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Sample records for pulsed electrically detected

  1. High resolution in-operando microimaging of solar cells with pulsed electrically-detected magnetic resonance

    Science.gov (United States)

    Katz, Itai; Fehr, Matthias; Schnegg, Alexander; Lips, Klaus; Blank, Aharon

    2015-02-01

    The in-operando detection and high resolution spatial imaging of paramagnetic defects, impurities, and states becomes increasingly important for understanding loss mechanisms in solid-state electronic devices. Electron spin resonance (ESR), commonly employed for observing these species, cannot meet this challenge since it suffers from limited sensitivity and spatial resolution. An alternative and much more sensitive method, called electrically-detected magnetic resonance (EDMR), detects the species through their magnetic fingerprint, which can be traced in the device's electrical current. However, until now it could not obtain high resolution images in operating electronic devices. In this work, the first spatially-resolved electrically-detected magnetic resonance images (EDMRI) of paramagnetic states in an operating real-world electronic device are provided. The presented method is based on a novel microwave pulse sequence allowing for the coherent electrical detection of spin echoes in combination with powerful pulsed magnetic-field gradients. The applicability of the method is demonstrated on a device-grade 1-μm-thick amorphous silicon (a-Si:H) solar cell and an identical device that was degraded locally by an electron beam. The degraded areas with increased concentrations of paramagnetic defects lead to a local increase in recombination that is mapped by EDMRI with ∼20-μm-scale pixel resolution. The novel approach presented here can be widely used in the nondestructive in-operando three-dimensional characterization of solid-state electronic devices with a resolution potential of less than 100 nm.

  2. Pulsed electric fields

    Science.gov (United States)

    The concept of pulsed electric fields (PEF) was first proposed in 1967 to change the behavior or microorganisms. The electric field phenomenon was identified as membrane rupture theory in the 1980s. Increasing the membrane permeability led to the application of PEF assisted extraction of cellular co...

  3. Detection and removal of impurities in nitric oxide generated from air by pulsed electrical discharge.

    Science.gov (United States)

    Yu, Binglan; Blaesi, Aron H; Casey, Noel; Raykhtsaum, Grigory; Zazzeron, Luca; Jones, Rosemary; Morrese, Alexander; Dobrynin, Danil; Malhotra, Rajeev; Bloch, Donald B; Goldstein, Lee E; Zapol, Warren M

    2016-11-30

    Inhalation of nitric oxide (NO) produces selective pulmonary vasodilation without dilating the systemic circulation. However, the current NO/N 2 cylinder delivery system is cumbersome and expensive. We developed a lightweight, portable, and economical device to generate NO from air by pulsed electrical discharge. The objective of this study was to investigate and optimize the purity and safety of NO generated by this device. By using low temperature streamer discharges in the plasma generator, we produced therapeutic levels of NO with very low levels of nitrogen dioxide (NO 2 ) and ozone. Despite the low temperature, spark generation eroded the surface of the electrodes, contaminating the gas stream with metal particles. During prolonged NO generation there was gradual loss of the iridium high-voltage tip (-90 μg/day) and the platinum-nickel ground electrode (-55 μg/day). Metal particles released from the electrodes were trapped by a high-efficiency particulate air (HEPA) filter. Quadrupole mass spectroscopy measurements of effluent gas during plasma NO generation showed that a single HEPA filter removed all of the metal particles. Mice were exposed to breathing 50 parts per million of electrically generated NO in air for 28 days with only a scavenger and no HEPA filter; the mice did not develop pulmonary inflammation or structural changes and iridium and platinum particles were not detected in the lungs of these mice. In conclusion, an electric plasma generator produced therapeutic levels of NO from air; scavenging and filtration effectively eliminated metallic impurities from the effluent gas. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Cryosurgery with pulsed electric fields.

    Directory of Open Access Journals (Sweden)

    Charlotte S Daniels

    Full Text Available This study explores the hypothesis that combining the minimally invasive surgical techniques of cryosurgery and pulsed electric fields will eliminate some of the major disadvantages of these techniques while retaining their advantages. Cryosurgery, tissue ablation by freezing, is a well-established minimally invasive surgical technique. One disadvantage of cryosurgery concerns the mechanism of cell death; cells at high subzero temperature on the outer rim of the frozen lesion can survive. Pulsed electric fields (PEF are another minimally invasive surgical technique in which high strength and very rapid electric pulses are delivered across cells to permeabilize the cell membrane for applications such as gene delivery, electrochemotherapy and irreversible electroporation. The very short time scale of the electric pulses is disadvantageous because it does not facilitate real time control over the procedure. We hypothesize that applying the electric pulses during the cryosurgical procedure in such a way that the electric field vector is parallel to the heat flux vector will have the effect of confining the electric fields to the frozen/cold region of tissue, thereby ablating the cells that survive freezing while facilitating controlled use of the PEF in the cold confined region. A finite element analysis of the electric field and heat conduction equations during simultaneous tissue treatment with cryosurgery and PEF (cryosurgery/PEF was used to study the effect of tissue freezing on electric fields. The study yielded motivating results. Because of decreased electrical conductivity in the frozen/cooled tissue, it experienced temperature induced magnified electric fields in comparison to PEF delivered to the unfrozen tissue control. This suggests that freezing/cooling confines and magnifies the electric fields to those regions; a targeting capability unattainable in traditional PEF. This analysis shows how temperature induced magnified and focused

  5. Cryosurgery with Pulsed Electric Fields

    Science.gov (United States)

    Daniels, Charlotte S.; Rubinsky, Boris

    2011-01-01

    This study explores the hypothesis that combining the minimally invasive surgical techniques of cryosurgery and pulsed electric fields will eliminate some of the major disadvantages of these techniques while retaining their advantages. Cryosurgery, tissue ablation by freezing, is a well-established minimally invasive surgical technique. One disadvantage of cryosurgery concerns the mechanism of cell death; cells at high subzero temperature on the outer rim of the frozen lesion can survive. Pulsed electric fields (PEF) are another minimally invasive surgical technique in which high strength and very rapid electric pulses are delivered across cells to permeabilize the cell membrane for applications such as gene delivery, electrochemotherapy and irreversible electroporation. The very short time scale of the electric pulses is disadvantageous because it does not facilitate real time control over the procedure. We hypothesize that applying the electric pulses during the cryosurgical procedure in such a way that the electric field vector is parallel to the heat flux vector will have the effect of confining the electric fields to the frozen/cold region of tissue, thereby ablating the cells that survive freezing while facilitating controlled use of the PEF in the cold confined region. A finite element analysis of the electric field and heat conduction equations during simultaneous tissue treatment with cryosurgery and PEF (cryosurgery/PEF) was used to study the effect of tissue freezing on electric fields. The study yielded motivating results. Because of decreased electrical conductivity in the frozen/cooled tissue, it experienced temperature induced magnified electric fields in comparison to PEF delivered to the unfrozen tissue control. This suggests that freezing/cooling confines and magnifies the electric fields to those regions; a targeting capability unattainable in traditional PEF. This analysis shows how temperature induced magnified and focused PEFs could be used to

  6. Pulsed electric field inactivation in a microreactor

    NARCIS (Netherlands)

    Fox, M.B.

    2006-01-01

    Pulsed electric fields (PEF) is a novel, non-thermal pasteurization method which uses short, high electric field pulses to inactivate microorganisms. The advantage of a pasteurization method like PEF compared to regular heat pasteurization is that the taste, flavour, texture and nutritional value

  7. Pulsed electric field increases reproduction.

    Science.gov (United States)

    Panagopoulos, Dimitris J

    2016-01-01

    Purpose To study the effect of pulsed electric field - applied in corona discharge photography - on Drosophila melanogaster reproduction, possible induction of DNA fragmentation, and morphological alterations in the gonads. Materials and methods Animals were exposed to different field intensities (100, 200, 300, and 400 kV/m) during the first 2-5 days of their adult lives, and the effect on reproductive capacity was assessed. DNA fragmentation during early- and mid-oogenesis was investigated by application of the TUNEL (Terminal deoxynucleotide transferase dUTP Nick End Labeling) assay. Sections of follicles after fixation and embedding in resins were observed for possible morphological/developmental abnormalities. Results The field increased reproduction by up to 30% by increasing reproductive capacity in both sexes. The effect increased with increasing field intensities. The rate of increase diminished at the strongest intensities. Slight induction of DNA fragmentation was observed exclusively in the nurse (predominantly) and follicle cells, and exclusively at the two most sensitive developmental stages, i.e., germarium and predominantly stage 7-8. Sections of follicles from exposed females at stages of early and mid-oogennesis other than germarium and stages 7-8 did not reveal abnormalities. Conclusions (1) The specific type of electric field may represent a mild stress factor, inducing DNA fragmentation and cell death in a small percentage of gametes, triggering the reaction of the animal's reproductive system to increase the rate of gametogenesis in order to compensate the loss of a small number of gametes. (2) The nurse cells are the most sensitive from all three types of egg chamber cells. (3) The mid-oogenesis checkpoint (stage 7-8) is more sensitive to this field than the early oogenesis one (germarium) in contrast to microwave exposure. (4) Possible therapeutic applications, or applications in increasing fertility, should be investigated.

  8. Moderate and high intensity pulsed electric fields

    OpenAIRE

    Timmermans, Rian Adriana Hendrika

    2018-01-01

    Pulsed Electric Field (PEF) processing has gained a lot of interest the last decades as mild processing technology as alternative to thermal pasteurisation, and is suitable for preservation of liquid food products such as fruit juices. PEF conditions typically applied at industrial scale for pasteurisation are high intensity pulsed electric fields aiming for minimal heat load, with an electric field strength (E) in the range of 15 − 20 kV/cm and pulse width (τ) between 2 − 20 μs. Alternativel...

  9. Electric fields in plasmas under pulsed currents

    International Nuclear Information System (INIS)

    Tsigutkin, K.; Doron, R.; Stambulchik, E.; Bernshtam, V.; Maron, Y.; Fruchtman, A.; Commisso, R. J.

    2007-01-01

    Electric fields in a plasma that conducts a high-current pulse are measured as a function of time and space. The experiment is performed using a coaxial configuration, in which a current rising to 160 kA in 100 ns is conducted through a plasma that prefills the region between two coaxial electrodes. The electric field is determined using laser spectroscopy and line-shape analysis. Plasma doping allows for three-dimensional spatially resolved measurements. The measured peak magnitude and propagation velocity of the electric field is found to match those of the Hall electric field, inferred from the magnetic-field front propagation measured previously

  10. Pulsed Electric Field treatment of packaged food

    NARCIS (Netherlands)

    Roodenburg, B.

    2011-01-01

    Food manufacturers are looking for new preservation techniques that don’t influence the fresh-like characteristics of products. Non-thermal pasteurisation of food with Pulsed Electric Fields (often referred to as PEF) is an emerging technology, where the change of the food is less than with thermal

  11. Moderate and high intensity pulsed electric fields

    NARCIS (Netherlands)

    Timmermans, Rian Adriana Hendrika

    2018-01-01

    Pulsed Electric Field (PEF) processing has gained a lot of interest the last decades as mild processing technology as alternative to thermal pasteurisation, and is suitable for preservation of liquid food products such as fruit juices. PEF conditions typically applied at industrial scale for

  12. Pulsed Electric Field treatment of packaged food

    OpenAIRE

    Roodenburg, B.

    2011-01-01

    Food manufacturers are looking for new preservation techniques that don’t influence the fresh-like characteristics of products. Non-thermal pasteurisation of food with Pulsed Electric Fields (often referred to as PEF) is an emerging technology, where the change of the food is less than with thermal pasteurisation. With this method, pasteurisation is realised by electroporation of bacterial membranes, which prolong the shelf-life of the product. Existing PEF treatment is based on the applicati...

  13. Electrical noise modulates perception of electrical pulses in humans: sensation enhancement via stochastic resonance.

    Science.gov (United States)

    Iliopoulos, Fivos; Nierhaus, Till; Villringer, Arno

    2014-03-01

    Although noise is usually considered to be harmful for signal detection and information transmission, stochastic resonance (SR) describes the counterintuitive phenomenon of noise enhancing the detection and transmission of weak input signals. In mammalian sensory systems, SR-related phenomena may arise both in the peripheral and the central nervous system. Here, we investigate behavioral SR effects of subliminal electrical noise stimulation on the perception of somatosensory stimuli in humans. We compare the likelihood to detect near-threshold pulses of different intensities applied on the left index finger during presence vs. absence of subliminal noise on the same or an adjacent finger. We show that (low-pass) noise can enhance signal detection when applied on the same finger. This enhancement is strong for near-threshold pulses below the 50% detection threshold and becomes stronger when near-threshold pulses are applied as brief trains. The effect reverses at pulse intensities above threshold, especially when noise is replaced by subliminal sinusoidal stimulation, arguing for a peripheral direct current addition. Unfiltered noise applied on longer pulses enhances detection of all pulse intensities. Noise applied to an adjacent finger has two opposing effects: an inhibiting effect (presumably due to lateral inhibition) and an enhancing effect (most likely due to SR in the central nervous system). In summary, we demonstrate that subliminal noise can significantly modulate detection performance of near-threshold stimuli. Our results indicate SR effects in the peripheral and central nervous system.

  14. Pulse Detecting Genetic Circuit – A New Design Approach

    Science.gov (United States)

    Inniss, Mara; Iba, Hitoshi; Way, Jeffrey C.

    2016-01-01

    A robust cellular counter could enable synthetic biologists to design complex circuits with diverse behaviors. The existing synthetic-biological counters, responsive to the beginning of the pulse, are sensitive to the pulse duration. Here we present a pulse detecting circuit that responds only at the falling edge of a pulse–analogous to negative edge triggered electric circuits. As biological events do not follow precise timing, use of such a pulse detector would enable the design of robust asynchronous counters which can count the completion of events. This transcription-based pulse detecting circuit depends on the interaction of two co-expressed lambdoid phage-derived proteins: the first is unstable and inhibits the regulatory activity of the second, stable protein. At the end of the pulse the unstable inhibitor protein disappears from the cell and the second protein triggers the recording of the event completion. Using stochastic simulation we showed that the proposed design can detect the completion of the pulse irrespective to the pulse duration. In our simulation we also showed that fusing the pulse detector with a phage lambda memory element we can construct a counter which can be extended to count larger numbers. The proposed design principle is a new control mechanism for synthetic biology which can be integrated in different circuits for identifying the completion of an event. PMID:27907045

  15. Comparison of pulsed corona plasma and pulsed electric fields for the decontamination of water containing Legionella pneumophila as model organism.

    Science.gov (United States)

    Banaschik, Robert; Burchhardt, Gerhard; Zocher, Katja; Hammerschmidt, Sven; Kolb, Juergen F; Weltmann, Klaus-Dieter

    2016-12-01

    Pulsed corona plasma and pulsed electric fields were assessed for their capacity to kill Legionella pneumophila in water. Electrical parameters such as in particular dissipated energy were equal for both treatments. This was accomplished by changing the polarity of the applied high voltage pulses in a coaxial electrode geometry resulting in the generation of corona plasma or an electric field. For corona plasma, generated by high voltage pulses with peak voltages of +80kV, Legionella were completely killed, corresponding to a log-reduction of 5.4 (CFU/ml) after a treatment time of 12.5min. For the application of pulsed electric fields from peak voltages of -80kV a survival of log 2.54 (CFU/ml) was still detectable after this treatment time. Scanning electron microscopy images of L. pneumophila showed rupture of cells after plasma treatment. In contrast, the morphology of bacteria seems to be intact after application of pulsed electric fields. The more efficient killing for the same energy input observed for pulsed corona plasma is likely due to induced chemical processes and the generation of reactive species as indicated by the evolution of hydrogen peroxide. This suggests that the higher efficacy and efficiency of pulsed corona plasma is primarily associated with the combined effect of the applied electric fields and the promoted reaction chemistry. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. An explanation for parallel electric field pulses observed over thunderstorms

    Science.gov (United States)

    Kelley, M. C.; Barnum, B. H.

    2009-10-01

    Every electric field instrument flown on sounding rockets over a thunderstorm has detected pulses of electric fields parallel to the Earth's magnetic field associated with every strike. This paper describes the ionospheric signatures found during a flight from Wallops Island, Virginia, on 2 September 1995. The electric field results in a drifting Maxwellian corresponding to energies up to 1 eV. The distribution function relaxes because of elastic and inelastic collisions, resulting in electron heating up to 4000-5000 K and potentially observable red line emissions and enhanced ISR electron temperatures. The field strength scales with the current in cloud-to-ground strikes and falls off as r -1 with distance. Pulses of both polarities are found, although most electric fields are downward, parallel to the magnetic field. The pulse may be the reaction of ambient plasma to a current pulse carried at the whistler packet's highest group velocity. The charge source required to produce the electric field is very likely electrons of a few keV traveling at the packet velocity. We conjecture that the current source is the divergence of the current flowing at mesospheric heights, the phenomenon called an elve. The whistler packet's effective radiated power is as high as 25 mW at ionospheric heights, comparable to some ionospheric heater transmissions. Comparing the Poynting flux at the base of the ionosphere with flux an equal distance away along the ground, some 30 db are lost in the mesosphere. Another 10 db are lost in the transition from free space to the whistler mode.

  17. Hemorrhage control by microsecond electrical pulses

    Science.gov (United States)

    Mandel, Yossi; Manivanh, Richard; Dalal, Roopa; Huie, Phil; Wang, Jenny; Brinton, Mark; Palanker, Daniel

    2013-02-01

    Non-compressible hemorrhages are the most common preventable cause of death on battlefield or in civilian traumatic injuries. We report the use of sub-millisecond pulses of electric current to induce rapid constriction in femoral and mesenteric arteries and veins in rats. Extent of vascular constriction could be modulated by pulse duration, amplitude and repetition rate. Electrically-induced vasoconstriction could be maintained at steady level until the end of stimulation, and blood vessels dilated back to their original size within a few minutes after the end of stimulation. At higher settings, a blood clotting could be introduced, leading to complete and permanent occlusion of the vessels. The latter regime dramatically decreased the bleeding rate in the injured femoral and mesenteric arteries, with a complete hemorrhage arrest achieved within seconds. The average blood loss from the treated femoral artery was about 7 times less than that of a non-treated control. This new treatment modality offers a promising approach to non-damaging control of bleeding during surgery, and to efficient hemorrhage arrest in trauma patients.

  18. Influence of pulsed electric field on defectoscopic characteristics of electro- x-ray radiography

    International Nuclear Information System (INIS)

    Gusev, E.A.; Lomonosov, V.V.; Sosnin, F.R.

    1988-01-01

    A new method to increase electric resistance of semiconductor plates in the process of electro-X-ray radiography, which is based on influence of a pulsed electric field on the plate semiconductor layer is suggested. The effect of a pulsed field with the intensity E=10 6 V/cm, frequency of 50 Hz and front length of 1 ns has increased electric resistance of the semiconductor layer and improved flaw detection in the process of electroradiography

  19. Pulse X-radiation in flaw detection

    International Nuclear Information System (INIS)

    Vavilov, S.P.; Gorbunov, V.I.

    1985-01-01

    Principles of physical and engineering application of pulse X-radiation (PXR) of micro- and nanosecond duration for nondestructive testing of processes, materials and devices are given. Methods and devices, aimed at generating X-ray pulses, as well as their radiation and flow detection characteristics, and testing methods by means of PXR are considered

  20. The detection and estimation of spurious pulses

    International Nuclear Information System (INIS)

    1976-01-01

    Spurious pulses which may interfere with the counting of particles can sometimes easily be detected by integral counting as a function of amplification or by pulse-height analysis. However, in order to estimate their count rate, more elaborate methods based on their time relationship are needed. Direct techniques (delayed coincidences, use of a multichannel analyser in time mode, time-to-amplitude conversion) and gating techniques (simple subtraction, correlation counting, pulsed sources, modulo counting) are discussed. These techniques are compared to each other and their application to various detectors is studied as well as the influence of a dead time on spurious pulses

  1. Detection of SNM by Pulsed Neutron Interrogation

    International Nuclear Information System (INIS)

    Pedersen, Bent; Mayorov, Valeriy; Roesgen, Eric; Mosconi, Marita; Crochemore, Jean-Michel; Ocherashvili, Aharon; Beck, Arie; Ettedgui, Hanania

    2014-01-01

    A method for the detection of special nuclear materials (SNM) in shielded containers which is both sensitive and easily applicable under field conditions is presented. The method applies neutron induced fission in SNM by means of an external pulsed neutron source with subsequent detection of the fast prompt fission neutrons. Liquid scintillation detectors surrounding the container under investigation are able to discriminate gamma rays from fast neutrons by the so-called pulse shape discrimination technique (PSD)

  2. The effect of pulsed electric fields on carotenoids bioaccessibility

    NARCIS (Netherlands)

    Bot, Francesca; Verkerk, Ruud; Mastwijk, Hennie; Anese, Monica; Fogliano, Vincenzo; Capuano, Edoardo

    2018-01-01

    Tomato fractions were subjected to pulsed electric fields treatment combined or not with heating. Results showed that pulsed electric fields and heating applied in combination or individually induced permeabilization of cell membranes in the tomato fractions. However, no changes in β-carotene and

  3. Rotation Detection Using the Precession of Molecular Electric Dipole Moment

    Science.gov (United States)

    Ke, Yi; Deng, Xiao-Bing; Hu, Zhong-Kun

    2017-11-01

    We present a method to detect the rotation by using the precession of molecular electric dipole moment in a static electric field. The molecular electric dipole moments are polarized under the static electric field and a nonzero electric polarization vector emerges in the molecular gas. A resonant radio-frequency pulse electric field is applied to realize a 90° flip of the electric polarization vector of a particular rotational state. After the pulse electric field, the electric polarization vector precesses under the static electric field. The rotation induces a shift in the precession frequency which is measured to deduce the angular velocity of the rotation. The fundamental sensitivity limit of this method is estimated. This work is only a proposal and does not involve experimental results.

  4. Electric field measurements in a nanosecond pulse discharge in atmospheric air

    International Nuclear Information System (INIS)

    Simeni Simeni, Marien; Frederickson, Kraig; Lempert, Walter R; Adamovich, Igor V; Goldberg, Benjamin M; Zhang, Cheng

    2017-01-01

    The paper presents the results of temporally and spatially resolved electric field measurements in a nanosecond pulse discharge in atmospheric air, sustained between a razor edge high-voltage electrode and a plane grounded electrode covered by a thin dielectric plate. The electric field is measured by picosecond four-wave mixing in a collinear phase-matching geometry, with time resolution of approximately 2 ns, using an absolute calibration provided by measurements of a known electrostatic electric field. The results demonstrate electric field offset on the discharge center plane before the discharge pulse due to surface charge accumulation on the dielectric from the weaker, opposite polarity pre-pulse. During the discharge pulse, the electric field follows the applied voltage until ‘forward’ breakdown occurs, after which the field in the plasma is significantly reduced due to charge separation. When the applied voltage is reduced, the field in the plasma reverses direction and increases again, until the weak ‘reverse’ breakdown occurs, producing a secondary transient reduction in the electric field. After the pulse, the field is gradually reduced on a microsecond time scale, likely due to residual surface charge neutralization by transport of opposite polarity charges from the plasma. Spatially resolved electric field measurements show that the discharge develops as a surface ionization wave. Significant surface charge accumulation on the dielectric surface is detected near the end of the discharge pulse. Spatially resolved measurements of electric field vector components demonstrate that the vertical electric field in the surface ionization wave peaks ahead of the horizontal electric field. Behind the wave, the vertical field remains low, near the detection limit, while the horizontal field is gradually reduced to near the detection limit at the discharge center plane. These results are consistent with time-resolved measurements of electric field

  5. Electrical pulse burnout of transistors in intense ionizing radiation

    International Nuclear Information System (INIS)

    Hartman, E.F.; Evans, D.C.

    1975-01-01

    Tests examining possible synergistic effects of electrical pulses and ionizing radiation on transistors were performed and energy/power thresholds for transistor burnout determined. The effect of ionizing radiation on burnout thresholds was found to be minimal, indicating that electrical pulse testing in the absence of radiation produces burnout-threshold results which are applicable to IEMP studies. The conditions of ionized transistor junctions and radiation induced current surges at semiconductor device terminals are inherent in IEMP studies of electrical circuits

  6. [Mechanism of ablation with nanosecond pulsed electric field].

    Science.gov (United States)

    Cen, Chao; Chen, Xin-hua; Zheng, Shu-sen

    2015-11-01

    Nanosecond pulsed electric field ablation has been widely applied in clinical cancer treatment, while its molecular mechanism is still unclear. Researchers have revealed that nanosecond pulsed electric field generates nanopores in plasma membrane, leading to a rapid influx of Ca²⁺; it has specific effect on intracellular organelle membranes, resulting in endoplasmic reticulum injuries and mitochondrial membrane potential changes. In addition, it may also change cellular morphology through damage of cytoskeleton. This article reviews the recent research advances on the molecular mechanism of cell membrane and organelle changes induced by nanosecond pulsed electric field ablation.

  7. Pulsed electric fields for pasteurization: defining processing conditions

    Science.gov (United States)

    Application of pulsed electric fields (PEF) technology in food pasteurization has been extensively studied. Optimal PEF treatment conditions for maximum microbial inactivation depend on multiple factors including PEF processing conditions, production parameters and product properties. In order for...

  8. Effect of rising time of rectangular pulse on inactivation of staphylococcus aureus by pulsed electric field

    Science.gov (United States)

    Zhang, Ruobing; Liang, Dapeng; Zheng, Nanchen; Xiao, Jianfu; Mo, Mengbin; Li, Jing

    2013-03-01

    Pulsed electric field (PEF) is a novel non-thermal food processing technology that involves the electric discharge of high voltage short pulses through the food product. In PEF study, rectangular pulses are most commonly used for inactivating microorganisms. However, little information is available on the inactivation effect of rising time of rectangular pulse. In this paper, inactivation effects, electric field strength, treatment time and conductivity on staphylococcus aureus inactivation were investigated when the pulse rising time is reduced from 2.5 μs to 200 ns. Experimental results showed that inactivation effect of PEF increased with electric field strength, solution conductivity and treatment time. Rising time of the rectangular pulse had a significant effect on the inactivation of staphylococcus aureus. Rectangular pulses with a rising time of 200 ns had a better inactivation effect than that with 2 μs. In addition, temperature increase of the solution treated by pulses with 200 ns rising time was lower than that with 2 μs. In order to obtain a given inactivation effect, treatment time required for the rectangular pulse with 200 ns rise time was shorter than that with 2 μs.

  9. Effect of rising time of rectangular pulse on inactivation of staphylococcus aureus by pulsed electric field

    International Nuclear Information System (INIS)

    Zhang, Ruobing; Liang, Dapeng; Xiao, Jianfu; Mo, Mengbin; Li, Jing; Zheng, Nanchen

    2013-01-01

    Pulsed electric field (PEF) is a novel non-thermal food processing technology that involves the electric discharge of high voltage short pulses through the food product. In PEF study, rectangular pulses are most commonly used for inactivating microorganisms. However, little information is available on the inactivation effect of rising time of rectangular pulse. In this paper, inactivation effects, electric field strength, treatment time and conductivity on staphylococcus aureus inactivation were investigated when the pulse rising time is reduced from 2.5 μs to 200 ns. Experimental results showed that inactivation effect of PEF increased with electric field strength, solution conductivity and treatment time. Rising time of the rectangular pulse had a significant effect on the inactivation of staphylococcus aureus. Rectangular pulses with a rising time of 200 ns had a better inactivation effect than that with 2 μs. In addition, temperature increase of the solution treated by pulses with 200 ns rising time was lower than that with 2 μs. In order to obtain a given inactivation effect, treatment time required for the rectangular pulse with 200 ns rise time was shorter than that with 2 μs.

  10. Pulsed Electric Fields for Biological Weapons Defense

    National Research Council Canada - National Science Library

    Gundersen, Martin A

    2008-01-01

    Pulsed power for biological investigations newly developed at USC include a fast diode-based systems designed to drive cell suspensions in a microscope slide electrode microchamber for observations...

  11. Electrical response of relaxing dielectrics compressed by arbitrary stress pulses

    International Nuclear Information System (INIS)

    Lysne, P.C.

    1983-01-01

    The theoretical problem of the electric response of biased dielectrics and piezoelectrics subjected to planar stress pulse loading is considered. The materials are taken to exhibit dielectric relaxation in the sense that changes in the polarization induced by electric fields do not occur instantaneously with changes in the fields. While this paper considers arbitrary stress pulse loading of the specimen, examples that are amenable to projectile impact techniques are considered in detail. They are shock reverberation, thin pulse, and ramp loading experiments. It is anticipated that these experiments will play a role in investigations of dielectric relaxation caused by shock induced damage in insulators

  12. Pulsed electrical discharges for medicine and biology techniques, processes, applications

    CERN Document Server

    Kolikov, Victor

    2015-01-01

    This book presents the application of pulsed electrical discharges in water and water dispersions of metal nanoparticles in medicine (surgery, dentistry, and oncology), biology, and ecology. The intensive electrical and shock waves represent a novel technique to destroy viruses and this way to  prepare anti-virus vaccines. The method of pulsed electrical discharges in water allows to decontaminate water from almost all known bacteria and spores of fungi being present in human beings. The nanoparticles used are not genotoxic and mutagenic. This book is useful for researchers and graduate students.

  13. Design of electron detection system for pulse electron irradiator

    International Nuclear Information System (INIS)

    Anjar Anggraini H; Agus Purwadi; Lely Susita RM; Bambang Siswanto; Agus Wijayanto

    2016-01-01

    Design of electron detection system for pulse electron irradiator has been conducted on the Plasma Cathode Electron Source by Rogowski coil technique. Rogowski coil has ability to capture the induced magnetic field of the electric current, subsequent induced magnetic field will provide voltage after passing integrator. This diagnostic used combination of copper wire, ferrite and RC integrator. The design depends on the pulse width and the value of plasma current that passes through the coil, thus the number of windings, coil area and integrator can be designed. For plasma spots current of IDPS expected to be 10 A and pulse width 10 μs the Rogowski coil using MnZn ferrite with inductance L = 0.275 mH and permeability μr = 200 H/m. For the current of plasma arc ADPS expected to be 100 A and pulse width 100 μs by using inductance L=1.9634 mH and permeability μr = 6256 H/m. Electron current in extraction system expected to be 30 A and pulse width 100 μs the Rogowski coil using inductance L=51.749 mH and permeability μr= 4987 H/m. Design integrator used is the type of RC integrator. (author)

  14. Preliminary Optical And Electric Field Pulse Statistics From Storm Overflights During The Altus Cumulus Electrification Study

    Science.gov (United States)

    Mach, D. A.; Blakeslee, R. J.; Bailey, J. C.; Farrell, W. M.; Goldberg, R. A.; Desch, M. D.; Houser, J. G.

    2003-01-01

    The Altus Cumulus Electrification Study (ACES) was conducted during the month of August, 2002 in an area near Key West, Florida. One of the goals of this uninhabited aerial vehicle (UAV) study was to collect high resolution optical pulse and electric field data from thunderstorms. During the month long campaign, we acquired 5294 lightning generated optical pulses with associated electric field changes. Most of these observations were made while close to the top of the storms. We found filtered mean and median 10-10% optical pulse widths of 875 and 830 microns respectively while the 50-50% mean and median optical pulse widths are 422 and 365 microns respectively. These values are similar to previous results as are the 10-90% mean and median rise times of 327 and 265 microns. The peak electrical to optical pulse delay mean and median were 209 and 145 microns which is longer than one would expect from theoretical results. The results of the pulse analysis will contribute to further validation of the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS) satellites. Pre-launch estimates of the flash detection efficiency were based on a small sample of optical pulse measurements associated with less than 350 lightning discharges collected by NASA U-2 aircraft in the early 1980s. Preliminary analyses of the ACES measurements show that we have greatly increased the number of optical pulses available for validation of the LIS and other orbital lightning optical sensors. Since the Altus was often close to the cloud tops, many of the optical pulses are from low-energy pulses. From these low-energy pulses, we can determine the fraction of optical lightning pulses below the thresholds of LIS, OTD, and any future satellite-based optical sensors such as the geostationary Lightning Mapping Sensor.

  15. Microsecond-scale electric field pulses in cloud lightning discharges

    Science.gov (United States)

    Villanueva, Y.; Rakov, V. A.; Uman, M. A.; Brook, M.

    1994-01-01

    From wideband electric field records acquired using a 12-bit digitizing system with a 500-ns sampling interval, microsecond-scale pulses in different stages of cloud flashes in Florida and New Mexico are analyzed. Pulse occurrence statistics and waveshape characteristics are presented. The larger pulses tend to occur early in the flash, confirming the results of Bils et al. (1988) and in contrast with the three-stage representation of cloud-discharge electric fields suggested by Kitagawa and Brook (1960). Possible explanations for the discrepancy are discussed. The tendency for the larger pulses to occur early in the cloud flash suggests that they are related to the initial in-cloud channel formation processes and contradicts the common view found in the atmospheric radio-noise literature that the main sources of VLF/LF electromagnetic radiation in cloud flashes are the K processes which occur in the final, or J type, part of the cloud discharge.

  16. Electric field measurements in nanosecond pulse discharges in air over liquid water surface

    Science.gov (United States)

    Simeni Simeni, Marien; Baratte, Edmond; Zhang, Cheng; Frederickson, Kraig; Adamovich, Igor V.

    2018-01-01

    Electric field in nanosecond pulse discharges in ambient air is measured by picosecond four-wave mixing, with absolute calibration by a known electrostatic field. The measurements are done in two geometries, (a) the discharge between two parallel cylinder electrodes placed inside quartz tubes, and (b) the discharge between a razor edge electrode and distilled water surface. In the first case, breakdown field exceeds DC breakdown threshold by approximately a factor of four, 140 ± 10 kV cm-1. In the second case, electric field is measured for both positive and negative pulse polarities, with pulse durations of ˜10 ns and ˜100 ns, respectively. In the short duration, positive polarity pulse, breakdown occurs at 85 kV cm-1, after which the electric field decreases over several ns due to charge separation in the plasma, with no field reversal detected when the applied voltage is reduced. In a long duration, negative polarity pulse, breakdown occurs at a lower electric field, 30 kV cm-1, after which the field decays over several tens of ns and reverses direction when the applied voltage is reduced at the end of the pulse. For both pulse polarities, electric field after the pulse decays on a microsecond time scale, due to residual surface charge neutralization by transport of opposite polarity charges from the plasma. Measurements 1 mm away from the discharge center plane, ˜100 μm from the water surface, show that during the voltage rise, horizontal field component (Ex ) lags in time behind the vertical component (Ey ). After breakdown, Ey is reduced to near zero and reverses direction. Further away from the water surface (≈0.9 mm), Ex is much higher compared to Ey during the entire voltage pulse. The results provide insight into air plasma kinetics and charge transport processes near plasma-liquid interface, over a wide range of time scales.

  17. Pulsed electric field sensor based on original waveform measurement

    International Nuclear Information System (INIS)

    Ma Liang; Wu Wei; Cheng Yinhui; Zhou Hui; Li Baozhong; Li Jinxi; Zhu Meng

    2010-01-01

    The paper introduces the differential and original waveform measurement principles for pulsed E-field, and develops an pulsed E-field sensor based on original waveform measurement along with its theoretical correction model. The sensor consists of antenna, integrator, amplifier and driver, optic-electric/electric-optic conversion module and transmission module. The time-domain calibration in TEM cell indicates that, its risetime response is shorter than 1.0 ns, and the output pulse width at 90% of the maximum amplitude is wider than 10.0 μs. The output amplitude of the sensor is linear to the electric field intensity in a dynamic range of 20 dB. The measurement capability can be extended to 10 V/m or 50 kV/m by changing the system's antenna and other relative modules. (authors)

  18. Skin Rejuvenation with Non-Invasive Pulsed Electric Fields

    Science.gov (United States)

    Golberg, Alexander; Khan, Saiqa; Belov, Vasily; Quinn, Kyle P.; Albadawi, Hassan; Felix Broelsch, G.; Watkins, Michael T.; Georgakoudi, Irene; Papisov, Mikhail; Mihm, Martin C., Jr.; Austen, William G., Jr.; Yarmush, Martin L.

    2015-05-01

    Degenerative skin diseases affect one third of individuals over the age of sixty. Current therapies use various physical and chemical methods to rejuvenate skin; but since the therapies affect many tissue components including cells and extracellular matrix, they may also induce significant side effects, such as scarring. Here we report on a new, non-invasive, non-thermal technique to rejuvenate skin with pulsed electric fields. The fields destroy cells while simultaneously completely preserving the extracellular matrix architecture and releasing multiple growth factors locally that induce new cells and tissue growth. We have identified the specific pulsed electric field parameters in rats that lead to prominent proliferation of the epidermis, formation of microvasculature, and secretion of new collagen at treated areas without scarring. Our results suggest that pulsed electric fields can improve skin function and thus can potentially serve as a novel non-invasive skin therapy for multiple degenerative skin diseases.

  19. Skin Rejuvenation with Non-Invasive Pulsed Electric Fields

    Science.gov (United States)

    Golberg, Alexander; Khan, Saiqa; Belov, Vasily; Quinn, Kyle P.; Albadawi, Hassan; Felix Broelsch, G.; Watkins, Michael T.; Georgakoudi, Irene; Papisov, Mikhail; Mihm Jr., Martin C.; Austen Jr., William G.; Yarmush, Martin L.

    2015-01-01

    Degenerative skin diseases affect one third of individuals over the age of sixty. Current therapies use various physical and chemical methods to rejuvenate skin; but since the therapies affect many tissue components including cells and extracellular matrix, they may also induce significant side effects, such as scarring. Here we report on a new, non-invasive, non-thermal technique to rejuvenate skin with pulsed electric fields. The fields destroy cells while simultaneously completely preserving the extracellular matrix architecture and releasing multiple growth factors locally that induce new cells and tissue growth. We have identified the specific pulsed electric field parameters in rats that lead to prominent proliferation of the epidermis, formation of microvasculature, and secretion of new collagen at treated areas without scarring. Our results suggest that pulsed electric fields can improve skin function and thus can potentially serve as a novel non-invasive skin therapy for multiple degenerative skin diseases. PMID:25965851

  20. Effects of pulsed electric field on ULQ and RFP plasmas

    International Nuclear Information System (INIS)

    Watanabe, M.; Saito, K.; Suzuki, T.

    1997-01-01

    Dynamo activity and self-organization processes are investigated using the application of pulsed poloidal and toroidal electric fields on ULQ and RFP plasmas. Synchronized to the application of the pulsed electric fields, the remarkable responses of the several plasma parameters are observed. The plasma has a preferential magnetic field structure, and the external perturbation activates fluctuation to maintain the structure through dynamo effect. This process changes the total dissipation with the variation of magnetic helicity in the system, showing that self organization accompanies an enhanced dissipation. (author)

  1. [Rapid measurement of trace mercury in aqueous solutions with optical-electrical dual pulse LIBS technique].

    Science.gov (United States)

    Zhang, Qian; Xiong, Wei; Chen, Yu-Qi; Li, Run-Hua

    2011-02-01

    A wood slice was used as absorber to transfer liquid sample to solid sample in order to solve the problems existing in directly analyzing aqueous solutions with laser-induced breakdown spectroscopy (LIBS). An optical-electrical dual pulse LIBS (OEDP-LIBS) technique was first used to enhance atomic emission of mercury in laser-induced plasma. The calibration curves of mercury were obtained by typical single pulse LIBS and OEDP-LIBS techniques. The limit of detection (LOD) of mercury in these two techniques reaches 2.4 and 0.3 mg x L(-1), respectively. Under current experimental conditions, the time-integrated a tomic emission of mercury at 253.65 nm was enhanced 50 times and the LOD of mercury was improved by one order, if comparing OEDP-LIBS to single pulse LIBS. The required time for a whole analysis process is less than 5 minutes. As the atomic emission of mercury decays slowly while increasing the delay time between electrical pulse and laser pulse, increasing the electrical pulse width can further enhance the time integrated intensity of mercury emission and improve the detection sensitivity of mercury by OEDP-LIBS technique.

  2. Pulse-driven magnetoimpedance sensor detection of cardiac magnetic activity.

    Directory of Open Access Journals (Sweden)

    Shinsuke Nakayama

    Full Text Available This study sought to establish a convenient method for detecting biomagnetic activity in the heart. Electrical activity of the heart simultaneously induces a magnetic field. Detection of this magnetic activity will enable non-contact, noninvasive evaluation to be made. We improved the sensitivity of a pulse-driven magnetoimpedance (PMI sensor, which is used as an electric compass in mobile phones and as a motion sensor of the operation handle in computer games, toward a pico-Tesla (pT level, and measured magnetic fields on the surface of the thoracic wall in humans. The changes in magnetic field detected by this sensor synchronized with the electric activity of the electrocardiogram (ECG. The shape of the magnetic wave was largely altered by shifting the sensor position within 20 mm in parallel and/or perpendicular to the thoracic wall. The magnetic activity was maximal in the 4th intercostals near the center of the sterna. Furthermore, averaging the magnetic activity at 15 mm in the distance between the thoracic wall and the sensor demonstrated magnetic waves mimicking the P wave and QRS complex. The present study shows the application of PMI sensor in detecting cardiac magnetic activity in several healthy subjects, and suggests future applications of this technology in medicine and biology.

  3. Generation of short electrical pulses based on bipolar transistorsny

    Directory of Open Access Journals (Sweden)

    M. Gerding

    2004-01-01

    Full Text Available A system for the generation of short electrical pulses based on the minority carrier charge storage and the step recovery effect of bipolar transistors is presented. Electrical pulses of about 90 ps up to 800 ps duration are generated with a maximum amplitude of approximately 7V at 50Ω. The bipolar transistor is driven into saturation and the base-collector and base-emitter junctions become forward biased. The resulting fast switch-off edge of the transistor’s output signal is the basis for the pulse generation. The fast switching of the transistor occurs as a result of the minority carriers that have been injected and stored across the base-collector junction under forward bias conditions. If the saturated transistor is suddenly reverse biased the pn-junction will appear as a low impedance until the stored charge is depleted. Then the impedance will suddenly increase to its normal high value and the flow of current through the junction will turn to zero, abruptly. A differentiation of the output signal of the transistor results in two short pulses with opposite polarities. The differentiating circuit is implemented by a transmission line network, which mainly acts as a high pass filter. Both the transistor technology (pnp or npn and the phase of the transfer function of the differentating circuit influence the polarity of the output pulses. The pulse duration depends on the transistor parameters as well as on the transfer function of the pulse shaping network. This way of generating short electrical pulses is a new alternative for conventional comb generators based on steprecovery diodes (SRD. Due to the three-terminal structure of the transistor the isolation problem between the input and the output signal of the transistor network is drastically simplified. Furthermore the transistor is an active element in contrast to a SRD, so that its current gain can be used to minimize the power of the driving signal.

  4. Nanosecond pulsed electric field ablation of hepatocellular carcinoma.

    Science.gov (United States)

    Beebe, Stephen J; Chen, Xinhua; Liu, Jie A; Schoenbach, Karl H

    2011-01-01

    Hepatocellular carcinoma often evades effective therapy and recurrences are frequent. Recently, nanosecond pulsed electric field (nsPEF) ablation using pulse power technology has emerged as a local-regional, non-thermal, and non-drug therapy for skin cancers. In the studies reported here we use nsPEFs to ablate murine, rat and human HCCs in vitro and an ectopic murine Hepa 1-6 HCC in vivo. Using pulses with 60 or 300 ns and electric fields as high as 60 kV/cm, murine Hepa 1-6, rat N1S1 and human HepG2 HCC are readily eliminated with changes in caspase-3 activity. Interestingly caspase activities increase in the mouse and human model and decrease in the rat model as electric field strengths are increased. In vivo, while sham treated control mice survived an average of 15 days after injection and before humane euthanasia, Hepa 1-6 tumors were eliminated for longer than 50 days with 3 treatments using one hundred pulses with 100 ns at 55 kV/cm. Survival was 40% in mice treated with 30 ns pulses at 55 kV/cm. This study demonstrates that nsPEF ablation is not limited to effectively treating skin cancers and provides a rationale for treating orthotopic hepatocellular carcinoma in pre-clinical applications and ultimately in clinical trials.

  5. Formation of the electrical pulse in the SQS mode

    International Nuclear Information System (INIS)

    Han Jiaxiang; Xu Zizong; Li Hongdi; Chen Hongfang

    1994-01-01

    The pulse of the electrical signals from the counter working in SQS mode have been displayed and studied carefully. Some interesting information on the formation of SQS avalanche has been presented. The typical value of the transition time from the primary to the SQS avalanche is 15 ns, that of its spread is 10 ns

  6. Pulsed electric field processing for fruit and vegetables

    Science.gov (United States)

    This month’s column reviews the theory and current applications of pulsed electric field (PEF) processing for fruits and vegetables to improve their safety and quality. This month’s column coauthor, Stefan Toepfl, is advanced research manager at the German Institute of Food Technologies and professo...

  7. Pulsed electric field (PEF)research at USDA, ARS, ERRC

    Science.gov (United States)

    This article summarizes the effects of pulsed electric fields on the microbiological safety and quality aspects of various liquid food matrices, obtained at USDA, ARS, Eastern Regional Research Center under CRIS Project No. 1935-41420-013-00D, Processing Intervention Technologies for Enhancing the S...

  8. Production of pulsed electric fields using capacitively coupled electrodes

    Science.gov (United States)

    Kendall, B. R. F.; Schwab, F. A. S.

    1980-01-01

    It is shown that pulsed electric fields can be produced over extended volumes by taking advantage of the internal capacitances in a stacked array of electrodes. The design, construction, and performance of practical arrays are discussed. The prototype arrays involved fields of 100-1000 V/cm extending over several centimeters. Scaling to larger physical dimensions is straightforward.

  9. Design of Electric Field Sensors for Measurement of Electromagnetic Pulse

    Directory of Open Access Journals (Sweden)

    Hui ZHANG

    2014-01-01

    Full Text Available In this paper, a D-dot electric field sensor and a fiber-optic transmission electric field sensor are developed for measurement of electromagnetic pulse. The D-dot sensor is a differential model sensor without source and has a simple structure. The fiber-optic transmission sensor is in the type of small dipole antenna, which uses its outside shielding layer as a pair of antennas. Design of the sensor circuit and the test system are introduced in this paper. A calibration system for these pulsed field sensors is established and the test results verified the ability of the developed sensors for measurement of the standard electromagnetic pulse field (the half peak width is 25 ns and the rising time is 2.5 ns.

  10. Pulsed electric fields (PEF applications on wine production: A review

    Directory of Open Access Journals (Sweden)

    Ozturk Burcu

    2017-01-01

    Full Text Available Novel techniques have been searched in the last decades as a result of increasing demand for high quality food products. Non-thermal processing technologies, such as pulsed electric fields (PEF have been improved to achieve inhibition of deleterious effects on quality-related compounds. The working principle of PEF is based on the application of pulses of high voltage (typically above 20 kV/cm up to 70 kV/cm to liquid foods placed between two electrodes. Pulsed electric fields technique has also been studied in winemaking process. Certain positive influences of PEF on vinification have been reported as elimination of pathogenic microorganisms, reduction of maceration time, increase in phenolic compounds extraction , acceleration of wine aging and inactivation of oxidative enzymes. The aim of this review is to summarize the potential applications of PEF in winemaking and to express its effects on quality of wine.

  11. Interactions of pulsed electric fields with living organisms

    International Nuclear Information System (INIS)

    Vezinet, R.; Joly, J.C.; Meyer, O.; Gilbert, C.; Fourrier-Lamer, A.; Silve, A.; Mir, L.M.; Rols, M.P.; Chopinet, L.; Teissie, J.; Roux, D.

    2013-01-01

    Biologists are more and more involved in the study of the interactions of electromagnetic fields with human body for therapeutics and health applications. In this article we present 4 studies. The first study concerns the interaction between the electromagnetic field and the biochemical reaction of the hydrolysis of the acetylcholine, a primary neurotransmitter of the human body. It has been shown that a progressive slowing-down of the reaction appears when the pulse repetition frequency increases. The second study is dedicated to the effects of electromagnetic pulses at the cell membrane level. We know that electromagnetic pulses can alter the permeability of the cell membrane. We have used rectangular electromagnetic pulses to allow chemicals to enter the cell. In the case of cancer treatment the efficiency of a chemicals like bleomycin can be largely increased. The third study is dedicated to the use of 2 electromagnetic pulses of different duration to optimize gene transfer into the cell nucleus. The last study focuses on the analysis of plant reactions when facing electromagnetic pulses. An experiment performed on a sunflower shows that despite high electric fields no electro-physiological response of the plant has been measured when the sunflower was submitted to electromagnetic pulses

  12. Ionization and recombination in attosecond electric field pulses

    International Nuclear Information System (INIS)

    Dimitrovski, Darko; Solov'ev, Eugene A.; Briggs, John S.

    2005-01-01

    Based on the results of a previous communication [Dimitrovski et al., Phys. Rev. Lett. 93, 083003 (2004)], we study ionization and excitation of a hydrogenic atom from the ground and first excited states in short electric field pulses of several cycles. A process of ionization and recombination which occurs periodically in time is identified, for both small and extremely large peak electric field strengths. In the limit of large electric peak fields closed-form analytic expressions for the population of the initial state after single- and few-cycle pulses are derived. These formulas, strictly valid for asymptotically large momentum transfer from the field, give excellent agreement with fully numerical calculations for all momentum transfers

  13. Nanoparticle mechanics: deformation detection via nanopore resistive pulse sensing

    Science.gov (United States)

    Darvish, Armin; Goyal, Gaurav; Aneja, Rachna; Sundaram, Ramalingam V. K.; Lee, Kidan; Ahn, Chi Won; Kim, Ki-Bum; Vlahovska, Petia M.; Kim, Min Jun

    2016-07-01

    Solid-state nanopores have been widely used in the past for single-particle analysis of nanoparticles, liposomes, exosomes and viruses. The shape of soft particles, particularly liposomes with a bilayer membrane, can greatly differ inside the nanopore compared to bulk solution as the electric field inside the nanopores can cause liposome electrodeformation. Such deformations can compromise size measurement and characterization of particles, but are often neglected in nanopore resistive pulse sensing. In this paper, we investigated the deformation of various liposomes inside nanopores. We observed a significant difference in resistive pulse characteristics between soft liposomes and rigid polystyrene nanoparticles especially at higher applied voltages. We used theoretical simulations to demonstrate that the difference can be explained by shape deformation of liposomes as they translocate through the nanopores. Comparing our results with the findings from electrodeformation experiments, we demonstrated that the rigidity of liposomes can be qualitatively compared using resistive pulse characteristics. This application of nanopores can provide new opportunities to study the mechanics at the nanoscale, to investigate properties of great value in fundamental biophysics and cellular mechanobiology, such as virus deformability and fusogenicity, and in applied sciences for designing novel drug/gene delivery systems.Solid-state nanopores have been widely used in the past for single-particle analysis of nanoparticles, liposomes, exosomes and viruses. The shape of soft particles, particularly liposomes with a bilayer membrane, can greatly differ inside the nanopore compared to bulk solution as the electric field inside the nanopores can cause liposome electrodeformation. Such deformations can compromise size measurement and characterization of particles, but are often neglected in nanopore resistive pulse sensing. In this paper, we investigated the deformation of various

  14. Fresh water disinfection by pulsed low electric field

    International Nuclear Information System (INIS)

    Zheng, C; Xu, Y; Liu, Z; Yan, K

    2013-01-01

    In this paper, we describe a pulsed low electric field process for water disinfection. Electric intensity of 0.6–1.7 kV cm −1 is applied. Experiments are performed with a 1.2 L axis-cylinder reactor. A bipolar pulsed power source with pulsed width of 25 μs and frequency of 100–3000 Hz is used. Water conductivity of 3–200 μs cm −1 is investigated, which can significantly affect pulsed voltage-current waveforms and injected energy. Energy per pulse rises with increased water conductivity. The initial E. Coli density and water conductivity are two major factors influencing the disinfection. No disinfection effect is performed with deionized water of 3 μs cm −1 . When water conductivity is 25 μs cm −1 and bacteria density is 10 4 –10 6 cfu ml −1 , significant disinfection effect is observed. More than 99% of the cells can be disinfected with an energy density of less than 70 J ml −1 , while water temperature is below 30 °C.

  15. Nanosecond electric pulses modulate skeletal muscle calcium dynamics and contraction

    Science.gov (United States)

    Valdez, Chris; Jirjis, Michael B.; Roth, Caleb C.; Barnes, Ronald A.; Ibey, Bennett L.

    2017-02-01

    Irreversible electroporation therapy is utilized to remove cancerous tissues thru the delivery of rapid (250Hz) and high voltage (V) (1,500V/cm) electric pulses across microsecond durations. Clinical research demonstrated that bipolar (BP) high voltage microsecond pulses opposed to monophasic waveforms relieve muscle contraction during electroporation treatment. Our group along with others discovered that nanosecond electric pulses (nsEP) can activate second messenger cascades, induce cytoskeletal rearrangement, and depending on the nsEP duration and frequency, initiate apoptotic pathways. Of high interest across in vivo and in vitro applications, is how nsEP affects muscle physiology, and if nuances exist in comparison to longer duration electroporation applications. To this end, we exposed mature skeletal muscle cells to monopolar (MP) and BP nsEP stimulation across a wide range of electric field amplitudes (1-20 kV/cm). From live confocal microscopy, we simultaneously monitored intracellular calcium dynamics along with nsEP-induced muscle movement on a single cell level. In addition, we also evaluated membrane permeability with Yo-PRO-1 and Propidium Iodide (PI) across various nsEP parameters. The results from our findings suggest that skeletal muscle calcium dynamics, and nsEP-induced contraction exhibit exclusive responses to both MP and BP nsEP exposure. Overall the results suggest in vivo nsEP application may elicit unique physiology and field applications compared to longer pulse duration electroporation.

  16. Crystallization of Fe83B17 amorphous alloy by electric pulses produced by a capacitor discharge

    International Nuclear Information System (INIS)

    Georgarakis, Konstantinos; Dudina, Dina V.; Mali, Vyacheslav I.; Anisimov, Alexander G.; Bulina, Natalia V.; Moreira Jorge, Alberto Jr.; Yavari, Alain R.

    2015-01-01

    Heating of conductive materials by electric current is used in many technological processes. Application of electric pulses to metallic glasses induces their fast crystallization, which is an interesting and complex phenomenon. In this work, crystallization of the Fe 83 B 17 amorphous alloy induced by pulses of electric current produced has been studied using X-ray diffraction and transmission electron microscopy. Ribbons of the alloy were directly subjected to single pulses of electric current 250 μs long formed by a capacitor discharge. As the value of ∫I 2 dt was increased from 0.33 to 2.00 A 2 s, different crystallization stages could be observed. The crystallization began through the formation of the nuclei of α-Fe. At high values of ∫I 2 dt, α-Fe and tetragonal and orthorhombic Fe 3 B and Fe 23 B 6 were detected in the crystallized ribbons with crystallites of about 50 nm. Thermal annealing of the ribbons at 600 C for 2 min resulted in the formation of α-Fe and tetragonal Fe 3 B. It was concluded that pulses of electric current produced by a capacitor discharge induced transformation of the Fe 83 B 17 amorphous phase into metastable crystalline products. (orig.)

  17. Electrical detection of hyperfine interactions in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hoehne, Felix

    2012-12-15

    The main focus of this work was the measurement of hyperfine interactions of defects in silicon using EDMR. We combined the high sensitivity of EDMR when compared to conventional ESR with the two most commonly used methods for the measurement of hyperfine interactions: ESEEM and ENDOR. We first demonstrated the electrical detection of ESEEM by measuring the hyperfine interactions of {sup 31}P donors in Si:P with {sup 29}Si nuclear spins. We then apply EDESEEM to P{sub b0} defects at the Si/SiO{sub 2} interface. In isotopically engineered, we observe an ESEEM modulation with a characteristic beating caused by {sup 29}Si nuclei at 4th and 5th nearest neighbor lattice sites. Then we combine pulsed ENDOR with the high sensitivity of EDMR (EDENDOR). First we demonstrate the measurement of {sup 31}P nuclear spin hyperfine transitions and the coherent manipulation and readout of the {sup 31}P nuclear spins under continuous illumination with above bandgap light. We further show that the EDENDOR method can be greatly improved by switching off the illumination during the microwave and rf pulses. This improves the signal-to-noise ratio by two orders of magnitude and removes the non-resonant background induced by the strong rf pulse allowing to measure ENDOR with a sensitivity <3000 nuclear spins. We apply EDENDOR to the {sup 31}P-P{sub b0} spin system and the {sup 31}P-SL1 spin system allowing us to compare the hyperfine interactions of bulk and interface-near donors. The pulsed illumination also makes spectroscopy of the {sup 31}P{sup +} nuclear spin possible, which due to its long coherence time of 18 ms compared to 280 {mu}s for the {sup 31}P{sub 0} nuclear spin, might be a candidate for a nuclear spin memory. In the last part, we devise a scheme for the hyperpolarization of {sup 31}P nuclei by combining pulsed optical excitation and pulsed ENDOR and demonstrate a {sup 31}P nuclear spin polarization of more than 50%. Crucial for these experiments was the development of a

  18. Electrical detection of hyperfine interactions in silicon

    International Nuclear Information System (INIS)

    Hoehne, Felix

    2012-01-01

    The main focus of this work was the measurement of hyperfine interactions of defects in silicon using EDMR. We combined the high sensitivity of EDMR when compared to conventional ESR with the two most commonly used methods for the measurement of hyperfine interactions: ESEEM and ENDOR. We first demonstrated the electrical detection of ESEEM by measuring the hyperfine interactions of 31 P donors in Si:P with 29 Si nuclear spins. We then apply EDESEEM to P b0 defects at the Si/SiO 2 interface. In isotopically engineered, we observe an ESEEM modulation with a characteristic beating caused by 29 Si nuclei at 4th and 5th nearest neighbor lattice sites. Then we combine pulsed ENDOR with the high sensitivity of EDMR (EDENDOR). First we demonstrate the measurement of 31 P nuclear spin hyperfine transitions and the coherent manipulation and readout of the 31 P nuclear spins under continuous illumination with above bandgap light. We further show that the EDENDOR method can be greatly improved by switching off the illumination during the microwave and rf pulses. This improves the signal-to-noise ratio by two orders of magnitude and removes the non-resonant background induced by the strong rf pulse allowing to measure ENDOR with a sensitivity 31 P-P b0 spin system and the 31 P-SL1 spin system allowing us to compare the hyperfine interactions of bulk and interface-near donors. The pulsed illumination also makes spectroscopy of the 31 P + nuclear spin possible, which due to its long coherence time of 18 ms compared to 280 μs for the 31 P 0 nuclear spin, might be a candidate for a nuclear spin memory. In the last part, we devise a scheme for the hyperpolarization of 31 P nuclei by combining pulsed optical excitation and pulsed ENDOR and demonstrate a 31 P nuclear spin polarization of more than 50%. Crucial for these experiments was the development of a lock-in detection scheme for pEDMR, which improves the signal-to-noise ratio by one order of magnitude by removing low

  19. Underwater electric field detection system based on weakly electric fish

    Science.gov (United States)

    Xue, Wei; Wang, Tianyu; Wang, Qi

    2018-04-01

    Weakly electric fish sense their surroundings in complete darkness by their active electric field detection system. However, due to the insufficient detection capacity of the electric field, the detection distance is not enough, and the detection accuracy is not high. In this paper, a method of underwater detection based on rotating current field theory is proposed to improve the performance of underwater electric field detection system. First of all, we built underwater detection system based on the theory of the spin current field mathematical model with the help of the results of previous researchers. Then we completed the principle prototype and finished the metal objects in the water environment detection experiments, laid the foundation for the further experiments.

  20. Effects of pulsed electrical field processing on microbial survival, quality change and nutritional characteristics of blueberries

    Science.gov (United States)

    Whole fresh blueberries were treated using a parallel pulsed electric field (PEF) treatment chamber and a sanitizer solution (60 ppm peracetic acid [PAA]) as PEF treatment medium with square wave bipolar pulses at 2 kV/cm electric field strength, 1us pulse width, and 100 pulses per second for 2, 4, ...

  1. Electrosensitization Increases Antitumor Effectiveness of Nanosecond Pulsed Electric Fields In Vivo

    OpenAIRE

    Muratori, Claudia; Pakhomov, Andrei G.; Heller, Loree; Casciola, Maura; Gianulis, Elena; Grigoryev, Sergey; Xiao, Shu; Pakhomova, O. N.

    2017-01-01

    Nanosecond pulsed electric fields are emerging as a new modality for tissue and tumor ablation. We previously reported that cells exposed to pulsed electric fields develop hypersensitivity to subsequent pulsed electric field applications. This phenomenon, named electrosensitization, is evoked by splitting the pulsed electric field treatment in fractions (split-dose treatments) and causes in vitro a 2- to 3-fold increase in cytotoxicity. The aim of this study was to show the benefit of split-d...

  2. Active RF Pulse Compression Using An Electrically Controlled Semiconductor Switch

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jiquan; Tantawi, Sami; /SLAC

    2007-01-10

    First we review the theory of active pulse compression systems using resonant delay lines. Then we describe the design of an electrically controlled semiconductor active switch. The switch comprises an active window and an overmoded waveguide three-port network. The active window is based on a four-inch silicon wafer which has 960 PIN diodes. These are spatially combined in an overmoded waveguide. We describe the philosophy and design methodology for the three-port network and the active window. We then present the results of using this device to compress 11.4 GHz RF signals with high compression ratios. We show how the system can be used with amplifier like sources, in which one can change the phase of the source by manipulating the input to the source. We also show how the active switch can be used to compress a pulse from an oscillator like sources, which is not possible with passive pulse compression systems.

  3. The role of nanosecond electric pulse-induced mechanical stress in cellular nanoporation

    Science.gov (United States)

    Roth, Caleb C.

    , fluorescent confocal microscopy, microarray analysis and or real time polymerase chain reaction. To investigate the physical interaction(s) of the electrical pulse with the aqueous environment, optical techniques such as pump-probe imaging, schlieren imaging, and probe beam deflection were used. Finally, electrochemistry was employed to modify the electrical parameters of the exposures such that different biophysical phenomena could be detected. Results: Approximately 500 genes were selectively up-regulated in each of the assayed cells. Validation of the microarray data indicated genes such as the putative transforming gene of avian sarcoma virus 17, commonly known as jun proto-oncogene, and the Finkel--Biskis--Jinkins murine osteosarcoma viral oncogene homolog were significantly up-regulated in response to the exposure. Many of the genes selectively up-regulated in each cell type are biomarkers of mechanical stress. Proteomic analysis indicated proteins responsible for mitigation of reactive oxygen species were produced in response to nanosecond electrical pulse exposure. Analysis using the Probe Beam Deflection Technique identified the generation of an acoustic pressure transient emanating from the electrodes immediately after the application of the pulse. This acoustic pressure transient traveled at approximately 1500 meters per second, had a frequency bandwidth of 2.5 megahertz and was capable of delivering 13 kilopascals of pressure at 5 millimeters distance from the generating electrodes. Visual confirmation of the acoustic pressure transients was accomplished using pump-probe, schlieren and ultrasonic imaging techniques. Modification of the bathing media in which the cells were exposed indicated that acoustic pressure transient formation was directly dependent on the amount of electrical current induced by the exposure. Confocal microscopy revealed that, in the absence of the acoustic pressure transients, nanoporation, as detected by a green fluorescent carbocyanine

  4. Pulsed high voltage electric discharge disinfection of microbially contaminated liquids.

    Science.gov (United States)

    Anpilov, A M; Barkhudarov, E M; Christofi, N; Kop'ev, V A; Kossyi, I A; Taktakishvili, M I; Zadiraka, Y

    2002-01-01

    To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

  5. Nanosecond electric pulses trigger actin responses in plant cells

    International Nuclear Information System (INIS)

    Berghoefer, Thomas; Eing, Christian; Flickinger, Bianca; Hohenberger, Petra; Wegner, Lars H.; Frey, Wolfgang; Nick, Peter

    2009-01-01

    We have analyzed the cellular effects of nanosecond pulsed electrical fields on plant cells using fluorescently tagged marker lines in the tobacco cell line BY-2 and confocal laser scanning microscopy. We observe a disintegration of the cytoskeleton in the cell cortex, followed by contraction of actin filaments towards the nucleus, and disintegration of the nuclear envelope. These responses are accompanied by irreversible permeabilization of the plasma membrane manifest as uptake of Trypan Blue. By pretreatment with the actin-stabilizing drug phalloidin, the detachment of transvacuolar actin from the cell periphery can be suppressed, and this treatment can also suppress the irreversible perforation of the plasma membrane. We discuss these findings in terms of a model, where nanosecond pulsed electric fields trigger actin responses that are key events in the plant-specific form of programmed cell death.

  6. Briquetting of titanium shavings with using of short electrical pulses

    International Nuclear Information System (INIS)

    Abramova, K.B.; Samujlov, S.D.; Filin, Yu.A.

    1998-01-01

    It is proposed and tested a new technology of briquetting of metallic shavings. The technology includes pressing of shavings with comparatively low pressure and processing it by means of short pulse of high density electrical current. Strength of the briquette arrears as a result of the sport electric welding of the contacts between the shaving particles. The technology permits: to produce firm briquettes from the shavings or other scrap of any metal or alloy, for example from titanium; to produce briquettes practically of any porosity; to decrease the compression and abandon heating almost for high-strength alloy in comparison with existing methods [ru

  7. Electrical control of calcium oscillations in mesenchymal stem cells using microsecond pulsed electric fields.

    Science.gov (United States)

    Hanna, Hanna; Andre, Franck M; Mir, Lluis M

    2017-04-20

    Human mesenchymal stem cells are promising tools for regenerative medicine due to their ability to differentiate into many cellular types such as osteocytes, chondrocytes and adipocytes amongst many other cell types. These cells present spontaneous calcium oscillations implicating calcium channels and pumps of the plasma membrane and the endoplasmic reticulum. These oscillations regulate many basic functions in the cell such as proliferation and differentiation. Therefore, the possibility to mimic or regulate these oscillations might be useful to regulate mesenchymal stem cells biological functions. One or several electric pulses of 100 μs were used to induce Ca 2+ spikes caused by the penetration of Ca 2+ from the extracellular medium, through the transiently electropermeabilized plasma membrane, in human adipose mesenchymal stem cells from several donors. Attached cells were preloaded with Fluo-4 AM and exposed to the electric pulse(s) under the fluorescence microscope. Viability was also checked. According to the pulse(s) electric field amplitude, it is possible to generate a supplementary calcium spike with properties close to those of calcium spontaneous oscillations, or, on the contrary, to inhibit the spontaneous calcium oscillations for a very long time compared to the pulse duration. Through that inhibition of the oscillations, Ca 2+ oscillations of desired amplitude and frequency could then be imposed on the cells using subsequent electric pulses. None of the pulses used here, even those with the highest amplitude, caused a loss of cell viability. An easy way to control Ca 2+ oscillations in mesenchymal stem cells, through their cancellation or the addition of supplementary Ca 2+ spikes, is reported here. Indeed, the direct link between the microsecond electric pulse(s) delivery and the occurrence/cancellation of cytosolic Ca 2+ spikes allowed us to mimic and regulate the Ca 2+ oscillations in these cells. Since microsecond electric pulse delivery

  8. Energy-Saving Sintering of Electrically Conductive Powders by Modified Pulsed Electric Current Heating Using an Electrically Nonconductive Die

    Science.gov (United States)

    Ito, Mikio; Kawahara, Kenta; Araki, Keita

    2014-04-01

    Sintering of Cu and thermoelectric Ca3Co4O9 was tried using a modified pulsed electric current sintering (PECS) process, where an electrically nonconductive die was used instead of a conventional graphite die. The pulsed electric current flowed through graphite punches and sample powder, which caused the Joule heating of the powder compact itself, resulting in sintering under smaller power consumption. Especially for the Ca3Co4O9 powder, densification during sintering was also accelerated by this modified PECS process.

  9. Pulsed electrical discharge in gas bubbles in water

    Science.gov (United States)

    Gershman, Sophia

    A phenomenological picture of pulsed electrical discharge in gas bubbles in water is produced by combining electrical, spectroscopic, and imaging methods. The discharge is generated by applying one microsecond long 5 to 20 kilovolt pulses between the needle and disk electrodes submerged in water. A gas bubble is generated at the tip of the needle electrode. The study includes detailed experimental investigation of the discharge in argon bubbles and a brief look at the discharge in oxygen bubbles. Imaging, electrical characteristics, and time-resolved optical emission data point to a fast streamer propagation mechanism and formation of a plasma channel in the bubble. Spectroscopic methods based on line intensity ratios and Boltzmann plots of line intensities of argon, atomic hydrogen, and argon ions and the examination of molecular emission bands from molecular nitrogen and hydroxyl radicals provide evidence of both fast beam-like electrons and slow thermalized ones with temperatures of 0.6 -- 0.8 electron-volts. The collisional nature of plasma at atmospheric pressure affects the decay rates of optical emission. Spectroscopic study of rotational-vibrational bands of hydroxyl radical and molecular nitrogen gives vibrational and rotational excitation temperatures of the discharge of about 0.9 and 0.1 electron-volt, respectively. Imaging and electrical evidence show that discharge charge is deposited on the bubble wall and water serves as a dielectric barrier for the field strength and time scales of this experiment. Comparing the electrical and imaging information for consecutive pulses applied at a frequency of 1 Hz indicates that each discharge proceeds as an entirely new process with no memory of the previous discharge aside from long-lived chemical species, such as ozone and oxygen. Intermediate values for the discharge gap and pulse duration, low repetition rate, and unidirectional character of the applied voltage pulses make the discharge process here unique

  10. Electrical pulse burnout testing of light-emitting diodes

    International Nuclear Information System (INIS)

    Kalma, A.H.; Fischer, C.J.

    1975-01-01

    Electrical pulse burnout thresholds were measured in GaAs, GaAsP, and GaP light-emitting diodes (LEDs) by studying the degradation in light output and the change in I-V characteristics both during the pulse and in the steady state. Pulse widths ranging from a few hundred nsec to 100 μsec were used. Light output degradation was the most sensitive parameter and was used to determine the thresholds. Just above threshold, damage is caused by an increase in generation-recombination current in the space-charge retion. This current is non-radiative and the light output drops, but the damage is not catastrophic. At higher power, the junction burns through and shunt resistance paths are formed which more drastically degrade the light output. The experimental data match reasonably with the theoretical Wunsch--Bell/Tasca model if a burnout area of 1 / 10 the junction area is assumed. Both the adiabatic term (At -1 ) and the heat flow term (Bt - /sup 1 / 2 /) contribute in all devices, and the equilibrium term (C) contributes in some GaAsP devices. The scatter in the data for GaAs devices is greater than that for GaAsP devices, apparently because the former types have a significant fraction of mavericks with lower-than-normal thresholds. The use of LEDs to examine electrical pulse burnout is advantageous because the light output is quite sensitive to damage and the combined measurement of optical and electrical properties provides additional information about the mechanisms involved

  11. The effect of pulsed electric fields on carotenoids bioaccessibility: The role of tomato matrix.

    Science.gov (United States)

    Bot, Francesca; Verkerk, Ruud; Mastwijk, Hennie; Anese, Monica; Fogliano, Vincenzo; Capuano, Edoardo

    2018-02-01

    Tomato fractions were subjected to pulsed electric fields treatment combined or not with heating. Results showed that pulsed electric fields and heating applied in combination or individually induced permeabilization of cell membranes in the tomato fractions. However, no changes in β-carotene and lycopene bioaccessibility were found upon combined and individual pulsed electric fields and heating, except in the following cases: (i) in tissue, a significant decrease in lycopene bioaccessibility upon combined pulsed electric fields and heating and heating only was observed; (ii) in chromoplasts, both β-carotene and lycopene bioaccessibility significantly decreased upon combined pulsed electric fields and heating and pulsed electric fields only. The reduction in carotenoids bioaccessibility was attributed to modification in chromoplasts membrane and carotenoids-protein complexes. Differences in the effects of pulsed electric fields on bioaccessibility among different tomato fractions were related to tomato structure complexity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Applications of lightweight composite materials in pulsed rotating electrical generators

    International Nuclear Information System (INIS)

    Walls, W.A.; Maifold, S.M.

    1987-01-01

    Present rotating electrical pulse power generators are limited in energy storage capability, specific energy, and peak power density by the use of iron-magnetic circuits. This paper discusses lightweight and compact iron-core homopolar generators (HPGs) which have attained specific energies of 6 kJ/kg and have the potential to achieve 8 kJ/kg in the near future. Prototype iron based pulsed alternators are the favored choice for high power to mass ratio applications and have estimated peak ratings of 180 kW/kg. In terms of total energy storage capability, these machines are limited to several hundred MJ due to the availability of large steel forgings for rotors and basic design considerations including rotor dynamics, allowable rotor tip speeds, and present high speed current collection technology

  13. Chemical Detection using Electrically Open Circuits having no Electrical Connections

    Science.gov (United States)

    Woodward, Stanley E.; Olgesby, Donald M.; Taylor, Bryant D.; Shams, Qamar A.

    2008-01-01

    This paper presents investigations to date on chemical detection using a recently developed method for designing, powering and interrogating sensors as electrically open circuits having no electrical connections. In lieu of having each sensor from a closed circuit with multiple electrically connected components, an electrically conductive geometric pattern that is powered using oscillating magnetic fields and capable of storing an electric field and a magnetic field without the need of a closed circuit or electrical connections is used. When electrically active, the patterns respond with their own magnetic field whose frequency, amplitude and bandwidth can be correlated with the magnitude of the physical quantities being measured. Preliminary experimental results of using two different detection approaches will be presented. In one method, a thin film of a reactant is deposited on the surface of the open-circuit sensor. Exposure to a specific targeted reactant shifts the resonant frequency of the sensor. In the second method, a coating of conductive material is placed on a thin non-conductive plastic sheet that is placed over the surface of the sensor. There is no physical contact between the sensor and the electrically conductive material. When the conductive material is exposed to a targeted reactant, a chemical reaction occurs that renders the material non-conductive. The change in the material s electrical resistance within the magnetic field of the sensor alters the sensor s response bandwidth and amplitude, allowing detection of the reaction without having the reactants in physical contact with the sensor.

  14. Fermentation Assisted by Pulsed Electric Field and Ultrasound: A Review

    Directory of Open Access Journals (Sweden)

    Leandro Galván-D’Alessandro

    2018-01-01

    Full Text Available Various novel techniques are proposed to improve process efficiency, quality, and safety of fermented food products. Ultrasound and pulsed electric field (PEF are versatile technologies that can be employed in conjunction with fermentation processes to enhance process efficiency and production rates by improving mass transfer and cell permeability. The aim of this review is to highlight current and potential applications of ultrasound and PEF techniques in food fermentation processes. Their effects on microbial enzymes, along with mechanisms of action, are also discussed.

  15. Shock waves in water at low energy pulsed electric discharges

    International Nuclear Information System (INIS)

    Pinchuk, M E; Kolikov, V A; Rutberg, Ph G; Leks, A G; Dolinovskaya, R V; Snetov, V N; Stogov, A Yu

    2012-01-01

    Experimental results of shock wave formation and propagation in water at low energy pulsed electric discharges are presented. To study the hydrodynamic structure of the shock waves, the direct shadow optical diagnostic device with time resolution of 5 ns and spatial resolution of 0.1 mm was designed and developed. Synchronization of the diagnostic and electrodischarge units by the fast optocouplers was carried out. The dependences of shock wave velocities after breakdown of interelectrode gap for various energy inputs (at range of ≤1 J) into discharge were obtained. Based on the experimental results the recommendations for the adjustment parameters of the power supply and load were suggested.

  16. Impact of external medium conductivity on cell membrane electropermeabilization by microsecond and nanosecond electric pulses

    Science.gov (United States)

    Silve, Aude; Leray, Isabelle; Poignard, Clair; Mir, Lluis M.

    2016-01-01

    The impact of external medium conductivity on the efficiency of the reversible permeabilisation caused by pulsed electric fields was investigated. Pulses of 12 ns, 102 ns or 100 μs were investigated. Whenever permeabilisation could be detected after the delivery of one single pulse, media of lower conductivity induced more efficient reversible permeabilisation and thus independently of the medium composition. Effect of medium conductivity can however be hidden by some saturation effects, for example when pulses are cumulated (use of trains of 8 pulses) or when the detection method is not sensitive enough. This explains the contradicting results that can be found in the literature. The new data are complementary to those of one of our previous study in which an opposite effect of the conductivity was highlighted. It stresses that the conductivity of the medium influences the reversible permeabilization by several ways. Moreover, these results clearly indicate that electropermeabilisation does not linearly depend on the energy delivered to the cells. PMID:26829153

  17. Inactivation of Listeria monocytogenes in milk by pulsed electric field.

    Science.gov (United States)

    Reina, L D; Jin, Z T; Zhang, Q H; Yousef, A E

    1998-09-01

    Pasteurized whole, 2%, and skim milk were inoculated with Listeria monocytogenes Scott A and treated with high-voltage pulsed electric field (PEF). The effects of milk composition (fat content) and PEF parameters (electric field strength, treatment time, and treatment temperature) on the inactivation of the bacterium were studied. No significant differences were observed in the inactivation of L. monocytogenes Scott A in three types of milk by PEF treatment. With treatment at 25 degrees C, 1- to 3-log reductions of L. monocytogenes were observed. PEF lethal effect was a function of field strength and treatment time. Higher field strength or longer treatment time resulted in a greater reduction of viable cells. A 4-log reduction of the bacterium was obtained by increasing the treatment temperature to 50 degrees C. Results indicate that the use of a high-voltage PEF is a promising technology for inactivation of foodborne pathogens.

  18. Sludge pre-treatment with pulsed electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Kopplow, O.; Barjenbruch, M.; Heinz, V.

    2003-07-01

    The anaerobic stabilization process depends - among others - on the bio-availability of organic carbon. Through pre-treatment of the sludge which leads to the destruction of micro-organisms and to the setting-free of cell content substances (disintegration), the carbon can be microbially converted better and faster. Moreover, effects on the digestion are likely. However, only little experience is available in the sludge treatment with pulsed electric fields. Laboratory-scale digestion tests have been run to analyse the influence of pulsed electric fields on the properties of sludge, anaerobic degradation, sludge water reload and foaming of digesters. The results will be compared with those of other disintegration methods (high pressure homogenise, thermal treatment). The effect of pre-treatment on the sludge is shown by the COD release. Degrees of disintegration have been achieved up to 20%. The specific energy input was high. The energy consumption has been decreased by initial improvements (pre-heating to 55{sup o}C). The filament bacteria were partially destroyed. The foam reduction in the digesters was marginal. The anaerobic degradation performance has been improved in every case. The degradation rate of organic matter increased about 9%. Due to the increase of degradation, there is a higher reload of the sludge-water with COD and nitrogen compounds. (author)

  19. A new pulsed electric field microreactor: comparison between the laboratory and microtechnology scale

    NARCIS (Netherlands)

    Fox, M.B.; Fox, Martijn; Esveld, Erik; Lüttge, Regina; Boom, Remko

    This paper presents a new microreactor dedicated for pulsed electric field treatment (PEF), which is a pasteurization method that inactivates microorganisms with short electric pulses. The PEF microreactor consists of a flow-through channel with a constriction where the electric field is focussed.

  20. A new pulsed electric field microreactor: comparison between the laboratory and microtechnology scale

    NARCIS (Netherlands)

    Fox, M.B.; Esveld, D.C.; Luttge, R.; Boom, R.M.

    2005-01-01

    This paper presents a new microreactor dedicated for pulsed electric field treatment (PEF), which is a pasteurization method that inactivates microorganisms with short electric pulses. The PEF microreactor consists of a flow-through channel with a constriction where the electric field is focussed.

  1. Combination of microsecond and nanosecond pulsed electric field treatments for inactivation of Escherichia coli in water samples.

    Science.gov (United States)

    Žgalin, Maj Kobe; Hodžić, Duša; Reberšek, Matej; Kandušer, Maša

    2012-10-01

    Inactivation of microorganisms with pulsed electric fields is one of the nonthermal methods most commonly used in biotechnological applications such as liquid food pasteurization and water treatment. In this study, the effects of microsecond and nanosecond pulses on inactivation of Escherichia coli in distilled water were investigated. Bacterial colonies were counted on agar plates, and the count was expressed as colony-forming units per milliliter of bacterial suspension. Inactivation of bacterial cells was shown as the reduction of colony-forming units per milliliter of treated samples compared to untreated control. According to our results, when using microsecond pulses the level of inactivation increases with application of more intense electric field strengths and with number of pulses delivered. Almost 2-log reductions in bacterial counts were achieved at a field strength of 30 kV/cm with eight pulses and a 4.5-log reduction was observed at the same field strength using 48 pulses. Extending the duration of microsecond pulses from 100 to 250 μs showed no improvement in inactivation. Nanosecond pulses alone did not have any detectable effect on inactivation of E. coli regardless of the treatment time, but a significant 3-log reduction was achieved in combination with microsecond pulses.

  2. Pulsed homodyne Gaussian quantum tomography with low detection efficiency

    Science.gov (United States)

    Esposito, M.; Benatti, F.; Floreanini, R.; Olivares, S.; Randi, F.; Titimbo, K.; Pividori, M.; Novelli, F.; Cilento, F.; Parmigiani, F.; Fausti, D.

    2014-04-01

    Pulsed homodyne quantum tomography usually requires a high detection efficiency, limiting its applicability in quantum optics. Here, it is shown that the presence of low detection efficiency (<50%) does not prevent the tomographic reconstruction of quantum states of light, specifically, of Gaussian states. This result is obtained by applying the so-called ‘minimax’ adaptive reconstruction of the Wigner function to pulsed homodyne detection. In particular, we prove, by both numerical and real experiments, that an effective discrimination of different Gaussian quantum states can be achieved. Our finding paves the way to a more extensive use of quantum tomographic methods, even in physical situations in which high detection efficiency is unattainable.

  3. Pulsed homodyne Gaussian quantum tomography with low detection efficiency

    International Nuclear Information System (INIS)

    Esposito, M; Benatti, F; Randi, F; Titimbo, K; Pividori, M; Parmigiani, F; Fausti, D; Floreanini, R; Olivares, S; Novelli, F; Cilento, F

    2014-01-01

    Pulsed homodyne quantum tomography usually requires a high detection efficiency, limiting its applicability in quantum optics. Here, it is shown that the presence of low detection efficiency (<50) does not prevent the tomographic reconstruction of quantum states of light, specifically, of Gaussian states. This result is obtained by applying the so-called ‘minimax’ adaptive reconstruction of the Wigner function to pulsed homodyne detection. In particular, we prove, by both numerical and real experiments, that an effective discrimination of different Gaussian quantum states can be achieved. Our finding paves the way to a more extensive use of quantum tomographic methods, even in physical situations in which high detection efficiency is unattainable

  4. Review of the Dynamics of Coalescence and Demulsification by High-Voltage Pulsed Electric Fields

    Directory of Open Access Journals (Sweden)

    Ye Peng

    2016-01-01

    Full Text Available The coalescence of droplets in oil can be implemented rapidly by high-voltage pulse electric field, which is an effective demulsification dehydration technological method. At present, it is widely believed that the main reason of pulse electric field promoting droplets coalescence is the dipole coalescence and oscillation coalescence in pulse electric field, and the optimal coalescence pulse electric field parameters exist. Around the above content, the dynamics of high-voltage pulse electric field promoting the coalescence of emulsified droplets is studied by researchers domestically and abroad. By review, the progress of high-voltage pulse electric field demulsification technology can get a better understanding, which has an effect of throwing a sprat to catch a whale on promoting the industrial application.

  5. The effect of applied electric field on pulsed radio frequency and pulsed direct current plasma jet array

    International Nuclear Information System (INIS)

    Hu, J. T.; Liu, X. Y.; Liu, J. H.; Xiong, Z. L.; Liu, D. W.; Lu, X. P.; Iza, F.; Kong, M. G.

    2012-01-01

    Here we compare the plasma plume propagation characteristics of a 3-channel pulsed RF plasma jet array and those of the same device operated by a pulsed dc source. For the pulsed-RF jet array, numerous long life time ions and metastables accumulated in the plasma channel make the plasma plume respond quickly to applied electric field. Its structure similar as “plasma bullet” is an anode glow indeed. For the pulsed dc plasma jet array, the strong electric field in the vicinity of the tube is the reason for the growing plasma bullet in the launching period. The repulsive forces between the growing plasma bullets result in the divergence of the pulsed dc plasma jet array. Finally, the comparison of 309 nm and 777 nm emissions between these two jet arrays suggests the high chemical activity of pulsed RF plasma jet array.

  6. Development of Long-Lifetime Pulsed Gas Valves for Pulsed Electric Thrusters

    Science.gov (United States)

    Burkhardt, Wendel M.; Crapuchettes, John M.; Addona, Brad M.; Polzin, Kurt A.

    2015-01-01

    It is advantageous for gas-fed pulsed electric thrusters to employ pulsed valves so propellant is only flowing to the device during operation. The propellant utilization of the thruster will be maximized when all the gas injected into the thruster is acted upon by the fields produced by the electrical pulse. Gas that is injected too early will diffuse away from the thruster before the electrical pulse can act to accelerate the propellant. Gas that is injected too late will miss being accelerated by the already-completed electrical pulse. As a consequence, the valve must open quickly and close equally quickly, only remaining open for a short duration. In addition, the valve must have only a small amount of volume between the sealing body and the thruster so the front and back ends of the pulse are as coincident as possible with the valve cycling, with very little latent propellant remaining in the feed lines after the valve is closed. For a real mission of interest, a pulsed thruster can be expected to pulse at least 10(exp 10) - 10(exp 11) times, setting the range for the number of times a valve must open and close. The valves described in this paper have been fabricated and tested for operation in an inductive pulsed plasma thruster (IPPT) for in-space propulsion. In general, an IPPT is an electrodeless space propulsion device where a capacitor is charged to an initial voltage and then discharged, producing a high-current pulse through a coil. The field produced by this pulse ionizes propellant, inductively driving current in a plasma located near the face of the coil. Once the plasma is formed, it can be accelerated and expelled at a high exhaust velocity by the electromagnetic Lorentz body force arising from the interaction of the induced plasma current and the magnetic field produced by the current in the coil. The valve characteristics needed for the IPPT application require a fast-acting valve capable of a minimum of 10(exp 10) valve actuation cycles. Since

  7. High-intensity pulsed electric field variables affecting Staphylococcus aureus inoculated in milk.

    Science.gov (United States)

    Sobrino-López, A; Raybaudi-Massilia, R; Martín-Belloso, O

    2006-10-01

    Staphylococcus aureus is an important milk-related pathogen that is inactivated by high-intensity pulsed electric fields (HIPEF). In this study, inactivation of Staph. aureus suspended in milk by HIPEF was studied using a response surface methodology, in which electric field intensity, pulse number, pulse width, pulse polarity, and the fat content of milk were the controlled variables. It was found that the fat content of milk did not significantly affect the microbial inactivation of Staph. aureus. A maximum value of 4.5 log reductions was obtained by applying 150 bipolar pulses of 8 mus each at 35 kV/cm. Bipolar pulses were more effective than those applied in the monopolar mode. An increase in electric field intensity, pulse number, or pulse width resulted in a drop in the survival fraction of Staph. aureus. Pulse widths close to 6.7 micros lead to greater microbial death with a minimum number of applied pulses. At a constant treatment time, a greater number of shorter pulses achieved better inactivation than those treatments performed at a lower number of longer pulses. The combined action of pulse number and electric field intensity followed a similar pattern, indicating that the same fraction of microbial death can be reached with different combinations of the variables. The behavior and relationship among the electrical variables suggest that the energy input of HIPEF processing might be optimized without decreasing the microbial death.

  8. Detection of movement artifact in recorded pulse oximeter saturation.

    Science.gov (United States)

    Poets, C F; Stebbens, V A

    1997-10-01

    Movement artifact (MA) must be detected when analysing recordings of pulse oximeter saturation (SpO2). Visual analysis of individual pulse waveforms is the safest, but also the most tedious, method for this purpose. We wanted to test the reliability of a computer algorithm (Edentec Motion Annotation System), based on a comparison between pulse and heart rate, for MA detection. Ten 12-h recordings of SpO2, pulse waveforms and heart rate from ten preterm infants were analysed for the presence of MA on the pulse waveform signal. These data were used to determine the sensitivity and specificity of the computer algorithm, and of the oximeter itself, in detecting MA. Recordings were divided into segments of 2.5 s duration to compare the movement identification methods. Of the segments 31% +/- 6% (mean +/- SD) contained MA. The computer algorithm identified 95% +/- 3% of these segments, the pulse oximeter only 18% +/- 11%. Specificity was 85% +/- 4% and 99% +/- 0%, respectively. SpO2 was signal showed MA during this time, leaving a significant potential for erroneous identification of hypoxaemia. Recordings of SpO2 do not allow a reliable identification of MA. Without additional information about movement artifact, a significant proportion of recording time of pulse oximeter signal may be regarded as demonstrating hypoxaemia which, in fact, simply reflects poor measurement conditions. The computer algorithm used in this study identified periods of movement artifact reliably.

  9. Electric pulse treatment of welded joint of aluminum alloy

    Directory of Open Access Journals (Sweden)

    A.A. Mitiaev

    2013-08-01

    Full Text Available Purpose. Explanation of the redistribution effect of residual strengthes after electric pulse treatment of ark welding seam of the aluminum alloy. Methodology. Alloy on the basis of aluminium of АК8М3 type served as the research material. As a result of mechanical treatment of the ingots after alloy crystallization the plates with 10 mm thickness were obtained. After edge preparation the elements, which are being connected were butt welded using the technology of semiautomatic argon arc welding by the electrode with a diameter of 3 mm of AK-5 alloy. Metal structure of the welded joint was examined under the light microscope at a magnification of 200 and under the scanning electronic microscope «JSM-6360 LA». The Rockwell hardness (HRF was used as a strength characteristic of alloy. Hardness measuring of the phase constituents (microhardness was carried out using the device PМТ-3, with the indenter loadings 5 and 10 g. The crystalline structure parameters of alloy (dislocation density, second kind of the crystalline grid distortion and the scale of coherent scattering regions were determined using the methods of X-ray structural analysis. Electric pulse treatment (ET was carried out on the special equipment in the conditions of the DS enterprise using two modes A and В. Findings. On the basis of researches the previously obtained microhardness redistribution effect in the area of welded connection after ET was confirmed. As a result of use of the indicated treatment it was determined not only the reduction of microhardness gradient but also the simultaneous hardening effect in the certain thermal affected areas near the welding seam. During study of chemical composition of phase constituents it was discovered, that the structural changes of alloy as a result of ET first of all are caused by the redistribution of chemical elements, which form the connections themselves. By the nature of the influence the indicated treatment can be

  10. Numerical simulation of nanosecond-pulse electrical discharges

    Science.gov (United States)

    Poggie, J.; Adamovich, I.; Bisek, N.; Nishihara, M.

    2013-02-01

    Recent experiments with a nanosecond-pulse, dielectric barrier discharge at the stagnation point of a Mach 5 cylinder flow have demonstrated the formation of weak shock waves near the electrode edge, which propagate upstream and perturb the bow shock. This is a promising means of flow control, and understanding the detailed physics of the conversion of electrical energy into gas motion will aid in the design of efficient actuators based on the concept. In this work, a simplified configuration with planar symmetry was chosen as a vehicle to develop a physics-based model of nanosecond-pulse discharges, including realistic air kinetics, electron energy transport, and compressible bulk gas flow. A reduced plasma kinetic model (23 species and 50 processes) was developed to capture the dominant species and reactions for energy storage and thermalization in the discharge. The kinetic model included electronically and vibrationally excited species, and several species of ions and ground state neutrals. The governing equations included the Poisson equation for the electric potential, diffusion equations for each neutral species, conservation equations for each charged species, and mass-averaged conservation equations for the bulk gas flow. The results of calculations with this model highlighted the path of energy transfer in the discharge. At breakdown, the input electrical energy was transformed over a time scale on the order of 1 ns into chemical energy of ions, dissociation products, and vibrationally and electronically excited particles. About 30% of this energy was subsequently thermalized over a time scale of 10 µs. Since the thermalization time scale was faster than the acoustic time scale, the heat release led to the formation of weak shock waves originating near the sheath edge, consistent with experimental observations. The computed translational temperature rise (40 K) and nitrogen vibrational temperature rise (370 K) were of the same order of magnitude as

  11. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Catrin F., E-mail: williamscf@cardiff.ac.uk [School of Engineering, Cardiff University, Queen' s Buildings, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom); School of Biosciences, Cardiff University, Main Building, Cathays Park, Cardiff, CF10 3AT Wales (United Kingdom); Geroni, Gilles M.; Pirog, Antoine; Lees, Jonathan; Porch, Adrian [School of Engineering, Cardiff University, Queen' s Buildings, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom); Lloyd, David [School of Biosciences, Cardiff University, Main Building, Cathays Park, Cardiff, CF10 3AT Wales (United Kingdom)

    2016-08-29

    Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the “internet of things” is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

  12. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

    Science.gov (United States)

    Williams, Catrin F.; Geroni, Gilles M.; Pirog, Antoine; Lloyd, David; Lees, Jonathan; Porch, Adrian

    2016-08-01

    Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the "internet of things" is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

  13. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

    International Nuclear Information System (INIS)

    Williams, Catrin F.; Geroni, Gilles M.; Pirog, Antoine; Lees, Jonathan; Porch, Adrian; Lloyd, David

    2016-01-01

    Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the “internet of things” is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

  14. Deashing macroalgae biomass by pulsed electric field treatment.

    Science.gov (United States)

    Robin, Arthur; Sack, Martin; Israel, Alvaro; Frey, Wolfgang; Müller, Georg; Golberg, Alexander

    2018-05-01

    Among all biomass constituents, the ashes are major hurdles for biomass processing. Ashes currently have low market value and can make a non-negligible fraction of the biomass dry weight significantly impacting its further processing by degrading equipment, lowering process yield, inhibiting reactions and decreasing products qualities. However, most of the current treatments for deashing biomass are of poor efficiency or industrial relevance. This work is the first report on the use of Pulsed Electric Field (PEF) to enhance deashing of biomass from a high ash content green marine macroalga, Ulva sp., using hydraulic pressing. By inducing cell permeabilization of the fresh biomass, PEF was able to enhance the ash extraction from 18.4% (non-treated control) to 37.4% of the total ash content in average, significantly enhancing the extraction of five of the major ash elements (K, Mg, Na, P and S) compared to pressing alone. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Electrical and hydrodynamic characterization of a high current pulsed arc

    International Nuclear Information System (INIS)

    Sousa Martins, R; Chemartin, L; Zaepffel, C; Lalande, Ph; Soufiani, A

    2016-01-01

    High current pulsed arcs are of significant industrial interest and, aiming to reduce time and cost, there is progressively more and more need for computation tools that describe and predict the behaviour of these arcs. These simulation codes need inputs and validations by experimental databases, but accurate data is missing for this category of electric discharges. The principal lack of understanding is with respect to the transient phase of the current, which can reach thousands of amperes in a few microseconds. In this paper, we present the work realized on an experimental setup that simulates in the laboratory an arc column subjected to five levels of high pulsed current, ranging from 10 kA to 100 kA, with the last one corresponding to the standard lightning current waveform used in aircraft certification processes. This device was instrumented by high speed video cameras to assess the characteristic sizes of the arc channel and to characterize the shock wave generated by the arc expansion. The arc channel radius was measured over time during the axisymmetric phase and reached 3.2 cm. The position and velocity of the shock wave was determined during the first 140 μs. The background-oriented schlieren method was used to study the shock wave and a model for the light deflection inside the shock wave was developed. The mass density profile of the shock wave was estimated and showed good agreement with Rankine–Hugoniot relations at the wave front. Electrical measurements were also used to estimate the time-dependent resistance and conductivity of the arc for times lasting up to 50 μs. (paper)

  16. Electrical and hydrodynamic characterization of a high current pulsed arc

    Science.gov (United States)

    Sousa Martins, R.; Chemartin, L.; Zaepffel, C.; Lalande, Ph; Soufiani, A.

    2016-05-01

    High current pulsed arcs are of significant industrial interest and, aiming to reduce time and cost, there is progressively more and more need for computation tools that describe and predict the behaviour of these arcs. These simulation codes need inputs and validations by experimental databases, but accurate data is missing for this category of electric discharges. The principal lack of understanding is with respect to the transient phase of the current, which can reach thousands of amperes in a few microseconds. In this paper, we present the work realized on an experimental setup that simulates in the laboratory an arc column subjected to five levels of high pulsed current, ranging from 10 kA to 100 kA, with the last one corresponding to the standard lightning current waveform used in aircraft certification processes. This device was instrumented by high speed video cameras to assess the characteristic sizes of the arc channel and to characterize the shock wave generated by the arc expansion. The arc channel radius was measured over time during the axisymmetric phase and reached 3.2 cm. The position and velocity of the shock wave was determined during the first 140 μs. The background-oriented schlieren method was used to study the shock wave and a model for the light deflection inside the shock wave was developed. The mass density profile of the shock wave was estimated and showed good agreement with Rankine-Hugoniot relations at the wave front. Electrical measurements were also used to estimate the time-dependent resistance and conductivity of the arc for times lasting up to 50 μs.

  17. C-phycocyanin extraction assisted by pulsed electric field from Artrosphira platensis.

    Science.gov (United States)

    Martínez, Juan Manuel; Luengo, Elisa; Saldaña, Guillermo; Álvarez, Ignacio; Raso, Javier

    2017-09-01

    This paper assesses the application of pulsed electric fields (PEF) to the fresh biomass of Artrhospira platensis in order to enhance the extraction of C-phycocyanin into aqueous media. Electroporation of A. platensis depended on both electric field strength and treatment duration. The minimum electric field intensity for detecting C-phycocyanin in the extraction medium was 15kV/cm after the application of a treatment time 150μs (50 pulses of 3μs). However higher electric field strength were required when shorter treatment times were applied. Response surface methodology was used in order to investigate the influence of electric field strength (15-25kV/cm), treatment time (60-150μs), and temperature of application of PEF (10-40°C) on C-phycocyanin extraction yield (PEY). The increment of the temperature PEF treatment reduced the electric field strength and the treatment time required to obtain a given PEY and, consequently decreased the total specific energy delivered by the treatment. For example, the increment of temperature from 10°C to 40°C permitted to reduce the electric field strength required to extract 100mg/g d w of C-phycocyanin from 25 to 18kV/cm, and the specific energy input from 106.7 to 67.5kJ/Kg. Results obtained in this investigation demonstrated PEF's potential for selectively extraction C-phycocyanin from fresh A. platensis biomass. The purity of the C-phycocyanin extract obtained from the electroporated cells was higher than that obtained using other techniques based on the cell complete destruction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Ir-based refractory superalloys by pulse electric current sintering (PECS) process (II prealloyed powder)

    Science.gov (United States)

    Huang, C.; Yamabe-Mitarai, Y.; Harada, H.

    2002-02-01

    Five prealloyed powder samples prepared from binary Ir-based refractory superalloys were sintered at 1800 °C for 4 h by Pulse Electric Current Sintering (PECS). No metal loss was observed during sintering. The relative densities of the sintered specimens all exceeded 90% T.D. The best one was Ir-13% Hf with the density of 97.82% T.D. Phases detected in sintered samples were in accordance with the phase diagram as expected. Fractured surfaces were observed in two samples (Ir-13% Hf and Ir-15% Zr). Some improvements obtained by using prealloyed powders instead of elemental powders, which were investigated in the previous studies, were presented.

  19. Histopathology of normal skin and melanomas after nanosecond pulsed electric field treatment

    Science.gov (United States)

    Chen, Xinhua; Swanson, R. James; Kolb, Juergen F.; Nuccitelli, Richard; Schoenbach, Karl H.

    2011-01-01

    Nanosecond pulsed electric fields (nsPEFs) can affect the intracellular structures of cells in vitro. This study shows the direct effects of nsPEFs on tumor growth, tumor volume, and histological characteristics of normal skin and B16-F10 melanoma in SKH-1 mice. A melanoma model was set up by injecting B16-F10 into female SKH-1 mice. After a 100-pulse treatment with an nsPEF (40-kV/cm field strength; 300-ns duration; 30-ns rise time; 2-Hz repetition rate), tumor growth and histology were studied using transillumination, light microscopy with hematoxylin and eosin stain and transmission electron microscopy. Melanin and iron within the melanoma tumor were also detected with specific stains. After nsPEF treatment, tumor development was inhibited with decreased volumes post-nsPEF treatment compared with control tumors (Pelectric fields surrounding the needle electrodes. PMID:19730404

  20. Improving carotenoid extraction from tomato waste by pulsed electric fields.

    Directory of Open Access Journals (Sweden)

    Elisa eLuengo

    2014-08-01

    Full Text Available In this investigation, the influence of the application of Pulsed Electric Fields (PEF of different intensities (3-7 kV/cm and 0-300 μs on the carotenoid extraction from tomato peel and pulp in a mixture of hexane:acetone:ethanol was studied with the aim of increasing extraction yield or reducing the percentage of the less green solvents in the extraction medium. According to the cellular disintegration index, the optimum treatment time for the permeabilization of tomato peel and pulp at different electric field strengths was 90 µs. The PEF permeabilization of tomato pulp did not significantly increase the carotenoid extraction. However, a PEF-treatment at 5 kV/cm improved the carotenoid extraction from tomato peel by 39 % as compared with the control in a mixture of hexane:ethanol:acetone (50:25:25. Further increments of electric field from 5 to 7 kV/cm did not increase significantly the extraction of carotenoids. . The presence of acetone in the solvent mixture did not positively affect the carotenoid extraction when the tomato peels were PEF-treated. Response surface methodology was used to determine the potential of PEF for reducing the percentage of hexane in a hexane:ethanol mixture. The application of a PEF-treatment allowed reducing the hexane percentage from 45 to 30 % without affecting the carotenoid extraction yield. The antioxidant capacity of the extracts obtained from tomato peel was correlated with the carotenoid concentration and it was not affected by the PEF-treatment.

  1. Polyphenol extraction from fresh tea leaves by pulsed electric field : a study of mechanisms

    NARCIS (Netherlands)

    Zderic, Aleksandra; Zondervan, Edwin

    2016-01-01

    The major interest in pulsed electric field treatment of biological tissues is derived from its non-thermal application: increasing cell permeability. This application has an important implication in extraction of complex organic molecules. In this work, pulsed electric field treatment is

  2. Toward 6 log10 pulsed electric field inactivation with conductive plastic packaging material

    NARCIS (Netherlands)

    Roodenburg, B.; Haan, S.W.H. de; Ferreira, J.A.; Coronel, P.; Wouters, P.C.; Hatt, V.

    2013-01-01

    Generally, high grade products such as pulsed electric field (PEF) treated fruit juices are packaged after their preservative treatment. However, PEF treatment after packaging could avoid recontamination of the product and becomes feasible when electric field pulses of sufficient magnitude can be

  3. Pulsed White Spectrum Neutron Generator for Explosive Detection

    International Nuclear Information System (INIS)

    King, Michael J.; Miller, Gill T.; Reijonen, Jani; Ji, Qing; Andresen, Nord; Gicquel, Frederic; Kavlas, Taneli; Leung, Ka-Ngo; Kwan, Joe

    2008-01-01

    Successful explosive material detection in luggage and similar sized containers is a critical issue in securing the safety of all airline passengers. Tensor Technology Inc. has recently developed a methodology that will detect explosive compounds with pulsed fast neutron transmission spectroscopy. In this scheme, tritium beams will be used to generate neutrons with a broad energy spectrum as governed by the T(t,2n)4He fission reaction that produces 0-9 MeV neutrons. Lawrence Berkeley National Laboratory (LBNL), in collaboration with Tensor Technology Inc., has designed and fabricated a pulsed white-spectrum neutron source for this application. The specifications of the neutron source are demanding and stringent due to the requirements of high yield and fast pulsing neutron emission, and sealed tube, tritium operation. In a unique co-axial geometry, the ion source uses ten parallel rf induction antennas to externally couple power into a toroidal discharge chamber. There are 20 ion beam extraction slits and 3 concentric electrode rings to shape and accelerate the ion beam into a titanium cone target. Fast neutron pulses are created by using a set of parallel-plate deflectors switching between +-1500 volts and deflecting the ion beams across a narrow slit. The generator is expected to achieve 5 ns neutron pulses at tritium ion beam energies between 80-120 kV. First experiments demonstrated ion source operation and successful beam pulsing

  4. Modular Pulsed Plasma Electric Propulsion System for Cubesats

    Science.gov (United States)

    Perez, Andres Dono; Gazulla, Oriol Tintore; Teel, George Lewis; Mai, Nghia; Lukas, Joseph; Haque, Sumadra; Uribe, Eddie; Keidar, Michael; Agasid, Elwood

    2014-01-01

    Current capabilities of CubeSats must be improved in order to perform more ambitious missions. Electric propulsion systems will play a key role due to their large specific impulse. Compared to other propulsion alternatives, their simplicity allows an easier miniaturization and manufacturing of autonomous modules into the nano and pico-satellite platform. Pulsed Plasma Thrusters (PPTs) appear as one of the most promising technologies for the near term. The utilization of solid and non-volatile propellants, their low power requirements and their proven reliability in the large scale make them great candidates for rapid implementation. The main challenges are the integration and miniaturization of all the electronic circuitry into a printed circuit board (PCB) that can satisfy the strict requirements that CubeSats present. NASA Ames and the George Washington University have demonstrated functionality and control of three discrete Micro-Cathode Arc Thrusters (CAT) using a bench top configuration that was compatible with the ARC PhoneSat Bus. This demonstration was successfully conducted in a vaccum chamber at the ARC Environmental Test Laboratory. A new effort will integrate a low power Plasma Processing Unit and two plasma thrusters onto a single printed circuit board that will utilize less than 13 U of Bus volume. The target design will be optimized for the accommodation into the PhoneSatEDISON Demonstration of SmallSatellite Networks (EDSN) bus as it uses the same software interface application, which was demonstrated in the previous task. This paper describes the design, integration and architecture of the proposed propulsion subsystem for a planned Technology Demonstration Mission. In addition, a general review of the Pulsed Plasma technology available for CubeSats is presented in order to assess the necessary challenges to overcome further development.

  5. Tracing explosive in solvent using quantum cascade laser with pulsed electric discharge system

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seong-Wook; Tian, Chao; Martini, Rainer, E-mail: rmartini@stevens.edu [Department of Physics and Engineering Physics, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, New Jersey 07030 (United States); Chen, Gang [School of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China); Chen, I-chun Anderson [Newport Corporation/Oriel Instruments, 150 Long Beach Boulevard, Stratford, Connecticut 06615 (United States)

    2014-11-03

    We demonstrated highly sensitive detection of explosive dissolved in solvent with a portable spectroscopy system (Q-MACS) by tracing the explosive byproduct, N{sub 2}O, in combination with a pulsed electric discharge system for safe explosive decomposition. Using Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), the gas was monitored and analyzed by Q-MACS and the presence of the dissolved explosive clearly detected. While HMX presence could be identified directly in the air above the solutions even without plasma, much better results were achieved under the decomposition. The experiment results give an estimated detection limit of 10 ppb, which corresponds to a 15 pg of HMX.

  6. Tracing explosive in solvent using quantum cascade laser with pulsed electric discharge system

    International Nuclear Information System (INIS)

    Park, Seong-Wook; Tian, Chao; Martini, Rainer; Chen, Gang; Chen, I-chun Anderson

    2014-01-01

    We demonstrated highly sensitive detection of explosive dissolved in solvent with a portable spectroscopy system (Q-MACS) by tracing the explosive byproduct, N 2 O, in combination with a pulsed electric discharge system for safe explosive decomposition. Using Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), the gas was monitored and analyzed by Q-MACS and the presence of the dissolved explosive clearly detected. While HMX presence could be identified directly in the air above the solutions even without plasma, much better results were achieved under the decomposition. The experiment results give an estimated detection limit of 10 ppb, which corresponds to a 15 pg of HMX

  7. Test research of consistency for amplitude calibration coefficients of pulsed electric field sensor

    International Nuclear Information System (INIS)

    Meng Cui; Guo Xiaoqiang; Chen Xiangyue; Nie Xin; Mao Congguang; Xiang Hui; Cheng Jianping

    2007-01-01

    The amplitude calibration of an electric field sensor is important in the measurement of electromagnetic pulse. In this paper, an arbitrary waveform generator (AWG) is used to generate multi-waveform electric field in the TEM cell and the dipole antenna pulsed electric field sensor is calibrated. In the frequency band of the sensor, the calibrated amplitude coefficients with different waveforms are identical. The coefficient derived from the TEM cell calibration system suits to the measurement of unknown electric field pulse within the frequency band. (authors)

  8. Effect of electrical pulse on the precipitates and material strength of 2024 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Weichao, E-mail: weichao127@gmail.com; Wang, Yongjun, E-mail: t.s.wu@163.com; Wang, Junbiao, E-mail: wangjunb@nwpu.edu.cn; Wei, Shengmin, E-mail: weism@nwpu.edu.cn

    2014-07-01

    The effect of electrical pulse on the metastable precipitates and material strength of Al–Cu–Mg based 2024 aluminum alloy was investigated by means of tensile tests, hardness measurement, transmission electron microscopy and differential scanning calorimetry. The experimental results show that the electrical pulse passing through the naturally aged 2024 alloy can cause an electrical pulse retrogression effect which is characterized by the decrease of material strength and the appearance of Portevin–Le Chatelier (PLC) effect. More electrical pulses under higher current densities are more efficient in causing the electrical pulse retrogression effect. TEM and DSC experimental results reveal that, the electrical pulse retrogression effect is owing to the dissolution of the metastable precipitates in naturally aged 2024 alloy. Compared with the traditional retrogression heat treatment that heats the aluminum alloys through bulk heating in furnace for short time to reduce their material strength, the electrical pulse retrogression effect occurs at a much lower temperature and the pulse treated alloy can nearly restore to its original strength at a faster speed at room temperature.

  9. Electric field detection of coherent synchrotron radiation in a storage ring generated using laser bunch slicing

    International Nuclear Information System (INIS)

    Katayama, I.; Shimosato, H.; Bito, M.; Furusawa, K.; Adachi, M.; Zen, H.; Kimura, S.; Katoh, M.; Shimada, M.; Yamamoto, N.; Hosaka, M.; Ashida, M.

    2012-01-01

    The electric field of coherent synchrotron radiation (CSR) generated by laser bunch slicing in a storage ring has been detected by an electro-optic sampling method. The gate pulses for sampling are sent through a large-mode-area photonic-crystal fiber. The observed electric field profile of the CSR is in good agreement with the spectrum of the CSR observed using Fourier transform far-infrared spectrometry, indicating good phase stability in the CSR. The longitudinal density profiles of electrons modulated by laser pulses were evaluated from the electric field profile.

  10. Light electric transformer to transform the size of particles contained in a gas flow into electrical pulses

    Energy Technology Data Exchange (ETDEWEB)

    Berber, V.A.; Zolotenko, V.A.; Naguev, E.N.; Pavlov, V.V.; Sokolov, V.E.; Syromyatnikov, A.N.; Eremenko, A.I.

    1979-08-09

    The equipment measures the air dust. The aerosol flow is hence irradiated with a convergent light bundle. Using mirrors and mechanically operable screens, it is possible to divert part of the light onto a photo receiver to produce electric pulses of the dispersly composed aerosols and another part onto a former for standardized light pulses. The accuracy of the measurement is increased by the stability of the standardized light pulses.

  11. Hardening of alloys in glow discharge with the use of pulsed electric current

    International Nuclear Information System (INIS)

    Shipko, M.N.; Pomel'nikova, A.S.; Solunin, A.M.; Solunin, M.A.

    2002-01-01

    The effect of ex/ternal pulsed electric field on the thickness of a hardened surface layer of a Nd-Fe-B system alloy during chemical heat treatment in a glow discharge is studied. The relationship is established between the hardened layer thickness and the frequency of external electric field which is verified by derived equations for the relation between electron energy and pulsed electric field frequency [ru

  12. Ultra-wideband short-pulse radar with range accuracy for short range detection

    Energy Technology Data Exchange (ETDEWEB)

    Rodenbeck, Christopher T; Pankonin, Jeffrey; Heintzleman, Richard E; Kinzie, Nicola Jean; Popovic, Zorana P

    2014-10-07

    An ultra-wideband (UWB) radar transmitter apparatus comprises a pulse generator configured to produce from a sinusoidal input signal a pulsed output signal having a series of baseband pulses with a first pulse repetition frequency (PRF). The pulse generator includes a plurality of components that each have a nonlinear electrical reactance. A signal converter is coupled to the pulse generator and configured to convert the pulsed output signal into a pulsed radar transmit signal having a series of radar transmit pulses with a second PRF that is less than the first PRF.

  13. Comparison of membrane electroporation and protein denature in response to pulsed electric field with different durations.

    Science.gov (United States)

    Huang, Feiran; Fang, Zhihui; Mast, Jason; Chen, Wei

    2013-05-01

    In this paper, we compared the minimum potential differences in the electroporation of membrane lipid bilayers and the denaturation of membrane proteins in response to an intensive pulsed electric field with various pulse durations. Single skeletal muscle fibers were exposed to a pulsed external electric field. The field-induced changes in the membrane integrity (leakage current) and the Na channel currents were monitored to identify the minimum electric field needed to damage the membrane lipid bilayer and the membrane proteins, respectively. We found that in response to a relatively long pulsed electric shock (longer than the membrane intrinsic time constant), a lower membrane potential was needed to electroporate the cell membrane than for denaturing the membrane proteins, while for a short pulse a higher membrane potential was needed. In other words, phospholipid bilayers are more sensitive to the electric field than the membrane proteins for a long pulsed shock, while for a short pulse the proteins become more vulnerable. We can predict that for a short or ultrashort pulsed electric shock, the minimum membrane potential required to start to denature the protein functions in the cell plasma membrane is lower than that which starts to reduce the membrane integrity. Copyright © 2013 Wiley Periodicals, Inc.

  14. Measuring the electric field of few-cycle laser pulses by attosecond cross correlation

    International Nuclear Information System (INIS)

    Bandrauk, Andre D.; Chelkowski, Szczepan; Shon, Nguyen Hong

    2002-01-01

    A new technique for directly measuring the electric field of linearly polarized few-cycle laser pulses is proposed. Based on the solution of the time-dependent Schroedinger equation (TDSE) for an H atom in the combined field of infrared (IR) femtosecond (fs) and ultraviolet (UV) attosecond (as) laser pulses we show that, as a function of the time delay between two pulses, the difference (or equivalently, asymmetry) of photoelectron signals in opposite directions (along the polarization vector of laser pulses) reproduces very well the profile of the electric field (or vector potential) in the IR pulse. Such ionization asymmetry can be used for directly measuring the carrier-envelope phase difference (i.e., the relative phase of the carrier frequency with respect to the pulse envelope) of the IR fs laser pulse

  15. Energy detection UWB system based on pulse width modulation

    Directory of Open Access Journals (Sweden)

    Song Cui

    2014-05-01

    Full Text Available A new energy detection ultra-wideband system based on pulse width modulation is proposed. The bit error rate (BER performance of this new system is slightly worst than that of a pulse position modulation (PPM system in additive white Gaussian noise channels. In multipath channels, this system does not suffer from cross-modulation interference as PPM, so it can achieve better BER performance than PPM when cross-modulation interference occurs. In addition, when synchronisation errors occur, this system is more robust than PPM.

  16. Electrosensitization Increases Antitumor Effectiveness of Nanosecond Pulsed Electric Fields In Vivo.

    Science.gov (United States)

    Muratori, Claudia; Pakhomov, Andrei G; Heller, Loree; Casciola, Maura; Gianulis, Elena; Grigoryev, Sergey; Xiao, Shu; Pakhomova, O N

    2017-01-01

    Nanosecond pulsed electric fields are emerging as a new modality for tissue and tumor ablation. We previously reported that cells exposed to pulsed electric fields develop hypersensitivity to subsequent pulsed electric field applications. This phenomenon, named electrosensitization, is evoked by splitting the pulsed electric field treatment in fractions (split-dose treatments) and causes in vitro a 2- to 3-fold increase in cytotoxicity. The aim of this study was to show the benefit of split-dose treatments for in vivo tumor ablation by nanosecond pulsed electric field. KLN 205 squamous carcinoma cells were embedded in an agarose gel or grown subcutaneously as tumors in mice. Nanosecond pulsed electric field ablations were produced using a 2-needle probe with a 6.5-mm interelectrode distance. In agarose gel, splitting a pulsed electric field dose of 300, 300-ns pulses (20 Hz, 4.4-6.4 kV) in 2 equal fractions increased cell death up to 3-fold compared to single-train treatments. We then compared the antitumor effectiveness of these treatments in vivo. At 24 hours after treatment, sensitizing tumors by a split-dose pulsed electric field exposure (150 + 150, 300-ns pulses, 20 Hz, 6.4 kV) caused a 4- and 2-fold tumor volume reduction as compared to sham and single-train treatments, respectively. Tumor volume reduction that exceeds 75% was 43% for split-dose-treated animals compared to only 12% for single-dose treatments. The difference between the 2 experimental groups remained statistically significant for at least 1 week after the treatment. The results show that electrosensitization occurs in vivo and can be exploited to assist in vivo cancer ablation.

  17. Electric field simulation and measurement of a pulse line ion accelerator

    International Nuclear Information System (INIS)

    Shen Xiaokang; Zhang Zimin; Cao Shuchun; Zhao Hongwei; Zhao Quantang; Liu Ming; Jing Yi; Wang Bo; Shen Xiaoli

    2012-01-01

    An oil dielectric helical pulse line to demonstrate the principles of a Pulse Line Ion Accelerator (PLIA) has been designed and fabricated. The simulation of the axial electric field of an accelerator with CST code has been completed and the simulation results show complete agreement with the theoretical calculations. To fully understand the real value of the electric field excited from the helical line in PLIA, an optical electric integrated electric field measurement system was adopted. The measurement result shows that the real magnitude of axial electric field is smaller than that calculated, probably due to the actual pitch of the resister column which is much less than that of helix. (authors)

  18. Anastomotic leak detection by electrolyte electrical resistance.

    Science.gov (United States)

    DeArmond, Daniel T; Cline, Adam M; Johnson, Scott B

    2010-08-01

    To characterize a new method of postoperative gastrointestinal leak detection based on electrical resistance changes due to extravasated electrolyte contrast. Postoperative gastrointestinal leak results in increased patient morbidity, mortality, and hospital costs that can be mitigated by early diagnosis. A sensitive and specific diagnostic test that could be performed at the bedside has the potential to shorten the time to diagnosis and thereby improve the quality of treatment. Anaesthetized rats underwent celiotomy and creation of a 5-mm gastrotomy. In experimental animals, electrical resistance changes were measured with a direct current ohmmeter after the introduction of 5 cc of 23.4% NaCl electrolyte solution via gavage and measured with a more sensitive alternating current ohmmeter after the gavage of 1-5 cc of 0.9% NaCl. Comparison was made to negative controls and statistical analysis was performed. Leakage from the gastrotomy induced by as little as 1 cc of gavage-delivered 0.9% NaCl contrast solution was detectable as a statistically significant drop in electrical resistance when compared to results from negative controls. Electrical resistance change associated with electrolyte-gated leak detection is highly sensitive and specific and has the potential to be rapidly translated into clinical settings.

  19. Rapid hardening induced by electric pulse annealing in nanostructured pure aluminum

    DEFF Research Database (Denmark)

    Zeng, Wei; Shen, Yao; Zhang, Ning

    2012-01-01

    Nanostructured pure aluminum was fabricated by heavy cold-rolling and then subjected to recovery annealing either by applying electric pulse annealing or by traditional air furnace annealing. Both annealing treatments resulted in an increase in yield strength due to the occurrence of a “dislocation...... source-limited hardening” mechanism. However, the hardening kinetics was substantially faster for the electric pulse annealed material. Detailed microstructural characterization suggested that the rapid hardening during electric pulse annealing is related to an enhanced rate of recovery of dislocation...

  20. Pulsed chemical oxygen - iodine laser initiated by a transverse electric discharge

    International Nuclear Information System (INIS)

    Vagin, Nikolai P; Yuryshev, Nikolai N

    2001-01-01

    A pulsed chemical oxygen - iodine laser with a volume production of atomic iodine in a pulsed transverse electric discharge is studied. An increase in the partial oxygen pressure was shown to increase the pulse energy with retention of the pulse duration. At the same time, an increase in the iodide pressure and the discharge energy shortens the pulse duration. Pulses with a duration of 6.5 μs were obtained, which corresponds to a concentration of iodine atoms of 1.8 x 10 15 cm -3 . This concentration is close to the maximum concentration attained in studies of both cw and pulsed oxygen-iodine lasers. A specific energy output of 0.9 J litre -1 and a specific power of 75 kW litre -1 were obtained. The ways of increasing these parameters were indicated. It was found that SF 6 is an efficient buffer gas favouring improvements in the energy pulse parameters. (lasers)

  1. Pulsed Electrical Spin Injection into InGaAs Quantum Dots: Studies of the Electroluminescence Polarization Dynamics

    International Nuclear Information System (INIS)

    Asshoff, P.; Loeffler, W.; Fluegge, H.; Zimmer, J.; Mueller, J.; Westenfelder, B.; Hu, D. Z.; Schaadt, D. M.; Kalt, H.; Hetterich, M.

    2010-01-01

    We present time-resolved studies of the spin polarization dynamics during and after initialization through pulsed electrical spin injection into InGaAs quantum dots embedded in a p-i-n-type spin-injection light-emitting diode. Experiments are performed with pulse widths in the nanosecond range and a time-resolved single photon counting setup is used to detect the subsequent electroluminescence. We find evidence that the achieved spin polarization shows an unexpected temporal behavior, attributed mainly to many-carrier and non-equilibrium effects in the device.

  2. Transient Features in Nanosecond Pulsed Electric Fields Differentially Modulate Mitochondria and Viability

    Science.gov (United States)

    Beebe, Stephen J.; Chen, Yeong-Jer; Sain, Nova M.; Schoenbach, Karl H.; Xiao, Shu

    2012-01-01

    It is hypothesized that high frequency components of nanosecond pulsed electric fields (nsPEFs), determined by transient pulse features, are important for maximizing electric field interactions with intracellular structures. For monopolar square wave pulses, these transient features are determined by the rapid rise and fall of the pulsed electric fields. To determine effects on mitochondria membranes and plasma membranes, N1-S1 hepatocellular carcinoma cells were exposed to single 600 ns pulses with varying electric fields (0–80 kV/cm) and short (15 ns) or long (150 ns) rise and fall times. Plasma membrane effects were evaluated using Fluo-4 to determine calcium influx, the only measurable source of increases in intracellular calcium. Mitochondria membrane effects were evaluated using tetramethylrhodamine ethyl ester (TMRE) to determine mitochondria membrane potentials (ΔΨm). Single pulses with short rise and fall times caused electric field-dependent increases in calcium influx, dissipation of ΔΨm and cell death. Pulses with long rise and fall times exhibited electric field-dependent increases in calcium influx, but diminished effects on dissipation of ΔΨm and viability. Results indicate that high frequency components have significant differential impact on mitochondria membranes, which determines cell death, but lesser variances on plasma membranes, which allows calcium influxes, a primary determinant for dissipation of ΔΨm and cell death. PMID:23284682

  3. Energy and dose characteristics of ion bombardment during pulsed laser deposition of thin films under pulsed electric field

    International Nuclear Information System (INIS)

    Fominski, V.Yu.; Nevolin, V.N.; Smurov, I.

    2004-01-01

    Experiments on pulsed laser deposition of Fe films on Si substrates were performed with the aim to analyze the role of factors determining the formation of an energy spectrum and a dose of ions bombarding the film in strong pulsed electric fields. The amplitude of the high-voltage pulse (-40 kV) applied to the substrate and the laser fluence at the Fe target were fixed during the deposition. Owing to the high laser fluence (8 J/cm 2 ) at a relatively low power (20 mJ), the ionization of the laser plume was high, but the Fe vapor pressure near the substrate was low enough to avoid arcing. Electric signals from a target exposed to laser radiation were measured under different conditions (at different delay times) of application of electric pulses. The Si(100) substrates were analyzed using Rutherford ion backscattering/channeling spectrometry. The ion implantation dose occurred to be the highest if the high-voltage pulse was applied at a moment of time when the ion component of the plume approached the substrate. In this case, the implanted ions had the highest energy determined by the amplitude of the electric pulse. An advance or delay in applying a high-voltage pulse caused the ion dose and energy to decrease. A physical model incorporating three possible modes of ion implantation was proposed for the interpretation of the experimental results. If a laser plume was formed in the external field, ions were accelerated from the front of the dense plasma, and the ion current depended on the gas-dynamic expansion of the plume. The application of a high-voltage pulse, at the instant when the front approached the substrate, maintained the mode that was characteristic of the traditional plasma immersion ion implantation, and the ion current was governed by the dynamics of the plasma sheath in the substrate-to-target gap. In the case of an extremely late application of a high-voltage pulse, ions retained in the entire volume of the experimental chamber (as a result of the

  4. Effects of acoustic noise on the auditory nerve compound action potentials evoked by electric pulse trains.

    Science.gov (United States)

    Nourski, Kirill V; Abbas, Paul J; Miller, Charles A; Robinson, Barbara K; Jeng, Fuh-Cherng

    2005-04-01

    This study investigated the effects of acoustic noise on the auditory nerve compound action potentials in response to electric pulse trains. Subjects were adult guinea pigs, implanted with a minimally invasive electrode to preserve acoustic sensitivity. Electrically evoked compound action potentials (ECAP) were recorded from the auditory nerve trunk in response to electric pulse trains both during and after the presentation of acoustic white noise. Simultaneously presented acoustic noise produced a decrease in ECAP amplitude. The effect of the acoustic masker on the electric probe was greatest at the onset of the acoustic stimulus and it was followed by a partial recovery of the ECAP amplitude. Following cessation of the acoustic noise, ECAP amplitude recovered over a period of approximately 100-200 ms. The effects of the acoustic noise were more prominent at lower electric pulse rates (interpulse intervals of 3 ms and higher). At higher pulse rates, the ECAP adaptation to the electric pulse train alone was larger and the acoustic noise, when presented, produced little additional effect. The observed effects of noise on ECAP were the greatest at high electric stimulus levels and, for a particular electric stimulus level, at high acoustic noise levels.

  5. Validation of a pulsed electric field process to pasteurize strawberry puree

    Science.gov (United States)

    An inexpensive data acquisition method was developed to validate the exact number and shape of the pulses applied during pulsed electric fields (PEF) processing. The novel validation method was evaluated in conjunction with developing a pasteurization PEF process for strawberry puree. Both buffered...

  6. Pasteurization of strawberry puree using a pilot plant pulsed electric fields (PEF) system

    Science.gov (United States)

    The processing of strawberry puree by pulsed electric fields (PEF) in a pilot plant system has never been evaluated. In addition, a method does not exist to validate the exact number and shape of the pulses applied during PEF processing. Both buffered peptone water (BPW) and fresh strawberry puree (...

  7. Propagation of 1-THz bandwidth electrical pulses on high Tc superconducting transmission lines

    International Nuclear Information System (INIS)

    Nuss, M.C.; Mankiewich, P.M.; Howard, R.E.; Harvey, T.E.; Brandle, C.D.; Straugh, B.L.; Smith, P.R.

    1989-01-01

    The new high temperature superconductors have triggered enormous interest not only because of the unique physics involved but also because of their technical potentials, such as the promise for propagation of extremely short electrical pulses. Superconducting band caps of --20TH z are predicted assuming BCS theory for the superconductor, making lossless propagation of electrical pulses as short as 50 fs possible. Despite microwave measurements at low frequencies of several gigahertz first studies at higher frequencies by Dykaar et al have shown distortion-free propagation of 100-GHz electrical pulses on YBa 2 Cu 3 O 3 (YBCO) lines for --5-mm propagation distance. Results were also reported for aluminum coplanar lines and a YBCO ground plane. The authors report on the propagation of 1-ps electrical pulses (1-THz bandwidth) on YBCO coplanar transmission lines defined on lanthanum gallate (LaGaO 3 ) as a substrate. On LaGaO 3 , YBCO grows highly oriented as on SrTiO 3 . However, unlike SrTiO 3 , LaGaO 3 has a much lower dielectric constant and small losses in the terahertz frequency range. Electrical pulses of --750-fs duration are generated in a radiation-damaged silicon-on-sapphire photoconductive switch integrated into a 20-μm coplanar stripline with 10-μm spacing and excited with 100-fs optical pulses from a CPM laser. An μ1-THz bandwidth electrical contact is made to the YBCO coplanar stripline defined on LaGaO 3 using a flip-chip geometry. They find that electrical pulses broaden only from 750 fs to 1 ps with little loss in amplitude on traveling through their flip-chip input and propagated electrical pulses are probed by electooptic sampling in two small LiTaO 3 crystals separated by 3 mm

  8. Activation of Anti-tumor Immune Response by Ablation of HCC with Nanosecond Pulsed Electric Field.

    Science.gov (United States)

    Xu, Xiaobo; Chen, Yiling; Zhang, Ruiqing; Miao, Xudong; Chen, Xinhua

    2018-03-28

    Locoregional therapy is playing an increasingly important role in the non-surgical management of hepatocellular carcinoma (HCC). The novel technique of non-thermal electric ablation by nanosecond pulsed electric field has been recognized as a potential locoregional methodology for indicated HCC. This manuscript explores the most recent studies to indicate its unique anti-tumor immune response. The possible immune mechanism, termed as nano-pulse stimulation, was also analyzed.

  9. Time-resolved processes in a pulsed electrical discharge in argon bubbles in water

    Science.gov (United States)

    Gershman, S.; Belkind, A.

    2010-12-01

    A phenomenological picture of a pulsed electrical discharge in gas bubbles in water is produced by combining electrical, spectroscopic, and imaging characterization methods. The discharge is generated by applying 1 μ s pulses of 5 to 20 kV between a needle and a disk electrode submerged in water. An Ar gas bubble surrounds the tip of the needle electrode. Imaging, electrical characteristics, and time-resolved optical emission spectroscopic data suggest a fast streamer propagation mechanism and the formation of a plasma channel in the bubble. Comparing the electrical and imaging data for consecutive pulses applied to the bubble at a frequency of 1 Hz indicates that each discharge proceeds as an entirely new process with no memory of the previous discharge aside from the presence of long-lived chemical species, such as ozone and oxygen. Imaging and electrical data show the presence of two discharge events during each applied voltage pulse, a forward discharge near the beginning of the applied pulse depositing charge on the surface of the bubble and a reverse discharge removing the accumulated charge from the water/gas interface when the applied voltage is turned off. The pd value of ~ 300-500 torr cm, the 1 μs long pulse duration, low repetition rate, and unidirectional character of the applied voltage pulses make the discharge process here unique compared to the traditional corona or dielectric barrier discharges.

  10. Response of larval sea lampreys (Petromyzon marinus) to pulsed DC electrical stimuli in laboratory experiments

    Science.gov (United States)

    Bowen, Anjanette K.; Weisser, John W.; Bergstedt, Roger A.; Famoye, Felix

    2003-01-01

    Four electrical factors that are used in pulsed DC electrofishing for larval sea lampreys (Petromyzon marinus) were evaluated in two laboratory studies to determine the optimal values to induce larval emergence over a range of water temperatures and conductivities. Burrowed larvae were exposed to combinations of pulsed DC electrical factors including five pulse frequencies, three pulse patterns, and two levels of duty cycle over a range of seven voltage gradients in two separate studies conducted at water temperatures of 10, 15, and 20°C and water conductivities of 25, 200, and 900 μS/cm. A four-way analysis of variance was used to determine significant (α = 0.05) influences of each electrical factor on larval emergence. Multiple comparison tests with Bonferroni adjustments were used to determine which values of each factor resulted in significantly higher emergence at each temperature and conductivity. Voltage gradient and pulse frequency significantly affected emergence according to the ANOVA model at each temperature and conductivity tested. Duty cycle and pulse pattern generally did not significantly influence the model. Findings suggest that a setting of 2.0 V/cm, 3 pulses/sec, 10% duty, and 2:2 pulse pattern seems the most promising in waters of medium conductivity and across a variety of temperatures. This information provides a basis for understanding larval response to pulsed DC electrofishing gear factors and identifies electrofisher settings that show promise to increase the efficiency of the gear during assessments for burrowed sea lamprey larvae.

  11. Two modes of cell death caused by exposure to nanosecond pulsed electric field.

    Directory of Open Access Journals (Sweden)

    Olga N Pakhomova

    Full Text Available High-amplitude electric pulses of nanosecond duration, also known as nanosecond pulsed electric field (nsPEF, are a novel modality with promising applications for cell stimulation and tissue ablation. However, key mechanisms responsible for the cytotoxicity of nsPEF have not been established. We show that the principal cause of cell death induced by 60- or 300-ns pulses in U937 cells is the loss of the plasma membrane integrity ("nanoelectroporation", leading to water uptake, cell swelling, and eventual membrane rupture. Most of this early necrotic death occurs within 1-2 hr after nsPEF exposure. The uptake of water is driven by the presence of pore-impermeable solutes inside the cell, and can be counterbalanced by the presence of a pore-impermeable solute such as sucrose in the medium. Sucrose blocks swelling and prevents the early necrotic death; however the long-term cell survival (24 and 48 hr does not significantly change. Cells protected with sucrose demonstrate higher incidence of the delayed death (6-24 hr post nsPEF. These cells are more often positive for the uptake of an early apoptotic marker dye YO-PRO-1 while remaining impermeable to propidium iodide. Instead of swelling, these cells often develop apoptotic fragmentation of the cytoplasm. Caspase 3/7 activity increases already in 1 hr after nsPEF and poly-ADP ribose polymerase (PARP cleavage is detected in 2 hr. Staurosporin-treated positive control cells develop these apoptotic signs only in 3 and 4 hr, respectively. We conclude that nsPEF exposure triggers both necrotic and apoptotic pathways. The early necrotic death prevails under standard cell culture conditions, but cells rescued from the necrosis nonetheless die later on by apoptosis. The balance between the two modes of cell death can be controlled by enabling or blocking cell swelling.

  12. Pulsed eddy current differential probe to detect the defects in a stainless steel pipe

    Science.gov (United States)

    Angani, C. S.; Park, D. G.; Kim, C. G.; Leela, P.; Kishore, M.; Cheong, Y. M.

    2011-04-01

    Pulsed eddy current (PEC) is an electromagnetic nondestructive technique widely used to detect and quantify the flaws in conducting materials. In the present study a differential Hall-sensor probe which is used in the PEC system has been fabricated for the detection of defects in stainless steel pipelines. The differential probe has an exciting coil with two Hall-sensors. A stainless steel test sample with electrical discharge machining (EDM) notches under different depths of 1-5 mm was made and the sample was laminated by plastic insulation having uniform thickness to simulate the pipelines in nuclear power plants (NPPs). The driving coil in the probe is excited by a rectangular current pulse and the resultant response, which is the difference of the two Hall-sensors, has been detected as the PEC probe signal. The discriminating time domain features of the detected pulse such as peak value and time to zero are used to interpret the experimental results with the defects in the test sample. A feature extraction technique such as spectral power density has been devised to infer the PEC response.

  13. Transmembrane molecular transport during versus after extremely large, nanosecond electric pulses.

    Science.gov (United States)

    Smith, Kyle C; Weaver, James C

    2011-08-19

    Recently there has been intense and growing interest in the non-thermal biological effects of nanosecond electric pulses, particularly apoptosis induction. These effects have been hypothesized to result from the widespread creation of small, lipidic pores in the plasma and organelle membranes of cells (supra-electroporation) and, more specifically, ionic and molecular transport through these pores. Here we show that transport occurs overwhelmingly after pulsing. First, we show that the electrical drift distance for typical charged solutes during nanosecond pulses (up to 100 ns), even those with very large magnitudes (up to 10 MV/m), ranges from only a fraction of the membrane thickness (5 nm) to several membrane thicknesses. This is much smaller than the diameter of a typical cell (∼16 μm), which implies that molecular drift transport during nanosecond pulses is necessarily minimal. This implication is not dependent on assumptions about pore density or the molecular flux through pores. Second, we show that molecular transport resulting from post-pulse diffusion through minimum-size pores is orders of magnitude larger than electrical drift-driven transport during nanosecond pulses. While field-assisted charge entry and the magnitude of flux favor transport during nanosecond pulses, these effects are too small to overcome the orders of magnitude more time available for post-pulse transport. Therefore, the basic conclusion that essentially all transmembrane molecular transport occurs post-pulse holds across the plausible range of relevant parameters. Our analysis shows that a primary direct consequence of nanosecond electric pulses is the creation (or maintenance) of large populations of small pores in cell membranes that govern post-pulse transmembrane transport of small ions and molecules. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Detection of the Typical Pulse Condition on Cun-Guan-Chi Based on Image Sensor

    Directory of Open Access Journals (Sweden)

    Aihua ZHANG

    2014-02-01

    Full Text Available In order to simulate the diagnosis by feeling the pulse with Traditional Chinese Medicine, a device based on CCD was designed to detect the pulse image of Cun-Guan-Chi. Using the MM-3 pulse model as experimental subject, the synchronous pulse image data of some typical pulse condition were collected by this device on Cun-Guan-Chi. The typical pulses include the normal pulse, the slippery pulse, the slow pulse and the soft pulse. According to the lens imaging principle, the pulse waves were extracted by using the area method, then the 3D pulse condition image was restructured and some features were extracted including the period, the frequency, the width, and the length. The slippery pulse data of pregnant women were collected by this device, and the pulse images were analyzed. The results are consistent based on comparing the features of the slippery pulse model with the slippery pulse of pregnant women. This study overcame shortages of the existing detection device such as the few detecting parts and the limited information, and more comprehensive 3D pulse condition information could be obtained. This work laid a foundation for realizing the objective diagnosis and revealing the comprehensive information of the pulse.

  15. Eradication of multidrug-resistant A. baumannii in burn wounds by antiseptic pulsed electric field

    Science.gov (United States)

    Golberg, Alexander; Broelsch, G. Felix; Vecchio, Daniela; Khan, Saiqa; Hamblin, Michael R.; Austen, William G.; Sheridan, Robert L.; Yarmush, Martin L.

    2014-01-01

    Emerging bacterial resistance to multiple drugs is an increasing problem in burn wound management. New non-pharmacologic interventions are needed for burn wound disinfection. Here we report on a novel physical method for disinfection: antiseptic pulsed electric field (PEF) applied externally to the infected burns. In a mice model, we show that PEF can reduce the load of multidrug resistant Acinetobacter baumannii present in a full thickness burn wound by more than four orders of magnitude, as detected by bioluminescence imaging. Furthermore, using a finite element numerical model, we demonstrate that PEF provides non-thermal, homogeneous, full thickness treatment for the burn wound, thus, overcoming the limitation of treatment depth for many topical antimicrobials. These modeling tools and our in vivo results will be extremely useful for further translation of the PEF technology to the clinical setting, as they provide the essential elements for planning of electrode design and treatment protocol. PMID:25089285

  16. Detection of Individual Molecules and Ions by Carbon Nanotube-Based Differential Resistive Pulse Sensor.

    Science.gov (United States)

    Peng, Ran; Tang, Xiaowu Shirley; Li, Dongqing

    2018-04-01

    This paper presents a new method of sensing single molecules and cations by a carbon nanotube (CNT)-based differential resistive pulse sensing (RPS) technique on a nanofluidic chip. A mathematical model for multichannel RPS systems is developed to evaluate the CNT-based RPS signals. Individual cations, rhodamine B dye molecules, and ssDNAs are detected successfully with high resolution and high signal-to-noise ratio. Differentiating ssDNAs with 15 and 30 nucleotides are achieved. The experimental results also show that translocation of negatively charged ssDNAs through a CNT decreases the electrical resistance of the CNT channel, while translocation of positively charged cations and rhodamine B molecules increases the electrical resistance of the CNT. The CNT-based nanofluidic device developed in this work provides a new avenue for single-molecule/ion detection and offers a potential strategy for DNA sequencing. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. [Negative air ions generated by plants upon pulsed electric field stimulation applied to soil].

    Science.gov (United States)

    Wu, Ren-ye; Deng, Chuan-yuan; Yang, Zhi-jian; Weng, Hai-yong; Zhu, Tie-jun-rong; Zheng, Jin-gui

    2015-02-01

    This paper investigated the capacity of plants (Schlumbergera truncata, Aloe vera var. chinensis, Chlorophytum comosum, Schlumbergera bridgesii, Gymnocalycium mihanovichii var. friedrichii, Aspidistra elatior, Cymbidium kanran, Echinocactus grusonii, Agave americana var. marginata, Asparagus setaceus) to generate negative air ions (NAI) under pulsed electric field stimulation. The results showed that single plant generated low amounts of NAI in natural condition. The capacity of C. comosum and G. mihanovichii var. friedrichii generated most NAI among the above ten species, with a daily average of 43 ion · cm(-3). The least one was A. americana var. marginata with the value of 19 ion · cm(-3). When proper pulsed electric field stimulation was applied to soil, the NAI of ten plant species were greatly improved. The effect of pulsed electric field u3 (average voltage over the pulse period was 2.0 x 10(4) V, pulse frequency was 1 Hz, and pulse duration was 50 ms) was the greatest. The mean NAI concentration of C. kanran was the highest 1454967 ion · cm(-3), which was 48498.9 times as much as that in natural condition. The lowest one was S. truncata with the value of 34567 ion · cm(-3), which was 843.1 times as much as that in natural condition. The capacity of the same plants to generate negative air ion varied extremely under different intensity pulsed electric fields.

  18. Treatment of complex biological mixtures with pulsed electric fields An energy transfer characterization

    International Nuclear Information System (INIS)

    Schrive, Luc

    2004-01-01

    Sewage sludge from waste water treatment plants is a complex biological mixture and a problematic by-product because of valorisation restrictions. In order to limit its production, pulsed electric fields (PEF) were studied because of their biological effects and their potentially physico-chemical action. This work demonstrated a paradoxical phenomenon: cell lysis triggered a respirometric activation followed by a delayed lethality. This phenomenon was related to the leakage of internal compounds which were immediately bio-assimilated. At high energy expense, the plasmic membrane permeabilization led to cell death. Practically, with the technical configuration of the equipment, no hydrolysis was detected. This limitation decreases the interest for excess sludge reduction, but for the same reason, PEF cold sterilization technique can be assessed as a promising process. The representation of the electric energy transfer from electrodes to cell was exchanged by the study of mass transfer from the biological cell to the surrounding media under an electromotive force. Thus, the survival rate was modelled by a Sherwood number taking account of electrical, biological and hydraulic parameters. (author) [fr

  19. Exploring the effects of pulsed electric field processing parameters on polyacetylene extraction from carrot slices.

    Science.gov (United States)

    Aguiló-Aguayo, Ingrid; Abreu, Corina; Hossain, Mohammad B; Altisent, Rosa; Brunton, Nigel; Viñas, Inmaculada; Rai, Dilip K

    2015-03-02

    The effects of various pulsed electric field (PEF) parameters on the extraction of polyacetylenes from carrot slices were investigated. Optimised conditions with regard to electric field strength (1-4 kV/cm), number of pulses (100-1500), pulse frequency (10-200 Hz) and pulse width (10-30 μs) were identified using response surface methodology (RSM) to maximise the extraction of falcarinol (FaOH), falcarindiol (FaDOH) and falcarindiol-3-acetate (FaDOAc) from carrot slices. Data obtained from RSM and experiments fitted significantly (p pulses of 10 μs at 10 Hz. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values with low average mean deviations (E%) ranging from 0.68% to 3.58%.

  20. Breakdown in ZnO Varistors by High Power Electrical Pulses; TOPICAL

    International Nuclear Information System (INIS)

    PIKE, GORDON E.

    2001-01-01

    This report documents an investigation of irreversible electrical breakdown in ZnO varistors due to short pulses of high electric field and current density. For those varistors that suffer breakdown, there is a monotonic, pulse-by-pulse degradation in the switching electric field. The electrical and structural characteristics of varistors during and after breakdown are described qualitatively and quantitatively. Once breakdown is nucleated, the degradation typically follows a well-defined relationship between the number of post-initiation pulses and the degraded switching voltage. In some cases the degraded varistor has a remnant 20(micro)m diameter hollow track showing strong evidence of once-molten ZnO. A model is developed for both electrical and thermal effects during high energy pulsing. The breakdown is assumed to start at one electrode and advance towards the other electrode as a thin filament of conductive material that grows incrementally with each successive pulse. The model is partially validated by experiments in which the varistor rod is cut at several different lengths from the electrode. Invariably one section of the cut varistor has a switching field that is not degraded while the other section(s) are heavily degraded. Based on the experiments and models of behavior during breakdown, some speculations about the nature of the nucleating mechanism are offered in the last section

  1. Predicting the threshold of pulse-train electrical stimuli using a stochastic auditory nerve model: the effects of stimulus noise.

    Science.gov (United States)

    Xu, Yifang; Collins, Leslie M

    2004-04-01

    The incorporation of low levels of noise into an electrical stimulus has been shown to improve auditory thresholds in some human subjects (Zeng et al., 2000). In this paper, thresholds for noise-modulated pulse-train stimuli are predicted utilizing a stochastic neural-behavioral model of ensemble fiber responses to bi-phasic stimuli. The neural refractory effect is described using a Markov model for a noise-free pulse-train stimulus and a closed-form solution for the steady-state neural response is provided. For noise-modulated pulse-train stimuli, a recursive method using the conditional probability is utilized to track the neural responses to each successive pulse. A neural spike count rule has been presented for both threshold and intensity discrimination under the assumption that auditory perception occurs via integration over a relatively long time period (Bruce et al., 1999). An alternative approach originates from the hypothesis of the multilook model (Viemeister and Wakefield, 1991), which argues that auditory perception is based on several shorter time integrations and may suggest an NofM model for prediction of pulse-train threshold. This motivates analyzing the neural response to each individual pulse within a pulse train, which is considered to be the brief look. A logarithmic rule is hypothesized for pulse-train threshold. Predictions from the multilook model are shown to match trends in psychophysical data for noise-free stimuli that are not always matched by the long-time integration rule. Theoretical predictions indicate that threshold decreases as noise variance increases. Theoretical models of the neural response to pulse-train stimuli not only reduce calculational overhead but also facilitate utilization of signal detection theory and are easily extended to multichannel psychophysical tasks.

  2. Ultrafast Electric Field Pulse Control of Giant Temperature Change in Ferroelectrics

    Science.gov (United States)

    Qi, Y.; Liu, S.; Lindenberg, A. M.; Rappe, A. M.

    2018-01-01

    There is a surge of interest in developing environmentally friendly solid-state-based cooling technology. Here, we point out that a fast cooling rate (≈1011 K /s ) can be achieved by driving solid crystals to a high-temperature phase with a properly designed electric field pulse. Specifically, we predict that an ultrafast electric field pulse can cause a giant temperature decrease up to 32 K in PbTiO3 occurring on few picosecond time scales. We explain the underlying physics of this giant electric field pulse-induced temperature change with the concept of internal energy redistribution: the electric field does work on a ferroelectric crystal and redistributes its internal energy, and the way the kinetic energy is redistributed determines the temperature change and strongly depends on the electric field temporal profile. This concept is supported by our all-atom molecular dynamics simulations of PbTiO3 and BaTiO3 . Moreover, this internal energy redistribution concept can also be applied to understand electrocaloric effect. We further propose new strategies for inducing giant cooling effect with ultrafast electric field pulse. This Letter offers a general framework to understand electric-field-induced temperature change and highlights the opportunities of electric field engineering for controlled design of fast and efficient cooling technology.

  3. Detection of weak electric fields by sharks, rays, and skates.

    Science.gov (United States)

    Adair, Robert K.; Astumian, R. Dean; Weaver, James C.

    1998-09-01

    The elasmobranchs-sharks, rays, and skates-can detect very weak electric fields in their aqueous environment through a complex sensory system, the ampullae of Lorenzini. The ampullae are conducting tubes that connect the surface of the animal to its interior. In the presence of an electric field, the potential of the surface of the animal will differ from that of the interior and that potential is applied across the apical membrane of the special sensory cells that line the ampullae. The firing rate of the afferent neurons that transmit signals from the ampullae has been shown to vary with that potential. We show that those firing rates can be described quantitatively in terms of synchronous firing of the sensory cells that feed the neurons. We demonstrate that such synchronism follows naturally from a hypothetical weak cell-to-cell interaction that results in a self-organization of the sensory cells. Moreover, the pulse rates of those cells-and the neurons that service the cells-can be expected to vary with the imposed electric fields in accord with measured values through actions of voltage gated transmembrane proteins in the apical sector of the cell membranes that admit Ca(++) ions. We also present a more conjectural model of signal processing at the neuron level that could exploit small differences in firing rates of nerve fibers servicing different ampullae to send an unambiguous signal to the central nervous system of the animal. (c) 1998 American Institute of Physics.

  4. Concrete deterioration: detection by ultrasonic pulse velocity method

    International Nuclear Information System (INIS)

    Sutan, N.M.; Jaafar, M.S.; Hamdan, S.

    2003-01-01

    Tests were performed to evaluate the feasibility of using Ultrasonic Pulse Velocity Method (UPVM) in detecting defect and determining its depth during the early age concrete. Five reinforced concrete (RC) slabs of grade 30, 40 and 50 specimens at day 3, 7,14 and 28 with a fabricated void at a known location were used. The results obtained were compared to determine the accuracy of the method hence the effectiveness of the method with different strength and as the concrete matures. This method detects defects in specimens during the early age The accuracy varies with concrete strength and as the concrete mature. The test results indicate the method can be used to assess the in-situ properties of concrete or for quality control on site. The method showed better accuracy with stronger concrete detects defects with the accuracy ranging from 55.75-99.62% from day 3-28 (full strength) respectively. (author)

  5. Metal release in a stainless steel Pulsed Electric Field (PEF) system Part I. Effect of different pulse shapes; theory and experimental method

    NARCIS (Netherlands)

    Roodenburg, B.; Morren, J.; Berg, H.E.; Haan, S.W.H.de

    2005-01-01

    Liquid pumpable food is mostly pasteurised by heat treatment. In the last decennia there is an increasing interest in so-called Pulsed Electric Field (PEF) treatment. During this treatment food is pumped between two metal electrodes and exposed to short high electric field pulses, typical 2-4 kV

  6. Electrically Excited Plasmonic Nanoruler for Biomolecule Detection.

    Science.gov (United States)

    Dathe, André; Ziegler, Mario; Hübner, Uwe; Fritzsche, Wolfgang; Stranik, Ondrej

    2016-09-14

    Plasmon-based sensors are excellent tools for a label-free detection of small biomolecules. An interesting group of such sensors are plasmonic nanorulers that rely on the plasmon hybridization upon modification of their morphology to sense nanoscale distances. Sensor geometries based on the interaction of plasmons in a flat metallic layer together with metal nanoparticles inherit unique advantages but need a special optical excitation configuration that is not easy to miniaturize. Herein, we introduce the concept of nanoruler excitation by direct, electrically induced generation of surface plasmons based on the quantum shot noise of tunneling currents. An electron tunneling junction consisting of a metal-dielectric-semiconductor heterostructure is directly incorporated into the nanoruler basic geometry. With the application of voltage on this modified nanoruler, the plasmon modes are directly excited without any additional optical component as a light source. We demonstrate via several experiments that this electrically driven nanoruler possesses similar properties as an optically exited one and confirm its sensing capabilities by the detection of the binding of small biomolecules such as antibodies. This new sensing principle could open the way to a new platform of highly miniaturized, integrated plasmonic sensors compatible with monolithic integrated circuits.

  7. Improved Pulse Detection from Head Motions Using DCT

    DEFF Research Database (Denmark)

    Irani, Ramin; Nasrollahi, Kamal; Moeslund, Thomas B.

    2014-01-01

    . To measure it, physicians traditionally, either sense the pulsations of some blood vessels or install some sensors on the body. In either case, there is a need for a physical contact between the sensor and the body to obtain the heartbeat rate. This might not be always feasible, for example, for applications......The heart pulsation sends out the blood throughout the body. The rate in which the heart performs this vital task, heartbeat rate, is of curial importance to the body. Therefore, measuring heartbeat rate, a.k.a. pulse detection, is very important in many applications, especially the medical ones...

  8. Pulse-voltammetric glucose detection at gold junction electrodes.

    Science.gov (United States)

    Rassaei, Liza; Marken, Frank

    2010-09-01

    A novel glucose sensing concept based on the localized change or "modulation" in pH within a symmetric gold-gold junction electrode is proposed. A paired gold-gold junction electrode (average gap size ca. 500 nm) is prepared by simultaneous bipotentiostatic electrodeposition of gold onto two closely spaced platinum disk electrodes. For glucose detection in neutral aqueous solution, the potential of the "pH-modulator" electrode is set to -1.5 V vs saturated calomel reference electrode (SCE) to locally increase the pH, and simultaneously, either cyclic voltammetry or square wave voltammetry experiments are conducted at the sensor electrode. A considerable improvement in the sensor electrode response is observed when a normal pulse voltammetry sequence is applied to the modulator electrode (to generate "hydroxide pulses") and the glucose sensor electrode is operated with fixed bias at +0.5 V vs SCE (to eliminate capacitive charging currents). Preliminary data suggest good linearity for the glucose response in the medically relevant 1-10 mM concentration range (corresponding to 0.18-1.8 g L(-1)). Future electroanalytical applications of multidimensional pulse voltammetry in junction electrodes are discussed.

  9. Electric field measurements in a dielectric barrier nanosecond pulse discharge with sub-nanosecond time resolution

    International Nuclear Information System (INIS)

    Goldberg, Benjamin M; Shkurenkov, Ivan; Adamovich, Igor V; Lempert, Walter R; O’Byrne, Sean

    2015-01-01

    The paper presents the results of time-resolved electric field measurements in a nanosecond discharge between two plane electrodes covered by dielectric plates, using picosecond four-wave mixing diagnostics. For absolute calibration, the IR signal was measured in hydrogen at a pressure of 440 Torr, for electrostatic electric field ranging from 0 to 8 kV cm −1 . The calibration curve (i.e. the square root of IR signal intensity versus electric field) was shown to be linear. By measuring the intensities of the pump, Stokes, and IR signal beam for each laser shot during the time sweep across the high-voltage pulse, temporal evolution of the electric field in the nanosecond pulse discharge was determined with sub-nanosecond time resolution. The results are compared to kinetic modeling predictions, showing good agreement, including non-zero electric field offset before the main high voltage pulse, breakdown moment, and reduction of electric field in the plasma after breakdown. The difference between the experimental results and model predictions is likely due to non-1D structure of the discharge. Comparison with the kinetic modeling predictions shows that electric field in the nanosecond pulse discharge is controlled primarily by electron impact excitation and charge accumulation on the dielectric surfaces. (paper)

  10. Electric field induced needle-pulsed arc discharge carbon nanotube production apparatus: Circuitry and mechanical design

    Energy Technology Data Exchange (ETDEWEB)

    Kia, Kaveh Kazemi [Department of Electrical and Computer Engineering, Islamic Azad University of Bonab, Bonab (Iran, Islamic Republic of); Bonabi, Fahimeh [Department of Engineering, Islamic Azad University of Bonab, Bonab (Iran, Islamic Republic of)

    2012-12-15

    A simple and low cost apparatus is reported to produce multiwall carbon nanotubes and carbon nano-onions by a low power short pulsed arc discharge reactor. The electric circuitry and the mechanical design details and a micro-filtering assembly are described. The pulsed-plasma is generated and applied between two graphite electrodes. The pulse width is 0.3 {mu}s. A strong dc electric field is established along side the electrodes. The repetitive discharges occur in less than 1 mm distance between a sharp tip graphite rod as anode, and a tubular graphite as cathode. A hydrocarbon vapor, as carbon source, is introduced through the graphite nozzle in the cathode assembly. The pressure of the chamber is controlled by a vacuum pump. A magnetic field, perpendicular to the plasma path, is provided. The results show that the synergetic use of a pulsed-current and a dc power supply enables us to synthesize carbon nanoparticles with short pulsed plasma. The simplicity and inexpensiveness of this plan is noticeable. Pulsed nature of plasma provides some extra degrees of freedom that make the production more controllable. Effects of some design parameters such as electric field, pulse frequency, and cathode shape are discussed. The products are examined using scanning probe microscopy techniques.

  11. Electric field induced needle-pulsed arc discharge carbon nanotube production apparatus: circuitry and mechanical design.

    Science.gov (United States)

    Kia, Kaveh Kazemi; Bonabi, Fahimeh

    2012-12-01

    A simple and low cost apparatus is reported to produce multiwall carbon nanotubes and carbon nano-onions by a low power short pulsed arc discharge reactor. The electric circuitry and the mechanical design details and a micro-filtering assembly are described. The pulsed-plasma is generated and applied between two graphite electrodes. The pulse width is 0.3 μs. A strong dc electric field is established along side the electrodes. The repetitive discharges occur in less than 1 mm distance between a sharp tip graphite rod as anode, and a tubular graphite as cathode. A hydrocarbon vapor, as carbon source, is introduced through the graphite nozzle in the cathode assembly. The pressure of the chamber is controlled by a vacuum pump. A magnetic field, perpendicular to the plasma path, is provided. The results show that the synergetic use of a pulsed-current and a dc power supply enables us to synthesize carbon nanoparticles with short pulsed plasma. The simplicity and inexpensiveness of this plan is noticeable. Pulsed nature of plasma provides some extra degrees of freedom that make the production more controllable. Effects of some design parameters such as electric field, pulse frequency, and cathode shape are discussed. The products are examined using scanning probe microscopy techniques.

  12. The second phase of bipolar, nanosecond-range electric pulses determines the electroporation efficiency.

    Science.gov (United States)

    Pakhomov, Andrei G; Grigoryev, Sergey; Semenov, Iurii; Casciola, Maura; Jiang, Chunqi; Xiao, Shu

    2018-03-29

    Bipolar cancellation refers to a phenomenon when applying a second electric pulse reduces ("cancels") cell membrane damage by a preceding electric pulse of the opposite polarity. Bipolar cancellation is a reason why bipolar nanosecond electric pulses (nsEP) cause weaker electroporation than just a single unipolar phase of the same pulse. This study was undertaken to explore the dependence of bipolar cancellation on nsEP parameters, with emphasis on the amplitude ratio of two opposite polarity phases of a bipolar pulse. Individual cells (CHO, U937, or adult mouse ventricular cardiomyocytes (VCM)) were exposed to either uni- or bipolar trapezoidal nsEP, or to nanosecond electric field oscillations (NEFO). The membrane injury was evaluated by time-lapse confocal imaging of the uptake of propidium (Pr) or YO-PRO-1 (YP) dyes and by phosphatidylserine (PS) externalization. Within studied limits, bipolar cancellation showed little or no dependence on the electric field intensity, pulse repetition rate, chosen endpoint, or cell type. However, cancellation could increase for larger pulse numbers and/or for longer pulses. The sole most critical parameter which determines bipolar cancellation was the phase ratio: maximum cancellation was observed with the 2nd phase of about 50% of the first one, whereas a larger 2nd phase could add a damaging effect of its own. "Swapping" the two phases, i.e., delivering the smaller phase before the larger one, reduced or eliminated cancellation. These findings are discussed in the context of hypothetical mechanisms of bipolar cancellation and electroporation by nsEP. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. The influence of stellate ganglion transcutaneous electrical nerve stimulation on signal quality of pulse oximetry in prehospital trauma care.

    Science.gov (United States)

    Barker, Renate; Lang, Thomas; Hager, Helmut; Steinlechner, Barbara; Hoerauf, Klaus; Zimpfer, Michael; Kober, Alexander

    2007-05-01

    Accurate monitoring of the peripheral arterial oxygen saturation has become an important tool in the prehospital emergency medicine. This monitoring requires an adequate plethysmographic pulsation. Signal quality is diminished by cold ambient temperature due to vasoconstriction. Blockade of the stellate ganglion can improve peripheral vascular perfusion and can be achieved by direct injection or transcutaneous electrical nerve stimulation (TENS) stimulation. We evaluated whether TENS on the stellate ganglion would reduce vasoconstriction and thereby improve signal detection quality of peripheral pulse oximetry. In our study, 53 patients with minor trauma who required transport to the hospital were enrolled. We recorded vital signs, including core and skin temperature before and after transport to the hospital. Pulse oximetry sensors were attached to the patient's second finger on both hands. TENS of the stellate ganglion was started on one side after the beginning of the transport. Pulse oximeter alerts, due to poor signal detection, were recorded for each side separately. On the hand treated with TENS we detected a significant reduction of alerts compared to the other side (mean alerts TENS 3.1 [1-15] versus control side 8.8 [1-28] P signal quality of pulse oximeters in the prehospital setting.

  14. Process Control of Pre-Sowing Seed Treatment by Pulsed Electric Field

    Directory of Open Access Journals (Sweden)

    Starodubtseva Galina Petrovna

    2018-03-01

    Full Text Available Presented paper investigates the application of a line voltage changer to an installation for pre-sowing seed treatment by pulsed electric field (PEF in order to increase the sowing quality of seeds and to suppress pathogenic microflora. The installation comprises an AC voltage regulator, a high voltage source, a voltage inverter, a working chamber for seed treatment, a control unit, and current and voltage sensors. The proposed installation differs from the existing apparatuses as it automatically provides the transformation of the pulsed electric field parameters by constant monitoring of power processes in a layer of treated seeds and feedback sending to the control unit. Seed treatment efficiency depends on the dose being determined by the parameters of electric field, namely, intensity in the seed layer, pulse duration, pulse repetition frequency, and seed treatment time. The parameters of rational treatment were determined, and the minimum treatment dose was calculated on the basis of results from the laboratory tests on the effect of pulsed electric field on sowing qualities of winter wheat seeds. It was experimentally confirmed that the proposed installation provides automatic transformation of electric field parameters depending on the changes taking place in the seed layer on the example of seeds with different moisture content maintaining the necessary treatment dose, ensuring the stability and repeatability of results.

  15. Optimized extraction of polysaccharides from corn silk by pulsed electric field and response surface quadratic design.

    Science.gov (United States)

    Zhao, Wenzhu; Yu, Zhipeng; Liu, Jingbo; Yu, Yiding; Yin, Yongguang; Lin, Songyi; Chen, Feng

    2011-09-01

    Corn silk is a traditional Chinese herbal medicine, which has been widely used for treatment of some diseases. In this study the effects of pulsed electric field on the extraction of polysaccharides from corn silk were investigated. Polysaccharides in corn silk were extracted by pulsed electric field and optimized by response surface methodology (RSM), based on a Box-Behnken design (BBD). Three independent variables, including electric field intensity (kV cm(-1) ), ratio of liquid to raw material and pulse duration (µs), were investigated. The experimental data were fitted to a second-order polynomial equation and also profiled into the corresponding 3-D contour plots. Optimal extraction conditions were as follows: electric field intensity 30 kV cm(-1) , ratio of liquid to raw material 50, and pulse duration 6 µs. Under these condition, the experimental yield of extracted polysaccharides was 7.31% ± 0.15%, matching well with the predicted value. The results showed that a pulsed electric field could be applied to extract value-added products from foods and/or agricultural matrix. Copyright © 2011 Society of Chemical Industry.

  16. A correlation-based pulse detection technique for gamma-ray/neutron detectors

    International Nuclear Information System (INIS)

    Faisal, Muhammad; Schiffer, Randolph T.; Flaska, Marek; Pozzi, Sara A.; Wentzloff, David D.

    2011-01-01

    We present a correlation-based detection technique that significantly improves the probability of detection for low energy pulses. We propose performing a normalized cross-correlation of the incoming pulse data to a predefined pulse template, and using a threshold correlation value to trigger the detection of a pulse. This technique improves the detector sensitivity by amplifying the signal component of incoming pulse data and rejecting noise. Simulation results for various different templates are presented. Finally, the performance of the correlation-based detection technique is compared to the current state-of-the-art techniques.

  17. Determination of electric field threshold for electrofusion of erythrocyte ghosts. Comparison of pulse-first and contact-first protocols.

    OpenAIRE

    Wu, Y; Montes, J G; Sjodin, R A

    1992-01-01

    Rabbit erythrocyte ghosts were fused by means of electric pulses to determine the electrofusion thresholds for these membranes. Two protocols were used to investigate fusion events: contact-first, and pulse-first. Electrical capacitance discharge (CD) pulses were used to induce fusion. Plots of fusion yield vs peak field strength yielded curves that intersected the field strength axis at positive values (pseudothresholds) which depended on the protocol and decay half time of the pulses. It wa...

  18. Growth and apoptosis of HeLa cells induced by intense picosecond pulsed electric field

    Directory of Open Access Journals (Sweden)

    Yuan-yuan HUA

    2011-07-01

    Full Text Available Objective To investigate the growth and apoptosis of HeLa cells induced by intense picosecond pulsed electric field(PEF in vitro.Methods HeLa cells cultured in vitro were divided into experimental group and control group(with or without intense picosecond PEF.With constant pulse width,frequency and voltage,the cells in experimental group were divided into 6 sub-groups according to the number of pulse(100,200,500,1000,1500,2000,the growth inhibition of HeLa cells by PEF and the dose-effect relationship were analyzed by MTT.Caspase 3 protein activity was detected in the cells in 500,1000 and 2000 sub-groups.Mitochondrial transmembrane potential was detected by rhodamine 123 staining with the cells in 2000 sub-groups.Results MTT assay demonstrated that intense picosecond PEF significantly inhibited the proliferation of HeLa cells in dose-dependent manner.The survival rates of cells declined along with the increase in pulse number,and were 96.23%±0.76%,94.11%±2.42%,90.31%±1.77%,64.59%±1.59%,32.95%±0.73%,23.85%±2.38% and 100%,respectively,in 100,200,500,1000,1500,2000 sub-groups and control group(P < 0.01.The Caspase 3 protein activity was significantly enhanced by intense picosecond PEF,and the absorbancy indexes(A were 0.174±0.012,0.232±0.017,0.365±0.016 and 0.122±0.011,respectively,in 500,1000,2000 sub-groups and control group(P < 0.05.The mitochondrial transmembrane potential of HeLa cells was significantly inhibited by intense picosecond PEF,and the fluorescence intensity in 2000 sub-group(76.66±13.38 was much lower than that in control group(155.81±2.33,P < 0.05.Conclusion Intense picosecond PEF may significantly inhibit the growth of HeLa cells,and induce cell apoptosis via mitochondrial pathway.

  19. Automatic Detection of Electric Power Troubles (ADEPT)

    Science.gov (United States)

    Wang, Caroline; Zeanah, Hugh; Anderson, Audie; Patrick, Clint; Brady, Mike; Ford, Donnie

    1988-11-01

    Automatic Detection of Electric Power Troubles (A DEPT) is an expert system that integrates knowledge from three different suppliers to offer an advanced fault-detection system. It is designed for two modes of operation: real time fault isolation and simulated modeling. Real time fault isolation of components is accomplished on a power system breadboard through the Fault Isolation Expert System (FIES II) interface with a rule system developed in-house. Faults are quickly detected and displayed and the rules and chain of reasoning optionally provided on a laser printer. This system consists of a simulated space station power module using direct-current power supplies for solar arrays on three power buses. For tests of the system's ablilty to locate faults inserted via switches, loads are configured by an INTEL microcomputer and the Symbolics artificial intelligence development system. As these loads are resistive in nature, Ohm's Law is used as the basis for rules by which faults are located. The three-bus system can correct faults automatically where there is a surplus of power available on any of the three buses. Techniques developed and used can be applied readily to other control systems requiring rapid intelligent decisions. Simulated modeling, used for theoretical studies, is implemented using a modified version of Kennedy Space Center's KATE (Knowledge-Based Automatic Test Equipment), FIES II windowing, and an ADEPT knowledge base.

  20. Eradication of multidrug-resistant pseudomonas biofilm with pulsed electric fields.

    Science.gov (United States)

    Khan, Saiqa I; Blumrosen, Gaddi; Vecchio, Daniela; Golberg, Alexander; McCormack, Michael C; Yarmush, Martin L; Hamblin, Michael R; Austen, William G

    2016-03-01

    Biofilm formation is a significant problem, accounting for over eighty percent of microbial infections in the body. Biofilm eradication is problematic due to increased resistance to antibiotics and antimicrobials as compared to planktonic cells. The purpose of this study was to investigate the effect of Pulsed Electric Fields (PEF) on biofilm-infected mesh. Prolene mesh was infected with bioluminescent Pseudomonas aeruginosa and treated with PEF using a concentric electrode system to derive, in a single experiment, the critical electric field strength needed to kill bacteria. The effect of the electric field strength and the number of pulses (with a fixed pulse length duration and frequency) on bacterial eradication was investigated. For all experiments, biofilm formation and disruption were confirmed with bioluminescent imaging and Scanning Electron Microscopy (SEM). Computation and statistical methods were used to analyze treatment efficiency and to compare it to existing theoretical models. In all experiments 1500 V are applied through a central electrode, with pulse duration of 50 μs, and pulse delivery frequency of 2 Hz. We found that the critical electric field strength (Ecr) needed to eradicate 100-80% of bacteria in the treated area was 121 ± 14 V/mm when 300 pulses were applied, and 235 ± 6.1 V/mm when 150 pulses were applied. The area at which 100-80% of bacteria were eradicated was 50.5 ± 9.9 mm(2) for 300 pulses, and 13.4 ± 0.65 mm(2) for 150 pulses. 80% threshold eradication was not achieved with 100 pulses. The results indicate that increased efficacy of treatment is due to increased number of pulses delivered. In addition, we that showed the bacterial death rate as a function of the electrical field follows the statistical Weibull model for 150 and 300 pulses. We hypothesize that in the clinical setting, combining systemic antibacterial therapy with PEF will yield a synergistic effect leading to improved

  1. The Study for Shortening the Process Time at Soy Food Production by using the Pulsed Electric Field

    Science.gov (United States)

    Saito, Tsukasa; Jinushi, Makoto; Minamitani, Yasushi

    We investigated method to osmose water and seasoner to dried soybeans fast by pulsed electric field, in order to make soybeans a processed food fast. By applying the pulsed electric field to the dried soybeans in water, osmosis time of water to the soybean became approximately half. Then the emission of the discharge was observed on dried soybean. The color of coffee permeated more into the soybean treated than no-treated by the pulsed electric field.

  2. Influence Voltage Pulse Electrical Discharge In The Water at the Endurance Fatigue Of Carbon Steel

    OpenAIRE

    I.A. Vakulenko; A.G. Lisnyak

    2016-01-01

    Effect of pulses of electrical discharge in the water at the magnitude of the limited endurance under cyclic loading thermally hardened carbon steel was investigated. Observed increase stamina during cyclic loading a corresponding increase in the number of accumulated dislocations on the fracture surface. Using the equation of Cofino-Manson has revealed a decrease of strain loading cycle after treatment discharges. For field-cycle fatigue as a result of processing the voltage pulses carbon st...

  3. A novel application of pulsed electric field (PEF) processing for improving glutathione (GSH) antioxidant activity.

    Science.gov (United States)

    Wang, Jia; Wang, Ke; Wang, Ying; Lin, Songyi; Zhao, Ping; Jones, Gregory

    2014-10-15

    Glutathione (GSH) was treated by pulsed electric field (PEF) processing to investigate its effect on antioxidant activity. The antioxidant activity of GSH was evaluated using 2,2-diphenyl-1-picrylhydrazy (DPPH) radical inhibition. A Box-Behnken design (BBD) with three independent variables, which were concentration, electric field intensity and pulse frequency was used to establish the regression equation of second-order response surface. Optimal conditions were as follows: GSH concentration 8.86mg/mL, electric field intensity 9.74kV/cm and pulse frequency 2549.08Hz. The DPPH radical inhibition increased from 81.83% to 97.40%. Near-infrared spectroscopy (NIR) and mid-infrared spectroscopy (MIR) were used to analyse the change of structure and functional groups of GSH. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Effects on functional groups and zeta potential of SAP1pulsed electric field technology.

    Science.gov (United States)

    Liang, Rong; Li, Xuenan; Lin, Songyi; Wang, Jia

    2017-01-01

    SAP 1 pulsed electric field (PEF) technology. The effects of electric field intensity and pulse frequency on SAP 1 electric field intensity 15 kV cm -1 , pulse frequency 1600 Hz and flow velocity 2.93 mL min -1 ). Furthermore, the PEF-treated SAP 1 < MW < 3kDa under optimal conditions lacked the characteristic absorbance of N-H, C = C and the amide band and the zeta potential was reduced to -18.0 mV. Overall, the results of the present study suggest that the improvement of antioxidant activity of SAP 1 < MW < 3kDa is a result of the contribution of the functional groups and the change in zeta potential when treated with PEF. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  5. Electrical Tree Initiation and Growth in Silicone Rubber under Combined DC-Pulse Voltage

    Directory of Open Access Journals (Sweden)

    Tao Han

    2018-03-01

    Full Text Available Electrical tree is a serious threat to silicone rubber (SIR insulation and can even cause breakdown. Electrical trees under alternating current (AC and direct current (DC voltage have been widely researched. While there are pulses in high-voltage direct current (HVDC cables under operating conditions caused by lightning and operating overvoltage in the power system, little research has been reported about trees under combined DC-pulse voltage. Their inception and growth mechanism is still not clear. In this paper, electrical trees are studied under several types of combined DC-pulse voltage. The initiation and growth process was recorded by a digital microscope system. The experimental results indicate that the inception pulse voltage is different under each voltage type and is influenced by the combined DC. The initial tree has two structures, determined by the pulse polarity. With increased DC prestressing time, tree inception pulse voltage with the same polarity is clearly decreased. Moreover, a special initial bubble tree was observed after the prestressing DC.

  6. Synchronized and configurable source of electrical pulses for x-ray pump-probe experiments

    International Nuclear Information System (INIS)

    Strachan, J. P.; Chembrolu, V.; Yu, X. W.; Tyliszczak, T.; Acremann, Y.

    2007-01-01

    A method is described for the generation of software tunable patterns of nanosecond electrical pulses. The bipolar, high repetition rate (up to 250 MHz), fast rise time (<30 ps), square pulses are suitable for applications such as the excitation sequence in dynamic pump-probe experiments. Synchronization with the time structure of a synchrotron facility is possible as well as fine control of the relative delay in steps of 10 ps. The pulse generator described here is used to excite magnetic nanostructures with current pulses. Having an excitation system which can match the high repetition rate of a synchrotron allows for utilization of the full x-ray flux and is needed in experiments which require a large photon flux. The fast rise times allow for picosecond time resolution in pump-probe experiments. All pulse pattern parameters are configurable by software

  7. Time-resolved electrical measurements of a pulsed-dc methane discharge used in diamond-like carbon films production

    International Nuclear Information System (INIS)

    Corbella, C.; Polo, M.C.; Oncins, G.; Pascual, E.; Andujar, J.L.; Bertran, E.

    2005-01-01

    Amorphous hydrogenated carbon (a-C:H) thin films were obtained at room temperature via asymmetric bipolar pulsed-dc methane glow discharge. The power frequency values were varied from 100 to 200 kHz and the maximum amplitude voltage from -600 to -1400 V. Such films present diamond-like carbon (DLC) properties [J.L. Andujar, M. Vives, C. Corbella, E. Bertran, Diamond Relat. Mater. 12 (2003) 98]. The plasma, powered by a pulse frequency of 100 kHz, was electrically studied by a Langmuir probe. The next parameters were calculated within the pulse cycle from I-V measurements with 1 μs resolution: plasma and floating potentials, electron temperature, and electron and ion densities. The presence of a population of hot electrons (10 eV) was detected at high bias voltage region. The density of cold electrons grows one order of magnitude after each negative pulse, whereas the ion density suffers a prompt increase during each positive pulse. The surface topography of DLC films was scanned by atomic force microscopy (AFM). A smoothly varying friction coefficient (between 0.2 and 0.3) was measured by AFM in contact mode. X-ray reflectivity (XRR) analysis provided a wide characterization of the films, involving density, thickness and roughness. The C/H ratio, as directly obtained by elemental analysis (EA), shows an increase at higher bias voltages. All these features are discussed in terms of process parameters varied in film growth

  8. Tumour Cell Membrane Poration and Ablation by Pulsed Low-Intensity Electric Field with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Lijun Wang

    2015-03-01

    Full Text Available Electroporation is a physical method to increase permeabilization of cell membrane by electrical pulses. Carbon nanotubes (CNTs can potentially act like “lighting rods” or exhibit direct physical force on cell membrane under alternating electromagnetic fields thus reducing the required field strength. A cell poration/ablation system was built for exploring these effects of CNTs in which two-electrode sets were constructed and two perpendicular electric fields could be generated sequentially. By applying this system to breast cancer cells in the presence of multi-walled CNTs (MWCNTs, the effective pulse amplitude was reduced to 50 V/cm (main field/15 V/cm (alignment field at the optimized pulse frequency (5 Hz of 500 pulses. Under these conditions instant cell membrane permeabilization was increased to 38.62%, 2.77-fold higher than that without CNTs. Moreover, we also observed irreversible electroporation occurred under these conditions, such that only 39.23% of the cells were viable 24 h post treatment, in contrast to 87.01% cell viability without presence of CNTs. These results indicate that CNT-enhanced electroporation has the potential for tumour cell ablation by significantly lower electric fields than that in conventional electroporation therapy thus avoiding potential risks associated with the use of high intensity electric pulses.

  9. Measurement and analysis of the electric field radiation in pulsed power system of linear induction accelerator

    International Nuclear Information System (INIS)

    Cheng Qifeng; Ni Jianping; Meng Cui; Cheng Cheng; Liu Yinong; Li Jin

    2009-01-01

    The close of high voltage switch in pulsed power system of linear induction accelerator often radiates strong transient electric field, which may influence ambient sensitive electric equipment, signals and performance of other instruments, etc. By performing gridded measurement around the Marx generator, the general distribution law and basic characters of electric field radiation are summarized. The current signal of the discharge circuit is also measured, which demonstrates that the current and the radiated electric field both have a resonance frequency about 150 kHz, and contain much higher frequency components. (authors)

  10. Growth of pulsed electric field exposed Escherichia coli in relation to inactivation and environmental factors.

    Science.gov (United States)

    Aronsson, Kristina; Borch, Elisabeth; Stenlöf, Bo; Rönner, Ulf

    2004-05-15

    Pulsed electric fields (PEF) have been proven to inactivate microorganisms during nonthermal conditions and have the potential to replace thermal processing as a method for food preservation. However, there is a need to understand the recovery and growth of survivors and potentially injured microorganisms following PEF processing. The purpose of this investigation was to study the growth of Escherichia coli at 10 degrees C following exposure to electrical field strengths (15, 22.5 and 30 kV/cm) in relation to inactivation and the amount of potentially sublethally injured cells. One medium was used as both a treatment medium and an incubation medium, to study the influence of environmental factors on the inactivation and the growth of the surviving population. The pH (5.0, 6.0 and 7.0) and water activity (1.00, 0.985 and 0.97) of the medium was varied by adding HCl and glycerol, respectively. Growth was followed continuously by measuring the optical density. The time-to-detection (td) and the maximum specific growth rate (micromax) were calculated from these data. Results showed that the PEF process did not cause any obvious sublethal injury to the E. coli cells. The number of survivors was a consequence of the combination of electrical field strength and environmental factors, with pH being the most prominent. Interestingly, the micromax of subsequent growth was influenced by the applied electrical field strength during the process, with an increased micromax at more intense electrical field strengths. In addition, the micromax was also influenced by the pH and water activity. The td, which could theoretically be considered as an increase in shelf life, was found to depend on a complex correlation between electrical field strength, pH and water activity. That could be explained by the fact that the td is a combination of the number of survivors, the recovery of sublethal injured cells and the growth rate of the survivors. Copyright 2003 Elsevier B.V.

  11. Pulsed and streamer discharges in air above breakdown electric field

    NARCIS (Netherlands)

    A.B. Sun (Anbang); H.J. Teunissen (Jannis); U. M. Ebert (Ute)

    2013-01-01

    htmlabstractA 3D particle model is developed to investigate the streamer formation in electric fields above the breakdown threshold, in atmospheric air (1bar, 300 Kelvin). Adaptive particle management, adaptive mesh refinement and parallel computing techniques are used in the code. Photoionization

  12. Evaluations of electric field in laser-generated pulsed plasma

    Czech Academy of Sciences Publication Activity Database

    Torrisi, L.; Gammino, S.; Láska, Leoš; Krása, Josef; Rohlena, Karel; Wolowski, J.

    2006-01-01

    Roč. 56, Suppl. B (2006), B580-B585 ISSN 0011-4626. [Symposium on Plasma Physics and Technology /22./. Prague, 26.06.2006-29.06.2006] Institutional research plan: CEZ:AV0Z10100523 Keywords : electric field in plasma * debye length * plasma temperature * plasma density Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.568, year: 2006

  13. The effects of a picosecond pulsed electric field on angiogenesis in the cervical cancer xenograft models.

    Science.gov (United States)

    Wu, Limei; Yao, Chenguo; Xiong, Zhengai; Zhang, Ruizhe; Wang, Zhiliang; Wu, Yutong; Qin, Qin; Hua, Yuanyuan

    2016-04-01

    The application of picosecond pulsed electric field (psPEF) is a new biomedical engineering technique used in cancer therapy. However, its effects on cervical cancer angiogenesis are not clear. Therefore, the aim of the present study is to investigate the effects of psPEF on angiogenesis in cervical cancer xenograft models. Xenograft tumors were created by subcutaneously inoculating nude mice (athymic BALB/c nu/nu mice) with HeLa cells, then were placed closely between tweezer-type plate electrodes and subjected to psPEF with a gradually increased electric field intensity (0kV/cm, 50kV/cm, 60kV/cm, 70kV/cm). The direct effect on tumor tissue was observed by hematoxylin and eosin (H&E) staining and transmission electron microscopy (TEM). The changes of blood vessels and oxygen saturation (sO2) of tumors were monitored in vivo by photoacoustic tomography (PAT). The microvessel density (MVD), vascular endothelial growth factor (VEGF) and hypoxia-inducible transcription factors (HIF-1α and HIF-2α) were detected by immunohistochemical technique (IHC). Their protein expressions and gene transcription levels were evaluated using western blot (WB) and quantitative reverse transcription and polymerase chain reaction (RT-PCR). PsPEF induced obvious necrosis of cervical cancer tissue; with the increasing of electric field intensity, the MVD, vascular PA signal and sO2 values declined significantly. The protein expression and gene transcription levels of VEGF, HIF1α and HIF2α were significantly decreased at the same time. PsPEF exhibited dramatic anti-tumor and anti-angiogenesis effects in cervical cancer xenograft models by exerting direct effect on cancer cells and vascular endothelial cells and indirect effect on tumor angiogenesis-related factors. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. High impact ionization rate in silicon by sub-picosecond THz electric field pulses (Conference Presentation)

    DEFF Research Database (Denmark)

    Tarekegne, Abebe Tilahun; Iwaszczuk, Krzysztof; Hirori, Hideki

    2017-01-01

    Summary form only given. Metallic antenna arrays fabricated on high resistivity silicon are used to localize and enhance the incident THz field resulting in high electric field pulses with peak electric field strength reaching several MV/cm on the silicon surface near the antenna tips. In such high...... electric field strengths high density of carriers are generated in silicon through impact ionization process. The high density of generated carriers induces a change of refractive index in silicon. By measuring the change of reflectivity of tightly focused 800 nm light, the local density of free carriers...... near the antenna tips is measured. Using the NIR probing technique, we observed that the density of carriers increases by over 8 orders of magnitude in a time duration of approximately 500 fs with an incident THz pulse of peak electric field strength 700 kV/cm. This shows that a single impact...

  15. Improvements in detection system for pulse radiolysis facility

    CERN Document Server

    Rao, V N; Manimaran, P; Mishra, R K; Mohan, H; Mukherjee, T; Nadkarni, S A; Sapre, A V; Shinde, S J; Toley, M

    2002-01-01

    This report describes the improvements made in the detection system of the pulse radiolysis facility based on a 7 MeV Linear Electron Accelerator (LINAC) located in the Radiation Chemistry and Chemical Dynamics Division of Bhabha Atomic Research Centre. The facility was created in 1986 for kinetic studies of transient species whose absorption lies between 200 and 700 nm. The newly developed detection circuits consist of a silicon (Si) photodiode (PD) detector for the wavelength range 450-1100 nm and a germanium (Ge) photodiode detector for the wavelength range 900-1600 nm. With these photodiode-based detection set-up, kinetic experiments are now routinely carried out in the wavelength range 450-1600 nm. The performance of these circuits has been tested using standard chemical systems. The rise time has been found to be 150 ns. The photo-multiplier tube (PMT) bleeder circuit has been modified. A new DC back-off circuit has been built and installed in order to avoid droop at longer time scales. A steady baselin...

  16. Inactivation of Listeria innocua in liquid whole egg by pulsed electric fields and nisin.

    Science.gov (United States)

    Calderón-Miranda, M L; Barbosa-Cánovas, G V; Swanson, B G

    1999-10-01

    Consumer demand for fresh-like products with little or no degradation of nutritional and organoleptic properties has led to the study of new technologies in food preservation. Pulsed electric fields (PEF) is a nonthermal preservation method used to inactivate microorganisms mainly in liquid foods. Microorganisms in the presence of PEF suffer cell membrane damage. Nisin is a natural antimicrobial known to disrupt cell membrane integrity. Thus the combination of PEF and nisin represents a hurdle for the survival of Listeria innocua in liquid whole egg (LWE). L. innocua suspended in LWE was subjected to two different treatments: PEF and PEF followed by exposure to nisin. The selected frequency and pulse duration for PEF was 3.5 Hz and 2 micros, respectively. Electric field intensities of 30, 40 and 50 kV/cm were used. The number of pulses applied to the LWE was 10.6, 21.3 and 32. The highest extent of microbial inactivation with PEF was 3.5 log cycles (U) for an electric field intensity of 50 kV/cm and 32 pulses. Treatment of LWE by PEF was conducted at low temperatures, 36 degrees C being the highest. Exposure of L. innocua to nisin following the PEF treatment exhibited an additive effect on the inactivation of the microorganism. Moreover, a synergistic effect was observed as the electric field intensity, number of pulses and nisin concentration increased. L. innocua exposed to 10 IU nisin/ml after PEF exhibited a decrease in population of 4.1 U for an electric field intensity of 50 kV/cm and 32 pulses. Exposure of L. innocua to 100 IU nisin/ml following PEF resulted in 5.5 U for an electric field intensity of 50 kV/cm and 32 pulses. The model developed for the inactivation of L. innocua by PEF and followed by exposure to nisin proved to be accurate (p = 0.05) when used to model the inactivation of the microorganism by PEF in LWE with 1.2 or 37 IU nisin/ml. The presence of 37 IU nisin/ml in LWE during the PEF treatment for an electric field intensity of 50 kV/cm and

  17. Pulse Oximetry and Auscultation for Congenital Heart Disease Detection.

    Science.gov (United States)

    Hu, Xiao-Jing; Ma, Xiao-Jing; Zhao, Qu-Ming; Yan, Wei-Li; Ge, Xiao-Ling; Jia, Bing; Liu, Fang; Wu, Lin; Ye, Ming; Liang, Xue-Cun; Zhang, Jing; Gao, Yan; Zhai, Xiao-Wen; Huang, Guo-Ying

    2017-10-01

    Pulse oximetry (POX) has been confirmed as a specific screening modality for critical congenital heart disease (CCHD), with moderate sensitivity. However, POX is not able to detect most serious and critical cardiac lesions (major congenital heart disease [CHD]) without hypoxemia. In this study, we investigated the accuracy and feasibility of the addition of cardiac auscultation to POX as a screening method for asymptomatic major CHD. A multicenter prospective observational screening study was conducted at 15 hospitals in Shanghai between July 1, 2012, and December 31, 2014. Newborns with either an abnormal POX or cardiac auscultation were defined as screen positive. All screen-positive newborns underwent further echocardiography. False-negative results were identified by clinical follow-up, parents' feedback, and telephone review. We assessed the accuracy of POX plus cardiac auscultation for the detection of major CHD. CHD screening was completed in all 15 hospitals, with a screening rate of 94.0% to 99.8%. In total, 167 190 consecutive asymptomatic newborn infants were screened, of which 203 had major CHD (44 critical and 159 serious). The sensitivity of POX plus cardiac auscultation was 95.5% (95% confidence interval 84.9%-98.7%) for CCHD and 92.1% (95% confidence interval 87.7%-95.1%) for major CHD. The false-positive rate was 1.2% for detecting CCHD and 1.1% for detecting major CHD. In our current study, we show that using POX plus cardiac auscultation significantly improved the detection rate of major CHD in the early neonatal stage, with high sensitivity and a reasonable false-positive rate. It provides strong evidence and a reliable method for neonatal CHD screening. Copyright © 2017 by the American Academy of Pediatrics.

  18. Comparative evaluation of experimental and theoretical erosion resistance of materials upon electric pulse treatment

    International Nuclear Information System (INIS)

    Karpman, M.G.; Fetisov, G.P.; Bologov, D.V.

    1999-01-01

    Using the Palatnik criterion a comparative analysis is performed of the theoretical and experimental data on comparative electric erosion and erosion resistance of the electrodes and parts made of different materials upon their treatment using electric pulse technique. A reasonable qualitative agreement of the theoretical and experimental data indicates the possibility of using the Palatnik criterion to predict the serviceability of different pairs of the materials in conditions of electroerosion wear [ru

  19. Overvoltage effect on electrical discharge type in medium-conductivity water in inhomogeneous pulsed electric field

    Science.gov (United States)

    Panov, V. A.; Vasilyak, L. M.; Pecherkin, V. Ya; Vetchinin, S. P.; Son, E. E.

    2018-01-01

    The transition between thermal and streamer discharges has been observed experimentally in water solution with conductivity 100 μS/cm applying positive voltage pulses to pin-to-rod electrodes. The transition happens at five-fold pulse amplitude. Considering streamer propagation as an ionization wave helped to establish relation between the parameters governing transition from one to another discharge mechanism.

  20. Measured electric field intensities near electric cloud discharges detected by the Kennedy Space Center's Lightning Detection and Ranging System, LDAR

    Science.gov (United States)

    Poehler, H. A.

    1977-01-01

    For a summer thunderstorm, for which simultaneous, airborne electric field measurements and Lightning Detection and Ranging (LDAR) System data was available, measurements were coordinated to present a picture of the electric field intensity near cloud electrical discharges detected by the LDAR System. Radar precipitation echos from NOAA's 10 cm weather radar and measured airborne electric field intensities were superimposed on LDAR PPI plots to present a coordinated data picture of thunderstorm activity.

  1. Evidence that pulsed electric field treatment enhances the cell wall porosity of yeast cells.

    Science.gov (United States)

    Ganeva, Valentina; Galutzov, Bojidar; Teissie, Justin

    2014-02-01

    The application of rectangular electric pulses, with 0.1-2 ms duration and field intensity of 2.5-4.5 kV/cm, to yeast suspension mediates liberation of cytoplasmic proteins without cell lysis. The aim of this study was to evaluate the effect of pulsed electric field with similar parameters on cell wall porosity of different yeast species. We found that electrically treated cells become more susceptible to lyticase digestion. In dependence on the strain and the electrical conditions, cell lysis was obtained at 2-8 times lower enzyme concentration in comparison with control untreated cells. The increase of the maximal lysis rate was between two and nine times. Furthermore, when applied at low concentration (1 U/ml), the lyticase enhanced the rate of protein liberation from electropermeabilized cells without provoking cell lysis. Significant differences in the cell surface of control and electrically treated cells were revealed by scanning electron microscopy. Data presented in this study allow us to conclude that electric field pulses provoke not only plasma membrane permeabilization, but also changes in the cell wall structure, leading to increased wall porosity.

  2. Modification of Pulsed Electric Field Conditions Results in Distinct Activation Profiles of Platelet-Rich Plasma.

    Directory of Open Access Journals (Sweden)

    Andrew L Frelinger

    Full Text Available Activated autologous platelet-rich plasma (PRP used in therapeutic wound healing applications is poorly characterized and standardized. Using pulsed electric fields (PEF to activate platelets may reduce variability and eliminate complications associated with the use of bovine thrombin. We previously reported that exposing PRP to sub-microsecond duration, high electric field (SMHEF pulses generates a greater number of platelet-derived microparticles, increased expression of prothrombotic platelet surfaces, and differential release of growth factors compared to thrombin. Moreover, the platelet releasate produced by SMHEF pulses induced greater cell proliferation than plasma.To determine whether sub-microsecond duration, low electric field (SMLEF bipolar pulses results in differential activation of PRP compared to SMHEF, with respect to profiles of activation markers, growth factor release, and cell proliferation capacity.PRP activation by SMLEF bipolar pulses was compared to SMHEF pulses and bovine thrombin. PRP was prepared using the Harvest SmartPreP2 System from acid citrate dextrose anticoagulated healthy donor blood. PEF activation by either SMHEF or SMLEF pulses was performed using a standard electroporation cuvette preloaded with CaCl2 and a prototype instrument designed to take into account the electrical properties of PRP. Flow cytometry was used to assess platelet surface P-selectin expression, and annexin V binding. Platelet-derived growth factor (PDGF, vascular endothelial growth factor (VEGF, endothelial growth factor (EGF and platelet factor 4 (PF4, and were measured by ELISA. The ability of supernatants to stimulate proliferation of human epithelial cells in culture was also evaluated. Controls included vehicle-treated, unactivated PRP and PRP with 10 mM CaCl2 activated with 1 U/mL bovine thrombin.PRP activated with SMLEF bipolar pulses or thrombin had similar light scatter profiles, consistent with the presence of platelet

  3. Modification of Pulsed Electric Field Conditions Results in Distinct Activation Profiles of Platelet-Rich Plasma.

    Science.gov (United States)

    Frelinger, Andrew L; Gerrits, Anja J; Garner, Allen L; Torres, Andrew S; Caiafa, Antonio; Morton, Christine A; Berny-Lang, Michelle A; Carmichael, Sabrina L; Neculaes, V Bogdan; Michelson, Alan D

    2016-01-01

    Activated autologous platelet-rich plasma (PRP) used in therapeutic wound healing applications is poorly characterized and standardized. Using pulsed electric fields (PEF) to activate platelets may reduce variability and eliminate complications associated with the use of bovine thrombin. We previously reported that exposing PRP to sub-microsecond duration, high electric field (SMHEF) pulses generates a greater number of platelet-derived microparticles, increased expression of prothrombotic platelet surfaces, and differential release of growth factors compared to thrombin. Moreover, the platelet releasate produced by SMHEF pulses induced greater cell proliferation than plasma. To determine whether sub-microsecond duration, low electric field (SMLEF) bipolar pulses results in differential activation of PRP compared to SMHEF, with respect to profiles of activation markers, growth factor release, and cell proliferation capacity. PRP activation by SMLEF bipolar pulses was compared to SMHEF pulses and bovine thrombin. PRP was prepared using the Harvest SmartPreP2 System from acid citrate dextrose anticoagulated healthy donor blood. PEF activation by either SMHEF or SMLEF pulses was performed using a standard electroporation cuvette preloaded with CaCl2 and a prototype instrument designed to take into account the electrical properties of PRP. Flow cytometry was used to assess platelet surface P-selectin expression, and annexin V binding. Platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), endothelial growth factor (EGF) and platelet factor 4 (PF4), and were measured by ELISA. The ability of supernatants to stimulate proliferation of human epithelial cells in culture was also evaluated. Controls included vehicle-treated, unactivated PRP and PRP with 10 mM CaCl2 activated with 1 U/mL bovine thrombin. PRP activated with SMLEF bipolar pulses or thrombin had similar light scatter profiles, consistent with the presence of platelet

  4. Sodium current inhibition by nanosecond pulsed electric field (nsPEF)--fact or artifact?

    NARCIS (Netherlands)

    Verkerk, Arie O.; van Ginneken, Antoni C. G.; Wilders, Ronald

    2013-01-01

    In two recent publications in Bioelectromagnetics it has been demonstrated that the voltage-gated sodium current (I(Na)) is inhibited in response to a nanosecond pulsed electric field (nsPEF). At the same time, there was an increase in a non-inactivating "leak" current (I(leak)), which was

  5. Effect of Electric-current Pulses on Grain-structure Evolution in Cryogenically Rolled Copper

    Science.gov (United States)

    2014-11-01

    severely deformed dilute aluminium alloy . Acta Mater. 56, 1619 (2008). 4. T. Konkova, S. Mironov, A. Korznikov, and S.L. Semiatin: Microstructural response...phase transformation and variant selection by electric current pulses in a Cu-Zn alloy . J. Mater. Res. 29, 975 (2014). 13. I.Sh. Valeev and Z.G

  6. Pulsed Electric Field for protein release of the microalgae Chlorella vulgaris and Neochloris oleoabundans

    NARCIS (Netherlands)

    Lam, 't Gerard; Postma, P.R.; Fernandes, D.A.; Timmermans, R.A.H.; Vermuë, M.H.; Barbosa, M.J.; Eppink, M.H.; Wijffels, R.H.; Olivieri, G.

    2017-01-01

    Pulsed Electric Field (PEF) is currently discussed as promising technology for mild and scalable cell disintegration of microalgae. In this study Chlorella vulgaris and Neochloris oleoabundans have been subjected to batch and continuous PEF treatments under a wide range of operating conditions

  7. The separation of heavy ion tracks in nuclear emulsions by means of the pulsed electric field

    International Nuclear Information System (INIS)

    Akopova, A.B.; Magradze, N.V.; Melkumyan, L.V.; Prokhorenko, Y.P.

    1976-01-01

    The pulsed electric field (PEF) technique is developed for the separation of heavy ion tracks from the intense background caused by high energy electrons, protons and γ-radiation. The tracks of Ne, Cr, Ar-ions accelerated at the Dubna Nuclear Reactions Laboratory have been separated from the background, the voltage of the applied PEF being 10 5 V/cm. (orig.) [de

  8. Effect of pulsed electric field treatment on hot-boned muscles of different potential tenderness.

    Science.gov (United States)

    Suwandy, Via; Carne, Alan; van de Ven, Remy; Bekhit, Alaa El-Din A; Hopkins, David L

    2015-07-01

    In this study, the effect of pulsed electric field (PEF) treatment and ageing on the quality of beef M. longissimus lumborum (LL) and M. semimembranosus (SM) muscles was evaluated, including the tenderness, water loss and post-mortem proteolysis. Muscles were obtained from 12 steers (6 steers for each muscle), removed from the carcasses 4 hour postmortem and were treated with pulsed electric field within 2h. Six different pulsed electric field intensities (voltages of 5 and 10 kV × frequencies of 20, 50 and 90 Hz) plus a control were applied to each muscle to determine the optimum treatment conditions. Beef LL was found to get tougher with increasing treatment frequency whereas beef SM muscle was found to have up to 21.6% reduction in the shear force with pulsed electric field treatment. Post-mortem proteolysis showed an increase in both troponin and desmin degradation in beef LL treated with low intensity PEF treatment (20 Hz) compared to non-treated control samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. S. cerevisiae fermentation activity after moderate pulsed electric field pre-treatments.

    Science.gov (United States)

    Mattar, Jessy R; Turk, Mohammad F; Nonus, Maurice; Lebovka, Nikolai I; El Zakhem, Henri; Vorobiev, Eugene

    2015-06-01

    The batch fermentation process, inoculated by Pulsed Electric Field (PEF) treated wine yeasts (Saccharomyces cerevisiae Actiflore F33), was studied. PEF treatment was applied to the aqueous yeast suspensions ([Y] = 0.012 g/L) at the electric field strengths of E = 100 and 6000 V/cm using the same treatment protocol (number of pulses n = 1000, pulse duration ti = 100 μs, and pulse repetition time Δt = 100 ms). Electrical conductivity was increasing during and after the PEF treatment, which reflected cell electroporation. Then, fermentation was run for 150 h in an incubator (30 °C) with synchronic agitation. Electro-stimulation was revealing itself by the improvement of fermentation characteristics, and thus increased yeast metabolism. At the end of the lag phase (t = 40 h), fructose consumption in samples with electrically activated inoculum exceeded that of the control samples by ≈ 2.33 times for E = 100 V/cm and by ≈ 3.98 for E = 6000 V/cm. At the end of the log phase (120 h of fermentation), ≈ 30% mass reduction was reached in samples with PEF-treated inocula (E = 6000 V/cm), whereas the same mass reduction of the control sample required approximately 20 extra hours of fermentation. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Effects on DPPH inhibition of egg-white protein polypeptides treated by pulsed electric field technology.

    Science.gov (United States)

    Wang, Ke; Wang, Jia; Liu, Bolong; Lin, Songyi; Zhao, Ping; Liu, Jingbo; Jones, Gregory; Huang, Hsiang-Chi

    2013-05-01

    Egg-white protein polypeptides are potentially used as a functional ingredient in food products. In this study, the effects on DPPH inhibition of egg-white protein polypeptides ranging from 10 to 30 kDa treated by pulsed electric field (PEF) technology were investigated. 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) inhibition (%) was used to evaluate the antioxidant activity of polypeptides. In order to develop and optimize a pulsed electric field (PEF) mathematical model for improving the antioxidant activity, we have investigated three variables, including concentration (6, 8 and 10 mg mL(-1)), electric field intensity (10, 20 and 30 kV cm(-1)) and pulse frequency (2000, 2350 and 2700 Hz) and subsequently optimized them by response surface methodology (RSM). The concentration (8 mg mL(-1)), electric field intensity (10 kV cm(-1)) and pulse frequency (2000 Hz) were found to be the optimal conditions under which the DPPH inhibition increased 28.44%, compared to the sample without PEF treatment. Both near-infrared spectroscopy (NIR) and mid-infrared spectroscopy (MIR) were used to analyze the change of functional groups. The results showed that PEF technology could improve the antioxidant activity of antioxidant polypeptides from egg-white protein under the optimized conditions. © 2012 Society of Chemical Industry.

  11. Conductive plastic film electrodes for Pulsed Electric Field (PEF) treatment : A proof of principle

    NARCIS (Netherlands)

    Roodenburg, B.; Haan, S.W.H. de; Boxtel, L.B.J. van; Hatt, V.; Wouters, P.C.; Coronel, P.; Ferreira, J.A.

    2010-01-01

    Nowadays Pulsed Electric Field (PEF) treatment of food needs to be performed prior to packaging, either hygienic or aseptic packaging is necessary. New techniques for PEF treatment after packaging can be considered when plastic conductive (film) electrodes can be integrated within the package, so

  12. Effect of pulsed electric field on the germination of barley seeds

    DEFF Research Database (Denmark)

    Dymek, Katarzyna; Dejmek, Petr; Panarese, Valentina

    2012-01-01

    This study explores metabolic responses of germinating barley seeds upon the application of pulsed electric fields (PEF). Malting barley seeds were steeped in aerated water for 24 h and PEF-treated at varying voltages (0 (control), 110, 160, 240, 320, 400 and 480 V). The seeds were then allowed...

  13. An electrical pulse hydride injector (EPHI) for reactor fueling and tritium handling applications

    International Nuclear Information System (INIS)

    Azizov, E.A.; Kareev, Yu.A.; Savotkin, A.N.; Frunze, V.V.; Penzhorn, R.D.; Glugla, M.

    1995-01-01

    An electrical pulse hydride injector (EPHI) has been developed for reactor fuelling as well as for handling of hydrogen isotopes in facilities operating with tritium. Salient features of the EPHI are the accuracy with which the fuelling rate can be controlled and the avoidance of a pressurized ballast. The generator is simple and allows for safe operation with tritium. (orig.)

  14. Cost analysis of commercial pasteurization of orange juice by pulsed electric fields

    Science.gov (United States)

    The cost of pulsed electric field (PEF) pasteurization of orange juice was estimated. The cost analysis was based on processing conditions that met the US FDA (5 log reduction) requirement for fruit juice pasteurization and that achieved a 2 month microbial shelf-life. PEF-treated samples processed ...

  15. Higher-order power harmonics of pulsed electrical stimulation modulates corticospinal contribution of peripheral nerve stimulation.

    Science.gov (United States)

    Chen, Chiun-Fan; Bikson, Marom; Chou, Li-Wei; Shan, Chunlei; Khadka, Niranjan; Chen, Wen-Shiang; Fregni, Felipe

    2017-03-03

    It is well established that electrical-stimulation frequency is crucial to determining the scale of induced neuromodulation, particularly when attempting to modulate corticospinal excitability. However, the modulatory effects of stimulation frequency are not only determined by its absolute value but also by other parameters such as power at harmonics. The stimulus pulse shape further influences parameters such as excitation threshold and fiber selectivity. The explicit role of the power in these harmonics in determining the outcome of stimulation has not previously been analyzed. In this study, we adopted an animal model of peripheral electrical stimulation that includes an amplitude-adapted pulse train which induces force enhancements with a corticospinal contribution. We report that the electrical-stimulation-induced force enhancements were correlated with the amplitude of stimulation power harmonics during the amplitude-adapted pulse train. In an exploratory analysis, different levels of correlation were observed between force enhancement and power harmonics of 20-80 Hz (r = 0.4247, p = 0.0243), 100-180 Hz (r = 0.5894, p = 0.0001), 200-280 Hz (r = 0.7002, p harmonics. This is a pilot, but important first demonstration that power at high order harmonics in the frequency spectrum of electrical stimulation pulses may contribute to neuromodulation, thus warrant explicit attention in therapy design and analysis.

  16. A Pulsed Electric Field (PEF) bench static system to study bacteria inactivation

    International Nuclear Information System (INIS)

    Cortese, Pietro; Dellacasa, Giuseppe; Gemme, Roberto; Bonetta, Sara; Bonetta, Silvia; Carraro, Elisabetta; Motta, Francesca; Paganoni, Marco; Pizzichemi, Marco

    2011-01-01

    Pulsed Electric Fields (PEF) technology is a promising non-thermal processing method for inactivation of microorganisms. A small PEF bench system able to treat a 0.4 ml static liquid volume has been built and tested at the laboratories of the Universita del Piemonte Orientale in Alessandria, Italy. The technique used to produce the required fields consists of charging high voltage cables of various lengths and subsequently discharge them on a cylindrical cell. The pulse intensity can be adjusted to reach a maximum electric field in the cell of about 35 kV/cm and the pulse frequency can reach 10 Hz. We describe the PEF system in some detail and, as a benchmark of its performances, we report preliminary results obtained on Escherichia coli (ATCC 25922) at 10 9 Cfu/ml concentration suspended in a McIlvaine buffer (pH 7.2).

  17. The neuronal response to electrical constant-amplitude pulse train stimulation: additive Gaussian noise.

    Science.gov (United States)

    Matsuoka, A J; Abbas, P J; Rubinstein, J T; Miller, C A

    2000-11-01

    Experimental results from humans and animals show that electrically evoked compound action potential (EAP) responses to constant-amplitude pulse train stimulation can demonstrate an alternating pattern, due to the combined effects of highly synchronized responses to electrical stimulation and refractory effects (Wilson et al., 1994). One way to improve signal representation is to reduce the level of across-fiber synchrony and hence, the level of the amplitude alternation. To accomplish this goal, we have examined EAP responses in the presence of Gaussian noise added to the pulse train stimulus. Addition of Gaussian noise at a level approximately -30 dB relative to EAP threshold to the pulse trains decreased the amount of alternation, indicating that stochastic resonance may be induced in the auditory nerve. The use of some type of conditioning stimulus such as Gaussian noise may provide a more 'normal' neural response pattern.

  18. Red cherries (Prunus avium var. Stella) processed by pulsed electric field - Physical, chemical and microbiological analyses.

    Science.gov (United States)

    Sotelo, Kristine A G; Hamid, Nazimah; Oey, Indrawati; Pook, Chris; Gutierrez-Maddox, Noemi; Ma, Qianli; Ying Leong, Sze; Lu, Jun

    2018-02-01

    This study examined, for the first time, the effect of mild or moderate intensity pulsed electric field (PEF) processing on cherries, in particular changes in physicochemical properties, release of anthocyanins and polyphenols, and the potential growth of lactic acid bacteria. Cherry samples were treated at a constant pulse frequency of 100Hz and a constant pulse width of 20μs with different electric field strengths between 0.3 and 2.5kV/cm. Titratable acidity and total soluble solids values of most PEF samples stored for 24h significantly decreased compared to other samples. Stored samples also had increased cyanidin glucoside content. However, concentration of rutin, 4-hydroxybenzoic acid and isorhamnetin rutinoside significantly decreased in samples stored for 24h. In conclusion, sweet cherries were only influenced by storage after PEF processing. PEF processing did not affect the growth of probiotic bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Inactivation of microorganisms within collagen gel biomatrices using pulsed electric field treatment.

    Science.gov (United States)

    Griffiths, Sarah; Maclean, Michelle; Anderson, John G; MacGregor, Scott J; Grant, M Helen

    2012-02-01

    Pulsed electric field (PEF) treatment was examined as a potential decontamination method for tissue engineering biomatrices by determining the susceptibility of a range of microorganisms whilst within a collagen gel. High intensity pulsed electric fields were applied to collagen gel biomatrices containing either Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Candida albicans, Saccharomyces cerevisiae or the spores of Aspergillus niger. The results established varying degrees of microbial PEF susceptibility. When high initial cell densities (10(6)-10(7) CFU ml(-1)) were PEF treated with 100 pulses at 45 kV cm(-1), the greatest log reduction was achieved with S. cerevisiae (~6.5 log(10) CFU ml(-1)) and the lowest reduction achieved with S. epidermidis (~0.5 log(10) CFU ml(-1)). The results demonstrate that inactivation is influenced by the intrinsic properties of the microorganism treated. Further investigations are required to optimise the microbial inactivation kinetics associated with PEF treatment of collagen gel biomatrices.

  20. Electric field measurements in a nanosecond pulse discharge by picosecond CARS/4-wave mixing

    Science.gov (United States)

    Goldberg, Ben; Shkurenkov, Ivan; Adamovich, Igor; Lempert, Walter

    2014-10-01

    Time-resolved electric field measurements in hydrogen by picosecond CARS/4-wave mixing are presented. Measurements are carried out in a high voltage nanosecond pulse discharge in hydrogen in plane-to-plane geometry, at pressures of up to several hundred Torr, and with a time resolution of 0.2 ns. Absolute calibration of the diagnostics is done using a sub-breakdown high voltage pulse of 12 kV/cm. A diffuse discharge is obtained by applying a peak high voltage pulse of 40 kV/cm between the electrodes. It is found that breakdown occurs at a lower field, 15--20 kV/cm, after which the field in the plasma is reduced rapidly due to plasma self shielding The experimental results are compared with kinetic modeling calculations, showing good agreement between the measured and the predicted electric field.

  1. Thermal pulse measurements of space charge distributions under an applied electric field in thin films

    International Nuclear Information System (INIS)

    Zheng, Feihu; An, Zhenlian; Zhang, Yewen; Liu, Chuandong; Lin, Chen; Lei, Qingquan

    2013-01-01

    The thermal pulse method is a powerful method to measure space charge and polarization distributions in thin dielectric films, but a complicated calibration procedure is necessary to obtain the real distribution. In addition, charge dynamic behaviour under an applied electric field cannot be observed by the classical thermal pulse method. In this work, an improved thermal pulse measuring system with a supplemental circuit for applying high voltage is proposed to realize the mapping of charge distribution in thin dielectric films under an applied field. The influence of the modified measuring system on the amplitude and phase of the thermal pulse response current are evaluated. Based on the new measuring system, an easy calibration approach is presented with some practical examples. The newly developed system can observe space charge evolution under an applied field, which would be very helpful in understanding space charge behaviour in thin films. (paper)

  2. Pulsed Operation of a Compact Fusion Neutron Source Using a High-Voltage Pulse Generator Developed for Landmine Detection

    International Nuclear Information System (INIS)

    Yamauchi, Kunihito; Watanabe, Masato; Okino, Akitoshi; Kohno, Toshiyuki; Hotta, Eiki; Yuura, Morimasa

    2005-01-01

    Preliminary experimental results of pulsed neutron source based on a discharge-type beam fusion called Inertial Electrostatic Confinement Fusion (IECF) for landmine detection are presented. In Japan, a research and development project for constructing an advanced anti-personnel landmine detection system by using IECF, which is effective not only for metal landmines but also for plastic ones, is now in progress. This project consists of some R and D topics, and one of them is R and D of a high-voltage pulse generator system specialized for landmine detection, which can be used in the severe environment such as that in the field in Afghanistan. Thus a prototype of the system for landmine detection was designed and fabricated in consideration of compactness, lightness, cooling performance, dustproof and robustness. By using this prototype pulse generator system, a conventional IECF device was operated as a preliminary experiment. As a result, it was confirmed that the suggested pulse generator system is suitable for landmine detection system, and the results follow the empirical law obtained by the previous experiments. The maximum neutron production rate of 2.0x10 8 n/s was obtained at a pulsed discharge of -51 kV, 7.3 A

  3. Reduction of protease activity in milk by continuous flow high-intensity pulsed electric field treatments.

    Science.gov (United States)

    Bendicho, S; Barbosa-Cánovas, G V; Martín, O

    2003-03-01

    High-intensity pulsed electric field (HIPEF) is a non-thermal food processing technology that is currently being investigated to inactivate microorganisms and certain enzymes, involving a limited increase of food temperature. Promising results have been obtained on the inactivation of microbial enzymes in milk when suspended in simulated milk ultrafiltrate. The aim of this study was to evaluate the effectiveness of continuous HIPEF equipment on inactivating a protease from Bacillus subtilis inoculated in milk. Samples were subjected to HIPEF treatments of up to 866 micros of squared wave pulses at field strengths from 19.7 to 35.5 kV/cm, using a treatment chamber that consisted of eight colinear chambers connected in series. Moreover, the effects of different parameters such as pulse width (4 and 7 micros), pulse repetition rates (67, 89, and 111 Hz), and milk composition (skim and whole milk) were tested. Protease activity decreased with increased treatment time or field strength and pulse repetition rate. Regarding pulse width, no differences were observed between 4 and 7 micros pulses when total treatment time was considered. On the other hand, it was observed that milk composition affected the results since higher inactivation levels were reached in skim than in whole milk. The maximum inactivation (81%) was attained in skim milk after an 866-micros treatment at 35.5 kV/cm and 111 Hz.

  4. Photoinduced electric currents in ring-shaped molecules by circularly polarized laser pulses

    International Nuclear Information System (INIS)

    Nobusada, Katsuyuki; Yabana, Kazuhiro

    2007-01-01

    We have theoretically demonstrated that circularly polarized laser pulses induce electric currents and magnetic moments in ring-shaped molecules Na 10 and benzene. The time-dependent adiabatic local density approximation is employed for this purpose, solving the time-dependent Kohn-Sham equation in real space and real time. It has been found that the electric currents are induced efficiently and persist continuously even after the laser pulses were switched off provided the frequency of the applied laser pulse is in tune with the excitation energy of the electronic excited state with the dipole strength for each molecular system. The electric currents are definitely revealed to be a second-order nonlinear optical response to the magnitude of the electric field. The magnetic dipole moments inevitably accompany the ring currents, so that the molecules are magnetized. The production of the electric currents and the magnetic moments in the present procedure is found to be much more efficient than that utilizing static magnetic fields

  5. Strategies, Protections and Mitigations for Electric Grid from Electromagnetic Pulse Effects

    Energy Technology Data Exchange (ETDEWEB)

    Foster, Rita Ann [Idaho National Lab. (INL), Idaho Falls, ID (United States); Frickey, Steven Jay [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-01-01

    The mission of DOE’s Office of Electricity Delivery and Energy Reliability (OE) is to lead national efforts to modernize the electricity delivery system, enhance the security and reliability of America’s energy infrastructure and facilitate recovery from disruptions to the energy supply. One of the threats OE is concerned about is a high-altitude electro-magnetic pulse (HEMP) from a nuclear explosion and eletro-magnetic pulse (EMP) or E1 pulse can be generated by EMP weapons. DOE-OE provides federal leadership and technical guidance in addressing electric grid issues. The Idaho National Laboratory (INL) was chosen to conduct the EMP study for DOE-OE due to its capabilities and experience in setting up EMP experiments on the electric grid and conducting vulnerability assessments and developing innovative technology to increase infrastructure resiliency. This report identifies known impacts to EMP threats, known mitigations and effectiveness of mitigations, potential cost of mitigation, areas for government and private partnerships in protecting the electric grid to EMP, and identifying gaps in our knowledge and protection strategies.

  6. High-efficiency gene transfer into skeletal muscle mediated by electric pulses

    DEFF Research Database (Denmark)

    Mir, L M; Bureau, M F; Gehl, J

    1999-01-01

    Gene delivery to skeletal muscle is a promising strategy for the treatment of muscle disorders and for the systemic secretion of therapeutic proteins. However, present DNA delivery technologies have to be improved with regard to both the level of expression and interindividual variability. We...... report very efficient plasmid DNA transfer in muscle fibers by using square-wave electric pulses of low field strength (less than 300 V/cm) and of long duration (more than 1 ms). Contrary to the electropermeabilization-induced uptake of small molecules into muscle fibers, plasmid DNA has to be present...... in the tissue during the electric pulses, suggesting a direct effect of the electric field on DNA during electrotransfer. This i.m. electrotransfer method increases reporter and therapeutic gene expression by several orders of magnitude in various muscles in mouse, rat, rabbit, and monkey. Moreover, i...

  7. Enhancing Food Processing by Pulsed and High Voltage Electric Fields: Principles and Applications.

    Science.gov (United States)

    Wang, Qijun; Li, Yifei; Sun, Da-Wen; Zhu, Zhiwei

    2018-02-02

    Improvements in living standards result in a growing demand for food with high quality attributes including freshness, nutrition and safety. However, current industrial processing methods rely on traditional thermal and chemical methods, such as sterilization and solvent extraction, which could induce negative effects on food quality and safety. The electric fields (EFs) involving pulsed electric fields (PEFs) and high voltage electric fields (HVEFs) have been studied and developed for assisting and enhancing various food processes. In this review, the principles and applications of pulsed and high voltage electric fields are described in details for a range of food processes, including microbial inactivation, component extraction, and winemaking, thawing and drying, freezing and enzymatic inactivation. Moreover, the advantages and limitations of electric field related technologies are discussed to foresee future developments in the food industry. This review demonstrates that electric field technology has a great potential to enhance food processing by supplementing or replacing the conventional methods employed in different food manufacturing processes. Successful industrial applications of electric field treatments have been achieved in some areas such as microbial inactivation and extraction. However, investigations of HVEFs are still in an early stage and translating the technology into industrial applications need further research efforts.

  8. Aggregation of egg white proteins with pulsed electric fields and thermal processes.

    Science.gov (United States)

    Wu, Li; Zhao, Wei; Yang, Ruijin; Yan, Wenxu; Sun, Qianyan

    2016-08-01

    Pulsed electric field (PEF) processing is progressing towards application for liquid egg to ensure microbial safety. However, it usually causes protein aggregation, and the mechanism is still unclear. In this study, egg white protein was applied to investigate the changes in protein structure and mechanism of aggregates formation and a comparison was made with thermal treatment. Soluble protein content decreased with the increase of turbidity after both treatments. Fluorescence intensity and free sulfhydryl content were increased after being treated at 70 °C for 4 min. Less-remarkable changes of hydrophobicity were observed after PEF treatments (30 kV cm(-1) , 800 µs). Soluble and insoluble aggregates were observed by thermal treatment, and disulfide bonds were the main binding forces. The main components of insoluble aggregates formed by thermal treatment were ovotransferrin (30.58%), lysozyme (18.47%) and ovalbumin (14.20%). While only insoluble aggregates were detected during PEF processes, which consists of ovotransferrin (11.86%), lysozyme (21.11%) and ovalbumin (31.07%). Electrostatic interaction played a very important role in the aggregates formation. PEF had a minor impact on the structure of egg white protein. PEF had insignificant influence on heat-sensitive protein, indicating that PEF has potential in processing food with high biological activity and heat sensitive properties. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  9. Detection of UV Pulse from Insulators and Application in Estimating the Conditions of Insulators

    Science.gov (United States)

    Wang, Jingang; Chong, Junlong; Yang, Jie

    2014-10-01

    Solar radiation in the band of 240-280 nm is absorbed by the ozone layer in the atmosphere, and corona discharges from high-voltage apparatus emit in air mainly in the 230-405 nm range of ultraviolet (UV), so the band of 240-280 nm is called UV Solar Blind Band. When the insulators in a string deteriorate or are contaminated, the voltage distribution along the string will change, which causes the electric fields in the vicinity of insulators change and corona discharge intensifies. An UV pulse detection method to check the conditions of insulators is presented based on detecting the UV pulse among the corona discharge, then it can be confirmed that whether there exist faulty insulators and whether the surface contamination of insulators is severe for the safe operation of power systems. An UV-I Insulator Detector has been developed, and both laboratory tests and field tests have been carried out which demonstrates the practical viability of UV-I Insulator Detector for online monitoring.

  10. Pulse electrical discharges in water and their applications

    International Nuclear Information System (INIS)

    Sunka, Pavel

    2001-01-01

    Partial electrical discharges in a water solution as a function of conductivity have been studied experimentally. Using needle-plate electrodes it has been demonstrated that the discharge evolves in two phases. During the first streamer-like phase, the discharge propagated with a velocity of 10 6 cm/s, while during the second arc-like phase the length of the discharge remained almost constant although the current still increased. Higher solution conductivity resulted in the generation of shorter channels, in larger discharge current, and in a higher plasma electron density. Degradation of phenol by the discharge has also been demonstrated. A special metallic electrode covered by a thin layer of porous ceramic has been developed and used for generation of a multichannel discharge. At comparable solution conductivity the ceramic-coated electrode produced plasma with very similar parameters as the needle-plate electrode configuration. Generation of strong focused shock waves by the multichannel discharge in a highly conductive solution has also been demonstrated

  11. Exploring the Effects of Pulsed Electric Field Processing Parameters on Polyacetylene Extraction from Carrot Slices

    Directory of Open Access Journals (Sweden)

    Ingrid Aguiló-Aguayo

    2015-03-01

    Full Text Available The effects of various pulsed electric field (PEF parameters on the extraction of polyacetylenes from carrot slices were investigated. Optimised conditions with regard to electric field strength (1–4 kV/cm, number of pulses (100–1500, pulse frequency (10–200 Hz and pulse width (10–30 μs were identified using response surface methodology (RSM to maximise the extraction of falcarinol (FaOH, falcarindiol (FaDOH and falcarindiol-3-acetate (FaDOAc from carrot slices. Data obtained from RSM and experiments fitted significantly (p < 0.0001 the proposed second-order response functions with high regression coefficients (R2 ranging from 0.82 to 0.75. Maximal FaOH (188%, FaDOH (164.9% and FaDOAc (166.8% levels relative to untreated samples were obtained from carrot slices after applying PEF treatments at 4 kV/cm with 100 number of pulses of 10 μs at 10 Hz. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values with low average mean deviations (E% ranging from 0.68% to 3.58%.

  12. Giant lipid vesicles under electric field pulses assessed by non invasive imaging.

    Science.gov (United States)

    Mauroy, Chloé; Portet, Thomas; Winterhalder, Martin; Bellard, Elisabeth; Blache, Marie-Claire; Teissié, Justin; Zumbusch, Andreas; Rols, Marie-Pierre

    2012-10-01

    We present experimental results regarding the effects of electric pulses on giant unilamellar vesicles (GUVs). We have used phase contrast and coherent anti-Stokes Raman scattering (CARS) microscopy as relevant optical approaches to gain insight into membrane changes under electropermeabilization. No addition of exogenous molecules (lipid analogue, fluorescent dye) was needed. Therefore, experiments were performed on pure lipid systems avoiding possible artefacts linked to their use. Structural membrane changes were assessed by loss of contrast inside the GUVs due to sucrose and glucose mixing. Our observations, performed at the single vesicle level, indicate these changes are under the control of the number of pulses and field intensity. Larger number of pulses enhances membrane alterations. A threshold value of the field intensity must be applied to allow exchange of molecules between GUVs and the external medium. This threshold depends on the size of the vesicles, the larger GUVs being affected at lower electric field strengths than the smaller ones. Our experimental data are well described by a simple model in which molecule entry is driven by direct exchange. The CARS microscopic study of the effect of pulse duration confirms that pulses, in the ms time range, induce loss of lipids and membrane deformations facing the electrodes. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Photodetachment of H- by a short laser pulse in crossed static electric and magnetic fields

    International Nuclear Information System (INIS)

    Peng Liangyou; Wang Qiaoling; Starace, Anthony F.

    2006-01-01

    We present a detailed quantum mechanical treatment of the photodetachment of H - by a short laser pulse in the presence of crossed static electric and magnetic fields. An exact analytic formula is presented for the final state electron wave function (describing an electron in both static electric and magnetic fields and a short laser pulse of arbitrary intensity). In the limit of a weak laser pulse, final state electron wave packet motion is examined and related to the closed classical electron orbits in crossed static fields predicted by Peters and Delos [Phys. Rev. A 47, 3020 (1993)]. Owing to these closed orbit trajectories, we show that the detachment probability can be modulated, depending on the time delay between two laser pulses and their relative phase, thereby providing a means to partially control the photodetachment process. In the limit of a long, weak pulse (i.e., a monochromatic radiation field) our results reduce to those of others; however, for this case we analyze the photodetachment cross section numerically over a much larger range of electron kinetic energy (i.e., up to 500 cm -1 ) than in previous studies and relate the detailed structures both analytically and numerically to the above-mentioned, closed classical periodic orbits

  14. Measurement of electroosmotic and electrophoretic velocities using pulsed and sinusoidal electric fields.

    Science.gov (United States)

    Sadek, Samir H; Pimenta, Francisco; Pinho, Fernando T; Alves, Manuel A

    2017-04-01

    In this work, we explore two methods to simultaneously measure the electroosmotic mobility in microchannels and the electrophoretic mobility of micron-sized tracer particles. The first method is based on imposing a pulsed electric field, which allows to isolate electrophoresis and electroosmosis at the startup and shutdown of the pulse, respectively. In the second method, a sinusoidal electric field is generated and the mobilities are found by minimizing the difference between the measured velocity of tracer particles and the velocity computed from an analytical expression. Both methods produced consistent results using polydimethylsiloxane microchannels and polystyrene micro-particles, provided that the temporal resolution of the particle tracking velocimetry technique used to compute the velocity of the tracer particles is fast enough to resolve the diffusion time-scale based on the characteristic channel length scale. Additionally, we present results with the pulse method for viscoelastic fluids, which show a more complex transient response with significant velocity overshoots and undershoots after the start and the end of the applied electric pulse, respectively. © 2016 The Authors. Electrophoresis published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Is pulsed electric field still effective for RNA separation in capillary electrophoresis?

    Science.gov (United States)

    Li, Zhenqing; Dou, Xiaoming; Ni, Yi; Chen, Qinmiao; Cheng, Shuyi; Yamaguchi, Yoshinori

    2012-03-16

    Pulsed field capillary electrophoresis (PFCE) is a predominant technique to cope with difficulties in resolving large DNA strands, yet it is still unclear whether pulsed electric field is effective for the separation of higher mass RNA. In this paper we focused on the role of pulsed electric field in large RNA fragments analysis by comparing RNA separation performance in PFCE with that in constant field CE. Separation performance in terms of migration mobility, plate numbers, resolution, and selectivity has been tested for the analysis of RNA from 0.1 to 10.0 kilo nucleotide (knt) under different electrophoretic conditions. Denaturation, important to obtain uniform and identifiable peaks, was accomplished by heating the sample in 4.0M urea prior to analysis and the presence of 4.0M urea in the electrophoresis buffer. Results demonstrate that unlike DNA in PFCE, the pulsed electric field mainly affects the separation performance of RNA between 0.4 and 2.0 knt. The migration mobility of long RNA fragments is not a strong function of modulation depth and pulsed frequency. Moreover, the logarithm of RNA mobility is almost inversely proportional to the logarithm of molecule size up to 6.0 knt with correlation coefficient higher than 0.99 in all the polymer concentrations measured here. Resonance frequency of RNA in PFCE was also observed. While these initial experiments show no distinct advantages of using PFCE for RNA separation, they do take further step toward characterizing the migration behavior of RNA under pulsed field conditions. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Detection of time of arrival of ultrasonic pulses

    International Nuclear Information System (INIS)

    Latino, Carl D; Andersen, Niels Lervad; Voss, Frands

    2006-01-01

    Applications exist that employ transit-time measurements to determine distances to scattering objects. These include blood-flow measurements, fluid-level detection, nondestructive testing of materials, image processing of geometrical bodies etc. Many of these require extreme accuracy in measuring transit time through a medium. The system typically consists of a transmitter, a medium and a receiver. The signal sent must operate within the limitations imposed by this overall system. Under ideal conditions a finite duration pulse consisting of a sinusoidal signal is sent and received. If the transmitted signal contains an integer number of complete cycles of a single frequency, performing a correlation between transmitted and received signals can accurately recover the transit time information. The method has difficulties especially in the presence of noise. The problem is compounded if the desired accuracy is a small fraction of a single sinusoid period. Noise could cause the correlation results to be off by a complete cycle. For a one MHz signal, one cycle error corresponds to a one microsecond error. For applications requiring nanosecond accuracy, this is not acceptable. Varying the frequency content of the signal reduces the error but requires that the transmitter, receiver and medium all have a broader band spectrum. The improvements we propose here work within a narrow band while enhancing the chance of recovering the signal accurately

  17. Parametric performance predictions for high-power pulsed electric CO lasers

    International Nuclear Information System (INIS)

    Center, R.E.; Caledonia, G.E.

    1975-01-01

    A kinetic model of the pulsed electrical CO laser is used to survey the time-dependent laser performance on parameters such as gas mixture, initial translational temperature, and discharge pulse length for both multiline and selected-line operation. Predictions are presented for the total output efficiency, spectral distributions of the stimulated transitions, energy partitioning in the vibrational and translational modes, and the translational temperature history in CO-N 2 mixtures. A brief description of the kinetic model is included. Simple scaling relationships are presented which can be used to scale the results to other densities in the pressure-broadened regime

  18. Effect of a pulsed power supply on the spectral and electrical characteristics of HID lamps

    International Nuclear Information System (INIS)

    Chammam, Abdeljelil; Elloumi, Hatem; Mrabet, Brahim; Charrada, Kamel; Stambouli, Mongi; Damelincourt, Jean Jacques

    2005-01-01

    Results of spectral and photometric measurements are presented for pulsed power operated high intensity discharges (HIDs). This investigation is related to the application of a pulsed power supply for pile driving of HID lamps. Specifically, we are interested in controlling the spectral response radiation of visible and ultraviolet (UV) lines for tertiary treatment of water using UV radiation. Simulations based on a physical model of the lamps were conducted. These results relate to the radial temperature, line intensity and electrical properties (voltage, power and conductivity). Good agreement has been found between the results of the simulations and the experimental findings

  19. Quantum dynamics of an electric charge in an oscillating pulsed magnetic field

    International Nuclear Information System (INIS)

    Oliveira, I.S.; Guimaraes, A.P.; Silva, X.A. da

    1996-11-01

    The motion of a charged particle under the action of a time-dependent oscillating magnetic field has been investigated. For one and two magnetic pulses were obtained analytical expressions for the free current decay and current echo in agreement with a recently proposed classical description of electrical current in fields E and B. When the resonance condition is achieved, the axis of quantization is turned over by 90 degrees. The results suggest a magnetic pulsed resonant method to separate charged particles in a beam. (author). 12 refs

  20. Effect of counter electric field during the irradiation of pulsed x-ray on the after-pulses of GM counter

    International Nuclear Information System (INIS)

    Igarashi, Ryuji; Narita, Yuichi; Ozawa, Yasutomo.

    1979-01-01

    The authors once made it clear by using pulsed radiation that the number of spurious discharge generation in organic gas-quenching type GM counters depends on the intensity of incident radiation. This spurious discharge is peculiar to the organic gas-quenching type GM counters, which the authors named after-pulses. The present study has been carried out to find the experimental conditions to verify the delayed generation mechanism of such after-pulses in bipolar GM tubes and the conditions to give the maximum number of after-pulses generation. For this purpose, a large low electric field region, whose field intensity is variable, should be provided in the tubes. Since it has been generally impossible in the bipolar GM tubes, the provision of that region transiently has been tried. The effect of the intensity of electric field in GM tubes during irradiation on the generation of after-pulses has been investigated by changing radiation intensity, anode voltage, and irradiated position. Consideration of the results has revealed that the number of after-pulse generation can be increased by forming transient low electric field region in the bipolar GM counters of organic gas-quenching type. It was the new knowledge that the transient anode voltage to maximize the after-pulse generating factor was several tens of negative voltage even if the conditions were varied. It seems that this fact depends upon the voltage giving the conditions to maximize the probability of forming after-pulse factors. (Wakatsuki, Y.)

  1. Sensitive detection of chlorine in iron oxide by single pulse and dual pulse laser-induced breakdown spectroscopy

    Science.gov (United States)

    Pedarnig, J. D.; Haslinger, M. J.; Bodea, M. A.; Huber, N.; Wolfmeir, H.; Heitz, J.

    2014-11-01

    The halogen chlorine is hard to detect in laser-induced breakdown spectroscopy (LIBS) mainly due to its high excited state energies of 9.2 and 10.4 eV for the most intense emission lines at 134.72 nm and 837.59 nm, respectively. We report on sensitive detection of Cl in industrial iron oxide Fe2O3 powder by single-pulse (SP) and dual-pulse (DP) LIBS measurements in the near infrared range in air. In compacted powder measured by SP excitation (Nd:YAG laser, 532 nm) Cl was detected with limit of detection LOD = 440 ppm and limit of quantitation LOQ = 720 ppm. Orthogonal DP LIBS was studied on pressed Fe2O3 pellets and Fe3O4 ceramics. The transmission of laser-induced plasma for orthogonal Nd:YAG 1064 nm and ArF 193 nm laser pulses showed a significant dependence on interpulse delay time (ipd) and laser wavelength (λL). The UV pulses (λL = 193 nm) were moderately absorbed in the plasma and the Cl I emission line intensity was enhanced while IR pulses (λL = 1064 nm) were not absorbed and Cl signals were not enhanced at ipd = 3 μs. The UV laser enhancement of Cl signals is attributed to the much higher signal/background ratio for orthogonal DP excitation compared to SP excitation and to the increased plasma temperature and electron number density. This enabled measurement at a very short delay time of td ≥ 0.1 μs with respect to the re-excitation pulse and detection of the very rapidly decaying Cl emission with higher efficiency.

  2. Detection of diamond in ore using pulsed laser Raman spectroscopy

    CSIR Research Space (South Africa)

    Lamprecht, GH

    2007-10-01

    Full Text Available is necessary for correcting for fluorescence of minerals and diamond itself. Various pulsed laser wavelengths from 266 to 1064 nm were used, as well as cw lasers for comparison. Wavelength scans of the regions of interest, indicated that pulsed lasers at 532...

  3. The effect of high voltage, high frequency pulsed electric field on slain ovine cortical bone.

    Science.gov (United States)

    Asgarifar, Hajarossadat; Oloyede, Adekunle; Zare, Firuz

    2014-04-01

    High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network

  4. Novel Method of Unambiguous Moving Target Detection in Pulse-Doppler Radar with Random Pulse Repetition Interval

    Directory of Open Access Journals (Sweden)

    Liu Zhen

    2012-03-01

    Full Text Available Blind zones and ambiguities in range and velocity measurement are two important issues in traditional pulse-Doppler radar. By generating random deviations with respect to a mean Pulse Repetition Interval (PRI, this paper proposes a novel algorithm of Moving Target Detection (MTD based on the Compressed Sensing (CS theory, in which the random deviations of the PRIare converted to the Restricted Isometry Property (RIP of the observing matrix. The ambiguities of range and velocity are eliminated by designing the signal parameters. The simulation results demonstrate that this scheme has high performance of detection, and there is no ambiguity and blind zones as well. It can also shorten the coherent processing interval compared to traditional staggered PRI mode because only one pulse train is needed instead of several trains.

  5. Effect of pulsed electric fields on microbial inactivation and physico-chemical properties of whole porcine blood.

    Science.gov (United States)

    Boulaaba, Annika; Egen, Nathalie; Klein, Günter

    2014-04-01

    The objective of this study was to determine the lethal effectiveness of pulsed electric fields on the inactivation of the porcine blood endogenous microflora. Furthermore, the impact of pulsed electric field application on physico-chemical and sensory properties in this medium should be proved. Blood samples from a commercial abattoir in Germany were processed by a continuous pilot plant-pulsed electric field system at electric field strength of 11 kV/cm for treatment times of 163 and 209 µs. The applied pulse frequencies of 134 and 175 Hz correspond to an energy input of 91 and 114 kJ/kg, respectively. In these conditions, the effectiveness of pulsed electric field processing on microbial inactivation was limited: 1.35 log10 CFU/mL reduction of total aerobic plate count (p pulsed electric field-treated blood samples. Pulsed electric field processing leads to a complete hemolysis of the red blood cells, in addition significant decreased L* (lightness), a* (redness) and b* (yellowness) values (p < 0.0001) were observed. Furthermore, changes in the sensory attributes color (changed from red to dark brown) and odor (changed from fresh to musty and tangy) were noticed.

  6. Detection of uranium extraction zone by axial temperature profiles in a pulsed column for Purex process

    International Nuclear Information System (INIS)

    Tsukada, T.; Takahashi, K.

    1991-01-01

    A new method was presented for detecting uranium extraction zone in a pulsed column by means of measuring axial temperature profile originated from reaction heat during uranium extraction. Key parameters of the temperature profiles were estimated with a code developed for calculating temperature profiles in a direct-contact heat exchanger such as a pulsed column, and were verified using data from a small pulsed column simulating reaction heat with injecting hot water. Finally, the results were compared with those from an actual uranium extraction tests, indicating that the method presented was promising for detecting uranium extraction zone in a pulsed column. (author)

  7. Influence Voltage Pulse Electrical Discharge In The Water at the Endurance Fatigue Of Carbon Steel

    Directory of Open Access Journals (Sweden)

    I.A. Vakulenko

    2016-05-01

    Full Text Available Effect of pulses of electrical discharge in the water at the magnitude of the limited endurance under cyclic loading thermally hardened carbon steel was investigated. Observed increase stamina during cyclic loading a corresponding increase in the number of accumulated dislocations on the fracture surface. Using the equation of Cofino-Manson has revealed a decrease of strain loading cycle after treatment discharges. For field-cycle fatigue as a result of processing the voltage pulses carbon steel structure improvement, followed by growth of limited endurance decrease per cycle of deformation. With increasing amplitude of the voltage loop gain stamina effect on metal processing voltage pulses is reduced. The results can be used to extend the life of parts that are subject to cyclic loading.

  8. Liberation of a pinned spiral wave by a rotating electric pulse

    Science.gov (United States)

    Chen, Jiang-Xing; Peng, Liang; Ma, Jun; Ying, He-Ping

    2014-08-01

    Spiral waves may be pinned to anatomical heterogeneities in the cardiac tissue, which leads to monomorphic ventricular tachycardia. Wave emission from heterogeneities (WEH) induced by electric pulses in one direction (EP) is a promising method for liberating such waves by using heterogeneities as internal virtual pacing sites. Here, based on the WEH effect, a new mechanism of liberation by means of a rotating electric pulse (REP) is proposed in a generic model of excitable media. Compared with the EP, the REP has the advantage of opening wider time window to liberate pinned spiral. The influences of rotating direction and frequency of the REP, and the radius of the obstacles on this new mechanism are studied. We believe this strategy may improve manipulations with pinned spiral waves in heart experiments.

  9. analysis of large electromagnetic pulse simulators using the electric field integral equation method in time domain

    International Nuclear Information System (INIS)

    Jamali, J.; Aghajafari, R.; Moini, R.; Sadeghi, H.

    2002-01-01

    A time-domain approach is presented to calculate electromagnetic fields inside a large Electromagnetic Pulse (EMP) simulator. This type of EMP simulator is used for studying the effect of electromagnetic pulses on electrical apparatus in various structures such as vehicles, a reoplanes, etc. The simulator consists of three planar transmission lines. To solve the problem, we first model the metallic structure of the simulator as a grid of conducting wires. The numerical solution of the governing electric field integral equation is then obtained using the method of moments in time domain. To demonstrate the accuracy of the model, we consider a typical EMP simulator. The comparison of our results with those obtained experimentally in the literature validates the model introduced in this paper

  10. The effect of high voltage pulsed electric field on water molecular

    Science.gov (United States)

    Fan, Xuejie; Bai, Yaxiang; Ren, Ziying

    2017-10-01

    In order to study the mechanism of high voltage pulsed electric field pre-treatment on the food drying technology. In this paper, water was treated with high pulse electric field (HPEF) in different frequency, and different voltage, then, the viscosity coefficient and the surface tension coefficient of the water were measured. The results showed that indicated that the viscosity coefficient and the surface tension coefficient of the treated water can be decreased, and while HPEF pre-treatment was applied for 22.5kV at a frequency of 50Hz and 70 Hz, the surface tension and the viscosity coefficient of the pre-treatment treatment were reduced 13.1% and 7.5%, respectively.

  11. Comparison of laser diode response to pulsed electrical and radiative excitations

    International Nuclear Information System (INIS)

    Baggio, J.; Rainsant, J.M.; D'hose, C.; Lalande, P.; Musseau, O.; Leray, J.L.

    1996-01-01

    The authors have studied the electrical and optical response of two laser diodes under transient irradiation. Both diodes exhibit a positive photocurrent, which adds to the bias current, and a decrease of the optical power until extinction when dose rate is increased. Direct carrier generation in the laser cavity is a second order phenomena. The diode overall response is driven by both the substrate photocurrent and the transient conduction of current confinement regions, which decrease the net current density in the cavity and switches-off the laser emission. This behavior is in good agreement with pulsed electrical characterizations and 2D simulations

  12. Pulse number control of electrical resistance for multi-level storage based on phase change

    International Nuclear Information System (INIS)

    Nakayama, K; Takata, M; Kasai, T; Kitagawa, A; Akita, J

    2007-01-01

    Phase change nonvolatile memory devices composed of SeSbTe chalcogenide semiconductor thin film were fabricated. The resistivity of the SeSbTe system was investigated to apply to multi-level data storage. The chalcogenide semiconductor acts as a programmable resistor that has a large dynamic range. The resistance of the chalcogenide semiconductor can be set to intermediate resistances between the amorphous and crystalline states using electric pulses of a specified power, and it can be controlled by repetition of the electric pulses. The size of the memory cell used in this work is 200 nm thick with a contact area of 1 μm diameter. The resistance of the chalcogenide semiconductor gradually varies from 41 kΩ to 840 Ω within octal steps. The resistance of the chalcogenide semiconductor decreases with increasing number of applied pulses. The step-down characteristic of the resistance can be explained as the crystalline region of the active phase change region increases with increasing number of applied pulses. The extent of crystallization was also estimated by the overall resistivity of the active region of the memory cell

  13. LPS levels in root canals after the use of ozone gas and high frequency electrical pulses

    Directory of Open Access Journals (Sweden)

    Tiago André Fontoura de MELO

    2016-01-01

    Full Text Available Abstract The present study aims to verify the effect of ozone gas (OZY® System and high frequency electric pulse (Endox® System systems on human root canals previously contaminated with Escherichia colilipopolysaccharide (LPS. Fifty single-rooted teeth had their dental crowns removed and root lengths standardized to 16 mm. The root canals were prepared up to #60 hand K-files and sterilized using gamma radiation with cobalt 60. The specimens were divided into the following five groups (n = 10 based on the disinfection protocol used: OZY® System, one 120-second-pulse (OZY 1p; OZY® System, four 24-second-pulses (OZY 4p; and Endox® System (ENDOX. Contaminated and non-contaminated canals were exposed only to apyrogenic water and used as positive (C+ and negative (C- controls, respectively. LPS (O55:B55 was administered in all root canals except those belonging to group C-. After performing disinfection, LPS samples were collected from the canals using apyrogenic paper tips. Limulus Amoebocyte Lysate (LAL was used to quantify the LPS levels, and the data obtained was analyzed using one-way ANOVA. The disinfection protocols used were unable to reduce the LPS levels significantly (p = 0.019. The use of ozone gas and high frequency electric pulses was not effective in eliminating LPS from the root canals.

  14. Effects of high intensity pulsed electric field and thermal treatments on a lipase from Pseudomonas fluorescens.

    Science.gov (United States)

    Bendicho, S; Estela, C; Giner, J; Barbosa-Cánovas, G V; Martin, O

    2002-01-01

    Milk and dairy products may contain microorganisms capable of secreting lipases that cause sensory defects and technological problems in the dairy industry. In this study, the effects of thermal and high-intensity pulsed electric field (HIPEF) treatments on an extracellular lipase from Pseudomonas fluorescens, suspended in a simulated skim milk ultrafiltrate (SMUF) have been evaluated. Heat treatments applied were up to 30 min from 50 to 90 degrees C. HIPEF treatments were carried out using pilot plant facilities in a batch or continuous flow mode, where treatment chambers consisted of parallel and coaxial configuration, respectively. Samples were subjected to up to 80 pulses at electric field intensities ranging from 16.4 to 37.3 kV/cm. This resulted in a lipase that was quite resistant to heat and also to HIPEF. High (75 degrees C-15 s) and low pasteurization treatments (63 degrees C-30 min) led to inactivations of 5 and 20%, respectively. Using the batch-mode HIPEF equipment, a 62.1% maximum activity depletion was achieved after 80 pulses at 27.4 kV/cm. However, when HIPEF treatments were applied in the continuous flow mode, an inactivation rate of just 13% was achieved, after applying 80 pulses at 37.3 kV/cm and 3.5 Hz. The results of both heat and HIPEF treatments on enzyme inactivation were adjusted with good agreement to a first-order kinetic model (R2 > 62.3%).

  15. Effects of combined exposure of Micrococcus luteus to nisin and pulsed electric fields

    NARCIS (Netherlands)

    Dutreux, N.; Notermans, S.; Góngora-Nieto, M.M.; Barbosa-Cánovas, G.V.; Swanson, B.G.

    2000-01-01

    Death and injury following exposure of Micrococcus luteus to nisin and pulsed electric field (PEF) treatment were investigated in phosphate buffer (pH 6.8, σ = 4.8 ms/cm at 20°C). Four types of experiment were carried out, a single treatment with nisin (100 IU/ml at 20°C for 2 h), a single PEF

  16. Disintegration of Copper Ores by Electric Pulses / Rozdrobienie Rudy Miedzi Impulsami Elektrycznymi

    Directory of Open Access Journals (Sweden)

    Kurytnik I.

    2015-12-01

    Full Text Available The article is concerned with methods of ragging and grinding of copper ore. The proposed electric pulse technology is one of the energetically favorable methods of ragging and grinding of natural minerals and anthropogenic raw materials. This paper presents optimal parameters in processing of the product. The results obtained by grinding of copper ore using the offered technology may be used under industrial conditions in the future.

  17. A comparison of electrical and photonic pulse generation for IR-UWB on fiber links

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Caballero Jambrina, Antonio; Yu, Xianbin

    2010-01-01

    We present and compare experimental results for electrical and photonic generation of 2-Gb/s pulses for impulse radio ultra-wideband on fiber transmission systems based on direct current modulation of a semiconductor laser diode and external optical injection of a semiconductor laser diode......, respectively. We assess the performance of the two generation approaches in terms of bit-error rate after propagation over 20 km of optical fiber followed by wireless transmission....

  18. Characterization of Pressure Transients Generated by Nanosecond Electrical Pulse (nsEP) Exposure

    OpenAIRE

    Caleb C. Roth; Ronald A. Barnes Jr.; Bennett L. Ibey; Hope T. Beier; L. Christopher Mimun; Saher M. Maswadi; Mehdi Shadaram; Randolph D. Glickman

    2015-01-01

    The mechanism(s) responsible for the breakdown (nanoporation) of cell plasma membranes after nanosecond pulse (nsEP) exposure remains poorly understood. Current theories focus exclusively on the electrical field, citing electrostriction, water dipole alignment and/or electrodeformation as the primary mechanisms for pore formation. However, the delivery of a high-voltage nsEP to cells by tungsten electrodes creates a multitude of biophysical phenomena, including electrohydraulic cavitation, el...

  19. Lucifer Yellow uptake by CHO cells exposed to magnetic and electric pulses

    OpenAIRE

    Miklavčič, Damijan; Towhidi, Leila; Firoozabadi, S. M. P.; Mozdarani, Hossein

    2015-01-01

    Background The cell membrane acts as a barrier that hinders free entrance of most hydrophilic molecules into the cell. Due to numerous applications in medicine, biology and biotechnology, the introduction of impermeant molecules into biological cells has drawn considerable attention in the past years. One of the most famous methods in this field is electroporation, in which electric pulses with high intensity and short duration are applied to the cells. The aim of our study was to investigate...

  20. Effect of high-hydrostatic pressure and moderate-intensity pulsed electric field on plum.

    Science.gov (United States)

    García-Parra, J; González-Cebrino, F; Delgado-Adámez, J; Cava, R; Martín-Belloso, O; Élez-Martínez, P; Ramírez, R

    2018-03-01

    Moderate intensity pulse electric fields were applied in plum with the aim to increase bioactive compounds content of the fruit, while high-hydrostatic pressure was applied to preserve the purées. High-hydrostatic pressure treatment was compared with an equivalent thermal treatment. The addition of ascorbic acid during purée manufacture was also evaluated. The main objective of this study was to assess the effects on microorganisms, polyphenoloxidase, color and bioactive compounds of high-hydrostatic pressure, or thermal-processed plum purées made of moderate intensity pulse electric field-treated or no-moderate intensity pulse electric field-treated plums, after processing during storage. The application of moderate intensity pulse electric field to plums slightly increased the levels of anthocyanins and the antioxidant activity of purées. The application of Hydrostatic-high pressure (HHP) increased the levels of bioactive compounds in purées, while the thermal treatment preserved better the color during storage. The addition of ascorbic acid during the manufacture of plum purée was an important factor for the final quality of purées. The color and the bioactive compounds content were better preserved in purées with ascorbic acid. The no inactivation of polyphenoloxidase enzyme with treatments applied in this study affected the stability purées. Probably more intense treatments conditions (high-hydrostatic pressure and thermal treatment) would be necessary to reach better quality and shelf life during storage.

  1. Measurements of Electric Field in a Nanosecond Pulse Discharge by 4-WAVE Mixing

    Science.gov (United States)

    Baratte, Edmond; Adamovich, Igor V.; Simeni Simeni, Marien; Frederickson, Kraig

    2017-06-01

    Picosecond four-wave mixing is used to measure temporally and Picosecond four-wave mixing is used to measure temporally and spatially resolved electric field in a nanosecond pulse dielectric discharge sustained in room air and in an atmospheric pressure hydrogen diffusion flame. Measurements of the electric field, and more precisely the reduced electric field (E/N) in the plasma is critical for determination rate coefficients of electron impact processes in the plasma, as well as for quantifying energy partition in the electric discharge among different molecular energy modes. The four-wave mixing measurements are performed using a collinear phase matching geometry, with nitrogen used as the probe species, at temporal resolution of about 2 ns . Absolute calibration is performed by measurement of a known electrostatic electric field. In the present experiments, the discharge is sustained between two stainless steel plate electrodes, each placed in a quartz sleeve, which greatly improves plasma uniformity. Our previous measurements of electric field in a nanosecond pulse dielectric barrier discharge by picosecond 4-wave mixing have been done in air at room temperature, in a discharge sustained between a razor edge high-voltage electrode and a plane grounded electrode (a quartz plate or a layer of distilled water). Electric field measurements in a flame, which is a high-temperature environment, are more challenging because the four-wave mixing signal is proportional to the to square root of the difference betwen the populations of N2 ground vibrational level (v=0) and first excited vibrational level (v=1). At high temperatures, the total number density is reduced, thus reducing absolute vibrational level populations of N2. Also, the signal is reduced further due to a wider distribution of N2 molecules over multiple rotational levels at higher temperatures, while the present four-wave mixing diagnostics is using spectrally narrow output of a ps laser and a high

  2. Inactivation of Listeria innocua in skim milk by pulsed electric fields and nisin.

    Science.gov (United States)

    Calderón-Miranda, M L; Barbosa-Cánovas, G V; Swanson, B G

    1999-10-01

    Pulsed electric fields (PEF) is an emerging nonthermal processing technology used to inactivate microorganisms in liquid foods such as milk. PEF results in loss of cell membrane functionality that leads to inactivation of the microorganism. There are many processes that aid in the stability and safety of foods. The combination of different preservation factors, such as nisin and PEF, to control microorganisms should be explored. The objective of this research was to study the inactivation of Listeria innocua suspended in skim milk by PEF as well as the sensitization of PEF treated L. innocua to nisin. The selected electric field intensity was 30, 40 and 50 kV/cm and the number of pulses applied was 10.6, 21.3 and 32. The sensitization exhibited by PEF treated L. innocua to nisin was assessed for 10 or 100 IU nisin/ml. A progressive decrease in the population of L. innocua was observed for the selected field intensities, with the greatest reduction being 2 1/2 log cycles (U). The exposure of L. innocua to nisin after PEF had an additive effect on the inactivation of the microorganism as that exhibited by the PEF alone. As the electric field, number of pulses and nisin concentration increased, synergism was observed in the inactivation of L. innocua as a result of exposure to nisin after PEF. The reduction of L. innocua accomplished by exposure to 10 IU nisin/ml after 32 pulsed electric fields was 2, 2.7, and 3.4 U for an electric field intensity of 30, 40, and 50 kV/cm, respectively. Population of L. innocua subjected to 100 IU nisin/ml after PEF was 2.8-3.8 U for the selected electric field intensities and 32 pulses. The designed model for the inactivation of L. innocua as a result of the PEF followed by exposure to nisin proved to be accurate in the prediction of the inactivation of L. innocua in skim milk containing 1.2 or 37 IU nisin/ml. Inactivation of L. innocua in skim milk containing 37 IU nisin/ml resulted in a decrease in population of 3.7 U.

  3. Effect of tendon vibration during wide-pulse neuromuscular electrical stimulation (NMES) on the decline and recovery of muscle force.

    Science.gov (United States)

    Bochkezanian, Vanesa; Newton, Robert U; Trajano, Gabriel S; Vieira, Amilton; Pulverenti, Timothy S; Blazevich, Anthony J

    2017-05-02

    Neuromuscular electrical stimulation (NMES) is commonly used to activate skeletal muscles and reverse muscle atrophy in clinical populations. Clinical recommendations for NMES suggest the use of short pulse widths (100-200 μs) and low-to-moderate pulse frequencies (30-50 Hz). However, this type of NMES causes rapid muscle fatigue due to the (non-physiological) high stimulation intensities and non-orderly recruitment of motor units. The use of both wide pulse widths (1000 μs) and tendon vibration might optimize motor unit activation through spinal reflex pathways and thus delay the onset of muscle fatigue, increasing muscle force and mass. Thus, the objective of this study was to examine the acute effects of patellar tendon vibration superimposed onto wide-pulse width (1000 μs) knee extensor electrical stimulation (NMES, 30 Hz) on peak muscle force, total impulse before "muscle fatigue", and the post-exercise recovery of muscle function. Tendon vibration (Vib), NMES (STIM) or NMES superimposed onto vibration (STIM + Vib) were applied in separate sessions to 16 healthy adults. Total torque-time integral (TTI), maximal voluntary contraction torque (MVIC) and indirect measures of muscle damage were tested before, immediately after, 1 h and 48 h after each stimulus. TTI increased (145.0 ± 127.7%) in STIM only for "positive responders" to the tendon vibration (8/16 subjects), but decreased in "negative responders" (-43.5 ± 25.7%). MVIC (-8.7%) and rectus femoris electromyography (RF EMG) (-16.7%) decreased after STIM (group effect) for at least 1 h, but not after STIM + Vib. No changes were detected in indirect markers of muscle damage in any condition. Tendon vibration superimposed onto wide-pulse width NMES increased TTI only in 8 of 16 subjects, but reduced voluntary force loss (fatigue) ubiquitously. Negative responders to tendon vibration may derive greater benefit from wide-pulse width NMES alone.

  4. Pulsed currents carried by whistlers. IV. Electric fields and radiation excited by an electrode

    International Nuclear Information System (INIS)

    Stenzel, R.L.; Urrutia, J.M.; Rousculp, C.L.

    1995-01-01

    Electromagnetic properties of current pulses carried by whistler wave packets are obtained from a basic laboratory experiment. While the magnetic field and current density are described in the preceding companion paper (Part III), the present analysis starts with the electric field. The inductive and space charge electric field contributions are separately calculated in Fourier space from the measured magnetic field and Ohm's law along B 0 . Inverse Fourier transformation yields the total electric field in space and time, separated into rotational and divergent contributions. The space-charge density in whistler wave packets is obtained. The cross-field tensor conductivity is determined. The frozen-in condition is nearly satisfied, E+v e xB congruent 0. The dissipation is obtained from Poynting's theorem. The waves are collisionally damped; Landau damping is negligible. A radiation resistance for the electrode is determined. Analogous to Poynting's theorem, the transport of helicity is analyzed. Current helicity is generated by a flow of helicity between pulses traveling in opposite directions which carry opposite signs of helicity. Helicity is dissipated by collisions. These observations complete a detailed description of whistler/current pulses which can occur in various laboratory and space plasmas. copyright 1995 American Institute of Physics

  5. Effect of pulsed electric field on the rheological and colour properties of soy milk.

    Science.gov (United States)

    Xiang, Bob Y; Simpson, Marian V; Ngadi, Michael O; Simpson, Benjamin K

    2011-12-01

    The effects of pulsed electric field (PEF) treatments on rheological and colour properties of soy milk were evaluated. Flow behaviour, viscosity and rheological parameters of PEF-treated soy milk were monitored using a controlled stress rheometer. For PEF treatments, electric field intensity of 18, 20 and 22 kV cm(-1) and number of pulses of 25, 50, 75 and 100 were used. For the measurements of rheological properties of soy milk shear rates between 0 and 200 s(-1) was used. The rheological behaviour of control and the PEF-treated soy milk were described using a power law model. The PEF treatments affected the rheological properties of soy milk. Apparent viscosity of soy milk increased from 6.62 to 7.46 (10(-3) Pa s) with increase in electric field intensity from 18 to 22 kV cm(-1) and increase in the number of pulses from 0 to 100. The consistency index (K) of soy milk also changed with PEF treatments. Lightness (L*), red/greenness (a*) and yellowness/blueness (b*) of soy milk were affected by PEF treatments.

  6. An assessment of potential applications with pulsed electric field in wines

    Directory of Open Access Journals (Sweden)

    Drosou Foteini

    2017-01-01

    Full Text Available Pulsed electric fields (PEF is a non-thermal processing technology that uses instantaneous, pulses of high voltage for a short period in the range of milliseconds to microseconds; the application of high intensity electric field on toasted wood chips leads to a quick diffusion of extractable molecules. Currently most PEF studies, in the field of oenology, have been focusing on the application of PEF as a pretreatment of grape musts by examining the microbial inactivation and the enhancement of polyphenol extraction. In this study a post-treatment of wine is introduced as method to enhance the wood flavor in the wine with a green noninvasive technology. Major phenolic aldehydes that have been identified as the characteristic compounds of oak volatile compounds were selected as markers and were analyzed instrumentally to compare the influence of PEF processing to non-treated samples. PEF treated samples brought about higher concentrations of the examined oak compounds in the samples treated with PEF, which may explain the advantages of its application. The modulation of the intensity of the electric field and the period of pulses influenced the concentrations of the volatile phenols that were leached out. Differences found between the assayed treatments indicate that PEF application could be a potential practice for a rapid extraction of volatile compounds from oak.

  7. Electrochemical Performances of Diamond Like Carbon Films for Pb(II) Detection in Tap Water Using Differential Pulse Anodic Stripping Voltammetry Technique

    Czech Academy of Sciences Publication Activity Database

    Sbartai, A.; Namour, F.; Barbier, F.; Krejčí, J.; Kučerová, R.; Krejčí, T.; Neděla, Vilém; Sobota, Jaroslav; Jaffrezic-Renault, N.

    2013-01-01

    Roč. 11, č. 8 (2013), s. 1524-1529 ISSN 1546-198X Institutional support: RVO:68081731 Keywords : Diamond Like Carbon DLC * Lead Detection * Differential Pulse Anodic Stripping * Voltammetry * Tap Water Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.558, year: 2013

  8. Microdosimetric study for nanosecond pulsed electric fields on a cell circuit model with nucleus.

    Science.gov (United States)

    Denzi, Agnese; Merla, Caterina; Camilleri, Paola; Paffi, Alessandra; d'Inzeo, Guglielmo; Apollonio, Francesca; Liberti, Micaela

    2013-10-01

    Recently, scientific interest in electric pulses, always more intense and shorter and able to induce biological effects on both plasma and nuclear membranes, has greatly increased. Hence, microdosimetric models that include internal organelles like the nucleus have assumed increasing importance. In this work, a circuit model of the cell including the nucleus is proposed, which accounts for the dielectric dispersion of all cell compartments. The setup of the dielectric model of the nucleus is of fundamental importance in determining the transmembrane potential (TMP) induced on the nuclear membrane; here, this is demonstrated by comparing results for three different sets of nuclear dielectric properties present in the literature. The results have been compared, even including or disregarding the dielectric dispersion of the nucleus. The main differences have been found when using pulses shorter than 10 ns. This is due to the fact that the high spectral components of the shortest pulses are differently taken into account by the nuclear membrane transfer functions computed with and without nuclear dielectric dispersion. The shortest pulses are also the most effective in porating the intracellular structures, as confirmed by the time courses of the TMP calculated across the plasma and nuclear membranes. We show how dispersive nucleus models are unavoidable when dealing with pulses shorter than 10 ns because of the large spectral contents arriving above 100 MHz, i.e., over the typical relaxation frequencies of the dipolar mechanism of the molecules constituting the nuclear membrane and the subcellular cell compartments.

  9. Inactivation of Pseudomonas fluorescens in skim milk by combinations of pulsed electric fields and organic acids.

    Science.gov (United States)

    Fernández-Molina, Juan J; Altunakar, Bilge; Bermúdez-Aguirre, Daniela; Swanson, Barry G; Barbosa-Cánovas, Gustavo V

    2005-06-01

    Pseudomonas fluorescens suspended in skim milk was inactivated by application of pulsed electric fields (PEF) either alone or in combination with acetic or propionic acid. The initial concentration of microorganisms ranged from 10(5) to 10(6) CFU/ml. Addition of acetic acid and propionic acid to skim milk inactivated 0.24 and 0.48 log CFU/ml P. fluorescens, respectively. Sets of 10, 20, and 30 pulses were applied to the skim milk using exponentially decaying pulses with pulse lengths of 2 micros and pulse frequencies of 3 Hz. Treatment temperature was maintained between 16 and 20 degrees C. In the absence of organic acids, PEF treatment of skim milk at field intensities of 31 and 38 kV/cm reduced P. fluorescens populations by 1.0 to 1.8 and by 1.2 to 1.9 log CFU/ml, respectively. Additions of acetic and propionic acid to the skim milk in a pH range of 5.0 to 5.3 and PEF treatment at 31, 33, and 34 kV/cm, and 36, 37, and 38 kV/cm reduced the population of P. fluorescens by 1.4 and 1.8 log CFU/ml, respectively. No synergistic effect resulted from the combination of PEF with acetic or propionic acid.

  10. Adjusting Pulse Amplitude During Transcutaneous Electrical Nerve Stimulation Does Not Provide Greater Hypoalgesia.

    Science.gov (United States)

    Bergeron-Vézina, Kayla; Filion, Camille; Couture, Chantal; Vallée, Élisabeth; Laroche, Sarah; Léonard, Guillaume

    2018-03-01

    Transcutaneous electrical nerve stimulation (TENS) is an electrotherapeutic modality commonly used in rehabilitation to relieve pain. Adjusting pulse amplitude (intensity) during TENS treatment has been suggested to overcome nerve habituation. However, it is still unclear if this procedure leads to greater hypoalgesia. The aim of this study was to determine if the hypoalgesic effect of TENS is greater when pulse amplitude is adjusted throughout the TENS treatment session in chronic low-back pain patients. Randomized double-blind crossover study. Recruitment and assessment were conducted at the Clinique universitaire de réadaptation de l'Estrie (CURE) of the Faculty of Medicine and Health Sciences of the Université de Sherbrooke. Twenty-one volunteers with chronic low-back pain were enrolled and completed this investigation. Each patient received two high-frequency TENS treatments on two separate sessions: (1) with adjustment of pulse amplitude and (2) without pulse amplitude adjustment. Pain intensity and unpleasantness were assessed before, during, and after TENS application with a 10 cm visual analog scale. Both TENS conditions (with and without adjustment of intensity) decreased pain intensity and unpleasantness when compared with baseline. No difference was observed between the two stimulation conditions for both pain intensity and unpleasantness. The current results suggest that adjustment of pulse amplitude during TENS application does not provide greater hypoalgesia in individuals with chronic low-back pain. Future studies are needed to confirm these findings in other pain populations.

  11. Muscle oxygenation of vastus lateralis and medialis muscles during alternating and pulsed current electrical stimulation.

    Science.gov (United States)

    Aldayel, Abdulaziz; Muthalib, Makii; Jubeau, Marc; McGuigan, Michael; Nosaka, Kazunori

    2011-05-01

    This study compared between alternating and pulsed current electrical muscle stimulation (EMS) for muscle oxygenation and blood volume during isometric contractions. Nine healthy men (23-48 years) received alternating current EMS (2500 Hz) modulated at 75 Hz on the knee extensors of one leg, and pulsed current EMS (75 Hz) for the other leg separated by 2 weeks in a randomised, counter-balanced order. Pulse duration (400 μs), on-off ratio (5-15 s) and other stimulation parameters were matched between conditions and 30 isometric contractions were induced at the knee joint angle of 100° (0° full extension). Changes in tissue oxygenation index (∆TOI) and total hemoglobin volume (∆tHb) of vastus lateralis and medialis muscles over 30 contractions were assessed by a near-infrared spectroscopy, and were compared between conditions by a two-way repeated measures ANOVA. Peak torque produced during EMS increased over 30 contractions in response to the increase in the stimulation intensity for pulsed current, but not for the alternating current EMS. The torque during each isometric contraction was less stable in alternating than pulsed current EMS. The changes in ∆TOI amplitude during relaxation phases and ∆tHb amplitude were not significantly different between conditions. However, the decreases in ∆TOI amplitude during contraction phases from baseline were significantly (P < 0.05) greater for the pulsed current than alternating current from the 18th contraction (-15.6 ± 2.3 vs. -8.9 ± 1.8%) to 30th contraction (-10.7 ± 1.8 vs. -4.8 ± 1.5%). These results suggest that the muscles were less activated in the alternating current EMS when compared with the pulsed current EMS.

  12. Fast Change Point Detection for Electricity Market Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Berkeley, UC; Gu, William; Choi, Jaesik; Gu, Ming; Simon, Horst; Wu, Kesheng

    2013-08-25

    Electricity is a vital part of our daily life; therefore it is important to avoid irregularities such as the California Electricity Crisis of 2000 and 2001. In this work, we seek to predict anomalies using advanced machine learning algorithms. These algorithms are effective, but computationally expensive, especially if we plan to apply them on hourly electricity market data covering a number of years. To address this challenge, we significantly accelerate the computation of the Gaussian Process (GP) for time series data. In the context of a Change Point Detection (CPD) algorithm, we reduce its computational complexity from O($n^{5}$) to O($n^{2}$). Our efficient algorithm makes it possible to compute the Change Points using the hourly price data from the California Electricity Crisis. By comparing the detected Change Points with known events, we show that the Change Point Detection algorithm is indeed effective in detecting signals preceding major events.

  13. Effect of Shock Waves Generated by Pulsed Electric Discharges in Water on Yeast Cells and Virus Particles

    Science.gov (United States)

    Girdyuk, A. E.; Gorshkov, A. N.; Egorov, V. V.; Kolikov, V. A.; Snetov, V. N.; Shneerson, G. A.

    2018-02-01

    The aim of this study is to determine the optimal parameters of the electric pulses and shock waves generated by them for the soft destruction of the virus and yeast envelopes with no changes in the structure of antigenic surface albumin and in the cell morphology in order to use them to produce antivirus vaccines and in biotechnology. The pulse electric discharges in water have been studied for different values of amplitude, pulse duration and the rate of the rise in the current. A mathematical model has been developed to estimate the optimal parameters of pulsed electric charges and shock waves for the complete destruction of the yeast cell envelopes and virus particles at a minimum of pulses.

  14. Virus detection and quantification using electrical parameters

    Science.gov (United States)

    Ahmad, Mahmoud Al; Mustafa, Farah; Ali, Lizna M.; Rizvi, Tahir A.

    2014-10-01

    Here we identify and quantitate two similar viruses, human and feline immunodeficiency viruses (HIV and FIV), suspended in a liquid medium without labeling, using a semiconductor technique. The virus count was estimated by calculating the impurities inside a defined volume by observing the change in electrical parameters. Empirically, the virus count was similar to the absolute value of the ratio of the change of the virus suspension dopant concentration relative to the mock dopant over the change in virus suspension Debye volume relative to mock Debye volume. The virus type was identified by constructing a concentration-mobility relationship which is unique for each kind of virus, allowing for a fast (within minutes) and label-free virus quantification and identification. For validation, the HIV and FIV virus preparations were further quantified by a biochemical technique and the results obtained by both approaches corroborated well. We further demonstrate that the electrical technique could be applied to accurately measure and characterize silica nanoparticles that resemble the virus particles in size. Based on these results, we anticipate our present approach to be a starting point towards establishing the foundation for label-free electrical-based identification and quantification of an unlimited number of viruses and other nano-sized particles.

  15. Basic principles of thermo-acoustic energy and temporal profile detection of microwave pulses

    CERN Document Server

    Andreev, V G; Vdovin, V A

    2001-01-01

    Basic principles of a thermo-acoustic method developed for the detection of powerful microwave pulses of nanosecond duration are discussed.A proposed method is based on the registration of acoustic pulse profile originated from the thermal expansion of the volume where microwave energy was absorbed.The amplitude of excited acoustic transient is proportional to absorbed microwave energy and its temporal profile resembles one of a microwave pulse when certain conditions are satisfied.The optimal regimes of microwave pulse energy detection and sensitivity of acoustic transient registration with piezo-transducer are discussed.It was demonstrated that profile of a microwave pulse could be detected with temporal resolution of 1 - 3 nanosecond.

  16. PIEZOELECTRIC WAVEGUIDE SENSOR FOR MEASURING PULSE PRESSURE IN CLOSED LIQUID VOLUMES AT HIGH VOLTAGE ELECTRIC DISCHARGE

    Directory of Open Access Journals (Sweden)

    V. G. Zhekul

    2017-10-01

    Full Text Available Purpose. Investigations of the characteristics of pressure waves presuppose the registration of the total profile of the pressure wave at a given point in space. For these purposes, various types of «pressure to the electrical signal» transmitters (sensors are used. Most of the common sensors are unsuitable for measuring the pulse pressure in a closed water volume at high hydrostatic pressures, in particular to study the effect of a powerful high-voltage pulse discharge on increasing the inflow of minerals and drinking water in wells. The purpose of the work was to develop antijamming piezoelectric waveguide sensor for measuring pulse pressure at a close distance from a high-voltage discharge channel in a closed volume of a liquid. Methodology. We have applied the calibration method as used as a secondary standard, the theory of electrical circuits. Results. We have selected the design and the circuit solution of the waveguide pressure sensor. We have developed a waveguide pulse-pressure sensor DTX-1 with a measuring loop. This sensor makes it possible to study the spectral characteristics of pressure waves of high-voltage pulse discharge in closed volumes of liquid at a hydrostatic pressure of up to 20 MPa and a temperature of up to 80 °C. The sensor can be used to study pressure waves with a maximum amplitude value of up to 150 MPa and duration of up to 80 µs. According to the results of the calibration, the sensitivity of the developed sensor DTX-1 with a measuring loop is 0.0346 V/MPa. Originality. We have further developed the theory of designing the waveguide piezoelectric pulse pressure sensors for measuring the pulse pressure at a close distance from a high-voltage discharge channel in a closed fluid volume by controlling the attenuation of the amplitude of the pressure signal. Practical value. We have developed, created, calibrated, used in scientific research waveguide pressure pulse sensors DTX-1. We propose sensors DTX-1 for sale

  17. Developing nucleic acid-based electrical detection systems

    Directory of Open Access Journals (Sweden)

    Gabig-Ciminska Magdalena

    2006-03-01

    Full Text Available Abstract Development of nucleic acid-based detection systems is the main focus of many research groups and high technology companies. The enormous work done in this field is particularly due to the broad versatility and variety of these sensing devices. From optical to electrical systems, from label-dependent to label-free approaches, from single to multi-analyte and array formats, this wide range of possibilities makes the research field very diversified and competitive. New challenges and requirements for an ideal detector suitable for nucleic acid analysis include high sensitivity and high specificity protocol that can be completed in a relatively short time offering at the same time low detection limit. Moreover, systems that can be miniaturized and automated present a significant advantage over conventional technology, especially if detection is needed in the field. Electrical system technology for nucleic acid-based detection is an enabling mode for making miniaturized to micro- and nanometer scale bio-monitoring devices via the fusion of modern micro- and nanofabrication technology and molecular biotechnology. The electrical biosensors that rely on the conversion of the Watson-Crick base-pair recognition event into a useful electrical signal are advancing rapidly, and recently are receiving much attention as a valuable tool for microbial pathogen detection. Pathogens may pose a serious threat to humans, animal and plants, thus their detection and analysis is a significant element of public health. Although different conventional methods for detection of pathogenic microorganisms and their toxins exist and are currently being applied, improvements of molecular-based detection methodologies have changed these traditional detection techniques and introduced a new era of rapid, miniaturized and automated electrical chip detection technologies into pathogen identification sector. In this review some developments and current directions in

  18. Detection of fast burst of neutrons in the background of intense electromagnetic pulse

    International Nuclear Information System (INIS)

    Shyam, Anurag

    1999-01-01

    There are many experiments, in which fast neutron burst is emitted along with strong electromagnetic pulse. This pulse has frequency spectrum starting from few tens of khz to hard x-rays. Detecting these neutrons bursts require special measurement techniques, which are described. (author)

  19. Apoptosis induction with electric pulses - A new approach to cancer therapy with drug free

    International Nuclear Information System (INIS)

    Tang, Liling; Yao, Chenguo; Sun, Caixin

    2009-01-01

    Electrical pulses have been widely used in biomedical fields, whose applications depend on the parameters such as durations and electric intensity. Conventional electroporation (0.1-1 kV/cm, 100 μs) has been used in cell fusion, transfection and electrochemotherapy. Recent studies with high-intensity (MV/cm) electric field applications with durations of several tens of nanoseconds can affect intracellular signal transduction and intracellular structures with plasma intact, resulting in an application of intracellular manipulation. The most recent development is the finding that parameters between those two ranges could be used to induce apoptosis of cancer cells. Proposal of apoptosis induction and tumor inhibition has advantages to pursue the treatment of cancer free of cytotoxic drugs.

  20. Hydrodynamical flows in dielectric liquid in strong inhomogeneous pulsed electric field

    International Nuclear Information System (INIS)

    Tereshonok, Dmitry V; Babaeva, Natalia Yu; Naidis, George V; Smirnov, Boris M

    2016-01-01

    We consider a hydrodynamical flow of dielectric liquid near a high voltage needle-shaped electrode in a strong inhomogeneous pulsed electric field. It was shown that under a small rise time, a negative pressure area (pressure is less than critical pressure) appears near the electrode leading to the formation of a cavity in which electric breakdown can develop. A comparison of the dependence of the velocity of fluid near an electrode for two cases (taking into account the dependence of dielectric permeability of the liquid on the electric field and without taking it into account) was made. A field-dependent dielectric coefficient leads to the appearance of two local maximums of the velocities and increases the minimum pressure, thus lowering the possibility of cavitation. While under the constant value of dielectric permeability only one local maximum appears. (paper)

  1. Nanoparticle mediated ablation of breast cancer cells using a nanosecond pulsed electric field

    Science.gov (United States)

    Burford, Christopher

    In the past, both nanomaterials and various heating modalities have been researched as means for treating cancers. However, many of the current methodologies have the flaws of inconsistent tumor ablation and significant destruction of healthy cells. Based on research performed using constant radiofrequency electric fields and metallic nanoparticles (where cell necrosis is induced by the heating of these nanoparticles) we have developed a modality that simlarly uses functionalized metallic nanoparticles, specific for the T47D breast cancer cell line, and nanosecond pulsed electric fields as the hyperthermic inducer. Using both iron oxide and gold nanoparticles the results of our pilot studies indicated that up to 90% of the cancer cells were ablated given the optimal treatment parameters. These quantities of ablated cells were achieved using a cumulative exposure time 6 orders of magnitude less than most in vitro radiofrequency electric field studies.

  2. Electromagnetic Pulse of a Vertical Electric Dipole in the Presence of Three-Layered Region

    Directory of Open Access Journals (Sweden)

    D. Cheng

    2015-01-01

    Full Text Available Approximate formulas are obtained for the electromagnetic pulses due to a delta-function current in a vertical electric dipole on the planar surface of a perfect conductor coated by a dielectric layer. The new approximated formulas for the electromagnetic field in time domain are retreated analytically and some new results are obtained. Computations and discussions are carried out for the time-domain field components radiated by a vertical electric dipole in the presence of three-layered region. It is shown that the trapped-surface-wave terms should be included in the total transient field when both the vertical electric dipole and the observation point are on or near the planar surface of the dielectric-coated earth.

  3. Electricity Price Forecasting Based on AOSVR and Outlier Detection

    Institute of Scientific and Technical Information of China (English)

    Zhou Dianmin; Gao Lin; Gao Feng

    2005-01-01

    Electricity price is of the first consideration for all the participants in electric power market and its characteristics are related to both market mechanism and variation in the behaviors of market participants. It is necessary to build a real-time price forecasting model with adaptive capability; and because there are outliers in the price data, they should be detected and filtrated in training the forecasting model by regression method. In view of these points, this paper presents an electricity price forecasting method based on accurate on-line support vector regression (AOSVR) and outlier detection. Numerical testing results show that the method is effective in forecasting the electricity prices in electric power market.

  4. The Electrode Modality Development in Pulsed Electric Field Treatment Facilitates Biocellular Mechanism Study and Improves Cancer Ablation Efficacy

    OpenAIRE

    Cen, Chao; Chen, Xinhua

    2017-01-01

    Pulsed electric field treatment is now widely used in diverse biological and medical applications: gene delivery, electrochemotherapy, and cancer therapy. This minimally invasive technique has several advantages over traditional ablation techniques, such as nonthermal elimination and blood vessel spare effect. Different electrodes are subsequently developed for a specific treatment purpose. Here, we provide a systematic review of electrode modality development in pulsed electric field treatme...

  5. Neuronal excitation and permeabilization by 200-ns pulsed electric field: An optical membrane potential study with FluoVolt dye.

    Science.gov (United States)

    Pakhomov, Andrei G; Semenov, Iurii; Casciola, Maura; Xiao, Shu

    2017-07-01

    Electric field pulses of nano- and picosecond duration are a novel modality for neurostimulation, activation of Ca 2+ signaling, and tissue ablation. However it is not known how such brief pulses activate voltage-gated ion channels. We studied excitation and electroporation of hippocampal neurons by 200-ns pulsed electric field (nsPEF), by means of time-lapse imaging of the optical membrane potential (OMP) with FluoVolt dye. Electroporation abruptly shifted OMP to a more depolarized level, which was reached within 10s), so cells remained above the resting OMP level for at least 20-30s. Activation of voltage-gated sodium channels (VGSC) enhanced the depolarizing effect of electroporation, resulting in an additional tetrodotoxin-sensitive OMP peak in 4-5ms after nsPEF. Omitting Ca 2+ in the extracellular solution did not reduce the depolarization, suggesting no contribution of voltage-gated calcium channels (VGCC). In 40% of neurons, nsPEF triggered a single action potential (AP), with the median threshold of 3kV/cm (range: 1.9-4kV/cm); no APs could be evoked by stimuli below the electroporation threshold (1.5-1.9kV/cm). VGSC opening could already be detected in 0.5ms after nsPEF, which is too fast to be mediated by the depolarizing effect of electroporation. The overlap of electroporation and AP thresholds does not necessarily reflect the causal relation, but suggests a low potency of nsPEF, as compared to conventional electrostimulation, for VGSC activation and AP induction. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Understanding the response of pulsed electric field on osteoblast functions in three-dimensional mesh structures.

    Science.gov (United States)

    Kumar, A; Nune, K C; Misra, Rdk

    2016-10-01

    The endogenous electric field plays a determining role in impacting biological functions including communication with the physiological system, brain, and bone regeneration by influencing cellular functions. From this perspective, the objective of the study described here is to elucidate the effect of external electric field under dynamic conditions, in providing a guiding cue to osteoblasts in terms of cell-cell interactions and synthesis of prominent adhesion and cytoskeleton proteins. This was accomplished using pulsed direct current electric field of strength 0.1-1 V/cm. The electric field provided guided cue to the cells to migrate toward cathode. Membrane blebbing or necrosis was nearly absent in the vicinity of cathode at 0.1 and 0.5 V/cm electric field strength. Moreover, a higher cell proliferation as well as higher expression of vinculin and densely packed actin stress fibers was observed. At anode, the cells though healthy but expression of actin and vinculin was less. We underscore for the first time that the biological functionality can be favorably modulated on 3D printed scaffolds in the presence of electric field and under dynamic conditions with consequent positive effect on cell proliferation, growth, and expression level of prominent proteins. © The Author(s) 2016.

  7. Effect of electrical pulse treatment on the thermal fatigue resistance of bionic compacted graphite cast iron processed in water

    International Nuclear Information System (INIS)

    Liu, Yan; Zhou, Hong; Su, Hang; Yang, Chunyan; Cheng, Jingyan; Zhang, Peng; Ren, Luquan

    2012-01-01

    Highlights: ► Electrical pulse treatment can reduce cracks on bionic units before thermal fatigue tests. ► Electrical pulse treatment can reduce crack sources during thermal fatigue tests. ► Thermal fatigue resistance of bionic units processed in water is enhanced. ► Thermal fatigue resistance of bionic CGI processed in water is improved. -- Abstract: In order to further enhance the thermal fatigue resistance of bionic compacted graphite cast iron (CGI) which is processed by laser in water, the electrical pulse treatment is applied to improve the thermal fatigue resistance of bionic units. The results show that the electrical pulse treatment causes the supersaturated carbon atoms located in the lattice of austenite to react with the iron atoms to form the Fe 3 C. The microstructures of the bionic units processed in water are refined by the electrical pulse treatment. The cracks on the bionic units are reduced by the electrical pulse treatment before the thermal fatigue tests; and during the tests, the thermal fatigue resistance of bionic units is therefore enhanced by reducing the crack sources. By this way, the thermal fatigue resistance of bionic CGI processed in water is improved.

  8. The effect of high-frequency electrical pulses on organic tissue in root canals.

    Science.gov (United States)

    Lendini, M; Alemanno, E; Migliaretti, G; Berutti, E

    2005-08-01

    To evaluate debris and smear layer scores after application of high-frequency electrical pulses produced by the Endox Endodontic System (Lysis Srl, Nova Milanese, Italy) on intact pulp tissue and organic and inorganic residues after endodontic instrumentation. The study comprised 75 teeth planned for extraction. The teeth were randomly divided into two groups (60 teeth) and a control group (15 teeth): group 1 (30 teeth) was not subjected to instrumentation; group 2 (30 teeth) was instrumented by Hero Shaper instruments and apical stops were prepared to size 40. Each group was subdivided into subgroups A and B (15 teeth); two electrical pulses were applied to subgroups 1A and 2A (one in the apical third and one in the middle third, respectively, at 3 and 6 mm from the root apices); four electrical pulses were applied to subgroups 1B and 2B (two in the apical third, two in the middle third). The control group (15 teeth) was prepared with Hero Shapers and irrigated with 5 mL of EDTA (10%) and 5 mL of 5% NaOCl at 50 degrees C but not subjected to the electrical pulse treatment. Roots were split longitudinally and canal walls were examined at 80x, 200x, 750x, 1500x and 15,000x magnifications, using a scanning electron microscope. Smear layer and debris scores were recorded at the 3 and 6 mm levels using a five-step scoring scale and a 200-microm grid. Means were tested for significance using the one-way anova model and the Bonferroni post-hoc test. The differences between groups were considered to be statistically significant when P < 0.05. The mean value for debris scores for the three groups varied from 1.80 (+/-0.77) to 4.50 (+/-0.68). The smear layer scores for group 2 and the control specimens varied from 2.00 (+/-0.91) to 2.33 (+/-0.99). A significant difference was found in mean debris scores at the 3 and 6 mm levels between the three groups (P < 0.001). The Bonferroni post-hoc test confirmed that the difference was due to group 1. In the two subgroups treated

  9. A Test Bed for Short Pulse OA Detection of Optical Directors in Amphibious Operations

    National Research Council Canada - National Science Library

    Ertem, M

    1999-01-01

    ...) system to detect optical directors of potential threats in amphibious operations. The use of a short pulse duration allows discrimination of retroreflections from natural sources such as rock formations and vegetation...

  10. Calcium influx affects intracellular transport and membrane repair following nanosecond pulsed electric field exposure.

    Science.gov (United States)

    Thompson, Gary Lee; Roth, Caleb C; Dalzell, Danielle R; Kuipers, Marjorie; Ibey, Bennett L

    2014-05-01

    The cellular response to subtle membrane damage following exposure to nanosecond pulsed electric fields (nsPEF) is not well understood. Recent work has shown that when cells are exposed to nsPEF, ion permeable nanopores (2  nm) created by longer micro- and millisecond duration pulses. Nanoporation of the plasma membrane by nsPEF has been shown to cause a transient increase in intracellular calcium concentration within milliseconds after exposure. Our research objective is to determine the impact of nsPEF on calcium-dependent structural and repair systems in mammalian cells. Chinese hamster ovary (CHO-K1) cells were exposed in the presence and absence of calcium ions in the outside buffer to either 1 or 20, 600-ns duration electrical pulses at 16.2  kV/cm, and pore size was determined using propidium iodide and calcium green. Membrane organization was observed with morphological changes and increases in FM1-43 fluorescence. Migration of lysosomes, implicated in membrane repair, was followed using confocal microscopy of red fluorescent protein-tagged LAMP1. Microtubule structure was imaged using mEmerald-tubulin. We found that at high 600-ns PEF dosage, calcium-induced membrane restructuring and microtubule depolymerization coincide with interruption of membrane repair via lysosomal exocytosis.

  11. Pre-breakdown processes in a dielectric fluid in inhomogeneous pulsed electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Shneider, Mikhail N., E-mail: m.n.shneider@gmail.com [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Pekker, Mikhail [MMSolution, 6808 Walker Street, Philadelphia, Pennsylvania 19135 (United States)

    2015-06-14

    We consider the development of pre-breakdown cavitation nanopores appearing in the dielectric fluid under the influence of the electrostrictive stresses in the inhomogeneous pulsed electric field. It is shown that three characteristic regions can be distinguished near the needle electrode. In the first region, where the electric field gradient is greatest, the cavitation nanopores, occurring during the voltage nanosecond pulse, may grow to the size at which an electron accelerated by the field inside the pores can acquire enough energy for excitation and ionization of the liquid on the opposite pore wall, i.e., the breakdown conditions are satisfied. In the second region, the negative pressure caused by the electrostriction is large enough for the cavitation initiation (which can be registered by optical methods), but, during the voltage pulse, the pores do not reach the size at which the potential difference across their borders becomes sufficient for ionization or excitation of water molecules. And, in the third, the development of cavitation is impossible, due to an insufficient level of the negative pressure: in this area, the spontaneously occurring micropores do not grow and collapse under the influence of surface tension forces. This paper discusses the expansion dynamics of the cavitation pores and their most probable shape.

  12. Optimising the inactivation of grape juice spoilage organisms by pulse electric fields.

    Science.gov (United States)

    Marsellés-Fontanet, A Robert; Puig, Anna; Olmos, Paola; Mínguez-Sanz, Santiago; Martín-Belloso, Olga

    2009-04-15

    The effect of some pulsed electric field (PEF) processing parameters (electric field strength, pulse frequency and treatment time), on a mixture of microorganisms (Kloeckera apiculata, Saccharomyces cerevisiae, Lactobacillus plantarum, Lactobacillus hilgardii and Gluconobacter oxydans) typically present in grape juice and wine were evaluated. An experimental design based on response surface methodology (RSM) was used and results were also compared with those of a factorially designed experiment. The relationship between the levels of inactivation of microorganisms and the energy applied to the grape juice was analysed. Yeast and bacteria were inactivated by the PEF treatments, with reductions that ranged from 2.24 to 3.94 log units. All PEF parameters affected microbial inactivation. Optimal inactivation of the mixture of spoilage microorganisms was predicted by the RSM models at 35.0 kV cm(-1) with 303 Hz pulse width for 1 ms. Inactivation was greater for yeasts than for bacteria, as was predicted by the RSM. The maximum efficacy of the PEF treatment for inactivation of microorganisms in grape juice was observed around 1500 MJ L(-1) for all the microorganisms investigated. The RSM could be used in the fruit juice industry to optimise the inactivation of spoilage microorganisms by PEF.

  13. Experimental installation for excitation of semiconductors and dielectrics by picosecond pulsed electron beam and electric field

    International Nuclear Information System (INIS)

    Nasibov, A.S.; Berezhnoj, K.V.; Shapkin, P.V.; Reutova, A.G.; Shunajlov, S.A.; Yalandin, M.I.

    2009-01-01

    The experimental facility for shaping high-voltage pulses with amplitudes of 30-250 kV and durations of 100-500 ps and electron beams with a current density of up to 1000 A/cm -2 is described. The facility was built using the principle of energy compression of a pulse from a nanosecond high-voltage generator accompanied by the subsequent pulse sharpening and cutting. The setup is equipped with two test coaxial chambers for radiation excitation in semiconductor crystals by an electron beam or an electric field in air at atmospheric pressure and T = 300 K. Generation of laser radiation in the visible range under field and electron pumping was attained in ZnSSe, ZnSe, ZnCdS, and CdS (462, 480, 515, and 525 nm, respectively). Under the exposure to an electric field (up to 10 6 V x cm -1 ), the laser generation region is as large as 300-500 μm. The radiation divergence was within 5 Deg C. The maximum integral radiation power (6 kW at λ = 480 nm) was obtained under field pumping of a zinc selenide sample with a single dielectric mirror [ru

  14. Quantifying pulsed electric field-induced membrane nanoporation in single cells.

    Science.gov (United States)

    Moen, Erick K; Ibey, Bennett L; Beier, Hope T; Armani, Andrea M

    2016-11-01

    Plasma membrane disruption can trigger a host of cellular activities. One commonly observed type of disruption is pore formation. Molecular dynamic (MD) simulations of simplified lipid membrane structures predict that controllably disrupting the membrane via nano-scale poration may be possible with nanosecond pulsed electric fields (nsPEF). Until recently, researchers hoping to verify this hypothesis experimentally have been limited to measuring the relatively slow process of fluorescent markers diffusing across the membrane, which is indirect evidence of nanoporation that could be channel-mediated. Leveraging recent advances in nonlinear optical microscopy, we elucidate the role of pulse parameters in nsPEF-induced membrane permeabilization in live cells. Unlike previous techniques, it is able to directly observe loss of membrane order at the onset of the pulse. We also develop a complementary theoretical model that relates increasing membrane permeabilization to membrane pore density. Due to the significantly improved spatial and temporal resolution possible with our imaging method, we are able to directly compare our experimental and theoretical results. Their agreement provides substantial evidence that nanoporation does occur and that its development is dictated by the electric field distribution. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Nanosecond electric pulses differentially affect inward and outward currents in patch clamped adrenal chromaffin cells.

    Directory of Open Access Journals (Sweden)

    Lisha Yang

    Full Text Available This study examined the effect of 5 ns electric pulses on macroscopic ionic currents in whole-cell voltage-clamped adrenal chromaffin cells. Current-voltage (I-V relationships first established that the early peak inward current was primarily composed of a fast voltage-dependent Na+ current (INa, whereas the late outward current was composed of at least three ionic currents: a voltage-gated Ca2+ current (ICa, a Ca2+-activated K+ current (IK(Ca, and a sustained voltage-dependent delayed rectifier K+ current (IKV. A constant-voltage step protocol was next used to monitor peak inward and late outward currents before and after cell exposure to a 5 ns pulse. A single pulse applied at an electric (E-field amplitude of 5 MV/m resulted in an instantaneous decrease of ~4% in peak INa that then declined exponentially to a level that was ~85% of the initial level after 10 min. Increasing the E-field amplitude to 8 or 10 MV/m caused a twofold greater inhibitory effect on peak INa. The decrease in INa was not due to a change in either the steady-state inactivation or activation of the Na+ channel but instead was associated with a decrease in maximal Na+ conductance. Late outward current was not affected by a pulse applied at 5 MV/m. However, for a pulse applied at the higher E-field amplitudes of 8 and 10 MV/m, late outward current in some cells underwent a progressive ~22% decline over the course of the first 20 s following pulse exposure, with no further decline. The effect was most likely concentrated on ICa and IK(Ca as IKV was not affected. The results of this study indicate that in whole-cell patch clamped adrenal chromaffin cells, a 5 ns pulse differentially inhibits specific voltage-gated ionic currents in a manner that can be manipulated by tuning E-field amplitude.

  16. Electrical addressing and temporal tweezing of localized pulses in passively mode-locked semiconductor lasers

    Science.gov (United States)

    Javaloyes, J.; Camelin, P.; Marconi, M.; Giudici, M.

    2017-08-01

    This work presents an overview of a combined experimental and theoretical analysis on the manipulation of temporal localized structures (LSs) found in passively Vertical-Cavity Surface-Emitting Lasers coupled to resonant saturable absorber mirrors. We show that the pumping current is a convenient parameter for manipulating the temporal Localized Structures, also called localized pulses. While short electrical pulses can be used for writing and erasing individual LSs, we demonstrate that a current modulation introduces a temporally evolving parameter landscape allowing to control the position and the dynamics of LSs. We show that the localized pulses drifting speed in this landscape depends almost exclusively on the local parameter value instead of depending on the landscape gradient, as shown in quasi-instantaneous media. This experimental observation is theoretically explained by the causal response time of the semiconductor carriers that occurs on an finite timescale and breaks the parity invariance along the cavity, thus leading to a new paradigm for temporal tweezing of localized pulses. Different modulation waveforms are applied for describing exhaustively this paradigm. Starting from a generic model of passive mode-locking based upon delay differential equations, we deduce the effective equations of motion for these LSs in a time-dependent current landscape.

  17. Raising the avermectins production in Streptomyces avermitilis by utilizing nanosecond pulsed electric fields (nsPEFs)

    Science.gov (United States)

    Guo, Jinsong; Ma, Ruonan; Su, Bo; Li, Yinglong; Zhang, Jue; Fang, Jing

    2016-05-01

    Avermectins, a group of anthelmintic and insecticidal agents produced from Streptomyces avermitilis, are widely used in agricultural, veterinary, and medical fields. This study presents the first report on the potential of using nanosecond pulsed electric fields (nsPEFs) to improve avermectin production in S. avermitilis. The results of colony forming units showed that 20 pulses of nsPEFs at 10 kV/cm and 20 kV/cm had a significant effect on proliferation, while 100 pulses of nsPEFs at 30 kV/cm exhibited an obvious effect on inhibition of agents. Ultraviolet spectrophotometry assay revealed that 20 pulses of nsPEFs at 15 kV/cm increased avermectin production by 42% and reduced the time for reaching a plateau in fermentation process from 7 days to 5 days. In addition, the decreased oxidation reduction potential (ORP) and increased temperature of nsPEFs-treated liquid were evidenced to be closely associated with the improved cell growth and fermentation efficiency of avermectins in S. avermitilis. More importantly, the real-time RT-PCR analysis showed that nsPEFs could remarkably enhance the expression of aveR and malE in S. avermitilis during fermentation, which are positive regulator for avermectin biosynthesis. Therefore, the nsPEFs technology presents an alternative strategy to be developed to increase avermectin output in fermentation industry.

  18. Selective susceptibility to nanosecond pulsed electric field (nsPEF) across different human cell types.

    Science.gov (United States)

    Gianulis, Elena C; Labib, Chantelle; Saulis, Gintautas; Novickij, Vitalij; Pakhomova, Olga N; Pakhomov, Andrei G

    2017-05-01

    Tumor ablation by nanosecond pulsed electric fields (nsPEF) is an emerging therapeutic modality. We compared nsPEF cytotoxicity for human cell lines of cancerous (IMR-32, Hep G2, HT-1080, and HPAF-II) and non-cancerous origin (BJ and MRC-5) under strictly controlled and identical conditions. Adherent cells were uniformly treated by 300-ns PEF (0-2000 pulses, 1.8 kV/cm, 50 Hz) on indium tin oxide-covered glass coverslips, using the same media and serum. Cell survival plotted against the number of pulses displayed three distinct regions (initial resistivity, logarithmic survival decline, and residual resistivity) for all tested cell types, but with differences in LD 50 spanning as much as nearly 80-fold. The non-cancerous cells were less sensitive than IMR-32 neuroblastoma cells but more vulnerable than the other cancers tested. The cytotoxic efficiency showed no apparent correlation with cell or nuclear size, cell morphology, metabolism level, or the extent of membrane disruption by nsPEF. Increasing pulse duration to 9 µs (0.75 kV/cm, 5 Hz) produced a different selectivity pattern, suggesting that manipulation of PEF parameters can, at least for certain cancers, overcome their resistance to nsPEF ablation. Identifying mechanisms and cell markers of differential nsPEF susceptibility will critically contribute to the proper choice and outcome of nsPEF ablation therapies.

  19. Fault Detection and Isolation for Wind Turbine Electric Pitch System

    DEFF Research Database (Denmark)

    Zhu, Jiangsheng; Ma, Kuichao; Hajizadeh, Amin

    2017-01-01

    This paper presents a model-based fault detection and isolation scheme applied on electric pitch system of wind turbines. Pitch system is one of the most critical components due to its effect on the operational safety and the dynamics of wind turbines. Faults in this system should be precisely...... detected to prevent failures and decrease downtime. To detect faults of electric pitch actuators and sensors, an extended kalman filter (EKF) based multiple model adaptive estimation (MMAE) designed to estimate the states of the system. The proposed method is demonstrated in case studies. The simulation...

  20. A New Anomaly Detection System for School Electricity Consumption Data

    Directory of Open Access Journals (Sweden)

    Wenqiang Cui

    2017-11-01

    Full Text Available Anomaly detection has been widely used in a variety of research and application domains, such as network intrusion detection, insurance/credit card fraud detection, health-care informatics, industrial damage detection, image processing and novel topic detection in text mining. In this paper, we focus on remote facilities management that identifies anomalous events in buildings by detecting anomalies in building electricity consumption data. We investigated five models within electricity consumption data from different schools to detect anomalies in the data. Furthermore, we proposed a hybrid model that combines polynomial regression and Gaussian distribution, which detects anomalies in the data with 0 false negative and an average precision higher than 91%. Based on the proposed model, we developed a data detection and visualization system for a facilities management company to detect and visualize anomalies in school electricity consumption data. The system is tested and evaluated by facilities managers. According to the evaluation, our system has improved the efficiency of facilities managers to identify anomalies in the data.

  1. The density broadening in a sodium F=2 condensate detected by a pulse train

    Directory of Open Access Journals (Sweden)

    Jianing Han

    2011-09-01

    Full Text Available The dipole-blockaded sodium clock transition has been detected by high resolution microwave spectroscopy, the multiple-pulse spectroscopy. This spectroscopic technique has been first used to detect the density broadening and shifting in a Sodium Bose Einstein Condensate (BEC by probing the sodium clock-transition. Moreover, by narrowing the pulse-width of the pulses, some of the broadening mechanisms can be partially reduced. The results reported here are essential steps toward the ground-state quantum computing, few-body spectroscopy, spin squeezing and quantum metrology.

  2. Effect of high hydrostatic pressure, ultrasound and pulsed electric fields on milk composition and characteristics

    Directory of Open Access Journals (Sweden)

    Irena Jeličić

    2012-03-01

    Full Text Available High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. However, a large number of scientific researches have been dedicated to investigation of impact of these methods on changes in constituents like milk fat, milk proteins and lactose as well as changes in mechanisms like renneting properties and coagulation of milk. The aim of this research was to give an overview of changes in milk constituents induced by high hydrostatic pressure, ultrasonification and pulsed electric field treatments as well as to suggest how these changes could improve conventional processes in the dairy industry.

  3. Localization of Electrical Insulation Failures in Superconducting Collared Coils by Analysis of the Distortion of a Pulsed Magnetic Field

    CERN Document Server

    Komorowski, P A

    2000-01-01

    The localization of possible electrical faults in superconducting accelerator magnets may, in most cases, be a complex, expensive and time-consuming process. In particular, inter-turn short circuits and failures of the ground insulation are well detectable when the magnet is collared, but often disappear after disassembly for repair due to the release of the pre-stress in the coils. The fault localization method presented in this paper is based on the measurement and analysis of the magnetic field generated inside the magnet aperture by a high voltage pulse. The presence of the fault modifies the distribution of the current in the coils and produces a distortion of the magnetic field. The described method aims at locating both the longitudinal and azimuthal position of the fault-affected area. The test method, the transient case FEM models and the implemented experimental set-up are presented and discussed for the LHC dipole models.

  4. Monopole patch antenna for in vivo exposure to nanosecond pulsed electric fields.

    Science.gov (United States)

    Merla, C; Apollonio, F; Paffi, A; Marino, C; Vernier, P T; Liberti, M

    2017-07-01

    To explore the promising therapeutic applications of short nanosecond electric pulses, in vitro and in vivo experiments are highly required. In this paper, an exposure system based on monopole patch antenna is reported to perform in vivo experiments on newborn mice with both monopolar and bipolar nanosecond signals. Analytical design and numerical simulations of the antenna in air were carried out as well as experimental characterizations in term of scattering parameter (S 11 ) and spatial electric field distribution. Numerical dosimetry of the setup with four newborn mice properly placed in proximity of the antenna patch was carried out, exploiting a matching technique to decrease the reflections due to dielectric discontinuities (i.e., from air to mouse tissues). Such technique consists in the use of a matching dielectric box with dielectric permittivity similar to those of the mice. The average computed electric field inside single mice was homogeneous (better than 68 %) with an efficiency higher than 20 V m -1  V -1 for the four exposed mice. These results demonstrate the possibility of a multiple (four) exposure of small animals to short nanosecond pulses (both monopolar and bipolar) in a controlled and efficient way.

  5. Modeling high-intensity pulsed electric field inactivation of a lipase from Pseudomonas fluorescens.

    Science.gov (United States)

    Soliva-Fortuny, R; Bendicho-Porta, S; Martín-Belloso, O

    2006-11-01

    The inactivation kinetics of a lipase from Pseudomonas fluorescens (EC 3.1.1.3.) were studied in a simulated skim milk ultrafiltrate treated with high-intensity pulsed electric fields. Samples were subjected to electric field intensities ranging from 16.4 to 27.4 kV/cm for up to 314.5 micros, thus achieving a maximum inactivation of 62.1%. The suitability of describing experimental data using mechanistic first-order kinetics and an empirical model based on the Weibull distribution function is discussed. In addition, different mathematical expressions relating the residual activity values to field strength and treatment time are supplied. A first-order fractional conversion model predicted residual activity with good accuracy (A(f) = 1.018). A mechanistic insight of the model kinetics was that experimental values were the consequence of different structural organizations of the enzyme, with uneven resistance to the pulsed electric field treatments. The Weibull model was also useful in predicting the energy density necessary to achieve lipase inactivation.

  6. Domain wall manipulation in magnetic nanotubes induced by electric current pulses

    International Nuclear Information System (INIS)

    Otálora, J A; López-López, J A; Landeros, P; Núñez, A S

    2012-01-01

    We propose that the injection of electric currents can be used to independently manipulate the position and chirality of vortex-like domain walls in metallic ferromagnetic nanotubes. We support this proposal upon theoretical and numerical assessment of the magnetization dynamics driven by such currents. We show that proper interplay between the tube geometry, magnitude of the electric current and the duration of a current pulse, can be used to manipulate the position, velocity and chirality of a vortex domain wall. Our calculations suggest that domain wall velocities greater than 1 km s -1 can be achieved for tube diameters of the order of 30 nm and increasing with it. We also find that the transition from steady to precessional domain wall motion occurs for very high electric current densities, of the order of 10 13 A m -2 . Furthermore, the great stability displayed by such chiral magnetic configurations, and the reduced Ohmic loses provided by the current pulses, lead to highly reproducible and efficient domain wall reversal mechanisms.

  7. [Spectral analysis of polyphenol oxidase (PPO) and lipoxygenase (LOX) treated by pulsed electric field].

    Science.gov (United States)

    Luo, Wei; Zhang, Ruo-Bing; Chen, Jie; Wang, Li-Ming; Guan, Zhi-Cheng; Jia, Zhi-Dong

    2009-08-01

    Inactivation effect of pulsed electric field (PEF) on polyphenol oxidase (PPO) and lipoxygenase (LOX) was investigated using a laboratory PEF system with a coaxial treatment chamber. Circular dichroism (CD) and fluorescence analysis were used to study the conformation change of the protein. The experimental results show that PPO and LOX can be effectively inactivated by the PEF treatment. Inactivation effect of PPO and LOX increases with the increase in the applied electric strength and the treatment time. Activity of PPO and LOX can be reduced by 60.3% and 21.7% at 20 kV x cm(-1) after being treated for 320 micros respectively. The decrease of the negative peaks (208 and 215 nm in PPO spectra, 208 nm and 218 nm in LOX spectra) in CD spectra of PPO and LOX shows that PEF treatment caused a loss of alpha-helix and increase in beta-sheet content, indicating that conformation changes occur in the secondary structure of PPO and LOX enzyme. This effect was strengthened as the applied electric field increased: alpha-helical content of PPO and LOX was 56% and 29% after being treated at 8 kV x cm(-1), however, when the electric field was increased up to 20 kV x cm(-1), alpha-helical content of PPO and LOX decreased to 21% and 16% respectively. The decrease rate of alpha-helix and increase rate of beta-sheet in PPO are higher than LOX, indicating that the second conformation of PPO is less resistant to PEF treatment than LOX. The fluorescence intensity of LOX increases after PEF treatment. At the same time, increasing the applied pulsed electric field increases the fluorescence intensity emitted. Fluorescence measurements confirm that tertiary conformation changes occur in the local structure of LOX. However the possible mechanism of the conformation change induced by the PEF treatment is beyond the scope of the present investigation.

  8. Electric-field-induced superconductivity detected by magnetization measurements of an electric-double-layer capacitor

    International Nuclear Information System (INIS)

    Kasahara, Yuichi; Takeuchi, Yuki; Ye, Jianting; Yuan, Hongtao; Shimotani, Hidekazu; Iwasa, Yoshihiro; Nishimura, Takahiro; Sato, Tatsuya

    2010-01-01

    We report evidence for superconductivity induced by the application of strong electric fields onto the surface of a band insulator, ZrNCl, provided by the observation of a shielding diamagnetic signal. We introduced an electric-double-layer capacitor configuration and in situ magnetization measurements at low temperatures as a method to detect the novel electric-field-induced superconducting state. The results showed excellent agreement with a previous report using a transistor configuration, demonstrating that the present technique is a novel method for investigating the nonequilibrium phase induced by electric fields. (author)

  9. Dapsone Induced Methaemoglobinemia: Early Intraoperative Detection by Pulse Oximeter Desaturation

    Directory of Open Access Journals (Sweden)

    Mahmood Rafiq

    2008-01-01

    Case signifies the importance of knowledge of any preoperative drug intake and its anaesthetic implications. Also patients on dapsone therapy especially children should be monitored for methaemoglobin levels. Since children with immune thrombocy-topenic purpura are being treated with dapsone these days and many of these patients would be planned for splenectomy, monitoring of preoperative methaemoglobin levels and methaemoglobinemia as a cause of intraoperative pulse oximeter desaturation should be kept in mind.

  10. Effect of pulsed electric field treatments on permeabilization and extraction of pigments from Chlorella vulgaris.

    Science.gov (United States)

    Luengo, Elisa; Condón-Abanto, Santiago; Álvarez, Ignacio; Raso, Javier

    2014-12-01

    The effect of pulsed electric field (PEF) treatments of different intensities on the electroporation of the cytoplasmatic membrane of Chlorella vulgaris, and on the extraction of carotenoids and chlorophylls were investigated. Staining the cells with propidium iodide before and after the PEF treatment revealed the existence of reversible and irreversible electroporation. Application of PEF treatments in the range of 20-25 kV cm(-1) caused most of the population of C. vulgaris to be irreversibly electroporated even at short treatment times (5 pulses of 3 µs). However, at lower electric field strengths (10 kV cm(-1)), cells that were reversibly electroporated were observed even after 50 pulses of 3 µs. The electroporation of C. vulgaris cells by PEF higher than 15 kV cm(-1) and duration is higher than 15 µs increased significantly the extraction yield of intracellular components of C. vulgaris. The application of a 20 kV cm(-1) for 75 μs increased the extraction yield just after the PEF treatment of the carotenoids, and chlorophylls a and b 0.5, 0.7, and 0.8 times, respectively. However, further increments in electric field strength and treatment time did not cause significant increments in the extraction yield. The extraction of carotenoids from PEF-treated C. vulgaris cells after 1 h of the application of the treatment significantly increased the extraction yield in comparison to the yield obtained from the cells extracted just after the PEF treatment. After PEF treatment at 20 kV cm(-1) for 75 µs, extraction yield for carotenoids, and chlorophylls a and b increased 1.2, 1.6, and 2.1 times, respectively. A high correlation was observed between irreversible electroporation and percentage of yield increase when the extraction was conducted after 1 h of the application of PEF treatment (R: 0.93), but not when the extraction was conducted just after PEF treatment (R: 0.67).

  11. [Research on vigilance detection based on pulse wave].

    Science.gov (United States)

    Cao, Yong; Jiao, Xuejun; Pan, Jinjin; Jiang, Jin; Fu, Jiahao; Xu, Fenggang; Yang, Hanjun

    2017-12-01

    This paper studied the rule for the change of vigilance based on pulse wave. 10 participants were recruited in a 95-minute Mackworth clock test (MCT) experiment. During the experiment, the vigilance of all participants were evaluated by Karolinska sleepiness scale (KSS) and Stanford sleepiness scale (SSS), and behavior data (the reaction time and the accuracy of target) and pulse wave signal of the participants were recorded simultaneously. The result indicated that vigilance of the participants can be divided into 3 classes: the first 30 minutes for high vigilance level, the middle 30 minutes for general vigilance level, and the last 30 minutes for low vigilance level. Besides, time domain features such as amplitude of secondary peak, amplitude of peak and the latency of secondary peak decreased with the decrease of vigilance, while the amplitude of troughs increased. In terms of frequency domain features, the energy of 4 frequency band including 8.600 ~ 9.375 Hz, 11.720 ~ 12.500 Hz, 38.280 ~ 39.060 Hz and 39.060 ~ 39.840 Hz decreased with the decrease of vigilance. Finally, under the recognition model established by the 8 characteristics mentioned above, the average accuracy of three-classification results over the 10 participants was as high as 88.7%. The results of this study confirmed the feasibility of pulse wave in the evaluation of vigilance, and provided a new way for the real-time monitoring of vigilance.

  12. Influence of Pulsed Electric Fields and Mitochondria-Cytoskeleton Interactions on Cell Respiration.

    Science.gov (United States)

    Goswami, Ishan; Perry, Justin B; Allen, Mitchell E; Brown, David A; von Spakovsky, Michael R; Verbridge, Scott S

    2018-06-19

    Pulsed electric fields with microsecond pulse width (μsPEFs) are used clinically; namely, irreversible electroporation/Nanoknife is used for soft tissue tumor ablation. The μsPEF pulse parameters used in irreversible electroporation (0.5-1 kV/cm, 80-100 pulses, ∼100 μs each, 1 Hz frequency) may cause an internal field to develop within the cell because of the disruption of the outer cell membrane and subsequent penetration of the electric field. An internal field may disrupt voltage-sensitive mitochondria, although the research literature has been relatively unclear regarding whether such disruptions occur with μsPEFs. This investigation reports the influence of clinically used μsPEF parameters on mitochondrial respiration in live cells. Using a high-throughput Agilent Seahorse machine, it was observed that μsPEF exposure comprising 80 pulses with amplitudes of 600 or 700 V/cm did not alter mitochondrial respiration in 4T1 cells measured after overnight postexposure recovery. To record alterations in mitochondrial function immediately after μsPEF exposure, high-resolution respirometry was used to measure the electron transport chain state via responses to glutamate-malate and ADP and mitochondrial membrane potential via response to carbonyl cyanide-p-trifluoromethoxyphenylhydrazone. In addition to measuring immediate mitochondrial responses to μsPEF exposure, measurements were also made on cells permeabilized using digitonin and those with compromised cytoskeleton due to actin depolymerization via treatment with the drug latrunculin B. The former treatment was used as a control to tease out the effects of plasma membrane permeabilization, whereas the latter was used to investigate indirect effects on the mitochondria that may occur if μsPEFs impact the cytoskeleton on which the mitochondria are anchored. Based on the results, it was concluded that within the pulse parameters tested, μsPEFs alone do not hinder mitochondrial physiology but can be used

  13. Sterilization of liquid foods by pulsed electric fields?an innovative ultra-high temperature process

    OpenAIRE

    Reineke, Kai; Schottroff, Felix; Meneses, Nicolas; Knorr, Dietrich

    2015-01-01

    The intention of this study was to investigate the inactivation of endospores by a combined thermal and pulsed electric field (PEF) treatment. Therefore, self-cultivated spores of Bacillus subtilis and commercial Geobacillus stearothermophilus spores with certified heat resistance were utilized. Spores of both strains were suspended in saline water (5.3 mS cm−1), skim milk (0.3% fat; 5.3 mS cm−1) and fresh prepared carrot juice (7.73 mS cm−1). The combination of moderate preheating (70–90°C) ...

  14. Combined treatment with mild heat, manothermosonication and pulsed electric fields reduces microbial growth in milk

    OpenAIRE

    Halpin, R. M.; Cregenzan-Alberti, O.; Whyte, P.; Lyng, J. G.; Noci, F.

    2013-01-01

    In recent years, there has been considerable interest in non-thermal milk processing. The objective of the present study was to assess the efficacy of two non-thermal technologies (manothermosonication; MTS, and pulsed electric fields; PEF) in comparison to thermal pasteurisation, by assessing the microbial levels of each of these milk samples post-processing. Homogenised milk was subjected to MTS (frequency; 20 kHz, amplitude; 27.9 μm, pressure; 225 kPa) at two temperatures (37 °C or 55 °C),...

  15. The Preceding Voltage Pulse and Separation Welding Mechanism of Electrical Contacts

    DEFF Research Database (Denmark)

    Yang, Xiao Cheng; Huang, Jiang; Li, Zhen Biao

    2016-01-01

    In order to obtain a better understanding of the welding mechanism in contact separation, electrical endurance tests were conducted with AgSnO2 and AgNi contacts on a simulation test device. Waveforms of contact displacement, contact voltage, and current were recorded with LabVIEW during the tests......, and changes in a contact gap and heights of pips with increases in operation cycles were observed through charge-coupled device cameras. The resultant test results show that welding in separation is accompanied with a preceding voltage pulse which represents arc rather than contact bounce arc....

  16. The Rayleigh-Taylor instability under electrical pulse discharge in water

    International Nuclear Information System (INIS)

    Kononov, A.V.; Porytskyy, P.V.; Starchyk, P.D.; Voitenko, L.M.

    1999-01-01

    The development of the Rayleigh-Taylor instability is studied on the interface between both the plasma channel and liquid medium under an electrical pulse discharge in water.It is shown that,growth of the irregularities of the contact interface leads to the increasing of heat flux from the discharge channel due to the growth of an interfacial area and the incoming of water matter into a discharge channel.As a result of these processes the characteristics of the discharge may be strongly varied

  17. The formation of ozone and UV radiation from high-power pulsed electric discharges

    Science.gov (United States)

    Piskarev, I. M.; Ushkanov, V. A.; Selemir, V. D.; Spirov, G. M.; Malevannaya Pikar', I. A.; Zuimach, E. A.

    2008-09-01

    High-power electric discharges with pulse energies of from 0.15 J to 4 kJ were studied. The yields of UV photons and ozone were found to be approximately equal, which led us to conclude that discharge conditions under which UV radiation and ozone fully destroyed each other were possible. If ozone formation was suppressed, as when a negative volume charge was created in the spark gap region, the flux of UV photons reached 3 × 1023 photons/(cm2 s).

  18. Sterilization of liquid foods by pulsed electric fields – an innovative ultra-high temperature process

    OpenAIRE

    Kai eReineke; Kai eReineke; Felix eSchottroff; Nicolas eMeneses; Nicolas eMeneses; Dietrich eKnorr

    2015-01-01

    The intention of this study was to investigate the inactivation of endospores by a combined thermal and pulsed electric field (PEF) treatment. Therefore, self-cultivated spores of Bacillus subtilis and commercial Geobacillus stearothermophilus spores with certified heat resistance were utilized. Spores of both strains were suspended in saline water (5.3 mS cm-1), skim milk (0.3% fat; 5.3 mS cm-1) and fresh prepared carrot juice (7.73 mS cm-1). The combination of moderate preheating (70-90 °C)...

  19. Reduction of diazinon and dimethoate in apple juice by pulsed electric field treatment.

    Science.gov (United States)

    Zhang, Yuanyuan; Hou, Yaxi; Zhang, Yan; Chen, Jie; Chen, Fang; Liao, Xiaojun; Hu, Xiaosong

    2012-03-15

    Organophosphorus pesticides (OPPs) are widely used in agricultural production in China, and residues of OPPs in agro-products and foods have become a public health concern. Chronic exposure to OPPs can result in potential immunosuppressive effects, cytotoxicity and mutagenicity. Pulsed electric fields (PEFs) have the potential to be used as an alternative to conventional techniques of food production. The aim of the present study was to investigate the influence of PEFs on the degradation of diazinon and dimethoate added to apple juice. PEF treatment significantly promoted the degradation of both pesticides (P apple juice and in mitigating sample toxicity. Copyright © 2011 Society of Chemical Industry.

  20. Numerical Simulation on the Liquid Bridge Formation by the Applied Electric Pulse

    Science.gov (United States)

    Hong, Jin Seok; Kang, In Seok

    2010-11-01

    In this work, liquid bridge (LB) formation by the applied electric field is analyzed numerically. Numerical simulation captures the temporal behavior of liquid surface during the LB formation between a top plate and a bottom nozzle. Numerical results show the three stages of LB formation; interface elevation, impact/fast spreading and slow spreading/stabilization. The effect of the applied voltage pulse is also studied in terms of minimal electrical energy for LB formation. Non-linear behavior such as bubble trapping at the impact of liquid to plate is also captured and explained qualitatively. Grounded and floating plate is considered. The wetting criterion for LB formation is suggested and explained in terms of capillary pressure. The linear decrease of the final contact radius with the top plate contact angle is shown from the numerical results. In addition, the effects of the liquid properties on the dynamics are briefly discussed.

  1. Stressed state of a cement electrical insulation of a pulsed magnet

    International Nuclear Information System (INIS)

    Korenevskij, V.V.; Sugak, E.B.; Fedorenko, L.I.

    1985-01-01

    The stresses arising in cement electrical insulation of a pulsed magnet intended for separation and scanning of beam of secondary particles with 5-10 MeV energy are investigated during its switching. The magnet represents a single-turn construction. During its switching repulsion forces arise in copper buses which affect the core consisting of a set of iron plates. In its turn two cores trying to separate transmit impact load onto cement electrical insulation, the mechanical strength of which determines the construction durability on the whole. For selection of calculation technique the method of photoelasticity is used on models of transparent polymeric materials. Epoxy resin served as material for insulation model, duraluminium for the rest of magnet parts. It is concluded that the calculation technique for the magnet under investigation is a hingeless circular arc

  2. The anti-biofouling behavior of high voltage pulse electric field (HPEF) mediated by carbon fiber composite coating in seawater.

    Science.gov (United States)

    Feng, Tiantian; Wu, Jinyi; Chai, Ke; Yang, Pengpeng

    2018-04-25

    One of the most important research areas in the marine industry is to investigate new and effective anti-biofouling technologies. In this study, high voltage pulse electric field (HPEF) mediated by carbon fiber (CF) composite coating was utilized to prevent the fouling of bacteria, microalgae and barnacle larvae in seawater. The plate count, 2, 3, 5-triphenyl-tetrazolium chloride (TTC) reduction assay and neutral red (NR) staining and larval motility detection showed that the inactivation rates were at the highest levels, which reached 99.1%, 99.9%, 99.7%, 98.7% and 85% respectively for Pseudomonas sp., Vibrio sp., iron bacteria, Navicula sp. and the second stage nauplii of Balanus reticulatus, under the HPEF with 19 kV pulse amplitude, 23.15 kHz frequency and 0.5 duty cycle. The field-emission scanning electron microscopy (FE-SEM) of Navicula sp. revealed that the HPEF brought about the cell lysis and the cell organic matter release on the coating, which could be the mechanism of the inactivation by the HPEF. Additionally, the FE-SEM and Raman spectroscopy indicated that the HPEF hardly damaged the coating. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Elasticity and tumorigenic characteristics of cells in a monolayer after nanosecond pulsed electric field exposure.

    Science.gov (United States)

    Steuer, A; Wende, K; Babica, P; Kolb, J F

    2017-09-01

    Nanosecond pulsed electric fields (nsPEFs) applied to cells can induce different biological effects depending on pulse duration and field strength. One known process is the induction of apoptosis whereby nsPEFs are currently investigated as a novel cancer therapy. Another and probably related change is the breakdown of the cytoskeleton. We investigated the elasticity of rat liver epithelial cells WB-F344 in a monolayer using atomic force microscopy (AFM) with respect to the potential of cells to undergo malignant transformation or to develop a potential to metastasize. We found that the elastic modulus of the cells decreased significantly within the first 8 min after treatment with 20 pulses of 100 ns and with a field strength of 20 kV/cm but was still higher than the elasticity of their tumorigenic counterpart WB-ras. AFM measurements and immunofluorescent staining showed that the cellular actin cytoskeleton became reorganized within 5 min. However, both a colony formation assay and a cell migration assay revealed no significant changes after nsPEF treatment, implying that cells seem not to adopt malignant characteristics associated with metastasis formation despite the induced transient changes to elasticity and cytoskeleton that can be observed for up to 1 h.

  4. Pulsed laser deposition of semiconductor-ITO composite films on electric-field-applied substrates

    International Nuclear Information System (INIS)

    Narazaki, Aiko; Sato, Tadatake; Kawaguchi, Yoshizo; Niino, Hiroyuki; Yabe, Akira; Sasaki, Takeshi; Koshizaki, Naoto

    2002-01-01

    The DC electric-field effect on the crystallinity of II-VI semiconductor in composite systems has been investigated for CdS-ITO films fabricated via alternative pulsed laser deposition (PLD) of CdS and indium tin oxide (ITO) on electric-field-applied substrates. The alternative laser ablation was performed under irradiation of ArF excimer laser in mixture gas of helium and oxygen. The application of electric-field facilitated the preferential crystal-growth of CdS in nanometer scale at low pressure, whereas all the films grown without the field were amorphous. There is a large difference in the crystallization between the films grown on field-applied and heated substrates; the latter showed the crystal-growth with random orientations. This difference indicates that the existence of electric-field has an influence on the transformation from amorphous to crystalline phase of CdS. The driving force for the field-induced crystallization is also discussed in the light of the Joule heat

  5. A research program to assess the impact of the electromagnetic pulse on electric power systems

    Science.gov (United States)

    McConnell, B. W.; Barnes, P. R.

    A strong electromagnetic pulse (EMP) with an electric-field component on the order of tens of kilovolts per meter is produced by a nuclear detonation in or above the atmosphere. This paper presents an overview and a summary of the results to date of a program formulated to address the research and development of technologies and systems required to assess and reduce the impact of EMP on electric power systems. The technologies and systems being considered include simulation models, methods of assessment, definition of required experiments and data, development of protective hardware, and the creation or revision of operating and control procedures. Results to date include the development of relatively simple unclassified EMP environment models, the development of methods for extending EMP coupling models to the large transmission and distribution network associated with the electric power system, and the performance of a parametric study of HEMP induced surges using an appropriate EMP environment. An experiment to investigate the effect of corona on the coupling of EMP to conductors has been defined and has been performed in an EMP simulator. Experiments to determine the response of key components to simulated EMP surges and an investigation of the impact of steep-front, short-duration impulse on a selected number of the insulation systems used in electric power systems apparatus are being performed.

  6. Morphologically Aligned Cation-Exchange Membranes by a Pulsed Electric Field for Reverse Electrodialysis.

    Science.gov (United States)

    Lee, Ju-Young; Kim, Jae-Hun; Lee, Ju-Hyuk; Kim, Seok; Moon, Seung-Hyeon

    2015-07-21

    A low-resistance ion-exchange membrane is essential to achieve the high-performance energy conversion or storage systems. The formation methods for low-resistance membranes are various; one of the methods is the ion channel alignment of an ion-exchange membrane under a direct current (DC) electric field. In this study, we suggest a more effective alignment method than the process with the DC electric field. First, an ion-exchange membrane was prepared under a pulsed electric field [alternating current (AC) mode] to enhance the effectiveness of the alignment. The membrane properties and the performance in reverse electrodialysis (RED) were then examined to assess the membrane resistance and ion selectivity. The results show that the membrane electrical resistance (MER) had a lower value of 0.86 Ω cm(2) for the AC membrane than 2.13 Ω cm(2) observed for the DC membrane and 4.30 Ω cm(2) observed for the pristine membrane. Furthermore, RED achieved 1.34 W/m(2) of maximum power density for the AC membrane, whereas that for the DC membrane was found to be 1.14 W/m(2) [a RED stack assembled with CMX, used as a commercial cation-exchange membrane (CEM), showed 1.07 W/m(2)]. Thereby, the novel preparation process for a remarkable low-resistance membrane with high ion selectivity was demonstrated.

  7. X-ray emission from a nanosecond-pulse discharge in an inhomogeneous electric field at atmospheric pressure

    International Nuclear Information System (INIS)

    Zhang Cheng; Shao Tao; Ren Chengyan; Zhang Dongdong; Tarasenko, Victor; Kostyrya, Igor D.; Ma Hao; Yan Ping

    2012-01-01

    This paper describes experimental studies of the dependence of the X-ray intensity on the anode material in nanosecond high-voltage discharges. The discharges were generated by two nanosecond-pulse generators in atmospheric air with a highly inhomogeneous electric field by a tube-plate gap. The output pulse of the first generator (repetitive pulse generator) has a rise time of about 15 ns and a full width at half maximum of 30–40 ns. The output of the second generator (single pulse generator) has a rise time of about 0.3 ns and a full width at half maximum of 1 ns. The electrical characteristics and the X-ray emission of nanosecond-pulse discharge in atmospheric air are studied by the measurement of voltage-current waveforms, discharge images, X-ray count and dose. Our experimental results showed that the anode material rarely affects electrical characteristics, but it can significantly affect the X-ray density. Comparing the density of X-rays, it was shown that the highest x-rays density occurred in the diffuse discharge in repetitive pulse mode, then the spark discharge with a small air gap, and then the corona discharge with a large air gap, in which the X-ray density was the lowest. Therefore, it could be confirmed that the bremsstrahlung at the anode contributes to the X-ray emission from nanosecond-pulse discharges.

  8. An investigation for structure transformation in electric pulse modified liquid aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Qi Jingang, E-mail: Qijingang1974@sina.co [School of Material Science and Engineering, Liaoning University of Technology, Jinzhou 121001 (China); Wang Jianzhong; He Lijia; Zhao Zuofu; Du Huiling [School of Material Science and Engineering, Liaoning University of Technology, Jinzhou 121001 (China)

    2011-02-15

    The electric pulse (EP) modification of liquid metal is a novel method for grain refinement. In this work, the structure tests of EP-modified liquid aluminum were conducted and investigated using high-temperature X-ray diffractometer by virtue of the outstanding structural heredity of EP-modified liquid aluminum. The results show that the EP-modified liquid structure tends to be slack and unordered with increasing temperature similar to that of the unmodified. Nevertheless, the quantitative characterization denoted by the liquid structural parameters exhibits its discrepancy. At the modifying temperature of 750 {sup o}C, the order of degree of EP-modified liquid aluminum is remarkably strengthened and the value of average atomic number per cluster changes from 119 (no EP) up to 174 (EP) by an increase of 46%. These tests experimentally testified Wang's electric pulse modification (EPM) model that was built only by phenomenology, and hereby the mechanism of grain refinement resulting from EPM is further elucidated.

  9. Transient suppression of gap junctional intercellular communication after exposure to 100-nanosecond pulsed electric fields.

    Science.gov (United States)

    Steuer, Anna; Schmidt, Anke; Labohá, Petra; Babica, Pavel; Kolb, Juergen F

    2016-12-01

    Gap junctional intercellular communication (GJIC) is an important mechanism that is involved and affected in many diseases and injuries. So far, the effect of nanosecond pulsed electric fields (nsPEFs) on the communication between cells was not investigated. An in vitro approach is presented with rat liver epithelial WB-F344 cells grown and exposed in a monolayer. In order to observe sub-lethal effects, cells were exposed to pulsed electric fields with a duration of 100ns and amplitudes between 10 and 20kV/cm. GJIC strongly decreased within 15min after treatment but recovered within 24h. Gene expression of Cx43 was significantly decreased and associated with a reduced total amount of Cx43 protein. In addition, MAP kinases p38 and Erk1/2, involved in Cx43 phosphorylation, were activated and Cx43 became hyperphosphorylated. Immunofluorescent staining of Cx43 displayed the disassembly of gap junctions. Further, a reorganization of the actin cytoskeleton was observed whereas tight junction protein ZO-1 was not significantly affected. All effects were field- and time-dependent and most pronounced within 30 to 60min after treatment. A better understanding of a possible manipulation of GJIC by nsPEFs might eventually offer a possibility to develop and improve treatments. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. The Influence of Vesicle Shape and Medium Conductivity on Possible Electrofusion under a Pulsed Electric Field.

    Science.gov (United States)

    Liu, Linying; Mao, Zheng; Zhang, Jianhua; Liu, Na; Liu, Qing Huo

    2016-01-01

    The effects of electric field on lipid membrane and cells have been extensively studied in the last decades. The phenomena of electroporation and electrofusion are of particular interest due to their wide use in cell biology and biotechnology. However, numerical studies on the electrofusion of cells (or vesicles) with different deformed shapes are still rare. Vesicle, being of cell size, can be treated as a simple model of cell to investigate the behaviors of cell in electric field. Based on the finite element method, we investigate the effect of vesicle shape on electrofusion of contact vesicles in various medium conditions. The transmembrane voltage (TMV) and pore density induced by a pulsed field are examined to analyze the possibility of vesicle fusion. In two different medium conditions, the prolate shape is observed to have selective electroporation at the contact area of vesicles when the exterior conductivity is smaller than the interior one; selective electroporation is more inclined to be found at the poles of the oblate vesicles when the exterior conductivity is larger than the interior one. Furthermore, we find that when the exterior conductivity is lower than the internal conductivity, the pulse can induce a selective electroporation at the contact area between two vesicles regardless of the vesicle shape. Both of these two findings have important practical applications in guiding electrofusion experiments.

  11. Pulsed electric field pretreatment of rapeseed green biomass (stems) to enhance pressing and extractives recovery.

    Science.gov (United States)

    Yu, X; Gouyo, T; Grimi, N; Bals, O; Vorobiev, E

    2016-01-01

    The objective of this study was to investigate the effects of pulsed electric field (PEF) pretreatment on the valorization of extractives (proteins and polyphenols) from rapeseed green biomass (stems) by pressing. The effect of pressure, electric field strength and pulse number on the juice expression yield, total polyphenols and total proteins content in the expressed juices were studied. Experiments conducted under optimal conditions (E = 8 kV/cm, tPEF = 2 ms, P = 10 bar) permitted to increase the juice expressed yield from 34% to 81%. Significant increases in total polyphenols content (0.48 vs. 0.10 g GAE/100g DM), in total proteins content (0.14 vs. 0.07 g BSA/100g DM) and in consolidation coefficient (9.0 × 10(-8) vs. 2.2 × 10(-8)m(2)/s) were also observed after PEF pretreatment. The recovered press cake was well dehydrated with an increase of dry matter content from 8.8% to 53.0%. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Impact of high-intensity pulsed electric fields on carotenoids profile of tomato juice made of moderate-intensity pulsed electric field-treated tomatoes.

    Science.gov (United States)

    Vallverdú-Queralt, Anna; Odriozola-Serrano, Isabel; Oms-Oliu, Gemma; Lamuela-Raventós, Rosa M; Elez-Martínez, Pedro; Martín-Belloso, Olga

    2013-12-01

    The effect of pulsed electric fields (PEF) on the carotenoid content of tomato juices was studied. First, moderate-intensity PEF (MIPEF) was applied to raw tomatoes. Afterwards, MIPEF-treated and untreated tomatoes were immediately refrigerated at 4 °C for 24 h and then, they were separately ground to produce tomato juices. Juices were treated by heat treatments or by high-intensity PEF (HIPEF) and stored under refrigeration for 56 days. MIPEF treatment of tomatoes increased the content of carotenoid compounds in tomato juices. An enhancement of 63-65% in 15-cis-lycopene was observed in juices prepared with MIPEF-treated tomatoes. A slight increase in cis-lycopene isomers was observed over time, whereas other carotenoids slightly decreased. However, HIPEF treated tomato juices maintained higher carotenoid content (10-20%) through the storage time than thermally and untreated juices. The combination of MIPEF and HIPEF treatments could be used not only to produce tomato juices with high carotenoid content but also, to maintain higher the carotenoid content during storage time. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Double-pulse standoff laser-induced breakdown spectroscopy for versatile hazardous materials detection

    Energy Technology Data Exchange (ETDEWEB)

    Gottfried, Jennifer L. [U.S. Army Research Laboratory, AMSRD-ARL-WM-BD, Aberdeen Proving Ground, MD, 21005-5069 (United States)], E-mail: jennifer.gottfried@arl.army.mil; De Lucia, Frank C.; Munson, Chase A.; Miziolek, Andrzej W. [U.S. Army Research Laboratory, AMSRD-ARL-WM-BD, Aberdeen Proving Ground, MD, 21005-5069 (United States)

    2007-12-15

    We have developed a double-pulse standoff laser-induced breakdown spectroscopy (ST-LIBS) system capable of detecting a variety of hazardous materials at tens of meters. The use of a double-pulse laser improves the sensitivity and selectivity of ST-LIBS, especially for the detection of energetic materials. In addition to various metallic and plastic materials, the system has been used to detect bulk explosives RDX and Composition-B, explosive residues, biological species such as the anthrax surrogate Bacillus subtilis, and chemical warfare simulants at 20 m. We have also demonstrated the discrimination of explosive residues from various interferents on an aluminum substrate.

  14. Computer modeling of electrical and thermal performance during bipolar pulsed radiofrequency for pain relief

    International Nuclear Information System (INIS)

    Pérez, Juan J.; Pérez-Cajaraville, Juan J.; Muñoz, Víctor; Berjano, Enrique

    2014-01-01

    Purpose: Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a “strip lesion” to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. Methods: The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authors also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. Results: There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m −1 ) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. Conclusions: The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of thermal

  15. Computer modeling of electrical and thermal performance during bipolar pulsed radiofrequency for pain relief

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, Juan J. [Instituto de Investigación Interuniversitario en Bioingeniería y Tecnología Orientada al Ser Humano, Universitat Politècnica de València, Valencia 46022 (Spain); Pérez-Cajaraville, Juan J. [Pain Unit and Department of Anesthesia and Critical Care, Clínica Universidad de Navarra, University of Navarra, Pamplona 31008 (Spain); Muñoz, Víctor [Neurotherm Spain, Barcelona 08303 (Spain); Berjano, Enrique, E-mail: eberjano@eln.upv.es [Biomedical Synergy, Electronic Engineering Department, Universitat Politècnica de València 46022 (Spain)

    2014-07-15

    Purpose: Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a “strip lesion” to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. Methods: The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authors also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. Results: There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m{sup −1}) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. Conclusions: The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of

  16. Computer modeling of electrical and thermal performance during bipolar pulsed radiofrequency for pain relief.

    Science.gov (United States)

    Pérez, Juan J; Pérez-Cajaraville, Juan J; Muñoz, Víctor; Berjano, Enrique

    2014-07-01

    Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a "strip lesion" to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authors also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m(-1)) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of thermal damage zone dimension.

  17. Electromagnetic pulse research on electric power systems: Program summary and recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.R.; McConnell, B.W.; Van Dyke, J.W. (Oak Ridge National Lab., TN (United States)); Tesche, F.M. (Tesche (F.M.), Dallas, TX (United States)); Vance, E.F. (Vance (E.F.), Fort Worth, TX (United States))

    1993-01-01

    A single nuclear detonation several hundred kilometers above the central United States will subject much of the nation to a high-altitude electromagnetic pulse (BENT). This pulse consists of an intense steep-front, short-duration transient electromagnetic field, followed by a geomagnetic disturbance with tens of seconds duration. This latter environment is referred to as the magnetohydrodynamic electromagnetic pulse (NMENT). Both the early-time transient and the geomagnetic disturbance could impact the operation of the nation's power systems. Since 1983, the US Department of Energy has been actively pursuing a research program to assess the potential impacts of one or more BENT events on the nation's electric energy supply. This report summarizes the results of that program and provides recommendations for enhancing power system reliability under HENT conditions. A nominal HENP environment suitable for assessing geographically large systems was developed during the program and is briefly described in this report. This environment was used to provide a realistic indication of BEMP impacts on electric power systems. It was found that a single high-altitude burst, which could significantly disturb the geomagnetic field, may cause the interconnected power network to break up into utility islands with massive power failures in some areas. However, permanent damage would be isolated, and restoration should be possible within a few hours. Multiple bursts would likely increase the blackout areas, component failures, and restoration time. However, a long-term blackout of many months is unlikely because major power system components, such as transformers, are not likely to be damaged by the nominal HEND environment. Moreover, power system reliability, under both HENT and normal operating conditions, can be enhanced by simple, and often low cost, modifications to current utility practices.

  18. Electromagnetic pulse research on electric power systems: Program summary and recommendations. Power Systems Technology Program

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.R.; McConnell, B.W.; Van Dyke, J.W. [Oak Ridge National Lab., TN (United States); Tesche, F.M. [Tesche (F.M.), Dallas, TX (United States); Vance, E.F. [Vance (E.F.), Fort Worth, TX (United States)

    1993-01-01

    A single nuclear detonation several hundred kilometers above the central United States will subject much of the nation to a high-altitude electromagnetic pulse (BENT). This pulse consists of an intense steep-front, short-duration transient electromagnetic field, followed by a geomagnetic disturbance with tens of seconds duration. This latter environment is referred to as the magnetohydrodynamic electromagnetic pulse (NMENT). Both the early-time transient and the geomagnetic disturbance could impact the operation of the nation`s power systems. Since 1983, the US Department of Energy has been actively pursuing a research program to assess the potential impacts of one or more BENT events on the nation`s electric energy supply. This report summarizes the results of that program and provides recommendations for enhancing power system reliability under HENT conditions. A nominal HENP environment suitable for assessing geographically large systems was developed during the program and is briefly described in this report. This environment was used to provide a realistic indication of BEMP impacts on electric power systems. It was found that a single high-altitude burst, which could significantly disturb the geomagnetic field, may cause the interconnected power network to break up into utility islands with massive power failures in some areas. However, permanent damage would be isolated, and restoration should be possible within a few hours. Multiple bursts would likely increase the blackout areas, component failures, and restoration time. However, a long-term blackout of many months is unlikely because major power system components, such as transformers, are not likely to be damaged by the nominal HEND environment. Moreover, power system reliability, under both HENT and normal operating conditions, can be enhanced by simple, and often low cost, modifications to current utility practices.

  19. Detection of acrolein and acrylonitrile with a pulsed room temperature quantum cascade laser

    Science.gov (United States)

    Manne, J.; Jäger, W.; Tulip, J.

    2010-06-01

    We investigated the use of a pulsed, distributed feedback quantum cascade laser centered at 957 cm-1 in combination with an astigmatic Herriot cell with 250 m path length for the detection of acrolein and acrylonitrile. These molecules have been identified as hazardous air-pollutants because of their adverse health effects. The spectrometer utilizes the intra-pulse method, where a linear frequency down-chirp, that is induced when a top-hat current pulse is applied to the laser, is used for sweeping across the absorption line. Up to 450 ns long pulses were used for these measurements which resulted in a spectral window of ~2.2 cm-1. A room temperature mercury-cadmium-telluride detector was used, resulting in a completely cryogen free spectrometer. We demonstrated detection limits of ~3 ppb for acrylonitrile and ~6 ppb for acrolein with ~10 s averaging time. Laser characterization and optimization of the operational parameters for sensitivity improvement are discussed.

  20. Pulsed ultrasound modulated optical tomography with harmonic lock-in holography detection.

    Science.gov (United States)

    Ruan, Haowen; Mather, Melissa L; Morgan, Stephen P

    2013-07-01

    A method that uses digital heterodyne holography reconstruction to extract scattered light modulated by a single-cycle ultrasound (US) burst is demonstrated and analyzed. An US burst is used to shift the pulsed laser frequency by a series of discrete harmonic frequencies which are then locked on a CCD. The analysis demonstrates that the unmodulated light's contribution to the detected signal can be canceled by appropriate selection of the pulse repetition frequency. It is also shown that the modulated signal can be maximized by selecting a pulse sequence which consists of a pulse followed by its inverted counterpart. The system is used to image a 12 mm thick chicken breast with 2 mm wide optically absorbing objects embedded at the midplane. Furthermore, the method can be revised to detect the nonlinear US modulated signal by locking at the second harmonic US frequency.

  1. Quality stability and sensory attributes of apple juice processed by thermosonication, pulsed electric field and thermal processing.

    Science.gov (United States)

    Sulaiman, Alifdalino; Farid, Mohammed; Silva, Filipa Vm

    2017-04-01

    Worldwide, apple juice is the second most popular juice, after orange juice. It is susceptible to enzymatic browning spoilage by polyphenoloxidase, an endogenous enzyme. In this study, Royal Gala apple juice was treated by thermosonication (TS: 1.3 W/mL, 58 ℃, 10 min), pulsed electric field (PEF: 24.8 kV/cm, 60 pulses, 169 µs treatment time, 53.8 ℃) and heat (75 ℃, 20 min) and stored at 3.0 ℃ and 20.0 ℃ for 30 days. A sensory analysis was carried out after processing. The polyphenoloxidase activity, antioxidant activity and total color difference of the apple juice were determined before and after processing and during storage. The sensory analysis revealed that thermosonication and pulsed electric field juices tasted differently from the thermally treated juice. Apart from the pulsed electric field apple juice stored at room temperature, the processed juice was stable during storage, since the pH and soluble solids remained constant and fermentation was not observed. Polyphenoloxidase did not reactivate during storage. Along storage, the juices' antioxidant activity decreased and total color difference increased (up to 6.8). While the antioxidant activity increased from 86 to 103% with thermosonication and was retained after pulsed electric field, thermal processing reduced it to 67%. The processing increased the total color difference slightly. No differences in the total color difference of the juices processed by the three methods were registered after storage. Thermosonication and pulsed electric field could possibly be a better alternative to thermal preservation of apple juice, but refrigerated storage is recommended for pulsed electric field apple juice.

  2. [Fluorescence polarization used to investigate the cell membrane fluidity of Saccharomyces cerevisiae treated by pulsed electric field].

    Science.gov (United States)

    Zhang, Ying; Zeng, Xin-An; Wen, Qi-Biao; Li, Lin

    2008-01-01

    To know the lethal mechanism of microorganisms under pulsed electric field treatment, the relationship between the inactivation of Saccharomyces cerevisiae (CICC1308) cell and the permeability and fluidity changes of its cell membrane treated by pulsed electric field (0-25 kV x cm(-1), 0-266 ms) was investigated. With 1,6-diphenyl-1,3,5-hexatriene (DPH) used as a probe, the cell membrane fluidity of Saccharomyces cerevisiae treated by pulsed electric field was expressed by fluorescence polarization. Results showed that the cell membrane fluidity decreases when the electric flied strength is up to 5 kV x cm(-1), and decreases with the increase in electric field strength and treatment time. The plate counting method and ultraviolet spectrophotometer were used to determine the cell viability and to investigate the cell membrane permeability, respectively, treated by pulsed electric field. Results showed that the lethal ratio and the content of protein and nucleic acid leaked from intracellular plasma increased with the increase in the electric field strength and the extension of treatment time. Even in a quite lower electric field of 5 kV x cm(-1) with a tiny microorganism lethal level, the increase in UV absorption value and the decrease in fluidity were significant. It was demonstrated that the cell membrane fluidity decreases with the increase in lethal ratio and cell membrane permeability. The viscosity of cell membrane increases with the decrease in fluidity. These phenomena indicated that cell membrane is one of the most key sites during the pulsed electric field treatment, and the increased membrane permeability and the decreased cell membrane fluidity contribute to the cell death.

  3. Guiding of Long-Distance Electric Discharges by Combined Femtosecond and Nanosecond Pulses Emitted by Hybrid KrF Laser System

    Science.gov (United States)

    2014-01-30

    laser pulse initiated HV discharge with a time delay of tens nanoseconds – evidently it is developing due to an avalanche -like growth of electron...AFRL-AFOSR-UK-TR-2014-0040 Guiding of long-distance electric discharges by combined femtosecond and nanosecond pulses emitted by...and guiding electric discharge , KrF laser, femtosecond pulse , nanosecond pulse , filamentation, plasma channel, lightning control, laser control of

  4. Sensitive detection of acrolein and acrylonitrile with a pulsed quantum-cascade laser

    Science.gov (United States)

    Manne, J.; Lim, A.; Tulip, J.; Jäger, W.

    2012-05-01

    We report on spectroscopic measurements of acrolein and acrylonitrile at atmospheric pressure using a pulsed distributed feedback quantum-cascade laser in combination with intra- and inter-pulse techniques and compare the results. The measurements were done in the frequency region around 957 cm-1. In the inter-pulse technique, the laser is excited with short current pulses (5-10 ns), and the pulse amplitude is modulated with an external current ramp resulting in a ˜2.3 cm-1 frequency scan. In the intra-pulse technique, a linear frequency down-chirp during the pulse is used for sweeping across the absorption line. Long current pulses up to 500 ns were used for these measurements which resulted in a spectral window of ˜2.2 cm-1 during the down-chirp. These comparatively wide spectral windows facilitated the measurements of the relatively broad absorption lines (˜1 cm-1) of acrolein and acrylonitrile. The use of a room-temperature mercury-cadmium-telluride detector resulted in a completely cryogen-free spectrometer. We demonstrate ppb level detection limits within a data acquisition time of ˜10 s with these methodologies.

  5. Detection of electric field around field-reversed configuration plasma

    International Nuclear Information System (INIS)

    Ikeyama, Taeko; Hiroi, Masanori; Nogi, Yasuyuki; Ohkuma, Yasunori

    2010-01-01

    Electric-field probes consisting of copper plates are developed to measure electric fields in a vacuum region around a plasma. The probes detect oscillating electric fields with a maximum strength of approximately 100 V/m through a discharge. Reproducible signals from the probes are obtained with an unstable phase dominated by a rotational instability. It is found that the azimuthal structure of the electric field can be explained by the sum of an n=2 mode charge distribution and a convex-surface electron distribution on the deformed separatrix at the unstable phase. The former distribution agrees with that anticipated from the diamagnetic drift motions of plasma when the rotational instability occurs. The latter distribution suggests that an electron-rich plasma covers the separatrix.

  6. Amplifiable DNA from Gram-negative and Gram-positive bacteria by a low strength pulsed electric field method

    Science.gov (United States)

    Vitzthum, Frank; Geiger, Georg; Bisswanger, Hans; Elkine, Bentsian; Brunner, Herwig; Bernhagen, Jürgen

    2000-01-01

    An efficient electric field-based procedure for cell disruption and DNA isolation is described. Isoosmotic suspensions of Gram-negative and Gram-positive bacteria were treated with pulsed electric fields of Pulses had an exponential decay waveform with a time constant of 3.4 µs. DNA yield was linearly dependent on time or pulse number, with several thousand pulses needed. Electrochemical side-effects and electrophoresis were minimal. The lysates contained non-fragmented DNA which was readily amplifiable by PCR. As the method was not limited to samples of high specific resistance, it should be applicable to physiological fluids and be useful for genomic and DNA diagnostic applications. PMID:10734214

  7. Verification and Analysis of Implementing Virtual Electric Devices in Circuit Simulation of Pulsed DC Electrical Devices in the NI MULTISIM 10.1 Environment

    Directory of Open Access Journals (Sweden)

    V. A. Solov'ev

    2015-01-01

    Full Text Available The paper presents the analysis results of the implementation potential and evaluation of the virtual electric devices reliability when conducting circuit simulation of pulsed DC electrical devices in the NI Multisim 10.1environment. It analyses metrological properties of electric measuring devices and sensors of the NI Multisim 10.1environment. To calculate the reliable parameters of periodic non-sinusoidal electrical values based on their physical feasibility the mathematical expressions have been defined.To verify the virtual electric devices a circuit model of the power section of buck DC converter with enabled devices under consideration at its input and output is used as a consumer of pulse current of trapezoidal or triangular form. It is used as an example to show a technique to verify readings of virtual electric measuring devices in the NI Multisim 10.1environment.It is found that when simulating the pulsed DC electric devices to measure average and RMS voltage supply and current consumption values it is advisable to use the probe. Electric device power consumption read from the virtual power meter is equal to its average value, and its displayed power factor is inversely proportional to the input current form factor. To determine the RMS pulsed DC current by ammeter and multi-meter it is necessary to measure current by these devices in DC and AC modes, and then determine the RMS value of measurement results.Virtual electric devices verification has proved the possibility of their application to determine the energy performance of transistor converters for various purposes in the circuit simulation in the NI 10.1 Multisim environment, thus saving time of their designing.

  8. Characterization of carbon fiber polymer matrix composites subjected to simultaneous application of electric current pulse and low velocity impact

    Science.gov (United States)

    Hart, Robert James

    2011-12-01

    The use of composite materials in aerospace, electronics, and wind industries has become increasingly common, and these composite components are required to carry mechanical, electrical, and thermal loads simultaneously. A unique property of carbon fiber composites is that when an electric current is applied to the specimen, the mechanical strength of the specimen increases. Previous studies have shown that the higher the electric current, the greater the increase in impact strength. However, as current passes through the composite, heat is generated through Joule heating. This Joule heating can cause degradation of the composite and thus a loss in strength. In order to minimize the negative effects of heating, it is desired to apply a very high current for a very short duration of time. This thesis investigated the material responses of carbon fiber composite plates subjected to electrical current pulse loads of up to 1700 Amps. For 32 ply unidirectional IM7/977-3 specimens, the peak impact load and absorbed energy increased slightly with the addition of a current pulse at the time of an impact event. In 16 ply cross-ply IM7/977-2 specimens, the addition of the current pulse caused detrimental effects due to electrical arcing at the interface between the composite and electrodes. Further refinement of the experimental setup should minimize the risk of electrical arcing and should better elucidate the effects of a current pulse on the impact strength of the specimens.

  9. Technical specifications manual for the MARK-1 pulsed ionizing radiation detection system

    International Nuclear Information System (INIS)

    Lawrence, R.S.; Harker, Y.D.; Jones, J.L.; Hoggan, J.M.

    1993-03-01

    The MARK-1 detection system was developed by the Idaho National Engineering Laboratory for the US Department of Energy Office of Arms Control and Nonproliferation. The completely portable system was designed for the detection and analysis of intense photon emissions from pulsed ionizing radiation sources. This manual presents the technical design specifications for the MARK-1 detection system and was written primarily to assist the support or service technician in the service, calibration, and repair of the system. The manual presents the general detection system theory, the MARK-1 component design specifications, the acquisition and control software, the data processing sequence, and the system calibration procedure. A second manual entitled: Volume 2: Operations Manual for the MARK-1 Pulsed Ionizing Radiation Detection System (USDOE Report WINCO-1108, September 1992) provides a general operational description of the MARK-1 detection system. The Operations Manual was written primarily to assist the field operator in system operations and analysis of the data

  10. Technical specifications manual for the MARK-1 pulsed ionizing radiation detection system. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, R.S.; Harker, Y.D.; Jones, J.L.; Hoggan, J.M.

    1993-03-01

    The MARK-1 detection system was developed by the Idaho National Engineering Laboratory for the US Department of Energy Office of Arms Control and Nonproliferation. The completely portable system was designed for the detection and analysis of intense photon emissions from pulsed ionizing radiation sources. This manual presents the technical design specifications for the MARK-1 detection system and was written primarily to assist the support or service technician in the service, calibration, and repair of the system. The manual presents the general detection system theory, the MARK-1 component design specifications, the acquisition and control software, the data processing sequence, and the system calibration procedure. A second manual entitled: Volume 2: Operations Manual for the MARK-1 Pulsed Ionizing Radiation Detection System (USDOE Report WINCO-1108, September 1992) provides a general operational description of the MARK-1 detection system. The Operations Manual was written primarily to assist the field operator in system operations and analysis of the data.

  11. Combination pulsed electric field with ethanol solvent for Nannochloropsis sp. extraction

    Science.gov (United States)

    Nafis, Ghazy Ammar; Mumpuni, Perwitasari Yekti; Indarto, Budiman, Arief

    2015-12-01

    Nowadays, energy is one of human basic needs. As the human population increased, energy consumption also increased. This condition causes energy depletion. In case of the situation, alternative energy is needed to replace existing energy. Microalgae is chosen to become one of renewable energy resource, especially biodiesel, because it contains high amount of lipid instead of other feedstock which usually used. Fortunately, Indonesia has large area of water and high intensity of sunlight so microalgae cultivation becomes easier. Nannochloropsis sp., one of microalgae species, becomes the main focus because of its high lipid content. Many ways to break the cell wall of microalgae so the lipid content inside the microalgae will be released, for example conventional extraction, ultrasonic wave extraction, pressing, and electrical method. The most effective way for extraction is electrical method such as pulsed electric field method (PEF). The principal work of this method is by draining the electrical current into parallel plate. Parallel plate will generate the electrical field to break microalgae cell wall and the lipid will be released. The aim of this work is to evaluate two-stage procedure for extraction of useful components from microalgae Nannochloropsis sp. The first stage of this procedure includes pre-treatment of microalgae by ethanol solvent extraction and the second stage applies the PEF extraction using a binary mixture of water and ethanol solvent. Ethanol is chosen as solvent because it's safer to be used and easier to be handled than other solvent. Some variables that used to study the most effective operation conditions are frequency and duty cycle for microalgae. The optimum condition based on this research are at frequency 1 Hz and duty cycle 13%.

  12. Electrical properties of multilayer (DLC-TiC) films produced by pulsed laser deposition

    Science.gov (United States)

    Alawajji, Raad A.; Kannarpady, Ganesh K.; Nima, Zeid A.; Kelly, Nigel; Watanabe, Fumiya; Biris, Alexandru S.

    2018-04-01

    In this work, pulsed laser deposition was used to produce a multilayer diamond like carbon (ML (DLC-TiC)) thin film. The ML (DLC-TiC) films were deposited on Si (100) and glass substrates at various substrate temperatures in the range of 20-450 °C. Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), and atomic force microscopy were utilized to characterize the prepared films. Raman analysis revealed that as the substrate temperature increased, the G-peak position shifted to a higher raman shift and the full width at half maximum of the G and D bands decreased. XPS analysis indicated a decrease in sp3/sp2 ratio and an increase in Ti-C bond intensity when the substrate temperature was increased. Additionally, the surface roughness of ML (DLC-TiC) filmswas affected by the type and temperature of the substrate. The electrical measurement results indicated that the electrical resistivity of the ML (DLC-TiC) film deposited on Si and glass substrates showed the same behavior-the resistivity decreased when substrate temperature increased. Furthermore, the ML (DLC-TiC) films deposited on silicon showed lower electrical resistivity, dropping from 8.39E-4 Ω-cm to 5.00E-4 Ω-cm, and, similarly, the films on the glass substrate displayed a drop in electrical resistivity from 1.8E-2 Ω-cm to 1.2E-3 Ω-cm. These enhanced electrical properties indicate that the ML (DLC-TiC) films have widespread potential as transducers for biosensors in biological research; electrochemical electrodes, because these films can be chemically modified; biocompatible coatings for medicals tools; and more.

  13. Relationship between Sublethal Injury and Inactivation of Yeast Cells by the Combination of Sorbic Acid and Pulsed Electric Fields▿

    OpenAIRE

    Somolinos, M.; García, D.; Condón, S.; Mañas, P.; Pagán, R.

    2007-01-01

    The objective of this study was to investigate the occurrence of sublethal injury after the pulsed-electric-field (PEF) treatment of two yeasts, Dekkera bruxellensis and Saccharomyces cerevisiae, as well as the relation of sublethal injury to the inactivating effect of the combination of PEF and sorbic acid. PEF caused sublethal injury in both yeasts: more than 90% of surviving D. bruxellensis cells and 99% of surviving S. cerevisiae cells were sublethally injured after 50 pulses at 12 kV/cm ...

  14. The Electrode Modality Development in Pulsed Electric Field Treatment Facilitates Biocellular Mechanism Study and Improves Cancer Ablation Efficacy.

    Science.gov (United States)

    Cen, Chao; Chen, Xinhua

    2017-01-01

    Pulsed electric field treatment is now widely used in diverse biological and medical applications: gene delivery, electrochemotherapy, and cancer therapy. This minimally invasive technique has several advantages over traditional ablation techniques, such as nonthermal elimination and blood vessel spare effect. Different electrodes are subsequently developed for a specific treatment purpose. Here, we provide a systematic review of electrode modality development in pulsed electric field treatment. For electrodes invented for experiment in vitro, sheet electrode and electrode cuvette, electrodes with high-speed fluorescence imaging system, electrodes with patch-clamp, and electrodes with confocal laser scanning microscopy are introduced. For electrodes invented for experiment in vivo, monopolar electrodes, five-needle array electrodes, single-needle bipolar electrode, parallel plate electrodes, and suction electrode are introduced. The pulsed electric field provides a promising treatment for cancer.

  15. Effect of electric pulse modification on mircostructure and properties of Ni-rich Al-Si piston alloy

    Directory of Open Access Journals (Sweden)

    Bing Wang

    2016-03-01

    Full Text Available In order to improve the properties of Ni-rich (2.5wt.% Al-Si piston alloy, electric pulse modification was applied in fabricating the Ni-rich Al-Si piston alloy in this study. The effect of electric pulse modification on the mechanical properties of the Ni-rich Al-Si piston alloy was studied using optical microscope (OM, scanning electron microscope (SEM, X-ray diffraction (XRD, microhardness measurement and tensile strength testing. The results showed that the microstructures of Ni-rich Al-Si piston alloy treated by electric pulse modification were refined, the solid solubility of Cu, Ni, Si, etc. in α-Al matrix was improved, and furthermore, the microhardness and high-temperature tensile strength were increased by 9.41% and 17.5%, respectively. The distribution of second phases was also more uniform compared with that of a non-modified sample.

  16. Evaluation of bistable systems versus matched filters in detecting bipolar pulse signals

    OpenAIRE

    Duan, Fabing; Abbott, Derek; Gao, Qisheng

    2004-01-01

    This paper presents a thorough evaluation of a bistable system versus a matched filter in detecting bipolar pulse signals. The detectability of the bistable system can be optimized by adding noise, i.e. the stochastic resonance (SR) phenomenon. This SR effect is also demonstrated by approximate statistical detection theory of the bistable system and corresponding numerical simulations. Furthermore, the performance comparison results between the bistable system and the matched filter show that...

  17. Numerical evaluation of lactoperoxidase inactivation during continuous pulsed electric field processing.

    Science.gov (United States)

    Buckow, Roman; Semrau, Julius; Sui, Qian; Wan, Jason; Knoerzer, Kai

    2012-01-01

    A computational fluid dynamics (CFD) model describing the flow, electric field and temperature distribution of a laboratory-scale pulsed electric field (PEF) treatment chamber with co-field electrode configuration was developed. The predicted temperature increase was validated by means of integral temperature studies using thermocouples at the outlet of each flow cell for grape juice and salt solutions. Simulations of PEF treatments revealed intensity peaks of the electric field and laminar flow conditions in the treatment chamber causing local temperature hot spots near the chamber walls. Furthermore, thermal inactivation kinetics of lactoperoxidase (LPO) dissolved in simulated milk ultrafiltrate were determined with a glass capillary method at temperatures ranging from 65 to 80 °C. Temperature dependence of first order inactivation rate constants was accurately described by the Arrhenius equation yielding an activation energy of 597.1 kJ mol(-1). The thermal impact of different PEF processes on LPO activity was estimated by coupling the derived Arrhenius model with the CFD model and the predicted enzyme inactivation was compared to experimental measurements. Results indicated that LPO inactivation during combined PEF/thermal treatments was largely due to thermal effects, but 5-12% enzyme inactivation may be related to other electro-chemical effects occurring during PEF treatments. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  18. Structural properties and digestibility of pulsed electric field treated waxy rice starch.

    Science.gov (United States)

    Zeng, Feng; Gao, Qun-Yu; Han, Zhong; Zeng, Xin-An; Yu, Shu-Juan

    2016-03-01

    Waxy rice starch was subjected to pulsed electric field (PEF) treatment at intensity of 30, 40 and 50kVcm(-1). The impact of PEF treatment on the granular morphology, molecular weight, semi-crystalline structure, thermal properties, and digestibility were investigated. The micrographs suggested that electric energy could act on the granule structure of starch granule, especially at high intensity of 50kVcm(-1). Gelatinization onset temperature, peak temperature, conclusion temperature and enthalpy value of PEF treated starches were lower than that of native starch. The 9nm lamellar peak of PEF treated starches decreased as revealed by small angle X-ray scattering. The relative crystallinity of treated starches decreased as the increase of electric field intensity. Increased rapidly digestible starch level and decreased slowly digestible starch level was found on PEF treated starches. These results would imply that PEF treatment induced structural changes in waxy rice starch significantly affected its digestibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Evaluation of pulsed electric fields technology for liquid whole egg pasteurization.

    Science.gov (United States)

    Monfort, S; Gayán, E; Raso, J; Condón, S; Alvarez, I

    2010-10-01

    This investigation evaluated the lethal efficiency of pulsed electric fields (PEFs) to pasteurize liquid whole egg (LWE). To achieve this aim, we describe the inactivation of Salmonella Enteritidis and the heat resistant Salmonella Senftenberg 775 W in terms of treatment time and specific energy at electric field strengths ranging from 20 to 45 kV/cm. Based on our results, the target microorganism for this technology in LWE varied with intensity of the PEF treatment. For electric field strengths greater than 25 kV/cm, Salmonella Enteritidis was the most PEF-resistant strain. For this Salmonella serovar the level of inactivation depended only on the specific energy applied: i.e., 106, 272, and 472 kJ/kg for 1, 2, and 3 Log(10) reductions, respectively. The developed mathematical equations based on the Weibull distribution permit estimations of maximum inactivation level of 1.9 Log(10) cycles of the target Salmonella serovar in the best-case scenario: 250 kJ/kg and 25 kV/cm. This level of inactivation indicates that PEF technology by itself cannot guarantee the security of LWE based on USDA and European regulations. The occurrence of cell damage due to PEF in the Salmonella population opens the possibility of designing combined processes enabling increased microbial lethality in LWE. 2010 Elsevier Ltd. All rights reserved.

  20. A high dynamic range pulse counting detection system for mass spectrometry.

    Science.gov (United States)

    Collings, Bruce A; Dima, Martian D; Ivosev, Gordana; Zhong, Feng

    2014-01-30

    A high dynamic range pulse counting system has been developed that demonstrates an ability to operate at up to 2e8 counts per second (cps) on a triple quadrupole mass spectrometer. Previous pulse counting detection systems have typically been limited to about 1e7 cps at the upper end of the systems dynamic range. Modifications to the detection electronics and dead time correction algorithm are described in this paper. A high gain transimpedance amplifier is employed that allows a multi-channel electron multiplier to be operated at a significantly lower bias potential than in previous pulse counting systems. The system utilises a high-energy conversion dynode, a multi-channel electron multiplier, a high gain transimpedance amplifier, non-paralysing detection electronics and a modified dead time correction algorithm. Modification of the dead time correction algorithm is necessary due to a characteristic of the pulse counting electronics. A pulse counting detection system with the capability to count at ion arrival rates of up to 2e8 cps is described. This is shown to provide a linear dynamic range of nearly five orders of magnitude for a sample of aprazolam with concentrations ranging from 0.0006970 ng/mL to 3333 ng/mL while monitoring the m/z 309.1 → m/z 205.2 transition. This represents an upward extension of the detector's linear dynamic range of about two orders of magnitude. A new high dynamic range pulse counting system has been developed demonstrating the ability to operate at up to 2e8 cps on a triple quadrupole mass spectrometer. This provides an upward extension of the detector's linear dynamic range by about two orders of magnitude over previous pulse counting systems. Copyright © 2013 John Wiley & Sons, Ltd.

  1. Autofluorescence of pigmented skin lesions using a pulsed UV laser with synchronized detection: clinical results

    DEFF Research Database (Denmark)

    Cheng, Haynes Pak Hay; Svenmarker, Pontus; Tidemand-Lichtenberg, Peter

    2010-01-01

    signal, which may in turn produce high contrast images that improve diagnosis, even in the presence of ambient room light. The synchronized set-up utilizes a compact, diode pumped, pulsed UV laser at 355 nm which is coupled to a CCD camera and a liquid crystal tunable filter. The excitation and image......We report preliminary clinical results of autofluorescence imaging of malignant and benign skin lesions, using pulsed 355 nm laser excitation with synchronized detection. The novel synchronized detection system allows high signal-to-noise ratio to be achieved in the resulting autofluorescence...

  2. On the stability of the interface between dense plasma and liquid under electrical pulse discharge in liquid medium

    International Nuclear Information System (INIS)

    Starchyk, P.D.; Porytskyy, P.V.

    2005-01-01

    It is shown that the most important influence on the plasma of electrical pulse discharges in liquid have the processes in a zone of its contact with condensed medium. The investigations of growth of corrugations are conducted which arise on an interface between both the plasma channels of electrical pulse discharges and limiting it liquid. It is shown that the growth of perturbations caused by Rayleigh-Taylor instability are nonlinearly saturated. It is established the interconnection between both the pointed perturbations and the parameters of a dense plasma of discharge channel

  3. Homogenization optics to improve detectability of a fluorescence response to a single laser pulse: Detection of feces on apples

    Science.gov (United States)

    Fecal contamination of produce is a known food safety risk. Measuring fluorescence responses to UV excitation is an established method for detecting such contamination. One measurement system utilizes a pulsed UV laser to induce a fluorescence response from fecal material and a gated intensified cam...

  4. Odors pulsed at wing beat frequencies are tracked by primary olfactory networks and enhance odor detection

    Directory of Open Access Journals (Sweden)

    Shreejoy Tripathy

    2010-03-01

    Full Text Available Each down stroke of an insect’s wings accelerates axial airflow over the antennae. Modeling studies suggest that this can greatly enhance penetration of air and air-born odorants through the antennal sensilla thereby periodically increasing odorant-receptor interactions. Do these periodic changes result in entrainment of neural responses in the antenna and antennal lobe (AL? Does this entrainment affect olfactory acuity? To address these questions, we monitored antennal and AL responses in the moth Manduca sexta while odorants were pulsed at frequencies from 10-72 Hz, encompassing the natural wingbeat frequency. Power spectral density (PSD analysis was used to identify entrainment of neural activity. Statistical analysis of PSDs indicates that the antennal nerve tracked pulsed odor up to 30 Hz. Furthermore, at least 50% of AL local field potentials (LFPs and between 7-25% of unitary spiking responses also tracked pulsed odor up to 30 Hz in a frequency-locked manner. Application of bicuculline (200µM abolished pulse tracking in both LFP and unitary responses suggesting that GABAA receptor activation is necessary for pulse tracking within the AL. Finally, psychophysical measures of odor detection establish that detection thresholds are lowered when odor is pulsed at 20 Hz. These results suggest that AL networks can respond to the oscillatory dynamics of stimuli such as those imposed by the wing beat in a manner analogous to mammalian sniffing.

  5. Detection of the Thickness Variation of a Stainless Steel sample using Pulsed Eddy Current

    International Nuclear Information System (INIS)

    Cheong, Y. M.; Angani, C. S.; Park, D. G.; Jhong, H. K.; Kim, G. D.; Kim, C. G.

    2008-01-01

    The Pulsed Eddy Current (PEC) system has been developed for the detection of thickness variation of stainless steel. The sample was machined as step configuration using stainless steel for thickness variation from 1mm to 5mm step by step. The LabView computer program was developed to display the variation in the amplitude of the detected pulse by scanning the PECT probe on the flat side of the sample. The pickup Sensor measures the effective magnetic field on the sample, which is the sum of the incident field and the field reflected by the specimen due to the induced eddy currents in the sample. We use the hall sensor for the detection. Usage of hall sensor instead of coil as a field detector improves the detectability and special resolution. This technology can be used in detection of local wall thinning of the pipeline of nuclear power plant

  6. Thermal pulse detection of photons and charged particles

    International Nuclear Information System (INIS)

    Riisager, K.; Hansen, P.G.

    1986-01-01

    During the last few years the technique of thermal detection has been developed so that high resolution spectroscopy of single particles is possible. This method seems to yield improvements in energy resolution of about a factor 100 and could thus be of decisive importance for neutrino experiments. The theoretical limits for the resolution and the experimental works performed to data are reviewed and the Goeteborg detector is briefly described. 18 refs

  7. Energy-efficient biomass processing with pulsed electric fields for bioeconomy and sustainable development.

    Science.gov (United States)

    Golberg, Alexander; Sack, Martin; Teissie, Justin; Pataro, Gianpiero; Pliquett, Uwe; Saulis, Gintautas; Stefan, Töpfl; Miklavcic, Damijan; Vorobiev, Eugene; Frey, Wolfgang

    2016-01-01

    Fossil resources-free sustainable development can be achieved through a transition to bioeconomy, an economy based on sustainable biomass-derived food, feed, chemicals, materials, and fuels. However, the transition to bioeconomy requires development of new energy-efficient technologies and processes to manipulate biomass feed stocks and their conversion into useful products, a collective term for which is biorefinery. One of the technological platforms that will enable various pathways of biomass conversion is based on pulsed electric fields applications (PEF). Energy efficiency of PEF treatment is achieved by specific increase of cell membrane permeability, a phenomenon known as membrane electroporation. Here, we review the opportunities that PEF and electroporation provide for the development of sustainable biorefineries. We describe the use of PEF treatment in biomass engineering, drying, deconstruction, extraction of phytochemicals, improvement of fermentations, and biogas production. These applications show the potential of PEF and consequent membrane electroporation to enable the bioeconomy and sustainable development.

  8. Effect of pulsed electric fields treatment and mash size on extraction and composition of apple juices.

    Science.gov (United States)

    Turk, Mohammad F; Baron, Alain; Vorobiev, Eugene

    2010-09-08

    This study explored the effect of pulsed electric field (PEF) treatment (E=450 V/cm; tt=10 ms; Eapple mash size on juice yield, polyphenolic compounds, sugars, and malic acid. Juice yield increased significantly after PEF treatment of large mash (Y=71.4%) and remained higher than the juice yield obtained for a control small mash (45.6%). The acid sweet balance was not altered by PEF. A correlation was established between the decrease of light absorbance (control: 1.43; treated: 1.10) and the decline of native polyphenols yield due to PEF treatment (control: 9.6%; treated: 5.9% for small mash). An enhanced oxidation of phenolic compounds in cells due to electroporation of the inner cell membrane and the adsorption of the oxidized products on the mash may explain both the lower light absorbance and the lower native polyphenol concentration.

  9. Further study on heredity of liquid aluminum modified by electric pulse

    Directory of Open Access Journals (Sweden)

    Qi Jingang

    2011-08-01

    Full Text Available The remarkable heredity of liquid aluminum modified by electric pulse (EP, EPM has been uncovered. For better understanding from all aspects on the hereditary properties, the present research deals with the heredity destruction and the secondary EPM procedure. It is shown that the secondary EPM is capable of preventing the heredity reduction of EP-modified liquid aluminum, and that the final refining effect has a close relationship with technique parameters of the secondary EPM. Furthermore, at a certain superheated temperature depending on the initial EPM technique parameters, the heredity relationship of EP-modified liquid aluminum can be cut off during remelting. High temperature X-ray diffraction combining with the DSC tests also indicates that the EP-induced structure changes have almost disappeared at an elevated remelting temperature.

  10. Experimental characterization of plasma formation and shockwave propagation induced by high power pulsed underwater electrical discharge.

    Science.gov (United States)

    Claverie, A; Deroy, J; Boustie, M; Avrillaud, G; Chuvatin, A; Mazanchenko, E; Demol, G; Dramane, B

    2014-06-01

    High power pulsed electrical discharges into liquids are investigated for new industrial applications based on the efficiency of controlled shock waves. We present here new experimental data obtained by combination of detailed high speed imaging equipments. It allows the visualization of the very first instants of plasma discharge formation, and then the pulsations of the gaseous bubble with an accurate timing of events. The time history of the expansion/compression of this bubble leads to an estimation of the energy effectively transferred to water during the discharge. Finally, the consecutive shock generation driven by this pulsating bubble is optically monitored by shadowgraphs and schlieren setup. These data provide essential information about the geometrical pattern and chronometry associated with the shock wave generation and propagation.

  11. Pulsed electric field-assisted modification of pectin from sugar beet pulp.

    Science.gov (United States)

    Ma, Sen; Wang, Zhong-he

    2013-02-15

    This current work is concerned with the modification of sugar beet pulp (SBP) pectin assisted by pulsed electric filed (PEF) without solvent. Pectin-arachates with degree of esterification (DE) ranging from 49 to 84 were prepared in one-step modification. The results showed that the DE of pectin derivatives increased significantly with the PEF intensity from 18 to 30 kV cm((1) and total specific energy input from 124 to 345 J mL((1). Evidence of modification of pectin was provided by FT-IR, X-ray diffraction patterns and NMR spectra. Thermogravimetric investigation of modified pectin indicated a higher thermal stability than the untreated one. Results revealed that PEF technology is a promising method for industrial manufacture of pectin derivatives. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Enhanced methane production from pig slurry with pulsed electric field pre-treatment.

    Science.gov (United States)

    Safavi, Seyedeh Masoumeh; Unnthorsson, Runar

    2018-02-01

    Intensive amount of manure produced in pig breeding sectors represents negative impact on the environment and requires optimal management. Anaerobic digestion as a well-known manure management process was optimized in this experimental study by pulsed electric field (PEF) pre-treatment. The effect of PEF on methane production was investigated at three different intensities (15, 30 and 50 kWh/m 3 ). The results indicate that the methane production and chemical oxygen demand (COD) removal was improved by continuous escalation of applied intensity, up to 50 kWh/m 3 . In comparison with untreated slurry, methane production and COD removal were increased up to 58% and 44%, respectively.

  13. Environmental temperature affects physiology and survival of nanosecond pulsed electric field-treated cells.

    Science.gov (United States)

    Yin, Shengyong; Miao, Xudong; Zhang, Xueming; Chen, Xinhua; Wen, Hao

    2018-02-01

    Nanosecond pulsed electric field (nsPEF) is a novel non-thermal tumor ablation technique. However, how nsPEF affect cell physiology at different environmental temperature is still kept unknown. But this issue is of critical clinical practice relevance. This work aim to investigate how nsPEF treated cancer cells react to different environmental temperatures (0, 4, 25, and 37°C). Their cell viability, apoptosis, mitochondrial membrane potential, and reactive oxygen species (ROS) were examined. Lower temperature resulted in higher apoptosis rate, decreased mitochondria membrane potential, and increased ROS levels. Sucrose and N-acetylcysteine (NAC) pre-incubation inhibit ROS generation and increase cell survival, protecting nsPEF-treated cells from low temperature-caused cell death. This work provides an experimental basis for hypothermia and fluid transfusion during nsPEF ablation with anesthesia. © 2017 Wiley Periodicals, Inc.

  14. Cell wall as a target for bacteria inactivation by pulsed electric fields

    Science.gov (United States)

    Pillet, Flavien; Formosa-Dague, Cécile; Baaziz, Houda; Dague, Etienne; Rols, Marie-Pierre

    2016-01-01

    The integrity and morphology of bacteria is sustained by the cell wall, the target of the main microbial inactivation processes. One promising approach to inactivation is based on the use of pulsed electric fields (PEF). The current dogma is that irreversible cell membrane electro-permeabilisation causes the death of the bacteria. However, the actual effect on the cell-wall architecture has been poorly explored. Here we combine atomic force microscopy and electron microscopy to study the cell-wall organization of living Bacillus pumilus bacteria at the nanoscale. For vegetative bacteria, exposure to PEF led to structural disorganization correlated with morphological and mechanical alterations of the cell wall. For spores, PEF exposure led to the partial destruction of coat protein nanostructures, associated with internal alterations of cortex and core. Our findings reveal for the first time that the cell wall and coat architecture are directly involved in the electro-eradication of bacteria. PMID:26830154

  15. Influence of pulsed electric field on enzymes, bacteria and volatile flavor compounds of unpasteurized sake

    Science.gov (United States)

    Takamasa, OKUMURA; Taro, YAEGASHI; Takahiro, FUJIWARA; Katsuyuki, TAKAHASHI; Koichi, TAKAKI; Tomo, KUDO

    2018-04-01

    A pulsed electric field (PEF) was applied to unpasteurized sake at constant temperatures, at which α-amylase was not inactivated. We adjusted the input energy to be identical for the temperatures by changing the number of PEF application, because the current significantly increased with the temperature, even the amplitude of the applied voltage was identical. As a result, the α-amylase was seemed to be inactivated by PEF application, not due to thermal effect. The glucoamylase was significantly inactivated by PEF. Moreover, the acid carboxypeptidase was inactivated by PEF at 4 °C but significantly activated at 25 °C. These results show that the sensitivity of enzyme to PEF application differs depending on the types of enzyme and treatment temperature. On the other hand, the colony number of bacteria was remarkably decreased, but the amount of the volatile flavor compounds was not decreased by PEF application.

  16. Separation and collection of coarse aggregate from waste concrete by electric pulsed power

    Science.gov (United States)

    Shigeishi, Mitsuhiro

    2017-09-01

    Waste concrete accounts for a substantial fraction of construction waste, and the recycling of waste concrete as concrete aggregate for construction is an important challenge associated with the rapid increase in the amount of waste concrete and the tight supply of natural aggregate. In this study, we propose a technique based on the use of high-voltage pulsed electric discharge into concrete underwater for separating and collecting aggregate from waste concrete with minimal deterioration of quality. By using this technique, the quality of the coarse aggregate separated and collected from concrete test specimens is comparable to that of coarse aggregate recycled by heating and grinding methods, thus satisfying the criteria in Japan Industrial Standard (JIS) A 5021 for the oven-dry density and the water absorption of coarse aggregate by advanced recycling.

  17. Permeabilization of the nuclear envelope following nanosecond pulsed electric field exposure

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Gary L., E-mail: gary.l.thompson.3@gmail.com [Oak Ridge Institute for Science & Education, Joint Base San Antonio Fort Sam Houston, TX, 78234 (United States); Roth, Caleb C. [Department of Radiological Sciences, University of Texas Health Science Center at San Antonio, TX, 78234 (United States); Kuipers, Marjorie A. [Radio Frequency Radiation Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio Fort Sam Houston, TX, 78234 (United States); Tolstykh, Gleb P. [General Dynamics IT, Joint Base San Antonio Fort Sam Houston, TX, 78234 (United States); Beier, Hope T. [Optical Radiation Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio Fort Sam Houston, TX, 78234 (United States); Ibey, Bennett L. [Radio Frequency Radiation Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio Fort Sam Houston, TX, 78234 (United States)

    2016-01-29

    Permeabilization of cell membranes occurs upon exposure to a threshold absorbed dose (AD) of nanosecond pulsed electric fields (nsPEF). The ultimate, physiological bioeffect of this exposure depends on the type of cultured cell and environment, indicating that cell-specific pathways and structures are stimulated. Here we investigate 10 and 600 ns duration PEF effects on Chinese hamster ovary (CHO) cell nuclei, where our hypothesis is that pulse disruption of the nuclear envelope membrane leads to observed cell death and decreased viability 24 h post-exposure. To observe short-term responses to nsPEF exposure, CHO cells have been stably transfected with two fluorescently-labeled proteins known to be sequestered for cellular chromosomal function within the nucleus – histone-2b (H2B) and proliferating cell nuclear antigen (PCNA). H2B remains associated with chromatin after nsPEF exposure, whereas PCNA leaks out of nuclei permeabilized by a threshold AD of 10 and 600 ns PEF. A downturn in 24 h viability, measured by MTT assay, is observed at the number of pulses required to induce permeabilization of the nucleus. - Highlights: • The ability of nsPEF to damage nuclear structures within cells is investigated. • Leakage of proliferating nuclear antigen from nuclei is induced by nsPEF. • High doses of nsPEF disrupt cortical lamin and cause chromatin decompaction. • Histone H2B remains attached to chromatin following nsPEF exposure. • DNA does not leak out of nsPEF-permeabilized nuclei.

  18. Influence of pulsed electric field treatments on the volatile compounds of milk in comparison with pasteurized processing.

    Science.gov (United States)

    Zhang, Sha; Yang, Ruijin; Zhao, Wei; Hua, Xiao; Zhang, Wenbin; Zhang, Zhong

    2011-01-01

    Effects of pulsed electric field (PEF) treatments on the volatile profiles of milk were studied and compared with pasteurized treatment of high temperature short time (HTST) (75 °C, 15 s). Volatile compounds were extracted by solid-phase micro-extraction (SPME) and identified by gas chromatography/mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). A total of 37 volatile compounds were determined by GC-MS, and 19 volatile compounds were considered to be major contributors to the characteristic flavor of milk samples. PEF treatment resulted in an increase in aldehydes. Milk treated with PEF at 30 kV/cm showed the highest content of pentanal, hexanal, and nonanal, while heptanal and decanal contents were lower than in pasteurized milk, but higher than in raw milk. All the methyl ketones detected in PEF milk were lower than in pasteurized milk. No significant differences in acids (acetic acid, butanoic acid, hexanoic acid, octanoic acid, and decanoic acid), lactones, and alcohols were observed between pasteurized and PEF-treated samples; however, 2(5H)-furanone was only detected in PEF-treated milk. Although GC-MS results showed that there were some volatile differences between pasteurized and PEF-treated milk, GC-O data showed no significant difference between the 2 samples.

  19. Transmission electron microscopy of Listeria innocua treated by pulsed electric fields and nisin in skimmed milk.

    Science.gov (United States)

    Calderón-Miranda, M L; Barbosa-Cánovas, G V; Swanson, B G

    1999-10-01

    Pulsed electric fields (PEF) is a nonthermal food preservation process where organoleptic and nutritional properties of the food are maintained. PEF is known to inactivate microorganisms by causing dielectric breakdown of the cell membrane, thus altering the functionality of the membrane as a semipermeable barrier. The extent of damage of the cell membrane, whether visible in the form of a pore or as loss of membrane functionality leads to the inactivation of the microorganism. The objective of this study was to investigate under transmission electron microscopy (TEM) the morphological changes on Listerit innocua as a result of PEF treatment in skimmed milk containing nisin. L. innocua was subjected to PEF at selected electric field intensities of 30, 40, and 50 kV/cm. L. innocua was treated by PEF in both skimmed milk with and without 37 IU nisin/ml. L. innocua treated by PEF in skimmed milk exhibited an increase in the cell wall roughness. cytoplasmic clumping, leakage of cellular material, and rupture of the cell walls and cell membranes. L. innocua subjected to PEF in skimmed milk containing 37 IU nisin/ml exhibited an increased cell wall width. At the highest electric field intensity, 50 kV/cm, elongation of the cell length was observed. There were no morphological differences between cells treated by PEF in skimmed milk with or without nisin. The combination of PEF and nisin exhibit an additive effect in the morphological damage observed on L. innocua. Pore formation was observed on L. innocua for an electric field intensity of 40 kV/cm. The inactivation of L. innocua was a consequence of rupture of the cell membrane and loss of cell membrane functionality.

  20. Producing nitric oxide by pulsed electrical discharge in air for portable inhalation therapy.

    Science.gov (United States)

    Yu, Binglan; Muenster, Stefan; Blaesi, Aron H; Bloch, Donald B; Zapol, Warren M

    2015-07-01

    Inhalation of nitric oxide (NO) produces selective pulmonary vasodilation and is an effective therapy for treating pulmonary hypertension in adults and children. In the United States, the average cost of 5 days of inhaled NO for persistent pulmonary hypertension of the newborn is about $14,000. NO therapy involves gas cylinders and distribution, a complex delivery device, gas monitoring and calibration equipment, and a trained respiratory therapy staff. The objective of this study was to develop a lightweight, portable device to serve as a simple and economical method of producing pure NO from air for bedside or portable use. Two NO generators were designed and tested: an offline NO generator and an inline NO generator placed directly within the inspiratory line. Both generators use pulsed electrical discharges to produce therapeutic range NO (5 to 80 parts per million) at gas flow rates of 0.5 to 5 liters/min. NO was produced from air, as well as gas mixtures containing up to 90% O2 and 10% N2. Potentially toxic gases produced in the plasma, including nitrogen dioxide (NO2) and ozone (O3), were removed using a calcium hydroxide scavenger. An iridium spark electrode produced the lowest ratio of NO2/NO. In lambs with acute pulmonary hypertension, breathing electrically generated NO produced pulmonary vasodilation and reduced pulmonary arterial pressure and pulmonary vascular resistance index. In conclusion, electrical plasma NO generation produces therapeutic levels of NO from air. After scavenging to remove NO2 and O3 and filtration to remove particles, electrically produced NO can provide safe and effective treatment of pulmonary hypertension. Copyright © 2015, American Association for the Advancement of Science.

  1. Unexpected ICD pulse generator failure due to electronic circuit damage caused by electrical overstress.

    Science.gov (United States)

    Hauser, R G; Hayes, D L; Almquist, A K; Epstein, A E; Parsonnet, V; Tyers, G F; Vlay, S C; Schoenfeld, M H

    2001-07-01

    Because it is a lifesaving device, the unexpected failure of an ICD can be catastrophic. We report ICD electronic circuit failure due to electrical overstress damage (EOS) to the high voltage hybird circuit and other electronic components in a series of ICD pulse generator models. Data were obtained from the Multicenter Registry of Pacemaker and ICD Pacemaker and Lead Failures, and from the manufactures' adverse event reports, that were in the FDA's Manufacturer and User Facility Device Experience (MAUDE) database. Of 16 nonbattery Guidant/CPI ICD pulse generator failures reported to the registry, 6 (38%) have been confirmed by the manufacturer to be EOS related, and Guidant/CPI has reported 273 such failures to the FDA as of 12/29/00. The signs of failure included loss of telemetry and inability to deliver therapy, and some patients have experienced serious adverse events. Hybrid circuit damage may have occurred during capacitor charging or reform, and the majority appears to have happened during normal ICD function. While the incidence of this problem is unknown, a management strategy should be adopted that includes routine follow-up every 3 months and device evaluation after a shock or exposure to external defibrillation or electrosurgical devices. This study suggests that additional data are needed to determine the incidence of this problem, and that our present methods for monitoring the performance of ICD's following market release are inadequate.

  2. Osmotic dehydration of organic kiwifruit pre-treated by pulsed electric fields and monitored by NMR.

    Science.gov (United States)

    Traffano-Schiffo, Maria Victoria; Laghi, Luca; Castro-Giraldez, Marta; Tylewicz, Urszula; Rocculi, Pietro; Ragni, Luigi; Dalla Rosa, Marco; Fito, Pedro J

    2017-12-01

    Osmotic dehydration (OD) is a widely used preservation technique that consists in the reduction in food water activity by the immersion of the biological tissue in hypertonic solutions. The aim of this work was to analyze the effect of pulsed electric fields (PEF) in mass transfer as a pre-treatment of the OD using NMR. In this sense, PEF pre-treatments were done using three different voltages (100, 250 and 400V/cm) and 60 number of pulse. The OD of kiwifruit was carried out in 61.5% of sucrose solution at 25°C, for a contact period from 0 to 120min. The water distribution into the cellular tissue was studied by NMR relaxometry. In conclusion, NMR is an excellent technique for quantifying water molecules according to their interactions in the fruit tissue, obtaining the adsorbed water and opening the possibility to apply the BET model to fit the adsorbed isotherm over the whole range of water activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Inactivation of Ricin Toxin by Nanosecond Pulsed Electric Fields Including Evidences from Cell and Animal Toxicity

    Science.gov (United States)

    Wei, Kai; Li, Wei; Gao, Shan; Ji, Bin; Zang, Yating; Su, Bo; Wang, Kaile; Yao, Maosheng; Zhang, Jue; Wang, Jinglin

    2016-01-01

    Ricin is one of the most toxic and easily produced plant protein toxin extracted from the castor oil plant, and it has been classified as a chemical warfare agent. Here, nanosecond pulsed electric fields (nsPEFs) at 30 kV/cm (pulse durations: 10 ns, 100 ns, and 300 ns) were applied to inactivating ricin up to 4.2 μg/mL. To investigate the efficacy, cells and mice were tested against the ricin treated by the nsPEFs via direct intraperitoneal injection and inhalation exposure. Results showed that nsPEFs treatments can effectively reduce the toxicity of the ricin. Without the nsPEFs treatment, 100% of mice were killed upon the 4 μg ricin injection on the first day, however 40% of the mice survived the ricin treated by the nsPEFs. Compared to injection, inhalation exposure even with higher ricin dose required longer time to observe mice fatality. Pathological observations revealed damages to heart, lung, kidney, and stomach after the ricin exposure, more pronounced for lung and kidney including severe bleeding. Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) and circular dichroism (CD) analyses revealed that although the primary structure of ricin was not altered, its secondary structures (beta-sheet and beta-turn) underwent transition upon the nsPEFs treatment. PMID:26728251

  4. Disassembly of actin structures by nanosecond pulsed electric field is a downstream effect of cell swelling.

    Science.gov (United States)

    Pakhomov, Andrei G; Xiao, Shu; Pakhomova, Olga N; Semenov, Iurii; Kuipers, Marjorie A; Ibey, Bennett L

    2014-12-01

    Disruption of the actin cytoskeleton structures was reported as one of the characteristic effects of nanosecond-duration pulsed electric field (nsPEF) in both mammalian and plant cells. We utilized CHO cells that expressed the monomeric fluorescent protein (mApple) tagged to actin to test if nsPEF modifies the cell actin directly or as a consequence of cell membrane permeabilization. A train of four 600-ns pulses at 19.2 kV/cm (2 Hz) caused immediate cell membrane poration manifested by YO-PRO-1 dye uptake, gradual cell rounding and swelling. Concurrently, bright actin features were replaced by dimmer and uniform fluorescence of diffuse actin. To block the nsPEF-induced swelling, the bath buffer was isoosmotically supplemented with an electropore-impermeable solute (sucrose). A similar addition of a smaller, electropore-permeable solute (adonitol) served as a control. We demonstrated that sucrose efficiently blocked disassembly of actin features by nsPEF, whereas adonitol did not. Sucrose also attenuated bleaching of mApple-tagged actin in nsPEF-treated cells (as integrated over the cell volume), although did not fully prevent it. We conclude that disintegration of the actin cytoskeleton was a result of cell swelling, which, in turn, was caused by cell permeabilization by nsPEF and transmembrane diffusion of solutes which led to the osmotic imbalance. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Current and future prospects for the use of pulsed electric field in the meat industry.

    Science.gov (United States)

    Bhat, Zuhaib F; Morton, James D; Mason, Susan L; Bekhit, Alaa El-Din A

    2018-02-02

    Pulsed electric field (PEF) is a novel non-thermal technology that has recently attracted the attention of meat scientists and technologists due to its ability to modify membrane structure and enhance mass transfer. Several studies have confirmed the potential of pulsed electric field for improving meat tenderness in both pre-rigor and post-rigor muscles during aging. However, there is a high degree of variability between studies and the underlying mechanisms are not clearly understood. While some studies have suggested physical disruption as the main cause of PEF induced tenderness, enzymatic nature of the tenderization seems to be the most plausible mechanism. Several studies have suggested the potential of PEF to mediate the tenderization process due to its membrane altering properties causing early release of calcium ions and early activation of the calpain proteases. However, experimental research is yet to confirm this postulation. Recent studies have also reported increased post-mortem proteolysis in PEF treated muscles during aging. PEF has also been reported to accelerate curing, enhance drying and reduce the numbers of both pathogens and spoilage organisms in meat, although that demands intense processing conditions. While tenderization, meat safety and accelerated curing appears to be the areas where PEF could provide attractive options in meat processing, further research is required before the application of PEF becomes a commercial reality in the meat industry. It needs to deal with carcasses which vary biochemically and in composition (muscle, fat, and bones). This review critically evaluates the published reports on the topic with the aim of reaching a clear understanding of the possible applications of PEF in the meat sector in addition to providing some insight on critical issues that need to be addressed for the technology to be a practical option for the meat industry.

  6. Detection and Characterization of Flaws in Sprayed on Foam Insulation with Pulsed Terahertz Frequency Electromagnetic Waves

    Science.gov (United States)

    Winfree, William P.; Madaras, Eric I.

    2005-01-01

    The detection and repair of flaws such as voids and delaminations in the sprayed on foam insulation of the external tank reduces the probability of foam debris during shuttle ascent. The low density of sprayed on foam insulation along with it other physical properties makes detection of flaws difficult with conventional techniques. An emerging technology that has application for quantitative evaluation of flaws in the foam is pulsed electromagnetic waves at terahertz frequencies. The short wavelengths of these terahertz pulses make them ideal for imaging flaws in the foam. This paper examines the application of terahertz pulses for flaw detection in foam characteristic of the foam insulation of the external tank. Of particular interest is the detection of voids and delaminations, encapsulated in the foam or at the interface between the foam and a metal backing. The technique is shown to be capable of imaging small voids and delaminations through as much as 20 cm of foam. Methods for reducing the temporal responses of the terahertz pulses to improve flaw detection and yield quantitative characterizations of the size and location of the flaws are discussed.

  7. Drone Detection with Chirp‐Pulse Radar Based on Target Fluctuation Models

    Directory of Open Access Journals (Sweden)

    Byung‐Kwan Kim

    2018-04-01

    Full Text Available This paper presents a pulse radar system to detect drones based on a target fluctuation model, specifically the Swerling target model. Because drones are small atypical objects and are mainly composed of non‐conducting materials, their radar cross‐section value is low and fluctuating. Therefore, determining the target fluctuation model and applying a proper integration method are important. The proposed system is herein experimentally verified and the results are discussed. A prototype design of the pulse radar system is based on radar equations. It adopts three different pulse modes and a coherent pulse integration to ensure a high signal‐to‐noise ratio. Outdoor measurements are performed with a prototype radar system to detect Doppler frequencies from both the drone frame and blades. The results indicate that the drone frame and blades are detected within an instrumental maximum range. Additionally, the results show that the drone's frame and blades are close to the Swerling 3 and 4 target models, respectively. By the analysis of the Swerling target models, proper integration methods for detecting drones are verified and can thus contribute to increasing in detectability.

  8. Practical photon number detection with electric field-modulated silicon avalanche photodiodes.

    Science.gov (United States)

    Thomas, O; Yuan, Z L; Shields, A J

    2012-01-24

    Low-noise single-photon detection is a prerequisite for quantum information processing using photonic qubits. In particular, detectors that are able to accurately resolve the number of photons in an incident light pulse will find application in functions such as quantum teleportation and linear optics quantum computing. More generally, such a detector will allow the advantages of quantum light detection to be extended to stronger optical signals, permitting optical measurements limited only by fluctuations in the photon number of the source. Here we demonstrate a practical high-speed device, which allows the signals arising from multiple photon-induced avalanches to be precisely discriminated. We use a type of silicon avalanche photodiode in which the lateral electric field profile is strongly modulated in order to realize a spatially multiplexed detector. Clearly discerned multiphoton signals are obtained by applying sub-nanosecond voltage gates in order to restrict the detector current.

  9. Impact of pulsed-electric field and high-voltage electrical discharges on red wine microbial stabilization and quality characteristics.

    Science.gov (United States)

    Delsart, C; Grimi, N; Boussetta, N; Miot Sertier, C; Ghidossi, R; Vorobiev, E; Mietton Peuchot, M

    2016-01-01

    In this study, pulsed-electric fields (PEF) and high-voltage electrical discharges (HVED) are proposed as new techniques for the microbial stabilization of red wines before bottling. The efficiency of the treatment was then evaluated. PEF and HVED-treatments have been applied to wine for the inactivation of Oenococcus oeni CRBO 9304, O. oeni CRBO 0608, Pediococcus parvulus CRBO 2.6 and Brettanomyces bruxellensis CB28. Different treatment times (1, 2, 4, 6, 8 and 10 ms) were used at 20 kV cm(-1) for the PEF treatments and at 40 kV for the HVED treatments, which correspond to applied energies from 80 to 800 kJ l(-1) . The effects of the treatments on the microbial inactivation rate and on various characteristics of red wines (phenolic composition, chromatic characteristics and physico-chemical parameters) were measured. The application of PEF or HVED treatments on red wine allowed the inactivation of alteration yeasts (B. bruxellensis CB28) and bacteria (O. oeni CRBO 9304, O. oeni CRBO 0608 and P. parvulus CRBO 2.6). The electric discharges at 40 kV were less effective than the PEF even after 10 ms of treatments. Indeed, 4 ms of PEF treatment at 20 kV cm(-1) were sufficient to inactivate all micro-organisms present in the wines. Also, the use of PEF had no negative impact on the composition of wines compared to the HVED treatments. Contrary to PEF, the phenolics compounds were degraded after the HVED treatment and the physico-chemical composition of wine were modified with HVED. PEF technology seems to be an interesting alternative to stabilize microbiologically wines before bottling and without modifying their composition. This process offers many advantages for winemakers: no chemical inputs, low energy consumption (320 kJ l(-1) ), fast (treatment time of 4 ms) and athermal (ΔT ≈ 10°C). © 2015 The Society for Applied Microbiology.

  10. Digital coherent detection research on Brillouin optical time domain reflectometry with simplex pulse codes

    International Nuclear Information System (INIS)

    Hao Yun-Qi; Ye Qing; Pan Zheng-Qing; Cai Hai-Wen; Qu Rong-Hui

    2014-01-01

    The digital coherent detection technique has been investigated without any frequency-scanning device in the Brillouin optical time domain reflectometry (BOTDR), where the simplex pulse codes are applied in the sensing system. The time domain signal of every code sequence is collected by the data acquisition card (DAQ). A shift-averaging technique is applied in the frequency domain for the reason that the local oscillator (LO) in the coherent detection is fix-frequency deviated from the primary source. With the 31-bit simplex code, the signal-to-noise ratio (SNR) has 3.5-dB enhancement with the same single pulse traces, accordant with the theoretical analysis. The frequency fluctuation for simplex codes is 14.01 MHz less than that for a single pulse as to 4-m spatial resolution. The results are believed to be beneficial for the BOTDR performance improvement. (general)

  11. Using hydrocarbon as a carbon source for synthesis of carbon nanotube by electric field induced needle-pulsed plasma

    International Nuclear Information System (INIS)

    Kazemi Kia, Kaveh; Bonabi, Fahimeh

    2013-01-01

    In this work different hydrocarbons are used as the carbon source, in the production of carbon nanotubes (CNTs) and nano onions. An electric field induced needle pulse arc-discharge reactor is used. The influence of starting carbon on the synthesis of CNTs is investigated. The production efficiency is compared for Acetone, Isopropanol and Naphthalene as simple hydrocarbons. The hydrocarbons are preheated and then pretreated by electric field before being exposed to plasma. The hydrocarbon vapor is injected into plasma through a graphite spout in the cathode assembly. The pulsed plasma takes place between two graphite rods while a strong electric field has been already established alongside the electrodes. The pulse width is 0.3 μs. Mechanism of precursor decomposition is discussed by describing three forms of energy that are utilized to disintegrate the precursor molecules: thermal energy, electric field and kinetic energy of plasma. Molecular polarity of a hydrocarbon is one of the reasons for choosing carbon raw material as a precursor in an electric field induced low power pulsed-plasma. The results show that in order to obtain high quality carbon nanotubes, Acetone is preferred to Isopropanol and Naphthalene. Scanning probe microscopy techniques are used to investigate the products. - Highlights: • We synthesized CNTs (carbon nano tubes) by needle pulsed plasma. • We use different hydrocarbons as carbon source in the production of CNTs. • We investigated the influence of starting carbon on the synthesis of CNTs. • Thermal energy, electric field and kinetic energy are used to break carbon bonds. • Polar hydrocarbon molecules are more efficient than nonpolar ones in production

  12. Magnetogastrographic detection of gastric electrical response activity in humans

    International Nuclear Information System (INIS)

    Irimia, Andrei; Richards, William O; Bradshaw, L Alan

    2006-01-01

    The detection and characterization of gastric electrical activity has important clinical applications, including the early diagnosis of gastric diseases in humans. In mammals, this phenomenon has two important features: an electrical control activity (ECA) that manifests itself as an electric slow wave (with a frequency of 3 cycles per minute in humans) and an electrical response activity (ERA) that is characterized by spiking potentials during the plateau phase of the ECA. Whereas the ECA has been recorded in humans both invasively and non-invasively (magnetogastrography-MGG), the ERA has never been detected non-invasively in humans before. In this paper, we report on our progress towards the non-invasive detection of ERA from the human stomach using a procedure that involves the application of principal component analysis to MGG recordings, which were acquired in our case from ten normal human patients using a Superconducting QUantum Interference Device (SQUID) magnetometer. Both pre- and post-prandial recordings were acquired for each patient and 20 min of recordings (10 min of pre-prandial and 10 min of post-prandial data) were analysed for each patient. The mean percentage of ECA slow waves that were found to exhibit spikes of suspected ERA origin was 41% and 61% for pre- and post-prandial recordings, respectively, implying a 47% ERA increase post-prandially (P < 0.0001 at a 95% confidence level). The detection of ERA in humans is highly encouraging and points to the possible use of non-invasive ERA recordings as a valuable tool for the study of human gastric disorders

  13. The change of electric potentials in the oral cavity after application of extremely low frequency pulsed magnetic field

    Directory of Open Access Journals (Sweden)

    Piotr Skomro

    2012-12-01

    Full Text Available Electric potentials occurring in the oral cavity deserve attention as they may cause various diseases and subjective feelings, which are very difficult to treat. The aim of this study was to evaluate the electric potentials within the oral cavity in patients with metal fillings and metal prosthetic restorations, after using a pulsed electromagnetic field. The study was carried out on 84 patients. The Viofor JPS Classic device was used in the treatment. It generates a pulsed electromagnetic field with low induction of the extremely low frequency (ELF range. Average values of electric potentials in the preliminary test were about the same in both groups; they were 148.8 mV and 145.5 mV. After another appliance of ELF fields there was found a steady decline in the average value of electric potentials in the study group. This decrease was statistically highly significant, while mean values of electric potentials in the control group were characterized by a slightly upward tendency. The obtained statistically significant reduction of electric potentials in the oral cavity of patients having metal fillings and metal prosthetic restorations, after application of the Viofor JPS Classic device, implies a huge impact of ELF pulsed electromagnetic field on inhibition of electrochemical processes, as well as on inhibition of dental alloy corrosion. 

  14. Electrical detection of single magnetic skyrmion at room temperature

    Directory of Open Access Journals (Sweden)

    Riccardo Tomasello

    2017-05-01

    Full Text Available This paper proposes a protocol for the electrical detection of a magnetic skyrmion via the change of the tunneling magnetoresistive (TMR signal in a three-terminal device. This approach combines alternating spin-transfer torque from both spin-filtering (due to a perpendicular polarizer and spin-Hall effect with the TMR signal. Micromagnetic simulations, used to test and verify such working principle, show that there exists a frequency region particularly suitable for this achievement. This result can be at the basis of the design of a TMR based read-out for skyrmion detection, overcoming the difficulties introduced by the thermal drift of the skyrmion once nucleated.

  15. Detection of wall thinning of carbon steel pipe covered with insulation using Pulsed Eddy Current technique

    International Nuclear Information System (INIS)

    Park, Duckgun; Kishore, M. B.; Lee, D. H.

    2013-01-01

    The test sample is a ferromagnetic carbon steel pipe having different thickness, covered with a 10 cm plastic insulation laminated by 0.4 mm Al plate to simulate the pipelines in NPPs. The PEC Probe used for the wall thinning detection consists of an excitation coil and a Hall sensor. The excitation coils in the probe is driven by a rectangular bipolar current pulse and the Hall-sensor will detects the resultant field. The Hall sensor output is considered as PEC signal. Results shows that the PEC system can detect wall thinning in an insulated pipeline of the NPPs. Local wall thinning in pipelines affects the structural integrity of industries like nuclear power plants (NPPs). In the present study a pulsed eddy current (PEC) technology to detect the wall thing of carbon steel pipe covered with insulation is developed

  16. Electrical detection of magnetization dynamics via spin rectification effects

    Energy Technology Data Exchange (ETDEWEB)

    Harder, Michael, E-mail: michael.harder@umanitoba.ca; Gui, Yongsheng, E-mail: ysgui@physics.umanitoba.ca; Hu, Can-Ming, E-mail: hu@physics.umanitoba.ca

    2016-11-23

    The purpose of this article is to review the current status of a frontier in dynamic spintronics and contemporary magnetism, in which much progress has been made in the past decade, based on the creation of a variety of micro and nanostructured devices that enable electrical detection of magnetization dynamics. The primary focus is on the physics of spin rectification effects, which are well suited for studying magnetization dynamics and spin transport in a variety of magnetic materials and spintronic devices. Intended to be intelligible to a broad audience, the paper begins with a pedagogical introduction, comparing the methods of electrical detection of charge and spin dynamics in semiconductors and magnetic materials respectively. After that it provides a comprehensive account of the theoretical study of both the angular dependence and line shape of electrically detected ferromagnetic resonance (FMR), which is summarized in a handbook format easy to be used for analysing experimental data. We then review and examine the similarity and differences of various spin rectification effects found in ferromagnetic films, magnetic bilayers and magnetic tunnel junctions, including a discussion of how to properly distinguish spin rectification from the spin pumping/inverse spin Hall effect generated voltage. After this we review the broad applications of rectification effects for studying spin waves, nonlinear dynamics, domain wall dynamics, spin current, and microwave imaging. We also discuss spin rectification in ferromagnetic semiconductors. The paper concludes with both historical and future perspectives, by summarizing and comparing three generations of FMR spectroscopy which have been developed for studying magnetization dynamics.

  17. Electropermeabilization by uni- or bipolar nanosecond electric pulses: The impact of extracellular conductivity.

    Science.gov (United States)

    Gianulis, Elena C; Casciola, Maura; Xiao, Shu; Pakhomova, Olga N; Pakhomov, Andrei G

    2018-02-01

    Cellular effects caused by nanosecond electric pulses (nsEP) can be reduced by an electric field reversal, a phenomenon known as bipolar cancellation. The reason for this cancellation effect remains unknown. We hypothesized that assisted membrane discharge is the mechanism for bipolar cancellation. CHO-K1 cells bathed in high (16.1mS/cm; HCS) or low (1.8mS/cm; LCS) conductivity solutions were exposed to either one unipolar (300-ns) or two opposite polarity (300+300-ns; bipolar) nsEP (4-40kV/cm) with increasing interpulse intervals (0.1-50μs). Time-lapse YO-PRO-1 (YP) uptake revealed enhanced membrane permeabilization in LCS compared to HCS at all tested voltages. The time-dependence of bipolar cancellation was similar in both solutions, using either identical (22kV/cm) or isoeffective nsEP treatments (12 and 32kV/cm for LCS and HCS, respectively). However, cancellation was significantly stronger in LCS when the bipolar nsEP had no, or very short (bipolar cancellation was still present with interpulse intervals as long as 50μs, beyond the time expected for membrane discharge. Our findings do not support assisted membrane discharge as the mechanism for bipolar cancellation. Instead they exemplify the sustained action of nsEP that can be reversed long after the initial stimulus. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Membrane permeabilization in relation to inactivation kinetics of Lactobacillus species due to pulsed electric fields.

    Science.gov (United States)

    Wouters, P C; Bos, A P; Ueckert, J

    2001-07-01

    Membrane permeabilization due to pulsed electric field (PEF) treatment of gram-positive Lactobacillus cells was investigated by using propidium iodide uptake and single-cell analysis with flow cytometry. Electric field strength, energy input, treatment time, and growth phase affected membrane permeabilization of Lactobacillus plantarum during PEF treatment. A correlation between PEF inactivation and membrane permeabilization of L. plantarum cells was demonstrated, whereas no relationship was observed between membrane permeabilization and heat inactivation. The same results were obtained with a Lactobacillus fermentum strain, but the latter organism was more PEF resistant and exhibited less membrane permeabilization, indicating that various bacteria have different responses to PEF treatment. While membrane permeabilization was the main factor involved in the mechanism of inactivation, the growth phase and the acidity of the environment also influenced inactivation. By using flow cytometry it was possible to sort cells in the L. plantarum population based on different cell sizes and shapes, and the results were confirmed by image analysis. An apparent effect of morphology on membrane permeabilization was observed, and larger cells were more easily permeabilized than smaller cells. In conclusion, our results indicate that the ability of PEF treatment to cause membrane permeabilization is an important factor in determining inactivation. This finding should have an effect on the final choice of the processing parameters used so that all microorganisms can be inactivated and, consequently, on the use of PEF treatment as an alternative method for preserving food products.

  19. Membrane Permeabilization in Relation to Inactivation Kinetics of Lactobacillus Species due to Pulsed Electric Fields

    Science.gov (United States)

    Wouters, Patrick C.; Bos, Ad P.; Ueckert, Joerg

    2001-01-01

    Membrane permeabilization due to pulsed electric field (PEF) treatment of gram-positive Lactobacillus cells was investigated by using propidium iodide uptake and single-cell analysis with flow cytometry. Electric field strength, energy input, treatment time, and growth phase affected membrane permeabilization of Lactobacillus plantarum during PEF treatment. A correlation between PEF inactivation and membrane permeabilization of L. plantarum cells was demonstrated, whereas no relationship was observed between membrane permeabilization and heat inactivation. The same results were obtained with a Lactobacillus fermentum strain, but the latter organism was more PEF resistant and exhibited less membrane permeabilization, indicating that various bacteria have different responses to PEF treatment. While membrane permeabilization was the main factor involved in the mechanism of inactivation, the growth phase and the acidity of the environment also influenced inactivation. By using flow cytometry it was possible to sort cells in the L. plantarum population based on different cell sizes and shapes, and the results were confirmed by image analysis. An apparent effect of morphology on membrane permeabilization was observed, and larger cells were more easily permeabilized than smaller cells. In conclusion, our results indicate that the ability of PEF treatment to cause membrane permeabilization is an important factor in determining inactivation. This finding should have an effect on the final choice of the processing parameters used so that all microorganisms can be inactivated and, consequently, on the use of PEF treatment as an alternative method for preserving food products. PMID:11425727

  20. Effects of Pulsed Electric Field (PEF) Treatment on Enhancing Activity and Conformation of α-Amylase.

    Science.gov (United States)

    Tian, Mei-ling; Fang, Ting; Du, Mu-ying; Zhang, Fu-sheng

    2016-04-01

    To explore an efficient, safe, and speedy application of pulsed electric field (PEF) technology for enzymatic modification, effects of PEF treatment on the enzymatic activity, property and kinetic parameters of α-amylase were investigated. Conformational transitions were also studied with the aid of circular dichroism (CD) and fluorescence spectra. The maximum enzymatic activity of α-amylase was obtained under 15 kV/cm electric field intensity and 100 mL/min flow velocity PEF treatment, in which the enzymatic activity increased by 22.13 ± 1.14% compared with control. The activation effect could last for 18 h at 4 °C. PEF treatment could widen the range of optimum temperature for α-amylase, however, it barely exerted any effect on the optimum pH. On the other hand, α-amylase treated by PEF showed an increase of Vmax, t1/2 and ΔG, whereas a decrease of Km and k were observed. Furthermore, it can be observed from fluorescence and CD spectra that PEF treatment had increased the number of amino acid residues, especially that of tryptophan, on α-amylase surface with enhanced α-helices by 34.76% and decreased random coil by 12.04% on α-amylase when compared with that of untreated. These changes in structure had positive effect on enhancing α-amylase activity and property.

  1. Characterization of Pressure Transients Generated by Nanosecond Electrical Pulse (nsEP) Exposure

    Science.gov (United States)

    Roth, Caleb C.; Barnes Jr., Ronald A.; Ibey, Bennett L.; Beier, Hope T.; Christopher Mimun, L.; Maswadi, Saher M.; Shadaram, Mehdi; Glickman, Randolph D.

    2015-01-01

    The mechanism(s) responsible for the breakdown (nanoporation) of cell plasma membranes after nanosecond pulse (nsEP) exposure remains poorly understood. Current theories focus exclusively on the electrical field, citing electrostriction, water dipole alignment and/or electrodeformation as the primary mechanisms for pore formation. However, the delivery of a high-voltage nsEP to cells by tungsten electrodes creates a multitude of biophysical phenomena, including electrohydraulic cavitation, electrochemical interactions, thermoelastic expansion, and others. To date, very limited research has investigated non-electric phenomena occurring during nsEP exposures and their potential effect on cell nanoporation. Of primary interest is the production of acoustic shock waves during nsEP exposure, as it is known that acoustic shock waves can cause membrane poration (sonoporation). Based on these observations, our group characterized the acoustic pressure transients generated by nsEP and determined if such transients played any role in nanoporation. In this paper, we show that nsEP exposures, equivalent to those used in cellular studies, are capable of generating high-frequency (2.5 MHz), high-intensity (>13 kPa) pressure transients. Using confocal microscopy to measure cell uptake of YO-PRO®-1 (indicator of nanoporation of the plasma membrane) and changing the electrode geometry, we determined that acoustic waves alone are not responsible for poration of the membrane. PMID:26450165

  2. Characterization of Pressure Transients Generated by Nanosecond Electrical Pulse (nsEP) Exposure.

    Science.gov (United States)

    Roth, Caleb C; Barnes, Ronald A; Ibey, Bennett L; Beier, Hope T; Christopher Mimun, L; Maswadi, Saher M; Shadaram, Mehdi; Glickman, Randolph D

    2015-10-09

    The mechanism(s) responsible for the breakdown (nanoporation) of cell plasma membranes after nanosecond pulse (nsEP) exposure remains poorly understood. Current theories focus exclusively on the electrical field, citing electrostriction, water dipole alignment and/or electrodeformation as the primary mechanisms for pore formation. However, the delivery of a high-voltage nsEP to cells by tungsten electrodes creates a multitude of biophysical phenomena, including electrohydraulic cavitation, electrochemical interactions, thermoelastic expansion, and others. To date, very limited research has investigated non-electric phenomena occurring during nsEP exposures and their potential effect on cell nanoporation. Of primary interest is the production of acoustic shock waves during nsEP exposure, as it is known that acoustic shock waves can cause membrane poration (sonoporation). Based on these observations, our group characterized the acoustic pressure transients generated by nsEP and determined if such transients played any role in nanoporation. In this paper, we show that nsEP exposures, equivalent to those used in cellular studies, are capable of generating high-frequency (2.5 MHz), high-intensity (>13 kPa) pressure transients. Using confocal microscopy to measure cell uptake of YO-PRO®-1 (indicator of nanoporation of the plasma membrane) and changing the electrode geometry, we determined that acoustic waves alone are not responsible for poration of the membrane.

  3. Sensitive and ultra-fast species detection using pulsed cavity ringdown spectroscopy

    KAUST Repository

    Alquaity, Awad; Es-sebbar, Et-touhami; Farooq, Aamir

    2015-01-01

    of ethylene in the mid-IR region near 949.47 cm-1. Each ringdown measurement is completed in less than 1 μs and the time period between successive pulses is 10 μs. The high sensitivity diagnostic has a noise-equivalent detection limit of 1.08 x 10-5 cm-1 which

  4. Harmonic pulsed excitation and motion detection of a vibrating reflective target.

    Science.gov (United States)

    Urban, Matthew W; Greenleaf, James F

    2008-01-01

    Elasticity imaging is an emerging medical imaging modality. Methods involving acoustic radiation force excitation and pulse-echo ultrasound motion detection have been investigated to assess the mechanical response of tissue. In this work new methods for dynamic radiation force excitation and motion detection are presented. The theory and model for harmonic motion detection of a vibrating reflective target are presented. The model incorporates processing of radio frequency data acquired using pulse-echo ultrasound to measure harmonic motion with amplitudes ranging from 100 to 10,000 nm. A numerical study was performed to assess the effects of different parameters on the accuracy and precision of displacement amplitude and phase estimation and showed how estimation errors could be minimized. Harmonic pulsed excitation is introduced as a multifrequency radiation force excitation method that utilizes ultrasound tonebursts repeated at a rate f(r). The radiation force, consisting of frequency components at multiples of f(r), is generated using 3.0 MHz ultrasound, and motion detection is performed simultaneously with 9.0 MHz pulse-echo ultrasound. A parameterized experimental analysis showed that displacement can be measured with small errors for motion with amplitudes as low as 100 nm. The parameterized numerical and experimental analyses provide insight into how to optimize acquisition parameters to minimize measurement errors.

  5. Numerical evaluation of pulse-echo damage detection in train rail

    CSIR Research Space (South Africa)

    Long, CS

    2014-01-01

    Full Text Available A guided wave based monitoring system for welded freight rail, has previously been developed. The existing system was designed to only detect complete breaks. Current research efforts are focused on including a pulse-echo mode of operation in order...

  6. Optimizing pulse-pileup detection for soft-x-ray spectroscopy

    International Nuclear Information System (INIS)

    Greenberger, A.J.

    1981-04-01

    The problem of optimizing detection of the pileup of randomly occurring exponential tail pulses in white noise is considered. An attempt is made to reduce the process to an algorithm that could practically be performed in real time. Quantitative estimates are made for the performance of such an optimum detector. The relation to a more general pattern recognition problem is mentioned

  7. Structure and dynamics of paramagnetic transients by pulsed EPR and NMR detection of nuclear resonance

    International Nuclear Information System (INIS)

    Trifunac, A.D.

    1981-01-01

    Structure and dynamics of transient radicals in pulse radiolysis can be studied by time resolved EPR and NMR techniques. EPR study of kinetics and relaxation is illustrated. The NMR detection of nuclear resonance in transient radicals is a new method which allows the study of hyperfine coupling, population dynamics, radical kinetics, and reaction mechanism. 9 figures

  8. Dynamics of ultra-short electromagnetic pulses in the system of chiral carbon nanotube waveguides in the presence of external alternating electric field

    Energy Technology Data Exchange (ETDEWEB)

    Konobeeva, N.N., E-mail: yana_nn@inbox.ru [Volgograd State University, University Avenue 100, Volgograd 400062 (Russian Federation); Belonenko, M.B. [Volgograd Institute of Business, Uzhno-ukrainskaya str., Volgograd 400048 (Russian Federation)

    2014-04-01

    The paper addresses the propagation of ultra-short optical pulses in chiral carbon nanotubes in the presence of external alternating electric field. Following the assumption that the considered optical pulses are represented in the form of discrete solitons, we analyze the wave equation for the electromagnetic field and consider the dynamics of pulses in external field, their initial amplitudes and frequencies.

  9. Detection of Irradiated Korean Wheat Flour by Viscosity and Pulsed Photostimulated Luminescence (PPSL) Methods

    International Nuclear Information System (INIS)

    Yi, S.D.; Chang, K.S.; Oh, M.J.

    2005-01-01

    This study was carried out to establish methods for irradiation detection of irradiation in Korean wheat flour by pulsed photostimulated luminescence (PPSL) and viscometric methods. The photon counts of the irradiated Korean wheat flour measured by PPSL immediately after irradiation increased with increasing irradiation dose. The photon counts in the irradiated Korean wheat flour almost disappeared with lapse of time after storage in normal room conditions, but irradiation detection was still possible after 6 months in darkroom conditions

  10. Ultrashort laser-pulse diagnostics for detection of ordering within an ion beam

    International Nuclear Information System (INIS)

    Calabrese, R.; Guidi, V.; Lenisa, P.; Mariotti, E.

    1996-01-01

    A novel diagnostic method to detect ordering within one-dimensional ion beams in a storage ring is presented. The ions are simultaneously excited by a ultrashort pulsed laser (≅1 ps) at two different locations along the beam and fluorescence is detected by a group of four photomultipliers. Correlation in fluorescence signals is a firm indication that the ion beam has an ordered structure. (orig.)

  11. Effect of pulsed electric field and pasteurisation treatments on the rheological properties of mango nectar (Mangifera indica

    Directory of Open Access Journals (Sweden)

    S. S. Manjunatha

    2015-01-01

    Full Text Available The rheological behaviour of pulsed electric field (PEF processed and thermally pasteurised mango nectar (Mangifera indica was evaluated using controlled stress rheometer. The mango nectar was subjected to pulsed electric field (PEF as well as thermal processing. The rheological parameter shear stress was measured up to the shear rate of 750 s-1 using co-axial cylinder attachment at wide range of temperatures from 10 to 70 °C. The investigation showed that pulsed electric field (PEF processed and thermally pasteurised mango nectar behaved like a pseudo plastic (shear thinning fluid and obeyed Herschel-Bulkley model (0.9780 0.893, p < 0.05 and flow activation energy (Ea was significantly (p < 0.05 affected by processing conditions. The results indicated that the pulsed electric field (PEF and thermal processing condition has affected the rheological properties of mango nectar. The combined equation relating to shear stress (τ with temperature and shear rate of mango nectar was established.

  12. Effects of pulsed electric fields pretreatment and drying method on drying characteristics and nutritive quality of blueberries

    Science.gov (United States)

    Fresh blueberries were pretreated with pulsed electric fields (PEF) at 2 kV/cm and then dried at 45, 60 and 75 degrees C by conventional hot air or vacuum drying. Drying characteristics and changes in contents of moisture, anthocyanin, total phenolics, vitamin C, and antioxidant activity in the blu...

  13. Selective extraction of intracellular components from the microalga Chlorella vulgaris by combined pulsed electric field-temperature treatment

    NARCIS (Netherlands)

    Postma, P.R.; Pataro, G.; Capitoli, M.; Barbosa, M.J.; Wijffels, R.H.; Eppink, M.H.M.; Olivieri, G.; Ferrari, G.

    2016-01-01

    The synergistic effect of temperature (25-65°C) and total specific energy input (0.55-1.11kWhkgDW -1) by pulsed electric field (PEF) on the release of intracellular components from the microalgae Chlorella vulgaris was studied. The combination of PEF with temperatures from

  14. Osmotic dehydration of blueberries pretreated with pulsed electric fields: Effects on drying rate, and microbiological and nutritional qualities

    Science.gov (United States)

    Fresh blueberries were treated by pulsed electric fields (PEF) at 2 kV/cm before osmotic dehydration in 70% sugar syrup. The changes in water loss, solids gain, populations of native microorganisms, antioxidant activity, contents of anthocyanins, predominant phenolic acids and flavonols, and total p...

  15. A bioluminescence ATP assay for estimating surface hydrophobicity and membrane damage of Escherichia coli cells treated with pulsed electric fields

    Science.gov (United States)

    Pulse Electric Field (PEF) treatments, a non-thermal process have been reported to injure and inactivate bacteria in liquid foods. However, the effect of this treatment on bacterial cell surface charge and hydrophobicity has not been investigated. Apple juice (AJ, pH 3.8) purchased from a wholesale ...

  16. Influence of vacuum impregnation and pulsed electric field on the freezing temperature and ice propagation rates of spinach leaves

    Science.gov (United States)

    Efforts are currently directed towards improving the quality of sensitive tissues of fruits and vegetables after freezing and thawing. One of the methods under investigation is the combination of vacuum impregnation (VI) with cryoprotectants and pulsed electric field (PEF) applied to the plant tiss...

  17. Pulsed electric field inactivation of E. coli O157:H7 and surrogate bacteria in orange juice

    Science.gov (United States)

    Introduction: United States FDA juice HACCP rules mandate that orange juice (OJ) processors treat juice for a 5 log reduction of the target pathogen. Thermal pasteurization, however, reduces the sensory characteristics of OJ by removing or altering volatile compounds. Pulsed electric field (PEF) ...

  18. Upscaling from benchtop processing to industrial scale production: More factors to be considered for pulsed electric field food processing

    Science.gov (United States)

    Pulsed electric field (PEF) processing has been intensively studied with benchtop scale experiments. However, there is still limited information regarding critical factors to be considered for PEF efficacy in microbial reduction with PEF processing at a pilot or commercial scale production of juice....

  19. Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production

    DEFF Research Database (Denmark)

    Nielsen, Henriette Boel; Sonne, Anne-Mette; Grunert, Klaus G.

    2009-01-01

    on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline...

  20. In vitro optical detection of simulated blood pulse in a human tooth pulp model.

    Science.gov (United States)

    Niklas, A; Hiller, K-A; Jaeger, A; Brandt, M; Putzger, J; Ermer, C; Schulz, I; Monkman, G; Giglberger, S; Hirmer, M; Danilov, S; Ganichev, S; Schmalz, G

    2014-01-01

    Noninvasive optical methods such as photoplethysmography, established for blood pulse detection in organs, have been proposed for vitality testing of human dental pulp. However, no information is available on the mechanism of action in a closed pulp chamber and on the impairing influence of other than pulpal blood flow sources. Therefore, the aim of the present in vitro study was to develop a device for the optical detection of pulpal blood pulse and to investigate the influence of different parameters (including gingival blood flow [GBF] simulation) on the derived signals. Air, Millipore water, human erythrocyte suspensions (HES), non-particulate hemoglobin suspension (NPHS), and lysed hemoglobin suspension (LHES) were pulsed through a flexible (silicone) or a rigid (glass) tube placed within an extracted human molar in a tooth-gingiva model. HES was additionally pulsed through a rigid tube around the tooth, simulating GBF alone or combined with the flow through the tooth by two separate peristaltic pumps. Light from high-power light-emitting diodes (625 nm (red) and 940 nm (infrared [IR]); Golden Dragon, Osram, Germany) was introduced to the coronal/buccal part of the tooth, and the signal amplitude [∆U, in volts] of transmitted light was detected by a sensor at the opposite side of the tooth. Signal processing was carried out by means of a newly developed blood pulse detector. Finally, experiments were repeated with the application of rubber dam (blue, purple, pink, and black), aluminum foil, and black antistatic plastic foil. Nonparametric statistical analysis was applied (n = 5; α = 0.05). Signals were obtained for HES and LHES, but not with air, Millipore water, or NPHS. Using a flexible tube, signals for HES were higher for IR compared to red light, whereas for the rigid tube, the signals were significantly higher for red light than for IR. In general, significantly less signal amplitude was recorded for HES with the rigid glass tube than with the

  1. Inactivation of Escherichia coli, Saccharomyces cerevisiae, and Lactobacillus brevis in Low-fat Milk by Pulsed Electric Field Treatment: A Pilot-scale Study

    OpenAIRE

    Lee, Gun Joon; Han, Bok Kung; Choi, Hyuk Joon; Kang, Shin Ho; Baick, Seung Chun; Lee, Dong-Un

    2015-01-01

    We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 ?s were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The ...

  2. Effect of Twisted Fiber Anisotropy in Cardiac Tissue on Ablation with Pulsed Electric Fields.

    Directory of Open Access Journals (Sweden)

    Fei Xie

    Full Text Available Ablation of cardiac tissue with pulsed electric fields is a promising alternative to current thermal ablation methods, and it critically depends on the electric field distribution in the heart.We developed a model that incorporates the twisted anisotropy of cardiac tissue and computed the electric field distribution in the tissue. We also performed experiments in rabbit ventricles to validate our model. We find that the model agrees well with the experimentally determined ablation volume if we assume that all tissue that is exposed to a field greater than 3 kV/cm is ablated. In our numerical analysis, we considered how tissue thickness, degree of anisotropy, and electrode configuration affect the geometry of the ablated volume. We considered two electrode configurations: two parallel needles inserted into the myocardium ("penetrating needles" configuration and one circular electrode each on epi- and endocardium, opposing each other ("epi-endo" configuration.For thick tissues (10 mm and moderate anisotropy ratio (a = 2, we find that the geometry of the ablated volume is almost unaffected by twisted anisotropy, i.e. it is approximately translationally symmetric from epi- to endocardium, for both electrode configurations. Higher anisotropy ratio (a = 10 leads to substantial variation in ablation width across the wall; these variations were more pronounced for the penetrating needle configuration than for the epi-endo configuration. For thinner tissues (4 mm, typical for human atria and higher anisotropy ratio (a = 10, the epi-endo configuration yielded approximately translationally symmetric ablation volumes, while the penetrating electrodes configuration was much more sensitive to fiber twist.These results suggest that the epi-endo configuration will be reliable for ablation of atrial fibrillation, independently of fiber orientation, while the penetrating electrode configuration may experience problems when the fiber orientation is not consistent

  3. Cationic peptide exposure enhances pulsed-electric-field-mediated membrane disruption.

    Science.gov (United States)

    Kennedy, Stephen M; Aiken, Erik J; Beres, Kaytlyn A; Hahn, Adam R; Kamin, Samantha J; Hagness, Susan C; Booske, John H; Murphy, William L

    2014-01-01

    The use of pulsed electric fields (PEFs) to irreversibly electroporate cells is a promising approach for destroying undesirable cells. This approach may gain enhanced applicability if the intensity of the PEF required to electrically disrupt cell membranes can be reduced via exposure to a molecular deliverable. This will be particularly impactful if that reduced PEF minimally influences cells that are not exposed to the deliverable. We hypothesized that the introduction of charged molecules to the cell surfaces would create regions of enhanced transmembrane electric potential in the vicinity of each charged molecule, thereby lowering the PEF intensity required to disrupt the plasma membranes. This study will therefore examine if exposure to cationic peptides can enhance a PEF's ability to disrupt plasma membranes. We exposed leukemia cells to 40 μs PEFs in media containing varying concentrations of a cationic peptide, polyarginine. We observed the internalization of a membrane integrity indicator, propidium iodide (PI), in real time. Based on an individual cell's PI fluorescence versus time signature, we were able to determine the relative degree of membrane disruption. When using 1-2 kV/cm, exposure to >50 μg/ml of polyarginine resulted in immediate and high levels of PI uptake, indicating severe membrane disruption, whereas in the absence of peptide, cells predominantly exhibited signatures indicative of no membrane disruption. Additionally, PI entered cells through the anode-facing membrane when exposed to cationic peptide, which was theoretically expected. Exposure to cationic peptides reduced the PEF intensity required to induce rapid and irreversible membrane disruption. Critically, peptide exposure reduced the PEF intensities required to elicit irreversible membrane disruption at normally sub-electroporation intensities. We believe that these cationic peptides, when coupled with current advancements in cell targeting techniques will be useful tools in

  4. Effect of Twisted Fiber Anisotropy in Cardiac Tissue on Ablation with Pulsed Electric Fields.

    Science.gov (United States)

    Xie, Fei; Zemlin, Christian W

    2016-01-01

    Ablation of cardiac tissue with pulsed electric fields is a promising alternative to current thermal ablation methods, and it critically depends on the electric field distribution in the heart. We developed a model that incorporates the twisted anisotropy of cardiac tissue and computed the electric field distribution in the tissue. We also performed experiments in rabbit ventricles to validate our model. We find that the model agrees well with the experimentally determined ablation volume if we assume that all tissue that is exposed to a field greater than 3 kV/cm is ablated. In our numerical analysis, we considered how tissue thickness, degree of anisotropy, and electrode configuration affect the geometry of the ablated volume. We considered two electrode configurations: two parallel needles inserted into the myocardium ("penetrating needles" configuration) and one circular electrode each on epi- and endocardium, opposing each other ("epi-endo" configuration). For thick tissues (10 mm) and moderate anisotropy ratio (a = 2), we find that the geometry of the ablated volume is almost unaffected by twisted anisotropy, i.e. it is approximately translationally symmetric from epi- to endocardium, for both electrode configurations. Higher anisotropy ratio (a = 10) leads to substantial variation in ablation width across the wall; these variations were more pronounced for the penetrating needle configuration than for the epi-endo configuration. For thinner tissues (4 mm, typical for human atria) and higher anisotropy ratio (a = 10), the epi-endo configuration yielded approximately translationally symmetric ablation volumes, while the penetrating electrodes configuration was much more sensitive to fiber twist. These results suggest that the epi-endo configuration will be reliable for ablation of atrial fibrillation, independently of fiber orientation, while the penetrating electrode configuration may experience problems when the fiber orientation is not consistent across the

  5. Metal release in a stainless steel pulsed electric field (PEF) system Part II. The treatment of orange juice; related to legislation and treatment chamber lifetime

    NARCIS (Netherlands)

    Roodenburg, B.; Morren, J.; Berg, H.E.; Haan, S.W.H.de

    2005-01-01

    In the last decennia, there is an increasing interest in pulsed electric field (PEF) treatment. The product is often treated in a continuous flow treatment chamber with stainless steel electrodes and exposed to short pulsed electric fields, typically 2-4 kV mm-1 during 1-10 μs. Due to direct contact

  6. Predicting dynamic range and intensity discrimination for electrical pulse-train stimuli using a stochastic auditory nerve model: the effects of stimulus noise.

    Science.gov (United States)

    Xu, Yifang; Collins, Leslie M

    2005-06-01

    This work investigates dynamic range and intensity discrimination for electrical pulse-train stimuli that are modulated by noise using a stochastic auditory nerve model. Based on a hypothesized monotonic relationship between loudness and the number of spikes elicited by a stimulus, theoretical prediction of the uncomfortable level has previously been determined by comparing spike counts to a fixed threshold, Nucl. However, no specific rule for determining Nucl has been suggested. Our work determines the uncomfortable level based on the excitation pattern of the neural response in a normal ear. The number of fibers corresponding to the portion of the basilar membrane driven by a stimulus at an uncomfortable level in a normal ear is related to Nucl at an uncomfortable level of the electrical stimulus. Intensity discrimination limens are predicted using signal detection theory via the probability mass function of the neural response and via experimental simulations. The results show that the uncomfortable level for pulse-train stimuli increases slightly as noise level increases. Combining this with our previous threshold predictions, we hypothesize that the dynamic range for noise-modulated pulse-train stimuli should increase with additive noise. However, since our predictions indicate that intensity discrimination under noise degrades, overall intensity coding performance may not improve significantly.

  7. Surface Crack Detection for Carbon Fiber Reinforced Plastic Materials Using Pulsed Eddy Current Based on Rectangular Differential Probe

    Directory of Open Access Journals (Sweden)

    Jialong Wu

    2014-01-01

    Full Text Available Aiming at the surface defect inspection of carbon fiber reinforced composite, the differential and the direct measurement finite element simulation models of pulsed eddy current flaw detection were built. The principle of differential pulsed eddy current detection was analyzed and the sensitivity of defect detection was compared through two kinds of measurements. The validity of simulation results was demonstrated by experiments. The simulation and experimental results show that the pulsed eddy current detection method based on rectangular differential probe can effectively improve the sensitivity of surface defect detection of carbon fiber reinforced composite material.

  8. The pulse duration of electrical stimulation influences H-reflexes but not corticospinal excitability for tibialis anterior.

    Science.gov (United States)

    Hindle, Alyssa R; Lou, Jenny W H; Collins, David F

    2014-10-01

    The afferent volley generated by neuromuscular electrical stimulation (NMES) influences corticospinal (CS) excitability and frequent NMES sessions can strengthen CS pathways, resulting in long-term improvements in function. This afferent volley can be altered by manipulating NMES parameters. Presently, we manipulated one such parameter, pulse duration, during NMES over the common peroneal nerve and assessed the influence on H-reflexes and CS excitability. We hypothesized that compared with shorter pulse durations, longer pulses would (i) shift the H-reflex recruitment curve to the left, relative to the M-wave curve; and (ii) increase CS excitability more. Using 3 pulse durations (50, 200, 1000 μs), M-wave and H-reflex recruitment curves were collected and, in separate experiments, CS excitability was assessed by comparing motor evoked potentials elicited before and after 30 min of NMES. Despite finding a leftward shift in the H-reflex recruitment curve when using the 1000 μs pulse duration, consistent with a larger afferent volley for a given efferent volley, the increases in CS excitability were not influenced by pulse duration. Hence, although manipulating pulse duration can alter the relative recruitment of afferents and efferents in the common peroneal nerve, under the present experimental conditions it is ineffective for maximizing CS excitability for rehabilitation.

  9. Continuous raw skim milk processing by pulsed electric field at non-lethal temperature: effect on microbial inactivation and functional properties

    OpenAIRE

    Floury , Juliane; Grosset , Noël; Leconte , Nadine; Pasco , Maryvonne; Madec , Marie-Noëlle; Jeantet , Romain

    2006-01-01

    International audience; Pulsed electric field (PEF) is an emerging non-thermal processing technology used to inactivate microorganisms in liquid foods such as milk. The objective of this research was to study the effectiveness of continuous PEF equipment (square wave pulses) on total microorganisms of raw skim milk and on Salmonella enteritidis inactivation under moderate temperatures (T < 50 °C). Processing parameters (electric field and pulse width) were chosen as follows: 45 kV*cm-1/500 ns...

  10. Temporal correlation measurements of pulsed dual CO2 lidar returns. [for atmospheric pollution detection

    Science.gov (United States)

    Menyuk, N.; Killinger, D. K.

    1981-01-01

    A pulsed dual-laser direct-detection differential-absorption lidar DIAL system, operating near 10.6 microns, is used to measure the temporal correlation and statistical properties of backscattered returns from specular and diffuse topographic targets. Results show that atmospheric-turbulence fluctuations can effectively be frozen for pulse separation times on the order of 1-3 msec or less. The diffuse target returns, however, yielded a much lower correlation than that obtained with the specular targets; this being due to uncorrelated system noise effects and different statistics for the two types of target returns.

  11. Occurrence of sublethal injury after pulsed electric fields depending on the micro-organism, the treatment medium ph and the intensity of the treatment investigated.

    Science.gov (United States)

    García, D; Gómez, N; Mañas, P; Condón, S; Raso, J; Pagán, R

    2005-01-01

    The objective was to investigate the occurrence of sublethal injury after pulsed electric field (PEF) depending on the treatment time, the electric field strength and the pH of the treatment media in two Gram-positive (Bacillus subtilis ssp. niger, Listeria monocytogenes) and six Gram-negative (Escherichia coli, Escherichia coli O157:H7, Pseudomonas aeruginosa, Salmonella serotype Senftenberg 775W, Salmonella serotype Typhimurium, Yersinia enterocolitica) bacterial strains. A characteristic behaviour was observed for the Gram-positive and Gram-negative bacteria studied. Whereas Gram-positive bacteria showed a higher PEF resistance at pH 7.0, the Gram-negative were more resistant at pH 4.0. In these conditions, in which bacteria showed their maximum resistance, a large proportion of sublethally injured cells were detected. In most cases, the longer the treatment time and the higher the electric field applied, the greater the proportion of sublethally injured cells that were detected. No sublethal injury was detected when Gram-positive bacteria were treated at pH 4.0 and Gram-negative at pH 7.0. Sublethal injury was detected after PEF so, bacterial inactivation by PEF is not an 'all or nothing' event. This work could be useful for improving food preservation by PEF.

  12. High intensity pulsed electric field as an innovative technique for extraction of bioactive compounds-A review.

    Science.gov (United States)

    Yan, Liang-Gong; He, Lang; Xi, Jun

    2017-09-02

    How to extract bioactive compounds safely and efficiently is one of the problems for the food and pharmaceutical industry. In recent years, several novel extraction techniques have been proposed. To pursue a more efficient method for industrial production, high intensity pulsed electric field (HIPEF) extraction technique has been developed. HIPEF extraction technique, which is based on the conventional pulsed electric field (PEF), provided higher electric field intensity and a special continuous extraction system, and it has confirmed less extraction time, higher extraction yield, and mild processing temperature. So this innovative technique is promising for application of industrial production. This review was devoted to introducing the recent achievement of HIPEF extraction technique, including novel HIPEF continuous extraction system, principles and mechanisms; the critical process factors influencing its performance applications; and comparison of HIPEF extraction with other extraction techniques. In the end, the defects and future trends of HIPEF extraction were also discussed.

  13. Separation of large DNA molecules by applying pulsed electric field to size exclusion chromatography-based microchip

    Science.gov (United States)

    Azuma, Naoki; Itoh, Shintaro; Fukuzawa, Kenji; Zhang, Hedong

    2018-02-01

    Through electrophoresis driven by a pulsed electric field, we succeeded in separating large DNA molecules with an electrophoretic microchip based on size exclusion chromatography (SEC), which was proposed in our previous study. The conditions of the pulsed electric field required to achieve the separation were determined by numerical analyses using our originally proposed separation model. From the numerical results, we succeeded in separating large DNA molecules (λ DNA and T4 DNA) within 1600 s, which was approximately half of that achieved under a direct electric field in our previous study. Our SEC-based electrophoresis microchip will be one of the effective tools to meet the growing demand of faster and more convenient separation of large DNA molecules, especially in the field of epidemiological research of infectious diseases.

  14. Electrical detection of liquid lithium leaks from pipe joints

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, J. A., E-mail: jschwart@pppl.gov; Jaworski, M. A.; Mehl, J.; Kaita, R.; Mozulay, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)

    2014-11-15

    A test stand for flowing liquid lithium is under construction at Princeton Plasma Physics Laboratory. As liquid lithium reacts with atmospheric gases and water, an electrical interlock system for detecting leaks and safely shutting down the apparatus has been constructed. A defense in depth strategy is taken to minimize the risk and impact of potential leaks. Each demountable joint is diagnosed with a cylindrical copper shell electrically isolated from the loop. By monitoring the electrical resistance between the pipe and the copper shell, a leak of (conductive) liquid lithium can be detected. Any resistance of less than 2 kΩ trips a relay, shutting off power to the heaters and pump. The system has been successfully tested with liquid gallium as a surrogate liquid metal. The circuit features an extensible number of channels to allow for future expansion of the loop. To ease diagnosis of faults, the status of each channel is shown with an analog front panel LED, and monitored and logged digitally by LabVIEW.

  15. Determination of carbohydrates using pulsed amperometric detection combined with anion exchange separations

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, W.T.; Pohl, C.A.; Rubin, R.

    1987-06-01

    Carbohydrates, including the monosaccharides commonly found in wood and wood pulp hydrolyzates, are separated by anion exchange chromatography using hydroxide and acetate eluants and are determined using pulsed amperometric detection. The detection method is based on oxidizing the sugars in a flow-through electrochemical cell equipped with a gold working electrode. A repeating cycle of three potentials is used: the first to oxidize the carbohydrates and measure the current generated, and two subsequent pulses to clean the electrode surface of oxidation products. The method is fast, sensitive, and requires no pre-column derivatization. It is applied to a sample of hydrolyzed wood pulp, which can be analyzed after minimal sample preparation. Detection limits are of the order of 1 mg/kg for monosaccharides in a 50 micro L injection. (Refs. 8).

  16. [A quick algorithm of dynamic spectrum photoelectric pulse wave detection based on LabVIEW].

    Science.gov (United States)

    Lin, Ling; Li, Na; Li, Gang

    2010-02-01

    Dynamic spectrum (DS) detection is attractive among the numerous noninvasive blood component detection methods because of the elimination of the main interference of the individual discrepancy and measure conditions. DS is a kind of spectrum extracted from the photoelectric pulse wave and closely relative to the artery blood. It can be used in a noninvasive blood component concentration examination. The key issues in DS detection are high detection precision and high operation speed. The precision of measure can be advanced by making use of over-sampling and lock-in amplifying on the pick-up of photoelectric pulse wave in DS detection. In the present paper, the theory expression formula of the over-sampling and lock-in amplifying method was deduced firstly. Then in order to overcome the problems of great data and excessive operation brought on by this technology, a quick algorithm based on LabVIEW and a method of using external C code applied in the pick-up of photoelectric pulse wave were presented. Experimental verification was conducted in the environment of LabVIEW. The results show that by the method pres ented, the speed of operation was promoted rapidly and the data memory was reduced largely.

  17. Advanced electrical current measurements of microdischarges: evidence of sub-critical pulses and ion currents in barrier discharge in air

    Science.gov (United States)

    Synek, Petr; Zemánek, Miroslav; Kudrle, Vít; Hoder, Tomáš

    2018-04-01

    Electrical current measurements in corona or barrier microdischarges are a challenge as they require both high temporal resolution and a large dynamic range of the current probe used. In this article, we apply a simple self-assembled current probe and compare it to commercial ones. An analysis in the time and frequency domain is carried out. Moreover, an improved methodology is presented, enabling both temporal resolution in sub-nanosecond times and current sensitivity in the order of tens of micro-amperes. Combining this methodology with a high-tech oscilloscope and self-developed software, a unique statistical analysis of currents in volume barrier discharge driven in atmospheric-pressure air is made for over 80 consecutive periods of a 15 kHz applied voltage. We reveal the presence of repetitive sub-critical current pulses and conclude that these can be identified with the discharging of surface charge microdomains. Moreover, extremely low, long-lasting microsecond currents were detected which are caused by ion flow, and are analysed in detail. The statistical behaviour presented gives deeper insight into the discharge physics of these usually undetectable current signals.

  18. Physical and structural changes in liquid whole egg treated with high-intensity pulsed electric fields.

    Science.gov (United States)

    Marco-Molés, Raquel; Rojas-Graü, María A; Hernando, Isabel; Pérez-Munuera, Isabel; Soliva-Fortuny, Robert; Martín-Belloso, Olga

    2011-03-01

    Liquid whole egg (LWE) is currently pasteurized through the application of heat; however, this treatment entails deleterious effects against some of the functional and technological properties of the product. In this study, the effect of high-intensity pulsed electric fields (HIPEF) processing (field strength: 19, 32, and 37 kV/cm) was compared to the traditional heat pasteurization (66 °C for 4.5 min). Different physical and structural characteristics of LWE, subjected or not to homogenization, were evaluated and compared, having the untreated LWE as a reference. Thermal treatment caused an increase in the viscosity of LWE, especially in nonhomogenized samples. HIPEF treatments did not modify the original color of LWE, whereas thermally treated samples developed an opaque appearance. LWE treated at 19 and 32 kV/cm exhibited a similar foaming capacity as fresh untreated egg, whereas thermal processing and PEF treatments of 37 kV/cm caused a substantial decrease in the foaming capacity of untreated liquid egg. Regarding the microstructure, the lipoprotein matrix appeared to be less affected by the HIPEF than by heat treatment if compared to the control. In addition, heat pasteurization had a significant impact on both the water-soluble protein content of the LWE samples (19.5% to 23.6% decrease) and the mechanical properties of the egg gels (up to 21.3% and 14.5% increase in hardness and cohesiveness, respectively). On the other hand, these parameters were not substantially affected in the HIPEF-treated samples. Heat-induced gels obtained from HIPEF-treated samples did not exhibit remarkable differences in the water-holding capacity (WHC) with respect to heat-pasteurized samples. The impact of high-intensity pulsed electric fields (HIPEF) processing on technological properties of liquid-whole egg was investigated and compared to that of thermal processing. Heat treatments cause a severe impact on the foaming capacity, the water-soluble protein content, and the

  19. A low-power, CMOS peak detect and hold circuit for nuclear pulse spectroscopy

    International Nuclear Information System (INIS)

    Ericson, M.N.; Simpson, M.L.; Britton, C.L.; Allen, M.D.; Kroeger, R.A.; Inderhees, S.E.

    1994-01-01

    A low-power CMOS peak detecting track and hold circuit optimized for nuclear pulse spectroscopy is presented. The circuit topology eliminates the need for a rectifying diode, reducing the effect of charge injection into the hold capacitor, incorporates a linear gate at the input to prevent pulse pileup, and uses dynamic bias control that minimizes both pedestal and droop. Both positive-going and negative-going pulses are accommodated using a complementary set of track and hold circuits. Full characterization of the design fabricated in 1.2μm CMOS including dynamic range, integral nonlinearity, droop rate, pedestal, and power measurements is presented. Additionally, analysis and design approaches for optimization of operational characteristics are discussed

  20. Pulse pile-up in nuclear particle detection systems with rapidly varying counting rates

    International Nuclear Information System (INIS)

    Datlowe, D.W.

    1977-01-01

    Pulse pile-up in nuclear particle detection systems is the distortion of the measured pulse height distribution which occurs when there is a significant probability that more than one particle will arrive within the detector resolving time. This paper treats the problem in cases where the probability of pile-up varies on a time scale comparable to the rise time of the detector system electronics. These variations introduce structure into the pulse height distributions which cannot occur for a time-independent pile-up probability. Three classes of problems which exemplify these effects are as follows: 1) Pile-up rejection circuits. 2) Cascaded nuclear decays, in which the lifetime for emission of a second X-ray is comparable to the detector rise time. 3) Bursts of particles where the intensity is modulated on a time scale comparable to the detector rise time. These problems are solved computationally by an extension of a numerical technique previously developed. (Auth.)

  1. DynPeak: An Algorithm for Pulse Detection and Frequency Analysis in Hormonal Time Series

    Science.gov (United States)

    Vidal, Alexandre; Zhang, Qinghua; Médigue, Claire; Fabre, Stéphane; Clément, Frédérique

    2012-01-01

    The endocrine control of the reproductive function is often studied from the analysis of luteinizing hormone (LH) pulsatile secretion by the pituitary gland. Whereas measurements in the cavernous sinus cumulate anatomical and technical difficulties, LH levels can be easily assessed from jugular blood. However, plasma levels result from a convolution process due to clearance effects when LH enters the general circulation. Simultaneous measurements comparing LH levels in the cavernous sinus and jugular blood have revealed clear differences in the pulse shape, the amplitude and the baseline. Besides, experimental sampling occurs at a relatively low frequency (typically every 10 min) with respect to LH highest frequency release (one pulse per hour) and the resulting LH measurements are noised by both experimental and assay errors. As a result, the pattern of plasma LH may be not so clearly pulsatile. Yet, reliable information on the InterPulse Intervals (IPI) is a prerequisite to study precisely the steroid feedback exerted on the pituitary level. Hence, there is a real need for robust IPI detection algorithms. In this article, we present an algorithm for the monitoring of LH pulse frequency, basing ourselves both on the available endocrinological knowledge on LH pulse (shape and duration with respect to the frequency regime) and synthetic LH data generated by a simple model. We make use of synthetic data to make clear some basic notions underlying our algorithmic choices. We focus on explaining how the process of sampling affects drastically the original pattern of secretion, and especially the amplitude of the detectable pulses. We then describe the algorithm in details and perform it on different sets of both synthetic and experimental LH time series. We further comment on how to diagnose possible outliers from the series of IPIs which is the main output of the algorithm. PMID:22802933

  2. Accuracy of carboxyhemoglobin detection by pulse CO-oximetry during hypoxemia.

    Science.gov (United States)

    Feiner, John R; Rollins, Mark D; Sall, Jeffrey W; Eilers, Helge; Au, Paul; Bickler, Philip E

    2013-10-01

    Carbon monoxide poisoning is a significant problem in most countries, and a reliable method of quick diagnosis would greatly improve patient care. Until the recent introduction of a multiwavelength "pulse CO-oximeter" (Masimo Rainbow SET(®) Radical-7), obtaining carboxyhemoglobin (COHb) levels in blood required blood sampling and laboratory analysis. In this study, we sought to determine whether hypoxemia, which can accompany carbon monoxide poisoning, interferes with the accurate detection of COHb. Twelve healthy, nonsmoking, adult volunteers were fitted with 2 standard pulse-oximeter finger probes and 2 Rainbow probes for COHb detection. A radial arterial catheter was placed for blood sampling during 3 interventions: (1) increasing hypoxemia in incremental steps with arterial oxygen saturations (SaO2) of 100% to 80%; (2) normoxia with incremental increases in %COHb to 12%; and (3) elevated COHb combined with hypoxemia with SaO2 of 100% to 80%. Pulse-oximeter (SpCO) readings were compared with simultaneous arterial blood values at the various increments of hypoxemia and carboxyhemoglobinemia (≈25 samples per subject). Pulse CO-oximeter performance was analyzed by calculating the mean bias (SpCO - %COHb), standard deviation of the bias (precision), and the root-mean-square error (A(rms)). The Radical-7 accurately detected hypoxemia with both normal and elevated levels of COHb (bias mean ± SD: 0.44% ± 1.69% at %COHb <4%, and -0.29% ± 1.64% at %COHb ≥4%, P < 0.0001, and A(rms) 1.74% vs 1.67%). COHb was accurately detected during normoxia and moderate hypoxia (bias mean ± SD: -0.98 ± 2.6 at SaO2 ≥95%, and -0.7 ± 4.0 at SaO2 <95%, P = 0.60, and A(rms) 2.8% vs 4.0%), but when SaO2 decreased below approximately 85%, the pulse CO-oximeter always gave low signal quality errors and did not report SpCO values. In healthy volunteers, the Radical-7 pulse CO-oximeter accurately detects hypoxemia with both low and elevated COHb levels, and accurately detects COHb

  3. 46 CFR 108.407 - Detectors for electric fire detection system.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Detectors for electric fire detection system. 108.407... DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems § 108.407 Detectors for electric fire detection system. (a) Each detector in an electric fire detection system must be located where— (1) No...

  4. Online fouling detection in electrical circulation heaters using neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Lalot, S. [M.E.T.I.E.R., Longuenesse Cedex (France); Universite de Valenciennes (France). LME; Lecoeuche, S. [M.E.T.I.E.R., Longuenesse Cedex (France); Universite de Lille (France). Laboratoire 13D

    2003-06-01

    Here is presented a method that is able to detect fouling during the service of a circulation electrical heater. The neural based technique is divided in two major steps: identification and classification. Each step uses a neural network, the connection weights of the first one being the inputs of the second network. Each step is detailed and the main characteristics and abilities of the two neural networks are given. It is shown that the method is able to discriminate fouling from viscosity modification that would lead to the same type of effect on the total heat transfer coefficient. (author)

  5. The Accuracy of Pulse Spectroscopy for Detecting Hypoxemia and Coexisting Methemoglobin or Carboxyhemoglobin.

    Science.gov (United States)

    Kulcke, Axel; Feiner, John; Menn, Ingolf; Holmer, Amadeus; Hayoz, Josef; Bickler, Philip

    2016-06-01

    Pulse spectroscopy is a new noninvasive technology involving hundreds of wavelengths of visible and infrared light, enabling the simultaneous quantitation of multiple types of normal and dysfunctional hemoglobin. We evaluated the accuracy of a first-generation pulse spectroscopy system (V-Spec™ Monitoring System, Senspec, Germany) in measuring oxygen saturation (SpO2) and detecting carboxyhemoglobin (COHb) or methemoglobin (MetHb), alone or simultaneously, with hypoxemia. Nineteen volunteers were fitted with V-Spec probes on the forehead and fingers. A radial arterial catheter was placed for blood sampling during (1) hypoxemia with arterial oxygen saturations (SaO2) of 100% to 58.5%; (2) normoxia with MetHb and COHb increased to approximately 10%; (3) 10% COHb or MetHb combined with hypoxemia with SaO2 of 100% to 80%. Standard measures of pulse-oximetry performance were calculated: bias (pulse spectroscopy measured value - arterial measured value) mean ± SD and root-mean-square error (Arms). The SpO2 bias for SaO2 approximately 60% to 100% was 0.06% ± 1.30% and Arms of 1.30%. COHb bias was 0.45 ± 1.63, with an Arms of 1.69% overall, and did not degrade substantially during moderate hypoxemia. MetHb bias was 0.36 ± 0.80 overall and stayed small with hypoxemia. Arms was 0.88 and was 10%. Pulse spectroscopy accurately detects hypoxemia, MetHb, and COHb. The technology also accurately detects these dysfunctional hemoglobins during hypoxemia. Future releases of this device may have an improved SpO2 algorithm that is more robust with methemoglobinemia.

  6. Electrical and optical analysis of fast transient discharges in a pulsed corona pilot unit

    NARCIS (Netherlands)

    Blom, P.P.M.; Smulders, H.W.M.; Heesch, van E.J.M.; Laan, van der P.C.T.

    1997-01-01

    We give a detailed analysis of intense pulsed corona dis charges. CCD movies and current, voltage and energy in put measurements are the basis of the description. The discharges are generated in a 1.5 kW pilot unit, which cre ates pulsed corona discharges energized by 100 kV pulses of 200 us width,

  7. Characteristics and Antitumor Activity of Morchella esculenta Polysaccharide Extracted by Pulsed Electric Field

    Directory of Open Access Journals (Sweden)

    Chao Liu

    2016-06-01

    Full Text Available Polysaccharides from Morchella esculenta have been proven to be functional and helpful for humans. The purpose of this study was to investigate the chemical structure and anti-proliferating and antitumor activities of a Morchella esculenta polysaccharide (MEP extracted by pulsed electric field (PEF in submerged fermentation. The endo-polysaccharide was separated and purified by column chromatography and Gel permeation chromatography, and analyzed by gas chromatography. The MEP with an average molecular weight of 81,835 Da consisted of xylose, glucose, mannose, rhamnose and galactose at the ratio of 5.4:5.0:6.5:7.8:72.3. Structure of MEP was further analyzed by Fourier-transform infrared spectroscopy and 1H and 13C liquid-state nuclear magnetic resonance spectroscopy. Apoptosis tests proved that MEP could inhibit the proliferation and growth of human colon cancer HT-29 cells in a time- and dose-dependent manner within 48 h. This study provides more information on chemical structure of anti-proliferating polysaccharides isolated from Morchella esculenta.

  8. Effects of pulsed electric fields on pathogenic microorganisms of major concern in fluid foods: a review.

    Science.gov (United States)

    Mosqueda-Melgar, Jonathan; Elez-Martínez, Pedro; Raybaudi-Massilia, Rosa M; Martín-Belloso, Olga

    2008-09-01

    Pathogenic microorganisms such as Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Yersinia enterocolitica, and Campylobacter jejuni have been implicated in foodborne diseases and outbreaks worldwide. These bacteria have been associated with the consumption of fresh fruit juices, milk, and dairy products, which are foodstuff, highly demanded by consumers in retails and supermarkets. Nowadays, consumers require high quality, fresh-like, and safe foods. Pulsed electric field (PEF) is a non-thermal preservation method, able to inactivate pathogenic microorganisms without significant loss of the organoleptic and nutritional properties of food. The PEF treatment effectiveness to destroy bacteria such as Listeria innocua, E. coli, Salmonella Typhimurium, E. coli O157:H7 and E. coli 8739 at pasteurization levels (> or = 5.0 log(10) cycles) in some fluid foods was reported. However, data on the inactivation of some microorganisms such as Bacillus cereus, Staphylococcus aureus, Yersinia enterocolitica, and Campylobacter jejuni in fluid foods by PEF processing is very limited. Therefore, future works should be focused toward the inactivation of these pathogenic bacteria in real foods.

  9. Spectral representation of the particle production out of equilibrium—Schwinger mechanism in pulsed electric fields

    International Nuclear Information System (INIS)

    Fukushima, Kenji

    2014-01-01

    We develop a formalism to describe the particle production out of equilibrium in terms of dynamical spectral functions, i.e. Wigner transformed Pauli–Jordan's and Hadamard's functions. We take an explicit example of a spatially homogeneous scalar theory under pulsed electric fields and investigate the time evolution of the spectral functions. In the out-state we find an oscillatory peak in Hadamard's function as a result of the mixing between positive- and negative-energy waves. The strength of this peak is of the linear order of the Bogoliubov mixing coefficient, whereas the peak corresponding to the Schwinger mechanism is of the quadratic order. Between the in- and the out-states we observe a continuous flow of the spectral peaks together with two transient oscillatory peaks. We also discuss the medium effect at finite temperature and density. We emphasize that the entire structure of the spectral functions conveys rich information on real-time dynamics including the particle production. (paper)

  10. Effects of nuclear electromagnetic pulse (EMP) on synchronous stability of the electric power system

    International Nuclear Information System (INIS)

    Manweiler, R.W.

    1975-11-01

    The effects of a nuclear electromagnetic pulse (EMP) on the synchronous stability of the electric power transmission and distribution systems are evaluated. The various modes of coupling of EMP to the power system are briefly discussed, with particular emphasis on those perturbations affecting the synchronous stability of the transmission system. A brief review of the fundamental concepts of the stability problem is given, with a discussion of the general characteristics of transient analysis. A model is developed to represent single sets as well as repetitive sets of multiple faults on the distribution systems, as might be produced by EMP. The results of many numerical stability calculations are presented to illustrate the transmission system's response from different types of perturbations. The important parameters of both multiple and repetitive faults are studied, including the dependence of the response on the size of the perturbed area, the fault density, and the effective impedance between the fault location and the transmission system. Both major load reduction and the effect of the opening of tie lines at the time of perturbation are also studied. We conclude that there is a high probability that EMP can induce perturbations on the distribution networks causing a large portion of the transmission network in the perturbed area to lose synchronism. The result would be an immediate and massive power failure

  11. Effect of various gases and chemical catalysts on phenol degradation pathways by pulsed electrical discharges

    Energy Technology Data Exchange (ETDEWEB)

    Shen Yongjun [Institute of Environmental Pollution Control Technologies, Zhejiang University, Hangzhou 310028 (China); Lei Lecheng [Institute of Environmental Pollution Control Technologies, Zhejiang University, Hangzhou 310028 (China)], E-mail: lclei@zju.edu.cn; Zhang Xingwang; Zhou Minghua; Zhang Yi [Institute of Environmental Pollution Control Technologies, Zhejiang University, Hangzhou 310028 (China)

    2008-02-11

    The processes of phenol degradation by pulsed electrical discharges were investigated under several kinds of discharge atmospheres (oxygen, argon, nitrogen and ozone) and chemical catalysts (ferrous ion and hydrogen peroxide). The temporal variations of the concentrations of phenol and the intermediate products were monitored by HPLC and GC-MS, respectively. It has been found that the effect of various gases bubbling on phenol degradation rate ranked in the following order: oxygen-containing ozone > oxygen > argon > nitrogen. The high gas bubbling flow rate was beneficial to the removal of phenol. It was found that the degradation proceeded differently when in the presence and absence of catalysts. The phenol removal rate was increased when ferrous ion was added. This considerable enhancement may be due to the Fenton's reaction. What's more, putting the chemical additives hydrogen peroxide into the reactor led to a dramatic increase in phenol degradation rate. The mechanism was due to the direct or indirect photolysis and pyrolysis destruction in plasma channel. Furthermore, the intermediate products were monitored by GC-MS under three degradation conditions. More THBs were generated under degradation conditions without gases bubbling or adding any catalyst, and more DHBs under the condition of adding ferrous ion, and more carboxylic acids under the condition of oxygen-containing ozone gas bubbling. Consequently, three distinct degradation pathways based on different conditions were proposed.

  12. Effect of various gases and chemical catalysts on phenol degradation pathways by pulsed electrical discharges.

    Science.gov (United States)

    Shen, Yongjun; Lei, Lecheng; Zhang, Xingwang; Zhou, Minghua; Zhang, Yi

    2008-02-11

    The processes of phenol degradation by pulsed electrical discharges were investigated under several kinds of discharge atmospheres (oxygen, argon, nitrogen and ozone) and chemical catalysts (ferrous ion and hydrogen peroxide). The temporal variations of the concentrations of phenol and the intermediate products were monitored by HPLC and GC-MS, respectively. It has been found that the effect of various gases bubbling on phenol degradation rate ranked in the following order: oxygen-containing ozone>oxygen>argon>nitrogen. The high gas bubbling flow rate was beneficial to the removal of phenol. It was found that the degradation proceeded differently when in the presence and absence of catalysts. The phenol removal rate was increased when ferrous ion was added. This considerable enhancement may be due to the Fenton's reaction. What's more, putting the chemical additives hydrogen peroxide into the reactor led to a dramatic increase in phenol degradation rate. The mechanism was due to the direct or indirect photolysis and pyrolysis destruction in plasma channel. Furthermore, the intermediate products were monitored by GC-MS under three degradation conditions. More THBs were generated under degradation conditions without gases bubbling or adding any catalyst, and more DHBs under the condition of adding ferrous ion, and more carboxylic acids under the condition of oxygen-containing ozone gas bubbling. Consequently, three distinct degradation pathways based on different conditions were proposed.

  13. Field-effect transistors as electrically controllable nonlinear rectifiers for the characterization of terahertz pulses

    Science.gov (United States)

    Lisauskas, Alvydas; Ikamas, Kestutis; Massabeau, Sylvain; Bauer, Maris; ČibiraitÄ--, DovilÄ--; Matukas, Jonas; Mangeney, Juliette; Mittendorff, Martin; Winnerl, Stephan; Krozer, Viktor; Roskos, Hartmut G.

    2018-05-01

    We propose to exploit rectification in field-effect transistors as an electrically controllable higher-order nonlinear phenomenon for the convenient monitoring of the temporal characteristics of THz pulses, for example, by autocorrelation measurements. This option arises because of the existence of a gate-bias-controlled super-linear response at sub-threshold operation conditions when the devices are subjected to THz radiation. We present measurements for different antenna-coupled transistor-based THz detectors (TeraFETs) employing (i) AlGaN/GaN high-electron-mobility and (ii) silicon CMOS field-effect transistors and show that the super-linear behavior in the sub-threshold bias regime is a universal phenomenon to be expected if the amplitude of the high-frequency voltage oscillations exceeds the thermal voltage. The effect is also employed as a tool for the direct determination of the speed of the intrinsic TeraFET response which allows us to avoid limitations set by the read-out circuitry. In particular, we show that the build-up time of the intrinsic rectification signal of a patch-antenna-coupled CMOS detector changes from 20 ps in the deep sub-threshold voltage regime to below 12 ps in the vicinity of the threshold voltage.

  14. Structural, optical and electrical studies on pulse electrodeposited CdIn2S4 thin films

    International Nuclear Information System (INIS)

    Kokate, A.V.; Asabe, M.R.; Shelake, S.B.; Hankare, P.P.; Chougule, B.K.

    2007-01-01

    CdIn 2 S 4 thin films were prepared by pulse electrodeposition technique over F:SnO 2 glass and stainless steel substrates in galvanostatic mode from an aqueous acidic bath containing CdSO 4 , InCl 3 and Na 2 S 2 O 3 . The growth kinetics of the film has been studied and the deposition parameters such as electrolyte bath concentration, bath temperature, time of deposition, deposition current and pH of the bath are optimized. X-ray diffraction (XRD) analysis of the as deposited and annealed films shows polycrystalline nature. Energy dispersive analysis by X-ray (EDAX) confirms nearly stoichiometric CdIn 2 S 4 nature of the film. Scanning electron microscope (SEM) studies show that, the deposited films are well adherent and grains are uniformly distributed over the surface of the substrate. The optical transmission spectra show a direct band gap of 2.16 eV. Conductivity measurements have been carried out at different temperatures and electrical parameters such as activation energy, trapped energy state and barrier heights etc. have been determined

  15. Effects of Pulsed Electric Fields (PEF) on Vitamin C and Its Antioxidant Properties

    Science.gov (United States)

    Zhang, Zhi-Hong; Zeng, Xin-An; Brennan, Charles S.; Brennan, Margaret; Han, Zhong; Xiong, Xia-Yu

    2015-01-01

    In this study, pulsed electric fields (PEF) treatments and their effects on the structure of vitamin C (VIT-C) were estimated by fluorescence and Fourier transform infrared (FT-IR) spectroscopy, the relative content of VIT-C was measured by HPLC and the antioxidant properties of treated VIT-C by DPPH radical scavenging as well as reducing power tests. The fluorescence intensity of treated VIT-C increased slightly compared to the untreated VIT-C. Moreover, the effect of PEF on the structure of VIT-C was observed using the FT-IR spectra. These phenomena indicated that the PEF affected the conformation of VIT-C, which promoted the VIT-C isomer transformed enol-form into keto-form. In addition, the PEF treatments did not suffer the damage to VIT-C and could slow down the oxidation process in involving of experimental conditions by HPLC. The antioxidant properties of the treated VIT-C were enhanced, which was proved by radical scavenging and also the reducing power tests. PMID:26473846

  16. Effect of Pulsed Electric Field on Membrane Lipids and Oxidative Injury of Salmonella typhimurium.

    Science.gov (United States)

    Yun, Ou; Zeng, Xin-An; Brennan, Charles S; Han, Zhong

    2016-08-22

    Salmonella typhimurium cells were subjected to pulsed electric field (PEF) treatment at 25 kV/cm for 0-4 ms to investigate the effect of PEF on the cytoplasmic membrane lipids and oxidative injury of cells. Results indicated that PEF treatment induced a decrease of membrane fluidity of Salmonella typhimurium (S. typhimuriumi), possibly due to the alterations of fatty acid biosynthesis-associated gene expressions (down-regulation of cfa and fabA gene expressions and the up-regulation of fabD gene expression), which, in turn, modified the composition of membrane lipid (decrease in the content ratio of unsaturated fatty acids to saturated fatty acids). In addition, oxidative injury induced by PEF treatment was associated with an increase in the content of malondialdehyde. The up-regulation of cytochrome bo oxidase gene expressions (cyoA, cyoB, and cyoC) indicated that membrane damage was induced by PEF treatment, which was related to the repairing mechanism of alleviating the oxidative injury caused by PEF treatment. Based on these results, we achieved better understanding of microbial injury induced by PEF, suggesting that micro-organisms tend to decrease membrane fluidity in response to PEF treatment and, thus, a greater membrane fluidity might improve the efficiency of PEF treatment to inactivate micro-organisms.

  17. Pulsed electric field treatment enhanced stilbene content in Graciano, Tempranillo and Grenache grape varieties.

    Science.gov (United States)

    López-Alfaro, Isabel; González-Arenzana, Lucía; López, Noelia; Santamaría, Pilar; López, Rosa; Garde-Cerdán, Teresa

    2013-12-15

    The purpose of this paper was to study the effect of pulsed electric fields (PEF) on the stilbene content of three grape varieties. For this purpose, four different PEF treatments were applied using a continuous system over three varieties, Graciano, Tempranillo and Grenache, destemmed and crushed. In addition, the influence of PEF on their physicochemical composition was studied. PEF treatments did not affect the pH or total acidity of Graciano, however, musts from Tempranillo and Grenache had higher pH values and lower total acidity. In the three varieties, all treatments resulted in an increase of potassium content, deeper colour intensity and total polyphenol index and lower tonality, more pronounced in the treatments with higher time and energy. The stilbene content of the must significantly increased with respect to the control. This increase depended on the variety and the treatment applied. Tempranillo increased up 200% the total stilbene concentration, Grenache 60% and Graciano 50%. For the three varieties, the treatment with the highest time and energy was the most effective on the total stilbene extraction. These results indicate that PEF could be a suitable technology for obtaining musts with deeper colour and higher phenolic content, including resveratrol and piceid. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Pulsed electric field and combination processing of mango nectar: effect on volatile compounds and HMF formation

    Directory of Open Access Journals (Sweden)

    A. S. Bawa

    2015-01-01

    Full Text Available Mango nectar is a commercially familiar and preferred product. The traditional processing of mango nectar has been by thermal processing which resulted in the alteration of the flavour of the product due to the effect of high temperature. The thermal processing of the nectar also resulted in the production of byproducts of non-enzymatic browning such as 5- hydroxy methyl furfural (HMF. These process induced effects, affect both the nutritive and sensory attributes of the fruit product, making it less preferable. With the growing interest and awareness about the benefits of alternative non-thermal technologies, such as pulsed electric field (PEF, the present work was proposed to use PEF to minimize the loss of volatiles and formation of HMF. The study involves thermal (96 ºC for 300 s and 600 s, PEF (24 µs, 120 Hz and 38 kV/cm and combination processing (PEF + Thermal (96 ºC for 90 s of mango nectar. The effect of these treatments on the volatile composition of mango nectar has been analysed using GC-MS technique. The reduction in the volatile compounds was significant (p 0.05 different from unprocessed sample, proving the fresh-like character of the product.

  19. Effect of various gases and chemical catalysts on phenol degradation pathways by pulsed electrical discharges

    International Nuclear Information System (INIS)

    Shen Yongjun; Lei Lecheng; Zhang Xingwang; Zhou Minghua; Zhang Yi

    2008-01-01

    The processes of phenol degradation by pulsed electrical discharges were investigated under several kinds of discharge atmospheres (oxygen, argon, nitrogen and ozone) and chemical catalysts (ferrous ion and hydrogen peroxide). The temporal variations of the concentrations of phenol and the intermediate products were monitored by HPLC and GC-MS, respectively. It has been found that the effect of various gases bubbling on phenol degradation rate ranked in the following order: oxygen-containing ozone > oxygen > argon > nitrogen. The high gas bubbling flow rate was beneficial to the removal of phenol. It was found that the degradation proceeded differently when in the presence and absence of catalysts. The phenol removal rate was increased when ferrous ion was added. This considerable enhancement may be due to the Fenton's reaction. What's more, putting the chemical additives hydrogen peroxide into the reactor led to a dramatic increase in phenol degradation rate. The mechanism was due to the direct or indirect photolysis and pyrolysis destruction in plasma channel. Furthermore, the intermediate products were monitored by GC-MS under three degradation conditions. More THBs were generated under degradation conditions without gases bubbling or adding any catalyst, and more DHBs under the condition of adding ferrous ion, and more carboxylic acids under the condition of oxygen-containing ozone gas bubbling. Consequently, three distinct degradation pathways based on different conditions were proposed

  20. Effects of Pulsed Electric Fields (PEF on Vitamin C and Its Antioxidant Properties

    Directory of Open Access Journals (Sweden)

    Zhi-Hong Zhang

    2015-10-01

    Full Text Available In this study, pulsed electric fields (PEF treatments and their effects on the structure of vitamin C (VIT-C were estimated by fluorescence and Fourier transform infrared (FT-IR spectroscopy, the relative content of VIT-C was measured by HPLC and the antioxidant properties of treated VIT-C by DPPH radical scavenging as well as reducing power tests. The fluorescence intensity of treated VIT-C increased slightly compared to the untreated VIT-C. Moreover, the effect of PEF on the structure of VIT-C was observed using the FT-IR spectra. These phenomena indicated that the PEF affected the conformation of VIT-C, which promoted the VIT-C isomer transformed enol-form into keto-form. In addition, the PEF treatments did not suffer the damage to VIT-C and could slow down the oxidation process in involving of experimental conditions by HPLC. The antioxidant properties of the treated VIT-C were enhanced, which was proved by radical scavenging and also the reducing power tests.

  1. Generic functional modelling of multi-pulse auto-transformer rectifier units for more-electric aircraft applications

    Directory of Open Access Journals (Sweden)

    Tao YANG

    2018-05-01

    Full Text Available The Auto-Transformer Rectifier Unit (ATRU is one preferred solution for high-power AC/DC power conversion in aircraft. This is mainly due to its simple structure, high reliability and reduced kVA ratings. Indeed, the ATRU has become a preferred AC/DC solution to supply power to the electric environment control system on-board future aircraft. In this paper, a general modelling method for ATRUs is introduced. The developed model is based on the fact that the DC voltage and current are strongly related to the voltage and current vectors at the AC terminals of ATRUs. In this paper, we carry on our research in modelling symmetric 18-pulse ATRUs and develop a generic modelling technique. The developed generic model can study not only symmetric but also asymmetric ATRUs. An 18-pulse asymmetric ATRU is used to demonstrate the accuracy and efficiency of the developed model by comparing with corresponding detailed switching SABER models provided by our industrial partner. The functional models also allow accelerated and accurate simulations and thus enable whole-scale more-electric aircraft electrical power system studies in the future. Keywords: Asymmetric transformer, Functional modelling, More-Electric Aircraft, Multi-pulse rectifier, Transformer rectifier unit

  2. Detection of Alkylating Agents using Electrical and Mechanical Means

    Science.gov (United States)

    Gerchikov, Yulia; Borzin, Elena; Gannot, Yair; Shemesh, Ariel; Meltzman, Shai; Hertzog-Ronen, Carmit; Tal, Shay; Stolyarova, Sara; Nemirovsky, Yael; Tessler, Nir; Eichen, Yoav

    2011-08-01

    Alkylating agents are reactive molecules having at least one polar bond between a carbon atom and a good leaving group. These often simple molecules are frequently used in organic synthesis, as sterilizing agents in agriculture and even as anticancer agents in medicine. Unfortunately, for over a century, some of the highly reactive alkylating agents are also being used as blister chemical warfare agents. Being relatively simple to make, the risk is that these will be applied by terrorists as poor people warfare agents. The detection and identification of such alkylating agents is not a simple task because of their high reactivity and simple structure of the reactive site. Here we report on new approaches to the detection and identification of such alkylating agents using electrical (organic field effect transistors) and mechanical (microcantilevers) means.

  3. Detection of Alkylating Agents using Electrical and Mechanical Means

    International Nuclear Information System (INIS)

    Gerchikov, Yulia; Borzin, Elena; Gannot, Yair; Shemesh, Ariel; Meltzman, Shai; Hertzog-Ronen, Carmit; Eichen, Yoav; Tal, Shay; Stolyarova, Sara; Nemirovsky, Yael; Tessler, Nir

    2011-01-01

    Alkylating agents are reactive molecules having at least one polar bond between a carbon atom and a good leaving group. These often simple molecules are frequently used in organic synthesis, as sterilizing agents in agriculture and even as anticancer agents in medicine. Unfortunately, for over a century, some of the highly reactive alkylating agents are also being used as blister chemical warfare agents. Being relatively simple to make, the risk is that these will be applied by terrorists as poor people warfare agents. The detection and identification of such alkylating agents is not a simple task because of their high reactivity and simple structure of the reactive site. Here we report on new approaches to the detection and identification of such alkylating agents using electrical (organic field effect transistors) and mechanical (microcantilevers) means.

  4. Detection of Alkylating Agents using Electrical and Mechanical Means

    Energy Technology Data Exchange (ETDEWEB)

    Gerchikov, Yulia; Borzin, Elena; Gannot, Yair; Shemesh, Ariel; Meltzman, Shai; Hertzog-Ronen, Carmit; Eichen, Yoav [Schulich Department of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa (Israel) (Israel); Tal, Shay [Present address: Systems Biology Department, Harvard Medical School, Boston, MA 02115 (United States); Stolyarova, Sara; Nemirovsky, Yael; Tessler, Nir, E-mail: chryoav@tx.technion.ac.il [Department of Electrical Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa (Israel)

    2011-08-17

    Alkylating agents are reactive molecules having at least one polar bond between a carbon atom and a good leaving group. These often simple molecules are frequently used in organic synthesis, as sterilizing agents in agriculture and even as anticancer agents in medicine. Unfortunately, for over a century, some of the highly reactive alkylating agents are also being used as blister chemical warfare agents. Being relatively simple to make, the risk is that these will be applied by terrorists as poor people warfare agents. The detection and identification of such alkylating agents is not a simple task because of their high reactivity and simple structure of the reactive site. Here we report on new approaches to the detection and identification of such alkylating agents using electrical (organic field effect transistors) and mechanical (microcantilevers) means.

  5. Defining treatment conditions for pulsed electric field pasteurization of apple juice.

    Science.gov (United States)

    Saldaña, G; Puértolas, E; Monfort, S; Raso, J; Alvarez, I

    2011-11-15

    The influence of temperature and the presence of N(α)-lauroyl ethylester (ethyl lauroyl arginate, LAE) on the inactivation caused by continuous pulsed electric field treatments (PEF) in Escherichia coli O157:H7 suspended in apple juice have been investigated to define treatment conditions applicable at industrial scale that promote an equivalent safety level when compared with thermal processing. In the range of experimental conditions investigated (outlet temperature: 20-40 °C, electric field strength: 20-30 kV, treatment time: 5-125 μs) at outlet temperatures equal or lower than 55±1 °C, the inactivation of E. coli O157:H7 treated in apple juice ranged from 0.4 to 3.6 Log₁₀ cycles reduction and treated in apple juice supplemented with LAE (50 ppm) ranged from 0.9 to 6.7 Log₁₀ cycles reduction. An empirical mathematical model was developed to estimate the treatment time and total specific energy input to obtain 5 Log₁₀ cycles reduction in the population of E. coli O157:H7 suspended in apple juice supplemented with 50 ppm of LAE at different electric field strengths and inlet temperatures. Treatment conditions established for E. coli O157:H7 were validated with other PEF resistant Gram-positive (Listeria monocytogenes, and Staphylococcus aureus) and Gram-negative (Salmonella enterica serovar Typhimurium) strains. When the treatment was applied to the apple juice, a treatment of 25 kV/cm for 63 μs corresponding with an outlet temperature of 65 °C and input energy of 125 kJ/kg was required to achieve more than 5 Log₁₀ cycles in the four strains investigated. The addition of LAE reduced the treatment time required to obtain an equivalent inactivation (>5 Log₁₀ cycles) in the four microorganisms to 38.4 μs, the outlet temperature to 55 °C, and the input energy to 83.2 kJ/kg. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Soft-Fault Detection Technologies Developed for Electrical Power Systems

    Science.gov (United States)

    Button, Robert M.

    2004-01-01

    The NASA Glenn Research Center, partner universities, and defense contractors are working to develop intelligent power management and distribution (PMAD) technologies for future spacecraft and launch vehicles. The goals are to provide higher performance (efficiency, transient response, and stability), higher fault tolerance, and higher reliability through the application of digital control and communication technologies. It is also expected that these technologies will eventually reduce the design, development, manufacturing, and integration costs for large, electrical power systems for space vehicles. The main focus of this research has been to incorporate digital control, communications, and intelligent algorithms into power electronic devices such as direct-current to direct-current (dc-dc) converters and protective switchgear. These technologies, in turn, will enable revolutionary changes in the way electrical power systems are designed, developed, configured, and integrated in aerospace vehicles and satellites. Initial successes in integrating modern, digital controllers have proven that transient response performance can be improved using advanced nonlinear control algorithms. One technology being developed includes the detection of "soft faults," those not typically covered by current systems in use today. Soft faults include arcing faults, corona discharge faults, and undetected leakage currents. Using digital control and advanced signal analysis algorithms, we have shown that it is possible to reliably detect arcing faults in high-voltage dc power distribution systems (see the preceding photograph). Another research effort has shown that low-level leakage faults and cable degradation can be detected by analyzing power system parameters over time. This additional fault detection capability will result in higher reliability for long-lived power systems such as reusable launch vehicles and space exploration missions.

  7. Sensitive and ultra-fast species detection using pulsed cavity ringdown spectroscopy

    KAUST Repository

    Alquaity, Awad

    2015-01-01

    Pulsed cavity ringdown spectroscopy (CRDS) is used to develop a novel, ultra-fast, high-sensitivity diagnostic for measuring species concentrations in shock tube experiments. The diagnostic is demonstrated by monitoring trace concentrations of ethylene in the mid-IR region near 949.47 cm-1. Each ringdown measurement is completed in less than 1 μs and the time period between successive pulses is 10 μs. The high sensitivity diagnostic has a noise-equivalent detection limit of 1.08 x 10-5 cm-1 which enables detection of 15 ppm ethylene at fuel pyrolysis conditions (1845 K and 2 bar) and 294 ppb ethylene under ambient conditions (297 K and 1 bar). To our knowledge, this is the first successful application of the cavity ringdown method to the measurement of species time-histories in a shock tube. © 2015 OSA.

  8. Electrical detection of cellular penetration during microinjection with carbon nanopipettes

    Science.gov (United States)

    Anderson, Sean E.; Bau, Haim H.

    2014-06-01

    The carbon nanopipette (CNP) is comprised of a pulled-glass pipette terminating with a nanoscale (tens to hundreds of nm) diameter carbon pipe. The entire inner glass surface of the CNP is coated with a carbon film, providing an electrically conductive path from the carbon tip to the distal, macroscopic end of the pipette. The CNP can double as a nanoelectrode, enabling electrical measurements through its carbon lining, and as a nanoinjector, facilitating reagent injection through its hollow bore. With the aid of a lock-in amplifier, we measured, in real time and with millisecond resolution, variations in impedance and interfacial capacitance as the CNP penetrated into the cytoplasm and nucleus of adherent human osteosarcoma (U20S) cells during microinjection. The capacitance change associated with nucleus penetration was, on average, 1.5 times greater than the one associated with cell membrane penetration. The experimental data was compared and favorably agreed with theoretical predictions based on a simple electrical network model. As a proof of concept, the cytoplasm and nucleus were transfected with fluorescent tRNA, enabling real-time monitoring of tRNA trafficking across the nuclear membrane. The CNP provides a robust and reliable means to detect cell and nucleus penetration, and trigger injection, thereby enabling the automation of cell injection.

  9. Electrical detection of cellular penetration during microinjection with carbon nanopipettes

    International Nuclear Information System (INIS)

    Anderson, Sean E; Bau, Haim H

    2014-01-01

    The carbon nanopipette (CNP) is comprised of a pulled-glass pipette terminating with a nanoscale (tens to hundreds of nm) diameter carbon pipe. The entire inner glass surface of the CNP is coated with a carbon film, providing an electrically conductive path from the carbon tip to the distal, macroscopic end of the pipette. The CNP can double as a nanoelectrode, enabling electrical measurements through its carbon lining, and as a nanoinjector, facilitating reagent injection through its hollow bore. With the aid of a lock-in amplifier, we measured, in real time and with millisecond resolution, variations in impedance and interfacial capacitance as the CNP penetrated into the cytoplasm and nucleus of adherent human osteosarcoma (U20S) cells during microinjection. The capacitance change associated with nucleus penetration was, on average, 1.5 times greater than the one associated with cell membrane penetration. The experimental data was compared and favorably agreed with theoretical predictions based on a simple electrical network model. As a proof of concept, the cytoplasm and nucleus were transfected with fluorescent tRNA, enabling real-time monitoring of tRNA trafficking across the nuclear membrane. The CNP provides a robust and reliable means to detect cell and nucleus penetration, and trigger injection, thereby enabling the automation of cell injection. (papers)

  10. A model of preliminary breakdown pulse peak currents and their relation to the observed electric-field pulses

    Czech Academy of Sciences Publication Activity Database

    Kašpar, Petr; Santolík, Ondřej; Kolmašová, Ivana; Farges, T.

    2017-01-01

    Roč. 44, č. 1 (2017), s. 596-603 ISSN 0094-8276 R&D Projects: GA ČR(CZ) GA14-31899S Grant - others:AV ČR(CZ) AP1401 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:68378289 Keywords : lightning initiation * electromagnetic radiation * preliminary breakdown pulses Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 4.253, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/2016GL071483/pdf

  11. First day of life pulse oximetry screening to detect congenital heart defects.

    Science.gov (United States)

    Meberg, Alf; Brügmann-Pieper, Sabine; Due, Reidar; Eskedal, Leif; Fagerli, Ingebjørg; Farstad, Teresa; Frøisland, Dag Helge; Sannes, Catharina Hovland; Johansen, Ole Jakob; Keljalic, Jasmina; Markestad, Trond; Nygaard, Egil Andre; Røsvik, Alet; Silberg, Inger Elisabeth

    2008-06-01

    To evaluate the efficacy of first day of life pulse oximetry screening to detect congenital heart defects (CHDs). We performed a population-based prospective multicenter study of postductal (foot) arterial oxygen saturation (SpO(2)) in apparently healthy newborns after transfer from the delivery suite to the nursery. SpO(2) < 95% led to further diagnostic evaluations. Of 57,959 live births, 50,008 (86%) were screened. In the screened population, 35 CHDs were [corrected] classified as critical (ductus dependent, cyanotic). CHDs were prospectively registered and diagnosed in 658/57,959 (1.1%) [corrected] Of the infants screened, 324 (0.6%) failed the test. Of these, 43 (13%) had CHDs (27 critical), and 134 (41%) had pulmonary diseases or other disorders. The remaining 147 infants (45%) were healthy with transitional circulation. The median age for babies with CHDs at failing the test was 6 hours (range, 1-21 hours). For identifying critical CHDs, the pulse oximetry screening had a sensitivity rate of 77.1% (95% CI, 59.4-89.0), specificity rate of 99.4% (95% CI, 99.3-99.5), and a false-positive rate of 0.6% (95% CI, 0.5-0.7). Early pulse oximetry screening promotes early detection of critical CHDs and other potentially severe diseases. The sensitivity rate for detecting critical CHDs is high, and the false-positive rate is low.

  12. Study on Analysis and Pattern Recognition of the Manifestation of the Pulse Detection of Cerebrovascular Disease

    Energy Technology Data Exchange (ETDEWEB)

    Jing, J; Wang, Y C; Hong, W X; Zhang, W P [Department of Biomedical Engineering, University of Yanshan, Qinhuangdao, Hebei Province, 066004 (China)

    2006-10-15

    Cerebrovascular Disease (CVD) is also called stroke in Traditional Chinese Medicine (TCM). CVD is a kind of frequent diseases with high incidence, high death rate, high deformity rate and high relapse rate. The pathogenesis of CVD has relation to many factors. In modern medicine, we can make use of various instruments to check many biochemical parameters. However, at present, the early detection of CVD can mostly be done artificially by specialists. In TCM the salted expert can detect the state of a CVD patient by felling his (or her) pulse. It is significant to apply the modern information and engineering techniques to the early discovery of CVD. It is also a challenge to do this in fact. In this paper, the authors presented a detection method of CVD basing on analysis and pattern recognition of Manifestation of the Pulse of TCM using wavelet technology and Neural Networks. Pulse signals from normal health persons and CVD patients were studied comparatively. This research method is flexible to deal with other physiological signals.

  13. A frequency and pulse-width co-modulation strategy for transcutaneous neuromuscular electrical stimulation based on sEMG time-domain features

    Science.gov (United States)

    Zhou, Yu-Xuan; Wang, Hai-Peng; Bao, Xue-Liang; Lü, Xiao-Ying; Wang, Zhi-Gong

    2016-02-01

    Objective. Surface electromyography (sEMG) is often used as a control signal in neuromuscular electrical stimulation (NMES) systems to enhance the voluntary control and proprioceptive sensory feedback of paralyzed patients. Most sEMG-controlled NMES systems use the envelope of the sEMG signal to modulate the stimulation intensity (current amplitude or pulse width) with a constant frequency. The aims of this study were to develop a strategy that co-modulates frequency and pulse width based on features of the sEMG signal and to investigate the torque-reproduction performance and the level of fatigue resistance achieved with our strategy. Approach. We examined the relationships between wrist torque and two stimulation parameters (frequency and pulse width) and between wrist torque and two sEMG time-domain features (mean absolute value (MAV) and number of slope sign changes (NSS)) in eight healthy volunteers. By using wrist torque as an intermediate variable, customized and generalized transfer functions were constructed to convert the two features of the sEMG signal into the two stimulation parameters, thereby establishing a MAV/NSS dual-coding (MNDC) algorithm. Wrist torque reproduction performance was assessed by comparing the torque generated by the algorithms with that originally recorded during voluntary contractions. Muscle fatigue was assessed by measuring the decline percentage of the peak torque and by comparing the torque time integral of the response to test stimulation trains before and after fatigue sessions. Main Results. The MNDC approach could produce a wrist torque that closely matched the voluntary wrist torque. In addition, a smaller decay in the wrist torque was observed after the MNDC-coded fatigue stimulation was applied than after stimulation using pulse-width modulation alone. Significance. Compared with pulse-width modulation stimulation strategies that are based on sEMG detection, the MNDC strategy is more effective for both voluntary muscle

  14. Transient Sensory Recovery in Stroke Patients After Pulsed Radiofrequency Electrical Stimulation on Dorsal Root Ganglia: A Case Series.

    Science.gov (United States)

    Apiliogullari, Seza; Gezer, Ilknur A; Levendoglu, Funda

    2017-01-01

    The integrity of the somatosensory system is important for motor recovery and neuroplasticity after strokes. Peripheral stimulation or central stimulation in patients with central nervous system lesions can be an effective modality in improving function and in facilitating neuroplasticity. We present 2 hemiplegic cases with sensory motor deficit and the result of the pulsed radiofrequency (PRF) electrical stimulation to the dorsal root ganglia. After PRF electrical stimulation, significant improvement was achieved in the examination of patients with superficial and deep sensation. However, during the follow-up visits were observed that the effect of PRF electrical stimulation disappeared. We believe that these preliminary results could be used in the development of future prospective cohort studies and randomized controlled trials that focus on the effect of PRF electrical stimulation on dorsal root ganglia to treat sensory deficits in poststroke patients.

  15. Comparison of electric dipole and magnetic dipole models for electromagnetic pulse generated by nuclear detonation in space

    International Nuclear Information System (INIS)

    Zhu Meng; Zhou Hui; Cheng Yinhui; Li Baozhong; Wu Wei; Li Jinxi; Ma Liang; Zhao Mo

    2013-01-01

    Electromagnetic pulse can be generated by the nuclear detonation in space via two radiation mechanisms. The electric dipole and magnetic dipole models were analyzed. The electric radiation in the far field generated by two models was calculated as well. Investigations show that in the case of one hundred TNT yield detonations, when electrons are emitted according to the Gaussian shape, two radiation models can give rise to the electric field in great distances with amplitudes of kV/m and tens of V/m, independently. Because the geomagnetic field in space is not strong and the electrons' angular motion is much weaker than the motion in the original direction, radiations from the magnetic dipole model are much weaker than those from the electric dipole model. (authors)

  16. Detection of questionable occlusal carious lesions using an electrical bioimpedance method with fractional electrical model

    Energy Technology Data Exchange (ETDEWEB)

    Morais, A. P. [Biomedical Engineering Program, COPPE, Rio de Janeiro (Brazil); Salgado de Oliveira University, Marechal Deodoro Street, 217 – Centro, Niterói, Rio de Janeiro (Brazil); Pino, A. V. [Biomedical Engineering Program, COPPE, Rio de Janeiro (Brazil); Souza, M. N. [Biomedical Engineering Program, COPPE, Rio de Janeiro (Brazil); Electronics Department at Polytechnic School, Federal University of Rio de Janeiro, Centro de Tecnologia Bloco H sala 217, Ilha do Fundão, Rio de Janeiro (Brazil)

    2016-08-15

    This in vitro study evaluated the diagnostic performance of an alternative electric bioimpedance spectroscopy technique (BIS-STEP) detect questionable occlusal carious lesions. Six specialists carried out the visual (V), radiography (R), and combined (VR) exams of 57 sound or non-cavitated occlusal carious lesion teeth classifying the occlusal surfaces in sound surface (H), enamel caries (EC), and dentinal caries (DC). Measurements were based on the current response to a step voltage excitation (BIS-STEP). A fractional electrical model was used to predict the current response in the time domain and to estimate the model parameters: Rs and Rp (resistive parameters), and C and α (fractional parameters). Histological analysis showed caries prevalence of 33.3% being 15.8% hidden caries. Combined examination obtained the best traditional diagnostic results with specificity = 59.0%, sensitivity = 70.9%, and accuracy = 60.8%. There were statistically significant differences in bioimpedance parameters between the H and EC groups (p = 0.016) and between the H and DC groups (Rs, p = 0.006; Rp, p = 0.022, and α, p = 0.041). Using a suitable threshold for the Rs, we obtained specificity = 60.7%, sensitivity = 77.9%, accuracy = 73.2%, and 100% of detection for deep lesions. It can be concluded that BIS-STEP method could be an important tool to improve the detection and management of occlusal non-cavitated primary caries and pigmented sites.

  17. Detection of questionable occlusal carious lesions using an electrical bioimpedance method with fractional electrical model

    International Nuclear Information System (INIS)

    Morais, A. P.; Pino, A. V.; Souza, M. N.

    2016-01-01

    This in vitro study evaluated the diagnostic performance of an alternative electric bioimpedance spectroscopy technique (BIS-STEP) detect questionable occlusal carious lesions. Six specialists carried out the visual (V), radiography (R), and combined (VR) exams of 57 sound or non-cavitated occlusal carious lesion teeth classifying the occlusal surfaces in sound surface (H), enamel caries (EC), and dentinal caries (DC). Measurements were based on the current response to a step voltage excitation (BIS-STEP). A fractional electrical model was used to predict the current response in the time domain and to estimate the model parameters: Rs and Rp (resistive parameters), and C and α (fractional parameters). Histological analysis showed caries prevalence of 33.3% being 15.8% hidden caries. Combined examination obtained the best traditional diagnostic results with specificity = 59.0%, sensitivity = 70.9%, and accuracy = 60.8%. There were statistically significant differences in bioimpedance parameters between the H and EC groups (p = 0.016) and between the H and DC groups (Rs, p = 0.006; Rp, p = 0.022, and α, p = 0.041). Using a suitable threshold for the Rs, we obtained specificity = 60.7%, sensitivity = 77.9%, accuracy = 73.2%, and 100% of detection for deep lesions. It can be concluded that BIS-STEP method could be an important tool to improve the detection and management of occlusal non-cavitated primary caries and pigmented sites.

  18. Yeast cell inactivation related to local heating induced by low-intensity electric fields with long-duration pulses.

    Science.gov (United States)

    Guyot, Stéphane; Ferret, Eric; Boehm, Jean-Baptiste; Gervais, Patrick

    2007-01-25

    The effects of electric field (EF) treatments on Saccharomyces cerevisiae viability were investigated using a PG200 electroporator (Hoefer Scientific Instrument, San Fransisco, CA, USA) with specific attention to induced thermal effects on cell death. Lethal electric fields (1.5 kV cm(-1) for 5 s) were shown to cause heat variations in the cell suspension medium (water+glycerol), while corresponding classical thermal treatments at equivalent temperatures had no effect on the cells viability. Variations of the electrical conductivity of the intra- and extracellular matrix caused by ions and solutes transfer across the membrane were shown to be involved in the observed heating. The results permitted to build a theoretical model for the temperature variations induced by electric fields. Using this model and the electrical conductivity of the different media, a plausible explanation of the cell death induced by low-intensity electric fields with long-duration pulses has been proposed. Indeed, cell mortality could in part be caused by direct and indirect effects of electric fields. Direct effects are related to well known electromechanical phenomena, whereas indirect effects are related to secondary thermal stress caused by plasma membrane thermoporation. This thermoporation was attributed to electrical conductivity variations and the corresponding intracellular heating.

  19. Effect of high-intensity pulsed electric fields processing and conventional heat treatment on orange-carrot juice carotenoids.

    Science.gov (United States)

    Torregrosa, Francisco; Cortés, Clara; Esteve, María J; Frígola, Ana

    2005-11-30

    Liquid chromatography (LC) was the method of choice for quantification of carotenoids (including geometrical isomers) to evaluate the effects of high-intensity pulsed electric field (HIPEF), a nonthermal preservation method, with different parameters (electric field intensities and treatment times), on an orange-carrot juice mixture (80:20, v/v). In parallel, a conventional heat treatment (98 degrees C, 21 s) was applied to the juice. HIPEF processing generally caused a significant increase in the concentrations of the carotenoids identified as treatment time increased. HIPEF treatment at 25 and 30 kV/cm provided a vitamin A concentration higher than that found in the pasteurized juice.

  20. Pulse mode of operation of a spherical piezoceramic transducer filled with liquid and having a correcting electric circuit.

    Science.gov (United States)

    Konovalov, S I; Kuz'menko, A G

    2010-12-01

    By means of a computational method, the possibility of radiating a short acoustic pulse by a transducer in the form of a piezoceramic sphere internally filled with liquid is investigated. An electric inductive-resistive circuit is connected to the electric input of the transducer. Solution is obtained based on scheme-analogs theory for piezoceramic transducers, and spectral Fourier transform theory. The values of parameters of the system, providing minimal durations of radiated signals, are determined. Computation was carried out for different values of relative thicknesses of the transducer wall. The estimates of durations and amplitudes of the acoustic signals radiated into the external medium are obtained.

  1. Single attosecond pulse generation in an orthogonally polarized two-color laser field combined with a static electric field

    International Nuclear Information System (INIS)

    Xia Changlong; Zhang Gangtai; Wu Jie; Liu Xueshen

    2010-01-01

    We investigate theoretic high-order harmonic generation and single attosecond pulse generation in an orthogonally polarized two-color laser field, which is synthesized by a mid-infrared (IR) pulse (12.5 fs, 2000 nm) in the y component and a much weaker (12 fs, 800 nm) pulse in the x component. We find that the width of the harmonic plateau can be extended when a static electric field is added in the y component. We also investigate emission time of harmonics in terms of a time-frequency analysis to illustrate the physical mechanism of high-order harmonic generation. We calculate the ionization rate using the Ammosov-Delone-Krainov model and interpret the variation of harmonic intensity for different static electric field strengths. When the ratio of strengths of the static and the y-component laser fields is 0.1, a continuous harmonic spectrum is formed from 220 to 420 eV. By superposing a properly selected range of the harmonic spectrum from 300 to 350 eV, an isolated attosecond pulse with a duration of about 75 as is obtained, which is near linearly polarized.

  2. Metabolite profiling of phenolic and carotenoid contents in tomatoes after moderate-intensity pulsed electric field treatments.

    Science.gov (United States)

    Vallverdú-Queralt, Anna; Oms-Oliu, Gemma; Odriozola-Serrano, Isabel; Lamuela-Raventós, Rosa M; Martín-Belloso, Olga; Elez-Martínez, Pedro

    2013-01-01

    A metabolite profiling approach was used to study the effect of moderate-intensity pulsed electric field (MIPEF) treatments on the individual polyphenol and carotenoid contents of tomato fruit after refrigeration at 4°C for 24h. The MIPEF processing variables studied were electric field strength (from 0.4 to 2.0kV/cm) and number of pulses (from 5 to 30). Twenty four hours after MIPEF treatments, an increase was observed in hydroxycinnamic acids and flavanones, whereas flavonols, coumaric and ferulic acid-O-glucoside were not affected. Major changes were also observed for carotenoids, except for the 5-cis-lycopene isomer, which remain unchanged after 24h of MIPEF treatments. MIPEF treatments, conducted at 1.2kV/cm and 30 pulses, led to the greatest increases in chlorogenic (152%), caffeic acid-O-glucoside (170%) and caffeic (140%) acids. On the other hand, treatments at 1.2kV/cm and 5 pulses led to maximum increases of α-carotene, 9- and 13-cis-lycopene, which increased by 93%, 94% and 140%, respectively. Therefore, MIPEF could stimulate synthesis of secondary metabolites and contribute to production of tomatoes with high individual polyphenol and carotenoid contents. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Change in Color and Volatile Composition of Skim Milk Processed with Pulsed Electric Field and Microfiltration Treatments or Heat Pasteurization

    OpenAIRE

    Chugh, Anupam; Khanal, Dipendra; Walkling-Ribeiro, Markus; Corredig, Milena; Duizer, Lisa; Griffiths, Mansel

    2014-01-01

    Non-thermal processing methods, such as pulsed electric field (PEF) and tangential-flow microfiltration (TFMF), are emerging processing technologies that can minimize the deleterious effects of high temperature short time (HTST) pasteurization on quality attributes of skim milk. The present study investigates the impact of PEF and TFMF, alone or in combination, on color and volatile compounds in skim milk. PEF was applied at 28 or 40 kV/cm for 1122 to 2805 µs, while microfiltration (MF) was c...

  4. Testing of Commercial Milk Production Technology Using A Combination of High Temperature Short Time and Pulsed Electric Field

    OpenAIRE

    Hadi A; Widjanarko SB; Kusnadi J

    2016-01-01

    The development of milk processing technology has grown excessively, and it contains advantage and disadvantage. This study used mixed between PEF (Pulsed Electric Field) and High Temperature Short Time (HTST) to produce milk processed product which is effective and efficient in killing milk microorganism without changing its color, scent, and nutrient content of processed product, therefore producing commercial sterile milk product in accord with milk Indonesian National Standard (SNI). The ...

  5. YAP scintillators for resonant detection of epithermal neutrons at pulsed neutron sources

    International Nuclear Information System (INIS)

    Tardocchi, M.; Gorini, G.; Pietropaolo, A.; Andreani, C.; Senesi, R.; Rhodes, N.; Schooneveld, E. M.

    2004-01-01

    Recent studies indicate the resonance detector (RD) technique as an interesting approach for neutron spectroscopy in the electron volt energy region. This work summarizes the results of a series of experiments where RD consisting of YAlO 3 (YAP) scintillators were used to detect scattered neutrons with energy in the range 1-200 eV. The response of YAP scintillators to radiative capture γ emission from a 238 U analyzer foil was characterized in a series of experiments performed on the VESUVIO spectrometer at the ISIS pulsed neutron source. In these experiments a biparametric data acquisition allowed the simultaneous measurements of both neutron time-of-flight and γ pulse height (energy) spectra. The analysis of the γ pulse height and neutron time of flight spectra permitted to identify and distinguish the signal and background components. These measurements showed that a significant improvement in the signal-to-background ratio can be achieved by setting a lower level discrimination on the pulse height at about 600 keV equivalent photon energy. Present results strongly indicate YAP scintillators as the ideal candidate for neutron scattering studies with epithermal neutrons at both very low (<5 deg.) and intermediate scattering angles

  6. Pulsed Electric Field inactivation of microbial cells: the use of ceramic layers to increase the efficiency of treatment

    International Nuclear Information System (INIS)

    Pizzichemi, M.

    2009-01-01

    The impact of Pulsed Electric Fields (PEF) on bacteria and plant or animal cells has been investigated since the early 1960s. High electric fields pulses (20-70 kV/cm, 1-10 μs) are reported to cause rupture of the cellular lipid membrane, through the mechanism of irreversible electroporation. Quantitative description of cell inactivation kinetics is based on the analysis of stability of lipid bilayers under electric fields and the thermal fluctuations associated with the production of pores. PEF has been successfully applied to inactivation of both Gram-positive and Gram-negative bacteria in many sorts of liquids, such as milk, fruit juices and liquid eggs. In all these media, the level of inactivation could reach the 5 Logs for an approximate range of pulses of 100-200, and an energy consumption of ∼ 10-100 kJ/kg. The advantages of PEF are the superior maintenance of functional and nutritional levels (if compared to traditional thermal treatment), continuous treatment and short processing times, while the current high costs of this technique make it more suitable for treatment of expensive media. We present a solution to the problem of volumes in PEF treatment through the use of high permittivity ceramics, while retaining the same inactivation efficiency and improving the duration of the electrodes.

  7. Pulsed Electric Field inactivation of microbial cells: the use of ceramic layers to increase the efficiency of treatment

    Science.gov (United States)

    Pizzichemi, M.

    2009-12-01

    The impact of Pulsed Electric Fields (PEF) on bacteria and plant or animal cells has been investigated since the early 1960s. High electric fields pulses (20-70 kV/cm, 1-10 μs) are reported to cause rupture of the cellular lipid membrane, through the mechanism of irreversible electroporation. Quantitative description of cell inactivation kinetics is based on the analysis of stability of lipid bilayers under electric fields and the thermal fluctuations associated with the production of pores. PEF has been successfully applied to inactivation of both Gram-positive and Gram-negative bacteria in many sorts of liquids, such as milk, fruit juices and liquid eggs. In all these media, the level of inactivation could reach the 5 Logs for an approximate range of pulses of 100-200, and an energy consumption of ˜ 10-100 kJ/kg. The advantages of PEF are the superior maintenance of functional and nutritional levels (if compared to traditional thermal treatment), continuous treatment and short processing times, while the current high costs of this technique make it more suitable for treatment of expensive media. We present a solution to the problem of volumes in PEF treatment through the use of high permittivity ceramics, while retaining the same inactivation efficiency and improving the duration of the electrodes.

  8. Pulsed Electric Field inactivation of microbial cells: the use of ceramic layers to increase the efficiency of treatment

    Energy Technology Data Exchange (ETDEWEB)

    Pizzichemi, M. [Physics Department, University of Milano - Bicocca (Italy)

    2009-12-15

    The impact of Pulsed Electric Fields (PEF) on bacteria and plant or animal cells has been investigated since the early 1960s. High electric fields pulses (20-70 kV/cm, 1-10 mus) are reported to cause rupture of the cellular lipid membrane, through the mechanism of irreversible electroporation. Quantitative description of cell inactivation kinetics is based on the analysis of stability of lipid bilayers under electric fields and the thermal fluctuations associated with the production of pores. PEF has been successfully applied to inactivation of both Gram-positive and Gram-negative bacteria in many sorts of liquids, such as milk, fruit juices and liquid eggs. In all these media, the level of inactivation could reach the 5 Logs for an approximate range of pulses of 100-200, and an energy consumption of approx 10-100 kJ/kg. The advantages of PEF are the superior maintenance of functional and nutritional levels (if compared to traditional thermal treatment), continuous treatment and short processing times, while the current high costs of this technique make it more suitable for treatment of expensive media. We present a solution to the problem of volumes in PEF treatment through the use of high permittivity ceramics, while retaining the same inactivation efficiency and improving the duration of the electrodes.

  9. Effect of high intensity pulsed electric fields and heat treatments on vitamins of milk.

    Science.gov (United States)

    Bendicho, Silvia; Espachs, Alexandre; Arántegui, Javier; Martín, Olga

    2002-02-01

    The effects of high intensity pulsed electric field (HIPEF) treatments at room or moderate temperature on water-soluble (thiamine, riboflavin, ascorbic acid) and fat-soluble vitamins (cholecalciferol and tocopherol) were evaluated and compared with conventional thermal treatments. Vitamin retention was determined in two different substrates, milk and simulated skim milk ultrafiltrate (SMUF). Samples were subjected to HIPEF treatments of up to 400 micros at field strengths from 18.3 to 27.1 kV/cm and to heat treatments of up to 60 min at temperatures from 50 to 90 degrees C. No changes in vitamin content were observed after HIPEF or thermal treatments except for ascorbic acid. Milk retained more ascorbic acid after a 400 microstreatment at 22.6 kV/cm (93.4%) than after low (63 degrees C-30 min; 49.7% retained) or high (75 degrees C-15s; 86.7% retained) heat pasteurisation treatments. Retention of ascorbic acid fitted a first-order kinetic model for both HIPEF and thermal processes. First-order constant values varied from 1.8 x 10.4 to 1.27 x 10(-3) micros(-1) for the HIPEF treatments (18.3-27.1 kV/cm) and, for thermal processing ranged from 5 x 10(-3) to 8 x 10(-2) min(-1) (50-90 degrees C). No significant differences were found between the results obtained after applying HIPEF treatments at room or moderate temperature. However, results depended on the treatment media. A beneficial effect of natural skim milk components, mainly proteins, was observed on the preservation of ascorbic acid, since skim milk retained more ascorbic acid than SMUF after HIPEF treatments.

  10. Mechanical and Thermal Properties of Pulsed Electric Current Sintered (PECS) Cu-Diamond Compacts

    Science.gov (United States)

    Ritasalo, Riina; Kanerva, Ulla; Ge, Yanling; Hannula, Simo-Pekka

    2014-04-01

    In this work, dispersion strengthening of copper by diamonds is explored. In particular, the influence of 50- and 250-nm diamonds at contents of 3 and 6 vol. pct on the mechanical and thermal properties of pulsed electric current sintered (PECS) Cu composites is studied. The composite powders were prepared by mechanical alloying in argon atmosphere using a high-energy vibratory ball mill. The PECS compacts prepared had high density (>97 pct of T.D.) with quite evenly distributed diamonds. The effectiveness of dispersoids in increasing the microhardness was more pronounced at a smaller particle size and larger volume fraction, explained by Hall-Petch and Orowan strengthening models. The microhardness of Cu with 6 and 3 vol. pct nanodiamonds and pure sm-Cu (submicron-sized Cu) was 1.77, 1.46, and 1.02 GPa, respectively. In annealing experiments at 623 K to 873 K (350 °C to 600 °C), the composites with 6 vol. pct dispersoids retained their hardness better than those with less dispersoids or sm-Cu. The coefficient of thermal expansion was lowered when diamonds were added, being the lowest at about 14 × 10-6 K-1 between 473 K and 573 K (200 °C and 300 °C). Good bonding between the copper and diamond was qualitatively demonstrated by nanoindentation. In conclusion, high-quality Cu-diamond composites can be produced by PECS with improved strength and better thermal stability than for sm-Cu.

  11. Cytoprotective Role of Nrf2 in Electrical Pulse Stimulated C2C12 Myotube.

    Directory of Open Access Journals (Sweden)

    Masaki Horie

    Full Text Available Regular physical exercise is central to a healthy lifestyle. However, exercise-related muscle contraction can induce reactive oxygen species and reactive nitrogen species (ROS/RNS production in skeletal muscle. The nuclear factor-E2-related factor-2 (Nrf2 transcription factor is a cellular sensor for oxidative stress. Regulation of nuclear Nrf2 signaling regulates antioxidant responses and protects organ structure and function. However, the role of Nrf2 in exercise- or contraction-induced ROS/RNS production in skeletal muscle is not clear. In this study, using differentiated C2C12 cells and electrical pulse stimulation (EPS of muscle contraction, we explored whether Nrf2 plays a role in the skeletal muscle response to muscle contraction-induced ROS/RNS. We found that EPS (40 V, 1 Hz, 2 ms stimulated ROS/RNS accumulation and Nrf2 activation. We also showed that expression of NQO1, HO-1 and GCLM increased after EPS-induced muscle contraction and was remarkably suppressed in cells with Nrf2 knockdown. We also found that the antioxidant N-acetylcysteine (NAC significantly attenuated Nrf2 activation after EPS, whereas the nitric oxide synthetase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME did not. Furthermore, Nrf2 knockdown after EPS markedly decreased ROS/RNS redox potential and cell viability and increased expression of the apoptosis marker Annexin V in C2C12 myotubes. These results indicate that Nrf2 activation and expression of Nrf2 regulated-genes protected muscle against the increased ROS caused by EPS-induced muscle contraction. Thus, our findings suggest that Nrf2 may be a key factor for preservation of muscle function during muscle contraction.

  12. Remote detection of radioactive material using high-power pulsed electromagnetic radiation.

    Science.gov (United States)

    Kim, Dongsung; Yu, Dongho; Sawant, Ashwini; Choe, Mun Seok; Lee, Ingeun; Kim, Sung Gug; Choi, EunMi

    2017-05-09

    Remote detection of radioactive materials is impossible when the measurement location is far from the radioactive source such that the leakage of high-energy photons or electrons from the source cannot be measured. Current technologies are less effective in this respect because they only allow the detection at distances to which the high-energy photons or electrons can reach the detector. Here we demonstrate an experimental method for remote detection of radioactive materials by inducing plasma breakdown with the high-power pulsed electromagnetic waves. Measurements of the plasma formation time and its dispersion lead to enhanced detection sensitivity compared to the theoretically predicted one based only on the plasma on and off phenomena. We show that lower power of the incident electromagnetic wave is sufficient for plasma breakdown in atmospheric-pressure air and the elimination of the statistical distribution is possible in the presence of radioactive material.

  13. A cement channel-detection technique using the pulsed-neutron log

    International Nuclear Information System (INIS)

    Myers, G.D.

    1991-01-01

    A channel-detection technique has been developed using boron solutions and pulsed-neutron logging (PNL) tools. This technique relies on the extremely high-neutron-absorption cross section that boron exhibits relative to other common elements, including chlorine. The PNL tool is used to detect movement of a boron solution in a log-inject-log procedure. The technique has identified channels in such difficult applications as logging through two strings of pipe and in highly deviated wellbores. Logging procedures are simple and cement channels can be readily identified. The boron solutions are relatively inexpensive, safe to handle, and nonradioactive. Additional PNL information for reservoir performance evaluation is collected simultaneously during channel-detection logging. This paper describes the theory, development, field application, and limitations of this channel-detection logging technique

  14. Generation of an isolated sub-30 attosecond pulse in a two-color laser field and a static electric field

    International Nuclear Information System (INIS)

    Zhang Gang-Tai; Zhang Mei-Guang; Bai Ting-Ting

    2012-01-01

    We theoretically investigate high-order harmonic generation (HHG) from a helium ion model in a two-color laser field, which is synthesized by a fundamental pulse and its second harmonic pulse. It is shown that a supercontinuum spectrum can be generated in the two-color field. However, the spectral intensity is very low, limiting the application of the generated attosecond (as) pulse. By adding a static electric field to the synthesized two-color field, not only is the ionization yield of electrons contributing to the harmonic emission remarkably increased, but also the quantum paths of the HHG can be significantly modulated. As a result, the extension and enhancement of the supercontinuum spectrum are achieved, producing an intense isolated 26-as pulse with a bandwidth of about 170.5 eV. In particular, we also analyse the influence of the laser parameters on the ultrabroad supercontinuum spectrum and isolated sub-30-as pulse generation. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  15. Effect of Pulsed Electric Fields on the Flavour Profile of Red-Fleshed Sweet Cherries (Prunus avium var. Stella

    Directory of Open Access Journals (Sweden)

    Kristine Ann Gualberto Sotelo

    2015-03-01

    Full Text Available The aim of this research was to study the effect of pulsed electric fields (PEF on the flavour profile of red-fleshed sweet cherries (Prunus avium variety Stella. The cherry samples were treated at a constant pulse frequency of 100 Hz, a constant pulse width of 20 μs, different electric field strengths between 0.3 and 2.5 kV/cm and specific energy ranging from 31 to 55 kJ/kg. Volatile compounds of samples were analysed using an automated headspace solid phase microextraction (HS–SPME method coupled with gas chromatography-mass spectrometry (GC–MS. A total of 33 volatile compounds were identified with benzaldehyde, hexanal, (E-2-hexenal, (Z-2-hexen-1-ol, and benzyl alcohol being the predominant volatiles in different PEF-treated samples. Aldehydes namely butanal, octanal, 2-octenal, and nonanal, and (Z-2-hexen-1-ol increased significantly 24 h after PEF treatment at electric field strengths of more than 1.0 kV/cm. Samples incubated for 24 h after PEF treatment (S3 generated higher concentrations of volatiles than samples immediately after PEF treatments (S2. Quantitative results revealed that more flavour volatiles were released and associated with S3 samples after 24 h storage and S2 samples immediately after PEF both with the highest electric field intensities. Interestingly, this study found that the PEF treatments at the applied electric field strength and energy did not result in releasing/producing undesirable flavour compounds.

  16. Using a forehead reflectance pulse oximeter to detect changes in sympathetic tone.

    Science.gov (United States)

    Wendelken, Suzanne M; McGrath, Susan P; Akay, Metin; Blike, George T

    2004-01-01

    The extreme conditions of combat and multi-casualty rescue often make field triage difficult and put the medic or first responder at risk. In an effort to improve field triage, we have developed an automated remote triage system called ARTEMIS (automated remote triage and emergency management information system) for use in the battlefield or disaster zone. Common to field injuries is a sudden change in arterial pressure resulting from massive blood loss or shock. In effort to stabilize the arterial pressure, the sympathetic system is strongly activated and sympathetic tone is increased. This preliminary research seeks to empirically demonstrate that a forehead reflectance pulse oximeter is a viable sensor for detecting sudden changes in sympathetic tone. We performed the classic supine-standing experiment and collected the raw waveform, the photoplethysmogram (PPG), continuously using a forehead reflectance pulse oximeter. The resulting waveform was processed in Matlab using various spectral analysis techniques (FFT and AR). Our preliminary results show that a relative ratio analysis (low frequency power/high frequency power) for both the raw PPG signal and its derived pulse statistics (height, beat-to-beat interval) is a useful technique for detecting change in sympathetic tone resulting from positional change.

  17. Impacts of pulsed electric field and heat treatment on quality and sensory properties and microbial inactivation of pomegranate juice.

    Science.gov (United States)

    Evrendilek, Gulsun A

    2017-12-01

    Synergistic effects of pulsed electric field+mild heat on quality properties of pomegranate juice were modeled using the best-fit multiple (non-) linear regression models with inactivation kinetics parameters of Escherichia coli O157:H7 and Staphylococcus aureus. No significant difference was detected between the control and the treated samples in terms of pH; °Brix; total antioxidant capacity; total monomeric anthocyanin content; total ascorbic acid concentration; and the sensory properties of flavor, taste, aftertaste, and overall acceptance ( p > 0.05). An exposure of 65.3 J and 40 ℃ caused an increase on conductivity; titratable acidity; L*, a*, and b* values; and a decrease of browning index, total phenolic content, total antioxidant capacity, total monomeric anthocyanin content, total ascorbic acid concentration, and in the sensory properties of color and sourness in pomegranate juice. The goodness-of-fit for the best-fit multiple (non-) linear regression models in descending order belonged to E. coli O157:H7 (92.98%), S. aureus (84.06%), color a* (83.9%), titratable acidity (81.3%), color L* (78.5%), color b* (78.3%), conductivity (74.8%), total phenolic content (74.1%), and total ascorbic acid concentration (64.74%), respectively. D e and z e values for E. coli O157:H7 and S. aureus ranged from 105.64 to 1093.25 and from 79.18 to 1057.73 µs with 27.39 and 30.80 J, consequently.

  18. Revisiting Bragg's X-ray microscope: scatter based optical transient grating detection of pulsed ionising radiation.

    Science.gov (United States)

    Fullagar, Wilfred K; Paganin, David M; Hall, Chris J

    2011-06-01

    Transient optical gratings for detecting ultrafast signals are routine for temporally resolved photochemical investigations. Many processes can contribute to the formation of such gratings; we indicate use of optically scattering centres that can be formed with highly variable latencies in different materials and devices using ionising radiation. Coherent light scattered by these centres can form the short-wavelength-to-optical-wavelength, incoherent-to-coherent basis of a Bragg X-ray microscope, with inherent scope for optical phasing. Depending on the dynamics of the medium chosen, the way is open to both ultrafast pulsed and integrating measurements. For experiments employing brief pulses, we discuss high-dynamic-range short-wavelength diffraction measurements with real-time optical reconstructions. Applications to optical real-time X-ray phase-retrieval are considered. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Development of a homogeneous pulse shape discriminating flow-cell radiation detection system

    International Nuclear Information System (INIS)

    Hastie, K.H.; DeVol, T.A.; Fjeld, R.A.

    1999-01-01

    A homogeneous flow-cell radiation detection system which utilizes coincidence counting and pulse shape discrimination circuitry was assembled and tested with five commercially available liquid scintillation cocktails. Two of the cocktails, Ultima Flo (Packard) and Mono Flow 5 (National Diagnostics) have low viscosities and are intended for flow applications; and three of the cocktails, Optiphase HiSafe 3 (Wallac), Ultima Gold AB (Packard), and Ready Safe (Beckman), have higher viscosities and are intended for static applications. The low viscosity cocktails were modified with 1-methylnaphthalene to increase their capability for alpha/beta pulse shape discrimination. The sample loading and pulse shape discriminator setting were optimized to give the lowest minimum detectable concentration for methylnaphthalenein a 30 s count time. Of the higher viscosity cocktails, Optiphase HiSafe 3 had the lowest minimum detectable activities for alpha and beta radiation, 0.2 and 0.4 Bq/ml for 233 U and 90 Sr/ 90 Y, respectively, for a 30 s count time. The sample loading was 70% and the corresponding alpha/beta spillover was 5.5%. Of the low viscosity cocktails, Mono Flow 5 modified with 2.5% (by volume) 1-methylnaphthalene resulted in the lowest minimum detectable activities for alpha and beta radiation; 0.3 and 0.5 Bq/ml for 233 U and 90 Sr/ 90 Y, respectively, for a 30 s count time. The sample loading was 50%, and the corresponding alpha/beta spillover was 16.6%. HiSafe 3 at a 10% sample loading was used to evaluate the system under simulated flow conditions

  20. 1st World Congress on Electroporation and Pulsed Electric Fields in Biology, Medicine and Food & Environmental Technologies

    CERN Document Server

    Kramar, Peter

    2016-01-01

    This volume presents the proceedings of the 1st World Congress on Electroporation and Pulsed Electric Fields in Biology, Medicine and Food & Environmental Technologies (WC2015). The congress took place in Portorož, Slovenia, during the week of September 6th to 10th, 2015. The scientific part of the Congress covered different aspects of electroporation and related technologies and included the following main topics:   ·         Application of pulsed electric fields technology in food: challenges and opportunities ·         Electrical impedance measurement for assessment of electroporation yield ·         Electrochemistry and electroporation ·         Electroporation meets electrostimulation ·         Electrotechnologies for food and biomass treatment ·         Food and biotechnology applications ·         In vitro electroporation - basic mechanisms ·         Interfacial behaviour of lipid-assemblies, membranes and cells in electric f...

  1. Note: Tesla based pulse generator for electrical breakdown study of liquid dielectrics

    Science.gov (United States)

    Veda Prakash, G.; Kumar, R.; Patel, J.; Saurabh, K.; Shyam, A.

    2013-12-01

    In the process of studying charge holding capability and delay time for breakdown in liquids under nanosecond (ns) time scales, a Tesla based pulse generator has been developed. Pulse generator is a combination of Tesla transformer, pulse forming line, a fast closing switch, and test chamber. Use of Tesla transformer over conventional Marx generators makes the pulse generator very compact, cost effective, and requires less maintenance. The system has been designed and developed to deliver maximum output voltage of 300 kV and rise time of the order of tens of nanoseconds. The paper deals with the system design parameters, breakdown test procedure, and various experimental results. To validate the pulse generator performance, experimental results have been compared with PSPICE simulation software and are in good agreement with simulation results.

  2. Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice. Part I: Impact on overall quality attributes

    NARCIS (Netherlands)

    Timmermans, R.A.H.; Mastwijk, H.C.; Knol, J.J.; Quataert, M.C.J.; Vervoort, L.; Plancken, van der I.; Hendrickx, M.E.; Matser, A.M.

    2011-01-01

    Mild heat pasteurization, high pressure processing (HP) and pulsed electric field (PEF) processing of freshly squeezed orange juice were comparatively evaluated examining their impact on microbial load and quality parameters immediately after processing and during two months of storage. Microbial

  3. Two-dimensional spatial survey of the plasma potential and electric field in a pulsed bipolar magnetron discharge

    International Nuclear Information System (INIS)

    Vetushka, A.; Karkari, S.K.; Bradley, J.W.

    2004-01-01

    Emissive and Langmuir probe techniques have been used to obtain two-dimensional (2D) spatial maps of the plasma potential V p , electric field E, and ion trajectories in a pulsed bipolar magnetron discharge. The magnetron was pulsed at a frequency of 100 kHz, with a 50% duty cycle and operated at an argon pressure of 0.74 Pa. The pulse wave form was characterized by three distinct phases: the 'overshoot', 'reverse', and 'on' phases. In the 'on' phase of the pulse, when the cathode voltage is driven to -670 V, the 2D spatial distribution of V p has a similar form to that in dc magnetron, with significant axial and radial electric fields in the bulk plasma, accelerating ions to the sheath edge above the cathode racetrack region. During the 'overshoot' phase (duration 200 ns), V p is raised to values greater than +330 V, more than 100 V above the cathode potential, with E pointing away from the target. In the 'reverse' phase V p has a value of +45 V at all measured positions, 2 V more positive than the target potential. In this phase there is no electric field present in the plasma. In the bulk of the plasma, the results from Langmuir probe and the emissive probe are in good agreement, however, in one particular region of the plasma outside the radius of the cathode, the emissive probe measurements are consistently more positive (up to 45 V in the 'on' time). This discrepancy is discussed in terms of the different frequency response of the probes and their perturbation of the plasma. A simple circuit model of the plasma-probe system has been proposed to explain our results. A brief discussion of the effect of the changing plasma potential distribution on the operation of the magnetron is given

  4. Structure and dynamics of paramagnetic transients by pulsed EPR and NMR detection of nuclear resonance. [Pulse radiolysis of methanol in D/sub 2/O

    Energy Technology Data Exchange (ETDEWEB)

    Trifunac, A.D.

    1981-01-01

    Structure and dynamics of transient radicals in pulse radiolysis can be studied by time resolved EPR and NMR techniques. EPR study of kinetics and relaxation is illustrated. The NMR detection of nuclear resonance in transient radicals is a new method which allows the study of hyperfine coupling, population dynamics, radical kinetics, and reaction mechanism. 9 figures.

  5. Droplet size characteristics and energy input requirements of emulsions formed using high-intensity-pulsed electric fields

    International Nuclear Information System (INIS)

    Scott, T.C.; Sisson, W.G.

    1987-01-01

    Experimental methods have been developed to measure droplet size characteristics and energy inputs associated with the rupture of aqueous droplets by high-intensity-pulsed electric fields. The combination of in situ microscope optics and high-speed video cameras allows reliable observation of liquid droplets down to 0.5 μm in size. Videotapes of electric-field-created emulsions reveal that average droplet sizes of less than 5 μm are easily obtained in such systems. Analysis of the energy inputs into the fluids indicates that the electric field method requires less than 1% of the energy required from mechanical agitation to create comparable droplet sizes. 11 refs., 3 figs., 2 tabs

  6. Optimization of pulsed electric field pre-treatments to enhance health-promoting glucosinolates in broccoli flowers and stalk.

    Science.gov (United States)

    Aguiló-Aguayo, Ingrid; Suarez, Manuel; Plaza, Lucia; Hossain, Mohammad B; Brunton, Nigel; Lyng, James G; Rai, Dilip K

    2015-07-01

    The effect of pulsed electric field (PEF) treatment variables (electric field strength and treatment time) on the glucosinolate content of broccoli flowers and stalks was evaluated. Samples were subjected to electric field strengths from 1 to 4 kV cm(-1) and treatment times from 50 to 1000 µs at 5 Hz. Data fitted significantly (P broccoli flowers (ranging from 187.1 to 212.5%) and stalks (ranging from 110.6 to 203.0%) respectively. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values, with low average mean deviations (E%) ranging from 0.59 to 8.80%. The use of PEF processing at moderate conditions could be a suitable method to stimulate production of broccoli with high health-promoting glucosinolate content. © 2014 Society of Chemical Industry.

  7. Determination of carbohydrates by high performance anion chromatography-pulsed amperometric detection in mushrooms.

    Science.gov (United States)

    Zhou, Shuai; Tang, Qingjiu; Luo, Xi; Xue, Jun-Jie; Liu, Yanfang; Yang, Yan; Zhang, Jingsong; Feng, Na

    2012-01-01

    A method of detecting carbohydrates (fucose, trehalose, mannitol, arabitol, mannose, glucose, galactose, fructose, and ribose) by high-performance anion chromatography-pulsed amperometric detection (HAPEC-PAD) was established. The conditions are: CarboPac MA1 column, NaOH as the eluent, temperature 30°C, Au working electrode, Ag/AgCl reference electrode, and flow rate 0.4 mL/min. These nine analytes, which yielded high resolution by this method, could be detected in 40 minutes. Mushrooms were tested and good precision, stability, and reproducibility were achieved. This method is suitable for mushroom samples and could support research and development on sugar and sugar alcohol, which contains special effects.

  8. Spatial-time-state fusion algorithm for defect detection through eddy current pulsed thermography

    Science.gov (United States)

    Xiao, Xiang; Gao, Bin; Woo, Wai Lok; Tian, Gui Yun; Xiao, Xiao Ting

    2018-05-01

    Eddy Current Pulsed Thermography (ECPT) has received extensive attention due to its high sensitive of detectability on surface and subsurface cracks. However, it remains as a difficult challenge in unsupervised detection as to identify defects without knowing any prior knowledge. This paper presents a spatial-time-state features fusion algorithm to obtain fully profile of the defects by directional scanning. The proposed method is intended to conduct features extraction by using independent component analysis (ICA) and automatic features selection embedding genetic algorithm. Finally, the optimal feature of each step is fused to obtain defects reconstruction by applying common orthogonal basis extraction (COBE) method. Experiments have been conducted to validate the study and verify the efficacy of the proposed method on blind defect detection.

  9. Sinkhole detection using electrical resistivity tomography in Saudi Arabia

    International Nuclear Information System (INIS)

    Youssef, Ahmed M; Zabramawi, Yasser A; El-Kaliouby, Hesham

    2012-01-01

    Karst phenomena exist in different areas in the Kingdom of Saudi Arabia, causing serious environmental problems that affect urban development and infrastructure (buildings, roads and highways). One of the most important problems are sinkholes, which most of the time consist of unfilled voids. These sinkholes are formed as a result of the chemical leaching of carbonate and evaporite formations by percolating water. Field investigations show that there are many surface expressions of sinkholes in the area; some appear on the ground surface and others are hidden in the subsurface. Geophysical data were collected at the study area using two-dimensional electrical resistivity tomography (ERT) with different electrode spacings to delineate buried sinkholes and associated subsurface cavities. Our findings indicated that the dipole–dipole method using an electrode spacing of 1 m was successful in detecting a known subsurface sinkhole. According to the ERT method the detected sinkhole depth ranges from 2 to 4 m, its height ranges from 2 to 4 m, and its width ranges from 5 to 7 m. Field observation has verified the geophysical data, especially along the profile A-A. Finally, closely spaced ERT profiles were successful in determining the three-dimensional volume of the subsurface sinkhole. (paper)

  10. Pulsed DC Electric Field-Induced Differentiation of Cortical Neural Precursor Cells.

    Directory of Open Access Journals (Sweden)

    Hui-Fang Chang

    Full Text Available We report the differentiation of neural stem and progenitor cells solely induced by direct current (DC pulses stimulation. Neural stem and progenitor cells in the adult mammalian brain are promising candidates for the development of therapeutic neuroregeneration strategies. The differentiation of neural stem and progenitor cells depends on various in vivo environmental factors, such as nerve growth factor and endogenous EF. In this study, we demonstrated that the morphologic and phenotypic changes of mouse neural stem and progenitor cells (mNPCs could be induced solely by exposure to square-wave DC pulses (magnitude 300 mV/mm at frequency of 100-Hz. The DC pulse stimulation was conducted for 48 h, and the morphologic changes of mNPCs were monitored continuously. The length of primary processes and the amount of branching significantly increased after stimulation by DC pulses for 48 h. After DC pulse treatment, the mNPCs differentiated into neurons, astrocytes, and oligodendrocytes simultaneously in stem cell maintenance medium. Our results suggest that simple DC pulse treatment could control the fate of NPCs. With further studies, DC pulses may be applied to manipulate NPC differentiation and may be used for the development of therapeutic strategies that employ NPCs to treat nervous system disorders.

  11. Pulsed DC Electric Field-Induced Differentiation of Cortical Neural Precursor Cells.

    Science.gov (United States)

    Chang, Hui-Fang; Lee, Ying-Shan; Tang, Tang K; Cheng, Ji-Yen

    2016-01-01

    We report the differentiation of neural stem and progenitor cells solely induced by direct current (DC) pulses stimulation. Neural stem and progenitor cells in the adult mammalian brain are promising candidates for the development of therapeutic neuroregeneration strategies. The differentiation of neural stem and progenitor cells depends on various in vivo environmental factors, such as nerve growth factor and endogenous EF. In this study, we demonstrated that the morphologic and phenotypic changes of mouse neural stem and progenitor cells (mNPCs) could be induced solely by exposure to square-wave DC pulses (magnitude 300 mV/mm at frequency of 100-Hz). The DC pulse stimulation was conducted for 48 h, and the morphologic changes of mNPCs were monitored continuously. The length of primary processes and the amount of branching significantly increased after stimulation by DC pulses for 48 h. After DC pulse treatment, the mNPCs differentiated into neurons, astrocytes, and oligodendrocytes simultaneously in stem cell maintenance medium. Our results suggest that simple DC pulse treatment could control the fate of NPCs. With further studies, DC pulses may be applied to manipulate NPC differentiation and may be used for the development of therapeutic strategies that employ NPCs to treat nervous system disorders.

  12. Pulsed magnetic field excitation sensitivity of match-type electric blasting caps

    Science.gov (United States)

    Parson, Jonathan; Dickens, James; Walter, John; Neuber, Andreas A.

    2010-10-01

    This paper presents a study on energy deposition and electromagnetic compatibility of match-type electroexplosive devices (EEDs), which recently have found more usage in pulsed power environments with high electromagnetic interference (EMI) background. The sensitivity of these devices makes them dangerous to intended and unintended radiation produced by devices commonly used in pulsed power environments. Match-type EEDs have been found to be susceptible to such low levels of energy (7-8 mJ) that safe operation of these EEDs is vital when in use near devices that produce high levels of pulsed EMI. The scope of this paper is to provide an investigation that incorporates results of similar studies to provide detonation characteristics of these EEDs. The three topics included in this study are sensitivity testing, modeling of the thermodynamic heat propagation, and electromagnetic compatibility from pulsed electromagnetic radiation. The thermodynamic joule heating of the primary explosive has been modeled by a solution to the 1D heat equation. A simple pulsed generator, Marx generator with an inductive load, was used for the electromagnetic compatibility assessment of the coupled field between the pulse generator and shorted EED. The results of the electromagnetic compatibility assessment relate the resistive, inductive, and capacitive components of the pulse generator to the area of the shorted EED.

  13. The Development of the Electrically Controlled High Power RF Switch and Its Application to Active RF Pulse Compression Systems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jiquan [Stanford Univ., CA (United States)

    2008-12-01

    In the past decades, there has been increasing interest in pulsed high power RF sources for building high-gradient high-energy particle accelerators. Passive RF pulse compression systems have been used in many applications to match the available RF sources to the loads requiring higher RF power but a shorter pulse. Theoretically, an active RF pulse compression system has the advantage of higher efficiency and compactness over the passive system. However, the key component for such a system an element capable of switching hundreds of megawatts of RF power in a short time compared to the compressed pulse width is still an open problem. In this dissertation, we present a switch module composed of an active window based on the bulk effects in semiconductor, a circular waveguide three-port network and a movable short plane, with the capability to adjust the S-parameters before and after switching. The RF properties of the switch module were analyzed. We give the scaling laws of the multiple-element switch systems, which allow the expansion of the system to a higher power level. We present a novel overmoded design for the circular waveguide three-port network and the associated circular-to-rectangular mode-converter. We also detail the design and synthesis process of this novel mode-converter. We demonstrate an electrically controlled ultra-fast high power X-band RF active window built with PIN diodes on high resistivity silicon. The window is capable of handling multi-megawatt RF power and can switch in 2-300ns with a 1000A current driver. A low power active pulse compression experiment was carried out with the switch module and a 375ns resonant delay line, obtaining 8 times compression gain with a compression ratio of 20.

  14. Method for detecting damage in carbon-fibre reinforced plastic-steel structures based on eddy current pulsed thermography

    Science.gov (United States)

    Li, Xuan; Liu, Zhiping; Jiang, Xiaoli; Lodewijks, Gabrol

    2018-01-01

    Eddy current pulsed thermography (ECPT) is well established for non-destructive testing of electrical conductive materials, featuring the advantages of contactless, intuitive detecting and efficient heating. The concept of divergence characterization of the damage rate of carbon fibre-reinforced plastic (CFRP)-steel structures can be extended to ECPT thermal pattern characterization. It was found in this study that the use of ECPT technology on CFRP-steel structures generated a sizeable amount of valuable information for comprehensive material diagnostics. The relationship between divergence and transient thermal patterns can be identified and analysed by deploying mathematical models to analyse the information about fibre texture-like orientations, gaps and undulations in these multi-layered materials. The developed algorithm enabled the removal of information about fibre texture and the extraction of damage features. The model of the CFRP-glue-steel structures with damage was established using COMSOL Multiphysics® software, and quantitative non-destructive damage evaluation from the ECPT image areas was derived. The results of this proposed method illustrate that damaged areas are highly affected by available information about fibre texture. This proposed work can be applied for detection of impact induced damage and quantitative evaluation of CFRP structures.

  15. Milk processed by pulsed electric fields: evaluation of microbial quality, physicochemical characteristics, and selected nutrients at different storage conditions.

    Science.gov (United States)

    Bermúdez-Aguirre, Daniela; Fernández, Sulmer; Esquivel, Heracleo; Dunne, Patrick C; Barbosa-Cánovas, Gustavo V

    2011-01-01

    Pulsed electric fields (PEF) technology was used to pasteurize raw milk under selected treatments. Processing conditions were: temperature 20, 30, and 40 °C, electric field 30.76 to 53.84 kV/cm, and pulse numbers 12, 24, and 30 for skim milk (SM), and 12, 21, and 30 for whole milk (WM) (2 μs pulse width, monopolar). Physicochemical parameters (pH, electrical conductivity, density, color, solids nonfat [SNF]) and composition (protein and fat content) were measured after processing. Shelf life of SM and WM was assessed after processing at 46.15 kV/cm, combined with temperature (20 to 60 °C) and 30 pulses. Mesophilic and psychrophilic loads and pH were evaluated during storage at 4 and 21 °C. Results showed minor variations in physicochemical properties after processing. There was an interesting trend in SM in SNF, which decreased as treatment became stronger; similar behavior was observed for fat and protein, showing a 0.18% and 0.17% decrease, respectively, under the strongest conditions. Protein and fat content decreased in WM samples treated at 40 °C, showing a decrease in protein (0.11%), and an even higher decrease in fat content. During storage, PEF-treated milk samples showed higher stability at 4 °C with minor variations in pH; after 33 d, pH was higher than 6. However samples at 21 °C showed faster spoilage and pH dropped to 4 after 5 d. Growth of mesophilic bacteria was delayed in both milks after PEF processing, showing a 6- and 7-log cycles for SM and WM, respectively, after day 25 (4 °C); however, psychrophilic bacteria grew faster in both cases. Pulsed electric fields (PEF) technology in the pasteurization of liquid food products has shown positive results. Processing times can be reduced considerably, which in turn reduces the loss of nutrients and offers important savings in energy. PEF has been used successfully to pasteurize some liquid foods, but it is still not used commercially in milk pasteurization, although several trials have shown

  16. Pulsed magnetic flux leakage method for hairline crack detection and characterization

    Science.gov (United States)

    Okolo, Chukwunonso K.; Meydan, Turgut

    2018-04-01

    The Magnetic Flux leakage (MFL) method is a well-established branch of electromagnetic Non-Destructive Testing (NDT), extensively used for evaluating defects both on the surface and far-surface of pipeline structures. However the conventional techniques are not capable of estimating their approximate size, location and orientation, hence an additional transducer is required to provide the extra information needed. This research is aimed at solving the inevitable problem of granular bond separation which occurs during manufacturing, leaving pipeline structures with miniature cracks. It reports on a quantitative approach based on the Pulsed Magnetic Flux Leakage (PMFL) method, for the detection and characterization of the signals produced by tangentially oriented rectangular surface and far-surface hairline cracks. This was achieved through visualization and 3D imaging of the leakage field. The investigation compared finite element numerical simulation with experimental data. Experiments were carried out using a 10mm thick low carbon steel plate containing artificial hairline cracks with various depth sizes, and different features were extracted from the transient signal. The influence of sensor lift-off and pulse width variation on the magnetic field distribution which affects the detection capability of various hairline cracks located at different depths in the specimen is explored. The findings show that the proposed technique can be used to classify both surface and far-surface hairline cracks and can form the basis for an enhanced hairline crack detection and characterization for pipeline health monitoring.

  17. Influence of picosecond pulse electric field to invasive ability of cervical cancer

    Directory of Open Access Journals (Sweden)

    Li-mei WU

    2015-10-01

    Full Text Available Objective To investigate the influence of picosecond pulse electric field (psPEF to the invasive ability of cervical cancer. Methods The model of cervical cancer was reproduced in BALB/c nude mice (n=24, and they were randomly divided into four groups (n=6 when the xenografts had grown reaching a diameter of 0.8-1.0cm: control group (psPEF was not given, low field intensity group (50kV/cm, moderate field intensity group (60kV/cm and high field intensity group (70kV/cm. Seven days after the psPEF treatment, the histomorphological changes were observed with HE staining and transmission electron microscopy (TEM, the expressions of vascular endothelial growth factor (VEGF and matrix metalloproteinases-9 (MMP-9 were determined with immunohistochemical (IHC staining, and the changes in protein level of VEGF and MMP-9 were assessed with Western blotting. Results After psPEF treatment, the area of necrosis was found to be increased with an increase in psPEF intensity. With TEM different degrees of apoptosis and necrosis in tumor cells with an increase of psPEF intensity were found. IHC showed that the number of VEGF and MMP-9 positive cells in cancer tissue was decreased with an increase in psPEF intensity. The average optical density (AOD of VEGF and MMP-9 proteins decreased significantly in psPEF treatment groups compared with that in control group, and the AOD values in psPEF treatment groups decreased with an increase in psPEF intensity, and the decrease was statistically significant (P<0.05. Western blotting showed the expressive levels of VEGF and MMP-9 proteins declined gradually with an increase in psPEF intensity, and the difference between groups was statistically significant (P<0.05. Conclusion psPEF may have anti-cervical cancer effects by inhibiting the secretion of VEGF and MMP-9 and reducing the invasive ability of cervical cancer cells. DOI: 10.11855/j.issn.0577-7402.2015.09.03

  18. Quality assessment and shelf life modeling of pulsed electric field pretreated osmodehydrofrozen kiwifruit slices

    Directory of Open Access Journals (Sweden)

    Efimia Dermesonlouoglou

    2018-04-01

    Full Text Available The objective of this workwas to investigate the potential use of pulsed electric field (PEF in combination with osmotic dehydration (OD as a pre-freezing step and to evaluate the effect on quality characteristics and shelf life of frozen kiwifruit. Peeled kiwifruit was subjected to PEF (1.8 kV/cm, sliced and treated in OD-solution [containing glycerol, maltodextrin, trehalose, ascorbic acid, calcium chloride, citric acid, sodium chloride; 1/5 (wfruit/wsolution] for 30 and 60 min at 35 °C. Combined, PEF only and OD only treated samples as well as nontreated and blanched (80 °C, 60 s samples were frozen and stored at constant (-5, -10, -15, -25 °C and dynamic temperature conditions (-18 °C-3 d, -8 °C-2.5 d, -15 °C-3 d. Quality of frozen samples was evaluated by means of drip loss, colour, texture, vitamin C and sensory evaluation (1-9 scale; and shelf life (SL was calculated. Nontreated and blanched samples presented high drip loss and tissue softening (instrumentally measured as Fmax decrease. The tissue integrity was well retained in all osmotically pretreated samples. PEF pretreatment caused increase of fruit whiteness (increase of L value and yellowness (a and/or b value increase; SL calculation was based on colour change. All OD samples had high vitamin content (24.6 mg/100 g fresh material compared to 138-154 mg/100 g osmodehydrated material; PEF led to 93% (of the initial vitamin retention; blanched samples showed the lowest retention (86.9% of the initial (criteria for SL calculation. OD and combined PEF-OD treatment increased the shelf life of frozen kiwifruit (up to 3 times; based on sensorial criteria. The developed kinetic models for colour change, vitamin loss, and sensory quality deterioration were validated at dynamic temperature conditions. PEF pretreated OD (at significantly shorter time, 30 min compared to 60 min kiwifruits retained optimum quality and sensory characteristics. PEF and OD could be used as a preprocessing

  19. Sterilization of liquid foods by pulsed electric fields – an innovative ultra-high temperature process

    Directory of Open Access Journals (Sweden)

    Kai eReineke

    2015-05-01

    Full Text Available The intention of this study was to investigate the inactivation of endospores by a combined thermal and pulsed electric field (PEF treatment. Therefore, self-cultivated spores of Bacillus subtilis and commercial Geobacillus stearothermophilus spores with certified heat resistance were utilized. Spores of both strains were suspended in saline water (5.3 mS cm-1, skim milk (0.3% fat; 5.3 mS cm-1 and fresh prepared carrot juice (7.73 mS cm-1. The combination of moderate preheating (70-90 °C and an insulated PEF-chamber, combined with a holding tube (65 cm and a heat exchanger for cooling, enabled a rapid heat up to 105-140 °C (measured above the PEF chamber within 92.2-368.9 µs. To compare the PEF process with a pure thermal inactivation, each spore suspension was heat treated in thin glass capillaries and D-values from 90 to 130°C and its corresponding z-values were calculated. For a comparison of the inactivation data, F-values for the temperature fields of both processes were calculated by using Comsol Multiphysics combined with a Matlab routine.A preheating of saline water to 70 °C with a flow rate of 5 l h-1, a frequency of 150 Hz and an energy input of 226.5 kJ kg-1, resulted in a measured outlet temperature of 117 °C and a 4.67 log10 inactivation of Bacillus subtilis. The thermal process with identical F-value caused only a 3.71 log10 inactivation. This synergism of moderate preheating and PEF was even more pronounced for Geobacillus stearothermophilus spores in saline water. A preheating to 95 °C and an energy input of 144 kJ kg-1 resulted in an outlet temperature of 126 °C and a 3.28 log10 inactivation, whereas nearly no inactivation (0.2 log10 was achieved during the thermal treatment.Hence, the PEF technology was evaluated as an alternative ultra-high temperature process. However, for an industrial scale application of this process for sterilization, optimization of the treatment chamber design is needed to reduce the occurring

  20. Antimicrobial activity of suspensions and nanoemulsions of citral in combination with heat or pulsed electric fields.

    Science.gov (United States)

    Pagán, E; Berdejo, D; Espina, L; García-Gonzalo, D; Pagán, R

    2018-01-01

    The application of essential oils in form of nanoemulsions has been proposed as a method to improve their solubility in aqueous solutions, and hence their antimicrobial activity. The objective of this study was to evaluate the antimicrobial activity of citral, applied directly or in combined treatments with heat or pulsed electric fields (PEF), as a function of the inoculation procedure assayed: (i) a simple, vigorous shaking method by vortex agitation (suspension of citral; s-citral) or (ii) the previous preparation of nanoemulsions by the emulsion phase inversion (EPI) method (nanoemulsion of citral; n-citral). n-Citral was more effective in either inhibiting or inactivating Escherichia coli O157:H7 Sakai than s-citral. However, when combined with heat, a greater synergistic effect was observed with s-citral rather than with n-citral, either in lab media (pH 7·0 and 4·0) or apple juice. For instance, while almost 5 log 10 cell cycles were inactivated in apple juice after 15 min at 53°C in the presence of 0·1 μl ml -1 of s-citral, the use of n-citral required 30 min. The use of nanoemulsions did not modify the slight synergism observed when citral and mild PEF were combined (150 μs, 30 kV cm -1 ). The exploration of different delivery systems of antimicrobial compounds such as citral in aqueous food products aids in the establishment of successful combined treatments for food preservation. While at room temperature, citral in form of a nanoemulsion shows a higher antimicrobial activity; its combination with heat would imply a partial loss of the outstanding synergistic lethal effect achieved when added in suspension form. Therefore, the most suitable procedure to magnify the synergism between heat and citral when processing juices would merely require an intense homogenization step prior to the combined treatment. © 2017 The Society for Applied Microbiology.