the rotor. The results of the intra-blade passage velocity measurements will ultimately be used to verify CFD 3-D viscous code predictions.

  17. Turbulence fluxes and variances measured with a sonic anemometer mounted on a tethered balloon

    NASA Astrophysics Data System (ADS)

    Canut, Guylaine; Couvreux, Fleur; Lothon, Marie; Legain, Dominique; Piguet, Bruno; Lampert, Astrid; Maurel, William; Moulin, Eric

    2016-09-01

    This study presents the first deployment in field campaigns of a balloon-borne turbulence probe, developed with a sonic anemometer and an inertial motion sensor suspended below a tethered balloon. This system measures temperature and horizontal and vertical wind at high frequency and allows the estimation of heat and momentum fluxes as well as turbulent kinetic energy in the lower part of the boundary layer. The system was validated during three field experiments with different convective boundary-layer conditions, based on turbulent measurements from instrumented towers and aircraft.

  18. Concealed wire tracing apparatus

    DOEpatents

    Kronberg, J.W.

    1994-05-31

    An apparatus and method that combines a signal generator and a passive signal receiver to detect and record the path of partially or completely concealed electrical wiring without disturbing the concealing surface is disclosed. The signal generator applies a series of electrical pulses to the selected wiring of interest. The applied pulses create a magnetic field about the wiring that can be detected by a coil contained within the signal receiver. An audible output connected to the receiver and driven by the coil reflects the receivers position with respect to the wiring. The receivers audible signal is strongest when the receiver is directly above the wiring and the long axis of the receivers coil is parallel to the wiring. A marking means is mounted on the receiver to mark the location of the wiring as the receiver is directed over the wiring's concealing surface. Numerous marks made on various locations of the concealing surface will trace the path of the wiring of interest. 4 figs.

  19. Wire-inhomogeneity detector

    DOEpatents

    Gibson, G.H.; Smits, R.G.; Eberhard, P.H.

    1982-08-31

    A device for uncovering imperfections in electrical conducting wire, particularly superconducting wire, by detecting variations in eddy currents. Eddy currents effect the magnetic field in a gap of an inductor, contained in a modified commercial ferrite core, through which the wire being tested is passed. A small increase or decrease in the amount of conductive material, such as copper, in a fixed cross section of wire will unbalance a bridge used to measure the impedance of the inductor, tripping a detector and sounding an alarm.

  20. 1998 wire development workshop proceedings

    SciTech Connect

    1998-04-01

    This report consists of vugraphs of the presentations at the conference. The conference was divided into the following sessions: (1) First Generation Wire Development: Status and Issues; (2) First Generation Wire in Pre-Commercial Prototypes; (3) Second Generation Wire Development: Private Sector Progress and Issues; (4) Second Generation Wire Development: Federal Laboratories; and (5) Fundamental Research Issues for HTS Wire Development.

  1. VIEW SOUTHEASTBUILDING 4 NO. 1 WIRE MILL (1871) WIRE DRAWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW SOUTHEAST-BUILDING 4 NO. 1 WIRE MILL (1871) WIRE DRAWING MACHINE - John A. Roebling's Sons Company & American Steel & Wire Company, South Broad, Clark, Elmer, Mott & Hudson Streets, Trenton, Mercer County, NJ

  2. Anemometer calibrator

    NASA Technical Reports Server (NTRS)

    Bate, T.; Calkins, D. E.; Price, P.; Veikins, O.

    1971-01-01

    Calibrator generates accurate flow velocities over wide range of gas pressure, temperature, and composition. Both pressure and flow velocity can be maintained within 0.25 percent. Instrument is essentially closed loop hydraulic system containing positive displacement drive.

  3. Wire Array Photovoltaics

    NASA Astrophysics Data System (ADS)

    Turner-Evans, Dan

    Over the past five years, the cost of solar panels has dropped drastically and, in concert, the number of installed modules has risen exponentially. However, solar electricity is still more than twice as expensive as electricity from a natural gas plant. Fortunately, wire array solar cells have emerged as a promising technology for further lowering the cost of solar. Si wire array solar cells are formed with a unique, low cost growth method and use 100 times less material than conventional Si cells. The wires can be embedded in a transparent, flexible polymer to create a free-standing array that can be rolled up for easy installation in a variety of form factors. Furthermore, by incorporating multijunctions into the wire morphology, higher efficiencies can be achieved while taking advantage of the unique defect relaxation pathways afforded by the 3D wire geometry. The work in this thesis shepherded Si wires from undoped arrays to flexible, functional large area devices and laid the groundwork for multijunction wire array cells. Fabrication techniques were developed to turn intrinsic Si wires into full p-n junctions and the wires were passivated with a-Si:H and a-SiNx:H. Single wire devices yielded open circuit voltages of 600 mV and efficiencies of 9%. The arrays were then embedded in a polymer and contacted with a transparent, flexible, Ni nanoparticle and Ag nanowire top contact. The contact connected >99% of the wires in parallel and yielded flexible, substrate free solar cells featuring hundreds of thousands of wires. Building on the success of the Si wire arrays, GaP was epitaxially grown on the material to create heterostructures for photoelectrochemistry. These cells were limited by low absorption in the GaP due to its indirect bandgap, and poor current collection due to a diffusion length of only 80 nm. However, GaAsP on SiGe offers a superior combination of materials, and wire architectures based on these semiconductors were investigated for multijunction

  4. Preparation of high temperature superconducting coated wires by dipping and post annealing

    SciTech Connect

    Provenzano, V.; Singh, A.K.; Imam, M.A.; Tritt, T.M.

    1992-04-14

    This patent describes a process for coating a film on a wire substrate, it comprises: melting a superconducting metal oxide mixture in a crucible to form a melt; coating the substrate with a diffusion barrier; dipping the coated wire substrate into the melt; cooling the coated wire substrate at a rate sufficiently slow to avoid thermal shock and hot cracking; and post-annealing the cooled, coated wire substrate to relieve thermal stresses in the coating, whereupon the superconducting metal-oxide mixture forms a perovskite coating upon the wire substrate.

  5. Theoretical simulation of a 2 micron airborne solid state laser anemometer

    NASA Technical Reports Server (NTRS)

    Imbert, Beatrice; Cariou, Jean-Pierre

    1992-01-01

    In the near future, military aircraft will need to know precisely their true airspeed in order to optimize flight conditions. In comparison with classical anemometer probes, an airborne Doppler lidar allows measurement of the air velocity without influence from aircraft aerodynamic disturbance. While several demonstration systems of heterodyne detection using a CO2 laser have been reported, improvements in the technology of solid state lasers have recently opened up the possibility that these devices can be used as an alternative to CO2 laser systems. In particular, a diode pumped Tm:Ho:YAG laser allows a reliable compact airborne system with an eye safe wavelength (lambda = 2.09 microns) to be achieved. The theoretical study of performances of a coherent lidar using a solid state diode pumped Tm:Ho:YAG laser, caled SALSA, for measuring aircraft airspeed relative to atmospheric aerosols is described. A computer simulation was developed in order to modelize the Doppler anemometer in the function of atmospheric propagation and optical design. A clever analysis of the power budget on the detector area allows optical characteristic parameters of the system to be calculated, and then it can be used to predict performances of the Doppler system. Estimating signal to noise ratios (SNR) and heterodyne efficiency provides the available energy of speed measurement as well as a useful measurement of the alignment of the backscattered and reference fields on the detector.

  6. Laser transit anemometer measurements on a slender cone in the Langley unitary plan wind tunnel

    NASA Technical Reports Server (NTRS)

    Humphreys, William M., Jr.; Hunter, William W., Jr.; Covell, Peter F.; Nichols, Cecil E., Jr.

    1990-01-01

    A laser transit anemometer (LTA) system was used to probe the boundary layer on a slender (5 degree half angle) cone model in the Langley unitary plan wind tunnel. The anemometer system utilized a pair of laser beams with a diameter of 40 micrometers spaced 1230 micrometers apart to measure the transit times of ensembles of seeding particles using a cross-correlation technique. From these measurements, boundary layer profiles around the model were constructed and compared with CFD calculations. The measured boundary layer profiles representing the boundary layer velocity normalized to the edge velocity as a function of height above the model surface were collected with the model at zero angle of attack for four different flow conditions, and were collected in a vertical plane that bisected the model's longitudinal center line at a location 635 mm from the tip of the forebody cone. The results indicate an excellent ability of the LTA system to make velocity measurements deep into the boundary layer. However, because of disturbances in the flow field caused by onboard seeding, premature transition occurred implying that upstream seeding is mandatory if model flow field integrity is to be maintained. A description and results of the flow field surveys are presented.

  7. Intermittent turbulence events observed with a sonic anemometer and minisodar during CASES99.

    SciTech Connect

    Coulter, R. L.; Doran, J. C.

    2000-05-12

    The Cooperative Air Surface Exchange Study 1999 (CASES99), designed to investigate in detail the nocturnal boundary layer (NBL) of the atmosphere with particular emphasis on turbulence and turbulence events, took place during October 1999, within the Atmospheric Boundary Layer Experiments (ABLE) region east of Wichita KS. The principal measurement site was a heavily instrumented 2-km square located near Leon (LE), KS, but additional sites at Smileyberg (SM) and Beaumont (BE) were also used. The authors augmented the normal ABLE measurements at Beaumont (radar wind profiler, minisodar, 10-m meteorological tower, precipitation gauge) with a sonic anemometer mounted on the tower, 7 m above the surface. For this campaign, the minisodar data were saved in single-pulse mode with no averaging. The Beaumont site is within gently rolling rangeland used primarily for grazing. The site is on a flat plain rising gradually to the east.The Flint Hills escarpment, located approximately 2 km to the east, marks the highest point in, and the eastern boundary of, the Walnut River watershed. Although most terrain features are subtle, terrain effects on atmospheric flows are still possible, particularly in stable conditions. The intent was to observe turbulence and, hopefully, turbulence events with the sonic anemometer and minisodar. The horizontal extent of these occurrences can be studied by including the Beaumont data with those obtained at the Leon site. In this report the authors are concerned with the occurrence of intermittent turbulence.

  8. Commercial and Industrial Wiring.

    ERIC Educational Resources Information Center

    Kaltwasser, Stan; Flowers, Gary

    This module is the third in a series of three wiring publications, includes additional technical knowledge and applications required for job entry in the commercial and industrial wiring trade. The module contains 15 instructional units that cover the following topics: blueprint reading and load calculations; tools and equipment; service;…

  9. 2016 MOST WIRED.

    PubMed

    Barr, Paul; Butcher, Lola; Hoppszallern, Suzanna

    2016-07-01

    This year's IT survey shows that hospitals are aggressively fighting cyber crime and looking for ways to use data to help in the transition to value-based care. Find out who made the 2016 lists of Most Wired, Most Advanced, Most Improved and Most Wired-Small and Rural. PMID:27526506

  10. 2016 MOST WIRED.

    PubMed

    Barr, Paul; Butcher, Lola; Hoppszallern, Suzanna

    2016-07-01

    This year's IT survey shows that hospitals are aggressively fighting cyber crime and looking for ways to use data to help in the transition to value-based care. Find out who made the 2016 lists of Most Wired, Most Advanced, Most Improved and Most Wired-Small and Rural.

  11. Water Desalination with Wires.

    PubMed

    Porada, S; Sales, B B; Hamelers, H V M; Biesheuvel, P M

    2012-06-21

    We show the significant potential of water desalination using a novel capacitive wire-based technology in which anode/cathode wire pairs are constructed from coating a thin porous carbon electrode layer on top of electrically conducting rods (or wires). By alternately dipping an array of electrode pairs in freshwater with and in brine without an applied cell voltage, we create an ion adsorption/desorption cycle. We show experimentally how in six subsequent cycles we can reduce the salinity of 20 mM feed (brackish) water by a factor of 3, while application of a cation exchange membrane on the cathode wires makes the desalination factor increase to 4. Theoretical modeling rationalizes the experimental findings, and predicts that system performance can be significantly enhanced by material modifications. To treat large volumes of water, multiple stacks of wire pairs can be used simultaneously in a "merry-go-round" operational mode.

  12. International space station wire program

    NASA Technical Reports Server (NTRS)

    May, Todd

    1995-01-01

    Hardware provider wire systems and current wire insulation issues for the International Space Station (ISS) program are discussed in this viewgraph presentation. Wire insulation issues include silicone wire contamination, Tefzel cold temperature flexibility, and Russian polyimide wire insulation. ISS is a complex program with hardware developed and managed by many countries and hundreds of contractors. Most of the obvious wire insulation issues are known by contractors and have been precluded by proper selection.

  13. Wire tension versus wire frequency: an experimental Ilizarov frame study.

    PubMed

    La Russa, Valentina; Skallerud, Bjørn; Klaksvik, Jomar; Foss, Olav A

    2010-08-26

    Stability of an Ilizarov frame highly depends on maintenance of adequate tension in the wires. Wire tension should be measured accurately in experimental laboratory studies when new types of wire fixators are tested. In this study, 20 wires were tested using two different wire fixators. The wires were sequentially tensioned from 0 to 1275 N in 50 N intervals. For each tension value, corresponding vibration frequency was recorded. We then described the relationship between wire tension and wire vibration frequency in an empirical equation (R(2)=99.8). Wire vibration frequency can also be described theoretically by the Euler-Bernoulli equation for a thin beam. Theoretical frequencies were calculated and compared with corresponding experimental frequencies. A close agreement was found (95% limits of agreement, +/-3.2 Hz). This empirical equation represents a simple tool, applicable when investigating the effect of new wire fixators, pre-tensioning and frame constructions on wire tension. PMID:20472242

  14. Development of superconducting YBa2Cu3O(x) wires with low resistance electrical contacts

    NASA Technical Reports Server (NTRS)

    Buoncristiani, A. M.; Byvik, C. E.; Caton, R.; Selim, R.; Lee, B. I.; Modi, V.; Sherrill, M.; Leigh, H. D.; Fain, C. C.; Lewis, G.

    1993-01-01

    Materials exhibiting superconductivity above liquid nitrogen temperatures (77 K) will enable new applications of this phenomena. One of the first commercial applications of this technology will be superconducting magnets for medical imaging. However, a large number of aerospace applications of the high temperature superconducting materials have also been identified. These include magnetic suspension and balance of models in wind tunnels and resistanceless leads to anemometers. The development of superconducting wires fabricated from the ceramic materials is critical for these applications. The progress in application of a patented fiber process developed by Clemson University for the fabrication of superconducting wires is reviewed. The effect of particle size and heat treatment on the quality of materials is discussed. Recent advances made at Christopher Newport College in the development of micro-ohm resistance electrical contacts which are capable of carrying the highest reported direct current to this material is presented.

  15. Next Generation Wiring

    NASA Technical Reports Server (NTRS)

    Medelius, Petro; Jolley, Scott; Fitzpatrick, Lilliana; Vinje, Rubiela; Williams, Martha; Clayton, LaNetra; Roberson, Luke; Smith, Trent; Santiago-Maldonado, Edgardo

    2007-01-01

    Wiring is a major operational component on aerospace hardware that accounts for substantial weight and volumetric space. Over time wire insulation can age and fail, often leading to catastrophic events such as system failure or fire. The next generation of wiring must be reliable and sustainable over long periods of time. These features will be achieved by the development of a wire insulation capable of autonomous self-healing that mitigates failure before it reaches a catastrophic level. In order to develop a self-healing insulation material, three steps must occur. First, methods of bonding similar materials must be developed that are capable of being initiated autonomously. This process will lead to the development of a manual repair system for polyimide wire insulation. Second, ways to initiate these bonding methods that lead to materials that are similar to the primary insulation must be developed. Finally, steps one and two must be integrated to produce a material that has no residues from the process that degrades the insulating properties of the final repaired insulation. The self-healing technology, teamed with the ability to identify and locate damage, will greatly improve reliability and safety of electrical wiring of critical systems. This paper will address these topics, discuss the results of preliminary testing, and remaining development issues related to self-healing wire insulation.

  16. Premelting of thin wires

    NASA Astrophysics Data System (ADS)

    Gülseren, O.; Ercolessi, F.; Tosatti, E.

    1995-03-01

    We have investigated the melting behavior of thin lead wires using molecular dynamics. We find that-in analogy with cluster melting-the melting temperature Tm(R) of a wire with radius R is lower than that of a bulk solid Tbm by Tm(R)=Tbm-c/R. Surface melting effects, with formation of a thin skin of highly diffusive atoms at the wire surface, are observed. The diffusivity is lower over (111)-oriented faces, and higher at (110) and (100) rounded areas. The possible relevance to recent results on nonrupturing thin necks between a scanning tunnel microscope tip and a warm surface is addressed.

  17. Using a Swinging Vane Anemometer to Measure Airflow. Module 14. Vocational Education Training in Environmental Health Sciences.

    ERIC Educational Resources Information Center

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on using a swinging vane anemometer to measure airflow. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming each…

  18. Fabrication of Wire Mesh Heat Exchangers for Waste Heat Recovery Using Wire-Arc Spraying

    NASA Astrophysics Data System (ADS)

    Rezaey, R.; Salavati, S.; Pershin, L.; Coyle, T.; Chandra, S.; Mostaghimi, J.

    2014-04-01

    Waste heat can be recovered from hot combustion gases using water-cooled heat exchangers. Adding fins to the external surfaces of the water pipes inserted into the hot gases increases their surface area and enhances heat transfer, increasing the efficiency of heat recovery. A method of increasing the heat transfer surface area has been developed using a twin wire-arc thermal spray system to generate a dense, high-strength coating that bonds wire mesh to the outside surfaces of stainless steel pipes through which water passes. At the optimum spray distance of 150 mm, the oxide content, coating porosity, and the adhesion strength of the coating were measured to be 7%, 2%, and 24 MPa, respectively. Experiments were done in which heat exchangers were placed inside a high-temperature oven with temperature varying from 300 to 900 °C. Several different heat exchanger designs were tested to estimate the total heat transfer in each case. The efficiency of heat transfer was found to depend strongly on the quality of the bond between the wire meshes and pipes and the size of openings in the wire mesh.

  19. Laser anemometer measurements in a transonic axial-flow fan rotor

    NASA Technical Reports Server (NTRS)

    Strazisar, Anthony J.; Wood, Jerry R.; Hathaway, Michael D.; Suder, Kenneth L.

    1989-01-01

    Laser anemometer surveys were made of the 3-D flow field in NASA rotor 67, a low aspect ratio transonic axial-flow fan rotor. The test rotor has a tip relative Mach number of 1.38. The flowfield was surveyed at design speed at near peak efficiency and near stall operating conditions. Data is presented in the form of relative Mach number and relative flow angle distributions on surfaces of revolution at nine spanwise locations evenly spaced from hub to tip. At each spanwise location, data was acquired upstream, within, and downstream of the rotor. Aerodynamic performance measurements and detailed rotor blade and annulus geometry are also presented so that the experimental results can be used as a test case for 3-D turbomachinery flow analysis codes.

  20. Monitoring the optical turbulence in the surface layer at Dome C, Antarctica, with sonic anemometers

    NASA Astrophysics Data System (ADS)

    Aristidi, E.; Vernin, J.; Fossat, E.; Schmider, F.-X.; Travouillon, T.; Pouzenc, C.; Traullé, O.; Genthon, C.; Agabi, A.; Bondoux, E.; Challita, Z.; Mékarnia, D.; Jeanneaux, F.; Bouchez, G.

    2015-12-01

    The optical turbulence above Dome C in winter is mainly concentrated in the first tens of metres above the ground. Properties of this so-called surface layer (SL) were investigated during the period 2007-2012 by a set of sonic anemometers placed on a 45 m high tower. We present the results of this long-term monitoring of the refractive index structure constant C_n^2 within the SL, and confirm its thickness of 35 m. We give statistics of the contribution of the SL to the seeing and coherence time. We also investigate properties of large-scale structure functions of the temperature and show evidence of a second inertial zone at kilometric spatial scales.

  1. A directional cylindrical anemometer with four sets of differential pressure sensors

    NASA Astrophysics Data System (ADS)

    Liu, C.; Du, L.; Zhao, Z.

    2016-03-01

    This paper presents a solid-state directional anemometer for simultaneously measuring the speed and direction of a wind in a plane in a speed range 1-40 m/s. This instrument has a cylindrical shape and works by detecting the pressure differences across diameters of the cylinder when exposed to wind. By analyzing our experimental data in a Reynolds number regime 1.7 × 103-7 × 104, we figure out the relationship between the pressure difference distribution and the wind velocity. We propose a novel and simple solution based on the relationship and design an anemometer which composes of a circular cylinder with four sets of differential pressure sensors, tubes connecting these sensors with the cylinder's surface, and corresponding circuits. In absence of moving parts, this instrument is small and immune of friction. It has simple internal structures, and the fragile sensing elements are well protected. Prototypes have been fabricated to estimate performance of proposed approach. The power consumption of the prototype is less than 0.5 W, and the sample rate is up to 31 Hz. The test results in a wind tunnel indicate that the maximum relative speed measuring error is 5% and the direction error is no more than 5° in a speed range 2-40 m/s. In theory, it is capable of measuring wind up to 60 m/s. When the air stream goes slower than 2 m/s, the measuring errors of directions are slightly greater, and the performance of speed measuring degrades but remains in an acceptable range of ±0.2 m/s.

  2. A directional cylindrical anemometer with four sets of differential pressure sensors.

    PubMed

    Liu, C; Du, L; Zhao, Z

    2016-03-01

    This paper presents a solid-state directional anemometer for simultaneously measuring the speed and direction of a wind in a plane in a speed range 1-40 m/s. This instrument has a cylindrical shape and works by detecting the pressure differences across diameters of the cylinder when exposed to wind. By analyzing our experimental data in a Reynolds number regime 1.7 × 10(3)-7 × 10(4), we figure out the relationship between the pressure difference distribution and the wind velocity. We propose a novel and simple solution based on the relationship and design an anemometer which composes of a circular cylinder with four sets of differential pressure sensors, tubes connecting these sensors with the cylinder's surface, and corresponding circuits. In absence of moving parts, this instrument is small and immune of friction. It has simple internal structures, and the fragile sensing elements are well protected. Prototypes have been fabricated to estimate performance of proposed approach. The power consumption of the prototype is less than 0.5 W, and the sample rate is up to 31 Hz. The test results in a wind tunnel indicate that the maximum relative speed measuring error is 5% and the direction error is no more than 5° in a speed range 2-40 m/s. In theory, it is capable of measuring wind up to 60 m/s. When the air stream goes slower than 2 m/s, the measuring errors of directions are slightly greater, and the performance of speed measuring degrades but remains in an acceptable range of ±0.2 m/s. PMID:27036817

  3. A directional cylindrical anemometer with four sets of differential pressure sensors.

    PubMed

    Liu, C; Du, L; Zhao, Z

    2016-03-01

    This paper presents a solid-state directional anemometer for simultaneously measuring the speed and direction of a wind in a plane in a speed range 1-40 m/s. This instrument has a cylindrical shape and works by detecting the pressure differences across diameters of the cylinder when exposed to wind. By analyzing our experimental data in a Reynolds number regime 1.7 × 10(3)-7 × 10(4), we figure out the relationship between the pressure difference distribution and the wind velocity. We propose a novel and simple solution based on the relationship and design an anemometer which composes of a circular cylinder with four sets of differential pressure sensors, tubes connecting these sensors with the cylinder's surface, and corresponding circuits. In absence of moving parts, this instrument is small and immune of friction. It has simple internal structures, and the fragile sensing elements are well protected. Prototypes have been fabricated to estimate performance of proposed approach. The power consumption of the prototype is less than 0.5 W, and the sample rate is up to 31 Hz. The test results in a wind tunnel indicate that the maximum relative speed measuring error is 5% and the direction error is no more than 5° in a speed range 2-40 m/s. In theory, it is capable of measuring wind up to 60 m/s. When the air stream goes slower than 2 m/s, the measuring errors of directions are slightly greater, and the performance of speed measuring degrades but remains in an acceptable range of ±0.2 m/s.

  4. Splicing Wires Permanently With Explosives

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Kushnick, Anne C.

    1990-01-01

    Explosive joining process developed to splice wires by enclosing and metallurgically bonding wires within copper sheets. Joints exhibit many desirable characteristics, 100-percent conductivity and strength, no heat-induced annealing, no susceptibility to corrosion in contacts between dissimilar metals, and stability at high temperature. Used to join wires to terminals, as well as to splice wires. Applicable to telecommunications industry, in which millions of small wires spliced annually.

  5. Transient hot-film sensor response in a shock tube

    NASA Technical Reports Server (NTRS)

    Roberts, A. S., Jr.; Ortgies, K. R.; Gartenberg, E.

    1989-01-01

    Shock tube experiments were performed to determine the response of a hot-film sensor, mounted flush on the side wall of a shock tube, to unsteady flow behind a normal shock wave. The present experiments attempt to isolate the response of the anemometer due only to the change in convective heat transfer at the hot-film surface. The experiments, performed at low supersonic shock speeds in air, are described along with the data acquisition procedure. The change in convective heat transfer is deduced from the data and the results are compared with those from transient boundary layer theory and another set of experimental results. Finally, a transient local heat transfer coefficient is formulated for use as the forcing function in a hot-film sensor instrument model simulation.

  6. Experimental investigation of boundary layer transition on rotating cones in axial flow in 0 and 35 degrees angle of attack

    NASA Astrophysics Data System (ADS)

    Kargar, Ali; Mansour, Kamyar

    2015-11-01

    In this paper, experimental results using hot wire anemometer and smoke visualization are presented. The results obtained from the hot wire anemometer for critical Reynolds number and transitional Reynolds number are compared with previous results. Excellent agreement is found for the transitional Reynolds number. The results for the transitional Reynolds number are also compared to previous linear stability results. The results from the smoke visualization clearly show the crossflow vortices which arise in the transition process from a laminar to a turbulent flow. A non-zero angle of attack is also considered. we compare our results by linear stability theory which was done by. We just emphasis. Also we compare visualization and hot wire anemometer results graphically, our goal in this paper is to check reliability of using hot wire anemometer and smoke visualization in stability problem and check reliability of linear stability theory for this two cases and compare our results with some trusty experimental works.

  7. Liquid ``Wires" for Microfluidics

    NASA Astrophysics Data System (ADS)

    Kellis, Nathan; Mazzeo, Aaron; Mazzeo, Brian

    2009-10-01

    We demonstrate liquid ``wires'' in a simple solution measurement device. This device highlights the possibility of fabricating liquid circuits. These ``wires'' were formed by filling micro-milled PMMA channels with 5M NaCl solution. Wires were connected to these salt solution channels; the impedance of a test channel filled with solution was measured by an HP 4294A Impedance Analyzer. Deionized water, 2-propanol, and 5M NaCl were measured. Numerical simulations were performed on the channel cross-section to determine the predicted impedance of the device. The simulated results were compared to the experimental data. Graphs of simulations and experiments are presented for the frequency range 1 KHz to 110 MHz. The data show electrode polarization at the electrode-electrolyte interface, as well as parasitic capacitance inherent in the experimental arrangement.

  8. Wire brush fastening device

    DOEpatents

    Meigs, R.A.

    1995-09-19

    A fastening device is provided which is a variation on the conventional nut and bolt. The bolt has a longitudinal axis and threading helically affixed thereon along the longitudinal axis. A nut having a bore extending therethrough is provided. The bore of the nut has a greater diameter than the diameter of the bolt so the bolt can extend through the bore. An array of wire bristles are affixed within the bore so as to form a brush. The wire bristles extend inwardly from the bore and are constructed and arranged of the correct size, length and stiffness to guide the bolt within the bore and to restrain the bolt within the bore as required. A variety of applications of the wire brush nut are disclosed, including a bolt capture device and a test rig apparatus. 13 figs.

  9. Wire brush fastening device

    DOEpatents

    Meigs, Richard A.

    1995-01-01

    A fastening device is provided which is a variation on the conventional nut and bolt. The bolt has a longitudinal axis and threading helically affixed thereon along the longitudinal axis. A nut having a bore extending therethrough is provided. The bore of the nut has a greater diameter than the diameter of the bolt so the bolt can extend through the bore. An array of wire bristles are affixed within the bore so as to form a brush. The wire bristles extend inwardly from the bore and are constructed and arranged of the correct size, length and stiffness to guide the bolt within the bore and to restrain the bolt within the bore as required. A variety of applications of the wire brush nut are disclosed, including a bolt capture device and a test rig apparatus.

  10. Hot Groups.

    ERIC Educational Resources Information Center

    Vail, Kathleen

    1996-01-01

    Collaborators sparked by creative ideas and obsessed by a common task may not realize they're part of a "hot group"--a term coined by business professors Harold J. Leavitt and Jean Lipman-Blumen. Spawned by group decision making and employee empowerment, hot groups can flourish in education settings. They're typically small, short lived, and goal…

  11. Flying wires at Fermilab

    SciTech Connect

    Gannon, J.; Crawford, C.; Finley, D.; Flora, R.; Groves, T.; MacPherson, M.

    1989-03-01

    Transverse beam profile measurement systems called ''Flying Wires'' have been installed and made operational in the Fermilab Main Ring and Tevatron accelerators. These devices are used routinely to measure the emittance of both protons and antiprotons throughout the fill process, and for emittance growth measurements during stores. In the Tevatron, the individual transverse profiles of six proton and six antiproton bunches are obtained simultaneously, with a single pass of the wire through the beam. Essential features of the hardware, software, and system operation are explained in the rest of the paper. 3 refs., 4 figs.

  12. Three component laser anemometer measurements in an annular cascade of core turbine vanes with contoured end wall

    NASA Technical Reports Server (NTRS)

    Goldman, Louis J.; Seasholtz, Richard G.

    1988-01-01

    The three mean velocity components were measured in a full-scale annular turbine stator cascade with contoured hub end wall using a newly developed laser anemometer system. The anemometer consists of a standard fringe configuration using fluorescent seed particles to measure the axial and tangential components. The radial component is measured with a scanning confocal Fabry-Perot interferometer. These two configurations are combined in a single optical system that can operate simultaneously in a backscatter mode through a single optical access port. Experimental measurements were obtained both within and downstream of the stator vane row and compared with calculations from a three-dimensional inviscid computer program. In addition, detailed calibration procedures are described that were used, prior to the experiment, to accurately determine the laser beam probe volume location relative to the cascade hardware.

  13. Combined fringe and Fabry-Perot laser anemometer for three component velocity measurements in turbine stator cascade facility

    NASA Technical Reports Server (NTRS)

    Seasholtz, R. G.; Goldman, L. J.

    1986-01-01

    A laser anemometer is described that was developed for use in a 508 mm diameter annular turbine stator cascade facility. All three velocity components are measured through a single restricted optical port, both within the stator vane row and downstream of the vanes. The measurements are made through a cylindrical window in the casing that matches the tip radius of the cascade. The stator tested has a contoured hub endwall that results in a large radial flow near the hub. The anemometer uses a standard fringe configuration (LFA) with a fluorescent aerosol seed to measure the axial and circumferential velocity components. The radial component is measured with a confocal Fabry-Perot interferometer. The two configurations are combined in a single optical system and can operate simultaneously. Data are presented to illustrate the capabilities of the system.

  14. Wiring for space applications program

    NASA Technical Reports Server (NTRS)

    Hammoud, Ahmad

    1994-01-01

    The insulation testing and analysis consists of: identifying and prioritizing NASA wiring requirements; selecting candidate wiring constructions; developing test matrix and formulating test program; managing, coordinating, and conducting tests; and analyzing and documenting data, establishing guidelines and recommendations.

  15. One hundred angstrom niobium wire

    NASA Technical Reports Server (NTRS)

    Cline, H. E.; Rose, R. M.; Wulff, J.

    1968-01-01

    Composite of fine niobium wires in copper is used to study the size and proximity effects of a superconductor in a normal matrix. The niobium rod was drawn to a 100 angstrom diameter wire on a copper tubing.

  16. Wired To Flex.

    ERIC Educational Resources Information Center

    Fickes, Michael

    2000-01-01

    Discusses wire and cable management solutions school construction committees can use that do not limit flexibility. Topics cover such areas as using perimeter raceways in classrooms, incorporating a flexible communications cabling infrastructure in to the initial design, and answering the question of how to meet future requirements and…

  17. Basic Wiring. Second Edition.

    ERIC Educational Resources Information Center

    Kaltwasser, Stan; And Others

    This guide is designed to assist teachers conducting a foundation course to prepare students for additional courses of training for entry-level employment in either the residential or commercial and industrial wiring trades. Included in the guide are 17 instructional units and the following sections of information for teachers: guidelines in using…

  18. A World without Wires

    ERIC Educational Resources Information Center

    Panettieri, Joseph C.

    2006-01-01

    The wireless bandwagon is rolling across Mississippi, picking up a fresh load of converts and turning calamity into opportunity. Traditional wired school networks, many of which unraveled during Hurricane Katrina, are giving way to advanced wireless mesh networks that frequently include voice-over-IP (VoIP) capabilities. Vendor funding is helping…

  19. Residential Wiring. Second Edition.

    ERIC Educational Resources Information Center

    Taylor, Mark; And Others

    This guide is designed to assist teachers conducting a course to prepare students for entry-level employment in the residential wiring trade. Included in the guide are six instructional units and the following sections of information for teachers: guidelines in using the unit components; academic and workplace skills classifications and…

  20. Improved wire chamber

    DOEpatents

    Atac, M.

    1987-05-12

    An improved gas mixture for use with proportional counter devices, such as Geiger-Mueller tubes and drift chambers. The improved gas mixture provides a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor. 2 figs.

  1. NewsWire, 2002.

    ERIC Educational Resources Information Center

    Byrom, Elizabeth, Ed.; Bingham, Margaret, Ed.; Bowman, Gloria, Ed.; Shoemaker, Dan, Ed.

    2002-01-01

    This document presents the 3 2002 issues of the newsletter "NewsWire," (volume 5). Issue Number One focuses on collaborative Web projects. This issue begins with descriptions of four individual projects: "iEARN"; "Operation RubyThroat"; "Follow the Polar Huskies!"; and "Log in Your Animal Roadkill!" Features that follow include: "Bringing the…

  2. Wire EDM for Refractory Materials

    NASA Technical Reports Server (NTRS)

    Zellars, G. R.; Harris, F. E.; Lowell, C. E.; Pollman, W. M.; Rys, V. J.; Wills, R. J.

    1982-01-01

    In an attempt to reduce fabrication time and costs, Wire Electrical Discharge Machine (Wire EDM) method was investigated as tool for fabricating matched blade roots and disk slots. Eight high-strength nickel-base superalloys were used. Computer-controlled Wire EDM technique provided high quality surfaces with excellent dimensional tolerances. Wire EDM method offers potential for substantial reductions in fabrication costs for "hard to machine" alloys and electrically conductive materials in specific high-precision applications.

  3. Three-dimensional laser Doppler anemometer measurements of a jet in a crossflow

    NASA Technical Reports Server (NTRS)

    Snyder, P.; Orloff, K. L.

    1984-01-01

    A three-dimensional laser Doppler anemometer (3D-LDA) was used in a wind tunnel to measure a jet in a crossflow. Measurements were made in the vicinity of a 5-cm-diam jet which issued normally into a 10.65 m/sec wind tunnel crossflow; the velocity ratio Vjet/Vinf was 8. Detailed lateral surveys were made at two elevations (z = cm and 2 cm); both elevations were within the region affected by the boundary layer on the plate. The results are believed to provide reliable velocity field information in the boundary layer of the jet in a crossflow. Turbulence information also is available and believed to be roughly correct, although it may be subject to broadening effects for the lower values of turbulence. A weak vortex pair was observed in the wake at the plate surface. This structure existed in the boundary layer and built confidence because the 3D-LDA was, indeed, able to resolve fine detail in the wake. The capabilities of the 3D-LDA not only allow the making of the velocity surveys, but can be utilized to follow mean streamlines in the flow.

  4. Fast-response fiber-optic anemometer with temperature self-compensation.

    PubMed

    Liu, Guigen; Hou, Weilin; Qiao, Wei; Han, Ming

    2015-05-18

    We report a novel fiber-optic anemometer with self-temperature compensation capability based on a Fabry-Pérot interferometer (FPI) formed by a thin silicon film attached to the end face of a single-mode fiber. Guided in the fiber are a visible laser beam from a 635 nm diode laser used to heat the FPI and a white-light in the infrared wavelength range as the signal light to interrogate the optical length of the FPI. Cooling effects on the heated sensor head by wind is converted to a wavelength blueshift of the reflection spectral fringes of the FPI. Self-temperature-compensated measurement of wind speed is achieved by recording the difference in fringe wavelengths when the heating laser is turned on and then off. Large thermal-optic coefficient and thermal expansion coefficient of silicon render a high sensitivity that can also be easily tuned by altering the heating laser power. Furthermore, the large thermal diffusivity and the small mass of the thin silicon film endow a fast sensor response.

  5. Laser anemometer measurements and computations in an annular cascade of high turning core turbine vanes

    NASA Technical Reports Server (NTRS)

    Goldman, Louis J.; Seasholtz, Richard G.

    1992-01-01

    An advanced laser anemometer (LA) was used to measure the axial and tangential velocity components in an annular cascade of turbine stator vanes designed for a high bypass ratio engine. These vanes were based on a redesign of the first-stage stator, of a two-stage turbine, that produced 75 degrees of flow turning. Tests were conducted on a 0.771 scale model of the engine size stator. The advanced LA fringe system was designed to employ thinner than usual laser beams resulting in a 50-micron-diameter probe volume. Window correction optics were used to ensure that the laser beams did not uncross in passing through the curved optical access port. Experimental LA measurements of velocity and turbulence were obtained both upstream, within, and downstream of the stator vane row at the design exit critical velocity ratio of 0.896 at the hub. Static pressures were also measured on the vane surface. The measurements are compared, where possible with calculations from a 3-D inviscid flow analysis. The data are presented in both graphic and tabulated form so that they may be readily used to compare against other turbomachinery computations.

  6. A parametric study of the beam refraction problems across laser anemometer windows

    NASA Technical Reports Server (NTRS)

    Owen, Albert K.

    1986-01-01

    The experimenter is often required to view flows through a window with a different index of refraction than either the medium being observed or the medium that the laser anemometer is immersed in. The refraction that occurs at the window surfaces may lead to undesirable changes in probe volume position or beam crossing angle and can lead to partial or complete beam uncrossing. This report describes the results of a parametric study of this problem using a ray tracing technique to predict these changes. The windows studied were a flat plate and a simple cylinder. For the flat-plate study: (1) surface thickness, (2) beam crossing angle, (3) bisecting line - surface normal angle, and (4) incoming beam plane surface orientation were varied. For the cylindrical window additional parameters were also varied: (1) probe volume immersion, (2) probe volume off-radial position, and (3) probe volume position out of the r-theta plane of the lens. A number of empirical correlations were deduced to aid the reader in determining the movement, uncrossing, and change in crossing angle for a particular situations.

  7. Fast-response fiber-optic anemometer with temperature self-compensation.

    PubMed

    Liu, Guigen; Hou, Weilin; Qiao, Wei; Han, Ming

    2015-05-18

    We report a novel fiber-optic anemometer with self-temperature compensation capability based on a Fabry-Pérot interferometer (FPI) formed by a thin silicon film attached to the end face of a single-mode fiber. Guided in the fiber are a visible laser beam from a 635 nm diode laser used to heat the FPI and a white-light in the infrared wavelength range as the signal light to interrogate the optical length of the FPI. Cooling effects on the heated sensor head by wind is converted to a wavelength blueshift of the reflection spectral fringes of the FPI. Self-temperature-compensated measurement of wind speed is achieved by recording the difference in fringe wavelengths when the heating laser is turned on and then off. Large thermal-optic coefficient and thermal expansion coefficient of silicon render a high sensitivity that can also be easily tuned by altering the heating laser power. Furthermore, the large thermal diffusivity and the small mass of the thin silicon film endow a fast sensor response. PMID:26074604

  8. 1997 wire development workshop: Proceedings

    SciTech Connect

    1997-04-01

    This conference is divided into the following sections: (1) First Generation Wires I; (2) First Generation Wires II; (3) Coated conductors I; and (4) Coated conductors II. Applications of the superconducting wires include fault current limiters, superconducting motors, transformers, and power transmission lines.

  9. Dental Arch Wire

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Straightening teeth is an arduous process requiring months, often years, of applying corrective pressure by means of arch wires-better known as brace-which may have to be changed several times in the course of treatment. A new method has been developed by Dr. George Andreasen, orthodontist and dental scientist at the University of Iowa. The key is a new type of arch wire material, called Nitinol, with exceptional elasticity which helps reduce the required number of brace changes. An alloy of nickel and titanium, Nitinol was originally developed for aerospace applications by the Naval Ordnance Laboratory, now the Naval Surface Weapons Laboratory, White Oaks, Maryland. NASA subsequently conducted additional research on the properties of Nitinol and on procedures for processing the metal.

  10. From wires to cosmology

    NASA Astrophysics Data System (ADS)

    Amin, Mustafa A.; Baumann, Daniel

    2016-02-01

    We provide a statistical framework for characterizing stochastic particle production in the early universe via a precise correspondence to current conduction in wires with impurities. Our approach is particularly useful when the microphysics is uncertain and the dynamics are complex, but only coarse-grained information is of interest. We study scenarios with multiple interacting fields and derive the evolution of the particle occupation numbers from a Fokker-Planck equation. At late times, the typical occupation numbers grow exponentially which is the analog of Anderson localization for disordered wires. Some statistical features of the occupation numbers show hints of universality in the limit of a large number of interactions and/or a large number of fields. For test cases, excellent agreement is found between our analytic results and numerical simulations.

  11. Wire insulation defect detector

    NASA Technical Reports Server (NTRS)

    Greulich, Owen R. (Inventor)

    2004-01-01

    Wiring defects are located by detecting a reflected signal that is developed when an arc occurs through the defect to a nearby ground. The time between the generation of the signal and the return of the reflected signal provides an indication of the distance of the arc (and therefore the defect) from the signal source. To ensure arcing, a signal is repeated at gradually increasing voltages while the wire being tested and a nearby ground are immersed in a conductive medium. In order to ensure that the arcing occurs at an identifiable time, the signal whose reflection is to be detected is always made to reach the highest potential yet seen by the system.

  12. Plated wire memory subsystem

    NASA Technical Reports Server (NTRS)

    Reynolds, L.; Tweed, H.

    1972-01-01

    The work performed entailed the design, development, construction and testing of a 4000 word by 18 bit random access, NDRO plated wire memory for use in conjunction with a spacecraft imput/output unit and central processing unit. The primary design parameters, in order of importance, were high reliability, low power, volume and weight. A single memory unit, referred to as a qualification model, was delivered.

  13. Superconducting magnet wire

    DOEpatents

    Schuller, Ivan K.; Ketterson, John B.; Banerjee, Indrajit

    1986-01-01

    A superconducting tape or wire with an improved critical field is formed of alternating layers of a niobium-containing superconductor such as Nb, NbTi, Nb.sub.3 Sn or Nb.sub.3 Ge with a thickness in the range of about 0.5-1.5 times its coherence length, supported and separated by layers of copper with each copper layer having a thickness in the range of about 170-600 .ANG..

  14. Wiring for aerospace applications

    NASA Technical Reports Server (NTRS)

    Christian, J. L., Jr.; Dickman, J. E.; Bercaw, R. W.; Myers, I. T.; Hammoud, A. N.; Stavnes, M.; Evans, J.

    1992-01-01

    In this paper, the authors summarize the current state of knowledge of arc propagation in aerospace power wiring and efforts by the National Aeronautics and Space Administration (NASA) towards the understanding of the arc tracking phenomena in space environments. Recommendations will be made for additional testing. A database of the performance of commonly used insulating materials will be developed to support the design of advanced high power missions, such as Space Station Freedom and Lunar/Mars Exploration.

  15. An Analysis of Peak Wind Speed Data from Collocated Mechanical and Ultrasonic Anemometers

    NASA Technical Reports Server (NTRS)

    Short, David A.; Wells, Leonard A.; Merceret, Francis J.; Roeder, William P.

    2005-01-01

    This study focuses on a comparison of peak wind speeds reported by mechanical and ultrasonic anemometers at Cape Canaveral Air Force Station and Kennedy Space Center (CCAFS/KSC) on the east central coast of Florida and Vandenberg Air Force Base (VAFB) on the central coast of California. The legacy mechanical wind instruments on CCAFS/KSC and VAFB weather towers are being changed from propeller-and-vane (CCAFS/KSC) and cup-and-vane (VAFB) sensors to ultrasonic sensors under the Range Standardization and Automation (RSA) program. The wind tower networks on KSC/CCAFS and VAFB have 41 and 27 towers, respectively. Launch Weather Officers, forecasters, and Range Safety analysts at both locations need to understand the performance of the new wind sensors for a myriad of reasons that include weather warnings, watches, advisories, special ground processing operations, launch pad exposure forecasts, user Launch Commit Criteria (LCC) forecasts and evaluations, and toxic dispersion support. The Legacy sensors measure wind speed and direction mechanically. The ultrasonic RSA sensors have no moving parts. Ultrasonic sensors were originally developed to measure very light winds (Lewis and Dover 2004). The technology has evolved and now ultrasonic sensors provide reliable wind data over a broad range of wind speeds. However, because ultrasonic sensors respond more quickly than mechanical sensors to rapid fluctuations in speed, characteristic of gusty wind conditions, comparisons of data from the two sensor types have shown differences in the statistics of peak wind speeds (Lewis and Dover 2004). The 45th Weather Squadron (45 WS) and the 30 WS requested the Applied Meteorology Unit (AMU) to compare data from RSA and Legacy sensors to determine if there are significant differences in peak wind speed information from the two systems.

  16. Magnetoconductance of quantum wires

    NASA Astrophysics Data System (ADS)

    Ferreira, Gerson J.; Sammarco, Filipe; Egues, Carlos

    2010-03-01

    At low temperatures the conductance of a quantum wires exhibit characteristic plate-aus due to the quantization of the transverse modes [1]. In the presence of high in-plane magnetic fields these spin-split transverse modes cross. Recently, these crossings were observed experimentally [2] via measurements of the differential conductance as a function of the gate voltage and the in-plane magnetic-field. These show structures described as either anti-crossings or magnetic phase transitions. Motivated by our previous works on magnetotransport in 2DEGs via the Spin Density Functional Theory (SDFT) [3], here we propose a similar model to investigate the magnetoconductance of quantum wires. We use (i) the SDFT via the Kohn-Sham self-consistent scheme within the local spin density approximation to obtain the electronic structure and (ii) the Landauer-Buettiker formalism to calculate the conductance of a quantum wire. Our results show qualitative agreement with the data of Ref. [2]. [1] B. J. van Wees et al., Phys. Rev. Lett. 60, 848 (1988). [2] A. C. Graham et al., Phys. Rev. Lett. 100, 226804 (2008). [3] H. J. P. Freire, and J. C. Egues, Phys. Rev. Lett. 99, 026801 (2007); G. J. Ferreira, and J. Carlos Egues, J. Supercond. Nov. Mag., in press; G. J. Ferreira, H. J. P. Freire, J. Carlos Egues, submitted.

  17. Dual wire welding torch and method

    SciTech Connect

    Diez, Fernando Martinez; Stump, Kevin S.; Ludewig, Howard W.; Kilty, Alan L.; Robinson, Matthew M.; Egland, Keith M.

    2009-04-28

    A welding torch includes a nozzle with a first welding wire guide configured to orient a first welding wire in a first welding wire orientation, and a second welding wire guide configured to orient a second welding wire in a second welding wire orientation that is non-coplanar and divergent with respect to the first welding wire orientation. A method of welding includes moving a welding torch with respect to a workpiece joint to be welded. During moving the welding torch, a first welding wire is fed through a first welding wire guide defining a first welding wire orientation and a second welding wire is fed through a second welding wire guide defining a second welding wire orientation that is divergent and non-coplanar with respect to the first welding wire orientation.

  18. Manually Operated Welding Wire Feeder

    NASA Technical Reports Server (NTRS)

    Rybicki, Daniel J. (Inventor)

    2001-01-01

    A manual welding wire feeder apparatus comprising a bendable elongate metal frame with a feed roller mounted at the center thereof for rotation about an axis transverse to the longitudinal axis of the frame. The frame ends are turned up as tabs and each provided with openings in alignment with each other and the mid-width center of the roller surface. The tab openings are sized to accommodate welding wire and each extends to a side edge of the tab, both opening on the same side of the frame, whereby welding wire can be side-loaded onto the frame. On the side of the frame, opposite the roller a lock ring handle is attached tangentially and is rotatable about the attachment point and an axis perpendicular to the frame. The device is grasped in the hand normally used to hold the wire. A finger is placed through the loop ring and the frame positioned across the palm and lower fingers. The thumb is positioned atop the wire so it can be moved from the back of the frame across the roller, and towards the front. In doing so, the wire is advanced at a steady rate in axial alignment with the tab openings and roller. To accommodate different wire diameters the frame is bendable about its center in the plane of the frame axis and wire so as to keep the wire in sufficient tension against the roller and to keep the wire fixed when the frame is tilted and thumb pressure released.

  19. Metering Wheel-Wire Track Wire Boom Deployment Mechanism

    NASA Technical Reports Server (NTRS)

    Granoff, Mark S.

    2014-01-01

    The NASA MMS Spin Plane Double Probe (SDP) Deployer utilizes a helical path, rotating Metering Wheel and a spring loaded Wire "Holding" Track to pay out a "fixed end" 57 meter x 1.5 mm diameter Wire Boom stored between concentric storage cylinders. Unlike rotating spool type storage devices, the storage cylinders remain stationary, and the boom wire is uncoiled along the length of the cylinder via the rotation of the Metering Wheel. This uncoiling action avoids the need for slip-ring contacts since the ends of the wire can remain stationary. Conventional fixed electrical connectors (Micro-D type) are used to terminate to operational electronics.

  20. Review of wire chamber aging

    SciTech Connect

    Va'Vra, J.

    1986-02-01

    This paper makes an overview of the wire chamber aging problems as a function of various chamber design parameters. It emphasizes the chemistry point of view and many examples are drawn from the plasma chemistry field as a guidance for a possible effort in the wire chamber field. The paper emphasizes the necessity of variable tuning, the importance of purity of the wire chamber environment, as well as it provides a practical list of presently known recommendations. In addition, several models of the wire chamber aging are qualitatively discussed. The paper is based on a summary talk given at the Wire Chamber Aging Workshop held at LBL, Berkeley on January 16-17, 1986. Presented also at Wire Chamber Conference, Vienna, February 25-28, 1986. 74 refs., 18 figs., 11 tabs.

  1. Hot wire anemometry. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Habercom, G. E., Jr.

    1980-08-01

    Citations include principles; calibrating; circuit diagrams; flow measurement; hypersonic, supersonic, transonic, and subsonic characteristics; boundary layer studies; turbulence; jet, pipe, and tunnel flow; mathematical models; wind tunnel model tests, airport structure simulation; mass transfer and flow stability; probe modifications; flow about geometric forms; flow patterns; and related topics. This updated bibliography contains 249 citations, 28 of which are new entries to the previous edition.

  2. Hot Canyon

    ScienceCinema

    None

    2016-07-12

    This historical film footage, originally produced in the early 1950s as part of a series by WOI-TV, shows atomic research at Ames Laboratory. The work was conducted in a special area of the Laboratory known as the "Hot Canyon."

  3. Hot Canyon

    SciTech Connect

    2012-01-01

    This historical film footage, originally produced in the early 1950s as part of a series by WOI-TV, shows atomic research at Ames Laboratory. The work was conducted in a special area of the Laboratory known as the "Hot Canyon."

  4. Hot Tickets

    ERIC Educational Resources Information Center

    Fox, Bette-Lee; Hoffert, Barbara; Kuzyk, Raya; McCormack, Heather; Williams, Wilda

    2008-01-01

    This article describes the highlights of this year's BookExpo America (BEA) held at the Los Angeles Convention Center. The attendees at BEA had not minded that the air was recycled, the lighting was fluorescent, and the food was bad. The first hot book sighting came courtesy of Anne Rice. Michelle Moran, author of newly published novel, "The…

  5. Plated wire memory subsystem

    NASA Technical Reports Server (NTRS)

    Carpenter, K. H.

    1974-01-01

    The design, construction, and test history of a 4096 word by 18 bit random access NDRO Plated Wire Memory for use in conjunction with a spacecraft input/output and central processing unit is reported. A technical and functional description is given along with diagrams illustrating layout and systems operation. Test data is shown on the procedures and results of system level and memory stack testing, and hybrid circuit screening. A comparison of the most significant physical and performance characteristics of the memory unit versus the specified requirements is also included.

  6. Texture development in Galfenol wire

    NASA Astrophysics Data System (ADS)

    Boesenberg, A. J.; Restorff, J. B.; Wun-Fogle, M.; Sailsbury, H.; Summers, E.

    2013-05-01

    Galfenol (Fe-Ga alloy) wire fabrication provides a low cost alternative to directional solidification methods. This work evaluates the compositional dependence of the wire drawing suitability of Fe-Ga and characterizes the microstructural and magnetic properties of these wires. Wire has been produced with Ga contents between 10 at. % and 17 at. % to allow determination of the ductile to brittle transition (DTBT) in wire manufacture. Published results on chill cast bend specimens indicated that a DTBT occurs at roughly 15 at. % Ga. This DTBT was observed under tensile loading with a corresponding change in fracture behavior from transverse fracture to intergranular fracture. For improved magnetostrictive performance, higher Ga contents are desired, closer to the 17 at. % Ga evaluated in this work. Electron backscattered diffraction B-H loop and resonance measurements as a function of magnetic field (to determine modulus and coupling factor) are presented for as-drawn, furnace, and direct current (DC) annealed wire. Galfenol wire produced via traditional drawing methods is found to have a strong <110> (α) texture parallel to the drawing direction. As-drawn wire was observed to have a lower magnetic permeability and larger hysteresis than DC annealed wire. This is attributed to the presence of a large volume of crystalline defects; such as vacancies and dislocations.

  7. 49 CFR 236.74 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... underground wire. 236.74 Section 236.74 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING... wire; splice in underground wire. Insulated wire shall be protected from mechanical injury....

  8. 49 CFR 236.74 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... underground wire. 236.74 Section 236.74 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING... wire; splice in underground wire. Insulated wire shall be protected from mechanical injury....

  9. 49 CFR 234.241 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... underground wire. 234.241 Section 234.241 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY... of insulated wire; splice in underground wire. Insulated wire shall be protected from...

  10. 49 CFR 236.74 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... underground wire. 236.74 Section 236.74 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING... wire; splice in underground wire. Insulated wire shall be protected from mechanical injury....

  11. 49 CFR 236.74 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... underground wire. 236.74 Section 236.74 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING... wire; splice in underground wire. Insulated wire shall be protected from mechanical injury....

  12. 49 CFR 234.241 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... underground wire. 234.241 Section 234.241 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY... of insulated wire; splice in underground wire. Insulated wire shall be protected from...

  13. 49 CFR 236.74 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... underground wire. 236.74 Section 236.74 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING... wire; splice in underground wire. Insulated wire shall be protected from mechanical injury....

  14. A Comparison of Wind Speed Data from Mechanical and Ultrasonic Anemometers

    NASA Technical Reports Server (NTRS)

    Short, D.; Wells, L.; Merceret, F.; Roeder, W. P.

    2006-01-01

    This study compared the performance of mechanical and ultrasonic anemometers at the Eastern Range (ER; Kennedy Space Center and Cape Canaveral Air Force Station on Florida's Atlantic coast) and the Western Range (WR; Vandenberg Air Force Base on California's Pacific coast). Launch Weather Officers, forecasters, and Range Safety analysts need to understand the performance of wind sensors at the ER and WR for weather warnings, watches, advisories, special ground processing operations, launch pad exposure forecasts, user Launch Commit Criteria (LCC) forecasts and evaluations, and toxic dispersion support. The current ER and WR weather tower wind instruments are being changed from the current propeller-and-vane (ER) and cup-and-vane (WR) sensors to ultrasonic sensors through the Range Standardization and Automation (RSA) program. The differences between mechanical and ultrasonic techniques have been found to cause differences in the statistics of peak wind speed in previous studies. The 45th Weather Squadron (45 WS) and the 30th Weather Squadron (30 WS) requested the Applied Meteorology Unit (AMU) to compare data between RSA and current sensors to determine if there are significant differences. Approximately 3 weeks of Legacy and RSA wind data from each range were used in the study, archived during May and June 2005. The ER data spanned the full diurnal cycle, while the WR data was confined to 1000-1600 local time. The sample of 1-minute data from numerous levels on 5 different towers on each range totaled more than 500,000 minutes of data (482,979 minutes of data after quality control). The 10 towers were instrumented at several levels, ranging from 12 ft to 492 ft above ground level. The RSA sensors were collocated at the same vertical levels as the present sensors and typically within 15 ft horizontally of each another. Data from a total of 53 RSA ultrasonic sensors, collocated with present sensors were compared. The 1-minute average wind speed/direction and the 1

  15. An Analysis of Peak Wind Speed Data from Collocated Mechanical and Ultrasonic Anemometers

    NASA Technical Reports Server (NTRS)

    Short, David A.; Wells, Leonard; Merceret, Francis J.; Roeder, William P.

    2007-01-01

    This study compared peak wind speeds reported by mechanical and ultrasonic anemometers at Cape Canaveral Air Force Station and Kennedy Space Center (CCAFS/KSC) on the east central coast of Florida and Vandenberg Air Force Base (VAFB) on the central coast of California. Launch Weather Officers, forecasters, and Range Safety analysts need to understand the performance of wind sensors at CCAFS/KSC and VAFB for weather warnings, watches, advisories, special ground processing operations, launch pad exposure forecasts, user Launch Commit Criteria (LCC) forecasts and evaluations, and toxic dispersion support. The legacy CCAFS/KSC and VAFB weather tower wind instruments are being changed from propeller-and-vane (CCAFS/KSC) and cup-and-vane (VAFB) sensors to ultrasonic sensors under the Range Standardization and Automation (RSA) program. Mechanical and ultrasonic wind measuring techniques are known to cause differences in the statistics of peak wind speed as shown in previous studies. The 45th Weather Squadron (45 WS) and the 30th Weather Squadron (30 WS) requested the Applied Meteorology Unit (AMU) to compare data between the RSA ultrasonic and legacy mechanical sensors to determine if there are significant differences. Note that the instruments were sited outdoors under naturally varying conditions and that this comparison was not designed to verify either technology. Approximately 3 weeks of mechanical and ultrasonic wind data from each range from May and June 2005 were used in this study. The CCAFS/KSC data spanned the full diurnal cycle, while the VAFB data were confined to 1000-1600 local time. The sample of 1-minute data from numerous levels on five different towers on each range totaled more than 500,000 minutes of data (482,979 minutes of data after quality control). The ten towers were instrumented at several levels, ranging from 12 ft to 492 ft above ground level. The ultrasonic sensors were collocated at the same vertical levels as the mechanical sensors and

  16. Soft magnetic wires

    NASA Astrophysics Data System (ADS)

    Vázquez, M.

    2001-06-01

    An overview of the present state of the art on the preparation techniques, outstanding magnetic properties and applications of soft magnetic micro and nanowires is presented. Rapid solidification techniques (in-rotating-water quenching and drawing methods) to fabricate amorphous microwires with diameter in the range from 100 down to 1 μm are first described. Electrodeposition is also employed to prepare composite microtubes (magnetic coatings) and to fill porous membranes (diameter of the order of 0.1 μm). Magnetic behaviours of interest are related to the different hysteresis loops of samples: square-shaped loops typical of bistable behaviour, and nearly non-hysteretic loop with well-defined transverse anisotropy field. The role played by magnetic dipolar interactions in the magnetic behaviour of arrays of micro and nanowires is described. A particular analysis is done on the giant magnetoimpedance (GMI) effect in the radio and microwave frequency ranges exhibited by ultrasoft microwires. Finally, a few examples of applications are introduced for magnetostrictive and non-magnetostrictive wires, they are: “magnetoelastic pens”, micromotors; DC current-sensors based on GMI, and sharpened amorphous wire tips in spin polarised scanning tunneling microscopy.

  17. Improved superconducting magnet wire

    DOEpatents

    Schuller, I.K.; Ketterson, J.B.

    1983-08-16

    This invention is directed to a superconducting tape or wire composed of alternating layers of copper and a niobium-containing superconductor such as niobium of NbTi, Nb/sub 3/Sn or Nb/sub 3/Ge. In general, each layer of the niobium-containing superconductor has a thickness in the range of about 0.05 to 1.5 times its coherence length (which for Nb/sub 3/Si is 41 A) with each copper layer having a thickness in the range of about 170 to 600 A. With the use of very thin layers of the niobium composition having a thickness within the desired range, the critical field (H/sub c/) may be increased by factors of 2 to 4. Also, the thin layers of the superconductor permit the resulting tape or wire to exhibit suitable ductility for winding on a magnet core. These compositions are also characterized by relatively high values of critical temperature and therefore will exhibit a combination of useful properties as superconductors.

  18. Estimation of SO{sub 2} dry deposition using turbulence parameters observed by sonic anemometer-thermometer

    SciTech Connect

    Lee, Chong Bum; Kim, Jeong, Sik; Kim, Yong Goog; Cho, Chang Rae; Byun, D.W.

    1996-12-31

    The dry deposition of pollutants can be calculated from the concentration of pollutants in the atmosphere and deposition velocity. To calculate deposition velocity, turbulence parameters such as friction velocity and Monin-Obukhov length are used. However, due to the difficulties in observation of turbulence parameters, usually mean values of wind speed and temperature observed using conventional meteorological instruments are used to estimate the dry deposition. The dry deposition velocity is the function of aerodynamic resistance (R{sub a}), sublayer resistance (R{sub b}), surface resistance (R{sub c}). R{sub a} and R{sub b} are calculated from turbulence parameters and R{sub c} is related to surface characteristics. The purpose of the present study is to compare the dry deposition obtained using the data sets of mean values and turbulence parameters measured by sonic anemometer-thermometer. The field observation was performed for 30 days from October 27 to November 25, 1995. The turbulence parameters were measured by 3 dimensional sonic anemometer-thermometer and mean meteorological variables are obtained at two heights, 2.5 m and 10 m. The results show that the dry deposition velocity is large, in daytime and small in nighttime. The major factor of diurnal variation is Ra. In the daytime the dry deposition velocity calculated using mean meteorological data show relatively similar to the dry deposition velocity calculated using the turbulence data, however there are big differences at night.

  19. Effects of axial heat conduction and material properties on the performance characteristics of a thermal transient anemometer probe

    SciTech Connect

    Bailey, J.L.; Page, R.J.; Acharya, M.

    1995-07-01

    This paper describes an investigation of the axial heat transfer within a thermal transient anemometer probe. A previous study, evaluated the performance characteristics of a thermal transient anemometer system. The study revealed discrepancies between a simplified theory and test results in the development of a universal calibration curve for probes of varying diameters. Although the cause of these discrepancies were left uncertain due to an inadequate theoretical model, the study suggested that axial conduction within the probe could account for the deviations. In this paper, computer simulations are used to further investigate axial heat conduction within the probes. The effect on calibration of axial variations of material properties along the probes is also discussed. Results from the computer simulation are used in lieu of the theoretical model used in the previous study to develop a satisfactory universal calibration curve. The computer simulations provide evidence that there is significant axial heat conduction within the probes, and that this was the cause of the discrepancies noted in the previous study.

  20. The Current in a Wire

    ERIC Educational Resources Information Center

    Thompson, Keith

    2009-01-01

    This little problem arose because I was frustrated with the standard electromagnetism texts, which show the magnetic field due to a current-bearing wire outside the wire [proportional to] 1/r and inside [proportional to] r. However, they never point out that the moving electrons must be influenced by the magnetic field created by the other moving…

  1. Most Wired 2006: measuring value.

    PubMed

    Solovy, Alden

    2006-07-01

    As the Most Wired hospitals incorporate information technology into their strategic plans, they combine a"balanced scorecard"approach with classic business analytics to measure how well IT delivers on their goals. To find out which organizations made this year's 100 Most Wired list, as well as those named in other survey categories, go to the foldout section.

  2. Aircraft wiring program status report

    NASA Technical Reports Server (NTRS)

    Beach, Rex

    1995-01-01

    In this Naval Air Warfare Center (NAWC) Aircraft Division status report, the general and wire and cable component activities, the systems engineering activities, the aircraft wiring lead maintenance activities, the NAVAIR/NASA interface activities, and the Base Realignment and Closure (BRAC) Commission recommendations are presented.

  3. Most Wired 2006: measuring value.

    PubMed

    Solovy, Alden

    2006-07-01

    As the Most Wired hospitals incorporate information technology into their strategic plans, they combine a"balanced scorecard"approach with classic business analytics to measure how well IT delivers on their goals. To find out which organizations made this year's 100 Most Wired list, as well as those named in other survey categories, go to the foldout section. PMID:16915970

  4. Wire and Packing Tape Sandwiches

    ERIC Educational Resources Information Center

    Rabinowitz, Sandy

    2009-01-01

    In this article, the author describes how students can combine craft wire with clear packing tape to create a two-dimensional design that can be bent and twisted to create a three-dimensional form. Students sandwich wire designs between two layers of tape. (Contains 1 online resource.)

  5. Wire metamaterials: physics and applications.

    PubMed

    Simovski, Constantin R; Belov, Pavel A; Atrashchenko, Alexander V; Kivshar, Yuri S

    2012-08-16

    The physics and applications of a broad class of artificial electromagnetic materials composed of lattices of aligned metal rods embedded in a dielectric matrix are reviewed. Such structures are here termed wire metamaterials. They appear in various settings and can operate from microwaves to THz and optical frequencies. An important group of these metamaterials is a wire medium possessing extreme optical anisotropy. The study of wire metamaterials has a long history, however, most of their important and useful properties have been revealed and understood only recently, especially in the THz and optical frequency ranges where the wire media correspond to the lattices of microwires and nanowires, respectively. Another group of wire metamaterials are arrays and lattices of nanorods of noble metals whose unusual properties are driven by plasmonic resonances.

  6. Welding wire pressure sensor assembly

    NASA Technical Reports Server (NTRS)

    Morris, Timothy B. (Inventor); Milly, Peter F., Sr. (Inventor); White, J. Kevin (Inventor)

    1994-01-01

    The present invention relates to a device which is used to monitor the position of a filler wire relative to a base material being welded as the filler wire is added to a welding pool. The device is applicable to automated welding systems wherein nonconsumable electrode arc welding processes are utilized in conjunction with a filler wire which is added to a weld pool created by the electrode arc. The invention senses pressure deviations from a predetermined pressure between the filler wire and the base material, and provides electrical signals responsive to the deviations for actuating control mechanisms in an automatic welding apparatus so as to minimize the pressure deviation and to prevent disengagement of the contact between the filler wire and the base material.

  7. Apollo experience report: Electrical wiring subsystem

    NASA Technical Reports Server (NTRS)

    White, L. D.

    1975-01-01

    The general requirements of the electrical wiring subsystems and the problem areas and solutions that occurred during the major part of the Apollo Program are detailed in this report. The concepts and definitions of specific requirements for electrical wiring; wire-connecting devices; and wire-harness fabrication, checkout, and installation techniques are discussed. The design and development of electrical wiring and wire-connecting devices are described. Mission performance is discussed, and conclusions and recommendations for future programs are presented.

  8. Internal wire guide for GTAW welding

    NASA Technical Reports Server (NTRS)

    Morgan, Gene E. (Inventor); Dyer, Gerald E. (Inventor)

    1989-01-01

    A welding torch for gas tungsten arc welding apparatus has a filler metal wire guide positioned within the torch, and within the shielding gas nozzle. The wire guide is adjacent to the tungsten electrode and has a ceramic liner through which the wire is fed. This reduces the size of the torch and eliminates the outside clearance problems that exit with external wire guides. Additionally, since the wire is always within the shielding gas, oxidizing of the wire is eliminated.

  9. Electrode carrying wire for GTAW welding

    NASA Technical Reports Server (NTRS)

    Morgan, Gene E. (Inventor); Dyer, Gerald E. (Inventor)

    1990-01-01

    A welding torch for gas tungsten arc welding apparatus has a hollow tungsten electrode including a ceramic liner and forms the filler metal wire guide. The wire is fed through the tungsten electrode thereby reducing the size of the torch to eliminate clearance problems which exist with external wire guides. Since the wire is preheated from the tungsten more wire may be fed into the weld puddle, and the wire will not oxidize because it is always within the shielding gas.

  10. Nano-storage wires.

    PubMed

    Lee, Dong Jun; Kim, Eunji; Kim, Daesan; Park, Juhun; Hong, Seunghun

    2013-08-27

    We report the development of "nano-storage wires" (NSWs), which can store chemical species and release them at a desired moment via external electrical stimuli. Here, using the electrodeposition process through an anodized aluminum oxide template, we fabricated multisegmented nanowires composed of a polypyrrole segment containing adenosine triphosphate (ATP) molecules, a ferromagnetic nickel segment, and a conductive gold segment. Upon the application of a negative bias voltage, the NSWs released ATP molecules for the control of motor protein activities. Furthermore, NSWs can be printed onto various substrates including flexible or three-dimensional structured substrates by direct writing or magnetic manipulation strategies to build versatile chemical storage devices. Since our strategy provides a means to store and release chemical species in a controlled manner, it should open up various applications such as drug delivery systems and biochips for the controlled release of chemicals.

  11. Sintered wire cathode

    DOEpatents

    Falce, Louis R.; Ives, R. Lawrence

    2009-06-09

    A porous cathode structure is fabricated from a plurality of wires which are placed in proximity to each other in elevated temperature and pressure for a sintering time. The sintering process produces the porous cathode structure which may be divided into a plurality of individual porous cathodes, one of which may be placed into a dispenser cathode support which includes a cavity for containing a work function reduction material such as BaO, CaO, and Al.sub.2O.sub.3. The work function reduction material migrates through the pores of the porous cathode from a work replenishment surface adjacent to the cavity of the dispenser cathode support to an emitting cathode surface, thereby providing a dispenser cathode which has a uniform work function and therefore a uniform electron emission.

  12. Plasma chemistry in wire chambers

    SciTech Connect

    Wise, J.

    1990-05-01

    The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an {sup 55}Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested except those containing methane, use of hygroscopic filters to remove trace water and oxygen contaminants from the gas resulted in an increase in the average molecular weight of the products, consistent with results from low-pressure rf-discharge plasmas. It is suggested that because water and oxygen inhibit polymer growth in the gas phase that they may also reduce polymer deposition in proportional tubes and therefore retard wire aging processes. Mechanistic implications of the plasma reactions of hydrocarbons with oxygen are suggested. Unresolved issues in this work and proposals for further study are discussed.

  13. Hot Meetings

    NASA Technical Reports Server (NTRS)

    Chiu, Mary

    2002-01-01

    A colleague walked by my office one time as I was conducting a meeting. There were about five or six members of my team present. The colleague, a man who had been with our institution (The Johns Hopkins Applied Physics Lab, a.k.a. APL) for many years, could not help eavesdropping. He said later it sounded like we we re having a raucous argument, and he wondered whether he should stand by the door in case things got out of hand and someone threw a punch. Our Advanced Composition Explorer (ACE) team was a hot group, to invoke the language that is fashionable today, although we never thought of ourselves in those terms. It was just our modus operandi. The tenor of the discussion got loud and volatile at times, but I prefer to think of it as animated, robust, or just plain collaborative. Mary Chiu and her "hot" team from the Johns Hopkins Applied Physics Laboratory built the Advanced Composition Explorer spacecraft for NASA. Instruments on the spacecraft continue to collect data that inform us about what's happening on our most important star, the Sun.

  14. Velocity and flow angle measurements in the Langley 0.3-meter transonic cryogenic tunnel using a laser transit anemometer

    NASA Technical Reports Server (NTRS)

    Honaker, W. C.

    1982-01-01

    The Laser Transit Anemometer (LTA) system is described. In the LTA system two parallel laser beams of known separation and cross sectional area are focussed at the same location or plane. When a particle in a flow field passes through both beams and the time is recorded for its transit (time of flight), its velocity can be calculated knowing the distance between the beams. By rotating the two beams (spots) around a common center and recording the number of valid events (a particle which passes through both spots in the proper sequence) at each angle the flow angle can be determined by curve fitting a predetermined number of angles or points and calculating the peak of what should be a Gaussian curve. The best angle or flow angle is defined as the angle at which the maximum number of valid events occurs. The LTA system functioned properly although conditions were less than desirable.

  15. The measurement of sperm motility by the fibre optic Doppler anemometer as a prediction of bovine fertility

    NASA Astrophysics Data System (ADS)

    Bullock, J. G.; Ross, D. A.

    The fibre optic Doppler anemometer (FODA) has been used to develop an accurate quantitative method of routinely assessing bull fertility. This method is of importance to the artificial insemination industry because the present qualitative estimation, performed by viewing semen using a microscope, can only set broad limits of quality. Laser light from the FODA was directed into diluted semen samples and the back scattered light was measured. A digital correlator was used to calculate the signal correlation of the back scattered light. The resultant data curves were interpreted in terms of the collective motility and swimming speed of the spermatozoa using a microcomputer. These two parameters are accepted as being indicative of fertility. The accuracy of this method is demonstrated by examination of results obtained in an experiment where enzymes, thought to alter fertility, were added to semen. The effect of the enzymes on the swimming speed and motility was clearly demonstrated.

  16. Demonstrating Forces between Parallel Wires.

    ERIC Educational Resources Information Center

    Baker, Blane

    2000-01-01

    Describes a physics demonstration that dramatically illustrates the mutual repulsion (attraction) between parallel conductors using insulated copper wire, wooden dowels, a high direct current power supply, electrical tape, and an overhead projector. (WRM)

  17. Wire Jewelry/Black History.

    ERIC Educational Resources Information Center

    Daniel, Robert A.; Robinson, Charles C.

    1984-01-01

    Described is a project which made the study of Black history more real to fifth graders by having them make wire jewelry, smaller versions of the ornate filigreed ironwork produced by slave blacksmiths. (RM)

  18. Spring control of wire harness loops

    NASA Technical Reports Server (NTRS)

    Curcio, P. J.

    1979-01-01

    Negator spring control guides wire harness between movable and fixed structure. It prevents electrical wire harness loop from jamming or being severed as wire moves in response to changes in position of aircraft rudder. Spring-loaded coiled cable controls wire loop regardless of rudder movement.

  19. Smart Wire Grid: Resisting Expectations

    ScienceCinema

    Ramsay, Stewart; Lowe, DeJim

    2016-07-12

    Smart Wire Grid's DSR technology (Discrete Series Reactor) can be quickly deployed on electrical transmission lines to create intelligent mesh networks capable of quickly rerouting electricity to get power where and when it's needed the most. With their recent ARPA-E funding, Smart Wire Grid has been able to move from prototype and field testing to building out a US manufacturing operation in just under a year.

  20. Smart Wire Grid: Resisting Expectations

    SciTech Connect

    Ramsay, Stewart; Lowe, DeJim

    2014-03-03

    Smart Wire Grid's DSR technology (Discrete Series Reactor) can be quickly deployed on electrical transmission lines to create intelligent mesh networks capable of quickly rerouting electricity to get power where and when it's needed the most. With their recent ARPA-E funding, Smart Wire Grid has been able to move from prototype and field testing to building out a US manufacturing operation in just under a year.

  1. 1 mil gold bond wire study.

    SciTech Connect

    Huff, Johnathon; McLean, Michael B.; Jenkins, Mark W.; Rutherford, Brian Milne

    2013-05-01

    In microcircuit fabrication, the diameter and length of a bond wire have been shown to both affect the current versus fusing time ratio of a bond wire as well as the gap length of the fused wire. This study investigated the impact of current level on the time-to-open and gap length of 1 mil by 60 mil gold bond wires. During the experiments, constant current was provided for a control set of bond wires for 250ms, 410ms and until the wire fused; non-destructively pull-tested wires for 250ms; and notched wires. The key findings were that as the current increases, the gap length increases and 73% of the bond wires will fuse at 1.8A, and 100% of the wires fuse at 1.9A within 60ms. Due to the limited scope of experiments and limited data analyzed, further investigation is encouraged to confirm these observations.

  2. HTS Wire Development Workshop: Proceedings

    SciTech Connect

    Not Available

    1994-07-01

    The 1994 High-Temperature Superconducting Wire Development Workshop was held on February 16--17 at the St. Petersburg Hilton and Towers in St. Petersburg, Florida. The meeting was hosted by Florida Power Corporation and sponsored by the US Department of Energy`s Superconductivity Program for Electric Power Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. The meeting opened with a general discussion on the needs and benefits of superconductivity from a utility perspective, the US global competitiveness position, and an outlook on the overall prospects of wire development. The meeting then focused on four important technology areas: Wire characterization: issues and needs; technology for overcoming barriers: weak links and flux pinning; manufacturing issues for long wire lengths; and physical properties of HTS coils. Following in-depth presentations, working groups were formed in each technology area to discuss the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.

  3. Asbestos and Inconel combined to form hot-gas seal

    NASA Technical Reports Server (NTRS)

    Wooster, C. W., Jr.

    1968-01-01

    Hot-gas seal prevents warpage tendencies in large flange joints exposed to high temperatures, such as those present in large space vehicle engine exhausts. Two Inconel wire mesh cores are held in place by an asbestos cloth cover that acts as a spacer to form the seal.

  4. An integrated temperature-compensated flexible shear-stress sensor microarray with concentrated leading-wire

    NASA Astrophysics Data System (ADS)

    Tang, Jian; Liu, Wu; Zhang, Weiping; Sun, Yongming; Chen, Honghai

    2016-02-01

    Flexible shear stress sensor is quite important for characterizing curved surface flows. In this work, a novel integrated shear stress sensor microarray is designed with twenty parallel channels, which share the concentrated leading-wire to transmit the ground signal. Electrical pads in rows are easily connected to the circuits with two separate Wheatstone bridges and constant-temperature-difference mode operation is provided for the hot-wires. Temperature crosstalk between adjacent hot-wires is prevented well and the effectiveness of the temperature compensated circuits is verified. Relatively large output response is obtained as the shear stress varies and the sensitivity of the sensors is measured about 0.086 V2/Pa1/3 with nonlinearity lower than 1%, revealing high performance characteristic of the sensors.

  5. An integrated temperature-compensated flexible shear-stress sensor microarray with concentrated leading-wire.

    PubMed

    Tang, Jian; Liu, Wu; Zhang, Weiping; Sun, Yongming; Chen, Honghai

    2016-02-01

    Flexible shear stress sensor is quite important for characterizing curved surface flows. In this work, a novel integrated shear stress sensor microarray is designed with twenty parallel channels, which share the concentrated leading-wire to transmit the ground signal. Electrical pads in rows are easily connected to the circuits with two separate Wheatstone bridges and constant-temperature-difference mode operation is provided for the hot-wires. Temperature crosstalk between adjacent hot-wires is prevented well and the effectiveness of the temperature compensated circuits is verified. Relatively large output response is obtained as the shear stress varies and the sensitivity of the sensors is measured about 0.086 V(2)/Pa(1/3) with nonlinearity lower than 1%, revealing high performance characteristic of the sensors. PMID:26931882

  6. Experimental Results for Space-Wire-D

    NASA Astrophysics Data System (ADS)

    Parkes, Steve; Gibson, David; Ferrer, Albert

    2015-09-01

    SpaceWire-D is a deterministic extension to SpaceWire that uses time-division multiplexing to schedule traffic within time-slots. It allows a single SpaceWire network to be used for both time-critical avionics control applications and asynchronous payload data-handling simultaneously using existing SpaceWire technology. In this paper we describe the services of SpaceWire-D and present experimental results for each service.

  7. Fabrication of Pd-Cr wire

    NASA Technical Reports Server (NTRS)

    Diamond, Sidney; Leach, Dennen M.

    1989-01-01

    Fabrication of Pd-13 percent Cr alloy wires is described. Melting, casting, swaging and annealing processes are discussed. Drawing to reach two diameters (0.003 inch and 0.00176 inch) of wire is described. Representative micrographs of the Pd-Cr alloy at selected stages during wire fabrication are included. The resistance of the wire was somewhat lower, by about 15 to 20 percent, than comparable wire of other alloys used for strain gages.

  8. Connecting to Thermocouples with Fewer Lead Wires

    NASA Technical Reports Server (NTRS)

    Goldsby, Jon C.

    2003-01-01

    A simple technique has been devised to reduce the number of lead wires needed to connect an array of thermocouples to the instruments (e.g., voltmeters) used to read their output voltages. Because thermocouple wires are usually made of expensive metal alloys, reducing the number of lead wires can effect a considerable reduction in the cost of such an array. Reducing the number of wires also reduces the number of terminals and the amount of space needed to accommodate the wires.

  9. Radioactive hot cell access hole decontamination machine

    DOEpatents

    Simpson, William E.

    1982-01-01

    Radioactive hot cell access hole decontamination machine. A mobile housing has an opening large enough to encircle the access hole and has a shielding door, with a door opening and closing mechanism, for uncovering and covering the opening. The housing contains a shaft which has an apparatus for rotating the shaft and a device for independently translating the shaft from the housing through the opening and access hole into the hot cell chamber. A properly sized cylindrical pig containing wire brushes and cloth or other disks, with an arrangement for releasably attaching it to the end of the shaft, circumferentially cleans the access hole wall of radioactive contamination and thereafter detaches from the shaft to fall into the hot cell chamber.

  10. Plasma arc torch with coaxial wire feed

    DOEpatents

    Hooper, Frederick M

    2002-01-01

    A plasma arc welding apparatus having a coaxial wire feed. The apparatus includes a plasma arc welding torch, a wire guide disposed coaxially inside of the plasma arc welding torch, and a hollow non-consumable electrode. The coaxial wire guide feeds non-electrified filler wire through the tip of the hollow non-consumable electrode during plasma arc welding. Non-electrified filler wires as small as 0.010 inches can be used. This invention allows precision control of the positioning and feeding of the filler wire during plasma arc welding. Since the non-electrified filler wire is fed coaxially through the center of the plasma arc torch's electrode and nozzle, the wire is automatically aimed at the optimum point in the weld zone. Therefore, there is no need for additional equipment to position and feed the filler wire from the side before or during welding.

  11. Californium Recovery from Palladium Wire

    SciTech Connect

    Burns, Jon D.

    2014-08-01

    The recovery of 252Cf from palladium-252Cf cermet wires was investigated to determine the feasibility of implementing it into the cermet wire production operation at Oak Ridge National Laboratory’s Radiochemical Engineering Development Center. The dissolution of Pd wire in 8 M HNO3 and trace amounts of HCl was studied at both ambient and elevated temperatures. These studies showed that it took days to dissolve the wire at ambient temperature and only 2 hours at 60°C. Adjusting the ratio of the volume of solvent to the mass of the wire segment showed little change in the kinetics of dissolution, which ranged from 0.176 mL/mg down to 0.019 mL/mg. A successful chromatographic separation of 153Gd, a surrogate for 252Cf, from Pd was demonstrated using AG 50x8 cation exchange resin with a bed volume of 0.5 mL and an internal diameter of 0.8 cm.

  12. Study of micro-pinches in wire-array Z pinches

    SciTech Connect

    Ivanov, V. V.; Papp, D.; Anderson, A. A.; Talbot, B. R.; Astanovitskiy, A. L.; Nalajala, V.; Dmitriev, O.; Chittenden, J. P.; Niasse, N.; Pikuz, S. A.; Shelkovenko, T. A.

    2013-11-15

    Bright and hot areas with a high plasma density and temperature are observed in all kinds of Z pinches. We studied bright radiating spots produced by micro-pinches in cylindrical and planar wire-arrays at the 1 MA Zebra pulsed power generator using an x-ray streak camera synchronized with laser diagnostics, x-ray time-gated pinhole camera, and spectroscopy. Hot spots with extremely dense and relatively hot plasma arise during the collapse of the micro-pinches. These hot spots radiate a continuum spectrum with energy >2.5 keV. Typical micro-pinches in Al wire arrays generate x-ray bursts with durations of 0.4–1 ns in the soft x-ray range and 0.1–0.4 ns in the keV range. UV two-frame shadowgraphy shows spatial correlation of hot spots with the collapse and explosion of micro-pinches. Micro-pinches typically occur at the necks of the Z pinch, but can demonstrate a variety of parameters and different dynamics. An analysis of x-ray streak images shows that micro-pinches can generate >20% of the x-ray energy in some types of wire-array Z pinches.

  13. Effects of hot and cold foods on signals of heart rate variability and nail fold microcirculation of healthy young humans: a pilot study.

    PubMed

    Chao, Dan-Ping; Chen, Jian-Jung; Huang, Sung-Yen; Tyan, Chu-Chang; Hsieh, Ching-Liang; Sheen, Lee-Yan

    2011-06-30

    In traditional Chinese medicine, hot- and cold-attribute of food ingredients are a major part of dietary therapy. The aim of this study was to establish a suitable scientific methodology to define the attributes of food ingredients by investigating the relationship between food attributes and the physiological signals produced in healthy young subjects with different constitutions. Thirty subjects were grouped into hot and cold constitutions by Chinese medical doctors. Every subject took water, aged ginger tea and coconut water, which are well recognized as having neutral-, hot- and cold-attribute, respectively, on different visits. The different physiological signals induced by the samples were observed using skin and axillary temperature sensors, a heart rate variability analyzer and a laser Doppler anemometer. We found that the capillary red blood cell (RBC) velocity in nail fold microcirculation (NFM) of the subjects with hot constitution accelerated significantly after taking the hot-attribute aged ginger tea, which might be the result of elevated vagal activity leading to arteriole dilation in these subjects. In contrast, in subjects with cold constitution, capillary RBC velocity decelerated significantly and skin temperature decreased markedly after taking the cold-attribute coconut water, which might have been induced by sympathetic nerve activation causing the arteriole to be constricted. Accordingly, the use of capillary RBC velocity of NFM measured by laser Doppler anemometer may be a promising way to classify attributes of food ingredients commonly used in Chinese medicine dietary therapy in accordance with different personal constitutions.

  14. Are hot Neptunes partially evaporated hot Jupiters?

    NASA Astrophysics Data System (ADS)

    Boué, G.; Figueira, P.; Correia, A. C. M.; Santos, N. C.

    2011-10-01

    The detection of short period planets (hot Jupiters and their lower mass counterparts, hot Neptunes and super-Earths) still defies the models of planet formation and evolution. Several possibilities have been proposed to explain the nature and formation process of the lower mass population, including in situ formation, disk migration, planet-planet scattering and kozai evolution, and the evaporation of a higher mass hot Jupiter. Using dynamical models and the best estimates for evaporation velocities, we show that under reasonable (and observed) physical conditions, hot Jupiter evaporation may explain the observed population of hot Neptunes/super-Earths.

  15. Are Hot Neptunes Partialy Evaporated Hot Jupiters?

    NASA Astrophysics Data System (ADS)

    Santos, Nuno; Boue, G.; Figueira, P.; Correia, A.

    2011-09-01

    The detection of short period planets (hot Jupiters and their lower mass counterparts, hot neptunes and super-earths) still defies the models of planet formation and evolution. Several possibilities have been proposed to explain the nature and formation process of the lower mass population, including in situ formation, disk migration, planet-planet scattering and kozai evolution, and the evaporation of a higher mass hot Jupiter. Using dynamical models and the best estimates for evaporation velocities, we show that under reasonable (and observed) physical conditions, hot Jupiter evaporation can explain the observed population of hot Neptunes/super-Earths.

  16. Uncertainties in wind speed dependent CO2 transfer velocities due to airflow distortion at anemometer sites on ships

    NASA Astrophysics Data System (ADS)

    Griessbaum, F.; Moat, B. I.; Narita, Y.; Yelland, M. J.; Klemm, O.; Uematsu, M.

    2010-06-01

    Data from platforms, research vessels and merchant ships are used to estimate ocean CO2 uptake via parameterisations of the gas transfer velocity (k) and measurements of the difference between the partial pressures of CO2 in the ocean (pCO2 sw) and atmosphere (pCO2 atm) and of wind speed. Gas transfer velocities estimated using wind speed dependent parameterisations may be in error due to air flow distortion by the ship's hull and superstructure introducing biases into the measured wind speed. The effect of airflow distortion on estimates of the transfer velocity was examined by modelling the airflow around the three-dimensional geometries of the research vessels Hakuho Maru and Mirai, using the Large Eddy Simulation code GERRIS. For airflows within ±45° of the bow the maximum bias was +16%. For wind speed of 10 m s-1 to 15 m s-1, a +16% bias in wind speed would cause an overestimate in the calculated value of k of 30% to 50%, depending on which k parameterisation is used. This is due to the propagation of errors when using quadratic or cubic parameterisations. Recommendations for suitable anemometer locations on research vessels are given. The errors in transfer velocity may be much larger for typical merchant ships, as the anemometers are generally not as well-exposed as those on research vessels. Flow distortion may also introduce biases in the wind speed dependent k parameterisations themselves, since these are obtained by relating measurements of the CO2 flux to measurements of the wind speed and the CO2 concentration difference. To investigate this, flow distortion effects were estimated for three different platforms from which wind speed dependent parameterisations are published. The estimates ranged from -4% to +14% and showed that flow distortion may have a significant impact on wind speed dependent parameterisations. However, the wind biases are not large enough to explain the differences at high wind speeds in parameterisations which are based on eddy

  17. Uncertainties in wind speed dependent CO2 transfer velocities due to airflow distortion at anemometer sites on ships

    NASA Astrophysics Data System (ADS)

    Griessbaum, F.; Moat, B. I.; Narita, Y.; Yelland, M. J.; Klemm, O.; Uematsu, M.

    2009-09-01

    Data from research vessels and merchant ships are used to estimate ocean CO2 uptake via parameterizations of the gas transfer velocity (k) and measurements of the difference between the concentration of CO2 in the ocean (pCO2sw) and atmosphere (pCO2atm) and of wind speed. Gas transfer velocities estimated using wind speed dependent parameterisations may be in error due to air flow distortion by the ship's hull and superstructure introducing biases into the measured wind speed. The effect of airflow distortion on estimates of the transfer velocity was examined by modelling the airflow around the three-dimensional geometries of the research vessels Hakuho Maru and Mirai, using the Large Eddy Simulation code GERRIS. For airflows within ±45° of the bow the maximum bias was +16%. For wind speed of 10 m s-1 to 15 m s-1, a +16% bias in wind speed would cause an overestimate in the calculated value of k of 30% to 50%, depending on which k parameterisation is used. This is due to the propagation of errors when using quadratic or cubic parameterizations. Recommendations for suitable anemometer locations on research vessels are given. The errors in transfer velocity may be much larger for typical merchant ships, as the anemometers are generally not as well-exposed as those on research vessels. Flow distortion may also introduce biases in the wind speed dependent k parameterizations themselves, since these are obtained by relating measurements of the CO2 flux to measurements of the wind speed and the CO2 concentration difference. To investigate this, flow distortion effects were estimated for three different platforms from which wind speed dependent parameterizations are published. The estimates ranged from -4% to +14% and showed that flow distortion may have a significant impact on wind speed dependent parameterizations. However, the wind biases are not large enough to explain the differences at high wind speeds in parameterizations which are based on eddy covariance and

  18. Wire Detection Algorithms for Navigation

    NASA Technical Reports Server (NTRS)

    Kasturi, Rangachar; Camps, Octavia I.

    2002-01-01

    In this research we addressed the problem of obstacle detection for low altitude rotorcraft flight. In particular, the problem of detecting thin wires in the presence of image clutter and noise was studied. Wires present a serious hazard to rotorcrafts. Since they are very thin, their detection early enough so that the pilot has enough time to take evasive action is difficult, as their images can be less than one or two pixels wide. Two approaches were explored for this purpose. The first approach involved a technique for sub-pixel edge detection and subsequent post processing, in order to reduce the false alarms. After reviewing the line detection literature, an algorithm for sub-pixel edge detection proposed by Steger was identified as having good potential to solve the considered task. The algorithm was tested using a set of images synthetically generated by combining real outdoor images with computer generated wire images. The performance of the algorithm was evaluated both, at the pixel and the wire levels. It was observed that the algorithm performs well, provided that the wires are not too thin (or distant) and that some post processing is performed to remove false alarms due to clutter. The second approach involved the use of an example-based learning scheme namely, Support Vector Machines. The purpose of this approach was to explore the feasibility of an example-based learning based approach for the task of detecting wires from their images. Support Vector Machines (SVMs) have emerged as a promising pattern classification tool and have been used in various applications. It was found that this approach is not suitable for very thin wires and of course, not suitable at all for sub-pixel thick wires. High dimensionality of the data as such does not present a major problem for SVMs. However it is desirable to have a large number of training examples especially for high dimensional data. The main difficulty in using SVMs (or any other example-based learning

  19. Designing potentials by sculpturing wires

    SciTech Connect

    Della Pietra, Leonardo; Aigner, Simon; Groth, Soenke; Hagen, Christoph von; Schmiedmayer, Joerg; Bar-Joseph, Israel; Lezec, Henri J.

    2007-06-15

    Magnetic trapping potentials for atoms on atom chips are determined by the current flow in the chip wires. By modifying the shape of the conductor we can realize specialized current flow patterns and therefore microdesign the trapping potentials. We have demonstrated this by nano-machining an atom chip using the focused ion beam technique. We built a trap, a barrier, and using a Bose-Einstein Condensate as a probe we showed that by polishing the conductor edge the potential roughness on the selected wire can be reduced. Furthermore, we give different other designs and discuss the creation of a one-dimensional magnetic lattice on an atom chip.

  20. Heating in short-pulse laser-driven cone-capped wire targets

    NASA Astrophysics Data System (ADS)

    Mason, R. J.; Wei, M.; King, J.; Beg, F.; Stephens, R. B.

    2007-11-01

    The 2-D implicit hybrid simulation code e-PLAS has been used to study heating in cone-capped copper wire targets. The code e-PLAS tracks collisional particle-in-cell (PIC) electrons traversing background plasma of collisional Eulerian cold electron and ion fluids. It computes E- and B-fields by the Implicit Moment Method [1,2]. In recent experiments [3] at the Vulcan laser facility, sub- picosecond laser pulses at 1.06 μm, and 4.0 x 10^20 W/cm^2 intensity were focused into thin-walled (˜10 μm) cones attached to copper wires. The wire diameter was varied from 10-40 μm with a typical length of 1 mm. We characterize heating of the wires as a function of their diameters and length, and relate modifications of this heating to changes in the assumed laser-generated hot electron spectrum and directivity. As in recent nail experiments [4], the cones can serve as reservoirs for hot electrons, diverting them from passage down the wires. [1] R. J. Mason, and C. Cranfill, IEEE Trans. Plasma Sci. PS-14, 45 (1986). [2] R. J. Mason, J. Comp. Phys. 71, 429 (1987). [3] J. King et al., to be submitted to Phys. Rev. Lett.. [4] R. J. Mason, M. Wei, F. Beg, R. Stephens, and C. Snell, in Proc. of ICOPS07, Albuquerque, NM, June 17-22, 2007, Talk 7D4.

  1. 30 CFR 57.12047 - Guy wires.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Underground § 57.12047 Guy wires. Guy wires of poles supporting high-voltage transmission lines shall meet the... “Safety Rules for the Installation and Maintenance of Electric Supply and Communication Lines”...

  2. Anode wire aging tests with selected gases

    SciTech Connect

    Kadyk, J.; Wise, J.; Hess, D.; Williams, M. )

    1990-04-01

    As a continuation of earlier wire aging investigations, additional candidates for wire chamber gas and wire have been tested. These include the gases: argon/ethane, HRS gas, dimethyl ether, carbon dioxide/ethane, and carbon tetrafluoride/isobutane. Wires used were: gold- plated tungsten, Stablohm, Nicotin, and Stainless Steel. Measurements were made of the effects upon wire aging of impurities from plumbing materials or contamination from various types of oil. Attempts were made to induce wire aging by adding measured amounts of oxygen and halogen (methyl chloride) with negative results. In this paper, the possible role of electronegativity in the wire aging process is discussed, and measurements of electronegativity are made with several single carbon Freons, using both an electron capture detector and a wire chamber operating with dimethyl ether.

  3. Wire Capture Programs for Macintosh and IBM.

    ERIC Educational Resources Information Center

    Wiley, Gale

    1989-01-01

    Discusses wire capture programs (computer programs which gather and process wire services such as the Associated Press or United Press) for computer labs in journalism departments. Describes details of such programs for Macintosh, IBM, and IBM clones. (SR)

  4. 49 CFR 393.28 - Wiring systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    .... Electrical wiring shall be installed and maintained to conform to SAE J1292—Automobile, Truck, Truck-Tractor, Trailer, and Motor Coach Wiring, October 1981, except the jumper cable plug and receptacle need...

  5. 49 CFR 393.28 - Wiring systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... Electrical wiring shall be installed and maintained to conform to SAE J1292—Automobile, Truck, Truck-Tractor, Trailer, and Motor Coach Wiring, October 1981, except the jumper cable plug and receptacle need...

  6. 49 CFR 393.28 - Wiring systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .... Electrical wiring shall be installed and maintained to conform to SAE J1292—Automobile, Truck, Truck-Tractor, Trailer, and Motor Coach Wiring, October 1981, except the jumper cable plug and receptacle need...

  7. 49 CFR 393.28 - Wiring systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    .... Electrical wiring shall be installed and maintained to conform to SAE J1292—Automobile, Truck, Truck-Tractor, Trailer, and Motor Coach Wiring, October 1981, except the jumper cable plug and receptacle need...

  8. Put Your Cable Wiring to the Test.

    ERIC Educational Resources Information Center

    Day, C. William

    2001-01-01

    Discusses why schools and universities should use testing procedures in any wire bid specification for cable wiring and also know how experienced the installers are in testing and installing structured cabling systems. Key cabling terms are included. (GR)

  9. Electrical wire insulation and electromagnetic coil

    DOEpatents

    Bich, George J.; Gupta, Tapan K.

    1984-01-01

    An electromagnetic coil for high temperature and high radiation application in which glass is used to insulate the electrical wire. A process for applying the insulation to the wire is disclosed which results in improved insulation properties.

  10. New insulation constructions for aerospace wiring applications

    NASA Technical Reports Server (NTRS)

    Slenski, George

    1994-01-01

    Outlined in this presentation is the background to insulation constructions for aerospace wiring applications, the Air Force wiring policy, the purpose and contract requirements of new insulation constructions, the test plan, and the test results.

  11. Technique for stripping Teflon insulated wire

    NASA Technical Reports Server (NTRS)

    Babb, B. D.

    1967-01-01

    Cryogenic stripping of Teflon insulated wire leaves no residue and produces no physical damage. After the wire is immersed in liquid nitrogen, bent slightly, and returned to room temperature, the Teflon is removed by fingernails or flat-nosed pliers.

  12. Three Dimensional Wind Speed and Flux Measurement over a Rain-fed Soybean Field Using Orthogonal and Non-orthogonal Sonic Anemometer Designs

    NASA Astrophysics Data System (ADS)

    Thomas, T.; Suyker, A.; Burba, G. G.; Billesbach, D.

    2014-12-01

    The eddy covariance method for estimating fluxes of trace gases, energy and momentum in the constant flux layer above a plant canopy fundamentally relies on accurate measurements of the vertical wind speed. This wind speed is typically measured using a three dimensional ultrasonic anemometer. These anemometers incorporate designs with transducer sets that are aligned either orthogonally or non-orthogonally. Previous studies comparing the two designs suggest differences in measured 3D wind speed components, in particular vertical wind speed, from the non-orthogonal transducer relative to the orthogonal design. These differences, attributed to additional flow distortion caused by the non-orthogonal transducer arrangement, directly affect fluxes of trace gases, energy and momentum. A field experiment is being conducted over a rain-fed soybean field at the AmeriFlux site (US-Ne3) near Mead, Nebraska. In this study, ultrasonic anemometers featuring orthogonal transducer sets (ATI Vx Probe) and non-orthogonal transducer sets (Gill R3-100) collect high frequency wind vector and sonic temperature data. Sensible heat and momentum fluxes and other key sonic performance data are evaluated based on environmental parameters including wind speed, wind direction, temperature, and angle of attack. Preliminary field experiment results are presented.

  13. Measurements of Flow Distortion within the IRGASON Integrated Sonic Anemometer and CO_2/H_2O Gas Analyzer

    NASA Astrophysics Data System (ADS)

    Horst, T. W.; Vogt, R.; Oncley, S. P.

    2016-07-01

    Wind-tunnel and field measurements are analyzed to investigate flow distortion within the IRGASON integrated sonic anemometer and CO_2/H_2O gas analyzer as a function of wind speed, wind direction and attack angle. The wind-tunnel measurements are complimentary to the field measurements, and the dependence of the wind-tunnel mean-wind-component flow-distortion errors on wind direction agrees well with that of the field measurements. The field measurements exhibit significant overestimation of the crosswind variance and underestimation of the momentum flux with respect to an adjacent CSAT3 sonic, as well as a transfer of turbulent kinetic energy from the streamwise wind component to the cross-stream wind components. In contrast, we find attenuation of only a few percent in the vertical velocity variance and the vertical flux of sonic temperature. The attenuation of the fluxes appears to be caused to a large extent by decorrelation between the horizontal and vertical-velocity components and between the vertical velocity and sonic temperature. Additional flow distortion due to transducer shadowing reduces to some extent the overestimation, but also increases the underestimation of the IRGASON turbulence statistics.

  14. Laser transit anemometer and Pitot probe comparative measurements in a sharp cone boundary layer at Mach 4

    NASA Technical Reports Server (NTRS)

    Hunter, W. W., Jr.; Ocheltree, S. L.; Russ, C. E., Jr.

    1991-01-01

    Laser transit anemometer (LTA) measurements of a 7 degree sharp cone boundary layer were conducted in the Air Force/AEDC Supersonic Tunnel A Mach 4 flow field. These measurements are compared with Pitot probe measurements and tricone theory provided by AEDC staff. Measurements were made both in laminar and turbulent boundary layers of the model. Comparison of LTA measurements with theory showed agreement to better than 1 percent for the laminar boundary layer cases. This level of agreement was obtained after small position corrections, 0.01 to 0.6 mm, were applied to the experimental data sets. Pitot probe data when compared with theory also showed small positioning errors. The Pitot data value was also limited due to probe interference with the flow near the model. The LTA turbulent boundary layer data indicated a power law dependence of 6.3 to 6.9. The LTA data was analyzed in the time (Tau) domain in which it was obtained and in the velocity domain. No significant differences were noted between Tau and velocity domain results except in one turbulent boundary layer case.

  15. An experimental investigation of throughflow velocities in two-dimensional fluidized bed bubbles: Laser Doppler anemometer measurements

    SciTech Connect

    Gautam, M. . Dept. of Mechanical and Aerospace Engineering); Jurewicz, J.T. ); Kale, S.R. . Dept. of Mechanical Engineering)

    1994-09-01

    Detailed nonintrusive measurements have been made to determine the throughflow velocity in isolated fluidized bed bubbles. In air-fluidized beds, the throughflow component has been rather neglected and measurements of the visible bubbleflow alone have, therefore, failed to clarify the overall distribution of gas flow between the phases. A single component fiber optic laser Doppler anemometer was used to map the fluid flow through a bubble rising in a two-dimensional bed. The bed was fluidized at a superficial velocity slightly than incipient. The conditioned sampling technique developed to characterize the periodic nature of the bubble phase flow revealed that the throughflow velocity in two-dimensional beds increases linearly with increasing distance from the distributor, thereby enhancing the convective component in the interphase mass transfer process. Bubble growth was accounted for and the end-effects were minimized. Dependence of the bubble throughflow on the elongation of the bubble was observed thus confirming the theoretical analysis of some previous investigators. However, experimental evidence presented in this paper showed that the existing models fail to accurately predict the convective component in the bubble phase of two-dimensional fluidized beds.

  16. Regeneration: New Neurons Wire Up.

    PubMed

    Raymond, Pamela A

    2016-09-12

    Functional repair of damage in the nervous system requires re-establishment of precise patterns of synaptic connectivity. A new study shows that after selective ablation, zebrafish retinal neurons regenerate and reconstruct some, although not all, of their stereotypic wiring. PMID:27623258

  17. Fabrication of tungsten wire needles

    SciTech Connect

    Roder, A.

    1983-02-01

    Fine point needles for field emissoin are conventionally produced by electrolytically or chemically etching tungsten wire. Points formed in this manner have a typical tip radius of about 0.5 microns and a cone angle of some 30 degrees. The construction of needle matrix detector chambers has created a need for tungsten needles whose specifications are: 20 mil tungsten wire, 1.5 inch total length, 3 mm-long taper (resulting in a cone angle of about 5 degrees), and 25 micron-radius point (similar to that found on sewing needles). In the process described here for producing such needles, tungsten wire, immersed in a NaOH solution and in the presence of an electrode, is connected first to an ac voltage and then to a dc supply, to form a taper and a point on the end of the wire immersed in the solution. The process parameters described here are for needles that will meet the above specifications. Possible variations will be discussed under each approprite heading.

  18. Ultrasonic Calibration Wire Test Phantom

    SciTech Connect

    Lehman, S K; Fisher, K A; Werve, M; Chambers, D H

    2004-09-24

    We designed and built a phantom consisting of vertical wires maintained under tension to be used as an ultrasonic test, calibration, and reconstruction object for the Lawrence Livermore National Laboratory annular array scanner. We provide a description of the phantom, present example data sets, preliminary reconstructions, example metadata, and MATLAB codes to read the data.

  19. Troubleshooting plated-wire memories

    NASA Technical Reports Server (NTRS)

    Baker, C. M.; Bright, T. M.; Constable, R. C.

    1979-01-01

    Faults in plated wire memories are identified and located from outside of system by applying electrical impulses and analyzing their reflectance in technique of Time-Domain Reflectometry (TDR). Intermittent faults are easier to find because memory system is not disturbed by probing or disassembly.

  20. Flexible substrate for printed wiring

    NASA Technical Reports Server (NTRS)

    Asakura, M.; Yabe, K.; Tanaka, H.; Soda, A.

    1982-01-01

    A very flexible substrate for printed wiring is disclosed which is composed of a blend of phenoxy resin-polyisocyanate-brominated epoxy resin in which the equivalent ration of the functional groups is hydroxyl grouped: isocyanate group: epoxy group = 1:0.2 to 2:0.5 to 3. The product has outstanding solder resistance and is applied to metal without using adhesives.

  1. Plated wire random access memories

    NASA Technical Reports Server (NTRS)

    Gouldin, L. D.

    1975-01-01

    A program was conducted to construct 4096-work by 18-bit random access, NDRO-plated wire memory units. The memory units were subjected to comprehensive functional and environmental tests at the end-item level to verify comformance with the specified requirements. A technical description of the unit is given, along with acceptance test data sheets.

  2. NEMA wire and cable standards development programs

    NASA Technical Reports Server (NTRS)

    Baird, Robert W.

    1994-01-01

    The National Electrical Manufacturers Association (NEMA) is the nation's largest trade association for manufacturers of electrical equipment. Its member companies produce components, end-use equipment and systems for the generation, transmission, distribution, control and use of electricity. The wire and cable division is presented in 6 sections: building wire and cable, fabricated conductors, flexible cords, high performance wire and cable, magnet wire, and power and control cable. Participating companies are listed.

  3. Novel Wiring Technologies for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Gibson, Tracy L.; Parrish, Lewis M.

    2014-01-01

    Because wire failure in aerospace vehicles could be catastrophic, smart wiring capabilities have been critical for NASA. Through the years, researchers at Kennedy Space Center (KSC) have developed technologies, expertise, and research facilities to meet this need. In addition to aerospace applications, NASA has applied its knowledge of smart wiring, including self-healing materials, to serve the aviation industry. This webinar will discuss the development efforts of several wiring technologies at KSC and provide insight into both current and future research objectives.

  4. Home and School Technology: Wired versus Wireless.

    ERIC Educational Resources Information Center

    Van Horn, Royal

    2001-01-01

    Presents results of informal research on smart homes and appliances, structured home wiring, whole-house audio/video distribution, hybrid cable, and wireless networks. Computer network wiring is tricky to install unless all-in-one jacketed cable is used. Wireless phones help installers avoid pre-wiring problems in homes and schools. (MLH)

  5. 49 CFR 236.838 - Wire, shunt.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Wire, shunt. 236.838 Section 236.838 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Wire, shunt. A wire forming part of a shunt circuit....

  6. Measurements and simulations of the ablation stage of wire arrays with different initial wire sizes

    SciTech Connect

    Sinars, D.B.; Cuneo, M.E.; Yu, E.P.; Jones, B.; Mehlhorn, T.A.; Porter, J.L.; Wenger, D.F.; Lebedev, S.V.; Cochrane, K.R.; MacFarlane, J.J.

    2006-04-15

    Comparisons of 20 mm diameter, 300-wire tungsten arrays with different initial wire sizes were made on the 20 MA Sandia Z facility. Radiographic measurements of each wire array, taken at the same point in the current during the wire ablation stage, show systematic differences. A detailed comparison of the radiography and self-emission data with simulations and analytic models suggests that a variation in the mass ablation rate with wire size may be responsible.

  7. Return current and proton emission from wire targets interacting with an intense short pulse laser

    NASA Astrophysics Data System (ADS)

    Beg, Farhat

    2004-05-01

    One of the important characteristics of short pulse high intensity laser-solid interactions is the generation of energetic charged particles, which result from the very efficient conversion of laser energy into hot electrons. Since the electrons in the electric field of the laser have relativistic quiver motions, the temperature of the hot electron distribution of the plasma produced at such extreme intensities can become very high. A large number of hot electrons (1013-1014) having an average energy of the order of 1-2 MeV can be generated as intensities exceed 1019 Wcm-2. Since the resulting beam current exceeds the Alfvén limit, a neutralizing return current of cold plasma electrons moving in the opposite direction is produced. Another source of return current is that due to the escape of very energetic electrons from the target, which then creates a large electrostatic potential due to charge separation. These return currents can cause significant ohmic heating. In addition escaping electrons establish the large electrostatic fields, accelerating a large number of protons from the target with energies of 10's of MeV. The experiments reported here were performed at the Rutherford Appleton Laboratory with the VULCAN laser facility at intensity greater than 5 x1019 Wcm-2 on wire targets. In some shots an additional wire or foil was placed nearby. The laser was blocked by the main wire target so that no laser light reached the additional wire or foil. Three main observations were made: (i) a Z-pinch was driven in the wire due to the return current, (ii) optical transition radiation (OTR) at 2w was generated and (iii) energetic proton emission was observed. The wire targets were observed to be ohmically heated and were m=0 unstable. The OTR emission is likely due to electron bunches accelerated by the ponderomotive force of the laser. The proton emission was in a form of thin disk perpendicular to the wire and centered on the wire at the laser focus. Proton

  8. Emittance growth due to Tevatron flying wires

    SciTech Connect

    Syphers, M; Eddy, Nathan

    2004-06-01

    During Tevatron injection, Flying Wires have been used to measure the transverse beam size after each transfer from the Main Injector in order to deduce the transverse emittances of the proton and antiproton beams. This amounts to 36 + 9 = 45 flies of each of 3 wire systems, with an individual wire passing through each beam bunch twice during a single ''fly''. below they estimate the emittance growth induced by the interaction of the wires with the particles during these measurements. Changes of emittance from Flying Wire measurements conducted during three recent stores are compared with the estimations.

  9. SpaceWire Data Handling Demonstration System

    NASA Astrophysics Data System (ADS)

    Mills, S.; Parkes, S. M.; O'Gribin, N.

    2007-08-01

    The SpaceWire standard was published in 2003 with the aim of providing a standard for onboard communications, defining the physical and data link layers of an interconnection, in order to improve reusability, reliability and to reduce the cost of mission development. The many benefits which it provides mean that it has already been used in a number of missions, both in Europe and throughout the world. Recent work by the SpaceWire community has included the development of higher level protocols for SpaceWire, such as the Remote Memory Access Protocol (RMAP) which can be used for many purposes, including the configuration of SpaceWire devices. Although SpaceWire has become very popular, the various ways in which it can be used are still being discovered, as are the most efficient ways to use it. At the same time, some in the space industry are not even aware of SpaceWire's existence. This paper describes the SpaceWire Data Handling Demonstration System that has been developed by the University of Dundee. This system simulates an onboard data handling network based on SpaceWire. It uses RMAP for all communication, and so demonstrates how SpaceWire and standardised higher level protocols can be used onboard a spacecraft. The system is not only a good advert for those who are unfamiliar with the benefits of SpaceWire, it is also a useful tool for those using SpaceWire to test ideas.

  10. Wavelength modulated SERS hot spot distribution in 1D nanostructures on metal film

    NASA Astrophysics Data System (ADS)

    Wang, Lili; Zeng, Xiping; Liu, Ting; Zhang, Xuemei; Wei, Hua; Huang, Yingzhou; Liu, Anping; Wang, Shuxia; Wen, Weijia

    2016-10-01

    Surface plasmons confining strong electromagnetic fields near metal surfaces, well-known as hot spots, provide an extremely efficient platform for surface-enhanced Raman scattering (SERS). In this work, SERS spectra of probing molecules in a silver particle-wire 1D nanostructure on a thin gold film are investigated. The Raman features of SERS spectra collected at the particle-wire joints exhibit an obvious wavelength dependence phenomenon. This result is confirmed electromagnetic field simulation, revealing that hot spot distribution is sensitively influenced by the wavelength of incident light at the joints. Further studies indicate this wavelength dependence of hot spot distribution is immune to influence from the geometric shape of the particle or the angle between wire and particle, which improves fabrication tolerance. This technology may have promising applications in surface plasmon related fields, such as ultrasensors, solar energy and selective surface catalysis.

  11. Wire Crimp Connectors Verification using Ultrasonic Inspection

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Perey, Daniel F.; Yost, William T.

    2007-01-01

    The development of a new ultrasonic measurement technique to quantitatively assess wire crimp connections is discussed. The amplitude change of a compressional ultrasonic wave propagating through the junction of a crimp connector and wire is shown to correlate with the results of a destructive pull test, which previously has been used to assess crimp wire junction quality. Various crimp junction pathologies (missing wire strands, incorrect wire gauge, incomplete wire insertion in connector) are ultrasonically tested, and their results are correlated with pull tests. Results show that the ultrasonic measurement technique consistently (as evidenced with pull-testing data) predicts good crimps when ultrasonic transmission is above a certain threshold amplitude level. A physics-based model, solved by finite element analysis, describes the compressional ultrasonic wave propagation through the junction during the crimping process. This model is in agreement within 6% of the ultrasonic measurements. A prototype instrument for applying the technique while wire crimps are installed is also presented.

  12. Composite wire plasma formation and evolution

    SciTech Connect

    Spielman, R.B.

    2000-01-01

    The detailed understanding of the formation and evolution of plasma from rapidly heated metallic wires is a long-standing challenge in the field of plasma physics and in exploding wire engineering. This physical process is made even more complicated if the wire material is composed of a number of individual layers. The authors have successfully developed both optical and x-ray backlighting diagnostics. In particular, the x-ray backlighting technique has demonstrated the capability for quantitative determination of the plasma density over a wide range of densities. This diagnostic capability shows that the process of plasma formation is composed of two separate phases: first, current is passed through a cold wire and the wire is heated ohmically, and, second, the heated wire evolves gases that break down and forms a low-density plasma surrounding the wire.

  13. NASA wiring for space applications program

    NASA Technical Reports Server (NTRS)

    Schulze, Norman

    1995-01-01

    An overview of the NASA Wiring for Space Applications Program and its relationship to NASA's space technology enterprise is given in viewgraph format. The mission of the space technology enterprise is to pioneer, with industry, the development and use of space technology to secure national economic competitiveness, promote industrial growth, and to support space missions. The objectives of the NASA Wiring for Space Applications Program is to improve the safety, performance, and reliability of wiring systems for space applications and to develop improved wiring technologies for NASA flight programs and commercial applications. Wiring system failures in space and commercial applications have shown the need for arc track resistant wiring constructions. A matrix of tests performed versus wiring constructions is presented. Preliminary data indicate the performance of the Tensolite and Filotex hybrid constructions are the best of the various candidates.

  14. Vibrating wire for beam profile scanning

    NASA Astrophysics Data System (ADS)

    Arutunian, S. G.; Dobrovolski, N. M.; Mailian, M. R.; Sinenko, I. G.; Vasiniuk, I. E.

    1999-12-01

    A method that measures the transverse profile (emittance) of the bunch by detecting radiation arising at the scattering of the bunch on scanning wire is widely used. In this work information about bunch scattering is obtained by measuring the oscillation frequency of the tightened scanning wire. In such a way, the system of radiation (or secondary particles) extraction and measurement can be removed. The entire unit consists of a compact fork with tightened wire and a scanning system. Normal oscillation frequency of a wire depends on wire tension, its geometric parameters, and, in a second approximation, its elastic characteristics. Normal oscillations are generated by interaction of an alternating current through the wire with magnetic field of a permanent magnet. In this case, it is suggested that the magnetic field of the accelerator (field of dipole magnets or quadrupole magnets) be used for excitation of oscillations. The dependence of oscillation frequency on beam scattering is determined by several factors, including changes of wire tension caused by transverse force of the beam and influence of beam self-field. Preliminary calculations show that the influence of wire heating will dominate. We have studied strain gauges on the basis of vibrating wire from various materials (tungsten, beryl bronze, and niobium zirconium alloys). A scheme of normal oscillation generation by alternating current in autogeneration circuit with automatic frequency adjustment was selected. A special method of wire fixation and elimination of transverse degrees of freedom allows us to achieve relative stability better than 10-5 during several days at a relative resolution of 10-6. Experimental results and estimates of wire heating of existing scanners show that the wire heats up to a few hundred grades, which is enough for measurements. The usage of wire of micrometer thickness diminishes the problem of wire thermalization speed during the scanning of the bunch.

  15. Sintered wire cesium dispenser photocathode

    SciTech Connect

    Montgomery, Eric J; Ives, R. Lawrence; Falce, Louis R

    2014-03-04

    A photoelectric cathode has a work function lowering material such as cesium placed into an enclosure which couples a thermal energy from a heater to the work function lowering material. The enclosure directs the work function lowering material in vapor form through a low diffusion layer, through a free space layer, and through a uniform porosity layer, one side of which also forms a photoelectric cathode surface. The low diffusion layer may be formed from sintered powdered metal, such as tungsten, and the uniform porosity layer may be formed from wires which are sintered together to form pores between the wires which are continuous from the a back surface to a front surface which is also the photoelectric surface.

  16. The transmaxillary K-wire.

    PubMed Central

    Silverton, J. S.; Bostwick, J.; Jurkiewicz, M. J.

    1978-01-01

    The transmaxillary K-wire is a simple, fast, safe, and effective technique for the fixation of unstable tractured malar bones. Combined with other techniques such as interdental fixation it simplifies and provides the fixation of the Le Fort II fracture or osteotomy and certain osteotomies used for facial advancement. The technique of insertion is described and illustrated. Images Fig. 4 Fig. 5 Fig. 6 PMID:666241

  17. Reduced-Wiring Tactile Sensor

    NASA Technical Reports Server (NTRS)

    Ohm, Timothy R.

    1991-01-01

    Proposed tactile sensor on robot finger puts out multiplexed analog signals transmitted to control computer on fewer wires than needed to transmit equivalent digital signals. Analog output represents data on contact area of object being gripped, on position of object, and on direction and rate of slippage if any. Consists of chains of normally open switches and resistors on surface of finger. Each resistance double preceding resistance in each chain. Constant-current sources supply power to chains.

  18. A comparison of a coaxial focused laser Doppler system in atmospheric measurements

    NASA Technical Reports Server (NTRS)

    Karaki, S.

    1973-01-01

    Measurements of atmospheric velocities and turbulence with the laser Doppler system were obtained, and the results compared with cup anemometer and hot-wire measurements in the same wind field. The laser Doppler velocimeter (LDV) is described along with the test procedures. It was found that mean values determined from the LDV data are within 5% of other anemometer data for long time periods, and the LDV measures higher velocities.

  19. 77 FR 17430 - Galvanized Steel Wire From the People's Republic of China: Final Determination of Sales at Less...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-26

    ... Determination, 76 FR 68407 (November 4, 2011) (``Preliminary Determination''). \\2\\ See Galvanized Steel Wire..., 76 FR 73589 (November 29, 2011) (``Amended Preliminary Determination''). FOR FURTHER INFORMATION... zinc (whether by hot-dipping or electroplating). Steel products to be included in the scope of...

  20. 76 FR 67672 - Certain Stainless Steel Wire Rods From India: Final Results of the Expedited Sunset Review of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-02

    ... Five-Year (``Sunset'') Review, 76 FR 38613 (July 1, 2011) (Notice of Initiation). The Department has...\\ Antidumping Duty Order: Certain Stainless Steel Wire Rods from India, 58 FR 63335 (December 1, 1993). The... chromium, with or without other elements. These products are only manufactured by hot-rolling and...

  1. Method and apparatus for laying wire arrays

    DOEpatents

    Horowitz, Seymour M.; Nesbitt, Dale D.

    1986-01-01

    Wire arrays (11) having a continuous wire (12) which is formed into a predetermined pattern and adhered to a backing material or substrate (13) are fabricated by applying adhesive material (16a, 16b) along opposite edge portions (17, 18) of the substrate, positioning a row of winding spools (21) along each of the edge portions and repeatedly extending the wire between and around successive spools at the opposite edge portions. The wound wire is then traveled along each spool toward the substrate and into contact with the adhesive. The spools are then removed and a coating of hardenable material (54) is applied to secure the wound wire to the substrate. Tension in the wire is relieved prior to contact of the wire with the adhesive and a small amount of slack is introduced into the wire before the final coating step. Mechanism (32) is provided for lifting the spools away from the substrate without disturbing the wound wire. The method and apparatus enable manufacture of precisely configured wire arrays without complex or costly equipment and do not require structural alterations in the substrate for the purpose of accommodating to fabrication equipment.

  2. Generation and characterization of warm dense matter isochorically heated by laser-induced relativistic electrons in a wire target

    NASA Astrophysics Data System (ADS)

    Schönlein, A.; Boutoux, G.; Pikuz, S.; Antonelli, L.; Batani, D.; Debayle, A.; Franz, A.; Giuffrida, L.; Honrubia, J. J.; Jacoby, J.; Khaghani, D.; Neumayer, P.; Rosmej, O. N.; Sakaki, T.; Santos, J. J.; Sauteray, A.

    2016-05-01

    We studied the interaction of a high-intensity laser with mass-limited Ti-wires. The laser was focused up to 7× 1020 \\text{W/cm}2 , with contrast of 10-10 to produce relativistic electrons. High-spatial-resolution X-ray spectroscopy was used to measure isochoric heating induced by hot electrons propagating along the wire up to 1 mm depth. For the first time it was possible to distinguish surface target regions heated by mixed plasma mechanisms from those heated only by the hot electrons that generate warm dense matter with temperatures up to 50 eV. Our results are compared to simulations that highlight both the role of electron confinement inside the wire and the importance of resistive stopping powers in warm dense matter.

  3. Analysis of Conical Wire Array Z-Pinch Stability with a Center Wire

    SciTech Connect

    Martinez, D.; Presura, R.; Wright, S.; Plechaty, C.; Neff, S.; Wanex, L.; Ampleford, D. J.

    2009-01-21

    Adding a center wire on the axis of a conical wire array produces conditions suitable for studying shear flow stabilization of the Z-pinch. The conical wire array produces and axial plasma flow while the center wire introduces a radial variation of the axial velocity. Experiments of this array configuration were preformed on the 1 MA Zebra Z-pinch generator and showed stabilization of the kink instability when a center wire was present. Comparison with equivalent cylindrical wire arrays indicates that the shear flow stabilization plays a role in the stabilization of the kink instability.

  4. A Vibrating Wire System For Quadrupole Fiducialization

    SciTech Connect

    Wolf, Zachary

    2010-12-13

    A vibrating wire system is being developed to fiducialize the quadrupoles between undulator segments in the LCLS. This note provides a detailed analysis of the system. The LCLS will have quadrupoles between the undulator segments to keep the electron beam focused. If the quadrupoles are not centered on the beam axis, the beam will receive transverse kicks, causing it to deviate from the undulator axis. Beam based alignment will be used to move the quadrupoles onto a straight line, but an initial, conventional alignment must place the quadrupole centers on a straight line to 100 {micro}m. In the fiducialization step of the initial alignment, the position of the center of the quadrupole is measured relative to tooling balls on the outside of the quadrupole. The alignment crews then use the tooling balls to place the magnet in the tunnel. The required error on the location of the quadrupole center relative to the tooling balls must be less than 25 {micro}m. In this note, we analyze a system under construction for the quadrupole fiducialization. The system uses the vibrating wire technique to position a wire onto the quadrupole magnetic axis. The wire position is then related to tooling balls using wire position detectors. The tooling balls on the wire position detectors are finally related to tooling balls on the quadrupole to perform the fiducialization. The total 25 {micro}m fiducialization error must be divided between these three steps. The wire must be positioned onto the quadrupole magnetic axis to within 10 {micro}m, the wire position must be measured relative to tooling balls on the wire position detectors to within 15 {micro}m, and tooling balls on the wire position detectors must be related to tooling balls on the quadrupole to within 10 {micro}m. The techniques used in these three steps will be discussed. The note begins by discussing various quadrupole fiducialization techniques used in the past and discusses why the vibrating wire technique is our method

  5. A semiconductor bridge ignited hot gas piston ejector

    NASA Technical Reports Server (NTRS)

    Grubelich, M. C.; Bickes, Robert W., Jr.

    1993-01-01

    The topics are presented in viewgraph form and include the following: semiconductor bridge technology (SCB); SCB philosophy; technology transfer; simplified sketch of SCB; SCB processing; SCB design; SCB test assembly; 5 mJ SCB burst based on a polaroid photograph; micro-convective heat transfer hypothesis; SCB fire set; comparison of SCB and hot-wire actuators; satellite firing sets; logic fire set; SCB smart component; SCB smart firing set; semiconductor design considerations; and the adjustable actuator system.

  6. Comparison of Jc characteristics in PIT wires based on BaFe2As2 with different substitutions

    NASA Astrophysics Data System (ADS)

    Tamegai, T.; Pyon, S.; Ding, Q. P.; Inoue, H.; Kobayashi, H.; Tsuchiya, Y.; Sun, Y.; Kajitani, H.; Koizumi, N.

    2014-05-01

    Three kinds of superconducting wires based on BaFe2As2 with different substitutions are fabricated using powder-in-tube method and characterized including magneto-optical imaging. In the case of (Ba,K)Fe2As2 wires processed by hot isostatic press, critical current density (Jc) of 32 kA/cm2 has been achieved at 4.2 K under self-field. Wires fabricated in a similar way with Ba(Fe,Co)2As2 resulted in much lower Jc of 7.8 kA/cm2 at 4.2 K under self-field. In the case of BaFe2(As,P)2, Jc of ambient-pressure processed wire has Jc of only 1.0 kA/cm2 at 4.2 K under self-field. Origins of these differences are discussed.

  7. Tensile deformation of NiTi wires.

    PubMed

    Gall, Ken; Tyber, Jeff; Brice, Valerie; Frick, Carl P; Maier, Hans J; Morgan, Neil

    2005-12-15

    We examine the structure and properties of cold drawn Ti-50.1 at % Ni and Ti-50.9 at % Ni shape memory alloy wires. Wires with both compositions possess a strong <111> fiber texture in the wire drawing direction, a grain size on the order of micrometers, and a high dislocation density. The more Ni rich wires contain fine second phase precipitates, while the wires with lower Ni content are relatively free of precipitates. The wire stress-strain response depends strongly on composition through operant deformation mechanisms, and cannot be explained based solely on measured differences in the transformation temperatures. We provide fundamental connections between the material structure, deformation mechanisms, and resulting stress-strain responses. The results help clarify some inconsistencies and common misconceptions in the literature. Ramifications on materials selection and design for emerging biomedical applications of NiTi shape memory alloys are discussed.

  8. Wire codes, magnetic fields, and childhood cancer

    SciTech Connect

    Kheifets, L.I.; Kavet, R.; Sussman, S.S.

    1997-05-01

    Childhood cancer has been modestly associated with wire codes, an exposure surrogate for power frequency magnetic fields, but less consistently with measured fields. The authors analyzed data on the population distribution of wire codes and their relationship with several measured magnetic field metrics. In a given geographic area, there is a marked trend for decreased prevalence from low to high wire code categories, but there are differences between areas. For average measured fields, there is a positive relationship between the mean of the distributions and wire codes but a large overlap among the categories. Better discrimination is obtained for the extremes of the measurement values when comparing the highest and the lowest wire code categories. Instability of measurements, intermittent fields, or other exposure conditions do not appear to provide a viable explanation for the differences between wire codes and magnetic fields with respect to the strength and consistency of their respective association with childhood cancer.

  9. Laser anemometer using a Fabry-Perot interferometer for measuring mean velocity and turbulence intensity along the optical axis in turbomachinery

    NASA Technical Reports Server (NTRS)

    Seasholtz, R. G.; Goldman, L. J.

    1982-01-01

    A technique for measuring a small optical axis velocity component in a flow with a large transverse velocity component is presented. Experimental results are given for a subsonic free jet operating in a laboratory environment, and for a 0.508 meter diameter turbine stator cascade. Satisfactory operation of the instrument was demonstrated in the stator cascade facility with an ambient acoustic noise level during operation of about 105 dB. In addition, the turbulence intensity measured with the interferometer was consistent with previous measurements taken with a fringe type laser anemometer.

  10. Wire frame to MOVIE. BYU transfer program

    SciTech Connect

    Robbins, D.; Byers, L.D.; Benner, M.S.

    1982-12-01

    At SNLA, the primary computer-aided drafting tool is the Applicon Graphics System (AGS). The data base for mechanical parts on the AGS is a wire frame model. This report summarizes a method of adding surface information to the wire frame and passing this information up stream to MOVIE.BYU which is on a VAX computer and is used to produce shaded graphics pictures of the AGS wire frame model on a RAMTEK 9400 display terminal.

  11. Wrapped Wire Detects Rupture Of Pressure Vessel

    NASA Technical Reports Server (NTRS)

    Hunt, James B.

    1990-01-01

    Simple, inexpensive technique helps protect against damage caused by continuing operation of equipment after rupture or burnout of pressure vessel. Wire wrapped over area on outside of vessel where breakthrough most likely. If wall breaks or burns, so does wire. Current passing through wire ceases, triggering cutoff mechanism stopping flow in vessel to prevent further damage. Applied in other situations in which pipes or vessels fail due to overpressure, overheating, or corrosion.

  12. Space Shuttle Columbia Aging Wiring Failure Analysis

    NASA Technical Reports Server (NTRS)

    McDaniels, Steven J.

    2005-01-01

    A Space Shuttle Columbia main engine controller 14 AWG wire short circuited during the launch of STS-93. Post-flight examination divulged that the wire had electrically arced against the head of a nearby bolt. More extensive inspection revealed additional damage to the subject wire, and to other wires as well from the mid-body of Columbia. The shorted wire was to have been constructed from nickel-plated copper conductors surrounded by the polyimide insulation Kapton, top-coated with an aromatic polyimide resin. The wires were analyzed via scanning electron microscope (SEM), energy dispersive X-Ray spectroscopy (EDX), and electron spectroscopy for chemical analysis (ESCA); differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) were performed on the polyimide. Exemplar testing under laboratory conditions was performed to replicate the mechanical damage characteristics evident on the failed wires. The exemplar testing included a step test, where, as the name implies, a person stepped on a simulated wire bundle that rested upon a bolt head. Likewise, a shear test that forced a bolt head and a torque tip against a wire was performed to attempt to damage the insulation and conductor. Additionally, a vibration test was performed to determine if a wire bundle would abrade when vibrated against the head of a bolt. Also, an abrasion test was undertaken to determine if the polyimide of the wire could be damaged by rubbing against convolex helical tubing. Finally, an impact test was performed to ascertain if the use of the tubing would protect the wire from the strike of a foreign object.

  13. Thin-wire scatterers in chiral media.

    PubMed

    Jaggard, D L; Liu, J C; Grot, A; Pelet, P

    1991-06-01

    The effect of the handedness of chiral materials on the differential scattering cross section of embedded conducting wires is examined. The bow-tie-shaped induced current distributions and the resulting forbidden zone of radiation are explained through fundamental physical principles. We find that thin-wire scatterers can be divided into subchiral, chiral, and superchiral classes according to the degree of chirality of the host material and the electromagnetic length of the wire.

  14. Nondestructive Evaluation of Aircraft and Spacecraft Wiring

    NASA Technical Reports Server (NTRS)

    White, John E.; Tucholski, Edward J.; Green, Robert E., Jr.

    2004-01-01

    Spacecraft, and especially aircraft, often fry well past their original design lives and, therefore, the need to develop nondestructive evaluation procedures for inspection of vital structures in these craft is extremely important. One of the more recent problems is the degradation of wiring and wiring insulation. The present paper describes several nondestructive characterization methods which afford the possibility to detect wiring and insulation degradation in-situ prior to major problems with the safety of aircraft and spacecraft.

  15. Development of the Axial Instability in Low Wire Number Wire Array Z-Pinches

    SciTech Connect

    Knapp, P. F.; Bell, K. S.; Blesener, I. C.; Chalenski, D. A.; Douglass, J. D.; Greenly, J. B.; Martin, M. R.; McBride, R. D.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Kusse, B. R.; Hall, G. N.

    2009-01-21

    We are investigating the development of the axial instability, a modulation of the size of the coronal plasma that develops around each wire in wire-array Z-pinches. The modulation is a result of nonuniform ablation of material from the relatively cold wire core. It has long been known that the wavelength of this modulation is constant late in time and, since it is unique to different materials, it has come to be known as the fundamental mode. In these experiments we imaged individual wires with laser shadowgraphy early in time primarily in low wire number, large wire diameter aluminum arrays for ease of viewing. We Observe the development of this modulation from the time of initiation of coronal plasma, obtaining its dominant wavelength and amplitude growth as a function of time. We also studied the instability on coiled wires, which modify the wire ablation mechanism and completely suppress the fundamental mode[Hall2008]. time is discussed.

  16. 49 CFR 234.241 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... underground wire. 234.241 Section 234.241 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING... Testing Maintenance Standards § 234.241 Protection of insulated wire; splice in underground...

  17. 49 CFR 234.241 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... underground wire. 234.241 Section 234.241 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING... Testing Maintenance Standards § 234.241 Protection of insulated wire; splice in underground...

  18. 49 CFR 234.241 - Protection of insulated wire; splice in underground wire.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... underground wire. 234.241 Section 234.241 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING... Testing Maintenance Standards § 234.241 Protection of insulated wire; splice in underground...

  19. Wired.

    ERIC Educational Resources Information Center

    Conklin, Aaron R.

    1998-01-01

    Discusses technology's impact on scoreboard design: the development of the light-emitting diode (LED) display. How the LED system works is explained, as are the advantages and disadvantages of LED compared with incandescent lamp boards. Final comments address deciding on materials for scoreboard casings. (GR)

  20. Wired

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    Every American grade school and library ought to have free access to the Internet, and universities and institutions ought to have better access, according to the Clinton Administration.In an October 10 speech in Knoxville, Tennessee, President Clinton proposed that all of the nation's 100,000 public schools and 9,000 libraries receive a two-tiered E-rate (education rate) for access to Internet services. All schools and libraries should receive basic connections for free, as well as deep discounts on video conferencing and highspeed connections (with prices influenced by how much the school can afford to pay). The basic connections (and part of the cost of the more sophisticated connections) would be paid from a special federal fund that currently provides below-cost phone service to households in poor and rural areas. That fund is currently drawn from fees assessed on local and long-distance telephone providers; the Clinton Administration would have cable operators and cellular service providers contribute as well. Companies that provide Internet services would be paid at the best available commercial rate.

  1. A deployable .015 inch diameter wire antenna

    NASA Technical Reports Server (NTRS)

    Dibiasi, L.

    1979-01-01

    This mechanism was developed to dispense a small diameter wire which serves as a receiving antenna for electric field measurements on an Earth orbiting satellite. The antenna is deployed radially from a spinning satellite. A brushless dc motor drives a storage spool to dispense the wire at a controlled rate. Centrifugal force, acting on a mass attached to the end of the wire, keeps the wire in the radial position. The mechanism design, testing, and performance characteristics are discussed. Finally, operational data of the mechanism while in orbit are presented.

  2. Ferromagnetic resonance in submicron amorphous wires

    NASA Astrophysics Data System (ADS)

    Kraus, Luděk; Frait, Zdeněk; Ababei, Gabriel; Chayka, Oleksandr; Chiriac, Horia

    2012-03-01

    Ferromagnetic resonance in glass-coated amorphous wires with the diameter of metallic core varying from 25 μm to 133 nm is investigated. The microwave frequencies of 49.1 and 69.7 GHz are used and static magnetic field is applied either parallel or perpendicular to the long wire axis. In agreement with theoretical predictions the resonance curves of submicron wires substantially differ from the curves of the bulk wires. Depending on the symmetry and intensity of microwave electric and magnetic fields in the sample vicinity the circumferential and/or dipolar resonance modes can be excited. In bulk wires the resonance fields of the two modes coincide. In submicron wires, however, their resonance fields differ, indicating the metallic character of the circumferential mode and the insulator character of the dipolar mode. In wires with diameters 717 and 869 nm radial standing spin wave resonances are observed in parallel field configuration. The experimental results for the parallel field configuration can be well explained by the rigorous theoretical model. From the fit of experimental data the exchange stiffness constant A = 8.2 10-12 J/m and perpendicular surface anisotropy constant Ks = 6 × 10-4 J/m2 are obtained. The resonance curves measured in the transversal field configuration can be well explained in the frame of the skin effect and quasistatic approximations for the bulk and submicron wires, respectively. In submicron wires, however, an additional resonance of unknown origin is observed at higher magnetic fields.

  3. Development of parallel wire regenerator for cryocoolers

    NASA Astrophysics Data System (ADS)

    Nam, Kwanwoo; Jeong, Sangkwon

    2006-04-01

    This paper describes development of a novel regenerator geometry for cryocoolers. Parallel wire type is a wire bundle stacked in parallel with the flow in the housing, which is similar to a conventional parallel plate or tube. Simple and unique fabrication procedure is developed and fully depicted in this paper. Hydrodynamic and thermal experiments are performed to demonstrate the feasibility of the parallel wire regenerator. First, pressure drop characteristic of the parallel wire regenerator is compared to that of the screen mesh regenerator. Experimental result shows that the steady flow friction factor of the parallel wire type is three to five times smaller than that of the screen mesh type. Second, thermal ineffectiveness is determined by measuring the instantaneous pressure, the flow rate and the gas temperature at the warm and cold ends of the regenerator. The measured ineffectiveness of the parallel wire regenerator is larger than that of the screen regenerator due to the excessive axial conduction loss. To alleviate the intrinsic axial conduction loss of the parallel wire regenerator, segmentation is introduced and the experimental results reveal the favorable effect of the segmentation. Entropy generation calculation is adopted to compare the total losses between the screen regenerator and the parallel wire regenerator for various operating ranges. Simulation results show that the parallel wire regenerator can be an attractive candidate to improve cryocooler performance especially for the case of smaller NTU and lower cold-end temperature.

  4. Discharge electrode wire assembly for electrostatic precipitator

    SciTech Connect

    Ivester, F. D.; Troulias, J. R.

    1985-03-05

    An electrostatic precipitator having a casing defining a precipitation chamber wherein a plurality of discharge electrode frames are disposed alternately between a plurality of collecting electrode plates. Each discharge electrode frame is comprised of a plurality of individual discharge electrode wires tautly strung across a support frame. Individual discharge electrode wires are maintained in a taut condition during operation by tensioning coil springs which interconnect neighboring discharge electrode wires to take-up any lengthening of the discharge electrode wires in a horizontal direction.

  5. Superconducting-wire fabrication. Final report

    SciTech Connect

    Glad, W.E.; Chase, G.G.

    1990-05-01

    Experiments were done leading to the fabrication of high-temperature superconducting composite wire. Bulk superconductor was characterized by using optical microscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. The chemical compatibility of superconducting materials with a number of metal sheathing candidates was tested, with silver offering the best compatibility. Wire was fabricated by drawing 0.250-inch-diameter silver tubing packed with superconducting powder. Single core wires were drawn to 0.037-inch diameter. The best critical current performance (660 A/cm2) for leaded bismuth 2-2-2-3 material was achieved by flattening single-core wire before heat treatment.

  6. Effect of an Axial Wire on Conical Wire Array Z-Pinch Radiation

    SciTech Connect

    Presura, R.; Martinez, D.; Wright, S.; Plechaty, C.; Neff, S.; Wanex, L.; Ampleford, D. J.

    2009-01-21

    Adding a wire on the axis of wire arrays significantly affects the x-ray emission of the conical arrays, and much less that of the cylindrical ones. The radiation of the conical wire arrays increases with the thickness of the central wire, surpassing that of the equivalent cylindrical arrays. Significant energy is emitted early on, around the time of the conical shock formation, before the pinch stagnation.

  7. Processing a printed wiring board by single bath electrodeposition

    DOEpatents

    Meltzer, Michael P.; Steffani, Christopher P.; Gonfiotti, Ray A.

    2010-12-07

    A method of processing a printed wiring board. Initial processing steps are implemented on the printed wiring board. Copper is plated on the printed wiring board from a bath containing nickel and copper. Nickel is plated on the printed wiring board from a bath containing nickel and copper and final processing steps are implemented on the printed wiring board.

  8. Processing A Printed Wiring Board By Single Bath Electrodeposition

    DOEpatents

    Meltzer, Michael P.; Steffani, Christopher P.; Gonfiotti, Ray A.

    2003-04-15

    A method of processing a printed wiring board by single bath electrodeposition. Initial processing steps are implemented on the printed wiring board. Copper is plated on the printed wiring board from a bath containing nickel and copper. Nickel is plated on the printed wiring board from the bath containing nickel and copper and final processing steps are implemented on the printed wiring board.

  9. 47 CFR 76.804 - Disposition of home run wiring.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Disposition of home run wiring. 76.804 Section... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cable Inside Wiring § 76.804 Disposition of home run wiring. (a) Building-by-building disposition of home run wiring. (1) Where an MVPD owns the home run wiring in an...

  10. 47 CFR 76.804 - Disposition of home run wiring.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Disposition of home run wiring. 76.804 Section... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cable Inside Wiring § 76.804 Disposition of home run wiring. (a) Building-by-building disposition of home run wiring. (1) Where an MVPD owns the home run wiring in an...

  11. 47 CFR 76.804 - Disposition of home run wiring.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Disposition of home run wiring. 76.804 Section... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cable Inside Wiring § 76.804 Disposition of home run wiring. (a) Building-by-building disposition of home run wiring. (1) Where an MVPD owns the home run wiring in an...

  12. 29 CFR 1926.1413 - Wire rope-inspection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... Apparent deficiencies in this category are: (A) Visible broken wires, as follows: (1) In running wire ropes: Six randomly distributed broken wires in one rope lay or three broken wires in one strand in one rope... around the rope. (2) In rotation resistant ropes: Two randomly distributed broken wires in six...

  13. 29 CFR 1926.1413 - Wire rope-inspection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... Apparent deficiencies in this category are: (A) Visible broken wires, as follows: (1) In running wire ropes: Six randomly distributed broken wires in one rope lay or three broken wires in one strand in one rope... around the rope. (2) In rotation resistant ropes: Two randomly distributed broken wires in six...

  14. Kirschner wire pin tract infection rates: a randomized controlled trial between percutaneous and buried wires.

    PubMed

    Hargreaves, D G; Drew, S J; Eckersley, R

    2004-08-01

    This prospective, randomized trial compares the infection rates of Kirschner wires left percutaneously and those buried deep to the skin in a group of patients with isolated distal radial fractures. Percutaneous wires had a significantly greater infection rate than wires which were buried deep to the skin.

  15. Arkansas' Anemometer Loan Program

    SciTech Connect

    Fernando Vego

    2012-10-11

    The measurement campaign had one year duration from 04/01/2011 to 03/31/2012 and was taken at 20m and 34m with NRG instrumentation. The data was analyzed weekly to check inconsistencies and validity and processed using Excel, Flexpro and Windographer standard Edition Version 2.04. The site analyzed is located in the Waldron, Arkansas in Scott County. It is an open site for most of the direction sectors with immediate roughness class of 1.5. It has seasonally directional winds, of which the most energetic come from the southern direction. The vertical wind profile shows moderate wind shear that varies by season as well.

  16. Nanosecond electrical explosion of thin aluminum wires in a vacuum: Experimental and computational investigations

    SciTech Connect

    Sarkisov, G.S.; Rosenthal, S.E.; Cochrane, K.R.; Struve, K.W.; Deeney, C.; McDaniel, D.H.

    2005-04-01

    Experimental and computational investigations of nanosecond electrical explosion of a thin Al wire in vacuum are presented. We have demonstrated that increasing the current rate leads to increased energy deposited before voltage collapse. The experimental evidence for synchronization of the wire expansion and light emission with voltage collapse is presented. Hydrocarbons are indicated in optical spectra and their influence on breakdown physics is discussed. The radial velocity of low-density plasma reaches a value of {approx}100 km/s. The possibility of an overcritical phase transition due to high pressure is discussed. A one-dimensional magnetohydrodynamic (MHD) simulation shows good agreement with experimental data. The MHD simulation demonstrates separation of the exploding wire into a high-density cold core and a low-density hot corona as well as fast rejection of the current from the wire core to the corona during voltage collapse. Important features of the dynamics for the wire core and corona follow from the MHD simulation and are discussed.

  17. Nanosecond electrical explosion of thin aluminum wire in vacuum : experimental and computational investigations.

    SciTech Connect

    Cochrane, Kyle Robert; Struve, Kenneth William; Rosenthal, Stephen Edgar; McDaniel, Dillon Heirman; Sarkisov, Gennady Sergeevich; Deeney, Christopher

    2004-06-01

    The experimental and computational investigations of nanosecond electrical explosion of thin Al wire in vacuum are presented. We have demonstrated that increasing the current rate leads to increased energy deposited before voltage collapse. Laser shadowgrams of the overheated Al core exhibit axial stratification with a {approx}100 {micro}m period. The experimental evidence for synchronization of the wire expansion and light emission with voltage collapse is presented. Two-wavelength interferometry shows an expanding Al core in a low-ionized gas condition with increasing ionization toward the periphery. Hydrocarbons are indicated in optical spectra and their influence on breakdown physics is discussed. The radial velocity of low-density plasma reaches a value of {approx}100 km/s. The possibility of an overcritical phase transition due to high pressure is discussed. 1D MHD simulation shows good agreement with experimental data. MHD simulation demonstrates separation of the exploding wire into a high-density cold core and a low-density hot corona as well as fast rejection of the current from the wire core to the corona during voltage collapse. Important features of the dynamics for wire core and corona follow from the MHD simulation and are discussed.

  18. Tuning a Tetrahertz Wire Laser

    NASA Technical Reports Server (NTRS)

    Qin, Qi; Williams, Benjamin S.; Kumar, Sushil; Reno, John L.; Hu, Qing

    2009-01-01

    Tunable terahertz lasers are desirable in applications in sensing and spectroscopy because many biochemical species have strong spectral fingerprints at terahertz frequencies. Conventionally, the frequency of a laser is tuned in a similar manner to a stringed musical instrument, in which pitch is varied by changing the length of the string (the longitudinal component of the wave vector) and/ or its tension (the refractive index). However, such methods are difficult to implement in terahertz semiconductor lasers because of their poor outcoupling efficiencies. Here, we demonstrate a novel tuning mechanism based on a unique 'wire laser' device for which the transverse dimension w is much much less than lambda. Placing a movable object close to the wire laser manipulates a large fraction of the waveguided mode propagating outside the cavity, thereby tuning its resonant frequency. Continuous single-mode redshift and blueshift tuning is demonstrated for the same device by using either a dielectric or metallic movable object. In combination, this enables a frequency tuning of approximately equal to 137 GHz (3.6%) from a single laser device at approximately equal to 3.8 THz.

  19. Comparison of critical current density in SiC-doped in situ MgB2 coils and straight wire samples processed by HIP

    NASA Astrophysics Data System (ADS)

    Gajda, D.; Morawski, A.; Zaleski, A.; Cetner, T.; Małecka, M.; Presz, A.; Rindfleisch, M.; Tomsic, M.; Thong, C. J.; Surdacki, P.

    2013-11-01

    Unreacted MgB2 wires fabricated from SiC-doped precursor material by Hyper Tech Research, Inc. have been used to make small-diameter (14 mm) superconducting coils. All coils made of 500 mm length wires were subjected to hot isostatic pressure (HIP) treatment. The critical current density (Jc) parameters of coils were compared to straight samples characteristics. Both types of samples have been measured in perpendicular magnetic field configuration for Jc and pinning force density (Fp) evaluation. No significant Jc difference between the long wires on coils and straight wires was found. These results suggest that the critical current (Ic) for coils can be determined for straight samples (25 mm). SEM analysis indicated that a small diameter of the coil does not influence the structure of in situ MgB2 wire.

  20. Improved Superconducting Wire for Wind Generators: Superconducting Wires for Direct-Drive Wind Generators

    SciTech Connect

    2012-01-01

    REACT Project: Brookhaven National Laboratory will develop a low-cost superconducting wire that could be used in high-power wind generators. Superconducting wire currently transports 600 times more electric current than a similarly sized copper wire, but is significantly more expensive. Brookhaven National Laboratory will develop a high-performance superconducting wire that can handle significantly more electrical current, and will demonstrate an advanced manufacturing process that has the potential to yield a several-fold reduction in wire costs while using a using negligible amount of rare earth material. This design has the potential to make a wind turbine generator lighter, more powerful, and more efficient, particularly for offshore applications.

  1. Twisted Pair Of Insulated Wires Senses Moisture

    NASA Technical Reports Server (NTRS)

    Laue, Eric G.; Stephens, James B.

    1989-01-01

    Sensitivity of electronic moisture sensor to low levels of moisture increased by new electrode configuration. Moisture-sensing circuit described in "Low-Cost Humidity Sensor" (NPO-16544). New twisted pair of wires takes place of flat-plate capacitor in circuit. Configuration allows for thermal expansion and contraction of polymer while maintaining nearly constant area of contact between polymer and wires.

  2. Microfabricated wire arrays for Z-pinch.

    SciTech Connect

    Spahn, Olga Blum; Rowen, Adam M.; Cich, Michael Joseph; Peake, Gregory Merwin; Arrington, Christian L.; Nash, Thomas J.; Klem, John Frederick; Romero, Dustin Heinz

    2008-10-01

    Microfabrication methods have been applied to the fabrication of wire arrays suitable for use in Z. Self-curling GaAs/AlGaAs supports were fabricated as an initial route to make small wire arrays (4mm diameter). A strain relief structure that could be integrated with the wire was designed to allow displacements of the anode/cathode connections in Z. Electroplated gold wire arrays with integrated anode/cathode bus connections were found to be sufficiently robust to allow direct handling. Platinum and copper plating processes were also investigated. A process to fabricate wire arrays on any substrate with wire thickness up to 35 microns was developed. Methods to handle and mount these arrays were developed. Fabrication of wire arrays of 20mm diameter was demonstrated, and the path to 40mm array fabrication is clear. With some final investment to show array mounting into Z hardware, the entire process to produce a microfabricated wire array will have been demonstrated.

  3. 30 CFR 56.12047 - Guy wires.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Guy wires. 56.12047 Section 56.12047 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity § 56.12047 Guy wires....

  4. 30 CFR 56.12047 - Guy wires.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Guy wires. 56.12047 Section 56.12047 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity § 56.12047 Guy wires....

  5. 30 CFR 56.12047 - Guy wires.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Guy wires. 56.12047 Section 56.12047 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity § 56.12047 Guy wires....

  6. 30 CFR 56.12047 - Guy wires.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Guy wires. 56.12047 Section 56.12047 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity § 56.12047 Guy wires....

  7. 30 CFR 56.12047 - Guy wires.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Guy wires. 56.12047 Section 56.12047 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity § 56.12047 Guy wires....

  8. 29 CFR 1919.79 - Wire rope.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Wire rope. 1919.79 Section 1919.79 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) GEAR CERTIFICATION Certification of Shore-Based Material Handling Devices § 1919.79 Wire rope. (a)...

  9. Welding torch and wire feed manipulator

    NASA Technical Reports Server (NTRS)

    Williams, R. T.

    1967-01-01

    Welding torch and wire feed manipulator increase capability for performing automatic welding operations. The manipulator rotates on its horizontal axis to avoid obstacles as they approach the torch. The initial individual attitudes of the torch and wire guide are set with respect to the general configuration of the part.

  10. Ultra-flexible biomedical electrodes and wires

    NASA Technical Reports Server (NTRS)

    Rositano, S. A.

    1970-01-01

    Soft, flexible electrode conforms to body contour during body motion. It is fabricated from an elastomer impregnated with a conductive powder which can be configured into any required shape, including a wire shape to connect the electrode directly to an electrical instrument or to a conventional metallic wire.

  11. Superconducting wire with improved strain characteristics

    DOEpatents

    Luhman, Thomas; Klamut, Carl J.; Suenaga, Masaki; Welch, David

    1982-01-01

    A superconducting wire comprising a superconducting filament and a beryllium strengthened bronze matrix in which the addition of beryllium to the matrix permits a low volume matrix to exhibit reduced elastic deformation after heat treating which increases the compression of the superconducting filament on cooling and thereby improves the strain characteristics of the wire.

  12. Superconducting wire with improved strain characteristics

    DOEpatents

    Luhman, Thomas; Klamut, Carl J.; Suenaga, Masaki; Welch, David

    1982-01-01

    A superconducting wire comprising a superconducting filament and a beryllium strengthened bronze matrix in which the addition of beryllium to the matrix permits a low volume matrix to exhibit reduced elastic deformation after heat treating which increases the compression of the superconducting filament on cooling and thereby improve the strain characteristics of the wire.

  13. Superconducting wire with improved strain characteristics

    DOEpatents

    Luhman, T.; Klamut, C.J.; Suenaga, M.; Welch, D.

    1979-12-19

    A superconducting wire comprising a superconducting filament and a beryllium strengthened bronze matrix in which the addition of beryllium to the matrix permits a low volume matrix to exhibit reduced elastic deformation after heat treating which increases the compression of the superconducting filament on cooling and thereby improve the strain characteristics of the wire.

  14. Flywheel system using wire-wound rotor

    DOEpatents

    Chiao, Edward Young; Bender, Donald Arthur; Means, Andrew E.; Snyder, Philip K.

    2016-06-07

    A flywheel is described having a rotor constructed of wire wound onto a central form. The wire is prestressed, thus mitigating stresses that occur during operation. In another aspect, the flywheel incorporates a low-loss motor using electrically non-conducting permanent magnets.

  15. LANSCE-R WIRE-SCANNER SYSTEM

    SciTech Connect

    Gruchalla, Michael E.

    2011-01-01

    The National Instruments cRIO platform is used for the new LANSCE-R wire-scanner systems. All wire-scanner electronics are integrated into a single BiRa BiRIO 4U cRIO chassis specifically designed for the cRIO crate and all interface electronics. The BiRIO chassis, actuator and LabVIEW VIs provide a complete wire-scanner system integrated with EPICS. The new wire-scanner chassis includes an 8-slot cRIO crate with Virtex-5 LX 110 FPGA and Power-PC real-time controller, the LANL-developed cRIO 2-axis wire-sensor analog interface module (AFE), NI9222 cRIO 4-channel 16-bit digitizer, cRIO resolver demodulator, cRIO event receiver, front-panel touch panel display, motor driver, and all necessary software, interface wiring, connectors and ancillary components. This wirescanner system provides a complete, turn-key, 2-axis wire-scanner system including 2-channel low-noise sensewire interface with variable DC wire bias and wireintegrity monitor, 16-bit signal digitizers, actuator motor drive and control, actuator position sensing, limit-switch interfaces, event receiver, LabVIEW and EPICS interface, and both remote operation and full stand-alone operation using the touch panel.

  16. 47 CFR 32.2431 - Aerial wire.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Aerial wire. 32.2431 Section 32.2431 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2431 Aerial wire....

  17. 47 CFR 32.2431 - Aerial wire.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Aerial wire. 32.2431 Section 32.2431 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2431 Aerial wire....

  18. SpaceWire Architectures: Present and Future

    NASA Technical Reports Server (NTRS)

    Rakow, Glen Parker

    2006-01-01

    A viewgraph presentation on current and future spacewire architectures is shown. The topics include: 1) Current Spacewire Architectures: Swift Data Flow; 2) Current SpaceWire Architectures : LRO Data Flow; 3) Current Spacewire Architectures: JWST Data Flow; 4) Current SpaceWire Architectures; 5) Traditional Systems; 6) Future Systems; 7) Advantages; and 8) System Engineer Toolkit.

  19. Lansce Wire Scanning Diagnostics Device Mechanical Design

    SciTech Connect

    Rodriguez Esparza, Sergio; Batygin, Yuri K.; Gilpatrick, John D.; Gruchalla, Michael E.; Maestas, Alfred J.; Pillai, Chandra; Raybun, Joseph L.; Sattler, F. D.; Sedillo, James Daniel; Smith, Brian G.

    2011-01-01

    The Accelerator Operations & Technology Division at Los Alamos National Laboratory operates a linear particle accelerator which utilizes 110 wire scanning diagnostics devices to gain position and intensity information of the proton beam. In the upcoming LANSCE improvements, 51 of these wire scanners are to be replaced with a new design, up-to-date technology and off-the-shelf components. This document outlines the requirements for the mechanical design of the LANSCE wire scanner and presents the recently developed linac wire scanner prototype. Additionally, this document presents the design modifications that have been implemented into the fabrication and assembly of this first linac wire scanner prototype. Also, this document will present the design for the second, third, and fourth wire scanner prototypes being developed. Prototypes 2 and 3 belong to a different section of the particle accelerator and therefore have slightly different design specifications. Prototype 4 is a modification of a previously used wire scanner in our facility. Lastly, the paper concludes with a plan for future work on the wire scanner development.

  20. Wire ageing with the TEA photocathode

    SciTech Connect

    Va`vra, J.

    1996-06-01

    Recently several RICH protypes successfully tested a gaseous TEA photocathode. However, its wire ageing behavior is unknown. In principle, TEA is a more strongly bonded molecule than TMAE, and, as a result, one would expect better wire ageing behavior. This paper explores this question.

  1. Assessment of Proton Deflectometry for Exploding Wire Experiments

    NASA Astrophysics Data System (ADS)

    Bott, S.; Wei, M.; Mariscal, D.; Gunasekera, K.; Collins, G.; Beg, F.; Kindel, J.; Covington, A.; Presura, R.; Legalloudec, N.; Wiewior, P.; Plechaty, C.; Burris-Mog, T.; Paudel, Y.; Stein, S.; Chalyy, O.; Astanovitskiy, A.

    2010-11-01

    Determination of B-field structures in pulsed power driven exploding wire experiments is vital to the benchmarking of 3D simulations, but is complicated by the presence of large volumes of hot, dense plasma. Optical and electrical probe diagnostics typically fail early in the experiment. We present progress on a new project which examines the use of proton deflectometry to measure magnetic fields in pulsed power plasmas. Experimental work is carried out at the Nevada Test Facility (NTF) using both 10J 0.3ps Leopard laser and the 1.6MA ZEBRA pulsed power driver. Leopard provided focussed intensities of ˜5x10^19 W cm-2, and generated up to 8 MeV protons from thin metallic targets with good reproducibility and low divergence. The first tests of proton beam deflection in pulsed power experiments, along with comparison to initial simulation work will be presented.

  2. 47 CFR 76.804 - Disposition of home run wiring.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... wiring. The incumbent provider that has elected to abandon its home run wiring may remove its amplifiers... amplifiers or other active devices used in the wiring if an equivalent replacement can easily be...

  3. 47 CFR 76.804 - Disposition of home run wiring.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... wiring. The incumbent provider that has elected to abandon its home run wiring may remove its amplifiers... amplifiers or other active devices used in the wiring if an equivalent replacement can easily be...

  4. Wiring harnesses documented by punched-card technique

    NASA Technical Reports Server (NTRS)

    Hicks, W. W.; Kloezeman, W. G.

    1970-01-01

    Cards representing a connector are punched, sorted, and then used to printout wiring documentation for that connector. When wiring changes are made, new cards are punched and the wiring documentation is reprinted to reflect the latest configuration.

  5. Long-Wearing Wire Guide For Welding Torch

    NASA Technical Reports Server (NTRS)

    Gutow, David A.; Burley, Richard K.; Gilbert, Jeffrey L.; Fogel, Irving

    1992-01-01

    Insert for wire-guide tube on tungsten/inert-gas welding apparatus extends life of guide tube and increases accuracy of weld. Hardened insert resists wear by sliding tungsten wire. Chamfer guides wire into insert.

  6. Stiffness Corrections for the Vibration Frequency of a Stretched Wire

    ERIC Educational Resources Information Center

    Hornung, H. G.; Durie, M. J.

    1977-01-01

    Discusses the need of introducing corrections due to wire stiffness arising from end constraints and wire axis distribution curvature in the measurement of ac electrical frequency by exciting transverse standing waves in a stretched steel wire. (SL)

  7. Method of preparing composite superconducting wire

    DOEpatents

    Verhoeven, John D.; Gibson, Edwin D.; Finnemore, Douglas K.; Ostenson, Jerome E.; Schmidt, Frederick A.; Owen, Charles V.

    1985-08-06

    An improved method of preparing composite multifilament superconducting wire of Nb.sub.3 Sn in a copper matrix which eliminates the necessity of coating the drawn wire with tin. A generalized cylindrical billet of an alloy of copper containing at least 15 weight percent niobium, present in the copper as discrete, randomly distributed and oriented dendritic-shaped particles, is provided with at least one longitudinal opening which is filled with tin to form a composite drawing rod. The drawing rod is then drawn to form a ductile composite multifilament wire containing a filament of tin. The ductile wire containing the tin can then be wound into magnet coils or other devices before heating to diffuse the tin through the wire to react with the niobium forming Nb.sub.3 Sn. Also described is an improved method for making large billets of the copper-niobium alloy by consumable-arc casting.

  8. Improved method of preparing composite superconducting wire

    DOEpatents

    Verhoeven, J.D.; Gibson, E.D.; Finnemore, D.K.; Ostenson, J.E.; Schmidt, F.A.; Owen, C.V.

    1979-10-17

    An improved method of preparing composite multifilament superconducting wire of Nb/sub 3/Sn in a copper matrix eliminates the necessity of coating the drawn wire with tin. A generalized cylindrical billet of an alloy of copper containing at least 15 weight percent niobium, present in the copper as discrete, randomly distributed and oriented dendritic-shaped particles, is provided with at least one longitudinal opening which is filled with tin to form a composite drawing rod. The drawing rod is then drawn to form a ductile composite multifilament wire containing a filament of tin. The ductile wire containing the tin can then be wound into magnet coils or other devices before heating to diffuse the tin through the wire to react with the niobium forming Nb/sub 3/Sn. Also described is an improved method for making large billets of the copper-niobium alloy by consumable-arc casting.

  9. Wire and Cable Cold Bending Test

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony

    2010-01-01

    One of the factors in assessing the applicability of wire or cable on the lunar surface is its flexibility under extreme cold conditions. Existing wire specifications did not address their mechanical behavior under cold, cryogenic temperature conditions. Therefore tests were performed to provide this information. To assess this characteristic 35 different insulated wire and cable pieces were cold soaked in liquid nitrogen. The segments were then subjected to bending and the force was recorded. Any failure of the insulation or jacketing was also documented for each sample tested. The bending force tests were performed at room temperature to provide a comparison to the change in force needed to bend the samples due to the low temperature conditions. The results from the bending tests were plotted and showed how various types of insulated wire and cable responded to bending under cold conditions. These results were then used to estimate the torque needed to unroll the wire under these low temperature conditions.

  10. Wiring Damage Analyses for STS OV-103

    NASA Technical Reports Server (NTRS)

    Thomas, Walter, III

    2006-01-01

    This study investigated the Shuttle Program s belief that Space Transportation System (STS) wiring damage occurrences are random, that is, a constant occurrence rate. Using Problem Reporting and Corrective Action (PRACA)-derived data for STS Space Shuttle OV-103, wiring damage was observed to increase over the vehicle s life. Causal factors could include wiring physical deterioration, maintenance and inspection induced damage, and inspection process changes resulting in more damage events being reported. Induced damage effects cannot be resolved with existent data. Growth analysis (using Crow-AMSAA, or CA) resolved maintenance/inspection effects (e.g., heightened awareness) on all wire damages and indicated an overall increase since Challenger Return-to-Flight (RTF). An increasing failure or occurrence rate per flight cycle was seen for each wire damage mode; these (individual) rates were not affected by inspection process effects, within statistical error.

  11. On Wires Holding a Handful of Electrons

    NASA Astrophysics Data System (ADS)

    Beiu, Valeriu; Ibrahim, Walid; Makki, Rafic Z.

    When analyzing reliability, wires have in most cases been ignored, with gates (and devices) taking the lion’s share. With scaling, this “only computing fails” approach is not going to be accurate enough as communication (wires) will also start to err. Trying to do justice to wires, this paper details a statistical failure analysis of wires following on the few papers which have made wires’ reliability their concern. We will use a classical particle-like probabilistic approach to enhance on the accuracy of wires’ length-dependent probabilities of failure due to the discreetness of charge. Covering some of the intrinsic noises, such an approach leads to “lower bound”-like wire reliability estimates, as ignoring other intrinsic noises, as well as extrinsic noises, variations, and defects. These results should have implications for multi-/many-cores and networks-on-chip, as well as forward-looking investigations on emerging nano-architectures.

  12. Realization of a Strained Atomic Wire Superlattice.

    PubMed

    Song, Inkyung; Goh, Jung Suk; Lee, Sung-Hoon; Jung, Sung Won; Shin, Jin Sung; Yamane, Hiroyuki; Kosugi, Nobuhiro; Yeom, Han Woong

    2015-11-24

    A superlattice of strained Au-Si atomic wires is successfully fabricated on a Si surface. Au atoms are known to incorporate into the stepped Si(111) surface to form a Au-Si atomic wire array with both one-dimensional (1D) metallic and antiferromagnetic atomic chains. At a reduced density of Au, we find a regular array of Au-Si wires in alternation with pristine Si nanoterraces. Pristine Si nanoterraces impose a strain on the neighboring Au-Si wires, which modifies both the band structure of metallic chains and the magnetic property of spin chains. This is an ultimate 1D version of a strained-layer superlattice of semiconductors, defining a direction toward the fine engineering of self-assembled atomic-scale wires. PMID:26446292

  13. The aging of wire chambers filled with dimethyl ether: wire and construction materials and freon impurities

    NASA Astrophysics Data System (ADS)

    Jibaly, Mohammed; Majewski, Stan; Chrusch, Peter; Wojcik, Randolph; Sauli, Fabio; Gaudaen, Jan

    1989-11-01

    This is a complete summary of our study of the aging of different types of wire chambers, with a variety of construction materials and wires, filled with dimethyl ether (DME) of varying degrees of purity. The resistive Nicotin and Stablohm wires were corroded by DME, producing fast aging. The moderately resistive stainless steel wires were able to withstand extended irradiation (up to 1 C/cm) in high-purity DME without any apparent damage; and gold-plated tungsten and molybdenum wires exhibited a comparable behavior. Many construction materials were tested and recommendations are thus reached as to what kinds of materials are safe in building DME-operated wire chambers. Among many different Freon and hydrocarbon impurities detected in DME by means of gas chromatography (GC), Freon-11 was found to be mostly responsible for the aging, even with noncorrosive stainless steel or gold-plated wires. The availability and feasibility of obtaining Freon-free DME is reported as well.

  14. Quench degradation limit of multifilamentary AgBi2Sr2CaCu2Ox round wires

    DOE PAGESBeta

    Ye, Liyang; Li, Pei; Shen, Tengming; Schwartz, Justin

    2016-02-02

    Understanding safe operating limits of composite superconducting wires is important for the design of superconducting magnets. Here we report measurements of quench-induced critical current density Jc degradation in commercial Ag/Bi2Sr2CaCu2Ox (Bi-2212) round wires using heater-induced quenches at 4.2 K in self magnetic field that reveal a general degradation behavior. Jc degradation strongly depends on the local hot spot temperature Tmax, and is nearly independent of operating current, the temperature gradient along the conductor dTmax/dx, and the temperature rising rate dTmax/dt. Both Jc and n value (where n is an index of the sharpness of the superconductor-to-normal transition) exhibit small butmore » irreversible degradation when Tmax exceeds 400-450 K, and large degradation occurs when Tmax exceeds 550 K. This behavior was consistently found for a series of Bi-2212 wires with widely variable wire architectures and porosity levels in the Bi-2212 filaments, including a wire processed using a standard partial melt processing and in which Bi-2212 filaments are porous, an overpressure processed wire in which Bi-2212 filaments are nearly porosity-free and that has a Jc(4.2 K, self field) exceeding 8000 A/mm2, and a wire that has nearly no filament to filament bridges after reaction. Microstructural observations of degraded wires reveal cracks in the Bi-2212 filaments perpendicular to the wire axis, indicating that the quench-induced Ic degradation is primarily driven by strain. These results further suggest that the quench degradation temperature limit depends on the strain state of Bi-2212 filaments and this dependence shall be carefully considered when engineering a high-field Bi-2212 magnet.« less

  15. Quench degradation limit of multifilamentary Ag/Bi2Sr2CaCu2O x round wires

    NASA Astrophysics Data System (ADS)

    Ye, Liyang; Li, Pei; Shen, Tengming; Schwartz, Justin

    2016-03-01

    Understanding safe operating limits of composite superconducting wires is important for the design of superconducting magnets. Here we report measurements of quench-induced critical current density J c degradation in commercial Ag/Bi2Sr2CaCu2O x (Bi-2212) round wires using heater-induced quenches at 4.2 K in self magnetic field that reveal a general degradation behavior. J c degradation strongly depends on the local hot spot temperature T max, and is nearly independent of operating current, the temperature gradient along the conductor dT max/dx, and the temperature rising rate dT max/dt. Both J c and n value (where n is an index of the sharpness of the superconductor-to-normal transition) exhibit small but irreversible degradation when T max exceeds 400-450 K, and large degradation occurs when T max exceeds 550 K. This behavior was consistently found for a series of Bi-2212 wires with widely variable wire architectures and porosity levels in the Bi-2212 filaments, including a wire processed using a standard partial melt process and in which Bi-2212 filaments are porous, an overpressure processed wire in which Bi-2212 filaments are nearly porosity-free and that has a J c(4.2 K, self field) exceeding 8000 A mm-2, and a wire that has nearly no filament to filament bridges after reaction. Microstructural observations of degraded wires reveal cracks in the Bi-2212 filaments perpendicular to the wire axis, indicating that the quench-induced I c degradation is primarily driven by strain. These results further suggest that the quench degradation temperature limit depends on the strain state of Bi-2212 filaments and this dependence shall be carefully considered when engineering a high-field Bi-2212 magnet.

  16. Strain tolerant microfilamentary superconducting wire

    DOEpatents

    Finnemore, Douglas K.; Miller, Theodore A.; Ostenson, Jerome E.; Schwartzkopf, Louis A.; Sanders, Steven C.

    1993-02-23

    A strain tolerant microfilamentary wire capable of carrying superconducting currents is provided comprising a plurality of discontinuous filaments formed from a high temperature superconducting material. The discontinuous filaments have a length at least several orders of magnitude greater than the filament diameter and are sufficiently strong while in an amorphous state to withstand compaction. A normal metal is interposed between and binds the discontinuous filaments to form a normal metal matrix capable of withstanding heat treatment for converting the filaments to a superconducting state. The geometry of the filaments within the normal metal matrix provides substantial filament-to-filament overlap, and the normal metal is sufficiently thin to allow supercurrent transfer between the overlapped discontinuous filaments but is also sufficiently thick to provide strain relief to the filaments.

  17. 49 CFR 236.76 - Tagging of wires and interference of wires or tags with signal apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... with signal apparatus. 236.76 Section 236.76 Transportation Other Regulations Relating to... wires and interference of wires or tags with signal apparatus. Each wire shall be tagged or otherwise so... apparatus. Inspections and Tests; All Systems...

  18. 49 CFR 236.76 - Tagging of wires and interference of wires or tags with signal apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... with signal apparatus. 236.76 Section 236.76 Transportation Other Regulations Relating to... wires and interference of wires or tags with signal apparatus. Each wire shall be tagged or otherwise so... apparatus. Inspections and Tests; All Systems...

  19. 47 CFR 32.2321 - Customer premises wiring.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2321... 232, Station Connections, inside wiring subclass. (b) Embedded Customer Premises Wiring is...

  20. The Earth's Hot Spots.

    ERIC Educational Resources Information Center

    Vink, Gregory E.; And Others

    1985-01-01

    Hot spots are isolated areas of geologic activity where volcanic eruptions, earthquakes, and upwelling currents occur far from plate boundaries. These mantle plumes are relatively stable and crustal plates drift over them. The nature and location of hot spots (with particular attention to the Hawaiian Islands and Iceland) are discussed. (DH)

  1. Hot Spot at Yellowstone

    ERIC Educational Resources Information Center

    Dress, Abby

    2005-01-01

    Within this huge national park (over two million acres spread across Wyoming, Montana, and Idaho) are steaming geysers, hot springs, bubbling mudpots, and fumaroles, or steam vents. Drives on the main roads of Yellowstone take tourists through the major hot attractions, which also include Norris Geyser Basin, Upper and Lower Geyser Basin, West…

  2. In Situ Electrochemical Deposition of Microscopic Wires

    NASA Technical Reports Server (NTRS)

    Yun, Minhee; Myung, Nosang; Vasquez, Richard

    2005-01-01

    A method of fabrication of wires having micron and submicron dimensions is built around electrochemical deposition of the wires in their final positions between electrodes in integrated circuits or other devices in which the wires are to be used. Heretofore, nanowires have been fabricated by a variety of techniques characterized by low degrees of controllability and low throughput rates, and it has been necessary to align and electrically connect the wires in their final positions by use of sophisticated equipment in expensive and tedious post-growth assembly processes. The present method is more economical, offers higher yields, enables control of wire widths, and eliminates the need for post-growth assembly. The wires fabricated by this method could be used as simple electrical conductors or as transducers in sensors. Depending upon electrodeposition conditions and the compositions of the electroplating solutions in specific applications, the wires could be made of metals, alloys, metal oxides, semiconductors, or electrically conductive polymers. In this method, one uses fabrication processes that are standard in the semiconductor industry. These include cleaning, dry etching, low-pressure chemical vapor deposition, lithography, dielectric deposition, electron-beam lithography, and metallization processes as well as the electrochemical deposition process used to form the wires. In a typical case of fabrication of a circuit that includes electrodes between which microscopic wires are to be formed on a silicon substrate, the fabrication processes follow a standard sequence until just before the fabrication of the microscopic wires. Then, by use of a thermal SiO-deposition technique, the electrodes and the substrate surface areas in the gaps between them are covered with SiO. Next, the SiO is electron-beam patterned, then reactive-ion etched to form channels having specified widths (typically about 1 m or less) that define the widths of the wires to be formed. Drops

  3. 6. HOT AIR PORTION OF DAMPERS. Hot Springs National ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. HOT AIR PORTION OF DAMPERS. - Hot Springs National Park, Bathhouse Row, Lamar Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  4. Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes

    DOEpatents

    Thomas, G.; Ahn, J.H.; Kim, N.J.

    1986-10-28

    An improved, energy efficient, hot rolling method for direct production of cold formable dual-phase steel is provided. The steel is heated to completely austenitize it and then continuously hot rolled and cooled down into the ferrite-austenite two phase region to a temperature which is just below the effective Ar[sub 3] temperature. The hot rolled steel is then rapidly quenched to provide an alloy containing strong, tough lath martensite (fibers) in a ductile soft ferrite matrix. The method is particularly useful for providing rods in which form the alloy is capable of being drawn into high strength wire or the like in a cold drawing operation without any intermediate annealing or patenting, and has excellent strength, ductility and fatigue characteristics. 3 figs.

  5. Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes

    DOEpatents

    Thomas, Gareth; Ahn, Jae-Hwan; Kim, Nack-Joon

    1986-01-01

    An improved, energy efficient, hot rolling method for direct production of cold formable dual-phase steel is provided. The steel is heated to completely austenitize it and then continuously hot rolled and cooled down into the ferrite-austenite two phase region to a temperature which is just below the effective Ar.sub.3 temperature. The hot rolled steel is then rapidly quenched to provide an alloy containing strong, tough lath martensite (fibers) in a ductile soft ferrite matrix. The method is particularly useful for providing rods in which form the alloy is capable of being drawn into high strength wire or the like in a cold drawing operation without any intermediate annealing or patenting, and has excellent strength, ductility and fatigue characteristics.

  6. Development of a precision wire feeder for small-diameter wire

    SciTech Connect

    Brandon, E.D.

    1995-03-01

    At Sandia National Laboratories in Albuquerque, the author designed and fabricated a precision wire feeder to be used with high energy density (electron beam and laser beam) welding for weld joints where filler wire might be needed to fill a gap or to adjust the chemical composition so that a crack-free weld could be made. The wire feeder incorporates a 25,000 step-per-revolution motor to power a urethane-coated drive roll. A microprocessor-based controller provides precise control of the motor and allows both continuous and pulsed feeding of the wire. A unidirectional 0.75-in.-dia ball bearing is used to press the wire against the drive roll. A slight constant backward tension is maintained on the wire spool by a Bodine torque motor. A Teflon tube is used to guide the wire from the drive roll to the vicinity of the weld, where a hypodermic needle is used to aim the wire into the weld pool. The operation of the wire feeder was demonstrated by feeding a 10-mil-dia, Type 304 stainless steel wire into a variety of CO{sub 2} laser beam welds. The resulting welds are smooth and continuous, and the welds are considered to be completely satisfactory for a variety of applications.

  7. Wire Crimp Termination Verification Using Ultrasonic Inspection

    NASA Technical Reports Server (NTRS)

    Perey, Daniel F.; Cramer, K. Elliott; Yost, William T.

    2007-01-01

    The development of a new ultrasonic measurement technique to quantitatively assess wire crimp terminations is discussed. The amplitude change of a compressional ultrasonic wave propagating through the junction of a crimp termination and wire is shown to correlate with the results of a destructive pull test, which is a standard for assessing crimp wire junction quality. Various crimp junction pathologies such as undercrimping, missing wire strands, incomplete wire insertion, partial insulation removal, and incorrect wire gauge are ultrasonically tested, and their results are correlated with pull tests. Results show that the nondestructive ultrasonic measurement technique consistently (as evidenced with destructive testing) predicts good crimps when ultrasonic transmission is above a certain threshold amplitude level. A physics-based model, solved by finite element analysis, describes the compressional ultrasonic wave propagation through the junction during the crimping process. This model is in agreement within 6% of the ultrasonic measurements. A prototype instrument for applying this technique while wire crimps are installed is also presented. The instrument is based on a two-jaw type crimp tool suitable for butt-splice type connections. Finally, an approach for application to multipin indenter type crimps will be discussed.

  8. LANSCE wire scanning diagnostics device mechanical design

    SciTech Connect

    Rodriguez Esparza, Sergio

    2010-01-01

    The Los Alamos Neutron Science Center (LANSCE) is one of the major experimental science facilities at the Los Alamos National Laboratory (LANL). The core of LANSCE's work lies in the operation of a powerful linear accelerator, which accelerates protons up to 84% the speed oflight. These protons are used for a variety of purposes, including materials testing, weapons research and isotopes production. To assist in guiding the proton beam, a series of over one hundred wire scanners are used to measure the beam profile at various locations along the half-mile length of the particle accelerator. A wire scanner is an electro-mechanical device that moves a set of wires through a particle beam and measures the secondary emissions from the resulting beam-wire interaction to obtain beam intensity information. When supplemented with data from a position sensor, this information is used to determine the cross-sectional profile of the beam. This measurement allows beam operators to adjust parameters such as acceleration, beam steering, and focus to ensure that the beam reaches its destination as effectively as possible. Some of the current wire scanners are nearly forty years old and are becoming obsolete. The problem with current wire scanners comes in the difficulty of maintenance and reliability. The designs of these wire scanners vary making it difficult to keep spare parts that would work on all designs. Also many of the components are custom built or out-dated technology and are no longer in production.

  9. In-Situ Wire Damage Detection System

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Roberson, Luke; Tate, Lanetra; Smith, Trent; Gibson, Tracy; Medelius, Pedro; Jolley, Scott

    2012-01-01

    An In-Situ Wire Damage Detection System (ISWDDS) has been developed that is capable of detecting damage to a wire insulation, or a wire conductor, or to both. The system will allow for realtime, continuous monitoring of wiring health/integrity and reduce the number of false negatives and false positives while being smaller, lighter in weight, and more robust than current systems. The technology allows for improved safety and significant reduction in maintenance hours for aircraft, space vehicles, satellites, and other critical high-performance wiring systems for industries such as energy production and mining. The integrated ISWDDS is comprised of two main components: (1) a wire with an innermost core conductor, an inner insulation film, a conductive layer or inherently conductive polymer (ICP) covering the inner insulation film, an outermost insulation jacket; and (2) smart connectors and electronics capable of producing and detecting electronic signals, and a central processing unit (CPU) for data collection and analysis. The wire is constructed by applying the inner insulation films to the conductor, followed by the outer insulation jacket. The conductive layer or ICP is on the outer surface of the inner insulation film. One or more wires are connected to the CPU using the smart connectors, and up to 64 wires can be monitored in real-time. The ISWDDS uses time domain reflectometry for damage detection. A fast-risetime pulse is injected into either the core conductor or conductive layer and referenced against the other conductor, producing transmission line behavior. If either conductor is damaged, then the signal is reflected. By knowing the speed of propagation of the pulse, and the time it takes to reflect, one can calculate the distance to and location of the damage.

  10. Bright Core-Shell Semiconductor Quantum Wires

    PubMed Central

    Liu, Yi-Hsin; Wang, Fudong; Hoy, Jessica; Wayman, Virginia L.; Steinberg, Lindsey K.; Loomis, Richard A.; Buhro, William E.

    2012-01-01

    Colloidal CdTe quantum wires are reported having ensemble photoluminescence efficiencies as high as 25% under low excitation-power densities. High photoluminescence efficiencies are achieved by formation of a monolayer CdS shell on the CdTe quantum wires. Like other semiconductor nanowires, the CdTe quantum wires may contain frequent wurtzite–zinc-blende structural alternations along their lengths. The present results demonstrate that the optical properties, emission-peak shape and photoluminescence efficiencies, are independent of the presence or absence of such structural alternations. PMID:23095017

  11. Colloidally deposited nanoparticle wires for biophysical detection

    NASA Astrophysics Data System (ADS)

    Shen, Sophie C.; Liu, Wen-Tao; Diao, Jia-Jie

    2015-12-01

    Among the techniques developed to prepare nanoparticle wires for multiple applications, the colloidal deposition method at interface has been regarded as cost-efficient and eco-friendly, and hence has attracted an increasing amount of research attention. In this report, the recent developments in preparing nanoparticle wires and integrated nanoparticle wire arrays using this technique have been reviewed. Furthermore, we have also discussed the application of these nanoparticle structures in detecting chemical and biological molecules. Project supported by the Fundamental Research Funds for the Central Universities through Xi’an Jiaotong University and the National Key Basic Research Program of China (Grant No. 2015CB856304).

  12. Pulse speed on a plucked wire

    NASA Astrophysics Data System (ADS)

    Odekirk, Tristan; Slaton, William V.

    2012-04-01

    This paper serves to update an elegant experiment published in The Physics Teacher to measure the speed of a pulse on a taut metal wire. Unfortunately, commercially available units2 that serve the same purpose are priced outside the range of most high school or college physics teaching laboratories. Wakeland et al. show how an affordable adaptation of the traditional standing wave apparatus using taut metal wire and horseshoe magnets can be used to measure the speed of a pulse by using an oscilloscope to measure an induced voltage in the wire as the pulse transverses the middle of the magnets, which are a known distance apart.

  13. Detectors Ensure Function, Safety of Aircraft Wiring

    NASA Technical Reports Server (NTRS)

    2013-01-01

    Pedro Medelius waited patiently in his lab at Kennedy Space Center. He had just received word that a colleague was bringing over a cable from a Space Shuttle solid rocket booster to test Medelius new invention. Medelius was calm until his colleague arrived, with about 30 other people. "Talk about testing under pressure," says Medelius. "There were people there from the Navy, the Air Force, and the Federal Aviation Administration." After the group s arrival, Medelius took a deep breath and connected his Standing Wave Reflectometer (SWR) to the cable. He wiggled the cable around, and the display showed a fault (a short or open circuit in wire) about an inch and a half inside the connector on the cable. His colleague questioned the results, because he had already checked that area on the cable. Medelius used the SWR to check again but got the same result. "That is when we took the cable apart and looked inside," Medelius says. "Lo and behold, that was exactly where the fault was." The impetus for Medelius new wire inspection technology came about in 1999 when one of the space shuttles lost power due to a fault somewhere in its more than 200 miles of electrical wiring. "The backup circuit was activated and prevented a major dysfunction, but nevertheless, there was a problem with the wiring," Medelius describes. Even though technicians used a device called a multimeter to measure the electrical current to find which wire had a fault, it could not pinpoint exactly where on the wire the fault was located. For that, technicians had to visually inspect the wire. "Sometimes they would have to remove the whole wire assembly and visually inspect every single wire. It was a very tedious operation because the wires are behind cabinets. They go all over the place in the shuttle," says Medelius. "NASA needed an instrument capable of telling them exactly where the faults were occurring." To meet NASA s needs for a highly precise device to inspect electrical power bundles, wires

  14. Copper Wire Bonding Concerns and Best Practices

    NASA Astrophysics Data System (ADS)

    Chauhan, Preeti; Zhong, Z. W.; Pecht, Michael

    2013-08-01

    Copper wire bonding of microelectronic parts has developed as a means to cut the costs of using the more mature technology of gold wire bonding. However, with this new technology, changes in the bonding processes as well as bonding metallurgy can affect product reliability. This paper discusses the challenges associated with copper wire bonding and the solutions that the industry has been implementing. The paper also provides information to enable customers to conduct qualification and reliability tests on microelectronic packages to facilitate adoption in their target applications.

  15. Resonant Anderson localization in segmented wires.

    PubMed

    Estarellas, Cristian; Serra, Llorenç

    2016-03-01

    We discuss a model of random segmented wire, with linear segments of two-dimensional wires joined by circular bends. The joining vertices act as scatterers on the propagating electron waves. The model leads to resonant Anderson localization when all segments are of similar length. The resonant behavior is present with one and also with several propagating modes. The probability distributions evolve from diffusive to localized regimes when increasing the number of segments in a similar way for long and short localization lengths. As a function of the energy, a finite segmented wire typically evolves from localized to diffusive to ballistic behavior in each conductance plateau.

  16. Fabrication of FFTF fuel pin wire wrap

    SciTech Connect

    Epperson, E.M.

    1980-06-01

    Lateral spacing between FFTF fuel pins is required to provide a passageway for the sodium coolant to flow over each pin to remove heat generated by the fission process. This spacing is provided by wrapping each fuel pin with type 316 stainless steel wire. This wire has a 1.435mm (0.0565 in.) to 1.448mm (0.0570 in.) diameter, contains 17 +- 2% cold work and was fabricated and tested to exacting RDT Standards. About 500 kg (1100 lbs) or 39 Km (24 miles) of fuel pin wrap wire is used in each core loading. Fabrication procedures and quality assurance tests are described.

  17. Telephone wire is backbone of security system

    SciTech Connect

    Brede, K.; Rackson, L.T.

    1995-09-01

    Video provides a variety of low-cost, high-quality solutions in today`s security environment. Cost-conscious managers of power generation stations, casinos, prison facilities, military bases and office buildings are considering using regular telephone wire (unshielded twisted pair-UTP) within their existing systems as the backbone of a video to the PC, personal and video-conferencing and training are other areas where phone wire in a building can save money and provide an alternative to coax or fiber for video. More and more, businesses and government agencies are meeting their needs efficiently by using telephone wires for more than just telephones.

  18. Total recall: an update on orthodontic wires.

    PubMed

    Jyothikiran, H; Shantharaj, Ravi; Batra, Panchali; Subbiah, Pradeep; Lakshmi, Bhagya; Kudagi, Vishal

    2014-01-01

    Orthodontic therapy is a force management procedure largely based on use of arch wires for storing and distributing biologically tolerable forces by means of which position of teeth is altered. Advances in material science and technology has resulted in an array of newer arch wire materials, opening new vistas, in orthodontic treatment. Materials with widely diverging properties are in the market today and their usage has profound implications on appliance mechanics, and are very much different from stainless steel which is popular even today. The dentists who practise orthodontics have to therefore clearly outline the phases of treatment and select the arch wire most suited for attaining specific treatment goals.

  19. Chemically etched modulation in wire radius for wire array Z-pinch perturbation studies

    SciTech Connect

    Jones, B.; Deeney, C.; McKenney, J.L.; Garrity, J.E.; Lobley, D.K.; Martin, K.L.; Griego, A.E.; Ramacciotti, J.P.; Bland, S.N.; Lebedev, S.V.; Bott, S.C.; Ampleford, D.J.; Palmer, J.B.A.; Rapley, J.; Hall, G.

    2004-11-01

    A technique for manufacturing wires with imposed modulation in radius with axial wavelengths as short as 1 mm is presented. Extruded aluminum 5056 with 15 {mu}m diameter was masked and chemically etched to reduce the radius by {approx}20% in selected regions. Characterized by scanning electron microscopy, the modulation in radius is a step function with a {approx}10 {mu}m wide conical transition between thick and thin segments, with some pitting in etched regions. Techniques for mounting and aligning these wires in arrays for fast z-pinch experiments will be discussed. Axially mass-modulated wire arrays of this type will allow the study of seeded Rayleigh-Taylor instabilities in z pinches, corona formation, wire initiation with varying current density in the wire core, and correlation of perturbations between adjacent wires. This tool will support magnetohydrodynamics code validation in complex three-dimensional geometries, and perhaps x-ray pulse shaping.

  20. Power and Energy of Exploding Wires

    NASA Astrophysics Data System (ADS)

    Valancius, Cole

    2015-06-01

    Exploding wires are used in many high-energy applications, such as initiating explosives. Analysis of gold wire burst in detonator applications has shown Burst Current and Action metrics to be incapable of explaining burst phenomenon as the inductance of a firing circuit is changed. Energy Density better captures the correlation between different wire geometries, different electrical inputs, and explosive initiation. This idea has been expanded upon, to analyze the burst properties in Power-Energy space. Further inconsistencies in the understanding of wire burst and its relation to peak voltage have been found. An argument will be made for redefining the definition of burst. The result is a more broad understanding of rapid metal phase transition and the physical applications of the released shock wave.