Science.gov

Sample records for additional field measurements

  1. Seismic Absorption and Modulus Measurements in Porous Rocks in Lab and Field: Physical, Chemical, and Biological Effects of Fluids (Detecting a Biosurfactant Additive in a Field Irrigation Experiment)

    SciTech Connect

    Spetzler, Hartmut

    2006-05-01

    We have been exploring a new technology that is based on using low-frequency seismic attenuation data to monitor changes in fluid saturation conditions in two-fluid phase porous materials. The seismic attenuation mechanism is related to the loss of energy due to the hysteresis of resistance to meniscus movement (changes in surface tension, wettability) when a pore containing two fluids is stressed at very low frequencies (< 10 Hz). This technology has potential applications to monitoring changes in (1) leakage at buried waste sites, (2) contaminant remediation, and (3) flooding during enhanced petroleum recovery. We have concluded a three year field study at the Maricopa Agricultural Center site of the University of Arizona. Three sets of instruments were installed along an East-West line perpendicular to the 50m by 50m inigation site. Each set of instruments consisted of one three component seismometer and one tiltmeter. Microseisms and solid Earth-tides served as strain sources. The former have a power peak at a period of about 6 seconds and the tides have about two cycles per day. Installation of instruments commenced in late summer of 2002. The instruments operated nearly continuously until April 2005. During the fall of 2003 the site was irrigated with water and one year later with water containing 150 ppm of a biosurfactant additive. This biodegradable additive served to mimic a class of contaminants that change the surface tension of the inigation fluid. Tilt data clearly show tidal tilts superimposed on local tilts due to agricultural irrigation and field work. When the observed signals were correlated with site specific theoretical tilt signals we saw no anomalies for the water irrigation in 2003, but large anomalies on two stations for the surfactant irrigation in 2004. Occasional failures of seismometers as well as data acquisition systems contributed to less than continuous coverage. These data are noisier than the tilt data, but do also show possible

  2. Undulator Field Integral Measurements

    SciTech Connect

    Wolf, Zachary

    2010-12-07

    The LCLS undulator field integrals must be very small so that the beam trajectory slope and offset stay within tolerance. In order to make accurate measurements of the small field integrals, a long coil will be used. This note describes the design of the coil measurement system.

  3. DEMONSTRATION PLAN FIELD MEASUREMENT ...

    EPA Pesticide Factsheets

    The demonstration of innovative field measurement devices for total petroleum hydrocarbons (TPH) in soil is being conducted under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation Program in June 2000 at the Navy Base Ventura County site in Port Hueneme, California. The primary purpose of the demonstration is to evaluate innovative field measurement devices for TPH in soil based on their performance and cost as compared to a conventional, off-site laboratory analytical method. The seven field measurement devices listed below will be demonstrated. CHEMetrics, Inc.'s, RemediAidTm Total Petroleum Hydrocarbon Starter Kit Wilks Enterprise, Inc.'s, Infracal' TOG/TPH Analyzer, Models CVH and HATR-T Horiba Instruments, Incorporated's, OCMA-350 Oil Content Analyzer Dexsil' Corporation's PetroFLAGTm Hydrocarbon Test Kit for Soil Environmental Systems Corporation's Synchronous Scanning Luminoscope siteLAB@ Corporation's Analytical Test Kit UVF-3 I OOA Strategic Diagnostics, Inc.'s, EnSys Petro Test System This demonstration plan describes the procedures that will be used to verify the performance and cost of each field measurement device. The plan incorporates the quality assurance and quality control elements needed to generate data of sufficient quality to document each device's performance and cost. A separate innovative technology verification report (ITVR) will be prepared for each device. The ITVRs will present the demonstratio

  4. 40 CFR 412.47 - Additional measures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Additional measures. 412.47 Section 412.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY Swine, Poultry, and...

  5. 40 CFR 412.47 - Additional measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Additional measures. 412.47 Section 412.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY Swine, Poultry, and...

  6. 40 CFR 412.47 - Additional measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Additional measures. 412.47 Section 412.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY Swine, Poultry, and...

  7. Measurement of radiofrequency fields

    SciTech Connect

    Leonowich, J.A.

    1992-05-01

    We are literally surrounded by radiofrequency (RFR) and microwave radiation, from both natural and man-made sources. The identification and control of man-made sources of RFR has become a high priority of radiation safety professionals in recent years. For the purposes of this paper, we will consider RFR to cover the frequencies from 3 kHz to 300 MHz, and microwaves from 300 MHz to 300 GHz, and will use the term RFR interchangeably to describe both. Electromagnetic radiation and field below 3 kHz is considered Extremely Low Frequency (ELF) and will not be discussed in this paper. Unlike x- and gamma radiation, RFR is non-ionizing. The energy of any RFR photon is insufficient to produce ionizations in matter. The measurement and control of RFR hazards is therefore fundamentally different from ionizing radiation. The purpose of this paper is to acquaint the reader with the fundamental issues involved in measuring and safely using RFR fields. 23 refs.

  8. Measurement of Helmholtz wave fields

    PubMed

    Alonso

    2000-07-01

    A simple formalism is found for the measurement of wave fields that satisfy the Helmholtz equation in free space. This formalism turns out to be analogous to the well-known theory of measurements for quantum-mechanical wave functions: A measurement corresponds to the squared magnitude of the inner product (in a suitable Hilbert space) of the wave field and a field that is associated with the detector. The measurement can also be expressed as an overlap in phase space of a special form of the Wigner function that is tailored for Helmholtz wave fields.

  9. Measuring Earth's Magnetic Field Simply.

    ERIC Educational Resources Information Center

    Stewart, Gay B.

    2000-01-01

    Describes a method for measuring the earth's magnetic field using an empty toilet paper tube, copper wire, clear tape, a battery, a linear variable resistor, a small compass, cardboard, a protractor, and an ammeter. (WRM)

  10. Measurements of magnetic field alignment

    SciTech Connect

    Kuchnir, M.; Schmidt, E.E.

    1987-11-06

    The procedure for installing Superconducting Super Collider (SSC) dipoles in their respective cryostats involves aligning the average direction of their field with the vertical to an accuracy of 0.5 mrad. The equipment developed for carrying on these measurements is described and the measurements performed on the first few prototypes SSC magnets are presented. The field angle as a function of position in these 16.6 m long magnets is a characteristic of the individual magnet with possible feedback information to its manufacturing procedure. A comparison of this vertical alignment characteristic with a magnetic field intensity (by NMR) characteristic for one of the prototypes is also presented. 5 refs., 7 figs.

  11. Near Field Antenna Measurement System.

    DTIC Science & Technology

    1982-03-01

    beam pointing accuracy and .6 dB gain accuracy. These antennas are both planar arrays with the X-band antenna scanning with ferrite phase shifters in...AD-A114 125 M[ES AIRCRAFT CO FULLERTON CA F/ 17/9 NEAR FIELD ANTENNA MEASUREMENT SYSTEM. (U) MAR 82 A E HOLLEY DAABO7-7?-C-1 87 UNCLASSIFIED NL...IllIHE El. onhEnoh IIIIhh --h h I~m I I Research and Development Technical Report I DAABO7-77-C-0587-F1 NEAR FIELD ANTENNA I MEASUREMENT SYSTEM I A.E

  12. Additive CHARMM force field for naturally occurring modified ribonucleotides.

    PubMed

    Xu, You; Vanommeslaeghe, Kenno; Aleksandrov, Alexey; MacKerell, Alexander D; Nilsson, Lennart

    2016-04-15

    More than 100 naturally occurring modified nucleotides have been found in RNA molecules, in particular in tRNAs. We have determined molecular mechanics force field parameters compatible with the CHARMM36 all-atom additive force field for all these modifications using the CHARMM force field parametrization strategy. Emphasis was placed on fine tuning of the partial atomic charges and torsion angle parameters. Quantum mechanics calculations on model compounds provided the initial set of target data, and extensive molecular dynamics simulations of nucleotides and oligonucleotides in aqueous solutions were used for further refinement against experimental data. The presented parameters will allow for computational studies of a wide range of RNAs containing modified nucleotides, including the ribosome and transfer RNAs.

  13. Additive CHARMM force field for naturally occurring modified ribonucleotides

    PubMed Central

    Xu, You; Vanommeslaeghe, Kenno; Aleksandrov, Alexey; MacKerell, Alexander D.

    2016-01-01

    More than 100 naturally occurring modified nucleotides have been found in RNA molecules, in particular in tRNAs. We have determined molecular mechanics force field parameters compatible with the CHARMM36 all‐atom additive force field for all these modifications using the CHARMM force field parametrization strategy. Emphasis was placed on fine tuning of the partial atomic charges and torsion angle parameters. Quantum mechanics calculations on model compounds provided the initial set of target data, and extensive molecular dynamics simulations of nucleotides and oligonucleotides in aqueous solutions were used for further refinement against experimental data. The presented parameters will allow for computational studies of a wide range of RNAs containing modified nucleotides, including the ribosome and transfer RNAs. © 2016 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc. PMID:26841080

  14. Additional electric field in real trench MOS barrier Schottky diode

    NASA Astrophysics Data System (ADS)

    Mamedov, R. K.; Aslanova, A. R.

    2016-04-01

    In real trench MOS barrier Schottky diode (TMBS diode) additional electric field (AEF) the whole is formed in the near contact region of the semiconductor and its propagation space is limited with the barrier metal and the metallic electrodes of MOS structures. Effective potential barrier height TMBS diode is formed via resulting electric field of superposition AEF and electric field of space charge region (SCR) semiconductor. The dependence of the resulting electric field intensity of the distance towards the inside the semiconductor is nonlinear and characterized by a peak at a certain distance from the interface. The thickness of the SCR in TMBS diode becomes equal to the trench depth. Force and energy parameters of the AEF, and thus resulting electric field in the SCR region, become dependent on the geometric design parameters TMBS diode. The forward I-V characteristic TMBS diode is described by the thermionic emission theory as in conventional flat Scottky diode, and in the reverse bias, current is virtually absent at initial voltage, appears abruptly at a certain critical voltage.

  15. Field measurement of ventilation rates.

    PubMed

    Persily, A K

    2016-02-01

    Ventilation rates have significant impacts on building energy use and indoor contaminant concentrations, making them key parameters in building performance. Ventilation rates have been measured in buildings for many decades, and there are mature measurement approaches available to researchers and others who need to know actual ventilation rates in buildings. Despite the fact that ventilation rates are critical in interpreting indoor concentration measurements, it is disconcerting how few Indoor Air Quality field studies measure ventilation rates or otherwise characterize the ventilation design of the study building(s). This paper summarizes parameters of interest in characterizing building ventilation, available methods for quantifying these parameters, and challenges in applying these methods to different types of buildings and ventilation systems. These parameters include whole-building air change rates, system outdoor air intake rates, and building infiltration rates. Tracer gas methods are reviewed as well as system airflow rate measurements using, for example, duct traverses. Several field studies of ventilation rates conducted over the past 75 years are described to highlight the approaches employed and the findings obtained.

  16. Rotating Capacitor Measures Steady Electric Fields

    NASA Technical Reports Server (NTRS)

    Johnston, A. R.; Kirkham, H.; Eng, B.

    1986-01-01

    Portable sensor measures electric fields created by dc powerlines or other dc-high-voltage sources. Measures fields from 70 to 50,000 V/m with linearity of 2 percent. Sensor used at any height above ground. Measures both magnitude and direction of field and provides signals representing these measurements to remote readout device. Sensor functions with minimal disturbance of field it is measuring.

  17. Classical field approach to quantum weak measurements.

    PubMed

    Dressel, Justin; Bliokh, Konstantin Y; Nori, Franco

    2014-03-21

    By generalizing the quantum weak measurement protocol to the case of quantum fields, we show that weak measurements probe an effective classical background field that describes the average field configuration in the spacetime region between pre- and postselection boundary conditions. The classical field is itself a weak value of the corresponding quantum field operator and satisfies equations of motion that extremize an effective action. Weak measurements perturb this effective action, producing measurable changes to the classical field dynamics. As such, weakly measured effects always correspond to an effective classical field. This general result explains why these effects appear to be robust for pre- and postselected ensembles, and why they can also be measured using classical field techniques that are not weak for individual excitations of the field.

  18. Field measurements involve various techniques

    SciTech Connect

    Moore, D.P.; Byars, H.G. )

    1990-07-30

    A number of field techniques are available to determine the extent of corrosion on production equipment. This article on oil field corrosion explains the use of corrosion coupons, several types of probes, and various inspection techniques, and shows how to monitor iron content in water.

  19. Chapter A6. Field Measurements

    USGS Publications Warehouse

    Wilde, Franceska D.; Radtke, Dean B.

    1998-01-01

    The National Field Manual for the Collection of Water-Quality Data (National Field Manual) provides guidelines and standard procedures for U.S. Geological Survey (USGS) personnel who collect data used to assess the quality of the Nation's surface-water and ground-water resources. Chapter A6 presents procedures and guidelines for the collection of data on air and water temperature, and on dissolved-oxygen concentrations, specific electrical conductance, pH, reduction-oxidation potential, alkalinity, and turbidity in water. Each chapter of the National Field Manual is published separately and revised periodically. Newly published and revised chapters are posted on the World Wide Web on the USGS page 'National Field Manual for the Collection of Water-Quality Data.' The URL for this page is http://pubs.water.usgs.gov/twri9A (accessed August 6, 2005).

  20. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  1. Livestock poisoning from oil field drilling fluids, muds and additives.

    PubMed

    Edwards, W C; Gregory, D G

    1991-10-01

    The use and potential toxicity of various components of oil well drilling fluids, muds and additives are presented. Many components are extremely caustic resulting in rumenitis. Solvent and petroleum hydrocarbon components may cause aspiration pneumonia and rumen dysfunction. Some additives cause methemoglobinemia. The most frequently encountered heavy metals are lead, chromium, arsenic, lithium and copper. Considerations for investigating livestock poisoning cases and several typical cases are reviewed.

  2. Livestock poisoning from oil field drilling fluids, muds and additives

    SciTech Connect

    Edwards, W.C.; Gregory, D.G. )

    1991-10-01

    The use and potential toxicity of various components of oil well drilling fluids, muds and additives are presented. Many components are extremely caustic resulting in rumenitis. Solvent and petroleum hydrocarbon components may cause aspiration pneumonia and rumen dysfunction. Some additives cause methemoglobinemia. The most frequently encountered heavy metals are lead, chromium, arsenic, lithium and copper. Considerations for investigating livestock poisoning cases and several typical cases are reviewed.

  3. Erosion by Wind: Field Measurement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind erosion and deposition results when wind moves soil from a bare susceptible surface to another location downwind. Although placement of permanent vertical references such as pins or rods has been used to measure soil redistribution, it is more commonly measured by capturing sediment moving dur...

  4. Magnetostatic Surface Field Measurement Facility.

    DTIC Science & Technology

    1986-12-01

    8217*. . - .J ., TV el VV TV - UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE REPORT DOCUMENTATION PA~a El la REPCRT SECURITY CLASSIFICAT ION lb...0 10 -YW 977 the sI;eroid relative to the incident magnetic field, it is convenient to cons’der seoarately the cases when H- z = 0 and Hi z = 1

  5. Porosity Measurements and Analysis for Metal Additive Manufacturing Process Control

    PubMed Central

    Slotwinski, John A; Garboczi, Edward J; Hebenstreit, Keith M

    2014-01-01

    Additive manufacturing techniques can produce complex, high-value metal parts, with potential applications as critical metal components such as those found in aerospace engines and as customized biomedical implants. Material porosity in these parts is undesirable for aerospace parts - since porosity could lead to premature failure - and desirable for some biomedical implants - since surface-breaking pores allows for better integration with biological tissue. Changes in a part’s porosity during an additive manufacturing build may also be an indication of an undesired change in the build process. Here, we present efforts to develop an ultrasonic sensor for monitoring changes in the porosity in metal parts during fabrication on a metal powder bed fusion system. The development of well-characterized reference samples, measurements of the porosity of these samples with multiple techniques, and correlation of ultrasonic measurements with the degree of porosity are presented. A proposed sensor design, measurement strategy, and future experimental plans on a metal powder bed fusion system are also presented. PMID:26601041

  6. Porosity Measurements and Analysis for Metal Additive Manufacturing Process Control.

    PubMed

    Slotwinski, John A; Garboczi, Edward J; Hebenstreit, Keith M

    2014-01-01

    Additive manufacturing techniques can produce complex, high-value metal parts, with potential applications as critical metal components such as those found in aerospace engines and as customized biomedical implants. Material porosity in these parts is undesirable for aerospace parts - since porosity could lead to premature failure - and desirable for some biomedical implants - since surface-breaking pores allows for better integration with biological tissue. Changes in a part's porosity during an additive manufacturing build may also be an indication of an undesired change in the build process. Here, we present efforts to develop an ultrasonic sensor for monitoring changes in the porosity in metal parts during fabrication on a metal powder bed fusion system. The development of well-characterized reference samples, measurements of the porosity of these samples with multiple techniques, and correlation of ultrasonic measurements with the degree of porosity are presented. A proposed sensor design, measurement strategy, and future experimental plans on a metal powder bed fusion system are also presented.

  7. Modeling Errors in Daily Precipitation Measurements: Additive or Multiplicative?

    NASA Technical Reports Server (NTRS)

    Tian, Yudong; Huffman, George J.; Adler, Robert F.; Tang, Ling; Sapiano, Matthew; Maggioni, Viviana; Wu, Huan

    2013-01-01

    The definition and quantification of uncertainty depend on the error model used. For uncertainties in precipitation measurements, two types of error models have been widely adopted: the additive error model and the multiplicative error model. This leads to incompatible specifications of uncertainties and impedes intercomparison and application.In this letter, we assess the suitability of both models for satellite-based daily precipitation measurements in an effort to clarify the uncertainty representation. Three criteria were employed to evaluate the applicability of either model: (1) better separation of the systematic and random errors; (2) applicability to the large range of variability in daily precipitation; and (3) better predictive skills. It is found that the multiplicative error model is a much better choice under all three criteria. It extracted the systematic errors more cleanly, was more consistent with the large variability of precipitation measurements, and produced superior predictions of the error characteristics. The additive error model had several weaknesses, such as non constant variance resulting from systematic errors leaking into random errors, and the lack of prediction capability. Therefore, the multiplicative error model is a better choice.

  8. Comparing Laboratory and Field Measured Bioaccumulation Endpoints

    EPA Science Inventory

    The report presents an approach that allows comparisons of all laboratory and field bioaccumulation endpoints measurements. The approach will enable the inclusion of large amounts of field data into evaluations of bioaccumulation potential for legacy chemicals. Currently, these...

  9. Measurements of Solar Vector Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J. (Editor)

    1985-01-01

    Various aspects of the measurement of solar magnetic fields are presented. The four major subdivisions of the study are: (1) theoretical understanding of solar vector magnetic fields; (3) techniques for interpretation of observational data; and (4) techniques for data display.

  10. NASA-JSC antenna near-field measurement system

    NASA Technical Reports Server (NTRS)

    Cooke, W. P.; Friederich, P. G.; Jenkins, B. M.; Jameson, C. R.; Estrada, J. P.

    1988-01-01

    Work was completed on the near-field range control software. The capabilities of the data processing software were expanded with the addition of probe compensation. In addition, the user can process the measured data from the same computer terminal used for range control. The design of the laser metrology system was completed. It provides precise measruement of probe location during near-field measurements as well as position data for control of the translation beam and probe cart. A near-field range measurement system was designed, fabricated, and tested.

  11. The Measurement of Magnetic Fields

    ERIC Educational Resources Information Center

    Berridge, H. J. J.

    1973-01-01

    Discusses five experimental methods used by senior high school students to provide an accurate calibration curve of magnet current against the magnetic flux density produced by an electromagnet. Compares the relative merits of the five methods, both as measurements and from an educational viewpoint. (JR)

  12. Measuring electric fields from surface contaminants with neutral atoms

    SciTech Connect

    Obrecht, J. M.; Wild, R. J.; Cornell, E. A.

    2007-06-15

    In this paper we demonstrate a technique of utilizing magnetically trapped neutral {sup 87}Rb atoms to measure the magnitude and direction of stray electric fields emanating from surface contaminants. We apply an alternating external electric field that adds to (or subtracts from) the stray field in such a way as to resonantly drive the trapped atoms into a mechanical dipole oscillation. The growth rate of the oscillation's amplitude provides information about the magnitude and sign of the stray field gradient. Using this measurement technique, we are able to reconstruct the vector electric field produced by surface contaminants. In addition, we can accurately measure the electric fields generated from adsorbed atoms purposely placed onto the surface and account for their systematic effects, which can plague a precision surface-force measurement. We show that baking the substrate can reduce the electric fields emanating from adsorbate and that the mechanism for reduction is likely surface diffusion, not desorption.

  13. Measurement of vortex flow fields

    NASA Technical Reports Server (NTRS)

    Mcdevitt, T. Kevin; Ambur, Todd A.; Orngard, Gary M.; Owen, F. Kevin

    1992-01-01

    A 3-D laser fluorescence anemometer (LFA) was designed, built, and demonstrated for use in the Langley 16 x 24 inch Water Tunnel. Innovative optical design flexibility combined with compact and portable data acquisition and control systems were incorporated into the instrument. This will allow its use by NASA in other test facilities. A versatile fiber optic system facilities normal and off-axis laser beam alignment, removes mirror losses and improves laser safety. This added optical flexibility will also enable simple adaptation for use in the adjacent jet facility. New proprietary concepts in transmitting color separation, light collection, and novel prism separation of the scattered light was also designed and built into the system. Off-axis beam traverse and alignment complexity led to the requirement for a specialized, programmable transverse controller, and the inclusion of an additional traverse for the off-axis arm. To meet this challenge, an 'in-house' prototype unit was designed and built and traverse control software developed specifically for the water tunnel traverse applications. A specialized data acquisition interface was also required. This was designed and built for the LFA system.

  14. Magnetic Field Response Measurement Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Taylor, Bryant D.; Shams, Qamar A.; Fox, Robert L.

    2005-01-01

    A measurement acquisition method that alleviates many shortcomings of traditional measurement systems is presented in this paper. The shortcomings are a finite number of measurement channels, weight penalty associated with measurements, electrical arcing, wire degradations due to wear or chemical decay and the logistics needed to add new sensors. The key to this method is the use of sensors designed as passive inductor-capacitor circuits that produce magnetic field responses. The response attributes correspond to states of physical properties for which the sensors measure. A radio frequency antenna produces a time-varying magnetic field used to power the sensor and receive the magnetic field response of the sensor. An interrogation system for discerning changes in the sensor response is presented herein. Multiple sensors can be interrogated using this method. The method eliminates the need for a data acquisition channel dedicated to each sensor. Methods of developing magnetic field response sensors and the influence of key parameters on measurement acquisition are discussed.

  15. Relation between near field and far field acoustic measurements

    NASA Technical Reports Server (NTRS)

    Bies, D. A.; Scharton, T. D.

    1974-01-01

    Several approaches to the problem of determining the far field directivity of an acoustic source located in a reverberant environment, such as a wind tunnel, are investigated analytically and experimentally. The decrease of sound pressure level with distance is illustrated; and the spatial extent of the hydrodynamic and geometric near fields, the far field, and the reverberant field are described. A previously-prosposed analytical technique for predicting the far field directivity of the acoustic source on the basis of near field data is investigated. Experiments are conducted with small acoustic sources and an analysis is performed to determine the variation with distance from the source of the directionality of the sound field. A novel experiment is conducted in which the sound pressure measured at various distances from an acoustic driver located in the NASA Ames 40 x 80 ft wind tunnel is crosscorrelated with the driver excitation voltage.

  16. FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN ...

    EPA Pesticide Factsheets

    Metorex's X-MET 2000 X-ray fluorescence analyzer was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003, at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration was to collect reliable performance and cost data for the X-MET 2000 and four other field measurement devices for mercury in soil and sediment. The key objectives of the Demonstration were: 1) determine sensitivity of each instrument with respect to a vendor-generated method detection limit (MDL) and practical quantitation limit (POL); 2) determine analytical accuracy associated with vendor field measurements using field samples and standard reference materials; 3) evaluate the precision of vendor field measurements; 4) measure time required to perform mercury measurements; and 5) estimate costs associated with mercury measurements for capital, labor, supplies, and investigation-derived wastes. The Demonstration involved analysis of standard reference materials (SRMs), field samples collected from four sites, and spiked field samples for mercury .The performance results for a given field measurement device were compared to those for an off-site laboratory reference method,

  17. FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN ...

    EPA Pesticide Factsheets

    Milestone's Direct Mercury Analyzer (DMA-80) was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003 at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration was to collect reliable performance and cost data for the DMA-80 and four other field measurement devices for mercury in soil and sediment. The key objectives of the demonstration were: 1) determine sensitivity of each instrument with respect to a vendor-generated method detection limit (MDL) and practical quantitation limit (POL); 2) determine analytical accuracy associated with vendor field measurements using field samples and standard reference materials (SRMs); 3) evaluate the precision of vendor field measurements; 4) measure time required to perform mercury measurements; and 5) estimate costs associated with mercury measurements for capital, labor, supplies, and investigation-derived wastes. The demonstration involved analysis of standard reference materials (SRMs ), field samples collected from four sites, and spiked field samples for mercury. The performance results for a given field measurement device were compared to those for an off-site laboratory using reference method,

  18. FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN ...

    EPA Pesticide Factsheets

    NITON's XL-700 Series X-ray fluorescence analyzers were demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003 at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration was to collect reliable performance and cost data for the XLi 702 and XU 792 and four other field measurement devices for mercury in soil and sediment. The key objectives of the Demonstration were: 1) determine sensitivity of each instrument with respect to a vendor-generated method detection limit (MDL) and practical quantitation limit (POL); 2) determine analytical accuracy associated with vendor field measurements using field samples and standard reference materials; 3) evaluate the precision of vendor field measurements; 4) measure time required to perform mercury measurements; and 5) estimate costs associated with mercury measurements for capital, labor, supplies, and investigation-derived wastes. The Demonstration involved analysis of standard reference materials (SRMs), field samples collected from four sites, and spiked field samples for mercury. The performance results for a given field measurement device were compared to those for an off-site laboratory reference method,

  19. FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN ...

    EPA Pesticide Factsheets

    Ohio Lumex's RA915+/91 C mercury analyzer was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003, at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration was to collect reliable performance and cost data for the RA915+/91C and four other field measurement devices for mercury in soil and sediment. The key objectives of the Demonstration were: 1) determine sensitivity of each instrument with respect to a vendor-generated method detection limit (MDL) and practical quantitation limit (POL); 2) determine analytical accuracy associated with vendor field measurements using field samples and standard reference materials; 3) evaluate the precision of vendor field measurements; 4) measure time required to perform mercury measurements; and 5) estimate costs associated with mercury measurements for capital, labor, supplies, and investigation-derived wastes. The Demonstration also involved analysis of standard reference materials (SRMs), field samples collected from four sites, and spiked field samples for mercury. The performance results for a given field measurement device were compared to those for an off-site laboratory using reference method,

  20. MAGNETIC FIELD MEASUREMENTS FOR FAST-CHANGING MAGNETIC FIELDS.

    SciTech Connect

    JAIN, A.; ESCALLIER, J.; GANETIS, G.; LOUIE, W.; MARONE, A.; THOMAS. R.; WANDERER, P.

    2004-10-03

    Several recent applications for fast ramped magnets have been found that require rapid measurement of the field quality during the ramp. (In one instance, accelerator dipoles will be ramped at 1 T/sec, with measurements needed to the accuracy typically required for accelerators.) We have built and tested a new type of magnetic field measuring system to meet this need. The system consists of 16 stationary pickup windings mounted on a cylinder. The signals induced in the windings in a changing magnetic field are sampled and analyzed to obtain the field harmonics. To minimize costs, printed circuit boards were used for the pickup windings and a combination of amplifiers and ADPs used for the voltage readout system. New software was developed for the analysis. Magnetic field measurements of a model dipole developed for the SIS200 accelerator at GSI are presented. The measurements are needed to insure that eddy currents induced by the fast ramps do not impact the field quality needed for successful accelerator operation.

  1. Attracting Students to the Field of Measurement

    ERIC Educational Resources Information Center

    Finney, Sara J.; Pastor, Dena A.

    2012-01-01

    To address the shortage of professionals in measurement, it is essential that we make young career-seekers aware that measurement is an option as a profession. In this paper, we discuss how creating a strong pipeline of students into our field involves personal interactions between faculty representing the graduate programs in measurement and…

  2. FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN ...

    EPA Pesticide Factsheets

    Monitoring Technologies International Pty. Ltd. (MTI) has developed a Portable Digital Voltammeter (PDV) designed to identify and measure the concentration of heavy metal ions. MTI's PDV 6000 was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in June 2003 in Las Vegas, Nevada. The purpose of the Demonstration was to collect reliable performance and cost data for the PDV 6000. Four other field measurement devices for mercury in soil and sediment were evaluated in May 2003 at the Oak Ridge National Laboratory in Oak Ridge, Tennessee. The key objectives of the Demonstration were: 1) determine sensitivity of each instrument with respect to a vendor-generated method detection limit (MDL) and practical quantitation limit (PQL); 2) determine potential analytical accuracy associated with vendor field measurements; 3) evaluate the precision of vendor field measurements; 4) measure time required to perform mercury measurements; and 5) estimate costs associated with mercury measurements for capital, labor, supplies, and investigation-derived wastes (IDW). The Demonstration also involved analysis of standard reference materials (SRMs), field samples collected from four sites, and spiked field samples for mercury. The performance results for a given field measurement device were compared to those for an off-site laboratory using reference method,

  3. Cleaning and Cleanliness Measurement of Additive Manufactured Parts

    NASA Technical Reports Server (NTRS)

    Welker, Roger W.; Mitchell, Mark A.

    2015-01-01

    The successful acquisition and utilization of piece parts and assemblies for contamination sensitive applications requires application of cleanliness acceptance criteria. Contamination can be classified using many different schemes. One common scheme is classification as organic, ionic and particulate contaminants. These may be present in and on the surface of solid components and assemblies or may be dispersed in various gaseous or liquid media. This discussion will focus on insoluble particle contamination on the surface of piece parts and assemblies. Cleanliness of parts can be controlled using two strategies, referred to as gross cleanliness and precision cleanliness. Under a gross cleanliness strategy acceptance is based on visual cleanliness. This approach introduces a number of concerns that render it unsuitable for controlling cleanliness of high technology products. Under the precision cleanliness strategy, subjective, visual assessment of cleanliness is replaced by objective measurement of cleanliness. When a precision cleanliness strategy is adopted there naturally arises the question: How clean is clean enough? The six commonly used methods for establishing objective cleanliness acceptance limits will be discussed. Special emphasis shall focus on the use of multiple extraction, a technique that has been demonstrated for additively manufactured parts.

  4. Effect of Mg or Ag addition on the evaporation field of Al.

    PubMed

    Aruga, Yasuhiro; Nako, Hidenori; Tsuneishi, Hidemasa; Hasegawa, Yuki; Tao, Hiroaki; Ichihara, Chikara; Serizawa, Ai

    2013-09-01

    It is known that the distribution of the charge-states as well as the evaporation field shift to higher values as the specimen temperature is decreased at a constant rate of evaporation. This study has explored the effect of Mg or Ag addition on the evaporation field of Al in terms of the charge state distribution of the field evaporated Al ions. The fractional abundance of Al(2+) ions with respect to the total Al ions in Al-Mg alloy is lower than that in pure Al, whereas it shows higher level in the Al-Ag alloy at lower temperatures. The temperature dependence of the fractional abundance of Al(2+) ions has been also confirmed, suggesting that Al atoms in the Al-Mg alloy need lower evaporation field, while higher field is necessary to evaporate Al atoms in the Al-Ag alloy, compared with pure Al. This tendency is in agreement with that of the evaporation fields estimated theoretically by means of measurements of the work function and calculations of the binding energy of the pure Al, Al-Mg and Al-Ag alloys.

  5. MICE Spectrometer Solenoid Magnetic Field Measurements

    SciTech Connect

    Leonova, M.

    2013-09-01

    The Muon Ionization Cooling Experiment (MICE) is designed to demonstrate ionization cooling in a muon beam. Its goal is to measure a 10% change in transverse emittance of a muon beam going through a prototype Neutrino Factory cooling channel section with an absolute measurement accuracy of 0.1%. To measure emittances, MICE uses two solenoidal spectrometers, with Solenoid magnets designed to have 4 T fields, uniform at 3 per mil level in the tracking volumes. Magnetic field measurements of the Spectrometer Solenoid magnet SS2, and analysis of coil parameters for input into magnet models will be discussed.

  6. Magnetic space-based field measurements

    NASA Technical Reports Server (NTRS)

    Langel, R. A.

    1981-01-01

    Because the near Earth magnetic field is a complex combination of fields from outside the Earth of fields from its core and of fields from its crust, measurements from space prove to be the only practical way to obtain timely, global surveys. Due to difficulty in making accurate vector measurements, early satellites such as Sputnik and Vanguard measured only the magnitude survey. The attitude accuracy was 20 arc sec. Both the Earth's core fields and the fields arising from its crust were mapped from satellite data. The standard model of the core consists of a scalar potential represented by a spherical harmonics series. Models of the crustal field are relatively new. Mathematical representation is achieved in localized areas by arrays of dipoles appropriately located in the Earth's crust. Measurements of the Earth's field are used in navigation, to map charged particles in the magnetosphere, to study fluid properties in the Earth's core, to infer conductivity of the upper mantels, and to delineate regional scale geological features.

  7. Field Measurement of Head Related Transfer Functions

    DTIC Science & Technology

    1990-04-01

    HEAD RELATED TRANSFER FUNCTIONS FREDERIC WIGHTMAN, Ph.D. DORIS J. KISTLER, Ph.D. HEARING DEVELOPMENT... function , F the free-field to eardrum transfer function (sometimes called the head - related transfer function , or HRTF), and M the microphone transfer ...into three areas: 1) acoustical measurements of free-field-to-eardrum transfer functions (also called head -relaLed transfer functions , or

  8. Magnetic Field Response Measurement Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Taylor,Bryant D.; Shams, Qamar A.; Fox, Robert L.

    2007-01-01

    This paper presents a measurement acquisition method that alleviates many shortcomings of traditional measurement systems. The shortcomings are a finite number of measurement channels, weight penalty associated with measurements, electrical arcing, wire degradations due to wear or chemical decay and the logistics needed to add new sensors. Wire degradation has resulted in aircraft fatalities and critical space launches being delayed. The key to this method is the use of sensors designed as passive inductor-capacitor circuits that produce magnetic field responses. The response attributes correspond to states of physical properties for which the sensors measure. Power is wirelessly provided to the sensing element by using Faraday induction. A radio frequency antenna produces a time-varying magnetic field used to power the sensor and receive the magnetic field response of the sensor. An interrogation system for discerning changes in the sensor response frequency, resistance and amplitude has been developed and is presented herein. Multiple sensors can be interrogated using this method. The method eliminates the need for a data acquisition channel dedicated to each sensor. The method does not require the sensors to be near the acquisition hardware. Methods of developing magnetic field response sensors and the influence of key parameters on measurement acquisition are discussed. Examples of magnetic field response sensors and the respective measurement characterizations are presented. Implementation of this method on an aerospace system is discussed.

  9. Magnetospheric electric field measurements during sudden commencements

    NASA Technical Reports Server (NTRS)

    Aggson, T. L.; Skillman, T. L.

    1973-01-01

    Direction measurements of electric fields were made in the outer magnetosphere during two sudden commencements in 1972. These measurements were observed with the double floating probe experiment carried aboard the IMP 6 satellite. The initial variations of the measured electric field consisted of an increase from a background of about 1 mv/meter to some 10 mv/meter at about 7 rE (earth radi) and to some 4 mv/meter at 3 rE. These initial electric field disturbances were longitudinal, oriented counter clockwise about an axis pointed north. A solution of Maxwell's third equation is derived for these measurements using a quasi-static version of Mead's model of the magnetosphere B (t). This solution seems to describe well the magnitude and direction of the initial perturbation of the electric field vectors observed during these two sudden commencements. After the initial increase, the measured electric field rings several times with periods of the order of minutes. This observed oscillatory behavior correlates with magnetic observatory records taken near the foot of the magetic field line passing through the satellite.

  10. Field measurement of cotton seedling evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information on cotton evapotranspiration (ET) during the seedling growth stage and under field conditions is scarce because ET is a difficult parameter to measure. Our objective was to use weighable lysimeters to measure daily values of cotton seedling ET. We designed and built plastic weighable mic...

  11. Electric Field and Density Measurements with STEREO-SWaves.

    NASA Astrophysics Data System (ADS)

    Kellogg, P. J.; Goetz, K.; Monson, S. J.; Bale, S. D.; Maksimovic, M.

    2007-12-01

    The STEREO experiment SWaves has a low frequency part which is designed to make measurements of low frequency electric fields and rapid measurements of density fluctuations, using the three 6 meter stacer monopole antennas. The short antennas of STEREO respond both to density fluctuations and to electric fields. Therefore, it is desired to obtain four quantities, density and 3 components of electric field, from three measurements, the potentials on the three orthogonal antennas relative to the spacecraft, which requires some additional information. One possibility is to add a fourth equation implied by the large plasma conductivity, so large that electric field parallel to the magnetic field is zero, a condition which has often been used in electric field measurements. Under selected conditions, this seems to work. There are also conditions, for example ion acoustic waves, where the responses to density fluctuations and to electric fields are available from dispersion relations, and this provides another possible solution. A situation where it is not likely that the parallel electric field is zero is the case of solitary, intense bursts of Langmuir waves. For this case, it is expected that there is an electron density depression due to the ponderomotive pressure, and a resulting low frequency electric field from the non-neutrality which would be expected to have components parallel to the magnetic field. Examples will be discussed.

  12. Velocity field measurements of a laminar starting plume

    NASA Astrophysics Data System (ADS)

    Tanny, J.; Shlien, D. J.

    1985-04-01

    The region of buoyant fluid resulting from the initiation of heating of an infinite fluid is called the starting plume. Here, velocity field measurements of this flow pattern are presented for the first time. The measurements were carried out by processing digitized tracer particle path photographs. Similarity of the velocity field of the starting plume as it rises was found to exist in the limited range of heat injection rates investigated. The vorticity computed from the velocity field was diffuse, there being no evidence of a distinctive core. Additional flow visualization experiments show the spiral structure in the starting plume cap.

  13. Wind Field Measurements With Airborne Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Menzies, Robert T.

    1999-01-01

    In collaboration with lidar atmospheric remote sensing groups at NASA Marshall Space Flight Center and National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratory, we have developed and flown the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) lidar on the NASA DC-8 research aircraft. The scientific motivations for this effort are: to obtain measurements of subgrid scale (i.e. 2-200 km) processes and features which may be used to improve parameterizations in global/regional-scale models; to improve understanding and predictive capabilities on the mesoscale; and to assess the performance of Earth-orbiting Doppler lidar for global tropospheric wind measurements. MACAWS is a scanning Doppler lidar using a pulsed transmitter and coherent detection; the use of the scanner allows 3-D wind fields to be produced from the data. The instrument can also be radiometrically calibrated and used to study aerosol, cloud, and surface scattering characteristics at the lidar wavelength in the thermal infrared. MACAWS was used to study surface winds off the California coast near Point Arena, with an example depicted in the figure below. The northerly flow here is due to the Pacific subtropical high. The coastal topography interacts with the northerly flow in the marine inversion layer, and when the flow passes a cape or point that juts into the winds, structures called "hydraulic expansion fans" are observed. These are marked by strong variation along the vertical and cross-shore directions. The plots below show three horizontal slices at different heights above sea level (ASL). Bottom plots are enlargements of the area marked by dotted boxes above. The terrain contours are in 200-m increments, with the white spots being above 600-m elevation. Additional information is contained in the original.

  14. Solar Implications of ULYSSES Interplanetary Field Measurements

    NASA Astrophysics Data System (ADS)

    Wang, Y.-M.; Sheeley, N. R., Jr.

    1995-07-01

    Recent observations by the Ulysses magnetometer team have shown that the strength of the radial interplanetary field component, |Br| , is essentially independent of latitude, a result which implies that the heliospheric currents are confined entirely to thin sheets. Using such a current sheet model, we extrapolate the observed photospheric field to 1 AU and compare the predicted magnitude and sign of Br with spacecraft measurements during 1970--1993. Approximate agreement can be obtained if the solar magnetograph measurements in the Fe I lambda 5250 line are scaled upward by a latitude-dependent factor, similar to that derived by Ulrich from a study of magnetic saturation effects. The correction factor implies sharply peaked polar fields near sunspot minimum, with each polar coronal hole having a mean field strength of 10 G.

  15. Magnetic Field Response Measurement Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E. (Inventor); Taylor, Bryant D. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, Christopher L. (Inventor); Fox, Melanie L. (Inventor); Bryant, Robert G. (Inventor)

    2006-01-01

    Magnetic field response sensors designed as passive inductor-capacitor circuits produce magnetic field responses whose harmonic frequencies correspond to states of physical properties for which the sensors measure. Power to the sensing element is acquired using Faraday induction. A radio frequency antenna produces the time varying magnetic field used for powering the sensor, as well as receiving the magnetic field response of the sensor. An interrogation architecture for discerning changes in sensor s response kequency, resistance and amplitude is integral to the method thus enabling a variety of measurements. Multiple sensors can be interrogated using this method, thus eliminating the need to have a data acquisition channel dedicated to each sensor. The method does not require the sensors to be in proximity to any form of acquisition hardware. A vast array of sensors can be used as interchangeable parts in an overall sensing system.

  16. System for controllable magnetic measurement with direct field determination

    NASA Astrophysics Data System (ADS)

    Stupakov, O.

    2012-02-01

    This work describes a specially designed setup for magnetic hysteresis and Barkhausen noise measurements. The setup combines two main elements: an improved fast algorithm to control the waveform of magnetic induction and simultaneous direct determination of the magnetic field. The digital feedback algorithm uses only the previous measurement cycle to correct the magnetization voltage without any additional correlation parameter; it usually converges after several tens of cycles. The magnetic field is measured at the sample surface using a vertically mounted array of sensitive Hall sensors. Linear extrapolation of the tangential field profile to the sample surface determines the true waveform of the magnetic field. This unique combination of physically based control for both parameters of the magnetization process provides stable and reliable results, which are independent of a specified experimental configuration. This is illustrated for the industrially attractive measurements of non-oriented electrical steels with a 50 Hz sinusoidal induction waveform.

  17. Infrared array measurements of sunspot magnetic fields

    NASA Astrophysics Data System (ADS)

    McPherson, M. R.; Lin, H.; Kuhn, J. R.

    1992-06-01

    A 128 x 128 format HgCdTl IR array has been used with the Sacramento Peak Observatory Vacuum Telescope (VTT) and echelle spectrograph to obtain two-dimensional observations of the true magnetic field strength in a sunspot. All of the spectral information contained in the unpolarized IR Fraunhofer line profile, with time resolution of about a minute is retained. Unlike previous optical observations (cf. Adam, 1990), observations readily allow direct field strength measurements out to the outer edge of the penumbra. The magnetic flux density in the outer penumbra is not well described by an extrapolation of the quadratic polynomial, in normalized central distance, that describes the umbral field.

  18. Stratospheric electric field measurements with transmediterranean balloons

    NASA Astrophysics Data System (ADS)

    de La Morena, B. A.; Alberca, L. F.; Curto, J. J.; Holzworth, R. H.

    1993-01-01

    The horizontal component of the stratospheric electric field was measured using a balloon in the ODISEA Campaign of Transmediterranean Balloon Program. The balloon flew between Trapani (Sicily) and El Arenosillo (Huelva, Spain) along the 39 deg N parallel at a height between 34 and 24 km. The high values found for the field on fair-weather and its quasi-turbulent variation, both in amplitude and direction, are difficult to explain with the classical electric field source. A new source, first described by Holzworth (1989), is considered as possibly causing them.

  19. Electric Field Quantitative Measurement System and Method

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R. (Inventor)

    2016-01-01

    A method and system are provided for making a quantitative measurement of an electric field. A plurality of antennas separated from one another by known distances are arrayed in a region that extends in at least one dimension. A voltage difference between at least one selected pair of antennas is measured. Each voltage difference is divided by the known distance associated with the selected pair of antennas corresponding thereto to generate a resulting quantity. The plurality of resulting quantities defined over the region quantitatively describe an electric field therein.

  20. Electric field measurements from Halley, Antarctica

    NASA Astrophysics Data System (ADS)

    Nicoll, Keri; Harrison, R. Giles

    2016-04-01

    Antarctica is a unique location for the study of atmospheric electricity. Not only is it one of the most pollutant free places on Earth, but its proximity to the south magnetic pole means that it is an ideal location to study the effects of solar variability on the atmospheric electric field. This is due to the reduced shielding effect of the geomagnetic field at the poles which leads to a greater flux of incoming Galactic Cosmic Rays (GCRs) as well as an increased probability of energetic particle precipitation from SEPs and relativistic electrons. To investigate such effects, two electric field mills of different design were installed at the British Antarctic Survey Halley base in February 2015 (75. 58 degrees south, 26.66 degrees west). Halley is situated on the Brunt Ice Shelf in the south east of the Weddell Sea and has snow cover all year round. Preliminary analysis has focused on selection of fair weather criteria using wind speed and visibility measurements which are vital to assess the effects of falling snow, blowing snow and freezing fog on the electric field measurements. When the effects of such adverse weather conditions are removed clear evidence of the characteristic Carnegie Curve diurnal cycle exists in the Halley electric field measurements (with a mean value of 50V/m and showing a 40% peak to peak variation in comparison to the 34% variation in the Carnegie data). Since the Carnegie Curve represents the variation in thunderstorm activity across the Earth, its presence in the Halley data confirms the presence of the global atmospheric electric circuit signal at Halley. The work presented here will discuss the details of the Halley electric field dataset, including the variability in the fair weather measurements, with a particular focus on magnetic field fluctuations.

  1. Performance of field measuring probes for SSC magnets

    SciTech Connect

    Thomas, R.; Ganetis, G.; Herrera, J.; Hogue, R.; Jain, A.; Louie, W.; Marone, A.; Wanderer, P.

    1993-12-31

    Several years of experience have been acquired on the operation of probes (``moles``) constructed for the measurement of the multipole components of the magnetic fields of SSC magnets. The field is measured by rotating coils contained in a 2.4-m long tube that is pulled through the aperture of the magnet by an external device-the transporter. In addition to the measuring coils, the tube contains motors for rotating the coil and a system for sensing local vertical using gravity sensors to provide an absolute reference for the field measurements. We describe the steps that must be taken in order to ensure accurate, repeatable measurements; the design changes that have been motivated by difficulties encountered (noise, vibration, variations in temperature); and other performance issues. The mechanical interface between the probe and the hewn tube of the magnet is also described.

  2. CHARMM additive and polarizable force fields for biophysics and computer-aided drug design

    PubMed Central

    Vanommeslaeghe, K.

    2014-01-01

    Background Molecular Mechanics (MM) is the method of choice for computational studies of biomolecular systems owing to its modest computational cost, which makes it possible to routinely perform molecular dynamics (MD) simulations on chemical systems of biophysical and biomedical relevance. Scope of Review As one of the main factors limiting the accuracy of MD results is the empirical force field used, the present paper offers a review of recent developments in the CHARMM additive force field, one of the most popular bimolecular force fields. Additionally, we present a detailed discussion of the CHARMM Drude polarizable force field, anticipating a growth in the importance and utilization of polarizable force fields in the near future. Throughout the discussion emphasis is placed on the force fields’ parametrization philosophy and methodology. Major Conclusions Recent improvements in the CHARMM additive force field are mostly related to newly found weaknesses in the previous generation of additive force fields. Beyond the additive approximation is the newly available CHARMM Drude polarizable force field, which allows for MD simulations of up to 1 microsecond on proteins, DNA, lipids and carbohydrates. General Significance Addressing the limitations ensures the reliability of the new CHARMM36 additive force field for the types of calculations that are presently coming into routine computational reach while the availability of the Drude polarizable force fields offers a model that is an inherently more accurate model of the underlying physical forces driving macromolecular structures and dynamics. PMID:25149274

  3. Additional studies for the spectrophotometric measurement of iodine in water

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Previous work in iodine spectroscopy is briefly reviewed. Continued studies of the direct spectrophotometric determination of aqueous iodine complexed with potassium iodide show that free iodine is optimally determined at the isosbestic point for these solutions. The effects on iodine determinations of turbidity and chemical substances (in trace amounts) is discussed and illustrated. At the levels tested, iodine measurements are not significantly altered by such substances. A preliminary design for an on-line, automated iodine monitor with eventual capability of operating also as a controller was analyzed and developed in detail with respect single beam colorimeter operating at two wavelengths (using a rotating filter wheel). A flow-through sample cell allows the instrument to operate continuously, except for momentary stop flow when measurements are made. The timed automatic cycling of the system may be interrupted whenever desired, for manual operation. An analog output signal permits controlling an iodine generator.

  4. Far-field errors due to random noise in cylindrical near-field measurements

    NASA Astrophysics Data System (ADS)

    Romeu, Jordi; Jofre, Luis; Cardama, Angel

    1992-01-01

    A full characterization of the far-field noise obtained from cylindrical near- to far-field transformation, for a white Gaussian, space stationary, near-field noise is derived. A possible source for such noise is the receiver additive noise. The noise characterization is done by obtaining the autocorrelation of the far-field noise, which is shown to be easily computed during the transformation process. Even for this simple case, the far-field noise has complex behavior dependent on the measurement probe. Once the statistical properties of the far-field noise are determined, it is possible to compute upper and lower bounds for the radiation pattern for a given probability. These bounds define a strip within the radiation pattern with the desired probability. This may be used as part of a complete near-field error analysis of a particular cylindrical near-field facility.

  5. Documents Similarity Measurement Using Field Association Terms.

    ERIC Educational Resources Information Center

    Atlam, El-Sayed; Fuketa, M.; Morita, K.; Aoe, Jun-ichi

    2003-01-01

    Discussion of text analysis and information retrieval and measurement of document similarity focuses on a new text manipulation system called FA (field association)-Sim that is useful for retrieving information in large heterogeneous texts and for recognizing content similarity in text excerpts. Discusses recall and precision, automatic indexing…

  6. Displacement field measurement in the nanometer range

    NASA Astrophysics Data System (ADS)

    Surrel, Yves; Fournier, Nicolas

    1996-09-01

    The grid method is a classical tool for displacement measurement, which provides field data. This method has benefited very much from the phase-shifting technique in recent years. Two examples of applications of this method in the nanometer range are presented. The first one concerns the materials science: it is shown that microgrids observed by SEM can provide displacement field data with an accuracy of a few nanometers. The second one concerns the measurement of a rigid-body displacement. In this case, displacement data can be averaged over the whole field, drastically increasing the sensitivity. It is shown that a sensitivity of 7 nm can be achieved by using a coarse grid with 8 lines per mm. This sensitivity corresponds to 1/18000 of the grid pitch.

  7. Magnetic Field Response Measurement Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodward, Stanley E. (Inventor); Taylor, Bryant D. (Inventor)

    2007-01-01

    Magnetic field response sensors designed as passive inductor- capacit or circuits produce magnetic field responses whose harmonic frequenci es correspond to states of physical properties for which the sensors measure. Power to the sensing element is acquired using Faraday induc tion. A radio frequency antenna produces the time varying magnetic fi eld used for powering the sensor, as well as receiving the magnetic field response of the sensor. An interrogation architecture for disce rning changes in sensor's response frequency, resistance and amplitud e is integral to the method thus enabling a variety of measurements. Multiple sensors can be interrogated using this method, thus eliminat ing the need to have a data acquisition channel dedicated to each se nsor. The method does not require the sensors to be in proximity to a ny form of acquisition hardware. A vast array of sensors can be used as interchangeable parts in an overall sensing system.

  8. LEM—electromagnetic fields measurement laboratory

    NASA Astrophysics Data System (ADS)

    Annino, A.; Falciglia, F.; Musumeci, F.; Oliveri, M.; Privitera, G.; Triglia, A.

    2000-04-01

    The widespread presence of electromagnetic waves and the relative problems regarding them have favored the constitution of the LEM at the DMFCI in Catania University, where competence has been developing in this sector for about 10 years. Full operativeness has been reached as far as the electromagnetic field measurements in anthropized environments are concerned. Other research will be undertaken as soon as further funds are available. Some problems connected with the perfecting of measurements instruments and the results of emission measurements of cellular telephones are presented.

  9. Rectangular subsonic jet flow field measurements

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Swan, David H.

    1990-01-01

    Flow field measurements of three subsonic rectangular cold air jets are presented. The three cases had aspect ratios of 1x2, 1x4 at a Mach number of 0.09 and an aspect ratio of 1x2 at a Mach number of 0.9. All measurements were made using a 3-D laser Doppler anemometer system. The data includes the mean velocity vector, all Reynolds stress tensor components, turbulent kinetic energy and velocity correlation coefficients. The data are presented in tabular and graphical form. No analysis of the measured data or comparison to other published data is made.

  10. Recommendations for field measurements of aircraft noise

    NASA Technical Reports Server (NTRS)

    Marsh, A. H.

    1982-01-01

    Specific recommendations for environmental test criteria, data acquisition procedures, and instrument performance requirements for measurement of noise levels produced by aircraft in flight are provided. Recommendations are also given for measurement of associated airplane and engine parameters and atmospheric conditions. Recommendations are based on capabilities which were available commercially in 1981; they are applicable to field tests of aircraft flying subsonically past microphones located near the surface of the ground either directly under or to the side of a flight path. Aircraft types covered by the recommendations include fixed-wing airplanes powered by turbojet or turbofan engines or by propellers. The recommended field-measurement procedures are consistent with assumed requirements for data processing and analysis.

  11. Improved visualization of flow field measurements

    NASA Technical Reports Server (NTRS)

    Miles, Jeffrey Hilton

    1991-01-01

    A capability was developed that makes it possible to apply to measured flow field data the visualization tools developed to display numerical solutions for computational fluid dynamic problems. The measurement monitor surface (MMS) procedure was applied to the analysis of flow field measurements within a low aspect ratio transonic axial flow fan rotor obtained with 2-D laser anemometry. The procedure generates input for the visualization tools developed to display numerical solutions for computational fluid dynamics problems. The relative Mach number contour plots obtained by this method resemble the conventional contour plots obtained by more traditional methods. The results show that the MMS procedure can be used to generate input for the multidimensional processing and analysis tools developed for data from numerical flow field simulations. They show that an experimenter can apply the MMS procedure to his data and then use an interactive graphics program to display scalar quantities like the Mach number by profiles, carpet plots, contour lines, and surfaces using various colors. Also, flow directionality can be shown by display of vector fields and particle traces.

  12. Cleaning and Cleanliness Measurement of Additive Manufactured Parts

    NASA Technical Reports Server (NTRS)

    Mitchell, Mark A.; Raley, Randy

    2016-01-01

    The successful acquisition and utilization of piece parts and assemblies for contamination sensitive applications requires application of cleanliness acceptance criteria. Contamination can be classified using many different schemes. One common scheme is classification as organic, ionic and particulate contaminants. These may be present in and on the surface of solid components and assemblies or may be dispersed in various gaseous or liquid media. This discussion will focus on insoluble particle contamination on the surfaces of piece parts and assemblies. Cleanliness of parts can be controlled using two strategies, referred to as gross cleanliness and precision cleanliness. Under a gross cleanliness strategy acceptance is based on visual cleanliness. This approach introduces a number of concerns that render it unsuitable for controlling cleanliness of high technology products. Under the precision cleanliness strategy, subjective, visual assessment of cleanliness is replaced by objective measurement of cleanliness. When a precision cleanliness strategy is adopted there naturally arises the question: How clean is clean enough? The methods for establishing objective cleanliness acceptance limits will be discussed.

  13. Electric Field Effects in RUS Measurements

    SciTech Connect

    Darling, Timothy W; Ten Cate, James A; Allured, Bradley; Carpenter, Michael A

    2009-09-21

    Much of the power of the Resonant Ultrasound Spectroscopy (RUS) technique is the ability to make mechanical resonance measurements while the environment of the sample is changed. Temperature and magnetic field are important examples. Due to the common use of piezoelectric transducers near the sample, applied electric fields introduce complications, but many materials have technologically interesting responses to applied static and RF electric fields. Non-contact optical, buffered, or shielded transducers permit the application of charge and externally applied electric fields while making RUS measurements. For conducting samples, in vacuum, charging produces a small negative pressure in the volume of the material - a state rarely explored. At very high charges we influence the electron density near the surface so the propagation of surface waves and their resonances may give us a handle on the relationship of electron density to bond strength and elasticity. Our preliminary results indicate a charge sign dependent effect, but we are studying a number of possible other effects induced by charging. In dielectric materials, external electric fields influence the strain response, particularly in ferroelectrics. Experiments to study this connection at phase transformations are planned. The fact that many geological samples contain single crystal quartz suggests a possible use of the piezoelectric response to drive vibrations using applied RF fields. In polycrystals, averaging of strains in randomly oriented crystals implies using the 'statistical residual' strain as the drive. The ability to excite vibrations in quartzite polycrystals and arenites is explored. We present results of experimental and theoretical approaches to electric field effects using RUS methods.

  14. Electric field effects in RUS measurements.

    PubMed

    Darling, Timothy W; Allured, Bradley; Tencate, James A; Carpenter, Michael A

    2010-02-01

    Much of the power of the Resonant Ultrasound Spectroscopy (RUS) technique is the ability to make mechanical resonance measurements while the environment of the sample is changed. Temperature and magnetic field are important examples. Due to the common use of piezoelectric transducers near the sample, applied electric fields introduce complications, but many materials have technologically interesting responses to applied static and RF electric fields. Non-contact optical, buffered, or shielded transducers permit the application of charge and externally applied electric fields while making RUS measurements. For conducting samples, in vacuum, charging produces a small negative pressure in the volume of the material--a state rarely explored. At very high charges we influence the electron density near the surface so the propagation of surface waves and their resonances may give us a handle on the relationship of electron density to bond strength and elasticity. Our preliminary results indicate a charge sign dependent effect, but we are studying a number of possible other effects induced by charging. In dielectric materials, external electric fields influence the strain response, particularly in ferroelectrics. Experiments to study this connection at phase transformations are planned. The fact that many geological samples contain single crystal quartz suggests a possible use of the piezoelectric response to drive vibrations using applied RF fields. In polycrystals, averaging of strains in randomly oriented crystals implies using the "statistical residual" strain as the drive. The ability to excite vibrations in quartzite polycrystals and arenites is explored. We present results of experimental and theoretical approaches to electric field effects using RUS methods.

  15. Electric field measurements with stratospheric balloons

    NASA Technical Reports Server (NTRS)

    Iversen, I. B.

    1989-01-01

    Electric fields and currents in the middle atmosphere are important elements of the modern picture of this region. Balloon instruments, reaching the level of the stratosphere, were used extensively for the experimental work. The research has shown good progress, both in the MAP period and in the years before and after. The knowledge was increased about, e.g., the upper atmosphere potential, the electric properties of the medium itself and about the coupling with magnetospheric (ionospheric) fields and currents. Also various measurements have brought about a discussion of the possible existence of hitherto unknown sources. Throughout the MAP period the work on a possible definition of an electric index has continued.

  16. Measurements of magnetic fields in solar prominences

    NASA Technical Reports Server (NTRS)

    Deglinnocenti, Egidio Landi

    1986-01-01

    Magnetic fields can be measured, in solar prominences, by means of two different basic mechanisms that are responsible for the introduction (or the reduction) of a given amount of polarization in spectral lines: these are the Zeeman effect and the Hanle effect. Through the splitting of the magnetic components of a spectral line, the Zeeman effect is capable of introducing a certain amount of circular polarization across the line profile. The Hanle effect consist of a modification of the linear polarization that is induced in spectral lines by the anisotropic illumination of the prominence plasma by the photospheric radiation field. These two effects are briefly discussed.

  17. Methyl bromide volatility measurements from treated fields

    SciTech Connect

    Majewski, M.S.; Woodrow, J.E.; Seiber, J.N. |

    1995-12-31

    Methyl bromide is used as an agricultural soil fumigant and concern is growing over the role it may play in the depletion of stratospheric ozone. Methyl bromide is applied using various techniques and little is known about how much of the applied fumigant volatilizes into the atmosphere after application. The post-application volatilization losses of methyl bromide from two fields using different application practices were measured using an aerodynamic-gradient technique. One field was covered with a high-barrier plastic film tarp during application and the other was left uncovered, but the furrows made by the injection shanks were bedded over. The cumulative volatilization losses from the tarped field were 22% of the nominal application within the first 5 days of the experiment and about 32% of the nominal application within 9 days including the one day after the tarp was removed on day 8. The nontarped field lost 89%of the nominal application by volatilization in 5 days. The error associated, with each flux measurement, as well as variations in daily flux losses with differing sampling period lengths show the degree of variability inherent in this type of study.

  18. Aerodynamic Flow Field Measurements for Automotive Systems

    NASA Technical Reports Server (NTRS)

    Hepner, Timothy E.

    1999-01-01

    The design of a modern automotive air handling system is a complex task. The system is required to bring the interior of the vehicle to a comfortable level in as short a time as possible. A goal of the automotive industry is to predict the interior climate of an automobile using advanced computational fluid dynamic (CFD) methods. The development of these advanced prediction tools will enable better selection of engine and accessory components. The goal of this investigation was to predict methods used by the automotive industry. To accomplish this task three separate experiments were performed. The first was a laboratory setup where laser velocimeter (LV) flow field measurements were made in the heating and air conditioning unit of a Ford Windstar. The second involved flow field measurements in the engine compartment of a Ford Explorer, with the engine running idle. The third mapped the flow field exiting the center dashboard panel vent inside the Explorer, while the circulating fan operated at 14 volts. All three experiments utilized full-coincidence three-component LV systems. This enabled the mean and fluctuating velocities to be measured along with the Reynolds stress terms.

  19. Ultrasound field measurement using a binary lens

    PubMed Central

    Clement, G.T.; Nomura, H.; Kamakura, T.

    2014-01-01

    Field characterization methods using a scattering target in the absence of a point-like receiver have been well described in which scattering is recorded by a relatively large receiver located outside the field of measurement. Unfortunately, such methods are prone to artifacts due to averaging across the receiver surface. To avoid this problem while simultaneously increasing the gain of a received signal, the present study introduces a binary plate lens designed to focus spherically-spreading waves onto a planar region having a nearly-uniform phase proportional to that of the target location. The lens is similar to a zone plate, but modified to produce a biconvex-like behavior, such that it focuses both planar and spherically spreading waves. A measurement device suitable for characterizing narrowband ultrasound signals in air is designed around this lens by coupling it to a target and planar receiver. A prototype device is constructed and used to characterize the field of a highly-focused 400 kHz air transducer along 2 radial lines. Comparison of the measurements with numeric predictions formed from nonlinear acoustic simulation showed good relative pressure correlation, with mean differences of 10% and 12% over center 3dB FWHM drop and 12% and 17% over 6dB. PMID:25643084

  20. Field-enhanced electrodes for additive-injection non-thermal plasma (NTP) processor

    DOEpatents

    Rosocha, Louis A.; Ferreri, Vincent; Kim, Yongho

    2009-04-21

    The present invention comprises a field enhanced electrode package for use in a non-thermal plasma processor. The field enhanced electrode package includes a high voltage electrode and a field-enhancing electrode with a dielectric material layer disposed in-between the high voltage electrode and the field-enhancing electrode. The field-enhancing electrode features at least one raised section that includes at least one injection hole that allows plasma discharge streamers to occur primarily within an injected additive gas.

  1. Rectangular subsonic jet flow field measurements

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Swan, David H.

    1989-01-01

    Flow field measurements are presented of 3 subsonic rectangular cold air jets. The 3 cases presented had aspect ratios of 1 x 2, 1 x 4 at a Mach number of 0.09 and an aspect ratio of 1 x 2 at a Mach number of 0.9. All measurements were made using a 3-D laser Doppler anemoneter system. The presented data includes the mean velocity vector, all Reynolds stress tensor components, turbulent kinetic energy and velocity correlation coefficients. The data is presented in tabular and graphical form. No analysis of the measured data or comparison to other published data is made. All tabular data are available in ASCII format on MS-DOS compatible disks.

  2. Measurements of Photospheric and Chromospheric Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Lagg, Andreas; Lites, Bruce; Harvey, Jack; Gosain, Sanjay; Centeno, Rebecca

    2015-12-01

    The Sun is replete with magnetic fields, with sunspots, pores and plage regions being their most prominent representatives on the solar surface. But even far away from these active regions, magnetic fields are ubiquitous. To a large extent, their importance for the thermodynamics in the solar photosphere is determined by the total magnetic flux. Whereas in low-flux quiet Sun regions, magnetic structures are shuffled around by the motion of granules, the high-flux areas like sunspots or pores effectively suppress convection, leading to a temperature decrease of up to 3000 K. The importance of magnetic fields to the conditions in higher atmospheric layers, the chromosphere and corona, is indisputable. Magnetic fields in both active and quiet regions are the main coupling agent between the outer layers of the solar atmosphere, and are therefore not only involved in the structuring of these layers, but also for the transport of energy from the solar surface through the corona to the interplanetary space. Consequently, inference of magnetic fields in the photosphere, and especially in the chromosphere, is crucial to deepen our understanding not only for solar phenomena such as chromospheric and coronal heating, flares or coronal mass ejections, but also for fundamental physical topics like dynamo theory or atomic physics. In this review, we present an overview of significant advances during the last decades in measurement techniques, analysis methods, and the availability of observatories, together with some selected results. We discuss the problems of determining magnetic fields at smallest spatial scales, connected with increasing demands on polarimetric sensitivity and temporal resolution, and highlight some promising future developments for their solution.

  3. Electric Field Double Probe Measurements for Ionospheric Space Plasma Experiments

    NASA Technical Reports Server (NTRS)

    Pfaff, R.

    1999-01-01

    Double probes represent a well-proven technique for gathering high quality DC and AC electric field measurements in a variety of space plasma regimes including the magnetosphere, ionosphere, and mesosphere. Such experiments have been successfully flown on a variety of spacecraft including sounding rockets and satellites. Typical instrument designs involve a series of trades, depending on the science objectives, type of platform (e.g., spinning or 3-axis stabilized), expected plasma regime where the measurements will be made, available telemetry, budget, etc. In general, ionospheric DC electric field instruments that achieve accuracies of 0.1 mV/m or better, place spherical sensors at large distances (10m or more) from the spacecraft body in order to extend well beyond the spacecraft wake and sheath and to achieve large signal-to-noise ratios for DC and long wavelength measurements. Additional sets of sensors inboard of the primary, outermost sensors provide useful additional information, both for diagnostics of the plasma contact potentials, which particularly enhance the DC electric field measurements on non-spinning spacecraft, and for wavelength and phase velocity measurements that use the spaced receiver or "interferometer" technique. Accurate attitude knowledge enables B times V contributions to be subtracted from the measured potentials, and permits the measured components to be rotated into meaningful geophysical reference frames. We review the measurement technique for both DC and wave electric field measurements in the ionosphere discussing recent advances involving high resolution burst memories, multiple baseline double probes, new sensor surface materials, biasing techniques, and other considerations.

  4. Field and laboratory determination of a poly(vinyl/vinylidene chloride) additive in brick mortar.

    PubMed

    Law, S L; Newman, J H; Ptak, F L

    1990-02-01

    A polymerized vinyl/vinylidene chloride additive, used in brick mortar during the 60s and 70s, is detected at the building site by the field method, which employs a commercially available chloride test strip. The field test results can then be verified by the laboratory methods. In one method, total chlorine in the mortar is determined by an oxygen-bomb method and the additive chloride is determined by difference after water-soluble chlorides have been determined on a separate sample. In the second method, the polymerized additive is extracted directly from the mortar with tetrahydrofuran (THF). The difference in weight before and after extraction of the additive gives the weight of additive in the mortar. Evaporation of the THF from the extract leaves a thin film of the polymer, which gives an infrared "fingerprint" spectrum characteristic of the additive polymer.

  5. Field measurements in unwadeable natural hydraulic jumps

    NASA Astrophysics Data System (ADS)

    Valle, B.; Pasternack, G.

    2003-04-01

    Recent research in fluvial geomorphology has emphasized the development and application of digital terrain models to better understand process-form relations. However, field measurements in mountain channels have largely been restricted to low velocity or ephemeral flow conditions. To address this problem, a new high-resolution mechanical surveying system was developed at UC Davis and used to measure the 3D bed and water surface topographies of an unwadeable plunging hydraulic jump in the Cache Creek basin, CA. Labeled as the River Truss, the system is capable of making high-resolution form and process measurements over a 30 to 115 m2 area. Bed and water surface DTMs were derived from the field data using AutoCAD. River Truss precision was assessed by DTM differencing the hydraulic jump bed surface topography with a DTM developed from tacheometric survey at low base flows. Bed surface DTMs indicate significant spatial complexity of the underlying bed step in the supercritical flow region and significant downstream bed scour. Water surface DTMs indicate 3D complexity of the plunging flow surface and divergence from 1D free-fall theory. Further study will emphasize the development and deployment of process-based instrumentation such that the complex turbulent air-water flow dynamics associated with natural hydraulic jumps may be better understood. Also, a second generation River Truss that has a larger coverage area and automated data collection has been designed and is now being built.

  6. Addition of Digital Breast Tomosynthesis to Full-Field Digital Mammography in the Diagnostic Setting: Additional Value and Cancer Detectability

    PubMed Central

    Seo, Mirinae; Kim, Sun Ah; Kim, Won Hwa; Lim, Ji He; Lee, Su Hyun; Bae, Min Sun; Koo, Hye Ryoung; Cho, Nariya; Moon, Woo Kyung

    2016-01-01

    Purpose The purpose of this study was to assess the value of adding digital breast tomosynthesis (DBT) to full-field digital mammography (FFDM) in the diagnostic workup of breast cancer and to determine which lesion variables affect cancer detectability in the combined modality. Methods Between March and May 2012, paired FFDM and DBT images were obtained from 203 women as part of a diagnostic workup for breast cancer. Images from FFDM alone, DBT alone, and DBT combined with FFDM were reviewed in separate sessions by six blinded readers. Jackknife alternative free-response receiver operating characteristic (JAFROC) figure of merit (FOM), sensitivity, and specificity were compared between the modalities. Lesion characteristics affecting the cancer detection rate when using the combined modality were also analyzed. Results Among the 203 women, 126 women had a total of 129 malignancies and 77 women had total of 77 benign lesions. The overall JAFROC FOM of the combined modality was higher than that of FFDM alone (0.827 vs. 0.775, p<0.001) and that of DBT alone was higher than that of FFDM alone (0.807 vs. 0.775, p=0.027). The overall sensitivity of the combined modality was higher than that of FFDM alone (80.0% vs. 73.2%, p<0.001) and that of DBT alone was higher than that of FFDM alone (78.3% vs. 73.2%, p=0.007). Compared to FFDM alone, the combined modality detected an additional 48 cancers. Using the combined modality, the presence of masses or microcalcifications was significantly associated with the cancer detection rate (p<0.001). Conclusion The combination of DBT with FFDM results in a higher diagnostic yield than FFDM alone. Additionally, DBT alone performs better than FFDM alone. However, even when DBT is combined with FFDM, breast cancers with no discernible masses and those lacking calcifications are difficult to detect. PMID:28053633

  7. Field Measurements of Black Carbon Yields from Gas Flaring.

    PubMed

    Conrad, Bradley M; Johnson, Matthew R

    2017-02-07

    Black carbon (BC) emissions from gas flaring in the oil and gas industry are postulated to have critical impacts on climate and public health, but actual emission rates remain poorly characterized. This paper presents in situ field measurements of BC emission rates and flare gas volume-specific BC yields for a diverse range of flares. Measurements were performed during a series of field campaigns in Mexico and Ecuador using the sky-LOSA optical measurement technique, in concert with comprehensive Monte Carlo-based uncertainty analyses. Parallel on-site measurements of flare gas flow rate and composition were successfully performed at a subset of locations enabling direct measurements of fuel-specific BC yields from flares under field conditions. Quantified BC emission rates from individual flares spanned more than 4 orders of magnitude (up to 53.7 g/s). In addition, emissions during one notable ∼24-h flaring event (during which the plume transmissivity dropped to zero) would have been even larger than this maximum rate, which was measured as this event was ending. This highlights the likely importance of superemitters to global emission inventories. Flare gas volume-specific BC yields were shown to be strongly correlated with flare gas heating value. A newly derived correlation fitting current field data and previous lab data suggests that, in the context of recent studies investigating transport of flare-generated BC in the Arctic and globally, impacts of flaring in the energy industry may in fact be underestimated.

  8. A Diagnostic for Electric Field Measurements in the Near/Far-Field Regions of ICRF Antenna

    NASA Astrophysics Data System (ADS)

    Martin, E. H.; Caughman, J. B. O.; Isler, R. C.

    2015-11-01

    The physics mechanisms of wave heating and current drive processes in the bulk hot plasma are generally well identified. However, details of the wave-plasma interaction with a material surface in the cold plasma edge are still not fully understood. The driver behind this interaction is the time-periodic wave electric field and is referred to as the near/far-field depending on the location with respect to the antenna. Various models have been formulated to capture the near/far-field physics but have not been tested experimentally. Thus, a diagnostic capable of measuring the electric field with temporal and 3D-spatial resolution is critical for confidence in the codes used to design next generation ICRF antennas. This research is focused on the development of a laser based spectroscopic technique, Doppler-free saturation spectroscopy (DFSS), and its implementation to study near/far-field physics. Using DFSS the spectra line profile of various electronic transitions are measured and fit to a quantum mechanical model incorporating both magnetic and dynamic electric field operators. The electric field direction and magnitude are extracted from the fit. The experimental setup and planned experiments will be discussed. Additionally, initial measurements of fitted Hδ spectrum under the influence of known electric and magnetic fields will be presented.

  9. Measuring exposed magnetic fields of welders in working time.

    PubMed

    Yamaguchi-Sekino, Sachiko; Ojima, Jun; Sekino, Masaki; Hojo, Minoru; Saito, Hiroyuki; Okuno, Tsutomu

    2011-01-01

    The assessment of the occupational electromagnetic field exposure of welders is of great importance, especially in shielded-arc welding, which uses relatively high electric currents of up to several hundred amperes. In the present study, we measured the magnetic field exposure level of welders in the course of working. A 3-axis Hall magnetometer was attached to a subject's wrist in order to place the sensor probe at the closest position to the magnetic source (a cable from the current source). Data was acquired every 5 s from the beginning of the work time. The maximum exposed field was 0.35-3.35 mT (Mean ± SD: 1.55 ± 0.93 mT, N=17) and the average value per day was 0.04-0.12 mT (Mean ± SD: 0.07 ± 0.02 mT, N=17). We also conducted a finite element method-based analysis of human hand tissue for the electromagnetic field dosimetry. In addition, the magnetic field associated with grinders, an air hammer, and a drill using electromagnetic anchorage were measured; however, the magnetic fields were much lower than those generated in the welding process. These results agreed well with the results of the electromagnetic field dosimetry (1.49 mT at the wrist position), and the calculated eddy current (4.28 mA/m(2)) was much lower than the well-known guideline thresholds for electrical nerve or muscular stimulation.

  10. Mean field limit for bosons and propagation of Wigner measures

    NASA Astrophysics Data System (ADS)

    Ammari, Z.; Nier, F.

    2009-04-01

    We consider the N-body Schrödinger dynamics of bosons in the mean field limit with a bounded pair-interaction potential. According to the previous work [Ammari, Z. and Nier, F., "Mean field limit for bosons and infinite dimensional phase-space analysis," Ann. Henri Poincare 9, 1503 (2008)], the mean field limit is translated into a semiclassical problem with a small parameter ɛ →0, after introducing an ɛ-dependent bosonic quantization. The limits of quantum correlation functions are expressed as a push forward by a nonlinear flow (e.g., Hartree) of the associated Wigner measures. These object and their basic properties were introduced by Ammari and Nier in the infinite dimensional setting. The additional result presented here states that the transport by the nonlinear flow holds for a rather general class of quantum states in their mean field limit.

  11. Mean field limit for bosons and propagation of Wigner measures

    SciTech Connect

    Ammari, Z.; Nier, F.

    2009-04-15

    We consider the N-body Schroedinger dynamics of bosons in the mean field limit with a bounded pair-interaction potential. According to the previous work [Ammari, Z. and Nier, F., 'Mean field limit for bosons and infinite dimensional phase-space analysis', Ann. Henri Poincare 9, 1503 (2008)], the mean field limit is translated into a semiclassical problem with a small parameter {epsilon}{yields}0, after introducing an {epsilon}-dependent bosonic quantization. The limits of quantum correlation functions are expressed as a push forward by a nonlinear flow (e.g., Hartree) of the associated Wigner measures. These object and their basic properties were introduced by Ammari and Nier in the infinite dimensional setting. The additional result presented here states that the transport by the nonlinear flow holds for a rather general class of quantum states in their mean field limit.

  12. A field method for measurement of infiltration

    USGS Publications Warehouse

    Johnson, A.I.

    1963-01-01

    The determination of infiltration--the downward entry of water into a soil (or sediment)--is receiving increasing attention in hydrologic studies because of the need for more quantitative data on all phases of the hydrologic cycle. A measure of infiltration, the infiltration rate, is usually determined in the field by flooding basins or furrows, sprinkling, or measuring water entry from cylinders (infiltrometer rings). Rates determined by ponding in large areas are considered most reliable, but the high cost usually dictates that infiltrometer rings, preferably 2 feet in diameter or larger, be used. The hydrology of subsurface materials is critical in the study of infiltration. The zone controlling the rate of infiltration is usually the least permeable zone. Many other factors affect infiltration rate--the sediment (soil) structure, the condition of the sediment surface, the distribution of soil moisture or soil- moisture tension, the chemical and physical nature of the sediments, the head of applied water, the depth to ground water, the chemical quality and the turbidity of the applied water, the temperature of the water and the sediments, the percentage of entrapped air in the sediments, the atmospheric pressure, the length of time of application of water, the biological activity in the sediments, and the type of equipment or method used. It is concluded that specific values of the infiltration rate for a particular type of sediment are probably nonexistent and that measured rates are primarily for comparative use. A standard field-test method for determining infiltration rates by means of single- or double-ring infiltrometers is described and the construction, installation, and operation of the infiltrometers are discussed in detail.

  13. Diamond field emitter array cathodes and possibilities of employing additive manufacturing for dielectric laser accelerating structures

    NASA Astrophysics Data System (ADS)

    Simakov, Evgenya I.; Andrews, Heather L.; Herman, Matthew J.; Hubbard, Kevin M.; Weis, Eric

    2017-03-01

    Demonstration of a stand-alone practical dielectric laser accelerator (DLA) requires innovation in two major critical components: high-current ultra-low-emittance cathodes and efficient laser accelerator structures. LANL develops two technologies that in our opinion are applicable to the novel DLA architectures: diamond field emitter array (DFEA) cathodes and additive manufacturing of photonic band-gap (PBG) structures. This paper discusses the results of testing of DFEA cathodes in the field-emission regime and the possibilities for their operation in the photoemission regime, and compares their emission characteristics to the specific needs of DLAs. We also describe recent advances in additive manufacturing of dielectric woodpile structures using a Nanoscribe direct laser-writing device capable of maskless lithography and additive manufacturing, and the development of novel infrared dielectric materials compatible with additive manufacturing.

  14. MESSENGER Measurements of Mercury's Magnetic Field during the First Flyby

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Boardsen, S. A.; Acuna, M. H.; Anderson, B. J.; Johnson, C. L.; Korth, H.; Krimigis, S. M.; McNutt, R. L., Jr.; Purucker, M. E.; Solomon, S. C.

    2008-01-01

    On 14 January 2008 the MESSENGER spacecraft will encounter Mercury for the first time. Depending upon the solar wind conditions, this initial flyby will return Magnetometer measurements of Mercury's magnetic field over a time interval lasting between - 30 md 60 min. Closest approach for MESSENGER is targeted for an altitude of 200 km as compared with the 707 krn and 327 km attained by Mariner 10 on 29 March 1974 and 16 March 1975, respectively. Furthermore, the differences in the MESSENGER and Mariner 10 encounter trajectories, with respect both to magnetospheric and body-fixed coordinates are highly complementary and expected to lead to significant improvements in our knowledge of Mercury's magnetic field. We present an overview of the MESSENGER magnetic field observations, an initial subtraction of the magnetic fields attributable to magnetospheric current systems from the total measured magnetic field, and an improved model of Mercury's intrinsic magnetic field. We also discuss the expected advances afforded by the two additional MESSENGER flybys, which occur in October 2008 and September 2009, as well as the orbital phase that will begin in March 201 1.

  15. Comparing laboratory and field measured bioaccumulation endpoints.

    PubMed

    Burkhard, Lawrence P; Arnot, Jon A; Embry, Michelle R; Farley, Kevin J; Hoke, Robert A; Kitano, Masaru; Leslie, Heather A; Lotufo, Guilherme R; Parkerton, Thomas F; Sappington, Keith G; Tomy, Gregg T; Woodburn, Kent B

    2012-01-01

    An approach for comparing laboratory and field measures of bioaccumulation is presented to facilitate the interpretation of different sources of bioaccumulation data. Differences in numerical scales and units are eliminated by converting the data to dimensionless fugacity (or concentration-normalized) ratios. The approach expresses bioaccumulation metrics in terms of the equilibrium status of the chemical, with respect to a reference phase. When the fugacity ratios of the bioaccumulation metrics are plotted, the degree of variability within and across metrics is easily visualized for a given chemical because their numerical scales are the same for all endpoints. Fugacity ratios greater than 1 indicate an increase in chemical thermodynamic activity in organisms with respect to a reference phase (e.g., biomagnification). Fugacity ratios less than 1 indicate a decrease in chemical thermodynamic activity in organisms with respect to a reference phase (e.g., biodilution). This method provides a holistic, weight-of-evidence approach for assessing the biomagnification potential of individual chemicals because bioconcentration factors, bioaccumulation factors, biota-sediment accumulation factors, biomagnification factors, biota-suspended solids accumulation factors, and trophic magnification factors can be included in the evaluation. The approach is illustrated using a total 2393 measured data points from 171 reports, for 15 nonionic organic chemicals that were selected based on data availability, a range of physicochemical partitioning properties, and biotransformation rates. Laboratory and field fugacity ratios derived from the various bioaccumulation metrics were generally consistent in categorizing substances with respect to either an increased or decreased thermodynamic status in biota, i.e., biomagnification or biodilution, respectively. The proposed comparative bioaccumulation endpoint assessment method could therefore be considered for decision making in a

  16. Field methods for measurement of fluvial sediment

    USGS Publications Warehouse

    Edwards, Thomas K.; Glysson, G. Douglas

    1999-01-01

    This chapter describes equipment and procedures for collection and measurement of fluvial sediment. The complexity of the hydrologic and physical environments and man's ever-increasing data needs make it essential for those responsible for the collection of sediment data to be aware of basic concepts involved in processes of erosion, transport, deposition of sediment, and equipment and procedures necessary to representatively collect sediment data. In addition to an introduction, the chapter has two major sections. The 'Sediment-Sampling Equipment' section encompasses discussions of characteristics and limitations of various models of depth- and point-integrating samplers, single-stage samplers, bed-material samplers, bedload samplers, automatic pumping samplers, and support equipment. The 'Sediment-Sampling Techniques'` section includes discussions of representative sampling criteria, characteristics of sampling sites, equipment selection relative to the sampling conditions and needs, depth and point-integration techniques, surface and dip sampling, determination of transit rates, sampling programs and related data, cold-weather sampling, bed-material and bedload sampling, measuring total sediment discharge, and measuring reservoir sedimentation rates.

  17. Measurement of the magnetic field coefficients of particle accelerator magnets

    SciTech Connect

    Herrera, J.; Ganetis, G.; Hogue, R.; Rogers, E.; Wanderer, P.; Willen, E.

    1989-01-01

    An important aspect in the development of magnets to be used in particle accelerators is the measurement of the magnetic field in the beam aperture. In general it is necessary to measure the harmonic multipoles in the dipole, quadrupole, and sextupole magnets for a series of stationary currents (plateaus). This is the case for the Superconducting Super Collider (SSC) which will be ramped to high field over a long period (/approximately/1000 sec.) and then remain on the flat top for the duration of the particle collision phase. In contrast to this mode of operation, the Booster ring being constructed for the Brookhaven AGS, will have a fast ramp rate of approximately 10 Hz. The multipole fields for these Booster magnets must therefore be determined ''on the ramp.'' In this way the effect of eddy currents will be taken into account. The measurement system which we will describe in this paper is an outgrowth of that used for the SSC dipoles. It has the capability of measuring the field multipoles on both a plateau or during a fast ramp. In addition, the same basic coil assembly is used to obtain the magnetic multipoles in dipole, quadrupole, and sextupole magnets. 2 refs., 3 figs., 1 tab.

  18. Sound field separation with sound pressure and particle velocity measurements.

    PubMed

    Fernandez-Grande, Efren; Jacobsen, Finn; Leclère, Quentin

    2012-12-01

    In conventional near-field acoustic holography (NAH) it is not possible to distinguish between sound from the two sides of the array, thus, it is a requirement that all the sources are confined to only one side and radiate into a free field. When this requirement cannot be fulfilled, sound field separation techniques make it possible to distinguish between outgoing and incoming waves from the two sides, and thus NAH can be applied. In this paper, a separation method based on the measurement of the particle velocity in two layers and another method based on the measurement of the pressure and the velocity in a single layer are proposed. The two methods use an equivalent source formulation with separate transfer matrices for the outgoing and incoming waves, so that the sound from the two sides of the array can be modeled independently. A weighting scheme is proposed to account for the distance between the equivalent sources and measurement surfaces and for the difference in magnitude between pressure and velocity. Experimental and numerical studies have been conducted to examine the methods. The double layer velocity method seems to be more robust to noise and flanking sound than the combined pressure-velocity method, although it requires an additional measurement surface. On the whole, the separation methods can be useful when the disturbance of the incoming field is significant. Otherwise the direct reconstruction is more accurate and straightforward.

  19. Langevin simulation of scalar fields: Additive and multiplicative noises and lattice renormalization

    NASA Astrophysics Data System (ADS)

    Cassol-Seewald, N. C.; Farias, R. L. S.; Fraga, E. S.; Krein, G.; Ramos, Rudnei O.

    2012-08-01

    We consider the Langevin lattice dynamics for a spontaneously broken λϕ4 scalar field theory where both additive and multiplicative noise terms are incorporated. The lattice renormalization for the corresponding stochastic Ginzburg-Landau-Langevin and the subtleties related to the multiplicative noise are investigated.

  20. Additional Enhancement of Electric Field in Surface-Enhanced Raman Scattering due to Fresnel Mechanism

    NASA Astrophysics Data System (ADS)

    Jayawardhana, Sasani; Rosa, Lorenzo; Juodkazis, Saulius; Stoddart, Paul R.

    2013-08-01

    Surface-enhanced Raman scattering (SERS) is attracting increasing interest for chemical sensing, surface science research and as an intriguing challenge in nanoscale plasmonic engineering. Several studies have shown that SERS intensities are increased when metal island film substrates are excited through a transparent base material, rather than directly through air. However, to our knowledge, the origin of this additional enhancement has never been satisfactorily explained. In this paper, finite difference time domain modeling is presented to show that the electric field intensity at the dielectric interface between metal particles is higher for ``far-side'' excitation than ``near-side''. This is reasonably consistent with the observed enhancement for silver islands on SiO2. The modeling results are supported by a simple analytical model based on Fresnel reflection at the interface, which suggests that the additional SERS signal is caused by near-field enhancement of the electric field due to the phase shift at the dielectric interface.

  1. Near-field measurements of the even-order harmonics undetectable in far-field measurements

    NASA Astrophysics Data System (ADS)

    Moiseyev, Nimrod

    2016-12-01

    Even-order harmonics (EOHs) are generated for oriented molecules and for atoms under specific conditions. Here, we focus on the most common situations where EOHs are not observed in far-field measurements. We propose an experiment to show that the EOHs are produced close to the nucleus but are not detected in the far-field measurements due to destructive interferences of the propagated EOHs of the emitted radiation. However, Rydberg gas atoms (e.g., rubidium), which are out of the focus of the laser beam, are expected to be ionized due to their weak interaction with a specific EOH of helium, which is not observed by the far-field detector. The ionization energy of the Rydberg gas atoms should be in resonance with the single-photon energy of a specific EOH.

  2. Laboratory and Field Evaluation of Fluid-Loss Additive Systems Used in the Williston Basin

    SciTech Connect

    Woo, G.T.; Cramer, D.D.

    1984-05-01

    Many formations in the Williston Basin are naturally fractured limestones and dolomites. Naturally fractured reservoirs are typically the most difficult to maintain control of fracturing fluid leakoff. Treatments in the Mission Canyon, Midale and Ratcliffe formations of the Madison Group have had high fracturing fluid leakoffs. Polymer/inert solids mixtures, 100 mesh sand, silica flour and oil-soluble resins have been used in an attempt to control fluid loss. These additives have not consistently solved the problem of excessive fluid loss, and frequent screenouts, gel-outs or pressure-outs have resulted. A laboratory simulation of naturally fractured reservoir leakoff was employed to evaluate the efficiency of ten fluid loss additive systems. Tapered-slot fluid loss tests and proppant pack damage tests were performed using each additive system. Five fluid loss additive systems were identified which performed well in both tests. This paper also summarizes the results of a field evaluation of nine of the original ten fluid loss additive systems used in 70 wells in the Madison Group. Two fluid loss additive systems, a mixture of silica flour and 100 mesh sand, and a mixture of oil-soluble resin (nominal 250 mesh) and 100 mesh sand, performed well in the laboratory tests and had a high success rate in the field.

  3. Matching of additive and polarizable force fields for multiscale condensed phase simulations

    PubMed Central

    Baker, Christopher M.; Best, Robert B.

    2013-01-01

    Inclusion of electronic polarization effects is one of the key aspects in which the accuracy of current biomolecular force fields may be improved. The principal drawback of such approaches is the computational cost, which typically ranges from 3 – 10 times that of the equivalent additive model, and may be greater for more sophisticated treatments of polarization or other many-body effects. Here, we present a multiscale approach which may be used to enhance the sampling in simulations with polarizable models, by using the additive model as a tool to explore configuration space. We use a method based on information theory to determine the charges for an additive model that has optimal overlap with the polarizable one, and we demonstrate the feasibility of enhancing sampling via a hybrid replica exchange scheme for several model systems. An additional advantage is that, in the process, we obtain a systematic method for deriving charges for an additive model that will be the natural complement to its polarizable parent. The additive charges are found by an effective coarse-graining of the polarizable force field, rather than by ad hoc procedures. PMID:23997691

  4. Aircraft electric field measurements: Calibration and ambient field retrieval

    NASA Technical Reports Server (NTRS)

    Koshak, William J.; Bailey, Jeff; Christian, Hugh J.; Mach, Douglas M.

    1994-01-01

    An aircraft locally distorts the ambient thundercloud electric field. In order to determine the field in the absence of the aircraft, an aircraft calibration is required. In this work a matrix inversion method is introduced for calibrating an aircraft equipped with four or more electric field sensors and a high-voltage corona point that is capable of charging the aircraft. An analytic, closed form solution for the estimate of a (3 x 3) aircraft calibration matrix is derived, and an absolute calibration experiment is used to improve the relative magnitudes of the elements of this matrix. To demonstrate the calibration procedure, we analyze actual calibration date derived from a Lear jet 28/29 that was equipped with five shutter-type field mill sensors (each with sensitivities of better than 1 V/m) located on the top, bottom, port, starboard, and aft positions. As a test of the calibration method, we analyze computer-simulated calibration data (derived from known aircraft and ambient fields) and explicitly determine the errors involved in deriving the variety of calibration matrices. We extend our formalism to arrive at an analytic solution for the ambient field, and again carry all errors explicitly.

  5. Decomposition of conifer tree bark under field conditions: effects of nitrogen and phosphorus additions

    NASA Astrophysics Data System (ADS)

    Lopes de Gerenyu, Valentin; Kurganova, Irina; Kapitsa, Ekaterina; Shorokhova, Ekaterina

    2016-04-01

    In forest ecosystems, the processes of decomposition of coarse woody debris (CWD) can contribute significantly to the emission component of carbon (C) cycle and thus accelerate the greenhouse effect and global climate change. A better understanding of decomposition of CWD is required to refine estimates of the C balance in forest ecosystems and improve biogeochemical models. These estimates will in turn contribute to assessing the role of forests in maintaining their long-term productivity and other ecosystems services. We examined the decomposition rate of coniferous bark with added nitrogen (N) and phosphorus (P) fertilizers in experiment under field conditions. The experiment was carried out in 2015 during 17 weeks in Moscow region (54o50'N, 37o36'E) under continental-temperate climatic conditions. The conifer tree bark mixture (ca. 70% of Norway spruce and 30% of Scots pine) was combined with soil and placed in piles of soil-bark substrate (SBS) with height of ca. 60 cm and surface area of ca. 3 m2. The dry mass ratio of bark to soil was 10:1. The experimental design included following treatments: (1) soil (Luvisols Haplic) without bark, (S), (2) pure SBS, (3) SBS with N addition in the amount of 1% of total dry bark mass (SBS-N), and (4) SBS with N and P addition in the amount of 1% of total dry bark mass for each element (SBS-NP). The decomposition rate expressed as CO2 emission flux, g C/m2/h was measured using closed chamber method 1-3 times per week from July to early November using LiCor 6400 (Nebraska, USA). During the experiment, we also controlled soil temperature at depths of 5, 20, 40, and 60 cm below surface of SBS using thermochrons iButton (DS1921G, USA). The pattern of CO2 emission rate from SBS depended strongly on fertilizing. The highest decomposition rates (DecR) of 2.8-5.6 g C/m2/h were observed in SBS-NP treatment during the first 6 weeks of experiment. The decay process of bark was less active in the treatment with only N addition. In this

  6. Field methods for measuring concentrated flow erosion

    NASA Astrophysics Data System (ADS)

    Castillo, C.; Pérez, R.; James, M. R.; Quinton, J. N.; Taguas, E. V.; Gómez, J. A.

    2012-04-01

    Many studies have stressed the importance of gully erosion in the overall soil loss and sediment yield of agricultural catchments, for instance in recent years (Vandaele and Poesen, 1995; De Santisteban et al., 2006; Wu el al, 2008). Several techniques have been used for determining gully erosion in field studies. The conventional techniques involved the use of different devices (i.e. ruler, pole, tape, micro-topographic profilers, total station) to calculate rill and gully volumes through the determination of cross sectional areas and length of reaches (Casalí et al, 1999; Hessel and van Asch, 2003). Optical devices (i.e. laser profilemeters) have also been designed for the purpose of rapid and detailed assessment of cross sectional areas in gully networks (Giménez et al., 2009). These conventional 2d methods provide a simple and un-expensive approach for erosion evaluation, but are time consuming to carry out if a good accuracy is required. On the other hand, remote sensing techniques are being increasingly applied to gully erosion investigation such as aerial photography used for big-scale, long-term, investigations (e.g. Martínez-Casasnovas et al., 2004; Ionita, 2006), airborne and terrestrial LiDAR datasets for gully volume evaluation (James et al., 2007; Evans and Lindsay, 2010) and recently, major advances in 3D photo-reconstruction techniques (Welty et al. 2010, James et al., 2011). Despite its interest, few studies simultaneously compare the accuracies of the range of conventional and remote sensing techniques used, or define the most suitable method for a particular scale, given and time and cost constraints. That was the reason behind the International Workshop Innovations in the evaluation and measurement of rill and gully erosion, held in Cordoba in May 2011 and from which derive part of the materials presented in this abstract. The main aim of this work was to compare the accuracy and time requirements of traditional (2D) and recently developed

  7. Prospects for cost reductions from relaxing additional cross-border measures related to livestock trade.

    PubMed

    Hop, G E; Mourits, M C M; Slager, R; Oude Lansink, A G J M; Saatkamp, H W

    2013-05-01

    Compared with the domestic trade in livestock, intra-communal trade across the European Union (EU) is subject to costly, additional veterinary measures. Short-distance transportation just across a border requires more measures than long-distance domestic transportation, while the need for such additional cross-border measures can be questioned. This study examined the prospects for cost reductions from relaxing additional cross-border measures related to trade within the cross-border region of the Netherlands (NL) and Germany (GER); that is, North Rhine Westphalia and Lower Saxony. The study constructed a deterministic spread-sheet cost model to calculate the costs of both routine veterinary measures (standard measures that apply to both domestic and cross-border transport) and additional cross-border measures (extra measures that only apply to cross-border transport) as applied in 2010. This model determined costs by stakeholder, region and livestock sector, and studied the prospects for cost reduction by calculating the costs after the relaxation of additional cross-border measures. The selection criteria for relaxing these measures were (1) a low expected added value on preventing contagious livestock diseases, (2) no expected additional veterinary risks in case of relaxation of measures and (3) reasonable cost-saving possibilities. The total cost of routine veterinary measures and additional cross-border measures for the cross-border region was €22.1 million, 58% (€12.7 million) of which came from additional cross-border measures. Two-thirds of this €12.7 million resulted from the trade in slaughter animals. The main cost items were veterinary checks on animals (twice in the case of slaughter animals), export certification and control of export documentation. Four additional cross-border measures met the selection criteria for relaxation. The relaxation of these measures could save €8.2 million (€5.0 million for NL and €3.2 million for GER) annually

  8. Field Testing of a Wet FGD Additive for Enhanced Mercury Control - Pilot-Scale Test Results

    SciTech Connect

    Gary M. Blythe

    2006-03-01

    This Topical Report summarizes progress on Cooperative Agreement DE-FC26-04NT42309, ''Field Testing of a Wet FGD Additive.'' The objective of the project is to demonstrate the use of a flue gas desulfurization (FGD) additive, Degussa Corporation's TMT-15, to prevent the reemissions of elemental mercury (Hg{sup 0}) in flue gas exiting wet FGD systems on coal-fired boilers. Furthermore, the project intends to demonstrate that the additive can be used to precipitate most of the mercury (Hg) removed in the wet FGD system as a fine TMT salt that can be separated from the FGD liquor and bulk solid byproducts for separate disposal. The project will conduct pilot and full-scale tests of the TMT-15 additive in wet FGD absorbers. The tests are intended to determine required additive dosage requirements to prevent Hg{sup 0} reemissions and to separate mercury from the normal FGD byproducts for three coal types: Texas lignite/Power River Basin (PRB) coal blend, high-sulfur Eastern bituminous coal, and low-sulfur Eastern bituminous coal. The project team consists of URS Group, Inc., EPRI, TXU Generation Company LP, Southern Company, and Degussa Corporation. TXU Generation has provided the Texas lignite/PRB co-fired test site for pilot FGD tests, Monticello Steam Electric Station Unit 3. Southern Company is providing the low-sulfur Eastern bituminous coal host site for wet scrubbing tests, as well as the pilot and full-scale jet bubbling reactor (JBR) FGD systems to be tested. A third utility, to be named later, will provide the high-sulfur Eastern bituminous coal full-scale FGD test site. Degussa Corporation is providing the TMT-15 additive and technical support to the test program. The project is being conducted in six tasks. Of the six project tasks, Task 1 involves project planning and Task 6 involves management and reporting. The other four tasks involve field testing on FGD systems, either at pilot or full scale. The four tasks include: Task 2 - Pilot Additive Testing in

  9. Measuring the absolute magnetic field using high-Tc SQUID

    NASA Astrophysics Data System (ADS)

    He, D. F.; Itozaki, H.

    2006-06-01

    SQUID normally can only measure the change of magnetic field instead of the absolute value of magnetic field. Using a compensation method, a mobile SQUID, which could keep locked when moving in the earth's magnetic field, was developed. Using the mobile SQUID, it was possible to measure the absolute magnetic field. The absolute value of magnetic field could be calculated from the change of the compensation output when changing the direction of the SQUID in a magnetic field. Using this method and the mobile SQUID, we successfully measured the earth's magnetic field in our laboratory.

  10. Field Assessment of Acoustic-Doppler Based Discharge Measurements

    USGS Publications Warehouse

    Mueller, D.S.; ,

    2002-01-01

    The use of equipment based on the Doppler principle for measuring water velocity and computing discharge is common within the U.S. Geological Survey (USGS). The instruments and software have changed appreciably during the last 5 years; therefore, the USGS has begun a field validation of the instruments currently (2002) available for making discharge measurements from a moving boat in streams of various sizes. Instruments manufactured by SonTek/YSI2 and RD Instruments, Inc. were used to collect discharge data at five different sites. One or more traditional discharge measurements were made by the use of a Price AA current meter and standard USGS procedures with the acoustic instruments at each site during data collection. The discharges measured with the acoustic instruments were compared with the discharges measured with Price AA meters and the current USGS stage-discharge rating for each site. The mean discharges measured by each acoustic instrument were within 5 percent of the Price AA-based measurement and (or) discharge from the stage-discharge rating. Additional analysis of the data collected indicates that the coefficient of variation of the discharge measurements consistently was less for the RD Instruments, Inc. Rio Grandes than it was for the SonTek/YSI RiverSurveyors. The bottom-tracking referenced measurement had a lower coefficient of variation than the differentially corrected global positioning system referenced measurements. It was observed that the higher frequency RiverSurveyors measured a moving bed more often than the lower frequency Rio Grandes. The detection of a moving bed caused RiverSurveyors to be consistently biased low when referenced to bottom tracking. Differentially corrected global positioning system data may be used to remove the bias observed in the bottom-tracking referenced measurements.

  11. DEVELOPMENT OF A PRECISE MAGNETIC FIELD MEASUREMENT SYSTEM FOR FAST-CHANGING MAGNETIC FIELDS.

    SciTech Connect

    WANDERER,P.; ESCALLIER,J.; GANETIS,G.; JAIN,A.; LOUIE,W.; MARONE,A.; THOMAS,R.

    2003-06-15

    Several recent applications for fast ramped magnets have been found that require precise measurement of the time-dependent fields. In one instance, accelerator dipoles will be ramped at 1 T/sec, with measurements needed to the typical level of accuracy for accelerators, {Delta} B/B better than 0.01%. To meet this need, we have begun development of a system containing 16 stationary pickup windings that will be sampled at a high rate. It is hoped that harmonics through the decapole can be measured with this system. Precise measurement of the time-dependent harmonics requires that both the pickup windings and the voltmeters be nearly identical. To minimize costs, printed circuit boards are being used for the pickup windings and a combination of amplifiers and ADC's for voltmeters. In addition, new software must be developed for the analysis. The paper will present a status report on this work.

  12. Additional Enhancement of Electric Field in Surface-Enhanced Raman Scattering due to Fresnel Mechanism

    PubMed Central

    Jayawardhana, Sasani; Rosa, Lorenzo; Juodkazis, Saulius; Stoddart, Paul R.

    2013-01-01

    Surface-enhanced Raman scattering (SERS) is attracting increasing interest for chemical sensing, surface science research and as an intriguing challenge in nanoscale plasmonic engineering. Several studies have shown that SERS intensities are increased when metal island film substrates are excited through a transparent base material, rather than directly through air. However, to our knowledge, the origin of this additional enhancement has never been satisfactorily explained. In this paper, finite difference time domain modeling is presented to show that the electric field intensity at the dielectric interface between metal particles is higher for “far-side” excitation than “near-side”. This is reasonably consistent with the observed enhancement for silver islands on SiO2. The modeling results are supported by a simple analytical model based on Fresnel reflection at the interface, which suggests that the additional SERS signal is caused by near-field enhancement of the electric field due to the phase shift at the dielectric interface. PMID:23903714

  13. Field evaluation of some bait additives against Indian crested porcupine (Hystrix indica) (Rodentia: Hystricidae).

    PubMed

    Mushtaq, Muhammad; Hussain, Iftikhar; Mian, Afsar; Munir, Shahid; Ahmed, Irfan; Khan, Abdul Aziz

    2013-09-01

    This research study evaluated the effect of different additives on the bait consumption by Indian crested porcupine, a serious forest and agricultural pest, under field conditions. Different additives (saccharin, common salt, bone meal, fish meal, peanut butter, egg yolk, egg shell powder, yeast powder, mineral oil and coconut oil) at 2 and 5% each were tested for their relative preference, using groundnut-maize (1:1) as basic bait. All the additives were tested under a no-choice test pattern. For control tests, no additive was mixed with the basic bait. Saccharin at 5% concentration significantly enhanced the consumption of bait over the basic bait, while 2% saccharin supplemented bait resulted in a non-significant bait consumption. All other additives did not enhance the consumption of the bait material; rather, these worked as repellents. However, the repellency was lowest with the common salt, followed by egg yolk, egg shell powder, bone meal, peanut butter, mineral oil, fish meal and yeast powder, while coconut remained the most repellent compound. The present study suggested that groundnut-maize (1:1) supplemented with 5% saccharin was the preferred bait combination, and can be used with different rodenticides for the management of Indian crested porcupine.

  14. Field Testing of a Wet FGD Additive for Enhanced Mercury Control

    SciTech Connect

    Gary Blythe; MariJon Owens

    2007-12-31

    This document is the final report for DOE-NETL Cooperative Agreement DE-FC26-04NT42309, 'Field Testing of a Wet FGD Additive'. The objective of the project has been to demonstrate the use of two flue gas desulfurization (FGD) additives, Evonik Degussa Corporation's TMT-15 and Nalco Company's Nalco 8034, to prevent the re-emission of elemental mercury (Hg{sup 0}) in flue gas exiting wet FGD systems on coal-fired boilers. Furthermore, the project was intended to demonstrate whether such additives can be used to precipitate most of the mercury (Hg) removed in the wet FGD system as a fine salt that can be separated from the FGD liquor and bulk solid byproducts for separate disposal. The project involved pilot- and full-scale tests of the additives in wet FGD absorbers. The tests were intended to determine required additive dosages to prevent Hg{sup 0} re-emissions and to separate mercury from the normal FGD byproducts for three coal types: Texas lignite/Powder River Basin (PRB) coal blend, high-sulfur Eastern bituminous coal, and low-sulfur Eastern bituminous coal. The project team consists of URS Group, Inc., EPRI, Luminant Power (was TXU Generation Company LP), Southern Company, IPL (an AES company), Evonik Degussa Corporation and the Nalco Company. Luminant Power provided the Texas lignite/PRB co-fired test site for pilot FGD tests and project cost sharing. Southern Company provided the low-sulfur Eastern bituminous coal host site for wet scrubbing tests, the pilot- and full-scale jet bubbling reactor (JBR) FGD systems tested, and project cost sharing. IPL provided the high-sulfur Eastern bituminous coal full-scale FGD test site and cost sharing. Evonik Degussa Corporation provided the TMT-15 additive, and the Nalco Company provided the Nalco 8034 additive. Both companies also supplied technical support to the test program as in-kind cost sharing. The project was conducted in six tasks. Of the six tasks, Task 1 involved project planning and Task 6 involved

  15. Optomap ultrawide field imaging identifies additional retinal abnormalities in patients with diabetic retinopathy

    PubMed Central

    Price, Liam D; Au, Stephanie; Chong, N Victor

    2015-01-01

    Purpose To compare diabetic retinopathy (DR) severity grading between Optomap ultrawide field scanning laser ophthalmoscope (UWFSLO) 200° images and an Early Treatment Diabetic Retinopathy Study (ETDRS) seven-standard field view. Methods Optomap UWFSLO images (total: 266) were retrospectively selected for evidence of DR from a database of eye clinic attendees. The Optomap UWFSLO images were graded for DR severity by two masked assessors. An ETDRS seven-field mask was overlaid on the Optomap UWFSLO images, and the DR grade was assessed for the region inside the mask. Any interassessor discrepancies were adjudicated by a senior retinal specialist. Kappa agreement levels were used for statistical analysis. Results Fifty images (19%) (P<0.001) were assigned a higher DR level in the Optomap UWFSLO view compared to the ETDRS seven-field view, which resulted in 40 images (15%) (P<0.001) receiving a higher DR severity grade. DR severity grades in the ETDRS seven-field view compared with the Optomap UWFSLO view were identical in 85% (226) of the images and within one severity level in 100% (266) of the images. Agreement between the two views was substantial: unweighted κ was 0.74±0.04 (95% confidence interval: 0.67–0.81) and weighted κ was 0.80±0.03 (95% confidence interval: 0.74–0.86). Conclusion Compared to the ETDRS seven-field view, a significant minority of patients are diagnosed with more severe DR when using the Optomap UWFSLO view. The clinical significance of additional peripheral lesions requires evaluation in future prospective studies using large cohorts. PMID:25848202

  16. The force-field derivation and application of explosive/additive interfaces

    NASA Astrophysics Data System (ADS)

    Long, Yao; Chen, Jun

    2016-10-01

    The inter-molecular force-field across RDX/(paraffin, fluoropolymer) interfaces are derived from first-principles calculated energies under the GGA+vdW functional. Based on the force-field, the polycrystal structures of mixture explosives are obtained, and a set of thermodynamic properties are calculated, including the elastic constants, thermal expansion coefficient, heat capacity, isothermal curve and the Hugoniot curve. The results are in good agreement with the available experiments, and provide a reasonable prediction about the properties of plastic bonded explosives. We find that the thermal expansion coefficient of a multi-component explosive is not only determined by the properties of the components, but is also affected by the thermal stress at the explosive/additive interfaces.

  17. Phase-Field Modeling of Microstructure Evolution in Electron Beam Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Gong, Xibing; Chou, Kevin

    2015-05-01

    In this study, the microstructure evolution in the powder-bed electron beam additive manufacturing (EBAM) process is studied using phase-field modeling. In essence, EBAM involves a rapid solidification process and the properties of a build partly depend on the solidification behavior as well as the microstructure of the build material. Thus, the prediction of microstructure evolution in EBAM is of importance for its process optimization. Phase-field modeling was applied to study the microstructure evolution and solute concentration of the Ti-6Al-4V alloy in the EBAM process. The effect of undercooling was investigated through the simulations; the greater the undercooling, the faster the dendrite grows. The microstructure simulations show multiple columnar-grain growths, comparable with experimental results for the tested range.

  18. Photon-assisted field emission from a Si tip at addition of an AC low voltage

    NASA Astrophysics Data System (ADS)

    Zaporozhchenko, A. V.; Chernov, S. V.; Odnodvorets, L. V.; Stetsenko, B. V.; Nepijko, S. A.; Elmers, H. J.; Schönhense, G.

    2015-07-01

    We investigated the field emission current from a p-type silicon tip with large resistivity of 4 × 103 Ω cm for light illumination with a photon energy of 1.3 eV and tip-anode voltages of 0.7-5.0 kV. Additional AC voltage with amplitude 30-60 V and frequency varying in the range of 10-107 Hz was applied to the tip which resulted in variations of emission current. We investigated the dependence of this phenomenon on the AC signal parameters, light intensity and temperature. The resonant-like frequency dependence of the emission current is because the tip acts as a driven plasmonic resonator. The results represent an important step forward for the development of high-frequency display systems based on electron field emission.

  19. Diamond field emitter array cathodes and possibilities for employing additive manufacturing for dielectric laser accelerating structures

    SciTech Connect

    Simakov, Evgenya Ivanovna; Andrews, Heather Lynn; Herman, Matthew Joseph; Hubbard, Kevin Mark; Weis, Eric

    2016-09-20

    These are slides for a presentation at Stanford University. The outline is as follows: Motivation: customers for compact accelerators, LANL's technologies for laser acceleration, DFEA cathodes, and additive manufacturing of micron-size structures. Among the stated conclusions are the following: preliminary study identified DFEA cathodes as promising sources for DLAs--high beam current and small emittance; additive manufacturing with Nanoscribe Professional GT can produce structures with the right scale features for a DLA operating at micron wavelengths (fabrication tolerances need to be studied, DLAs require new materials). Future plans include DLA experiment with a beam produced by the DFEA cathode with field emission, demonstration of photoemission from DFEAs, and new structures to print and test.

  20. Measuring BSW Student Learning in Field Instruction.

    ERIC Educational Resources Information Center

    Cavazos, Alonzo

    1996-01-01

    A study compared performance on the Area Concentration Achievement Test in Social Work (ACAT) of 32 undergraduates who had nearly completed a field practicum and 38 who had not begun it. Results showed no difference in the groups' knowledge of social work professional foundation overall or in individual content areas. Other variables that could…

  1. Deducing dust emission mechanisms from field measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field observations are needed to both develop and test theories on dust emission for use in global modeling systems. The mechanism of dust emission (aerodynamic entrainment, saltation bombardment, aggregate disintegration) and the amount and particle-size distribution of emitted dust may vary under ...

  2. 49 CFR 192.935 - What additional preventive and mitigative measures must an operator take?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false What additional preventive and mitigative measures... STANDARDS Gas Transmission Pipeline Integrity Management § 192.935 What additional preventive and mitigative... those already required by Part 192 to prevent a pipeline failure and to mitigate the consequences of...

  3. Earth's Magnetic Field Measurements for the LCLS Undulators

    SciTech Connect

    Hacker, Kirsten

    2010-12-13

    Measurements of the earth's magnetic field at several locations at SLAC were conducted to determine the possible field error contribution from tuning the undulators in a location with a different magnetic field than that which will be found in the undulator hall. An average difference of 0.08 {+-} 0.04 Gauss has been measured between the downward earth's field components in the test facility and SLAC tunnel locations.

  4. Field Measurement of the Acoustic Nonlinearity Parameter in Turbine Blades

    NASA Technical Reports Server (NTRS)

    Hinton, Yolanda L.; Na, Jeong K.; Yost, William T.; Kessel, Gregory L.

    2000-01-01

    Nonlinear acoustics techniques were used to measure fatigue in turbine blades in a power generation plant. The measurements were made in the field using a reference based measurement technique, and a reference sample previously measured in the laboratory. The acoustic nonlinearity parameter showed significant increase with fatigue in the blades, as indicated by service age and areas of increased stress. The technique shows promise for effectively measuring fatigue in field applications and predicting subsequent failures.

  5. Interactive responses of grass litter decomposition to warming, nitrogen addition and detritivore access in a temperate old field.

    PubMed

    Moise, Eric R D; Henry, Hugh A L

    2014-12-01

    Plant litter decomposition has been studied extensively in the context of both climate warming and increased atmospheric N deposition. However, much of this research is based on microbial responses, despite the potential for detritivores to contribute substantially to litter breakdown. We measured litter mass-loss responses to the combined effects of warming, N addition and detritivore access in a grass-dominated old field. We concurrently assessed the roles of litter treatment origin vs. microenvironment (direct warming and N-addition effects) to elucidate the mechanisms through which these factors affect decomposition. After 6 weeks, mass loss increased in N-addition plots, and it increased with detritivore access in the absence of warming. After 1 year, warming, N addition, and detritivore access all increased litter mass loss, although the effects of N addition and warming were non-additive in the detritivore-access plots. For the litter-origin experiment, mass loss after 6 weeks increased in litter from N-addition plots and warmed plots, but unlike the overall decomposition response, the N-addition effect was enhanced by detritivore access. Conversely, for the microenvironment experiment, detritivore access only increased mass loss in unfertilized plots. After 1 year, detritivore access increased mass loss in the litter-origin and microenvironment experiments, but there were no warming or N-addition effects. Overall, our results provide support for a substantial role of detritivores in promoting litter mass loss in our system. Moreover, they reveal important interactions between litter origin, microclimate and detritivores in determining decomposition responses to global change.

  6. Cyp26 Enzymes Facilitate Second Heart Field Progenitor Addition and Maintenance of Ventricular Integrity

    PubMed Central

    Rydeen, Ariel B.; Waxman, Joshua S.

    2016-01-01

    Although retinoic acid (RA) teratogenicity has been investigated for decades, the mechanisms underlying RA-induced outflow tract (OFT) malformations are not understood. Here, we show zebrafish embryos deficient for Cyp26a1 and Cyp26c1 enzymes, which promote RA degradation, have OFT defects resulting from two mechanisms: first, a failure of second heart field (SHF) progenitors to join the OFT, instead contributing to the pharyngeal arch arteries (PAAs), and second, a loss of first heart field (FHF) ventricular cardiomyocytes due to disrupted cell polarity and extrusion from the heart tube. Molecularly, excess RA signaling negatively regulates fibroblast growth factor 8a (fgf8a) expression and positively regulates matrix metalloproteinase 9 (mmp9) expression. Although restoring Fibroblast growth factor (FGF) signaling can partially rescue SHF addition in Cyp26 deficient embryos, attenuating matrix metalloproteinase (MMP) function can rescue both ventricular SHF addition and FHF integrity. These novel findings indicate a primary effect of RA-induced OFT defects is disruption of the extracellular environment, which compromises both SHF recruitment and FHF ventricular integrity. PMID:27893754

  7. Cyp26 Enzymes Facilitate Second Heart Field Progenitor Addition and Maintenance of Ventricular Integrity.

    PubMed

    Rydeen, Ariel B; Waxman, Joshua S

    2016-11-01

    Although retinoic acid (RA) teratogenicity has been investigated for decades, the mechanisms underlying RA-induced outflow tract (OFT) malformations are not understood. Here, we show zebrafish embryos deficient for Cyp26a1 and Cyp26c1 enzymes, which promote RA degradation, have OFT defects resulting from two mechanisms: first, a failure of second heart field (SHF) progenitors to join the OFT, instead contributing to the pharyngeal arch arteries (PAAs), and second, a loss of first heart field (FHF) ventricular cardiomyocytes due to disrupted cell polarity and extrusion from the heart tube. Molecularly, excess RA signaling negatively regulates fibroblast growth factor 8a (fgf8a) expression and positively regulates matrix metalloproteinase 9 (mmp9) expression. Although restoring Fibroblast growth factor (FGF) signaling can partially rescue SHF addition in Cyp26 deficient embryos, attenuating matrix metalloproteinase (MMP) function can rescue both ventricular SHF addition and FHF integrity. These novel findings indicate a primary effect of RA-induced OFT defects is disruption of the extracellular environment, which compromises both SHF recruitment and FHF ventricular integrity.

  8. Nitrate removal in stream ecosystems measured by 15N addition experiments: 2. Denitrification

    SciTech Connect

    Mulholland, Patrick J; Hall, Robert; Sobota, Daniel; Dodds, Walter; Findlay, Stuart; Grimm, Nancy; Hamilton, Stephen; McDowell, William; O'Brien, Jon; Tank, Jennifer; Ashkenas, Linda; Cooper, Lee W; Dahm, Cliff; Gregory, Stanley; Johnson, Sherri; Meyer, Judy; Peterson, Bruce; Poole, Geoff; Valett, H. Maurice; Webster, Jackson; Arango, Clay; Beaulieu, Jake; Bernot, Melody; Burgin, Amy; Crenshaw, Chelsea; Helton, Ashley; Johnson, Laura; Niederlehner, Bobbie; Potter, Jody; Sheibley, Rich; Thomas, Suzanne

    2009-01-01

    We measured denitrification rates using a field {sup 15}N-NO{sub 3}{sup -} tracer-addition approach in a large, cross-site study of nitrate uptake in reference, agricultural, and suburban-urban streams. We measured denitrification rates in 49 of 72 streams studied. Uptake length due to denitrification (S{sub Wden}) ranged from 89 m to 184 km (median of 9050 m) and there were no significant differences among regions or land-use categories, likely because of the wide range of conditions within each region and land use. N{sub 2} production rates far exceeded N{sub 2}O production rates in all streams. The fraction of total NO{sub 3}{sup -} removal from water due to denitrification ranged from 0.5% to 100% among streams (median of 16%), and was related to NH{sub 4}{sup +} concentration and ecosystem respiration rate (ER). Multivariate approaches showed that the most important factors controlling S{sub Wden} were specific discharge (discharge/width) and NO{sub 3}{sup -} concentration (positive effects), and ER and transient storage zones (negative effects). The relationship between areal denitrification rate (U{sub den}) and NO{sub 3}{sup -} concentration indicated a partial saturation effect. A power function with an exponent of 0.5 described this relationship better than a Michaelis-Menten equation. Although U{sub den} increased with increasing NO{sub 3}{sup -} concentration, the efficiency of NO{sub 3}{sup -} removal from water via denitrification declined, resulting in a smaller proportion of streamwater NO{sub 3}{sup -} load removed over a given length of stream. Regional differences in stream denitrification rates were small relative to the proximate factors of NO{sub 3}{sup -} concentration and ecosystem respiration rate, and land use was an important but indirect control on denitrification in streams, primarily via its effect on NO{sub 3}{sup -} concentration.

  9. Nitrate removal in stream ecosystems measured by 15N addition experiments: Denitrification

    USGS Publications Warehouse

    Mulholland, P.J.; Hall, R.O.; Sobota, D.J.; Dodds, W.K.; Findlay, S.E.G.; Grimm, N. B.; Hamilton, S.K.; McDowell, W.H.; O'Brien, J. M.; Tank, J.L.; Ashkenas, L.R.; Cooper, L.W.; Dahm, Clifford N.; Gregory, S.V.; Johnson, S.L.; Meyer, J.L.; Peterson, B.J.; Poole, G.C.; Valett, H.M.; Webster, J.R.; Arango, C.P.; Beaulieu, J.J.; Bernot, M.J.; Burgin, A.J.; Crenshaw, C.L.; Helton, A.M.; Johnson, L.T.; Niederlehner, B.R.; Potter, J.D.; Sheibley, R.W.; Thomasn, S.M.

    2009-01-01

    We measured denitrification rates using a field 15N-NO- 3 tracer-addition approach in a large, cross-site study of nitrate uptake in reference, agricultural, and suburban-urban streams. We measured denitrification rates in 49 of 72 streams studied. Uptake length due to denitrification (SWden) ranged from 89 m to 184 km (median of 9050 m) and there were no significant differences among regions or land-use categories, likely because of the wide range of conditions within each region and land use. N2 production rates far exceeded N2O production rates in all streams. The fraction of total NO-3 removal from water due to denitrification ranged from 0.5% to 100% among streams (median of 16%), and was related to NHz 4 concentration and ecosystem respiration rate (ER). Multivariate approaches showed that the most important factors controlling SWden were specific discharge (discharge / width) and NO-3 concentration (positive effects), and ER and transient storage zones (negative effects). The relationship between areal denitrification rate (Uden) and NO- 3 concentration indicated a partial saturation effect. A power function with an exponent of 0.5 described this relationship better than a Michaelis-Menten equation. Although Uden increased with increasing NO- 3 concentration, the efficiency of NO-3 removal from water via denitrification declined, resulting in a smaller proportion of streamwater NO-3 load removed over a given length of stream. Regional differences in stream denitrification rates were small relative to the proximate factors of NO-3 concentration and ecosystem respiration rate, and land use was an important but indirect control on denitrification in streams, primarily via its effect on NO-3 concentration. ?? 2009.

  10. Far-field patterns of spaceborne antennas from plane-polar near-field measurements

    NASA Technical Reports Server (NTRS)

    Rahmat-Samii, Y.; Gatti, M. S.

    1985-01-01

    Certain unique features of a recently constructed plane-polar near-field measurement facility for determining the far-field patterns of large and fragile spaceborne antennas are described. In this facility, the horizontally positioned antenna rotates about its axis while the measuring probe is advanced incrementally in a fixed radial direction. The near-field measured data is then processed using a Jacobi-Bessel expansion to obtain the antenna far fields. A summary of the measurement and computational steps is given. Comparisons between the outdoor far-field measurements and the constructed far-field patterns from the near-field measured data are provided for different antenna sizes and frequencies. Application of the substitution method for the absolute gain measurement is discussed. In particular, results are shown for the 4.8-m mesh-deployable high-gain antenna of the Galileo spacecraft which has the mission of orbiting Jupiter in 1988.

  11. Gradio - Earth gravity field measurement on Aristoteles

    NASA Astrophysics Data System (ADS)

    Pawlak, D.; Meyer, Ph.; Bernard, A.; Touboul, P.

    1991-10-01

    The design and operation of Gradio, the instrument that was specifically designed for precise gradiometry measurements during the Aristoteles mission, are described. The Gradio is based on simultaneous measurements by four three-axis ultrasensitive accelerometers performed in several locations on a rigid stable structure, called gradio plate, which are then used to compute g gradients. The operational phase of Gradio will last 6 months; the orbit will be circular, near polar, and heliosynchronous, at an altitude of 200 km. It is estimated that Gradio will measure the two main components T(yy) and T(zz) of the gravity gradient tensor in the (0.005, 0.125) Hz frequency bandwidth with an accuracy of 0.01 E.U.

  12. The influence of polyvinylacetate additive in water on turbulent velocity field and drag reduction

    NASA Astrophysics Data System (ADS)

    Lodes, A.; Macho, V.

    1989-06-01

    The effect of polymer concentration on drag reduction was studied experimentally with diluted water solutions of polyvinylacetate in a 2.4 cm I. D. pipe. The instantaneous local velocities of the velocity fields were measured by a one-channel differential laser-Doppler anemometer DISA Mark II, with forward scattering. Concentrations of water-polyvinylacetate over the range from 10 to 2,000 ppm were used. The drag reduction coefficient is proportional to the concentration and hydrolysis degree of the saponificated polyvinylacetate (PVAC) employed. A mechanical degradation in the turbulent shear flow was not observed.

  13. Whole-field geophysical measurements using coherent optics

    SciTech Connect

    Conley, E.

    1997-10-01

    This paper describes powerful methods of optics and mechanics brought to bear on important geomechanical problems. Whole-field surface glacier ice flow and mine-wall strains were mapped in two separate feasibility studies using high-resolution photography and coherent light to interrogate the images. Young`s fringe patterns result when a double-exposed transparency of a deforming surface is illuminated by a narrow beam of coherent light. Geometry gives a relationship between the surface displacement vector and the interference fringe patterns. The displacement occurring during the time-lapse interval is thus known. When applied to the surface of the Nisqually Glacier, Mt Rainier National Park, WA, the speckle method yielded ice flow data that was compared with similar flow data acquired by surveying techniques. In the areas for which results can be compared, our experiments yield a flow of .6 meters/day where conventional methods yield about .4 meters/day. The same photographic technique was applied to measure the visco-plastic deformation of a proposed nuclear waste repository carved into bedded salt deep in the earth`s crust Data reduction concluded with the differentiation of the displacement vector map to obtain the two-dimensional strain rate field which correlated well with extensometer-gathered data. The research demonstrates the feasibility of using whole-field optical techniques to map ice flow and mine-wall strains, and confirms certain, but not all, measurements of point-by-point instruments. Field work, data analysis, and additional potential applications of the speckle photography method are indicated.

  14. Behavioral and Locomotor Measurements Using an Open Field Activity Monitoring System for Skeletal Muscle Diseases

    PubMed Central

    Tatem, Kathleen S.; Quinn, James L.; Phadke, Aditi; Yu, Qing; Gordish-Dressman, Heather; Nagaraju, Kanneboyina

    2014-01-01

    The open field activity monitoring system comprehensively assesses locomotor and behavioral activity levels of mice. It is a useful tool for assessing locomotive impairment in animal models of neuromuscular disease and efficacy of therapeutic drugs that may improve locomotion and/or muscle function. The open field activity measurement provides a different measure than muscle strength, which is commonly assessed by grip strength measurements. It can also show how drugs may affect other body systems as well when used with additional outcome measures. In addition, measures such as total distance traveled mirror the 6 min walk test, a clinical trial outcome measure. However, open field activity monitoring is also associated with significant challenges: Open field activity measurements vary according to animal strain, age, sex, and circadian rhythm. In addition, room temperature, humidity, lighting, noise, and even odor can affect assessment outcomes. Overall, this manuscript provides a well-tested and standardized open field activity SOP for preclinical trials in animal models of neuromuscular diseases. We provide a discussion of important considerations, typical results, data analysis, and detail the strengths and weaknesses of open field testing. In addition, we provide recommendations for optimal study design when using open field activity in a preclinical trial. PMID:25286313

  15. A new probe for measuring small electric fields in plasmas

    NASA Technical Reports Server (NTRS)

    Stenzel, R. L.

    1991-01-01

    A dipolar double probe has been developed for in situ measurements of small electric fields in laboratory plasmas. The probe measures dc to ac electric fields (f values between 0 and 20 MHz) with high sensitivity (Emin about 10 microV/cm) and responds to both space charge electric fields and inductive electric fields. Using voltage-to-frequency conversion, the probe signal is obtained free of errors and loading effects by a transmission line. Various examples of useful applications for the new probe are presented, such as measurements of dc ambipolar fields, ac space-charge fields of ion acoustic waves, ac inductive fields of whistler waves, and mixed inductive and space-charge electric fields in current-carrying magnetoplasmas.

  16. Sixport technique for phase measurement of guided optical fields

    NASA Astrophysics Data System (ADS)

    Molina-Fernandez, I.; Ortega-Moñux, A.; Halir, R.; Wangüemert-Pérez, J. G.; Perez-Lara, P.

    2010-04-01

    This paper introduces the sixport technique for precise amplitude and phase measurement of guided optical fields. The main theoretical advances in this topic are reviewed and recent experimental measurements of a Silicon on Insulator sixport PLC reflectometer are presented.

  17. Analysis of error-prone survival data under additive hazards models: measurement error effects and adjustments.

    PubMed

    Yan, Ying; Yi, Grace Y

    2016-07-01

    Covariate measurement error occurs commonly in survival analysis. Under the proportional hazards model, measurement error effects have been well studied, and various inference methods have been developed to correct for error effects under such a model. In contrast, error-contaminated survival data under the additive hazards model have received relatively less attention. In this paper, we investigate this problem by exploring measurement error effects on parameter estimation and the change of the hazard function. New insights of measurement error effects are revealed, as opposed to well-documented results for the Cox proportional hazards model. We propose a class of bias correction estimators that embraces certain existing estimators as special cases. In addition, we exploit the regression calibration method to reduce measurement error effects. Theoretical results for the developed methods are established, and numerical assessments are conducted to illustrate the finite sample performance of our methods.

  18. Lamb-shift and electric field measurements in plasmas

    NASA Astrophysics Data System (ADS)

    Doveil, F.; Chérigier-Kovacic, L.; Ström, P.

    2017-01-01

    The electric field is a quantity of particular relevance in plasma physics. Indeed, its fluctuations are responsible for different macroscopic phenomena such as anomalous transport in fusion plasmas. Answering a long-standing challenge, we offer a new method to locally and non-intrusively measure weak electric fields and their fluctuations in plasmas, by means of a beam of hydrogen ions or atoms. We present measurements of the electric field in vacuum and in a plasma where Debye shielding is measured. For the first time, we have used the Lamb-shift resonance to measure oscillating electric fields around 1 GHz and observed the strong enhancement of the Lyman-α signal. The measurement is both direct and non-intrusive. This method provides sensitivity (mV cm-1) and temporal resolution (ns) that are three orders higher compared to current diagnostics. It thus allows measuring fluctuations of the electric field at scales not previously reached experimentally.

  19. Measurements of Magnetic Fields in the Solar Nebula

    NASA Astrophysics Data System (ADS)

    Fu, R. R.; Andrade Lima, E.; Weiss, B. P.

    2013-12-01

    Efficient radial transfer of angular momentum in the protoplanetary disk is a fundamental requirement for the formation of stars and planets. Theoretical work indicates that magnetic fields may have played a critical role in this process. For example, the magnetorotational instability (MRI) may have generated turbulence in the gas medium to facilitate angular momentum transport. Direct measurements of the magnetic field in the protoplanetary disk are necessary for evaluating the relative importance of this and other proposed mechanisms of angular momentum transport. Such fields could have been recorded by chondrules, millimeter-sized meteoritic inclusions that formed during flash-melting of nebular dust. We performed the first detailed paleomagnetic experiments on isolated chondrules from a primitive meteorite, the LL3.0 chondrite Semarkona. This meteorite has escaped extensive post-accretional aqueous alteration and metamorphism to above ~200 C, implying the preservation of primary ferromagnetic phases and pre-accretional magnetic remanence. We applied alternating field (AF) demagnetization up to 290 mT to bulk (mixed matrix and chondrule) samples and to isolated chondrules that contain dusty olivine grains, which are relict silicates that contain abundant low-Ni α-Fe (kamacite) grains in the single domain and pseudo-single domain size ranges. All samples were mutually oriented within 5 deg. Chondrule samples were measured using the SQUID Microscope in the MIT Paleomagnetism Laboratory. Bulk samples within ~4.5 mm of the fusion crust carry a unidirectional, medium-coercivity (MC) component of magnetization that decays in intensity with increasing distance from the fusion crust. We therefore attribute the MC component to atmospheric heating. This fusion crust baked contact test establishes that our sample has not been significantly remagnetized since arrival on Earth. One dusty olivine-bearing chondrule carries a stable high-coercivity (HC) component of

  20. Measuring the Earth's Magnetic Field in a Laboratory

    ERIC Educational Resources Information Center

    Cartacci, A.; Straulino, S.

    2008-01-01

    Two methods for measuring the Earth's magnetic field are described. In the former, according to Gauss, the Earth's magnetic field is compared with that of a permanent magnet; in the latter, a well-known method, the comparison is made with the magnetic field generated by a current. As all the used instruments are available off the shelf, both…

  1. High-resolution near-field measurements of microwave circuits

    NASA Astrophysics Data System (ADS)

    Kantor, R.; Shvets, I. V.

    2004-04-01

    In this paper we report on measurements of electric field intensities of microwave field above surface of microwave circuits using miniaturized coaxial antennas. During the scanning process the antenna is driven at various distances above the sample surface according to topographic data acquired prior to the field measurement. A position/signal difference method is used to increase the spatial resolution of the antenna to about 20 μm (λ/104) -- one order of magnitude better than contemporary microwave scanning systems. For measurement of the tangential field components parallel to the sample surface the antenna is tilted by about 45° relative to the sample surface. By its rotation about the vertical axis various components of the field are measured, vertical and horizontal electric field intensities are recalculated. Performance of our scanning system utilizing these methods is tested using a PCB surface capacitor, a microstrip filter and a microstrip transmission line.

  2. Field power measurements of imaging equipment

    SciTech Connect

    McWhinney, Marla; Homan, Gregory; Brown, Richard; Roberson, Judy; Nordman, Bruce; Busch, John

    2004-05-14

    According to the U.S. Department of Energy, electricity use by non-PC commercial office equipment is growing at an annual rate of nearly 5 percent (AEO 2003). To help address this growth in consumption, U.S. EPA periodically updates its ENERGY STAR specifications as products and markets change. This report presents background research conducted to help EPA update the ENERGY STAR specification for imaging equipment, which covers printers, fax machines, copiers, scanners, and multifunction devices (MFDs). We first estimated the market impact of the current ENERGY STAR imaging specification, finding over 90 percent of the current market complies with the specification. We then analyzed a sample of typical new imaging products, including 11 faxes, 57 printers and 19 copiers/MFD. For these devices we metered power levels in the most common modes: active/ready/sleep/off, and recorded features that would most likely affect energy consumption. Our metering indicates that for many products and speed bins, current models consume substantially less power than the current specification. We also found that for all product categories, power consumption varied most considerably across technology (i.e. inkjet vs. laser). Although inkjet printers consumed less energy than laser printers in active, ready and sleep-mode, they consumed more power on average while off, mostly due to the use of external power supplies. Based on these findings, we developed strategies for the ENERGY STAR program to achieve additional energy reductions. Finally, we present an assessment of manufacturer's ENERGY STAR labeling practices.

  3. Simultaneous measurement of nanoscale electric and magnetic optical fields

    NASA Astrophysics Data System (ADS)

    Le Feber, B.; Rotenberg, N.; Beggs, D. M.; Kuipers, L.

    2014-01-01

    Control of light-matter interactions at the nanoscale has advanced fields such as quantum optics, photovoltaics and telecommunications. These advances are driven by an improved understanding of the nanoscale behaviour of light, enabled by direct observations of the local electric fields near photonic nanostructures. With the advent of metamaterials that respond to the magnetic component of light, schemes have been developed to measure the nanoscale magnetic field. However, these structures interact not only with the magnetic field, but also with the electric field of light. Here, we demonstrate the essential simultaneous detection of both electric and magnetic fields with subwavelength resolution. By explaining our measurements through reciprocal considerations, we create a route towards designing probes sensitive to specific desired combinations of electric and magnetic field components. Simultaneous access to nanoscale electric and magnetic fields will pave the way for new designs of optical nanostructures and metamaterials.

  4. Evaluation of uncertainty in the measurement of environmental electromagnetic fields.

    PubMed

    Vulević, B; Osmokrović, P

    2010-09-01

    With regard to Non-ionising radiation protection, the relationship between human exposure to electromagnetic fields and health is controversial. Electromagnetic fields have become omnipresent in the daily environment. This paper assesses the problem of how to compare a measurement result with a limit fixed by the standard for human exposure to electric, magnetic and electromagnetic fields (0 Hz-300 GHz). The purpose of the paper is an appropriate representation of the basic information about evaluation of measurement uncertainty.

  5. Molecular-scale measurements of electric fields at electrochemical interfaces.

    SciTech Connect

    Hayden, Carl C.; Farrow, Roger L.

    2011-01-01

    Spatially resolved measurements of electric fields at electrochemical interfaces would be a critical step toward further understanding and modeling the detailed structure of electric double layers. The goal of this project was to perform proof-of-principle experiments to demonstrate the use of field-sensitive dyes for optical measurements of fields in electrochemical systems. A confocal microscope was developed that provides sensitive detection of the lifetime and high resolution spectra of excited fluorescence for dyes tethered to electrically conductive surfaces. Excited state lifetimes for the dyes were measured and found to be relatively unquenched when linked to indium tin oxide, but strongly quenched on gold surfaces. However, our fluorescence detection is sufficiently sensitive to measure spectra of submonolayer dye coatings even when the fluorescence was strongly quenched. Further work to create dye labeled interfaces on flat, uniform and durable substrates is necessary to make electric field measurements at interfaces using field sensitive dyes.

  6. Analysis of occupational accidents: prevention through the use of additional technical safety measures for machinery

    PubMed Central

    Dźwiarek, Marek; Latała, Agata

    2016-01-01

    This article presents an analysis of results of 1035 serious and 341 minor accidents recorded by Poland's National Labour Inspectorate (PIP) in 2005–2011, in view of their prevention by means of additional safety measures applied by machinery users. Since the analysis aimed at formulating principles for the application of technical safety measures, the analysed accidents should bear additional attributes: the type of machine operation, technical safety measures and the type of events causing injuries. The analysis proved that the executed tasks and injury-causing events were closely connected and there was a relation between casualty events and technical safety measures. In the case of tasks consisting of manual feeding and collecting materials, the injuries usually occur because of the rotating motion of tools or crushing due to a closing motion. Numerous accidents also happened in the course of supporting actions, like removing pollutants, correcting material position, cleaning, etc. PMID:26652689

  7. Advanced materials characterization based on full field deformation measurements

    NASA Astrophysics Data System (ADS)

    Carpentier, A. Paige

    Accurate stress-strain constitutive properties are essential for understanding the complex deformation and failure mechanisms for materials with highly anisotropic mechanical properties. Among such materials, glass-fiber- and carbon-fiber-reinforced polymer--matrix composites play a critical role in advanced structural designs. The large number of different methods and specimen types currently required to generate three-dimensional allowables for structural design slows down the material characterization. Also, some of the material constitutive properties are never measured due to the prohibitive cost of the specimens needed. This work shows that simple short-beam shear (SBS) specimens are well-suited for measurement of multiple constitutive properties for composite materials and that can enable a major shift toward accurate material characterization. The material characterization is based on the digital image correlation (DIC) full-field deformation measurement. The full-field-deformation measurement enables additional flexibility for assessment of stress--strain relations, compared to the conventional strain gages. Complex strain distributions, including strong gradients, can be captured. Such flexibility enables simpler test-specimen design and reduces the number of different specimen types required for assessment of stress--strain constitutive behavior. Two key elements show advantage of using DIC in the SBS tests. First, tensile, compressive, and shear stress--strain relations are measured in a single experiment. Second, a counter-intuitive feasibility of closed-form stress and modulus models, normally applicable to long beams, is demonstrated for short-beam specimens. The modulus and stress--strain data are presented for glass/epoxy and carbon/epoxy material systems. The applicability of the developed method to static, fatigue, and impact load rates is also demonstrated. In a practical method to determine stress-strain constitutive relations, the stress

  8. Pairwise-additive force fields for selected aqueous monovalent ions from adaptive force matching

    PubMed Central

    Li, Jicun; Wang, Feng

    2015-01-01

    Simple non-polarizable potentials were developed for Na+, K+, Cl−, and Br− using the adaptive force matching (AFM) method with ab initio MP2 method as reference. Our MP2-AFM force field predicts the solvation free energies of the four salts formed by the ions with an error of no more than 5%. Other properties such as the ion-water radial distribution functions, first solvation shell water tilt angle distributions, ion diffusion constants, concentration dependent diffusion constant of water, and concentration dependent surface tension of the solutions were calculated with this potential. Very good agreement was achieved for these properties. In particular, the diffusion constants of the ions are within 6% of experimental measurements. The model predicts bromide to be enriched at the interface in the 1.6M KBr solution but predicts the ion to be repelled for the surface at lower concentration. PMID:26590540

  9. 49 CFR 192.935 - What additional preventive and mitigative measures must an operator take?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... accordance with one of the risk assessment approaches in ASME/ANSI B31.8S (incorporated by reference, see § 192.7), section 5, a risk analysis of its pipeline to identify additional measures to protect the high.... (2) Outside force damage. If an operator determines that outside force (e.g., earth movement,...

  10. 49 CFR 192.935 - What additional preventive and mitigative measures must an operator take?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... accordance with one of the risk assessment approaches in ASME/ANSI B31.8S (incorporated by reference, see § 192.7), section 5, a risk analysis of its pipeline to identify additional measures to protect the high.... (2) Outside force damage. If an operator determines that outside force (e.g., earth movement,...

  11. New Limits on Extragalactic Magnetic Fields from Rotation Measures

    NASA Astrophysics Data System (ADS)

    Pshirkov, M. S.; Tinyakov, P. G.; Urban, F. R.

    2016-05-01

    We take advantage of the wealth of rotation measures data contained in the NRAO VLA Sky Survey catalog to derive new, statistically robust, upper limits on the strength of extragalactic magnetic fields. We simulate the extragalactic magnetic field contribution to the rotation measures for a given field strength and correlation length, by assuming that the electron density follows the distribution of Lyman-α clouds. Based on the observation that rotation measures from distant radio sources do not exhibit any trend with redshift, while the extragalactic contribution instead grows with distance, we constrain fields with Jeans' length coherence length to be below 1.7 nG at the 2 σ level, and fields coherent across the entire observable Universe below 0.65 nG. These limits do not depend on the particular origin of these cosmological fields.

  12. [A focused sound field measurement system by LabVIEW].

    PubMed

    Jiang, Zhan; Bai, Jingfeng; Yu, Ying

    2014-05-01

    In this paper, according to the requirement of the focused sound field measurement, a focused sound field measurement system was established based on the LabVIEW virtual instrument platform. The system can automatically search the focus position of the sound field, and adjust the scanning path according to the size of the focal region. Three-dimensional sound field scanning time reduced from 888 hours in uniform step to 9.25 hours in variable step. The efficiency of the focused sound field measurement was improved. There is a certain deviation between measurement results and theoretical calculation results. Focal plane--6 dB width difference rate was 3.691%, the beam axis--6 dB length differences rate was 12.937%.

  13. Mass spectra in N=1 SQCD with additional colorless but flavored fields

    NASA Astrophysics Data System (ADS)

    Chernyak, Victor L.

    2017-01-01

    Considered is the N=1 supersymmetric QCD-like Φ -theory with SU(N_c) colors and 0< N_F<2N_c flavors of light quarks Q^i_a,{overline{Q}}^{ a}_j with equal small masses. In addition to quarks and gluons of the standard N=1 SQCD, it includes N^2_F colorless but flavored fields Φ ij, with the large mass parameter μ _{Φ } ≫ Λ _Q (Λ _Q is the scale factor of the gauge coupling), interacting with quarks through the Yukawa coupling in the superpotential. The mass spectra of this (direct) Φ -theory are first directly calculated in all vacua with the unbroken or spontaneously broken flavor symmetry U(N_F)→ U(n_1)× U(n_2) at 0fields Φ `turn back' and there appear two additional generations of light Φ -particles with small masses μ ^pole(Φ )≪ Λ _Q. Also considered is the X-theory which is the N=2 SQCD with SU(N_c) colors and 0< N_F<2N_c flavors of light quarks, broken down to N=1 by the large mass

  14. Study raises questions about measurement of 'additionality,'or maintaining domestic health spending amid foreign donations.

    PubMed

    Garg, Charu C; Evans, David B; Dmytraczenko, Tania; Izazola-Licea, José-Antonio; Tangcharoensathien, Viroj; Ejeder, Tessa Tan-Torres

    2012-02-01

    Donor nations and philanthropic organizations increasingly require that funds provided for a specific health priority such as HIV should supplement domestic spending on that priority-a concept known as "additionality." We investigated the "additionality" concept using data from Honduras, Rwanda, and Thailand, and we found that the three countries increased funding for HIV in response to increased donor funding. In contrast, the study revealed that donors, faced with increased Global Fund resources for HIV in certain countries, tended to decrease their funding for HIV or shift funds for use in non-HIV health areas. More broadly, we found many problems in the measurement and interpretation of additionality. These findings suggest that it would be preferable for donors and countries to agree on how best to use available domestic and external funds to improve population health, and to develop better means of tracking outcomes, than to try to develop more sophisticated methods to track additionality.

  15. Mean-square error due to gradiometer field measuring devices.

    PubMed

    Hatsell, C P

    1991-06-01

    Gradiometers use spatial common mode magnetic field rejection to reduce interference from distant sources. They also introduce distortion that can be severe, rendering experimental data difficult to interpret. Attempts to recover the measured magnetic field from the gradiometer output will be plagued by the nonexistence of a spatial function for deconvolution (except for first-order gradiometers), and by the high-pass nature of the spatial transform that emphasizes high spatial frequency noise. Goals of a design for a facility for measuring biomagnetic fields should be an effective shielded room and a field detector employing a first-order gradiometer.

  16. Measurement of the gravity-field curvature by atom interferometry.

    PubMed

    Rosi, G; Cacciapuoti, L; Sorrentino, F; Menchetti, M; Prevedelli, M; Tino, G M

    2015-01-09

    We present the first direct measurement of the gravity-field curvature based on three conjugated atom interferometers. Three atomic clouds launched in the vertical direction are simultaneously interrogated by the same atom interferometry sequence and used to probe the gravity field at three equally spaced positions. The vertical component of the gravity-field curvature generated by nearby source masses is measured from the difference between adjacent gravity gradient values. Curvature measurements are of interest in geodesy studies and for the validation of gravitational models of the surrounding environment. The possibility of using such a scheme for a new determination of the Newtonian constant of gravity is also discussed.

  17. Species-Independent Femtosecond Localized Electric Field Measurement

    NASA Astrophysics Data System (ADS)

    Dogariu, Arthur; Goldberg, Benjamin M.; O'Byrne, Sean; Miles, Richard B.

    2017-02-01

    We present an optical measurement method using a femtosecond laser for nonintrusive measurements of electric field strength and orientation in virtually any gas or gas mixture via second-harmonic generation. This simple method takes advantage of the asymmetry in polarizability induced by an applied electric field, which enables the otherwise forbidden second-harmonic generation in any centrosymmetric or homogeneous media. The use of a femtosecond laser source permits high intensities without avalanche breakdown and leads to the measurement of electric field strength down to approximately 100 V / cm in air with submillimeter spatial resolution governed by the confocal parameter and femtosecond temporal resolution governed by the laser-pulse duration.

  18. Electro-optic probe measurements of electric fields in plasmas.

    PubMed

    Nishiura, M; Yoshida, Z; Mushiake, T; Kawazura, Y; Osawa, R; Fujinami, K; Yano, Y; Saitoh, H; Yamasaki, M; Kashyap, A; Takahashi, N; Nakatsuka, M; Fukuyama, A

    2017-02-01

    The direct measurements of high-frequency electric fields in a plasma bring about significant advances in the physics and engineering of various waves. We have developed an electro-optic sensor system based on the Pockels effect. Since the signal is transmitted through an optical fiber, the system has high tolerance for electromagnetic noises. To demonstrate its applicability to plasma experiments, we report the first result of measurement of the ion-cyclotron wave excited in the RT-1 magnetosphere device. This study compares the results of experimental field measurements with simulation results of electric fields in plasmas.

  19. Electro-optic probe measurements of electric fields in plasmas

    NASA Astrophysics Data System (ADS)

    Nishiura, M.; Yoshida, Z.; Mushiake, T.; Kawazura, Y.; Osawa, R.; Fujinami, K.; Yano, Y.; Saitoh, H.; Yamasaki, M.; Kashyap, A.; Takahashi, N.; Nakatsuka, M.; Fukuyama, A.

    2017-02-01

    The direct measurements of high-frequency electric fields in a plasma bring about significant advances in the physics and engineering of various waves. We have developed an electro-optic sensor system based on the Pockels effect. Since the signal is transmitted through an optical fiber, the system has high tolerance for electromagnetic noises. To demonstrate its applicability to plasma experiments, we report the first result of measurement of the ion-cyclotron wave excited in the RT-1 magnetosphere device. This study compares the results of experimental field measurements with simulation results of electric fields in plasmas.

  20. Size characterization by Sedimentation Field Flow Fractionation of silica particles used as food additives.

    PubMed

    Contado, Catia; Ravani, Laura; Passarella, Martina

    2013-07-25

    Four types of SiO2, available on the market as additives in food and personal care products, were size characterized using Sedimentation Field Flow Fractionation (SdFFF), SEM, TEM and Photon Correlation Spectroscopy (PCS). The synergic use of the different analytical techniques made it possible, for some samples, to confirm the presence of primary nanoparticles (10 nm) organized in clusters or aggregates of different dimension and, for others, to discover that the available information is incomplete, particularly that regarding the presence of small particles. A protocol to extract the silica particles from a simple food matrix was set up, enriching (0.25%, w w(-1)) a nearly silica-free instant barley coffee powder with a known SiO2 sample. The SdFFF technique, in conjunction with SEM observations, made it possible to identify the added SiO2 particles and verify the new particle size distribution. The SiO2 content of different powdered foodstuffs was determined by graphite furnace atomic absorption spectroscopy (GFAAS); the concentrations ranged between 0.006 and 0.35% (w w(-1)). The protocol to isolate the silica particles was so applied to the most SiO2-rich commercial products and the derived suspensions were separated by SdFFF; SEM and TEM observations supported the size analyses while GFAAS determinations on collected fractions permitted element identification.

  1. Separation of field-independent and field-dependent susceptibility tensors using a sequence of fully automated AMS measurements

    NASA Astrophysics Data System (ADS)

    Studynka, J.; Chadima, M.; Hrouda, F.; Suza, P.

    2013-12-01

    Low-field magnetic susceptibility of diamagnetic and paramagnetic minerals as well as that of pure magnetite and all single-domain ferromagnetic (s.l.) minerals is field-independent. In contrast, magnetic susceptibility of multi-domain pyrrhotite, hematite and titanomagnetite may significantly depend on the field intensity. Hence, the AMS data acquired in various fields have a great potential to separate the magnetic fabric carried by the latter group of minerals from the whole-rock fabric. The determination of the field variation of AMS consist of separate measurements of each sample in several fields within the Rayleigh Law range and subsequent processing in which the field-independent and field-dependent susceptibility tensors are calculated. The disadvantage of this technique is that each sample must be measured several times in various positions, which is relatively laborious and time consuming. Recently, a new 3D rotator was developed for the MFK1 Kappabridges which rotates the sample simultaneously about two axes with different velocities. The measurement is fully automated in such a way that, once the sample is mounted into the rotator, it requires no additional positioning to measure the full AMS tensor. The important advantage of the 3D rotator is that it enables to measure AMS in a sequence of pre-set field intensities without any operator manipulation. Whole procedure is computer-controlled and, once a sequence of measurements is finished, the acquired data are immediately processed and visualized. Examples of natural rocks demonstrating various types of field dependence of AMS are given.

  2. Methods of Measuring Vapor Pressures of Lubricants With Their Additives Using TGA and/or Microbalances

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.; Miller, Michael K.; Montoya, Alex F.

    1996-01-01

    The life of a space system may be critically dependent on the lubrication of some of its moving parts. The vapor pressure, the quantity of the available lubricant, the temperature and the exhaust venting conductance passage are important considerations in the selection and application of a lubricant. In addition, the oil additives employed to provide certain properties of low friction, surface tension, antioxidant and load bearing characteristics, are also very important and need to be known with regard to their amounts and vapor pressures. This paper reports on the measurements and analyses carried out to obtain those parameters for two often employed lubricants, the Apiezon(TM)-C and the Krytox(TM) AB. The measurements were made employing an electronic microbalance and a thermogravimetric analyzer (TGA) modified to operate in a vacuum. The results have been compared to other data on these oils when available. The identification of the mass fractions of the additives in the oil and their vapor pressures as a function of the temperature were carried out. These may be used to estimate the lubricant life given its quantity and the system vent exhaust conductance. It was found that the Apiezon(TM)-C has three main components with different rates of evaporation while the Krytox(TM) did not indicate any measurable additive.

  3. Recent measurements of middle atmospheric electric fields and related parameters

    NASA Astrophysics Data System (ADS)

    Zadorozhny, A. M.; Tyutin, A. A.; Bragin, O. A.; Kikhtenko, V. N.

    1994-03-01

    In 1989, two series of rocket measurements were carried out to investigate middle atmosphere electric fields. The measurements were taken both in the Northern Hemisphere on Heiss Island (80 deg 37 N and 58 deg 03 min E) and in the Southern Hemisphere in the Indian Ocean (40-60 deg S and approx. 45 deg E) on board the research vessel 'Akademik Shirshov'. Along with the vertical electric fields, aerosol content and positive ion density were also measured. Some of the rocket launches were made during the extremely strong solar proton events (SPE) of October 1989. The experiments showed the strong variability of the electric fields in the middle atmosphere at polar and high middle latitudes. In all the measurements the maximum of the vertical electric field height profile in the lower mesosphere was observed to be more than approx. 1 V/m. The electric field strength and the field direction at maximum varied considerably among the launches. A maximum value of +12 V/m was detected at a height of about 58 km at 58 deg 30 mins on 21 October 1989 during the SPE. The simultaneous measurements of the electric field strength, positive ion density and aerosols point out both an ion-aerosol interaction and a connection between the mesospheric electric fields and aerosol content.

  4. Magnetic field models of nine CP stars from "accurate" measurements

    NASA Astrophysics Data System (ADS)

    Glagolevskij, Yu. V.

    2013-01-01

    The dipole models of magnetic fields in nine CP stars are constructed based on the measurements of metal lines taken from the literature, and performed by the LSD method with an accuracy of 10-80 G. The model parameters are compared with the parameters obtained for the same stars from the hydrogen line measurements. For six out of nine stars the same type of structure was obtained. Some parameters, such as the field strength at the poles B p and the average surface magnetic field B s differ considerably in some stars due to differences in the amplitudes of phase dependences B e (Φ) and B s (Φ), obtained by different authors. It is noted that a significant increase in the measurement accuracy has little effect on the modelling of the large-scale structures of the field. By contrast, it is more important to construct the shape of the phase dependence based on a fairly large number of field measurements, evenly distributed by the rotation period phases. It is concluded that the Zeeman component measurement methods have a strong effect on the shape of the phase dependence, and that the measurements of the magnetic field based on the lines of hydrogen are more preferable for modelling the large-scale structures of the field.

  5. Radiative corrections to the Higgs boson couplings in the model with an additional real singlet scalar field

    NASA Astrophysics Data System (ADS)

    Kanemura, Shinya; Kikuchi, Mariko; Yagyu, Kei

    2016-06-01

    We calculate renormalized Higgs boson couplings with gauge bosons and fermions at the one-loop level in the model with an additional isospin singlet real scalar field. These coupling constants can deviate from the predictions in the standard model due to tree-level mixing effects and one-loop contributions of the extra neutral scalar boson. We investigate how they can be significant under the theoretical constraints from perturbative unitarity and vacuum stability and also the condition of avoiding the wrong vacuum. Furthermore, comparing with the predictions in the Type I two Higgs doublet model, we numerically demonstrate how the singlet extension model can be distinguished and identified by using precision measurements of the Higgs boson couplings at future collider experiments.

  6. Lake-Atmosphere Turbulent EXchanges (LATEX) field measurement campaign

    NASA Astrophysics Data System (ADS)

    Bou-Zeid, E.; Huwald, H.; Lemmin, U.; Selker, J.; Parlange, M. B.

    2006-12-01

    High resolution measurements of surface fluxes in the atmospheric boundary layer over water surfaces are less common than over land. Nevertheless, developing our understanding of air-water interaction is crucial for improving evaporation models, developing and testing surface parameterizations in meso-scale and global circulation models, and understanding local atmospheric dynamics over water. The Lake-Atmosphere Turbulent EXchanges (LATEX) field measurement campaign was designed to address these issues. The experiment took place on a platform in Lake Geneva in Switzerland (exposed to a 30 km long wind fetch) over the period extending from August through October of 2006. The primary instrumentation consisted of: 1) a vertical array of four sonic anemometers and four open-path H2O/CO2 analyzers, 2) a Raman scattering fiber- optic temperature profiler having a resolution of 4-mm vertically and 0.01 deg C in temperature (3 meter range: 1 meter above the water surface and 2 meters below), and 3) a lake current profiler. Additional supporting measurements included net radiation, surface temperature, relative humidity, wave height and speed, as well as several point-measurements of air and water temperature. We present results for fluxes of momentum, heat, water vapor, and CO2 and test flux-profiles relations (derived from Monin-Obukhov similarity) that are frequently used to estimate these fluxes. Different formulations for roughness and scalar lengths are tested for different lake surface conditions. Finally, we look at small scale turbulence over the lake by computing the eddy-viscosity, the turbulent Prandtl number, and turbulent Schmidt numbers for water vapor and CO2 at scales comparable to large eddy simulation (LES) grid scales; these results can be used to prescribe model coefficient a priori in LES or to test the performance of various dynamic models in reproducing the correct sub-grid scale fluxes.

  7. A measurement system applicable for landslide experiments in the field.

    PubMed

    Guo, Wen-Zhao; Xu, Xiang-Zhou; Wang, Wen-Long; Yang, Ji-Shan; Liu, Ya-Kun; Xu, Fei-Long

    2016-04-01

    Observation of gravity erosion in the field with strong sunshine and wind poses a challenge. Here, a novel topography meter together with a movable tent addresses the challenge. With the topography meter, a 3D geometric shape of the target surface can be digitally reconstructed. Before the commencement of a test, the laser generator position and the camera sightline should be adjusted with a sight calibrator. Typically, the topography meter can measure the gravity erosion on the slope with a gradient of 30°-70°. Two methods can be used to obtain a relatively clear video, despite the extreme steepness of the slopes. One method is to rotate the laser source away from the slope to ensure that the camera sightline remains perpendicular to the laser plane. Another way is to move the camera farther away from the slope in which the measured volume of the slope needs to be corrected; this method will reduce distortion of the image. In addition, installation of tent poles with concrete columns helps to surmount the altitude difference on steep slopes. Results observed by the topography meter in real landslide experiments are rational and reliable.

  8. A measurement system applicable for landslide experiments in the field

    NASA Astrophysics Data System (ADS)

    Guo, Wen-Zhao; Xu, Xiang-Zhou; Wang, Wen-Long; Yang, Ji-Shan; Liu, Ya-Kun; Xu, Fei-Long

    2016-04-01

    Observation of gravity erosion in the field with strong sunshine and wind poses a challenge. Here, a novel topography meter together with a movable tent addresses the challenge. With the topography meter, a 3D geometric shape of the target surface can be digitally reconstructed. Before the commencement of a test, the laser generator position and the camera sightline should be adjusted with a sight calibrator. Typically, the topography meter can measure the gravity erosion on the slope with a gradient of 30°-70°. Two methods can be used to obtain a relatively clear video, despite the extreme steepness of the slopes. One method is to rotate the laser source away from the slope to ensure that the camera sightline remains perpendicular to the laser plane. Another way is to move the camera farther away from the slope in which the measured volume of the slope needs to be corrected; this method will reduce distortion of the image. In addition, installation of tent poles with concrete columns helps to surmount the altitude difference on steep slopes. Results observed by the topography meter in real landslide experiments are rational and reliable.

  9. Magnetic field measurements using the transient internal probe (TIP)

    SciTech Connect

    Galambos, J.P.; Bohnet, M.A.; Jarboe, T.R.; Mattick, A.T.

    1995-12-31

    Knowledge of the internal magnetic field profile in hot plasmas is fundamental to understanding the structure and behavior of the current profile. The transient internal probe (TIP) is a novel diagnostic designed to measure internal magnetic fields in hot plasmas. The diagnostic involves shooting a magneto-optic probe through the plasma at high velocities (greater than 2 km/s) using a two stage light gas gun. Local fields are obtained by illuminating the probe with an argon ion laser and measuring the amount of Faraday rotation in the reflected beam. Initial development of the diagnostic is complete. Results of magnetic field measurements conducted at 2 km/s will be presented. Helium muzzle gas introduction to the plasma chamber has been limited to less than 0.4 Torr-{ell}. Magnetic field resolution of 40 Gauss and spatial resolution of 5 mm have been achieved. System frequency response is 10 MHz.

  10. Magnetic-field measurements for the Lewis Research Center cyclotron

    NASA Technical Reports Server (NTRS)

    Fessler, T. E.

    1973-01-01

    The magnetic field of the Lewis Center cyclotron was mapped by using a Hall-effect magnetic-field transducer. Main-field Fourier coefficients were determined on a polar mesh of 40 radii for each of seven levels of main-field coil current. Incremental fields for eight sets of trim coils and two sets of harmonic coils were also determined at four of these main-field levels. A stored-program, digital computer was used to perform the measurements. The process was entirely automatic; all data-taking and data-reduction activities were specified by the computer programs. A new method for temperature compensation of a Hall element was used. This method required no temperature control of the element. Measurements of the Hall voltage and Hall-element resistance were sufficient to correct for temperature effects.

  11. 47 CFR 73.686 - Field strength measurements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... antenna impedance to the transmission line at all frequencies measured, and, if using an unbalanced line... transmission line between the testing antenna and the field strength meter. Match the antenna impedance to...

  12. 47 CFR 73.686 - Field strength measurements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... antenna impedance to the transmission line at all frequencies measured, and, if using an unbalanced line... transmission line between the testing antenna and the field strength meter. Match the antenna impedance to...

  13. A quantitative measure of phase correlations in density fields

    NASA Technical Reports Server (NTRS)

    Scherrer, Robert J.; Melott, Adrian L.; Shandarin, Sergei F.

    1991-01-01

    A quantitative measure of the phase correlations in a density field is presented based on the location of the maxima of the Fourier components of that field. It is found that this measue can easily detect non-Gaussian behavior either in artificially constructed density fields or those that become non-Gaussian from gravitational clustering of Gaussian initial conditions. It is found that different initial power spectra produce somewhat distinguishable signals, and the signals are robust against sparse sampling.

  14. Altimeter measurements for the determination of the Earth's gravity field

    NASA Technical Reports Server (NTRS)

    Tapley, B. D.; Schutz, B. E.; Shum, C. K.

    1986-01-01

    Progress in the following areas is described: refining altimeter and altimeter crossover measurement models for precise orbit determination and for the solution of the earth's gravity field; performing experiments using altimeter data for the improvement of precise satellite ephemerides; and analyzing an optimal relative data weighting algorithm to combine various data types in the solution of the gravity field.

  15. Online measurement of bead geometry in GMAW-based additive manufacturing using passive vision

    NASA Astrophysics Data System (ADS)

    Xiong, Jun; Zhang, Guangjun

    2013-11-01

    Additive manufacturing based on gas metal arc welding is an advanced technique for depositing fully dense components with low cost. Despite this fact, techniques to achieve accurate control and automation of the process have not yet been perfectly developed. The online measurement of the deposited bead geometry is a key problem for reliable control. In this work a passive vision-sensing system, comprising two cameras and composite filtering techniques, was proposed for real-time detection of the bead height and width through deposition of thin walls. The nozzle to the top surface distance was monitored for eliminating accumulated height errors during the multi-layer deposition process. Various image processing algorithms were applied and discussed for extracting feature parameters. A calibration procedure was presented for the monitoring system. Validation experiments confirmed the effectiveness of the online measurement system for bead geometry in layered additive manufacturing.

  16. Measuring Helical FCG Voltage with an Electric Field Antenna

    SciTech Connect

    White, A D; Anderson, R A; Javedani, J B; Reisman, D B; Goerz, D A; Ferriera, A J; Speer, R D

    2011-08-01

    A method of measuring the voltage produced by a helical explosive flux compression generator using a remote electric field antenna is described in detail. The diagnostic has been successfully implemented on several experiments. Measured data from the diagnostic compare favorably with voltages predicted using the code CAGEN, validating our predictive modeling tools. The measured data is important to understanding generator performance, and is measured with a low-risk, minimally intrusive approach.

  17. Measurement of magnetic field using Rayleigh backscattering in optical fibres

    SciTech Connect

    Wuilpart, M.; Caucheteur, C.; Goussarov, A.; Aerssens, M.; Massaut, V.; Megret, P.

    2011-07-01

    In this paper, we investigate the use of optical reflectometry in optical fibres for the measurement of magnetic field. The dedicated application concerns the measurement of plasma current in the fusion reactor. The measurement is based on the rotation of the polarization state of the Rayleigh backscattered signal when an optical pulse is launched in the fibre. Particular care has been undertaken to evaluate the impact of linear birefringence on the measurement performance. (authors)

  18. Antenna gain measurements in the intermediate-field zone

    NASA Astrophysics Data System (ADS)

    Anchidin, Liliana; Bari, Farida; Dumitrascu, Ana; Paun, Mirel; Deacu, Daniela; Tasu, Sorin; Danisor, Alin; Tamas, Razvan D.

    2016-12-01

    Antenna gain is usually evaluated under far-field conditions. Furthermore, Friis transmission formula can solely be applied when antenna size can be neglected with respect to the distance between the measuring antenna and the antenna under test. In this paper, we show that by applying the distance averaging technique the far-field and antenna size constraints can be overcome. Our method was validated by measuring a monopole antenna and a Vivaldi antenna in an open area test site (OATS).

  19. Experimental Validation of Simulations Using Full-field Measurement Techniques

    SciTech Connect

    Hack, Erwin

    2010-05-28

    The calibration by reference materials of dynamic full-field measurement systems is discussed together with their use to validate numerical simulations of structural mechanics. The discussion addresses three challenges that are faced in these processes, i.e. how to calibrate a measuring instrument that (i) provides full-field data, and (ii) is dynamic; (iii) how to compare data from simulation and experimentation.

  20. Filtered Rayleigh Scattering Measurements in a Buoyant Flow Field

    DTIC Science & Technology

    2008-03-01

    John William Strutt , the third Baron of Rayleigh , or more commonly known as Lord Rayleigh , was the first to offer a correct explanation of the...FILTERED RAYLEIGH SCATTERING MEASUREMENTS IN A BUOYANT FLOW FIELD         THESIS       Steven Michael Meents, Captain, USAF...AFIT/GAE/ENY/08-M22 FILTERED RAYLEIGH SCATTERING MEASUREMENTS IN A BUOYANT FLOW FIELD THESIS Presented to the Faculty Department of Aeronautics

  1. Measuring Coronal Magnetic Fields with Coronal Emission Line Polarimetry

    NASA Astrophysics Data System (ADS)

    Lin, H.

    2003-12-01

    Magnetic field is the dominating field in the solar corona, responsible for the majestic coronal structures and dynamic events. However, no direct measurements of the coronal magnetic fields are routinely available and we can only infer the coronal magnetic field structures from observed intensity images. Although several methods for the diagnostics of coronal magnetic fields have been demonstrated, measurement of the coronal magnetic fields remains a very challenging observational task. This paper reports on a concerted effort at the Institute for Astronomy (IfA) to establish routine vector coronal magnetic field measurement capabilities using spectropolarimetric observation of the near infrared Fe XIII 1074.7 nm coronal emission line. The IfA effort includes observations of two-dimensional circular polarization maps of the emission line which carry information about the coronal magnetic field strength. High resolution observation of the linear polarization maps which yield the projected direction of the coronal magnetic field in the plane of the sky will also be obtained. The latest results from these experiments will be presented.

  2. Ion trap electric field measurements using slab coupled optical sensors

    NASA Astrophysics Data System (ADS)

    Shumway, L.; Chadderdon, S.; Powell, A.; Li, A.; Austin, D.; Hawkins, A.; Selfridge, R.; Schultz, S.

    2014-03-01

    Ion traps are widely used in the field of mass spectrometry. These devices use high electric fields to mass-selectively trap, eject, and count the particles of a material, producing a mass spectrum of the given material. Because of their usefulness, technology pushes for smaller, more portable ion traps for field use. Making internal ion trap field measurements not yet feasible because current electric field sensors are often too bulky or their metallic composition perturbs field measurements. Using slab coupled optical sensor (SCOS) technology, we are able to build sensors that are compatible with the spacing constraints of the ion trap. These sensors are created by attaching a nonlinear crystal slab waveguide to an optical fiber. When a laser propagates through the fiber, certain wavelengths of light couple out of the fiber via the crystal and create "resonances" in the output light spectrum. These resonances shift in proportion to a given applied electric field, and by measuring that shift, we can approximate the electric field. Developing a sensor that can effectively characterize the electric fields within an ion trap will greatly assist in ion trap design, fabrication, and troubleshooting techniques.

  3. Aircraft measurement of electric field - Self-calibration

    NASA Technical Reports Server (NTRS)

    Winn, W. P.

    1993-01-01

    Aircraft measurement of electric fields is difficult as the electrically conducting surface of the aircraft distorts the electric field. Calibration requires determining the relations between the undistorted electric field in the absence of the vehicle and the signals from electric field meters that sense the local distorted fields in their immediate vicinity. This paper describes a generalization of a calibration method which uses pitch and roll maneuvers. The technique determines both the calibration coefficients and the direction of the electric vector. The calibration of individual electric field meters and the elimination of the aircraft's self-charge are described. Linear combinations of field mill signals are examined and absolute calibration and error analysis are discussed. The calibration method was applied to data obtained during a flight near thunderstorms.

  4. Multichannel detectors for profile measurements in clinical proton fields

    SciTech Connect

    Nichiporov, Dmitri; Solberg, Keith; Hsi Wen; Wolanski, Mark; Mascia, Anthony; Farr, Jonathan; Schreuder, Andries

    2007-07-15

    Two beam profile measurement detectors have been developed at Indiana University Cyclotron Facility to address the need for a tool to efficiently verify dose distributions created with active methods of clinical proton beam delivery. The multipad ionization chamber (MPIC) has 128 ionization chambers arranged in one plane and is designed to measure lateral profiles in fields up to 38 cm in diameter. The MPIC pads have a 5 mm pitch for fields up to 20 cm in diameter and a 7 mm pitch for larger fields, providing the accuracy of field size determination about 0.5 mm. The multilayer ionization chamber (MLIC) detector contains 122 small-volume ionization chambers stacked at a 1.82 mm step (water-equivalent) for depth-dose profile measurements. The MLIC detector can measure profiles up to 20 cm in depth, and determine the 80% distal dose fall-off with about 0.1 mm precision. Both detectors can be connected to the same set of electronics modules, which comprise the detectors' data acquisition system. The detectors have been tested in clinical proton fields produced with active methods of beam delivery such as uniform scanning and energy stacking. This article describes detector performance tests and discusses their results. The test results indicate that the MPIC and MLIC detectors can be used for dosimetric characterization of clinical proton fields. The detectors offer significant time savings during measurements in actively delivered beams compared with traditional measurements using a water phantom.

  5. 76 FR 31823 - Technical Amendment to List of User Fee Airports: Addition of Dallas Love Field Municipal Airport...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ... Airports: Addition of Dallas Love Field Municipal Airport, Dallas, TX AGENCY: U.S. Customs and Border... revising the list of user fee airports to reflect the recent user fee airport designation for Dallas Love... of user fee status for Dallas Love Field Municipal Airport. This document updates the list of...

  6. LIF Diagnostic for Measuring Beam-Transport Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Jones, T. G.; Noonan, W. A.; Ottinger, P. F.

    1996-11-01

    A novel, spatially-resolved diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic technique uses laser-induced fluorescence (LIF) spectroscopy, and can be varied to measure either small or large fields. Small fields, as expected in ballistic transport with solenoidal lens focusing using ~ 1 Torr gas, produce Zeeman shifts, Δ λ_Z, smaller than the transition linewidth, Δ λ. High sensitivity to measure these shifts is achieved by a variation on the Babcock technique.^1 Large fields, as expected in self-pinched transport using 10--100 mTorr gas, produce Δ λZ larger than Δ λ, which can be measured with a high-resolution spectrometer. Results of proof-of-principle experiments using calibrated B-fields for both the small- and large-field techniques will be presented. Progress in fielding this diagnostic on the Gamble-II accelerator for beam-transport studies will also be presented. This work is supported by DoE through Sandia National Laboratories. ^ NRC-NRL Research Associate. ^ Present address University of Maryland, College Park, MD. ^1 W.A. Noonan, et al., accepted for publication in Rev. Sci. Instrum.

  7. Measurement of powder bed density in powder bed fusion additive manufacturing processes

    NASA Astrophysics Data System (ADS)

    Jacob, G.; Donmez, A.; Slotwinski, J.; Moylan, S.

    2016-11-01

    Many factors influence the performance of additive manufacturing (AM) processes, resulting in a high degree of variation in process outcomes. Therefore, quantifying these factors and their correlations to process outcomes are important challenges to overcome to enable widespread adoption of emerging AM technologies. In the powder bed fusion AM process, the density of the powder layers in the powder bed is a key influencing factor. This paper introduces a method to determine the powder bed density (PBD) during the powder bed fusion (PBF) process. A complete uncertainty analysis associated with the measurement method was also described. The resulting expanded measurement uncertainty, U PBD (k  =  2), was determined as 0.004 g · cm-3. It was shown that this expanded measurement uncertainty is about three orders of magnitude smaller than the typical powder bed density. This method enables establishing correlations between the changes in PBD and the direction of motion of the powder recoating arm.

  8. A new approach to handle additive and multiplicative uncertainties in the measurement for ? LPV filtering

    NASA Astrophysics Data System (ADS)

    Lacerda, Márcio J.; Tognetti, Eduardo S.; Oliveira, Ricardo C. L. F.; Peres, Pedro L. D.

    2016-04-01

    This paper presents a general framework to cope with full-order ? linear parameter-varying (LPV) filter design subject to inexactly measured parameters. The main novelty is the ability of handling additive and multiplicative uncertainties in the measurements, for both continuous and discrete-time LPV systems, in a unified approach. By conveniently modelling scheduling parameters and uncertainties affecting the measurements, the ? filter design problem can be expressed in terms of robust matrix inequalities that become linear when two scalar parameters are fixed. Therefore, the proposed conditions can be efficiently solved through linear matrix inequality relaxations based on polynomial solutions. Numerical examples are presented to illustrate the improved efficiency of the proposed approach when compared to other methods and, more important, its capability to deal with scenarios where the available strategies in the literature cannot be used.

  9. Rocket borne instrument to measure electric fields inside electrified clouds

    NASA Technical Reports Server (NTRS)

    Ruhnke, L. H. (Inventor)

    1973-01-01

    An apparatus for measuring the electric field in the atmosphere which includes a pair of sensors carried on a rocket for sensing the voltages in the atmosphere being measured is described. One of the sensors is an elongated probe with a fine point which causes a corona current to be produced as it passes through the electric field. An electric circuit is coupled between the probe and the other sensor and includes a high ohm resistor which linearizes the relationship between the corona current and the electric field being measured. A relaxation oscillator and transmitter are provided for generating and transmitting an electric signal having a frequency corresponding to the magnitude of the electric field.

  10. Microwave Imaging and Holographic Diagnostic to Antennas in Cylindrical Near-Field Measurement

    NASA Technical Reports Server (NTRS)

    Hussein, Ziad A.

    1995-01-01

    In this paper, the issues pertaining to microwave imaging and holographic diagnostic to antennas in cylindrical near-field measurements are addressed. The theoretical approach is based on expanding the work in [1] and [2] where a cylindrical wave expansion of the field on a cylindrical near-field surface is given. The sampling probe is modeled by its equivalent aperture current (idealized circular aperture) and incorporated into the near-field to far-field transformation. The method of steepest decent is applied to obtain the far-field. In its implementation, however, one could specify directly the angular spectrum at which the far-field is desired to be calculated without resorting to interpolation. The microwave imaging and holographic diagnostic is based on back projection where a plane wave expansion of the far-field is obtained. This approach necessitates the knowledge of the far-field at exact angular spectrum resulting from application of 2-D FFT. Hence, we were able to construct simply the near-field on a plane not necessarily on the aperture plane of the test antenna but also on planes perpendicular to the aperture plane [3]. And a 3-D high resolution and high precision antenna imaging of the test antenna is obtained from cylindrical near-field simulated measurements. In addition microwave holographic diagnostic of large NASA scatterometer radar antenna obtained from measured near-field on a cylindrical surface will be given if time permits.

  11. Real-World Physics: A Portable MBL for Field Measurements.

    ERIC Educational Resources Information Center

    Albergotti, Clifton

    1994-01-01

    Uses a moderately priced digital multimeter that has output and software compatible with personal computers to make a portable, computer-based data-acquisition system. The system can measure voltage, current, frequency, capacitance, transistor hFE, and temperature. Describes field measures of velocity, acceleration, and temperature as function of…

  12. Field quality measurements of a 2-Tesla transmission line magnet

    SciTech Connect

    Velev, G.V.; Foster, W.; Kashikhin, V.; Mazur, P.; Oleck, A.; Piekarz, H.; Schlabach, P.; Sylvester, C.; Wake, M.; /KEK, Tsukuba

    2005-09-01

    A prototype 2-Tesla superconducting transmission line magnet for future hadron colliders was designed, built and tested at Fermilab. The 1.5 m long, combined-function gradient-dipole magnet has a vertical pole aperture of 20 mm. To measure the magnetic field quality in such a small magnet aperture, a specialized rotating coil of 15.2 mm diameter, 0.69 m long was fabricated. Using this probe, a program of magnetic field quality measurements was successfully performed. Results of the measurements are presented and discussed.

  13. Interpolation And FFT Of Near-Field Antenna Measurements

    NASA Technical Reports Server (NTRS)

    Gatti, Mark S.; Rahmat-Samii, Yahya

    1990-01-01

    Bivariate Lagrange interpolation applied to plane-polar measurement scans. Report discusses recent advances in application of fast-Fourier-transform (FFT) techniques to measurements of near radiation fields of antennas on plane-polar grid. Attention focused mainly on use of such measurements to calculate far radiation fields. Also discussion of use of FFT's in holographic diagnosis of distortions of antenna reflectors. Advantage of scheme, it speeds calculations because it requires fewer data and manipulations of data than other schemes used for this purpose.

  14. Magsat: A satellite for measuring near earth magnetic fields

    NASA Technical Reports Server (NTRS)

    Langel, R. A.; Regan, R. D.; Murphy, J. P.

    1977-01-01

    Magsat, designed for making measurements of the geomagnetic vector field, is evaluated. For accurate vector measurements the attitude of the fluxgate magnetometer will be determined to about 15 arc-seconds. Expected measurement accuracy will be 6 (gamma) in each component and 3 in magnitude. The Magsat data will be applied to solid earth studies including modeling of the Earth's main magnetic field, delineation of regional magnetic anomalies of crustal origin, and interpretation of those anomalies in terms of geologic and geophysical models. An opportunity will be presented to the scientific community to participate in data use investigations.

  15. High-frequency electric field measurement using a toroidal antenna

    DOEpatents

    Lee, Ki Ha

    2002-01-01

    A simple and compact method and apparatus for detecting high frequency electric fields, particularly in the frequency range of 1 MHz to 100 MHz, uses a compact toroidal antenna. For typical geophysical applications the sensor will be used to detect electric fields for a wide range of spectrum starting from about 1 MHz, in particular in the frequency range between 1 to 100 MHz, to detect small objects in the upper few meters of the ground. Time-varying magnetic fields associated with time-varying electric fields induce an emf (voltage) in a toroidal coil. The electric field at the center of (and perpendicular to the plane of) the toroid is shown to be linearly related to this induced voltage. By measuring the voltage across a toroidal coil one can easily and accurately determine the electric field.

  16. Magnetic Field Measurements in Plasmas: Beyond the Traditional Zeeman Spectroscopy

    SciTech Connect

    Doron, R.; Stambulchik, E.; Tessarin, S.; Kroupp, E.; Citrin, J.; Maron, Y.; Tsigutkin, K.

    2009-09-10

    We discuss a new approach to measure magnetic fields in situations where the magnetic-field properties and/or the plasma regime make the traditional Zeeman spectroscopy inapplicable. The approach is particularly useful when the field direction and/or magnitude vary significantly in the region viewed or during the diagnostic system's integration time, and hence no Zeeman splitting can be observed. Similar difficulty may also occur for high-energy-density conditions, where the Zeeman pattern is often completely smeared, regardless of the field distribution, due to the dominant contributions of the Stark and Doppler broadenings to the spectral-line shapes. In the new approach, the magnetic field is inferred from the comparison of the line-shapes of different fine-structure components of the same multiplet, which practically have the same Stark and Doppler broadenings, but different magnetic-field-induced contributions. Limitations of the new method are discussed.

  17. The 2-degree Field Lensing Survey: design and clustering measurements

    NASA Astrophysics Data System (ADS)

    Blake, Chris; Amon, Alexandra; Childress, Michael; Erben, Thomas; Glazebrook, Karl; Harnois-Deraps, Joachim; Heymans, Catherine; Hildebrandt, Hendrik; Hinton, Samuel R.; Janssens, Steven; Johnson, Andrew; Joudaki, Shahab; Klaes, Dominik; Kuijken, Konrad; Lidman, Chris; Marin, Felipe A.; Parkinson, David; Poole, Gregory B.; Wolf, Christian

    2016-11-01

    We present the 2-degree Field Lensing Survey (2dFLenS), a new galaxy redshift survey performed at the Anglo-Australian Telescope. 2dFLenS is the first wide-area spectroscopic survey specifically targeting the area mapped by deep-imaging gravitational lensing fields, in this case the Kilo-Degree Survey. 2dFLenS obtained 70 079 redshifts in the range z < 0.9 over an area of 731 deg2, and is designed to extend the data sets available for testing gravitational physics and promote the development of relevant algorithms for joint imaging and spectroscopic analysis. The redshift sample consists first of 40 531 Luminous Red Galaxies (LRGs), which enable analyses of galaxy-galaxy lensing, redshift-space distortion, and the overlapping source redshift distribution by cross-correlation. An additional 28 269 redshifts form a magnitude-limited (r < 19.5) nearly complete subsample, allowing direct source classification and photometric-redshift calibration. In this paper, we describe the motivation, target selection, spectroscopic observations, and clustering analysis of 2dFLenS. We use power spectrum multipole measurements to fit the redshift-space distortion parameter of the LRG sample in two redshift ranges 0.15 < z < 0.43 and 0.43 < z < 0.7 as β = 0.49 ± 0.15 and β = 0.26 ± 0.09, respectively. These values are consistent with those obtained from LRGs in the Baryon Oscillation Spectroscopic Survey. 2dFLenS data products will be released via our website http://2dflens.swin.edu.au.

  18. Forecasting auroras from regional and global magnetic field measurements

    NASA Astrophysics Data System (ADS)

    Kauristie, Kirsti; Myllys, Minna; Partamies, Noora; Viljanen, Ari; Peitso, Pyry; Juusola, Liisa; Ahmadzai, Shabana; Singh, Vikramjit; Keil, Ralf; Martinez, Unai; Luginin, Alexej; Glover, Alexi; Navarro, Vicente; Raita, Tero

    2016-06-01

    We use the connection between auroral sightings and rapid geomagnetic field variations in a concept for a Regional Auroral Forecast (RAF) service. The service is based on statistical relationships between near-real-time alerts issued by the NOAA Space Weather Prediction Center and magnetic time derivative (dB/dt) values measured by five MIRACLE magnetometer stations located in Finland at auroral and sub-auroral latitudes. Our database contains NOAA alerts and dB/dt observations from the years 2002-2012. These data are used to create a set of conditional probabilities, which tell the service user when the probability of seeing auroras exceeds the average conditions in Fennoscandia during the coming 0-12 h. Favourable conditions for auroral displays are associated with ground magnetic field time derivative values (dB/dt) exceeding certain latitude-dependent threshold values. Our statistical analyses reveal that the probabilities of recording dB/dt exceeding the thresholds stay below 50 % after NOAA alerts on X-ray bursts or on energetic particle flux enhancements. Therefore, those alerts are not very useful for auroral forecasts if we want to keep the number of false alarms low. However, NOAA alerts on global geomagnetic storms (characterized with Kp values > 4) enable probability estimates of > 50 % with lead times of 3-12 h. RAF forecasts thus rely heavily on the well-known fact that bright auroras appear during geomagnetic storms. The additional new piece of information which RAF brings to the previous picture is the knowledge on typical storm durations at different latitudes. For example, the service users south of the Arctic Circle will learn that after a NOAA ALTK06 issuance in night, auroral spotting should be done within 12 h after the alert, while at higher latitudes conditions can remain favourable during the next night.

  19. Auditory evoked field measurement using magneto-impedance sensors

    SciTech Connect

    Wang, K. Tajima, S.; Song, D.; Uchiyama, T.; Hamada, N.; Cai, C.

    2015-05-07

    The magnetic field of the human brain is extremely weak, and it is mostly measured and monitored in the magnetoencephalography method using superconducting quantum interference devices. In this study, in order to measure the weak magnetic field of the brain, we constructed a Magneto-Impedance sensor (MI sensor) system that can cancel out the background noise without any magnetic shield. Based on our previous studies of brain wave measurements, we used two MI sensors in this system for monitoring both cerebral hemispheres. In this study, we recorded and compared the auditory evoked field signals of the subject, including the N100 (or N1) and the P300 (or P3) brain waves. The results suggest that the MI sensor can be applied to brain activity measurement.

  20. Auditory evoked field measurement using magneto-impedance sensors

    NASA Astrophysics Data System (ADS)

    Wang, K.; Tajima, S.; Song, D.; Hamada, N.; Cai, C.; Uchiyama, T.

    2015-05-01

    The magnetic field of the human brain is extremely weak, and it is mostly measured and monitored in the magnetoencephalography method using superconducting quantum interference devices. In this study, in order to measure the weak magnetic field of the brain, we constructed a Magneto-Impedance sensor (MI sensor) system that can cancel out the background noise without any magnetic shield. Based on our previous studies of brain wave measurements, we used two MI sensors in this system for monitoring both cerebral hemispheres. In this study, we recorded and compared the auditory evoked field signals of the subject, including the N100 (or N1) and the P300 (or P3) brain waves. The results suggest that the MI sensor can be applied to brain activity measurement.

  1. Ultrasensitive 3He magnetometer for measurements of high magnetic fields

    NASA Astrophysics Data System (ADS)

    Nikiel, Anna; Blümler, Peter; Heil, Werner; Hehn, Manfred; Karpuk, Sergej; Maul, Andreas; Otten, Ernst; Schreiber, Laura M.; Terekhov, Maxim

    2014-11-01

    We describe a 3He magnetometer capable to measure high magnetic fields ( B> 0.1 T) with a relative accuracy of better than 10-12. Our approach is based on the measurement of the free induction decay of gaseous, nuclear spin polarized 3He following a resonant radio frequency pulse excitation. The measurement sensitivity can be attributed to the long coherent spin precession time T2 ∗ being of order minutes which is achieved for spherical sample cells in the regime of "motional narrowing" where the disturbing influence of field inhomogeneities is strongly suppressed. The 3He gas is spin polarized in situ using a new, non-standard variant of the metastability exchange optical pumping. We show that miniaturization helps to increase T2 ∗ further and that the measurement sensitivity is not significantly affected by temporal field fluctuations of order 10-4.

  2. Linewidth-modulated motional Stark effect measurements of internal field structure in low-field configurations

    SciTech Connect

    Reinecke, E. A.; Fonck, R. J.; Thorson, T. A.

    2001-01-01

    Motional Stark effect measurements of internal field structure in low-field magnetic confinement configurations are considered for both magnitude and direction of the local magnetic field. The amplitude and phase delay of an oscillating spectral linewidth driven by a rotating polarizer provides a means of determining the magnitude and direction of the total field simultaneously while avoiding difficulties of neutral beam energy drift. Photon-noise limit estimates for a diagnostic beam on the low-field PEGASUS toroidal experiment indicate sensitivities of roughly 20 G and 0.2{sup o} for the magnitude and direction angle. These values are sufficient to provide significant constraints on magnetic equilibrium reconstructions.

  3. Solar wind interaction effects on the magnetic fields around Mars: Consequences for interplanetary and crustal field measurements

    NASA Astrophysics Data System (ADS)

    Luhmann, J. G.; Ma, Y.-J.; Brain, D. A.; Ulusen, D.; Lillis, R. J.; Halekas, J. S.; Espley, J. R.

    2015-11-01

    The first unambiguous detections of the crustal remanent magnetic fields of Mars were obtained by Mars Global Surveyor (MGS) during its initial orbits around Mars, which probed altitudes to within ∼110 km of the surface. However, the majority of its measurements were carried out around 400 km altitude, fixed 2 a.m. to 2 p.m. local time, mapping orbit. While the general character and planetary origins of the localized crustal fields were clearly revealed by the mapping survey data, their effects on the solar wind interaction could not be investigated in much detail because of the limited mapping orbit sampling. Previous analyses (Brain et al., 2006) of the field measurements on the dayside nevertheless provided an idea of the extent to which the interaction of the solar wind and planetary fields leads to non-ideal field draping at the mapping altitude. In this study we use numerical simulations of the global solar wind interaction with Mars as an aid to interpreting that observed non-ideal behavior. In addition, motivated by models for different interplanetary field orientations, we investigate the effects of induced and reconnected (planetary and external) fields on the Martian field's properties derived at the MGS mapping orbit altitude. The results suggest that inference of the planetary low order moments is compromised by their influence. In particular, the intrinsic dipole contribution may differ from that in the current models because the induced component is so dominant.

  4. Analyses of magnetic-field peak-exposure summary measures.

    PubMed

    Mezei, Gabor; Bracken, T Dan; Senior, Russell; Kavet, Robert

    2006-11-01

    Two previous epidemiologic studies reported an association between the maximum magnetic field exposure logged during a 24-h measurement period and risk of miscarriage. A hypothesis was put forth which argued that the observed association may be the result of behavioral differences between women with healthy pregnancies (less physically active) and women with miscarriage. We analyzed four existing data sets with power-frequency magnetic-field personal exposure (PE) measurements to investigate the characteristics of peak-exposure measures. We found that the value of the measured maximum magnetic-field exposure varied inversely with the sampling interval between magnetic-field measurements and that maximum values demonstrated less stability over time in repeated measurements, compared to time-weighted average and 95th and 99th -percentile values. We also found that the number of activity categories entered by study subjects could be used to estimate the proportion of subjects with exposure above various threshold values. Exposure metrics based on maximum values exceeding thresholds tend to classify active people into higher exposure categories. These findings are consistent with the hypothesis suggesting that the association between maximum magnetic fields and miscarriage are possibly the result of behavioral differences between women with healthy pregnancies and women who experience miscarriages. Thus, generalization from a given study to more global exposure characterization should be made with particular caution and with due consideration to sampling interval and other characteristics of the measurement protocol potentially influencing the measured maximum. Future epidemiologic studies of peak magnetic field exposure and spontaneous abortion should carefully evaluate the potential confounding effect of the women's activity level during pregnancy.

  5. Magnetic-Field-Response Measurement-Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodward, Stanley E.; Shams, Qamar A.; Fox, Robert L.; Taylor, Bryant D.

    2006-01-01

    A measurement-acquisition system uses magnetic fields to power sensors and to acquire measurements from sensors. The system alleviates many shortcomings of traditional measurement-acquisition systems, which include a finite number of measurement channels, weight penalty associated with wires, use limited to a single type of measurement, wire degradation due to wear or chemical decay, and the logistics needed to add new sensors. Eliminating wiring for acquiring measurements can alleviate potential hazards associated with wires, such as damaged wires becoming ignition sources due to arcing. The sensors are designed as electrically passive inductive-capacitive or passive inductive-capacitive-resistive circuits that produce magnetic-field-responses. One or more electrical parameters (inductance, capacitance, and resistance) of each sensor can be variable and corresponds to a measured physical state of interest. The magnetic-field- response attributes (frequency, amplitude, and bandwidth) of the inductor correspond to the states of physical properties for which each sensor measures. For each sensor, the measurement-acquisition system produces a series of increasing magnetic-field harmonics within a frequency range dedicated to that sensor. For each harmonic, an antenna electrically coupled to an oscillating current (the frequency of which is that of the harmonic) produces an oscillating magnetic field. Faraday induction via the harmonic magnetic fields produces an electromotive force and therefore a current in the sensor. Once electrically active, the sensor produces its own harmonic magnetic field as the inductor stores and releases magnetic energy. The antenna of the measurement- acquisition system is switched from a transmitting to a receiving mode to acquire the magnetic-field response of the sensor. The rectified amplitude of the received response is compared to previous responses to prior transmitted harmonics, to ascertain if the measurement system has detected a

  6. LIF Diagnostic for Measuring Beam-Transport Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Jones, T. G.; Hinshelwood, D. D.; Neri, J. M.; Ottinger, P. F.; Noonan, W. A.

    1997-11-01

    A novel, spatially-resolved diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic technique uses laser-induced fluorescence (LIF) spectroscopy, and can be varied to measure either small or large fields. Small fields, as expected in ballistic transport with solenoidal lens focusing using ~ 1 Torr gas, produce Zeeman shifts, Δ λ_Z, smaller than the transition linewidth, Δ λ. High sensitivity to measure these shifts is achieved by a variation on the Babcock technique.^1 Large fields, as expected in self-pinched transport using 1--100 mTorr gas, produce Δ λZ larger than Δ λ. These Δ λZ will be resolved using an etalon as a narrowband, high-throughput optical filter. Available results from benchtop experiments using calibrated B-fields for both the small- and large-field techniques, and progress in fielding this diagnostic on the Gamble-II accelerator for beam-transport studies will be presented. Work supported by DOE through Sandia National Laboratories. ^ National Research Council Research Associate. ^ Present address University of Maryland, College Park, MD. ^1 W.A. Noonan, et al., Rev. Sci. Instrum. 68, 1032 (1997).

  7. Field Tests of a Laser Raman Measurement System for Aircraft Engine Exhaust Emissions

    DTIC Science & Technology

    1974-10-01

    practical one. The advantages of optical exhaust gas measurements versus probing systems has been demonstrated. It now remains to solve the remaining...Raman system NOVA digital data processor has the capability to service such additional measurements. If velocity information is desired a study should be...AD/A-003 648 FIELD TESTS OF A LASER RAMAN MEASURE- MENT SYSTEM FOR AIRCRAFT ENGINE EXHAUST EMISSIONS Donald A. Leunard Avoo Everett Researoh

  8. Boundedness of completely additive measures with application to 2-local triple derivations

    NASA Astrophysics Data System (ADS)

    Hamhalter, Jan; Kudaybergenov, Karimbergen; Peralta, Antonio M.; Russo, Bernard

    2016-02-01

    We prove a Jordan version of Dorofeev's boundedness theorem for completely additive measures and use it to show that every (not necessarily linear nor continuous) 2-local triple derivation on a continuous JBW∗-triple is a triple derivation. 2-local triple derivations are well understood on von Neumann algebras. JBW*-triples, which are properly defined in Section I, are intimately related to infinite dimensional holomorphy and include von Neumann algebras as special cases. In particular, continuous JBW∗-triples can be realized as subspaces of continuous von Neumann algebras which are stable for the triple product xy∗z + zy∗x and closed in the weak operator topology.

  9. A multiple additive regression tree analysis of three exposure measures during Hurricane Katrina.

    PubMed

    Curtis, Andrew; Li, Bin; Marx, Brian D; Mills, Jacqueline W; Pine, John

    2011-01-01

    This paper analyses structural and personal exposure to Hurricane Katrina. Structural exposure is measured by flood height and building damage; personal exposure is measured by the locations of 911 calls made during the response. Using these variables, this paper characterises the geography of exposure and also demonstrates the utility of a robust analytical approach in understanding health-related challenges to disadvantaged populations during recovery. Analysis is conducted using a contemporary statistical approach, a multiple additive regression tree (MART), which displays considerable improvement over traditional regression analysis. By using MART, the percentage of improvement in R-squares over standard multiple linear regression ranges from about 62 to more than 100 per cent. The most revealing finding is the modelled verification that African Americans experienced disproportionate exposure in both structural and personal contexts. Given the impact of exposure to health outcomes, this finding has implications for understanding the long-term health challenges facing this population.

  10. AUV Turbulence Measurements in the LOCO Field Experiments

    DTIC Science & Technology

    2009-01-01

    Chlorophyll Fluormeter. In addition, the vehicle contains a variety of “hotel” sensors which measure pitch , roll , yaw, and other internal dynamical...Inc., containing the Rockland Microstructure Measurement System (RMMS), an upward and downward looking 1.2 MHz ADCP , a FASTCAT Seabird CTD, and a WET

  11. Three-dimensional photogrammetric measurement of magnetic field lines in the WEGA stellarator.

    PubMed

    Drewelow, Peter; Bräuer, Torsten; Otte, Matthias; Wagner, Friedrich; Werner, Andreas

    2009-12-01

    The magnetic confinement of plasmas in fusion experiments can significantly degrade due to perturbations of the magnetic field. A precise analysis of the magnetic field in a stellarator-type experiment utilizes electrons as test particles following the magnetic field line. The usual fluorescent detector for this electron beam limits the provided information to two-dimensional cut views at certain toroidal positions. However, the technique described in this article allows measuring the three-dimensional structure of the magnetic field by means of close-range photogrammetry. After testing and optimizing the main diagnostic components, measurements of the magnetic field lines were accomplished with a spatial resolution of 5 mm. The results agree with numeric calculations, qualifying this technique as an additional tool to investigate magnetic field configurations in a stellarator. For a possible future application, ways are indicated on how to reduce experimental error sources.

  12. Electric field measurements during the Condor critical velocity experiment

    NASA Technical Reports Server (NTRS)

    Kelley, M. C.; Pfaff, R. F.; Haerendel, G.

    1986-01-01

    The instrumentation of the Condor critical velocity Ba experiment (Wescott et al., 1986) for the measurements of the energetic particles and the electric field associated with a Ba explosion is described. The Ba explosion created a complex electric field pulse detected in situ by a single-axis double electric-field probe on a separate spacecraft. The measurements provide evidence of several important links in the critical-velocity chain, and are consistent with two hypotheses. The first hypothesis involves the creation of large polarization electric field due to charge separation; the second hypothesis implies a polarization of the beam by currents flowing across it. The chain of physical processes inferred from the observations is in agreement with most theories for the Alfven process.

  13. Radiological Disaster Simulators for Field and Aerial Measurements

    SciTech Connect

    H. W. Clark, Jr

    2002-11-01

    Simulators have been developed to dramatically improve the fidelity of play for field monitors and aircraft participating in radiological disaster drills and exercises. Simulated radiological measurements for the current Global Positioning System (GPS) location are derived from realistic models of radiological consequences for accidents and malicious acts. The aerial version outputs analog pulses corresponding to the signal that would be produced by various NaI (Tl) detectors at that location. The field monitor version reports the reading for any make/model of survey instrument selected. Position simulation modes are included in the aerial and field versions. The aerial version can generate a flight path based on input parameters or import an externally generated sequence of latitude and longitude coordinates. The field version utilizes a map-based point and click/drag interface to generate individual or a sequence of evenly spaced instrument measurements.

  14. Capabilities and limitations of atmospheric transmission field measurement systems

    NASA Astrophysics Data System (ADS)

    Zweibaum, F. M.; Lucia, L. V.; Lamontagne, J. J.; Kozlowski, A. T.

    1981-01-01

    The major subject of the paper is advancing atmospheric transmission field measurement systems in response to new requirements. From the viewpoint of a complete field system installation, attention is given to the nature of the measurement and the capabilities and limitations in sensitivity, stability, and the time required for individual measurements. From the same system viewpoint calibration is reviewed with regard to concept, techniques, uncertainties and assumptions. Examples are given of system advances and these include making real-time measurements with automatic high-speed scanning, high sensitivity, wide spectral range and remote control. Special measurement conditions that are described include those encountered on the battlefield, in fog and precipitation, and in the presence of countermeasures.

  15. An algorithm to estimate unsteady and quasi-steady pressure fields from velocity field measurements.

    PubMed

    Dabiri, John O; Bose, Sanjeeb; Gemmell, Brad J; Colin, Sean P; Costello, John H

    2014-02-01

    We describe and characterize a method for estimating the pressure field corresponding to velocity field measurements such as those obtained by using particle image velocimetry. The pressure gradient is estimated from a time series of velocity fields for unsteady calculations or from a single velocity field for quasi-steady calculations. The corresponding pressure field is determined based on median polling of several integration paths through the pressure gradient field in order to reduce the effect of measurement errors that accumulate along individual integration paths. Integration paths are restricted to the nodes of the measured velocity field, thereby eliminating the need for measurement interpolation during this step and significantly reducing the computational cost of the algorithm relative to previous approaches. The method is validated by using numerically simulated flow past a stationary, two-dimensional bluff body and a computational model of a three-dimensional, self-propelled anguilliform swimmer to study the effects of spatial and temporal resolution, domain size, signal-to-noise ratio and out-of-plane effects. Particle image velocimetry measurements of a freely swimming jellyfish medusa and a freely swimming lamprey are analyzed using the method to demonstrate the efficacy of the approach when applied to empirical data.

  16. Extension of laboratory-measured soil spectra to field conditions

    NASA Technical Reports Server (NTRS)

    Stoner, E. R.; Baumgardner, M. F.; Weismiller, R. A.; Biehl, L. L.; Robinson, B. F.

    1982-01-01

    Spectral responses of two glaciated soils, Chalmers silty clay loam and Fincastle silt loam, formed under prairie grass and forest vegetation, respectively, were measured in the laboratory under controlled moisture equilibria using an Exotech Model 20C spectroradiometer to obtain spectral data in the laboratory under artificial illumination. The same spectroradiometer was used outdoors under solar illumination to obtain spectral response from dry and moistened field plots with and without corn residue cover, representing the two different soils. Results indicate that laboratory-measured spectra of moist soil are directly proportional to the spectral response of that same field-measured moist bare soil over the 0.52 micrometer to 1.75 micrometer wavelength range. The magnitudes of difference in spectral response between identically treated Chalmers and Fincastle soils are greatest in the 0.6 micrometers to 0.8 micrometer transition region between the visible and near infrared, regardless of field condition or laboratory preparation studied.

  17. Estimating of pulsed electric fields using optical measurements.

    SciTech Connect

    Flanagan, Timothy McGuire; Chantler, Gary.

    2013-09-01

    We performed optical electric field measurements ion nanosecond time scales using the electrooptic crystal beta barium borate (BBO). Tests were based on a preliminary bench top design intended to be a proofofprinciple stepping stone towards a modulardesign optical Efield diagnostic that has no metal in the interrogated environment. The long term goal is to field a modular version of the diagnostic in experiments on large scale xray source facilities, or similarly harsh environments.

  18. Numerical simulation in alternating current field measurement inducer design

    NASA Astrophysics Data System (ADS)

    Zhou, Zhixiong; Zheng, Wenpei

    2017-02-01

    The present work develops a numerical simulation model to evaluate the magnetic field perturbation of a twin coil alternating current field measurement (ACFM) inducer passing above a surface-breaking crack for the purpose of enhanced crack detection. Model predictions show good agreement with experimental data, verifying the accuracy of the model. The model includes the influence of various parameters, such as core dimensions and core positions on the perturbed magnetic field above a crack. Optimized design parameters for a twin coil inducer are given according to the analysis results, which provide for a greatly improved detection effect.

  19. The FORS1 catalogue of stellar magnetic field measurements

    NASA Astrophysics Data System (ADS)

    Bagnulo, S.; Fossati, L.; Landstreet, J. D.; Izzo, C.

    2015-11-01

    Context. The FORS1 instrument on the ESO Very Large Telescope was used to obtain low-resolution circular polarised spectra of nearly a thousand different stars, with the aim of measuring their mean longitudinal magnetic fields. Magnetic fields were measured by different authors, and using different methods and software tools. Aims: A catalogue of FORS1 magnetic measurements would provide a valuable resource with which to better understand the strengths and limitations of this instrument and of similar low-dispersion, Cassegrain spectropolarimeters. However, FORS1 data reduction has been carried out by a number of different groups using a variety of reduction and analysis techniques. Our understanding of the instrument and our data reduction techniques have both improved over time. A full re-analysis of FORS1 archive data using a consistent and fully documented algorithm would optimise the accuracy and usefulness of a catalogue of field measurements. Methods: Based on the ESO FORS pipeline, we have developed a semi-automatic procedure for magnetic field determinations, which includes self-consistent checks for field detection reliability. We have applied our procedure to the full content of circular spectropolarimetric measurements of the FORS1 archive. Results: We have produced a catalogue of spectro-polarimetric observations and magnetic field measurements for ~1400 observations of ~850 different objects. The spectral type of each object has been approximately classified. We have also been able to test different methods for data reduction is a systematic way. The resulting catalogue has been used to produce an estimator for an upper limit to the uncertainty in a field strength measurement of an early type star as a function of the signal-to-noise ratio of the observation. Conclusions: While FORS1 is not necessarily an optimal instrument for the discovery of weak magnetic fields, it is very useful for the systematic study of larger fields, such as those found in Ap

  20. Precise measurement of magnetization characteristics in high pulsed field

    NASA Astrophysics Data System (ADS)

    Nakahata, Y.; Borkowski, B.; Shimoji, H.; Yamada, K.; Todaka, T.; Enokizono, M.

    2012-04-01

    Permanent magnets, especially Nd-Fe-B magnets, are very important engineering elements that are widely used in many applications. The detailed design of electrical and electronic equipment using permanent magnets requires the precise measurement of magnetization characteristics. High pulsed magnetic fields can be used to measure the magnetization characteristics of permanent magnets in the easy and hard magnetization directions. Errors influencing the measurements stem from the relationship between the tested material, pick-up sensor configuration, and excitation coil. We present an analysis of the effect of the sensor construction on the accuracy of the measurements of the material's magnetic properties. We investigated the coaxial and series types sensor configurations.

  1. Direct field measurement of the dynamic amplification in a bridge

    NASA Astrophysics Data System (ADS)

    Carey, Ciarán; OBrien, Eugene J.; Malekjafarian, Abdollah; Lydon, Myra; Taylor, Su

    2017-02-01

    In this paper, the level of dynamics, as described by the Assessment Dynamic Ratio (ADR), is measured directly through a field test on a bridge in the United Kingdom. The bridge was instrumented using fiber optic strain sensors and piezo-polymer weigh-in-motion sensors were installed in the pavement on the approach road. Field measurements of static and static-plus-dynamic strains were taken over 45 days. The results show that, while dynamic amplification is large for many loading events, these tend not to be the critical events. ADR, the allowance that should be made for dynamics in an assessment of safety, is small.

  2. Near field optical probe for critical dimension measurements

    DOEpatents

    Stallard, Brian R.; Kaushik, Sumanth

    1999-01-01

    A resonant planar optical waveguide probe for measuring critical dimensions on an object in the range of 100 nm and below. The optical waveguide includes a central resonant cavity flanked by Bragg reflector layers with input and output means at either end. Light is supplied by a narrow bandwidth laser source. Light resonating in the cavity creates an evanescent electrical field. The object with the structures to be measured is translated past the resonant cavity. The refractive index contrasts presented by the structures perturb the field and cause variations in the intensity of the light in the cavity. The topography of the structures is determined from these variations.

  3. Near field optical probe for critical dimension measurements

    DOEpatents

    Stallard, B.R.; Kaushik, S.

    1999-05-18

    A resonant planar optical waveguide probe for measuring critical dimensions on an object in the range of 100 nm and below is disclosed. The optical waveguide includes a central resonant cavity flanked by Bragg reflector layers with input and output means at either end. Light is supplied by a narrow bandwidth laser source. Light resonating in the cavity creates an evanescent electrical field. The object with the structures to be measured is translated past the resonant cavity. The refractive index contrasts presented by the structures perturb the field and cause variations in the intensity of the light in the cavity. The topography of the structures is determined from these variations. 8 figs.

  4. Acceptance test report: Field test of mixer pump for 241-AN-107 caustic addition project

    SciTech Connect

    Leshikar, G.A.

    1997-05-16

    The field acceptance test of a 75 HP mixer pump (Hazleton serial number N-20801) installed in Tank 241-AN-107 was conducted from October 1995 thru February 1996. The objectives defined in the acceptance test were successfully met, with two exceptions recorded. The acceptance test encompassed field verification of mixer pump turntable rotation set-up and operation, verification that the pump instrumentation functions within established limits, facilitation of baseline data collection from the mixer pump mounted ultrasonic instrumentation, verification of mixer pump water flush system operation and validation of a procedure for its operation, and several brief test runs (bump) of the mixer pump.

  5. Hy-wire and fast electric field change measurements near an isolated thunderstorm, appendix C

    NASA Technical Reports Server (NTRS)

    Holzworth, R. H.; Levine, D. M.

    1983-01-01

    Electric field measurements near an isolated thunderstorm at 6.4 km distance are presented from both a tethered balloon experiment called Hy-wire and also from ground based fast and slow electric field change systems. Simultaneous measurements were made of the electric fields during several lightning flashes at the beginning of the storm which the data clearly indicate were cloud-to-ground flashes. In addition to providing a comparison between the Hy-wire technique for measuring electric fields and more traditional methods, these data are interesting because the lightning flashes occurred prior to changes in the dc electric field, although Hy-wire measured changes in the dc field of up to 750 V/m in the direction opposite to the fair weather field a short time later. Also, the dc electric field was observed to decay back to its preflash value after each flash. The data suggest that Hy-wire was at the field reversal distance from this storm and suggest the charge realignment was taking place in the cloud with a time constant on the order of 20 seconds.

  6. Additional Measurements and Analyses of H217O and H218O

    NASA Astrophysics Data System (ADS)

    Pearson, John; Yu, Shanshan; Walters, Adam; Daly, Adam M.

    2015-06-01

    Historically the analysis of the spectrum of water has been a balance between the quality of the data set and the applicability of the Hamiltonian to a highly non-rigid molecule. Recently, a number of different non-rigid analysis approaches have successfully been applied to 16O water resulting in a self-consistent set of transitions and energy levels to high J which allowed the spectrum to be modeled to experimental precision. The data set for 17O and 18O water was previously reviewed and many of the problematic measurements identified, but Hamiltonian modeling of the remaining data resulted in significantly poorer quality fits than that for the 16O parent. As a result, we have made additional microwave measurements and modeled the existing 17O and 18O data sets with an Euler series model. This effort has illuminated a number of additional problematic measurements in the previous data sets and has resulted in analyses of 17O and 18O water that are of similar quality to the 16O analysis. We report the new lines, the analyses and make recommendations on the quality of the experimental data sets. SS. Yu, J.C. Pearson, B.J. Drouin et al. J. Mol. Spectrosc. 279,~16-25 (2012) J. Tennyson, P.F. Bernath, L.R. Brown et al. J. Quant. Spectrosc. Rad. Trans. 117, 29-58 (2013) J. Tennyson, P.F. Bernath, L.R. Brown et al. J. Quant. Spectrosc. Rad. Trans. 110, 573-596 (2009) H.M. Pickett, J.C. Pearson, C.E. Miller J. Mol. Spectrosc. 233, 174-179 (2005)

  7. Government regulation and public opposition create high additional costs for field trials with GM crops in Switzerland.

    PubMed

    Bernauer, Thomas; Tribaldos, Theresa; Luginbühl, Carolin; Winzeler, Michael

    2011-12-01

    Field trials with GM crops are not only plant science experiments. They are also social experiments concerning the implications of government imposed regulatory constraints and public opposition for scientific activity. We assess these implications by estimating additional costs due to government regulation and public opposition in a recent set of field trials in Switzerland. We find that for every Euro spent on research, an additional 78 cents were spent on security, an additional 31 cents on biosafety, and an additional 17 cents on government regulatory supervision. Hence the total additional spending due to government regulation and public opposition was around 1.26 Euros for every Euro spent on the research per se. These estimates are conservative; they do not include additional costs that are hard to monetize (e.g. stakeholder information and dialogue activities, involvement of various government agencies). We conclude that further field experiments with GM crops in Switzerland are unlikely unless protected sites are set up to reduce these additional costs.

  8. Peculiarities of electric field measurements in magnetotelluric sounding.

    NASA Astrophysics Data System (ADS)

    Pronenko, Vira; Prystai, Andrii; Korepanov, Valery

    2014-05-01

    The study of deep structure of the Earth is of great interest for both applied (e. g., mineral exploration) and scientific research. For this the electromagnetic (EM) studies which enable to construct the distribution of electrical conductivity in the Earth's crust are of great use. The most common method of EM exploration is magnetotelluric sounding (MTS). This method is a passive method of research, which uses a wide range of natural geomagnetic variations as a powerful source of electromagnetic induction in the Earth. MTS technique includes first the measurements of variations of natural electric and magnetic fields in orthogonal directions at the surface of the Earth, and then the conductivity structure of the Earth's crust is determined by the obtained data processing and as a result the geoelectric cross-section for the depths of several tens of meters to several hundred kilometres is constructed. Like other methods, MTS has its limitations. The mmeasurements of electric field are the most complicated metrological process mostly limiting the accuracy of magnetotelluric prospecting. We believe that the increase of the accuracy of the electric field measurement can significantly improve the quality of magnetotelluric data. It is known that the measurement of the electric field is the biggest problem during the MTS. First of all, this is due to quite small values of the measured variations of the electric field compared to the so-called contact potential arising at the interface of the contact of the electrode with the environment. The shortcomings of a construction of different kind of non-polarized electrode were studied and in the result a new improved design of non-polarized LEMI-701 electrode based on the combination of Cu - CuSO4 is proposed. A number of specific requirements should be taken into account at electric field meter design because it must measure signals with periods ranging from fractions of seconds to about 100.000 second with minimal error

  9. Fast near-field far-field transformation for phaseless and irregular antenna measurement data

    NASA Astrophysics Data System (ADS)

    Schnattinger, G.; Lopez, C.; Kılıç, E.; Eibert, T. F.

    2014-11-01

    The characterization of antenna radiation patterns by transformed near-field measurements requires accurate amplitude and phase data. This represents a problem since expensive measurement equipment is required, especially at millimeter and submillimeter wavelengths (Isernia et al., 1996). Amplitude-only antenna field measurements are theoretically sufficient for the unique determination of antenna far-fields. Therefore, phaseless techniques are of special interest. However, the required field transformations are extremely challenging, since they are nonlinear and strongly ill-posed. In this work, the amplitude-only or phaseless near-field far-field transformation problem is formulated as a nonlinear optimization problem. The linear radiation operator within the nonlinear formulation is evaluated using the fast irregular antenna field transformation algorithm (FIAFTA). A hybrid solution procedure is described which combines a genetic algorithm with an iterative conjugate gradient (CG) search method. Numerical results prove the efficiency and flexibility of the formulation and it is shown that the algorithm remains stable when the noise level in the measurements is moderate. Nevertheless, regularization techniques might be beneficial to further improve the robustness of the algorithm.

  10. Tip vortex core pressure estimates derived from velocity field measurements

    NASA Astrophysics Data System (ADS)

    Sinding, Kyle; Krane, Michael

    2016-11-01

    We present estimates of tip vortex core pressure derived from velocity field measurements of a high Reynolds number flow over a lifting surface. Tip vortex cavitation decreases propulsor efficiency and contributes to both unwanted noise and surface damage. Coordinated load cell, pressure, and velocity measurements were performed in the 12-inch tunnel at the Applied Research Laboratory at Penn State University, over a range of angles of attack and flow speeds. Stereo PIV imaging planes were oriented normal to the tunnel axis. Pressure estimates in each measurement plane were estimated from the velocity field. Visual cavitation calls were performed over the same range of conditions as the optical velocity measurements, by varying the tunnel pressure until tip vortex cavitation was observed to initiate. The pressure differences between the tip vortex and the tunnel ambient pressure obtained with these two methods were then compared.

  11. Analyzing Extragalactic Magnetic Fields Using Faraday Rotation Measure Synthesis

    NASA Astrophysics Data System (ADS)

    Pare, Dylan; Wang, Q. Daniel; Kamieneski, Patrick; Sullivan, Kendall

    2017-01-01

    Extragalactic magnetic fields are a poorly understood element of galaxies that are likely to play an important role in galaxy formation and evolution. Until recently, however, there was no way to observe these fields to a high level of detail, making it difficult to map the spatial distribution of these fields to any high degree of accuracy. Fortunately, a new technique known as Faraday Rotation Measure Synthesis allows for a more precise analysis of galactic magnetism. This technique uses the observed Faraday rotation of polarized emission from background sources to map the magnetic field of a foreground galaxy. This Faraday rotation occurs when the polarized emission encounters ionized, magnetized gas within the galaxy, causing the emission to be rotated by an amount proportional the magnetic field subjected to the ionized gas. Working as part of CHANG-ES (Continuum HAlos in Nearby Galaxies - an EVLA Survey), we have applied this technique in order to learn about the distribution of magnetic fields in the disks and halos of edge-on spiral galaxies. We will present maps of the galactic magnetic fields of CHANG-ES galaxies using this technique, indicating the potential of this technique in successfully mapping these distant fields.

  12. Longitudinal and transversal bioimpedance measurements in addition to diagnosis of heart failure

    NASA Astrophysics Data System (ADS)

    Ribas, N.; Nescolarde, L.; Domingo, M.; Gastelurrutia, P.; Bayés-Genis, A.; Rosell-Ferrer, J.

    2010-04-01

    Heart Failure (HF) is a clinical syndrome characterised by signs of systemic and pulmonary fluid retention, shortness of breath and/or fatigue. There is a lack of reliable indicators of disease state. Benefits and applicability of non-invasive bioimpedance measurement in the hydration state of soft tissues have been validated, fundamentally, in dialysis patients. Four impedance configurations (2 longitudinal and 2 transversal) were analyzed in 48 HF patients (M=28, F=20) classified according to a clinical disease severity score (CDSS) derived from the Framingham criteria: CDSS<=2 (G1: M = 23, F = 14) and CDSS>2 (G2: M = 5, F = 6). The aim of this study is to analyze longitudinal and transversal bioimpedance measurement at 50 kHz, in addition to clinical diagnosis parameters of heart failure, including: clinical disease severity score (CDSS) and a biomarker concentrations (NT-proBNP). The Kolmogorov-Smirnov test was used for the normality test of all variables. The CDSS, NTproBNP and impedance parameters between groups (G1 and G2) were compared by mean of Mann Withney U-test. The statistical significance was considered with P < 0.05. Whole-body impedance measured was analyzed using RXc graph.

  13. Time-Resolved In Situ Measurements During Rapid Alloy Solidification: Experimental Insight for Additive Manufacturing

    DOE PAGES

    McKeown, Joseph T.; Zweiacker, Kai; Liu, Can; ...

    2016-01-27

    In research and industrial environments, additive manufacturing (AM) of metals and alloys is becoming a pervasive technology, though significant challenges remain before widespread implementation of AM can be realized. In situ investigations of rapid alloy solidification with high spatial and temporal resolutions can provide unique experimental insight into microstructure evolution and kinetics that are relevant for AM processing. Hypoeutectic thin-film Al–Cu and Al–Si alloys were investigated using dynamic transmission electron microscopy to monitor pulsed-laser-induced rapid solidification across microsecond timescales. Solid–liquid interface velocities measured from time-resolved images revealed accelerating solidification fronts in both alloys. We observed microstructure evolution, solidification product, andmore » presence of a morphological instability at the solid–liquid interface in the Al–4 at.%Cu alloy are related to the measured interface velocities and small differences in composition that affect the thermophysical properties of the alloys. These time-resolved in situ measurements can inform and validate predictive modeling efforts for AM.« less

  14. Time-Resolved In Situ Measurements During Rapid Alloy Solidification: Experimental Insight for Additive Manufacturing

    SciTech Connect

    McKeown, Joseph T.; Zweiacker, Kai; Liu, Can; Coughlin, Daniel R.; Clarke, Amy J.; Baldwin, J. Kevin; Gibbs, John W.; Roehling, John D.; Imhoff, Seth D.; Gibbs, Paul J.; Tourret, Damien; Wiezorek, Jörg M. K.; Campbell, Geoffrey H.

    2016-01-27

    In research and industrial environments, additive manufacturing (AM) of metals and alloys is becoming a pervasive technology, though significant challenges remain before widespread implementation of AM can be realized. In situ investigations of rapid alloy solidification with high spatial and temporal resolutions can provide unique experimental insight into microstructure evolution and kinetics that are relevant for AM processing. Hypoeutectic thin-film Al–Cu and Al–Si alloys were investigated using dynamic transmission electron microscopy to monitor pulsed-laser-induced rapid solidification across microsecond timescales. Solid–liquid interface velocities measured from time-resolved images revealed accelerating solidification fronts in both alloys. We observed microstructure evolution, solidification product, and presence of a morphological instability at the solid–liquid interface in the Al–4 at.%Cu alloy are related to the measured interface velocities and small differences in composition that affect the thermophysical properties of the alloys. These time-resolved in situ measurements can inform and validate predictive modeling efforts for AM.

  15. MESA: a new configuration for measuring electromagnetic field fluctuations.

    PubMed

    Harte, T M; Black, D L; Hollinshead, M T

    1999-11-01

    This paper describes how the multi-energy sensor array has been refitted to meet the needs of measuring geomagnetic and other types of electromagnetic phenomena in an environment. This portable laptop computer system was designed to measure the interaction of multiple frequencies with the psychological and physiological processes that underlie human exposure to electromagnetic fields across the spectra. New sensors and analytical software have been implemented in the new configuration.

  16. Work function measurements by the field emission retarding potential method.

    NASA Technical Reports Server (NTRS)

    Strayer, R. W.; Mackie, W.; Swanson, L. W.

    1973-01-01

    Description of the theoretical foundation of the field electron retarding potential method, and review of its experimental application to the measurement of single crystal face work functions. The results obtained from several substrates are discussed. An interesting and useful fallout from the experimental approach described is the ability to accurately measure the elastic and inelastic reflection coefficient for impinging electrons to near zero-volt energy.

  17. MEASUREMENTS OF STELLAR MAGNETIC FIELDS USING AUTOCORRELATION OF SPECTRA

    SciTech Connect

    Borra, E. F.; Deschatelets, D.

    2015-11-15

    We present a novel technique that uses the autocorrelation of the spectrum of a star to measure the line broadening caused by the modulus of its average surface magnetic field. The advantage of the autocorrelation comes from the fact that it can detect very small spectral line broadening effects because it averages over many spectral lines and therefore gives an average with a very high signal-to-noise ratio. We validate the technique with the spectra of known magnetic stars and obtain autocorrelation curves that are in full agreement with published magnetic curves obtained with Zeeman splitting. The autocorrelation also gives less noisy curves so that it can be used to obtain very accurate curves. We degrade the resolution of the spectra of these magnetic stars to lower spectral resolutions where the Zeeman splitting is undetectable. At these resolutions, the autocorrelation still gives good quality curves, thereby showing that it can be used to measure magnetic fields in spectra where the Zeeman splitting is significantly smaller than the width of the spectral line. This would therefore allow observing magnetic fields in very faint Ap stars with low-resolution spectrographs, thereby greatly increasing the number of known magnetic stars. It also demonstrates that the autocorrelation can measure magnetic fields in rapidly rotating stars as well as weak magnetic fields that give a Zeeman splitting smaller than the intrinsic width of the spectral lines. Finally, it shows that the autocorrelation can be used to find unknown magnetic stars in low-resolution spectroscopic surveys.

  18. Measurements of magnetic field stability in inhomogeneous magnetic fields at low temperature

    NASA Astrophysics Data System (ADS)

    Hugon, Cedric; Jacquinot, Jacques-Francois; Sakellariou, Dimitris

    2010-01-01

    We present an original method for field stability measurements in a bath of liquid helium. This method is used to validate the power supply of a superconductive magnet operating in driven mode. The experiment consists in the measurement of the NMR signal of a sample of liquid 3He, placed inside the field of a test magnet driven by a power supply. The homogeneity of the magnet is a strongly limiting factor for measurements but through the use of an inductively coupled microcoil and careful signal processing, a precision of 5.5 ppm was achieved.

  19. Flow Field Measurement of Mixing Driven by Buoyancy

    NASA Technical Reports Server (NTRS)

    Batur, C.; Zhong, H.

    2003-01-01

    Mixing driven by buoyancy-induced flows inside a cavity consists of stretching and folding of an interface. Measurement of the flow field using particle imaging velocimetry shows that during stretching the flow field has a single elliptic point, thus dominated by a single vortex. However, global bifurcation that results in folding introduces a hyperbolic point whereby the flow field degenerates to multiple vortex interactions. The short-lived coherent structure observed during mixing which results in the Rayleigh- Taylor morphology is attributed to vortex interactions. The mixing characteristics of non-homogeneous fluids driven by buoyancy are important towards understanding transport phenomenon in a microgravity environment. Mixing consists of stretching and folding of an interface due to a flow field whose intensity depends on the body force. For miscible liquids, the characteristic of the flow field determines whether mass transport is governed by diffusion or bulk stirring which induces mixing. For technologically important processes, transport of mass is governed by the coupling of the body force to scalar gradients such as concentration and or temperature' 2 3 . In order to lend insight into these classes of problems we consider a model experimental system to study mixing driven by buoyancy-induced flows. The characteristics of mixing is addressed from detail measurements of the flow field using particle imaging velocimetry (PIV), and its corresponding interface dynamics using image processing techniques.

  20. Additional field verification of convective scaling for the lateral dispersion parameter

    SciTech Connect

    Sakiyama, S.K.; Davis, P.A.

    1988-07-01

    The results of a series of diffusion trials over the heterogeneous surface of the Canadian Precambrian Shield provide additional support for the convective scaling of the lateral dispersion parameter. The data indicate that under convective conditions, the lateral dispersion parameter can be scaled with the convective velocity scale and the mixing depth. 10 references.

  1. Calculation of multicenter electric field gradient integrals over Slater-type orbitals using unsymmetrical one-range addition theorems.

    PubMed

    Guseinov, Israfil I; Görgün, Nurşen Seçkin

    2011-06-01

    The electric field induced within a molecule by its electrons determines a whole series of important physical properties of the molecule. In particular, the values of the gradient of this field at the nuclei determine the interaction of their quadrupole moments with the electrons. Using unsymmetrical one-range addition theorems introduced by one of the authors, the sets of series expansion relations for multicenter electric field gradient integrals over Slater-type orbitals in terms of multicenter charge density expansion coefficients and two-center basic integrals are presented. The convergence of the series is tested by calculating concrete cases for different values of quantum numbers, parameters and locations of orbitals.

  2. Low-altitude magnetic field measurements by MESSENGER reveal Mercury’s ancient crustal field

    NASA Astrophysics Data System (ADS)

    Johnson, Catherine L.; Phillips, Roger J.; Purucker, Michael E.; Anderson, Brian J.; Byrne, Paul K.; Denevi, Brett W.; Feinberg, Joshua M.; Hauck, Steven A.; Head, James W.; Korth, Haje; James, Peter B.; Mazarico, Erwan; Neumann, Gregory A.; Philpott, Lydia C.; Siegler, Matthew A.; Tsyganenko, Nikolai A.; Solomon, Sean C.

    2015-05-01

    Magnetized rocks can record the history of the magnetic field of a planet, a key constraint for understanding its evolution. From orbital vector magnetic field measurements of Mercury taken by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft at altitudes below 150 kilometers, we have detected remanent magnetization in Mercury’s crust. We infer a lower bound on the average age of magnetization of 3.7 to 3.9 billion years. Our findings indicate that a global magnetic field driven by dynamo processes in the fluid outer core operated early in Mercury’s history. Ancient field strengths that range from those similar to Mercury’s present dipole field to Earth-like values are consistent with the magnetic field observations and with the low iron content of Mercury’s crust inferred from MESSENGER elemental composition data.

  3. Planetary science. Low-altitude magnetic field measurements by MESSENGER reveal Mercury's ancient crustal field.

    PubMed

    Johnson, Catherine L; Phillips, Roger J; Purucker, Michael E; Anderson, Brian J; Byrne, Paul K; Denevi, Brett W; Feinberg, Joshua M; Hauck, Steven A; Head, James W; Korth, Haje; James, Peter B; Mazarico, Erwan; Neumann, Gregory A; Philpott, Lydia C; Siegler, Matthew A; Tsyganenko, Nikolai A; Solomon, Sean C

    2015-05-22

    Magnetized rocks can record the history of the magnetic field of a planet, a key constraint for understanding its evolution. From orbital vector magnetic field measurements of Mercury taken by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft at altitudes below 150 kilometers, we have detected remanent magnetization in Mercury's crust. We infer a lower bound on the average age of magnetization of 3.7 to 3.9 billion years. Our findings indicate that a global magnetic field driven by dynamo processes in the fluid outer core operated early in Mercury's history. Ancient field strengths that range from those similar to Mercury's present dipole field to Earth-like values are consistent with the magnetic field observations and with the low iron content of Mercury's crust inferred from MESSENGER elemental composition data.

  4. Studies on Partially Coherent Fields and Coherence Measurement Methods

    NASA Astrophysics Data System (ADS)

    Cho, Seongkeun

    The concept of coherence in optics means how closely an optical field oscillates in unison at the same position in different time (temporal coherence) or at different positions at the same time (spatial coherence). Since all optical fields oscillate very rapidly with random fluctuations, coherence theory has been developed to describe the state of coherence of those optical fields through the usage of time-averaged correlation functions. This thesis reviews and applies coherence theory for an accurate and improved modeling in field-propagation and coherence measurement for partially coherent fields. The first half of this thesis discusses the study of phase-space distributions and phase-space tomography. Phase-space distributions such as the Wigner and the ambiguity functions can be used as simple mathematical tools for describing the propagation of an optical field for any state of coherence as those functions incorporate wave effects with the simplicity of ray optics. However, the Wigner and the ambiguity functions require a paraxial condition for the field description. To overcome this limitation, the nonparaxial extensions of the Wigner function have been studied and applied for nonparaxial fields. In this thesis, a simple series expression for calculating a nonparaxial generalization of theWigner function from the standard Wigner function is developed in both two- and three-dimensional free space. A nonparaxial generalization of the ambiguity function that retains properties analogous to the standard ambiguity function is also proposed in both two and three dimensions. This generalization extends phase-space tomography to the nonparaxial regime. The second half of this thesis proposes a new method of coherence measurement based on diffraction. By measuring the radiant intensity of a field with and without a binary transparent phase mask, one can estimate the coherence of a field at all pairs of the points centered at the mask's edge. This method is proposed in

  5. LIDAR Wind Speed Measurements of Evolving Wind Fields

    SciTech Connect

    Simley, E.; Pao, L. Y.

    2012-07-01

    Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed Taylor's frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations to create a more realistic measurement model. A simple model of wind evolution is applied to a frozen wind field used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements are also evaluated with a large eddy simulation of a stable boundary layer provided by the National Center for Atmospheric Research. Simulation results show the combined effects of LIDAR errors and wind evolution for realistic turbine-mounted LIDAR measurement scenarios.

  6. Sub-micronewton thrust measurements of indium field emission thrusters

    NASA Technical Reports Server (NTRS)

    Ziemer, J. K.

    2003-01-01

    The performance of three indium field emission thrusters (In-FETs) developed by the Austrian Research Center Seibersdorf (ARCS) have been measured up to 200 muN, 2 mA, and 20 W using a submicronewton resolution thrust stand.

  7. Triggering for Magnetic Field Measurements of the LCLS Undulators

    SciTech Connect

    Hacker, Kirsten

    2010-12-13

    A triggering system for magnetic field measurements of the LCLS undulators has been built with a National Instruments PXI-1002 and a Xylinx FPGA board. The system generates single triggers at specified positions, regardless of encoder sensor jitter about a linear scale.

  8. 47 CFR 73.314 - Field strength measurements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ....314 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES FM Broadcast Stations § 73.314 Field strength measurements. (a) Except as provided for in § 73.209, FM broadcast stations shall not be protected from any type of interference or...

  9. 47 CFR 73.314 - Field strength measurements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....314 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES FM Broadcast Stations § 73.314 Field strength measurements. (a) Except as provided for in § 73.209, FM broadcast stations shall not be protected from any type of interference or...

  10. Work function measurements by the field emission retarding potential method

    NASA Technical Reports Server (NTRS)

    Swanson, L. W.; Strayer, R. W.; Mackie, W. A.

    1971-01-01

    Using the field emission retarding potential method true work functions have been measured for the following monocrystalline substrates: W(110), W(111), W(100), Nb(100), Ni(100), Cu(100), Ir(110) and Ir(111). The electron elastic and inelastic reflection coefficients from several of these surfaces have also been examined near zero primary beam energy.

  11. Transducer measures temperature differentials in presence of strong electromagnetic fields

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Measurement of temperature rise of cooling water under pressure and in strong electromagnetic fields is accomplished by a transducer using a magnetically shielded thermocouple arrangement. The thermocouple junctions are immersed in oil to isolate them from electric currents in the water.

  12. Functional Measurement in the Field of Empirical Bioethics

    ERIC Educational Resources Information Center

    Mullet, Etienne; Sorum, Paul C.; Teysseire, Nathalie; Nann, Stephanie; Martinez, Guadalupe Elizabeth Morales; Ahmed, Ramadan; Kamble, Shanmukh; Olivari, Cecilia; Sastre, Maria Teresa Munoz

    2012-01-01

    We present, in a synthetic way, some of the main findings from five studies that were conducted in the field of empirical bioethics, using the Functional Measurement framework. These studies were about (a) the rationing of rare treatments, (b) adolescents' abortions, (c) end-of-life decision-making regarding damaged neonates, (d) end-of-life…

  13. Hybrid spherical particle field measurement based on interference technology

    NASA Astrophysics Data System (ADS)

    Sun, Jinlu; Zhang, Hongxia; Li, Jiao; Zhou, Ye; Jia, Dagong; Liu, Tiegen

    2017-03-01

    Interferometric particle imaging is widely used in particle size measurement. Conventional algorithms, which focus on single size particle fields, have difficulties in extracting each interference fringe in a hybrid spherical particle field due to the noise. To solve this problem, an iterative mean filter (IMF) algorithm is proposed. Instead of the specific mean filter template coefficient, the noise is reduced by iterating the calculation results under different template coefficients. The average value of the calculation results excluding the gross error is output as the final result. The effect of different template coefficients are simulated, furthermore, the value range of template coefficients has been analyzed. The interferogram of the hybrid spherical particle field from 21.3 µm to 57.9 µm is processed by the conventional algorithms with specific template coefficients of 2, 8, 12 and the IMF algorithm. The corresponding measurement errors are 17.22%, 10.69%, 9.04% and 5.11%. The experimental results show that the IMF algorithm would reduce measurement error, and could be potentially applied in particle field measurement.

  14. Lidar Based Particulate Flux Measurements of Agricultural Field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A three-wavelength portable scanning lidar system was developed to derive information on particulate spatial aerosol distribution over remote distances. The lidar system and retrieval approach has been tested during several field campaigns measuring agricultural emissions from a swine feeding operat...

  15. Simple System to Measure the Earth's Magnetic Field

    ERIC Educational Resources Information Center

    Akoglu, R.; Halilsoy, M.; Mazharimousavi, S. Habib

    2010-01-01

    Our aim in this proposal is to use Faraday's law of induction as a simple lecture demonstration to measure the Earths magnetic field (B). This will also enable the students to learn about how electric power is generated from rotational motion. Obviously the idea is not original, yet it may be attractive in the sense that no sophisticated devices…

  16. Laser Measurements of Transient High-Strength Electric Fields

    DTIC Science & Technology

    1987-07-15

    Measurements of Electric Field Strength," Poster Session of Applied Spectroscopy (Miami Valley Section), University of Dayton, January 11, 1985. 2...Buswell, A. T., "Quantum Perturbation Theory of Stark- Induced Polarizability," Poster Session of Applied Spectroscopy (Miami Valley Section), University...34Theoretical Calculations of Stark- Induced Polarizabilities," Poster Session of Applied Spectroscopy (Miami Valley Section), The Ohio State University

  17. Comparing Laboratory and Field Measured Biota-sediment Accumulation Factors

    EPA Science Inventory

    The report presents a review of studies where biota-sediment accumulation factors (BSAFs) were measured in the field, and the same sediment samples were tested in the laboratory using sediment bioaccumulation testing protocols. The focus of this review was to document the extent...

  18. Global ionospheric electric field measurements in April 1978

    NASA Technical Reports Server (NTRS)

    Holzworth, R.; Kishi, A.; Wygant, J.; Mozer, F.; Gonzales, C.; Greenwald, R.; Blanc, M.; Vickrey, J.

    1981-01-01

    This paper presents an introduction to a global campaign of simultaneous quasi-static electric field measurements from radars, balloons, and satellites at various places within the earth's environment for April 8-14, 1978. The 7-day time period encompassed both extended magnetically quiet times as well as two magnetic storms. These storms were related to SSCs that followed solar flares, one of which included a day-long solar proton event. The wide variety of instrumentation and associated operating modes involved in this campaign is described. Sample conjunctions between satellites and ionospheric measurements are shown that demonstrate that field line mapping is valid under certain circumstances. Some of the largest ionospheric electric fields ever reported with greater than 100-km scale size occurred on April 11, and these events are discussed in detail.

  19. Measurements of magnetic field strengths in the vicinity of Orion

    NASA Astrophysics Data System (ADS)

    Heiles, C.; Troland, T. H.

    1982-09-01

    The line-of-sight magnetic field in two regions associated with the Orion Nebula was measured. One region is the large H I cloud which envelops the ionized and molecular clouds; the field strength is 10 microgauss. The other is the large CO cloud just south of the Orion Nebula discovered by Kutner, Tucker, and Chin (1977); the field strength here is also 10 microgauss. These results are discussed using the virial theorem. In the H I cloud, gravity appears to be weaker than the kinetic and magnetic forces, making this cloud unstable to expansion. In the CO cloud, gravity and the kinetic forces balance, and the magnetic field may be important in supporting the cloud.

  20. Project Vanguard Magnetic-Field Instrumentation and Measurements

    NASA Technical Reports Server (NTRS)

    Heppner, J. P.; Storarik, J. D.; Shapiro, I. R.; Cain, J. C.

    1960-01-01

    The Vanguard III Satellite, 1959 Eta, placed in orbit on September 18, 1959, contained a proton precessional magnetometer for magnetic-field studies of exceptional accuracy. Throughout the 85 days of battery life, the instrumentation functioned according to plan. Measurements of the absolute total field were obtained in the meridian belts of Minitrack stations at altitudes 510 to 3750 kilometers and at latitudes +/- 33.4 degrees. Surface magnetic observatories were operated at eight of the Minitrack stations to furnish correlative information. This paper reviews briefly the instrumentation employed in these experiments, and the data collection and reduction procedures. Emphasis is given to results from a preliminary analysis. Specifically, this analysis bears on the accuracy of computed fields, the stability of the earth's field in space, the Capetown anomaly, and magnetic-storm effects.

  1. Electric Field Measurements During the Genesis and Rapid Intensification Processes (GRIP) Field Program

    NASA Technical Reports Server (NTRS)

    Bateman, Monte G.; Blakeslee, Richard J.; Mach, Douglas M.

    2010-01-01

    During the Genesis and Rapid Intensification Processes (GRIP) field program, a system of 6 electric field mills was flown on one of NASA's Global Hawk aircraft. We placed several mills on the aircraft to enable us to measure the vector electric field. We created a distributed, ethernet-connected system so that each sensor has its own embedded Linux system, complete with web server. This makes our current generation system fully "sensor web enabled." The Global Hawk has several unique qualities, but relevant to quality storm electric field measurements are high altitude (20 km) and long duration (20-30 hours) flights. There are several aircraft participating in the GRIP program, and coordinated measurements are happening. Lightning and electric field measurements will be used to study the relationships between lightning and other storm characteristics. It has been long understood that lightning can be used as a marker for strong convective activity. Past research and field programs suggest that lightning flash rate may serve as an indicator and precursor for rapid intensification change in tropical cyclones and hurricanes. We have the opportunity to sample hurricanes for many hours at a time and observe intensification (or de-intensification) periods. The electrical properties of hurricanes during such periods are not well known. American

  2. Early results from ISEE-A electric field measurements

    NASA Technical Reports Server (NTRS)

    Heppner, J. P.; Maynard, N. C.; Aggson, T. L.

    1978-01-01

    In the solar wind and in middle latitude regions of the magnetosphere, spacecraft sheath fields obscure the ambient field under low plasma flux conditions such that valid measurements are confined to periods of moderately intense flux. Initial results show: (1) that the DC electric field is enhanced by roughly a factor of two in a narrow region at the front, increasing B, edge of the bow shock, (2) that scale lengths for large changes in E at the subsolar magnetopause are considerably shorter than scale lengths associated with the magnetic structure of the magnetopause, and (3) that the transverse distribution of B-aligned E-fields between the outer magnetosphere and ionospheric levels must be highly complex to account for the random turbulent appearance of the magnetospheric fields and the lack of corresponding time-space variations at ionospheric levels. Spike-like, non-oscillatory, fields lasting less than 0.2 seconds are occasionally seen at the bow shock and at the magnetopause and also intermittently appear in magnetosheath and plasma sheet regions under highly variable field conditions.

  3. Beta fields and measurement practices at DOE facilities

    NASA Astrophysics Data System (ADS)

    Swinth, K. L.; Rathbun, L. A.; Brackenbush, L. W.

    1985-09-01

    As part of a larger program, the beta measurement problem at DOE facilities was assessed through the use of a questionnaire and field visits to selected facilities. At 35% the facilities beta-emitting radionuclides can contribute enough to the radiation exposures that they must be considered in establishing protection requirements. Measurements were made in several facilities using scintillators, a surface barrier detector plus various dosimeters and survey instruments. Beta dose rates of several hundred mrad/hr were not unusual and beta:gamma ratios of greater than 30:1 were frequently observed. The agreement between the various measurement techniques was frequently unacceptable.

  4. Volume Perimetry: measurement in depth of visual field loss

    PubMed Central

    Satgunam, PremNandhini; Apfelbaum, Henry L; Peli, Eli

    2012-01-01

    Purpose Volume scotomas are three-dimensional regions of space that are not visible to the observer. Volume perimetry maps volume scotomas. Volume scotomas predicted from combining monocular visual fields assume known fixation locus (mainly foveal). However fixation loci are not always known, especially with central field loss. Here we demonstrate methods for measuring and calculating volume scotomas and discuss their practical implications. Methods Three patients (bitemporal hemianopia, binasal scotoma, and central field loss (CFL)) were evaluated. Slices through the volume scotomas were measured at three distances: at the plane of fixation, at a plane anterior to fixation (representing anterior volume perimetry), and a plane posterior to fixation (representing posterior volume perimetry). For anterior volume perimetry, patients fixated on a screen 100cm away through a beamsplitter that reflected the perimetric stimulus (at 50cm). For posterior volume perimetry, patients fixated on a near target (50cm) while perimetric stimuli were presented on a screen 150cm beyond the fixation. At the plane of fixation, monocular visual fields under binocular viewing conditions were measured using a computerized dichoptic perimeter. Results Posterior and anterior volume scotomas were documented in patients with bitemporal hemianopia and binasal scotomas respectively. The CFL patient demonstrated both anterior and posterior volume scotomas. Scotoma magnitude was considered to determine its effect on visual function. Conclusions Direct measurement of volume scotomas can be performed. Anterior and posterior volume visual fields can vary substantially from conventional binocular perimetry measured at the fixation plane, revealing blind areas not otherwise identified. These volume scotomas are likely to impair functional vision such as driving (for bitemporal hemianopes) and near work with small hand tools (for binasal scotomas). Patients with CFL will have impaired functional vision

  5. Thiopeptin, a New Feed-Additive Antibiotic: Biological Studies and Field Trials

    PubMed Central

    Mine, K.; Miyairi, N.; Takano, N.; Mori, S.; Watanabe, N.

    1972-01-01

    Thiopeptin is a new antibiotic, produced by Streptomyces tateyamensis and developed solely for animal use as a feed additive. The antibiotic content in animal tissue and feed was assayed in terms of the antimicrobial activity against Mycoplasma laidlawii A. This antibiotic was found to be relatively nontoxic in rats and mice. In chickens, this antibiotic is excreted into feces within 48 hr of administration and is not absorbed in tissue. It is well tolerated in both broilers and swine and is highly stable in animal feed. Thiopeptin-supplemented feed contributes to the improvement of weight gain, feed efficiency in chickens and swine, and the egg performance in layers. Thus, thiopeptin, when used as a feed additive, is quite suitable for supplementing animal nutrition. PMID:4680812

  6. An Approach to the Classification of Potential Reserve Additions of Giant Oil Fields of the World

    USGS Publications Warehouse

    Klett, T.R.; Tennyson, M.E.

    2008-01-01

    This report contains slides and notes for slides for a presentation given to the Committee on Sustainable Energy and the Ad Hoc Group of Experts on Harmonization of Fossil Energy and Mineral Resources Terminology on 17 October 2007 in Geneva, Switzerland. The presentation describes the U.S. Geological Survey study to characterize and quantify petroleum-reserve additions, and the application of this study to help classify the quantities.

  7. Field Method for Detection of Metal Deactivator Additive in Jet Fuel

    DTIC Science & Technology

    2009-04-01

    sulphonic acid on the silica support. The SCX stationary phase is a silica gel with propylbenzenesulfonyl groups bound to the silica, Figure 6. S O O O...They can be grouped into three main categories based on the property of the additive they are detecting. The categories are the; a. Dispersant...was less prominent when lower concentrations of MDA were used. The elution properties of the copper and nickel MDA complexes was examined in a range

  8. Imaging of Vector Electric Fields Surrounding Auroral Arcs from Multibeam Incoherent Scatter Radar Measurements.

    NASA Astrophysics Data System (ADS)

    Maksimova, N.; Varney, R. H.; Cosgrove, R. B.; Kaeppler, S. R.; Nicolls, M. J.

    2015-12-01

    Evaluating the ionospheric electric fields and current systems surrounding auroral arcs aids in distinguishing physical mechanisms that drive arc generation and current closure. Auroral forms involve spatial scales that are small in comparison with the magnetosphere-ionosphere-thermosphere (MIT) system, and yet these forms are thought to be closely tied to the overall system response. Spatially resolved measurements of the horizontal ionospheric current can, in principle, be used to determine the field-aligned currents (FAC) that are responsible for energy transfer between the magnetosphere and the ionosphere/thermosphere, leading to heating and upwelling of the neutral gas and acceleration of ion upflows and outflows. Furthermore, the closure of FACs in the ionosphere regulates modes of magnetospheric convection and substorms. An algorithm has been developed to image the local structure in the convection electric field using multibeam incoherent scatter radar (ISR) measurements. Given the inherent difficulty of reconstructing vector quantities from line of sight (LOS) velocity measurements, the algorithm's aim is to select from the solution space for the possible field configurations a unique solution for the electric field distribution by constraining the reconstructed electric field to reproduce the LOS measurements within measurement errors while simultaneously minimizing a measure of the field's curvature and absolute gradient. Using the method of Lagrange multipliers, the algorithm regularizes the underdetermined problem defined by the LOS radar velocity measurements and guarantees a unique solution when the average measurement error is smaller than the average measurement amplitude. The algorithm is tested on a variety of simulated fields in a sensitivity study to determine the extent to which the solution depends on the a priori assumptions and the observation geometry. In addition, a case study of a quiescent auroral arc observed by the Poker Flat

  9. Influence of relative humidity on analyzing electric field exposure using ELF electric field measurements.

    PubMed

    Korpinen, Leena H; Kuisti, Harri A; Tarao, Hiroo; Elovaara, Jarmo A

    2013-07-01

    The objective of the study was to investigate the influence of humidity on analyzing electric field exposure using extremely low frequency (ELF) electric field measurements. The study included 322 measurements in a climate room. We used two commercial three-axis meters, EFA-3 and EFA-300, and employed two measurement techniques in the climate room where we varied the temperature from 15 to 25 °C, the relative humidity from 55% to 95%, and the electric field from 1 to 25 kV/m. We calculated Pearson correlations between humidity and percentage errors for all data and for data at different levels of humidity. When the relative humidity was below 70%, the results obtained by the different measurement methods in terms of percentage errors were of the same order of magnitude for the considered temperatures and field strength, but the results were less reliable when the relative humidity was higher than 80%. In the future, it is important to take humidity into account when electric field measurement results will be compared to the values given in different exposure guidelines.

  10. Non-additivity of molecule-surface van der Waals potentials from force measurements

    PubMed Central

    Wagner, Christian; Fournier, Norman; Ruiz, Victor G.; Li, Chen; Müllen, Klaus; Rohlfing, Michael; Tkatchenko, Alexandre; Temirov, Ruslan; Tautz, F. Stefan

    2014-01-01

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive potential between differently sized organic molecules and a metal surface using an atomic force microscope. Our choice of molecules and the large molecule-surface separation cause this attraction to be purely of vdW type. The experiment allows testing the asymptotic vdW force law and its validity range. We find a superlinear growth of the vdW attraction with molecular size, originating from the increased deconfinement of electrons in the molecules. Because such non-additive vdW contributions are not accounted for in most first-principles or empirical calculations, we suggest further development in that direction. PMID:25424490

  11. Nonlinearity measurements of solar cells with an LED-based combinatorial flux addition method

    PubMed Central

    Hamadani, Behrang H.; Shore, Andrew; Roller, John; Yoon, Howard W; Campanelli, Mark

    2016-01-01

    We present a light emitting diode (LED)-based system utilizing a combinatorial flux addition method to investigate the nonlinear relationship in solar cells between the output current of the cell and the incident irradiance level. The magnitude of the light flux is controlled by the supplied currents to two LEDs (or two sets of them) in a combinatorial fashion. The signals measured from the cell are arranged within a related overdetermined linear system of equations derived from an appropriately chosen Nth degree polynomial representing the relationship between the measured signals and the incident fluxes. The flux values and the polynomial coefficients are then solved for by linear least squares to obtain the best fit. The technique can be applied to any solar cell, under either monochromatic or broadband spectrum. For the unscaled solution, no reference detectors or prior calibrations of the light flux are required. However, if at least one calibrated irradiance value is known, then the entire curve can be scaled to an appropriate spectral responsivity value. Using this technique, a large number of data points can be obtained in a relatively short time scale over a large signal range. PMID:27524837

  12. Nonlinearity measurements of solar cells with an LED-based combinatorial flux addition method.

    PubMed

    Hamadani, Behrang H; Shore, Andrew; Roller, John; Yoon, Howard W; Campanelli, Mark

    2016-02-01

    We present a light emitting diode (LED)-based system utilizing a combinatorial flux addition method to investigate the nonlinear relationship in solar cells between the output current of the cell and the incident irradiance level. The magnitude of the light flux is controlled by the supplied currents to two LEDs (or two sets of them) in a combinatorial fashion. The signals measured from the cell are arranged within a related overdetermined linear system of equations derived from an appropriately chosen N(th) degree polynomial representing the relationship between the measured signals and the incident fluxes. The flux values and the polynomial coefficients are then solved for by linear least squares to obtain the best fit. The technique can be applied to any solar cell, under either monochromatic or broadband spectrum. For the unscaled solution, no reference detectors or prior calibrations of the light flux are required. However, if at least one calibrated irradiance value is known, then the entire curve can be scaled to an appropriate spectral responsivity value. Using this technique, a large number of data points can be obtained in a relatively short time scale over a large signal range.

  13. AUV Turbulence Measurements in the LOCO Field Experiments

    DTIC Science & Technology

    2007-09-30

    addition the vehicle contains a variety of “hotel” sensors which measure pitch , roll , yaw, and other internal dynamical characteristics. This suite...hotel” sensors which measure pitch , roll , yaw, and many other internal characteristics. FFECT TO THE ENVIRONMENT E (1) Because the AUV is battery...upward and downward looking 1.2 mHz ADCP , a FASTCAT CTD, and a Wet Labs BB2F Combination Spectral Backscattering Meter/ Chlorophyll Fluorometer. In

  14. Magnetic field measurements near stand-alone transformer stations.

    PubMed

    Kandel, Shaiela; Hareuveny, Ronen; Yitzhak, Nir-Mordechay; Ruppin, Raphael

    2013-12-01

    Extremely low-frequency (ELF) magnetic field (MF) measurements around and above three stand-alone 22/0.4-kV transformer stations have been performed. The low-voltage (LV) cables between the transformer and the LV switchgear were found to be the major source of strong ELF MFs of limited spatial extent. The strong fields measured above the transformer stations support the assessment method, to be used in future epidemiological studies, of classifying apartments located right above the transformer stations as highly exposed to MFs. The results of the MF measurements above the ground around the transformer stations provide a basis for the assessment of the option of implementing precautionary procedures.

  15. Assessing Counter-Terrorism field training with multiple behavioral measures.

    PubMed

    Spiker, V Alan; Johnston, Joan H

    2013-09-01

    Development of behavioral pattern recognition and analysis skills is an essential element of Counter-Terrorism training, particularly in the field. Three classes of behavioral measures were collected in an assessment of skill acquisition during a US Joint Forces Command-sponsored course consisting of Combat Tracking and Combat Profiling segments. Measures included situational judgment tests, structured behavioral observation checklists, and qualitative assessments of the emergence of specific knowledge-skills-attitudes over the course of the training. The paper describes statistical evidence across the three types of measures that indicate that behavioral pattern recognition and analysis skills were successfully acquired by most students (a mix of Army and civilian law enforcement personnel) during the field training exercises. Implications for broader training of these critical skills are also discussed.

  16. Earth's field NMR flow meter: preliminary quantitative measurements.

    PubMed

    Fridjonsson, Einar O; Stanwix, Paul L; Johns, Michael L

    2014-08-01

    In this paper we demonstrate the use of Earth's field NMR (EF NMR) combined with a pre-polarising permanent magnet for measuring fast fluid velocities. This time of flight measurement protocol has a considerable history in the literature; here we demonstrate that it is quantitative when employing the Earth's magnetic field for signal detection. NMR signal intensities are measured as a function of flow rate (0-1m/s) and separation distance between the permanent magnet and the EF NMR signal detection. These data are quantitatively described by a flow model, ultimately featuring no free parameters, that accounts for NMR signal modulation due to residence time inside the pre-polarising magnet, between the pre-polarising magnet and the detection RF coil and inside the detection coil respectively. The methodology is subsequently demonstrated with a metallic pipe in the pre-polarising region.

  17. A Longitudinal Field Study Comparing a Multiplicative and an Additive Model of Motivation and Ability. Technical Report No. 11.

    ERIC Educational Resources Information Center

    Barrett, Gerald V.; And Others

    The relative contribution of motivation to ability measures in predicting performance criteria of sales personnel from successive fiscal periods was investigated. In this context, the merits of a multiplicative and additive combination of motivation and ability measures were examined. The relationship between satisfaction and motivation and…

  18. 34 CFR 350.55 - What are the additional considerations for selecting Field-Initiated Project applications for...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false What are the additional considerations for selecting Field-Initiated Project applications for funding? 350.55 Section 350.55 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION DISABILITY...

  19. 34 CFR 350.55 - What are the additional considerations for selecting Field-Initiated Project applications for...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Field-Initiated Project applications for funding? 350.55 Section 350.55 Education Regulations of the..., DEPARTMENT OF EDUCATION DISABILITY AND REHABILITATION RESEARCH PROJECTS AND CENTERS PROGRAM How Does the Secretary Make an Award? § 350.55 What are the additional considerations for selecting...

  20. Microcalorimetry: Wide Temperature Range, High Field, Small Sample Measurements

    NASA Astrophysics Data System (ADS)

    Hellman, Frances

    2000-03-01

    We have used Si micromachining techniques to fabricate devices for measuring specific heat or other calorimetric signals from microgram-quantity samples over a temperature range from 1 to 900K in magnetic fields to date up to 8T. The devices are based on a relatively robust silicon nitride membrane with thin film heaters and thermometers. Different types of thermometers are used for different purposes and in different temperature ranges. These devices are particularly useful for thin film samples (typically 200-400 nm thick at present) deposited directly onto the membrane through a Si micromachined evaporation mask. They have also been used for small single crystal samples attached by conducting grease or solder, and for powder samples dissolved in a solvent and dropped onto devices. The measurement technique used (relaxation method) is particularly suited to high field measurements because the thermal conductance can be measured once in zero field and is field independent, while the time constant of the relaxation does not depend on thermometer calibration. Present development efforts include designs which show promise for time-resolved calorimetry measurements of biological samples in small amounts of water. Samples measured to date include amorphous magnetic thin films (a-TbFe2 and giant negative magnetoresistance a-Gd-Si alloys), empty and filled fullerenes (C_60, K_3C_60, C_82, La@C_82, C_84, and Sc_2@C_84), single crystal manganites (La_1-xSr_xMnO_3), antiferromagnetic multilayers (NiO/CoO, NiO/MgO, and CoO/MgO), and nanoparticle magnetic materials (CoO in a Ag matrix).

  1. Measuring Energy Scaling of Laser Driven Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Williams, Jackson; Goyon, Clement; Mariscal, Derek; Pollock, Brad; Patankar, Siddharth; Moody, John

    2016-10-01

    Laser-driven magnetic fields are of interest in particle confinement, fast ignition, and ICF platforms as an alternative to pulsed power systems to achieve many times higher fields. A comprehensive model describing the mechanism responsible for creating and maintaining magnetic fields from laser-driven coils has not yet been established. Understanding the scaling of key experimental parameters such as spatial and temporal uniformity and duration are necessary to implement coil targets in practical applications yet these measurements prove difficult due to the highly transient nature of the fields. We report on direct voltage measurements of laser-driven coil targets in which the laser energy spans more than four orders of magnitude. Results suggest that at low energies, laser-driven coils can be modeled as an electric circuit; however, at higher energies plasma effects dominate and a simple circuit treatment is insufficient to describe all observed phenomenon. The favorable scaling with laser power and pulse duration, observed in the present study and others at kilojoule energies, has positive implications for sustained, large magnetic fields for applications on the NIF. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  2. Substituting EMC emission measurement by field and cable scan method using measured transfer function

    NASA Astrophysics Data System (ADS)

    Rinas, D.; Jia, J.; Zeichner, A.; Frei, S.

    2013-07-01

    Today EMC emissions of automotive components are often measured in anechoic chambers by an antenna at fixed position according to CISPR 25 (ALSE-method). The antenna voltage often cannot sufficiently describe the behaviour of the measured electronic components and systems. Furthermore space requirements and costs are very high for the ALSE-method. Field- and cable-scan methods combined with near-field to far-field transformation techniques might be a good alternative. Residual reflections from the walls, the metallic floor, the measuring table, interaction of the antenna with the environment, and other factors affect the measurements. Thus, models which only regard the current distribution for near- and far field calculation cannot produce results equal to a chamber measurement. In this paper methods for computing transfer functions for the substitution of EMC antenna measurements with field- and cable scans in a specified calibration area are introduced. To consider influences of the environment, the environment is characterized in a first step and included with transfer functions in the calculation process for the equivalent ALSE-field.

  3. High-precision measurements of global stellar magnetic fields

    NASA Astrophysics Data System (ADS)

    Plachinda, S. I.

    2014-06-01

    This paper presents a brief history of the development of devices and techniques for high-precision measurements of stellar magnetic fields. Two main approaches for the processing of spectral-polarimetric observations are described: the method of least-squares deconvolution (LSD), which is used to find a mean-weighted average of the normalized polarization profile using a set of spectral lines, and a method in which each individual spectral line is used to determine the magnetic field, viz., the single line method (SL). The advantages and disadvantages of the LSD and SL methods are discussed.

  4. Satellite measurements of the earth's crustal magnetic field

    NASA Technical Reports Server (NTRS)

    Schnetzler, C. C.

    1989-01-01

    The literature associated with the Magsat mission has evaluated the capabilities and limitations of satellite measurements of the earth's crustal magnetic field, and demonstrated that there exists a 300-3000 km magnetic field, related to major features in the earth's crust, which is primarily caused by induction. Due to its scale and sensitivity, satellite data have been useful in the development of models for such large crustal features as subduction zones, submarine platforms, continental accretion boundaries, and rifts. Attention is presently given to the lack of agreement between laboratory and satellite estimates of lower crustal magnetization.

  5. Field Geologist: An Android App for Measuring Rock Outcroppings

    NASA Astrophysics Data System (ADS)

    Baird, J.; Chiu, M. T.; Huang, X.; de Lanerolle, T. R.; Morelli, R.; Gourley, J. R.

    2011-12-01

    Field geologist is a mobile Android app that measures, plots, and exports strike and data in the field. When the phone is placed on the steepest part of the rock, it automatically detects dip, string, latitude and longitude. It includes a drop-down menu to record the type of rock. The app's initial screen displays a compass with an interior dip/strike symbol that always points toward the dip direction. Tapping the compass stores a data point in the phone's database. The points can be displayed on a Google map and uploaded to a server, from where they can be retrieved in CSV format and imported into a spreadsheet.

  6. Testing the Addition of Topographic Features for Field Scale Infiltration Excess Water Quality Modeling in SWAT

    NASA Astrophysics Data System (ADS)

    Collick, A.; Easton, Z. M.; Kleinman, P. J. A.; Sommerlot, A.; White, M. J.; Harmel, D.; Fuka, D.

    2014-12-01

    Watershed planners and managers need reliable tools that can capture the spatial and temporal complexity of agricultural landscapes, and water quality models are increasingly relied upon to represent P loss from agricultural watersheds. While a significant amount of modeling work has attempted to incorporate factors controlling P loss (e.g. representing solubility, manure types, timing and application type), these models still typically require significant calibration and are thus difficult to apply meaningfully in areas without copious data with which to calibrate. This is partially because these models were never really intended as field scale tools, while we are trying to use them to define different hydrologic pathways, area weighted potential energy (slopes and saturated conductivities), and the resulting lag time of P in different transport states. The movement of water within the landscape as surface (or near-surface) storm runoff and interflow is driven by gravity, topography, contributing area and soil and landuse characteristics, which play roles in concentrating water flows. Soil surveys have played a key role in the development of pedology and spatially derived pedon soil maps have become valuable datasets for natural resource management. Unfortunately, the soil surveys, commonly available at ~1:20,000 scale, are not designed to provide the high-resolution models of the soil continuum required in field scale environmental modeling applications and site specific crop and water quality management. The goal of this project is to test a methodology designed initially for representing saturation excess hydrology in the SWAT model to incorporate topographic attributes, and resulting spatially explicit soil morphology, that are missing from standard SWAT model initializations.

  7. Field Survey Measures of Olfaction: The Olfactory Function Field Exam (OFFE)

    PubMed Central

    Kern, David W.; Wroblewski, Kristen E.; Schumm, L. Philip; Pinto, Jayant M.; McClintock, Martha K.

    2016-01-01

    Population-based field research on human olfaction has been limited by a lack of feasible assessment tools. Previous olfactory survey research has measured only odor identification, with no research being done on odor detection (i.e., a person's sensitivity to detect a particular odor). Laboratory studies suggest that deficits in both aspects of olfactory function may be related to physical health, mental health and cognition, social function, including overall quality of life, and even mortality. However, field studies are needed to validate and extend these findings in large representative samples. Here we describe the olfactory function field exam, an instrument that can be deployed in field environments by lay interviewers to evaluate both odor identification and odor detection rapidly, practically, and accurately. Use of this new survey tool in future field-based population health studies will elucidate the impact of olfactory function on a myriad of health and social conditions. PMID:27226782

  8. Electric field variations during substorms: OGO-6 measurements

    NASA Technical Reports Server (NTRS)

    Heppner, J. P.

    1972-01-01

    The OGO-6 electric field measurements make it clear that the general pattern of high latitude electric fields in magnetic time-invariant latitude coordinates is not highly variable and that when unusual variations, or field distributions, occur they are relatively isolated in time and spatial extent. Thus, electric field changes on a global scale cannot, in general, be evoked as a direct cause of substorms. Polar traverses along the 18(h) to 6(h) magnetic time meridian show that the sum of potential drops across the evening auroral belt and morning auroral belt approximately equals the potential drop across the polar cap. The integrated polar cap potential drop ranges from 20 to 100 keV and values in the center of this range are most common under conditions of moderate magnetic disturbance. Roughly near 18(h) magnetic local time, a latitudinally narrow strip at the transition between auroral belt and polar cap fields exhibits unusually large field fluctuations immediately following the sudden onset of a negative bay at later magnetic local times. It appears likely that this spatially isolated correlation is related to an effect rather than a cause of substorm enhancement.

  9. Field Measurements of Terrestrial and Martian Dust Devils

    NASA Astrophysics Data System (ADS)

    Murphy, Jim; Steakley, Kathryn; Balme, Matt; Deprez, Gregoire; Esposito, Francesca; Kahanpää, Henrik; Lemmon, Mark; Lorenz, Ralph; Murdoch, Naomi; Neakrase, Lynn; Patel, Manish; Whelley, Patrick

    2016-11-01

    Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types.

  10. The Synthesis of Structural Responses Using Experimentally Measured Frequency Response Functions and Field Test Data

    SciTech Connect

    CAP,JEROME S.; NELSON,CURTIS F.

    2000-11-17

    This paper presents an analysis technique used to generate the structural response at locations not measured during the ejection of a captive-carried store. The ejection shock event is complicated by the fact that forces may be imparted to the store at eight distinct locations. The technique derives forcing functions by combining the initial field test data for a limited number of measurement locations with Frequency Response Functions (FRFs) measured using a traditional modal-type impact (tap) test at the same locations. The derived forcing functions were then used with tap test FRFs measured at additional locations of interest to produce the desired response data.

  11. Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake

    SciTech Connect

    Mulholland, Patrick J; Hall, Robert; Tank, Jennifer; Sobota, Daniel; O'Brien, Jon; Webster, Jackson; Valett, H. Maurice; Dodds, Walter; Poole, Geoff; Peterson, Chris G.; Meyer, Judy; McDowell, William; Johnson, Sherri; Hamilton, Stephen; Gregory, Stanley; Grimm, Nancy; Dahm, Cliff; Cooper, Lee W; Ashkenas, Linda; Thomas, Suzanne; Sheibley, Rich; Potter, Jody; Niederlehner, Bobbie; Johnson, Laura; Helton, Ashley; Crenshaw, Chelsea; Burgin, Amy; Bernot, Melody; Beaulieu, Jake; Arango, Clay

    2009-01-01

    We measured uptake length of {sup 15}NO{sub 3}{sup -} in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO{sub 3}{sup -} uptake length. As part of the Lotic Intersite Nitrogen Experiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO{sub 3}{sup -} concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO{sub 3}{sup -} uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79% of the variation in log uptake length (S{sub Wtot}). Uptake length increased with specific discharge (Q/w) and increasing NO{sub 3}{sup -} concentrations, showing a loss in removal efficiency in streams with high NO{sub 3}{sup -} concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO{sub 3}{sup -} removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO{sub 3}{sup -} uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO{sub 3}{sup -} uptake lengths via directly increasing both gross primary production and NO{sub 3}{sup -} concentration. Gross primary production shortened S{sub Wtot}, while increasing NO{sub 3}{sup -} lengthened S{sub Wtot} resulting in no net effect of land use on NO{sub 3}{sup -} removal.

  12. Modeling particulate matter concentrations measured through mobile monitoring in a deletion/substitution/addition approach

    NASA Astrophysics Data System (ADS)

    Su, Jason G.; Hopke, Philip K.; Tian, Yilin; Baldwin, Nichole; Thurston, Sally W.; Evans, Kristin; Rich, David Q.

    2015-12-01

    Land use regression modeling (LUR) through local scale circular modeling domains has been used to predict traffic-related air pollution such as nitrogen oxides (NOX). LUR modeling for fine particulate matters (PM), which generally have smaller spatial gradients than NOX, has been typically applied for studies involving multiple study regions. To increase the spatial coverage for fine PM and key constituent concentrations, we designed a mobile monitoring network in Monroe County, New York to measure pollutant concentrations of black carbon (BC, wavelength at 880 nm), ultraviolet black carbon (UVBC, wavelength at 3700 nm) and Delta-C (the difference between the UVBC and BC concentrations) using the Clarkson University Mobile Air Pollution Monitoring Laboratory (MAPL). A Deletion/Substitution/Addition (D/S/A) algorithm was conducted, which used circular buffers as a basis for statistics. The algorithm maximizes the prediction accuracy for locations without measurements using the V-fold cross-validation technique, and it reduces overfitting compared to other approaches. We found that the D/S/A LUR modeling approach could achieve good results, with prediction powers of 60%, 63%, and 61%, respectively, for BC, UVBC, and Delta-C. The advantage of mobile monitoring is that it can monitor pollutant concentrations at hundreds of spatial points in a region, rather than the typical less than 100 points from a fixed site saturation monitoring network. This research indicates that a mobile saturation sampling network, when combined with proper modeling techniques, can uncover small area variations (e.g., 10 m) in particulate matter concentrations.

  13. Effect of silica fume addition on the PGNAA measurement of chlorine in concrete.

    PubMed

    Naqvi, A A; Maslehuddin, M; Garwan, M A; Nagadi, M M; Al-Amoudi, O S B; Raashid, M; Khateeb-ur-Rehman

    2010-03-01

    Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to Portland cement in concrete to prevent reinforcement steel corrosion in concrete. Further preventive measure against reinforcement steel corrosion require monitoring of chloride salts concentration in concrete using non-destructive techniques, such as the prompt gamma-ray neutron activation analysis (PGNAA) technique. Due to interferences between gamma-rays from chlorine and calcium in PGNAA technique, detection limit of chlorine in concrete strongly depends upon calcium concentration in concrete. SF mainly contains silica and its addition to cement concrete reduces overall concentration of calcium in concrete. This may result in an improvement in detection limit of chlorine in SF-based concrete in PGNAA studies. Particularly for chlorine detection using 6.11 and 6.62 MeV prompt gamma-rays that strongly interfere with 6.42 MeV prompt gamma-rays from calcium. In this study, SF was added to Portland cement to prevent concrete reinforcement steel from corrosion. The chlorine concentration in SF cement concrete specimens containing 0.2-3.0 wt% chlorine was measured through yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV chlorine gamma-rays using PGNAA technique. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the gamma-ray yield calculated through the Monte Carlo simulations. Further the minimum detectable concentration (MDC) of chlorine in SF cement concrete was calculated and compared with the MDC values of chlorine in plain concrete and concrete mixed with fly ash cement. The MDC of chlorine in SF-based concrete through 6.11 MeV, and 6.62 MeV chlorine gamma-rays was found to be improved as compared to those in plain concrete and concrete mixed with fly ash cement.

  14. Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake

    USGS Publications Warehouse

    Hall, R.O.; Tank, J.L.; Sobota, D.J.; Mulholland, P.J.; O'Brien, J. M.; Dodds, W.K.; Webster, J.R.; Valett, H.M.; Poole, G.C.; Peterson, B.J.; Meyer, J.L.; McDowell, W.H.; Johnson, S.L.; Hamilton, S.K.; Grimm, N. B.; Gregory, S.V.; Dahm, Clifford N.; Cooper, L.W.; Ashkenas, L.R.; Thomas, S.M.; Sheibley, R.W.; Potter, J.D.; Niederlehner, B.R.; Johnson, L.T.; Helton, A.M.; Crenshaw, C.M.; Burgin, A.J.; Bernot, M.J.; Beaulieu, J.J.; Arangob, C.P.

    2009-01-01

    We measured uptake length of 15NO-3 in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO-3 uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO-3 concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO-3 uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79% of the variation in log uptake length (S Wtot). Uptake length increased with specific discharge (Q/w) and increasing NO-3 concentrations, showing a loss in removal efficiency in streams with high NO-3 concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO-3 removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO-3 uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO-3 uptake lengths via directly increasing both gross primary production and NO-3 concentration. Gross primary production shortened SWtot, while increasing NO-3 lengthened SWtot resulting in no net effect of land use on NO- 3 removal. ?? 2009.

  15. Calibrating 100 Years of Polar Faculae Measurements: Implications for the Evolution of the Heliospheric Magnetic Field

    NASA Astrophysics Data System (ADS)

    Muñoz-Jaramillo, Andrés; Sheeley, Neil R.; Zhang, Jie; DeLuca, Edward E.

    2012-07-01

    Although the Sun's polar magnetic fields are thought to provide important clues for understanding the 11 year sunspot cycle, including the observed variations of its amplitude and period, the current database of high-quality polar field measurements spans relatively few sunspot cycles. In this paper, we address this deficiency by consolidating Mount Wilson Observatory polar faculae data from four data reduction campaigns, validating it through a comparison with facular data counted automatically from Michelson Doppler Imager (MDI) intensitygrams, and calibrating it against polar field measurements taken by the Wilcox Solar Observatory and average polar field and total polar flux calculated using MDI line-of-sight magnetograms. Our results show that the consolidated polar facular measurements are in excellent agreement with both polar field and polar flux estimates, making them an ideal proxy to study the evolution of the polar magnetic field. Additionally, we combine this database with sunspot area measurements to study the role of the polar magnetic flux in the evolution of the heliospheric magnetic field (HMF). We find that there is a strong correlation between HMF and polar flux at solar minimum and that, taken together, polar flux and sunspot area are better at explaining the evolution of the HMF during the last century than sunspot area alone.

  16. CALIBRATING 100 YEARS OF POLAR FACULAE MEASUREMENTS: IMPLICATIONS FOR THE EVOLUTION OF THE HELIOSPHERIC MAGNETIC FIELD

    SciTech Connect

    Munoz-Jaramillo, Andres; DeLuca, Edward E.; Sheeley, Neil R.; Zhang, Jie E-mail: edeluca@cfa.harvard.edu E-mail: jzhang7@gmu.edu

    2012-07-10

    Although the Sun's polar magnetic fields are thought to provide important clues for understanding the 11 year sunspot cycle, including the observed variations of its amplitude and period, the current database of high-quality polar field measurements spans relatively few sunspot cycles. In this paper, we address this deficiency by consolidating Mount Wilson Observatory polar faculae data from four data reduction campaigns, validating it through a comparison with facular data counted automatically from Michelson Doppler Imager (MDI) intensitygrams, and calibrating it against polar field measurements taken by the Wilcox Solar Observatory and average polar field and total polar flux calculated using MDI line-of-sight magnetograms. Our results show that the consolidated polar facular measurements are in excellent agreement with both polar field and polar flux estimates, making them an ideal proxy to study the evolution of the polar magnetic field. Additionally, we combine this database with sunspot area measurements to study the role of the polar magnetic flux in the evolution of the heliospheric magnetic field (HMF). We find that there is a strong correlation between HMF and polar flux at solar minimum and that, taken together, polar flux and sunspot area are better at explaining the evolution of the HMF during the last century than sunspot area alone.

  17. Simple System to Measure the Earth's Magnetic Field

    NASA Astrophysics Data System (ADS)

    Akoglu, R.; Halilsoy, M.; Mazharimousavi, S. Habib

    2010-11-01

    Our aim in this proposal is to use Faraday's law of induction as a simple lecture demonstration to measure the Earths magnetic field (B). This will also enable the students to learn about how electric power is generated from rotational motion. Obviously the idea is not original, yet it may be attractive in the sense that no sophisticated devices are used. All the equipment needed is available in an elementary physics laboratory and is displayed in Fig. 1. The square wooden coil and handmade belt system to rotate the coil may require some craftsmanship; once made, it can be used for years. Using a compass, we first orient the table parallel to the direction of the Earth's horizontal component of B field. This is necessary to maximize the Earth's field which can suppress the noise effects as much as possible. It is preferable to minimize also any environmental effects by conducting the experiment away from power lines, if possible of course.

  18. Calculation and measurement of electric field under HVDC transmission lines

    NASA Astrophysics Data System (ADS)

    Kasdi, A.; Zebboudj, Y.; Yala, H.

    2007-03-01

    A stable corona discharge in a two conductors-to-plane configuration is analysed in this paper. A linear biased probe, without end-effect, has been adapted to a linear geometry and is used for the first time to measure the ground-plane current density and electric field during the bipolar corona. The values of the electric field and the current density are maximum under the two coronating conductors and decrease when moving away from them. Furthermore, a hybrid technique is developed to obtain a general solution of the governing equations of the coupled space-charge and electric field problem. The technique is to use the finite-element method (FEM) to solve Poisson's equation, and the method of characteristic (MOC) to find the charge density from a current-continuity relation. The model avoids resorting to the Deutsch assumption. The computed values are in good agreement with experimental data.

  19. Calculated and measured fields in superferric wiggler magnets

    SciTech Connect

    Blum, E.B.; Solomon, L.

    1995-02-01

    Although Klaus Halbach is widely known and appreciated as the originator of the computer program POISSON for electromagnetic field calculation, Klaus has always believed that analytical methods can give much more insight into the performance of a magnet than numerical simulation. Analytical approximations readily show how the different aspects of a magnet`s design such as pole dimensions, current, and coil configuration contribute to the performance. These methods yield accuracies of better than 10%. Analytical methods should therefore be used when conceptualizing a magnet design. Computer analysis can then be used for refinement. A simple model is presented for the peak on-axis field of an electro-magnetic wiggler with iron poles and superconducting coils. The model is applied to the radiator section of the superconducting wiggler for the BNL Harmonic Generation Free Electron Laser. The predictions of the model are compared to the measured field and the results from POISSON.

  20. Laboratory and field methods for measuring human energy expenditure.

    PubMed

    Leonard, William R

    2012-01-01

    Energetics research is central to the field of human biology. Energy is an important currency for measuring adaptation, because both its acquisition and allocation for biological processes have important implications for survival and reproduction. Recent technological and methodological advances are now allowing human biologists to study variation in energy dynamics with much greater accuracy in a wide variety of ecological contexts. This article provides an overview of the methods used for measuring human energy expenditure (EE) and considers some of the important ecological and evolutionary questions that can be explored from an energetics perspective. Basic principles of calorimetry are first presented, followed by an overview of the equipment used for measuring human EE and work capacity. Methods for measuring three important dimensions of human EE-resting metabolic rate, working/exercising EE, and total EE-are then presented, highlighting key areas of ongoing research.

  1. Aircraft measurements and analysis of severe storms: 1975 field experiment

    NASA Technical Reports Server (NTRS)

    Sinclair, P. C.

    1976-01-01

    Three aircraft and instrumentation systems were acquired in support of the severe storm surveillance program. The data results indicate that the original concept of a highly mobile research aircraft capability for obtaining detailed measurements of wind, temperature, dew point, etc., near and within specifically designated severe storms is entirely feasible and has been demonstrated for the first time by this program. This program is unique in that it is designed to be highly mobile in order to move to and/or with the developing storm systems to obtain the necessary measurements. Previous programs have all been fixed to a particular location and therefore have had to wait for the storms to come within their network. The present research is designed around a highly mobile aircraft measurements group in order to maximize the storm cases during the field measurements program.

  2. Experimental studies on near-field holographic antenna measurement

    NASA Astrophysics Data System (ADS)

    Zuo, Yingxi; Xu, Linfen; An, Hongye; Sun, Jixian; Lou, Zheng; Yang, Ji; Zhang, Xuguo; Li, Zhenqiang; Lu, Dengrong; Pang, Xinghai; Li, Yang

    2016-07-01

    A near-field millimeter-wave holography system operating in the 3-mm waveband have been developed as a prototype for DATE5, a 5-m terahertz telescope proposed to be deployed at Dome A, Antarctica. Experimental measurements at 92 GHz have been made on a 1.45-m test antenna. During the night time at which the ambient temperature doesn't vary rapidly, a 75-minute repeatability (repeating measurement 3 times) of 2.3 μm rms has been achieved with an aperture resolution of 46 mm. A local surface change of known value is correctly detected. After long-time repeating measurements, thermal-induced feed displacement is also detected with an accuracy of approximately 20 μm. Random error factors of the experiment system are evaluated and their contributions to the derived surface error are also simulated, showing that relative poor pointing of the test antenna is the major factor limiting the measurement repeatability.

  3. Performance evaluation of RF electric and magnetic field measuring instruments

    NASA Astrophysics Data System (ADS)

    Nesmith, B. C. W.; Ruggers, P. S.

    1982-03-01

    The need to quantify the electromagnetic fields emitted by industrial, scientific, or medical (ISM) products operating in the 10 to 300 MHs region requires the testing of instrumentation suitable for use in RF radiation hazard surveys. To meet this requirement, several procedures were devised to test the accuracy of the RF survey instrumentation. Measurement systems and protocols were developed and evaluated. The electric (E) an magnetic (H) field measuring instruments were tested for linearity, calibration accuracy, amplitude modulation response, directivity, antenna patterns, temperature response, drift and noise, radiofrequency interference and polarization response. Tests were performed on three commercially available RF survey instruments and a one-of-a-kind device over the 10 to 100 MHs region. Complete tests were only performed at the ISM frequency of 27.12 MHs. Errors for each of the tests are presented in tabular form.

  4. Measuring the complete force field of an optical trap.

    PubMed

    Jahnel, Marcus; Behrndt, Martin; Jannasch, Anita; Schäffer, Erik; Grill, Stephan W

    2011-04-01

    The use of optical traps to measure or apply forces on the molecular level requires a precise knowledge of the trapping force field. Close to the trap center, this field is typically approximated as linear in the displacement of the trapped microsphere. However, applications demanding high forces at low laser intensities can probe the light-microsphere interaction beyond the linear regime. Here, we measured the full nonlinear force and displacement response of an optical trap in two dimensions using a dual-beam optical trap setup with back-focal-plane photodetection. We observed a substantial stiffening of the trap beyond the linear regime that depends on microsphere size, in agreement with Mie theory calculations. Surprisingly, we found that the linear detection range for forces exceeds the one for displacement by far. Our approach allows for a complete calibration of an optical trap.

  5. Hydrotest measurement system for gas lines gets field trials

    SciTech Connect

    Hodges, A.H. )

    1989-08-07

    Texas Gas Transmission Co., Owensboro, Ky., has developed a tool for recording and documenting the performance of hydrostatic testing. Texas Gas conducted field tests during the summer of 1988 and has continued those tests this year. The hydrostatic-test measurement system (HTMS) is designed to be more compact and easier to use than existing systems. With a Tandy 200 portable lap-top computer, software developed in-house, and other company-fabricated interface hardware, the portable data-acquisition system will measure and record field hydrostatic-test data. After the test, the computer will generate a stress-strain plot (pressure-vs.-gallon count) with a graphics plotter and print the test data.

  6. Mental self-government: development of the additional democratic learning style scale using Rasch measurement models.

    PubMed

    Nielsen, Tine; Kreiner, Svend; Styles, Irene

    2007-01-01

    This paper describes the development and validation of a democratic learning style scale intended to fill a gap in Sternberg's theory of mental self-government and the associated learning style inventory (Sternberg, 1988, 1997). The scale was constructed as an 8-item scale with a 7-category response scale. The scale was developed following an adapted version of DeVellis' (2003) guidelines for scale development. The validity of the Democratic Learning Style Scale was assessed by items analysis using graphical loglinear Rasch models (Kreiner and Christensen, 2002, 2004, 2006) The item analysis confirmed that the full 8-item revised Democratic Learning Style Scale fitted a graphical loglinear Rasch model with no differential item functioning but weak to moderate uniform local dependence between two items. In addition, a reduced 6-item version of the scale fitted the pure Rasch model with a rating scale parameterization. The revised Democratic Learning Style Scale can therefore be regarded as a sound measurement scale meeting requirements of both construct validity and objectivity.

  7. Verifying a Simplified Fuel Oil Flow Field Measurement Protocol

    SciTech Connect

    Henderson, H.; Dentz, J.; Doty, C.

    2013-07-01

    The Better Buildings program is a U.S. Department of Energy program funding energy efficiency retrofits in buildings nationwide. The program is in need of an inexpensive method for measuring fuel oil consumption that can be used in evaluating the impact that retrofits have in existing properties with oil heat. This project developed and verified a fuel oil flow field measurement protocol that is cost effective and can be performed with little training for use by the Better Buildings program as well as other programs and researchers.

  8. Verifying a Simplified Fuel Oil Field Measurement Protocol

    SciTech Connect

    Henderson, Hugh; Dentz, Jordan; Doty, Chris

    2013-07-01

    The Better Buildings program is a U.S. Department of Energy program funding energy efficiency retrofits in buildings nationwide. The program is in need of an inexpensive method for measuring fuel oil consumption that can be used in evaluating the impact that retrofits have in existing properties with oil heat. This project developed and verified a fuel oil flow field measurement protocol that is cost effective and can be performed with little training for use by the Better Buildings program as well as other programs and researchers.

  9. Airborne water vapor DIAL research: System development and field measurements

    NASA Technical Reports Server (NTRS)

    Higdon, Noah S.; Browell, Edward V.; Ponsardin, Patrick; Chyba, Thomas H.; Grossmann, Benoist E.; Butler, Carolyn F.; Fenn, Marta A.; Mayor, Shane D.; Ismail, Syed; Grant, William B.

    1992-01-01

    This paper describes the airborne differential absorption lidar (DIAL) system developed at the NASA Langley Research Center for remote measurement of water vapor (H2O) and aerosols in the lower atmosphere. The airborne H2O DIAL system was flight tested aboard the NASA Wallops Flight Facility (WFF) Electra aircraft in three separate field deployments between 1989 and 1991. Atmospheric measurements were made under a variety of atmospheric conditions during the flight tests, and several modifications were implemented during this development period to improve system operation. A brief description of the system and major modifications will be presented, and the most significant atmospheric observations will be described.

  10. Ocean wind field measurement performance of the ERS-1 scatterometer

    NASA Technical Reports Server (NTRS)

    Hans, P.; Schuessler, H.

    1984-01-01

    The Active Microwave Instrumentation (AMI), which will be implemented on the ERS-1, is a 5.3 GHz multipurpose radar for land surface imaging, ocean wave spectrum measurement and wind observations over oceans. The imaging and wave measurements apply Synthetic Aperture Radar (SAR) techniques, while wind field detection is performed by the Scatterometer as part of the AMI. The Scatterometer system design was developed and optimized with the aid of a performance simulator. This paper, aimed at giving an overview, is presented about the: (1) ERS-1 Scatterometer system design; (2) Error budget; and the (3) Overall calibration concept.

  11. Neutron Field Measurements in Phantom with Foil Activation Methods.

    DTIC Science & Technology

    1986-11-29

    jI25 Ii III uumu ullli~ S....- - Lb - w * .qJ’ AD-A 192 122 ulJ. IL (pj DNA-TR-87- 10 N EUTRON FIELD MEASUREMENTS IN PHANTOM WITH FOIL ACTIVATION...SAND II Measurements in Phantom 6 4 The 5-Foil Neutron Dosimetry Method 29 5 Comparison of SAND II and Simple 5-Foil Dosimetry Method 34 6 Thermal ...quite reasonable. The monkey phantom spectrum differs from the NBS U-235 fission spectrum in that the former has a I/E tail plus thermal -neutron peak

  12. Laser Velocimetry Measurements of Oscillating Airfoil Dynamic Stall Flow Field

    DTIC Science & Technology

    1991-06-01

    Velocimetry Measurements of Oscillating Airfoil Dynamic Stall Flow Field By M.S.Chandrasekharal Navy-NASA Joint Institute of Aeronautics and Fluid Mechanics ...tunnel of the Fluid Mechanics Laboratory(FML) angle information. The other could be used for the at NASA Ames Research Center (ARC). It is one of...were on throat is always kept choked so that no disturbances a different traverse mechanism , but this was driven as can propagate upstream into the

  13. A Comparative Kirkwood-Buff Study of Aqueous Methanol Solutions Modeled by the CHARMM Additive and Drude Polarizable Force Fields

    PubMed Central

    Lin, Bin; He, Xibing; MacKerell, Alexander D.

    2013-01-01

    A comparative study on aqueous methanol solutions modeled by the CHARMM additive and Drude polarizable force fields was carried out by employing Kirkwood-Buff analysis. It was shown that both models reproduced the experimental Kirkwood-Buff integrals and excess coordination numbers adequately well over the entire concentration range. The Drude model showed significant improvement over the additive model in solution densities, partial molar volumes, excess molar volumes, concentration-dependent diffusion constants, and dielectric constants. However, the additive model performed somewhat better than the Drude model in reproducing the activity derivative, excess molar Gibbs energy and excess molar enthalpy of mixing. This is due to the additive achieving a better balance among solute-solute, solute-solvent, and solvent-solvent interactions, indicating the potential for improvements in the Drude polarizable alcohol model. PMID:23947568

  14. Electric Field Double Probe Measurements on Satellites with Very Low Perigees

    NASA Technical Reports Server (NTRS)

    Pfaff, R. F., Jr.; Freundenreich, H.; Manzer, D.; Pankow, D.; Walsh, G.

    1999-01-01

    Measurements of DC and AC electric Fields at low altitudes (less than 150 km) in the Earth's ionosphere address a wide array of important scientific questions including Joule Heating, the closure of field aligned currents, and the deviation of E x B electron velocities from ion velocity vectors influenced by collisions. Double probes represent a well-proven technique for gathering high quality DC and AC electric field measurements for which the design of the boom system is of critical importance for the success of the experiment. In general, ionospheric DC electric field instruments that achieve accuracies of 0.1 mV/m or better, place sensors at large distances from the spacecraft body in order to extend well beyond the spacecraft wake and sheath and to achieve the large signal-to-noise ratios for DC and long wavelength measurements. Additional sets of sensors inboard of the primary, outermost sensors provide useful additional information, both for diagnostics of the plasma contact potentials, which particularly enhance the DC electric field measurements on non-spinning spacecraft, and for wavelength and phase velocity measurements that use the spaced receiver or "Interferometer" technique. Accurate attitude knowledge enables V x B contributions to be subtracted from the measured potentials, and permits the measured components to be rotated into meaningful geophysical reference frames. This presentation discusses the expected performance of electric field double probe experiments and their boom mechanisms on both spinning and non-spinning satellite platforms with very low perigees. Careful selection of probe surface materials, such as titanium nitride, for the low perigee environment, as well as thermal considerations are also discussed.

  15. Measuring microbial fitness in a field reciprocal transplant experiment.

    PubMed

    Boynton, Primrose J; Stelkens, Rike; Kowallik, Vienna; Greig, Duncan

    2016-06-22

    Microbial fitness is easy to measure in the laboratory, but difficult to measure in the field. Laboratory fitness assays make use of controlled conditions and genetically modified organisms, neither of which are available in the field. Among other applications, fitness assays can help researchers detect adaptation to different habitats or locations. We designed a competitive fitness assay to detect adaptation of Saccharomyces paradoxus isolates to the habitat they were isolated from (oak or larch leaf litter). The assay accurately measures relative fitness by tracking genotype frequency changes in the field using digital droplet PCR (DDPCR). We expected locally adapted S. paradoxus strains to increase in frequency over time when growing on the leaf litter type from which they were isolated. The DDPCR assay successfully detected fitness differences among S. paradoxus strains, but did not find a tendency for strains to be adapted to the habitat they were isolated from. Instead, we found that the natural alleles of the hexose transport gene we used to distinguish S. paradoxus strains had significant effects on fitness. The origin of a strain also affected its fitness: strains isolated from oak litter were generally fitter than strains from larch litter. Our results suggest that dispersal limitation and genetic drift shape S. paradoxus populations in the forest more than local selection does, although further research is needed to confirm this. Tracking genotype frequency changes using DDPCR is a practical and accurate microbial fitness assay for natural environments.

  16. Analysis and measurement of the 3D magnetic field in a rotating magnetic field driven FRC

    NASA Astrophysics Data System (ADS)

    Velas, K. M.; Milroy, R. D.

    2012-10-01

    A translatable three-axis probe was installed on TCSU shortly before its shutdown. The probe has 90 windings that simultaneously measure Br, Bθ, and Bz at 30 radial positions. Positioning the probe at multiple axial positions and taking multiple repeatable shots allows for a full r-z map of the magnetic field. Probe measurements are used to calculate the end-shorting torque and the rotating magnetic field (RMF) torque. The torque applied to the plasma is the RMF torque reduced by the shorting torque. An estimate of the plasma resistivity is made based on the steady state balance between the applied torque and the resistive torque. The steady state data from applying a 10 kHz low pass filter used in conjunction with data at the RMF frequency yields a map of the full 3D rotating field structure. Data from even- and odd-parity experiments will be presented. The NIMROD code has been adapted to simulate the TCSU experiment using boundary conditions adjusted to match both even- and odd-parity experimental conditions. A comparison of the n=0 components of the calculated fields to the 3-axis probe measurements shows agreement in the magnetic field structure of the FRC as well as in the jet region.

  17. Infrared image denoising applied in infrared sound field measurement

    NASA Astrophysics Data System (ADS)

    Su, Zhiqiang; Shen, Guofeng

    2017-03-01

    The research made use of the heat property and explored the distribution of focused ultrasound field. In our experiments, we measured the distribution of heat sources, and then, calculated the distribution of focused ultrasound field via a liner relation. In the experiments, we got a series of infrared images with noise. It's such an important thing to find out a solution to get rid of the noise in those images in order to get an accurate focused ultrasound field distribution. So the investigation following is focused in finding out a filter which can remove most noise in the infrared charts and the distribution of ultrasound filed is not impacted. Experiments compared the effects of different filters by the index of - 6dB width of the temperature rise images. By this index, we can find out a filter which is the most suitable filter for keeping the distribution of focused ultrasound field in steady. All experiments, including simulations, semi-simulations and actual verification experiments used six filters to deal with the raw data to get -6dB width and signal to noise ratio. From the results of experiments, we drew a conclusion that gauss filter is the best to keep the distribution of focused ultrasound field in steady.

  18. Review on measurement techniques of transport properties of nanowires Additions and Corrections. See DOI:10.1039/C3NR03242F Click here for additional data file.

    PubMed Central

    Rojo, Miguel Muñoz; Calero, Olga Caballero; Lopeandia, A. F.; Rodriguez-Viejo, J.

    2013-01-01

    Physical properties at the nanoscale are novel and different from those in bulk materials. Over the last few decades, there has been an ever growing interest in the fabrication of nanowire structures for a wide variety of applications including energy generation purposes. Nevertheless, the study of their transport properties, such as thermal conductivity, electrical conductivity or Seebeck coefficient, remains an experimental challenge. For instance, in the particular case of nanostructured thermoelectrics, theoretical calculations have shown that nanowires offer a promising way of enhancing the hitherto low efficiency of these materials in the conversion of temperature differences into electricity. Therefore, within the thermoelectrical community there has been a great experimental effort in the measurement of these quantities in actual nanowires. The measurements of these properties at the nanoscale are also of interest in fields other than energy, such as electrical components for microchips, field effect transistors, sensors, and other low scale devices. For all these applications, knowing the transport properties is mandatory. This review deals with the latest techniques developed to perform the measurement of these transport properties in nanowires. A thorough overview of the most important and modern techniques used for the characterization of different kinds of nanowires will be shown. PMID:24113712

  19. Measurements of middle-atmosphere electric fields and associated electrical conductivities

    NASA Technical Reports Server (NTRS)

    Hale, L. C.; Croskey, C. L.; Mitchell, J. D.

    1981-01-01

    A simple antenna for measuring the vertical electric field in the 'middle atmosphere' has been flown on a number of rocket-launched parachute-borne payloads. The data from the first nine such flights, launched under a variety of geophysical conditions, are presented, along with electrical conductivities measured simultaneously. The data include indications of layered peaks of several volts per meter in the mesospheric field at high and low latitudes in situations of relatively low conductivity. During an auroral 'REP' event the electric field reversed direction in the lower stratosphere, accompanied by a substantial enhancement in conductivity. The data generally do not confirm speculations based only on the extension of the thunderstorm circuit from below or the mapping of ionospheric and magnetospheric fields from above, but seem to require, in addition, internal generation processes in the middle atmosphere.

  20. Ocular accommodation and cognitive demand: An additional indicator besides pupil size and cardiovascular measures?

    PubMed Central

    Jainta, Stephanie; Hoormann, Joerg; Jaschinski, Wolfgang

    2008-01-01

    Background The aim of the present study was to assess accommodation as a possible indicator of changes in the autonomic balance caused by altered cognitive demand. Accounting for accommodative responses from a human factors perspective may be motivated by the interest of designing virtual image displays or by establishing an autonomic indicator that allows for remote measurement at the human eye. Heart period, pulse transit time, and the pupillary response were considered as reference for possible closed-loop accommodative effects. Cognitive demand was varied by presenting monocularly numbers at a viewing distance of 5 D (20 cm) which had to be read, added or multiplied; further, letters were presented in a "n-back" task. Results Cardiovascular parameters and pupil size indicated a change in autonomic balance, while error rates and reaction time confirmed the increased cognitive demand during task processing. An observed decrease in accommodation could not be attributed to the cognitive demand itself for two reasons: (1) the cognitive demand induced a shift in gaze direction which, for methodological reasons, accounted for a substantial part of the observed accommodative changes. (2) Remaining effects disappeared when the correctness of task processing was taken into account. Conclusion Although the expectation of accommodation as possible autonomic indicator of cognitive demand was not confirmed, the present results are informative for the field of applied psychophysiology noting that it seems not to be worthwhile to include closed-loop accommodation in future studies. From a human factors perspective, expected changes of accommodation due to cognitive demand are of minor importance for design specifications – of, for example, complex visual displays. PMID:18721478

  1. LIDAR Wind Speed Measurements of Evolving Wind Fields

    SciTech Connect

    Simley, E.; Pao, L. Y.; Kelley, N.; Jonkman, B.; Frehlich, R.

    2012-01-01

    Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems that are designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed the validity of physicist G.I. Taylor's 1938 frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations using the National Renewable Energy Laboratory's (NREL's) 5-megawatt turbine model to create a more realistic measurement model. A simple model of wind evolution was applied to a frozen wind field that was used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements were also evaluated using a large eddy simulation (LES) of a stable boundary layer that was provided by the National Center for Atmospheric Research. The LIDAR measurement scenario investigated consists of a hub-mounted LIDAR that scans a circle of points upwind of the turbine in order to estimate the wind speed component in the mean wind direction. Different combinations of the preview distance that is located upwind of the rotor and the radius of the scan circle were analyzed. It was found that the dominant source of measurement error for short preview distances is the detection of transverse and vertical wind speeds from the line-of-sight LIDAR measurement. It was discovered in previous studies that, in the absence of wind evolution, the dominant source of error for large preview distances

  2. A compact DOAS instrument optimised for ammonia field-measurements

    NASA Astrophysics Data System (ADS)

    Neftel, Albrecht; Sintermann, Joerg; Dietrich, Klaus; Häni, Christoph; Jocher, Markus

    2016-04-01

    Accurate, high time-resolution measurements of NH3 in ambient air are still a challenge due to the stickiness of this molecule and its interactions with inlet or instrument surfaces. Differential optical absorption spectroscopy (DOAS) with open-path arrangement offers a contact-free in-situ approach to determine ambient NH3. We present a DOAS instrument, optimised for open-path field-measurements of ambient ammonia (NH3) alongside nitrogen oxide (NO) and sulphur dioxide (SO2). This device, operating in the UV range over paths of up to 100 m, is a further development of the miniDOAS presented by Volten et al. (2012). We use a temperature-controlled spectrometer, a deuterium light source and a modified optical arrangement. The system was set up in a robust, field-deployable, temperature-regulated housing. For the evaluation of light spectra a new high-pass filter routine based upon robust baseline extraction with local regression was used. In order to fit differential absorption cross-sections to the measurements, multiple linear regression is performed including terms of an autoregressive-moving-average model. In this presentation we discuss the influence of filter and fit procedure on the precision and accuracy of the system with examples of field measurements with artificial NH3 sources. Volten, H., Bergwerff, J. B., Haaima, M., Lolkema, D. E., Berkhout, A. J. C., van der Hoff, G. R., Potma, C. J. M., Wichink Kruit, R. J., van Pul, W. A. J. and Swart, D. P. J.: Two instruments based on differential optical absorption spectroscopy (DOAS) to measure accurate ammonia concentrations in the atmosphere, Atmospheric Meas. Tech., 5(2), 413-427, doi:10.5194/amt-5-413-2012, 2012.

  3. Field Testing of a Wet FGD Additive for Enhanced Mercury Control - Task 3 Full-scale Test Results

    SciTech Connect

    Gary Blythe

    2007-05-01

    This Topical Report summarizes progress on Cooperative Agreement DE-FC26-04NT42309, 'Field Testing of a Wet FGD Additive'. The objective of the project is to demonstrate the use of a flue gas desulfurization (FGD) additive, Degussa Corporation's TMT-15, to prevent the reemission of elemental mercury (Hg{sup 0}) in flue gas exiting wet FGD systems on coal-fired boilers. Furthermore, the project intends to demonstrate whether the additive can be used to precipitate most of the mercury (Hg) removed in the wet FGD system as a fine TMT salt that can be separated from the FGD liquor and bulk solid byproducts for separate disposal. The project is conducting pilot- and full-scale tests of the TMT-15 additive in wet FGD absorbers. The tests are intended to determine required additive dosages to prevent Hg{sup 0} reemissions and to separate mercury from the normal FGD byproducts for three coal types: Texas lignite/Power River Basin (PRB) coal blend, high-sulfur Eastern bituminous coal, and low-sulfur Eastern bituminous coal. The project team consists of URS Group, Inc., EPRI, TXU Generation Company LP, Southern Company, and Degussa Corporation. TXU Generation has provided the Texas lignite/PRB cofired test site for pilot FGD tests, Monticello Steam Electric Station Unit 3. Southern Company is providing the low-sulfur Eastern bituminous coal host site for wet scrubbing tests, as well as the pilot- and full-scale jet bubbling reactor (JBR) FGD systems to be tested. IPL, an AES company, provided the high-sulfur Eastern bituminous coal full-scale FGD test site and cost sharing. Degussa Corporation is providing the TMT-15 additive and technical support to the test program as cost sharing. The project is being conducted in six tasks. Of the six project tasks, Task 1 involves project planning and Task 6 involves management and reporting. The other four tasks involve field testing on FGD systems, either at pilot or full scale. The four tasks include: Task 2 - Pilot Additive Testing

  4. Modeling and Measurement of Ocean Generated Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Liang, R.; Avera, W. E.; Nelson, J.; Brozena, J. M.

    2011-12-01

    Motion of conductive seawater through the earth's magnetic field will produce magnetic fields. Magnetic fields from motions such as ocean waves and swells are detectable near the ocean's surface but decay rapidly with distance. Non-linear internal waves (NLIWs) generated by mechanisms such as tides over bathymetric features have been predicted to produce magnetic anomalies of .1-1 nT at altitudes of ~ 100 m above the surface (Chave, 1986) due to the large volumes of coherently moving water. An experiment was performed in 2009 by the Defense Research and Development Canada (DRDC) and the US Naval Research Laboratory (NRL) to see if magnetic signatures predicted from oceanographic measurements could be detected by airborne and ocean bottom mounted magnetometers. The test was conducted near the shelf-break off the coast of New Jersey where NLIWs have been observed. Oceanographic measurements were collected by a set of bottom-mounted ADCPs, towed C-T sensors mounted on a "SCANFISH" tow-body, and a hull-mounted ADCP. Magnetic measurements consisted of total-field magnetometers co-located with the bottom mounted ADCPs, three magnetic base-stations (total field and vector) in New Jersey for geomagnetic noise cancellation, and magnetometers aboard two aircraft ( a Canadian National Research Council Convair 580 and the NRL P-3) flown simultaneously with a 20-30 second separation ( corresponding to 2-3 km) along a repeat track over the bottom-mounted sensors. The multiple aircraft and repeat tracks were intended to remove the spatially stationary geologic component. The time-varying geomagnetic signal was extrapolated from the magnetic base-stations to the aircraft measurements. Both aircraft had high quality magnetometers and magnetic-field compensation systems based on co-located vector magnetometers and kinematic GPS. The Convair had two magnetometer and compensation systems mounted in wing-pods with a base-line of ~ 32 m that allowed the calculation of a cross

  5. Sampling the sound field in auditoria using large natural-scale array measurements.

    PubMed

    Witew, Ingo B; Vorländer, Michael; Xiang, Ning

    2017-03-01

    Suitable data for spatial wave field analyses in concert halls need to satisfy the sampling theorem and hence requires densely spaced measurement positions over extended regions. The described measurement apparatus is capable of automatically sampling the sound field in auditoria over a surface of 5.30 m × 8.00 m to any appointed resolutions. In addition to discussing design features, a case study based on measured impulse responses is presented. The experimental data allow wave field animations demonstrating how sound propagating at grazing incidence over theater seating is scattered from rows of chairs (seat-dip effect). The visualized data of reflections and scattering from an auditorium's boundaries give insights and opportunities for advanced analyses.

  6. Plasma and electric field measurements of the PVO in the Venus ionosheath. [Pioneer Venus Orbiter

    NASA Technical Reports Server (NTRS)

    Perez-De-tejada, H.; Intriligator, D. S.; Scarf, F. L.

    1984-01-01

    A study of the plasma and electric-field measurements of the PVO in the Venus ionosheath near the terminator region is presented. A drastic decrease of the particle-flux intensity measured with the plasma instrument is encountered in the inner ionosheath before the inbound crossing of the ionopause. The outer boundary of the region of weak plasma fluxes is consistent with the presence of a rarefaction wave as reported previously from the Mariner 5 (Bridge et at., 1967), Venera (Verigin et al., 1978) and PVO (Spenner et al., 1980) plasma measurements in the Venus wake. Near that boundary there are, in addition, appreciable changes in the electric field signals detected with the PVO electric-field detectors. These observations suggest the existence of local plasma-wave activity associated with turbulent flow conditions in that region.

  7. Measurement of Radiation - Light Field Congruence using a Photodiode Array

    NASA Astrophysics Data System (ADS)

    Balderson, Michael J.

    Improved treatment techniques in radiation therapy provide incentive to reduce treatment margins, thereby increasing the necessity for more accurate geometrical setup of the linear accelerator and accompanying components. In this thesis, we describe the development of a novel device that enables precise and automated measurement of radiation-light field congruence of medical linear accelerators for the purpose of improving setup accuracy, and standardizing repeated quality control activities. The device consists of a silicon photodiode array, an evaluation board, a data acquisition card, and a laptop. Using the device, we show that the radiation-light field congruence for both 6 and 15 MV beams is within 2 mm on a Varian Clinac 21 EX medical linear accelerator. Because measurements are automated, ambiguities resulting from observer variability are removed, greatly improving the reproducibility of measurements over time and across observers. We expect the device to be useful in providing consistent measurements on linear accelerators used for stereotactic radiosurgery, during the commissioning of new linear accelerators, and as an alternative to film or other commercially available devices for performing monthly or annual quality control checks.

  8. A Portable, Field-Deployable Analyzer for Isotopic Water Measurements

    NASA Astrophysics Data System (ADS)

    Berman, E. S.; Gupta, M.; Huang, Y. W.; Lacelle, D.; McKay, C. P.; Fortson, S.

    2015-12-01

    Water stable isotopes have for many years been used to study the hydrological cycle, catchment hydrology, and polar climate among other applications. Typically, discrete water samples are collected and transported to a laboratory for isotope analysis. Due to the expense and labor associated with such sampling, isotope studies have generally been limited in scope and time-resolution. Field sampling of water isotopes has been shown in recent years to provide dense data sets with the increased time resolution illuminating substantially greater short term variability than is generally observed during discrete sampling. A truly portable instrument also opens the possibility to utilize the instrument as a tool for identifying which water samples would be particularly interesting for further laboratory investigation. To make possible such field measurements of liquid water isotopes, Los Gatos Research has developed a miniaturized, field-deployable liquid water isotope analyzer. The prototype miniature liquid water isotope analyzer (mini-LWIA) uses LGR's patented Off-Axis ICOS (Integrated Cavity Output Spectroscopy) technology in a rugged, Pelican case housing for easy transport and field operations. The analyzer simultaneously measures both δ2H and δ18O from liquid water, with both manual and automatic water introduction options. The laboratory precision for δ2H is 0.6 ‰, and for δ18O is 0.3 ‰. The mini-LWIA was deployed in the high Arctic during the summer of 2015 at Inuvik in the Canadian Northwest Territories. Samples were collected from Sachs Harbor, on the southwest coast of Banks Island, including buried basal ice from the Lurentide Ice Sheet, some ice wedges, and other types of ground ice. Methodology and water analysis results from this extreme field deployment will be presented.

  9. Temperature and Magnetic Field Dependence of Critical Current Density of YBCO with Varying Flux Pinning Additions (POSTPRINT)

    DTIC Science & Technology

    2010-03-01

    coverage corresponding to M phase 1 nm thickness was found to be necessary to increase compared to YBCO . The op- timal layer thickness for each M phase was...kept constant in this experiment: , Y211 0.8 nm , and [17]. Using the optimal M phase thickness, the YBCO layer was also systematically varied for...AFRL-RZ-WP-TP-2010-2083 TEMPERATURE AND MAGNETIC FIELD DEPENDENCE OF CRITICAL CURRENT DENSITY OF YBCO WITH VARYING FLUX PINNING ADDITIONS

  10. Full field imaging based instantaneous hyperspectral absolute refractive index measurement

    SciTech Connect

    Baba, Justin S; Boudreaux, Philip R

    2012-01-01

    Multispectral refractometers typically measure refractive index (RI) at discrete monochromatic wavelengths via a serial process. We report on the demonstration of a white light full field imaging based refractometer capable of instantaneous multispectral measurement of absolute RI of clear liquid/gel samples across the entire visible light spectrum. The broad optical bandwidth refractometer is capable of hyperspectral measurement of RI in the range 1.30 1.70 between 400nm 700nm with a maximum error of 0.0036 units (0.24% of actual) at 414nm for a = 1.50 sample. We present system design and calibration method details as well as results from a system validation sample.

  11. Electric fields and neutral winds from monostatic incoherent scatter measurements by means of stochastic inversion

    NASA Astrophysics Data System (ADS)

    Nygrén, T.; Aikio, A. T.; Kuula, R.; Voiculescu, M.

    2011-05-01

    A new method utilizing stochastic inversion in determining the electric field and neutral wind from monostatic beam swing incoherent scatter measurements is described. The method consists of two stages. In the first stage, beam-aligned ion velocities from a chosen F region height interval and a set of subsequent beam directions are taken as measurements. The unknowns are the two electric field components and the field-aligned ion velocity profile. The solution gives the most probable values of the unknowns with error estimates. In the second stage, the measurements consist of beam-aligned ion velocities from the E region, and the electric fields given by the first inversion problem are also used as measurements. The number of applied beam directions may be greater than in the first inversion problem. This is a feasible approach since the neutral wind usually changes more slowly than the electric field. The solution of the second inversion problem gives the most probable values of the three neutral wind components. Results of the method are shown for 11 September 2005, when the European Incoherent Scatter (EISCAT) UHF radar was running in the CP2 experiment mode, which is a four-position 6 min monostatic cycle. In addition, from each beam direction a tristatic measurement at one F region range gate was made using two additional receivers. That allowed comparison between the monostatic and tristatic electric field results, which were in excellent agreement. The calculated neutral wind components were in good accordance with previous measurements during disturbed conditions from the same site.

  12. Comparison of measured Varian Clinac 21EX and TrueBeam accelerator electron field characteristics.

    PubMed

    Lloyd, Samantha A M; Zavgorodni, Sergei; Gagne, Isabelle M

    2015-07-08

    Dosimetric comparisons of radiation fields produced by Varian's newest linear accelerator, the TrueBeam, with those produced by older Varian accelerators are of interest from both practical and research standpoints. While photon fields have been compared in the literature, similar comparisons of electron fields have not yet been reported. In this work, electron fields produced by the TrueBeam are compared with those produced by Varian's Clinac 21EX accelerator. Diode measurements were taken of fields shaped with electron applicators and delivered at 100 cm SSD, as well as those shaped with photon MLCs without applicators and delivered at 70 cm SSD for field sizes ranging from 5 × 5 to 25 × 25 cm² at energies between 6 and 20 MeV. Additionally, EBT2 and EBT3 radio-chromic film measurements were taken of an MLC-shaped aperture with closed leaf pairs delivered at 70 cm SSD using 6 and 20 MeV electrons. The 6 MeV fields produced by the TrueBeam and Clinac 21EX were found to be almost indistinguishable. At higher energies, TrueBeam fields shaped by electron applicators were generally flatter and had less photon contamination compared to the Clinac 21EX. Differences in PDDs and profiles fell within 3% and 3 mm for the majority of measurements. The most notable differences for open fields occurred in the profile shoulders for the largest applicator field sizes. In these cases, the TrueBeam and Clinac 21EX data differed by as much as 8%. Our data indicate that an accurate electron beam model of the Clinac 21EX could be used as a starting point to simulate electron fields that are dosimetrically equivalent to those produced by the TrueBeam. Given that the Clinac 21EX shares head geometry with Varian's iX, Trilogy, and Novalis TX accelerators, our findings should also be applicable to these machines.

  13. Turbulence Measurements in the Near Field of a Wingtip Vortex

    NASA Technical Reports Server (NTRS)

    Chow, Jim; Zilliac, Greg; Bradshaw, Peter

    1997-01-01

    The roll-up of a wingtip vortex, at Reynolds number based on chord of 4.6 million was studied with an emphasis on suction side and near wake measurements. The research was conducted in a 32 in. x 48 in. low-speed wind tunnel. The half-wing model had a semi-span of 36 in. a chord of 48 in. and a rounded tip. Seven-hole pressure probe measurements of the velocity field surrounding the wingtip showed that a large axial velocity of up to 1.77 U(sub infinity) developed in the vortex core. This level of axial velocity has not been previously measured. Triple-wire probes have been used to measure all components of the Reynolds stress tensor. It was determined from correlation measurements that meandering of the vortex was small and did not appreciably contribute to the turbulence measurements. The flow was found to be turbulent in the near-field (as high as 24 percent RMS w - velocity on the edge of the core) and the turbulence decayed quickly with streamwise distance because of the nearly solid body rotation of the vortex core mean flow. A streamwise variation of the location of peak levels of turbulence, relative to the core centerline, was also found. Close to the trailing edge of the wing, the peak shear stress levels were found at the edge of the vortex core, whereas in the most downstream wake planes they occurred at a radius roughly equal to one-third of the vortex core radius. The Reynolds shear stresses were not aligned with the mean strain rate, indicating that an isotropic-eddy-viscosity based prediction method cannot accurately model the turbulence in the cortex. In cylindrical coordinates, with the origin at the vortex centerline, the radial normal stress was found to be larger than the circumferential.

  14. Lorentz force electrical impedance tomography using magnetic field measurements.

    PubMed

    Zengin, Reyhan; Gençer, Nevzat Güneri

    2016-08-21

    In this study, magnetic field measurement technique is investigated to image the electrical conductivity properties of biological tissues using Lorentz forces. This technique is based on electrical current induction using ultrasound together with an applied static magnetic field. The magnetic field intensity generated due to induced currents is measured using two coil configurations, namely, a rectangular loop coil and a novel xy coil pair. A time-varying voltage is picked-up and recorded while the acoustic wave propagates along its path. The forward problem of this imaging modality is defined as calculation of the pick-up voltages due to a given acoustic excitation and known body properties. Firstly, the feasibility of the proposed technique is investigated analytically. The basic field equations governing the behaviour of time-varying electromagnetic fields are presented. Secondly, the general formulation of the partial differential equations for the scalar and magnetic vector potentials are derived. To investigate the feasibility of this technique, numerical studies are conducted using a finite element method based software. To sense the pick-up voltages a novel coil configuration (xy coil pairs) is proposed. Two-dimensional numerical geometry with a 16-element linear phased array (LPA) ultrasonic transducer (1 MHz) and a conductive body (breast fat) with five tumorous tissues is modeled. The static magnetic field is assumed to be 4 Tesla. To understand the performance of the imaging system, the sensitivity matrix is analyzed. The sensitivity matrix is obtained for two different locations of LPA transducer with eleven steering angles from [Formula: see text] to [Formula: see text] at intervals of [Formula: see text]. The characteristics of the imaging system are shown with the singular value decomposition (SVD) of the sensitivity matrix. The images are reconstructed with the truncated SVD algorithm. The signal-to-noise ratio in measurements is assumed 80 d

  15. Lorentz force electrical impedance tomography using magnetic field measurements

    NASA Astrophysics Data System (ADS)

    Zengin, Reyhan; Güneri Gençer, Nevzat

    2016-08-01

    In this study, magnetic field measurement technique is investigated to image the electrical conductivity properties of biological tissues using Lorentz forces. This technique is based on electrical current induction using ultrasound together with an applied static magnetic field. The magnetic field intensity generated due to induced currents is measured using two coil configurations, namely, a rectangular loop coil and a novel xy coil pair. A time-varying voltage is picked-up and recorded while the acoustic wave propagates along its path. The forward problem of this imaging modality is defined as calculation of the pick-up voltages due to a given acoustic excitation and known body properties. Firstly, the feasibility of the proposed technique is investigated analytically. The basic field equations governing the behaviour of time-varying electromagnetic fields are presented. Secondly, the general formulation of the partial differential equations for the scalar and magnetic vector potentials are derived. To investigate the feasibility of this technique, numerical studies are conducted using a finite element method based software. To sense the pick-up voltages a novel coil configuration (xy coil pairs) is proposed. Two-dimensional numerical geometry with a 16-element linear phased array (LPA) ultrasonic transducer (1 MHz) and a conductive body (breast fat) with five tumorous tissues is modeled. The static magnetic field is assumed to be 4 Tesla. To understand the performance of the imaging system, the sensitivity matrix is analyzed. The sensitivity matrix is obtained for two different locations of LPA transducer with eleven steering angles from -{{25}\\circ} to {{25}\\circ} at intervals of {{5}\\circ} . The characteristics of the imaging system are shown with the singular value decomposition (SVD) of the sensitivity matrix. The images are reconstructed with the truncated SVD algorithm. The signal-to-noise ratio in measurements is assumed 80 dB. Simulation studies

  16. A magnetic field measurement technique using a miniature transducer

    NASA Technical Reports Server (NTRS)

    Fales, C. L., Jr.; Breckenridge, R. A.; Debnam, W. J., Jr.

    1974-01-01

    The development, fabrication, and application of a magnetometer are described. The magnetometer has a miniature transducer and is capable of automatic scanning. The magnetometer described here is capable of detecting static magnetic fields as low as 1.6 A/m and its transducer has an active area 0.64 mm by 0.76 mm. Thin and rugged, the transducer uses wire, 0.05 mm in diameter, which is plated with a magnetic film, enabling measurement of transverse magnetic fields as close as 0.08 mm from a surface. The magnetometer, which is simple to operate and has a fast response, uses an inexpensive clip-on milliammeter (commonly found in most laboratories) for driving and processing the electrical signals and readout. A specially designed transducer holding mechanism replaces the XY recorder ink pen; this mechanism provides the basis for an automatic scanning technique. The instrument has been applied to the measurements of magnetic fields arising from remanent magnetization in experimental plated-wire memory planes and regions of magnetic activity in geological rock specimens.

  17. Modelling Electrostatic Sheath Effects on Swarm Electric Field Instrument Measurements

    NASA Astrophysics Data System (ADS)

    Marchand, R.; Burchill, J. K.; Knudsen, D. J.

    2010-10-01

    The Electric Field Instrument (EFI) was designed to measure ionospheric ion flow velocities, temperatures and distribution functions at the ram face of the European Space Agency’s Swarm spacecraft. These flow velocities, combined with the known orbital velocity of the satellite and local magnetic field, will be used to infer local electric fields from the relation E=- v× B. EFI is among a class of many particle sensors and flow meters mounted on satellites to monitor in situ plasma conditions. The interpretation of the measurements made with EFI and similar sensors relies on a spacecraft sheath model. A common approach, valid in the relatively cold and dense ionospheric plasma, is to assume a potential drop in a thin sheath through which particle deflection and energisation can be calculated analytically. In such models, sheath effects only depend on the spacecraft floating potential, and on the angle of incidence of particles with respect to the normal to the surface. Corrections to measurements are therefore local as they do not depend on the geometry of nearby objects. In an actual plasma, satellites are surrounded by electrostatic sheaths with a finite thickness. As a result, local corrections to particle distribution functions can only be seen as an approximation. A correct interpretation of measured particle fluxes or particle distribution functions must, at least in principle, account for the extent and shape of the sheath in the vicinity of the measuring instrument. This in turn requires a careful analysis of the interaction of the satellite with the surrounding plasma, while accounting for detailed aspects of the geometry, as well as for several physical effects. In this paper, the validity of the thin sheath model is tested by comparing its predictions with detailed PIC (Particle In Cell) calculations of satellite-plasma interaction. Deviations attributed to sheath finite thickness effects are calculated for EFI measurements, with representative plasma

  18. 49 CFR 192.935 - What additional preventive and mitigative measures must an operator take?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... STANDARDS Gas Transmission Pipeline Integrity Management § 192.935 What additional preventive and mitigative... detection systems, replacing pipe segments with pipe of heavier wall thickness, providing additional... supervision of known excavation work. (ii) Collecting in a central database information that is...

  19. An electrical conductivity method for measuring the effects of additives on effective diffusivities in Portland cement pastes

    SciTech Connect

    Kyi, A.A. ); Batchelor, B. . Civil Engineering)

    1994-01-01

    Effective diffusivities are important in describing corrosion and leaching of contaminants in cementitious systems. An electrical conductivity procedure has been used to measure the effective diffusivities of compounds in cementitious systems containing the additives fly ash, silica fume, sodium silicate and bentonite. Silica fume was the most effective additive in reducing the effective diffusivity, but fly ash was the most cost effective. Diffusivities that have been measured with techniques that rely on flux of a compound through the solid were generally lower than those measured with the electrical conductivity procedure. Porosity and bulk density are not well correlated with effective diffusivity in systems containing additives.

  20. REVIEW OF HIGH FIELD Q SLOPE, CAVITY MEASUREMENTS

    SciTech Connect

    Gianluigi Ciovati

    2008-01-23

    One of the most interesting phenomenon occurring in superconducting radio-frequency (SRF) cavities made of bulk niobium is represented by a sharp decrease of the quality factor above peak surface magnetic field of about 90 mT and is referred to as "high field Q-slope" or "Q-drop". This phenomenon was observed first in 1997 and since then some effort was devoted to the understanding of the causes behind it. Still, no clear physical interpretation of the Q-drop has emerged, despite several attempts. In this contribution, I will review the experimental results for various cavities measured in many laboratories and I will try to identify common features and differences related to the Q-drop.

  1. Measurements of the E region neutral wind field

    NASA Technical Reports Server (NTRS)

    Cogger, L. L.; Murphree, J. S.; Tepley, C. A.; Meriwether, J. W., Jr.

    1985-01-01

    The neutral E-region wind field was measured at Calgary, Canada (51 N, 114 N) during 75 nights in 1982. Observations of the Doppler shift of the 5577-A emission line of atomic oxygen using a Fabry-Perot interferometer were converted to horizontal wind vectors. From the analysis of the data, four categories of wind characteristics were identified. In order of increasing magnetic activity these categories are: (1) wind field mostly variable in space and time; (2) predominantly equatorward flow throughout the night, (3) predominantly poleward flow throughout the night and (4) north-westward flow before midnight and southward after midnight. The wind magnitude was also variable and on some disturbed days exceeded 200 m/s.

  2. Nonlinear propagation in ultrasonic fields: measurements, modelling and harmonic imaging.

    PubMed

    Humphrey, V F

    2000-03-01

    In high amplitude ultrasonic fields, such as those used in medical ultrasound, nonlinear propagation can result in waveform distortion and the generation of harmonics of the initial frequency. In the nearfield of a transducer this process is complicated by diffraction effects associated with the source. The results of a programme to study the nonlinear propagation in the fields of circular, focused and rectangular transducers are described, and comparisons made with numerical predictions obtained using a finite difference solution to the Khokhlov-Zabolotskaya-Kuznetsov (or KZK) equation. These results are extended to consider nonlinear propagation in tissue-like media and the implications for ultrasonic measurements and ultrasonic heating are discussed. The narrower beamwidths and reduced side-lobe levels of the harmonic beams are illustrated and the use of harmonics to form diagnostic images with improved resolution is described.

  3. Magsat vector magnetometer calibration using Magsat geomagnetic field measurements

    NASA Technical Reports Server (NTRS)

    Lancaster, E. R.; Jennings, T.; Morrissey, M.; Langel, R. A.

    1980-01-01

    From the time of its launch on Oct. 30, 1979 into a nearly polar, Sun synchronous orbit, until it reentered the Earth's atmosphere on June 11, 1980, Magsat measured and transmitted more than three complete sets of global magnetic field data. The data obtained from the mission will be used primarily to compute a currently accurate model of the Earth's main magnetic field, to update and refine world and regional magnetic charts, and to develop a global scalar and vector crustal magnetic anomaly map. The in-flight calibration procecure used for 39 vector magnetometer system parameters is described as well as results obtained from some data sets and the numerical studies designed to evaluate the results.

  4. 75 FR 73090 - Medicare Program; Listening Session on Development of Additional Imaging Efficiency Measures for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-29

    ..., cell phones, and palm pilots, are subject to physical inspection. We cannot assume responsibility for... measures that CMS could consider. Measure developers, hospitals, medical specialty societies, medical... medical technology costs. The imaging efficiency measures fill a significant gap in the availability...

  5. Geotechnical field measurements: G-tunnel, Nevada test site

    NASA Astrophysics Data System (ADS)

    Zimmerman, R. M.; Vollendorf, W. C.

    1982-05-01

    The FY81 geotechnical measurements focused on borehole measurements in the Grouse Canyon welded tuff in G-tunnel on the Nevada Test Site. These ambient temperature measures were taken to: (1) establish baseline reference field data, and (2) gain field testing experience in welded tuff. The in situ state of stress was obtained using the three-hole overcoring method with the US Bureau of Mines three-component borehole deformation gage. The orthogonal horizontal stresses were 5.5 and 0.3 MPa and the nominal vertical was 8.5. Biaxial tests were performed on recovered cores and the average modulus of deformation was 31 GPa. The modulus of deformation using the borehole jack (Goodman) had an average value of 12 GPa. This value is not corrected for effective bearing contact area. Two orthogonal boreholes were used to determine the range of hydraulic conductivities. The range was from 0.022 cm/s (22 Darcy's) to 1.923 cm/s (1988 Dracy's).

  6. Geotechnical field measurements: G-tunnel, Nevada Test Site

    SciTech Connect

    Zimmerman, R.M.; Vollendorf, W.C.

    1982-05-01

    The FY81 geotechnical measurements focused on borehole measurements in the Grouse Canyon welded tuff in G-tunnel on the Nevada Test Site. These ambient temperature measurements were taken to: (1) establish baseline reference field data, and (2) gain field testing experience in welded tuff. The in situ state of stress was obtained using the three-hole overcoring method with the US Bureau of Mines three-component borehole deformation gage. The orthogonal horizontal stresses were 5.5 and 0.3 MPa and the nominal vertical was 8.5. Biaxial tests were performed on recovered cores and the average modulus of deformation was 31 GPa. The modulus of deformation using the borehole jack (Goodman) had an average value of 12 GPa. This value is not corrected for effective bearing contact area. Two orthogonal boreholes were used to determine the range of hydraulic conductivities. The range was from 0.022 cm/s (22 Darcy`s) to 1.923 cm/s (1988 Darcy`s).

  7. Boom accomodation effects on plasma and field measurements with RPWI

    NASA Astrophysics Data System (ADS)

    Cervantes Correa, P.; Eriksson, A. I.; Wahlund, J.-E.; Odelstad, E.; Vaivads, A.; Bergman, J.

    2013-09-01

    While the JUICE spacecraft configuration and main contractor are yet to be decided, it is still possible to investigate general issues on the impact of various boom accomodation alternatives for measurements of plasma and electric fields using the Langmuir probe system of the Radio and Plasma Waves Investigation. These probes can be used as classical Langmuir probes, as electric field probes, or for mutual impedance measurements, and the impact of e.g. varying illumination and wake interference are different for each type of measurement. While there is a nominal JUICE trajectory for the main science mission, we have to do assumptions on the spacecraft pointing, e.g. nadir pointing during flybys of the various moons. The detailed spacecraft layout is not known, but we can arrive at general conclusions on the suitability of various boom accomodations by assuming a cube-like spacecraft with solar panels as rectangular wings. For disturbing structures like wakes and photoelectron clouds we use simple models based on previous simulations. Even though the detailed pointing and spacecraft design will quite certainly deviate from our assumptions, and the model has uncertainties also in other respects, we can still give some general conclusions on boom accomodation alternatives.

  8. Full field gas phase velocity measurements in microgravity

    NASA Technical Reports Server (NTRS)

    Griffin, Devon W.; Yanis, William

    1995-01-01

    Measurement of full-field velocities via Particle Imaging Velocimetry (PIV) is common in research efforts involving fluid motion. While such measurements have been successfully performed in the liquid phase in a microgravity environment, gas-phase measurements have been beset by difficulties with seeding and laser strength. A synthesis of techniques developed at NASA LeRC exhibits promise in overcoming these difficulties. Typical implementation of PIV involves forming the light from a pulsed laser into a sheet that is some fraction of a millimeter thick and 50 or more millimeters wide. When a particle enters this sheet during a pulse, light scattered from the particle is recorded by a detector, which may be a film plane or a CCD array. Assuming that the particle remains within the boundaries of the sheet for the second pulse and can be distinguished from neighboring particles, comparison of the two images produces an average velocity vector for the time between the pulses. If the concentration of particles in the sampling volume is sufficiently large but the particles remain discrete, a full field map may be generated.

  9. Probe measurements of the three-dimensional magnetic field structure in a rotating magnetic field sustained field-reversed configuration

    SciTech Connect

    Velas, K. M.; Milroy, R. D.

    2014-01-15

    A translatable three-axis probe was constructed and installed on the translation, confinement, and sustainment upgrade (TCSU) experiment. With ninety windings, the probe can simultaneously measure B{sub r}, B{sub θ}, and B{sub z} at 30 radial positions, and can be placed at any desired axial position within the field reversed configuration (FRC) confinement chamber. Positioning the probe at multiple axial positions and taking multiple repeatable shots allows for a full r-z map of the magnetic field. Measurements were made for odd-parity rotating magnetic field (RMF) antennas and even-parity RMF. The steady state data from applying a 10 kHz low pass filter used in conjunction with data at the RMF frequency yields a map of the full 3D rotating field structure. Comparisons will be made to the 3D magnetic structure predicted by NIMROD simulations, with parameters adjusted to match that of the TCSU experiments. The probe provides sufficient data to utilize a Maxwell stress tensor approach to directly measure the torque applied to the FRC's electrons, which combined with a resistive torque model, yields an estimate of the average FRC resistivity.

  10. Probe measurements of the three-dimensional magnetic field structure in a rotating magnetic field sustained field-reversed configuration

    NASA Astrophysics Data System (ADS)

    Velas, K. M.; Milroy, R. D.

    2014-01-01

    A translatable three-axis probe was constructed and installed on the translation, confinement, and sustainment upgrade (TCSU) experiment. With ninety windings, the probe can simultaneously measure Br, Bθ, and Bz at 30 radial positions, and can be placed at any desired axial position within the field reversed configuration (FRC) confinement chamber. Positioning the probe at multiple axial positions and taking multiple repeatable shots allows for a full r-z map of the magnetic field. Measurements were made for odd-parity rotating magnetic field (RMF) antennas and even-parity RMF. The steady state data from applying a 10 kHz low pass filter used in conjunction with data at the RMF frequency yields a map of the full 3D rotating field structure. Comparisons will be made to the 3D magnetic structure predicted by NIMROD simulations, with parameters adjusted to match that of the TCSU experiments. The probe provides sufficient data to utilize a Maxwell stress tensor approach to directly measure the torque applied to the FRC's electrons, which combined with a resistive torque model, yields an estimate of the average FRC resistivity.

  11. Laboratory measurements on reservoir rocks from The Geysers geothermal field

    SciTech Connect

    Boitnott, G.N.

    1995-01-26

    A suite of laboratory measurements have been conducted on Geysers metagraywacke and metashale recovered from a drilled depth of 2599 to 2602 meters in NEGU-17. The tests have been designed to constrain the mechanical and water-storage properties of the matrix material. Various measurements have been made at a variety of pressures and at varying degrees of saturation. Both compressional and shear velocities exhibit relatively little change with effective confining pressure. In all of the samples, water saturation causes an increase in the compressional velocity. In some samples, saturation results in a moderate decrease in shear velocity greater in magnitude than would be expected based on the slight increase in bulk density. It is found that the effect of saturation on the velocities can be quantitatively modeled through a modification of Biot-Gassmann theory to include weakening of the shear modulus with saturation. The decrease is attributed to chemo-mechanical weakening caused by the presence of water. The degree of frame weakening of the shear modulus is variable between samples, and appears correlated with petrographic features of the cores. Two related models are presented through which we can study the importance of saturation effects on field-scale velocity variations. The model results indicate that the saturation effects within the matrix are significant and may contribute to previously observed field anomalies. The results help to define ways in which we may be able to separate the effects of variations in rock properties, caused by phenomena such as degree of fracturing, from similar effects caused by variations in matrix saturation. The need for both compressional and shear velocity data in order to interpret field anomalies is illustrated through comparisons of model results with the field observations.

  12. Field Experiment Provides Ground Truth for Surface NMR Measurement

    NASA Astrophysics Data System (ADS)

    Knight, R. J.; Abraham, J. D.; Cannia, J. C.; Dlubac, K. I.; Grau, B.; Grunewald, E. D.; Irons, T.; Song, Y.; Walsh, D.

    2010-12-01

    Effective and sustainable long-term management of fresh water resources requires accurate information about the availability of water in groundwater aquifers. Proton Nuclear Magnetic Resonance (NMR) can provide a direct link to the presence of water in the pore space of geological materials through the detection of the nuclear magnetization of the hydrogen nuclei (protons) in the pore water. Of interest for groundwater applications is the measurement of the proton-NMR relaxation time constant, referred to as T2. This parameter is sensitive to the geometry of the water-filled pore space and can be related to the hydraulic conductivity. NMR logging instruments, which have been available since the 1980’s, provide direct measurements of T2 in boreholes. Surface NMR (SNMR) is a non-invasive geophysical method that uses a loop of wire on the surface to probe the NMR properties of groundwater aquifers to a depth of ~100 m, without the need for the drilling of boreholes. SNMR provides reliable measurements of a different NMR time constant referred to as T2*, that is related to, but not necessarily equivalent to, T2. The relationship between T2* and T2 is likely to depend upon the physical environment and the composition of the sampled material. In order to advance the use of SNMR as a non-invasive means of characterizing groundwater aquifers, we must answer the fundamental question: When probing a groundwater aquifer, what information is provided by T2*, the time constant measured with SNMR? Our approach was to conduct a field experiment in Nebraska, in an area underlain by the Quaternary Alluvium and Tertiary Ogallala aquifers. We first used SNMR to obtain a 1D profile of T2* to a depth of ~60 m. We then drilled a well inside the area of the SNMR loop, to a depth of ~150 m, and used the drill cuttings to describe the composition of the geologic material at the site. The borehole was kept open for 2 days to acquire logging NMR T2 measurements over the total depth. Three

  13. The development of field-based measurement methods for radioactive fallout assessment.

    PubMed

    Miller, Kevin M; Larsen, Richard J

    2002-05-01

    An overview is provided on the development of field equipment, instrument systems, and methods of analyses that were used to assess the impact of radioactive fallout from atmospheric weapons tests. Included in this review are developments in fallout collection, aerosols measurements in surface air, and high-altitude sampling with aircraft and balloons. In addition, developments in radiation measurements are covered in such areas as survey and monitoring instruments, in situ gamma-ray spectrometry, and aerial measurement systems. The history of these developments and the interplay with the general advances in the field of radiation and radioactivity metrology are highlighted. An emphasis is given as to how the modifications and improvements in the instruments and methods over time led to their adaptation to present-day applications to radiation and radioactivity measurements.

  14. Flow field measurements in the cell culture unit.

    PubMed

    Walker, Stephen; Wilder, Mike; Dimanlig, Arsenio; Jagger, Justin; Searby, Nancy

    2002-10-01

    The cell culture unit (CCU) is being designed to support cell growth for long-duration life science experiments on the International Space Station (ISS). The CCU is a perfused loop system that provides a fluid environment for controlled cell growth experiments within cell specimen chambers (CSCs), and is intended to accommodate diverse cell specimen types. Many of the functional requirements depend on the fluid flow field within the CSC (e.g., feeding and gas management). A design goal of the CCU is to match, within experimental limits, all environmental conditions, other than the effects of gravity on the cells, whether the hardware is in microgravity ( micro g), normal Earth gravity, or up to 2g on the ISS centrifuge. In order to achieve this goal, two steps are being taken. The first step is to characterize the environmental conditions of current 1g cell biology experiments being performed in laboratories using ground-based hardware. The second step is to ensure that the design of the CCU allows the fluid flow conditions found in 1g to be replicated from microgravity up to 2g. The techniques that are being used to take these steps include flow visualization, particle image velocimetry (PIV), and computational fluid dynamics (CFD). Flow visualization using the injection of dye has been used to gain a global perspective of the characteristics of the CSC flow field. To characterize laboratory cell culture conditions, PIV is being used to determine the flow field parameters of cell suspension cultures grown in Erlenmeyer flasks on orbital shakers. These measured parameters will be compared to PIV measurements in the CSCs to ensure that the flow field that cells encounter in CSCs is within the bounds determined for typical laboratory experiments. Using CFD, a detailed simulation is being developed to predict the flow field within the CSC for a wide variety of flow conditions, including microgravity environments. Results from all these measurements and analyses of the

  15. Flow field measurements in the cell culture unit

    NASA Technical Reports Server (NTRS)

    Walker, Stephen; Wilder, Mike; Dimanlig, Arsenio; Jagger, Justin; Searby, Nancy

    2002-01-01

    The cell culture unit (CCU) is being designed to support cell growth for long-duration life science experiments on the International Space Station (ISS). The CCU is a perfused loop system that provides a fluid environment for controlled cell growth experiments within cell specimen chambers (CSCs), and is intended to accommodate diverse cell specimen types. Many of the functional requirements depend on the fluid flow field within the CSC (e.g., feeding and gas management). A design goal of the CCU is to match, within experimental limits, all environmental conditions, other than the effects of gravity on the cells, whether the hardware is in microgravity ( micro g), normal Earth gravity, or up to 2g on the ISS centrifuge. In order to achieve this goal, two steps are being taken. The first step is to characterize the environmental conditions of current 1g cell biology experiments being performed in laboratories using ground-based hardware. The second step is to ensure that the design of the CCU allows the fluid flow conditions found in 1g to be replicated from microgravity up to 2g. The techniques that are being used to take these steps include flow visualization, particle image velocimetry (PIV), and computational fluid dynamics (CFD). Flow visualization using the injection of dye has been used to gain a global perspective of the characteristics of the CSC flow field. To characterize laboratory cell culture conditions, PIV is being used to determine the flow field parameters of cell suspension cultures grown in Erlenmeyer flasks on orbital shakers. These measured parameters will be compared to PIV measurements in the CSCs to ensure that the flow field that cells encounter in CSCs is within the bounds determined for typical laboratory experiments. Using CFD, a detailed simulation is being developed to predict the flow field within the CSC for a wide variety of flow conditions, including microgravity environments. Results from all these measurements and analyses of the

  16. Novel Techniques for Pulsed Field Gradient NMR Measurements

    NASA Astrophysics Data System (ADS)

    Brey, William Wallace

    Pulsed field gradient (PFG) techniques now find application in multiple quantum filtering and diffusion experiments as well as in magnetic resonance imaging and spatially selective spectroscopy. Conventionally, the gradient fields are produced by azimuthal and longitudinal currents on the surfaces of one or two cylinders. Using a series of planar units consisting of azimuthal and radial current elements spaced along the longitudinal axis, we have designed gradient coils having linear regions that extend axially nearly to the ends of the coil and to more than 80% of the inner radius. These designs locate the current return paths on a concentric cylinder, so the coils are called Concentric Return Path (CRP) coils. Coils having extended linear regions can be made smaller for a given sample size. Among the advantages that can accrue from using smaller coils are improved gradient strength and switching time, reduced eddy currents in the absence of shielding, and improved use of bore space. We used an approximation technique to predict the remaining eddy currents and a time-domain model of coil performance to simulate the electrical performance of the CRP coil and several reduced volume coils of more conventional design. One of the conventional coils was designed based on the time-domain performance model. A single-point acquisition technique was developed to measure the remaining eddy currents of the reduced volume coils. Adaptive sampling increases the dynamic range of the measurement. Measuring only the center of the stimulated echo removes chemical shift and B_0 inhomogeneity effects. The technique was also used to design an inverse filter to remove the eddy current effects in a larger coil set. We added pulsed field gradient and imaging capability to a 7 T commercial spectrometer to perform neuroscience and embryology research and used it in preliminary studies of binary liquid mixtures separating near a critical point. These techniques and coil designs will find

  17. A miniDOAS instrument optimised for ammonia field measurements

    NASA Astrophysics Data System (ADS)

    Sintermann, Jörg; Dietrich, Klaus; Häni, Christoph; Bell, Michael; Jocher, Markus; Neftel, Albrecht

    2016-06-01

    We present a differential optical absorption spectroscopy (DOAS) instrument, called "miniDOAS", optimised for optical open-path field-measurements of ambient ammonia (NH3) alongside nitrogen oxide (NO) and sulfur dioxide (SO2). The instrument is a further development of the miniDOAS presented by Volten et al. (2012). We use a temperature-controlled spectrometer, a deuterium light source and a modified optical arrangement. The system was set up in a robust, field-deployable, temperature-regulated housing. For the evaluation of light spectra we use a new high-pass filter routine based upon robust baseline extraction with local regression. Multiple linear regression including terms of an autoregressive-moving-average model is used to determine concentrations. For NH3 the random uncertainty is about 1.4 % of the concentration, and not better than 0.2 µg m-3. Potential biases for the slope of the calibration are given by the precision of the differential absorption cross sections (±3 %) and for the offset by the precision of the estimation of concentration offsets (cref) introduced by the reference spectrum Iref. Comparisons of miniDOAS measurements to those by NH3 acid trap devices showed good agreement. The miniDOAS can be flexibly used for a wide range of field trials, such as micrometeorological NH3 flux measurements with approaches based upon horizontal or vertical concentration differences. Results from such applications covering concentration dynamics of less than one up to several hundreds of µg m-3 are presented.

  18. Field inter-comparison of eleven atmospheric ammonia measurement techniques

    NASA Astrophysics Data System (ADS)

    von Bobrutzki, K.; Braban, C. F.; Famulari, D.; Jones, S. K.; Blackall, T.; Smith, T. E. L.; Blom, M.; Coe, H.; Gallagher, M.; Ghalaieny, M.; McGillen, M. R.; Percival, C. J.; Whitehead, J. D.; Ellis, R.; Murphy, J.; Mohacsi, A.; Pogany, A.; Junninen, H.; Rantanen, S.; Sutton, M. A.; Nemitz, E.

    2010-01-01

    Eleven instruments for the measurement of ambient concentrations of atmospheric ammonia gas (NH3), based on eight different measurement methods were inter-compared above an intensively managed agricultural field in late summer 2008 in Southern Scotland. To test the instruments over a wide range of concentrations, the field was fertilised with urea midway through the experiment, leading to an increase in the average concentration from 10 to 100 ppbv. The instruments deployed included three wet-chemistry systems, one with offline analysis (annular rotating batch denuder, RBD) and two with online-analysis (Annular Denuder sampling with online Analysis, AMANDA; AiRRmonia), two Quantum Cascade Laser Absorption Spectrometers (a large-cell dual system; DUAL-QCLAS, and a compact system; c-QCLAS), two photo-acoustic spectrometers (WaSul-Flux; Nitrolux-100), a Cavity Ring Down Spectrosmeter (CRDS), a Chemical Ionisation Mass Spectrometer (CIMS), an ion mobility spectrometer (IMS) and an Open-Path Fourier Transform Infra-Red (OP-FTIR) Spectrometer. The instruments were compared with each other and with the average concentration of all instruments. An overall good agreement of hourly average concentrations between the instruments (R2>0.84), was observed for NH3 concentrations at the field of up to 120 ppbv with the slopes against the average ranging from 0.67 (DUAL-QCLAS) to 1.13 (AiRRmonia) with intercepts of -0.74 ppbv (RBD) to +2.69 ppbv (CIMS). More variability was found for performance for lower concentrations (<10 ppbv). Here the main factors affecting measurement precision are (a) the inlet design, (b) the state of inlet filters (where applicable), and (c) the quality of gas-phase standards (where applicable). By reference to the fast (1 Hz) instruments deployed during the study, it was possible to characterize the response times of the slower instruments.

  19. Field inter-comparison of eleven atmospheric ammonia measurement techniques

    NASA Astrophysics Data System (ADS)

    von Bobrutzki, K.; Braban, C. F.; Famulari, D.; Jones, S. K.; Blackall, T.; Smith, T. E. L.; Blom, M.; Coe, H.; Gallagher, M.; Ghalaieny, M.; McGillen, M. R.; Percival, C. J.; Whitehead, J. D.; Ellis, R.; Murphy, J.; Mohacsi, A.; Junninen, H.; Pogany, A.; Rantanen, S.; Sutton, M. A.; Nemitz, E.

    2009-08-01

    Eleven instruments for the measurement of ambient concentrations of atmospheric ammonia gas (NH3), based on eight different measurement methods were inter-compared above an intensively managed agricultural field in late summer 2008 in S. Scotland. To test the instruments over a wide range of concentrations, the field was fertilised with urea midway through the experiment, leading to an increase in the average concentration from 10 to 100 ppbv. The instruments deployed included three wet-chemistry systems, one with offline analysis (annular rotating batch denuder, RBD) and two with online-analysis (Annular Denuder sampling with online Analysis, AMANDA; AiRRmonia), two Quantum Cascade Laser Absorption Spectrometers (a large-cell dual system, DUAL-QCLAS, and a compact system, c-QCLAS), two photo-acoustic spectrometers (WaSul-Flux, Nitrolux-100), a Cavity Ring Down Spectrosmeter (CRDS), a Chemical Ionisation Mass Spectrometer (CIMS), an ion mobility spectrometer (IMS) and an Open-Path Fourier Transform Infra-Red (OP-FTIR) spectroscopy. Each instrument was compared with each other and with the average concentration of all instruments. An overall good agreement of hourly average concentrations between the instruments (R2>0.84), was observed for NH3 concentrations at the field of up to 120 ppbv with the slopes against the average ranging from 0.67 (DUAL-QCLAS) to 1.13 (AiRRmonia) with intercepts of -0.74 ppbv (RBD) to +2.69 ppbv (CIMS). More variability was found for performance for lower concentrations (<10 ppbv). Here the overruling factors affecting measurement precision are (a) the inlet design, (b) the state of inlet filters (where applicable), and (c) the quality of gas-phase standards (where applicable). By reference to the fast (1 Hz) instruments deployed during the study, it was possible to characterize the response times of the slower instruments.

  20. Full-field optical coherence tomography apply in sphere measurements

    NASA Astrophysics Data System (ADS)

    Shi, Wei; Li, Weiwei; li, Juncheng; Wang, Jingyu; Wang, Jianguo

    2016-10-01

    The geometry of a spherical surface, for example that of a precision optic, is completely determined by the radius -of-curvature at one point and the deviation from the perfect spherical form at all other points of the sphere. Full-field Optical Coherence Tomography (FF-OCT) is a parallel detection OCT technique that utilizes a 2D detector array. This technique avoids mechanical scanning in imaging optics, thereby speeding up the imaging process and enhancing the quality of images. The current paper presents an FF-OCT instrument that is designed to be used in sphere measurement with the principle of multiple delays (MD) OCT to evaluate the curvature and radius of curved objects in single-shot imaging. The optimum combination of the MD principle with the FF-OCT method was evaluated, and the radius of a metal ball was measured with this method. The generated 2n-1 contour lines were obtained by using an MDE with n delays in a single en-face OCT image. This method of measurement, it engaged in the measurement accuracy of spherical and enriches the means of measurement, to make a spherical scan techniques flexible application.

  1. System having unmodulated flux locked loop for measuring magnetic fields

    DOEpatents

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2006-08-15

    A system (10) for measuring magnetic fields, wherein the system (10) comprises an unmodulated or direct-feedback flux locked loop (12) connected by first and second unbalanced RF coaxial transmission lines (16a, 16b) to a superconducting quantum interference device (14). The FLL (12) operates for the most part in a room-temperature or non-cryogenic environment, while the SQUID (14) operates in a cryogenic environment, with the first and second lines (16a, 16b) extending between these two operating environments.

  2. Whole-field thickness strain measurement using multiple camera digital image correlation system

    NASA Astrophysics Data System (ADS)

    Li, Junrui; Xie, Xin; Yang, Guobiao; Zhang, Boyang; Siebert, Thorsten; Yang, Lianxiang.

    2017-03-01

    Three Dimensional digital image correlation(3D-DIC) has been widely used by industry, especially for strain measurement. The traditional 3D-DIC system can accurately obtain the whole-field 3D deformation. However, the conventional 3D-DIC system can only acquire the displacement field on a single surface, thus lacking information in the depth direction. Therefore, the strain in the thickness direction cannot be measured. In recent years, multiple camera DIC (multi-camera DIC) systems have become a new research topic, which provides much more measurement possibility compared to the conventional 3D-DIC system. In this paper, a multi-camera DIC system used to measure the whole-field thickness strain is introduced in detail. Four cameras are used in the system. two of them are placed at the front side of the object, and the other two cameras are placed at the back side. Each pair of cameras constitutes a sub stereo-vision system and measures the whole-field 3D deformation on one side of the object. A special calibration plate is used to calibrate the system, and the information from these two subsystems is linked by the calibration result. Whole-field thickness strain can be measured using the information obtained from both sides of the object. Additionally, the major and minor strain on the object surface are obtained simultaneously, and a whole-field quasi 3D strain history is acquired. The theory derivation for the system, experimental process, and application of determining the thinning strain limit based on the obtained whole-field thickness strain history are introduced in detail.

  3. Experimental Measurement of the Flow Field of Heavy Trucks

    SciTech Connect

    Fred Browand; Charles Radovich

    2005-05-31

    Flat flaps that enclose the trailer base on the sides and top are known to reduce truck drag and reduce fuel consumption. Such flapped-truck geometries have been studied in laboratory wind tunnels and in field tests. A recent review of wind tunnel data for a variety of truck geometries and flow Reynolds numbers show roughly similar values of peak drag reduction, but differ in the determination of the optimum flap angle. Optimum angles lie in the range 12 degrees-20 degrees, and may be sensitive to Reynolds number and truck geometry. The present field test is undertaken to provide additional estimates of the magnitude of the savings to be expected on a typical truck for five flap angles 10, 13, 16, 19, and 22 degrees. The flaps are constructed from a fiberglass-epoxy-matrix material and are one-quarter of the base width in length (about 61 cm, or 2 feet). They are attached along the rear door hinge lines on either side of the trailer, so that no gap appears at the joint between the flap and the side of the trailer The flap angle is adjusted by means of two aluminum supports. The present test is performed on the NASA Crows Landing Flight Facility at the northern end of the San Joaquin valley in California. The main runway is approximately 2400 meters in length, and is aligned approximately in a north-south direction The test procedure is to make a series of runs starting at either end of the runway. All runs are initiated under computer control to accelerate the truck to a target speed of 60 mph (96 6 km/hr), to proceed at the target speed for a fixed distance, and to decelerate at the far end of the runway. During a run, the broadcast fuel rate, the engine rpm, forward speed, elapsed time--as well as several other parameters (10 in all)--are digitized at a rate of 100 digitizations per second. Various flapped-conditions are interspersed with the ''no flaps'' control, and are sequenced in a different order on different days. Approximately 310 runs are accumulated

  4. 49 CFR 192.935 - What additional preventive and mitigative measures must an operator take?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... detection systems, replacing pipe segments with pipe of heavier wall thickness, providing additional training to personnel on response procedures, conducting drills with local emergency responders and... must, at least, consider the following factors—swiftness of leak detection and pipe...

  5. Lunar properties from transient and steady magnetic field measurements.

    NASA Technical Reports Server (NTRS)

    Dyal, P.; Parkin, C. W.

    1972-01-01

    The electrical conductivity of the lunar interior has been determined from magnetic field step transients measured on the lunar dark side. The simplest model which best fits the data is a spherically symmetric three layer model having a nonconducting outer crust, an intermediate layer with electrical conductivity of .00035 mhos/m, and an inner core with conductivity of .01 mhos/m. Temperatures calculated from these conductivities in the three regions for an example of an olivine moon are as follows: crust, below 440 K; intermediate layer, 890 K; and core, 1240 K. The whole-moon relative permeability has been calculated from the measurements to be 1.03 plus or minus 0.13.

  6. Reality, measurement and locality in Quantum Field Theory

    NASA Astrophysics Data System (ADS)

    Tommasini, Daniele

    2002-07-01

    It is currently believed that the local causality of Quantum Field Theory (QFT) is destroyed by the measurement process. This belief is also based on the Einstein-Podolsky-Rosen (EPR) paradox and on the so-called Bell's theorem, that are thought to prove the existence of a mysterious, instantaneous action between distant measurements. However, I have shown recently that the EPR argument is removed, in an interpretation-independent way, by taking into account the fact that the Standard Model of Particle Physics prevents the production of entangled states with a definite number of particles. This result is used here to argue in favor of a statistical interpretation of QFT and to show that it allows for a full reconciliation with locality and causality. Within such an interpretation, as Ballentine and Jarret pointed out long ago, Bell's theorem does not demonstrate any nonlocality.

  7. Field Quality Measurements in the FNAL Twin-Aperture 11 T Dipole for LHC Upgrades

    SciTech Connect

    Strauss, T.; Apollinari, G.; Apollinari, G.; Barzi, E.; Chlachidze, G.; Di Marco, J.; Nobrega, F.; Novitski, I.; Stoynev, S.; Turrioni, D.; Velev, G.; Zlobin, A. V.; Auchmann, B.; Izquierdo Bermudez, S,; Karppinen, M.; Rossi, L.; Savary, F.; Smekens, D.

    2016-11-08

    FNAL and CERN are developing an 11 T Nb3Sn dipole suitable for installation in the LHC to provide room for additional collimators. Two 1 m long collared coils previously tested at FNAL in single-aperture dipole configuration were assembled into the twin-aperture configuration and tested including magnet quench performance and field quality. The results of magnetic measurements are reported and discussed in this paper.

  8. A lithospheric magnetic field model derived from the Swarm satellite magnetic field measurements

    NASA Astrophysics Data System (ADS)

    Hulot, G.; Thebault, E.; Vigneron, P.

    2015-12-01

    The Swarm constellation of satellites was launched in November 2013 and has since then delivered high quality scalar and vector magnetic field measurements. A consortium of several research institutions was selected by the European Space Agency (ESA) to provide a number of scientific products which will be made available to the scientific community. Within this framework, specific tools were tailor-made to better extract the magnetic signal emanating from Earth's the lithospheric. These tools rely on the scalar gradient measured by the lower pair of Swarm satellites and rely on a regional modeling scheme that is more sensitive to small spatial scales and weak signals than the standard spherical harmonic modeling. In this presentation, we report on various activities related to data analysis and processing. We assess the efficiency of this dedicated chain for modeling the lithospheric magnetic field using more than one year of measurements, and finally discuss refinements that are continuously implemented in order to further improve the robustness and the spatial resolution of the lithospheric field model.

  9. Measuring Collisionless Damping in Heliospheric Plasmas using Field-Particle Correlations

    NASA Astrophysics Data System (ADS)

    Klein, K. G.; Howes, G. G.

    2016-08-01

    An innovative field-particle correlation technique is proposed that uses single-point measurements of the electromagnetic fields and particle velocity distribution functions to investigate the net transfer of energy from fields to particles associated with the collisionless damping of turbulent fluctuations in weakly collisional plasmas, such as the solar wind. In addition to providing a direct estimate of the local rate of energy transfer between fields and particles, it provides vital new information about the distribution of that energy transfer in velocity space. This velocity-space signature can potentially be used to identify the dominant collisionless mechanism responsible for the damping of turbulent fluctuations in the solar wind. The application of this novel field-particle correlation technique is illustrated using the simplified case of the Landau damping of Langmuir waves in an electrostatic 1D-1V Vlasov-Poisson plasma, showing that the procedure both estimates the local rate of energy transfer from the electrostatic field to the electrons and indicates the resonant nature of this interaction. Modifications of the technique to enable single-point spacecraft measurements of fields and particles to diagnose the collisionless damping of turbulent fluctuations in the solar wind are discussed, yielding a method with the potential to transform our ability to maximize the scientific return from current and upcoming spacecraft missions, such as the Magnetospheric Multiscale (MMS) and Solar Probe Plus missions.

  10. Coronal magnetic fields from the inversion of linear polarization measurements

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Lin, Haosheng; Kuhn, Jeff

    2010-02-01

    Real 3-D coronal magnetic field reconstruction is expected to be made based on the technologies of IR spectrometry and tomography, in which the data from other wavelengths can be used as critical reference. Our recent studies focused on this issue are briefly reviewed in this paper. Liu & Lin (2008) first evaluated the validity of potential field source surface model applied to one of five limb regions in the corona by comparing the theoretical polarization maps with SOLARC observations in the IR Fe XIII 10747 Å forbidden coronal emission line (CEL). The five limb coronal regions were then studied together in order to study the spatial relation between the bright EUV features on the solar disk and the inferred IR emission sources, which were obtained from the inversion of the SOLARC linear polarization (LP) measurements (Liu 2009). The inversion for each fiber data in the field of view was made by finding the best location where the difference between the synthesized and the observed polarizations reaches the minimum in the integration path along the line of sight. We found a close relationship between the inferred IR emission source locations and the EUV strong emission positions.

  11. Fast measurements of average flow velocity by Low-Field ¹H NMR.

    PubMed

    Osán, T M; Ollé, J M; Carpinella, M; Cerioni, L M C; Pusiol, D J; Appel, M; Freeman, J; Espejo, I

    2011-04-01

    In this paper, we describe a method for measuring the average flow velocity of a sample by means of Nuclear Magnetic Resonance. This method is based on the Carr-Purcell-Meiboom-Gill (CPMG) sequence and does not require the application of any additional static or pulsed magnetic field gradients to the background magnetic field. The technique is based on analyzing the early-time behavior of the echo amplitudes of the CPMG sequence. Measurements of average flow velocity of water are presented. The experimental results show a linear relationship between the slope/y-intercept ratio of a linear fit of the first echoes in the CPMG sequence, and the average flow velocity of the flowing fluid. The proposed method can be implemented in low-cost Low-Field NMR spectrometers allowing a continuous monitoring of the average velocity of a fluid in almost real-time, even if the flow velocity changes rapidly.

  12. A comprehensive method of estimating electric fields from vector magnetic field and Doppler measurements

    SciTech Connect

    Kazachenko, Maria D.; Fisher, George H.; Welsch, Brian T.

    2014-11-01

    Photospheric electric fields, estimated from sequences of vector magnetic field and Doppler measurements, can be used to estimate the flux of magnetic energy (the Poynting flux) into the corona and as time-dependent boundary conditions for dynamic models of the coronal magnetic field. We have modified and extended an existing method to estimate photospheric electric fields that combines a poloidal-toroidal decomposition (PTD) of the evolving magnetic field vector with Doppler and horizontal plasma velocities. Our current, more comprehensive method, which we dub the 'PTD-Doppler-FLCT Ideal' (PDFI) technique, can now incorporate Doppler velocities from non-normal viewing angles. It uses the FISHPACK software package to solve several two-dimensional Poisson equations, a faster and more robust approach than our previous implementations. Here, we describe systematic, quantitative tests of the accuracy and robustness of the PDFI technique using synthetic data from anelastic MHD (ANMHD) simulations, which have been used in similar tests in the past. We find that the PDFI method has less than 1% error in the total Poynting flux and a 10% error in the helicity flux rate at a normal viewing angle (θ = 0) and less than 25% and 10% errors, respectively, at large viewing angles (θ < 60°). We compare our results with other inversion methods at zero viewing angle and find that our method's estimates of the fluxes of magnetic energy and helicity are comparable to or more accurate than other methods. We also discuss the limitations of the PDFI method and its uncertainties.

  13. Lacunarity Measures of Potential Fields in Covered Lithology Identification

    NASA Astrophysics Data System (ADS)

    Gettings, M. E.

    2013-12-01

    Measure distributions, both multifractal and other kinds, are not unique, so spatial patterns with the same measure may have different appearances. Lacunarity analysis is a method of description of dispersion in spatial patterns across a range of scales, and is one way of descriminating clustering of similar values. Lacunarity of an image was calculated using a moving window across a range of scales as the ratio of the second moment divided by the square of the first moment for values within the window. This gives a curve of lacunarity versus resolution (scale); the curve is concave for highly clustered data, pseudolinear or convex for data with clusters at many scales such as multifractal simulations, and constant for uniformly spaced data. Breaks in slope of the curve indicate scales that are important in the structure of the spatial pattern. Gravity and magnetic field anomaly data are well known to be multifractal and thus calculated lacunarities of gridded datasets have been investigated to determine if the resulting curves are a useful measure of texture of the potential field data and helpful in identifying likely lithologies at depth beneath cover. Lacunarity is often calculated on binary data, but it can also be calculated using quantitative data. The quantitative data case lacunarity measure was computed for grids using a 25 by 25 km window moving over the grid, each window overlapping the previous one by 12.5 km. The data were the aeromagnetic and isostatic gravity anomaly grids for the state of Arizona at 0.5 km grid-interval, resulting in a lacunarity curves for gravity and aeromagnetic anomaly for each of approximately 2500 windows. The open-source software R was used for plotting a map of window center locations and lacunarity curves, and the map was loaded into Google Earth, together with maps of the gravity and magnetic field anomaly, porphyry copper deposit locations, and the geological map of Arizona. Windows were selected to compare lacunarity

  14. Ion temperature fluctuation measurements using a retarding field analyzer

    SciTech Connect

    Nedzelskiy, I. S.; Silva, C.; Duarte, P.; Fernandes, H.

    2011-04-15

    The retarding field analyzer (RFA) is a widely used diagnostic tool for the ion temperature measurement in the scrape-off-layer (SOL) of the thermonuclear plasma devices. However, the temporal resolution in the standard RFA application is restricted to the ms timescale. In this paper, a dc operation of the RFA is considered, which allows for the measurement of the plasma ion temperature fluctuations. The method is based on the relation for the RFA current-voltage (I-V) characteristic resulted from a common RFA model of shifted Maxwellian distribution of the analyzed ions, and the measurements of two points on the exponentially decaying region of the I-V characteristic with two differently dc biased RFA electrodes. The method has been tested and compared with conventional RFA measurements of the ion temperature in the tokamak ISTTOK SOL plasma. An ion temperature of T{sub i}= 17 eV is obtained near the limiter position. The agreement between the results of the two methods is within {approx}25%. The amplitude of the ion temperature fluctuations is found to be around 5 eV at this location. The method has been validated by taking into account the effect of fluctuations in the plasma potential and the noise contamination, proving the reliability of the results obtained. Finally, constrains to the method application are discussed that include a negligible electron emission from the RFA grids and the restriction to operate in the exponentially decaying region of the I-V characteristic.

  15. Ion temperature fluctuation measurements using a retarding field analyzer.

    PubMed

    Nedzelskiy, I S; Silva, C; Duarte, P; Fernandes, H

    2011-04-01

    The retarding field analyzer (RFA) is a widely used diagnostic tool for the ion temperature measurement in the scrape-off-layer (SOL) of the thermonuclear plasma devices. However, the temporal resolution in the standard RFA application is restricted to the ms timescale. In this paper, a dc operation of the RFA is considered, which allows for the measurement of the plasma ion temperature fluctuations. The method is based on the relation for the RFA current-voltage (I-V) characteristic resulted from a common RFA model of shifted Maxwellian distribution of the analyzed ions, and the measurements of two points on the exponentially decaying region of the I-V characteristic with two differently dc biased RFA electrodes. The method has been tested and compared with conventional RFA measurements of the ion temperature in the tokamak ISTTOK SOL plasma. An ion temperature of T(i) = 17 eV is obtained near the limiter position. The agreement between the results of the two methods is within ∼25%. The amplitude of the ion temperature fluctuations is found to be around 5 eV at this location. The method has been validated by taking into account the effect of fluctuations in the plasma potential and the noise contamination, proving the reliability of the results obtained. Finally, constrains to the method application are discussed that include a negligible electron emission from the RFA grids and the restriction to operate in the exponentially decaying region of the I-V characteristic.

  16. Evaluation of occupational cold environments: field measurements and subjective analysis.

    PubMed

    Oliveira, A Virgílio M; Gaspar, Adélio R; Raimundo, António M; Quintela, Divo A

    2014-01-01

    The present work is dedicated to the study of occupational cold environments in food distribution industrial units. Field measurements and a subjective assessment based on an individual questionnaire were considered. The survey was carried out in 5 Portuguese companies. The field measurements include 26 workplaces, while a sample of 160 responses was considered for the subjective assessment. In order to characterize the level of cold exposure, the Required Clothing Insulation Index (IREQ) was adopted. The IREQ index highlights that in the majority of the workplaces the clothing ensembles worn are inadequate, namely in the freezing chambers where the protection provided by clothing is always insufficient. The questionnaires results show that the food distribution sector is characterized by a female population (70.6%), by a young work force (60.7% are less than 35 yr old) and by a population with a medium-length professional career (80.1% in this occupation for less than 10 yr). The incidence of health effects which is higher among women, the distribution of protective clothing (50.0% of the workers indicate one garment) and the significant percentage of workers (>75%) that has more difficulties in performing the activity during the winter represent other important results of the present study.

  17. Warm Magnetic Field Measurements of LARP HQ Magnet

    SciTech Connect

    Caspi, S; Cheng, D; Deitderich, D; Felice, H; Ferracin, P; Hafalia, R; Joseph, J; Lizarazo, J; Martchevskii, M; Nash, C; Sabbi, G L; Vu, C; Schmalzle, J; Ambrosio, G; Bossert, R; Chlachidze, G; DiMarco, J; Kashikhin, V

    2011-03-28

    The US-LHC Accelerator Research Program is developing and testing a high-gradient quadrupole (HQ) magnet, aiming at demonstrating the feasibility of Nb{sub 3}Sn technologies for the LHC luminosity upgrade. The 1 m long HQ magnet has a 120 mm bore with a conductor-limited gradient of 219 T/m at 1.9 K and a peak field of 15 T. HQ includes accelerator features such as alignment and field quality. Here we present the magnetic measurement results obtained at LBNL with a constant current of 30 A. A 100 mm long circuit-board rotating coil developed by FNAL was used and the induced voltage and flux increment were acquired. The measured b{sub 6} ranges from 0.3 to 0.5 units in the magnet straight section at a reference radius of 21.55 mm. The data reduced from the numerical integration of the raw voltage agree with those from the fast digital integrators.

  18. Normalized velocity profiles of field-measured turbidity currents

    USGS Publications Warehouse

    Xu, Jingping

    2010-01-01

    Multiple turbidity currents were recorded in two submarine canyons with maximum speed as high as 280 cm/s. For each individual turbidity current measured at a fixed station, its depth-averaged velocity typically decreased over time while its thickness increased. Some turbidity currents gained in speed as they traveled downcanyon, suggesting a possible self-accelerating process. The measured velocity profiles, first in this high resolution, allowed normalizations with various schemes. Empirical functions, obtained from laboratory experiments whose spatial and time scales are two to three orders of magnitude smaller, were found to represent the field data fairly well. The best similarity collapse of the velocity profiles was achieved when the streamwise velocity and the elevation were normalized respectively by the depth-averaged velocity and the turbidity current thickness. This normalization scheme can be generalized to an empirical function Y = exp(–αXβ) for the jet region above the velocity maximum. Confirming theoretical arguments and laboratory results of other studies, the field turbidity currents are Froude-supercritical.

  19. Measuring marine oil spill extent by Markov Random Fields

    NASA Astrophysics Data System (ADS)

    Moctezuma, Miguel; Parmiggiani, Flavio; Lopez Lopez, Ludwin

    2014-10-01

    The Deepwater Horizon oil spill of the Gulf of Mexico in the spring of 2010 was the largest accidental marine oil spill in the history of the petroleum industry. An immediate request, after the accident, was to detect the oil slick and to measure its extent: SAR images were the obvious tool to be employed for the task. This paper presents a processing scheme based on Markov Random Fields (MRF) theory. MRF theory describes the global information by probability terms involving local neighborhood representations of the SAR backscatter data. The random degradation introduced by speckle noise is dealt with a pre-processing stage which applies a nonlinear diffusion filter. Spatial context attributes are structured by the Bayes equation derived from a Maximum-A-Posteriori (MAP) estimation. The probability terms define an objective function of a MRF model whose goal is to detect contours and fine structures. The markovian segmentation problem is solved with a numerical optimization method. The scheme was applied to an Envisat/ASAR image over the Gulf of Mexico of May 9, 2010, when the oil spill was already fully developed. The final result was obtained with 51 recursion cycles, where, at each step, the segmentation consists of a 3-class label field (open sea and two oil slick thicknesses). Both the MRF model and the parameters of the stochastic optimization procedure will be provided, together with the area measurement of the two kinds of oil slick.

  20. Field measurement of alkalinity and pH

    USGS Publications Warehouse

    Barnes, Ivan

    1964-01-01

    The behavior of electrometric pH equipment under field conditions departs from the behavior predicted from Nernst's law. The response is a linear function of pH, and hence measured pH values may be corrected to true pH if the instrument is calibrated with two reference solutions for each measurement. Alkalinity titrations may also be made in terms of true pH. Standard methods, such as colorimetric titrations, were rejected as unreliable or too cumbersome for rapid field use. The true pH of the end point of the alkalinity titration as a function of temperature, ionic strength, and total alkalinity has been calculated. Total alkalinity in potable waters is the most important factor influencing the end point pH, which varies from 5.38 (0 ? C, 5 ppm (parts per million) HC0a-) to 4.32 (300 ppm HC0a-,35 ? C), for the ranges of variables considered. With proper precautions, the pH may be determined to =i:0.02 pH and the alkalinity to =i:0.6 ppm HCO3- for many naturally occurring bodies of fresh water.

  1. Far-field measurements of short-wavelength surface plasmons

    SciTech Connect

    Blau, Yochai; Gjonaj, Bergin; David, Asaf; Dolev, Shimon; Shterman, Doron; Bartal, Guy

    2015-03-23

    We present direct far-field measurements of short-wavelength surface plasmon polaritons (SPP) by conventional optics means. Plasmonic wavelength as short as 231 nm was observed for 532 nm illumination on a Ag−Si{sub 3}N{sub 4} platform, demonstrating the capability to characterize SPPs well below the optical diffraction limit. This is done by scaling a sub-wavelength interferometric pattern to a far-field resolvable periodicity. These subwavelength patterns are obtained by coupling light into counter-propagating SPP waves to create a standing-wave pattern of half the SPP wavelength periodicity. Such patterns are mapped by a scattering slit, tilted at an angle so as to increase the periodicity of the intensity pattern along it to more than the free-space wavelength, making it resolvable by diffraction limited optics. The simplicity of the method as well as its large dynamic range of measurable wavelengths make it an optimal technique to characterize the properties of plasmonic devices and high-index dielectric waveguides, to improve their design accuracy and enhance their functionality.

  2. Doppler Global Velocimetry Measurements for Supersonic Flow Fields

    NASA Technical Reports Server (NTRS)

    Meyers, James F.

    2005-01-01

    The application of Doppler Global Velocimetry (DGV) to high-speed flows has its origins in the original development of the technology by Komine et al (1991). Komine used a small shop-air driven nozzle to generate a 200 m/s flow. This flow velocity was chosen since it produced a fairly large Doppler shift in the scattered light, resulting in a significant transmission loss as the light passed through the Iodine vapor. This proof-of-concept investigation showed that the technology was capable of measuring flow velocity within a measurement plane defined by a single-frequency laser light sheet. The effort also proved that velocity measurements could be made without resolving individual seed particles as required by other techniques such as Fringe- Type Laser Velocimetry and Particle Image Velocimetry. The promise of making planar velocity measurements with the possibility of using 0.1-micron condensation particles for seeding, Dibble et al (1989), resulted in the investigation of supersonic jet flow fields, Elliott et al (1993) and Smith and Northam (1995) - Mach 2.0 and 1.9 respectively. Meyers (1993) conducted a wind tunnel investigation above an inclined flat plate at Mach 2.5 and above a delta wing at Mach 2.8 and 4.6. Although these measurements were crude from an accuracy viewpoint, they did prove that the technology could be used to study supersonic flows using condensation as the scattering medium. Since then several research groups have studied the technology and developed solutions and methodologies to overcome most of the measurement accuracy limitations:

  3. Assessment of pressure field calculations from particle image velocimetry measurements

    NASA Astrophysics Data System (ADS)

    Charonko, John J.; King, Cameron V.; Smith, Barton L.; Vlachos, Pavlos P.

    2010-10-01

    This paper explores the challenges associated with the determination of in-field pressure from DPIV (digital particle image velocimetry)-measured planar velocity fields for time-dependent incompressible flows. Several methods that have been previously explored in the literature are compared, including direct integration of the pressure gradients and solution of different forms of the pressure Poisson equations. Their dependence on grid resolution, sampling rate, velocity measurement error levels and off-axis recording was quantified using artificial data of two ideal sample flow fields—a decaying vortex flow and pulsatile flow between two parallel plates, and real DPIV and pressure data from oscillating flow through a diffuser. The need for special attention to mitigate the velocity error propagation in the pressure estimation is also addressed using a physics-preserving approach based on proper orthogonal decomposition (POD). The results demonstrate that there is no unique or optimum method for estimating the pressure field and the resulting error will depend highly on the type of the flow. However, the virtual boundary, omni-directional pressure integration scheme first proposed by Liu and Katz (2006 Exp. Fluids 41 227-40) performed consistently well in both synthetic and experimental flows. Estimated errors can vary from less than 1% to over 100% with respect to the expected value, though in contrast to more traditional smoothing algorithms, the newly proposed POD-based filtering approach can reduce errors for a given set of conditions by an order of magnitude or more. This analysis offers valuable insight that allows optimizing the choice of methods and parameters based on the flow under consideration.

  4. Field Testing of a Wet FGD Additive for Enhanced Mercury Control - Task 5 Full-Scale Test Results

    SciTech Connect

    Gary Blythe; MariJon Owens

    2007-12-01

    This Topical Report summarizes progress on Cooperative Agreement DE-FC26-04NT42309, 'Field Testing of a Wet FGD Additive'. The objective of the project is to demonstrate the use of two flue gas desulfurization (FGD) additives, Evonik Degussa Corporation's TMT-15 and Nalco Company's Nalco 8034, to prevent the re-emission of elemental mercury (Hg{sup 0}) in flue gas exiting wet FGD systems on coal-fired boilers. Furthermore, the project intends to demonstrate whether the additive can be used to precipitate most of the mercury (Hg) removed in the wet FGD system as a fine salt that can be separated from the FGD liquor and bulk solid byproducts for separate disposal. The project is conducting pilot- and full-scale tests of the additives in wet FGD absorbers. The tests are intended to determine required additive dosages to prevent Hg{sup 0} re-emissions and to separate mercury from the normal FGD byproducts for three coal types: Texas lignite/Powder River Basin (PRB) coal blend, high-sulfur Eastern bituminous coal, and low-sulfur Eastern bituminous coal. The project team consists of URS Group, Inc., EPRI, Luminant Power (was TXU Generation Company LP), Southern Company, IPL (an AES company), Evonik Degussa Corporation and the Nalco Company. Luminant Power has provided the Texas lignite/PRB co-fired test site for pilot FGD tests and cost sharing. Southern Company has provided the low-sulfur Eastern bituminous coal host site for wet scrubbing tests, as well as the pilot- and full-scale jet bubbling reactor (JBR) FGD systems tested. IPL provided the high-sulfur Eastern bituminous coal full-scale FGD test site and cost sharing. Evonik Degussa Corporation is providing the TMT-15 additive, and the Nalco Company is providing the Nalco 8034 additive. Both companies are also supplying technical support to the test program as in-kind cost sharing. The project is being conducted in six tasks. Of the six project tasks, Task 1 involves project planning and Task 6 involves management

  5. Modeling and measurements of magnetic stochasticity and transport in the MST reversed field pinch

    NASA Astrophysics Data System (ADS)

    Hudson, Ben

    2002-11-01

    Results from experimental measurements and modeling of stochastic transport are beginning to agree. The modeling was done with a field line tracing code, which uses spatial profiles from a 3-D nonlinear MHD code, DEBS, and incorporates experimentally measured edge fluctuations. The modeling finds good agreement with Rechester - Rosenbluth diffusion just inside the reversal surface, where the islands highly overlap, and diverges from Rechester - Rosenbluth elsewhere. Electron heat transport is measured experimentally and agrees with the model to within a factor of three. Measurements of the drop in electron thermal transport in plasmas where fluctuations are suppressed by current profile manipulation are in agreement with the model. Recent measurements of the confinement of run-away electrons observed in the core suggest reformation of magnetic flux surfaces from a previously stochastic field. The modeling clearly shows this transition in profiles of radial magnetic field line diffusion. In addition we have started modeling of fast ion motion and new results on the effect of magnetic field stochasticity on the ion confinement will be reported. Work supported by U.S. D.O.E.

  6. Redox potential - field measurements - meassured vs. expected values

    NASA Astrophysics Data System (ADS)

    Stavělová, Monika; Kovář, Martin

    2016-04-01

    Oxidation and reduction (redox) potential is an important and theoretically very well defined parameter and can be calculated accurately. Its value is determinative for management of many electrochemical processes, chemical redox technologies as well as biotechnologies. To measure the redox value that would correspond with the accuracy level of theoretical calculations in field or operational conditions is however nearly impossible. Redox is in practice measured using combined argentochloride electrode with subsequent value conversion to standard hydrogen electrode (EH). Argentochloride electrode does not allow for precise calibration. Prior to the measurement the accuracy of measurement of particular electrode can only be verified in comparative/control solution with value corresponding with oxic conditions (25°C: +220 mV argentochloride electrode, i.e.. +427 mV after conversion to EH). A commercial product of stabile comparative solution for anoxic conditions is not available and therefore not used in every day practice - accuracy of negative redox is not verified. In this presentation results of two tests will be presented: a) monitoring during dynamic groundwater sampling from eight monitoring wells at a site contaminated by chlorinated ethenes (i.e. post-oxic to anoxic conditions) and b) laboratory test of groundwater contaminated by arsenic from two sites during reaction with highly oxidized compounds of iron (ferrates) - i.e. strongly oxic conditions. In both tests a simultaneous measurement by four argentochloride electrodes was implemented - all four electrodes were prior to the test maintained expertly. The redox values of testing electrodes in a comparative solution varied by max. 6 mV. The redox values measured by four electrodes in both anoxic and oxic variant varied by tens to a hundred mV, while with growing time of test the variance of measured redox values increased in both oxic and anoxic variant. Therefore the interpretation of measured redox

  7. Semi-empirical equation of limiting current for cobalt electrodeposition in the presence of magnetic field and additive electrolyte

    NASA Astrophysics Data System (ADS)

    Sudibyo, Aziz, N.

    2016-02-01

    One of the available methods to solve a roughening in cobalt electrodeposition is magneto electrodeposition (MED) in the presence of additive electrolyte. Semi-empirical equation of limiting current under a magnetic field for cobalt MED in the presence of boric acid as an additive electrolyte was successfully developed. This semi empirical equation shows the effects of the electrode area (A), the concentration of the electro active species (C), the diffusion coefficient of the electro active species (D), the kinematic viscosity of the electrolyte (v), magnetic strength (B) and the number of electrons involved in the redox process (n). The presence of boric acid led to decrease in the limiting current, but the acid was found useful as a buffer to avoid the local pH rise caused by parallel hydrogen evolution reaction (HER).

  8. Exploring the origin of magnetic fields in massive stars. II. New magnetic field measurements in cluster and field stars

    NASA Astrophysics Data System (ADS)

    Hubrig, S.; Schöller, M.; Ilyin, I.; Kharchenko, N. V.; Oskinova, L. M.; Langer, N.; González, J. F.; Kholtygin, A. F.; Briquet, M.; Magori Collaboration

    2013-03-01

    Context. Theories on the origin of magnetic fields in massive stars remain poorly developed, because the properties of their magnetic field as function of stellar parameters could not yet be investigated. Additional observations are of utmost importance to constrain the conditions that are conducive to magnetic fields and to determine first trends about their occurrence rate and field strength distribution. Aims: To investigate whether magnetic fields in massive stars are ubiquitous or appear only in stars with a specific spectral classification, certain ages, or in a special environment, we acquired 67 new spectropolarimetric observations for 30 massive stars. Among the observed sample, roughly one third of the stars are probable members of clusters at different ages, whereas the remaining stars are field stars not known to belong to any cluster or association. Methods: Spectropolarimetric observations were obtained during four different nights using the low-resolution spectropolarimetric mode of FOcal Reducer low dispersion Spectrograph (FORS 2) mounted on the 8-m Antu telescope of the VLT. Furthermore, we present a number of follow-up observations carried out with the high-resolution spectropolarimeters SOFIN mounted at the Nordic Optical Telescope (NOT) and HARPS mounted at the ESO 3.6 m between 2008 and 2011. To assess the membership in open clusters and associations, we used astrometric catalogues with the highest quality kinematic and photometric data currently available. Results: The presence of a magnetic field is confirmed in nine stars previously observed with FORS 1/2: HD 36879, HD 47839, CPD-28 2561, CPD-47 2963, HD 93843, HD 148937, HD 149757, HD 328856, and HD 164794. New magnetic field detections at a significance level of at least 3σ were achieved in five stars: HD 92206c, HD 93521, HD 93632, CPD-46 8221, and HD 157857. Among the stars with a detected magnetic field, five stars belong to open clusters with high membership probability. According to

  9. Laboratory and field evaluation of a combined fluid-loss-control additive and gel breaker for fracturing fluids

    SciTech Connect

    Cantu, L.A.; Boyd, P.A. )

    1990-08-01

    More than 200% increase in fracture conductivity and permeability was obtained when a new degradable fluid-loss-control additive was used in place of silica flour (SF) in 40-lbm crosslinked hydroxypropyl-guar (HPG) fracturing-fluid systems. The new additive, and organic acid particulate (OAP), slowly degraded into water-soluble monomeric units at temperatures {ge}150{degrees}F after fracture stimulation experiments. The high-acid-content degradation product then acted as an excellent HPG gel breaker and effectively cleaned the proppant packs. As a fluid-loss-control additive, the measured wall-building coefficients were as good as, or better than, those of SF in crosslinked-gel, linear-gel, and N{sub 2}-foam systems. This paper summarizes a 2-year study of the evaluation and application of this new product in fracturing-fluid systems.

  10. Measuring Children's Proportional Reasoning, The "Tendency" for an Additive Strategy and The Effect of Models

    ERIC Educational Resources Information Center

    Misailadou, Christina; Williams, Julian

    2003-01-01

    We report a study of 10-14 year old children's use of additive strategies while solving ratio and proportion tasks. Rasch methodology was used to develop a diagnostic instrument that reveals children's misconceptions. Two versions of this instrument, one with "models" thought to facilitate proportional reasoning and one without were…

  11. Strong field radio-frequency measurements using Rydberg states in a vapor cell

    NASA Astrophysics Data System (ADS)

    Miller, Stephanie; Anderson, David; Raithel, Georg

    2016-05-01

    There has been a growing interest in using electromagnetically induced transparency with Rydberg atoms in a room-temperature vapor cell as an all-optical readout method for measuring microwave electric fields. We present results from RF-modulating the 60S1 / 2 and 58D5 / 2 Rydberg states of rubidium with 50 MHz and 100 MHz fields, respectively. Weak RF fields AC Stark-shifts the Rydberg states. As the field strength is increased, sidebands appear at even multiples of the driving frequency. When strong fields are applied, the nearby hydrogenic manifold begins to intersect with the shifted levels. Similar investigations have been performed in cesium. Due to the significant amount of state mixing and level structure, Floquet theory is required to describe the level shifts and mixing. By comparing the calculation with the experimental data, we obtain an absolute determination of the RF electric field reaching a maximum field of 296 V/m to within +/- 0 . 35 % . Additionally, we estimate the shielding of DC fields within the vapor cell.

  12. Method of measuring field funneling and range straggling in semiconductor charge-collecting junctions

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A. (Inventor); Malone, Carl J. (Inventor)

    1987-01-01

    Electric-field funneling length is measured while irradiating a semiconductor charge-collecting junction with electron-hole-pair generating charged particles at a first junction bias voltage. The bias voltage is then reduced to a second level in order to reduce the depth of the depletion region such that the total charge can no longer be collected by drift and measured in the energy band previously displayed in the multichannel analyzer. This is representative of the maximum electric field funnelling length which may be calculated by measuring the difference at the second bias voltage level of the depletion width and the ion penetration range. The bias voltage is further lowered to a third level at which the particles are collected over a spread of energy levels while at least some of the particles are still collected at the selected energy level. From this the different depths of penetration of the particles are determined while additional effects due to diffusion are minimized.

  13. Method of measuring field funneling and range straggling in semiconductor charge-collecting junctions

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A. (Inventor)

    1985-01-01

    Electric-field funneling length is measured while irradiating a semiconductor charge-collecting junction with electron-hole-pair generating charged particles at a first junction bias voltage. The bias voltage is then reduced to a second level in order to reduce the depth of the depletion region such that the total charge can no longer be collected by drift and measured in the energy band previously displayed in the multichannel analyzer. This is representative of the maximum electric field funneling length which may be calculated by measuring the difference at the second bias voltage level of the depletion width and the ion penetration range. The bias voltage is further lowered to a third level at which the particles are collected over a spread of energy levels while at least some of the particles are still collected at the selected energy level. From this the different depths of penetration of the particles are determined while additional effects due to diffusion are minimized.

  14. Real exposure: field measurement of chemical plumes in headwater streams.

    PubMed

    Edwards, David D; Moore, Paul A

    2014-10-01

    In fluvial systems, organismic exposure to nonpoint source pollutants will fluctuate in frequency (exposure events), intensity (concentration), and duration. The reliance on lethal concentrations and static exposure in many laboratory studies does not adequately represent nor address exposure to in situ chemical plumes of fluvial habitats. To adequately address field exposure in a laboratory setting, one needs an understanding of the physics of chemical transmission within moving fluids. Because of the chaotic nature of turbulence, chemical plumes introduced to fluvial systems have a spatial and temporal microstructure with fluxes in chemical concentration. Consequently, time-averaged static exposure models are not ecologically relevant for the major reason of in situ distribution. The purpose of this study was to quantify in situ chemical distribution and dispersion within two physically different streams. Dopamine was introduced as a chemical tracer mimicking groundwater runoff. Chemical fluxes and stream hydrodynamics were simultaneously measured using a microelectrode and an acoustic Doppler velocimeter, respectively, at three heights of three downstream locations at each research site. Fine-scale measurements of the dopamine plume microstructure showed that organisms could be exposed to chemical fluctuations where concentrations are significantly greater than the overall time-averaged concentration. These measurements demonstrate that rather than relying on static exposure, standards for pollution must consider the concept of exposure being interdependently linked to flow of the fluid medium. The relationship between fluid dynamics, pollution exposure, and organism physiology are complex and must be evaluated in ways to mimic natural systems.

  15. Real exposure: Field measurement of chemical plumes in headwater streams

    NASA Astrophysics Data System (ADS)

    Edwards, David D.

    In fluvial systems, organismic exposure to nonpoint source pollutants will fluctuate in frequency (exposure events), intensity (concentration), and duration. The reliance on lethal concentrations and static exposure in many laboratory studies does not adequately represent nor address exposure to in situ chemical plumes of fluvial habitats. In order to adequately address field exposure in a lab setting, one needs an understanding of the physics of chemical transmission within moving fluids. Because of the chaotic nature of turbulence, chemical plumes introduced to fluvial systems have a spatial and temporal microstructure with fluxes in chemical concentration. Consequently, time-averaged static exposure models are not ecologically relevant for the major reason of in situ distribution. The purpose of this study was to quantify in situ chemical distribution and dispersion within two physically different streams. Dopamine was introduced as a chemical tracer mimicking groundwater runoff. Chemical fluxes and stream hydrodynamics were simultaneously measured using a microelectrode and an acoustic doppler velocimeter (ADV), respectively, at three heights of three downstream locations at each research site. Fine-scale measurements of the dopamine plume microstructure showed organisms could be exposed to chemical fluctuations where concentrations are significantly greater than the overall time-averaged concentration. These measurements demonstrate that rather than relying on static exposure, standards for pollution need to consider the concept of exposure being interdependently linked to flow of the fluid medium. The relationship between fluid dynamics, pollution exposure and organism physiology are complex and need to be evaluated in ways to mimic natural systems.

  16. Field temperature measurements at Erta'Ale Lava Lake, Ethiopia

    NASA Astrophysics Data System (ADS)

    Burgi, Pierre-Yves; Caillet, Marc; Haefeli, Steven

    2002-06-01

    The shield volcano Erta'Ale, situated in the Danakil Depression, Ethiopia, is known for its active lava lake. In February 2001, our team visited this lake, located inside an 80-m-deep pit, to perform field temperature measurements. The distribution and variation of temperature inside the lake were obtained on the basis of infrared radiation measurements performed from the rim of the pit and from the lake shores. The crust temperature was also determined from the lake shores with a thermocouple to calibrate the pyrometer. We estimated an emissivity of the basalt of 0.74 from this experiment. Through the application of the Stefan-Boltzmann law, we then obtained an estimate of the total radiative heat flux, constrained by pyrometer measurements of the pit, and visual observations of the lake activity. Taking into account the atmospheric convective heat flux, the convected magma mass flux needed to balance the energy budget was subsequently derived and found to represent between 510 and 580 kg s-1. The surface circulation of this mass flux was also analyzed through motion processing techniques applied to video images of the lake. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00445-002-0224-3.

  17. Measurements of Electric Field Fluctuations Using a Capacitive Probe on the MST Reversed Field Pinch

    NASA Astrophysics Data System (ADS)

    Tan, Mingsheng; Almagri, A. F.; Sarff, J. S.; McCollam, K. J.; Triana, J. C.; Li, H.; Ding, W. X.; Liu, W.

    2015-11-01

    Experimental measurements and extended MHD computation reveal that both flow and current density fluctuations are important for the magnetic relaxation of RFP plasmas via tearing fluctuations. Motivated by these results, we have developed a multi-electrode capacitive probe for radial profile measurements of the electrostatic potential deep in the plasma. The capacitive probe measures the ac plasma potential via electrodes insulated from the plasma using an annular boron nitride dielectric (also the particle shield), provided the secondary emission is sufficiently large (Te>20 eV). The probe has ten sets of four capacitors with 1.5 cm radial separation. At each radius, four capacitors are arranged on a 1.3 cm square grid. This probe has been inserted up to 15 cm from the wall in 200 kA deuterium plasmas. The fluctuation amplitudes increase during the sawtooth crash and the power spectrum broadens (similar to the behavior of magnetic field fluctuations). The frequency bandwidth allows measurements of the radial coherence and phase of the fluctuations associated with rotating tearing modes up to the Alfvénic range. A next-step goal is measurement of the total dynamo emf, ~ < E ~ . B ~ > /B0 , to complement ongoing measurements of the Hall dynamo emf, < J ~ × B ~ > / ne , using a deep-insertion magnetic probe. M. Tan is supported by ITER-China Program. Work is supported by US DOE.

  18. Measurement of two-dimensional Doppler wind fields using a field widened Michelson interferometer.

    PubMed

    Langille, Jeffery A; Ward, William E; Scott, Alan; Arsenault, Dennis L

    2013-03-10

    An implementation of the field widened Michelson concept has been applied to obtain high resolution two-dimensional (2D) images of low velocity (<50 m/s) Doppler wind fields in the lab. Procedures and techniques have been developed that allow Doppler wind and irradiance measurements to be determined on a bin by bin basis with an accuracy of less than 2.5 m/s from CCD images over the observed field of view. The interferometer scanning mirror position is controlled to subangstrom precision with subnanometer repeatability using the multi-application low-voltage piezoelectric instrument control electronics developed by COM DEV Ltd.; it is the first implementation of this system as a phase stepping Michelson. In this paper the calibration and characterization of the Doppler imaging system is described and the planned implementation of this new technique for imaging 2D wind and irradiance fields using the earth's airglow is introduced. Observations of Doppler winds produced by a rotating wheel are reported and shown to be of sufficient precision for buoyancy wave observations in airglow in the mesopause region of the terrestrial atmosphere.

  19. Voice measures of workload in the advanced flight deck: Additional studies

    NASA Technical Reports Server (NTRS)

    Schneider, Sid J.; Alpert, Murray

    1989-01-01

    These studies investigated acoustical analysis of the voice as a measure of workload in individual operators. In the first study, voice samples were recorded from a single operator during high, medium, and low workload conditions. Mean amplitude, frequency, syllable duration, and emphasis all tended to increase as workload increased. In the second study, NASA test pilots performed a laboratory task, and used a flight simulator under differing work conditions. For two of the pilots, high workload in the simulator brought about greater amplitude, peak duration, and stress. In both the laboratory and simulator tasks, high workload tended to be associated with more statistically significant drop-offs in the acoustical measures than were lower workload levels. There was a great deal of intra-subject variability in the acoustical measures. The results suggested that in individual operators, increased workload might be revealed by high initial amplitude and frequency, followed by rapid drop-offs over time.

  20. Additional atmospheric opacity measurements at lambda = 1.1 mm from Mauna Kea Observatory, Hawaii

    NASA Technical Reports Server (NTRS)

    Parrish, A.; De Zafra, R. L.; Barrett, J. W.; Solomon, P.; Connor, B.

    1987-01-01

    Atmospheric opacity values in the zenith direction are given for a wavelength of 1.1 mm (278 GHz) at the summit of Mauna Kea in the Hawaiian Islands. A total of 75 days is covered during the period 1983-1986. Observations were made on a quasi-continuous basis, with opacity measured every 20 minutes around the clock for significant periods of time. A conversion from opacity at lambda = 1.1 mm to the equivalent precipitable water vapor column is given from the measurements of Zammit and Ade (1981), from which opacities at other wavelengths may be derived.

  1. Alignment and measurement of the magnetic field for the BESIII muon counter

    NASA Astrophysics Data System (ADS)

    Gao, Qing; Zhang, Jing-Zhi; Li, Chun-Hua; Yin, Jun-Hao

    2016-11-01

    Based on cosmic ray events without a magnetic field taken with the BESIII detector during the summer shutdown of BEPCII in 2012 and di-muon events from a data sample taken at center-of-mass energy of 3.686 GeV in 2009, we compare the coordinates of hits registered in the BESIII muon counter with the expected interaction point extrapolated from reconstructed tracks from the inner tracking system in the absence of a magnetic field. By minimizing the difference, we align the muon counter with the inner tracking system. Moreover, the strength of the magnetic field in the muon counter is measured for the first time with di-muon events from data taken at a center-of-mass energy of 3.686 GeV. After the alignment and the magnetic field strength measurement, the offsets in the reconstructed hit positions for muon tracks are reduced, which improves the muon identification. The alignment and magnetic field strength measurement have been adopted in the latest version of the BESIII offline software system. This addition to the software reduces the systematic uncertainty for the physics analysis in cases where the muon counter information is used. Supported by National Key Basic Research Program of China (2015CB856701), National Natural Science Foundation of China (NSFC) (11475187, 11575198, 11521505), 100 Talents Program of CAS (U-25)

  2. Fully automated measurement of field-dependent AMS using MFK1-FA Kappabridge equipped with 3D rotator

    NASA Astrophysics Data System (ADS)

    Chadima, Martin; Studynka, Jan

    2013-04-01

    Low-field magnetic susceptibility of paramagnetic and diamagnetic minerals is field-independent by definition being also field-independent in pure magnetite. On the other hand, in pyrrhotite, hematite and high-Ti titanomagnetite it may be clearly field-dependent. Consequently, the field-dependent AMS enables the magnetic fabric of the latter group of minerals to be separated from the whole-rock AMS. The methods for the determination of the field-dependent AMS consist of separate measurements of each specimen in several fields within the Rayleigh Law range and subsequent processing in which the field-independent and field-dependent AMS components are calculated. The disadvantage of this technique is that each specimen must be measured several times, which is relatively laborious and time consuming. Recently, a new 3D rotator was developed for the MFK1-FA Kappabridge, which rotates the specimen simultaneously about two axes with different velocities. The measurement is fully automated in such a way that, once the specimen is inserted into the rotator, it requires no additional manipulation to measure the full AMS tensor. Consequently, the 3D rotator enables to measure the AMS tensors in the pre-set field intensities without any operator interference. Whole procedure is controlled by newly developed Safyr5 software; once the measurements are finished, the acquired data are immediately processed and can be visualized in a standard way.

  3. Voyager measurement of the rotation period of Saturn's magnetic field

    NASA Technical Reports Server (NTRS)

    Desch, M. D.; Kaiser, M. L.

    1981-01-01

    Saturn's radio rotation period was determined using measurements made by the planetary radio astronomy experiment onboard the Voyager spacecraft. The sidereal period deduced, 10 hr 39 min 24 sec ? 7 sec, is within the 10 hr to 11 hr range of optical periods derived from a century of atmospheric spot and Doppler spectroscopy observations. The radio rotation period is presumably that of the planet's magnetic field. A provisional Saturn longitude convention is proposed and equations are provided to compute a longitude ephemeris and to transform between the proposed system and the (10 hr 14 min) system used for the Pioneer 11/Saturn encounter. The degree of longitude smearing which could result over the long term from the merging of data sets organized in this system is evaluated. No evidence of control of the radio emission by any of Saturn's satellites was found.

  4. Electric field and plasma density measurements in the auroral electrojet

    NASA Astrophysics Data System (ADS)

    Pfaff, R. F.; Kelley, M. C.; Fejer, B. G.; Kudeki, E.; Carlson, C. W.; Pedersen, A.; Hausler, B.

    1984-01-01

    Extensive experimental and theoretical studies of auroral and equatorial electrojet irregularities have been conducted for the last two decades. The present investigation is concerned with electric field and plasma density fluctuation measurements made on board of the Porcupine II sounding rocket and on a free-flyer ejected from the main spacecraft. The Porcupine II sounding rocket payload was launched at 1922:00 UT from Kiruna, Sweden, on March 20, 1977. The considered results show electrostatic turbulence in the unstable auroral E region confined to a layer between 96 and 121 km. The similarities between the observations of two simultaneous payloads spaced a few kilometers apart indicate that on a large scale, the electrojet turbulence displays uniform characteristics.

  5. Field measurements of the spectral response of natural waters

    NASA Technical Reports Server (NTRS)

    Bartolucci, L. A.; Robinson, B. F.; Silva, L. F.

    1977-01-01

    The spectral response (air-water interface reflectance and water-volume scattering) of turbid river water (99 mg/liter suspended solids) and relatively clear lake water (10 mg/liter suspended solids) was measured in situ with a field spectroradiometer. The influence of the river bottom on the spectral response of the water also was determined by using a modified Secchi disc approach. The results indicated that turbid river water had a higher spectral response than clear lake water (about 6 percent) in the red (0.6-0.7 micron) and near-infrared (0.7-0.9 micron) portions of the spectrum. Also, the reflectance characteristics of the river bottom did not influence the spectral response of the turbid river water when the water was deeper than 30 cm

  6. Far-field measurements of vortex beams interacting with nanoholes

    PubMed Central

    Zambrana-Puyalto, Xavier; Vidal, Xavier; Fernandez-Corbaton, Ivan; Molina-Terriza, Gabriel

    2016-01-01

    We measure the far-field intensity of vortex beams going through nanoholes. The process is analyzed in terms of helicity and total angular momentum. It is seen that the total angular momentum is preserved in the process, and helicity is not. We compute the ratio between the two transmitted helicity components, γm,p. We observe that this ratio is highly dependent on the helicity (p) and the angular momentum (m) of the incident vortex beam in consideration. Due to the mirror symmetry of the nanoholes, we are able to relate the transmission properties of vortex beams with a certain helicity and angular momentum, with the ones with opposite helicity and angular momentum. Interestingly, vortex beams enhance the γm,p ratio as compared to those obtained by Gaussian beams. PMID:26911547

  7. Cloud Physics Lidar Measurements During the SAFARI-2000 Field Campaign

    NASA Technical Reports Server (NTRS)

    McGill, Matthew; Hlavka, Dennis; Hart, William; Spinhirne, James; Scott, Stan; Starr, David OC. (Technical Monitor)

    2001-01-01

    A new remote sensing instrument, the Cloud Physics Lidar (CPL) has been built for use on the ER-2 aircraft. The first deployment for CPL was the SAFARI-2000 field campaign during August-September 2000. The CPL is a three-wavelength lidar designed for studies of cirrus, subvisual cirrus, and boundary layer aerosols. The CPL utilizes a high repetition rate, low pulse energy laser with photon counting detectors. A brief description of the CPL instrument will be given, followed by examples of CPL data products. In particular, examples of aerosol backscatter, including boundary layer smoke and cirrus clouds will be shown. Resulting optical depth estimates derived from the aerosol measurements will be shown. Comparisons of the CPL optical depth and optical depth derived from microPulse Lidar and the AATS-14 sunphotomer will be shown.

  8. An instrument for measuring thermal inertia in the field

    NASA Technical Reports Server (NTRS)

    Marsh, S. E.; Schieldge, J. P.; Kahle, A. B.

    1982-01-01

    Features and test results of a thermal inertial meter (TIM) for cataloging the thermal inertial of surface material in situ as a basis for satellite remote sensing of geologic materials are described. The instrument is employed to determine the temperature rise of the materials in the field, with the assumptions that the sample and a standard are homogeneous in composition, the heat flux density is constant at the surface of each material, and the specimens are thick enough to be treated as semi-infinite bodies. A formula for calculating thermal inertia is presented, and the components of the TIM are detailed. A box with three compartments, two holding standards, is placed on the sample surface with the third compartment open to the specimen. Dolomite and quartz are used as references when all samples are measured after heating. Tests with rocks and sand in Nevada and California revealed that chert has a higher thermal inertia than barite.

  9. 40 CFR 52.1163 - Additional control measures for East Boston.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...”) shall each submit to the Regional Administrator a study or studies of various alternative strategies to... consistent with the national primary ambient air quality standards. These studies may be combined into one or more joint studies. These studies shall contain recommendations for control measures to be...

  10. 40 CFR 52.1163 - Additional control measures for East Boston.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...”) shall each submit to the Regional Administrator a study or studies of various alternative strategies to... consistent with the national primary ambient air quality standards. These studies may be combined into one or more joint studies. These studies shall contain recommendations for control measures to be...

  11. Measurement of Insertion Loss of an Acoustic Treatment in the Presence of Additional Uncorrelated Sound Sources

    NASA Technical Reports Server (NTRS)

    Klos, Jacob; Palumbo, Daniel L.

    2003-01-01

    A method to intended for measurement of the insertion loss of an acoustic treatment applied to an aircraft fuselage in-situ is documented in this paper. Using this method, the performance of a treatment applied to a limited portion of an aircraft fuselage can be assessed even though the untreated fuselage also radiates into the cabin, corrupting the intensity measurement. This corrupting noise in the intensity measurement incoherent with the panel vibration of interest is removed by correlating the intensity to reference transducers such as accelerometers. Insertion loss of the acoustic treatments is estimated from the ratio of correlated intensity measurements with and without a treatment applied. In the case of turbulent boundary layer excitation of the fuselage, this technique can be used to assess the performance of noise control methods without requiring treatment of the entire fuselage. Several experimental studies and numerical simulations have been conducted, and results from three case studies are documented in this paper. Conclusions are drawn about the use of this method to study aircraft sidewall treatments.

  12. An Additional Measure of Overall Effect Size for Logistic Regression Models

    ERIC Educational Resources Information Center

    Allen, Jeff; Le, Huy

    2008-01-01

    Users of logistic regression models often need to describe the overall predictive strength, or effect size, of the model's predictors. Analogs of R[superscript 2] have been developed, but none of these measures are interpretable on the same scale as effects of individual predictors. Furthermore, R[superscript 2] analogs are not invariant to the…

  13. 42 CFR 414.1230 - Additional measures for groups of physicians.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... diabetes. The rate of potentially preventable hospital admissions for diabetes is a composite measure of uncontrolled diabetes, short term diabetes complications, long term diabetes complications and lower extremity amputation for diabetes. (b) A composite of rates of potentially preventable hospital admissions...

  14. 42 CFR 414.1230 - Additional measures for groups of physicians.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... diabetes. The rate of potentially preventable hospital admissions for diabetes is a composite measure of uncontrolled diabetes, short term diabetes complications, long term diabetes complications and lower extremity amputation for diabetes. (b) A composite of rates of potentially preventable hospital admissions...

  15. Turbulence measurements over immobile gravel with additions of sand from supply limited to capacity transport conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measurement of the turbulence that drives sand transport over and through immobile gravels is relevant to efforts to model sediment movement downstream of dams, where fine sediments are eroded from coarse substrates and are not replaced due to the presence of the upstream dam. The relative elevatio...

  16. Field measurements in the wake of a model wind turbine

    NASA Astrophysics Data System (ADS)

    Pol, Suhas; Taylor, Amelia; Bilbao, Argenis; Doostalab, Ali; Novoa, Santiago; Westergaard, Carsten; Hussain, Fazle; Sheng, Jian; Ren, Beibei; Giesselmann, Michael; Glauser, Mark; Castillo, Luciano

    2014-06-01

    As a first step to study the dynamics of a wind farm' we experimentally explored the flow field behind a single wind turbine of diameter 1.17 m at a hub height of 6.25 m. A 10 m tower upstream of the wind farm characterizes the atmospheric conditions and its influence on the wake evolution. A vertical rake of sonic anemometers is clustered around the hub height on a second tower' 6D downstream of the turbine. We present preliminary observations from a 1- hour block of data recorded in near-neutral atmospheric conditions. The ratio of the standard deviation of power to the inflow velocity is greater than three' revealing adverse effects of inflow turbulence on the power and load fluctuations. Furthermore' the wake defect and Reynolds stress and its gradient are pronounced at 6D. The flux of energy due to Reynolds stresses is similar to that reported in wind tunnel studies. The swirl and mixing produces a constant temperature wake which results in a density jump across the wake interface. Further field measurements will explore the dynamics of a model wind farm' including the effects of atmospheric variability.

  17. Insights into lateral marsh retreat mechanism through localized field measurements

    NASA Astrophysics Data System (ADS)

    Bendoni, M.; Mel, R.; Solari, L.; Lanzoni, S.; Francalanci, S.; Oumeraci, H.

    2016-02-01

    Deterioration of salt marshes may be due to several factors related to increased anthropic pressure, sea level rise, and erosive processes. While salt marshes can reach equilibrium in the vertical direction, adapting to sea level rise, they are inherently unstable in the horizontal direction. Marsh boundaries are characterized by scarps with bare sediment below the vegetated surface layer that can be easily removed by wave-induced erosion. In this work, we explore the different mechanisms involved in the erosion of marsh borders through the interpretation of field data. The analysis is based on a systematic field monitoring of a salt marsh in the Venice Lagoon subject to lateral erosion. Measurements included horizontal retreat of the scarp at various locations and wave height in front of the marsh during three storm surges. Continuous erosion and mass failures alternated during the observed period, leading to an average retreat up to 80 cm/yr. The data, collected roughly every month for 1.5 year, indicate that the linear relation that links the observed erosion rate to the impinging wave power exhibits a larger slope than that already estimated in literature on the basis of long-term surveys. Moreover, an increase in the gradient of erodibility is detected along the marsh scarp, due to the combined action of soil strengthening by vegetation on the marsh surface and the impact of wave breaking at the bank toe, which promote cantilever failures and increase the lateral erosion rate.

  18. Measuring Fast Ion Losses in a Reversed Field Pinch Plasma

    NASA Astrophysics Data System (ADS)

    Bonofiglo, P. J.; Anderson, J. K.; Almagri, A. F.; Kim, J.; Clark, J.; Capecchi, W.; Sears, S. H.

    2015-11-01

    The reversed field pinch (RFP) provides a unique environment to study fast ion confinement and transport. The RFP's weak toroidal field, strong magnetic shear, and ability to enter a 3D state provide a wide range of dynamics to study fast ions. Core-localized, 25 keV fast ions are sourced into MST by a tangentially injected hydrogen/deuterium neutral beam. Neutral particle analysis and measured fusion neutron flux indicate enhanced fast ion transport in the plasma core. Past experiments point to a dynamic loss of fast ions associated with the RFP's transition to a 3D state and with beam-driven, bursting magnetic modes. Consequently, fast ion transport and losses in the RFP have garnered recent attention. Valuable information on fast-ion loss, such as energy and pitch distributions, are sought to provide a better understanding of the transport mechanisms at hand. We have constructed and implemented two fast ion loss detectors (FILDs) for use on MST. The FILDs have two, independent, design concepts: collecting particles as a function of v⊥ or with pitch greater than 0.8. In this work, we present our preliminary findings and results from our FILDs on MST. This research is supported by US DOE.

  19. Chemical, Biological, and Explosive Sensors for Field Measurements

    SciTech Connect

    Kevin Kyle, Manuel Manard, Stephan Weeks

    2009-01-31

    Special Technologies Laboratory (STL) is developing handheld chemical, biological, and explosive (CBE) detection systems and sensor motes for wireless networked field operations. The CBE sensors are capable of detecting and identifying multiple targeted toxic industrial chemicals (TICs) and high-explosive vapor components. The CBE devices are based on differential mobility spectrometry (DMS) coupled with fast gas chromatography (GC) or mass spectrometry. The systems all include the concepts of: 1. Direct air/particulate “smart” sampling 2. Selective, continuous real-time (~1 sec) alert monitoring using DMS 3. Highly selective, rapid dual technology separation/verification analysis The biosensor technology is based on Raman aerosol particle flow cytometry for target detection and identification. Monitoring and identifying trace level chemical vapors directly from ambient air will allow First Responders to quickly adapt situational response strategies and personal protective equipment needs to the specific response scenario being encountered. First Responders require great confidence in the measurements and ability of a given system to detect CBE below threshold levels without interferences. The concept of determining the background matrix in near real-time to allow subsequent automated field-programmable method selection and cueing of high-value assets in a wide range of environs will be presented. This provides CBE information for decisions prior to First Responders entering the response site or sending a portable mobile unit for a remote site survey of the hazards. The focus is on real-time information needed by those responsible for emergency response and national security.

  20. Bio-micrometeorological field measurements over heterogeneous surfaces

    NASA Astrophysics Data System (ADS)

    Kochendorfer, John

    Scientists have left the flat and homogeneous sites where the foundation of micrometeorology was established in order to better describe the complexity and magnitude of ecosystem contributions to the hydrologic and carbon cycles. Despite their acknowledged shortcomings, the techniques currently employed for this work still rely upon site selection criteria which are rarely met. The focus of this dissertation is the development of novel and theoretically sound methods of quantifying the effects of heterogeneity on surface-atmosphere exchange. The primary objectives of this dissertation are: (1) estimate evapotranspiration, the net ecosystem exchange of carbon dioxide, and canopy conductance from a riparian forest, (2) analyze the environmental controls of the above riparian processes, (3) estimate the errors introduced by the limited horizontal extent of the riparian forest, (4) measure horizontal advection and vertical scalar fluxes near the edge of an agricultural canopy, (5) measure energy balance closure near the edge of an agricultural canopy and evaluate the effects of the often-excluded advection terms on the energy budget, and (6) compare measured turbulent statistics and scalar transport to a higher-order closure model that has not been validated due to a lack of available field studies. Chapter 2 focuses on evapotranspiration and CO2 fluxes measured above a riparian Populus fremontii forest. Chapter 3 describes the results of a micrometeorological edge experiment performed in an agricultural crop, and in Chapter 4 the results presented in Chapter 3 are compared to a higher-order closure model. The results of the riparian work demonstrate the importance of local hydrology on the ecosystem fluxes of carbon dioxide and water vapor. The agricultural edge experiment presented in Chapter 3 confirmed that advection can be an important part of the scalar and energy budgets even in typical daytime conditions, and the modeling and scaling techniques applied in

  1. Field experiment provides ground truth for surface nuclear magnetic resonance measurement

    NASA Astrophysics Data System (ADS)

    Knight, Rosemary; Grunewald, Elliot; Irons, Trevor; Dlubac, Katherine; Song, Yiqiao; Bachman, Henry N.; Grau, Ben; Walsh, Dave; Abraham, Jared D.; Cannia, Jim

    2012-02-01

    The need for sustainable management of fresh water resources is one of the great challenges of the 21st century. Since most of the planet's liquid fresh water exists as groundwater, it is essential to develop non-invasive geophysical techniques to characterize groundwater aquifers. A field experiment was conducted in the High Plains Aquifer, central United States, to explore the mechanisms governing the non-invasive Surface NMR (SNMR) technology. We acquired both SNMR data and logging NMR data at a field site, along with lithology information from drill cuttings. This allowed us to directly compare the NMR relaxation parameter measured during logging, T2, to the relaxation parameter T2* measured using the SNMR method. The latter can be affected by inhomogeneity in the magnetic field, thus obscuring the link between the NMR relaxation parameter and the hydraulic conductivity of the geologic material. When the logging T2 data were transformed to pseudo- T2* data, by accounting for inhomogeneity in the magnetic field and instrument dead time, we found good agreement with T2* obtained from the SNMR measurement. These results, combined with the additional information about lithology at the site, allowed us to delineate the physical mechanisms governing the SNMR measurement. Such understanding is a critical step in developing SNMR as a reliable geophysical method for the assessment of groundwater resources.

  2. Field experiment provides ground truth for surface nuclear magnetic resonance measurement

    USGS Publications Warehouse

    Knight, R.; Grunewald, E.; Irons, T.; Dlubac, K.; Song, Y.; Bachman, H.N.; Grau, B.; Walsh, D.; Abraham, J.D.; Cannia, J.

    2012-01-01

    The need for sustainable management of fresh water resources is one of the great challenges of the 21st century. Since most of the planet's liquid fresh water exists as groundwater, it is essential to develop non-invasive geophysical techniques to characterize groundwater aquifers. A field experiment was conducted in the High Plains Aquifer, central United States, to explore the mechanisms governing the non-invasive Surface NMR (SNMR) technology. We acquired both SNMR data and logging NMR data at a field site, along with lithology information from drill cuttings. This allowed us to directly compare the NMR relaxation parameter measured during logging, T 2, to the relaxation parameter T 2 * measured using the SNMR method. The latter can be affected by inhomogeneity in the magnetic field, thus obscuring the link between the NMR relaxation parameter and the hydraulic conductivity of the geologic material. When the logging T 2 data were transformed to pseudo-T 2 * data, by accounting for inhomogeneity in the magnetic field and instrument dead time, we found good agreement with T 2 * obtained from the SNMR measurement. These results, combined with the additional information about lithology at the site, allowed us to delineate the physical mechanisms governing the SNMR measurement. Such understanding is a critical step in developing SNMR as a reliable geophysical method for the assessment of groundwater resources. Copyright 2012 by the American Geophysical Union.

  3. Assessing the use of an infrared spectrum hyperpixel array imager to measure temperature during additive and subtractive manufacturing

    NASA Astrophysics Data System (ADS)

    Whitenton, Eric; Heigel, Jarred; Lane, Brandon; Moylan, Shawn

    2016-05-01

    Accurate non-contact temperature measurement is important to optimize manufacturing processes. This applies to both additive (3D printing) and subtractive (material removal by machining) manufacturing. Performing accurate single wavelength thermography suffers numerous challenges. A potential alternative is hyperpixel array hyperspectral imaging. Focusing on metals, this paper discusses issues involved such as unknown or changing emissivity, inaccurate greybody assumptions, motion blur, and size of source effects. The algorithm which converts measured thermal spectra to emissivity and temperature uses a customized multistep non-linear equation solver to determine the best-fit emission curve. Emissivity dependence on wavelength may be assumed uniform or have a relationship typical for metals. The custom software displays residuals for intensity, temperature, and emissivity to gauge the correctness of the greybody assumption. Initial results are shown from a laser powder-bed fusion additive process, as well as a machining process. In addition, the effects of motion blur are analyzed, which occurs in both additive and subtractive manufacturing processes. In a laser powder-bed fusion additive process, the scanning laser causes the melt pool to move rapidly, causing a motion blur-like effect. In machining, measuring temperature of the rapidly moving chip is a desirable goal to develop and validate simulations of the cutting process. A moving slit target is imaged to characterize how the measured temperature values are affected by motion of a measured target.

  4. Evaluation of different field methods for measuring soil water infiltration

    NASA Astrophysics Data System (ADS)

    Pla-Sentís, Ildefonso; Fonseca, Francisco

    2010-05-01

    Soil infiltrability, together with rainfall characteristics, is the most important hydrological parameter for the evaluation and diagnosis of the soil water balance and soil moisture regime. Those balances and regimes are the main regulating factors of the on site water supply to plants and other soil organisms and of other important processes like runoff, surface and mass erosion, drainage, etc, affecting sedimentation, flooding, soil and water pollution, water supply for different purposes (population, agriculture, industries, hydroelectricity), etc. Therefore the direct measurement of water infiltration rates or its indirect deduction from other soil characteristics or properties has become indispensable for the evaluation and modelling of the previously mentioned processes. Indirect deductions from other soil characteristics measured under laboratory conditions in the same soils, or in other soils, through the so called "pedo-transfer" functions, have demonstrated to be of limited value in most of the cases. Direct "in situ" field evaluations have to be preferred in any case. In this contribution we present the results of past experiences in the measurement of soil water infiltration rates in many different soils and land conditions, and their use for deducing soil water balances under variable climates. There are also presented and discussed recent results obtained in comparing different methods, using double and single ring infiltrometers, rainfall simulators, and disc permeameters, of different sizes, in soils with very contrasting surface and profile characteristics and conditions, including stony soils and very sloping lands. It is concluded that there are not methods universally applicable to any soil and land condition, and that in many cases the results are significantly influenced by the way we use a particular method or instrument, and by the alterations in the soil conditions by the land management, but also due to the manipulation of the surface

  5. Efficient method for computing the maximum-likelihood quantum state from measurements with additive Gaussian noise.

    PubMed

    Smolin, John A; Gambetta, Jay M; Smith, Graeme

    2012-02-17

    We provide an efficient method for computing the maximum-likelihood mixed quantum state (with density matrix ρ) given a set of measurement outcomes in a complete orthonormal operator basis subject to Gaussian noise. Our method works by first changing basis yielding a candidate density matrix μ which may have nonphysical (negative) eigenvalues, and then finding the nearest physical state under the 2-norm. Our algorithm takes at worst O(d(4)) for the basis change plus O(d(3)) for finding ρ where d is the dimension of the quantum state. In the special case where the measurement basis is strings of Pauli operators, the basis change takes only O(d(3)) as well. The workhorse of the algorithm is a new linear-time method for finding the closest probability distribution (in Euclidean distance) to a set of real numbers summing to one.

  6. Development of standard measurement chain for full-field optical strain measurement methods

    NASA Astrophysics Data System (ADS)

    Salbut, Leszek; Kujawinska, Malgorzata; Patterson, Eann; Hack, Erwin; Burguete, Richard; Whelan, Maurice P.; Mendels, David A.

    2004-08-01

    Optical techniques for full-field displacement/strain measurement are a powerful set of tools for use in defining the performance, design optimization, reliability and safety of various types of components, products and machines. The quality of the measurement data generated by optical techniques is strongly dependent on the instrumentation and procedures. Thus, there is a significant need to develop standardized tests that are applicable across the spectrum of optical techniques of strain measurement. This requires the description of a common standard measurement chain including: (1) definition of standard physical and virtual materials; (2) gathering experimental or simulated primary data (fringe/image map); (3) deconvolution phase maps from these data (numerical procedures); (4) calculation of required physical quantities from phase maps (numerical procedures including data scaling). This scheme supports a calibration process for both instrumentation and procedures. Validation of this general methodology was performed using an example of displacement data gathered by grating interferometry followed by data processing scheme.

  7. Single-Molecule FRET Measurements in Additive-Enriched Aqueous Solutions.

    PubMed

    Kempe, Daryan; Cerminara, Michele; Poblete, Simón; Schöne, Antonie; Gabba, Matteo; Fitter, Jörg

    2017-01-03

    The addition of high amounts of chemical denaturants, salts, viscosity enhancers or macro-molecular crowding agents has an impact on the physical properties of buffer solutions. Among others, the (microscopic) viscosity, the refractive index, the dielectric constant, and the ionic strength can be affected. Here, we systematically evaluate the importance of solvent characteristics with respect to single-molecule FRET (smFRET) data. First, we present a confocal based method for the determination of fluorescence quantum yields to facilitate a fast characterization of smFRET-samples at sub-nM-concentrations. As a case study, we analyze smFRET data of structurally rigid, double-stranded DNA-oligonucleotides in aqueous buffer and in buffers with specific amounts of glycerol, guanidine hydrochloride (GdnHCl), and sodium chloride (NaCl) added. We show that the calculation of interdye distances, without taking into account solvent-induced spectral and photophysical changes of the labels, leads to deviations of up to 4 Å from the real interdye distances. Additionally, we demonstrate that electrostatic dye-dye repulsions are negligible for the interdye distance regime considered here (>50 Å). Finally, we use our approach to validate the further compaction of the already unfolded state of phosphoglycerate kinase (PGK) with decreasing denaturant concentrations, a mechanism known as coil-globule transition.

  8. Rates of False-Positive Classification Resulting From the Analysis of Additional Embedded Performance Validity Measures.

    PubMed

    Silk-Eglit, Graham M; Stenclik, Jessica H; Miele, Andrea S; Lynch, Julie K; McCaffrey, Robert J

    2015-01-01

    Several studies have documented improvements in the classification accuracy of performance validity tests (PVTs) when they are combined to form aggregated models. Fewer studies have evaluated the impact of aggregating additional PVTs and changing the classification threshold within these models. A recent Monte Carlo simulation demonstrated that to maintain a false-positive rate (FPR) of ≤.10, only 1, 4, 8, 10, and 15 PVTs should be analyzed at classification thresholds of failing at least 1, at least 2, at least 3, at least 4, and at least 5 PVTs, respectively. The current study sought to evaluate these findings with embedded PVTs in a sample of real-life litigants and to highlight a potential danger in analytic flexibility with embedded PVTs. Results demonstrated that to maintain an FPR of ≤.10, only 3, 7, 10, 14, and 15 PVTs should be analyzed at classification thresholds of failing at least 1, at least 2, at least 3, at least 4, and at least 5 PVTs, respectively. Analyzing more than these numbers of PVTs resulted in a dramatic increase in the FPR. In addition, in the most extreme case, flexibility in analyzing and reporting embedded PVTs increased the FPR by 67%. Given these findings, a more objective approach to analyzing and reporting embedded PVTs should be introduced.

  9. Ultraviolet and pulsed electric field treatments have additive effect on inactivation of E. coli in apple juice.

    PubMed

    Gachovska, T K; Kumar, S; Thippareddi, H; Subbiah, J; Williams, F

    2008-11-01

    Apple juice inoculated with Escherichia coli ATCC 23472 was processed continuously using either ultraviolet (UV), high-voltage pulsed electric field (PEF), or a combination of the PEF and UV treatment systems. Apple juice was pumped through either of the systems at 3 flow rates (8, 14, and 20 mL/min). E. coli was reduced by 3.46 log CFU/mL when exposed in a 50 cm length of UV treatment chamber at 8 mL/min (2.94 s treatment time with a product temperature increase of 13 degrees C). E. coli inactivation of 4.87 log CFU/mL was achieved with a peak electric field strength of 60 kV/cm and 11.3 pulses (average pulse width of 3.5 mus, product temperature increased to 52 degrees C). E. coli reductions resulting from a combination treatment of UV and PEF applied sequentially were evaluated. A maximum E. coli reduction of 5.35 log CFU/mL was achieved using PEF (electrical field strength of 60 kV/cm, specific energy of 162 J/mL, and 11.3 pulses) and UV treatments (length of 50 cm, treatment time of 2.94 s, and flow rate of 8 mL/min). An additive effect was observed for the combination treatments (PEF and UV), regardless of the order of treatment (P > 0.05). E. coli reductions of 5.35 and 5.30 log CFU/mL with PEF treatment (electrical field strength of 60 kV/cm, specific energy of 162 J/mL, and 11.3 pulses) followed by UV (length of 30 cm, treatment time of 1.8 s, and flow rate of 8 mL/min) and UV treatment followed by PEF (same treatment conditions), respectively. No synergistic effect was observed.

  10. Development of the laser absorption radiation thermometry technique to measure thermal diffusivity in addition to temperature

    NASA Astrophysics Data System (ADS)

    Levick, Andrew; Lobato, Killian; Edwards, Gordon

    2003-01-01

    A comparative technique based on photothermal radiometry has been developed to measure thermal diffusivity of semi-infinite targets with arbitrary geometry. The technique exploits the principle that the frequency response of the temperature modulation induced by a periodic modulated heating source (in this case a laser spot) scales with thermal diffusivity. To demonstrate this technique, a photothermal radiometer has been developed, which detects modulated thermal radiance at a wavelength of 2 μm due to a small temperature modulation induced on the target surface by a modulated erbium fiber laser of power 1 W. Two frequency responses were measured for platinum and oxidized Inconel 600 targets (the frequency response is a scan of the amplitude of the modulated thermal radiance over laser modulation frequency). Scaling the two responses with respect to frequency gives a ratio of thermal diffusivities Dplatinum/DInconel of 4.45(33) which compares with a literature value of 4.46(50). The aim is to combine this technique with laser absorption radiation thermometry to produce multithermal property instrument for measuring "industrial" targets.

  11. Testing the Need for Replication of Eddy Covariance Carbon Dioxide Flux Measurements over Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Taylor, A. M.; Amiro, B. D.; Gervais, M.

    2015-12-01

    The eddy covariance method directly measures carbon dioxide (CO2) fluxes for long periods of time and with footprints up to hundreds of meters in size. Any ecosystem process that alters how gases and energy move between the atmosphere and soil/vegetation can affect these fluxes. Eddy covariance is vulnerable to systematic errors and uncertainy, particular through relying on assumptions about surface characteristics. Additionally, spatial variation within a site can cause more uncertainty in these measurements and lack of replication in many eddy covariance studies makes statistical analysis of carbon fluxes challenging. We tested if there are significant differences between co-located and simultaneous CO2 flux measurements over a uniform crop surface, and if the differences increase if we measure different flux footprint areas over the same field. During the summer of 2014, three matched instrumented 2.5-m high towers were co-located and then periodically separated by moving at 50 m intervals along a north-south transect on an alfalfa/trefoil field and a spring wheat field in Southern Manitoba, Canada to compare CO­2 fluxes. Georeferenced leaf area index measurements were taken in 50 m grid of each field to establish uniformity of the source/sink within a footprint. Diurnal differences of similar magnitude in the CO2 ­fluxes were found in both the co-located experiment and the spatially separated intervals. Despite rigorous calibration during the experiment, some differences were caused by the measurement systems rather than by variation within the field. Interpretation of the spatial variation in leaf area index is being used to determine the contribution caused by difference in source/sink contributions to the flux footprint areas when the towers were spatially separated.

  12. Field measurements of boundary-layer flows in ventilated rooms

    SciTech Connect

    Zhang, J.S.; Shaw, C.Y.; MacDonald, R.A.; Nguyen-Thi, L.C.; Kerr, G.

    1995-12-31

    Profiles of air velocity and turbulent kinetic energy near the surfaces of walls, ceilings, floors, and furnishings were measured under field conditions for four space layouts of an office building: a partitioned office room, a single office room, a small conference room, and a computer room. Three types of flows near the surfaces were identified based on the measured data: (1) near-stagnant flow that had mean velocities and turbulent kinetic energies of less than 0.05 {+-} 0.025 m/s (10 {+-} 5 fpm) and 0.001 {+-} 0.001 (m/s){sup 2} (38.75 {+-} 38.75 (fpm){sup 2}), respectively; (2) weak turbulence flow that had mean velocities and turbulent kinetic energies from 0.05 {+-} 0.025 to 0.25 {+-} 0.05 m/s (10 {+-} 5 to 50 {+-} 10 fpm) and from 0.001 {+-} 0.001 to 0.01 {+-} 0.002 (m/s){sup 2} (38.75 {+-} 38.75 to 387.5 {+-} 77.5 [fpm]{sup 2}), respectively. The results are useful for establishing realistic airflow conditions in testing and modeling contaminant emission from building materials and indoor furnishings.

  13. Interferometric field of view measurements at the VLTI

    NASA Astrophysics Data System (ADS)

    Hummel, Christian A.; Le Bouquin, Jean-Baptiste; Merand, Antoine

    2016-07-01

    In August 2014 we performed technical observations at the VLTI with the AMBER and PIONIER beam combiners to measure the interferometric field of view (FOV). As targets we included binaries with component separations between 100 and 300 mas, for which orbits and/or interferometric speckle measurements are available from the Washington Double Star databases or from the literature. The analysis included effects such as bandwidth and time smearing of the interferograms, and photometric attenuation due to the seeing and image quality based on a new formalism of the ESO Exposure Time Calculators. We also consulted the literature for results of interferometric surveys such as the SMASH survey.1 to estimate the effective FOV for these instruments. Based on our analysis, we conclude that emission outside a FOV diameter of 160 mas will be significantly suppressed if not completely invisible. These results provide important information as to the size of the source structure to be included when modeling interferometric data obtained with these instruments.

  14. Electric Field Change Measurements of a Terrestrial Gamma Ray Flash

    NASA Astrophysics Data System (ADS)

    Marshall, Thomas; Karunarathne, Sumedhe; Stolzenburg, Maribeth

    2016-04-01

    Cummer et al. [GRL, 2014] reported on two terrestrial gamma ray flashes (TGFs) detected by the Gamma ray Burst Monitor (GBM) on the Fermi satellite. At a range of 632 km we detected an electric field change pulse associated with the first of these TGFs. The sensor bandwidth was 0.16 Hz - 2.6 MHz and was sampled at 5 MS/s. The measured zero-to-peak amplitude was 3.1 V/m. Assuming a 1/R range dependence, the amplitude range normalized to 100 km would be about 20 V/m. However, a little more than half of the path from the TGF to the sensor was over land rather than ocean, which should cause the attenuation to be greater than 1/R. Based on recent measurements of Kolmasova et al. (2015 AGU Fall Meeting), we estimate that the real peak amplitude was 40 - 50 V/m. The detected pulse was bipolar with a leading positive peak and had an overall duration of about 50 μs; these characteristics are typical of initial breakdown pulses (IBPs) that occur at the beginning of intracloud (IC) flashes. However, the pulse amplitude is an order of magnitude larger than typical IBPs. These data support the notion that IBPs of IC flashes cause TGFs [e.g., Shao et al., JGR 2010; Lu et al., GRL 2010; Cummer et al., GRL 2014].

  15. Study of Wood Plastic Composites elastic behaviour using full field measurements

    NASA Astrophysics Data System (ADS)

    Ben Mbarek, T.; Robert, L.; Hugot, F.; Orteu, J. J.; Sammouda, H.; Graciaa, A.; Charrier, B.

    2010-06-01

    In this study, the mechanical properties and microstructure of HDPE/wood fibre composites are investigated. The four-point bending and tensile behaviour of Wood Plastic Composite (WPC) with or without additive are studied by using full-field strain measurements by 3-D Digital Image Correlation (3-D DIC). A non-linear behaviour is shown. The modulus of elasticity (MOE) is calculated as the tangent at zero strain of a Maxwell-Bingham model fitted onto experimental data. Four-point bending tests are analyzed thanks to the spatial standard deviation of the longitudinal strain field to determine the degree of heterogeneity. Cyclic tensile tests have been performed in order to analyze the damage of the material. Moreover, Scanning Electron Microscope (SEM) is used to characterize the morphology of the wood fibre/HDPE matrix interface for specimens with maleic anhydride modified polyethylene additive (MAPE).

  16. Modest additive effects of integrated vector control measures on malaria prevalence and transmission in western Kenya

    PubMed Central

    2013-01-01

    Background The effect of integrating vector larval intervention on malaria transmission is unknown when insecticide-treated bed-net (ITN) coverage is very high, and the optimal indicator for intervention evaluation needs to be determined when transmission is low. Methods A post hoc assignment of intervention-control cluster design was used to assess the added effect of both indoor residual spraying (IRS) and Bacillus-based larvicides (Bti) in addition to ITN in the western Kenyan highlands in 2010 and 2011. Cross-sectional, mass parasite screenings, adult vector populations, and cohort of active case surveillance (ACS) were conducted before and after the intervention in three study sites with two- to three-paired intervention-control clusters at each site each year. The effect of larviciding, IRS, ITNs and other determinants of malaria risk was assessed by means of mixed estimating methods. Results Average ITN coverage increased from 41% in 2010 to 92% in 2011 in the study sites. IRS intervention had significant added impact on reducing vector density in 2010 but the impact was modest in 2011. The effect of IRS on reducing parasite prevalence was significant in 2011 but was seasonal specific in 2010. ITN was significantly associated with parasite densities in 2010 but IRS application was significantly correlated with reduced gametocyte density in 2011. IRS application reduced about half of the clinical malaria cases in 2010 and about one-third in 2011 compare to non-intervention areas. Conclusion Compared with a similar study conducted in 2005, the efficacy of the current integrated vector control with ITN, IRS, and Bti reduced three- to five-fold despite high ITN coverage, reflecting a modest added impact on malaria transmission. Additional strategies need to be developed to further reduce malaria transmission. PMID:23870708

  17. Statistical analysis of personal radiofrequency electromagnetic field measurements with nondetects.

    PubMed

    Röösli, Martin; Frei, Patrizia; Mohler, Evelyn; Braun-Fahrländer, Charlotte; Bürgi, Alfred; Fröhlich, Jürg; Neubauer, Georg; Theis, Gaston; Egger, Matthias

    2008-09-01

    Exposimeters are increasingly applied in bioelectromagnetic research to determine personal radiofrequency electromagnetic field (RF-EMF) exposure. The main advantages of exposimeter measurements are their convenient handling for study participants and the large amount of personal exposure data, which can be obtained for several RF-EMF sources. However, the large proportion of measurements below the detection limit is a challenge for data analysis. With the robust ROS (regression on order statistics) method, summary statistics can be calculated by fitting an assumed distribution to the observed data. We used a preliminary sample of 109 weekly exposimeter measurements from the QUALIFEX study to compare summary statistics computed by robust ROS with a naïve approach, where values below the detection limit were replaced by the value of the detection limit. For the total RF-EMF exposure, differences between the naïve approach and the robust ROS were moderate for the 90th percentile and the arithmetic mean. However, exposure contributions from minor RF-EMF sources were considerably overestimated with the naïve approach. This results in an underestimation of the exposure range in the population, which may bias the evaluation of potential exposure-response associations. We conclude from our analyses that summary statistics of exposimeter data calculated by robust ROS are more reliable and more informative than estimates based on a naïve approach. Nevertheless, estimates of source-specific medians or even lower percentiles depend on the assumed data distribution and should be considered with caution.

  18. Results from laboratory and field testing of nitrate measuring spectrophotometers

    USGS Publications Warehouse

    Snazelle, Teri T.

    2015-01-01

    In Phase II, the analyzers were deployed in field conditions at three diferent USGS sites. The measured nitrate concentrations were compared to discrete (reference) samples analyzed by the Direct UV method on a Shimadzu UV1800 bench top spectrophotometer, and by the National Environmental Methods Index (NEMI) method I-2548-11 at the USGS National Water Quality Laboratory. The first deployment at USGS site 0249620 on the East Pearl River in Hancock County, Mississippi, tested the ability of the TriOs ProPs (10-mm path length), Hach NITRATAX (5 mm), Satlantic SUNA (10 mm), and the S::CAN Spectro::lyser (5 mm) to accurately measure low-level (less than 2 mg-N/L) nitrate concentrations while observing the effect turbidity and colored dissolved organic matter (CDOM) would have on the analyzers' measurements. The second deployment at USGS site 01389005 Passaic River below Pompton River at Two Bridges, New Jersey, tested the analyzer's accuracy in mid-level (2-8 mg-N/L) nitrate concentrations. This site provided the means to test the analyzers' performance in two distinct matrices—the Passaic and the Pompton Rivers. In this deployment, three instruments tested in Phase I (TriOS, Hach, and SUNA) were deployed with the S::CAN Spectro::lyser (35 mm) already placed by the New Jersey Water Science Center (WSC). The third deployment at USGS site 05579610 Kickapoo Creek at 2100E Road near Bloomington, Illinois, tested the ability of the analyzers to measure high nitrate concentrations (greater than 8 mg-N/L) in turbid waters. For Kickapoo Creek, the HIF provided the TriOS (10 mm) and S::CAN (5 mm) from Phase I, and a SUNA V2 (5 mm) to be deployed adjacent to the Illinois WSC-owned Hach (2 mm). A total of 40 discrete samples were collected from the three deployment sites and analyzed. The nitrate concentration of the samples ranged from 0.3–22.2 mg-N/L. The average absolute difference between the TriOS measurements and discrete samples was 0.46 mg-N/L. For the combined data

  19. Field measurement of basal forces generated by erosive debris flows

    USGS Publications Warehouse

    McCoy, S.W.; Tucker, G.E.; Kean, J.W.; Coe, J.A.

    2013-01-01

    It has been proposed that debris flows cut bedrock valleys in steeplands worldwide, but field measurements needed to constrain mechanistic models of this process remain sparse due to the difficulty of instrumenting natural flows. Here we present and analyze measurements made using an automated sensor network, erosion bolts, and a 15.24 cm by 15.24 cm force plate installed in the bedrock channel floor of a steep catchment. These measurements allow us to quantify the distribution of basal forces from natural debris‒flow events that incised bedrock. Over the 4 year monitoring period, 11 debris‒flow events scoured the bedrock channel floor. No clear water flows were observed. Measurements of erosion bolts at the beginning and end of the study indicated that the bedrock channel floor was lowered by 36 to 64 mm. The basal force during these erosive debris‒flow events had a large‒magnitude (up to 21 kN, which was approximately 50 times larger than the concurrent time‒averaged mean force), high‒frequency (greater than 1 Hz) fluctuating component. We interpret these fluctuations as flow particles impacting the bed. The resulting variability in force magnitude increased linearly with the time‒averaged mean basal force. Probability density functions of basal normal forces were consistent with a generalized Pareto distribution, rather than the exponential distribution that is commonly found in experimental and simulated monodispersed granular flows and which has a lower probability of large forces. When the bed sediment thickness covering the force plate was greater than ~ 20 times the median bed sediment grain size, no significant fluctuations about the time‒averaged mean force were measured, indicating that a thin layer of sediment (~ 5 cm in the monitored cases) can effectively shield the subjacent bed from erosive impacts. Coarse‒grained granular surges and water‒rich, intersurge flow had very similar basal force distributions despite

  20. Cl2 Measurements in Polluted Coastal Air Using a Br- Addition CIMS Technique

    NASA Astrophysics Data System (ADS)

    Lawler, M. J.; Saltzman, E. S.

    2008-12-01

    Molecular chlorine (Cl2) was measured in ambient air using chemical ionization mass spectrometry (CIMS) with Br- as a reagent ion. Ionization was carried out by adding CHBr3 to ambient air and flowing the gas mixture through a 63Ni ion source maintained at 300 Torr. The resulting Cl2Br- adduct was collisionally dissociated in a triple quadrupole mass spectrometer and detected as Cl-. Ambient Cl2 measurements were made at Irvine, CA, from August 1-8, 2008. Air was drawn to the instrument from outside via a ~4m long laminar flow inlet. Inlet and instrument blanks were assessed by passing ambient air through carbonate-coated glass wool, and the instrument was calibrated with a Cl2 permeation tube. During this study, the mean detection limit for Cl2 was estimated at approximately 2 ppt. Cl2 showed a diel cycle on the days it was detectable, with nighttime mixing ratios up to about 15 ppt and daytime values of a few ppt or less. A rapid decrease in Cl2 in surface air was observed overnight in association with stagnation of the nocturnal surface layer.

  1. Field measurements and neural network modeling of water quality parameters

    NASA Astrophysics Data System (ADS)

    Qishlaqi, Afishin; Kordian, Sediqeh; Parsaie, Abbas

    2017-01-01

    Rivers are one of the main resources for water supplying the agricultural, industrial, and urban use; therefore, unremitting surveying the quality of them is necessary. Recently, artificial neural networks have been proposed as a powerful tool for modeling and predicting the water quality parameters in natural streams. In this paper, to predict water quality parameters of Tireh River located at South West of Iran, a multilayer neural network model (MLP) was developed. The T.D.S, Ec, pH, HCO3, Cl, Na, So4, Mg, and Ca as main parameters of water quality parameters were measured and predicted using the MLP model. The architecture of the proposed MLP model included two hidden layers that at the first and second hidden layers, eight and six neurons were considered. The tangent sigmoid and pure-line functions were selected as transfer function for the neurons in hidden and output layers, respectively. The results showed that the MLP model has suitable performance to predict water quality parameters of Tireh River. For assessing the performance of the MLP model in the water quality prediction along the studied area, in addition to existing sampling stations, another 14 stations along were considered by authors. Evaluating the performance of developed MLP model to map relation between the water quality parameters along the studied area showed that it has suitable accuracy and minimum correlation between the results of MLP model and measured data was 0.85.

  2. Evaluation of the Geomagnetic Field Models based on Magnetometer Measurements for Satellite's Attitude Determination System

    NASA Astrophysics Data System (ADS)

    Cilden, Demet; Kaymaz, Zerefsan; Hajiyev, Chingiz

    2016-07-01

    Magnetometers are common attitude determination sensors for small satellites at low Earth orbit; therefore, magnetic field model of the Earth is necessary to estimate the satellite's attitude angles. Difference in the components of the magnetic field vectors -mostly used as unit vector. Therefore the angle between them (model and measurement data) affects the estimation accuracy of the satellite's attitude. In this study, geomagnetic field models are compared with satellite magnetic field observations in order to evaluate the models using the magnetometer results with high accuracy. For attitude determination system, IGRF model is used in most of the cases but the difference between the sensor and model increases when the geomagnetic activity occurs. Hence, several models including the empirical ones using the external variations in the Earth's geomagnetic field resulting from the solar wind and interplanetary magnetic field are of great importance in determination of the satellite's attitude correctly. IGRF model describes the internal-part of the geomagnetic field, on the other hand candidate models to IGRF, such as recently developed POMME-6 model based on Champ data, CHAOS-5 (CHAmp, Oersted, Swarm), T89 (Tsyganenko's model), include simple parameterizations of external fields of magnetospheric sources in addition to the internal field especially for low Earth orbiting satellites. Those models can be evaluated to see noticeable difference on extraterrestrial field effects on satellite's attitude determination system changing with its height. The comparisons are made between the models and observations and between the models under various magnetospheric activities. In this study, we will present our preliminary results from the comparisons and discuss their implications from the satellite attitude perspective.

  3. Synchrotron microimaging technique for measuring the velocity fields of real blood flows

    SciTech Connect

    Lee, Sang-Joon; Kim, Guk Bae

    2005-03-15

    Angiography and Doppler methods used for diagnosing vascular diseases give information on the shape of blood vessels and pointwise blood speed but do not provide detailed information on the flow fields inside the blood vessels. In this study, we developed a method for visualizing blood flow by using coherent synchrotron x rays. This method, which does not require the addition of any contrast agent or tracer particles, visualizes the flow pattern of blood by enhancing the diffraction and interference characteristics of the blood cells. This was achieved by optimizing the sample- (blood) to-detector (charge-coupled device camera) distance and the sample thickness. The proposed method was used to extract quantitative velocity field information from blood flowing inside an opaque microchannel by applying a two-frame particle image velocimetry algorithm to enhanced x-ray images of the blood flow. The measured velocity field data showed a flow structure typical of flow in a macrochannel.

  4. Neutron measurements of stresses in a test artifact produced by laser-based additive manufacturing

    SciTech Connect

    Gnäupel-Herold, Thomas; Slotwinski, John; Moylan, Shawn

    2014-02-18

    A stainless steel test artifact produced by Direct Metal Laser Sintering and similar to a proposed standardized test artifact was examined using neutron diffraction. The artifact contained a number of structures with different aspect ratios pertaining to wall thickness, height above base plate, and side length. Through spatial resolutions of the order of one millimeter the volumetric distribution of stresses in several was measured. It was found that the stresses peak in the tensile region around 500 MPa near the top surface, with balancing compressive stresses in the interior. The presence of a support structure (a one millimeter high, thin walled, hence weaker, lattice structure deposited on the base plate, followed by a fully dense AM structure) has only minor effects on the stresses.

  5. Time- and isomer-resolved measurements of sequential addition of acetylene to the propargyl radical

    DOE PAGES

    Savee, John D.; Selby, Talitha M.; Welz, Oliver; ...

    2015-10-06

    Soot formation in combustion is a complex process in which polycyclic aromatic hydrocarbons (PAHs) are believed to play a critical role. Recent works concluded that three consecutive additions of acetylene (C2H2) to propargyl (C3H3) create a facile route to the PAH indene (C9H8). However, the isomeric forms of C5H5 and C7H7 intermediates in this reaction sequence are not known. We directly investigate these intermediates using time- and isomer-resolved experiments. Both the resonance stabilized vinylpropargyl (vp-C5H5) and 2,4-cyclopentadienyl (c-C5H5) radical isomers of C5H5 are produced, with substantially different intensities at 800 K vs 1000 K. In agreement with literature master equationmore » calculations, we find that c-C5H5 + C2H2 produces only the tropyl isomer of C7H7 (tp-C7H7) below 1000 K, and that tp-C7H7 + C2H2 terminates the reaction sequence yielding C9H8 (indene) + H. Lastly, this work demonstrates a pathway for PAH formation that does not proceed through benzene.« less

  6. A New Method for Finding Optical Aberrations on the Basis of Analysis of the Object Hologram Without Additional Measurements

    NASA Astrophysics Data System (ADS)

    Matkivsky, V. A.; Moiseev, A. A.; Shilyagin, P. A.; Shabanov, D. V.; Gelikonov, G. V.; Gelikonov, V. M.

    2016-11-01

    We propose a new method of compensating for the wavefront aberrations during the image processing. The method employs the digital-holography potential. The developed algorithms allow one to find the wavefront distortions caused by the optical-path nonuniformities during the interference recording of images without additional measurements (i.e., without using the reference point source and measuring the wavefront distortions). The possibility of decreasing the wavefront aberrations from tens to several radians using digital methods is demonstrated.

  7. Discharge rate measurements for Micromegas detectors in the presence of a longitudinal magnetic field

    SciTech Connect

    B. Moreno, S. Aune, J. Ball, G. Charles, A. Giganon, P. Konczykowski, C. Lahonde-Hamdoun, H. Moutarde, S. Procureur, F. Sabatie

    2011-10-01

    We present first discharge rate measurements for Micromegas detectors in the presence of a high longitudinal magnetic field in the GeV kinematical region. Measurements were performed by using two Micromegas detectors and a photon beam impinging a CH{sub 2} target in the Hall B of the Jefferson Laboratory. One detector was equipped with an additional GEM foil, and a reduction of the discharge probability by two orders of magnitude compared to the stand-alone Micromegas was observed. The detectors were p laced in the FROST solenoid providing a longitudinal magnetic field up to 5T. It allowed for precise measurements of the discharge probability dependence with a diffusion-reducing magnetic field. Between 0 and 5T, the discharge probability increased by a factor of 10 for polar angles between 19{degrees} and 34{degrees}. A GEANT4-based simulation developed for sparking rate calculation was calibrated against these data in order to predict the sparking rate in a high longitudinal magnetic field environment. This simulati on is then used to investigate the possible use of Micromegas in the Forward Vertex Tracker (FVT) of the future CLAS12 spectrometer. In the case of the FVT a sparking rate of 1Hz per detector was obtained at the anticipated CLAS12 luminosity.

  8. Time- and isomer-resolved measurements of sequential addition of acetylene to the propargyl radical

    SciTech Connect

    Savee, John D.; Selby, Talitha M.; Welz, Oliver; Taatjes, Craig A.; Osborn, David L.

    2015-10-06

    Soot formation in combustion is a complex process in which polycyclic aromatic hydrocarbons (PAHs) are believed to play a critical role. Recent works concluded that three consecutive additions of acetylene (C2H2) to propargyl (C3H3) create a facile route to the PAH indene (C9H8). However, the isomeric forms of C5H5 and C7H7 intermediates in this reaction sequence are not known. We directly investigate these intermediates using time- and isomer-resolved experiments. Both the resonance stabilized vinylpropargyl (vp-C5H5) and 2,4-cyclopentadienyl (c-C5H5) radical isomers of C5H5 are produced, with substantially different intensities at 800 K vs 1000 K. In agreement with literature master equation calculations, we find that c-C5H5 + C2H2 produces only the tropyl isomer of C7H7 (tp-C7H7) below 1000 K, and that tp-C7H7 + C2H2 terminates the reaction sequence yielding C9H8 (indene) + H. Lastly, this work demonstrates a pathway for PAH formation that does not proceed through benzene.

  9. Unraveling brackish groundwater - surface water interaction in an agricultural field using direct measurements at the field scale

    NASA Astrophysics Data System (ADS)

    Delsman, Joost; Waterloo, Maarten; Groen, Michel; Groen, Koos

    2014-05-01

    Understanding the interaction between groundwater and surface water is important for a myriad of reasons, including flow forecasting, nutrient transport, and water allocation for agriculture and other water users. This understanding is especially important in deep polder areas in the Netherlands, where brackish groundwater seepage (upward flowing regional groundwater) results in a significant salt load to surface water, and may damage crops if salts reach the rootzone in dry summers. Research on groundwater - surface water interaction historically focused on relatively pristine headwater catchments, only recently shifting somewhat to agricultural catchments. The latter pose specific research challenges, as agricultural activities and active water management can have a significant influence on hydrology. A brackish seepage flux, with a different density as precipitation, may significantly influence flow paths to surface water. Research on this specific topic is, however, lacking. We therefore investigated the interaction between groundwater and surface water in an agricultural catchment with a significant brackish seepage flux. In addition, we investigated the effects of intake of fresh water during periods of precipitation deficits, a common management strategy in lowland regions. We instrumented an agricultural ditch to enable direct, 15 min interval measurements of water fluxes and salinity to both agricultural drains and the ditch separately. These measurements are supported by piezometer nests, soil moisture sensors, temperature sensors, geophysics and a meteorological tower. Measurements focused on the summer period and were taken during two measurement periods: May 2012 - November 2012, and April 2013 - October 2013. Our measurements allowed for a direct, high-frequency separation of hydrological flow routes on this agricultural field between flow to agricultural drains and the ditch. The salinity of seepage water allowed for a relatively easy separation of

  10. Measuring Productive Elements of Multi-Word Phrase Vocabulary Knowledge among Children with English as an Additional or Only Language

    ERIC Educational Resources Information Center

    Smith, Sara A.; Murphy, Victoria A.

    2015-01-01

    Vocabulary plays a critical role in language and reading development for children, particularly those learning English as an additional language (EAL) (Stahl & Nagy, 2006). Previous research on vocabulary has mainly focused on measuring individual words without considering multi-word phrase knowledge, despite evidence that these items occur…

  11. Direct measurement of the upper critical field in cuprate superconductors

    PubMed Central

    Grissonnanche, G.; Cyr-Choinière, O.; Laliberté, F.; René de Cotret, S.; Juneau-Fecteau, A.; Dufour-Beauséjour, S.; Delage, M. -È.; LeBoeuf, D.; Chang, J.; Ramshaw, B. J.; Bonn, D. A.; Hardy, W. N.; Liang, R.; Adachi, S.; Hussey, N. E.; Vignolle, B.; Proust, C.; Sutherland, M.; Krämer, S.; Park, J. -H.; Graf, D.; Doiron-Leyraud, N.; Taillefer, Louis

    2014-01-01

    In the quest to increase the critical temperature Tc of cuprate superconductors, it is essential to identify the factors that limit the strength of superconductivity. The upper critical field Hc2 is a fundamental measure of that strength, yet there is no agreement on its magnitude and doping dependence in cuprate superconductors. Here we show that the thermal conductivity can be used to directly detect Hc2 in the cuprates YBa2Cu3Oy, YBa2Cu4O8 and Tl2Ba2CuO6+δ, allowing us to map out Hc2 across the doping phase diagram. It exhibits two peaks, each located at a critical point where the Fermi surface of YBa2Cu3Oy is known to undergo a transformation. Below the higher critical point, the condensation energy, obtained directly from Hc2, suffers a sudden 20-fold collapse. This reveals that phase competition—associated with Fermi-surface reconstruction and charge-density-wave order—is a key limiting factor in the superconductivity of cuprates. PMID:24518054

  12. Wake Vortex Field Measurement Program at Memphis, Tennessee: Data Guide

    NASA Technical Reports Server (NTRS)

    Campbell, S. D.; Dasey, T. J.; Freehart, R. E.; Heinrichs, R. M.; Mathews, M. P.; Perras, G. H.; Rowe, G. S.

    1997-01-01

    Eliminating or reducing current restrictions in the air traffic control system due to wake vortex considerations would yield increased capacity, decreased delays, and cost savings. Current wake vortex separation standards are widely viewed as very conservative under most conditions. However, scientific uncertainty about wake vortex behavior under different atmospheric conditions remains a barrier to development of an adaptive vortex spacing system. The objective of the wake vortex field measurement efforts during December, 1994 and August, 1995 at Memphis, TN were to record wake vortex behavior for varying atmospheric conditions and types of aircraft. This effort is part of a larger effort by the NASA Langley Research Center to develop an Aircraft Vortex Spacing System (AVOSS) as an element of the Terminal Area Productivity (TAP) program. The TAP program is being performed in concert with the FAA Terminal Air Traffic Control Automation (TATCA) program and ATC Automation. Wake vortex behavior was observed using a mobile continuous-wave (CW) coherent laser Doppler radar (lidar) developed at Lincoln Laboratory. This lidar features a number of improvements over previous systems, including the first-ever demonstration of an automatic wake vortex detection and tracking algorithm.

  13. Distance measurement based on light field geometry and ray tracing.

    PubMed

    Chen, Yanqin; Jin, Xin; Dai, Qionghai

    2017-01-09

    In this paper, we propose a geometric optical model to measure the distances of object planes in a light field image. The proposed geometric optical model is composed of two sub-models based on ray tracing: object space model and image space model. The two theoretic sub-models are derived on account of on-axis point light sources. In object space model, light rays propagate into the main lens and refract inside it following the refraction theorem. In image space model, light rays exit from emission positions on the main lens and subsequently impinge on the image sensor with different imaging diameters. The relationships between imaging diameters of objects and their corresponding emission positions on the main lens are investigated through utilizing refocusing and similar triangle principle. By combining the two sub-models together and tracing light rays back to the object space, the relationships between objects' imaging diameters and corresponding distances of object planes are figured out. The performance of the proposed geometric optical model is compared with existing approaches using different configurations of hand-held plenoptic 1.0 cameras and real experiments are conducted using a preliminary imaging system. Results demonstrate that the proposed model can outperform existing approaches in terms of accuracy and exhibits good performance at general imaging range.

  14. Velocity field measurements in the wake of a propeller model

    NASA Astrophysics Data System (ADS)

    Mukund, R.; Kumar, A. Chandan

    2016-10-01

    Turboprop configurations are being revisited for the modern-day regional transport aircrafts for their fuel efficiency. The use of laminar flow wings is an effort in this direction. One way to further improve their efficiency is by optimizing the flow over the wing in the propeller wake. Previous studies have focused on improving the gross aerodynamic characteristics of the wing. It is known that the propeller slipstream causes early transition of the boundary layer on the wing. However, an optimized design of the propeller and wing combination could delay this transition and decrease the skin friction drag. Such a wing design would require the detailed knowledge of the development of the slipstream in isolated conditions. There are very few studies in the literature addressing the requirements of transport aircraft having six-bladed propeller and cruising at a high propeller advance ratio. Low-speed wind tunnel experiments have been conducted on a powered propeller model in isolated conditions, measuring the velocity field in the vertical plane behind the propeller using two-component hot-wire anemometry. The data obtained clearly resolved the mean velocity, the turbulence, the ensemble phase averages and the structure and development of the tip vortex. The turbulence in the slipstream showed that transition could be close to the leading edge of the wing, making it a fine case for optimization. The development of the wake with distance shows some interesting flow features, and the data are valuable for flow computation and optimization.

  15. Effects of Electromagnetic Fields on Automated Blood Cell Measurements.

    PubMed

    Vagdatli, Eleni; Konstandinidou, Vasiliki; Adrianakis, Nikolaos; Tsikopoulos, Ioannis; Tsikopoulos, Alexios; Mitsopoulou, Kyriaki

    2014-08-01

    The aim of this study is to investigate whether the electromagnetic fields associated with mobile phones and/or laptops interfere with blood cell counts of hematology analyzers. Random blood samples were analyzed on an Aperture Impedance hematology analyzer. The analysis was performed in four ways: (A) without the presence of any mobile phone or portable computer in use, (B) with mobile phones in use (B1: one mobile, B4: four mobiles), (C) with portable computers (laptops) in use (C1: one laptop, C3: three laptops), and (D) with four mobile phones and three laptops in use simultaneously. The results obtained demonstrated a statistically significant decrease in neutrophil, erythrocyte, and platelet count and an increase in lymphocyte count, mean corpuscular volume, and red blood cell distribution width, notably in the B4 group. Despite this statistical significance, in clinical practice, only the red blood cell reduction could be taken into account, as the mean difference between the A and B4 group was 60,000 cells/µL. In group D, the analyzer gave odd results after 11 measurements and finally stopped working. The combined and multiple use of mobile phones and computers affects the function of hematology analyzers, leading to false results. Consequently, the use of such electronic devices must be avoided.

  16. Simultaneous electric-field measurements on nearby balloons.

    NASA Technical Reports Server (NTRS)

    Mozer, F. S.

    1972-01-01

    Electric-field payloads were flown simultaneously on two balloons from Great Whale River, Canada, on September 21, 1971, to provide data at two points in the upper atmosphere that differed in altitude by more than one atmospheric density scale height and in horizontal position by 30-140 km. The altitude dependences in the two sets of data prove conclusively that the vertical electric field at balloon altitudes stems from fair-weather atmospheric electricity sources and that the horizontal fields are mapped down ionospheric fields, since the weather-associated horizontal fields were smaller than 2 mV/m.

  17. Development of Field Excavator with Embedded Force Measurement

    NASA Technical Reports Server (NTRS)

    Johnson, K.; Creager, C.; Izadnegahdar, A.; Bauman, S.; Gallo, C.; Abel, P.

    2012-01-01

    A semi-intelligent excavation mechanism was developed for use with the NASA-built Centaur 2 rover prototype. The excavator features a continuously rotatable large bucket supported between two parallel arms, both of which share a single pivot axis near the excavator base attached to the rover. The excavator is designed to simulate the collection of regolith, such as on the Moon, and to dump the collected soil into a hopper up to one meter tall for processing to extract oxygen. Because the vehicle can be autonomous and the terrain is generally unknown, there is risk of damaging equipment or using excessive power when attempting to extract soil from dense or rocky terrain. To minimize these risks, it is critical for the rover to sense the digging forces and adjust accordingly. It is also important to understand the digging capabilities and limitations of the excavator. This paper discusses the implementation of multiple strain gages as an embedded force measurement system in the excavator's arms. These strain gages can accurately measure and resolve multi-axial forces on the excavator. In order to validate these sensors and characterize the load capabilities, a series of controlled excavation tests were performed at Glenn Research Center with the excavator at various depths and cut angles while supported by a six axis load cell. The results of these tests are both compared to a force estimation model and used for calibration of the embedded strain gages. In addition, excavation forces generated using two different types of bucket edge (straight vs. with teeth) were compared.

  18. Additional Value of CH₄ Measurement in a Combined (13)C/H₂ Lactose Malabsorption Breath Test: A Retrospective Analysis.

    PubMed

    Houben, Els; De Preter, Vicky; Billen, Jaak; Van Ranst, Marc; Verbeke, Kristin

    2015-09-07

    The lactose hydrogen breath test is a commonly used, non-invasive method for the detection of lactose malabsorption and is based on an abnormal increase in breath hydrogen (H₂) excretion after an oral dose of lactose. We use a combined (13)C/H₂ lactose breath test that measures breath (13)CO₂ as a measure of lactose digestion in addition to H₂ and that has a better sensitivity and specificity than the standard test. The present retrospective study evaluated the results of 1051 (13)C/H₂ lactose breath tests to assess the impact on the diagnostic accuracy of measuring breath CH₄ in addition to H₂ and (13)CO₂. Based on the (13)C/H₂ breath test, 314 patients were diagnosed with lactase deficiency, 138 with lactose malabsorption or small bowel bacterial overgrowth (SIBO), and 599 with normal lactose digestion. Additional measurement of CH₄ further improved the accuracy of the test as 16% subjects with normal lactose digestion and no H₂-excretion were found to excrete CH₄. These subjects should have been classified as subjects with lactose malabsorption or SIBO. In conclusion, measuring CH₄-concentrations has an added value to the (13)C/H₂ breath test to identify methanogenic subjects with lactose malabsorption or SIBO.

  19. High-Speed Electric Field Measurements and Lightning Mapping Observations at Langmuir Laboratory

    NASA Astrophysics Data System (ADS)

    Rison, W.; Edens, H. E.; Krehbiel, P. R.; Winn, W. P.; Aulich, G.; Hunyady, S. J.; Thomas, R. J.

    2007-12-01

    During the summer of 2007 we recorded broadband RF radiation waveforms, together with ground-based slow and fast electric field waveforms, from lightning in the vicinity of Langmuir Laboratory in central New Mexico. Three-dimensional observations of the lightning flashes from New Mexico Tech's Lightning Mapping Array (LMA) give context for interpreting the RF and electric field waveforms. In addition, high-speed in-situ vector electric field waveforms were recorded by a newly developed balloon-borne instrument. The broadband RF radiation was received using a Rhode & Schwarz model HE010 active rod antenna with a 100~MHz bandwidth, which was sampled at up to 400~MHz. Log-detected RF waveforms for two side-by-side LMA stations, one operating at 63 MHz (TV channel 3) and the other at 183 MHz (TV channel 9), and ground-based fast and slow electric field waveforms, were digitized at 25~MHz. All ground-based waveforms had a depth of 1~second, and were time-tagged with a GPS receiver. These comprehensive datasets are being used to study various processes associated with lightning flashes --- in particular, to detect high-frequency electrical activity at the onset of a flash. The ground based measurements, in conjunction with the in-situ vector field measurements, will be used to study the transfer of charge during a flash. Measurements of the log-detected RF (which is used by the LMA to map lightning flashes), in conjunction with the broadband RF and electric field waveforms, will help us better understand what types of events are detected and located by the LMA. In this paper we will present the results for a few interesting lightning flashes. ~

  20. Application of the Nordtest method for "real-time" uncertainty estimation of on-line field measurement.

    PubMed

    Näykki, Teemu; Virtanen, Atte; Kaukonen, Lari; Magnusson, Bertil; Väisänen, Tero; Leito, Ivo

    2015-10-01

    Field sensor measurements are becoming more common for environmental monitoring. Solutions for enhancing reliability, i.e. knowledge of the measurement uncertainty of field measurements, are urgently needed. Real-time estimations of measurement uncertainty for field measurement have not previously been published, and in this paper, a novel approach to the automated turbidity measuring system with an application for "real-time" uncertainty estimation is outlined based on the Nordtest handbook's measurement uncertainty estimation principles. The term real-time is written in quotation marks, since the calculation of the uncertainty is carried out using a set of past measurement results. There are two main requirements for the estimation of real-time measurement uncertainty of online field measurement described in this paper: (1) setting up an automated measuring system that can be (preferably remotely) controlled which measures the samples (water to be investigated as well as synthetic control samples) the way the user has programmed it and stores the results in a database, (2) setting up automated data processing (software) where the measurement uncertainty is calculated from the data produced by the automated measuring system. When control samples with a known value or concentration are measured regularly, any instrumental drift can be detected. An additional benefit is that small drift can be taken into account (in real-time) as a bias value in the measurement uncertainty calculation, and if the drift is high, the measurement results of the control samples can be used for real-time recalibration of the measuring device. The procedure described in this paper is not restricted to turbidity measurements, but it will enable measurement uncertainty estimation for any kind of automated measuring system that performs sequential measurements of routine samples and control samples/reference materials in a similar way as described in this paper.

  1. Magnetic-field sensing coil embedded in ceramic for measuring ambient magnetic field

    DOEpatents

    Takahashi, Hironori

    2004-02-10

    A magnetic pick-up coil for measuring magnetic field with high specific sensitivity, optionally with an electrostatic shield (24), having coupling elements (22) with high winding packing ratio, oriented in multiple directions, and embedded in ceramic material for structural support and electrical insulation. Elements of the coil are constructed from green ceramic sheets (200) and metallic ink deposited on surfaces and in via holes of the ceramic sheets. The ceramic sheets and the metallic ink are co-fired to create a monolithic hard ceramic body (20) with metallized traces embedded in, and placed on exterior surfaces of, the hard ceramic body. The compact and rugged coil can be used in a variety of environments, including hostile conditions involving ultra-high vacuum, high temperatures, nuclear and optical radiation, chemical reactions, and physically demanding surroundings, occurring either individually or in combinations.

  2. Helicon wave field measurements in Proto-MPEX

    NASA Astrophysics Data System (ADS)

    Caneses, Juan Francisco; Piotrowicz, Pawel; Goulding, Richard; Caughman, John; Showers, Missy; Kafle, Nischal; Rapp, Juergen; Campbell, Ian; Proto-MPEX Team

    2016-10-01

    A high density Deuterium discharge (ne 5e19 m-3, Te 4 eV) has been recently observed in ProtoMPEX (Prototype Material Plasma Exposure eXperiment). The discharge (100 kW, 13.56 MHz, D2, 700 G at the source, 1e4 G at the Target) begins with a low density plasma with hollow Te profile and transitions in about 100 ms to a high density mode with flat Te profile. It is believed that the transition to the high density mode is produced by a ``helicon resonance'' as evidenced by the centrally-peaked power deposition profile observed with IR imaging on a 2 mm thick metallic target plate. In this work, we present b-dot probe measurements of the radial helicon wavefields 30 cm downstream of the antenna during both the low and high density modes. In addition, we compare the experimental results with full wave simulations. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.

  3. A rapid automated procedure for laboratory and shipboard spectrophotometric measurements of seawater alkalinity: continuously monitored single-step acid additions

    NASA Astrophysics Data System (ADS)

    Liu, X.; Byrne, R. H.; Lindemuth, M.; Easley, R. A.; Patsavas, M. C.

    2012-12-01

    An automated system for shipboard and laboratory alkalinity measurements is presented. The simple system, which consists of a Dosimat titrator to deliver acid volumetrically and a USB 4000 spectrophotometer to monitor the titration progress, provides fast, precise and accurate measurements of total alkalinity for oceanographic research. The analytical method is based on single-point HCl titrations of seawater samples of a known volume; bromol cresol purple is used as an indicator to determine the final pH. Field data from an Arctic cruise demonstrates accuracy and precision around 1 micro mol/kg and a sample processing rate of 6 min per sample.

  4. Additional Reserve Recovery Using New Polymer Treatment on High Water Oil Ratio Wells in Alameda Field, Kingman County, Kansas

    SciTech Connect

    James Spillane

    2005-10-01

    The Chemical Flooding process, like a polymer treatment, as a tertiary (enhanced) oil recovery process can be a very good solution based on the condition of this field and its low cost compared to the drilling of new wells. It is an improved water flooding method in which high molecular-weight (macro-size molecules) and water-soluble polymers are added to the injection water to improve the mobility ratio by enhancing the viscosity of the water and by reducing permeability in invaded zones during the process. In other words, it can improve the sweep efficiency by reducing the water mobility. This polymer treatment can be performed on the same active oil producer well rather than on an injector well in the existence of strong water drive in the formation. Some parameters must be considered before any polymer job is performed such as: formation temperature, permeability, oil gravity and viscosity, location and formation thickness of the well, amount of remaining recoverable oil, fluid levels, well productivity, water oil ratio (WOR) and existence of water drive. This improved oil recovery technique has been used widely and has significant potential to extend reservoir life by increasing the oil production and decreasing the water cut. This new technology has the greatest potential in reservoirs that are moderately heterogeneous, contain moderately viscous oils, and have adverse water-oil mobility ratios. For example, many wells in Kansas's Arbuckle formation had similar treatments and we have seen very effective results. In addition, there were previous polymer treatments conducted by Texaco in Alameda Field on a number of wells throughout the Viola-Simpson formation in the early 70's. Most of the treatments proved to be very successful.

  5. Measurement of electric fields induced in a human subject due to natural movements in static magnetic fields or exposure to alternating magnetic field gradients

    NASA Astrophysics Data System (ADS)

    Glover, P. M.; Bowtell, R.

    2008-01-01

    A dual dipole electric field probe has been used to measure surface electric fields in vivo on a human subject over a frequency range of 0.1-800 Hz. The low-frequency electric fields were induced by natural body movements such as walking and turning in the fringe magnetic fields of a 3 T magnetic resonance whole-body scanner. The rate-of-change of magnetic field (dB/dt) was also recorded simultaneously by using three orthogonal search coils positioned near to the location of the electric field probe. Rates-of-change of magnetic field for natural body rotations were found to exceed 1 T s-1 near the end of the magnet bore. Typical electric fields measured on the upper abdomen, head and across the tongue for 1 T s-1 rate of change of magnetic field were 0.15 ± 0.02, 0.077 ± 0.003 and 0.015 ± 0.002 V m-1 respectively. Electric fields on the abdomen and chest were measured during an echo-planar sequence with the subject positioned within the scanner. With the scanner rate-of-change of gradient set to 10 T m-1 s-1 the measured rate-of-change of magnetic field was 2.2 ± 0.1 T s-1 and the peak electric field was 0.30 ± 0.01 V m-1 on the chest. The values of induced electric field can be related to dB/dt by a 'geometry factor' for a given subject and sensor position. Typical values of this factor for the abdomen or chest (for measured surface electric fields) lie in the range of 0.10-0.18 m. The measured values of electric field are consistent with currently available numerical modelling results for movement in static magnetic fields and exposure to switched magnetic field gradients.

  6. Measurement of electric fields induced in a human subject due to natural movements in static magnetic fields or exposure to alternating magnetic field gradients.

    PubMed

    Glover, P M; Bowtell, R

    2008-01-21

    A dual dipole electric field probe has been used to measure surface electric fields in vivo on a human subject over a frequency range of 0.1-800 Hz. The low-frequency electric fields were induced by natural body movements such as walking and turning in the fringe magnetic fields of a 3 T magnetic resonance whole-body scanner. The rate-of-change of magnetic field (dB/dt) was also recorded simultaneously by using three orthogonal search coils positioned near to the location of the electric field probe. Rates-of-change of magnetic field for natural body rotations were found to exceed 1 T s(-1) near the end of the magnet bore. Typical electric fields measured on the upper abdomen, head and across the tongue for 1 T s(-1) rate of change of magnetic field were 0.15+/-0.02, 0.077+/-0.003 and 0.015+/-0.002 V m(-1) respectively. Electric fields on the abdomen and chest were measured during an echo-planar sequence with the subject positioned within the scanner. With the scanner rate-of-change of gradient set to 10 T m(-1) s(-1) the measured rate-of-change of magnetic field was 2.2+/-0.1 T s(-1) and the peak electric field was 0.30+/-0.01 V m(-1) on the chest. The values of induced electric field can be related to dB/dt by a 'geometry factor' for a given subject and sensor position. Typical values of this factor for the abdomen or chest (for measured surface electric fields) lie in the range of 0.10-0.18 m. The measured values of electric field are consistent with currently available numerical modelling results for movement in static magnetic fields and exposure to switched magnetic field gradients.

  7. Real-time interferometric monitoring and measuring of photopolymerization based stereolithographic additive manufacturing process: sensor model and algorithm

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Rosen, D. W.

    2017-01-01

    As additive manufacturing is poised for growth and innovations, it faces barriers of lack of in-process metrology and control to advance into wider industry applications. The exposure controlled projection lithography (ECPL) is a layerless mask-projection stereolithographic additive manufacturing process, in which parts are fabricated from photopolymers on a stationary transparent substrate. To improve the process accuracy with closed-loop control for ECPL, this paper develops an interferometric curing monitoring and measuring (ICM&M) method which addresses the sensor modeling and algorithms issues. A physical sensor model for ICM&M is derived based on interference optics utilizing the concept of instantaneous frequency. The associated calibration procedure is outlined for ICM&M measurement accuracy. To solve the sensor model, particularly in real time, an online evolutionary parameter estimation algorithm is developed adopting moving horizon exponentially weighted Fourier curve fitting and numerical integration. As a preliminary validation, simulated real-time measurement by offline analysis of a video of interferograms acquired in the ECPL process is presented. The agreement between the cured height estimated by ICM&M and that measured by microscope indicates that the measurement principle is promising as real-time metrology for global measurement and control of the ECPL process.

  8. A comparison of satellite systems for gravity field measurements

    NASA Technical Reports Server (NTRS)

    Argentiero, P. D.; Lowrey, B. E.

    1977-01-01

    A detailed and accurate earth gravity field model is important to the understanding of the structure and composition of the earth's crust and upper mantle. Various satellite-based techniques for providing more accurate models of the gravity field are analyzed and compared. A high-low configuration satellite-to-satellite tracking mission is recommended for the determination of both the long wavelength and short wavelength portions of the field. Satellite altimetry and satellite gradiometry missions are recommended for determination of the short wavelength portion of the field.

  9. Field measurements of tracer gas transport by barometric pumping

    SciTech Connect

    Lagus, P.L.; McKinnis, W.B.; Hearst, J.R.; Burkhard, N.R.; Smith, C.F.

    1994-07-28

    Vertical gas motions induced by barometric pressure variations can carry radioactive gases out of the rubblized region produced by an underground nuclear explosion, through overburden rock, into the atmosphere. To better quantify transit time and amount of transport, field experiments were conducted at two sites on Pahute Mesa, Kapelli and Tierra, where radioactive gases had been earlier detected in surface cracks. At each site, two tracer gases were injected into the rubblized chimney 300-400 m beneath the surface and their arrival was monitored by concentration measurements in gas samples extracted from shallow collection holes. The first ``active`` tracer was driven by a large quantity of injected air; the second ``passive`` tracer was introduced with minimal gas drive to observe the natural transport by barometric pumping. Kapelli was injected in the fall of 1990, followed by Tierra in the fall of 1991. Data was collected at both sites through the summer of 1993. At both sites, no surface arrival of tracer was observed during the active phase of the experiment despite the injection of several million cubic feet of air, suggesting that cavity pressurization is likely to induce horizontal transport along high permeability layers rather than vertical transport to the surface. In contrast, the vertical pressure gradients associated with barometric pumping brought both tracers to the surface in comparable concentrations within three months at Kapelli, whereas 15 months elapsed before surface arrival at Tierra. At Kapelli, a quasisteady pumping regime was established, with tracer concentrations in effluent gases 1000 times smaller than concentrations thought to exist in the chimney. Tracer concentrations observed at Tierra were typically an order of magnitude smaller. Comparisons with theoretical calculations suggest that the gases are traveling through {approximately}1 millimeter vertical fractures spaced 2 to 4 meters apart. 6 refs., 18 figs., 3 tabs.

  10. Wide field array calibration dependence on the stability of measured dose distributions

    SciTech Connect

    Simon, Thomas A.; Simon, William E.; Kahler, Darren; Li, Jonathan; Liu, Chihray

    2010-07-15

    Purpose: The aim of this work was to simulate the effect of dose distribution changes on detector array calibrations and to explore compensatory methods that are used during calibration measurements. Methods: The array calibration technique that was investigated is known as wide field (WF) calibration. Using this method, a linear array [y-axis (65 detectors) of the IC PROFILER (Sun Nuclear Corporation, Melbourne, FL)] is calibrated with three measurements ({alpha}, {theta}, and {lambda}); each measurement uses the same radiation field, which is larger than the array. For measurement configuration {theta}, the array is rotated by 180 deg. from its position in {alpha}; for {lambda}, the array is shifted by one detector from its position in {theta}. The relative detector sensitivities are then determined through ratios of detector readings at the same field locations (using {theta} and {lambda}). This method results in error propagation that is proportional to the number of detectors in the array. During the procedure, the calibration protocol operates under three postulates, which state that (a) the beam shape does not change between measurements; (b) the relative sensitivities of the detectors do not change; and (c) the scatter to the array does not change as the array is moved. The WF calibration's sensitivity to a postulate (a) violation was quantified by applying a sine shaped perturbation (of up to 0.1%) to {alpha}, {theta}, or {lambda}, and then determining the change relative to a baseline calibration. Postulate (a) violations were minimized by using a continuous beam and mechanized array movement during {theta} and {lambda}. A continuously on beam demonstrated more stable beam symmetry as compared to cycling the beam on and off between measurements. Additional side-scatter was also used to satisfy postulate (c). Results: Simulated symmetry perturbations of 0.1% to {theta} or {lambda} resulted in calibration errors of up to 2%; {alpha} was relatively immune to

  11. Stereoscopic PIV measurements of the flow field in a turbine cascade

    NASA Astrophysics Data System (ADS)

    Tian, Yangtao; Ma, Hongwei; Ma, Rong

    2017-02-01

    This paper presents experimental measurements of the flow field in a Low-speed Turbine Cascade using a stereoscopic particle-image velocimetry (SPIV). During the measurements, a pair of frame-straddling-based CCD cameras were configured at different sides of the laser light sheet, and appropriate tracing particles (DEHS) were employed. The measurements were conducted at the incidence angle of 0 degree and exit Reynolds number of 1.7 × 105 with the tip clearance 1.18% of blade chord. The tip flow features, such as the evolution and breakdown of tip leakage vortex, the horseshoe vortex, turbulence characteristics of tip leakage flow, were studied for the flow field analysis. The results showed that the tip leakage flow/vortex mainly dominate flow fields in the tip region. The tip leakage vortex performs as a concentrated vortex before its breaking down and splitting into small vortices. The highest turbulence intensity mainly occurs in the tip region along with the trajectory of tip leakage vortex, and when the vortex breaks down, the turbulence intensity reduces rapidly. Additionally, the SPIV with this configuration also shows an advantage in investigating the flow structures and mechanism inside the turbine cascade.

  12. Electric-field-vector measurement in a glow discharge

    SciTech Connect

    Ganguly, B.N.; Garscadden, A.

    1985-10-01

    The magnetic quantum number selection rule implies that radiation that is linearly polarized perpendicular to the electric field will not excite ..delta..m = 0 transitions. This phenomenon in Stark spectra has been used to determine the electric field vector in a positive column dc discharge in helium. The technique is applicable to both linear and nonlinear Stark effects.

  13. Magnetic field measurements based on Terfenol coated photonic crystal fibers.

    PubMed

    Quintero, Sully M M; Martelli, Cicero; Braga, Arthur M B; Valente, Luiz C G; Kato, Carla C

    2011-01-01

    A magnetic field sensor based on the integration of a high birefringence photonic crystal fiber and a composite material made of Terfenol particles and an epoxy resin is proposed. An in-fiber modal interferometer is assembled by evenly exciting both eigenemodes of the HiBi fiber. Changes in the cavity length as well as the effective refractive index are induced by exposing the sensor head to magnetic fields. The magnetic field sensor has a sensitivity of 0.006 (nm/mT) over a range from 0 to 300 mT with a resolution about ±1 mT. A fiber Bragg grating magnetic field sensor is also fabricated and employed to characterize the response of Terfenol composite to the magnetic field.

  14. Measurement of water by oven evaporation using a novel oven design. 2. Water in motor oils and motor oil additives.

    PubMed

    Margolis, Sam A; Vaishnav, Kevin; Sieber, John R

    2004-11-01

    The measurement of water in lubricating oils is important because water accelerates the corrosion of metal parts and bearings in motors. Some of the additives added to lubricating oils to improve their performance react with the Karl Fischer reagent (KFR) causing a positive bias in the water measurement. A new oven evaporation technique for measuring water in oils has been developed that is automated, requires less sample handling, is easily calibrated, and is capable of measuring relatively small mass fractions of water (> or =50 mg/kg sample). A series of motor oils was analyzed with the standard KFR, a reagent that detects interfering substances that reduce iodine, and the aldehyde-ketone reagent that does not detect substances that react with methanol and form water. The oil samples were heated to 107 degrees C and then reheated to 160 degrees C. At both temperatures, material was measured by both KFRs, but only zinc dithiophosphate released sulfur compounds that would react with the reagent that detects interfering substances. Mass fractions of between 20 and 70% of the volatile material released at either temperature were measured with the standard KFR but not with the aldehyde-ketone reagent. These results demonstrate that there are a number of sources of positive bias in the measurement of water in motor oils and that the standard KFR cannot be used to measure water in motor oils and motor oil additives. These results also indicate that some of the material reacts with methanol to form water. Finally, these results suggest that some of the material that is volatile at 160 degrees C and not at 107 degrees C may be water that is physically occluded or may be substances that react with diethyleneglycol monomethylether to produce water.

  15. Toward the Direct Measurement of Coronal Magnetic Fields: An Airborne Infrared Spectrometer for Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Samra, J.; DeLuca, E. E.; Golub, L.; Cheimets, P.

    2014-12-01

    The solar magnetic field enables the heating of the corona and provides its underlying structure. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections (CME) and provides the ultimate source of energy for space weather. Therefore, direct measurements of the coronal magnetic field have significant potential to enhance understanding of coronal dynamics and improve solar forecasting models. Of particular interest are observations of coronal field lines in the transitional region between closed and open flux systems, providing important information on the origin of the slow solar wind. While current instruments routinely observe only the photospheric and chromospheric magnetic fields, a proposed airborne spectrometer will take a step toward the direct observation of coronal fields by measuring plasma emission in the infrared at high spatial and spectral resolution. The targeted lines are four forbidden magnetic dipole transitions between 2 and 4 μm. The airborne system will consist of a telescope, grating spectrometer, and pointing/stabilization system to be flown on the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) during the August 2017 total solar eclipse. The project incorporates several optical engineering challenges, centered around maintaining adequate spectral and spatial resolution in a compact and inexpensive package and on a moving platform. Design studies are currently underway to examine the tradeoffs between various optical geometries and control strategies for the pointing/stabilization system. The results will be presented and interpreted in terms of the consequences for the scientific questions. In addition, results from a laboratory prototype and simulations of the final system will be presented.

  16. Dermal exposure of pesticide applicators as a measure of coverall performance under field conditions.

    PubMed

    Machera, K; Tsakirakis, A; Charistou, A; Anastasiadou, P; Glass, C R

    2009-08-01

    In this study, the field performance of two coverall designs used by pesticide applicators was determined. Two coverall types were selected based on data from previously conducted comfort testing under field conditions in southern Europe. Dermal exposure was measured during 22 applications conducted with 11 operators using similar hand-held spray guns in greenhouse pepper crops in the Ierapetra region of Crete, Greece. One of the coverall designs studied was made from a cotton/polyester material treated with a water-repellent Resist Spills(R) finish, which was compared in the field study to a coverall of similar design, but using a woven, untreated cotton material. An in-house analytical method was developed and validated for determining residues of the active substance (a.s.) malathion on the dosimeters. The derived levels of dermal exposure were used as a measure of the protection provided by the two types of coveralls. In addition, by comparing the total amount of the a.s. recovered from outer and inner dosimeters (potential dermal exposure = 238.8 mg kg(-1) a.s. for the cotton coverall and 160.44 mg kg(-1) a.s. for the Resist Spills coverall), a value could be determined for the degree of coverall penetration. The mean penetration (milligrams per kilogram a.s.) of the outer coveralls, calculated as a percentage of the total contamination, was 0.4% for the water-repellent coverall and 2.3% for the cotton coverall. The mean recovery from the laboratory and field-fortified samples was >91 and 74%, respectively and used as the main criterion for quality control of the analytical data. Under the field trial conditions evaluated, both the coverall designs gave better protection than the default values used in the most relevant predictive exposure model. Therefore, they could be considered as appropriate tools of personal protection when both comfort and field performance is taken into account under the specific application scenario.

  17. New measurements of sextupole field decay and snapback effect on Tevatron dipole magnets

    SciTech Connect

    Velev, G.V.; Bauer, P.; Carcagno, R.; DiMarco, J.; Lamm, M.; Orris, D.; Schlabach, P.; Sylvester, C.; Tartaglia, M.; Tompkins, J.; /Fermilab

    2006-07-01

    To perform detailed studies of the dynamic effects in superconducting accelerator magnets, a fast continuous harmonics measurement system based on the application of a digital signal processor (DSP) has been built at Fermilab. Using this new system, the dynamic effects in the sextupole field, such as the field decay during the dwell at injection and the rapid subsequent ''snapback'' during the first few seconds of the energy ramp, are evaluated for more than ten Tevatron dipoles from the spare pool. The results confirm the previously observed fast drift in the first several seconds of the sextupole decay and provide additional information on a scaling law for predicting snapback duration. The information presented here can be used for an optimization of the Tevatron and for future LHC operations.

  18. Measurements of N2O emissions from different vegetable fields on the North China Plain

    NASA Astrophysics Data System (ADS)

    Diao, Tiantian; Xie, Liyong; Guo, Liping; Yan, Hongliang; Lin, Miao; Zhang, He; Lin, Jia; Lin, Erda

    2013-06-01

    Few studies have measured the N2O emission fluxes from vegetable fields. In order to identify the characteristics and the influencing factors of N2O emissions from different vegetable fields, we measured N2O emissions for a full year from four typical fields, including an open-ground vegetable field that has produced vegetables for over 20 years (OV20), a recently developed open-ground vegetable field that was converted from a maize field three years earlier (OV3), a recently developed greenhouse vegetable field that was converted from a maize field 3 years earlier (GV3) and a typical local maize field (Maize). Four different fertilization treatments were set additionally in the recently developed open-ground vegetable field. These were: no fertilizer or manure (OV3_CK), manure only (OV3_M) and the combination of manure with different rates of chemical fertilizer application (OV3_MF1 and OV3_MF3). The results showed that N2O emission fluxes fluctuated between 0.3 ± 0.1 and 912.4 ± 80.0 mg N2O-N m-2 h-1 with the highest emission peak occurring after fertilization followed by irrigation. Nitrogen application explained 64.6-84.5% of the N2O emission in the vegetable fields. The magnitude of the emission peaks depended on the nitrogen application rate and the duration of the emission peaks was mainly associated with soil temperature when appropriate irrigation was given after fertilization. The N2O emission peaks occurred later and lasted for a longer period when the soil temperature was <24 °C in May. However, emission peaks occurred earlier and lasted for a shorter period when the soil temperature was around 25-33 °C from June to August. The annual N2O emissions from the fertilized vegetable fields were 1.68-2.38 times higher than that from the maize field, which had an emission value of 2.88 ± 0.10 kg N ha-1 a-1. The N2O emission factor (EF) of manure nitrogen was 0.07% over the whole year, but was 0.11% and 0.02% in the spring cucumber season and the autumn

  19. Enabling Continuous, Field-Based Isotope and Greenhouse Gas Measurements with WS-CRDS-based Analyzers

    NASA Astrophysics Data System (ADS)

    Rella, C.; van Pelt, A.

    2009-04-01

    When new instrumentation becomes widely available, it has the power to fundamentally change how measurements are made. In particular, technology developments that enable measurements to be done more simply, at lower cost, by a greater number of scientists, moving information-rich, laboratory-quality measurements from the lab out into the field -- these are the innovations that can aid in moving the science forward. Here we describe how the application of a novel cavity-enhanced spectroscopic technique called wavelength scanned cavity ring down spectroscopy (WS-CRDS) has been pivotal in developing gas an isotope analyzers capable of being deployed in the field, unattended, for long periods of time. This particular implementation of the traditional cavity ring down technique employs several additional key aspects of control and design to achieve highly sensitive, highly stable measurements. WS-CRDS owes its high sensitivity to an extremely long optical interaction pathlengh, as well as to its complete immunity to laser noise since the laser is actually off during the measurement. To stabilize the spectroscopic line itself, the temperature and pressure of the gas are tightly controlled. The analyzer's optical cavity, gas handling system and analog electronics are themselves also tightly temperature controlled. The heart of the WS-CRDS technique is, however, the wavelength monitor which further ensures the stability of the measurement by continuously measuring and tightly controlling the laser wavelength. A key design aspect of the WS-CRDS analyzer is its three-mirror, traveling-wave cavity which allows optical backreflections to be avoided and further adds to the inherent stability of the optical train. The analyzer owes its ease of use to the design requirement that it be field-deployable, in locations without personnel, with the ability to restart itself and automatically resume collecting data even after a power failure. Beyond the design aspects of the analyzer

  20. Third Wave of Measurement in the Self-Regulated Learning Field: When Measurement and Intervention Come Hand in Hand

    ERIC Educational Resources Information Center

    Panadero, Ernesto; Klug, Julia; Järvelä, Sanna

    2016-01-01

    Measurement is a central issue for the self-regulated learning (SRL) field as SRL is a phenomenon difficult to measure in a reliable and valid way. Here, 3 waves in the history of SRL measurement are identified and profiled. Our focus lies on the third and newest one, which combines measurement and intervention within the same tools. The basis for…

  1. 47 CFR 73.314 - Field strength measurements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... transmitting antenna. (B) Ground elevation at measuring location. (C) Date, time of day, and weather. (D... measurements were made, drawn on curved earth paper for equivalent 4/3 earth radius, of the largest...

  2. Comparison and Evaluation of Laboratory and Field Measured Bioaccumulation Endpoints

    EPA Science Inventory

    Evaluation of bioaccumulation endpoints on a fugacity basis allows provides a framework to assess the biomagnification potential of a chemical and assess data deficiencies, i.e., uncertainties and lack of data. In addition, it is suggested that additional guidance is needed in o...

  3. Control of hydrogen sulfide production in oil fields by managing microbial communities through nitrate or nitrite addition

    NASA Astrophysics Data System (ADS)

    Hubert, Casey R. J.

    Nitrate or nitrite injection into oil reservoirs during water flooding has the potential to control biological souring, the production of hydrogen sulfide (H2S) by sulfate-reducing bacteria (SRB). Souring control is essential because sulfide is toxic, sulfide precipitates can plug reservoir formations, souring lowers crude oil value, and SRB induce corrosion. Nitrate and nitrite can stimulate heterotrophic nitrate- or nitrite-reducing bacteria (hNRB) and nitrate- or nitrite-reducing, sulfide oxidizing bacteria (NRSOB). Nitrite also inhibits SRB activity by blocking the sulfate reduction pathway. Continuous up-flow packed-bed bioreactors were inoculated with produced water from the Coleville oil field to establish sulfide-producing biofilms similar to those found in sour reservoirs. Nitrate or nitrite addition to bioreactors indicated that the dose required for hNRB or NR-SOB to control souring depended on the concentration of oil organics. Either mechanism mediates the net removal of oil organics (lactate) with nitrate or nitrite, with lower doses of nitrate required due to its greater oxidative power. Microbial community analysis by reverse sample genome probing (RSGP) revealed that NR-SOB mediated sulfide removal at low nitrate or nitrite concentrations when lactate was still available to SRB and the redox potential was low. At high nitrate doses hNRB oxidized lactate directly, produced nitrite and maintained a high redox potential, thus excluding SRB activity. Facultatively chemolithotrophic Campylobacter sp. strains were isolated from the bioreactors and incorporated into RSGP analyses, revealing their dominance in both NR-SOB- and hNRB-containing communities. The metabolic flexibility of these strains may confer a competitive advantage over obligate chemolithotrophs like Thiomicrospira sp. strain CVO or hNRB that do not have NR-SOB activity like newly isolated Thauera sp. and Rhodobacter sp. strains. A single high dose of nitrite resulted in immediate

  4. Chlorophyll fluorescence and the polarized underwater light field: comparison of vector radiative transfer simulations and multi-angular hyperspectral polarization field measurements

    NASA Astrophysics Data System (ADS)

    El-habashi, Ahmed; Ahmed, Samir

    2016-05-01

    Previous partial simulations and field measurements by us, had demonstrated the impact of the un-polarized nature of algal chlorophyll fluorescence to reduce the observed degree of polarization of the underwater light field in the spectral vicinity of fluorescence. (Polarization otherwise existing as a result of non-algal particulate (NAP) and molecular elastic scattering). The magnitude of this fluorescence driven dip in the observed degree of polarization was also seen to be theoretically related to the fluorescence magnitude. The recent availability to us of the RayXP vector radiative transfer code (VRTE) for the coupled atmosphere ocean system now permits us to make complete simulations of the underwater polarized light field, using measured inherent optical properties (IOPs) as inputs. Based on these simulations, a much more comprehensive analysis of the fluorescence impact is now possible. Combining the results of these new simulations with underwater field measurements in eutrophic waters using our hyperspectral multi angle polarimeter, we verified the theoretical relationship. In addition, comparisons of VRTE simulations and hyperspectral polarized field measurements for various coastal water conditions permit retrieval of fluorescence magnitudes. Comparisons of these polarization based fluorescence retrievals with retrievals obtained using fluorescence height over baseline or Hydrolight scalar simulations, together with total unpolarized radiance measurements, show good agreement.

  5. 47 CFR 73.686 - Field strength measurements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Multiple signals. If more than one signal is being measured (i.e., signals from different transmitters... the measurement. (iii) Multiple signals— (A) If more than one signal is being measured (i.e., signals... eligibility of a satellite subscriber to receive distant network signals, only stations affiliated with...

  6. A fast response miniature probe for wet steam flow field measurements

    NASA Astrophysics Data System (ADS)

    Bosdas, Ilias; Mansour, Michel; Kalfas, Anestis I.; Abhari, Reza S.

    2016-12-01

    Modern steam turbines require operational flexibility due to renewable energies’ increasing share of the electrical grid. Additionally, the continuous increase in energy demand necessitates efficient design of the steam turbines as well as power output augmentation. The long turbine rotor blades at the machines’ last stages are prone to mechanical vibrations and as a consequence time-resolved experimental data under wet steam conditions are essential for the development of large-scale low-pressure steam turbines. This paper presents a novel fast response miniature heated probe for unsteady wet steam flow field measurements. The probe has a tip diameter of 2.5 mm, and a miniature heater cartridge ensures uncontaminated pressure taps from condensed water. The probe is capable of providing the unsteady flow angles, total and static pressure as well as the flow Mach number. The operating principle and calibration procedure are described in the current work and a detailed uncertainty analysis demonstrates the capability of the new probe to perform accurate flow field measurements under wet steam conditions. In order to exclude any data possibly corrupted by droplets’ impact or evaporation from the heating process, a filtering algorithm was developed and implemented in the post-processing phase of the measured data. In the last part of this paper the probe is used in an experimental steam turbine test facility and measurements are conducted at the inlet and exit of the last stage with an average wetness mass fraction of 8.0%.

  7. A method of analyzing nonstationary ionic channel current fluctuations in the presence of an additive measurement noise.

    PubMed

    Mino, H

    1993-03-01

    A method of estimating the parameters of nonstationary ionic channel current fluctuations (NST-ICF's) in the presence of an additive measurement noise is proposed. The case is considered in which the sample records of NST-ICT's corrupted by the measurement noise are available for estimation, where the experiment can be repeated many times to calculate the statistics of noisy NST-ICF's. The conventional second-order regression model expressed in terms of the mean and variance of noisy NST-ICF's is derived theoretically, assuming that NST-ICF's are binomially distributed. Since the coefficients of the regression model are explicitly related to not only the parameters of NST-ICF's but also the measurement noise component, the parameters of NST-ICF's that are of interest can be estimated without interference from the additive measurement noise by identifying the regression coefficients. Furthermore, the accuracy of the parameter estimates is theoretically evaluated using the error-covariance matrix of the regression coefficients. The validity and effectiveness of the proposed method are demonstrated in a Monte Carlo simulation in which a fundamental kinetic scheme of Na+ channels is treated as a specific example.

  8. Field-scale investigation of enhanced petroleum hydrocarbon biodegradation in the vadose zone combining soil venting as an oxygen source with moisture and nutrient addition. Appendices. Doctoral thesis

    SciTech Connect

    Miller, R.N.

    1990-01-01

    This document contains appendices regarding a reprint on a field scale investigation of enhanced petroleum hydrocarbon biodegradation in the vadose zone combining soil venting as a oxygen source with moisture and nutrient addition.

  9. A supernova scenario for magnetic fields and rotation measures in galaxies

    NASA Astrophysics Data System (ADS)

    Beck, Alexander; Dolag, Klaus; Lesch, Harald

    2015-08-01

    We present a model for the seeding and evolution of magnetic fields in protogalaxies. Supernova SN explosions during the assembly of a protogalaxy provide magnetic seed fields, which are subsequently amplified by compression, shear flows and random motions. Our model explains the origin of strong magnetic fields of microG amplitude within the first starforming protogalactic structures shortly after onset of star formation. We implement the model into the MHD version of the cosmological N-body / SPH simulation code GADGET and we couple the magnetic seeding directly to the underlying multi-phase description of star formation. We perform simulations of Milky Way-like galactic halo formation using a standard LCDM cosmology and analyse the strength and distribution of the subsequent evolving magnetic field.Within starforming regions and given typical dimensions and magnetic field strengths in canonical SN remnants, we inject a dipole-shape magnetic field at a rate of nG/Gyr.Subsequently, the magnetic field strength increases exponentially on timescales of a few ten million years within the innermost regions of the halo. Furthermore, turbulent diffusion, shocks and gas motions transport the magnetic field towards the halo outskirts. At redshift z=0, the entire galactic halo is magnetized and the field amplitude is of the order of a few microG in the center of the halo and nG at the virial radius. Additionally, we analyse the intrinsic rotation measure (RM) of the forming galactic halo over redshift. The mean halo intrinsic RM peaks between redshifts z=4 and z=2 and reaches absolute values around 1000 rad/m^2.While the halo virializes towards redshift z=0, the intrinsic RM values decline to a mean value below 10 rad/m^2. At high redshifts, the distribution of individual starforming and thus magnetized regions is widespread. This leads to a widespread distribution of large intrinsic RM values. In our model, galactic magnetic fields are a consequence of the star formation

  10. Analysis of the laser powder bed fusion additive manufacturing process through experimental measurement and finite element modeling

    NASA Astrophysics Data System (ADS)

    Dunbar, Alexander Jay

    The objective in this work is to provide rigourous experimental measurements to aid in the development of laser powder bed fusion (LPBF) additive manufacturing (AM). A specialized enclosed instrumented measurement system is designed to provide in situ experimental measurements of temperature and distortion. Experiments include comparisons of process parameters, materials and LPBF machines. In situ measurements of distortion and temperature made throughout the build process highlight inter-layer distortion effects previously undocumented for laser powder bed fusion. Results from these experiments are also be implemented in the development and validation of finite element models of the powder bed build process. Experimental analysis is extended from small-scale to larger part-scale builds where experimental post-build measurements are used in analysis of distortion profiles. Experimental results provided from this study are utilized in the validation of a finite element model capable of simulating production scale parts. The validated finite element model is then implemented in the analysis of the part to provide information regarding the distortion evolution process. A combination of experimental measurements and simulation results are used to identify the mechanism that results in the measured distortion profile for this geometry. Optimization of support structure primarily focuses on the minimization of material use and scan time, but no information regarding failure criteria for support structure is available. Tensile test samples of LPBF built support structure are designed, built, and tested to provide measurements of mechanical properties of the support structure. Experimental tests show that LPBF built support structure has only 30-40% of the ultimate tensile strength of solid material built in the same machine. Experimental measurement of LPBF built support structure provides clear failure criteria to be utilized in the future design and implementation of

  11. Measuring bi-directional current through a field-effect transistor by virtue of drain-to-source voltage measurement

    DOEpatents

    Turner, Steven Richard

    2006-12-26

    A method and apparatus for measuring current, and particularly bi-directional current, in a field-effect transistor (FET) using drain-to-source voltage measurements. The drain-to-source voltage of the FET is measured and amplified. This signal is then compensated for variations in the temperature of the FET, which affects the impedance of the FET when it is switched on. The output is a signal representative of the direction of the flow of current through the field-effect transistor and the level of the current through the field-effect transistor. Preferably, the measurement only occurs when the FET is switched on.

  12. 47 CFR 73.153 - Field strength measurements in support of applications or evidence at hearings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Field strength measurements in support of... (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES AM Broadcast Stations § 73.153 Field strength..., groundwave field strength measurements will take precedence over theoretical values, provided...

  13. Solar magnetic fields measurements with a magneto-optical filter

    NASA Technical Reports Server (NTRS)

    Cacciani, A.; Ricci, D.; Rosati, P.; Rhodes, E. J.; Smith, E.

    1990-01-01

    The presence of a magnetic field at different levels inside the sun has crucial implications for helioseismology. The solar oscillation observing program carried out since 1983 at Mt. Wilson with Cacciani magneto-optical filter has recently been modified to acquire full-disk magnetograms with 2 arcsec spatial resolution. A method for the correct determination of magnetic maps which are free of contamination by velocity signal is presented. It is shown that no cross-talk exists between the Doppler and Zeeman shifts of the Na D lines, provided that instrumental polarization effects are taken into account. The observed line-of-sight photospheric field was used to map the vector field in the inner corona, above active regions, in the current free approximation.

  14. Electromagnetic Near Field Measurements of Two Critical Assemblies

    SciTech Connect

    Goettee, Jeffrey David

    2015-11-03

    The reactors employed, Godiva IV and WSMR Fast Burst Reactor, are described first. Then the point reactor kinetics model, electromagnetic potential, and the measurement of kinetics quantities are successively discussed. In summary, reactor power produces measurable electric energy. The electric signal mimics power curve for prompt burst operations - features in logarithmic derivatives match. The electric signature should be dependent on the power and not the derivative; therefore, steady-state modes should be measurable.

  15. An Undergraduate Field Experiment for Measuring Exposure to Environmental Tobacco Smoke in Indoor Environments

    NASA Astrophysics Data System (ADS)

    Marsella, Adam M.; Huang, Jiping; Ellis, David A.; Mabury, Scott A.

    1999-12-01

    An undergraduate field experiment is described for the measurement of nicotine and various carbonyl compounds arising from environmental tobacco smoke. Students are introduced to practical techniques in HPLC-UV and GC-NPD. Also introduced are current methods in personal air sampling using small and portable field sampling pumps. Carbonyls (formaldehyde, acetaldehyde, acrolein, and acetone) are sampled with silica solid-phase extraction cartridges impregnated with 2,4-dinitrophenylhydrazine, eluted, and analyzed by HPLC-UV (360-380 nm). Nicotine is sampled using XAD-2 cartridges, extracted, and analyzed by GC-NPD. Students gain an appreciation for the problems associated with measuring ubiquitous pollutants such as formaldehyde, as well as the issue of chromatographic peak resolution when trying to resolve closely eluting peaks. By allowing the students to formulate their own hypothesis and sampling scheme, critical thinking and problem solving are developed in addition to analysis skills. As an experiment in analytical environmental chemistry, this laboratory introduces the application of field sampling and analysis techniques to the undergraduate lab.

  16. Velocity and magnetic field measurements of Taylor plumes in SSX under different boundary conditions

    NASA Astrophysics Data System (ADS)

    Kaur, Manjit; Brown, M. R.; Han, J.; Shrock, J. E.; Schaffner, D. A.

    2016-10-01

    The SSX device has been modified by the addition of a 1 m long glass extension for accommodating pulsed theta pinch coils. The Taylor plumes are launched from a magnetized plasma gun and flow to an expansion volume downstream. The time of flight (TOF) measurements of these plumes are carried out using a linear array of Ḃ probes (separated by 10cm). TOF of the plasma plumes from one probe location to the next is determined by direct comparison of the magnetic field structures as well as by carrying out a cross-correlation analysis. With the glass boundary, the typical velocity of the Taylor plumes is found to be 25km /s , accompanied by a fast plasma (>= 50km /s) at the leading edge. Magnetic field embedded in the Taylor plumes is measured in the expansion chamber using a three-dimensional array of Ḃ probes and is found to be 700G . Some flux conservation of the Taylor plumes is provided by using a resistive (soak time 3 μs) and a mesh (soak time 170 μs > discharge time) liner around the glass tube for improving the downstream Taylor state velocity as well as the magnetic field. The results from these different boundary conditions will be presented. Work supported by DOE OFES and ARPA-E ALPHA programs.

  17. Strong Nonuniform Magnetic Field for Self-Diffusion Measurement by NMR in the Earth's Magnetic-Field

    NASA Astrophysics Data System (ADS)

    Stepisnik, J.; Kos, M.; Planinsic, G.; Erzen, V.

    Self-diffusion measurement by NMR requires a magnetic-field gradient that is strong enough to cause sufficient dephasing of the signal of migrating spins in the time of its application. The spin-relaxation mechanism limits the duration of the gradient field, and whenever particle migration is slow, the strength of the required inhomogeneous magnetic field may exceed that of the main magnetic field. In this case, the definition of the magnetic-field gradient fails and the usual formula for self-diffusion attenuation of spin echoes is no longer valid. This always happens with NMR in the earth's weak magnetic field. In the paper an expression for the self-diffusion attenuation of the spin echo is derived that is valid for a strong nonuniform magnetic field, and it is shown that the nonuniform magnetic field must have the appropriate spatial symmetry and that only isotropic self-diffusion can be measured with the new method. NMR measurement in the earth's magnetic field of the self-diffusion constants in some liquids confirms these results.

  18. Electric field measuring and display system. [for cloud formations

    NASA Technical Reports Server (NTRS)

    Wojtasinski, R. J.; Lovall, D. D. (Inventor)

    1974-01-01

    An apparatus is described for monitoring the electric fields of cloud formations within a particular area. It utilizes capacitor plates that are alternately shielded from the clouds for generating an alternating signal corresponding to the intensity of the electric field of the clouds. A synchronizing signal is produced for controlling sampling of the alternating signal. Such samplings are fed through a filter and converted by an analogue to digital converter into digital form and subsequently fed to a transmitter for transmission to the control station for recording.

  19. Hazard surveillance for workplace magnetic fields. 1: Walkaround sampling method for measuring ambient field magnitude; 2: Field characteristics from waveform measurements

    SciTech Connect

    Methner, M.M.; Bowman, J.D.

    1998-03-01

    Recent epidemiologic research has suggested that exposure to extremely low frequency (ELF) magnetic fields (MF) may be associated with leukemia, brain cancer, spontaneous abortions, and Alzheimer`s disease. A walkaround sampling method for measuring ambient ELF-MF levels was developed for use in conducting occupational hazard surveillance. This survey was designed to determine the range of MF levels at different industrial facilities so they could be categorized by MF levels and identified for possible subsequent personal exposure assessments. Industries were selected based on their annual electric power consumption in accordance with the hypothesis that large power consumers would have higher ambient MFs when compared with lower power consumers. Sixty-two facilities within thirteen 2-digit Standard Industrial Classifications (SIC) were selected based on their willingness to participate. A traditional industrial hygiene walkaround survey was conducted to identify MF sources, with a special emphasis on work stations.

  20. AUV Turbulence Measurements in the LOCO Field Experiments

    DTIC Science & Technology

    2008-01-01

    measure pitch , roll , yaw, and other internal dynamical parameters. This suite of sensors on T-REMUS allows quantification of the key dynamical and...Inc., containing the Rockland Microstructure Measurement System (RMMS), an upward and downward looking 1.2 MHz ADCP , a FASTCAT Seabird CTD, and a WET