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Sample records for ac electroosmosis aceo

  1. 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

  2. Enhanced penetration of fluoride particles into bovine enamel by combining dielectrophoresis with AC electroosmosis.

    PubMed

    Ivanoff, Chris S; Swami, Nathan S; Hottel, Timothy L; Garcia-Godoy, Franklin

    2013-11-01

    Fluoride deposition into the pores of enamel is necessary at high concentrations to reduce enamel demineralization and with a high degree of penetration to account for loss by ingestion. Current diffusion and electrochemical methods are inadequate for effectively transporting fluoride greater than 20 μm into enamel. The study explores the coupling of dielectrophoresis (DEP) and AC electroosmosis (ACEO) to selectively concentrate fluoride particles from fluoride gel excipients and enhance their penetration into enamel. By measuring the frequency response of approximately 10-μm-sized sodium fluoride particles in an aqueous gel media, appropriate frequencies for positive DEP, negative DEP, and ACEO are identified. An assembly composed of two cross-planar interdigitated electrode (IDE) arrays with open slots is driven successively by fields at appropriate frequencies to drive fluoride particles through the slots of the IDE and into the enamel pores using a combination of DEP and ACEO methods. Fluoride uptake and penetration of 1.23% acidulated phosphate fluoride gel into bovine tooth enamel at various depths is measured using wavelength dispersive spectrometry to compare deposition by diffusion, DEP, and DEP plus ACEO. Fluoride levels in all DEP groups were significantly higher than diffusion groups at depths 10 and 20 μm. The highest fluoride concentrations at 10, 20, 50, and 100 μm depths occur under deposition conditions combining DEP with ACEO. Fluoride levels at 50 μm were equivalent to long-term prophylactic exposure. These methods may potentially benefit populations at high risk for development of caries and periodontal disease, including underserved children and disparate groups. PMID:23897721

  3. Combination of ac electroosmosis and dielectrophoresis for particle manipulation on electrically-induced microscale wave structures

    NASA Astrophysics Data System (ADS)

    Chung, Cheng-Che; Glawdel, Tomasz; Ren, Carolyn L.; Chang, Hsien-Chang

    2015-03-01

    This work presents a simple method to fabricate controllable microscale wave structures on the top of regular interdigitated electrode (IDE) arrays using electrically-assisted lithography techniques. Smooth wave structures are extremely difficult, if not impossible, to fabricate using traditional multilayer photolithography technology. The fabricated wave structures were carefully measured using an optical profiler and the measured wave profiles were used in the numerical simulation of electrical field and for evaluating the parameters influencing the fabricated wave structure. It is demonstrated that the combined smooth wave structure and IDE array offer unique capability for particle manipulation including particle concentration, aggregation and separation. Particle motion manipulated via the combined wave structure and IDE array is governed by ac electroosmosis (ACEO), dielectrophoresis (DEP) or a combination of both depending on the applied frequency. At lower frequencies (~30 kHz), ACEO dominates and particles are driven to move along the valleys of the wave structures; while at higher frequencies (~200 kHz), DEP force dominates which concentrates particles at the peaks of the wave structures. In addition, varying the ac waveform from sine-wave to square-wave allows for dynamic control of particle motion. Size-dependent particle separation over the wave structure is also demonstrated for a mixture of 0.5 µm and 2 µm particles that are separated into two populations by the joint effects of drag and DEP forces when being pumped to flow via ACEO.

  4. 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.

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

    PubMed

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

    2011-09-01

    We used the Maxwell stress tensor method to understand dielectrophoretic particle-particle interactions and applied the results to the interpretation of particle behaviors under alternating current (AC) electrohydrodynamic conditions such as AC electroosmosis (ACEO) and electrothermal flow (ETF). Distinct particle behaviors were observed under ACEO and ETF. Diverse particle-particle interactions observed in experiments such as particle clustering, particles keeping a certain distance from each other, chain and disc formation and their rotation, are explained based on the numerical simulation data. The improved understanding of particle behaviors in AC electrohydrodynamic flows presented here will enable researchers to design better particle manipulation strategies for lab-on-a-chip applications. PMID:21823132

  6. Electrodeposition of Au/Ag bimetallic dendrites assisted by Faradaic AC-electroosmosis flow

    SciTech Connect

    Ji, Jianlong; Li, Pengwei; Sang, Shengbo Zhang, Wendong Li, Gang; Hu, Jie; Zhou, Zhaoying Yang, Xing; Dong, Hualai

    2014-03-15

    Au/Ag bimetallic dendrites were synthesized successfully from the corresponding aqueous solution via the AC electrodeposition method. Both of the morphologies and compositions could be tuned by the electrolyte concentration and AC frequency. The prepared bimetallic dendrites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and UV–vis spectroscopy. The underlying dendrite growth mechanism was then proposed in the context of the Directed Electrochemical Nanowires Assembly (DENA) models. Owing to the unscreened voltage dropping in the electrolyte bulk, electromigration dominates the species flux process, and cations tend to accumulate in areas with strong electric field intensity, such as electrode edges. Moreover, Faradaic AC-electro-osmosis (ACEO) flow could increase the effective diffusion layer thickness in these areas during the electrochemical reaction, and leads to dendrite growth. Further Micro-Raman observations illustrated that the Au/Ag bimetallic dendrites exhibited pronounced surface-enhanced Raman scattering (SERS) activity, using 4-mercaptopyridine (4-MP) as model molecules.

  7. Electrodeposition of Au/Ag bimetallic dendrites assisted by Faradaic AC-electroosmosis flow

    NASA Astrophysics Data System (ADS)

    Ji, Jianlong; Li, Pengwei; Sang, Shengbo; Zhang, Wendong; Zhou, Zhaoying; Yang, Xing; Dong, Hualai; Li, Gang; Hu, Jie

    2014-03-01

    Au/Ag bimetallic dendrites were synthesized successfully from the corresponding aqueous solution via the AC electrodeposition method. Both of the morphologies and compositions could be tuned by the electrolyte concentration and AC frequency. The prepared bimetallic dendrites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and UV-vis spectroscopy. The underlying dendrite growth mechanism was then proposed in the context of the Directed Electrochemical Nanowires Assembly (DENA) models. Owing to the unscreened voltage dropping in the electrolyte bulk, electromigration dominates the species flux process, and cations tend to accumulate in areas with strong electric field intensity, such as electrode edges. Moreover, Faradaic AC-electro-osmosis (ACEO) flow could increase the effective diffusion layer thickness in these areas during the electrochemical reaction, and leads to dendrite growth. Further Micro-Raman observations illustrated that the Au/Ag bimetallic dendrites exhibited pronounced surface-enhanced Raman scattering (SERS) activity, using 4-mercaptopyridine (4-MP) as model molecules.

  8. Lateral separation of colloids or cells by dielectrophoresis augmented by AC electroosmosis.

    PubMed

    Zhou, Hao; White, Lee R; Tilton, Robert D

    2005-05-01

    Colloidal particles and biological cells are patterned and separated laterally adjacent to a micropatterned electrode array by applying AC electric fields that are principally oriented normally to the electrode array. This is demonstrated for yeast cells, red blood cells, and colloidal polystyrene particles of different sizes and zeta-potentials. The separation mechanism is observed experimentally to depend on the applied field frequency and voltage. At high frequencies, particles position themselves in a manner that is consistent with dielectrophoresis, while at low frequencies, the positioning is explained in terms of a strong coupling between gravity, the vertical component of the dielectrophoretic force, and the Stokes drag on particles induced by AC electroosmotic flow. Compared to high frequency dielectrophoretic separations, the low frequency separations are faster and require lower applied voltages. Furthermore, the AC electroosmosis coupling with dielectrophoresis may enable cell separations that are not feasible based on dielectrophoresis alone. PMID:15797412

  9. Effect of the combined action of Faradaic currents and mobility differences in ac electro-osmosis

    NASA Astrophysics Data System (ADS)

    González, A.; Ramos, A.; García-Sánchez, P.; Castellanos, A.

    2010-01-01

    In this work, we extend previous analyses of ac electro-osmosis to account for the combined action of two experimentally relevant effects: (i) Faradaic currents from electrochemical reactions at the electrodes and (ii) differences in ion mobilities of the electrolyte. In previous works, the ac electro-osmotic motion has been analyzed theoretically under the assumption that only forces in the diffuse (Debye) layer are relevant. Here, we first show that if the ion mobilities of a 1-1 aqueous solution are different, the charged zone expands from the Debye layer to include the diffusion layer. We later include the Faradaic currents and, as an attempt to explore both factors simultaneously, we perform a thin-layer, low-frequency, linear analysis of the system. Finally, the model is applied to the case of an electrolyte actuated by a traveling-wave signal. A steady liquid motion in opposite direction to the applied signal is predicted for some ranges of the parameters. This could serve as a partial explanation for the observed flow reversal in some experiments.

  10. Fabrication of Out-of-Plane Electrodes for ACEO Pumps

    NASA Astrophysics Data System (ADS)

    Senousy, Yehya; Harnett, Cindy

    2012-02-01

    This abstract reports the fabrication process of a novel AC Electrosmosis (ACEO) pump with out of plane asymmetric interdigitated electrodes. A self-folding technique is used to fabricate the electrodes, that depends on the strain mismatch between the tensile stressed film (metal layer) and the compressive stress film (oxidized silicon layer). The electrodes roll up with a well-defined radius of curvature in the range of 100-200 microns. Two different electrical signals are connected to alternating electrodes using an insulating silicon nitride barrier that allows circuits to cross over each other without shorting. Electroosmotic micropumps are essential for low-cost, power-efficient microfluidic lab-on-chip devices used in diverse application such as analytical probes, drug delivery systems and surgical tools. ACEO pumps have been developed to address the drawbacks of the DCEO pumps such as the faradic reaction and gas bubbles. The original ACEO microfluidic pump was created with planar arrays of asymmetric interdigitated electrodes at the bottom of the channel. This rolled-up tube design improves on the planar design by including the channel walls and ceiling in the active pumping surface area of the device.

  11. Large distance liquid pumping by AC electro-osmosis for the delivery of biological cells and reagents in microfluidic devices

    NASA Astrophysics Data System (ADS)

    Lee, Daniel; Xu, Guolin; Tng, Yongsheng; Htet, Kyaw Zin; Yang, Chun; Ying, Jackie Y.

    2008-03-01

    Liquid pumping, mixing and biological cells/reagents delivery in micro- or nano-liter volume is critical in lab-on-chip systems. We describe a novel AC electro-osmosis device for delivering reagents/cells over large distances without a global pressure gradient. Our device features facile transport range scalability in x- and y-axes, using continuous flow in a serpentine microchannel realized by microelectrode pairs arrayed in a unique antiparallel-asymmetric configuration. Co-planar microelectrodes on glass substrate are fabricated from gold with chromium as seed layer using micro-electromechanical system (MEMS) technology. Sealed upon the micro-electrodes is an open-ended serpentine microchannel having width 80μm and depth 45μm formed by micromolding PDMS with a silicon-based mold. AC signals at 3.5V pp and 0.5V DC offset is used to energize the microelectrodes, and polystyrene beads with diameter 5.0μm are used as tracer particles to visualize flow. Maximum velocity of 871 μm/s was recorded using AC signals at 8 kHz. The ease of scaling up transport distance range in 2-axes is unique to our device. Scalability in x-axis is achieved by varying the number of microelectrode pairs; and in y-axis by varying the number of microelectrodes iterations and the corresponding number of turns in the serpentine microchannel. Being scalable in transporting fluidic volume with high efficiency under small driving voltages makes our device suitable for miniaturization in a micro-total-analytical-system. Our device could be applied towards multiple point reagents, biological cells and particles delivery and mixing in a lab-on-chip.

  12. Direct simulation of phase delay effects on induced-charge electro-osmosis under large ac electric fields.

    PubMed

    Sugioka, Hideyuki

    2016-08-01

    The standard theory of induced-charge electro-osmosis (ICEO) often overpredicts experimental values of ICEO velocities. Using a nonsteady direct multiphysics simulation technique based on the coupled Poisson-Nernst-Planck and Stokes equations for an electrolyte around a conductive cylinder subject to an ac electric field, we find that a phase delay effect concerning an ion response provides a fundamental mechanism for electrokinetic suppression. A surprising aspect of our findings is that the phase delay effect occurs even at much lower frequencies (e.g., 50 Hz) than the generally believed charging frequency of an electric double layer (typically, 1 kHz) and it can decrease the electrokinetic velocities in one to several orders. In addition, we find that the phase delay effect may also cause a change in the electrokinetic flow directions (i.e., flow reversal) depending on the geometrical conditions. We believe that our findings move toward a more complete understanding of complex experimental nonlinear electrokinetic phenomena.

  13. Direct simulation of phase delay effects on induced-charge electro-osmosis under large ac electric fields

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2016-08-01

    The standard theory of induced-charge electro-osmosis (ICEO) often overpredicts experimental values of ICEO velocities. Using a nonsteady direct multiphysics simulation technique based on the coupled Poisson-Nernst-Planck and Stokes equations for an electrolyte around a conductive cylinder subject to an ac electric field, we find that a phase delay effect concerning an ion response provides a fundamental mechanism for electrokinetic suppression. A surprising aspect of our findings is that the phase delay effect occurs even at much lower frequencies (e.g., 50 Hz) than the generally believed charging frequency of an electric double layer (typically, 1 kHz) and it can decrease the electrokinetic velocities in one to several orders. In addition, we find that the phase delay effect may also cause a change in the electrokinetic flow directions (i.e., flow reversal) depending on the geometrical conditions. We believe that our findings move toward a more complete understanding of complex experimental nonlinear electrokinetic phenomena.

  14. Direct simulation of phase delay effects on induced-charge electro-osmosis under large ac electric fields.

    PubMed

    Sugioka, Hideyuki

    2016-08-01

    The standard theory of induced-charge electro-osmosis (ICEO) often overpredicts experimental values of ICEO velocities. Using a nonsteady direct multiphysics simulation technique based on the coupled Poisson-Nernst-Planck and Stokes equations for an electrolyte around a conductive cylinder subject to an ac electric field, we find that a phase delay effect concerning an ion response provides a fundamental mechanism for electrokinetic suppression. A surprising aspect of our findings is that the phase delay effect occurs even at much lower frequencies (e.g., 50 Hz) than the generally believed charging frequency of an electric double layer (typically, 1 kHz) and it can decrease the electrokinetic velocities in one to several orders. In addition, we find that the phase delay effect may also cause a change in the electrokinetic flow directions (i.e., flow reversal) depending on the geometrical conditions. We believe that our findings move toward a more complete understanding of complex experimental nonlinear electrokinetic phenomena. PMID:27627362

  15. Fabrication and study of AC electro-osmotic micropumps

    NASA Astrophysics Data System (ADS)

    Guo, Xin

    In this thesis, microelectrode arrays of micropumps have been designed, fabricated and characterized for transporting microfluid by AC electro-osmosis (ACEO). In particular, the 3D stepped electrode design which shows superior performance to others in literature is adopted for making micropumps, and the performance of such devices has been studied and explored. A novel fabrication process has also been developed in the work, realizing 3D stepped electrodes on a flexible substrate, which is suitable for biomedical use, for example glaucoma implant. There are three major contributions to ACEO pumping in the work. First, a novel design of 3D "T-shaped" discrete electrode arrays was made using PolyMUMPsRTM process. The breakthrough of this work was discretizing the continuous 3D stepped electrodes which were commonly seen in the past research. The "T-shaped" electrodes did not only create ACEO flows on the top surfaces of electrodes but also along the side walls between separated electrodes. Secondly, four 3D stepped electrode arrays were designed, fabricated and tested. It was found from the experiment that PolyMUMPsRTM ACEO electrodes usually required a higher driving voltage than gold electrodes for operation. It was also noticed that a simulation based on the modified model taking into account the surface oxide of electrodes showed a better agreement with the experimental results. It thus demonstrated the possibility that the surface oxide of electrodes had impact on fluidic pumping. This methodology could also be applied to metal electrodes with a native oxide layer such as titanium and aluminum. Thirdly, a prototype of the ACEO pump with 3D stepped electrode arrays was first time realized on a flexible substrate using Kapton polyimide sheets and packaged with PDMS encapsulants. Comprehensive experimental testing was also conducted to evaluate the mechanical properties as well as the pumping performance. The experimental findings indicated that this fabrication

  16. Electroosmosis in Nitella.

    PubMed

    BLINKS, L R; AIRTH, R L

    1957-11-20

    The role of electroosmosis was studied directly in Nitella. The cells were mounted in a water-tight barrier between two chambers containing reversible electrodes for the application of potentials, and fitted with calibrated capillaries to measure water movement. No water movement was found when small existing bioelectric potentials were short-circuited through an external connection, nor when external potentials up to 1 or 2 volts were applied (producing currents up to 5 microa). Higher potentials (up to 10 volts) caused small movements of water, toward the negative pole. Larger and often irreversible water movements were produced by potentials up to 20 volts-sometimes persisting after current flow. A variety of evidence suggests that the effects are caused by injury at the cathodal end of the cell, allowing water to be attracted osmotically at the intact end and forced out at the injured end (transosmosis). This injury is reversible under small applied potentials, irreversible after large ones (100 to 200 times the natural bioelectric values). Such water flows persist in low salt concentrations (up to 0.09 M NaCl) but almost completely vanish in isotonic (0.26 M) mannitol. This confirms the osmotic, rather than the electroosmotic nature of the water movement. It is estimated that electroosmosis cannot account for more than 1 per cent of the water movement (or turgor) in Nitella cells. The dead cellulose walls display a small electroosmotic water flow at very high current densities (under 20 volts applied potential).

  17. Decontamination of soil using electro-osmosis

    SciTech Connect

    Hamed, J.T.

    1990-01-01

    A theory is presented for pH gradient development by diffusion and convection in electrokinetic processing of soils. The premises and consequences of the theory are discussed. Based upon this theory, a mathematical model is developed to predict the pH gradient development in electro-osmosis. Electro-osmosis tests are conducted on saturated kaolinite specimens loaded with Pb(II), Cd(II), and Cr(III) to investigate the feasibility, efficiency, and energy requirements of the process in removal of heavy metals. The test results pertaining to the flow and the associated electrochemistry are presented. Tests indicated that the flow in electro-osmosis with open electrodes is time-dependent and it is strongly influenced by electrochemistry generated as a result of the prevailing pH gradients. High removal efficiency, up to 95%, was achieved on kaolinite specimens loaded with Pb(II) up to 1000 [mu]g/g of soil. Also the removing efficiency was very high for kaolinite specimens loaded with Cd(II) up to 120 mg/g of dry soil. However, tests conducted on kaolinite loaded with Cr(III) indicated that only 60 to 70% of absorbed Cr(III) was removed from the anode zone. The influence of fundamental variables affecting the chemistry and efficiency of the process such as the current density, the voltage gradient and contaminant concentration are also investigated and presented.

  18. Induced charge electroosmosis micropumps using arrays of Janus micropillars.

    PubMed

    Paustian, Joel S; Pascall, Andrew J; Wilson, Neil M; Squires, Todd M

    2014-09-01

    We report on a microfluidic AC-driven electrokinetic pump that uses Induced Charge Electro-Osmosis (ICEO) to generate on-chip pressures. ICEO flows occur when a bulk electric field polarizes a metal object to induce double layer formation, then drives electroosmotic flow. A microfabricated array of metal-dielectric Janus micropillars breaks the symmetry of ICEO flow, so that an AC electric field applied across the array drives ICEO flow along the length of the pump. When pumping against an external load, a pressure gradient forms along the pump length. The design was analyzed theoretically with the reciprocal theorem. The analysis reveals a maximum pressure and flow rate that depend on the ICEO slip velocity and micropillar geometry. We then fabricate and test the pump, validating our design concept by demonstrating non-local pressure driven flow using local ICEO slip flows. We varied the voltage, frequency, and electrolyte composition, measuring pump pressures of 15-150 Pa. We use the pump to drive flows through a high-resistance microfluidic channel. We conclude by discussing optimization routes suggested by our theoretical analysis to enhance the pump pressure. PMID:25000878

  19. Ultrafast high-pressure AC electro-osmotic pumps for portable biomedical microfluidics.

    PubMed

    Huang, Chien-Chih; Bazant, Martin Z; Thorsen, Todd

    2010-01-01

    This paper details the development of an integrated AC electro-osmotic (ACEO) microfluidic pump for dilute electrolytes consisting of a long serpentine microchannel lined with three dimensional (3D) stepped electrode arrays. Using low AC voltage (1 V rms, 1 kHz), power (5 mW) and current (4.5 mA) in water, the pump is capable of generating a 1.3 kPa head pressure, a 100-fold increase over prior ACEO pumps, and a 1.3 mm/s effective slip velocity over the electrodes without flow reversal. The integrated ACEO pump can utilize low ionic strength solutions such as distilled water as the working solution to pump physiological strength (100 mM) biological solutions in separate microfluidic devices, with potential applications in portable or implantable biomedical microfluidic devices. As a proof-of-concept experiment, the use of the ACEO pumps for DNA hybridization in a microfluidic microarray is demonstrated. PMID:20024054

  20. Polymer Coatings Reduce Electro-osmosis

    NASA Technical Reports Server (NTRS)

    Herren, Blair J.; Snyder, Robert; Shafer, Steven G.; Harris, J. Milton; Van Alstine, James M.

    1989-01-01

    Poly(ethylene glycol) film controls electrostatic potential. Electro-osmosis in quartz or glass chambers reduced or reversed by coating inside surface of chambers with monomacromolecular layers of poly(ethylene glycol). Stable over long times. Electrostatic potential across surface of untreated glass or plastic chamber used in electro-phoresis is negative and attracts cations in aqueous electrolyte. Cations solvated, entrains flow of electrolyte migrating toward cathode. Electro-osmotic flow interferes with desired electrophoresis of particles suspended in electrolyte. Polymer coats nontoxic, transparent, and neutral, advantageous for use in electrophoresis.

  1. Control of electroosmosis in coated quartz capillaries

    NASA Technical Reports Server (NTRS)

    Herren, Blair J.; Van Alstine, James; Snyder, Robert S.; Shafer, Steven G.; Harris, J. Milton

    1987-01-01

    The effectiveness of various coatings for controlling the electroosmotic fluid flow that hinders electrophoretic processes is studied using analytical particle microelectrophoresis. The mobilities of 2-micron diameter glass and polystyrene latex spheres (exhibiting both negative and zero effective surface charge) were measured in 2-mm diameter quartz capillaries filled with NaCl solutions within the 3.5-7.8 pH range. It is found that capillary inner surface coatings using 5000 molecular weight (or higher) poly(ethylene glycol): significantly reduced electroosmosis within the selected pH range, were stable for long time periods, and appeared to be more effective than dextran, methylcellulose, or silane coatings.

  2. Electroosmosis remediation of DNAPLS in low permeability soils

    SciTech Connect

    Ho, S V.

    1996-08-01

    Electroosmosis is the movement of water through a soil matrix induced by a direct current (DC) electric field. The technique has been used since the 1930s for dewatering and stabilizing fine-grained soils. More recently, electroosmosis has been considered as an in-situ method for soil remediation in which water is injected into the soil at the anode region to flush the contaminants to the cathode side for further treatment or disposal. The major advantage of electroosmosis is its inherent ability to move water uniformly through clayey, silty soils at 100 to 1000 times faster than attainable by hydraulic means, and with very low energy usage. Drawbacks of electroosmosis as a stand-alone technology include slow speed, reliance on solubilizing the contaminants into the groundwater for removal, potentially an unstable process for long term operation, and necessary additional treatment and disposal of the collected liquid. Possible remediation applications of electroosmosis for DNAPLs would be primarily in the removal of residual DNAPLs in the soil pores by electroosmotic flushing. The future of electroosmosis as a broad remedial method lies in how well it can be coupled with complementary technologies. Examples include combining electroosmosis with vacuum extraction, with surfactant usage to deal with non-aqueous phase liquids (NAPLs) through enhanced solubilization or mobilization, with permeability enhancing methods (hydrofracturing, pneumatic fracturing, etc.) to create recovery zones, and with in-situ degradation zones to eliminate aboveground treatment. 33 refs., 1 fig., 1 tab.

  3. Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus

    NASA Astrophysics Data System (ADS)

    Feng, Huicheng; Wong, Teck Neng; Che, Zhizhao; Marcos

    2016-06-01

    Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.

  4. Induced-charge electro-osmosis around metal and Janus spheres in water: Patterns of flow and breaking symmetries

    NASA Astrophysics Data System (ADS)

    Peng, Chenhui; Lazo, Israel; Shiyanovskii, Sergij V.; Lavrentovich, Oleg D.

    2014-11-01

    We establish experimentally the flow patterns of induced-charge electro-osmosis around immobilized metallic spheres in aqueous electrolyte. The ac field modifies local electrolyte concentration and causes quadrupolar flows with inward velocities being smaller than the outward ones. At high fields, the flow becomes irregular, with vortices smaller than the size of the sphere. Janus metallodielectric spheres create dipolar flows and pump the fluid from the dielectric toward the metallic part. The experimentally determined far-field flows decay with distance as r-3.

  5. CATION TRANSPORT AND PARTITIONING DURING A FIELD TEST OF ELECTROOSMOSIS

    EPA Science Inventory

    Field experiments were conducted to evaluate the effects of soil properties, such as the cation exchange capacity and mineral content, on pH, soluble ion concentrations, and electrical conductivity during electroosmosis in a silty clay soil. The soil is composed mainly of quartz ...

  6. TRANSPORT OF TRICHLOROETHYLENE (TCE) IN NATURAL SOIL BY ELECTROOSMOSIS

    EPA Science Inventory

    Contamination in low permeability soils poses a significant technical challenge to in-situ remediation, primarily due to low mobilization of the contaminants and difficulty in uniform delivery of treatment reagents. An alternative approach using electroosmosis (EO) is used to mob...

  7. Heat-transfer enhancement in AC electro-osmotic micro-flows

    NASA Astrophysics Data System (ADS)

    Liu, Z. P.; Speetjens, M. F. M.; Frijns, A. J. H.; van Steenhoven, A. A.

    2012-11-01

    Heat transfer in micro-flows is essential to emerging technologies as advanced microelectronics cooling systems and chemical processes in lab-on-a-chip applications. The present study explores the potential of AC electro-osmotic (ACEO) flow forcing, a promising technique for the actuation and manipulation of micro-flows, for heat-transfer enhancement. Subjects of investigation include the 3D flow structure due to ACEO forcing via an array of electrodes in a micro-channel by way of 3D velocity measurements. Presence and properties of vortical structures of the 3D flow are quantified in laboratory experiments. Typical outcomes of the experimental study result from a number of 3D particle trajectories obtained by using 3D micro-Particle-Tracking Velocimetry (3D μ-PTV). The steady nature of the flow enables combination of results from a series of measurements into one dense data set. This facilitates accurate evaluation of quantities relevant for heat transfer by data-processing methods. The primary circulation is given above one half of an electrode in terms of the spanwise component of vorticity. The outline of the vortex boundary is determined via the eigenvalues of the strain-rate tensor. To estimate convective heat transfer, wall shear rate above one half of an electrode is quantitatively analyzed as function of voltage amplitude and frequency. These results yield first insights into the characteristics of 3D ACEO flows and ways to exploit and manipulate them for heat-transfer enhancement.

  8. Electroosmosis effect on micro permeability through rock samples

    SciTech Connect

    Touchard G.; Paillat, T.; Beaufort, D.; Watanabe, S.

    1996-01-24

    It is a well known fact that a liquid flowing through a microporous media creates a potential difference between entry and exit of the sample. This phenomenon is known as streaming potential. In an other hand, when a potential difference is applied through an impregnate rock sample, a flow is induced, this is called electroosmosis effect. In this paper, we examine electroosmosis experiments made in a percolation cell in which two gold electrodes are placed in the inner and in the outer chamber. The temperature, the pressure and potential difference, the flow, the current and the chemical composition of water in chambers may be recorded. Experiment consist to the application of electric field through the sample and to observe the evolution of the flow, the electrical current and the chemical dissolution.

  9. Development of coatings to control electroosmosis in zero gravity electrophoresis

    NASA Technical Reports Server (NTRS)

    Krupnick, A. C.

    1974-01-01

    A major problem confronting the operation of free fluid electrophoresis in zero gravity is the control of electrokinetic phenomena and, in particular, electroosmosis. Due to the severity of counter flow as a result of electroosmosis, the electrical potential developed at the surface of shear must be maintained at near, or as close, to zero millivolts as possible. Based upon this investigation, it has been found that the amount of bound water or the degree of hydroxylation plays a major role in the control of this phenomenon. Based upon tests employing microcapillary electrophoresis, it has been found that gamma amino propyl trihydroxysilane produced a coating which provides the lowest potential (about 3.86 mV) at the surface of shear between the stationary and mobile layers.

  10. Molecular Dipole Osmosis Based on Induced Charge Electro-Osmosis

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2016-09-01

    We propose a novel mechanism of producing a large nonlinear electrokinetic vortex flow around a nonconductive polar molecule in an electrolyte. That is, a large nonlinear electrokinetic slip velocity is derived by considering a local giant permittivity due to a molecular electric dipole moment with induced-charge electro-osmosis (ICEO). Different from the conventional ICEO theory, our theory predicts that a nonconductive biomaterial, such as a base of a deoxyribonucleic acid (DNA) molecule, has a significantly high ICEO flow velocity because of its large local permittivity. We consider that our findings will contribute markedly to promising biomedical applications.

  11. Development of coatings to control electroosmosis in zero gravity electrophoresis

    NASA Technical Reports Server (NTRS)

    Krupnick, A. C.

    1974-01-01

    A major problem confronting the operation of free fluid electrophoresis in zero gravity is the control of electrokinetic phenomena and, in particular, electroosmosis. Due to the severity of counter flow, as a result of electroosmosis, the electrical potential developed at the surface of shear must be maintained at near, or as close to, zero millivolts as possible. Based upon this investigation, it has been found that the amount of bound water or the degree of hydroxylation plays a major role in the control of this phenomena. Of necessity, factors, such as adhesion, biocompatibility, protein adsorption, and insolubility were considered in this investigation because of the long buffer-coating exposure times required by present space operations. Based upon tests employing microcapillary electrophoresis, it has been found that gamma amino propyl trihydroxysilane produced a coating which provides the lowest potential (minus 3.86 mv) at the surface of shear between the stationary and mobile layers. This coating has been soaked in both borate and saline buffers, up to three months, in a pH range of 6.5 to 10 without deleterious effects or a change in its ability to control electrokinetic effects.

  12. Scaled particle focusing in a microfluidic device with asymmetric electrodes utilizing induced-charge electroosmosis.

    PubMed

    Ren, Yukun; Liu, Jiangwei; Liu, Weiyu; Lang, Qi; Tao, Ye; Hu, Qingming; Hou, Likai; Jiang, Hongyuan

    2016-08-01

    We propose a novel continuous-flow microfluidic particle concentrator with a specified focusing-particle number ratio (FR) at different channel outlets using induced-charge electroosmosis (ICEO). The particle-focusing region contains two floating electrodes of asymmetric widths L2 and L1 in the gap between a driving electrode pair, all of which are fabricated in parallel in the main channel. Applying an AC voltage over the driving electrodes, an ICEO flow with two vortexes can be induced over each of the two floating electrodes, and the actuation range of the ICEO vortex is proportional to the respective electrode size. We establish a preliminary physical model for the value of FR: at a moderate voltage and frequency range, FR approaches L2/L1 due to the scaled ICEO actuation range; by further modifying the voltage or frequency, FR is freely adjustable because of the variation in ICEO velocity. Furthermore, by connecting multiple focusing regions in series, i.e., high FR = (L2/L1)(n) can be conveniently generated in an n-stage flow focusing device. Our results provide a promising method for yielding transverse concentration gradients of particles useful in pre-processing before analysis. PMID:27354159

  13. Asymmetrical reverse vortex flow due to induced-charge electro-osmosis around carbon stacking structures

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2011-05-01

    Broken symmetry of vortices due to induced-charge electro-osmosis (ICEO) around stacking structures is important for the generation of a large net flow in a microchannel. Following theoretical predictions in our previous study, we herein report experimental observations of asymmetrical reverse vortex flows around stacking structures of carbon posts with a large height (~110 μm) in water, prepared by the pyrolysis of a photoresist film in a reducing gas. Further, by the use of a coupled calculation method that considers boundary effects precisely, the experimental results, except for the problem of anomalous flow reversal, are successfully explained. That is, unlike previous predictions, the precise calculations here show that stacking structures accelerate a reverse flow rather than suppressing it for a microfluidic channel because of the deformation of electric fields near the stacking portions; these structures can also generate a large net flow theoretically in the direction opposite that of a previous prediction for a standard vortex flow. Furthermore, by solving the one-dimensional Poisson-Nernst-Plank (PNP) equations in the presence of ac electric fields, we find that the anomalous flow reversal occurs by the phase retardation between the induced diffuse charge and the tangential electric field. In addition, we successfully explain the nonlinearity of the flow velocity on the applied voltage by the PNP analysis. In the future, we expect to improve the pumping performance significantly by using stacking structures of conductive posts along with a low-cost process.

  14. Electroosmosis in Membranes: Effects of Unstirred Layers and Transport Numbers

    PubMed Central

    Barry, P. H.; Hope, A. B.

    1969-01-01

    When a current is passed through a membrane system, differences in transport numbers between the membrane and the adjacent solutions will, in general, result in depletion and enhancement of concentrations at the membrane-solution interfaces. This will be balanced by diffusion back into the bulk solution, diffusion of solute back across the membrane itself, and osmosis resulting from these local concentration gradients. The two main results of such a phenomenon are (1) that there is a current-induced volume flow, which may be mistaken for electroosmosis, and (2) that there will generally develop transient changes in potential difference (PD) across membranes during and after the passage of current through them. PMID:5786317

  15. Stochastic rotation dynamics simulation of electro-osmosis

    NASA Astrophysics Data System (ADS)

    Ceratti, Davide R.; Obliger, Amaël; Jardat, Marie; Rotenberg, Benjamin; Dahirel, Vincent

    2015-09-01

    Stochastic Rotation Dynamics (SRD) is a mesoscale simulation technique that captures hydrodynamic couplings in simple and complex fluids. It can be used in various hydrodynamic regimes and it is not restricted to specific geometries. We show here that SRD using the collisional coupling approach to capture momentum transfer between the semi-implicit solvent and the explicit counterions, is able to describe electro-kinetic effects, i.e. coupled electrostatic and hydrodynamic phenomena occurring at charged solid-liquid interfaces. The method is first validated for electro-osmosis in the simple case of a slit pore without added salt, for which an analytical solution of the Helmholtz-Smoluchowski theory is known, in a physical regime where this mean-field theory is valid. We then discuss the predictions of SRD for electro-osmosis beyond the range of validity of the Helmholtz-Smoluchowski (or Poisson-Nernst-Planck) theory, in particular due to ion-ion correlations at the surface, to charge localisation on discrete sites at the solid surface and to surface charge heterogeneity, that all contribute to a reduction of the electro-osmotic flow. In order to disentangle these last two aspects, we also investigate at the mean-field level a simple system with alternate charged and neutral stripes, using lattice-Boltzmann electro-kinetics simulations. Overall, this work opens new perspectives for the use of SRD as a generic mesoscopic simulation method for soft matter problems, in particular under confinement, since in practice many interfaces between fluids and solids are charged.

  16. Membrane electroporation--fast molecular exchange by electroosmosis.

    PubMed

    Dimitrov, D S; Sowers, A E

    1990-03-01

    Human and rabbit erythrocyte ghosts loaded with FITC-dextran (mol. mass = 10 kDa) and NBD-glucosamine (mol. mass = 342 Da) in buffers of different ionic strength and composition were subjected to electric pulses (intensity 0.7 kV/mm and decay half-time 1 ms) at 7-10 degrees C and 20-24 degrees C. The transfer of the fluorescent dyes from the interior of the ghosts through the electropores was observed by low light level video microscopy. The pulses caused the fluorescence to appear outside the membranes as a transient cylindrical cloud directed toward the negative electrode during the first video frame (17 ms). It was similar in both rabbit and human erythrocyte ghosts and at both temperatures but differs for the two dyes, the fluorescence cylinder is long and tall for the FITC-dextran and relatively short and thick for the NBD-glucosamine. The molecular exchange was 2-3 orders of magnitude faster within the first 17 ms after the pulse than the diffusional exchange. It decreased with increasing ionic strength. Formulae for the transfer of molecules by electroosmotic flow through the pores are in agreement with these observations. They allow estimation of the total area of pores with radii larger than that of the fluorescent dye during the pulse. The major conclusion is that electroosmosis is the dominating mechanism of molecular exchange in electroporation of erythrocyte ghosts. PMID:1690573

  17. Elastic Beating Pump Using Induced-Charge Electro-osmosis

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2016-10-01

    Pumping a viscous liquid in a confined space is essential in microfluidic systems because the pressure-driven flow rate through small channels decreases with the third or fourth power of the channel size. Hence, inspired by a cilium's pumping ability in a confined space, we propose an elastic beating pump using a hydrodynamic force due to induced-charge electro-osmosis (ICEO) and numerically examine the pumping performance. By the multiphysics coupled simulation technique based on the boundary element method along with the thin double-layer approximation, we find that by selecting the optimum rigidity of the elastic beam, the ICEO elastic beating pump functions effectively at high frequencies with low applied voltages and shows a large average flow velocity with a remarkably large peak velocity that may be useful to flow a liquid with unexpectedly high viscosity. Furthermore, we propose a simple model that explains the characteristics of the time response behavior of the ICEO elastic beating pump tosome extent. By this analysis, we can considerably contribute to developments in studies on the artificial cilia having versatile functions.

  18. Elastic Valve Using Induced-Charge Electro-Osmosis

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2015-06-01

    Biomimic devices using induced-charge electro-osmosis (ICEO) is interesting since they have the possibility to realize high-performance functions with simple structures and with low-energy consumption. Thus, inspired by a cilium, we propose a two-dimensional artificial elastic valve using hydrodynamic force due to ICEO with a thin elastic beam in a microfluidic channel and numerically examine the valving performance. By an implicit strongly coupled simulation technique between a fluid and an elastic structure based on the boundary-element method, along with the thin-double-layer approximation, we realize stable calculations and find that the elastic valve using ICEO functions effectively at high frequency with low applied voltages in a realistic pressure flow. Further, we also examine passive motion of the valve; i.e., it stops a reverse flow effectively and releases a forward flow in the channel. We believe that our device can be used in a wide range of microfluidic applications, such as mixers, pumps, etc.

  19. Fabrication of an implantable stretchable electro-osmosis pump

    NASA Astrophysics Data System (ADS)

    Jahanshahi, A.; Axisa, F.; Vanfleteren, J.

    2011-02-01

    The aim of this paper is to demonstrate the feasibility of an implantable, low voltage driven microfluidic pump to deliver drugs. The micro pump has a high degree of biocompatibility and mechanical deformation capability, thanks to the use of elastic silicone elastomers (PDMS) for integration and embedding of the pump. We are using the new method of transverse DC electro-osmosis, which is demonstrated already in the literature. The method uses the fabrication of periodic grooves on top of the micro channel and the application of a DC voltage across the channel. In this contribution, for the first time the production and operation of soft elastic versions of such a pump, compatible with body tissue, is demonstrated. For the interconnects, gold is selectively electro-deposited on Cu-foil and is transferred to PDMS layer. Having only gold as the interconnect ascertains the high degree of bio-compatibility of the device. This pump works with voltages about 10V and produces mean flow speeds of about 60μm/s. The flow has also a helical profile which is a very good advantage to use this pump as a mixer for micro fluidic applications. Flow rate is measured by introducing dyed micro particles along with the liquid inside the channel.

  20. Electroosmosis-modulated peristaltic transport in microfluidic channels

    NASA Astrophysics Data System (ADS)

    Bandopadhyay, Aditya; Tripathi, Dharmendra; Chakraborty, Suman

    2016-05-01

    We analyze the peristaltic motion of aqueous electrolytes altered by means of applied electric fields. Handling electrolytes in typical peristaltic channel material such as polyvinyl chloride and Teflon leads to the generation of a net surface charge on the channel walls, which attracts counter-ions and repels co-ions from the aqueous solution, thus leading to the formation of an electrical double layer—a region of net charges near the wall. We analyze the spatial distribution of pressure and wall shear stress for a continuous wave train and single pulse peristaltic wave in the presence of an electrical (electroosmotic) body force, which acts on the net charges in the electrical double layer. We then analyze the effect of the electroosmotic body force on the particle reflux as elucidated through the net displacement of neutrally buoyant particles in the flow as the peristaltic waves progress. The impact of combined electroosmosis and peristalsis on trapping of a fluid volume (e.g., bolus) inside the travelling wave is also discussed. The present analysis goes beyond the traditional analysis, which neglects the possibility of coupling the net pumping of fluids due to peristalsis and allows us to derive general expressions for the pressure drop and flow rate in order to set up a general framework for incorporating flow control and actuation by simultaneous peristalsis and application of electric fields to aqueous solutions. It is envisaged that the results presented here may act as a model for the design of lab-on-a-chip devices.

  1. Enhanced particle trapping performance of induced charge electroosmosis.

    PubMed

    Tao, Ye; Ren, Yukun; Liu, Weiyu; Wu, Yupan; Jia, Yankai; Lang, Qi; Jiang, Hongyuan

    2016-05-01

    By increasing the number of floating electrodes or enlarging the width of single floating electrode, this work provides effective ways to strongly improve the particle trapping performance of induced charge electroosmosis (ICEO). Particle trapping with double or triple separate narrow floating electrodes increases the effective actuating range of ICEO flow and therefore enhance the optimum trapping ability to be 1.63 or 2.34 times of that with single narrow electrode (width of L=200μm), and the ideal trapping frequency is independent of the electrode number due to the mutual independence of electrochemical ion relaxation over each electrode. Furthermore, using a single wide floating electrode with the effective width equal to three separate narrow floating electrodes (L=600μm) instead of a single narrow one slightly lowers the ideal trapping frequency due to an increase in the characteristic polarization length, but the trapping performance is only up to 1.59 times of that with original single narrow electrode, implying that vertical channel confinement effect may severely suppresses the effective actuating range of ICEO flow and renders the trapping performance not as expected. Trapping experiments over wide floating electrode with different channel height were carried out, showing that the trapping performance increases by correctly increasing the channel height. PMID:26914414

  2. Use of hydrophilic polymer coatings for control of electroosmosis and protein adsorption

    NASA Technical Reports Server (NTRS)

    Harris, J. Milton

    1987-01-01

    The purpose of this project was to examine the utility of polyethylene glycol (PEG) and dextran coatings for control of electroosmosis and protein adsorption; electroosmosis is an important, deleterious process affecting electrophoretic separations, and protein adsorption is a factor which needs to be controlled during protein crystal growth to avoid multiple nucleation sites. Performance of the project required use of X-ray photoelectron spectroscopy to refine previously developed synthetic methods. The results of this spectroscopic examination are reported. Measurements of electroosmotic mobility of charged particles in appropriately coated capillaries reveals that a new, one-step route to coating capillaries gives a surface in which electroosmosis is dramatically reduced. Similarly, both PEG and dextran coatings were shown by protein adsorption measurements to be highly effective at reducing protein adsorption on solid surfaces. These results should have impact on future low-g electrophoretic and protein crystal growth experiments.

  3. EFFECTS OF ELECTROOSMOSIS ON SOIL TEMPERATURE AND HYDRAULIC HEAD: I. FIELD OBSERVATION

    EPA Science Inventory

    A field test to quantify the changes of soil temperature and hydraulic head during electroosmosis has been conducted. The anode (3.1 m x 3.4m) was created by laying pieces of titanium mesh coated with mixed metal oxides on tope of a 3 cm thick sand layer at a depth of 0.4 m. The ...

  4. EFFECTS OF ELECTROOSMOSIS ON SOIL TEMPERATURE AND HYDRAULIC HEAD: II. NUMERICAL SIMULATION

    EPA Science Inventory

    A numerical model to simulate the distributions of voltage, soil temperature, and hydraulic head during the field test of electroosmosis was developed. The two-dimensional governing equations for the distributions of voltage, soil temperature, and hydraulic head within a cylindri...

  5. EFFECTS OF ELECTROOSMOSIS ON SOIL TEMPERATURE AND HYDRAULIC HEAD: I. FIELD OBSERVATIONS

    EPA Science Inventory

    A field test to quantify the changes of soil temperature and hydraulic head during electroosmosis was conducted. The anode (3.1 m x 3.4 m) was created by laying pieces of titanium mesh coated with mixed metal oxides on top of a 3 cm thick sand layer at a depth of 0.4 m. The catho...

  6. Microscale solution manipulation using photopolymerized hydrogel membranes and induced charge electroosmosis micropumps

    NASA Astrophysics Data System (ADS)

    Paustian, Joel Scott

    Microfluidic technology is playing an ever-expanding role in advanced chemical and biological devices, with diverse applications including medical diagnostics, high throughput research tools, chemical or biological detection, separations, and controlled particle fabrication. Even so, local (microscale) modification of solution properties within microchannels, such as pressure, solute concentration, and voltage remains a challenge, and improved spatiotemporal control would greatly enhance the capabilities of microfluidics. This thesis demonstrates and characterizes two microfluidic tools to enhance local solution control. I first describe a microfluidic pump that uses an electrokinetic effect, Induced-Charge Electroosmosis (ICEO), to generate pressure on-chip. In ICEO, steady flows are driven by AC fields along metal-electrolyte interfaces. I design and microfabricate a pump that exploits this effect to generate on-chip pressures. The ICEO pump is used to drive flow along a microchannel, and the pressure is measured as a function of voltage, frequency, and electrolyte composition. This is the first demonstration of chip-scale flows driven by ICEO, which opens the possibility for ICEO pumping in self-contained microfluidic devices. Next, I demonstrate a method to create thin local membranes between microchannels, which enables local diffusive delivery of solute. These ``Hydrogel Membrane Microwindows'' are made by photopolymerizing a hydrogel which serves as a local ``window'' for solute diffusion and electromigration between channels, but remains a barrier to flow. I demonstrate three novel experimental capabilities enabled by the hydrogel membranes: local concentration gradients, local electric currents, and rapid diffusive composition changes. I conclude by applying the hydrogel membranes to study solvophoresis, the migration of particles in solvent gradients. Solvent gradients are present in many chemical processes, but migration of particles within these

  7. A study of electro-osmosis as applied to drilling engineering

    NASA Astrophysics Data System (ADS)

    Hariharan, Peringandoor Raman

    In the present research project. the application of the process of electro-osmosis has been extended to a variety of rocks during the drilling operation. Electro-osmosis has been utilized extensively to examine its influence in reducing (i) bit balling, (ii) coefficient of friction between rock and metal and (iii) bit/tool wear. An attempt has been made to extend the envelope of confidence in which electro-osmosis was found to be operating satisfactorily. For all the above cases the current requirements during electro-osmosis were identified and were recorded. A novel test method providing repeatable results has been developed to study the problem of bit balling in the laboratory through the design of a special metallic bob simulating the drill bit. A numerical parameter described as the Degree-of-Balling (DOB) defined by the amount of cuttings stuck per unit volume of rock cut for the same duration of time is being proposed as a means to quantitatively describe the balling process in the laboratory. Five different types of shales (Pierre I & II, Catoosa, Mancos and Wellington) were compared and evaluated for balling characteristics and to determine the best conditions for reducing bit balling with electro-osmosis in a variety of drilling fluids including fresh water, polymer solutions and field type drilling fluids. Through the design, fabrication and performing of experiments conducted with a model Bottom Hole Assembly (BHA). the feasibility of maintaining the drill bit separately at a negative potential and causing the current to flow through the rock back into the string through a near bit stabilizer has been demonstrated. Experiments conducted with this self contained arrangement for the application of electro-osmosis have demonstrated a substantial decrease in balling and increase in the rate of penetration (ROP) while drilling with both a roller cone and PDC microbit (1-1/4" dia.) in Pierre I and Wellington shales. It is believed that the results obtained

  8. Electroosmosis in a Finite Cylindrical Pore: Simple Models of End Effects

    PubMed Central

    2015-01-01

    A theoretical model of electroosmosis through a circular pore of radius a that traverses a membrane of thickness h is investigated. Both the cylindrical surface of the pore and the outer surfaces of the membrane are charged. When h ≫ a, end effects are negligible, and the results of full numerical computations of electroosmosis in an infinite pore agree with theory. When h = 0, end effects dominate, and computations again agree with analysis. For intermediate values of h/a, an approximate analysis that combines these two limiting cases captures the main features of computational results when the Debye length κ–1 is small compared with the pore radius a. However, the approximate analysis fails when κ–1 ≫ a, when the charge cloud due to the charged cylindrical walls of the pore spills out of the ends of the pore, and the electroosmotic flow is reduced. When this spilling out is included in the analysis, agreement with computation is restored. PMID:25020257

  9. Assessing PAH removal from clayey soil by means of electro-osmosis and electrodialysis.

    PubMed

    Lima, Ana T; Ottosen, Lisbeth M; Heister, Katja; Loch, J P Gustav

    2012-10-01

    Polycyclic aromatic hydrocarbons (PAH) are persistent and toxic contaminants which are difficult to remove from fine porous material like clayey soils. The present work aims at studying two electroremediation techniques for the removal of PAHs from a spiked natural silt soil from Saudi Arabia and a silty loam soil from The Netherlands which has been exposed to tar contamination for over 100 years. The two techniques at focus are electro-osmosis and electrodialysis. The latter is applied for the first time for the removal of PAH. The efficiency of the techniques is studied using these two soils, having been subjected to different PAH contact times. Two surfactants were used: the non-ionic surfactant Tween 80 and anionic surfactant sodium dodecyl sulphate (SDS) to aid desorption of PAHs from the soil. Results show a large discrepancy in the removal rates between spiked soil and long-term field contaminated soil, as expected. In spiked soil, electro-osmosis achieves up to 85% while electrodialysis accomplishes 68% PAH removal. In field contaminated soil, electro-osmosis results in 35% PAH removal whereas electrodialysis results in 79%. Short recommendations are derived for the up-scale of the two techniques.

  10. Theoretical examination of electroosmosis control with external radial electric field in capillary electrophoresis.

    PubMed

    Chen, Y; Zhu, Y

    1999-07-01

    The influence of an external radial electric field (E(R)) on electroosmosis in capillary electrophoresis was studied theoretically. Based on a Stern-like model, three basic equations were deduced, with only two unknown parameters of delta and psi(d) where delta is the distance between the flowing shear interface and the tube wall, while psi(d) is the potential at the starting point of diffuse layer. The new equations reveal that, to effectively regulate the electroosmosis at E(R) <3 x 10(8) V/m, buffer pH should be kept below 5. In a common case of E(R) <10(8) V/m, the buffer pH should be below 4, otherwise the flow direction of the electroosmosis cannot be reversed. A way to increase the working pH range lies in the use of chemically coated rather than bare tubes. As expected, small capillaries and low ionic strength are preferred.

  11. Active Vector Separation Using Induced Charge Electro-osmosis with Polarizable Obstacle Arrays

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2016-09-01

    Vector separation using obstacle post arrays is promising for various microfluidic applications. Here, we propose a novel active sieve using induced charge electro-osmosis (ICEO). By the multi-physics simulation technique based on the boundary element method combined with a thin electric double-layer approximation, we find that the active sieve having a polarizable post array shows excellent vector separation with dynamic size selectivity owing to the hydrodynamic interactions between the polarizable post array and the target particle. We consider that our separation device is useful for realizing innovative high-throughput biomedical systems with a simple structure.

  12. Transungual iontophoretic transport of polar neutral and positively charged model permeants: effects of electrophoresis and electroosmosis.

    PubMed

    Hao, Jinsong; Li, S Kevin

    2008-02-01

    Transungual iontophoretic transport of model neutral permeants mannitol (MA), urea (UR), and positively charged permeant tetraethylammonium ion (TEA) across fully hydrated human nail plates at pH 7.4 were investigated in vitro. Four protocols were involved in the transport experiments with each protocol divided into stages including passive and iontophoresis transport of 0.1 and 0.3 mA. Water and permeant uptake experiments of nail clippings were also conducted to characterize the hydration and binding effects of the permeants to the nails. Iontophoresis enhanced the transport of MA and UR from anode to cathode, but this effect (electroosmosis) was marginal. The transport of TEA was significantly enhanced by anodal iontophoresis and the experimental enhancement factors were consistent with the Nernst-Planck theory predictions. Hindered transport was also observed and believed to be critical in transungual delivery. The barrier of the nail plates was stable over the time course of the study, and no significant electric field-induced alteration of the barrier was observed. The present results with hydrated nail plates are consistent with electrophoresis-dominant (the direct field effect) transungual iontophoretic transport of small ionic permeants with small contribution from electroosmosis. PMID:17683062

  13. Transungual iontophoretic transport of polar neutral and positively charged model permeants: effects of electrophoresis and electroosmosis.

    PubMed

    Hao, Jinsong; Li, S Kevin

    2008-02-01

    Transungual iontophoretic transport of model neutral permeants mannitol (MA), urea (UR), and positively charged permeant tetraethylammonium ion (TEA) across fully hydrated human nail plates at pH 7.4 were investigated in vitro. Four protocols were involved in the transport experiments with each protocol divided into stages including passive and iontophoresis transport of 0.1 and 0.3 mA. Water and permeant uptake experiments of nail clippings were also conducted to characterize the hydration and binding effects of the permeants to the nails. Iontophoresis enhanced the transport of MA and UR from anode to cathode, but this effect (electroosmosis) was marginal. The transport of TEA was significantly enhanced by anodal iontophoresis and the experimental enhancement factors were consistent with the Nernst-Planck theory predictions. Hindered transport was also observed and believed to be critical in transungual delivery. The barrier of the nail plates was stable over the time course of the study, and no significant electric field-induced alteration of the barrier was observed. The present results with hydrated nail plates are consistent with electrophoresis-dominant (the direct field effect) transungual iontophoretic transport of small ionic permeants with small contribution from electroosmosis.

  14. A new method of combination of electroosmosis, vacuum and surcharge preloading for soft ground improvement

    NASA Astrophysics Data System (ADS)

    Liu, Han-long; Cui, Yun-liang; Shen, Yang; Ding, Xuan-ming

    2014-08-01

    As a rapid and effective ground improvement method is urgently required for the booming land reclamation in China's coastal area, this study proposes a new combined method of electroosmosis, vacuum preloading and surcharge preloading. A new type of electrical prefabricated vertical drain (ePVD) and a new electroosmotic drainage system are suggested to allow the application of the new method. This combined method is then field-tested and compared with the conventional vacuum combined with surcharge preloading method. The monitoring and foundation test results show that the new method induces a settlement 20% larger than that of the conventional vacuum combined with surcharge preloading method in the same treatment period, and saves approximately half of the treatment time compared with the vacuum combined with surcharge preloading method according to the finite element prediction of the settlement. The proposed method also increases the vane shear strength of the soil significantly. The bearing capacity of the ground improved by use of the new proposed method raises 118%. In comparison, there is only a 75% rise when using the vacuum combined with surcharge preloading method during the same reinforcement period. All results indicate that the proposed combined method is effective and suitable for reinforcing the soft clay ground. Besides, the voltage applied between the anode and cathode increases exponentially versus treatment time when the output current of power supplies is kept constant. Most of the voltage potential in electroosmosis is lost at electrodes, leaving smaller than 50% of the voltage to be effectively transmitted into the soil.

  15. Method and apparatus for enhanced detection of toxic agents

    DOEpatents

    Greenbaum, Elias; Rodriguez, Jr., Miguel; Wu, Jie Jayne; Qi, Hairong

    2012-06-12

    A water quality analyzer for real-time detection according to the invention comprises a biased AC electro-osmosis (ACEO) cell for receiving a fluid to be analyzed having a plurality photosynthetic organisms therein, and concentrating the plurality photosynthetic organisms into at least one concentrated region. A photodetector is provided for obtaining a measured photosynthetic activity of the plurality of photosynthetic organisms in the concentrated region, wherein chemical, biological or radiological agents reduce a nominal photosynthetic activity of the photosynthetic organisms. An electronics package analyzes the measured photosynthetic activity to indicate a presence of the chemical, biological or radiological agents in the fluid.

  16. A Theoretical Analysis of the Influence of Electroosmosis on the Effective Ionic Mobility in Capillary Zone Electrophoresis

    ERIC Educational Resources Information Center

    Hijnen, Hens

    2009-01-01

    A theoretical description of the influence of electroosmosis on the effective mobility of simple ions in capillary zone electrophoresis is presented. The mathematical equations derived from the space-charge model contain the pK[subscript a] value and the density of the weak acid surface groups as parameters characterizing the capillary. It is…

  17. Contact-Free Templating of 3-D Colloidal Structures Using Spatially Nonuniform AC Electric Fields.

    PubMed

    Raveendran, Joshua; Wood, Jeffery A; Docoslis, Aristides

    2016-09-20

    The formation of ordered and regularly shaped structures of colloidal particles with the aid of spatially nonuniform electric fields is a modern research area of great interest. This work illustrates how alternating current (AC) electrokinetic effects (dielectrophoresis, electroosmosis) can serve as contact-free templates, inside which colloidal microspheres can assemble into a variety of shapes and sizes. We show how three-dimensional colloidal structures of square, circular, and diamond shape of many tens of micrometers in size can be reproducibly formed with a single set of quadrupolar microelectrodes. Numerical simulations performed help to explain the role of AC electroosmosis and AC dielectrophoresis on the shaping of these structures as a function of applied voltage and frequency. We also demonstrate how the templating repertoire is further enhanced with the simultaneous application of a second, individually controlled AC electric field, which enables a variety of asymmetric colloidal structures to be produced using the same set of quadrupolar microelectrodes. As the preservation of shape and size of such electric-field templated structures after medium evaporation still remains a big challenge, here we also report on a novel method that permits the stabilization and isolation of these particle assemblies through medium gelation and subsequent hydrogel removal with a UV/ozone treatment.

  18. AC Electric Field-Induced Trapping of Microparticles in Pinched Microconfinements.

    PubMed

    Dey, Ranabir; Shaik, Vaseem Akram; Chakraborty, Debapriya; Ghosal, Sandip; Chakraborty, Suman

    2015-06-01

    The trapping of charged microparticles under confinement in a converging-diverging microchannel, under a symmetric AC field of tunable frequency, is studied. We show that at low frequencies, the trapping characteristics stem from the competing effects of positive dielectrophoresis and the linear electrokinetic phenomena of electroosmosis and electrophoresis. It is found, somewhat unexpectedly, that electroosmosis and electrophoresis significantly affect the concentration profile of the trapped analyte, even for a symmetric AC field. However, at intermediate frequencies, the microparticle trapping mechanism is predominantly a consequence of positive dielectrophoresis. We substantiate our experimental results for the microparticle concentration distribution, along the converging-diverging microchannel, with a detailed theoretical analysis that takes into account all of the relevant frequency-dependent electrokinetic phenomena. This study should be useful in understanding the response of biological components such as cells to applied AC fields. Moreover, it will have potential applications in the design of efficient point-of-care diagnostic devices for detecting biomarkers and also possibly in some recent strategies in cancer therapy using AC fields. PMID:25954982

  19. Contact-Free Templating of 3-D Colloidal Structures Using Spatially Nonuniform AC Electric Fields.

    PubMed

    Raveendran, Joshua; Wood, Jeffery A; Docoslis, Aristides

    2016-09-20

    The formation of ordered and regularly shaped structures of colloidal particles with the aid of spatially nonuniform electric fields is a modern research area of great interest. This work illustrates how alternating current (AC) electrokinetic effects (dielectrophoresis, electroosmosis) can serve as contact-free templates, inside which colloidal microspheres can assemble into a variety of shapes and sizes. We show how three-dimensional colloidal structures of square, circular, and diamond shape of many tens of micrometers in size can be reproducibly formed with a single set of quadrupolar microelectrodes. Numerical simulations performed help to explain the role of AC electroosmosis and AC dielectrophoresis on the shaping of these structures as a function of applied voltage and frequency. We also demonstrate how the templating repertoire is further enhanced with the simultaneous application of a second, individually controlled AC electric field, which enables a variety of asymmetric colloidal structures to be produced using the same set of quadrupolar microelectrodes. As the preservation of shape and size of such electric-field templated structures after medium evaporation still remains a big challenge, here we also report on a novel method that permits the stabilization and isolation of these particle assemblies through medium gelation and subsequent hydrogel removal with a UV/ozone treatment. PMID:27541583

  20. Cytoplasmic electric fields and electroosmosis: possible solution for the paradoxes of the intracellular transport of biomolecules.

    PubMed

    Andreev, Victor P

    2013-01-01

    The objective of the paper is to show that electroosmotic flow might play an important role in the intracellular transport of biomolecules. The paper presents two mathematical models describing the role of electroosmosis in the transport of the negatively charged messenger proteins to the negatively charged nucleus and in the recovery of the fluorescence after photobleaching. The parameters of the models were derived from the extensive review of the literature data. Computer simulations were performed within the COMSOL 4.2a software environment. The first model demonstrated that the presence of electroosmosis might intensify the flux of messenger proteins to the nucleus and allow the efficient transport of the negatively charged phosphorylated messenger proteins against the electrostatic repulsion of the negatively charged nucleus. The second model revealed that the presence of the electroosmotic flow made the time of fluorescence recovery dependent on the position of the bleaching spot relative to cellular membrane. The magnitude of the electroosmotic flow effect was shown to be quite substantial, i.e. increasing the flux of the messengers onto the nucleus up to 4-fold relative to pure diffusion and resulting in the up to 3-fold change in the values of fluorescence recovery time, and therefore the apparent diffusion coefficient determined from the fluorescence recovery after photobleaching experiments. Based on the results of the modeling and on the universal nature of the electroosmotic flow, the potential wider implications of electroosmotic flow in the intracellular and extracellular biological processes are discussed. Both models are available for download at ModelDB. PMID:23613967

  1. Liquid crystal-enabled electro-osmosis through spatial charge separation in distorted regions as a novel mechanism of electrokinetics

    NASA Astrophysics Data System (ADS)

    Lazo, Israel; Peng, Chenhui; Xiang, Jie; Shiyanovskii, Sergij V.; Lavrentovich, Oleg D.

    2014-09-01

    Electrically controlled dynamics of fluids and particles at microscales is a fascinating area of research with applications ranging from microfluidics and sensing to sorting of biomolecules. The driving mechanisms are electric forces acting on spatially separated charges in an isotropic medium such as water. Here, we demonstrate that anisotropic conductivity of liquid crystals enables new mechanism of highly efficient electro-osmosis rooted in space charging of regions with distorted orientation. The electric field acts on these distortion-separated charges to induce liquid crystal-enabled electro-osmosis. Their velocities grow with the square of the field, which allows one to use an alternating current field to drive steady flows and to avoid electrode damage. Ionic currents in liquid crystals that have been traditionally considered as an undesirable feature in displays, offer a broad platform for versatile applications such as liquid crystal-enabled electrokinetics, micropumping and mixing.

  2. Liquid crystal-enabled electro-osmosis through spatial charge separation in distorted regions as a novel mechanism of electrokinetics

    PubMed Central

    Lazo, Israel; Peng, Chenhui; Xiang, Jie; Shiyanovskii, Sergij V.; Lavrentovich, Oleg D.

    2014-01-01

    Electrically controlled dynamics of fluids and particles at microscales is a fascinating area of research with applications ranging from microfluidics and sensing to sorting of biomolecules. The driving mechanisms are electric forces acting on spatially separated charges in an isotropic medium such as water. Here, we demonstrate that anisotropic conductivity of liquid crystals enables new mechanism of highly efficient electro-osmosis rooted in space charging of regions with distorted orientation. The electric field acts on these distortion-separated charges to induce liquid crystal-enabled electro-osmosis. Their velocities grow with the square of the field, which allows one to use an alternating current field to drive steady flows and to avoid electrode damage. Ionic currents in liquid crystals that have been traditionally considered as an undesirable feature in displays, offer a broad platform for versatile applications such as liquid crystal-enabled electrokinetics, micropumping and mixing. PMID:25255307

  3. ac electroosmotic pumping induced by noncontact external electrodes.

    PubMed

    Wang, Shau-Chun; Chen, Hsiao-Ping; Chang, Hsueh-Chia

    2007-01-01

    Electroosmotic (EO) pumps based on dc electroosmosis is plagued by bubble generation and other electrochemical reactions at the electrodes at voltages beyond 1 V for electrolytes. These disadvantages limit their throughput and offset their portability advantage over mechanical syringe or pneumatic pumps. ac electroosmotic pumps at high frequency (>100 kHz) circumvent the bubble problem by inducing polarization and slip velocity on embedded electrodes,1 but they require complex electrode designs to produce a net flow. We report a new high-throughput ac EO pump design based on induced-polarization on the entire channel surface instead of just on the electrodes. Like dc EO pumps, our pump electrodes are outside of the load section and form a cm-long pump unit consisting of three circular reservoirs (3 mm in diameter) connected by a 1x1 mm channel. The field-induced polarization can produce an effective Zeta potential exceeding 1 V and an ac slip velocity estimated as 1 mmsec or higher, both one order of magnitude higher than earlier dc and ac pumps, giving rise to a maximum throughput of 1 mulsec. Polarization over the entire channel surface, quadratic scaling with respect to the field and high voltage at high frequency without electrode bubble generation are the reasons why the current pump is superior to earlier dc and ac EO pumps. PMID:19693362

  4. Integrating biodegradation and electroosmosis for the enhanced removal of polycyclic aromatic hydrocarbons from creosote-polluted soils.

    PubMed

    Niqui-Arroyo, José-Luis; Ortega-Calvo, José-Julio

    2007-01-01

    This paper presents a hybrid technology of soil remediation based on the integration of biodegradation and electroosmosis. We employed soils with different texture (clay soil and loamy sand) containing a mixture of polycyclic aromatic hydrocarbons (PAH) present in creosote, and inoculation with a representative soil bacterium able to degrade fluorene, phenanthrene, fluoranthene, pyrene, anthracene, and benzo[a]pyrene. Two different modes of treatment were prospected: (i) inducing in soil the simultaneous occurrence of biodegradation and electroosmosis in the presence of a biodegradable surfactant, and (ii) treating the soils sequentially with electrokinetics and bioremediation. Losses of PAH due to simultaneous biodegradation and electroosmosis (induced by a continuous electric field) were significantly higher than in control cells that contained the surfactant but no biological activity or no current. The method was especially successful with loamy sand. For example, benzo[a]pyrene decreased its concentration by 50% after 7 d, whereas 22 and 17% of the compound had disappeared as a result of electrokinetic flushing and bioremediation alone, respectively. The use of periodical changes in polarity and current pulses increased by 16% in the removal of total PAH and in up to 30% of specific compounds, including benzo[a]pyrene. With the aim of reaching lower residual levels through bioremediation, an electrokinetic pretreatment was also evaluated as a way to mobilize the less bioaccessible fraction of PAH. Residual concentrations of total biodegradable PAH, remaining after bioremediation in soil slurries, were twofold lower in electrokinetically pretreated soils than in untreated soils. The results indicate that biodegradation and electroosmosis can be successfully integrated to promote the removal of PAH from soil.

  5. Simulation of an ac electro-osmotic pump with step microelectrodes

    NASA Astrophysics Data System (ADS)

    Kim, Byoung Jae; Lee, Seung-Hyun; Rezazadeh, Soghra; Sung, Hyung Jin

    2011-05-01

    Pumps with step microelectrodes subjected to an ac voltage are known to have faster pumping rates than those with planar asymmetric microelectrodes. The driving force for pumping in these systems is ac electro-osmosis. This paper aims to understand the flow behaviors of pumps with step microelectrodes by using a realistic model applicable to high external voltages. This model takes the steric effect due to the finite sizes of ions into account and copes with the exponential sensitivity of the counterion concentration to voltage. The effects on the pumping flow rate of varying the pump parameters were investigated. The geometrical parameters were optimized, and the effects of varying the ac frequency and amplitude were examined. The electrical potential of the fluid and the electrical charge at the electrode surface were solved simultaneously, and the Stokes equation was used to describe the fluid flow.

  6. 3D experimental investigation of the interplay between dielectrophoresis and induced-charge electroosmosis

    NASA Astrophysics Data System (ADS)

    Boymelgreen, Alicia; Zehavi, Matan; Yossifon, Gilad

    2014-11-01

    It is well-known that the advent non-linear electrokinetic flows, such as induced-charge electroosmosis, are strongly dependent on the frequency of the applied field. However, to date, there exists no unifying theory which can exactly predict both the strength and frequency dispersion of such electrokinetic flows. Using microPIV and temperature sensitive dyes we demonstrate the presence of a number of competing non-linear effects including dielectrophoresis, electrothermal flow and wall effects which compete with induced-charge electrokinetic flow, potentially causing a distortion of both the strength and frequency dispersion predicted for pure induced-charge effects. In terms of the wall effects, we investigate the differences between channels in which the walls are conducting (the field is perpendicular to the wall) and insulating (the field is parallel to the wall). This work is of both fundamental and practical importance and may be used to further refine non-linear electrokinetic theory and optimize the flow parameters of electroosmotic pumps and the mobility of electrokinetically driven micromotors or carriers in lab-on-a-chip analysis systems.

  7. dc step response of induced-charge electro-osmosis between parallel electrodes at large voltages

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2014-07-01

    Induced-charge electro-osmosis (ICEO) is important since it can be used for realizing high performance microfluidic devices. Here, we analyze the simplest problem of ion relaxation around a circular polarizable cylinder between parallel blocking electrodes in a closed cell by using a multiphysics coupled simulation technique. This technique is based on a combination of the finite-element method and finite-volume method for the Poisson-Nernst-Planck (PNP) equations having a flow term and the Stokes equation having an electric stress term. Through this analysis, we successfully demonstrate that on application of dc voltages, quadorapolar ICEO vortex flows grow during the charging time of the cylinder for both unbounded and bounded problems and decay during the charging time of the parallel electrodes only for the bounded problem using blocking electrodes. Further, by proposing a simple model that considers the two-dimensional (2D) PNP equations analytically, we successfully explain the step response time of the ICEO flow for the both unbounded and bounded problems. Furthermore, at low applied voltages, we find analytical formulations on steady diffused-ion problems and steady ICEO-flow problems and examine that our numerical results agree well with the analytical results. Moreover, by considering an ion-conserving condition with 2D Poisson-Boltzmann equations, we explain significant decrease of the maximum slip velocity at large applied voltages fairly well. We believe that our analysis will contribute greatly to the realistic designs of prospective high-performance microfluidic devices.

  8. Chaotic mixer using electro-osmosis at finite Péclet number

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2010-03-01

    Two pressure-driven streams of two miscible liquids can only mix by diffusion in microfluidic channels because of the low Reynolds number. We present an idea to generate mixing by “chaotic advection” in microscale geometries. That is, we consider using induced-charge electro-osmosis to generate a second flow and then modulate between the pressure-driven and induced-charge flows. By using the combined method consisting of the boundary element method, the Lagrangian particle tracking method, and the random-walk method, we analyze mixing efficiency, mixing time, and mixing length, with the effects of modulation frequency and molecular diffusivity, and compare our proposed mixer with other mixers. By this analysis, we find that chaotic mixing can be produced efficiently in a microfluidic channel by switching between pressure-driven and induced-charge flows in a wide range of Péclet number under the specific condition of Strouhal number. By using our proposed mixer, we can expect to realize efficient chaotic mixing with minimum voltage in an ordinary flow channel with a simple structure without an oblique electric field even at large Péclet number.

  9. A frequency-control particle separation device based on resultant effects of electroosmosis and dielectrophoresis

    NASA Astrophysics Data System (ADS)

    Lin, Shiang-Chi; Tung, Yi-Chung; Lin, Chih-Ting

    2016-08-01

    Particle separation plays an important role in microfluidic sample preparation for various biomedical applications. In this paper, we report a particle manipulation and separation scheme using a microfluidic device based on low-volume/low-voltage electrokinetic frequency modulation. Utilizing a circular micro-electrode array, both electroosmosis and dielectrophoresis can be contributed to manipulate particles in the device by controlling the frequency of applied sinusoidal travelling wave signals. Theoretical simulations based on finite-element methods are employed to establish fundamental understanding of the developed scheme. For experimental demonstration, polystyrene beads (6 μm in diameter) and human promyelocytic leukaemia cells (HL-60) are used to validate the frequency-modulation effect. Furthermore, different diameter polystyrene beads (6 μm and 10 μm in diameter) are mixed to show potentials of precise particle separations (˜90% efficiency) by the reported frequency-controlled electrokinetic device. The developed technique can be exploited as an actuation scheme and particle manipulation method for microfluidic sample preparations of low ionic concentration samples.

  10. dc Step response of induced-charge electro-osmosis between parallel electrodes at large voltages.

    PubMed

    Sugioka, Hideyuki

    2014-07-01

    Induced-charge electro-osmosis (ICEO) is important since it can be used for realizing high performance microfluidic devices. Here, we analyze the simplest problem of ion relaxation around a circular polarizable cylinder between parallel blocking electrodes in a closed cell by using a multiphysics coupled simulation technique. This technique is based on a combination of the finite-element method and finite-volume method for the Poisson-Nernst-Planck (PNP) equations having a flow term and the Stokes equation having an electric stress term. Through this analysis, we successfully demonstrate that on application of dc voltages, quadorapolar ICEO vortex flows grow during the charging time of the cylinder for both unbounded and bounded problems and decay during the charging time of the parallel electrodes only for the bounded problem using blocking electrodes. Further, by proposing a simple model that considers the two-dimensional (2D) PNP equations analytically, we successfully explain the step response time of the ICEO flow for the both unbounded and bounded problems. Furthermore, at low applied voltages, we find analytical formulations on steady diffused-ion problems and steady ICEO-flow problems and examine that our numerical results agree well with the analytical results. Moreover, by considering an ion-conserving condition with 2D Poisson-Boltzmann equations, we explain significant decrease of the maximum slip velocity at large applied voltages fairly well. We believe that our analysis will contribute greatly to the realistic designs of prospective high-performance microfluidic devices. PMID:25122369

  11. Electro-osmosis of non-Newtonian fluids in porous media using lattice Poisson-Boltzmann method.

    PubMed

    Chen, Simeng; He, Xinting; Bertola, Volfango; Wang, Moran

    2014-12-15

    Electro-osmosis in porous media has many important applications in various areas such as oil and gas exploitation and biomedical detection. Very often, fluids relevant to these applications are non-Newtonian because of the shear-rate dependent viscosity. The purpose of this study was to investigate the behaviors and physical mechanism of electro-osmosis of non-Newtonian fluids in porous media. Model porous microstructures (granular, fibrous, and network) were created by a random generation-growth method. The nonlinear governing equations of electro-kinetic transport for a power-law fluid were solved by the lattice Poisson-Boltzmann method (LPBM). The model results indicate that: (i) the electro-osmosis of non-Newtonian fluids exhibits distinct nonlinear behaviors compared to that of Newtonian fluids; (ii) when the bulk ion concentration or zeta potential is high enough, shear-thinning fluids exhibit higher electro-osmotic permeability, while shear-thickening fluids lead to the higher electro-osmotic permeability for very low bulk ion concentration or zeta potential; (iii) the effect of the porous medium structure depends significantly on the constitutive parameters: for fluids with large constitutive coefficients strongly dependent on the power-law index, the network structure shows the highest electro-osmotic permeability while the granular structure exhibits the lowest permeability on the entire range of power law indices considered; when the dependence of the constitutive coefficient on the power law index is weaker, different behaviors can be observed especially in case of strong shear thinning.

  12. Electro-osmosis of non-Newtonian fluids in porous media using lattice Poisson-Boltzmann method.

    PubMed

    Chen, Simeng; He, Xinting; Bertola, Volfango; Wang, Moran

    2014-12-15

    Electro-osmosis in porous media has many important applications in various areas such as oil and gas exploitation and biomedical detection. Very often, fluids relevant to these applications are non-Newtonian because of the shear-rate dependent viscosity. The purpose of this study was to investigate the behaviors and physical mechanism of electro-osmosis of non-Newtonian fluids in porous media. Model porous microstructures (granular, fibrous, and network) were created by a random generation-growth method. The nonlinear governing equations of electro-kinetic transport for a power-law fluid were solved by the lattice Poisson-Boltzmann method (LPBM). The model results indicate that: (i) the electro-osmosis of non-Newtonian fluids exhibits distinct nonlinear behaviors compared to that of Newtonian fluids; (ii) when the bulk ion concentration or zeta potential is high enough, shear-thinning fluids exhibit higher electro-osmotic permeability, while shear-thickening fluids lead to the higher electro-osmotic permeability for very low bulk ion concentration or zeta potential; (iii) the effect of the porous medium structure depends significantly on the constitutive parameters: for fluids with large constitutive coefficients strongly dependent on the power-law index, the network structure shows the highest electro-osmotic permeability while the granular structure exhibits the lowest permeability on the entire range of power law indices considered; when the dependence of the constitutive coefficient on the power law index is weaker, different behaviors can be observed especially in case of strong shear thinning. PMID:25278358

  13. A novel miniature dynamic microfluidic cell culture platform using electro-osmosis diode pumping

    PubMed Central

    Chang, Jen-Yung; Wang, Shuo; Allen, Jeffrey S.; Lee, Seong Hyuk; Chang, Suk Tai; Choi, Young-Ki; Friedrich, Craig; Choi, Chang Kyoung

    2014-01-01

    An electro-osmosis (EOS) diode pumping platform capable of culturing cells in fluidic cellular micro-environments particularly at low volume flow rates has been developed. Diode pumps have been shown to be a viable alternative to mechanically driven pumps. Typically electrokinetic micro-pumps were limited to low-concentration solutions (≤10 mM). In our approach, surface mount diodes were embedded along the sidewalls of a microchannel to rectify externally applied alternating current into pulsed direct current power across the diodes in order to generate EOS flows. This approach has for the first time generated flows at ultra-low flow rates (from 2.0 nl/s to 12.3 nl/s) in aqueous solutions with concentrations greater than 100 mM. The range of flow was generated by changing the electric field strength applied to the diodes from 0.5 Vpp/cm to 10 Vpp/cm. Embedding an additional diode on the upper surface of the enclosed microchannel increased flow rates further. We characterized the diode pump-driven fluidics in terms of intensities and frequencies of electric inputs, pH values of solutions, and solution types. As part of this study, we found that the growth of A549 human lung cancer cells was positively affected in the microfluidic diode pumping system. Though the chemical reaction compromised the fluidic control overtime, the system could be maintained fully functional over a long time if the solution was changed every hour. In conclusion, the advantage of miniature size and ability to accurately control fluids at ultra-low volume flow rates can make this diode pumping system attractive to lab-on-a-chip applications and biomedical engineering in vitro studies. PMID:25379101

  14. A novel miniature dynamic microfluidic cell culture platform using electro-osmosis diode pumping.

    PubMed

    Chang, Jen-Yung; Wang, Shuo; Allen, Jeffrey S; Lee, Seong Hyuk; Chang, Suk Tai; Choi, Young-Ki; Friedrich, Craig; Choi, Chang Kyoung

    2014-07-01

    An electro-osmosis (EOS) diode pumping platform capable of culturing cells in fluidic cellular micro-environments particularly at low volume flow rates has been developed. Diode pumps have been shown to be a viable alternative to mechanically driven pumps. Typically electrokinetic micro-pumps were limited to low-concentration solutions (≤10 mM). In our approach, surface mount diodes were embedded along the sidewalls of a microchannel to rectify externally applied alternating current into pulsed direct current power across the diodes in order to generate EOS flows. This approach has for the first time generated flows at ultra-low flow rates (from 2.0 nl/s to 12.3 nl/s) in aqueous solutions with concentrations greater than 100 mM. The range of flow was generated by changing the electric field strength applied to the diodes from 0.5 Vpp/cm to 10 Vpp/cm. Embedding an additional diode on the upper surface of the enclosed microchannel increased flow rates further. We characterized the diode pump-driven fluidics in terms of intensities and frequencies of electric inputs, pH values of solutions, and solution types. As part of this study, we found that the growth of A549 human lung cancer cells was positively affected in the microfluidic diode pumping system. Though the chemical reaction compromised the fluidic control overtime, the system could be maintained fully functional over a long time if the solution was changed every hour. In conclusion, the advantage of miniature size and ability to accurately control fluids at ultra-low volume flow rates can make this diode pumping system attractive to lab-on-a-chip applications and biomedical engineering in vitro studies.

  15. Electro-osmosis effectiveness in reducing tillage draft force and energy requirements

    SciTech Connect

    Larson, D.L.; Clyma, H.E.

    1995-09-01

    Tillage tests were conducted in a laboratory soil bin to quantify the draft force and tillage energy reductions obtained with electro-osmosis. Electrical parameters examined were voltage level and use of one or two anodes; the tillage tool served as the cathode. Tests were conducted in loam and clay loam soils at two moisture contents each at tillage speeds of 3.3 to 7.7 km/h. The application of an electrical potential reduced tillage draft forces up to 39% in a loam soil and up to 11% in a clay loam soil in soil bin tests. The greatest draft force reduction in the loam soil was obtained with a 40-V electrical input, one coulter as anode, soil moisture content of 17%, and tillage speed of 6.5km/h. The largest draft force reduction in the clay loam soil was obtained with a 45-V input at 3. 3 km/h. The largest draft force reduction was obtained in the wetter of the two test conditions in the loam soil, but in the drier clay loam soil test condition. Draft force decreased linearly with increasing voltage in all soil conditions; one anode yielded greater force reduction than two in nearly all tests. Draft force reduction was similar at all tillage speeds in the loam soil, but draft force reduction decreased with increasing tillage speed in clay loam tests. This research indicates application to a full-size tillage implement and in-field verification are merited to assess commercial potential of electro-osmotic tillage. 8 refs., 4 figs., 2 tabs.

  16. Electro-osmosis effectiveness in reducing tillage draft force and energy requirements. Final report

    SciTech Connect

    Larson, D.L.; Clyma, H.E.; Hoenig, S.; Cairo, G.; Jordan, K.A.; McFate, K.L.

    1993-03-01

    Tillage tests were conducted in a laboratory soil bin to quantify the draft force and tillage energy reductions obtained with electro-osmosis. Electrical parameters examined were voltage level and use of one or two anodes; the tillage tool served as the cathode. Tests were conducted in loam and clay loam soils at two moisture contents each at tillage speeds of 3.3 to 7.7 km/h. The application of an electrical potential reduced tillage draft force up to 39 percent in a loam soil and up to 11 percent in a clay loam soil in soil bin tests. The greatest draft force reduction in the loam soil was obtained with a 40 V electrical input, one coulter as anode, soil moisture content of 17 percent and tillage speed of 6.5 km/h. The largest draft force reduction in the clay loam soil was obtained with a 45 V input at 3.3 km/h. The largest draft force reduction was obtained in the wetter of two test conditions in the loam soil; but in the drier clay loam soil test condition, draft force decreased linearly with increasing voltage in all soil conditions; one anode yielded greater force reduction than two in nearly all tests. Draft force reduction was similar at all tillage speeds in the loam soil, but draft force reduction decreased with increasing tillage speed in clay loam tests. This research indicates application to a full size tillage implement and in-field verification are merited to assess commercial potential of electro-osmotic tillage.

  17. A novel miniature dynamic microfluidic cell culture platform using electro-osmosis diode pumping.

    PubMed

    Chang, Jen-Yung; Wang, Shuo; Allen, Jeffrey S; Lee, Seong Hyuk; Chang, Suk Tai; Choi, Young-Ki; Friedrich, Craig; Choi, Chang Kyoung

    2014-07-01

    An electro-osmosis (EOS) diode pumping platform capable of culturing cells in fluidic cellular micro-environments particularly at low volume flow rates has been developed. Diode pumps have been shown to be a viable alternative to mechanically driven pumps. Typically electrokinetic micro-pumps were limited to low-concentration solutions (≤10 mM). In our approach, surface mount diodes were embedded along the sidewalls of a microchannel to rectify externally applied alternating current into pulsed direct current power across the diodes in order to generate EOS flows. This approach has for the first time generated flows at ultra-low flow rates (from 2.0 nl/s to 12.3 nl/s) in aqueous solutions with concentrations greater than 100 mM. The range of flow was generated by changing the electric field strength applied to the diodes from 0.5 Vpp/cm to 10 Vpp/cm. Embedding an additional diode on the upper surface of the enclosed microchannel increased flow rates further. We characterized the diode pump-driven fluidics in terms of intensities and frequencies of electric inputs, pH values of solutions, and solution types. As part of this study, we found that the growth of A549 human lung cancer cells was positively affected in the microfluidic diode pumping system. Though the chemical reaction compromised the fluidic control overtime, the system could be maintained fully functional over a long time if the solution was changed every hour. In conclusion, the advantage of miniature size and ability to accurately control fluids at ultra-low volume flow rates can make this diode pumping system attractive to lab-on-a-chip applications and biomedical engineering in vitro studies. PMID:25379101

  18. Net Fluorescein Flux Across Corneal Endothelium Strongly Suggests Fluid Transport is due to Electro-osmosis.

    PubMed

    Sanchez, J M; Cacace, V; Kusnier, C F; Nelson, R; Rubashkin, A A; Iserovich, P; Fischbarg, J

    2016-08-01

    We have presented prior evidence suggesting that fluid transport results from electro-osmosis at the intercellular junctions of the corneal endothelium. Such phenomenon ought to drag other extracellular solutes. We have investigated this using fluorescein-Na2 as an extracellular marker. We measured unidirectional fluxes across layers of cultured human corneal endothelial (HCE) cells. SV-40-transformed HCE layers were grown to confluence on permeable membrane inserts. The medium was DMEM with high glucose and no phenol red. Fluorescein-labeled medium was placed either on the basolateral or the apical side of the inserts; the other side carried unlabeled medium. The inserts were held in a CO2 incubator for 1 h (at 37 °C), after which the entire volume of the unlabeled side was collected. After that, label was placed on the opposite side, and the corresponding paired sample was collected after another hour. Fluorescein counts were determined with a (Photon Technology) DeltaScan fluorometer (excitation 380 nm; emission 550 nm; 2 nm bwth). Samples were read for 60 s. The cells utilized are known to transport fluid from the basolateral to the apical side, just as they do in vivo in several species. We used 4 inserts for influx and efflux (total: 20 1-h periods). We found a net flux of fluorescein from the basolateral to the apical side. The flux ratio was 1.104 ± 0.056. That difference was statistically significant (p = 0.00006, t test, paired samples). The endothelium has a definite restriction at the junctions. Hence, an asymmetry in unidirectional fluxes cannot arise from osmosis, and can only point instead to paracellular solvent drag. We suggest, once more, that such drag is due to electro-osmotic coupling at the paracellular junctions. PMID:26989056

  19. Modulation of electroosmosis and flux through skin: effect of propylene glycol.

    PubMed

    Lee, Seung Yeon; Jeong, Na Young; Oh, Seaung Youl

    2014-04-01

    The effect of propylene glycol (PG) on transdermal flux under current was investigated using conventional in vitro iontophoresis methodology. The results were evaluated to explain how PG affects the electroosmotic volume flow (EVF) and electromigrational flux through skin. As a marker molecule for the direction and magnitude of EVF, a non-charged neutral molecule, acetaminophen (AAP), was used. At pH 7.4, the direction of EVF was from anode to cathode. During anodal and cathodal current application, PG decreased AAP flux and this decrease was proportional to the concentration of PG, indicating that the presence of PG in the medium decreased the EVF. This decrease is likely due to the decrease in dielectric constant of the medium and the increases in medium viscosity by the addition of PG. The increase in AAP solubility and the viscosity of the medium by PG may also contribute to the decrease in diffusional flux. The magnitude of EVF was estimated to be about 4.2 μl/cm(2 )h. The effect of PG on the flux of a positively charged drug, donepezil hydrochloride (DH), was further investigated using pH 4.6 phosphate buffer solution. The permselectivity of skin in this solution was also investigated and revealed that the isoelectric point of hairless mouse skin is higher than pH 4.6. Anodal delivery showed much higher flux than cathodal and passive flux, indicating that electromigration is playing the major role for DH flux. As the concentration of PG increased, anodal flux of DH decreased. The main reason for this decrease in electromigration is likely due to the increase in medium viscosity. These results and discussions clearly suggest that the incorporation of frequently used organic cosolvents and penetration enhancers into the iontophoretic formulation should be carefully chosen with a thorough investigation for their effect on flux. Overall, these results provided further mechanistic insights into the role of electroosmosis and electromigration in flux across skin

  20. Competition between Induced-Charge Electro-Osmosis and Electrothermal Effects at Low Frequencies around a Weakly Polarizable Microchannel Corner

    NASA Astrophysics Data System (ADS)

    Zehavi, Matan; Boymelgreen, Alicia; Yossifon, Gilad

    2016-04-01

    Sharp corners are an inherent component of most planar microfluidic systems, and thus their influence on flow within the microchannel is of significant interest. Here, we demonstrate that in electrokinetically driven devices, the presence of a sharp corner may result in localized vortices due to nonlinear induced-charge electro-osmosis (ICEO) and/or electrothermal forces. Application of an alternating-current electric field enables quantification of the nonlinear ICEO ejection-flow effect by isolating it from linear electro-osmotic background flow which is present under dc forcing. The hydrodynamic flow in the vicinity of a sharp channel corner is analyzed using experimental micro-particle-image-velocimetry and numerical simulations for different buffer concentrations, frequencies, and applied voltages. Divergence from the purely ICEO flow with increasing buffer conductivity is shown to be a result of increasing electrothermal effects due to Joule heating.

  1. Suppression of a Brownian noise in a hole-type sensor due to induced-charge electro-osmosis

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2016-03-01

    Noise reduction is essential for a single molecular sensor. Thus, we propose a novel noise reduction mechanism using a hydrodynamic force due to induced-charge electro-osmosis (ICEO) in a hole-type sensor and numerically examine the performance. By the boundary element method that considers both a Brownian motion and an ICEO flow of a polarizable particle, we find that the Brownian noise in a current signal is suppressed significantly in a converging channel because of the ICEO flow around the particle in the presence of an electric field. Further, we propose a simple model that explains a numerically obtained threshold voltage of the suppression of the Brownian noise due to ICEO. We believe that our findings contribute greatly to developments of a single molecular sensor.

  2. Synthesis and Characterization of a Hydrogel with Controllable Electroosmosis: A Potential Brain Tissue Surrogate for Electrokinetic Transport

    PubMed Central

    Faraji, Amir H.; Cui, Jonathan J.; Guy, Yifat; Li, Ling; Weber, Stephen G.

    2011-01-01

    Electroosmosis is the bulk fluid flow initiated by application of an electric field to an electrolyte solution in contact with immobile objects with a non-zero ζ-potential such as the surface of a porous medium. Electroosmosis may be used to assist analytical separations. Several gel-based systems with varying electroosmotic mobilities have been made in this context. A method was recently developed to determine the ζ-potential of organotypic hippocampal slice cultures (OHSC) as a representative model for normal brain tissue. The ζ-potential of the tissue is significant. However, determining the role of the ζ-potential in solute transport in tissue in an electric field is difficult because the tissue's ζ-potential cannot be altered. We hypothesized that mass transport properties, namely the ζ-potential and tortuosity, could be modulated by controlling the composition of a set of hydrogels. Thus, poly(acrylamide-co-acrylic acid) gels were prepared with three compositions (by monomer weight percent): acrylamide/acrylic acid 100/0, 90/10, and 75/25. The ζ-potentials of these gels at pH 7.4 are distinctly different, and in fact vary approximately linearly with the weight percent of acrylic acid. We discovered that the 25% acrylic acid gel is a respectable model for brain tissue, as its ζ-potential is comparable to the OHSC. This series of gels permits the experimental determination of the importance of electrokinetic properties in a particular experiment or protocol. Additionally, tortuosities were measured electrokinetically and by evaluating diffusion coefficients. Hydrogels with well-defined ζ-potential and tortuosity may find utility in biomaterials, analytical separations, and as a surrogate model for OHSC and living biological tissues. PMID:21905710

  3. 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.

  4. Multi-chamber electroosmosis using textile reinforced agar membranes--A promising concept for the future of hemodialysis.

    PubMed

    Kofler, Markus; Lenninger, Margit; Mayer, Gert; Neuwirt, Hannes; Grimm, Michael; Bechtold, Thomas

    2016-01-20

    Renal replacement therapy options are limited to hemodialysis and peritoneal dialysis (70% of US patients) or renal transplantation. Diffusion processes are the main physico-chemical principle behind hemodialysis. An alternative way to achieve liquid flow through membranes bases on the electroosmotic flow which is observed as electrokinetic phenomenon in porous membranes which bear surface charges. Agar consists of the non-ionic agarose and the negatively charged agaropectine thus an electroosmotic flux is observed in analytical electrophoresis. In this study the potential electroosmosis on textile reinforced agar membranes as separation method was investigated. Using a five-chamber electrolysis cell and an agar membrane/cellulose fabric composite an intensive electroosmotic flow of 1-2 ml cm(2) h(-1) at 100 mA cell current could be observed. The movement of cations in the negatively charged agar structure led to an intensive electroosmotic flux, which also transported uncharged molecules such as urea, glucose through the membrane. Separation of uncharged low molecular weight molecules is determined by the membrane characteristic. The transport of ions (K(+), PO4(3-), creatinine) and uncharged molecules (urea, glucose) in electroosmotic separation experiments was monitored using a pH 5.5 phosphate electrolyte with the aim to assess the overall transport processes in the electrochemical cell. The results demonstrate the potential of the method for filtration of biological fluids in the absence of external pressure or high shear rates.

  5. Electro-Osmosis and Water Uptake in Polymer Electrolytes in Equilibrium with Water Vapor at Low Temperatures

    SciTech Connect

    Gallagher, K. G.; Pivovar, B. S.; Fuller, T. F.

    2009-01-01

    Water uptake and electro-osmosis are investigated to improve the understanding and aid the modeling of water transport in proton-exchange membrane fuel cells (PEMFCs) below 0 C. Measurements of water sorption isotherms show a significant reduction in the water capacity of polymer electrolytes below 0 C. This reduced water content is attributed to the lower vapor pressure of ice compared to supercooled liquid water. At -25 C, 1100 equivalent weight Nafion in equilibrium with vapor over ice has 8 moles of water per sulfonic acid group. Measurements of the electro-osmotic drag coefficient for Nafion and both random and multiblock copolymer sulfonated poly(arylene ether sulfone) (BPSH) chemistries are reported for vapor equilibrated samples below 0 C. The electro-osmotic drag coefficient of BPSH chemistries is found to be {approx}0.4, and that of Nafion is {approx}1. No significant temperature effect on the drag coefficient is found. The implication of an electro-osmotic drag coefficient less than unity is discussed in terms of proton conduction mechanisms. Simulations of the ohmically limited current below 0 C show that a reduced water uptake below 0 C results in a significant decrease in PEMFC performance.

  6. Multi-chamber electroosmosis using textile reinforced agar membranes--A promising concept for the future of hemodialysis.

    PubMed

    Kofler, Markus; Lenninger, Margit; Mayer, Gert; Neuwirt, Hannes; Grimm, Michael; Bechtold, Thomas

    2016-01-20

    Renal replacement therapy options are limited to hemodialysis and peritoneal dialysis (70% of US patients) or renal transplantation. Diffusion processes are the main physico-chemical principle behind hemodialysis. An alternative way to achieve liquid flow through membranes bases on the electroosmotic flow which is observed as electrokinetic phenomenon in porous membranes which bear surface charges. Agar consists of the non-ionic agarose and the negatively charged agaropectine thus an electroosmotic flux is observed in analytical electrophoresis. In this study the potential electroosmosis on textile reinforced agar membranes as separation method was investigated. Using a five-chamber electrolysis cell and an agar membrane/cellulose fabric composite an intensive electroosmotic flow of 1-2 ml cm(2) h(-1) at 100 mA cell current could be observed. The movement of cations in the negatively charged agar structure led to an intensive electroosmotic flux, which also transported uncharged molecules such as urea, glucose through the membrane. Separation of uncharged low molecular weight molecules is determined by the membrane characteristic. The transport of ions (K(+), PO4(3-), creatinine) and uncharged molecules (urea, glucose) in electroosmotic separation experiments was monitored using a pH 5.5 phosphate electrolyte with the aim to assess the overall transport processes in the electrochemical cell. The results demonstrate the potential of the method for filtration of biological fluids in the absence of external pressure or high shear rates. PMID:26572331

  7. Location deterministic biosensing from quantum-dot-nanowire assemblies.

    PubMed

    Liu, Chao; Kim, Kwanoh; Fan, D L

    2014-08-25

    Semiconductor quantum dots (QDs) with high fluorescent brightness, stability, and tunable sizes, have received considerable interest for imaging, sensing, and delivery of biomolecules. In this research, we demonstrate location deterministic biochemical detection from arrays of QD-nanowire hybrid assemblies. QDs with diameters less than 10 nm are manipulated and precisely positioned on the tips of the assembled Gold (Au) nanowires. The manipulation mechanisms are quantitatively understood as the synergetic effects of dielectrophoretic (DEP) and alternating current electroosmosis (ACEO) due to AC electric fields. The QD-nanowire hybrid sensors operate uniquely by concentrating bioanalytes to QDs on the tips of nanowires before detection, offering much enhanced efficiency and sensitivity, in addition to the position-predictable rationality. This research could result in advances in QD-based biomedical detection and inspires an innovative approach for fabricating various QD-based nanodevices. PMID:25316926

  8. Location deterministic biosensing from quantum-dot-nanowire assemblies

    SciTech Connect

    Liu, Chao; Kim, Kwanoh; Fan, D. L.

    2014-08-25

    Semiconductor quantum dots (QDs) with high fluorescent brightness, stability, and tunable sizes, have received considerable interest for imaging, sensing, and delivery of biomolecules. In this research, we demonstrate location deterministic biochemical detection from arrays of QD-nanowire hybrid assemblies. QDs with diameters less than 10 nm are manipulated and precisely positioned on the tips of the assembled Gold (Au) nanowires. The manipulation mechanisms are quantitatively understood as the synergetic effects of dielectrophoretic (DEP) and alternating current electroosmosis (ACEO) due to AC electric fields. The QD-nanowire hybrid sensors operate uniquely by concentrating bioanalytes to QDs on the tips of nanowires before detection, offering much enhanced efficiency and sensitivity, in addition to the position-predictable rationality. This research could result in advances in QD-based biomedical detection and inspires an innovative approach for fabricating various QD-based nanodevices.

  9. AC Electrokinetic Cell Separation on a Microfluidic Device

    NASA Astrophysics Data System (ADS)

    Gagnon, Zachary; Chang, Hsueh-Chia

    2009-03-01

    Rapid cell separation and collection is demonstrated through the integration of electrokinetic pumps, dielectrophoretic (DEP) traps and field driven valves into a well designed microfluidic channel loop. We present the ground-up design and analysis of this fully functional microfluidic device for the rapid separation and collection of live and dead yeast cells and malaria red blood cells (RBCs) at low concentrations. DEP cell sorting and concentration schemes are based on the exploitation of cell specific DEP crossover frequencies (cof's). A rigorous DEP study of yeast and RBCs is presented and used to determine optimal conditions for cell separation. By utilizing a glutaraldehyde crosslinking cell fixation reaction that is sensitive to cell membrane protein concentration, we demonstrate the ability to further amplify these differences between healthy and unhealthy cells as well as stabilize their DEP cof's. Pumping is achieved with a new type of electrokinetic flow, AC electrothermal electro-osmosis (ETEO) and is shown to scale inversely with the field induced debye length and drive fluid velocities in excess of 6 mm/sec. The well characterized electrokinetic phenomena are integrated into a microchannel loop with a specifically designed electrode field penetration length for low concentration cell separation and concentration.

  10. 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.

  11. The Role of the Tight Junction in Paracellular Fluid Transport across Corneal Endothelium. Electro-osmosis as a Driving Force.

    PubMed

    Fischbarg, J; Diecke, F P J; Iserovich, P; Rubashkin, A

    2006-03-01

    The mechanism of epithelial fluid transport is controversial and remains unsolved. Experimental difficulties pose obstacles for work on a complex phenomenon in delicate tissues. However, the corneal endothelium is a relatively simple system to which powerful experimental tools can be applied. In recent years our laboratory has developed experimental evidence and theoretical insights that illuminate the mechanism of fluid transport across this leaky epithelium. Our evidence points to fluid being transported via the paracellular route by a mechanism requiring junctional integrity, which we attribute to electro-osmotic coupling at the junctions. Fluid movements can be produced by electrical currents. The direction of the movement can be reversed by current reversal or by changing junctional electrical charges by polylysine. Aquaporin 1 (AQP1) is the only AQP present in these cells, and its deletion in AQP1 null mice significantly affects cell osmotic permeability but not fluid transport, which militates against the presence of sizable water movements across the cell. By contrast, AQP1 null mice cells have reduced regulatory volume decrease (only 60% of control), which suggests a possible involvement of AQP1 in either the function or the expression of volume-sensitive membrane channels/transporters. A mathematical model of corneal endothelium predicts experimental results only when based on paracellular electro-osmosis, and not when transcellular local osmosis is assumed instead. Our experimental findings in corneal endothelium have allowed us to develop a novel paradigm for this preparation that includes: (1) paracellular fluid flow; (2) a crucial role for the junctions; (3) hypotonicity of the primary secretion; (4) an AQP role in regulation and not as a significant water pathway. These elements are remarkably similar to those proposed by the Hill laboratory for leaky epithelia. PMID:16868674

  12. A low sample volume particle separation device with electrokinetic pumping based on circular travelling-wave electroosmosis.

    PubMed

    Lin, Shiang-Chi; Lu, Jau-Ching; Sung, Yu-Lung; Lin, Chih-Ting; Tung, Yi-Chung

    2013-08-01

    Particle separation is a crucial step in sample preparation processes. The preparation of low volume samples is especially important for clinical diagnosis and chemical analysis. The advantages of microfluidic techniques have lead them to become potential candidates for particle separation. However, existing microfluidic devices require external pumping sources and extensive geometric patterns to attain high separation efficiency, which is disadvantageous when handling low volume samples. This paper presents a low sample volume particle separation microfluidic device with low voltage electrokinetic pumping based on circular travelling-wave electroosmosis (TWEO). Computational numerical software was utilized to simulate two electrokinetic mechanisms: circular TWEO and dielectrophoresis (DEP). The circular TWEO shear flow generates a velocity gradient in the radial direction which causes a shear stress-induced force to drag particles into the center region of the device. In contrast, the non-parallel electrodes induce negative DEP forces which push polystyrene beads towards the peripheral regions; the magnitude of the DEP forces are dependent on the sizes of the polystyrene beads. We used particles of various sizes to experimentally prove the concept of particle separation. Our experiments show that 15 μm beads are dragged into the center region due to the shear stress-induced force, and 1 μm beads move towards the outer region because of the large negative DEP force. The results show a separation purity of 94.4% and 80.0% for 15 μm and 1 μm beads respectively. We further demonstrated particle isolation from a sample of containing a small proportion of 6 μm beads mixed with 1 μm beads at a concentration ratio of 1 : 300. Therefore, the innovative device developed in this paper provides a promising solution to allow particle separation in sample volumes as low as 50 nL. PMID:23753015

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Effect of Combination of Low-Frequency Sonophoresis or Electroporation with Iontophoresis on the Mannitol Flux or Electroosmosis through Excised Skin.

    PubMed

    Tokumoto, Seiji; Higo, Naruhito; Todo, Hiroaki; Sugibayashi, Kenji

    2016-01-01

    In vitro permeation studies of mannitol were conducted across excised hairless mouse skin to determine and compare the enhancing effect of electroporation (EP) or sonophoresis (SP) combined with iontophoresis (IP) on the electroosmotic flow, and to analyze the enhancement mechanism of these combined methods. Mannitol flux was utilized as an index for the electroosmotic flow due to its low molecular weight and no electrorepulsion effect. The combination of SP and IP (SP/IP) resulted in an apparent increase of electroosmotic flow (no effect was sometimes observed by SP/IP), while that of EP and IP (EP/IP) had no synergistic enhancing effect on the electroosmosis. Next, the combined effect of tape-stripping (TS) and IP (TS/IP) was examined in a similar manner to clarify the difference between the SP/IP and EP/IP effects on electroosmosis. When the TS number increased from 0 to 3, the electroosmotic flow increased with the TS number. However, no further increase was observed when the TS number became more than 3, and the flow started to decrease when the TS number became 5. The electric charge of the skin surface was then measured after SP or TS application. When SP was applied, the skin surface charge became much more negative and the electroosmotic flow by SP/IP was markedly increased. Thus, an increase in the electroosmotic flow across the skin during IP application can be obtained not by EP and TS, but by SP. The combined use of SP and IP is a promising means for the enhanced skin delivery of non-electrolyte drugs. PMID:27374295

  19. ac bidirectional motor controller

    NASA Technical Reports Server (NTRS)

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  20. 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.

  1. Resonant dielectrophoresis and electrohydrodynamics for high-sensitivity impedance detection of whole-cell bacteria.

    PubMed

    Couniot, Numa; Francis, Laurent A; Flandre, Denis

    2015-08-01

    We present the co-integration of CMOS-compatible Al/Al2O3 interdigitated microelectrodes (IDEs) with an electrokinetic-driven macroelectrode for sensitive detection of whole-cell bacteria in a microfluidic channel. Two frequency ranges applied to the macroelectrode were identified to notably increase the bacterial coverage of the impedimetric sensor per unit time. Around 10 kHz, the bacterial cells were directed towards the IDE center thanks to AC electroosmosis (AC-EO) and the sensor capacitance linearly increased, achieving a limit of detection (LoD) of 3.5 × 10(5) CFU mL(-1) after an incubation time of 20 min with Staphylococcus epidermidis. At 63 MHz precisely, a resonance effect due to the device was found to dramatically increase the trapping of S. epidermidis on the sensor periphery, due to the combined actions of short-range contactless dielectrophoresis (cDEP) and long-range Joule heating electrothermal (J-ET) flow. Thanks to a flow-based method, the bacterial cells were redirected towards the sensor center and an LoD of 10(5) CFU mL(-1) was achieved within 20 min of incubation, which is almost two orders of magnitude better than the impedimetric sensor alone. Analytical models and 2D simulations using the Maxwell stress tensor (MST) provide a comprehensive analysis of the experimental results, especially about the spectral balance between cDEP, AC-EO and J-ET accounting for the 33-nm thick insulating layer atop the electrodes. Electrode CMOS compatibility confers portability, miniaturization and affordability capabilities for building point-of-care (PoC) diagnostic tests in a lab-on-a-chip (LoC).

  2. Resonant dielectrophoresis and electrohydrodynamics for high-sensitivity impedance detection of whole-cell bacteria.

    PubMed

    Couniot, Numa; Francis, Laurent A; Flandre, Denis

    2015-08-01

    We present the co-integration of CMOS-compatible Al/Al2O3 interdigitated microelectrodes (IDEs) with an electrokinetic-driven macroelectrode for sensitive detection of whole-cell bacteria in a microfluidic channel. Two frequency ranges applied to the macroelectrode were identified to notably increase the bacterial coverage of the impedimetric sensor per unit time. Around 10 kHz, the bacterial cells were directed towards the IDE center thanks to AC electroosmosis (AC-EO) and the sensor capacitance linearly increased, achieving a limit of detection (LoD) of 3.5 × 10(5) CFU mL(-1) after an incubation time of 20 min with Staphylococcus epidermidis. At 63 MHz precisely, a resonance effect due to the device was found to dramatically increase the trapping of S. epidermidis on the sensor periphery, due to the combined actions of short-range contactless dielectrophoresis (cDEP) and long-range Joule heating electrothermal (J-ET) flow. Thanks to a flow-based method, the bacterial cells were redirected towards the sensor center and an LoD of 10(5) CFU mL(-1) was achieved within 20 min of incubation, which is almost two orders of magnitude better than the impedimetric sensor alone. Analytical models and 2D simulations using the Maxwell stress tensor (MST) provide a comprehensive analysis of the experimental results, especially about the spectral balance between cDEP, AC-EO and J-ET accounting for the 33-nm thick insulating layer atop the electrodes. Electrode CMOS compatibility confers portability, miniaturization and affordability capabilities for building point-of-care (PoC) diagnostic tests in a lab-on-a-chip (LoC). PMID:26120099

  3. 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.

  4. 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.

  5. AC resistance measuring instrument

    DOEpatents

    Hof, P.J.

    1983-10-04

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

  6. AC Resistance measuring instrument

    DOEpatents

    Hof, Peter J.

    1983-01-01

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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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)

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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/

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  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. 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.

  9. 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.

  10. 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.

  11. 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.

  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. 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...

  16. 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'…

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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....

  2. 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....

  3. 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....

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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).

  9. 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

  10. 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.)

  11. 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-...

  12. 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.

  13. 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.

  14. 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.

  15. Electro-osmosis in nematic liquid crystals.

    PubMed

    Tovkach, O M; Calderer, M Carme; Golovaty, Dmitry; Lavrentovich, Oleg; Walkington, Noel J

    2016-07-01

    We derive a mathematical model of a nematic electrolyte based on a variational formulation of nematodynamics. We verify the model by comparing its predictions to the results of the experiments on the substrate-controlled liquid-crystal-enabled electrokinetics. In the experiments, a nematic liquid crystal confined to a thin planar cell with surface-patterned anchoring conditions exhibits electro-osmotic flows along the "guiding rails" imposed by the spatially varying director. Extending our previous work, we consider a general setup which incorporates dielectric anisotropy of the liquid-crystalline matrix and the full set of nematic viscosities.

  16. Chaotic induced-charge electro-osmosis.

    PubMed

    Davidson, Scott M; Andersen, Mathias B; Mani, Ali

    2014-03-28

    We present direct numerical simulations of the coupled Poisson-Nernst-Planck and Navier-Stokes equations for an electrolyte around a polarizable cylinder subject to an external electric field. For high fields, a novel chaotic flow phenomenon is discovered. Our calculations indicate significant improvement in the prediction of the mean flow relative to standard asymptotic models. These results open possibilities for chaos-enhanced mixing in microdevices and provide insight into barriers to efficient electrokinetic micropumps with broad applications in electrochemical and lab-on-a-chip systems. PMID:24724683

  17. Compensating for Electro-Osmosis in Electrophoresis

    NASA Technical Reports Server (NTRS)

    Rhodes, Percy H.; Snyder, Robert S.

    1987-01-01

    Simple mechanical adjustment eliminates transverse velocity component. New apparatus for moving-wall electrophoresis increases degree of collimation of chemical species in sample stream. Electrophoresis chamber set at slight angle in horizontal plane to adjust angle between solution flow and wall motion. Component of velocity created cancels electro-osmotic effect.

  18. Electro-osmosis in nematic liquid crystals

    NASA Astrophysics Data System (ADS)

    Tovkach, O. M.; Calderer, M. Carme; Golovaty, Dmitry; Lavrentovich, Oleg; Walkington, Noel J.

    2016-07-01

    We derive a mathematical model of a nematic electrolyte based on a variational formulation of nematodynamics. We verify the model by comparing its predictions to the results of the experiments on the substrate-controlled liquid-crystal-enabled electrokinetics. In the experiments, a nematic liquid crystal confined to a thin planar cell with surface-patterned anchoring conditions exhibits electro-osmotic flows along the "guiding rails" imposed by the spatially varying director. Extending our previous work, we consider a general setup which incorporates dielectric anisotropy of the liquid-crystalline matrix and the full set of nematic viscosities.

  19. Electro-osmosis in nematic liquid crystals.

    PubMed

    Tovkach, O M; Calderer, M Carme; Golovaty, Dmitry; Lavrentovich, Oleg; Walkington, Noel J

    2016-07-01

    We derive a mathematical model of a nematic electrolyte based on a variational formulation of nematodynamics. We verify the model by comparing its predictions to the results of the experiments on the substrate-controlled liquid-crystal-enabled electrokinetics. In the experiments, a nematic liquid crystal confined to a thin planar cell with surface-patterned anchoring conditions exhibits electro-osmotic flows along the "guiding rails" imposed by the spatially varying director. Extending our previous work, we consider a general setup which incorporates dielectric anisotropy of the liquid-crystalline matrix and the full set of nematic viscosities. PMID:27575193

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.}

  6. 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

  7. 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.

  8. AC electric field for rapid assembly of nanostructured polyaniline onto microsized gap for sensor devices.

    PubMed

    La Ferrara, Vera; Rametta, Gabriella; De Maria, Antonella

    2015-07-01

    Interconnected network of nanostructured polyaniline (PANI) is giving strong potential for enhancing device performances than bulk PANI counterparts. For nanostructured device processing, the main challenge is to get prototypes on large area by requiring precision, low cost and high rate assembly. Among processes meeting these requests, the alternate current electric fields are often used for nanostructure assembling. For the first time, we show the assembly of nanostructured PANI onto large electrode gaps (30-60 μm width) by applying alternate current electric fields, at low frequencies, to PANI particles dispersed in acetonitrile (ACN). An important advantage is the short assembly time, limited to 5-10 s, although electrode gaps are microsized. That encouraging result is due to a combination of forces, such as dielectrophoresis (DEP), induced-charge electrokinetic (ICEK) flow and alternate current electroosmotic (ACEO) flow, which speed up the assembly process when low frequencies and large electrode gaps are used. The main achievement of the present study is the development of ammonia sensors created by direct assembling of nanostructured PANI onto electrodes. Sensors exhibit high sensitivity to low gas concentrations as well as excellent reversibility at room temperature, even after storage in air.

  9. 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.

  10. 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.

  11. 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.

  12. [Intestinal occlusion and abdominal compartment syndrome (ACS)].

    PubMed

    Stagnitti, Franco

    2009-01-01

    Intestinal occlusion is defined as an independent predictive factor of intra-abdominal hypertension (IAH) which represents an independent predictor of mortality. Baggot in 1951 classified patients operated with intestinal occlusion as being at risk for IAH ("abdominal blow-out"), recommending them for open abdomen surgery proposed by Ogilvie. Abdominal surgery provokes IAH in 44.7% of cases with mortality which, in emergency, triples with respect to elective surgery (21.9% vs 6.8%). In particular, IAH is present in 61.2% of ileus and bowel distension and is responsible for 52% of mortality (54.8% in cases with intra-abdominal infection). These patients present with an increasing intra-abdominal pressure (IAP) which, over 20-25 mmHg, triggers an Abdominal Compartment Syndrome (ACS) with altered functions in some organs arriving at Multiple Organ Dysfunction Syndrome (MODS). The intestine normally covers 58% of abdominal volume but when there is ileus distension, intestinal pneumatosis develops (third space) which can occupy up to 90% of the entire cavity. At this moment, Gastro Intestinal Failure (GIF) can appear, which is a specific independent risk factor of mortality, motor of "Organ Failure". The pathophysiological evolution has many factors in 45% of cases: intestinal pneumatosis is associated with mucosal and serous edema, capillary leakage with an increase in extra-cellular volume and peritoneal fluid collections (fourth space). The successive loss of the mucous barrier permits a bacterial translocation which includes bacteria, toxins, pro-inflammatory factors and oxygen free radicals facilitating the passage from an intra-abdominal to inter-systemic vicious cyrcle. IAH provokes the raising of the diaphragm, and vascular and visceral compressions which induce hypertension in the various spaces with compartmental characteristics. These trigger hypertension in the renal, hepatic, pelvic, thoracic, cardiac, intracranial, orbital and lower extremity areas, giving

  13. Induced- and alternating-current electro-osmotic control of the diffusion layer growth in a microchannel-membrane interface device

    NASA Astrophysics Data System (ADS)

    Park, Sinwook; Yossifon, Gilad

    2014-11-01

    The passage of an electric current through an ionic permselective medium under an applied electric field is characterized by the formation of ionic concentration gradients, which result in regions of depleted and enriched ionic concentration at opposite ends of the medium. Induced-current electro-osmosis (ICEO) and alternating-current-electro-osmosis (ACEO) are shown to control the growth of the diffusion layer (DL) which, in turn, controls the diffusion limited ion transport through the microchannel-membrane system. We fabricated and tested devices made of a Nafion membrane connecting two opposite PDMS microchannels. An interdigitated electrode array was embedded within the microchannel with various distances from the microchannel-membrane interface. The induced ICEO (floating electrodes) / ACEO (active electrodes) vortices formed at the electrode array stir the fluid and thereby suppress the growth of the DL. The intensity of the ACEO vortices is controlled by either varying the voltage amplitude or the frequency, each having its own unique effect. Enhancement of the limiting current by on-demand control of the diffusion length is of importance in on-chip electro-dialysis, desalination and preconcentration of analytes.

  14. Evidence on the Molecular Basis of the Ac/ac Adaptive Cyanogenesis Polymorphism in White Clover (Trifolium repens L.)

    PubMed Central

    Olsen, Kenneth M.; Hsu, Shih-Chung; Small, Linda L.

    2008-01-01

    White clover is polymorphic for cyanogenesis, with both cyanogenic and acyanogenic plants occurring in nature. This chemical defense polymorphism is one of the longest-studied and best-documented examples of an adaptive polymorphism in plants. It is controlled by two independently segregating genes: Ac/ac controls the presence/absence of cyanogenic glucosides; and Li/li controls the presence/absence of their hydrolyzing enzyme, linamarase. Whereas Li is well characterized at the molecular level, Ac has remained unidentified. Here we report evidence that Ac corresponds to a gene encoding a cytochrome P450 of the CYP79D protein subfamily (CYP79D15), and we describe the apparent molecular basis of the Ac/ac polymorphism. CYP79D orthologs catalyze the first step in cyanogenic glucoside biosynthesis in other cyanogenic plant species. In white clover, Southern hybridizations indicate that CYP79D15 occurs as a single-copy gene in cyanogenic plants but is absent from the genomes of ac plants. Gene-expression analyses by RT–PCR corroborate this finding. This apparent molecular basis of the Ac/ac polymorphism parallels our previous findings for the Li/li polymorphism, which also arises through the presence/absence of a single-copy gene. The nature of these polymorphisms may reflect white clover's evolutionary origin as an allotetraploid derived from cyanogenic and acyanogenic diploid progenitors. PMID:18458107

  15. Advanced ac powertrain for electric vehicles

    SciTech Connect

    Slicker, J.M.; Kalns, L.

    1985-01-01

    The design of an ac propulsion system for an electric vehicle includes a three-phase induction motor, transistorized PWM inverter/battery charger, microprocessor-based controller, and two-speed automatic transaxle. This system was built and installed in a Mercury Lynx test bed vehicle as part of a Department of Energy propulsion system development program. An integral part of the inverter is a 4-kw battery charger which utilizes one of the bridge transistors. The overall inverter strategy for this configuration is discussed. The function of the microprocessor-based controller is described. Typical test results of the total vehicle and each of its major components are given, including system efficiencies and test track performance results.

  16. Fuzzy efficiency optimization of AC induction motors

    NASA Technical Reports Server (NTRS)

    Jani, Yashvant; Sousa, Gilberto; Turner, Wayne; Spiegel, Ron; Chappell, Jeff

    1993-01-01

    This paper describes the early states of work to implement a fuzzy logic controller to optimize the efficiency of AC induction motor/adjustable speed drive (ASD) systems running at less than optimal speed and torque conditions. In this paper, the process by which the membership functions of the controller were tuned is discussed and a controller which operates on frequency as well as voltage is proposed. The membership functions for this dual-variable controller are sketched. Additional topics include an approach for fuzzy logic to motor current control which can be used with vector-controlled drives. Incorporation of a fuzzy controller as an application-specific integrated circuit (ASIC) microchip is planned.

  17. AcMNPV ac143 (odv-e18) is essential for mediating budded virus production and is the 30th baculovirus core gene.

    PubMed

    McCarthy, Christina B; Theilmann, David A

    2008-05-25

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac143 (odv-e18) is a late gene that encodes for a predicted 9.6 kDa structural protein that locates to the occlusion derived viral envelope and viral induced intranuclear microvesicles [Braunagel, S.C., He, H., Ramamurthy, P., and Summers, M.D. (1996). Transcription, translation, and cellular localization of three Autographa californica nuclear polyhedrosis virus structural proteins: ODV-E18, ODV-E35, and ODV-EC27. Virology 222, 100-114.]. In this study we demonstrate that ac143 is actually a previously unrecognized core gene and that it is essential for mediating budded virus production. To examine the role of ac143 in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac143 knockout (KO) virus (AcBAC(ac142)(REP-ac143KO)). Fluorescence and light microscopy showed that infection by AcBAC(ac142)(REP-ac143KO) is limited to a single cell and titration assays confirmed that AcBAC(ac142)(REP-ac143KO) was unable to produce budded virus (BV). Progression to very late phases of the viral infection was evidenced by the development of occlusion bodies in the nuclei of transfected cells. This correlated with the fact that viral DNA replication was unaffected in AcBAC(ac142)(REP-ac143KO) transfected cells. The entire ac143 promoter, which includes three late promoter motifs, is contained within the ac142 open reading frame. Different deletion mutants of this region showed that the integrity of the ac142-ac143 core gene cluster was required for the bacmids to display wild-type patterns of viral replication, BV production and RNA transcription.

  18. AcMNPV ac143 (odv-e18) is essential for mediating budded virus production and is the 30th baculovirus core gene

    SciTech Connect

    McCarthy, Christina B.; Theilmann, David A.

    2008-05-25

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac143 (odv-e18) is a late gene that encodes for a predicted 9.6 kDa structural protein that locates to the occlusion derived viral envelope and viral induced intranuclear microvesicles [Braunagel, S.C., He, H., Ramamurthy, P., and Summers, M.D. (1996). Transcription, translation, and cellular localization of three Autographa californica nuclear polyhedrosis virus structural proteins: ODV-E18, ODV-E35, and ODV-EC27. Virology 222, 100-114.]. In this study we demonstrate that ac143 is actually a previously unrecognized core gene and that it is essential for mediating budded virus production. To examine the role of ac143 in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac143 knockout (KO) virus (AcBAC{sup ac142REP-ac143KO}). Fluorescence and light microscopy showed that infection by AcBAC{sup ac142REP-ac143KO} is limited to a single cell and titration assays confirmed that AcBAC{sup ac142REP-ac143KO} was unable to produce budded virus (BV). Progression to very late phases of the viral infection was evidenced by the development of occlusion bodies in the nuclei of transfected cells. This correlated with the fact that viral DNA replication was unaffected in AcBAC{sup ac142REP-ac143KO} transfected cells. The entire ac143 promoter, which includes three late promoter motifs, is contained within the ac142 open reading frame. Different deletion mutants of this region showed that the integrity of the ac142-ac143 core gene cluster was required for the bacmids to display wild-type patterns of viral replication, BV production and RNA transcription.

  19. 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.

  20. Wind-powered asynchronous AC/DC/AC converter system. [for electric power supply regulation

    NASA Technical Reports Server (NTRS)

    Reitan, D. K.

    1973-01-01

    Two asynchronous ac/dc/ac systems are modelled that utilize wind power to drive a variable or constant hertz alternator. The first system employs a high power 60-hertz inverter tie to the large backup supply of the power company to either supplement them from wind energy, storage, or from a combination of both at a preset desired current; rectifier and inverter are identical and operate in either mode depending on the silicon control rectifier firing angle. The second system employs the same rectification but from a 60-hertz alternator arrangement; it provides mainly dc output, some sinusoidal 60-hertz from the wind bus and some high harmonic content 60-hertz from an 800-watt inverter.

  1. Operation of AC Adapters Visualized Using Light-Emitting Diodes

    ERIC Educational Resources Information Center

    Regester, Jeffrey

    2016-01-01

    A bridge rectifier is a diamond-shaped configuration of diodes that serves to convert alternating current(AC) into direct current (DC). In our world of AC outlets and DC electronics, they are ubiquitous. Of course, most bridge rectifiers are built with regular diodes, not the light-emitting variety, because LEDs have a number of disadvantages. For…

  2. 24 CFR Appendices A-C to Subtitle A - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false A Appendices A-C to Subtitle A Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development Appendices A-C to Subtitle A...

  3. 24 CFR Appendices A-C to Subtitle A - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false A Appendices A-C to Subtitle A Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development Appendices A-C to Subtitle A...

  4. 24 CFR Appendices A-C to Subtitle A - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false A Appendices A-C to Subtitle A Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development Appendices A-C to Subtitle A...

  5. 24 CFR Appendixes A-C to Subtitle A - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false A Appendixes A-C to Subtitle A Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development Appendixes A-C to Subtitle A...

  6. 40 CFR Appendixes A-C to Part 403 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true A Appendixes A-C to Part 403 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRE-TREAT-MENT REGULATIONS FOR EXIST-ING AND NEW SOURCES OF POLLUTION Appendixes A-C to Part 403...

  7. 40 CFR Appendixes A-C to Part 403 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true A Appendixes A-C to Part 403 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRE-TREAT-MENT REGULATIONS FOR EXIST-ING AND NEW SOURCES OF POLLUTION Appendixes A-C to Part 403...

  8. Electrostatic coalescence system with independent AC and DC hydrophilic electrodes

    DOEpatents

    Hovarongkura, A. David; Henry, Jr., Joseph D.

    1981-01-01

    An improved electrostatic coalescence system is provided in which independent AC and DC hydrophilic electrodes are employed to provide more complete dehydration of an oil emulsion. The AC field is produced between an AC electrode array and the water-oil interface wherein the AC electrode array is positioned parallel to the interface which acts as a grounded electrode. The emulsion is introduced into the AC field in an evenly distributed manner at the interface. The AC field promotes drop-drop and drop-interface coalescence of the water phase in the entering emulsion. The continuous oil phase passes upward through the perforated AC electrode array and enters a strong DC field produced between closely spaced DC electrodes in which small dispersed droplets of water entrained in the continuous phase are removed primarily by collection at hydrophilic DC electrodes. Large droplets of water collected by the electrodes migrate downward through the AC electrode array to the interface. All phase separation mechanisms are utilized to accomplish more complete phase separation.

  9. Undergraduate Chemistry Education: Report of an ACS Presidential Symposium

    ERIC Educational Resources Information Center

    Polik, William F.

    2006-01-01

    The American Chemical Society (ACS) Presidential Symposium, Envisioning Undergraduate Chemistry Education in 2015 was organized by the ACS Committee on Professional Training (CPT), in response to the challenge to envision the chemistry enterprise in 2015. The need for more diverse role models at all levels is emphasized, including high school…

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

    SciTech Connect

    Miyamoto, R.

    2010-10-01

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

  11. 24 CFR Appendices A-C to Subtitle A - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false A Appendices A-C to Subtitle A Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development Appendices A-C to Subtitle A...

  12. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF... 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....

  13. Equivalent circuit models for ac impedance data analysis

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    A least-squares fitting routine has been developed for the analysis of ac impedance data. It has been determined that the checking of the derived equations for a particular circuit with a commercially available electronics circuit program is essential. As a result of the investigation described, three equivalent circuit models were selected for use in the analysis of ac impedance data.

  14. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    SciTech Connect

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  15. Sustainable AC/AC hybrid electrochemical capacitors in aqueous electrolyte approaching the performance of organic systems

    NASA Astrophysics Data System (ADS)

    Abbas, Qamar; Babuchowska, Paulina; Frąckowiak, Elżbieta; Béguin, François

    2016-09-01

    A high energy hybrid AC/AC electrochemical capacitor has been realized in aqueous Li2SO4+KI electrolyte mixture. Owing to the redox processes associated with the 2I-/I2 system, the positive electrode operates in narrow potential range and displays high capacity. During prolonged potentiostatic floating at 1.6 V, the hybrid cell demonstrates remarkably stable capacitance and resistance. Analyses by temperature programmed desorption after floating at 1.6 V proved that oxidation of the positive AC electrode is prevented by the use of Li2SO4+KI, which enables the maximum potential of this electrode to be shifted below the water oxidation potential. When charged at 0.2 A g-1 up to U = 1.6 V, the hybrid cell displays a high capacitance of 75 F g-1 (300 F g-1 per mass of one electrode) compared to 47 F g-1 (188 F g-1 per mass of one electrode) for a symmetric cell in Li2SO4. At 0.2 A g-1 up to 1.6 V, the hybrid capacitor in Li2SO4+KI displays an energy density of 26 Wh kg-1 which approaches the energy density of 30.9 Wh kg-1 measured when the same carbon is implemented in a capacitor using TEABF4/ACN electrolyte and charged up to 2.5 V.

  16. Cytotoxicity of 213Bi- and 225Ac-immunoconjugates.

    PubMed

    Kaspersen, F M; Bos, E; Doornmalen, A V; Geerlings, M W; Apostolidis, C; Molinet, R

    1995-06-01

    This paper describes in vitro cytotoxicity experiments with 213Bi- and 225Ac-immunoconjugates on the human epidermoid tumour cell line A431 using a blood group A-reactive murine IgG (2D11) as the specific antibody and MOPC 21 as the control antibody. With both radionuclides, specific cell-killing was achieved. The observed cytotoxicity of 213Bi (T1/2 - 47 min) indicates that this radionuclide is a useful alternative for the alpha-emitter 212Bi in the treatment of blood-borne malignancies. 225Ac-immunoconjugates (T1/2 of 225Ac is 10 days) may be applicable for the treatment of solid tumours, since the daughter radionuclides of 225Ac contribute to the cytotoxic efficacy by a field effect (i.e. toxicity in an area distal from the antibody-binding site). The lack of an adequate chelator for 225Ac is a major drawback.

  17. The A to Z of A/C plasmids.

    PubMed

    Harmer, Christopher J; Hall, Ruth M

    2015-07-01

    Plasmids belonging to incompatibility groups A and C (now A/C) were among the earliest to be associated with antibiotic resistance in Gram-negative bacteria. A/C plasmids are large, conjugative plasmids with a broad host range. The prevalence of A/C plasmids in collections of clinical isolates has revealed their importance in the dissemination of extended-spectrum β-lactamases and carbapenemases. They also mobilize SGI1-type resistance islands. Revived interest in the family has yielded many complete A/C plasmid sequences, revealing that RA1, designated A/C1, is different from the remainder, designated A/C2. There are two distinct A/C2 lineages. Backbones of 128-130 kb include over 120 genes or ORFs encoding proteins of at least 100 amino acids, but very few have been characterized. Genes potentially required for replication, stability and transfer have been identified, but only the replication system of RA1 and the regulation of transfer have been studied. There is enormous variety in the antibiotic resistance genes carried by A/C2 plasmids but they are usually clustered in larger regions at various locations in the backbone. The ARI-A and ARI-B resistance islands are always at a specific location but have variable content. ARI-A is only found in type 1 A/C2 plasmids, which disseminate blaCMY-2 and blaNDM-1 genes, whereas ARI-B, carrying the sul2 gene, is found in both type 1 and type 2. This review summarizes current knowledge of A/C plasmids, and highlights areas of research to be considered in the future.

  18. An Ac transposon system based on maize chromosome 4S for isolating long-distance-transposed Ac tags in the maize genome.

    PubMed

    Wang, Fei; Li, Zhaoying; Fan, Jun; Li, Pengfei; Hu, Wei; Wang, Gang; Xu, Zhengkai; Song, Rentao

    2010-12-01

    Transposon tagging is an important tool for gene isolation and functional studies. In maize, several transposon-tagging systems have been developed, mostly using Activator/Dissociation (Ac/Ds) and Mutator systems. Here, we establish another Ac-based transposon system with the donor Ac tightly linked with sugary1 (su1) on maize chromosome 4S. Newly transposed Ac (tr-Acs) were detected based on a negative dosage effect, and long-distance-transposed Ac events were identified and isolated from the donor Ac by a simple backcross scheme. In this study, we identified 208 independent long-distance-transposed Ac lines. Thirty-one flanking sequences of these tr-Acs were isolated and localized in the maize genome. As found in previous studies, the tr-Acs preferentially inserted into genic sequences. The distribution of tr-Acs is not random. In our study, the tr-Acs preferentially transposed into chromosomes 1, 2, 9 and 10. We discuss the preferential distribution of tr-Acs from Ac systems. Our system is complementary to two other Ac-based regional-mutagenesis systems in maize, and the combined use of these systems will achieve an even and high-density distribution of Ac elements throughout the maize genome for functional-genomics studies.

  19. Safety assessment of Cry1Ab/Ac fusion protein.

    PubMed

    Xu, Wentao; Cao, Sishuo; He, Xiaoyun; Luo, Yunbo; Guo, Xing; Yuan, Yanfang; Huang, Kunlun

    2009-07-01

    Cry1ab/ac gene was fused by both the cry1ab gene (GenBank Accession No. X54939) and the cry1ac gene (GenBank Accession No. Y09787), which was widely used in genetically modified (GM) rice, cotton, maize and so on. In order to support the safety assessment of GM food or feed products containing Cry1Ab/Ac protein, sufficient quantities of Cry1Ab/Ac protein were produced in Escherichia coli for in vitro evaluation and animal studies. The Cry1Ab/Ac protein does not possess the characteristics associated with food toxins or allergens, i.e., it has no sequence homology with any known allergens or toxins, and no N-glycosylation sites, can be rapidly degraded in gastric and intestinal fluids, and is devoid of adverse effects in mice by gavage at a high dose level of 5g (Cry1Ab/Ac protein)/kg body weight. In conclusion, there is a reasonable certainty of no harm resulting from the inclusion of the Cry1Ab/Ac protein in human food or animal feed.

  20. Trapping polar molecules in an ac trap

    SciTech Connect

    Bethlem, Hendrick L.; Veldhoven, Jacqueline van; Schnell, Melanie; Meijer, Gerard

    2006-12-15

    Polar molecules in high-field seeking states cannot be trapped in static traps as Maxwell's equations do not allow a maximum of the electric field in free space. It is possible to generate an electric field that has a saddle point by superposing an inhomogeneous electric field to an homogeneous electric field. In such a field, molecules are focused along one direction, while being defocused along the other. By reversing the direction of the inhomogeneous electric field the focusing and defocusing directions are reversed. When the fields are being switched back and forth at the appropriate rate, this leads to a net focusing force in all directions. We describe possible electrode geometries for creating the desired fields and discuss their merits. Trapping of {sup 15}ND{sub 3} ammonia molecules in a cylindrically symmetric ac trap is demonstrated. We present measurements of the spatial distribution of the trapped cloud as a function of the settings of the trap and compare these to both a simple model assuming a linear force and to full three-dimensional simulations of the experiment. With the optimal settings, molecules within a phase-space volume of 270 mm{sup 3} (m/s){sup 3} remain trapped. This corresponds to a trap depth of about 5 mK and a trap volume of about 20 mm{sup 3}.

  1. Influence of induced-charge electrokinetic phenomena on the dielectrophoretic assembly of gold nanoparticles in a conductive-island-based microelectrode system.

    PubMed

    Ding, Haitao; Liu, Weiyu; Shao, Jinyou; Ding, Yucheng; Zhang, Liangliang; Niu, Jiqiang

    2013-10-01

    Metal nanoparticles in a liquid suspension can be assembled dielectrophoretically (DEP) into nanoparticle chains, which can serve as electrical functional microwires connecting isolated and conductive elements to an electrode pair, as used in wet electronics, bioelectronics, and biochemical sensors. The frequency-dependent morphology of these nanoparticle chains assembled between an electrode pair has even been attributed to the decreasing magnitude of alternating current electroosmosis (ACEO) flow velocity with driving frequency. For instance, highly oriented nanoparticle nanowires can be generated by DEP assembly only at a high frequency, which induces a negligible small ACEO above the electrode surface, corresponding to fewer nanoparticles transported to the assembly region. In this study, attention is focused on the formation of nanoparticle chains in a conductive-island-based microelectrode system. It is worth noting that the intrusion of an island entity can bring about further double-layer polarization and induced charge electroosmosis flow (ICEO) around this conductive object, which exerts a significant influence on DEP assembly. In our experiments, the ends of nanoparticle chains are always extended onto the metal surfaces at 50 kHz, and their central parts become slender at 150 kHz. Meanwhile, wire-shaped particle clusters aligned along the direction of local field lines are more densely distributed at the island rims than that growing from the electrode edges. Consequently, a series of numerical modeling based on the theory of induced charge electrokinetic phenomena are introduced to account for these regular experimental results, including the double-layer charging effect at the metal/electrolyte interface, ACEO, ICEO, and electrothermal flow. Mutual DEP is also treated as an important factor affecting DEP behavior when neighboring particles are approaching one another. The results from the theoretical study are in good agreement with the experimental

  2. Cyclotron production of Ac-225 for targeted alpha therapy.

    PubMed

    Apostolidis, C; Molinet, R; McGinley, J; Abbas, K; Möllenbeck, J; Morgenstern, A

    2005-03-01

    The feasibility of producing Ac-225 by proton irradiation of Ra-226 in a cyclotron through the reaction Ra-226(p,2n)Ac-225 has been experimentally demonstrated for the first time. Proton energies were varied from 8.8 to 24.8 MeV and cross-sections were determined by radiochemical analysis of reaction yields. Maximum yields were reached at incident proton energies of 16.8 MeV. Radiochemical separation of Ac-225 from the irradiated target yielded a product suitable for targeted alpha therapy of cancer.

  3. Cyclotron production of Ac-225 for targeted alpha therapy.

    PubMed

    Apostolidis, C; Molinet, R; McGinley, J; Abbas, K; Möllenbeck, J; Morgenstern, A

    2005-03-01

    The feasibility of producing Ac-225 by proton irradiation of Ra-226 in a cyclotron through the reaction Ra-226(p,2n)Ac-225 has been experimentally demonstrated for the first time. Proton energies were varied from 8.8 to 24.8 MeV and cross-sections were determined by radiochemical analysis of reaction yields. Maximum yields were reached at incident proton energies of 16.8 MeV. Radiochemical separation of Ac-225 from the irradiated target yielded a product suitable for targeted alpha therapy of cancer. PMID:15607913

  4. ISTTOK upgrade towards AC and remote operation

    NASA Astrophysics Data System (ADS)

    Fernandes, H.; Silva, C.; Carvalho, B.; Sousa, J.; Valcárcel, D.; Neto, A.; Fortunato, J.; Carvalho, I.; Varandas, C. A. F.

    2006-12-01

    ISTTOK has performed one of the earliest experiments of AC tokamak operation showing that long discharges could be produced merely with inductive current drive. However, due to the design of the machine, the data acquisition system and the power supplies, a limit of 250 ms (six times the nominal forward shot duration) is currently imposed. In this paper the relevant constrains to attain current operation up to the limit of the stable toroidal magnetic field (3s) are discussed and the work being carried out to achieve this goal is presented. The conditions that shall be accomplished are: (i) removing the power deposited on the limiters; (ii) density control through gas puffing and monitoring the recycling from the walls; (iii) assessment of the free magnetic flux available on the iron core (Wmax=0.2 Vs); (iv) reformulation of the data acquisition system towards an event driven philosophy maintaining the actual distributed architecture but allowing a real-time control; (v) active control of the equilibrium magnetic fields implementing a digital plasma position estimator and actuator through new power supplies for the poloidal magnetic fields. As a new high level software was needed to implement all this features, the ISTTOK data acquisition system and control has been totally redesigned in JAVA/SQL database technology and time stamps events were adopted to catalogue the data. This software has been design keeping in mind the needs for remote participation and operation of the machine. Therefore, a cooperative environment has been implemented where several persons can be connected together to the platform, programming their own devices and exchanging knowledge or opinions through an embedded chat.

  5. ISTTOK upgrade towards AC and remote operation

    SciTech Connect

    Fernandes, H.; Silva, C.; Carvalho, B.; Sousa, J.; Valcarcel, D.; Neto, A.; Fortunato, J.; Carvalho, I.; Varandas, C. A. F.

    2006-12-04

    ISTTOK has performed one of the earliest experiments of AC tokamak operation showing that long discharges could be produced merely with inductive current drive. However, due to the design of the machine, the data acquisition system and the power supplies, a limit of 250 ms (six times the nominal forward shot duration) is currently imposed.In this paper the relevant constrains to attain current operation up to the limit of the stable toroidal magnetic field (3s) are discussed and the work being carried out to achieve this goal is presented.The conditions that shall be accomplished are: (i) removing the power deposited on the limiters; (ii) density control through gas puffing and monitoring the recycling from the walls; (iii) assessment of the free magnetic flux available on the iron core (Wmax=0.2 Vs); (iv) reformulation of the data acquisition system towards an event driven philosophy maintaining the actual distributed architecture but allowing a real-time control; (v) active control of the equilibrium magnetic fields implementing a digital plasma position estimator and actuator through new power supplies for the poloidal magnetic fields. As a new high level software was needed to implement all this features, the ISTTOK data acquisition system and control has been totally redesigned in JAVA/SQL database technology and time stamps events were adopted to catalogue the data. This software has been design keeping in mind the needs for remote participation and operation of the machine. Therefore, a cooperative environment has been implemented where several persons can be connected together to the platform, programming their own devices and exchanging knowledge or opinions through an embedded chat.

  6. Initial Tests of an AC Dipole for the Tevatron

    SciTech Connect

    Miyamoto, R.; Kopp, S.; Jansson, A.; Syphers, M.

    2006-11-20

    The AC dipole is a device to diagnose transverse motions of a beam. It can achieve large-amplitude oscillations without two inevitable problems of conventional kicker/pinger magnets: decoherence and emittance growth. While not the first synchrotron to operate with an AC dipole, the Tevatron can now make use of its recently upgraded BPM system, providing unprecedented resolution for use with an AC dipole, to measure both linear and nonlinear properties of the accelerator. Plans are to provide AC dipole systems for both transverse degrees of freedom. Preliminary tests have been done using an audio power amplifier with an existing vertical pinger magnet, producing oscillation amplitudes up to 2{sigma} at 150 GeV. In this paper, we will present the configuration of this system. We also show the analysis of a first few data sets, including the direct measurement of beta functions at BPM locations.

  7. Initial Tests of an AC Dipole for the Tevatron

    NASA Astrophysics Data System (ADS)

    Miyamoto, R.; Jansson, A.; Kopp, S.; Syphers, M.

    2006-11-01

    The AC dipole is a device to diagnose transverse motions of a beam. It can achieve large-amplitude oscillations without two inevitable problems of conventional kicker/pinger magnets: decoherence and emittance growth. While not the first synchrotron to operate with an AC dipole, the Tevatron can now make use of its recently upgraded BPM system, providing unprecedented resolution for use with an AC dipole, to measure both linear and nonlinear properties of the accelerator. Plans are to provide AC dipole systems for both transverse degrees of freedom. Preliminary tests have been done using an audio power amplifier with an existing vertical pinger magnet, producing oscillation amplitudes up to 2σ at 150 GeV. In this paper, we will present the configuration of this system. We also show the analysis of a first few data sets, including the direct measurement of beta functions at BPM locations.

  8. Initial tests of an AC dipole for the Tevatron

    SciTech Connect

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

    2006-06-01

    The AC dipole is a device to diagnose transverse motions of a beam. It can achieve large-amplitude oscillations without two inevitable problems of conventional kicker/pinger magnets: decoherence and emittance growth. While not the first synchrotron to operate with an AC dipole, the Tevatron can now make use of its recently upgraded BPM system, providing unprecedented resolution for use with an AC dipole, to measure both linear and nonlinear properties of the accelerator. Plans are to provide AC dipole systems for both transverse degrees of freedom. Preliminary tests have been done using an audio power amplifier with an existing vertical pinger magnet, producing oscillation amplitudes up to 2{sigma} at 150 GeV. In this paper, we will present the configuration of this system. We also show the analysis of a first few data sets, including the direct measurement of beta functions at BPM locations.

  9. High-Frequency ac Power-Distribution System

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.; Mildice, James

    1987-01-01

    Loads managed automatically under cycle-by-cycle control. 440-V rms, 20-kHz ac power system developed. System flexible, versatile, and "transparent" to user equipment, while maintaining high efficiency and low weight. Electrical source, from dc to 2,200-Hz ac converted to 440-V rms, 20-kHz, single-phase ac. Power distributed through low-inductance cables. Output power either dc or variable ac. Energy transferred per cycle reduced by factor of 50. Number of parts reduced by factor of about 5 and power loss reduced by two-thirds. Factors result in increased reliability and reduced costs. Used in any power-distribution system requiring high efficiency, high reliability, low weight, and flexibility to handle variety of sources and loads.

  10. Fast electric dipole transitions in Ra-Ac nuclei

    SciTech Connect

    Ahmad, I.

    1985-01-01

    Lifetime of levels in /sup 225/Ra, /sup 225/Ac, and /sup 227/Ac have been measured by delayed coincidence techniques and these have been used to determine the E1 gamma-ray transition probabilities. The reduced E1 transition probabilities. The reduced E1 transition probabilities in /sup 225/Ra and /sup 225/Ac are about two orders of magnitude larger than the values in mid-actinide nuclei. On the other hand, the E1 rate in /sup 227/Ac is similar to those measured in heavier actinides. Previous studies suggest the presence of octupole deformation in all the three nuclei. The present investigation indicates that fast E1 transitions occur for nuclei with octupole deformation. However, the studies also show that there is no one-to-one correspondence between E1 rate and octupole deformation. 13 refs., 4 figs.

  11. Effect of ac on current-induced domain wall motion

    NASA Astrophysics Data System (ADS)

    Kim, W. J.; Lee, T. D.; Choa, S. H.; Seo, S. M.; Lee, K. J.

    2007-05-01

    Saitoh et al. [Nature (London) 432, 203 (2004)] have reported the experimental result showing the interplay of a transverse domain wall with an electrical ac of megahertz-range frequencies. They observed a single peak of resistance in the frequency range and interpreted it with a nonadiabatic spin torque. It was argued that an ac current can induce a micrometer-range displacement of domain wall. We reconstructed the experiment in micromagnetic simulations considering the local nonzero nonadiabatic spin torque. We could not observe either an explicit single peak in the frequency-dependent resistance or an eventual displacement of domain wall by use of an ac. It indicates the local nonadiabatic torque is inappropriate to explain the experimental results of ac-induced domain wall motion. Other approaches such as the nonlocal nonadiabatic spin torque may be needed.

  12. 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.

  13. Basic concepts of induced AC voltages on pipelines

    SciTech Connect

    Kirkpatrick, E.L.

    1995-07-01

    The phenomena of induced AC on pipelines sharing common rights-of-way with overhead high-voltage electrical transmission power lines is discussed. Basic concepts and techniques for personnel safety and some pipeline protective measures are reviewed.

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  15. Alternating parity structure in doubly odd /sup 218/Ac

    SciTech Connect

    Debray, M.E.; Davidson, M.; Kreiner, A.J.; Davidson, J.; Falcone, G.; Hojman, D.; Santos, D.

    1989-03-01

    States in doubly odd /sup 218/Ac have been studied using in-beam ..cap alpha..-, ..gamma..-, and e/sup -/-spectroscopy techniques mainly through the /sup 209/Bi(/sup 12/C,3n)= fusion-evaporation reaction. /sup 218/Ac shows a band structure, with interleaved states of alternating parities connected by enhanced B(E1) transitions, which is strikingly similar to the one in its isotone /sup 217/Ra.

  16. Search for {beta}-delayed fission of {sup 228}Ac

    SciTech Connect

    Xu Yanbing; Ding Huajie; Yuan Shuanggui; Yang Weifan; Niu Yanning; Li Yingjun; Xiao Yonghou; Zhang Shengdong; Lu Xiting

    2006-10-15

    Radium was radiochemically separated from natural thorium. Thin {sup 228}Ra{yields}{beta}{sup -228}Ac sources were prepared and exposed to mica fission track detectors, and measured by an HPGe {gamma}-ray detector. The {beta}-delayed fission events of {sup 228}Ac were observed and its {beta}-delayed fission probability was found to be (5{+-}2)x10{sup -12}.

  17. Development of an AC Module System: Final Technical Report

    SciTech Connect

    Suparna Kadam; Miles Russell

    2012-06-15

    The GreenRay Inc. program focused on simplifying solar electricity and making it affordable and accessible to the mainstream population. This was accomplished by integrating a solar module, micro-inverter, mounting and monitoring into a reliable, 'plug and play' AC system for residential rooftops, offering the following advantages: (1) Reduced Cost: Reduction in installation labor with fewer components, faster mounting, faster wiring. (2) Maximized Energy Production: Each AC Module operates at its maximum, reducing overall losses from shading, mismatch, or module downtime. (3) Increased Safety. Electrical and fire safety experts agree that AC Modules have significant benefits, with no energized wiring or live connections during installation, maintenance or emergency conditions. (4) Simplified PV for a Broader Group of Installers. Dramatic simplification of design and installation of a solar power system, enabling faster and more efficient delivery of the product into the market through well-established, mainstream channels. This makes solar more accessible to the public. (5) Broadened the Rooftop Market: AC Modules enable solar for many homes that have shading, split roofs, or obstructions. In addition, due to the smaller building block size of 200W vs. 1000W, homeowners with budget limitations can start small and add to their systems over time. Through this DOE program GreenRay developed the all-in-one AC Module system with an integrated PV Module and microinverter, custom residential mounting and performance monitoring. Development efforts took the product from its initial concept, through prototypes, to a commercial product sold and deployed in the residential market. This pilot deployment has demonstrated the technical effectiveness of the AC Module system in meeting the needs and solving the problems of the residential market. While more expensive than the traditional central inverter systems at the pilot scale, the economics of AC Modules become more and more

  18. Diffusive suppression of AC-Stark shifts in atomic magnetometers

    PubMed Central

    Sulai, I. A.; Wyllie, R.; Kauer, M.; Smetana, G. S.; Wakai, R. T.; Walker, T. G.

    2016-01-01

    In atomic magnetometers, the vector AC-Stark shift associated with circularly polarized light generates spatially varying effective magnetic fields, which limit the magnetometer response and serve as sources of noise. We describe a scheme whereby optically pumping a small subvolume of the magnetometer cell and relying on diffusion to transport polarized atoms allows a magnetometer to be operated with minimal sensitivity to the AC-Stark field. © 2013 Optical Society of America PMID:23503278

  19. Accelerator Production of {sup 225}Ac For Alpha-Immunotherapy

    SciTech Connect

    Weidner, J. W.; Nortier, F. M.; Bach, H. T.; John, K. D.; Couture, A.; Ullmann, J. L.; Fassbender, M. E.; Goff, G. S.; Taylor, W.; Valdez, F.; Wolfsberg, L. E.; Cisneros, M.; Dry, D.; Gallegos, M.; Gritzo, R.; Bitteker, L. J.; Wender, S.; Baty, R. S.

    2011-06-01

    {sup 225}Ac has tremendous potential for the treatment of metastatic cancer due to the four alpha-particles emitted during its decay to stable {sup 209}Bi. Additionally, it is one of the few alpha-emitters being considered for clinical trials. The anticipated {sup 225}Ac demand for these trials is expected to far exceed the annual worldwide supply of approximately 1,000 mCi/yr. Consequently, the DOE Office of Science has funded investigations into accelerator-based production of {sup 225}Ac. Existing {sup 232}Th(p,x){sup 225}Ac cross section data indicate that up to 480 mCi/day of {sup 225}Ac could be created by bombarding a thick target of natural thorium with 100 MeV protons at the Los Alamos Isotope Production Facility. To verify these predictions, experiments are underway at the Los Alamos Neutron Science Center to measure the {sup 232}Th(p,x){sup 225}Ac production cross sections for protons in the energy range 40-200 MeV, and at 800 MeV. For 800 MeV protons, preliminary results indicate that the {sup 225}Ac production cross section is 12.4{+-}0.6 mb and the {sup 225}Ra production cross section is 3.2{+-}0.2 mb. Moreover, preliminary results suggest that the {sup 227}Ac production cross section is 16{+-}1 mb. Experiments to measure these same cross sections at proton energies below 200 MeV are planned for the last half of calendar year 2010.

  20. Accelerator Production of 225Ac For Alpha-Immunotherapy

    NASA Astrophysics Data System (ADS)

    Weidner, J. W.; Nortier, F. M.; Bach, H. T.; John, K. D.; Couture, A.; Ullmann, J. L.; Fassbender, M. E.; Goff, G. S.; Taylor, W.; Valdez, F.; Wolfsberg, L. E.; Cisneros, M.; Dry, D.; Gallegos, M.; Gritzo, R.; Bitteker, L. J.; Wender, S.; Baty, R. S.

    2011-06-01

    225Ac has tremendous potential for the treatment of metastatic cancer due to the four alpha-particles emitted during its decay to stable 209Bi. Additionally, it is one of the few alpha-emitters being considered for clinical trials. The anticipated 225Ac demand for these trials is expected to far exceed the annual worldwide supply of approximately 1,000 mCi/yr. Consequently, the DOE Office of Science has funded investigations into accelerator-based production of 225Ac. Existing 232Th(p,x)225Ac cross section data indicate that up to 480 mCi/day of 225Ac could be created by bombarding a thick target of natural thorium with 100 MeV protons at the Los Alamos Isotope Production Facility. To verify these predictions, experiments are underway at the Los Alamos Neutron Science Center to measure the 232Th(p,x)225Ac production cross sections for protons in the energy range 40-200 MeV, and at 800 MeV. For 800 MeV protons, preliminary results indicate that the 225Ac production cross section is 12.4±0.6 mb and the 225Ra production cross section is 3.2±0.2 mb. Moreover, preliminary results suggest that the 227Ac production cross section is 16±1 mb. Experiments to measure these same cross sections at proton energies below 200 MeV are planned for the last half of calendar year 2010.

  1. Diagnostics of the Fermilab Tevatron using an AC dipole

    NASA Astrophysics Data System (ADS)

    Miyamoto, Ryoichi

    The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for the Tevatron, a fast-oscillating (f˜20 kHz) dipole magnet which can be adiabatically turned on and off to establish sustained coherent oscillations of the beam particles without affecting the transverse emittance. By utilizing an existing magnet and a higher power audio amplifier, the cost of the Tevatron AC dipole system became relatively inexpensive. We discuss corrections which must be applied to the driven oscillation measurements to obtain the proper interpretation of beam optical parameters from AC dipole studies. After successful operations of the Tevatron AC dipole system, AC dipole systems, similar to that in the Tevatron, will be build for the CERN LHC. We present several measurements of linear optical parameters (beta function and phase advance) for the Tevatron, as well as studies of non-linear perturbations from sextupole and octupole elements.

  2. 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

  3. 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.

  4. Update on bedside ultrasound (US) diagnosis of acute cholecystitis (AC).

    PubMed

    Zenobii, Maria Francesca; Accogli, Esterita; Domanico, Andrea; Arienti, Vincenzo

    2016-03-01

    Acute cholecystitis (AC) represents a principal cause of morbidity worldwide and is one of the most frequent reasons for hospitalization due to gastroenteric tract diseases. AC should be suspected in presence of clinical signs and of gallstones on an imaging study. Upper abdominal US represents the first diagnostic imaging step in the case of suspected AC. Computed tomography (CT) with intravenous contrast (IV) or magnetic resonance imaging (MRI) with gadolinium contrast and technetium hepatobiliary iminodiacetic acid (Tc-HIDA) can be employed to exclude complications. US examination should be performed with right subcostal oblique, with longitudinal and intercostal scans. Normal gallbladder US findings and AC major and minor US signs are described. Polyps, sludge and gallbladder wall thickening represent the more frequent pitfalls and they must be differentiated from stones, duodenal artifacts and many other non-inflammatory conditions that cause wall thickening, respectively. By means of bedside ultrasound, the finding of gallstones in combination with acute pain, when the clinician presses the gallbladder with the US probe (the sonographic Murphy's sign), has a 92.2 % positive predictive value for AC. In our preliminary experience, bedside US-performed by echoscopy (ES) and/or point-of-care US (POCUS) demonstrated good reliability in detecting signs of AC, and was always integrated with physical examination and performed by a skilled operator.

  5. Temperature integration at the AC thermosensory neurons in Drosophila.

    PubMed

    Tang, Xin; Platt, Michael D; Lagnese, Christopher M; Leslie, Jennifer R; Hamada, Fumika N

    2013-01-16

    Temperature sensation has a strong impact on animal behavior and is necessary for animals to avoid exposure to harmful temperatures. It is now well known that thermoTRP (transient receptor potential) channels in thermosensory neurons detect a variable range of temperature stimuli. However, little is known about how a range of temperature information is relayed and integrated in the neural circuits. Here, we show novel temperature integration between two warm inputs via Drosophila TRPA channels, TRPA1 and Pyrexia (Pyx). The internal AC (anterior cell) thermosensory neurons, which express TRPA1, detect warm temperatures and mediate temperature preference behavior. We found that the AC neurons were activated twice when subjected to increasing temperatures. The first response was at ∼25°C via TRPA1 channel, which is expressed in the AC neurons. The second response was at ∼27°C via the second antennal segments, indicating that the second antennal segments are involved in the detection of warm temperatures. Further analysis reveals that pyx-Gal4-expressing neurons have synapses on the AC neurons and that mutation of pyx eliminates the second response of the AC neurons. These data suggest that AC neurons integrate both their own TRPA1-dependent temperature responses and a Pyx-dependent temperature response from the second antennal segments. Our data reveal the first identification of temperature integration, which combines warm temperature information from peripheral to central neurons and provides the possibility that temperature integration is involved in the plasticity of behavioral outputs.

  6. Diagnostics of the Fermilab Tevatron using an AC dipole

    SciTech Connect

    Miyamoto, Ryoichi

    2008-08-01

    The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for the Tevatron, a fast-oscillating (f ~ 20 kHz) dipole magnet which can be adiabatically turned on and off to establish sustained coherent oscillations of the beam particles without affecting the transverse emittance. By utilizing an existing magnet and a higher power audio amplifier, the cost of the Tevatron AC dipole system became relatively inexpensive. We discuss corrections which must be applied to the driven oscillation measurements to obtain the proper interpretation of beam optical parameters from AC dipole studies. After successful operations of the Tevatron AC dipole system, AC dipole systems, similar to that in the Tevatron, will be build for the CERN LHC. We present several measurements of linear optical parameters (beta function and phase advance) for the Tevatron, as well as studies of non-linear perturbations from sextupole and octupole elements.

  7. Sequential control by speed drive for ac motor

    NASA Astrophysics Data System (ADS)

    Barsoum, Nader

    2012-11-01

    The speed drive for ac motor is widely used in the industrial field to allow direct control for the speed and torque without any feedback from the motor shaft. By using the ABB ACS800 speed drive unit, the speed and torque can be controlled using sequential control method. Sequential control is one of the application control method provided in the ABB ACS800 Drive, where a set of events or action performed in a particular order one after the other to control the speed and torque of the ac motor. It was claimed that sequential control method is using the preset seven constant speeds being provided in ABB ACS800 drive to control the speed and torque in a continuous and sequential manner. The characteristics and features of controlling the speed and torque using sequential control method can be investigated by observing the graphs and curves plotted which are obtained from the practical result. Sequential control can run either in the Direct Torque Control (DTC) or Scalar motor control mode. By using sequential control method, the ABB ACS800 drive can be programmed to run the motor automatically according to the time setting of the seven preset constant speeds. Besides, the intention of this project is to generate a new form of the experimental set up.

  8. Equivalent Electrical Circuit Representations of AC Quantized Hall Resistance Standards

    PubMed Central

    Cage, M. E.; Jeffery, A.; Matthews, J.

    1999-01-01

    We use equivalent electrical circuits to analyze the effects of large parasitic impedances existing in all sample probes on four-terminal-pair measurements of the ac quantized Hall resistance RH. The circuit components include the externally measurable parasitic capacitances, inductances, lead resistances, and leakage resistances of ac quantized Hall resistance standards, as well as components that represent the electrical characteristics of the quantum Hall effect device (QHE). Two kinds of electrical circuit connections to the QHE are described and considered: single-series “offset” and quadruple-series. (We eliminated other connections in earlier analyses because they did not provide the desired accuracy with all sample probe leads attached at the device.) Exact, but complicated, algebraic equations are derived for the currents and measured quantized Hall voltages for these two circuits. Only the quadruple-series connection circuit meets our desired goal of measuring RH for both ac and dc currents with a one-standard-deviation uncertainty of 10−8 RH or less during the same cool-down with all leads attached at the device. The single-series “offset” connection circuit meets our other desired goal of also measuring the longitudinal resistance Rx for both ac and dc currents during that same cool-down. We will use these predictions to apply small measurable corrections, and uncertainties of the corrections, to ac measurements of RH in order to realize an intrinsic ac quantized Hall resistance standard of 10−8 RH uncertainty or less.

  9. 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.

  10. 21 CFR 880.6320 - AC-powered medical examination light.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered medical examination light. 880.6320... Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered medical examination light is an AC-powered device intended for medical purposes that is used to illuminate...

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

    PubMed

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

    2015-10-01

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

  12. Modelling ac ripple currents in HTS coated conductors

    NASA Astrophysics Data System (ADS)

    Xu, Zhihan; Grilli, Francesco

    2015-10-01

    Dc transmission using high temperature superconducting (HTS) coated conductors (CCs) offers a promising solution to the globally growing demand for effective, reliable and economic transmission of green energy up to the gigawatt level over very long distances. The credible estimation of the losses and thereby the heat dissipation involved, where ac ripples (introduced in rectification/ac-dc conversion) are viewed as a potential source of notable contribution, is highly essential for the rational design of practical HTS dc transmission cables and corresponding cryogenic systems to fulfil this demand. Here we report a targeted modelling study into the ac losses in a HTS CC subject to dc and ac ripple currents simultaneously, by solving Maxwell’s equations using the finite element method (FEM) in the commercial software package COMSOL. It is observed that the instantaneous loss exhibits only one peak per cycle in the HTS CC subject to sinusoidal ripples, given that the amplitude of the ac ripples is smaller than approximately 20% of that of the dc current. This is a distinct contrast to the usual observation of two peaks per cycle in a HTS CC subject to ac currents only. The unique mechanism is also revealed, which is directly associated with the finding that, around any local minima of the applied ac ripples, the critical state of -J c is never reached at the edges of the HTS CC, as it should be according to the Bean model. When running further into the longer term, it is discovered that the ac ripple loss of the HTS CC in full-wave rectification decays monotonically, at a speed which is found to be insensitive to the frequency of the applied ripples within our targeted situations, to a relatively low level of approximately 1.38 × 10-4 W m-1 in around 1.7 s. Comparison between this level and other typical loss contributions in a HTS dc cable implies that ac ripple currents in HTS CCs should only be considered as a minor source of dissipation in superconducting dc

  13. Muc5ac Mucin Expression During Rat Skin Development

    PubMed Central

    Ferretti, V.; Segal-Eiras, A.; Barbeito, C.G.; Croce, M.V.

    2015-01-01

    Some mucin genes have been detected during human embryonic and fetal organ development; however, little is known about mucin expression in epidermal development, neither in humans nor in other species. The present research was developed to explore Muc5ac skin expression during pre- and post-natal rat development. Immunohistochemistry (IHC), Western blotting (WB) and RT-PCR were employed. By IHC, Muc5ac protein was found early in embryonic epidermis from day 13 of gestation until seven days after birth when the surface epidermis became negative and the reaction was restricted to secreting sebum cells. In coincidence with IHC findings, WB analysis showed a band at approximately 200KDa at the same periods of development. Results were also confirmed by RT-PCR. Muc5ac expression in rat embryonic epidermis suggests that Muc5ac may play a protective role in embryonic skin previous to birth which may be replaced by pile covering. To our knowledge, this is the first report that confirmed Muc5ac expression during skin development. PMID:25820562

  14. AC propulsion system for an electric vehicle, phase 2

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1983-01-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  15. 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 conductivity (σac) 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.

  16. 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.

  17. Oxidative coupling of methane with ac and dc corona discharges

    SciTech Connect

    Liu, C.; Marafee, A.; Hill, B.; Xu, G.; Mallinson, R.; Lobban, L.

    1996-10-01

    The oxidative coupling of methane (OCM) is being actively studied for the production of higher hydrocarbons from natural gas. The present study concentrated on the oxidative conversion of methane in an atmospheric pressure, nonthermal plasma formed by ac or dc corona discharges. Methyl radicals are formed by reaction with negatively-charged oxygen species created in the corona discharge. The selectivity to products ethane and ethylene is affected by electrode polarity, frequency, and oxygen partial pressure in the feed. Higher C{sub 2} yields were obtained with the ac corona. All the ac corona discharges are initiated at room temperature (i.e., no oven or other heat source is used), and the temperature increases to 300--500 C due to the exothermic reactions and the discharge itself. The largest C{sub 2} yield is 21% with 43.3% methane conversion and 48.3% C{sub 2} selectivity at a flowrate of 100 cm{sup 3}/min when the ac corona is at 30 Hz, 5 kV (rms) input power was used. The methane conversion may be improved to more than 50% by increasing the residence time, but the C{sub 2} selectivity decreases. A reaction mechanism including the oxidative dehydrogenation (OXD) of ethane to ethylene is presented to explain the observed phenomena. The results suggest that ac and/or dc gas discharge techniques have significant promise for improving the economics of OCM processes.

  18. Aragonite coating solutions (ACS) based on artificial seawater

    NASA Astrophysics Data System (ADS)

    Tas, A. Cuneyt

    2015-03-01

    Aragonite (CaCO3, calcium carbonate) is an abundant biomaterial of marine life. It is the dominant inorganic phase of coral reefs, mollusc bivalve shells and the stalactites or stalagmites of geological sediments. Inorganic and initially precipitate-free aragonite coating solutions (ACS) of pH 7.4 were developed in this study to deposit monolayers of aragonite spherules or ooids on biomaterial (e.g., UHMWPE, ultrahigh molecular weight polyethylene) surfaces soaked in ACS at 30 °C. The ACS solutions of this study have been developed for the surface engineering of synthetic biomaterials. The abiotic ACS solutions, enriched with calcium and bicarbonate ions at different concentrations, essentially mimicked the artificial seawater composition and started to deposit aragonite after a long (4 h) incubation period at the tropical sea surface temperature of 30 °C. While numerous techniques for the solution deposition of calcium hydroxyapatite (Ca10(PO4)6(OH)2), of low thermodynamic solubility, on synthetic biomaterials have been demonstrated, procedures related to the solution-based surface deposition of high solubility aragonite remained uncommon. Monolayers of aragonite ooids deposited at 30 °C on UHMWPE substrates soaked in organic-free ACS solutions were found to possess nano-structures similar to the mortar-and-brick-type botryoids observed in biogenic marine shells. Samples were characterized using SEM, XRD, FTIR, ICP-AES and contact angle goniometry.

  19. Cadmium-induced ethylene production and responses in Arabidopsis thaliana rely on ACS2 and ACS6 gene expression

    PubMed Central

    2014-01-01

    Background Anthropogenic activities cause metal pollution worldwide. Plants can absorb and accumulate these metals through their root system, inducing stress as a result of excess metal concentrations inside the plant. Ethylene is a regulator of multiple plant processes, and is affected by many biotic and abiotic stresses. Increased ethylene levels have been observed after exposure to excess metals but it remains unclear how the increased ethylene levels are achieved at the molecular level. In this study, the effects of cadmium (Cd) exposure on the production of ethylene and its precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and on the expression of the ACC Synthase (ACS) and ACC Oxidase (ACO) multigene families were investigated in Arabidopsis thaliana. Results Increased ethylene release after Cd exposure was directly measurable in a system using rockwool-cultivated plants; enhanced levels of the ethylene precursor ACC together with higher mRNA levels of ethylene responsive genes: ACO2, ETR2 and ERF1 also indicated increased ethylene production in hydroponic culture. Regarding underlying mechanisms, it was found that the transcript levels of ACO2 and ACO4, the most abundantly expressed members of the ACO multigene family, were increased upon Cd exposure. ACC synthesis is the rate-limiting step in ethylene biosynthesis, and transcript levels of both ACS2 and ACS6 showed the highest increase and became the most abundant isoforms after Cd exposure, suggesting their importance in the Cd-induced increase of ethylene production. Conclusions Cadmium induced the biosynthesis of ACC and ethylene in Arabidopsis thaliana plants mainly via the increased expression of ACS2 and ACS6. This was confirmed in the acs2-1acs6-1 double knockout mutants, which showed a decreased ethylene production, positively affecting leaf biomass and resulting in a delayed induction of ethylene responsive gene expressions without significant differences in Cd contents between wild-type and

  20. Thioesterification of 2-arylpropionic acids by recombinant acyl-coenzyme A synthetases (ACS1 and ACS2).

    PubMed

    Sevoz, C; Benoit, E; Buronfosse, T

    2000-04-01

    2-Arylpropionic acids are a class of frequently used nonsteroidal anti-inflammatory drugs exhibiting a potent inhibition of cyclooxygenase isoforms supported by the (+)S-enantiomer alone. Nevertheless, some of these compounds in the (-)R configuration may undergo extensive inversion of configuration to their antipode. The key molecular basis for this mechanism invokes the stereoselective formation of the coenzyme A (CoA) thioester of the 2-arylpropionic acid by long-chain acyl-CoA synthetases (ACSs). In this report, rat recombinant ACS1 and ACS2 enzymes, constitutively highly expressed in adult rat liver and brain, respectively, have been overproduced in Escherichia coli strains and purified to homogeneity to investigate the involvement of these enzymes in the thioesterification of fenoprofen and ibuprofen. Recombinant ACS1 efficiently catalyzed both nonsteroidal anti-inflammatory drugs with Michaelis-Menten parameters of K(M) = 1686 +/- 93 microM, V(max) = 353 +/- 45 nmol/min/mg protein for (-)R-ibuprofen and K(M) = 103 +/- 12 microM, V(max) = 267 +/- 10 nmol/min/mg protein for (-)R-fenoprofen, and exhibited a marked stereoselectivity in favor of the (-)R-enantiomer. Recombinant ACS2, a closely related sequence with ACS1, exhibited a lower enzymatic efficacy from 7- to 130-fold for (-)R-ibuprofen and (-)R-fenoprofen, respectively. On the basis of these findings and considering the level of tissue expression of the different long-chain ACSs, ACS1 appears to be the major enzyme involved in the first step of the chiral inversion of 2-arylpropionic acids. Nevertheless, the participation of other ACS isoforms of minor quantitative importance could not be excluded in the thioesterification of xenobiotics.

  1. Variable transposition of eight maize activator (ac) elements located on the short arm of chromosome 1.

    PubMed

    Sheridan, William F

    2011-09-01

    Eight Activator (Ac) transposable elements mapped to the maize chromosome arm 1S were assessed for Ac transposition rates. For each of the Ac stocks, plants homozygous for the single Ac element and the Ds reporter r1-sc:m3 on chromosome 10 were crossed as females by a homozygous r1-sc:m3 tester color-converted W22 line. The resulting ears produced mostly coarsely spotted kernels and a low frequency of either near-colorless fine-spotted kernels or nonspotted kernels. The relative frequency of these two types of near-colorless kernels differed among the eight Ac stocks. The extent to which increased Ac dosage results in nonspotted kernels may be Ac-specific. Although all of the Ac elements are in near-isogenic inbred W22 lines, they varied to a large extent in their transposition frequency. These differences might possibly result from structural differences among the Ac elements. Because one pair of Ac elements derived from Ac33 on chromosome arm 5S differed about 13-fold in transposition frequency and a second pair of Ac elements derived from Ac12 on chromosome arm 1S differed about 3-fold in transposition frequency, this is not a likely explanation for all eight Ac elements. The data presented here support the notion that the differences in transposition frequency of the eight Ac elements may be a reflection of variability in Ac transcription or accessibility of the transposase to the Ac element, resulting from differences in the chromatin environments wherein the Ac elements are located. This is the first report of variability in transposition rates among different Ac donor lines.

  2. 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.

  3. Flux-motion related ac losses in high Tc superconductors

    NASA Astrophysics Data System (ADS)

    Chen, Q. Y.

    1993-03-01

    The ac losses of high-temperature superconductors in the flux-depinned mixed-state have been treated using the classical magnetic diffusion equation in conjunction with various models of flux-motion. With the imaginary part representing the ac losses, the field- and frequency-dependent ac susceptibilities were investigated. The imaginary component was found to obey a scaling rule with a characteristic frequency, estimated to be about 10 exp 5-10 exp 9 Hz, that depended on the sample size and normal state resistivity. This frequency range agrees with earlier experimental results, which could not be accounted for previously based upon the notion of thermally activated hopping of vortices. The frequency scaling behaviors using flux-creep and flux-flow models are presented.

  4. AC Conductivity Studies of Lithium Based Phospho Vanadate Glasses

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

  5. Reliability of emergency ac power systems at nuclear power plants

    SciTech Connect

    Battle, R E; Campbell, D J

    1983-07-01

    Reliability of emergency onsite ac power systems at nuclear power plants has been questioned within the Nuclear Regulatory Commission (NRC) because of the number of diesel generator failures reported by nuclear plant licensees and the reactor core damage that could result from diesel failure during an emergency. This report contains the results of a reliability analysis of the onsite ac power system, and it uses the results of a separate analysis of offsite power systems to calculate the expected frequency of station blackout. Included is a design and operating experience review. Eighteen plants representative of typical onsite ac power systems and ten generic designs were selected to be modeled by fault trees. Operating experience data were collected from the NRC files and from nuclear plant licensee responses to a questionnaire sent out for this project.

  6. Theory of the ac spin-valve effect.

    PubMed

    Kochan, Denis; Gmitra, Martin; Fabian, Jaroslav

    2011-10-21

    The spin-valve complex magnetoimpedance of symmetric ferromagnet-normal-metal-ferromagnet junctions is investigated within the drift-diffusion (standard) model of spin injection. The ac magnetoresistance-the real part difference of the impedances of the parallel and antiparallel magnetization configurations-exhibits an overall damped oscillatory behavior, as an interplay of the diffusion and spin relaxation times. In wide junctions the ac magnetoresistance oscillates between positive and negative values, reflecting resonant amplification and depletion of the spin accumulation, while the line shape for thin tunnel junctions is predicted to be purely Lorentzian. The ac spin-valve effect could be a technique to extract spin transport and spin relaxation parameters in the absence of a magnetic field and for a fixed sample size. PMID:22107552

  7. Introducing high performance distributed logging service for ACS

    NASA Astrophysics Data System (ADS)

    Avarias, Jorge A.; López, Joao S.; Maureira, Cristián; Sommer, Heiko; Chiozzi, Gianluca

    2010-07-01

    The ALMA Common Software (ACS) is a software framework that provides the infrastructure for the Atacama Large Millimeter Array and other projects. ACS, based on CORBA, offers basic services and common design patterns for distributed software. Every properly built system needs to be able to log status and error information. Logging in a single computer scenario can be as easy as using fprintf statements. However, in a distributed system, it must provide a way to centralize all logging data in a single place without overloading the network nor complicating the applications. ACS provides a complete logging service infrastructure in which every log has an associated priority and timestamp, allowing filtering at different levels of the system (application, service and clients). Currently the ACS logging service uses an implementation of the CORBA Telecom Log Service in a customized way, using only a minimal subset of the features provided by the standard. The most relevant feature used by ACS is the ability to treat the logs as event data that gets distributed over the network in a publisher-subscriber paradigm. For this purpose the CORBA Notification Service, which is resource intensive, is used. On the other hand, the Data Distribution Service (DDS) provides an alternative standard for publisher-subscriber communication for real-time systems, offering better performance and featuring decentralized message processing. The current document describes how the new high performance logging service of ACS has been modeled and developed using DDS, replacing the Telecom Log Service. Benefits and drawbacks are analyzed. A benchmark is presented comparing the differences between the implementations.

  8. Modeling and Correcting the Time-Dependent ACS PSF

    NASA Technical Reports Server (NTRS)

    Rhodes, Jason; Massey, Richard; Albert, Justin; Taylor, James E.; Koekemoer, Anton M.; Leauthaud, Alexie

    2006-01-01

    The ability to accurately measure the shapes of faint objects in images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) depends upon detailed knowledge of the Point Spread Function (PSF). We show that thermal fluctuations cause the PSF of the ACS Wide Field Camera (WFC) to vary over time. We describe a modified version of the TinyTim PSF modeling software to create artificial grids of stars across the ACS field of view at a range of telescope focus values. These models closely resemble the stars in real ACS images. Using 10 bright stars in a real image, we have been able to measure HST s apparent focus at the time of the exposure. TinyTim can then be used to model the PSF at any position on the ACS field of view. This obviates the need for images of dense stellar fields at different focus values, or interpolation between the few observed stars. We show that residual differences between our TinyTim models and real data are likely due to the effects of Charge Transfer Efficiency (CTE) degradation. Furthermore, we discuss stochastic noise that is added to the shape of point sources when distortion is removed, and we present MultiDrizzle parameters that are optimal for weak lensing science. Specifically, we find that reducing the MultiDrizzle output pixel scale and choosing a Gaussian kernel significantly stabilizes the resulting PSF after image combination, while still eliminating cosmic rays/bad pixels, and correcting the large geometric distortion in the ACS. We discuss future plans, which include more detailed study of the effects of CTE degradation on object shapes and releasing our TinyTim models to the astronomical community.

  9. Advanced Sensors for Accurate, Broadband AC Voltage Metrology

    NASA Astrophysics Data System (ADS)

    Lipe, Thomas E.; Kinard, Joseph R.; Novotny, Donald B.; Sims, June E.

    2013-06-01

    We report on advances in ac voltage metrology made possible by a new generation of Multijunction Thermal Converters (MJTCs). Although intended for use primarily in high-frequency (1 MHz to 100 MHz) metrology, their exceptional low-frequency qualities, combined with a large dynamic range, makes these MJTCs excellent devices for the frequency range 10 Hz to 100 MHz at voltages from 1 V to 20 V, depending on the design. We anticipate that these devices will form the future basis for ac voltage metrology at the National Institute of Standards and Technology (NIST).

  10. L’acétaminophène chez les enfants

    PubMed Central

    Goldman, Ran D.

    2013-01-01

    Résumé Question Je suggère fréquemment aux parents d’utiliser de l’acétaminophène comme traitement de la fièvre et de la douleur pour leurs enfants. J’ai récemment reçu un enfant à mon cabinet qui s’est présenté avec une éruption cutanée sous forme de lésions en cibles une journée après avoir pris de l’acétaminophène. L’éruption s’est résorbée 3 jours après qu’on ait arrêté l’administration d’acétaminophène. L’acétaminophène comporte-t-elle des risques d’événements indésirables comme celui-ci? Réponse Comme les autres médicaments ou substances actives, les préparations d’acétaminophène pourraient poser des risques d’événements indésirables. Au cours des dernières années, on a procédé à une investigation concernant une association potentielle entre l’acétaminophène et l’asthme et la Food and Drug Administration des États-Unis a récemment publié un avertissement à propos de réactions cutanées éventuelles, graves mais rares, associées à l’acétaminophène. Même si l’acétaminophène est principalement un médicament sûr, les professionnels de la santé devraient être alertes et informer les parents à propos de la possibilité d’événements indésirables rares mais sévères.

  11. 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.

  12. Microfluidic pumping optimization in microgrooved channels with ac electrothermal actuations

    NASA Astrophysics Data System (ADS)

    Du, E.; Manoochehri, Souran

    2010-01-01

    An optimization methodology is developed and applied to an ac electrothermal pump design with patterned microgrooved features. The microgrooved configuration can overcome the restrictions of the conventional planar configuration on pumping performance by diminishing fast backward flows and suppressing prolonged streamlines. At all frequency excitations (0.2-1000 MHz) and ion concentration conditions (5×10-3-0.1 M), the optimum microgrooved configuration generates much faster flow rate than planar configuration. This happens without additional increases in the maximum temperature values. The effects of elevated temperature on ac ET flow behavior is investigated and analyzed.

  13. AC and Phase Sensing of Nanowires for Biosensing.

    PubMed

    Crescentini, Marco; Rossi, Michele; Ashburn, Peter; Lombardini, Marta; Sangiorgi, Enrico; Morgan, Hywel; Tartagni, Marco

    2016-04-19

    Silicon nanowires are label-free sensors that allow real-time measurements. They are economical and pave the road for point-of-care applications but require complex readout and skilled personnel. We propose a new model and technique for sensing nanowire sensors using alternating currents (AC) to capture both magnitude and phase information from the sensor. This approach combines the advantages of complex impedance spectroscopy with the noise reduction performances of lock-in techniques. Experimental results show how modifications of the sensors with different surface chemistries lead to the same direct-current (DC) response but can be discerned using the AC approach.

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

    SciTech Connect

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

    2008-07-08

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

  15. The ac propulsion system for an electric vehicle, phase 1

    NASA Technical Reports Server (NTRS)

    Geppert, S.

    1981-01-01

    A functional prototype of an electric vehicle ac propulsion system was built consisting of a 18.65 kW rated ac induction traction motor, pulse width modulated (PWM) transistorized inverter, two speed mechanically shifted automatic transmission, and an overall drive/vehicle controller. Design developmental steps, and test results of individual components and the complex system on an instrumented test frame are described. Computer models were developed for the inverter, motor and a representative vehicle. A preliminary reliability model and failure modes effects analysis are given.

  16. Interplay between electron overheating and ac Josephson effect

    NASA Astrophysics Data System (ADS)

    De Cecco, A.; Le Calvez, K.; Sacépé, B.; Winkelmann, C. B.; Courtois, H.

    2016-05-01

    We study the response of high-critical-current proximity Josephson junctions to a microwave excitation. Electron overheating in such devices is known to create hysteretic dc voltage-current characteristics. Here we demonstrate that it also strongly influences the ac response. The interplay of electron overheating and ac Josephson dynamics is revealed by the evolution of the Shapiro steps with the microwave drive amplitude. Extending the resistively shunted Josephson junction model by including a thermal balance for the electronic bath coupled to phonons, a strong electron overheating is obtained.

  17. Trapping of Rb Atoms by ac Electric Fields

    SciTech Connect

    Schlunk, Sophie; Marian, Adela; Geng, Peter; Meijer, Gerard; Schoellkopf, Wieland; Mosk, Allard P.

    2007-06-01

    We demonstrate trapping of an ultracold gas of neutral atoms in a macroscopic ac electric trap. Three-dimensional confinement is obtained by switching between two saddle-point configurations of the electric field. Stable trapping is observed in a narrow range of switching frequencies around 60 Hz. The dynamic confinement of the atoms is directly visualized at different phases of the ac switching cycle. We observe about 10{sup 5} Rb atoms in the 1 mm{sup 3} large and several microkelvins deep trap with a lifetime of approximately 5 s.

  18. AC and Phase Sensing of Nanowires for Biosensing

    PubMed Central

    Crescentini, Marco; Rossi, Michele; Ashburn, Peter; Lombardini, Marta; Sangiorgi, Enrico; Morgan, Hywel; Tartagni, Marco

    2016-01-01

    Silicon nanowires are label-free sensors that allow real-time measurements. They are economical and pave the road for point-of-care applications but require complex readout and skilled personnel. We propose a new model and technique for sensing nanowire sensors using alternating currents (AC) to capture both magnitude and phase information from the sensor. This approach combines the advantages of complex impedance spectroscopy with the noise reduction performances of lock-in techniques. Experimental results show how modifications of the sensors with different surface chemistries lead to the same direct-current (DC) response but can be discerned using the AC approach. PMID:27104577

  19. Introducing AC inductive reactance with a power tool

    NASA Astrophysics Data System (ADS)

    Bryant, Wesley; Baker, Blane

    2016-09-01

    The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance is smaller than expected, they are asked to explain these observations using previously studied principles of magnetic induction. Exercises also introduce the notion of inductive reactance and impedance in AC circuits and, ultimately, determine self-inductance of the motor windings within the power tool.

  20. Dynamically tuned high-Q AC-dipole implementation

    SciTech Connect

    Oddo, P.; Bai, M.; Dawson, W.C.; Meng, W.; Mernick, K.; Pai, C.; Roser, T.; Russo, T.

    2010-05-02

    AC-dipole magnets are typically implemented as a parallel LC resonant circuit. To maximize efficiency, it's beneficial to operate at a high Q. This, however, limits the magnet to a narrow frequency range. Current designs therefore operate at a low Q to provide a wider bandwidth at the cost of efficiency. Dynamically tuning a high Q resonant circuit tries to maintain a high efficiency while providing a wide frequency range. The results of ongoing efforts at BNL to implement dynamically tuned high-Q AC dipoles will be presented.

  1. 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.

  2. System and method for determining stator winding resistance in an AC motor using motor drives

    DOEpatents

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

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

    PubMed Central

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

    2016-01-01

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

  4. UPS with input commutation between ac and dc sources of power

    SciTech Connect

    Severinsky, A.J.

    1993-08-31

    An uninterruptible power supply is described, said power supply comprising: AC input terminal means for receiving a first AC voltage from an AC power source; DC input terminal means for receiving a first DC voltage from a DC power source; AC output terminal means for connecting to a load; converter means for converting said first AC voltage to a second DC voltage across electrical charge storage means coupled to said converter means, said second DC voltage being larger than the maximum peak voltage of said first AC voltage and said first DC voltage; switching means coupled to said AC power source and said DC power source for selectively connecting said AC power source or said DC power source to said converter means; inverter means coupled to said electrical charge storage means for receiving said second DC voltage and inverting said second DC voltage to a second AC voltage, said second AC voltage being coupled to said AC output terminal means; and control means coupled to said switching means for controlling the operation of said switching means, said control means operating said switching means to connect said AC power source to said converter means only when said first AC voltage is within a predetermined range and operating to connect said DC power source to said converter means when said first AC voltage is outside of said range.

  5. Cloning of the Aegiceras corniculatum class I chitinase gene (AcCHI I) and the response of AcCHI I mRNA expression to cadmium stress.

    PubMed

    Wang, Li-Ying; Wang, You-Shao; Cheng, Hao; Zhang, Jing-Ping; Yeok, Foong Swee

    2015-10-01

    Chitinases in terrestrial plants have been reported these are involved in heavy metal tolerance/detoxification. This is the first attempt to reveal chitinase gene (AcCHI I) and its function on metal detoxification in mangroves Aegiceras corniculatum. RT-PCR and RACE techniques were used to clone AcCHI I, while real-time quantitative PCR was employed to assess AcCHI I mRNA expressions in response to Cadmium (Cd). The deduced AcCHI I protein consists of 316 amino acids, including a signal peptide region, a chitin-binding domain (CBD) and a catalytic domain. Protein homology modeling was performed to identify potential features in AcCHI I. The CBD structure of AcCHI I might be critical for metal tolerance/homeostasis of the plant. Clear tissue-specific differences in AcCHI I expression were detected, with higher transcript levels detected in leaves. Results demonstrated that a short duration of Cd exposure (e.g., 3 days) promoted AcCHI I expression in roots. Upregulated expression was also detected in leaves under 10 mg/kg Cd concentration stress. The present study demonstrates that AcCHI I may play an important role in Cd tolerance/homeostasis in the plant. Further studies of the AcCHI I protein, gene overexpression, the promoter and upstream regulation will be necessary for clarifying the functions of AcCHI I. PMID:26044931

  6. Cloning of the Aegiceras corniculatum class I chitinase gene (AcCHI I) and the response of AcCHI I mRNA expression to cadmium stress.

    PubMed

    Wang, Li-Ying; Wang, You-Shao; Cheng, Hao; Zhang, Jing-Ping; Yeok, Foong Swee

    2015-10-01

    Chitinases in terrestrial plants have been reported these are involved in heavy metal tolerance/detoxification. This is the first attempt to reveal chitinase gene (AcCHI I) and its function on metal detoxification in mangroves Aegiceras corniculatum. RT-PCR and RACE techniques were used to clone AcCHI I, while real-time quantitative PCR was employed to assess AcCHI I mRNA expressions in response to Cadmium (Cd). The deduced AcCHI I protein consists of 316 amino acids, including a signal peptide region, a chitin-binding domain (CBD) and a catalytic domain. Protein homology modeling was performed to identify potential features in AcCHI I. The CBD structure of AcCHI I might be critical for metal tolerance/homeostasis of the plant. Clear tissue-specific differences in AcCHI I expression were detected, with higher transcript levels detected in leaves. Results demonstrated that a short duration of Cd exposure (e.g., 3 days) promoted AcCHI I expression in roots. Upregulated expression was also detected in leaves under 10 mg/kg Cd concentration stress. The present study demonstrates that AcCHI I may play an important role in Cd tolerance/homeostasis in the plant. Further studies of the AcCHI I protein, gene overexpression, the promoter and upstream regulation will be necessary for clarifying the functions of AcCHI I.

  7. BOLD signal effects of transcranial alternating current stimulation (tACS) in the alpha range: A concurrent tACS-fMRI study.

    PubMed

    Vosskuhl, Johannes; Huster, René J; Herrmann, Christoph S

    2016-10-15

    Many studies have proven transcranial alternating current stimulation (tACS) to manipulate brain activity. Until now it is not known, however, how these manipulations in brain activity are represented in brain metabolism or how spatially specific these changes are. Alpha-tACS has been shown to enhance the amplitude of the individual alpha frequency (IAF) and a negative correlation between alpha amplitude and occipital BOLD signal was reported in numerous EEG/fMRI experiments. Thus, alpha-tACS was chosen to test the effects of tACS on the BOLD signal. A reduction thereof was expected during alpha-tACS which shows the spatial extent of tACS effects beyond modeling studies. Three groups of subjects were measured in an MRI scanner, receiving tACS at either their IAF (N=11), 1Hz (control; N=12) or sham (i.e., no stimulation - a second control; N=11) while responding to a visual vigilance task. Stimulation was administered in an interleaved pattern of tACS-on runs and tACS-free baseline periods. The BOLD signal was analyzed in response to tACS-onset during resting state and in response to seldom target stimuli. Alpha-tACS at 1.0mA reduced the task-related BOLD response to visual targets in the occipital cortex as compared to tACS-free baseline periods. The deactivation was strongest in an area where the BOLD signal was shown to correlate negatively with alpha amplitude. A direct effect of tACS on resting state BOLD signal levels could not be shown. Our findings suggest that tACS-related changes in BOLD activity occur only as a modulation of an existing BOLD response.

  8. 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

  9. 78 FR 42567 - ACS Wireless, Inc.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-16

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION ACS Wireless, Inc.; Notice of Application June 25, 2013. Correction In notice document 2013-15658 beginning on page 39345 in the issue of Monday, July 1, 2013, make the following correction: On page...

  10. Introducing AC Inductive Reactance with a Power Tool

    ERIC Educational Resources Information Center

    Bryant, Wesley; Baker, Blane

    2016-01-01

    The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance…

  11. An overview of the ALMA Common Software (ACS) .

    NASA Astrophysics Data System (ADS)

    Di Marcantonio, P.; Cirami, R.; Caproni, A.; Chiozzi, G.; Jeram, B.; Sommer, H.; Harrington, S.; Zagar, K.; Plesko, M.; Sekoranja, M.

    The ALMA Common Software (ACS) is an application framework designed to provide a common and homogeneous software architecture and infrastructure, spanning the end to end needs of an Astronomical observatory, from the Telescope Control system to high-level data flow management. ACS offers, at the lower level, several basic services needed for object-oriented distributed computing like transparent remote object invocation, object deployment and location, distributed error, alarm handling, logging and events. On top of this it provides an application architecture based on the Component/Container paradigm that fosters sharing and reusing of software components. Although developed for the ALMA project, ACS is now used by several other projects worldwide, among which the Italian Sardinia Radio Telescope (SRT). Besides, there is an active community that shares ideas, concepts and actual software components. Major drivers for this diffusion were the choice of adopting the LGPL public license and the adoption of CORBA, a free but reliable and widely used middleware software. In this paper we present an overview of the main features of ACS, emphasizing in particular the role of INAF-OAT in this project.

  12. Container-component model and XML in ALMA ACS

    NASA Astrophysics Data System (ADS)

    Sommer, Heiko; Chiozzi, Gianluca; Zagar, Klemen; Voelter, Markus

    2004-09-01

    ALMA software, from high-level data flow applications down to instrument control, is built using the ACS framework. To meet the challenges of developing distributed software in distributed teams, ACS offers a container/component model that integrates the use of XML transfer objects. ACS containers are built on top of CORBA and are available for C++, Java, and Python, so that ALMA software can be written as components in any of these languages. The containers perform technical aspects of the software system, while components can focus on the implementation of functional requirements. Like Web services, components can use XML to exchange structured data by value. For Java components, the container seamlessly integrates the use of XML binding classes, which are Java classes that encapsulate access to XML data through type-safe methods. Binding classes are generated from XML schemas, allowing the Java compiler to enforce compliance of application code with the XML schemas. This presentation will explain the capabilities of the ACS container/component model, and how it relates to other middleware technologies that are popular in industry.

  13. Measurement of the 225Ac half-life.

    PubMed

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

    2012-11-01

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

  14. Regenerating /sup 227/Ac from highly contaminated preparations

    SciTech Connect

    Volynskii, L.D.; Garbuzov, V.M.; Tsirlin, V.A.

    1988-05-01

    Studies have been made on the conditions for coprecipitation of actinium with calcium, barium, and iron fluorides, as well as on the conditions for the selective separation of actinium and iron on a cation-exchange material by the use of hydrochloric acid in acetone. Several ways of regenerating /sup 337/Ac from highly contaminated preparations are proposed.

  15. 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.

  16. High-power ac/dc variable load simulator

    NASA Technical Reports Server (NTRS)

    Joncas, K. P.; Birnbach, S.; Bruce, L. D.; Smith, L.

    1975-01-01

    Design of medium-power dynamic electrical load simulator has been extended to permit simulation of ac as well as dc loads and to provide for operation at higher power levels. Simulator is internally protected against reverse voltage, overvoltage, overcurrent, and overload conditions.

  17. Measurement of the 225Ac half-life.

    PubMed

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

    2012-11-01

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

  18. 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.

  19. 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

  20. Equivalent Circuits For AC-Impedance Analysis Of Corrosion

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1992-01-01

    Report presents investigation of equivalent circuits for ac-impedance analysis of corrosion. Impedance between specimen and electrolyte measured as function of frequency. Data used to characterize corrosion electrochemical system in terms of equivalent circuit. Eleven resistor/capacitor equivalent-circuit models were analyzed.

  1. Direct Experimental Observation of a Practical AC Zeeman Force

    NASA Astrophysics Data System (ADS)

    Fancher, Charles; Pyle, Andrew; Rotunno, Andrew; Du, Shuangli; Aubin, Seth

    2016-05-01

    We present measurements of the spin-dependent AC Zeeman force produced by microwave magnetic near-field gradients on an atom chip. We measure the AC Zeeman force on ultracold 87 Rb atoms by observing its effect on the motion of atoms in free-fall and on those confined in a trap. We have studied the force as a function of microwave frequency detuning from a hyperfine transition at 6.8 GHz at several magnetic field strengths and have observed its characteristic bipolar and resonant features predicted by two-level dressed atom theory. We find that the force is several times the strength of gravity in our setup, and that it can be targeted to a specific hyperfine transition while leaving other hyperfine states and transitions relatively unaffected. We find that our measurements are reasonably consistent with theory and are working towards a parameter-free comparison. AC Zeeman potentials offer the possibility of targeting qualitatively different trapping potentials to different spin states, a capability currently absent from the toolbox of atomic quantum control techniques. In particular, an AC Zeeman potential could be used as the beamsplitter for a spin-dependent atom interferometer or for engineering a quantum gate. Work supported by AFOSR and W&M, and in part by AFRL.

  2. 23. AC GENERATOR, ALLISCHALMERS SN #1246797, MFG. MILWAUKEE, KW 1600 ...

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

    23. AC GENERATOR, ALLIS-CHALMERS SN #1246797, MFG. MILWAUKEE, KW 1600 PF 80 C/O VOLTS 2300 AMPS 503 CY 60 PH 3 RMP 164 EXC VOLTS 125 AMPS MAN 300 - Columbia Canal & Power Plant, Waterfront of Broad River, Columbia, Richland County, SC

  3. Power factor control system for AC induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1977-01-01

    A power factor control system for use with ac induction motors was designed which samples lines voltage and current through the motor and decreases power input to the motor proportional to the detected phase displacement between current and voltage. This system provides, less power to the motor, as it is less loaded.

  4. Context based computational analysis and characterization of ARS consensus sequences (ACS) of Saccharomyces cerevisiae genome.

    PubMed

    Singh, Vinod Kumar; Krishnamachari, Annangarachari

    2016-09-01

    Genome-wide experimental studies in Saccharomyces cerevisiae reveal that autonomous replicating sequence (ARS) requires an essential consensus sequence (ACS) for replication activity. Computational studies identified thousands of ACS like patterns in the genome. However, only a few hundreds of these sites act as replicating sites and the rest are considered as dormant or evolving sites. In a bid to understand the sequence makeup of replication sites, a content and context-based analysis was performed on a set of replicating ACS sequences that binds to origin-recognition complex (ORC) denoted as ORC-ACS and non-replicating ACS sequences (nrACS), that are not bound by ORC. In this study, DNA properties such as base composition, correlation, sequence dependent thermodynamic and DNA structural profiles, and their positions have been considered for characterizing ORC-ACS and nrACS. Analysis reveals that ORC-ACS depict marked differences in nucleotide composition and context features in its vicinity compared to nrACS. Interestingly, an A-rich motif was also discovered in ORC-ACS sequences within its nucleosome-free region. Profound changes in the conformational features, such as DNA helical twist, inclination angle and stacking energy between ORC-ACS and nrACS were observed. Distribution of ACS motifs in the non-coding segments points to the locations of ORC-ACS which are found far away from the adjacent gene start position compared to nrACS thereby enabling an accessible environment for ORC-proteins. Our attempt is novel in considering the contextual view of ACS and its flanking region along with nucleosome positioning in the S. cerevisiae genome and may be useful for any computational prediction scheme. PMID:27508123

  5. Biocontrol activity of Paenibacillus polymyxa AC-1 against Pseudomonas syringae and its interaction with Arabidopsis thaliana.

    PubMed

    Hong, Chi Eun; Kwon, Suk Yoon; Park, Jeong Mee

    2016-04-01

    Paenibacillus polymyxa AC-1 (AC-1) is a plant growth-promoting rhizobacterium (PGPR) that has been used as a soil inoculant for biocontrol of plant pathogenic fungi and to promote plant growth. In this study, we examine the effects of AC-1 on the bacterial phytopathogen Pseudomonas syringae and internal colonization of AC-1 by counting bacterial populations that colonize plants. AC-1 inhibited the growth of both P. syringae pv. tomato DC3000 (Pst) and P. syringae pv. tabaci (Pta) in a concentration-dependent manner in in vitro assays. Upon treatment of AC-1 dropping at root tip of axenically grown Arabidopsis, we found that most of the AC-1 was detected in interior of leaves of Arabidiopsis plants rather than roots after 5 days post infection, indicating systemic spreading of AC-1 occur. We examined further AC-1 colonization patterns in Arabidopsis mutants deficient in phytohormone signaling pathways. These results indicated that abscisic acid (ABA) and jasmonic acid (JA) signaling pathways positively and negatively contributed, respectively, to AC-1 colonization of leaves, whereas epiphytic accumulation of AC-1 around root tissues was not affected. This study shows that AC-1 is an effective biocontrol agent to suppress P. syringae growth, possibly owing to its colonization patterns as a leaf-inhabiting endophyte. The results showed in this work will help to expand our understanding of the mode of action of AC-1 as a biological control agent and consequently, its application in agriculture.

  6. Autographa californica multiple nucleopolyhedrovirus gene ac81 is required for nucleocapsid envelopment.

    PubMed

    Dong, Fang; Wang, Jinwen; Deng, Riqiang; Wang, Xunzhang

    2016-08-01

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly pathogenic Baculoviridae that targets insects, whose core gene, ac81, has an unknown function. To determine the role of ac81 in the life cycle of AcMNPV, an ac81-knockout (Ac-81KO-GP) was constructed through homologous recombination in Escherichia coli. We determined that no budded virions were produced in Ac-81KO-GP-transfected Sf9 cells, while there was no effect on viral DNA replication. Electron microscopy (EM) analysis revealed that occlusion-derived virions (ODVs) envelopment and the subsequent embedding of virions into occlusion bodies (OBs) were aborted due to ac81 deletion. Interestingly, confocal microscopy and immunofluorescence analysis revealed that Ac81 was predominantly localized to the ring zone of nuclei during the late phase of infection. In addition, Ac81 was localized to the mature and premature ODVs in virus-infected cells within the ring zone as revealed by immuno-electron microscopy (IEM) analysis. Furthermore, we determined that Ac81 contained a functional hydrophobic transmembrane (TM) domain, whose deletion resulted in a phenotype similar to that of Ac-81KO-GP. These results suggest that Ac81 might be a TM protein that played an important role in nucleocapsid envelopment. PMID:27212683

  7. 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.

  8. Expression characteristics of CS-ACS1, CS-ACS2 and CS-ACS3, three members of the 1-aminocyclopropane-1-carboxylate synthase gene family in cucumber (Cucumis sativus L.) fruit under carbon dioxide stress.

    PubMed

    Mathooko, F M; Mwaniki, M W; Nakatsuka, A; Shiomi, S; Kubo, Y; Inaba, A; Nakamura, R

    1999-02-01

    We investigated the expression pattern of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes, CS-ACS1, CS-ACS2 and CS-ACS3 in cucumber (Cucumis sativus L.) fruit under CO2 stress. CO2 stress-induced ethylene production paralleled the accumulation of only CS-ACS1 transcripts which disappeared upon withdrawal of CO2. Cycloheximide inhibited the CO2 stress-induced ethylene production but superinduced the accumulation of CS-ACS1 transcript. At higher concentrations, cycloheximide also induced the accumulation of CS-ACS2 and CS-ACS3 transcripts. In the presence of CO2 and cycloheximide, the accumulation of CS-ACS2 transcript occurred within 1 h, disappeared after 3 h and increased greatly upon withdrawal of CO2. Inhibitors of protein kinase and types 1 and 2A protein phosphatases which inhibited and stimulated, respectively, CO2 stress-induced ethylene production had little effect on the expression of these genes. The results presented here identify CS-ACS1 as the main ACC synthase gene responsible for the increased ethylene biosynthesis in cucumber fruit under CO2 stress and suggest that this gene is a primary response gene and its expression is under negative control since it is expressed by treatment with cycloheximide. The results further suggest that the regulation of CO2 stress-induced ethylene biosynthesis by reversible protein phosphorylation does not result from enhanced ACC synthase transcription. PMID:10202812

  9. Recent applications of AC electrokinetics in biomolecular analysis on microfluidic devices.

    PubMed

    Sasaki, Naoki

    2012-01-01

    AC electrokinetics is a generic term that refers to an induced motion of particles and fluids under nonuniform AC electric fields. The AC electric fields are formed by application of AC voltages to microelectrodes, which can be easily integrated into microfluidic devices by standard microfabrication techniques. Moreover, the magnitude of the motion is large enough to control the mass transfer on the devices. These advantages are attractive for biomolecular analysis on the microfluidic devices, in which the characteristics of small space and microfluidics have been mainly employed. In this review, I describe recent applications of AC electrokinetics in biomolecular analysis on microfluidic devices. The applications include fluid pumping and mixing by AC electrokinetic flow, and manipulation of biomolecules such as DNA and proteins by various AC electrokinetic techniques. Future prospects for highly functional biomolecular analysis on microfluidic devices with the aid of AC electrokinetics are also discussed.

  10. Autographa californica multiple nucleopolyhedrovirus ac53 plays a role in nucleocapsid assembly

    SciTech Connect

    Liu Chao; Li Zhaofei Wu Wenbi; Li Lingling; Yuan Meijin; Pan Lijing; Yang Kai Pang Yi

    2008-12-05

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf53 (ac53) is a highly conserved gene existing in all sequenced Lepidoptera and Hymenoptera baculoviruses, but its function remains unknown. To investigate its role in the baculovirus life cycle, an ac53 deletion virus (vAc{sup ac53KO-PH-GFP}) was generated through homologous recombination in Escherichia coli. Fluorescence and light microscopy and titration analysis revealed that vAc{sup ac53KO-PH-GFP} could not produce infectious budded virus in infected Sf9 cells. Real-time PCR demonstrated that the ac53 deletion did not affect the levels of viral DNA replication. Electron microscopy showed that many lucent tubular shells devoid of the nucleoprotein core are present in the virogenic stroma and ring zone, indicating that the ac53 knockout affected nucleocapsid assembly. With a recombinant virus expressing an Ac53-GFP fusion protein, we observed that Ac53 was distributed within the cytoplasm and nucleus at 24 h post-infection, but afterwards accumulated predominantly near the nucleus-cytoplasm boundary. These data demonstrate that ac53 is involved in nucleocapsid assembly and is an essential gene for virus production.

  11. Software Development for ALMA in Chile: The ACS-UTFSM Group.

    NASA Astrophysics Data System (ADS)

    von Brand, H. H.

    ALMA Common Software (ACS) provides a common software framework for ALMA, the Atacama Large Millimeter Array in Chile. ACS is a collection of well-documented patterns for controlling systems and a set of components written to those patterns. In its core, ACS is a distributed, object-oriented system, written on top of CORBA. The ACS-UTFSM Group started as some students of informatics did summer jobs at the La Silla Observatory of ESO, where they became acquainted with ACS. Their interest led them to continue working on ACS on their own, and they eventually became official developers of the package. Now the group is being funded by project ALMA-CONICYT 31060008 ``Software Development for ALMA: Building Up Expertise to Meet ALMA Software Requirements within a Chilean University''. Several members of the original group are now working for ALMA, which fullfills one of the goals of the project. Some parts of ACS developed by the ACS-UTFSM Group include H3E (Hardware End-to-End Example), a Lego model of a telescope and its controlling software for training and demonstration purposes; and CDBChecker, a tool to verify the consistency of the configuration database for a ACS deployment. Currently we are working towards a general framework for telescope control using ACS, in order to simplify the deployment of new instruments; and repackaging ACS so it is easier to install and use. A master's thesis is exploring the real-time requirements of ACS.

  12. 21 CFR 880.5510 - Non-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 Non-AC-powered patient lift. 880.5510 Section 880.5510 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is...

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

    SciTech Connect

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

    2008-01-31

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

  14. Autographa californica multiple nucleopolyhedrovirus ac76 is involved in intranuclear microvesicle formation.

    PubMed

    Hu, Zhaoyang; Yuan, Meijin; Wu, Wenbi; Liu, Chao; Yang, Kai; Pang, Yi

    2010-08-01

    In this study, we characterized Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf76 (ac76), which is a highly conserved gene of unknown function in lepidopteran baculoviruses. Transcriptional analysis of ac76 revealed that transcription of multiple overlapping multicistronic transcripts initiates from a canonical TAAG late-transcription start motif but terminates at different 3' ends at 24 h postinfection in AcMNPV-infected Sf9 cells. To investigate the role of ac76 in the baculovirus life cycle, an ac76-knockout virus was constructed using an AcMNPV bacmid system. Microscopy, titration assays, and Western blot analysis demonstrated that the resulting ac76-knockout virus was unable to produce budded viruses. Quantitative real-time PCR analysis demonstrated that ac76 deletion did not affect viral DNA synthesis. Electron microscopy showed that virus-induced intranuclear microvesicles as well as occlusion-derived virions were never observed in cells transfected with the ac76-knockout virus. Confocal microscopy analysis revealed that Ac76 was predominantly localized to the ring zone of nuclei during the late phase of infection. This suggests that ac76 plays a role in intranuclear microvesicle formation. To the best of our knowledge, this is the first baculovirus gene identified to be involved in intranuclear microvesicle formation.

  15. Autographa californica multiple nucleopolyhedrovirus ac53 plays a role in nucleocapsid assembly.

    PubMed

    Liu, Chao; Li, Zhaofei; Wu, Wenbi; Li, Lingling; Yuan, Meijin; Pan, Lijing; Yang, Kai; Pang, Yi

    2008-12-01

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf53 (ac53) is a highly conserved gene existing in all sequenced Lepidoptera and Hymenoptera baculoviruses, but its function remains unknown. To investigate its role in the baculovirus life cycle, an ac53 deletion virus (vAc(ac53KO-PH-GFP)) was generated through homologous recombination in Escherichia coli. Fluorescence and light microscopy and titration analysis revealed that vAc(ac53KO-PH-GFP) could not produce infectious budded virus in infected Sf9 cells. Real-time PCR demonstrated that the ac53 deletion did not affect the levels of viral DNA replication. Electron microscopy showed that many lucent tubular shells devoid of the nucleoprotein core are present in the virogenic stroma and ring zone, indicating that the ac53 knockout affected nucleocapsid assembly. With a recombinant virus expressing an Ac53-GFP fusion protein, we observed that Ac53 was distributed within the cytoplasm and nucleus at 24 h post-infection, but afterwards accumulated predominantly near the nucleus-cytoplasm boundary. These data demonstrate that ac53 is involved in nucleocapsid assembly and is an essential gene for virus production.

  16. 21 CFR 880.5510 - Non-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 Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport...

  17. 21 CFR 880.5510 - Non-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 Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport...

  18. 21 CFR 880.5510 - Non-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 Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport...

  19. 21 CFR 880.5510 - Non-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 Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport...

  20. Examining the Effects of Introducing Online Access to ACS Journals at Primarily Undergraduate Institutions

    ERIC Educational Resources Information Center

    Landolt, R. G.

    2007-01-01

    In collaboration with the Publications Division of the American Chemical Society (ACS), students and faculty at 24 primarily undergraduate institutions were provided online access to ACS primary research journals for a period of 18 months, and a group of eight schools were granted access to use the archives of ACS journals for a year. Resources…

  1. AcMNPV Core Gene ac109 Is Required for Budded Virion Transport to the Nucleus and for Occlusion of Viral Progeny

    PubMed Central

    Alfonso, Victoria; Maroniche, Guillermo A.; Reca, Sol R.; López, María Gabriela; del Vas, Mariana; Taboga, Oscar

    2012-01-01

    The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac109 core gene has been previously characterized as an essential late gene. Our results showed that budded virions could be detected in supernatants of infected Sf-9 cells, even when ac109 knockout viruses displayed a single-cell infection phenotype. Moreover, confocal microscopy analysis revealed that budded virions can enter the cytoplasm but are unable to enter the cell nucleus. This defect could be repaired by complementing ac109 in trans. In addition, polyhedra of normal size could be detected in Sf-9 nuclei infected with ac109 knockout viruses. However, electron microscopy demonstrated that these occlusion bodies were empty. Altogether, these results indicate that ac109 is required for infectivity of both phenotypes of virus. PMID:23049963

  2. Characterization of an Ac transposon system based on apt1-m1 (Ac) on the long arm of maize chromosome 9.

    PubMed

    Wang, Fei; Li, Pengfei; Tang, Yuanping; Fan, Jun; Xu, Dabin; Guo, Shengming; Xu, Zhengkai; Song, Rentao

    2012-09-01

    Activator/Dissociation (Ac/Ds) transposable elements have been used in maize insertional mutagenesis as a complement to Mutator (Mu). In this study, to further improve the efficiency of the Ac/Ds mutagenesis system, we adopted apt1-m1 (Ac) on the long arm of chromosome 9 (9L) as a donor Ac to create an Ac insertion library. This system is based on the negative selection pressure against the donor Ac, and it was highly efficient for isolating new transposition events. We obtained 9,625 transposition events from 1083 F1 ears with an average transposition rate of 8.66 % (rates ranged from 1.11 to 29.73 %). We also adopted a modified PCR-based genome walking strategy to improve the efficiency of the new method for isolating transposon-flanking sequences. This method is more efficient than the Southern-based method that was used in previous studies. A validation step was developed to distinguish transposon tags derived from newly transposed Ac or Ds elements. Using this PCR-based method, we isolated 67 inheritable flanking sequences from the apt1-m1 (Ac) transposition library; of these, 51 were confirmed as tr-Ac-flanking sequences and 11 were tr-Ds-flanking sequences. Similar to other Ac donors from different loci, the apt1-m1 (Ac) system also exhibited a preference for short distance transposition. In this study, we have further improved the Ac mutagenesis system in maize for gene isolation and functional genomics studies.

  3. Characterization of flow-through electrode processes by AC impedance

    SciTech Connect

    Yuh, C.Y. ); Selman, J.R. )

    1993-04-01

    Flow-through porous electrodes, such as packed-bed and fluidized-bed electrodes, are attractive for electrowinning, electro-organic synthesis and flow-battery applications. The extensive surface area of the porous electrodes makes high volumetric reaction rate more possible than in a cell with smooth electrodes. Forced convection also enhances mass-transfer rate and hence reduces concentration polarization. AC-impedance method has been used successfully in characterizing a packed-bed flow-through electrode system. A macrohomogeneous model was developed to simulate the effect of structural, physical and flow parameters. The relative importance of kinetics and mass transfer can be inferred from the AC-impedance analysis. Kinetic information about copper deposition in supported cupric sulfate solution has been obtained successfully using this technique.

  4. AC operation and runaway electron behaviour in HT-7 tokamak

    NASA Astrophysics Data System (ADS)

    Lu, Hong-Wei; Hu, Li-Qun; Zhou, Rui-Jie; Lin, Shi-Yao; Zhong, Guo-Qiang; Wang, Shao-Feng; Chen, Kai-Yun; Xu, Ping; Zhang, Ji-Zong; Ling, Bi-Li; Mao, Song-Tao; Duan, Yan-Min

    2010-06-01

    Operation of HT-7 tokamak in a multicycle alternating square wave plasma current regime is reported. A set of AC operation experiments, including LHW heating to enhance plasma ionization during the current transition and current sustainment, is described. The behaviour of runaway electrons is analysed by four HXR detectors tangentially viewing the plasma in the equatorial plane, within energy ranges 0.3-1.2 MeV and 0.3-7 MeV, separately. High energy runaway electrons (~MeV) are found to circulate predominantly in the opposite direction to the plasma current, while the number of low energy runaway electrons (~tens to hundreds of keV) circulating along the plasma current is comparable to that in the direction opposite to the plasma current. AC operation with lower hybrid current drive (LHCD) is observed to have an additional benefit of suppressing the runaway electrons if the drop of the loop voltage is large enough.

  5. Towards an AC-MOT of CaF

    NASA Astrophysics Data System (ADS)

    Anderegg, Loic; Chae, Eunmi; Ravi, Aakash; Augenbraun, Benjamin; Hemmerling, Boerge; Drayna, Garrett; Hutzler, Nicholas; Collopy, Alejandra; Wu, Yewei; Ding, Shiqian; Ye, Jun; Ketterle, Wolfgang; Doyle, John

    2016-05-01

    Ultra-cold diatomic molecules have rich prospects as candidates to study controlled ultra-cold chemistry, strongly correlated systems and precision measurements. They are also considered as possible qubits in quantum computing and simulation schemes. We report on progress towards loading CaF into a molecular magneto-optical trap (MOT). An AC-MOT will be used to actively remix magnetic dark states via both polarization and magnetic field switching. In order to load a molecular MOT, we have successfully laser slowed a CaF beam to near the expected capture velocity. We describe our AC-MOT apparatus, which is designed to co-trap CaF and Li. We outline our planned study of CaF-Li collisions to explore the feasibility of sympathetically cooling molecules to ultra-cold temperatures.

  6. Final Report for the Advanced Camera for Surveys (ACS)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    ACS was launched aboard the Space Shuttle Columbia just before dawn on March 1, 2002. At the time of liftoff, the Hubble Space Telescope (HST) was reflecting the early morning sun as it moved across the sky. After successfully docking with HST, several components were replaced. One of the components was the Advanced Camera for Surveys built by Ball Aerospace & Technologies Corp. (BATC) in Boulder, Colorado. Over the life of the HST contract at BATC, hundreds of employees had the pleasure of working on the concept, design, fabrication, assembly, and test of ACS. Those employees thank NASA - Goddard Space Flight Center and the science team at Johns Hopkins University (JHU) for the opportunity to participate in building a great science instrument for HST.

  7. ac power control in the Core Flow Test Loop

    SciTech Connect

    McDonald, D.W.

    1980-01-01

    This work represents a status report on a development effort to design an ac power controller for the Core Flow Test Loop. The Core Flow Test Loop will be an engineering test facility which will simulate the thermal environment of a gas-cooled fast-breeder reactor. The problems and limitations of using sinusoidal ac power to simulate the power generated within a nuclear reactor are addressed. The transformer-thyristor configuration chosen for the Core Flow Test Loop power supply is presented. The initial considerations, design, and analysis of a closed-loop controller prototype are detailed. The design is then analyzed for improved performance possibilities and failure modes are investigated at length. A summary of the work completed to date and a proposed outline for continued development completes the report.

  8. The Study of Porous Media with AC Electrokinetics

    NASA Astrophysics Data System (ADS)

    Pengra, David B.; Wong, Po-Zen

    1996-11-01

    Electrokinetic phenomena, which involve the coupling of fluid and electric currents, are present in many porous media systems. They arise from the presence of a space charge layer at the fluid/solid interface, and depend on characteristics of the interface and properties of the porous material. Although understood for years, electrokinetic phenomena have been typically too weak to use as an experimental probe of such systems. Recently we have shown that modern instrumentation, based on AC excitations, can be used to measure electrokinetic response in porous rock. From the measurements we derive the permeability of the rock exactly, and study other physicochemical properties. We review electrokinetic theory, describe our results for porous rock, and discuss present research using the AC techniques. Research supported by the Gas Research Institute, Contract 5090-260-1953, and National Science Foundation Grant DMR-9405672.

  9. 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.

  10. [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.

  11. Development of ac corona discharge modes at atmospheric pressure

    SciTech Connect

    El-Koramy, Reda Ahmed; Yehia, Ashraf; Omer, Mohamed

    2011-02-15

    Corona discharges in gases exist under several distinctive forms. In this paper, a survey study has been made of ac corona discharge modes generated in some different gases fed in a wire-duct reactor with a constant rate of flowing at atmospheric pressure. The properties of different corona modes are analyzed under some condition transitions from Trichel pulses to a steady glow. In the course of the presented experimental work, numerous apparent contradictions with earlier observations necessitated further study and are given to provide more information on the physical mechanisms of the ac corona discharges. Furthermore, we have gained insight into some new technologies and applications of the environmentally friendly corona and plasma discharges.

  12. Measured losses in superconductor magnets for 60-Hertz ac operation.

    NASA Technical Reports Server (NTRS)

    Hamlet, I. L.; Kilgore, R. A.

    1971-01-01

    Results of an experimental study of electrical losses in superconductor magnets. Preliminary 60-Hz ac loss data are presented for coils constructed of Nb3Sn ribbon, Nb-Ti cable, and multifilament Nb-Ti. Losses have been measured for different size coils up to approximately 20 cm in diameter. Of the conductor types tested, Nb3Sn ribbon has the lowest losses for ac operation. In Nb3Sn-ribbon coils of different sizes, the loss per unit length of conductor is shown to decrease with a decrease in the rate of change of current and to increase, in general, with increase in coil size. An important aspect of the study is the high degree of repeatability of the data.

  13. On-Chip AC self-test controller

    DOEpatents

    Flanagan, John D.; Herring, Jay R.; Lo, Tin-Chee

    2009-09-29

    A system for performing AC self-test on an integrated circuit that includes a system clock for normal operation is provided. The system includes the system clock, self-test circuitry, a first and second test register to capture and launch test data in response to a sequence of data pulses, and a logic circuit to be tested. The self-test circuitry includes an AC self-test controller and a clock splitter. The clock splitter generates the sequence of data pulses including a long data capture pulse followed by an at speed data launch pulse and an at speed data capture pulse followed by a long data launch pulse. The at speed data launch pulse and the at speed data capture pulse are generated for a common cycle of the system clock.

  14. AC Magnetic Field Frequency Dependence of Magnetoacoustic Emission

    NASA Technical Reports Server (NTRS)

    Namkung, M.; Wincheski, B.; Fulton, J. P.; DeNale, R.

    1992-01-01

    Our recent study has proved a strong correlation between the low-frequency AC applied magnetic field amplitude dependence of the asymmetry of the magnetoacoustic emission (MAE) burst and the strength of the domain wall-defect interaction in iron-base ferromagnets. For the present study the AC magnetic field frequency dependence of the asymmetry has been investigated in the range of 1 to 200 Hz. When represented by the third moment of the rectified acoustic emission pulses, the asymmetry becomes a bell-shaped function of frequency with its center located around 25 Hz. This experiment has been performed with low carbon, high yield stress steel specimens of three different levels of domain wall-defect interaction strength. The results show that the increase in the interaction strength causes a vertical down shift of the asymmetry in the entire frequency range investigated.

  15. Ac magnetic susceptibility study of in vivo nanoparticle biodistribution

    NASA Astrophysics Data System (ADS)

    Gutiérrez, L.; Mejías, R.; Barber, D. F.; Veintemillas-Verdaguer, S.; Serna, C. J.; Lázaro, F. J.; Morales, M. P.

    2011-06-01

    We analysed magnetic nanoparticle biodistribution, before and after cytokine conjugation, in a mouse model by ac susceptibility measurements of the corresponding resected tissues. Mice received repeated intravenous injections of nanoparticle suspension for two weeks and they were euthanized 1 h after the last injection. In general, only 10% of the total injected nanoparticles after multiple exposures were found in tissues. The rest of the particles may probably be metabolized or excreted by the organism. Our findings indicate that the adsorption of interferon to DMSA-coated magnetic nanoparticles changes their biodistribution, reducing the presence of nanoparticles in lungs and therefore their possible toxicity. The specific targeting of the particles to tumour tissues by the use of an external magnetic field has also been studied. Magnetic nanoparticles were observed by transmission electron microscopy in the targeted tissue and quantified by ac magnetic susceptibility.

  16. Diagnostic of water trees using DC and AC voltages

    SciTech Connect

    Romero, P.; Puerta, J.

    1996-12-31

    Electric tools for non-destructive water tree diagnostic in XLPE medium voltage cables, by means of DC and AC voltages are presented. The DC method is related to the determination of a non-linear dependence of the polarization current on the applied DC step voltage, in contrast to a linear dependence found in non-water tree-damaged cables. In both cases the current follows the Curie-von Schweidler empirical law, I(t) = I{sub 0}t{sup {minus}n}. The AC method is based on the measurement of the dispersion relation of both the loss factor and the capacitance in the low and very low frequency ranges by means of the Fourier Transform techniques. The devised measuring instrumentation is presented.

  17. Bouncing of a Droplet on Superhydrophobic Surface in AC Electrowetting

    NASA Astrophysics Data System (ADS)

    Kang, Kwan Hyoung; Lee, Seung Jun; Hong, Jiwoo

    2009-11-01

    Oscillation of a droplet is induced in ac electrowetting by time-dependent electrical wetting tension. A droplet placed on a superhydrophobic surface bounces up like a rubber ball when an ac signal is applied. The bouncing pattern is highly frequency dependent. We investigated how the shape deformation and bouncing of a droplet are affected by applied frequency. The droplet motion is analyzed with the spectral method. The droplet is modeled as a simple linear oscillator, and the mass and spring constants are determined based on analytical results. We found that bouncing occurs periodically at a resonance frequency of the droplet. The motion of a sessile droplet released from a fixed shape is analyzed based on the phase field method. The numerical results show qualitative agreement with the experimental results for a bouncing droplet. Details on the flow field inside a bouncing droplet will be discussed based on numerical results.

  18. SNL software manual for the ACS Data Analytics Project.

    SciTech Connect

    Stearley, Jon R.; McLendon, William Clarence, III; Rodrigues, Arun F.; Williams, Aaron S.; Hooper, Russell Warren; Robinson, David Gerald; Stickland, Michael G.

    2011-10-01

    In the ACS Data Analytics Project (also known as 'YumYum'), a supercomputer is modeled as a graph of components and dependencies, jobs and faults are simulated, and component fault rates are estimated using the graph structure and job pass/fail outcomes. This report documents the successful completion of all SNL deliverables and tasks, describes the software written by SNL for the project, and presents the data it generates. Readers should understand what the software tools are, how they fit together, and how to use them to reproduce the presented data and additional experiments as desired. The SNL YumYum tools provide the novel simulation and inference capabilities desired by ACS. SNL also developed and implemented a new algorithm, which provides faster estimates, at finer component granularity, on arbitrary directed acyclic graphs.

  19. On the possibility of reduction of Ac{sup 3+} to Ac{sup 2+} in Aqueous-ethanolic solutions of bivalent samarium

    SciTech Connect

    Mikheev, N.B.; Veleshko, I.E.; Kamenskaya, A.N.

    1995-07-01

    In view of contradictory data on the existence of Ac{sup 2+} in aqueous solutions, the possibility of actinium reduction was examined in aqueous-ethanolic solutions in which bivalent f-elements are more stable than in aqueous media. In the presence of bivalent samarium (E{sub Sm}{sup 0}3+/Sm 2+=-1.5 V) Ac(III) is not reduced to Ac(II). These results disagree with the previously published data on the radiopolarographic generation of Ac(II) in aqueous solutions.

  20. Challenges and solutions in medically managed ACS in the Asia-Pacific region: expert recommendations from the Asia-Pacific ACS Medical Management Working Group.

    PubMed

    Huo, Yong; Thompson, Peter; Buddhari, Wacin; Ge, Junbo; Harding, Scott; Ramanathan, Letchuman; Reyes, Eugenio; Santoso, Anwar; Tam, Li-Wah; Vijayaraghavan, Govindan; Yeh, Hung-I

    2015-03-15

    Acute coronary syndromes (ACS) remain a leading cause of mortality and morbidity in the Asia-Pacific (APAC) region. International guidelines advocate invasive procedures in all but low-risk ACS patients; however, a high proportion of ACS patients in the APAC region receive solely medical management due to a combination of unique geographical, socioeconomic, and population-specific barriers. The APAC ACS Medical Management Working Group recently convened to discuss the ACS medical management landscape in the APAC region. Local and international ACS guidelines and the global and APAC clinical evidence-base for medical management of ACS were reviewed. Challenges in the provision of optimal care for these patients were identified and broadly categorized into issues related to (1) accessibility/systems of care, (2) risk stratification, (3) education, (4) optimization of pharmacotherapy, and (5) cost/affordability. While ACS guidelines clearly represent a valuable standard of care, the group concluded that these challenges can be best met by establishing cardiac networks and individual hospital models/clinical pathways taking into account local risk factors (including socioeconomic status), affordability and availability of pharmacotherapies/invasive facilities, and the nature of local healthcare systems. Potential solutions central to the optimization of ACS medical management in the APAC region are outlined with specific recommendations.

  1. Removal of pharmaceutically active compounds (PhACs) and toxicological response of Cyperus alternifolius exposed to PhACs in microcosm constructed wetlands.

    PubMed

    Yan, Qing; Feng, Guozhong; Gao, Xu; Sun, Chengxiao; Guo, Jin-song; Zhu, Zhiwei

    2016-01-15

    This study investigated the effects of selected four pharmaceutically active compounds (PhACs) (carbamazepine, sulfamethoxazole, ofloxacin, and roxithromycin) on the photosynthesis and antioxidant enzymes of Cyperus alternifolius in constructed wetlands (CWs). Moreover, the removal and kinetics of PhACs in CWs were evaluated to explore the related removal mechanisms. Results showed that C. alternifolius can uptake and withstand certain PhACs. The PhAC tolerance of C. alternifolius might be attributed to their capacity to maintain relatively normal photosynthetic activity and elevated antioxidative defense. CWs offered comparable or even higher removal efficiencies for the selected PhACs compared with conventional WWTPs. The removal of the target PhACs was enhanced in the planted CWs versus the unplanted CWs mostly because of plant uptake and rhizosphere effects. In particular, carbamazepine, which is considered the most recalcitrant of the PhACs, was significantly reduced (p<0.05). The removal of target PhACs fitted into two distinct periods. The initial fast step (within the first 2 h) was essentially attributed to the adsorption onto the CW medium surface. The subsequent slow process (2-12 h) closely followed first-order kinetics probably because of the interaction between microorganisms and plants. The obtained results indicate that C. alternifolius can phytoremediate PhAC-contaminated waters in CWs. PMID:26465971

  2. Removal of pharmaceutically active compounds (PhACs) and toxicological response of Cyperus alternifolius exposed to PhACs in microcosm constructed wetlands.

    PubMed

    Yan, Qing; Feng, Guozhong; Gao, Xu; Sun, Chengxiao; Guo, Jin-song; Zhu, Zhiwei

    2016-01-15

    This study investigated the effects of selected four pharmaceutically active compounds (PhACs) (carbamazepine, sulfamethoxazole, ofloxacin, and roxithromycin) on the photosynthesis and antioxidant enzymes of Cyperus alternifolius in constructed wetlands (CWs). Moreover, the removal and kinetics of PhACs in CWs were evaluated to explore the related removal mechanisms. Results showed that C. alternifolius can uptake and withstand certain PhACs. The PhAC tolerance of C. alternifolius might be attributed to their capacity to maintain relatively normal photosynthetic activity and elevated antioxidative defense. CWs offered comparable or even higher removal efficiencies for the selected PhACs compared with conventional WWTPs. The removal of the target PhACs was enhanced in the planted CWs versus the unplanted CWs mostly because of plant uptake and rhizosphere effects. In particular, carbamazepine, which is considered the most recalcitrant of the PhACs, was significantly reduced (p<0.05). The removal of target PhACs fitted into two distinct periods. The initial fast step (within the first 2 h) was essentially attributed to the adsorption onto the CW medium surface. The subsequent slow process (2-12 h) closely followed first-order kinetics probably because of the interaction between microorganisms and plants. The obtained results indicate that C. alternifolius can phytoremediate PhAC-contaminated waters in CWs.

  3. Hybrid immersed interface-immersed boundary methods for AC dielectrophoresis

    SciTech Connect

    Hossan, Mohammad Robiul; Dillon, Robert; Dutta, Prashanta

    2014-08-01

    Dielectrophoresis, a nonlinear electrokinetic transport mechanism, has become popular in many engineering applications including manipulation, characterization and actuation of biomaterials, particles and biological cells. In this paper, we present a hybrid immersed interface–immersed boundary method to study AC dielectrophoresis where an algorithm is developed to solve the complex Poisson equation using a real variable formulation. An immersed interface method is employed to obtain the AC electric field in a fluid media with suspended particles and an immersed boundary method is used for the fluid equations and particle transport. The convergence of the proposed algorithm as well as validation of the hybrid scheme with experimental results is presented. In this paper, the Maxwell stress tensor is used to calculate the dielectrophoretic force acting on particles by considering the physical effect of particles in the computational domain. Thus, this study eliminates the approximations used in point dipole methods for calculating dielectrophoretic force. A comparative study between Maxwell stress tensor and point dipole methods for computing dielectrophoretic forces are presented. The hybrid method is used to investigate the physics of dielectrophoresis in microfluidic devices using an AC electric field. The numerical results show that with proper design and appropriate selection of applied potential and frequency, global electric field minima can be obtained to facilitate multiple particle trapping by exploiting the mechanism of negative dielectrophoresis. Our numerical results also show that electrically neutral particles form a chain parallel to the applied electric field irrespective of their initial orientation when an AC electric field is applied. This proposed hybrid numerical scheme will help to better understand dielectrophoresis and to design and optimize microfluidic devices.

  4. A calculable, transportable audio-frequency AC reference standard

    SciTech Connect

    Oldham, N.M.; Hetrick, P.S. ); Zeng, X. )

    1989-04-01

    A transportable ac voltage source is described, in which sinusoidal signals are synthesized digitally in the audio-frequency range. The rms value of the output waveform may be calculated by measuring the dc level of the individual steps used to generate the waveform. The uncertainty of this calculation at the 7-V level is typically less than +-5 ppm from 60 Hz to 2 kHz and less than +-10 ppm from 30 Hz to 15 kHz.

  5. Leonurenones A-C: Labdane diterpenes from Leonotis leonurus.

    PubMed

    He, Fang; Lindqvist, Charlotte; Harding, Wayne W

    2012-11-01

    Labdanes, leonurenones A-C, two known labdanes, luteolin 7-O-β-glucoside and luteolin were isolated and characterized from a commercial source of Leonotis leonurus. Genetic methods allowed for identification of the plant material. The leonurenones contain an uncommon α,β-unsaturated enone moiety in ring B, and leonurenones A and B were evaluated in a competitive inhibition assay at the GABA A neuroreceptor site.

  6. Effective AC needleless and collectorless electrospinning for yarn production.

    PubMed

    Pokorny, P; Kostakova, E; Sanetrnik, F; Mikes, P; Chvojka, J; Kalous, T; Bilek, M; Pejchar, K; Valtera, J; Lukas, D

    2014-12-28

    Nanofibrous materials are essential components for a wide range of applications, particularly in the fields of medicine and material engineering. These include protective materials, sensors, cosmetics, hygiene, filtration and energy storage. The most widely used and researched technology in these fields is electrospinning. This method for producing fibers yields highly promising results thanks to its versatility and simplicity. Electrospinning is employed in multiple forms, among which needle and needleless direct current (DC) variants are the most distinctive. The former is based on the generation of just one single jet from a nozzle; hence this fabrication process is not very productive. The latter uses the destabilization of free liquid surfaces by means of an electric field, which enhances the throughput since it produces numerous jets, emitted from the surfaces of rollers, spheres, strings and spirals. However, although some progress in total producibility has been achieved, the efficiency of the DC method still remains relatively low. A further drawback of DC electrospinning is that both variants need a collector, which makes it difficult to combine DC electrospinning easily with other technologies due to the presence of the high field strength within the entire spinning zone. This paper describes our experiments with AC electrospinning. We show that alternating current (AC) electrospinning based on a needleless spinning-electrode provides a highly productive smoke-like aerogel composed of nanofibers. This aerogel rises rapidly from the electrode like a thin plume of smoke, without any need for a collector. Our work shows that AC needleless electrospinning gains its efficiency and collector-less feature thanks to the creation of a perpetually charge-changing virtual counter-electrode composed of the nanofibers emitted. High-speed camera recordings demonstrate the formation mechanism of the nanofibrous plume, which is wafted by an electric wind. This wind

  7. Heat Capacity Measurements by Simultaneous Relaxation and AC-Calorimetry

    NASA Astrophysics Data System (ADS)

    Kashuri, H.; Kashuri, K.; Iannacchione, G. S.

    2012-02-01

    A high-resolution method for measuring the heat capacity Cp using simultaneously AC and Relaxation Calorimetry techniques has been developed. This technique is useful for both first and second-order phase transitions of liquids and complex fluids. The difference of the Cp's measured by the Relaxation and AC calorimetry is a direct measurement of a phase transitions' latent heat. As a test, the Cp of two cyanobiphenyl liquid crystals, 5CB and 8CB, were measured using a square wave modulation pulse train over a base temperature range from 300 to 320 K in which 5CB exhibits a first-order phase transition and 8CB exhibits a first and second-order phase transition. Fourier transform analysis allows for the direct Cp measurement at the fundamental frequency of the square wave pulse train (as well as higher frequency orders) as function of temperature (i.e., AC-mode). The heating and cooling relaxations at the beginning and end of the square pulse heating allows for a relaxation analysis of Cp by applying the dual slope-method that includes all enthalpic conversions.

  8. Transcriptome modulations due to A/C2 plasmid acquisition.

    PubMed

    Lang, Kevin S; Johnson, Timothy J

    2015-07-01

    Plasmids play an important role in driving the genetic diversity of bacteria. Horizontal gene transfer via plasmids is crucial for the dissemination of antimicrobial resistance genes. Many factors contribute to the persistence of plasmids within bacterial populations, and it has been suggested that epistatic interactions between the host chromosome and plasmid contribute to the fitness of a particular plasmid-host combination. However, such interactions have been shown to differ between bacterial hosts. In this study, RNA-Seq was performed in six different strains, spanning three species, to characterize the influence of host background on the A/C2 plasmid transcriptome. In five of these strains, chromosomal transcriptomes were compared in the presence and absence of A/C2 plasmid pAR060302. Host-specific effects on plasmid gene expression were identified, and acquisition of pAR060302 resulted in changes in the expression of chromosomal genes involved in metabolism and energy production. These results suggest that A/C2 plasmid fitness is, in part, dependent on host chromosome content, as well as environmental factors. PMID:26079188

  9. 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.%.

  10. Strongly nonlinear dynamics of electrolytes in large ac voltages.

    PubMed

    Højgaard Olesen, Laurits; Bazant, Martin Z; Bruus, Henrik

    2010-07-01

    We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two features--significant salt depletion in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasiequilibrium structure of the double layers. The former leads to the prediction of "ac capacitive desalination" since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion layers. The latter is associated with transient diffusion limitation, which drives the formation and collapse of space-charge layers, even in the absence of any net Faradaic current through the cell. We also predict that steric effects of finite ion sizes (going beyond dilute-solution theory) act to suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena.

  11. 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) 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.%.

  12. {alpha} decay of the new isotope {sup 206}Ac

    SciTech Connect

    Eskola, K.; Kuusiniemi, P.; Leino, M.; Cocks, J.F.; Enqvist, T.; Hurskanen, S.; Kettunen, H.; Trzaska, W.H.; Uusitalo, J.; Allatt, R.G.; Greenlees, P.T.; Page, R.D.

    1998-01-01

    The new neutron-deficient nuclide {sup 206}Ac was produced by bombarding a {sup 175}Lu target with 5.5 MeV/nucleon {sup 36}Ar ions. The evaporation residues were separated in flight by a gas-filled separator and subsequently identified by the {alpha}-{alpha} position and time correlation method. {sup 206}Ac was found to have two {alpha} particle emitting isomeric levels with half-lives of (22{sub {minus}5}{sup +9}) ms and (33{sub {minus}9}{sup +22}) ms, and with {alpha} particle energies of (7790{plus_minus}30) keV and (7750{plus_minus}20) keV, respectively. The former isomer is tentatively assigned to a J{sup {pi}}=3{sup +} level and the latter to a J{sup {pi}}=10{sup {minus}} level, both of which are also seen in the daughter and granddaughter nuclides {sup 202}Fr and {sup 198}At. Improved values of (27{sub {minus}6}{sup +11}) ms and (7693{plus_minus}25) keV for the half-life and {alpha} particle energy of {sup 207}Ac are also reported. {copyright} {ital 1998} {ital The American Physical Society}

  13. 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.

  14. AC electrokinetic manipulation of selenium nanoparticles for potential nanosensor applications

    SciTech Connect

    Mahmoodi, Seyed Reza; Bayati, Marzieh; Hosseinirad, Somayeh; Foroumadi, Alireza; Gilani, Kambiz; Rezayat, Seyed Mahdi

    2013-03-15

    Highlights: ► Se nanoparticles were synthesized using a reverse-microemulsion process. ► AC osmotic fluid flow repulses the particles from electrode edges. ► Dielectrophoretic force attracts the particles to electrode edges. ► Dielectrophoresis electrode showed non-ohmic behavior. ► The device can potentially be used as a nanosensor. - Abstract: We report the AC electrokinetic behavior of selenium (Se) nanoparticles for electrical characterization and possible application as micro/nano devices. selenium Se nanoparticles were successfully synthesized using a reverse-microemulsion process and investigated structurally using X-ray diffraction and transmission electron microscope. Interdigitated castellated ITO and non-castellated platinum electrodes were employed for manipulation of suspended materials in the fluid. Using ITO electrodes at low frequency limits resulted in deposition of Se particles on electrode surface. When Se particles exposed to platinum electrodes in the 10 Hz–1 kHz range and V {sub p−p}> 8, AC osmotic fluid flow repulses the particles from electrode edges. However, in 10 kHz–10 MHz range and V {sub p−p}> 5, dielectrophoretic force attracts the particles to electrode edges. As the Se particle concentration increased, the trapped Se particles were aligned along the electric field line and bridged the electrode gap. The device was characterized and can potentially be useful in making micro/nano electronic devices.

  15. 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%.

  16. 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.

  17. The ST-ECF ACS Grism Hubble Legacy Archive Project

    NASA Astrophysics Data System (ADS)

    Kümmel, M.; Kuntschner, H.; Walsh, J. R.; Lombardi, M.; Stoehr, F.; Haase, J.; Hook, R. N.; Rosati, P.; Micol, A.; Fosbury, R.; Freudling, W.

    2009-09-01

    In 2006 the Space Telescope - European Coordinating Facility (ST-ECF), together with its partners at the STScI and the CADC, started a project to build a Hubble Legacy Archive (HLA): a collection of high-level Hubble data products and access tools to ease scientific analysis in the age of the Virtual Observatory. The ST-ECF has focused on providing extracted spectra from slitless spectroscopy HST images. The slitless NICMOS G141 data were presented at previous ADASS meetings and have already been released. In this contribution we present an overview of the ongoing project of processing the ACS/WFC G800L data which cover a larger area and contain more spectra. There are around 150 ACS/WFC G800L datasets covering an area of ˜ 600 arcmin^2, and we expect to extract and publish about 20,000 fully-calibrated spectra. We discuss the techniques and methods that were developed to automatically extract the spectra from the observations and present a selection of ACS/WFC G800L spectra as examples.

  18. 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%.

  19. Production of AC-225 and application of the BI-213 daughter in cancer therapy

    NASA Astrophysics Data System (ADS)

    Koch, L.; Apostolidis, C.; Janssens, W.; Molinet, R.; van Geel, J.

    1999-01-01

    There are several ongoing medical trials to use Bi-213 conjugated to monoclonal antibodies to kill tumour-cells of various cancer types. The institute is supplying Ac-225 generators for the test and is itself engaged in in-vitro cytotoxicity tests. Nuclear reactions leading to Ac-225 are discussed. The present supply of Ac-225 stems from Th-229 decay obtained from aged U-233. From the possible alternative the reactions Ra-226 (p, 2n) Ac-225 is presently favoured. The fabrication of a Ac-225 for Bi-213 generator will be described.

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

    SciTech Connect

    Dunn, Tom; Kamenev, Alex

    2014-06-21

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

  1. QPSK modulation for AC-power-signal-biased visible light communication system

    NASA Astrophysics Data System (ADS)

    Liu, Yu-Feng; Yeh, Chien-Hung; Chow, Chi-Wai; Liu, Yang

    2013-01-01

    With the integration of light emitting diode (LED), visible light communication (VLC) can provide wireless communication link using the lightning system. Due to the consideration of power efficiency, AC-LED has the design of reducing energy waste with alternating current from the power outlet. In this work, we propose an AC-power-signalbiased system that provides communication on both DC-LED and AC-LED. The bias circuit is designed to combine ACpower signal and the message signal with QPSK format. This driving scheme needs no AC-to-DC converters and it is suitable for driving AC LED. Synchronization is completed to avoid threshold effect of LED.

  2. Quantification of phnAc and nahAc in contaminated New Zealand soils by competitive PCR

    SciTech Connect

    Laurie, A.D.; Lloyd-Jones, G.

    2000-05-01

    Unculturable polycyclic aromatic hydrocarbon (PAH)-degrading bacteria are a significant reservoir of the microbial potential to catabolize low-molecular-weight PAHs. The population of these bacteria is larger than the population of nah-like bacteria that are the dominant organisms in culture-based studies. The authors used the recently described phn genes of Burkholderia sp. strain RP007, which feature only rarely in culture-based studies, as an alternative genotype for naphthalene and phenanthrene degradation and compared this genotype with the genotypically distinct but ubiquitous nah-like class in different soils. Competitive PCR quantification of phnAc and nahAc, which encode the iron sulfur protein large ({alpha}) subunits of PAH dioxygenases in nah-like and phn catabolic operons, revealed that the phn genotype can have a greater ecological significance than the nah-like genotype.

  3. Loss of ACS7 confers abiotic stress tolerance by modulating ABA sensitivity and accumulation in Arabidopsis.

    PubMed

    Dong, Hui; Zhen, Zhiqin; Peng, Jinying; Chang, Li; Gong, Qingqiu; Wang, Ning Ning

    2011-10-01

    The phytohormones ethylene and abscisic acid (ABA) play essential roles in the abiotic stress adaptation of plants, with both cross-talk of ethylene signalling and ABA biosynthesis and signalling reported. Any reciprocal effects on each other's biosynthesis, however, remain elusive. ACC synthase (ACS) acts as the key enzyme in ethylene biosynthesis. A pilot study on changes in ACS promoter activities in response to abiotic stresses revealed the unique involvement in abiotic stress responses of the only type 3 ACC synthase, ACS7, among all nine ACSs of Arabidopsis. Hence an acs7 mutant was characterized and its abiotic stress responses were analysed. The acs7 mutant germinated slightly faster than the wild type and subsequently maintained a higher growth rate at the vegetative growth stage. Ethylene emission of acs7 was merely one-third of that of the wild type. acs7 exhibited enhanced tolerance to salt, osmotic, and heat stresses. Furthermore, acs7 seeds were hypersensitive to both ABA and glucose during germination. Transcript analyses revealed that acs7 had elevated transcript levels of the stress-responsive genes involved in the ABA-dependent pathway under salt stress. The ABA level was also higher in acs7 following salt treatment. Our data suggest that ACS7 acts as a negative regulator of ABA sensitivity and accumulation under stress and appears as a node in the cross-talk between ethylene and ABA.

  4. Phosphor-in-glass for high-powered remote-type white AC-LED.

    PubMed

    Lin, Hang; Wang, Bo; Xu, Ju; Zhang, Rui; Chen, Hui; Yu, Yunlong; Wang, Yuansheng

    2014-12-10

    The high-powered alternating current (AC) light-emitting diode (LED) (AC-LED), featuring low cost, high energy utilization efficiency, and long service life, will become a new economic growth point in the field of semiconductor lighting. However, flicker of AC-LED in the AC cycles is not healthy for human eyes, and therefore need to be restrained. Herein we report an innovation of persistent "phosphor-in-glass" (PiG) for the remote-type AC-LED, whose afterglow can be efficiently activated by the blue light. It is experimentally demonstrated that the afterglow decay of PiG in the microsecond range can partly compensate the AC time gap. Moreover, the substitution of inorganic glass for organic resins or silicones as the encapsulants would bring out several technological benefits to AC-LED, such as good heat-dissipation, low glare, and excellent physical/chemical stability. PMID:25329651

  5. Phosphor-in-glass for high-powered remote-type white AC-LED.

    PubMed

    Lin, Hang; Wang, Bo; Xu, Ju; Zhang, Rui; Chen, Hui; Yu, Yunlong; Wang, Yuansheng

    2014-12-10

    The high-powered alternating current (AC) light-emitting diode (LED) (AC-LED), featuring low cost, high energy utilization efficiency, and long service life, will become a new economic growth point in the field of semiconductor lighting. However, flicker of AC-LED in the AC cycles is not healthy for human eyes, and therefore need to be restrained. Herein we report an innovation of persistent "phosphor-in-glass" (PiG) for the remote-type AC-LED, whose afterglow can be efficiently activated by the blue light. It is experimentally demonstrated that the afterglow decay of PiG in the microsecond range can partly compensate the AC time gap. Moreover, the substitution of inorganic glass for organic resins or silicones as the encapsulants would bring out several technological benefits to AC-LED, such as good heat-dissipation, low glare, and excellent physical/chemical stability.

  6. 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.

  7. 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

  8. Mapping the conformational epitope of a neutralizing antibody (AcV1) directed against the AcMNPV GP64 protein

    SciTech Connect

    Zhou Jian; Blissard, Gary W. . E-mail: gwb1@cornell.edu

    2006-09-01

    The envelope glycoprotein GP64 of Autographa californica nucleopolyhedrovirus (AcMNPV) is necessary and sufficient for the acid-induced membrane fusion activity that is required for fusion of the budded virus (BV) envelope and the endosome membrane during virus entry. Infectivity of the budded virus (BV) is neutralized by AcV1, a monoclonal antibody (MAb) directed against GP64. Prior studies indicated that AcV1 recognizes a conformational epitope and does not inhibit virus attachment to the cell, but instead inhibits entry at a step following virus attachment. We found that AcV1 recognition of GP64 was lost upon exposure of GP64 to low pH (pH 4.5) and restored by returning GP64 to pH 6.2. In addition, the AcV1 epitope was lost upon denaturation of GP64 in SDS, but the AcV1 epitope was restored by refolding the protein in the absence of SDS. Using truncated GP64 proteins expressed in insect cells, we mapped the AcV1 epitope to a 24 amino acid region in the central variable domain of GP64. When sequences within the mapped AcV1 epitope were substituted with a c-Myc epitope and the resulting construct was used to replace wt GP64 in recombinant AcMNPV viruses, the modified GP64 protein appeared to function normally. However, an anti-c-Myc monoclonal antibody did not neutralize infectivity of those viruses. Because binding of the c-Myc MAb to the same site in the GP64 sequence did not result in neutralization, these studies suggest that AcV1 neutralization may result from a specific structural constraint caused by AcV1 binding and not simply by steric hindrance caused by antibody binding at this position in GP64.

  9. Early Function of the Abutilon Mosaic Virus AC2 Gene as a Replication Brake

    PubMed Central

    Krenz, Björn; Deuschle, Kathrin; Deigner, Tobias; Unseld, Sigrid; Kepp, Gabi; Wege, Christina; Kleinow, Tatjana

    2015-01-01

    ABSTRACT The C2/AC2 genes of monopartite/bipartite geminiviruses of the genera Begomovirus and Curtovirus encode important pathogenicity factors with multiple functions described so far. A novel function of Abutilon mosaic virus (AbMV) AC2 as a replication brake is described, utilizing transgenic plants with dimeric inserts of DNA B or with a reporter construct to express green fluorescent protein (GFP). Their replicational release upon AbMV superinfection or the individual and combined expression of epitope-tagged AbMV AC1, AC2, and AC3 was studied. In addition, the effects were compared in the presence and in the absence of an unrelated tombusvirus suppressor of silencing (P19). The results show that AC2 suppresses replication reproducibly in all assays and that AC3 counteracts this effect. Examination of the topoisomer distribution of supercoiled DNA, which indicates changes in the viral minichromosome structure, did not support any influence of AC2 on transcriptional gene silencing and DNA methylation. The geminiviral AC2 protein has been detected here for the first time in plants. The experiments revealed an extremely low level of AC2, which was slightly increased if constructs with an intron and a hemagglutinin (HA) tag in addition to P19 expression were used. AbMV AC2 properties are discussed with reference to those of other geminiviruses with respect to charge, modification, and size in order to delimit possible reasons for the different behaviors. IMPORTANCE The (A)C2 genes encode a key pathogenicity factor of begomoviruses and curtoviruses in the plant virus family Geminiviridae. This factor has been implicated in the resistance breaking observed in agricultural cotton production. AC2 is a multifunctional protein involved in transcriptional control, gene silencing, and regulation of basal biosynthesis. Here, a new function of Abutilon mosaic virus AC2 in replication control is added as a feature of this protein in viral multiplication, providing a novel

  10. Isolation of an acetyl-CoA synthetase gene (ZbACS2) from Zygosaccharomyces bailii.

    PubMed

    Rodrigues, Fernando; Zeeman, Anne-Marie; Cardoso, Helena; Sousa, Maria João; Steensma, H Yde; Côrte-Real, Manuela; Leão, Cecília

    2004-03-01

    A gene homologous to Saccharomyces cerevisiae ACS genes, coding for acetyl-CoA synthetase, has been cloned from the yeast Zygosaccharomyces bailii ISA 1307, by using reverse genetic approaches. A probe obtained by PCR amplification from Z. bailii DNA, using primers derived from two conserved regions of yeast ACS proteins, RIGAIHSVVF (ScAcs1p; 210-219) and RVDDVVNVSG (ScAcs1p; 574-583), was used for screening a Z. bailii genomic library. Nine clones with partially overlapping inserts were isolated. The sequenced DNA fragment contains a complete ORF of 2027 bp (ZbACS2) and the deduced polypeptide shares significant homologies with the products of ACS2 genes from S. cerevisiae and Kluyveromyces lactis (81% and 82% identity and 84% and 89% similarity, respectively). Phylogenetic analysis shows that the sequence of Zbacs2 is more closely related to the sequences from Acs2 than to those from Acs1 proteins. Moreover, this analysis revealed that the gene duplication producing Acs1 and Acs2 proteins has occurred in the common ancestor of S. cerevisiae, K. lactis, Candida albicans, C. glabrata and Debaryomyces hansenii lineages. Additionally, the cloned gene allowed growth of S. cerevisiae Scacs2 null mutant, in medium containing glucose as the only carbon and energy source, indicating that it encodes a functional acetyl-CoA synthetase. Also, S. cerevisiae cells expressing ZbACS2 have a shorter lag time, in medium containing glucose (2%, w/v) plus acetic acid (0.1-0.35%, v/v). No differences in cell response to acetic acid stress were detected both by specific growth and death rates. The mode of regulation of ZbACS2 appears to be different from ScACS2 and KlACS2, being subject to repression by a glucose pulse in acetic acid-grown cells. PMID:15042592

  11. 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.

  12. 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

  13. Strongly nonlinear dynamics of electrolytes in large ac voltages

    NASA Astrophysics Data System (ADS)

    Højgaard Olesen, Laurits; Bazant, Martin Z.; Bruus, Henrik

    2010-07-01

    We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two features—significant salt depletion in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasiequilibrium structure of the double layers. The former leads to the prediction of “ac capacitive desalination” since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion layers. The latter is associated with transient diffusion limitation, which drives the formation and collapse of space-charge layers, even in the absence of any net Faradaic current through the cell. We also predict that steric effects of finite ion sizes (going beyond dilute-solution theory) act to suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena.

  14. Concurrent Electroencephalography Recording During Transcranial Alternating Current Stimulation (tACS)

    PubMed Central

    Fehér, Kristoffer D.; Morishima, Yosuke

    2016-01-01

    Oscillatory brain activities are considered to reflect the basis of rhythmic changes in transmission efficacy across brain networks and are assumed to integrate cognitive neural processes. Transcranial alternating current stimulation (tACS) holds the promise to elucidate the causal link between specific frequencies of oscillatory brain activity and cognitive processes. Simultaneous electroencephalography (EEG) recording during tACS would offer an opportunity to directly explore immediate neurophysiological effects of tACS. However, it is not trivial to measure EEG signals during tACS, as tACS creates a huge artifact in EEG data. Here we explain how to set up concurrent tACS-EEG experiments. Two necessary considerations for successful EEG recording while applying tACS are highlighted. First, bridging of the tACS and EEG electrodes via leaking EEG gel immediately saturates the EEG amplifier. To avoid bridging via gel, the viscosity of the EEG gel is the most important parameter. The EEG gel must be viscous to avoid bridging, but at the same time sufficiently fluid to create contact between the tACS electrode and the scalp. Second, due to the large amplitude of the tACS artifact, it is important to consider using an EEG system with a high resolution analog-to-digital (A/D) converter. In particular, the magnitude of the tACS artifact can exceed 100 mV at the vicinity of a stimulation electrode when 1 mA tACS is applied. The resolution of the A/D converter is of importance to measure good quality EEG data from the vicinity of the stimulation site. By following these guidelines for the procedures and technical considerations, successful concurrent EEG recording during tACS will be realized. PMID:26862814

  15. Power Electronic Transformer based Three-Phase PWM AC Drives

    NASA Astrophysics Data System (ADS)

    Basu, Kaushik

    A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

  16. A PWM transistor inverter for an ac electric vehicle drive

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1981-01-01

    A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.

  17. Atomic Mass and Nuclear Binding Energy for Ac-272 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-272 (Actinium, atomic number Z = 89, mass number A = 272).

  18. Atomic Mass and Nuclear Binding Energy for Ac-295 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-295 (Actinium, atomic number Z = 89, mass number A = 295).

  19. Atomic Mass and Nuclear Binding Energy for Ac-234 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-234 (Actinium, atomic number Z = 89, mass number A = 234).

  20. Atomic Mass and Nuclear Binding Energy for Ac-273 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-273 (Actinium, atomic number Z = 89, mass number A = 273).

  1. Atomic Mass and Nuclear Binding Energy for Ac-242 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-242 (Actinium, atomic number Z = 89, mass number A = 242).

  2. Atomic Mass and Nuclear Binding Energy for Ac-251 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-251 (Actinium, atomic number Z = 89, mass number A = 251).

  3. Atomic Mass and Nuclear Binding Energy for Ac-285 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-285 (Actinium, atomic number Z = 89, mass number A = 285).

  4. Atomic Mass and Nuclear Binding Energy for Ac-278 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-278 (Actinium, atomic number Z = 89, mass number A = 278).

  5. Atomic Mass and Nuclear Binding Energy for Ac-226 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-226 (Actinium, atomic number Z = 89, mass number A = 226).

  6. Atomic Mass and Nuclear Binding Energy for Ac-270 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-270 (Actinium, atomic number Z = 89, mass number A = 270).

  7. Atomic Mass and Nuclear Binding Energy for Ac-245 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-245 (Actinium, atomic number Z = 89, mass number A = 245).

  8. Atomic Mass and Nuclear Binding Energy for Ac-279 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-279 (Actinium, atomic number Z = 89, mass number A = 279).

  9. Atomic Mass and Nuclear Binding Energy for Ac-243 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-243 (Actinium, atomic number Z = 89, mass number A = 243).

  10. Atomic Mass and Nuclear Binding Energy for Ac-257 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-257 (Actinium, atomic number Z = 89, mass number A = 257).

  11. Atomic Mass and Nuclear Binding Energy for Ac-293 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-293 (Actinium, atomic number Z = 89, mass number A = 293).

  12. Atomic Mass and Nuclear Binding Energy for Ac-259 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-259 (Actinium, atomic number Z = 89, mass number A = 259).

  13. Atomic Mass and Nuclear Binding Energy for Ac-274 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-274 (Actinium, atomic number Z = 89, mass number A = 274).

  14. Atomic Mass and Nuclear Binding Energy for Ac-225 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-225 (Actinium, atomic number Z = 89, mass number A = 225).

  15. Atomic Mass and Nuclear Binding Energy for Ac-282 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-282 (Actinium, atomic number Z = 89, mass number A = 282).

  16. Atomic Mass and Nuclear Binding Energy for Ac-229 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-229 (Actinium, atomic number Z = 89, mass number A = 229).

  17. Atomic Mass and Nuclear Binding Energy for Ac-292 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-292 (Actinium, atomic number Z = 89, mass number A = 292).

  18. Atomic Mass and Nuclear Binding Energy for Ac-238 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-238 (Actinium, atomic number Z = 89, mass number A = 238).

  19. Atomic Mass and Nuclear Binding Energy for Ac-227 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-227 (Actinium, atomic number Z = 89, mass number A = 227).

  20. Atomic Mass and Nuclear Binding Energy for Ac-247 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-247 (Actinium, atomic number Z = 89, mass number A = 247).

  1. Atomic Mass and Nuclear Binding Energy for Ac-231 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-231 (Actinium, atomic number Z = 89, mass number A = 231).

  2. Atomic Mass and Nuclear Binding Energy for Ac-287 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-287 (Actinium, atomic number Z = 89, mass number A = 287).

  3. Atomic Mass and Nuclear Binding Energy for Ac-232 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-232 (Actinium, atomic number Z = 89, mass number A = 232).

  4. Atomic Mass and Nuclear Binding Energy for Ac-244 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-244 (Actinium, atomic number Z = 89, mass number A = 244).

  5. Atomic Mass and Nuclear Binding Energy for Ac-241 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-241 (Actinium, atomic number Z = 89, mass number A = 241).

  6. Atomic Mass and Nuclear Binding Energy for Ac-277 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-277 (Actinium, atomic number Z = 89, mass number A = 277).

  7. Atomic Mass and Nuclear Binding Energy for Ac-252 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-252 (Actinium, atomic number Z = 89, mass number A = 252).

  8. Atomic Mass and Nuclear Binding Energy for Ac-264 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-264 (Actinium, atomic number Z = 89, mass number A = 264).

  9. Atomic Mass and Nuclear Binding Energy for Ac-265 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-265 (Actinium, atomic number Z = 89, mass number A = 265).

  10. Atomic Mass and Nuclear Binding Energy for Ac-230 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-230 (Actinium, atomic number Z = 89, mass number A = 230).

  11. Atomic Mass and Nuclear Binding Energy for Ac-256 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-256 (Actinium, atomic number Z = 89, mass number A = 256).

  12. Atomic Mass and Nuclear Binding Energy for Ac-289 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-289 (Actinium, atomic number Z = 89, mass number A = 289).

  13. Atomic Mass and Nuclear Binding Energy for Ac-268 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-268 (Actinium, atomic number Z = 89, mass number A = 268).

  14. Atomic Mass and Nuclear Binding Energy for Ac-235 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-235 (Actinium, atomic number Z = 89, mass number A = 235).

  15. Atomic Mass and Nuclear Binding Energy for Ac-228 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-228 (Actinium, atomic number Z = 89, mass number A = 228).

  16. Atomic Mass and Nuclear Binding Energy for Ac-290 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-290 (Actinium, atomic number Z = 89, mass number A = 290).

  17. Atomic Mass and Nuclear Binding Energy for Ac-223 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-223 (Actinium, atomic number Z = 89, mass number A = 223).

  18. Atomic Mass and Nuclear Binding Energy for Ac-288 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-288 (Actinium, atomic number Z = 89, mass number A = 288).

  19. Atomic Mass and Nuclear Binding Energy for Ac-275 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-275 (Actinium, atomic number Z = 89, mass number A = 275).

  20. Atomic Mass and Nuclear Binding Energy for Ac-237 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-237 (Actinium, atomic number Z = 89, mass number A = 237).

  1. Atomic Mass and Nuclear Binding Energy for Ac-224 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-224 (Actinium, atomic number Z = 89, mass number A = 224).

  2. Atomic Mass and Nuclear Binding Energy for Ac-250 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-250 (Actinium, atomic number Z = 89, mass number A = 250).

  3. Atomic Mass and Nuclear Binding Energy for Ac-249 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-249 (Actinium, atomic number Z = 89, mass number A = 249).

  4. Atomic Mass and Nuclear Binding Energy for Ac-262 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-262 (Actinium, atomic number Z = 89, mass number A = 262).

  5. Atomic Mass and Nuclear Binding Energy for Ac-258 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-258 (Actinium, atomic number Z = 89, mass number A = 258).

  6. Atomic Mass and Nuclear Binding Energy for Ac-281 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-281 (Actinium, atomic number Z = 89, mass number A = 281).

  7. Atomic Mass and Nuclear Binding Energy for Ac-294 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-294 (Actinium, atomic number Z = 89, mass number A = 294).

  8. Atomic Mass and Nuclear Binding Energy for Ac-240 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-240 (Actinium, atomic number Z = 89, mass number A = 240).

  9. Atomic Mass and Nuclear Binding Energy for Ac-253 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-253 (Actinium, atomic number Z = 89, mass number A = 253).

  10. Atomic Mass and Nuclear Binding Energy for Ac-280 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-280 (Actinium, atomic number Z = 89, mass number A = 280).

  11. Atomic Mass and Nuclear Binding Energy for Ac-291 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-291 (Actinium, atomic number Z = 89, mass number A = 291).

  12. Atomic Mass and Nuclear Binding Energy for Ac-269 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-269 (Actinium, atomic number Z = 89, mass number A = 269).

  13. Atomic Mass and Nuclear Binding Energy for Ac-266 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-266 (Actinium, atomic number Z = 89, mass number A = 266).

  14. Atomic Mass and Nuclear Binding Energy for Ac-263 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-263 (Actinium, atomic number Z = 89, mass number A = 263).

  15. Atomic Mass and Nuclear Binding Energy for Ac-283 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-283 (Actinium, atomic number Z = 89, mass number A = 283).

  16. Atomic Mass and Nuclear Binding Energy for Ac-286 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-286 (Actinium, atomic number Z = 89, mass number A = 286).

  17. Atomic Mass and Nuclear Binding Energy for Ac-261 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-261 (Actinium, atomic number Z = 89, mass number A = 261).

  18. Atomic Mass and Nuclear Binding Energy for Ac-236 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-236 (Actinium, atomic number Z = 89, mass number A = 236).

  19. Atomic Mass and Nuclear Binding Energy for Ac-239 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-239 (Actinium, atomic number Z = 89, mass number A = 239).

  20. Atomic Mass and Nuclear Binding Energy for Ac-246 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-246 (Actinium, atomic number Z = 89, mass number A = 246).

  1. Atomic Mass and Nuclear Binding Energy for Ac-271 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-271 (Actinium, atomic number Z = 89, mass number A = 271).

  2. Atomic Mass and Nuclear Binding Energy for Ac-260 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-260 (Actinium, atomic number Z = 89, mass number A = 260).

  3. Atomic Mass and Nuclear Binding Energy for Ac-248 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-248 (Actinium, atomic number Z = 89, mass number A = 248).

  4. Atomic Mass and Nuclear Binding Energy for Ac-255 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-255 (Actinium, atomic number Z = 89, mass number A = 255).

  5. Atomic Mass and Nuclear Binding Energy for Ac-276 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-276 (Actinium, atomic number Z = 89, mass number A = 276).

  6. Atomic Mass and Nuclear Binding Energy for Ac-233 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-233 (Actinium, atomic number Z = 89, mass number A = 233).

  7. Atomic Mass and Nuclear Binding Energy for Ac-284 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-284 (Actinium, atomic number Z = 89, mass number A = 284).

  8. Atomic Mass and Nuclear Binding Energy for Ac-254 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-254 (Actinium, atomic number Z = 89, mass number A = 254).

  9. Atomic Mass and Nuclear Binding Energy for Ac-267 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-267 (Actinium, atomic number Z = 89, mass number A = 267).

  10. Topological Instabilities in ac-Driven Bosonic Systems.

    PubMed

    Engelhardt, G; Benito, M; Platero, G; Brandes, T

    2016-07-22

    Under nonequilibrium conditions, bosonic modes can become dynamically unstable with an exponentially growing occupation. On the other hand, topological band structures give rise to symmetry protected midgap states. In this Letter, we investigate the interplay of instability and topology. Thereby, we establish a general relation between topology and instability under ac driving. We apply our findings to create dynamical instabilities which are strongly localized at the boundaries of a finite-size system. As these localized instabilities are protected by symmetry, they can be considered as topological instabilities. PMID:27494478

  11. Lipid Bilayer Vesicle Dynamics in AC Electric Fields

    NASA Astrophysics Data System (ADS)

    McConnell, Lane; Vlahovska, Petia; Miksis, Michael

    2014-11-01

    Vesicles are closed, fluid-filled lipid bilayers which are mechanically similar to biological cells and which undergo shape transitions in the presence of electric fields. Here we model the vesicle membrane as an infinitely thin, capacitive, area-incompressible interface with the surrounding fluids acting as charge-advecting leaky dielectrics. We then implement the boundary integral method to numerically investigate the dynamics of a vesicle in various AC electric field profiles. Our numerical results are then compared with recent small deformation theory and experimental data. We also note our observation of a new theoretical vesicle behavior that has yet to be observed experimentally.

  12. Atomic Mass and Nuclear Binding Energy for Ac-222 (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 atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ac-222 (Actinium, atomic number Z = 89, mass number A = 222).

  13. dc-to-ac power converter for fuel cell system

    SciTech Connect

    Kawabata, T.; Asaeda, T.; Hamasaki, Y.; Yutani, T.

    1983-10-01

    As the interface between fuel cells and the utility line, a self-commutated inverter is preferred to a line-commutated inverter because of its easy controllability. Using the gate turn off (GTO) thyristors, this inverter can have high efficiency and simple circuit configurations. This paper describes the design features and test results of the dc-to-ac power converter, which is principally composed of four-phase transistor chopper and 12-pulse GTO inverter, for a 50kW experimental fuel cell power system. Furthermore, new GTO inverter which improves the circuit efficiency is presented. Special emphasis is placed on a detailed analysis and evaluation of this GTO inverter.

  14. An ac microcalorimeter employing a diode laser as a heater

    NASA Astrophysics Data System (ADS)

    Marone, M. J.; Payne, J. E.

    1997-12-01

    We have built an ac microcalorimeter which uses a diode laser as the heater. The absence of a contact heater reduces the total addendum. This method has several advantages over the typical quartz lamp and mechanical chopper wheel configuration. The laser is modulated by a lock-in amplifier which provides a wider choice of operating frequencies, typically from 0.2 to 50 Hz. The microcalorimeter has been used from near room temperature to 5 K. Single-crystal samples of YBCO with a mass as small as 4 μg have been measured. The device is particularly useful in the study of whiskers and other very small samples.

  15. Complex Calorimeter with AC- and Relaxation-Mode Operation

    NASA Astrophysics Data System (ADS)

    Ema, Kenji; Uematsu, Takashi; Sugata, Atsushi; Yao, Haruhiko

    1993-04-01

    A complex calorimeter has been developed. This calorimeter, which can be operated both in the ac mode and the relaxation mode using the same sample cell and the same apparatus settings, uses only a small amount (30-50 mg) of sample. An application to measurements in the vicinity of the antiferroelectric phase transitions in the liquid crystal MHPOBC(4-(1-methylheptyloxycarbonyl)-phenyl 4'-octyloxybiphenyl-4-carboxylate) is demonstrated. It is shown that the present calorimeter, when operated in the relaxation mode, enables detection of the latent heat with a resolution of 0.002 J/g.

  16. The ac Josephson effect: observation of electromagnetic radiation (Review)

    NASA Astrophysics Data System (ADS)

    Yanson, I. K.

    2004-07-01

    An historical review of the discovery and the early period of research on the Josephson effect is given. Experiments on the tunneling effect in superconductors done in the 1960s at the Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Kharkov (ILTPE), which led to the observation of Josephson electromagnetic radiation are described in detail. The experimental data are illustrated by the original curves, and the dates they were taken are indicated. The physical mechanism for the generation of rf radiation in superconducting tunnel junctions is examined, and some of the more promising applications of the ac Josephson effect are briefly listed.

  17. Topological Instabilities in ac-Driven Bosonic Systems

    NASA Astrophysics Data System (ADS)

    Engelhardt, G.; Benito, M.; Platero, G.; Brandes, T.

    2016-07-01

    Under nonequilibrium conditions, bosonic modes can become dynamically unstable with an exponentially growing occupation. On the other hand, topological band structures give rise to symmetry protected midgap states. In this Letter, we investigate the interplay of instability and topology. Thereby, we establish a general relation between topology and instability under ac driving. We apply our findings to create dynamical instabilities which are strongly localized at the boundaries of a finite-size system. As these localized instabilities are protected by symmetry, they can be considered as topological instabilities.

  18. Fast recovery, high voltage silicon diodes for AC motor controllers

    NASA Technical Reports Server (NTRS)

    Balodis, V.; Berman, A. H.; Gaugh, C.

    1982-01-01

    The fabrication and characterization of a high voltage, high current, fast recovery silicon diode for use in AC motor controllers, originally developed for NASA for use in avionics power supplies, is presented. The diode utilizes a positive bevel PIN mesa structure with glass passivation and has the following characteristics: peak inverse voltage - 1200 volts, forward voltage at 50 amperes - 1.5 volts, reverse recovery time of 200 nanoseconds. Characterization data for the diode, included in a table, show agreement with design concepts developed for power diodes. Circuit diagrams of the diode are also given.

  19. STIS-ACS Red Leak Cross-Calibration

    NASA Astrophysics Data System (ADS)

    Chiaberge, Marco

    2009-07-01

    We observe one type K star {G Gem} with ACS/SBC and STIS in order to determine the throughput in the red leak of both the SBC and the STIS FUV-MAMA. We will also observe the type G9V star HD53143 with the SBC with all long-pass filters and the PR130L in order to compare the observed fluxes and the spectrum with a previous prism observation of the same star and investigate the possible time dependence of the red leak.

  20. Glutathione preconditioning attenuates Ac-LDL-induced macrophage apoptosis via protein kinase C-dependent Ac-LDL trafficking.

    PubMed

    Rosenson-Schloss, Rene S; Chnari, Evangelia; Brieva, Thomas A; Dang, Anh; Moghe, Prabhas V

    2005-01-01

    Oxidized low-density lipoprotein (ox-LDL) incorporation into intimally resident vascular cells via scavenger receptors marks one of the early steps in atherosclerosis. Cellular apoptotic damage results from two major serial intracellular events: the binding and scavenger receptor-mediated uptake of oxidizable lipoproteins and the intracellular oxidative responses of accumulated lipoproteins. Most molecular approaches to prevent apoptotic damage have focused on singular events within the cascade of lipoprotein trafficking. To identify a multifocal strategy against LDL-induced apoptosis, we evaluated the role of cellular preconditioning by glutathione-ethyl ester (GSH-Et), a native redox regulator, in the prevention of the uptake and apoptotic effects of an oxidizable scavenger receptor-specific ligand, acetylated low-density lipoprotein (Ac-LDL). Our results indicate that GSH-Et-mediated protein kinase C (PKC) pathway modulation regulates Ac-LDL binding and incorporation into GSH-Et preconditioned cells and subsequently delays reactive oxygen intermediate generation and apoptotic conversion. The GSH-Et protective effects on apoptosis and Ac-LDL binding were reversed by calphostin C, a PKC inhibitor, and were accompanied by an increase in PKC phosphorylation. However, the rate of reactive oxygen intermediate accumulation was not increased following calphostin C treatment, suggesting that GSH-Et may play an important nonreactive oxygen-intermediate-based protective role in regulating apoptotic dynamics. Overall, we report on the novel role for GSH-Et preconditioning as a molecular strategy to limit lipoprotein entry into the cells, which presents a proactive modality to prevent cellular apoptosis in contrast with the prevalent antioxidant approaches that treat damage retroactively. PMID:15618124

  1. Optoelectrofluidic field separation based on light-intensity gradients and its applications

    NASA Astrophysics Data System (ADS)

    Yoon, Jinsung; Lee, Sanghyun; Kang, Kwan Hyoung

    2010-11-01

    Optoelectrofluidic field separation (OEFS) of particles under light-intensity gradient (LIG) is reported, where the LIG illumination on the photoconductive layer converts the short-ranged dielectrophoresis (DEP) force to the long-ranged one. The long-ranged DEP force can compete with the hydrodynamic force by alternating current electro-osmosis (ACEO) over the entire illumination area for realizing effective field separation of particles. Results of the field separation and concentration of diverse particle pairs (0.82--16 μm) are well demonstrated, and conditions determining the critical radius and effective particle manipulation are discussed. In addition, expanding the OEFS to biological applications such as rapid cell manipulation and separation will be discussed. The OEFS with LIG strategy could be a promising manipulation method of particles including biological cells in many applications where a rapid manipulation of particles over the entire working area is of interest.

  2. System and method for determining stator winding resistance in an AC motor

    DOEpatents

    Lu, Bin; Habetler, Thomas G.; Zhang, Pinjia; Theisen, Peter J.

    2011-05-31

    A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch to control current flow and terminal voltages in the AC motor. The system also includes a controller connected to the circuit and configured to modify a switching time of the at least one switch to create a DC component in an output of the system corresponding to an input to the AC motor and determine a stator winding resistance of the AC motor based on the injected DC component of the voltage and current.

  3. Ac vortex-dependent torsional oscillation response and onset temperature T0 in solid 4He.

    PubMed

    Penzev, Andrey; Yasuta, Yoshinori; Kubota, Minoru

    2008-08-01

    Detailed studies of ac velocity V_{ac} and T dependence of torsional oscillator responses of solid 4He are reported. A characteristic onset temperature T_{0} approximately 0.5 K is found, below which a significant V_{ac}-dependent change occurs in the energy dissipation for the samples at approximately 32 bar and for one at 49 bar. A V_{ac} dependence of the so-called "nonclassical rotational inertia" fraction also appears below approximately T_{0}. The log(V_{ac}) linear dependence, which suggests involvement of quantized vorticies, was examined in the nonclassical rotational inertia fraction. We find a common 1/T;{2} dependence for this linear slope change in all of the samples for 30ac}<300 microm/s. We discuss that our observation is consistent with nonlinear rotational susceptibility of the vortex fluid, proposed by Anderson above T_{c} below T0. PMID:18764467

  4. Resonant tunneling of interacting electrons in an AC electric field

    SciTech Connect

    Elesin, V. F.

    2013-11-15

    The problem of the effect of electron-electron interaction on the static and dynamic properties of a double-barrier nanostructure (resonant tunneling diode (RTD)) is studied in terms of a coherent tunneling model, which includes a set of Schrödinger and Poisson equations with open boundary conditions. Explicit analytical expressions are derived for dc and ac potentials and reduced (active and reactive) currents in the quasi-classical approximation over a wide frequency range. These expressions are used to analyze the frequency characteristics of RTD. It is shown that the interaction can radically change the form of these expressions, especially in the case of a hysteretic I-V characteristic. In this case, the active current and the ac potentials can increase sharply at both low and high frequencies. For this increase to occur, it is necessary to meet quantum regime conditions and to choose a proper working point in the I-V characteristic of RTD. The possibility of appearance of specific plasma oscillations, which can improve the high-frequency characteristics of RTD, is predicted. It is found that the active current can be comparable with the resonant dc current of RTD.

  5. Mechanism for AC Electric Field Deflection of Flames

    NASA Astrophysics Data System (ADS)

    Chemama, Michael; Bishop, Kyle; Cademartiri, Ludovico; Brenner, Michael P.; Whitesides, Georges M.

    2010-11-01

    Effects of electric fields on flames have been observed and studied since the 19th century. It is well known that the presence of an electric field can modify the shape of a burner or candle-like diffusion flame. Most experimental observations and theoretical analyses focused on DC fields. Recent experiments show that a flame can also be bent and even put out by an AC field. To explain how a zero time average cause can give rise to a net effect on the flame we develop a perturbation theory of the combustion equations modified to allow for the presence of the field and completed by Maxwell's equation. Theoretical and numerical analyses of the equations indeed show that the AC field creates a force whose magnitude is comparable to gravity for high enough fields (1e5 V/m). The dependency of this critical field on the frequency and the effect on the flame shape are also obtained and compared to experimental results.

  6. ACS after SM4: New Life for an Old Workhorse

    NASA Astrophysics Data System (ADS)

    Golimowski, David; Anderson, Jay; Armstrong, Amber; Arslanian, Steve; Bedin, Luigi; Bohlin, Ralph; Boyce, Kevin; Chapman, George; Cheng, Edward; Chiaberge, Marco; Cox, Colin; Desiardins, Tyler; Dye, Darryl; Ellis, Tracy; Ferguson, Brian; Fruchter, Andrew; Grogin, Norman; Lim, Pey Lian; Loose, Markus; Lucas, Ray; Lupie, Olivia; Mack, Jennifer; Maybhate, Aparna; Mil, Kathleen; Mutchler, Max; Ricardo, Raphael; Scott, Barbara; Serrano, Beverly; Sirianni, Marco; Smith, Linda; Suchkov, Anatoly A.; Waczynski, Augustyn; Welty, Alan; Wheeler, Thomas; Wilson, Erin

    2010-07-01

    The ACS CCD Electronics Box Replacement (CEB-R) installed during SM4 features a Teledyne SIDECAR ASIC that permits optimization of the WFC via adjustment of CCD clock voltages, bias voltages, and pixel transmission timing. An on-orbit campaign to optimize the performance of the WFC was undertaken at the start of the SMOV period. Initial tests with pre-SM4 default voltages and timing patterns showed that WFC's performance matches or exceeds its pre-failure levels, notwithstanding the expected increases in dark current and hot pixels and the decline in charge-transfer efficiency due to prolonged exposure to HST's radiation environment. One WFC CCD exhibited anomalous behavior when operated with nondefault settings of its reset drain voltage. Consequently, the optimization campaign was truncated after two iterations, and ACS science operations commenced with the pre-SM4 default configuration. Several artifacts attributed to the CEB-R appear in post-SM4 WFC images: large-scale but stable bias gradients, low-level but temporally variable horizontal stripes, a signal-dependent bias shift, and amplifier crosstalk. STScI has developed algorithms for the correction or mitigation of these electronic artifacts as well as for the restoration of images affected by continuously degrading CTE. Standalone correction packages are now or will soon be publicly available. These packages will be incorporated into the calacs package of the OPUS data pipeline by September 2011.

  7. ACS after Servicing Mission 4: The WFC Optimization Campaign

    NASA Astrophysics Data System (ADS)

    Golimowski, David; Cheng, Ed; Loose, Markus; Sirianni, Marco; Lupie, Olivia; Smith, Linda; Arslanian, Steve; Boyce, Kevin; Chapman, George; Chiaberge, Marco; Desjardins, Tyler; Dye, Darryl; Grogin, Norman; Lim, Pey Lian; Lucas, Ray; Maybhate, Aparna; Mil, Kathleen; Mutchler, Max; Ricardo, Raphael; Scott, Barbara; Serrano, Beverly; Suchkov, Anatoly; Waczynski, Augustyn; Welty, Alan; Wheeler, Thomas; Wilson, Erin

    2011-07-01

    The ACS CCD Electronics Box Replacement (CEB-R) installed during SM4 features a Teledyne SIDECAR ASIC that permits optimization of the WFC via adjustment of CCD clock voltages, bias voltages, and pixel transmission timing. A built-in oscilloscope mode allows sensing of the analog signal from each output amplifier. An on-orbit campaign to optimize the performance of the WFC was undertaken at the start of the SMOV period. Initial tests with pre-SM4 default voltages and timing patterns showed that WFC's performance matches or exceeds its pre-failure levels, notwithstanding the expected increases in dark current and hot pixels and the decline in charge-transfer efficiency due to prolonged exposure to HST's radiation environment. The WFC2 CCD exhibited anomalous behavior when operated with nondefault settings of its amplifiers' reset-drain voltage (VOD). The CCD again displayed normal behavior when VOD was restored to its default setting. Consequently, the Optimization Campaign was truncated after two iterations, and ACS science operations commenced with the pre-SM4 default configuration.

  8. Input current shaped ac-to-dc converters

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Input current shaping techniques for ac-to-dc converters were investigated. Input frequencies much higher than normal, up to 20 kHz were emphasized. Several methods of shaping the input current waveform in ac-to-dc converters were reviewed. The simplest method is the LC filter following the rectifier. The next simplest method is the resistor emulation approach in which the inductor size is determined by the converter switching frequency and not by the line input frequency. Other methods require complicated switch drive algorithms to construct the input current waveshape. For a high-frequency line input, on the order of 20 kHz, the simple LC cannot be discarded so peremptorily, since the inductor size can be compared with that for the resistor emulation method. In fact, since a dc regulator will normally be required after the filter anyway, the total component count is almost the same as for the resistor emulation method, in which the filter is effectively incorporated into the regulator.

  9. ACS sampling system: design, implementation, and performance evaluation

    NASA Astrophysics Data System (ADS)

    Di Marcantonio, Paolo; Cirami, Roberto; Chiozzi, Gianluca

    2004-09-01

    By means of ACS (ALMA Common Software) framework we designed and implemented a sampling system which allows sampling of every Characteristic Component Property with a specific, user-defined, sustained frequency limited only by the hardware. Collected data are sent to various clients (one or more Java plotting widgets, a dedicated GUI or a COTS application) using the ACS/CORBA Notification Channel. The data transport is optimized: samples are cached locally and sent in packets with a lower and user-defined frequency to keep network load under control. Simultaneous sampling of the Properties of different Components is also possible. Together with the design and implementation issues we present the performance of the sampling system evaluated on two different platforms: on a VME based system using VxWorks RTOS (currently adopted by ALMA) and on a PC/104+ embedded platform using Red Hat 9 Linux operating system. The PC/104+ solution offers, as an alternative, a low cost PC compatible hardware environment with free and open operating system.

  10. 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

  11. Revisiting the Mode-Beating Model of AC Helicity Injection

    NASA Astrophysics Data System (ADS)

    Sauppe, J. P.; Sovinec, C. R.

    2010-11-01

    Oscillating field current drive (OFCD), or AC helicity injection, is an important candidate for current sustainment in reversed-field pinch devices. Bellan examined AC helicity injection in a slab geometry and described it as a beating between two plasma modes that produces a mean current parallel to the equilibrium magnetic field [P. M. Bellan. Phys. Rev. Lett. 54, 1381 (1985)]. This mean current is confined to within a classical resistive skin depth of the plasma surface, and plasma relaxation is responsible for transporting this current to the core. We revisit this analytical work and examine how this wave-beating effect is represented in zero-beta MHD simulations, including consideration of the choice of boundary conditions. In addition to the expected parallel current, numerical simulations show a pinch effect from a cycle-averaged current that is perpendicular to the mean magnetic field, which is not described in Bellan's original work. Our results are discussed with respect to Boozer's general anti-dynamo theorem [A. H. Boozer. Phys. Fluids B Vol. 5, 2271 (1993)].

  12. 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

  13. AcsD catalyzes enantioselective citrate desymmetrization in siderophore biosynthesis.

    PubMed

    Schmelz, Stefan; Kadi, Nadia; McMahon, Stephen A; Song, Lijiang; Oves-Costales, Daniel; Oke, Muse; Liu, Huanting; Johnson, Kenneth A; Carter, Lester G; Botting, Catherine H; White, Malcolm F; Challis, Gregory L; Naismith, James H

    2009-03-01

    Bacterial pathogens need to scavenge iron from their host for growth and proliferation during infection. They have evolved several strategies to do this, one being the biosynthesis and excretion of small, high-affinity iron chelators known as siderophores. The biosynthesis of siderophores is an important area of study, not only for potential therapeutic intervention but also to illuminate new enzyme chemistries. Two general pathways for siderophore biosynthesis exist: the well-characterized nonribosomal peptide synthetase (NRPS)-dependent pathway and the NRPS-independent siderophore (NIS) pathway, which relies on a different family of sparsely investigated synthetases. Here we report structural and biochemical studies of AcsD from Pectobacterium (formerly Erwinia) chrysanthemi, an NIS synthetase involved in achromobactin biosynthesis. The structures of ATP and citrate complexes provide a mechanistic rationale for stereospecific formation of an enzyme-bound (3R)-citryladenylate, which reacts with L-serine to form a likely achromobactin precursor. AcsD is a unique acyladenylate-forming enzyme with a new fold and chemical catalysis strategy. PMID:19182782

  14. Enhanced apparatus for AC Zeeman experiments with ultracold potassium

    NASA Astrophysics Data System (ADS)

    Rotunno, Andrew; Du, Shuangli; Fancher, Charles; Pyle, Andrew; Aubin, Seth

    2016-05-01

    Ultracold atomic potassium is an excellent candidate for studies of the AC Zeeman force, due to small hyperfine splittings. These experiments require a sufficient sample of potassium near an atom chip supporting RF currents, and an RF source which can make rapid phase-continuous frequency sweeps for fast manipulation of spin states. We present progress on the construction of laser amplifier system for improved laser cooling and trapping of potassium, development of a frequency-agile RF source, and research on RF-capable atom chips. The laser amplifier system consists of two tapered amplifiers for producing 0.4 W of 767 nm light, with a goal of collecting 107 potassium atoms at 100 μK, which will then be cooled sympathetically with ultracold rubidium. We have constructed a direct digital synthesizer (DDS) to produce 1-400 MHz with Hz-level linewidth and noise level below -60dBc, and the ability to produce fast 100 μs frequency sweeps. We are investigating atom chip designs for supporting large RF currents. Immediate applications include AC Zeeman potentials and traps for atom interferometry, and quantum many-body physics. Work supported by AFOSR, W&M, and in part by AFRL.

  15. ac impedance measurements of molten salt thermal batteries

    NASA Astrophysics Data System (ADS)

    Singh, Pritpal; Guidotti, Ronald A.; Reisner c, David

    Non-destructive testing of thermal batteries without activating them is a challenging proposition. Molten salt thermal batteries are activated by raising their temperature to above the melting point of the salt constituting the electrolyte. One approach that we have considered is to raise the temperature of the molten salt electrolyte to a temperature below the melting point so that the battery does not get activated yet may provide sufficient mobility of the ionic species to be able to obtain some useful ac impedance measurements. This hypothesis was put to the test for two Li(Si)/FeS 2 molten salt batteries with two electrolytes of different melting points—a standard LiCl-KCl eutectic that melts at 352 °C and a LiBr-KBr-LiCl eutectic with a melting point of 319 °C. ac impedance measurements as a function of frequency and temperature below the melting point are presented for single cells and batteries.

  16. Perfecting the Photometric Calibration of the ACS CCD Cameras

    NASA Astrophysics Data System (ADS)

    Bohlin, Ralph C.

    2016-09-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the charge-coupled device cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC1 database for three primary hot 30,000–60,000K WDs define the sensitivity calibrations for the Wide Field Channel (WFC) and High Resolution Channel (HRC) filters. The external uncertainty for the absolute flux is ˜1%, while the internal consistency of the sensitivities in the broadband ACS filters is ˜0.3% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1% at the WFC1-1K subarray position, which achieves the 1% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1% precision goal is achieved over the full F814W WFC field of view for stars of K type and hotter. New encircled energies and absolute sensitivities replace the seminal results of Sirianni et al. that were published in 2005. After implementing the throughput updates, synthetic predictions of the WFC and HRC count rates for the average of the three primary WD standard stars agree with the observations to 0.1%.

  17. Offline detection of broken rotor bars in AC induction motors

    NASA Astrophysics Data System (ADS)

    Powers, Craig Stephen

    ABSTRACT. OFFLINE DETECTION OF BROKEN ROTOR BARS IN AC INDUCTION MOTORS. The detection of the broken rotor bar defect in medium- and large-sized AC induction machines is currently one of the most difficult tasks for the motor condition and monitoring industry. If a broken rotor bar defect goes undetected, it can cause a catastrophic failure of an expensive machine. If a broken rotor bar defect is falsely determined, it wastes time and money to physically tear down and inspect the machine only to find an incorrect diagnosis. Previous work in 2009 at Baker/SKF-USA in collaboration with the Korea University has developed a prototype instrument that has been highly successful in correctly detecting the broken rotor bar defect in ACIMs where other methods have failed. Dr. Sang Bin and his students at the Korea University have been using this prototype instrument to help the industry save money in the successful detection of the BRB defect. A review of the current state of motor conditioning and monitoring technology for detecting the broken rotor bar defect in ACIMs shows improved detection of this fault is still relevant. An analysis of previous work in the creation of this prototype instrument leads into the refactoring of the software and hardware into something more deployable, cost effective and commercially viable.

  18. Testing of a First Order AC Magnetic Susceptometer

    NASA Astrophysics Data System (ADS)

    Fukuda, Ryan; Sunny, Smitha; Ho, Pei-Chun

    2011-11-01

    A first-order AC magnetic susceptometer has been constructed and tested to find the magnetic response of strongly correlated electron materials. The instrument works by using a primary coil to apply a small AC magnetic field of .104 Oe to a sample with a cylindrical coil space of length .635 cm and diameter .355 cm. A lock-in amplifier is used to monitor the induced voltage from a set of secondary coils. By coupling a temperature-controlled system with this instrument, the change in the magnetic signal with respect to temperature is measured. Monitoring the signal changes may indicate the temperature that causes the material to transition to either a ferromagnetic, anti-ferromagnetic, or superconducting state. A 122.47 mg Gd polycrystal was used to test our susceptometer. The data qualitatively agrees with the previous results of magnetization vs. temperature of Gd single crystals by Nigh et al. [1]: there is a steep increase in the pick-up signal at 300 K where Gd becomes ferromagnetic and a peak at 210 K [1]. This susceptometer will be used for our future investigation of magnetic properties of rare earth compounds and nanoparticles in the temperature range of 10 K to 300 K. [4pt] [1] H. E. Nigh, S. Legvold, and F. H. Spedding, Physical Review 132, 1092 (1963)

  19. 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.

  20. 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.

  1. A driving scheme to reduce AC LED flicker

    NASA Astrophysics Data System (ADS)

    Tan, Jianchuan; Narendran, Nadarajah

    2013-09-01

    Light flicker is a common but unwelcome phenomenon in conventional lighting applications. In solid-state lighting, driving or dimming methods also give rise to light flicker. AC LED products in today's marketplace suffer from flicker, which stems from the arrangement of the micro-LEDs and the driving method. Research has shown that light flicker can be a health hazard to humans. Several solutions have been proposed to reduce light flicker in solid-state lighting applications; however, most have drawbacks in terms of power and other performance. This paper proposes a circuit design to reduce light flicker from AC LEDs while maintaining a normal power factor and high power efficiency. The circuit is composed of one resistive branch and one capacitive branch, and each branch drives a load which is made up of high-voltage LEDs. Percent flicker, power factor, and power efficiency were selected as three metrics, and their benchmarks were set to evaluate the performance of this circuit. Phase shift between the two branches was selected as a factor that could determine the circuit performance. The variations of percent flicker, power factor, and power efficiency as a function of phase shift were identified by theoretical analysis and were verified by experiments. The experimental results show that an optimal solution can be achieved for this circuit design at proper phase shift, where the benchmarks of the three metrics are reached.

  2. Perfecting the Photometric Calibration of the ACS CCD Cameras

    NASA Astrophysics Data System (ADS)

    Bohlin, Ralph C.

    2016-09-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the charge-coupled device cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC1 database for three primary hot 30,000-60,000K WDs define the sensitivity calibrations for the Wide Field Channel (WFC) and High Resolution Channel (HRC) filters. The external uncertainty for the absolute flux is ˜1%, while the internal consistency of the sensitivities in the broadband ACS filters is ˜0.3% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1% at the WFC1-1K subarray position, which achieves the 1% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1% precision goal is achieved over the full F814W WFC field of view for stars of K type and hotter. New encircled energies and absolute sensitivities replace the seminal results of Sirianni et al. that were published in 2005. After implementing the throughput updates, synthetic predictions of the WFC and HRC count rates for the average of the three primary WD standard stars agree with the observations to 0.1%.

  3. New Sky Flats for HST's ACS/WFC

    NASA Astrophysics Data System (ADS)

    Lucas, Ray A.; Grogin, Norman A.

    2016-06-01

    We have begun experiments to make new sky flat files for HST's ACS/WFC. Sky flats can be especially useful for deep imaging in such as programs as deep, extragalactic survey programs because they can help to better deal with noise at low levels. Although we also hope to make similar sky flats for some other popular filters including F606W and F814W, we are beginning this experiment with the F435W filter on the ACS/WFC since it is a popular filter in use in many deep extragalactic surveys, and since the bluer filters such as F435W generally have lower throughput and images in that filter are typically noisier than others at some longer mid-optical wavelengths. Initially, although sources will be masked in these images, etc. we are endeavoring to use just post-SM4 F435W images of duration equal to or greater than 800 seconds and which are free of bright stars in order to try and avoid scattered light and sky background color issues as much as possible, although the sky in different images taken at different times and in different directions will likely have some different background levels and color terms in any event. However, our hope is that the final sky flats will be of sufficient S/N to be good calibrators for deep survey programs.

  4. 26 CFR 1.613A-5 - Election under section 613A(c)(4).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 7 2011-04-01 2009-04-01 true Election under section 613A(c)(4). 1.613A-5... TAX (CONTINUED) INCOME TAXES (CONTINUED) Natural Resources § 1.613A-5 Election under section 613A(c)(4). The election under section 613A(c)(4) is an annual election which the taxpayer may make by...

  5. 26 CFR 1.613A-5 - Election under section 613A(c)(4).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 7 2010-04-01 2010-04-01 true Election under section 613A(c)(4). 1.613A-5 Section 1.613A-5 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Natural Resources § 1.613A-5 Election under section 613A(c)(4). The election under section 613A(c)(4) is...

  6. Programmable AC power supply for simulating power transient expected in fusion reactor

    SciTech Connect

    Halimi, B.; Suh, K. Y.

    2012-07-01

    This paper focus on control engineering of the programmable AC power source which has capability to simulate power transient expected in fusion reactor. To generate the programmable power source, AC-AC power electronics converter is adopted to control the power of a set of heaters to represent the transient phenomena of heat exchangers or heat sources of a fusion reactor. The International Thermonuclear Experimental Reactor (ITER) plasma operation scenario is used as the basic reference for producing this transient power source. (authors)

  7. TCE TRANSPORT AND DEGRADATION IN SOIL USING ELECTROOSMOSIS

    EPA Science Inventory

    Laboratory experiments were used to characterize the transport and chemical transformation of TCE in undisturbed soil cores. Electroosmotic fluid flow was vertically downwards from anode to cathode. A voltage of 1.4 V/cm was applied to the soil for 4 weeks. More than 95% of the T...

  8. Drying characteristics of electro-osmosis dewatered sludge.

    PubMed

    Ma, Degang; Qian, Jingjing; Zhu, Hongmin; Zhai, Jun

    2016-12-01

    Electro-osmotic dewatering (EDW) is one of the effective deeply dewatering technologies that is suitable for treating sludge with 55-80% of moisture content. Regarding EDW as the pre-treatment process of drying or incinerating, this article investigated the drying characteristics of electro-osmosis-dewatered sludge, including shear stress test, drying curves analysis, model analysis, and energy balance calculation. After EDW pre-treatment, sludge adhesion was reduced. The sludge drying rate was higher compared to the non-pre-treated sludge, especially under high temperatures (80-120°C). In addition, it is better to place the sludge cake with cathode surface facing upward for improving the drying rate. An adjusted model based on the Logarithmic model could better describe the EDW sludge drying process. Using the energy balance calculation, EDW can save the energy consumed in the process of sludge incineration and electricity generation and enable the system to run without extra energy input. PMID:27063252

  9. 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.

  10. 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

  11. An H2A Histone Isotype, H2ac, Associates with Telomere and Maintains Telomere Integrity

    PubMed Central

    Tzeng, Tsai-Yu; Lin, I-Hsuan; Hsu, Ming-Ta

    2016-01-01

    Telomeres are capped at the ends of eukaryotic chromosomes and are composed of TTAGGG repeats bound to the shelterin complex. Here we report that a replication-dependent histone H2A isotype, H2ac, was associated with telomeres in human cells and co-immunoprecipitates with telomere repeat factor 2 (TRF2) and protection of telomeres protein 1 (POT1), whereas other histone H2A isotypes and mutations of H2ac did not bind to telomeres or these two proteins. The amino terminal basic domain of TRF2 was necessary for the association with H2ac and for the recruitment of H2ac to telomeres. Depletion of H2ac led to loss of telomeric repeat sequences, the appearance of dysfunctional telomeres, and chromosomal instability, including chromosomal breaks and anaphase bridges, as well as accumulation of telomere-associated DNA damage factors in H2ac depleted cells. Additionally, knockdown of H2ac elicits an ATM-dependent DNA damage response at telomeres and depletion of XPF protects telomeres against H2ac-deficiency-induced G-strand overhangs loss and DNA damage response, and prevents chromosomal instability. These findings suggest that the H2A isotype, H2ac, plays an essential role in maintaining telomere functional integrity. PMID:27228173

  12. 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.

  13. Orthogonal-core type three-phase dc-ac converter

    SciTech Connect

    Ichinokura, O.; Saito, H.; Jinzenji, T. ); Tajima, K. )

    1993-03-01

    In a previous paper, the authors proposed an orthogonal-core type dc-ac converter for use in photovoltaic power systems. The dc-ac converter has such desirable features as a simple construction, high degree of safety, and ease of maintenance. The operating characteristics of a single-phase converter for residential photovoltaic power systems have also been reported. In this paper, the authors discuss the basic operation of an orthogonal-core type dc-ac converter for a three-phase power system based on simulations and experiments. An optimal construction of the orthogonal-core type three-phase dc-ac converter has been developed.

  14. ac18 is not essential for the propagation of Autographa californica multiple nucleopolyhedrovirus

    SciTech Connect

    Wang Yanjie; Wu Wenbi; Li Zhaofei; Yuan Meijin; Feng Guozhong; Yu Qian; Yang Kai Pang Yi

    2007-10-10

    orf18 (ac18) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly conserved gene in lepidopteran nucleopolyhedroviruses, but its function remains unknown. In this study, an ac18 knockout AcMNPV bacmid was generated to determine the role of ac18 in baculovirus life cycle. After transfection of Sf-9 cells, the ac18-null mutant showed similar infection pattern to the parent virus and the ac18 repair virus with respect to the production of infectious budded virus, occlusion bodies, or the formation of nucleocapsids as visualized by electron microscopy. The deletion mutant did not reduce AcMNPV infectivity for Trichoplusia ni in LD{sub 50} bioassay; however, it did take 24 h longer for deleted mutant to kill T. ni larvae than wild-type virus in LT{sub 50} bioassay. Our results demonstrate that ac18 is not essential for viral propagation both in vitro and in vivo, but it may play a role in efficient virus infection in T. ni larvae.

  15. Autographa californica multiple nucleopolyhedrovirus ac142, a core gene that is essential for BV production and ODV envelopment

    SciTech Connect

    McCarthy, Christina B.; Da, Xiaojiang; Donly, Cam; Theilmann, David A.

    2008-03-15

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac142 is a baculovirus core gene and encodes a protein previously shown to associate with occlusion-derived virus (ODV). To determine its role in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac142 deletion virus (AcBAC{sup ac142KO-PH-GFP}). Fluorescence and light microscopy revealed that AcBAC{sup ac142KO-PH-GFP} exhibits a single-cell infection phenotype. Titration assays and Western blot confirmed that AcBAC{sup ac142KO-PH-GFP} is unable to produce budded virus (BV). However, viral DNA replication is unaffected and the development of occlusion bodies in AcBAC{sup ac142KO-PH-GFP}-transfected cells evidenced progression to very late phases of the viral infection. Western blot analysis showed that AC142 is expressed in the cytoplasm and nucleus throughout infection and that it is a structural component of BV and ODV which localizes to nucleocapsids. Electron microscopy indicates that ac142 is required for nucleocapsid envelopment to form ODV and their subsequent occlusion, a fundamental process to all baculoviruses.

  16. Autographa californica multiple nucleopolyhedrovirus ac142, a core gene that is essential for BV production and ODV envelopment.

    PubMed

    McCarthy, Christina B; Dai, Xiaojiang; Donly, Cam; Theilmann, David A

    2008-03-15

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac142 is a baculovirus core gene and encodes a protein previously shown to associate with occlusion-derived virus (ODV). To determine its role in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac142 deletion virus (AcBAC(ac142KO-PH-GFP)). Fluorescence and light microscopy revealed that AcBAC(ac142KO-PH-GFP) exhibits a single-cell infection phenotype. Titration assays and Western blot confirmed that AcBAC(ac142KO-PH-GFP) is unable to produce budded virus (BV). However, viral DNA replication is unaffected and the development of occlusion bodies in AcBAC(ac142KO-PH-GFP)-transfected cells evidenced progression to very late phases of the viral infection. Western blot analysis showed that AC142 is expressed in the cytoplasm and nucleus throughout infection and that it is a structural component of BV and ODV which localizes to nucleocapsids. Electron microscopy indicates that ac142 is required for nucleocapsid envelopment to form ODV and their subsequent occlusion, a fundamental process to all baculoviruses.

  17. Lack of mucin MUC5AC field change expression associated with tubulovillous and villous colorectal adenomas

    PubMed Central

    Longman, R; Douthwaite, J; Sylvester, P; O'Leary, D; Warren, B; Corfield, A; Thomas, M

    2000-01-01

    Background—MUC5AC is a secreted mucin aberrantly expressed by polypoid colorectal adenomas. It has been hypothesised that the "normal" surrounding colorectal mucosa expresses MUC5AC as a field change phenomenon that can be used to predict adenoma recurrence following resection. Aim—To determine if there is a field change of de novo MUC5AC expression in histologically normal rectal mucosa adjacent to villous and tubulovillous adenomas, and thus whether MUC5AC expression can be used as a marker of early tumour recurrence. Methods—In a prospective cohort study paired mucosal biopsies of adenomatous and macroscopically "normal" mucosa were obtained from 11 patients with villous and 11 patients with tubulovillous adenomas who underwent primary resection for purpose of cure. The tissues were studied to determine MUC5AC gene expression by immunohistochemistry and in situ hybridisation. Patients were followed up by flexible sigmoidoscopy to detect the presence of early local recurrence. Results—10 villous adenomas showed mature MUC5AC glycoprotein and all 11 expressed MUC5AC mRNA. Five tubulovillous adenomas showed mature MUC5AC glycoprotein and 10 expressed MUC5AC mRNA. Neoexpression of the MUC5AC mucin gene was not detected in any of the mucosal biopsies taken adjacent to either villous or tubulovillous adenomas, even in three patients with early, locally recurrent disease. Conclusions—Aberrant MUC5AC gene expression is not a "field change" in the colorectal mucosa in patients with rectal adenomas and therefore cannot be used to predict local recurrence of villous and tubulovillous adenomas. Key Words: mucin • colorectal adenoma • gene expression • field change PMID:10767823

  18. Age-related changes in lamin A/C expression in cardiomyocytes.

    PubMed

    Afilalo, Jonathan; Sebag, Igal A; Chalifour, Lorraine E; Rivas, Daniel; Akter, Rahima; Sharma, Kamal; Duque, Gustavo

    2007-09-01

    Lamin A and C (A/C) are type V intermediate filaments that form the nuclear lamina. Lamin A/C mutations lead to reduced expression of lamin A/C and diverse phenotypes such as familial cardiomyopathies and accelerated aging syndromes. Normal aging is associated with reduced expression of lamin A/C in osteoblasts and dermal fibroblasts but has never been assessed in cardiomyocytes. Our objective was to compare the expression of lamin A/C in cardiomyocytes of old (24 mo) versus young (4 mo) C57Bl/6J mice using a well-validated mouse model of aging. Lamin B1 was used as a control. Immunohistochemical and immunofluorescence analyses showed reduced expression of lamin A/C in cardiomyocyte nuclei of old mice (proportion of nuclei expressing lamin A/C, 9% vs. 62%, P < 0.001). Lamin A/C distribution was scattered peripherally and perinuclear in old mice, whereas it was homogeneous throughout the nuclei in young mice. Western blot analyses confirmed reduced expression of lamin A/C in nuclear extracts of old mice (ratio of lamin A/C to B1, 0.6 vs. 1.2, P < 0.01). Echocardiographic studies showed increased left ventricular wall thickness with preserved cavity size (concentric remodeling), increased left ventricular mass, and a slight reduction in fractional shortening in old mice. This is the first study to show that normal aging is associated with reduced expression and altered distribution of lamin A/C in nuclei of cardiomyocytes.

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  20. Resistojet control and power for high frequency ac buses

    NASA Technical Reports Server (NTRS)

    Gruber, Robert P.

    1987-01-01

    Resistojets are operational on many geosynchronous communication satellites which all use dc power buses. Multipropellant resistojets were selected for the Initial Operating Capability (IOC) Space Station which will supply 208 V, 20 kHz power. This paper discusses resistojet heater temperature controllers and passive power regulation methods for ac power systems. A simple passive power regulation method suitable for use with regulated sinusoidal or square wave power was designed and tested using the Space Station multipropellant resistojet. The breadboard delivered 20 kHz power to the resistojet heater. Cold start surge current limiting, a power efficiency of 95 percent, and power regulation of better than 2 percent were demonstrated with a two component, 500 W breadboard power controller having a mass of 0.6 kg.