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Sample records for ac conductivity results

  1. Impedance, AC conductivity and dielectric behavior Adeninium Trichloromercurate (II)

    NASA Astrophysics Data System (ADS)

    Fersi, M. Amine; Chaabane, I.; Gargouri, M.

    2016-09-01

    In this work, we report the measurements impedance spectroscopy technique for the organic-inorganic hybrid compound (C5H6N5) HgCl3, 11/2H2O measured in the 209 Hz-5 MHz frequency range from 378 to 428 K. Besides, the Cole-Cole (Z″ versus Z‧) plots were well fitted to an equivalent circuit built up by a parallel combination of resistance (R), fractal capacitance (CPE) and capacitance (C). Furthermore, the AC conductivity was investigated as a function of temperature and frequency in the same range. The experiment results indicated that AC conductivityac) was proportional to σdc + A ωS . The obtained results are discussed in terms of the correlated barrier hopping (CBH) model. An agreement between the experimental and theoretical results suggests that the AC conductivity behavior of Adeninium Trichloromercurate (II) can be successfully explained by CBH model. The contribution of single polaron hopping to AC conductivity in a present alloy was also studied.

  2. Study of AC electrical conduction mechanisms in an epoxy polymer

    NASA Astrophysics Data System (ADS)

    Jilani, Wissal; Mzabi, Nissaf; Gallot-Lavallée, Olivier; Fourati, Najla; Zerrouki, Chouki; Zerrouki, Rachida; Guermazi, Hajer

    2015-11-01

    The AC conductivity of an epoxy resin was investigated in the frequency range 10^{-1} - 106 Hz at temperatures ranging from -100 to 120 °C. The frequency dependence of σ_{ac} was described by the law: σ_{ac}=ω \\varepsilon0\\varepsilon^''_{HN}+Aωs. The study of temperature variation of the exponent (s) reveals two conduction models: the AC conduction dependence upon temperature is governed by the small polaron tunneling mechanism (SPTM) at low temperature (-100 -60 °C) and the correlated barrier hopping (CHB) model at high temperature (80-120 °C).

  3. Evolution of AC conductivity of wet illitic clay during drying

    NASA Astrophysics Data System (ADS)

    Csáki, Š.; Štubňa, I.; Trnovcová, V.; Ondruška, J.; Vozár, L.; Dobroň, P.

    2017-02-01

    The evolution of the AC electrical conductivity during drying as well as the relationship between sample volume and moisture of green illite samples were investigated. The samples were prepared from illitic clay (80 mass % illite, 4 mass % montmorillonite, 12 mass % quartz and 4 mass % of orthoclase) and distilled water with initial moisture content 36 mass % and were freely dried in air. Conductivity was measured by the volt-ampere method with AC power supply of 5 V in the frequency range from 50 Hz to 10 kHz. The AC conductivity steeply increased with increasing moisture, up to 15 mass %. At higher values of the moisture, the AC conductivity was high and almost constant. The volume of samples increased with increasing moisture when the moisture was higher than 8 mass %. Below this value, the dimensions of samples do not significantly change. The dependence of the relative volume change on moisture is presented in a form of the Bigot’s curve.

  4. AC Conductivity Studies of Lithium Based Phospho Vanadate Glasses

    NASA Astrophysics Data System (ADS)

    Nagendra, K.; Babu, G. Satish; Reddy, C. Narayana; Gowda, Veeranna

    2011-07-01

    Glasses in the system xLi2SO4-20Li2O-(80-x) [80P2O5-20V2O5] (5⩾x⩾20 mol%) has been prepared by melt quenching method. Dc and ac conductivity has been studied over a wide range of frequency (10 Hz to 10 MHz) and temperature (298 K-523 K). The dc conductivity found to increase with increase of Li2SO4 concentration. The ac conductivities have been fitted to the Almond-West type single power law equation σ(ω) = σ(0)+Aωs where `s' is the power law exponent. The ac conductivity found to increase with increase of Li2SO4 concentration. An attempt is made to elucidate the enhancement of lithium ion conduction in phosphor-vanadate glasses by considering the expansion of network structure.

  5. AC conductivity of a niobium thin film in a swept magnetic field.

    PubMed

    Tsindlekht, M I; Genkin, V M; Gazi, S; Chromik, S

    2013-02-27

    We report results of measurements of the ac conductivity of a Nb superconducting thin film in a swept dc magnetic field. In the mixed state the swept dc field creates vortices at the film surface which pass through the film and form the observed ac conductivity. Vortex rate generation does not depend on the value of the dc field and there is a large plateau-like region of dc magnetic fields where the dissipation is approximately constant. A proposed phenomenological model describes quite well the main features of the ac response in these fields, including its dependency on the sweep rate, ac amplitude, frequency, and value of the second and third harmonics.

  6. AC Conductivity Studies of Lithium Based Phospho Vanadate Glasses

    SciTech Connect

    Nagendra, K.; Babu, G. Satish; Gowda, Veeranna; Reddy, C. Narayana

    2011-07-15

    Glasses in the system xLi{sub 2}SO{sub 4}-20Li{sub 2}O-(80-x) [80P{sub 2}O{sub 5}-20V{sub 2}O{sub 5}](5{>=}x{>=}20 mol%) has been prepared by melt quenching method. Dc and ac conductivity has been studied over a wide range of frequency (10 Hz to 10 MHz) and temperature (298 K-523 K). The dc conductivity found to increase with increase of Li{sub 2}SO{sub 4} concentration. The ac conductivities have been fitted to the Almond-West type single power law equation {sigma}({omega}) = {sigma}(0)+A{omega}{sup s} where 's' is the power law exponent. The ac conductivity found to increase with increase of Li{sub 2}SO{sub 4} concentration. An attempt is made to elucidate the enhancement of lithium ion conduction in phosphor-vanadate glasses by considering the expansion of network structure.

  7. AC Conductivity and Dielectric Properties of Borotellurite Glass

    NASA Astrophysics Data System (ADS)

    Taha, T. A.; Azab, A. A.

    2016-10-01

    Borotellurite glasses with formula 60B2O3-10ZnO-(30 - x)NaF- xTeO2 ( x = 0 mol.%, 5 mol.%, 10 mol.%, and 15 mol.%) have been synthesized by thermal melting. X-ray diffraction (XRD) analysis confirmed that the glasses were amorphous. The glass density ( ρ) was determined by the Archimedes method at room temperature. The density ( ρ) and molar volume ( V m) were found to increase with increasing TeO2 content. The direct-current (DC) conductivity was measured in the temperature range from 473 K to 623 K, in which the electrical activation energy of ionic conduction increased from 0.27 eV to 0.48 eV with increasing TeO2 content from 0 mol.% to 15 mol.%. The dielectric parameters and alternating-current (AC) conductivity ( σ ac) were investigated in the frequency range from 1 kHz to 1 MHz and temperature range from 300 K to 633 K. The AC conductivity and dielectric constant decreased with increasing TeO2 content from 0 mol.% to 15 mol.%.

  8. Broadband AC Conductivity of XUV Excited Warm Dense Gold

    NASA Astrophysics Data System (ADS)

    Chen, Z.; Tsui, Y.; Toleikis, S.; Hering, P.; Brown, S.; Curry, C.; Tanikawa, T.; Hoeppner, H.; Levy, M.; Goede, S.; Ziaja-Motyka, B.; Rethfeld, B.; Recoules, Vanina; Ng, A.; Glenzer, S.

    2015-11-01

    The properties of ultrafast laser excited warm dense gold have been extensively studied in the past decade. In those studies, a 400nm ultrashort laser pulse was used to excite the 5 d electrons in gold to 6s/p state. Here we will present our recent study of warm dense gold with 245eV, 70fs pulses to selectively excite 4 f electrons using the XUV-FEL at FLASH. The AC conductivity of the warm dense gold was measured at different wavelengths (485nm, 520nm, 585nm, 640nm and 720nm) to cover the range from 5 d-6 s / p interband transitions to 6 s/ p intraband transitions. Preliminary result suggests that the onset of 5 d-6 s / p band transition shifts from 2.3eV to ~ 2eV, which is in agreement with the study of 400nm laser pulse excited warm dense gold. More detailed analysis of our data will also be presented.

  9. Investigation on the AC loss characteristics of MgB 2 wires by using a conduction cooling device

    NASA Astrophysics Data System (ADS)

    Jin, H. B.; Li, Z.; Ryu, K.

    2011-11-01

    In this study, we have experimentally investigated the AC loss characteristics of MgB2 wires with matrix of Fe and Cu by using a conduction cooling device. We fabricated the conduction cooling device to cool MgB2 wires down to 4 K. We also developed our unique test method, which is called AC pulse technique, to evaluate their AC loss characteristics within few hundred milliseconds. The test results show that the AC loss of the Fe/MgB2 wire is mainly generated in the ferromagnetic Fe matrix. Its AC loss is ten times larger than that of the Cu/MgB2 wire. In this paper, the evaluation technique of AC loss by using the conduction cooling device is described and the test results are discussed.

  10. Correction of the power law of ac conductivity in ion-conducting materials due to the electrode polarization effect.

    PubMed

    Khamzin, A A; Popov, I I; Nigmatullin, R R

    2014-03-01

    Based on the supposition related to fractal nature of transport processes in ion-conducting materials, an expression for the low-frequency ac conductivity dependence was derived. This expression for the ac conductivity generalizes the power-law dependence and gives a possibility to take into account the influence of the electrode polarization effect. The ac conductivity expression obtained is in excellent agreement with experimental data for a wide frequency range.

  11. ac and dc percolative conductivity of magnetite-cellulose acetate composites

    SciTech Connect

    Chiteme, C.; McLachlan, D. S.; Sauti, G.

    2007-03-01

    ac and dc conductivity results for a percolating system, which consists of a conducting powder (magnetite) combined with an 'insulating' powder (cellulose acetate), are presented. Impedance and modulus spectra are obtained in a percolation system. The temperature dependence of the resistivity of the cellulose acetate is such that at 170 deg. C, it is essentially a conductor at frequencies below 0.059{+-}0.002 Hz, and a dielectric above. The percolation parameters, from the dc conductivity measured at 25 and 170 deg. C, are determined and discussed in relation to the ac results. The experimental results scale as a function of composition, temperature, and frequency. An interesting result is the correlation observed between the scaling parameter (f{sub ce}), obtained from a scaling of the ac measurements, and the peak frequency (f{sub cp}) of the arcs, obtained from impedance spectra, above the critical volume fraction. Scaling at 170 deg. C is not as good as at 25 deg. C, probably indicating a breakdown in scaling at the higher temperature. The modulus plots show the presence of two materials: a conducting phase dominated by the cellulose acetate and the isolated conducting clusters below the critical volume fraction {phi}{sub c}, as well as the interconnected conducting clusters above {phi}{sub c}. These results are confirmed by computer simulations using the two exponent phenomenological percolation equation. These results emphasize the need to analyze ac conductivity results in terms of both impedance and modulus spectra in order to get more insight into the behavior of composite materials.

  12. Charging in the ac Conductance of a Double Barrier Resonant Tunneling Structure

    NASA Technical Reports Server (NTRS)

    Anantram, M. P.; Saini, Subhash (Technical Monitor)

    1998-01-01

    There have been many studies of the linear response ac conductance of a double barrier resonant tunneling structure (DBRTS), both at zero and finite dc biases. While these studies are important, they fail to self consistently include the effect of the time dependent charge density in the well. In this paper, we calculate the ac conductance at both zero and finite do biases by including the effect of the time dependent charge density in the well in a self consistent manner. The charge density in the well contributes to both the flow of displacement currents in the contacts and the time dependent potential in the well. We find that including these effects can make a significant difference to the ac conductance and the total ac current is not equal to the simple average of the non-selfconsistently calculated conduction currents in the two contacts. This is illustrated by comparing the results obtained with and without the effect of the time dependent charge density included correctly. Some possible experimental scenarios to observe these effects are suggested.

  13. Influence of temperature on AC conductivity of nanocrystalline CuAlO2

    NASA Astrophysics Data System (ADS)

    Prakash, T.

    2012-07-01

    Nanocrystalline CuAlO2 was synthesized by mechanical alloying of Cu2O and α-Al2O3 powders in the molar ratio of 1:1 for 20 h in toluene medium with tungsten carbide balls and vials using planetary ball mill. The ball milling was carried out at 300 rpm with a ball to powder weight ratio of 10:1 and then annealed at 1373 K in a platinum crucible for 20 h to get CuAlO2 phase with average crystallite size 45 nm. Complex impedance spectroscopic measurement in the frequency region 1 Hz to 10 MHz between the temperatures 333 to 473 K was carried out for nanocrystalline CuAlO2 sample. The obtained complex impedance data was analyzed for AC conductivities, DC and AC conductivities correlations and crossover frequencies ( f co ). The BNN (Barton, Nakajima and Namikawa) relation was applied to understand the correlation between DC and AC conductivities. The observed experimental results were discussed in the paper.

  14. Polaron conductivity mechanism in potassium acid phthalate crystal: AC-conductivity investigation

    NASA Astrophysics Data System (ADS)

    Filipič, Cene; Levstik, Iva; Levstik, Adrijan; Hadži, Dušan

    2016-08-01

    The complex dielectric constant, \\varepsilon *(ν ,T), of potassium acid phthalate monocrystal (KAP) was investigated over the broad frequency and temperature range. While the imaginary part of dielectric constant ε‧‧(ν) increases rapidly with increasing temperature in the studied temperature range, the real part of dielectric constant ε‧(ν) increases only at high temperatures; there is almost no change of ε‧(ν) below 200 K. Both values of ε‧ and ε‧‧ are frequency dependent; the values increase with decreasing frequencies. At temperatures below 450 K the ac electrical conductivity and dielectric constant follow simultaneously the universal dielectric response (UDR). The analysis of the temperature dependence of the UDR parameter s in terms of the theoretical model for small polarons revealed that this mechanism governs the charge transport in KAP crystal in the studied temperature range.

  15. Electric properties of carbon nano-onion/polyaniline composites: a combined electric modulus and ac conductivity study

    NASA Astrophysics Data System (ADS)

    Papathanassiou, Anthony N.; Mykhailiv, Olena; Echegoyen, Luis; Sakellis, Ilias; Plonska-Brzezinska, Marta E.

    2016-07-01

    The complex electric modulus and the ac conductivity of carbon nano-onion/polyaniline composites were studied from 1 mHz to 1 MHz at isothermal conditions ranging from 15 K to room temperature. The temperature dependence of the electric modulus and the dc conductivity analyses indicate a couple of hopping mechanisms. The distinction between thermally activated processes and the determination of cross-over temperature were achieved by exploring the temperature dependence of the fractional exponent of the dispersive ac conductivity and the bifurcation of the scaled ac conductivity isotherms. The results are analyzed by combining the granular metal model (inter-grain charge tunneling of extended electron states located within mesoscopic highly conducting polyaniline grains) and a 3D Mott variable range hopping model (phonon assisted tunneling within the carbon nano-onions and clusters).

  16. Scaling of the holographic AC conductivity for non-Fermi liquids at criticality

    NASA Astrophysics Data System (ADS)

    Kiritsis, Elias; Peña-Benitez, Francisco

    2015-11-01

    The frequency dependence of the AC conductivity is studied in a holographic model of a non-fermi liquid that is amenable to both analytical and numerical computation. In the regime that dissipation dominates the DC conductivity, the AC conductivity is described well in the IR by a Drude peak despite the absence of quasiparticles. In the regime where pair-production-like processes dominate the conductivity there is no Drude peak. A scaling tail is found for the AC conductivity that is independent of the charge density and momentum dissipation. Evidence is given that this scaling tail σ AC ˜ ω m appears generically in quantum critical holographic systems and the associated scaling exponent m is calculated in terms of the Lifshitz and conduction critical exponents.

  17. Random free energy barrier hopping model for ac conduction in chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Murti, Ram; Tripathi, S. K.; Goyal, Navdeep; Prakash, Satya

    2016-03-01

    The random free energy barrier hopping model is proposed to explain the ac conductivityac) of chalcogenide glasses. The Coulomb correlation is consistently accounted for in the polarizability and defect distribution functions and the relaxation time is augmented to include the overlapping of hopping particle wave functions. It is observed that ac and dc conduction in chalcogenides are due to same mechanism and Meyer-Neldel (MN) rule is the consequence of temperature dependence of hopping barriers. The exponential parameter s is calculated and it is found that s is subjected to sample preparation and measurement conditions and its value can be less than or greater than one. The calculated results for a - Se, As2S3, As2Se3 and As2Te3 are found in close agreement with the experimental data. The bipolaron and single polaron hopping contributions dominates at lower and higher temperatures respectively and in addition to high energy optical phonons, low energy optical and high energy acoustic phonons also contribute to the hopping process. The variations of hopping distance with temperature is also studied. The estimated defect number density and static barrier heights are compared with other existing calculations.

  18. Effect of nanosilica on optical, electric modulus and AC conductivity of polyvinyl alcohol/polyaniline films

    NASA Astrophysics Data System (ADS)

    El-Sayed, Somyia; Abel-Baset, Tarob; Elfadl, Azza Abou; Hassen, Arafa

    2015-05-01

    Nanosilica (NS) was synthesized by a sol-gel method and mixed with 0.98 polyvinyl alcohol (PVA)/0.02 polyaniline (PANI) in different amounts to produce nanocomposite films. High-resolution transmission electron microscopy (HR-TEM) revealed the average particle size of the NS to be ca. 15 nm. Scanning electron microscopy (SEM) showed that the NS was well-dispersed on the surface of the PVA/PNAI films. The Fourier transform infrared (FTIR) spectra of the samples showed a significant change in the intensity of the characteristic peak of the functional groups in the composite films with the amount of NS added. The absorbance and refractive index (n) of the composites were studied in the UV-vis range, and the optical energy band gap, Eg, and different optical parameters were calculated. The dielectric loss modulus, M″ and ac conductivity, σac, of the samples were studied within 300-425 K and 0.1 kHz-5 MHz, respectively. Two relaxation peaks were observed in the frequency dependence of the dielectric loss modulus, M″. The behavior of σac(f) for the composite films indicated that the conduction mechanism was correlated barrier hopping (CBH). The results of this work are discussed and compared with those of previous studies of similar composites.

  19. AC motor controller with 180 degree conductive switches

    NASA Technical Reports Server (NTRS)

    Oximberg, Carol A. (Inventor)

    1995-01-01

    An ac motor controller is operated by a modified time-switching scheme where the switches of the inverter are on for electrical-phase-and-rotation intervals of 180.degree. as opposed to the conventional 120.degree.. The motor is provided with three-phase drive windings, a power inverter for power supplied from a dc power source consisting of six switches, and a motor controller which controls the current controlled switches in voltage-fed mode. During full power, each switch is gated continuously for three successive intervals of 60.degree. and modulated for only one of said intervals. Thus, during each 60.degree. interval, the two switches with like signs are on continuously and the switch with the opposite sign is modulated.

  20. Deletion of the AcMNPV core gene ac109 results in budded virions that are non-infectious

    SciTech Connect

    Fang Minggang; Nie, Yingchao; Theilmann, David A.

    2009-06-20

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac109 is a core gene and its function in the virus life cycle is unknown. To determine its role in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac109 deletion virus (vAc{sup 109KO}). Fluorescence and light microscopy showed that transfection of vAc{sup 109KO} results in a single-cell infection phenotype. Viral DNA replication is unaffected and the development of occlusion bodies in vAc{sup 109KO}-transfected cells evidenced progression to the very late phases of viral infection. Western blot and confocal immunofluorescence analysis showed that AC109 is expressed in the cytoplasm and nucleus throughout infection. In addition, AC109 is a structural protein as it was detected in both budded virus (BV) and occlusion derived virus in both the envelope and nucleocapsid fractions. Titration assays by qPCR and TCID{sub 50} showed that vAc{sup 109KO} produced BV but the virions are non-infectious. The vAc{sup 109KO} BV were indistinguishable from the BV of repaired and wild type control viruses as determined by negative staining and electron microscopy.

  1. Structural, dielectric and AC conductivity properties of Co2+ doped mixed alkali zinc borate glasses

    NASA Astrophysics Data System (ADS)

    Madhu, B. J.; Banu, Syed Asma; Harshitha, G. A.; Shilpa, T. M.; Shruthi, B.

    2013-02-01

    The Co2+ doped 19.9ZnO+5Li2CO3+25Na2CO3+50B2O3 (ZLNB) mixed alkali zinc borate glasses have been prepared by a conventional melt quenching method. The structural (XRD & FT-IR), dielectric and a.c. conductivityac) properties have been investigated. Amorphous nature of these glasses has been confirmed from their XRD pattern. The dielectric properties and electrical conductivityac) of these glasses have been studied from 100Hz to 5MHz at the room temperature. Based on the observed trends in the a.c. conductivities, the present glass samples are found to exhibit a non-Debye behavior.

  2. Ocular vestibular evoked myogenic potentials to air conduction (AC oVEMP): useful in clinical practice?

    PubMed

    Walther, L E; Rogowski, M; Hörmann, K; Schaaf, H; Löhler, J

    2011-01-01

    Cervical vestibular-evoked myogenic potential (cVEMP) and ocular VEMP (oVEMP) stimuli can be used to measure otolith function using air (AC) and bone conducted (BC) stimuli. Cervical VEMPs reflect saccular function and can be recorded using air conduction (AC), whereas oVEMPs reflect probably predominantly utricular function. Air- and bone-conducted vibration can be used, because AC oVEMP methodology seems to be fast and simple in clinical practice to measure otolith function. In this study we discuss the advantages and problems of AC oVEMP stimulation. AC oVEMP can be easily and quickly obtained within a few seconds. N10 (first negative peak) and p15 (first positive peak) latencies may be used as parameters for clinical interpretation but amplitude fluctuations are relatively large. For daily clinical use of VEMP visualization in a normogram seems feasible. Especially the AC oVEMP methodology (100 dB nHL, tone burst 500 Hz) is fast and efficient in clinical practice to measure otolith function, predominantly utricular function.

  3. AC and DC conductivity of ionic liquid containing polyvinylidene fluoride thin films

    NASA Astrophysics Data System (ADS)

    Frübing, Peter; Wang, Feipeng; Kühle, Till-Friedrich; Gerhard, Reimund

    2016-01-01

    Polarisation processes and charge transport in polyvinylidene fluoride (PVDF) with a small amount (0.01-10 wt%) of the ionic liquid (IL) 1-ethyl-3-methylimidazolium nitrate ({[EMIM]}^+[{NO}_3]^-) are investigated by means of dielectric spectroscopy. The response of PVDF that contains more than 0.01 wt% IL is dominated by a low-frequency relaxation which shows typical signatures of electrode polarisation. Furthermore, the α a relaxation, related to the glass transition, disappears for IL contents of more than 1 wt%, which indicates that the amorphous phase loses its glass-forming properties and undergoes structural changes. The DC conductivity is determined from the low-frequency limit of the AC conductivity and from the dielectric loss peak related to the electrode polarisation. DC conductivities of 10^{-10} to 10^{-2} {S}/{m} are obtained—increasing with IL content and temperature. The dependence of the DC conductivity on the IL content follows a power law with an exponent greater than one, indicating an increase in the ion mobility. The temperature dependence of the DC conductivity shows Vogel-Fulcher-Tammann behaviour, which implies that charge transport is coupled to polymer chain motion. Mobile ion densities and ion mobilities are calculated from the DC conductivity and the dielectric loss related to electrode polarisation, with the results that less than one per cent of the total ion concentration contributes to the conductivity and that the strong increase in conductivity with temperature is mainly caused by a strong increase in ion mobility. This leads to the conclusion that in particular the ion mobility must be reduced in order to decrease the DC conductivity.

  4. Ac-conductivity and dielectric response of new zinc-phosphate glass/metal composites

    NASA Astrophysics Data System (ADS)

    Maaroufi, A.; Oabi, O.; Lucas, B.

    2016-07-01

    The ac-conductivity and dielectric response of new composites based on zinc-phosphate glass with composition 45 mol%ZnO-55 mol%P2O5, filled with metallic powder of nickel (ZP/Ni) were investigated by impedance spectroscopy in the frequency range from 100 Hz to 1 MHz at room temperature. A high percolating jump of seven times has been observed in the conductivity behavior from low volume fraction of filler to the higher fractions, indicating an insulator - semiconductor phase transition. The measured conductivity at higher filler volume fraction is about 10-1 S/cm and is frequency independent, while, the obtained conductivity for low filler volume fraction is around 10-8 S/cm and is frequency dependent. Moreover, the elaborated composites are characterized by high dielectric constants in the range of 105 for conductive composites at low frequencies (100 Hz). In addition, the distribution of the relaxation processes was also evaluated. The Debye, Cole-Cole, Davidson-Cole and Havriliak-Negami models in electric modulus formalism were used to model the observed relaxation phenomena in ZP/Ni composites. The observed relaxation phenomena are fairly simulated by Davidson-Cole model, and an account of the interpretation of results is given.

  5. ac conductance in granular insulating Co-ZrO{sub 2} thin films: A universal response

    SciTech Connect

    Konstantinovic, Zorica; Garcia del Muro, Montserrat; Kovylina, Miroslavna; Batlle, Xavier; Labarta, Amilcar

    2009-03-01

    The ac conductance in granular insulating Co-ZrO{sub 2} thin films prepared by pulsed laser deposition is systematically studied as a function of the Co volume content x. An absorption phenomenon at low frequencies that mimics the universal response of disordered dielectric materials is observed in the range of metal content below the Co percolation threshold x{sub p}{approx_equal}0.35 in the so-called dielectric regime. The temperature and frequency dependences of this absorption phenomenon are successfully analyzed in terms of random competing conduction channels between Co particles through thermally assisted tunneling and capacitive conductance. The ac conductance is well correlated with the nanostructure of the samples obtained by the transmission electron microscopy and perfectly matches the calculated ac response for a random resistor-capacitor network. We also show the occurrence of fractional power-law dependences on the frequency of the ac conductance taking place at very low frequencies as compared to the typical ranges at which dispersive behavior is observed in classical-disordered dielectric materials.

  6. AC conductivity and structural properties of Mg-doped ZnO ceramic

    NASA Astrophysics Data System (ADS)

    Othman, Zayani Jaafar; Hafef, Olfa; Matoussi, Adel; Rossi, Francesca; Salviati, Giancarlo

    2015-11-01

    Undoped ZnO and Zn1- x Mg x O ceramic pellets were synthesized by the standard sintering method at the temperature of 1200 °C. The influence of Mg doping on the morphological, structural and electrical properties was studied. The scanning electron microscopy images revealed rough surface textured by grain boundaries and compacted grains having different shapes and sizes. Indeed, the X-ray diffraction reveals the alloying of hexagonal ZnMgO phase and the segregation of cubic MgO phase. The crystallite size, strain and stress were studied using Williamson-Hall (W-H) method. The results of mean particle size of Zn1- x Mg x O composites showed an inter-correlation with W-H analysis and Sherrer method. The electrical conductivity of the films was measured from 173 to 373 K in the frequency range of 0.1 Hz-1 MHz to identify the dominant conductivity mechanism. The DC conductivity is thermally activated by electron traps having activation energy of about 0.09 to 0.8 eV. The mechanisms of AC conductivity are controlled by the correlated barrier hopping model for the ZnO sample and the small polaron tunneling (SPT) model for Zn0.64Mg0.36O and Zn0.60Mg0.40O composites.

  7. Dielectric behavior and ac electrical conductivity in samarium substituted Mg-Ni ferrites

    NASA Astrophysics Data System (ADS)

    Melagiriyappa, E.; Veena, M.; Somashekarappa, A.; Shankaramurthy, G. J.; Jayanna, H. S.

    2014-08-01

    Samarium substituted MgNi ferrites with composition Mg1-xNixFe2-ySmyO4 ( x = 0, 0.2, 0.4, 0.6, 0.8, 1.0; y = 0.0, 0.05, 0.1) have been prepared by ceramic method. Dielectric measurements of the samples have been carried out at room temperature as a function of frequency and composition. X-ray diffraction patterns have confirmed the single-phase spinel cubic structure for all the samples. Dielectric constant ( ɛ') and dielectric loss (tan δ) decrease while ac electrical conductivity ( σ ac ) increases with increase in frequency. Dielectric properties have been explained on the basis of Maxwell-Wagner's two layer model. The conduction mechanism in these ferrites is due to electron hopping between Ni2+ and Ni3+ as well as Fe3+ and Fe2+ ions on octahedral sites. Dielectric constant and ac conductivity increases and decreases respectively with nickel content. A significant reduction in the values of dielectric constant and ac electrical conductivity has been observed in Sm3+ ions substituted samples.

  8. AC Conductivity Studies in Lithium-Borate Glass Containing Gold Nanoparticles

    NASA Astrophysics Data System (ADS)

    Shivaprakash, Y.; Anavekar, R. V.

    2011-07-01

    Gold nanoparticles have been synthesized in a base glass with composition 30Li2O-70B2O3 using gold chloride (HAuCl4.3H2O) as a dopant. The samples are characterized using XRD, ESR, SEM and optical absorption in the visible range. AC conductivity studies have been performed at RT over a frequency range 100 to 10 MHz. The dc conductivity is calculated from the complex impedence plot. The dc conductivity is found to be increasing with the increase of dopant concentration. AC conductivity data is fitted with Almond-West law with power exponent `s'. The values of `s' is found to lie in the range of 0.70-0.73.

  9. Transparent conducting materials: overview and recent results

    NASA Astrophysics Data System (ADS)

    van Deelen, Joop; Illiberi, Andrea; Hovestad, Arjan; Barbu, Ionut; Klerk, Lennaert; Buskens, Pascal

    2012-10-01

    An overview of different transparent conductors is given. In addition, atmospheric pressure CVD of ZnO resulted in conductivities below 1 mΩ cm for a temperature of 480°C, whereas at a process temperature of 200°C a value of 2 mΩ cm was obtained. Also atmospheric pressure spatial ALD was used to make conductive ZnO. Furthermore, the properties of transparent conductive oxides (TCO) can be enhanced by application of metallic grids. This way, sheet resistances of below 0.1 Ω/sq and transmittances above 85 % can be achieved. Modeling indicates that the performance of thin film cells can be enhanced by18% using a grid/TCO combination. Light scattering is a vital element of thin film solar cells and both texturization and multimaterial approaches for advanced light management such as plasmonics are discussed.

  10. Experimental and theoretical study of AC electrical conduction mechanisms of semicrystalline parylene C thin films.

    PubMed

    Kahouli, Abdelkader; Sylvestre, Alain; Jomni, Fethi; Yangui, Béchir; Legrand, Julien

    2012-01-26

    The electrical conduction mechanisms of semicrystalline thermoplastic parylene C (-H(2)C-C(6)H(3)Cl-CH(2)-)(n) thin films were studied in large temperature and frequency regions. The alternative current (AC) electrical conduction in parylene C is governed by two processes which can be ascribed to a hopping transport mechanism: correlated barrier hopping (CBH) model at low [77-155 K] and high [473-533 K] temperature and the small polaron tunneling mechanism (SPTM) from 193 to 413 K within the framework of the universal law of dielectric response. The conduction mechanism is explained with the help of Elliot's theory, and the Elliot's parameters are determined. From frequency- and temperature-conductivity characteristics, the activation energy is found to be 1.27 eV for direct current (DC) conduction interpreted in terms of ionic conduction mechanism. The power law dependence of AC conductivity is interpreted in terms of electron hopping with a density N(E(F)) (~10(18) eV cm(-3)) over a 0.023-0.03 eV high barrier across a distance of 1.46-1.54 Å.

  11. AC Conductivity and Diffuse Reflectance Studies of Ag-TiO2 Nanoparticles

    NASA Astrophysics Data System (ADS)

    Abdul Gafoor, A. K.; Musthafa, M. M.; Pradyumnan, P. P.

    2012-09-01

    Silver (Ag)-TiO2 nanoparticles synthesized by a low-temperature hydrothermal method in the anatase phase have been investigated by x-ray diffraction. Transmission electron microscopy has been used for morphological studies. Surface areas were studied by the Brunauer-Emmett-Teller method. Alternating-current (AC) conductivity and dielectric properties were studied for various dopant levels of 0.25 wt.%, 0.5 wt.%, and 1.0 wt.% at 300 K in the frequency range from 42 Hz to 5 MHz. AC conductivity and dielectric properties of TiO2 nanoparticles were greatly affected by loading with Ag. At high frequencies, the materials showed high AC conductivity and low dielectric constant. Diffuse reflectance studies were carried out for various dopant levels at 300 K by ultraviolet-visible (UV-Vis) spectroscopy. Considerable absorption of visible light by 0.5 wt.% and 1.0 wt.% Ag-TiO2 nanoparticles was observed due to the decrease of the energy band gap on Ag loading.

  12. Calculation of the ac to dc resistance ratio of conductive nonmagnetic straight conductors by applying FEM simulations

    NASA Astrophysics Data System (ADS)

    Riba, Jordi-Roger

    2015-09-01

    This paper analyzes the skin and proximity effects in different conductive nonmagnetic straight conductor configurations subjected to applied alternating currents and voltages. These effects have important consequences, including a rise of the ac resistance, which in turn increases power loss, thus limiting the rating for the conductor. Alternating current (ac) resistance is important in power conductors and bus bars for line frequency applications, as well as in smaller conductors for high frequency applications. Despite the importance of this topic, it is not usually analyzed in detail in undergraduate and even in graduate studies. To address this, this paper compares the results provided by available exact formulas for simple geometries with those obtained by means of two-dimensional finite element method (FEM) simulations and experimental results. The paper also shows that FEM results are very accurate and more general than those provided by the formulas, since FEM models can be applied in a wide range of electrical frequencies and configurations.

  13. Microwave a.c. conductivity of domain walls in ferroelectric thin films

    PubMed Central

    Tselev, Alexander; Yu, Pu; Cao, Ye; Dedon, Liv R.; Martin, Lane W.; Kalinin, Sergei V.; Maksymovych, Petro

    2016-01-01

    Ferroelectric domain walls are of great interest as elementary building blocks for future electronic devices due to their intrinsic few-nanometre width, multifunctional properties and field-controlled topology. To realize the electronic functions, domain walls are required to be electrically conducting and addressable non-destructively. However, these properties have been elusive because conducting walls have to be electrically charged, which makes them unstable and uncommon in ferroelectric materials. Here we reveal that spontaneous and recorded domain walls in thin films of lead zirconate and bismuth ferrite exhibit large conductance at microwave frequencies despite being insulating at d.c. We explain this effect by morphological roughening of the walls and local charges induced by disorder with the overall charge neutrality. a.c. conduction is immune to large contact resistance enabling completely non-destructive walls read-out. This demonstrates a technological potential for harnessing a.c. conduction for oxide electronics and other materials with poor d.c. conduction, particularly at the nanoscale. PMID:27240997

  14. Microwave a.c. conductivity of domain walls in ferroelectric thin films.

    PubMed

    Tselev, Alexander; Yu, Pu; Cao, Ye; Dedon, Liv R; Martin, Lane W; Kalinin, Sergei V; Maksymovych, Petro

    2016-05-31

    Ferroelectric domain walls are of great interest as elementary building blocks for future electronic devices due to their intrinsic few-nanometre width, multifunctional properties and field-controlled topology. To realize the electronic functions, domain walls are required to be electrically conducting and addressable non-destructively. However, these properties have been elusive because conducting walls have to be electrically charged, which makes them unstable and uncommon in ferroelectric materials. Here we reveal that spontaneous and recorded domain walls in thin films of lead zirconate and bismuth ferrite exhibit large conductance at microwave frequencies despite being insulating at d.c. We explain this effect by morphological roughening of the walls and local charges induced by disorder with the overall charge neutrality. a.c. conduction is immune to large contact resistance enabling completely non-destructive walls read-out. This demonstrates a technological potential for harnessing a.c. conduction for oxide electronics and other materials with poor d.c. conduction, particularly at the nanoscale.

  15. Microwave a.c. conductivity of domain walls in ferroelectric thin films

    SciTech Connect

    Tselev, Alexander; Yu, Pu; Cao, Ye; Dedon, Liv R.; Martin, Lane W.; Kalinin, Sergei V.; Maksymovych, Petro

    2016-05-31

    Ferroelectric domain walls are of great interest as elementary building blocks for future electronic devices due to their intrinsic few-nanometre width, multifunctional properties and field-controlled topology. To realize the electronic functions, domain walls are required to be electrically conducting and addressable non-destructively. However, these properties have been elusive because conducting walls have to be electrically charged, which makes them unstable and uncommon in ferroelectric materials. Here we reveal that spontaneous and recorded domain walls in thin films of lead zirconate and bismuth ferrite exhibit large conductance at microwave frequencies despite being insulating at d.c. We explain this effect by morphological roughening of the walls and local charges induced by disorder with the overall charge neutrality. a.c. conduction is immune to large contact resistance enabling completely non-destructive walls read-out. Finally, this demonstrates a technological potential for harnessing a.c. conduction for oxide electronics and other materials with poor d.c. conduction, particularly at the nanoscale.

  16. Microwave a.c. conductivity of domain walls in ferroelectric thin films

    DOE PAGES

    Tselev, Alexander; Yu, Pu; Cao, Ye; ...

    2016-05-31

    Ferroelectric domain walls are of great interest as elementary building blocks for future electronic devices due to their intrinsic few-nanometre width, multifunctional properties and field-controlled topology. To realize the electronic functions, domain walls are required to be electrically conducting and addressable non-destructively. However, these properties have been elusive because conducting walls have to be electrically charged, which makes them unstable and uncommon in ferroelectric materials. Here we reveal that spontaneous and recorded domain walls in thin films of lead zirconate and bismuth ferrite exhibit large conductance at microwave frequencies despite being insulating at d.c. We explain this effect by morphologicalmore » roughening of the walls and local charges induced by disorder with the overall charge neutrality. a.c. conduction is immune to large contact resistance enabling completely non-destructive walls read-out. Finally, this demonstrates a technological potential for harnessing a.c. conduction for oxide electronics and other materials with poor d.c. conduction, particularly at the nanoscale.« less

  17. Gas sensing properties of magnesium doped SnO{sub 2} thin films in relation to AC conduction

    SciTech Connect

    Deepa, S.; Skariah, Benoy Thomas, Boben; Joseph, Anisha

    2014-01-28

    Conducting magnesium doped (0 to 1.5 wt %) tin oxide thin films prepared by Spray Pyrolysis technique achieved detection of 1000 ppm of LPG. The films deposited at 304 °C exhibit an enhanced response at an operating temperature of 350 °C. The microstructural properties are studied by means of X-ray diffraction. AC conductivity measurements are carried out using precision LCR meter to analyze the parameters that affect the variation in sensing. The results are correlated with compositional parameters and the subsequent modification in the charge transport mechanism facilitating an enhanced LPG sensing action.

  18. Gas sensing properties of magnesium doped SnO2 thin films in relation to AC conduction

    NASA Astrophysics Data System (ADS)

    Deepa, S.; Joseph, Anisha; Skariah, Benoy; Thomas, Boben

    2014-01-01

    Conducting magnesium doped (0 to 1.5 wt %) tin oxide thin films prepared by Spray Pyrolysis technique achieved detection of 1000 ppm of LPG. The films deposited at 304 °C exhibit an enhanced response at an operating temperature of 350 °C. The microstructural properties are studied by means of X-ray diffraction. AC conductivity measurements are carried out using precision LCR meter to analyze the parameters that affect the variation in sensing. The results are correlated with compositional parameters and the subsequent modification in the charge transport mechanism facilitating an enhanced LPG sensing action.

  19. Temperature and frequency dependence of AC conductivity of new quaternary Se-Te-Bi-Pb chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Yadav, Preeti; Sharma, Ambika

    2016-05-01

    The aim of the present work is to study the temperature and frequency dependence of ac conductivity of new quaternary Se84-xTe15Bi1.0Pbx chalcogenide glasses. The Se84-xTe15Bi1.0Pbx (x = 2, 6) glassy alloys are prepared by using melt quenching technique. The temperature and frequency dependent behavior of ac conductivity σac(ω) has been carried out in the frequency range 42 Hz to 5 MHz and in the temperature range of 298-323 K below glass transition temperature. The behavior of ac conductivity is described in terms of the power law ωs. The obtained temperature dependence behavior of ac conductivity and frequency component (s) are explained by means of correlated barrier hopping model recommended by Elliot.

  20. Dielectric relaxation and ac conductivity behavior of carboxyl functionalized multiwalled carbon nanotubes/poly (vinyl alcohol) composites

    NASA Astrophysics Data System (ADS)

    Amrin, Sayed; Deshpande, V. D.

    2017-03-01

    We study the dielectric relaxation and ac conductivity behavior of MWCNT-COOH/Polyvinyl alcohol nanocomposite films in the temperature (T) range 303-423 K and in the frequency (f) range 0.1 Hz-1 MHz. The dielectric constant increases with an increase in temperature and also with an increase in MWCNT-COOH loading into the polymer matrix, as a result of interfacial polarization. The permittivity data were found to fit well with the modified Cole-Cole equation. Temperature dependent values of the relaxation times, free charge carrier conductivity and space charge carrier conductivity were extracted from the equation. An observed increment in the ac conductivity for the nanocomposites was analysed by a Jonscher power law which suggests that the correlated barrier hopping is the dominant charge transport mechanism for the nanocomposite films. The electric modulus study revealed deviations from ideal Debye-type behavior which are explained by considering a generalized susceptibility function. XRD and DSC results show an increase in the degree of crystallinity.

  1. AC impedance spectroscopy and conductivity studies of Dy doped Bi4V2O11 ceramics

    NASA Astrophysics Data System (ADS)

    Bag, Sasmitarani; Das, Parthasarathi; Behera, Banarji

    2017-03-01

    The ac impedance and conductivity properties of Dy doped Bi4V2 - x Dy x O11 (x = 0.05, 0.10, 0.15 and 0.20) ceramics prepared by solid-state reaction technique, in a wide frequency range at different temperatures have been studied. All the samples exhibited β-type phase orthorhombic structure at room temperature. The Nyquist plot confirmed the presence of both grain and grain boundary effects for all Dy doped samples. Double relaxation behavior was also observed. The grain and grain boundary resistance decreases with rise in temperature for all the concentration and exhibits a typical negative temperature co-efficient of resistance (NTCR) behavior. An analysis of the electric modulus suggests the possible hopping mechanism for electrical transport processes of all the materials. The ac conductivity spectrum obeys Jonscher's universal power law. DC conductivity of the materials were also studied and values of the activation energy found to be 0.40, 0.49, 0.73 and 0.78 eV for the compositions x = 0.05, 0.10, 0.15 and 0.20, respectively, at different temperatures (150-375 °C).

  2. Temperature characterization of dielectric permittivity and AC conductivity of nano copper oxide-doped polyaniline composite

    NASA Astrophysics Data System (ADS)

    Shubha, L. N.; Madhusudana Rao, P.

    2016-06-01

    The polyaniline/copper oxide (PANI/CuO) nanocomposite was prepared by mixing solutions of polyaniline and copper oxide nanoparticles in dimethyl sulfoxide (DMSO). The synthesized polymer nanocomposites were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectroscopy. The characteristic peaks in XRD and UV-visible spectra confirmed the presence of CuO in the polymer structure. SEM images indicated morphological changes in the composite matrix as compared to the pristine PANI. The DC conductivity measurements were performed using two-probe method for various temperatures. AC conductivity and dielectric response of the composites were investigated in the frequency range of 102-106Hz using LCR meter. Dielectric permittivity ɛ‧(w) and dielectric loss factor ɛ‧‧(w) were investigated. It was observed that ɛ‧(w) and ɛ‧‧(w) decrease with increase in frequency at all temperatures. At a particular frequency it is observed that both ɛ‧(w) and ɛ‧‧(w) increase with increase in temperature. It was also observed that AC conductivity increased with increase in frequency and temperature.

  3. AC conductivity studies of Fe doped TiO2 nanotubes

    NASA Astrophysics Data System (ADS)

    Vijayan, P. P.; Thomas, M.; George, K. C.

    2015-02-01

    Fe-doped TiO2 nanotubes are prepared by the combination of sol-gel process with hydrothermal treatment. The morphology and crystalline structure of TiO2 nanotubes are characterized by transmission electron microscopy (TEM), X-ray diffraction respectively (XRD). Fe doping induces a structural transformation from anatase to rutile. The temperature dependence of the ac electrical conductivity is investigated in the temperature range 303-413 K. Positive temperature coefficient of resistance is observed in the Fe doped TiO2 nanotubes. PL spectrum shows the presence of oxygen vacancies and self trapped excitons in Fe doped TiO2 nanotubes and undoped samples.

  4. AC conductivity scaling behavior in grain and grain boundary response regime of fast lithium ionic conductors

    NASA Astrophysics Data System (ADS)

    Mariappan, C. R.

    2014-05-01

    AC conductivity spectra of Li-analogues NASICON-type Li1.5Al0.5Ge1.5P3O12 (LAGP), Li-Al-Ti-P-O (LATP) glass-ceramics and garnet-type Li7La2Ta2O13 (LLTO) ceramic are analyzed by universal power law and Summerfield scaling approaches. The activation energies and pre-exponential factors of total and grain conductivities are following the Meyer-Neldel (M-N) rule for NASICON-type materials. However, the garnet-type LLTO material deviates from the M-N rule line of NASICON-type materials. The frequency- and temperature-dependent conductivity spectra of LAGP and LLTO are superimposed by Summerfield scaling. The scaled conductivity curves of LATP are not superimposed at the grain boundary response region. The superimposed conductivity curves are observed at cross-over frequencies of grain boundary response region for LATP by incorporating the exp ( {{{ - (EAt - EAg )} {{{ - (EAt - EAg )} {kT}}} ) factor along with Summerfield scaling factors on the frequency axis, where EAt and EAg are the activation energies of total and grain conductivities, respectively.

  5. Synthesis, Spectroscopic, ac Conductivity and Thermal Studies on Co(III) Acetylacetonate-Iodine Complex

    NASA Astrophysics Data System (ADS)

    Hashem, H. A.; Refat, M. S.

    A spectrophotometric study of 1:1 donor-acceptor complex, cobalt (III) acetylacetonate (donor) and iodine (σ-acceptor) has been preformed. The equilibrium constants, (K) and the absorpitivity (ɛ) for the formation of the iodine complex have been calculated. The predicted structure of the solid triiodide charge-transfer complex reported in this study is further supported by thermal, far and mid infrared spectroscopic measurements. Electron transfer from Co (acac = 2, 4-pentanedionate)3 to iodine leads to the formation of an organic semiconductor with the formula of [Co(acac)3]_2 I+. I3-. The kinetic parameters (nonisothermal method) for their decomposition have been evaluated by graphical methods using the equations of Freeman-Carroll (FC), Horowitz-Metzger (HM) and Coats-Redfern (CR). The ac conductivity and dielectric properties of [Co(acac)3]_2 I+. I3- have been measured over the frequency 50-106 Hz at temperature 298 K.

  6. Phonon effects on the current noise spectra and the ac conductance of a single molecular junction.

    PubMed

    Ding, Guo-Hui; Dong, Bing

    2014-07-30

    By using nonequilibrium Green's functions and the equation of motion method, we formulate a self-consistent field theory for the electron transport through a single-molecule junction (SMJ) coupled with a vibrational mode. We show that the nonequilibrium dynamics of the phonons in a strong electron-phonon coupling regime can be taken into account appropriately in this self-consistent perturbation theory, and the self-energy of the phonons is connected with the current fluctuations in the molecular junction. We calculate the finite-frequency nonsymmetrized noise spectra and the ac conductance, which reveal a wealth of inelastic electron tunneling characteristics on the absorption and emission properties of this SMJ. In the presence of a finite bias voltage and the electron tunneling current, the vibration mode of the molecular junction is heated and driven to an unequilibrated state. The influences of unequilibrated phonons on the current and the noise spectra are investigated.

  7. Phonon effects on the current noise spectra and the ac conductance of a single molecular junction

    NASA Astrophysics Data System (ADS)

    Ding, Guo-Hui; Dong, Bing

    2014-07-01

    By using nonequilibrium Green’s functions and the equation of motion method, we formulate a self-consistent field theory for the electron transport through a single-molecule junction (SMJ) coupled with a vibrational mode. We show that the nonequilibrium dynamics of the phonons in a strong electron-phonon coupling regime can be taken into account appropriately in this self-consistent perturbation theory, and the self-energy of the phonons is connected with the current fluctuations in the molecular junction. We calculate the finite-frequency nonsymmetrized noise spectra and the ac conductance, which reveal a wealth of inelastic electron tunneling characteristics on the absorption and emission properties of this SMJ. In the presence of a finite bias voltage and the electron tunneling current, the vibration mode of the molecular junction is heated and driven to an unequilibrated state. The influences of unequilibrated phonons on the current and the noise spectra are investigated.

  8. Ionic ac and dc conductivities of NaCrP2O7 compound

    NASA Astrophysics Data System (ADS)

    Sassi, M.; Oueslati, A.; Gargouri, M.

    2015-05-01

    The NaCrP2O7 compound was prepared by the solid-state reaction method. The formation of a single-phase material was confirmed by the X-ray diffraction studies and found to be a monoclinic system. The electrical properties of this compound have been measured in the temperature range from 523 to 673 K and the frequency range from 209 Hz to 5 MHz. The Nyquist plots are well fitted to an equivalent circuit consisting of a series of combination of grains and grain boundary elements. The ac conductivity of NaCrP2O7 has been analyzed as a function of temperature and frequency. The scaling behavior of the imaginary part of the complex modulus suggests that the relaxation describes the same mechanism at various temperatures. The conductivity and modulus formalisms provide nearly the same activation energies for electrical relaxation of mobile ions suggesting that the ion transport is probably due to a hopping mechanism dominated by the motion of the monovalent ions Na+ along tunnels presented in the structure of the investigated material.

  9. AC conductivity and dielectric relaxation of tris(N,N-dimethylanilinium) hexabromidostannate(IV) bromide: (C8H12N)3SnBr6.Br

    NASA Astrophysics Data System (ADS)

    Chouaib, H.; Kamoun, S.

    2015-10-01

    The X-ray powder analysis, thermogravimetric analysis, differential scanning calorimetry analysis and complex impedance spectroscopic data have been carried out on (C8H12N)3SnBr6.Br compound. The results show that this compound exhibits a phase transition at (T=365±2 K) which has been characterized by differential scanning calorimetry (DSC), AC conductivity and dielectric measurements. The AC conductivity, the modulus analysis, the dielectric constants and the polarizability have been studied using impedance in the temperature range from 334 K to 383 K and in the frequency range between 20 Hz and 2 MHz. The temperature dependence of DC conductivity follows the Arrhenius law. Moreover, the frequency dependence of conductivity follows Jonscher's dynamical law with the relation: σ(ω , T) =σDC + B(T)ω s(T) . Relaxation peaks can be observed in the complex modulus analysis and after a transformation of the complex permittivity ε* to the complex polarizability α*.

  10. Anomalous dielectric and AC conductivity behavior of the nanocrystalline Ni-Cu ferrite synthesized via combustion method

    SciTech Connect

    Madhu, B. J.; Rashmi, B. N.; Banu, Arshiya; Seema, G. A.; Shruthi, B.; Jayanna, H. S.

    2013-02-05

    Nanocrystalline Ni-Cu ferrites (Ni{sub 0.5}Cu{sub 0.5}Fe{sub 2}O{sub 4}) were prepared using solution combustion method. The structure of the samples were studied with the X-ray diffraction (XRD) using Cu-K{sub {alpha}} radiation. Frequency and temperature dependence of dielectric and a.c. conductivity studies have been undertaken on the Ni-Cu nanoferrites in the frequency region 100Hz-5MHz. The dielectric constant ({epsilon} Prime ) is found to decrease initially with the frequency and finally reaching a constant value at higher frequencies. Observed trends in the dielectric constant are ascribed to the Maxwell-Wagner type interfacial polarization, which is in agreement with the Koop'fs phenomenological theory. The a.c. conductivity ({sigma}{sub ac}) is found to increase with an increase in the frequency from room temperature up to 300 Degree-Sign C. However, at a temperature of 400 Degree-Sign C, the a.c. conductivity is found to decrease with an increase in the frequency exhibiting an abnormal behavior. The electrical conduction mechanism in the present nano nickel-copper ferrite is found to be in accordance with the electron hopping model.

  11. Anomalous dielectric and AC conductivity behavior of the nanocrystalline Ni-Cu ferrite synthesized via combustion method

    NASA Astrophysics Data System (ADS)

    Madhu, B. J.; Rashmi, B. N.; Banu, Arshiya; Seema, G. A.; Shruthi, B.; Jayanna, H. S.

    2013-02-01

    Nanocrystalline Ni-Cu ferrites (Ni0.5Cu0.5Fe2O4) were prepared using solution combustion method. The structure of the samples were studied with the X-ray diffraction (XRD) using Cu-Kα radiation. Frequency and temperature dependence of dielectric and a.c. conductivity studies have been undertaken on the Ni-Cu nanoferrites in the frequency region 100Hz-5MHz. The dielectric constant (ɛ') is found to decrease initially with the frequency and finally reaching a constant value at higher frequencies. Observed trends in the dielectric constant are ascribed to the Maxwell-Wagner type interfacial polarization, which is in agreement with the Koop'fs phenomenological theory. The a.c. conductivityac) is found to increase with an increase in the frequency from room temperature up to 300 °C. However, at a temperature of 400 °C, the a.c. conductivity is found to decrease with an increase in the frequency exhibiting an abnormal behavior. The electrical conduction mechanism in the present nano nickel-copper ferrite is found to be in accordance with the electron hopping model.

  12. A.c. conductivity and dielectric properties of LiNi 3/5Cu 2/5VO 4 ceramics

    NASA Astrophysics Data System (ADS)

    Ram, Moti

    2010-03-01

    The LiNi 3/5Cu 2/5VO 4 was synthesized using solution-based chemical method whose dielectric and a.c. conductivity properties were investigated using complex impedance spectroscopy (CIS) technique. Variation of dielectric constant ( εr) as a function of frequency at different temperatures indicates low frequency dispersion. A.c conductivity analysis indicates that electrical conduction in the material is a thermally activated process. Frequency dependence of a.c. conductivity at different temperatures obeys Jonscher's universal law: σ ac= σ dc+ A( ω) n.

  13. AC Hopping Conductance in Nanocomposite Films with Ferromagnetic Alloy Nanoparticles in a PbZrTiO3 Matrix

    NASA Astrophysics Data System (ADS)

    Koltunowicz, T. N.; Zukowski, P.; Boiko, O.; Saad, A.; Fedotova, J. A.; Fedotov, A. K.; Larkin, A. V.; Kasiuk, J.

    2015-07-01

    In this work, the temperature and frequency dependences of the real part of the admittance [ σ( f, T)] of annealed nanocomposite films containing Co45 Fe45Zr10-based nanoparticles covered with native oxides and embedded in a doped PbZrTiO3 ferroelectric matrix were studied. The nanocomposites studied were deposited by ion sputtering a complex target in a mixed Ar/O2 atmosphere followed by a 15-min annealing process (with steps of 25 K) in air in the temperature range of 398 K ≤ T a ≤ 573 K. The σ( f, T) of the annealed samples was measured in the temperature range of 77 K < T p < 373 K at frequencies of 50 Hz < f < 1 MHz. The observed σ( f, T) dependences confirmed that the annealed samples displayed the effects of negative capacitance over the whole frequency and temperature ranges studied because of the pronounced oxidation of the nanoparticles. The σ( f, T) dependences obtained are described using an earlier-developed AC hopping conductance model. Comparisons between experimental and simulation results allow the model parameters to be estimated, such as the activation energies of the hopping conductance and the lifetimes of the electrons in the nanoparticles.

  14. 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.

  15. The change in dielectric constant, AC conductivity and optical band gaps of polymer electrolyte film: Gamma irradiation

    SciTech Connect

    Raghu, S. Subramanya, K. Sharanappa, C. Mini, V. Archana, K. Sanjeev, Ganesh Devendrappa, H.

    2014-04-24

    The effects of gamma (γ) irradiation on dielectric and optical properties of polymer electrolyte film were investigated. The dielectric constant and ac conductivity increases with γ dose. Also optical band gap decreased from 4.23 to 3.78ev after irradiation. A large dependence of the polymer properties on the irradiation dose was noticed. This suggests that there is a possibility of improving polymer electrolyte properties on gamma irradiation.

  16. AC CONDUCTION PHENOMENON OF Li2O-WO3-B2O3 GLASSES DOPED WITH V2O5

    NASA Astrophysics Data System (ADS)

    Rao, Linganaboina Srinivasa; Veeraiah, Nalluri; Rao, Tumu Venkatappa

    2013-04-01

    The glass composition 40Li2O-5WO3-(55-x)B2O3: xV2O5 for x = 0.2, 0.4, 0.6 and 0.8 is chosen for the present study. The glass samples were synthesized by conventional melt-quenching technique. The dielectric properties such as constant (ɛ‧), loss (tan δ) and ac conductivityac) are carried out as a function of temperature (30-270°C) and frequency (102-105 Hz). The glass sample (at x = 0.6) exhibited highest ac conductivityac) and spreading factor (β) among all the samples. All glasses exhibited mixed conduction (both electronic and ionic) at high temperatures. The frequency exponent s denotes the ac conduction mechanism is associated with both QMT model (at low temperatures) and CBH model (at high temperatures).

  17. A.C. Conductivity of Bi2Cu0.1V0.9O5.35 Films for Fuel Cell Application

    NASA Astrophysics Data System (ADS)

    Nimat, R. K.; Lokare, S. A.; Pawar, S. H.

    2011-07-01

    The A.C. conductivity and dielectric properties of Bi2Cu0.1V0.9O5.35 thin films were studied as a function of frequency and temperature. The A.C. conductivity of Bi2Cu0.1V0.9O5.35 film increases with frequency. The low frequency region corresponds to the D.C. conductivity where the inter-well hopping responsible for D.C. conduction completely dominates over the intra-well hopping associated with pure A.C. conduction. Higher values of A.C. conductivity for films formed on alumina substrates predict their suitability for fuel cell application

  18. First experimental results from DC/DC and AC/DC plasma-based power transformers

    NASA Astrophysics Data System (ADS)

    McEvoy, Aaron; Gibson, William; Nebel, Richard

    2016-10-01

    A plasma-based power transformer has been built and operated in both DC/DC and AC/DC mode. The proprietary Tibbar Plasma Technologies, Inc. transformer design consists of two cylindrically symmetric helical primary electrodes surrounding a low temperature plasma within which a secondary axial current is generated. Initial experimental results have compared well with simulations and moderate conversion efficiencies have been observed. A new proprietary device is currently being constructed that will utilize 3-phase 480 VAC input to achieve higher conversion efficiency and output power. A description of the apparatus and several potential applications will be presented along with preliminary experimental data demonstrating the DC/DC and AC/DC conversion processes. Work performed under ARPA-E contract DE-AR0000677.

  19. AC magnetic field-assisted method to develop porous carbon nanotube/conducting polymer composites for application in thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Chuang, Chun-Yu; Yang, Shu-Chian; Chang, Su-Hua; Yang, Ta-I.

    2015-04-01

    Thermoelectric materials are very effective in converting waste heat sources into useful electricity. Researchers are continuing to develop new polymeric thermoelectric materials. The segregated-network carbon nanotube (CNT)- polymer composites are most promising. Thus, the goal of this study is to develop novel porous CNT -polymer composites with improved thermoelectric properties. The research efforts focused on modifying the surface of the CNT with magnetic nanoparticles so that heat was released when subjecting to an AC magnetic field. Subsequently, polymers covered on the surface of the CNT were crosslinked. The porous CNT -polymer composites can be obtained by removing the un-crosslinked polymers. Polydimethylsiloxane polymer was utilized to investigate the effect of porosity and electrical conductivity on the thermoelectric properties of the composites. This AC magnetic field-assisted method to develop porous carbon nanotube/polymer composites for application in thermoelectric materials is introduced for the first time. The advantage of this method is that the electrical conductivity of the composites was high since we can easily to manipulate the CNT to form a conducting path. Another advantage is that the high porosity significantly reduced the thermal conductivity of the composites. These two advantages enable us to realize the polymer composites for thermoelectric applications. We are confident that this research will open a new avenue for developing polymer thermoelectric materials.

  20. Development of the Exams Data Analysis Spreadsheet as a Tool to Help Instructors Conduct Customizable Analyses of Student ACS Exam Data

    ERIC Educational Resources Information Center

    Brandriet, Alexandra; Holme, Thomas

    2015-01-01

    The American Chemical Society Examinations Institute (ACS-EI) has recently developed the Exams Data Analysis Spread (EDAS) as a tool to help instructors conduct customizable analyses of their student data from ACS exams. The EDAS calculations allow instructors to analyze their students' performances both at the total score and individual item…

  1. ac conduction in disordered solids: Comparison of effective-medium and distributed-transition-rate-response models

    NASA Astrophysics Data System (ADS)

    MacDonald, J. Ross

    1994-04-01

    Dyre has proposed that in the low-temperature limit an effective medium approximation, termed the Bryksin equation here (the BEM), predicts a universal frequency dependence for the normalized small-signal ac frequency relaxation response of nonmetallic disordered solids. This response has been claimed to be practically identical to that found for an exponential distribution of transition rates (EDTR) in the particular limiting uniform-energy-barrier-distribution case, but comparison of the two responses has been inadequate so far. Although it is shown here that they can be well differentiated, the question of which or either is universal still requires further comparisons with experiment for its answer. A generalization of the limiting low-temperature BEM equation applicable for nonzero temperatures, the GBEM, is developed and used to evaluate the temperature and frequency ranges for which the BEM is still adequate. It is found that GBEM response can be well approximated by the important EDTR solution and leads to a frequency exponent with the same temperature dependence as the latter. An expression derived herein for the dc conductivity predicted by the GBEM involves 1/3 of the maximum thermal activation energy (i.e., the effective percolation energy), however, rather than the energy itself. Further, unlike the BEM, the GBEM predicts the presence of an intrinsic temperature-independent high-frequency-limiting conductivity whose magnitude is evaluated. The combination of conductive- and dielectric-system response, always experimentally present for a conductive system, is evaluated for the GBEM, and in the frequency range where the GBEM and BEM are indistinguishable it leads to frequency and temperature response remarkably similar to that observed for most disordered materials. Finally, it is suggested that Dyre's macroscopic simulations of the relaxation problem do not seem fully relevant to physical situations of interest and thus should not be taken to confirm

  2. Optical, electrical and ac conductivity measurements of nonlinear optical Dimethylaminomethylphthalimide doped with cadmium chloride single crystal for nano applications

    NASA Astrophysics Data System (ADS)

    Subramani, K.; Joseph, P. S.; Shankar, G.

    2013-07-01

    Single crystals of Dimethylaminomethylphthalimide cadmium chloride (DAMPCC) were grown by a slow evaporation technique. The unit cell parameters and crystal structure were measured by the powder X-ray diffraction analysis. The modes of vibrations of different molecular groups present in the DAMPCC crystal have been identified by FTIR spectral analysis. The UV-vis-NIR spectral analysis is used to study the optical behaviors like absorption and transmission properties of the crystal. The diffuse reflectance spectrum in absorption studies is calculated. The optical band gap of the DAMPCC crystal is calculated to be cut off wavelength 360 nm at photon energy 4.772 eV. The optical conductivity, electrical conductivity and ac conductivity are also calculated. Finally the nonlinear optics (NLO) property of DAMPCC crystal was confirmed by second harmonic generation (SHG) test using the Nd:YAG laser of fundamental wavelength 1064 nm.

  3. Anomalous three-dimensional bulk ac conduction within the Kondo gap of SmB6 single crystals

    NASA Astrophysics Data System (ADS)

    Laurita, N. J.; Morris, C. M.; Koohpayeh, S. M.; Rosa, P. F. S.; Phelan, W. A.; Fisk, Z.; McQueen, T. M.; Armitage, N. P.

    2016-10-01

    The Kondo insulator SmB6 has long been known to display anomalous transport behavior at low temperatures, T <5 K. In this temperatures range, a plateau is observed in the dc resistivity, contrary to the exponential divergence expected for a gapped system. Recent theoretical calculations suggest that SmB6 may be the first topological Kondo insulator (TKI) and propose that the residual conductivity is due to topological surface states which reside within the Kondo gap. Since the TKI prediction many experiments have claimed to observe high mobility surface states within a perfectly insulating hybridization gap. Here, we investigate the low energy optical conductivity within the hybridization gap of single crystals of SmB6 via time domain terahertz spectroscopy. Samples grown by both optical floating zone and aluminum flux methods are investigated to probe for differences originating from sample growth techniques. We find that both samples display significant three-dimensional bulk conduction originating within the Kondo gap. Although SmB6 may be a bulk dc insulator, it shows significant bulk ac conduction that is many orders of magnitude larger than any known impurity band conduction. The nature of these in-gap states and their coupling with the low energy spin excitons of SmB6 is discussed. Additionally, the well-defined conduction path geometry of our optical experiments allows us to show that any surface states, which lie below our detection threshold if present, must have a sheet resistance of R /square≥ 1000 Ω .

  4. Dielectric and ac conductivity studies of ZnO/Eu3+: Titanosilicate matrix

    NASA Astrophysics Data System (ADS)

    Arun Kumar, K. V.; Sunil, Thomas; Ann Mary, K. A.; Cyriac, Joseph; Biju, P. R.; Unnikrishnan, N. V.

    2014-01-01

    ZnO nanoparticles /Eu3+ doped SiO2-TiO2 matrices were synthesized through sol-gel route. Structural and dielectric properties of ZnO nanocrystallites co-doped with Eu3+ in SiO2-TiO2 matrices were presented. The HRTEM and XRD measurements confirm the presence of ZnO nanocrystallites. The dielectric and electrical conductivity studies of the samples are completed for a frequency of 100 Hz to 2 MHz. The conductivity variation with the ZnO content in the Eu3+ doped SiO2-TiO2 system were explained by correlating the presence of ionic contribution to the electrical conductivity process. From the frequency dependence of dielectric constant and conductivity, the Cole-Cole parameters and power law parameters were evaluated. The dielectric relaxation phenomena were investigated using the dielectric moduli formulation.

  5. Conducting Dental Examinations for Visually Impaired Children: Methods and Results.

    ERIC Educational Resources Information Center

    Mallatt, Mark E.; Palenik, Charles John

    1990-01-01

    Basic dental examinations were conducted on 35 visually impaired students aged 5 to 16 years in a state-supported residential school, and results were compared with national and state findings. Oral hygiene and gingival inflammation levels were found to be suboptimal but not atypical. (Author/PB)

  6. AC conductivity of (FeCoZr)x(PZT)(100-x) nanocomposites produced in vacuum chamber

    NASA Astrophysics Data System (ADS)

    Boiko, Oleksandr; Bondariev, Vitalii; Czarnacka, Karolina

    2015-09-01

    In this work, the temperature and frequency dependences of conductivity σ and Arrhenius plots of annealed nanocomposite films containing Fe45Co45Zr10 - based nanoparticles embedded in a doped PbZrTiO3 ferroelectric matrix were studied. The nanocomposites studied were deposited by sputtering with use of argon and oxygen ions in a vacuum chamber. Tested samples were followed by a 15-min annealing process in air in the temperature range of 398 K <= Ta <= 748 K with steps of 25 K. The σ(f,T) dependences of nanocomposite samples was measured in ambient temperature range of 77 K < Tp < 373 K at frequencies of 50 Hz < f < 1MHz. It was established that nanocomposite sample with metallic phase content x = 55.6 at.% demonstrates strong temperature and frequency dependences, which is typical for a percolation systems. Type of conduction in such nanostructure is defined as dielectric, which may be related with the additional oxidation of metallic nanoparticles during the annealing process. For the tested sample with x = 88.4 at.%. we observe metallic type of conduction, when metallic nanoparticles form a permanent conductive channels in dielectric matrix.

  7. AC conductivity and electrochemical studies of PVA/PEG based polymer blend electrolyte films

    NASA Astrophysics Data System (ADS)

    Polu, Anji Reddy; Kumar, Ranveer; Dehariya, Harsha

    2012-06-01

    Polymer blend electrolyte films based on Polyvinyl alcohol(PVA)/Poly(ethylene glycol)(PEG) and magnesium nitrate (Mg(NO3)2) were prepared by solution casting technique. Conductivity in the temperature range 303-373 K and transference number measurements have been employed to investigate the charge transport in this polymer blend electrolyte system. The highest conductivity is found to be 9.63 × 10-5 S/cm at 30°C for sample with 30 weight percent of Mg(NO3)2 in PVA/PEG blend matrix. Transport number data shows that the charge transport in this polymer electrolyte system is predominantly due to ions. Using this electrolyte, an electrochemical cell with configuration Mg/(PVA+PEG+Mg(NO3)2)/(I2+C+electrolyte) was fabricated and its discharge characteristics profile has been studied.

  8. Effects of Luttinger leads on the AC conductance of a quantum dot

    NASA Astrophysics Data System (ADS)

    Yang, Kai-Hua; Qin, Chang-Dong; Wang, Huai-Yu; Liu, Kai-Di

    2017-04-01

    We investigate the joint effects of the intralead electron interaction and an external alternating gate voltage on the transport of a quantum dot coupled to two Luttinger liquid leads in the Kondo regime. We find the transferring between two Kondo physics mechanics by investigation of differential conductance. For very weak intralead interaction, the satellite and main Kondo resonant peaks appear in the differential conductance. For moderately strong intralead interaction, all the peaks disappear and evolve into dips, which signifies that a photon-assisted single-channel Kondo (1CK) physics turns into two-channel Kondo (2CK) physics. The 1CK and 2CK mechanisms can coexist within a region of the intralead interaction parameter. The 1CK physics transits to the 2CK one gradually, not suddenly. In the limit of strong interaction, all dips disappear. When the bias voltage is small, there is no photon exchange between the quantum dot and alternative field, and the differential conductance scales as a power law both in bias voltage and in temperature. As the field becomes stronger, the quantum dot will emit and absorb photons.

  9. Alteration of Tephra Conductivity Resulting From Secondary Pyroclast Disaggregation

    NASA Astrophysics Data System (ADS)

    Genareau, K. D.; Farley, A. W.

    2014-12-01

    In addition to influencing the electrical conductivity of volcanic ash, leachates bound to ash grain surfaces may pose significant hazards to water quality through the contribution of sulfates, fluoride, metals, and acidic compounds to local water supplies by either direct ash fallout or incorporation into precipitation runoff. In regions of active volcanism, remobilization of pyroclastic units may be a regular occurrence due to landslides or lahars, but the resultant effects of secondary disaggregation of pyroclasts have not been examined. Laboratory analyses of tephras from several eruptive centers have revealed variations in the pH, conductivity, and total dissolved solid (TDS) concentration of water-soluble compounds as a result of pyroclast disaggregation. Analyses were conducted using the standardized protocols for ash leachate analysis. TDS, conductivity, and pH were then measured and the tephra samples were allowed to air dry before being retested using identical methods. When pyroclast disaggregation was not performed, results show a progressive decrease in water conductivity, acidity, and TDS concentration following each stage of sonication. However, when an additional step of clast disaggregation (through crushing and grinding of samples) preceded the sonication step, water samples showed increases in measured properties. Mass spectroscopic analyses of water samples are in progress and results will be presented. These results indicate that secondary comminution of pyroclastic deposits will release water-soluble components from the pyroclast interior that may result in a renewed series of environmental hazards many years after the initial eruptive event. Break up of pyroclasts during transport in landslides or lahars (or even during cleanup efforts) will not only alter the size distribution of the deposit, but will also release metals, sulfates, and fluoride from the tephra interiors, altering the chemical and electrical properties of the tephra. This

  10. Crystal structure, NMR study, dielectric relaxation and AC conductivity of a new compound [Cd3(SCN)2Br6(C2H9N2)2]n

    NASA Astrophysics Data System (ADS)

    Saidi, K.; Kamoun, S.; Ayedi, H. Ferid; Arous, M.

    2013-11-01

    The crystal structure, the 13C NMR spectroscopy and the complex impedance have been carried out on [Cd3(SCN)2Br6(C2H9N2)2]n. Crystal structure shows a 2D polymeric network built up of two crystallographically independent cadmium atoms with two different octahedral coordinations. This compound exhibits a phase transition at (T=355±2 K) which has been characterized by differential scanning calorimetry (DSC), X-rays powder diffraction, AC conductivity and dielectric measurements. Examination of 13C CP/MAS line shapes shows indirect spin-spin coupling (14N and 13C) with a dipolar coupling constant of 1339 Hz. The AC conductivity of this compound has been carried out in the temperature range 325-376 K and the frequency range from 10-2 Hz to 10 MHz. The impedance data were well fitted to two equivalent electrical circuits. The results of the modulus study reveal the presence of two distinct relaxation processes. One, at low frequency side, is thermally activated due to the ionic conduction of the crystal and the other, at higher frequency side, gradually disappears when temperature reaches 355 K which is attributed to the localized dipoles in the crystal. Moreover, the temperature dependence of DC-conductivity in both phases follows the Arrhenius law and the frequency dependence of σ(ω,T) follows Jonscher's universal law. The near values of activation energies obtained from the conductivity data and impedance confirm that the transport is through the ion hopping mechanism.

  11. Estimation of Density of Localized States in Amorphous Se80Te20 and Se80Te10M10 (M = Cd, In, Sb) Alloys Using AC Conductivity Measurements

    NASA Astrophysics Data System (ADS)

    Chandel, N.; Mehta, N.; Kumar, A.

    2015-08-01

    The ac conductivity of amorphous Se80Te20 (a-Se80Te20) and amorphous Se80Te10M10 (a-Se80Te10M10) alloys has been measured as a function of temperature and frequency in a low-temperature regime. An analysis of the experimental data confirms that ac conductivity is reasonably well interpreted by the Austin-Mott model. The density of localized states was determined in the low-temperature region from 201 K to 280 K. Possible explanations of "metal-induced effects" on the conduction mechanism of a-Se80Te20 alloy are discussed.

  12. Iatrogenic hypernatremia in hemodialysis patients: A result erroneous online conductivity monitor and conductivity meter reading.

    PubMed

    Obialo, Chamberlain I; John, Smitha; Bashir, Khalid

    2017-03-08

    Hyponatremia is common in chronic kidney disease and in end stage kidney disease (ESKD) but hypernatremia is infrequent in ESKD. The incidence of hypernatremia is higher in ambulatory peritoneal dialysis (PD) than in hemodialysis (HD) patients. In PD patients it is often a result of excessive ultrafiltration but in HD it is often a result of dialysate composition errors. Dialysate composition errors can inadvertently cause either hyponatremia or hypernatremia. We present two cases of symptomatic hypernatremia which manifested as increased thirst, excessive weight gain and worsening hypertension in HD patients. The hypernatremia was caused by a combination of errors in online conductivity reading and a faulty hand held conductivity meter. Symptoms were relieved in both patients after replacement of the dialysis machine.

  13. Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results

    SciTech Connect

    Chandler, K.; Eudy, L.

    2007-03-01

    This report provides an evaluation of three prototype fuel cell-powered transit buses operating at AC Transit in Oakland, California, and six baseline diesel buses similar in design to the fuel cell buses.

  14. Ac conductivity studies of solution combustion synthesized nanocrystalline Li2MgZrO4 material

    NASA Astrophysics Data System (ADS)

    Cheruku, Rajesh; Vijayan, Lakshmi; Govindaraj, G.

    2012-06-01

    A phase-pure nanocrystalline Li2MgZrO4 material is synthesized by solution combustion synthesis. In this study citric acid is used as fuel and pH of the homogenous solution is maintained. The material is crystallized in a cubic rock-salt structure of space group Fm⃞3m. TEM analysis revealed that the material is formed as nano-crystallites. The structural characterization is accomplished through X-ray diffraction, thermogravimetry, differential thermal analysis, transmission electron microscopy and electrical characterization is done through impedance spectroscopy and the results are reported.

  15. A single-shot spatial chirp method for measuring initial AC conductivity evolution of femtosecond laser pulse excited warm dense matter

    SciTech Connect

    Chen, Z.; Hering, P.; Brown, S. B.; Curry, C.; Tsui, Y. Y.; Glenzer, S. H.

    2016-09-19

    To study the rapid evolution of AC conductivity from ultrafast laser excited warm dense matter (WDM), a spatial chirp single-shot method is developed utilizing a crossing angle pump-probe configuration. The pump beam is shaped individually in two spatial dimensions so that it can provide both sufficient laser intensity to excite the material to warm dense matter state and a uniform time window of up to 1 ps with sub-100 fs FWHM temporal resolution. Here, temporal evolution of AC conductivity in laser excited warm dense gold was also measured.

  16. A single-shot spatial chirp method for measuring initial AC conductivity evolution of femtosecond laser pulse excited warm dense matter.

    PubMed

    Chen, Z; Hering, P; Brown, S B; Curry, C; Tsui, Y Y; Glenzer, S H

    2016-11-01

    To study the rapid evolution of AC conductivity from ultrafast laser excited warm dense matter (WDM), a spatial chirp single-shot method is developed utilizing a crossing angle pump-probe configuration. The pump beam is shaped individually in two spatial dimensions so that it can provide both sufficient laser intensity to excite the material to warm dense matter state and a uniform time window of up to 1 ps with sub-100 fs FWHM temporal resolution. Temporal evolution of AC conductivity in laser excited warm dense gold was also measured.

  17. Nonlinear Fourier analysis for discontinuous conductivities: Computational results

    SciTech Connect

    Astala, Kari; Päivärinta, Lassi; Reyes, Juan Manuel; Siltanen, Samuli

    2014-11-01

    Two reconstruction methods of Electrical Impedance Tomography (EIT) are numerically compared for nonsmooth conductivities in the plane based on the use of complex geometrical optics (CGO) solutions to D-bar equations involving the global uniqueness proofs for Calderón problem exposed in Nachman (1996) [43] and Astala and Päivärinta (2006) [6]: the Astala–Päivärinta theory-based low-pass transport matrix method implemented in Astala et al. (2011) [3] and the shortcut method which considers ingredients of both theories. The latter method is formally similar to the Nachman theory-based regularized EIT reconstruction algorithm studied in Knudsen et al. (2009) [34] and several references from there. New numerical results are presented using parallel computation with size parameters larger than ever, leading mainly to two conclusions as follows. First, both methods can approximate piecewise constant conductivities better and better as the cutoff frequency increases, and there seems to be a Gibbs-like phenomenon producing ringing artifacts. Second, the transport matrix method loses accuracy away from a (freely chosen) pivot point located outside of the object to be studied, whereas the shortcut method produces reconstructions with more uniform quality.

  18. Nonlinear Fourier analysis for discontinuous conductivities: Computational results

    NASA Astrophysics Data System (ADS)

    Astala, Kari; Päivärinta, Lassi; Reyes, Juan Manuel; Siltanen, Samuli

    2014-11-01

    Two reconstruction methods of Electrical Impedance Tomography (EIT) are numerically compared for nonsmooth conductivities in the plane based on the use of complex geometrical optics (CGO) solutions to D-bar equations involving the global uniqueness proofs for Calderón problem exposed in Nachman (1996) [43] and Astala and Päivärinta (2006) [6]: the Astala-Päivärinta theory-based low-pass transport matrix method implemented in Astala et al. (2011) [3] and the shortcut method which considers ingredients of both theories. The latter method is formally similar to the Nachman theory-based regularized EIT reconstruction algorithm studied in Knudsen et al. (2009) [34] and several references from there. New numerical results are presented using parallel computation with size parameters larger than ever, leading mainly to two conclusions as follows. First, both methods can approximate piecewise constant conductivities better and better as the cutoff frequency increases, and there seems to be a Gibbs-like phenomenon producing ringing artifacts. Second, the transport matrix method loses accuracy away from a (freely chosen) pivot point located outside of the object to be studied, whereas the shortcut method produces reconstructions with more uniform quality.

  19. AC impedance analysis of ionic and electronic conductivities in electrode mixture layers for an all-solid-state lithium-ion battery

    NASA Astrophysics Data System (ADS)

    Siroma, Zyun; Sato, Tomohiro; Takeuchi, Tomonari; Nagai, Ryo; Ota, Akira; Ioroi, Tsutomu

    2016-06-01

    The ionic and electronic effective conductivities of an electrode mixture layers for all-solid-state lithium-ion batteries containing Li2Ssbnd P2S5 as a solid electrolyte were investigated by AC impedance measurements and analysis using a transmission-line model (TLM). Samples containing graphite (graphite electrodes) or LiNi0.5Co0.2Mn0.3O2 (NCM electrodes) as the active material were measured under a "substrate | sample | bulk electrolyte | sample | substrate" configuration (ion-electron connection) and a "substrate | sample | substrate" configuration (electron-electron connection). Theoretically, if the electronic resistance is negligibly small, which is the case with our graphite electrodes, measurement with the ion-electron connection should be effective for evaluating ionic conductivity. However, if the electronic resistance is comparable to the ionic resistance, which is the case with our NCM electrodes, the results with the ion-electron connection may contain some inherent inaccuracy. In this report, we theoretically and practically demonstrate the advantage of analyzing the results with the electron-electron connection, which gives both the ionic and electronic conductivities. The similarity of the behavior of ionic conductivity with the graphite and NCM electrodes confirms the reliability of this analysis.

  20. Normal-Conducting RF Structure Test Facilities and Results

    SciTech Connect

    Adolphsen, C

    2003-10-06

    The designs for a next-generation linear collider based on normal-conducting rf structures require operation at gradients much higher than those in existing linacs. For the NLC/GLC 11.4-GHz structures, the design unloaded gradient is 65 MV/m, which is about four times that of the 2.9-GHz SLAC Linac. For the CLIC 30-GHz structures, a substantially higher gradient, 170 MV/m, is required. Both the NLC/GLC and CLIC groups are aggressively pursuing programs to develop structures that operate reliably at these gradients and also have acceptable efficiencies and transverse wakefields. Much progress has been made in the past few years, and this paper reviews the programs, test facilities and results from this research.

  1. Synthesis, crystal structure, NMR study and AC conductivity of [(C3H7)4N]2Cd2ClF5 compound

    NASA Astrophysics Data System (ADS)

    Hajji, Rachid; Oueslati, Abderrazak; Body, Monique; Hlel, Faouzi

    2015-08-01

    The [(C3H7)4N]2Cd2ClF5 compound was crystallized in the triclinic system with space group P1. The crystal structure consists of organic-inorganic layers, stacked along direction. The organic part consists of two cations types. The inorganic layer is made up of Cd2ClF5 dimmers composed of two in-equivalent irregular tetrahedra sharing one edge (Cl-F). The MAS NMR spectra showed two, three and five isotropic resonances relative to 111Cd, 13C and 19F nuclei, respectively. DSC measurement disclosed a phase transition at around 380 K. The impedance spectroscopy and AC electrical conductivity measurements of our compound were taken from 209 Hz to 5 MHz over the temperature range of 350-381 K. Nyquist plots ( Z″ vs Z') show semicircle arcs at different temperatures, and an electrical equivalent circuit has been proposed to explain the impedance results. The circuits consist of the parallel combination of bulk resistance ( R), capacitance ( C) and fractal capacitance (CPE). The conductivity σ p follows the Arrhenius relation. The near value of activation energies obtained from the conductivity data and circuit equivalent confirms that the transport is through hopping mechanism. The analysis of the experimental data shows that the reorientation motion of [N(C3H7)4]+ cations and/or [Cd2ClF5]2- anions is probably responsible for the observed conductivity.

  2. Influence of n-type nickel ferrite in enhancing the AC conductivity of optimized polyaniline-nickel ferrite nanocomposite

    NASA Astrophysics Data System (ADS)

    Megha, R.; Ravikiran, Y. T.; Vijaya Kumari, S. C.; Thomas, S.

    2017-04-01

    In the present work, n-type nickel ferrite (NF) particles prepared by sol gel autocombustion method were used to synthesize optimized polyaniline-nickel ferrite (PANI-NF) nanocomposite by in situ polymerization method. Then, NF, PANI and the composite were structurally characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Improved π-electron delocalization in PANI-NF composite as compared to that in PANI was confirmed from FTIR analysis. Interfacial interaction between PANI and NF was confirmed from XRD studies. Highly agglomerated, more densely packed particles of the composite facilitating easier charge transport were confirmed from SEM image. Transmission electron microscopy (TEM) image was analysed to calculate accurate average particle size of the composite by fitting the data to log-normal distribution function. Crystalline nature of the composite was confirmed from selected area electron diffraction (SAED) analysis. Remarkable increase in AC conductivity of the PANI-NF composite as compared to that of PANI due mainly to the formation of interfacial heterojunction barrier between p-type PANI and n-type NF was confirmed experimentally and well supported theoretically by calculating binding energy, hopping distance and density of states at Fermi level as per correlated barrier hopping (CBH) model.

  3. AC conductivity and its scaling behavior in MgO-Li2O-B2O3-Bi2O3 glasses

    NASA Astrophysics Data System (ADS)

    Purnima, M.; Bale, Shashidhar; Samee, M. A.; Ahmmad, Shaik Kareem; Rahman, Syed

    2013-02-01

    In the present work, the compositional dependence of density, refractive index and glass transition temperature of xMgO-(25-x)Li2O-50B2O3-25Bi2O3 glasses is studied. Impedance spectroscopy technique is employed on these samples and the data are analyzed using Cole-Cole type impedance response function. The AC conductivity behavior of the present glasses has been investigated in the frequency range from 100 Hz to 1 MHz and as a function of temperature the measured AC data are analyzed using the Jonscher’s universal power law to explain the observed dispersive behavior of the electrical conductivity. The temperature and composition dependence scaling behavior in the AC conductivity are satisfactorily explained by scaling the AC conductivity σ‧(ω) by hopping frequency ωp. The frequency response of dielectric constant ɛ‧ and dielectric loss tanδ as a function of temperature were studied. The tanδ peak shifts to higher frequency with increasing temperature, indicating dipolar relaxation character of dielectric loss in the present glasses.

  4. Impedance and AC conductivity study of nano crystalline, fine grained multiferroic bismuth ferrite (BiFeO3), synthesized by microwave sintering

    NASA Astrophysics Data System (ADS)

    Kolte, Jayant; Salame, Paresh H.; Daryapurkar, A. S.; Gopalan, P.

    2015-09-01

    In this paper, major reduction in sintering time,temperautre and significant improvement over final density of sitnered sample is reported for the microwave sintered nanocrystalline BiFeO3 (BFO) ceramic. Also, different sintering time and temperatures have been used to tailor the grain size and the final density of the resulting BFO ceramics synthesized from phase pure BFO nanoparticles ( d ¯ ≈ 10 n m ). Microwave sintering resulted in reducing the sintering time substantially (by 1h), and has resulted in submicron sized grains and high resistivity ˜1.8 GΩ-cm. The AC conductivity is seen to follow the Jonscher's power law behavior, suggesting correlated barrier hopping (CBH) mechanism in the sample. The role of oxygen vacancies at high temperature, due to volatility of bismuth, in dielectric and conductivity behavior is also discussed. Further, the sample displayed dielectric anomaly near magnetic transition temperature (˜180 °C) indicating bearing of magnetic moments on the dielectric properties. Using Impedance Spectroscopy (IS) we have established, the electrical heterogeneity of the ceramic BFO reavealing semiconducting nature of grains and insulating nature of grain boundary. This, formation of network of insulating grain boundaries and semiconducting grains could lead to formation of internal barrier layer capacitance (IBLC) leading to high dielectric constant in microwave sintered BFO.

  5. Mutation Glu82Lys in lamin A/C gene is associated with cardiomyopathy and conduction defect

    SciTech Connect

    Wang Hu; Wang Jizheng; Zheng Weiyue; Wang Xiaojian; Wang Shuxia; Song Lei; Zou Yubao; Yao Yan; Hui Rutai . E-mail: huirutai@sglab.org

    2006-05-26

    Dilated cardiomyopathy is a form of heart muscle disease characterized by impaired systolic function and ventricular dilation. The mutations in lamin A/C gene have been linked to dilated cardiomyopathy. We screened genetic mutations in a large Chinese family of 50 members including members with dilated cardiomyopathy and found a Glu82Lys substitution mutation in the rod domain of the lamin A/C protein in eight family members, three of them have been diagnosed as dilated cardiomyopathy, one presented with heart dilation. The pathogenic mechanism of lamin A/C gene defect is poorly understood. Glu82Lys mutated lamin A/C and wild type protein was transfected into HEK293 cells. The mutated protein was not properly localized at the inner nuclear membrane and the emerin protein, which interacts with lamin A/C, was also aberrantly distributed. The nuclear membrane structure was disrupted and heterochromatin was aggregated aberrantly in the nucleus of the HEK293 cells stably transfected with mutated lamin A/C gene as determined by transmission electron microscopy.

  6. Determining Conductivity by Boundary Measurements: Some Numerical Results

    DTIC Science & Technology

    1988-05-01

    continuous, then -:Let B, ~ - 71iAl. If, 71i and 7y2 are Lipschitz continuous, and for some /3, V-yJ ,3 for i =1, 2, then JIB, - B2111/2,..1/2 <C 3jj1h...case of anisotropic conductors we face a problem of nonuniqueness . One way to avoid the nonuniqueness issue is to convert the matrix conductivity to an

  7. Ferromagnetic resonance and ac conductivity of a polymer composite of Fe3O4 and Fe3C nanoparticles dispersed in a graphite matrix

    NASA Astrophysics Data System (ADS)

    Guskos, N.; Anagnostakis, E. A.; Likodimos, V.; Bodziony, T.; Typek, J.; Maryniak, M.; Narkiewicz, U.; Kucharewicz, I.; Waplak, S.

    2005-01-01

    Ferromagnetic resonance (FMR) and ac conductivity have been applied to study a polymer composite containing as filler a binary mixture of magnetite (Fe3O4) and cementite (Fe3C) nanoparticles (30-50nm) dispersed in a diamagnetic carbon matrix, which was synthesized by the carburization of nanocrystalline iron. Ac conductivity measurements showed thermally activated behavior involving a range of activation energies and power law frequency dependence at high frequencies similar to conducting polymer composites randomly filled with metal particles. Ferromagnetic resonance measurements revealed a relatively narrow FMR line at high temperatures indicating the presence of ferromagnetic nanoparticles, where thermal fluctuations and interparticle interactions determine the FMR temperature variation. An abrupt change of the FMR spectra was observed at T <81K (ΔT⩽1K) coinciding with a sharp anomaly resolved in the temperature derivative of the ac conductivity. This behavior is attributed to the Verwey transition of Fe3O4 nanoparticles, where the concurrent skin depth variation unveils the FMR of large magnetite conglomerates and thus allows discriminating their contribution from relatively isolated nanoparticles.

  8. Preliminary Results of Lightning Based Subsurface Conductivity Imaging

    NASA Astrophysics Data System (ADS)

    Strauss, D.; Linscott, I.; Inan, U. S.

    2009-12-01

    Manmade sources in the VLF frequency band have been successfully employed in controlled source electromagnetic methods since the 1970's. We demonstrate that natural sources primarily from lightning at these frequencies offer a comparable and promising source for subsurface geophysical imaging. Radio atmospherics, commonly known as 'sferics,' are an abundant source of broadband (1-30kHz), impulsive signals for probing the surface of the earth. We show that simultaneous measurement of three orthogonal components of the time-varying magnetic field using a network of Stanford-developed ELF/VLF receivers provides a promising dataset for specifying subsurface material properties. Conductive anomalies in the subsurface have been observed to produce anomalous magnetic field response that fits in a perturbation model of the Earth-Ionosphere waveguide model of propagation at VLF frequencies. We present here the initial findings of the simultaneous collection of thousands of sferics in three distinct geologic settings in Western Nevada, Kansas, and Idaho.

  9. Presentation, management, and outcomes of 25 748 acute coronary syndrome admissions in Kerala, India: results from the Kerala ACS Registry

    PubMed Central

    Mohanan, Padinhare Purayil; Mathew, Rony; Harikrishnan, Sadasivan; Krishnan, Mangalath Narayanan; Zachariah, Geevar; Joseph, Jhony; Eapen, Koshy; Abraham, Mathew; Menon, Jaideep; Thomas, Manoj; Jacob, Sonny; Huffman, Mark D.; Prabhakaran, Dorairaj

    2013-01-01

    Aims There are limited contemporary data on the presentation, management, and outcomes of acute coronary syndrome (ACS) admissions in India. We aimed to develop a prospective registry to address treatment and health systems gaps in the management of ACSs in Kerala, India. Methods and results We prospectively collected data on 25 748 consecutive ACS admissions from 2007 to 2009 in 125 hospitals in Kerala. We evaluated data on presentation, management, and in-hospital mortality and major adverse cardiovascular events (MACE). We created random-effects multivariate regression models to evaluate predictors of outcomes while accounting for confounders. Mean (SD) age at presentation was 60 (12) years and did not differ among ACS types [ST-segment myocardial infarction (STEMI) = 37%; non-STEMI = 31%; unstable angina = 32%]. In-hospital anti-platelet use was high (>90%). Thrombolytics were used in 41% of STEMI, 19% of non-STEMI, and 11% of unstable angina admissions. Percutaneous coronary intervention rates were marginally higher in STEMI admissions. Discharge medication rates were variable and generally suboptimal (<80%). In-hospital mortality and MACE rates were highest for STEMI (8.2 and 10.3%, respectively). After adjustment, STEMI diagnosis (vs. unstable angina) [odds ratio (OR) (95% confidence interval = 4.06 (2.36, 7.00)], symptom-to-door time >6 h [OR = 2.29 (1.73, 3.02)], and inappropriate use of thrombolysis [OR = 1.33 (0.92, 1.91)] were associated with higher risk of in-hospital mortality and door-to-needle time <30 min [OR = 0.44 (0.27, 0.72)] was associated with lower mortality. Similar trends were seen for risk of MACE. Conclusion These data represent the largest ACS registry in India and demonstrate opportunities for improving ACS care. PMID:22961945

  10. An Actual Design of AC Filter for Static Var Compensator and Verification Results from the Field Test

    NASA Astrophysics Data System (ADS)

    Tamura, Yuji; Takasaki, Shinji; Irokawa, Shoichi; Takeda, Hideo; Takagi, Kikuo; Noro, Yasuhiro; Ametani, Akihiro

    AC filter design method for SVC and HVDC is commonly known in the relevant CIGRE technical brochure and IEC technical report. However the conventional method requires many iterative calculations of the harmonic voltages and currents until the calculation results become within the regulation levels by changing filter parameters based on the experience. In this respect, a new improved design method is proposed, which enables efficient evaluation on the complex impedance plane to confirm as to whether the proposed filter impedance is in the permissible range. In an actual project of Okuura SVC of Kyusyu Electric Power Co., Inc., the new method was applied to the AC filter design. This paper describes on the actual procedure of the AC filter design with the new method, the actual references of the harmonic performance calculation, and the field test measurement results on Okuura SVC. The calculation results and the filed measurement results are consistent with each other, thus the validity of the new design method is verified on its accuracy and effectiveness.

  11. AC Electrical Conduction of Cr-Doped SrTiO3 Thin Films with an Oxygen-Deficient Interface Layer

    NASA Astrophysics Data System (ADS)

    Phan, Bach Thang; Eom, Ki Tae; Lee, Jaichan

    2017-01-01

    The ac electrical conduction of Cr-doped SrTiO3 thin films with an oxygen-deficient interface layer was investigated as a function of temperature and frequency. The Cr-doped SrTiO3 (Cr-STO) thin films with an ultra-thin (˜2 nm) oxygen-deficient layer inserted between the top electrode and the Cr-STO layer exhibited two ac conduction mechanisms, i.e., variable-range hopping and small-polaron hopping conduction, accompanied by a relaxation process. Since high oxygen deficiency induces large lattice distortion in the depletion layer, the first relaxation process occurs at low frequencies in the thin oxygen depletion layer Cr-SrTiO3-δ , and the corresponding conduction behavior follows the small-polaron tunneling model. In the high frequency range, an additional relaxation process is involved and is associated with the variable-range hopping between the localized states in the band gap of the thick Cr-SrTiO3 layer.

  12. Dielectric properties and study of AC electrical conduction mechanisms by non-overlapping small polaron tunneling model in Bis(4-acetylanilinium) tetrachlorocuprate(II) compound

    NASA Astrophysics Data System (ADS)

    Abkari, A.; Chaabane, I.; Guidara, K.

    2016-09-01

    In the present work, the synthesis and characterization of the Bis(4-acetylanilinium) tetrachlorocuprate(II) compound are presented. The structure of this compound is analyzed by X-ray diffraction which confirms the formation of single phase and is in good agreement the literature. Indeed, the Thermo gravimetric Analysis (TGA) shows that the decomposition of the compound is observed in the range of 420-520 K. However, the differential thermal analysis (DTA) indicates the presence of a phase transition at T=363 k. Furthermore, the dielectric properties and AC conductivity were studied over a temperature range (338-413 K) and frequency range (200 Hz-5 MHz) using complex impedance spectroscopy. Dielectric measurements confirmed such thermal analyses by exhibiting the presence of an anomaly in the temperature range of 358-373 K. The complex impedance plots are analyzed by an electrical equivalent circuit consisting of resistance, constant phase element (CPE) and capacitance. The activation energy values of two distinct regions are obtained from log σT vs 1000/T plot and are found to be E=1.27 eV (T<363 K) and E=1.09 eV (363 Kac conductivity, σac, has been analyzed by Jonscher's universal power law σ(ω)=σdc+Aωs. The value of s is to be temperature-dependent, which has a tendency to increase with temperature and the non-overlapping small polaron tunneling (NSPT) model is the most applicable conduction mechanism in the title compound. Complex impedance spectra of [C8H10NO]2CuCl4 at different temperatures.

  13. Synthesis and characterization of cancrinite-type zeolite, and its ionic conductivity study by AC impedance analysis

    NASA Astrophysics Data System (ADS)

    Kriaa, A.; Ben Saad, K.; Hamzaoui, A. H.

    2012-12-01

    The synthesis of cancrinite in the system NaOH-SiO2-Al2O3-NaHCO3-H2O was performed, according to methods described in the literature, in an autoclave under hydrothermal conditions at T = 473 K. The electrical properties of cancrinite-type zeolite pellets were investigated by complex impedance spectroscopy in the temperature range 465-800°C. The effect of temperature on impedance parameters was studied using an impedance analyzer in a wide frequency range (1 Hz to 13 MHz). The real and imaginary parts of complex impedance trace semicircles in the complex plane are plotted. The bulk resistance of the material decreases with rise in temperature. This exhibits a typical negative temperature coefficient of resistance (NTCR) behavior of the material. The results of bulk electrical conductivity and its activation energy are presented. The modulus analysis suggests that the electrical transport processes in the material are very likely to be of electronic nature. Relaxation frequencies follow an Arrhenius behavior with activation energy values not comparable to those found for the electrical conductivity.

  14. Frequency and voltage dependence dielectric properties, ac electrical conductivity and electric modulus profiles in Al/Co3O4-PVA/p-Si structures

    NASA Astrophysics Data System (ADS)

    Bilkan, Çiğdem; Azizian-Kalandaragh, Yashar; Altındal, Şemsettin; Shokrani-Havigh, Roya

    2016-11-01

    In this research a simple microwave-assisted method have been used for preparation of cobalt oxide nanostructures. The as-prepared sample has been investigated by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM). On the other hand, frequency and voltage dependence of both the real and imaginary parts of dielectric constants (ε‧, ε″) and electric modulus (M‧ and M″), loss tangent (tanδ), and ac electrical conductivityac) values of Al/Co3O4-PVA/p-Si structures were obtained in the wide range of frequency and voltage using capacitance (C) and conductance (G/ω) data at room temperature. The values of ε‧, ε″ and tanδ were found to decrease with increasing frequency almost for each applied bias voltage, but the changes in these parameters become more effective in the depletion region at low frequencies due to the charges at surface states and their relaxation time and polarization effect. While the value of σ is almost constant at low frequency, increases almost as exponentially at high frequency which are corresponding to σdc and σac, respectively. The M‧ and M″ have low values at low frequencies region and then an increase with frequency due to short-range mobility of charge carriers. While the value of M‧ increase with increasing frequency, the value of M″ shows two peak and the peaks positions shifts to higher frequency with increasing applied voltage due to the decrease of the polarization and Nss effects with increasing frequency.

  15. Experimental and theoretical study of AC electrical conduction mechanisms of Organic-inorganic hybrid compound Bis (4-acetylanilinium) tetrachlorocadmiate (II)

    NASA Astrophysics Data System (ADS)

    Jellibi, A.; Chaabane, I.; Guidara, K.

    2016-06-01

    A new organic-inorganic bis (4-acetylaniline) tetrachlorocadmate [C8H10NO]2[CdCl4] can be obtained by slow evaporation at room temperature and characterized by X-ray powder diffraction. It crystallized in an orthorhombic system (Cmca space group). The material electrical properties were characterized by impedance spectroscopy technique in the frequency range from 209 Hz-5 MHz and temperature 413 to 460 K. Besides, the impedance plots show semicircle arcs at different temperatures and an electrical equivalent circuit has been proposed to interpret the impedance results. The circuits consist of the parallel combination of a resistance (R), capacitance (C) and fractal capacitance (CPE). The variation of the exponent s as a function of temperature suggested that the conduction mechanism in Bis (4-acetylanilinium) tetrachlorocadmiate compound is governed by two processes which can be ascribed to a hopping transport mechanism: correlated barrier hopping (CBH) model below 443 K and the small polaron tunneling (SPT) model above 443 K.

  16. AC conductivity and dielectric properties of 2-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1 H-pyrazol-4-ylimino)-2-(4-nitrophenyl)acetonitrile thin films

    NASA Astrophysics Data System (ADS)

    El-Menyawy, E. M.; Zeyada, H. M.; El-Nahass, M. M.

    2010-12-01

    The dark AC conductivity and dielectric properties of thermally evaporated 2-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1 H-pyrazol-4-ylimino)-2-(4-nitrophenyl)acetonitrile (DOPNA) thin films in sandwich structure employing symmetrical gold ohmic contacts have been investigated as function of temperature (303-443 K) and frequency (100 Hz-5 MHz). The AC conductivity, σAC( ω), is found to obey Jonscher's universal power law, σAC( ω)= Aω s ( ω is the angular frequency). The AC conductivity of DOPNA thin films has been analyzed with reference to various theoretical models. The correlated barrier hopping is found to be the dominant conduction mechanism for charge carrier transport; the maximum barrier height, hopping length and the density of localized states are estimated. The temperature dependence of the AC conductivity shows Arrhenius type with two thermal activation energies. The activation energies are determined as a function of frequency. The behavior of the real and imaginary parts of the dielectric constant as a function of both temperature and frequency is discussed.

  17. Low-temperature AC conductivity of Bi 2Sr 2CaCu 2O 8+ δ

    NASA Astrophysics Data System (ADS)

    Corson, J.; Orenstein, J.; Eckstein, J. N.; Bozovic, I.

    2000-05-01

    We report measurements of anamolously large dissipative conductivities, σ1, in Bi 2Sr 2CaCu 2O 8+ δ at low temperatures. We have measured the complex conductivity of Bi 2Sr 2CaCu 2O 8+ δ thin films at 100-600 GHz as a function of doping from the underdoped to the overdoped state. At low temperatures there exists a residual σ1 which scales with the T=0 superfluid density as the doping is varied. This residual σ1 is larger than the possible contribution to σ1 from a thermal population of quasiparticles (QP) at the d-wave gap nodes.

  18. Effects of prosodic boundary on /aC/ sequences: articulatory results

    NASA Astrophysics Data System (ADS)

    Tabain, Marija

    2003-05-01

    This study presents EMA (electromagnetic articulography) data on articulation of the vowel /a/ at different prosodic boundaries in French. Three speakers of metropolitan French produced utterances containing the vowel /a/, preceded by /tee/ and followed by one of six consonants /bee dee gee eff ess sh/ (three stops and three fricatives), with different prosodic boundaries intervening between the /a/ and the six different consonants. The prosodic boundaries investigated are the Utterance, the Intonational phrase, the Accentual phrase, and the Word. Data for the Tongue Tip, Tongue Body, and Jaw are presented. The articulatory data presented here were recorded at the same time as the acoustic data presented in Tabain [J. Acoust. Soc. Am. 113, 516-531 (2003)]. Analyses show that there is a strong effect on peak displacement of the vowel according to the prosodic hierarchy, with the stronger prosodic boundaries inducing a much lower Tongue Body and Jaw position than the weaker prosodic boundaries. Durations of both the opening movement into and the closing movement out of the vowel are also affected. Peak velocity of the articulatory movements is also examined, and, contrary to results for phrase-final lengthening, it is found that peak velocity of the opening movement into the vowel tends to increase with the higher prosodic boundaries, together with the increased magnitude of the movement between the consonant and the vowel. Results for the closing movement out of the vowel and into the consonant are not so clear. Since one speaker shows evidence of utterance-level articulatory declension, it is suggested that the competing constraints of articulatory declension and prosodic effects might explain some previous results on phrase-final lengthening.

  19. Dielectric and AC-conductivity studies of Dy2O3 doped (K0.5Na0.5)NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Peddigari, Mahesh; Thota, Subhash; Pamu, Dobbidi

    2014-08-01

    (K0.5Na0.5)NbO3 + x wt.% Dy2O3 (x = 0-1.5) ferroelectric ceramics were prepared by conventional solid state reaction method. XRD patterns revealed that orthorhombic symmetry has transformed into psuedocubic symmetry with increasing the substitution of Dy3+ in the Na+ site. Temperature and frequency dependences of relative dielectric permittivity maximum conforms the transformation from normal ferroelectric to relaxor ferroelectric behaviour. Frequency dependence of the relative dielectric permittivity maximum temperature observed for the samples with x ≥ 1.0 and satisfied the Vogel-Fulcher law. The diffuseness exponent γ (1.27-1.95) estimated from the high temperature slopes of the diffused dielectric permittivity data reveals that the degree of relaxor behavior increases with increasing the amount of Dy2O3. The temperature dependence of AC-conductivity σAC (T) analysis in the range 310 K < T < 470 K reveals the existence of variable range hopping of charge carriers with average hopping length RH and hopping energy EH are in the range 8.5-27 Å and 48-153 meV, respectively. Voltage dependent dielectric constant measurements confirm the ferroelectric nature of KNN+ x wt% Dy2O3 ceramics.

  20. AC conductivity and relaxation mechanism in (Nd1/2Li1/2)(Fe1/2V1/2)O3 ceramics

    NASA Astrophysics Data System (ADS)

    Nath, Susmita; Barik, Subrat Kumar; Choudhary, R. N. P.

    2016-05-01

    In the present study we have synthesized polycrystalline sample of (Nd1/2Li1/2)(Fe1/2V1/2)O3 ceramic by a standard high-temperature solid-state reaction technique. Studies of dielectric and electrical properties of the compound have been carried out in a wide range of temperature (RT - 400 °C) and frequency (1kHz - 1MHz) using complex impedance spectroscopic technique. The imaginary vs. real component of the complex impedance plot (Nyquist plot) of the prepared sample exhibits the existence of grain, grain boundary contributions in the complex electrical parameters and negative temperature coefficient of resistance (NTCR) type behavior like semiconductor. Details study of ac conductivity plot reveals that the material obeys universal Jonscher's power law.

  1. AC conductivity and dielectric relaxation in Ba(Sm 1/2Nb 1/2)O 3 ceramic

    NASA Astrophysics Data System (ADS)

    Kumar, Pritam; Singh, B. P.; Sinha, T. P.; Singh, N. K.

    2011-01-01

    The complex perovskite oxide a barium samarium niobate (BSN) synthesized by solid-state reaction technique has single phase with cubic structure. The scanning electron micrograph of the sample shows the average grain size of BSN∼1.22 μm. The field dependence of dielectric response and loss tangent were measured in the temperature range from 323 to 463 K and in the frequency range from 50 Hz to 1 MHz. The complex plane impedance plots show the grain boundary contribution for higher value of dielectric constant in the low frequency region. An analysis of the dielectric constant ( ε‧) and loss tangent (tan δ) with frequency was performed assuming a distribution of relaxation times as confirmed by the scaling behaviour of electric modulus spectra. The low frequency dielectric dispersion corresponds to DC conductivity. The logarithmic angular frequency dependence of the loss peak is found to obey the Arrhenius law with an activation energy of 0.71 eV. The frequency dependence of electrical data is also analyzed in the framework of conductivity and electric modulus formalisms. Both these formalisms show qualitative similarities in relaxation times. The scaling behaviour of imaginary part of electric modulus M″ and dielectric loss spectra suggest that the relaxation describes the same mechanism at various temperatures in BSN. All the observations indicate the polydispersive relaxation in BSN.

  2. 10 CFR 110.46 - Conduct resulting in termination of nuclear exports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Conduct resulting in termination of nuclear exports. 110.46 Section 110.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXPORT AND IMPORT OF NUCLEAR EQUIPMENT AND MATERIAL Review of License Applications § 110.46 Conduct resulting in termination of...

  3. 10 CFR 110.46 - Conduct resulting in termination of nuclear exports.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false Conduct resulting in termination of nuclear exports. 110.46 Section 110.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXPORT AND IMPORT OF NUCLEAR EQUIPMENT AND MATERIAL Review of License Applications § 110.46 Conduct resulting in termination of...

  4. 10 CFR 110.46 - Conduct resulting in termination of nuclear exports.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false Conduct resulting in termination of nuclear exports. 110.46 Section 110.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXPORT AND IMPORT OF NUCLEAR EQUIPMENT AND MATERIAL Review of License Applications § 110.46 Conduct resulting in termination of...

  5. 10 CFR 110.46 - Conduct resulting in termination of nuclear exports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false Conduct resulting in termination of nuclear exports. 110.46 Section 110.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXPORT AND IMPORT OF NUCLEAR EQUIPMENT AND MATERIAL Review of License Applications § 110.46 Conduct resulting in termination of...

  6. 10 CFR 110.46 - Conduct resulting in termination of nuclear exports.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Conduct resulting in termination of nuclear exports. 110.46 Section 110.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXPORT AND IMPORT OF NUCLEAR EQUIPMENT AND MATERIAL Review of License Applications § 110.46 Conduct resulting in termination of...

  7. 45 CFR 2554.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 4 2013-10-01 2013-10-01 false What kind of conduct will result in program fraud...) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 2554.2 What kind of conduct will result in program fraud enforcement? (a) Any person who...

  8. 45 CFR 2554.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 4 2012-10-01 2012-10-01 false What kind of conduct will result in program fraud...) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 2554.2 What kind of conduct will result in program fraud enforcement? (a) Any person who...

  9. 45 CFR 2554.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 4 2014-10-01 2014-10-01 false What kind of conduct will result in program fraud...) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 2554.2 What kind of conduct will result in program fraud enforcement? (a) Any person who...

  10. 45 CFR 2554.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false What kind of conduct will result in program fraud...) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 2554.2 What kind of conduct will result in program fraud enforcement? (a) Any person who...

  11. 45 CFR 2554.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false What kind of conduct will result in program fraud...) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 2554.2 What kind of conduct will result in program fraud enforcement? (a) Any person who...

  12. Disruption of the baculovirus core gene ac78 results in decreased production of multiple nucleocapsid-enveloped occlusion-derived virions and the failure of primary infection in vivo.

    PubMed

    Li, Sai-Nan; Wang, Jin-Yu; Yuan, Mei-Jin; Yang, Kai

    2014-10-13

    The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac78 gene is one of the baculovirus core genes. Recent studies showed that ac78 is essential for budded virion (BV) production and the embedding of occlusion-derived virion (ODV) into occlusion body during the AcMNPV life cycle. Here, we report that an ac78-knockout AcMNPV (vAc78KO) constructed in this study had different phenotypes than those described in the previous studies. A few infectious BVs were detected using titer assays, immunoblot analyses and plaque assays, indicating that ac78 is not essential for BV formation. Electron microscopy confirmed that the ac78 deletion did not affect nucleocapsid assembly and ODV formation. However, the numbers of multiple nucleocapsid-enveloped ODVs and ODV-embedded occlusion bodies were significantly decreased. Subsequently, the highly conserved amino acid residues 2-25 and 64-88 of Ac78, which are homologous to an oxidoreductase and cytochrome c oxidase, respectively, were demonstrated to play a crucial role in the morphogenesis of multiple nucleocapsid-enveloped ODV. Immunoblot analysis found that Ac78 was an ODV envelope-associated protein. Consistently, amino acid residues 56-93 of Ac78 were identified as an inner nuclear membrane sorting motif, which may direct the localization of Ac78 to the ODV envelope. In vivo infectivity assays showed that the occlusion bodies of vAc78KO were unable to establish primary infection in the midgut of Trichoplusia ni larvae. Taken together, our results suggest that ac78 plays an important role in BV production and proper multiple nucleocapsid-enveloped ODV formation, as well as AcMNPV primary infection in vivo.

  13. Structural, magnetic, DC-AC electrical conductivities and thermo electric studies of MgCuZn Ferrites for microinductor applications.

    PubMed

    Varalaxmi, N; Sivakumar, K V

    2013-01-01

    Multilayer chip inductors (MLCIs) have been rapidly developed for electromagnetic applications. NiCuZn ferrites are the most preferred ferrite materials to produce MLCIs. MgCuZn ferrites have similar properties to those of NiCuZn ferrites. MgCuZn ferrites owing to their superior properties like low magnetostriction, environmental stability, low stress sensitivity, high resistivity and low cost can replace NiCuZn ferrites, which have a wide range of electronic applications. In view of this, a series of polycrystalline MgCuZn ferrites with generic formula MgxCu0.5Zn0.5-xFe2O4 (X=0.0 0.1, 0.2, 0.3, 0.4 and 0.5) are successfully synthesized by conventional double sintering technique. The samples were then characterized by the X-ray diffraction patterns (XRD) microstructural studies and the grain size was estimated using SEM micrographs. The sintered ferrites have been investigated in their magnetic, electrical and thermoelectric effect studies, which were carried out in the temperature range from 30 °C to 490 °C. The investigated ferrites are found to exhibit excellent properties that are suitable for the core materials in multilayer chip inductors, and the results are discussed.

  14. Reduction of Common-Mode Conducted Noise Emissions in PWM Inverter-fed AC Motor Drive Systems using Optimized Passive EMI Filter

    NASA Astrophysics Data System (ADS)

    Jettanasen, C.; Ngaopitakkul, A.

    2010-10-01

    Conducted electromagnetic interference (EMI) generated by PWM inverter-fed induction motor drive systems, which are currently widely used in many industrial and/or avionic applications, causes severe parasitic current problems, especially at high frequencies (HF). These restrict power electronic drive's evolution. In order to reduce or minimize these EMI problems, several techniques can be applied. In this paper, insertion of an optimized passive EMI filter is proposed. This filter is optimized by taking into account real impedances of each part of a considered AC motor drive system contrarily to commercial EMI filters designed by considering internal impedance of disturbance source and load, equal to 50Ω. Employing the latter EMI filter would make EMI minimization less effective. The proposed EMI filter optimization is mainly dedicated to minimize common mode (CM) currents due to its most dominant effects in this kind of system. The efficiency of the proposed optimization method using two-port network approach is deduced by comparing the minimized CM current spectra to an applied normative level (ex. DO-160D in aeronautics).

  15. Influence of temperature on the electric, dielectric and AC conductivity properties of nano-crystalline zinc substituted cobalt ferrite synthesized by solution combustion technique

    NASA Astrophysics Data System (ADS)

    Rani, Ritu; Kumar, Gagan; Batoo, Khalid M.; Singh, M.

    2014-06-01

    Cobalt-zinc nanoferrites with formulae Co ZnFeO, where x = 0.0, 0.1, 0.2 and 0.3, have been synthesized by solution combustion technique. The variation of DC resistivity with temperature shows the semiconducting behavior of all nanoferrites. The dielectric properties such as dielectric constant (') and dielectric loss tangent (tan are investigated as a function of temperature and frequency. Dielectric constant and loss tangent are found to be increasing with an increase in temperature while with an increase in frequency both, ' and tan , are found to be decreasing. The dielectric properties have been explained on the basis of space charge polarization according to Maxwell-Wagner's two-layer model and the hopping of charge between Fe and Fe. Further, a very high value of dielectric constant and a low value of tan are the prime achievements of the present work. The AC electrical conductivity ( is studied as a function of temperature as well as frequency and is observed to be increasing with the increase in temperature and frequency.

  16. Thermal conductivity of silicic tuffs: predictive formalism and comparison with preliminary experimental results

    SciTech Connect

    Lappin, A. R.

    1980-07-01

    Performance of both near- and far-field thermomechanical calculations to assess the feasibility of waste disposal in silicic tuffs requires a formalism for predicting thermal conductivity of a broad range of tuffs. This report summarizes the available thermal conductivity data for silicate phases that occur in tuffs and describes several grain-density and conductivity trends which may be expected to result from post-emplacement alteration. A bounding curve is drawn that predicts the minimum theoretical matrix (zero-porosity) conductivity for most tuffs as a function of grain density. Comparison of experimental results with this curve shows that experimental conductivities are consistently lower at any given grain density. Use of the lowered bounding curve and an effective gas conductivity of 0.12 W/m{sup 0}C allows conservative prediction of conductivity for a broad range of tuff types. For the samples measured here, use of the predictive curve allows estimation of conductivity to within 15% or better, with one exception. Application and possible improvement of the formalism are also discussed.

  17. Microtubule alignment and manipulation using AC electrokinetics.

    PubMed

    Uppalapati, Maruti; Huang, Ying-Ming; Jackson, Thomas N; Hancock, William O

    2008-09-01

    The kinesin-microtubule system plays an important role in intracellular transport and is a model system for integrating biomotor-driven transport into microengineered devices. AC electrokinetics provides a novel tool for manipulating and organizing microtubules in solution, enabling new experimental geometries for investigating and controlling the interactions of microtubules and microtubule motors in vitro. By fabricating microelectrodes on glass substrates and generating AC electric fields across solutions of microtubules in low-ionic-strength buffers, bundles of microtubules are collected and aligned and the electrical properties of microtubules in solution are measured. The AC electric fields result in electro-osmotic flow, electrothermal flow, and dielectrophoresis of microtubules, which can be controlled by varying the solution conductivity, AC frequency, and electrode geometry. By mapping the solution conductivity and AC frequency over which positive dielectrophoresis occurs, the apparent conductivity of taxol-stabilized bovine-brain microtubules in PIPES buffer is measured to be 250 mS m(-1). By maximizing dielectrophoretic forces and minimizing electro-osmotic and electrothermal flow, microtubules are assembled into opposed asters. These experiments demonstrate that AC electrokinetics provides a powerful new tool for kinesin-driven transport applications and for investigating the role of microtubule motors in development and maintenance of the mitotic spindle.

  18. Influence of probe geometry on measurement results of non-ideal thermal conductivity sensors

    NASA Astrophysics Data System (ADS)

    Tiefenbacher, Patrick; Kömle, Norbert I.; Macher, Wolfgang; Kargl, Günter

    2016-09-01

    The thermal properties of the surface and subsurface layers of planets and planetary objects yield important information that allows us to better understand the thermal evolution of the body itself and its interactions with the environment. Various planetary bodies of our Solar System are covered by so-called regolith, a granular and porous material. On such planetary bodies the dominant heat transfer mechanism is heat conduction via IR radiation and contact points between particles. In this case the energy balance is mainly controlled by the effective thermal conductivity of the top surface layers, which can be directly measured by thermal conductivity probes. A traditionally used method for measuring the thermal conductivity of solid materials is the needle-probe method. Such probes consist of thin steel needles with an embedded heating wire and temperature sensors. For the evaluation of the thermal conductivity of a specific material the temperature change with time is determined by heating a resistance wire with a well-defined electrical current flowing through it and simultaneously measuring the temperature increase inside the probe over a certain time. For thin needle probes with a large length-to-diameter ratio it is mathematically easy to derive the thermal conductivity, while this is not so straightforward for more rugged probes with a larger diameter and thus a smaller length-to-diameter ratio. Due to the geometry of the standard thin needle probes they are mechanically weak and subject to bending when driven into a soil. Therefore, using them for planetary missions can be problematic. In this paper the thermal conductivity values determined by measurements with two non-ideal, ruggedized thermal conductivity sensors, which only differ in length, are compared to each other. Since the theory describing the temperature response of non-ideal sensors is highly complicated, those sensors were calibrated with an ideal reference sensor in various solid and

  19. Authoritarian parenting attitudes as a risk for conduct problems Results from a British national cohort study.

    PubMed

    Thompson, Anne; Hollis, Chris; Dagger, David Richards

    2003-04-01

    This study examines the associations, and possible causal relationship, between mothers' authoritarian attitudes to discipline and child behaviour using cross-sectional and prospective data from a large population sample surveyed in the 1970 British Cohort Study. Results show a clear linear relationship between the degree of maternal approval of authoritarian child-rearing attitudes and the rates of conduct problems at age 5 and age 10. This association is independent of the confounding effects of socio-economic status and maternal psychological distress. Maternal authoritarian attitudes independently predicted the development of conduct problems 5 years later at age 10. The results of this longitudinal study suggest that authoritarian parenting attitudes expressed by mothers may be of significance in the development of conduct problems.

  20. 13 CFR 142.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... in program fraud enforcement? 142.2 Section 142.2 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 142.2 What kind of conduct will result in program fraud enforcement? (a) Any person who makes, or causes to be made, a...

  1. 13 CFR 142.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... in program fraud enforcement? 142.2 Section 142.2 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 142.2 What kind of conduct will result in program fraud enforcement? (a) Any person who makes, or causes to be made, a...

  2. 13 CFR 142.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... in program fraud enforcement? 142.2 Section 142.2 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 142.2 What kind of conduct will result in program fraud enforcement? (a) Any person who makes, or causes to be made, a...

  3. 13 CFR 142.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... in program fraud enforcement? 142.2 Section 142.2 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 142.2 What kind of conduct will result in program fraud enforcement? (a) Any person who makes, or causes to be made, a...

  4. 13 CFR 142.2 - What kind of conduct will result in program fraud enforcement?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... in program fraud enforcement? 142.2 Section 142.2 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION PROGRAM FRAUD CIVIL REMEDIES ACT REGULATIONS Overview and Definitions § 142.2 What kind of conduct will result in program fraud enforcement? (a) Any person who makes, or causes to be made, a...

  5. Analyses of temperature-dependent interface states, series resistances, and AC electrical conductivities of Al/p—Si and Al/Bi4Ti3O12/p—Si structures by using the admittance spectroscopy method

    NASA Astrophysics Data System (ADS)

    Mert, Yıldırım; Perihan, Durmuş; Şemsettin, Altındal

    2013-10-01

    In this study, Al/p—Si and Al/Bi4Ti3O12/p—Si structures are fabricated and their interface states (Nss), the values of series resistance (Rs), and AC electrical conductivityac) are obtained each as a function of temperature using admittance spectroscopy method which includes capacitance—voltage (C—V) and conductance—voltage (G—V) measurements. In addition, the effect of interfacial Bi4Ti3O12 (BTO) layer on the performance of the structure is investigated. The voltage-dependent profiles of Nss and Rs are obtained from the high-low frequency capacitance method and the Nicollian method, respectively. Experimental results show that Nss and Rs, as strong functions of temperature and applied bias voltage, each exhibit a peak, whose position shifts towards the reverse bias region, in the depletion region. Such a peak behavior is attributed to the particular distribution of Nss and the reordering and restructuring of Nss under the effect of temperature. The values of activation energy (Ea), obtained from the slope of the Arrhenius plot, of both structures are obtained to be bias voltage-independent, and the Ea of the metal-ferroelectric-semiconductor (MFS) structure is found to be half that of the metal—semiconductor (MS) structure. Furthermore, other main electrical parameters, such as carrier concentration of acceptor atoms (NA), built-in potential (Vbi), Fermi energy (EF), image force barrier lowering (Δ Φb), and barrier height (Φb), are extracted using reverse bias C-2—V characteristics as a function of temperature.

  6. Predicting saturated hydraulic conductivity from percolation test results in layered silt loam soils.

    PubMed

    Jabro, Jay D

    2009-12-01

    The objectives of the study discussed in this article were to develop an empirical relationship between the saturated hydraulic conductivity (Ks) of layered soils and their percolation times (PT) in order to understand the influence of individual layers and compare this with the equations developed by Winneberger (1974) and Fritton, Ratvasky, and Petersen (1986). Field research was conducted on three silt loam soils. Six holes were spaced evenly in two parallel rows of three holes. The Ks was measured at three different layers for each soil using a constant head well permeameter. After completion of the second Ks measurement, the percolation test was conducted. Three linear equations for the upper, middle, and lower layers were developed between the Ks values of each individual layer in all three sites and the corresponding PT. Significant differences were found between the author's results and those predicted by Winneberger (1974) and Fritton and co-authors (1986).

  7. The bone conduction implant: Clinical results of the first six patients

    PubMed Central

    Reinfeldt, Sabine; Håkansson, Bo; Taghavi, Hamidreza; Fredén Jansson, Karl-Johan; Eeg-Olofsson, Måns

    2015-01-01

    Abstract Objective: To investigate audiological and quality of life outcomes for a new active transcutaneous device, called the bone conduction implant (BCI), where the transducer is implanted under intact skin. Design: A clinical study with sound field audiometry and questionnaires at six-month follow-up was conducted with a bone-anchored hearing aid on a softband as reference device. Study sample: Six patients (age 18–67 years) with mild-to-moderate conductive or mixed hearing loss. Results: The surgical procedure was found uneventful with no adverse events. The first hypothesis that BCI had a statistically significant improvement over the unaided condition was proven by a pure-tone-average improvement of 31.0 dB, a speech recognition threshold improvement in quiet (27.0 dB), and a speech recognition score improvement in noise (51.2 %). At speech levels, the signal-to-noise ratio threshold for BCI was − 5.5 dB. All BCI results were better than, or similar to the reference device results, and the APHAB and GBI questionnaires scores showed statistically significant improvements versus the unaided situation, supporting the second and third hypotheses. Conclusions: The BCI provides significant hearing rehabilitation for patients with mild-to-moderate conductive or mixed hearing impairments, and can be easily and safely implanted under intact skin. PMID:25705995

  8. Discrete Element Modeling Results of Proppant Rearrangement in the Cooke Conductivity Cell

    SciTech Connect

    Earl Mattson; Hai Huang; Michael Conway; Lisa O'Connell

    2014-02-01

    The study of propped fracture conductivity began in earnest with the development of the Cooke cell which later became part of the initial API standard. Subsequent developments included a patented multicell design to conduct 4 tests in a press at the same time. Other modifications have been used by various investigators. Recent studies by the Stim-Lab proppant consortium have indicated that the flow field across a Cooke proppant conductivity testing cell may not be uniform as initially believed which resulted is significantly different conductivity results. Post test analysis of low temperature metal alloy injections at the termination of proppant testing prior to the release of the applied stress suggest that higher flow is to be expected along the sides and top of the proppant pack than compared to the middle of the pack. To evaluate these experimental findings, a physics-based two-dimensional (2-D) discrete element model (DEM) was developed and applied to simulate proppant rearrangement during stress loading in the Cooke conductivity cell and the resulting porosity field. Analysis of these simulations are critical to understanding the impact of modification to the testing cell as well as understanding key proppant conductivity issues such as how these effects are manifested in proppant concentration testing results. The 2-D DEM model was constructed to represent a realistic cross section of the Cooke cell with a distribution of four material properties, three that represented the Cooke cell (steel, sandstone,square rings), and one representing the proppant. In principle, Cooke cell materials can be approximated as assemblies of independent discrete elements (particles) of various sizes and material properties that interact via cohesive interactions, repulsive forces, and frictional forces. The macroscopic behavior can then be modeled as the collective behavior of many interacting discrete elements. This DEM model is particularly suitable for modeling proppant

  9. Electrical Conductivity and Anisotropy in Pacific Lithosphere: CSEM Results from APPLE

    NASA Astrophysics Data System (ADS)

    Behrens, J.; Constable, S.; MacGregor, L.; Everett, M.

    2002-12-01

    Emplacement of the sheeted dyke complex and strain associated with plate formation at mid-ocean ridge spreading centers may influence electrical conductivity at various depths in the lithosphere, and may leave an anisotropic fabric frozen in place. By measuring lithospheric electrical conductivity and anisotropy as a function of depth, insight may be gained regarding the formation and evolution of oceanic crust and mantle. Controlled-source electromagnetic (CSEM) sounding of 35 Ma Pacific lithosphere was undertaken as part of the Anisotropy and Physics of the Pacific Lithosphere Experiment (APPLE), carried out in February/March 2001 approximately 1000 km west of San Diego, California. Twenty seafloor electric field sensors were deployed (and recovered with data) during this experiment. The transmitter (DASI), a 100 m horizontal electric dipole, was deep-towed in a 30 km radius circle around a central core and perimeter array of receivers. An additional radial tow to 70 km total range and a 15 km radius semi-circular tow around a perimeter receiver supplemented the geometry of the main tow. DASI transmitted a 4 Hz square wave throughout the CSEM phase of the experiment. Smooth (and layered) inversion of short-offset (2-20 km) data, using 1-D isotropic modeling, generates models with upper-crustal resistivities ~10 Ω m, varying by about an order of magnitude across the survey area. Lower crustal resistivities are on the order of 103 Ω m. Smooth inversion of the long radial tow data indicates upper mantle resistivities of ~104 Ω m, with an increase in conductivity below 20 km depth. This may be due to thermally-activated olivine conduction, indicating that the base of the lithosphere has been detected. The integrated resistivity-thickness product for the top 100 km of our model is 1.1 x 109 Ω m2. A factor of two is observed in the electric fields measured during the circular tow, in a pattern that qualitatively resembles forward modeling results over an uniaxially

  10. Dielectric Relaxation Behavior and AC Electrical Conductivity Study of 2-(1,2-Dihydro-7-Methyl-2-Oxoquinoline-5-yl) Malononitrile (DMOQMN)

    NASA Astrophysics Data System (ADS)

    El-Nahass, M. M.; El-Zaidia, E. F. M.; Darwish, A. A. A.; Salem, G. F.

    2017-02-01

    Dielectric relaxation and alternative current conductivity of a new organic compound 2-(1,2-dihydro-7-methyl-2-oxoquinoline-5-yl) malononitrile (DMOQMN) have been investigated. X-ray diffraction (XRD) at room temperature reveals that DMOQMN samples have a polycrystalline structure of the triclinic system. The analysis of the dielectric constant and dielectric loss index suggested the dominant polarization is performed and the Maxwell-Wagner-Sillar type polarization is dominating at low frequency and high temperature. These results have been confirmed by the XRD and dielectric modulus. The estimated relaxation time and the activation energy are 9 × 10-13 s and 0.43 eV, respectively. Our results indicated that the conduction mechanism of DMOQMN is controlled by the correlation barrier hopping (CBH) model.

  11. Deuterium isotope effects on the ionization constant of acetic acid in H2O and D2O by AC conductance from 368 to 548 K at 20 MPa.

    PubMed

    Erickson, K M; Arcis, H; Raffa, D; Zimmerman, G H; Tremaine, P R

    2011-03-31

    Values of the ionization constant of acetic acid in H(2)O and D(2)O (K(HAc) and K(DAc)) and the deuterium isotope effect, ΔpK = pK(DAc) - pK(HAc), have been determined from T = 368 K to T = 548 K at p = 20 MPa, using a flow-through ac conductance cell built at the University of Delaware. Measurements were made on dilute (ionic strength ∼ 10(-4) mol·kg(-1)) solutions of acetic acid, sodium acetate, hydrochloric acid, and sodium chloride in H(2)O and D(2)O, injected in sequence at each temperature and pressure, so that systematic errors in the measured conductance of each solution would cancel. Experimental values for the molar conductivity, Λ, of the strong electrolytes were used to calculate the molar conductivity at infinite dilution, Λ°, using the Fuoss-Hsia-Fernández-Prini (FHFP) equation. These were used to calculate the molar conductivity at infinite dilution for acetic acid which was in turn used to calculate the degree of dissociation and finally the ionization constants of acetic acid. This same procedure was done for the pertinent deuterated solutes in D(2)O. Measured values of log K(HAc), log K(DAc), and ΔpK were obtained to a precision of ±0.008. The present results are in agreement with the only other accurate study at high temperatures and pressures (Mesmer, R. E.; Herting, D. L. J. Solution Chem.1978, 7, 901-913). The deuterium isotope effects, ΔpK, become independent of temperature above ∼420 K, at a value approximately 0.1 unit lower than that at 298 K. These values are ΔpK = 0.43 ± 0.01 and ΔpK = 0.51 ± 0.01, respectively. The temperature dependence of the Walden product ratio, (λ°η)(D(2)O)/(λ°η)(H(2)O), indicates a change in the relative hydration behavior of ions, whereby the effective Stokes radii of the sodium, chloride, and acetate ions in D(2)O relative to H(2)O reverse above ∼423 K. The results also suggest that the greater efficiency of the well-established proton-hopping transport mechanisms for OH(-) and H(3)O

  12. Variable conductance heat pipe technology. [research project resulting in heat pipe experiment on OAO-3 satellite

    NASA Technical Reports Server (NTRS)

    Anderson, W. T.; Edwards, D. K.; Eninger, J. E.; Marcus, B. D.

    1974-01-01

    A research and development program in variable conductance heat pipe technology is reported. The project involved: (1) theoretical and/or experimental studies in hydrostatics, (2) hydrodynamics, (3) heat transfer into and out of the pipe, (4) fluid selection, and (5) materials compatibility. The development, fabrication, and test of the space hardware resulted in a successful flight of the heat pipe experiment on the OAO-3 satellite. A summary of the program is provided and a guide to the location of publications on the project is included.

  13. Initial Results of Instrument-Flying Trials Conducted In A Single-Rotor Helicopter

    NASA Technical Reports Server (NTRS)

    Crim, Almer D; Reeder, John P; Whitten, James B

    1953-01-01

    Instrument-flying trials have been conducted in a single-rotor helicopter, the maneuver stability of which could be changed from satisfactory to unsatisfactory. The results indicated that existing longitudinal flying-qualities requirements based on contact flight were adequate for instrument flight at speeds above that for minimum power. However, lateral-directional problems were encountered at low speeds and during precision maneuvers. The adequacy, for helicopter use, of standard airplane instruments was also investigated, and the conclusion was reached that special instruments would be desirable under all conditions, and necessary for sustained low-speed instrument flight.

  14. The investigation of dielectric properties and ac conductivity of new ceramic diphosphate Ag0.6Na0.4FeP2O7 using impedance spectroscopy method

    NASA Astrophysics Data System (ADS)

    Nasri, S.; Megdiche, M.; Gargouri, M.

    2016-10-01

    In this paper, Ag0.6Na0.4FeP2O7 has been synthesized by solid state reaction method. The ceramic compound was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrational spectroscopy and impedance measurements. In fact, the investigated sample has shown single phase type monoclinic structure with P21/C space group. The frequency-dependent electrical data are analyzed in the frame-work of conductivity and electric modulus formalisms. The real and imaginary parts of complex impedance are well fitted to equivalent circuit model based on the Z-View-software. Besides, the observed frequency dependence of conductivity is found to obey Jonscher's universal law. The temperature dependence of both ac conductivity and the parameter s is reasonably well interpreted by the correlated barrier hopping (CBH). The theoretical fitting between the proposed model and the experimental data showed good agreement. The contribution of single polaron and bipolaron hopping to a.c. conductivity in present compound is also studied. The ionic conductivity is discussed on the basis of the structural characteristics of the sample.

  15. Suboccipital craniotomy for Chiari I results in evoked potential conduction changes

    PubMed Central

    Chen, Jason A.; Coutin-Churchman, Pedro E.; Nuwer, Marc R.; Lazareff, Jorge A.

    2012-01-01

    Background: Management of Chiari I is controversial, in part because there is no widely used quantitative measurement of decompression. It has been demonstrated that brainstem auditory evoked responses (BAER) and somatosensory evoked potentials (SSEP) have decreased conduction latencies after wide craniectomy. We analyzed these parameters in a suboccipital craniectomy/craniotomy procedure. Methods: Thirteen consecutive patients underwent suboccipital decompression for treatment of symptomatic Chiari I. Craniectomy was restricted to the inferior aspect of the nuchal line, and in most cases the bone flap was replaced. Neuronal conduction was monitored continuously with median nerve somatosensory evoked potentials (M-SEP), posterior tibial nerve somatosensory evoked potentials (T-SEP), BAER, or a combination. The M-SEP N20, T-SEP P37, and BAER V latencies were recorded at four milestones – preoperatively, following craniotomy, following durotomy, and following closure. Results: Five males and eight females, with average age of 9 years, were studied. Clinical improvement was noted in all 13 patients. M-SEP N20 latency decreased from a mean of 18.55 at baseline to 17.75 ms after craniotomy (P = 0.01); to 17.06 ms after durotomy (P = 0.01); and to 16.68 ms after closing (P = 0.02). T-SEP P37 latency did not change significantly. BAER V latency decreased from a mean of 6.25 ms at baseline to 6.14 ms after craniotomy (P = 0.04); to 5.98 ms after durotomy (P = 0.01); and to 5.95 ms after closing (P = 0.45). Conclusion: Significant improvements in conduction followed both craniectomy and durotomy. Bone replacement did not affect these results. PMID:23372981

  16. Results of the life sciences DSOs conducted aboard the space shuttle 1981-1986

    NASA Technical Reports Server (NTRS)

    Bungo, Michael W.; Bagian, Tandi M.; Bowman, Mark A.; Levitan, Barry M.

    1987-01-01

    Results are presented for a number of life sciences investigations sponsored by the Space Biomedical Research Institute at the NASA Lyndon B. Johnson Space Center and conducted as Detailed Supplementary Objectives (DSOs) on Space Shuttle flights between 1981 and 1986. An introduction and a description of the DSO program are followed by summary reports on the investigations. Reports are grouped into the following disciplines: Biochemistry and Pharmacology, Cardiovascular Effects and Fluid Shifts, Equipment Testing and Experiment Verification, Microbiology, Space Motion Sickness, and Vision. In the appendix, the status of every medical/life science DSO is presented in graphical form, which enables the flight history, the number of subjects tested, and the experiment results to be reviewed at a glance.

  17. Studies on structural, thermal and AC conductivity scaling of PEO-LiPF6 polymer electrolyte with added ionic liquid [BMIMPF6

    NASA Astrophysics Data System (ADS)

    Chaurasia, S. K.; Saroj, A. L.; Shalu, Singh, V. K.; Tripathi, A. K.; Gupta, A. K.; Verma, Y. L.; Singh, R. K.

    2015-07-01

    Preparation and characterization of polymer electrolyte films of PEO+10wt.% LiPF6 + xwt.% BMIMPF6 (1-butyl-3-methylimidazolium hexafluorophosphate) containing dopant salt lithium hexafluorophosphate (LiPF6) and ionic liquid (BMIMPF6) having common anion PF6 - are reported. The ionic conductivity of the polymer electrolyte films has been found to increase with increasing concentration of BMIMPF6 in PEO+10 wt.% LiPF6 due to the plasticization effect of ionic liquid. DSC and XRD results show that the crystallinity of polymer electrolyte decreases with BMIMPF6 concentration which, in turn, is responsible for the increase in ionic conductivity. FTIR spectroscopic study shows the complexation of salt and/or ionic liquid cations with the polymer backbone. Ion dynamics behavior of PEO+LiPF6 as well as PEO+LiPF6 + BMIMPF6 polymer electrolytes was studied by frequency dependent conductivity, σ(f) measurements. The values σ(f) at various temperatures have been analyzed in terms of Jonscher power law (JPL) and scaled with respect to frequency which shows universal power law characteristics at all temperatures.

  18. The results and analysis of irradiation experiments conducted on reactor vessel plate and weld materials

    SciTech Connect

    Biemiller, E.C.; Carter, R.G.; Rosinski, S.T.

    1996-09-01

    This paper documents the extensive amount of experimental work on radiation damage to reactor vessel materials carried out by Yankee Atomic Electric Company (YAEC) and others in support of a licensing effort to restart the Yankee Rowe nuclear power plant. The effect of plate nickel content and microstructure on irradiation damage sensitivity was assessed. Typical reactor pressure vessel plate materials each containing 0.24% (by weight) copper, but different nickel contents at 0.19% and 0.63% were heat treated to produce different microstructures. A Linde 80 weld containing 0.30% copper and 1.00% nickel was produced and heat treated to test microstructure effects on the irradiation response of weld metal. Materials taken from plate surface locations (vs 1/4%) were included to test whether or not the improved toughness properties of the plate surface layer, resulting from a rapid quench, is maintained after irradiation. Irradiations were conducted at two irradiation temperatures, 500 F (260 C) and 550 F (288 C), to determine the effect of irradiation temperature on embrittlement. The results of this irradiation testing and additional data from a DOE/Sandia National Laboratories irradiation study show an irradiation temperature effect that is not consistent, but varies with the materials tested. The test results demonstrate that for nickel bearing steels, the superior toughness of plate surface material is maintained even after irradiation to high fluences, and for the copper content tested, nickel has little effect on irradiation response. A mixed effect of microstructure/heat treatment on the materials` irradiation response was noted. Phosphorus potentially played a role in the irradiation response of the low nickel material irradiated at 500 F (288 C) but did not show prominence in the irradiations for the same material conducted at 500 F (260 C).

  19. Functional results after Bonebridge implantation in adults and children with conductive and mixed hearing loss.

    PubMed

    Rahne, Torsten; Seiwerth, Ingmar; Götze, Gerrit; Heider, Cornelia; Radetzki, Florian; Herzog, Michael; Plontke, Stefan K

    2015-11-01

    In patients with conductive hearing loss caused by middle ear disorders or atresia of the ear canal, a Bonebridge implantation can improve hearing by providing vibratory input to the temporal bone. The expected results are improved puretone thresholds and speech recognition. In the European Union, approval of the Bonebridge implantation was recently extended to children. We evaluated the functional outcome of a Bonebridge implantation for eight adults and three children. We found significant improvement in the puretone thresholds, with improvement in the air-bone gap. Speech recognition after surgery was significantly higher than in the best-aided situation before surgery. The Bonebridge significantly improved speech recognition in noisy environments and sound localization. In situations relevant to daily life, hearing deficits were nearly completely restored with the Bonebridge implantation in both adults and children.

  20. Enhancements in Glovebox Design Resulting from Laboratory-Conducted FIre Tests

    SciTech Connect

    Brooks, Kriston P.; Wunderlich, Gregory M.; Mcentire, James R.; Richmond, William G.

    2013-06-14

    The primary mission of the Pit Disassembly and Conversion Facility (PDCF) Project was to disassemble nuclear weapons pits and convert the resulting special nuclear materials to a form suitable for further disposition. Because of the nature of materials involved, the fundamental system which allowed PDCF to perform its mission was a series of integrated and interconnected gloveboxes which provided confinement and containment of the radioactive materials being processed. The high throughput planned for PDCF and the relatively high neutron and gamma radiation levels of the pits required that gloveboxes be shielded to meet worker dose limits. The glovebox shielding material was required to contain high hydrogen concentrations which typically result in these materials being combustible. High combustible loadings created design challenges for the facility fire suppression and ventilation system design. Combustible loading estimates for the PDCF Plutonium (Pu) Processing Building increased significantly due to these shielding requirements. As a result, the estimates of combustible loading substantially exceeded values used to support fire and facility safety analyses. To ensure a valid basis for combustible loading contributed by the glovebox system, the PDCF Project funded a series of fire tests conducted by the Southwest Research Institute on door panels and a representative glovebox containing Water Extended Polyester (WEP) radiological shielding to observe their behavior during a fire event. Improvements to PDCF glovebox designs were implemented based on lessons learned during the fire test. In particular, methods were developed to provide high levels of neutron shielding while maintaining combustible loading in the glovebox shells at low levels. Additionally, the fire test results led to design modifications to mitigate pressure increases observed during the fire test in order to maintain the integrity of the WEP cladding. These changes resulted in significantly

  1. Theory of hopping conductivity in pig insulin

    NASA Astrophysics Data System (ADS)

    Ye, Yuan-Jie; Ladik, János

    1993-08-01

    The ac conductivity for a native protein, pig insulin, was calculated in the ab initio scheme using Clementi's minimal basis set. The hopping centers and ``main residue'' of an orbital are defined. It is assumed that the hopping events of charge carriers happen among these centers of main residues. The analysis of primary hopping events shows that there might be a relationship between the distribution of the hopping centers and the biochemical activity of insulin, and that the disulfur bridges of insulin have particular relevance for the ac conduction. The formulas for calculation of the ac conductivity of proteins are given. The results show that the curve of the frequency versus ac conductivity of pig insulin lies in the range of some typical inorganic amorphous conductors and confirm that proteins if doped are amorphous conductors. Finally, the possibility of direct comparison of the theoretical results with experiments is discussed.

  2. Coffee ring effect resulted conductive nanowire patterns by evaporating colloidal suspension droplets without sintering process

    NASA Astrophysics Data System (ADS)

    Wang, Xiaofeng; Seong, Baekhoon; Yudistira, Hadi Teguh; Byun, Doyoung

    2015-11-01

    Drying colloidal suspensions containing non-volatile solute will form a ring like pattern, which is called ``coffee ring effect.'' Here, we present the coffee ring effect with silver nanowires dispersing into DI water, resulting in a highly dense-packed nanowire ring patterns. The effect of nanowire length, concentration, droplet size, and substrate temperature were investigated. With shorter nanowires, a distinct ring could be obtained. Meanwhile, the concentration of the colloidal suspension was found to affect the ring width. The droplet size and nanowire length played a significant role in affecting the occurrence of the coffee ring effect. When smaller droplets (i.e., less than 150 μm) containing long nanowires (~ 20 μm), the coffee ring effect was suppressed. While smaller droplets containing short nanowires (~ 1 μm), the coffee ring effect was not affected. By increasing the temperature of the substrate, multi-ring pattern was formed inside the original ring. The resistivity of the semi-circle of the nanowire ring was measured, and had a minimum value of 1.32 × 10-6 Ωm without any sintering process. These findings could be exploited to basic study of ring stain effect as well as the practical use, such as evaporative lithography and ink-jet printing for conductive film and display. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (Grant number: 2014-023284).

  3. Numerical simulation of ac plasma arc thermodynamics

    NASA Astrophysics Data System (ADS)

    Wu, Han-Ming; Carey, G. F.; Oakes, M. E.

    1994-05-01

    A mathematical model and approximate analysis for the energy distribution of an ac plasma arc with a moving boundary is developed. A simplified electrical conductivity function is assumed so that the dynamic behavior of the arc may be determined, independent of the gas type. The model leads to a reduced set of non-linear partial differential equations which governs the quasi-steady ac arc. This system is solved numerically and it is found that convection plays an important role, not only in the temperature distribution, but also in arc disruptions. Moreover, disruptions are found to be influenced by convection only for a limited frequency range. The results of the present studies are applicable to the frequnecy range of 10-10(exp 2) Hz which includes most industry ac arc frequencies.

  4. Numerical Simulation of AC Plasma Arc Thermodynamics

    NASA Astrophysics Data System (ADS)

    Wu, Han-Ming; Carey, G. F.; Oakes, M. E.

    1994-05-01

    A mathematical model and approximate analysis for the energy distribution of an ac plasma arc with a moving boundary is developed. A simplified electrical conductivity function is assumed so that the dynamic behavior of the arc may be determined, independent of the gas type. The model leads to a reduced set of non-linear partial differential equations which governs the quasi-steady ac arc. This system is solved numerically and it is found that convection plays an important role, not only in the temperature distribution, but also in arc disruptions. Moreover, disruptions are found to be influenced by convection only for a limited frequency range. The results of the present studies are applicable to the frequency range of 10-102 Hz which includes most industry ac arc frequencies.

  5. Structural characterization, thermal, ac conductivity and dielectric properties of (C7H12N2)2[SnCl6]Cl2.1.5H2O

    NASA Astrophysics Data System (ADS)

    Hajji, Rachid; Oueslati, Abderrazek; Hajlaoui, Fadhel; Bulou, Alain; Hlel, Faouzi

    2016-05-01

    (C7H12N2)2[SnCl6]Cl2.1.5H2O is crystallized at room temperature in the monoclinic system (space group P21/n). The isolated molecules form organic and inorganic layers parallel to the (a, b) plane and alternate along the c-axis. The inorganic layer is built up by isolated SnCl6 octahedrons. Besides, the organic layer is formed by 2,4-diammonium toluene cations, between which the spaces are filled with free Cl- ions and water molecules. The crystal packing is governed by means of the ionic N-H...Cl and Ow-H...Cl hydrogen bonds, forming a three-dimensional network. The thermal study of this compound is reported, revealing two phase transitions around 360(±3) and 412(±3) K. The electrical and dielectric measurements were reported, confirming the transition temperatures detected in the differential scanning calorimetry (DSC). The frequency dependence of ac conductivity at different temperatures indicates that the correlated barrier hopping (CBH) model is the probable mechanism for the ac conduction behavior.

  6. Oceanography at coastal scales: Introduction to the special issue on results from the EU FP7 FIELD_AC project

    NASA Astrophysics Data System (ADS)

    Sánchez-Arcilla, Agustín; Wolf, Judith; Monbaliu, Jaak

    2014-09-01

    The high-resolution and coupled forecasting of wind, waves and currents, in restricted coastal domains, offer a number of important challenges; these limit the quality of predictions, in the present state-of-the-art. This paper presents the main results obtained for such coastal domains, with reference to a variety of modelling suites and observing networks for: a) Liverpool Bay; b) German Bight; c) Gulf of Venice; and d) the Catalan coast. All of these areas are restricted domains, where boundary effects play a significant role in the resulting inner dynamics. This contribution addresses also the themes of the other papers in this Special Issue, ranging from observations to simulations. Emphasis is placed upon the physics controlling such restricted areas. The text deals also with the transfer to end-users and other interested parties, since the requirements on resolution, accuracy and robustness must be linked to their applications. Finally, some remarks are included on the way forward for coastal oceanography and the synergetic combination of in-situ and remote measurements, with high-resolution 3D simulations.

  7. Perceptions of breath alcohol concentration (BrAC) levels among a sample of bar patrons with BrAC values of 0.08% or higher.

    PubMed

    Martin, Ryan J; Chaney, Beth H; Cremeens-Matthews, Jennifer; Vail-Smith, Karen

    2016-09-01

    Breath alcohol concentration (BrAC) is a commonly used measure of alcohol intoxication. Because of the potential negative consequences of excessive alcohol consumption, it is important to examine how accurately intoxicated individuals can estimate their BrAC values, especially individuals over the legal BrAC driving threshold (i.e., 0.08%). To better understand perceptions of BrAC values among intoxicated individuals, this field study examined actual BrAC values and BrAC range estimates (0.08% and above, 0.02-0.07%, less than 0.02%) among a sample of bar patrons (N = 454) with BrAC levels at 0.08% or higher. Bivariate and multivariate analyses were conducted to examine the relationship between actual BrAC values and perceived BrAC levels. We also examined whether the following demographic and drinking variables were associated with underestimating BrAC in this sample: gender, age, race, college student status, plans to get home, and hazardous drinking. Results indicated that the majority (60.4%) of participants underestimated their BrAC (i.e., less than 0.08%) and lower BrAC values correlated with underestimating BrAC ranges (p < .001, 95% CI[0.2, 0.6]). Further, females (p = .001, 95% CI[1.3, 3.3]) and participants under 21 (p = .039, 95% CI = 1.0, 2.6) were significantly more likely to estimate their BrAC to be less than 0.08%, which is concerning given that young (less than 21) intoxicated females are a group at high risk for sexual assault on college campuses. (PsycINFO Database Record

  8. LABORATORY AND FIELD RESULTS LINKING HIGH BULK CONDUCTIVITIES TO THE MICROBIAL DEGRADATION OF PETROLEUM HYDROCARBONS

    EPA Science Inventory

    Diesel contaminated layer (i.e. 32-45 cm) was the most geoelectrically conductive and showed the peak microbial activity. Below the saturated zone microbial enhanced mineral weathering increases the ionic concentration of pore fluids, leading to increased bulk electrical conducit...

  9. Results of chronic toxicity tests conducted on selected A-area outfalls, June-August 1996

    SciTech Connect

    Specht, W.L.

    1997-07-01

    In anticipation of possible toxicity testing requirements in the SRS`s new (1996) NPDES permit, toxicity tests were performed at selected A-Area NPDES outfalls in order to determine if the outfalls were toxic. Chronic definitive toxicity tests were conducted on Ceriodaphnia dubia using water collected from nine locations during the summer of 1996. Six of the nine locations were toxic.

  10. A Preliminary Comparison of Functional Analysis Results when Conducted in Contrived versus Natural Settings

    ERIC Educational Resources Information Center

    Lang, Russell; O'Reilly, Mark; Machalicek, Wendy; Lancioni, Giulio; Rispoli, Mandy; Chan, Jeffrey M.

    2008-01-01

    A preliminary evaluation of the correspondence between functional analysis outcomes across settings was conducted with 2 children who had been diagnosed with autism and who engaged in challenging behavior. Differences across settings (a therapy room and a classroom) were demonstrated in ABAB reversal designs. Three potential patterns of results…

  11. Results of acute and chronic toxicity tests conducted at SRS NPDES outfalls, July--October 1991

    SciTech Connect

    Specht, W.L.

    1992-01-01

    Acute (48 hour LC50) and chronic (7-day reproductive impairment) toxicity tests were conducted on Ceriodaphnia dubia in water collected from 53 NPDES outfalls. All tests were conducted at the in-stream waste concentration. only 12 of the 53 outfalls showed no evidence of toxicity. Twenty-eight of the outfalls were acutely toxic, often producing 100% mortality during the first day of exposure. Fourteen outfalls had no discharge at the time of sampling and could not be tested. Three outfalls were not tested because their toxicity has been adequately characterized in other investigations. Elevated concentrations of total residual chlorine are suspected to be responsible for the observed toxicity of many NPDES outfalls, particularly the sanitary wastewater treatment plants. Chemical data from previous studies indicate that metals may also be present in toxic concentrations at many outfalls. Toxicity identification and reduction options are discussed.

  12. Imbalance in Multiple Sclerosis: A Result of Slowed Spinal Somatosensory Conduction

    PubMed Central

    Cameron, Michelle H.; Horak, Fay B.; Herndon, Robert R.; Bourdette, Dennis

    2009-01-01

    Balance problems and falls are common in people with multiple sclerosis (MS) but their cause and nature are not well understood. It is known that MS affects many areas of the central nervous system that can impact postural responses to maintain balance, including the cerebellum and the spinal cord. Cerebellar balance disorders are associated with normal latencies but reduced scaling of postural responses. We therefore examined the latency and scaling of automatic postural responses, and their relationship to somatosensory evoked potentials (SSEPs), in 10 people with MS and imbalance and 10 age-, sex-matched, healthy controls. The latency and scaling of postural responses to backward surface translations of 5 different velocities and amplitudes, and the latency of spinal and supraspinal somatosensory conduction, were examined. Subjects with MS had large, but very delayed automatic postural response latencies compared to controls (161ms ± 31 vs 102 ± 21, p < 0.01) and these postural response latencies correlated with the latencies of their spinal SSEPs (r=0.73, p< 0.01). Subjects with MS also had normal or excessive scaling of postural response amplitude to perturbation velocity and amplitude. Longer latency postural responses were associated with less velocity scaling and more amplitude scaling. Balance deficits in people with MS appear to be caused by slowed spinal somatosensory conduction and not by cerebellar involvement. People with MS appear to compensate for their slowed spinal somatosensory conduction by increasing the amplitude scaling and the magnitude of their postural responses. PMID:18570015

  13. Electrical Conductivity and Anisotropy in Pacific Lithosphere: CSEM Results from APPLE

    NASA Astrophysics Data System (ADS)

    Behrens, J.; Constable, S.; Everett, M.; MacGregor, L.

    2003-12-01

    Strain associated with plate formation at mid-ocean ridge spreading centers may influence electrical conductivity at various depths in the lithosphere, and may leave an anisotropic fabric frozen in place. By measuring lithospheric electrical conductivity and anisotropy, insight may be gained regarding the formation and evolution of oceanic crust and mantle. Controlled-source electromagnetic (CSEM) sounding of 35 Ma Pacific lithosphere was undertaken as part of the Anisotropy and Physics of the Pacific Lithosphere Experiment (APPLE), carried out approximately 1000 km west of San Diego. The transmitter (DASI), with a 100 m horizontal electric dipole antenna, was deep-towed in a 30 km radius circle around an array of receivers. A radial tow to 70 km total range and a 15 km radius semi-circular tow supplemented the geometry of the main tow. DASI transmitted a 4 Hz square wave throughout the CSEM phase of the experiment. Smooth (and layered) inversions of short-offset (2-20 km) data, using 1-D isotropic modeling, generate models with upper-crustal resistivities ˜1 Ω m, varying by about an order of magnitude across the survey area. Lower crustal resistivities are on the order of 103 Ω m. Smooth inversion of the long radial tow data indicates upper mantle resistivities of ˜104 Ω m, with an increase in conductivity below 20 km depth. This may be due to thermally-activated olivine conduction, indicating that the base of the lithosphere has been detected. The integrated resistivity-thickness product for the top 100 km of our model is 1.1 x 109 Ω m2. The electric field is characterized in terms of the polarization ellipse parameters. During the circular tow, the maximum axis varies by a factor of two, while the minimum axis varies by a factor of 5. Forward calculations were run on models with a uniaxially anisotropic layer sandwiched between two isotropic layers. Simulated data from models with increased conductivity perpendicular to the paleo-spreading direction in the

  14. Results of Scoping Tests Examining the Effects of Gilsulate, Aluminum Silicate and Defoamers on the Operation of Conductivity Level Probes

    SciTech Connect

    Swingle, R.F.

    1999-02-17

    Scoping tests have been completed examining the effects of Gilsulate, sodium aluminum silicate, and some organic materials on the operation of tank level conductivity probes. This report documents the results of scoping studies completed to examine the effect of those materials on conductivity probes.

  15. 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.

  16. A type III ACC synthase, ACS7, is involved in root gravitropism in Arabidopsis thaliana.

    PubMed

    Huang, Shih-Jhe; Chang, Chia-Lun; Wang, Po-Hsun; Tsai, Min-Chieh; Hsu, Pang-Hung; Chang, Ing-Feng

    2013-11-01

    Ethylene is an important plant hormone that regulates developmental processes in plants. The ethylene biosynthesis pathway is a highly regulated process at both the transcriptional and post-translational level. The transcriptional regulation of these ethylene biosynthesis genes is well known. However, post-translational modifications of the key ethylene biosynthesis enzyme 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) are little understood. In vitro kinase assays were conducted on the type III ACS, AtACS7, fusion protein and peptides to determine whether the AtACS7 protein can be phosphorylated by calcium-dependent protein kinase (CDPK). AtACS7 was phosphorylated at Ser216, Thr296, and Ser299 by AtCDPK16 in vitro. To investigate further the function of the ACS7 gene in Arabidopsis, an acs7-1 loss-of-function mutant was isolated. The acs7-1 mutant exhibited less sensitivity to the inhibition of root gravitropism by treatment with the calcium chelator ethylene glycol tetraacetic acid (EGTA). Seedlings were treated with gradient concentrations of ACC. The results showed that a certain concentration of ethylene enhanced the gravity response. Moreover, the acs7-1 mutant was less sensitive to inhibition of the gravity response by treatment with the auxin polar transport inhibitor 1-naphthylphthalamic acid, but exogenous ACC application recovered root gravitropism. Altogether, the results indicate that AtACS7 is involved in root gravitropism in a calcium-dependent manner in Arabidopsis.

  17. AC Electrokinetics of Physiological Fluids for Biomedical Applications.

    PubMed

    Lu, Yi; Liu, Tingting; Lamanda, Ariana C; Sin, Mandy L Y; Gau, Vincent; Liao, Joseph C; Wong, Pak Kin

    2015-12-01

    Alternating current (AC) electrokinetics is a collection of processes for manipulating bulk fluid mass and embedded objects with AC electric fields. The ability of AC electrokinetics to implement the major microfluidic operations, such as pumping, mixing, concentration, and separation, makes it possible to develop integrated systems for clinical diagnostics in nontraditional health care settings. The high conductivity of physiological fluids presents new challenges and opportunities for AC electrokinetics-based diagnostic systems. In this review, AC electrokinetic phenomena in conductive physiological fluids are described followed by a review of the basic microfluidic operations and the recent biomedical applications of AC electrokinetics. The future prospects of AC electrokinetics for clinical diagnostics are presented.

  18. AC Electrokinetics of Physiological Fluids for Biomedical Applications

    PubMed Central

    Lu, Yi; Liu, Tingting; Lamanda, Ariana C.; Sin, Mandy L Y; Gau, Vincent; Liao, Joseph C.; Wong, Pak Kin

    2016-01-01

    AC electrokinetics is a collection of processes for manipulating bulk fluid mass and embedded objects with AC electric fields. The ability of AC electrokinetics to implement the major microfluidic operations, such as pumping, mixing, concentration and separation, makes it possible to develop integrated systems for clinical diagnostics in non-traditional healthcare settings. The high conductivity of physiological fluids presents new challenges and opportunities for AC electrokinetics based diagnostic systems. In this review, AC electrokinetic phenomena in conductive physiological fluids are described followed by a review of the basic microfluidic operations and the recent biomedical applications of AC electrokinetics. The future prospects of AC electrokinetics for clinical diagnostics are presented. PMID:25487557

  19. Results of Toxicity Studies Conducted on Outfall X-08 and Its Contributing Waste Streams, November 1999 - June 2000

    SciTech Connect

    Specht, W.L.

    2000-06-28

    This interim report summarizes the results of toxicity tests, Toxicity Identification Evaluations, and chemical analyses that have been conducted on SRS's NPDES Outfall X-08 and its contributing waste streams between November 1999 and June 2000.

  20. ISEC-3: Results from the third in-situ electrical conductivity test on polycrystaline alumina

    SciTech Connect

    Snead, L.L.; White, D.P.; Eatherly, W.S.; Zinkle, S.J.

    1996-04-01

    An experimental investigation of radiation induced electrical degradation (RIED) has been performed at the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory. In this study (the third in a series of experiments at the HFBR) the effects of neutron irradiation on the electrical conductivity of Wesgo AL995 polycrystalline alumina has been investigated at approximately 450{degrees}C. The capsule design used in this study is very similiar to a design used in the first two experiments in this series with some improvements made to a design used in the first two experiments in this series with some improvements made in the cable terminations. A guard ring configuration was used on the disk shaped sample. Triaxial mineral insulated cable was used as the data lead from the sputter deposited guard ring and central electrode of the sample, and coaxial mineral insulated cable was used as the sample power lead. No evidence for REID was observed in this series of experiments to a dose level of {approx}1.8 dpa. The effect of neutron irradiation on the electrical properties of two mineral insulated (MgO) cables was also investigated.

  1. 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.

  2. Microstructure, AC impedance and DC electrical conductivity characteristics of NiFe2-xGdxO4 (x = 0, 0.05 and 0.075)

    NASA Astrophysics Data System (ADS)

    Kamala Bharathi, K.; Markandeyulu, G.; Ramana, C. V.

    2012-03-01

    The structure and electrical characteristics of Gd doped Ni ferrite materials, namely NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4, are reported to demonstrate their improved electrical properties compared to that of pure NiFe2O4. NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4 compounds crystallize in the cubic inverse spinel phase with a very small amount of GdFeO3 additional phase while pure NiFe2O4 crystallize in inverse spinel phase without any impurity phase. The back scattered electron imaging analysis indicate the primary and secondary formation in NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4 compounds. Atomic force microscopy measurements indicate that the bulk grains are ˜2-5 micron size while the grain boundaries are thin compared to bulk grains. Impedance spectroscopic analysis at different temperature indicates the different relaxation mechanisms and their variation with temperature, bulk grain and grain-boundary contributions to the electrical conductivity (Rg) and capacitance (Cg) of these materials. The conductivity in pure NiFeO4 is found to be predominantly due to intrinsic bulk contribution (Rg=213 kΩ and Cg=4.5 x 10-8 F). In the case of NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4 compounds, grain and grain-boundary contributions to the conductivity are clearly observed. The DC conductivity values (at 300 K) of NiFe2O4, NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4 compounds are found to be 1.06 x 10-7 Ω-1 cm-1, 5.73 x 10-8 Ω-1 cm-1 and 1.28 x 10-8 Ω-1 cm-1 respectively.

  3. Test Results of Total Ionizing Dose Conducted at the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Rivas, Rosa M.; Johnston, Allan H.; Miyahira, Tetsuo F.; Rax, Bernard G.; Wiedeman, Michael D.

    2004-01-01

    This paper reports recent Total Ionizing Dose (TID) test results obtained at JPL. Several device samples were analyzed exhibiting significant failure levels and ELDRS effects under biased and unbiased condition.

  4. LABORATORY AND FIELD RESULTS LINKING HIGH CONDUCTIVITIES TO THE MICROBIAL DEGRADATION OF PETROLEUM HYDROCARBONS

    EPA Science Inventory

    The results of a field and laboratory investigation of unconsolidated sediments contaminated by petroleum hydrocarbons and undergoing natural biodegradation are presented. Fundamental to geophysical investigations of hydrocarbon impacted sediments is the assessment of how microbi...

  5. Compendium of Test Results of Recent Single Event Effect Tests Conducted by the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    McClure, Steven S.; Allen, Gregory R.; Irom, Farokh; Scheick, Leif Z.; Adell, Philippe C.; Miyahira, Tetsuo F.

    2010-01-01

    This paper reports heavy ion and proton-induced single event effect (SEE) results from recent tests for a variety of microelectronic devices. The compendium covers devices tested over the last two years by the Jet Propulsion Laboratory.

  6. Results of Single-Event Latchup Measurements Conducted by the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Miyahira, Tetsuo F.; Irom, Farokh

    2008-01-01

    This paper reports recent single-event latchup results for a variety of microelectronic devices that include an digital, analog, and CMOS. The data was collected to evaluate these devices for possible use in NASA spacecraft.

  7. Compendium of Recent Test Results of Single Event Effects Conducted by the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Allen, Gregory R.; Guertin, Steven M.; Scheick, Leif Z.; Irom, Farokh; Zajac, Stephanie

    2012-01-01

    This paper reports heavy ion, proton, and laser induced single event effects results for a variety of microelectronic devices targeted for possible use in NASA spacecrafts. The compendium covers devices tested within the years of 2010 through 2012.

  8. LABORATORY AND FIELD RESULTS LINKING HIGH CONDUCTIVITIES TO THE MICROBIAL DEGRADATION OF PETROLEUM HYDROCARBONS

    EPA Science Inventory

    The results of a l6-month field and l6-month meso-scale laboratory investigation of unconsolidated sandy environments contaminated by petroleum hydrocarbons that are undergoing natural biodegradation is presented. The purpose was to understand the processes responsible for causin...

  9. Can Urinary Nitrite Results Be Used to Conduct Antimicrobial Option for Urinary Tract Infection in Children?

    PubMed Central

    Mahyar, Abolfazl; Ayazi, Parviz; Froozesh, Mahta; Daneshi-Kohan, Mohammad-Mahdi; Barikani, Ameneh

    2012-01-01

    Objective This study was performed to determine the relationship between urinary nitrite results and bacterial resistance to antimicrobial drugs in urinary tract infection of children. Methods In a cross-section study 119 children younger than 12 years with urinary tract infection were evaluated in Qazvin children's hospital. Patients were divided into negative and positive nitrite groups depending on urinary nitrite test result. Rates of antibiotic resistance in the two groups were compared. Findings Sixty seven patients were in the negative nitrite group and 52 in the positive nitrite group. Resistance rates to ceftriaxone, trimethoprim sulfamethoxazole, ampicillin, gentamicin, amikacin, nalidixic acid, cephalothin and nitrofurantoin in the nitrite negative group were 7.5%, 31.3%, 50.7%, 11.9%, 9%, 3%, 14.9% and 11.9%, respectively. These values in the nitrite positive group were 21.2%, 28.8%, 63.5%, 7.7%, 5.8%, 1.9%, 9.6%, and 3.8%, respectively (P>0.05). Conclusion This study showed that there is no correlation between urinary nitrite results and bacterial resistance to antimicrobial drugs. Therefore, it seems that physicians should not adjust antibiotic therapy for UTI based on nitrite results. PMID:23056892

  10. Report on Results of Focus Groups Conducted with People with Disabilities.

    ERIC Educational Resources Information Center

    Maine State Dept. of Human Services, Augusta. Bureau of Health.

    This report describes results of six focus groups of people with disabilities convened by the Maine Bureau of Health to determine the feelings, attitudes, and experiences of this population. Four groups were comprised of adults ranging in age from the early twenties to the late seventies; two groups were comprised of adolescents and young adults.…

  11. Results of Single-event Effects Measurements Conducted by the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Irom, Farokh; Miyahira, Tetsuo F.

    2006-01-01

    This paper reports recent single-event effects results for a variety of microelectronic devices that include an ADC, DAC, supervisory circuit, FIFO and a Viterbi decoder. The data was collected to evaluate these devices for possible use in NASA spacecraft.

  12. Results of Single-Event Latchup Measurements Conducted by the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Irom, Farokh; Miyahira, Tetsuo F.

    2010-01-01

    This paper reports recent single-event latchup (SEL) results for a variety of microelectronic devices that include OpAmp, Voltage Reference, Motor Controller, Switch Mode Controller, Resolver-to-Digital Converter and Analog-to-Digital Converter. The data was collected to evaluate these devices for possible use in NASA spacecraft.

  13. Interrelationship between Number of Mobile Protons, Diffusion Coefficient, and AC Conductivity in Superprotonic Conductors, CsHSO4 and Rb3H(SeO4)2

    NASA Astrophysics Data System (ADS)

    Kamazawa, Kazuya; Harada, Masashi; Araki, Toru; Matsuo, Yasumitsu; Tyagi, Madhusudan; Sugiyama, Jun

    2014-07-01

    Using quasielastic neutron scattering (QENS), we investigated the proton dynamics for two superprotonic conductors, CsHSO4 and Rb3H(SeO4)2. To evaluate the self-diffusion coefficients and the number of mobile protons on both superprotonic and normal phases, we focused on proton dynamics not only in the phase above Tc, but also in the phase below Tc. In Rb3H(SeO4)2, the self-diffusion of protons was observed even below the Tc phase. In contrast to popular belief, no large changes in the self-diffusion coefficients were observed across Tc. Nevertheless, the increase in the number of mobile protons across Tc was about 14.5 times, which was estimated from the integrated intensity of QENS spectra, and this change could not account for the increased magnitude of proton conductivity, which is about 500 times. As a large translational self-diffusion coefficient has not been reported in previous works by QENS experiments, there are still unknown factors that contribute to the Nernst-Einstein relation that need to be discovered.

  14. Results of Macroinvertebrate Sampling Conducted at 33 SRS Stream Locations, July--August 1993

    SciTech Connect

    Specht, W.L.

    1994-12-01

    In order to assess the health of the macroinvertebrate communities of SRS streams, the macroinvertebrate communities at 30 stream locations on SRS were sampled during the summer of 1993, using Hester-Dendy multiplate samplers. In addition, three off-site locations in the Upper Three Runs drainage were sampled in order to assess the potential for impact from off-site activities. In interpreting the data, it is important to recognize that these data were from a single set of collections. Macroinvertebrate communities often undergo considerable temporal variation, and are also greatly influenced by such factors as water depth, water velocity, and available habitat. These stations were selected with the intent of developing an on-going sampling program at a smaller number of stations, with the selection of the stations to be based largely upon the results of this preliminary sampling program. When stations within a given stream showed similar results, fewer stations would be sampled in the future. Similarly, if a stream appeared to be perturbed, additional stations or chemical analyses might be added so that the source of the perturbation could be identified. In general, unperturbed streams will contain more taxa than perturbed streams, and the distribution of taxa among orders or families will differ. Some groups of macroinvertebrates, such as Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies), which are collectively called EPT taxa, are considered to be relatively sensitive to most kinds of stream perturbation; therefore a reduced number of EPT taxa generally indicates that the stream has been subject to chemical or physical stressors. In coastal plain streams, EPT taxa are generally less dominant than in streams with rocky substrates, while Chironomidae (midges) are more abundant. (Abstract Truncated)

  15. Results of the pilot proof of the inquiry activities conducted in the science center

    NASA Astrophysics Data System (ADS)

    Kireš, Marián; BilišÅanská, Mária

    2017-01-01

    The science center SteelPARK Košice offers more than 60 interactive exhibits focused on presenting scientific principles and technical solutions connected to the production and manufacture of steel, research of its properties and its various industrial uses. We are trying to enhance the attractivity of the modern style of the exhibitions and its potential to engage students of ground and middle schools in acquiring new knowledge and capabilities, by means of the inquiry science center. Two laboratory measurements, for 5 three-person teams are provided once a month. During the introductory discussion on the activity, they are asked to answer a series of conceptual questions, which help determine their level of understanding at the beginning of the exercise. The measurements are based in guided inquiry, where the work progress is given a forehand, but the desired result is not. Every activity is focused on developing specific research capabilities. This is being monitored through a self-evaluation card, which every participants is required to fill out immediately after completing the activity. The work is tutored by a lecturer from the students of didactics. During two years and running 15 different activities, we have been able to gather information from more than 6000 students of ground and middle schools. Specific physics measurements, their respective conceptual questions, worksheets and final reports are being presented in this article. We evaluate the present level of conceptual understanding based on the acquired data and give recommendation to teachers on ways to improve the student's capabilities. The teacher, by way of observing the activity, the work of the lecturer and the students, is able to form an understanding of the inquiry activity for their own school practice, for which he/she can use all available methodical and work materials.

  16. Principle and experimental results of ultra-wideband noise radar imaging of a cylindrical conducting object using diffraction tomography

    NASA Astrophysics Data System (ADS)

    Shin, Hee Jung; Asmuth, Mark A.; Narayanan, Ram M.; Rangaswamy, Muralidhar

    2015-05-01

    In this paper, the principle, simulation, and experiment results of tomographic imaging of a cylindrical conducting object using random noise waveforms are presented. Theoretical analysis of scattering and the image reconstruction technique are developed based on physical optics approximation and Fourier diffraction tomography, respectively. The bistatic radar system is designed to transmit band-limited ultra-wideband (UWB) random noise waveforms at a fixed position, and a linear scanner allows a single receiving antenna to move along a horizontal axis for backward scattering measurement in the frequency range from 3-5 GHz. The reconstructed tomographic image of the rotating cylindrical conducting object based on experimental results are seen to be in good agreement with the simulation results, which demonstrates the capability of UWB noise radar for complete two-dimensional tomographic image reconstruction of a cylindrical conducting object.

  17. Petrology-based Modeling of Mantle Melt Electrical Conductivity and Joint-Interpretation of Electromagnetic and Seismic Results

    NASA Astrophysics Data System (ADS)

    Pommier, A.; Garnero, E. J.

    2013-12-01

    The presence of melt in the Earth's interior depends on the thermal state, bulk chemistry and dynamics. Therefore, the investigation of the physical and chemical properties of melt is a probe of the planet's structure, dynamics, and potentially evolution. We present a petrology-based model of the electrical conductivity of fertile and depleted peridotites during partial melting. Seismic and magnetotelluric (MT) studies provide geophysical datasets sensitive to the presence of melt, but they do not necessarily agree on melt fraction estimates. A possible explanation regards the assumptions made about melt chemistry as part of MT data interpretation. Melt fraction estimates from electrical anomalies usually assume a basaltic melt phase, whereas petrological studies suggest that the first liquids produced have a different chemistry, and thus a different conductivity. Our model is based on the existing laboratory database of electrical conductivity of silicate melts and crystals, and allows calculation of the electrical conductivity of peridotite partial melting (valid at pressures up to 2 GPa) that accounts for the dependency of melt composition on the extent of melting. Partial melting of both depleted and fertile peridotites is considered. Chemical compositions and phase proportions of melt and crystals are determined using the MELTS algorithm [1]. The melt composition dependence on electrical conductivity is expressed using the optical basicity parameter. Our results show that melts produced by low-degree peridotite melting (< 14 vol. %) are up to 5 times more conductive than basaltic liquids. Such conductive melts significantly affect bulk rock conductivity, particularly for a fertile peridotite. Our findings demonstrate that the electrical conductivity of low-degree partial melting of a peridotite can be significantly underestimated if the liquid phase is assumed to be basaltic, resulting in overestimated melt fractions from bulk conductivity values. Application

  18. Offering parents individualized feedback on the results of psychological testing conducted for research purposes with children: ethical issues and recommendations.

    PubMed

    Lefaivre, Marie-josée; Chambers, Christine T; Fernandez, Conrad V

    2007-01-01

    Research protocols involving children often include psychological testing as part of an assessment battery. Inclusion of such testing raises the question of whether parents (or others) should be offered the individualized results of their children's psychological testing conducted for research purposes. The purpose of this article is to provide a review of the ethical issues and principles associated with individualized feedback of psychological testing conducted for research purposes. Two hypothetical cases are offered to illustrate the complexities of this topic. Detailed recommendations for the management of disclosure of the results of psychological testing in research settings are also proposed.

  19. The problem of illegally induced abortion: results from a hospital-based study conducted at district level in Dar es Salaam.

    PubMed

    Rasch, V; Muhammad, H; Urassa, E; Bergström, S

    2000-07-01

    Illegal abortion is known to be a major contributor to maternal mortality. The objective of the study was firstly to identify women with illegally induced abortion, (IA) and to compare them with women admitted with a spontaneous abortion (SA) or receiving antenatal care (AC), and secondly to describe the circumstances which characterized the abortion. The population of this cross-sectional questionnaire study comprised patients from Temeke District Hospital, Dar es Salaam, Tanzania. After an in-depth confidential interview, 603 women with incomplete abortion were divided into two groups: 362 women with IA and 241 with SA. They were compared with 307 AC women. IA women were significantly younger, more often better educated, unmarried, nulliparous and students than AC women. Regarding civil-status, educational level, proportion of nullipara and proportion of students, SA patients were similar to AC women. These results lend support to the assumption that the in-depth confidential interview made it possible to distinguish IA women from SA women.

  20. Synergistic interactions between Cry1Ac and natural cotton defenses limit survival of Cry1Ac-resistant Helicoverpa zea (Lepidoptera: Noctuidae) on Bt cotton.

    PubMed

    Anilkumar, Konasale J; Sivasupramaniam, Sakuntala; Head, Graham; Orth, Robert; Van Santen, Edzard; Moar, William J

    2009-07-01

    Larvae of the bollworm Helicoverpa zea (Boddie) show some tolerance to Bacillus thuringiensis (Bt) Cry1Ac, and can survive on Cry1Ac-expressing Bt cotton, which should increase resistance development concerns. However, field-evolved resistance has not yet been observed. In a previous study, a population of H. zea was selected for stable resistance to Cry1Ac toxin. In the present study, we determined in laboratory bioassays if larvae of the Cry1Ac toxin-resistant H. zea population show higher survival rates on field-cultivated Bt cotton squares (= flower buds) collected prebloom-bloom than susceptible H. zea. Our results show that Cry1Ac toxin-resistant H. zea cannot complete larval development on Cry1Ac-expressing Bt cotton, despite being more than 150-fold resistant to Cry1Ac toxin and able to survive until pupation on Cry1Ac toxin concentrations greater than present in Bt cotton squares. Since mortality observed for Cry1Ac-resistant H. zea on Bt cotton was higher than expected, we investigated whether Cry1Ac interacts with gossypol and or other compounds offered with cotton powder in artificial diet. Diet incorporation bioassays were conducted with Cry1Ac toxin alone, and with gossypol and 4% cotton powder in the presence and absence of Cry1Ac. Cry1Ac toxin was significantly more lethal to susceptible H. zea than to resistant H. zea, but no difference in susceptibility to gossypol was observed between strains. However, combinations of Cry1Ac with gossypol or cotton powder were synergistic against resistant, but not against susceptible H. zea. Gossypol concentrations in individual larvae showed no significant differences between insect strains, or between larvae fed gossypol alone vs. those fed gossypol plus Cry1Ac. These results may help explain the inability of Cry1Ac-resistant H. zea to complete development on Bt cotton, and the absence of field-evolved resistance to Bt cotton by this pest.

  1. Inclusion of Information Covering Electronic Resources in National Bibliographies: Results of a Survey Conducted May-June 1998.

    ERIC Educational Resources Information Center

    Byrum, John D.

    This paper reports on the results of a survey conducted in spring 1998 to ascertain the extent to which National Bibliographic Agencies (NBAs) were providing coverage of publications in electronic formats. A total of 61 institutions, representing agencies in 59 countries, replied to the questionnaire. NBAs representing 34 countries indicated…

  2. Offering Parents Individualized Feedback on the Results of Psychological Testing Conducted for Research Purposes with Children: Ethical Issues and Recommendations

    ERIC Educational Resources Information Center

    Lefaivre, Marie-josee; Chambers, Christine T.; Fernandez, Conrad V.

    2007-01-01

    Research protocols involving children often include psychological testing as part of an assessment battery. Inclusion of such testing raises the question of whether parents (or others) should be offered the individualized results of their children's psychological testing conducted for research purposes. The purpose of this article is to provide a…

  3. Enhanced Stomatal Conductance by a Spontaneous Arabidopsis Tetraploid, Me-0, Results from Increased Stomatal Size and Greater Stomatal Aperture.

    PubMed

    Monda, Keina; Araki, Hiromitsu; Kuhara, Satoru; Ishigaki, Genki; Akashi, Ryo; Negi, Juntaro; Kojima, Mikiko; Sakakibara, Hitoshi; Takahashi, Sho; Hashimoto-Sugimoto, Mimi; Goto, Nobuharu; Iba, Koh

    2016-03-01

    The rate of gas exchange in plants is regulated mainly by stomatal size and density. Generally, higher densities of smaller stomata are advantageous for gas exchange; however, it is unclear what the effect of an extraordinary change in stomatal size might have on a plant's gas-exchange capacity. We investigated the stomatal responses to CO2 concentration changes among 374 Arabidopsis (Arabidopsis thaliana) ecotypes and discovered that Mechtshausen (Me-0), a natural tetraploid ecotype, has significantly larger stomata and can achieve a high stomatal conductance. We surmised that the cause of the increased stomatal conductance is tetraploidization; however, the stomatal conductance of another tetraploid accession, tetraploid Columbia (Col), was not as high as that in Me-0. One difference between these two accessions was the size of their stomatal apertures. Analyses of abscisic acid sensitivity, ion balance, and gene expression profiles suggested that physiological or genetic factors restrict the stomatal opening in tetraploid Col but not in Me-0. Our results show that Me-0 overcomes the handicap of stomatal opening that is typical for tetraploids and achieves higher stomatal conductance compared with the closely related tetraploid Col on account of larger stomatal apertures. This study provides evidence for whether larger stomatal size in tetraploids of higher plants can improve stomatal conductance.

  4. The Association between Parent-Child Conflict and Adolescent Conduct Problems over Time: Results from a Longitudinal Adoption Study

    PubMed Central

    Klahr, Ashlea M.; McGue, Matt; Iacono, William G.; Burt, S. Alexandra

    2010-01-01

    A handful of prior adoption studies have confirmed that the cross-sectional relationship between child conduct problems and parent/child conflict is at least partially shared environmental in origin. However, as the direction of causation between parenting and delinquency remains unclear, this relationship could be better explained by the adolescent's propensity to elicit conflictive parenting, a phenomenon referred to as an evocative gene-environment correlation. The current study thus examined the prospective relationship between conduct problems and parent-child conflict in a sample of adoptive families. Participants included 672 adolescents in 405 adoptive families assessed at two time points roughly 4 years apart. Results indicated that parent-child conflict predicts the development of conduct problems, whereas conduct problems do not predict increases in parent-child conflict. Such findings suggest that evocative gene-environment correlations are highly unlikely as an explanation of prior shared environmental effects during adolescence. Moreover, because the adolescents in this study do not share genes with their adoptive parents, the association between conduct problems and parent-child conflict is indicative of shared environmental mediation in particular. Implications of our findings are discussed. PMID:21038930

  5. The association between parent-child conflict and adolescent conduct problems over time: results from a longitudinal adoption study.

    PubMed

    Klahr, Ashlea M; McGue, Matt; Iacono, William G; Burt, S Alexandra

    2011-02-01

    A handful of prior adoption studies have confirmed that the cross-sectional relationship between child conduct problems and parent-child conflict at least partially originates in the shared environment. However, as the direction of causation between parenting and delinquency remains unclear, this relationship could be better explained by the adolescent's propensity to elicit conflictive parenting, a phenomenon referred to as an evocative gene-environment correlation. In the current study, the authors thus examined the prospective relationship between conduct problems and parent-child conflict in a sample of adoptive families. Participants included 672 adolescents in 405 adoptive families assessed at 2 time points roughly 4 years apart. Results indicated that parent-child conflict predicts the development of conduct problems, whereas conduct problems do not predict increases in parent-child conflict. Such findings suggest that evocative gene-environment correlations are highly unlikely to be an explanation of prior shared environmental effects during adolescence. Moreover, because the adolescents in this study do not share genes with their adoptive parents, the association between conduct problems and parent-child conflict is indicative of shared environmental mediation in particular. Implications of the findings are discussed.

  6. Study of AC/RF properties of SRF ingot niobium

    SciTech Connect

    Dhakal, Pashupati; Tsindlekht, Menachem I; Genkin, Valery M; Ciovati, Gianluigi; Myneni, Ganapati Rao

    2013-09-01

    In an attempt to correlate the performance of superconducting radiofrequency cavities made of niobium with the superconducting properties, we present the results of the magnetization and ac susceptibility of the niobium used in the superconducting radiofrequency cavity fabrication. The samples were subjected to buffer chemical polishing (BCP) surface and high temperature heat treatments, typically applied to the cavities fabrications. The analysis of the results show the different surface and bulk ac conductivity for the samples subjected to BCP and heat treatment. Furthermore, the RF surface impedance is measured on the sample using a TE011 microwave cavity for a comparison to the low frequency measurements.

  7. AC electrophoretic deposition of organic-inorganic composite coatings.

    PubMed

    Yoshioka, T; Chávez-Valdez, A; Roether, J A; Schubert, D W; Boccaccini, A R

    2013-02-15

    Alternating current electrophoretic deposition (AC-EPD) of polyacrylic acid (PAA)-titanium oxide (TiO(2)) nanoparticle composites on stainless steel electrodes was investigated in basic aqueous solution. AC square wave with duty cycle of 80% was applied at a frequency of 1 kHz. FTIR-ATR spectra showed that both AC and direct current (DC) EPD successfully deposited PAA-TiO(2) composites. The deposition rate using AC-EPD was lower than that obtained in direct current DC-EPD. However, the microstructure and surface morphology of the deposited composite coatings were different depending on the type of electric field applied. AC-EPD applied for not more than 5 min led to smooth films without bubble formation, while DC-EPD for 1 min or more showed deposits with microstructural defects possibly as result of water electrolysis. AC-EPD was thus for the first time demonstrated to be a suitable technique to deposit organic-inorganic composite coatings from aqueous suspensions, showing that applying a square wave and frequency of 1 kHz leads to uniform PAA-TiO(2) composite coatings on conductive materials.

  8. Simultaneous distribution of AC and DC power

    DOEpatents

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  9. Real-ear measurements in conductive hearing loss: discrepancies between probe-tube microphone measurements and sound field test results.

    PubMed

    Cleaver, V C

    1998-06-01

    This study was designed to investigate earlier observations that probe-tube microphone measurements of insertion gain overestimates the functional gain received from hearing aids by users with significant conductive hearing losses. This was originally thought to be due to artefacts in the probe-tube measurement caused by middle ear pathology, but is now believed to be the result of the bone conduction stimulation of the ear exposed to high intensities of airborne sound during sound field threshold measurements. Since the functional gain must relate to the true aided benefit in such cases, these findings suggest that probe-tube microphone measurements in ears with significant air-bone gaps should be interpreted with caution.

  10. Analytical results of a long-term aquifer test conducted near the Rio Grande, Albuquerque, New Mexico, with a section on piezometric-extensometric test results

    USGS Publications Warehouse

    Thorn, Conde R.; Heywood, Charles E.

    2001-01-01

    The City of Albuquerque, New Mexico, is interested in gaining a better understanding, both quantitative and qualitative, of the aquifer system in and around Albuquerque. Currently (2000), the City of Albuquerque and surrounding municipalities are completely dependent on ground-water reserves for their municipal water supply. This report presents the results of a long-term aquifer test conducted near the Rio Grande in Albuquerque. The long-term aquifer test was conducted during the winter of 1994-95. The City of Albuquerque Griegos 1 water production well was pumped continuously for 54 days at an average pumping rate of 2,331 gallons per minute. During the 54-day pumping and a 30-day recovery period, water levels were recorded in a monitoring network that consisted of 3 production wells and 19 piezometers located at nine sites. These wells and piezometers were screened in river alluvium and (or) the upper and middle parts of the Santa Fe Group aquifer system. In addition to the measurement of water levels, aquifer-system compaction was monitored during the aquifer test by an extensometer. Well-bore video and flowmeter surveys were conducted in the Griegos 1 water production well at the end of the recovery period to identify the location of primary water- producing zones along the screened interval. Analytical results from the aquifer test presented in this report are based on the methods used to analyze a leaky confined aquifer system and were performed using the computer software package AQTESOLV. Estimated transmissivities for the Griegos 1 and 4 water production wells ranged from 10,570 to 24,810 feet squared per day; the storage coefficient for the Griegos 4 well was 0.0025. A transmissivity of 13,540 feet squared per day and a storage coefficient of 0.0011 were estimated from the data collected from a piezometer completed in the production interval of the Griegos 1 well.

  11. Dynamics of lamin A/C in porcine embryos produced by nuclear transfer.

    PubMed

    Lee, Kiho; Fodor, William L; Machaty, Zoltan

    2007-09-01

    This study was conducted to investigate the presence of lamin A/C in porcine nuclear transfer embryos and to determine whether lamin A/C can serve as a potential marker for nuclear reprogramming. First, lamin A/C was studied in oocytes and embryos produced by fertilization or parthenogenetic oocyte activation. We found that lamin A/C was present in the nuclear lamina of oocytes at the germinal vesicle stage while it was absent in mature oocytes. Lamin A/C was detected throughout preimplantation development in both in vivo-derived and parthenogenetic embryos. Incubation of the activated oocytes in the presence of alpha-amanitin (an inhibitor of RNA polymerase II), or cycloheximide (a protein synthesis inhibitor) did not perturb lamin A/C assembly, indicating that the assembly resulted from solubilized lamins dispersed in the cytoplasm. In nuclear transfer embryos, the lamin A/C signal that had previously been identified in fibroblast nuclei disappeared soon after fusion. It became detectable again after the formation of the pronucleus-like structure, and all nuclear transfer embryos displayed lamin A/C staining during early development. Olfactory bulb progenitor cells lacked lamin A/C; however, when such cells were fused with enucleated oocytes, the newly formed nuclear envelopes stained positive for lamin A/C. These findings suggest that recipient oocytes remodel the donor nuclei using type A lamins dispersed in the ooplasm. The results also indicate that lamin A/C is present in the nuclear envelope of pig oocytes and early embryos and unlike in some other species, its presence after nuclear transfer is not an indicator of erroneous reprogramming.

  12. Results From a Pressure Sensitive Paint Test Conducted at the National Transonic Facility on Test 197: The Common Research Model

    NASA Technical Reports Server (NTRS)

    Watkins, A. Neal; Lipford, William E.; Leighty, Bradley D.; Goodman, Kyle Z.; Goad, William K.; Goad, Linda R.

    2011-01-01

    This report will serve to present results of a test of the pressure sensitive paint (PSP) technique on the Common Research Model (CRM). This test was conducted at the National Transonic Facility (NTF) at NASA Langley Research Center. PSP data was collected on several surfaces with the tunnel operating in both cryogenic mode and standard air mode. This report will also outline lessons learned from the test as well as possible approaches to challenges faced in the test that can be applied to later entries.

  13. New levitation scheme with AC superconducting magnet for EDS MAGLEV system

    SciTech Connect

    Kim, D.H.; Lee, J.K.; Hahn, S.Y.; Cha, G.

    1996-09-01

    This paper proposes a new magnetic levitation scheme which is able to generate levitation force for all speeds including a standstill. Auxiliary wheels which are needed in EDS MAGLEV vehicle can be eliminated. This scheme uses AC superconducting magnets to generate levitation force. In this paper, magnetic fields, forces and power dissipations generated by AC magnets moving above a conducting slab are calculated analytically. Results of calculation show characteristics of EDS system with AC magnet, such as levitation force and loss, are superior to those of EDS system with DC magnets for all speeds.

  14. ACS after SM4: On-orbit Verification of the HST Advanced Camera for Surveys Repair

    NASA Astrophysics Data System (ADS)

    Golimowski, David A.; Cheng, E. S.; Loose, M.; Sirianni, M.; Lupie, O. L.; Smith, L. J.; Arslanian, S.; Boyce, K. R.; Chapman, G.; Chiaberge, M.; Desjardins, T.; Dye, D.; Ellis, T.; Grogin, N. A.; Lim, P.; Lucas, R. A.; Maybhate, A.; Mil, K. J.; Mutchler, M.; Ricardo, R.; Scott, B.; Serrano, B.; Suchkov, A.; Waczynski, A.; Welty, A. D.; Wheeler, T.; Wilson, E.

    2010-01-01

    The newly replaced CCD electronics box (CEB-R) of the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) features a programmable SIDECAR ASIC manufactured by Teledyne. The CEB-R not only restores the functionality of the ACS Wide Field Camera (WFC), but it allows optimization of the WFC's imaging performance via on-orbit adjustment of CCD bias and clock voltages and serial-data transmission timing. We describe the strategy, preparation, execution, and results of the ACS Optimization Campaign, an unprecedented on-orbit extension of ground-based integration and testing that was conducted during the HST Servicing Mission Observatory Verification period.

  15. PS2-45: Conducting Multi-site Quality Assurance on Laboratory Results Data Incorporated into the Virtual Data Warehouse

    PubMed Central

    Saylor, Gwyn; Bredfeldt, Christine; Butler, Melissa; Folck, Bruce; Hitz, Paul; Krajenta, Richard; Ogarek, Jessica; Ovans, Lucas; Pardee, Roy; Riedlinger, Karen; Schmidt, Mark; Sterrett, Andrew; Raebel, Marsha

    2012-01-01

    Background/Aims Assuring that complete and correct laboratory test results are brought into the VDW and associated with the correct Test_Type is an ongoing task. Many problems can occur. For example, a particular version of a test can incorrectly be left out when the data are extracted. Results can be duplicated, or results can be associated incorrectly with a Test_Type. Creating quality assurance checks to locate problems or validate data requires evaluating the same data record from several different angles. Methods We conducted quality assurance on numerous laboratory test results that had been incorporated into VDW format across as many as 11 HMORN sites. Quality assurance programs were written to provide counts of test results across sites and over time. These programs also detailed result values, result units, patient location, result location, and other specific metrics. Descriptive statistics and graphical displays were used to facilitate assessment of across-site data variability and identify potential data quality issues. Sites were provided their site-specific results and results for all participating sites. Results Masking site information, we will show examples of quality assurance checks and depict what type of problem each is designed to point out. Examples may include incorrectly mapped tests (e.g., “hemoglobin” test results where the result unit was in percent and was determined to actually be glycosylated hemoglobin results) and tests that require investigation by the site because the result unit is possible, but unusual (e.g., total cholesterol units of g/dl require verification of g/dl unit and conversion to mg/dl before use or verification that g/dl was entered or read incorrectly). Other examples can include the volume of test results now contained within the VDW (e.g., total cholesterol total n is over 26.6 million results). Conclusions Laboratory result quality assurance requires assessment of problems as well as verifying expectations

  16. Temperature dependence of dc electrical conductivity of activated carbon-metal oxide nanocomposites. Some insight into conduction mechanisms

    NASA Astrophysics Data System (ADS)

    Barroso-Bogeat, Adrián; Alexandre-Franco, María; Fernández-González, Carmen; Sánchez-González, José; Gómez-Serrano, Vicente

    2015-12-01

    From a commercial activated carbon (AC) and six metal oxide (Al2O3, Fe2O3, SnO2, TiO2, WO3 and ZnO) precursors, two series of AC-metal oxide nanocomposites are prepared by wet impregnation, oven-drying at 120 °C, and subsequent heat treatment at 200 or 850 °C in inert atmosphere. The temperature-dependent dc electrical conductivity of AC and the as-prepared nanocomposites is measured from room temperature up to ca. 200 °C in air atmosphere by the four-probe method. The decrease in conductivity for the hybrid materials as compared to AC is the result of a complex interplay between several factors, including not only the intrinsic conductivity, crystallite size, content and chemical nature of the supported nanoparticles, which ultimately depend on the precursor and heat treatment temperature, but also the adsorption of oxygen and water from the surrounding atmosphere. The conductivity data are discussed in terms of a thermally activated process. In this regard, both AC and the prepared nanocomposites behave as semiconductors, and the temperature-dependent conductivity data have been interpreted on the basis of the classical model proposed by Mott and Davis. Because of its high content of heteroatoms, AC may be considered as a heavily doped semiconductor, so that conduction of thermally excited carriers via acceptor or donor levels is expected to be the dominant mechanism. The activation energies for the hybrid materials suggest that the supported metal oxide nanoparticles strongly modify the electronic band structure of AC by introducing new trap levels in different positions along its band gap. Furthermore, the thermally activated conduction process satisfies the Meyer-Neldel rule, which is likely connected with the shift of the Fermi level due to the introduction of the different metal oxide nanoparticles in the AC matrix.

  17. Results and analyses for irradiation/anneal experiments conducted on Yankee Rowe reactor pressure vessel surrogate materials. Final report

    SciTech Connect

    Biemiller, E.C.

    1995-12-01

    The Yankee Atomic Electric Company test irradiation program was implemented to characterize the irradiation response of representative Yankee Rowe reactor vessel beltline plate and weld materials and to remove uncertainties in the analysis of existing irradiation data on the Yankee Rowe reactor vessel steel. The effect of plate nickel content and microstructure on irradiation damage sensitivity was assessed. Typical reactor vessel plate materials each containing 0.24% (by weight) copper, but different nickel contents at 0.63% and 0.19%, were heat treated to produce different microstructures in the test materials. A Linde 80 weld containing 0.30% copper and 1.00% nickel was produced and heat treated to test microstructure effects on the irradiation response of weld metal. Materials taken from plate surface locations (vs 1/4 thickness) were included to test whether or not the improved toughness properties of the plate surface layer, resulting from a rapid quench, is maintained after irradiation. Irradiations were conducted at two irradiation temperatures (500{degrees}F and 550{degrees}F) to determine the effect of irradiation temperature on embrittlement. An annealing test matrix was also initiated to study the potential for a 650{degrees}F anneal. A major irradiation/annealing/reirradiation study was conducted by the DOE`s LWR Technology Center at Sandia National Laboratories (SNL), using an irradiation temperature of 550{degrees}F and a 850{degrees}F anneal. The results of the irradiation testing and the DOE/SNL annealing study show an irradiation temperature effect that is not consistent but, varies with the materials tested. The test results demonstrate that for nickel bearing steels, the superior toughness of plate surface material is maintained even after irradiation to high fluences and for the copper content tested, nickel has little effect on irradiation response.

  18. Database dictionary for the results of groundwater tracer tests using tritiated water, conducted at the Oak Ridge National Laboratory

    SciTech Connect

    Thompson, B.K.; Huff, D.D.

    1997-05-01

    In 1977, the United States Geological Survey (USGS) conducted two tracer tests at the Oak Ridge National Laboratory (ORNL) using tritiated water to study the relative importance of bedding-plane openings on shallow groundwater flow. Through a cooperative agreement between the USGS and the US Department of Energy (DOE), the data were made available to researchers at the Oak Ridge National Laboratory (ORNL), who organized the data into a data management format. The results of these groundwater tracer tests have been compiled into a collection of four SAS data sets. This report documents these SAS data sets, including their structure, methodology, and content. The SAS data sets include information on precipitation, tritium, water levels, and well construction for wells at or near ORNL radioactive waste burial grounds 4, 5, and 6.

  19. Numbness after Transradial Cardiac Catheterization: the Results from a Nerve Conduction Study of the Superficial Radial Nerve

    PubMed Central

    Jang, Ho-Jun; Kim, Ji-Young; Han, Jae Deok; Lee, Hyun Jong; Kim, Je Sang; Park, Jin Sik; Choi, Rak Kyeong; Choi, Young Jin; Shim, Won-Heum; Kwon, Sung Woo

    2016-01-01

    Background and Objectives Numbness on the hand occurs infrequently after a transradial cardiac catheterization (TRC). The symptom resembles that of neuropathy. We, therefore, investigated the prevalence, the predicting factors and the presence of neurological abnormalities of numbness, using a nerve conduction study (NCS). Subjects and Methods From April to December 2013, all patients who underwent a TRC were prospectively enrolled. From among these, the patients who experienced numbness on the ipsilateral hand were instructed to describe their symptoms using a visual analogue scale; subsequently, NCSs were performed on these patients. Results Of the total 479 patients in the study sample, numbness occurred in nine (1.8%) following the procedure. The NCS was performed for eight out of the nine patients, four (50%) of which had an abnormal NCS result at the superficial radial nerve. A larger sheath and history of myocardial infarction (p=0.14 and 0.08 respectively) tended towards the occurrence of numbness; however, only the use of size 7 French sheaths was an independent predictor for the occurrence of numbness (odds ratio: 5.50, 95% confidence interval: 1.06-28.58, p=0.042). The symptoms disappeared for all patients but one, within four months. Conclusion A transient injury of the superficial radial nerve could be one reason for numbness after a TRC. A large sheath size was an independent predictor of numbness; therefore, large sized sheaths should be used with caution when performing a TRC. PMID:27014346

  20. Smoking Status and the Five-Factor Model of Personality: Results of a Cross-Sectional Study Conducted in Poland

    PubMed Central

    Buczkowski, Krzysztof; Basinska, Małgorzata A.; Ratajska, Anna; Lewandowska, Katarzyna; Luszkiewicz, Dorota; Sieminska, Alicja

    2017-01-01

    Tobacco smoking is the single most important modifiable factor in increased morbidity and premature mortality. Numerous factors—including genetics, personality, and environment—affect the development and persistence of tobacco addiction, and knowledge regarding these factors could improve smoking cessation rates. This study compared personality traits between never, former, and current smokers, using the Five-Factor Model of Personality in a country with a turbulent smoking reduction process.: In this cross-sectional study, 909 Polish adults completed the Revised Neuroticism-Extraversion-Openness Personality Inventory. Our results showed that current smokers’ scores for extraversion, one of the five global dimensions of personality, were higher relative to never smokers. Neuroticism, openness to experience, agreeableness, and conscientiousness did not differ significantly according to smoking status. Facet analysis, which described each dimension in detail, showed that current smokers’ activity and excitement seeking (facets of extraversion) scores were higher relative to those of never and former smokers. In turn, current smokers’ dutifulness and deliberation (facets of conscientiousness) scores were lower than those found in former and never smokers. Never smokers scored the highest in self-consciousness (a facet of neuroticism) and compliance (a component of agreeableness). The study conducted among Polish individuals showed variation in personality traits according to their smoking status; however, this variation differed from that reported in countries in which efforts to reduce smoking had begun earlier relative to Poland. Knowledge regarding personality traits could be useful in designing smoking prevention and cessation programs tailored to individuals’ needs. PMID:28134805

  1. Smoking Status and the Five-Factor Model of Personality: Results of a Cross-Sectional Study Conducted in Poland.

    PubMed

    Buczkowski, Krzysztof; Basinska, Małgorzata A; Ratajska, Anna; Lewandowska, Katarzyna; Luszkiewicz, Dorota; Sieminska, Alicja

    2017-01-27

    Tobacco smoking is the single most important modifiable factor in increased morbidity and premature mortality. Numerous factors-including genetics, personality, and environment-affect the development and persistence of tobacco addiction, and knowledge regarding these factors could improve smoking cessation rates. This study compared personality traits between never, former, and current smokers, using the Five-Factor Model of Personality in a country with a turbulent smoking reduction process.: In this cross-sectional study, 909 Polish adults completed the Revised Neuroticism-Extraversion-Openness Personality Inventory. Our results showed that current smokers' scores for extraversion, one of the five global dimensions of personality, were higher relative to never smokers. Neuroticism, openness to experience, agreeableness, and conscientiousness did not differ significantly according to smoking status. Facet analysis, which described each dimension in detail, showed that current smokers' activity and excitement seeking (facets of extraversion) scores were higher relative to those of never and former smokers. In turn, current smokers' dutifulness and deliberation (facets of conscientiousness) scores were lower than those found in former and never smokers. Never smokers scored the highest in self-consciousness (a facet of neuroticism) and compliance (a component of agreeableness). The study conducted among Polish individuals showed variation in personality traits according to their smoking status; however, this variation differed from that reported in countries in which efforts to reduce smoking had begun earlier relative to Poland. Knowledge regarding personality traits could be useful in designing smoking prevention and cessation programs tailored to individuals' needs.

  2. Effect of the magnetic material on AC losses in HTS conductors in AC magnetic field carrying AC transport current

    NASA Astrophysics Data System (ADS)

    Wan, Xing-Xing; Huang, Chen-Guang; Yong, Hua-Dong; Zhou, You-He

    2015-11-01

    This paper presents an investigation on the AC losses in several typical superconducting composite conductors using the H-formulation model. A single superconducting strip with ferromagnetic substrate or cores and a stack of coated conductors with ferromagnetic substrates are studied. We consider all the coated conductors carrying AC transport currents and simultaneously exposed to perpendicular AC magnetic fields. The influences of the amplitude, frequency, phase difference and ferromagnetic materials on the AC losses are investigated. The results show that the magnetization losses of single strip and stacked strips have similar characteristics. The ferromagnetic substrate can increase the magnetization loss at low magnetic field, and decrease the loss at high magnetic field. The ferromagnetic substrate can obviously increase the transport loss in stacked strips. The trends of total AC losses of single strip and stacked strips are similar when they are carrying current or exposed to a perpendicular magnetic field. The effect of the frequency on the total AC losses of single strip is related to the amplitude of magnetic field. The AC losses decrease with increasing frequency in low magnetic field region while increase in high magnetic field region. As the phase difference changes, there is a periodic variation for the AC losses. Moreover, when the strip is under only the transport current and magnetic field, the ferromagnetic cores will increase the AC losses for large transport current or field.

  3. AC Optimal Power Flow

    SciTech Connect

    2016-10-04

    In this work, we have implemented and developed the simulation software to implement the mathematical model of an AC Optimal Power Flow (OPF) problem. The objective function is to minimize the total cost of generation subject to constraints of node power balance (both real and reactive) and line power flow limits (MW, MVAr, and MVA). We have currently implemented the polar coordinate version of the problem. In the present work, we have used the optimization solver, Knitro (proprietary and not included in this software) to solve the problem and we have kept option for both the native numerical derivative evaluation (working satisfactorily now) as well as for analytical formulas corresponding to the derivatives being provided to Knitro (currently, in the debugging stage). Since the AC OPF is a highly non-convex optimization problem, we have also kept the option for a multistart solution. All of these can be decided by the user during run-time in an interactive manner. The software has been developed in C++ programming language, running with GCC compiler on a Linux machine. We have tested for satisfactory results against Matpower for the IEEE 14 bus system.

  4. ACS: ALMA Common Software

    NASA Astrophysics Data System (ADS)

    Chiozzi, Gianluca; Šekoranja, Matej

    2013-02-01

    ALMA Common Software (ACS) provides a software infrastructure common to all ALMA partners and consists of a documented collection of common patterns and components which implement those patterns. The heart of ACS is based on a distributed Component-Container model, with ACS Components implemented as CORBA objects in any of the supported programming languages. ACS provides common CORBA-based services such as logging, error and alarm management, configuration database and lifecycle management. Although designed for ALMA, ACS can and is being used in other control systems and distributed software projects, since it implements proven design patterns using state of the art, reliable technology. It also allows, through the use of well-known standard constructs and components, that other team members whom are not authors of ACS easily understand the architecture of software modules, making maintenance affordable even on a very large project.

  5. Effect of adverse childhood experiences on physical health in adulthood: Results of a study conducted in Baghdad city

    PubMed Central

    Al-Shawi, Ameel F.; Lafta, Riyadh K.

    2015-01-01

    Background: Studies have revealed a powerful relationship between adverse childhood experiences (ACEs) and physical and mental health in adulthood. Literature documents the conversion of traumatic emotional experiences in childhood into organic disease later in life. Objective: The aim was to estimate the effect of childhood experiences on the physical health of adults in Baghdad city. Subjects and Methods: A cross-sectional study was conducted from January 2013 to January 2014. The study sample was drawn from Baghdad city. Multistage sampling techniques were used in choosing 13 primary health care centers and eight colleges of three universities in Baghdad. In addition, teachers of seven primary schools and two secondary schools were chosen by a convenient method. Childhood experiences were measured by applying a modified standardized ACEs-International Questionnaire form and with questions for bonding to family and parental monitoring. Physical health assessment was measured by a modified questionnaire derived from Health Appraisal Questionnaire of Centers for Disease Control and Prevention. The questionnaire includes questions on cerebrovascular diseases, diabetes mellitus, tumor, respiratory and gastrointestinal diseases. Results: Logistic regression model showed that a higher level of bonding to family (fourth quartile) is expected to reduce the risk of chronic physical diseases by almost the half (odds ratio = 0.57) and exposure to a high level of household dysfunction and abuse (fourth quartile) is expected to increase the risk of chronic physical diseases by 81%. Conclusion: Childhood experiences play a major role in the determination of health outcomes in adulthood, and early prevention of ACEs. Encouraging strong family bonding can promote physical health in later life. PMID:25983602

  6. RHIC spin flipper AC dipole controller

    SciTech Connect

    Oddo, P.; Bai, M.; Dawson, C.; Gassner, D.; Harvey, M.; Hayes, T.; Mernick, K.; Minty, M.; Roser, T.; Severino, F.; Smith, K.

    2011-03-28

    The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to and dynamically tune the magnets. The current implementation and results will be presented. Work on a new spin flipper for RHIC (Relativistic Heavy Ion Collider) incorporating multiple dynamically tuned high-Q AC-dipoles has been developed for RHIC spin-physics experiments. A spin flipper is needed to cancel systematic errors by reversing the spin direction of the two colliding beams multiple times during a store. The spin flipper system consists of four DC-dipole magnets (spin rotators) and five AC-dipole magnets. Multiple AC-dipoles are needed to localize the driven coherent betatron oscillation inside the spin flipper. Operationally the AC-dipoles form two swept frequency bumps that minimize the effect of the AC-dipole dipoles outside of the spin flipper. Both AC bumps operate at the same frequency, but are phase shifted from each other. The AC-dipoles therefore require precise control over amplitude and phase making the implementation of the AC-dipole controller the central challenge.

  7. Optical conductivity from pair density waves

    NASA Astrophysics Data System (ADS)

    Dai, Zhehao; Lee, Patrick A.

    2017-01-01

    We present a theory of optical conductivity in systems with finite-momentum Cooper pairs. In contrast to the BCS pairing where ac conductivity is purely imaginary in the clean limit, there is nonzero ac absorption across the superconducting gap for finite-momentum pairing if we break the Galilean symmetry explicitly in the electronic Hamiltonian. Vertex correction is crucial for maintaining the gauge invariance in the mean-field formalism and dramatically changes the optical conductivity in the direction of the pairing momentum. We carried out a self-consistent calculation and gave an explicit formula for optical conductivity in a simple case. This result applies to the Fulde-Ferrell-Larkin-Ovchinnikov state and candidates with pair density waves proposed for high-Tc cuprates. It may help detect pair density waves and determine the pairing gap as well as the direction of the pairing momentum in experiments.

  8. 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.

  9. E-Learning in European Higher Education Institutions: Results of a Mapping Survey Conducted in October-December 2013

    ERIC Educational Resources Information Center

    Gaebel, Michael; Kupriyanova, Veronika; Morais, Rita; Colucci, Elizabeth

    2014-01-01

    The present study on e-learning intends to contribute to closing a data gap and to stimulate the discussion on the further development of national and European policies on the issue and to support its systematic institutional take-up. It draws upon a survey conducted by the European University Association between October and December 2013. 249…

  10. A Portrait of the Audience for Instruction in Web Searching: Results of a Survey Conducted at Two Canadian Universities.

    ERIC Educational Resources Information Center

    Tillotson, Joy

    2003-01-01

    Describes a survey that was conducted involving participants in the library instruction program at two Canadian universities in order to describe the characteristics of students receiving instruction in Web searching. Examines criteria for evaluating Web sites, search strategies, use of search engines, and frequency of use. Questionnaire is…

  11. Detection of internal insects in wheat using a conductive roller mill and estimation of insect fragments in the resulting flour

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A laboratory roller mill that monitors the conductance of kernels that pass through it was tested for its ability to estimate the number of insect fragments in flour after milling. This system can test a kilogram of whole wheat in approximately one minute and requires little sample preparation. Ha...

  12. Current Models of Digital Scholarly Communication: Results of an Investigation Conducted by Ithaka for the Association of Research Libraries

    ERIC Educational Resources Information Center

    Maron, Nancy L.; Smith, K. Kirby

    2008-01-01

    As electronic resources for scholarship proliferate, more and more scholars turn to their computers rather than to print sources to conduct their research. The decentralized distribution of these new model works can make it difficult to fully appreciate their scope and number, even for university librarians tasked with knowing about valuable…

  13. Frequency-dependent conductivity in bismuth-vanadate glassy semiconductors

    NASA Astrophysics Data System (ADS)

    Ghosh, Aswini

    1990-01-01

    The first measurements are reported for the frequency-dependent (ac) conductivity (real as well as imaginary parts) for various compositions of the bismuth-vanadate glassy semiconductors in the frequency range 102-105 Hz and in the temperature range 77-420 K. The behavior of the ac conductivity is broadly similar to what has been observed previously in many other types of amorphous semiconductors, namely, nearly linear frequency dependence and weak temperature dependence. The experimental results are analyzed with reference to various theoretical models based on quantum-mechanical tunneling and classical hopping over barriers. The analysis shows that the temperature dependence of the ac conductivity is consistent with the simple quantum-mechanical tunneling model at low temperatures; however, this model completely fails to predict the observed temperature dependence of the frequency exponent. The overlapping-large-polaron tunneling model can explain the temperature dependence of the frequency exponent at low temperatures. Fitting of this model to the low-temperature data yields a reasonable value of the wave-function decay constant. However, this model predicts the temperature dependence of the ac conductivity much higher than what actual data showed. The correlated barrier hopping model is consistent with the temperature dependence of both the ac conductivity and its frequency exponent. This model provides reasonable values of the maximum barrier heights but higher values of characteristic relaxation times.

  14. Abscisic Acid Antagonizes Ethylene Production through the ABI4-Mediated Transcriptional Repression of ACS4 and ACS8 in Arabidopsis.

    PubMed

    Dong, Zhijun; Yu, Yanwen; Li, Shenghui; Wang, Juan; Tang, Saijun; Huang, Rongfeng

    2016-01-04

    Increasing evidence has revealed that abscisic acid (ABA) negatively modulates ethylene biosynthesis, although the underlying mechanism remains unclear. To identify the factors involved, we conducted a screen for ABA-insensitive mutants with altered ethylene production in Arabidopsis. A dominant allele of ABI4, abi4-152, which produces a putative protein with a 16-amino-acid truncation at the C-terminus of ABI4, reduces ethylene production. By contrast, two recessive knockout alleles of ABI4, abi4-102 and abi4-103, result in increased ethylene evolution, indicating that ABI4 negatively regulates ethylene production. Further analyses showed that expression of the ethylene biosynthesis genes ACS4, ACS8, and ACO2 was significantly decreased in abi4-152 but increased in the knockout mutants, with partial dependence on ABA. Chromatin immunoprecipitation-quantitative PCR assays showed that ABI4 directly binds the promoters of these ethylene biosynthesis genes and that ABA enhances this interaction. A fusion protein containing the truncated ABI4-152 peptide accumulated to higher levels than its full-length counterpart in transgenic plants, suggesting that ABI4 is destabilized by its C terminus. Therefore, our results demonstrate that ABA negatively regulates ethylene production through ABI4-mediated transcriptional repression of the ethylene biosynthesis genes ACS4 and ACS8 in Arabidopsis.

  15. Mild Traumatic Brain Injury and Conduction Aphasia from a Close Proximity Blast Resulting in Arcuate Fasciculus Damage Diagnosed on DTI Tractography

    DTIC Science & Technology

    2009-11-01

    Conduction Aphasia from a Close Proximity Blast Resulting in Arcuate Fasciculus Damage Diagnosed on DTI Tractography Guarantor: J. Wesson Ashford...November 2009 issue. 1 The authors present a case demonstrating that a blast injury was associated with both conduction aphasia and an abnormality in...study demonstrating that damage to the AF is associated with conduction aphasia .2 Based on the patient’s length of posttraumatic amnesia this

  16. The AC-120: The advanced commercial transport

    NASA Technical Reports Server (NTRS)

    Duran, David; Griffin, Ernest; Mendoza, Saul; Nguyen, Son; Pickett, Tim; Noernberg, Clemm

    1993-01-01

    The main objective of this design was to fulfill a need for a new airplane to replace the aging 100 to 150 passenger, 1500 nautical mile range aircraft such as the Douglas DC9 and Boeing 737-100 airplanes. After researching the future aircraft market, conducting extensive trade studies, and analysis on different configurations, the AC-120 Advanced Commercial Transport final design was achieved. The AC-120's main design features include the incorporation of a three lifting surface configuration which is powered by two turboprop engines. The AC-120 is an economically sensitive aircraft which meets the new FM Stage Three noise requirements, and has lower NO(x) emissions than current turbofan powered airplanes. The AC-120 also improves on its contemporaries in passenger comfort, manufacturing, and operating cost.

  17. Prevalence, symptoms and chronicity of ciguatera in New Caledonia: results from an adult population survey conducted in Noumea during 2005.

    PubMed

    Baumann, Francine; Bourrat, Marie-Blanche; Pauillac, Serge

    2010-10-01

    Ciguatera is a widespread ichthyosarcotoxism which causes gastrointestinal, neurological and cardiovascular disturbances. Investigations conducted by ORSTOM in 1992 highlighted a prevalence of 25% in the adult population of Noumea, New Caledonia. The main objective of our study was to estimate the prevalence of ciguatera and the persistence of symptoms by sex and by ethnicity among adult patients of a nurse clinic in Noumea in 2005. Investigations were conducted from 1st January to 15th June 2005. During this period, 559 patients were included: 165 males and 394 females. Among them, 37.8% were poisoned at least once in their life. This rate was independent of gender and ethnicity, but was significantly higher in age groups above 40 years. Neurological signs were more frequent (>80%) than gastrointestinal (<50%) and cardiac signs (<15%). Symptoms presented no difference between ethnic or gender groups, even for subjective signs. Most of poisonings were due to carnivorous fishes, but quite all species living in the lagoon were quoted. Symptoms persisted more than one year for 34% of the population, in both Melanesians and Caucasians. This study shows a significant increase of ciguatera prevalence, and its chronicity for 1/5 of European cases.

  18. Instantaneous velocity measurement of AC electroosmotic flows by laser induced fluorescence photobleaching anemometer with high temporal resolution

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Yang, Fang; Qiao, Rui; Wang, Guiren; Rui Qiao Collaboration

    2015-11-01

    Understanding the instantaneous response of flows to applied AC electric fields may help understand some unsolved issues in induced-charge electrokinetics and enhance performance of microfluidic devices. Since currently available velocimeters have difficulty in measuring velocity fluctuations with frequency higher than 1 kHz, most experimental studies so far focus only on the average velocity measurement in AC electrokinetic flows. Here, we present measurements of AC electroosmotic flow (AC-EOF) response time in microchannels by a novel velocimeter with submicrometer spatial resolution and microsecond temporal resolution, i.e. laser-induced fluorescence photobleaching anemometer (LIFPA). Several parameters affecting the AC-EOF response time to the applied electric signal were investigated, i.e. channel length, transverse position and solution conductivity. The experimental results show that the EOF response time under a pulsed electric field decreases with the reduction of the microchannel length, distance between the detection position to the wall and the conductivity of the solution. This work could provide a new powerful tool to measure AC electrokinetics and enhance our understanding of AC electrokinetic flows.

  19. Late gadolinium enhanced cardiovascular magnetic resonance of lamin A/C gene mutation related dilated cardiomyopathy

    PubMed Central

    2011-01-01

    Background The purpose of this study was to identify early features of lamin A/C gene mutation related dilated cardiomyopathy (DCM) with cardiovascular magnetic resonance (CMR). We characterise myocardial and functional findings in carriers of lamin A/C mutation to facilitate the recognition of these patients using this method. We also investigated the connection between myocardial fibrosis and conduction abnormalities. Methods Seventeen lamin A/C mutation carriers underwent CMR. Late gadolinium enhancement (LGE) and cine images were performed to evaluate myocardial fibrosis, regional wall motion, longitudinal myocardial function, global function and volumetry of both ventricles. The location, pattern and extent of enhancement in the left ventricle (LV) myocardium were visually estimated. Results Patients had LV myocardial fibrosis in 88% of cases. Segmental wall motion abnormalities correlated strongly with the degree of enhancement. Myocardial enhancement was associated with conduction abnormalities. Sixty-nine percent of our asymptomatic or mildly symptomatic patients showed mild ventricular dilatation, systolic failure or both in global ventricular analysis. Decreased longitudinal systolic LV function was observed in 53% of patients. Conclusions Cardiac conduction abnormalities, mildly dilated LV and depressed systolic dysfunction are common in DCM caused by a lamin A/C gene mutation. However, other cardiac diseases may produce similar symptoms. CMR is an accurate tool to determine the typical cardiac involvement in lamin A/C cardiomyopathy and may help to initiate early treatment in this malignant familiar form of DCM. PMID:21689390

  20. NASA Desert RATS 2010: Preliminary Results for Science Operations Conducted in the San Francisco Volcanic Field, Arizona

    NASA Technical Reports Server (NTRS)

    Gruener, J. E.; Lofgren, G. E.; Bluethmann, W. J.; Bell, E. R.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) is working with international partners to develop the space architectures and mission plans necessary for human spaceflight beyond earth orbit. These mission plans include the exploration of planetary surfaces with significant gravity fields. The Apollo missions to the Moon demonstrated conclusively that surface mobility is a key asset that improves the efficiency of human explorers on a planetary surface. NASA's Desert Research and Technology Studies (Desert RATS) is a multi-year series tests of hardware and operations carried out annually in the high desert of Arizona. Conducted since 1998, these activities are designed to exercise planetary surface hardware and operations in relatively harsh climatic conditions where long-distance, multi-day roving is achievable

  1. Results of an interlaboratory fatigue test program conducted on alloy 800H at room and elevated temperatures

    NASA Technical Reports Server (NTRS)

    Ellis, J. R.

    1985-01-01

    The experimental approach adopted for low cycle fatigue tests of alloy 800H involved the use of electrohydraulic test systems, hour glass geometry specimens, diametral extensometers, and axial strain computers. Attempts to identify possible problem areas were complicated by the lack of reliable data for the heat of Alloy 800H under investigation. The method adopted was to generate definitive test data in an Interlaboratory Fatigue Test Program. The laboratories participating in the program were Argonne National Laboratory, Battelle Columbus, Mar-Test, and NASA Lewis. Fatigue tests were conducted on both solid and turbular specimens at temperatures of 20, 593, and 760 C and strain ranges of 2.0, 1.0, and 0.5 percent. The subject test method can, under certain circumstances, produce fatigue data which are serious in error. This approach subsequently was abandoned at General Atomic Company in favor of parallel gage length specimens and axial extensiometers.

  2. 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.

  3. Electrothermally driven flows in ac electrowetting.

    PubMed

    García-Sánchez, Pablo; Ramos, Antonio; Mugele, Frieder

    2010-01-01

    Mixing within sessile drops can be enhanced by generating internal flow patterns using ac electrowetting. While for low ac frequencies, the flow patterns have been attributed to oscillations of the drop surface, we provide here the driving mechanism of the hitherto unexplained high-frequency flows. We show that: (1) the electric field in the liquid bulk becomes important, leading to energy dissipation due to Joule heating and a temperature increase of several degrees Celsius, and (2) the fluid flow at these frequencies is generated by electrothermal effect, i.e., gradients in temperature give rise to gradients in conductivity and permittivity, the electric field acting on these inhomogeneities induces an electrical body force that generates the flow. We solved numerically the equations for the electric, temperature and flow fields. The temperature is obtained from a convection-diffusion equation where Joule heating is introduced as a source term. From the solution of the electric field and the temperature, we compute the electrical force that acts as a body force in Stokes equations. Our numerical results agree with previous experimental observations.

  4. NASA Desert RATS 2010: Preliminary results for science operations conducted in the San Francisco Volcanic Field, Arizona

    NASA Astrophysics Data System (ADS)

    Gruener, J. E.; Lofgren, G. E.; Bluethmann, W. J.; Abercromby, A. F.

    2013-10-01

    The National Aeronautics and Space Administration (NASA) is working with international partners to develop the space architectures and mission plans necessary for human spaceflight beyond Earth orbit. The Apollo missions to the Moon demonstrated conclusively that surface mobility is a key asset that improves the efficiency of human explorers on a planetary surface. NASA's Desert Research and Technology Studies (Desert RATS), a multi-year series of tests of hardware and operations carried out annually in the high desert of Arizona, has tested a crewed pressurized rover concept referred to as the Space Exploration Vehicle (SEV). During NASA's Desert RATS 2010, four 2-person crews driving two SEVs collectively conducted 12 days of field exploration in the San Francisco Volcanic Field in northern Arizona. They collected 461 samples, with a total mass of 161.2 kg, on 70 simulated extravehicular activities (EVAs). Each SEV crew traveled over 60 km during their field explorations. This paper illustrates where the actual field sites, or 'science stations', were located, provides a brief description of the types of samples collected at each station, and highlights some of the more interesting sites. Most of the geologic samples collected at Desert RATS 2010 were well documented at the site of collection, and upon delivery to the Johnson Space Center the samples were given a preliminary examination. The samples are available for further study by interested researchers developing scientific instruments for use on the surfaces of the Moon and Mars, or for geological investigations of the San Francisco Volcanic Field.

  5. 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.

  6. Continuous-function ground conductivity model for the determination of electric railway earth conductance

    SciTech Connect

    Carpenter, D.C. ); Hill, R.J. . School of Electronic and Electrical Engineering)

    1993-09-01

    A method is described for the determination of ground conductivity as a continuous function of depth and frequency for applications along spatially linear structures such as railway tracks. The technique involves measurements of mutual resistance using a modified dipole array excited with AC currents up to audio frequency. After representation of the experimental data by analytic functions, the ground conductivity-depth variation is obtained as a degenerate hypergeometric function. The determined ground conductivity is utilized to model the self and mutual conductance of and between the running rails in a single-track railway. The result is verified by experimental measurement.

  7. Conductivity tensor of graphene dominated by spin-orbit coupling scatterers: A comparison between the results from Kubo and Boltzmann transport theories.

    PubMed

    Liu, Zhe; Jiang, Liwei; Zheng, Yisong

    2016-03-31

    The diagonal and Hall conductivities of graphene arising from the spin-orbit coupling impurity scattering are theoretically studied. Based on the continuous model, i.e. the massless Dirac equation, we derive analytical expressions of the conductivity tensor from both the Kubo and Boltzmann transport theories. By performing numerical calculations, we find that the Kubo quantum transport result of the diagonal conductivity within the self-consistent Born approximation exhibits an insulating gap around the Dirac point. And in this gap a well-defined quantized spin Hall plateau occurs. This indicates the realization of the quantum spin Hall state of graphene driven by the spin-orbit coupling impurities. In contrast, the semi-classical Boltzmann theory fails to predict such a topological insulating phase. The Boltzmann diagonal conductivity is nonzero even in the insulating gap, in which the Boltzmann spin Hall conductivity does not exhibit any quantized plateau.

  8. Conductivity tensor of graphene dominated by spin-orbit coupling scatterers: A comparison between the results from Kubo and Boltzmann transport theories

    PubMed Central

    Liu, Zhe; Jiang, Liwei; Zheng, Yisong

    2016-01-01

    The diagonal and Hall conductivities of graphene arising from the spin-orbit coupling impurity scattering are theoretically studied. Based on the continuous model, i.e. the massless Dirac equation, we derive analytical expressions of the conductivity tensor from both the Kubo and Boltzmann transport theories. By performing numerical calculations, we find that the Kubo quantum transport result of the diagonal conductivity within the self-consistent Born approximation exhibits an insulating gap around the Dirac point. And in this gap a well-defined quantized spin Hall plateau occurs. This indicates the realization of the quantum spin Hall state of graphene driven by the spin-orbit coupling impurities. In contrast, the semi-classical Boltzmann theory fails to predict such a topological insulating phase. The Boltzmann diagonal conductivity is nonzero even in the insulating gap, in which the Boltzmann spin Hall conductivity does not exhibit any quantized plateau. PMID:27029398

  9. Prognostic value of Muc5AC in gastric cancer: A meta-analysis

    PubMed Central

    Zhang, Chuan-Tao; He, Ke-Cheng; Pan, Fei; Li, Yuan; Wu, Jiang

    2015-01-01

    AIM: To assess the correlation between decreased Muc5AC expression and patients’ survival and clinicopathological characteristics by conducting a meta-analysis. METHODS: Literature searches were performed in PubMed and EMBASE, and 11 studies met our criteria. Summary hazard ratios or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the effect. For the pooled analysis of the correlation between decreased Muc5AC expression and clinicopathological characteristics (tumour invasion depth, lymph node metastasis, tumour-node-metastasis stage, tumour size, venous invasion and lymphatic invasion), ORs and their variance were combined to estimate the effect. RESULTS: Eleven retrospective cohort studies comprising 2135 patients were included to assess the association between Muc5AC expression and overall survival and/or clinicopathological characteristics. Decreased Muc5AC expression was significantly correlated with poor overall survival of gastric cancer patients (pooled HR = 1.35, 95%CI: 1.08-1.7). Moreover, decreased Muc5AC expression was also significantly associated with tumour invasion depth (pooled OR = 2.12, 95%CI: 1.56-2.87) and lymph node metastasis (pooled OR = 1.56, 95%CI: 1.00-2.44) in gastric cancer. CONCLUSION: Decreased Muc5AC expression might be a poor prognostic predictor for gastric cancer. PMID:26420972

  10. [The results of research conducted at the Stefan S. Nicolau Institute of Virology on the herpes simplex virus].

    PubMed

    Muţiu, A

    1989-01-01

    The report is a review of the research and results of the "Stefan S. Nicolau" Institute of Virology scientists in the field of herpes viruses, as they were materialized in the great number of published or communicated scientific papers these last ten years.

  11. Modifying rib rail placement for the powered roll gin stand: Results from studies conducted on a retrofitted Lummus gin stand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The powered roll gin stand (PRGS) is a technology that has shown evidence of improving ginning rate, turnout, and fiber quality. However, results from the numerous studies comparing the technology against the conventional gin stand has given rise to speculation that the technology is only fitting fo...

  12. Comparing audiological test results obtained from a sound processor attached to a Softband with direct and magnetic passive bone conduction hearing implant systems.

    PubMed

    Kara, Ahmet; Iseri, Mete; Durgut, Merve; Topdag, Murat; Ozturk, Murat

    2016-12-01

    The aim of this study was to compare audiological test results obtained from a sound processor (SP) attached to a Softband with those obtained from direct (abutment connection) bone conduction implant systems and magnetic passive bone conduction implant systems with different magnet strengths on patients implanted at our clinic. Twenty-four patients who were implanted with either an abutment or magnetic bone conduction implant system between January 2012 and December 2014 were analyzed for hearing results, such as free-field hearing thresholds, direct bone conduction hearing thresholds, and speech discrimination scores with aided and unaided conditions Both magnetic and direct osseointegrated bone conduction implant systems, as well as the Softband system, provide good hearing outcomes when compared with unaided performance; however, the abutment connection system gives better hearing thresholds in the higher frequencies. No significant difference in hearing gain was found between the Softband system, magnet 5, and magnet used by the patient. Magnetic and direct bone conduction hearing implant systems are both effective for rehabilitation of conductive and mixed hearing loss when conventional hearing aids cannot be used. However, patients with high-frequency hearing loss may be better suited to an abutment connection system if they are not satisfied with high-frequency hearing gains provided via the trial Softband system preoperatively and should be counseled accordingly.

  13. Transport AC losses of Ag-sheathed Bi-2223 tapes with different twist-pitch using electrical methods

    NASA Astrophysics Data System (ADS)

    Jang, M.-H.; Wong-Ng, W.

    2006-01-01

    A series of Bi-2223 ([Bi, Pb]:Sr:Ca:Cu:O = 2:2:2:3) tapes with 37 superconducting core filaments was investigated in an attempt to correlate critical current and alternating current (AC) losses with twist-pitch. The twist-pitch of these multi-filamentary tapes which were produced by the powder-in-(Ag)tube (PIT) method varies from 8, 10, 13, 30, 50, 70 mm to ∞ mm (non-twist). Critical current (Ic) measurements which were conducted in zero field by a four-probe method under liquid-nitrogen temperature showed that Ic is greater in the non-twist filament than that in twisted filaments. Among these tapes, three (twist-pitch of 10, 13, and 70 mm) were selected for AC loss experiments under a time-varying transport current. The results of AC loss measurements in general agree with that of the AC loss simulation using the ellipse model of the Norris equation. Simulation results show that the hysteretic AC loss is lowest in the non-twist tape and increases as the twist-pitch decreases. A much greater loss was found in tapes with small twist-pitch, i.e. 10 and 8 mm. Among different possible loss contributions to the total AC losses, the hysteretic loss was determined to be the main source. In addition, microstructural damage of tapes with small twist-pitch appears to contribute to the overall AC losses as well.

  14. [A double-blind nomifensine-nortriptyline trial in ambulatory patients conducted by psychiatrists in private practice: results and comments].

    PubMed

    Coudray, J P; Dufour, H; Garello, J L; Mollo, Y; Pascal, F; Poisson, D; Scotto, J C; Simart, G; Sormani, J; Tourame, G

    1978-06-28

    Nomifensine and nortriptyline were compared in a collaborative trial by psychiatrists in private practice. The trial impiled:--selection of ambulatory depressed patients--randomization in parallel groups (respectively 31 and 34 subjects)--administration in double-blind condition of 4 capsuels daily of either compound during 4 weeks--quotation of depressvie syndrom with Hamilton depression scale before treatment after 2 and 4 weeks. The analysis of results shows clear improvment of depression scores, equivalent in both groups (non significant difference and posterior rejection of an alternative hypothesis). Practical problems encountered in controlled trials in psychiatrist's outpatients are discussed.

  15. Basic results of the medical research conducted during the flight of two crews on the Salyut-5 orbital station

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The study of the effect of space factors, especially weightlessness, on man, taking into account prophylactic measures and devices to counteract that effect was part of the program for two flights on the Salyut 5 orbital station. Information from the equipment on board was transmitted telemetrically including: an electrocardiogram; a sphygmogram of carotid and femoral arteries; a kinetocardiogram; a tacho-oscillogram of the humeral artery, perimetric oscillations of the femur, venous pulse and pressure in the jugular veins, vital capacity of the lungs, respiration rate and lung ventilation. Stress factors, metabolism, biological and bacteriological and other tests were included. A comparison was made between these data and pre- and postflight test result.

  16. ac electroosmosis in rectangular microchannels.

    PubMed

    Campisi, Michele; Accoto, Dino; Dario, Paolo

    2005-11-22

    Motivated by the growing interest in ac electroosmosis as a reliable no moving parts strategy to control fluid motion in microfluidic devices for biomedical applications, such as lab-on-a-chip, we study transient and steady-state electrokinetic phenomena (electroosmosis and streaming currents) in infinitely extended rectangular charged microchannels. With the aid of Fourier series and Laplace transforms we provide a general formal solution of the problem, which is used to study the time-dependent response to sudden ac applied voltage differences in case of finite electric double layer. The Debye-Huckel approximation has been adopted to allow for an algebraic solution of the Poisson-Boltzmann problem in Fourier space. We obtain the expressions of flow velocity profiles, flow rates, streaming currents, as well as expressions of the complex hydraulic and electrokinetic conductances. We analyze in detail the dependence of the electrokinetic conductance on the extension of linear dimensions relative to the Debye length, with an eye on finite electric double layer effects.

  17. ac electroosmosis in rectangular microchannels

    NASA Astrophysics Data System (ADS)

    Campisi, Michele; Accoto, Dino; Dario, Paolo

    2005-11-01

    Motivated by the growing interest in ac electroosmosis as a reliable no moving parts strategy to control fluid motion in microfluidic devices for biomedical applications, such as lab-on-a-chip, we study transient and steady-state electrokinetic phenomena (electroosmosis and streaming currents) in infinitely extended rectangular charged microchannels. With the aid of Fourier series and Laplace transforms we provide a general formal solution of the problem, which is used to study the time-dependent response to sudden ac applied voltage differences in case of finite electric double layer. The Debye-Hückel approximation has been adopted to allow for an algebraic solution of the Poisson-Boltzmann problem in Fourier space. We obtain the expressions of flow velocity profiles, flow rates, streaming currents, as well as expressions of the complex hydraulic and electrokinetic conductances. We analyze in detail the dependence of the electrokinetic conductance on the extension of linear dimensions relative to the Debye length, with an eye on finite electric double layer effects.

  18. Results.

    ERIC Educational Resources Information Center

    Zemsky, Robert; Shaman, Susan; Shapiro, Daniel B.

    2001-01-01

    Describes the Collegiate Results Instrument (CRI), which measures a range of collegiate outcomes for alumni 6 years after graduation. The CRI was designed to target alumni from institutions across market segments and assess their values, abilities, work skills, occupations, and pursuit of lifelong learning. (EV)

  19. Chemical Results of Laboratory Dry/Rewet Experiments Conducted on Wetland Soils from Two Sites in the Everglades, Florida

    USGS Publications Warehouse

    Orem, William H.

    2008-01-01

    Drought and fire are natural environmental factors that have historically impacted and shaped the Everglades ecosystem. For example, drought and fire help to maintain the existing ecosystem biotic assemblage by periodically eradicating invading flora not adapted to living with this normal aspect of Everglades' ecology. Flora native to the Everglades are adapted to withstand normal drought cycles and all but the most intense fire conditions that burn into the peat substrate. Remobilization of nutrients and other elements from wetland soil following drought/fire and rewetting may actually stimulate plant re-growth, assisting in the recovery of the ecosystem from these events, and play a role in maintaining the geochemical balance of the ecosystem. Although drought/fire cycles occur naturally in the Everglades' ecosystem, the frequency, intensity, and duration of these events have been altered by anthropogenic activities. The hydrology of the ecosystem has been changed by the construction of water management structures starting around 1900 and continuing through the 1970s. These structures include canals, levees, and pumping stations around Lake Okeechobee and within the Everglades. In addition, water management practices have preferentially moved water toward agricultural and urban areas and away from the Everglades during periods of low rainfall. One result of these practices has been more severe drought and fire cycles within the ecosystem compared to pre-development activity. A major goal of restoration efforts in the Everglades is to restore a more natural flow of water into the ecosystem to alleviate some of the extreme drought and fire conditions witnessed during the past several decades.

  20. Round-robin test on thermal conductivity measurement of ZnO nanofluids and comparison of experimental results with theoretical bounds.

    PubMed

    Lee, Wook-Hyun; Rhee, Chang-Kyu; Koo, Junemo; Lee, Jaekeun; Jang, Seok Pil; Choi, Stephen Us; Lee, Ki-Woong; Bae, Hwa-Young; Lee, Gyoung-Ja; Kim, Chang-Kyu; Hong, Sung Wook; Kwon, Younghwan; Kim, Doohyun; Kim, Soo Hyung; Hwang, Kyo Sik; Kim, Hyun Jin; Ha, Hyo Jun; Lee, Seung-Hyun; Choi, Chul Jin; Lee, Ji-Hwan

    2011-03-25

    Ethylene glycol (EG)-based zinc oxide (ZnO) nanofluids containing no surfactant have been manufactured by one-step pulsed wire evaporation (PWE) method. Round-robin tests on thermal conductivity measurements of three samples of EG-based ZnO nanofluids have been conducted by five participating labs, four using accurate measurement apparatuses developed in house and one using a commercial device. The results have been compared with several theoretical bounds on the effective thermal conductivity of heterogeneous systems. This study convincingly demonstrates that the large enhancements in the thermal conductivities of EG-based ZnO nanofluids tested are beyond the lower and upper bounds calculated using the models of the Maxwell and Nan et al. with and without the interfacial thermal resistance.

  1. Round-robin test on thermal conductivity measurement of ZnO nanofluids and comparison of experimental results with theoretical bounds

    NASA Astrophysics Data System (ADS)

    Lee, Wook-Hyun; Rhee, Chang-Kyu; Koo, Junemo; Lee, Jaekeun; Jang, Seok Pil; Choi, Stephen Us; Lee, Ki-Woong; Bae, Hwa-Young; Lee, Gyoung-Ja; Kim, Chang-Kyu; Hong, Sung Wook; Kwon, Younghwan; Kim, Doohyun; Kim, Soo Hyung; Hwang, Kyo Sik; Kim, Hyun Jin; Ha, Hyo Jun; Lee, Seung-Hyun; Choi, Chul Jin; Lee, Ji-Hwan

    2011-12-01

    Ethylene glycol (EG)-based zinc oxide (ZnO) nanofluids containing no surfactant have been manufactured by one-step pulsed wire evaporation (PWE) method. Round-robin tests on thermal conductivity measurements of three samples of EG-based ZnO nanofluids have been conducted by five participating labs, four using accurate measurement apparatuses developed in house and one using a commercial device. The results have been compared with several theoretical bounds on the effective thermal conductivity of heterogeneous systems. This study convincingly demonstrates that the large enhancements in the thermal conductivities of EG-based ZnO nanofluids tested are beyond the lower and upper bounds calculated using the models of the Maxwell and Nan et al. with and without the interfacial thermal resistance.

  2. Nonlinear alternating current conduction in polycrystalline manganites

    SciTech Connect

    Ghosh, T. N.; Nandi, U. N.; Jana, D.; Dey, K.; Giri, S.

    2014-06-28

    The real part of ac conductance Σ(T, f) of yttrium-doped mixed-valent polycrystalline manganite systems La{sub 1−x−y}Y{sub y}Ca{sub x}MnO{sub 3} with x = 0.33 and 0.05 and y = 0.07 and iron doped LaMn{sub 1−x}Fe{sub x}O{sub 3} with x = 0.15 is measured as a function of frequency f by varying zero-frequency Ohmic conductance Σ{sub 0} by T. The former shows a metal-insulator transition, whereas the latter exhibits insulating character throughout the measured temperature range. At a fixed temperature T, Σ(T, f) remains almost constant to the value Σ{sub 0} up to a certain frequency, known as the onset frequency f{sub c} and increases from Σ{sub 0} as frequency is increased from f{sub c}. Scaled appropriately, the data for Σ(T, f) at different T fall on the same universal curve, indicating the existence of a general scaling formalism for the ac conductance. f{sub c} scales with Σ{sub 0} as f{sub c}∼Σ{sub 0}{sup x{sub f}}, where x{sub f} is the nonlinearity exponent characterising the onset. With the help of data for ac conduction, it is shown that x{sub f} is very much phase sensitive and can be used to characterize the different phases in a manganite system originated due to change in temperature or disorder. Scaling theories and existing theoretical models are used to analyze the results of ac conduction and the nonlinearity exponent x{sub f}.

  3. The Effects of the Toxic Cyanobacterium Limnothrix (Strain AC0243) on Bufo marinus Larvae

    PubMed Central

    Daniels, Olivia; Fabbro, Larelle; Makiela, Sandrine

    2014-01-01

    Limnothrix (strain AC0243) is a cyanobacterium, which has only recently been identified as toxin producing. Under laboratory conditions, Bufo marinus larvae were exposed to 100,000 cells mL−1 of Limnothrix (strain AC0243) live cultures for seven days. Histological examinations were conducted post mortem and revealed damage to the notochord, eyes, brain, liver, kidney, pancreas, gastrointestinal tract, and heart. The histopathological results highlight the toxicological impact of this strain, particularly during developmental stages. Toxicological similarities to β-N-Methylamino-l-alanine are discussed. PMID:24662524

  4. ACS CCDs daily monitor

    NASA Astrophysics Data System (ADS)

    Sirianni, Marco

    2006-07-01

    This program consists of a set of basic tests to monitor, the read noise, thedevelopment of hot pixels and test for any source of noise in ACS CCDdetectors. The files, biases and dark will be used to create referencefiles for science calibration. This programme will be for the entire lifetime of ACS.For cycle 15 the program will cover 18 months 12.1.06->05.31.08and it has been divied into three different proposal each covering six months.The three poroposal are 11041-11042-11043.

  5. 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.

  6. Attitudes of Youth Toward Military Service: A Comparison of Results of National Surveys Conducted in May 1971 and November 1971. Consulting Report.

    ERIC Educational Resources Information Center

    Fisher, Allan H., Jr.

    A comparative analysis of two surveys conducted in May 1971 and November 1971 to gather information on the attitudes of young male civilians (between 16-21 years) towards the military service is presented. Information was collected through interviews with 2,845 individuals in May and 1,960 individuals in November. The results of the surveys are…

  7. AC/DC converter

    NASA Astrophysics Data System (ADS)

    Jain, Praveen K.

    1992-08-01

    In a system such as a 20 kHz space station primary electrical power distribution system, power conversion from AC to DC is required. Some of the basic requirements for this conversion are high efficiency, light weight and small volume, regulated output voltage, close to unity input power factor, distortionless input current, soft-starting, low electromagnetic interference, and high reliability. An AC-to-DC converter is disclosed which satisfies the main design objectives of such converters for use in space. The converter of the invention comprises an input transformer, a resonant network, a current controller, a diode rectifier, and an output filter. The input transformer is for connection to a single phase, high frequency, sinusoidal waveform AC voltage source and provides a matching voltage isolating from the AC source. The resonant network converts this voltage to a sinusoidal, high frequency bidirectional current output, which is received by the current controller to provide the desired output current. The diode rectifier is connected in parallel with the current controller to convert the bidirectional current into a unidirectional current output. The output filter is connected to the rectifier to provide an essentially ripple-free, substantially constant voltage DC output.

  8. 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.

  9. Conformational influence on the hopping conductivity in pig insulin

    NASA Astrophysics Data System (ADS)

    Ye, Yuan-Jie; Ladik, János

    1995-05-01

    The ac conductivity of pig insulin has been reported previously [Y.-J. Ye and J. Ladik, Phys. Rev. B 48, 5120 (1993); Int. J. Quantum Chem. 52, 491 (1994)]. Now we have calculated in the ab initio scheme using Clementi's minimal basis set and the random-walk theory of Lax and co-workers the ac conductivity in another conformation that occurs in the same crystal. The results confirm the conclusions of the previous papers, that is, native proteins can be good amorphous semiconductors if they are doped. The comparison of the results of the two conformations of pig insulin shows that the ac conductivity changes two orders of magnitude in the frequency range that corresponds to the time period of the elementary steps of chemical reactions (ω>1010 sec-1) when the three-dimensional structure changes. However, it does not change significantly in the low-frequency range (ω<104 sec-1). The conclusion is that in the high-frequency range insulin would change both the ac conductivity of itself and its receptor if it binds to a receptor. Thus insulin might change the electron transport in the receptor when it expresses its biological activity.

  10. Ion transport study in polymer-nanocomposite films by dielectric spectroscopy and conductivity scaling

    NASA Astrophysics Data System (ADS)

    Tripathi, Namrata; Thakur, Awalendra K.; Shukla, Archana; Marx, David T.

    2015-07-01

    The dielectric and conductivity response of polymer nanocomposite electrolytes (films of PMMA4LiClO4 dispersed with nano-CeO2 powder) have been investigated. The dielectric behavior was analyzed via the dielectric permittivity (ε‧) and dissipation factor (tan δ) of the samples. The analysis has shown the presence of space charge polarization at lower frequencies. The real part of ac conductivity spectra of materials obeys the Jonscher power law. Parameters such as dc conductivity, hopping rate, activation energies and the concentration of charge carriers were determined from conductivity data using the Almond West formalism. It is observed that the higher ionic conductivity at higher temperature is due to increased thermally-activated hopping rates accompanied by a significant increase in carrier concentration. The contribution of carrier concentration to the total conductivity is also confirmed from activation energy of migration conduction and from Summerfield scaling. The ac conductivity results are also well correlated with TEM results.

  11. Bi-directional flow induced by an AC electroosmotic micropump with DC voltage bias.

    PubMed

    Islam, Nazmul; Reyna, Jairo

    2012-04-01

    This paper discusses the principle of biased alternating current electroosmosis (ACEO) and its application to move the bulk fluid in a microchannel, as an alternative to mechanical pumping methods. Previous EO-driven flow research has looked at the effect of electrode asymmetry and transverse traveling wave forms on the performance of electroosmotic pumps. This paper presents an analysis that was conducted to assess the effect of combining an AC signal with a DC (direct current) bias when generating the electric field needed to impart electroosmosis (EO) within a microchannel. The results presented here are numerical and experimental. The numerical results were generated through simulations performed using COMSOL 3.5a. Currently available theoretical models for EO flows were embedded in the software and solved numerically to evaluate the effects of channel geometry, frequency of excitation, electrode array geometry, and AC signal with a DC bias on the flow imparted on an electrically conducting fluid. Simulations of the ACEO flow driven by a constant magnitude of AC voltage over symmetric electrodes did not indicate relevant net flows. However, superimposing a DC signal over the AC signal on the same symmetric electrode array leads to a noticeable net forward flow. Moreover, changing the polarity of electrical signal creates a bi-directional flow on symmetrical electrode array. Experimental flow measurements were performed on several electrode array configurations. The mismatch between the numerical and experimental results revealed the limitations of the currently available models for the biased EO. However, they confirm that using a symmetric electrode array excited by an AC signal with a DC bias leads to a significant improvement in flow rates in comparison to the flow rates obtained in an asymmetric electrode array configuration excited just with an AC signal.

  12. Enhanced Stomatal Conductance by a Spontaneous Arabidopsis Tetraploid, Me-0, Results from Increased Stomatal Size and Greater Stomatal Aperture1[OPEN

    PubMed Central

    Monda, Keina; Araki, Hiromitsu; Kuhara, Satoru; Ishigaki, Genki; Akashi, Ryo; Negi, Juntaro; Kojima, Mikiko; Sakakibara, Hitoshi; Takahashi, Sho; Hashimoto-Sugimoto, Mimi; Goto, Nobuharu; Iba, Koh

    2016-01-01

    The rate of gas exchange in plants is regulated mainly by stomatal size and density. Generally, higher densities of smaller stomata are advantageous for gas exchange; however, it is unclear what the effect of an extraordinary change in stomatal size might have on a plant’s gas-exchange capacity. We investigated the stomatal responses to CO2 concentration changes among 374 Arabidopsis (Arabidopsis thaliana) ecotypes and discovered that Mechtshausen (Me-0), a natural tetraploid ecotype, has significantly larger stomata and can achieve a high stomatal conductance. We surmised that the cause of the increased stomatal conductance is tetraploidization; however, the stomatal conductance of another tetraploid accession, tetraploid Columbia (Col), was not as high as that in Me-0. One difference between these two accessions was the size of their stomatal apertures. Analyses of abscisic acid sensitivity, ion balance, and gene expression profiles suggested that physiological or genetic factors restrict the stomatal opening in tetraploid Col but not in Me-0. Our results show that Me-0 overcomes the handicap of stomatal opening that is typical for tetraploids and achieves higher stomatal conductance compared with the closely related tetraploid Col on account of larger stomatal apertures. This study provides evidence for whether larger stomatal size in tetraploids of higher plants can improve stomatal conductance. PMID:26754665

  13. AC losses of single-core MgB2 wires with different metallic sheaths

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    AC losses of single-core MgB2 superconductors with different metallic sheaths (Cu, GlidCop, stainless steel and Monel) have been measured and analyzed. These wires were exposed to external magnetic field with frequencies 72 and 144 Hz and amplitudes up to 0.1 T at temperatures ranged from 18 to 40 K. The obtained results have shown that applied metallic sheath can affect the measured AC loss considerably. In the case of GlidCop and Stainless Steel a negligible small effect of metallic sheath was observed. Strong contribution of eddy currents has been found in the wire with well conductive copper sheath. In the case of Monel sheath, the hysteresis loss of magnetic sheath is dominated and AC loss of MgB2 core is practically not visible.

  14. Increased Long-Flight Activity Triggered in Beet Armyworm by Larval Feeding on Diet Containing Cry1Ac Protoxin

    PubMed Central

    Jiang, Xing Fu; Chen, Jian; Zhang, Lei; Sappington, Thomas W.; Luo, Li Zhi

    2013-01-01

    Evaluating ecological safety and conducting pest risk analysis for transgenic crops are vitally important before their commercial planting. The beet armyworm, Spodoptera exigua, a long-distance migratory insect pest, is not a direct target of transgenic Cry1Ac-expressing cotton in China, but nevertheless it has recently become an important pest. Migrants leaving their natal field arrive in other appropriate habitat far away in a short time, often followed by larval outbreaks. S. exigua has low susceptibility to Cry1Ac. However, our results from laboratory experiments identified (i) sublethal effects of Cry1Ac protoxin on larval development rate, larval and pupal weight, and adult lifetime fecundity, and (ii) increased long-flight behavior triggered by Cry1Ac which may contribute to larval outbreaks elsewhere. No significant differences in larval mortality, pupation rate, adult emergence rate, longevity, pre-oviposition period, or oviposition period were observed between controls and larvae fed on artificial diet incorporating a low concentration of Cry1Ac protoxin. The negative sublethal effects on some developmental and reproductive traits and lack of effect on others suggest they do not contribute to the observed severity of S. exigua outbreaks after feeding on Cry1Ac cotton. Interestingly, the percentage of long fliers increased significantly when larvae were reared on diet containing either of two low-dose treatments of Cry1Ac, suggesting a possible increased propensity to disperse long distances triggered by Cry1Ac. We hypothesize that negative effects on development and reproduction caused by Cry1Ac in the diet are offset by increased flight propensity triggered by the poor food conditions, thereby improving the chances of escaping adverse local conditions before oviposition. Increased long-flight propensity in turn may amplify the area damaged by outbreak populations. This phenomenon might be common in other migratory insect pests receiving sublethal doses

  15. Evaluation of modern IGBT-modules for hard-switched AC/DC/AC converters

    SciTech Connect

    Blaabjerg, F.; Pedersen, J.K.; Jaeger, U.

    1995-12-31

    The development of IGBT devices is still producing faster devices with lower losses. The applications become more advanced like a complete hard-switched AC/DC/AC converter with almost clean input current and regenerating capabilities. This paper will first focus on a detailed characterization and comparison of eight different IGBT-modules representing state-of-the-art for both PT and NPT technologies. The voltage level of the devices is 1,200V and 1,600V/1,700V. The characterization is done on an advanced measurement system which is briefly described. The characterization is based on static and dynamic tests for both IGBT and the diodes in the IGBT-modules at a junction temperature at 125 C. The comparison is first done directly based on conduction losses and switching losses, and later the measurements are used in a loss model for a complete AC/DC/AC converter application. In the AC/DC/AC converter the power losses are modelled, and different operating conditions are compared like different voltage levels in the DC-link. It is concluded dependent on operation conditions different devices will be preferable, but the high voltage devices have the highest losses even at a high operating voltage.

  16. Total AC losses in twisted and untwisted multifilamentary Bi-2223 superconducting tapes carrying AC transport current in AC longitudinal magnetic field

    NASA Astrophysics Data System (ADS)

    Amemiya, Naoyuki; Jin, Feng; Jiang, Zhenan; Shirai, Shunsuke; ten Haken, Bennie; Rabbers, Jan-Jaap; Ayai, Naoki; Hayashi, Kazuhiko

    2003-03-01

    In some electrical apparatuses, superconducting tapes are exposed to the longitudinal magnetic field. In this work, AC losses were measured in twisted and untwisted Bi-2223 tapes carrying AC transport current in the AC longitudinal magnetic field. In twisted tapes, the transport, magnetization and total losses depend on the relative direction of the longitudinal magnetic field to the direction of the transport current, while the field direction does not influence the AC loss characteristics in untwisted tapes. In the Z-twisted tapes, the total AC loss is larger in the longitudinal magnetic field that is anti-parallel to the transport current than in the longitudinal magnetic field of another direction. Numerical analysis shows that this field direction dependence of the total AC loss results from the change in the current distribution. In the longitudinal magnetic field that is anti-parallel to the transport current, the total AC loss in the Z-twisted tape is more than that in the untwisted tape. This dependence on the field direction is reversed in S-twisted tapes. It is to be noted that the twist increases the total AC loss in a longitudinal magnetic field of a certain direction, while it reduces the AC loss in the transverse magnetic field.

  17. Results of the 2008/2009 Knowledge and Opinions Surveys Conducted for the U.S. Department of Energy Hydrogen Program

    SciTech Connect

    Schmoyer, R. L.; Truett, Tykey; Cooper, Christy; Chew, Andrea

    2010-04-01

    This report presents results of a 2008/2009 survey of hydrogen and fuel cell awareness conducted for the U.S. Department of Energy (DOE). The 2008/2009 survey follows up on a similar DOE survey conducted in 2004, measuring levels of awareness and understanding of hydrogen and fuel cell technologies in four populations: (1) the general public, (2) students, (3) personnel in state and local governments, and (4) potential end users of hydrogen and fuel cell technologies in business and industry. The 2008/2009 survey includes these four groups and adds a fifth group, safety and code officials. The same survey methods were used for both surveys; the 2008/2009 survey report includes a comparison of 2004 and 2008/2009 findings. Information from these surveys will be used to enhance hydrogen and fuel cell education strategies.

  18. Structural characterization and AC conductivity of bis tetrapropylammonium hexachlorado-dicadmate, [N(C{sub 3}H{sub 7}){sub 4}]{sub 2}Cd{sub 2}Cl{sub 6}

    SciTech Connect

    Hannachi, N.; Guidara, K.; Bulou, A.; Hlel, F.

    2010-11-15

    Synthesis, crystal structure, vibrational study, {sup 13}C, {sup 111}Cd CP-MAS-NMR analysis and electrical properties of the compound [N(C{sub 3}H{sub 7}){sub 4}]{sub 2}Cd{sub 2}Cl{sub 6}, are reported. The latter crystallizes in the triclinic system (space group P1-bar, Z = 2) with the following unit cell dimensions: a = 9.530(1) A, b = 11.744(1) A, c = 17.433(1) A, {alpha} = 79.31(1){sup o}, {beta} = 84.00(1){sup o} and {gamma} = 80.32(1){sup o}. Besides, its structure was solved using 6445 independent reflections down to R = 0.037. The atomic arrangement can be described by alternating organic and inorganic layers parallel to the (11-bar 0) plan, made up of tetrapropylammonium groups and Cd{sub 2}Cl{sub 6} dimers, respectively. In crystal structure, the inorganic layer, built up by Cd{sub 2}Cl{sub 6} dimers, is connected to the organic ones through van der Waals interaction in order to build cation-anion-cation cohesion. Impedance spectroscopy study, reported in the sample, reveals that the conduction in the material is due to a hopping process. The temperature and frequency dependence of dielectric constants of the single crystal sample has been investigated to determine some related parameters to the dielectric relaxation.

  19. Cross-resistance and interactions between Bt toxins Cry1Ac and Cry2Ab against the cotton bollworm.

    PubMed

    Wei, Jizhen; Guo, Yuyuan; Liang, Gemei; Wu, Kongming; Zhang, Jie; Tabashnik, Bruce E; Li, Xianchun

    2015-01-14

    To delay evolution of pest resistance to transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt), the "pyramid" strategy uses plants that produce two or more toxins that kill the same pest. We conducted laboratory diet experiments with the cotton bollworm, Helicoverpa armigera, to evaluate cross-resistance and interactions between two toxins in pyramided Bt cotton (Cry1Ac and Cry2Ab). Selection with Cry1Ac for 125 generations produced 1000-fold resistance to Cry1Ac and 6.8-fold cross-resistance to Cry2Ab. Selection with Cry2Ab for 29 generations caused 5.6-fold resistance to Cry2Ab and 61-fold cross-resistance to Cry1Ac. Without exposure to Bt toxins, resistance to both toxins decreased. For each of the four resistant strains examined, 67 to 100% of the combinations of Cry1Ac and Cry2Ab tested yielded higher than expected mortality, reflecting synergism between these two toxins. Results showing minor cross-resistance to Cry2Ab caused by selection with Cry1Ac and synergism between these two toxins against resistant insects suggest that plants producing both toxins could prolong the efficacy of Bt cotton against this pest in China. Including toxins against which no cross-resistance occurs and integrating Bt cotton with other control tactics could also increase the sustainability of management strategies.

  20. Cross-resistance and interactions between Bt toxins Cry1Ac and Cry2Ab against the cotton bollworm

    PubMed Central

    Wei, Jizhen; Guo, Yuyuan; Liang, Gemei; Wu, Kongming; Zhang, Jie; Tabashnik, Bruce E.; Li, Xianchun

    2015-01-01

    To delay evolution of pest resistance to transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt), the "pyramid" strategy uses plants that produce two or more toxins that kill the same pest. We conducted laboratory diet experiments with the cotton bollworm, Helicoverpa armigera, to evaluate cross-resistance and interactions between two toxins in pyramided Bt cotton (Cry1Ac and Cry2Ab). Selection with Cry1Ac for 125 generations produced 1000-fold resistance to Cry1Ac and 6.8-fold cross-resistance to Cry2Ab. Selection with Cry2Ab for 29 generations caused 5.6-fold resistance to Cry2Ab and 61-fold cross-resistance to Cry1Ac. Without exposure to Bt toxins, resistance to both toxins decreased. For each of the four resistant strains examined, 67 to 100% of the combinations of Cry1Ac and Cry2Ab tested yielded higher than expected mortality, reflecting synergism between these two toxins. Results showing minor cross-resistance to Cry2Ab caused by selection with Cry1Ac and synergism between these two toxins against resistant insects suggest that plants producing both toxins could prolong the efficacy of Bt cotton against this pest in China. Including toxins against which no cross-resistance occurs and integrating Bt cotton with other control tactics could also increase the sustainability of management strategies. PMID:25586723

  1. High frequency conductivity of hot electrons in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Amekpewu, M.; Mensah, S. Y.; Musah, R.; Mensah, N. G.; Abukari, S. S.; Dompreh, K. A.

    2016-05-01

    High frequency conductivity of hot electrons in undoped single walled achiral Carbon Nanotubes (CNTs) under the influence of ac-dc driven fields was considered. We investigated semi-classically Boltzmann's transport equation with and without the presence of the hot electrons' source by deriving the current densities in CNTs. Plots of the normalized current density versus frequency of ac-field revealed an increase in both the minimum and maximum peaks of normalized current density at lower frequencies as a result of a strong injection of hot electrons. The applied ac-field plays a twofold role of suppressing the space-charge instability in CNTs and simultaneously pumping an energy for lower frequency generation and amplification of THz radiations. These have enormous promising applications in very different areas of science and technology.

  2. Theoretical and experimental study of meniscus behavior under AC electric field for Electrohydrodynamic (EHD) jetting

    NASA Astrophysics Data System (ADS)

    Tran, Si Bui Quang; Byun, Doyoung

    2009-11-01

    The electrohydrodynamic (EHD) spraying technique has been utilized in applications such as inkjet printing and mass spectrometry technologies. In this paper, the role of electrical potential signals in jetting and on the oscillation of the meniscus is evaluated. The jetting and meniscus oscillation behavior are experimentally investigated under ac voltage, ac voltage superimposed on dc voltage, and pulsed dc voltage. Furthermore, the analytical simulation about the oscillation of an anchored edge hemispherical meniscus located on a conductive flat plate under a uniform ac electric field is presented. The mutual interaction between the electric field and the hydrodynamics is iteratively solved. As a result, the simulation can calculate the meniscus shapes, contours of voltage outside the meniscus and the velocity profile of liquid inside the meniscus during the period of the oscillation according to the applied frequency. Based on the present theory, one can predict the oscillation mode with a certain applied frequency. The present theory can also be applied to investigate the oscillation of a free conductive drop in a uniform ac electric field.

  3. Results and harmonization guidelines from two large-scale international Elispot proficiency panels conducted by the Cancer Vaccine Consortium (CVC/SVI).

    PubMed

    Janetzki, Sylvia; Panageas, Katherine S; Ben-Porat, Leah; Boyer, Jean; Britten, Cedrik M; Clay, Timothy M; Kalos, Michael; Maecker, Holden T; Romero, Pedro; Yuan, Jianda; Kast, W Martin; Hoos, Axel

    2008-03-01

    The Cancer Vaccine Consortium of the Sabin Vaccine Institute (CVC/SVI) is conducting an ongoing large-scale immune monitoring harmonization program through its members and affiliated associations. This effort was brought to life as an external validation program by conducting an international Elispot proficiency panel with 36 laboratories in 2005, and was followed by a second panel with 29 participating laboratories in 2006 allowing for application of learnings from the first panel. Critical protocol choices, as well as standardization and validation practices among laboratories were assessed through detailed surveys. Although panel participants had to follow general guidelines in order to allow comparison of results, each laboratory was able to use its own protocols, materials and reagents. The second panel recorded an overall significantly improved performance, as measured by the ability to detect all predefined responses correctly. Protocol choices and laboratory practices, which can have a dramatic effect on the overall assay outcome, were identified and lead to the following recommendations: (A) Establish a laboratory SOP for Elispot testing procedures including (A1) a counting method for apoptotic cells for determining adequate cell dilution for plating, and (A2) overnight rest of cells prior to plating and incubation, (B) Use only pre-tested serum optimized for low background: high signal ratio, (C) Establish a laboratory SOP for plate reading including (C1) human auditing during the reading process and (C2) adequate adjustments for technical artifacts, and (D) Only allow trained personnel, which is certified per laboratory SOPs to conduct assays. Recommendations described under (A) were found to make a statistically significant difference in assay performance, while the remaining recommendations are based on practical experiences confirmed by the panel results, which could not be statistically tested. These results provide initial harmonization guidelines

  4. Results and harmonization guidelines from two large-scale international Elispot proficiency panels conducted by the Cancer Vaccine Consortium (CVC/SVI)

    PubMed Central

    Panageas, Katherine S.; Ben-Porat, Leah; Boyer, Jean; Britten, Cedrik M.; Clay, Timothy M.; Kalos, Michael; Maecker, Holden T.; Romero, Pedro; Yuan, Jianda; Martin Kast, W.; Hoos, Axel

    2007-01-01

    The Cancer Vaccine Consortium of the Sabin Vaccine Institute (CVC/SVI) is conducting an ongoing large-scale immune monitoring harmonization program through its members and affiliated associations. This effort was brought to life as an external validation program by conducting an international Elispot proficiency panel with 36 laboratories in 2005, and was followed by a second panel with 29 participating laboratories in 2006 allowing for application of learnings from the first panel. Critical protocol choices, as well as standardization and validation practices among laboratories were assessed through detailed surveys. Although panel participants had to follow general guidelines in order to allow comparison of results, each laboratory was able to use its own protocols, materials and reagents. The second panel recorded an overall significantly improved performance, as measured by the ability to detect all predefined responses correctly. Protocol choices and laboratory practices, which can have a dramatic effect on the overall assay outcome, were identified and lead to the following recommendations: (A) Establish a laboratory SOP for Elispot testing procedures including (A1) a counting method for apoptotic cells for determining adequate cell dilution for plating, and (A2) overnight rest of cells prior to plating and incubation, (B) Use only pre-tested serum optimized for low background: high signal ratio, (C) Establish a laboratory SOP for plate reading including (C1) human auditing during the reading process and (C2) adequate adjustments for technical artifacts, and (D) Only allow trained personnel, which is certified per laboratory SOPs to conduct assays. Recommendations described under (A) were found to make a statistically significant difference in assay performance, while the remaining recommendations are based on practical experiences confirmed by the panel results, which could not be statistically tested. These results provide initial harmonization guidelines

  5. Apple MdACS6 Regulates Ethylene Biosynthesis During Fruit Development Involving Ethylene-Responsive Factor.

    PubMed

    Li, Tong; Tan, Dongmei; Liu, Zhi; Jiang, Zhongyu; Wei, Yun; Zhang, Lichao; Li, Xinyue; Yuan, Hui; Wang, Aide

    2015-10-01

    Ethylene biosynthesis in plants involves different 1-aminocyclopropane-1-carboxylic acid synthase (ACS) genes. The regulation of each ACS gene during fruit development is unclear. Here, we characterized another apple (Malus×domestica) ACS gene, MdACS6. The transcript of MdACS6 was observed not only in fruits but also in other tissues. During fruit development, MdACS6 was initiated at a much earlier stage, whereas MdACS3a and MdACS1 began to be expressed at 35 d before harvest and immediateley after harvest, respectively. Moreover, the enzyme activity of MdACS6 was significantly lower than that of MdACS3a and MdACS1, accounting for the low ethylene biosynthesis in young fruits. Overexpression of MdACS6 (MdACS6-OE) by transient assay in apple showed enhanced ethylene production, and MdACS3a was induced in MdACS6-OE fruits but not in control fruits. In MdACS6 apple fruits silenced by the virus-induced gene silencing (VIGS) system (MdACS6-AN), neither ethylene production nor MdACS3a transcript was detectable. In order to explore the mechanism through which MdACS3a was induced in MdACS6-OE fruits, we investigated the expression of apple ethylene-responsive factor (ERF) genes. The results showed that the expression of MdERF2 was induced in MdACS6-OE fruits and inhibited in MdACS6-AN fruits. Yeast one-hybrid assay showed that MdERF2 protein could bind to the promoter of MdACS3a. Moreover, down-regulation of MdERF2 in apple flesh callus led to a decrease of MdACS3a expression, demonstrating the regulation of MdERF2 on MdACS3a. The mechanism through which MdACS6 regulates the action of MdACS3a was discussed.

  6. Optimal design of AC filter circuits in HVDC converter stations

    SciTech Connect

    Saied, M.M.; Khader, S.A.

    1995-12-31

    This paper investigates the reactive power as well as the harmonic conditions on both the valve and the AC-network sides of a HVDC converter station. The effect of the AC filter circuits is accurately modeled. The program is then augmented by adding an optimization routine. It can identify the optimal filter configuration, yielding the minimum current distortion factor at the AC network terminals for a prespecified fundamental reactive power to be provided by the filter. Several parameter studies were also conducted to illustrate the effect of accidental or intentional deletion of one of the filter branches.

  7. 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.

  8. 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.

  9. The ac and dc performance of polymeric insulating materials under accelerated aging in a fog chamber

    SciTech Connect

    Gorur, R.S. ); Cherney, E.A. ); Hackam, R. )

    1988-10-01

    The paper presents the results of the dc performance of polymeric insulating materials in a fog chamber. The materials evaluated in fog produced from low (250 ..mu..S/cm) and high (1000 ..mu..S/cm) conductivity water include cylindrical rod samples of high temperature vulcanized (HTV) silicone rubber and ethylene propylene diene monomer (EPDM) rubber containing various amounts of either alumina trihydrate (ATH) or silica fillers, or both. Comparison is made of material performance obtained with ac which was reported in an earlier study. In both low and high conductivity fog, the time to failure with ac and +dc was very similar, but a reduction by a factor of about four was observed in the time to failure with -dc. For both ac and dc, silicone rubber performed better than EPDM samples in low conductivity fog, while the order of performance was reversed in high conductivity fog. A theoretical model to determine the effect of dry band discharges on material is presented. Good agreement of the predicted behavior of materials with the experimental findings is shown.

  10. Experiments Conducted Aboard the International Space Station: The Pore Formation and Mobility Investigation (PFMI) and the In-Space Soldering Investigation (ISSI): A Current Study of Results

    NASA Technical Reports Server (NTRS)

    Grugel, R. N.; Luz, P.; Smith, G. A.; Spivey, R.; Jeter, L.; Gillies, D. C> ; Hua, F.; Anilkumar, A. V.

    2006-01-01

    Experiments in support of the Pore Formation and Mobility Investigation (PFMI) and the In-Space Soldering Investigation (ISSI) were conducted aboard the International Space Station (ISS) with the goal of promoting our fundamental understanding of melting dynamics , solidification phenomena, and defect generation during materials processing in a microgravity environment. Through the course of many experiments a number of observations, expected and unexpected, have been directly made. These include gradient-driven bubble migration, thermocapillary flow, and novel microstructural development. The experimental results are presented and found to be in good agreement with models pertinent to a microgravity environment. Based on the space station results, and noting the futility of duplicating them in Earth s unit-gravity environment, attention is drawn to the role ISS experimentslhardware can play to provide insight to potential materials processing techniques and/or repair scenarios that might arise during long duration space transport and/or on the lunar/Mars surface.

  11. 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.

  12. AC losses in a HTS coil carrying DC current in AC external magnetic field

    NASA Astrophysics Data System (ADS)

    Ogawa, J.; Zushi, Y.; Fukushima, M.; Tsukamoto, O.; Suzuki, E.; Hirakawa, M.; Kikukawa, K.

    2003-10-01

    We electrically measured AC losses in a Bi2223/Ag-sheathed pancake coil excited by a DC current in AC external magnetic field. Losses in the coil contain two kinds of loss components that are the magnetization losses and dynamic resistance losses. In the measurement, current leads to supply a current to the coil were specially arranged to suppress electromagnetic coupling between the coil current and the AC external magnetic field. A double pick-up coils method was used to suppress a large inductive voltage component contained in voltage signal for measuring the magnetization losses. It was observed that the magnetization losses were dependent on the coil current and that a peak of a curve of the loss factor vs. amplitude of the AC external magnetic field shifted to lower amplitude of the AC magnetic field as the coil current increased. This result suggests the full penetration magnetic field of the coil tape decreases as the coil current increases. The dynamic resistance losses were measured by measuring a DC voltage appearing between the coil terminals. It was observed that the DC voltage appearing in the coil subject to the AC external magnetic field was much larger than that in the coil subject to DC magnetic field.

  13. A highly potent agonist to protease-activated receptor-2 reveals apical activation of the airway epithelium resulting in Ca2+-regulated ion conductance

    PubMed Central

    Sherwood, Cara L.; Daines, Michael O.; Price, Theodore J.; Vagner, Josef

    2014-01-01

    The airway epithelium provides a barrier that separates inhaled air and its various particulates from the underlying tissues. It provides key physiological functions in both sensing the environment and initiating appropriate innate immune defenses to protect the lung. Protease-activated receptor-2 (PAR2) is expressed both apically and basolaterally throughout the airway epithelium. One consequence of basolateral PAR2 activation is the rapid, Ca2+-dependent ion flux that favors secretion in the normally absorptive airway epithelium. However, roles for apically expressed PAR2 activation have not been demonstrated, in part due to the lack of specific, high-potency PAR2 ligands. In the present study, we used the newly developed PAR2 ligand 2at-LIGRLO(PEG3-Pam)-NH2 in combination with well-differentiated, primary cultured airway epithelial cells from wild-type and PAR2−/− mice to examine the physiological role of PAR2 in the conducting airway after apical activation. Using digital imaging microscopy of intracellular Ca2+ concentration changes, we verified ligand potency on PAR2 in primary cultured airway cells. Examination of airway epithelial tissue in an Ussing chamber showed that apical activation of PAR2 by 2at-LIGRLO(PEG3-Pam)-NH2 resulted in a transient decrease in transepithelial resistance that was due to increased apical ion efflux. We determined pharmacologically that this increase in ion conductance was through Ca2+-activated Cl− and large-conductance K+ channels that were blocked with a Ca2+-activated Cl− channel inhibitor and clotrimazole, respectively. Stimulation of Cl− efflux via PAR2 activation at the airway epithelial surface can increase airway surface liquid that would aid in clearing the airway of noxious inhaled agents. PMID:25143347

  14. AC-electric field dependent electroformation of giant lipid vesicles.

    PubMed

    Politano, Timothy J; Froude, Victoria E; Jing, Benxin; Zhu, Yingxi

    2010-08-01

    Giant vesicles of larger than 5 microm, which have been of intense interest for their potential as drug delivery vehicles and as a model system for cell membranes, can be rapidly formed from a spin-coated lipid thin film under an electric field. In this work, we explore the AC-field dependent electroformation of giant lipid vesicles in aqueous media over a wide range of AC-frequency from 1 Hz to 1 MHz and peak-to-peak field strength from 0.212 V/mm to 40 V/mm between two parallel conducting electrode surfaces. By using fluorescence microscopy, we perform in-situ microscopic observations of the structural evolution of giant vesicles formed from spin-coated lipid films under varied uniform AC-electric fields. The real-time observation of bilayer bulging from the lipid film, vesicle growth and fusing further examine the critical role of AC-induced electroosmotic flow of surrounding fluids for giant vesicle formation. A rich AC-frequency and field strength phase diagram is obtained experimentally to predict the AC-electroformation of giant unilamellar vesicles (GUVs) of l-alpha-phosphatidylcholine, where a weak dependence of vesicle size on AC-frequency is observed at low AC-field voltages, showing decreased vesicle size with a narrowed size distribution with increased AC-frequency. Formation of vesicles was shown to be constrained by an upper field strength of 10 V/mm and an upper AC-frequency of 10 kHz. Within these parameters, giant lipid vesicles were formed predominantly unilamellar and prevalent across the entire electrode surfaces.

  15. Uncovering the Catalytic Direction of Chondroitin AC Exolyase

    PubMed Central

    Yin, Feng-Xin; Wang, Feng-Shan; Sheng, Ju-Zheng

    2016-01-01

    Glycosaminoglycans (GAGs) are polysaccharides that play vital functional roles in numerous biological processes, and compounds belonging to this class have been implicated in a wide variety of diseases. Chondroitin AC lyase (ChnAC) (EC 4.2.2.5) catalyzes the degradation of various GAGs, including chondroitin sulfate and hyaluronic acid, to give the corresponding disaccharides containing an Δ4-unsaturated uronic acid at their non-reducing terminus. ChnAC has been isolated from various bacteria and utilized as an enzymatic tool for study and evaluating the sequencing of GAGs. Despite its substrate specificity and the fact that its crystal structure has been determined to a high resolution, the direction in which ChnAC catalyzes the cleavage of oligosaccharides remain unclear. Herein, we have determined the structural cues of substrate depolymerization and the cleavage direction of ChnAC using model substrates and recombinant ChnAC protein. Several structurally defined oligosaccharides were synthesized using a chemoenzymatic approach and subsequently cleaved using ChnAC. The degradation products resulting from this process were determined by mass spectrometry. The results revealed that ChnAC cleaved the β1,4-glycosidic linkages between glucuronic acid and glucosamine units when these bonds were located on the reducing end of the oligosaccharide. In contrast, the presence of a GlcNAc-α-1,4-GlcA unit at the reducing end of the oligosaccharide prevented ChnAC from cleaving the GalNAc-β1,4-GlcA moiety located in the middle or at the non-reducing end of the chain. These interesting results therefore provide direct proof that ChnAC cleaves oligosaccharide substrates from their reducing end toward their non-reducing end. This conclusion will therefore enhance our collective understanding of the mode of action of ChnAC. PMID:26742844

  16. Comprehensive analysis of human cells motion under an irrotational AC electric field in an electro-microfluidic chip.

    PubMed

    Vaillier, Clarisse; Honegger, Thibault; Kermarrec, Frédérique; Gidrol, Xavier; Peyrade, David

    2014-01-01

    AC electrokinetics is a versatile tool for contact-less manipulation or characterization of cells and has been widely used for separation based on genotype translation to electrical phenotypes. Cells responses to an AC electric field result in a complex combination of electrokinetic phenomena, mainly dielectrophoresis and electrohydrodynamic forces. Human cells behaviors to AC electrokinetics remain unclear over a large frequency spectrum as illustrated by the self-rotation effect observed recently. We here report and analyze human cells behaviors in different conditions of medium conductivity, electric field frequency and magnitude. We also observe the self-rotation of human cells, in the absence of a rotational electric field. Based on an analytical competitive model of electrokinetic forces, we propose an explanation of the cell self-rotation. These experimental results, coupled with our model, lead to the exploitation of the cell behaviors to measure the intrinsic dielectric properties of JURKAT, HEK and PC3 human cell lines.

  17. Comprehensive Analysis of Human Cells Motion under an Irrotational AC Electric Field in an Electro-Microfluidic Chip

    PubMed Central

    Kermarrec, Frédérique; Gidrol, Xavier; Peyrade, David

    2014-01-01

    AC electrokinetics is a versatile tool for contact-less manipulation or characterization of cells and has been widely used for separation based on genotype translation to electrical phenotypes. Cells responses to an AC electric field result in a complex combination of electrokinetic phenomena, mainly dielectrophoresis and electrohydrodynamic forces. Human cells behaviors to AC electrokinetics remain unclear over a large frequency spectrum as illustrated by the self-rotation effect observed recently. We here report and analyze human cells behaviors in different conditions of medium conductivity, electric field frequency and magnitude. We also observe the self-rotation of human cells, in the absence of a rotational electric field. Based on an analytical competitive model of electrokinetic forces, we propose an explanation of the cell self-rotation. These experimental results, coupled with our model, lead to the exploitation of the cell behaviors to measure the intrinsic dielectric properties of JURKAT, HEK and PC3 human cell lines. PMID:24736275

  18. Dielectric properties and charge transfer in (TlInSe2)0.1(TlGaTe2)0.9 for the DC and AC current

    NASA Astrophysics Data System (ADS)

    Mustafaeva, S. N.; Asadov, M. M.; Dzhabbarov, A. I.

    2014-06-01

    The experimental results of studying the temperature and frequency dependences of dc and ac conductivity as well as the dispersion of dielectric coefficients of the grown single crystals of the (TlInSe2)0.1(TlGaTe2)0.9 solid solution are presented. The nature of dielectric losses and the hopping charge transfer mechanism have been established, and parameters of localized states, such as the density of states near the Fermi level and their spread, the average time and the hopping length of charge carriers, and the concentration of deep traps responsible for dc and ac conductivity, have been evaluated.

  19. Encapsulation of α-Particle–Emitting 225Ac3+ Ions Within Carbon Nanotubes

    PubMed Central

    Matson, Michael L.; Villa, Carlos H.; Ananta, Jeyarama S.; Law, Justin J.; Scheinberg, David A.; Wilson, Lon J.

    2016-01-01

    225Ac3+ is a generator of α-particle–emitting radionuclides with 4 net α-particle decays that can be used therapeutically. Targeting 225Ac3+ by use of ligands conjugated to traditional bifunctional chelates limits the amount of 225Ac3+ that can be delivered. Ultrashort, single-walled carbon nanotubes (US-tubes), previously demonstrated as sequestering agents of trivalent lanthanide ions and small molecules, also successfully incorporate 225Ac3+. Methods Aqueous loading of both 225Ac3+ ions and Gd3+ ions via bath sonication was used to construct 225Ac@gadonanotubes (225Ac@GNTs). The 225Ac@GNTs were subsequently challenged with heat, time, and human serum. Results US-tubes internally loaded with both 225Ac3+ ions and Gd3+ ions show 2 distinct populations of 225Ac3+ ions: one rapidly lost in human serum and one that remains bound to the US-tubes despite additional challenge with heat, time, and serum. The presence of the latter population depended on cosequestration of Gd3+ and 225Ac3+ ions. Conclusion US-tubes successfully sequester 225Ac3+ ions in the presence of Gd3+ ions and retain them after a human serum challenge, rendering 225Ac@GNTs candidates for radioimmunotherapy for delivery of 225Ac3+ ions at higher concentrations than is currently possible for traditional ligand carriers. PMID:25931476

  20. Cervical and ocular vestibular-evoked myogenic potentials in vestibular neuritis: comparison between air- and bone-conducted stimulation.

    PubMed

    Oh, Sun-Young; Kim, Ji-Soo; Yang, Tae-Ho; Shin, Byoung-Soo; Jeong, Seul-Ki

    2013-08-01

    To clarify the changes of cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials induced by air-conducted sound (ACS) and bone-conducted vibration (BCV) in patients with vestibular neuritis (VN), patients with VN (n = 30) and normal controls (n = 45) underwent recording of cVEMP and oVEMP in response to ACS (1,000 Hz, 5 ms, tone bursts) and BCV (500 Hz, short tone burst). Patients with VN showed a high proportion of oVEMP abnormalities in response to both ACS (80.0 %) and BCV at the forehead (Fz, 73.3 %) or the mastoid (76.7 %). In contrast, cVEMPs were mostly normal with both ACS and BCV in the patients. The dissociations in the abnormalities of cVEMP and oVEMP induced by ACS and BCV at the mastoids and at the forehead in patients with VN suggest that oVEMP reflects functions of the superior vestibular nerve and most likely the utricular function. The results of our study suggest that oVEMP induced by either ACS or BCV appears to depend on integrity of the superior vestibular nerve, possibly due to the utricular afferents travelling in it. In contrast, cVEMP elicited by either ACS or BCV may reflect function of the saccular afferents running in the inferior vestibular nerve.

  1. Electrical conduction through DNA molecule.

    PubMed

    Abdalla, S

    2011-09-01

    Several disorder parameters, inside the DNA molecule, lead to localization of charge carriers inside potential wells in the lowest unoccupied and highest occupied molecular orbits (LUMO and HOMO) which affects drastically the electrical conduction through the molecule, and demonstrates that the band carriers play an essential role in the conduction mechanism. So, a model is presented to shed light on the role of electrons of the LUMO in the electrical conduction through the DNA molecule. DC-, AC-conductivity and dielectric permittivity experimental data are well fitted with the presented model giving evidence that the free carriers in the LUMO and HOMO are responsible to make the DNA molecule conductor, insulator or semiconductor. The obtained results show that the localized charge carriers in the DNA molecule are characterized by four different types of relaxation phenomena which are thermally activated by corresponding four activation energies at 0.56 eV, 0.33 eV, 0.24 eV, and 0.05 eV respectively. Moreover, the calculations after the model, at room temperature, show that the time of the relaxation times of the current carriers are in the order of 5 × 10(-2)s, 1.74 × 10(-4)s, 5 × 10(-7)s, and 1.6 × 10(-10)s, respectively.

  2. ac-Field-induced fluid pumping in microsystems with asymmetric temperature gradients.

    PubMed

    Holtappels, Moritz; Stubbe, Marco; Gimsa, Jan

    2009-02-01

    We present two different designs of electrohydrodynamic micropumps for microfluidic systems. The micropumps have no movable parts, and their simple design allows for fabrication by microsystems technology. The pumps are operated by ac voltages from 1 to 60 V and were tested with aqueous solutions in the conductivity range of 1-112 mS m(-1). The pump effect is induced by an ac electric field across a fluid medium with an inhomogeneous temperature distribution. It is constant over a wide range of the ac field frequency with a conductivity-dependent drop-off at high frequencies. The temperature-dependent conductivity and permittivity distributions in the fluid induce space charges that interact with the electric field and induce fluid motion. The temperature distribution can be generated either by Joule heating in the medium or by external heating. We present experimental results obtained with two prototypes featuring Joule heating and external heating by a heating filament. Experimental and numerical results are compared with an analytical model.

  3. Experiment to determine electrical conductivity and equation of state data from Ohmically exploded tamped planar foils - preliminary diagnostic results and modeling

    NASA Astrophysics Data System (ADS)

    Ruden, E. L.; Amdahl, D. J.; Brown, D. J.; Grabowski, T. C.; Gregg, C. W.; Kostora, M. R.; Martinez, B. M.; Parker, J. V.; Camacho, J. F.; Coffey, S. K.; Poulsen, P.

    2009-11-01

    Diagnostic results from initial nondestructive (thick foil, low current) tests are presented for an experiment to simultaneously determine the electrical conductivity, pressure, density, specific energy, and temperature time histories of a planar metal foil tamped by a well characterized transparent material and exploded by a 36 μF, 50 kV rated capacitor bank discharge. Voltage differentials measure the foil's surface electric field, a B-dot probe measures surface current density, and a laser velocity interferometer (VISAR) measures dynamic foil thickness. From such and future filtered photodiode measurements, the desired properties will be inferred up to a few eV and within an order of magnitude of solid density. The purpose of the present phase of the experiment is to develop and validate diagnostic designs, data analysis techniques, and 2-D MHD simulations of the process using the MACH2 code.

  4. 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.

  5. Digital ac monitor

    DOEpatents

    Hart, G.W.; Kern, E.C. Jr.

    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. 24 figs.

  6. 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.

  7. The Results of Ground-based and In-flight Testing of Charge-dissipative and Conducting EKOM Thermal Control Paints

    NASA Astrophysics Data System (ADS)

    Kleiman, J. I.; Iskanderova, Z.; Issoupov, V.; Grigorevskiy, A. V.; Kiseleva, L. V.; Finckenor, M.; Naumov, S. F.; Sokolova, S. P.; Kurilenok, A. O.

    2009-01-01

    An international program on comparative evaluation of space durability of thermal control paints from a number of countries was initiated a few years ago at ITL with coatings from Russia, France and USA being studied. This paper describes the results of the study on space durability of three types of charge-dissipative and conductive Russian advanced polymer-based EKOM thermal control paints. Extensive ground-based testing in fast atomic oxygen (FAO) beam facilities was used to test the space durability of these paints and the enhancement of their atomic oxygen erosion resistance by a surface modification technology, Photosil™. All pristine EKOM paints were also tested in a direct materials exposure experiment on Russian module "Zvezda" onboard the International Space Station. Space durability and change of the major physical properties were evaluated after these experiments using a number of analytical techniques. Both, the ground-based testing and the flight experiments indicated signs of surface erosion with some changes of thermal optical properties. Therefore, the paints were also modified by a surface treatment technology, Photosil™, to increase their erosion resistance to atomic oxygen, tested in the same ground-based FAO facilities up to high FAO fluencies and compared with testing results of pristine materials. The comparison indicated that the surface-modified paints exhibit reduced mass loss, full stabilization and no surface morphology changes, thus indicating at full protection from the high FAO fluencies. It was demonstrated that the developed surface modification treatment could be applied successfully to charge dissipative and conductive paints, to enhance the low Earth orbit (LEO) environment resistance of external thermal control coatings in long-term space missions.

  8. Safety, Acceptability, and Feasibility of Early Infant Male Circumcision Conducted by Nurse-Midwives Using the AccuCirc Device: Results of a Field Study in Zimbabwe

    PubMed Central

    Mavhu, Webster; Larke, Natasha; Hatzold, Karin; Ncube, Getrude; Weiss, Helen A; Mangenah, Collin; Chonzi, Prosper; Mugurungi, Owen; Mufuka, Juliet; Samkange, Christopher A; Gwinji, Gerald; Cowan, Frances M; Ticklay, Ismail

    2016-01-01

    ABSTRACT Background: For prevention of HIV, early infant male circumcision (EIMC) needs to be scaled up in countries with high HIV prevalence. Routine EIMC will maintain the HIV prevention gains anticipated from current adult male circumcision initiatives. We present here the results of a field study of EIMC conducted in Zimbabwe. Methods: The study was observational and based on the World Health Organization (WHO) framework for clinical evaluation of male circumcision devices. We recruited parents of newborn male infants between August 2013 and July 2014 from 2 clinics. Nurse-midwives used the AccuCirc device to circumcise eligible infants. We followed participants for 14 days after EIMC. Outcome measures were EIMC safety, acceptability, and feasibility. Results: We enrolled 500 male infants in the field study (uptake 11%). The infants were circumcised between 6 and 60 days postpartum. The procedure took a median of 17 minutes (interquartile range of 5 to 18 minutes). Mothers’ knowledge of male circumcision was extensive. Of the 498 mothers who completed the study questionnaire, 91% knew that male circumcision decreases the risk of HIV acquisition, and 83% correctly stated that this prevention is partial. Asked about their community’s perception of EIMC, 40% felt that EIMC will likely be viewed positively in their community; 13% said negatively; and 47% said the perception could be both ways. We observed 7 moderate or severe adverse events (1.4%; 95% confidence interval, 0.4% to 2.4%). All resolved without lasting effects. Nearly all mothers (99%) reported great satisfaction with the outcome, would recommend EIMC to other parents, and would circumcise their next sons. Conclusion: This first field study in sub-Saharan Africa of the AccuCirc device for EIMC demonstrated that EIMC conducted by nurse-midwives with this device is safe, feasible, and acceptable to parents. PMID:27413083

  9. Parameters characterization and optimization of activated carbon (AC) cathodes for microbial fuel cell application.

    PubMed

    Santoro, Carlo; Artyushkova, Kateryna; Babanova, Sofia; Atanassov, Plamen; Ieropoulos, Ioannis; Grattieri, Matteo; Cristiani, Pierangela; Trasatti, Stefano; Li, Baikun; Schuler, Andrew J

    2014-07-01

    Activated carbon (AC) is employed as a cost-effective catalyst for cathodic oxygen reduction in microbial fuel cells (MFC). The fabrication protocols of AC-based cathodes are conducted at different applied pressures (175-3500 psi) and treatment temperatures (25-343°C). The effects of those parameters along with changes in the surface morphology and chemistry on the cathode performances are comprehensively examined. The cathodes are tested in a three-electrode setup and explored in single chamber membraneless MFCs (SCMFCs). The results show that the best performance of the AC-based cathode is achieved when a pressure of 1400 psi is applied followed by heat treatment of 150-200°C for 1h. The influence of the applied pressure and the temperature of the heat treatment on the electrodes and SCMFCs is demonstrated as the result of the variation in the transfer resistance, the surface morphology and surface chemistry of the AC-based cathodes tested.

  10. Comparative study of evaporation using DC and AC filament electron guns

    NASA Astrophysics Data System (ADS)

    Lahiri, Sutanwi; Sahu, G. K.; Baruah, S.; Jana, B.; Dixit, A. R.; Bhardwaj, R. L.; Das, R. C.; Kalra, R.; Kaushik, V.; Majumder, A.; Mohapatra, S.; Dikshit, B.; Mishra, K. K.; Bhatia, M. S.; Bapat, A. V.; Mago, V. K.; Thakur, K. B.; Das, A. K.; Gantayet, L. M.

    2012-11-01

    Electron beam assisted physical vapour deposition (EB-PVD) and purification of metal by repeated melting using electron guns is a well-established technique in industrial metallurgy. Strip electron gun is considered a cost effective alternative to multiple pencil guns for handling of large size substrates. In the electron guns, the thermionic emission of the electrons from a filament is achieved by using AC or DC filament heating. A study of their relative merits and demerits was conducted for the both types of electron guns. Due to finite length of the filament, the magnetic field generated around the filament by heating current drops down towards ends. The DC filament heating results in electron beam with a comet shape having high power density hot spot at one end with low power density tails. With AC filament heating, electron beam oscillates with the frequency as that of heating current. The study of vapour flux distribution using DC gun revealed that highly directional vapour evolution takes place from a smaller hot spot whereas with AC gun vapour evolution occurs from an oscillatory 2D-evaporating source. The vapour deposit on substrate indicated that evaporation using DC gun caused splashing and granular deposit due to volumetric melting and evaporation from the ingot. This is contrary to the AC filament heating wherein quiet evaporation was observed due to surface melting and evaporation. The experimental results are critically reviewed to decide the configuration of electron guns for large-scale evaporation.

  11. 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.

  12. Results for the hybrid laminar flow control experiment conducted in the NASA Langley 8-foot transonic pressure tunnel on a 7-foot chord model

    NASA Technical Reports Server (NTRS)

    Bobbitt, Percy J.; Ferris, James C.; Harvey, William D.; Goradia, Suresh H.

    1992-01-01

    A description is given of the development of, and results from, the hybrid laminar flow control (HLFC) experiment conducted in the NASA LaRC 8 ft Transonic Pressure Tunnel on a 7 ft chord, 23 deg swept model. The methods/codes used to obtain the contours of the HLFC model surface and to define the suction requirements are outlined followed by a discussion of the model construction, suction system, instrumentation, and some example results from the wind tunnel tests. Included in the latter are the effects of Mach number, suction level, and the extent of suction. An assessment is also given of the effect of the wind tunnel environment on the suction requirements. The data show that, at or near the design Mach number, large extents of laminar flow can be achieved with suction mass flows over the first 25 percent, or less, of the chord. Top surface drag coefficients with suction extending from the near leading edge to 20 percent of the chord were approximately 40 percent lower than those obtained with no suction. The results indicate that HLFC can be designed for transonic speeds with lift and drag coefficients approaching those of LFC designs but with much smaller extents and levels of suction.

  13. Results of the Round Robin on opening-load measurement conducted by ASTM Task Group E24.04.04 on Crack Closure Measurement and Analysis

    NASA Technical Reports Server (NTRS)

    Phillips, Edward P.

    1989-01-01

    An experimental Round Robin on the measurement of the opening load in fatigue crack growth tests was conducted on Crack Closure Measurement and Analysis. The Round Robin evaluated the current level of consistency of opening load measurements among laboratories and to identify causes for observed inconsistency. Eleven laboratories participated in the testing of compact and middle-crack specimens. Opening-load measurements were made for crack growth at two stress-intensity factor levels, three crack lengths, and following an overload. All opening-load measurements were based on the analysis of specimen compliance data. When all of the results reported (from all participants, all measurement methods, and all data analysis methods) for a given test condition were pooled, the range of opening loads was very large--typically spanning the lower half of the fatigue loading cycle. Part of the large scatter in the reported opening-load results was ascribed to consistent differences in results produced by the various methods used to measure specimen compliance and to evaluate the opening load from the compliance data. Another significant portion of the scatter was ascribed to lab-to-lab differences in producing the compliance data when using nominally the same method of measurement.

  14. Dielectric and AC conductivity studies of Nd substituted 0.8BaTiO3-0.2(Bi0.5(1-x)Nd0.5xK0.5)TiO3 lead free ceramics

    NASA Astrophysics Data System (ADS)

    Ramesh, M. N. V.; Ramesh, K. V.

    2016-05-01

    0.8BaTiO3 - 0.2(Bi0.5(1-x)Nd0.5xK0.5)TiO3 (0.01 ≤ x ≤ 0.06) lead free ceramic materials have been prepared by solid state reaction method and followed by high energy ball milling process. X-ray diffraction studies confirm the tetragonal structure of the materials at room temperature. Lattice parameters and density are decreasing with increase of Nd substitution. Microstructure studies were done by using Scanning electron microscope and it found that grain size is decreasing with increase of Nd substitution. Temperature and frequency dependent dielectric studies reveal relaxor behaviour of the materials. Dielectric constant, dielectric loss and Curie temperature are decreasing with Nd substitution. Maximum Curie temperature of 195°C was observed at 1MHz for x=0.01 Nd substituted sample. Degree of diffuseness was calculated from the modified Curie-Weiss law and it is increasing with Nd substitution. AC conductivity is increasing with increase of Nd substitution and observed maximum activation energy of 0.52 eV for x=0.02 Nd substituted sample.

  15. Heat conduction in conducting polyaniline nanofibers

    NASA Astrophysics Data System (ADS)

    Nath, Chandrani; Kumar, A.; Syu, K.-Z.; Kuo, Y.-K.

    2013-09-01

    Thermal conductivity and specific heat of conducting polyaniline nanofibers are measured to identify the nature of heat carrying modes combined with their inhomogeneous structure. The low temperature thermal conductivity results reveal crystalline nature while the high temperature data confirm the amorphous nature of the material suggesting heterogeneous model for conducting polyaniline. Extended acoustic phonons dominate the low temperature (<100 K) heat conduction, while localized optical phonons hopping, assisted by the extended acoustic modes, account for the high temperature (>100 K) heat conduction.

  16. Phylogenetic ecology of the freshwater Actinobacteria acI lineage.

    PubMed

    Newton, Ryan J; Jones, Stuart E; Helmus, Matthew R; McMahon, Katherine D

    2007-11-01

    The acI lineage of freshwater Actinobacteria is a cosmopolitan and often numerically dominant member of lake bacterial communities. We conducted a survey of acI 16S rRNA genes and 16S-23S rRNA internal transcribed spacer regions from 18 Wisconsin lakes and used standard nonphylogenetic and phylogenetic statistical approaches to investigate the factors that determine acI community composition at the local scale (within lakes) and at the regional scale (across lakes). Phylogenetic reconstruction of 434 acI 16S rRNA genes revealed a well-defined and highly resolved phylogeny. Eleven previously unrecognized monophyletic clades, each with > or =97.9% within-clade 16S rRNA gene sequence identity, were identified. Clade community similarity positively correlated with lake environmental similarity but not with geographic distance, implying that the lakes represent a single biotic region containing environmental filters for communities that have similar compositions. Phylogenetically disparate clades within the acI lineage were most abundant at the regional scale, and local communities were comprised of more closely related clades. Lake pH was a strong predictor of the community composition, but only when lakes with a pH below 6 were included in the data set. In the remaining lakes (pH above 6) biogeographic patterns in the landscape were instead a predictor of the observed acI community structure. The nonrandom distribution of the newly defined acI clades suggests potential ecophysiological differences between the clades, with acI clades AI, BII, and BIII preferring acidic lakes and acI clades AII, AVI, and BI preferring more alkaline lakes.

  17. Inter-lab testing of Hyalella azteca water and sediment methods: 4 Results from 10- to 42-d tests conducted with sediment substrates

    EPA Science Inventory

    Over the past four years, USEPA Duluth, USGS Columbia, the Illinois Natural History Survey, and Environment Canada have been conducting studies to refine the USEPA and ASTM International methods for conducting 10- to 42-d water or sediment toxicity exposures with the amphipod Hya...

  18. Inter-lab testing of Hyalella azteca water and sediment methods: 3 Results from 10- to 42-d tests conducted with the new water-only method

    EPA Science Inventory

    Over the past four years, USEPA-Duluth, USGS-Columbia, the Illinois Natural History Survey, and Environment Canada have been conducting studies to refine the USEPA and ASTM International methods for conducting 10- to 42-d water or sediment toxicity exposures with the amphipod Hya...

  19. AC power generation from microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

    2015-11-01

    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  20. A dry-cooled AC quantum voltmeter

    NASA Astrophysics Data System (ADS)

    Schubert, M.; Starkloff, M.; Peiselt, K.; Anders, S.; Knipper, R.; Lee, J.; Behr, R.; Palafox, L.; Böck, A. C.; Schaidhammer, L.; Fleischmann, P. M.; Meyer, H.-G.

    2016-10-01

    The paper describes a dry-cooled AC quantum voltmeter system operated up to kilohertz frequencies and 7 V rms. A 10 V programmable Josephson voltage standard (PJVS) array was installed on a pulse tube cooler (PTC) driven with a 4 kW air-cooled compressor. The operating margins at 70 GHz frequencies were investigated in detail and found to exceed 1 mA Shapiro step width. A key factor for the successful chip operation was the low on-chip power consumption of 65 mW in total. A thermal interface between PJVS chip and PTC cold stage was used to avoid a significant chip overheating. By installing the cryocooled PJVS array into an AC quantum voltmeter setup, several calibration measurements of dc standards and calibrator ac voltages up to 2 kHz frequencies were carried out to demonstrate the full functionality. The results are discussed and compared to systems with standard liquid helium cooling. For dc voltages, a direct comparison measurement between the dry-cooled AC quantum voltmeter and a liquid-helium based 10 V PJVS shows an agreement better than 1 part in 1010.

  1. 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.

  2. Layoff Handling Still Lags ACS Standards.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1981

    1981-01-01

    Reviews termination procedures of professional chemists and the compliance of these terminations to the American Chemical Society's (ACS's) Professional Employment Guidelines. Provides the ACS guidelines. (DS)

  3. Phase modulation mode of scanning ion conductance microscopy

    SciTech Connect

    Li, Peng; Zhang, Changlin; Liu, Lianqing E-mail: gli@engr.pitt.edu; Wang, Yuechao; Yang, Yang; Li, Guangyong E-mail: gli@engr.pitt.edu

    2014-08-04

    This Letter reports a phase modulation (PM) mode of scanning ion conductance microscopy. In this mode, an AC current is directly generated by an AC voltage between the electrodes. The portion of the AC current in phase with the AC voltage, which is the current through the resistance path, is modulated by the tip-sample distance. It can be used as the input of feedback control to drive the scanner in Z direction. The PM mode, taking the advantages of both DC mode and traditional AC mode, is less prone to electronic noise and DC drift but maintains high scanning speed. The effectiveness of the PM mode has been proven by experiments.

  4. DC and ac electrical properties of the chalcogenide semiconductor Se0.9In0.1

    NASA Astrophysics Data System (ADS)

    El-Hakim, S. A.; El-Wahab, F. A.; Mohamed, A. S.; Kotkata, M. F.

    2003-07-01

    Se0.9In0.1 samples were prepared from their highly pure constituents, by ice-water quenching from the melts. Structural characterization using XRD and DTA has revealed a stable phase consisting of some crystalline clusters embedded in a glassy matrix with a single glass transition (Tg) at a temperature 320 K, an onset exothermic crystallization peak at 361 K, and a melting endotherm with a melting point at 473 K. The dc (ohmic contact region) and ac (50 Hz-80 kHz) conductivities were measured under vacuum as a function of temperature (from T < Tg down to LN2) for massive samples, 0.3-0.6 mm thick. Results of the space-charge-limited current and the electrical characteristics of both dc and ac conduction are given and discussed in the light of the temperature dependence of the conduction mechanism.

  5. Results of the 2008/2009 Knowledge and Opinions Surveys Conducted for the U.S. Department of Energy Hydrogen Program

    SciTech Connect

    Schmoyer, Richard L; Truett, Lorena Faith; Cooper, Christy; Chew, Andrea

    2010-04-01

    The U.S. Department of Energy (DOE) Fuel Cell Technologies Program (FCT) conducts comprehensive efforts to enable the widespread commercialization of fuel cells in diverse sectors of the economy - with emphasis on applications that will most effectively strengthen our nation's energy security and improve our stewardship of the environment. Expanding the use of fuel cells requires a sustained education effort to lay the foundation for future commercial market introduction. The FCT education subprogram seeks to facilitate fuel cell demonstrations and support future commercialization by providing technically accurate and objective information to key target audiences both directly and indirectly involved in the use of fuel cells today. These key target audiences include a public that is familiar and comfortable with using a new fuel, state and local government officials who understand the near-term realities and long-term potential of the technology, an educated business and industry component, and trained safety and codes officials. With this in mind, the DOE FCT program established an education key activity to address the training and informational needs of target audiences that have a role in the near-term transition and the long-term development of a hydrogen economy. Whether or not changes can be attributed to the program, designing and maintaining an effective education program entails measuring baseline awareness and periodically measuring what has been learned. The purpose of this report is to document the data and results of statistical surveys undertaken in 2008 and 2009 to measure and establish changes in understanding and awareness about hydrogen and fuel cell technologies since a baseline survey was conducted in 2004. This report is essentially a data book, a digest of the survey data and an exposition of changes in knowledge of and opinions about hydrogen and fuel cell technology since 2004. Many conclusions can be made from the survey data. However, the

  6. Deep electrical conductivity structure of the Rio Grande Rift in Colorado and New Mexico: Early results from a two-year magnetotelluric study

    NASA Astrophysics Data System (ADS)

    Feucht, D. W.; Bedrosian, P.; Sheehan, A. F.

    2013-12-01

    A wideband and long-period magnetotelluric experiment is underway across the Rio Grande Rift in Colorado and New Mexico in order to provide constraints on the thermal and rheological state of the lithosphere beneath this region of intra-continental extension. Magnetotellurics is a passive source electromagnetic technique that at long periods has depth penetration into the deep crust and upper mantle. Important questions about continental rifting remain unresolved, including the role of magmatism, volatiles and inherited lithospheric structure in the initiation and development of rifting. Recent seismic imaging studies show thinned crust and low seismic wavespeeds in the crust and upper mantle beneath the Rio Grande Rift. New and ongoing geodetic work confirms the low strain-rate environment of the region yet shows surprisingly uniform deformation over an area far wider than the rift's physiographic expression. Electrical conductivity models from this experiment will provide information complementary to these studies and can be used to determine the relative contributions of thermal and compositional heterogeneity in the crust and upper mantle to processes of continental extension. Over the past two years, magnetotelluric data has been collected at ~100 site locations along three 450 km long east-west transects of the rift axis. These three profiles extend across the northern, central, and southern portions of the rift and include sites in the High Plains, Colorado Front Range, southern Rocky Mountains, San Juan Basin, Sangre de Cristo Mountains, and southern Basin and Range along the New Mexico/Mexico border. A comparison of results from these segments will be used to examine along-strike variation in the spatial extent of rifting and associated modification of the lithosphere. Data assessment shows high-quality signal to periods in excess of 10 000 s, which corresponds to upper-mantle depths in this region of high upper-crustal conductivity and low crustal

  7. Preliminary results of thermal conductivity and elastic wave velocity measurements of various rock samples collected from outcrops in hanging wall of the Alpine Fault

    NASA Astrophysics Data System (ADS)

    Lin, W.; Tadai, O.; Shigematsu, N.; Nishikawa, O.; Mori, H.; Townend, J.; Capova, L.; Saito, S.; Kinoshita, M.

    2015-12-01

    The Alpine Fault is a mature active fault zone likely to rupture in the near future and DFDP aims to measure physical and chemical conditions within the fault. DFDP-2B borehole was drilled into hanging wall of the Alpine Fault. Downhole temperature measurements carried out in DFDP-2B borehole showed that the geothermal gradient in the hanging wall of the fault is very high, likely reaching to 130-150 °C/km (Sutherland et al., 2015 AGU Fall Meeting). To explain this abnormal feature, the determination of thermal properties of all the rock types in the hanging wall of the Alpine Fault is essential. To measure thermal properties and elastic wave velocities, we collected six typical rock block samples from outcrops in Stony creek and Gaunt creek. These include ultramylonite, mylonite, muscovite schist, garnet amphibolite, protomylonite and schist, which are representative of the hanging wall of the Alpine Fault. Their wet bulk densities are 2.7 - 2.8 g/cm3, and porosities are 1.4 - 3.0%. We prepared a pair of 4 cm cube specimens of each rock type with one flat plane parallel to the foliation. First, we measured thermal conductivity by the transient plane heat source (hot disc) method in a bulk mode, i.e. to deal with the rock as an isotropic material. However, several samples have clearly visible foliation and are likely to be anisotropic. Thus, the data measured in bulk mode provided an average value of the rocks in the range of approximately 2.4 - 3.2 W/mK. The next step will be to measure thermal conductivity in an anisotropic mode. We also measured P wave velocity (Vp) using the same samples, but in two directions, i.e. parallel and perpendicular to the foliation, respectively. Our preliminary results suggested that Vp is anisotropic in all the six rocks. Generally, Vp parallel to foliation is higher than that in the perpendicular direction. Vp in the parallel direction ranged in 5.5 - 6.0 km/s, whereas in the perpendicular direction it was 4.4 - 5.5 km/s. We

  8. AC Magnetic Properties of Large Volume of Water — Susceptibility Measurement in Unshielded Environment

    NASA Astrophysics Data System (ADS)

    Tsukada, Keiji; Kiwa, Toshihiko; Masuda, Yuuki

    2006-10-01

    To investigate the effect of low-frequency magnetic-field exposure of a human body, the low-frequency AC magnetic property of a large volume of water was measured by low-frequency magnetic field exposure (from 50 Hz to 1.2 kHz). The results indicate that the AC magnetic property of water is due to diamagnetism in the low-frequency range. The phase between the main magnetic field and the generated magnetic field remained constant at about 180°. Results were not affected by conductivity or pH. Moreover, the magnetic-field strength from water showed a susceptibility frequency dependence proportional to the frequency above approximately 400 Hz. Because of the incremental effects of susceptibility, the magnetic field from water was measured using a conventional magnetic sensor (magnetic resistive; MR) in an unshielded environment.

  9. Infrared conductivity of cuprates using Yang-Rice-Zhang ansatz: Review of our recent investigations

    SciTech Connect

    Singh, Navinder; Sharma, Raman

    2015-05-15

    A review of our recent investigations related to the ac transport properties in the psedogapped state of cuprate high temperature superconductors is presented. For our theoretical calculations we use a phenomenological Green’s function proposed by Yang, Rice and Zhang (YRZ). This is based upon the renormalized mean-field theory of the Hubbard model and takes into account the strong electron-electron interaction present in Cuprates. The pseudogap is also taken into account through a proposed self energy. We have tested the form of the Green’s function by computing ac conductivity of cuprates and then compared with experimental results. We found agreement between theory and experiment in reproducing the doping evolution of ac conductivity but there is a problem with absolute magnitudes and their frequency dependence. This shows a partial success of the YRZ ansatz. The ways to rectify it are suggested and worked out.

  10. The Effects of Corona on Current Surges Induced on Conducting Lines by EMP (Electromagnetic Pulse): A Comparison of Experiment Data with Results of Analytic Corona Models

    DTIC Science & Technology

    1987-09-01

    that produced by a nuclear detonation above the earth’s atmosphere, was performed in March, 1986 at Kirtland Air Force Base near Albuquerque, New Mexico ...March, 1986, an EMP corona experiment was conducted at Kirtland Air Force Base, New Mexico . This work was funded in part by the DOE and by the Defense...through ORNL and by the Defense Nuclear Agency (DNA), was conducted at Kirtland Air Force Base in New Mexico . The data obtained in this measurement program

  11. 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

  12. Indicators: Conductivity

    EPA Pesticide Factsheets

    Conductivity is a measure of the ability of water to pass an electrical current. Because dissolved salts and other inorganic chemicals conduct electrical current, conductivity increases as salinity increases.

  13. Development and test of the ASAT Bipropellant Attitude Control System (ACS) engine

    NASA Astrophysics Data System (ADS)

    Hodge, K. F.; Allen, K. A.; Hemmings, B.

    1993-06-01

    The recent Kinetic Energy Anti-Satellite (KE ASAT) Bipropellant Attitude Control System (ACS) Engine testing demonstrated and characterized performance and operational durability. Within the ASAT mission, the bipropellant engines are used to despin the missile after shroud deployment and to provide attitude control of the Kill Vehicle (KV) during all phases of the KV free flight. These engines provide all attitude control thrust from booster separation until target intercept. The ASAT ACS engine is unique both in the amount of on-time that the engine sees during a tactical mission scenario and the high thermal loads which result from performing two diametrically opposed missions with a single thruster - long steady state burns and very short response time pulse mode operations. Two flightweight ASAT ACS Bipropellant engines were individually tested in a developmental test program. Testing was conducted at ambient conditions. Hot-fire testing consisted of steady-state, mission duty cycle (MDC), Chamber Pressure (Pc) excursion, mixture ratio excursion, and pulse performance. Testing was conducted by Rockwell's Rocketdyne Division at the Santa Susana Field Laboratory (SSFL), Systems Test Laboratory IV (STL IV), Cell 37A. Two additional engine tests are planned and will include altitude testing. This paper will summarize engine development, component development testing, valve orificing and cold flow calibration, and engine hot-fire testing approach and results.

  14. Correlation of free-response and receiver-operating-characteristic area-under-the-curve estimates: Results from independently conducted FROC/ROC studies in mammography

    SciTech Connect

    Zanca, Federica; Hillis, Stephen L.; Claus, Filip; Van Ongeval, Chantal; Celis, Valerie; Provoost, Veerle; Yoon, Hong-Jun; Bosmans, Hilde

    2012-10-15

    Purpose: From independently conducted free-response receiver operating characteristic (FROC) and receiver operating characteristic (ROC) experiments, to study fixed-reader associations between three estimators: the area under the alternative FROC (AFROC) curve computed from FROC data, the area under the ROC curve computed from FROC highest rating data, and the area under the ROC curve computed from confidence-of-disease ratings. Methods: Two hundred mammograms, 100 of which were abnormal, were processed by two image-processing algorithms and interpreted by four radiologists under the FROC paradigm. From the FROC data, inferred-ROC data were derived, using the highest rating assumption. Eighteen months afterwards, the images were interpreted by the same radiologists under the conventional ROC paradigm; conventional-ROC data (in contrast to inferred-ROC data) were obtained. FROC and ROC (inferred, conventional) data were analyzed using the nonparametric area-under-the-curve (AUC), (AFROC and ROC curve, respectively). Pearson correlation was used to quantify the degree of association between the modality-specific AUC indices and standard errors were computed using the bootstrap-after-bootstrap method. The magnitude of the correlations was assessed by comparison with computed Obuchowski-Rockette fixed reader correlations. Results: Average Pearson correlations (with 95% confidence intervals in square brackets) were: Corr(FROC, inferred ROC) = 0.76[0.64, 0.84] > Corr(inferred ROC, conventional ROC) = 0.40[0.18, 0.58] > Corr (FROC, conventional ROC) = 0.32[0.16, 0.46]. Conclusions: Correlation between FROC and inferred-ROC data AUC estimates was high. Correlation between inferred- and conventional-ROC AUC was similar to the correlation between two modalities for a single reader using one estimation method, suggesting that the highest rating assumption might be questionable.

  15. Psychiatrists’ awareness of adherence to antipsychotic medication in patients with schizophrenia: results from a survey conducted across Europe, the Middle East, and Africa

    PubMed Central

    Olivares, José Manuel; Alptekin, Köksal; Azorin, Jean-Michel; Cañas, Fernando; Dubois, Vincent; Emsley, Robin; Gorwood, Philip; Haddad, Peter M; Naber, Dieter; Papageorgiou, George; Roca, Miquel; Thomas, Pierre; Martinez, Guadalupe; Schreiner, Andreas

    2013-01-01

    Background Nonadherence is common among patients with schizophrenia, although the rates vary according to means of assessment and patient population. Failure to adhere to medication can have a major impact on the course of illness and treatment outcomes, including increasing the risk of relapse and rehospitalization. Understanding psychiatrists’ perception of the causes and consequences of nonadherence is crucial to addressing adherence problems effectively. Methods The Europe, the Middle East, and Africa (EMEA) Spanish Adherencia Terapéutica en la Esquizofrenia (ADHES) survey was conducted by questionnaire during January–March 2010 among psychiatrists treating patients with schizophrenia in 36 countries. The survey comprised 20 questions. In addition to recording the demographic details of the 4722 respondents (~12% response rate), it canvassed their preferred methods of assessing adherence, their perceptions of adherence rates, reasons for nonadherence, and strategies to improve adherence. Results Psychiatrists estimated that 53% of their patients with schizophrenia were partially/nonadherent during the previous month. They estimated only one-third of patients who deteriorated after stopping medication were able to attribute this to nonadherence. Psychiatrists assessed adherence most often by patient interview. Lack of insight was viewed as the most important cause of medication discontinuation, followed by patients feeling better and thinking their medication unnecessary, and experiencing undesirable side effects. Considerably fewer psychiatrists viewed insufficient efficacy, cognitive impairment, or drug/alcohol abuse as the most important reasons for their patients stopping medication. Conclusion Psychiatrists throughout EMEA recognize the impact of partial/nonadherence to medication, with patient enquiry being the most commonly used means of assessment. There remains a need for more proactive management of patients with schizophrenia, particularly in

  16. Correlation of free-response and receiver-operating-characteristic area-under-the-curve estimates: Results from independently conducted FROC/ROC studies in mammography

    PubMed Central

    Zanca, Federica; Hillis, Stephen L.; Claus, Filip; Van Ongeval, Chantal; Celis, Valerie; Provoost, Veerle; Yoon, Hong-Jun; Bosmans, Hilde

    2012-01-01

    Purpose: From independently conducted free-response receiver operating characteristic (FROC) and receiver operating characteristic (ROC) experiments, to study fixed-reader associations between three estimators: the area under the alternative FROC (AFROC) curve computed from FROC data, the area under the ROC curve computed from FROC highest rating data, and the area under the ROC curve computed from confidence-of-disease ratings. Methods: Two hundred mammograms, 100 of which were abnormal, were processed by two image-processing algorithms and interpreted by four radiologists under the FROC paradigm. From the FROC data, inferred-ROC data were derived, using the highest rating assumption. Eighteen months afterwards, the images were interpreted by the same radiologists under the conventional ROC paradigm; conventional-ROC data (in contrast to inferred-ROC data) were obtained. FROC and ROC (inferred, conventional) data were analyzed using the nonparametric area-under-the-curve (AUC), (AFROC and ROC curve, respectively). Pearson correlation was used to quantify the degree of association between the modality-specific AUC indices and standard errors were computed using the bootstrap-after-bootstrap method. The magnitude of the correlations was assessed by comparison with computed Obuchowski-Rockette fixed reader correlations. Results: Average Pearson correlations (with 95% confidence intervals in square brackets) were: Corr(FROC, inferred ROC) = 0.76[0.64, 0.84] > Corr(inferred ROC, conventional ROC) = 0.40[0.18, 0.58] > Corr (FROC, conventional ROC) = 0.32[0.16, 0.46]. Conclusions: Correlation between FROC and inferred-ROC data AUC estimates was high. Correlation between inferred- and conventional-ROC AUC was similar to the correlation between two modalities for a single reader using one estimation method, suggesting that the highest rating assumption might be questionable. PMID:23039631

  17. Optimization of the Inclusion of Alzheimer's Disease Patients in International Multicenter Randomized Trials: Results of a National Survey Conducted in Memory Research Centers in France

    PubMed Central

    Tchalla, A.E.; Adam, C.; Gayot, C.; Cowppli-Bony, P.; Preux, P.M.; Dantoine, T.

    2013-01-01

    Introduction Since 2002, with the creation of Centers of Memory Resources and Research (CMRR), considerable progress has been made in France regarding the administrative and institutional framework within which Alzheimer's disease (AD) is managed. In this study, we explore three approaches that can help optimize the inclusion of patients in clinical trials related to AD. They are as follows: to assess communication concerning clinical trials on AD in French CMRR, to analyze the internal organization of these centers concerning the dynamics of inclusion, and to evaluate screening tools used. Methods A national, descriptive, cross-sectional survey was conducted in all CMRR in France between May 1 and July 31, 2011, using a self-administered questionnaire. All investigators, subinvestigators and the relevant CMRR personnel were involved. Results A total of 75% of the CMRR participated, and about 30% of the physicians contacted responded positively to the survey. Only 50% reported having communicated with health care professionals at least once in the previous 3 months, and less than 50% had communicated occasionally with the general public. A total of 75% of those surveyed had a research group but only half of the groups were active, 50% of the physicians did not have a consultation time dedicated to study recruitment, and 75% of the respondents had a screening tool in their CMRR but over half of them were not satisfied with it. Conclusion This investigation provides a basis for improving the screening of patients by both internal organizational development and adaptation of tools already available. Improvement requires promoting regular communication that is appropriate and targeted to health care professionals, smaller memory centers, associations and the public, and therefore, familiarizing the whole population with clinical research on AD. PMID:24348503

  18. Results of Toxicity Identification Evaluations (TIE`S) conducted on the A-01 outfall and its contributory waste streams, July 1996--February 1997

    SciTech Connect

    Specht, W.L.

    1997-03-01

    Toxicity tests were conducted at nine locations during the summer of 1996. The results indicated that A-01B, A-01C, A-03, A-04, A-05 and A-01 were toxic to the test species, Ceriodaphnia dubia, while A-01A, A-06, and WE-01 were not toxic. Beginning in August 1996, Toxicity Identification Evaluations (TIE`s) were initiated on all toxic outfalls in order to identify the toxicants responsible for the observed toxicity. A complete TIE was performed on A-01 because it is the regulatory compliance point for all of the combined waste streams that were tested. Only the portions of a TIE that are related to metal and chlorine toxicity were performed on the remaining locations because existing data indicated that metals and chlorine were present in potentially toxic quantities at these locations, and there was no evidence that other toxicants would be expected to be present in toxic amounts. The results of the TIE`s indicate that metals are responsible for most of the toxicity at all of the outfalls that were toxic and that chlorine contributed to the toxicity at two of the outfalls. Specifically, the toxicity at A-01B, A-01C, and A-01 was due to copper; the toxicity at A-03 was due to primarily to copper, although zinc also contributed to the toxicity; the toxicity at A-04 was due primarily to copper, with residual chlorine and zinc contributing to the toxicity; and the toxicity at A-05 was due primarily to copper, with residual chlorine contributing to the toxicity. A-03 was the most toxic outfall, with 100% mortality occurring at concentrations as low as 12.5% effluent. A-03 was found to have concentrations of copper, lead, and zinc that exceeded EPA water quality criteria by approximately two orders of magnitude. The metal concentrations at A-01 and WE-01, which is located approximately 0.5 miles downstream from A-01 were similar. However, A-01 was toxic, while WE-01 was not.

  19. Electrical conductivity of activated carbon-metal oxide nanocomposites under compression: a comparison study.

    PubMed

    Barroso-Bogeat, A; Alexandre-Franco, M; Fernández-González, C; Macías-García, A; Gómez-Serrano, V

    2014-12-07

    From a granular commercial activated carbon (AC) and six metal oxide (Al2O3, Fe2O3, SnO2, TiO2, WO3 and ZnO) precursors, two series of AC-metal oxide nanocomposites were prepared by wet impregnation, oven-drying at 120 °C, and subsequent heat treatment at 200 or 850 °C in an inert atmosphere. Here, the electrical conductivity of the resulting products was studied under moderate compression. The influence of the applied pressure, sample volume, mechanical work, and density of the hybrid materials was thoroughly investigated. The DC electrical conductivity of the compressed samples was measured at room temperature by the four-probe method. Compaction assays suggest that the mechanical properties of the nanocomposites are largely determined by the carbon matrix. Both the decrease in volume and the increase in density were relatively small and only significant at pressures lower than 100 kPa for AC and most nanocomposites. In contrast, the bulk electrical conductivity of the hybrid materials was strongly influenced by the intrinsic conductivity, mean crystallite size, content and chemical nature of the supported phases, which ultimately depend on the metal oxide precursor and heat treatment temperature. The supported nanoparticles may be considered to act as electrical switches either hindering or favouring the effective electron transport between the AC cores of neighbouring composite particles in contact under compression. Conductivity values as a rule were lower for the nanocomposites than for the raw AC, all of them falling in the range of semiconductor materials. With the increase in heat treatment temperature, the trend is toward the improvement of conductivity due to the increase in the crystallite size and, in some cases, to the formation of metals in the elemental state and even metal carbides. The patterns of variation of the electrical conductivity with pressure and mechanical work were slightly similar, thus suggesting the predominance of the pressure

  20. Comparative performance evaluation of advanced AC and DC EV propulsion systems

    NASA Astrophysics Data System (ADS)

    MacDowall, R. D.; Crumley, R. L.

    Idaho National Engineering Laboratory (INEL) evaluates EV propulsion systems and components for the U.S. Department of Energy (DOE) Electric and Hybrid Vehicle (EHV) Program. In this study, experimental data were used to evaluate the relative performances of the benchmark Chrysler/GE ETV-1 DC and the Ford/GE First Generation Single-Shaft AC (ETX-I) propulsion systems. Tests were conducted on the INEL's chassis dynamometer using identical aerodynamic and rolling resistance road-load coefficients and vehicle test weights. The results allowed a direct comparison of selected efficiency and performance characteristics for the two propulsion system technologies. The ETX-I AC system exhibited slightly lower system efficiency during constant speed testing than the ETV-1 DC propulsion system.

  1. Science Teaching in New Brunswick Grades 7, 8 and 9: Results of a Teacher Survey Conducted in May, 1990. Research Report Number 3.

    ERIC Educational Resources Information Center

    McFadden, Charles P.

    A survey of grade 7, 8 and 9 science teachers was conducted as part of a research program to determine the consequences for teaching and learning of the recent introduction of the SciencePlus Program developed by the Atlantic Science Curriculum Project and the need for further curriculum and professional development. The survey explored some of…

  2. Science Teaching in Nova Scotia Grades 7, 8 and 9: Results of a Teacher Survey Conducted in May, 1990. Research Report Number 2.

    ERIC Educational Resources Information Center

    McFadden, Charles P.

    A survey of grade 7, 8 and 9 science teachers was conducted as part of a research program to determine the consequences for teaching and learning of the recent introduction of the SciencePlus program developed by the Atlantic Science Curriculum Project and the need for further curriculum and professional development. The survey explored some of…

  3. Why Conduct A Program Evaluation? Five Reasons why Evaluation can Help an Out-of-School Time Program. Research-to-Results Brief. Publication #2007-31

    ERIC Educational Resources Information Center

    Metz, Allison J. R.

    2007-01-01

    In this brief, a program evaluation is defined, address common concerns program managers and practitioners have regarding evaluation, and outline five major reasons why conducting a program evaluation can benefit an out-of-school time program. Program evaluation is a valuable tool for program managers who are seeking to strengthen the quality of…

  4. Dielectrophoretic particle-particle interaction under AC electrohydrodynamic flow conditions.

    PubMed

    Lee, Doh-Hyoung; Yu, Chengjie; Papazoglou, Elisabeth; Farouk, Bakhtier; Noh, Hongseok M

    2011-09-01

    We used the Maxwell stress tensor method to understand dielectrophoretic particle-particle interactions and applied the results to the interpretation of particle behaviors under alternating current (AC) electrohydrodynamic conditions such as AC electroosmosis (ACEO) and electrothermal flow (ETF). Distinct particle behaviors were observed under ACEO and ETF. Diverse particle-particle interactions observed in experiments such as particle clustering, particles keeping a certain distance from each other, chain and disc formation and their rotation, are explained based on the numerical simulation data. The improved understanding of particle behaviors in AC electrohydrodynamic flows presented here will enable researchers to design better particle manipulation strategies for lab-on-a-chip applications.

  5. Alternative promoters regulate transcription of the gene that encodes stem cell surface protein AC133.

    PubMed

    Shmelkov, Sergey V; Jun, Lin; St Clair, Ryan; McGarrigle, Deirdre; Derderian, Christopher A; Usenko, Jaroslav K; Costa, Carla; Zhang, Fan; Guo, Xinzheng; Rafii, Shahin

    2004-03-15

    AC133 is a member of a novel family of cell surface proteins with 5 transmembrane domains. The function of AC133 is unknown. Although AC133 mRNA is detected in different tissues, its expression in the hematopoietic system is restricted to CD34+ stem cells. AC133 is also expressed on stem cells of other tissues, including endothelial progenitor cells. However, despite the potential importance of AC133 to the field of stem cell biology, nothing is known about the transcriptional regulation of AC133 expression. In this report we showed that the human AC133 gene has at least 9 distinctive 5'-untranslated region (UTR) exons, resulting in the formation of at least 7 alternatively spliced 5'-UTR isoforms of AC133 mRNA, which are expressed in a tissue-dependent manner. We found that transcription of these AC133 isoforms is controlled by 5 alternative promoters, and we demonstrated their activity on AC133-expressing cell lines using a luciferase reporter system. We also showed that in vitro methylation of 2 of these AC133 promoters completely suppresses their activity, suggesting that methylation plays a role in their regulation. Identification of tissue-specific AC133 promoters may provide a novel method to isolate tissue-specific stem and progenitor cells.

  6. Self-consistent modeling of terahertz waveguide and cavity with frequency-dependent conductivity

    NASA Astrophysics Data System (ADS)

    Huang, Y. J.; Chu, K. R.; Thumm, M.

    2015-01-01

    The surface resistance of metals, and hence the Ohmic dissipation per unit area, scales with the square root of the frequency of an incident electromagnetic wave. As is well recognized, this can lead to excessive wall losses at terahertz (THz) frequencies. On the other hand, high-frequency oscillatory motion of conduction electrons tends to mitigate the collisional damping. As a result, the classical theory predicts that metals behave more like a transparent medium at frequencies above the ultraviolet. Such a behavior difference is inherent in the AC conductivity, a frequency-dependent complex quantity commonly used to treat electromagnetics of metals at optical frequencies. The THz region falls in the gap between microwave and optical frequencies. However, metals are still commonly modeled by the DC conductivity in currently active vacuum electronics research aimed at the development of high-power THz sources (notably the gyrotron), although a small reduction of the DC conductivity due to surface roughness is sometimes included. In this study, we present a self-consistent modeling of the gyrotron interaction structures (a metallic waveguide or cavity) with the AC conductivity. The resulting waveguide attenuation constants and cavity quality factors are compared with those of the DC-conductivity model. The reduction in Ohmic losses under the AC-conductivity model is shown to be increasingly significant as the frequency reaches deeper into the THz region. Such effects are of considerable importance to THz gyrotrons for which the minimization of Ohmic losses constitutes a major design consideration.

  7. A monitor for continuous measurement of temperature, pH, and conductance of wet precipitation: Preliminary results from the Adirondack Mountains, New York

    USGS Publications Warehouse

    Johnsson, P.A.; Reddy, M.M.

    1990-01-01

    This report describes a continuous wet-only precipitation monitor designed by the U.S. Geological Survey to record variations in rainfall temperature, pH, and specific conductance at 1-min intervals over the course of storms. Initial sampling in the Adirondack Mountains showed that rainfall acidity varied over the course of summer storms, with low initial pH values increasing as storm intensity increased.This report describes a continuous wet-only precipitation monitor designed by the U.S. Geological Survey to record variations in rainfall temperature, pH, and specific conductance at 1-min intervals over the course of storms. Initial sampling in the Adirondack Mountains showed that rainfall acidity varied over the course of summer storms, with low initial pH values increasing as storm intensity increased.

  8. Optimization of spin-torque switching using AC and DC pulses

    SciTech Connect

    Dunn, Tom; Kamenev, Alex

    2014-06-21

    We explore spin-torque induced magnetic reversal in magnetic tunnel junctions using combined AC and DC spin-current pulses. We calculate the optimal pulse times and current strengths for both AC and DC pulses as well as the optimal AC signal frequency, needed to minimize the Joule heat lost during the switching process. The results of this optimization are compared against numeric simulations. Finally, we show how this optimization leads to different dynamic regimes, where switching is optimized by either a purely AC or DC spin-current, or a combination AC/DC spin-current, depending on the anisotropy energies and the spin-current polarization.

  9. NONLINEAR DIAGNOSTICS USING AC DIPOLES.

    SciTech Connect

    PEGGS,S.

    1999-03-29

    There are three goals in the accurate nonlinear diagnosis of a storage ring. First, the beam must be moved to amplitudes many times the natural beam size. Second, strong and long lasting signals must be generated. Third, the measurement technique should be non-destructive. Conventionally, a single turn kick moves the beam to large amplitudes, and turn-by-turn data are recorded from multiple beam position monitors (BPMs) [1-6]. Unfortunately, tune spread across the beam causes the center of charge beam signal to ''decohere'' on a time scale often less than 100 turns. Filamentation also permanently destroys the beam emittance (in a hadron ring). Thus, the ''strong single turn kick'' technique successfully achieves only one out of the three goals. AC dipole techniques can achieve all three. Adiabatically excited AC dipoles slowly move the beam out to large amplitudes. The coherent signals then recorded last arbitrarily long. The beam maintains its original emittance if the AC dipoles are also turned off adiabatically, ready for further use. The AGS already uses an RF dipole to accelerate polarized proton beams through depolarizing resonances with minimal polarization loss [7]. Similar AC dipoles will be installed in the horizontal and vertical planes of both rings in RHIC [8]. The RHIC AC dipoles will also be used as spin flippers, and to measure linear optical functions [9].

  10. Channel model for AC electric arc

    NASA Astrophysics Data System (ADS)

    Larsen, H. L.

    1993-06-01

    This report contains the results from calculations of free-burning AC electric arcs in argon. In order to calculate the arc current and arc voltage, the external electric circuit must be taken into consideration. The external circuit is modeled by an equivalent circuit consisting of an ideal AC voltage source, a loss resistance, and an inductance. The qualitative behavior of the current-voltage characteristic is in agreement with observed characteristics, but experimental data are necessary in order to check whether the calculated power loss is reasonable. Non-symmetry was modeled by introducing different anode and cathode falls in the two half periods. An attempt at taking into account different cathode current densities in the two half periods, depending on whether the electrode or silicon melt is cathode, did not give satisfactory results. Thermionic emission was assumed in both half periods, but this may not be the right mechanism when the silicon melt is cathode. The time delay of the AC arc compared to the DC case is modeled by a time constant. It was shown that this preset time constant must be in agreement with the mean 'mechanical' relaxation time in the arc in order to fulfill the energy balance. By updating the time constant until this is achieved, the time constant is eliminated as a parameter that must be chosen a priori.

  11. Electrical Conductivity.

    ERIC Educational Resources Information Center

    Allen, Philip B.

    1979-01-01

    Examines Drude's classical (1900) theory of electrical conduction, details the objections to and successes of the 1900 theory, and investigates the Quantum (1928) theory of conduction, reviewing its successes and limitations. (BT)

  12. Exenatide: AC 2993, AC002993, AC2993A, exendin 4, LY2148568.

    PubMed

    2004-01-01

    Exenatide [AC002993, AC2993A, AC 2993, LY2148568, exendin 4], a glucagon-like peptide-1 (GLP-1) agonist, is a synthetic exendin 4 compound under development with Amylin Pharmaceuticals for the treatment of type 2 diabetes. Both exendin 4 and its analogue, exendin 3, are 39-amino acid peptides isolated from Heloderma horridum lizard venom that have different amino acids at positions 2 and 3, respectively. Exendins are able to stimulate insulin secretion in response to rising blood glucose levels, and modulate gastric emptying to slow the entry of ingested sugars into the bloodstream. Amylin Pharmaceuticals acquired exclusive patent rights for the two exendin compounds (exendin 3 and exendin 4) from the originator, Dr John Eng (Bronx, NY, US). On 20 September 2002, Amylin and Eli Lilly signed a collaborative agreement for the development and commercialisation of exenatide for type 2 diabetes. Under the terms of the agreement, Eli Lilly has paid Amylin a licensing fee of 80 million US dollars and bought Amylin's stock worth 30 million US dollars at 18.69 US dollars a share. After the initial payment, Eli Lilly will pay Amylin up to 85 US dollars million upon reaching certain milestones and also make an additional payment of up to 130 million US dollars upon global commercialisation of exenatide. Both companies will share the US development and commercialisation costs, while Eli Lilly will pick up up to 80% of development costs and all commercialisation costs outside the US. Amylin and Eli Lilly will equally share profit from sales in the US, while Eli Lilly will get 80% of the profit outside the US and Amylin will get the rest. This agreement has also enabled Amylin to train its sales force to co-promote Lilly's human growth hormone Humatrope. Alkermes will receive research and development funding and milestone payments, and also a combination of royalty payments and manufacturing fees based on product sales. Alkermes undertakes the responsibility for the development

  13. THE ACS NEARBY GALAXY SURVEY TREASURY

    SciTech Connect

    Dalcanton, Julianne J.; Williams, Benjamin F.; Rosema, Keith; Gogarten, Stephanie M.; Christensen, Charlotte; Gilbert, Karoline; Hodge, Paul; Seth, Anil C.; Dolphin, Andrew; Holtzman, Jon; Skillman, Evan D.; Weisz, Daniel; Cole, Andrew; Girardi, Leo; Karachentsev, Igor D.; Olsen, Knut; Freeman, Ken; Gallart, Carme; De Jong, Roelof S. E-mail: ben@astro.washington.edu E-mail: stephanie@astro.washington.edu E-mail: fabio@astro.washington.edu E-mail: aseth@cfa.harvard.edu

    2009-07-15

    The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D < 4 Mpc). The survey volume encompasses 69 galaxies in diverse environments, including close pairs, small and large groups, filaments, and truly isolated regions. The galaxies include a nearly complete range of morphological types spanning a factor of {approx}10{sup 4} in luminosity and star formation rate. The survey data consist of images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST), supplemented with archival data and new Wide Field Planetary Camera 2 (WFPC2) imaging taken after the failure of ACS. Survey images include wide field tilings covering the full radial extent of each galaxy, and single deep pointings in uncrowded regions of the most massive galaxies in the volume. The new wide field imaging in ANGST reaches median 50% completenesses of m {sub F475W} = 28.0 mag, m {sub F606W} = 27.3 mag, and m {sub F814W} = 27.3 mag, several magnitudes below the tip of the red giant branch (TRGB). The deep fields reach magnitudes sufficient to fully resolve the structure in the red clump. The resulting photometric catalogs are publicly accessible and contain over 34 million photometric measurements of >14 million stars. In this paper we present the details of the sample selection, imaging, data reduction, and the resulting photometric catalogs, along with an analysis of the photometric uncertainties (systematic and random), for both ACS and WFPC2 imaging. We also present uniformly derived relative distances measured from the apparent magnitude of the TRGB.

  14. The ACS Nearby Galaxy Survey Treasury

    NASA Astrophysics Data System (ADS)

    Dalcanton, Julianne J.; Williams, Benjamin F.; Seth, Anil C.; Dolphin, Andrew; Holtzman, Jon; Rosema, Keith; Skillman, Evan D.; Cole, Andrew; Girardi, Léo; Gogarten, Stephanie M.; Karachentsev, Igor D.; Olsen, Knut; Weisz, Daniel; Christensen, Charlotte; Freeman, Ken; Gilbert, Karoline; Gallart, Carme; Harris, Jason; Hodge, Paul; de Jong, Roelof S.; Karachentseva, Valentina; Mateo, Mario; Stetson, Peter B.; Tavarez, Maritza; Zaritsky, Dennis; Governato, Fabio; Quinn, Thomas

    2009-07-01

    The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D < 4 Mpc). The survey volume encompasses 69 galaxies in diverse environments, including close pairs, small and large groups, filaments, and truly isolated regions. The galaxies include a nearly complete range of morphological types spanning a factor of ~104 in luminosity and star formation rate. The survey data consist of images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST), supplemented with archival data and new Wide Field Planetary Camera 2 (WFPC2) imaging taken after the failure of ACS. Survey images include wide field tilings covering the full radial extent of each galaxy, and single deep pointings in uncrowded regions of the most massive galaxies in the volume. The new wide field imaging in ANGST reaches median 50% completenesses of m F475W = 28.0 mag, m F606W = 27.3 mag, and m F814W = 27.3 mag, several magnitudes below the tip of the red giant branch (TRGB). The deep fields reach magnitudes sufficient to fully resolve the structure in the red clump. The resulting photometric catalogs are publicly accessible and contain over 34 million photometric measurements of >14 million stars. In this paper we present the details of the sample selection, imaging, data reduction, and the resulting photometric catalogs, along with an analysis of the photometric uncertainties (systematic and random), for both ACS and WFPC2 imaging. We also present uniformly derived relative distances measured from the apparent magnitude of the TRGB.

  15. Results of borehole geophysical logging and hydraulic tests conducted in Area D supply wells, former US Naval Air Warfare Center, Warminster, Pennsylvania

    USGS Publications Warehouse

    Sloto, Ronald A.; Grazul, Kevin E.

    1998-01-01

    Borehole geophysical logging, aquifer tests, and aquifer-isolation (packer) tests were conducted in four supply wells at the former U.S. Naval Air Warfare Center (NAWC) in Warminster, PA to identify the depth and yield of water-bearing zones, occurrence of borehole flow, and effect of pumping on nearby wells. The study was conducted as part of an ongoing evaluation of ground-water contamination at the NAWC. Caliper, natural-gamma, single-point resistance, fluid resistivity, and fluid temperature logs and borehole television surveys were run in the supply wells, which range in depth from 242 to 560 ft (feet). Acoustic borehole televiewer and borehole deviation logs were run in two of the wells. The direction and rate of borehole-fluid movement under non-pumping conditions were measured with a high-resolution heatpulse flowmeter. The logs were used to locate water-bearing fractures, determine probable zones of vertical borehole-fluid movement, and determine the depth to set packers. An aquifer test was conducted in each well to determine open-hole specific capacity and the effect of pumping the open borehole on water levels in nearby wells. Specific capacities ranged from 0.21 to 1.7 (gal/min)/ft (gallons per minute per foot) of drawdown. Aquifer-isolation tests were conducted in each well to determine depth-discrete specific capacities and to determine the effect of pumping an individual fracture or fracture zone on water levels in nearby wells. Specific capacities of individual fractures and fracture zones ranged from 0 to 2.3 (gal/min)/ft. Most fractures identified as water-producing or water-receiving zones by borehole geophysical methods produced water when isolated and pumped. All hydrologically active fractures below 250 ft below land surface were identified as water-receiving zones and produced little water when isolated and pumped. In the two wells greater then 540 ft deep, downward borehole flow to the deep water-receiving fractures is caused by a large

  16. Differential Roles of AC2 and AC4 of Cassava Geminiviruses in Mediating Synergism and Suppression of Posttranscriptional Gene Silencing

    PubMed Central

    Vanitharani, Ramachandran; Chellappan, Padmanabhan; Pita, Justin S.; Fauquet, Claude M.

    2004-01-01

    Posttranscriptional gene silencing (PTGS) in plants is a natural defense mechanism against virus infection. In mixed infections, virus synergism is proposed to result from suppression of the host defense mechanism by the viruses. Synergistic severe mosaic disease caused by simultaneous infection with isolates of the Cameroon strain of African cassava mosaic virus (ACMV-[CM]) and East African cassava mosaic Cameroon virus (EACMCV) in cassava and tobacco is characterized by a dramatic increase in symptom severity and a severalfold increase in viral-DNA accumulation by both viruses compared to that in singly infected plants. Here, we report that synergism between ACMV-[CM] and EACMCV is a two-way process, as the presence of the DNA-A component of ACMV-[CM] or EACMCV in trans enhanced the accumulation of viral DNA of EACMCV and ACMV-[CM], respectively, in tobacco BY-2 protoplasts. Furthermore, transient expression of ACMV-[CM] AC4 driven by the Cauliflower mosaic virus 35S promoter (p35S-AC4) enhanced EACMCV DNA accumulation by ∼8-fold in protoplasts, while p35S-AC2 of EACMCV enhanced ACMV-[CM] DNA accumulation, also by ∼8-fold. An Agrobacterium-based leaf infiltration assay determined that ACMV-[CM] AC4 and EACMCV AC2, the putative synergistic genes, were able to suppress PTGS induced by green fluorescent protein (GFP) and eliminated the short interfering RNAs associated with PTGS, with a correlated increase in GFP mRNA accumulation. In addition, we have identified AC4 of Sri Lankan cassava mosaic virus and AC2 of Indian cassava mosaic virus as suppressors of PTGS, indicating that geminiviruses evolved differently in regard to interaction with the host. The specific and different roles played by these AC2 and AC4 proteins of cassava geminiviruses in regulating anti-PTGS activity and their relation to synergism are discussed. PMID:15308741

  17. 47 CFR 15.315 - Conducted limits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Conducted limits. 15.315 Section 15.315... Communications Service Devices § 15.315 Conducted limits. An unlicensed PCS device that is designed to be connected to the public utility (AC) power line must meet the limits specified in § 15.207....

  18. Conducting a thermal conductivity survey

    NASA Technical Reports Server (NTRS)

    Allen, P. B.

    1985-01-01

    A physically transparent approximate theory of phonon decay rates is presented starting from a pair potential model of the interatomic forces in an insulator or semiconductor. The theory applies in the classical regime and relates the 3-phonon decay rate to the third derivative of the pair potential. Phonon dispersion relations do not need to be calculated, as sum rules relate all the needed quantities directly to the pair potential. The Brillouin zone averaged phonon lifetime turns out to involve a dimensionless measure of the anharmonicity multiplied by an effective density of states for 3-phonon decay. Results are given for rare gas and alkali halide crystals. For rare gases, the results are in good agreement with more elaborate perturbation calculations. Comparison to experimental data on phonon linewidths and thermal conductivity are made.

  19. Degradation of Cry1Ac protein within transgenic Bacillus thuringiensis rice tissues under field and laboratory conditions.

    PubMed

    Li, Yunhe; Wu, Kongming; Zhang, Yongjun; Yuan, Guohui

    2007-10-01

    To clarify the environmental fate of the Cry1Ac protein from Bacillus thuringiensis subsp. kurstaki (Bt) contained in transgenic rice plant stubble after harvest, degradation was monitored under field conditions using an enzyme-linked immunosorbent assay. In stalks, Cry1Ac protein concentration decreased rapidly to 50% of the initial amount during the first month after harvest; subsequently, the degradation decreased gradually reaching 21.3% when the experiment was terminated after 7 mo. A similar degradation pattern of the Cry1Ac protein was observed in rice roots. However, when the temperature increased in April of the following spring, protein degradation resumed, and no protein could be detected by the end of the experiment. In addition, a laboratory experiment was conducted to study the persistence of Cry1Ac protein released from rice tissue in water and paddy soil. The protein released from leaves degraded rapidly in paddy soil under flooded conditions during the first 20 d and plateaued until the termination of this trial at 135 d, when 15.3% of the initial amount was still detectable. In water, the Cry1Ac protein degraded more slowly than in soil but never entered a relatively stable phase as in soil. The degradation rate of Cry1Ac protein was significantly faster in nonsterile water than in sterile water. These results indicate that the soil environment can increase the degradation of Bt protein contained in plant residues. Therefore, plowing a field immediately after harvest could be an effective method for decreasing the persistence of Bt protein in transgenic rice fields.

  20. 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.

  1. Study on the Crack Propagation Behavior of ×80 Pipeline Steel Under AC Application in High pH Solution

    NASA Astrophysics Data System (ADS)

    Zhu, M.; Ou, G. F.; Jin, H. Z.; Du, C. W.; Li, X. G.; Liu, Z. Y.

    2015-06-01

    The crack propagation behavior of pipeline steels with or without AC application was studied in high pH solution using the crack propagation experiment (cyclic load). The results show that there is a significant difference in the crack propagation behavior of steels with or without AC interference. The crack growth rate (CGR) of steel under superimposed AC is considerably greater than that without AC. AC could cause an obvious effect on the crack propagation behavior, and enhance the CGR. The crack propagation behavior of steel under AC application in high pH solution is analogous to that in near-neutral pH solution.

  2. Addressing the treatment gap and societal impact of epilepsy in Rwanda--Results of a survey conducted in 2005 and subsequent actions.

    PubMed

    Sebera, Fidèle; Munyandamutsa, Naasson; Teuwen, Dirk E; Ndiaye, Ibrahim Pierre; Diop, Amadou Gallo; Tofighy, Azita; Boon, Paul; Dedeken, Peter

    2015-05-01

    This study, supported by the Rwandan Ministry of Health and the World Health Organization, was conducted in 2005 to determine the prevalence of epilepsy and its sociocultural perception in Rwanda, as well as epilepsy-related knowledge and practices of health-care professionals (HCPs). A cross-sectional, nationally representative survey was conducted throughout Rwanda by trained investigators. Participants were recruited by random cluster sampling based on the organization of administrative units in the country. Overall, 1137 individuals (62% from rural areas) were interviewed. The prevalence of epilepsy was estimated to be 49 per 1000 people or 41 per 1000 for active epilepsy. Onset of epilepsy before the age of 2years was reported in 32% of the cases. Family history of epilepsy, head trauma, and premature delivery were reported in 53%, 50%, and 68% of the cases, respectively. Most (68%) patients did not receive any medical treatment for epilepsy; 21.5% had received some form of traditional treatment. According to responses from the general population, people with epilepsy should not be entitled to schooling (according to 66%), to work (according to 72%), to the use of public places (according to 69%), or to marriage (according to 66%). Furthermore, 50% believed that epilepsy was untreatable, and 40% thought that it was transmissible. Of the 29 HCPs interviewed, the majority knew the definition of epilepsy and status epilepticus, as well as basic treatment options and side effects. However, 90% believed that treatment was only necessary in the first week after a seizure. Living with epilepsy was associated heavily with stigma, and a significant treatment gap (68%) was identified. Following this study, numerous actions have been taken by the Rwandan government, the Rwandan League Against Epilepsy, and several nongovernmental organizations to increase awareness about epilepsy and to close the treatment gap. An overview of these activities is provided.

  3. Addressing the treatment gap and societal impact of epilepsy in Rwanda — Results of a survey conducted in 2005 and subsequent actions

    PubMed Central

    Sebera, Fidèle; Munyandamutsa, Naasson; Teuwen, Dirk E.; Ndiaye, Ibrahim Pierre; Diop, Amadou Gallo; Tofighy, Azita; Boon, Paul; Dedeken, Peter

    2015-01-01

    This study, supported by the Rwandan Ministry of Health and the World Health Organization, was conducted in 2005 to determine the prevalence of epilepsy and its sociocultural perception in Rwanda, as well as epilepsy-related knowledge and practices of health-care professionals (HCPs). A cross-sectional, nationally representative survey was conducted throughout Rwanda by trained investigators. Participants were recruited by random cluster sampling based on the organization of administrative units in the country. Overall, 1137 individuals (62% from rural areas) were interviewed. The prevalence of epilepsy was estimated to be 49 per 1000 people or 41 per 1000 for active epilepsy. Onset of epilepsy before the age of 2 years was reported in 32% of the cases. Family history of epilepsy, head trauma, and premature delivery were reported in 53%, 50%, and 68% of the cases, respectively. Most (68%) patients did not receive any medical treatment for epilepsy; 21.5% had received some form of traditional treatment. According to responses from the general population, people with epilepsy should not be entitled to schooling (according to 66%), to work (according to 72%), to the use of public places (according to 69%), or to marriage (according to 66%). Furthermore, 50% believed that epilepsy was untreatable, and 40% thought that it was transmissible. Of the 29 HCPs interviewed, the majority knew the definition of epilepsy and status epilepticus, as well as basic treatment options and side effects. However, 90% believed that treatment was only necessary in the first week after a seizure. Living with epilepsy was associated heavily with stigma, and a significant treatment gap (68%) was identified. Following this study, numerous actions have been taken by the Rwandan government, the Rwandan League Against Epilepsy, and several nongovernmental organizations to increase awareness about epilepsy and to close the treatment gap. An overview of these activities is provided. PMID:25936276

  4. Accelerator Production of 225Ac For Alpha-Immunotherapy

    NASA Astrophysics Data System (ADS)

    Weidner, J. W.; Nortier, F. M.; Bach, H. T.; John, K. D.; Couture, A.; Ullmann, J. L.; Fassbender, M. E.; Goff, G. S.; Taylor, W.; Valdez, F.; Wolfsberg, L. E.; Cisneros, M.; Dry, D.; Gallegos, M.; Gritzo, R.; Bitteker, L. J.; Wender, S.; Baty, R. S.

    2011-06-01

    225Ac has tremendous potential for the treatment of metastatic cancer due to the four alpha-particles emitted during its decay to stable 209Bi. Additionally, it is one of the few alpha-emitters being considered for clinical trials. The anticipated 225Ac demand for these trials is expected to far exceed the annual worldwide supply of approximately 1,000 mCi/yr. Consequently, the DOE Office of Science has funded investigations into accelerator-based production of 225Ac. Existing 232Th(p,x)225Ac cross section data indicate that up to 480 mCi/day of 225Ac could be created by bombarding a thick target of natural thorium with 100 MeV protons at the Los Alamos Isotope Production Facility. To verify these predictions, experiments are underway at the Los Alamos Neutron Science Center to measure the 232Th(p,x)225Ac production cross sections for protons in the energy range 40-200 MeV, and at 800 MeV. For 800 MeV protons, preliminary results indicate that the 225Ac production cross section is 12.4±0.6 mb and the 225Ra production cross section is 3.2±0.2 mb. Moreover, preliminary results suggest that the 227Ac production cross section is 16±1 mb. Experiments to measure these same cross sections at proton energies below 200 MeV are planned for the last half of calendar year 2010.

  5. Accelerator Production of {sup 225}Ac For Alpha-Immunotherapy

    SciTech Connect

    Weidner, J. W.; Nortier, F. M.; Bach, H. T.; John, K. D.; Couture, A.; Ullmann, J. L.; Fassbender, M. E.; Goff, G. S.; Taylor, W.; Valdez, F.; Wolfsberg, L. E.; Cisneros, M.; Dry, D.; Gallegos, M.; Gritzo, R.; Bitteker, L. J.; Wender, S.; Baty, R. S.

    2011-06-01

    {sup 225}Ac has tremendous potential for the treatment of metastatic cancer due to the four alpha-particles emitted during its decay to stable {sup 209}Bi. Additionally, it is one of the few alpha-emitters being considered for clinical trials. The anticipated {sup 225}Ac demand for these trials is expected to far exceed the annual worldwide supply of approximately 1,000 mCi/yr. Consequently, the DOE Office of Science has funded investigations into accelerator-based production of {sup 225}Ac. Existing {sup 232}Th(p,x){sup 225}Ac cross section data indicate that up to 480 mCi/day of {sup 225}Ac could be created by bombarding a thick target of natural thorium with 100 MeV protons at the Los Alamos Isotope Production Facility. To verify these predictions, experiments are underway at the Los Alamos Neutron Science Center to measure the {sup 232}Th(p,x){sup 225}Ac production cross sections for protons in the energy range 40-200 MeV, and at 800 MeV. For 800 MeV protons, preliminary results indicate that the {sup 225}Ac production cross section is 12.4{+-}0.6 mb and the {sup 225}Ra production cross section is 3.2{+-}0.2 mb. Moreover, preliminary results suggest that the {sup 227}Ac production cross section is 16{+-}1 mb. Experiments to measure these same cross sections at proton energies below 200 MeV are planned for the last half of calendar year 2010.

  6. Prompt and Delayed Spectroscopy of Ac isotopes around N = 126

    NASA Astrophysics Data System (ADS)

    Hota, S. S.; Lane, G. J.; Reed, M. W.; Mitchell, A. J.; Stuchbery, A. E.; Kibedi, T.; Akber, A. A.; Eriksen, T. E.; Gerathy, M. S.; Palalani, N.; Palazzo, T. R.

    2015-10-01

    Nuclei above Z = 82 and around N = 126 are well described by the spherical shell model, with the attractive proton-neutron residual interactions and particle-octupole vibration coupling resulting in energy-favored, isomeric states occurring along the yrast line. Nuclei up to Z = 88 are mostly well known, but information on Ac (Z = 89) isotopes is limited. We report on high-spin, gamma-ray spectroscopy measurements of 214 , 215 , 216 , 217Ac performed at the Australian National University using the CAESAR array and fusion-evaporation reactions between 12C and 14,15N beams delivered by the 14UD accelerator incident on 204Pb and 209Bi targets. States up to 29/2+ isomers were known previously in 215,217Ac, while only one gamma-ray has been assigned to each of 214,216Ac. New level schemes have now been constructed for 214,216Ac and those for 215,217Ac have been significantly extended. The results will be presented in detail together with semi-empirical shell model calculations that support the proposed level schemes.

  7. Electrical conductivity of polyazomethine/fullerene C60 nanocomposites

    NASA Astrophysics Data System (ADS)

    Bronnikov, Sergei; Podshivalov, Aleksandr; Kostromin, Sergei; Asandulesa, Mihai; Cozan, Vasile

    2017-02-01

    We prepared the polyazomethine/fullerene C60 nanocomposites varying in C60 loading. With a broadband dielectric relaxation spectrometer, we measured their electrical conductivity σm being a sum of dc conductivity σdc and ac conductivity σac. A small C60 content (0.25 and 0.5 wt.%) was shown to decrease σdc, whereas a larger amount of C60 (2.5 wt.%) was found to increase σdc of the nanocomposite. The temperature dependences of σac were described with the Arrhenius equation, while the frequency dependences of σac were characterized with a power function. The correlated barrier hopping was accepted as the most suitable mechanism to explain the σac behavior of the nanocomposites.

  8. ACS from development to operations

    NASA Astrophysics Data System (ADS)

    Caproni, Alessandro; Colomer, Pau; Jeram, Bogdan; Sommer, Heiko; Chiozzi, Gianluca; Mañas, Miguel M.

    2016-08-01

    The ALMA Common Software (ACS), provides the infrastructure of the distributed software system of ALMA and other projects. ACS, built on top of CORBA and Data Distribution Service (DDS) middleware, is based on a Component- Container paradigm and hides the complexity of the middleware allowing the developer to focus on domain specific issues. The transition of the ALMA observatory from construction to operations brings with it that ACS effort focuses primarily on scalability, stability and robustness rather than on new features. The transition came together with a shorter release cycle and a more extensive testing. For scalability, the most problematic area has been the CORBA notification service, used to implement the publisher subscriber pattern because of the asynchronous nature of the paradigm: a lot of effort has been spent to improve its stability and recovery from run time errors. The original bulk data mechanism, implemented using the CORBA Audio/Video Streaming Service, showed its limitations and has been replaced with a more performant and scalable DDS implementation. Operational needs showed soon the difference between releases cycles for Online software (i.e. used during observations) and Offline software, which requires much more frequent releases. This paper attempts to describe the impact the transition from construction to operations had on ACS, the solution adopted so far and a look into future evolution.

  9. Simple Equipment for Imaging AC.

    ERIC Educational Resources Information Center

    Kamata, Masahiro; Anayama, Takayuki

    2003-01-01

    Presents an effective way to demonstrate the difference between direct current and alternating current using red and green LEDs. Describes how to make a tool that shows how an AC voltage changes with time using the afterimage effect of the LEDs. (Author/NB)

  10. Determinants of the frequency of online health information seeking: results of a web-based survey conducted in France in 2007.

    PubMed

    Renahy, Emilie; Parizot, Isabelle; Chauvin, Pierre

    2010-01-01

    In the general population, social disparities in Internet practices have been less described than disparities in health information access. Aim is to determine whether there are differences in the frequency of Internet use for health information among health seekers. We conducted an Internet-based survey from November 2006 to March 2007. We considered the 3720 residents of France who had searched for health information during the previous 12 months. This study reveals different uses of the Internet for health information seeking (HIS) between men and women and between the general population and people who work in the health sector. Health status, taking care of somebody who is sick, and active Internet use were associated with higher frequencies of online HIS to varying degrees. The effects of age and level of education were not clear or were not significant. Greater health concerns and some issues in the physician-patient relationship were associated with higher frequencies of Internet use for HIS in the general population. Considering that this increasing use of online tools for HIS is consistent with current public health policies that promote the development of the 'informed patient', one should remain cautious about these social disparities in online HIS practices.

  11. AC impedance analysis of polypyrrole thin films

    NASA Technical Reports Server (NTRS)

    Penner, Reginald M.; Martin, Charles R.

    1987-01-01

    The AC impedance spectra of thin polypyrrole films were obtained at open circuit potentials from -0.4 to 0.4 V vs SCE. Two limiting cases are discussed for which simplified equivalent circuits are applicable. At very positive potentials, the predominantly nonfaradaic AC impedance of polypyrrole is very similar to that observed previously for finite porous metallic films. Modeling of the data with the appropriate equivalent circuit permits effective pore diameter and pore number densities of the oxidized film to be estimated. At potentials from -0.4 to -0.3 V, the polypyrrole film is essentially nonelectronically conductive and diffusion of polymer oxidized sites with their associated counterions can be assumed to be linear from the film/substrate electrode interface. The equivalent circuit for the polypyrrole film at these potentials is that previously described for metal oxide, lithium intercalation thin films. Using this model, counterion diffusion coefficients are determined for both semi-infinite and finite diffusion domains. In addition, the limiting low frequency resistance and capacitance of the polypyrrole thin fims was determined and compared to that obtained previously for thicker films of the polymer. The origin of the observed potential dependence of these low frequency circuit components is discussed.

  12. The mechanical and EM simulations of the CryoAC for the ATHENA X-IFU

    NASA Astrophysics Data System (ADS)

    Corsini, D.; Biasotti, M.; Gatti, F.; De Gerone, M.; Rossi, C.; Piro, L.; Macculi, C.

    2016-07-01

    The design phase of the CryoAC DM for the ATHENA X-IFU has concerned numerical simulations to exploit different fabrication possibilities. The mechanical simulations have accounted for the peculiar detector structure: 4 silicon chips asymmetrically suspended by means of 4 microbridges each. A preliminary study was performed to analyze the response to acceleration spectra in the frequency domain, shocks and time domain random displacement, prior to a real vibration test campaign. EM simulations to spot unwanted magnetic fields have been conducted as well. In this work we will show the latest advance in the design of the new detectors, showing the main results coming from various simulations.

  13. On the possibility of reduction of Ac{sup 3+} to Ac{sup 2+} in Aqueous-ethanolic solutions of bivalent samarium

    SciTech Connect

    Mikheev, N.B.; Veleshko, I.E.; Kamenskaya, A.N.

    1995-07-01

    In view of contradictory data on the existence of Ac{sup 2+} in aqueous solutions, the possibility of actinium reduction was examined in aqueous-ethanolic solutions in which bivalent f-elements are more stable than in aqueous media. In the presence of bivalent samarium (E{sub Sm}{sup 0}3+/Sm 2+=-1.5 V) Ac(III) is not reduced to Ac(II). These results disagree with the previously published data on the radiopolarographic generation of Ac(II) in aqueous solutions.

  14. Sequential control by speed drive for ac motor

    NASA Astrophysics Data System (ADS)

    Barsoum, Nader

    2012-11-01

    The speed drive for ac motor is widely used in the industrial field to allow direct control for the speed and torque without any feedback from the motor shaft. By using the ABB ACS800 speed drive unit, the speed and torque can be controlled using sequential control method. Sequential control is one of the application control method provided in the ABB ACS800 Drive, where a set of events or action performed in a particular order one after the other to control the speed and torque of the ac motor. It was claimed that sequential control method is using the preset seven constant speeds being provided in ABB ACS800 drive to control the speed and torque in a continuous and sequential manner. The characteristics and features of controlling the speed and torque using sequential control method can be investigated by observing the graphs and curves plotted which are obtained from the practical result. Sequential control can run either in the Direct Torque Control (DTC) or Scalar motor control mode. By using sequential control method, the ABB ACS800 drive can be programmed to run the motor automatically according to the time setting of the seven preset constant speeds. Besides, the intention of this project is to generate a new form of the experimental set up.

  15. Microwave conductance of aligned multiwall carbon nanotube textile sheets

    NASA Astrophysics Data System (ADS)

    Brown, Brian L.; Bykova, Julia S.; Howard, Austin R.; Zakhidov, Anvar A.; Shaner, Eric A.; Lee, Mark

    2014-12-01

    Multiwall carbon nanotube (MWNT) sheets are a class of nanomaterial-based multifunctional textile with potentially useful microwave properties. To understand better the microwave electrodynamics, complex AC conductance measurements from 0.01 to 50 GHz were made on sheets of highly aligned MWNTs with the alignment texture both parallel and perpendicular to the microwave electric field polarization. In both orientations, the AC conductance is modeled to first order by a parallel frequency-independent conductance and capacitance with no inductive contribution. This is consistent with low-frequency diffusive Drude AC conduction up to 50 GHz, in contrast to the "universal disorder" AC conduction reported in many types of single-wall nanotube materials.

  16. Optical Properties of AC60 Materials

    NASA Astrophysics Data System (ADS)

    Martin, Michael C.

    1996-03-01

    The alkali intercalated fullerene system A_1C_60 (A=K, Rb, or Cs) undergoes a number of structural and electronic phase transitions. At elevated temperatures the structure is fcc, but when cooled below ~ 100 ^circC the structure becomes dependent on the sample's thermal treatment. Infrared and Raman spectroscopic investigations into the various resultant phases will be presented.^1,2 Upon slow cooling, the C_60 molecules form linear conducting polymers^3 which break the icosahedral symmetry of the pure fullerene and thus activate many previously silent vibrational modes. This phase is unexpectedly found to be stable in air.^4 At much lower temperatures (30-60K) a magnetic transition has been observed; we will present IR data obtained in this thermal region showing indications of a gap-like feature. If the samples are cooled very rapidly from high temperatures, an insulating phase is formed where even more symmetry breaking occurs. We argue that a dimerization of C_60, Rb_2(C_60)_2, is the likely structure in accord with the vibrational spectra,^2 and recent x-ray results. Both lower-symmetry phases of AC_60 can also be used to help identify the IR- and Raman-silent modes of unperturbed C_60. Work done at the State University of New York at Stony Brook in collaboration with Daniel Koller, Peter W. Stephens, Laszlo Mihaly (State University of New York at Stony Brook), C. Kendziora and A. Rosenberg (Naval Research Laboratory). Supported by NSF Grant DMR9202528. ^1Michael C. Martin, Daniel Koller, Xiaoqun Du, Peter W. Stephens and Laszlo Mihaly, Phys. Rev. B 49, 10 818 (1994). ^2Michael C. Martin, Daniel Koller, A. Rosenberg, C. Kendziora, and L. Mihaly, Phys. Rev. B 51, 3210 (1995). ^3P.W. Stephens, G. Bortel, G. Faigel, M. Tegze, A. Jánossy, S. Pekker, G. Oszlányi and L. Forro, Nature (London) 370, 636 (1994). ^4Daniel Koller, Michael C. Martin, Peter W. Stephens, Laszlo Mihaly, Sandor Pekker, Andras Jánossy, Olivier Chauvet and Laszlo Forro, Appl. Phys. Lett. 66

  17. New perspectives on the dynamics of AC and DC plasma arcs exposed to cross-fields

    NASA Astrophysics Data System (ADS)

    Abdo, Youssef; Rohani, Vandad; Cauneau, François; Fulcheri, Laurent

    2017-02-01

    Interactions between an arc and external fields are crucially important for the design and the optimization of modern plasma torches. Multiple studies have been conducted to help better understand the behavior of DC and AC current arcs exposed to external and ‘self-induced’ magnetic fields, but the theoretical foundations remain very poorly explored. An analytical investigation has therefore been carried out in order to study the general behavior of DC and AC arcs under the effect of random cross-fields. A simple differential equation describing the general behavior of a planar DC or AC arc has been obtained. Several dimensionless numbers that depend primarily on arc and field parameters and the main arc characteristics (temperature, electric field strength) have also been determined. Their magnitude indicates the general tendency pattern of the arc evolution. The analytical results for many case studies have been validated using an MHD numerical model. The main purpose of this investigation was deriving a practical analytical model for the electric arc, rendering possible its stabilization and control, and the enhancement of the plasma torch power.

  18. Interrater reliability of the interRAI Acute Care (interRAI AC).

    PubMed

    Wellens, Nathalie I H; Van Lancker, Aurélie; Flamaing, Johan; Gray, Len; Moons, Philip; Verbeke, Geert; Boonen, Steven; Milisen, Koen

    2012-01-01

    We examined the interrater reliability of the interRAI AC. An observational study was conducted on 3 geriatric wards. Two trained raters completed independently the interRAI AC between 24 and 48 h after admission. A sample of 100 patients (age 84.5 ± 5.6 years; 45% female) was analyzed. Interrater reliability was tested using observed agreement, kappa coefficients, and intraclass correlation coefficients. The overall kappa median value for nominal items was 0.82 (almost perfect). For items on ordinal level, both the overall weighted kappa median and the intraclass correlation coefficient median were 0.86 (almost perfect). According to conventional cut-offs for interpreting kappa statistics, reliability was almost perfect (K ≥ 0.81) for 60% of all items, substantial (0.60 < K ≤ 0.80) for 26%, moderate (0.41 < K ≤ 0.60) for 10%, and poor (K ≤ 0.40) for 4% of the items. The median observed agreement was 0.89. For 83% of the items, the observed agreement was greater than 0.80. This study showed substantial or almost perfect interrater reliability for 86% of the items. In addition to previous evidence, the current results suggest that the estimates of the interrater reliability of the interRAI AC are acceptable and provide preliminary evidence that the current version is appropriate for clinical application.

  19. Impairment of liver synthetic function and the production of plasma proteins in primary breast cancer patients on doxorubicincyclophosphamide (AC) protocol.

    PubMed

    Saleem, Zikria; Ahmad, Mobasher; Hashmi, Furqan Khurshid; Saeed, Hamid; Aziz, Muhammad Tahir

    2016-09-01

    Doxorubicin and Cyclophosphamide (AC protocol) combination is usually considered as a first line therapy in newly diagnosed breast cancer patients. Thus, a retrospective observational study was conducted to monitor the effect of AC protocol on liver synthetic functions and production of plasma proteins in breast cancer patients, reporting to specialized cancer care hospital of Lahore, Pakistan. A total of 75 patients (n=75) on AC protocol with breast cancer were observed in this study. The patient data including age, gender, body surface area, dosage, disease status and laboratory biochemical values were recorded by reviewing historical treatment records. Pre-treatment values were taken as baseline values for albumin, globulin, blood urea nitrogen (BUN), albumin/globulin (A/G) ratio and total proteins. The baseline values were compared after each cycle of by applying ANOVA using statistical tool SPSS® version 21. The plasma levels of blood urea nitrogen (BUN), total protein and globulin dropped significantly (p<0.05) in patients of all age groups. However, the albumin levels were not significantly changed (p>0.05). The A/G ratio level increased (p<0.05) as a result of reduction in globulin levels. Significant changes in plasma protein levels were observed in the elderly patients (50 to 65 years) than patients between 20 to 50 years of age. AC protocol impairs liver synthetic functions as observed by decreased blood urea nitrogen (BUN) and plasma protein levels.

  20. A 52-week safety study in cynomolgus macaques for genetically modified rice expressing Cry1Ab/1Ac protein.

    PubMed

    Mao, Jie; Sun, Xing; Cheng, Jian-Hua; Shi, Yong-Jie; Wang, Xin-Zheng; Qin, Jun-Jie; Sang, Zhi-Hong; He, Kun; Xia, Qing

    2016-09-01

    A 52-week feeding study in cynomolgus macaques was carried out to evaluate the safety of Bt rice Huahui 1 (HH1), a transgenic rice line expressing Cry1Ab/1Ac protein. Monkeys were fed a diet with 20% or 60% HH1 rice, 20% or 60% parental rice (Minghui 63, MH63), normal diet, normal diet spiked with purified recombinant Cry1Ab/1Ac fusion protein or bovine serum albumin (BSA) respectively. During the feeding trail, clinical observations were conducted daily, and multiple parameters, including body weight, body temperature, electrocardiogram, hematology, blood biochemistry, serum metabolome and gut microbiome were examined at regular intervals. Upon sacrifice, the organs were weighted, and the macroscopic, microscopic and electron microscopic examinations were performed. The results show no adverse or toxic effects of Bt rice HH1 or Cry1Ab/1Ac fusion protein on monkeys. Therefore, the present 52-week primate feeding study suggests that the transgenic rice containing Cry 1Ab/1Ac is equivalent to its parental rice line MH63.

  1. Head-to-Head Comparison of Transcranial Random Noise Stimulation, Transcranial AC Stimulation, and Transcranial DC Stimulation for Tinnitus

    PubMed Central

    Vanneste, Sven; Fregni, Felipe; De Ridder, Dirk

    2013-01-01

    Tinnitus is the perception of a sound in the absence of an external sound stimulus. This phantom sound has been related to plastic changes and hyperactivity in the auditory cortex. Different neuromodulation techniques such as transcranial magnetic stimulation and transcranial direct current stimulation (tDCS) have been used in an attempt to modify local and distant neuroplasticity as to reduce tinnitus symptoms. Recently, two techniques of pulsed electrical stimulation using weak electrical currents – transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS) – have also shown significant neuromodulatory effects. In the present study we conducted the first head-to-head comparison of three different transcranial electrical stimulation (tES) techniques, namely tDCS, tACS, and tRNS in 111 tinnitus patients by placing the electrodes overlying the auditory cortex bilaterally. The results demonstrated that tRNS induced the larger transient suppressive effect on the tinnitus loudness and the tinnitus related distress as compared to tDCS and tACS. Both tDCS and tACS induced small and non-significant effects on tinnitus symptoms, supporting the superior effects of tRNS as a method for tinnitus suppression. PMID:24391599

  2. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    SciTech Connect

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  3. The 91-205 amino acid region of AcMNPV ORF34 (Ac34), which comprises a potential C3H zinc finger, is required for its nuclear localization and optimal virus multiplication.

    PubMed

    Qiu, Jianxiang; Tang, Zhimin; Yuan, Meijin; Wu, Wenbi; Yang, Kai

    2017-01-15

    During baculovirus infection, most viral proteins must be imported to the nucleus to support virus multiplication. Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf34 (ac34) is an alphabaculovirus unique gene that is required for optimal virus production. Ac34 distributes in both the cytoplasm and the nuclei of virus-infected Sf9 cells, but contains no conventional nuclear localization signal (NLS). In this study, we investigated the nuclear targeting domains in Ac34. Transient expression assays showed that Ac34 localized in both the cytoplasm and the nuclei of Sf9 cells, indicating that no viral protein is required for Ac34 nuclear localization. Subcellular localization analysis of Ac34 truncations and internal deletions fused with green fluorescent protein in plasmid-transfected Sf9 cells identified that the 91-205 amino acid (aa) region is required for Ac34 nuclear localization. Mutations in a potential C3H zinc finger (aa 116-131) in Ac34 resulted in exclusive cytoplasmic distribution of GFP:Ac34, suggesting that the zinc finger is required for Ac34 nuclear localization. To assess the functional importance of Ac34 in the nucleus during virus replication, recombinant AcMNPV bacmids containing a series of Ac34 truncations, internal deletions, or site mutations fused with HA tags were constructed. Subcellular localization analysis showed that Ac34 with internal deletions in aa 91-205 or site mutations in the potential zinc finger was predominantly distributed in the cytoplasm. Viral plaque assays and virus growth curves indicated that disruption of Ac34 nuclear localization significantly impaired virus replication. Taken together, our findings demonstrated that the nuclear localization of Ac34 requires the 91-205 aa region and its nuclear localization is essential for optimal virus replication.

  4. Results of Water and Sediment Toxicity Tests and Chemical Analyses Conducted at the Central Shops Burning Rubble Pit Waste Unit, January 1999

    SciTech Connect

    Specht, W.L.

    1999-06-02

    The Central Shops Burning Rubble Pit Operable Unit consists of two inactive rubble pits (631-1G and 631-3G) that have been capped, and one active burning rubble pit (631-2G), where wooden pallets and other non-hazardous debris are periodically burned. The inactive rubble pits may have received hazardous materials, such as asbestos, batteries, and paint cans, as well as non-hazardous materials, such as ash, paper, and glass. In an effort to determine if long term surface water flows of potentially contaminated water from the 631-1G, 631-3G, and 631-2G areas have resulted in an accumulation of chemical constituents at toxic levels in the vicinity of the settling basin and wetlands area, chemical analyses for significant ecological preliminary constituents of concern (pCOCs) were performed on aqueous and sediment samples. In addition, aquatic and sediment toxicity tests were performed in accordance with U.S. EPA methods (U.S. EPA 1989, 1994). Based on the results of the chemical analyses, unfiltered water samples collected from a wetland and settling basins located adjacent to the CSBRP Operable Unit exceed Toxicity Reference Values (TRVs) for aluminum, barium, chromium, copper, iron, lead, and vanadium at one or more of the four locations that were sampled. The water contained very high concentrations of clay particles that were present as suspended solids. A substantial portion of the metals were present as filterable particulates, bound to the clay particles, and were therefore not biologically available. Based on dissolved metal concentrations, the wetland and settling basin exceeded TRVs for aluminum and barium. However, the background reference location also exceeded the TRV for barium, which suggests that this value may be too low, based on local geochemistry. The detection limits for both total and dissolved mercury were higher than the TRV, so it was not possible to determine if the TRV for mercury was exceeded. Dissolved metal levels of chromium, copper

  5. Communication: Dimensionality of the ionic conduction pathways in glass and the mixed-alkali effect.

    PubMed

    Novy, Melissa; Avila-Paredes, Hugo; Kim, Sangtae; Sen, Sabyasachi

    2015-12-28

    A revised empirical relationship between the power law exponent of ac conductivity dispersion and the dimensionality of the ionic conduction pathway is established on the basis of electrical impedance spectroscopic (EIS) measurements on crystalline ionic conductors. These results imply that the "universal" ac conductivity dispersion observed in glassy solids is associated with ionic transport along fractal pathways. EIS measurements on single-alkali glasses indicate that the dimensionality of this pathway D is ∼2.5, while in mixed-alkali glasses, D is lower and goes through a minimum value of ∼2.2 when the concentrations of the two alkalis become equal. D and σ display similar variation with alkali composition, thus suggesting a topological origin of the mixed-alkali effect.

  6. Results of the second Round Robin on opening-load measurement conducted by ASTM Task Group E24.04.04 on crack closure measurement and analysis

    NASA Technical Reports Server (NTRS)

    Phillips, E. P.

    1993-01-01

    A second experimental Round Robin on the measurement of the crack opening load in fatigue crack growth tests has been completed by the ASTM Task Group E24.04.04 on Crack Closure Measurement and Analysis. Fourteen laboratories participated in the testing of aluminum alloy compact tension specimens. Opening-load measurements were made at three crack lengths during constant Delta K, constant stress ratio tests by most of the participants. Four participants made opening-load measurements during threshold tests. All opening-load measurements were based on the analysis of specimens compliance behavior, where the displacement/strain was measured either at the crack mouth or the mid-height back face location. The Round Robin data were analyzed for opening load using two non-subjective analysis methods: the compliance offset and the correlation coefficient methods. The scatter in the opening load results was significantly reduced when some of the results were excluded from the analysis population based on an accept/reject criterion for raw data quality. The compliance offset and correlation coefficient opening load analysis methods produced similar results for data populations that had been screened to eliminate poor quality data.

  7. Electrical Conductivity.

    ERIC Educational Resources Information Center

    Hershey, David R.; Sand, Susan

    1993-01-01

    Explains how electrical conductivity (EC) can be used to measure ion concentration in solutions. Describes instrumentation for the measurement, temperature dependence and EC, and the EC of common substances. (PR)

  8. AC power system breadboard

    NASA Technical Reports Server (NTRS)

    Wappes, Loran J.; Sundberg, R.; Mildice, J.; Peterson, D.; Hushing, S.

    1987-01-01

    The object of this program was to design, build, test, and deliver a high-frequency (20-kHz) Power System Breadboard which would electrically approximate a pair of dual redundant power channels of an IOC Space Station. This report describes that program, including the technical background, and discusses the results, showing that the major assumptions about the characteristics of this class of hardware (size, mass, efficiency, control, etc.) were substantially correct. This testbed equipment has been completed and delivered to LeRC, where it is operating as a part of the Space Station Power System Test Facility.

  9. ACS Nearby Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Dalcanton, Julianne

    2006-07-01

    Existing HST observations of nearby galaxies comprise a sparse and highly non-uniform archive, making comprehensive comparative studies among galaxies essentially impossible. We propose to secure HST's lasting impact on the study of nearby galaxies by undertaking a systematic, complete, and carefully crafted imaging survey of ALL galaxies in the Local Universe outside the Local Group. The resulting images will allow unprecedented measurements of: {1} the star formation history {SFH} of a >100 Mpc^3 volume of the Universe with a time resolution of Delta[log{t}]=0.25; {2} correlations between spatially resolved SFHs and environment; {3} the structure and properties of thick disks and stellar halos; and {4} the color distributions, sizes, and specific frequencies of globular and disk clusters as a function of galaxy mass and environment. To reach these goals, we will use a combination of wide-field tiling and pointed deep imaging to obtain uniform data on all 72 galaxies within a volume-limited sample extending to 3.5 Mpc, with an extension to the M81 group. For each galaxy, the wide-field imaging will cover out to 1.5 times the optical radius and will reach photometric depths of at least 2 magnitudes below the tip of the red giant branch throughout the limits of the survey volume. One additional deep pointing per galaxy will reach SNR 10 for red clump stars, sufficient to recover the ancient SFH from the color-magnitude diagram. This proposal will produce photometric information for 100 million stars {comparable to the number in the SDSS survey} and uniform multi-color images of half a square degree of sky. The resulting archive will establish the fundamental optical database for nearby galaxies, in preparation for the shift of high-resolution imaging to the near-infrared.

  10. Resonant AC power system proof-of-concept test program

    NASA Technical Reports Server (NTRS)

    Wappes, Loran J.

    1986-01-01

    Proof-of-concept testing was performed on a 20-kHz, resonant power system breadboard from 1981 through 1985. The testing began with the evaluation of a single, 1.0-kW resonant inverter and progressed to the testing of breadboard systems with higher power levels and more capability. The final breadboard configuration tested was a 25.0-kW breadboard with six inverters providing power to three user-interface modules over a 50-meter, 20-kHz bus. The breadboard demonstrated the ability to synchronize multiple resonant inverters to power a common bus. Single-phase and three-phase 20-kHz power distribution was demonstrated. Simple conversion of 20-kHz to dc and variable-frequency ac was demonstrated as was bidirectional power flow between 20-kHz and dc. Steady state measurements of efficiency, power-factor tolerance, and conducted emissions and conducted susceptibility were made. In addition, transient responses were recorded for such conditions as start up, shut down, load changes. The results showed the 20-kHz resonant system to be a desirable technology for a spacecraft power management and distribution system with multiple users and a utility-type bus.

  11. Sensitivity analysis on an AC600 aluminum skin component

    NASA Astrophysics Data System (ADS)

    Mendiguren, J.; Agirre, J.; Mugarra, E.; Galdos, L.; Saenz de Argandoña, E.

    2016-08-01

    New materials are been introduced on the car body in order to reduce weight and fulfil the international CO2 emission regulations. Among them, the application of aluminum alloys is increasing for skin panels. Even if these alloys are beneficial for the car design, the manufacturing of these components become more complex. In this regard, numerical simulations have become a necessary tool for die designers. There are multiple factors affecting the accuracy of these simulations e.g. hardening, anisotropy, lubrication, elastic behavior. Numerous studies have been conducted in the last years on high strength steels component stamping and on developing new anisotropic models for aluminum cup drawings. However, the impact of the correct modelling on the latest aluminums for the manufacturing of skin panels has been not yet analyzed. In this work, first, the new AC600 aluminum alloy of JLR-Novelis is characterized for anisotropy, kinematic hardening, friction coefficient, elastic behavior. Next, a sensitivity analysis is conducted on the simulation of a U channel (with drawbeads). Then, the numerical an experimental results are correlated in terms of springback and failure. Finally, some conclusions are drawn.

  12. Magnetostrictive materials and method for improving AC characteristics in same

    DOEpatents

    Pulvirenti, Patricia P.; Jiles, David C.

    2001-08-14

    The present invention provides Terfenol-D alloys ("doped" Terfenol) having optimized performances under the condition of time-dependent magnetic fields. In one embodiment, performance is optimized by lowering the conductivity of Terfenol, thereby improving the frequency response. This can be achieved through addition of Group III or IV elements, such as Si and Al. Addition of these types of elements provides scattering sites for conduction electrons, thereby increasing resistivity by 125% which leads to an average increase in penetration depth of 80% at 1 kHz and an increase in energy conversion efficiency of 55%. The permeability of doped Terfenol remains constant over a wider frequency range as compared with undoped Terfenol. These results demonstrate that adding impurities, such as Si and Al, are effective in improving the ac characteristics of Terfenol. A magnetoelastic Gruneisen parameter, .gamma..sub.me, has also been derived from the thermodynamic equations of state, and provides another means by which to characterize the coupling efficiency in magnetostrictive materials on a more fundamental basis.

  13. The ACS Nearby Galaxy Survey Treasury

    NASA Astrophysics Data System (ADS)

    Dalcanton, Julianne; Williams, B.; Gogarten, S.; Weisz, D.; Skillman, E.; Seth, A.; ANGST Team

    2007-12-01

    The ACS Nearby Galaxy Survey Treasury program (ANGST) is a program to measure photometry for millions of stars in a volume limited sample of 70 nearby galaxies. With this data set, we are deriving spatially resolved star formation histories for both dwarfs and spirals in the local volume. I will highlight initial results from the survey, including ancient star formation histories for massive spirals, halos around dwarf galaxies, spatially-resolved star formation histories in dwarfs and spirals, and the detection of variable stars. I will also discuss the ANGST involved with switching to WFPC2. This program is funded by NASA grant HST GO-10915, administered by STScI.

  14. 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.

  15. Mapping the conformational epitope of a neutralizing antibody (AcV1) directed against the AcMNPV GP64 protein

    SciTech Connect

    Zhou Jian; Blissard, Gary W. . E-mail: gwb1@cornell.edu

    2006-09-01

    The envelope glycoprotein GP64 of Autographa californica nucleopolyhedrovirus (AcMNPV) is necessary and sufficient for the acid-induced membrane fusion activity that is required for fusion of the budded virus (BV) envelope and the endosome membrane during virus entry. Infectivity of the budded virus (BV) is neutralized by AcV1, a monoclonal antibody (MAb) directed against GP64. Prior studies indicated that AcV1 recognizes a conformational epitope and does not inhibit virus attachment to the cell, but instead inhibits entry at a step following virus attachment. We found that AcV1 recognition of GP64 was lost upon exposure of GP64 to low pH (pH 4.5) and restored by returning GP64 to pH 6.2. In addition, the AcV1 epitope was lost upon denaturation of GP64 in SDS, but the AcV1 epitope was restored by refolding the protein in the absence of SDS. Using truncated GP64 proteins expressed in insect cells, we mapped the AcV1 epitope to a 24 amino acid region in the central variable domain of GP64. When sequences within the mapped AcV1 epitope were substituted with a c-Myc epitope and the resulting construct was used to replace wt GP64 in recombinant AcMNPV viruses, the modified GP64 protein appeared to function normally. However, an anti-c-Myc monoclonal antibody did not neutralize infectivity of those viruses. Because binding of the c-Myc MAb to the same site in the GP64 sequence did not result in neutralization, these studies suggest that AcV1 neutralization may result from a specific structural constraint caused by AcV1 binding and not simply by steric hindrance caused by antibody binding at this position in GP64.

  16. Baseline Trachoma Surveys in Kaskazini A and Micheweni Districts of Zanzibar: Results of Two Population-Based Prevalence Surveys Conducted with the Global Trachoma Mapping Project

    PubMed Central

    Omar, Fatma J.; Kabona, George; Abdalla, Khalfan M.; Mohamed, Saleh J.; Ali, Said M.; Ame, Shaali M.; Ngwalle, Abel; Mbise, Christina; Rotondo, Lisa; Willis, Rebecca; Flueckiger, Rebecca M.; Massae, Patrick A.; Bakhtiari, Ana; Solomon, Anthony W.; Ngondi, Jeremiah M.

    2016-01-01

    ABSTRACT Purpose: Based on health care records and trachoma rapid assessments, trachoma was suspected to be endemic in Kaskazini A and Micheweni districts of Zanzibar. This study aimed to investigate the prevalence of trachomatous inflammation–follicular (TF), and trachomatous trichiasis (TT) in each of those districts. Methods: The survey was undertaken in Kaskazini A and Micheweni districts on Unguja and Pemba Islands, respectively. A multi-stage cluster random sampling design was applied, whereby 25 census enumeration areas (clusters) and 30 households per cluster were included. Consenting eligible participants (children aged 1–9 years and people aged 15 years and older) were examined for trachoma using the World Health Organization simplified grading system. Results: A total of 1673 households were surveyed and 6407 participants (98.0% of those enumerated) were examined for trachoma. Examinees included a total of 2825 children aged 1–9 years and 3582 people aged 15 years and older. TF prevalence in 1–9-year-olds was 2.7% (95% confidence interval, CI, 2.7–4.1%) in Kazkazini A and 11.4% (95% CI 6.6–16.5%) in Micheweni. Among people aged 15 years and older, TT prevalence was 0.01% (95% CI 0.00–0.04%) in Kazkazini A and 0.21% (95% CI 0.08–0.39%) in Micheweni. Conclusion: Trachoma is a public health problem in Micheweni district, where implementation of all four components of the SAFE strategy (surgery, antibiotics, facial cleanliness, and environmental improvement), including mass drug administration with azithromycin, is required. These findings will facilitate planning for trachoma elimination. PMID:27775454

  17. Factors associated with dog rabies vaccination in Bhol, Philippines: results of a cross-sectional cluster survey conducted following the island-wide rabies elimination campaign.

    PubMed

    Davlin, S; Lapiz, S M; Miranda, M E; Murray, K

    2013-11-01

    The Philippines has a long history of rabies control efforts in their dog populations; however, long-term success of such programmes and the goal of rabies elimination have not yet been realized. The Bohol Rabies Prevention and Elimination Program was developed as an innovative approach to canine rabies control in 2007. The objective of this study was to assess canine rabies vaccination coverage in the owned-dog population in Bohol and to describe factors associated with rabies vaccination 2 years after implementation of the programme. We utilized a cross-sectional cluster survey based on the World Health Organization's Expanded Programme on Immunization coverage survey technique. We sampled 460 households and collected data on 539 dogs residing within these households. Seventy-seven per cent of surveyed households reported owning at least one dog. The human-to-dog ratio was approximately 4 : 1, and the mean number of dogs owned per household was 1.6. Based on this ratio, we calculated an owned-dog population of almost 300 000. Overall, 71% of dogs were reported as having been vaccinated for rabies at some time in their lives; however, only 64% of dogs were reported as having been recently vaccinated. Dogs in our study were young (median age = 24 months). The odds of vaccination increased with increasing age. Dogs aged 12-23 months had 4.6 times the odds of vaccination compared to dogs aged 3-11 months (95% CI 1.8-12.0; P = 0.002). Confinement of the dog both day and night was also associated with increased odds of vaccination (OR = 2.1; 95% CI 0.9-4.9; P = 0.07), and this result approached statistical significance. While the programme is on track to meet its goal of 80% vaccination coverage, educational efforts should focus on the need to confine dogs and vaccinate young dogs.

  18. Selected Health Conditions Among Overweight, Obese, and Non-Obese Veterans of the 1991 Gulf War: Results from a Survey Conducted in 2003-2005.

    PubMed

    Coughlin, Steven S; Kang, Han K; Mahan, Clare M

    2011-01-01

    BACKGROUND: Several health conditions and concerns have been reported to be increased among Gulf War veterans including post-traumatic stress disorder (PTSD), chronic fatigue syndrome (CFS), CFS-like illness, and unexplained multi-symptom illness (MSI). As the cohort of Gulf War veterans advance in age, they are likely to be at risk of not only certain deployment-related health conditions but also chronic diseases associated with lifestyle factors. METHODS: To clarify relationships between PTSD, CFS-like illness, MSI, and obesity, we analyzed data from a cross-sectional survey of health information among population-based samples of 15,000 Gulf War veterans and 15,000 veterans who served during the same era. Data had been collected from 9,970 respondents in 2003-2005 via a structured questionnaire or telephone survey. RESULTS: Based upon body mass index (BMI) estimated from self-reported information about height and weight, the percentages of Gulf War and Gulf Era veterans who were overweight (BMI 25 to ≤ 29.9), were 46.8% and 48.7%, respectively. The percentages who were obese (BMI ≥ 30) were 29.6% and 28.3%, respectively. Without adjustment for Gulf deployment status (Gulf War vs Gulf Era), age, sex, or other factors, PTSD, MSI, CFS-like illness, and other chronic health conditions were more common among obese veterans than those who were normal weight (BMI 18.5 to ≤ 24.9). In multivariate analyses, PTSD was positively associated with obesity after adjustment for age, sex, Gulf deployment status, rank, income, education, and current smoking. In the model for PTSD, the adjusted odds ratio for obesity was 1.5 (95% CI 1.2-1.8). No associations were observed between BMI categories and CFS-like illness or MSI in multivariate analysis. CONCLUSIONS: Gulf War and Gulf Era veterans who were obese were more likely to have certain chronic health conditions including PTSD. Associations between Gulf status and CFS-like illness and MSI identified in the 2003-2005 follow

  19. Bcl-2△21 and Ac-DEVD-CHO Inhibit Death of Wheat Microspores

    PubMed Central

    Sinha, Rakesh K.; Pospíšil, Pavel; Maheshwari, Priti; Eudes, François

    2016-01-01

    Microspore cell death and low green plant production efficiency are an integral obstacle in the development of doubled haploid production in wheat. The aim of the current study was to determine the effect of anti-apoptotic recombinant human B-cell lymphoma-2 (Bcl-2△21) and caspase-3-inhibitor (Ac-DEVD-CHO) in microspore cell death in bread wheat cultivars AC Fielder and AC Andrew. Induction medium containing Bcl-2△21 and Ac-DEVD-CHO yielded a significantly higher number of viable microspores, embryo-like structures and total green plants in wheat cultivars AC Fielder and AC Andrew. Total peroxidase activity was lower in Bcl-2△21 treated microspore cultures at 96 h of treatment compared to control and Ac-DEVD-CHO. Electron paramagnetic resonance study of total microspore protein showed a different scavenging activity for Bcl-2△21 and Ac-DEVD-CHO. Bcl-2△21 scavenged approximately 50% hydroxyl radical (HO•) formed, whereas Ac-DEVD-CHO scavenged approximately 20% of HO•. Conversely, reduced caspase-3-like activities were detected in the presence of Bcl-2△21 and Ac-DEVD-CHO, supporting the involvement of Bcl-2△21 and Ac-DEVD-CHO in increasing microspore viability by reducing oxidative stress and caspase-3-like activity. Our results indicate that Bcl-2△21 and Ac-DEVD-CHO protects cells from cell death following different pathways. Bcl-2△21 prevents cell damage by detoxifying HO• and suppressing caspase-3-like activity, while Ac-DEVD-CHO inhibits the cell death pathways by modulating caspase-like activity. PMID:28082995

  20. Bcl-2△21 and Ac-DEVD-CHO Inhibit Death of Wheat Microspores.

    PubMed

    Sinha, Rakesh K; Pospíšil, Pavel; Maheshwari, Priti; Eudes, François

    2016-01-01

    Microspore cell death and low green plant production efficiency are an integral obstacle in the development of doubled haploid production in wheat. The aim of the current study was to determine the effect of anti-apoptotic recombinant human B-cell lymphoma-2 (Bcl-2△21) and caspase-3-inhibitor (Ac-DEVD-CHO) in microspore cell death in bread wheat cultivars AC Fielder and AC Andrew. Induction medium containing Bcl-2△21 and Ac-DEVD-CHO yielded a significantly higher number of viable microspores, embryo-like structures and total green plants in wheat cultivars AC Fielder and AC Andrew. Total peroxidase activity was lower in Bcl-2△21 treated microspore cultures at 96 h of treatment compared to control and Ac-DEVD-CHO. Electron paramagnetic resonance study of total microspore protein showed a different scavenging activity for Bcl-2△21 and Ac-DEVD-CHO. Bcl-2△21 scavenged approximately 50% hydroxyl radical (HO(•)) formed, whereas Ac-DEVD-CHO scavenged approximately 20% of HO(•). Conversely, reduced caspase-3-like activities were detected in the presence of Bcl-2△21 and Ac-DEVD-CHO, supporting the involvement of Bcl-2△21 and Ac-DEVD-CHO in increasing microspore viability by reducing oxidative stress and caspase-3-like activity. Our results indicate that Bcl-2△21 and Ac-DEVD-CHO protects cells from cell death following different pathways. Bcl-2△21 prevents cell damage by detoxifying HO(•) and suppressing caspase-3-like activity, while Ac-DEVD-CHO inhibits the cell death pathways by modulating caspase-like activity.

  1. Developing Test Apparatus and Measurements of AC Loss of High Temperature Superconductors

    DTIC Science & Technology

    2012-11-01

    superconducting wires can be very effectively reduced in proportion of the number of filaments. The oxygen annealing eliminates the residual coupling losses by...made out of YBCO superconducting wires were studied, confirming the simulation method used to calculate and predict AC loss and hysteretic effects of... oxygen annealing were tested in order to determine their effect on AC loss reduction. Results showed that the AC loss in multifilament

  2. Reliability of emergency ac power systems at nuclear power plants

    SciTech Connect

    Battle, R E; Campbell, D J

    1983-07-01

    Reliability of emergency onsite ac power systems at nuclear power plants has been questioned within the Nuclear Regulatory Commission (NRC) because of the number of diesel generator failures reported by nuclear plant licensees and the reactor core damage that could result from diesel failure during an emergency. This report contains the results of a reliability analysis of the onsite ac power system, and it uses the results of a separate analysis of offsite power systems to calculate the expected frequency of station blackout. Included is a design and operating experience review. Eighteen plants representative of typical onsite ac power systems and ten generic designs were selected to be modeled by fault trees. Operating experience data were collected from the NRC files and from nuclear plant licensee responses to a questionnaire sent out for this project.

  3. Appropriate Conduct

    ERIC Educational Resources Information Center

    Di Lullo, Louis

    2004-01-01

    Many years ago when the author assumed the role of assistant principal for school climate, discipline, and attendance, he inherited many school policies and guidelines that were outdated, unfair, and without merit in the current school climate. Because the school conduct code had not been revised since the school opened in 1960, many of the…

  4. High temperature conductivity of potassium-beta(double prime)-alumina

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Jeffries-Nakamura, B.; Underwood, M. L.; Ryan, M. A.; O'Connor, D.; Kikkert, S.

    1992-01-01

    Potassium beta(double prime)-alumina (BDPA) single crystals have been reported by several groups to leave higher ionic conductivity than sodium BDPA crystals at room temperature, and similar conductivities are obtained at temperatures up to 600-700 K. Potassium BDPA ceramics have been reported to have significantly poorer conductivities than those of sodium BDPA ceramics, but conductivity measurements at temperatures above 625 K have not been reported. In this study, K(+)-BDPA ceramics were prepared from Na(+)-BDPA ceramic using a modified version of the exchange reaction with KCl vapor reported by Crosbie and Tennenhouse (1982), and the conductivity has been measured in K vapor at temperatures up to 1223 K, using the method of Cole et al. (1979). The results indicate reasonable agreement with earlier data on K(+)-BDPA ceramic measured in a liquid K cell, but show that the K(+)-BDPA ceramic's conductivity approaches that of Na(+)-BDPA ceramic at higher temperatures, being within a factor of four at 700 K and 60 percent of the conductivity of Na(+)-BDPA at T over 1000 K. Both four-probe dc conductivity and four probe ac impedance measurements were used to characterize the conductivity. A rather abrupt change in the grain boundary resistance suggesting a possible phase change in the intergranular material, potassium aluminate, is seen in the ac impedance behavior.

  5. Slug Test Characterization Results for Multi-Test/Depth Intervals Conducted During the Drilling of CERCLA Operable Unit OU ZP-1 Wells 299-W10-33 and 299-W11-48

    SciTech Connect

    Newcomer, Darrell R.

    2007-09-30

    Slug-test results obtained from single and multiple, stress-level slug tests conducted during drilling and borehole advancement provide detailed hydraulic conductivity information at two Hanford Site Operable Unit (OU) ZP-1 test well locations. The individual test/depth intervals were generally sited to provide hydraulic-property information within the upper ~10 m of the unconfined aquifer (i.e., Ringold Formation, Unit 5). These characterization results complement previous and ongoing drill-and-test characterization programs at surrounding 200-West and -East Area locations (see Figure S.1).

  6. AC impedance electrochemical modeling of lithium-ion positive electrodes.

    SciTech Connect

    Dees, D.; Gunen, E.; Abraham, D.; Jansen, A.; Prakash, J.; Chemical Engineering; IIT

    2004-01-01

    Under Department of Energy's Advanced Technology Development Program,various analytical diagnostic studies are being carried out to examine the lithium-ion battery technology for hybrid electric vehicle applications, and a series of electrochemical studies are being conducted to examine the performance of these batteries. An electrochemical model was developed to associate changes that were observed in the post-test analytical diagnostic studies with the electrochemical performance loss during testing of lithium ion batteries. While both electrodes in the lithium-ion cell have been studied using a similar electrochemical model, the discussion here is limited to modeling of the positive electrode. The positive electrode under study has a composite structure made of a layered nickel oxide (LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}) active material, a carbon black and graphite additive for distributing current, and a PVDF binder all on an aluminum current collector. The electrolyte is 1.2M LiPF{sub 6} dissolved in a mixture of EC and EMC and a Celgard micro-porous membrane is used as the separator. Planar test cells (positive/separator/negative) were constructed with a special fixture and two separator membranes that allowed the placement of a micro-reference electrode between the separator membranes [1]. Electrochemical studies including AC impedance spectroscopy were then conducted on the individual electrodes to examine the performance and ageing effects in the cell. The model was developed by following the work of Professor Newman at Berkeley [2]. The solid electrolyte interface (SEI) region, based on post-test analytical results, was assumed to be a film on the oxide and an oxide layer at the surface of the oxide. A double layer capacity was added in parallel with the Butler-Volmer kinetic expression. The pertinent reaction, thermodynamic, and transport equations were linearized for a small sinusoidal perturbation [3]. The resulting system of differential

  7. AcMNPV-mediated expression of BmK IT promotes the apoptosis of Sf9 cells and replication of AcMNPV.

    PubMed

    Fu, Yue-Jun; Zhao, Jie; Liang, Ai-Hua; Hu, Feng-Yun

    2015-06-25

    Chinese scorpion Buthus martensii Karsch (BmK) venom is a rich source of neurotoxins which bind to various ion channels with high affinity and specificity and thus widely used as compounds to modulate channel gating or channel currents. To promote the insecticidal effects of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), the gene encoding an excitatory insect toxin, BmK IT, was inserted into the genome of AcMNPV to construct a recombinant baculovirus, AcMNPV-BmK IT. Spodopter frugiperda 9 (Sf9) cells were infected with AcMNPV and AcMNPV-BmK IT respectively for 24 h. Results from the MTT assay, TUNEL assay, analysis of the expression level of apoptosis-related proteins (c-Myc, cleaved-Caspase3, Bcl-2 and Bax) of Sf9 cells, the transcription level of key genes (38K, C42, P78, F) of AcMNPV, and viral propagation assay demonstrated that AcMNPV-mediated expression of BmK IT promoted the apoptosis of Sf9 cells and replication of AcMNPV. The results laid a foundation for further structural and functional analysis of BmK IT.

  8. The effect of bone conduction microphone placement on intensity and spectrum of transmitted speech items.

    PubMed

    Tran, Phuong K; Letowski, Tomasz R; McBride, Maranda E

    2013-06-01

    Speech signals can be converted into electrical audio signals using either conventional air conduction (AC) microphone or a contact bone conduction (BC) microphone. The goal of this study was to investigate the effects of the location of a BC microphone on the intensity and frequency spectrum of the recorded speech. Twelve locations, 11 on the talker's head and 1 on the collar bone, were investigated. The speech sounds were three vowels (/u/, /a/, /i/) and two consonants (/m/, /∫/). The sounds were produced by 12 talkers. Each sound was recorded simultaneously with two BC microphones and an AC microphone. Analyzed spectral data showed that the BC recordings made at the forehead of the talker were the most similar to the AC recordings, whereas the collar bone recordings were most different. Comparison of the spectral data with speech intelligibility data collected in another study revealed a strong negative relationship between BC speech intelligibility and the degree of deviation of the BC speech spectrum from the AC spectrum. In addition, the head locations that resulted in the highest speech intelligibility were associated with the lowest output signals among all tested locations. Implications of these findings for BC communication are discussed.

  9. Identification of Autographa californica nucleopolyhedrovirus ac93 as a core gene and its requirement for intranuclear microvesicle formation and nuclear egress of nucleocapsids.

    PubMed

    Yuan, Meijin; Huang, Zhenqiu; Wei, Denghui; Hu, Zhaoyang; Yang, Kai; Pang, Yi

    2011-11-01

    Autographa californica nucleopolyhedrovirus (AcMNPV) orf93 (ac93) is a highly conserved uncharacterized gene that is found in all of the sequenced baculovirus genomes except for Culex nigripalpus NPV. In this report, using bioinformatics analyses, ac93 and odv-e25 (ac94) were identified as baculovirus core genes and thus p33-ac93-odv-e25 represent a cluster of core genes. To investigate the role of ac93 in the baculovirus life cycle, an ac93 knockout AcMNPV bacmid was constructed via homologous recombination in Escherichia coli. Fluorescence and light microscopy showed that the AcMNPV ac93 knockout did not spread by infection, and titration assays confirmed a defect in budded virus (BV) production. However, deletion of ac93 did not affect viral DNA replication. Electron microscopy indicated that ac93 was required for the egress of nucleocapsids from the nucleus and the formation of intranuclear microvesicles, which are precursor structures of occlusion-derived virus (ODV) envelopes. Immunofluorescence analyses showed that Ac93 was concentrated toward the cytoplasmic membrane in the cytoplasm and in the nuclear ring zone in the nucleus. Western blot analyses showed that Ac93 was associated with both nucleocapsid and envelope fractions of BV, but only the nucleocapsid fraction of ODV. Our results suggest that ac93, although not previously recognized as a core gene, is one that plays an essential role in the formation of the ODV envelope and the egress of nucleocapsids from the nucleus.

  10. DC bias effect on alternating current electrical conductivity of poly(ethylene terephthalate)/alumina nanocomposites

    NASA Astrophysics Data System (ADS)

    Nikam, Pravin N.; Deshpande, Vineeta D.

    2016-05-01

    Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al2O3) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observed at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivityAC) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher's universal power law of solids. It revealed that σAC of PET/alumina nanocomposites can be well characterized by the DC conductivity (σDC), critical frequency (ωc), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σDC) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.

  11. Space charge and charge trapping characteristics of cross-linked polyethylene subjected to ac electric stresses

    NASA Astrophysics Data System (ADS)

    Chong, Y. L.; Chen, G.; Miyake, H.; Matsui, K.; Tanaka, Y.; Takada, T.

    2006-04-01

    This paper reports on the result of space charge evolution in cross-linked polyethylene (XLPE) planar samples approximately 220 µm thick. The space charge measurement technique used in this study is the pulsed electroacoustic method. There are two phases to this experiment. In the first phase, the samples were subjected to dc 30 kVdc mm-1 and ac (sinusoidal) electric stress levels of 30 kVpk mm-1 at frequencies of 1, 10 and 50 Hz ac. In addition, ac space charge under 30 kVrms mm-1 and 60 kVpk mm-1 electric stress at 50 Hz was also investigated. The volts-off results showed that the amount of charge trapped in XLPE sample under dc electric stress is significantly bigger than samples under ac stress even when the applied ac stresses are substantially higher. The second phase of the experiment involves studying the dc space charge evolution in samples that were tested under ac stress during the first phase of the experiment. Ac ageing causes positive charge to become more dominant over negative charge. It was also discovered that ac ageing creates deeper traps, particularly for negative charge. This paper also gives a brief overview of the data processing methods used to analyse space charge under ac electric stress.

  12. AC Impedance Studies on Metal/Nanoporous Silicon/ p-Silicon Structures

    NASA Astrophysics Data System (ADS)

    Mabrook, M. F.; Ray, A. K.

    2017-04-01

    Alternating current (AC) impedance measurements have been performed on 10- to 15- μm thick porous silicon layers on a (100) p-type silicon ( p(+)Si) substrate with the aluminium (Al) top electrode in a sandwich configuration in the range of 20 Hz-1 MHz and in the temperature ranging between 152 K and 292 K. The ac conductivity σ ac was found to increase with frequency f according to the universal power law: σ_{{ac}} = Afs where the exponent s is a frequency and temperature-dependent quantity. A hopping process is found to be dominant at low temperatures and high frequencies, while a thermally activated free band process is responsible for conduction at higher temperatures. Capacitance is found to decrease with frequency but increase with temperature. Frequency dependence of the loss tangent is observed with a temperature-dependent minimum value.

  13. AC Impedance Studies on Metal/Nanoporous Silicon/p-Silicon Structures

    NASA Astrophysics Data System (ADS)

    Mabrook, M. F.; Ray, A. K.

    2016-11-01

    Alternating current (AC) impedance measurements have been performed on 10- to 15-μm thick porous silicon layers on a (100) p-type silicon (p(+)Si) substrate with the aluminium (Al) top electrode in a sandwich configuration in the range of 20 Hz-1 MHz and in the temperature ranging between 152 K and 292 K. The ac conductivity σ ac was found to increase with frequency f according to the universal power law: σ_{ac} = Afs where the exponent s is a frequency and temperature-dependent quantity. A hopping process is found to be dominant at low temperatures and high frequencies, while a thermally activated free band process is responsible for conduction at higher temperatures. Capacitance is found to decrease with frequency but increase with temperature. Frequency dependence of the loss tangent is observed with a temperature-dependent minimum value.

  14. AC Zeeman potentials for atom chip-based ultracold atoms

    NASA Astrophysics Data System (ADS)

    Fancher, Charles; Pyle, Andrew; Ziltz, Austin; Aubin, Seth

    2015-05-01

    We present experimental and theoretical progress on using the AC Zeeman force produced by microwave magnetic near-fields from an atom chip to manipulate and eventually trap ultracold atoms. These AC Zeeman potentials are inherently spin-dependent and can be used to apply qualitatively different potentials to different spin states simultaneously. Furthermore, AC Zeeman traps are compatible with the large DC magnetic fields necessary for accessing Feshbach resonances. Applications include spin-dependent trapped atom interferometry and experiments in 1D many-body physics. Initial experiments and results are geared towards observing the bipolar detuning-dependent nature of the AC Zeeman force at 6.8 GHz with ultracold 87Rb atoms trapped in the vicinity of an atom chip. Experimental work is also underway towards working with potassium isotopes at frequencies of 1 GHz and below. Theoretical work is focused on atom chip designs for AC Zeeman traps produced by magnetic near-fields, while also incorporating the effect of the related electric near-fields. Electromagnetic simulations of atom chip circuits are used for mapping microwave propagation in on-chip transmission line structures, accounting for the skin effect, and guiding impedance matching.

  15. AC propulsion system for an electric vehicle, phase 2

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1983-01-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  16. An ac electroosmosis device for the detection of bioparticles with piezoresistive microcantilever sensors

    NASA Astrophysics Data System (ADS)

    Arefin, Md Shamsul; Porter, Timothy L.

    2012-03-01

    This work reports on the behavior of piezoresistive microcantilever sensors under optimizing conditions of ac electroosmotic enhancement. Piezoresistive microcantilevers are used as sensor elements for detection of concentrated bio-particles. Without preconcentrating the samples, using ac electroosmosis, these bio-particles have been manipulated onto the piezoresistive microcantilever. A piezoresistive microcantilever senses the dimensional changes upon particle exposure as a resistance change. This paper represents the integration of ac electroosmosis with a piezoresistive micro-cantilever sensor for the detection of bio-particles. A working prototype is presented here, and the experiments are conducted on Herpes Simplex type-1 virus (HSV-1) and Escherichia Coli (E. coli) bacteria.

  17. System and component design and test of a 10 hp, 18,000 rpm AC dynamometer utilizing a high frequency AC voltage link, part 1

    NASA Technical Reports Server (NTRS)

    Lipo, Thomas A.; Alan, Irfan

    1991-01-01

    Hard and soft switching test results conducted with one of the samples of first generation MOS-controlled thyristor (MCTs) and similar test results with several different samples of second generation MCT's are reported. A simple chopper circuit is used to investigate the basic switching characteristics of MCT under hard switching and various types of resonant circuits are used to determine soft switching characteristics of MCT under both zero voltage and zero current switching. Next, operation principles of a pulse density modulated converter (PDMC) for three phase (3F) to 3F two-step power conversion via parallel resonant high frequency (HF) AC link are reviewed. The details for the selection of power switches and other power components required for the construction of the power circuit for the second generation 3F to 3F converter system are discussed. The problems encountered in the first generation system are considered. Design and performance of the first generation 3F to 3F power converter system and field oriented induction moter drive based upon a 3 kVA, 20 kHz parallel resonant HF AC link are described. Low harmonic current at the input and output, unity power factor operation of input, and bidirectional flow capability of the system are shown via both computer and experimental results. The work completed on the construction and testing of the second generation converter and field oriented induction motor drive based upon specifications for a 10 hp squirrel cage dynamometer and a 20 kHz parallel resonant HF AC link is discussed. The induction machine is designed to deliver 10 hp or 7.46 kW when operated as an AC-dynamo with power fed back to the source through the converter. Results presented reveal that the proposed power level requires additional energy storage elements to overcome difficulties with a peak link voltage variation problem that limits reaching to the desired power level. The power level test of the second generation converter after the

  18. Cascading failures in ac electricity grids.

    PubMed

    Rohden, Martin; Jung, Daniel; Tamrakar, Samyak; Kettemann, Stefan

    2016-09-01

    Sudden failure of a single transmission element in a power grid can induce a domino effect of cascading failures, which can lead to the isolation of a large number of consumers or even to the failure of the entire grid. Here we present results of the simulation of cascading failures in power grids, using an alternating current (AC) model. We first apply this model to a regular square grid topology. For a random placement of consumers and generators on the grid, the probability to find more than a certain number of unsupplied consumers decays as a power law and obeys a scaling law with respect to system size. Varying the transmitted power threshold above which a transmission line fails does not seem to change the power-law exponent q≈1.6. Furthermore, we study the influence of the placement of generators and consumers on the number of affected consumers and demonstrate that large clusters of generators and consumers are especially vulnerable to cascading failures. As a real-world topology, we consider the German high-voltage transmission grid. Applying the dynamic AC model and considering a random placement of consumers, we find that the probability to disconnect more than a certain number of consumers depends strongly on the threshold. For large thresholds the decay is clearly exponential, while for small ones the decay is slow, indicating a power-law decay.

  19. Cascading failures in ac electricity grids

    NASA Astrophysics Data System (ADS)

    Rohden, Martin; Jung, Daniel; Tamrakar, Samyak; Kettemann, Stefan

    2016-09-01

    Sudden failure of a single transmission element in a power grid can induce a domino effect of cascading failures, which can lead to the isolation of a large number of consumers or even to the failure of the entire grid. Here we present results of the simulation of cascading failures in power grids, using an alternating current (AC) model. We first apply this model to a regular square grid topology. For a random placement of consumers and generators on the grid, the probability to find more than a certain number of unsupplied consumers decays as a power law and obeys a scaling law with respect to system size. Varying the transmitted power threshold above which a transmission line fails does not seem to change the power-law exponent q ≈1.6 . Furthermore, we study the influence of the placement of generators and consumers on the number of affected consumers and demonstrate that large clusters of generators and consumers are especially vulnerable to cascading failures. As a real-world topology, we consider the German high-voltage transmission grid. Applying the dynamic AC model and considering a random placement of consumers, we find that the probability to disconnect more than a certain number of consumers depends strongly on the threshold. For large thresholds the decay is clearly exponential, while for small ones the decay is slow, indicating a power-law decay.

  20. EFFICIENCY OPTIMIZATIN CONTROL OF AC INDUCTION MOTORS: INITIAL LABORATORY RESULTS

    EPA Science Inventory

    The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. This energy optimizer is complemented by a sensorless speed controller that maintains motor shaft re...

  1. Electrical conductivity and dielectric studies of MnO2 doped V2O5

    NASA Astrophysics Data System (ADS)

    Tan, Foo Khoon; Hassan, Jumiah; Wahab, Zaidan Abd.; Azis, Raba'ah Syahidah

    The investigation on electrical conductivity and dielectric properties of mixed oxide of manganese (Mn) and vanadium (V) was carried out to study the mixed oxides response to different frequencies and different measuring temperatures. The frequency and temperature dependence of AC conductivity, dielectric constant and dielectric loss factor of mixed oxides were studied in the frequency range of 40 Hz-1 MHz and a temperature range of 30-250 °C. Since the mixed oxides are multi phase materials, hence the properties of the pure oxides are also presented in this study to discuss the multi phase behaviour of the mixed oxides. The XRD pattern shows the Mn-V oxide is multiphase and quantitative phase analysis was performed to determine the relative phases. The overall results indicate that with increasing temperature, the AC conductivity, dielectric constant, dielectric loss factor and loss tangent of the Mn-V mixed oxide increases. However, it shows an overlap in the dielectric constant at 225 °C and 250 °C due to the V2O5 phase in the mixed oxide. From the AC activation energy, the mixed oxides underwent conduction mechanism transition from band to hopping in the investigated frequency range. The MnV2O6 has relatively good resistivity, therefore the mixed oxide sintered at 550 °C with the highest composition of MnV2O6 gives the highest dielectric constant of 9845 at 1 kHz, and at 250 °C.

  2. Cross-resistance responses of CrylAc-selected Heliothis virescens (Lepidoptera: Noctuidae) to the Bacillus thuringiensis protein vip3A.

    PubMed

    Jackson, R E; Marcus, M A; Gould, F; Bradley, J R; Van Duyn, J W

    2007-02-01

    One susceptible and three Cry1Ac-resistant strains of tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), were used in laboratory studies to determine the level of cross-resistance between the Bacillus thuringiensis (Berliner) toxins Cry1Ac and Vip3A by using concentration-mortality and leaf tissue experiments. Concentration-mortality data demonstrated that the three Cry1Ac-resistant H. virescens strains, YHD2, KCBhyb, and CxC, were at least 215- to 316-fold resistant to Cry1Ac compared with the susceptible strain, YDK. Results from Vip3A concentration-mortality tests indicated that mortality was similar among all four H. virescens strains. Relative larval growth on Cry1Ac reflected concentration-mortality test results, because YHD2 larval growth was mostly unaffected by the Cry1Ac concentrations tested. Growth ratios for KCBhyb and CXC indicated that they had a more moderate level of resistance to Cry1Ac than did YHD2. Relative larval growth on Vip3A was highly variable at lower concentrations, but it was more consistent on concentrations of Vip3A above 25 microg/ml. Differences in larval growth among strains on Vip3A were not as pronounced as seen in Cry1Ac experiments. Mortality and larval growth also was assessed in leaf tissue bioassays in which YDK, CxC, and KCBhyb neonates were placed onto leaf disks from non-Bt and Bt cotton, Gossypium hirsutum L., for 5 d. Three Bt lines were used in an initial bioassay and consisted of two Vip3A-containing lines, COT203 and COT102, and a Cry1Ac-producing line. Mortality of KCBhyb and CXC was lower than that of YDK larvae in the presence of leaf tissue from the Cry1Ac-producing line. Additionally, increased larval growth and leaf tissue consumption on Cry1Ac-containing leaf disks was observed for KCBhyb and CXC. Mortality and larval weights were similar among strains when larvae were fed leaf tissue of either non-Bt, COT203, or COT102. A subsequent leaf tissue bioassay was conducted that evaluated four

  3. ACS PSF Variations with Temperatures

    NASA Astrophysics Data System (ADS)

    Sahu, Kailash C.; Lallo, Matt; Makidon, Russ

    2007-09-01

    We have used the HST ACS/WFC observations of a Galactic bulge field taken over a continuous interval of 7 days (Prop 9750) to investigate the possible dependence of the ACS focus with the external temperatures. This dataset allows us to investigate possible focus variations over timescales of a few hours to a few days. The engineering data related to the external temperatures for this duration show that the maximum temperature change occurred over the first 1.5 days. Among all the different temperatures recorded, the truss diametric differential and the truss axial temperatures are the only two temperatures which have the same timescale of variation as the PSFwidth variations. The PSF-widths also strongly correlate with these two temperatures during this time interval. We empirically fit the PSF-width variations with these 2 temperature sensor values. This suggests that the focus has a similar dependence, and we recommend that this finding be followed up with the determination of actual focus values to check if the focus values indeed have the same correlation. If so, the temperature data can be useful in estimating the focus values, which can then be used to predict the PSFs to a first order.

  4. Thermal Analysis of AC Contactor Using Thermal Network Finite Difference Analysis Method

    NASA Astrophysics Data System (ADS)

    Niu, Chunping; Chen, Degui; Li, Xingwen; Geng, Yingsan

    To predict the thermal behavior of switchgear quickly, the Thermal Network Finite Difference Analysis method (TNFDA) is adopted in thermal analysis of AC contactor in the paper. The thermal network model is built with nodes, thermal resistors and heat generators, and it is solved using finite difference method (FDM). The main circuit and the control system are connected by thermal resistors network, which solves the problem of multi-sources interaction in the application of TNFDA. The temperature of conducting wires is calculated according to the heat transfer process and the fundamental equations of thermal conduction. It provides a method to solve the problem of boundary conditions in applying the TNFDA. The comparison between the results of TNFDA and measurements shows the feasibility and practicability of the method.

  5. The effect of prism adaptation on the response AC/A ratio.

    PubMed

    Rainey, B B

    2000-05-01

    Vergence adaptation, also known as prism adaptation, is a phenomenon in which a patient's heterophoria changes after prolonged viewing through prism. The effect of prism adaptation on the accommodation-convergence relationship, quantified by the AC/A ratio, is not known. Previous studies of AC/A ratio stability and alterability have used only stimulus AC/A ratio calculations, or have measured accommodative responses to only one or two stimuli. The ideal study of AC/A ratio stability and alterability would measure accommodative responses to several accommodative stimuli, and use these along with vergence responses to calculate response AC/A ratios, rather than stimulus AC/A ratios. In addition, the gradient method should be used to avoid any effect of proximal vergence resulting from changes in target distance. This paper describes a project which investigated the effect of vergence (prism) adaptation on the gradient response AC/A ratio, using accommodative responses measured for five different accommodative stimuli. The response AC/A ratio did not significantly change following a period of adaptation to base-in prism for six of the eight subjects in this study. In addition, the response AC/A ratio did not significantly change following a period of adaptation to base-out prism for six of the eight subjects.

  6. The Single-phase AC Regulator on Base of Bidirectional IGBT Switches

    NASA Astrophysics Data System (ADS)

    Cimanis, Vladimirs; Hramcovs, Vladimirs; Rankis, Ivars

    2010-01-01

    In the work one of the methods for regulation of sinus shape AC voltage for middle-power loads with activeinductive character is observed. Such a regulator keeping output voltage of sinus shape must be fast-reacting and work in closed-loop system. It's shown, that for providing such features Buck and Boost pulse regulators can be applied. The only difference from DC pulse converters is that electronic switches in the system must be with bidirectional conductivity. For this reason an IGBT transistors can be applied with implemented in structure reverse diodes and if such two transistors are connected in series and with contrary conductivity then at activating both one of them will be in on-state. Realization of AC regulators with such switches is described in the work. Results of computer modeling also are given. Output voltage ripples are investigated on subject of their range and efficiency of filtering equipment on LC base. Such regulators can be applied for instance in electrical transport self supply systems.

  7. The ac propulsion system for an electric vehicle, phase 1

    NASA Technical Reports Server (NTRS)

    Geppert, S.

    1981-01-01

    A functional prototype of an electric vehicle ac propulsion system was built consisting of a 18.65 kW rated ac induction traction motor, pulse width modulated (PWM) transistorized inverter, two speed mechanically shifted automatic transmission, and an overall drive/vehicle controller. Design developmental steps, and test results of individual components and the complex system on an instrumented test frame are described. Computer models were developed for the inverter, motor and a representative vehicle. A preliminary reliability model and failure modes effects analysis are given.

  8. AC and Phase Sensing of Nanowires for Biosensing

    PubMed Central

    Crescentini, Marco; Rossi, Michele; Ashburn, Peter; Lombardini, Marta; Sangiorgi, Enrico; Morgan, Hywel; Tartagni, Marco

    2016-01-01

    Silicon nanowires are label-free sensors that allow real-time measurements. They are economical and pave the road for point-of-care applications but require complex readout and skilled personnel. We propose a new model and technique for sensing nanowire sensors using alternating currents (AC) to capture both magnitude and phase information from the sensor. This approach combines the advantages of complex impedance spectroscopy with the noise reduction performances of lock-in techniques. Experimental results show how modifications of the sensors with different surface chemistries lead to the same direct-current (DC) response but can be discerned using the AC approach. PMID:27104577

  9. 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.

  10. Obtaining DC and AC isothermal electrical characteristics for RF MOSFET

    NASA Astrophysics Data System (ADS)

    Sahoo, A. K.; Fregonese, S.; Scheer, P.; Celi, D.; Juge, A.; Zimmer, T.

    2015-04-01

    In this paper we demonstrate a new and simple approach to obtain isothermal electrical characteristics of metal oxide field effect transistor (MOSFET) from conventional non-isothermal measurements. DC and continuous wave (CW) S-parameter measurements are performed at different chuck temperatures (Tchuck). Knowing the thermal resistance (RTH) of the device the variation of DC and AC characteristic due to self-heating can be de-embedded and all the isothermal DC data and AC data above isothermal frequency can be determined. The method is validated by comparing the results with pulsed DC and pulsed RF measurements and found to be in good agreements.

  11. Electrical Conductivity Mechanism in Unconventional Lead Vanadate Glasses

    NASA Astrophysics Data System (ADS)

    Abdel-Wahab, F.; Merazga, A.; Montaser, A. A.

    2017-03-01

    Lead vanadate glasses of the system (V2O5)_{1-x}(PbO)x with x = 0.4, 0.45, 0.5, 0.55, 0.6 have been prepared by the press-quenching technique. The dc (σ (0)) and ac (σ (ω )) electrical conductivities were measured in the temperature range from 150 to 420 K and the frequency range from 102 to 106 Hz. The electrical properties are shown to be sensitive to composition. The experimental results have been analyzed within the framework of different models. The dc conductivity is found to be proportional to Tp with the exponent p ranging from 8.2 to 9.8, suggesting that the transport is determined by a multi-phonon process of weak electron-lattice coupling. The ac conductivity is explained by the percolation path approximation (PPA). In this model, σ (ω ) is closely related to the σ (0) and fitting the experimental data produces a dielectric relaxation time τ in good agreement with the expected value in both magnitude and temperature dependence.

  12. Electrically conductive composite material

    DOEpatents

    Clough, R.L.; Sylwester, A.P.

    1988-06-20

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  13. Electrically conductive composite material

    SciTech Connect

    Clough, R.L.; Sylwester, A.P.

    1989-05-23

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  14. Electrically conductive composite material

    DOEpatents

    Clough, Roger L.; Sylwester, Alan P.

    1989-01-01

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistant pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like.

  15. The diagnostic performance of serum MUC5AC for cholangiocarcinoma

    PubMed Central

    Xuan, Ji; Li, Jing; Zhou, Zhirui; Zhou, Renrong; Xu, Huabing; Wen, Wei

    2016-01-01

    Abstract Specific diagnostic biomarker for cholangiocarcinoma (CCA) has been lacking. This systematic review and meta-analysis was performed aiming to investigate serum MUC5AC's diagnostic performance on CCA. Studies investigating serum MUC5AC's diagnostic value on CCA were retrieved from Pubmed, Embase, and Cochrane Library. The methodology quality of included studies was assessed according to QUADAS-2. Diagnostic 2 × 2 table was extracted from each eligible study, Meta-disc 1.4 was used for statistical analysis, data synthesis was done using a random-effects model. Subgroup analyses were conducted according to region and array method. Six eligible studies were identified, a total of 1213 patients were involved in the meta-analysis. The AUC on SROC was 0.9138, and the Q∗ was 8463. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio (DOR) were 0.69 (95% CI: 0.65–0.73), 0.93 (95% CI: 0.91–0.95), 8.99 (95% CI: 5.65–14.30), 0.33 (95% CI: 0.24–0.46), and 33.98 (95% CI: 20.12–57.40), respectively. Targeting MUC5AC's epitope has a higher pooled sensitivity than targeting MUC5AC protein (0.77 vs 0.63). There was substantial cross-study heterogeneity. Serum MUC5AC might be potentially used as a surrogate marker in the diagnosis of CCA. However, the appropriate array method and the optimum cut-off value are yet to be decided. PMID:27310944

  16. Advanced ac powertrain for electric vehicles

    SciTech Connect

    Slicker, J.M.; Kalns, L.

    1985-01-01

    The design of an ac propulsion system for an electric vehicle includes a three-phase induction motor, transistorized PWM inverter/battery charger, microprocessor-based controller, and two-speed automatic transaxle. This system was built and installed in a Mercury Lynx test bed vehicle as part of a Department of Energy propulsion system development program. An integral part of the inverter is a 4-kw battery charger which utilizes one of the bridge transistors. The overall inverter strategy for this configuration is discussed. The function of the microprocessor-based controller is described. Typical test results of the total vehicle and each of its major components are given, including system efficiencies and test track performance results.

  17. Specific binding of Autographa californica M nucleopolyhedrovirus occlusion-derived virus to midgut cells of Heliothis virescens larvae is mediated by products of pif genes Ac119 and Ac022 but not by Ac115.

    PubMed

    Ohkawa, Taro; Washburn, Jan O; Sitapara, Ronika; Sid, Eric; Volkman, Loy E

    2005-12-01

    Per os infectivity factors PIF1 (Ac119) and PIF2 (Ac022), like P74, are essential for oral infection of lepidopteran larval hosts of Autographa californica M nucleopolyhedrovirus (AcMNPV). Here we show that Ac115 also is a PIF (PIF3) and that, unlike PIF1 and PIF2, it does not mediate specific binding of AcMNPV occlusion-derived virus (ODV) to midgut target cells. We used an improved in vivo fluorescence dequenching assay to compare binding, fusion, and competition among control AcMNPV ODV and the ODVs of AcMNPV PIF1, PIF2, and PIF3 deletion mutants. Our results showed that binding and fusion of PIF1 and PIF2 mutants, but not the PIF3 mutant, were both qualitatively and quantitatively different from those of control ODV. Unlike control and PIF3-deficient ODV, an excess of PIF1- or PIF2-deficient ODV failed to compete effectively with control ODV's binding to specific receptors on midgut epithelial cells. Moreover, the levels of PIF1- and PIF2-deficient ODV binding were depressed threefold compared to control levels. Binding, fusion, and competition by PIF3-deficient ODV, however, were all indistinguishable from those of control ODV. These results implicated PIF1 and PIF2 as ODV envelope attachment proteins that mediate specific binding to primary target cells within the midgut. In contrast, PIF3 mediates another unidentified, but critical, early event during primary infection.

  18. 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.

  19. Performance testing of the AC propulsion ELX electric vehicle

    SciTech Connect

    Kramer, W.E.; MacDowall, R.D.; Burke, A.F.

    1994-06-01

    Performance testing of the AC Propulsion ELX electric vehicle is described. Test data are presented and analyzed. The ELX vehicle is the first of a series of electric vehicles of interest to the California Air Resources Board. The test series is being conducted under a Cooperative Research and Development Agreement (CRADA) between the US Department of energy and the California Air Resources Board. The tests which were conducted showed that the AC Propulsion ELX electric vehicle has exceptional acceleration and range performance. when the vehicle`s battery was fully charged, the vehicle can accelerate from 0 to 96 km/h in about 10 seconds. Energy consumption and range tests using consecutive FUDS and HWFET Driving cycles (the all-electric cycle) indicate that the energy economy of the AC Propulsion ELX electric vehicle with regenerative braking is 97 W{center_dot}h/km, with a range of 153 km (95 miles). Computer simulations performed using the SIMPLEV Program indicate that the vehicle would have a range of 327 km (203 miles) on the all-electric cycle if the lead acid batteries were replaced with NiMH batteries having an energy density of 67 W{center_dot}h/kg. Comparisons of FUDS test data with and without regenerative braking indicated that regenerative braking reduced the energy consumption of the ELX vehicle by approximately 25%.

  20. A general unified approach to modelling switching dc-to-dc converters in discontinuous conduction mode

    NASA Technical Reports Server (NTRS)

    Cuk, S.; Middlebrook, R. D.

    1977-01-01

    A method for modelling switching converters in the discontinuous conduction mode is developed, whose starting point is the unified state-space representation, and whose end result is a complete linear circuit model which correctly represents all essential features, namely, the input, output, and transfer properties (static dc as well as dynamic ac small signal). While the method is generally applicable to any switching converter operating in the discontinuous conduction mode, it is extensively illustrated for the three common power stages (buck, boost, and buck-boost). The results for these converters are then easily tabulated owing to the fixed equivalent circuit topology of their canonical circuit model.

  1. Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection

    PubMed Central

    Mishra, Om P.; Popov, Anatoliy V.; Pietrofesa, Ralph A.; Christofidou-Solomidou, Melpo

    2017-01-01

    Background Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. Methods The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3′-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3′-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton 1H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO− and radiation. Purine base chlorination by ClO− and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Results: Chloride anions (Cl−) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by 1H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO− or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO− generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl•) and dichloro radical anions (Cl2−•)), which were trapped by SDG and its structural analog dopamine. Conclusion We demonstrate that γ-radiation induces the generation of ACS in

  2. Instantaneous characteristics simulation and analysis on three-level brushless AC synchronous generators of aeronautic constant speed and frequency AC power system

    NASA Astrophysics Data System (ADS)

    Ma, Xiaohe; Shen, Songhua

    2006-11-01

    This paper mainly introduces theoretical analysis and experimental results of instantaneous characteristics on a certain three level brushless three-phase AC synchronous generators. The analysis, modeling and simulations with Simplorer software of Ansoft Company are carried out. It establishes three level generator models, gives theoretical relation matrix equation, and simulates some instantaneous characteristics. Design of the system requires reliable simulation tools with comprehensive component libraries capable of dealing with complex system behavior. The simulation results verify that the proposed system model can efficiently simulate the instantaneous characteristics of the real AC generator system. It gives better design experiences and digital methods for aeronautic constant speed and frequency AC power system.

  3. Theoretical analysis on ac susceptibility measurements of superconductor tapes

    NASA Astrophysics Data System (ADS)

    Chen, Du-Xing; Sun, Yue-Ming; Li, Shuo; Fang, Jin

    2017-02-01

    Perpendicular ac susceptibility χ ={χ\\prime}-j{χ\\prime \\prime} of a superconducting long tape defined by magnetic moment and determined inductively by magnetic flux is calculated using Brandt’s technique from a power-law dependence of electric field on sheet current density. The requirements of χ measurements to the experimental setup and procedure are discussed based on the calculation results.

  4. Superconducting phase in UGe2 by AC calorimetry

    NASA Astrophysics Data System (ADS)

    Taufour, Valentin; Aoki, Dai; Knebel, Georg; Flouquet, Jacques

    2012-12-01

    We report on the detection of the superconducting transition Tsc in the superconducting ferromagnet UGe2 by AC calorimetry under pressure. Our results confirm the small value of the specific heat jump. We suggest that this observation is intrinsic in origin and does not arises from a distribution of Tsc due to pressure gradient or sample defects.

  5. Cantilever's behavior in the AC mode of an AFM

    SciTech Connect

    Nunes, V.B.; Zanette, S.I.; Caride, A.O.; Prioli, R.; Rivas, A.M.F

    2003-03-15

    In this paper, a model with a small number of parameters is used to simulate the motion of a cantilever in the AC mode of an atomic force microscope (AFM). The results elucidate the transition dependence-from noncontact to tapping operating mode-on the height of the contamination layer and on the stiffness of the sample.

  6. Modeling and Correcting the Time-Dependent ACS PSF

    NASA Technical Reports Server (NTRS)

    Rhodes, Jason; Massey, Richard; Albert, Justin; Taylor, James E.; Koekemoer, Anton M.; Leauthaud, Alexie

    2006-01-01

    The ability to accurately measure the shapes of faint objects in images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) depends upon detailed knowledge of the Point Spread Function (PSF). We show that thermal fluctuations cause the PSF of the ACS Wide Field Camera (WFC) to vary over time. We describe a modified version of the TinyTim PSF modeling software to create artificial grids of stars across the ACS field of view at a range of telescope focus values. These models closely resemble the stars in real ACS images. Using 10 bright stars in a real image, we have been able to measure HST s apparent focus at the time of the exposure. TinyTim can then be used to model the PSF at any position on the ACS field of view. This obviates the need for images of dense stellar fields at different focus values, or interpolation between the few observed stars. We show that residual differences between our TinyTim models and real data are likely due to the effects of Charge Transfer Efficiency (CTE) degradation. Furthermore, we discuss stochastic noise that is added to the shape of point sources when distortion is removed, and we present MultiDrizzle parameters that are optimal for weak lensing science. Specifically, we find that reducing the MultiDrizzle output pixel scale and choosing a Gaussian kernel significantly stabilizes the resulting PSF after image combination, while still eliminating cosmic rays/bad pixels, and correcting the large geometric distortion in the ACS. We discuss future plans, which include more detailed study of the effects of CTE degradation on object shapes and releasing our TinyTim models to the astronomical community.

  7. An AC electrokinetic method for enhanced detection of DNA nanoparticles.

    PubMed

    Krishnan, Rajaram; Heller, Michael J

    2009-04-01

    In biomedical research and diagnostics it is a challenge to isolate and detect low levels of nanoparticles and nanoscale biomarkers in blood and other biological samples. While highly sensitive epifluorescent microscope systems are available for ultra low level detection, the isolation of the specific entities from large sample volumes is often the bigger limitation. AC electrokinetic techniques like dielectrophoresis (DEP) offer an attractive mechanism for specifically concentrating nanoparticles into microscopic locations. Unfortunately, DEP requires significant sample dilution thus making the technology unsuitable for biological applications. Using a microelectrode array device, special conditions have been found for the separation of hmw-DNA and nanoparticles under high conductance (ionic strength) conditions. At AC frequencies in the 3000-10 000 Hz range, 10 mum microspheres and human T lymphocytes can be isolated into the DEP low field regions, while hmw-DNA and nanoparticles can be concentrated into microscopic high field regions for subsequent detection using an epifluorescent system.

  8. Suppression of RNA Silencing by a Geminivirus Nuclear Protein, AC2, Correlates with Transactivation of Host Genes†

    PubMed Central

    Trinks, Daniela; Rajeswaran, R.; Shivaprasad, P. V.; Akbergenov, Rashid; Oakeley, Edward J.; Veluthambi, K.; Hohn, Thomas; Pooggin, Mikhail M.

    2005-01-01

    Bipartite geminiviruses encode a small protein, AC2, that functions as a transactivator of viral transcription and a suppressor of RNA silencing. A relationship between these two functions had not been investigated before. We characterized both of these functions for AC2 from Mungbean yellow mosaic virus-Vigna (MYMV). When transiently expressed in plant protoplasts, MYMV AC2 strongly transactivated the viral promoter; AC2 was detected in the nucleus, and a split nuclear localization signal (NLS) was mapped. In a model Nicotiana benthamiana plant, in which silencing can be triggered biolistically, AC2 reduced local silencing and prevented its systemic spread. Mutations in the AC2 NLS or Zn finger or deletion of its activator domain abolished both these effects, suggesting that suppression of silencing by AC2 requires transactivation of host suppressor(s). In line with this, in Arabidopsis protoplasts, MYMV AC2 or its homologue from African cassava mosaic geminivirus coactivated >30 components of the plant transcriptome, as detected with Affymetrix ATH1 GeneChips. Several corresponding promoters cloned from Arabidopsis were strongly induced by both AC2 proteins. These results suggest that silencing suppression and transcription activation by AC2 are functionally connected and that some of the AC2-inducible host genes discovered here may code for components of an endogenous network that controls silencing. PMID:15681452

  9. Suppression of RNA silencing by a geminivirus nuclear protein, AC2, correlates with transactivation of host genes.

    PubMed

    Trinks, Daniela; Rajeswaran, R; Shivaprasad, P V; Akbergenov, Rashid; Oakeley, Edward J; Veluthambi, K; Hohn, Thomas; Pooggin, Mikhail M

    2005-02-01

    Bipartite geminiviruses encode a small protein, AC2, that functions as a transactivator of viral transcription and a suppressor of RNA silencing. A relationship between these two functions had not been investigated before. We characterized both of these functions for AC2 from Mungbean yellow mosaic virus-Vigna (MYMV). When transiently expressed in plant protoplasts, MYMV AC2 strongly transactivated the viral promoter; AC2 was detected in the nucleus, and a split nuclear localization signal (NLS) was mapped. In a model Nicotiana benthamiana plant, in which silencing can be triggered biolistically, AC2 reduced local silencing and prevented its systemic spread. Mutations in the AC2 NLS or Zn finger or deletion of its activator domain abolished both these effects, suggesting that suppression of silencing by AC2 requires transactivation of host suppressor(s). In line with this, in Arabidopsis protoplasts, MYMV AC2 or its homologue from African cassava mosaic geminivirus coactivated >30 components of the plant transcriptome, as detected with Affymetrix ATH1 GeneChips. Several corresponding promoters cloned from Arabidopsis were strongly induced by both AC2 proteins. These results suggest that silencing suppression and transcription activation by AC2 are functionally connected and that some of the AC2-inducible host genes discovered here may code for components of an endogenous network that controls silencing.

  10. Results of dynamic stability tests conducted on a .012 scale model modified 089 B shuttle orbiter in the AEDC-VKF tunnel B at a Mach number of 8.0 (LA42)

    NASA Technical Reports Server (NTRS)

    Vaughn, J. E.; Daviet, J. T.

    1975-01-01

    Experimental aerodynamic investigations were conducted on a .012 scale model of a NASA/Langley modified version of the Rockwell 089B Space Shuttle Orbiter. Using the forced oscillation test technique, dynamic stability derivatives were measured in the pitch, yaw and roll planes at a Mach number of 8 over an angle of attack range from -4 deg to 28 deg. Plotted and tabulated results are presented.

  11. Dielectric relaxation in AC powder electroluminescent devices

    NASA Astrophysics Data System (ADS)

    Zhang, Shuai; Su, Haibin; Tan, Chuan Seng; Wong, Terence Kin Shun; Teo, Ronnie Jin Wah

    2017-01-01

    The dielectric properties of AC powder electroluminescent devices were measured and analyzed using complex impedance spectroscopy to determine the relaxation processes occurring within the devices. The relaxation processes identified were ascribed to the electrode polarization caused by ion accumulation at the electrode/resin interfaces, the Maxwell-Wagner-Sillars effects at the (ZnS or BaTiO3) particle/resin interfaces, and the dipolar reorientation of polymer chains in the resin matrix. Each relaxation process was represented by its corresponding equivalent circuit component. Space charge polarization at the electrodes were represented by a Warburg element, a resistor, and a constant phase element. The resin matrix, ZnS/resin and BaTiO3/resin interfaces could each be modeled by a resistor and a capacitor in parallel. The simulated equivalent circuits for three different printed structures showed good fitting with their experimental impedance results.

  12. In situ conductance measurements of copper phthalocyanine thin film growth on sapphire [0001].

    PubMed

    Murdey, Richard; Sato, Naoki

    2011-06-21

    The current flowing through a thin film of copper phthalocyanine vacuum deposited on a single crystal sapphire [0001] surface was measured during film growth from 0 to 93 nm. The results, expressed as conductance vs. nominal film thickness, indicate three distinct film growth regions. Conductive material forms below about 5 nm and again above 35 nm, but in the intermediate thicknesses the film conductance was observed to decrease with increasing film thickness. With the aid of ac-AFM topology images taken ex situ, the conductance results are explained based on the Stranski-Krastanov (2D + 3D) film growth mechanism, in which the formation of a thin wetting layer is followed by the growth of discrete islands that eventually coalesce into an interpenetrating, conductive network.

  13. Residential Proximity to Major Roadways is Associated with Increased Levels of AC133+ Circulating Angiogenic Cells

    PubMed Central

    DeJarnett, Natasha; Yeager, Ray; Conklin, Daniel J.; Lee, Jongmin; O'Toole, Timothy E.; McCracken, James; Abplanalp, Wes; Srivastava, Sanjay; Riggs, Daniel W.; Hamzeh, Ihab; Wagner, Stephen; Chugh, Atul; DeFilippis, Andrew; Ciszewski, Tiffany; Wyatt, Brad; Becher, Carrie; Higdon, Deirdre; Ramos, Kenneth S.; Tollerud, David J.; Myers, John A.; Rai, Shesh N.; Shah, Jasmit; Zafar, Nagma; Krishnasamy, Sathya S.; Prabhu, Sumanth D.; Bhatnagar, Aruni

    2016-01-01

    Objective Previous studies have shown that residential proximity to a roadway is associated with increased cardiovascular disease (CVD) risk. Yet the nature of this association remains unclear, and its impact on individual CVD risk factors has not been assessed. The objective of this study was to determine whether residential proximity to roadways influences systemic inflammation and the levels of circulating angiogenic cells. Approach and Results In a cross-sectional study, CVD risk factors, blood levels of C-reactive protein (CRP), and 15 antigenically-defined circulating angiogenic cell populations were measured in participants (n=316) with moderate to high CVD risk. Attributes of roadways surrounding residential locations were assessed using Geographic Information Systems. Associations between road proximity and cardiovascular indices were analyzed using Generalized Linear Models. Close proximity (<50m) to a major roadway was associated with lower income and higher rates of smoking, but not CRP levels. After adjustment for potential confounders, levels of circulating angiogenic cell in peripheral blood were significantly elevated in people living in close proximity to a major roadway (CD31+/AC133+, AC133+, CD34+/AC133+, and CD34+/45dim/AC133+ cells); and positively associated with road segment distance (CD31+/AC133+, AC133+, and CD34+/AC133+ cells), traffic intensity (CD31+/AC133+ and AC133+ cells), and distance-weighted traffic intensity (CD31+/34+/45+/AC133+ cells). Conclusions Living close to a major roadway is associated with elevated levels of circulating cells positive for the “early” stem marker, AC133+. This may reflect an increased need for vascular repair. Levels of these cells in peripheral blood may be a sensitive index of cardiovascular injury due to residential proximity to roadways. PMID:26293462

  14. AcSDKP Regulates Cell Proliferation through the PI3KCA/Akt Signaling Pathway

    PubMed Central

    Hu, Ping; Li, Bin; Zhang, Wenhua; Li, Yijian; Li, Guang; Jiang, Xinnong; Wdzieczak-Bakala, Joanna; Liu, Jianmiao

    2013-01-01

    The natural tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) is generated from the N-terminus of thymosin-β4 through enzymatic cleavage by prolyl oligopeptidase (POP). AcSDKP regulation of proliferation of different cells is implicated in hematopoiesis and angiogenesis. This tetrapeptide present in almost all cells was recently detected at elevated concentrations in neoplastic diseases. However, previously reported in vitro and in vivo studies indicate that AcSDKP does not contribute to the pathogenesis of cancers. Here we show that exogenous AcSDKP exerts no effect on the proliferation of actively dividing malignant cells. Using S17092, a specific POP inhibitor (POPi), to suppress the biosynthesis of AcSDKP in U87-MG glioblastoma cells characterized by high intracellular levels of this peptide, we found that all tested doses of POPi resulted in an equally effective depletion of AcSDKP, which was not correlated with the dose-dependent decreases in the proliferation rate of treated cells. Interestingly, addition of exogenous AcSDKP markedly reversed the reduction in the proliferation of U87-MG cells treated with the highest dose of POPi, and this effect was associated with activation of the phosphatidylinositol-3 kinase (PI3K)/Akt pathway. However, extracellular-regulated protein kinase (ERK) activation was unaltered by S17092 and AcSDKP co-treatment. Knockdown of individual PI3K catalytic subunits revealed that p110α and p110β contributed differently to AcSDKP regulation of U87-MG cell proliferation. Disruption of p110α expression by small interfering RNA (siRNA) abrogated AcSDKP-stimulated Akt phosphorylation, whereas knockdown of p110β expression exhibited no such effect. Our findings indicate for the first time that the PI3KCA/Akt pathway mediates AcSDKP regulation of cell proliferation and suggest a role for this ubiquitous intracellular peptide in cell survival. PMID:24244481

  15. Experimental Investigation of Electrical Conductivity and Permittivity of SC-TiO 2 -EG Nanofluids.

    PubMed

    Fal, Jacek; Barylyak, Adriana; Besaha, Khrystyna; Bobitski, Yaroslav V; Cholewa, Marian; Zawlik, Izabela; Szmuc, Kamil; Cebulski, Józef; Żyła, Gaweł

    2016-12-01

    The paper presents experimental studies of dielectric properties of nanofluids based on ethylene glycol and SC-TiO2 nanoparticles with average size of 15-40 nm with various mass concentrations. The dielectric permittivity both real part and imaginary part as a function of temperature and frequency were measured. Also, dependence ac conductivity on frequency, temperature, and mass concentration were investigated. Based on the curves of ac conductivity, dc conductivity was calculated, and 400 % enhancement in dc conductivity was exposed.

  16. Experimental Investigation of Electrical Conductivity and Permittivity of SC-TiO 2 -EG Nanofluids

    NASA Astrophysics Data System (ADS)

    Fal, Jacek; Barylyak, Adriana; Besaha, Khrystyna; Bobitski, Yaroslav V.; Cholewa, Marian; Zawlik, Izabela; Szmuc, Kamil; Cebulski, Józef; żyła, Gaweł

    2016-08-01

    The paper presents experimental studies of dielectric properties of nanofluids based on ethylene glycol and SC-TiO2 nanoparticles with average size of 15-40 nm with various mass concentrations. The dielectric permittivity both real part and imaginary part as a function of temperature and frequency were measured. Also, dependence ac conductivity on frequency, temperature, and mass concentration were investigated. Based on the curves of ac conductivity, dc conductivity was calculated, and 400 % enhancement in dc conductivity was exposed.

  17. Resveratrol inhibits mucus overproduction and MUC5AC expression in a murine model of asthma.

    PubMed

    Ni, Zhen-Hua; Tang, Ji-Hong; Chen, Guo; Lai, Yi-Min; Chen, Qing-Ge; Li, Zao; Yang, Wei; Luo, Xu-Min; Wang, Xiong-Biao

    2016-01-01

    Previous in vitro studies have demonstrated that resveratrol is able to significantly inhibit the upregulation of mucin 5AC (MUC5AC), a major component of mucus; thus indicating that resveratrol may have potential in regulating mucus overproduction. However, there have been few studies regarding the resveratrol‑mediated prevention of MUC5AC overproduction in vivo, and the mechanisms by which resveratrol regulates MUC5AC expression have yet to be elucidated. In the present study, an ovalbumin (OVA)‑challenged murine model of asthma was used to assess the effects of resveratrol treatment on mucus production in vivo. The results demonstrated that resveratrol significantly inhibited OVA‑induced airway inflammation and mucus production. In addition, the mRNA and protein expression levels of MUC5AC were increased in the OVA‑challenged mice, whereas treatment with resveratrol significantly inhibited this effect. The expression levels of murine calcium‑activated chloride channel (mCLCA)3, an important key mediator of MUC5AC production, were also reduced following resveratrol treatment. Furthermore, in vitro studies demonstrated that resveratrol significantly inhibited human (h)CLCA1 and MUC5AC expression in a dose‑dependent manner. These results indicated that resveratrol was effective in preventing mucus overproduction and MUC5AC expression in vivo, and its underlying mechanism may be associated with regulation of the mCLCA3/hCLCA1 signaling pathway.

  18. Calibration-free electrical conductivity measurements for highly conductive slags

    SciTech Connect

    MACDONALD,CHRISTOPHER J.; GAO,HUANG; PAL,UDAY B.; VAN DEN AVYLE,JAMES A.; MELGAARD,DAVID K.

    2000-05-01

    This research involves the measurement of the electrical conductivity (K) for the ESR (electroslag remelting) slag (60 wt.% CaF{sub 2} - 20 wt.% CaO - 20 wt.% Al{sub 2}O{sub 3}) used in the decontamination of radioactive stainless steel. The electrical conductivity is measured with an improved high-accuracy-height-differential technique that requires no calibration. This method consists of making continuous AC impedance measurements over several successive depth increments of the coaxial cylindrical electrodes in the ESR slag. The electrical conductivity is then calculated from the slope of the plot of inverse impedance versus the depth of the electrodes in the slag. The improvements on the existing technique include an increased electrochemical cell geometry and the capability of measuring high precision depth increments and the associated impedances. These improvements allow this technique to be used for measuring the electrical conductivity of highly conductive slags such as the ESR slag. The volatilization rate and the volatile species of the ESR slag measured through thermogravimetric (TG) and mass spectroscopy analysis, respectively, reveal that the ESR slag composition essentially remains the same throughout the electrical conductivity experiments.

  19. Quality-assurance results for field pH and specific-conductance measurements, and for laboratory analysis, National Atmospheric Deposition Program and National Trends Network; January 1980-September 1984

    USGS Publications Warehouse

    Schroder, L.J.; Brooks, M.H.; Malo, B.A.; Willoughby, T.C.

    1986-01-01

    Five intersite comparison studies for the field determination of pH and specific conductance, using simulated-precipitation samples, were conducted by the U.S.G.S. for the National Atmospheric Deposition Program and National Trends Network. These comparisons were performed to estimate the precision of pH and specific conductance determinations made by sampling-site operators. Simulated-precipitation samples were prepared from nitric acid and deionized water. The estimated standard deviation for site-operator determination of pH was 0.25 for pH values ranging from 3.79 to 4.64; the estimated standard deviation for specific conductance was 4.6 microsiemens/cm at 25 C for specific-conductance values ranging from 10.4 to 59.0 microsiemens/cm at 25 C. Performance-audit samples with known analyte concentrations were prepared by the U.S.G.S.and distributed to the National Atmospheric Deposition Program 's Central Analytical Laboratory. The differences between the National Atmospheric Deposition Program and national Trends Network-reported analyte concentrations and known analyte concentrations were calculated, and the bias and precision were determined. For 1983, concentrations of calcium, magnesium, sodium, and chloride were biased at the 99% confidence limit; concentrations of potassium and sulfate were unbiased at the 99% confidence limit. Four analytical laboratories routinely analyzing precipitation were evaluated in their analysis of identical natural- and simulated precipitation samples. Analyte bias for each laboratory was examined using analysis of variance coupled with Duncan 's multiple-range test on data produced by these laboratories, from the analysis of identical simulated-precipitation samples. Analyte precision for each laboratory has been estimated by calculating a pooled variance for each analyte. Interlaboratory comparability results may be used to normalize natural-precipitation chemistry data obtained from two or more of these laboratories. (Author

  20. AC-coupled front-end for biopotential measurements.

    PubMed

    Spinelli, Enrique Mario; Pallàs-Areny, Ramon; Mayosky, Miguel Angel

    2003-03-01

    AC coupling is essential in biopotential measurements. Electrode offset potentials can be several orders of magnitude larger than the amplitudes of the biological signals of interest, thus limiting the admissible gain of a dc-coupled front end to prevent amplifier saturation. A high-gain input stage needs ac input coupling. This can be achieved by series capacitors, but in order to provide a bias path, grounded resistors are usually included, which degrade the common mode rejection ratio (CMRR). This paper proposes a novel balanced input ac-coupling network that provides a bias path without any connection to ground, thus resulting in a high CMRR. The circuit being passive, it does not limit the differential dc input voltage. Furthermore, differential signals are ac coupled, whereas common-mode voltages are dc coupled, thus allowing the closed-loop control of the dc common mode voltage by means of a driven-right-leg circuit. This makes the circuit compatible with common-mode dc shifting strategies intended for single-supply biopotential amplifiers. The proposed circuit allows the implementation of high-gain biopotential amplifiers with a reduced number of parts, thus resulting in low power consumption. An electrocardiogram amplifier built according to the proposed design achieves a CMRR of 123 dB at 50 Hz.

  1. Established and potential physiological roles of bicarbonate-sensing soluble adenylyl cyclase (sAC) in aquatic animals

    PubMed Central

    Tresguerres, Martin; Barott, Katie L.; Barron, Megan E.; Roa, Jinae N.

    2014-01-01

    Soluble adenylyl cyclase (sAC) is a recently recognized source of the signaling molecule cyclic AMP (cAMP) that is genetically and biochemically distinct from the classic G-protein-regulated transmembrane adenylyl cyclases (tmACs). Mammalian sAC is distributed throughout the cytoplasm and it may be present in the nucleus and inside mitochondria. sAC activity is directly stimulated by HCO3−, and sAC has been confirmed to be a HCO3− sensor in a variety of mammalian cell types. In addition, sAC can functionally associate with carbonic anhydrases to act as a de facto sensor of pH and CO2. The two catalytic domains of sAC are related to HCO3−-regulated adenylyl cyclases from cyanobacteria, suggesting the cAMP pathway is an evolutionarily conserved mechanism for sensing CO2 levels and/or acid/base conditions. Reports of sAC in aquatic animals are still limited but are rapidly accumulating. In shark gills, sAC senses blood alkalosis and triggers compensatory H+ absorption. In the intestine of bony fishes, sAC modulates NaCl and water absorption. And in sea urchin sperm, sAC may participate in the initiation of flagellar movement and in the acrosome reaction. Bioinformatics and RT-PCR results reveal that sAC orthologs are present in most animal phyla. This review summarizes the current knowledge on the physiological roles of sAC in aquatic animals and suggests additional functions in which sAC may be involved. PMID:24574382

  2. Established and potential physiological roles of bicarbonate-sensing soluble adenylyl cyclase (sAC) in aquatic animals.

    PubMed

    Tresguerres, Martin; Barott, Katie L; Barron, Megan E; Roa, Jinae N

    2014-03-01

    Soluble adenylyl cyclase (sAC) is a recently recognized source of the signaling molecule cyclic AMP (cAMP) that is genetically and biochemically distinct from the classic G-protein-regulated transmembrane adenylyl cyclases (tmACs). Mammalian sAC is distributed throughout the cytoplasm and it may be present in the nucleus and inside mitochondria. sAC activity is directly stimulated by HCO3(-), and sAC has been confirmed to be a HCO3(-) sensor in a variety of mammalian cell types. In addition, sAC can functionally associate with carbonic anhydrases to act as a de facto sensor of pH and CO2. The two catalytic domains of sAC are related to HCO3(-)-regulated adenylyl cyclases from cyanobacteria, suggesting the cAMP pathway is an evolutionarily conserved mechanism for sensing CO2 levels and/or acid/base conditions. Reports of sAC in aquatic animals are still limited but are rapidly accumulating. In shark gills, sAC senses blood alkalosis and triggers compensatory H(+) absorption. In the intestine of bony fishes, sAC modulates NaCl and water absorption. And in sea urchin sperm, sAC may participate in the initiation of flagellar movement and in the acrosome reaction. Bioinformatics and RT-PCR results reveal that sAC orthologs are present in most animal phyla. This review summarizes the current knowledge on the physiological roles of sAC in aquatic animals and suggests additional functions in which sAC may be involved.

  3. Evaluation of the in vivo genotoxicity of Allura Red AC (Food Red No. 40).

    PubMed

    Honma, Masamitsu

    2015-10-01

    Allura Red AC (Food Red No. 40) is a red azo dye that is used for food coloring in beverage and confectionary products. However, its genotoxic properties remain controversial. To clarify the in vivo genotoxicity, we treated mice with Allura Red AC and investigated the induction of DNA damage (liver, glandular stomach), clastogenicity/anuegenicity (bone marrow), and mutagenicity (liver, glandular stomach) using Comet assays, micronucleus tests, and transgenic gene mutation assays, respectively. All studies were conducted in accordance with the Organization for Economic Co-operation and Development (OECD) guideline. Although Allura Red AC was administered up to the maximum doses recommended by the OECD guideline, no genotoxic effect was observed in any of the genotoxic endpoints. These data clearly show no evidence of in vivo genotoxic potential of Allura Red AC administered up to the maximum doses in mice.

  4. Conductive Critical Thinking

    ERIC Educational Resources Information Center

    Paetkau, Mark

    2007-01-01

    One of my goals as an instructor is to teach students critical thinking skills. This paper presents an example of a student-led discussion of heat conduction at the first-year level. Heat loss from a human head is calculated using conduction and radiation models. The results of these plausible (but wrong) models of heat transfer contradict what…

  5. Alternating current electrokinetic separation and detection of DNA nanoparticles in high-conductance solutions.

    PubMed

    Krishnan, Rajaram; Sullivan, Benjamin D; Mifflin, Robert L; Esener, Sadik C; Heller, Michael J

    2008-05-01

    In biomedical research and diagnostics, it is a significant challenge to directly isolate and identify rare cells and potential biomarkers in blood, plasma and other clinical samples. Additionally, the advent of bionanotechnology is leading to numerous drug delivery approaches that involve encapsulation of drugs and imaging agents within nanoparticles, which now will also have to be identified and separated from blood and plasma. Alternating current (AC) electrokinetic techniques such as dielectrophoresis (DEP) offer a particularly attractive mechanism for the separation of cells and nanoparticles. Unfortunately, present DEP techniques require the dilution of blood/plasma, thus making the technology less suitable for clinical sample preparation. Using array devices with microelectrodes over-coated with porous hydrogel layers, AC electric field conditions have been found which allow the separation of DNA nanoparticles to be achieved under high-conductance (ionic strength) conditions. At AC frequencies in the 3000 Hz to 10,000 Hz range and 10 volts peak-to-peak, the separation of 10-microm polystyrene particles into low field regions, and 60-nm DNA-derivatized nanoparticles and 200-nm nanoparticles into high-field regions was carried out in 149 mM 1xPBS buffer (1.68 S/m). These results may allow AC electrokinetic systems to be developed that can be used with clinically relevant samples under physiological conditions.

  6. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    NASA Astrophysics Data System (ADS)

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat

    2015-04-01

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (Te) and electron number density (ne) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10-17 - 10-18 m-3 where the electron temperature is between 1.00-2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

  7. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    SciTech Connect

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat

    2015-04-24

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (T{sub e}) and electron number density (n{sub e}) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10{sup −17} − 10{sup −18} m{sup −3} where the electron temperature is between 1.00−2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

  8. ACS Internal CTE Monitor and Short Darks

    NASA Astrophysics Data System (ADS)

    Ogaz, Sara

    2012-10-01

    This is a continuation of Program 12386 and is to be executed once a cycle for internal CTE and short darks, respectively.INTERNAL CTE MONITOR:The charge transfer efficiency {CTE} of the ACS CCD detectors will decline as damage due to on-orbit radiation exposure accumulates. This degradation will be monitored once a cycle to determine the useful lifetime of the CCDs. All the data for this program is acquired using internal targets {lamps} only, so all of the exposures should be taken during Earth occultation time {but not during SAA passages}. This program emulates the ACS pre-flight ground calibration and post-launch SMOV testing {program 8948}, so that results from each epoch can be directly compared. Extended Pixel Edge Response {EPER} data will be obtained over a range of signal levels for the Wide Field Channel {WFC}. The signal levels are 125, 500, 1620, 5000, 10000, and 60000 electrons at gain 2.Since Cycle 18, this monitoring program was reduced {compared to 11881} considering that there is also an external CTE monitoring program.SHORT DARKS:To improve the pixel-based CTE model at signals below 10 DN, short dark frames are needed to obtain a statistically useful sample of clean, warm pixel trails. This program obtains a set of dark frames for each of the following exposure times: 66 s {60 s for some subarrays} and 339 s. These short darks and the 1040 s darks obtained from the CCD Daily Monitor will sample warm and hot pixels over logarithmically increasing brightness. Subarray short darks were newly added in Cycle 19 to study CTE tails in different subarray readout modes.

  9. ACS Internal CTE Monitor and Short Darks

    NASA Astrophysics Data System (ADS)

    Ogaz, Sara

    2013-10-01

    This is a continuation of Program 13156 and is to be executed once a cycle for internal CTE and short darks, respectively.INTERNAL CTE MONITOR:The charge transfer efficiency {CTE} of the ACS CCD detectors will decline as damage due to on-orbit radiation exposure accumulates. This degradation will be monitored once a cycle to determine the useful lifetime of the CCDs. All the data for this program is acquired using internal targets {lamps} only, so all of the exposures should be taken during Earth occultation time {but not during SAA passages}. This program emulates the ACS pre-flight ground calibration and post-launch SMOV testing {program 8948}, so that results from each epoch can be directly compared. Extended Pixel Edge Response {EPER} data will be obtained over a range of signal levels for the Wide Field Channel {WFC}. The signal levels are 125, 500, 1620, 5000, 10000, and 60000 electrons at gain 2.Since Cycle 18, this monitoring program was reduced {compared to 11881} considering that there is also an external CTE monitoring program.SHORT DARKS:To improve the pixel-based CTE model at signals below 10 DN, short dark frames are needed to obtain a statistically useful sample of clean, warm pixel trails. This program obtains a set of dark frames for each of the following exposure times: 66 s {60 s for some subarrays} and 339 s. These short darks and the 1040 s darks obtained from the CCD Daily Monitor will sample warm and hot pixels over logarithmically increasing brightness. Subarray short darks were added in Cycle 19 to study CTE tails in different subarray readout modes.

  10. ACS Internal CTE Monitor and Short Darks

    NASA Astrophysics Data System (ADS)

    Lian Lim, Pey

    2010-09-01

    INTERNAL CTE MONITOR:The charge transfer efficiency {CTE} of the ACS CCD detectors will decline as damage due to on-orbit radiation exposure accumulates. This degradation will be monitored once a cycle to determine the useful lifetime of the CCDs. All the data for this program is acquired using internal targets {lamps} only, so all of the exposures should be taken during Earth occultation time {but not during SAA passages}. This program emulates the ACS pre-flight ground calibration and post-launch SMOV testing {program 8948}, so that results from each epoch can be directly compared. Extended Pixel Edge Response {EPER} data will be obtained over a range of signal levels for the Wide Field Channel {WFC}. The signal levels are 125, 500, 1620, 5000, 10000, and 60000 electrons at gain 2.In Cycle 18, this monitoring program has been reduced {compared to 11881} considering that there is also an external CTE monitoring program. High Resolution Camera {HRC} is not available for observations. First Pixel Response {FPR} exposures are removed because they only provide serial CTE for WFC, which is not that useful. Pseudo-bias exposures are removed because they are not used. Signal levels 300, 700, 1000, 30000, and 45000.electrons are removed to reduce total orbits. Number of exposures per setting are reduced to 1 only. Amps BC are removed since amp dependence is not an issue for EPER.SHORT DARKS:To improve the pixel-based CTE model at signals below 10 DN, short dark frames are needed to obtain a statistically useful sample of clean, warm pixel trails. This program obtains 9 dark frames for each of the following exposure times: 33 s, 100 s, and 339 s. These short darks and the 1000 s darks obtained from the CCD Daily Monitor will sample warm and hot pixels over logarithmically increasing brightness.This is a continuation of Program 12327 and is to be executed once a cycle.

  11. ACS Internal CTE Monitor and Short Darks

    NASA Astrophysics Data System (ADS)

    Lian Lim, Pey

    2011-10-01

    This is a continuation of Program 12386 and is to be executed once a cycle for internal CTE and short darks, respectively.INTERNAL CTE MONITOR:The charge transfer efficiency {CTE} of the ACS CCD detectors will decline as damage due to on-orbit radiation exposure accumulates. This degradation will be monitored once a cycle to determine the useful lifetime of the CCDs. All the data for this program is acquired using internal targets {lamps} only, so all of the exposures should be taken during Earth occultation time {but not during SAA passages}. This program emulates the ACS pre-flight ground calibration and post-launch SMOV testing {program 8948}, so that results from each epoch can be directly compared. Extended Pixel Edge Response {EPER} data will be obtained over a range of signal levels for the Wide Field Channel {WFC}. The signal levels are 125, 500, 1620, 5000, 10000, and 60000 electrons at gain 2.Since Cycle 18, this monitoring program was reduced {compared to 11881} considering that there is also an external CTE monitoring program.SHORT DARKS:To improve the pixel-based CTE model at signals below 10 DN, short dark frames are needed to obtain a statistically useful sample of clean, warm pixel trails. This program obtains a set of dark frames for each of the following exposure times: 66 s {60 s for some subarrays} and 339 s. These short darks and the 1040 s darks obtained from the CCD Daily Monitor will sample warm and hot pixels over logarithmically increasing brightness. Subarray short darks are newly added in Cycle 19 to study CTE tails in different subarray readout modes.

  12. The cultivation of Bt corn producing Cry1Ac toxins does not adversely affect non-target arthropods.

    PubMed

    Guo, Yanyan; Feng, Yanjie; Ge, Yang; Tetreau, Guillaume; Chen, Xiaowen; Dong, Xuehui; Shi, Wangpeng

    2014-01-01

    Transgenic corn producing Cry1Ac toxins from Bacillus thuringiensis (Bt) provides effective control of Asian corn borer, Ostrinia furnacalis (Guenée), and thus reduces insecticide applications. However, whether Bt corn exerts undesirable effects on non-target arthropods (NTAs) is still controversial. We conducted a 2-yr study in Shangzhuang Agricultural Experiment Station to assess the potential impact of Bt corn on field population density, biodiversity, community composition and structure of NTAs. On each sampling date, the total abundance, Shannon's diversity index, Pielou's evenness index and Simpson's diversity index were not significantly affected by Bt corn as compared to non-Bt corn. The "sampling dates" had a significant effect on these indices, but no clear tendencies related to "Bt corn" or "sampling dates X corn variety" interaction were recorded. Principal response curve analysis of variance indicated that Bt corn did not alter the distribution of NTAs communities. Bray-Curtis dissimilarity and distance analysis showed that Cry1Ac toxin exposure did not increase community dissimilarities between Bt and non-Bt corn plots and that the evolution of non-target arthropod community was similar on the two corn varieties. The cultivation of Bt corn failed to show any detrimental evidence on the density of non-target herbivores, predators and parasitoids. The composition of herbivores, predators and parasitoids was identical in Bt and non-Bt corn plots. Taken together, results from the present work support that Bt corn producing Cry1Ac toxins does not adversely affect NTAs.

  13. 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.

  14. Phylogenetic Ecology of the Freshwater Actinobacteria acI Lineage▿ †

    PubMed Central

    Newton, Ryan J.; Jones, Stuart E.; Helmus, Matthew R.; McMahon, Katherine D.

    2007-01-01

    The acI lineage of freshwater Actinobacteria is a cosmopolitan and often numerically dominant member of lake bacterial communities. We conducted a survey of acI 16S rRNA genes and 16S-23S rRNA internal transcribed spacer regions from 18 Wisconsin lakes and used standard nonphylogenetic and phylogenetic statistical approaches to investigate the factors that determine acI community composition at the local scale (within lakes) and at the regional scale (across lakes). Phylogenetic reconstruction of 434 acI 16S rRNA genes revealed a well-defined and highly resolved phylogeny. Eleven previously unrecognized monophyletic clades, each with ≥97.9% within-clade 16S rRNA gene sequence identity, were identified. Clade community similarity positively correlated with lake environmental similarity but not with geographic distance, implying that the lakes represent a single biotic region containing environmental filters for communities that have similar compositions. Phylogenetically disparate clades within the acI lineage were most abundant at the regional scale, and local communities were comprised of more closely related clades. Lake pH was a strong predictor of the community composition, but only when lakes with a pH below 6 were included in the data set. In the remaining lakes (pH above 6) biogeographic patterns in the landscape were instead a predictor of the observed acI community structure. The nonrandom distribution of the newly defined acI clades suggests potential ecophysiological differences between the clades, with acI clades AI, BII, and BIII preferring acidic lakes and acI clades AII, AVI, and BI preferring more alkaline lakes. PMID:17827330

  15. Large Scale Accelerator Production of 225Ac: Effective Cross sections for 78-192 MeV Protons Incident on 232Th Targets

    DOE PAGES

    Griswold, Justin R; Medvedev, Dmitri G.; Engle, Jonathan W.; ...

    2016-09-28

    Actinium-225 and 213Bi have been used successfully in targeted alpha therapy (TAT) in preclinical and clinical research. This paper is a continuation of research activities aiming to expand the availability of 225Ac. The high energy proton spallation reaction on natural thorium metal target has been utilized to produce millicurie quantities of 225Ac. The results of sixteen irradiation experiments of Th metal at beam energies between 78 and 200 MeV are summarized in this work. Irradiations have been conducted at Brookhaven National Laboratory (BNL) and Los Alamos National Laboratory (LANL), while target dissolution and processing was carried out at Oak Ridgemore » National Laboratory (ORNL). Excitation functions for actinium and thorium isotopes as well as for some of the fission products are presented. The cross sections for production of 225Ac range from 3.6 to 16.7 mb in the incident proton energy range of 78 to 192 MeV. Based on these data, production of Curie quantities of 225Ac is possible by irradiating a 5.0 g cm-2232Th target for 10 days in either BNL or LANL proton irradiation facilities.« less

  16. Large scale accelerator production of (225)Ac: Effective cross sections for 78-192MeV protons incident on (232)Th targets.

    PubMed

    Griswold, J R; Medvedev, D G; Engle, J W; Copping, R; Fitzsimmons, J M; Radchenko, V; Cooley, J C; Fassbender, M E; Denton, D L; Murphy, K E; Owens, A C; Birnbaum, E R; John, K D; Nortier, F M; Stracener, D W; Heilbronn, L H; Mausner, L F; Mirzadeh, S

    2016-12-01

    Actinium-225 and (213)Bi have been used successfully in targeted alpha therapy (TAT) in preclinical and clinical research. This paper is a continuation of research activities aiming to expand the availability of (225)Ac. The high-energy proton spallation reaction on natural thorium metal targets has been utilized to produce millicurie quantities of (225)Ac. The results of sixteen irradiation experiments of thorium metal at beam energies between 78 and 192MeV are summarized in this work. Irradiations have been conducted at Brookhaven National Laboratory (BNL) and Los Alamos National Laboratory (LANL), while target dissolution and processing was carried out at Oak Ridge National Laboratory (ORNL). Excitation functions for actinium and thorium isotopes, as well as for some of the fission products, are presented. The cross sections for production of (225)Ac range from 3.6 to 16.7mb in the incident proton energy range of 78-192MeV. Based on these data, production of curie quantities of (225)Ac is possible by irradiating a 5.0gcm(-2 232)Th target for 10 days in either BNL or LANL proton irradiation facilities.

  17. Substituted Phthalimide AC94377 Is a Selective Agonist of the Gibberellin Receptor GID11[OPEN

    PubMed Central

    Otani, Masato; Shimotakahara, Hiroaki; Yoon, Jung-Min; Park, Seung-Hyun; Miyaji, Tomoko; Nakano, Takeshi; Nakamura, Hidemitsu; Nakajima, Masatoshi

    2017-01-01

    Gibberellin (GA) is a major plant hormone that regulates plant growth and development and is widely used as a plant growth regulator in agricultural production. There is an increasing demand for function-limited GA mimics due to the limitations on the agronomical application of GA to crops, including GA’s high cost of producing and its leading to the crops’ lodging. AC94377, a substituted phthalimide, is a chemical that mimics the growth-regulating activity of GAs in various plants, despite its structural difference. Although AC94377 is widely studied in many weeds and crops, its mode of action as a GA mimic is largely unknown. In this study, we confirmed that AC94377 displays GA-like activities in Arabidopsis (Arabidopsis thaliana) and demonstrated that AC94377 binds to the Arabidopsis GIBBERELLIN INSENSITIVE DWARF1 (GID1) receptor (AtGID1), forms the AtGID1-AC94377-DELLA complex, and induces the degradation of DELLA protein. Our results also indicated that AC94377 is selective for a specific subtype among three AtGID1s and that the selectivity of AC94377 is attributable to a single residue at the entrance to the hydrophobic pocket of GID1. We conclude that AC94377 is a GID1 agonist with selectivity for a specific subtype of GID1, which could be further developed and used as a function-limited regulator of plant growth in both basic study and agriculture. PMID:27899534

  18. Circulation autoantibody against Lamin A/C in patients with Sjögren's syndrome

    PubMed Central

    Chen, Peng; Yang, Chunhe; Gan, Xianfeng; Hussain, Muhammad; Xun, Yiping; Tian, Yaping; Du, Hongwu

    2016-01-01

    Lamin A/C proteins are major components of nuclear laminae and were encoded by the LMNA gene. Recent studies have found that in addition to provides nuclear-membrane strength; it also regulates the gene expression. Lamin A/C has been confirmed as an autoantigen in RA, SLE and vasculitis. Anti-Lamin A/C antibodies also have been found by indirect immunofluorescence method. In this study, we used various research methods to confirm Lamin A/C is an autoantigen in Han Chinese patients with confirmed Sjögren's syndrome (SS). To further investigate the relationship between the autoimmune disease antigens, we compared the amino acid sequence of Lamin A/C epitope and several common antigens' antigenic determinant. As a result, we found that Lamin A/C has similar epitopes with U1RNP. It means that the potential relationship exist between Lamin A/C and U1RNP. Clinical data we collected also showed that anti-Lamin A/C and anti-U1RNP antibodies always appear in same serum sample. Therefore, we speculated that cross-reaction may take place between antigen and potential antigen, which have similar epitope. Then, by epitope spreading, the potential antigen can be a new autoantigen. Our study provided a new thinking for further research about the relationship between autoantigens and their development mechanism in autoimmune diseases. PMID:27835913

  19. Thrust distribution for attitude control in a variable thrust propulsion system with four ACS nozzles

    NASA Astrophysics Data System (ADS)

    Lim, Yeerang; Lee, Wonsuk; Bang, Hyochoong; Lee, Hosung

    2017-04-01

    A thrust distribution approach is proposed in this paper for a variable thrust solid propulsion system with an attitude control system (ACS) that uses a reduced number of nozzles for a three-axis attitude maneuver. Although a conventional variable thrust solid propulsion system needs six ACS nozzles, this paper proposes a thrust system with four ACS nozzles to reduce the complexity and mass of the system. The performance of the new system was analyzed with numerical simulations, and the results show that the performance of the system with four ACS nozzles was similar to the original system while the mass of the whole system was simultaneously reduced. Moreover, a feasibility analysis was performed to determine whether a thrust system with three ACS nozzles is possible.

  20. Selective and high affinity labeling of neuronal and recombinant nociceptin receptors with the hexapeptide radioprobe [(3)H]Ac-RYYRIK-ol.

    PubMed

    Bojnik, Engin; Farkas, Judit; Magyar, Anna; Tömböly, Csaba; Güçlü, Umit; Gündüz, Ozge; Borsodi, Anna; Corbani, Maïthe; Benyhe, Sándor

    2009-12-01

    The synthetic hexapeptide Ac-Arg-Tyr-Tyr-Arg-Ile-Lys-ol (Ac-RYYRIK-ol) represents a highly potent and selective partial agonist ligand for the nociceptin/orphanin FQ (N/OFQ) peptide receptor (nociceptin receptor, NOPr). Ac-RYYRIK-ol has been labeled with tritium yielding [(3)H]Ac-RYYRIK-ol with exceptionally high specific radioactivity of 94Ci/mmol. The radioprobe is chemically stable even at 24 degrees C in ethanol solution for at least 4 days. No significant decomposition of the [(3)H]ligand occurred under the condition of the binding experiments indicating a fine enzymatic stability of the peptide. Radioreceptor binding studies were conducted using native neuronal NOPr preparation of rat brain membrane fractions and recombinant human nociceptin receptor ((h)NOPr) preparations from cultured Chinese Hamster Ovary (CHO) cells stably expressing (h)NOPr. Specific binding of the compound was reversible, saturable and of high affinity. No cross-reaction with the opioid receptors was observed suggesting superior NOPr selectivity of the ligand. Monophasic isotherm curves obtained in radioligand binding saturation and homologous displacement experiments indicated the presence of single binding sites in both preparations. Average densities of the [(3)H]Ac-RYYRIK-ol recognition sites were 237 and 749fmol/mg protein in rat brain and transfected cells, respectively. Equilibrium affinity values (K(d)s) were determined by three independent way providing identical results. In rat brain membranes K(d)s of 0.3-1.3nM were found depending upon the assay type. In homologous competition studies performed on (h)NOP-CHO cell membranes almost the same binding affinities were measured for Ac-RYYRIK-ol either with [(3)H]Ac-RYYRIK-ol (K(i) 2.8nM) or with [(3)H](Leu(14))nociceptin (2.3nM). A number of NOPr and opioid ligands were screened in heterologous displacement experiments and displayed a rank order of affinity profile being consistent with fairly good NOPr selectivity of the sites

  1. Combined AC electroosmosis and dielectrophoresis for controlled rotation of microparticles

    PubMed Central

    Walid Rezanoor, Md.; Dutta, Prashanta

    2016-01-01

    Electrorotation is widely used for characterization of biological cells and materials using a rotating electric field. Generally, multiphase AC electric fields and quadrupolar electrode configuration are needed to create a rotating electric field for electrorotation. In this study, we demonstrate a simple method to rotate dielectrophoretically trapped microparticles using a stationary AC electric field. Coplanar interdigitated electrodes are used to create a linearly polarized nonuniform AC electric field. This nonuniform electric field is employed for dielectrophoretic trapping of microparticles as well as for generating electroosmotic flow in the vicinity of the electrodes resulting in rotation of microparticles in a microfluidic device. The rotation of barium titanate microparticles is observed in 2-propanol and methanol solvent at a frequency below 1 kHz. A particle rotation rate as high as 240 revolutions per minute is observed. It is demonstrated that precise manipulation (both rotation rate and equilibrium position) of the particles is possible by controlling the frequency of the applied electric field. At low frequency range, the equilibrium positions of the microparticles are observed between the electrode edge and electrode center. This method of particle manipulation is different from electrorotation as it uses induced AC electroosmosis instead of electric torque as in the case of electrorotation. Moreover, it has been shown that a microparticle can be rotated along its own axis without any translational motion. PMID:27014394

  2. DESIGN OF AN AC-DIPOLE FOR USE IN RHIC.

    SciTech Connect

    PARKER,B.; BAI,M.; JAIN,A.; MCINTYRE,G.; METH,M.; PEGGS,S.; ROSER,T.; SANDERS,R.; TRBOJEVIC,D.

    1999-03-29

    We present two options for implementing a pair of AC-dipoles in RHIC for spin flipping, measuring linear optical functions and nonlinear diagnostics. AC-dipoles are magnets that can be adiabatically excited and de-excited with a continuous sine-wave in order to coherently move circulating beam out to large betatron amplitudes without incurring emittance blow up [1]. The AGS already uses a similar device for getting polarized proton beams through depolarizing resonances [2]. By placing the magnets in the IP4 common beam region, two AC-dipoles are sufficient to excite both horizontal and vertical motion in both RHIC rings. While we initially investigated an iron-dominated magnet design using available steel tape cores; we now favor a new air coil plus ferrite design featuring mechanical frequency tuning, in order to best match available resources to demanding frequency sweeping requirements. Both magnet designs are presented here along with model magnet test results. The challenge is to make AC-dipoles available for year 2000 RHIC running.

  3. 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.

  4. Three phase AC motor controller

    DOEpatents

    Vuckovich, Michael; Wright, Maynard K.; Burkett, John P.

    1984-03-20

    A motor controller for a three phase AC motor (10) which is adapted to operate bidirectionally from signals received either from a computer (30) or a manual control (32). The controller is comprised of digital logic circuit means which implement a forward and reverse command signal channel (27, 29) for the application of power through the forward and reverse power switching relays (16, 18, 20, 22). The digital logic elements are cross coupled to prevent activation of both channels simultaneously and each includes a plugging circuit (65, 67) for stopping the motor upon the removal of control signal applied to one of the two channels (27, 29) for a direction of rotation desired. Each plugging circuit (65, 67) includes a one-shot pulse signal generator (88, 102) which outputs a single pulse signal of predetermined pulsewidth which is adapted to inhibit further operation of the application of power in the channel which is being activated and to apply a reversal command signal to the other channel which provides a reversed phase application of power to the motor for a period defined by the pulse-width output of the one-shot signal generator to plug the motor (10) which will then be inoperative until another rotational command signal is applied to either of the two channels.

  5. AC impedance spectroscopy studies on solid-state sintered zinc aluminum oxide (ZnAl2O4) ceramics

    NASA Astrophysics Data System (ADS)

    Kumar, B. Rajesh; Rao, T. Subba

    2012-07-01

    In the present investigation Zinc Aluminum Oxide (ZnAl2O4) is prepared by solid-state reaction technique. Dielectric constant (ɛ'), dielectric loss(tan δ), ac conductivityac) as a function of temperature are studied by varying frequencies from 100 Hz to 1MHz using an impedance analyzer. The dielectric constant and dielectric loss increases gradually with an increase of temperature, but it decreases with increase of frequency. The ac conductivityac) also increases with increases of frequency. The transition peaks for ZnAl2O4 are observed at 490°C, 510°C, 520°C for the frequencies 1 KHz, 10 KHz and 100 KHz. No transition peaks are found for the frequency 100 Hz and 1 MHz because of high conductive loss.

  6. Memory effect in ac plasma displays

    NASA Astrophysics Data System (ADS)

    Szlenk, K.; Obuchowicz, E.

    1993-10-01

    The bistable or `memory' mode of operation of an ac plasma display panel is presented. The difference between dc and ac plasma panel operation from the point of view of memory function is discussed. The graphic ac plasma display with thin film Cr-Cu-Cr electrodes was developed in OBREP and its basic parameters are described. It consists of 36 X 59 picture elements, its outer dimensions are: 76 X 52 mm2 and the screen size is: 49 X 30 mm2. The different dielectric glass materials were applied as dielectric layers and the influence of the properties of these materials on display parameters and memory function was investigated.

  7. 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.

  8. Modeling and performance analysis of the fractional order quadratic Boost converter in discontinuous conduction mode-discontinuous conduction mode

    NASA Astrophysics Data System (ADS)

    Tan, Cheng; Liang, Zhi-Shan

    2016-03-01

    In this paper, based on the fact that the inductors and capacitors are of fractional order in nature, the four-order mathematical model of the fractional order quadratic Boost converter in type I and type II discontinuous conduction mode (DCM) — DCM is established by using fractional calculus theory. Direct current (DC) analysis is conducted by using the DC equivalent model and the transfer functions are derived from the corresponding alternating current (AC) equivalent model. The DCM-DCM regions of type I and type II are obtained and the relations between the regions and the orders are found. The influence of the orders on the performance of the quadratic Boost converter in DCM-DCM is verified by numerical and circuit simulations. Simulation results demonstrate the correctness of the fractional order model and the efficiency of the proposed theoretical analysis.

  9. Evaluation of semiconductor devices for Electric and Hybrid Vehicle (EHV) ac-drive applications, volume 1

    NASA Technical Reports Server (NTRS)

    Lee, F. C.; Chen, D. Y.; Jovanovic, M.; Hopkins, D. C.

    1985-01-01

    The results of evaluation of power semiconductor devices for electric hybrid vehicle ac drive applications are summarized. Three types of power devices are evaluated in the effort: high power bipolar or Darlington transistors, power MOSFETs, and asymmetric silicon control rectifiers (ASCR). The Bipolar transistors, including discrete device and Darlington devices, range from 100 A to 400 A and from 400 V to 900 V. These devices are currently used as key switching elements inverters for ac motor drive applications. Power MOSFETs, on the other hand, are much smaller in current rating. For the 400 V device, the current rating is limited to 25 A. For the main drive of an electric vehicle, device paralleling is normally needed to achieve practical power level. For other electric vehicle (EV) related applications such as battery charger circuit, however, MOSFET is advantageous to other devices because of drive circuit simplicity and high frequency capability. Asymmetrical SCR is basically a SCR device and needs commutation circuit for turn off. However, the device poses several advantages, i.e., low conduction drop and low cost.

  10. Fabrication of a flexible Ag-grid transparent electrode using ac based electrohydrodynamic Jet printing

    NASA Astrophysics Data System (ADS)

    Park, Jaehong; Hwang, Jungho

    2014-10-01

    In the dc voltage-applied electrohydrodynamic (EHD) jet printing of metal nanoparticles, the residual charge of droplets deposited on a substrate changes the electrostatic field distribution and interrupts the subsequent printing behaviour, especially for insulating substrates that have slow charge decay rates. In this paper, a sinusoidal ac voltage was used in the EHD jet printing process to switch the charge polarity of droplets containing Ag nanoparticles, thereby neutralizing the charge on a polyethylene terephthalate (PET) substrate. Printed Ag lines with a width of 10 µm were invisible to the naked eye. After sintering lines with 500 µm of line pitch at 180 °C, a grid-type transparent electrode (TE) with a sheet resistance of ˜7 Ω sq-1 and a dc to optical conductivity ratio of ˜300 at ˜84.2% optical transmittance was obtained, values that were superior to previously reported results. In order to evaluate the durability of the TE under bending stresses, the sheet resistance was measured as the number of bending cycles was increased. The sheet resistance of the Ag grid electrode increased only slightly, by less than 20% from its original value, even after 500 cycles. To the best of our knowledge, this is the first time that Ag (invisible) grid TEs have been fabricated on PET substrates by ac voltage applied EHD jet printing.

  11. Effects of airflow on the distribution of filaments in atmospheric AC dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Fan, Zhihui; Qi, Haicheng; Liu, Yidi; Yan, Huijie; Ren, Chunsheng

    2016-12-01

    Atmospheric-pressure dielectric barrier discharge (DBD) accompanied by airflow has attracted a significant attention for its extensive applications. In this paper, the effects of airflow on the characteristics of the atmospheric air DBD plasma are experimentally investigated using the DBD reactor excited by a 15 kHz AC power source. In order to study the discharge filaments distribution at different flow rates, transparent conductive indium tin oxide film is used as the upper electrode, and quartz glasses are used as insulated dielectrics. Experiment results prove that the breakdown voltage is decreased and more current pulses with declined amplitudes are produced when the airflow is introduced into the discharge gap. It is confirmed that although the discharge seems to be diffuse in the presence of airflow to the naked eyes, the discharge mode remains filamentary in the intensified charge-coupled device images within a single AC cycle. By acquiring the images with a different exposure time, it can be recognized that the discharge filaments move along the flow field direction with a velocity less than the corresponding flow rate. The movement of discharge filaments is attributed to the motion of the charge induced by the airflow.

  12. Inhibitory effect of açaí (Euterpe oleracea Mart.) pulp on IgE-mediated mast cell activation.

    PubMed

    Horiguchi, Tomoko; Ishiguro, Nahoko; Chihara, Kazuyasu; Ogi, Kazuhiro; Nakashima, Kenji; Sada, Kiyonao; Hori-Tamura, Naoko

    2011-05-25

    The palm fruit açaí is known to have potential health benefits due to its antioxidant scavenging capacities. Pretreatment of IgE-sensitized mouse primary cultured mast cells with açaí pulp resulted in the dramatic suppression of antigen-induced degranulation in a dose-dependent manner. Similarly, açaí suppressed IgE-mediated degranulation and transcription of the cytokine genes from a cultured mast cell line of rat basophilic leukemia (RBL)-2H3 cells. Açaí could selectively inhibit FcεRI signaling pathways. Furthermore, the FcεRI-mediated complementary signaling pathway was also suppressed by açaí. These results demonstrate that açaí is a potent inhibitor of IgE-mediated mast cell activation.

  13. Ossicular resonance modes of the human middle ear for bone and air conduction

    PubMed Central

    Homma, Kenji; Du, Yu; Shimizu, Yoshitaka; Puria, Sunil

    2009-01-01

    The mean resonance frequency of the human middle ear under air conduction (AC) excitation is known to be around 0.8–1.2 kHz. However, studies suggest that the mean resonance frequency under bone conduction (BC) excitation is at a higher frequency around 1.5–2 kHz. To identify the cause for this difference, middle-ear responses to both AC and BC excitations were measured at the umbo and lateral process of the malleus using five human cadaver temporal bones. The resonance modes identified from these measurements, along with finite element analysis results, indicate the presence of two ossicular modes below 2 kHz. The dominant mode under AC excitation is the first mode, which typically occurs around 1.2 kHz and is characterized by a “hinging” ossicular motion, whereas the dominant mode under BC excitation is the second mode, which typically occurs around 1.7 kHz and is characterized by a “pivoting” ossicular motion. The results indicate that this second mode is responsible for the translational component in the malleus handle motion. The finding is also consistent with the hypothesis that a middle-ear structural resonance is responsible for the prominent peak seen at 1.5–2 kHz in BC limit data. PMID:19206873

  14. Measurement of AC electrical characteristics of SSC superconducting dipole magnets

    SciTech Connect

    Smedley, K M; Shafer, R E

    1992-01-01

    Experiments were conducted to measure the AC electrical characteristics of SSC superconducting dipole magnets over the frequency range of 0.1 Hz to 10 kHz. A magnet equivalent circuit representing the magnet DC inductance, eddy current losses, coil-to-ground and turn-to-turn capacitance, was synthesized from the experimental data. This magnet equivalent circuit can be used to predict the current ripple distribution along the superconducting magnet string and can provide dynamic information for the design of the collider current regulation loop.

  15. AC electrical properties of FeIn2S4

    NASA Astrophysics Data System (ADS)

    Niftiev, N. N.; Tagiev, O. B.; Muradov, M. B.; Mamedov, F. M.

    2012-04-01

    The frequency and temperature dependences of the ac capacitance and resistivity of FeIn2S4 semiconductors are studied. Resonances are observed at certain temperatures in the frequency range (2.5-5.0) × 105 Hz. The permittivity of the crystals and the activation energy of charge carriers are determined. It is found that electrical conduction in the given temperature interval is governed by an activation mechanism. The activation energy is frequency-dependent, because the relaxation time of barrier layers decreases with rising frequency.

  16. Effective conductivities of a positive electrode in an Li-Al/FeS cell at different states of charge

    NASA Astrophysics Data System (ADS)

    Hiroi, M.; Shimotake, H.

    1983-01-01

    Effective conductivities of porous electrodes containing FeS as the initial active material and 54 weight percent (w/o) LiCl-KC electrolyte were experimentally determined at 450 C for different states of charge by means of an a-c impedance bridge. The effective conductivity of the fully charged FeS electrode was found to be approximately 7/ohm-cm, about four times higher than the conductivity of the electrolyte. This high effective conductivity is considered to be one of the superior features of the FeS cells because such high conductivity results in high power density without the addition of conductive material. The change of the electrode effective resistance during the discharge is discussed in connection with both the electrode reactions and the results of metallographic examinations.

  17. High School Teachers Win ACS Prizes

    NASA Astrophysics Data System (ADS)

    Editorial Staff, Jce

    2009-07-01

    William E. Snyder is the 2009 winner of the ACS Division of Chemical Education Central Region Award for Excellence in High School Teaching; Sally Mitchell is the winner of the 2009 James Bryant Conant Award in High School Chemistry Teaching.

  18. Three-phase-to-two-phase direct AC-AC converter with three leg structure

    NASA Astrophysics Data System (ADS)

    Kwak, S.-S.

    2014-05-01

    A three-phase-to-two-phase ac-ac converter is, along with a modulation strategy based on the space vector scheme, introduced to directly drive two-phase output ac systems with high input power quality. The converter is capable of synthesising two sinusoidal output voltages with variable output frequency and arbitrary magnitude in quadrature phase-shift as well as sinusoidal input currents.

  19. Shape Oscillation of a drop in ac electrowetting.

    PubMed

    Oh, Jung Min; Ko, Sung Hee; Kang, Kwan Hyoung

    2008-08-05

    A sessile drop oscillates when an ac voltage is applied in electrowetting. The oscillation results from the time-varying electrical force concentrated on the three-phase contact line. Little is known about the feature of drop oscillation in electrowetting. In the present work, the drop oscillations are observed systematically, and a theoretical model is developed to analyze the oscillation. It is revealed that resonance occurs at certain frequencies and the oscillation pattern is significantly dependent on the applied ac frequencies. The domain perturbation method is used to derive the shape-mode equations under the assumptions of a weak viscous effect and small drop deformation. The electrical force concentrated on the three-phase contact line is approximated as a delta function, which is decomposed and substituted into each shape-mode equation as a forcing term. The theoretical results for the shape and frequency responses are compared with experimental results, which shows qualitative agreement.

  20. Phase protection system for ac power lines

    NASA Technical Reports Server (NTRS)

    Wong, W. J. (Inventor)

    1974-01-01

    The system described provides protection for phase sensitive loads from being or remaining connected to ac power lines whenever a phase reversal occurs. It comprises a solid state phase detection circuit, a dc power relay circuit, an ac-to-dc converter for energizing the relay circuit, and a bistable four terminal transducer coupled between the phase detection circuit and the power relay circuit, for controlling both circuits.

  1. 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.

  2. 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.

  3. 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.

  4. Enhanced ionic conductivity of AgI nanowires/AAO composites fabricated by a simple approach

    NASA Astrophysics Data System (ADS)

    Liu, Li-Feng; Lee, Seung-Woo; Li, Jing-Bo; Alexe, Marin; Rao, Guang-Hui; Zhou, Wei-Ya; Lee, Jae-Jong; Lee, Woo; Gösele, Ulrich

    2008-12-01

    AgI nanowires/anodic aluminum oxide (AgI NWs/AAO) composites have been fabricated by a simple approach, which involves the thermal melting of AgI powders on the surface of the AAO membrane, followed by the infiltration of the molten AgI inside the nanochannels. As-prepared AgI nanowires have corrugated outer surfaces and are polycrystalline according to scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. X-ray diffraction (XRD) shows that a considerable amount of 7H polytype AgI exists in the composites, which is supposed to arise from the interfacial interactions between the embedded AgI and the alumina. AC conductivity measurements for the AgI nanowires/AAO composites exhibit a notable conductivity enhancement by three orders of magnitude at room temperature compared with that of pristine bulk AgI. Furthermore, a large conductivity hysteresis and abnormal conductivity transitions were observed in the temperature-dependent conductivity measurements, from which an ionic conductivity as high as 8.0 × 102 Ω-1 cm-1 was obtained at around 70 °C upon cooling. The differential scanning calorimetry (DSC) result demonstrates a similar phase transition behavior as that found in the AC conductivity measurements. The enhanced ionic conductivity, as well as the abnormal phase transitions, can be explained in terms of the existence of the highly conducting 7H polytype AgI and the formation of well-defined conduction paths in the composites.

  5. 21 CFR 886.1630 - AC-powered photostimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered photostimulator. 886.1630 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1630 AC-powered photostimulator. (a) Identification. An AC-powered photostimulator is an AC-powered device intended to provide light stimulus...

  6. 21 CFR 886.1630 - AC-powered photostimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered photostimulator. 886.1630 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1630 AC-powered photostimulator. (a) Identification. An AC-powered photostimulator is an AC-powered device intended to provide light stimulus...

  7. 21 CFR 886.1850 - AC-powered slitlamp biomicroscope.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered slitlamp biomicroscope. 886.1850... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1850 AC-powered slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an AC-powered device that is...

  8. 21 CFR 886.1850 - AC-powered slitlamp biomicroscope.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered slitlamp biomicroscope. 886.1850... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1850 AC-powered slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an AC-powered device that is...

  9. 21 CFR 888.1240 - AC-powered dynamometer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered dynamometer. 888.1240 Section 888.1240...) MEDICAL DEVICES ORTHOPEDIC DEVICES Diagnostic Devices § 888.1240 AC-powered dynamometer. (a) Identification. An AC-powered dynamometer is an AC-powered device intended for medical purposes to...

  10. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  11. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  12. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  13. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  14. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  15. 21 CFR 888.1240 - AC-powered dynamometer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered dynamometer. 888.1240 Section 888.1240...) MEDICAL DEVICES ORTHOPEDIC DEVICES Diagnostic Devices § 888.1240 AC-powered dynamometer. (a) Identification. An AC-powered dynamometer is an AC-powered device intended for medical purposes to...

  16. Study on phase stability and ionic conductivity in TiIV-substituted bismuth vanadate

    NASA Astrophysics Data System (ADS)

    Beg, Saba; Haneef, Sadaf

    2014-09-01

    The solid solutions Bi4TixV2-xO11-(x/2)-δ in the composition range 0.05 ≤ x ≤ 0.30 were obtained by solid state reaction according to the substitution equation: ? The sample characterization and the study of phase transition were performed by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), alternating current (AC) impedance and electrical conductivity measurements. The solid solutions with composition 0.05 ≤ x ≤ 0.17 are isostructural with the orthorhombic β-phase, and those with x ≥ 0.20 represent tetragonal γ‧-phase as confirmed by the XRD and DSC results. Arrhenius plots of conductivity show that with increase in Ti concentration, the conductivity of solid solutions increase and reaches a maximum value of 4.38 × 10-5 Scm-1 for x = 0.17 at 340 °C. It is seen that the highly conducting tetragonal γ‧-phase is effectively stabilized to room temperature for the composition x ≥ 0.20. AC impedance plots show that the conductivity is mainly due to the grain and the grain boundary contribution which is confirmed by the existence of two semicircles along with an inclined spike.

  17. A 90-day subchronic feeding study of genetically modified maize expressing Cry1Ac-M protein in Sprague-Dawley rats.

    PubMed

    Liu, Pengfei; He, Xiaoyun; Chen, Delong; Luo, Yunbo; Cao, Sishuo; Song, Huan; Liu, Ting; Huang, Kunlun; Xu, Wentao

    2012-09-01

    The cry1Ac-M gene, coding one of Bacillus thuringiensis (Bt) crystal proteins, was introduced into maize H99 × Hi IIB genome to produce insect-resistant GM maize BT-38. The food safety assessment of the BT-38 maize was conducted in Sprague-Dawley rats by a 90-days feeding study. We incorporated maize grains from BT-38 and H99 × Hi IIB into rodent diets at three concentrations (12.5%, 25%, 50%) and administered to Sprague-Dawley rats (n=10/sex/group) for 90 days. A commercialized rodent diet was fed to an additional group as control group. Body weight, feed consumption and toxicological response variables were measured, and gross as well as microscopic pathology were examined. Moreover, detection of residual Cry1Ac-M protein in the serum of rats fed with GM maize was conducted. No death or adverse effects were observed in the current feeding study. No adverse differences in the values of the response variables were observed between rats that consumed diets containing GM maize BT-38 and non-GM maize H99 × Hi IIB. No detectable Cry1Ac-M protein was found in the serum of rats after feeding diets containing GM maize for 3 months. The results demonstrated that BT-38 maize is as safe as conventional non-GM maize.

  18. Dynamic performance of a STATCON at an HVDC inverter feeding a very weak AC system

    SciTech Connect

    Zhuang, Y.; Menzies, R.W.; Nayak, O.B.; Turanli, H.M.

    1996-04-01

    This paper investigates the dynamic performance of the advanced static var compensator or STATCON at a high voltage direct current (HVDC) converter terminal where the ac system has a very low short circuit ratio (SCR). The STATCON is based on a nine-level GTO thyristor inverter. The studies include operating characteristics of the STATCON under various ac and dc disturbances. The simulation results are compared with other types of reactive power compensation options available for such applications. It is shown that the STATCON has clear advantages over the other compensators, in areas such as; fault response time, voltage support ability, and dc recovery, while operating with very weak ac systems.

  19. EMTP modeling of CIGRE benchmark based HVDC transmission system operating with weak AC systems

    SciTech Connect

    Sood, V.K.; Khatri, V.; Jin, H.

    1995-12-31

    An EMTP based study of a CIGRE benchmark based HVDC system operating with weak ac systems is carried out. The modeled system provides a starting point for (a) educators teaching HVDC transmission courses and (b) for utility planners to develop their own low-cost dedicated digital simulators for training purposes. In this paper, modeling details of the ac-dc system, dc converters and control are presented. To validate the control schemes presented, the HVDC system is tested under ac-dc fault conditions. Results obtained from an EMTP-based study under these fault conditions are also presented in this paper.

  20. Droplet condensation on superhydrophobic surfaces with enhanced dewetting under a tangential AC electric field

    NASA Astrophysics Data System (ADS)

    Yan, Xinzhu; Li, Jian; Li, Licheng; Huang, Zhengyong; Wang, Feipeng; Wei, Yuan

    2016-10-01

    In this Letter, the dewetting behavior of superhydrophobic condensing surfaces under a tangential AC electric field is reported. The surface coverage of condensed droplets only exhibits a negligible increase with time. The jumping frequency of droplets is enhanced. The AC electric field motivates the dynamic transition of droplets from stretch to recoil, resulting in the counterforce propelling droplet jumping. The considerable horizontal component of jumping velocity facilitates droplet departure from superhydrophobic surfaces. Both the amplitude and frequency of AC voltage are important factors for droplet departure and dewetting effect. Thereby, the tangential electric field provides a unique and easily implementable approach to enhance droplet removal from superhydrophobic condensing surfaces.