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Sample records for ac loss measurements

  1. AC Loss Measurements on a 2G YBCO Coil

    SciTech Connect

    Rey, Christopher M; Duckworth, Robert C; Schwenterly, S W

    2011-01-01

    The Oak Ridge National Laboratory (ORNL) is collaborating with Waukesha Electric Systems (WES) to continue development of HTS power transformers. For compatibility with the existing power grid, a commercially viable HTS transformer will have to operate at high voltages in the range of 138 kV and above, and will have to withstand 550-kV impulse voltages as well. Second-generation (2G) YBCO coated conductors will be required for an economically-competitive design. In order to adequately size the refrigeration system for these transformers, the ac loss of these HTS coils must be characterized. Electrical AC loss measurements were conducted on a prototype high voltage (HV) coil with co-wound stainless steel at 60 Hz in a liquid nitrogen bath using a lock-in amplifier technique. The prototype HV coil consisted of 26 continuous (without splice) single pancake coils concentrically centered on a stainless steel former. For ac loss measurement purposes, voltage tap pairs were soldered across each set of two single pancake coils so that a total of 13 separate voltage measurements could be made across the entire length of the coil. AC loss measurements were taken as a function of ac excitation current. Results show that the loss is primarily concentrated at the ends of the coil where the operating fraction of critical current is the highest and show a distinct difference in current scaling of the losses between low current and high current regimes.

  2. Measurements of AC Losses and Current Distribution in Superconducting Cables

    SciTech Connect

    Nguyen, Doan A; Ashworth, Stephen P; Duckworth, Robert C; Carter, Bill; Fleshler, Steven

    2011-01-01

    This paper presents our new experimental facility and techniques to measure ac loss and current distribution between the layers for High Temperature Superconducting (HTS) cables. The facility is powered with a 45 kVA three-phase power supply which can provide three-phase currents up to 5 kA per phase via high current transformers. The system is suitable for measurements at any frequency between 20 and 500 Hz to better understand the ac loss mechanisms in HTS cables. In this paper, we will report techniques and results for ac loss measurements carried out on several HTS cables with and without an HTS shielding layer. For cables without a shielding layer, care must be taken to control the effect of the magnetic fields from return currents on loss measurements. The waveform of the axial magnetic field was also measured by a small pick-up coil placed inside a two-layer cable. The temporal current distribution between the layers can be calculated from the waveform of the axial field.

  3. Calorimetric method of ac loss measurement in a rotating magnetic field.

    PubMed

    Ghoshal, P K; Coombs, T A; Campbell, A M

    2010-07-01

    A method is described for calorimetric ac-loss measurements of high-T(c) superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines. PMID:20687748

  4. Calorimetric method of ac loss measurement in a rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Ghoshal, P. K.; Coombs, T. A.; Campbell, A. M.

    2010-07-01

    A method is described for calorimetric ac-loss measurements of high-Tc superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines.

  5. Calorimetric method of ac loss measurement in a rotating magnetic field

    SciTech Connect

    Ghoshal, P. K.; Coombs, T. A.; Campbell, A. M.

    2010-07-15

    A method is described for calorimetric ac-loss measurements of high-T{sub c} superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines.

  6. Second VAMAS a.c. loss measurement intercomparison: a.c. magnetization measurement of hysteresis and coupling losses in NbTi multifilamentary strands

    NASA Astrophysics Data System (ADS)

    Schmidt, C.; Itoh, K.; Wada, H.

    The article summarizes results of part of the second VAMAS a.c. loss measurement intercomparison. This program was carried out at 17 participating laboratories on two sets of multifilamentary NbTi strands (Set No. 1: copper matrix, fil. diam. between 0.5 and 12 μm; Set No. 2: cupronickel matrix, fil. diam. between 0.4 and 1.2 μm). The results reported here were measured by means of a.c. magnetization methods and separated into hysteresis and coupling losses. One laboratory used a calorimetric method. The data scatter in measured hysteresis losses among the participating laboratories was reasonably small for different measuring methods adopted and experimental arrangements used. On the other hand, the data scatter in coupling losses was large, mainly because in most laboratories a.c. losses were measured only at low frequencies (below 1 Hz), where the separation of coupling losses from total losses tends to be inaccurate. The comparison of measured hysteresis losses with the critical state model showed a large disagreement, which is assumed to be due to proximity effect coupling between filaments. 1997 Elsevier Science Limited

  7. Measurements and calculations of transport AC loss in second generation high temperature superconducting pancake coils

    NASA Astrophysics Data System (ADS)

    Yuan, Weijia; Coombs, T. A.; Kim, Jae-Ho; Han Kim, Chul; Kvitkovic, Jozef; Pamidi, Sastry

    2011-12-01

    Theoretical and experimental AC loss data on a superconducting pancake coil wound using second generation (2 G) conductors are presented. An anisotropic critical state model is used to calculate critical current and the AC losses of a superconducting pancake coil. In the coil there are two regions, the critical state region and the subcritical region. The model assumes that in the subcritical region the flux lines are parallel to the tape wide face. AC losses of the superconducting pancake coil are calculated using this model. Both calorimetric and electrical techniques were used to measure AC losses in the coil. The calorimetric method is based on measuring the boil-off rate of liquid nitrogen. The electric method used a compensation circuit to eliminate the inductive component to measure the loss voltage of the coil. The experimental results are consistent with the theoretical calculations thus validating the anisotropic critical state model for loss estimations in the superconducting pancake coil.

  8. AC loss measurements in HTS coil assemblies with hybrid coil structures

    NASA Astrophysics Data System (ADS)

    Jiang, Zhenan; Long, Nicholas J.; Staines, Mike; Badcock, Rodney A.; Bumby, Chris W.; Buckley, Robert G.; Amemiya, Naoyuki

    2016-09-01

    Both AC loss and wire cost in coil windings are critical factors for high temperature superconductor (HTS) AC machinery applications. We present AC loss measurement results in three HTS coil assemblies at 77 K and 65 K which have a hybrid coil structure comprising one central winding (CW) and two end windings (EWs) wound with ReBCO and BSCCO wires with different self-field I c values at 77 K. All AC loss results in the coil assemblies are hysteretic and the normalized AC losses in the coil assemblies at different temperatures can be scaled with the I c value of the coil assemblies. The normalised results show that AC loss in a coil assembly with BSCCO CW can be reduced by using EWs wound with high I c ReBCO wires, whilst further AC loss reduction can be achieved by replacing the BSCCO CW with ReBCO CW. The results imply that a flexible hybrid coil structure is possible which considers both AC loss and wire cost in coil assemblies.

  9. AC loss measurement of superconducting dipole magnets by the calorimetric method

    SciTech Connect

    Morita, Y.; Hara, K.; Higashi, N.; Kabe, A.

    1996-12-31

    AC losses of superconducting dipole magnets were measured by the calorimetric method. The magnets were model dipole magnets designed for the SSC. These were fabricated at KEK with 50-mm aperture and 1.3-m overall length. The magnet was set in a helium cryostat and cooled down to 1.8 K with 130 L of pressurized superfluid helium. Heat dissipated by the magnet during ramp cycles was measured by temperature rise of the superfluid helium. Heat leakage into the helium cryostat was 1.6 W and was subtracted from the measured heat to obtain AC loss of the magnet. An electrical measurement was carried out for calibration. Results of the two methods agreed within the experimental accuracy. The authors present the helium cryostat and measurement system in detail, and discuss the results of AC loss measurement.

  10. Second VAMAS a.c. loss measurement intercomparison: magnetization measurement of low-frequency (hysteretic) a.c. loss in NbTi multifilamentary strands

    NASA Astrophysics Data System (ADS)

    Collings, E. W.; Sumption, M. D.; Itoh, K.; Wada, H.; Tachikawa, K.

    The results of the 2 nd VAMAS measurement intercomparison program on low-frequency (hysteretic) a.c. loss are presented and discussed. Two sets of multifilamentary NbTi strands (Set No. 1: copper matrix, fil. diams 0.5, 1, 3, and 12 μm; Set No. 2: cupronickel matrix, fil. diams 0.4, 0.5, and 1 μm) were subjected to interlaboratory testing. In an initial series of tests, samples in various forms (e.g. wire bundles, coils) were measured mostly by vibrating-sample- and SQUID magnetometry. Considerable scatter was noted especially in the small-filament-diameter a.c.-loss data. In a study of measurement accuracy, a supplementary series of tests compared the results of VSM measurement of a given pair of copper-matrix samples. In the light of all the results, factors contributing to a.c. loss error are discussed and recommendations are made concerning the specification of future a.c.-loss measurement intercomparisons.

  11. Modelling and measurement of ac loss in BSCCO/Ag-tape windings

    NASA Astrophysics Data System (ADS)

    Oomen, M. P.; Nanke, R.; Leghissa, M.

    2003-03-01

    High-temperature superconducting (HTS) transformers promise decreased weight and volume and higher efficiency. A 1 MVA HTS railway transformer was built and tested at Siemens AG. This paper deals with the prediction of ac loss in the BSCCO/Ag-tape windings. In a railway transformer the tape carries ac current in alternating field, the temperature differs from 77 K, tapes are stacked or cabled and overcurrents and higher harmonics occur. In ac-loss literature these issues are treated separately, if at all. We have developed a model that predicts the ac loss in sets of BSCCO/Ag-tape coils, and deals with the above-mentioned issues. The effect of higher harmonics on the loss in HTS tapes is considered for the first time. The paper gives a complete overview of the model equations and required input parameters. The model is validated over a wide range of the input parameters, using the measured critical current and ac loss of single tapes, single coils and sets of coils in the 1 MVA transformer. An accuracy of around 25% is achieved in all relevant cases. Presently the model is developed further, in order to describe other HTS materials and other types of applications.

  12. Ac-loss measurement of a DyBCO-Roebel assembled coated conductor cable (RACC)

    NASA Astrophysics Data System (ADS)

    Schuller, S.; Goldacker, W.; Kling, A.; Krempasky, L.; Schmidt, C.

    2007-10-01

    Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature around 50-77 K, which is a crucial precondition for economical cooling costs. We prepared a short length of a Roebel bar cable made of industrial DyBCO coated conductor (Theva Company, Germany). Meander shaped tapes of 4 mm width with a twist pitch of 122 mm were cut from 10 mm wide CC tapes using a specially designed tool. Eleven of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac field were measured as a function of frequency and field amplitude in transverse and parallel field orientations. In addition, the coupling current time constant of the sample was directly measured.

  13. Superconductor coil geometry and ac losses

    NASA Technical Reports Server (NTRS)

    Pierce, T. V., Jr.; Zapata, R. N.

    1976-01-01

    An empirical relation is presented which allows simple computation of volume-averaged winding fields from central fields for coils of small rectangular cross sections. This relation suggests that, in certain applications, ac-loss minimization can be accomplished by use of low winding densities, provided that hysteresis losses are independent of winding density. The ac-loss measurements on coils wound of twisted multifilamentary composite superconductors show no significant dependence on ac losses on winding density, thus permitting the use of winding density as an independent design parameter in loss minimization.

  14. Calorimetric AC loss measurement of MgB2 superconducting tape in an alternating transport current and direct magnetic field

    NASA Astrophysics Data System (ADS)

    See, K. W.; Xu, X.; Horvat, J.; Cook, C. D.; Dou, S. X.

    2012-11-01

    Applications of MgB2 superconductors in electrical engineering have been widely reported, and various studies have been made to define their alternating current (AC) losses. However, studies on the transport losses with an applied transverse DC magnetic field have not been conducted, even though this is one of the favored conditions in applications of practical MgB2 tapes. Methods and techniques used to characterize and measure these losses have so far been grouped into ‘electrical’ and ‘calorimetric’ approaches with external conditions set to resemble the application conditions. In this paper, we present a new approach to mounting the sample and employ the calorimetric method to accurately determine the losses in the concurrent application of AC transport current and DC magnetic fields that are likely to be experienced in practical devices such as generators and motors. This technique provides great simplification compared to the pickup coil and lock-in amplifier methods and is applied to a long length (˜10 cm) superconducting tape. The AC loss data at 20 and 30 K will be presented in an applied transport current of 50 Hz under external DC magnetic fields. The results are found to be higher than the theoretical predictions because of the metallic fraction of the tape that contributes quite significantly to the total losses. The data, however, will allow minimization of losses in practical MgB2 coils and will be used in the verification of numerical coil models.

  15. AC loss in superconducting tapes and cables

    NASA Astrophysics Data System (ADS)

    Oomen, Marijn Pieter

    High-temperature superconductors are developed for use in power-transmission cables, transformers and motors. The alternating magnetic field in these devices causes AC loss, which is a critical factor in the design. The study focuses on multi-filament Bi-2223/Ag tapes exposed to a 50-Hz magnetic field at 77 K. The AC loss is measured with magnetic, electric and calorimetric methods. The results are compared to theoretical predictions based mainly on the Critical-State Model. The loss in high- temperature superconductors is affected by their characteristic properties: increased flux creep, high aspect ratio and inhomogeneties. Filament intergrowths and a low matrix resistivity cause a high coupling-current loss especially when the filaments are fully coupled. When the wide side of the tape is parallel to the external magnetic field, the filaments are decoupled by twisting. In a perpendicular field the filaments can be decoupled only by combining a short twist pitch with a transverse resistivity much higher than that of silver. The arrangement of the inner filaments determines the transverse resistivity. Ceramic barriers around the filaments cause partial decoupling in perpendicular magnetic fields at power frequencies. The resultant decrease in AC loss is greater than the accompanying decrease in critical current. With direct transport current in alternating magnetic field, the transport-current loss is well described with a new model for the dynamic resistance. The Critical- State Model describes well the magnetisation and total AC loss in parallel magnetic fields, at transport currents up to 0.7 times the critical current. When tapes are stacked face-to-face in a winding, the AC-loss density in perpendicular fields is greatly decreased due to the mutual shielding of the tapes. Coupling currents between the tapes in a cable cause an extra AC loss, which is reduced by a careful cable design. The total AC loss in complex devices with many tapes is generally well

  16. Corrosion loss measurement of boiler tubes in a waste incineration environment by A.C. impedance method

    SciTech Connect

    Matsunaga, Yasuo; Nakagawa, Kiyokazu

    1997-08-01

    To monitor the corrosion rate of materials of boiler tubes in simulated waste incineration environment, A.C. impedance measurements were carried out for Alloy 625, SUS347H and STBA24 embedded in NaCl- KCl- NaSO{sub 4}-K{sub 2}SO{sub 4}-Al{sub 2}O{sub 3} mixed synthetic ash deposit at 600 C. Though the ash includes some non-melting component, A.C. impedance measurements can be applied to evaluate corrosion rates in the same manner the corrosion of materials immersed in molten salts. Supposing the difference of impedance between the low frequency and high frequency ({Delta}R) as polarization resistance, a linear relation was obtained between 1/{Delta}R and corrosion losses in air, air-0.1 vol.% HCl and air-10vol.% H{sub 2}O atmospheres. The HCl addition in accelerated the corrosion of all specimens by reducing basicity of the molten salt. On the other hand, the H{sub 2}O addition reduced the corrosion of Alloy 625, but it accelerated the corrosion of SUS347H and STBA24.

  17. Ac loss modelling and measurement of superconducting transformers with coated-conductor Roebel-cable in low-voltage winding

    NASA Astrophysics Data System (ADS)

    Pardo, Enric; Staines, Mike; Jiang, Zhenan; Glasson, Neil

    2015-11-01

    Power transformers using a high temperature superconductor (HTS) ReBCO coated conductor and liquid nitrogen dielectric have many potential advantages over conventional transformers. The ac loss in the windings complicates the cryogenics and reduces the efficiency, and hence it needs to be predicted in its design, usually by numerical calculations. This article presents detailed modelling of superconducting transformers with Roebel cable in the low-voltage (LV) winding and a high-voltage (HV) winding with more than 1000 turns. First, we model a 1 MVA 11 kV/415 V 3-phase transformer. The Roebel cable solenoid forming the LV winding is also analyzed as a stand-alone coil. Agreement between calculations and experiments of the 1 MVA transformer supports the model validity for a larger tentative 40 MVA 110 kV/11 kV 3-phase transformer design. We found that the ac loss in each winding is much lower when it is inserted in the transformer than as a stand-alone coil. The ac loss in the 1 and 40 MVA transformers is dominated by the LV and HV windings, respectively. Finally, the ratio of total loss over rated power of the 40 MVA transformer is reduced below 40% of that of the 1 MVA transformer. In conclusion, the modelling tool in this work can reliably predict the ac loss in real power applications.

  18. Inter-strand current sharing and ac loss measurements in superconducting YBCO Roebel cables

    SciTech Connect

    Majoros, M.; Sumption, M. D.; Collings, E. W.; Long, N. J.

    2015-04-08

    A Roebel cable, one twist pitch long, was modified from its as-received state by soldering copper strips between the strands to provide inter-strand connections enabling current sharing. Various DC transport currents (representing different percentages of its critical current) were applied to a single strand of such a modified cable at 77 K in a liquid nitrogen bath. Simultaneous monitoring of I–V curves in different parts of the strand as well as in its interconnections with other strands was made using a number of sensitive Keithley nanovoltmeters in combination with a multichannel high-speed data acquisition card, all controlled via LabView software. Current sharing onset was observed at about 1.02 of strand Ic. At a strand current of 1.3Ic about 5% of the current was shared through the copper strip interconnections. A finite element method modeling was performed to estimate the inter-strand resistivities required to enable different levels of current sharing. The relative contributions of coupling and hysteretic magnetization (and loss) were compared, and for our cable and tape geometry, and at dB/dt=1 T s-1, and our inter-strand resistance of 0.77 mΩ, (enabling a current sharing of 5% at 1.3Ic) the coupling component was 0.32% of the hysteretic component. However, inter-strand contact resistance values of 100–1000 times smaller (close to those of NbTi and Nb3Sn based accelerator cables) would make the coupling components comparable in size to the hysteretic components.

  19. Inter-strand current sharing and ac loss measurements in superconducting YBCO Roebel cables

    DOE PAGESBeta

    sumption, Mike; Majoros, Milan; Collings, E. W.; Van der Laan, D. C.

    2014-11-07

    A Roebel cable, one twist pitch long, was modified from its as-received state by soldering copper strips between the strands to provide inter-strand connections enabling current sharing. Various DC transport currents (representing different percentages of its critical current) were applied to a single strand of such a modified cable at 77 K in a liquid nitrogen bath. Simultaneous monitoring of I–V curves in different parts of the strand as well as in its interconnections with other strands was made using a number of sensitive Keithley nanovoltmeters in combination with a multichannel high-speed data acquisition card, all controlled via LabView software.more » Current sharing onset was observed at about 1.02 of strand Ic. At a strand current of 1.3Ic about 5% of the current was shared through the copper strip interconnections. A finite element method modeling was performed to estimate the inter-strand resistivities required to enable different levels of current sharing. The relative contributions of coupling and hysteretic magnetization (and loss) were compared, and for our cable and tape geometry, and at dB/dt=1 T s-1, and our inter-strand resistance of 0.77 mΩ, (enabling a current sharing of 5% at 1.3Ic ) the coupling component was 0.32% of the hysteretic component. However, inter-strand contact resistance values of 100–1000 times smaller (close to those of NbTi and Nb3Sn based accelerator cables) would make the coupling components comparable in size to the hysteretic components.« less

  20. Inter-strand current sharing and ac loss measurements in superconducting YBCO Roebel cables

    DOE PAGESBeta

    Majoros, M.; Sumption, M. D.; Collings, E. W.; Long, N. J.

    2015-04-08

    A Roebel cable, one twist pitch long, was modified from its as-received state by soldering copper strips between the strands to provide inter-strand connections enabling current sharing. Various DC transport currents (representing different percentages of its critical current) were applied to a single strand of such a modified cable at 77 K in a liquid nitrogen bath. Simultaneous monitoring of I–V curves in different parts of the strand as well as in its interconnections with other strands was made using a number of sensitive Keithley nanovoltmeters in combination with a multichannel high-speed data acquisition card, all controlled via LabView software.more » Current sharing onset was observed at about 1.02 of strand Ic. At a strand current of 1.3Ic about 5% of the current was shared through the copper strip interconnections. A finite element method modeling was performed to estimate the inter-strand resistivities required to enable different levels of current sharing. The relative contributions of coupling and hysteretic magnetization (and loss) were compared, and for our cable and tape geometry, and at dB/dt=1 T s-1, and our inter-strand resistance of 0.77 mΩ, (enabling a current sharing of 5% at 1.3Ic) the coupling component was 0.32% of the hysteretic component. However, inter-strand contact resistance values of 100–1000 times smaller (close to those of NbTi and Nb3Sn based accelerator cables) would make the coupling components comparable in size to the hysteretic components.« less

  1. Inter-strand current sharing and ac loss measurements in superconducting YBCO Roebel cables

    NASA Astrophysics Data System (ADS)

    Majoros, M.; Sumption, M. D.; Collings, E. W.; Long, N. J.

    2015-05-01

    A Roebel cable, one twist pitch long, was modified from its as-received state by soldering copper strips between the strands to provide inter-strand connections enabling current sharing. Various DC transport currents (representing different percentages of its critical current) were applied to a single strand of such a modified cable at 77 K in a liquid nitrogen bath. Simultaneous monitoring of I-V curves in different parts of the strand as well as in its interconnections with other strands was made using a number of sensitive Keithley nanovoltmeters in combination with a multi-channel high-speed data acquisition card, all controlled via LabView software. Current sharing onset was observed at about 1.02 of strand Ic. At a strand current of 1.3Ic about 5% of the current was shared through the copper strip interconnections. A finite element method modeling was performed to estimate the inter-strand resistivities required to enable different levels of current sharing. The relative contributions of coupling and hysteretic magnetization (and loss) were compared, and for our cable and tape geometry, and at dB/dt = 1 T s-1, and our inter-strand resistance of 0.77 mΩ, (enabling a current sharing of 5% at 1.3Ic ) the coupling component was 0.32% of the hysteretic component. However, inter-strand contact resistance values of 100-1000 times smaller (close to those of NbTi and Nb3Sn based accelerator cables) would make the coupling components comparable in size to the hysteretic components.

  2. Inter-strand current sharing and ac loss measurements in superconducting YBCO Roebel cables

    SciTech Connect

    sumption, Mike; Majoros, Milan; Collings, E. W.; Van der Laan, D. C.

    2014-11-07

    A Roebel cable, one twist pitch long, was modified from its as-received state by soldering copper strips between the strands to provide inter-strand connections enabling current sharing. Various DC transport currents (representing different percentages of its critical current) were applied to a single strand of such a modified cable at 77 K in a liquid nitrogen bath. Simultaneous monitoring of I–V curves in different parts of the strand as well as in its interconnections with other strands was made using a number of sensitive Keithley nanovoltmeters in combination with a multichannel high-speed data acquisition card, all controlled via LabView software. Current sharing onset was observed at about 1.02 of strand Ic. At a strand current of 1.3Ic about 5% of the current was shared through the copper strip interconnections. A finite element method modeling was performed to estimate the inter-strand resistivities required to enable different levels of current sharing. The relative contributions of coupling and hysteretic magnetization (and loss) were compared, and for our cable and tape geometry, and at dB/dt=1 T s-1, and our inter-strand resistance of 0.77 mΩ, (enabling a current sharing of 5% at 1.3Ic ) the coupling component was 0.32% of the hysteretic component. However, inter-strand contact resistance values of 100–1000 times smaller (close to those of NbTi and Nb3Sn based accelerator cables) would make the coupling components comparable in size to the hysteretic components.

  3. Ac loss calorimeter for three-phase cable

    SciTech Connect

    Daney, D.E.; Boenig, H.J.; Maley, M.P.; McMurry, D.E.; DeBlanc, B.G.

    1996-10-01

    A calorimeter for measuring ac losses in meter-long lengths of HTS superconducting power transmission line cables is described. The calorimeter, which is based on a temperature difference technique, has a precision of 1 mW and measures single, two-phase (coupling), and three-phase losses. The measurements show significant coupling losses between phases.

  4. Apparent ac losses in helical BiPbSrCaCuO-2223/Ag multifilamentary tape measured by different potential taps at power frequencies

    NASA Astrophysics Data System (ADS)

    Majoros, M.; Glowacki, B. A.; Campbell, A. M.; Han, Z.; Vase, P.

    1999-03-01

    Transport ac losses in BiPbSrCaCuO-2223/Ag multifilamentary tape in form of a helix with a 3 mm gap between the turns were measured in frequency range 40-125 Hz. Different positions of potential taps on outer and inner surface of the tape were used. Potential wires were led along the tape axis as well as along the axis of the helix. At currents lower than the critical current a strong dependence of measured apparent ac losses on potential taps position and on the form of potential wires was found. Suitably wound contact-less pick-up coils to detect magnetic flux of different magnetic field components were also used. They allowed us to measure the `magnetisation' part of apparent losses even when the sample was in resistive state, as well as the losses at the gap of the tape. Comparison of the losses at the gap of the tape with the existing theoretical model was made.

  5. AC resistance measuring instrument

    DOEpatents

    Hof, P.J.

    1983-10-04

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument. 8 figs.

  6. AC Resistance measuring instrument

    DOEpatents

    Hof, Peter J.

    1983-01-01

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument.

  7. Automated ac galvanomagnetic measurement system

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Espy, P. N.

    1985-01-01

    An automated, ac galvanomagnetic measurement system is described. Hall or van der Pauw measurements in the temperature range 10-300 K can be made at a preselected magnetic field without operator attendance. Procedures to validate sample installation and correct operation of other system functions, such as magnetic field and thermometry, are included. Advantages of ac measurements are discussed.

  8. Specific absorption rate dependence on temperature in magnetic field hyperthermia measured by dynamic hysteresis losses (ac magnetometry)

    NASA Astrophysics Data System (ADS)

    Garaio, Eneko; Sandre, Olivier; Collantes, Juan-Mari; Garcia, Jose Angel; Mornet, Stéphane; Plazaola, Fernando

    2015-01-01

    Magnetic nanoparticles (NPs) are intensively studied for their potential use for magnetic hyperthermia, a treatment that has passed a phase II clinical trial against severe brain cancer (glioblastoma) at the end of 2011. Their heating power, characterized by the ‘specific absorption rate (SAR)’, is often considered temperature independent in the literature, mainly because of the difficulties that arise from the measurement methodology. Using a dynamic magnetometer presented in a recent paper, we measure here the thermal dependence of SAR for superparamagnetic iron oxide (maghemite) NPs of four different size-ranges corresponding to mean diameters around 12 nm, 14 nm, 15 nm and 16 nm. The article reports a parametrical study extending from 10 to 60 {}^\\circ C in temperature, from 75 to 1031 kHz in frequency, and from 2 to 24 kA m-1 in magnetic field strength. It was observed that SAR values of smaller NPs decrease with temperature whereas for the larger sample (16 nm) SAR values increase with temperature. The measured variation of SAR with temperature is frequency dependent. This behaviour is fully explained within the scope of linear response theory based on Néel and Brown relaxation processes, using independent magnetic measurements of the specific magnetization and the magnetic anisotropy constant. A good quantitative agreement between experimental values and theoretical values is confirmed in a tri-dimensional space that uses as coordinates the field strength, the frequency and the temperature.

  9. Low ac loss geometries in YBCO coated conductors and impact on conductor stability

    SciTech Connect

    Duckworth, Robert C; List III, Frederick Alyious; Paranthaman, Mariappan Parans; Rupich, M. W.; Zhang, W.; Xie, Y. Y.; Selvamanickam, V.

    2007-01-01

    Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac fields up to 100 mT. While ac loss reduction was achieved with YBCO filaments created through laser scribing and inkjet deposition, the assembly of stacked YBCO conductor provides an alternative method of ac loss reduction. When compared to a 4-mm wide YBCO coated conductor with a critical current of 60 A, the ac loss in a stack of 2-mm wide YBCO coated conductors with a similar total critical current was reduced. While the reduction in ac loss in a 2-mm wide stack coincided with the reduction in the engineering current density of the conductor, further reduction of ac loss was obtained through the splicing of the 2-mm wide tapes with low resistance solders. To better determine the practicality of these methods from a stability point of view, a numerical analysis was carried out to determine the influence of bridging and splicing on stability of a YBCO coated conductor for both liquid nitrogen-cooled and conduction cooled geometries.

  10. ac-resistance-measuring instrument

    SciTech Connect

    Hof, P.J.

    1981-04-22

    An auto-ranging ac resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an ac excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance.

  11. The scaling of transport AC losses in Roebel cables with varying strand parameters

    NASA Astrophysics Data System (ADS)

    Jiang, Zhenan; Staines, Mike; Long, Nicholas J.; Badcock, Rodney A.; Bumby, Chris; Talantsev, Evgeny; Hamilton, Kent; Buckley, Robert G.; Amemiya, Naoyuki

    2014-07-01

    A Roebel cable is a good candidate for low-voltage windings in a high-temperature superconductor (HTS) transformer because of its high current-carrying capability and low AC loss. Transport AC loss measurements were carried out in 1.8 m long 15/5 (fifteen 5 mm wide strands) and 15/4 Roebel cables. The results were compared with those in many Roebel cables composed of 2 mm wide Roebel strands. Comparison of the AC losses hinted that the intrinsic difference in normalized transport AC losses is due to differences in the g/w (ratio of the horizontal gap between the Roebel strands over the Roebel strand width) values. The intrinsic difference was confirmed by measuring transport AC loss in a series of horizontally arranged parallel conductor pairs with various g values. A method to scale transport AC losses in Roebel cables with varying strand parameters was developed. The scaling method will be useful for a rough assessment of AC loss in one-layer solenoid winding coils, such as in a HTS transformer.

  12. Total AC loss study of 2G HTS coils for fully HTS machine applications

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Yuan, Weijia; Kvitkovic, Jozef; Pamidi, Sastry

    2015-11-01

    The application of HTS coils for fully HTS machines has become a new research focus. In the stator of an electrical machine, HTS coils are subjected to a combination of an AC applied current and AC external magnetic field. There is a phase shift between the AC current and AC magnetic field. In order to understand and estimate the total AC loss of HTS coils for electrical machines, we designed and performed a calorimetric measurement for a 2G HTS racetrack coil. Our measurement indicates that the total AC loss is greatly influenced by the phase shift between the applied current and the external magnetic field when the magnetic field is perpendicular to the tape surface. When the applied current and the external magnetic field are in phase, the total AC loss is the highest. When there is a 90 degree phase difference, the total AC loss is the lowest. In order to explain this phenomenon, we employ H formulation and finite element method to model the 2G HTS racetrack coil. Our calculation agrees well with experimental measurements. Two parameters are defined to describe the modulation of the total AC loss in terms of phase difference. The calculation further reveals that the influence of phase difference varies with magnetic field direction. The greatest influence of phase difference is in the perpendicular direction. The study provides key information for large-scale 2G HTS applications, e.g. fully HTS machines and superconducting magnetic energy storage, where the total AC loss subjected to both applied currents and external magnetic fields is a critical parameter for the design.

  13. Roebel assembled coated conductor cables (RACC): Ac-Losses and current carrying potential

    NASA Astrophysics Data System (ADS)

    Frank, A.; Heller, R.; Goldacker, W.; Kling, A.; Schmidt, C.

    2008-02-01

    Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature in the range 50-77 K. Ac-field applications require cables with low ac-losses and hence twisting of the individual strands. We solved this problem using the Roebel technique. Short lengths of Roebel bar cables were prepared from industrial DyBCO and YBCO-CC. Meander shaped tapes of 4 or 5 mm width with twist pitches of 123 or 127 mm were cut from the 10 or 12 mm wide CC tapes using a specially designed tool. Eleven or twelve of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac-field were measured as a function of frequency and field amplitude as well as the coupling current decay time constant. We discuss the results in terms of available theories and compare measured time constants in transverse field with measured coupling losses. Finally the potential of this cable type for ac-use is discussed with respect to ac-losses and current carrying capability.

  14. Structural and AC loss study for pure and doped MgB2 superconductor

    NASA Astrophysics Data System (ADS)

    Hansdah, J. S.; Sarun, P. M.

    2015-06-01

    Superconducting polycrystalline bulk MgB2 samples doped with n-C, n-Y2O3 and n-Ho2O3 were prepared by powder-in-sealed (PIST) method. XRD measurement shows the influence of dopants on phase and lattice parameters of samples. The ac susceptibility measurement reveals ac loss and activation energy of the samples. Nano-C doped sample shows less ac loss in all frequency (208 Hz - 999 Hz) among the doped samples; whereas n-Ho2O3 doped sample shows highest ac loss. The activation energy is high for rare earth (n-Y2O3 and n-Ho2O3) doped samples as compare to n-C doped samples which reveals the enhancement in flux-pinning properties of these materials.

  15. Structural and AC loss study for pure and doped MgB{sub 2} superconductor

    SciTech Connect

    Hansdah, J. S.; Sarun, P. M.

    2015-06-24

    Superconducting polycrystalline bulk MgB{sub 2} samples doped with n-C, n-Y{sub 2}O{sub 3} and n-Ho{sub 2}O{sub 3} were prepared by powder-in-sealed (PIST) method. XRD measurement shows the influence of dopants on phase and lattice parameters of samples. The ac susceptibility measurement reveals ac loss and activation energy of the samples. Nano-C doped sample shows less ac loss in all frequency (208 Hz – 999 Hz) among the doped samples; whereas n-Ho{sub 2}O{sub 3} doped sample shows highest ac loss. The activation energy is high for rare earth (n-Y{sub 2}O{sub 3} and n-Ho{sub 2}O{sub 3}) doped samples as compare to n-C doped samples which reveals the enhancement in flux-pinning properties of these materials.

  16. AC Loss Reduction in Filamentized YBCO Coated Conductors with Virtual Transverse Cross-cuts

    SciTech Connect

    Zhang, Yifei; Duckworth, Robert C; Ha, Tam T; List III, Frederick Alyious; Gouge, Michael J; Chen, Y; X, Xiong,; Selvamanickam, V.

    2011-01-01

    While the performance of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO)-based coated conductors under dc currents has improved significantly in recent years, filamentization is being investigated as a technique to reduce ac loss so that the 2nd generation (2G) high temperature superconducting (HTS) wires can also be utilized in various ac power applications such as cables, transformers and fault current limiters. Experimental studies have shown that simply filamentizing the superconducting layer is not effective enough to reduce ac loss because of incomplete flux penetration in between the filaments as the length of the tape increases. To introduce flux penetration in between the filaments more uniformly and further reduce the ac loss, virtual transverse cross-cuts were made in superconducting filaments of the coated conductors fabricated using the metal organic chemical vapor deposition (MOCVD) method. The virtual transverse cross-cuts were formed by making cross-cuts (17 - 120 {micro}m wide) on the IBAD (ion beam assisted deposition)-MgO templates using laser scribing followed by depositing the superconducting layer ({approx} 0.6 {micro}m thick). AC losses were measured and compared for filamentized conductors with and without the cross-cuts under applied peak ac fields up to 100 mT. The results were analyzed to evaluate the efficacy of filament decoupling and the feasibility of using this method to achieve ac loss reduction.

  17. Transport ac losses of a second-generation HTS tape with a ferromagnetic substrate and conducting stabilizer

    NASA Astrophysics Data System (ADS)

    Li, Shuo; Chen, Du-Xing; Fang, Jin

    2015-12-01

    The current-voltage curve and transport ac loss of a second-generation HTS tape with a ferromagnetic NiW substrate and brass stabilizer are measured. It is found that the ac loss is up to two orders of magnitude larger than what is expected by the power-law E(J) determined by the current-voltage curve and increases with increasing frequency. Modeling results show that the overly large ac loss is contributed by the ac loss in the HTS strip enhanced by the NiW substrate and the magnetic hysteresis loss in the substrate, and the frequency-dependent loss occurs in the brass layer covering the substrate but not in the ferromagnetic substrate itself as assumed previously. The ac loss in the brass layer is associated with transport currents but not eddy currents, and it has some features similar to ordinary eddy-current loss with significant differences.

  18. AC Loss Analysis on the Superconducting Coupling Magnet in MICE

    SciTech Connect

    Wu, Hong; Wang, Li; Green, Michael; Li, LanKai; Xu, FengYu; Liu, XiaoKun; Jia, LinXinag

    2008-07-08

    A pair of coupling solenoids is used in MICE experiment to generate magnetic field which keeps the muons within the iris of thin RF cavity windows. The coupling solenoids have a 1.5-meter inner diameter and will produce 7.4 T peak magnetic field. Three types of AC losses in coupling solenoid are discussed. The affect of AC losses on the temperature distribution within the cold mass during charging and rapid discharging process is analyzed also. The analysis result will be further confirmed by the experiment of the prototype solenoid for coupling solenoid, which will be designed, fabricated and tested at ICST.

  19. WITHDRAWN: Complex Study of Transport AC Loss in Various 2G HTS Racetrack Coils

    NASA Astrophysics Data System (ADS)

    Chen, Yiran; Zhang, Min; Chudy, Michal; Matsuda, Koichi; Coombs, Tim

    2013-06-01

    HTS racetrack coils are becoming important elements of an emerging number of superconducting devices such as generators or motors. In these devices the issue of AC loss is crucial, as performance and cooling power are derived from this quantity. This paper presents a comparative study of transport AC loss in two different types of 2G HTS racetrack coils. In this study, both experimental measurements and computer simulation approaches were employed. All the experiments were performed using classical AC electrical method. The finite-element computer model was used to estimate electromagnetic properties and calculate transport AC loss. The main difference between the characterized coils is covered inside tape architectures. While one coil uses tape based on RABITS magnetic substrate, the second coil uses a non-magnetic tape. Ferromagnetic loss caused by a magnetic substrate is an important issue involved in the total AC loss. As a result, the coil with the magnetic substrate surprised with high AC loss and rather low performance.

  20. Complex study of transport AC loss in various 2G HTS racetrack coils

    NASA Astrophysics Data System (ADS)

    Chen, Yiran; Zhang, Min; Chudy, Michal; Matsuda, Koichi; Coombs, Tim

    2013-04-01

    HTS racetrack coils are becoming important elements of an emerging number of superconducting devices such as generators or motors. In these devices the issue of AC loss is crucial, as performance and cooling power are derived from this quantity. This paper presents a comparative study of transport AC loss in two different types of 2G HTS racetrack coils. In this study, both experimental measurements and computer simulation approaches were employed. All the experiments were performed using classical AC electrical method. The finite-element computer model was used to estimate electromagnetic properties and calculate transport AC loss. The main difference between the characterized coils is covered inside tape architectures. While one coil uses tape based on RABITS magnetic substrate, the second coil uses a non-magnetic tape. Ferromagnetic loss caused by a magnetic substrate is an important issue involved in the total AC loss. As a result, the coil with the magnetic substrate surprised with high AC loss and rather low performance.

  1. Calculating AC Losses in High-temperature Superconducting Cables Comprising Coated Conductors

    NASA Astrophysics Data System (ADS)

    Noji, Hideki; Kawano, Shouta; Akaki, Yoji; Hamada, Tsugio

    In this study, we present a new calculation model of AC loss in a high-temperature superconducting (HTS) cable comprising coated conductors. AC loss is calculated by an electric circuit (EC) model. A previous EC model had three circuit elements: resistance as a function of the layer current, inductances related to the circumferential and axial fields. The new EC model has only inductances, and resistance is eliminated. In both models, AC loss of the coated conductor in each layer of an HTS cable is calculated on the basis of the Norris equation for a thin strip. The differences between measurement and calculations using the previous and new models are 12% and 14%, respectively, when transporting 1 kArms, which indicates that the new model is applicable for the calculation of AC loss in an HTS cable. These results indicate that layer current is dependent on inductances and not on resistance. The elimination of resistance simplifies AC loss calculation because it does not require repeated calculations for the convergence of the layer current. The calculation time was 1/20th of that of the previous model. In the new model, the Norris equation can be replaced with the calculation result obtained by the two-dimensional finite element method to obtain more accurate AC loss.

  2. Effect of Interfacial Resistance on AC Loss as a Function of Applied AC Field in YBCO Filamentary Conductors

    SciTech Connect

    Duckworth, Robert C; List III, Frederick Alyious; Zhang, Yifei

    2009-01-01

    To reduce ac loss in Y-Ba-Cu-O (YBCO) coated conductors while maintaining current sharing between filaments, an attempt was made to introduce an interfacial resistance between the YBCO filaments and a continuous silver cap layer. The YBCO filaments were produced via laser scribing of MOCVD YBCO films deposited on standard Ion Beam Assisted Deposition (IBAD) templates. After laser scribing, the filaments were exposed to air at room temperature to degrade the YBCO surface. A three micron thick silver cap layer was then and each sample was oxygen annealed at different temperature to produce different interface resistance at the interface between the silver and YBCO. Measurements of the ac loss was measured as a function of applied perpendicular field and frequency revealed a correlation between the reduction in coupling loss and the oxygen annealing temperature.

  3. Ac loss characteristics of YBCO superconducting tapes fabricated by TFA-MOD technique

    NASA Astrophysics Data System (ADS)

    Iwakuma, Masataka; Nigo, Masahiro; Inoue, Daisuke; Miyamoto, Naoya; Kiss, Takanobu; Funaki, Kazuo; Iijima, Yasuhiro; Saitoh, Takashi; Izumi, Teruo; Yamada, Yutaka; Shiohara, Yuu

    2005-10-01

    We investigated the ac loss properties of a YBCO superconducting tape fabricated by TFA-MOD technique. The thickness of the YBCO layer is 1.2 μm. A 6-tape stack of 50 mm in length and 10 mm in width was inserted into a saddle-shaped pickup coil. The ac loss was measured at 35-77 K by applying an external ac magnetic field. The magnetic field angle was changed by rotating the sample stack around its longitudinal axis. The effective penetration field, which corresponds to the breaking point of an ac loss curve, decreased with increasing field angle though it was much smaller than that which was estimated for a superconducting slab with the same thickness as the width of a tape. As a result, the ac loss increased monotonically with an increasing field angle against the wide surface for any amplitude. The observed field angular dependence of the ac loss agreed with the theoretically predicted one by using the observed ac losses in perpendicular magnetic field. Anyway the ac loss for a larger amplitude than the effective penetration field was proportional to the critical current density and the projective width of a tape in the direction of the applied magnetic field for any field angle and any temperature as well known. In addition we estimated the magnetic field, B, dependence of the critical current, Ic, from the observed magnetization curves. It was shown that zero-field Ic appeared to be a linear function of temperature and Ic-B characteristics was scaled with zero-field Ic. We also discussed a difference in Ic-B characteristics and its temperature dependence between TFA-MOD tapes and IBAD-PLD ones.

  4. Superconducting shielded core reactor with reduced AC losses

    DOEpatents

    Cha, Yung S.; Hull, John R.

    2006-04-04

    A superconducting shielded core reactor (SSCR) operates as a passive device for limiting excessive AC current in a circuit operating at a high power level under a fault condition such as shorting. The SSCR includes a ferromagnetic core which may be either closed or open (with an air gap) and extends into and through a superconducting tube or superconducting rings arranged in a stacked array. First and second series connected copper coils each disposed about a portion of the iron core are connected to the circuit to be protected and are respectively wound inside and outside of the superconducting tube or rings. A large impedance is inserted into the circuit by the core when the shielding capability of the superconducting arrangement is exceeded by the applied magnetic field generated by the two coils under a fault condition to limit the AC current in the circuit. The proposed SSCR also affords reduced AC loss compared to conventional SSCRs under continuous normal operation.

  5. Magnetization AC losses in MgB2 wires made by IMD process

    NASA Astrophysics Data System (ADS)

    Kováč, J.; Šouc, J.; Kováč, P.; Hušek, I.

    2015-01-01

    Magnetization AC losses of MgB2 superconductors with one and four filaments made by an internal magnesium diffusion (IMD) into boron process were measured and analyzed. For AC loss measurement a system based on a calibration-free method was used. Short samples of MgB2 wires were exposed to an external magnetic field with amplitudes up to 0.07 T, frequencies up to 1200 Hz, and a temperature range between 15 K and 40 K. A strong effect of eddy current losses was found in single-core wire containing pure copper sheath, which was proved by the same wire measurement after Cu etching. The impact of coupling current losses in non-twisted four-filament wire and the decoupling effect after twisting were observed. Coupling current losses in a low-frequency region were effectively reduced in agreement with theoretical assumption. The degradation of transport currents due to torsion stress by twisting was taken into account and the normalized AC losses of MgB2 wires made by IMD and powder-in-tube processes were compared. It appears that the IMD process is more perspective for AC applications due to much higher current densities and smaller degradation of current-carrying capability by twisting.

  6. AC magnetic field losses in BSCCO-2223 superconducting tapes

    SciTech Connect

    Lelovic, M.; Mench, S.; Deis, T.

    1997-09-01

    The AC magnetic losses at power frequencies (60 Hz) were investigated for mono- and multifilament Ag-sheathed (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (BSCCO-2223) tapes with similar transport critical current (I{sub c}) values at 77 K. The multifilament sample exhibited higher losses than the monofilament under the same conditions. Loss peaks are discussed in terms of intergranular, intragranular and eddy current losses. Because of BSCCO`s anisotropy, field orientation has a large effect on the magnitude of these peaks, even at relatively small angles. Losses for fields applied parallel to the c-axis of the textured BSCCO grains are larger by more than one order of magnitude than those applied perpendicular.

  7. Self-field ac losses in biaxially aligned Y{endash}Ba{endash}Cu{endash}O tape conductors

    SciTech Connect

    Iijima, Y.; Hosaka, M.; Sadakata, N.; Saitoh, T.; Kohno, O.; Takeda, K.

    1997-11-01

    Self-field ac losses were measured by the conventional ac four-probe method in biaxially aligned Y{endash}Ba{endash}Cu{endash}O tapes using polycrystalline Hastelloy tapes with textured yttria-stabilized-zirconia buffer layers. The ac losses increased in proportion to the fourth power of transport current in the high J{sub c} sample, and agreed well with Norris{close_quote} equation for thin strip conductors. However, the low J{sub c} sample had rather higher losses than Norris{close_quote} prediction, suggesting excessive magnetic flux penetration caused by percolated current paths. The results confirmed Norris{close_quote} prediction of the low ac losses for thin strip conductors, and indicated the importance of removing percolated structures of current paths to avoid higher ac losses than the theoretical predictions based on uniform conductors. {copyright} {ital 1997 American Institute of Physics.}

  8. Tevatron optics measurements using an AC dipole

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is a device to study beam optics of hadron synchrotrons. It can produce sustained large amplitude oscillations with virtually no emittance growth. A vertical AC dipole for the Tevatron is recently implemented and a maximum oscillation amplitude of 2{sigma} (4{sigma}) at 980 GeV (150 GeV) is achieved [1]. When such large oscillations are measured with the BPM system of the Tevatron (20 {micro}m resolution), not only linear but even nonlinear optics can be directly measured. This paper shows how to measure {beta} function using an AC dipole and the result is compared to the other measurement. The paper also shows a test to detect optics changes when small changes are made in the Tevatron. Since an AC dipole is nondestructive, it allows frequent measurements of the optics which is necessary for such an test.

  9. Distribution of AC loss in a HTS magnet for SMES with different operating conditions

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Tang, Y.; Ren, L.; Jiao, F.; Song, M.; Cao, K.; Wang, D.; Wang, L.; Dong, H.

    2013-11-01

    The AC loss induced in superconducting tape may affect the performance of a superconducting device applied to power system, such as transformer, cable, motor and even Superconducting Magnetic Energy Storage (SMES). The operating condition of SMES is changeable due to the need of compensation to the active or reactive power according to the demand of a power grid. In this paper, it is investigated that the distribution of AC loss for a storage magnet on different operating conditions, which is based on finite element method (FEM) and measured properties of BSCCO/Ag tapes. This analytical method can be used to optimize the SMES magnet.

  10. AC losses in prototype multistrand conductors for warm dielectric cable designs

    SciTech Connect

    Willis, J. O.; Maley, M. P.; Boening, H. J.; Coletta, G.; Mele, R.; Nassi, M.

    2002-01-01

    We report on multiphase ac losses in four-layer prototype multi-strand conductors (PMCs) wound from EITS tape provided by American Superconductor Corporation. These conductors are prototypes warm dielectric cable designs, such as for the US Dept. of Energy's Superconductivity Partnership Initiative Project at Detroit Edison, We report on single phase 'two phaset'(no current in Ihe PMC but with an external ac magnetic field generated by the two normal Conductors arranged at the remaining corners of an equilateral triangle forming a three-phase configuration) ,and balanced three phase losses. Losses were also measured using a set of saddle coils to apply an ac magnetic field to the PMC. The losses were measured as a function of temperature, frequency, and current. We compare the losses for three PMCs, one (4LA) wound conventionally with equal pitch angles for all layers and the two others (4LB and 4LC) wound to achieve equal current distribution (UCD) among the layers, and thus lower singlephase losses in the operating region. In addition, 4LC was wound with a newer gcneration tape having a higher critical current. The PMC 4LC was found to have the lowest single, twophase, and three-phase losses.

  11. Depinning of flux lines and AC losses in magnet-superconductor levitation system

    SciTech Connect

    Terentiev, A. N.; Hull, J. R.; De Long, L. E.

    1999-11-29

    The AC loss characteristics of a magnet-superconductor system were studied with the magnet fixed to the free end of an oscillating cantilever located near a stationary melt-textured YBCO pellet. Below a threshold AC field amplitude {approx}2Oe, the dissipation of the oscillator is amplitude-independent, characteristic of a linear, non-hysteretic regime. Above threshold,dissipation increases with amplitude, reflecting the depinning and hysteretic motion of flux lines. The threshold AC field is an order of magnitude higher than that measured for the same YBCO material via AC susceptometry in a uniform DC magnetic field, A partial lock-in of flux lines between YBCO ab planes is proposed as the mechanism for the substantial increase of the depinning threshold.

  12. AC Losses in the MICE Channel Magnets -- Is This a Curse or aBlessing?

    SciTech Connect

    Green, M.A.; Wu, H.; Wang, L.; Kai, L.L.; Jia, L.X.; Yang, S.Q.

    2008-01-31

    This report discusses the AC losses in the MICE channelmagnets during magnet charging and discharging. This report talks aboutthe three types of AC losses in the MICE magnets; the hysteretic AC lossin the superconductor, the coupling AC loss in the superconductor and theeddy current AC loss in the magnet mandrel and support structure. AClosses increase the heat load at 4 K. The added heat load increases thetemperature of the second stage of the cooler. In addition, AC losscontributes to the temperature rise between the second stage cold headand the high field point of the magnet, which is usually close to themagnet hot spot. These are the curses of AC loss in the MICE magnet thatcan limit the rate at which the magnet can be charge or discharged. Ifone is willing to allow some of the helium that is around the magnet toboil away during a magnet charge or discharge, AC losses can become ablessing. The boil off helium from the AC losses can be used to cool theupper end of the HTS leads and the surrounding shield. The AC losses arepresented for all three types of MICE magnets. The AC loss temperaturedrops within the coupling magnet are presented as an example of how boththe curse and blessing of the AC losses can be combined.

  13. 757 Path Loss Measurements

    NASA Technical Reports Server (NTRS)

    Horton, Kent; Huffman, Mitch; Eppic, Brian; White, Harrison

    2005-01-01

    Path Loss Measurements were obtained on three (3) GPS equipped 757 aircraft. Systems measured were Marker Beacon, LOC, VOR, VHF (3), Glide Slope, ATC (2), DME (2), TCAS, and GPS. This data will provide the basis for assessing the EMI (Electromagnetic Interference) safety margins of comm/nav (communication and navigation) systems to portable electronic device emissions. These Portable Electronic Devices (PEDs) include all devices operated in or around the aircraft by crews, passengers, servicing personnel, as well as the general public in the airport terminals. EMI assessment capability is an important step in determining if one system-wide PED EMI policy is appropriate. This data may also be used comparatively with theoretical analysis and computer modeling data sponsored by NASA Langley Research Center and others.

  14. AC-loss considerations of a pulse SMES for an accelerator

    NASA Astrophysics Data System (ADS)

    Lyly, M.; Hiltunen, I.; Järvelä, J.; Korpela, A.; Lehti, L.; Stenvall, A.; Mikkonen, R.

    2010-06-01

    In particle accelerators quasi-DC superconducting magnets are used to keep particles in desired tracks. The needed rapid field variations of these high energy magnets require large energy bursts. If these bursts are taken from and fed back to the utility grid, its voltage is distorted and the quality of the electricity degrades. In addition, these bursts may decrease operation life time of generators and extra arrangements may be required by the electricity producers. Thus, an energy storage is an essential component for a cost-effective particle accelerator. Flywheels, capacitors and superconducting magnetic energy storage (SMES) are possible options for these relatively large and high power energy storages. Here we concentrate on AC-loss of a pulse SMES aiming to demonstrate the feasibility of NbTi SMES in a particle accelerator. The designing of a SMES requires highly reliable AC-loss simulations. In this paper, calorimetric AC-loss measurements of a NbTi magnet have been carried out to consider conductor's suitability in a pulse SMES. In addition, the measured results are compared with AC-loss simulations.

  15. Hysteresis of sextupole and ac loss in Energy Doubler dipole magnets

    SciTech Connect

    Ishibashi, K.

    1982-06-18

    A simple model gave utilized for calculation of magnetization effects on ac loss and sextupole for Energy Doubler dipole magnets. The calculation in the simple model gave an underestimation of ac loss by about 30%. Results of computation on ac harmonics were also described.

  16. The influence of bending strains on AC power losses in multifilamentary BSCCO-2223/Ag tapes

    NASA Astrophysics Data System (ADS)

    Tsukamoto, O.; Ciszek, M.; Suzuki, H.; Ogawa, J.

    2006-08-01

    Recent advances in the manufacturing of multifilamentary high temperature superconducting composite wires allow for wider practical applications of the conductors, e.g. in power transmission cables, transformers and motors. The wires, based mainly on BSCCO-2223 and YBCO-123 cuprates, are used in the forms of variously shaped coils; therefore they are subjected to different kinds of mechanical stresses and strains. These, in turn, lead to some changes in the physical parameters of the superconducting material, mainly in the critical current density, and thus in the dissipated electromagnetic energy, when subjected to changing magnetic fields and transport currents. In this work we report some experimental results related to the AC loss characteristics of Bi-2223/Ag multifilamentary tapes and their dependences on bending strains. These losses are compared to the losses of virgin, straight tapes. The total AC losses, i.e. transport current and magnetization losses, in the Bi-2223/Ag tapes, were measured by means of the electrical and calorimetric methods. The experimental data obtained are compared with the critical state model predictions for AC loss behaviour in the experimental conditions presented here.

  17. Single and three-phase AC losses in HTS superconducting power transmission line prototype cables

    SciTech Connect

    Daney, D.E.; Boenig, H.J.; Maley, M.P.; Coulter, J.Y.; Fleshler, S.

    1997-11-01

    AC losses in two, one-meter-long lengths of HTS prototype multi-strand conductors (PMC`s) are measured with a temperature-difference calorimeter. Both single-phase and three-phase losses are examined with ac currents up to 1,000 A rms. The calorimeter, designed specifically for these measurements, has a precision of 1 mW. PMC {number_sign}1 has two helically-wound, non-insulated layers of HTS tape (19 tapes per layer), each layer wrapped with opposite pitch. PMC {number_sign}2 is identical except for insulation between the layers. The measured ac losses show no significant effect of interlayer insulation and depend on about the third power of the current--a result in agreement with the Bean-Norris model adapted to the double-helix configuration. The three-phase losses are a factor of two higher than those exhibited by a single isolated conductor, indicating a significant interaction between phases.

  18. Development of Low AC Loss TFA-MOD Coated Conductors

    NASA Astrophysics Data System (ADS)

    Katayama, K.; Machi, T.; Nakamura, T.; Takagi, Y.; Nakaoka, K.; Yoshizumi, M.; Izumi, T.; Shiohara, Y.

    TFA-MOD process is expected to be promising for future applications since it can produce high performance YBCO coated conductors (CCs) with low cost. Applying YBCO CCs to the power electric devices such as transformers and power cables, the reduction of alternating current (AC) loss for long wire is necessary. Multi-filamentation process, which is one of the most effective approaches for AC loss reduction, has been developed by the scribing process. We have developed the filamentation process using chemical etching. MOD derived CCs are, however, easily damaged in the chemical etching process due to existence of pores in a YBCO layer, resulting in critical current (Ic)-degradation and weak delamination strength. Consequently, it is difficult to scribe MOD derived CCs into 1mm-wide filaments for long length using the chemical etching process. Accordingly, we have studied a scribing process using an excimer laser without chemical etching. We defined P' value in this study as a function of irradiated laser power [J] divided by processing speed[m/s]. We studied relationship between the P' value and the results of scribing. It was found that we could scribe the C.C. with a sufficient depth in the condition of large P' value. Furthermore, we found that the Ic was degraded with further increase of the P' value. A 5 mm wide short sample was divided into 10 filaments by the excimer laser scribing process at the P' of 9[J/(m/s)]. The sample revealed reduction of the hysteresis loss down to 1/10 which could be expected from a theoretical prediction using the numbers of the filaments. Ic-degradation was suppressed as 28%, which was smaller than that of the scribed sample using chemical etching (Ic degradation was 38%). Subsequently, we applied the technique to a 100m long YBCO CC. The hysteresis loss of the 100m long MOD derived CC was reduced down to 1/10 (1/the number of filaments) after the multi-filamentation.

  19. The effect of surface grain reversal on the AC losses of sintered Nd-Fe-B permanent magnets

    NASA Astrophysics Data System (ADS)

    Moore, Martina; Roth, Stefan; Gebert, Annett; Schultz, Ludwig; Gutfleisch, Oliver

    2015-02-01

    Sintered Nd-Fe-B magnets are exposed to AC magnetic fields in many applications, e.g. in permanent magnet electric motors. We have measured the AC losses of sintered Nd-Fe-B magnets in a closed circuit arrangement using AC fields with root mean square-values up to 80 mT (peak amplitude 113 mT) over the frequency range 50 to 1000 Hz. Two magnet grades with different dysprosium content were investigated. Around the remanence point the low grade material (1.7 wt% Dy) showed significant hysteresis losses; whereas the losses in the high grade material (8.9 wt% Dy) were dominated by classical eddy currents. Kerr microscopy images revealed that the hysteresis losses measured for the low grade magnet can be mainly ascribed to grains at the sample surface with multiple domains. This was further confirmed when the high grade material was subsequently exposed to DC and AC magnetic fields. Here a larger number of surface grains with multiple domains are also present once the step in the demagnetization curve attributed to the surface grain reversal is reached and a rise in the measured hysteresis losses is evident. If in the low grade material the operating point is slightly offset from the remanence point, such that zero field is not bypassed, its AC losses can also be fairly well described with classical eddy current theory.

  20. Dependence of the ac loss on the aspect ratio in a cable in conduit conductor

    NASA Astrophysics Data System (ADS)

    Cau, F.; Bruzzone, P.

    2010-04-01

    The coupling current loss in rectangular superconducting cables is strictly dependent on their aspect ratio, which has an impact on the area linked by the field variation and consequently on the currents induced between strands. The relation between the ac loss and aspect ratio is studied with reference to the testing of three short cable in conduit conductor (CICC) samples at the SULTAN test facility. The first conductor is a 25 kA NbTi cable for the JT60-SA tokamak; the second is a 20 kA Nb3Sn cable for the HZB hybrid magnet. The last CICC is a 68 kA Nb3Sn cable with layout similar to that of the ITER toroidal field (TF) conductor (called the 'European toroidal field (EUTF) alternate'). All the samples are assembled with two conductor sections differing only in their orientation with respect to the external variable field. In the first and third samples, the cable of one leg is rotated by 90°, while in the HZB sample it is rotated by 45° with respect to the other leg. The ac loss is measured at the SULTAN test facility using a gas flow calorimetric method. A sample length of 39 cm is exposed to a sinusoidal field with an amplitude of ± 0.3 or ± 0.2 T (depending on the superconductor) and frequency variable in the range 0.1-0.8 Hz. A background field of 2 T perpendicular both to the sinusoidal field and to the sample axis is also applied. The ac loss is assessed by measuring the variation of the He enthalpy, assuming the metal enthalpy to be negligible. The loss curve for both legs is discussed in terms of the respective aspect ratios and the results, including data from former test campaigns, are compared with the aim of finding an analytical relation between the loss and the conductor dimensions.

  1. Inkjet printing of multifilamentary YBCO for low AC loss coated conductors

    NASA Astrophysics Data System (ADS)

    Hopkins, S. C.; Joseph, D.; Mitchell-Williams, T. B.; Calleja, A.; Vlad, V. R.; Vilardell, M.; Ricart, S.; Granados, X.; Puig, T.; Obradors, X.; Usoskin, A.; Falter, M.; Bäcker, M.; Glowacki, B. A.

    2014-05-01

    Considerable progress has been made with the development of REBCO coated conductors in recent years, and high performance conductors are available commercially. For many applications, however, the cost remains prohibitive, and AC losses discourage their selection for higher frequency applications. Chemical solution deposition (CSD) methods are attractive for low-cost, scalable preparation of buffer and superconductor layers, and in many respects inkjet printing is the method of choice, permitting non-contact deposition with minimal materials wastage and excellent control of coating thickness. Highly textured coatings of YBCO and Gd-doped CeO2 have previously been reported on buffered metal substrates. Inkjet printing also introduces the possibility of patterning - directly depositing two and three dimensional structures without subtractive processing - offering a low-cost route to coated conductors with reduced AC losses. In this contribution, the inkjet deposition of superconducting YBCO tracks is reported on industrially relevant buffered metal substrates both by direct printing and an inverse patterning approach. In the latter approach, ceria tracks were printed reported, which are a candidate both for resistive filament spacers and buffer layers. TFA-based precursor solutions have been printed on SS/ABAD-YSZ/CeO2 and Ni-W/LZO/CeO2 RABiTS substrates, and the resulting multifilamentary samples characterised by microscopy and scanning Hall probe measurements. The prospects for future inkjet-printed low AC loss coated conductors are discussed, including control of interfilamentary resistivity and bridging, transposed filamentary structures and stabilisation material.

  2. AC loss reduction of TFA-MOD coated conductors in long length by laser scribing technique

    NASA Astrophysics Data System (ADS)

    Katayama, K.; Hirano, H.; Machi, T.; Takagi, Y.; Takahashi, Y.; Izumi, T.

    TFA-MOD process is expected to be promising for future applications since it can produce high performance YBCO coated conductors with low cost. Applying YBCO coated conductors to the power electric devices such as transformer, cable, motors, reduction of AC loss for long wire is necessary. Multifilamentation, which is one of the effective approaches for AC loss reduction, has been developed by the scribing process. YBCO coated conductors produced by our standard TFA-MOD process delaminated into two parts by the laser scribing. The delamination was clarified to occur within the superconducting layer caused by the defects such as pores in the superconducting layer. In order to reduce the defects in the superconducting layer, we modify the heat treatment profile performed on the decomposed precursor films by applying the interim annealing(550-600°C) before crystallization heat treatment(740-770°C). The interim annealed samples had much less and smaller pores than the standard processed ones. The peel strength measured by transverse tensile test was as high as the PLD derived coated conductors which was successfully scribed into five filaments resulting in 1/5 AC loss. A 50m long YBCO coated conductor with the characteristics of 398A/cmwidth was obtained and cut into 5 mm width, followed by the laser scribing process into five filaments. The multifilamentation process was successfully performed without delamination throughout the wire. The hysteresis loss was down to 1/N (N: number of filaments), as we aimed. The IC properties of the filaments were 29±4A, indicating the wire was uniformly fabricated.

  3. Segmented superconducting tape having reduced AC losses and method of making

    DOEpatents

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Holesinger, Terry G.; Wang, Haiyan

    2009-09-22

    A superconducting tape having reduced AC losses. The tape has a high temperature superconductor layer that is segmented. Disruptive strips, formed in one of the tape substrate, a buffer layer, and the superconducting layer create parallel discontinuities in the superconducting layer that separate the current-carrying elements of the superconducting layer into strips or filament-like structures. Segmentation of the current-carrying elements has the effect of reducing AC current losses. Methods of making such a superconducting tape and reducing AC losses in such tapes are also disclosed.

  4. AC loss in high-temperature superconducting conductors, cables and windings for power devices

    NASA Astrophysics Data System (ADS)

    Oomen, M. P.; Rieger, J.; Hussennether, V.; Leghissa, M.

    2004-05-01

    High-temperature superconducting (HTS) transformers and reactor coils promise decreased weight and volume and higher efficiency. A critical design parameter for such devices is the AC loss in the conductor. The state of the art for AC-loss reduction in HTS power devices is described, starting from the loss in the single HTS tape. Improved tape manufacturing techniques have led to a significant decrease in the magnetization loss. Transport-current loss is decreased by choosing the right operating current and temperature. The role of tape dimensions, filament twist and resistive matrix is discussed and a comparison is made between state-of-the-art BSCCO and YBCO tapes. In transformer and reactor coils the AC loss in the tape is influenced by adjacent tapes in the coil, fields from other coils, overcurrents and higher harmonics. These factors are accounted for by a new AC-loss prediction model. Field components perpendicular to the tape are minimized by optimizing the coil design and by flux guidance pieces. High-current windings are made of Roebel conductors with transposed tapes. The model iteratively finds the temperature distribution in the winding and predicts the onset of thermal instability. We have fabricated and tested several AC windings and used them to validate the model. Now we can confidently use the model as an engineering tool for designing HTS windings and for determining the necessary tape properties.

  5. Ac hysteresis loop measurement of stator-tooth in induction motor

    SciTech Connect

    Son, D.

    1999-09-01

    The properties of ac hysteresis loop of a stator tooth in a 5 hp induction motor was measured and analyzed. The load increase on the motor decreased magnetic induction, however increase the minor hysteresis loops in the high induction region. This effect caused increase in the core loss. Depending on condition of the motor, the core loss of the stator tooth can be 50% greater than the core loss under sinusoidal magnetic induction waveform.

  6. Theory of AC Loss in Cables with 2G HTS Wire

    SciTech Connect

    Clem, J.R.; Malozemoff, A.P.

    2009-09-13

    While considerable work has been done to understand AC losses in power cables made of first generation (1G) high temperature superconductor (HTS) wires, use of second generation (2G) HTS wires brings in some new considerations. The high critical current density of the HTS layer 2G wire reduces the surface superconductor hysteretic losses. Instead, gap and polygonal losses, flux transfer losses in imbalanced two layer cables and ferromagnetic losses for wires with NiW substrates constitute the principal contributions. Current imbalance and losses associated with the magnetic substrate can be minimized by orienting the substrates of the inner winding inward and the outer winding outward.

  7. Measurement of coupling resonance driving terms with the AC dipole

    SciTech Connect

    Miyamoto, R.

    2010-10-01

    Resonance driving terms for linear coupled betatron motion in a synchrotron ring can be determined from corresponding spectral lines of an excited coherent beam motion. An AC dipole is one of instruments to excite such a motion. When a coherent motion is excited with an AC dipole, measured Courant-Snyder parameters and betatron phase advance have apparent modulations, as if there is an additional quadrupole field at the location of the AC dipole. Hence, measurements of these parameters using the AC dipole require a proper interpretation of observed quantities. The situation is similar in measurements of resonance driving terms using the AC dipole. In this note, we derive an expression of coupled betatron motion excited with two AC dipoles in presence of skew quadrupole fields, discuss an impact of this quadrupole like effect of the AC dipole on a measurement of coupling resonance driving terms, and present an analytical method to determine the coupling resonance driving terms from quantities observed using the AC dipole.

  8. Low AC Loss YBCO Coated Conductor Geometry by Direct Inkjet Printing

    SciTech Connect

    Rupich, Martin, Dr.; Duckworth, Robert, Dr.

    2009-10-01

    The second generation (2G) high temperature superconductors (HTS) wire offers potential benefits for many electric power applications, including ones requiring filamentized conductors with low ac loss, such as transformers and fault current limiters. However, the use of 2G wire in these applications requires the development of both novel multi-filamentary conductor designs with lower ac losses and the development of advanced manufacturing technologies that enable the low-cost manufacturing of these filamentized architectures. This Phase I SBIR project focused on testing inkjet printing as a potential low-cost, roll-to-roll manufacturing technique to fabricate potential low ac loss filamentized architectures directly on the 2G template strips.

  9. Critical field measurements in superconductors using ac inductive techniques

    NASA Astrophysics Data System (ADS)

    Campbell, S. A.; Ketterson, J. B.; Crabtree, G. W.

    1983-09-01

    The ac in-phase and out-of-phase response of type II superconductors is discussed in terms of dc magnetization curves. Hysteresis in the dc magnetization is shown to lead to a dependence of the ac response on the rate at which an external field is swept. This effect allows both Hc1 and Hc2 to be measured by ac techniques. A relatively simple mutual inductance bridge for making such measurements is described in the text, and factors affecting bridge sensitivity are discussed in the Appendix. Data for the magnetic superconductor ErRh4B4 obtained using this bridge are reported.

  10. AC current distribution and losses in multifilamentary superconductors exposed to longitudinal magnetic field

    SciTech Connect

    Le Naour, S.; Lacaze, A.; Laumond, Y.; Estop, P.; Verhaege, T.

    1996-07-01

    The current distribution and also AC losses, in a multifilamentary superconductor carrying a transport current, are influenced by the self and the external magnetic field. By using the Maxwell equations, a model has been developed in order to calculate the temporal evolution of current distribution in a single wire exposed or not to external magnetic field. This model is based on the actual relationship of electrical field E with current density J and takes into account the twist pitch of the wire. AC losses are calculated by adding all local losses through the cross section. This paper presents calculations of the influence of the cable twist coupled with the longitudinal magnetic field, and also gives some ideas how to decrease losses.

  11. Theory of ac loss in power transmission cables with second generation high temperature superconductor wires

    SciTech Connect

    Clem, J. R.; Malozemoff, A. P.

    2010-02-22

    While a considerable amount of work has been done in an effort to understand ac losses in power transmission cables made of first generation high temperature superconductor (HTS) wires, use of second generation (2G) HTS wires brings in some new considerations. The high critical current density of the HTS layer in 2G wires reduces the surface superconductor hysteretic losses, for which a new formula is derived. Instead, gap and polygonal losses, flux transfer losses in imbalanced two-layer cables and ferromagnetic losses for wires with NiW substrates constitute the principal contributions. A formula for the flux transfer losses is also derived with a paramagnetic approximation for the substrate. Current imbalance and losses associated with the magnetic substrate can be minimized by orienting the substrates of the inner winding inward and the outer winding outward.

  12. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    NASA Astrophysics Data System (ADS)

    Kajikawa, K.; Funaki, K.; Shikimachi, K.; Hirano, N.; Nagaya, S.

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean’s critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  13. AC losses in BiPbSrCaCuO-2223/Ag multifilamentary tapes in conditions similar to those in superconducting transmission lines

    NASA Astrophysics Data System (ADS)

    Majoros, M.; Glowacki, B. A.; Campbell, A. M.; Han, Z.; Vase, P.

    1998-12-01

    Transport AC losses in BiPbSrCaCuO-2223/Ag multifilamentary tape with 19 filaments were measured. The sample was 1.05 m long, wound in form of a helix with a gap between the tapes comparable with the tape width. Two different types of potential leads-tape following, axis following-with taps positioned in the centre of the tape were mounted on inner as well as outer surface of the helical sample. AC losses were measured at power frequencies by an electrical method using a lock-in nanovoltmeter. The influence of potential wires arrangement and the potential taps position on measured AC loss level and its frequency dependence was analysed.

  14. Artificial neural networks for AC losses prediction in superconducting round filaments

    NASA Astrophysics Data System (ADS)

    Leclerc, J.; Makong Hell, L.; Lorin, C.; Masson, P. J.

    2016-06-01

    An extensive and fast method to estimate superconducting AC losses within a superconducting round filament carrying an AC current and subjected to an elliptical magnetic field (both rotating and oscillating) is presented. Elliptical fields are present in rotating machine stators and being able to accurately predict AC losses in fully superconducting machines is paramount to generating realistic machine designs. The proposed method relies on an analytical scaling law (ASL) combined with two artificial neural network (ANN) estimators taking 9 input parameters representing the superconductor, external field and transport current characteristics. The ANNs are trained with data generated by finite element (FE) computations with a commercial software (FlexPDE) based on the widely accepted H-formulation. After completion, the model is validated through comparison with additional randomly chosen data points and compared for simple field configurations to other predictive models. The loss estimation discrepancy is about 3% on average compared to the FEA analysis. The main advantages of the model compared to FE simulations is the fast computation time (few milliseconds) which allows it to be used in iterated design processes of fully superconducting machines. In addition, the proposed model provides a higher level of fidelity than the scaling laws existing in literature usually only considering pure AC field.

  15. AC losses in superconducting Nb{sub 3}Sn and NbTi CIC conductors

    SciTech Connect

    Oliva, A.B.; Baudouy, B.J.P.; Miller, J.; Van Sciver, S.W.

    1996-07-01

    AC losses measurements and calculation on large scale Cable-in-Conduit (CIC) conductors have been carried out at NHMFL. In particular samples of the Nb{sub 3}Sn and NbTi conductors developed for the NHMFL 45-T Hybrid Magnet superconducting outsert have been tested. A calorimetric technique involving superfluid helium (He II) has been used. The samples have been tested with applied field variation rates varying in the range between 0.01 T/s to 30 T/s. From results it appears that for most of the samples, at high field variation rates, the coupling currents are so intense to locally saturate the superconducting strands. As no theories describing the saturation regime in CIC conductors exist, the authors tried to extend the theories developed for monolithic conductors to the more complicated CICC geometry. It emerges by defining an effective coupling time constant and an effective radius for the conductor that it is possible to fit the data with good accuracy. Effective coupling time constant and an effective radius for the conductor that it is possible to fit the data with good accuracy. Effective coupling time constants between 3 ms and 200 ms, depending on the strands surface condition and the cable void fraction, have been measured for the Nb{sub 3}Sn conductors, while a time constant of 16 ms has been determined for the NbTi sample. The experimental results and the theoretical analysis are reported in the paper.

  16. Measuring Bearing Wear Via Weight Loss

    NASA Technical Reports Server (NTRS)

    Keba, John E.; Moore, Richard S.

    1989-01-01

    Wear in critical parts of bearings measured via amounts of weight lost during use. Technique applicable in general to bearings made of nonporous materials. Weight-loss measurements easier, faster, more precise, and less likely to damage measured parts. Weight-loss measurements performed in clean rooms and under constraint of extreme cleanliness for compatability with liquid oxygen.

  17. Transport and AC loss properties of the repaired multifilamentary REBCO superconducting tapes

    NASA Astrophysics Data System (ADS)

    Yamasaki, S.; Iwakuma, M.; Funaki, K.; Kato, J.; Chikumoto, T.; Tanabe, K.; Nakao, K.; Izumi, T.; Yamada, Y.; Shiohara, Y.; Saito, T.

    2010-11-01

    For near-future applications of REBa 2Cu 3O 7 (REBCO) coated conductors to electric power cables, transformers and Superconducting Magnetic Energy Storage (SMES), the long taped wires with high performance in the transport properties have been designed and fabricated. Moreover, in order to drastically reduce AC losses in perpendicular field configuration, advanced multifilament YBCO coated conductors (MFYCCs) fabricated with technique of a laser scribing process have been also developed. In the present study, from engineering viewpoints to utilize such advanced conductors, we evaluated the transport and AC loss properties of short MFYCCs with a repaired part or a joint by a diffusion joint technique with the saddle-shaped pickup coil method.

  18. Numerical study on AC loss characteristics of superconducting power transmission cables comprising coated conductors with magnetic substrates

    NASA Astrophysics Data System (ADS)

    Amemiya, N.; Nakahata, M.

    2007-10-01

    Electromagnetic field analyses were made for mono-layer conductors comprising coated conductors for superconducting power transmission cables in order to evaluate their AC loss characteristics. We focused on the magnetic properties of the substrates of coated conductors. The current distribution in each coated conductor and the magnetic flux profile around each coated conductor were visualized. The influence of relative permeability and the space between coated conductors on the AC loss characteristics of mono-layer conductors were studied based on the visualized current and magnetic flux distributions. The influence of a saturated magnetic property on a calculated AC loss was also discussed.

  19. An improved FEM model for computing transport AC loss in coils made of RABiTS YBCO coated conductors for electric machines

    NASA Astrophysics Data System (ADS)

    Ainslie, Mark D.; Rodriguez-Zermeno, Victor M.; Hong, Zhiyong; Yuan, Weijia; Flack, Timothy J.; Coombs, Timothy A.

    2011-04-01

    AC loss can be a significant problem for any applications that utilize or produce an AC current or magnetic field, such as an electric machine. The authors investigate the electromagnetic properties of high temperature superconductors with a particular focus on the AC loss in superconducting coils made from YBCO coated conductors for use in an all-superconducting electric machine. This paper presents an improved 2D finite element model for the cross-section of such coils, based on the H formulation. The model is used to calculate the transport AC loss of a racetrack-shaped coil using constant and magnetic field-dependent critical current densities, and the inclusion and exclusion of a magnetic substrate, as found in RABiTS (rolling-assisted biaxially textured substrate) YBCO coated conductors. The coil model is based on the superconducting stator coils used in the University of Cambridge EPEC Superconductivity Group's all-superconducting permanent magnet synchronous motor design. To validate the modeling results, the transport AC loss of a stator coil is measured using an electrical method based on inductive compensation by means of a variable mutual inductance. Finally, the implications of the findings on the performance of the motor are discussed.

  20. Approach for Wide Use of Diagnostic Method for XLPE Cables Using Harmonics in AC Loss Current

    NASA Astrophysics Data System (ADS)

    Tsujimoto, Tomiyuki; Nakade, Masahiko; Yagi, Yukihiro; Ishii, Noboru

    Water tree is one of the degradation aspects of XLPE cables used for under-ground distribution or transmission lines. We have developed the loss current method using 3rd harmonic in AC loss current for cable diagnosis. Harmonic components in loss current arise as a result of the non-linear voltage-current characteristics of water trees. We confirmed that the 3rd harmonic in AC loss current had good correlation with water tree growth and break down strength. After that, we have applied this method to the actual 66kV XLPE cable lines. Up to now, the number of the application results is more than 130 lines. In case of cable lines terminated at gas-insulated switchgear (GIS), we have to remove the lightning arrestor (LA) and the potential transformer (PT) out of the test circuit. The reason is that we are afraid that each of LA and PT disturbs the degradation signal from cable lines. It takes extra time (1 or 2 days) and costs more to remove LA and PT in GIS out of a circuit. In order to achieve easy and reasonable diagnosis, we have developed a new method for cable lines terminated at GIS, by utilizing a technique, which enables to reduce signal of LA and PT from disturbed signal of cable lines. We confirmed the effect of the new method by experiments with actual cables.

  1. Measurement of the 225Ac half-life.

    PubMed

    Pommé, S; Marouli, M; Suliman, G; Dikmen, H; Van Ammel, R; Jobbágy, V; Dirican, A; Stroh, H; Paepen, J; Bruchertseifer, F; Apostolidis, C; Morgenstern, A

    2012-11-01

    The (225)Ac half-life was determined by measuring the activity of (225)Ac sources as a function of time, using various detection techniques: α-particle counting with a planar silicon detector at a defined small solid angle and in a nearly-2π geometry, 4πα+β counting with a windowless CsI sandwich spectrometer and with a pressurised proportional counter, gamma-ray spectrometry with a HPGe detector and with a NaI(Tl) well detector. Depending on the technique, the decay was followed for 59-141 d, which is about 6-14 times the (225)Ac half-life. The six measurement results were in good mutual agreement and their mean value is T(1/2)((225)Ac)=9.920 (3)d. This half-life value is more precise and better documented than the currently recommended value of 10.0 d, based on two old measurements lacking uncertainty evaluations. PMID:22940415

  2. Finite element analysis of current flowing patterns and AC loss in the multifilament strand

    NASA Astrophysics Data System (ADS)

    Ta, Wurui; Li, Yingxu; Gao, Yuanwen

    2013-12-01

    Intrinsic current flow and field distribution scheme under the imposed low current injection and the applied weak field is meaningful to interpret Ic degradation and AC loss in a strand that performs as a normal composite conductor. A 2D finite element (FE) transport model is built in COMSOL to identify the various transverse resistance components and reveal the interrelation among them. Then the transverse resistivity components are taken as the basic electrical components in a 3D composite strand model. The 3D model follows the realistic trajectories of twisted filaments in strand composite and experimental material properties. To address the potential/current map in the stationary transport, the FE model is thoroughly analyzed for the short-sample and long-sample strand, imposed by two in-plane steady current injections and a potential boundary condition at one strand end with the other end grounded, respectively. The results show that the short-sample longitudinal current is uniform with little resistivity loss, and flows from the positive source and converges to the negative one in the cross section with different paths and current proportions between filaments and matrix. However, for the long-sample, there is a serious reduction in electric potential along the strand axis and the currents mostly concentrate on filaments. The time-varying problem is also implemented by computing AC loss induced by a relatively far-away alternating line current. It is discussed where appropriate that the effect of the twist pitch and contact resistivity on the pattern and magnitude of the current flow and AC loss.

  3. AC loss in stacks of Bi-2223/Ag tapes modified with ferromagnetic covers at the edges

    NASA Astrophysics Data System (ADS)

    Safran, S.; Gömöry, F.; Gencer, Ali

    2010-10-01

    We investigated the magnetization loss of stacked Bi-2223/Ag tapes with a ferromagnetic cover on the edges. Such modification has been found recently to reduce the AC loss of a single tape; however, the behavior in a coil winding could be different. With experiments and numerical calculations we show that a ferromagnetic cover on the edges of a superconducting tape could reduce its magnetization loss also when the tapes are arranged in a stack. The effect is weaker for larger numbers of tapes but nevertheless remained significant in a stack of four tapes, which was the maximum number studied here. The effects observed experimentally are nicely explained by the results of numerical calculations.

  4. Ac45 silencing mediated by AAV-sh-Ac45-RNAi prevents both bone loss and inflammation caused by periodontitis

    PubMed Central

    Zhu, Zheng; Chen, Wei; Hao, Liang; Zhu, Guochun; Lu, Yun; Li, Sheng; Wang, Lin; Li, Yi-Ping

    2015-01-01

    Aim Periodontitis induced by oral pathogens leads to severe periodontal tissue damage and osteoclast-mediated bone resorption caused by inflammation. Based on the importance of Ac45 in osteoclast formation and function, we performed this study to evaluate the therapeutic potential of periodontitis by local adeno-associated virus (AAV)-mediated Ac45 gene knockdown. Material and Methods We used AAV-mediated short hairpin RNAi knockdown of Ac45 gene expression (AAV-sh-Ac45) to inhibit bone erosion and gingival inflammation simultaneously in a well-established periodontitis mouse model induced by Porphyromonas gingivalis W50. Histological studies were performed to evaluate the bone protection of AAV-sh-Ac45. Immunochemistry, ELISA and qRT-PCR were performed to reveal the role of Ac45 knockdown on inflammation, immune response and expression of cytokine. Results We found that Ac45 knockdown impaired osteoclast-mediated extracellular acidification and bone resorption in vitro and in vivo. Furthermore, local administration of AAV-sh-Ac45 protected mice from bone erosion by >85% and attenuated inflammation and decreased infiltration of T-cells, dendritic cells and macrophages in the periodontal lesion. Notably, the expression of pro-inflammatory cytokines was also reduced. Conclusions Local AAV-sh-Ac45 gene therapy efficiently protects against periodontal tissue damage and bone erosion through both inhibition of osteoclast function and attenuating inflammation, and may represent a powerful new treatment strategy for periodontitis. PMID:25952706

  5. ESBWR response to an extended station blackout/loss of all AC power

    SciTech Connect

    Barrett, A. J.; Marquino, W.

    2012-07-01

    U.S. federal regulations require light water cooled nuclear power plants to cope with Station Blackouts for a predetermined amount of time based on design factors for the plant. U.S. regulations define Station Blackout (SBO) as a loss of the offsite electric power system concurrent with turbine trip and unavailability of the onsite emergency AC power system. According to U.S. regulations, typically the coping period for an SBO is 4 hours and can be as long as 16 hours for currently operating BWR plants. Being able to cope with an SBO and loss of all AC power is required by international regulators as well. The U.S. licensing basis for the ESBWR is a coping period of 72 hours for an SBO based on U.S. NRC requirements for passive safety plants. In the event of an extended SBO (viz., greater than 72 hours), the ESBWR response shows that the design is able to cope with the event for at least 7 days without AC electrical power or operator action. ESBWR is a Generation III+ reactor design with an array of passive safety systems. The ESBWR primary success path for mitigation of an SBO event is the Isolation Condenser System (ICS). The ICS is a passive, closed loop, safety system that initiates automatically on a loss of power. Upon Station Blackout or loss of all AC power, the ICS begins removing decay heat from the Reactor Pressure Vessel (RPV) by (i) condensing the steam into water in heat exchangers located in pools of water above the containment, and (ii) transferring the decay heat to the atmosphere. The condensed water is then returned by gravity to cool the reactor again. The ICS alone is capable of maintaining the ESBWR in a safe shutdown condition after an SBO for an extended period. The fuel remains covered throughout the SBO event. The ICS is able to remove decay heat from the RPV for at least 7 days and maintains the reactor in a safe shutdown condition. The water level in the RPV remains well above the top of active fuel for the duration of the SBO event

  6. Flux Pinning and AC Loss in Second Generation High Temperature Superconductor Wires

    SciTech Connect

    Paranthaman, Mariappan Parans; Selvamanickam, V.

    2007-01-01

    Major advances have been made in the last 18 years in high-temperature superconductor (HTS) reserach and development, resulting in increased use of HTS materials in commerical and pre-commercial electric-power applications. This new and important book addresses the issues related to flux pinning, AC losses and thick YBCO film growth. Written by top most scientists in the world, it presents the current status and issues related to YBCO coated conductors and the need for further fundamental materials science work in YBCO coated conductor. It will be a useful handbook for years to come.

  7. Stability mechanical considerations, and AC loss in HTSC monoliths, coils, and wires

    NASA Technical Reports Server (NTRS)

    Sumption, M. D.; Collings, E. W.

    1995-01-01

    For monolithic high-T(sub c) superconductors (HTSC's) calculations are presented of: (1) the initial flux jump field, H(sub fj), in melt-processed YBCO based on a field and temperature dependent J(sub c), and (2) the radial and circumferential stresses in solid and hollow cylinders containing trapped magnetic flux. For model multi filamentary (MF) HTSC/Ag strands calculations are presented of: (1) the limiting filament diameters for adiabatic and dynamic stability, and (2) the hysteretic and eddy current components of AC loss. Again for MF HTSC/Ag composite strands the need for filamentary subdivision and twisting is discussed.

  8. Technique for reduction of mechanical losses in AC superconducting coils due to thermal expansion properties of various FRP bobbins

    NASA Astrophysics Data System (ADS)

    Sekine, N.; Tada, S.; Higuchi, T.; Furumura, Y.; Takao, T.; Yamanaka, A.

    2005-10-01

    We reported about reduction of mechanical losses in AC superconducting coils. The method is the use of FRP bobbins fabricated with special fibers. Since their FRPs have negative thermal expansion coefficient to the fiber direction, the FRP bobbins expand to the circumferential direction during cooling down. In case of the superconducting coils with such FRP bobbins, the winding tensions do not decrease during cooling down. Therefore, the mechanical losses are reduced by the suppression of wire's vibration. Their special FRPs are a Dyneema® fiber reinforced plastic (DFRP), a Dyneema and glass fiber reinforced plastic (DGFRP), and a Zylon® fiber reinforced plastic (ZFRP). These materials have negative thermal expansion coefficient to the fiber direction, however, the amplitudes of thermal expansion are various by the quantity or quality of the fiber. In this paper, the values of thermal expansion were actually measured, and it was discussed about the influence on the mechanical losses. At the experimental results, the mechanical loss was small, so that the thermal strain to the circumferential direction on the coil was large. Moreover, in case of the coils with sufficiently strong winding tensions at coil-operating temperature, the mechanical losses vanished.

  9. Calculating transport AC losses in stacks of high temperature superconductor coated conductors with magnetic substrates using FEM

    NASA Astrophysics Data System (ADS)

    Ainslie, Mark D.; Flack, Tim J.; Campbell, Archie M.

    2012-01-01

    In this paper, the authors investigate the electromagnetic properties of stacks of high temperature superconductor (HTS) coated conductors with a particular focus on calculating the total transport AC loss. The cross-section of superconducting cables and coils is often modeled as a two-dimensional stack of coated conductors, and these stacks can be used to estimate the AC loss of a practical device. This paper uses a symmetric two dimensional (2D) finite element model based on the H formulation, and a detailed investigation into the effects of a magnetic substrate on the transport AC loss of a stack is presented. The number of coated conductors in each stack is varied from 1 to 150, and three types of substrate are compared: non-magnetic weakly magnetic and strongly magnetic. The non-magnetic substrate model is comparable with results from existing models for the limiting cases of a single tape (Norris) and an infinite stack (Clem). The presence of a magnetic substrate increases the total AC loss of the stack, due to an increased localized magnetic flux density, and the stronger the magnetic material, the further the flux penetrates into the stack overall. The AC loss is calculated for certain tapes within the stack, and the differences and similarities between the losses throughout the stack are explained using the magnetic flux penetration and current density distributions in those tapes. The ferromagnetic loss of the substrate itself is found to be negligible in most cases, except for small magnitudes of current. Applying these findings to practical applications, where AC transport current is involved, superconducting coils should be wound where possible using coated conductors with a non-magnetic substrate to reduce the total AC loss in the coil.

  10. Localized power loss measurement using remote sensors

    SciTech Connect

    Moghaddam, A.J.; Moses, A.J. . Wolfson Centre for Magnetics Technology)

    1993-11-01

    A computerized system was designed and constructed to scan and measure localized power loss over an area of an electrical steel lamination. The local components of flux density (B) and field (H) were detected by a remote search coil and a magnetoresistive sensor respectively. The results obtained show that the power loss varies over the sample surface and the surface of individual grains. A high average loss was observed over a grain with a yaw angle of 7[degree], the minimum average loss was measured in a grain with a tilt angle of approximately 2[degree] to 3[degree]. The bulk average power loss over an area is comparable to that of a Single Strip Tester (SST).

  11. Energy loss measurement of cosmic ray muons

    NASA Astrophysics Data System (ADS)

    Unger, Joseph

    1993-02-01

    Measurements of energy losses of high energy cosmic ray muons in an ionization chamber are presented. The chamber consists of 16 single gap layers, and the liquid tetra methyl silane (TMS) was used as active medium. The absolute energy loss and the relativistic rise were measured and compared with theoretical calculations. The importance of the measurements within the framework of the cosmic ray experiment KASCADE (German acronym for Karlsruhe Shower Core and Array Detector) are discussed, especially with respect to energy calibration of hadrons and high energy muons above 1 TeV.

  12. Transport ac loss in a rectangular thin strip with power-law E (J) relation

    NASA Astrophysics Data System (ADS)

    Li, Shuo; Chen, Du-Xing; Fan, Yu; Fang, Jin

    2015-01-01

    Transport ac losses of a rectangular thin strip obeying relation E /Ec =(J /Jc) n with a fixed critical current Ic and n = 5, 10, 20, 30 , and 40 are accurately computed at a fixed frequency f as functions of the current amplitude Im . The results may be interpolated and scaled to those at any values of Ic, f , and 5 ⩽ n ⩽ 40 . Normalized in the same way as that in Norris' analytical formula derived from the critical-state model and converting f to a critical frequency fc , the modeling results may be better compared with the Norris formula and experimental data. A complete set of calculated modeling data are given with necessary formulas to be easily used by experimentalists in any particular case.

  13. Transport ac loss of elliptical thin strips with a power-law E(J) relation

    NASA Astrophysics Data System (ADS)

    Jia, Chen-Xi; Chen, Du-Xing; Li, Shuo; Fang, Jin

    2015-10-01

    The transport ac loss Q of an elliptical thin strip of critical current I c with a power-law relation E\\propto {J}n is accurately computed as a function of current amplitude I m and frequency f. The resulting Q({I}m) is normalized to q({i}m) following the Norris critical-state formula, and converted to {q}*({i}m*) at a critical frequency f c based on a transport scaling law. Having a set of {q}*({i}m*) at several values of n as a base, a general expression of {q}*({i}m*,n) is obtained, which can be used to easily calculate q({i}m) for any practical purposes.

  14. Analysis and comparison for rotor eddy current losses of permanent magnet synchronous generator according to dc and ac load conditions

    NASA Astrophysics Data System (ADS)

    Jang, Seok-Myeong; Kim, Hyun-Kyu; Choi, Jang-Young; Ko, Kyoung-Jin

    2009-04-01

    This paper presents an analytical procedure for the calculation of the eddy current losses of permanent magnet synchronous generator (PMSG). The dc and ac loading effects on the eddy current is examined through the suggested analytical procedure that considers the radial and tangential flux density waveform through a phase current harmonic analysis. The corresponding test results are also presented to quantify and compare those loading effects on the eddy current. The results verified the suggested analytical procedures and show that the rotor eddy current losses for PMSG with the dc loads turned out to be more significant than those with the ac loads.

  15. ac losses and field and current density distribution during a full cycle of a stack of superconducting tapes

    NASA Astrophysics Data System (ADS)

    Yuan, Weijia; Campbell, A. M.; Coombs, T. A.

    2010-05-01

    Starting from an existing model by Clem et al., this paper has analyzed how the current density and magnetic field distribution of a stack of superconducting tapes with ac transport currents or applied fields will change in a full cycle. This paper assumes when the ac current or field starts to change in the other direction, a new penetrated region will begin to penetrate from the superconductor surface. If we assume Jc is constant in the critical region, this paper demonstrates that the Claassen formula (7) can be used to calculate the exact ac losses. If Jc depends on local Bz, we can use Eq. (9) to quickly predict the ac losses. This approach does not need to calculate a complete ac cycle. This saves considerably computation time while gives a result which is in close agreement with that calculated from a complete ac cycle. The calculation method can be applied for calculating a superconducting pancake coil if the coil radius is much larger than the tape width.

  16. AC loss characteristics of simulated CIC-type conductors having plastic conduit

    NASA Astrophysics Data System (ADS)

    Kojo, Y.; Sekine, N.; Tada, S.; Yamaguchi, Y.; Obama, J.; Takao, T.; Miyagi, D.; Yamanaka, A.

    2003-10-01

    When alternating current superconducting coils having cable-in-conduit conductors are fabricated, non-metallic conduit materials are necessary to avoid eddy current losses in the conduits. Using two kinds of non-metallic tapes made of glass fiber reinforced plastics (GFRPs) and Dyneema fiber reinforced plastics (DFRPs), we made the conductors with the GFRP conduits and DFRP conduits, and experimentally studied the total losses of the conductors. The measured results showed that the total loss of the conductor with the GFRP conduit was smaller than that with the DFRP conduit at the same value of the void ratio, the transport current, the external magnetic field, and so on. When the void ratios become high, the superconducting bundle cable can easily move in the conduit. Hence the measured total losses increased with the void ratios of the conductors.

  17. How filaments can reduce AC losses in HTS coated conductors: a review

    NASA Astrophysics Data System (ADS)

    Grilli, Francesco; Kario, Anna

    2016-08-01

    Second-generation high-temperature superconductor (HTS) tapes, known also as coated conductors, are very promising tapes for HTS applications, in virtue of their extremely high critical current density, in-field behavior, and mechanical strength. Yet, the extremely large (typically in the range 1000–10 000) width-to-thickness ratio of the superconducting material makes them prone to high power dissipation in the presence of time-varying magnetic fields perpendicular to their flat face—a condition frequently met in several applications. Since the dissipation is directly proportional to the square of the superconductor's width, an obvious way of reducing it is by striating the superconductor into narrow filaments (stripes): in that case, provided that the filaments are electromagnetically uncoupled, the losses are reduced by a factor equal to the number of filaments. In the past two decades, many researchers from groups around the world have tried to apply this idea to practical conductors using different techniques. The aim of this paper is to provide a review of such efforts, focusing on the different approaches to make filamentized conductors, on the effectiveness of the AC loss reduction, and on the applicability of those techniques to long lengths.

  18. Accelerated life ac conductivity measurements of CRT oxide cathodes

    NASA Astrophysics Data System (ADS)

    Hashim, A. A.; Barratt, D. S.; Hassan, A. K.; Nabok, A.

    2006-07-01

    The ac conductivity measurements have been carried out for the activated Ba/SrO cathode with additional 5% Ni powder for every 100 h acceleration life time at the temperature around 1125 K. The ac conductivity was studied as a function of temperature in the range 300-1200 K after conversion and activation of the cathode at 1200 K for 1 h in two cathodes face to face closed configuration. The experimental results prove that the hopping conductivity dominate in the temperature range 625-770 K through the traps of the WO 3 associate with activation energy Ea = 0.87 eV, whereas from 500-625 K it is most likely to be through the traps of the Al 2O 3 with activation energy of Ea = 1.05 eV. The hopping conductivity at the low temperature range 300-500 K is based on Ni powder link with some Ba contaminants in the oxide layer stricture which indicates very low activation energy Ea = 0.06 eV.

  19. AC losses in a finite Z stack using an anisotropic homogeneous-medium approximation

    NASA Astrophysics Data System (ADS)

    Clem, John R.; Claassen, J. H.; Mawatari, Yasunori

    2007-12-01

    A finite stack of thin superconducting tapes, all carrying a fixed current I, can be approximated by an anisotropic superconducting bar with critical current density Jc = Ic/2aD, where Ic is the critical current of each tape, 2a is the tape width, and D is the tape-to-tape periodicity. The current density J must obey the constraint \\int J\\, \\mathrm {d}x=I/D , where the tapes lie parallel to the x axis and are stacked along the z axis. We suppose that Jc is independent of field (Bean approximation) and look for a solution to the critical state for arbitrary height 2b of the stack. For c<|x|losses depend only weakly on how c is chosen. We argue that for small D/a the anisotropic homogeneous-medium approximation gives a reasonably accurate estimate of the ac losses in a finite Z stack. The results for a Z stack can be used to calculate the transport losses in a pancake coil wound with superconducting tape.

  20. Absorption and Attenuation Coefficients Using the WET Labs ac-s in the Mid-Atlantic Bight: Field Measurements and Data Analysis

    NASA Technical Reports Server (NTRS)

    Ohi, Nobuaki; Makinen, Carla P.; Mitchell, Richard; Moisan, Tiffany A.

    2008-01-01

    Ocean color algorithms are based on the parameterization of apparent optical properties as a function of inherent optical properties. WET Labs underwater absorption and attenuation meters (ac-9 and ac-s) measure both the spectral beam attenuation [c (lambda)] and absorption coefficient [a (lambda)]. The ac-s reports in a continuous range of 390-750 nm with a band pass of 4 nm, totaling approximately 83 distinct wavelengths, while the ac-9 reports at 9 wavelengths. We performed the ac-s field measurements at nine stations in the Mid-Atlantic Bight from water calibrations to data analysis. Onboard the ship, the ac-s was calibrated daily using Milli Q-water. Corrections for the in situ temperature and salinity effects on optical properties of water were applied. Corrections for incomplete recovery of the scattered light in the ac-s absorption tube were performed. The fine scale of spectral and vertical distributions of c (lambda) and a (lambda) were described from the ac-s. The significant relationships between a (674) and that of spectrophotometric analysis and chlorophyll a concentration of discrete water samples were observed.

  1. Aerial measurement of heat loss: Phase II

    SciTech Connect

    Not Available

    1982-07-01

    The purpose of the program described was to develop techniques to reduce or eliminate some of the variables associated with thermogram analysis in order to provide more objective interpretation of the data collected with greater potential for accuracy. A procedure is given for measuring temperature which accounts for atmospheric, background, and differential emissivity effects. The residual error was found to be 1.0/sup 0/C. A technique was then identified and developed for determining heat loss lovels from roof top surface temperature data. A thermal integrity factor was defined as a function of insulation level and thermostat setting. Comparing these thermal integrity factors with aerial thermography data indicates that aerial thermography can be used to objectively and confidently define heat loss levels from building roofs. (LEW)

  2. Angular Dependence of Transport AC Losses in Superconducting Wire with Position-Dependent Critical Current Density in a DC Magnetic Field

    NASA Astrophysics Data System (ADS)

    Su, Xing-liang; Xiong, Li-ting; Gao, Yuan-wen; Zhou, You-he

    2013-07-01

    Transport AC losses play a very important role in high temperature superconductors (HTSs), which usually carry AC transport current under applied magnetic field in typical application-like conditions. In this paper, we propose the analytical formula for transport AC losses in HTS wire by considering critical current density of both inhomogeneous and anisotropic field dependent. The angular dependence of critical current density is described by effective mass theory, and the HTS wire has inhomogeneous distribution cross-section of critical current density. We calculate the angular dependence of normalized AC losses under different DC applied magnetic fields. The numerical results of this formula agree well with the experiment data and are better than the results of Norris formula. This analytical formula can explain the deviation of experimental transport current losses from the Norris formula and apply to calculate transport AC losses in realistic practical condition.

  3. AC Circuit Measurements with a Differential Hall Element Magnetometer

    NASA Astrophysics Data System (ADS)

    Calkins, Matthew W.; Nicks, B. Scott; Quintero, Pedro A.; Meisel, Mark W.

    2013-03-01

    As the biomedical field grows, there is an increasing need to quickly and efficiently characterize more samples at room temperature. An automated magnetometer was commissioned to do these room temperature magnetic characterizations. This magnetometer, which is inspired by a Differential Hall Element Magnetometer,[2] uses two commercially available Hall elements wired in series. One Hall element measures the external magnetic field of a 9 T superconducting magnet and the other measures the same external field plus the field due to the magnetization of the sample that sits on top of the Hall element. The difference between these two Hall elements is taken while a linear stepper motor sweeps through the external magnetic field. The linear motor and data acquisition are controlled by a LabVIEW program. Recently, the system was outfitted for AC circuit measurements and these data will be compared to DC circuit data. In addition, the lowest signal to noise ratio will be found in order to deduce the smallest amount of sample needed to register an accurate coercive field. Supported by the NSF via NHMFL REU (DMR-0654118), a single investigator grant (DMR-1202033 to MWM) and by the UF Undergraduate Scholars Program.

  4. Measurement of AC Induced Flow using Mico PIV

    NASA Astrophysics Data System (ADS)

    Wang, Dazhi; Meinhart, Carl; Sigurdson, Marin

    2002-11-01

    The fluid motion in a wedge-shaped device subject to an AC electric field is measured using Micron-Resolution Particle Image Velocimetry (micro-PIV). The fluorescent polystyrene spherical particles are used as flow tracers. In the non-uniform electric field, the particles in the suspension experience dielectrophoretic forces, which cause difference of velocities between the particles and the fluid. In order to eliminate the velocity difference, two different size particles are used for the micro-PIV measurements to determine the fluid velocity field. A two-color PIV technique is used to determine uniquely the fluid velocity field. The wedge-shaped channel is 100-micron wide at the apex, and fabricated from a 550-micron thick silicon wafer. A voltage of 15Vrms at 100 kHz is applied to the electrodes. The particle volume fraction is set below 0.1% so that the effect of the particles on the fluid can be negligible. Fifty successive images are taken to record particle images and analyzed to estimate the particle velocity fields. The velocity fields of the two different size particles are then used to uniquely determine the underlying fluid velocity. The measured fluid flow is a saddle-point flow, which could be used for precision mixing and transport in microscale devices.

  5. Microfabricated Thin Film Impedance Sensor & AC Impedance Measurements

    PubMed Central

    Yu, Jinsong; Liu, Chung-Chiun

    2010-01-01

    Thin film microfabrication technique was employed to fabricate a platinum based parallel-electrode structured impedance sensor. Electrochemical impedance spectroscopy (EIS) and equivalent circuit analysis of the small amplitude (±5 mV) AC impedance measurements (frequency range: 1 MHz to 0.1 Hz) at ambient temperature were carried out. Testing media include 0.001 M, 0.01 M, 0.1 M NaCl and KCl solutions, and alumina (∼3 μm) and sand (∼300 μm) particulate layers saturated with NaCl solutions with the thicknesses ranging from 0.6 mm to 8 mm in a testing cell, and the results were used to assess the effect of the thickness of the particulate layer on the conductivity of the testing solution. The calculated resistances were approximately around 20 MΩ, 4 MΩ, and 0.5 MΩ for 0.001 M, 0.01 M, and 0.1 M NaCl solutions, respectively. The presence of the sand particulates increased the impedance dramatically (6 times and 3 times for 0.001 M and 0.1 M NaCl solutions, respectively). A cell constant methodology was also developed to assess the measurement of the bulk conductivity of the electrolyte solution. The cell constant ranged from 1.2 to 0.8 and it decreased with the increase of the solution thickness. PMID:22219690

  6. Numerical models for ac loss calculation in large-scale applications of HTS coated conductors

    NASA Astrophysics Data System (ADS)

    Quéval, Loïc; Zermeño, Víctor M. R.; Grilli, Francesco

    2016-02-01

    Numerical models are powerful tools to predict the electromagnetic behavior of superconductors. In recent years, a variety of models have been successfully developed to simulate high-temperature-superconducting (HTS) coated conductor tapes. While the models work well for the simulation of individual tapes or relatively small assemblies, their direct applicability to devices involving hundreds or thousands of tapes, e.g., coils used in electrical machines, is questionable. Indeed, the simulation time and memory requirement can quickly become prohibitive. In this paper, we develop and compare two different models for simulating realistic HTS devices composed of a large number of tapes: (1) the homogenized model simulates the coil using an equivalent anisotropic homogeneous bulk with specifically developed current constraints to account for the fact that each turn carries the same current; (2) the multi-scale model parallelizes and reduces the computational problem by simulating only several individual tapes at significant positions of the coil’s cross-section using appropriate boundary conditions to account for the field generated by the neighboring turns. Both methods are used to simulate a coil made of 2000 tapes, and compared against the widely used H-formulation finite-element model that includes all the tapes. Both approaches allow faster simulations of large number of HTS tapes by 1-3 orders of magnitudes, while maintaining good accuracy of the results. Both models can therefore be used to design and optimize large-scale HTS devices. This study provides key advancement with respect to previous versions of both models. The homogenized model is extended from simple stacks to large arrays of tapes. For the multi-scale model, the importance of the choice of the current distribution used to generate the background field is underlined; the error in ac loss estimation resulting from the most obvious choice of starting from a uniform current distribution is revealed.

  7. The magnetisation profiles and ac magnetisation losses in a single layer YBCO thin film caused by travelling magnetic field waves

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Coombs, Timothy

    2015-05-01

    This paper studies the magnetisation and ac magnetisation losses caused by a travelling magnetic wave on a single-layer YBCO thin film. This work provides thorough investigations on how the critical magnetic field gradient has been changed by the application of a travelling wave. Several conditions were studied such as zero-field cooling (ZFC), field cooling (FC) and a delta-shaped trapped field. It was found that the travelling wave tends to attenuate the existing critical magnetic field gradients in all these conditions. This interesting magnetic behaviour can be well predicted by the finite element (FEM) software with the E-J power law and Maxwell’s equations. The numerical simulations show that the existing critical current density has been compromised after applying the travelling wave. The magnetisation profile caused by the travelling wave is very different from the standing wave, while the magnetisation based on the standing wave can be interpreted by the Bean model and constant current density assumption. Based on the numerical method, which has reliability that has been solidly proven in the study, we have extended the study to the ac magnetisation losses. Comparisons were made between the travelling wave and the standing wave for this specific YBCO sample. It was found that by applying the magnetic wave of the same amplitude, the ac magnetisation loss caused by the travelling wave is about 1/3 of that caused by the standing wave. These results are helpful in understanding the general magnetism problems and ac magnetisation loss in the travelling magnetic wave conditions such as inside a high temperature superconducting (HTS) rotating machine, etc.

  8. Small Aircraft RF Interference Path Loss Measurements

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Szatkowski, George N.; Mielnik, John J.; Salud, Maria Theresa P.

    2007-01-01

    Interference to aircraft radio receivers is an increasing concern as more portable electronic devices are allowed onboard. Interference signals are attenuated as they propagate from inside the cabin to aircraft radio antennas mounted on the outside of the aircraft. The attenuation level is referred to as the interference path loss (IPL) value. Significant published IPL data exists for transport and regional category airplanes. This report fills a void by providing data for small business/corporate and general aviation aircraft. In this effort, IPL measurements are performed on ten small aircraft of different designs and manufacturers. Multiple radio systems are addressed. Along with the typical worst-case coupling values, statistical distributions are also reported that could lead to more meaningful interference risk assessment.

  9. Harmonic analysis of AC magnetostriction measurements under non-sinusoidal excitation

    SciTech Connect

    Mogi, Hisashi; Yabumoto, Masao; Mizokami, Masato; Okazaki Yasuo

    1996-09-01

    A new system for analyzing ac magnetostriction of electrical steel sheets has been developed. This system has the following advantages: (a) AC magnetostriction waveforms can be precisely measured up to 4 kHz, and analyzed to harmonic components; (b) non-sinusoidal flux density can be excited to simulate the distorted waveform in an actual transformer core.

  10. Microwave Absorption and Low-Frequency AC Losses in 1-2-3 Cuprate Superconductors

    NASA Astrophysics Data System (ADS)

    Huang, Ming Xun

    We have studied various aspects of microwave absorption in cuprates of the prototype REBa_2Cu _3O_{rm x} (6 < x < 7), where RE stands for Y or a rare earth ion. The first series of experiments concern the discovery and subsequent elucidation of a huge increase in zero field microwave absorption, at temperatures below 20 K, in micron size powder samples of ErBa_2Cu _3O_{rm x}. The field dependence of the microwave absorption was used to show that this abnormal zero field signal is a part of a broad and highly distorted electron spin resonance (ESR) spectrum. Spectra at different frequencies were analyzed using the "weak exchange, strong dipole field" Kubo-Toyabe model for the first time and we conclude that there is a large (~1 kOe) fluctuating local dipolar field at the Er site coming from the other Er^{3+} magnetic moments. For better understanding, experiments were done on ESR in powders of Er_{rm x}Y _{rm 1-z}Ba_2 Cu_3O_6 (0.02 < z < 1). For z < 0.4, another partially resolved line appeared at low fields. These spectra cannot be described as a powder pattern due to a single line with an anisotropic g-value. Rather they appear to be the sum of two Kubo -Toyabe lines. Most likely these lines are resonances coming from two closely spaced (~1K) low lying doublets. Crystal field calculations indicate that the distortion away from cubic symmetry implied by our results is much smaller than that required to describe the results of neutron scattering measurements. Another series of experiments were done to measure the increase in the microwave absorption in thin films of YBa_2Cu_3O _7 due to the application of a dc magnetic field (B) between 0.45 and 1.4 Tesla at 0.8 < (T/Tc) < 1. The data are very well represented by conventional models of fluxon dynamics. We have also measured the real (chi _1) and imaginary (chi_2 ) parts of the low frequency (<150 Hz) complex ac susceptibility. It was found that the data can be understood by using the Bean model.

  11. Loss tangent measurements on unirradiated alumina

    SciTech Connect

    Zinkle, S.J.; Goulding, R.H.

    1996-04-01

    Unirradiated room temperature loss tangent for sapphire and several commercial grades of polycrystalline alumina are complied for frequencies between 10{sup 5} and 4x10{sup 11} Hz. Sapphire exhibits significantly lower values for the loss tangent at frequencies up to 10{sup 11} Hz. The loss tangents of 3 different grades of Wesgo alumina (AL300, AL995, AL998) and 2 different grades of Coors alumina (AD94, AD995) have typical values near {approx}10{sup -4} at a frequency of 10{sup 8} Hz. On the other hand, the loss tangent of Vitox alumina exhibits a large loss peak tan d{approx} 5x10{sup -3} at this frequency.

  12. Ripple field losses in direct current biased superconductors: Simulations and comparison with measurements

    NASA Astrophysics Data System (ADS)

    Lahtinen, Valtteri; Pardo, Enric; Šouc, Ján; Solovyov, Mykola; Stenvall, Antti

    2014-03-01

    In several superconducting applications, as, for example, in some supercondcuting generators, motors, and power transmission cables, the superconductor experiences a changing magnetic field in a DC background. Simulating the losses caused by this AC ripple field is an important task from the application design point of view. In this work, we compare two formulations, the H-formulation and the minimum magnetic energy variation-formulation, based on the eddy current model (ECM) and the critical state model (CSM), respectively, for simulating ripple field losses in a DC biased coated conductor tape. Furthermore, we compare our simulation results with measurements. We investigate the frequency-dependence of the hysteresis loss predictions of the power law based ECM and verify by measurements, that in DC use, ECM clearly over-estimates the homogenization of the current density profile in the coated conductor tape: the relaxation of the local current density is not nearly as prominent in the measurement as it is in the simulation. Hence, we suggest that the power law resistivity, used as the local relation between the electric field intensity E and current density J in ECM, is not an intrinsic property of high-temperature superconductors. The difference between the models manifests itself as discrepancies in ripple field loss simulations in very low AC fields with significant DC fields or currents involved. The results also show, however, that for many practical situations, CSM and ECM are both eligible models for ripple field loss simulations.

  13. Ripple current loss measurement with DC bias condition for high temperature superconducting power cable using calorimetry method

    NASA Astrophysics Data System (ADS)

    Kim, D. W.; Kim, J. G.; Kim, A. R.; Park, M.; Yu, I. K.; Sim, K. D.; Kim, S. H.; Lee, S. J.; Cho, J. W.; Won, Y. J.

    2010-11-01

    The authors calculated the loss of the High Temperature Superconducting (HTS) model cable using Norris ellipse formula, and measured the loss of the model cable experimentally. Two kinds of measuring method are used. One is the electrical method, and the other is the calorimetric method. The electrical method can be used only in AC condition. But the calorimetric method can be used in both AC and DC bias conditions. In order to propose an effective measuring approach for Ripple Dependent Loss (RDL) under DC bias condition using the calorimetric method, Bismuth Strontium Calcium Copper Oxide (BSCCO) wires were used for the HTS model cable, and the SUS tapes were used as a heating tape to make the same pattern of the temperature profiles as in the electrical method without the transport current. The temperature-loss relations were obtained by the electrical method, and then applied to the calorimetric method by which the RDL under DC bias condition was well estimated.

  14. Examination of Humidity Effects on Measured Thickness and Interfacial Phenomena of Exfoliated Graphene on SiO2 via AC-AFM

    NASA Astrophysics Data System (ADS)

    Jinkins, Katherine; Camacho, Jorge; Farina, Lee; Wu, Yan

    2015-03-01

    Tapping (AC) mode Atomic Force Microscopy (AFM) is commonly used to determine the thickness of graphene samples. However, AFM measurements have been shown to be sensitive to environmental conditions such as adsorbed water, in turn dependent on relative humidity (RH). In the present study, AC-AFM is used to measure the thickness and loss tangent of exfoliated graphene on silicon dioxide (SiO2) as RH is increased from 10% to 80%. We show that the measured thickness of graphene is dependent on RH. Loss tangent is an AFM imaging technique that interprets the phase information as a relationship between the stored and dissipated energy in the tip-sample interaction. This study demonstrates the loss tangent of the graphene and oxide regions are both affected by humidity, with generally higher loss tangent for graphene than SiO2. As RH increases, we observe the loss tangent of both materials approaches the same value. We hypothesize that there is a layer of water trapped between the graphene and SiO2 substrate to explain this observation. Using this interpretation, the loss tangent images also indicate movement and change in this trapped water layer as RH increases, which impacts the measured thickness of graphene using AC-AFM.

  15. Construction of Tunnel Diode Oscillator for AC Impedance Measurement

    NASA Astrophysics Data System (ADS)

    Shin, J. H.; Kim, E.

    2014-03-01

    We construct a tunnel diode oscillator (TDO) to study electromagnetic response of a superconducting thin film. Highly sensitive tunnel diode oscillators allow us to detect extremely small changes in electromagnetic properties such as dielectric constant, ac magnetic susceptibility and magnetoresistance. A tunnel diode oscillator is a self-resonant oscillator of which resonance frequency is primarily determined by capacitance and inductance of a resonator. Amplitude of the signal depends on the quality factor of the resonator. The change in the impedance of the sample electromagnetic coupled to one of inductors in the resonator alters impedance of the inductor, and leads to the shift in the resonance frequency and the change of the amplitude.

  16. MEASURED AND CALCULATED LOSSES IN A MODEL DIPOLE FOR GSI'S HEAVY ION SYNCHROTRON.

    SciTech Connect

    WANDERER,P.; ANERELLA,M.; GANETIS,G.; GHOSH,A.K.; JOSHI,P.; MARONE,A.; MURATORE,J.; ET AL.

    2003-06-15

    The new heavy ion synchrotron facility proposed by GSI will have two superconducting magnet rings in the same tunnel, with rigidities of 300T{center_dot}m and 10OT{center_dot}m. Fast ramp times are needed. These can cause problems of ac loss and field distortion in the magnets. For the high energy ring, a lm model dipole magnet has been built, based on the RHIC dipole design. This magnet was tested under boiling liquid helium in a vertical dewar. The quench current showed very little dependence on ramp rate. The ac losses, measured by an electrical method, were fitted to straight line plots of loss/cycle versus ramp rate, thereby separating the eddy current and hysteresis components. These results were compared with calculated values, using parameters which had previously been measured on short samples of cable. Reasonably good agreement between theory and experiment was found, although the measured hysteresis loss is higher than expected in ramps to the highest field levels.

  17. Dielectric Loss Measurements on Raw Materials.

    ERIC Educational Resources Information Center

    Mwanje, J.

    1980-01-01

    Describes an experiment used to study dielectric properties of materials. Values of the dielectric loss tangent can be determined at low frequencies from Lissajous figures formed on an oscilloscope. Some mineral rock specimens show Debye-type relaxation peaks at frequencies in the region of 1 to 500 Hz. (Author/DS)

  18. Numerical analysis of ac loss in bifilar stacks and coils of ion beam assisted deposition YBCO coated conductors

    SciTech Connect

    Nguyen, Doan N.; Ashworth, Stephen P.; Willis, Jeffrey O.

    2009-03-15

    In this paper we present a finite element model using the commercial COMSOL software package for calculating the ac loss in bifilar stacks of high temperature superconducting tape. In the model, the current-voltage relationship characterizing the superconducting properties is assumed to follow a power law. The calculations were performed for infinite bifilar stacks with different values of layer-to-layer separation D. With appropriate settings for the boundary conditions, the numerical results agree well with the analytical data obtained from a recently proposed model [J. R. Clem, Phys. Rev. B 77, 134506 (2008)]. The numerical approach was also used to investigate the end effects in a bifilar stack to answer the following question: how many layers away from the end of a stack are required before the environment of a given layer is identical to that in an infinite stack? We find that the answer to this question depends strongly on the value of D. Based on this study, a model for calculating the ac loss in bifilar noninductively wound coils with a finite number of turns is proposed.

  19. AC Loss Calculation of REBCO Cables by the Combination of Electric Circuit Model and 2D Finite Element Method

    NASA Astrophysics Data System (ADS)

    Noji, H.

    This study investigates the losses in a two conducting-layer REBCO cable fabricated by researchers at Furukawa Electric Co. Ltd. The losses were calculated using a combination of my electric circuit (EC) model with a two-dimensional finite element method (2D FEM). The helical pitches of the tapes in each layer, P1 and P2, were adjusted to equalize the current in both cable layers, although the loss calculation assumed infinite helical pitches and the same current in each layer at first. The results showed that the losses depended on the relative tape-position angle between the layers (θ/θ'), because the vertical field between adjacent tapes in the same layer varied with θ/θ'. When simulating the real cable, the helical pitches were adjusted and the layer currents were calculated by the EC model. These currents were input to the 2D FEM to compute the losses. The losses changed along the cable length because the difference between P1 and P2 altered the θ/θ' along this direction. The average angle-dependent and position-dependent losses were equal and closely approximated the measured losses. As an example to reduce the loss in this cable, the angle and the helical pitches were fixed at θ/θ' = 0.5 and P1 = P2 = 100 mm (S-direction). The calculation with these conditions indicated that the loss is about one order of magnitude lower than the measurement.

  20. Measurements of Beam Ion Loss from the Compact Helical System

    SciTech Connect

    D. S. Darrow, M. Isobe, Takashi Kondo, M. Sasao, and the CHS Group National Institute for Fusion Science, Toki, Gifu, Japan

    2010-02-03

    Beam ion loss from the Compact Helical System (CHS) has been measured with a scintillator-type probe. The total loss to the probe, and the pitch angle and gyroradius distributions of that loss, have been measured as various plasma parameters were scanned. Three classes of beam ion loss were observed at the probe position: passing ions with pitch angles within 10o of those of transition orbits, ions on transition orbits, and ions on trapped orbits, typically 15o or more from transition orbits. Some orbit calculations in this geometry have been performed in order to understand the characteristics of the loss. Simulation of the detector signal based upon the following of orbits from realistic beam deposition profiles is not able to reproduce the pitch angle distribution of the losses measured. Consequently it is inferred that internal plasma processes, whether magnetohydrodynamic modes, radial electric fields, or plasma turbulence, move previously confined beam ions to transition orbits, resulting in their loss.

  1. The Wechsler ACS Social Perception Subtest: A Preliminary Comparison with Other Measures of Social Cognition

    ERIC Educational Resources Information Center

    Kandalaft, Michelle R.; Didehbani, Nyaz; Cullum, C. Munro; Krawczyk, Daniel C.; Allen, Tandra T.; Tamminga, Carol A.; Chapman, Sandra B.

    2012-01-01

    Relative to other cognitive areas, there are few clinical measures currently available to assess social perception. A new standardized measure, the Wechsler Advanced Clinical Solutions (ACS) Social Perception subtest, addresses some limitations of existing measures; however, little is known about this new test. The first goal of this investigation…

  2. ac driving amplitude dependent systematic error in scanning Kelvin probe microscope measurements: Detection and correction

    SciTech Connect

    Wu Yan; Shannon, Mark A.

    2006-04-15

    The dependence of the contact potential difference (CPD) reading on the ac driving amplitude in scanning Kelvin probe microscope (SKPM) hinders researchers from quantifying true material properties. We show theoretically and demonstrate experimentally that an ac driving amplitude dependence in the SKPM measurement can come from a systematic error, and it is common for all tip sample systems as long as there is a nonzero tracking error in the feedback control loop of the instrument. We further propose a methodology to detect and to correct the ac driving amplitude dependent systematic error in SKPM measurements. The true contact potential difference can be found by applying a linear regression to the measured CPD versus one over ac driving amplitude data. Two scenarios are studied: (a) when the surface being scanned by SKPM is not semiconducting and there is an ac driving amplitude dependent systematic error; (b) when a semiconductor surface is probed and asymmetric band bending occurs when the systematic error is present. Experiments are conducted using a commercial SKPM and CPD measurement results of two systems: platinum-iridium/gap/gold and platinum-iridium/gap/thermal oxide/silicon are discussed.

  3. Ultrasonic airborne insertion loss measurements at normal incidence (L).

    PubMed

    Farley, Jayrin; Anderson, Brian E

    2010-12-01

    Transmission loss and insertion loss measurements of building materials at audible frequencies are commonly made using plane wave tubes or as a panel between reverberant rooms. These measurements provide information for noise isolation control in architectural acoustics and in product development. Airborne ultrasonic sound transmission through common building materials has not been fully explored. Technologies and products that utilize ultrasonic frequencies are becoming increasingly more common, hence the need to conduct such measurements. This letter presents preliminary measurements of the ultrasonic insertion loss levels for common building materials over a frequency range of 28-90 kHz using continuous-wave excitation. PMID:21218864

  4. Development of Low-Frequency AC Voltage Measurement System Using Single-Junction Thermal Converter

    NASA Astrophysics Data System (ADS)

    Amagai, Yasutaka; Nakamura, Yasuhiro

    Accurate measurement of low-frequency AC voltage using a digital multimeter at frequencies of 4-200Hz is a challenge in the mechanical engineering industry. At the National Metrology Institute of Japan, we developed a low-frequency AC voltage measurement system for calibrating digital multimeters operating at frequencies down to 1 Hz. The system uses a single-junction thermal converter and employs a theoretical model and a three-parameter sine wave fitting algorithm based on the least-square (LS) method. We calibrated the AC voltage down to 1Hz using our measurement system and reduced the measurement time compared with that using thin-film thermal converters. Our measurement results are verified by comparison with those of a digital sampling method using a high-resolution analog-to-digital converter; our data are in agreement to within a few parts in 105. Our proposed method enables us to measure AC voltage with an uncertainty of 25 μV/V (k = 1) at frequencies down to 4 Hz and a voltage of 10 V.

  5. Measurements of the Seebeck coefficient of thermoelectric materials by an ac method

    SciTech Connect

    Goto, T.; Li, J.H.; Hirai, T.; Maeda, Y.; Kato, R.; Maesono, A.

    1997-03-01

    An ac method for measurement of the Seebeck coefficient was developed. Specimens were heated periodically at frequencies in the range 0.2--10 Hz using a semiconductor laser. The small temperature increase and the resultant thermoelectric power were measured with a Pt-Pt 13% Rh thermocouple (25 {micro}m in diameter) through a lock-in amplifier. The Seebeck coefficient of a Pt{sub 90}Rh{sub 10} foil measured by the ac method was in agreement with that obtained from the standard table. The optimum frequency and specimen thickness for the ac method were 0.2 Hz and 0.1--0.2 mm, respectively. The Seebeck coefficients of silicon single crystal and several thermoelectric semiconductors (Si{sub 80}Ge{sub 20}, PbTc, FeSi{sub 2}, SiB{sub 14}) measured by the ac method agreed with those measured by a conventional dc method in the temperature range between room temperature and 1200 K. The time needed for each measurement was less than a few tens of minutes, significantly shorter than that for a conventional dc method.

  6. Fiber - Optic Devices as Temperature Sensors for Temperature Measurements in AC Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Rablau, Corneliu; Lafrance, Joseph; Sala, Anca

    2007-10-01

    We report on the investigation of several fiber-optic devices as potential sensors for temperature measurements in AC magnetic fields. Common temperature sensors, such as thermocouples, thermistors or diodes, will create random and/or systematic errors when placed in a magnetic field. A DC magnetic field is susceptible to create a systematic offset to the measurement, while in an AC magnetic field of variable frequency random errors which cannot be corrected for can also be introduced. Fiber-Bragg-gratings and thin film filters have an inherent temperature dependence. Detrimental for their primary applications, the same dependence allows one to use such devices as temperature sensors. In an AC magnetic field, they present the advantage of being immune to electromagnetic interference. Moreover, for fiber-Bragg-gratings, the shape factor and small mass of the bare-fiber device make it convenient for temperature measurements on small samples. We studied several thin-film filters and fiber-Bragg-gratings and compared their temperature measurement capabilities in AC magnetic fields of 0 to 150 Gauss, 0 to 20 KHz to the results provided by off-the-shelf thermocouples and thermistor-based temperature measurement systems.

  7. AC conductivity and dielectric measurements of metal-free phthalocyanine thin films dispersed in polycarbonate

    NASA Astrophysics Data System (ADS)

    Riad, A. S.; Korayem, M. T.; Abdel-Malik, T. G.

    1999-10-01

    The dielectric constant and the dielectric loss of thin films of metal-free phthalocyanine dispersed in polycarbonate using ohmic gold electrodes are investigated in the frequency range 20-10 5 Hz and within the temperature range 300-388 K. The frequency dependence of the impedance spectra plotted in the complex plane shows semicircles. The Cole-Cole diagrams have been used to determine the molecular relaxation time, τ, The temperature dependence of τ is expressed by thermally activated process. The AC conductivity σ AC (ω) is found to vary as ωs with the index s⩽1, indicating a dominant hopping process at low temperatures. From the temperature dependence of AC conductivity, free carrier conduction with mean activation energy of 0.33 eV is observed at higher temperatures. Capacitance and loss tangent are found to decrease with increasing frequency and increase with increasing temperature. Such characteristics are found to be in good qualitative agreement with existing equivalent circuit model assuming ohmic contacts.

  8. New ac microammeter for leakage current measurement of biomedical equipment

    NASA Astrophysics Data System (ADS)

    Branca, F. P.; Del Prete, Z.; Marinozzi, F.

    1993-11-01

    A new inexpensive current probe for on-line leakage current measurement of biomedical devices in hospital environment is described. The prototype is designed to detect and measure leakage currents on the ground wire of the device's power cord so that its integrity can be monitored in real time. Realized with a sensing coil specially matched to a low-noise op amp, this probe adds only negligible impedance on the monitored ground lines. From this preliminary study about the device's metrological performances, a sensitivity of 10 nArms for a current range 1-500 μArms has emerged, together with a mean linearity error of 0.03% and a frequency response flat within 1% of gain from 50 to 2000 Hz.

  9. AC losses and heat removal in three-dimensional winding pack of Samsung superconducting test facility under pulsed magnetic field operation

    NASA Astrophysics Data System (ADS)

    Wang, Qiuliang; Seong Yoon, Cheon; Baang, Sungkeun; Kim, Myungkyu; Park, Hyunki; Kim, Yongjin; Lee, Sangil; Kim, Keeman

    2001-04-01

    The Samsung superconducting test facility (SSTF) will be operated under the highly pulsed field to simulate the operating conditions of KSTAR. An analysis has been performed to study the transient heat removal characteristics and temperature margin for the main, blip and compensating coils in the SSTF. This method is based on a quasi-three-dimensional model, which the thermal coupling of turn-to-turn, pancake-to-pancake and channel-to-channel is taken into account, to simulate the conductor temperature rise and the thermal expansion of supercritical helium due to the high AC losses under the pulsed field. The local AC losses, which include coupling loss, eddy current loss and hysteresis loss in the cable-in-conduit conductor, are estimated. The temperature margin, mass flow rate, distribution of AC losses are studied under the given operating scenario. The mass flow reduction and peak temperature rise depending on the inlet pressure and inlet position of CICC are studied. It is shown that the initial mass flow rate remarkably influences on the peak temperature of superconducting strands. The large mass flow rate can reduce the temperature rise when the inlet of helium is located at the high field region. By contrast, because of heat induced flow to improve the cooling condition of the superconducting strands, the small initial mass flow rate results in the low peak temperature in strands when the inlet of helium is located at the low field region.

  10. Monitoring colloidal stability of polymer-coated magnetic nanoparticles using AC susceptibility measurements.

    PubMed

    Herrera, Adriana P; Barrera, Carola; Zayas, Yashira; Rinaldi, Carlos

    2010-02-15

    The application of the response of magnetic nanoparticles to oscillating magnetic fields to probe transitions in colloidal state and structure of polymer-coated nanoparticles is demonstrated. Cobalt ferrite nanoparticles with narrow size distribution were prepared and shown to respond to oscillating magnetic fields through a Brownian relaxation mechanism, which is dependent on the mechanical coupling between the particle dipoles and the surrounding matrix. These nanoparticles were coated with covalently-attached poly(N-isopropylacrylamide) (pNIPAM) or poly(N-isopropylmethacrylamide) (pNIPMAM) through free radical polymerization. The temperature induced transitions of colloidal suspensions of these nanoparticles were studied through a combination of differential scanning calorimetry (DSC), dynamic light scattering (DLS), and AC susceptibility measurements. In the pNIPAM coated nanoparticles excellent agreement was found for a transition temperature of approximately 30 degrees C by all three methods, although the AC susceptibility measurements indicated aggregation which was not evident from the DLS results. Small-angle neutron scattering (SANS) results obtained for pNIPAM coated nanoparticles confirmed that aggregation indeed occurs above the lower critical transition temperature of pNIPAM. For the pNIPMAM coated nanoparticles DLS and AC susceptibility measurements indicated aggregation at a temperature of approximately 33-35 degrees C, much lower than the transition temperature peak at 40 degrees C observed by DSC. However, the transition observed by DSC is very broad, hence it is possible that aggregation begins to occur at temperatures lower than the peak, as indicated by the AC susceptibility and DLS results. These experiments and observations demonstrate the possibility of using AC susceptibility measurements to probe transitions in colloidal suspensions induced by external stimuli. Because magnetic measurements do not require optical transparency, these

  11. Superconducting-magnetic heterostructures: a method of decreasing AC losses and improving critical current density in multifilamentary conductors.

    PubMed

    Glowacki, B A; Majoros, M

    2009-06-24

    Magnetic materials can help to improve the performance of practical superconductors on the macroscale/microscale as magnetic diverters and also on the nanoscale as effective pinning centres. It has been established by numerical modelling that magnetic shielding of the filaments reduces AC losses in self-field conditions due to decoupling of the filaments and, at the same time, it increases the critical current of the composite. This effect is especially beneficial for coated conductors, in which the anisotropic properties of the superconductor are amplified by the conductor architecture. However, ferromagnetic coatings are often chemically incompatible with YBa(2)Cu(3)O(7) and (Pb,Bi)(2)Sr(2)Ca(2)Cu(3)O(9) conductors, and buffer layers have to be used. In contrast, in MgB(2) conductors an iron matrix may remain in direct contact with the superconducting core. The application of superconducting-magnetic heterostructures requires consideration of the thermal and electromagnetic stability of the superconducting materials used. On one hand, magnetic materials reduce the critical current gradient across the individual filaments but, on the other hand, they often reduce the thermal conductivity between the superconducting core and the cryogen, which may cause destruction of the conductor in the event of thermal instability. A possible nanoscale method of improving the critical current density of superconducting conductors is the introduction of sub-micron magnetic pinning centres. However, the volumetric density and chemical compatibility of magnetic inclusions has to be controlled to avoid suppression of the superconducting properties. PMID:21828430

  12. Proposal of new structure of MgB 2 wires with low AC loss for stator windings of fully superconducting motors located in iron core slots

    NASA Astrophysics Data System (ADS)

    Kajikawa, K.; Osaka, R.; Kuga, H.; Nakamura, T.; Wakuda, T.

    2011-11-01

    The new structure of MgB 2 monofilamentary wires for stator windings of fully superconducting motors is proposed to reduce their AC losses in iron core slots for the application of an alternating transport current. In order to validate the proposed structure of wire for loss reduction, numerical calculations are carried out by means of a finite element method using edge elements formulated with a self-field due to currents induced in an analysis region. It is assumed that the voltage-current characteristics of the MgB 2 superconductor are given by Bean’s critical state model, in which the critical current density is independent of the local magnetic field. The influences of wire structures on the AC losses are discussed quantitatively toward the optimum design of stator windings in fully superconducting motors with the MgB 2 wires.

  13. Accurate Insertion Loss Measurements of the Juno Patch Array Antennas

    NASA Technical Reports Server (NTRS)

    Chamberlain, Neil; Chen, Jacqueline; Hodges, Richard; Demas, John

    2010-01-01

    This paper describes two independent methods for estimating the insertion loss of patch array antennas that were developed for the Juno Microwave Radiometer instrument. One method is based principally on pattern measurements while the other method is based solely on network analyzer measurements. The methods are accurate to within 0.1 dB for the measured antennas and show good agreement (to within 0.1dB) of separate radiometric measurements.

  14. Measurement of solar cell ac parameters using the time domain technique

    NASA Astrophysics Data System (ADS)

    Deshmukh, M. P.; Kumar, R. Anil; Nagaraju, J.

    2004-08-01

    The instrumentation to measure solar cell ac parameters [cell capacitance (CP) and cell resistance (RP)] using the time domain technique is developed. The cell capacitance (CP) and series resistance (r) are calculated using open circuit voltage decay (OCVD) technique. It is calibrated with the help of an electrical network with passive components similar to ac equivalent circuit of a solar cell consisting of precision resistors and capacitors. The maximum error observed in the measurement of resistor and capacitor value is ±3.5%. The cell resistance (RP) is calculated from I-V characteristics of solar cell. The data obtained in time domain technique is compared with the impedance spectroscopy technique data measured on same solar cell and it is found that the deviation in cell capacitance and resistance are within ±8%.

  15. Effective method to measure back emfs and their harmonics of permanent magnet ac motors

    NASA Astrophysics Data System (ADS)

    Jiang, Q.; Bi, C.; Lin, S.

    2006-04-01

    As the HDD spindle motors become smaller and smaller, the back electromotive forces (emfs) measurement faces the new challenges due to their low inertias and small sizes. This article proposes a novel method to measure the back emfs and their harmonic components of PM ac motors only through a freewheeling procedure. To eliminate the influence of the freewheeling deceleration, the phase flux linkages are employed to obtain the back emf amplitudes and phases of the fundamental and harmonic components by using finite Fourier series analysis. The proposed method makes the freewheeling measurement of the back emfs and their harmonics accurate and fast. It is especially useful for the low inertia PM ac motors, such as spindle motors for small form factor HDDs.

  16. Quantifying the effects of roughness scattering on reflection loss measurements.

    PubMed

    Isakson, Marcia J; Chotiros, Nicholas P; Yarbrough, R Abraham; Piper, James N

    2012-12-01

    Seafloor reflection loss and roughness measurements were taken at the Experimental Validation of Acoustic Modeling Techniques experiment in 2006. The magnitude and phase of the reflection loss was measured at frequencies from 5 to 80 kHz and grazing angles from 7° to 77°. Approximately 1500 samples were taken for each angle. The roughness was measured with a laser profiler. Geoacoustic parameters such as water and sediment sound speed and density were measured concurrently. The reflection loss data were compared with three models: A flat interface elastic model based on geoacoustic measurements; a flat interface poro-elastic model based on the Biot/Stoll model; and a rough interface model based on the measured interface roughness power spectrum. The data were most consistent with the poro-elastic model including scattering. The elastic model consistently predicted values for the reflection loss which were higher than measured. The data exhibited more variability than the model due to layering and fluctuations in the propagating medium. PMID:23231100

  17. AC magnetic measurements of the ALS Booster Dipole Engineering Model Magnet

    SciTech Connect

    Green, M.I.; Keller, R.; Nelson, D.H.; Hoyer, E.

    1989-03-01

    10 Hz sine wave and 2 Hz sawtooth AC magnetic measurements of he curved ALS Booster Dipole Engineering Model Magnet have been accomplished. Long curved coils were utilized to measure the integral transfer function and uniformity. Point coils and a Hall Probe were used to measure magnetic induction and its uniformity. The data were logged and processed by a Tektronix 11401 digital oscilloscope. The dependence of the effective length on the field was determined from the ratio of the integral coil signals to the point coil signals. Quadrupole and sextupole harmonics were derived from the point and integral uniformity measurements. 5 refs., 4 figs., 2 tabs.

  18. Studies of superspin glass state and AC-losses in La0.7Sr0.3MnO3 nanoparticles obtained by high-energy ball-milling

    NASA Astrophysics Data System (ADS)

    Phong, P. T.; Manh, D. H.; Nguyen, L. H.; Tung, D. K.; Phuc, N. X.; Lee, I.-J.

    2014-11-01

    Single-phase perovskite compound La0.7Sr0.3MnO3 was synthesized by a high-energy ball milling method. Nanoparticle nature of this manganite with the average particle diameter of 11 nm was revealed from structure and morphology characterizations. The results of ac magnetic susceptibility measurements show that the system can be described as an ensemble of interacting magnetic nanoparticles, which indicates that the dipole-dipole interactions are strong enough to create superspin glass state in the sample. Furthermore, the specific loss power which is exhausted on the irradiation of an ensemble of particles with a magnetic field has been calculated and measured experimentally.

  19. Direct Measurement of Ab and Ac at the Z0 Pole Using a Lepton Tag

    NASA Astrophysics Data System (ADS)

    Abe, Kenji; Abe, Koya; Abe, T.; Adam, I.; Akagi, T.; Allen, N. J.; Arodzero, A.; Ash, W. W.; Aston, D.; Baird, K. G.; Baltay, C.; Band, H. R.; Barakat, M. B.; Bardon, O.; Barklow, T. L.; Bashindzhagyan, G. L.; Bauer, J. M.; Bellodi, G.; Ben-David, R.; Benvenuti, A. C.; Bilei, G. M.; Bisello, D.; Blaylock, G.; Bogart, J. R.; Bolen, B.; Bower, G. R.; Brau, J. E.; Breidenbach, M.; Bugg, W. M.; Burke, D.; Burnett, T. H.; Burrows, P. N.; Byrne, R. M.; Calcaterra, A.; Calloway, D.; Camanzi, B.; Carpinelli, M.; Cassell, R.; Castaldi, R.; Castro, A.; Cavalli-Sforza, M.; Chou, A.; Church, E.; Cohn, H. O.; Coller, J. A.; Convery, M. R.; Cook, V.; Cotton, R.; Cowan, R. F.; Coyne, D. G.; Crawford, G.; Damerell, C. J.; Danielson, M. N.; Daoudi, M.; de Groot, N.; dell'Orso, R.; Dervan, P. J.; de Sangro, R.; Dima, M.; D'Oliveira, A.; Dong, D. N.; Doser, M.; Dubois, R.; Eisenstein, B. I.; Eschenburg, V.; Etzion, E.; Fahey, S.; Falciai, D.; Fan, C.; Fernandez, J. P.; Fero, M. J.; Flood, K.; Frey, R.; Gillman, T.; Gladding, G.; Gonzalez, S.; Goodman, E. R.; Hart, E. L.; Harton, J. L.; Hasan, A.; Hasuko, K.; Hedges, S. J.; Hertzbach, S. S.; Hildreth, M. D.; Huber, J.; Huffer, M. E.; Hughes, E. W.; Huynh, X.; Hwang, H.; Iwasaki, M.; Jackson, D. J.; Jacques, P.; Jaros, J. A.; Jiang, Z. Y.; Johnson, A. S.; Johnson, J. R.; Johnson, R. A.; Junk, T.; Kajikawa, R.; Kalelkar, M.; Kamyshkov, Y.; Kang, H. J.; Karliner, I.; Kawahara, H.; Kim, Y. D.; King, R.; King, M. E.; Kofler, R. R.; Krishna, N. M.; Kroeger, R. S.; Langston, M.; Lath, A.; Leith, D. W.; Lia, V.; Lin, C.-J. S.; Liu, X.; Liu, M. X.; Loreti, M.; Lu, A.; Lynch, H. L.; Ma, J.; Mahjouri, M.; Mancinelli, G.; Manly, S.; Mantovani, G.; Markiewicz, T. W.; Maruyama, T.; Masuda, H.; Mazzucato, E.; McKemey, A. K.; Meadows, B. T.; Menegatti, G.; Messner, R.; Mockett, P. M.; Moffeit, K. C.; Moore, T. B.; Morii, M.; Muller, D.; Murzin, V.; Nagamine, T.; Narita, S.; Nauenberg, U.; Neal, H.; Nussbaum, M.; Oishi, N.; Onoprienko, D.; Osborne, L. S.; Panvini, R. S.; Park, H.; Park, C. H.; Pavel, T. J.; Peruzzi, I.; Piccolo, M.; Piemontese, L.; Pieroni, E.; Pitts, K. T.; Plano, R. J.; Prepost, R.; Prescott, C. Y.; Punkar, G. D.; Quigley, J.; Ratcliff, B. N.; Reeves, T. W.; Reidy, J.; Reinertsen, P. L.; Rensing, P. E.; Rochester, L. S.; Rowson, P. C.; Russell, J. J.; Saxton, O. H.; Schalk, T.; Schindler, R. H.; Schumm, B. A.; Schwiening, J.; Sen, S.; Serbo, V. V.; Shaevitz, M. H.; Shank, J. T.; Shapiro, G.; Sherden, D. J.; Shmakov, K. D.; Simopoulos, C.; Sinev, N. B.; Smith, S. R.; Smy, M. B.; Snyder, J. A.; Staengle, H.; Stahl, A.; Stamer, P.; Steiner, R.; Steiner, H.; Strauss, M. G.; Su, D.; Suekane, F.; Sugiyama, A.; Suzuki, S.; Swartz, M.; Szumilo, A.; Takahashi, T.; Taylor, F. E.; Thom, J.; Torrence, E.; Toumbas, N. K.; Usher, T.; Vannini, C.; Va'Vra, J.; Vella, E.; Venuti, J. P.; Verdier, R.; Verdini, P. G.; Wagner, S. R.; Wagner, D. L.; Waite, A. P.; Walston, S.; Wang, J.; Ward, C.; Watts, S. J.; Weidemann, A. W.; Weiss, E. R.; Whitaker, J. S.; White, S. L.; Wickens, F. J.; Williams, B.; Williams, D. C.; Williams, S. H.; Willocq, S.; Wilson, R. J.; Wisniewski, W. J.; Wittlin, J. L.; Woods, M.; Word, G. B.; Wright, T. R.; Wyss, J.; Yamamoto, R. K.; Yamartino, J. M.; Yang, X.; Yashima, J.; Yellin, S. J.; Young, C. C.; Yuta, H.; Zapalac, G.; Zdarko, R. W.; Zhou, J.

    1999-10-01

    The parity violation parameters Ab and Ac of the Zbb¯ and Zcc¯ couplings have been measured directly, using the polar angle dependence of the Z0-pole polarized cross sections. Bottom and charmed hadrons were tagged via semileptonic decays. Both the muon and electron identification algorithms take advantage of new multivariate techniques, incorporating for the first time information from the SLD Cˇerenkov Ring Imaging Detector. Based on the 1993-1995 SLD sample of 150 000 Z0 decays produced with highly polarized electron beams, we measure Ab = 0.910+/-0.068\\(stat\\)+/-0.037\\(syst\\), Ac = 0.642+/-0.110\\(stat\\)+/-0.063\\(syst\\).

  20. Versatile radar measurement of the electron loss rate in air

    SciTech Connect

    Dogariu, Arthur; Shneider, Mikhail N.; Miles, Richard B.

    2013-11-25

    We present an experimental method that makes possible in-situ measurements of the electron loss rate in arbitrary gas mixtures. A weakly ionized plasma is induced via resonant multiphoton ionization of trace amounts of nitric oxide seeded into the gas, and homodyne microwave scattering detection is used to study the dynamics of the electron loss mechanisms. Using this approach, the attachment rate for electrons to molecular oxygen in room temperature, atmospheric pressure air is determined. The measured 0.76 × 10{sup 8} s{sup −1} attachment rate is in very good agreement with predictions based on literature data.

  1. Calculation of atmospheric loss from microwave radiometric noise temperature measurements

    NASA Technical Reports Server (NTRS)

    Stelzried, C.; Slobin, S. D.

    1981-01-01

    Microwave propagation loss in the atmosphere can be inferred from microwave radiometric noise temperature measurements. The relevant equations are given and a derivation and calculation is made assuming various physical models. Comparison is made with the commonly used lumped element atmospheric model (isothermal and uniform loss) and the model with linear temperature and exponential loss distributions. The results are useful for estimating the integral inversion differences due to the model selection. This indicates that the commonly used lumped element atmospheric model is a very good approximation with judicious choice of the effective physical temperature. For the worst case comparison, the lumped element model agrees with the variable parameter model within 0.2 dB up to a propagation loss of 3 dB.

  2. Precise measurements of the energy losses of heavy ions

    SciTech Connect

    Bichsel, H.; Hiraoka, T. |

    1995-12-31

    Accurate measurements of the energy loss of all charged particles are needed to determine the reliability of the Bethe theory of stopping power. Few measurements have been made for particles with energies greater than 20 MeV/u. A first step to accurate measurements is to establish the precision of an experimental method. The authors report here about the recent energy loss measurements for 290 MeV/u carbon ions from the HIMAC. They have been made with the method used for 70 MeV protons. The ion beam traverses an absorber of thickness t and the residual range of the ions is measured with a water container of adjustable thickness (``range gauge``).

  3. Measuring breath acetone for monitoring fat loss: Review

    PubMed Central

    2015-01-01

    Objective Endogenous acetone production is a by‐product of the fat metabolism process. Because of its small size, acetone appears in exhaled breath. Historically, endogenous acetone has been measured in exhaled breath to monitor ketosis in healthy and diabetic subjects. Recently, breath acetone concentration (BrAce) has been shown to correlate with the rate of fat loss in healthy individuals. In this review, the measurement of breath acetone in healthy subjects is evaluated for its utility in predicting fat loss and its sensitivity to changes in physiologic parameters. Results BrAce can range from 1 ppm in healthy non‐dieting subjects to 1,250 ppm in diabetic ketoacidosis. A strong correlation exists between increased BrAce and the rate of fat loss. Multiple metabolic and respiratory factors affect the measurement of BrAce. BrAce is most affected by changes in the following factors (in descending order): dietary macronutrient composition, caloric restriction, exercise, pulmonary factors, and other assorted factors that increase fat metabolism or inhibit acetone metabolism. Pulmonary factors affecting acetone exchange in the lung should be controlled to optimize the breath sample for measurement. Conclusions When biologic factors are controlled, BrAce measurement provides a non‐invasive tool for monitoring the rate of fat loss in healthy subjects. PMID:26524104

  4. Dynamic fluid-loss measurement of oil-mud additives

    SciTech Connect

    Wyant, R.E.; Reed, R.; Sifferman, T.R.; Wooten, S.O.

    1987-03-01

    The objective of this laboratory study was to correlate the dynamic fluid loss (DFL) with the static (API high-temperature/high-pressure (HTHP)) fluid loss, the sticking coefficient, and the fluid-loss-control-agent (FLCA) concentration in oil muds. This was done as a continuing effort to use oil-mud FLCA's more efficiently in the field and to reduce pipe-sticking problems associated with deviated holes. Data were obtained with 13-lbm/gal (1558-kg/m/sup 3/) inverted-emulsion muds by use of four different types of FLCA's over wide concentration ranges, but within the limits of reasonable field usage. The DFL data (at 250/sup 0/F (121/sup 0/C) and 500-psi (3447-kPa) differential pressure) were obtained with newly developed cells in which filtration occurs in an annulus around a central permeable core. An asymmetric buildup of mud solids and fluid channeling in the annulus suggest a mechanism that would greatly increase pipe-sticking tendencies in deviated wellbores. The DFL decreased with decreasing static fluid loss. The laboratory-measured sticking coefficient, which should correlate with differential-pressure sticking in the field, was reduced as fluid loss decreased. The fluid loss generally decreased with increasing FLCA concentrations, with the major reductions occurring at concentrations of about 4 lbm/bbl (11.4 kg/m/sup 3/).

  5. Using Curriculum-Based Measurement to Examine Summer Learning Loss

    ERIC Educational Resources Information Center

    Sandberg Patton, Karen L.; Reschly, Amy L.

    2013-01-01

    Summer loss of reading is a potential factor in maintaining, and potentially widening, the achievement gap. This study used curriculum-based measurement of reading (R-CBM) to investigate the effect of the summer on reading. For this study, 317 students in Grades 2 to 5 were assessed in the spring and fall using Dynamic Indicators of Basic Early…

  6. Ozone Production and Loss Rate Measurements in the Middle Stratosphere

    NASA Technical Reports Server (NTRS)

    Jucks, Kenneth W.; Johnson, David G.; Chance, K. V.; Traub, Wesley A.; Salawitch, R. J.; Stachnik, R. A.

    1996-01-01

    The first simultaneous measurements of HO(x), NO(x), and Cl(x) radicals in the middle stratosphere show that NO(x) catalytic cycles dominate loss of ozone (O3) for altitudes between 24 and 38 km; Cl(x) catalytic cycles are measured to be less effective than previously expected; and there is no 'ozone deficit' in the photochemically dominated altitude range from 31 and 38 km, contrary to some previous theoretical studies.

  7. Direct measurements of Ab and Ac using vertex and kaon charge tags at the SLAC detector.

    PubMed

    Abe, Koya; Abe, Kenji; Abe, T; Adam, I; Akimoto, H; Aston, D; Baird, K G; Baltay, C; Band, H R; Barklow, T L; Bauer, J M; Bellodi, G; Berger, R; Blaylock, G; Bogart, J R; Bower, G R; Brau, J E; Breidenbach, M; Bugg, W M; Burke, D; Burnett, T H; Burrows, P N; Calcaterra, A; Cassell, R; Chou, A; Cohn, H O; Coller, J A; Convery, M R; Cook, V; Cowan, R F; Crawford, G; Damerell, C J S; Daoudi, M; Dasu, S; de Groot, N; de Sangro, R; Dong, D N; Doser, M; Dubois, R; Erofeeva, I; Eschenburg, V; Etzion, E; Fahey, S; Falciai, D; Fernandez, J P; Flood, K; Frey, R; Hart, E L; Hasuko, K; Hertzbach, S S; Huffer, M E; Huynh, X; Iwasaki, M; Jackson, D J; Jacques, P; Jaros, J A; Jiang, Z Y; Johnson, A S; Johnson, J R; Kajikawa, R; Kalelkar, M; Kang, H J; Kofler, R R; Kroeger, R S; Langston, M; Leith, D W G; Lia, V; Lin, C; Mancinelli, G; Manly, S; Mantovani, G; Markiewicz, T W; Maruyama, T; McKemey, A K; Messner, R; Moffeit, K C; Moore, T B; Morii, M; Muller, D; Murzin, V; Narita, S; Nauenberg, U; Neal, H; Nesom, G; Oishi, N; Onoprienko, D; Osborne, L S; Panvini, R S; Park, C H; Peruzzi, I; Piccolo, M; Piemontese, L; Plano, R J; Prepost, R; Prescott, C Y; Ratcliff, B N; Reidy, J; Reinertsen, P L; Rochester, L S; Rowson, P C; Russell, J J; Saxton, O H; Schalk, T; Schumm, B A; Schwiening, J; Serbo, V V; Shapiro, G; Sinev, N B; Snyder, J A; Staengle, H; Stahl, A; Stamer, P; Steiner, H; Su, D; Suekane, F; Sugiyama, A; Suzuki, A; Swartz, M; Taylor, F E; Thom, J; Torrence, E; Usher, T; Va'vra, J; Verdier, R; Wagner, D L; Waite, A P; Walston, S; Weidemann, A W; Weiss, E R; Whitaker, J S; Williams, S H; Willocq, S; Wilson, R J; Wisniewski, W J; Wittlin, J L; Woods, M; Wright, T R; Yamamoto, R K; Yashima, J; Yellin, S J; Young, C C; Yuta, H

    2005-03-11

    Exploiting the manipulation of the SLAC Linear Collider electron-beam polarization, we present precise direct measurements of the parity-violation parameters A(c) and A(b) in the Z-boson-c-quark and Z-boson-b-quark coupling. Quark-antiquark discrimination is accomplished via a unique algorithm that takes advantage of the precise SLAC Large Detector charge coupled device vertex detector, employing the net charge of displaced vertices as well as the charge of kaons that emanate from those vertices. From the 1996-1998 sample of 400 000 Z decays, produced with an average beam polarization of 73.4%, we find A(c)=0.673+/-0.029(stat)+/-0.023(syst) and A(b)=0.919+/-0.018(stat)+/-0.017(syst). PMID:15783953

  8. Direct Detection of Pure ac Spin Current by X-Ray Pump-Probe Measurements.

    PubMed

    Li, J; Shelford, L R; Shafer, P; Tan, A; Deng, J X; Keatley, P S; Hwang, C; Arenholz, E; van der Laan, G; Hicken, R J; Qiu, Z Q

    2016-08-12

    Despite recent progress in spin-current research, the detection of spin current has mostly remained indirect. By synchronizing a microwave waveform with synchrotron x-ray pulses, we use the ferromagnetic resonance of the Py (Ni_{81}Fe_{19}) layer in a Py/Cu/Cu_{75}Mn_{25}/Cu/Co multilayer to pump a pure ac spin current into the Cu_{75}Mn_{25} and Co layers, and then directly probe the spin current within the Cu_{75}Mn_{25} layer and the spin dynamics of the Co layer by x-ray magnetic circular dichroism. This element-resolved pump-probe measurement unambiguously identifies the ac spin current in the Cu_{75}Mn_{25} layer. PMID:27563981

  9. Direct Detection of Pure ac Spin Current by X-Ray Pump-Probe Measurements

    NASA Astrophysics Data System (ADS)

    Li, J.; Shelford, L. R.; Shafer, P.; Tan, A.; Deng, J. X.; Keatley, P. S.; Hwang, C.; Arenholz, E.; van der Laan, G.; Hicken, R. J.; Qiu, Z. Q.

    2016-08-01

    Despite recent progress in spin-current research, the detection of spin current has mostly remained indirect. By synchronizing a microwave waveform with synchrotron x-ray pulses, we use the ferromagnetic resonance of the Py (Ni81Fe19 ) layer in a Py /Cu /Cu75Mn25/Cu /Co multilayer to pump a pure ac spin current into the Cu75Mn25 and Co layers, and then directly probe the spin current within the Cu75Mn25 layer and the spin dynamics of the Co layer by x-ray magnetic circular dichroism. This element-resolved pump-probe measurement unambiguously identifies the ac spin current in the Cu75Mn25 layer.

  10. Racetrack resonator as a loss measurement platform for photonic components

    DOE PAGESBeta

    Jones, Adam M.; Univ. of Arizona, Tucson, AZ; DeRose, Christopher T.; Lentine, Anthony L.; Starbuck, Andrew; Pomerene, Andrew T. S.; Norwood, Robert A.

    2015-10-27

    This work represents the first complete analysis of the use of a racetrack resonator to measure the insertion loss of efficient, compact photonic components. Beginning with an in-depth analysis of potential error sources and a discussion of the calibration procedure, the technique is used to estimate the insertion loss of waveguide width tapers of varying geometry with a resulting 95% confidence interval of 0.007 dB. Furthermore, the work concludes with a performance comparison of the analyzed tapers with results presented for four taper profiles and three taper lengths.

  11. Recent Advances in AC-DC Transfer Measurements Using Thin-Film Thermal Converters

    SciTech Connect

    WUNSCH,THOMAS F.; KINARD,JOSEPH R.; MANGINELL,RONALD P.; LIPE,THOMAS E.; SOLOMON JR.,OTIS M.; JUNGLING,KENNETH C.

    2000-12-08

    New standards for ac current and voltage measurements, thin-film multifunction thermal converters (MJTCS), have been fabricated using thin-film and micro-electro-mechanical systems (MEMS) technology. Improved sensitivity and accuracy over single-junction thermoelements and targeted performance will allow new measurement approaches in traditionally troublesome areas such as the low frequency and high current regimes. A review is presented of new microfabrication techniques and packaging methods that have resulted from a collaborative effort at Sandia National Laboratories and the National Institute of Standards and Technology (MHZ).

  12. Measurement of texture loss for JPEG 2000 compression

    NASA Astrophysics Data System (ADS)

    Burns, Peter D.; Williams, Don

    2012-01-01

    The capture and retention of image detail are important characteristics for system design and subsystem selection. An established imaging performance measure that is well suited to certain sources of detail loss, such as optical focus and motion blur, is the Modulation Transfer Function (MTF). Recently we have seen the development of image quality methods aimed at more adaptive operations, such as noise cleaning and adaptive digital filtering. An example of this is the measure of texture (image detail) loss using sets of overlapping small objects, known as dead leaves targets. In this paper we investigate the application of the above method to image compression. We apply several levels of JPEG and JPEG 2000 compression to digital images that include scene content that is amenable to the texture loss measure. A modified form of the method was used. This allowed direct target compensation without data smoothing. Following a camera simulation, the texture MTF and acutance were computed. The standard deviation of the acutance measure was 0.014 (relative error of 1.63%), found by replicate measurements. Structured similarity index (SSIM) values, used for still and video image quality evaluation, were also computed for the image sets. The acutance and SSI results were similar; however the relationship between the two showed an offset between the JPEG and JPEG 2000 images sets.

  13. A wide-frequency range AC magnetometer to measure the specific absorption rate in nanoparticles for magnetic hyperthermia

    NASA Astrophysics Data System (ADS)

    Garaio, E.; Collantes, J. M.; Garcia, J. A.; Plazaola, F.; Mornet, S.; Couillaud, F.; Sandre, O.

    2014-11-01

    Measurement of specific absorption rate (SAR) of magnetic nanoparticles is crucial to assert their potential for magnetic hyperthermia. To perform this task, calorimetric methods are widely used. However, those methods are not very accurate and are difficult to standardize. In this paper, we present AC magnetometry results performed with a lab-made magnetometer that is able to obtain dynamic hysteresis-loops in the AC magnetic field frequency range from 50 kHz to 1 MHz and intensities up to 24 kA m-1. In this work, SAR values of maghemite nanoparticles dispersed in water are measured by AC magnetometry. The so-obtained values are compared with the SAR measured by calorimetric methods. Both measurements, by calorimetry and magnetometry, are in good agreement. Therefore, the presented AC magnetometer is a suitable way to obtain SAR values of magnetic nanoparticles.

  14. Theory of the ac spin valve effect: a new method to measure spin relaxation time

    NASA Astrophysics Data System (ADS)

    Kochan, Denis; Gmitra, Martin; Fabian, Jaroslav

    2012-02-01

    Parallel (P) and antiparallel (AP) configurations of FNF junctions have, in a dc regime, different resistivities (RAP>RP), giving rise to the giant magnetoresistance (GMR) effect, which can be explained within the spin injection drift-diffusion model. We extend the model to include ac phenomena and predict new spin dynamical phenomenon; the resonant amplification and depletion of spin accumulation in the P and AP configurations, respectively. As the major new effect, the spin valve magnetoimpedance of the FNF junction oscillates with the driving ac frequency, which leads to negative GMR effect (|ZAP|<|ZP|). We show that from the spin-valve oscillation periods, measured all electrically in the GHz regime, the spin relaxation times could be extracted without any magnetic field and sample size changes (contrary to other techniques). For thin tunnel junctions the ac signal becomes pure Lorentzian, also enabling one to obtain the spin relaxation time of the N region from the signal width. This work, was published in Physical Review Letters,10, 176604 (2011).

  15. Measurement of respiratory water loss in newborn lambs.

    PubMed

    Hammarlund, K; Riesenfeld, T; Sedin, G

    1986-05-01

    A flow-through system for measurement of respiratory water loss, providing data on oxygen consumption and carbon dioxide production, is described. The system uses a mass spectrometer, specially equipped with a water channel, for analysis of gas concentrations. To avoid condensation of water vapour, the tubing in the flow-through system is heated. The method was tested by evaporating known amounts of water, and was found to be very accurate with a correlation coefficient of 0.999. Measurements were made in 10 fullterm lambs of varying postnatal age (4-15 days) and a mean respiratory water loss (RWL) of 11.7 mg kg-1 min-1 was found at rest. The RWL decreased with increasing postnatal age, as did oxygen consumption. The RWL at rest was influenced by the ambient relative humidity, with higher values at lower humidities. PMID:3088913

  16. Determining Transmission Loss from Measured External and Internal Acoustic Environments

    NASA Technical Reports Server (NTRS)

    Scogin, Tyler; Smith, A. M.

    2012-01-01

    An estimate of the internal acoustic environment in each internal cavity of a launch vehicle is needed to ensure survivability of Space Launch System (SLS) avionics. Currently, this is achieved by using the noise reduction database of heritage flight vehicles such as the Space Shuttle and Saturn V for liftoff and ascent flight conditions. Marshall Space Flight Center (MSFC) is conducting a series of transmission loss tests to verify and augment this method. For this test setup, an aluminum orthogrid curved panel representing 1/8th of the circumference of a section of the SLS main structure was mounted in between a reverberation chamber and an anechoic chamber. Transmission loss was measured across the panel using microphones. Data measured during this test will be used to estimate the internal acoustic environments for several of the SLS launch vehicle internal spaces.

  17. 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.

  18. The Multidimensional Loss Scale: validating a cross-cultural instrument for measuring loss.

    PubMed

    Vromans, Lyn; Schweitzer, Robert D; Brough, Mark

    2012-04-01

    The Multidimensional Loss Scale (MLS) represents the first instrument designed specifically to index Experience of Loss Events and Loss Distress across multiple domains (cultural, social, material, and intrapersonal) relevant to refugee settlement. Recently settled Burmese adult refugees (N = 70) completed a questionnaire battery, including MLS items. Analyses explored MLS internal consistency, convergent and divergent validity, and factor structure. Cronbach alphas indicated satisfactory internal consistency for Experience of Loss Events (0.85) and Loss Distress (0.92), reflecting a unitary construct of multidimensional loss. Loss Distress did not correlate with depression or anxiety symptoms and correlated moderately with interpersonal grief and trauma symptoms, supporting divergent and convergent validity. Factor analysis provided preliminary support for a five-factor model: Loss of Symbolic Self, Loss of Interdependence, Loss of Home, Interpersonal Loss, and Loss of Intrapersonal Integrity. Received well by participants, the new scale shows promise for application in future research and practice. PMID:22456590

  19. Charged fusion product loss measurements using nuclear activation.

    PubMed

    Bonheure, G; Hult, M; González de Orduña, R; Arnold, D; Dombrowski, H; Laubenstein, M; Wieslander, E; Vermaercke, P; Murari, A; Popovichev, S; Mlynar, J

    2010-10-01

    In ITER, α particle loss measurements will be required in order to understand the alpha particle physics. Techniques capable of operating in a fusion reactor environment need further development. Recent experimental studies on JET demonstrated the potential of nuclear activation to measure the flux of escaping MeV ions. New results from MeV ion induced activation of metallic, ceramic, and crystal samples placed near the plasma edge are reported. Activation products were measured as function of orientation with respect to the magnetic field as well as function of the distance to the plasma. Sample activity was measured using ultralow-level gamma-ray spectrometry. Distribution of 14.68 MeV fusion proton induced activation products is strongly anisotropic in agreement with simulations and falls off sharply with increasing distance to the plasma. Prospects for using the technique in ITER are discussed. PMID:21058458

  20. Dielectric loss measurements using an embedded transmission line resonator

    NASA Astrophysics Data System (ADS)

    Sarabi, Bahman; Stoutimore, M. J. A.; Khalil, Moe; Gladchenko, Sergiy; Kozen, Alexander; Rubloff, Gary; Wellstood, F. C.; Lobb, J. C.; Osborn, K. D.

    2011-03-01

    Lossy dielectrics are a major source of decoherence in superconducting qubits. Superconducting linear resonators have proven to be ideally suited for measuring loss in different dielectrics due to their versatility and relative simplicity in design, fabrication, and measurement. We will present data from samples where the low-loss coplanar resonators are fabricated on top of AlOx dielectric films grown using atomic layer deposition (ALD). Although the low-power loss can be extracted from this geometry, embedding the dielectric under study between metal films has advantages that we will discuss. In addition, ALD films can be grown conformally and without pinholes to small thicknesses in comparison to conventional PECVD films. This allows us to make lumped-element resonators with a relatively small footprint, which can easily be embedded within the transmission line. This research was supported by the Intelligence Advanced Research Projects Activity through the U.S. Army Research Office award No. W911NF-09-1-0351.

  1. AC hot wire measurement of thermophysical properties of nanofluids with 3ω method

    NASA Astrophysics Data System (ADS)

    Turgut, A.; Sauter, C.; Chirtoc, M.; Henry, J. F.; Tavman, S.; Tavman, I.; Pelzl, J.

    2008-01-01

    We present a new application of a hot wire sensor for simultaneous and independent measurement of thermal conductivity k and diffusivity α of (nano)fluids, based on a hot wire thermal probe with ac excitation and 3 ω lock-in detection. The theoretical modeling of imaginary part of the signal yields the k value while the phase yields the α value. Due to modulated heat flow in cylindrical geometry with a radius comparable to the thermal diffusion length, the necessary sample quantity is kept very low, typically 25 μl. In the case of relative measurements, the resolution is 0.1% in k and 0.3% in α. Measurements of water-based Aerosil 200V nanofluids indicate that ultrasound treatment is more efficient than high pressure dispersion method in enhancing their thermal parameters.

  2. An AC constant-response method for electrophysiological measurements of spectral sensitivity functions.

    PubMed

    de Souza, J M; DeVoe, R D; Schoeps, C; Ventura, D F

    1996-10-01

    A number of methods have been used in the past to measure spectral sensitivity (S(lambda)) functions of electric responses in the visual system. We present here a microcomputer based, AC, constant-response method for automatic on-line measurement of S(lambda) in cells with or without a sustained tonic response. It is based on feedback adjustment of light intensity to obtain constant peak-to-peak amplitudes of response to a flickering stimulus as the spectrum is scanned between 300 and 700 nm in 4 nm steps. It combines the advantages of: (1) on-line presentation of S(lambda) curves; (2) constant light adaptation; (3) sampling of many points; and (4) fast data collection time. The system can be applied to sensitivity or threshold (e.g., S(lambda), dark adaptation, receptive field) measurements of any electrically recorded visual response. PMID:8912193

  3. Comparison of AC losses, magnetic field/current distributions and critical currents of superconducting circular pancake coils and infinitely long stacks using coated conductors

    NASA Astrophysics Data System (ADS)

    Yuan, Weijia; Campbell, A. M.; Hong, Z.; Ainslie, M. D.; Coombs, T. A.

    2010-08-01

    A model is presented for calculating the AC losses, magnetic field/current density distribution and critical currents of a circular superconducting pancake coil. The assumption is that the magnetic flux lines will lie parallel to the wide faces of tapes in the unpenetrated area of the coil. Instead of using an infinitely long stack to approximate the circular coil, this paper gives an exact circular coil model using elliptic integrals. A new efficient numerical method is introduced to yield more accurate and fast computation. The computation results are in good agreement with the assumptions. For a small value of the coil radius, there is an asymmetry along the coil radius direction. As the coil radius increases, this asymmetry will gradually decrease, and the AC losses and penetration depth will increase, but the critical current will decrease. We find that if the internal radius is equal to the winding thickness, the infinitely long stack approximation overestimates the loss by 10% and even if the internal radius is reduced to zero, the error is still only 60%. The infinitely long stack approximation is therefore adequate for most practical purposes. In addition, the comparison result shows that the infinitely long stack approximation saves computation time significantly.

  4. Towards a smart non-invasive fluid loss measurement system.

    PubMed

    Suryadevara, N K; Mukhopadhyay, S C; Barrack, L

    2015-04-01

    In this article, a smart wireless sensing non-invasive system for estimating the amount of fluid loss, a person experiences while physical activity is presented. The system measures three external body parameters, Heart Rate, Galvanic Skin Response (GSR, or skin conductance), and Skin Temperature. These three parameters are entered into an empirically derived formula along with the user's body mass index, and estimation for the amount of fluid lost is determined. The core benefit of the developed system is the affluence usage in combining with smart home monitoring systems to care elderly people in ambient assisted living environments as well in automobiles to monitor the body parameters of a motorist. PMID:25686913

  5. Time-resolved Measurements of Spontaneous Magnetic Deflagration of Mn12 tBuAc

    NASA Astrophysics Data System (ADS)

    Chen, Yizhang; Kent, A. D.; Zhang, Qing; Sarachik, M. P.; Baker, M. L.; Garanin, D. A.; Mhesn, Najah; Lampropoulos, Christos

    Magnetic deflagration in molecular magnets has been triggered by heat pulses and acoustic waves. In this work we report spontaneous magnetic deflagration (i.e. deflagration that occurs without an external trigger) in the axially symmetric single molecule magnet Mn12 tBuAc . Magnetic hysteresis measurements show steps due to resonant quantum tunneling (RQT) below 1K, confirming the spin-Hamiltonian parameters for this material and previous results. Deflagration speeds measured with a newly constructed higher bandwidth (2MHz) setup will be presented as a function of transverse and longitudinal fields Hx ⊗Hz both on and off resonance. A large increase in front velocity near RQT steps is observed in experiments with swept transverse fields and will be discussed in light of models of deflagration. Work supported by NSF-DMR-1309202 (NYU); ARO W911NF-13-1-0125 (CCNY); DMR-1161571(Lehman); Cottrell College Science Award (UNF).

  6. Test Results of the AC Field Measurements of Fermilab Booster Corrector Magnets

    SciTech Connect

    DiMarco, E.Joseph; Harding, D.J.; Kashikhin, V.S.; Kotelnikov, S.K.; Lamm, M.J.; Makulski, A.; Nehring, R.; Orris, D.F.; Schlabach, P.; Sylvester, C.; Tartaglia, Michael Albert; /Fermilab

    2008-06-25

    Multi-element corrector magnets are being produced at Fermilab that enable correction of orbits and tunes through the entire cycle of the Booster, not just at injection. The corrector package includes six different corrector elements--normal and skew orientations of dipole, quadrupole, and sextupole--each independently powered. The magnets have been tested during typical AC ramping cycles at 15Hz using a fixed coil system to measure the dynamic field strength and field quality. The fixed coil is comprised of an array of inductive pick-up coils around the perimeter of a cylinder which are sampled simultaneously at 100 kHz with 24-bit ADC's. The performance of the measurement system and a summary of the field results are presented and discussed.

  7. Spectral Measurements from the Optical Emission of the A.C. Plasma Anemometer

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    The optical emission properties of a new class of AC-driven flow sensors based on a glow discharge (plasma) is presented. These results extend the utility of the plasma sensor that has recently been developed for measurements in high-enthalpy flows. The plasma sensor utilizes a high frequency (1MHz) AC discharge between two electrodes as the main sensing element. The voltage drop across the discharge correlates to changes in the external flow which can be calibrated for mass-flux (ρU) or pressure depending on the design of the electrodes and orientation relative to the free-stream flow direction. Recent experiments examine the potential for spectral analysis of the optical emission of the discharge to provide additional insight to the flow field. These experiments compare the optical emission of the plasma to emission from breakdown due to an ND:YAG laser. The oxygen 777.3 nm band in particular is a focus of interest as a marker for the determination of gas density.

  8. Measurement of transepidermal water loss in localized scleroderma.

    PubMed

    Ďurčanská, Veronika; Jedličková, Hana; Vašků, Vladimír

    2016-05-01

    Localized scleroderma (LS) is a disease characterized by fibrotic changes in the dermis. Connective tissue growth factor and transforming growth factor β2 are the main mediators of fibrogenesis; this, along with excessive connective tissue production, affects epidermal keratinocytes, and thereby contributes to the changed quality of skin barrier. The objective of this article was to study the objective measurement of the skin barrier quality in LS with transepidermal water loss (TEWL) meter. The measurements of TEWL were performed on LS plaques in all three stages of various body locations. Control measurements were made on the contralateral side of healthy skin. The difference between TEWL in LS area and the contralateral side of the healthy skin was evaluated. A higher average TEWL 7.86 g/m(2) /h (SD 5.29) was observed on LS plaques compared with the control measurements on healthy skin 6.39 g/m(2) /h (SD 2.77). TEWL average values decreased from the inflammatory stage, through the sclerotic and to the atrophic stage. The mean difference 1.301 g/m(2) /h (SD 5.16) was found between TEWL on LS plaques and on the contralateral healthy skin in 82 measurements, i.e., a higher TEWL was observed in LS. The difference was statistically significant with p = 0.0250. Although fibrogenesis in scleroderma is localized in dermis, the skin barrier changes can be detected. PMID:26970329

  9. Simple uniaxial pressure device for ac-susceptibility measurements suitable for closed cycle refrigerator system.

    PubMed

    Arumugam, S; Manivannan, N; Murugeswari, A

    2007-06-01

    A simple design of the uniaxial pressure device for the measurement of ac-susceptibility at low temperatures using closed cycle refrigerator system is presented for the first time. This device consists of disc micrometer, spring holder attachment, uniaxial pressure cell, and the ac-susceptibility coil wound on stycast bobbin. It can work under pressure till 0.5 GPa and at the temperature range of 30-300 K. The performance of the system at ambient pressure is tested and calibrated with standard paramagnetic salts [Gd(2)O(3), Er(2)O(3), and Fe(NH(4)SO(4))(2)6H(2)O], Fe(3)O(4), Gd metal, Dy metal, superconductor (YBa(2)Cu(3)O(7)), manganite (La(1.85)Ba(0.15)MnO(3)), and spin glass material (Pr(0.8)Sr(0.2)MnO(3)). The performance of the uniaxial pressure device is demonstrated by investigating the uniaxial pressure dependence of La(1.85)Ba(0.15)MnO(3) single crystal with P||c axis. The Curie temperature (T(c)) decreases as a function of pressure with P||c axis (dT(c)dP(||c axis)=-11.65 KGPa) up to 46 MPa. The design is simple, is user friendly, and does not require pressure calibration. Measurement can even be made on thin and small size oriented crystals. The failure of the coil is remote under uniaxial pressure. The present setup can be used as a multipurpose uniaxial pressure device for the measurement of Hall effect and thermoelectric power with a small modification in the pressure cell. PMID:17614625

  10. Study of AC Magnetic Properties and Core Losses of Fe/Fe3O4-epoxy Resin Soft Magnetic Composite

    NASA Astrophysics Data System (ADS)

    Laxminarayana, T. A.; Manna, Subhendu Kumar; Fernandes, B. G.; Venkataramani, N.

    Soft Magnetic Composites (SMC) were prepared by coating of nanocrystalline Fe3O4 particles, synthesized by co-precipitation method, on atomized iron powder of particle size less than 53 μm in size using epoxy resin as a binder between iron and Fe3O4. Fe3O4 was chosen, for its high electric resistivity and suitable magnetic properties, to keep the coating layer magnetic and seek improvement to the magnetic properties of SMC. SEM images and XRD patterns were recorded in order to investigate the coatings on the surface of iron powder. A toroid was prepared by cold compaction of coated iron powder at 1050 MPa and subsequently cured at 150˚C for 1 hr in argon atmosphere. For comparison of properties, a toroid of uncoated iron powder was also compacted at 1050 MPa and annealed at 600˚C for 2 hr in argon atmosphere. The coated iron powder composite has a resistivity of greater than 200 μΩm, measured by four probe method. A comparison of Magnetic Hysteresis loops and core losses using B-H Loop tracer in the frequency range 0 to 1500 Hz on the coated and uncoated iron powder is reported.

  11. Measurement of the permittivity and loss of high-loss materials using a Near-Field Scanning Microwave Microscope.

    PubMed

    Gregory, A P; Blackburn, J F; Lees, K; Clarke, R N; Hodgetts, T E; Hanham, S M; Klein, N

    2016-02-01

    In this paper improvements to a Near-Field Scanning Microwave Microscope (NSMM) are presented that allow the loss of high loss dielectric materials to be measured accurately at microwave frequencies. This is demonstrated by measuring polar liquids (loss tangent tanδ≈1) for which traceable data is available. The instrument described uses a wire probe that is electromagnetically coupled to a resonant cavity. An optical beam deflection system is incorporated within the instrument to allow contact mode between samples and the probe tip to be obtained. Liquids are contained in a measurement cell with a window of ultrathin glass. The calibration process for the microscope, which is based on image-charge electrostatic models, has been adapted to use the Laplacian 'complex frequency'. Measurements of the loss tangent of polar liquids that are consistent with reference data were obtained following calibration against single-crystal specimens that have very low loss. PMID:26686660

  12. Measurement of the ac Stark shift with a guided matter-wave interferometer

    NASA Astrophysics Data System (ADS)

    Deissler, B.; Hughes, K. J.; Burke, J. H. T.; Sackett, C. A.

    2008-03-01

    The dynamic polarizability of Rb87 atoms was measured using a guided-wave Bose-Einstein condensate interferometer. Taking advantage of the large arm separations obtainable in our device, a well-calibrated laser beam is applied to one atomic packet and not the other, inducing a differential phase shift. The technique requires relatively low laser intensity and works for arbitrary optical frequencies. For off-resonant light, the ac polarizability is obtained with a statistical accuracy of 3% and a calibration uncertainty of 6%. On resonance, the dispersion-shaped behavior of the Stark shift is observed, but with a broadened linewidth that is attributed to collective light scattering effects. The resulting nonlinearity may prove useful for the production and control of squeezed quantum states.

  13. AC-Conductivity Measure from Heat Production of Free Fermions in Disordered Media

    NASA Astrophysics Data System (ADS)

    Bru, J.-B.; de Siqueira Pedra, W.; Hertling, C.

    2016-05-01

    We extend (Bru et al. in J Math Phys 56:051901-1-51, 2015) in order to study the linear response of free fermions on the lattice within a (independently and identically distributed) random potential to a macroscopic electric field that is time- and space-dependent. We obtain the notion of a macroscopic AC-conductivity measure which only results from the second principle of thermodynamics. The latter corresponds here to the positivity of the heat production for cyclic processes on equilibrium states. Its Fourier transform is a continuous bounded function which is naturally called (macroscopic) conductivity. We additionally derive Green-Kubo relations involving time-correlations of bosonic fields coming from current fluctuations in the system. This is reminiscent of non-commutative central limit theorems.

  14. An AC phase measuring interferometer for measuring dn/dT of fused silica and calcium fluoride at 193 nm

    SciTech Connect

    Shagam, R.N.

    1998-09-01

    A novel method for the measurement of the change in index of refraction vs. temperature (dn/dT) of fused silica and calcium fluoride at the 193 nm wavelength has been developed in support of thermal modeling efforts for the development of 193 nm-based photolithographic exposure tools. The method, based upon grating lateral shear interferometry, uses a transmissive linear grating to divide a 193 nm laser beam into several beam paths by diffraction which propagate through separate identical material samples. One diffracted order passing through one sample overlaps the undiffracted beam from a second sample and forms interference fringes dependent upon the optical path difference between the two samples. Optical phase delay due to an index change from heating one of the samples causes the interference fringes to change sinusoidally with phase. The interferometer also makes use of AC phase measurement techniques through lateral translation of the grating. Results for several samples of fused silica and calcium fluoride are demonstrated.

  15. Quantitative Thermal Microscopy Measurement with Thermal Probe Driven by dc+ac Current

    NASA Astrophysics Data System (ADS)

    Bodzenta, Jerzy; Juszczyk, Justyna; Kaźmierczak-Bałata, Anna; Firek, Piotr; Fleming, Austin; Chirtoc, Mihai

    2016-07-01

    Quantitative thermal measurements with spatial resolution allowing the examination of objects of submicron dimensions are still a challenging task. The quantity of methods providing spatial resolution better than 100 nm is very limited. One of them is scanning thermal microscopy (SThM). This method is a variant of atomic force microscopy which uses a probe equipped with a temperature sensor near the apex. Depending on the sensor current, either the temperature or the thermal conductivity distribution at the sample surface can be measured. However, like all microscopy methods, the SThM gives only qualitative information. Quantitative measuring methods using SThM equipment are still under development. In this paper, a method based on simultaneous registration of the static and the dynamic electrical resistances of the probe driven by the sum of dc and ac currents, and examples of its applications are described. Special attention is paid to the investigation of thin films deposited on thick substrates. The influence of substrate thermal properties on the measured signal and its dependence on thin film thermal conductivity and film thickness are analyzed. It is shown that in the case where layer thicknesses are comparable or smaller than the probe-sample contact diameter, a correction procedure is required to obtain actual thermal conductivity of the layer. Experimental results obtained for thin SiO2 and BaTiO_{3 }layers with thicknesses in the range from 11 nm to 100 nm are correctly confirmed with this approach.

  16. Scaling law and general expression for transport ac loss of a rectangular thin strip with power-law E(J) relation

    NASA Astrophysics Data System (ADS)

    Chen, Du-Xing; Li, Shuo; Fang, Jin

    2015-12-01

    Transport ac loss Q of a superconducting rectangular thin strip obeying a power-law relation E∝Jn as a function of current amplitude Im may be, following Norris, expressed by normalized quantities as q(im). A scaling law is deduced that if Icf, Ic and f being the critical current and frequency, is multiplied by a positive constant C, then im and qm are multiplied by C 1 /(n - 1)and C 2 /(n - 1) , respectively. Based on this scaling law and the well-known Norris formula, the general function of q(im, n, f) is obtained graphically or analytically for any practical purpose, after accurate numerical computations on a set of q(im) at several values of n and a fixed value of f.

  17. Measurement of klystron phase modulation due to ac-powered filaments

    NASA Technical Reports Server (NTRS)

    Finnegan, E. J.

    1977-01-01

    A technique for determining the intermodulation components in the RF spectrum of the S-band radar transmitter generated by having the klystron filaments heated by 400-Hz ac power is described. When the klystron is being operated with 400-Hz (ac) on the filament, the IPM is buried in the 400-Hz equipment interference noise. The modulation sidebands were separated and identified and found to be-67 db below the main carrier. This is well below the transmitter specifications, and operating the filaments on ac would not degrade the spectrum to where it would be detrimental to the radiated RF.

  18. Measuring and communicating blood loss during obstetric hemorrhage.

    PubMed

    Gabel, Kristi T; Weeber, Tracy A

    2012-01-01

    Accurate quantification of blood loss is an essential skill necessary to prevent maternal morbidity and mortality associated with obstetric hemorrhage. Visual estimation of blood has been consistently shown to be extremely inaccurate. The nurse plays a pivotal role in quantifying blood loss after birth, recognizing triggers, mobilizing needed interventions, and providing essential communication. PMID:22548283

  19. Effective Identification of Functional Hearing Loss Using Behavioral Threshold Measures

    ERIC Educational Resources Information Center

    Schlauch, Robert S.; Koerner, Tess K.; Marshall, Lynne

    2015-01-01

    Purpose: Four functional hearing loss protocols were evaluated. Method: For each protocol, 30 participants feigned a hearing loss first on an audiogram and then for a screening test that began a threshold search from extreme levels (-10 or 90 dB HL). Two-tone and 3-tone protocols compared thresholds for ascending and descending tones for 2 (0.5…

  20. 49 CFR 1005.7 - Weight as a measure of loss.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 8 2013-10-01 2013-10-01 false Weight as a measure of loss. 1005.7 Section 1005.7... VOLUNTARY DISPOSITION OF LOSS AND DAMAGE CLAIMS AND PROCESSING SALVAGE § 1005.7 Weight as a measure of loss. Where weight is used as a measure of loss in rail transit of scrap iron and steel and actual tare...

  1. 49 CFR 1005.7 - Weight as a measure of loss.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Weight as a measure of loss. 1005.7 Section 1005.7... VOLUNTARY DISPOSITION OF LOSS AND DAMAGE CLAIMS AND PROCESSING SALVAGE § 1005.7 Weight as a measure of loss. Where weight is used as a measure of loss in rail transit of scrap iron and steel and actual tare...

  2. 49 CFR 1005.7 - Weight as a measure of loss.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 8 2011-10-01 2011-10-01 false Weight as a measure of loss. 1005.7 Section 1005.7... VOLUNTARY DISPOSITION OF LOSS AND DAMAGE CLAIMS AND PROCESSING SALVAGE § 1005.7 Weight as a measure of loss. Where weight is used as a measure of loss in rail transit of scrap iron and steel and actual tare...

  3. 49 CFR 1005.7 - Weight as a measure of loss.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 8 2014-10-01 2014-10-01 false Weight as a measure of loss. 1005.7 Section 1005.7... VOLUNTARY DISPOSITION OF LOSS AND DAMAGE CLAIMS AND PROCESSING SALVAGE § 1005.7 Weight as a measure of loss. Where weight is used as a measure of loss in rail transit of scrap iron and steel and actual tare...

  4. 49 CFR 1005.7 - Weight as a measure of loss.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 8 2012-10-01 2012-10-01 false Weight as a measure of loss. 1005.7 Section 1005.7... VOLUNTARY DISPOSITION OF LOSS AND DAMAGE CLAIMS AND PROCESSING SALVAGE § 1005.7 Weight as a measure of loss. Where weight is used as a measure of loss in rail transit of scrap iron and steel and actual tare...

  5. High-Resolution ac Measurements of the Hall Effect in Organic Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Yi, H. T.; Podzorov, V.

    2016-03-01

    We describe a high resolving power technique for Hall-effect measurements, efficient in determining Hall mobility and carrier density in organic field-effect transistors and other low-mobility systems. We utilize a small low-frequency ac magnetic field (Brms<0.25 T ) and a phase-sensitive (lock-in) detection of Hall voltage, with the necessary corrections for Faraday induction. This method significantly enhances the signal-to-noise ratio and eliminates the necessity of using high magnetic fields in Hall-effect studies. With the help of this method, we are able to obtain the Hall mobility and carrier density in organic transistors with a mobility as low as μ ˜0.3 cm2 V-1 s-1 by using a compact desktop apparatus and low magnetic fields. We find a good agreement between Hall-effect and electric-field-effect measurements, indicating that, contrary to the common belief, certain organic semiconductors with mobilities below 1 cm2 V-1 s-1 can still exhibit a fully developed, band-semiconductor-like Hall effect, with the Hall mobility and carrier density matching those obtained in longitudinal transistor measurements. This suggests that, even when μ <1 cm2 V-1 s-1 , charges in organic semiconductors can still behave as delocalized coherent carriers. This technique paves the way to ubiquitous Hall-effect studies in a wide range of low-mobility materials and devices, where it is typically very difficult to resolve the Hall effect even in very high dc magnetic fields.

  6. 40 CFR 1066.930 - Equipment for point-source measurement of running losses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-source measurement of running losses. For point-source measurement of running loss emissions, use equipment meeting the specifications in 40 CFR 86.107-96(i) Evaporative and Refueling Emission Test... of running losses. 1066.930 Section 1066.930 Protection of Environment ENVIRONMENTAL...

  7. Use of an advanced composite material in construction of a high pressure cell for magnetic ac susceptibility measurements

    NASA Astrophysics Data System (ADS)

    Wang, X.; Misek, M.; Jacobsen, M. K.; Kamenev, K. V.

    2014-10-01

    The applicability of fibre-reinforced polymers for fabrication of high pressure cells was assessed using finite element analysis and experimental testing. Performance and failure modes for the key components of the cell working in tension and in compression were evaluated and the ways for optimising the designs were established. These models were used in construction of a miniature fully non-metallic diamond anvil cell for magnetic ac susceptibility measurements in a magnetic property measurement system. The cell is approximately 14 mm long, 8.5 mm in diameter and was demonstrated to reach a pressure of 5.6 GPa. AC susceptibility data collected on Dy2O3 demonstrate the performance of the cell in magnetic property measurements and confirm that there is no screening of the sample by the environment which typically accompanies the use of conventional metallic high pressure cells in oscillating magnetic fields.

  8. Modeling of the interleaved hysteresis loop in the measurements of rotational core losses

    NASA Astrophysics Data System (ADS)

    Alatawneh, Natheer; Pillay, Pragasen

    2016-01-01

    The measurement of core losses in machine laminations reveals a fundamental difference between rotational and pulsating types. Rotational core losses under rotating fields decrease at high flux density, while pulsating losses keep increasing steadily. Experimental analyses of loss components Px and Py in x and y directions with rotating fields show that the loss decreases in one loss component and sometimes attains negative values. Tracking the evolution of hysteresis loops along this loss component discloses a peculiar behavior of magnetic hysteresis, where the loop changes its path from counterclockwise to clockwise within a cycle of magnetization process, the so called interleaved hysteresis loop. This paper highlights a successful procedure for modeling the interleaved hysteresis loop in the measurement of rotational core losses in electrical machine laminations using the generalized Prandtl-Ishlinskii (PI) model. The efficiency of the proposed model is compared to Preisach model. Results and conclusion of this work are of importance toward building an accurate model of rotational core losses.

  9. Improved direct measurement of A(b) and A(c) at the Z(0) pole using a lepton tag.

    PubMed

    Abe, Kenji; Abe, Koya; Abe, T; Adam, I; Akimoto, H; Aston, D; Baird, K G; Baltay, C; Band, H R; Barklow, T L; Bauer, J M; Bellodi, G; Berger, R; Blaylock, G; Bogart, J R; Bower, G R; Brau, J E; Breidenbach, M; Bugg, W M; Burke, D; Burnett, T H; Burrows, P N; Calcaterra, A; Cassell, R; Chou, A; Cohn, H O; Coller, J A; Convery, M R; Cook, V; Cowan, R F; Crawford, G; Damerell, C J S; Daoudi, M; de Groot, N; de Sangro, R; Dong, D N; Doser, M; Dubois, R; Erofeeva, I; Eschenburg, V; Fahey, S; Falciai, D; Fernandez, J P; Flood, K; Frey, R; Hart, E L; Hasuko, K; Hertzbach, S S; Huffer, M E; Huynh, X; Iwasaki, M; Jackson, D J; Jacques, P; Jaros, J A; Jiang, Z Y; Johnson, A S; Johnson, J R; Kajikawa, R; Kalelkar, M; Kang, H J; Kofler, R R; Kroeger, R S; Langston, M; Leith, D W G; Lia, V; Lin, C; Mancinelli, G; Manly, S; Mantovani, G; Markiewicz, T W; Maruyama, T; McKemey, A K; Messner, R; Moffeit, K C; Moore, T B; Morii, M; Muller, D; Murzin, V; Narita, S; Nauenberg, U; Neal, H; Nesom, G; Oishi, N; Onoprienko, D; Osborne, L S; Panvini, R S; Park, C H; Peruzzi, I; Piccolo, M; Piemontese, L; Plano, R J; Prepost, R; Prescott, C Y; Ratcliff, B N; Reidy, J; Reinertsen, P L; Rochester, L S; Rowson, P C; Russell, J J; Saxton, O H; Schalk, T; Schumm, B A; Schwiening, J; Serbo, V V; Shapiro, G; Sinev, N B; Snyder, J A; Staengle, H; Stahl, A; Stamer, P; Steiner, H; Su, D; Suekane, F; Sugiyama, A; Suzuki, S; Swartz, M; Taylor, F E; Thom, J; Torrence, E; Usher, T; Va'vra, J; Verdier, R; Wagner, D L; Waite, A P; Walston, S; Weidemann, A W; Weiss, E R; Whitaker, J S; Williams, S H; Willocq, S; Wilson, R J; Wisniewski, W J; Wittlin, J L; Woods, M; Wright, T R; Yamamoto, R K; Yashima, J; Yellin, S J; Young, C C; Yuta, H

    2002-04-15

    The parity violation parameters A(b) and A(c) of the Zb(b) and Zc(c) couplings have been measured directly, using the polar angle dependence of the polarized cross sections at the Z(0) pole. Bottom and charmed hadrons were tagged via their semileptonic decays. Both the electron and muon analyses take advantage of new multivariate techniques to increase the analyzing power. Based on the 1993-1998 SLD sample of 550,000 Z(0) decays produced with highly polarized electron beams, we measure A(b) = 0.919+/-0.030(stat)+/-0.024(syst), and A(c) = 0.583+/-0.055(stat)+/-0.055(syst). PMID:11955189

  10. Studies on the activation energy from the ac conductivity measurements of rubber ferrite composites containing manganese zinc ferrite

    NASA Astrophysics Data System (ADS)

    Hashim, Mohd.; Alimuddin; Kumar, Shalendra; Shirsath, Sagar E.; Mohammed, E. M.; Chung, Hanshik; Kumar, Ravi

    2012-11-01

    Manganese zinc ferrites (MZF) have resistivities between 0.01 and 10 Ω m. Making composite materials of ferrites with either natural rubber or plastics will modify the electrical properties of ferrites. The moldability and flexibility of these composites find wide use in industrial and other scientific applications. Mixed ferrites belonging to the series Mn(1-x)ZnxFe2O4 were synthesized for different ‘x’ values in steps of 0.2, and incorporated in natural rubber matrix (RFC). From the dielectric measurements of the ceramic manganese zinc ferrite and rubber ferrite composites, ac conductivity and activation energy were evaluated. A program was developed with the aid of the LabVIEW package to automate the measurements. The ac conductivity of RFC was then correlated with that of the magnetic filler and matrix by a mixture equation which helps to tailor properties of these composites.

  11. Analyzing the Effects of Capacitances-to-Shield in Sample Probes on AC Quantized Hall Resistance Measurements

    PubMed Central

    Cage, M. E.; Jeffery, A.

    1999-01-01

    We analyze the effects of the large capacitances-to-shields existing in all sample probes on measurements of the ac quantized Hall resistance RH. The object of this analysis is to investigate how these capacitances affect the observed frequency dependence of RH. Our goal is to see if there is some way to eliminate or minimize this significant frequency dependence, and thereby realize an intrinsic ac quantized Hall resistance standard. Equivalent electrical circuits are used in this analysis, with circuit components consisting of: capacitances and leakage resistances to the sample probe shields; inductances and resistances of the sample probe leads; quantized Hall resistances, longitudinal resistances, and voltage generators within the quantum Hall effect device; and multiple connections to the device. We derive exact algebraic equations for the measured RH values expressed in terms of the circuit components. Only two circuits (with single-series “offset” and quadruple-series connections) appear to meet our desired goals of measuring both RH and the longitudinal resistance Rx in the same cool-down for both ac and dc currents with a one-standard-deviation uncertainty of 10−8 RH or less. These two circuits will be further considered in a future paper in which the effects of wire-to-wire capacitances are also included in the analysis.

  12. Incorporating residential AC load control into ancillary service markets: Measurement and settlement

    SciTech Connect

    Bode, Josh L.; Sullivan, Michael J.; Berghman, Dries; Eto, Joseph H.

    2013-05-01

    Many pre-existing air conditioner load control programs can provide valuable operational flexibility but have not been incorporated into electricity ancillary service markets or grid operations. Multiple demonstrations have shown that residential air conditioner (AC) response can deliver resources quickly and can provide contingency reserves. A key policy hurdle to be overcome before AC load control can be fully incorporated into markets is how to balance the accuracy, cost, and complexity of methods available for the settlement of load curtailment. Overcoming this hurdle requires a means for assessing the accuracy of shorter-term AC load control demand reduction estimation approaches in an unbiased manner. This paper applies such a method to compare the accuracy of approaches varying in cost and complexity ? including regression analysis, load matching and control group approaches ? using feeder data, household data and AC end-use data. We recommend a practical approach for settlement, relying on an annually updated set of tables, with pre-calculated reduction estimates. These tables allow users to look up the demand reduction per device based on daily maximum temperature, geographic region and hour of day, simplifying settlement and providing a solution to the policy problem presented in this paper.

  13. Bone Loss During Spaceflight: Available Models and Counter-Measures

    NASA Technical Reports Server (NTRS)

    Morris, Jonathan; Bach, David; Geller, David

    2015-01-01

    There is ongoing concern for human health during spaceflights. Of particular interest is the uncoupling of bone remodeling and its resultant effect on calcium metabolism and bone loss. The calculated average loss of bone mineral density (BMD) is approximately 1-1.5% per month of spaceflight. The effect of decreased BMD on associated fractures in astronauts is not known. Currently on the International Space Station (ISS), bone loss is managed through dietary supplements and modifications and resistance exercise regimen. As the duration of space flights increases, a review of the current methods available for the prevention of bone loss is warranted. The goal of this project is to review and summarize recent studies that have focused on maintaining BMD during exposure to microgravity. Interventions were divided into physical (Table 1), nutritional (Table 2), or pharmacologic (Table 3) categories. Physical modalities included resistance exercise, low level vibration, and low intensity pulsed ultrasound. Nutritional interventions included altering protein, salt, and fat intake; and vitamin D supplementation. Pharmacologic interventions included the use of bisphosphonates and beta blockers. Studies reported outcomes based on bone density determined by DXA bone scan, micro-architecture of histology and microCT, and serum and urine markers of bone turnover. The ground analog models utilized to approximate osseous physiology in microgravity included human patients previously paralyzed or subjects confined to bedrest. Ground analog animal models include paralysis, immobilization and ovariectomies. As a result of the extensive research performed there is a multi-modality approach available for the management of BMD during spaceflight that includes resistance training, nutrition and dietary supplements. However, there is a paucity of literature describing a formalized tiered protocol to guide investigators through the progression from animal models to human patient ground

  14. Measurements of DT alpha particle loss near the outer midplane of TFTR

    SciTech Connect

    Zweben, S.J.; Darrow, D.S.; Herrmann, H.W.; Redi, M.H.; Schivell, J.; White, R.B.

    1995-07-01

    Measurements of DT alpha particle loss to the outer midplane region of TFTR have been made using a radially movable scintillator detector. The conclusion from this data is that mechanisms determining the DT alpha loss to the outer midplane are not substantially different from those for DD fusion products. Some of these results are compared with a simplified theoretical model for TF ripple-induced alpha loss, which is expected to be the dominant classical alpha loss mechanism near the outer midplane. An example of plasma-driven MHD-induced alpha particle loss is shown, but no signs of any ``collective`` alpha instability-induced alpha loss have yet been observed.

  15. Measurement of the nuclear energy loss under channeling

    NASA Astrophysics Data System (ADS)

    Winter, H.; Mertens, A.

    2001-07-01

    Neutral Ne atoms with keV energies are scattered under channeling conditions, i.e. at a glancing angle of incidence, from a LiF(001) surface. By means of a time-of-flight method with a pulsed neutral beam we record energy distributions for scattered projectiles. For this specific system the small energy transferred to the crystal lattice ("nuclear energy loss") during channeling via binary collisions with large impact parameters dominates the dissipation of projectile energy. All other excitations of the solid can be brought to a negligible level.

  16. CMP-Neu5Ac Hydroxylase Null Mice as a Model for Studying Metabolic Disorders Caused by the Evolutionary Loss of Neu5Gc in Humans

    PubMed Central

    Kwon, Deug-Nam; Choi, Yun-Jung; Cho, Ssang-Goo; Park, Chankyu; Seo, Han Geuk; Song, Hyuk; Kim, Jin-Hoi

    2015-01-01

    The purpose of this study was to identify the modification/turnover of gene products that are altered in humans due to evolutionary loss of Neu5Gc. CMP-Neu5Ac hydroxylase- (Cmah-) deficient mice show the infiltration of Kupffer cells within liver sinusoids, whereas body and liver weight develop normally. Pathway analysis by use of Illumina MouseRef-8 v2 Expression BeadChip provided evidence that a number of biological pathways, including the glycolysis, gluconeogenesis, TCA cycle, and pentose phosphate pathways, as well as glycogen metabolism-related gene expression, were significantly upregulated in Cmah-null mice. The intracellular glucose supply in Cmah-null mice resulted in mitochondrial dysfunction, oxidative stress, and the advanced glycation end products accumulation that could further induce oxidative stress. Finally, low sirtuin-1 and sirtuin-3 gene expressions due to higher NADH/NAD in Cmah-null mice decreased Foxo-1 and MnSOD gene expression, suggesting that oxidative stress may result in mitochondrial dysfunction in Cmah-null mouse. The present study suggests that mice with CMAH deficiency can be taken as an important model for studying metabolic disorders in humans. PMID:26558285

  17. Nanoscale Electromechanics To Measure Thermal Conductivity, Expansion, and Interfacial Losses.

    PubMed

    Mathew, John P; Patel, Raj; Borah, Abhinandan; Maliakkal, Carina B; Abhilash, T S; Deshmukh, Mandar M

    2015-11-11

    We study the effect of localized Joule heating on the mechanical properties of doubly clamped nanowires under tensile stress. Local heating results in systematic variation of the resonant frequency; these frequency changes result from thermal stresses that depend on temperature dependent thermal conductivity and expansion coefficient. The change in sign of the linear expansion coefficient of InAs is reflected in the resonant response of the system near a bath temperature of 20 K. Using finite element simulations to model the experimentally observed frequency shifts, we show that the thermal conductivity of a nanowire can be approximated in the 10-60 K temperature range by the empirical form κ = bT W/mK, where the value of b for a nanowire was found to be b = 0.035 W/mK(2), significantly lower than bulk values. Also, local heating allows us to independently vary the temperature of the nanowire relative to the clamping points pinned to the bath temperature. We suggest a loss mechanism (dissipation ~10(-4)-10(-5)) originating from the interfacial clamping losses between the metal and the semiconductor nanostructure. PMID:26479952

  18. Neutron Time-of-Flight Measurements of Charged-Particle Energy Loss in Inertial Confinement Fusion Plasmas

    NASA Astrophysics Data System (ADS)

    Sayre, Daniel; Cerjan, Charlie; Berzak Hopkins, Laura; Caggiano, Joseph; Divol, Laurent; Eckart, Mark; Graziani, Frank; Grim, Gary; Hartouni, Ed; Hatarik, Robert; Le Pape, Sebastien; MacKinnon, Andrew; Schneider, Dieter; Sepke, Scott

    2015-11-01

    Neutron time-of-flight measurements of inflight T (d , n) α reactions created during an implosion of a deuterium gas target have been performed at the National Ignition Facility, with order of magnitude improvements in statistics and resolution over past experiments. In the implosion, energetic tritons emitted by thermonuclear fusion within the deuterium plasma produced over 1011 inflight T (d , n) α reactions. The yield and particle spectrum of inflight reactions are sensitive to the triton's energy loss in the plasma, which, in this implosion, consisted of multi-keV temperatures and number densities above 1024 cm-3. Radiation-hydrodynamic simulations of the implosion were adjusted to match the yield and broadening of the D (d , n) 3 He neutron peak. These same simulations give reasonable agreement with the measured T (d , n) α yield and neutron spectrum, and this provides a strong consistency check of the simulated plasma conditions and energy loss model. This research was performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  19. Measuring thermal diffusivity of mechanical and optical grades of polycrystalline diamond using an AC laser calorimetry method

    SciTech Connect

    Rule, Toby D.; Cai, Wei; Wang, Hsin

    2013-01-01

    Because of its extremely high thermal conductivity, measuring the thermal conductivity or diffusivity of optical-grade diamond can be challenging. Various methods have been used to measure the thermal conductivity of thick diamond films. For the purposes of commercial quality control, the AC laser calorimetry method is appealing because it enables fairly rapid and convenient sample preparation and measurement. In this paper, the method is used to measure the thermal diffusivity of optical diamond. It is found that sample dimensions and measurement parameters are critical, and data analysis must be performed with great care. The results suggest that the method as it is applied to optical-grade diamond could be enhanced by a more powerful laser, higher frequency beam modulation, and post-processing based on 2D thermal simulation.

  20. Size-Dependent Relaxation Properties of Monodisperse Magnetite Nanoparticles Measured Over Seven Decades of Frequency by AC Susceptometry.

    PubMed

    Ferguson, R Matthew; Khandhar, Amit P; Jonasson, Christian; Blomgren, Jakob; Johansson, Christer; Krishnan, Kannan M

    2013-07-01

    Magnetic relaxation is exploited in innovative biomedical applications of magnetic particles such as magnetic particle imaging (MPI), magnetic fluid hyperthermia, and bio-sensing. Relaxation behavior should be optimized to achieve high performance imaging, efficient heating, and good SNR in bio-sensing. Using two AC susceptometers with overlapping frequency ranges, we have measured the relaxation behavior of a series of monodisperse magnetic particles and demonstrated that this approach is an effective way to probe particle relaxation characteristics from a few Hz to 10 MHz, the frequencies relevant for MPI, hyperthermia, and sensing. PMID:25473124

  1. Field measurements of water and nitrogen losses under irrigated maize

    NASA Astrophysics Data System (ADS)

    Kengni, L.; Vachaud, G.; Thony, J. L.; Laty, R.; Garino, B.; Casabianca, H.; Jame, P.; Viscogliosi, R.

    1994-10-01

    An intensive multidisciplinary experiment has been conducted over several years at La Côte Saint-André, near Grenoble, France. The major objective is to determine an optimal fertilizer application scheme for an irrigated agricultural system. Such a scheme would not degrade the quality of the environment, and yet would maintain a profitable level of crop production. This study is explicitly related to the cultivation of irrigated maize, a major crop in the area. The various terms of the water balance (consumption, drainage, soil storage) and of the nitrogen cycle (mineralization, plant uptake, leaching) were obtained from intensive monitoring in the upper layer of the 0.8 m of soil which corresponds to the root zone of the crop. This entailed the combined use of a neutron moisture meter, tensiometers and soil suction cups. To determine the specific effects of fertilization and crop growth, there were different treatments. These corresponded to a traditional fertilizer application of 260 kg N ha -1, no fertilization, and bare soil, carried out within an area of approximately 2 ha. Several sites were instrumented on each treatment, one of them being specifically for the application and the monitoring of 15N-tagged fertilizer. The results have shown that, in terms of the water balance, irrigation water management is extremely efficient, as drainage losses under the maize culture are negligible during the crop cycle. The situation is totally different, however, during the intercrop period (October-April), owing to rainfall. Then the soil is left bare and evaporation is very small, and now the drainage corresponds to about 90% of total inputs from precipitation. In terms of the nitrogen cycle, the results showed clearly that up to 150 kg N ha -1 was produced by mineralization in the soil. Nitrogen leaching beyond the root zone during the crop cycle is negligible, regardless of the rate of fertilizer application, as a result of the very small amount of drainage, despite

  2. Experimental measurement and calculation of losses in planar radial magnetic bearings

    NASA Technical Reports Server (NTRS)

    Kasarda, M. E. F.; Allaire, P. E.; Hope, R. W.; Humphris, R. R.

    1994-01-01

    The loss mechanisms associated with magnetic bearings have yet to be adequately characterized or modeled analytically and thus pose a problem for the designer of magnetic bearings. This problem is particularly important for aerospace applications where low power consumption of components is critical. Also, losses are expected to be large for high speed operation. The iron losses in magnetic bearings can be divided into eddy current losses and hysteresis losses. While theoretical models for these losses exist for transformer and electric motor applications, they have not been verified for magnetic bearings. This paper presents the results from a low speed experimental test rig and compares them to calculated values from existing theory. Experimental data was taken over a range of 90 to 2,800 rpm for several bias currents and two different pole configurations. With certain assumptions agreement between measured and calculated power losses was within 16 percent for a number of test configurations.

  3. Physical and electrical models for interpreting AC and DC transport measurements in polymer solar cells

    NASA Astrophysics Data System (ADS)

    McIntyre, Max; Tzolov, Marian; Cossel, Raquel; Peeler, Seth

    We have fabricated and studied bulk heterojunction solar cells using a mixture of the low bandgap material PCPDTBT and PCBM-C60. Our transport studies show that the devices in dark have good rectification and they respond to AC voltage as a simple RC circuit. The illumination causes an additional contribution to the impedance, which varies with the level of illumination. One proposed model is that photo-generated charges can become trapped in potential wells. These charges then follow a Debye relaxation process, which contributes to a varying dielectric constant. Another proposed model is based on a RC circuit model with two capacitors which can describe the varying capacitance behavior. The physical mechanism for this model is that photo-generated charges become accumulated at the interface between PCPDTBT and PCBM-C60 and form an additional layer of charge. We will show that our circuit models and their analogous physical models can predict the AC and DC responses of polymer solar cells.

  4. Correcting thermocouple measurements for radiation loss: A critical review

    SciTech Connect

    Shaddix, C.R.

    1999-07-01

    Thermocouples are one of the simplest and most ubiquitous experimental diagnostics in combustion research and high-temperature process flows. However, quantitative interpretation of thermocouple measurements in high-temperature environments is hampered by the need to account for important heat transfer mechanisms associated with the thermocouple wire and junction, especially thermal radiation. A number of assumptions and simplifications are of necessity incorporated in applying a radiation-correction to a thermocouple measurement, but the assumptions made in different investigations have often been poorly-documented or are inconsistent with the relevant literature guidance. This paper reviews the considerations in performing an energy balance on practical thermocouple junctions and assesses the best available information regarding the appropriate choices to make in performing radiation corrections. In particular, the effects of Nusselt number correlation, thermocouple wire and junction size, the local gas mixture transport properties, and the thermocouple emissivity are explored. The magnitude of the calculated radiation correction for different assumed values of the relevant variables is illustrated.

  5. Simultaneous ac and dc magnetic field measurements in residential areas: Implications for resonance theories of biological effects

    SciTech Connect

    Wong, P.S.; Sastre, A.

    1995-10-01

    The goal of this study was to obtain data that could be used to evaluate the applicability of ``resonance`` theories of biological effects in residential settings. The authors first describe a measurement system which allows the study of ac and dc magnetic fields simultaneously in space and in time. Sample measurements were taken near two power lines, two objects and in two residential homes. The results show that the earth`s (dc) magnetic field was unaffected near power lines. The compass orientation of the power line influenced the relative values of the ac components parallel and perpendicular to the dc field. The electric heating system greatly affected the ac field levels in the home, causing the levels to increase from less than 1 mG to a maximum of 7.5 mG during heating. The magnitudes of the dc field in the two homes varied from about 380 to 650 mG, with the larger variations near metallic or magnetic objects such as the refrigerator or a metallic air duct. The earth`s field was elevated above its natural level within a distance of 8 feet from a subcompact passenger car, e.g., the level changed from about 540 to 1,100 mG beside the headlight. A steel chair changed the earth`s field by up to 60 mG within a distance of one foot. These results suggest that some of the narrow ``resonances`` described in laboratory studies may be difficult to observe against the variations in do field amplitude and direction resulting from the presence of everyday metallic objects.

  6. Periotest for measuring periodontal characteristics--correlation with periodontal bone loss.

    PubMed

    Schulte, W; d'Hoedt, B; Lukas, D; Maunz, M; Steppeler, M

    1992-05-01

    The Periotest measures the reaction of the periodontium to a defined percussive force. The percussion is applied to the tooth by an electronically controlled tapping head. Information on structural change is obtained by measurement of both the elastic and viscous characteristics of the periodontium. The latter prevent oscillations of the tooth in the alveolar bone. A value is calculated and is displayed as a "Periotest value". The following research report shows the relation of Periotest values to bone loss. Bone loss was quantitatively determined for 2312 teeth from orthopantomographic radiographs and for 900 teeth exposed to intra-oral films using the standard paralleling technique. A differentiation was made between vertical and horizontal bone loss. Clinical mobility index, pocket depth, gingival recession and papillary hemorrhagic index were also measured. There was a strong association between the Periotest value and bone loss. These results suggest that Periotest evaluation provides an objective indication of the extent of periodontal bone loss. PMID:1608031

  7. Measurements of Electron Temperature and Density, in an AC Pulsed Oxygen Plasma Discharge

    NASA Astrophysics Data System (ADS)

    Yousif, Farook; Martinez, Horacio; Castillo, Fermin

    2007-06-01

    Emission and analytical spectroscopy was applied to investigate O2 plasma, which was generated by an AC discharge between 0.15 and 0.5 Torr pressure. For the diagnostic study, a double Langmuir probe was employed. The derivation of plasma parameters is based on a theoretical description of the double-probe current-voltage characterization in the Thick Sheath Limit (TSL) region [1]. Electron temperature of Te = 1.09 eV and an ion density of ni= 2.08 x 10^10 cm-3 were evaluated at 2 Torr. We present electron temperature and ion density as a function of the pressure at 3 different power discharge levels. Also we present emission spectroscopy in the wavelength range of 200-1100 nm as a function of the pressure. [1] J.D. Swift and J. R. Schwar, Electric Probes for Plasma Diagnostics (New York: Elsevier) 1971.

  8. Electrical Effect in Silver-Point Realization Due to Cell Structure and Bias Voltage Based on Resistance Measurement Using AC and DC Bridges

    NASA Astrophysics Data System (ADS)

    Widiatmo, J. V.; Harada, K.; Yamazawa, K.; Tamba, J.; Arai, M.

    2015-08-01

    Electrical effects related to insulating leakage represent one of the major factors contributing to uncertainties in measurements using high-temperature standard platinum resistance thermometers (HTSPRTs), especially during the realization of the silver freezing point (). This work is focused on the evaluation of the differences in resistance measurements observed when using AC resistance bridges and DC resistance bridges, hereafter, termed the AC-DC differences, as the result of various electrical effects. The magnitude of the AC-DC difference in several silver-point cells is demonstrated with several HTSPRTs. The effect of the cell structure on the AC-DC difference is evaluated by exchanging some components, part by part, within a silver-point cell. Then, the effect of the bias voltage applied to the heat pipe within the silver-point furnace is evaluated. Through the analysis of the experimental results and comparison with the reports in the literature, the importance of evaluating the AC-DC difference as a means to characterize the underlying electrical effects is discussed, considering that applying a negative bias condition to the furnace with respect to the high-temperature SPRT can minimize the AC-DC difference. Concluding recommendations are proposed on the components used in silver-point cells and the application of a bias voltage to the measurement circuit to minimize the effects of the electrical leakage.

  9. Measurement of the mechanical loss of a cooled reflective coating for gravitational wave detection

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kazuhiro; Miyoki, Shinji; Uchiyama, Takashi; Ishitsuka, Hideki; Ohashi, Masatake; Kuroda, Kazuaki; Tomaru, Takayuki; Sato, Nobuaki; Suzuki, Toshikazu; Haruyama, Tomiyoshi; Yamamoto, Akira; Shintomi, Takakazu; Numata, Kenji; Waseda, Koichi; Ito, Kazuhiko; Watanabe, Koji

    2006-07-01

    We have measured the mechanical loss of a dielectric multilayer reflective coating (ion-beam sputtered SiO2 and Ta2O5) in cooled mirrors. The loss was nearly independent of the temperature (4K˜300K), frequency, optical loss, and stress caused by the coating, and the details of the manufacturing processes. The loss angle was (4˜6)×10-4. The temperature independence of this loss implies that the amplitude of the coating thermal noise, which is a severe limit in any precise measurement, is proportional to the square root of the temperature. Sapphire mirrors at 20 K satisfy the requirement concerning the thermal noise of even future interferometric gravitational wave detector projects on the ground, for example, LCGT.

  10. Scintillator-based diagnostic for fast ion loss measurements on DIII-D.

    PubMed

    Fisher, R K; Pace, D C; García-Muñoz, M; Heidbrink, W W; Muscatello, C M; Van Zeeland, M A; Zhu, Y B

    2010-10-01

    A new scintillator-based fast ion loss detector has been installed on DIII-D with the time response (>100 kHz) needed to study energetic ion losses induced by Alfvén eigenmodes and other MHD instabilities. Based on the design used on ASDEX Upgrade, the diagnostic measures the pitch angle and gyroradius of ion losses based on the position of the ions striking the two-dimensional scintillator. For fast time response measurements, a beam splitter and fiberoptics couple a portion of the scintillator light to a photomultiplier. Reverse orbit following techniques trace the lost ions to their possible origin within the plasma. Initial DIII-D results showing prompt losses and energetic ion loss due to MHD instabilities are discussed. PMID:21033833

  11. Measurement of the complex permittivity of low loss polymer powders in the millimeter-wave range.

    PubMed

    Kapilevich, Boris; Litvak, Boris; Wainstein, Vladimir; Moshe, Danny

    2007-01-01

    An improved measurement method of complex permittivity of low loss polymer powders is suggested. The measurements are done in the mm-wave range using a quasi optical resonator. The 2-D corrugated mode exciter is employed to improve suppression of undesirable higher modes. The model used for reconstructing complex permittivity takes into account ohm losses of metal mesh coupling that provide better accuracy of the reconstructing procedure. An example illustrating this method is reported. PMID:17645209

  12. Nondestructive relative permittivity and loss tangent measurements using a split-cylinder resonator

    NASA Astrophysics Data System (ADS)

    Janezic, Michael Daniel

    To keep pace with the expanding wireless and electronics industries, manufacturers are developing innovative materials for improving system performance, and there is a critical need to accurately characterize the electrical properties of these new materials at microwave frequencies. To address this need, this thesis develops a nondestructive method for measuring the relative permittivity and loss tangent of dielectric substrates using a split-cylinder resonator. Three theoretical models for the split-cylinder resonator are derived using mode-matching, least-squares boundary residual, and Hankel-transform methods, from which one can calculate the relative permittivity and loss tangent of a dielectric substrate from measurements of the split-cylinder resonator's TE0np resonant frequency and quality factor. Each of these models has several advantages over previously published models. First, the accuracy of the relative permittivity measurement is increased because each model accurately models the fringing fields that extend beyond the cylindrical-cavity sections. Second, to increase the accuracy of the loss tangent measurement, each model accurately separates the conductive metal losses of the split-cylinder resonator from the dielectric losses of the substrate. Finally, in contrast to previous models for the split-cylinder resonator that use only the TE011 resonant mode, each of the new models include the higher-order TE0np resonant modes, thereby broadening the frequency range over which one can make relative permittivity and loss tangent measurements. In a comparison of the three models, the mode-matching method was found to be superior on the basis of measurement accuracy and computational speed. Relative permittivity and loss tangent measurements for several dielectric materials are performed using a split-cylinder resonator and are in good agreement with measurements made using a circular-cylindrical cavity, split-post resonator, and dielectric post resonator

  13. Measurement of dielectric loss tangent at cryogenic temperature using superconducting film resonator

    NASA Astrophysics Data System (ADS)

    Zhang, Yufang; Wang, Zhenqing

    2016-03-01

    We demonstrate that the superconducting film resonator can be used to accurately and quantitatively measure the microwave dielectric loss tangent of a variety of materials. Compared to traditional dielectric resonator loaded metal cavity method, it has advantage of small sample size (~2-3 orders of magnitude smaller than the old method), and much higher sensitivity to measure small loss tangent values as small as 10-5 at around 7 GHz band at cryogenic temperatures. This method can be utilized widely in study of mechanism of microwave loss at cryogenic temperature range, which is extremely important in superconducting microwave application areas, such as novel super quantum computers.

  14. Verification of three-microphone impedance tube method for measurement of transmission loss in aerogels

    NASA Astrophysics Data System (ADS)

    Connick, Robert J.

    Accurate measurement of normal incident transmission loss is essential for the acoustic characterization of building materials. In this research, a method of measuring normal incidence sound transmission loss proposed by Salissou et al. as a complement to standard E2611-09 of the American Society for Testing and Materials [Standard Test Method for Measurement of Normal Incidence Sound Transmission of Acoustical Materials Based on the Transfer Matrix Method (American Society for Testing and Materials, New York, 2009)] is verified. Two sam- ples from the original literature are used to verify the method as well as a Filtros RTM sample. Following the verification, several nano-material Aerogel samples are measured.

  15. Relativistic electron loss measurements from the LANL GPS energetic particle instruments.

    NASA Astrophysics Data System (ADS)

    Friedel, R. H.; Koller, J.; Cayton, T. E.; Green, J. C.; O'Brien, T. P.; Onsager, T. G.

    2004-12-01

    In a recent study Green et al. performed a superposed epoch study of 52 relativistic electron loss events as measured by the LANL geosynchronous satellites and posed a basic question: "Where did all the relativistic electrons go?" Their study covered weakly disturbed times (DST>-60) and indicated an initial adiabatic response followed by permanent loss at geosynchronous. Losses as deep as L=4 and no proton losses rule out magnetopause shadowing, leaving precipitation losses due to wave particle interactions as a likely candidate. We use here the dense coverage of the LANL GPS energetic particle instrument constellation to perform a superposed epoch study of the same set of events. The GPS satellites cover the region from L=4 outward every three hours. Using two inter-calibrated GPS satellites (ns24 and ns33) enables us to achieve both a high time resolution on the L=dependent loss timescales. Initial results indicate that for higher L and lower energies (L ˜ 5-6, E ˜ 300 KeV) losses occur quickly over a period of 3-9 hours, while at lower L (L ˜ 4) and higher energies (E ˜ 2 MeV) the rates are longer, 8--24 hours. We will attempt to use the local time information from our constellation to identify in which local time regions these losses occur first or are more severe, which will enable us to test some of the current theories for these losses (EMIC or whistler waves?).

  16. In situ glyoxal measurements in rural settings: loss processes, biogenic contribution and model - measurement comparison

    NASA Astrophysics Data System (ADS)

    Huisman, A. J.; Gilman, J. B.; McKay, M.; Lafranchi, B.; Crounse, J. D.; Mielke, L. H.; Mao, J.; Bouvier-Brown, N. C.; Matross, D.; Keutsch, F. N.

    2009-04-01

    concentrations. We will also present a detailed analysis of the BEARPEX 2007 campaign using photochemical box modeling: The results of the model show that the majority of glyoxal observed during that campaign was of biogenic origin and had a short (less than a few hours) lifetime for typical daytime conditions. The observed glyoxal concentrations show a pronounced and highly variable diurnal cycle. An analysis of the individual production and loss processes controlling glyoxal concentrations will be presented along with analysis of the relationship between the observed glyoxal concentrations to biogenic and anthropogenic emissions during BEARPEX 2007. Results of a study exploring the utility of nighttime observations of glyoxal, made possible by the high sensitivity of the Madison LIP instrument, as a tool for analyzing nighttime OH concentrations and uptake of glyoxal onto aerosol as a sink will be presented. This high sensitivity allowed fast measurements which also revealed a pronounced but brief (less than 15 minute) increase in glyoxal some mornings during BEARPEX 2007 which was not observed during the PROPHET 2008 campaign. This spike was typically observed on days that had a temporally coinciding and similarly brief decrease in ozone concentrations. We will present results of our box model to identify potential processes which explain this feature.

  17. Evaluation of the electrode performance for PAFC by using acid absorption, acceleration and ac-impedance measurement

    SciTech Connect

    Kim, Chang-Soo; Song, Rak-Hyun; Choi, Byung-Woo

    1996-12-31

    In PAFC, the degradation on cathode electrode caused by carbon corrosion, platinum dissolution and growth is especially severe. An acceleration test is a good technique for evaluating the degradation of electrode performance, because it does not need long time. Coleman et al used thermal cycling and on-off cycling as an acceleration test. Song et al showed that hydrogen shortage decreased the electrode performance more rapidly than that of air shortage in gas shortage test. Honji et al reported that the rate of coarsening of Pt particle is rapid in open circuit potential and this is one of major causes on the performance degradation of electrode. The cathode performance has been studied by using acid absorption, acceleration and ac-impedance measurements as functions of the polytetrafluoroethylene (PTFE) contents and sintering temperatures of the electrode.

  18. Use and abuse of the medical loss ratio to measure health plan performance.

    PubMed

    Robinson, J C

    1997-01-01

    This paper examines the use and abuse of the medical loss ratio in the contemporary health care system and health policy debate. It begins with a survey of the ways in which the medical loss ratio has been interpreted to be something it is not, such as a measure of quality or efficiency. It then analyzes key organizational features of the emerging health care system that complicate measures of financial performance, including integration between payers and providers, diversification of payers across multiple products and distribution channels, and geographic expansion across metropolitan and state lines. These issues are illustrated using medical loss ratios from a range of nonprofit and for-profit health plans. The paper then sketches a strategy for improving the public's understanding of health plan performance as an alternative to continued reliance on the flawed medical loss ratio. This strategy incorporates data on structure and process, service quality, and financial performance. PMID:9248162

  19. Thermionic triode generates ac power

    NASA Technical Reports Server (NTRS)

    Kniazzeh, A. G. F.; Scharz, F. C.

    1970-01-01

    Electrostatic grid controls conduction cycle of thermionic diode to convert low dc output voltages to high ac power without undesirable power loss. An ac voltage applied to the grid of this new thermionic triode enables it to convert heat directly into high voltage electrical power.

  20. Precision measurement system and analysis of low core signal loss in DCF couplers

    NASA Astrophysics Data System (ADS)

    Yan, P.; Wang, X. J.; Fu, Ch; Li, D.; Sun, J. Y.; Gong, M. L.; Xiao, Q. R.

    2016-07-01

    In order to achieve higher output power of double cladding fiber lasers, low signal loss has become a focus in researches on optical technology, especially double-clad fiber (DCF) couplers. According to the analysis, DCF couplers with low core signal loss (less than 1%) are produced. To obtain higher precision, we use the first-proposed method for core signal transfer efficiency measurement based on the fiber propagation field image processing. To the best of our knowledge, we report, for the first time, the results of the core signal loss less than 1% in DCF coupler measured by our measurement with high stability and relative precision. The measurement values can assess the quality of DCF couplers and be used as a signal to suggest the improvement on the processing technology of our self-made DCF couplers.

  1. Acid rain and weathering damage to carbonate building stone: Results of material loss measurements

    SciTech Connect

    Reddy, M.; Youngdahl, C.A.

    1987-01-01

    Marble and limestone specimens were exposed to atmospheric conditions at four eastern U.S. sites. A number of methods were employed for damage assessment; this paper describes the results of chemical and physical measurements of material loss. Good agreement was observed among results obtained with different methods. A rate of surface recession near 15 ..mu..m/y was observed for skyward surfaces of marble tested in North Carolina, and comparable results were obtained at the other test sites. Response of the porous limestone was assessed with greater difficulty; a rate of loss similar to that of marble was inferred. Initial correlations of material loss with environmental factors are briefly discussed.

  2. Acid rain and weathering damage to carbonate building stone: Results of material loss measurements

    SciTech Connect

    Reddy, M.M.; Youngdahl, C.A.

    1986-11-01

    Marble and limestone specimens were exposed to atmospheric conditions at four eastern US sites. A number of methods were employed for damage assessment; this paper describes the results of chemical and physical measurements of material loss. Good agreement was observed among results obtained with different methods. A rate of surface recession near 15 ..mu..m/y was observed for skyward surfaces of marble tested in North Carolina, and comparable results were obtained at the other test sites. Response of the porous limestone was assessed with greater difficulty; a rate of loss similar to that of marble was inferred. Initial correlations of material loss with environmental factors are briefly discussed.

  3. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  4. Cryogenic measurements of mechanical loss of high-reflectivity coating and estimation of thermal noise.

    PubMed

    Granata, Massimo; Craig, Kieran; Cagnoli, Gianpietro; Carcy, Cécile; Cunningham, William; Degallaix, Jérôme; Flaminio, Raffaele; Forest, Danièle; Hart, Martin; Hennig, Jan-Simon; Hough, James; MacLaren, Ian; Martin, Iain William; Michel, Christophe; Morgado, Nazario; Otmani, Salim; Pinard, Laurent; Rowan, Sheila

    2013-12-15

    We report on low-frequency measurements of the mechanical loss of a high-quality (transmissivity T<5 ppm at λ(0)=1064 nm, absorption loss <0.5 ppm) multilayer dielectric coating of ion-beam-sputtered fused silica and titanium-doped tantala in the 10-300 K temperature range. A useful parameter for the computation of coating thermal noise on different substrates is derived as a function of temperature and frequency. PMID:24322234

  5. Fabrication and THz loss measurements of porous subwavelength fibers using a directional coupler method.

    PubMed

    Dupuis, Alexandre; Allard, Jean-François; Morris, Denis; Stoeffler, Karen; Dubois, Charles; Skorobogatiy, Maksim

    2009-05-11

    We report several strategies for the fabrication of porous subwavelength fibers using low density Polyethylene plastic for low-loss terahertz light transmission applications. We also characterize transmission losses of the fabricated fibers in terahertz using a novel non-destructive directional coupler method. Within this method a second fiber is translated along the length of the test fiber to probe the power attenuation of a guided mode. The method is especially suitable for measuring transmission losses through short fiber segments, a situation in which standard cutback method is especially difficult to perform. We demonstrate experimentally that introduction of porosity into a subwavelength rod fiber, further reduces its transmission loss by as much as a factor of 10. The lowest fiber loss measured in this work is 0.01 cm(-1) and it is exhibited by the 40% porous subwavelength fiber of diameter 380 microm. For comparison, the loss of a rod-in-the-air subwavelength fiber of a similar diameter was measured to be approximately 0.1 cm(-1), while the bulk loss of a PE plastic used in the fabrication of such fibers is >or= 1 cm(-1). Finally, we present theoretical studies of the optical properties of individual subwavelength fibers and a directional coupler. From these studies we conclude that coupler setup studied in this paper also acts as a low pass filter with a cutoff frequency around 0.3 THz. Considering that the spectrum of a terahertz source used in this work falls off rapidly below 0.25 THz, the reported loss measurements are, thus, the bolometer averages over the approximately 0.25 THz-0.3 THz region. PMID:19434133

  6. A slowly rotating coil system for AC field measurements of Fermilab booster correctors

    SciTech Connect

    Velev, G.; DiMarco, J.; Harding, David J.; Kashikhin, V.; Lamm, Michael J.; Schlabach, P.; Tartaglia, Michael Albert; Tompkins, John C.; /Fermilab

    2007-06-01

    A method for measurement of rapidly changing magnetic fields has been developed and applied to the testing of new room temperature corrector packages designed for the Fermilab Booster Synchrotron. The method is based on fast digitization of a slowly rotating tangential coil probe, with analysis combining the measured coil voltages across a set of successive magnet current cycles. This paper presents results on the field quality measured for the normal and skew dipole, quadrupole, and sextupole elements in several of these corrector packages.

  7. Error in Dasibi flight measurements of atmospheric ozone due to instrument wall-loss

    NASA Technical Reports Server (NTRS)

    Ainsworth, J. E.; Hagemeyer, J. R.; Reed, E. I.

    1981-01-01

    Theory suggests that in laminar flow the percent loss of a trace constituent to the walls of a measuring instrument varies as P to the -2/3, where P is the total gas pressure. Preliminary laboratory ozone wall-loss measurements confirm this P to the -2/3 dependence. Accurate assessment of wall-loss is thus of particular importance for those balloon-borne instruments utilizing laminar flow at ambient pressure, since the ambient pressure decreases by a factor of 350 during ascent to 40 km. Measurements and extrapolations made for a Dasibi ozone monitor modified for balloon flight indicate that the wall-loss error at 40 km was between 6 and 30 percent and that the wall-loss error in the derived total ozone column-content for the region from the surface to 40 km altitude was between 2 and 10 percent. At 1000 mb, turbulence caused an order of magnitude increase in the Dasibi wall-loss.

  8. Annual bone loss and success rates of dental implants based on radiographic measurements

    PubMed Central

    Zhang, L; Liu, Y; Wismeijer, D

    2014-01-01

    Objectives: Bone loss around dental implants is generally measured by monitoring changes in marginal bone level using radiographs. After the first year of implantation, an implant should have <0.2 mm annual loss of marginal bone level to satisfy the criteria of success. However, the process of measuring marginal bone level on radiographs has a precision of 0.2 mm (or more) owing to variations in exposure geometry, exposure time and observer perception. Therefore, the value of the annual loss may vary considerably, especially when short intervals are considered. This study investigates how the success rate of dental implants depends on the way annual bone loss is calculated. Methods: Panoramic radiographs of 82 implant patients with an average follow-up of 10.4 years were analysed. Marginal bone levels near the implants were indicated by one observer. The annual loss of marginal bone level was determined according to four different calculation methods. Results: The methods yielded success rates of 9%, 45%, 81% and 89%. Conclusions: The success rate of dental implants measured on radiographs greatly depends on the details of the calculation method. Without rigorous standardization, annual bone loss and implant success rate are not well defined. PMID:25030551

  9. Improved Correction of IR Loss in Diffuse Shortwave Measurements: An ARM Value-Added Product

    SciTech Connect

    Younkin, K; Long, CN

    2003-11-01

    Simple single black detector pyranometers, such as the Eppley Precision Spectral Pyranometer (PSP) used by the Atmospheric Radiation Measurement (ARM) Program, are known to lose energy via infrared (IR) emission to the sky. This is especially a problem when making clear-sky diffuse shortwave (SW) measurements, which are inherently of low magnitude and suffer the greatest IR loss. Dutton et al. (2001) proposed a technique using information from collocated pyrgeometers to help compensate for this IR loss. The technique uses an empirically derived relationship between the pyrgeometer detector data (and alternatively the detector data plus the difference between the pyrgeometer case and dome temperatures) and the nighttime pyranometer IR loss data. This relationship is then used to apply a correction to the diffuse SW data during daylight hours. We developed an ARM value-added product (VAP) called the SW DIFF CORR 1DUTT VAP to apply the Dutton et al. correction technique to ARM PSP diffuse SW measurements.

  10. Measurement of ruby laser cavity losses by Fabry-Perot resonance.

    PubMed

    Nelson, D F; Rodgers, K F

    1967-03-01

    Determinations of optical loss in unpumped ruby laser crystals from measurements of the transmissivity vs optical path length (as changed by temperature) using an amplitude regulated, single mode, He-Ne laser beam probe are described. Excellent agreement between these measurements and the theory of Dufour and Picca was obtained for a flux-grown ruby using as-grown feedback surfaces. The essentially zero loss per pass beta (apart from end reflector losses) deduced from this comparison is in excellent agreement with a previous determination of the loss in this crystal from laser threshold measurements. The reduction of the effective surface roughness by deposition of multilayer zinc sulfide-cryolite reflectors was observed in these experiments. For a high quality, 7.5-cm long, 0.05 wt% Cr(2)O(3), 60 degrees orientation ruby rod, beta was found to be 0.03 +/- 0.03. For a 90 degrees orientation, 2.2-cm long, trumpet-shaped ruby used for continuous operation threshold studies, beta was found to be about 0.14. The problems of this type of loss measurement when index of refraction variations are present are discussed, and observations connecting the crystal quality and laser mode characteristics are presented. PMID:20057771

  11. SOI waveguide fabrication process development using star coupler scattering loss measurements

    NASA Astrophysics Data System (ADS)

    Yap, K. P.; Lapointe, J.; Lamontagne, B.; Delâge, A.; Bogdanov, A.; Janz, S.; Syrett, B.

    2007-12-01

    We show that integrated optical star couplers can be useful characterization devices to measure the sidewall roughness-induced scattering losses of planar waveguides. We describe the detailed fabrication processes of these star couplers on the silicon-on-insulator (SOI) platform and the process improvements implemented to reduce the waveguide sidewall roughness and scattering loss. We report the main process challenges, particularly to assure a clear gap between any adjacent waveguides of the dense and closely spaced output waveguide array. These challenges are addressed by optimizing the exposure dose of the resist and adding an oxygen ashing treatment to eliminate waveguide footings. We demonstrate further improvement on the waveguide profile and sidewall roughness through the use of a thin Cr hardmask for the dry plasma etching. This optimized fabrication process is capable of producing approximately a 3 nm root-mean-square sidewall roughness, measured using both scanning electron microscopy (SEM) and atomic force microscopy (AFM). Using the fabricated star couplers, we manage to measure the relative scattering losses of various waveguides with the width varying from 0.2 to 2.0 μm in a single measurement, and show that the measured losses agree with the measured sidewall roughness.

  12. Measurement of loss of DT fusion products using scintillator detectors in TFTR

    SciTech Connect

    Darrow, D.S.; Herrmann, H.W.; Johnson, D.W.; Marsala, R.J.; Palladino, R.W.; Zweben, S.J.; Tuszewski, M.

    1995-03-01

    A poloidal array of MeV ion loss probes previously used to measure DD fusion product loss has been upgraded to measure the loss of alpha particles from DT plasmas in TFTR. The following improvements to the system have been made in preparation for the use of tritium in TFTR: (1) relocation of detectors to a neutronshielded enclosure in the basement to reduce neutron-induced background signals; (2) replacement of ZnS:Cu (P31) scintillators in the probes with the Y{sub 3}Al{sub 5}0{sub 12}:Ce(P46) variety to minimize damage and assure linearity at the fluxes anticipated from DT plasmas; and (3) shielding of the fiber optic bundles which carry the fight from the probes to the detectors to reduce neutron- and gamma-induced light within them. In addition to the above preparations, the probes have been absolutely calibrated for alpha particles by using the Van de Graaf accelerator at Los Alamos National Laboratory. Alpha particle losses from DT plasmas have been observed, and losses at the detector 901 below the midplane are consistent with first orbit loss.

  13. Effects of production and loss of electrons on HF Doppler radar measurements of vertical plasma drifts

    NASA Astrophysics Data System (ADS)

    Jaya, A. S.; Nayar, S. R. P.; Rao, P. B.

    1993-04-01

    The measurements of vertical plasma drifts at magnetic equator using HF Doppler radar include contributions due to production and loss of electrons and also due to the equatorial electric field. From the computation of the electron density profiles, the temporal variation of electron density changes has been studied and the contribution of production and loss of electrons to the vertical plasma drift measurements using HF Doppler radar during daytime has been evaluated. The evaluation of vertical drifts has been made for different conditions of the ionosphere and for different zenith angles.

  14. AC field measurements of Fermilab Booster correctors using a rotating coil system

    SciTech Connect

    Velev, G.V.; DiMarco, J.; Harding, D.J.; Kashikhin, V.; Lamm, M.; Makulski, A.; Orris, D.; Schlabach, P.; Sylvester, C.; Tartaglia, M.; Tompkins, J.; /Fermilab

    2006-07-01

    The first prototype of a new corrector package for the Fermilab Booster Synchrotron is presently in production. This water-cooled package includes normal and skew dipole, quadrupole and sextupole elements to control orbit, tune and chromaticity of the beam over the full range of Booster energies (0.4-8 GeV). These correctors operate at the 15 Hz excitation cycle of the main synchrotron magnets, but must also make more rapid excursions, in some cases even switching polarity in approximately 1 ms at transition crossing. To measure the dynamic field changes during operation, a new method based on a relatively slow rotating coil system is proposed. The method pieces together the measured voltages from successive current cycles to reconstruct the field harmonics. This paper describes the method and presents initial field quality measurements from a Tevatron corrector.

  15. Identification of boundaries in the cometary environment from AC electric field measurements

    NASA Astrophysics Data System (ADS)

    Mogilevsky, M.; Mikhailov, Y.; Molchanov, O.; Grard, R.; Pedersen, A.; Trotignon, J. G.; Beghin, C.; Formisano, V.; Shapiro, V.; Shevchenko, V.

    1986-12-01

    Electric fields are measured with the AVP-V experiment in the frequency range 8 Hz - 300 kHz. The field amplitude increases significantly, first at a distance of 2×105km, then at distances of 1.2 - 1.5×105km, and 5 - 7×104km from the nucleus. These phenomena have been observed both on VEGA-1 and VEGA-2. The electric field measurements are compared with data obtained from dust and plasma experiments; possible mechanisms responsible for the existence of these boundaries are discussed.

  16. COMPARISON BETWEEN INVERTED AND UNPROCESSED DIGITIZED RADIOGRAPHIC IMAGING IN PERIODONTAL BONE LOSS MEASUREMENTS

    PubMed Central

    Scaf, Gulnara; Morihisa, Olívia; Loffredo, Leonor de Castro Monteiro

    2007-01-01

    The advances in digital imaging technology in dentistry have provided an alternative to film-based radiography and have given new options to detect periodontal bone loss. The purpose of this study was to compare inverted and unprocessed digitized radiographic imaging in periodontal bone loss measurements. Thirty-five film-based periapical radiographs of patients suffering from moderate to advanced untreated periodontal bone loss associated to lower premolar and molars was selected from the department files, with 40 bone loss areas. The film-based radiographs were digitized with a flatbed scanner with a transparency and radiograph adapter used for transilluminating the radiograph imaging. Digitization was performed at 600 dpi and in gray scale. The images were digitized using Image Tool software by applying image inversion, that is, transformation of radiopaque structures into radiolucent structures and vice-versa. The digital data were saved as JPEG files. The images were displayed on a 15-inch and 24-bit video monitor under reduced room lighting. One calibrated examiner performed all radiographic measurements, three times, from the cementoenamel junction to the most apical extension of the bone loss, in both types of image (inverted and unprocessed). Brightness and contrast were adjusted according to the examiner's individual demand. Intraclass correlation coefficient was used to compare the measurements from both types of images. The means of radiographic measurements, in mm, for inverted and unprocessed digitized imaging were 6.4485 and 6.3790, respectively. The intraclass correlation coefficient was significant (0.99) The inverted and unprocessed digitized radiographic images were reliable and there was no difference in the diagnostic accuracy between these images regarding periodontal bone loss measurements. PMID:19089186

  17. Atmospheric chemistry suite (ACS): a set of infrared spectrometers for atmospheric measurements on board ExoMars trace gas orbiter

    NASA Astrophysics Data System (ADS)

    Korablev, Oleg; Grigoriev, Alexei V.; Trokhimovsky, Alexander; Ivanov, Yurii S.; Moshkin, Boris; Shakun, Alexei; Dziuban, Ilia; Kalinnikov, Yurii K.; Montmessin, Franck

    2013-09-01

    The ACS package for ExoMars Trace Gas Orbiter is a part of Russian contribution to ExoMars ESA-Roscosmos mission. On the Orbiter it complements NOMAD investigation and is intended to recover in much extent the science lost with the cancellation of NASA MATMOS and EMCS infrared sounders. ACS includes three separate spectrometers, sharing common mechanical, electrical, and thermal interfaces. NIR is a versatile spectrometer for the spectral range of 0.7-1.6 μm with resolving power of ~20000. It is conceived on the principle of RUSALKA/ISS or SOIR/Venus Express experiments combining an echelle spectrometer and an AOTF (Acousto-Optical Tuneable Filter) for order selection. Up to 8 diffraction orders, each 10-20 nm wide can be measured in one sequence record. NIR will be operated principally in nadir, but also in solar occultations, and possibly on the limb. MIR is a high-resolution echelle instrument exclusively dedicated to solar occultation measurements in the range of 2.2-4.4 μm targeting the resolving power of 50000. The order separation is done by means of a steerable grating cross-disperser, allowing instantaneous coverage of up to 300-nm range of the spectrum for one or two records per second. MIR is dedicated to sensitive measurements of trace gases, approaching MATMOS detection thresholds for many species. TIRVIM is a 2- inch double pendulum Fourier-transform spectrometer for the spectral range of 1.7-17 μm with apodized resolution varying from 0.2 to 1.6 cm-1. TIRVIM is primarily dedicated to monitoring of atmospheric temperature and aerosol state in nadir, and would contribute in solar occultation to detection/reducing of upper limits of some components absorbing beyond 4 μm, complementing MIR and NOMAD. Additionally, TIRVIM targets the methane mapping in nadir, using separate detector optimized for 3.3-μm range. The concept of the instrument and in more detail the optical design and the expected parameters of its three parts, channel by channel are

  18. Dual AC Dipole Excitation for the Measurement of Magnetic Multipole Strength from Beam Position Monitor Data

    SciTech Connect

    M. Spata, G.A. Krafft

    2011-09-01

    An experiment was conducted at Jefferson Lab's Continuous Electron Beam Accelerator Facility to develop a technique for characterizing the nonlinear fields of the beam transport system. Two air-core dipole magnets were simultaneously driven at two different frequencies to provide a time-dependent transverse modulation of the electron beam. Fourier decomposition of beam position monitor data was then used to measure the amplitude of these frequencies at different positions along the beamline. For a purely linear transport system one expects to find solely the frequencies that were applied to the dipoles with amplitudes that depend on the phase advance of the lattice. In the presence of nonlinear fields one expects to also find harmonics of the driving frequencies that depend on the order of the nonlinearity. The technique was calibrated using one of the sextupole magnets in a CEBAF beamline and then applied to a dipole to measure the sextupole and octupole strength of the magnet. A comparison is made between the beam-based measurements, results from TOSCA and data from our Magnet Measurement Facility.

  19. Measuring correlations between beam loss and residual radiation in the Fermilab Main Injector

    SciTech Connect

    Brown, Bruce C.; Wu, Guan Hong; /Fermilab

    2010-09-01

    In order to control beam loss for high intensity operation of the Fermilab Main Injector, electronics has been implemented to provide detailed loss measurements using gas-filled ionization monitors. Software to enhance routine operation and studies has been developed and losses are logged for each acceleration cycle. A systematic study of residual radiation at selected locations in the accelerator tunnel have been carried out by logging residual radiation at each of 142 bar-coded locations. We report on fits of the residual radiation measurements to half-life weighted sums of the beam loss data using a few characteristic lifetimes. The data are now available over a multi-year period including residual radiation measurements repeated multiple times during three extended facility shutdown periods. Measurement intervals of a few weeks combined with variable delays between beam off time and the residual measurement permits sensitivity to lifetimes from hours to years. The results allow planning for work in radiation areas to be based on calibrated analytic models.

  20. RHIC AC DIPOLE DESIGN AND CONSTRUCTION.

    SciTech Connect

    BAI,M.; METH,M.; PAI,C.; PARKER,B.; PEGGS,S.; ROSER,T.; SANDERS,R.; TRBOJEVIC,D.; ZALTSMAN,A.

    2001-06-18

    Two ac dipoles with vertical and horizontal magnetic field have been proposed at RHIC for applications in linear and non-linear beam dynamics and spin manipulations. A magnetic field amplitude of 380 Gm is required to produce a coherent oscillation of 5 times the rms beam size at the top energy. We take the ac dipole frequency to be 1.0% of the revolution frequency away from the betatron frequency. To achieve the strong magnetic field with minimum power loss, an air-core magnet with two seven turn winding of low loss Litz wire resonating at 64 kHz is designed. The system is also designed to allow one to connect the two magnet winding in series to resonate at 37 kHz for the spin manipulation. Measurements of a half length prototype magnet are also presented.

  1. A dielectric resonator method of measuring dielectric properties of low loss materials in the microwave region

    NASA Astrophysics Data System (ADS)

    Sheen, Jyh

    2008-05-01

    A technique for the measurement of dielectric properties of low loss and homogeneously isotropic media in the microwave region is studied. The measuring structure is a resonator made up of a cylindrical dielectric rod and conducting plates. The dielectric constants and loss tangents are computed from the resonant frequencies, structure dimensions and unloaded Qs of the TE01δ mode. A simple field model is introduced to analyze this resonator structure. Unlike other simple models, this model does not have the defect of low measurement accuracy of dielectric properties. Important factors affecting the dielectric properties measurements are introduced. Error sources for measurements are also discussed. The measurement accuracy is justified by comparing the results with those of other techniques. In addition, various methods for calculating the power factor and conducting loss and for measuring the conductivity of the conducting plates are discussed. The accuracies of certain of these methods have not previously been studied, but are given in this paper. The swept frequency capability was also studied. It was found that dielectric properties in microwave frequencies could be measured within a frequency range of 3 GHz.

  2. Loss rate of NO y from a power plant plume based on aircraft measurements

    NASA Astrophysics Data System (ADS)

    Gillani, N. V.; Luria, M.; Valente, R. J.; Tanner, R. L.; Imhoff, R. E.; Meagher, J. F.

    1998-09-01

    This study was motivated by the recent work of Buhr et al. [1996] which reported losses of NOy from large power plant plumes as high as 0.25 hour-1, much higher than generally accepted values. If true, conclusions pertaining to the efficiency of ozone and nitrate production in the lower troposphere would need major revisions. The results of Buhr et al. were based on aircraft measurements in four TVA (Tennessee Valley Authority) power plant plumes on July 7, 1995, as part of the Nashville/Middle Tennessee Ozone Study, a measurement program of the Southern Oxidants Study (SOS), whereas the results reported in this paper are also based on measurements made in the same SOS study aboard another instrumented aircraft (the TVA helicopter), in plumes of one of these power plants (the Cumberland Steam Plant in northwestern Tennessee) during five different days in 1994 and 1995. Between the 1994 and 1995 sampling periods, emissions of SO2 at the Cumberland plant were reduced by nearly 95% by installation of scrubbers. Our data from the one 1994 day show that the ratio of excess SO2 to NOy, in the plume core increased significantly with plume age, indicating a potentially high differential loss rate of NOy (excess loss of NOy relative to SO2) of about 0.12 hour-1. However, results based on the larger 1995 data set indicate a low differential NOy loss rate of only 0.00±0.03 hour-1, consistent with accepted low loss rates. Because the SOS-Nashville/Middle Tennessee Ozone Study was not specifically designed to explore the NOy loss issue, the question of NOy loss rates in plumes is not currently resolved and additional focused field studies are needed.

  3. Performance of a Line Loss Correction Method for Gas Turbine Emission Measurements

    NASA Astrophysics Data System (ADS)

    Hagen, D. E.; Whitefield, P. D.; Lobo, P.

    2015-12-01

    International concern for the environmental impact of jet engine exhaust emissions in the atmosphere has led to increased attention on gas turbine engine emission testing. The Society of Automotive Engineers Aircraft Exhaust Emissions Measurement Committee (E-31) has published an Aerospace Information Report (AIR) 6241 detailing the sampling system for the measurement of non-volatile particulate matter from aircraft engines, and is developing an Aerospace Recommended Practice (ARP) for methodology and system specification. The Missouri University of Science and Technology (MST) Center for Excellence for Aerospace Particulate Emissions Reduction Research has led numerous jet engine exhaust sampling campaigns to characterize emissions at different locations in the expanding exhaust plume. Particle loss, due to various mechanisms, occurs in the sampling train that transports the exhaust sample from the engine exit plane to the measurement instruments. To account for the losses, both the size dependent penetration functions and the size distribution of the emitted particles need to be known. However in the proposed ARP, particle number and mass are measured, but size is not. Here we present a methodology to generate number and mass correction factors for line loss, without using direct size measurement. A lognormal size distribution is used to represent the exhaust aerosol at the engine exit plane and is defined by the measured number and mass at the downstream end of the sample train. The performance of this line loss correction is compared to corrections based on direct size measurements using data taken by MST during numerous engine test campaigns. The experimental uncertainty in these correction factors is estimated. Average differences between the line loss correction method and size based corrections are found to be on the order of 10% for number and 2.5% for mass.

  4. Measuring GAMMA 10 end-loss ions with an ELIS (end-loss-ion spectrometers) from TMX-U

    SciTech Connect

    Foote, J.H.

    1987-09-03

    The author spent the period from March 22 to July 10, 1987, at the GAMMA 10 tandem-mirror experiment at the University of Tsukuba in Tsukuba, Japan. The purpose of this extended trip was to install on GAMMA 10 one of the end-loss-ion spectrometers (ELIS) used on TMX-U (Tandem Mirror Experiment-Upgrade) at LLNL and to make plasma measurements there with this diagnostic instrument. This report discusses the considerable planning and preparations that preceded the trip, the actual experience with the ELIS equipment at GAMMA 10, data and results obtained while the author was there, GAMMA 10 experimental procedures, the scientific and technical support during the stay, and some final comments and suggestions concerning an international exchange such as this one. The data acquired on GAMMA 10 while there, along with earlier data, present an encouraging picture of a plasma in a thermal-barrier mode in a tandem-mirror, magnetic-fusion machine. 6 refs.

  5. A Fast-sampling, Planar Array for Measuring the AC Field of Fermilab Pulsed Extraction Magnets

    SciTech Connect

    DiMarco, E.Joseph; Johnstone, C.; Kiemschies, O.; Kotelnikov, S.K.; Lamm, M.J.; Makulski, A.; Nehring, R.; Orris, D.F.; Russell, A.D.; Tartaglia, Michael Albert; Velev, G.; /Fermilab

    2008-06-25

    A system employing a planar array of inductive pick-up coils has been developed for measurements of the rapidly changing dipole field in pulsed extraction magnets for the Fermilab MuCool project. The magnets are of C-type and deigned to support a peak field of 0.65 T during 8.33 millisecond half-sine pulse at a 15 Hz repetition rate. The coils of the measurement system are fabricated on a single, 97.5 mm wide, 2-layer circuit board. The array of coils is simultaneously sampled at data rates of up to 100 kHz with 10 kHz bandwidth using 24-bit ADC's. A detailed overview of the system and data analysis is presented, along with a characterization of results and system performance.

  6. Measured and calculated transmission losses of sound waves through a helium layer

    NASA Technical Reports Server (NTRS)

    Norum, T. D.

    1973-01-01

    An experiment was performed to measure the transmission losses of sound waves traversing an impedance layer. The sound emanated from a point source and the impedance layer was created by a low-speed helium jet. The transmission losses measured were of the order of 12 db for frequencies of the source between 4 and 12 kHz. These losses are greater than those predicted from analysis when the observer angle is less than about 35 deg, but less than those predicted for larger observer angles. The experimental results indicate that appreciable noise reductions can be realized for an observer shielded by an impedance layer, irrespective of his position relative to the source of sound.

  7. Adjusting Measured Weight Loss of Aged Graphite Fabric/PMR-15 Composites

    NASA Technical Reports Server (NTRS)

    Bowles, Kenneth J.

    1998-01-01

    The purposes of this study were to evaluate the growth of the surface damage layer in polymer matrix composites (PMC's) fabricated with graphite fabric reinforcement and to determine the effects of the cut-surface degradation on the overall thermo-oxidative (TOS) stability of these materials. Four important conclusions were made about the TOS behavior of T650-35/PNIR- 15 fabric-reinforced composites: (1) Three stages of composite weight loss were seen on the plot of weight loss versus aging time; (2) the depth of the cut-edge damage is related to the composite thickness; (3) the actual weight loss realized by a mechanical test specimen that has had all the aging-induced cut-edge damage removed during the preparation process is significantly less than the weight loss measured using specimens with a high percentage of cut edges exposed to the damaging environment; and (4) an extrapolation of a section of the weight loss curve can be used to obtain a more correct estimate of the actual weight loss after extended periods of aging at elevated temperatures.

  8. Measuring Migratory Grief and Loss Associated with the Experience of Immigration

    ERIC Educational Resources Information Center

    Casado, Banghwa Lee; Hong, Michin; Harrington, Donna

    2010-01-01

    Objectives: The Migratory Grief and Loss Questionnaire (MGLQ) was designed to measure the grief experience associated with immigration. This article reports the development and psychometric properties of a Chinese-version of MGLQ. Methods: An exploratory factor analysis (EFA) using maximum likelihood extraction with varimax rotation was conducted…

  9. 12 CFR Appendix D to Subpart A of... - Description of the Loss Severity Measure

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 5 2012-01-01 2012-01-01 false Description of the Loss Severity Measure D Appendix D to Subpart A of Part 327 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION REGULATIONS AND STATEMENTS OF GENERAL POLICY ASSESSMENTS In General Pt. 327, Subpt. A, App. D Appendix D to Subpart A of...

  10. 12 CFR Appendix D to Subpart A of... - Description of the Loss Severity Measure

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Description of the Loss Severity Measure D Appendix D to Subpart A of Part 327 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION REGULATIONS AND STATEMENTS OF GENERAL POLICY ASSESSMENTS In General Pt. 327, Subpt. A, App. D Appendix D to Subpart A of...

  11. ESTIMATION OF DIFFUSION LOSSES WHEN SAMPLING DIESEL AEROSOL: A QUALITY ASSURANCE MEASURE

    EPA Science Inventory

    A fundamental component of the QA work for the assessment of instruments and sampling system performance was the investigation of particle losses in sampling lines. Along the aerosol sample pathway from its source to the collection media or measuring instrument, some nano-size p...

  12. 12 CFR Appendix D to Subpart A of... - Description of the Loss Severity Measure

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Description of the Loss Severity Measure D Appendix D to Subpart A of Part 327 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION REGULATIONS AND STATEMENTS OF GENERAL POLICY ASSESSMENTS In General Pt. 327, Subpt. A, App. D Appendix D to Subpart A of...

  13. Diagnostic measure to quantify loss of clinical components in multi-lead electrocardiogram.

    PubMed

    Tripathy, R K; Sharma, L N; Dandapat, S

    2016-03-01

    In this Letter, a novel principal component (PC)-based diagnostic measure (PCDM) is proposed to quantify loss of clinical components in the multi-lead electrocardiogram (MECG) signals. The analysis of MECG shows that, the clinical components are captured in few PCs. The proposed diagnostic measure is defined as the sum of weighted percentage root mean square difference (PRD) between the PCs of original and processed MECG signals. The values of the weight depend on the clinical importance of PCs. The PCDM is tested over MECG enhancement and a novel MECG data reduction scheme. The proposed measure is compared with weighted diagnostic distortion, wavelet energy diagnostic distortion and PRD. The qualitative evaluation is performed using Spearman rank-order correlation coefficient (SROCC) and Pearson linear correlation coefficient. The simulation result demonstrates that the PCDM performs better to quantify loss of clinical components in MECG and shows a SROCC value of 0.9686 with subjective measure. PMID:27222735

  14. Convective loss measurements at the 10 MW/sub e/ Solar Thermal Central Receiver Pilot Plant

    SciTech Connect

    Stoddard, M C

    1986-01-01

    Experiments were performed at the 10 MW/sub e/ Solar Thermal Central Receiver Pilot Plant to measure the convective heat transfer from the receiver. Determining the convective loss will help reduce the uncertainty in the calculation of thermal efficiency for solar central receivers. Two types of results are presented from the data: (1) the overall receiver convective coefficient, and (2) detailed information on the local (panel) losses as a function of wind direction. The overall measured convective coefficient is also compared with predictions from correlations developed to calculate the convective coefficient. The comparison between the measured and predicted convective coefficients is good, although the correlations tend to overpredict the measured data by about 10%.

  15. Measurements of the transverse resistance and eddy current losses in a cable-in-conduit conductor

    NASA Astrophysics Data System (ADS)

    Keilin, V. E.; Kovalev, I. A.; Kruglov, S. L.; Lelekhov, S. A.; Il'in, A. A.; Naumov, A. V.; Shcherbakov, V. I.; Shutov, K. A.

    2015-11-01

    In the case of plasma current interruption in tokamaks, the conductor of toroidial field (TF) coils experiences the action of a pulsed decreasing magnetic field (PDMF) parallel to the conductor's axis. To estimate the stability of a cable-in-conduit conductor against the PDMF, a new experimental method to study different types of losses is applied. This method exploits a high sensitivity of temperature and gas pressure to input energy in a closed volume. It allows one to measure hysteresis losses with a rather high accuracy (provided that the rate of change of the PDMF is low) and a sum of hysteresis losses and eddy current losses (when the rate of change of the PDMF is high). An experimental setup to measure the transverse (circumferential) resistance and losses has been developed at the National Research Centre Kurchatov Institute. A Russianmade Nb3Sn conductor intended for the TF coils of the International Thermonuclear Experimental Reactor is subjected to a PDMF with different amplitudes and characteristic times. The electromagnetic time constant and the transverse resistivity of the conductor are experimentally determined. The maximum temperature of strands under the action of the PDMF is calculated.

  16. Individual loss distribution measurement in 32-branched PON using pulsed pump-probe Brillouin analysis.

    PubMed

    Takahashi, Hiroshi; Ito, Fumihiko; Kito, Chihiro; Toge, Kunihiro

    2013-03-25

    We describe loss distribution measurement in a passive optical network (PON) using pulsed pump-probe Brillouin analysis. A preliminary experiment is demonstrated using a 32-branched PON constructed in the laboratory. We analyze the signal to noise ratio of this measurement and show that the method can realize a 25 dB dynamic range in 90 seconds (10000 times averaging), with an event location resolution of 10 m, and a fiber length identification resolution of 2 m. PMID:23546056

  17. Precision bone and muscle loss measurements by advanced, multiple projection DEXA (AMPDXA) techniques for spaceflight applications

    NASA Technical Reports Server (NTRS)

    Charles, H. K. Jr; Beck, T. J.; Feldmesser, H. S.; Magee, T. C.; Spisz, T. S.; Pisacane, V. L.

    2001-01-01

    An advanced, multiple projection, dual energy x-ray absorptiometry (AMPDXA) scanner system is under development. The AMPDXA is designed to make precision bone and muscle loss measurements necessary to determine the deleterious effects of microgravity on astronauts as well as develop countermeasures to stem their bone and muscle loss. To date, a full size test system has been developed to verify principles and the results of computer simulations. Results indicate that accurate predictions of bone mechanical properties can be determined from as few as three projections, while more projections are needed for a complete, three-dimensional reconstruction. c 2001. Elsevier Science Ltd. All rights reserved.

  18. Microwave continuum measurements and estimates of mass loss rates for cool giants and supergiants

    NASA Technical Reports Server (NTRS)

    Drake, S. A.; Linsky, J. L.

    1986-01-01

    Attention is given to the results of a sensitive, 6-cm radio continuum survey conducted with the NRAO VLA of 39 of the nearest single cool giants and supergiants of G0-M5 spectral types; the survey was conducted in order to obtain accurate measurements of the mass loss rates of ionized gas for a representative sample of such stars, in order to furnish constraints for, and a better understanding of, the total mass loss rates. The inferred angular diameters for the cool giant sources are noted to be twice as large as photospheric angular diameters, implying that these stars are surrounded by extended chromospheres containing warm partially ionized gas.

  19. First measurements of bulk and shear mechanical loss in optical thin film materials

    NASA Astrophysics Data System (ADS)

    Abernathy, Matthew; Harry, Gregory; Newport, Jonathan; Fair, Hanna; Hickey, Sam; Grettarsson, Andri; Penn, Steve; LIGO Collaboration

    As advanced gravitational wave detectors come online, and the possibility of the first gravitational wave detection nears, plans for the next generation of gravitational wave detectors are already in the works. These new detectors, and those already planned for the future, are expected to be limited in their most sensitive frequency bands by the Brownian thermal noise generated within the optical thin films used to produce the interferometer mirrors. In order to fully predict the level of this Brownian noise, it is necessary to know the two independent mechanical moduli (Young modulus and Poisson ratio, Bulk and Shear moduli, etc.) as well as their associated mechanical loss parameters. Traditional measurements of the mechanical loss of thin films has measured only one linear combination of these two loss parameters. Here, we present measurements of the bulk and shear mechanical loss of tantalum pentoxide (tantala) thin films made by taking advantage of the differing ratios of elastic deformation in the various resonant modes of a coated silica disc. These results may have immediate implications for the ultimate sensitivity of currently operated gravitational wave detectors.

  20. Dew-point hygrometry system for measurement of evaporative water loss in infants.

    PubMed

    Ariagno, R L; Glotzbach, S F; Baldwin, R B; Rector, D M; Bowley, S M; Moffat, R J

    1997-03-01

    Evaporation of water from the skin is an important mechanism in thermal homeostasis. Resistance hygrometry, in which the water vapor pressure gradient above the skin surface is calculated, has been the measurement method of choice in the majority of pediatric investigations. However, resistance hygrometry is influenced by changes in ambient conditions such as relative humidity, surface temperature, and convection currents. We have developed a ventilated capsule method that minimized these potential sources of measurement error and that allowed second-by-second, long-term, continuous measurements of evaporative water loss in sleeping infants. Air with a controlled reference humidity (dew-point temperature = 0 degree C) is delivered to a small, lightweight skin capsule and mixed with the vapor on the surface of the skin. The dew point of the resulting mixture is measured by using a chilled mirror dew-point hygrometer. The system indicates leaks, is mobile, and is accurate within 2%, as determined by gravimetric calibration. Examples from a recording of a 13-wk-old full-term infant obtained by using the system give evaporative water loss rates of approximately 0.02 mgH2O.cm-2.min-1 for normothermic baseline conditions and values up to 0.4 mgH2O.cm-2. min-1 when the subject was being warmed. The system is effective for clinical investigations that require dynamic measurements of water loss. PMID:9074995

  1. Loss-compensation technique for fiber-optic sensors and its application to displacement measurements

    NASA Technical Reports Server (NTRS)

    Beheim, Glenn

    1987-01-01

    This report describes a new type of intensity-modulating fiber-optic sensor which has high immunity to the effects of variations in the losses of the fiber-link. A variable-splitting-ratio transducer is used to differentially modulate the intensities of the light which it transmits and reflects. Using a four-fiber optical link, light is impinged onto the transducer from either direction, and in each case, the transmitted and reflected signals are measured. These four signals are then processed to remove the effects of the fiber and connector losses. Loss-compensated sensors of angular position and displacement are described, and their outputs are shown to be highly stable despite considerable variations in the transmissivities of the fiber-link components.

  2. Dynamic measurement of heat loss coefficients through Trombe wall glazing systems

    SciTech Connect

    Balcomb, J.D.

    1981-01-01

    A Trombe wall presents a unique opportunity to measure the heat-loss coefficient through the glazing system because the wall itself can be used as a heat meter. Since the instantaneous heat flux through the outer wall surface can be determined, the heat loss coefficient at night can be calculated by dividing by the wall surface-to-ambient temperature difference. This technique has been used to determine heat-loss coefficients for Los Alamos test rooms during the winter of 1980-1981. Glazing systems studied include single and double glazing both with and without night insulation used in conjunction with a flat black paint, and both single and double glazing used in conjunction with a selective surface.

  3. Coincidence measurements of electron capture and loss in ion-atom collisions

    SciTech Connect

    DuBois, R.D.

    1990-09-01

    Collisions between fast, fully stripped projectiles and atomic targets predominantly result in target electrons being ejected to the continuum. For fast partially stripped projectiles which bring weakly bound electrons into the collision, projectile ionization can also contribute to the observed electron spectra. At lower impact velocities, electron capture by the projectile ion becomes important and higher order processes, often referred to as transfer ionization, can be a significant source of free electrons. In recent years, coincidence techniques have been used to evaluate the relative importance of electron capture and loss in free electron production, to separate the capture and loss contributions from those resulting from target ionization alone, and to provide more detailed information about electron capture and loss mechanisms than is available from total cross section measurements. A brief survey of these experiments will be presented. 23 refs., 9 figs.

  4. Measurements on magnetized GdBCO pellets subjected to small transverse ac magnetic fields at very low frequency: Evidence for a slowdown of the magnetization decay

    NASA Astrophysics Data System (ADS)

    Fagnard, Jean-Francois; Kirsch, Sébastien; Morita, Mitsuru; Teshima, Hidekazu; Vanderheyden, Benoit; Vanderbemden, Philippe

    2015-05-01

    Due to their ability to trap large magnetic inductions, superconducting bulk materials can be used as powerful permanent magnets. The permanent magnetization of such materials, however, can be significantly affected by the application of several cycles of a transverse variable magnetic field. In this work, we study, at T = 77 K, the long term influence of transverse ac magnetic fields of small amplitudes (i.e. much smaller than the full penetration field) on the axial magnetization of a bulk single grain superconducting GdBCO pellet over a wide range of low frequencies (1 mHz-20 Hz). Thermocouples are placed against the pellet surface to probe possible self-heating of the material during the experiments. A high sensitivity cryogenic Hall probe is placed close to the surface to record the local magnetic induction normal to the surface. The results show first that, for a given number of applied triangular transverse cycles, higher values of dBapp/dt induce smaller magnetization decays. An important feature of practical interest is that, after a very large number of cycles which cause the loss of a substantial amount of magnetization (depending on the amplitude and the frequency of the field), the rate of the magnetization decay goes back to its initial value, corresponding to the relaxation of the superconducting currents due to flux creep only. In the amplitude and frequency range investigated, the thermocouples measurements and a 2D magneto-thermal modelling show no evidence of sufficient self-heating to affect the magnetization so that the effect of the transverse magnetic field cycles on the trapped magnetic moment is only attributed to a redistribution of superconducting currents in the volume of the sample and not to a thermal effect.

  5. The first mass and angular momentum loss measurements for a CV-like binary

    NASA Astrophysics Data System (ADS)

    Drake, Jeremy

    2014-10-01

    The period distribution of close binaries, cataclysmic variables, novae and single-degenerate SN1a progenitor candidates is largely controlled by magnetically-driven mass and angular momentum loss (AML) from the M dwarf secondary. The mass loss rates for these spun-up stars remain essentially unknown and impossible to observe directly, with likely values in the range 1e-12 to 1e-15 Msun/yr. AML presciptions for CVs differ by orders of magnitude. One way to measure the mass loss rate is to observe the dM wind accrete onto its WD companion in a pre-CV very close to Roche Lobe overflow but lacking the obscuring complications and emission from an accretion disk. The measurement can be combined with realistic MHD models to understand the accretion fraction, the mass that escapes, and the AML. The best-studied nearby pre-CV is QS Vir (48pc, P=3.6hr). However, its wind accretion rates measured from 1999 HST UV spectra of the WD metal absorption lines and 2006 XMM-Newton CCD spectroscopy differ by a factor of a thousand, pointing to either a dominant CME stochastic component, or a "magnetic switch" found in MHD simulations and driven by cyclic activity on the M dwarf. HST COS spectra combined with XMM-Newton monitoring on timescales from weeks to years will tease out CME vs cyclic accretion variations. UV and X-ray measurements will provide the first consistency check of both accretion rate measurement methods. MHD models tailored to the system will enable the first quasi-direct measurements of the mass loss and AML from a CV-like binary. Our project requires 6 HST/COS orbits in Cycles 22-24, and 60ksec on XMM in Cycle 22

  6. Measurements of the complex permittivity of loss ceramics at microwave frequencies and over large temperature ranges

    SciTech Connect

    Meng, B.; Booske, J.; Cooper, R.; Klein, B.

    1995-12-31

    A system has been developed for measuring the complex permittivities of low loss ceramic materials at frequencies from 2 GHz to 20 GHz and over a temperature range 20-1000{degrees}C. The measurement technique involves a, modified version of tile conventional cavity perturbation method. This extended cavity perturbation technique is presented. Details of the design and fabrication of the circular cylindrical cavity and the input and output coupling transmission lines are discussed. Data are presented for an illustrative measurement of the complex microwave dielectric properties of NaCl single crystals between 20-400{degrees}C. The experimental results are in excellent agreement with theoretical models.

  7. Monochromated, spatially resolved electron energy-loss spectroscopic measurements of gold nanoparticles in the plasmon range.

    PubMed

    Schaffer, B; Riegler, K; Kothleitner, G; Grogger, W; Hofer, F

    2009-02-01

    Gold nanoparticles show optical properties different from bulk material due to resonance phenomena which depend on local structure and geometry. Electron energy-loss spectrometry (EELS) in scanning transmission electron microscopy (STEM) allows the spatially resolved measurement of these properties at a resolution of few nanometers. In this work, the first monochromated measurements of gold nanoparticles (spheres, rods and triangles) are presented. Due to the improved energy resolution of about 0.2 eV, surface plasmon excitations at energies below 1 eV could be accurately measured from raw experimental data. PMID:18722779

  8. Ozone profiles and chemical loss rates in the tropical stratosphere deduced from backscatter ultraviolet measurements

    NASA Technical Reports Server (NTRS)

    Frederick, J. E.; Hays, P. B.; Guenther, B. W.; Heath, D. F.

    1978-01-01

    Analysis of data obtained by the backscatter ultraviolet (BUV) experiment on the Atmosphere Explorer E satellite has provided equatorial ozone mixing ratio profiles for equinox and solstice conditions. The combination of these results with a pure oxygen chemical model yields the rate of odd oxygen loss due to the sum of the odd hydrogen, nitrogen, and chlorine cycles. Use of recent mid-latitude stratospheric measurements of HO(x), NO(x), and ClO(x) with the BUV data provides an independent calculation of the catalytic loss. Below 45 km the agreement between the two sets of loss rates is satisfactory. At higher altitudes the odd hydrogen cycle provides far more O(x) loss than can be tolerated by the BUV measurements if the photodissociation of O2 is the only source and has the currently accepted magnitude. The results suggest either a tropical HO(x) concentration smaller than is now believed or the presence of a very large source of odd oxygen in the upper stratosphere and lower mesosphere.

  9. Measurement of spinal or peripheral bone mass to estimate early postmenopausal bone loss

    SciTech Connect

    Riis, B.J.; Christiansen, C.

    1988-04-01

    This report presents data from 153 healthy, early postmenopausal women who were randomly allocated to two years of treatment with estrogen or placebo. Bone mineral content in the forearms was measured by single-photon absorptiometry, and bone mineral density of the lumbar spine and total-body bone mineral by dual-photon absorptiometry, before and after one and two years of treatment. At the end of the two years, there were highly significant differences of 6 to 7 percent between the estrogen and the placebo groups at all sites measured. The range of the changes of the spine measurement was twice that of the forearm and total-body measurements. It is concluded that measurement of the forearm by single-photon absorptiometry is superior to measurement of the spine by dual-photon absorptiometry both in clinical studies and in the individual patient for detecting estrogen-dependent bone loss and its treatment by estrogen replacement.

  10. SNR Loss: A new objective measure for predicting speech intelligibility of noise-suppressed speech

    PubMed Central

    Ma, Jianfen; Loizou, Philipos C.

    2010-01-01

    Most of the existing intelligibility measures do not account for the distortions present in processed speech, such as those introduced by speech-enhancement algorithms. In the present study, we propose three new objective measures that can be used for prediction of intelligibility of processed (e.g., via an enhancement algorithm) speech in noisy conditions. All three measures use a critical-band spectral representation of the clean and noise-suppressed signals and are based on the measurement of the SNR loss incurred in each critical band after the corrupted signal goes through a speech enhancement algorithm. The proposed measures are flexible in that they can provide different weights to the two types of spectral distortions introduced by enhancement algorithms, namely spectral attenuation and spectral amplification distortions. The proposed measures were evaluated with intelligibility scores obtained by normal-hearing listeners in 72 noisy conditions involving noise-suppressed speech (consonants and sentences) corrupted by four different maskers (car, babble, train and street interferences). Highest correlation (r=−0.85) with sentence recognition scores was obtained using a variant of the SNR loss measure that only included vowel/consonant transitions and weak consonant information. High correlation was maintained for all noise types, with a maximum correlation (r=−0.88) achieved in street noise conditions. PMID:21503274

  11. Measurement of loss in superconducting microstrip at millimeter-wave frequencies

    NASA Astrophysics Data System (ADS)

    Gao, Jiansong; Vayonakis, Anastasios; Noroozian, Omid; Zmuidzinas, Jonas; Day, Peter K.; Leduc, Henry G.

    2009-12-01

    We have developed a new technique for accurate measurement of the loss of superconducting microstrips at mm-wave frequencies. In this technique, we optically couple power to slot antenna, which is connected to one port of a hybrid coupler. One of the output ports of the hybrid delivers power to a series of mm-wave microstrip resonators which are capacitively coupled to a feedline followed by an MKID (microwave kinetic inductance detector) that measures the transmitted power. Two other MKIDs are connected to the remaining ports of the hybrid to measure the total incident optical power and the power reflected from the mm-wave resonators, allowing |S21|2 and |S11|2 to be accurately determined and resonance frequency fr and quality factor Q to be retrieved. We have fabricated such a Nb/SiO2/Nb microstrip loss test device which contains several mm- wave resonators with fr˜100 GHz and measured it at 30 mK. All the resonators have shown internal quality factor Qi˜500-2000, suggesting a loss tangent of ˜5×10-4-2×10-3 for the SiO2 in use. For comparison, we have also fabricated a 5 GHz microstrip resonator on the same chip and measured it with a network analyzer. The loss tangent at 5 GHz derived from fitting the f0 and Q data to the two-level system (TLS) model is 6×10-4, about the same as from the mm-wave measurement. This suggests that the loss at both microwave and mm-wave frequencies is probably dominated by the TLS in SiO2. Our results are of direct interest to mm/submm direct detection applications which use microstrip transmission lines (such as antenna-coupled MKIDs and transition-edge sensors), and other applications (such as on-chip filters). Our measurement technique is applicable up to approximately 1 THz and can be used to investigate a range of dielectrics.

  12. Damping loss factor estimation of two-dimensional orthotropic structures from a displacement field measurement

    NASA Astrophysics Data System (ADS)

    Cherif, Raef; Chazot, Jean-Daniel; Atalla, Noureddine

    2015-11-01

    This paper presents a damping loss factor estimation method of two-dimensional orthotropic structures. The method is based on a scanning laser vibrometer measurement. The dispersion curves of the studied structures are first estimated at several chosen angles of propagation with a spatial Fourier transform. Next the global damping loss factor is evaluated with the proposed inverse wave method. The method is first tested using numerical results obtained from a finite element model. The accuracy of the proposed method is then experimentally investigated on an isotropic aluminium panel and two orthoropic sandwich composite panels with a honeycomb core. The results are finally compared and validated over a large frequency band with classical methods such as the half-power bandwidth method (3 dB method), the decay rate method and the steady-state power input method. The present method offers the possibility of structural characterization with a simple measurement scan.

  13. Measured and modeled HOCl profiles in the mid-latitude stratosphere : implication for ozone loss

    NASA Technical Reports Server (NTRS)

    Kovalenko, L. J.; Salawitch, R. J.; Blavier, J. -F.; Sen, B.; Toon, G. C.; Jucks, K. W.; Johnson, D. G.; Stachnik, R. A.; Margitan, J. J.

    2004-01-01

    The HOCl catalytic cycle is an efficient ozone loss mechanism in the lower mid-latitude stratosphere. We use a diurnal steady-state photochemical model to calculate profiles of HOCl for conditions encountered by a number of high-altitude balloon flights. To assess how well this model represents ozone loss by the HOCl cycle, we compare our calculations of HOCl and its precursors Cl0 and HO2 with measurements obtained by an FTIR solar absorption spectrometer (MkIV), a far-infrared emission spectrometer (FIRS-2), and a submillimetenvave limb sounder (SLS). We then evaluate these comparisons in light of a number of recent laboratory studies of the main formation mechanism of HOCl, the reaction of Cl0 + HO2. Those studies measured both the reaction rate constant and the quantum yield for a second product pathway, formation of HCl.

  14. Effects of Remediation Measures On Soil Available Phosphorus and Induced Phoshorus Losses

    NASA Astrophysics Data System (ADS)

    Schaerer, M.; Vollmer, T.; Sinaj, S.; Stamm, C.; Fluehler, H.; Frossard, E.

    Permanent grassland soils in areas with high livestock density are especially critical, since large phosphorus (P)-surpluses have accumulated in the topsoil due to high fertilizer and manure application rates. In Switzerland, programs are planned to reduce diffuse P-losses from agricultural land to surface waters. However, the efficiency and practicability of the proposed measures are mainly hypothetical. Therefore, we have established two field trials on grassland soils with the goal to study at the plot scale the effect of three "remediation measures" on soil P availability and induced P-losses. The total P contents in the 0- to 2-cm depth of both sites were high, 1.4 and 1.9 g P kg-1 soil respectively at site I and site II and decreased strongly in the lower parts of the both soil profiles. The concentrations of isotopically exchangeable P within 1 minute (E1min, readily available P) for the same depth were also very high, 58 and 27 mg P kg soil for the site I and II, respectively. These values decrease rapidly with depth. The experimental measures under study include (i) a control with normal P- input, (ii) zero P-input, (iii) a single tillage operation with zero P-input and (iv) zero P-input + a single tillage operation + addition of Fe-oxide (Fe-(II)-sulfate solution applied on the top of a soil/ calciumhydroxide mixture). The monitoring of P-losses includes sprinkling experiments inducing surface runoff, as well as runoff measurements under natural rainfall conditions. The remediation measures were applied in three or four replicates at both sites in early summer 2001. In the year 2000, the "status quo" of P-losses from the studied plots was also evaluated. Results from the first monitoring year (2000) indicated that both sites were potential source areas for the eutrophication of surface waters with respect to P-mobilization by runoff water. Sprinkling with deionized water caused runoff containing 0.8 and 0.9 mg total P L-1 at the site I and II

  15. Measurements of Prompt and MHD-Induced Fast Ion Loss from National Spherical Torus Experiment Plasmas

    SciTech Connect

    D.S. Darrow; S.S. Medley; A.L. Roquemore; W.W. Heidbrink; A. Alekseyev; F.E. Cecil; J. Egedal; V.Ya. Goloborod'ko; N.N. Gorelenkov; M. Isobe; S. Kaye; M. Miah; F. Paoletti; M.H. Redi; S.N. Reznik; A. Rosenberg; R. White; D. Wyatt; V.A. Yavorskij

    2002-10-15

    A range of effects may make fast ion confinement in spherical tokamaks worse than in conventional aspect ratio tokamaks. Data from neutron detectors, a neutral particle analyzer, and a fast ion loss diagnostic on the National Spherical Torus Experiment (NSTX) indicate that neutral beam ion confinement is consistent with classical expectations in quiescent plasmas, within the {approx}25% errors of measurement. However, fast ion confinement in NSTX is frequently affected by magnetohydrodynamic (MHD) activity, and the effect of MHD can be quite strong.

  16. Reservoir water loss modeling and measurements at Fenton Hill, New Mexico

    SciTech Connect

    Brown, D.W.

    1989-01-01

    An extensive series of pressurized reservoir water loss experiments are presently being conducted in the deeper Phase II reservoir, at the Laboratory's Fenton Hill site in north-central New Mexico. The objectives of these experiments are: to measure the reservoir water leak-off rate at a number of equilibrium reservoir pressure levels, and as a function of time; and with this pressure- and time-dependent water-loss data, to determine the joint dilation (i.e., mean joint porosity) of the reservoir as a function of pressure up to about 24 MPa (as measured at the surface). The permeability model of Gangi has been used to explain the Phase II reservoir water loss as measured during two reservoir flow tests of 7 and 30 days duration. During the 30-day flow test, the model strongly suggests that the reservoir was actively growing by fracture extension, even at injection pressures as low as 27 MPa, which is confirmed by our seismic observations. 3 refs., 6 figs., 1 tab.

  17. LOSS OF OTOLITH FUNCTION WITH AGE IS ASSOCIATED WITH INCREASED POSTURAL SWAY MEASURES

    PubMed Central

    Serrador, Jorge M.; Lipsitz, Lewis A.; Gopalakrishnan, Gosala S.; Black, F. Owen; Wood, Scott J.

    2009-01-01

    Background Loss of balance and increased fall risk is a common problem associated with aging. Changes in vestibular function occur with aging but the contribution of reduced vestibular otolith function to fall risk remains unknown. Methods We examined a population of 151 healthy individuals (aged 21–93) for both balance (sway measures) and otolith counter-rolling (OCR) function. We assessed balance function with eyes open and closed on a firm surface, eyes open and closed on a foam surface and OCR during ±20 degree roll tilt at 0.005 Hz. Results Subjects demonstrated a significant age-related reduction in OCR and increased postural sway. The effect of age on OCR was greater in females than males. The reduction in OCR was strongly correlated with the mediolateral measures of sway with eyes closed. This correlation was also present in the elderly group alone, suggesting that aging alone does not account for this effect. Conclusions OCR decreases linearly with age and at a greater rate in females than males. This loss of vestibular otolith-ocular function is associated with increased mediolateral measures of sway which have been shown to be related to increased risk of falls. These data suggest a role for loss of otolith function in contributing to fall risk in the elderly. Further prospective, longitudinal studies are necessary to confirm these findings. PMID:19716400

  18. MEASUREMENT OF RF LOSSES DUE TO TRAPPED FLUX IN A LARGE-GRAIN NIOBIUM CAVITY

    SciTech Connect

    Gianluigi Ciovati; Alex Gurevich

    2008-01-23

    Trapped magnetic field in superconducting niobium is a well known cause of radio-frequency (RF) residual losses. In this contribution, we present the results of RF tests on a single-cell cavity made of high-purity large grain niobium before and after allowing a fraction of the Earth magnetic field to be trapped in the cavity during the cooldown below the critical temperature Tc. This experiment has been done on the cavity before and after a low temperature baking. Temperature mapping allowed us to determine the location of hot-spots with high losses and to measure their field dependence. The results show not only an increase of the low-field residual resistance, but also a larger increase of the surface resistance for intermediate RF field (higher “medium field Q-slope”), which depends on the amount of the trapped flux. These additional field-dependent losses can be described as losses of pinned vortices oscillating under the applied RF magnetic field.

  19. MEASUREMENT OF RF LOSSES DUE TO TRAPPED FLUX IN A LARGE-GRAIN NIOBIUM CAVITY

    SciTech Connect

    Gianluigi Ciovati; Alex Gurevich

    2008-01-23

    Trapped magnetic field in superconducting niobium is a well known cause of radio-frequency (RF) residual losses. In this contribution, we present the results of RF tests on a single-cell cavity made of high-purity large grain niobium before and after allowing a fraction of the Earth’s magnetic field to be trapped in the cavity during the cooldown below the critical temperature Tc. This experiment has been done on the cavity before and after a low temperature baking. Temperature mapping allowed us to determine the location of hot-spots with high losses and to measure their field dependence. The results show not only an increase of the low-field residual resistance, but also a larger increase of the surface resistance for intermediate RF field (higher "medium field Qslope"), which depends on the amount of the trapped flux. These additional field-dependent losses can be described as losses of pinned vortices oscillating under the applied RF magnetic field.

  20. Power loss measurement of implantable wireless power transfer components using a Peltier device balance calorimeter

    NASA Astrophysics Data System (ADS)

    Leung, Ho Yan; Budgett, David M.; Taberner, Andrew; Hu, Patrick

    2014-09-01

    Determining heat losses in power transfer components operating at high frequencies for implantable inductive power transfer systems is important for assessing whether the heat dissipated by the component is acceptable for implantation and medical use. However, this is a challenge at high frequencies and voltages due to limitations in electronic instrumentation. Calorimetric methods of power measurement are immune to the effects of high frequencies and voltages; hence, the measurement is independent of the electrical characteristics of the system. Calorimeters have been widely used to measure the losses of high power electrical components (>50 W), however it is more difficult to perform on low power components. This paper presents a novel power measurement method for components dissipating anywhere between 0.2 W and 1 W of power based on a heat balance calorimeter that uses a Peltier device as a balance sensor. The proposed balance calorimeter has a single test accuracy of ±0.042 W. The experimental results revealed that there was up to 35% difference between the power measurements obtained with electrical methods and the proposed calorimeter.

  1. Hydrodynamic corrections to contact resonance atomic force microscopy measurements of viscoelastic loss tangenta)

    NASA Astrophysics Data System (ADS)

    Tung, Ryan C.; Killgore, Jason P.; Hurley, Donna C.

    2013-07-01

    We present a method to improve accuracy in measurements of nanoscale viscoelastic material properties with contact resonance atomic force microscope methods. Through the use of the two-dimensional hydrodynamic function, we obtain a more precise estimate of the fluid damping experienced by the cantilever-sample system in contact resonance experiments, leading to more accurate values for the tip-sample damping and related material properties. Specifically, we consider the damping and added mass effects generated by both the proximity of the cantilever to the sample surface and the frequency dependence on the hydrodynamic loading of the system. The theoretical correction method is implemented on experimental contact resonance measurements. The measurements are taken on a thin polystyrene film and are used to determine the viscoelastic loss tangent, tan δ, of the material. The magnitude of the corrections become significant on materials with low tan δ (<0.1) and are especially important for measurements made with the first flexural mode of vibration.

  2. Determination of critical current density and transition temperature of YBa sub 2 Cu sub 3 O sub 7 minus x thin films by measurement of ac susceptibility

    SciTech Connect

    Li, Y.; Noh, D.; Gallois, B. ); Tompa, G.S.; Norris, P.E.; Zawadzki, P.A. )

    1990-10-01

    A technique for the determination of the critical current of superconducting thin films by a current-dependent ac susceptibility measurement has been developed. This method has been used to characterize superconducting YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} films grown {ital in situ} at 1073 K by metalorganic chemical vapor deposition. Two superconducting phases with transition temperatures of 91 and 84 K have been detected by the measurement of ac susceptibility as a function of temperature even though the variation of resistance with temperature indicated a sharp transition. The critical current densities of the two superconducting phases have been determined from the variations of ac susceptibility with current at constant temperature and found to be equal to 1.14{times}10{sup 4} A/cm{sup 2} and 3.6{times}10{sup 3} A/cm{sup 2} at 75 K. The advantages of the technique in comparison to current methods of measurement of critical current are discussed.

  3. Measured and simulated heavy-ion beam loss patterns at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Hermes, P. D.; Bruce, R.; Jowett, J. M.; Redaelli, S.; Salvachua Ferrando, B.; Valentino, G.; Wollmann, D.

    2016-05-01

    The Large Hadron Collider (LHC) at CERN pushes forward to new regimes in terms of beam energy and intensity. In view of the combination of very energetic and intense beams together with sensitive machine components, in particular the superconducting magnets, the LHC is equipped with a collimation system to provide protection and intercept uncontrolled beam losses. Beam losses could cause a superconducting magnet to quench, or in the worst case, damage the hardware. The collimation system, which is optimized to provide a good protection with proton beams, has shown a cleaning efficiency with heavy-ion beams which is worse by up to two orders of magnitude. The reason for this reduced cleaning efficiency is the fragmentation of heavy-ion beams into isotopes with a different mass to charge ratios because of the interaction with the collimator material. In order to ensure sufficient collimation performance in future ion runs, a detailed theoretical understanding of ion collimation is needed. The simulation of heavy-ion collimation must include processes in which 82+208Pb ions fragment into dozens of new isotopes. The ions and their fragments must be tracked inside the magnetic lattice of the LHC to determine their loss positions. This paper gives an overview of physical processes important for the description of heavy-ion loss patterns. Loss maps simulated by means of the two tools ICOSIM [1,2] and the newly developed STIER (SixTrack with Ion-Equivalent Rigidities) are compared with experimental data measured during LHC operation. The comparison shows that the tool STIER is in better agreement.

  4. What measured blood loss tells us about postpartum bleeding: a systematic review

    PubMed Central

    Sloan, NL; Durocher, J; Aldrich, T; Blum, J; Winikoff, B

    2010-01-01

    Background Meta-analyses of postpartum blood loss and the effect of uterotonics are biased by visually estimated blood loss. Objectives To conduct a systematic review of measured postpartum blood loss with and without prophylactic uterotonics for prevention of postpartum haemorrhage (PPH). Search strategy We searched Medline and PubMed terms (labour stage, third) AND (ergonovine, ergonovine tartrate, methylergonovine, oxytocin, oxytocics or misoprostol) AND (postpartum haemorrhage or haemorrhage) and Cochrane reviews without any language restriction. Selection criteria Refereed publications in the period 1988–2007 reporting mean postpartum blood loss, PPH (≥500 ml) or severe PPH (≥1000 ml) following vaginal births. Data collection and analysis Raw data were abstracted into Excel by one author and then reviewed by a co-author. Data were transferred to SPSS 17.0, and copied into RevMan 5.0 to perform random effects meta-analysis. Main results The distribution of average blood loss (29 studies) is similar with any prophylactic uterotonic, and is lower than without prophylaxis. Compared with no uterotonic, oxytocin and misoprostol have lower PPH (OR 0.43, 95% CI 0.23–0.81; OR 0.73, 95% CI 0.50–1.08, respectively) and severe PPH rates (OR 0.61, 95% CI 0.29–1.29; OR 0.74, 95% CI 0.52–1.04, respectively). Oxytocin has lower PPH (OR 0.65, 95% CI 0.60–0.70) and severe PPH (OR 0.71, 95% CI 0.56–0.91) rates than misoprostol, but not in developing countries. Conclusion Oxytocin is superior to misoprostol in hospitals. Misoprostol substantially lowers PPH and severe PPH. A sound assessment of the relative merits of the two drugs is needed in rural areas of developing countries, where most PPH deaths occur. PMID:20406227

  5. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Bruce, R.; Assmann, R. W.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

    2014-08-01

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

  6. Modeling and Measurement of 39Ar Recoil Loss From Biotite as a Function of Grain Dimensions

    NASA Astrophysics Data System (ADS)

    Paine, J. H.; Nomade, S.; Renne, P. R.

    2004-12-01

    The call for age measurements with less than 1 per mil error puts a demand upon geochronologists to be aware of and quantify a number of problems which were previously negligible. One such factor is 39Ar recoil loss during sample irradiation, a phenomenon which is widely assumed to affect only unusually small crystals having exceptionally high surface/volume ratios. This phenomenon has important implications for thermochronologic studies seeking to exploit a range of closure temperatures arising from variable diffusion radii. Our study focuses on biotite, in which spatial isotope distributions cannot be reliably recovered by stepwise heating and which therefore lack recoil-diagnostic age spectrum behavior. Previous work by Renne et al. [Application of a deuteron-deuteron (D-D) neutron generator to 40Ar/39Ar geochronology, Applied Radiation and Isotopes, in press] used the SRIM code to calculate a ˜20% 39Ar recoil loss from the outermost 0.25 μ m of an infinite slab of phyllosillicate. This result is applied to measured grains of the biotite standard GA1550, a hypabyssal granite from the Mount Dromedary Complex, Australia. We measure the thickness and surface area of 166 grains and approximate the shape of each grain as a cylinder. Grain thickness ranges from 3 to 210 μ m, with an average grain radius of 350 μ m. We predict the amount of 39Ar recoil loss from each grain, finding an expected age error >0.1 % for grains thinner than 150 μ m, a >1% error for grain less than 10 μ m thick, and up to a 3% error for grains less than 3 μ m thick. These modeling results will be tested by analysis of the measured grains after irradiation in the Oregon State University TRIGA reactor. It is important to either account for 39Ar loss in thin biotite grains, or use sufficiently thick ones so that recoil loss is negligible. Our results indicate that only biotite grains thicker than 150 μ m should be used for neutron fluence monitoring in order to avoid bias greater than the

  7. A Functional Model for the Integration of Gains and Losses under Risk: Implications for the Measurement of Subjective Value

    ERIC Educational Resources Information Center

    Viegas, Ricardo G.; Oliveira, Armando M.; Garriga-Trillo, Ana; Grieco, Alba

    2012-01-01

    In order to be treated quantitatively, subjective gains and losses (utilities/disutilities) must be psychologically measured. If legitimate comparisons are sought between them, measurement must be at least interval level, with a common unit. If comparisons of absolute magnitudes across gains and losses are further sought, as in standard…

  8. Magnetic core loss of ultrahigh strength FeCo alloys

    NASA Astrophysics Data System (ADS)

    Cheng, X. M.; Zhang, X. K.; Zhang, D. Z.; Lee, S. H.; Duckham, A.; Weihs, T. P.; Cammarata, R. C.; Xiao, John Q.; Chien, C. L.

    2003-05-01

    Hiperco® 50 alloy heat treated between 450 and 650 °C exhibits superior mechanical properties. We report the measurements of the ac core loss at various frequencies up to 4500 Hz of the Hiperco® 50 alloy samples annealed at 450 and 650 °C. The 650 °C annealed specimens have lower ac core loss than that of the 450 °C annealed ones. The total core loss, consisting of contributions from hysteresis core loss and eddy-current core loss, depends on frequency f as af+bf2. The eddy-current loss of a single laminate is minor compared to the hysteresis loss.

  9. Loss-tolerant measurement-device-independent quantum random number generation

    NASA Astrophysics Data System (ADS)

    Cao, Zhu; Zhou, Hongyi; Ma, Xiongfeng

    2015-12-01

    Quantum random number generators (QRNGs) output genuine random numbers based upon the uncertainty principle. A QRNG contains two parts in general—a randomness source and a readout detector. How to remove detector imperfections has been one of the most important questions in practical randomness generation. We propose a simple solution, measurement-device-independent QRNG, which not only removes all detector side channels but is robust against losses. In contrast to previous fully device-independent QRNGs, our scheme does not require high detector efficiency or nonlocality tests. Simulations show that our protocol can be implemented efficiently with a practical coherent state laser and other standard optical components. The security analysis of our QRNG consists mainly of two parts: measurement tomography and randomness quantification, where several new techniques are developed to characterize the randomness associated with a positive-operator valued measure.

  10. Biochemical and cardiovascular measures in subjects with noise-induced hearing loss

    SciTech Connect

    Gold, S.; Haran, I.; Attias, J.; Shapira, I.; Shahar, A. )

    1989-11-01

    Reports on a potential relationship between noise-induced hearing loss (NIHL) and cardiovascular as well as biochemical measures are controversial. This study compares the means of certain cardiovascular and biochemical measures in subjects with NIHL with those in subjects exposed to similar occupational noise, but demonstrating normal hearing. This might indicate certain predisposing factors for NIHL. Eight hundred noise-exposed subjects were divided into two age-matched hearing groups (NIHL and normal hearing). The results showed that the mean values of all the variables examined in both hearing groups were within the normal range. No significant differences were found between the two groups in terms of the distribution of subjects for the indices measured.

  11. 10 orders of magnitude current measurement digitisers for the CERN beam loss systems

    NASA Astrophysics Data System (ADS)

    Viganò, W.; Alsdorf, M.; Dehning, B.; Kwiatkowski, M.; Venturini, G. G.; Zamantzas, C.

    2014-02-01

    A wide range current digitizer card is needed for the acquisition module of the beam loss monitoring systems in the CERN Injector Complex. The fully differential frequency converter allows measuring positive and negative input currents with a resolution of 31 nA in an integration window of 2 μs. Increasing the integration window, the dynamic range covers 21010 were the upper part of the range is converted by measuring directly the voltage drop on a resistor. The key elements of this design are the fully differential integrator and the switches operated by an FPGA. The circuit is designed to avoid any dead time in the acquisition and reliability and failsafe operational considerations are main design goals. The circuit will be discussed in detail and lab and field measurements will be shown.

  12. Measurement of α particle energy loss in biological tissue below 2 MeV

    NASA Astrophysics Data System (ADS)

    Stella, S.; Bortolussi, S.; Bruschi, P.; Portella, C.; Altieri, S.

    2009-09-01

    The energy loss of α particles crossing biological tissue at energies between 0.8 and 2.2 MeV has been measured. This energy range is very important for boron neutron capture therapy, based on the 10B( n, α) 7Li reaction, which emits α particles with energies of 1.78 and 1.47 MeV. One of the methods used for the measurement of the boron concentration in tissue is based on the deconvolution of the α spectra obtained from neutron irradiation of thin (70 μm) tissue samples. For this technique, a knowledge of the behaviour of the energy loss of the particles in the irradiated tissue is of critical importance. In particular, the curve of the residual energy as a function of the distance travelled in the tissue must be known. In this paper, the results of an experiment carried out with an 241Am source and a series of cryostatic sections of rat-lung tissue are presented. The experimental measurements are compared with the results of Monte Carlo calculations performed with the MCNPX code.

  13. New global loss model of energetic and relativistic electrons based on Van Allen Probes measurements

    NASA Astrophysics Data System (ADS)

    Orlova, Ksenia; Shprits, Yuri; Spasojevic, Maria

    2016-02-01

    The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrument on the Van Allen Probes provides a vast quantity of fully resolved wave measurements below L = 5.5, a critical region for radiation belt acceleration and loss. EMFISIS data show that plasmaspheric hiss waves can be observed at frequencies as low as 20 Hz and provide three-component magnetic field measurements that can be directly used for electron scattering calculations. Updated models of hiss properties based on statistical analysis of Van Allen Probes data were recently developed. We use these new models to compute and parameterize the lifetime of electrons as a function of kinetic energy, L shell, Kp index, and magnetic local time. We present a detailed analysis of the electron lifetime sensitivity to the model of the wave intensity and spectral distribution. We also compare the results with previous models of electron loss, which were based on single-component electric field measurements from the sweep frequency receiver on board the CRRES satellite.

  14. Evolution of Phase Space Sensitivity for Energetic Ion Loss Measurements in DIII-D

    NASA Astrophysics Data System (ADS)

    Cothard, N.; Pace, D. C.

    2014-10-01

    The Fast Ion Loss Detector (FILD) diagnostic system installed on the DIII-D tokamak is a scintillator-based magnetic spectrometer that measures the energy and pitch angle of energetic ions that escape confinement and reach the diagnostic on the outer wall. Different areas of the FILD scintillator correspond to the energies and pitch angles of the impacting ions. This strike map is dependent on the local magnetic field vector that sets the geometry of the ion orbits upon entering the detector. The phase space sensitivity of the FILD, therefore, varies with plasma conditions. The FILD combines a slow camera (100 Hz) viewing the entire scintillator simultaneously with narrow viewing photomultiplier tubes that provide fast time-resolved (1MHz) measurements in narrow bands of energy and pitch angle. New analysis methods allow for tracking the phase space coverage throughout shots, thereby improving the fidelity of ion loss measurements due to plasma instabilities that change in time. Work supported in part by the National Undergraduate Fellowship Program in Plasma Physics and Fusion Energy Sciences and the US Department of Energy under DE-FC02-04ER54698.

  15. Determining material loss from the femoral stem trunnion in hip arthroplasty using a coordinate measuring machine.

    PubMed

    Bone, Martin C; Sidaginamale, Raghavendra P; Lord, James K; Scholes, Susan C; Joyce, Thomas J; Nargol, Anthony V F; Langton, David J

    2015-01-01

    In contrast to the articulating and taper surfaces of failed total hip replacements, volumetric wear analysis of trunnions is not routinely performed. Metal wear particles from the trunnion may contribute not only to the failures of metal-on-metal total hip replacements but also to all hip replacements utilising metal trunnions. A validation study was performed with the material removed in stages from the trunnions of an Exeter V40 stem, a Corail stem and an Accolade stem to simulate different magnitudes of wear. The material loss from the trunnions was measured both volumetrically with a coordinate measuring machine and gravimetrically with a high-precision balance. A cohort of 28 ex vivo trunnions was also measured using the coordinate measuring machine. The maximum error between the two methods was found to be 0.13 mm(3). This result was comparable with the coordinate measuring machine method for the taper surface (0.2 mm(3)). The ex vivo trunnions had a median wear volume of 0.14mm(3) (range: 0.04-0.28 mm(3)). This is the first study to determine the accuracy of volumetric wear measurements of trunnions by comparing against gravimetric measurements. Volumetric wear analysis of trunnions may provide additional insights into failures of modular total hip prostheses and will be performed routinely at our centre. PMID:25655956

  16. The Structure Of Intact Side Tissue Loss Based On FTIR Spectroscopic Measurements

    NASA Astrophysics Data System (ADS)

    Hussain, N.; Al-Hadithi, K. O.; Jaafar, M. S.

    2009-09-01

    Laser applications in dentistry were strongly evolved during the last three decades. Among those applications are laser ablation of dental hard tissue, caries inhibition treatments by localized surface heating, and surface conditioning for bonding. In addition, infra-red lasers are ideally suited for the selective and precise removal of carious dental hard tissue while minimizing the healthy tissue loss. In the present study we applied laser spectroscopy technique FTIR for the study of the structure of intact side tissue of teeth. The aim of the recent work is to study the effect of race and sex (genealogy) on the structure of intact side tissue loss. Our sample consists of twenty Malay females' teeth where the FTIR has been applied. The data show a decrease in the amounts of main substances (like Hydroxyapatite crystals ([Ca5(PO4)3(OH)4], CaF2) than those in healthy teeth. The measured spectra represent the enamel with the characteristic peaks due to the phosphate group in carbonated, hydroxyapatite at 1000 cm-1 and two small peaks near 1500 cm-1 due to the carbonate group. The data explains the effect of the several factors on the intact side tissue loss.

  17. Optical fiber sensor for pressure measurement based on elastomeric membrane and macrobending loss

    NASA Astrophysics Data System (ADS)

    Ribeiro, Livia A.; Rosolem, Joao B.; Dini, Danilo C.; Floridia, Claudio; Bezerra, Edson W.; Cezar, Fabio A.; Loichate, Marcelo D.; Durelli, Anderson S.

    2012-04-01

    We propose a fiber optic sensor array based on bend loss assessed by optical time domain reflectometry (OTDR). The sensor mechanism is based on optical fiber bending loss compressed by external pressure. An elastomeric surface is applied to the sensor in order to communicate external pressure to the fiber coil and also, this make sensor able to deal with degradation coming from aggressive environments. The sensing system proposed is able to monitor liquid or gas pressure in different environments, such as water, oil, alcohols, some diluted acids and others, depending only of elastomeric membrane choice. In order to protect the sensor stage against environmental degradation a plastic packaging was chosen. Bend loss measurements is taken concerning the number of fiber loops involved in the sensor, pump signal wavelength and temporal width. This long for the best parameters in the sensor construction. The specific case of the sensor applied to water percolation monitoring from embankment damns is detailed in this paper; for this application the sensor array have a number of at least six stages totally independent each other, in such a way that each stage can be developed to monitor a specific environment. Sensors have shown good performance in field tests, reaching work range from 0.1 to 0.6 atm with 0.05 atm of precision.

  18. Mass Loss Rates for Solar-like Stars Measured from Lyα Absorption

    NASA Astrophysics Data System (ADS)

    Wood, B. E.; Müller, H.-R.; Linsky, J. L.

    2003-10-01

    We present a number of mass loss rate measurements for solar-like stars with coronal winds, computed using a Lyα absorption technique. The collision between the solar wind and the interstellar wind seen by the Sun defines the large scale structure of our heliosphere. Similar structures, ``astrospheres,'' exist around other solar-like stars. The deceleration of the interstellar wind at the solar or stellar bow shock heats the interstellar material. Heated neutral hydrogen in the outer astrosphere (and/or heliosphere) produces a broad Lyα absorption profile that is often detectable in high resolution Hubble Space Telescope spectra. The amount of absorption is dependent upon the strength of the stellar wind. With guidance from hydrodynamic models of astrospheres, we use detected astrospheric Lyα absorption to estimate the stellar mass loss rates. For the solar-like GK stars in our sample, mass loss appears to increase with stellar activity, suggesting that young, active stars have stronger winds than old, inactive stars. However, Proxima Cen (M5.5 Ve) and λ And (G8 IV-III+M V) appear to be inconsistent with this relation.

  19. Application of transverse microradiography for measurement of mineral loss by acid erosion.

    PubMed

    Hall, A F; Sadler, J P; Strang, R; de Josselin de Jong, E; Foye, R H; Creanor, S L

    1997-11-01

    This paper describes a novel application of transverse microradiography for the detection and quantification of mineral loss due to acid erosion in thin tooth sections. Sixty-four specimens were randomly divided into eight equal-sized groups and exposed to an orthophosphoric-acid-based erosive fluid (pH = 3) for 0, 0.25, 0.5, 1, 2, 5, 12, or 24 hrs. We made microdensitometric scans separately across both enamel and dentin to derive data for the total mineral loss and the minimum mineral content within the eroded area. We then analyzed specimens using a profilometer to determine (1) the area above a plot of penetration depth against distance and (2) the maximum depth of penetration. Correlation coefficients for comparisons between microradiographic and profilometric data for both enamel and dentin specimens varied between 0.87 and 0.96. Two-sample t tests demonstrated that the microradiographic technique could detect early erosion, i.e., discriminate between erosion times of less than 1 hr. It was concluded that this application of transverse microradiography was a useful and acceptable method for the measurement of early mineral loss in vitro, occurring as a result of acid erosion. PMID:9470499

  20. Photothermal measurement of absorption and scattering losses in thin films excited by surface plasmons.

    PubMed

    Domené, Esteban A; Balzarotti, Francisco; Bragas, Andrea V; Martínez, Oscar E

    2009-12-15

    We present a novel noncontact, photothermal technique, based on the focus error signal of a commercial CD pickup head that allows direct determination of absorption in thin films. Combined with extinction methods, this technique yields the scattering contribution to the losses. Surface plasmon polaritons are excited using the Kretschmann configuration in thin Au films of varying thickness. By measuring the extinction and absorption simultaneously, it is shown that dielectric constants and thickness retrieval leads to inconsistencies if the model does not account for scattering. PMID:20016617

  1. Emissivity-corrected power loss calibration for lock-in thermography measurements on silicon solar cells

    NASA Astrophysics Data System (ADS)

    Kasemann, Martin; Walter, Benjamin; Meinhardt, Christoph; Ebser, Jan; Kwapil, Wolfram; Warta, Wilhelm

    2008-06-01

    This paper describes power loss calibration procedures with implemented emissivity correction. The determination of our emissivity correction matrix does neither rely on blackbody reference measurements nor on the knowledge of any sample temperatures. To describe the emissivity-corrected power calibration procedures in detail, we review the theory behind lock-in thermography and show experimentally that the lock-in signal is proportional to the power dissipation in the solar cell. Experiments show the successful application of our emissivity correction procedure, which significantly improves the informative value of lock-in thermography images and the reliability of the conclusions drawn from these images.

  2. Measurements of seepage losses and gains, East Maui Irrigation diversion system, Maui, Hawaiʻi

    USGS Publications Warehouse

    Cheng, Chui Ling

    2012-01-01

    The U.S. Geological Survey conducted a field study from March to October 2011 to identify ditch characteristics and quantify seepage losses and gains in the East Maui Irrigation (EMI) diversion system, east Maui, Hawaiʻi. The EMI diversion system begins at Makapipi Stream in the east and ends at Māliko Gulch in the west. It consists of four primary ditches known as the Wailoa, New Hāmākua, Lowrie, and Haʻikū Ditches. Additional ditches that connect to the four primary ditches include the Koʻolau, Spreckels, Kauhikoa, Spreckels at Pāpaʻaʻea, Manuel Luis, and Center Ditches. Ditch characteristics for about 63 miles of the EMI diversion system, excluding abandoned ditches and stream conveyances, were identified. About 46 miles (73 percent) of the surveyed diversion system are tunnels and 17 miles are open ditches—in which 11 miles are unlined, 3.5 miles are lined, and 2.5 miles are partially lined. The Wailoa, Kauhikoa, and Haʻikū Ditches have greater than 96 percent of their total lengths as tunnels, whereas more than half of the Lowrie Ditch and Spreckels Ditch at Pāpaʻaʻea are open ditches. About 70 percent of the total length of lined open ditches in the EMI diversion system is located along the Koʻolau Ditch, whereas about 67 percent of the total length of unlined open ditches in the diversion system is located along the Lowrie Ditch. Less than 4 percent of the EMI diversion system is partially lined open ditches, and about half of the total partially lined open-ditch length is in the Spreckels Ditch. EMI regularly maintains and repairs the diversion system; therefore, ditch characteristics documented in this report are representative of conditions existing during the period of this study. Discharge measurements were made along 26 seepage-run measurement reaches that are a total of about 15 miles in length. The seepage-run measurement reaches represent 23 percent of the total length of ditches in the EMI diversion system. Discharge measurements

  3. Measurement of submilliwatt, picosecond terahertz emission from a femtosecond-laser-pumped solid-state dc to ac radiation converter based on a ZnSe crystal

    SciTech Connect

    Yugami, Noboru; Ohata, Nobuo; Yaegashi, Kenta; Kawanago, Hiroshi

    2006-11-15

    We measured the terahertz pulse emission from a femtosecond-laser-pumped solid-state dc to ac radiation converter using a 150 fs Ti:sapphire laser pulse for dense plasma diagnostics. The laser-produced ionization front was directly modulated from a periodic electrostatic field to pulsed emission. The central frequency of the emission was measured to be 0.13 THz having a bandwidth of 0.1 THz and a peak power of 0.2 mW. This emission source is suitable for use in various novel diagnostic techniques, such as dense plasma diagnostics.

  4. Performance measurements and operational characteristics of the Storage Tek ACS 4400 tape library with the Cray Y-MP EL

    NASA Technical Reports Server (NTRS)

    Hull, Gary; Ranade, Sanjay

    1993-01-01

    With over 5000 units sold, the Storage Tek Automated Cartridge System (ACS) 4400 tape library is currently the most popular large automated tape library. Based on 3480/90 tape technology, the library is used as the migration device ('nearline' storage) in high-performance mass storage systems. In its maximum configuration, one ACS 4400 tape library houses sixteen 3480/3490 tape drives and is capable of holding approximately 6000 cartridge tapes. The maximum storage capacity of one library using 3480 tapes is 1.2 TB and the advertised aggregate I/O rate is about 24 MB/s. This paper reports on an extensive set of tests designed to accurately assess the performance capabilities and operational characteristics of one STK ACS 4400 tape library holding approximately 5200 cartridge tapes and configured with eight 3480 tape drives. A Cray Y-MP EL2-256 was configured as its host machine. More than 40,000 tape jobs were run in a variety of conditions to gather data in the areas of channel speed characteristics, robotics motion, time taped mounts, and timed tape reads and writes.

  5. Tevatron AC dipole system

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without the emittance growth and decoherence. These properties make it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high power audio amplifier since its operating frequency is approximately 20 kHz. The magnet is incorporated into a parallel resonant system to maximize the current. The use of a vertical pinger magnet which has been installed in the Tevatron made the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-3{sigma} were achieved with the 980 GeV proton beam. This paper discusses details of the Tevatron AC dipole system and also shows its test results.

  6. Measuring grief and loss after spinal cord injury: Development, validation and psychometric characteristics of the SCI-QOL Grief and Loss item bank and short form

    PubMed Central

    Kalpakjian, Claire Z.; Tulsky, David S.; Kisala, Pamela A.; Bombardier, Charles H.

    2015-01-01

    Objective To develop an item response theory (IRT) calibrated Grief and Loss item bank as part of the Spinal Cord Injury – Quality of Life (SCI-QOL) measurement system. Design A literature review guided framework development of grief/loss. New items were created from focus groups. Items were revised based on expert review and patient feedback and were then field tested. Analyses included confirmatory factor analysis (CFA), graded response IRT modeling and evaluation of differential item functioning (DIF). Setting We tested a 20-item pool at several rehabilitation centers across the United States, including the University of Michigan, Kessler Foundation, Rehabilitation Institute of Chicago, the University of Washington, Craig Hospital and the James J. Peters/Bronx Department of Veterans Affairs hospital. Participants A total of 717 individuals with SCI answered the grief and loss questions. Results The final calibrated item bank resulted in 17 retained items. A unidimensional model was observed (CFI = 0.976; RMSEA = 0.078) and measurement precision was good (theta range between −1.48 to 2.48). Ten items were flagged for DIF, however, after examination of effect sizes found this to be negligible with little practical impact on score estimates. Conclusions This study indicates that the SCI-QOL Grief and Loss item bank represents a psychometrically robust measurement tool. Short form items are also suggested and computer adaptive tests are available. PMID:26010969

  7. N-methyl-D-aspartate receptor encephalitis mediates loss of intrinsic activity measured by functional MRI.

    PubMed

    Brier, Matthew R; Day, Gregory S; Snyder, Abraham Z; Tanenbaum, Aaron B; Ances, Beau M

    2016-06-01

    Spontaneous brain activity is required for the development and maintenance of normal brain function. Many disease processes disrupt the organization of intrinsic brain activity, but few pervasively reduce the amplitude of resting state blood oxygen level dependent (BOLD) fMRI fluctuations. We report the case of a female with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, longitudinally studied during the course of her illness to determine the contribution of NMDAR signaling to spontaneous brain activity. Resting state BOLD fMRI was measured at the height of her illness and 18 weeks following discharge from hospital. Conventional resting state networks were defined using established methods. Correlation and covariance matrices were calculated by extracting the BOLD time series from regions of interest and calculating either the correlation or covariance quantity. The intrinsic activity was compared between visits, and to expected activity from 45 similarly aged healthy individuals. Near the height of the illness, the patient exhibited profound loss of consciousness, high-amplitude slowing of the electroencephalogram, and a severe reduction in the amplitude of spontaneous BOLD fMRI fluctuations. The patient's neurological status and measures of intrinsic activity improved following treatment. We conclude that NMDAR-mediated signaling plays a critical role in the mechanisms that give rise to organized spontaneous brain activity. Loss of intrinsic activity is associated with profound disruptions of consciousness and cognition. PMID:27025853

  8. Advantages of a monochromator for bandgap measurements using electron energy-loss spectroscopy.

    PubMed

    Kimoto, Koji; Kothleitner, Gerald; Grogger, Werner; Matsui, Yoshio; Hofer, Ferdinand

    2005-01-01

    The practical advantages of a monochromator for electron energy-loss spectroscopy (EELS) in transmission electron microscopy are reviewed. The zero-loss peaks (ZLPs) of a monochromator and a cold field emission gun are compared in terms of bandgap measurement performance. The intensity of the ZLP tails at the bandgap energy is more important than the full-width at half maximum of the ZLP, and a monochromator is preferable to conventional electron sources. The silicon bandgap of 1.1eV is evaluated from the onset in the EEL spectrum obtained using the monochromator without a numerical procedure. We also show a high-speed instability-correction technique to realize the inherent energy resolution of the monochromator, in which instabilities of less than 335Hz are corrected using 512 EEL spectra obtained with an exposure time of 1.4ms. It will be useful in bandgap measurements and advanced studies for elucidating sub-eV EEL spectra. PMID:15629650

  9. Convective Power Loss Measurements in a Field Reversed Configuration with Rotating Magnetic Field Current Drive

    NASA Astrophysics Data System (ADS)

    Melnik, Paul

    The Translation, Confinement, and Sustainment Upgrade (TCSU) experiment achieves direct formation and sustainment of a field reversed configuration (FRC) plasma through rotating magnetic fields (RMF). The pre-ionized gas necessary for FRC formation is supplied by a magnetized cascade arc source that has been developed for TCSU. To ensure ideal FRC performance, the condition of the vacuum chamber prior to RMF start-up has been characterized with the use of a fast response ion gauge. A circuit capable of gating the puff valves with initial high voltage for quick response and then indefinite operational voltage was also designed. A fully translatable combination Langmuir / Mach probe was also built to measure the electron temperature, electron density, and ion velocity of the FRC. These measurements were also successfully completed in the FRC exhaust jets allowing for an accurate analysis of the FRC power loss through convection.

  10. Loss of interpretability due to compression effects as measured by the new video NIIRS

    NASA Astrophysics Data System (ADS)

    Young, Darrell; Bakir, Tariq; Butto, Robert, Jr.; Duffield, Charles; Petitti, Fred

    2010-01-01

    The effect of video compression is examined using the task-based performance metrics of the new Video National Intelligence Interpretability Rating Scale (Video NIIRS). Video NIIRS is a subjective task criteria scale similar to the well-known Visible NIIRS used for still image quality measurement. However, each task in the Video NIIRS includes a dynamic component that requires video of sufficient spatial and temporal resolution. The loss of Video NIIRS due to compression is experimentally measured for select cases. The results show that an increase in the compression and an associated increase in artifacts reduces task based interpretability and lowers the Video-NIIRS rating of the video clips. The extent of the effect has implications for system design.

  11. Quantitative Estimation of the Metal-Induced Negative Oxide Charge Density in n-Type Silicon Wafers from Measurements of Frequency-Dependent AC Surface Photovoltage

    NASA Astrophysics Data System (ADS)

    Shimizu, Hirofumi; Shin, Ryuhei; Ikeda, Masanori

    2006-03-01

    A quantitative estimation of metal-induced oxide charge (Qmi) density is performed on the surface of n-type silicon (Si) wafers rinsed with trivalent aluminum (Al)- and iron (Fe)-contaminated RCA alkaline solution by analyzing the frequency-dependent AC surface photovoltage (SPV). Qmi arises from (AlOSi)- or (FeOSi)- networks in native oxide which are responsible for inducing negative oxide charge. On the basis of Munakata and Nishimatsu’s half-sided junction model [C. Munakata and S. Nishimatsu: Jpn. J. Appl. Phys. 25 (1986) 807], the network densities are estimated in depletion and/or weak inversion in which the cutoff frequencies of the frequency-dependent AC SPV curves are defined. It is found that the charge density Qmi increases with the time of exposure to air and it is calculated that about 4% of Al atoms in the native oxide are activated in the form of an (AlOSi)- network for 1 h of exposure. The (FeOSi)- network density is calculated as a function of Fe concentration. As a result, the frequency-dependent AC SPV measurements carried out here enable a successful evaluation of impurity level in a nondestructive and noncontact manner.

  12. An analysis method for transmission measurements of superconducting resonators with applications to quantum-regime dielectric-loss measurements

    NASA Astrophysics Data System (ADS)

    Deng, Chunqing; Otto, Martin; Lupascu, Adrian

    2013-08-01

    Superconducting resonators provide a convenient way to measure loss tangents of various dielectrics at low temperature. For the purpose of examining the microscopic loss mechanisms in dielectrics, precise measurements of the internal quality factor at different values of energy stored in the resonators are required. Here, we present a consistent method to analyze a LC superconducting resonator coupled to a transmission line. We first derive an approximate expression for the transmission S-parameter S21(ω), with ω the excitation frequency, based on a complete circuit model. In the weak coupling limit, we show that the internal quality factor is reliably determined by fitting the approximate form of S21(ω). Since the voltage V of the capacitor of the LC circuit is required to determine the energy stored in the resonator, we next calculate the relation between V and the forward propagating wave voltage Vin+, with the latter being the parameter controlled in experiments. Due to the dependence of the quality factor on voltage, V is not simply proportional to Vin+. We find a self-consistent way to determine the relation between V and Vin+, which employs only the fitting parameters for S21(ω) and a linear scaling factor. We then examine the resonator transmission in the cases of port reflection and impedance mismatch. We find that resonator transmission asymmetry is primarily due to the reflection from discontinuity in transmission lines. We show that our analysis method to extract the internal quality factor is robust in the non-ideal cases above. Finally, we show that the analysis method used for the LC resonator can be generalized to arbitrary weakly coupled lumped and distributed resonators. The generalization uses a systematic approximation on the response function based on the pole and zero which are closest to the resonance frequency. This Closest Pole and Zero Method is a valuable tool for analyzing physical measurements of high-Q resonators.

  13. Low-frequency losses at high fields in multifilamentary superconductors

    SciTech Connect

    Zaleski, A.J.; Orlando, T.P.; Zieba, A.; Schwartz, B.B.; Foner, S.

    1984-12-01

    Low-frequency (approx.1 Hz) ac loss measurements were made at applied fields up to 20 T with field modulation amplitudes of up to 1 T. Results for the alternative in situ and powder metallurgy (P/M) processed Nb/sub 3/Sn and Nb--Al wires are presented for single-strand and multistrand geometries. Loss measurements for commercial continuous-fiber Nb/sub 3/Sn wires manufactured by Holec and Supercon also are presented and show that the effective fiber size determined by these ac-loss measurements corresponds to that measured optically. The effective fiber size for alternative processed wires was intermediate between the wire size and the fiber size, and the losses (and effective fiber size) were reduced by twisting. Multistrand geometries showed further reductions in losses. The smallest effective fiber size at high field was measured for P/M processed Nb--Al. The losses were fully hysteretic and the ac losses were used to determine the critical-current density at low fields where it was difficult to measure directly.

  14. The Learning Loss Scale as an Assessment Tool: An Empirical Examination of Convergent Validity with Performative Measures

    ERIC Educational Resources Information Center

    Hooker, John; Denker, Katherine

    2014-01-01

    Higher education has placed an increasingly greater value on assessment. The Learning Loss Scale may be an appropriate tool to assess learning across disciplines. In this paper, we review the culture of assessment, conceptualizations of cognitive learning, the Learning Loss Scale, and a theoretical explanation, and then we test this measure to…

  15. On the reliable measurement of specific absorption rates and intrinsic loss parameters in magnetic hyperthermia materials

    NASA Astrophysics Data System (ADS)

    Wildeboer, R. R.; Southern, P.; Pankhurst, Q. A.

    2014-12-01

    In the clinical application of magnetic hyperthermia, the heat generated by magnetic nanoparticles in an alternating magnetic field is used as a cancer treatment. The heating ability of the particles is quantified by the specific absorption rate (SAR), an extrinsic parameter based on the clinical response characteristic of power delivered per unit mass, and by the intrinsic loss parameter (ILP), an intrinsic parameter based on the heating capacity of the material. Even though both the SAR and ILP are widely used as comparative design parameters, they are almost always measured in non-adiabatic systems that make accurate measurements difficult. We present here the results of a systematic review of measurement methods for both SAR and ILP, leading to recommendations for a standardised, simple and reliable method for measurements using non-adiabatic systems. In a representative survey of 50 retrieved datasets taken from published papers, the derived SAR or ILP was found to be more than 5% overestimated in 24% of cases and more than 5% underestimated in 52% of cases.

  16. Mass loss

    NASA Technical Reports Server (NTRS)

    Goldberg, Leo

    1987-01-01

    Observational evidence for mass loss from cool stars is reviewed. Spectra line profiles are used for the derivation of mass-loss rates with the aid of the equation of continuity. This equation implies steady mass loss with spherical symmetry. Data from binary stars, Mira variables, and red giants in globular clusters are examined. Silicate emission is discussed as a useful indicator of mass loss in the middle infrared spectra. The use of thermal millimeter-wave radiation, Very Large Array (VLA) measurement of radio emission, and OH/IR masers are discussed as a tool for mass loss measurement. Evidence for nonsteady mass loss is also reviewed.

  17. Two-channel method for measuring losses in a ring optical resonator at a wavelength of 632.8 nm

    NASA Astrophysics Data System (ADS)

    Azarova, V. V.; Bessonov, A. S.; Bondarev, A. L.; Makeev, A. P.; Petrukhin, E. A.

    2016-07-01

    A two-channel method is proposed for measuring losses in an optical ring resonator (RR), in which eigenmodes (counterpropagating waves) are excited by means of a Zeeman ring He – Ne laser with a wavelength of 632.8 nm. The measured frequency splitting of the laser counterpropgating waves is used to determine the absolute value of losses in an exemplary RR. The value of losses in the measured RR is determined by comparing the resonance width of the output radiation intensity with the resonance width of the radiation intensity for an exemplary resonator. The algorithm of intensity resonance processing takes into account the distortions caused by the dynamic effect, which allows a significant increase in the accuracy (up to 1% – 2%) and sensitivity of the proposed method. The measured losses in the RR with a perimeter of 28 cm constitute 80 – 5000 ppm.

  18. Self-consistent magnetic properties of magnetite tracers optimized for magnetic particle imaging measured by ac susceptometry, magnetorelaxometry and magnetic particle spectroscopy

    PubMed Central

    Ludwig, Frank; Remmer, Hilke; Kuhlmann, Christian; Wawrzik, Thilo; Arami, Hamed; Ferguson, R. Mathew; Krishnan, Kannan M.

    2015-01-01

    Sensitivity and spatial resolution in Magnetic Particle Imaging are affected by magnetic properties of the nanoparticle tracers used during imaging. Here, we have carried out a comprehensive magnetic characterization of single-core iron oxide nanoparticles that were designed for MPI. We used ac susceptometry, fluxgate magnetorelaxometry, and magnetic particle spectroscopy to evaluate the tracer’s magnetic core size, hydrodynamic size, and magnetic anisotropy. Our results present a self-consistent set of magnetic and structural parameters for the tracers that is consistent with direct measurements of size using transmission electron microscopy and dynamic light scattering and that can be used to better understand their MPI performance. PMID:25729125

  19. Self-consistent magnetic properties of magnetite tracers optimized for magnetic particle imaging measured by ac susceptometry, magnetorelaxometry and magnetic particle spectroscopy

    NASA Astrophysics Data System (ADS)

    Ludwig, Frank; Remmer, Hilke; Kuhlmann, Christian; Wawrzik, Thilo; Arami, Hamed; Ferguson, R. Mathew; Krishnan, Kannan M.

    2014-06-01

    Sensitivity and spatial resolution in magnetic particle imaging are affected by magnetic properties of the nanoparticle tracers used during imaging. Here, we have carried out a comprehensive magnetic characterization of single-core iron oxide nanoparticles that were designed for MPI. We used ac susceptometry, fluxgate magnetorelaxometry, and magnetic particle spectroscopy to evaluate the tracer's magnetic core size, hydrodynamic size, and magnetic anisotropy. Our results present a self-consistent set of magnetic and structural parameters for the tracers that is consistent with direct measurements of size using transmission electron microscopy and dynamic light scattering and that can be used to better understand their MPI performance.

  20. In-Situ Measurement of Power Loss for Crystalline Silicon Modules Undergoing Thermal Cycling and Mechanical Loading Stress Testing: Preprint

    SciTech Connect

    Spataru, Sergiu; Hacke, Pater; Sera, Dezso

    2015-09-15

    We analyze the degradation of multi-crystalline silicon photovoltaic modules undergoing simultaneous thermal, mechanical, and humidity stress testing to develop a dark environmental chamber in-situ measurement procedure for determining module power loss. From the analysis we determine three main categories of failure modes associated with the module degradation consisting of: shunting, recombination losses, increased series resistance losses, and current mismatch losses associated with a decrease in photo-current generation by removal of some cell areas due to cell fractures. Based on the analysis, we propose an in-situ module power loss monitoring procedure that relies on dark current-voltage measurements taken during the stress test, and initial and final module flash testing, to determine the power degradation characteristic of the module.

  1. Measurement of mechanical loss in the Acktar Black coating of silicon wafers

    NASA Astrophysics Data System (ADS)

    Abernathy, M. R.; Smith, N.; Korth, W. Z.; Adhikari, R. X.; Prokhorov, L. G.; Koptsov, D. V.; Mitrofanov, V. P.

    2016-09-01

    Some proposed interferometric gravitational wave detectors of the next generation are designed to use silicon test masses cooled to cryogenic temperatures. The test masses will need to be partially coated with high emissivity coating to provide sufficient cooling when they absorb the laser light. The mechanical loss of the Acktar Black coating is determined based on the measurements of the Q-factors of the bending vibration modes of coated and uncoated commercial silicon wafers. The Young's modulus of the coating material is determined using nanoindentation. We use this information to calculate thermal noise of the silicon test masses associated with a high emissivity coating on its lateral side (barrel). It is found that such a coating results in a less than 9% increase of the total strain noise of LIGO Voyager design for a future cryogenic gravitational wave detector.

  2. How Many Measurements Are Needed to Estimate Blood Pressure Variability Without Loss of Prognostic Information?

    PubMed Central

    2014-01-01

    BACKGROUND Average real variability (ARV) is a recently proposed index for short-term blood pressure (BP) variability. We aimed to determine the minimum number of BP readings required to compute ARV without loss of prognostic information. METHODS ARV was calculated from a discovery dataset that included 24-hour ambulatory BP measurements for 1,254 residents (mean age = 56.6 years; 43.5% women) of Copenhagen, Denmark. Concordance between ARV from full (≥80 BP readings) and randomly reduced 24-hour BP recordings was examined, as was prognostic accuracy. A test dataset that included 5,353 subjects (mean age = 54.0 years; 45.6% women) with at least 48 BP measurements from 11 randomly recruited population cohorts was used to validate the results. RESULTS In the discovery dataset, a minimum of 48 BP readings allowed an accurate assessment of the association between cardiovascular risk and ARV. In the test dataset, over 10.2 years (median), 806 participants died (335 cardiovascular deaths, 206 cardiac deaths) and 696 experienced a major fatal or nonfatal cardiovascular event. Standardized multivariable-adjusted hazard ratios (HRs) were computed for associations between outcome and BP variability. Higher diastolic ARV in 24-hour ambulatory BP recordings predicted (P < 0.01) total (HR = 1.12), cardiovascular (HR = 1.19), and cardiac (HR = 1.19) mortality and fatal combined with nonfatal cerebrovascular events (HR = 1.16). Higher systolic ARV in 24-hour ambulatory BP recordings predicted (P < 0.01) total (HR = 1.12), cardiovascular (HR = 1.17), and cardiac (HR = 1.24) mortality. CONCLUSIONS Forty-eight BP readings over 24 hours were observed to be adequate to compute ARV without meaningful loss of prognostic information. PMID:23955605

  3. A Control Based System of Mechanical Loss Measurement for High Quality Factor Oscillators

    NASA Astrophysics Data System (ADS)

    Louis Gitelman, Louis; Smith, Nicolas; Jafar, Isaac; Harry, Gregory; Newport, Jonathan; Abernathy, Matt; LIGO Collaboration

    In this poster we will present the control system being developed to measure the quality factor of optics used in the Advanced LIGO gravitational wave detectors to predict thermal noise levels. It works by locking the phase between the optic's exciter and normal mode to pi/2 and locking the optics's amplitude allowing one to equate the energy output of the exciter to the mechanical loss of the optic. To do this the amplitude of the normal mode is detected using a birefringence meter and lockin amplifier, which is then fedback to an electrostatic exciter to control the mode's amplitude and phase with a PID controller written on a python script. The poster will discuss the components and assembly of this system and the theoretical control structure behind it. It will also discuss the speed, accuracy and general feasibility of this method of quality factor measurement relative to other methods, and steps to improve and develop this method of quality factor measurement and the possible applications for LIGO and in general.

  4. Magnetization losses in superconducting YBCO conductor-on-round-core (CORC) cables

    NASA Astrophysics Data System (ADS)

    Majoros, M.; Sumption, M. D.; Collings, E. W.; van der Laan, D. C.

    2014-12-01

    Described are the results of magnetization loss measurements made at 77 K on several YBCO conductor-on-round-core (CORC) cables in ac magnetic fields of up to 80 mT in amplitude and frequencies of 50 to 200 Hz, applied perpendicular to the cable axis. The cables contained up to 40 tapes that were wound in as many as 13 layers. Measurements on the cables with different configurations were made as functions of applied ac field amplitude and frequency to determine the effects of their layout on ac loss. In large scale devices such as e.g. Superconducting Magnetic Energy Storage (SMES) magnets, the observed ac losses represent less than 0.1% of their stored energy.

  5. Energy saving in ac generators

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1980-01-01

    Circuit cuts no-load losses, without sacrificing full-load power. Phase-contro circuit includes gate-controlled semiconductor switch that cuts off applied voltage for most of ac cycle if generator idling. Switch "on" time increases when generator is in operation.

  6. The Relationship between Measures of Hearing Loss and Speech Intelligibility in Young Deaf Children.

    ERIC Educational Resources Information Center

    Musselman, Carol Reich

    1990-01-01

    This study of 121 young deaf children identified 3 distinct groups: children with losses of 70-89 decibels developed some intelligible speech, children with losses of 90-104 decibels exhibited considerable variability, and children with losses above 105 decibels developed little intelligible speech. The unaided hearing threshold level was the best…

  7. MSL/SAM Measurements of Volatile Isotopes, and their Implications for Atmospheric Loss

    NASA Astrophysics Data System (ADS)

    Atreya, Sushil K.; Mahaffy, Paul; Webster, Christopher; Wong, Michael; Conrad, Pamela; Franz, Heather; Grotzinger, John; Jones, John; Leshin, Laurie; Malespin, Charles; Manning, Heidi; Navarro-Gonzalez, Raphael; Owen, Tobias; Pepin, Robert; Schwenzer, Susanne; Trainer, Melissa

    2014-05-01

    High precision measurements of the isotopes of carbon and oxygen in CO2, hydrogen in H2O, nitrogen in N2, and argon in the martian atmosphere have been made by the Sample Analysis at Mars (SAM) instrument on the Curiosity Rover [1,2,3,4]. The resulting values in per mil are 46 for δ13C (relative to VPDB reference standard), 48 for δ18O (VSMOW), 5880 for δD (VSMOW), 572 for δ15N (relative to earth atmosphere), and 4.2 for 36Ar/38Ar (or δ38Ar=310 relative to sun reference standard). The observed enrichment of the heavier isotope over the lighter isotope means that loss to space rather than loss to the surface dominates the isotopic composition in the martian atmosphere. Vertical mixing transports the volatiles from the surface up to the upper atmosphere. While eddy diffusion and molecular diffusion control the distribution of the noble gases, photochemistry also plays a significant role in the distribution of the other volatiles as they diffuse to the upper atmosphere. The above SAM data on the isotopic ratios of carbon, oxygen, hydrogen, nitrogen and argon implies a massive loss of the atmosphere from Mars in the past four billion years. Only hydrogen (hence water) is likely to escape thermally due to the low exospheric temperature of Mars. However, the lack of intrinsic magnetic field on Mars allows solar wind to interact directly with the atmosphere, thus opening up a myriad of possibilities for escape of volatiles from Mars. One such mechanism studied by the ion mass analyzer instrument on Mars Express finds that at current rate of erosion by solar wind, Mars may have lost between 0.2 and 4 millibar of the CO2 atmosphere in the past 3.5 billion years [5]. However, these authors [5] stress that other mechanisms including photochemical, sputtering and cold plasma escape may result in up to 1000 times greater rate of atmospheric loss based on models. Any fractionation in the isotopes of the heavy noble gas, xenon, would have occurred prior to approximately 4 Ga

  8. The Cardiomyopathy Lamin A/C D192G Mutation Disrupts Whole-Cell Biomechanics in Cardiomyocytes as Measured by Atomic Force Microscopy Loading-Unloading Curve Analysis

    PubMed Central

    Lanzicher, Thomas; Martinelli, Valentina; Puzzi, Luca; Del Favero, Giorgia; Codan, Barbara; Long, Carlin S.; Mestroni, Luisa; Taylor, Matthew R. G.; Sbaizero, Orfeo

    2015-01-01

    Atomic force microscopy (AFM) cell loading/unloading curves were used to provide comprehensive insights into biomechanical behavior of cardiomyocytes carrying the lamin A/C (LMNA) D192G mutation known to cause defective nuclear wall, myopathy and severe cardiomyopathy. Our results suggested that the LMNA D192G mutation increased maximum nuclear deformation load, nuclear stiffness and fragility as compared to controls. Furthermore, there seems to be a connection between this lamin nuclear mutation and cell adhesion behavior since LMNA D192G cardiomyocytes displayed loss of AFM probe-to-cell membrane adhesion. We believe that this loss of adhesion involves the cytoskeletal architecture since our microscopic analyses highlighted that mutant LMNA may also lead to a morphological alteration in the cytoskeleton. Furthermore, chemical disruption of the actin cytoskeleton by cytochalasin D in control cardiomyocytes mirrored the alterations in the mechanical properties seen in mutant cells, suggesting a defect in the connection between the nucleoskeleton, cytoskeleton and cell adhesion molecules in cells expressing the mutant protein. These data add to our understanding of potential mechanisms responsible for this fatal cardiomyopathy, and show that the biomechanical effects of mutant lamin extend beyond nuclear mechanics to include interference of whole-cell biomechanical properties. PMID:26323789

  9. Application of independent component analysis to ac dipole based optics measurement and correction at the Relativistic Heavy Ion Collider

    NASA Astrophysics Data System (ADS)

    Shen, X.; Lee, S. Y.; Bai, M.; White, S.; Robert-Demolaize, G.; Luo, Y.; Marusic, A.; Tomás, R.

    2013-11-01

    Correction of beta-beat is of great importance for performance improvement of high energy accelerators, like the Relativistic Hadron Ion Collider (RHIC). At RHIC, using the independent component analysis method, linear optical functions are extracted from the turn by turn beam position data of the ac dipole driven betatron oscillation. Despite the constraint of a limited number of available quadrupole correctors at RHIC, a global beta-beat correction scheme using a beta-beat response matrix method was developed and experimentally demonstrated. In both rings, a factor of 2 or better reduction of beta-beat was achieved within available beam time. At the same time, a new scheme of using horizontal closed orbit bump at sextupoles to correct beta-beat in the arcs was demonstrated in the Yellow ring of RHIC at beam energy of 255 GeV, and a peak beta-beat of approximately 7% was achieved.

  10. Electric characterization of (Sr, Sr-Ba, Ba) M-type ferrites by AC measurements[Alternating Current

    SciTech Connect

    Huanosta-Tera, A.; Lira-Hueso, R. de; Perez-Orta, O.; Palomares-Sanchez, S.A.; Ponce-Castaneda, S.; Mirabal-Garcia, M.

    2000-02-01

    Considering the electrical conductivity in ceramics, necessary reference should be given to dynamic processes occurring as a function of frequency and temperature. Although the most immediate interest in ferrites lies in their magnetic properties, technological applications require a wider knowledge of general physical properties as well. This is especially applicable when the materials are studied as a function of composition or when adding different modifiers. In this report, the authors present results of the ac and dc electric characteristics of a family of magneto-plumbite-type hexaferrites, where Ba gradually substitutes Sr in the Ba{sub x}Sr{sub 1{minus}x}Fe{sub 12}O{sub 19} compound (0 {le} x {le} 1). The results were determined over a wide range of frequencies and temperatures.

  11. Radiative Heat Loss Measurements During Microgravity Droplet Combustion in a Slow Convective Flow

    NASA Technical Reports Server (NTRS)

    Hicks, Michael C.; Kaib, Nathan; Easton, John; Nayagam, Vedha; Williams, Forman A.

    2003-01-01

    Radiative heat loss from burning droplets in a slow convective flow under microgravity conditions is measured using a broad-band (0.6 to 40 microns) radiometer. In addition, backlit images of the droplet as well as color images of the flame were obtained using CCD cameras to estimate the burning rates and the flame dimensions, respectively. Tests were carried out in air at atmospheric pressure using n-heptane and methanol fuels with imposed forced flow velocities varied from 0 to 10 centimeters per second and initial droplet diameters varied from 1 to 3 millimeters. Slow convective flows were generated using three different experimental configurations in three different facilities in preparation for the proposed International Space Station droplet experiments. In the 2.2 Second Drop-Tower Facility a droplet supported on the leading edge of a quartz fiber is placed within a flow tunnel supplied by compressed air. In the Zero-Gravity Facility (five-second drop tower) a tethered droplet is translated in a quiescent ambient atmosphere to establish a uniform flow field around the droplet. In the KC 135 aircraft an electric fan was used to draw a uniform flow past a tethered droplet. Experimental results show that the burn rate increases and the overall flame size decreases with increases in forced-flow velocities over the range of flow velocities and droplet sizes tested. The total radiative heat loss rate, Q(sub r), decreases as the imposed flow velocity increases with the spherically symmetric combustion having the highest values. These observations are in contrast to the trends observed for gas-jet flames in microgravity, but consistent with the observations during flame spread over solid fuels where the burning rate is coupled to the forced flow as here.

  12. Modeling and measurement of losses in silicon-on-insulator resonators and bends.

    PubMed

    Xiao, Shijun; Khan, Maroof H; Shen, Hao; Qi, Minghao

    2007-08-20

    We present an analytical model to quantify losses in resonators and bends without uncertain contributions from fiber coupling in/out or waveguide cleavage facets. With resonators in add-drop configuration, intrinsic losses are calculated from the free spectral range, through-port extinction and drop-port bandwidth. We fabricated and characterized silicon-on-insulator resonator for loss analysis. At 1.55 mum, racetrack resonators with a bending radius of 4.5 mum show intrinsic losses as small as 0.14+/-0.014 dB/round-trip. Meanwhile, intrinsic losses increase up to 1.23 dB/round-trip in the racetrack resonator that has a bending radius of 2.25 mum. Losses in a 180 degrees bend are estimated as a half of the intrinsic losses in these racetrack resonators, i.e., 0.07+/-0.007 dB/turn for a bending radius of 4.5 mum and 0.62 dB/turn for a bending radius of 2.25 mum. Loss in a 90 degrees bend with a radius of 4.5 mum is determined to be 0.06+/-0.006 dB/turn at 1.55 mum. The losses in 180 degrees or 90 degrees bends are found to be mainly due to the transition loss between waveguide bends and straight waveguides. PMID:19547408

  13. ac Stark shift measurements of the clock transition in cold Cs atoms: Scalar and tensor light shifts of the D2 transition

    NASA Astrophysics Data System (ADS)

    Costanzo, G. A.; Micalizio, S.; Godone, A.; Camparo, J. C.; Levi, F.

    2016-06-01

    The ac Stark shift, or light shift, is a physical phenomenon that plays a fundamental role in many applications ranging from basic atomic physics to applied quantum electronics. Here, we discuss experiments testing light-shift theory in a cold-atom cesium fountain clock for the Cs D2 transition (i.e., 6 2S1 /2→6 2P3 /2 at 852 nm). Cold-atom fountains represent a nearly ideal system for the study of light shifts: (1) The atoms can be perturbed by a field of arbitrary character (e.g., coherent field or nonclassical field); (2) there are no trapping fields to complicate data interpretation; (3) the probed atoms are essentially motionless in their center-of-mass reference frame, T ˜ 1 μK; and (4) the atoms are in an essentially collisionless environment. Moreover, in the present work the resolution of the Cs excited-state hyperfine splittings implies that the D2 ac Stark shift contains a nonzero tensor polarizability contribution, which does not appear in vapor phase experiments due to Doppler broadening. Here, we test the linearity of the ac Stark shift with field intensity, and measure the light shift as a function of field frequency, generating a "light-shift curve." We have improved on the previous best test of theory by a factor of 2, and after subtracting the theoretical scalar light shift from the experimental light-shift curves, we have isolated and tested the tensor light shift for an alkali D2 transition.

  14. Charge Loss and Charge Sharing Measurements for Two Different Pixelated Cadmium-Zinc-Telluride Detectors

    NASA Technical Reports Server (NTRS)

    Gaskin, Jessica; Sharma, Dharma; Ramsey, Brian; Seller, Paul

    2003-01-01

    As part of ongoing research at Marshall Space Flight Center, Cadmium-Zinc- Telluride (CdZnTe) pixilated detectors are being developed for use at the focal plane of the High Energy Replicated Optics (HERO) telescope. HERO requires a 64x64 pixel array with a spatial resolution of around 200 microns (with a 6m focal length) and high energy resolution (< 2% at 60keV). We are currently testing smaller arrays as a necessary first step towards this goal. In this presentation, we compare charge sharing and charge loss measurements between two devices that differ both electronically and geometrically. The first device consists of a 1-mm-thick piece of CdZnTe that is sputtered with a 4x4 array of pixels with pixel pitch of 750 microns (inter-pixel gap is 100 microns). The signal is read out using discrete ultra-low-noise preamplifiers, one for each of the 16 pixels. The second detector consists of a 2-mm-thick piece of CdZnTe that is sputtered with a 16x16 array of pixels with a pixel pitch of 300 microns (inter-pixel gap is 50 microns). Instead of using discrete preamplifiers, the crystal is bonded to an ASIC that provides all of the front-end electronics to each of the 256 pixels. what degree the bias voltage (i.e. the electric field) and hence the drift and diffusion coefficients affect our measurements. Further, we compare the measured results with simulated results and discuss to

  15. Structural, AC conductivity and dielectric properties of Sr-La hexaferrite

    NASA Astrophysics Data System (ADS)

    Singh, A.; Narang, S. B.; Singh, K.; Sharma, P.; Pandey, O. P.

    2006-03-01

    A series of M-type hexaferrite samples with composition Sr{1-x}La{x}Fe{12}O{19} (x = 0.00, 0.05, 0.15 and 0.25) were prepared by standard ceramic technique. AC electrical conductivity measurements were carried out at different frequencies (20 Hz 1 MHz) and at different temperatures. The dielectric constant and dielectric loss tangent were measured in the same range of frequencies. The experimental results indicate that AC electrical conductivity increases on increasing the frequency as well as the temperature, indicating magnetic semiconductor behavior of the samples. The increase in AC electrical conductivity with frequency and temperature has been explained on the basis of Koops Model whereas dielectric constant and dielectric loss tangent has been explained with the Maxwell Wagner type interfacial polarization in agreement with the Koops phenomenological theory.

  16. AC photovoltaic module magnetic fields

    SciTech Connect

    Jennings, C.; Chang, G.J.; Reyes, A.B.; Whitaker, C.M.

    1997-12-31

    Implementation of alternating current (AC) photovoltaic (PV) modules, particularly for distributed applications such as PV rooftops and facades, may be slowed by public concern about electric and magnetic fields (EMF). This paper documents magnetic field measurements on an AC PV module, complementing EMF research on direct-current PV modules conducted by PG and E in 1993. Although not comprehensive, the PV EMF data indicate that 60 Hz magnetic fields (the EMF type of greatest public concern) from PV modules are comparable to, or significantly less than, those from household appliances. Given the present EMF research knowledge, AC PV module EMF may not merit considerable concern.

  17. Measurement of transmission loss characteristics using acoustic intensity techniques at the KU-FRL Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Roskam, J.

    1983-01-01

    The transmission loss characteristics of panels using the acoustic intensity technique is presented. The theoretical formulation, installation of hardware, modifications to the test facility, and development of computer programs and test procedures are described. A listing of all the programs is also provided. The initial test results indicate that the acoustic intensity technique is easily adapted to measure transmission loss characteristics of panels. Use of this method will give average transmission loss values. The fixtures developed to position the microphones along the grid points are very useful in plotting the intensity maps of vibrating panels.

  18. Direct measurement of laser-induced frequency shift rate of ultracold cesium molecules by analyzing losses of trapped atoms

    SciTech Connect

    Zhang Yichi; Ma Jie; Li Yuqing; Wu Jizhou; Zhang Linjie; Chen Gang; Wang Lirong; Zhao Yanting; Xiao Liantuan; Jia Suotang

    2012-09-24

    We report on a quantitative experimental determination of the laser-induced frequency shift rate of the ultracold cesium molecules formed via photoassociation (PA) by means of the trap loss measurement of the losses of trapped atoms in a standard magneto-optical trap. The experiment was directly performed by varying the photoassociation laser intensity without any additional frequency monitor technologies. Our experimental method utilized dependences of the losses on the laser-induced frequency shift rate based on the conditions of the identified photoassociation spectral shape. We demonstrated that the method is sensitive enough to determine small frequency shifts of rovibrational levels of ultracold cesium molecules.

  19. A cluster-glass magnetic state in R5Pd2 (R = Ho, Tb) compounds evidenced by AC-susceptibility and neutron scattering measurements.

    PubMed

    Gubkin, A F; Sherstobitova, E A; Terentyev, P B; Hoser, A; Baranov, N V

    2013-06-12

    AC- and DC-susceptibility, high-field magnetization and neutron diffraction measurements have been performed in order to study the magnetic state of R5Pd2 (R = Ho, Tb) compounds. The results show that both compounds undergo cluster-glass freezing upon cooling below Tf. According to the neutron diffraction a long-range magnetic order is absent down to 2 K and magnetic clusters with short-range incommensurate antiferromagnetic correlations exist not only below Tf but also in a wide temperature range above the freezing temperature (at least up to 2Tf). A complex cluster-glass magnetic state existing in Ho5Pd2 and Tb5Pd2 down to low temperatures results in rather complicated magnetization behavior in DC and AC magnetic fields. Such an unusual magnetic state in compounds with a high rare-earth concentration may be associated with the layered type of their crystal structure and with substantial atomic disorder, which results in frustrations in the magnetic subsystem. PMID:23676314

  20. Measurement of the Loss and Depolarization Probability of UCN on Beryllium and Diamond Like Carbon Films

    PubMed Central

    Brys, Tomas; Daum, Manfred; Fierlinger, Peter; Geltenbort, Peter; Gupta, Mukul; Henneck, Reinhold; Heule, Stefan; Kirch, Klaus; Lasakov, Mikhail; Mammei, Russel; Makela, Mark; Pichlmaier, Axel; Serebrov, Anatoli; Straumann, Ulrich; Vogelaar, Robert B.; Wermelinger, Cedric; Young, Albert

    2005-01-01

    Currently several institutes worldwide are working on the development of a new generation of ultracold neutron (UCN) sources. In parallel with source development, new materials for guiding and storage of UCN are developed. Currently the best results have been achieved using 58Ni, Be, solid O2 and low temperature Fomblin oil (LTF). All of these materials have their shortcomings like cost, toxicity or difficulty of use. A novel very promising material is diamond like carbon (DLC). Several techniques exist to coat surfaces, and industrial applications (e.g., for extremely hard surfaces) are already wide spread. Preliminary investigations using neutron reflectometry at PSI and Los Alamos yielded a critical velocity for DLC of about 7 m/s thus comparable to Beryllium. A low upper limit of depolarization probability for stored polarized UCN has been measured at the PF2 facility of the Institut Laue-Langevin (ILL) by North Carolina State University (NCSU), Los Alamos National Laboratory (LANL), and Petersburg Nuclear Physics Institute (PNPI), thus making it also a good material for storage and guidance of polarized UCN. Still missing is the loss probability per bounce. We will be able to extract this number and a more stringent value for the depolarization from our experiment thus proving the suitability of DLC as a wall material for a wide range of UCN applications. PMID:27308136

  1. GRACE, GLDAS and measured groundwater data products show water storage loss in Western Jilin, China.

    PubMed

    Moiwo, Juana Paul; Lu, Wenxi; Tao, Fulu

    2012-01-01

    Water storage depletion is a worsening hydrological problem that limits agricultural production in especially arid/semi-arid regions across the globe. Quantifying water storage dynamics is critical for developing water resources management strategies that are sustainable and protective of the environment. This study uses GRACE (Gravity Recovery and Climate Experiment), GLDAS (Global Land Data Assimilation System) and measured groundwater data products to quantify water storage in Western Jilin (a proxy for semi-arid wetland ecosystems) for the period from January 2002 to December 2009. Uncertainty/bias analysis shows that the data products have an average error <10% (p < 0.05). Comparisons of the storage variables show favorable agreements at various temporal cycles, with R(2) = 0.92 and RMSE = 7.43 mm at the average seasonal cycle. There is a narrowing soil moisture storage change, a widening groundwater storage loss, and an overall storage depletion of 0.85 mm/month in the region. There is possible soil-pore collapse, and land subsidence due to storage depletion in the study area. Invariably, storage depletion in this semi-arid region could have negative implications for agriculture, valuable/fragile wetland ecosystems and people's livelihoods. For sustainable restoration and preservation of wetland ecosystems in the region, it is critical to develop water resources management strategies that limit groundwater extraction rate to that of recharge rate. PMID:22508123

  2. Measurement of impulse peak insertion loss for four hearing protection devices in field conditions

    PubMed Central

    Murphy, William J.; Flamme, Gregory A.; Meinke, Deanna K.; Sondergaard, Jacob; Finan, Donald S.; Lankford, James E.; Khan, Amir; Vernon, Julia; Stewart, Michael

    2015-01-01

    Objective In 2009, the U.S. Environmental Protection Agency (EPA) proposed an impulse noise reduction rating (NRR) for hearing protection devices based upon the impulse peak insertion loss (IPIL) methods in the ANSI S12.42-2010 standard. This study tests the ANSI S12.42 methods with a range of hearing protection devices measured in field conditions. Design The method utilizes an acoustic test fixture and three ranges for impulse levels: 130–134, 148–152, and 166–170 dB peak SPL. For this study, four different models of hearing protectors were tested: Bilsom 707 Impact II electronic earmuff, E·A·R Pod Express, E·A·R Combat Arms version 4, and the Etymotic Research, Inc. Electronic BlastPLG™ EB1. Study sample Five samples of each protector were fitted on the fixture or inserted in the fixture's ear canal five times for each impulse level. Impulses were generated by a 0.223 caliber rifle. Results The average IPILs increased with peak pressure and ranged between 20 and 38 dB. For some protectors, significant differences were observed across protector examples of the same model, and across insertions. Conclusions The EPA's proposed methods provide consistent and reproducible results. The proposed impulse NRR rating should utilize the minimum and maximum protection percentiles as determined by the ANSI S12.42-2010 methods. PMID:22176308

  3. Measurement profiles of nano-scale ion beam for optimized radiation energy losses

    NASA Astrophysics Data System (ADS)

    Woo, T. H.; Cho, H. S.

    2011-10-01

    The behavior of charged particles is investigated for nano-scale ion beam therapy using a medical accelerator. Computational work is performed for the Bragg-peak simulation, which is focused on human organ material of pancreas and thyroid. The Results show that the trends of the dose have several different kinds of distributions. Before constructing a heavy ion collider, this study can give us the reliability of the therapeutic effect. Realistic treatment using human organs is calculated in a simple and cost effective manner using the computational code, the Stopping and Range of Ions in Matter 2008 (SRIM 2008). Considering the safety of the therapy, it is suggested to give a patient orient planning of the cancer therapy. The energy losses in ionization and phonon are analyzed, which are the behaviors in the molecular level nano-scopic investigation. The different fluctuations are shown at 150 MeV, where the lowest temperature is found in proton and pancreas case. Finally, the protocol for the radiation therapy is constructed by the simulation in which the procedure for a better therapy is selected. An experimental measurement incorporated with the simulations could be programmed by this protocol.

  4. Studies of 3He polarization losses during NMR and EPR measurment and Polarized 3He target cell lifetime

    NASA Astrophysics Data System (ADS)

    An, Peibo

    2014-09-01

    The 3He target cell polarized by spin-exchange optical pumping(SEOP) is used as a neutron substitute to study the inner structure of the neutron. In our lab, nuclear-magnetic-resonance(NMR) is used to measure the relative polarization and electron-paramagnetic-resonance(EPR) is used to measure the spin exchange EPR frequency shift parameter of potassium and rubidium in our target cell presented in magnetic fields. The alkali in the cell is used to facilitate the polarization of 3He. The first part of my work presents the study of the polarization losses of the cell during both NMR and EPR. With the help of improved RF coils, we keep the background noise received by pickup coils reasonably low, but three other kinds of losses are inevitable: losses during Adiabatic Fast Passage (AFP) sweep, losses due to flux change caused by different cell orientation with respect to RF fields and physical losses. Fortunately there is only flux change in NMR measurements. The second part of my work presents the study of cell lifetime improvement. The polarization decreases in a process called relaxation exponentially. The lifetime of a cell is how long it can keep its polarization. The typical lifetime of cells produced in our lab is about 22 hours. With a newly designed vacuum system. The 3He target cell polarized by spin-exchange optical pumping(SEOP) is used as a neutron substitute to study the inner structure of the neutron. In our lab, nuclear-magnetic-resonance(NMR) is used to measure the relative polarization and electron-paramagnetic-resonance(EPR) is used to measure the spin exchange EPR frequency shift parameter of potassium and rubidium in our target cell presented in magnetic fields. The alkali in the cell is used to facilitate the polarization of 3He. The first part of my work presents the study of the polarization losses of the cell during both NMR and EPR. With the help of improved RF coils, we keep the background noise received by pickup coils reasonably low, but

  5. An X-band waveguide measurement technique for the accurate characterization of materials with low dielectric loss permittivity.

    PubMed

    Allen, Kenneth W; Scott, Mark M; Reid, David R; Bean, Jeffrey A; Ellis, Jeremy D; Morris, Andrew P; Marsh, Jeramy M

    2016-05-01

    In this work, we present a new X-band waveguide (WR90) measurement method that permits the broadband characterization of the complex permittivity for low dielectric loss tangent material specimens with improved accuracy. An electrically long polypropylene specimen that partially fills the cross-section is inserted into the waveguide and the transmitted scattering parameter (S21) is measured. The extraction method relies on computational electromagnetic simulations, coupled with a genetic algorithm, to match the experimental S21 measurement. The sensitivity of the technique to sample length was explored by simulating specimen lengths from 2.54 to 15.24 cm, in 2.54 cm increments. Analysis of our simulated data predicts the technique will have the sensitivity to measure loss tangent values on the order of 10(-3) for materials such as polymers with relatively low real permittivity values. The ability to accurately characterize low-loss dielectric material specimens of polypropylene is demonstrated experimentally. The method was validated by excellent agreement with a free-space focused-beam system measurement of a polypropylene sheet. This technique provides the material measurement community with the ability to accurately extract material properties of low-loss material specimen over the entire X-band range. This technique could easily be extended to other frequency bands. PMID:27250447

  6. An X-band waveguide measurement technique for the accurate characterization of materials with low dielectric loss permittivity

    NASA Astrophysics Data System (ADS)

    Allen, Kenneth W.; Scott, Mark M.; Reid, David R.; Bean, Jeffrey A.; Ellis, Jeremy D.; Morris, Andrew P.; Marsh, Jeramy M.

    2016-05-01

    In this work, we present a new X-band waveguide (WR90) measurement method that permits the broadband characterization of the complex permittivity for low dielectric loss tangent material specimens with improved accuracy. An electrically long polypropylene specimen that partially fills the cross-section is inserted into the waveguide and the transmitted scattering parameter (S21) is measured. The extraction method relies on computational electromagnetic simulations, coupled with a genetic algorithm, to match the experimental S21 measurement. The sensitivity of the technique to sample length was explored by simulating specimen lengths from 2.54 to 15.24 cm, in 2.54 cm increments. Analysis of our simulated data predicts the technique will have the sensitivity to measure loss tangent values on the order of 10-3 for materials such as polymers with relatively low real permittivity values. The ability to accurately characterize low-loss dielectric material specimens of polypropylene is demonstrated experimentally. The method was validated by excellent agreement with a free-space focused-beam system measurement of a polypropylene sheet. This technique provides the material measurement community with the ability to accurately extract material properties of low-loss material specimen over the entire X-band range. This technique could easily be extended to other frequency bands.

  7. Asphaltene content and composition as a measure of Deepwater Horizon oil spill losses within the first 80 days

    USGS Publications Warehouse

    Lewan, M.D.; Warden, A.; Dias, R.F.; Lowry, Z.K.; Hannah, T.L.; Lillis, P.G.; Kokaly, R.F.; Hoefen, T.M.; Swayze, G.A.; Mills, C.T.; Harris, S.H.; Plumlee, G.S.

    2014-01-01

    The composition and content of asphaltenes in spilled and original wellhead oils from the Deepwater Horizon (DWH) incident provide information on the amount of original oil lost and the processes most responsible for the losses within the first 80 days of the active spill. Spilled oils were collected from open waters, coastal waters and coastal sediments during the incident. Asphaltenes are the most refractory component of crude oils but their alteration in the spilled oils during weathering prevents them from being used directly as a conservative component to calculate original oil losses. The alteration is reflected by their increase in oxygen content and depletion in 12C. Reconnaissance experiments involving evaporation, photo-oxidation, microbial degradation, dissolution, dispersion and burning indicate that the combined effects of photo-oxidation and evaporation are responsible for these compositional changes. Based on measured losses and altered asphaltenes from these experiments, a mean of 61 ± 3 vol% of the original oil was lost from the surface spilled oils during the incident. This mean percentage of original oil loss is considerably larger than previous estimates of evaporative losses based on only gas chromatography (GC) amenable hydrocarbons (32–50 vol%), and highlights the importance of using asphaltenes, as well as GC amenable parameters in evaluating original oil losses and the processes responsible for the losses.

  8. Redox Bias in Loss on Ignition Moisture Measurement for Relatively Pure Plutonium-Bearing Oxide Materials

    SciTech Connect

    Eller, P. G.; Stakebake, J. L.; Cooper, T. D.

    2002-02-26

    This paper evaluates potential analytical bias in application of the Loss on Ignition (LOI) technique for moisture measurement to relatively pure (plutonium assay of 80 wt.% or higher) oxides containing uranium that have been stabilized according to stabilization and storage standard DOE-STD-3013-2000 (STD- 3013). An immediate application is to Rocky Flats (RF) materials derived from high-grade metal hydriding separations subsequently treated by multiple calcination cycles. Specifically evaluated are weight changes due to oxidation/reduction of multivalent impurity oxides that could mask true moisture equivalent content measurement. Process knowledge and characterization of materials representing complex-wide materials to be stabilized and packaged according to STD-3013, and particularly for the immediate RF target stream, indicate that oxides of uranium, iron and gallium are the only potential multivalent constituents expected to be present above 0.5 wt.%. The evaluation show s that of these constituents, with few exceptions, only uranium oxides can be present at a sufficient level to produce weight gain biases significant with respect to the LOI stability test. In general, these formerly high-value, high-actinide content materials are reliably identifiable by process knowledge and measurement. Significant bias also requires that UO2 components remain largely unoxidized after calcination and are largely converted to U3O8 during LOI testing at only slightly higher temperatures. Based on well-established literature, it is judged unlikely that this set of conditions will be realized in practice. We conclude that it is very likely that LOI weight gain bias will be small for the immediate target RF oxide materials containing greater than 80 wt.% plutonium plus a much smaller uranium content. Recommended tests are in progress to confirm these expectations and to provide a more authoritative basis for bounding LOI oxidation/reduction biases. LOI bias evaluation is more

  9. Redox bias in loss of ignition moisture measurement for relatively pure plutonium-bearing oxide materials.

    SciTech Connect

    Eller, P. G.; Stakebake, J. L.; Cooper, T. D.

    2001-01-01

    This paper evaluates potential analytical bias in application of the Loss on Ignition (LOI) technique for moisture measurement to relatively pure (plutonium assay of 80 wt.% or higher) oxides containing uranium that have been stabilized according to stabilization and storage standard DOE-STD-3013-2000 (STD-3013). An immediate application is to Rocky Flats (RF) materials derived from highgrade metal hydriding separations subsequently treated by multiple calcination cycles. Specifically evaluated are weight changes due to oxidatiodreduction of multivalent impurity oxides that could mask true moisture equivalent content measurement. Process knowledge and characterization of materials representing complex-wide materials to be stabilized and packaged according to STD-3013, and particularly for the immediate RF target stream, indicate that oxides of uranium, iron and gallium are the only potential multivalent constituents expected to be present above 0.5 wt.%. The evaluation shows that of these constituents, with few exceptions, only uranium oxides can be present at a sufficient level to produce weight gain biases significant with respect to the LO1 stability test. In general, these formerly high-value, high-actinide content materials are reliably identifiable by process knowledge and measurement. Si&icant bias also requires that UO1 components remain largely unoxidized after calcination and are largely converted to U30s clsning LO1 testing at only slightly higher temperatures. Based on wellestablished literature, it is judged unlikely that this set of conditions will be realized in practice. We conclude that it is very likely that LO1 weight gain bias will be small for the immediate target RF oxide materials containing greater than 80 wt.% plutonium plus a much smaller uranium content. Recommended tests are in progress to confum these expectations and to provide a more authoritative basis for bounding LO1 oxidatiodreduction biases. LO1 bias evaluation is more difficult

  10. Test bench HEATREC for heat loss measurement on solar receiver tubes

    NASA Astrophysics Data System (ADS)

    Márquez, José M.; López-Martín, Rafael; Valenzuela, Loreto; Zarza, Eduardo

    2016-05-01

    In Solar Thermal Electricity (STE) plants the thermal energy of solar radiation is absorbed by solar receiver tubes (HCEs) and it is transferred to a heat transfer fluid. Therefore, heat losses of receiver tubes have a direct influence on STE plants efficiency. A new test bench called HEATREC has been developed by Plataforma Solar de Almería (PSA) in order to determinate the heat losses of receiver tubes under laboratory conditions. The innovation of this test bench consists in the possibility to determine heat losses under controlled vacuum.

  11. Mitigation Measures Following a Loss-of-Residual-Heat-Removal Event During Shutdown

    SciTech Connect

    Seul, Kwang Won; Bang, Young Seok; Kim, Hho Jung

    2000-10-15

    The transient following a loss-of-residual-heat-removal event during shutdown was analyzed to determine the containment closure time (CCT) to prevent uncontrolled release of fission products and the gravity-injection path and rate (GIPR) for effective core cooling using the RELAP5/MOD3.2 code. The plant conditions of Yonggwang Units 3 and 4, a pressurized water reactor (PWR) of 2815-MW(thermal) power in Korea, were reviewed, and possible event sequences were identified. From the CCT analysis for the five cases of typical plant configurations, it was estimated for the earliest CCT to be 40 min after the event in a case with a large cold-leg opening and emptied steam generators (SGs). However, the case with water-filled SGs significantly delayed the CCT through the heat removal to the secondary side. From the GIPR analysis for the six possible gravity-injection paths from the refueling water storage tank (RWST), the case with the injection point and opening on the other leg side was estimated to be the most suitable path to avoid core boiling. In addition, from the sensitivity study, it was evaluated for the plant to be capable of providing the core cooling for the long-term transient if nominal RWST water is available. As a result, these analysis methods and results will provide useful information in understanding the plant behavior and preparing the mitigation measures after the event, especially for Combustion Engineering-type PWR plants. However, to directly apply the analysis results to the emergency procedure for such an event, additional case studies are needed for a wide range of operating conditions such as reactor coolant inventory, RWST water temperature, and core decay heat rate.

  12. Daily energy expenditure and physical activity measured in Parkinson's disease patients with and without weight loss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Patients with Parkinson's disease (PD) commonly exhibit weight loss, which investigators attribute to various factors, including elevated resting energy expenditure. We tested the hypothesis that daily energy expenditure (DEE) and its components, resting energy expenditure (REF) and physical activit...

  13. Theoretical Basis and Application for Measuring Pork Loin Drip Loss Using Microwave Spectroscopy

    PubMed Central

    Mason, Alex; Abdullah, Badr; Muradov, Magomed; Korostynska, Olga; Al-Shamma’a, Ahmed; Bjarnadottir, Stefania Gudrun; Lunde, Kathrine; Alvseike, Ole

    2016-01-01

    During cutting and processing of meat, the loss of water is critical in determining both product quality and value. From the point of slaughter until packaging, water is lost due to the hanging, movement, handling, and cutting of the carcass, with every 1% of lost water having the potential to cost a large meat processing plant somewhere in the region of €50,000 per day. Currently the options for monitoring the loss of water from meat, or determining its drip loss, are limited to destructive tests which take 24–72 h to complete. This paper presents results from work which has led to the development of a novel microwave cavity sensor capable of providing an indication of drip loss within 6 min, while demonstrating good correlation with the well-known EZ-Driploss method (R2 = 0.896). PMID:26848661

  14. Theoretical Basis and Application for Measuring Pork Loin Drip Loss Using Microwave Spectroscopy.

    PubMed

    Mason, Alex; Abdullah, Badr; Muradov, Magomed; Korostynska, Olga; Al-Shamma'a, Ahmed; Bjarnadottir, Stefania Gudrun; Lunde, Kathrine; Alvseike, Ole

    2016-01-01

    During cutting and processing of meat, the loss of water is critical in determining both product quality and value. From the point of slaughter until packaging, water is lost due to the hanging, movement, handling, and cutting of the carcass, with every 1% of lost water having the potential to cost a large meat processing plant somewhere in the region of €50,000 per day. Currently the options for monitoring the loss of water from meat, or determining its drip loss, are limited to destructive tests which take 24-72 h to complete. This paper presents results from work which has led to the development of a novel microwave cavity sensor capable of providing an indication of drip loss within 6 min, while demonstrating good correlation with the well-known EZ-Driploss method (R² = 0.896). PMID:26848661

  15. Peculiarities in electromagnetic behavior of MF NbTi composites for AC use

    SciTech Connect

    Hlasnik, I.; Fukui, S.; Amemiya, N.

    1994-07-01

    The paper presents results obtained in the study of the current-voltage characteristics, critical and quenching currents as well as of the AC transport current and magnetization losses in four series of fine filament NbTi composites prepared by Showa Electric Wire and Cable Co., Japan. Complementary measurements have been made also on a commercially available type T AC superconducting wire produced by GEC Alsthom Company, France. The samples differ in filament diameter, matrix thickness between filaments and in the number and structure of filament bundles in the composite. In two series of samples barrier type artificial pinning centers have been introduced to increase J{sub c} and decrease the normalized magnetization losses. The conclusions concerning the optimization of multifilamentary composites and cables for AC use at low working magnetic field are briefly reviewed.

  16. Sound Pressure Levels Measured in a University Concert Band: A Risk of Noise-Induced Hearing Loss?

    ERIC Educational Resources Information Center

    Holland, Nicholas V., III

    2008-01-01

    Researchers have reported public school band directors as experiencing noise-induced hearing loss. Little research has focused on collegiate band directors and university student musicians. The present study measures the sound pressure levels generated within a university concert band and compares sound levels with the criteria set by the…

  17. Antenna and radome loss measurements for MFMR and PMIS with appendix on MFMR/PMIS computer programs

    NASA Technical Reports Server (NTRS)

    Carver, K. R.; Cooper, W. K.

    1975-01-01

    The NMSU/PSL radiometer antenna calibration facility is described, and the antenna and radome loss measurements made on the passive microwave imaging system and the multifrequency microwave radiometer are summarized. Antenna/radome data reduction techniques, estimation of sky brightness temperatures, and bucket performance tests are presented along with radiometer computer programs.

  18. Measuring Li+ inventory losses in LiCoO2/graphite cells using Raman microscopy

    DOE PAGESBeta

    Snyder, Chelsea Marie; Apblett, Christopher A.; Grillet, Anne; Thomas Edwin Beechem; Duquette, David

    2016-03-25

    Here, the contribution from loss of Li+ inventory to capacity fade is described for slow rates (C/10) and long-term cycling (up to 80 cycles). It was found through electrochemical testing and ex-situ Raman analysis that at these slow rates, the entirety of capacity loss up to 80 cycles can be explained by loss of Li+ inventory in the cell. The Raman spectrum of LiCoO2 is sensitive to the state of lithiation and can therefore be leveraged to quantify the state of lithiation for individual particles. With these Raman derived estimates, the lithiation state of the cathode in the discharged statemore » is compared to electrochemical data as a function of cycle number. High correlation is found between Raman quantifications of cycleable lithium and the capacity fade. Additionally, the linear relationship between discharge capacity and cell overpotential suggests that the loss of capacity stems from an impedance rise of the electrodes, which based on Li inventory losses, is caused by SEI formation and repair.« less

  19. Measuring and modelling interception loss by an isolated olive tree in a traditional olive grove - pasture system

    NASA Astrophysics Data System (ADS)

    Nóbrega, Cristina; Pereira, Fernando L.; Valente, Fernanda

    2015-04-01

    Water losses associated to the rainfall interception process by trees can be an important component of the local hydrologic balance and must be accounted for when implementing any sustainable water management programme. In many dry areas of the Mediterranean region where agro-forestry systems are common, those programmes are crucial to foster adequate water conservation measures. Recent studies have shown that the evaluation of interception loss in sparse forests or tree plantations should be made for individual trees, being the total value determined as the sum of the individual contributions. Following this approach, rainfall interception was measured and modelled over two years, in an isolated Olea europeaea L. tree, in a traditional low-density olive grove in Castelo Branco, central Portugal. Total interception loss over the experimental period was 243.5 mm, on a tree crown projected area basis, corresponding to 18.0% of gross rainfall (Pg). Modelling made for each rainfall event using the sparse version of the Gash model, slightly underestimated interception loss with a value of 240.5 mm, i.e., 17.8 % ofPg. Modelling quality, evaluated according to a number of criteria, was good, allowing the conclusion that the methodology used was adequate. Modelling was also made on a daily basis, i.e., assuming a single storm per rainday. In this case, interception loss was overestimated by 12%, mostly because 72% of all rainfall events lasted for more than a day.

  20. In situ detection method for obtaining permeability of Fe-based amorphous alloys: ac resistance measurement for Fe{sub 84}Nb{sub 7}B{sub 9}

    SciTech Connect

    Ichitsubo, Tetsu; Matsubara, Eiichiro; Tanaka, Satoshi; Nishiyama, Nobuyuki; Amiya, Kenji

    2005-01-17

    In this letter, we propose an in situ detection method for obtaining permeability of soft magnetic Fe-based amorphous alloys. The temperature dependence of ac resistance was measured at different frequencies during heat treatment of Fe{sub 84}Nb{sub 7}B{sub 9} amorphous alloys. A significant increase in the ac ({approx}1000 kHz) resistance appears at around 920 K during the heating process, which arises from the skin effect caused by a marked increase in sample permeability. This skin effect diminishes when the sample is heated to approximately 1100 K, which corresponds to the decrease in its permeability. Consequently, we note that the ac resistance measurement is useful for quick in situ assessment to achieve the soft magnetic property of an Fe-based amorphous alloy.

  1. Visual Attention Measures Predict Pedestrian Detection in Central Field Loss: A Pilot Study

    PubMed Central

    Alberti, Concetta F.; Horowitz, Todd; Bronstad, P. Matthew; Bowers, Alex R.

    2014-01-01

    Purpose The ability of visually impaired people to deploy attention effectively to maximize use of their residual vision in dynamic situations is fundamental to safe mobility. We conducted a pilot study to evaluate whether tests of dynamic attention (multiple object tracking; MOT) and static attention (Useful Field of View; UFOV) were predictive of the ability of people with central field loss (CFL) to detect pedestrian hazards in simulated driving. Methods 11 people with bilateral CFL (visual acuity 20/30-20/200) and 11 age-similar normally-sighted drivers participated. Dynamic and static attention were evaluated with brief, computer-based MOT and UFOV tasks, respectively. Dependent variables were the log speed threshold for 60% correct identification of targets (MOT) and the increase in the presentation duration for 75% correct identification of a central target when a concurrent peripheral task was added (UFOV divided and selective attention subtests). Participants drove in a simulator and pressed the horn whenever they detected pedestrians that walked or ran toward the road. The dependent variable was the proportion of timely reactions (could have stopped in time to avoid a collision). Results UFOV and MOT performance of CFL participants was poorer than that of controls, and the proportion of timely reactions was also lower (worse) (84% and 97%, respectively; p = 0.001). For CFL participants, higher proportions of timely reactions correlated significantly with higher (better) MOT speed thresholds (r = 0.73, p = 0.01), with better performance on the UFOV divided and selective attention subtests (r = −0.66 and −0.62, respectively, p<0.04), with better contrast sensitivity scores (r = 0.54, p = 0.08) and smaller scotomas (r = −0.60, p = 0.05). Conclusions Our results suggest that brief laboratory-based tests of visual attention may provide useful measures of functional visual ability of individuals with CFL relevant to more

  2. Calcium measurements with electron probe X-ray and electron energy loss analysis.

    PubMed Central

    LeFurgey, A; Ingram, P

    1990-01-01

    This paper presents a broad survey of the rationale for electron probe X-ray microanalysis (EPXMA) and the various methods for obtaining qualitative and quantitative information on the distribution and amount of elements, particularly calcium, in cryopreserved cells and tissues. Essential in an introductory consideration of microanalysis in biological cryosections is the physical basis for the instrumentation, fundamentals of X-ray spectrometry, and various analytical modes such as static probing and X-ray imaging. Some common artifacts are beam damage and contamination. Inherent pitfalls of energy dispersive X-ray systems include Si escape peaks, doublets, background, and detector calibration shifts. Quantitative calcium analysis of thin cryosections is carried out in real time using a multiple least squares fitting program on filtered X-ray spectra and normalizing the calcium peak to a portion of the continuum. Recent work includes the development of an X-ray imaging system where quantitative data can be retrieved off-line. The minimum detectable concentration of calcium in biological cryosections is approximately 300 mumole kg dry weight with a spatial resolution of approximately 100 A. The application of electron energy loss (EELS) techniques to the detection of calcium offers the potential for greater sensitivity and spatial resolution in measurement and imaging. Determination of mass thickness with EELS can facilitate accurate calculation of wet weight concentrations from frozen hydrated and freeze-dried specimens. Calcium has multiple effects on cell metabolism, membrane transport and permeability and, thus, on overall cell physiology or pathophysiology. Cells can be rapidly frozen for EPXMA during basal or altered functional conditions to delineate the location and amount of calcium within cells and the changes in location and concentration of cations or anions accompanying calcium redistribution. Recent experiments in our laboratory document that EPXMA in

  3. Thermal Evaporation Loss Measurements on Quasicrystal (Ti-Zr-Ni) and Glass Forming (Vit 106 and Vit 106a) Liquids

    NASA Astrophysics Data System (ADS)

    Blodgett, M. E.; Gangopadhyay, A. K.; Kelton, K. F.

    2015-04-01

    Thermal evaporation loss measurements made using the electrostatic levitation (ESL) technique for one binary Ti-Zr, two ternary Ti-Zr-Ni, and two glass-forming (Vit 106 and Vit 106a) alloy liquids are reported. The containerless environment enables measurements not only for the equilibrium liquids but also for the metastable supercooled liquids. The data follow the Langmuir equation when the activity coefficient of the solute atoms, a measure for the deviation from the ideal solution behavior, is taken into account. An estimate for the activity coefficient of Ni in the Ti-Zr liquid is made from these data, demonstrating the effectiveness of ESL for such measurements.

  4. Assessment of crop yield losses in Punjab and Haryana using two years of continuous in-situ ozone measurements

    NASA Astrophysics Data System (ADS)

    Sinha, B.; Singh Sangwan, K.; Maurya, Y.; Kumar, V.; Sarkar, C.; Chandra, B. P.; Sinha, V.

    2015-01-01

    In this study we use a high quality dataset of in-situ ozone measurements at a suburban site called Mohali in the state of Punjab to estimate ozone related crop yield losses for wheat, rice, cotton and maize for Punjab and the neighbouring state Haryana for the years 2011-2013. We inter-compare crop yield loss estimates according to different exposure metrics such as AOT40 and M7 for the two major crop growing seasons of Kharif (June-October) and Rabi (November-April) and establish a new crop yield exposure relationship for South Asian wheat and rice cultivars. These are a factor of two more sensitive to ozone induced crop yield losses compared to their European and American counterparts. Relative yield losses based on the AOT40 metrics ranged from 27-41% for wheat, 21-26% for rice, 9-11% for maize and 47-58% for cotton. Crop production losses for wheat amounted to 20.8 million t in fiscal year 2012-2013 and 10.3 million t in fiscal year 2013-2014 for Punjab and Haryana jointly. Crop production losses for rice totalled 5.4 million t in fiscal year 2012-2013 and 3.2 million t year 2013-2014 for Punjab and Haryana jointly. The Indian National Food Security Ordinance entitles ~ 820 million of India's poor to purchase about 60 kg of rice/wheat per person annually at subsidized rates. The scheme requires 27.6 Mt of wheat and 33.6 Mt of rice per year. Mitigation of ozone related crop production losses in Punjab and Haryana alone could provide >50% of the wheat and ~10% of the rice required for the scheme. The total economic cost losses in Punjab and Haryana amounted to USD 6.5 billion in the fiscal year 2012-2013 and USD 3.7 billion in the fiscal year 2013-2014. This economic loss estimate represents a very conservative lower limit based on the minimum support price of the crop, which is lower than the actual production costs. The upper limit for ozone related crop yield losses in entire India currently amounts to 3.5-20% of India's GDP. Mitigation of high surface ozone

  5. Repeated Measures in Case Studies Relating Social Competence and Weight Loss in Two Obese Adolescents

    ERIC Educational Resources Information Center

    Meyer, Sonia Beatriz; Barbosa, Debora Regina

    2007-01-01

    In individual behavior therapy two clients were evaluated using behavior categories created by the therapist. Both clients were observed to improve in terms of social competence. One demonstrated a significant inverse correlation between improvement of social competence and weight loss during treatment (16 sessions) and lost weight. The other…

  6. Repeated Measures in Case Studies Relating Social Competence and Weight Loss in Two Obese Adolescents

    ERIC Educational Resources Information Center

    Meyer, Sonia Beatriz; Barbosa, Debora Regina

    2009-01-01

    In individual behavior therapy two clients were evaluated using behavior categories created by the therapist. Both clients were observed to improve in terms of social competence. One demonstrated a significant inverse correlation between improvement of social competence and weight loss during treatment (16 sessions) and lost weight. The other…

  7. Measuring Meaning: Searching for and Making Sense of Spousal Loss in Late-Life

    ERIC Educational Resources Information Center

    Coleman, Rachel A.; Neimeyer, Robert A.

    2010-01-01

    Despite much recent theorizing, evidence regarding the temporal relationship of sense-making to adjustment following bereavement remains relatively sparse. This study examined the role of searching for and making sense of loss in late-life spousal bereavement, using prospective, longitudinal data from the Changing Lives of Older Couples (CLOC)…

  8. Fitness Instructors: How Does Their Knowledge on Weight Loss Measure Up?

    ERIC Educational Resources Information Center

    Forsyth, Glenys; Handcock, Phil; Rose, Elaine; Jenkins, Carolyn

    2005-01-01

    Objective: To examine the knowledge, approaches and attitudes of fitness instructors dealing with clients seeking weight loss advice. Design: A qualitative project whereby semi-structured interviews were conducted with ten fitness instructors representing a range of qualifications, work settings and years of experience. Setting: Interviews were…

  9. Measurement of hearing loss due to perforated tympanic membrane using image processing techniques

    NASA Astrophysics Data System (ADS)

    Sardesai, Neha; Sardesai, Ravindra; Chang, Chein-I.

    2014-05-01

    The tympanic membrane (ear drum) is a thin tissue film that is stretched between the outer and middle ear. Sound waves travel from outside the ear, and strike the tympanic membrane resulting in its vibration. These vibrations amplify the sound waves and transmit them to the ossicles (auditory bones). The magnitude of amplification is directly proportional to vibrating area of tympanic membrane. Hence a perforation in this membrane would result in hearing loss. Pure-tone audiometry is the traditional procedure used to detect the amount of hearing loss in a patient. However, it is lengthy and less efficient, as it largely depends on the response of the patient to sound intensity and frequency of pure-tones. We present a relatively more efficient approach to determine hearing loss due to perforated tympanic membrane using image processing techniques. We describe an algorithm that uses unsharp masking to sharpen images of the perforations as well as the tympanic membrane. Then, it converts the image into a binary image using thresholding. A median filter is applied to get rid of the noise component in the image. The ratio of the area of perforation and total area of tympanic membrane will define the percentage of hearing loss. Our approach will eliminate the error introduced due to patient dependency as in the traditional method.

  10. Mining and biodiversity offsets: a transparent and science-based approach to measure "no-net-loss".

    PubMed

    Virah-Sawmy, Malika; Ebeling, Johannes; Taplin, Roslyn

    2014-10-01

    Mining and associated infrastructure developments can present themselves as economic opportunities that are difficult to forego for developing and industrialised countries alike. Almost inevitably, however, they lead to biodiversity loss. This trade-off can be greatest in economically poor but highly biodiverse regions. Biodiversity offsets have, therefore, increasingly been promoted as a mechanism to help achieve both the aims of development and biodiversity conservation. Accordingly, this mechanism is emerging as a key tool for multinational mining companies to demonstrate good environmental stewardship. Relying on offsets to achieve "no-net-loss" of biodiversity, however, requires certainty in their ecological integrity where they are used to sanction habitat destruction. Here, we discuss real-world practices in biodiversity offsetting by assessing how well some leading initiatives internationally integrate critical aspects of biodiversity attributes, net loss accounting and project management. With the aim of improving, rather than merely critiquing the approach, we analyse different aspects of biodiversity offsetting. Further, we analyse the potential pitfalls of developing counterfactual scenarios of biodiversity loss or gains in a project's absence. In this, we draw on insights from experience with carbon offsetting. This informs our discussion of realistic projections of project effectiveness and permanence of benefits to ensure no net losses, and the risk of displacing, rather than avoiding biodiversity losses ("leakage"). We show that the most prominent existing biodiversity offset initiatives employ broad and somewhat arbitrary parameters to measure habitat value and do not sufficiently consider real-world challenges in compensating losses in an effective and lasting manner. We propose a more transparent and science-based approach, supported with a new formula, to help design biodiversity offsets to realise their potential in enabling more responsible

  11. Food loss rates at the food retail, influencing factors and reasons as a basis for waste prevention measures.

    PubMed

    Lebersorger, S; Schneider, F

    2014-11-01

    This paper quantifies food loss rates for fruit & vegetables, dairy products and bread & pastry as well as donations to social services. In addition potential influencing factors and reasons for food losses are investigated in order to provide a basis for the development of waste prevention measures. Detailed data from 612 retail outlets all over Austria, which covered the period of one year, were analysed and sorting analyses of discarded food were carried out in a small sample of retail outlets. Food loss amounts to 1.3% of the sales of dairy products, 2.8% for bread & pastry and 4.2% for fruit & vegetables. Returned bread amounts to additional 9.7% of the sales of bread & pastry. The food loss rates are similar to the results of previous publications. At present, 7% of the food loss is donated to social services, 38% of retail outlets do not donate any articles at all. Food loss rates are declining with increasing sales areas, increasing numbers of purchases per year and increasing sales of the retail outlet, but explain only 33% or less of the variation of food loss rates. Large differences between retail outlets of comparable structure indicate potential for reduction. More than a quarter of discarded food articles did not show any flaws besides the expiration of the best before or sell-by date. Waste prevention approaches should focus on avoiding returns, transfer of best practices, information and education of employees and customers as well as strengthening the donation to social services. PMID:25060676

  12. Measurement of Self-Monitoring Web Technology Acceptance and Use in an e-Health Weight-Loss Trial

    PubMed Central

    Xiao, Lan; Blonstein, Andrea C.

    2013-01-01

    Abstract Background: Research on technology acceptance and use in e-health weight-loss interventions is limited. Using data from a randomized controlled trial of two e-health interventions, we evaluated the acceptance and use of a self-monitoring Web site for weight loss. Materials and Methods: We examined eight theoretical constructs about technology acceptance using adapted 5-point Likert scales and the association of measured Web site usage and weight loss. Results: All scales had high internal consistency (Cronbach's alpha=0.74–0.97) in both interventions and at 3 and 15 months (end of intensive and maintenance intervention, respectively). From 3 to 15 months mean scores changed unfavorably for two constructs (compatibility and behavioral intention) among coach-led intervention participants, who received ongoing feedback on their self-monitoring entries. Among self-directed intervention participants, who received minimal coach support, mean scores changed unfavorably for five constructs (usefulness, ease of use, concern, compatibility, and behavioral intention). At 3 months, usefulness, ease of use, effect, compatibility, and behavioral intention in the coach-led group (Pearson r=0.33–0.5) and usefulness and affect in the self-directed group (r=0.43–0.46) were significantly correlated with Web site usage, which was correlated with weight loss (β=−0.02, p≤0.001 for both interventions). From 3 to 15 months, mean score changes for usefulness and behavioral intention correlated significantly with Web site usage in the coach-led group. Conclusions: The adapted acceptance measures showed acceptable psychometric properties and significant associations with actual Web site use, which correlated with weight loss. Better understanding of technology acceptance and use in e-health weight-loss interventions may improve participant adherence and outcome. PMID:23952787

  13. Correlation of leachant analyses and weight loss measurements in the leaching of high-iron synthetic basalts

    SciTech Connect

    Tallman, R. L.

    1980-01-01

    Materials which simulate the slag product of the Slagging Pyrolysis Incinerator under consideration for the INEL Transuranic Waste Treatment Facility have been characterized. This slag is an iron-rich basalt-like material designed to contain the low-level TRU waste stored at INEL. Leach tests on synthetic compositions have been performed to provide information for process design and to indicate the quality of the waste form. Experiments have been performed to confirm that microbalance weight losses agree with the contents of the leachants as determined by chemical analyses. Deionized water was used as the leachant and the leachants from experiments at 70/sup 0/C were analyzed by atomic absorption and inductively-coupled plasma and flame emission techniques and by isotopic dilution mass spectrometry (for uranium). Leachant analyses provided both elemental leach rates ad weight loss leach rates. The weight loss leach rates were calculated from the sums of the analytically determined elemental contents of the leachants, converted to weights of oxides. These rates correlate with the elemental leach rates calculated from the microbalance weight loss, measured by a substitution-type electronic microbalance. Sample composition and devitrification effects, including microcracking effects, and comparisons of elemental leachant analyses and leach rates with microbalance weight losses are the most significant results of this work.

  14. Millimeter Wave Measurement of the Low-Loss Dielectric in Vacuum Electronic Devices with Reflection-Type Hemispherical Open Resonator

    NASA Astrophysics Data System (ADS)

    Shu, G. X.; Luo, Y.; Zhang, Q. S.; Su, J.; Wang, L.; Xu, Y.; Wang, S. F.

    2015-06-01

    Accurate dielectric properties are of great importance for the design and fabrication of the input and output windows in vacuum electronic devices. A reflection-type hemispherical open resonator (RTHOR) was designed through theoretical analysis and numerical simulation and also was utilized to measure the dielectric properties of the windows material sapphire. Compared with the two ports measurement, a simplified measurement system to obtain the dielectric performance was proposed and the RTHOR with only one coupling aperture was directly connected to a W-band vector network analyzer (VNA). The material properties can be easily calculated through the VNA measured port reflection coefficient (S11) resonant curve. Investigation shows that the permittivity and the loss tangent of the measured sapphire, which is used to construct the input and output window, is respectively about 9.40 and 1.80 × 10-4 at room temperature in W-band, which agree well with the reported results. Measured results also show that the simplified measurement system can provide a high accuracy for the measurement of low-loss dielectric in a relatively convenient way.

  15. Measuring Meaning: Searching For and Making Sense of Spousal Loss in Late-Life

    PubMed Central

    Coleman, Rachel A.; Neimeyer, Robert A.

    2010-01-01

    Despite much recent theorizing, evidence regarding the temporal relationship of sense-making to adjustment following bereavement remains relatively sparse. This study examined the role of searching for and making sense of loss in late-life spousal bereavement, using prospective, longitudinal data from the Changing Lives of Older Couples1 (CLOC) project (N=250). Searching at 6 and 18 months post-loss predicted both contemporaneous and subsequent grief. Sense-making was not related to grief for this sample. In contrast, sense-making at 6 months and 18 months predicted positive affect at 48 months, while searching had no prospective effect on this outcome. Searching at 6 months predicted depression at 18 months. Results are interpreted in terms of meaning-oriented theories of bereavement and processes promoting both adaptive and maladaptive outcomes. PMID:24482851

  16. Kramers-Kronig analysis of reflection electron-energy-loss spectra measured with a cylindrical mirror analyzer

    NASA Astrophysics Data System (ADS)

    Ohno, Youichi

    1989-04-01

    We have discussed a valence-electron energy-loss spectrum measured in reflection geometry using a cylindrical mirror analyzer (CMA) and derived the angular distribution of inelastic scattering, the momentum transfer, and the differential cross section per unit energy. If a critical inelastic-scattering angle is smaller than the angular aperture of the analyzer, the differential cross section no longer depends on momentum transfer. The reflection electron-energy-loss spectroscopy (REELS) spectra of MoS2 and graphite have been measured and the Kramers-Kronig analysis has been applied. The results are compared with those of the composite energy-loss function calculated from the energy-loss functions perpendicular and parallel to the c axis. It has been shown that the Kramers-Kronig analysis is still valid for the REELS spectra at higher incident energies than 500 eV and that the derived optical constants consist approximately of 80% of the perpendicular component and 20% of the parallel component.

  17. Development of ac Calorimetric Method for Thermal Diffusivity Measurement I. Contribution of Thermocouple Attachment in a Thin Sample

    NASA Astrophysics Data System (ADS)

    Hatta, Ichiro; Kato, Ryozo; Maesono, Akikazu

    1986-06-01

    In a very thin sample, the contribution of addenda, thermocouple, glue etc., to the precise measurement is considered especially in two typical cases, in which the thermocouple is attached to the sample surface using glue. In the one case, glue is painted over the whole one-sided region starting from the thermocouple on the surface and in the other, a small amount of glue is used to fix the thermocouple at a particular point on the surface. Consistent with the theoretical consideration, it is experimentally verified in both cases that the addenda do not affect determination of the thermal diffusivity.

  18. ACS Quicklook PDF products

    NASA Astrophysics Data System (ADS)

    Suchkov, Anatoly

    1999-12-01

    This report details the features of the ACS quicklook PDF products produced by the HST data pipeline. The requirements closely follow the design of paper products recommended by the Data Quality Committee, with appropriate changes required to fully support ACS.

  19. Measurement of loss angle, volume resistivity and surface resistivity of insulating materials used on solar cells

    NASA Technical Reports Server (NTRS)

    Doreswamy, C. V.

    1980-01-01

    The complete measuring and test system developed to measure the quality and the stability of insulating materials used on solar cell arrays for space application is described. The test set up and measurements are primarily aimed at the measurement and analysis of the degradation of the electrical insulating properties of material used on solar cells. Degradation characteristics of the material subject to thermal cycling, space plasma and very high electrical fields individually and in combination can be investigated.

  20. Measurements of Erosion Wear Volume Loss on Bare and Coated Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa; Sutter, James K.; Mondry, Richard J.; Bowman, Cheryl; Ma, Kong; Horan, Richard A.; Naik, Subhash K.; Cupp, Randall J.

    2003-01-01

    An investigation was conducted to examine the erosion behavior of uncoated and coated polymer matrix composite (PMC) specimens subjected to solid particle impingement using air jets. The PMCs were carbon-Kevlar (DuPont, Wilmington, DE) fiber-epoxy resin composites with a temperature capability up to 393 K (248 F). Tungsten carbide-cobalt (WC-Co) was the primary topcoat constituent. Bondcoats were applied to the PMC substrates to improve coating adhesion; then, erosion testing was performed at the University of Cincinnati. All erosion tests were conducted with Arizona road-dust (ARD), impinging at angles of 20 and 90 on both uncoated and two-layer coated PMCs at a velocity of 229 m/s and at a temperature of 366 K (200 F). ARD contains primarily 10-m aluminum oxide powders. Vertically scanning interference microscopy (noncontact, optical profilometry) was used to evaluate surface characteristics, such as erosion wear volume loss and depth, surface topography, and surface roughness. The results indicate that noncontact, optical interferometry can be used to make an accurate determination of the erosion wear volume loss of PMCs with multilayered structures while preserving the specimens. The two-layered (WC-Co topcoat and metal bondcoat) coatings on PMCs remarkably reduced the erosion volume loss by a factor of approximately 10. The tenfold increase in erosion resistance will contribute to longer PMC component lives, lower air friction, reduced related breakdowns, decreased maintenance costs, and increased PMC reliability. The decrease in the surface roughness of the coated vanes will lead to lower air friction and will subsequently reduce energy consumption. Eventually, the coatings could lead to overall economic savings.

  1. Calcium channel stability measured by gradual loss of excitability in pawn mutants of Paramecium aurelia.

    PubMed

    Schein, S J

    1976-12-01

    Mutants of Paramecium aurelia that are unable to reverse swimming direction are called pawns. They lack the inward ionic (calcium) current required for the upstroke of the electrically excitable membrane response. By following the progressive loss of reversal response and excitability in cells that are suddenly changed from a heterozygous (wild-type) state to a homozygous mutant state, an estimate of the stability and mean lifetime of the calcium channel has been obtained. During rapid growth, channel dilution due to division occurred, but no channel decay was observed. Under conditions of slow growth, decay could also be observed; channel lifetime was found to be from 5 to 8 days. PMID:1035256

  2. Measurements of Unexpected Ozone Loss in a Nighttime Space Shuttle Exhaust Plume: Implications for Geo-Engineering Projects

    NASA Astrophysics Data System (ADS)

    Avallone, L. M.; Kalnajs, L. E.; Toohey, D. W.; Ross, M. N.

    2008-12-01

    Measurements of ozone, carbon dioxide and particulate water were made in the nighttime exhaust plume of the Space Shuttle (STS-116) on 9 December 2006 as part of the PUMA/WAVE campaign (Plume Ultrafast Measurements Acquisition/WB-57F Ascent Video Experiment). The launch took place from Kennedy Space Center at 8:47 pm (local time) on a moonless night and the WB-57F aircraft penetrated the shuttle plume approximately 25 minutes after launch in the lowermost stratosphere. Ozone loss is not predicted to occur in a nighttime Space Shuttle plume since it has long been assumed that the main ozone loss mechanism associated with rocket emissions requires solar photolysis to drive several chlorine-based catalytic cycles. However, the nighttime in situ observations show an unexpected loss of ozone of approximately 250 ppb in the evolving exhaust plume, inconsistent with model predictions. We will present the observations of the shuttle exhaust plume composition and the results of photochemical models of the Space Shuttle plume. We will show that models constrained by known rocket emission kinetics, including afterburning, and reasonable plume dispersion rates, based on the CO2 observations, cannot explain the observed ozone loss. We will propose potential explanations for the lack of agreement between models and the observations, and will discuss the implications of these explanations for our understanding of the composition of rocket emissions. We will describe the potential consequences of the observed ozone loss for long-term damage to the stratospheric ozone layer should geo-engineering projects based on rocket launches be employed.

  3. Measured Mass-Loss Rates of Solar-like Stars as a Function of Age and Activity

    NASA Astrophysics Data System (ADS)

    Wood, Brian E.; Müller, Hans-Reinhard; Zank, Gary P.; Linsky, Jeffrey L.

    2002-07-01

    Collisions between the winds of solar-like stars and the local interstellar medium result in a population of hot hydrogen gas surrounding these stars. Absorption from this hot H I can be detected in high-resolution Lyα spectra of these stars from the Hubble Space Telescope. The amount of absorption can be used as a diagnostic for the stellar mass-loss rate. We present new mass-loss rate measurements derived in this fashion for four stars (ɛ Eri, 61 Cyg A, 36 Oph AB, and 40 Eri A). Combining these measurements with others, we study how mass loss varies with stellar activity. We find that for the solar-like GK dwarfs, the mass loss per unit surface area is correlated with X-ray surface flux. Fitting a power law to this relation yields M~F1.15+/-0.20X. The active M dwarf Proxima Cen and the very active RS CVn system λ And appear to be inconsistent with this relation. Since activity is known to decrease with age, the above power-law relation for solar-like stars suggests that mass loss decreases with time. We infer a power-law relation of M~t-2.00+/-0.52. This suggests that the solar wind may have been as much as 1000 times more massive in the distant past, which may have had important ramifications for the history of planetary atmospheres in our solar system, that of Mars in particular. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  4. [In-situ measurement on volatilization loss of ammonia in the vegetable field and its influencing factors].

    PubMed

    Gong, Wei-Wei; Zhang, Yi-Sheng; He, Ling-Yan; Luan, Sheng-Ji

    2011-02-01

    In order to obtain ammonia volatilization flux and volatilization loss rate in the vegetable field and investigate their relationship with environmental factors, an on-line monitoring system was used to measure the ammonia volatilization in the vegetable (Brassica rapa L. and lettuce) field after urea application during January to September, 2009. The system included a wind tunnel system, a gas collector and an online analyzer system with ion chromatography. The time resolution of measurement was 15 min. The recovery of the system was (92.6 +/- 3.4)%; the accumulated ammonia volatilization within 15 d continuous sampling after fertilization was regarded as the total loss. The accumulated ammonia volatilization of 12 d continuous sampling after fertilization accounted for (85.4 +/- 5.2)% of the total volatilization. The ammonia volatilization loss of broadcasting basal dressing and top dressing for Brassica rapa L. were 23.6% and 21.3%, respectively. The ammonia volatilization loss of holing basal dressing and top dressing for lettuce were 17.6% and 24.0%, respectively. The ammonia volatilization in the vegetable field mostly occurred in the first 2-3 weeks after fertilization. The ammonia volatilization flux had significant positive correlation with the nitrogen application rate, while the ammonia volatilization loss rate had negative correlation with the nitrogen application rate. The ammonia volatilization flux was positively correlated with the soil temperature (r = 0.041, p < 0.05) and the air temperature (r = 0.049, p < 0.01), while not significantly associated with the air humidity and the soil moisture. Temperature was found to be a main factor influencing the ammonia volatilization in the vegetable field. PMID:21528553

  5. Flood loss reduction of private households due to building precautionary measures -- lessons learned from the Elbe flood in August 2002

    NASA Astrophysics Data System (ADS)

    Kreibich, H.; Thieken, A. H.; Petrow, Th.; Müller, M.; Merz, B.

    2005-01-01

    Building houses in inundation areas is always a risk, since absolute flood protection is impossible. Where settlements already exist, flood damage must be kept as small as possible. Suitable means are precautionary measures such as elevated building configuration or flood adapted use. However, data about the effects of such measures are rare, and consequently, the efficiency of different precautionary measures is unclear. To improve the knowledge about efficient precautionary measures, approximately 1200 private households, which were affected by the 2002 flood at the river Elbe and its tributaries, were interviewed about the flood damage of their buildings and contents as well as about their precautionary measures. The affected households had little flood experience, i.e. only 15% had experienced a flood before. 59% of the households stated that they did not know, that they live in a flood prone area. Thus, people were not well prepared, e.g. just 11% had used and furnished their house in a flood adapted way and only 6% had a flood adapted building structure. Building precautionary measures are mainly effective in areas with frequent small floods. But also during the extreme flood event in 2002 building measures reduced the flood loss. From the six different building precautionary measures under study, flood adapted use and adapted interior fitting were the most effective ones. They reduced the damage ratio for buildings by 46% and 53%, respectively. The damage ratio for contents was reduced by 48% due to flood adapted use and by 53% due to flood adapted interior fitting. The 2002 flood motivated a relatively large number of people to implement private precautionary measures, but still much more could be done. Hence, to further reduce flood losses, people's motivation to invest in precaution should be improved. More information campaigns and financial incentives should be issued to encourage precautionary measures.

  6. Maladjustment of kidneys to microgravity: Design of measures to reduce the loss of calcium

    NASA Technical Reports Server (NTRS)

    Nechay, Bohdan R.

    1989-01-01

    Losses of skeletal calcium and body fluids occur during prolonged exposure to microgravity. The kidney plays a major role in regulating the physiological functions involved. Relative to this regulatory function, the kidney performs three operations: filtration of blood plasma through the glomeruli, reabsorption, and secretion of fluid and electrolytes so that needed components are retained and only waste is eliminated in the urine. Using data published in Biomedical Results from Skylab, researchers performed new calculations that reflect more directly the operations of the kidney in the handling of calcium, sodium, chloride, potassium and phosphate during space flight. These calculations revealed that the fraction of filtered calcium that was rejected by renal tubules and excreted in the urine increased by 71 percent, from 1.77 percent (preflight) to 3.02 percent (inflight) of the filtered load. This represents a large absolute increase because the total filtered amount is huge. Because the tubular rejection fraction of other ions increased relatively less than that of calcium, researchers postulate the inflight development of a specific renal defect that causes an excessive loss of calcium in urine and thereby contributes to the weakening of bones.

  7. O atoms loss coefficient on porous SiO2 and TiO2 measured by plasma induced fluorescence

    NASA Astrophysics Data System (ADS)

    Allegraud, Katia; Gatilova, Lina; Guaitella, Olivier; Guillon, Jean; Rousseau, Antoine

    2006-10-01

    The time evolution of O atoms density in the gas phase during the post-discharge of a pulsed plasma is studied using a plasma induced fluorescence technique (PIF): a main long pulse creates the plasma and a shorter one re-excites atoms in the time post-discharge was used. The gas pressure is 133 Pa in N2/O2 mixture and the plasma is a pulsed DC discharge. The surface loss coefficient of O atoms on pyrex, porous silica, porous TiO2 is measured, this latter being a photocatalytic material. It is shown that the presence of porous silica or TiO2 leads to a stong increase of the O atom surface loss coefficient. When nano cluster of TiO2 are deposited on porous silica, the loss coefficient is first high and comparable to the case of the porous silica, but decreases after few milliseconds. Such a decrease of the surface loss coefficient has recently been reported in a pulsed microwave discharge [1]. The effect of the pre-irradiation of the porous materials by external ultraviolet is also studied. [1] G. Cartry, X. Duten and A. Rousseau Plasma Sources Sci. Technol. 15 (2006) 479--488

  8. Novel procedure for estimating endogenous losses and measurement of apparent and true digestibility of phosphorus by growing pigs.

    PubMed

    Petersen, G I; Stein, H H

    2006-08-01

    An experiment was conducted to evaluate a novel procedure for estimating endogenous losses of P and for measuring the apparent total tract digestibility (ATTD) and true total tract digestibility (TTTD) of P in 5 inorganic P sources fed to growing pigs. The P sources were dicalcium phosphate (DCP), monocalcium phosphate (MCP) with 50% purity (MCP50), MCP with 70% purity (MCP70), MCP with 100% purity (MCP100), and monosodium phosphate (MSP). A gelatin-based, P-free basal diet was formulated and used to estimate endogenous losses of P. Five P-containing diets were formulated by adding 0.20% total P from each of the inorganic P sources to the basal diet. A seventh diet was formulated by adding 0.16% P from MCP70 to the basal diet. All diets were fed to 7 growing pigs in a 7 x 7 Latin square design, and urine and feces were collected during 5 d of each period. The endogenous loss of P was estimated as 139 +/- 18 mg/kg of DMI. The ATTD of P in MSP was greater (P < 0.05) than in DCP, MCP50, and MCP70 (91.9 vs. 81.5, 82.6, and 81.7%, respectively). In MSP, the TTTD of P was 98.2%. This value was greater (P < 0.05) than the TTTD of P in DCP, MCP50, and MCP70 (88.4, 89.5, and 88.6%, respectively). The ATTD and the TTTD for MCP70 were similar in diets formulated to contain 0.16 and 0.20% total P. Results from the current experiment demonstrate that a P-free diet may be used to measure endogenous losses of P in pigs. By adding inorganic P sources to this diet, the ATTD of P can be directly measured and the TTTD of P may be calculated for each source of P. PMID:16864873

  9. A Comparison Between Numerically Modelled and Experimentally Measured Loss Mechanisms in Wave Rotors

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    1993-01-01

    A numerical model has been developed which is capable of predicting the performance of a wave rotor (pressure exchanger) of specified geometry over a wide range of operating conditions. The model can account for the major loss mechanisms of leakage from the tube ends, fluid viscosity, heat transfer to the tube walls, finite tube opening time, shock waves, and non-uniform port flows. It is a one dimensional flow model which follows a single tube as it rotates past the various stationary ports. Since the model is relatively simple (i.e. one dimensional) it uses little computer time. This makes it suitable for design as well as analytical purposes. This paper will present a brief description of the model then discuss a comparison between the model predictions and several wave rotor experiments.

  10. Exploring a direct measurement of quark energy loss using semi-inclusive deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Peña, C.; Brooks, W.; Hakobyan, H.; Arratia, M.

    2012-02-01

    This work consists of an evaluation of the feasibility of a direct extraction of quark energy loss from the E02-104 experiment π+ data and using semi-inclusive Deep Inelastic Scattering (DIS). The method is based on a shape analysis of the pion energy spectrum, coupled with a GENIE simulation which includes an hadronic cascade model in nuclei. The pion energy spectrum from different nuclei such as C, Fe, and Pb is compared to that of deuterium in order to find a simple energy shift, which is predicted by BDMPS if the parton energy is high enough that the medium length L is smaller than a certain critical length Lc. GENIE is used to rule out hadronic interaction effects which could also explain the same behavior observed in data.

  11. The oblique incidence measurement of transmission loss by an impulse method

    NASA Astrophysics Data System (ADS)

    Davies, J. C.; Gibbs, B. M.

    1981-02-01

    The oblique incidence transmission loss of a free standing panel has been determined experimentally with the use of short duration impulsive signals. The geometry of the source, panel and receiver is such that the direct signal can be isolated and, on subsequent analysis, the infinite panel response obtained. Agreement with mass law is good and the angular and spectral variation of coincidence is clearly seen. Closer inspection of the time history of the transmitted waves shows a signal which arrives after the direct signal has effectively finished and before the arrival of scattered waves from the edge of the plate. Frequency analysis of this component reveals a coincidence type dip which is independent of angle and frequency.

  12. Fast pyrobolometers for measurements of plasma heat fluxes and radiation losses in the MST Reversed Field Pinch

    SciTech Connect

    Fiksel, G.; Frank, J.; Holly, D.

    1993-01-07

    Two types of fast bolometers are described for the plasma energy transport study in the Madison Symmetric Torus plasma confinement device. Both types use pyrocrystals of LiTaO[sub 3] or LiNbO[sub 3] as the sensors. One type is used for measurements of the radiated heat losses and is situated at the vacuum shell inner surface. Another type is insertable in the plasma and measures the plasma particle heat flux. The frequency response of the bolometers is measured to be in the 150--200 kHz range. The range of the measured power fluxes is 0.1 W/cm[sup 2] 10 kW/cm[sup 2] and can be adjusted by changing the size of the entrance aperture. The lower limit is determined by the amplifier noise and the frequency bandwidth, the higher limit by destruction of the bolometer sensor.

  13. Fast pyrobolometers for measurements of plasma heat fluxes and radiation losses in the MST Reversed Field Pinch

    SciTech Connect

    Fiksel, G.; Frank, J.; Holly, D.

    1993-01-07

    Two types of fast bolometers are described for the plasma energy transport study in the Madison Symmetric Torus plasma confinement device. Both types use pyrocrystals of LiTaO{sub 3} or LiNbO{sub 3} as the sensors. One type is used for measurements of the radiated heat losses and is situated at the vacuum shell inner surface. Another type is insertable in the plasma and measures the plasma particle heat flux. The frequency response of the bolometers is measured to be in the 150--200 kHz range. The range of the measured power fluxes is 0.1 W/cm{sup 2} 10 kW/cm{sup 2} and can be adjusted by changing the size of the entrance aperture. The lower limit is determined by the amplifier noise and the frequency bandwidth, the higher limit by destruction of the bolometer sensor.

  14. Assessment of crop yield losses in Punjab and Haryana using 2 years of continuous in situ ozone measurements

    NASA Astrophysics Data System (ADS)

    Sinha, B.; Singh Sangwan, K.; Maurya, Y.; Kumar, V.; Sarkar, C.; Chandra, B. P.; Sinha, V.

    2015-08-01

    In this study we use a high-quality data set of in situ ozone measurements at a suburban site called Mohali in the state of Punjab to estimate ozone-related crop yield losses for wheat, rice, cotton and maize for Punjab and the neighbouring state Haryana for the years 2011-2013. We intercompare crop yield loss estimates according to different exposure metrics, such as AOT40 (accumulated ozone exposure over a threshold of 40) and M7 (mean 7-hour ozone mixing ratio from 09:00 to 15:59), for the two major crop growing seasons of kharif (June-October) and rabi (November-April) and establish a new crop-yield-exposure relationship for southern Asian wheat, maize and rice cultivars. These are a factor of 2 more sensitive to ozone-induced crop yield losses compared to their European and American counterparts. Relative yield losses based on the AOT40 metrics ranged from 27 to 41 % for wheat, 21 to 26 % for rice, 3 to 5 % for maize and 47 to 58 % for cotton. Crop production losses for wheat amounted to 20.8 ± 10.4 million t in the fiscal year of 2012-2013 and 10.3 ± 4.7 million t in the fiscal year of 2013-2014 for Punjab and Haryana taken together. Crop production losses for rice totalled 5.4 ± 1.2 million t in the fiscal year of 2012-2013 and 3.2 ± 0.8 million t in the year 2013-2014 for Punjab and Haryana taken together. The Indian National Food Security Ordinance entitles ~ 820 million of India's poor to purchase about 60 kg of rice or wheat per person annually at subsidized rates. The scheme requires 27.6 Mt of wheat and 33.6 Mt of rice per year. The mitigation of ozone-related crop production losses in Punjab and Haryana alone could provide > 50 % of the wheat and ~ 10 % of the rice required for the scheme. The total economic cost losses in Punjab and Haryana amounted to USD 6.5 ± 2.2 billion in the fiscal year of 2012-2013 and USD 3.7 ± 1.2 billion in the fiscal year of 2013-2014. This economic loss estimate represents a very conservative lower limit based on

  15. Mode profile imaging and loss measurement for uniform and tapered single-mode 3D waveguides in diffusive photopolymer.

    PubMed

    Ye, Chunfang; Kamysiak, Keith T; Sullivan, Amy C; McLeod, Robert R

    2012-03-12

    We demonstrate single-mode uniform and parabolically tapered three-dimensional waveguides fabricated via direct-write lithography in diffusion-based photopolymers. Modulation of the writing power is shown to compensate Beer-Lambert absorption in the single-photon initiator and to provide precise control of modal tapers. A laminated sample preparation is introduced to enable full 3D characterization of these modal tapers without the need for sample polishing which is difficult for this class of polymer. The accuracy and repeatability of this modal characterization is shown to allow precise measurement of propagation loss from single samples. These testing procedures are used to demonstrate single-mode waveguides with 0.147 dB/cm excess propagation loss and symmetrical tapers up to 1:2.5 using 1.5 microwatts of continuous write power. PMID:22418540

  16. A comparison of peripheral marginal bone loss at dental implants measured with conventional intraoral film and digitized radiographs.

    PubMed

    Kamburoğlu, Kıvanç; Gülşahı, Ayşe; Genç, Yasemin; Paksoy, Candan Semra

    2012-06-01

    The purpose of the present study was to examine the effects of conventional and bone-condensing implantation techniques and time (6 and 12 months after implantation) on levels of marginal bone surrounding implants and to assess the level of agreement between measurements made using digitized intraoral images and film. The study group consisted of 14 healthy patients (9 female, 5 male; age range, 23-59 years; mean age, 41.1 years) with 28 single-tooth dental implants. In each patient, an implant was placed on one side using a conventional technique and on the opposite side using a bone-condensing technique. Film radiographs were taken at 6 and 12 months following implant placement and were digitized at 300 dpi and 600 dpi using a laser scanner. All scanned images were stored as both TIFF and JPEG files. A single observer twice measured distal and mesial marginal bone loss from film and digitized images. At the mesial site, there was a significant main effect of time (6 and 12 months after implantation) on the measurement of bone loss, F(1, 26) = 6.08, P = .02, but no significant main effect of implantation technique, F(1, 26) = 1.56, P = .223, and no significant interaction between time and technique, F(1, 26) = 2.09, P = .160. Similarly, at the distal site, there was a significant main effect of time on the measurement of bone loss, F(1, 26) = 14.1, P = .001, but no significant main effect of implantation technique, F(1, 26) = 1.21, P = .281. However, in contrast to the mesial site, there was also significant interaction between technique and time on the distal site, F(1, 26) = 4.974, P = .035. Intraobserver intraclass correlation coefficients and repeatability measurements showed high agreement for all image types. The bone-condensing technique resulted in greater marginal bone loss. Marginal bone measurements made using digitized intraoral images and conventional film showed high levels of agreement. PMID:20712442

  17. Generation of a Parabolic Trough Collector Efficiency Curve from Separate Measurements of Outdoor Optical Efficiency and Indoor Receiver Heat Loss

    SciTech Connect

    Kutscher, C.; Burkholder, F.; Stynes, J. K.

    2012-02-01

    The thermal efficiency of a parabolic trough collector is a function of both the fraction of direct normal radiation absorbed by the receiver (the optical efficiency) and the heat lost to the environment when the receiver is at operating temperature. The thermal efficiency can be determined by testing the collector under actual operating conditions or by separately measuring these two components. This paper describes how outdoor measurement of the optical efficiency is combined with laboratory measurements of receiver heat loss to obtain the thermal efficiency curve. This paper describes this approach and also makes the case that there are advantages to plotting collector efficiency versus the difference between the operating temperature and the ambient temperature at which the receiver heat loss was measured divided by radiation to a fractional power (on the order of 1/3 but obtained via data regression) - as opposed to the difference between operating and ambient temperatures divided by the radiation. The results are shown to be robust over wide ranges of ambient temperature, sky temperature, and wind speed.

  18. The WHO-DAS II: psychometric properties in the measurement of functional health status in adults with acquired hearing loss.

    PubMed

    Chisolm, Theresa H; Abrams, Harvey B; McArdle, Rachel; Wilson, Richard H; Doyle, Patrick J

    2005-01-01

    The World Health Organization's (WHO) Disability Assessment Scale II (WHO-DAS II) is a generic health-status instrument firmly grounded in the WHO's International Classification of Functioning, Disability and Health (WHO-ICF). As such, it assesses functioning for six domains: communication, mobility, self-care, interpersonal, life activities, and participation. Domain scores aggregate to a total score. Because the WHO-DAS II contains questions relevant to hearing and communication, it has good face validity for use as an outcome measure for audiologic intervention. The purpose of the present study was to determine the psychometric properties of the WHO-DAS II on a sample of individuals with adult-onset hearing loss, including convergent validity, internal consistency, and test-retest stability. Convergent validity was established by examining correlations between the WHO-DAS II (domain and total scores) and the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Hearing Aid Handicap for the Elderly (HHIE), two disease-specific measures, as well as with the Short Form-36 for veterans (SF-36V), a second generic measure. Data on all four measures were collected from 380 older individuals with adult-onset hearing loss who were not hearing aid users. The results of the convergent validity analysis revealed that the WHODAS II communication domain score was moderately and significantly correlated with scores on the APHAB and the HHIE. WHO-DAS II interpersonal and participation domain scores and the total scores were also moderately and significantly correlated with HHIE scores. These findings support the validity of using the WHO-DAS II for assessing activity limitations and participation restrictions of adult-onset hearing loss. Several WHO-DAS II domain scores and the total score were also significantly and moderately-markedly correlated with scores from the SF-36V. These findings support the validity of the WHO-DAS II as a generic health-status instrument

  19. Improved technique for measuring fecal energy loss in normal and malabsorbing humans.

    PubMed

    Zarling, E J; Ruchim, M A; Makino, D

    1986-01-01

    Fecal energy concentration is measured by bomb calorimetry on freeze-dried stool samples. Some of the energy-containing fecal compounds are volatile in the pH ranges of normal stool and hence may be lost during sample preparation. We found that significant amounts of volatile fatty acids and lactic acid are lost during lyophilization. Fecal alkalization caused an increase of 9.8% of measurable energy in stools from normal individuals and 25% in stools from patients with untreated exocrine pancreatic insufficiency. We conclude that previous reports of fecal energy concentration that did not use an alkalization procedure are probably underestimations. We recommend fecal alkalization before lyophilization in future measurements of fecal energy excretion. PMID:3941294

  20. Loss on Ignition: Measuring Soil Organic Carbon in Soils of the Sahel, West Africa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traditional methods of measuring soil organic carbon (SOC) are not adequate for accurate evaluation of C sequestration nor to meet environmental safety requirements. Methods that permit accurate assessment of SOC, which are environmentally healthy, and yet feasible for use in developing countries ar...

  1. Method for measuring the losses and loading of a quartz crystal microbalance.

    PubMed

    Kankare, Jouko; Loikas, Kari; Salomäki, Mikko

    2006-03-15

    A novel, experimentally simple, and highly sensitive method for measuring the loading of a quartz crystal resonator was developed. The method is based on the use of double-sideband suppressed-carrier modulated high-frequency signal, which is swept through the resonance range of the resonator. Induced current in the resonator is passed through a capacitor, and the voltage over the capacitor is demodulated on an analog multiplier. The phase and amplitude information is carried to the frequency-doubled modulation signal and measured on a conventional low-frequency two-phase lock-in amplifier. A complex dimensionless loading parameter is obtained from the experimental data by nonlinear model fitting. The real and complex parts of this loading parameter have a simple relationship with other parameters commonly used for characterizing the resonator loading. The performance of the method was demonstrated by measuring a series of different glycerol-water mixtures ranging from 0 up to 100% glycerol. The results were close to the shear acoustic impedance of these mixtures measured and calculated from their viscosities and densities. PMID:16536423

  2. Two-photon photoacoustics ultrasound measurement by a loss modulation technique

    NASA Astrophysics Data System (ADS)

    Lai, Yu-Hung; Chang, Chieh-Feng; Cheng, Yu-Hsiang; Sun, Chi-Kuang

    2013-03-01

    In this work, we investigated the principle of the two-photon absorption (TPA) detection with a loss modulation technique, and first demonstrated the existence of two-photon photoacoustics ultrasound excited by a femtosecond high repetition rate laser. By using the AO modulation with different modulation frequencies, we successfully create the beating of the light signal when the two arms of the beams are both spatial and temporal overlapping. The pulse train of the femtosecond laser causes the narrow band excitation, providing the frequency selectivity and sensitivity. Moreover, the pulse energy is no more than 15nJ/pulse, which is at least 3 orders of magnitude smaller than that of the nanosecond laser, and therefore prevents the thermal damage of the sample. With the help of lock-in detection and a low noise amplifier, we can separate the signal of two-photon absorption from one-photon absorption. We used an ultrasonic transducer to detect the response of the sample, and verified the existence of the two-photon photoacoustics ultrasound generating by the femtosecond laser. Several contrast agents, such as the black carbon solution, the fluorescence dye and the nano-particles, were used in the experiment. In the end, we demonstrated the application, two photo-acoustic imaging, which provides the high spatial resolution (<10μm) and large penetration depth (~1mm), to the simulated biological tissue. This is a milestone to develop the two-photon photoacoustics microscopy, which, in principle, has the great potential to achieve the in vitro and in vivo high resolution deep tissue imaging.

  3. A MONOLITHIC PREAMPLIFIER-SHAPER FOR MEASUREMENT LOSS AND TRANSITION RADIATION.

    SciTech Connect

    KANDASAMY,A.

    1999-11-08

    A custom monolithic circuit has been developed for the Time Expansion Chamber (TEC) of the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). This detector identifies particles by sampling their ionization energy loss (dE/dx) over a 3 cm drift space and by detecting associated transition radiation (TR) photons. The requirement of being simultaneously sensitive to dE/dx and TR events requires a dual-gain system. We have developed a compact solution featuring an octal preamplifier/shaper (P/S) IC with a split gain stage. The circuit, fabricated in 1.2 {micro}m CMOS process, incorporates a trans-impedance preamplifier and a 70 ns unipolar CR-RC{sup 4} shaper with ion tail compensation and active DC offset cancellation. Digitally selectable gain, peaking time, and tail cancellation as well as channel-by-channel charge injection and disable can be configured in the system via a 3-wire interface. The 3.5 x 5 mm{sup 2} die is packaged in a fine-pitch 64-pin PQFP. Equivalent input noise is less than 1500 rms electrons at a power dissipation of 30 mW per channel. On a sample of 2400 chips, the DC offset was 2.3 {+-} 3 mV rms without trimming. A chamber-mounted TEC-PS Printed Circuit Board (PCB) houses four PIS chips, on-board calibration circuit, and 64 analog differential line drivers which transmit the shaped pulses to crate-mounted flash ADC's. 7 m apart An RS-422 link provides digital configuration downloading and read back, and supplies the calibration strobe. The 24.6 cm x 9.5 cm board dissipates 8.5 W.

  4. Eddy Current Measurements of Corrosion and Metal Loss in Zircaloy Cladding with Ferromagnetic Crud

    SciTech Connect

    Yagnik, Suresh K.; Johnson, Duane P.; Kervinen, John A

    2004-08-15

    The routine method of monitoring Zircaloy cladding corrosion in nuclear fuel pools is based on eddy current (EC) measurements at a single high frequency in the range of 1-3 MHz. At this frequency the rf wave does not penetrate through the cladding wall and, ideally, the EC response can be correlated to the thickness of the oxide layer that separates the sensor head from the metal substrate. In practice, however, the cladding corrosion is often overestimated by this method due to the primary circuit corrosion products (or crud) that are deposited on the fuel rod surface. In addition, the crud, which is primarily nickel ferrite oxides, may significantly interfere with the EC response due to its ferromagnetic nature. We describe a two-frequency method with four-dimensional vector analyses of the EC response to more precisely assess the cladding corrosion. Two independent approaches for measuring the corrosion damage are suggested in this study. First, the four-dimensional data treatment enables a direct measure of the oxide thickness, even in the presence of ferromagnetic crud. Second, it can also provide a direct measure of the substrate wall thickness, and hence the degree of corrosion, provided the original wall thickness is known. By comparison, the approaches to crud correction currently available prove inadequate, especially if both the thickness and permeability of the crud deposits vary over the fuel rod surface, as is generally the case. The new method has been applied to inactive samples with and without the ferromagnetic crud effect. In the reported laboratory simulations, the oxide thickness and wall thinning were measured independently to within {+-}4 {mu}m, irrespective of unknown crud thickness and permeability.

  5. Anisotropic pitch angle distribution of ~100 keV microburst electrons in the loss cone: measurements from STSAT-1

    NASA Astrophysics Data System (ADS)

    Lee, J. J.; Parks, G. K.; Lee, E.; Tsurutani, B. T.; Hwang, J.; Cho, K. S.; Kim, K.-H.; Park, Y. D.; Min, K. W.; McCarthy, M. P.

    2012-11-01

    Electron microburst energy spectra in the range of 170 keV to 360 keV have been measured using two solid-state detectors onboard the low-altitude (680 km), polar-orbiting Korean STSAT-1 (Science and Technology SATellite-1). Applying a unique capability of the spacecraft attitude control system, microburst energy spectra have been accurately resolved into two components: perpendicular to and parallel to the geomagnetic field direction. The former measures trapped electrons and the latter those electrons with pitch angles in the loss cone and precipitating into atmosphere. It is found that the perpendicular component energy spectra are harder than the parallel component and the loss cone is not completely filled by the electrons in the energy range of 170 keV to 360 keV. These results have been modeled assuming a wave-particle cyclotron resonance mechanism, where higher energy electrons travelling within a magnetic flux tube interact with whistler mode waves at higher latitudes (lower altitudes). Our results suggest that because higher energy (relativistic) microbursts do not fill the loss cone completely, only a small portion of electrons is able to reach low altitude (~100 km) atmosphere. Thus assuming that low energy microbursts and relativistic microbursts are created by cyclotron resonance with chorus elements (but at different locations), the low energy portion of the microburst spectrum will dominate at low altitudes. This explains why relativistic microbursts have not been observed by balloon experiments, which typically float at altitudes of ~30 km and measure only X-ray flux produced by collisions between neutral atmospheric particles and precipitating electrons.

  6. Modeling Loss and Rebuilding of the Earth's Outer Zone Electrons and Comparison with Van Allen Probes Measurements

    NASA Astrophysics Data System (ADS)

    Hudson, M. K.; Kress, B. T.; Li, Z.; Paral, J.; Wiltberger, M. J.

    2014-12-01

    Quantifying the competition between radiation belt electron energization due to radial transport and loss to the magnetopause and to the atmosphere is critical to understanding the dynamic changes in outer zone radiation belt electron flux response to solar wind drivers. Plasmasheet electron injection, both due to enhanced convection and substorm dipolarization, provides a source population for generation of whistler mode chorus and seed population for local acceleration. We now have available ~22 months of unprecedented measurements in energy and pitch angle resolution of electrons spanning the energy range from injected plasmasheet to multi-MeV electrons from the twin Van Allen Probes spacecraft in near-equatorial plane elliptical orbits, with apogee at 5.8 Re; and two Balloon Array for Relativistic Radiation Belt Electron Losses (BARREL) campaigns during January-February 2013 and 2014, each establishing a longitudinal array of precipitation measurements extending to relativistic energies via measured Bremsstrahlung x-rays. In addition to this arsenal of data, a set of modeling tools has been developed to examine dynamics of electrons in the magnetosphere. These tools calculate electron trajectories in time-dependent magnetohydrodyanmic (MHD) fields using the Lyon-Fedder-Mobarry global MHD model coupled with the Rice Convection Model to determine the E and B field response to solar wind drivers. With these tools we can follow electron dynamics including response to Ultra Low Frequency (ULF) waves which cause radial transport and energization for inward radial gradient as well as enhanced loss to the magnetopause for outward gradient. These tools have been applied to date to the large equinoctial storms of fall 2012, spring and fall 2013, in addition to moderate storms during BARREL balloon campaigns in both winters 2013 and 2014. Isolated substorm response can clearly be identified for the latter, while plasmasheet injection of electrons during periods of strong

  7. Digital ac monitor

    DOEpatents

    Hart, George W.; Kern, Jr., Edward C.

    1987-06-09

    An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer.

  8. Large signal dielectric losses in electrostrictive materials

    NASA Astrophysics Data System (ADS)

    Robinson, Harold C.

    2000-06-01

    The dielectric loss factor tan (delta) is a critical parameter in transducer design and performance prediction, as it is directly related to the electrical energy lost to Joule heating. A method for calculating the equivalent loss factor of 'quasi linear' materials from a measured major polarization vs. field loop by extending the standard definition of tan (delta) for a linear lossy capacitor to nonlinear materials is presented. To extract effective loss tangents for minor loops from the major loops, an area correction algorithm was implemented. This algorithm proves to be nearly exact for all bias and drive levels in the case of an ideal linear capacitor. In most cases, the effective tan (delta) calculated from a major loop agrees fairly well with that calculated from a directly measured minor loop. Finally, the behavior of the loss tangent as a function of the dc bias field, ac drive field, prestress level and temperature will be examined. It shall be shown that, in general, the effective loss factor of lead magnesium niobate-lead titanate decreases with increasing temperature, consistent with its transition from a piezoelectric to an electrostrictive material, but increases with prestress. At a fixed temperature and prestress level, the loss factor increases as the bias or drive levels decrease. However, at certain bias levels, the loss tangent is practically the same, regardless of the drive level.

  9. Measurement of the sizes of circumstellar dust shells around evolved stars with high mass loss rates

    NASA Technical Reports Server (NTRS)

    Phillips, T. G.; Knapp, G. R.

    1992-01-01

    The research supported by the NASA ADP contract NAG5-1153 has been completed. The attached paper, which will be submitted for publication in the Astrophysical Journal in January 1992, presents the results of this work. Here is a summary of the project and its results. A set of computer programs was developed to process the raw 60 micron and 100 micron IRAS survey data. The programs were designed to detect faint extended emission surrounding a bright unresolved source. Candidate objects were chosen from a list of red giant stars and young planetary nebulae which have been detected in millimeter/submillimeter lines of CO. Of the 279 stars examined, 55 were resolved at 60 microns. The principle results of the study are given. The average age for the shells surrounding the 9 Mira-type stars which are extended is 6 x 10(exp 4) yr. This suggests that the period during which these stars lose mass lasts for approx 10(exp 5) yr. The oldest shell found surrounds U Ori, and the youngest surrounds Mira itself. Some shells appear to be detached from the central star. This phenomenon is more common among older stars, suggesting that the mass loss becomes more episodic as the star sheds its envelope. Although all 8 stars less distant than 200 pc are resolved in the IRAS 60 micron data, 29 stars within 500 pc were not. These stars probably have younger circumstellar shells than those which were resolved. Almost all the carbon stars with distances of 500 pc or less have resolved shells, while only 1/2 of the oxygen-rich stars do. The resolved carbon star shells also are older on average than the oxygen-rich ones. These facts imply that carbon stars have been losing mass for a longer period, on average, than oxygen-rich red giants. Large circumstellar shells tend to be found at large distances from the galactic plane, confirming that the ISM density limits the size to which a dust shell can grow. Surprisingly, even very large shells seem to be nearly spherical, and do not appear to

  10. Measurement of the loss cone flux of energetic electon ---Detailed Design Considerations

    NASA Astrophysics Data System (ADS)

    Sullivan, James; Cooke, David; Ginet, Gregory

    Today the major task is the development of space and ground means of monitoring near-Earth space environment and terrestrial crust for the forecast of the dangerous phenomena connected with the influence of natural and antropogeneous activity on the environment. The monitoring should be based on the realization of regular measurements and observation of the most important parameters describing the condition of the environment and its change as a result of natural and antropogeneous influences. The global and operative monitoring of the condition of the top atmosphere, ionosphere and terrestrial crust alongside with the registration of the antropogeneous factors can provide completeness of the information which is necessary for observation, research, control and forecast of the dangerous phenomena of natural and antropogeneous origins. For its realization it is necessary to solve a complex of problems connected to the development of techniques and means of the control, both preparation and organization of observation systems and measurements. The problem of the development of high precision means and methods of global monitoring of geophysical, geodynamic and seismic phenomena with the help of ground-space methods is currently quite acute. The application of global navigating satellite systems together with the methods of the solution of return radio translucence tasks allow to do long and regular measurements, which enable to investigate the temporary and spatial regularities occurring in the Earth ionosphere. Received as a result of the inversion of navigating measurements the high-altitude profiles of the distribution of the electron concentration can form a basis for studying such existential regularities of the ionosphere. On the basis of the results of data processing received with the use of navigating systems, it has been confirmed that above an epicenter of the future earthquake there is an infringement of an existential course of electron concentration of

  11. Loss-tolerant hybrid measurement test of CHSH inequality with weakly amplified N00N states

    NASA Astrophysics Data System (ADS)

    Töppel, Falk; Stobińska, Magdalena

    2015-02-01

    Although our understanding of Bell’s theorem and experimental techniques to test it have improved over the last 40 years, thus far all Bell tests have suffered at least from the detection or the locality loophole. Most photonic Bell tests rely on inefficient discrete-outcome measurements, often provided by photon counting detection. One possible way to close the detection loophole in photonic Bell tests is to involve efficient continuous-variable measurements instead, such as homodyne detection. Here, we propose a test of the Clauser-Horne-Shimony-Holt inequality that applies photon counting and homodyne detection on weakly amplified two-photon N00N states. The scheme suggested is remarkably robust against experimental imperfections and suits the limits of current technology. As amplified quantum states are considered, our work also contributes to the exploration of entangled macroscopic quantum systems. Further, it may constitute an alternative platform for a loophole-free Bell test, which is also important for quantum-technological applications.

  12. Measurement of systolic pressure variation during graded volume loss using simple tools on Datex Ohmeda S/5 monitor.

    PubMed

    Durga, Padmaja; Jonnavittula, Nirmala; Muthuchellappan, Radhakrishnan; Ramachandran, Gopinath

    2009-04-01

    Direct invasive arterial monitoring is performed routinely for all major neurosurgical procedures. Systolic pressure variation (SPV) used, independently or in combination with central venous pressure (CVP) allows optimal fluid management in hypovolemia and hemorrhage. This study aims to quantify SPV during graded hypovolemia using the simple technique described by Gouvea and Gouvea using Datex Ohmeda S/5, and to compare its reliability relative to other hemodynamic indicators of hypovolemia. Twenty anesthetized neurosurgical patients of ASA grade I and II patients were administered furosemide 0.5 mg/kg intravenously to obtain graded volume loss in the form of urine output. Invasive arterial pressure from radial artery and CVP were monitored using Datex OhmedaS/5 (Finland). Invasive arterial pressure label was changed to pulmonary artery label with the scale appropriate for arterial pressure. The trace was frozen in the wedge mode to reduce the sweep speed and the cursor was used to measure SPV and pulse pressure variation (PPV). Heart rate, systolic blood pressure, diastolic blood pressure, CVP at zero end-expiratory pressure, SPV and PPV are measured at baseline, and after a urine output of 200 and 500 mL. There was a significant correlation between volume loss and CVP, SPV, and PPV. The area under the curve of receiver operating characteristic analysis was >0.75 for CVP, SPV, and PPV. SPV of 7.5 mm Hg and a change of SPV by 4.5 mm Hg, a PPV of 4.5 and change in PPV by 2.5 mm Hg were the best cut-off values that corresponded to a volume change of 500 mL. This simple method enabled calculation of SPV without the computerized modules, and detected volume loss comparable to CVP. PMID:19295396

  13. Seasonal measurements of total OH reactivity fluxes, total ozone loss rates and missing emissions from Norway spruce in 2011

    NASA Astrophysics Data System (ADS)

    Nölscher, A. C.; Bourtsoukidis, E.; Bonn, B.; Kesselmeier, J.; Lelieveld, J.; Williams, J.

    2012-10-01

    Numerous reactive volatile organic compounds (VOCs) are emitted into the atmosphere by vegetation. Most biogenic VOCs are highly reactive towards the atmosphere's most important oxidant, the hydroxyl (OH) radical. One way to investigate the chemical interplay between biosphere and atmosphere is through the measurement of total OH reactivity, the total loss rate of OH radicals. This study presents the first determination of total OH reactivity emission rates (measurements via the Comparative Reactivity Method) based on a branch cuvette enclosure system mounted on a Norway spruce (Picea abies) throughout spring, summer and autumn 2011. In parallel separate VOC emission rates were monitored by a Proton Transfer Reaction-Mass Spectrometer (PTR-MS), and total ozone (O3) loss rates were obtained inside the cuvette. Total OH reactivity emission rates were in general temperature and light dependent, showing strong diel cycles with highest values during daytime. Monoterpene emissions contributed most, accounting for 56-69% of the measured total OH reactivity flux in spring and early summer. However, during late summer and autumn the monoterpene contribution decreased to 11-16%. At this time, a large missing fraction of the total OH reactivity emission rate (70-84%) was found when compared to the VOC budget measured by PTR-MS. Total OH reactivity and missing total OH reactivity emission rates reached maximum values in late summer corresponding to the period of highest temperature. Total O3 loss rates within the closed cuvette showed similar diel profiles and comparable seasonality to the total OH reactivity fluxes. Total OH reactivity fluxes were also compared to emissions from needle storage pools predicted by a temperature-only dependent algorithm. Deviations of total OH reactivity fluxes from the temperature-only dependent emission algorithm were observed for occasions of mechanical and heat stress. While for mechanical stress, induced by strong wind, measured VOCs could

  14. Time integrated x-ray measurments of the very energetic electron end loss profile in TMX-U

    SciTech Connect

    Osher, J.E.; Fabyan, J.

    1984-09-14

    The time-integrated 2-D profile of the thick-target bremsstrahlung produced by energetic end loss electrons has been measured during ECRH operation of TMX-U. Sheets of x-ray film and/or arrays of thermoluminescent dosimeters were placed on the outside of the end tank end wall to measure the relative spatial x-ray profile, with locally added filters of Pb to determine the effective mean x-ray energy. The purpose of this simple survey diagnostic was to allow deduction of the gross features of the ECRH region. The electron source functions needed to fit the x-ray data were modeled for various anchor cell radial distributions mapped along magnetic field lines to the elliptical plasma potential control plates or the Al end walls. The data are generally consistent with (1) major ECR heating in the central 25-cm-diam core, (2) a mean ECRH electron loss energy of 420 keV, and (3) an ECRH coupling efficiency to these hot electrons of greater than or equal to 10%.

  15. Temperature and strain measurements using the power, line-width, shape, and frequency shift of the Brillouin loss spectrum

    NASA Astrophysics Data System (ADS)

    Bao, Xiaoyi; Smith, Jeffrey; Brown, Anthony W.

    2002-09-01

    A Brillouin scattering based fiber sensor system has been developed by our Fiber Optics Group for the structural monitoring and civil engineering related applications. In this paper, the Brillouin loss spectrum has been characterized in terms of its center frequency, peak power, line-width and shape. These parameters have been considered as a function of the input pump and probe laser powers, the pump pulse duration, strain and temperature. The measurement accuracy has been studied at different Brillouin frequency steps to study the uncertainty of the Brillouin frequency, line-width, peak power and shape factor vs. signal to noise ratio, so that we can optimize the system performance. Characterization of the Brillouin loss spectrum led to the development of an innovative technique to measure the strain and temperature simultaneously using the strain and temperature dependence on the peak power in conjunction with the Brillouin frequency for the single mode fiber with 3m spatial resolution, 3°C temperature resolution and 200 me (mm/m) strain accuracy.

  16. Novel apparatus to measure hyperthermal heavy ion damage to DNA: Strand breaks, base loss, and fragmentation

    SciTech Connect

    Sellami, L.; Lacombe, S.; Hunting, D.; Wagner, R. J.; Huels, M. A.

    2007-08-15

    We have developed a novel apparatus that allows us to irradiate nonvolatile organic films of high mass (1-100 {mu}g range) spread out over a large surface area (42 cm{sup 2}) with low energy (kT-100 eV) heavy ions and to quantitatively analyze the film substance via standard biochemical techniques afterwards. Here we discuss the details of the apparatus and method and show that it allows us to measure substantial damage to double stranded DNA molecules (plasmids) and its fundamental subunits induced by heavy ions with unprecedented low energies, i.e., 2.5 eV/amu; these energies correspond to track end energies of stopping ions or secondary ions created along primary ion tracks. We find that hyperthermal Ar{sup +} ions interacting with plasmid DNA will lead to the formation of single and double strand breaks, as well as fragmentation of nucleosides, which also involve chemical modifications and site specific rupture along the N1-C1 glycosidic bond, resulting in base release. In cells, such localized clustered damage will enhance the severity of DNA strand lesions, thus making them harder to repair.

  17. Development of a microfabricated optical bend loss sensor for distributive pressure measurement.

    PubMed

    Wang, Wei-Chih; Ledoux, William R; Huang, Chu-Yu; Huang, Cheng-Sheng; Klute, Glenn K; Reinhall, Per G

    2008-02-01

    A flexible high-resolution sensor capable of measuring the distribution of pressure beneath the foot via a microfabricated optical waveguide system is presented. The uniqueness of the system is in its batch fabrication process, which involves a microfabrication molding technique with polydimethylsiloxane (PDMS) as the optical medium. The sensor manufacturing technique is described in detail, the optical performance of the waveguides is quantified and the effect of using a matching fluid to improve fiber-coupling efficiency is demonstrated. Mechanical loading tests were performed on a 4 x 4 array with a 2-mm spacing between sensing elements. Loading displacement curves were obtained using a 0 to 0.4 mm triangle loading profile. A force of 0.28 N applied to one of the sensing elements produced a displacement of a 0.325 mm and 39% change in the output light intensity. Multiple loadings were conducted to demonstrate the repeatability of the sensor. A force image algorithm with a two-layer neural network system was used to identify four load magnitudes and four different shaped applicators. All four shapes were successfully identified with the neural network. PMID:18269997

  18. Spatial variations in ac susceptibility and microstructure for the YBa2Cu3O(7-x) superconductor and their correlation with room-temperature ultrasonic measurements

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Deguire, Mark R.; Dolhert, Leonard E.; Hepp, Aloysius F.

    1991-01-01

    The spatial (within-sample) uniformity of superconducting behavior and microstructure in YBa2Cu3O(7-x) specimens over the pore fraction range of 0.10 to 0.25 was examined. The viability of using a room-temperature, nondestructive characterization method (ultrasonic velocity imaging) to predict spatial variability was determined. Spatial variations in superconductor properties were observed for specimens containing 0.10 pore fraction. An ultrasonic velocity image constructed from measurements at 1 mm increments across one such specimen revealed microstructural variation between edge and center locations that correlated with variations in alternating-current shielding and loss behavior. Optical quantitative image analysis on sample cross-sections revealed pore fraction to be the varying microstructural feature.

  19. Measurement of seepage losses and chemical export from waste lagoons at animal feeding operations

    NASA Astrophysics Data System (ADS)

    Ham, J. M.; DeSutter, T. M.

    2001-05-01

    Whole-lagoon seepage rates were measured from 20 lagoons in Kansas using water balance techniques. Study sites included cattle feedlots, swine facilities, and one dairy. Seepage rates ranged from 0.2 mm/day to 2.4 mm/day with and overall average of 1.2 mm/day. Analysis of lagoon effluent (58 samples from 38 sites) indicated large differences in lagoon chemistry between locations. Ammonium nitrogen (NH4-N), which accounted for over 99 percent of the soluble nitrogen, ranged from 10 ppm to 3500 ppm. On average, nitrogen concentrations in swine lagoons were about five times higher than those at cattle feedlots. The chemical flux density (flux boundary condition) was estimated from the seepage rate and the corresponding waste chemistry data from each lagoon. Results showed that ammonium-N export was between 0.02 and 1.06 kg NH4-N m-2 yr^{-1} with an overall average of about 0.3 kg NH4-N m^{-2} yr^{-1}$ . Similar data are available for other soluble compounds. Soil cores were collected beneath eight lagoons that had been operated from 12 to 25 years. Results showed that NH4-N was strongly adsorbed by the soil clay particles and that nitrogen concentrations often decreased to background levels at 3 m beneath the lagoon. Other ions, such as chloride, penetrated to much lower depths at all locations. The 'reservoir' of NH4-N that exists beneath older lagoons could convert to nitrate and move to lower depths after lagoon closure. Data suggest that the properties if the soil beneath lagoons, the concentration of the waste, the seepage rate, and the depth to groundwater are the crucial factors that affect the risk of groundwater contamination.

  20. Isotopic composition of carbon dioxide from a boreal forest fire: Inferring carbon loss from measurements and modeling

    USGS Publications Warehouse

    Schuur, E.A.G.; Trumbore, S.E.; Mack, M.C.; Harden, J.W.

    2003-01-01

    Fire is an important pathway for carbon (C) loss from boreal forest ecosystems and has a strong effect on ecosystem C balance. Fires can range widely in severity, defined as the amount of vegetation and forest floor consumed by fire, depending on local fuel and climatic conditions. Here we explore a novel method for estimating fire severity and loss of C from fire using the atmosphere to integrate ecosystem heterogeneity at the watershed scale. We measured the ??13C and ??14C isotopic values of CO2 emitted from an experimental forest fire at the Caribou-Poker Creek Research Watershed (CPCRW), near Fairbanks, Alaska. We used inverse modeling combined with dual isotope near measurements of C contained in aboveground black spruce biomass and soil organic horizons to estimate the amount of C released by this fire. The experimental burn was a medium to severe intensity fire that released, on average, about 2.5 kg Cm-2, more than half of the C contained in vegetation and soil organic horizon pools. For vegetation, the model predicted that approximately 70-75% of pools such as needles, fine branches, and bark were consumed by fire, whereas only 20-30% of pools such as coarse branches and cones were consumed. The fire was predicted to have almost completely consumed surface soil organic horizons and burned about half of the deepest humic horizon. The ability to estimate the amount of biomass combusted and C emission from fires at the watershed scale provides an extensive approach that can complement more limited intensive ground-based measurements.

  1. Images processing and flow measurement applied to the thermographic analysis of heat-losses in boilers' isolation

    NASA Astrophysics Data System (ADS)

    Hurtado, Manuel A.; Benítez, Hernán; Loaiza, Humberto; Millán, Jaime; González, Jesus A.; Ibarra-Castanedo, Clemente

    2007-04-01

    Infrared thermography is a non-contact evaluation technique which allows not only the registration of the temperature distribution on a surface, but also the calculation of the amount of heat flowing through it. Boilers are important for industry and the quantification of the heat losses is beneficial to avoid fuel waste. The present work suggests a methodology to calculate the thermic flow through boiler's isolation surfaces, using thermic images. With this, it is possible to find the flow by using a thermogram taking into consideration: the thermogram's range, knowing the camera's FOV, surface's emmisivity and characteristic length, object-to-camera distance, environmental temperature, and the assigned grey-level calibration curve to determined temperature range. A software tool to upload and process the information was developed. This tool can calculate the surface's average convection coefficient hc by using empiric correlations developed for common geometries and heat transfer equations to calculate the thermic flow. To test the technique functioning, the information given by the software tool was compared to the data given by the heat flow measurement thermal sensor. This comparison showed a 3% error range of relative error. The final validation was made on a waterwall-boiler's home isolated walls and the highest error obtained was close to 15%. Regardless the calibration curve was found under laboratory conditions and the empiric correlations to calculate hc are for isometric surfaces, the methodology presented a good performance. This then is a first step to quantify the global heat losses on boiler's isolation surfaces.

  2. Evaporative losses of vacuum-compatible oils through labyrinth seals

    NASA Astrophysics Data System (ADS)

    Anderson, M. J.; Freeman, S.; Roberts, E. W.

    2003-09-01

    Following a literature review to assess the theoretical and experimental methods used to evaluate fluid losses via labyrinth seals, an experimental programme was carried out to measure these losses. A model derived by ESTL provided the best correlation with experimental oil losses and an effusion cell approach was identified as the most appropriate method to assess the effectiveness of labyrinth seals for three space oils, ie Krytox 143AC, Nye 186B and Nye 2001A. The selection of these fluids enabled a relatively wide range of vapour pressures to be investigated in the experimental programme using effusion cells of different geometries. The test results were compared with the ESTL oil evaporation model and it was found that the evaporative losses from Nye 186B and HVAC25/9 were within an order of magnitude of predictions. Losses from Nye 2001a were larger than predictions.

  3. Hearing Loss

    MedlinePlus

    ... version of this page please turn Javascript on. Hearing Loss What is Hearing Loss? Hearing loss is a common problem caused by ... sec Click to watch this video Types of Hearing Loss Hearing loss comes in many forms. It can ...

  4. Is the medical loss ratio a good target measure for regulation in the individual market for health insurance?

    PubMed

    Karaca-Mandic, Pinar; Abraham, Jean M; Simon, Kosali

    2015-01-01

    Effective January 1, 2011, individual market health insurers must meet a minimum medical loss ratio (MLR) of 80%. This law aims to encourage 'productive' forms of competition by increasing the proportion of premium dollars spent on clinical benefits. To date, very little is known about the performance of firms in the individual health insurance market, including how MLRs are related to insurer and market characteristics. The MLR comprises one component of the price-cost margin, a traditional gauge of market power; the other component is percent of premiums spent on administrative expenses. We use data from the National Association of Insurance Commissioners (2001-2009) to evaluate whether the MLR is a good target measure for regulation by comparing the two components of the price-cost margin between markets that are more competitive versus those that are not, accounting for firm and market characteristics. We find that insurers with monopoly power have lower MLRs. Moreover, we find no evidence suggesting that insurers' administrative expenses are lower in more concentrated insurance markets. Thus, our results are largely consistent with the interpretation that the MLR could serve as a target measure of market power in regulating the individual market for health insurance but with notable limited ability to capture product and firm heterogeneity. PMID:24123608

  5. Geometrical effect on the measurement of stopping power: Angle-dependent energy loss of 7-MeV protons in metallic and organic thin foils

    SciTech Connect

    Ishiwari, R.; Shiomi, N.; Sakamoto, N.

    1982-05-01

    Energy losses of 7-MeV protons in metallic and organic thin foils have been obtained as a function of emergence angles. Angular distributions due to multiple scattering have been also measured. The energy loss is found to increase for all targets with increasing emergence angles. The increase of the energy loss cannot be explained by the following three effects: (1) the increase of the target thickness caused by the deflection of the particle, (2) the increase of the path length due to multiple scattering with atomic nuclei, and (3) the energy transfer to the recoil nuclei during the multiple-scattering process. From this consideration, the observed increase of the energy loss with increasing emergence angle is concluded to be due to a hitherto unknown effect. This effect is very likely the dependence of the energy loss on the average impact parameter with the atomic nucleus.

  6. AC magnetohydrodynamic microfluidic switch

    SciTech Connect

    Lemoff, A V; Lee, A P

    2000-03-02

    A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. This type of switch can be used to produce complex fluidic routing, which may have multiple applications in {micro}TAS.

  7. ACS Symposium Support

    SciTech Connect

    Kenneth D. Jordan

    2010-02-20

    The funds from this DOE grant were used to help cover the travel costs of five students and postdoctoral fellows who attended a symposium on 'Hydration: From Clusters to Aqueous Solutions' held at the Fall 2007 American Chemical Society Meeting in Boston, MA, August 19-23. The Symposium was sponsored by the Physical Chemistry Division, ACS. The technical program for the meeting is available at http://phys-acs.org/fall2007.html.

  8. Individual Beam Size And Length Measurements at the SLC Interaction Point Derived From the Beam Energy Loss During a Beam Beam Deflection Scan

    SciTech Connect

    Raimondi, P.; Field, R.Clive; Phinney, N.; Ross, M.C.; Slaton, T.; Traller, R.; /SLAC

    2011-08-26

    At the Interaction Point (IP) of the SLC Final Focus, beam-beam deflection scans routinely provide a measurement of the sum in quadrature of the electron and positron transverse beam sizes, but no information on the individual beam sizes. During the 1996 SLC run, an upgrade to the Final Focus beam position monitor system allowed a first measurement of the absolute beam energy loss of both beams on each step of the deflection scan. A fit to the energy loss distributions of the two beams provides a measurement not only of the individual transverse beam sizes at the IP but also of the individual bunch lengths.

  9. Investigation of magnetic spin glass property in La{sub 0.5}Bi{sub 0.5}MnO{sub 3} sample using non-linear AC susceptibility measurements

    SciTech Connect

    Kumar, Punith V. Manju, M. R. Dayal, Vijaylakshmi

    2014-04-24

    We present a comprehensive study on origin of Spin Glass (SG) property in polycrystalline La{sub 0.5}Bi{sub 0.5}MnO{sub 3} perovskite oxide using linear and higher order ac susceptibility (χ) measurements. The third order harmonic susceptibility (χ{sub 3}) vs. temperature (K) with varying magnetic fields from 0.95 to 9.45 Oe and the divergence in their χ{sub 3} (max) allows us to infer the SG behavior occurring in the sample possibly due to co-operative freezing of the spins.

  10. Channeling energy loss of He 2+ in Si by transmission and back-scattering measurements: Experiments and computer modeling

    NASA Astrophysics Data System (ADS)

    Lulli, G.; Albertazzi, E.; Bentini, G. G.; Bianconi, M.; Lotti, R.

    2002-06-01

    Path-dependent electronic stopping of 3.35 MeV He 2+ ions in Si, is investigated by Rutherford back-scattering channeling in Si/SiO 2 wafers and transmission energy loss measurements in thin (1 1 0) membranes. A model which makes use of the 3-D Si electron density to calculate the stopping due to valence electrons, and the program convolution approximation for swift particles (CASP) to calculate the stopping due to core electrons, has been introduced into a Monte Carlo code for the simulation of channeling. The only adjustment allowed is the normalization to the empirical random stopping. An agreement of simulations and experiments within ±10-15% is obtained if both valence and core electron stopping components are scaled in the normalization procedure. To perform a significant comparison with the results obtained by a full atomic (CASP) model, we have also used a different normalization scheme, keeping the core component fixed and scaling only the valence electron contribution. In this case the results of the solid model, although slightly less accurate, become very similar to those obtained with the free-atom model.

  11. Measurement of Absolute Excitation Cross Sections in Highly-Charged Ions Using Electron Energy Loss and Merged Beams

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Smith, Steven J.; Lozano, J.

    2002-01-01

    There is increasing emphasis during this decade on understanding energy balance and phenomena observed in high electron temperature plasmas. The UV spectral return from FUSE, the X-ray spectral return from the HETG on Chandra and the LETGS 011 XMM-Newton are just beginning. Line emissions are almost entirely from highly-charged ions (HCIs) of C, N, 0, Ne, Mg, S, Si, Ca, and Fe. The Constellation-X mission will provide X-ray spectroscopy up to photon energies of 0.12 nm (10 keV) where primary line emitters will be HCIs. A variety of atomic parameters are required to model the stellar and solar plasma. These include cross sections for excitation, ionization, charge-exchange, X-ray emission, direct and indirect recombination, lifetimes and branching ratios, and dependences on l, m mixing by external E and B fields. In almost all cases the atomic quantities are calculated, and few comparisons to experiment have been carried out. Collision strengths and Einstein A-values are required to convert the observed spectral intensities to electron temperatures and densities in the stellar plasma. The JPL electron energy-loss and merged beam approach has been used to measure absolute collision strengths in a number of ions, with critical comparison made to the best available theories.

  12. Longitudinal Inter-Comparison of Modeled and Measured West Greenland Ice Sheet Meltwater Runoff Losses (2004-2014)

    NASA Astrophysics Data System (ADS)

    Moustafa, S.; Rennermalm, A. K.; Tedesco, M.; Mote, T. L.; Koenig, L.; Smith, L. C.; Hagedorn, B.; Overeem, I.; Sletten, R. S.; Mikkelsen, A. B.; Hasholt, B.; Hall, D. K.

    2015-12-01

    Increased surface meltwater runoff, that exits the Greenland ice sheet (GrIS) margin via supra-, en-, and sub-glacial drainage networks into fjords, pro-glacial lakes and rivers, accounts for half or more of total mass loss. Despite its importance, modeled meltwater runoff fluxes are poorly constrained, primarily due to a lack of direct in situ observations. Here, we present the first ever longitudinal (north-south) inter-comparison of a multi-year dataset (2004-2014) of discharge for four drainage basins - Watson, Akuliarusiarsuup Kuua, Naujat Kuat, and North Rivers - along West Greenland. These in situ hydrologic measurements are compared with modeled runoff output from Modèle Atmosphérique Régional (MAR) regional climate model, and the performance of the model is examined. An analysis of the relationship between modeled and actual ice sheet runoff patterns is assessed, and provides insight into the model's ability to capture inter-annual and intra-annual variability, spatiotemporal patterns, and extreme melt events. This study's findings will inform future development and parameterization of ice sheet surface mass balance models.

  13. Energy loss measurements of 63Cu, 28Si and 27Al heavy ions crossing thin Polyvinylchloride (PVC) foil

    NASA Astrophysics Data System (ADS)

    Dib, A.; Ammi, H.; Guesmia, A.; Msimanga, M.; Mammeri, S.; Hedibel, M.; Guedioura, B.; Pineda-Vargas, C. A.

    2015-11-01

    Experimental stopping data of, 63Cu, 28Si and 27Al heavy ions in thin Polyvinylchloride (H3C2Cl1) foil have been obtained over the 0.045-0.50 MeV/nucleon energy range. The measured energy losses were carried out by Heavy Ion Elastic Recoil Detection Analysis (HI-ERDA) technique coupled with time of flight (ToF) spectrometer. A continuous stopping power data obtained in this work are well fitted by our proposed semi-empirical formula and the results are compared to those calculated by LSS formula or generated by SRIM-2013 and MSTAR predictions. Calculations using our formula agree well with the obtained experimental stopping powers, while the LSS formula underestimates the experimental data in the whole investigated energy range. In this work a simple expression for electronic stopping power of heavy ions at low energy in solid targets is introduced. This formula is based on the Firsov and Lindhard-Sharff stopping power models with a small modification made to the original expression, by incorporating the effective charge of moving ions concept and with exponential fit function.

  14. Attenuation measurement of very low-loss dielectric waveguides by the cavity resonator method in the millimeter/submillimeter wavelength range

    NASA Astrophysics Data System (ADS)

    Shimabukuko, F. I.; Yeh, C.

    1989-03-01

    A dielectric waveguide shorted at both ends is constructed as a cavity resonator. By measuring the Q of this cavity, one can determine the attenuation constant of the guided mode on this dielectric structure. The complex permittivity of the dielectric waveguide material can also be derived from these measurements. Measurement were made at Ka-band for dielectric waveguides constructed of nonpolar, low-loss polymers such as Teflon, polypropylene, polyethylene, polyethylene, and Rexolite.

  15. Ac electrode diagnostics in ac-operated metal halide lamps

    NASA Astrophysics Data System (ADS)

    Luijks, G. M. J. F.; van Esveld, H. A.; Nijdam, S.; Weerdesteijn, P. A. M.

    2008-07-01

    A diagnostic technique is presented to determine the electrode work function in ac-operated metal halide lamps. The heart of the experimental set-up is a high-speed photodiode array detector, which is able to follow real-time variations of electrode tip temperature and near-electrode plasma emissions in ac-operated experimental YAG lamps, enabling discrimination between the anode and cathode effects. Electrode tip temperature ripples have been measured for 100 Hz square wave operation and simulated with an existing electrode model. By using the electrode work function as main fit parameter for the simulations it is found that the measured cooling effect of the electrode tip in a NaTlDy-iodide lamp is caused by a gas-phase emitter effect of Dy. It is concluded that Dy coverage of the electrode tip causes an effective work function reduction of 0.3 eV at 100 Hz square wave operation, considerably less than the 1.0 eV reduction measured earlier for dc operation.

  16. Neutral Particle Analyzer Vertically Scanning Measurements of MHD-induced Energetic Ion Redistribution or Loss in the National Spherical Torus Experiment

    SciTech Connect

    S.S. Medley, R. Andre, R.E. Bell, D.S. Darrow, C.W. Domier, E.D. Fredrickson, N.N. Gorelenkov, S.M. Kaye, B.P. LeBlanc, K.C. Lee, F.M. Levinton, D. Liu, N.C. Luhmann, Jr., J.E. Menard, H. Park, D. Stutman, A.L. Roquemore, K. Tritz, H. Yuh and the NSTX Team

    2007-11-15

    Observations of magneto-hydro-dynamic (MHD) induced redistribution or loss of energetic ions measured using the vertically scanning capability of the Neutral Particle Analyzer diagnostic on the National Spherical Torus Experiment (NSTX) are presented along with TRANSP and ORBIT code analysis of the results. Although redistribution or loss of energetic ions due to bursting fishbone-like and low-frequency (f ~ 10 kHz) kinktype MHD activity has been reported previously, the primary goal of this work is to study redistribution or loss due to continuous Alfvénic (f ~ 20 – 150 kHz) modes, a topic that heretofore has not been investigated in detail for NSTX plasmas. Initial indications are that the former drive energetic ion loss whereas the continuous Alfvénic modes only cause redistribution and the energetic ions remain confined.

  17. Ac-Induced Instability at the Xanthophyllic Locus of Tomato

    PubMed Central

    Peterson, P. W.; Yoder, J. I.

    1993-01-01

    To detect genomic instability caused by Ac elements in transgenic tomatoes, we used the incompletely dominant mutation Xanthophyllic-1 (Xa-1) as a whole plant marker gene. Xa-1 is located on chromosome 10 and in the heterozygote state causes leaves to be yellow. Transgenic Ac-containing tomato plants which differed in the location and number of their Ac elements were crossed to Xa-1 tester lines and F(1) progeny were scored for aberrant somatic sectoring. Of 800 test and control F(1) progeny screened, only four plants had aberrantly high levels of somatic sectors. Three of the plants had twin sectors consisting of green tissue adjacent to white tissue, and the other had twin sectors comprised of green tissue adjacent to tissue more yellow than the heterozygote background. Sectoring was inherited and the two sectoring phenotypes mapped to opposite homologs of chromosome 10; the green/yellow sectoring phenotype mapped in coupling to Xa-1 while the green/white sectoring phenotype mapped in repulsion. The two sectoring phenotypes cosegregated with different single, non-rearranged Acs, and loss of these Acs from the genome corresponded to the loss of sectoring. Sectoring was still observed after transposition of the Ac to a new site which indicated that sectoring was not limited to a single locus. In both sectored lines, meiotic recombination of the sectoring Ac to the opposite homolog caused the phenotype to switch between the green/yellow and the green/white phenotypes. Thus the two different sectoring phenotypes arose from the same Ac-induced mechanism; the phenotype depended on which chromosome 10 homolog the Ac was on. We believe that the twin sectors resulted from chromosome breakage mediated by a single intact, transposition-competent Ac element. PMID:8394266

  18. POPEYE: A river-load oriented model to evaluate the efficiency of environmental policy measures for reducing phosphorus losses

    NASA Astrophysics Data System (ADS)

    Trevisan, Dominique; Quétin, Philippe; Barbet, Denis; Dorioz, Jean Marcel

    2012-07-01

    SummaryWatershed losses of phosphorus (P) have been a topic of concern for water resource managers over recent decades. To evaluate environmental policies or before implementing mitigation options at the watershed (catchment area) scale, stakeholders often need to analyze the patterns of point and diffuse sources of phosphorus. This information is often not easy to obtain in field conditions. Several statistical modeling approaches have been developed in recent years to respond to this basic operational demand. Point and diffuse sources are often evaluated from power functions established between phosphorus concentration and water discharge. Such models do not explicitly account for in-stream processes which control P concentrations in the hydrographic network and differentiate the P export dynamics of the various forms and inputs of P. To identify the phosphorus sources and evaluate their change in response to environmental policies, we developed a simple and loaded-oriented model (POPEYE - PhOsPhorus, Evaluation of the efficiencY of Environmental policy measures) that computes retention, settling and re-suspension rates of fine and coarse P fractions and their relation to P concentration of bed sediments. The model is calibrated to a long-term database (25 years), and describes the weekly water and chemical fluxes of a tributary of Lac Léman (Lake Geneva, Venoge river watershed, 240 km2). It adequately predicts observed values of fine and particulate phosphorus and reflects the gradual decrease of point and diffuse inputs over the studied period due to agricultural and sewage treatment policies implemented for the control of lake pollution.

  19. ac bidirectional motor controller

    NASA Technical Reports Server (NTRS)

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  20. Factors Associated With Long-Term Weight Loss Following Bariatric Surgery Using 2 Methods for Repeated Measures Analysis.

    PubMed

    Baldridge, Abigail S; Pacheco, Jennifer A; Aufox, Sharon A; Kim, Kwang-Youn A; Silverstein, J C; Denham, W; Hungness, E; Smith, Maureen E; Allen, Norrina B; Greenland, Philip; Rasmussen-Torvik, Laura J

    2015-08-01

    We used electronic health record data from 162 patients enrolled in the NUgene Project (2002-2013) to determine demographic factors associated with long-term (from 1 to up to 9.5 (mean = 5.6) years) weight loss following Roux-en-Y gastric bypass surgery. Ninety-nine (61.1%) patients self-reported white, and 63 (38.9%) self-reported black, mixed, or missing race. The average percent weight loss was -33.4% (standard deviation, 9.3) at 1 year after surgery and -30.7% (standard deviation, 12.5) at the last follow-up point. We used linear mixed and semiparametric trajectory models to test the association of surgical and demographic factors (height, surgery age, surgery weight, surgery body mass index, marital status, sex, educational level, site, International Classification of Diseases code, Current Procedural Terminology code, Hispanic ethnicity, and self-reported race) with long-term percent weight loss and pattern of weight loss. We found that black, mixed, and missing races (combined) in comparison with white race were associated with a decreased percent weight loss of -4.31% (95% confidence interval: -7.30, -1.32) and were less likely to have higher and sustained percent weight loss (P = 0.04). We also found that less obese patients were less likely to have higher and sustained percent weight loss (P = 0.01). These findings may be helpful to patients in setting expectations after weight loss surgery. PMID:26093003

  1. Artificial Neural Networks-Based Software for Measuring Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters.

    PubMed

    Liu, Zhijian; Liu, Kejun; Li, Hao; Zhang, Xinyu; Jin, Guangya; Cheng, Kewei

    2015-01-01

    Measurements of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, conventional measurement requires expensive detection devices and undergoes a series of complicated procedures. To simplify the measurement and reduce the cost, software based on artificial neural networks for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters was developed. Using multilayer feed-forward neural networks with back-propagation algorithm, we developed and tested our program on the basis of 915 measured samples of water-in-glass evacuated tube solar water heaters. This artificial neural networks-based software program automatically obtained accurate heat collection rate and heat loss coefficient using simply "portable test instruments" acquired parameters, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, angle between tubes and ground and final temperature. Our results show that this software (on both personal computer and Android platforms) is efficient and convenient to predict the heat collection rate and heat loss coefficient due to it slow root mean square errors in prediction. The software now can be downloaded from http://t.cn/RLPKF08. PMID:26624613

  2. AC Conductivity and Dielectric Relaxation Behavior of Sb2S3 Bulk Material

    NASA Astrophysics Data System (ADS)

    Abd El-Rahman, K. F.; Darwish, A. A. A.; Qashou, Saleem I.; Hanafy, T. A.

    2016-04-01

    The Sb2S3 bulk material was used for next-generation anode for lithium-ion batteries. Alternative current (AC) conductivity, dielectric properties and electric modulus of Sb2S3 have been investigated. The measurements were carried out in the frequency range from 40 Hz to 5 MHz and temperature range from 293 K to 453 K. The direct current (DC) conductivity, σ DC, shows an activated behavior and the calculated activation energy is 0.50 eV. The AC conductivity, σ AC, was found to increase with the increase of temperature and frequency. The conduction mechanism of σ AC was controlled by the correlated barrier hopping model. The behavior of the dielectric constant, ɛ', and dielectric loss index, ɛ'', reveal that the polarization process of Sb2S3 is dipolar in nature. The behavior of both ɛ' and ɛ'' reveals that bulk Sb2S3 has no ferroelectric or piezoelectric phase transition. The dielectric modulus, M, gives a simple method for evaluating the activation energy of the dielectric relaxation. The calculated activation energy from M is 0.045 eV.

  3. AC Conductivity and Dielectric Relaxation Behavior of Sb2S3 Bulk Material

    NASA Astrophysics Data System (ADS)

    Abd El-Rahman, K. F.; Darwish, A. A. A.; Qashou, Saleem I.; Hanafy, T. A.

    2016-07-01

    The Sb2S3 bulk material was used for next-generation anode for lithium-ion batteries. Alternative current (AC) conductivity, dielectric properties and electric modulus of Sb2S3 have been investigated. The measurements were carried out in the frequency range from 40 Hz to 5 MHz and temperature range from 293 K to 453 K. The direct current (DC) conductivity, σ DC, shows an activated behavior and the calculated activation energy is 0.50 eV. The AC conductivity, σ AC, was found to increase with the increase of temperature and frequency. The conduction mechanism of σ AC was controlled by the correlated barrier hopping model. The behavior of the dielectric constant, ɛ', and dielectric loss index, ɛ'', reveal that the polarization process of Sb2S3 is dipolar in nature. The behavior of both ɛ' and ɛ'' reveals that bulk Sb2S3 has no ferroelectric or piezoelectric phase transition. The dielectric modulus, M, gives a simple method for evaluating the activation energy of the dielectric relaxation. The calculated activation energy from M is 0.045 eV.

  4. AC/RF Superconductivity

    SciTech Connect

    Ciovati, Gianluigi

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  5. AC solar cell

    SciTech Connect

    Schutten, H.P.; Benjamin, J.A.; Lade, R.W.

    1986-03-18

    An AC solar cell is described comprising: a pair of PN junction type solar cells connected in antiparallel between a pair of main terminals; and means for electrically directing light alternatingly without mechanical movement on the PN junctions to generate an alternating potential across the main terminals.

  6. AC 67 Launch Video

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Live footage of the Unmanned Atlas Centaur (AC) 67 launch is presented on March 26, 1987 at the WESH television station in Florida. Lightning is shown after 49 seconds into the flight. The vehicle is totally destroyed due to a cloud-to-ground lightning flash.

  7. Artificial Neural Networks-Based Software for Measuring Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters

    PubMed Central

    Liu, Zhijian; Liu, Kejun; Li, Hao; Zhang, Xinyu; Jin, Guangya; Cheng, Kewei

    2015-01-01

    Measurements of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, conventional measurement requires expensive detection devices and undergoes a series of complicated procedures. To simplify the measurement and reduce the cost, software based on artificial neural networks for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters was developed. Using multilayer feed-forward neural networks with back-propagation algorithm, we developed and tested our program on the basis of 915measuredsamples of water-in-glass evacuated tube solar water heaters. This artificial neural networks-based software program automatically obtained accurate heat collection rateand heat loss coefficient using simply "portable test instruments" acquired parameters, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, angle between tubes and ground and final temperature. Our results show that this software (on both personal computer and Android platforms) is efficient and convenient to predict the heat collection rate and heat loss coefficient due to it slow root mean square errors in prediction. The software now can be downloaded from http://t.cn/RLPKF08. PMID:26624613

  8. The impact of stability corrections for flux-gradient relationships on measurements of the volatile loss of pesticide from agricultural ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatilization represents the primary pathway loss for many pesticides. One common method for measuring pesticide volatilization is the aerodynamic flux-gradient method. Using this method, the pesticide flux is estimated as the product of the vertical pesticide concentration gradient and a turbulen...

  9. A Fe-C coated long-period fiber grating sensor for corrosion-induced mass loss measurement.

    PubMed

    Chen, Yizheng; Tang, Fujian; Bao, Yi; Tang, Yan; Chen, Genda

    2016-05-15

    This Letter reports a Fe-C coated long period fiber gratings sensor with a grating period of 387±0.1  μm for corrosion monitoring of low carbon steel in a 3.5 wt. % NaCl solution. An LPFG sensor was first deposited with a 0.8 μm thick layer of silver (Ag) and then electroplated with a 20 μm thick Fe-C coating. The chemical composition of the Fe-C coating was designed to include the main elements of low carbon steel. The resonant wavelength of the coated sensor was correlated with the mass loss of steel over time. Test results indicated a corrosion sensitivity of 0.0423 nm per 1% mass loss up to 80% Fe-C mass loss and 0.576 nm per 1% mass loss between 80% and 95% Fe-C mass loss. The corrosion sensitivity of such a Fe-C coated LPFG sensor was a trade-off for the service life of the sensor, both depending on thicknesses of the inner silver layer and the outer Fe-C coating. PMID:27176989

  10. Geometrical effect on the measurement of stopping power: Angle-dependent energy loss of 5 MeV protons in Au

    NASA Astrophysics Data System (ADS)

    Ishiwari, R.; Shiomi-Tsuda, N.; Sakamoto, N.; Ogawa, H.

    1990-03-01

    The geometrical effect on the measurement of stopping power - the angle-dependent energy loss of 5 MeV protons in Au - has been measured using a very homogeneous Au target. The inhomogeneity of the target thickness has been investigated by electron microscopy and by comparing the observed straggling of the energy loss with the predictions of the straggling theories. The inhomogeneity of the target thickness was estimated to be at most 3.27% of the average thickness. The effect of the target inhomogeneity on the angular dependence of the energy loss has been investigated by calculating the average target thickness as a function of the emergence angle. After subtracting the effect of the target inhomogeneity, the energy loss increases about 1.55% as the emergence angle increases from 0.64° to 3.82°. We conclude that this increase of the energy loss as a function of the emergence angle is a manifestation of an impact parameter dependence of electronic stopping.

  11. Variability of ozone loss during Arctic winter (1991 to 2000) estimated from UARS Microwave Limb Sounder measurement

    NASA Technical Reports Server (NTRS)

    Manney, G.; Froidevaux, F.; Santee, M. L.; Livesey, N. J.; Sabutis, J. L.; Waters, J. W.

    2002-01-01

    A comprehensive analysis of version 5 Upper Atmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS) ozone data using a Lagrangian Transport (LT) model provides estimates of chemical ozone depletion for the 1991-1992 through 1997-1998 Arctic winters. These new estimates give a consistent, three-dimensional picture of ozone loss during seven Arctic winters; previous Arctic ozone loss estimates from MLS were based on various earlier data versions and were done only for late winter and only for a subset of the years observed by MLS. We find large interannual variability in the amount, timing, and patterns of ozone depletion and in the degree to which chemical loss is masked by dynamical processes.

  12. dc and ac magnetic properties of thin-walled Nb cylinders with and without a row of antidots.

    PubMed

    Tsindlekht, M I; Genkin, V M; Felner, I; Zeides, F; Katz, N; Gazi, Š; Chromik, Š; Dobrovolskiy, O V; Sachser, R; Huth, M

    2016-06-01

    dc and ac magnetic properties of two thin-walled superconducting Nb cylinders with a rectangular cross-section are reported. Magnetization curves and the ac response were studied on as-prepared and patterned samples in magnetic fields parallel to the cylinder axis. A row of micron-sized antidots (holes) was made in the film along the cylinder axis. Avalanche-like jumps of the magnetization are observed for both samples at low temperatures for magnetic fields not only above H c1, but in fields lower than H c1 in the vortex-free region. The positions of the jumps are not reproducible and they change from one experiment to another, resembling vortex lattice instabilities usually observed for magnetic fields larger than H c1. At temperatures above [Formula: see text] and [Formula: see text] the magnetization curves become smooth for the patterned and the as-prepared samples, respectively. The magnetization curve of a reference planar Nb film in the parallel field geometry does not exhibit jumps in the entire range of accessible temperatures. The ac response was measured in constant and swept dc magnetic field modes. Experiment shows that ac losses at low magnetic fields in a swept field mode are smaller for the patterned sample. For both samples the shapes of the field dependences of losses and the amplitude of the third harmonic are the same in constant and swept field near H c3. This similarity does not exist at low fields in a swept mode. PMID:27143621

  13. Turnover and losses of phosphorus in Swedish agricultural soils: long-term changes, leaching trends, and mitigation measures.

    PubMed

    Bergström, Lars; Kirchmann, Holger; Djodjic, Faruk; Kyllmar, Katarina; Ulén, Barbro; Liu, Jian; Andersson, Helena; Aronsson, Helena; Börjesson, Gunnar; Kynkäänniemi, Pia; Svanbäck, Annika; Villa, Ana

    2015-03-01

    Transport of phosphorus (P) from agricultural fields to water bodies deteriorates water quality and causes eutrophication. To reduce P losses and optimize P use efficiency by crops, better knowledge is needed of P turnover in soil and the efficiency of best management practices (BMPs). In this review, we examined these issues using results from 10 Swedish long-term soil fertility trials and various studies on subsurface losses of P. The fertility trials are more than 50 years old and consist of two cropping systems with farmyard manure and mineral fertilizer. One major finding was that replacement of P removed by crops with fertilizer P was not sufficient to maintain soil P concentrations, determined with acid ammonium lactate extraction. The BMPs for reducing P leaching losses reviewed here included catch crops, constructed wetlands, structure liming of clay soils, and various manure application strategies. None of the eight catch crops tested reduced P leaching significantly, whereas total P loads were reduced by 36% by wetland installation, by 39 to 55% by structure liming (tested at two sites), and by 50% by incorporation of pig slurry into a clay soil instead of surface application. Trend analysis of P monitoring data since the 1980s for a number of small Swedish catchments in which various BMPs have been implemented showed no clear pattern, and both upward and downward trends were observed. However, other factors, such as weather conditions and soil type, have profound effects on P losses, which can mask the effects of BMPs. PMID:26023970

  14. Hearing loss in space

    NASA Technical Reports Server (NTRS)

    Buckey, J. C. Jr; Musiek, F. E.; Kline-Schoder, R.; Clark, J. C.; Hart, S.; Havelka, J.

    2001-01-01

    BACKGROUND: Temporary and, in some cases, permanent hearing loss has been documented after long-duration spaceflights. METHODS: We examined all existing published data on hearing loss after space missions to characterize the losses. RESULTS: Data from Russian missions suggest that the hearing loss, when it occurs, affects mainly mid to high frequencies and that using hearing protection often might prevent the loss. Several significant questions remain about hearing loss in space. While the hearing loss has been presumed to be noise-induced, no clear link has been established between noise exposure and hearing loss during spaceflight. In one documented case of temporary hearing loss from the Shuttle-Mir program, the pattern of loss was atypical for a noise-induced loss. Continuous noise levels that have been measured on the Mir and previous space stations, while above engineering standards, are not at levels usually associated with hearing loss in ground-based studies (which have usually been limited to 8-10 h exposure periods). Attempts to measure hearing in space using threshold-based audiograms have been unsuccessful in both the American and Russian programs due to noise interference with the measurements. CONCLUSIONS: The existing data highlight the need for reliable monitoring of both hearing and noise in long-duration spaceflight.

  15. AC power systems handbook

    SciTech Connect

    Whitaker, J.

    1991-01-01

    Transient disturbances are what headaches are made of. Whatever you call them-spikes, surges, are power bumps-they can take your equipment down and leave you with a complicated and expensive repair job. Protection against transient disturbances is a science that demands attention to detail. This book explains how the power distribution system works, what can go wrong with it, and how to protect a facility against abnormalities. system grounding and shielding are covered in detail. Each major method of transient protection is analyzed and its relative merits discussed. The book provides a complete look at the critical elements of the ac power system. Provides a complete look at the ac power system from generation to consumption. Discusses the mechanisms that produce transient disturbances and how to protect against them. Presents diagrams to facilitate system design. Covers new areas, such as the extent of the transient disturbance problem, transient protection options, and stand-by power systems.

  16. Pb loss in Pb(Zr,Ti)O3 ceramics observed by in situ ionic conductivity measurements

    NASA Astrophysics Data System (ADS)

    Donnelly, Niall J.; Randall, Clive A.

    2011-05-01

    Analysis of the impedance spectra of Nb-doped Pb(Zr,Ti)O3 (PZT) embedded capacitors revealed that the ionic conductivity increased monotonically during annealing at 700 °C. Furthermore, the rate of increase was lowered by a reduction in the ambient pO2. The results could be explained by a model in which oxygen vacancies are generated as a consequence of Pb evaporation from the PZT. At 700 °C, this process is most likely limited by surface kinetics rather than Pb bulk diffusion. It was shown that the Pb loss could be completely recovered by annealing in a high activity Pb source with a commensurate reduction in oxygen vacancy concentration. The electronic conductivity was predominantly p-type and was relatively unaffected by the Pb loss throughout the course of the experiment.

  17. First quasi-Lagrangian in situ measurements of Antarctic Polar springtime ozone: observed ozone loss rates from the Concordiasi long-duration balloon campaign

    NASA Astrophysics Data System (ADS)

    Schofield, R.; Avallone, L. M.; Kalnajs, L. E.; Hertzog, A.; Wohltmann, I.; Rex, M.

    2015-03-01

    We present ozone measurements made using state-of-the-art ultraviolet photometers onboard three long-duration stratospheric balloons launched as part of the Concordiasi campaign in austral spring 2010. Ozone loss rates calculated by matching air parcels sampled at different times and places during the polar spring are in agreement with rates previously derived from ozonesonde measurements, for the vortex average, ranging between 2 and 7 ppbv per sunlit hour or between 25 and 110 ppbv per day. However, the geographical coverage of these long-duration stratospheric balloon platforms provides new insights into the temporal and spatial patterns of ozone loss over Antarctica. Very large ozone loss rates of up to 230 ppbv per day (16 ppbv per sunlit hour) are observed for air masses that are downwind of the Antarctic Peninsula and/or over the East Antarctic region. The ozone loss rate maximum downstream of the Antarctic Peninsula region is consistent with high PSC occurrence from CALIPSO and large ClO abundances from MLS satellite observations for 12-22 September 2010, and with a chemical box model simulation using JPL 2011 kinetics with full chlorine activation.

  18. Effectiveness Of Miraba an Indigenous Soil and Water Conservation Measures On Reducing Runoff And Soil Loss In Arable Land Of Western Usambara Mountains

    NASA Astrophysics Data System (ADS)

    Msita, H. B.; Kimaro, D. N.; Mtakwa, P. W.; Msanya, B. M.; Dondyene, S.; Poesen, J.; Deckers, J.

    2012-04-01

    Soil erosion by water is rampant mainly in mountainous areas of Tanzania leading to environmental hazards, low land productivity, low income and increased poverty. Despite the severity of the soil erosion problem, there is not much quantitative data on the erosion effects and effectiveness of indigenous soil and water conservation (SWC) measures. The consequence is that indigenous knowledge in SWC planning is ignored. The on-farm field experiment was conducted for three years in Migambo village, Lushoto district in Tanzania, to determine the effectiveness of improved Miraba (IM) an indigenous soil erosion control measure on reducing runoff and soil loss. Management practices were tested viz: control that is without any soil conservation measure (C), Miraba alone (M), Miraba with farmyard manure and mulching (MFM) replicated three times in CRD setting. Maize (Zea mays) and beans (Phaseolus vulgaris) were used as test crops, due to their importance as food crops and the high erosion rates on fields with these crops. The crops were planted in rotation, maize and beans in short and long rains respectively. Gerlach troughs and runoff plots were used to evaluate the physical effectiveness. Results show significant effects of IM against control on crop yields, soil loss, surface runoff and moisture retention. MFM is the most effective measure in reducing soil and water losses followed by MF and M. The results further showed that these management practices can be implemented to reduce soil erosion and nutrient losses in the study area and areas with similar ecological setting. To facilitate adoption of these practices further research works is recommended for identifying economically feasible indigenous SWC measures under different biophysical and socio-economic conditions.

  19. Quenching characteristics of a.c. superconducting coils

    NASA Astrophysics Data System (ADS)

    Akita, S.; Kasahara, H.; Torii, S.

    Quenching characteristics of two superconducting coils for a.c. use are investigated at different frequencies. One is impregnated with epoxy resin and the other is not. Both coils have experienced over 40 quenches in a.c. and d.c. The impregnated coil shows steady quenching currents for a.c. and the values are nearly the same as for d.c. On the other hand, quenching currents for a.c. in the non-impregnated coil are almost 80% of the trained-up d.c. quenching current and are scattered. Furthermore, the relationship between quenching currents and the estimated a.c. losses of the superconducting cable at the highest magnetic field point is investigated. According to the results of this investigation, the cause of quench in the impregnated coil is assumed to be the temperature rise of the winding due to a.c. losses, while the cause in the non-impregnated coil might be wire motion.

  20. Magnetic core test stand for energy loss and permeability measurements at a high constant magnetization rate and test results for nanocrystalline and ferrite materials.

    PubMed

    Burdt, Russell; Curry, Randy D

    2008-09-01

    A test stand was developed to measure the energy losses and unsaturated permeability of toroidal magnetic cores, relevant to applications of magnetic switching requiring a constant magnetization rate of the order of 1-10 T/micros. These applications in pulsed power include linear induction accelerators, pulse transformers, and discharge switches. The test stand consists of a coaxial transmission line pulse charged up to 100 kV that is discharged into a magnetic core load. Suitable diagnostics measure the voltage across and the current through a winding on the magnetic core load, from which the energy losses and unsaturated permeability are calculated. The development of the test stand is discussed, and test results for ferrite CN20 and the nanocrystalline material Finemet FT-1HS are compared to demonstrate the unique properties of a nanocrystalline material. The experimental data are compared with published data in a similar parameter space to demonstrate the efficacy of the experimental methods. PMID:19044442

  1. Primordial argon isotope fractionation in the atmosphere of Mars measured by the SAM instrument on Curiosity and implications for atmospheric loss

    PubMed Central

    Atreya, Sushil K; Trainer, Melissa G; Franz, Heather B; Wong, Michael H; Manning, Heidi L K; Malespin, Charles A; Mahaffy, Paul R; Conrad, Pamela G; Brunner, Anna E; Leshin, Laurie A; Jones, John H; Webster, Christopher R; Owen, Tobias C; Pepin, Robert O; Navarro-González, R

    2013-01-01

    [1] The quadrupole mass spectrometer of the Sample Analysis at Mars (SAM) instrument on Curiosity rover has made the first high-precision measurement of the nonradiogenic argon isotope ratio in the atmosphere of Mars. The resulting value of 36Ar/38Ar = 4.2 ± 0.1 is highly significant for it provides excellent evidence that “Mars” meteorites are indeed of Martian origin, and it points to a significant loss of argon of at least 50% and perhaps as high as 85–95% from the atmosphere of Mars in the past 4 billion years. Taken together with the isotopic fractionations in N, C, H, and O measured by SAM, these results imply a substantial loss of atmosphere from Mars in the posthydrodynamic escape phase. PMID:25821261

  2. A novel experimental setup for energy loss and charge state measurements in dense moderately coupled plasma using laser-heated hohlraum targets

    NASA Astrophysics Data System (ADS)

    Ortner, A.; Schumacher, D.; Cayzac, W.; Frank, A.; Basko, M. M.; Bedacht, S.; Blazevic, A.; Faik, S.; Kraus, D.; Rienecker, T.; Schaumann, G.; Tauschwitz, An.; Wagner, F.; Roth, M.

    2016-03-01

    We report on a new experimental setup for ion energy loss measurements in dense moderately coupled plasma which has recently been developed and tested at GSI Darmstadt. A partially ionized, moderately coupled carbon plasma (ne ≤ 0.8• 1022 cm-3, Te = 15 eV, z = 2.5, Γ = 0.5) is generated by volumetrical heating of two thin carbon foils with soft X-rays. This plasma is then probed by a bunched heavy ion beam. For that purpose, a special double gold hohlraum target of sub-millimeter size has been developed which efficiently converts intense laser light into thermal radiation and guarantees a gold-free interaction path for the ion beam traversing the carbon plasma. This setup allows to do precise energy loss measurements in non-ideal plasma at the level of 10 percent solid-state density.

  3. Development of a nano-tesla magnetic field shielded chamber and highly precise AC-susceptibility measurement coil at μK temperatures

    NASA Astrophysics Data System (ADS)

    Kumar, Anil; Prakash, Om; Ramakrishanan, S.

    2014-04-01

    A special sample measurement chamber has been developed to perform experiments at ultralow temperatures and ultralow magnetic field. A high permeability material known as cryoperm 10 and Pb is used to shield the measurement space consisting of the signal detecting set-up and the sample. The detecting setup consists of a very sensitive susceptibility coil wound on OFHC Cu bobbin.

  4. ACS Algorithm in Discrete Ordinates for Pressure Vessel Dosimetry

    NASA Astrophysics Data System (ADS)

    Walters, William; Haghighat, Alireza

    2016-02-01

    The Adaptive Collision Source (ACS) method can solve the Linear Boltzmann Equation (LBE) more efficiently by adaptation of the angular quadrature order. This is similar to, and essentially an extension of, the first collision source method. Previously, the ACS methodology has been implemented into the TITAN discrete ordinates code, and has shown speedups of 2-4 on a simple test problem, with very little loss of accuracy (within a provided adaptive tolerance). This work examines the use of the ACS method for a more realistic problem: pressure vessel dosimetry with the VENUS-2 MOX-fuelled reactor dosimetry benchmark. The ACS method proved to be able to obtain accurate results while being approximately twice as efficient as using a constant quadrature in a standard source iteration scheme.

  5. High-Frequency ac Power-Distribution System

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.; Mildice, James

    1987-01-01

    Loads managed automatically under cycle-by-cycle control. 440-V rms, 20-kHz ac power system developed. System flexible, versatile, and "transparent" to user equipment, while maintaining high efficiency and low weight. Electrical source, from dc to 2,200-Hz ac converted to 440-V rms, 20-kHz, single-phase ac. Power distributed through low-inductance cables. Output power either dc or variable ac. Energy transferred per cycle reduced by factor of 50. Number of parts reduced by factor of about 5 and power loss reduced by two-thirds. Factors result in increased reliability and reduced costs. Used in any power-distribution system requiring high efficiency, high reliability, low weight, and flexibility to handle variety of sources and loads.

  6. Hair Loss

    MedlinePlus

    ... may cause hair loss in women. If your hair loss has occurred gradually with advancing age, FOLLICULAR DEGENERATION may be the cause. Post-pregnancy hormone changes usually reverse themselves without any treatment. While follicular degeneration cannot ...

  7. Modelling ac ripple currents in HTS coated conductors

    NASA Astrophysics Data System (ADS)

    Xu, Zhihan; Grilli, Francesco

    2015-10-01

    Dc transmission using high temperature superconducting (HTS) coated conductors (CCs) offers a promising solution to the globally growing demand for effective, reliable and economic transmission of green energy up to the gigawatt level over very long distances. The credible estimation of the losses and thereby the heat dissipation involved, where ac ripples (introduced in rectification/ac-dc conversion) are viewed as a potential source of notable contribution, is highly essential for the rational design of practical HTS dc transmission cables and corresponding cryogenic systems to fulfil this demand. Here we report a targeted modelling study into the ac losses in a HTS CC subject to dc and ac ripple currents simultaneously, by solving Maxwell’s equations using the finite element method (FEM) in the commercial software package COMSOL. It is observed that the instantaneous loss exhibits only one peak per cycle in the HTS CC subject to sinusoidal ripples, given that the amplitude of the ac ripples is smaller than approximately 20% of that of the dc current. This is a distinct contrast to the usual observation of two peaks per cycle in a HTS CC subject to ac currents only. The unique mechanism is also revealed, which is directly associated with the finding that, around any local minima of the applied ac ripples, the critical state of -J c is never reached at the edges of the HTS CC, as it should be according to the Bean model. When running further into the longer term, it is discovered that the ac ripple loss of the HTS CC in full-wave rectification decays monotonically, at a speed which is found to be insensitive to the frequency of the applied ripples within our targeted situations, to a relatively low level of approximately 1.38 × 10-4 W m-1 in around 1.7 s. Comparison between this level and other typical loss contributions in a HTS dc cable implies that ac ripple currents in HTS CCs should only be considered as a minor source of dissipation in superconducting dc

  8. On the lack of correlation between self-report and urine loss measured with standing provocation test in older stress-incontinent women.

    PubMed

    Miller, J M; Ashton-Miller, J A; Carchidi, L T; DeLancey, J O

    1999-03-01

    This study examined the association between the measured amount of urine lost during a standardized series of coughs in clinic (paper towel test) and questionnaire estimates of stress-related urine loss in 51 older women with mild to moderate urinary incontinence. It also examined the relationship between these questionnaire estimates and a 6-day urinary diary self-report of incontinence frequency and voiding episodes. Pearson's correlation coefficient and percent agreement were used to analyze the relationship between the variables. No significant correlations were found between the paper towel test results and questionnaire items reporting volume of urine loss. The relationship between urinary diary results and questionnaire items regarding the number of incontinence occurrences was weak but significant (r = 0.33, p = 0.045), with agreement in 53% of cases. Agreement was achieved in 68% of cases for number of voids per day recorded by urinary diary and reported by questionnaire (r = 0.65, p = 0.000). This study has quantified a weak correlation between objective and subjective measures of urine loss. These weak correlations could arise from either methodologic limitations in quantifying incontinence or the degree to which differences arise because different phenomena are being measured. PMID:10100129

  9. High Temperature Microwave Dielectric Properties of JSC-1AC Lunar Simulant

    NASA Technical Reports Server (NTRS)

    Allan, Shawn M.; Merritt, Brandon J.; Griffin, Brittany F.; Hintze, Paul E.; Shulman, Holly S.

    2011-01-01

    Microwave heating has many potential lunar applications including sintering regolith for lunar surface stabilization and heating regolith for various oxygen production reactors. The microwave properties of lunar simulants must be understood so this technology can be applied to lunar operations. Dielectric properties at microwave frequencies for a common lunar simulant, JSC-1AC, were measured up to 1100 C, which is approximately the melting point. The experimentally determined dielectric properties included real and imaginary permittivity (epsilon', epsilon"), loss tangent (tan delta), and half-power depth, the di stance at which a material absorbs 50% of incident microwave energy. Measurements at 2.45 GHz revealed tan delta of JSC-1A increases from 0.02 at 25 C to 0.31 at 110 C. The corresponding half-power depth decreases from a peak of 286 mm at 110 C, to 13 mm at 1100 C. These data indicate that JSC-1AC becomes more absorbing, and thus a better microwave heater as temperature increases. A half-power depth maximum at 100-200 C presents a barrier to direct microwave heating at low temperatures. Microwave heating experiments confirm the sluggish heating effect of weak absorption below 200 C, and increasingly strong absorption above 200 C, leading to rapid heating and melting of JSC-1AC.

  10. Protection of superconducting AC windings

    SciTech Connect

    Verhaege, T.; Agnoux, C.; Tavergnier, J.P. ); Lacaze, A. ); Collet, M. )

    1992-01-01

    Recent progresses on multifilamentary wires open new prospects of 50-60 Hz applications for superconductivity. The problem of AC windings protection is more critical than that of DC windings, because of high current densities, and of high matrix resistivity: one should not allow the quenched wire to carry it nominal current for longer than a few milliseconds, otherwise permanent damage could occur. After a quench initiation, the protection system therefore has to switch off or drastically reduce the current very rapidly. In this paper, the authors propose various schemes, applicable when the conductor is made of several wires: active protection involves an ultra-rapid quench detection. It is based on the measurement of the current passing through the central resistive wire, and/or of unbalanced currents in the different superconducting wires. About 20 milliseconds after detection, a fast circuit-breaker switched off the current. A complementary passive protection is provided by the resistance developing during normal phase propagation.

  11. Comparison of three measuring systems at high frequency for non oriented silicon steels: influence of the rolling direction on magnetic losses and B(H) curve

    NASA Astrophysics Data System (ADS)

    Hamrit, Oussama; De la Barrière, Olivier; LoBue, Martino; Lécrivain, Michel; Mazaleyrat, Frédéric

    2015-09-01

    Loss data available in literature on laminated magnetic materials excited by alternating induction are often limited to rather low frequencies, (e.g., below 1 kHz). This is far below the frequencies experienced by materials used in high speed electrical machines. In this work, an appropriate measurement setup is used to evaluate losses in 0.35 mm thick iron silicon NO lamination up to an alternating peak induction of 1 T at a frequency of 10 kHz. In these conditions the capacitive effects are relevant on the B-coil and the H-coil when standard Epstein frame is used and might affect the measurements. A method to avoid this problem is proposed, based on a comparison between three characterization systems: a new single sheet tester that we use as a reference system, a conventional Epstein frame with 700 turns and a second Epstein frame with 200 turns dedicated to high-frequency. In the first part of the study we present an assessment of the limits of each system. An empirical correction factor is introduced to obtain the true loss value from measurement using the Epstein frame (700 turns from DC to 400 Hz and 200 turns from 400 Hz to 10 kHz). Finally, a comparison between two non-oriented FeSi of different quality and different thicknesses (0.35 mm and 0.2 mm) is presented in a wide range of frequencies (from DC to 10 kHz). Based on the loss separation theory, the skin effect on the two samples has been highlighted. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2014)", edited by Adel Razek

  12. Equivalent Electrical Circuit Representations of AC Quantized Hall Resistance Standards

    PubMed Central

    Cage, M. E.; Jeffery, A.; Matthews, J.

    1999-01-01

    We use equivalent electrical circuits to analyze the effects of large parasitic impedances existing in all sample probes on four-terminal-pair measurements of the ac quantized Hall resistance RH. The circuit components include the externally measurable parasitic capacitances, inductances, lead resistances, and leakage resistances of ac quantized Hall resistance standards, as well as components that represent the electrical characteristics of the quantum Hall effect device (QHE). Two kinds of electrical circuit connections to the QHE are described and considered: single-series “offset” and quadruple-series. (We eliminated other connections in earlier analyses because they did not provide the desired accuracy with all sample probe leads attached at the device.) Exact, but complicated, algebraic equations are derived for the currents and measured quantized Hall voltages for these two circuits. Only the quadruple-series connection circuit meets our desired goal of measuring RH for both ac and dc currents with a one-standard-deviation uncertainty of 10−8 RH or less during the same cool-down with all leads attached at the device. The single-series “offset” connection circuit meets our other desired goal of also measuring the longitudinal resistance Rx for both ac and dc currents during that same cool-down. We will use these predictions to apply small measurable corrections, and uncertainties of the corrections, to ac measurements of RH in order to realize an intrinsic ac quantized Hall resistance standard of 10−8 RH uncertainty or less.

  13. Identification of /sup 233/Ac

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1983-09-01

    We report in this paper identification of the new isotope /sup 233/Ac. Uranium targets were irradiated with 28 GeV protons; after rapid retrieval of the target and separation of actinium from thorium, /sup 233/Ac was allowed to decay into the known /sup 233/Th daughter. Exhaustive chemical purification was employed to permit the identification of /sup 233/Th via its characteristic ..gamma.. radiations. The half-life derived for /sup 233/Ac from several experiments is 2.3 +- 0.3 min. The production cross section for /sup 233/Ac is 100 ..mu..b.

  14. Measurement of energy loss profiles during short duration sliding contacts: a computer-compatible instrument based on the British Pendulum Skid Tester

    NASA Astrophysics Data System (ADS)

    Andrew, Keith R.; Cunningham, Alex

    1998-09-01

    This paper describes a structurally modified British Pendulum Skid Tester fitted with an optical encoder (2500 pulses per revolution), pulse timing electronics (0957-0233/9/9/028/img1 resolution) and a computer interface (IBM compatible PIO card). A spring-loaded rectangular slider attached to the foot of the pendulum is driven across a horizontal surface at speeds of up to 0957-0233/9/9/028/img2. By measuring changes in the angular velocity of the pendulum, it is possible to calculate the loss of energy due to friction with 1 mm linear resolution. Values for the path-averaged coefficient of friction for thermoplastic and elastomer sliders can be determined with a precision of around 1%, enabling highly reproducible studies of the influence of slider wear and surface condition on friction losses to be carried out. Energy loss profiles measured during the passage of the slider over the surface can reveal variations in surface roughness as well as details of the slider/substrate interaction. Force profiles for natural rubber sliders travelling over smooth surfaces at speeds in excess of 0957-0233/9/9/028/img3 show well-defined stick-slip oscillations in the force of sliding friction.

  15. Superconductor films with improved flux pinning and reduced AC losses

    DOEpatents

    Goyal, Amit

    2011-04-05

    The present invention relates to a method for producing a defect-containing superconducting film, the method comprising (a) depositing a phase-separable layer epitaxially onto a biaxially-textured substrate, wherein the phase-separable layer includes at least two phase-separable components; (b) achieving nanoscale phase separation of the phase-separable layer such that a phase-separated layer including at least two phase-separated components is produced; and (c) depositing a superconducting film epitaxially onto said phase-separated components of the phase-separated layer such that nanoscale features of the phase-separated layer are propagated into the superconducting film.

  16. Procedures used in the calibration of AC calibrators

    SciTech Connect

    Salazar, M.T.

    1991-02-01

    This report describes an automatic calibration system used in the calibration of all precision AC calibrators. The system includes an AC-DC Transfer Standard, a DC Voltage Standard, and a high-resolution digital multimeter, with an IBM-XT Personal Computer for data acquisition and analysis. Specialized instrumentation and measurement techniques make it possible to achieve high accuracy measurements with repeatability. 5 refs., 3 figs.

  17. Measuring Black Carbon Concentrations in Liquid Samples Using the Single Particle Soot Photometer: Addressing Black Carbon Losses During Sample Storage and Nebulization

    NASA Astrophysics Data System (ADS)

    Menking, J. A.; Kaspari, S.; Jenkins, M.

    2011-12-01

    Black Carbon (BC), an aerosol created from the incomplete combustion of fossil and bio-fuels, is the second largest contributor to global warming next to CO2. BC deposited on snow and ice reduces the surface albedo, accelerating seasonal snowmelt and glacier retreat and influencing the regional water cycle and climate (Hansen and Nazarenko, 2004). BC emissions and its post-depositional spatial distribution in snow and ice are a large uncertainty in climate change analyses, thus measurements of global BC concentrations in liquid samples of snow and ice are desirable. The Single Particle Soot Photometer (SP2) is a relatively new method for measuring BC concentrations in liquid samples with promising advantages over other commonly used methods, namely that measurements require smaller sample volumes and are not affected by the presence of other absorbing particles. Despite potential advantages over traditional methods, total BC in liquid samples cannot be quantified because of methodological uncertainties. Preliminary tests show BC losses related to (1) nebulization and (2) changes to the sample during storage. BC in storage may adhere to the vial walls, resulting in BC losses. Particles containing BC may also agglomerate to form large particles with sizes outside of the SP2 detection range (80-650nm). Further losses are indicated in a comparison of polydisperse Aquadag (BC standard) particle size distributions between the ultrasonic nebulizer and a collision-type atomizer, which shows a loss of particles > ~500nm associated with the Cetac U-5000AT+ ultrasonic nebulizer. Larger particles may not be nebulized because of inefficiencies related to the ultrasonic transducer plate, and/or highly charged particles may adhere to the glass within the nebulizer, also resulting in BC losses. The purpose of this study was to determine the methods of storage and nebulization that maximize the amount of BC delivered to the SP2 inlet. Storage and sample parameters tested include

  18. Magnetic flux penetration into twisted multifilamentary coated superconductors subjected to ac transverse magnetic fields

    NASA Astrophysics Data System (ADS)

    Amemiya, Naoyuki; Sato, Susumu; Ito, Takeshi

    2006-12-01

    ac losses in superconductors are generated by the magnetic flux and current penetration into them. To reveal the magnetic flux and current penetration processes in twisted multifilamentary coated superconductors in which the thin superconductor layer is subdivided into filaments and then twisted as a whole for ac loss reduction, a theoretical model for electromagnetic field analysis was developed based on the power law E-J (electric-field-current-density) characteristic for the superconductor and a thin strip approximation of the conductor. The developed theoretical model was implemented into a numerical code using the finite element method to calculate and visualize the current and magnetic flux distributions. The magnetization losses in twisted multifilamentary coated superconductors exposed to ac transverse magnetic fields were calculated from the temporal evolutions of the current distribution to demonstrate the effect of the twisted multifilamentary architecture on ac loss reduction.

  19. Measurement of Recoil Losses and Ranges for Spallation Products Produced in Proton Interactions with Al, Si, Mg at 200 and 500 MeV

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.

    2005-01-01

    Cosmic rays interact with extraterrestrial materials to produce a variety of spallation products. If these cosmogenic nuclides are produced within an inclusion in such material, then an important consideration is the loss of the product nuclei, which recoil out of the inclusion. Of course, at the same time, some atoms of the product nuclei under study may be knocked into the inclusion from the surrounding material, which is likely to have a different composition to that of the inclusion [1]. For example, Ne-21 would be produced in presolar grains, such as SiC, when irradiated in interstellar space. However, to calculate a presolar age, one needs to know how much 21Ne is retained in the grain. For small grains, the recoil losses might be large [2, 3] To study this effect under laboratory conditions, recoil measurements were made using protons with energies from 66 - 1600 MeV on Si, Al and Ba targets [3, 4, 5].

  20. National measures under the chemical weapons convention to protect confidential business information and compensate for its loss

    SciTech Connect

    Tanzman, E.A.; Kellman, B.

    1995-07-01

    This report contains a discussion presented at the Regional Seminar on the National Authority and the Chemical Weapons Convention. Measures to protect confidential business information and compensation for information which has not been sufficiently protected is discussed.

  1. Absorption of Low-Loss Optical Materials Measured at 1064 nm by a Position-Modulated Collinear Photothermal Detection Technique

    NASA Astrophysics Data System (ADS)

    Loriette, Vincent; Boccara, Claude

    2003-02-01

    A collinear photothermal detection bench is described that makes use of a position-modulated heating source instead of the classic power-modulated source. This new modulation scheme increases by almost a factor 2 the sensitivity of a standard mirage bench. This bench is then used to measure the absorption coefficient of OH-free synthetic fused silica at 1064 nm in the parts per 106 range, which, combined with spectrophotometric measurements, confirms that the dominant absorption source is the OH content.

  2. Effectiveness of Conservation Measures in Reducing Runoff and Soil Loss Under Different Magnitude-Frequency Storms at Plot and Catchment Scales in the Semi-arid Agricultural Landscape.

    PubMed

    Zhu, T X

    2016-03-01

    In this study, multi-year stormflow data collected at both catchment and plot scales on an event basis were used to evaluate the efficiency of conservation. At the catchment scale, soil loss from YDG, an agricultural catchment with no conservation measures, was compared with that from CZG, an agricultural catchment with an implementation of a range of conservation measures. With an increase of storm recurrence intervals in the order of <1, 1-2, 2-5, 5-10, 10-20, and >20 years, the mean event sediment yield was 639, 1721, 5779, 15191, 19627, and 47924 t/km(2) in YDG, and was 244, 767, 3077, 4679, 8388, and 15868 t/km(2) in CZG, which represented a reduction effectiveness of 61.8, 55.4, 46.7, 69.2, 57.2, and 66.8 %, respectively. Storm events with recurrence intervals greater than 2 years contributed about two-thirds of the total runoff and sediment in both YDG and CZG catchments. At the plot scale, soil loss from one cultivated slopeland was compared with that from five conservation plots. The mean event soil loss was 1622 t/km(2) on the cultivated slopeland, in comparison to 27.7 t/km(2) on the woodland plot, 213 t/km(2) on the grassland plot, 467 t/km(2) on the alfalfa plot, 236 t/km(2) on the terraceland plot, and 642 t/km(2) on the earthbank plot. Soil loss per unit area from all the plots was significantly less than that from the catchments for storms of all categories of recurrence intervals. PMID:26645075

  3. Effectiveness of Conservation Measures in Reducing Runoff and Soil Loss Under Different Magnitude-Frequency Storms at Plot and Catchment Scales in the Semi-arid Agricultural Landscape

    NASA Astrophysics Data System (ADS)

    Zhu, T. X.

    2016-03-01

    In this study, multi-year stormflow data collected at both catchment and plot scales on an event basis were used to evaluate the efficiency of conservation. At the catchment scale, soil loss from YDG, an agricultural catchment with no conservation measures, was compared with that from CZG, an agricultural catchment with an implementation of a range of conservation measures. With an increase of storm recurrence intervals in the order of <1, 1-2, 2-5, 5-10, 10-20, and >20 years, the mean event sediment yield was 639, 1721, 5779, 15191, 19627, and 47924 t/km2 in YDG, and was 244, 767, 3077, 4679, 8388, and 15868 t/km2 in CZG, which represented a reduction effectiveness of 61.8, 55.4, 46.7, 69.2, 57.2, and 66.8 %, respectively. Storm events with recurrence intervals greater than 2 years contributed about two-thirds of the total runoff and sediment in both YDG and CZG catchments. At the plot scale, soil loss from one cultivated slopeland was compared with that from five conservation plots. The mean event soil loss was 1622 t/km2 on the cultivated slopeland, in comparison to 27.7 t/km2 on the woodland plot, 213 t/km2 on the grassland plot, 467 t/km2 on the alfalfa plot, 236 t/km2 on the terraceland plot, and 642 t/km2 on the earthbank plot. Soil loss per unit area from all the plots was significantly less than that from the catchments for storms of all categories of recurrence intervals.

  4. AC magnetic susceptibility of Bi2223-system

    NASA Astrophysics Data System (ADS)

    Kimishima, Y.; Inagaki, K.; Tanabe, K.; Nagata, N.; Ichiyanagi, Y.

    1998-01-01

    The AC magnetic susceptibilities χ AC of a Bi2223 sintered sample were measured by the Hartshorn bridge method. The linear AC χ' 0 showed the two-steps behavior at T C1 and T C2, where T C1 > T C2. The χ'0-data between T C1 and T C2 has no H AC-dependence and agreed well with those of powder specimen, and they can be regarded as the intragrain magnetic susceptibility. Below the inter-grain transition temperature T C2 the χ″ 0 showed a positive peak. The temperature dependence of χ' 0 and χ″ 0 were analyzed by the Bean's critical-state model. As a result, the temperature dependence of critical current density J C ∝ (1 - T/T C2) β was obtained with β = 2.3-2.6. The non-linear χ' 2 and χ″ 2 below T C2 resemble the behaviors derived from the Bean model, but the negative divergence of χ' 2 may show the evidence of d-wave paring in the present Bi2223-system.

  5. Inelastic mean-free paths and surface excitation parameters by absolute reflection electron-energy loss measurements

    NASA Astrophysics Data System (ADS)

    Nagatomi, T.; Goto, K.

    2007-06-01

    An analytical approach is proposed for simultaneously determining the inelastic mean-free path (IMFP), the surface excitation parameter (SEP), and the differential SEP (DSEP) in absolute units from an absolute reflection electron energy loss spectroscopy (REELS) spectrum under the assumption that the normalized differential inelastic mean-free path for bulk excitations and the elastic scattering cross section are known. This approach was applied to an analysis of REELS spectra for Ni, and the IMFP, SEP, and DSEP in Ni for 300-3000eV electrons were determined. The resulting IMFPs showed good agreement with those calculated using the TPP-2M predictive equations and with those calculated from optical data. The deduced DSEPs show a reasonable agreement with those theoretically predicted. The obtained SEPs were compared with those calculated using several predictive equations. The present SEP results agreed well with the Chen formula with a material parameter proposed for Ni. The present approach has high potential for the experimental determination of IMFPs, SEPs, and DSEPs in absolute units.

  6. Absorption of low-loss optical materials measured at 1064 nm by a position-modulated collinear photothermal detection technique.

    PubMed

    Loriette, Vincent; Boccara, Claude

    2003-02-01

    A collinear photothermal detection bench is described that makes use of a position-modulated heating source instead of the classic power-modulated source. This new modulation scheme increases by almost a factor 2 the sensitivity of a standard mirage bench. This bench is then used to measure the absorption coefficient of OH-free synthetic fused silica at 1064 nm in the parts per 10(6) range, which, combined with spectrophotometric measurements, confirms that the dominant absorption source is the OH content. PMID:12564484

  7. CEBAF beam loss accounting

    SciTech Connect

    Ursic, R.; Mahoney, K.; Hovater, C.; Hutton, A.; Sinclair, C.

    1995-12-31

    This paper describes the design and implementation of a beam loss accounting system for the CEBAF electron accelerator. This system samples the beam curent throughout the beam path and measures the beam current accurately. Personnel Safety and Machine Protection systems use this system to turn off the beam when hazardous beam losses occur.

  8. AC Dielectric Properties and Positron Annihilation Study on Co and Ti Substitution Effect on Ca-Sr M-Hexaferrites

    NASA Astrophysics Data System (ADS)

    Mahmoud, K. R.; Eraky, M. R.

    2016-06-01

    The dependence of AC conductivity σ AC, dielectric constant έ, and dielectric loss tangent tan δ on frequency and composition have been investigated at room temperature for polycrystalline Ca0.5Sr0.5Co x Ti x Fe12 - 2 x O19 (where 0.0 ≤ x ≤ 0.8) hexaferrites. It was found that the parameters σ AC, ɛ ', and tan δ have maximum values at x = 0.4 of the Co and Ti substitution. The behavior of σ AC, ɛ ', and tan δ with frequency and composition was explained on the basis of the hopping conduction mechanism and the Koops model. Positron annihilation lifetime spectroscopy (PALS) was used to investigate the defects and changes in electron density for hexaferrite samples. The PAL parameters ( τ 1, I 1, τ 2, I 2, and mean lifetime) show that altering the doping percentage of the Co and Ti ions affects the size and concentration of defects. The results reveal that there are some large voids in the studied samples. The obtained results indicate the high sensitivity of the PALS technique to the enhanced structure changes with changing composition of the investigated samples and correlate the results with the measured electrical parameters.

  9. Cooling Floor AC Systems

    NASA Astrophysics Data System (ADS)

    Jun, Lu; Hao, Ding; Hong, Zhang; Ce, Gao Dian

    The present HVAC equipments for the residential buildings in the Hot-summer-and-Cold-winter climate region are still at a high energy consuming level. So that the high efficiency HVAC system is an urgently need for achieving the preset government energy saving goal. With its advantage of highly sanitary, highly comfortable and uniform of temperature field, the hot-water resource floor radiation heating system has been widely accepted. This paper has put forward a new way in air-conditioning, which combines the fresh-air supply unit and such floor radiation system for the dehumidification and cooling in summer or heating in winter. By analyze its advantages and limitations, we found that this so called Cooling/ Heating Floor AC System can improve the IAQ of residential building while keep high efficiency quality. We also recommend a methodology for the HVAC system designing, which will ensure the reduction of energy cost of users.

  10. Measuring Inductive-Heating Coupling Coefficients and Thermal Loss Characteristics as a Function of Crucible Geometry and Material Selection

    NASA Astrophysics Data System (ADS)

    Gomes, Jay

    A power measurement system has been designed for an ultra-high temperature inductively heated molten oxide electrolysis (MOE) reactor. The work presented in this research contributes to three different aspects of the induction heated MOE reactor facility: mathematical modeling of coil-to-workpiece power transfer, numerical modeling of heat transfer within the reactor, and experiments to measure the total hemispherical emittance of potential crucible materials. Facility-specific coupling coefficients for various samples have been experimentally determined for the MOE reactor facility. An analytical model coupling the predicted power input with heat transfer software was developed using COMSOL Multiphysics, and validated with experimental measurements of the steady state temperature gradient inside the reactor. These models were used to support the design of an experiment to measure the total hemispherical emissivity (epsilon) of conductive samples using a transient calorimetric technique. Results of epsilon are presented over a wide range of temperatures for copper, nickel, graphite and molybdenum. Furthermore, an investigation into optimizing the reactor system for heating will be discussed.

  11. Mitigation measures to reduce losses of phosphorus during the non-cropping period - a northern European perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Degradation of natural waters by phosphorus (P) due to agricultural activities has been a problem in several countries for many years. Accordingly, mitigation measures to minimize this issue have been developed and used with varying success. Non-point source P from agricultural fields is one of the ...

  12. Modelling Energy Loss Mechanisms and a Determination of the Electron Energy Scale for the CDF Run II W Mass Measurement

    SciTech Connect

    Riddick, Thomas

    2012-06-15

    The calibration of the calorimeter energy scale is vital to measuring the mass of the W boson at CDF Run II. For the second measurement of the W boson mass at CDF Run II, two independent simulations were developed. This thesis presents a detailed description of the modification and validation of Bremsstrahlung and pair production modelling in one of these simulations, UCL Fast Simulation, comparing to both geant4 and real data where appropriate. The total systematic uncertainty on the measurement of the W boson mass in the W → eve channel from residual inaccuracies in Bremsstrahlung modelling is estimated as 6.2 ±3.2 MeV/c2 and the total systematic uncertainty from residual inaccuracies in pair production modelling is estimated as 2.8± 2.7 MeV=c2. Two independent methods are used to calibrate the calorimeter energy scale in UCL Fast Simulation; the results of these two methods are compared to produce a measurement of the Z boson mass as a cross-check on the accuracy of the simulation.

  13. An H2A Histone Isotype, H2ac, Associates with Telomere and Maintains Telomere Integrity

    PubMed Central

    Tzeng, Tsai-Yu; Lin, I-Hsuan; Hsu, Ming-Ta

    2016-01-01

    Telomeres are capped at the ends of eukaryotic chromosomes and are composed of TTAGGG repeats bound to the shelterin complex. Here we report that a replication-dependent histone H2A isotype, H2ac, was associated with telomeres in human cells and co-immunoprecipitates with telomere repeat factor 2 (TRF2) and protection of telomeres protein 1 (POT1), whereas other histone H2A isotypes and mutations of H2ac did not bind to telomeres or these two proteins. The amino terminal basic domain of TRF2 was necessary for the association with H2ac and for the recruitment of H2ac to telomeres. Depletion of H2ac led to loss of telomeric repeat sequences, the appearance of dysfunctional telomeres, and chromosomal instability, including chromosomal breaks and anaphase bridges, as well as accumulation of telomere-associated DNA damage factors in H2ac depleted cells. Additionally, knockdown of H2ac elicits an ATM-dependent DNA damage response at telomeres and depletion of XPF protects telomeres against H2ac-deficiency-induced G-strand overhangs loss and DNA damage response, and prevents chromosomal instability. These findings suggest that the H2A isotype, H2ac, plays an essential role in maintaining telomere functional integrity. PMID:27228173

  14. Measurements of discharge, gain or loss in flow, and chemical quality of the Poplar and Redwater Rivers, northeastern Montana, October 24-25, 1979

    USGS Publications Warehouse

    Dodge, Kent A.; Levings, Gary W.

    1980-01-01

    Discharge, specific conductance, and water temperature were measured at 37 sites on the Poplar and Redwater Rivers in northeastern Montana on October 24-25, 1979, to provide data on the interaction between surface-water and groundwater systems. Streamflow gains or losses were computed for those stream reaches not significantly affected by irrigation. Water samples were collected at 17 of the sites for detailed chemical-quality analysis. The tabulated data provide an areally broad data base of concurrent base-flow conditions. (USGS)

  15. Large aperture ac interferometer for optical testing.

    PubMed

    Moore, D T; Murray, R; Neves, F B

    1978-12-15

    A 20-cm clear aperture modified Twyman-Green interferometer is described. The system measures phase with an AC technique called phase-lock interferometry while scanning the aperture with a dual galvanometer scanning system. Position information and phase are stored in a minicomputer with disk storage. This information is manipulated with associated software, and the wavefront deformation due to a test component is graphically displayed in perspective and contour on a CRT terminal. PMID:20208642

  16. Precision measurement of a low-loss cylindrical dumbbell-shaped sapphire mechanical oscillator using radiation pressure

    NASA Astrophysics Data System (ADS)

    Bourhill, J.; Ivanov, E.; Tobar, M. E.

    2015-08-01

    We present first results from a number of experiments conducted on a 0.53-kg cylindrical dumbbell-shaped sapphire crystal. Here we report on an optomechanical experiment utilizing a modification to the typical cylindrical architecture. Mechanical motion of the crystal structure alters the dimensions of the crystal, and the induced strain changes the permittivity. These two effects result in parametric frequency modulation of resonant microwave whispering gallery modes that are simultaneously excited within the crystal. A microwave readout system is implemented, allowing extremely low noise measurements of this frequency modulation near our modes of interest, having a phase noise floor of -165 dBc/Hz at 100 kHz. Fine tuning of the crystal's suspension has allowed for the optimization of mechanical quality factors in preparation for cryogenic experiments, with a value of Q =8 ×107 achieved at 127 kHz. This results in a Q ×f product of 1013, equivalent to the best measured values in a macroscopic sapphire mechanical system. Results are presented that demonstrate the excitation of mechanical modes via radiation pressure force, allowing an experimental method of determining the transducer's displacement sensitivity d f /d x and calibrating the system. Finally, we demonstrate parametric backaction phenomenon within the system. These are all important steps towards the goal of achieving quantum limited measurements of a kilogram-scale macroscopic device for the purpose of detecting deviations from standard quantum theory resulting from quantum gravitational effects.

  17. Measuring Property Management Risk and Loss: Step One Toward Managing Property on a Foundation of Risk, Cost, and Benefit

    SciTech Connect

    Johnson, Curtis

    1999-05-17

    This is a period of ever-tightening defense budgets and continuing pressure on the public sector to be more commercial-like, Property policies, practices, and regulations are increasingly being challenged and changed. In these times, we must be leaders in understanding and defining the value of our profession from a commercial standpoint so that we can provide the right services to our customers and explain and defend the value of those services. To do so, we must step outside current property management practices, regulations, and oversight. We must learn to think and speak in the language of those who fund us--a financial language of risk, cost, and benefit. Regardless of regulation and oversight, our bosses are demanding that we demonstrate (financially) the benefits of current practice, or else. This article is intended to be the beginning of an effort to understand and define our profession in terms of risk, cost, and benefit so that we can meet these new challenges. The first step in this effort must be defining and measuring risk, cost, and benefit. Our costs, although sometimes difficult to capture, are easy to understand: they are almost exclusively the effort, both within and without the property management organization, involved in managing property. Unfortunately, property risks and benefits are not so simple or so well understood. Generally, risks and benefits are identified and measured through physical inventory results: potential and actual shortages. This paper will explore the weaknesses in the current understanding and use of shortage information as the yardstick for property management risks and performance. It will define a new framework for understanding the purpose and value of property management. And finally, it will set a course for a new method of measuring and valuing physical inventoty shortages. This new method will yield accurate and useful measures of property management risk and benefit. Once risk and benefit are accurately

  18. Development of an AC Module System: Final Technical Report

    SciTech Connect

    Suparna Kadam; Miles Russell

    2012-06-15

    The GreenRay Inc. program focused on simplifying solar electricity and making it affordable and accessible to the mainstream population. This was accomplished by integrating a solar module, micro-inverter, mounting and monitoring into a reliable, 'plug and play' AC system for residential rooftops, offering the following advantages: (1) Reduced Cost: Reduction in installation labor with fewer components, faster mounting, faster wiring. (2) Maximized Energy Production: Each AC Module operates at its maximum, reducing overall losses from shading, mismatch, or module downtime. (3) Increased Safety. Electrical and fire safety experts agree that AC Modules have significant benefits, with no energized wiring or live connections during installation, maintenance or emergency conditions. (4) Simplified PV for a Broader Group of Installers. Dramatic simplification of design and installation of a solar power system, enabling faster and more efficient delivery of the product into the market through well-established, mainstream channels. This makes solar more accessible to the public. (5) Broadened the Rooftop Market: AC Modules enable solar for many homes that have shading, split roofs, or obstructions. In addition, due to the smaller building block size of 200W vs. 1000W, homeowners with budget limitations can start small and add to their systems over time. Through this DOE program GreenRay developed the all-in-one AC Module system with an integrated PV Module and microinverter, custom residential mounting and performance monitoring. Development efforts took the product from its initial concept, through prototypes, to a commercial product sold and deployed in the residential market. This pilot deployment has demonstrated the technical effectiveness of the AC Module system in meeting the needs and solving the problems of the residential market. While more expensive than the traditional central inverter systems at the pilot scale, the economics of AC Modules become more and more

  19. Low-frequency echo-reduction and insertion-loss measurements from small passive-material samples under ocean environmental temperatures and hydrostatic pressures.

    PubMed

    Piquette, J C; Forsythe, S E

    2001-10-01

    System L is a horizontal tube designed for acoustical testing of underwater materials and devices, and is part of the Low Frequency Facility of the Naval Undersea Warfare Center in Newport, Rhode Island. The tube contains a fill fluid that is composed of a propylene glycol/water mixture. This system is capable of achieving test temperatures in the range of -3 to 40 deg Centigrade, and hydrostatic test pressures in the range 40 to 68,950 kPa. A unidirectional traveling wave can be established within the tube over frequencies of 100 to 1750 Hz. Described here is a technique for measuring the (normal-incidence) echo reduction and insertion loss of small passive-material samples that approximately fill the tube diameter of 38 cm. (Presented also is a waveguide model that corrects the measurements when the sample fills the tube diameter incompletely.) The validity of the system L measurements was established by comparison with measurements acquired in a large acoustic pressure-test vessel using a relatively large panel of a candidate material, a subsample of which was subsequently evaluated in system L. The first step in effecting the comparison was to least-squares fit the data acquired from the large panel to a causal material model. The material model was used to extrapolate the panel measurements into the frequency range of system L. The extrapolations show good agreement with the direct measurements acquired in system L. PMID:11681380

  20. Initial tests of an AC dipole for the Tevatron

    SciTech Connect

    Miyamoto, R.; Jansson, A.; Kopp, S.; Syphers, M.; /Fermilab

    2006-06-01

    The AC dipole is a device to diagnose transverse motions of a beam. It can achieve large-amplitude oscillations without two inevitable problems of conventional kicker/pinger magnets: decoherence and emittance growth. While not the first synchrotron to operate with an AC dipole, the Tevatron can now make use of its recently upgraded BPM system, providing unprecedented resolution for use with an AC dipole, to measure both linear and nonlinear properties of the accelerator. Plans are to provide AC dipole systems for both transverse degrees of freedom. Preliminary tests have been done using an audio power amplifier with an existing vertical pinger magnet, producing oscillation amplitudes up to 2{sigma} at 150 GeV. In this paper, we will present the configuration of this system. We also show the analysis of a first few data sets, including the direct measurement of beta functions at BPM locations.