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Sample records for air conduction ac

  1. 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.

  2. Interlayer thermal conductivity of rubrene measured by ac-calorimetry

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Brill, J. W.

    2013-07-01

    We have measured the interlayer thermal conductivity of crystals of the organic semiconductor rubrene, using ac-calorimetry. Since ac-calorimetry is most commonly used for measurements of the heat capacity, we include a discussion of its extension for measurements of the transverse thermal conductivity of thin crystals of poor thermal conductors, including the limitations of the technique. For rubrene, we find that the interlayer thermal conductivity, ≈0.7 mW/cm . K, is several times smaller than the (previously measured) in-layer value, but its temperature dependence indicates that the interlayer mean free path is at least a few layers.

  3. 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.

  4. Thermal Conductivity of Humid Air

    NASA Astrophysics Data System (ADS)

    Beirão, S. G. S.; Ribeiro, A. P. C.; Lourenço, M. J. V.; Santos, F. J. V.; Nieto de Castro, C. A.

    2012-09-01

    In this article, measurements of the thermal conductivity of humid air as a function of pressure, temperature, and mole fraction of water, for pressures up to 5 MPa and temperatures up to 430 K, for different water contents (up to 10 % vapor mole fraction) are reported. Measurements were performed using a transient hot-wire apparatus capable of obtaining data with an uncertainty of 0.8 % for gases. However, as moist air becomes corrosive above 373 K and at pressures >5 MPa, the apparatus, namely, the pressure vessel and the cells had to be modified, by coating all stainless-steel parts with a titanium nitride thin film coating, about 4 μm thick, obtained by physical vapor deposition. The expanded uncertainty (coverage factor k = 2) of the present experimental thermal conductivity data is 1.7 %, while the uncertainty in the mole fraction is estimated to be better than 0.0006. Experimental details regarding the preparation of the samples, the precautions taken to avoid condensation in the tubes connected to the measuring cell, and the method developed for obtaining reliable values of the water content for the gas mixtures are discussed. A preliminary analysis of the application of the kinetic theory of transport properties in reacting mixtures to interpret the complex dependence of the thermal conductivity of humid air on water composition is addressed.

  5. 14. VIEW OF AIR COMPRESSOR. 1500 kw Westinghouse AC generator ...

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

    14. VIEW OF AIR COMPRESSOR. 1500 kw Westinghouse AC generator steam-turbine unit; beyond is air compressor of Chicago Pneumatic Tool Company, 1920, engineered by Earl E. Know Company, Erie, Pennsylvania. - Juniata Shops, Power Plant & Boiler House, East of Fourth Avenue at Second Street, Altoona, Blair County, PA

  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. Pairing fluctuation ac conductivity of disordered thin films

    NASA Astrophysics Data System (ADS)

    Petković, Aleksandra; Vinokur, Valerii M.

    2013-09-01

    We study temperature T and frequency ω dependence of the in-plane fluctuation conductivity of a disordered superconducting film above the critical temperature. Our calculation is based on the nonlinear sigma model within the Keldysh technique. The fluctuation contributions of different physical origin are found and analyzed in a wide frequency range. In the low-frequency range, ω ≪ T, we reproduce the known leading terms and find additional subleading ones in the Aslamazov-Larkin and the Maki-Thompson contributions to the ac conductivity. We also calculate the density of states ac correction. In the dc case these contributions logarithmically depend on the Ginzburg-Landau rate and are considerably smaller that the leading ones. However, in the ac case an external finite-frequency electromagnetic field strongly suppresses the known Aslamazov-Larkin and Maki-Thompson ac contributions, while the corresponding new terms and the density of states contribution are weakly suppressed and therefore become relevant at finite frequencies.

  8. 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.%.

  9. AC Conductivity and Dielectric Properties of Borotellurite Glass

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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) conductivityac) 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.%.

  10. Structural and AC conductivity study of CdTe nanomaterials

    NASA Astrophysics Data System (ADS)

    Das, Sayantani; Banerjee, Sourish; Sinha, T. P.

    2016-04-01

    Cadmium telluride (CdTe) nanomaterials have been synthesized by soft chemical route using mercapto ethanol as a capping agent. Crystallization temperature of the sample is investigated using differential scanning calorimeter. X-ray diffraction and transmission electron microscope measurements show that the prepared sample belongs to cubic structure with the average particle size of 20 nm. Impedance spectroscopy is applied to investigate the dielectric relaxation of the sample in a temperature range from 313 to 593 K and in a frequency range from 42 Hz to 1.1 MHz. The complex impedance plane plot has been analyzed by an equivalent circuit consisting of two serially connected R-CPE units, each containing a resistance (R) and a constant phase element (CPE). Dielectric relaxation peaks are observed in the imaginary parts of the spectra. The frequency dependence of real and imaginary parts of dielectric permittivity is analyzed using modified Cole-Cole equation. The temperature dependence relaxation time is found to obey the Arrhenius law having activation energy ~0.704 eV. The frequency dependent conductivity spectra are found to follow the power law. The frequency dependence ac conductivity is analyzed by power law.

  11. RG flow of AC conductivity in soft wall model of QCD

    NASA Astrophysics Data System (ADS)

    Bhatnagar, Neha; Siwach, Sanjay

    2016-03-01

    We study the Renormalization Group (RG) flow of AC conductivity in soft wall model of holographic QCD. We consider the charged black hole metric and the explicit form of AC conductivity is obtained at the cutoff surface. We plot the numerical solution of conductivity flow as a function of radial coordinate. The equation of gauge field is also considered and the numerical solution is obtained for AC conductivity as a function of frequency. The results for AC conductivity are also obtained for different values of chemical potential and Gauss-Bonnet couplings.

  12. 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.

  13. 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.

  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. AC conductivity and Dielectric Study of Chalcogenide Glasses of Se-Te-Ge System

    NASA Astrophysics Data System (ADS)

    Salman, Fathy

    2004-01-01

    The ac conductivity and dielectric properties of glassy system SexTe79 - xGe21, with x = 11, 14, 17 at.%, has been studied at temperatures 300 to 450 K and over a wide range of frequencies (50 Hz to 500 kHz). Experimental results indicate that the ac conductivity and the dielectric constants depend on temperature, frequency and Se content. The conductivity as a function of frequency exhibited two components: dc conductivity s dc, and ac conductivity s ac, where s ac ˜ w s. The mechanism of ac conductivity can be reasonably interpreted in terms of the correlated barrier hopping model (CBH). The activation energies are estimated and discussed. The dependence of ac conductivity and dielectric constants on the Se content x can be interpreted as the effect of Se fraction on the positional disorder. The impedance plot at each temperature appeared as a semicircle passes through the origin. Each semicircle is represented by an equivalent circuit of parallel resistance Rb and capacitance Cb.

  16. Dielectric relaxation analysis and Ac conductivity of polyvinyl alcohol/polyacrylonitrile film

    NASA Astrophysics Data System (ADS)

    Abdel-Baset, T. A.; Hassen, A.

    2016-10-01

    A film of 0.98 polyvinyl alcohol (PVA)/0.02 Polyacrylonitrile (PAN) has been prepared using casting method. The dielectric properties were measured as function of temperature and frequency. The dielectric permittivity of PVA is considerably enhanced by doping with PAN. Different relaxation processes have been recognized within the studied ranges of temperature and frequency. The frequency temperature superposition (FTS) is well verified. Frequency and temperature dependence of Ac conductivity, σac, were studied. The conduction mechanism of pure PVA and PVA doped with PAN are discussed. The activation energy either for relaxation or conduction was calculated. Comparison with similar polymeric materials is discussed.

  17. Structural, AC conductivity and dielectric properties of Sr-La hexaferrite

    NASA Astrophysics Data System (ADS)

    Singh, A.; Narang, S. B.; Singh, K.; Sharma, P.; Pandey, O. P.

    2006-03-01

    A series of M-type hexaferrite samples with composition Sr{1-x}La{x}Fe{12}O{19} (x = 0.00, 0.05, 0.15 and 0.25) were prepared by standard ceramic technique. AC electrical conductivity measurements were carried out at different frequencies (20 Hz 1 MHz) and at different temperatures. The dielectric constant and dielectric loss tangent were measured in the same range of frequencies. The experimental results indicate that AC electrical conductivity increases on increasing the frequency as well as the temperature, indicating magnetic semiconductor behavior of the samples. The increase in AC electrical conductivity with frequency and temperature has been explained on the basis of Koops Model whereas dielectric constant and dielectric loss tangent has been explained with the Maxwell Wagner type interfacial polarization in agreement with the Koops phenomenological theory.

  18. 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.

  19. AC Conductivity and Dielectric Relaxation Behavior of Sb2S3 Bulk Material

    NASA Astrophysics Data System (ADS)

    Abd El-Rahman, K. F.; Darwish, A. A. A.; Qashou, Saleem I.; Hanafy, T. A.

    2016-07-01

    The Sb2S3 bulk material was used for next-generation anode for lithium-ion batteries. Alternative current (AC) conductivity, dielectric properties and electric modulus of Sb2S3 have been investigated. The measurements were carried out in the frequency range from 40 Hz to 5 MHz and temperature range from 293 K to 453 K. The direct current (DC) conductivity, σ DC, shows an activated behavior and the calculated activation energy is 0.50 eV. The AC conductivity, σ AC, was found to increase with the increase of temperature and frequency. The conduction mechanism of σ AC was controlled by the correlated barrier hopping model. The behavior of the dielectric constant, ɛ', and dielectric loss index, ɛ'', reveal that the polarization process of Sb2S3 is dipolar in nature. The behavior of both ɛ' and ɛ'' reveals that bulk Sb2S3 has no ferroelectric or piezoelectric phase transition. The dielectric modulus, M, gives a simple method for evaluating the activation energy of the dielectric relaxation. The calculated activation energy from M is 0.045 eV.

  20. Analytic formulation for the ac electrical conductivity in two- temperature, strongly coupled, overdense plasma: FORTRAN subroutine

    SciTech Connect

    Cauble, R.; Rozmus, W.

    1993-10-21

    A FORTRAN subroutine for the calculation of the ac electrical conductivity in two-temperature, strongly coupled, overdense plasma is presented. The routine is the result of a model calculation based on classical transport theory with application to plasmas created by the interaction of short pulse lasers and solids. The formulation is analytic and the routine is self-contained.

  1. 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.

  2. 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.

  3. Irregular primary otolith afferents from the guinea pig utricular and saccular maculae respond to both bone conducted vibration and to air conducted sound.

    PubMed

    Curthoys, Ian S; Vulovic, Vedran; Sokolic, Ljiljana; Pogson, Jacob; Burgess, Ann M

    2012-10-01

    This study sought to identify in guinea pig the peripheral sense organ of origin of otolith irregular primary vestibular afferent neurons having a very sensitive response to both air-conducted sound (ACS) and bone-conducted vibration (BCV). Neurons responding to both types of stimuli were labelled by juxtacellular labelling by neurobiotin. Whole mounts of the maculae showed that some vestibular afferents activated by both ACS and BCV originate from the utricular macula and some from the saccular macula - there is no "afferent specificity" by one sense organ for ACS and the other for BCV - instead some afferents from both sense organs have sensitive responses to both stimuli. The clinical implication of this result is that differential evaluation of the functional status of the utricular and saccular maculae cannot rely on stimulus type (ACS vs BCV), however the differential motor projections of the utricular and saccular maculae allow for differential evaluation of each sense organ.

  4. Irregular primary otolith afferents from the guinea pig utricular and saccular maculae respond to both bone conducted vibration and to air conducted sound.

    PubMed

    Curthoys, Ian S; Vulovic, Vedran; Sokolic, Ljiljana; Pogson, Jacob; Burgess, Ann M

    2012-10-01

    This study sought to identify in guinea pig the peripheral sense organ of origin of otolith irregular primary vestibular afferent neurons having a very sensitive response to both air-conducted sound (ACS) and bone-conducted vibration (BCV). Neurons responding to both types of stimuli were labelled by juxtacellular labelling by neurobiotin. Whole mounts of the maculae showed that some vestibular afferents activated by both ACS and BCV originate from the utricular macula and some from the saccular macula - there is no "afferent specificity" by one sense organ for ACS and the other for BCV - instead some afferents from both sense organs have sensitive responses to both stimuli. The clinical implication of this result is that differential evaluation of the functional status of the utricular and saccular maculae cannot rely on stimulus type (ACS vs BCV), however the differential motor projections of the utricular and saccular maculae allow for differential evaluation of each sense organ. PMID:22814095

  5. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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.

  7. Dielectric relaxation and ac conductivity behaviour of polyvinyl alcohol-HgSe quantum dot hybrid films

    NASA Astrophysics Data System (ADS)

    Sinha, Subhojyoti; Chatterjee, Sanat Kumar; Ghosh, Jiten; Meikap, Ajit Kumar

    2014-07-01

    Here we report a comparative study on the dielectric relaxation and ac conductivity behaviour of pure polyvinyl alcohol (PVA) and PVA-mercury selenide (HgSe) quantum dot hybrid films in the temperature range 298 K ⩽ T ⩽ 420 K and in the frequency range 100 Hz ⩽ f ⩽ 1 MHz. The prepared nanocomposite exhibits a larger dielectric constant as compared to the pure PVA. The real and imaginary parts of the dielectric constants were found to fit appreciably with the modified Cole-Cole equation, from which temperature-dependent values of the relaxation times, free charge carrier conductivity and space charge carrier conductivity were calculated. The relaxation time decreases with the quantum dot's inclusion in the PVA matrix and with an increase in temperature, whereas free charge carrier conductivity and space charge carrier conductivity increases with an increase in temperature. An increase in ac conductivity for the nanocomposites has also been observed, while the charge transport mechanism was found to follow the correlated barrier hopping model in both cases. An easy-path model with a suitable electrical equivalent circuit has been employed to analyse the temperature-dependent impedance spectra. The imaginary part of the complex electric modulus spectra exhibit an asymmetric nature and a non-Debye type of behaviour, which has been elucidated considering a generalized susceptibility function. The electric modulus spectra of the nanocomposite demonstrate a smaller amplitude and broader width, as compared to the pure PVA sample.

  8. 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

  9. 40 CFR 86.167-17 - AC17 Air Conditioning Emissions Test Procedure.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.167-17 AC17 Air Conditioning...-conditioning cycle, a 30-minute soak period under simulated solar heat, followed by measurement of emissions over an SC03 drive cycle and a Highway Fuel Economy Driving Schedule (HFET) drive cycle. The vehicle...

  10. 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.

  11. 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.

  12. 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.

  13. Instabilities across the isotropic conductivity point in a nematic phenyl benzoate under AC driving.

    PubMed

    Kumar, Pramoda; Patil, Shivaram N; Hiremath, Uma S; Krishnamurthy, K S

    2007-08-01

    We characterize the sequence of bifurcations generated by ac fields in a nematic layer held between unidirectionally rubbed ITO electrodes. The material, which possesses a negative dielectric anisotropy epsilona and an inversion temperature for electrical conductivity anisotropy sigmaa, exhibits a monostable tilted alignment near TIN, the isotropic-nematic point. On cooling, an anchoring transition to the homeotropic configuration occurs close to the underlying smectic phase. The field experiments are performed for (i) negative sigmaa and homeotropic alignment, and (ii) weakly positive sigmaa and nearly homeotropic alignment. Under ac driving, the Freedericksz transition is followed by bifurcation into various patterned states. Among them are the striped states that seem to belong to the dielectric regime and localized hybrid instabilities. Very significantly, the patterned instabilities are not excited by dc fields, indicating their possible gradient flexoelectric origin. The Carr-Helfrich mechanism-based theories that take account of flexoelectric terms can explain the observed electroconvective effects only in part. PMID:17616118

  14. Conductivity (ac and dc) in III-V amorphous semiconductors and chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Hauser, J. J.

    1985-02-01

    Variable-range hopping, as evidenced by a resistivity proportional to exp(T-1/4), has been induced in many III-V amorphous semiconductors (InSb, AlSb, and GaAs) and even in chalcogenide glasses (As2Te3, As2Te3-xSex, and GeTe) by depositing films at 77 K. It is therefore remarkable that the same procedure failed to generate variable-range hopping in GaSb, which is one of the less ionic III-V semiconductors. Besides differences in the dc conductivity, there are also different behaviors in the ac conductivity of amorphous semiconductors. The low-temperature ac conductivity of all amorphous semiconductors is proportional to ωsTn with s~=1 and n<1, which is consistent with a model of correlated barrier hopping of electron pairs between paired and random defects. However, in the case of a-SiO2 and a-GeSe2 one finds, in addition, that the capacitance obeys the scaling relation C=A ln(Tω-1), which would suggest a conduction mechanism by tunneling relaxation. Furthermore, this scaling relation cannot be fitted to the data for a-As2Te3, a-InSb, and a-GaSb although the functional dependence of C on T and ω are similar.

  15. 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.

  16. Characteristics of ac capillary discharge produced in electrically conductive water solution

    NASA Astrophysics Data System (ADS)

    DeBaerdemaeker, F.; Simek, M.; Schmidt, J.; Leys, C.

    2007-05-01

    Basic electrical, optical and calorimetric characteristics of an ac (50 Hz) driven capillary discharge produced in a water solution were studied for initial water solution conductivity in the range 50-1000 µS cm-1. Typical current and voltage waveforms and emission intensities produced by several electronically excited species were recorded with high time resolution. The evolution of the electrical current, power and capillary resistance was inspected during positive ac half-cycle for various operational regimes. A fast relaxation of the discharge following a breakdown event was observed. Optical measurements indicate that radiative species are mostly generated during the first few hundreds of nanoseconds of plasma generation and that the average duration of plasma emission induced by a discharge pulse is of the order of a few microseconds. Results of calorimetric measurements are in good agreement with average electrical measurements and support the assumption that the discharge is a constant source of heat delivered to the liquid. Assuming that only a fraction of the heat released inside the capillary can be transported by conduction through the capillary wall and via its orifices, the processes of bubble formation, expulsion and re-filling the capillary with 'fresh' water must play a key role in maintaining a thermal balance during long-time steady-state operation of the device. Furthermore, a simplified numerical model and a first order energy deposition calculation prove the plausibility of the bubble breakdown mechanism.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  18. 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.

  19. Basilar membrane and osseous spiral lamina motion in human cadavers with air and bone conduction stimuli.

    PubMed

    Stenfelt, Stefan; Puria, Sunil; Hato, Naohito; Goode, Richard L

    2003-07-01

    It is generally accepted that bone conduction (BC) stimuli yield a traveling wave on the basilar membrane (BM) and hence stimulate the cochlea by the same mechanisms as normal air conduction (AC). The basis for this is the ability to cancel or mask a BC tone with an AC tone and the ability to generate two tone distortion products with a BC tone and an AC tone. The hypothesis is proposed that BC stimulates the BM not only through the hydrodynamics of the scala vestibuli and scala tympani, but also through osseous spiral lamina (OSL) vibrations. To test this hypothesis the BM and OSL response with AC as well as BC stimulation was measured with a laser Doppler vibrometer. Human temporal bones mounted on a shaker were used to record the velocities of the bone per se, the BM and the OSL. The measurements were then converted to relative BM and OSL velocities. The results from the basal turn of the cochlea show similar behavior with AC and BC stimulation. The motion of the OSL at the edge where it connects to the BM is in phase and is typically 6 dB lower than the BM motion. With BC stimulation, there is less phase accumulation in the OSL after the cochlea is drained; the OSL moves due to inertial forces and resonates at approximately 7 kHz. Inertial vibration of the OSL may partially contribute to the total response of BC sound, especially at the high frequencies, although current models of the cochlea assume a rigid OSL. The measurements reported here can be used to include a flexible OSL in cochlear models.

  20. 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.

  1. 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).

  2. AC conductivity and dielectric behavior of CoAl xFe 2- xO 4

    NASA Astrophysics Data System (ADS)

    Abo El Ata, A. M.; Attia, S. M.; Meaz, T. M.

    2004-01-01

    AC conductivity and dielectric properties have been studied for a series of polycrystalline spinel ferrite with composition CoAl xFe 2- xO 4, as a function of frequency and temperature. The results of AC conductivity were discussed in terms of the quantum mechanical tunneling and small polaron tunneling models. The dispersion of the dielectric constant was discussed in the light of Koops model and hopping conduction mechanism. The dielectric loss tangent tan δ curves exhibits a dielectric relaxation peaks which are attributed to the coincidence of the hopping frequency of the charge carriers with that of the external fields. The AC conductivity, dielectric constant, and dielectric loss tangent were found to increase with increasing the temperature due to the increase of the hopping frequency, while they decrease with increasing Al ion content due to the reduction of iron ions available for the conduction process at the octahedral sites.

  3. Ac conductance and capacitance of carbon black polymer composites during thermal cycling and isothermal annealing

    NASA Astrophysics Data System (ADS)

    Jäger, K.-M.; McQueen, D. H.; Vilcáková, J.

    2002-05-01

    The ac electrical properties of acetylene black composites mixed into ethylene butylacrylate copolymer (EBA) and into poly (methyl methacrylate) (PMMA) have been measured in thermal cycling and isothermal annealing experiments. The results show that changes in electrical properties are due to rearrangement of gaps between the carbon black aggregates. This has been concluded using an exponent z that relates the critical frequency ωc denoting the crossover of the conductivity from the dc-plateau to its frequency-dependent part to the dc conductivity, σdc, according to ωc ∝σdcz. Below the melting range of EBA and the glass transition of PMMA z is about one corresponding to strong variation of the conductivity and weak dependence of the permittivity on the gaps. Above the melting range of EBA z is about 1.5, indicating strong dependence of both the conductivity and the permittivity on the gaps, as predicted by percolation theory. This was not found in the PMMA composites above the glass transition. We conclude that the polymer matrix affects the nature of the gaps between carbon black aggregates, either allowing their size to vary continuously (z about 1) or letting them open and close (z about 1.5).

  4. 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.

  5. Effect of an AC electric field on the conductance of single-wall semiconductor-type carbon nanotubes

    SciTech Connect

    Belonenko, M. B.; Glazov, S. Yu.; Mescheryakova, N. E.

    2010-09-15

    The effect of an ac electric field on the conductance of a system of single-wall semiconductor-type carbon nanotubes placed in a dc electric field is considered. The strength vectors of dc and ac electric fields are directed along the nanotube axis. The electronic system of carbon nanotubes is considered in the context of the Boltzmann kinetic equation in the relaxation-time approximation. The dependence of the current density in the system on the characteristics of applied fields is studied. The effect of absolute negative conductance is detected.

  6. Origin of DC and AC conductivity anisotropy in iron-based superconductors: Scattering rate versus spectral weight effects

    NASA Astrophysics Data System (ADS)

    Schütt, Michael; Schmalian, Jörg; Fernandes, Rafael M.

    2016-08-01

    To shed light on the transport properties of electronic nematic phases, we investigate the anisotropic properties of the AC and DC conductivities. Based on the analytical properties of the former, we show that the anisotropy of the effective scattering rate behaves differently than the actual scattering rate anisotropy and even changes sign as a function of temperature. Similarly, the effective spectral weight acquires an anisotropy even when the plasma frequency is isotropic. These results are illustrated by an explicit calculation of the AC conductivity due to the interaction between electrons and spin fluctuations in the nematic phase of the iron-based superconductors and shown to be in agreement with recent experiments.

  7. High-Efficiency Rooftop Air Conditioners: Small Commercial ACs Could Add Up to Big Energy Savings

    SciTech Connect

    Hollomon, J Bradford; Gilbride, Theresa L.

    2003-04-01

    This paper describes a technology procurement conducted by DOE, PNNL, and the Defense Logistics Agency to increase the availability of energy-efficient, packaged, unitary ''rooftop'' air conditioners. The procurement encourages air conditioner manufacturers to produce equipment that exceeds federal energy efficiency standards by at least 25 percent at a lower first cost. Program developers have also sought to aggregate market demand by organizing groups of large-volume buyers of air conditioning equipment. A Cost Estimator tool developed by PNNL to help consumers determine the cost effectiveness, based on local climate conditions, of purchasing energy efficient air conditioners for their own facilities is also described.

  8. Analytic formulation for the ac electrical conductivity in two-temperature, strongly coupled, overdense plasma: FORTRAN subroutine

    NASA Astrophysics Data System (ADS)

    Cauble, R.; Rozmus, W.

    1993-10-01

    A FORTRAN subroutine for the calculation of the ac electrical conductivity in two-temperature, strongly coupled, overdense plasma is presented. The routine is the result of a model calculation based on classical transport theory with application to plasmas created by the interaction of short pulse lasers and solids. The formulation is analytic and the routine is self-contained.

  9. AC Conductance of a multi-probe conductor and the Generalized Fluctuations

    NASA Astrophysics Data System (ADS)

    Fekete, Paula; Gumbs, Godfrey

    2004-03-01

    We extend the work of Baranger and Stone^1 as well as Stone and Safer^2 by expressing the total current Im through lead m in terms of the AC voltages Vn applied to the leads of a phase coherent multi-probe conductor in an arbitrary static magnetic field and an alternating electric field of frequency ω . Using linear response theory, we obtain the non-local response function σ ( x, x'; ω ) in terms of the eigenfunctions of the unperturbed system as well as the retarded and advanced Green's functions. With the use of perturbation theory to perform impurity averaging, the conductance fluctuations (CF) in mesoscopic systems are evaluated at finite frequency. It is shown that the CF decrease monotonically as ω increases. Also, the frequency scale over which this decrease occurs is given in terms of the diffusion time for an electron to diffuse across the sample. We show that the universality of the CF at zero frequency is not preserved at finite frequency. We present numerical results for six leads attached to the faces of a 3D rectangular prism as well as four leads connected to a 2D sample. It is also shown that at finite frequency, the sample-to-sample CF have the same size as the fluctuations of a given sample as a function of frequency. H.U. Baranger and A.D. Stone, Phys. Rev. B, 40, 8169 (1989) A.D. Stone andA. Safer, IBM Journal of Research and Development, 32, 384 (1988) .

  10. Proteoglycan and collagen expression during human air conducting system development

    PubMed Central

    Godoy-Guzmán, C.; San Martin, S.; Pereda, J.

    2012-01-01

    The lung is formed from a bud that grows and divides in a dichotomous way. A bud is a new growth center which is determined by epithelial-mesenchymal interactions where proteins of the extracellular matrix (ECM) might be involved. To understand this protein participation during human lung development, we examined the expression and distribution of proteoglycans in relation to the different types of collagens during the period in which the air conducting system is installed. Using light microscopy and immunohistochemistry we evaluate the expression of collagens (I, III and VI) and proteoglycans (decorin, biglycan and lumican) between 8 to 10 weeks post fertilization and 11 to 14 weeks of gestational age of human embryo and fetus lungs. We show that decorin, lumican and all the collagen types investigated were expressed at the epithelium-mesenchymal interface, forming a sleeve around the bronchiolar ducts. In addition, biglycan was expressed in both the endothelial cells and the smooth muscle of the blood vessels. Thus, the similar distribution pattern of collagen and proteoglycans in the early developmental stages of the human lung may be closely related to the process of dichotomous division of the bronchial tree. This study provides a new insight concerning the participation of collagens and proteoglycans in the epithelial-mesenchymal interface during the period in which the air conducting system is installed in the human fetal lung. PMID:23027345

  11. 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.

  12. 21 CFR 874.3950 - Transcutaneous air conduction hearing aid system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Conduction Hearing Aid System (TACHAS); Guidance for Industry and FDA.” See § 874.1 for the availability of... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Transcutaneous air conduction hearing aid system... Transcutaneous air conduction hearing aid system. (a) Identification. A transcutaneous air conduction hearing...

  13. Effects of ear-canal pressurization on middle-ear bone- and air-conduction responses

    PubMed Central

    Homma, Kenji; Shimizu, Yoshitaka; Kim, Namkeun; Du, Yu; Puria, Sunil

    2014-01-01

    In extremely loud noise environments, it is important to not only protect one’s hearing against noise transmitted through the air-conduction (AC) pathway, but also through the bone-conduction (BC) pathways. Much of the energy transmitted through the BC pathways is concentrated in the mid-frequency range around 1.5–2 kHz, which is likely due to the structural resonance of the middle ear. One potential approach for mitigating this mid-frequency BC noise transmission is to introduce a positive or negative static pressure in the ear canal, which is known to reduce BC as well as AC hearing sensitivity. In the present study, middle-ear ossicular velocities at the umbo and stapes were measured using human cadaver temporal bones in response to both BC and AC excitations, while static air pressures of ±400 mm H2O were applied in the ear canal. For the maximum negative pressure of −400 mm H2O, mean BC stapes-velocity reductions of about 5–8 dB were observed in the frequency range from 0.8 to 2.5 kHz, with a peak reduction of 8.6(± 4.7) dB at 1.6 kHz. Finite-element analysis indicates that the peak BC-response reduction tends to be in the mid-frequency range because the middle-ear BC resonance, which is typically around 1.5–2 kHz, is suppressed by the pressure-induced stiffening of the middle-ear structure. The measured data also show that the BC responses are reduced more for negative static pressures than for positive static pressures. This may be attributable to a difference in the distribution of the stiffening among the middle-ear components depending on the polarity of the static pressure. The characteristics of the BC-response reductions are found to be largely consistent with the available psychoacoustic data, and are therefore indicative of the relative importance of the middle-ear mechanism in BC hearing. PMID:19944139

  14. A Comparative Study on AC Conductivity and Dielectric Behavior of Multiwalled Carbon Nanotubes and Polyaniline Coated Multiwalled Carbon Nanotubes Filled High Density Polyethylene-Carbon Black Nanocomposites

    SciTech Connect

    Dinesh, P.; Renukappa, N. M.; Siddaramaiah; Lee, J. H.; Jeevananda, T.

    2010-10-04

    This paper presents an experimental investigation on AC conductivity and dielectric behavior of carbon black reinforced high density polyethylene (HDPE-CB) and HDPE-CB filled with multiwalled carbon nanotubes (MWNTs-CB-HDPE) and Polyaniline (PAni) coated MWNTs-CB-HDPE nanocomposites. The electrical properties such as dielectric constant ({epsilon}'), dissipation factor (tan {delta}) and AC conductivity ({sigma}{sub ac}) of nanocomposites have been measured with reference to the weight fraction (0.5 and 1 wt% MWNTs), frequency (75 KHz-30 MHz), temperature (25-90 deg. C) and sea water ageing. The experimental results showed that the increased AC conductivity and dielectric constant of the nanocomposites were influenced by PAni coated MWNTs in HDPE-CB nanocomposites. The value of dielectric constant and tan {delta} decreased with increasing frequency. Further more, above 5 MHz the AC conductivity increases drastically whereas significant effect on tan {delta} was observed in less than 1 MHz.

  15. 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.

  16. History of the technological development of air conduction hearing aids.

    PubMed

    Mudry, A; Dodelé, L

    2000-06-01

    This was a study of the history of the technological development of air conduction hearing aids, and a review of international literature on the subject. The technological evolution of amplification devices, from their origin to the present day, can be divided into seven distinct periods: the period of sound collectors, the period of hearing devices constructed from carbon, the period of vacuum tubes, the transistor period, the period of integrated circuits, the microprocessor period and the period of digital hearing instruments. Throughout these different stages, hearing instruments have progressively developed reaching their present state. The current era is itself undergoing constant development and change. With the introduction of new technologies, we expect that the rate of change will increase rapidly in the future.

  17. 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.

  18. SUBMERGED GRAVEL SCRUBBER DEMONSTRATION AS A PASSIVE AIR CLEANER FOR CONTAINMENT VENTING AND PURGING WITH SODIUM AEROSOLS -- CSTF TESTS AC7 - AC10

    SciTech Connect

    HILLIARD, R K.; MCCORMACK, J D.; POSTMA, A K.

    1981-11-01

    Four large-scale air cleaning tests (AC7 - AC10) were performed in the Containment Systems Test Facility (CS'lF) to demonstrate the performance of a Submerged Gravel Scrubber for cleaning the effluent gas from a vented and purged breeder reactor containment vessel. The test article, comprised of a Submerged Gravel Scrubber (SGS) followed by a high efficiency fiber demister, had a design gas flow rate of 0.47 m{sup 3}/s (1000 ft{sup 3}/min) at a pressure drop of 9.0 kPa (36 in. H{sub 2}O). The test aerosol was sodium oxide, sodium hydroxide, or sodium carbonate generated in the 850-m{sup 3} CSTF vessel by continuously spraying sodium into the air-filled vessel while adding steam or carbon dioxide. Approximately 4500 kg (10,000 lb) of sodium was sprayed over a total period of 100 h during the tests. The SGS/Demister system was shown to be highly efficient (removing ~99.98% of the entering sodium aerosol mass), had a high mass loading capacity, and operated in a passive manner, with no electrical requirement. Models for predicting aerosol capture, gas cooling, and pressure drop are developed and compared with experimental results.

  19. Antennas Designed for Advanced Communications for Air Traffic Management (AC/ATM) Project

    NASA Technical Reports Server (NTRS)

    Zakrajsek, Robert J.

    2000-01-01

    The goal of the Advanced Communications for Air Traffic Management (AC/ATM) Project at the NASA Glenn Research Center at Lewis Field is to enable a communications infrastructure that provides the capacity, efficiency, and flexibility necessary to realize a mature free-flight environment. The technical thrust of the AC/ATM Project is targeted at the design, development, integration, test, and demonstration of enabling technologies for global broadband aeronautical communications. Since Ku-band facilities and equipment are readily available, one of the near-term demonstrations involves a link through a Kuband communications satellite. Two conformally mounted antennas will support the initial AC/ATM communications links. Both of these are steered electronically through monolithic microwave integrated circuit (MMIC) amplifiers and phase shifters. This link will be asymmetrical with the downlink to the aircraft (mobile vehicle) at a throughput rate of greater than 1.5 megabits per second (Mbps), whereas the throughput rate of the uplink from the aircraft will be greater than 100 kilobits per second (kbps). The data on the downlink can be narrow-band, wide-band, or a combination of both, depending on the requirements of the experiment. The AC/ATM project is purchasing a phased-array Ku-band transmitting antenna for the uplink from the test vehicle. Many Ku-band receiving antennas have been built, and one will be borrowed for a short time to perform the initial experiments at the NASA Glenn Research Center at Lewis Field. The Ku-band transmitting antenna is a 254-element MMIC phased-array antenna being built by Boeing Phantom Works. Each element can radiate 100 mW. The antenna is approximately 43-cm high by 24-cm wide by 3.3-cm thick. It can be steered beyond 60 from broadside. The beamwidth varies from 6 at broadside to 12 degrees at 60 degrees, which is typical of phased-array antennas. When the antenna is steered to 60 degrees, the beamwidth will illuminate

  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. Study on AC-DC Electrical Conductivities in Warm Dense Matter Generated by Pulsed-power Discharge with Isochoric Vessel

    NASA Astrophysics Data System (ADS)

    Sasaki, Toru; Ohuchi, Takumi; Takahashi, Takuya; Kawaguchi, Yoshinari; Saito, Hirotaka; Miki, Yasutoshi; Takahashi, Kazumasa; Kikuchi, Takashi; Aso, Tsukasa; Harada, Nob.

    2016-03-01

    To observe AC and DC electrical conductivity in warm dense matter (WDM), we have demonstrated to apply the spectroscopic ellipsometry for a pulsed-power discharge with isochoric vessel. At 10 μs from the beginning of discharge, the generated parameters by using pulsed-power discharge with isochoric vessel are 0.1 ρ s (ρ s: solid density) of density and 4000 K of temperature, respectively. The DC electrical conductivity for above parameters is estimated to be 104 S/m. In order to measure the AC electrical conductivity, we have developed a four-detector spectroscopic ellipsometer with a multichannel spectrometer. The multichannel spectrometer, in which consists of a 16-channel photodiode array, a two-stages voltage adder, and a flat diffraction grating, has 10 MHz of the frequency response with covered visible spectrum. For applying the four-detector spectroscopic ellipsometer, we observe the each observation signal evolves the polarized behavior compared to the ratio as I 1/I 2.

  2. AC-conductance and capacitance measurements for ethanol vapor detection using carbon nanotube-polyvinyl alcohol composite based devices.

    PubMed

    Greenshields, Márcia W C C; Meruvia, Michelle S; Hümmelgen, Ivo A; Coville, Neil J; Mhlanga, Sabelo D; Ceragioli, Helder J; Quispe, Jose C Rojas; Baranauskas, Vitor

    2011-03-01

    We report the preparation of inexpensive ethanol sensor devices using multiwalled carbon nanotube-polyvinyl alcohol composite films deposited onto interdigitated electrodes patterned on phenolite substrates. We investigate the frequency dependent response of the device conductance and capacitance showing that higher sensitivity is obtained at higher frequency if the conductance is used as sensing parameter. In the case of capacitance measurements, higher sensitivity is obtained at low frequency. Ethanol detection at a concentration of 300 ppm in air is demonstrated. More than 80% of the sensor conductance and capacitance variation response occurs in less than 20 s.

  3. A Conductivity Device for Measuring Sulfur Dioxide in the Air

    ERIC Educational Resources Information Center

    Craig, James C.

    1972-01-01

    Described is a general electroconductivity device enabling students to determine sulfur dioxide concentration in a particular location, hopefully leading to a deeper understanding of the problem of air pollution. (DF)

  4. Determination of the Si-conducting polymer interfacial properties using A-C impedance techniques

    NASA Technical Reports Server (NTRS)

    Nagasubramanian, G.; Di Stefano, Salvador; Moacanin, Jovan

    1985-01-01

    A study was made of the interfacial properties of poly(pyrrole) (PP) deposited electrochemically onto single crystal p-Si surfaces. The interfacial properties are dependent upon the counterions. The formation of 'quasi-ohmic' and 'nonohmic' contacts, respectively, of PP(ClO4) and PP films doped with other counterions (BF4 and para-toluene sulfonate) with p-Si, are explained in terms of the conductivity of these films and the flat band potential, V(fb), of PP relative to that of p-Si. The PP film seems to passivate or block intrinsic surface states present on the p-Si surface. The differences in the impedance behavior of para-toluene sulfonate doped and ClO4 doped PP are compared.

  5. Studies of structural, optical, dielectric relaxation and ac conductivity of different alkylbenzenesulfonic acids doped polypyrrole nanofibers

    NASA Astrophysics Data System (ADS)

    Hazarika, J.; Kumar, A.

    2016-01-01

    Polypyrrole (PPy) nanofibers doped with alkylbenzenesulfonic acids (ABSA) have been synthesized using interfacial polymerization method. HRTEM studies confirm the formation of PPy nanofibers with average diameter ranging from 13 nm to 25 nm. Broad X-ray diffraction peak in 2 θ range 20-23.46° reveals amorphous structure of PPy nanofibers. The ordering or crystallinity of polymer chains increases, while their interplanar spacing (d) and interchain separation (R) decreases for short alkyl chain ABSA doped PPy nanofibers. FTIR studies reveal that short alkyl chain ABSA doped PPy nanofibers show higher value of "effective conjugation length". PPy nanofibers doped with short alkyl chain ABSA dopant exhibit smaller optical band gap. TGA studies show enhanced thermal stability of short alkyl chain ABSA doped PPy nanofibers. Decrease in dielectric permittivity ε ‧ (ω) with increasing frequency suggests presence of electrode polarization effects. Linear decrease in dielectric loss ε ″ (ω) with increasing frequency suggests dominant effect of dc conductivity process. Low value of non-exponential exponent β (<1) reveals non-Debye relaxation of charge carriers. Scaling of imaginary modulus (M ″) reveals that the charge carriers follow the same relaxation mechanism. Moreover, the charge carriers in PPy nanofibers follow the correlated barrier hopping (CBH) transport mechanism.

  6. Impact of aviation emissions on UTLS and air quality in current and future climate - GEM-AC model simulations

    NASA Astrophysics Data System (ADS)

    Kaminski, J. W.

    2015-12-01

    The objective of this study is to investigate the potential impacts of aviation emissions on the upper troposphere and lower stratosphere (UTLS) and surface air quality. The tool that was used in our study is the GEM-AC (Global Environmental Multiscale with Atmospheric Chemistry) chemical weather model where air quality, free tropospheric and stratospheric chemistry processes are on-line and interactive in a weather forecast model of Environment Canada. In vertical, the model domain is defined on 70 hybrid levels from the surface to ~60km. The gas-phase chemistry includes a comprehensive set of reactions for Ox, NOx, HOx, CO, CH4, NMVOCs, halocarbons, ClOx and BrO. Also, the model can address aerosol microphysics and gas-aerosol partitioning. Aircraft emissions are provided by the AEDT 2006 database developed by the Federal Aviation Administration. Results from model simulations on a global variable grid with 1 degree uniform resolution in the northern hemisphere will be presented.

  7. Ion-pair formation in aqueous strontium chloride and strontium hydroxide solutions under hydrothermal conditions by AC conductivity measurements.

    PubMed

    Arcis, H; Zimmerman, G H; Tremaine, P R

    2014-09-01

    Frequency-dependent electrical conductivities of solutions of aqueous strontium hydroxide and strontium chloride have been measured from T = 295 K to T = 625 K at p = 20 MPa, over a very wide range of ionic strength (3 × 10(-5) to 0.2 mol kg(-1)), using a high-precision flow AC conductivity instrument. Experimental values for the concentration-dependent equivalent conductivity, Λ, of the two electrolytes were fitted with the Turq-Blum-Bernard-Kunz ("TBBK") ionic conductivity model, to determine ionic association constants, K(A,m). The TBBK fits yielded statistically significant formation constants for the species SrOH(+) and SrCl(+) at all temperatures, and for Sr(OH)2(0) and SrCl2(0) at temperatures above 446 K. The first and second stepwise association constants for the ion pairs followed the order K(A1)(SrOH(+)) > K(A1)(SrCl(+)) > K(A2)[Sr(OH)2(0)] > K(A2)[SrCl2(0)], consistent with long-range solvent polarization effects associated with the lower static dielectric constant and high compressibility of water at elevated temperatures. The stepwise association constants to form SrCl(+) agree with previously reported values for CaCl(+) to within the combined experimental error at high temperatures and, at temperatures below ∼375 K, the values of log10 KA1 for strontium are lower than those for calcium by up to ∼0.3-0.4 units. The association constants for the species SrOH(+) and Sr(OH)2(0) are the first accurate values to be reported for hydroxide ion pairs with any divalent cation under these conditions.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Theoretical and Experimental Investigation of Heat Conduction in Air, Including Effects of Oxygen Dissociation

    NASA Technical Reports Server (NTRS)

    Hansen, C. Frederick; Early, Richard A.; Alzofon, Frederick E.; Witteborn, Fred C.

    1959-01-01

    Solutions are presented for the conduction of beat through a semi-infinite gas medium having a uniform initial temperature and a constant boundary temperature. The coefficients of thermal conductivity and diffusivity are treated as variables, and the solutions are extended to the case of air at temperatures where oxygen dissociation occurs. These solutions are used together with shock-tube measurements to evaluate the integral of thermal conductivity for air as a function of temperature.

  10. 40 CFR 1066.845 - AC17 air conditioning efficiency test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... voluntary procedure for measuring the net impact of air conditioner operation on CO2 emissions. See 40 CFR... solar heating is disabled for certain test intervals as described in this section. (d) Interior air... tests according to 40 CFR 86.132-00(a) through (g). If the vehicle has been tested within the last...

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  12. 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.

  13. 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.

  14. Dielectric Properties and AC Conduction of 5 wt % ZnBO Doped (Ba,Sr)TiO3 Ceramics for Low Temperature Co-fired Ceramics Applications

    NASA Astrophysics Data System (ADS)

    Kim, Se-Ho; Koh, Jung-Hyuk

    2009-04-01

    ZnBO doped (Ba0.5Sr0.5)TiO3 (BST) ceramic was synthesized by conventional mixed oxide method. 5 wt % ZnBO addition to the BST has lowered the sintering temperature of BST from 1350 to 1100 °C. From the X-ray diffraction analysis, we found that the 5 wt % ZnBO doped BST has the perovskite structure, and any pryo phase was not observed. The dielectric properties and ac conductivity have been investigated at temperature range from 30 to 130 °C with various frequencies (1-100 kHz). The real part of relative dielectric permittivity ɛr' was decreased with increasing the temperature and the frequency. The activation energy for conduction process was calculated from the slope of ac conductivity at 1 kHz. The activation energy calculated through the Arrhenius law was 0.42 eV. In this paper, we will discuss the low-frequency dielectric relaxation and ac conductivity of 5 wt % ZnBO doped BST ceramics in relation to the electrical conduction.

  15. Dielectric spectroscopy studies and ac electrical conductivity on (AuZn)/TiO2/p-GaAs(110) MIS structures

    NASA Astrophysics Data System (ADS)

    Şafak Asar, Yasemin; Asar, Tarık; Altındal, Şemsettin; Özçelik, Süleyman

    2015-09-01

    In this study, we investigated temperature and voltage dependence of dielectric properties and ac electrical conductivityac) of (AuZn)/TiO2/p-GaAs(110) metal-insulator-semiconductor structures in the temperature range of 80-290 K using the capacitance-voltage ? and conductance-voltage ? measurements at 1 MHz. The intersection/crossing behaviour of C-V plots at sufficiently high forward biases and the increase in σac with increasing temperature was attributed to the lack of sufficient number of enough free charge carriers at low temperatures. The values of the dielectric constant (ε‧), dielectric loss (ε″), loss tangent ?, ac electrical conductivityac), the real and imaginary parts of electric modulus (?) were found to be strong functions of temperature and applied bias voltage. The Cole-Cole plots between ? have shown only one semicircle for each temperature. This indicates one of the relaxation processes was suppressed and this can be attributed to the surface polarization effect. On the other hand, ? plot has a peak for each temperature. The ? plots revealed two linear regions with different slopes for sufficiently high forward biases (0.0, 0.5, and 1.0 V) which correspond to low (80-200 K) and moderate/intermediate (230-290 K) temperatures. Thus, the values of activation energy (Ea) were obtained from the slope of these Arrhenius plots for two linear regions as 87.3 and 3.4 meV, respectively, at 1.0 V. On the other hand, Mott plots have only one linear region except for 260 and 290 K and Mott parameters were determined from these plots at 0.0, 0.5 and 1.0 V.

  16. Highly Conductive, Air-Stable Silver Nanowire@Iongel Composite Films toward Flexible Transparent Electrodes.

    PubMed

    Xiong, Weiwei; Liu, Hongliang; Chen, Yongzhen; Zheng, Meiling; Zhao, Yuanyuan; Kong, Xiangbin; Wang, Ying; Zhang, Xiqi; Kong, Xiangyu; Wang, Pengfei; Jiang, Lei

    2016-09-01

    A new type of flexible transparent electrode is designed, by employing wettability-induced selective electroless-welding of silver nanowire (AgNW) networks, together with a thin conductive iongel as the protective layer. The obtained electrode exhibits high optical transmittance, and excellent air-stability without sacrificing conductivity. PMID:27296551

  17. A stably enhanced transparent conductive graphene film obtained using an air-annealing method

    NASA Astrophysics Data System (ADS)

    Song, Xuefen; Wei, Dapeng; Sun, Tai; Yu, Leyong; Yang, Jun; Zhang, Yongna; Fang, Liang; Wei, Dacheng; Shi, Haofei; Du, Chunlei

    2016-08-01

    A simple and effective air-annealing technique was developed to stably improve both the electrical conductivity and light transmission of pristine graphene. After the graphene film was annealed in air at 250 °C for 80 min, the mobility and carrier concentration were both significantly enhanced, and the sheet resistance was greatly reduced with a decrease rate of ∼33%. Meanwhile, the transparency was also improved by more than 3%. The mechanism is carefully discussed. The reason might be that air-annealing conditions provide a suitable atmosphere to etch and remove amorphous carbons. More importantly, the enhanced transparent conductive properties of the air-annealed graphene films were extraordinarily stable, and remained almost unchanged for 100 days.

  18. A stably enhanced transparent conductive graphene film obtained using an air-annealing method

    NASA Astrophysics Data System (ADS)

    Song, Xuefen; Wei, Dapeng; Sun, Tai; Yu, Leyong; Yang, Jun; Zhang, Yongna; Fang, Liang; Wei, Dacheng; Shi, Haofei; Du, Chunlei

    2016-08-01

    A simple and effective air-annealing technique was developed to stably improve both the electrical conductivity and light transmission of pristine graphene. After the graphene film was annealed in air at 250 °C for 80 min, the mobility and carrier concentration were both significantly enhanced, and the sheet resistance was greatly reduced with a decrease rate of ˜33%. Meanwhile, the transparency was also improved by more than 3%. The mechanism is carefully discussed. The reason might be that air-annealing conditions provide a suitable atmosphere to etch and remove amorphous carbons. More importantly, the enhanced transparent conductive properties of the air-annealed graphene films were extraordinarily stable, and remained almost unchanged for 100 days.

  19. Needle-array to Plate DBD Plasma Using Sine AC and Nanosecond Pulse Excitations for Purpose of Improving Indoor Air Quality.

    PubMed

    Zhang, Li; Yang, Dezheng; Wang, Wenchun; Wang, Sen; Yuan, Hao; Zhao, Zilu; Sang, Chaofeng; Jia, Li

    2016-01-01

    In this study, needle-array to plate electrode configuration was employed to generate an atmospheric air diffuse discharge using both nanosecond pulse and sine AC voltage as excitation voltage for the purpose of improving indoor air quality. Different types of voltage sources and electrode configurations are employed to optimize electrical field distribution and improve discharge stability. Discharge images, electrical characteristics, optical emission spectra, and plasma gas temperatures in both sine AC discharge and nanosecond pulse discharge were compared and the discharge stability during long operating time were discussed. Compared with the discharge excited by sine AC voltage, the nanosecond pulsed discharge is more homogenous and stable, besides, the plasma gas temperature of nanosecond pulse discharge is much lower. Using packed-bed structure, where γ- Al2O3 pellets are filled in the electrode gap, has obvious efficacy in the production of homogenous discharge. Furthermore, both sine AC discharge and nanosecond pulse discharge were used for removing formaldehyde from flowing air. It shows that nanosecond pulse discharge has a significant advantage in energy cost. And the main physiochemical processes for the generation of active species and the degradation of formaldehyde were discussed. PMID:27125663

  20. Needle-array to Plate DBD Plasma Using Sine AC and Nanosecond Pulse Excitations for Purpose of Improving Indoor Air Quality

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Yang, Dezheng; Wang, Wenchun; Wang, Sen; Yuan, Hao; Zhao, Zilu; Sang, Chaofeng; Jia, Li

    2016-04-01

    In this study, needle-array to plate electrode configuration was employed to generate an atmospheric air diffuse discharge using both nanosecond pulse and sine AC voltage as excitation voltage for the purpose of improving indoor air quality. Different types of voltage sources and electrode configurations are employed to optimize electrical field distribution and improve discharge stability. Discharge images, electrical characteristics, optical emission spectra, and plasma gas temperatures in both sine AC discharge and nanosecond pulse discharge were compared and the discharge stability during long operating time were discussed. Compared with the discharge excited by sine AC voltage, the nanosecond pulsed discharge is more homogenous and stable, besides, the plasma gas temperature of nanosecond pulse discharge is much lower. Using packed-bed structure, where γ- Al2O3 pellets are filled in the electrode gap, has obvious efficacy in the production of homogenous discharge. Furthermore, both sine AC discharge and nanosecond pulse discharge were used for removing formaldehyde from flowing air. It shows that nanosecond pulse discharge has a significant advantage in energy cost. And the main physiochemical processes for the generation of active species and the degradation of formaldehyde were discussed.

  1. Needle-array to Plate DBD Plasma Using Sine AC and Nanosecond Pulse Excitations for Purpose of Improving Indoor Air Quality

    PubMed Central

    Zhang, Li; Yang, Dezheng; Wang, Wenchun; Wang, Sen; Yuan, Hao; Zhao, Zilu; Sang, Chaofeng; Jia, Li

    2016-01-01

    In this study, needle-array to plate electrode configuration was employed to generate an atmospheric air diffuse discharge using both nanosecond pulse and sine AC voltage as excitation voltage for the purpose of improving indoor air quality. Different types of voltage sources and electrode configurations are employed to optimize electrical field distribution and improve discharge stability. Discharge images, electrical characteristics, optical emission spectra, and plasma gas temperatures in both sine AC discharge and nanosecond pulse discharge were compared and the discharge stability during long operating time were discussed. Compared with the discharge excited by sine AC voltage, the nanosecond pulsed discharge is more homogenous and stable, besides, the plasma gas temperature of nanosecond pulse discharge is much lower. Using packed-bed structure, where γ- Al2O3 pellets are filled in the electrode gap, has obvious efficacy in the production of homogenous discharge. Furthermore, both sine AC discharge and nanosecond pulse discharge were used for removing formaldehyde from flowing air. It shows that nanosecond pulse discharge has a significant advantage in energy cost. And the main physiochemical processes for the generation of active species and the degradation of formaldehyde were discussed. PMID:27125663

  2. Electrical Characteristics, Electrode Sheath and Contamination Layer Behavior of a Meso-Scale Premixed Methane-Air Flame Under AC/DC Electric Fields

    NASA Astrophysics Data System (ADS)

    Chen, Qi; Yan, Limin; Zhang, Hao; Li, Guoxiu

    2016-05-01

    Electrical characteristics of a nozzle-attached meso-scale premixed methane-air flame under low-frequency AC (0-4300 V, 0-500 Hz) and DC (0-3300 V) electric fields were studied. I-V curves were measured under different experimental conditions to estimate the magnitude of the total current 100-102 μA, the electron density 1015-1016 m-3 and further the power dissipation ≤ 0.7 W in the reaction zone. At the same time, the meso-scale premixed flame conductivity 10-4-10-3 Ω-1·m-1 as a function of voltage and frequency was experimentally obtained and was believed to represent a useful order-of magnitude estimate. Moreover, the influence of the collision sheath relating to Debye length (31-98 μm) and the contamination layer of an active electrode on measurements was discussed, based on the combination of simulation and theoretical analysis. As a result, the electrode sheath dimension was evaluated to less than 0.5 mm, which indicated a complex effect of the collision sheath on the current measurements. The surface contamination effect of an active electrode was further analyzed using the SEM imaging method, which showed elements immigration during the contamination layer formation process. supported by National Natural Science Foundation of China (No. 51376021), and the Fundamental Research Fund for Major Universities (No. 2013JBM079)

  3. Electrical Characteristics, Electrode Sheath and Contamination Layer Behavior of a Meso-Scale Premixed Methane-Air Flame Under AC/DC Electric Fields

    NASA Astrophysics Data System (ADS)

    Chen, Qi; Yan, Limin; Zhang, Hao; Li, Guoxiu

    2016-05-01

    Electrical characteristics of a nozzle-attached meso-scale premixed methane-air flame under low-frequency AC (0-4300 V, 0-500 Hz) and DC (0-3300 V) electric fields were studied. I-V curves were measured under different experimental conditions to estimate the magnitude of the total current 100-102 μA, the electron density 1015-1016 m‑3 and further the power dissipation ≤ 0.7 W in the reaction zone. At the same time, the meso-scale premixed flame conductivity 10‑4-10‑3 Ω‑1·m‑1 as a function of voltage and frequency was experimentally obtained and was believed to represent a useful order-of magnitude estimate. Moreover, the influence of the collision sheath relating to Debye length (31–98 μm) and the contamination layer of an active electrode on measurements was discussed, based on the combination of simulation and theoretical analysis. As a result, the electrode sheath dimension was evaluated to less than 0.5 mm, which indicated a complex effect of the collision sheath on the current measurements. The surface contamination effect of an active electrode was further analyzed using the SEM imaging method, which showed elements immigration during the contamination layer formation process. supported by National Natural Science Foundation of China (No. 51376021), and the Fundamental Research Fund for Major Universities (No. 2013JBM079)

  4. Frequency and voltage dependent profile of dielectric properties, electric modulus and ac electrical conductivity in the PrBaCoO nanofiber capacitors

    NASA Astrophysics Data System (ADS)

    Demirezen, S.; Kaya, A.; Yerişkin, S. A.; Balbaşı, M.; Uslu, İ.

    In this study, praseodymium barium cobalt oxide nanofiber interfacial layer was sandwiched between Au and n-Si. Frequency and voltage dependence of ε‧, ε‧, tanδ, electric modulus (M‧ and M″) and σac of PrBaCoO nanofiber capacitor have been investigated by using impedance spectroscopy method. The obtained experimental results show that the values of ε‧, ε‧, tanδ, M‧, M″ and σac of the PrBaCoO nanofiber capacitor are strongly dependent on frequency of applied bias voltage. The values of ε‧, ε″ and tanδ show a steep decrease with increasing frequency for each forward bias voltage, whereas the values of σac and the electric modulus increase with increasing frequency. The high dispersion in ε‧ and ε″ values at low frequencies may be attributed to the Maxwell-Wagner and space charge polarization. The high values of ε‧ may be due to the interfacial effects within the material, PrBaCoO nanofibers interfacial layer and electron effect. The values of M‧ and M″ reach a maximum constant value corresponding to M∞ ≈ 1/ε∞ due to the relaxation process at high frequencies, but both the values of M‧ and M″ approach almost to zero at low frequencies. The changes in the dielectric and electrical properties with frequency can be also attributed to the existence of Nss and Rs of the capacitors. As a result, the change in the ε‧, ε″, tanδ, M‧, M″ and ac electric conductivityac) is a result of restructuring and reordering of charges at the PrBaCoO/n-Si interface under an external electric field or voltage and interface polarization.

  5. 40 CFR 60.2706 - By what date must I conduct the initial air pollution control device inspection?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air pollution control device inspection? 60.2706 Section 60.2706 Protection of Environment... Requirements § 60.2706 By what date must I conduct the initial air pollution control device inspection? (a) The initial air pollution control device inspection must be conducted within 60 days after installation of...

  6. 40 CFR 60.2141 - By what date must I conduct the initial air pollution control device inspection?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air pollution control device inspection? 60.2141 Section 60.2141 Protection of Environment... Compliance Requirements § 60.2141 By what date must I conduct the initial air pollution control device inspection? (a) The initial air pollution control device inspection must be conducted within 60 days...

  7. 40 CFR 60.4895 - By what date must I conduct annual air pollution control device inspections and make any...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Compliance Requirements § 60.4895 By what date must I conduct annual air pollution control device inspections and make any necessary repairs? (a) You must conduct an annual inspection of each air pollution... following the previous annual air pollution control device inspection. (b) Within 10 operating...

  8. 40 CFR 60.4895 - By what date must I conduct annual air pollution control device inspections and make any...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Compliance Requirements § 60.4895 By what date must I conduct annual air pollution control device inspections and make any necessary repairs? (a) You must conduct an annual inspection of each air pollution... following the previous annual air pollution control device inspection. (b) Within 10 operating...

  9. 40 CFR 60.4895 - By what date must I conduct annual air pollution control device inspections and make any...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Compliance Requirements § 60.4895 By what date must I conduct annual air pollution control device inspections and make any necessary repairs? (a) You must conduct an annual inspection of each air pollution... following the previous annual air pollution control device inspection. (b) Within 10 operating...

  10. 40 CFR 60.4895 - By what date must I conduct annual air pollution control device inspections and make any...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Compliance Requirements § 60.4895 By what date must I conduct annual air pollution control device inspections and make any necessary repairs? (a) You must conduct an annual inspection of each air pollution... following the previous annual air pollution control device inspection. (b) Within 10 operating...

  11. 40 CFR 60.2141 - By what date must I conduct the initial air pollution control device inspection?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air pollution control device inspection? 60.2141 Section 60.2141 Protection of Environment... Compliance Requirements § 60.2141 By what date must I conduct the initial air pollution control device inspection? (a) The initial air pollution control device inspection must be conducted within 60 days...

  12. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles; Test... grains of water/pound of dry air. Paragraph (a) of this section discusses the procedure by which a... during a SC03 air conditioning test cycle while operating in an environmental test cell as described...

  13. 21 CFR 874.3950 - Transcutaneous air conduction hearing aid system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3950... occluding the ear canal. The device consists of an air conduction hearing aid attached to a surgically... ear canal. (b) Classification. Class II (special controls). The special control for this device is...

  14. 21 CFR 874.3950 - Transcutaneous air conduction hearing aid system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3950... occluding the ear canal. The device consists of an air conduction hearing aid attached to a surgically... ear canal. (b) Classification. Class II (special controls). The special control for this device is...

  15. 21 CFR 874.3305 - Wireless air-conduction hearing aid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Wireless air-conduction hearing aid. 874.3305 Section 874.3305 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3305 Wireless...

  16. 21 CFR 874.3305 - Wireless air-conduction hearing aid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Wireless air-conduction hearing aid. 874.3305 Section 874.3305 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3305 Wireless...

  17. 21 CFR 874.3950 - Transcutaneous air conduction hearing aid system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3950... occluding the ear canal. The device consists of an air conduction hearing aid attached to a surgically... ear canal. (b) Classification. Class II (special controls). The special control for this device is...

  18. 21 CFR 874.3305 - Wireless air-conduction hearing aid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Wireless air-conduction hearing aid. 874.3305 Section 874.3305 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3305 Wireless...

  19. 21 CFR 874.3950 - Transcutaneous air conduction hearing aid system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3950... system is a wearable sound-amplifying device intended to compensate for impaired hearing without occluding the ear canal. The device consists of an air conduction hearing aid attached to a...

  20. Anisotropies in the Optical ac and dc Conductivities in Lightly Doped La2−xSrxCuO4: The Role of Deep and Shallow Acceptor States

    SciTech Connect

    Gozar, A.; Silva Neto, M.B.; Blumberg, G.; Komiya, S.; Ando, Y.

    2011-06-01

    We investigate the origin of the optical ac and dc conductivity anisotropies observed in the low temperature orthorhombic phase of lightly doped, untwinned La{sub 2-x}Sr{sub x}NiO{sub 4} single crystals. We show that these anisotropies can be naturally ascribed to the emergence of two odd parity, rotational-symmetry-broken, localized impurity acceptor states, one deeper and one shallower, resulting from the trapping of doped holes by the Coulomb potential provided by the Sr ions. These two lowest-energy, p-wave-like states are split by orthorhombicity and are partially filled with holes. This leaves a unique imprint in the optical ac conductivity, which shows two distinct far-infrared continuum absorption energies corresponding to the photoionization of the deep and shallow acceptor states. Furthermore, we argue that the existence of two independent and orthogonal channels for hopping conductivity, directly associated with the two orthorhombic directions, also quantitatively explains the observed low temperature anisotropies in the dc conductivity.

  1. Experimental and Theoretical Study of Heat Conduction for Air up to 5000 K

    NASA Technical Reports Server (NTRS)

    Peng, Tzy-Cheng; Ahtye, Warren F.

    1961-01-01

    The theoretical value of the integral of thermal conductivity is compared with the experimental values from shock-tube measurements. The particular case considered is the one-dimensional nonsteady flow of heat through air at constant pressure. This approach has been previously described in NASA TR R-27. experiment was uncertain because of the large scatter in the experimental data. In this paper, an attempt is made to improve the correlation by use of a more refined calculation of the integral of thermal conductivity, and by use of improved experimental techniques and instrumentation. As a result of these changes, a much closer correlation is shown between the experimental and theoretical heat-flux potentials. This indicates that the predicted values of the coefficient of thermal conductivity for high-temperature air may be suitably accurate for many engineering needs, up to the limits of the test (4600 K).

  2. Validity of diagnostic computer-based air and forehead bone conduction audiometry.

    PubMed

    Swanepoel, De Wet; Biagio, Leigh

    2011-04-01

    Computer-based audiometry allows for novel applications, including remote testing and automation, that may improve the accessibility and efficiency of hearing assessment in various clinical and occupational health settings. This study describes the validity of computer-based, diagnostic air and forehead bone conduction audiometry when compared wtih conventional industry standard audiometry in a sound booth environment. A sample of 30 subjects (19 to 77 years of age) was assessed with computer-based (KUDUwave 5000) and industry standard conventional audiometers (GSI 61) to compare air and bone conduction thresholds and test-retest reliability. Air conduction thresholds for the two audiometers corresponded within 5 dB or less in more than 90% of instances, with an average absolute difference of 3.5 dB (3.8 SD) and a 95% confidence interval of 2.6 to 4.5 dB. Bone conduction thresholds for the two audiometers corresponded within 10 dB or less in 92% of instances, with an average absolute difference of 4.9 dB (4.9 SD) and a 95% confidence interval of 3.6 to 6.1 dB. The average absolute test-retest threshold difference for bone conduction on the industry standard audiometer was 5.1 dB (5.3 SD) and for the computer-based audiometer 7.1 dB (6.4 SD). Computer-based audiometry provided air and bone conduction thresholds within the test-retest reliability limits of industry standard audiometry.

  3. 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.

  4. Association of Long-Term Air Pollution with Ventricular Conduction and Repolarization Abnormalities

    PubMed Central

    Van Hee, Victor C; Szpiro, Adam A; Prineas, Ronald; Neyer, Jonathan; Watson, Karol; Siscovick, David; Park, Sung Kyun; Kaufman, Joel D

    2011-01-01

    Background Short-term exposure to air pollution may affect ventricular repolarization, but there is limited information on how long-term exposures might affect the surface ventricular electrocardiographic (ECG) abnormalities associated with cardiovascular events. We carried out a study to determine whether long-term air pollution exposure is associated with abnormalities of ventricular repolarization and conduction in adults without known cardiovascular disease. Methods A total of 4783 participants free of clinical cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis underwent 12-lead ECG examinations, cardiac-computed tomography and calcium scoring, as well as estimation of air pollution exposure using a finely resolved spatio-temporal model to determine long-term average individual exposure to fine particulate matter (PM2.5) and proximity to major roadways. We assessed ventricular electrical abnormalities including presence of QT prolongation (Rautaharju QTrr criteria) and intraventricular conduction delay (QRS duration > 120 msec). We used logistic regression to determine the adjusted relationship between air pollution exposures and ECG abnormalities. Results A 10 µg/m3-increase in estimated residential PM2.5 was associated with an increased odds of prevalent QT prolongation (adjusted odds ratio [OR]= 1.6 [95% confidence interval (CI)= 1.2 to 2.2]) and intraventricular conduction delay (OR 1.7, 95% CI: 1.0 to 2.6, independent of coronary-artery calcium score. Living near major roadways was not associated with ventricular electrical abnormalities. No significant evidence of effect modification by traditional risk factors or study site was observed. Conclusions This study demonstrates an association between long-term exposure to air pollution and ventricular repolarization and conduction abnormalities in adults without clinical cardiovascular disease, independent of subclinical coronary arterial calcification. PMID:21918454

  5. AC ionic conductivity and DC polarization method of lithium ion transport in PMMA-LiBF4 gel polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Osman, Z.; Mohd Ghazali, M. I.; Othman, L.; Md Isa, K. B.

    2012-01-01

    Polymethylmethacrylate (PMMA)-based gel polymer electrolytes comprising ethylene carbonate-propylene carbonate (EC/PC) mixed solvent plasticizer and various concentrations of lithium tetrafluoroborate (LiBF4) salt are prepared using a solvent casting technique. Electrical conductivity and transference number measurements were carried out to investigate conductivity and charge transport in the gel polymer electrolytes. The conductivity results show that the ionic conductivity of the samples increases when the amount of salt is increased, however decreases after reaching the optimum value. This result is consistent with the transference number measurements. The conductivity-frequency dependence plots show two distinct regions; i.e. at lower frequencies the conductivity increases with increasing frequency and the frequency independent plateau region at higher frequencies. The temperature-dependence conductivity of the films seems to obey the Arrhenius rule.

  6. Performance and cycle life of carbon- and conductive-based air electrodes for rechargeable Zn-air battery applications

    NASA Astrophysics Data System (ADS)

    Chellapandi Velraj, Samgopiraj

    The development of high-performance, cyclically stable bifunctional air electrodes are critical to the commercial deployment of rechargeable Zn-air batteries. The carbon material predominantly used as support material in the air electrodes due to its higher surface area and good electrical conductivity suffers from corrosion at high oxygen evolution overpotentials. This study addresses the carbon corrosion issues and suggests alternate materials to replace the carbon as support in the air electrode. In this study, Sm0.5Sr0.5CoO3-delta with good electrochemical performance and cyclic lifetime was identified as an alternative catalyst material to the commonly used La0.4Ca 0.6CoO3 catalyst for the carbon-based bifunctional electrodes. Also, a comprehensive study on the effects of catalyst morphology, testing conditions on the cycle life as well as the relevant degradation mechanism for the carbon-based electrode was conducted in this dissertation. The cyclic life of the carbon-based electrodes was strongly dependent on the carbon support material, while the degradation mechanisms were entirely controlled by the catalyst particle size/morphology. Some testing conditions like resting time and electrolyte concentration did not change the cyclic life or degradation mechanism of the carbon-based electrode. The current density used for cyclic testing was found to dictate the degradation mechanism leading to the electrode failure. An alternate way to circumvent the carbon corrosion is to replace the carbon support with a suitable electrically-conductive ceramic material. In this dissertation, LaNi0.9Mn0.1O3, LaNi 0.8Co0.2O3, and NiCo2O4 were synthesized and evaluated as prospective support materials due to their good electrical conductivity and their ability to act as the catalyst needed for the bifunctional electrode. The carbon-free electrodes had remarkably higher catalytic activity for oxygen evolution reaction (OER) when compared to the carbon-based electrode. However

  7. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... adding heat from the vehicle's heating system to the interior of the passenger compartment. (2) Section... conditioning system compressor, converted to an equivalent roadload component, to the normal dynamometer... driving the SC03 cycle with the air conditioning system operating. (1) Engine revolutions/minute...

  8. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... adding heat from the vehicle's heating system to the interior of the passenger compartment. (2) Section... conditioning system compressor, converted to an equivalent roadload component, to the normal dynamometer... driving the SC03 cycle with the air conditioning system operating. (1) Engine revolutions/minute...

  9. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... adding heat from the vehicle's heating system to the interior of the passenger compartment. (2) Section... conditioning system compressor, converted to an equivalent roadload component, to the normal dynamometer... driving the SC03 cycle with the air conditioning system operating. (1) Engine revolutions/minute...

  10. Air-pressure tunable depletion width, rectification behavior, and charge conduction in oxide nanotubes.

    PubMed

    Alivov, Yahya; Funke, Hans H; Singh, Vivek; Nagpal, Prashant

    2015-02-01

    Metal-oxide nanotubes provide large surface areas and functionalizable surfaces for a variety of optical and electronic applications. Here we report air-tunable rectifying behavior, depletion width modulation, and two-dimensional (2D) charge conduction in hollow titanium-dioxide nanotubes. The metal contact forms a Schottky-diode in the nanotubes, and the rectification factor (on/off ratio) can be varied by more than 3 orders of magnitude (1-2 × 10(3)) as the air pressure is increased from 2 mTorr to atmospheric pressure. This behavior is explained using a change in depletion width of these thin nanotubes by adsorption of water vapor on both surfaces of a hollow nanotube, and the resulting formation of a metal-insulator-semiconductor (MIS) junction, which controls the 2D charge conduction properties in thin oxide nanotubes.

  11. Microstructure and DC electrical conductivity of spinel nickel ferrite sintered in air and nitrogen atmospheres

    SciTech Connect

    Liu, Baogang; Zhou, Kechao; Li, Zhiyou; Zhang, Dou; Zhang, Lei

    2010-11-15

    In recent years, the development of inert anode materials has gained considerable attention because such materials are capable of producing only environment-friendly O{sub 2} and saving energy during aluminum electrolysis. Nickel ferrite was prepared by a solid-state reaction as the inert anode in this study and its microstructures and direct current conductivities were analyzed in detail regarding the effects of different sintering atmospheres. A single-phase spinel structure was confirmed for all samples by X-ray powder diffraction. The grain sizes and the relative densities of the samples sintered in nitrogen increased by over 7 {mu}m and 10.8%, respectively, compared to those sintered in air. The direct current conductivities of the samples sintered in nitrogen showed a drastic increase compared to those sintered in air, believed to be due to the effects of increased Fe{sup 2+} ion concentration at octahedral sites and the increase of the relative density.

  12. 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.

  13. 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.

  14. 40 CFR 60.2151 - By what date must I conduct the annual air pollution control device inspection?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air pollution control device inspection? 60.2151 Section 60.2151 Protection of Environment... Compliance Requirements § 60.2151 By what date must I conduct the annual air pollution control device inspection? On an annual basis (no more than 12 months following the previous annual air pollution...

  15. 40 CFR 60.5215 - By what date must I conduct annual air pollution control device inspections and make any...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air pollution control device inspections and make any necessary repairs? (a) You must conduct an annual inspection of each air pollution control device used to comply with the emission limits, according to § 60.5220(c), no later than 12 months following the previous annual air pollution control...

  16. 40 CFR 60.5215 - By what date must I conduct annual air pollution control device inspections and make any...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air pollution control device inspections and make any necessary repairs? (a) You must conduct an annual inspection of each air pollution control device used to comply with the emission limits, according to § 60.5220(c), no later than 12 months following the previous annual air pollution control...

  17. 40 CFR 60.2151 - By what date must I conduct the annual air pollution control device inspection?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air pollution control device inspection? 60.2151 Section 60.2151 Protection of Environment... Compliance Requirements § 60.2151 By what date must I conduct the annual air pollution control device inspection? On an annual basis (no more than 12 months following the previous annual air pollution...

  18. 40 CFR 60.2716 - By what date must I conduct the annual air pollution control device inspection?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air pollution control device inspection? 60.2716 Section 60.2716 Protection of Environment... Requirements § 60.2716 By what date must I conduct the annual air pollution control device inspection? On an annual basis (no more than 12 months following the previous annual air pollution control...

  19. 40 CFR 60.5215 - By what date must I conduct annual air pollution control device inspections and make any...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air pollution control device inspections and make any necessary repairs? (a) You must conduct an annual inspection of each air pollution control device used to comply with the emission limits, according to § 60.5220(c), no later than 12 months following the previous annual air pollution control...

  20. 40 CFR 60.5215 - By what date must I conduct annual air pollution control device inspections and make any...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air pollution control device inspections and make any necessary repairs? (a) You must conduct an annual inspection of each air pollution control device used to comply with the emission limits, according to § 60.5220(c), no later than 12 months following the previous annual air pollution control...

  1. Effects of Copper Doping on Dielectric and A.C. Conductivity in Layered Sodium Tri-Titanate Ceramic

    NASA Astrophysics Data System (ADS)

    Shripal; Dwivedi, Shailja; Singh, Rakesh; Tandon, R. P.

    2013-09-01

    Electron paramagnetic resonance (EPR) spectra of 0.01, 0.1 and 1.0 molar percentage (mp) of CuO doped derivatives of layered Na2Ti3O7 ceramic have been reported. The results show that copper substitutes as Cu2+ at Ti4+ octahedral sites. From the dependence of loss tangent (tan δ) and the relative permittivity (ɛ‧) on temperature and frequency, it is concluded that all the derivatives are of polar nature. The relaxation peaks at lower temperatures have been attributed to the presence of different types of dipoles, whereas peaks in the higher temperature region indicate possible ferroelectric phase transition. The dependence of conductivity on temperature show that electron hopping (polaron) conduction exists in a wide span of temperature range. However, the associated interlayer ionic conduction exists in a small temperature range. Interlayer alkali ion hopping mechanism of conduction has been proposed toward higher temperatures. The conductivity versus frequency plots reveal that the polaron conduction plays a prominent role toward the lower temperature side that diminishes with the rise in temperature. The most probable relaxation times for 0.01 and 0.1 mp CuO doped derivatives are almost same but it records an increased value for 1.0 mp doped material. This again attributes to the possible change in the symmetry of copper environment.

  2. A morphological study of the changes in the ultrastructure of a bacterial biofilm disrupted by an ac corona discharge in air

    NASA Astrophysics Data System (ADS)

    Stepanova, Olga; Rybalchenko, Oksana; Astafiev, Alexander; Orlova, Olga; Kudryavtsev, Anatoly; Kapustina, Valentina

    2016-08-01

    The morphology of bacterial cells and biofilms subjected to a low frequency (˜105 Hz) ac (˜10-1 A) corona discharge was investigated using electron microscopy. A low-frequency ac corona discharge in air is shown to have a bactericidal and bacteriostatic effect on Escherichia coli M17 culture at both the cellular and population levels. Corona exposure inhibits the formation of a microbial community and results in the destruction of formed biofilms. This paper presents data on changes in the ultrastructure of cells and biofilms after corona treatment. Our results suggest that the E. coli M17 cells inside biofilms are affected with results similar to sub-lethal and lethal thermal exposure. Some of the biological aspects of colony and biofilm cells death are evaluated. Morphological changes in the ultrastructure of the biofilms under corona treatment are described. Our results indicate that the heating effect is the main factor responsible for the corona-induced inactivation of bacteria.

  3. NanoCapillary Network Proton Conducting Membranes for High Temperature Hydrogen/Air Fuel Cells

    SciTech Connect

    Pintauro, Peter

    2012-07-09

    The objective of this proposal is to fabricate and characterize a new class of NanoCapillary Network (NCN) proton conducting membranes for hydrogen/air fuel cells that operate under high temperature, low humidity conditions. The membranes will be intelligently designed, where a high density interconnecting 3-D network of nm-diameter electrospun proton conducting polymer fibers is embedded in an inert (uncharged) water/gas impermeable polymer matrix. The high density of fibers in the resulting mat and the high ion-exchange capacity of the fiber polymer will ensure high proton conductivity. To further enhance water retention, molecular silica will be added to the sulfonated polymer fibers. The uncharged matrix material will control water swelling of the high ion-exchange capacity proton conducting polymer fibers and will impart toughness to the final nanocapillary composite membrane. Thus, unlike other fuel cell membranes, the role of the polymer support matrix will be decoupled from that of the proton-conducting channels. The expected final outcome of this 5-year project is the fabrication of fuel cell membranes with properties that exceed the DOE’s technical targets, in particular a proton conductivity of 0.1 S/cm at a temperature less than or equal to120°C and 25-50% relative humidity.

  4. Analytic approach to the a.c. conductance method for rapid characterization of interface states in MOS structures

    NASA Astrophysics Data System (ADS)

    Yadava, R. D. S.

    1990-01-01

    Nicollian and Goetzberger's well known integral expression for the equivalent parallel conductance due to interface states Gp/ ω has been given a simple analytical representation which is valid under the condition that interface potential fluctuation parameter σ > 1.5. Previous methods of conductance analysis based upon numerical and/or graphical construction are provided with alternative analytic relations. The earlier parametric numerical relations like ξ p, fw, fD and ln( ξ+/ ξ-) vsσ are described very well by analytic expressions in this paper. A new relation is presented to determine interface state time constant from the width of conductance peak. A new method is presented to determine dependence of σ on interface band bending from Gp/ ω vs bias measurements at just two frequencies. The expedient method of Nicollian, Goetzberger and Lopez utilises the same two curves to determine distribution of interface state density Nss and capture cross section σ p across the band gap. Therefore using the present new method for σ determination and other analytical relations for N ss and σ p determination, the expediency of their method is greatly enhanced. Complete conductance analysis for rapid characterization of the interface is shown to become now a simple straight forward affair, and the amount of data required is also substantially reduced.

  5. Instability of an interface between air and a low conducting liquid subjected to charge injection

    NASA Astrophysics Data System (ADS)

    Chicón, Rafael; Pérez, Alberto T.

    2006-10-01

    We study the linear stability of an interface between air and a low conducting liquid in the presence of unipolar injection of charge. As a consequence of charge injection, a volume charge density builds up in the air gap and a surface charge density on the interface. Above a certain voltage threshold the electrical stresses may destabilize the interface, giving rise to a characteristic cell pattern known as rose-window instability. Contrary to what occurs in the classical volume electrohydrodynamic instability in insulating liquids, the typical cell size is several times larger than the liquid depth. We analyze the linear stability through the usual procedure of decomposing an arbitrary perturbation into normal modes. The resulting homogeneous linear system of ordinary differential equations is solved using a commercial software package. Finally, an analytical method is developed that provides a solution valid in the limit of small wavenumbers.

  6. Heat Transfer Investigation of Air Flow in Microtubes-Part II: Scale and Axial Conduction Effects.

    PubMed

    Lin, Ting-Yu; Kandlikar, Satish G

    2013-03-01

    In this paper, the scale effects are specifically addressed by conducting experiments with air flow in different microtubes. Three stainless steel tubes of 962, 308, and 83 μm inner diameter (ID) are investigated for friction factor, and the first two are investigated for heat transfer. Viscous heating effects are studied in the laminar as well as turbulent flow regimes by varying the air flow rate. The axial conduction effects in microtubes are experimentally explored for the first time by comparing the heat transfer in SS304 tube with a 910 μm ID/2005 μm outer diameter nickel tube specifically fabricated using an electrodeposition technique. After carefully accounting for the variable heat losses along the tube length, it is seen that the viscous heating and the axial conduction effects become more important at microscale and the present models are able to predict these effects accurately. It is concluded that neglecting these effects is the main source of discrepancies in the data reported in the earlier literature.

  7. 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.

  8. 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.

  9. Mathematical equations for heat conduction in the fins of air-cooled engines

    NASA Technical Reports Server (NTRS)

    Harper, R R; Brown, W B

    1923-01-01

    The problem considered in this report is that of reducing actual geometrical area of fin-cooling surface, which is, of course, not uniform in temperature, to equivalent cooling area at one definite temperature, namely, that prevailing on the cylinder wall at the point of attachment of the fin. This makes it possible to treat all the cooling surface as if it were part of the cylinder wall and 100 per cent effective. The quantities involved in the equations are the geometrical dimensions of the fin, thermal conductivity of the material composing it, and the coefficient of surface heat dissipation between the fin and the air streams.

  10. Metallic conductivity and air stability in copper chloride intercalated carbon fibers

    NASA Technical Reports Server (NTRS)

    Oshima, H.; Woollam, J. A.; Yavrouian, A.

    1982-01-01

    Carbon-copper chloride intercalation compounds have been obtained by using variously graphitized carbon fibers as host materials. The resultant conductors are air stable, thermally stable to 450 K, have electrical resistivities as low as 12.9 microohm cm at room temperature, and have metallic conductivity temperature dependencies. These intercalated fibers have tensile strengths of 160000 psi, and Young's moduli of 25 x 10 to the 6th psi. For aerospace use, 1/(resistivity x density) is a figure of merit. On this basis, a reduction in resistivity by a factor of two will make this conductor competitive with copper.

  11. 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.

  12. 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.

  13. Crystal structure and AC conductivity mechanism of [N(C3H7)4]2CoCl4 compound

    NASA Astrophysics Data System (ADS)

    Moutia, N.; Oueslati, A.; Ben Gzaiel, M.; Khirouni, K.

    2016-09-01

    We found that the new organic-inorganic compound [N(C3H7)4]2 CoCl4, crystallizes at room temperature in the centrosymmetric monoclinic system with P21/c space group. The atomic arrangement can be described by an alternation of organic and organic-inorganic layers parallel to the (001) plan. Indeed, the differential scanning calorimetry (DSC) studies indicate a presence of three order-disorder phase transitions located at 332, 376 and 441 K. Furthermore, the conductivity was measured in the frequency range from 200 MHz to 5 MHz and temperatures between 318 K and 428 K using impedance spectroscopy. Analysis of the AC conductivity experimental data obtained, and the frequency exponent s with theoretical models reveals that the correlated barrier hopping (CBH) model is the appropriate mechanism for conduction in the title compound. The analysis of the dielectric constants ε ‧ and ε ″ versus temperature, at several frequencies, shows a distribution of relaxation times. This relaxation is probably due to the reorientational dynamics of [N(C3H7)4]+ cations.

  14. Fluid stimulation elicits hearing in the absence of air and bone conduction--An animal study.

    PubMed

    Perez, Ronen; Adelman, Cahtia; Sohmer, Haim

    2016-01-01

    Conclusion Cochlea can be directly excited by fluid (soft-tissue) stimulation. Objective To determine whether there is no difference in auditory-nerve-brainstem evoked response (ABR) thresholds to fluid stimulation between normal and animal models of post radical-mastoidectomy, as seen in a previous human study. Background It has been shown in humans that hearing can be elicited with stimulation to fluid in the external auditory meatus (EAM), and radical-mastoidectomy cavity. These groups differed in age, initial hearing, and drilling exposure. To overcome this difference, experiments were conducted in sand-rats, first intact, and after inducing a radical-mastoidectomy. Methods The EAM of five sand-rats was filled with 0.3 ml saline. ABR thresholds were determined in response to vibratory stimulation by a clinical bone-vibrator with a plastic rod, applied to the saline in the EAM. Then the tympanic membrane was removed, and malleus dislocated (radical-mastoidectomy model). The cavity was filled with 0.45 ml saline and the ABR threshold was determined in response to vibratory stimulation to the cavity fluid. Results There was no difference in ABR fluid thresholds to EAM and mastoidectomy cavity stimulation. Air-conduction stimulation from the bone-vibrator was not involved (conductive loss due to fluid). Bone-conduction stimulation was not involved (large difference in acoustic impedance between fluid and bone).

  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. Deep rooting plants influence on soil hydraulic properties and air conductivity over time

    NASA Astrophysics Data System (ADS)

    Uteau, Daniel; Peth, Stephan; Diercks, Charlotte; Pagenkemper, Sebastian; Horn, Rainer

    2014-05-01

    Crop sequences are commonly suggested as an alternative to improve subsoil structure. A well structured soil can be characterized by enhanced transport properties. Our main hypothesis was, that different root systems can modify the soil's macro/mesopore network if enough cultivation time is given. We analyzed the influence of three crops with either shallower roots (Festuca arundinacea, fescue) or taproots (Cichorium intybus, chicory and Medicago sativa, alfalfa). The crops where cultivated on a Haplic Luvisol near Bonn (Germany) for one, two or three years. Undisturbed soil cores were taken for measurement of unsaturated hydraulic conductivity and air permeability. The unsaturated conductivity was measured using the evaporation method, monitoring the water content and tension at two depths of each undisturbed soil core. The van Genuchten-Mualem model (1991) was fitted to the measured data. Air permeability was measured in a permeameter with constant flow at low pressure gradient. The measurements were repeated at -1, -3, -6, -15, -30 and -50 kPa matric tension and the model of Ball et al. (1988) was used to describe permeability as function of matric tension. Furthermore, the cores equilibrated at -15 kPa matric tension were scanned with X-Ray computer tomography. By means of 3D image analysis, geometrical features as pore size distribution, tortuosity and connectivity of the pore network was analyzed. The measurements showed an increased unsaturated hydraulic conductivity associated to coarser pores at the taprooted cultivations. A enhanced pore system (related to shrink-swell processes) under alfalfa was observed in both transport measurements and was confirmed by the 3D image analysis. This highly functional pore system (consisting mainly of root paths, earthworm channels and shrinking cracks) was clearly visible below the 75 cm of depth and differentiated significantly from the other two treatments only after three years of cultivation, which shows the time

  17. 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.

  18. Raman, dielectric and AC-conductivity behavior of Dy2O3 contained K0.5Na0.5NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Mahesh, P.; Pamu, D.

    2016-05-01

    Lead-free piezoelectric (K0.5Na0.5)NbO3+ x wt% Dy2O3 (x = 0 - 1.5) (KNND) ceramics have been prepared by solid state reaction method. The effect of Dy2O3 on the dielectric and electrical conductivity responses of KNN ceramics were investigated in a broad temperature (from 133 K to 673 K) and frequency (106 Hz to 108 Hz) range. Temperature dependent dielectric analysis revealed that the polymorphic phase transition orthorhombic to tetragonal transition temperature (TO-T) shifted from 199°C to room temperature with enhanced dielectric permittivity (ɛ' = 994) with the addition of Dy2O3. The effect of Dy2O3 on structural properties of KNND ceramics are analyzed interms of changes in the internal modes of NbO6 octahedra by using Raman spectroscopy. Temperature dependent (133 K - 306 K) AC-conductivity follows the variable range hopping mechanism in different temperature regimes.

  19. Effect of floating conducting objects on critical switching impulse breakdown of air insulation

    SciTech Connect

    Rizk, F.A.M.

    1995-07-01

    The paper analyses the mechanism of breakdown of phase-to-ground and phase-to-phase air insulation in the presence of large conducting floating objects, under critical switching impulse stress. A new physical modeling approach is introduced which involves determination of the potential of the floating object by charge simulation technique, assessment of streamer breakdown and/or leader inception and propagation in the partial gaps and finally predicts the critical breakdown voltage of various configurations. As to phase-to-ground insulation, the investigation covers rod-plane, conductor-plane and conductor-tower leg configurations with different gap spacings as well as different shapes, dimensions and positions of the floating object. The phase-to-phase study additionally includes the effect of negative switching impulse content of the applied stress. The model is in excellent agreement with experiment and provides a novel tool for assessment of the effect of floating objects on switching impulse breakdown of some basic air gap configurations relevant to live line work.

  20. A fast pulsed power source applied to treatment of conducting liquids and air

    SciTech Connect

    Heesch, E.J.M. van; Pemen, A.J.M.; Huijbrechts, P.A.H.J.; Laan, P.C.T. van der; Ptasinski, K.J.; Zanstra, G.J.; Jong, P. de

    2000-02-01

    Two pilot pulsed power sources were developed for fundamental investigations and industrial demonstrations of treatment of conducting liquids. The developed heavy-duty power sources have an output voltage of 100 kV (rise time 10 ns, pulse duration 150 ns, pulse repetition rate maximum 1,000 pps). A pulse energy of 0.5--3 J/pulse and an average pulse power of 1.5 kW have been achieved with an efficiency of about 80%. In addition, adequate electromagnetic compatibility is achieved between the high-voltage pulse sources and the surrounding equipment. Various applications, such as the use of pulsed electric fields (PEF's) or pulsed corona discharges for inactivation of microorganisms in liquids or air, have been tested in the laboratory. For PEF treatment, homogeneous electric fields in the liquid of up to 70 kV/cm at a pulse repetition rate of 10--400 pps could be achieved. The inactivation is found to be 85 kJ/L per log reduction for Pseudomonas fluorescens and 500 kJ/L per log reduction for spores of Bacillus cereus. Corona directly applied to the liquid is found to be more efficient than PEF. With direct corona they achieve 25 kJ/L per log reduction for both Gram positive and Gram negative bacteria. For air disinfection using their corona pulse source, the measured efficiencies are excellent: 2 J/L per log reduction.

  1. Effect of High-Pass Filtering on the Neonatal Auditory Brainstem Response to Air- and Bone-Conducted Clicks.

    ERIC Educational Resources Information Center

    Stuart, Andrew; Yang, Edward Y.

    1994-01-01

    Simultaneous 3- channel recorded auditory brainstem responses (ABR) were obtained from 20 neonates with various high-pass filter settings and low intensity levels. Results support the advocacy of less restrictive high-pass filtering for neonatal and infant ABR screening to air-conducted and bone-conducted clicks. (Author/JDD)

  2. 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.

  3. 49 CFR 232.217 - Train brake tests conducted using yard air.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... (f). (2) At a minimum, yard air pressure shall be 60 psi at the end of the consist or block of cars... device. (3) If the air pressure of the yard test device is less than 80 psi, then a brake pipe leakage...

  4. 49 CFR 232.217 - Train brake tests conducted using yard air.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... (f). (2) At a minimum, yard air pressure shall be 60 psi at the end of the consist or block of cars... device. (3) If the air pressure of the yard test device is less than 80 psi, then a brake pipe leakage...

  5. 49 CFR 232.217 - Train brake tests conducted using yard air.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... (f). (2) At a minimum, yard air pressure shall be 60 psi at the end of the consist or block of cars... device. (3) If the air pressure of the yard test device is less than 80 psi, then a brake pipe leakage...

  6. 49 CFR 232.217 - Train brake tests conducted using yard air.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... (f). (2) At a minimum, yard air pressure shall be 60 psi at the end of the consist or block of cars... device. (3) If the air pressure of the yard test device is less than 80 psi, then a brake pipe leakage...

  7. 49 CFR 232.217 - Train brake tests conducted using yard air.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... (f). (2) At a minimum, yard air pressure shall be 60 psi at the end of the consist or block of cars... device. (3) If the air pressure of the yard test device is less than 80 psi, then a brake pipe leakage...

  8. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  9. Temperature and strain rate effects in high strength high conductivity copper alloys tested in air

    SciTech Connect

    Edwards, D.J.

    1998-03-01

    The tensile properties of the three candidate alloys GlidCop{trademark} Al25, CuCrZr, and CuNiBe are known to be sensitive to the testing conditions such as strain rate and test temperature. This study was conducted on GlidCop Al25 (2 conditions) and Hycon 3HP (3 conditions) to ascertain the effect of test temperature and strain rate when tested in open air. The results show that the yield strength and elongation of the GlidCop Al25 alloys exhibit a strain rate dependence that increases with temperature. Both the GlidCop and the Hycon 3 HP exhibited an increase in strength as the strain rate increased, but the GlidCop alloys proved to be the most strain rate sensitive. The GlidCop failed in a ductile manner irrespective of the test conditions, however, their strength and uniform elongation decreased with increasing test temperature and the uniform elongation also decreased dramatically at the lower strain rates. The Hycon 3 HP alloys proved to be extremely sensitive to test temperature, rapidly losing their strength and ductility when the temperature increased above 250 C. As the test temperature increased and the strain rate decreased the fracture mode shifted from a ductile transgranular failure to a ductile intergranular failure with very localized ductility. This latter observation is based on the presence of dimples on the grain facets, indicating that some ductile deformation occurred near the grain boundaries. The material failed without any reduction in area at 450 C and 3.9 {times} 10{sup {minus}4} s{sup {minus}1}, and in several cases failed prematurely.

  10. 40 CFR 60.4875 - By what date must I conduct the initial air pollution control device inspection and make any...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air pollution control device inspection and make any necessary repairs? 60.4875 Section 60.4875... Initial Compliance Requirements § 60.4875 By what date must I conduct the initial air pollution control device inspection and make any necessary repairs? (a) You must conduct an air pollution control...

  11. 40 CFR 60.4875 - By what date must I conduct the initial air pollution control device inspection and make any...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air pollution control device inspection and make any necessary repairs? 60.4875 Section 60.4875... Initial Compliance Requirements § 60.4875 By what date must I conduct the initial air pollution control device inspection and make any necessary repairs? (a) You must conduct an air pollution control...

  12. 40 CFR 60.4875 - By what date must I conduct the initial air pollution control device inspection and make any...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air pollution control device inspection and make any necessary repairs? 60.4875 Section 60.4875... Initial Compliance Requirements § 60.4875 By what date must I conduct the initial air pollution control device inspection and make any necessary repairs? (a) You must conduct an air pollution control...

  13. 40 CFR 60.4875 - By what date must I conduct the initial air pollution control device inspection and make any...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air pollution control device inspection and make any necessary repairs? 60.4875 Section 60.4875... Initial Compliance Requirements § 60.4875 By what date must I conduct the initial air pollution control device inspection and make any necessary repairs? (a) You must conduct an air pollution control...

  14. 40 CFR 60.5195 - By what date must I conduct the initial air pollution control device inspection and make any...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air pollution control device inspection and make any necessary repairs? 60.5195 Section 60.5195... air pollution control device inspection and make any necessary repairs? (a) You must conduct an air... approved state plan, Federal plan, or delegation, as applicable. For air pollution control...

  15. 40 CFR 60.5195 - By what date must I conduct the initial air pollution control device inspection and make any...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air pollution control device inspection and make any necessary repairs? 60.5195 Section 60.5195... air pollution control device inspection and make any necessary repairs? (a) You must conduct an air... approved state plan, Federal plan, or delegation, as applicable. For air pollution control...

  16. 40 CFR 60.5195 - By what date must I conduct the initial air pollution control device inspection and make any...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air pollution control device inspection and make any necessary repairs? 60.5195 Section 60.5195... air pollution control device inspection and make any necessary repairs? (a) You must conduct an air... approved state plan, Federal plan, or delegation, as applicable. For air pollution control...

  17. 40 CFR 60.5195 - By what date must I conduct the initial air pollution control device inspection and make any...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air pollution control device inspection and make any necessary repairs? 60.5195 Section 60.5195... air pollution control device inspection and make any necessary repairs? (a) You must conduct an air... approved state plan, Federal plan, or delegation, as applicable. For air pollution control...

  18. Auditory Brainstem Response Thresholds to Air- and Bone-Conducted CE-Chirps in Neonates and Adults

    ERIC Educational Resources Information Center

    Cobb, Kensi M.; Stuart, Andrew

    2016-01-01

    Purpose The purpose of this study was to compare auditory brainstem response (ABR) thresholds to air- and bone-conducted CE-Chirps in neonates and adults. Method Thirty-two neonates with no physical or neurologic challenges and 20 adults with normal hearing participated. ABRs were acquired with a starting intensity of 30 dB normal hearing level…

  19. The role of biological system other than auditory air-conduction in the emergence of the hypersonic effect.

    PubMed

    Oohashi, Tsutomu; Kawai, Norie; Nishina, Emi; Honda, Manabu; Yagi, Reiko; Nakamura, Satoshi; Morimoto, Masako; Maekawa, Tadao; Yonekura, Yoshiharu; Shibasaki, Hiroshi

    2006-02-16

    Although human beings cannot perceive elastic vibrations in the frequency range above 20 kHz, nonstationary sounds containing a wealth of inaudible high-frequency components (HFC) above the human audible range activate deep-lying brain structures, including the brainstem and thalamus and evoke various physiological, psychological, and behavioral responses. In the previous reports, we have called these phenomena collectively "the hypersonic effect." It remains unclear, however, if vibratory stimuli above the audible range are transduced and perceived solely via the conventional air-conducting auditory system or if other mechanisms also contribute to mediate transduction and perception. In the present study, we have examined the emergence of the hypersonic effect when inaudible HFC and audible low-frequency components (LFC) were presented selectively to the ears, the entrance of an air-conducting auditory system, or to the body surface including the head which might contain some unknown vibratory sensing mechanisms. We used two independent measurements based on differing principles; one physiological (alpha 2 frequency of spontaneous electroencephalogram [alpha-EEG]) and the other behavioral (the comfortable listening level [CLL]). Only when the listener's entire body surface was exposed to HFC, but not when HFC was presented exclusively to the air-conducting auditory system, did both the alpha-EEG and the CLL significantly increase compared to the presentation of LFC alone, that is to say, there was an evident emergence of the hypersonic effect. The present findings suggest that the conventional air-conducting auditory system alone does not bring about the hypersonic effect. We may need to consider the possible involvement of a biological system distinct from the conventional air-conducting auditory nervous system in sensing and transducing high-frequency elastic vibration above the human audible range.

  20. Air-Stable, High-Conduction Solid Electrolytes of Arsenic-Substituted Li4SnS4

    SciTech Connect

    Sahu, Gayatri; Lin, Zhan; Li, Juchuan; Liu, Zengcai; Dudney, Nancy J; Liang, Chengdu

    2014-01-01

    Lithium-ion-conducting solid electrolytes show promise for enabling high-energy secondary battery chemistries and solving safety issues associated with conventional lithium batteries. Achieving the combination of high ionic conductivity and outstanding chemical stability in solid electrolytes is a grand challenge for the synthesis of solid electrolytes. Herein we report the design of aliovalent substitution of Li4SnS4 to achieve high conduction and excellent air stability based on the hard and soft acids and bases theory. The composition of Li3.833Sn0.833As 0.166S4 has a high ionic conductivity of 1.39 mS/cm 1 at 25 C. Considering the high Li+ transference number, this phase conducts Li+ as well as carbonate-based liquid electrolytes. This research also addresses the compatibility of the sulfide-based solid electrolytes through chemical passivation.

  1. Wind Direction Bias in Generating Wind Roses and Conducting Sector-Based Air-Dispersion Modeling

    SciTech Connect

    Droppo, James G.; Napier, Bruce A.

    2008-07-01

    Certain widely used wind rose programs and air dispersion models use an overly-simple data-transfer algorithm that induces a directional bias in their output products. The purpose of this paper is to provide a revised algorithm that corrects the aliasing bias that occurs when the internals in reported wind direction data are on the same order of magnitude, but not equal to the intervals used in the wind direction summaries. The directional bias issue arises when output products in 22.5-degree sectors are produced from 10-degree wind direction data, which affects the results of simulations of air and surface concentrations using widely applied air-dispersion models. Datasets or models with the bias discussed here give consistent positive biases (approximately 30%) for cardinal direction sectors (north, south, east, and west) and consistent negative biases for all the other sectors (approximately -10%). Data summary and air dispersion programs providing outputs in directions sectors that do not match the observational sectors need to be checked for this bias. A revised data-transfer algorithm is provided that corrects the aliasing bias that can occur in transferring wind direction data between different sectors widths.

  2. 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.

  3. Comparison of DC and AC Transport in 1.5-7.5 nm Oligophenylene Imine Molecular Wires across Two Junction Platforms: Eutectic Ga-In versus Conducting Probe Atomic Force Microscope Junctions.

    PubMed

    Sangeeth, C S Suchand; Demissie, Abel T; Yuan, Li; Wang, Tao; Frisbie, C Daniel; Nijhuis, Christian A

    2016-06-15

    We have utilized DC and AC transport measurements to measure the resistance and capacitance of thin films of conjugated oligophenyleneimine (OPI) molecules ranging from 1.5 to 7.5 nm in length. These films were synthesized on Au surfaces utilizing the imine condensation chemistry between terephthalaldehyde and 1,4-benzenediamine. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy yielded molecular tilt angles of 33-43°. To probe DC and AC transport, we employed Au-S-OPI//GaOx/EGaIn junctions having contact areas of 9.6 × 10(2) μm(2) (10(9) nm(2)) and compared to previously reported DC results on the same OPI system obtained using Au-S-OPI//Au conducting probe atomic force microscopy (CP-AFM) junctions with 50 nm(2) areas. We found that intensive observables agreed very well across the two junction platforms. Specifically, the EGaIn-based junctions showed: (i) a crossover from tunneling to hopping transport at molecular lengths near 4 nm; (ii) activated transport for wires >4 nm in length with an activation energy of 0.245 ± 0.008 eV for OPI-7; (iii) exponential dependence of conductance with molecular length with a decay constant β = 2.84 ± 0.18 nm(-1) (DC) and 2.92 ± 0.13 nm(-1) (AC) in the tunneling regime, and an apparent β = 1.01 ± 0.08 nm(-1) (DC) and 0.99 ± 0.11 nm(-1) (AC) in the hopping regime; (iv) previously unreported dielectric constant of 4.3 ± 0.2 along the OPI wires. However, the absolute resistances of Au-S-OPI//GaOx/EGaIn junctions were approximately 100 times higher than the corresponding CP-AFM junctions due to differences in metal-molecule contact resistances between the two platforms.

  4. Role of conductivity in the electrohydrodynamic patterning of air-liquid interfaces.

    PubMed

    Gambhire, P; Thaokar, R M

    2012-09-01

    The effect of electrical conductivity on the wavelength of an electrohydrodynamic instability of a leaky dielectric-perfect dielectric (LD-PD) fluid interface is investigated. For instabilities induced by dc fields, two models, namely the PD-PD model, which is independent of the conductivity, and the LD-PD model, which shows very weak dependence on the conductivity of the LD fluid, have been previously suggested. In the past, experiments have been compared with either of these two models. In the present work, experiments, analytical theory, and simulations are used to elucidate the dependence of the wavelength obtained under dc fields on the ratio of the instability time (τs=1/smax) and the charge relaxation time (τc=εε0/σ, where ε0 is the permittivity of vacuum, ε is the dielectric constant, and σ is the electrical conductivity). Sensitive dependence of the wavelength on the nondimensional conductivity S2=σ2μ2h0(2)/(ε0(2)φ0(2)δ2) (where σ2 is the electrical conductivity, μ2 is the viscosity, h0 is the thickness of the thin liquid film, φ0 is the rms value of the applied field, and δ is a small parameter) is observed and the PD-PD and the LD-PD cases are observed only as limiting behaviors at very low and very high values of S2, respectively. Under an alternating field, the frequency of the applied voltage can be altered to realize several regimes of relative magnitudes of the three time scales inherent to the system, namely τc, τs, and the time period of the applied field, τf. The wavelength in the various regimes that result from a systematic variation of these three time scales is studied. It is observed that the linear Floquet theory is invalid in most of these regimes and nonlinear analysis is used to complement it. Systematic dependence of the wavelength of the instability on the frequency of the applied field is presented and it is demonstrated that nonlinear simulations are necessary to explain the experimental results.

  5. Thermal Conductivity and Erosion Durability of Composite Two-Phase Air Plasma Sprayed Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Schmitt, Michael P.; Rai, Amarendra K.; Zhu, Dongming; Dorfman, Mitchell R.; Wolfe, Douglas E.

    2015-01-01

    To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7 wt% yttria stabilized zirconia (7YSZ), approximately 1200 C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by approximately 13 and approximately 25%, respectively. The 40 wt% t' Low-k composite (40 wt% t' Low-k - 60 wt% cubic Low-k) showed a approximately 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal in the composite coating. It was observed that a mere 20 wt% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.

  6. 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.

  7. Carrier-envelope phase-dependent electronic conductivity in an air filament driven by few-cycle laser pulses

    NASA Astrophysics Data System (ADS)

    Wang, Lifeng; Lu, Xin; Teng, Hao; Xi, Tingting; Chen, Shiyou; He, Peng; He, Xinkui; Wei, Zhiyi

    2016-07-01

    The modulation of the electron conductivity in an air filament, which is produced by carrier-envelope phase (CEP) stabilized 7-fs laser pulses, is realized experimentally. Numerical results based on a coupled 3D+1 generalized nonlinear Schrödinger equation including the real electric-field dependent ionization model are in good agreement with those from the experiment. It is demonstrated that the CEP effect on the electron density originates from the CEP-induced modification of the electric field of the laser pulse, and this modification is amplified during nonlinear propagation. The results provide important information to help understand the physical mechanism of the filaments driven by few-cycle femtosecond laser pulses.

  8. On the variation in the electrical properties and ac conductivity of through-thickness nano-porous anodic alumina with temperature

    NASA Astrophysics Data System (ADS)

    Tahir, Mahmood; Mehmood, Mazhar; Nadeem, Muhammad; Waheed, Abdul; Tanvir, Muhammad Tauseef

    2013-09-01

    The electrical response of self-organized through-thickness anodic alumina with hexagonal arrangement of cylindrical pores has been studied as a function of temperature. Mechanically stable thick porous anodic alumina was prepared, by through-thickness anodic oxidation of aluminum sheet in sulfuric acid, with extremely high aspect ratio pores exhibiting fairly uniform diameter and interpore distance. It was observed that the electrical properties of through-thickness anodic alumina are very sensitive to minute changes in temperature and the role of surface conductivity in governing its electrical response cannot be overlooked. At high frequencies, intrinsic dielectric response of anodic alumina was dominant. The frequency-dependent conductivity behavior at low and intermediate frequencies was explained on the basis of correlated barrier hopping (CBH) and quantum mechanical tunneling (QMT) models, respectively. Experimental data was modeled using an equivalent circuit consisting of Debye circuit, for bulk alumina, parallel to surface conduction path. The surface conduction was primarily based on two circuits in series, each with a parallel arrangement of a resistor and a constant phase element. This suggested heterogeneity in alumina pore surface, possibly related with islands of physisorbed water separated by the regions of chemisorbed water. Temperature dependence of some circuit elements has been analyzed to express different charge migration phenomena occurring in nano-porous anodic alumina.

  9. 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.

  10. 40 CFR 60.2716 - By what date must I conduct the annual air pollution control device inspection?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air pollution control device inspection? 60.2716 Section 60.2716 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY... annual air pollution control device inspection), you must complete the air pollution control...

  11. 40 CFR 60.2151 - By what date must I conduct the annual air pollution control device inspection?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air pollution control device inspection? 60.2151 Section 60.2151 Protection of Environment... annual air pollution control device inspection? On an annual basis (no more than 12 months following the previous annual air pollution control device inspection), you must complete the air pollution...

  12. 40 CFR 60.2141 - By what date must I conduct the initial air pollution control device inspection?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air pollution control device inspection? 60.2141 Section 60.2141 Protection of Environment... initial air pollution control device inspection? (a) The initial air pollution control device inspection... startup. (b) Within 10 operating days following an air pollution control device inspection, all...

  13. 40 CFR 60.2716 - By what date must I conduct the annual air pollution control device inspection?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air pollution control device inspection? 60.2716 Section 60.2716 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY... annual air pollution control device inspection), you must complete the air pollution control...

  14. 40 CFR 60.2716 - By what date must I conduct the annual air pollution control device inspection?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air pollution control device inspection? 60.2716 Section 60.2716 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY... annual air pollution control device inspection), you must complete the air pollution control...

  15. 40 CFR 60.2141 - By what date must I conduct the initial air pollution control device inspection?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air pollution control device inspection? 60.2141 Section 60.2141 Protection of Environment... initial air pollution control device inspection? (a) The initial air pollution control device inspection... startup. (b) Within 10 operating days following an air pollution control device inspection, all...

  16. 40 CFR 60.2151 - By what date must I conduct the annual air pollution control device inspection?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air pollution control device inspection? 60.2151 Section 60.2151 Protection of Environment... annual air pollution control device inspection? On an annual basis (no more than 12 months following the previous annual air pollution control device inspection), you must complete the air pollution...

  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. An electrical conductivity based method of determining the particle deposition rate in air-liquid interface devices.

    PubMed

    Wiegand, Harald; Meyer, Jörg; Kasper, Gerhard

    2015-08-01

    A new in-situ method of determining the particle deposition rate onto cell cultures inside air-liquid interface devices is described. It is based on depositing a surrogate aerosol of salt particles onto the water filled wells of a culture plate while measuring the resulting change in electrical conductivity of the solution in situ, in order to derive the accumulated particle mass. For evaluation purposes, the wells of a six-well cell culture plate were equipped with custom designed electrodes and calibrated with a series of commercially available standard solutions. After the necessary corrections prescribed by theory, the calibration resulted in an accuracy and comparability between cells of ±3% in terms of measured conductivity. The method was then applied to a specific ALI device consisting essentially of the calibrated six-well culture plate inside an electrostatic cross-flow precipitator, and tested with submicron NaCl aerosol of defined size distribution produced by nebulization of a salt solution. 2h of particle accumulation were sufficient to accumulate between 30 and 10 μg of salt per well, depending on the location in the precipitator. Resulting deposition rates varied narrowly between the wells by about 2 ng min(-1) cm(-2). Factors affecting the overall accuracy and reproducibility are discussed.

  19. 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.

  20. Dielectric behavior and ac conductivity in Aurivillius Bi4Ti3O12 doped by antiferromagnetic BiFeO3

    NASA Astrophysics Data System (ADS)

    Wu, M. S.; Tian, Z. M.; Yuan, S. L.; Duan, H. N.; Qiu, Y.

    2012-06-01

    Bi5Ti3FeO15 ceramics were synthesized by the solid state reaction. XRD analysis shows a single phase perovskite structure with no impurities identified. Two obvious dielectric anomalies around 1007 and 1090 K were exhibited by this material, indicating that there are two phase transitions. While no peak was found in the tan δ-T curve. In addition, the conduction loss activation energies calculated at 476-639 K, 652-966 K, and 980-1095 K are 0.156, 0.262, and 0.707 eV, respectively. Polarization versus electric field hysteresis loops associated with 2Pr of 6.08 μC/cm2 and 2Ec of 59 kV/cm were obtained.

  1. Post-fire Changes in Air Permeability and Hydraulic Conductivity of Soils Following 2003 Aspen Fire in Sabino Canyon, AZ

    NASA Astrophysics Data System (ADS)

    Chief, K.; Ferre, T. P.; Nijssen, B.

    2006-12-01

    As part of a project to study the hydrologic effects of fire on the Sabino Canyon Watershed, the Soil Corer Air Permeameter (SCAP) was developed to rapidly measure in-situ air permeability (k_a) of unburned and burned desert soils while providing a standard soil sample for additional laboratory analysis. Twenty-two unburned and burned plots were selected in woodland-chaparral and coniferous zones with low and high slopes, and low, medium, and high fuel loads or burn severities. Air permeability was measured on a 25-point square grid on each 100 m2 plot (n=445). Hydraulic conductivity (Ksat), water permeability (k_w), soil physical properties, and hydrophobicity measurements were made on extracted soil samples in the laboratory. There was a slight decrease in the median k_a from 95 to 80 μm2 for the woodland- chaparral zone as a result of the wildfire. There was a greater decrease for the coniferous zone where the median decreased from 152 to 110 μm2 following the fire. The k_w of woodland-chaparral soils increased from 192 to 425 μm2; but the median k_w decreased for the coniferous zone from 862 to 444 μm2 after the fire. In addition, hydrophobic measurements show that there was a significant increase in hydrophobicity for post-fire woodland-chaparral soils but not for coniferous soils. The log k_a and log Ksat measurements were highly correlated for the unburned woodland-chaparral soils, but this correlation decreased for burned woodland-chaparral soils. The unburned coniferous data set had the least k_a and Ksat correlation, but was reasonable for burned coniferous soils. The decrease in correlation may be due to increases of hydrophobicity, uneven wetting and preferential flow in Ksat measurements, or extremely rocky terrain. However, the overall, log k_a-log Ksat correlation for all unburned and burned soils including previous measurements on agricultural and alluvial soils follow the trend of the Iversen et al. (2001) log k_a-log Ksat correlation.

  2. 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.

  3. 40 CFR 60.2706 - By what date must I conduct the initial air pollution control device inspection?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air pollution control device inspection? 60.2706 Section 60.2706 Protection of Environment... pollution control device inspection? (a) The initial air pollution control device inspection must be... meeting the amended emission limitations. (b) Within 10 operating days following an air pollution...

  4. 40 CFR 60.2706 - By what date must I conduct the initial air pollution control device inspection?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air pollution control device inspection? 60.2706 Section 60.2706 Protection of Environment... pollution control device inspection? (a) The initial air pollution control device inspection must be... meeting the amended emission limitations. (b) Within 10 operating days following an air pollution...

  5. 40 CFR 60.2706 - By what date must I conduct the initial air pollution control device inspection?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air pollution control device inspection? 60.2706 Section 60.2706 Protection of Environment... pollution control device inspection? (a) The initial air pollution control device inspection must be... meeting the amended emission limitations. (b) Within 10 operating days following an air pollution...

  6. Air and Bone Conduction Click and Tone-burst Auditory Brainstem Thresholds using Kalman Adaptive Processing in Non-sedated Normal Hearing Infants

    PubMed Central

    Elsayed, Alaaeldin M.; Hunter, Lisa L.; Keefe, Douglas H.; Feeney, M. Patrick; Brown, David K.; Meinzen-Derr, Jareen K.; Baroch, Kelly; Sullivan-Mahoney, Maureen; Francis, Kara; Schaid, Leigh G.

    2015-01-01

    Objective To study normative thresholds and latencies for click and tone-burst auditory brainstem response (TB-ABR) for air and bone conduction in normal infants and those discharged from neonatal intensive care units (NICU), who passed newborn hearing screening and follow-up DPOAE. An evoked potential system (Vivosonic Integrity™) that incorporates Bluetooth electrical isolation and Kalman-weighted adaptive processing to improve signal to noise ratios was employed for this study. Results were compared with other published data. Research Design One hundred forty-five infants who passed two-stage hearing screening with transient-evoked otoacoustic emission (OAE) or automated ABR were assessed with clicks at 70 dB nHL and threshold TB-ABR. Tone-bursts at frequencies between 500 to 4000 Hz were employed for air and bone conduction ABR testing using a specified staircase threshold search to establish threshold levels and Wave V peak latencies. Results Median air conduction hearing thresholds using TB-ABR ranged from 0-20 dB nHL, depending on stimulus frequency. Median bone conduction thresholds were 10 dB nHL across all frequencies, and median air-bone gaps were 0 dB across all frequencies. There was no significant threshold difference between left and right ears and no significant relationship between thresholds and hearing loss risk factors, ethnicity or gender. Older age was related to decreased latency for air conduction. Compared to previous studies, mean air conduction thresholds were found at slightly lower (better) levels, while bone conduction levels were better at 2000 Hz and higher at 500 Hz. Latency values were longer at 500 Hz than previous studies using other instrumentation. Sleep state did not affect air or bone conduction thresholds. Conclusions This study demonstrated slightly better Wave V thresholds for air conduction than previous infant studies. The differences found in the current study, while statistically significant, were within the test

  7. Performance testing of the AC propulsion ELX electric vehicle

    NASA Astrophysics Data System (ADS)

    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%.

  8. 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%.

  9. 47 CFR 15.107 - Conducted limits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the public utility (AC) power line, the radio frequency voltage that is conducted back onto the AC... device that is designed to be connected to the public utility (AC) power line, the radio frequency voltage that is conducted back onto the AC power line on any frequency or frequencies within the band...

  10. 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.

  11. Ionic Conductivity and Air Stability of Al-Doped Li₇La₃Zr₂O₁₂ Sintered in Alumina and Pt Crucibles.

    PubMed

    Xia, Wenhao; Xu, Biyi; Duan, Huanan; Guo, Yiping; Kang, Hongmei; Li, Hua; Liu, Hezhou

    2016-03-01

    Li7La3Zr2O12 (LLZO) is a promising electrolyte material for all-solid-state battery due to its high ionic conductivity and good stability with metallic lithium. In this article, we studied the effect of crucibles on the ionic conductivity and air stability by synthesizing 0.25Al doped LLZO pellets in Pt crucibles and alumina crucibles, respectively. The results show that the composition and microstructure of the pellets play important roles influencing the ionic conductivity, relative density, and air stability. Specifically, the 0.25Al-LLZO pellets sintered in Pt crucibles exhibit a high relative density (∼96%) and high ionic conductivity (4.48 × 10(-4) S cm(-1)). The ionic conductivity maintains 3.6 × 10(-4) S cm(-1) after 3-month air exposure. In contrast, the ionic conductivity of the pellets from alumina crucibles is about 1.81 × 10(-4) S cm(-1) and drops to 2.39 × 10(-5) S cm(-1) 3 months later. The large grains and the reduced grain boundaries in the pellets sintered in Pt crucibles are favorable to obtain high ionic conductivity and good air stability. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy results suggest that the formation of Li2CO3 on the pellet surface is probably another main reason, which is also closely related to the relative density and the amount of grain boundary within the pellets. This work stresses the importance of synthesis parameters, crucibles included, to obtain the LLZO electrolyte with high ionic conductivity and good air stability.

  12. Water temperature effect on upward air-water flow in a vertical pipe: Local measurements database using four-sensor conductivity probes and LDA

    NASA Astrophysics Data System (ADS)

    Monrós-Andreu, G.; Chiva, S.; Martínez-Cuenca, R.; Torró, S.; Juliá, J. E.; Hernández, L.; Mondragón, R.

    2013-04-01

    Experimental work was carried out to study the effects of temperature variation in bubbly, bubbly to slug transition. Experiments were carried out in an upward air-water flow configuration. Four sensor conductivity probes and LDA techniques was used together for the measurement of bubble parameters. The aim of this paper is to provide a bubble parameter experimental database using four-sensor conductivity probes and LDA technique for upward air-water flow at different temperatures and also show transition effect in different temperatures under the boiling point.

  13. Synthesis of an air-working trilayer artificial muscle using a conductive cassava starch biofilm (manihot esculenta, cranz) and polypyrrole (PPy)

    NASA Astrophysics Data System (ADS)

    Núñez D, Y. E.; Arrieta A, Á. A.; Segura B, J. A.; Bertel H, S. D.

    2016-02-01

    In this study, a methodology for obtaining a conductive cassava starch biofilm doped with lithium perchlorate (LiClO4) is shown, as well as the electrochemical technique for the synthesis of polypyrrole films, which are used for developing the trilayer artificial muscle PPy/Biopolymer/PPy designed to operate in air. Furthermore, results from the trilayer movement using chronoamperometric techniques are shown.

  14. Control of Photosynthesis and Stomatal Conductance in Ricinus communis L. (Castor Bean) by Leaf to Air Vapor Pressure Deficit.

    PubMed

    Dai, Z; Edwards, G E; Ku, M S

    1992-08-01

    Castor bean (Ricinus communis L.) has a high photosynthetic capacity under high humidity and a pronounced sensitivity of photosynthesis to high water vapor pressure deficit (VPD). The sensitivity of photosynthesis to varying VPD was analyzed by measuring CO(2) assimilation, stomatal conductance (g(s)), quantum yield of photosystem II (phi(II)), and nonphotochemical quenching of chlorophyll fluorescence (q(N)) under different VPD. Under both medium (1000) and high (1800 micromoles quanta per square meter per second) light intensities, CO(2) assimilation decreased as the VPD between the leaf and the air around the leaf increased. The g(s) initially dropped rapidly with increasing VPD and then showed a slower decrease above a VPD of 10 to 20 millibars. Over a temperature range from 20 to 40 degrees C, CO(2) assimilation and g(s) were inhibited by high VPD (20 millibars). However, the rate of transpiration increased with increasing temperature at either low or high VPD due to an increase in g(s). The relative inhibition of photosynthesis under photorespiring (atmospheric levels of CO(2) and O(2)) versus nonphotorespiring (700 microbars CO(2) and 2% O(2)) conditions was greater under high VPD (30 millibars) than under low VPD (3 millibars). Also, with increasing light intensity the relative inhibition of photosynthesis by O(2) increased under high VPD, but decreased under low VPD. The effect of high VPD on photosynthesis under various conditions could not be totally accounted for by the decrease in the intercellular CO(2) in the leaf (C(i)) where C(i) was estimated from gas exchange measurements. However, estimates of C(i) from measurements of phi(II) and q(N) suggest that the decrease in photosynthesis and increase in photorespiration under high VPD can be totally accounted for by stomatal closure and a decrease in C(i). The results also suggest that nonuniform closure of stomata may occur in well-watered plants under high VPD, causing overestimates in the calculation

  15. Analyses and estimates of hydraulic conductivity from slug tests in alluvial aquifer underlying Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

    USGS Publications Warehouse

    Houston, Natalie A.; Braun, Christopher L.

    2004-01-01

    This report describes the collection, analyses, and distribution of hydraulic-conductivity data obtained from slug tests completed in the alluvial aquifer underlying Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas, during October 2002 and August 2003 and summarizes previously available hydraulic-conductivity data. The U.S. Geological Survey, in cooperation with the U.S. Air Force, completed 30 slug tests in October 2002 and August 2003 to obtain estimates of horizontal hydraulic conductivity to use as initial values in a ground-water-flow model for the site. The tests were done by placing a polyvinyl-chloride slug of known volume beneath the water level in selected wells, removing the slug, and measuring the resulting water-level recovery over time. The water levels were measured with a pressure transducer and recorded with a data logger. Hydraulic-conductivity values were estimated from an analytical relation between the instantaneous displacement of water in a well bore and the resulting rate of head change. Although nearly two-thirds of the tested wells recovered 90 percent of their slug-induced head change in less than 2 minutes, 90-percent recovery times ranged from 3 seconds to 35 minutes. The estimates of hydraulic conductivity range from 0.2 to 200 feet per day. Eighty-three percent of the estimates are between 1 and 100 feet per day.

  16. The relation between temperature distribution for lung RFA and electromagnetic wave frequency dependence of electrical conductivity with changing a lung's internal air volumes.

    PubMed

    Yamazaki, Nozomu; Watanabe, Hiroki; Lu, Xiaowei; Isobe, Yosuke; Kobayashi, Yo; Miyashita, Tomoyuki; Fujie, Masakatsu G

    2013-01-01

    Radio frequency ablation (RFA) for lung cancer has increasingly been used over the past few years because it is a minimally invasive treatment. As a feature of RFA for lung cancer, lung contains air during operation. Air is low thermal and electrical conductivity. Therefore, RFA for this cancer has the advantage that only the cancer is coagulated, and it is difficult for operators to control the precise formation of coagulation lesion. In order to overcome this limitation, we previously proposed a model-based robotic ablation system using finite element method. Creating an accurate thermo physical model and constructing thermal control method were a challenging problem because the thermal properties of the organ are complex. In this study, we measured electromagnetic wave frequency dependence of lung's electrical conductivity that was based on lung's internal air volumes dependence with in vitro experiment. In addition, we validated the electromagnetic wave frequency dependence of lung's electrical conductivity using temperature distribution simulator. From the results of this study, it is confirmed that the electromagnetic wave frequency dependence of lung's electrical conductivity effects on heat generation of RFA.

  17. AIR POLLUTION MEASUREMENTS IN THE VICINITY OF THE WORLD TRADE CENTER - SUMMARY OF MEASUREMENTS CONDUCTED BY EPA-ORD

    EPA Science Inventory

    The U.S. Environmental Protection Agency's Office of Research and Development (EPA-ORD) was requested by EPA's Region 2 office in New York on 9/12/01 to assist with air quality monitoring in response to the collapse of the World Trade Center. Scientists at the U.S. EPA-ORD's Nati...

  18. Leaf conductance decreased under free-air CO2 enrichment (FACE) for three perennials in the Nevada desert

    USGS Publications Warehouse

    Nowak, Robert S.; Defalco, Lesley A.; Wilcox, Carolyn S.; Jordan, Dean N.; Coleman, James S.; Seemann, Jeffrey R.; Smith, Stanley D.

    2001-01-01

    A common response of plants to elevated atmospheric CO2 concentration (CO2) is decreased leaf conductance. Consequently, leaf temperature is predicted to increase under elevated CO2.Diurnal patterns of leaf conductance and temperature were measured for three desert perennials, the C3 shrub Larrea tridentata, C3 tussock grass Achnatherum hymenoides and C4tussock grass Pleuraphis rigida, at the Nevada Desert FACE facility. Measurements were made on ambient and c. 550 µmol mol−1 CO2 plots through both a wet and dry year.Reductions in conductance were 35%, 20% and 13% for Pleuraphis, Achnatherum and Larrea, respectively. Decreased conductance occurred throughout the day only for Pleuraphis. Both C3species had smaller CO2 effects during dry periods than wet. Leaf temperature did not differ significantly between elevated and ambient CO2 for any species. Comparisons of blower-control and nonring plots indicated that the FACE apparatus did not confound our results.All three species exhibited decreased leaf conductance under elevated CO2, although reductions were not uniform during the day or among years. Nonetheless, leaf energy balance was only minimally changed for these microphyllous desert perennials.

  19. Horizontal coring using air as the circulating fluid: Some prototype studies conducted in G Tunnel at the Nevada Test Site for the Yucca Mountain Project

    SciTech Connect

    Chornack, M.P.; French, C.A.

    1989-12-31

    Horizontal coring using air as the circulating fluid has been conducted in the G Tunnel Underground Facility (GTUF) at the Nevada Test Site. This work is part of the prototype investigations of hydrogeology for the Yucca Mountain Project. The work is being conducted to develop methods and procedures that will be used at the Department of Energy`s Yucca Mountain Site, a candidate site for the nation`s first high-level nuclear waste repository, during the site characterization phase of the investigations. The United States Geological Survey (USGS) is conducting this prototype testing under the guidance of the Los Alamos National Laboratory (LANL) and in conjunction with Reynolds Electrical & Engineering Company (REECo), the drilling contractor. 7 refs., 8 figs., 5 tabs.

  20. 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.

  1. A perovskite oxide with high conductivities in both air and reducing atmosphere for use as electrode for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Lan, Rong; Cowin, Peter I.; Sengodan, Sivaprakash; Tao, Shanwen

    2016-08-01

    Electrode materials which exhibit high conductivities in both oxidising and reducing atmospheres are in high demand for solid oxide fuel cells (SOFCs) and solid oxide electrolytic cells (SOECs). In this paper, we investigated Cu-doped SrFe0.9Nb0.1O3‑δ finding that the primitive perovskite oxide SrFe0.8Cu0.1Nb0.1O3‑δ (SFCN) exhibits a conductivity of 63 Scm‑1and 60 Scm‑1 at 415 °C in air and 5%H2/Ar respectively. It is believed that the high conductivity in 5%H2/Ar is related to the exsolved Fe (or FeCu alloy) on exposure to a reducing atmosphere. To the best of our knowledge, the conductivity of SrFe0.8Cu0.1Nb0.1O3‑δ in a reducing atmosphere is the highest of all reported oxides which also exhibit a high conductivity in air. Fuel cell performance using SrFe0.8Cu0.1Nb0.1O3‑δ as the anode, (Y2O3)0.08(ZrO2)0.92 as the electrolyte and La0.8Sr0.2FeO3‑δ as the cathode achieved a power density of 423 mWcm‑2 at 700 °C indicating that SFCN is a promising anode for SOFCs.

  2. A perovskite oxide with high conductivities in both air and reducing atmosphere for use as electrode for solid oxide fuel cells.

    PubMed

    Lan, Rong; Cowin, Peter I; Sengodan, Sivaprakash; Tao, Shanwen

    2016-08-22

    Electrode materials which exhibit high conductivities in both oxidising and reducing atmospheres are in high demand for solid oxide fuel cells (SOFCs) and solid oxide electrolytic cells (SOECs). In this paper, we investigated Cu-doped SrFe0.9Nb0.1O3-δ finding that the primitive perovskite oxide SrFe0.8Cu0.1Nb0.1O3-δ (SFCN) exhibits a conductivity of 63 Scm(-1)and 60 Scm(-1) at 415 °C in air and 5%H2/Ar respectively. It is believed that the high conductivity in 5%H2/Ar is related to the exsolved Fe (or FeCu alloy) on exposure to a reducing atmosphere. To the best of our knowledge, the conductivity of SrFe0.8Cu0.1Nb0.1O3-δ in a reducing atmosphere is the highest of all reported oxides which also exhibit a high conductivity in air. Fuel cell performance using SrFe0.8Cu0.1Nb0.1O3-δ as the anode, (Y2O3)0.08(ZrO2)0.92 as the electrolyte and La0.8Sr0.2FeO3-δ as the cathode achieved a power density of 423 mWcm(-2) at 700 °C indicating that SFCN is a promising anode for SOFCs.

  3. A perovskite oxide with high conductivities in both air and reducing atmosphere for use as electrode for solid oxide fuel cells

    PubMed Central

    Lan, Rong; Cowin, Peter I.; Sengodan, Sivaprakash; Tao, Shanwen

    2016-01-01

    Electrode materials which exhibit high conductivities in both oxidising and reducing atmospheres are in high demand for solid oxide fuel cells (SOFCs) and solid oxide electrolytic cells (SOECs). In this paper, we investigated Cu-doped SrFe0.9Nb0.1O3−δ finding that the primitive perovskite oxide SrFe0.8Cu0.1Nb0.1O3−δ (SFCN) exhibits a conductivity of 63 Scm−1and 60 Scm−1 at 415 °C in air and 5%H2/Ar respectively. It is believed that the high conductivity in 5%H2/Ar is related to the exsolved Fe (or FeCu alloy) on exposure to a reducing atmosphere. To the best of our knowledge, the conductivity of SrFe0.8Cu0.1Nb0.1O3−δ in a reducing atmosphere is the highest of all reported oxides which also exhibit a high conductivity in air. Fuel cell performance using SrFe0.8Cu0.1Nb0.1O3−δ as the anode, (Y2O3)0.08(ZrO2)0.92 as the electrolyte and La0.8Sr0.2FeO3−δ as the cathode achieved a power density of 423 mWcm−2 at 700 °C indicating that SFCN is a promising anode for SOFCs. PMID:27545200

  4. Study on lithium/air secondary batteries-Stability of NASICON-type lithium ion conducting glass-ceramics with water

    NASA Astrophysics Data System (ADS)

    Hasegawa, Satoshi; Imanishi, Nobuyuki; Zhang, Tao; Xie, Jian; Hirano, Atsushi; Takeda, Yasuo; Yamamoto, Osamu

    The water stability of the fast lithium ion conducting glass-ceramic electrolyte, Li 1+ x+ yAl xTi 2- xSi yP 3- yO 12 (LATP), has been examined in distilled water, and aqueous solutions of LiNO 3, LiCl, LiOH, and HCl. This glass-ceramics are stable in aqueous LiNO 3 and aqueous LiCl, and unstable in aqueous 0.1 M HCl and 1 M LiOH. In distilled water, the electrical conductivity slightly increases as a function of immersion time in water. The Li-Al/Li 3- xPO 4- yN y/LATP/aqueous 1 M LiCl/Pt cell, where lithium phosphors oxynitrides Li 3- xPO 4- yN y (LiPON) are used to protect the direct reaction of Li and LATP, shows a stable open circuit voltage (OCV) of 3.64 V at 25 °C, and no cell resistance change for 1 week. Lithium phosphors oxynitride is effectively used as a protective layer to suppress the reaction between the LATP and Li metal. The water-stable Li/LiPON/LATP system can be used in Li/air secondary batteries with the air electrode containing water.

  5. Leaf and canopy conductance in aspen and aspen-birch forests under free-air enrichment of carbon dioxide and ozone.

    PubMed

    Uddling, Johan; Teclaw, Ronald M; Pregitzer, Kurt S; Ellsworth, David S

    2009-11-01

    Increasing concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have the potential to affect tree physiology and structure, and hence forest feedbacks on climate. Here, we investigated how elevated concentrations of CO2 (+45%) and O3 (+35%), alone and in combination, affected conductance for mass transfer at the leaf and canopy levels in pure aspen (Populus tremuloides Michx.) and in mixed aspen and birch (Betula papyrifera Marsh.) forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). The study was conducted during two growing seasons, when steady-state leaf area index (L) had been reached after > 6 years of exposure to CO2- and O3-enrichment treatments. Canopy conductance (g(c)) was estimated from stand sap flux, while leaf-level conductance of sun leaves in the upper canopy was derived by three different and independent methods: sap flux and L in combination with vertical canopy modelling, leaf 13C discrimination methodology in combination with photosynthesis modelling and leaf-level gas exchange. Regardless of the method used, the mean values of leaf-level conductance were higher in trees growing under elevated CO2 and/or O3 than in trees growing in control plots, causing a CO2 x O3 interaction that was statistically significant (P < or = 0.10) for sap flux- and (for birch) 13C-derived leaf conductance. Canopy conductance was significantly increased by elevated CO2 but not significantly affected by elevated O3. Investigation of a short-term gap in CO2 enrichment demonstrated a +10% effect of transient exposure of elevated CO2-grown trees to ambient CO2 on g(c). All treatment effects were similar in pure aspen and mixed aspen-birch communities. These results demonstrate that short-term primary stomatal closure responses to elevated CO2 and O3 were completely offset by long-term cumulative effects of these trace gases on tree and stand structure in determining canopy- and leaf-level conductance in

  6. Leaf and canopy conductance in aspen and aspen-birch forests under free-air enrichment of carbon dioxide and ozone.

    PubMed

    Uddling, Johan; Teclaw, Ronald M; Pregitzer, Kurt S; Ellsworth, David S

    2009-11-01

    Increasing concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have the potential to affect tree physiology and structure, and hence forest feedbacks on climate. Here, we investigated how elevated concentrations of CO2 (+45%) and O3 (+35%), alone and in combination, affected conductance for mass transfer at the leaf and canopy levels in pure aspen (Populus tremuloides Michx.) and in mixed aspen and birch (Betula papyrifera Marsh.) forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). The study was conducted during two growing seasons, when steady-state leaf area index (L) had been reached after > 6 years of exposure to CO2- and O3-enrichment treatments. Canopy conductance (g(c)) was estimated from stand sap flux, while leaf-level conductance of sun leaves in the upper canopy was derived by three different and independent methods: sap flux and L in combination with vertical canopy modelling, leaf 13C discrimination methodology in combination with photosynthesis modelling and leaf-level gas exchange. Regardless of the method used, the mean values of leaf-level conductance were higher in trees growing under elevated CO2 and/or O3 than in trees growing in control plots, causing a CO2 x O3 interaction that was statistically significant (P < or = 0.10) for sap flux- and (for birch) 13C-derived leaf conductance. Canopy conductance was significantly increased by elevated CO2 but not significantly affected by elevated O3. Investigation of a short-term gap in CO2 enrichment demonstrated a +10% effect of transient exposure of elevated CO2-grown trees to ambient CO2 on g(c). All treatment effects were similar in pure aspen and mixed aspen-birch communities. These results demonstrate that short-term primary stomatal closure responses to elevated CO2 and O3 were completely offset by long-term cumulative effects of these trace gases on tree and stand structure in determining canopy- and leaf-level conductance in

  7. 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.

  8. 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.

  9. 47 CFR 15.207 - Conducted limits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... that is designed to be connected to the public utility (AC) power line, the radio frequency voltage that is conducted back onto the AC power line on any frequency or frequencies, within the band 150 kHz... for operation and which do not operate from the AC power lines or contain provisions for...

  10. How well do stomatal conductance models perform on closing plant carbon budgets? A test using seedlings grown under current and elevated air temperatures

    NASA Astrophysics Data System (ADS)

    Way, Danielle A.; Oren, Ram; Kim, Hyun-Seok; Katul, Gabriel G.

    2011-12-01

    Future carbon and water fluxes within terrestrial ecosystems will be determined by how stomatal conductance (gs) responds to rising atmospheric CO2and air temperatures. While both short- and long-term CO2 effects on gs have been repeatedly studied, there are few studies on how gs acclimates to higher air temperatures. Six gs models were parameterized using leaf gas exchange data from black spruce (Picea mariana) seedlings grown from seed at ambient (22/16°C day/night) or elevated (30/24°C) air temperatures. Model performance was independently assessed by how well carbon gain from each model reproduced estimated carbon costs to close the seedlings' seasonal carbon budgets, a `long-term' indicator of success. A model holding a constant intercellular to ambient CO2ratio and the Ball-Berry model (based on stomatal responses to relative humidity) could not close the carbon balance for either treatment, while the Jarvis-Oren model (based on stomatal responses to vapor pressure deficit,D) and a model assuming a constant gs each closed the carbon balance for one treatment. Two models, both based on gs responses to D, performed best overall, estimating carbon uptake within 10% of carbon costs for both treatments: the Leuning model and a linear optimization model that maximizes carbon gain per unit water loss. Since gsresponses in the optimization model are not a priori assumed, this approach can be used in modeling land-atmosphere exchange of CO2 and water in future climates.

  11. Conductivity Probe

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air.

    The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air.

    The needles on the probe are 15 millimeters (0.6 inch) long.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  12. 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.

  13. Isolation of sequences flanking Ac insertion sites by Ac casting.

    PubMed

    Wang, Dafang; Peterson, Thomas

    2013-01-01

    Localizing Ac insertions is a fundamental task in studying Ac-induced mutation and chromosomal rearrangements involving Ac elements. Researchers may sometimes be faced with the situation in which the sequence flanking one side of an Ac/Ds element is known, but the other flank is unknown. Or, a researcher may have a small sequence surrounding the Ac/Ds insertion site and needs to obtain additional flanking genomic sequences. One way to rapidly clone unknown Ac/Ds flanking sequences is via a PCR-based method termed Ac casting. This approach utilizes the somatic transposition activity of Ac during plant development, and provides an efficient means for short-range genome walking. Here we describe the principle of Ac casting, and show how it can be applied to isolate Ac macrotransposon insertion sites.

  14. Investigation of ULF magnetic pulsations, air conductivity changes, and infra red signatures associated with the 30 October Alum Rock M5.4 earthquake

    NASA Astrophysics Data System (ADS)

    Bleier, T.; Dunson, C.; Maniscalco, M.; Bryant, N.; Bambery, R.; Freund, F.

    2009-04-01

    Several electromagnetic signal types were observed prior to and immediately after 30 October 2007 (Local Time) M5.4 earthquake at Alum Rock, Ca with an epicenter ~15 km NE of San Jose Ca. The area where this event occurred had been monitored since November 2005 by a QuakeFinder magnetometer site, unit 609, 2 km from the epicenter. This instrument is one of 53 stations of the QuakeFinder (QF) California Magnetometer Network-CalMagNet. This station included an ultra low frequency (ULF) 3-axis induction magnetometer, a simple air conductivity sensor to measure relative airborne ion concentrations, and a geophone to identify the arrival of the P-wave from an earthquake. Similar in frequency content to the increased ULF activity reported two weeks prior to the Loma Prieta M7.0 quake in 1989 (Fraser-Smith, 1990, 1991), the QF station detected activity in the 0.01-12 Hz bands, but it consisted of an increasing number of short duration (1 to 30 s duration) pulsations. The pulsations peaked around 13 days prior to the event. The amplitudes of the pulses were strong, (3-20 nT), compared to the average ambient noise at the site, (10-250 pT), which included a component arising from the Bay Area Rapid Transit (BART) operations. The QF station also detected different pulse shapes, e.g. negative or positive only polarity, with some pulses including a combination of positive and negative. Typical pulse counts over the previous year ranged from 0-15 per day, while the count rose to 176 (east-west channel) on 17 October, 13 days prior to the quake. The air conductivity sensor saturated for over 14 h during the night and morning prior to the quake, which occurred at 20:29 LT. Anomalous IR signatures were also observed in the general area, within 50 km of the epicenter, during the 2 weeks prior to the quake. These three simultaneous EM phenomena were compared with data collected over a 1-2-year period at the site. The data was also compared against accounts of air ionization reported

  15. A study on lithium/air secondary batteries-Stability of the NASICON-type lithium ion conducting solid electrolyte in alkaline aqueous solutions

    NASA Astrophysics Data System (ADS)

    Shimonishi, Yuta; Zhang, Tao; Imanishi, Nobuyuki; Im, Dongmin; Lee, Dong Joon; Hirano, Atsushi; Takeda, Yasuo; Yamamoto, Osamu; Sammes, Nigel

    The stability of the high lithium ion conducting glass ceramics, Li 1+ x+ yTi 2- xAl xSi yP 3- yO 12 (LTAP) in alkaline aqueous solutions with and without LiCl has been examined. A significant conductivity decrease of the LTAP plate immersed in 0.057 M LiOH aqueous solution at 50 °C for 3 weeks was observed. However, no conductivity change of the LTAP plate immersed in LiCl saturated LiOH aqueous solutions at 50 °C for 3 weeks was observed. The pH value of the LiCl-LiOH-H 2O solution with saturated LiCl was in a range of 7-9. The molarity of LiOH and LiCl in the LiOH and LiCl saturated aqueous solution were estimated to be 5.12 and 11.57 M, respectively, by analysis of Li + and OH -. The high concentration of LiOH and the low pH value of 8.14 in this solution suggested that the dissociation of LiOH into Li + and OH - is too low in the solution with a high concentration of Li +. These results suggest that the water stable LTAP could be used as a protect layer of the lithium metal anode in the lithium/air cell with LiCl saturated aqueous solution as the electrolyte, because the content of OH - ions in the LiCl saturated aqueous solution does not increase via the cell reaction of Li + 1/2O 2 + H 2O → 2LiOH, and LTAP is stable under a deep discharge state.

  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. PMID:16351310

  17. How well do stomatal conductance models perform on closing plant carbon budgets? A test using seedlings grown under current and elevated air temperatures

    NASA Astrophysics Data System (ADS)

    Way, D.; Oren, R.; Kim, H.; Katul, G. G.

    2011-12-01

    Future carbon and water fluxes within terrestrial ecosystems will be determined by how stomatal conductance (gs) responds to rising atmospheric CO2 and air temperatures. While both short- and long-term CO2 effects on gs have been repeatedly studied, there are few studies on how gs acclimates to higher air temperatures. Six gs models were parameterized using leaf gas exchange data from black spruce (Picea mariana) seedlings grown from seed at ambient (22/16 °C day/night) or elevated (30/24 °C) temperatures. Model performance was independently assessed by how well carbon gain from each model reproduced estimated carbon costs to close the seedlings' seasonal carbon budgets, an indicator of the model success at time scales commensurate with biomass changes. A model holding a constant intercellular to ambient CO2 concentration ratio and the Ball-Berry model (based on stomatal responses to relative humidity) could not close the carbon balance for either treatment, while a so-called Jarvis-Oren model (based on stomatal responses to vapor pressure deficit, D) and a model assuming a constant gs each closed the carbon balance for one temperature treatment. Two models, both based on gs responses to D, performed best overall, estimating carbon uptake within 10% of carbon costs for both treatments: the Leuning model (a semi-empirical model that links gs to photosynthetic rates) and a linear optimization model that maximizes carbon gain per unit water loss. Since gs responses in the linear optimization model are not a priori assumed, this approach may be advantageous in modeling gs responses to temperature, especially in future climates.

  18. 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.

  19. AC-3 audio coder

    NASA Astrophysics Data System (ADS)

    Todd, Craig

    1995-12-01

    AC-3 is a system for coding up to 5.1 channels of audio into a low bit-rate data stream. High quality may be obtained with compression ratios approaching 12-1 for multichannel audio programs. The high compression ratio is achieved by methods which do not increase decoder memory, and thus cost. The methods employed include: the transmission of a high frequency resolution spectral envelope; and a novel forward/backward adaptive bit allocation algorithm. In order to satisfy practical requirements of an emissions coder, the AC-3 syntax includes a number of features useful to broadcasters and consumers. These features include: loudness uniformity between programs; dynamic range control; and broadcaster control of downmix coefficients. The AC-3 coder has been formally selected for inclusion of the U.S. HDTV broadcast standard, and has been informally selected for several additional applications.

  20. 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

  1. Air conditioning impact on the dynamics of radon and its daughters concentration.

    PubMed

    Kozak, Krzysztof; Grządziel, Dominik; Połednik, Bernard; Mazur, Jadwiga; Dudzińska, Marzenna R; Mroczek, Mariusz

    2014-12-01

    Radon and its decay products are harmful pollutants present in indoor air and are responsible for the majority of the effective dose due to ionising radiation that people are naturally exposed to. The paper presents the results of the series of measurements of radon and its progeny (in unattached and attached fractions) as well as indoor air parameters: temperature, relative humidity, number and mass concentrations of fine aerosol particles. The measurements were carried out in the auditorium (lecture hall), which is an indoor air quality laboratory, in controlled conditions during two periods of time: when air conditioning (AC) was switched off (unoccupied auditorium) and when it was switched on (auditorium in normal use). The significant influence of AC and of students' presence on the dynamics of radon and its progeny was confirmed. A decrease in the mean value of radon and its attached progeny was found when AC was working. The mean value of radon equilibrium factor F was also lower when AC was working (0.49) than when it was off (0.61). The linear correlations were found between attached radon progeny concentration and particle number and mass concentration only when the AC was switched off. This research is being conducted with the aim to study the variability of radon equilibrium factor F which is essential to determine the effective dose due to radon and its progeny inhalation.

  2. Air conditioning impact on the dynamics of radon and its daughters concentration.

    PubMed

    Kozak, Krzysztof; Grządziel, Dominik; Połednik, Bernard; Mazur, Jadwiga; Dudzińska, Marzenna R; Mroczek, Mariusz

    2014-12-01

    Radon and its decay products are harmful pollutants present in indoor air and are responsible for the majority of the effective dose due to ionising radiation that people are naturally exposed to. The paper presents the results of the series of measurements of radon and its progeny (in unattached and attached fractions) as well as indoor air parameters: temperature, relative humidity, number and mass concentrations of fine aerosol particles. The measurements were carried out in the auditorium (lecture hall), which is an indoor air quality laboratory, in controlled conditions during two periods of time: when air conditioning (AC) was switched off (unoccupied auditorium) and when it was switched on (auditorium in normal use). The significant influence of AC and of students' presence on the dynamics of radon and its progeny was confirmed. A decrease in the mean value of radon and its attached progeny was found when AC was working. The mean value of radon equilibrium factor F was also lower when AC was working (0.49) than when it was off (0.61). The linear correlations were found between attached radon progeny concentration and particle number and mass concentration only when the AC was switched off. This research is being conducted with the aim to study the variability of radon equilibrium factor F which is essential to determine the effective dose due to radon and its progeny inhalation. PMID:24375376

  3. 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.

  4. AC/RF Superconductivity

    SciTech Connect

    Ciovati, Gianluigi

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  5. Instrument sequentially samples ac signals from several accelerometers

    NASA Technical Reports Server (NTRS)

    Chapman, C. P.

    1967-01-01

    Scanner circuit sequentially samples the ac signals from accelerometers used in conducting noise vibration tests, and provides a time-averaged output signal. The scanner is used in conjunction with other devices for random noise vibration tests.

  6. AC plasma anemometer—characteristics and design

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    The characteristics and design of a high-bandwidth flow sensor that uses an AC glow discharge (plasma) as the sensing element is presented. The plasma forms in the air gap between two protruding low profile electrodes attached to a probe body. The output from the anemometer is an amplitude modulated version of the AC voltage input that contains information about the mean and fluctuating velocity components. The anemometer circuitry includes resistance and capacitance elements that simulate a dielectric-barrier to maintain a diffuse plasma, and a constant-current feedback control that maintains operation within the desired glow discharge regime over an extended range of air velocities. Mean velocity calibrations are demonstrated over a range from 0 to 140 m s-1. Over this velocity range, the mean output voltage varied linearly with air velocity, providing a constant static sensitivity. The effect of the electrode gap and input AC carrier frequency on the anemometer static sensitivity and dynamic response are investigated. Experiments are performed to compare measurements obtained with a plasma sensor operating at two AC carrier frequencies against that of a constant-temperature hot-wire. All three sensors were calibrated against the same known velocity reference. An uncertainty based on the standard deviation of the velocity calibration fit was applied to the mean and fluctuating velocity measurements of the three sensors. The motivation is not to replace hot-wires as a general measurement tool, but rather as an alternative to hot-wires in harsh environments or at high Mach numbers where they either have difficulty in surviving or lack the necessary frequency response.

  7. 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.

  8. Manipulating Flames with AC Electric Fields

    NASA Astrophysics Data System (ADS)

    Bishop, Kyle

    2013-11-01

    Time-oscillating electric fields applied to plasmas present in flames create steady flows of gas capable of shaping, directing, enhancing, or even extinguishing flames. Interestingly, electric winds induced by AC electric fields can be stronger that those due to static fields of comparable magnitude. Furthermore, unlike static fields, the electric force due to AC fields is localized near the surface of the flame. Consequently, the AC response depends only on the local field at the surface of the flame - not on the position of the electrodes used to generate the field. These results suggest that oscillating electric fields can be used to manipulate and control combustion processes at a distance. To characterize and explain these effects, we investigate a simple experimental system comprising a laminar methane-air flame positioned between two parallel-plate electrodes. We quantify both the electric and hydrodynamic response of the flame as a function of frequency and magnitude of the applied field. A theoretical model shows how steady gas flows emerge from the time-averaged electrical force due to the field-induced motion of ions generated within the flame and by their disappearance by recombination. These results provide useful insights into the application of AC fields to direct combustion processes.

  9. Optimizing Stimulus Repetition Rate for Recording Ocular Vestibular Evoked Myogenic Potential Elicited by Air-Conduction Tone Bursts of 500 Hz

    PubMed Central

    Singh, Niraj Kumar; Kadisonga, Peter; Ashitha, Palliyath

    2014-01-01

    Amidst several publications reporting the effects of stimulus-related parameters on ocular vestibular evoked myogenic potential (oVEMP), the effect of the repetition rate on oVEMP responses has largely gone unexplored. Studies have used a repetition rate of ~5.1 Hz mainly due to a presumption that oVEMP, like cervical VEMP, should produce best responses for ~5 Hz, although there is paucity of experimental evidence to support this hypothesis. 52 healthy individuals in the age range of 17-35 years underwent air-conduction oVEMP elicited by 500 Hz tone-bursts using seven different repetition rates (3.1, 5.1, 10.1, 15.1, 20.1, 25.1 and 30.1 Hz). The results revealed a tendency for prolongation of latencies and reduction in amplitude with increasing repetition rate. However, significantly longer latencies were observed only for 20.1 Hz and larger amplitudes for 3.1 and 5.1 Hz (P<0.05). There was no significant difference between the rates of 3.1 Hz and 5.1 Hz. However 3.1 Hz produced poorer signal-to-noise ratio and required considerably longer time and thereby had lesser efficiency than 5.1 Hz (P<0.05). This would also result in higher fatigue and irritation levels considering the physical act of maintaining a supero-medial gaze. Thus the use of 5.1 Hz is recommended for clinical recording of oVEMP. PMID:26557349

  10. Effect of fee-for-service air-conditioning management in balancing thermal comfort and energy usage.

    PubMed

    Chen, Chen-Peng; Hwang, Ruey-Lung; Shih, Wen-Mei

    2014-11-01

    Balancing thermal comfort with the requirement of energy conservation presents a challenge in hot and humid areas where air-conditioning (AC) is frequently used in cooling indoor air. A field survey was conducted in Taiwan to demonstrate the adaptive behaviors of occupants in relation to the use of fans and AC in a school building employing mixed-mode ventilation where AC use was managed under a fee-for-service mechanism. The patterns of using windows, fans, and AC as well as the perceptions of students toward the thermal environment were examined. The results of thermal perception evaluation in relation to the indoor thermal conditions were compared to the levels of thermal comfort predicted by the adaptive models described in the American Society of Heating, Refrigerating, and Air-Conditioning Engineers Standard 55 and EN 15251 and to that of a local model for evaluating thermal adaption in naturally ventilated buildings. A thermal comfort-driven adaptive behavior model was established to illustrate the probability of fans/AC use at specific temperature and compared to the temperature threshold approach to illustrate the potential energy saving the fee-for-service mechanism provided. The findings of this study may be applied as a reference for regulating the operation of AC in school buildings of subtropical regions.

  11. Effect of fee-for-service air-conditioning management in balancing thermal comfort and energy usage

    NASA Astrophysics Data System (ADS)

    Chen, Chen-Peng; Hwang, Ruey-Lung; Shih, Wen-Mei

    2014-02-01

    Balancing thermal comfort with the requirement of energy conservation presents a challenge in hot and humid areas where air-conditioning (AC) is frequently used in cooling indoor air. A field survey was conducted in Taiwan to demonstrate the adaptive behaviors of occupants in relation to the use of fans and AC in a school building employing mixed-mode ventilation where AC use was managed under a fee-for-service mechanism. The patterns of using windows, fans, and AC as well as the perceptions of students toward the thermal environment were examined. The results of thermal perception evaluation in relation to the indoor thermal conditions were compared to the levels of thermal comfort predicted by the adaptive models described in the American Society of Heating, Refrigerating, and Air-Conditioning Engineers Standard 55 and EN 15251 and to that of a local model for evaluating thermal adaption in naturally ventilated buildings. A thermal comfort-driven adaptive behavior model was established to illustrate the probability of fans/AC use at specific temperature and compared to the temperature threshold approach to illustrate the potential energy saving the fee-for-service mechanism provided. The findings of this study may be applied as a reference for regulating the operation of AC in school buildings of subtropical regions.

  12. A Review and Analysis of Remote Sensing Capability for Air Quality Measurements as a Potential Decision Support Tool Conducted by the NASA DEVELOP Program

    NASA Technical Reports Server (NTRS)

    Ross, A.; Richards, A.; Keith, K.; Frew, C.; Boseck, J.; Sutton, S.; Watts, C.; Rickman, D.

    2007-01-01

    This project focused on a comprehensive utilization of air quality model products as decision support tools (DST) needed for public health applications. A review of past and future air quality measurement methods and their uncertainty, along with the relationship of air quality to national and global public health, is vital. This project described current and future NASA satellite remote sensing and ground sensing capabilities and the potential for using these sensors to enhance the prediction, prevention, and control of public health effects that result from poor air quality. The qualitative uncertainty of current satellite remotely sensed air quality, the ground-based remotely sensed air quality, the air quality/public health model, and the decision making process is evaluated in this study. Current peer-reviewed literature suggests that remotely sensed air quality parameters correlate well with ground-based sensor data. A satellite remote-sensed and ground-sensed data complement is needed to enhance the models/tools used by policy makers for the protection of national and global public health communities

  13. Air and Bone Conduction Thresholds of Deaf and Normal Hearing Subjects before and during the Elimination of Cutaneous-Tactile Interference with Anesthesia. Final Report.

    ERIC Educational Resources Information Center

    Nober, E. Harris

    The study investigated whether low frequency air and bone thresholds elicited at high intensity levels from deaf children with a sensory-neural diagnosis reflect valid auditory sensitivity or are mediated through cutaneous-tactile receptors. Subjects were five totally deaf (mean age 17.0) yielding vibrotactile thresholds but with no air and bone…

  14. AC power systems handbook

    SciTech Connect

    Whitaker, J.

    1991-01-01

    Transient disturbances are what headaches are made of. Whatever you call them-spikes, surges, are power bumps-they can take your equipment down and leave you with a complicated and expensive repair job. Protection against transient disturbances is a science that demands attention to detail. This book explains how the power distribution system works, what can go wrong with it, and how to protect a facility against abnormalities. system grounding and shielding are covered in detail. Each major method of transient protection is analyzed and its relative merits discussed. The book provides a complete look at the critical elements of the ac power system. Provides a complete look at the ac power system from generation to consumption. Discusses the mechanisms that produce transient disturbances and how to protect against them. Presents diagrams to facilitate system design. Covers new areas, such as the extent of the transient disturbance problem, transient protection options, and stand-by power systems.

  15. Increased Ac excision (iae): Arabidopsis thaliana mutations affecting Ac transposition.

    PubMed

    Jarvis, P; Belzile, F; Page, T; Dean, C

    1997-05-01

    The maize transposable element Ac is highly active in the heterologous hosts tobacco and tomato, but shows very much reduced levels of activity in Arabidopsis. A mutagenesis experiment was undertaken with the aim of identifying Arabidopsis host factors responsible for the observed low levels of Ac activity. Seed from a line carrying a single copy of the Ac element inserted into the streptomycin phosphotransferase (SPT) reporter fusion, and which displayed typically low levels of Ac activity, were mutagenized using gamma rays. Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium. The mutations fall into two complementation groups, iae1 and iae2, are unlinked to the SPT::Ac locus and segregate in a Mendelian fashion. The iae1 mutation is recessive and the iae2 mutation is semi-dominant. The iae1 and iae2 mutants show 550- and 70-fold increases, respectively, in the average number of Ac excision sectors per cotyledon. The IAE1 locus maps to chromosome 2, whereas the SPT::Ac reporter maps to chromosome 3. A molecular study of Ac activity in the iae1 mutant confirmed the very high levels of Ac excision predicted using the phenotypic assay, but revealed only low levels of Ac re-insertion. Analyses of germinal transposition in the iae1 mutant demonstrated an average germinal excision frequency of 3% and a frequency of independent Ac re-insertions following germinal excision of 22%. The iae mutants represents a possible means of improving the efficiency of Ac/Ds transposon tagging systems in Arabidopsis, and will enable the dissection of host involvement in Ac transposition and the mechanisms employed for controlling transposable element activity.

  16. RHIC AC DIPOLE DESIGN AND CONSTRUCTION.

    SciTech Connect

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

    2001-06-18

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

  17. Tennessee Valley Authority/Bonneville Power Administration Indoor Air Quality Study, Phase II : Final Report for Indoor Air Quality Studies Conducted by TVA During Winters 1983, 1984, and 1985.

    SciTech Connect

    Tennessee Valley Authority. Energy Use Test Facility Staff.

    1985-12-01

    This study expanded the existing data base on indoor-outdoor air quality and provided specific information on the use of wood-burning heaters in a weatherized home having a low air exchange rate. Through research efforts such as these, BPA continues to address the various concerns raised regarding environmental issues related to its conservtion programs.

  18. 75 FR 60493 - Advisory Circular 120-79A, Developing and Implementing an Air Carrier Continuing Analysis and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-30

    ... (AC) 120-79A, ``Developing and Implementing an Air Carrier Continuing Analysis and Surveillance System''. This new advisory circular (AC) updates AC 120-79 originally issued on April 21, 2003. This new AC... . SUPPLEMENTARY INFORMATION: How To Obtain Copies: You can read or download this AC from the Internet at...

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. AC and DC power transmission

    SciTech Connect

    Not Available

    1985-01-01

    The technical and economic assessment of AC and DC transmission systems; long distance transmission, cable transmission, system inter-connection, voltage support, reactive compensation, stabilisation of systems; parallel operation of DC links with AC systems; comparison between alternatives for particular schemes. Design and application equipment: design, testing and application of equipment for HVDC, series and shunt static compensated AC schemes, including associated controls. Installations: overall design of stations and conductor arrangements for HVDC, series and shunt static AC schemes including insulation co-ordination. System analysis and modelling.

  4. DETAIL OF HEATING/COOLING SYSTEM, A/C MECHANICAL EQUIPMENT ROOM, FACING NORTHEAST ...

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

    DETAIL OF HEATING/COOLING SYSTEM, A/C MECHANICAL EQUIPMENT ROOM, FACING NORTHEAST - Cape Canaveral Air Force Station, Launch Complex 34, Operations Support Building, Freedom Road, Southwest of Launch Stand CX-34, Cape Canaveral, Brevard County, FL

  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. 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.

  7. Preparation of a new adsorbent from activated carbon and carbon nanofiber (AC/CNF) for manufacturing organic-vacbpour respirator cartridge.

    PubMed

    Jahangiri, Mehdi; Adl, Javad; Shahtaheri, Seyyed Jamaleddin; Rashidi, Alimorad; Ghorbanali, Amir; Kakooe, Hossein; Forushani, Abbas Rahimi; Ganjali, Mohammad Reza

    2013-01-26

    In this study a composite of activated carbon and carbon nanofiber (AC/CNF) was prepared to improve the performance of activated carbon (AC) for adsorption of volatile organic compounds (VOCs) and its utilization for respirator cartridges. Activated carbon was impregnated with a nickel nitrate catalyst precursor and carbon nanofibers (CNF) were deposited directly on the AC surface using catalytic chemical vapor deposition. Deposited CNFs on catalyst particles in AC micropores, were activated by CO2 to recover the surface area and micropores. Surface and textural characterizations of the prepared composites were investigated using Brunauer, Emmett and Teller's (BET) technique and electron microscopy respectively. Prepared composite adsorbent was tested for benzene, toluene and xylene (BTX) adsorption and then employed in an organic respirator cartridge in granular form. Adsorption studies were conducted by passing air samples through the adsorbents in a glass column at an adjustable flow rate. Finally, any adsorbed species not retained by the adsorbents in the column were trapped in a charcoal sorbent tube and analyzed by gas chromatography. CNFs with a very thin diameter of about 10-20 nm were formed uniformly on the AC/CNF. The breakthrough time for cartridges prepared with CO2 activated AC/CNF was 117 minutes which are significantly longer than for those cartridges prepared with walnut shell- based activated carbon with the same weight of adsorbents. This study showed that a granular form CO2 activated AC/CNF composite could be a very effective alternate adsorbent for respirator cartridges due to its larger adsorption capacities and lower weight.

  8. Preparation of a new adsorbent from activated carbon and carbon nanofiber (AC/CNF) for manufacturing organic-vacbpour respirator cartridge

    PubMed Central

    2013-01-01

    In this study a composite of activated carbon and carbon nanofiber (AC/CNF) was prepared to improve the performance of activated carbon (AC) for adsorption of volatile organic compounds (VOCs) and its utilization for respirator cartridges. Activated carbon was impregnated with a nickel nitrate catalyst precursor and carbon nanofibers (CNF) were deposited directly on the AC surface using catalytic chemical vapor deposition. Deposited CNFs on catalyst particles in AC micropores, were activated by CO2 to recover the surface area and micropores. Surface and textural characterizations of the prepared composites were investigated using Brunauer, Emmett and Teller’s (BET) technique and electron microscopy respectively. Prepared composite adsorbent was tested for benzene, toluene and xylene (BTX) adsorption and then employed in an organic respirator cartridge in granular form. Adsorption studies were conducted by passing air samples through the adsorbents in a glass column at an adjustable flow rate. Finally, any adsorbed species not retained by the adsorbents in the column were trapped in a charcoal sorbent tube and analyzed by gas chromatography. CNFs with a very thin diameter of about 10-20 nm were formed uniformly on the AC/CNF. The breakthrough time for cartridges prepared with CO2 activated AC/CNF was 117 minutes which are significantly longer than for those cartridges prepared with walnut shell- based activated carbon with the same weight of adsorbents. This study showed that a granular form CO2 activated AC/CNF composite could be a very effective alternate adsorbent for respirator cartridges due to its larger adsorption capacities and lower weight. PMID:23369424

  9. Testing the equation of state and electrical conductivity of copper by the electrical wire explosion in air: Experiment and magnetohydrodynamic simulation

    SciTech Connect

    Barysevich, A. E.; Cherkas, S. L.

    2011-05-15

    We perform experiments on testing the equations of state and electrical conductivity of copper in three different regimes of copper wire electrical explosion, when the inserted energy (i) is slightly exceeded, (ii) is approximately equal, and (iii) is substantially exceeded the energy needed for the wire complete evaporation. Magnetohydrodynamic simulation is performed. The results predicted by the two different equations of state are compared with the experiment. Empirical expression for the copper electrical conductivity is presented. Parameters in this expression is fit on every of two equations of state. Map of copper conductivity is plotted.

  10. AC 95 - selected readings

    SciTech Connect

    1995-12-31

    Reports are presented on energy efficiency and conservation in residential buildings. Topics include housing and energy linkages; the people factor; low-income initiatives; green visions; utility programs; affordable comfort; housing as a system; and pressures and air flow in buildings.

  11. Evidence of inner ear contribution in bone conduction in chinchilla.

    PubMed

    Chhan, David; Röösli, Christof; McKinnon, Melissa L; Rosowski, John J

    2013-07-01

    We investigated the contribution of the middle ear to the physiological response to bone conduction stimuli in chinchilla. We measured intracochlear sound pressure in response to air conduction (AC) and bone conduction (BC) stimuli before and after interruption of the ossicular chain at the incudo-stapedial joint. Interruption of the chain effectively decouples the external and middle ear from the inner ear and significantly reduces the contributions of the outer ear and middle ear to the bone conduction response. With AC stimulation, both the scala vestibuli Psv and scala tympani Pst sound pressures drop by 30-40 dB after the interruption. In BC stimulation, Psv decreases after interruption by about 10-20 dB, but Pst is little affected. This difference in the sensitivity of the BC induced Psv and Pst to ossicular interruption is not consistent with a BC response to ossicular motion, but instead suggests a significant contribution of an inner-ear drive (e.g., cochlear fluid inertia or compressibility) to the BC response. This article is part of a special issue entitled "MEMRO 2012".

  12. Evidence of Inner Ear Contribution in Bone Conduction in Chinchilla

    PubMed Central

    Chhan, David; Roosli, Christof; McKinnon, Melissa L.; Rosowski, John J.

    2013-01-01

    We investigated the contribution of the middle ear to the physiological response to bone conduction stimuli in chinchilla. We measured intracochlear sound pressure in response to air conduction (AC) and bone conduction (BC) stimuli before and after interruption of the ossicular chain at the incudo-stapedial joint. Interruption of the chain effectively decouples the external and middle ear from the inner ear and significantly reduces the contributions of the outer ear and middle ear to the bone conduction response. With AC stimulation, both the scala vestibuli Psv and scala tympani Pst sound pressures drop by 30 to 40 dB after the interruption. In BC stimulation, Psv decreases after interruption by about 10 to 20 dB, but Pst is little affected. This difference in the sensitivity of the BC induced Psv and Pst to ossicular interruption is not consistent with a BC response to ossicular motion, but instead suggests a significant contribution of an inner-ear drive (e.g. cochlear fluid inertia or compressibility) to the BC response. PMID:23211609

  13. Effect of air-conditioner on fungal contamination

    NASA Astrophysics Data System (ADS)

    Hamada, Nobuo; Fujita, Tadao

    Air-conditioners (AC) produce much dew and wet conditions inside their apparatus, when in operation. We studied the fungal contamination in AC and found that the average fungal contamination of AC filters was about 5-fold greater than that of a carpet, and Cladosporium and Penicillium were predominant in AC filters. The fungal contamination inside AC, which were used everyday, increased more markedly than those not used daily, e.g. a few days per week or rarely. Moreover, the airborne fungal contamination in rooms during air-conditioning was about 2-fold greater than one in rooms without AC, and was highest when air-conditioning started and decreased gradually with time. We recognized that the airborne fungal contamination was controlled by the environmental condition of the rooms, in which AC were used. It is suggested that AC might promote mold allergies in users via airborne fungal spores derived from the AC. On the other hand, AC was estimated to remove moisture in the room atmosphere and carpets, and reduce the relative humidity in rooms. It was found that the average fungal contamination in the house dust of carpets with AC was suppressed by two-third of that in rooms without AC. The use of AC for suppressing fungal hazards was discussed.

  14. Thermal conditions and perceived air quality in an air-conditioned auditorium

    NASA Astrophysics Data System (ADS)

    Polednik, Bernard; Guz, Łukasz; Skwarczyński, Mariusz; Dudzińska, Marzenna R.

    2016-07-01

    The study reports measurements of indoor air temperature (T) and relative humidity (RH), perceived air quality (PAQ) and CO2, fine aerosol particle number (PN) and mass (PM1) concentrations in an air conditioned auditorium. The measurements of these air physical parameters have been carried out in the unoccupied auditorium with the air conditioning system switched off (AC off mode) and in the unoccupied and occupied auditorium with the air conditioning system switched off during the night and switched on during the day (AC on/off mode). The average indoor air thermal parameters, CO2 concentration and the PAQ value (in decipols) were elevated, while average PM1 concentration was lower in the AC on/off mode. A statistically significant (p < 0.001) positive correlation has been observed between T and PAQ values and CO2 concentrations (r = 0.66 and r = 0.59, respectively) in that AC mode. A significant negative correlation has been observed between T and PN and PM1 concentrations (r = -0.38 and r = -0.49, respectively). In the AC off mode the above relations between T and the particle concentrations were not that unequivocal. These findings may be of importance as they indicate that in certain AC operation modes the indoor air quality deteriorates along with the variation of the indoor air microclimate and room occupation. This, in turn, may adversely affect the comfort and productivity of the users of air conditioned premises.

  15. Use of air-pressurized slug tests to estimate hydraulic conductivity at selected piezometers completed in the Santa Fe Group aquifer system, Albuquerque area, New Mexico

    USGS Publications Warehouse

    Thomas, Carole L.; Thorn, Conde R.

    2000-01-01

    The City of Albuquerque Public Works Department, Water Resources Management (City), is interested in quantifying aquifer hydraulic properties in the Albuquerque, New Mexico, area to better understand and manage water resources in the Middle Rio Grande Basin. In 1998, the City and the U.S. Geological Survey entered into a cooperative program to determine hydraulic properties of aquifer material adjacent to screened intervals of piezometers in the Albuquerque area. Investigators conducted slug tests from March 8 through April 8, 1999, to estimate hydraulic conductivity of aquifer material adjacent to the screened intervals of 25 piezometers from 11 nested- piezometer sites in the Albuquerque area. At 20 of the piezometers, slug-test responses were typical; at 2 piezometers, tests were prematurely terminated because the tests were taking too long to complete; and at 3 piezometers, test responses were oscillatory. Methods used to estimate hydraulic conductivity were the Bouwer and Rice method or the Cooper, Bredehoeft, and Papadopulos method for most tests; the Shapiro and Greene method for prematurely terminated tests; and the van der Kamp method for oscillatory tests. Hydraulic-conductivity estimates ranged from about 0.15 to 92 feet per day. In general, the smaller estimated values are associated with fine-grained aquifer materials and the larger estimated hydraulic-conductivity values are associated with coarse- grained aquifer materials adjacent to the screened intervals of the piezometers. Hydraulic-conductivity estimates ranged from 0.15 to 8.2 feet per day for aquifer materials adjacent to the screened intervals at 12 piezometers and from 12 to 41 feet per day for aquifer materials adjacent to the screened intervals at 10 piezometers. Hydraulic-conductivity estimates at four piezometers were greater than 41 feet per day.

  16. 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 PMID:27631614

  17. The dynamic process of atmospheric water sorption in [EMIM][Ac] and mixtures of [EMIM][Ac] with biopolymers and CO2 capture in these systems.

    PubMed

    Chen, Yu; Sun, Xiaofu; Yan, Chuanyu; Cao, Yuanyuan; Mu, Tiancheng

    2014-10-01

    There are mainly three findings related to the dynamic process of atmospheric water sorption in the ionic liquid (IL) 1-ethyl-3-methlyl-imidazolium acetate ([EMIM][Ac]) and its mixtures with biopolymers (i.e., cellulose, chitin, and chitosan), and CO2 capture in these systems above. The analytical methods mainly include gravimetric hygroscopicity measurement and in situ infrared spectroscopy with the techniques of difference, derivative, deconvoluted attenuated total reflectance and two-dimensional correlation. These three findings are listed as below. (1) Pure [EMIM][Ac] only shows a two-regime pattern, while all the mixtures of [EMIM][Ac] with biopolymers (i.e., cellulose, chitin, and chitosan) present a three-regime tendency for the dynamic process of atmospheric water sorption. Specifically, the IL/chitosan mixture has a clear three-regime mode; the [EMIM][Ac]/chitin mixture has an unclear indiscernible regime 3; and the [EMIM][Ac]/cellulose mixture shows an indiscernible regime 2. (2) [EMIM][Ac] and its mixtures with biopolymers could physically absorb a trace amount of and chemically react with a much larger amount of CO2 from the air. The chemisorption capacity of CO2 in these pure and mixed systems is ordered as chitosan/[EMIM][Ac] mixture > chitin/[EMIM][Ac] mixture > cellulose/[EMIM][Ac] mixture > pure [EMIM][Ac] (ca. 0.09 mass ratio % g/g CO2/IL). (3) The CO2 solubility in [EMIM][Ac] decreases about 50% after being exposed to the atmospheric moist air for some specific time period.

  18. The dynamic process of atmospheric water sorption in [EMIM][Ac] and mixtures of [EMIM][Ac] with biopolymers and CO2 capture in these systems.

    PubMed

    Chen, Yu; Sun, Xiaofu; Yan, Chuanyu; Cao, Yuanyuan; Mu, Tiancheng

    2014-10-01

    There are mainly three findings related to the dynamic process of atmospheric water sorption in the ionic liquid (IL) 1-ethyl-3-methlyl-imidazolium acetate ([EMIM][Ac]) and its mixtures with biopolymers (i.e., cellulose, chitin, and chitosan), and CO2 capture in these systems above. The analytical methods mainly include gravimetric hygroscopicity measurement and in situ infrared spectroscopy with the techniques of difference, derivative, deconvoluted attenuated total reflectance and two-dimensional correlation. These three findings are listed as below. (1) Pure [EMIM][Ac] only shows a two-regime pattern, while all the mixtures of [EMIM][Ac] with biopolymers (i.e., cellulose, chitin, and chitosan) present a three-regime tendency for the dynamic process of atmospheric water sorption. Specifically, the IL/chitosan mixture has a clear three-regime mode; the [EMIM][Ac]/chitin mixture has an unclear indiscernible regime 3; and the [EMIM][Ac]/cellulose mixture shows an indiscernible regime 2. (2) [EMIM][Ac] and its mixtures with biopolymers could physically absorb a trace amount of and chemically react with a much larger amount of CO2 from the air. The chemisorption capacity of CO2 in these pure and mixed systems is ordered as chitosan/[EMIM][Ac] mixture > chitin/[EMIM][Ac] mixture > cellulose/[EMIM][Ac] mixture > pure [EMIM][Ac] (ca. 0.09 mass ratio % g/g CO2/IL). (3) The CO2 solubility in [EMIM][Ac] decreases about 50% after being exposed to the atmospheric moist air for some specific time period. PMID:25208304

  19. 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.

  20. 47 CFR 15.207 - Conducted limits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... that is designed to be connected to the public utility (AC) power line, the radio frequency voltage... to be received using a standard AM broadcast receiver: no limit on conducted emissions. (2) For...

  1. 47 CFR 15.207 - Conducted limits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... that is designed to be connected to the public utility (AC) power line, the radio frequency voltage... to be received using a standard AM broadcast receiver: no limit on conducted emissions. (2) For...

  2. Operation Method for AC Motor Control during Power Interruption in Direct AC/AC Converter System

    NASA Astrophysics Data System (ADS)

    Shizu, Keiichiro; Azuma, Satoshi

    Direct AC/AC converters have been studied due to their potential use in power converters with no DC-link capacitor, which can contribute to the miniaturization of power converters. However, the absence of a DC-link capacitor makes it difficult to control the AC motor during power interruption. First, this paper proposes a system that realizes AC motor control during power interruption by utilizing a clamp capacitor. In general, direct AC/AC converters have a clamp circuit consisting of a rectifier diode(s) and a clamp capacitor in order to avoid over-voltages. In the proposed system, there is an additional semiconductor switch reverse-parallel to the rectifier diode(s), and the clamp capacitor voltage can be utilized for AC motor control by turning on the additional switch. Second, this paper discusses an operation method for AC motor control and clamp capacitor voltage control during power interruption. In the proposed method “DC-link voltage control”, the kinetic energy in the AC motor is transformed into electrical energy and stored in the clamp capacitor; the clamp capacitor is therefore charged and the capacitor voltage is controlled to remain constant at an instruction value. Third, this paper discusses a switching operation during power interruption. A dead-time is introduced between the operation of turning off all switches on the rectifier side and the operation of turning on the additional switch, which prevents the occurrence of a short circuit between the interrupted power source and the clamp capacitor. Finally, experimental results are presented. During power interruptions, an output current was continuously obtained and the clamp capacitor voltage was maintained to be equal to the instruction value of the capacitor voltage. These results indicate that both AC motor control and capacitor voltage control were successfully achieved by using the proposed system.

  3. ACS CCD Stability Monitor

    NASA Astrophysics Data System (ADS)

    Grogin, Norman

    2012-10-01

    A moderately crowded stellar field in the cluster 47 Tuc {6 arcmin West of the cluster core} is observed every four months with the WFC. The first visit exercises the full suite of broad and narrow band imaging filters and sub-array modes; following visits observe with only the six most popular Cycle 18 filters in full-frame mode. The positions and magnitudes of objects will be used to monitor local and large scale variations in the plate scale and the sensitivity of the detectors and to derive an independent measure of the detector CTE. One exposure in each sub-array mode with the WFC will allow us to verify that photometry obtained in full-frame and in sub-array modes are repeatable to better than 1%. This test is important for the ACS Photometric Cross-Calibration program, which uses sub-array exposures. This program may receive additional orbits to investigate ORIENT-dependent geometric distortion, which motivates the ORIENT and BETWEEN requirement on the first visit.

  4. The advantages and disadvantages of centralized control of air power at operational level

    NASA Astrophysics Data System (ADS)

    Arisoy, Uǧur

    2014-05-01

    People do not want to see and hear a war. In today's world, if war is inevitable, the use of air power is seen as the preferable means of conducting operations instead of financially burdensome land battles which are more likely to cause heavy loss of life. The use of Air Power has gained importance in NATO operations in the Post-Cold War era. For example, air power has undertaken a decisive role from the beginning to the end of the operation in Libya. From this point of view, the most important issue to consider is how to direct air power more effectively at operational level. NATO's Core JFAC (Joint Force Air Command) was established in 2012 to control joint air power at operational level from a single center. US had experienced JFAC aproach in the Operation Desert Storm in 1991. UK, France, Germany, Italy and Spain are also directing their air power from their JFAC structures. Joint air power can be directed from a single center at operational level by means of JFAC. JFAC aproach provides complex planning progress of Air Power to be controled faster in a single center. An Air Power with a large number of aircrafts, long range missiles of cutting-edge technology may have difficulties in achieving results unless directed effectively. In this article, directing air power more effectively at operational level has been studied in the framework of directing air power from a single center carried out by SWOT analysis technique. "Directing Air Power at operational level from a single center similar to JFAC-like structure" is compared with "Directing Air Power at operational level from two centers similar to AC (Air Command) + CAOC (Combined Air Operations Center) structure" As a result of this study, it is assessed that directing air power at operational level from a single center would bring effectiveness to the air campaign. The study examines directing air power at operational level. Developments at political, strategic and tactical levels have been ignored.

  5. Evaluation Framework and Analyses for Thermal Energy Storage Integrated with Packaged Air Conditioning

    SciTech Connect

    Kung, F.; Deru, M.; Bonnema, E.

    2013-10-01

    Few third-party guidance documents or tools are available for evaluating thermal energy storage (TES) integrated with packaged air conditioning (AC), as this type of TES is relatively new compared to TES integrated with chillers or hot water systems. To address this gap, researchers at the National Renewable Energy Laboratory conducted a project to improve the ability of potential technology adopters to evaluate TES technologies. Major project outcomes included: development of an evaluation framework to describe key metrics, methodologies, and issues to consider when assessing the performance of TES systems integrated with packaged AC; application of multiple concepts from the evaluation framework to analyze performance data from four demonstration sites; and production of a new simulation capability that enables modeling of TES integrated with packaged AC in EnergyPlus. This report includes the evaluation framework and analysis results from the project.

  6. Superconducting shielded core reactor with reduced AC losses

    DOEpatents

    Cha, Yung S.; Hull, John R.

    2006-04-04

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

  7. 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.

  8. Indoor air quality in Brazilian universities.

    PubMed

    Jurado, Sonia R; Bankoff, Antônia D P; Sanchez, Andrea

    2014-07-11

    This study evaluated the indoor air quality in Brazilian universities by comparing thirty air-conditioned (AC) (n = 15) and naturally ventilated (NV) (n = 15) classrooms. The parameters of interest were indoor carbon dioxide (CO2), temperature, relative humidity (RH), wind speed, viable mold, and airborne dust levels. The NV rooms had larger concentration of mold than the AC rooms (1001.30 ± 125.16 and 367.00 ± 88.13 cfu/m3, respectively). The average indoor airborne dust concentration exceeded the Brazilian standards (<80 µg/m3) in both NV and AC classrooms. The levels of CO2 in the AC rooms were significantly different from the NV rooms (1433.62 ± 252.80 and 520.12 ± 37.25 ppm, respectively). The indoor air quality in Brazilian university classrooms affects the health of students. Therefore, indoor air pollution needs to be considered as an important public health problem.

  9. Oxygen and carbon isotopic signatures reveal a long-term effect of free-air ozone enrichment on leaf conductance in semi-natural grassland

    NASA Astrophysics Data System (ADS)

    Jäggi, M.; Fuhrer, J.

    The effect of ozone on leaf gas diffusion was investigated by analyzing the stable oxygen isotopic signatures (δ 18O) in leaves of Holcus lanatus L., Plantago lanceolata L., Ranunculus friesianus (Jord.), and Trifolium pratense L. grown in temperate, semi-natural grassland. Dried material from plants exposed to ambient or elevated ozone levels in a long-term free-air experiment was sampled in 2002 and 2003. A general increase in δ 18O in elevated ozone indicated increased limitation to gas diffusion, which was strongest during the driest and warmest period in 2003. In three out of four species, the increase in δ 18O paralleled an increase in δ 13C measured earlier in the same samples, meaning that the dominant effect of ozone was on gas diffusion and not on CO 2 fixation. Only in R. friesianus, ozone affected both processes simultaneously. It is concluded that elevated ozone not only affects productivity, but also the water status of important component species of grassland communities.

  10. 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. PMID:23218240

  11. 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.

  12. Spray-on polyvinyl alcohol separators and impact on power production in air-cathode microbial fuel cells with different solution conductivities.

    PubMed

    Hoskins, Daniel L; Zhang, Xiaoyuan; Hickner, Michael A; Logan, Bruce E

    2014-11-01

    Separators are used to protect cathodes from biofouling and to avoid electrode short-circuiting, but they can adversely affect microbial fuel cell (MFC) performance. A spray method was used to apply a polyvinyl alcohol (PVA) separator to the cathode. Power densities were unaffected by the PVA separator (339±29mW/m(2)), compared to a control lacking a separator in a low conductivity solution (1mS/cm) similar to wastewater. Power was reduced with separators in solutions typical of laboratory tests (7-13mS/cm), compared to separatorless controls. The PVA separator produced more power in a separator assembly (SEA) configuration (444±8mW/m(2)) in the 1mS/cm solution, but power was reduced if a PVA or wipe separator was used in higher conductivity solutions with either Pt or activated carbon catalysts. Spray and cast PVA separators performed similarly, but the spray method is preferred as it was easier to apply and use.

  13. Alkaline composite PEO-PVA-glass-fibre-mat polymer electrolyte for Zn-air battery

    NASA Astrophysics Data System (ADS)

    Yang, Chun-Chen; Lin, Sheng-Jen

    An alkaline composite PEO-PVA-glass-fibre-mat polymer electrolyte with high ionic conductivity (10 -2 S cm -1) at room temperature has been prepared and applied to solid-state primary Zn-air batteries. The electrolyte shows excellent mechanical strength. The electrochemical characteristics of the batteries were experimentally investigated by means of ac impedance spectroscopy and galvanostatic discharge. The results indicate that the PEO-PVA-glass-fibre-mat composite polymer electrolyte is a promising candidate for application in alkaline primary Zn-air batteries.

  14. Three-phase ac-to-ac series-resonant power converter with a reduced number of thyristors

    SciTech Connect

    Klaassens, J.B.; de Beer, F. )

    1991-07-01

    This paper reports that ac-ac series-resonant converters have been proven to be functional and useful. Power pulse modulation with internal frequencies of tens of kHz and suited for multikilowatt power levels is applied to a series-resonant converter system for generating synthesized multiphase bipolar waveforms with reversible power flow and flow distortion. The use of a series-resonant circuit for power transfer and control obtains natural current commutation of the thyristors and the prevention of excessive stresses on components. Switches are required which have bidirectional current conduction and voltage blocking ability. The conventional series-resonant ac-ac converter applies a total for 24 anti-parallel thyristors. An alternative circuit configuration for the series-resonant ac-ac converter with only 12 thyristors is also presented. The alternative power circuit has three neutrals, related to the polyphase source, the load and the converter, which may be interconnected. If they are connected, the high-frequency component of the source and load currents will flow through the connection between the neutrals. The test results of a converter system generating three-phase sinusoidal input and output waveforms have demonstrated the significant aspects of this type of power interfaces.

  15. Cooling of Gas Turbines I - Effects of Addition of Fins to Blade Tips and Rotor, Admission of Cooling Air Through Part of Nozzles, and Change in Thermal Conductivity of Turbine Components

    NASA Technical Reports Server (NTRS)

    Brown, Byron

    1947-01-01

    An analysis was developed for calculating the radial temperature distribution in a gas turbine with only the temperatures of the gas and the cooling air and the surface heat-transfer coefficient known. This analysis was applied to determine the temperatures of a complete wheel of a conventional single-stage impulse exhaust-gas turbine. The temperatures were first calculated for the case of the turbine operating at design conditions of speed, gas flow, etc. and with only the customary cooling arising from exposure of the outer blade flange and one face of the rotor to the air. Calculations were next made for the case of fins applied to the outer blade flange and the rotor. Finally the effects of using part of the nozzles (from 0 to 40 percent) for supplying cooling air and the effects of varying the metal thermal conductivity from 12 to 260 Btu per hour per foot per degree Farenheit on the wheel temperatures were determined. The gas temperatures at the nozzle box used in the calculations ranged from 1600F to 2000F. The results showed that if more than a few hundred degrees of cooling of turbine blades are required other means than indirect cooling with fins on the rotor and outer blade flange would be necessary. The amount of cooling indicated for the type of finning used could produce some improvement in efficiency and a large increase in durability of the wheel. The results also showed that if a large difference is to exist between the effective temperature of the exhaust gas and that of the blade material, as must be the case with present turbine materials and the high exhaust-gas temperatures desired (2000F and above), two alternatives are suggested: (a) If metal with a thermal conductivity comparable with copper is used, then the blade temperature can be reduced by strong cooling at both the blade tip and root. The center of the blade will be less than 2000F hotter than the ends; (b) With low conductivity materials some method of direct cooling other than

  16. Preliminary Geologic Mapping of the Ac-S-3 Hemisphere of Ceres from NASA's Dawn Mission

    NASA Astrophysics Data System (ADS)

    Buczkowski, D. L.; Yingst, R. A.; Williams, D. A.; Scully, J. E. C.; Mest, S. C.; Crown, D. A.; Jaumann, R.; Russell, C. T.; Raymond, C. A.; Schenk, P. M.; Marchi, S.; O'Brien, D. P.; Nathues, A.; Hoffmann, M.; Schafer, M.; Platz, T.; Roatsch, T.; Kersten, E.; Preusker, F.; Stephan, K.

    2015-10-01

    NASA's Dawn spacecraft [1] was captured into orbit by the dwarf planet (1) Ceres on March 6, 2015. During the Approach phase capture was preceded and followed by a series of optical navigation and rotation characterization observations by Dawn's Framing Camera (FC) [2], which provided the first images of Ceres' surface. As was done at Vesta [3], the Dawn Science Team will conduct a geological mapping campaign at Ceres during the Nominal Mission, including iterative mapping using data obtained during each orbital phase. In this presentation we will describe the approach of the Ceres Mapping Campaign and discuss the preliminary geological mapping of the Ac-S-3 (180- 360˚E) hemisphere of Ceres.

  17. AC Electroosmotic Pumping in Nanofluidic Funnels.

    PubMed

    Kneller, Andrew R; Haywood, Daniel G; Jacobson, Stephen C

    2016-06-21

    We report efficient pumping of fluids through nanofluidic funnels when a symmetric AC waveform is applied. The asymmetric geometry of the nanofluidic funnel induces not only ion current rectification but also electroosmotic flow rectification. In the base-to-tip direction, the funnel exhibits a lower ion conductance and a higher electroosmotic flow velocity, whereas, in the tip-to-base direction, the funnel has a higher ion conductance and a lower electroosmotic flow velocity. Consequently, symmetric AC waveforms easily pump fluid through the nanofunnels over a range of frequencies, e.g., 5 Hz to 5 kHz. In our experiments, the nanofunnels were milled into glass substrates with a focused ion beam (FIB) instrument, and the funnel design had a constant 5° taper with aspect ratios (funnel tip width to funnel depth) of 0.1 to 1.0. We tracked ion current rectification by current-voltage (I-V) response and electroosmotic flow rectification by transport of a zwitterionic fluorescent probe. Rectification of ion current and electroosmotic flow increased with increasing electric field applied to the nanofunnel. Our results support three-dimensional simulations of ion transport and electroosmotic transport through nanofunnels, which suggest the asymmetric electroosmotic transport stems from an induced pressure at the junction of the nanochannel and nanofunnel tip. PMID:27230495

  18. Cartilage conduction is characterized by vibrations of the cartilaginous portion of the ear canal.

    PubMed

    Nishimura, Tadashi; Hosoi, Hiroshi; Saito, Osamu; Miyamae, Ryosuke; Shimokura, Ryota; Yamanaka, Toshiaki; Kitahara, Tadashi; Levitt, Harry

    2015-01-01

    Cartilage conduction (CC) is a new form of sound transmission which is induced by a transducer being placed on the aural cartilage. Although the conventional forms of sound transmission to the cochlea are classified into air or bone conduction (AC or BC), previous study demonstrates that CC is not classified into AC or BC (Laryngoscope 124: 1214-1219). Next interesting issue is whether CC is a hybrid of AC and BC. Seven volunteers with normal hearing participated in this experiment. The threshold-shifts by water injection in the ear canal were measured. AC, BC, and CC thresholds at 0.5-4 kHz were measured in the 0%-, 40%-, and 80%-water injection conditions. In addition, CC thresholds were also measured for the 20%-, 60%-, 100%-, and overflowing-water injection conditions. The contributions of the vibrations of the cartilaginous portion were evaluated by the threshold-shifts. For AC and BC, the threshold-shifts by the water injection were 22.6-53.3 dB and within 14.9 dB at the frequency of 0.5-4 kHz, respectively. For CC, when the water was filled within the bony portion, the thresholds were elevated to the same degree as AC. When the water was additionally injected to reach the cartilaginous portion, the thresholds at 0.5 and 1 kHz dramatically decreased by 27.4 and 27.5 dB, respectively. In addition, despite blocking AC by the injected water, the CC thresholds in force level were remarkably lower than those for BC. The vibration of the cartilaginous portion contributes to the sound transmission, particularly in the low frequency range. Although the airborne sound is radiated into the ear canal in both BC and CC, the mechanism underlying its generation is different between them. CC generates airborne sound in the canal more efficiently than BC. The current findings suggest that CC is not a hybrid of AC and BC.

  19. Detecting adaptive evolution and functional divergence in aminocyclopropane-1-carboxylate synthase (ACS) gene family.

    PubMed

    Zhang, Ti-Cao; Qiao, Qin; Zhong, Yang

    2012-06-01

    Ethylene is an essential plant gaseous hormone that controls many aspects of plant growth and development, especially the fruit ripening. It is important to know how this hormone is synthesized and how its production is regulated to understand the roles of ethylene in plant development. The aminocyclopropane-1-carboxylate synthase (ACS) gene is a rate-limiting enzyme in the ethylene biosynthesis pathway, which is encoded by a highly divergent multi-gene family in plant species. Although many ACS genes have been cloned from a wide variety of plant species previously, their origin and evolutionary process are still not clear. In this study, we conducted a phylogenetic analysis based on an updated dataset including 107 members of plant ACS genes and eight ACS-like genes from animal as well as six AATase genes. The motifs were identified and the positive selection and functional divergence in the ACS gene family were detected. The results obtained from these analyses are consistent with previous division of the ACS gene family in angiosperm, i.e., three distinct clades, and show that the duplications of three subclades (I, II and III) ACS genes have occurred after the divergence of gymnosperm and angiosperm. We conclude that the ACS genes could have experienced three times significant positive selection as they underwent expansion in land plants and gain the full-scale ethylene biosynthesis and regulatory functions, and all plant ACS genes originated from plant-ACS-like genes which come from AATase genes.

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

    PubMed Central

    Chang, Ing-Feng

    2013-01-01

    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. PMID:23943848

  1. Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz tone pips.

    PubMed

    Todd, N P M; Paillard, A C; Kluk, K; Whittle, E; Colebatch, J G

    2014-06-01

    Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulation and by conducting a source analysis of the resulting evoked potentials of short and long latency. Ten healthy, right-handed subjects were recruited and evoked potentials were recorded to both left- and right-ear sound stimulation, above and below vestibular threshold. Below VEMP threshold, typical AEPs were recorded, consisting of mid-latency (MLR) waves Na and Pa followed by long latency AEPs (LAEPs) N1 and P2. In the supra-threshold condition, the expected changes in morphology were observed, consisting of: (1) short-latency vestibular evoked potentials (VsEPs) which have no auditory correlate, i.e. the ocular VEMP (OVEMP) and inion response related potentials; (2) a later deflection, labelled N42/P52, followed by the LAEPs N1 and P2. Statistical analysis of the vestibular dependent responses indicated a contralateral effect for inion related short-latency responses and a left-ear/right-hemisphere advantage for the long-latency responses. Source analysis indicated that the short-latency effects may be mediated by a contralateral projection to left cerebellum, while the long-latency effects were mediated by a contralateral projection to right cingulate cortex. In addition we found evidence of a possible vestibular contribution to the auditory T-complex in radial temporal lobe sources. These last results raise the possibility that acoustic activation of the otolith organs could potentially contribute to auditory processing.

  2. Interactive effects of soil water deficit and air vapour pressure deficit on mesophyll conductance to CO2 in Vitis vinifera and Olea europaea.

    PubMed

    Perez-Martin, A; Flexas, J; Ribas-Carbó, M; Bota, J; Tomás, M; Infante, J M; Diaz-Espejo, A

    2009-01-01

    The present work aims to study the interactive effect of drought stress and high vapour pressure deficit (VPD) on leaf gas exchange, and especially on mesophyll conductance to CO(2) (g(m)), in two woody species of great agronomical importance in the Mediterranean basin: Vitis vinifera L. cv. Tempranillo and Olea europaea L. cv. Manzanilla. Plants were grown in specially designed outdoor chambers with ambient and below ambient VPD, under both well-irrigated and drought conditions. g(m) was estimated by the variable J method from simultaneous measurements of gas exchange and fluorescence. In both species, the response to soil water deficit was larger in g(s) than in g(m), and more important than the response to VPD. Olea europaea was apparently more sensitive to VPD, so that plants growing in more humid chambers showed higher g(s) and g(m). In V. vinifera, in contrast, soil water deficit dominated the response of g(s) and g(m). Consequently, changes in g(m)/g(s) were more related to VPD in O. europaea and to soil water deficit in V. vinifera. Most of the limitations of photosynthesis were diffusional and especially due to stomatal closure. No biochemical limitation was detected. The results showed that structural parameters played an important role in determining g(m) during the acclimation process. Although the relationship between leaf mass per unit area (M(A)) with g(m) was scattered, it imposed a limitation to the maximum g(m) achievable, with higher values of M(A) in O. europaea at lower g(m) values. M(A) decreased under water stress in O. europaea but it increased in V. vinifera. This resulted in a negative relationship between M(A) and the CO(2) draw-down between substomatal cavities and chloroplasts in O. europaea, while being positive in V. vinifera. PMID:19457982

  3. 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.

  4. The ac53, ac78, ac101, and ac103 Genes Are Newly Discovered Core Genes in the Family Baculoviridae

    PubMed Central

    Garavaglia, Matías Javier; Miele, Solange Ana Belén; Iserte, Javier Alonso; Belaich, Mariano Nicolás

    2012-01-01

    The family Baculoviridae is a large group of insect viruses containing circular double-stranded DNA genomes of 80 to 180 kbp, which have broad biotechnological applications. A key feature to understand and manipulate them is the recognition of orthology. However, the differences in gene contents and evolutionary distances among the known members of this family make it difficult to assign sequence orthology. In this study, the genome sequences of 58 baculoviruses were analyzed, with the aim to detect previously undescribed core genes because of their remote homology. A routine based on Multi PSI-Blast/tBlastN and Multi HaMStR allowed us to detect 31 of 33 accepted core genes and 4 orthologous sequences in the Baculoviridae which were not described previously. Our results show that the ac53, ac78, ac101 (p40), and ac103 (p48) genes have orthologs in all genomes and should be considered core genes. Accordingly, there are 37 orthologous genes in the family Baculoviridae. PMID:22933288

  5. Semiconductor ac static power switch

    NASA Technical Reports Server (NTRS)

    Vrancik, J.

    1968-01-01

    Semiconductor ac static power switch has long life and high reliability, contains no moving parts, and operates satisfactorily in severe environments, including high vibration and shock conditions. Due to their resistance to shock and vibration, static switches are used where accidental switching caused by mechanical vibration or shock cannot be tolerated.

  6. Interaction of temperature, humidity, driver preferences, and refrigerant type on air conditioning compressor usage.

    PubMed

    Levine, C; Younglove, T; Barth, M

    2000-10-01

    Recent studies have shown large increases in vehicle emissions when the air conditioner (AC) compressor is engaged. Factors that affect the compressor-on percentage can have a significant impact on vehicle emissions and can also lead to prediction errors in current emissions models if not accounted for properly. During 1996 and 1997, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) conducted a vehicle activity study for the California Air Resources Board (CARB) in the Sacramento, CA, region. The vehicles were randomly selected from all registered vehicles in the region. As part of this study, ten vehicles were instrumented to collect AC compressor on/off data on a second-by-second basis in the summer of 1997. Temperature and humidity data were obtained and averaged on an hourly basis. The ten drivers were asked to complete a short survey about AC operational preferences. This paper examines the effects of temperature, humidity, refrigerant type, and driver preferences on air conditioning compressor activity. Overall, AC was in use in 69.1% of the trips monitored. The compressor was on an average of 64% of the time during the trips. The personal preference settings had a significant effect on the AC compressor-on percentage but did not interact with temperature. The refrigerant types, however, exhibited a differential response across temperature, which may necessitate separate modeling of the R12 refrigerant-equipped vehicles from the R134A-equipped vehicles. It should be noted that some older vehicles do get retrofitted with new compressors that use R134A; however, none of the vehicles in this study had been retrofitted.

  7. 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)

  8. AC Loss Measurements on a 2G YBCO Coil

    SciTech Connect

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

    2011-01-01

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

  9. 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.

  10. 47 CFR 15.107 - Conducted limits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Conducted limits. (a) Except for Class A digital devices, for equipment that is designed to be connected to... device that is designed to be connected to the public utility (AC) power line, the radio frequency... intended to be received using a standard AM broadcast receiver: no limit on conducted emissions. (2)...

  11. ACS Expands Role In High School Chemistry.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1979

    1979-01-01

    Describes some of the services and programs of special interests to high school chemistry teachers that are being provided by ACS, and meant to make ACS membership more attractive to the teachers. (GA)

  12. 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.

  13. Distribution of Activator (Ac) Throughout the Maize Genome for Use in Regional Mutagenesis

    PubMed Central

    Kolkman, Judith M.; Conrad, Liza J.; Farmer, Phyllis R.; Hardeman, Kristine; Ahern, Kevin R.; Lewis, Paul E.; Sawers, Ruairidh J. H.; Lebejko, Sara; Chomet, Paul; Brutnell, Thomas P.

    2005-01-01

    A collection of Activator (Ac)-containing, near-isogenic W22 inbred lines has been generated for use in regional mutagenesis experiments. Each line is homozygous for a single, precisely positioned Ac element and the Ds reporter, r1-sc:m3. Through classical and molecular genetic techniques, 158 transposed Ac elements (tr-Acs) were distributed throughout the maize genome and 41 were precisely placed on the linkage map utilizing multiple recombinant inbred populations. Several PCR techniques were utilized to amplify DNA fragments flanking tr-Ac insertions up to 8 kb in length. Sequencing and database searches of flanking DNA revealed that the majority of insertions are in hypomethylated, low- or single-copy sequences, indicating an insertion site preference for genic sequences in the genome. However, a number of Ac transposition events were to highly repetitive sequences in the genome. We present evidence that suggests Ac expression is regulated by genomic context resulting in subtle variations in Ac-mediated excision patterns. These tr-Ac lines can be utilized to isolate genes with unknown function, to conduct fine-scale genetic mapping experiments, and to generate novel allelic diversity in applied breeding programs. PMID:15520264

  14. Project Completion Report on China's Room AC Reach Standard

    SciTech Connect

    Lin, Jiang

    2005-03-10

    After much anticipation and hard work, China's reach standard for room air-conditioners was announced in September 2004, with the first tier going into effect on March 1, 2005 and the reach standard taking effect on January 1, 2009. This is a major milestone in the development of minimum energy efficiency standards in China: finally China has set a minimum standard that is meaningful and stringent. According to our preliminary analysis, the majority of room ACs products on the Chinese market in 2004 would not meet the 2009 reach standard requirement. In addition to setting the minimum requirement, China's new AC standard also include classification requirement for the newly established Energy Information Label, as well as the certification requirement for CECP's Energy Conservation Label. Highlights of the 2009 reach standard include: (1) The Chinese Reach Standard for Room AC in 2009 is tighter than American counterpart, and almost matches the efficiency of American Central Air-Conditioners; and (2) Summer peak demand reduction in 2020 due to the reach standard exceeds the capacity of the Three Gorges Project.

  15. 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.

  16. In-Cab Air Quality of Trucks Air Conditioned and Kept in Electrified Truck Stop

    SciTech Connect

    Lee, Doh-Won; Zietsman, Josias; Farzaneh, Mohamadreza; Li, Wen-Whai; Olvera, Hector; Storey, John Morse; Kranendonk, Laura

    2009-01-01

    At night, long-haul truck drivers rest inside the cabins of their vehicles. Therefore, the in-cab air quality while air conditioning (A/C) is being provided can be a great concern to the drivers health. The effect of using different A/C methods [truck's A/C, auxiliary power unit (APU), and truck stop electrification (TSE) unit] on in-cab air quality of a heavy-duty diesel vehicle was investigated at an electrified truck stop in the El Paso, Texas, area. The research team measured the in-cabin and the ambient air quality adjacent to the parked diesel truck as well as emissions from the truck and an APU while it was providing A/C. The measured results were compared and analyzed. On the basis of these results, it was concluded that the TSE unit provided better in-cab air quality while supplying A/C. Furthermore, the truck and APU exhaust emissions were measured, and fuel consumption of the truck (while idling) and the APU (during operation) were compared. The results led to the finding that emissions from the APU were less than those from the truck's engine idling, but the APU consumed more fuel than the engine while providing A/C under given conditions.

  17. Development and Analysis of Desiccant Enhanced Evaporative Air Conditioner Prototype

    SciTech Connect

    Kozubal, E.; Woods, J.; Judkoff, R.

    2012-04-01

    This report documents the design of a desiccant enhanced evaporative air conditioner (DEVAP AC) prototype and the testing to prove its performance. Previous numerical modeling and building energy simulations indicate a DEVAP AC can save significant energy compared to a conventional vapor compression AC (Kozubal et al. 2011). The purposes of this research were to build DEVAP prototypes, test them to validate the numerical model, and identify potential commercialization barriers.

  18. Acidic and alkaline pretreatments of activated carbon and their effects on the performance of air-cathodes in microbial fuel cells.

    PubMed

    Wang, Xin; Gao, Ningshengjie; Zhou, Qixing; Dong, Heng; Yu, Hongbing; Feng, Yujie

    2013-09-01

    Activated carbon (AC) is a high performing and cost effective catalyst for oxygen reduction reactions (ORRs) of air-cathodes in microbial fuel cells (MFCs). Acidic (HNO3) and alkaline (KOH) pretreatments on AC at low temperature (85°C) are conducted to enhance the performance of MFCs. The alkaline pretreatment increased the power density by 16% from 804±70 to 957±31 mW m(-2), possibly due to the decrease of ohmic resistance (from 20.58 to 19.20 Ω) and the increase of ORR activities provided by the adsorbed hydroxide ion and extra micropore area/volume after alkaline pretreatment. However, acidic pretreatment decreased the power output to 537±36 mW m(-2), which can be mainly attributed to the corrosion by adsorbed proton at the interface of AC powder and stainless steel mesh and the decreased pore area.

  19. Acidic and alkaline pretreatments of activated carbon and their effects on the performance of air-cathodes in microbial fuel cells.

    PubMed

    Wang, Xin; Gao, Ningshengjie; Zhou, Qixing; Dong, Heng; Yu, Hongbing; Feng, Yujie

    2013-09-01

    Activated carbon (AC) is a high performing and cost effective catalyst for oxygen reduction reactions (ORRs) of air-cathodes in microbial fuel cells (MFCs). Acidic (HNO3) and alkaline (KOH) pretreatments on AC at low temperature (85°C) are conducted to enhance the performance of MFCs. The alkaline pretreatment increased the power density by 16% from 804±70 to 957±31 mW m(-2), possibly due to the decrease of ohmic resistance (from 20.58 to 19.20 Ω) and the increase of ORR activities provided by the adsorbed hydroxide ion and extra micropore area/volume after alkaline pretreatment. However, acidic pretreatment decreased the power output to 537±36 mW m(-2), which can be mainly attributed to the corrosion by adsorbed proton at the interface of AC powder and stainless steel mesh and the decreased pore area. PMID:23890977

  20. 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)

  1. Small-Signal ac Analysis

    NASA Technical Reports Server (NTRS)

    Jagielski, James M.; Chen, Jess

    1987-01-01

    Program simulates power circuits and systems. Small Signal A.C. Analysis program (SSAC) valuable tool for design and analysis of electrical-power-system circuits. By combining "black box" power-system components operating in specified manner, user characterizes system modeled. Menu-driven program proved simple and cost effective in development and modification of arbitrary power-system configurations. Package includes sample data from Dynamic Explorer satellite family. Results compared favorable to calculations from such general circuit-analysis programs as SPICE. Written in FORTRAN 77.

  2. PHASE I PILOT AIR CONVEYANCE SYSTEM DESIGN, CLEANING, AND CHARACTERIZATION

    EPA Science Inventory

    The report gives results of a project to develop and refine surface and airborne contamination
    measurement techniques that can be used to evaluate air conveyance system (ACS) cleaning.
    (NOTE: ACS cleaning is advertized to homeowners as a service having a number of benefits...

  3. High frequency bone conduction auditory evoked potentials in the guinea pig: Assessing cochlear injury after ossicular chain manipulation.

    PubMed

    Bergin, M J; Bird, P A; Vlajkovic, S M; Thorne, P R

    2015-12-01

    Permanent high frequency (>4 kHz) sensorineural hearing loss following middle ear surgery occurs in up to 25% of patients. The aetiology of this loss is poorly understood and may involve transmission of supra-physiological forces down the ossicular chain to the cochlea. Investigating the mechanisms of this injury using animal models is challenging, as evaluating cochlear function with evoked potentials is confounded when ossicular manipulation disrupts the normal air conduction (AC) pathway. Bone conduction (BC) using clinical bone vibrators in small animals is limited by poor transducer output at high frequencies sensitive to trauma. The objectives of the present study were firstly to evaluate a novel high frequency bone conduction transducer with evoked auditory potentials in a guinea pig model, and secondly to use this model to investigate the impact of middle ear surgical manipulation on cochlear function. We modified a magnetostrictive device as a high frequency BC transducer and evaluated its performance by comparison with a calibrated AC transducer at frequencies up to 32 kHz using the auditory brainstem response (ABR), compound action potential (CAP) and summating potential (SP). To mimic a middle ear traumatising stimulus, a rotating bur was brought in to contact with the incudomalleal complex and the effect on evoked cochlear potentials was observed. BC-evoked potentials followed the same input-output function pattern as AC potentials for all ABR frequencies. Deterioration in CAP and SP thresholds was observed after ossicular manipulation. It is possible to use high frequency BC to evoke responses from the injury sensitive basal region of the cochlea and so not rely on AC with the potential confounder of conductive hearing loss. Ongoing research explores how these findings evolve over time, and ways in which injury may be reduced and the cochlea protected during middle ear surgery.

  4. Nonlinear alternating current conduction in polycrystalline manganites

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    The real part of ac conductance Σ(T, f) of yttrium-doped mixed-valent polycrystalline manganite systems La1-x -yYyCaxMnO3 with x = 0.33 and 0.05 and y = 0.07 and iron doped LaMn1-xFexO3 with x = 0.15 is measured as a function of frequency f by varying zero-frequency Ohmic conductance Σ0 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 Σ0 up to a certain frequency, known as the onset frequency fc and increases from Σ0 as frequency is increased from fc. 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. fc scales with Σ0 as fc˜Σ0xf, where xf is the nonlinearity exponent characterising the onset. With the help of data for ac conduction, it is shown that xf 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 xf.

  5. 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.

  6. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  7. In-car particles and cardiovascular health: an air conditioning-based intervention study.

    PubMed

    Chuang, Hsiao-Chi; Lin, Lian-Yu; Hsu, Ya-Wen; Ma, Chih-Ming; Chuang, Kai-Jen

    2013-05-01

    Exposure to traffic-related particulate matter (PM) is considered a potential risk for cardiovascular events. Little is known about whether improving air quality in car can modify cardiovascular effects among human subjects during commuting. We recruited a panel of 60 healthy subjects to commute for 2 h by a car equipped with an air conditioning (AC) system during the morning rush hour in Taipei. Operation modes of AC system using outside air (OA-mode), circulating inside air (IA-mode) and turning off (Off-mode) were examined. Repeated measurements of heart rate variability (HRV) indices, PM≤2.5 μm in aerodynamic diameter (PM2.5) and noise level were conducted for each participant in different modes during the commute. We used linear mixed-effects models to associate HRV indices with in-car PM2.5. We found that decreases in HRV indices were associated with increased levels of in-car PM2.5. For Off-mode, an interquartile range (IQR) increase in in-car PM2.5 with 15-min moving average was associated with 2.7% and 4.1% decreases in standard deviation of NN intervals (SDNN) and the square root of the mean of the sum of the squares of differences between adjacent NN intervals (r-MSSD), respectively. During OA and IA modes, participants showed slight decreases in SDNN (OA mode: 0.1%; IA mode: 1.3%) and r-MSSD (OA mode: 1.1%; IA mode: 1.8%) by an IQR increase in in-car PM2.5 with 15-min moving average. We concluded that in-car PM2.5 is associated with autonomic alteration. Utilization of the car's AC system can improve air quality and modify the effects of in-car PM2.5 on HRV indices among human subjects during the commute.

  8. 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.

  9. 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.

  10. 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

    2016-01-01

    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.

  11. 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…

  12. 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.

  13. 47 CFR 15.315 - Conducted limits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unlicensed Personal 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....

  14. Electrodeless conductivity.

    PubMed

    Light, T S; McHale, E J; Fletcher, K S

    1989-01-01

    Electrodeless conductivity is a technique for measuring the concentration of electrolytes in solution and utilizes a probe consisting of two toroids in close proximity, both of which are immersed in the solution. In special cases, the toroids may be mounted externally on insulated pipes carrying the solution. One toroid radiates an alternating electric field in the audiofrequency range and the other acts as a receiver to pick up the small current induced by the ions moving in a conducting loop of solution. Coatings which would foul contacting electrodes, such as suspensions, precipitates or oil, have little or no effect. Applications are chiefly to continuous measurement in the chemical processing industries, including pulp and paper, mining and heavy chemical production. The principles and practical details of the method are reviewed and cell-diameter, wall, and temperature effects are discussed. PMID:18964695

  15. Conductive Polymers

    SciTech Connect

    Bohnert, G.W.

    2002-11-22

    Electroluminescent devices such as light-emitting diodes (LED) and high-energy density batteries. These new polymers offer cost savings, weight reduction, ease of processing, and inherent rugged design compared to conventional semiconductor materials. The photovoltaic industry has grown more than 30% during the past three years. Lightweight, flexible solar modules are being used by the U.S. Army and Marine Corps for field power units. LEDs historically used for indicator lights are now being investigated for general lighting to replace fluorescent and incandescent lights. These so-called solid-state lights are becoming more prevalent across the country since they produce efficient lighting with little heat generation. Conductive polymers are being sought for battery development as well. Considerable weight savings over conventional cathode materials used in secondary storage batteries make portable devices easier to carry and electric cars more efficient and nimble. Secondary battery sales represent an $8 billion industry annually. The purpose of the project was to synthesize and characterize conductive polymers. TRACE Photonics Inc. has researched critical issues which affect conductivity. Much of their work has focused on production of substituted poly(phenylenevinylene) compounds. These compounds exhibit greater solubility over the parent polyphenylenevinylene, making them easier to process. Alkoxy substituted groups evaluated during this study included: methoxy, propoxy, and heptyloxy. Synthesis routes for production of alkoxy-substituted poly phenylenevinylene were developed. Considerable emphasis was placed on final product yield and purity.

  16. Improvement program for polycarbonate capacitors. [hermetically sealed, and ac wound

    NASA Technical Reports Server (NTRS)

    Bailey, R. R.; Waterman, K. D.

    1973-01-01

    Hermetically sealed, wound, AC, polycarbonate capacitors incorporating design improvements recommended in a previous study were designed and built. A 5000 hour, 400 Hz ac life test was conducted using 384 of these capacitors to verify the adequacy of the design improvements. The improvements incorporated in the capacitors designed for this program eliminated the major cause of failure found in the preceding work, termination failure. A failure cause not present in the previous test became significant in this test with capacitors built from one lot of polycarbonate film. The samples from this lot accounted for 25 percent of the total test complement. Analyses of failed samples showed that the film had an excessive solvent content. This solvent problem was found in 37 of the total 46 failures which occurred in this test. The other nine were random failures resulting from causes such as seal leaks, foreign particles, and possibly wrinkles.

  17. [Effect of prostatilen AC suppositories on course of experimental prostatitis].

    PubMed

    Savateeva-Liubimova, T N; Sivak, K V; Malinin, V V

    2012-01-01

    The article presents the results of evaluation of efficacy of new drug prostatilen AC (rectal suppositories), containing regulatory peptides of the bovine prostate and zinc arginate-glycinate complex, in the treatment of prostatitis. The experiment was conducted on 40 Sprague-Dawley rats weighing 180-200 g. Chronic prostatitis was modeled by injection of 10% Dimexidum in combination with water, mixed with turpentine, a volumetric ratio of 4:1. It is shown that prostatilen AC has pronounced organotropic antiinflammatory effect, which manifests in reducing the weight of the prostate, reducing the protein level in the urine, activity of acid phosphatase, and levels of ceruloplasmin and C-reactive protein. In addition, this drug normalizes the act of urination and increases the diurnal diuresis, has antioxidant properties and increases the blood level of the male sex hormone testosterone.

  18. 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.

  19. Air Controlman 3 and 2: Naval Rate Training Manual and Nonresident Career Course.

    ERIC Educational Resources Information Center

    Naval Education and Training Command, Pensacola, FL.

    The Rate Training Manual is one of a series of training manuals prepared for enlisted personnel of the Navy and Naval Reserve studying for advancement in the Air Controlman (AC) rating to Air Controlman Third and Second Class. Chapter 1 discusses air controlman qualifications, the enlisted rating structure, the Air Controlman rating, references…

  20. Properties of air and combustion products of fuel with air

    NASA Technical Reports Server (NTRS)

    Poferl, D. J.; Svehla, R. A.

    1975-01-01

    Thermodynamic and transport properties have been calculated for air, the combustion products of natural gas and air, and combustion products of ASTM-A-1 jet fuel and air. Properties calculated include: ratio of specific heats, molecular weight, viscosity, specific heat, thermal conductivity, Prandtl number, and enthalpy.

  1. Electrically conductive ceramic powders

    NASA Astrophysics Data System (ADS)

    Lu, Yanxia

    1999-11-01

    moisture was studied. Three classifications of structure were identified for alkali-doped titanium oxides: (1) Pure titanium dioxide phase with alkali ions located in interstitial positions. (2) The titanium bronze phases. (3) Alkali-doped titanium oxides. Highly conductive powders were obtained in the first and second classifications with conductivity of 10-2 to 10° S/cm. Materials in the third classification had poor conductivity below 10-3 S/cm. The conductivity of a powder was determined mainly by the grain conductivity and the grain contact conductivity. The present results of impedance spectroscopy suggested that the grain contact resistance was a major factor of the electrical resistance of the samples. The aging effect at different moisture conditions was also caused by an increase of the contact resistance. Both sodium-doped and reduced titanium oxides showed re-oxidation at elevated temperature (above 140°C) in air, which is most probably caused by oxidizing the Ti3+ ions under those conditions. Lithium doped titanium oxides did not show this re-oxidation at temperatures up to 200°C. Theoretical models were applied to describe the effects of porosity, contact configuration and grain surface on conductivity of powder compacts. Percolation theory was used in the present study to demonstrate the effect of mixtures of conductive and non-conductive powders, which is one of applications for conductive ceramic powders when they are used as filler materials in paper, paints or plastics.

  2. Air Abrasion

    MedlinePlus

    ... delivered directly to your desktop! more... What Is Air Abrasion? Article Chapters What Is Air Abrasion? What Happens? The Pros and Cons Will I Feel Anything? Is Air Abrasion for Everyone? print full article print this ...

  3. Determination of the diffusion coefficient of protons in Nafion thin films by ac-electrogravimetry.

    PubMed

    Sel, Ozlem; To Thi Kim, L; Debiemme-Chouvy, Catherine; Gabrielli, Claude; Laberty-Robert, Christel; Perrot, Hubert

    2013-11-12

    This letter deals with an adaptation of the ac-electrogravimetry technique to extract separately the dynamic properties of H(+) and water in Nafion nanometric thin films (average thickness of 400 nm). An original theoretical approach was developed to extract the representative parameters from ac-electrogravimetry data. The concentration change of the exchanged species and the diffusion coefficient of the protons in a Nafion nanometric thin film (D = 0.5 × 10(-6) cm(2) s(-1) at 0.3 V vs SCE) were estimated for the first time according to the applied potential. The conductivity value of Nafion thin films was calculated from the Nernst-Einstein equation using diffusion coefficients and concentration values extracted from ac-electrogravimetry data. The calculated conductivity results agree well with the experimental proton conductivity values of Nafion thin films. PMID:24131383

  4. 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.

  5. 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. PMID:26364875

  6. Cartilage conduction hearing.

    PubMed

    Shimokura, Ryota; Hosoi, Hiroshi; Nishimura, Tadashi; Yamanaka, Toshiaki; Levitt, Harry

    2014-04-01

    Sound information is known to travel to the cochlea via either air or bone conduction. However, a vibration signal, delivered to the aural cartilage via a transducer, can also produce a clearly audible sound. This type of conduction has been termed "cartilage conduction." The aural cartilage forms the outer ear and is distributed around the exterior half of the external auditory canal. In cartilage conduction, the cartilage and transducer play the roles of a diaphragm and voice coil of a loudspeaker, respectively. There is a large gap between the impedances of cartilage and skull bone, such that cartilage vibrations are not easily transmitted through bone. Thus, these methods of conduction are distinct. In this study, force was used to apply a transducer to aural cartilage, and it was found that the sound in the auditory canal was amplified, especially for frequencies below 2 kHz. This effect was most pronounced at an application force of 1 N, which is low enough to ensure comfort in the design of hearing aids. The possibility of using force adjustments to vary amplification may also have applications for cell phone design.

  7. An Optimized Air-Core Coil Sensor with a Magnetic Flux Compensation Structure Suitable to the Helicopter TEM System

    PubMed Central

    Chen, Chen; Liu, Fei; Lin, Jun; Zhu, Kaiguang; Wang, Yanzhang

    2016-01-01

    The air-core coil sensor (ACS) is widely used as a transducer to measure the variation in magnetic fields of a helicopter transient electromagnetic (TEM) system. A high periodic emitting current induces the magnetic field signal of the underground medium. However, such current also generates a high primary field signal that can affect the received signal of the ACS and even damage the receiver. To increase the dynamic range of the received signal and to protect the receiver when emitting current rises/falls, the combination of ACS with magnetic flux compensation structure (bucking coil) is necessary. Moreover, the optimized ACS, which is composed of an air-core coil and a differential pre-amplifier circuit, must be investigated to meet the requirements of the helicopter TEM system suited to rapid surveying for shallow buried metal mine in rough topography. Accordingly, two ACSs are fabricated in this study, and their performance is verified and compared inside a magnetic shielding room. Using the designed ACSs, field experiments are conducted in Baoqing County. The field experimental data show that the primary field response can be compensated when the bucking coil is placed at an appropriate point in the range of allowed shift distance beyond the center of the transmitting coil and that the damage to the receiver induced by the over-statured signal can be solved. In conclusion, a more suitable ACS is adopted and is shown to have better performance, with a mass of 2.5 kg, resultant effective area of 11.6 m2 (i.e., diameter of 0.496 m), 3 dB bandwidth of 66 kHz, signal-to-noise ratio of 4 (i.e., varying magnetic field strength of 0.2 nT/s), and normalized equivalent input noise of 3.62 nV/m2. PMID:27077862

  8. AIR STRUCTURES FOR SCHOOL SPORTS.

    ERIC Educational Resources Information Center

    ROBERTSON, NAN

    AIR STRUCTURES ARE FABRIC BUILDINGS BLOWN UP AND HELD UP BY AIR PRESSURE. EXPERIMENTS WITH SUCH STRUCTURES WERE CONDUCTED AS EARLY AS 1917. IN 1948 THE UNITED STATES AIR FORCE SOUGHT A NEW WAY OF HOUSING LARGE RADAR ANTENNAE PLANNED FOR THE ARCTIC. AS AN OUTCOME OF THEIR SEARCH, BIRDAIR STRUCTURES, INC., WHICH IS NOW ONE OF SEVERAL COMPANIES…

  9. Air Structures for School Sports.

    ERIC Educational Resources Information Center

    Robertson, Nan

    Air structures are fabric buildings blown up and held up by air pressure. Experiments with such structures were conducted as early as 1917. In 1948 the United States Air Force sought a new way of housing large radar antennae planned for the arctic. As an outcome of their search, Birdair Structures, Inc., which is now one of several companies…

  10. 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.

  11. 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.

  12. Breakthrough Video: Desiccant Enhanced Evaporative Air Conditioning

    SciTech Connect

    2012-01-01

    Researchers at the National Renewable Energy Laboratory (NREL) invented a breakthrough technology that improves air conditioning in a novel way—with heat. NREL combined desiccant materials, which remove moisture from the air using heat, and advanced evaporative technologies to develop a cooling unit that uses 90% less electricity and up to 80% less total energy than traditional air conditioning (AC). This solution, called the desiccant enhanced evaporative air conditioner (DEVAP), also controls humidity more effectively to improve the comfort of people in buildings.

  13. Superconductor coil geometry and ac losses

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  14. 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.

  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. 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.

  17. 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.

  18. Impact of Solar Control PVB Glass on Vehicle Interior Temperatures, Air-Conditioning Capacity, Fuel Consumption, and Vehicle Range

    SciTech Connect

    Rugh, J.; Chaney, L.; Venson, T.; Ramroth, L.; Rose, M.

    2013-04-01

    The objective of the study was to assess the impact of Saflex1 S-series Solar Control PVB (polyvinyl butyral) configurations on conventional vehicle fuel economy and electric vehicle (EV) range. The approach included outdoor vehicle thermal soak testing, RadTherm cool-down analysis, and vehicle simulations. Thermal soak tests were conducted at the National Renewable Energy Laboratory's Vehicle Testing and Integration Facility in Golden, Colorado. The test results quantified interior temperature reductions and were used to generate initial conditions for the RadTherm cool-down analysis. The RadTherm model determined the potential reduction in air-conditioning (A/C) capacity, which was used to calculate the A/C load for the vehicle simulations. The vehicle simulation tool identified the potential reduction in fuel consumption or improvement in EV range between a baseline and modified configurations for the city and highway drive cycles. The thermal analysis determined a potential 4.0% reduction in A/C power for the Saflex Solar PVB solar control configuration. The reduction in A/C power improved the vehicle range of EVs and fuel economy of conventional vehicles and plug-in hybrid electric vehicles.

  19. 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.

  20. Tevatron optics measurements using an AC dipole

    SciTech Connect

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

    2007-06-01

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

  1. 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

  2. Indoor Air Quality in Brazilian Universities

    PubMed Central

    Jurado, Sonia R.; Bankoff, Antônia D. P.; Sanchez, Andrea

    2014-01-01

    This study evaluated the indoor air quality in Brazilian universities by comparing thirty air-conditioned (AC) (n = 15) and naturally ventilated (NV) (n = 15) classrooms. The parameters of interest were indoor carbon dioxide (CO2), temperature, relative humidity (RH), wind speed, viable mold, and airborne dust levels. The NV rooms had larger concentration of mold than the AC rooms (1001.30 ± 125.16 and 367.00 ± 88.13 cfu/m3, respectively). The average indoor airborne dust concentration exceeded the Brazilian standards (<80 μg/m3) in both NV and AC classrooms. The levels of CO2 in the AC rooms were significantly different from the NV rooms (1433.62 ± 252.80 and 520.12 ± 37.25 ppm, respectively). The indoor air quality in Brazilian university classrooms affects the health of students. Therefore, indoor air pollution needs to be considered as an important public health problem. PMID:25019268

  3. Dynamic conductance in L-shaped graphene nanosystems

    SciTech Connect

    Ye, En-Jia Nie, Yanguang; Shi, Haifeng; Zhang, Chengliang; Zhao, Xuean

    2015-01-07

    Dynamic conductance of nanocircuit, which demonstrates dc and ac transport properties, is regarded as vital indicator for device feature. With the help of nonequilibrium Green's function technology and Buttiker's ac transport theory, we present dynamic conductance in L-shaped graphene nanosystems (LGNSs). It is found that electronic transport is highly sensitive to the geometric feature as well as the size of LGNSs. The armchair edge lead determines whether LGNS shows ac response or not around Dirac point. The increase of width of zigzag edge lead suppresses dc conductance and induces capacitive responses at the anti-resonance states. This is due to large dwell time originated from edge state in zigzag edge lead. In the energy region far away from Dirac point, LGNS responds inductively with the transportation channel opens. Behaviors of dynamic conductance at Dirac point and anti-resonance states are discussed by interesting spacial-resolved local density of states.

  4. Dynamic conductance in L-shaped graphene nanosystems

    NASA Astrophysics Data System (ADS)

    Ye, En-Jia; Nie, Yanguang; Shi, Haifeng; Zhang, Chengliang; Zhao, Xuean

    2015-01-01

    Dynamic conductance of nanocircuit, which demonstrates dc and ac transport properties, is regarded as vital indicator for device feature. With the help of nonequilibrium Green's function technology and Buttiker's ac transport theory, we present dynamic conductance in L-shaped graphene nanosystems (LGNSs). It is found that electronic transport is highly sensitive to the geometric feature as well as the size of LGNSs. The armchair edge lead determines whether LGNS shows ac response or not around Dirac point. The increase of width of zigzag edge lead suppresses dc conductance and induces capacitive responses at the anti-resonance states. This is due to large dwell time originated from edge state in zigzag edge lead. In the energy region far away from Dirac point, LGNS responds inductively with the transportation channel opens. Behaviors of dynamic conductance at Dirac point and anti-resonance states are discussed by interesting spacial-resolved local density of states.

  5. Treatment of refractory nano-filtration reject from a tannery using Pd-catalyzed wet air oxidation.

    PubMed

    Tripathi, Pranav K; Rao, Nageswara N; Chauhan, Chetan; Pophali, Girish R; Kashyap, Sanjay M; Lokhande, Satish K; Gan, Lihua

    2013-10-15

    We attempted catalytic wet air oxidation (CWAO) of nanofiltration (NF)-reject using Pd based catalyst viz., Pd/activated charcoal (AC) and PdCl2 with the objective of degradation of refractory organic pollutants. Refractory organic pollutants in NF-reject before and after WAO and CWAO were confirmed by GC-MS analysis. Experiments were conducted to investigate the effects of temperature, catalyst dosage and air partial pressure on the rate of removal of total organic carbon (TOC). The reaction kinetics can be conveniently described by considering two-stage first order kinetics. The use of Pd/AC afforded 85% TOC removal, the corresponding rate constant (k) was 2.90 ± 0.075 × 10(-3)min(-1) (Pd/AC, 100mg/L; T, 473.15K; Pair, 0.69 MPa). On the other hand, 75% TOC was removed with k=2.31 ± 0.075 × 10(-3)min(-1) using Pd(2+) catalyst (Pd(2+), 16.66 mg/L; T, 473.15K; Pair, 0.69 MPa). The observed rate of mineralization under Pd-catalyzed conditions was significantly higher than that of the uncatalyzed oxidation (41%) under the similar experimental conditions. Catalyst stability experiments were performed and TEM, SEM, XRD, Raman and XPS characterization data collected. Despite some morphological transformation of support, Pd catalyst was stable under CWAO conditions.

  6. 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}.

  7. Ac losses for the self field of an ac transport current with a dc transport current offset in high {Tc} superconducting magnet coils for MagLev application

    SciTech Connect

    Koosh, V.F.

    1993-10-01

    Although much research has been conducted concerning the losses of high-{Tc} superconductors, very little has concentrated on the self-field losses in an actual magnet arrangement. The coils studied in this work were designed for use as actual magnets in an industrial application. Self field loss measurements were made upon tape-wound 2223 superconducting helix coils. The self-field losses were produced by an AC transport current with a DC transport current offset. Losses were taken for single, double and triple tape windings, giving essentially monofilament, dual, and three filament cases. The losses measured here were varied over a range of AC current values for several different DC values, and over a range of frequencies. The currents were all AC sinusoids with a DC offset. All measurements were made at T = 77K.

  8. Pressures in the human cochlea during bone conduction

    NASA Astrophysics Data System (ADS)

    Stieger, Christof; Farahmand, Rosemary B.; Page, Brent F.; Roushan, Kourosh; Merchant, Julie P.; Abur, Defne; Rosowski, John J.; Nakajima, Hideko Heidi

    2015-12-01

    The mechanisms of bone conduction (BC) hearing, which is important in diagnosis and treatment of hearing loss, are poorly understood, thus limiting use of BC. Recently, information gained by intracochlear pressure measurements has revealed that the mechanisms of sound transmission that drive pressure differences across the cochlear partition are different for air conduction (AC) than for round-window stimulation. Presently we are utilizing these pressure measurement techniques in fresh human cadaveric preparations to improve our understanding of sound transmission during BC. We have modified our technique of intracochlear pressure measurements for the special requirements of studying BC, as bone vibration poses challenges for making these measurements. Fiberoptic pressure sensors were inserted through cochleostomies in both scalae at the base of the cochlea. The cochleostomies were then tightly sealed with the sensors in place to prevent air and fluid leaks, and the sensors were firmly secured to ensure uniform vibrations of the sensors and surrounding bone of the cochlea. The velocity of the stapes, round window and cochlear promontory were each measured with laser Doppler vibrometry simultaneous to the intracochlear pressure measurements. To understand the contribution of middle-ear inertia, the incudo-stapedial joint was severed. Subsequently, the stapes footplate was fixed (similar to the consequence of otosclerosis) to determine the effect of removing the mobility of the oval window. BC stimulation resulted in pressure in scala vestibuli that was significantly higher than in scala tympani, such that the differential pressure across the partition - the cochlear drive input - was similar to scala vestibuli pressure (and overall, similar to the relationship found during AC but different than during round-window stimulation). After removing the inertial mass of the middle ear, with only the stapes attached to the flexible oval window, all pressures dropped

  9. Numeric description of space charge in polyethylene under ac electric fields

    NASA Astrophysics Data System (ADS)

    Zhao, J.; Xu, Z.; Chen, G.; Lewin, P. L.

    2010-12-01

    Space charge in polyethylene-based insulation materials and its effect on the local electric field under a dc environment have been extensively examined over the last few decades while the behavior of space charge under ac stress has received less attention. Space charge phenomenon under ac electric fields becomes an important issue with increased operating field strength in many applications, such as next generation high voltage cables. In this paper, a bipolar charge transport model has been developed to simulate space charge in polymers under ac electric fields. Obtained simulation results show that there is a small quantity of phase-dependent bipolar charge accumulation in the vicinity of the electrodes that does not move into the bulk under ac stress. This causes a slight distortion of the local field in the bulk. However, at lower frequencies less than 1 Hz, there is increased charge accumulation and penetration. Comparison with available experimental data suggests that the model is capable of describing the underlying physics of charge behavior when a dielectric material is subjected to ac electric fields. Due to the weak charge movement in the bulk, the conduction current density is small and hence the displacement component dominates the total current density and this increases linearly with ac frequency.

  10. Conducting polymers. VI. Effect of doping with iodine on the dielectrical and electrical conduction properties of polyacrylonitrile

    NASA Astrophysics Data System (ADS)

    El-Ghamaz, N. A.; Diab, M. A.; Zoromba, M. Sh.; El-Sonbati, A. Z.; El-Shahat, O.

    2013-10-01

    The effect of doping of polyacrylonitrile (PAN) with iodine on the dielectical properties and ac conductivity as a function of temperature and frequency is investigated. Thermogravimetric analysis, TGA, and FTIR measurements show that PAN undergoes degradation starting at 523 K. Doping PAN with I2 enhances the ac electrical conductivity σac in the temperature range under investigation due to oligomerization of the nitrile groups giving a conjugated polyimine. The thermal activation energy, ΔE, is calculated for PAN and PAN/I2 and found to be in the range 0.16-1.16 eV at 0.1 kHz. The correlated barrier hopping (CBH) conduction mechanism is found to be the dominant conduction mechanism for PAN and PAN/I2 samples.

  11. 78 FR 39345 - ACS Wireless, Inc.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-01

    ... COMMISSION ACS Wireless, Inc.; Notice of Application AGENCY: Securities and Exchange Commission (``Commission...''). Summary of Application: ACS Wireless, Inc. (``ACS Wireless'') seeks an order under section 3(b)(2) of the..., owning, holding or trading in securities. ACS Wireless is primarily engaged in providing...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. Baseline susceptibility to Cry1Ac insecticidal protein in Heliothis virescens (Lepidoptera: Noctuidae) populations in Brazil.

    PubMed

    Albernaz, K C; Merlin, B L; Martinelli, S; Head, G P; Omoto, C

    2013-08-01

    The tobacco budworm, Heliothis virescens (F.), is one of the target pests of genetically modified cotton expressing Cry1Ac insecticidal protein (Bt cotton) derived from Bacillus thuringiensis Berliner. This study was conducted to evaluate the susceptibility of field-collected populations of H. virescens to Cry1Ac to establish a baseline for use in an insect resistance management program for Bt cotton in Brazil. Insects were sampled from the main Brazilian cotton-growing regions (Bahia, Mato Grosso, Mato Grosso do Sul, and Goiás) during the cropping seasons of 2007/08 and 2008/09. Cry1Ac susceptibility was estimated by using diet incorporation bioassays. H. virescens was highly susceptible to Cry1Ac protein. The estimated LC50 values varied from 0.18 to 0.66 microg of Cry1Ac/ml of diet among the 2007-2008 populations (approximately 3.7-fold variation). Similarly, the EC50 values based on growth inhibition ranged from 0.0053 to 0.0161 microg of Cry1Ac/ml of diet for the 2007-2008 populations (approximately 3.0-fold variation). A joint analysis of the mortality data across all tested populations was used to develop and validate the diagnostic concentrations of 3.1 and 5.6 microg of Cry1Ac/ml of diet, the upper bound of the confidence interval and twice the LC99 were selected, for resistance monitoring programs of H. virescens to Cry1Ac protein in Brazil.

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

    SciTech Connect

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

    2013-05-01

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

  2. [Air conditioning units and warm air blankets in the operating room].

    PubMed

    Kerwat, Klaus; Piechowiak, Karolin; Wulf, Hinnerk

    2013-01-01

    Nowadays almost all operating rooms are equipped with air conditioning (AC units). Their main purpose is climatization, like ventilation, moisturizing, cooling and also the warming of the room in large buildings. In operating rooms they have an additional function in the prevention of infections, especially the avoidance of postoperative wound infections. This is achieved by special filtration systems and by the creation of specific air currents. Since hypothermia is known to be an unambiguous factor for the development of postoperative wound infections, patients are often actively warmed intraoperatively using warm air blankets (forced-air warming units). In such cases it is frequently discussed whether such warm air blankets affect the performance of AC units by changing the air currents or whether, in contrast, have exactly the opposite effect. However, it has been demonstrated in numerous studies that warm air blankets do not have any relevant effect on the functioning of AC units. Also there are no indications that their use increases the rate of postoperative wound infections. By preventing the patient from experiencing hypothermia, the rate of postoperative wound infections can even be decreased thereby.

  3. Air heating system

    DOEpatents

    Primeau, John J.

    1983-03-01

    A self-starting, fuel-fired, air heating system including a vapor generator, a turbine, and a condenser connected in a closed circuit such that the vapor output from the vapor generator is conducted to the turbine and then to the condenser where it is condensed for return to the vapor generator. The turbine drives an air blower which passes air over the condenser for cooling the condenser. Also, a condensate pump is driven by the turbine. The disclosure is particularly concerned with the provision of heat exchanger and circuitry for cooling the condensed fluid output from the pump prior to its return to the vapor generator.

  4. Development of a Bone-Conducted Ultrasonic Hearing Aid for the Profoundly Deaf: Evaluation of Sound Quality Using a Semantic Differential Method

    NASA Astrophysics Data System (ADS)

    Nakagawa, Seiji; Fujiyuki, Chika; Kagomiya, Takayuki

    2013-07-01

    Bone-conducted ultrasound (BCU) is perceived even by the profoundly sensorineural deaf. A novel hearing aid using the perception of amplitude-modulated BCU (BCU hearing aid: BCUHA) has been developed. However, there is room for improvement particularly in terms of sound quality. BCU speech is accompanied by a strong high-pitched tone and contain some distortion. In this study, the sound quality of BCU speech with several types of amplitude modulation [double-sideband with transmitted carrier (DSB-TC), double-sideband with suppressed carrier (DSB-SC), and transposed modulations] and air-conducted (AC) speech was quantitatively evaluated using semantic differential and factor analysis. The results showed that all the types of BCU speech had higher metallic and lower esthetic factor scores than AC speech. On the other hand, transposed speech was closer than the other types of BCU speech to AC speech generally; the transposed speech showed a higher powerfulness factor score than the other types of BCU speech and a higher esthetic factor score than DSB-SC speech. These results provide useful information for further development of the BCUHA.

  5. Air breathing direct methanol fuel cell

    DOEpatents

    Ren, Xiaoming; Gottesfeld, Shimshon

    2002-01-01

    An air breathing direct methanol fuel cell is provided with a membrane electrode assembly, a conductive anode assembly that is permeable to air and directly open to atmospheric air, and a conductive cathode assembly that is permeable to methanol and directly contacting a liquid methanol source. Water loss from the cell is minimized by making the conductive cathode assembly hydrophobic and the conductive anode assembly hydrophilic.

  6. Mercury and Air Toxic Element Impacts of Coal Combustion By-Product Disposal and Utilizaton

    SciTech Connect

    David Hassett; Loreal Heebink; Debra Pflughoeft-Hassett; Tera Buckley; Erick Zacher; Mei Xin; Mae Sexauer Gustin; Rob Jung

    2007-03-31

    The University of North Dakota Energy & Environmental Research Center (EERC) conducted a multiyear study to evaluate the impact of mercury and other air toxic elements (ATEs) on the management of coal combustion by-products (CCBs). The ATEs evaluated in this project were arsenic, cadmium, chromium, lead, nickel, and selenium. The study included laboratory tasks to develop measurement techniques for mercury and ATE releases, sample characterization, and release experiments. A field task was also performed to measure mercury releases at a field site. Samples of fly ash and flue gas desulfurization (FGD) materials were collected preferentially from full-scale coal-fired power plants operating both without and with mercury control technologies in place. In some cases, samples from pilot- and bench-scale emission control tests were included in the laboratory studies. Several sets of 'paired' baseline and test fly ash and FGD materials collected during full-scale mercury emission control tests were also included in laboratory evaluations. Samples from mercury emission control tests all contained activated carbon (AC) and some also incorporated a sorbent-enhancing agent (EA). Laboratory release experiments focused on measuring releases of mercury under conditions designed to simulate CCB exposure to water, ambient-temperature air, elevated temperatures, and microbes in both wet and dry conditions. Results of laboratory evaluations indicated that: (1) Mercury and sometimes selenium are collected with AC used for mercury emission control and, therefore, present at higher concentrations than samples collected without mercury emission controls present. (2) Mercury is stable on CCBs collected from systems both without and with mercury emission controls present under most conditions tested, with the exception of vapor-phase releases of mercury exposed to elevated temperatures. (3) The presence of carbon either from added AC or from unburned coal can result in mercury being

  7. Deletion of AcMNPV ac146 eliminates the production of budded virus.

    PubMed

    Dickison, Virginia L; Willis, Leslie G; Sokal, Nadia R; Theilmann, David A

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac146 is a highly conserved gene in the Alpha- and Betabaculovirus genera that has an unknown function. Northern blot analysis and transcript mapping showed that ac146 is transcribed at late times post infection as a 1.2 kb mRNA. To determine the role of ac146 in the baculovirus life cycle ac146 knock out viruses were constructed. Transfection and plaque assays showed that all the ac146 deletions produced a single cell phenotype indicating that no infectious budded virus (BV) was produced, however occlusion bodies were formed. The lack of BV production was confirmed by viral titration utilizing both qPCR and TCID₅₀. Analysis of BV and occlusion derived virus (ODV) revealed that AC146 is associated with both forms of the virus and is modified specifically in ODV. This study therefore demonstrates that AC146 is a late virion associated protein and is essential for the viral life cycle.

  8. Air breathing direct methanol fuel cell

    DOEpatents

    Ren, Xiaoming

    2002-01-01

    An air breathing direct methanol fuel cell is provided with a membrane electrode assembly, a conductive anode assembly that is permeable to air and directly open to atmospheric air, and a conductive cathode assembly that is permeable to methanol and directly contacting a liquid methanol source.

  9. Microfluidic flow-focusing in ac electric fields.

    PubMed

    Tan, Say Hwa; Semin, Benoît; Baret, Jean-Christophe

    2014-03-21

    We demonstrate the control of droplet sizes by an ac voltage applied across microelectrodes patterned around a flow-focusing junction. The electrodes do not come in contact with the fluids to avoid electrochemical effects. We found several regimes of droplet production in electric fields, controlled by the connection of the chip, the conductivity of the dispersed phase and the frequency of the applied field. A simple electrical modelling of the chip reveals that the effective voltage at the tip of the liquid to be dispersed controls the production mechanism. At low voltages (≲ 600 V), droplets are produced in dripping regime; the droplet size is a function of the ac electric field. The introduction of an effective capillary number that takes into account the Maxwell stress can explain the dependance of droplet size with the applied voltage. At higher voltages (≳ 600 V), jets are observed. The stability of droplet production is a function of the fluid conductivity and applied field frequency reported in a set of flow diagrams. PMID:24401868

  10. Cyclotron and linac production of Ac-225.

    PubMed

    Melville, Graeme; Allen, Barry J

    2009-04-01

    Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. The reduction of radium by photonuclear transmutation by bombarding Ra-226 with high-energy photons from a medical linear accelerator (linac) has been investigated. A linac dose of 2800 Gy produced about 2.4 MBq (64 microCi) of Ra-225, which decays to Ac-225 and can then be used for 'Targeted Alpha Therapy' (TAT) of cancer. This result, while consistent with theoretical calculations, is far too low to be of practical use unless much larger quantities of radium are irradiated. The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. This paper investigates the possibility of producing of Ac-225 in commercial quantities, which could potentially reduce obsolete radioactive material and displace the need for expensive importation of Ac-225 from the USA and Russia in the years ahead. Scaled up production of Ac-225 could theoretically be achieved by the use of a high current cyclotron or linac. Production specifications are determined for a linac in terms of current, pulse length and frequency, as well as an examination of other factors such as radiation issues and radionuclei separation. Yields are compared with those calculated for the Australian National Cyclotron in Sydney.

  11. Design and synthesis of 225Ac radioimmunopharmaceuticals.

    PubMed

    McDevitt, Michael R; Ma, Dangshe; Simon, Jim; Frank, R Keith; Scheinberg, David A

    2002-12-01

    The alpha-particle-emitting radionuclides 213Bi, 211At, 224Ra are under investigation for the treatment of leukemias, gliomas, and ankylosing spondylitis, respectively. 213Bi and 211At were attached to monoclonal antibodies and used as targeted immunotherapeutic agents while unconjugated 224Ra chloride selectively seeks bone. 225Ac possesses favorable physical properties for radioimmunotherapy (10d half-life and 4 net alpha particles), but has a history of unfavorable radiolabeling chemistry and poor metal-chelate stability. We selected functionalized derivatives of DOTA as the most promising to pursue from out of a group of potential 225Ac chelate compounds. A two-step synthetic process employing either MeO-DOTA-NCS or 2B-DOTA-NCS as the chelating moiety was developed to attach 225Ac to monoclonal antibodies. This method was tested using several different IgG systems. The chelation reaction yield in the first step was 93+/-8% radiochemically pure (n=26). The second step yielded 225Ac-DOTA-IgG constructs that were 95+/-5% radiochemically pure (n=27) and the mean percent immunoreactivity ranged from 25% to 81%, depending on the antibody used. This process has yielded several potential novel targeted 225Ac-labeled immunotherapeutic agents that may now be evaluated in appropriate model systems and ultimately in humans.

  12. Cosmic Shear - with ACS Pure Parallel Observations

    NASA Astrophysics Data System (ADS)

    Ratnatunga, Kavan

    2002-07-01

    The ACS, with greater sensitivity and sky coverage, will extend our ability to measure the weak gravitational lensing of galaxy images caused by the large scale distribution of dark matter. We propose to use the ACS in pure parallel {non- proprietary} mode, following the guidelines of the ACS Default Pure Parallel Program. Using the HST Medium Deep Survey WFPC2 database we have measured cosmic shear at arc-min angular scales. The MDS image parameters, in particular the galaxy orientations and axis ratios, are such that any residual corrections due to errors in the PSF or jitter are much smaller than the measured signal. This situation is in stark contrast with ground-based observations. We have also developed a statistical analysis procedure to derive unbiased estimates of cosmic shear from a large number of fields, each of which has a very small number of galaxies. We have therefore set the stage for measurements with the ACS at fainter apparent magnitudes and smaller, 10 arc-second scales corresponding to larger cosmological distances. We will adapt existing MDS WFPC2 maximum likelihood galaxy image analysis algorithms to work with the ACS. The analysis would also yield an online database similar to that in archive.stsci.edu/mds/

  13. Electrochemical corrosion studies in low conductivity propellants

    NASA Technical Reports Server (NTRS)

    Blue, G. D.; Moran, C. M.; Distefano, S.

    1986-01-01

    The Jet Propulsion Laboratory is investigating the possibility of developing advanced electrochemical techniques as accelerated compatibility tests for metal/propellant systems which overcome the problems associated with the low conductivity of the liquid propellants (e.g., hydrazines, nitrogen tetroxide). Both DC techniques and AC electrochemical impedance spectroscopy are being evaluated. Progress has been made in experiments involving stainless steel with hydrazine and nitrogen tetroxide propellants.

  14. Air resources

    SciTech Connect

    1995-10-01

    This section describes the ambient (surrounding) air quality of the TVA region, discusses TVA emission contributions to ambient air quality, and identifies air quality impacts to human health and welfare. Volume 2 Technical Document 2, Environmental Consequences, describes how changes in TVA emissions could affect regional air quality, human health, environmental resources, and materials. The primary region of the affected environment is broadly defined as the state of Tennessee, as well as southern Kentucky, western Virginia, southern West Virginia, western North Carolina, and northern Georgia, Alabama, and Mississippi. This area represents the watershed of the Tennessee River and the 201 counties of the greater TVA service area. Emissions from outside the Tennessee Valley region contribute to air quality in the Valley. Also, TVA emissions are transported outside the Valley and have some impact on air quality beyond the primary study area. Although the study area experiences a number of air quality problems, overall air quality is good.

  15. Cyclic stress-strain curve determination for D6AC steel by three methods

    NASA Technical Reports Server (NTRS)

    Nachtigall, A. J.

    1977-01-01

    The room temperature cyclic stress-strain was determined for D6AC low alloy steel by three different methods. The method that involves the use of a single specimen monotonic tension test after cyclic straining provided the best agreement with the accepted basic method which requires a number of companion specimen tests. The single specimen test is also the simplest to conduct.

  16. Electrically conductive and thermally conductive materials for electronic packaging

    NASA Astrophysics Data System (ADS)

    Liu, Zongrong

    The aim of this dissertation is to develop electrically or thermally conductive materials that are needed for electronic packaging and microelectronic cooling. These materials are in the form of coatings and are made from pastes. The research work encompasses paste formulation, studying the process of converting a paste to a conductive material, relating the processing conditions to the structure and performance, and evaluating performance attributes that are relevant to the application of these conductive materials. The research has resulted in new information that is valuable to the microelectronic industry. Work on electrically conductive materials emphasizes the development of electrical interconnection materials in the form of air-firable glass-free silver-based electrically conductive thick films, which use the Ti-Al alloy as the binder and are in contrast to conventional films that use glass as the binder. The air-firability, as enabled by minor additions of tin and zinc to the paste, is in contrast to previous glass-free films that are not firable. The recommended firing condition is 930°C in air. The organic vehicle in the paste comprises ethyl cellulose, which undergoes thermal decomposition during burnout of the paste. The ethyl cellulose is dissolved in ether, which facilitates the burnout. Excessive ethyl cellulose hinders the burnout. A higher heating rate results in more residue after burnout. The presence of silver particles facilitates drying and burnout. Firing in air gives lower resistivity than firing in oxygen. Firing in argon gives poor films. Compared to conventional films that use glass as the binder, these films, when appropriately fired, exhibit lower electrical resistivity (2.5 x 10-6 O.cm) and higher scratch resistance. Work on thermally conductive materials addresses thermal interface materials, which are materials placed at the interface between a heat sink and a heat source for the purpose of improving the thermal contact. Heat

  17. Air Pollution.

    ERIC Educational Resources Information Center

    Gilpin, Alan

    A summary of one of our most pressing environmental problems, air pollution, is offered in this book by the Director of Air Pollution Control for the Queensland (Australia) State Government. Discussion of the subject is not restricted to Queensland or Australian problems and policies, however, but includes analysis of air pollution the world over.…

  18. Room air monitor for radioactive aerosols

    DOEpatents

    Balmer, David K.; Tyree, William H.

    1989-04-11

    A housing assembly for use with a room air monitor for simultaneous collection and counting of suspended particles includes a casing containing a combination detector-preamplifier system at one end, a filter system at the other end, and an air flow system consisting of an air inlet formed in the casing between the detector-preamplifier system and the filter system and an air passageway extending from the air inlet through the casing and out the end opposite the detector-preamplifier combination. The filter system collects suspended particles transported directly through the housing by means of the air flow system, and these particles are detected and examined for radioactivity by the detector-pre The U.S. Government has rights in this invention pursuant to Contract No. DE-AC04-76DP03533 between the Department of Energy and Rockwell International Corporation.

  19. ac propulsion system for an electric vehicle

    NASA Technical Reports Server (NTRS)

    Geppert, S.

    1980-01-01

    It is pointed out that dc drives will be the logical choice for current production electric vehicles (EV). However, by the mid-80's, there is a good chance that the price and reliability of suitable high-power semiconductors will allow for a competitive ac system. The driving force behind the ac approach is the induction motor, which has specific advantages relative to a dc shunt or series traction motor. These advantages would be an important factor in the case of a vehicle for which low maintenance characteristics are of primary importance. A description of an EV ac propulsion system is provided, taking into account the logic controller, the inverter, the motor, and a two-speed transmission-differential-axle assembly. The main barrier to the employment of the considered propulsion system in EV is not any technical problem, but inverter transistor cost.

  20. Atrial-caval shunting (ACS) after trauma.

    PubMed

    Kudsk, K A; Sheldon, G F; Lim, R C

    1982-02-01

    Since 1968 the atrial-caval shunt (ACS), along with inflow occlusion at the porta hepatis, has been used at San Francisco General Hospital in 18 trauma patients to control massive hemorrhage from the inferior vena cava, hepatic veins, or liver. Thirteen patients died from irreversible shock. Five patients survived their initial injuries; one of them died 45 days later from the complications of shock and sepsis. No patients survived who sustained blunt trauma and were admitted in cardiac arrest. Only one of ten patients with BP less than 70 mm Hg after resuscitation survived, whereas four of eight with BP greater than 70 mm Hg survived. ACS was used to control caval injuries in seven patients (one survivor), severe hepatic parenchymal fractures in four patients (two survivors), and combined hepatic and caval injuries in seven patients (two survivors). Survivors had an average of 5.75 associated injuries; nonsurvivors had 3.8. No complications of ACS occurred in the surviving patients.

  1. Development of an in-line filter to prevent intrusion of NO2 toxic vapors into A/C systems

    NASA Technical Reports Server (NTRS)

    Meneghelli, Barry; Mcnulty, R. J.; Springer, Mike; Lueck, Dale E.

    1995-01-01

    The hypergolic propellant nitrogen tetroxide (N2O4 or NTO) is routinely used in spacecraft launched at Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS). In the case of a catastrophic failure of the spacecraft, there would be a release of the unspent propellant in the form of a toxic cloud. Inhalation of this material at downwind concentrations which may be as high as 20 parts per million (ppm) for 30 minutes in duration, may produce irritation to the eyes, nose and respiratory tract. Studies at both KSC and CCAS have shown that the indoor concentrations of N2O4 during a toxic release may range from 1 to 15 ppm and depend on the air change rate (ACR) for a particular building and whether or not the air conditioning (A/C) system has been shut down or left in an operating mode. This project was initiated in order to assess how current A/C systems could be easily modified to prevent personnel from being exposed to toxic vapors. A sample system has been constructed to test the ability of several types of filter material to capture the N2O4 vapors prior to their infiltration into the A/C system. Test results will be presented which compare the efficiencies of standard A/C filters, water wash systems, and chemically impregnated filter material in taking toxic vapors out of the incoming air stream.

  2. Beneficial Effects of Adenylyl Cyclase Type 6 (AC6) Expression Persist Using a Catalytically Inactive AC6 Mutant

    PubMed Central

    Tang, Tong; Lai, Ngai Chin; Miyanohara, Atsushi; Guo, Tracy; Tang, Rouying; Firth, Amy L.; Yuan, Jason X.; Hammond, H. Kirk

    2011-01-01

    Cardiac-directed expression of AC6 has pronounced favorable effects on cardiac function possibly not linked with cAMP production. To determine rigorously whether cAMP generation is required for the beneficial effects of increased AC6 expression, we generated a catalytically inactive AC6 mutant (AC6mut) that has markedly diminished cAMP generating capacity by replacing aspartic acid with alanine at position 426 in the C1 domain (catalytic region) of AC6. Gene transfer of AC6 or AC6mut (adenovirus-mediated) in adult rat cardiac myocytes resulted in similar expression levels and intracellular distribution, but AC6mut expression was associated with marked reduction in cAMP production. Despite marked reduction in cAMP generation, AC6mut influenced intracellular signaling events similarly to that observed after expression of catalytically intact AC6. For example, both AC6 and AC6mut reduced phenylephrine-induced cardiac myocyte hypertrophy and apoptosis (p < 0.001), expression of cardiac ankyrin repeat protein (p < 0.01), and phospholamban (p < 0.05). AC6mut expression, similar to its catalytically intact cohort, was associated with increased Ca2+ transients in cardiac myocytes after isoproterenol stimulation. Many of the biological effects of AC6 expression are replicated by a catalytically inactive AC6 mutant, indicating that the mechanisms for these effects do not require increased cAMP generation. PMID:21127130

  3. Kondo physics in the single-electron transistor with ac driving

    SciTech Connect

    Nordlander, Peter; Wingreen, Ned S.; Meir, Yigal; Langreth, David C.

    2000-01-15

    Using a time-dependent Anderson Hamiltonian, a quantum dot with an ac voltage applied to a nearby gate is investigated. A rich dependence of the linear response conductance on the external frequency and driving amplitude is demonstrated. At low frequencies a sufficiently strong ac potential produces sidebands of the Kondo peak in the spectral density of the dot, and a slow, roughly logarithmic decrease in conductance over several decades of frequency. At intermediate frequencies, the conductance of the dot displays an oscillatory behavior due to the appearance of Kondo resonances of the satellites of the dot level. At high frequencies, the conductance of the dot can vary rapidly due to the interplay between photon-assisted tunneling and the Kondo resonance. (c) 2000 The American Physical Society.

  4. Decommissioning of TA-21-153, a /sup 227/Ac contaminated old filter building

    SciTech Connect

    Harper, J.R.; Garde, R.

    1981-11-01

    An exhaust air filter building contaminated with /sup 227/Ac was decommissioned at the Los Alamos National Laboratory, Los Alamos, New Mexico, in 1978. The building was constructed in the late 1940s to clean exhaust air from several buildings at TA-21, DP Site. It was in service until March 1970. The project involved preliminary decontamination, dismantling the building, and burying the debris at an on-site waste disposal/storage area. This report presents the details on the decommissioning procedures, health physics, waste management, environmental surveillance, and costs for the operation.

  5. First thin AC-coupled silicon strip sensors on 8-inch wafers

    NASA Astrophysics Data System (ADS)

    Bergauer, T.; Dragicevic, M.; König, A.; Hacker, J.; Bartl, U.

    2016-09-01

    The Institute of High Energy Physics (HEPHY) in Vienna and the semiconductor manufacturer Infineon Technologies Austria AG developed a production process for planar AC-coupled silicon strip sensors manufactured on 200 μm thick 8-inch p-type wafers. In late 2015, the first wafers were delivered featuring the world's largest AC-coupled silicon strip sensors. Detailed electrical measurements were carried out at HEPHY, where single strip and global parameters were measured. Mechanical studies were conducted and the long-term behavior was investigated using a climate chamber. Furthermore, the electrical properties of various test structures were investigated to validate the quality of the manufacturing process.

  6. 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

  7. The Effects of AC Electromagnetic Stimuli in Conjunction with Standard Cryogenic Treatment of Metals

    NASA Astrophysics Data System (ADS)

    Seyfert, James; Evans, Austin; Leadlove, Kyle; Watson, Casey; Paulin, Peter; Peter Paulin Collaboration

    2016-03-01

    We explore modifications to the basic cryogenic procedures utilized by 300 Below Inc. to strengthen metal components. We consider the effects of adding AC electromagnetic stimuli in our efforts to further optimize the cryogenic treatment - i.e., to augment the already improved tensile strength, shear strength, thermal and electrical conductivity, etc. resulting from 300 Below Inc.'s traditional cryogenic process. We report on the wear-test performance of AC magneto-cryogenic treated samples relative to standard cryogenically treated samples and control samples. Replace this text with your abstract body.

  8. Community air monitoring and Village Green Project

    EPA Science Inventory

    Cost and logistics are practical issues that have historically constrained the number of locations where long-term, active air pollution measurement is possible. In addition, traditional air monitoring approaches are generally conducted by technical experts with limited engageme...

  9. Transient AC voltage related phenomena for HVDC schemes connected to weak AC systems

    SciTech Connect

    Pilotto, L.A.S.; Szechtman, M. ); Hammad, A.E. )

    1992-07-01

    In this paper a didactic explanation of voltage stability associated phenomena at HVDC terminals is presented. Conditions leading to ac voltage collapse problems are identified. A mechanism that excites control-induced voltage oscillations is shown. The voltage stability factor is used for obtaining the maximum power limits of ac/dc systems operating with different control strategies. Correlation to Pd {times} Id curves is given. Solutions for eliminating the risks of voltage collapse and for avoiding control-induced oscillations are discussed. The results are supported by detailed digital simulations of a weak ac/dc system using EMTP.

  10. AcsA-AcsB: The core of the cellulose synthase complex from Gluconacetobacter hansenii ATCC23769.

    PubMed

    McManus, John B; Deng, Ying; Nagachar, Nivedita; Kao, Teh-hui; Tien, Ming

    2016-01-01

    The gram-negative bacterium, Gluconacetobacter hansenii, produces cellulose of exceptionally high crystallinity in comparison to the cellulose of higher plants. This bacterial cellulose is synthesized and extruded into the extracellular medium by the cellulose synthase complex (CSC). The catalytic component of this complex is encoded by the gene AcsAB. However, several other genes are known to encode proteins critical to cellulose synthesis and are likely components of the bacterial CSC. We have purified an active heterodimer AcsA-AcsB from G. hansenii ATCC23769 to homogeneity by two different methods. With the purified protein, we have determined how it is post-translationally processed, forming the active heterodimer AcsA-AcsB. Additionally, we have performed steady-state kinetic studies on the AcsA-AcsB complex. Finally through mutagenesis studies, we have explored the roles of the postulated CSC proteins AcsC, AcsD, and CcpAx. PMID:26672449

  11. AcsA-AcsB: The core of the cellulose synthase complex from Gluconacetobacter hansenii ATCC23769.

    PubMed

    McManus, John B; Deng, Ying; Nagachar, Nivedita; Kao, Teh-hui; Tien, Ming

    2016-01-01

    The gram-negative bacterium, Gluconacetobacter hansenii, produces cellulose of exceptionally high crystallinity in comparison to the cellulose of higher plants. This bacterial cellulose is synthesized and extruded into the extracellular medium by the cellulose synthase complex (CSC). The catalytic component of this complex is encoded by the gene AcsAB. However, several other genes are known to encode proteins critical to cellulose synthesis and are likely components of the bacterial CSC. We have purified an active heterodimer AcsA-AcsB from G. hansenii ATCC23769 to homogeneity by two different methods. With the purified protein, we have determined how it is post-translationally processed, forming the active heterodimer AcsA-AcsB. Additionally, we have performed steady-state kinetic studies on the AcsA-AcsB complex. Finally through mutagenesis studies, we have explored the roles of the postulated CSC proteins AcsC, AcsD, and CcpAx.

  12. COMPUTATIONS ON THE PERFORMANCE OF PARTICLE FILTERS AND ELECTRONIC AIR CLEANERS

    EPA Science Inventory

    The paper discusses computations on the performance of particle filters and electronic air cleaners (EACs). The collection efficiency of particle filters and ACs is calculable if certain factors can be assumed or calibrated. For fibrous particulate filters, measurement of colle...

  13. Air encapsulation during infiltration

    USGS Publications Warehouse

    Constantz, J.; Herkelrath, W.N.; Murphy, F.

    1988-01-01

    A series of field and laboratory experiments were performed to measure the effects of air encapsulation within the soil's transmission zone upon several infiltration properties. In the field, infiltration rates were measured using a double-cap infiltrometer and soil-water contents were measured using time-domain reflectometry (TDR). In the laboratory, infiltration experiments were peformed using repacked soil columns using TDR and CO 2 flooding. Results suggest that a significant portion of the total encapsulated air resided in interconnected pores within the soil's transmission zone. For the time scale considered, this residual air caused the effective hydraulic conductivity of the transmission zone to remain at a level no greater than 20% of the saturated hydraulic conductivity of the soil. -from Authors

  14. 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.

  15. Ac-dc converter firing error detection

    SciTech Connect

    Gould, O.L.

    1996-07-15

    Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest harmonic components at maximum output. The 720 Hz harmonic is typically greater than 20 dB below the 500 VDC output signal under normal operation. Extracting specific harmonics from the rectifier output signal of a 6, 12, or 24 pulse ac-dc converter allows the detection of SCR firing angle errors or complete misfires. A bandpass filter provides the input signal to a frequency-to-voltage converter. Comparing the output of the frequency-to-voltage converter to a reference voltage level provides an indication of the magnitude of the harmonics in the ac-dc converter output signal.

  16. MY 20 YEARS EXPERIENCE IN CONDUCTING ENVIRONMENTAL HEALTH STUDIES IN CHINA: (1) STUDIES ON LUNG CANCER AND INDOOR AIR POLLUTION IN YUNNAN AND (2) HEALTH EFFECTS OF ARSENIC EXPOSURE VIA DRINKING WATER IN INNER MONGOLIA

    EPA Science Inventory

    As a research health scientist at U.S. Environmental Protection Agency, I have been very fortunate to have opportunities to work as a principal investigator for two major environmental health research projects. The first study was conducted in 1983-1996 under a formal U.S.-China ...

  17. Saccular function in otosclerosis patients: bone conducted-vestibular evoked myogenic potential analysis.

    PubMed

    Amali, Amin; Mahdi, Parvane; Karimi Yazdi, Alireza; Khorsandi Ashtiyani, Mohammad Taghi; Yazdani, Nasrin; Vakili, Varasteh; Pourbakht, Akram

    2014-01-01

    Vestibular involvements have long been observed in otosclerotic patients. Among vestibular structures saccule has the closest anatomical proximity to the sclerotic foci, so it is the most prone vestibular structure to be affected during the otosclerosis process. The aim of this study was to investigate the saccular function in patients suffering from otosclerosis, by means of Vestibular Evoked Myogenic Potential (VEMP). The material consisted of 30 otosclerosis patients and 20 control subjects. All participants underwent audiometric and VEMP testing. Analysis of tests results revealed that the mean values of Air-Conducted Pure Tone Average (AC-PTA) and Bone-Conducted Pure Tone Average (BC-PTA) in patients were 45.28 ± 15.57 and 19.68 ± 10.91, respectively and calculated 4 frequencies Air Bone Gap (ABG) was 25.64 ± 9.95. The VEMP response was absent in 14 (28.57%) otosclerotic ears. A statistically significant increase in latency of the p13 was found in the affected ears (P=0.004), differences in n23 latency did not reach a statistically significant level (P=0.112). Disparities in amplitude of p13-n23 in between two study groups was statistically meaningful (P=0.009), indicating that the patients with otosclerosis had lower amplitudes. This study tends to suggest that due to the direct biotoxic effect of the materials released from the otosclerosis foci on saccular receptors, there might be a possibility of vestibular dysfunction in otosclerotic patients. PMID:24659067

  18. Electrical conductivity of polyvinyl alcohol-multiwall carbon nanotubes composites

    NASA Astrophysics Data System (ADS)

    Amrin, Sayed; Deshpande, V. D.

    2013-06-01

    The dc and ac conductivity of polyvinyl alcohol (PVA)-multiwalled carbon nanotube (MWNT) nanocomposites prepared by solution casting were investigated by employing dielectric relaxation spectroscopy in broad frequency range (0.1 Hz-10 MHz) at room temperature as a function of the conductive weight fraction (p) ranging from 0 to 2wt.%. The frequency dependence of the measured conductivity obeys the universal dynamic response (UDR); a dc plateau followed, by the power law above a critical frequency (fc).

  19. Linear ac transport in graphene semiconducting nanosystem with normal-metal electrodes

    NASA Astrophysics Data System (ADS)

    Ye, En-Jia; Sun, Yun-Lei; Lan, Jin; Shi, Yi-Jian

    2016-03-01

    Linear ac transport properties are investigated in a graphene semiconducting nanosystem, with the effect of normal-metal electrodes taken into account. We use a tight-binding approach and ac transport theory to study the dc conductance and ac emittance in normal-metal/graphene (NG) and normal-metal/graphene/normal-metal (NGN) systems with armchair-edge graphene. We find that the resonant and semiconducting behaviors in NG and NGN systems are closely related to the spatial-resolved local density of states. Furthermore, features of the size-dependent emittances in the NGN system are investigated. The results suggest a positive correlation between the width and capacitive response, and the capacitive response is robust as the size of the system increases proportionally.

  20. Process air quality data

    NASA Technical Reports Server (NTRS)

    Butler, C. M.; Hogge, J. E.

    1978-01-01

    Air quality sampling was conducted. Data for air quality parameters, recorded on written forms, punched cards or magnetic tape, are available for 1972 through 1975. Computer software was developed to (1) calculate several daily statistical measures of location, (2) plot time histories of data or the calculated daily statistics, (3) calculate simple correlation coefficients, and (4) plot scatter diagrams. Computer software was developed for processing air quality data to include time series analysis and goodness of fit tests. Computer software was developed to (1) calculate a larger number of daily statistical measures of location, and a number of daily monthly and yearly measures of location, dispersion, skewness and kurtosis, (2) decompose the extended time series model and (3) perform some goodness of fit tests. The computer program is described, documented and illustrated by examples. Recommendations are made for continuation of the development of research on processing air quality data.

  1. Air Ground Integration Study

    NASA Technical Reports Server (NTRS)

    Lozito, Sandy; Mackintosh, Margaret-Anne; DiMeo, Karen; Kopardekar, Parimal

    2002-01-01

    A simulation was conducted to examine the effect of shared air/ground authority when each is equipped with enhanced traffic- and conflict-alerting systems. The potential benefits of an advanced air traffic management (ATM) concept referred to as "free flight" include improved safety through enhanced conflict detection and resolution capabilities, increased flight-operations management, and better decision-making tools for air traffic controllers and flight crews. One element of the free-flight concept suggests shifting aircraft separation responsibility from air traffic controllers to flight crews, thereby creating an environment with "shared-separation" authority. During FY00. NASA, the Federal Aviation Administration (FAA), and the Volpe National Transportation Systems Center completed the first integrated, high-fidelity, real-time, human-in-the-loop simulation.

  2. Measurement of volume resistivity/conductivity of metallic alloy in inhibited seawater by optical interferometry techniques

    SciTech Connect

    Habib, K.

    2011-03-15

    Optical interferometry techniques were used for the first time to measure the volume resistivity/conductivity of carbon steel samples in seawater with different concentrations of a corrosion inhibitor. In this investigation, the real-time holographic interferometry was carried out to measure the thickness of anodic dissolved layer or the total thickness, U{sub total}, of formed oxide layer of carbon steel samples during the alternating current (ac) impedance of the samples in blank seawater and in 5-20 ppm TROS C-70 inhibited seawater, respectively. In addition, a mathematical model was derived in order to correlate between the ac impedance (resistance) and the surface (orthogonal) displacement of the surface of the samples in solutions. In other words, a proportionality constant [resistivity ({rho}) or conductivity ({sigma})= 1/{rho}] between the determined ac impedance [by electrochemical impedance spectroscopy (EIS) technique] and the orthogonal displacement (by the optical interferometry techniques) was obtained. The value of the resistivity of the carbon steel sample in the blank seawater was found similar to the value of the resistivity of the carbon steel sample air, around 1 x 10{sup -5}{Omega} cm. On the contrary, the measured values of the resistivity of the carbon steel samples were 1.85 x 10{sup 7}, 3.35 x 10{sup 7}, and 1.7 x 10{sup 7}{Omega} cm in 5, 10, and 20 ppm TROS C-70 inhibited seawater solutions, respectively. Furthermore, the determined value range of {rho} of the formed oxide layers, from 1.7 x 10{sup 7} to 3.35 x 10{sup 7}{Omega} cm, is found in a reasonable agreement with the one found in literature for the Fe oxide-hydroxides, i.e., goethite ({alpha}-FeOOH) and for the lepidocrocite ({gamma}-FeOOH), 1 x 10{sup 9}{Omega} cm. The {rho} value of the Fe oxide-hydroxides, 1 x 10{sup 9}{Omega} cm, was found slightly higher than the {rho} value range of the formed oxide layer of the present study. This is because the former value was determined

  3. Differences between direct current and alternating current capacitance nonlinearities in high-k dielectrics and their relation to hopping conduction

    SciTech Connect

    Khaldi, O.; Kassmi, M.; Gonon, P. Vallée, C.; Mannequin, C.; Sylvestre, A.; Jomni, F.

    2014-08-28

    Capacitance nonlinearities were studied in atomic layer deposited HfO{sub 2} films using two types of signals: a pure ac voltage of large magnitude (ac nonlinearities) and a small ac voltage superimposed to a large dc voltage (dc nonlinearities). In theory, ac and dc nonlinearities should be of the same order of magnitude. However, in practice, ac nonlinearities are found to be an order of magnitude higher than dc nonlinearities. Besides capacitance nonlinearities, hopping conduction is studied using low-frequency impedance measurements and is discussed through the correlated barrier hopping model. The link between hopping and nonlinearity is established. The ac nonlinearities are ascribed to the polarization of isolated defect pairs, while dc nonlinearities are attributed to electrode polarization which originates from defect percolation paths. Both the ac and dc capacitance nonlinearities display an exponential variation with voltage, which results from field-induced lowering of the hopping barrier energy.

  4. Low-frequency ac electroporation shows strong frequency dependence and yields comparable transfection results to dc electroporation.

    PubMed

    Zhan, Yihong; Cao, Zhenning; Bao, Ning; Li, Jianbo; Wang, Jun; Geng, Tao; Lin, Hao; Lu, Chang

    2012-06-28

    Conventional electroporation has been conducted by employing short direct current (dc) pulses for delivery of macromolecules such as DNA into cells. The use of alternating current (ac) field for electroporation has mostly been explored in the frequency range of 10kHz-1MHz. Based on Schwan equation, it was thought that with low ac frequencies (10Hz-10kHz), the transmembrane potential does not vary with the frequency. In this report, we utilized a flow-through electroporation technique that employed continuous 10Hz-10kHz ac field (based on either sine waves or square waves) for electroporation of cells with defined duration and intensity. Our results reveal that electropermeabilization becomes weaker with increased frequency in this range. In contrast, transfection efficiency with DNA reaches its maximum at medium frequencies (100-1000Hz) in the range. We postulate that the relationship between the transfection efficiency and the ac frequency is determined by combined effects from electrophoretic movement of DNA in the ac field, dependence of the DNA/membrane interaction on the ac frequency, and variation of transfection under different electropermeabilization intensities. The fact that ac electroporation in this frequency range yields high efficiency for transfection (up to ~71% for Chinese hamster ovary cells) and permeabilization suggests its potential for gene delivery.

  5. Long-range response in ac electricity grids.

    PubMed

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013)EPJBFY1434-602810.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology-for example, caused by power outages or grid extensions-a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014)1951-635510.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found. PMID:27575148

  6. Long-range response in ac electricity grids

    NASA Astrophysics Data System (ADS)

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013), 10.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology—for example, caused by power outages or grid extensions—a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014), 10.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found.

  7. Long-range response in ac electricity grids.

    PubMed

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013)EPJBFY1434-602810.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology-for example, caused by power outages or grid extensions-a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014)1951-635510.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found.

  8. High voltage AC/AC electrochemical capacitor operating at low temperature in salt aqueous electrolyte

    NASA Astrophysics Data System (ADS)

    Abbas, Qamar; Béguin, François

    2016-06-01

    We demonstrate that an activated carbon (AC)-based electrochemical capacitor implementing aqueous lithium sulfate electrolyte in 7:3 vol:vol water/methanol mixture can operate down to -40 °C with good electrochemical performance. Three-electrode cell investigations show that the faradaic contributions related with hydrogen chemisorption in the negative AC electrode are thermodynamically unfavored at -40 °C, enabling the system to work as a typical electrical double-layer (EDL) capacitor. After prolonged floating of the AC/AC capacitor at 1.6 V and -40°C, the capacitance, equivalent series resistance and efficiency remain constant, demonstrating the absence of ageing related with side redox reactions at this temperature. Interestingly, when temperature is increased back to 24 °C, the redox behavior due to hydrogen storage reappears and the system behaves as a freshly prepared one.

  9. Microwave conductance of ferroelectric domain walls in lead titanate

    NASA Astrophysics Data System (ADS)

    Tselev, Alexander; Cao, Ye; Yu, Pu; Kalinin, Sergei V.; Maksymovych, Petro

    Numerous theoretical works predicted electronically conducting domain walls in otherwise insulating ferroelectric crystals. A number of recent experiments reported conducting walls, although conductivity itself and a conclusive proof of conductance mechanism remain elusive, largely due to the electrical contact problem. The latter can be overcome using high-frequency AC voltage. Here we will present our successful measurements of microwave conductance at 180o domain walls in lead titanate using microwave microscopy. AC conducting domain walls can be repeatably reconfigured and have extraordinary stability in time and temperature. AC conductivity is detected even when DC is not. Quantitative modeling reveals that the conductance of domain walls is comparable to doped silicon. We will also present a new and robust mechanism to create charged domain walls in any ferroelectric lattice. Overall, this sets the stage for a new generation of local experiments on conducting domain walls, and furthers the prospects of their application in fast electronic devices. AT, YC, SVK, PM supported by Division of Materials Sciences and Engineering, Office of Science, Basic Energy Sciences, U. S. DOE. PY supported by the National Basic Research Program of China (2015CB921700).

  10. What's Up in the Air?

    ERIC Educational Resources Information Center

    Lowe, Elizabeth M.

    1981-01-01

    Reviews progress made in the past decade to reduce levels of air pollutants in New York. Described are current monitoring and control efforts conducted by the New York State Department of Environmental Conservation. (WB)

  11. Long-term performance of passive materials for removal of ozone from indoor air.

    PubMed

    Cros, C J; Morrison, G C; Siegel, J A; Corsi, R L

    2012-02-01

    The health effects associated with exposure to ozone range from respiratory irritation to increased mortality. In this paper, we explore the use of three green building materials and an activated carbon (AC) mat that remove ozone from indoor air. We studied the effects of long-term exposure of these materials to real environments on ozone removal capability and pre- and post-ozonation emissions. A field study was completed over a 6-month period, and laboratory testing was intermittently conducted on material samples retrieved from the field. The results show sustained ozone removal for all materials except recycled carpet, with greatest ozone deposition velocity for AC mat (2.5-3.8 m/h) and perlite-based ceiling tile (2.2-3.2 m/h). Carbonyl emission rates were low for AC across all field sites. Painted gypsum wallboard and perlite-based ceiling tile had similar overall emission rates over the 6-month period, while carpet had large initial emission rates of undesirable by-products that decayed rapidly but remained high compared with other materials. This study confirms that AC mats and perlite-based ceiling tile are viable surfaces for inclusion in buildings to remove ozone without generating undesirable by-products. PRACTICAL IMPLICATIONS The use of passive removal materials for ozone control could decrease the need for, or even render unnecessary, active but energy consuming control solutions. In buildings where ozone should be controlled (high outdoor ozone concentrations, sensitive populations), materials specifically designed or selected for removing ozone could be implemented, as long as ozone removal is not associated with large emissions of harmful by-products. We find that activated carbon mats and perlite-based ceiling tiles can provide substantial, long-lasting, ozone control.

  12. 48 CFR Appendixes A-C to Chapter 7 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false A Appendixes A-C to Chapter 7 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT Appendixes A-C to Chapter 7...

  13. 48 CFR Appendixes A-C to Chapter 7 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false A Appendixes A-C to Chapter 7 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT Appendixes A-C to Chapter 7...

  14. 21 CFR 886.1630 - AC-powered photostimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Identification. An AC-powered photostimulator is an AC-powered device intended to provide light stimulus which allows measurement of retinal or visual function by perceptual or electrical methods (e.g.,...

  15. Numerical study of dc-biased ac-electrokinetic flow over symmetrical electrodes.

    PubMed

    Yang Ng, Wee; Ramos, Antonio; Cheong Lam, Yee; Rodriguez, Isabel

    2012-03-01

    This paper presents a numerical study of DC-biased AC-electrokinetic (DC-biased ACEK) flow over a pair of symmetrical electrodes. The flow mechanism is based on a transverse conductivity gradient created through incipient Faradaic reactions occurring at the electrodes when a DC-bias is applied. The DC biased AC electric field acting on this gradient generates a fluid flow in the form of vortexes. To understand more in depth the DC-biased ACEK flow mechanism, a phenomenological model is developed to study the effects of voltage, conductivity ratio, channel width, depth, and aspect ratio on the induced flow characteristics. It was found that flow velocity on the order of mm/s can be produced at higher voltage and conductivity ratio. Such rapid flow velocity is one of the highest reported in microsystems technology using electrokinetics. PMID:22662084

  16. Numerical study of dc-biased ac-electrokinetic flow over symmetrical electrodes

    PubMed Central

    Yang Ng, Wee; Ramos, Antonio; Cheong Lam, Yee; Rodriguez, Isabel

    2012-01-01

    This paper presents a numerical study of DC-biased AC-electrokinetic (DC-biased ACEK) flow over a pair of symmetrical electrodes. The flow mechanism is based on a transverse conductivity gradient created through incipient Faradaic reactions occurring at the electrodes when a DC-bias is applied. The DC biased AC electric field acting on this gradient generates a fluid flow in the form of vortexes. To understand more in depth the DC-biased ACEK flow mechanism, a phenomenological model is developed to study the effects of voltage, conductivity ratio, channel width, depth, and aspect ratio on the induced flow characteristics. It was found that flow velocity on the order of mm/s can be produced at higher voltage and conductivity ratio. Such rapid flow velocity is one of the highest reported in microsystems technology using electrokinetics. PMID:22662084

  17. AC Electric Field Activated Shape Memory Polymer Composite

    NASA Technical Reports Server (NTRS)

    Kang, Jin Ho; Siochi, Emilie J.; Penner, Ronald K.; Turner, Travis L.

    2011-01-01

    Shape memory materials have drawn interest for applications like intelligent medical devices, deployable space structures and morphing structures. Compared to other shape memory materials like shape memory alloys (SMAs) or shape memory ceramics (SMCs), shape memory polymers (SMPs) have high elastic deformation that is amenable to tailored of mechanical properties, have lower density, and are easily processed. However, SMPs have low recovery stress and long response times. A new shape memory thermosetting polymer nanocomposite (LaRC-SMPC) was synthesized with conductive fillers to enhance its thermo-mechanical characteristics. A new composition of shape memory thermosetting polymer nanocomposite (LaRC-SMPC) was synthesized with conductive functionalized graphene sheets (FGS) to enhance its thermo-mechanical characteristics. The elastic modulus of LaRC-SMPC is approximately 2.7 GPa at room temperature and 4.3 MPa above its glass transition temperature. Conductive FGSs-doped LaRC-SMPC exhibited higher conductivity compared to pristine LaRC SMP. Applying an electric field at between 0.1 Hz and 1 kHz induced faster heating to activate the LaRC-SMPC s shape memory effect relative to applying DC electric field or AC electric field at frequencies exceeding1 kHz.

  18. The effect of heat treatment and test parameters on the aqueous stress corrosion cracking of D6AC steel

    NASA Technical Reports Server (NTRS)

    Gilbreath, W. P.; Adamson, M. J.

    1974-01-01

    The crack growth behavior of D6AC steel as a function of stress intensity, stress and corrosion history and test technique, under sustained load in natural seawater, 3.3 percent NaCl solution, distilled water, and high humidity air was investigated. Reported investigations of D6AC were considered with emphasis on thermal treatment, specimen configuration, fracture toughness, crack-growth rates, initiation period, threshold, and the extension of corrosion fatigue data to sustained load conditions. Stress history effects were found to be most important in that they controlled incubation period, initial crack growth rates, and apparent threshold.

  19. Air Pollution.

    ERIC Educational Resources Information Center

    Fox, Donald L.

    1989-01-01

    Materials related to air pollution are reviewed for the period January 1987, to October 1988. The topics are pollution monitoring, air pollution, and environmental chemistry. The organization consists of two major analytical divisions: (1) gaseous methods; and (2) aerosol and particulate methods. (MVL)

  20. Air Pollution.

    EPA Science Inventory

    Air quality is affected by many types of pollutants that are emitted from various sources, including stationary and mobile. These sources release both criteria and hazardous air pollutants, which cause health effects, ecological harm, and material damage. They are generally categ...

  1. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered patient lift. 880.5500 Section 880.5500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an...

  2. Methods for Addressing Missing Data with Applications from ACS Exams

    ERIC Educational Resources Information Center

    Brandriet, Alexandra; Holme, Thomas

    2015-01-01

    As part of the ACS Examinations Institute (ACS-EI) national norming process, student performance data sets are collected from professors at colleges and universities from around the United States. Because the data sets are collected on a volunteer basis, the ACS-EI often receives data sets with only students' total scores and without the students'…

  3. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  4. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  5. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  6. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  7. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Area Coverage Survey (ACS). 1737.31 Section 1737.31... Studies-Area Coverage Survey and Loan Design § 1737.31 Area Coverage Survey (ACS). (a) The Area Coverage Survey (ACS) is a market forecast of service requirements of subscribers in a proposed service area....

  8. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Area Coverage Survey (ACS). 1737.31 Section 1737.31... Studies-Area Coverage Survey and Loan Design § 1737.31 Area Coverage Survey (ACS). (a) The Area Coverage Survey (ACS) is a market forecast of service requirements of subscribers in a proposed service area....

  9. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Area Coverage Survey (ACS). 1737.31 Section 1737.31... Studies-Area Coverage Survey and Loan Design § 1737.31 Area Coverage Survey (ACS). (a) The Area Coverage Survey (ACS) is a market forecast of service requirements of subscribers in a proposed service area....

  10. 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

  11. Increased long-flight activity triggered in beet armyworm by larval feeding on diet containing Cry1Ac protoxin.

    PubMed

    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

  12. Effect of low voltage AC fields on cardiovascular implants.

    PubMed

    Kothandaraman, Anjana; Anson, Tony; Reynolds, Alan

    2015-01-01

    Coronary Artery Stents have been the preferred form of treatment for vascular occlusive disease, due to the minimally invasive surgical procedure, post-operative recovery time and cost, when compared to open coronary bypass surgery. The cellular response upon applying an AC electric field to type 316LM Stainless Steel stent mimics was investigated in this paper. The highest RBC adhesion was observed at voltages higher than 88 mV and lower than 74 mV. Their unique alignment along the lines of fracture on the stent surface at 88 mV was a phenomenon caused by an increase in electrical conductivity in these regions. Being able to control RBC adhesion may have various clinical implications such as inhibition of thrombus formation, and provide a basis to analyse whether electric fields may be applied to cancer therapy as well.

  13. An AC drive system for a battery driven moped

    SciTech Connect

    Nandi, S.; Saha, S.; Sharon, M.; Sundersingh, V.P.

    1995-12-31

    A petrol driven moped is converted to an electric one by replacing the petrol engine by a three phase 1.5 HR, AC squirrel cage induction motor drive system. The motor voltage rating selected is 200 V to keep the DC boost voltage level to a reasonable value.f the power source used is a high energy density, 24 V, 110 Ah, Ni-Zn battery. A modified indirect current controlled step-up chopper as well as a standard push-pull DC-DC boost converter is studied for the boost scheme. A simple three phase quasi-square wave inverter is designed along with suitable protection for driving the motor. Successful trial test of the system has been conducted at the laboratory.

  14. Mortality and long-term exposure to ambient air pollution: ongoing analyses based on the American Cancer Society cohort.

    PubMed

    Krewski, Daniel; Burnett, Richard; Jerrett, Michael; Pope, C Arden; Rainham, Daniel; Calle, Eugenia; Thurston, George; Thun, Michael

    This article provides an overview of previous analysis and reanalysis of the American Cancer Society (ACS) cohort, along with an indication of current ongoing analyses of the cohort with additional follow-up information through to 2000. Results of the first analysis conducted by Pope et al. (1995) showed that higher average sulfate levels were associated with increased mortality, particularly from cardiopulmonary disease. A reanalysis of the ACS cohort, undertaken by Krewski et al. (2000), found the original risk estimates for fine-particle and sulfate air pollution to be highly robust against alternative statistical techniques and spatial modeling approaches. A detailed investigation of covariate effects found a significant modifying effect of education with risk of mortality associated with fine particles declining with increasing educational attainment. Pope et al. (2002) subsequently reported results of a subsequent study using an additional 10 yr of follow-up of the ACS cohort. This updated analysis included gaseous copollutant and new fine-particle measurements, more comprehensive information on occupational exposures, dietary variables, and the most recent developments in statistical modeling integrating random effects and nonparametric spatial smoothing into the Cox proportional hazards model. Robust associations between ambient fine particulate air pollution and elevated risks of cardiopulmonary and lung cancer mortality were clearly evident, providing the strongest evidence to date that long-term exposure to fine particles is an important health risk. Current ongoing analysis using the extended follow-up information will explore the role of ecologic, economic, and, demographic covariates in the particulate air pollution and mortality association. This analysis will also provide insight into the role of spatial autocorrelation at multiple geographic scales, and whether critical instances in time of exposure to fine particles influence the risk of mortality

  15. Micro pumping methods based on AC electrokinetics and Electrorheologically actuated PDMS valves

    NASA Astrophysics Data System (ADS)

    Soni, Gaurav; Squires, Todd; Meinhart, Carl

    2006-11-01

    We have developed 2 different micropumping methods for transporting ionic fluids through microchannels. The first method is based on Induced Charge Electroosmosis (ICEO) and AC flow field-effect. We used an AC electric field to produce a symmetric ICEO flow on a planar electrode, called `gate'. In order to break the symmetry of ICEO, we applied an additional AC voltage to the gate electrode. Such modulation of the gate potential is called field effect and produces a unidirectional pumping over the gate surface. We used micro PIV to measure pumping velocities for a range of ionic concentration, AC frequency and gate voltage. We have also conducted numerical simulations to understand the deteriorating effect of lateral conduction of surface charge on the pumping velocities. The second method is based on vibration of a flexible PDMS diaphragm actuated by an electrorheological (ER) fluid. ER fluid is a colloidal suspension exhibiting a reversible liquid-to-solid transition under an electric field. This liquid-to-solid transition can yield very high shear stress and can be used to open and close a PDMS valve. Three such valves were fabricated and actuated in a peristaltic fashion in order to achieve positive displacement pumping of fluids.

  16. Kubo conductivity tensor for two- and three-dimensional magnetic nulls.

    PubMed

    St-Onge, D A; Sydora, R D

    2014-09-01

    The complete Kubo conductivity tensor is computed in two- and three-dimensional linear magnetic null systems using collisionless single-particle simulations. Regions of chaotic charged-particle dynamics are constructed for each case. It is found that stochastic frequency mixing of particle bounce motion, as well as gyromotion, contribute significantly to the conductivity. The conductivity curves are well approximated by power laws over a certain frequency range and the ac conductivity is found to be an order of magnitude smaller than the dc value, leading to enhanced resistivity, particularly near the cyclotron frequency. The ac conductivities must be accounted for in computation of the total dissipation. PMID:25314543

  17. A HTS scanning magnet and AC operation

    NASA Astrophysics Data System (ADS)

    Hatanaka, K.; Nakagawa, J.; Fukuda, M.; Yorita, T.; Saito, T.; Sakemi, Y.; Kawaguchi, T.; Noda, K.

    2010-04-01

    A scanning magnet using high-temperature superconductor (HTS) wire was designed, built, and tested for its suitability as a beam scanner. After successful cooling tests, the magnet performance was studied using DC and AC currents. With DC current the magnet was successfully operated to generate designed field distributions and effective length. In AC mode, the magnet was operated at frequencies of 30-59 Hz and a temperature of 77 K as well as 10-20 Hz and 20 K. The power losses dissipated in the coils were measured and compared with the model calculations. The observed losses per cycle were independent of the frequency and the scaling law of the transport current was consistent with theoretical predictions for hysteretic losses in HTS wires.

  18. 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.

  19. Graphs for Isotopes of 89-Ac (Actinium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 89-Ac (Actinium, atomic number Z = 89).

  20. Large aperture ac interferometer for optical testing.

    PubMed

    Moore, D T; Murray, R; Neves, F B

    1978-12-15

    A 20-cm clear aperture modified Twyman-Green interferometer is described. The system measures phase with an AC technique called phase-lock interferometry while scanning the aperture with a dual galvanometer scanning system. Position information and phase are stored in a minicomputer with disk storage. This information is manipulated with associated software, and the wavefront deformation due to a test component is graphically displayed in perspective and contour on a CRT terminal. PMID:20208642

  1. Highlights of the Dallas ACS Meeting

    NASA Astrophysics Data System (ADS)

    Wildeman, Thomas R.; Freilich, Mark; Kelter, Paul B.

    1998-06-01

    Without a doubt, a primary feature of the 1998 Spring National Meeting in Dallas was the High School Program, which was organized by George Hague, and the impact that the Texas teachers had on other participants. Over 150 teachers registered for the meeting and participated in the program. Their organizational skills were used to reinstitute the High School/College Interface Luncheon. (The High School/College Interface Luncheon will also be held at the Fall ACS Meeting in Boston.)

  2. 78 FR 49318 - Availability of Draft Advisory Circular (AC) 90-106A and AC 20-167A

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-13

    ... Systems (78 FR 34935-34958) (Docket No.: FAA-2013-0485; Notice No. 1209). AC 90-106A, Enhanced Flight... the Federal Register published on April 11, 2000 (65 FR 19477-19478), as well as at http://DocketsInfo... Federal Aviation Administration Availability of Draft Advisory Circular (AC) 90-106A and AC 20-...

  3. Using Field-Metered Data to Quantify Annual Energy Use of Portable Air Conditioners

    SciTech Connect

    Burke, Thomas; Willem, Henry; Ni, Chun Chun; Stratton, Hannah; Chen, Yuting; Ganeshalingam, Mohan; Iyer, Maithili; Price, Sarah; Dunham, Camilla

    2014-12-01

    As many regions of the United States experience rising temperatures, consumers have come to rely increasingly on cooling appliances (including portable air conditioners) to provide a comfortable indoor temperature. Home occupants sometimes use a portable air conditioner (PAC) to maintain a desired indoor temperature in a single room or enclosed space. Although PACs in residential use are few compared to centrally installed and room air conditioning (AC) units, the past few years have witnessed an increase of PACs use throughout the United States. There is, however, little information and few research projects focused on the energy consumption and performance of PACs, particularly studies that collect information from field applications of PACs. The operation and energy consumption of PACs may differ among geographic locations and households, because of variations in cooling load, frequency, duration of use, and other user-selected settings. In addition, the performance of building envelope (thermal mass and air leakage) as well as inter-zonal mixing within the building would substantially influence the ability to control and maintain desirable indoor thermal conditions. Lawrence Berkeley National Laboratory (LBNL) conducted an initial field-metering study aimed at increasing the knowledge and data related to PAC operation and energy consumption in the United States.

  4. Level structure and reflection asymmetric shape in sup 223 Ac

    SciTech Connect

    Sheline, R.K.; Liang, C.F.; Paris, P. )

    1990-07-20

    Mass separated sources of {sup 227}Pa (separated as PaF{sub 4}{sup +} ions) were used to study the level structure of {sup 223}Ac following alpha decay. The levels in {sup 223}Ac are interpreted as K = 5/2{sup {plus minus}} parity doublet bands which occur naturally in reflection asymmetric models and the multiphonon octupole model. The anomalous structure of the K = 3/2{sup {minus}} band is explained in terms of Coriolis coupling. The low lying parity doublet bands in {sup 223}Ac, {sup 225}Ac, and {sup 227}Ac are compared and contrasted.

  5. Rapid evolution of air sensor technologies

    EPA Science Inventory

    Outdoor air pollution measurement approaches have historically been conducted using stationary shelters that require significant space, power, and expertise to operate. The cost and logistical requirements to conduct monitoring have limited the number of locations with continuou...

  6. 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.

  7. Phase Stability and Electrical Conductivity of Ca-doped LaNb1-xTaxO4- high temperature proton conductors

    SciTech Connect

    Bi, Zhonghe; Kim, Jung-Hyun; Bridges, Craig A; Huq, Ashfia; Paranthaman, Mariappan Parans

    2011-01-01

    The electrical conductivity, phase structure and stability of La0.99Ca0.01Nb1-xTaxO4- (x=0, 0.1, 0.2, 0.3, 0.4 and 0.5, =0.005) a potential candidate for proton conductor for Solid Oxide Fuel Cells (SOFCs) have been investigated using AC impedance technique and in-situ X-ray powder diffraction. Partially substituting Nb with Ta elevates the phase transition temperature (from monoclinic to a tetragonal structure at high temperature) from ~520 C for x=0 to near 800 C for x=0.4. AC conductivity of the La0.99Ca0.01Nb1-xTaxO4- both in dry and wet air decreased slightly with increase of Ta content above 750 C, while below 500 C, it decreased one order of magnitude. It was also found that the activation energy for the total conductivity increases with increasing Ta content from 0.50 eV (x=0) to 0.58 eV (x=0.3) for the tetragonal phase, however, it decreases with increasing Ta content from 1.18 eV (x=0) to 1.08 eV (x=0.4) for the monoclinic phase. By removing the detrimental high temperature phase transition out of intermediate temperature range, partial substitution of Nb with Ta brings this class of material closer to its application in intermediate-temperature SOFCs.

  8. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Characteristics of alternating current hopping conductivity in DNA sequences

    NASA Astrophysics Data System (ADS)

    Ma, Song-Shan; Xu, Hui; Wang, Huan-You; Guo, Rui

    2009-08-01

    This paper presents a model to describe alternating current (AC) conductivity of DNA sequences, in which DNA is considered as a one-dimensional (1D) disordered system, and electrons transport via hopping between localized states. It finds that AC conductivity in DNA sequences increases as the frequency of the external electric field rises, and it takes the form of øac(ω) ~ ω2 ln2(1/ω). Also AC conductivity of DNA sequences increases with the increase of temperature, this phenomenon presents characteristics of weak temperature-dependence. Meanwhile, the AC conductivity in an off-diagonally correlated case is much larger than that in the uncorrelated case of the Anderson limit in low temperatures, which indicates that the off-diagonal correlations in DNA sequences have a great effect on the AC conductivity, while at high temperature the off-diagonal correlations no longer play a vital role in electric transport. In addition, the proportion of nucleotide pairs p also plays an important role in AC electron transport of DNA sequences. For p < 0.5, the conductivity of DNA sequence decreases with the increase of p, while for p >= 0.5, the conductivity increases with the increase of p.

  9. Development of a hardware-based AC microgrid for AC stability assessment

    NASA Astrophysics Data System (ADS)

    Swanson, Robert R.

    As more power electronic-based devices enable the development of high-bandwidth AC microgrids, the topic of microgrid power distribution stability has become of increased interest. Recently, researchers have proposed a relatively straightforward method to assess the stability of AC systems based upon the time-constants of sources, the net bus capacitance, and the rate limits of sources. In this research, a focus has been to develop a hardware test system to evaluate AC system stability. As a first step, a time domain model of a two converter microgrid was established in which a three phase inverter acts as a power source and an active rectifier serves as an adjustable constant power AC load. The constant power load can be utilized to create rapid power flow transients to the generating system. As a second step, the inverter and active rectifier were designed using a Smart Power Module IGBT for switching and an embedded microcontroller as a processor for algorithm implementation. The inverter and active rectifier were designed to operate simultaneously using a synchronization signal to ensure each respective local controller operates in a common reference frame. Finally, the physical system was created and initial testing performed to validate the hardware functionality as a variable amplitude and variable frequency AC system.

  10. Characterization and photocatalytic activity of Zn 2+-TiO 2/AC composite photocatalyst

    NASA Astrophysics Data System (ADS)

    Lu, Xincheng; Jiang, Jianchun; Sun, Kang; Cui, Dandan

    2011-12-01

    Activated carbon (AC) supported Zn 2+-TiO 2 photocatalyst was prepared by sol-gel method. The prepared samples were characterized by X-ray diffraction, scanning electron micrograph, nitrogen absorption, diffuse reflectance UV/VIS and X-ray photoelectron spectroscopy. Using toluene as a pollution target, the photocatalytic activity of photocatalyst was evaluated. The results showed that prepared photocatalyst was obviously helpful for the removal of toluene in air. The photocatalytic degradation of toluene by Zn 2+-TiO 2/AC reached 100% for 40 min and remained 75% after 160 min, while degradation by TiO 2 was only 30%. It indicated that the photocatalytic activity of prepared photocatalyst was enhanced. It is due to Zn 2+-doping increased the oxidation and reduction of hole-electron pairs, which was the important factor in heterogeneous photocatalysis.

  11. Molecular biology of maize Ac/Ds elements: an overview.

    PubMed

    Lazarow, Katina; Doll, My-Linh; Kunze, Reinhard

    2013-01-01

    Maize Activator (Ac) is one of the prototype transposable elements of the hAT transposon superfamily, members of which were identified in plants, fungi, and animals. The autonomous Ac and nonautonomous Dissociation (Ds) elements are mobilized by the single transposase protein encoded by Ac. To date Ac/Ds transposons were shown to be functional in approximately 20 plant species and have become the most widely used transposable elements for gene tagging and functional genomics approaches in plants. In this chapter we review the biology, regulation, and transposition mechanism of Ac/Ds elements in maize and heterologous plants. We discuss the parameters that are known to influence the functionality and transposition efficiency of Ac/Ds transposons and need to be considered when designing Ac transposase expression constructs and Ds elements for application in heterologous plant species.

  12. Air Pollution

    MedlinePlus

    ... tobacco smoke. How is air pollution linked to climate change? While climate change is a global process, it ... ozone levels are also a concern. Impacts of Climate Change on Human Health in the United States: A ...

  13. Air Apparent.

    ERIC Educational Resources Information Center

    Harbster, David A.

    1988-01-01

    Explains the principle upon which a barometer operates. Describes how to construct two barometric devices for use in the classroom that show air's changing pressure. Cites some conditions for predicting weather. (RT)

  14. Urban air

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Air pollution and the risk of potential health effects are not sufficiently convincing reasons for people to stop driving their cars, according to a study by the Population Reference Bureau (PRB) released on November 18.While sufficient levels of suspended particulate matter, carbon monoxide, and lead can present health concerns, the study found that many people surveyed for the study were not convinced of the clear linkage between air pollution and health.

  15. The Crisis in Air Pollution Manpower Development

    ERIC Educational Resources Information Center

    Moeller, Dade W.

    1974-01-01

    Three studies conducted by the National Air Pollution Manpower Development Advisory Committee concluded there is a crisis in air pollution manpower development within the United States today. The studies investigated the existing federal manpower program, air pollution educational requirements and the quality of graduate level university programs.…

  16. Thermal conductivity of cane fiberboard

    SciTech Connect

    Leader, D.R.

    1995-05-01

    The thermal conductivity of cane fiberboard was measured in two planes; parallel to the surface and perpendicular to the surface of the manufactured sheet. The information was necessary to better understand the thermal response of a loaded shipping container. The tests demonstrated that the thermal conductivity of cane fiberboard in the plane parallel to the surface of the sheet was nearly twice as great as the conductivity of the same material in a plane perpendicular to the sheet. There was no significant difference in the conductivity in different directions within the plane parallel to the surface, and the presence of glue between layers of fiberboard did not significantly change the conductivity of the assembly. The tests revealed that the thermal conductivity measured in a direction perpendicular to the plane of the surface of a stack of cane fiberboard sheets not bonded together, decreases with an increase in the mean temperature. This was determined to be the result of air gaps between the sheets of fiberboard, and not related to the properties of the material itself

  17. An automatic AC/DC thermal voltage converter and AC voltage calibration system

    NASA Astrophysics Data System (ADS)

    Lentner, K. J.; Flach, D. R.; Bell, B. A.

    1985-10-01

    An automatic ac/dc difference calibration system is described which uses direct measurement of thermoelement emfs. In addition to ac/dc difference testing, the system can be used to measure some important characteristics of thermoelements, as well as to calibrate ac voltage calibrators and precision voltmeters. The system operates over a frquency range from 20 Hz to 100 kHz, covering the voltage range from 0.5 V to 1 kv. For all voltages the total measurement uncertainties expected (including the uncertainty of the specific reference thermal converters used) were 50 parts per million (ppm) at frequencies from 20 Hz to 20 kHz, inclusive, and 100 ppm at higher frequencies up to 100 kHz.

  18. Automatic ac/dc thermal voltage converter and ac voltage calibration system

    NASA Astrophysics Data System (ADS)

    Lentner, K. J.; Flach, D. R.; Bell, B. A.

    1984-11-01

    An automatic ac/dc difference calibration system is described which uses direct measurement of thermoelement emfs. In addition to ac/dc difference testing, the system can be used to measure some important characteristics of thermoelements, as well as to calibrate ac voltage calibrators and precision voltmeters. The system operates over a frequency range from 20 Hz to 100 kHz, covering the voltage range from 0.5 V to 1 kv. For all voltages the total measurement uncertainties expected (including the uncertainty of the specific reference thermal converters used) were 50 parts per million (ppm) at frequencies from 20 Hz to 20 kHz, inclusive, and 100 ppm at higher frequencies up to 100 kHz.

  19. 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.

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

    PubMed

    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(109KO)). Fluorescence and light microscopy showed that transfection of vAc(109KO) results in a single-cell infection phenotype. Viral DNA replication is unaffected and the development of occlusion bodies in vAc(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(50) showed that vAc(109KO) produced BV but the virions are non-infectious. The vAc(109KO) BV were indistinguishable from the BV of repaired and wild type control viruses as determined by negative staining and electron microscopy.

  1. Evaluation of workplace air monitoring locations

    SciTech Connect

    Stoetzel, G.A.; Cicotte, G.R.; Lynch, T.P. ); Aldrich, L.K. )

    1991-10-01

    Current federal guidance on occupational radiation protection recognizes the importance of conducting air flow studies to assist in the placement of air sampling and monitoring equipment. In support of this, Pacific Northwest Laboratory has provided technical assistance to Westinghouse Hanford Company for the purpose of evaluating the adequacy of air sampling and monitoring locations at selected Hanford facilities. Qualitative air flow studies were performed using smoke aerosols to visually determine air movement. Three examples are provided of how air flow studies results, along with information on the purpose of the air sample being collected, were used as a guide in placing the air samplers and monitors. Preparatory steps in conducting an air flow study should include: (1) identifying type of work performed in the work area including any actual or potential release points; (2) determining the amounts of radioactive material available for release and its chemical and physical form; (3) obtaining accurate work area descriptions and diagrams; (4) identifying the location of existing air samplers and monitors; (5) documenting physical and ventilation configurations; (6) notifying appropriate staff of the test; and (7) obtaining necessary equipment and supplies. The primary steps in conducting an air flow study are measurements of air velocities in the work area, release of the smoke aerosol at selected locations in the work area and the observation of air flow patterns, and finally evaluation and documentation of the results. 2 refs., 3 figs.

  2. Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz tone pips

    PubMed Central

    Todd, N.P.M.; Paillard, A.C.; Kluk, K.; Whittle, E.; Colebatch, J.G.

    2014-01-01

    Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulation and by conducting a source analysis of the resulting evoked potentials of short and long latency. Ten healthy, right-handed subjects were recruited and evoked potentials were recorded to both left- and right-ear sound stimulation, above and below vestibular threshold. Below VEMP threshold, typical AEPs were recorded, consisting of mid-latency (MLR) waves Na and Pa followed by long latency AEPs (LAEPs) N1 and P2. In the supra-threshold condition, the expected changes in morphology were observed, consisting of: (1) short-latency vestibular evoked potentials (VsEPs) which have no auditory correlate, i.e. the ocular VEMP (OVEMP) and inion response related potentials; (2) a later deflection, labelled N42/P52, followed by the LAEPs N1 and P2. Statistical analysis of the vestibular dependent responses indicated a contralateral effect for inion related short-latency responses and a left-ear/right-hemisphere advantage for the long-latency responses. Source analysis indicated that the short-latency effects may be mediated by a contralateral projection to left cerebellum, while the long-latency effects were mediated by a contralateral projection to right cingulate cortex. In addition we found evidence of a possible vestibular contribution to the auditory T-complex in radial temporal lobe sources. These last results raise the possibility that acoustic activation of the otolith organs could potentially contribute to auditory processing. PMID:24699384

  3. Method and apparatus for generating radiation utilizing DC to AC conversion with a conductive front

    DOEpatents

    Dawson, J.M.; Mori, W.B.; Lai, C.H.; Katsouleas, T.C.

    1998-07-14

    Method and apparatus ar disclosed for generating radiation of high power, variable duration and broad tunability over several orders of magnitude from a laser-ionized gas-filled capacitor array. The method and apparatus convert a DC electric field pattern into a coherent electromagnetic wave train when a relativistic ionization front passes between the capacitor plates. The frequency and duration of the radiation is controlled by the gas pressure and capacitor spacing. 4 figs.

  4. Method and apparatus for generating radiation utilizing DC to AC conversion with a conductive front

    DOEpatents

    Dawson, John M.; Mori, Warren B.; Lai, Chih-Hsiang; Katsouleas, Thomas C.

    1998-01-01

    Method and apparatus for generating radiation of high power, variable duration and broad tunability over several orders of magnitude from a laser-ionized gas-filled capacitor array. The method and apparatus convert a DC electric field pattern into a coherent electromagnetic wave train when a relativistic ionization front passes between the capacitor plates. The frequency and duration of the radiation is controlled by the gas pressure and capacitor spacing.

  5. 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

  6. Deployable Engine Air Brake

    NASA Technical Reports Server (NTRS)

    2014-01-01

    On approach, next-generation aircraft are likely to have airframe noise levels that are comparable to or in excess of engine noise. ATA Engineering, Inc. (ATA) is developing a novel quiet engine air brake (EAB), a device that generates "equivalent drag" within the engine through stream thrust reduction by creating a swirling outflow in the turbofan exhaust nozzle. Two Phase II projects were conducted to mature this technology: (1) a concept development program (CDP) and (2) a system development program (SDP).

  7. Safeguarding indoor air quality

    SciTech Connect

    Sexton, K.; Wesolowski, J.J.

    1985-01-01

    California has created and implemented the first state program devoted exclusively to the investigation of nonindustrial indoor air quality. The program is responsible for promoting and conducting research on the determining factors of healthful indoor environments and is structured to obtain information about emission sources, ventilation effects, indoor concentrations, human activity patterns, exposures, health risks, control measures and public policy options. Data are gathered by a variety of methods, including research conducted by staff members, review of the available scientific literature, participation in technical meetings, contractual agreements with outside agencies, cooperative research projects with other groups and consultation with experts. 23 references, 1 figure, 1 table.

  8. 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. PMID:27558494

  9. A.C. Susceptometry Utilizing GMR sensors

    NASA Astrophysics Data System (ADS)

    Christy, Daniel; Shivaram, Bellave

    2001-11-01

    Superconducting quantum interference (SQUID) magnetometers remain as the most sensitive instruments to measure magnetic properties. However, the ready availability and rapid improvements in the sensitivity of magnetic field sensors based on giant magnetoresistance (GMR) effect combined with their low cost and ability to operate at room temperature opens up opportunities to exploit these new devices where the utmost sensitivity of SQUID based detection is not needed. In this article we present one such application of GMR sensors and demonstrate how they can enhance the signals obtained in a simple a.c. magnetic susceptibility apparatus.

  10. The attenuation of the levitation force of HTS bulk exposed to AC magnetic field on the above NdFeB guideway

    NASA Astrophysics Data System (ADS)

    Liu, Minxian; Wang, Yan

    2012-01-01

    In the present High Temperature Superconducting (HTS) maglev vehicle system, the air gaps between the adjacent permanent magnets make the magnetic fields above the NdFeB guideway non-uniform. So it is required to study the characteristics of levitation force of the HTS bulk affected by the non-uniform applied magnetic fields along the moving direction. In this paper, we have studied the characteristics of the levitation force relaxation by an experiment in which AC magnetic field generated by an electromagnet is used to simulate the time-varying magnetic field caused by the inhomogeneity of the NdFeB guideway. From the experiment results, it is found that the levitation force is attenuated with the application of the AC field, and the attenuation is increased with the amplitude of the AC field, but the attenuation is almost independent of the frequency the AC magnetic field.

  11. Evaluating sources of indoor air pollution

    SciTech Connect

    Tichenor, B.A.; Sparks, L.E.; White, J.B.; Jackson, M.D. )

    1988-01-01

    Scientists and engineers in the Indoor Air Brand of EPS'a Air and Energy Engineering Research Laboratory are conducting research to increase the state of knowledge concerning indoor air pollution factors. A three phase program is being implemented. The purpose of this paper is to show how their approach can be used to evaluate specific sources of indoor air pollution. Pollutants from two sources are examined: para-dichlorobenzene emissions from moth crystal cakes; and particulate emissions from unvented kerosene heaters.

  12. Sampling of power plant stacks for air toxic emissions: Topical report for Phases 1 and 2

    SciTech Connect

    1995-02-21

    Under contract with the US Department of Energy (DE-AC22-92PCO0367), Pittsburgh Energy Technology Center, Radian Corporation has conducted a test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPS). Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical charactization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on the relative toxicological effects of exposure to particulate emissions.

  13. 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.

  14. 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. PMID:24787317

  15. Retrofitting Air Conditioning and Duct Systems in Hot, Dry Climates

    SciTech Connect

    Shapiro, C.; Aldrich, R.; Arena, L.

    2012-07-01

    This technical report describes CARB's work with Clark County Community Resources Division in Las Vegas, Nevada, to optimize procedures for upgrading cooling systems on existing homes in the area to implement health, safety, and energy improvements. Detailed monitoring of five AC systems showed that three of the five systems met or exceeded air flow rate goals.

  16. Air surveillance

    SciTech Connect

    Patton, G.W.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the air surveillance and monitoring programs currently in operation at that Hanford Site. Atmospheric releases of pollutants from Hanford to the surrounding region are a potential source of human exposure. For that reason, both radioactive and nonradioactive materials in air are monitored at a number of locations. The influence of Hanford emissions on local radionuclide concentrations was evaluated by comparing concentrations measured at distant locations within the region to concentrations measured at the Site perimeter. This section discusses sample collection, analytical methods, and the results of the Hanford air surveillance program. A complete listing of all analytical results summarized in this section is reported separately by Bisping (1995).

  17. Fergusonite-type CeNbO{sub 4+δ}: Single crystal growth, symmetry revision and conductivity

    SciTech Connect

    Bayliss, Ryan D.; Pramana, Stevin S.; An, Tao; Wei, Fengxia; Kloc, Christian L.; White, Andrew J.P.; Skinner, Stephen J.; White, Timothy J.; Baikie, Tom

    2013-08-15

    Large fergusonite-type (ABO{sub 4}, A=Ce, B=Nb) oxide crystals, a prototype electrolyte composition for solid oxide fuel cells (SOFC), were prepared for the first time in a floating zone mirror furnace under air or argon atmospheres. While CeNbO{sub 4} grown in air contained CeNbO{sub 4.08} as a minor impurity that compromised structural analysis, the argon atmosphere yielded a single phase crystal of monoclinic CeNbO{sub 4}, as confirmed by selected area electron diffraction, powder and single crystal X-ray diffraction. The structure was determined in the standard space group setting C12/c1 (No. 15), rather than the commonly adopted I12/a1. AC impedance spectroscopy conducted under argon found that stoichiometric CeNbO{sub 4} single crystals showed lower conductivity compared to CeNbO{sub 4+δ} confirming interstitial oxygen can penetrate through fergusonite and is responsible for the higher conductivity associated with these oxides. - Graphical abstract: Large fergusonite-type CeNbO{sub 4} crystals were prepared for the first time in a floating zone mirror furnace. Crystal growth in an argon atmosphere yielded a single phase monoclinic CeNbO4, as confirmed by selected area electron diffraction, powder and single crystal X-ray diffraction. The structure was determined in the standard space group setting C12/c1 (No. 15), rather than the commonly adopted I12/a1. AC impedance spectroscopy found CeNbO{sub 4} single crystals showed lower conductivity compared to CeNbO{sub 4+δ} confirming interstitial oxygen can penetrate through fergusonite and is responsible for the higher conductivity associated with these oxides. Highlights: • Preparation of single crystals of CeNbO{sub 4} using a floating zone mirror furnace. • Correction to the crystal symmetry of the monoclinic form of CeNbO{sub 4}. • Report the conductivity of a single crystal of CeNbO{sub 4}.

  18. Thermal conductivity of carbonate rocks

    USGS Publications Warehouse

    Thomas, J.; Frost, R.R.; Harvey, R.D.

    1973-01-01

    The thermal conductivities of several well-defined carbonate rocks were determined near 40??C. Values range from 1.2 W m-1 C-1 for a highly porous chalk to 5.1 W m-1 C-1 for a dolomite. The thermal conductivity of magnesite (5.0) is at the high end of the range, and that for Iceland Spar Calcite (3.2) is near the middle. The values for limestones decrease linearly with increasing porosity. Dolomites of comparable porosity have greater thermal conductivities than limestones. Water-sorbed samples have expected greater thermal conductivities than air-saturated (dry) samples of the same rock. An anomalously large increase in the thermal conductivity of a water-sorbed clayey dolomite over that of the same sample when dry is attributed to the clay fraction, which swells during water inhibition, causing more solid-to-solid contacts within the dolomite framework. Measurements were made with a Colora Thermoconductometer. Chemical and mineralogical analyses were made and tabulated. Porosity of the rocks was determined by mercury porosimetry and also from density measurements. The Iceland Spar Calcite and magnesite were included for reference. ?? 1973.

  19. Air Cleaning Technologies

    PubMed Central

    2005-01-01

    water molecules and form cluster ions which are attracted to airborne particles. The cluster ion surrounds the airborne particle, and the positive and negative ions react to form hydroxyls. These hydroxyls steal the airborne particle’s hydrogen atom, which creates a hole in the particle’s outer protein membrane, thereby rendering it inactive. Because influenza is primarily acquired by large droplets and direct and indirect contact with an infectious person, any in-room air cleaner will have little benefit in controlling and preventing its spread. Therefore, there is no role for the Plasmacluster ion air purifier or any other in-room air cleaner in the control of the spread of influenza. Accordingly, for purposes of this review, the Medical Advisory Secretariat presents no further analysis of the Plasmacluster. Review Strategy The objective of the systematic review was to determine the effectiveness of in-room air cleaners with built in UVGI lights and HEPA filtration compared with those using HEPA filtration only. The Medical Advisory Secretariat searched the databases of MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, INAHATA (International Network of Agencies for Health Technology Assessment), Biosis Previews, Bacteriology Abstracts, Web of Science, Dissertation Abstracts, and NIOSHTIC 2. A meta-analysis was conducted if adequate data was available from 2 or more studies and where statistical and clinical heterogeneity among studies was not an issue. Otherwise, a qualitative review was completed. The GRADE system was used to summarize the quality of the body of evidence comprised of 1 or more studies. Summary of Findings There were no existing health technology assessments on air cleaning technology located during the literature review. The literature search yielded 59 citations of which none were retained. One study was retrieved from a reference list of a guidance document from the United States Centers for Disease Control and Prevention, which

  20. 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.

  1. 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.

  2. Resonant AC power system proof-of-concept test program

    NASA Astrophysics Data System (ADS)

    Wappes, Loran J.

    1986-10-01

    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.

  3. 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.

  4. Ac irreversibility line of bismuth-based high temperature superconductors

    SciTech Connect

    Mehdaoui, A.; Beille, J.; Berling, D.; Loegel, B.; Noudem, J.G.; Tournier, R.

    1997-09-01

    We discuss the magnetic properties of lead doped Bi-2223 bulk samples obtained through combined magnetic melt texturing and hot pressing (MMTHP). The ac complex susceptibility measurements are achieved over a broad ac field range (1 Oe{lt}h{sub ac}{lt}100 Oe) and show highly anisotropic properties. The intergranular coupling is improved in the direction perpendicular to the applied stress and magnetic field direction, and an intragranular loss peak is observed for the first time. A comparison is made with other bismuth-based compounds and it is shown that the MMTHP process shifts the ac irreversibility line (ac IL) toward higher fields. It is also shown that all the ac IL{close_quote}s for quasi 2D bismuth-based compounds show a nearly quadratic temperature dependence and deviate therefore strongly from the linear behavior observed in quasi 3D compounds and expected from a critical state model.{copyright} {ital 1997 Materials Research Society.}

  5. Intermolecular dearomative C2-arylation of N-Ac indoles activated by FeCl3.

    PubMed

    Nandi, Raj Kumar; Ratsch, Friederike; Beaud, Rodolphe; Guillot, Régis; Kouklovsky, Cyrille; Vincent, Guillaume

    2016-04-18

    We report the FeCl3-mediated direct addition of electron-rich arenes to the C2-position of electrophilic N-Ac indoles under mild conditions (room temperature, air). No functional group is required on the arene nucleophile: one of its C-H bonds is added to the C2[double bond, length as m-dash]C3 double bond of the indole nucleus in a Friedel-Crafts-type reaction. This dearomatisation process delivered a broad range of C2-arylated indolines. PMID:27005518

  6. A hybrid air conditioner driven by a hybrid solar collector

    NASA Astrophysics Data System (ADS)

    Al-Alili, Ali

    The objective of this thesis is to search for an efficient way of utilizing solar energy in air conditioning applications. The current solar Air Conditioners (A/C)s suffer from low Coefficient of Performance (COP) and performance degradation in hot and humid climates. By investigating the possible ways of utilizing solar energy in air conditioning applications, the bottlenecks in these approaches were identified. That resulted in proposing a novel system whose subsystem synergy led to a COP higher than unity. The proposed system was found to maintain indoor comfort at a higher COP compared to the most common solar A/Cs, especially under very hot and humid climate conditions. The novelty of the proposed A/C is to use a concentrating photovoltaic/thermal collector, which outputs thermal and electrical energy simultaneously, to drive a hybrid A/C. The performance of the hybrid A/C, which consists of a desiccant wheel, an enthalpy wheel, and a vapor compression cycle (VCC), was investigated experimentally. This work also explored the use of a new type of desiccant material, which can be regenerated with a low temperature heat source. The experimental results showed that the hybrid A/C is more effective than the standalone VCC in maintaining the indoor conditions within the comfort zone. Using the experimental data, the COP of the hybrid A/C driven by a hybrid solar collector was found to be at least double that of the current solar A/Cs. The innovative integration of its subsystems allows each subsystem to do what it can do best. That leads to lower energy consumption which helps reduce the peak electrical loads on electric utilities and reduces the consumer operating cost since less energy is purchased during the on peak periods and less solar collector area is needed. In order for the proposed A/C to become a real alternative to conventional systems, its performance and total cost were optimized using the experimentally validated model. The results showed that for an

  7. Probing radiation damage by alternated current conductivity as a method to characterize electron hopping conduction in DNA molecules

    NASA Astrophysics Data System (ADS)

    Gomes, Paulo J.; Coelho, Margarida; Dionísio, Madalena; António Ribeiro, Paulo; Raposo, Maria

    2012-09-01

    Analysis of AC electrical conductivity of deoxyribonucleic acid (DNA) thin films, irradiated with ultraviolet (UV) light, revealed that electrical conduction arises from DNA chain electron hopping between base-pairs and phosphate groups. The hopping distance calculated from correlated barrier hopping model equals the distance between DNA base-pairs, which is consistent with the loss of conductivity with irradiation time arising from a decrease in phosphates groups. In the high frequency regime, at a given frequency, real part of conductivity strongly depends on irradiation time particularly for low dose levels suggesting the use of DNA based films for UV radiation sensors.

  8. Probing radiation damage by alternated current conductivity as a method to characterize electron hopping conduction in DNA molecules

    SciTech Connect

    Gomes, Paulo J.; Coelho, Margarida; Antonio Ribeiro, Paulo; Raposo, Maria; Dionisio, Madalena

    2012-09-17

    Analysis of AC electrical conductivity of deoxyribonucleic acid (DNA) thin films, irradiated with ultraviolet (UV) light, revealed that electrical conduction arises from DNA chain electron hopping between base-pairs and phosphate groups. The hopping distance calculated from correlated barrier hopping model equals the distance between DNA base-pairs, which is consistent with the loss of conductivity with irradiation time arising from a decrease in phosphates groups. In the high frequency regime, at a given frequency, real part of conductivity strongly depends on irradiation time particularly for low dose levels suggesting the use of DNA based films for UV radiation sensors.

  9. A 100-kW three-phase ac plasma furnace for spheroidization of aluminum silicate particles

    SciTech Connect

    Gold, D.; Bonet, C.; Chauvin, G.; Geinaert, G.; Mathieu, A.C.; Millet, J.

    1981-06-01

    A 100-kW three-phase ac plasma furnace with sheathed copper electrodes (sheathing gas: air) is presented. It is used for spheroidizing ''chamotte'' (refractory-fired clay) particles having a smooth, pore-free surface. A simple, one-dimensional numerical model for the heat transfer to the particles explains the maximum processing rate and the detrimental influence of an inhomogeneous particle size distribution.

  10. Transport conductivity of graphene at RF and microwave frequencies

    NASA Astrophysics Data System (ADS)

    Awan, S. A.; Lombardo, A.; Colli, A.; Privitera, G.; Kulmala, T. S.; Kivioja, J. M.; Koshino, M.; Ferrari, A. C.

    2016-03-01

    We measure graphene coplanar waveguides from direct current (DC) to a frequency f = 13.5 GHz and show that the apparent resistance (in the presence of parasitic impedances) has an {ω }2 dependence (where ω =2π f), but the intrinsic conductivity (without the influence of parasitic impedances) is frequency-independent. Consequently, in our devices the real part of the complex alternating current (AC) conductivity is the same as the DC value and the imaginary part is ˜0. The graphene channel is modeled as a parallel resistive-capacitive network with a frequency dependence identical to that of the Drude conductivity with momentum relaxation time ˜2.1 ps, highlighting the influence of AC electron transport on the electromagnetic properties of graphene. This can lead to optimized design of high-speed analog field-effect transistors, mixers, frequency doublers, low-noise amplifiers and radiation detectors.

  11. Air Pollution.

    ERIC Educational Resources Information Center

    Scorer, Richard S.

    The purpose of this book is to describe the basic mechanisms whereby pollution is transported and diffused in the atmosphere. It is designed to give practitioners an understanding of basic mechanics and physics so they may have a correct basis on which to formulate their decisions related to practical air pollution control problems. Since many…

  12. Air Pollution

    PubMed Central

    Clifton, Marjorie

    1964-01-01

    Dr Marjorie Clifton describes the classification of gaseous and nongaseous constituents of air pollution and then outlines the methods of measuring these. The National Survey embraced 150 towns of all sizes throughout England and Wales and provided data on smoke and sulphur dioxide in relation to climate, topography, industrialization, population density, fuel utilization and urban development. Dr W C Turner discusses the relationship between air pollution and mortality from respiratory conditions, and particularly the incidence of chronic bronchitis. He postulates a theory that such respiratory conditions arise as an allergy to the spores of certain moulds, spore formation being encouraged by the air humidity in Greatv Britain and overcrowded and damp living conditions. He describes the results of a twenty-week study undertaken in 1962-3, showing associations between respiratory disease and levels of air pollution. Dr Stuart Carne undertook a survey in general practice to plot the patterns of respiratory illness in London during the winter of 1962-3. There were two peaks of respiratory illnesses coinciding with the fog at the beginning of December and the freeze-up from the end of December until the beginning of March. PMID:14178955

  13. Discrete conductance switching in conducting polymer wires

    NASA Astrophysics Data System (ADS)

    He, H. X.; Li, X. L.; Tao, N. J.; Nagahara, L. A.; Amlani, I.; Tsui, R.

    2003-07-01

    Charge transport in conducting polymers (polyaniline and polypyrrole) bridged between two gold nanoelectrodes separated with a nanoscale gap (varying from ˜1 nm to a few tens of nm was studied by controlling the polymer redox states electrochemically. In sharp contrast to the macroscopic samples, the conductance switches abruptly between insulating (off) and conducting (on) states like a telegraphic signal. The time durations of the on and off states depend on the potential of the nanoelectrodes, indicating the important role of the redox states in the signal. We attribute the telegraphic signal to the fluctuation between the insulating reduced state and conducting oxidized state of the polymer, which rises as electrons trap into the oxidized state and escape from the reduced state.

  14. Aerodynamical sealing by air curtains

    NASA Astrophysics Data System (ADS)

    Frank, Daria; Linden, Paul

    2015-11-01

    Air curtains are artificial high-velocity plane turbulent jets which are installed in a doorway in order to reduce the heat and the mass exchange between two environments. The performance of an air curtain is assessed in terms of the sealing effectiveness E, the fraction of the exchange flow prevented by the air curtain compared to the open-door situation. The main controlling parameter for air curtain dynamics is the deflection modulus Dm representing the ratio of the momentum flux of the air curtain and the transverse forces acting on it due to the stack effect. In this talk, we examine the influence of two factors on the performance of an air curtain: the presence of an additional ventilation pathway in the room, such as a small top opening, and the effects of an opposing buoyancy force which for example arises if a downwards blowing air curtain is heated. Small-scale experiments were conducted to investigate the E (Dm) -curve of an air curtain in both situations. We present both experimental results and theoretical explanations for our observations. We also briefly illustrate how simplified models developed for air curtains can be used for more complex phenomena such as the effects of wind blowing around a model building on the ventilation rates through the openings.

  15. AC corrosion -- A new challenge to pipeline integrity

    SciTech Connect

    Gummow, R.A.; Wakelin, R.G.; Segall, S.M.

    1998-12-31

    Corrosion of steel by alternating current was investigated as far back as the early 1900`s. These early studies and others in the 1950--60`s indicated that AC corrosion of steel was only a fraction of an equivalent amount of direct current (i.e. less than 1% of a like amount of DC) and in addition was controlled to negligible levels when cathodic protection was applied to industry standards. In 1986 however, an investigation into a corrosion failure on a high pressure gas pipeline in Germany indicated that the sole cause of the failure was AC corrosion. This corrosion failure on an otherwise well protected pipeline resulted in the initiation of several laboratory and field studies which indicated, that above a certain minimum AC current density, normal levels of cathodic protection will not control AC corrosion to acceptable levels and that AC mitigation is often required to prevent serious corrosion. Several other AC corrosion sites were discovered at coating holidays during the follow-up investigations in Germany. A graph, relating AC voltage to holiday size at the minimum AC current density for corrosion, is presented to assist the pipeline operator in determining whether or not a pipeline is susceptible to AC corrosion activity.

  16. AC corrosion -- a new threat to pipeline integrity?

    SciTech Connect

    Gummow, R.A.; Wakelin, R.G.; Segall, S.M.

    1996-12-31

    Corrosion of steel by alternating current was investigated as far back as the early 1900`s. These early studies and others in the 1950--60`s indicated that AC corrosion of steel was only a fraction of an equivalent amount of direct current (i.e., less than 1% of a like amount of DC) and in addition was controlled to negligible levels with cathodic protection applied to industry standards. In 1986 however, an investigation into a corrosion failure on a high pressure gas pipeline in Germany indicated that the sole cause of the failure was AC corrosion. This corrosion failure on an otherwise well protected pipeline resulted in several laboratory and field studies which indicated, that above a certain minimum AC current density, standard levels of cathodic protection will not control AC corrosion and AC mitigation is required to prevent further corrosion. Several other corrosion anomalies were discovered at coating holidays during the follow-up investigations in Germany. The authors have investigated several corrosion occurrences on pipelines in Ontario during the last 2--3 years which appear to be caused by AC corrosion. This presentation traces the literature record on AC electrolysis from the past to the present and discusses the key parameters which determine the likelihood of corrosion attack. Several case histories of suspected AC corrosion will be discussed and guidelines on how to assess whether or not a pipeline is susceptible to AC corrosion will be offered.

  17. Fabrication of alumina films with laminated structures by ac anodization

    NASA Astrophysics Data System (ADS)

    Segawa, Hiroyo; Okano, Hironaga; Wada, Kenji; Inoue, Satoru

    2014-02-01

    Anodization techniques by alternating current (ac) are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50-200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials.

  18. Conducting Compositions of Matter

    NASA Technical Reports Server (NTRS)

    Viswanathan, Tito (Inventor)

    2001-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

  19. Conducting Compositions of Matter

    NASA Technical Reports Server (NTRS)

    Viswanathan, Tito (Inventor)

    1999-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

  20. Conducting compositions of matter

    NASA Technical Reports Server (NTRS)

    Viswanathan, Tito (Inventor)

    2000-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.