A bio-inspired electrocommunication system for small underwater robots.

PubMed

Wang, Wei; Liu, Jindong; Xie, Guangming; Wen, Li; Zhang, Jianwei

2017-03-29

Weakly electric fishes (Gymnotid and Mormyrid) use an electric field to communicate efficiently (termed electrocommunication) in the turbid waters of confined spaces where other communication modalities fail. Inspired by this biological phenomenon, we design an artificial electrocommunication system for small underwater robots and explore the capabilities of such an underwater robotic communication system. An analytical model for electrocommunication is derived to predict the effect of the key parameters such as electrode distance and emitter current of the system on the communication performance. According to this model, a low-dissipation, and small-sized electrocommunication system is proposed and integrated into a small robotic fish. We characterize the communication performance of the robot in still water, flowing water, water with obstacles and natural water conditions. The results show that underwater robots are able to communicate electrically at a speed of around 1 k baud within about 3 m with a low power consumption (less than 1 W). In addition, we demonstrate that two leader-follower robots successfully achieve motion synchronization through electrocommunication in the three-dimensional underwater space, indicating that this bio-inspired electrocommunication system is a promising setup for the interaction of small underwater robots.

Underwater spark discharge with long transmission line for cleaning horizontal wells

NASA Astrophysics Data System (ADS)

Lee, Kern; Chung, Kyoung-Jae; Hwang, Y. S.; Kim, C. Y.

2017-06-01

A transmission line is discussed for application in an underwater spark-discharge technique in the cleaning of a horizontal well by incorporating a power-transmission model into the simulation. The pulsed-spark-discharge technique has been proposed for clogged-well rehabilitation, because it removes incrustations that are attached to well screens by using strong pressure waves that are generated by the rapid expansion of a spark channel. To apply the pulsed-spark-discharge technique to the cleaning of horizontal wells, the coaxial cable between the pulsed power supply and the spark gap as a load needs to be extended to a few hundred meters. Prior to field application, pulsed-spark-discharge experiments were conducted and the role of the transmission line was examined using an improved simulation model. In the model, a non-linear interaction of the spark channel and the capacitor bank is described by the pulse-forming action of the coaxial cable. Based on the accurate physical properties of the water plasma, such as the equation of state and electrical conductivity within the region of interest, the amount of energy contributed to the development of a shock wave was evaluated. The simulation shows that if the initial conditions of the spark channel are the same, no further reduction in strength of the pressure wave occurs, even if the cable length is increased above 50 m. Hence, the degraded peak pressure that was observed in the experiments using the longer cable is attributed to a change in the initial condition of the spark channel. The parametric study suggests that the low initial charging voltage, the high ambient water pressure, and the long cable length yield the low initial spark-channel density, which results in a reduced peak pressure. The simulation of line charging is presented to discuss the principle of disturbing the pre-breakdown process by an extended cable.

Evaluation of electrical conductivity and equations of state of non-ideal plasma through microsecond timescale underwater electrical wire explosion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheftman, D.; Krasik, Ya. E.

2011-09-15

Experimental and simulation results of underwater electrical Cu, Al, and W wire explosions in the microsecond timescale are presented. It was shown that the electrical conductivity results for Cu and Al agree well with modified Lee-More and quantum molecular dynamic models for temperatures above 10 kK. The equation of state (EOS) values based on SESAME tables for Cu and Al were slightly modified for intermediate temperatures in order to obtain fitting between experimental and simulated exploding wire radial expansion. Also, it was shown that the electrical conductivity results and the EOS evaluation differ significantly from the results obtained in nanosecondmore » timescale experiments. Finally, it was found that underwater electrical W wire explosion is characterized by the appearance of non-uniformities along the z-axis of the wire. This phenomena adds uncertainty to the possibility of applying this type of experiments for evaluation of the electrical conductivity and EOS of W.« less

Separation and collection of coarse aggregate from waste concrete by electric pulsed power

NASA Astrophysics Data System (ADS)

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.

Combined geophysical methods for mapping infiltration pathways at the Aurora Water Aquifer recharge and recovery site

NASA Astrophysics Data System (ADS)

Jasper, Cameron A.

Although aquifer recharge and recovery systems are a sustainable, decentralized, low cost, and low energy approach for the reclamation, treatment, and storage of post- treatment wastewater, they can suffer from poor infiltration rates and the development of a near-surface clogging layer within infiltration ponds. One such aquifer recharge and recovery system, the Aurora Water site in Colorado, U.S.A, functions at about 25% of its predicted capacity to recharge floodplain deposits by flooding infiltration ponds with post-treatment wastewater extracted from river bank aquifers along the South Platte River. The underwater self-potential method was developed to survey self-potential signals at the ground surface in a flooded infiltration pond for mapping infiltration pathways. A method for using heat as a groundwater tracer within the infiltration pond used an array of in situ high-resolution temperature sensing probes. Both relatively positive and negative underwater self-potential anomalies are consistent with observed recovery well pumping rates and specific discharge estimates from temperature data. Results from electrical resistivity tomography and electromagnetics surveys provide consistent electrical conductivity distributions associated with sediment textures. A lab method was developed for resistivity tests of near-surface sediment samples. Forward numerical modeling synthesizes the geophysical information to best match observed self- potential anomalies and provide permeability distributions, which is important for effective aquifer recharge and recovery system design, and optimization strategy development.

A digital underwater video camera system for aquatic research in regulated rivers

USGS Publications Warehouse

Martin, Benjamin M.; Irwin, Elise R.

2010-01-01

We designed a digital underwater video camera system to monitor nesting centrarchid behavior in the Tallapoosa River, Alabama, 20 km below a peaking hydropower dam with a highly variable flow regime. Major components of the system included a digital video recorder, multiple underwater cameras, and specially fabricated substrate stakes. The innovative design of the substrate stakes allowed us to effectively observe nesting redbreast sunfish Lepomis auritus in a highly regulated river. Substrate stakes, which were constructed for the specific substratum complex (i.e., sand, gravel, and cobble) identified at our study site, were able to withstand a discharge level of approximately 300 m3/s and allowed us to simultaneously record 10 active nests before and during water releases from the dam. We believe our technique will be valuable for other researchers that work in regulated rivers to quantify behavior of aquatic fauna in response to a discharge disturbance.

Characteristics of exploding metal wires in water with three discharge types

NASA Astrophysics Data System (ADS)

Han, Ruoyu; Wu, Jiawei; Zhou, Haibin; Ding, Weidong; Qiu, Aici; Clayson, Thomas; Wang, Yanan; Ren, Hang

2017-07-01

This paper presents the characteristics of underwater electrical wire explosion (UEWE) with three discharge types, namely, Type-A, Type-B, and Type-C. Experiments were carried out with copper and tungsten wires (4 cm long and 50-300 μm in diameter) driven by a microsecond time-scale pulsed current source with 500 J stored energy. A time-integrated spectrometer and a photodiode were used to measure the optical emission of UEWE. A Polyvinylidene Fluoride probe was adopted to record the pressure waveforms. Experimental results indicate that from Type-A to Type-C, more energy deposits prior to the voltage peak and the first peak power increases drastically. This variation of energy deposition influences the optical emission and shock wave generation process. Specifically, the light intensity decreases by more than 90% and the peak of continuous spectra moves from ˜400 nm to ˜700 nm. In addition, the peak pressure of the first shock wave increases from ˜2 MPa to more than 7.5 MPa.

Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and Navigation Support

DTIC Science & Technology

2013-09-30

underwater acoustic communication technologies for autonomous distributed underwater networks, through innovative signal processing, coding, and navigation...in real enviroments , an offshore testbed has been developed to conduct field experimetns. The testbed consists of four nodes and has been deployed...Leadership by the Connecticut Technology Council. Dr. Zhaohui Wang joined the faculty of the Department of Electrical and Computer Engineering at

An energy-harvesting power supply for underwater bridge scour monitoring sensors

NASA Astrophysics Data System (ADS)

Wang, Yuli; Li, Yingjie; He, Longzhuang; Shamsi, Pourya; Zheng, Yahong R.

2018-03-01

The natural force of scouring has become one of the most critical risk endangering the endurance of bridges, thus leading to the necessity of deploying underwater monitoring sensors to actively detect potential scour holes under bridges. Due to the difficulty in re-charging batteries for underwater sensors, super capacitors with energy harvesting (EH) means are exploited to prolong the sustainability of underwater sensors. In this paper, an energy harvesting power supply based on a helical turbine is proposed to power underwater monitoring sensors. A small helical turbine is designed to convert water flow energy to electrical energy with favorable environmental robustness. A 3-inch diameter, 2.5-inch length and 3-bladed helical turbine was designed with two types of waterproof coupling with the sensor housing. Both designs were prototyped and tested under different flow conditions and we get valid voltage around 0.91 V which is enough to power monitoring sensor. The alternating current (AC) electrical energy generated by the helical turbine is then rectified and boosted to drive a DC charger for efficiently charging one super capacitor. The charging circuit was designed, prototyped and tested thoroughly with the helical turbine harvester. The results were promising, that the overall power supply can power an underwater sensor node with wireless transceivers for long-term operations

Application of a high-energy-density permanent magnet material in underwater systems

NASA Astrophysics Data System (ADS)

Cho, C. P.; Egan, C.; Krol, W. P.

1996-06-01

This paper addresses the application of high-energy-density permanent magnet (PM) technology to (1) the brushless, axial-field PM motor and (2) the integrated electric motor/pump system for under-water applications. Finite-element analysis and lumped parameter magnetic circuit analysis were used to calculate motor parameters and performance characteristics and to conduct tradeoff studies. Compact, efficient, reliable, and quiet underwater systems are attainable with the development of high-energy-density PM material, power electronic devices, and power integrated-circuit technology.

Ocean outfall plume characterization using an Autonomous Underwater Vehicle.

PubMed

Rogowski, Peter; Terrill, Eric; Otero, Mark; Hazard, Lisa; Middleton, William

2013-01-01

A monitoring mission to map and characterize the Point Loma Ocean Outfall (PLOO) wastewater plume using an Autonomous Underwater Vehicle (AUV) was performed on 3 March 2011. The mobility of an AUV provides a significant advantage in surveying discharge plumes over traditional cast-based methods, and when combined with optical and oceanographic sensors, provides a capability for both detecting plumes and assessing their mixing in the near and far-fields. Unique to this study is the measurement of Colored Dissolved Organic Matter (CDOM) in the discharge plume and its application for quantitative estimates of the plume's dilution. AUV mission planning methodologies for discharge plume sampling, plume characterization using onboard optical sensors, and comparison of observational data to model results are presented. The results suggest that even under variable oceanic conditions, properly planned missions for AUVs equipped with an optical CDOM sensor in addition to traditional oceanographic sensors, can accurately characterize and track ocean outfall plumes at higher resolutions than cast-based techniques.

Peculiarity of convergence of shock wave generated by underwater electrical explosion of ring-shaped wire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shafer, D.; Toker, G. R.; Gurovich, V. Tz.

2013-05-15

Nanosecond timescale underwater electrical wire explosions of ring-shaped Cu wires were investigated using a pulsed generator with a current amplitude up to 50 kA. It was shown that this type of wire explosion results in the generation of a toroidal shock wave (SW). Time- and space-resolved optical diagnostics were used to determine azimuthal uniformity of the shock wave front and its velocity. It was found that the shock wave preserves its circular front shape in the range of radii 50μm

Carbon Nanotube Underwater Acoustic Thermophone

DTIC Science & Technology

2016-09-23

Attorney Docket No. 300009 1 of 8 A CARBON NANOTUBE UNDERWATER ACOUSTIC THERMOPHONE STATEMENT OF GOVERNMENT INTEREST [0001] The...the Invention [0003] The present invention is an acoustically transparent carbon nanotube thermophone. (2) Description of the Prior Art [0004...Traditional acoustic transduction typically begins with the generation of electrical excitation pulsed through an amplifier into an electro- acoustic

A modified resistance equation for modeling underwater spark discharge with salinity and high pressure conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Pengfei; Roy, Subrata, E-mail: roy@ufl.edu

2014-05-07

This work investigates the performance of underwater spark discharge relating to bubble growth and decay under high pressure and with salinity conditions by introducing a modified form of the resistance equation. Here, we study salinity influence on circuit parameters by fitting the experimental data for which gap resistance is much larger in conductive water than in dielectric water. Accordingly, the resistance equation is modified by considering the influence of both plasma and its surrounding liquid. Thermal radiation effect of the bubble is also studied by comparing two different radiation models. Numerical results predict a larger bubble pressure for saline watermore » but a reduced size and a smaller bubble cycle at a greater water depth. Such study may be useful in many saltwater applications, including that for deep sea conditions.« less

STS-37 crewmembers move CETA electrical cart along rail in JSC's WETF pool

NASA Image and Video Library

1989-12-06

STS-37 Atlantis, Orbiter Vehicle (OV) 104, Mission Specialist (MS) Jerry L. Ross generates electrical power using hand pedals to move crew and equipment translation aid (CETA) cart along a rail during underwater session in JSC's Weightless Environment Training Facility (WETF) Bldg 29. Wearing an extravehicular mobility unit (EMU), Ross operates CETA electrical cart as MS Jerome Apt holds onto the back of the cart. The two crewmembers are practicing a extravehicular activity (EVA) spacewalk they will perform in OV-104's payload bay during STS-37. CETA is a type of railroad hand cart planned as a spacewalker's transportation system along the truss of Space Station Freedom (SSF). SCUBA divers monitor astronauts' underwater activity.

Reactive underwater object inspection based on artificial electric sense.

PubMed

Lebastard, Vincent; Boyer, Frédéric; Lanneau, Sylvain

2016-07-26

Weakly electric fish can perform complex cognitive tasks based on extracting information from blurry electric images projected from their immediate environment onto their electro-sensitive skin. In particular they can be trained to recognize the intrinsic properties of objects such as their shape, size and electric nature. They do this by means of novel perceptual strategies that exploit the relations between the physics of a self-generated electric field, their body morphology and the ability to perform specific movement termed probing motor acts (PMAs). In this article we artificially reproduce and combine these PMAs to build an autonomous control strategy that allows an artificial electric sensor to find electrically contrasted objects, and to orbit around them based on a minimum set of measurements and simple reactive feedback control laws of the probe's motion. The approach does not require any simulation models and could be implemented on an autonomous underwater vehicle (AUV) equipped with artificial electric sense. The AUV has only to satisfy certain simple geometric properties, such as bi-laterally (left/right) symmetrical electrodes and possess a reasonably high aspect (length/width) ratio.

Relationship between energy deposition and shock wave phenomenon in an underwater electrical wire explosion

NASA Astrophysics Data System (ADS)

Han, Ruoyu; Zhou, Haibin; Wu, Jiawei; Qiu, Aici; Ding, Weidong; Zhang, Yongmin

2017-09-01

An experimental study of pressure waves generated by an exploding copper wire in a water medium is performed. We examined the effects of energy deposited at different stages on the characteristics of the resulting shock waves. In the experiments, a microsecond time-scale pulsed current source was used to explode a 300-μm-diameter, 4-cm-long copper wire with initial stored energies ranging from 500 to 2700 J. Our experimental results indicated that the peak pressure (4.5-8.1 MPa) and energy (49-287 J) of the shock waves did not follow a simple relationship with any electrical parameters, such as peak voltage or deposited energy. Conversely, the impulse had a quasi-linear relationship with the parameter Π. We also found that the peak pressure was mainly influenced by the energy deposited before separation of the shock wave front and the discharge plasma channel (DPC). The decay time constant of the pressure waveform was affected by the energy injection after the separation. These phenomena clearly demonstrated that the deposited energy influenced the expansion of the DPC and affected the shock wave characteristics.

Converging shock wave focusing and interaction with a target

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nitishinskiy, M.; Efimov, S.; Antonov, O.

2016-04-15

Converging shock waves in liquids can be used efficiently in the research of the extreme state of matter and in various applications. In this paper, the recent results related to the interaction of a shock wave with plasma preliminarily formed in the vicinity of the shock wave convergence are presented. The shock wave is produced by the underwater electrical explosion of a spherical wire array. The plasma is generated prior to the shock wave's arrival by a low-pressure gas discharge inside a quartz capillary placed at the equatorial plane of the array. Analysis of the Stark broadening of H{sub α}more » and H{sub β} spectral lines and line-to-continuum ratio, combined with the ratio of the relative intensities of carbon C III/C II and silicon Si III/Si II lines, were used to determine the plasma density and temperature evolution. It was found that during the first ∼200 ns with respect to the beginning of the plasma compression by the shock wave and when the spectral lines are resolved, the plasma density increases from 2 × 10{sup 17 }cm{sup −3} to 5 × 10{sup 17 }cm{sup −3}, while the temperature remains at the same value of 3–4 eV. Further, following the model of an adiabatically imploding capillary, the plasma density increases >10{sup 19 }cm{sup −3}, leading to the continuum spectra obtained experimentally, and the plasma temperature >30 eV at radii of compression of ≤20 μm. The data obtained indicate that the shock wave generated by the underwater electrical explosion of a spherical wire array retains its uniformity during the main part of its convergence.« less

Ultrasound acoustic wave energy transfer and harvesting

NASA Astrophysics Data System (ADS)

Shahab, Shima; Leadenham, Stephen; Guillot, François; Sabra, Karim; Erturk, Alper

2014-04-01

This paper investigates low-power electricity generation from ultrasound acoustic wave energy transfer combined with piezoelectric energy harvesting for wireless applications ranging from medical implants to naval sensor systems. The focus is placed on an underwater system that consists of a pulsating source for spherical wave generation and a harvester connected to an external resistive load for quantifying the electrical power output. An analytical electro-acoustic model is developed to relate the source strength to the electrical power output of the harvester located at a specific distance from the source. The model couples the energy harvester dynamics (piezoelectric device and electrical load) with the source strength through the acoustic-structure interaction at the harvester-fluid interface. Case studies are given for a detailed understanding of the coupled system dynamics under various conditions. Specifically the relationship between the electrical power output and system parameters, such as the distance of the harvester from the source, dimensions of the harvester, level of source strength, and electrical load resistance are explored. Sensitivity of the electrical power output to the excitation frequency in the neighborhood of the harvester's underwater resonance frequency is also reported.

77 FR 5817 - Ocean Renewable Power Company, Tidal Energy Project, Cobscook Bay, ME

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-06

... ocean floor, used for generating electricity from tidal currents and is now providing the public the... impacts associated with installation of an underwater cable assembly to transfer electricity to a power...

Body Fat Measurement: Weighing the Pros and Cons of Electrical Impedance.

ERIC Educational Resources Information Center

Nash, Heyward L.

1985-01-01

Research technologists have developed electrical impedance units in response to demand for a convenient and reliable method of measuring body fat. Accuracy of impedance measures versus calipers and underwater weighing are discussed. (MT)

Time series dataset of fish assemblages near thermal discharges at nuclear power plants in northern Taiwan.

PubMed

Chen, Hungyen; Chen, Ching-Yi; Shao, Kwang-Tsao

2018-05-08

Long-term time series datasets with consistent sampling methods are rather rare, especially the ones of non-target coastal fishes. Here we described a long-term time series dataset of fish collected by trammel net fish sampling and observed by an underwater diving visual census near the thermal discharges at two nuclear power plants on the northern coast of Taiwan. Both experimental and control stations of these two investigations were monitored four times per year in the surrounding seas at both plants from 2000 to 2017. The underwater visual census mainly monitored reef fish assemblages and trammel net samples monitored pelagic or demersal fishes above the muddy/sandy bottom. In total, 508 samples containing 203,863 individuals from 347 taxa were recorded in both investigations at both plants. These data can be used by ecologists and fishery biologists interested in the elucidation of the temporal patterns of species abundance and composition.

Design of Omni Directional Remotely Operated Vehicle (ROV)

NASA Astrophysics Data System (ADS)

Rahimuddin; Hasan, Hasnawiya; Rivai, Haryanti A.; Iskandar, Yanu; Claudio, P.

2018-02-01

Nowadays, underwater activities are increased with the increase of oil resources finding. The gap between demand and supply of oil and gas cause engineers to find oil and gas resources in deep water. In other side, high risk of working in deep underwater environment can cause a dangerous situation for human. Therefore, many research activities are developing an underwater vehicle to replace the human’s work such as ROV or Remotely Operated Vehicles. The vehicle operated using tether to transport the signals and electric power from the surface vehicle. Arrangements of weight, buoyancy, and the propeller placements are significant aspect in designing the vehicle’s performance. This paper presents design concept of ROV for survey and observation the underwater objects with interaction vectored propellers used for vehicle’s motions.

On the Performance of the Underwater Acoustic Sensor Networks

DTIC Science & Technology

2015-05-01

ABOVE ADDRESS. The University of the District of Columbia Computer Science and Informati Briana Lowe Wellman Washington, DC 20008 -1122 ABSTRACT On the...built. I would like to acknowledge the Electrical and Computer Engineering Department which has been helpful throughout my master degree, especially Dr...transmitted message, and, therefore, take advantage of the BER variation, which depends on the underwater acoustic channel environment. Several computer

Underwater Ship Husbandry Discharges

DTIC Science & Technology

2011-11-01

which entered into force in September of 2008, prohibits the use of harmful organotins such as tributyltin (TBT) in AFCs used on international... tributyltin antifouling paints on the introduction and translocation of marine pests in Australia, Report prepared for Australian Department of Agriculture

Physicochemical modifications and applications of carbon nano-onions for electrochemical energy storage

NASA Astrophysics Data System (ADS)

Borgohain, Rituraj

Carbon nano-onions (CNOs), concentrically multilayered fullerenes, are prepared by several different methods. We are studying the properties of two specific CNOs: A-CNOs and N-CNOs. A-CNOs are synthesized by underwater arc discharge, and N-CNOs are synthesized by high-temperature graphitization of commercial nanodiamond. In this study the synthesis of A-CNOs are optimized by designing an arc discharge aparatus to control the arc plasma. Moreover other synthesis parameters such as arc power, duty cycles, temperature, graphitic and metal impurities are controlled for optimum production of A-CNOs. Also, a very efficient purification method is developed to screen out A-CNOs from carboneseous and metal impurities. In general, A-CNOs are larger than N-CNOs (ca. 30 nm vs. 7 nm diameter). The high surface area, appropriate mesoporosity, high thermal stability and high electrical conductivity of CNOs make them a promising material for various applications. These hydrophobic materials are functionalized with organic groups on their outer layers to study their surface chemistry and to decorate with metal oxide nanoparticles. Both CNOs and CNO nanocomposites are investigated for application in electrochemical capacitors (ECs). The influences of pH, concentration and additives on the performance of the composites are studied. Electrochemical measurements demonstrate high specific capacitance and high cycling stability with high energy and power density of the composite materials in aqueous electrolyte. Key words: Carbon Nano-onions, Arc discharge, Purification, Functionalization, Supercapacitor.

Electrically-Conductive Polyaramid Cable And Fabric

NASA Technical Reports Server (NTRS)

Orban, Ralph F.

1988-01-01

Tows coated with metal provide strength and conductance. Cable suitable for use underwater made of electrically conductive tows of metal-coated polyaramid filaments surrounded by electrically insulating jacket. Conductive tows used to make conductive fabrics. Tension borne by metal-coated filaments, so upon release, entire cable springs back to nearly original length without damage.

Research on key technology of prognostic and health management for autonomous underwater vehicle

NASA Astrophysics Data System (ADS)

Zhou, Zhi

2017-12-01

Autonomous Underwater Vehicles (AUVs) are non-cable and autonomous motional underwater robotics. With a wide range of activities, it can reach thousands of kilometers. Because it has the advantages of wide range, good maneuverability, safety and intellectualization, it becomes an important tool for various underwater tasks. How to improve diagnosis accuracy of the AUVs electrical system faults, and how to repair AUVs by the information are the focus of navy in the world. In turn, ensuring safe and reliable operation of the system has very important significance to improve AUVs sailing performance. To solve these problems, in the paper the prognostic and health management(PHM) technology is researched and used to AUV, and the overall framework and key technology are proposed, such as data acquisition, feature extraction, fault diagnosis, failure prediction and so on.

Crystallization to polycrystalline silicon thin film and simultaneous inactivation of electrical defects by underwater laser annealing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Machida, Emi; Research Fellowships of the Japan Society for the Promotion of Science, Japan Society for the Promotion of Science, 1-8 Chiyoda, Tokyo 102-8472; Horita, Masahiro

2012-12-17

We propose a low-temperature laser annealing method of a underwater laser annealing (WLA) for polycrystalline silicon (poly-Si) films. We performed crystallization to poly-Si films by laser irradiation in flowing deionized-water where KrF excimer laser was used for annealing. We demonstrated that the maximum value of maximum grain size of WLA samples was 1.5 {mu}m, and that of the average grain size was 2.8 times larger than that of conventional laser annealing in air (LA) samples. Moreover, WLA forms poly-Si films which show lower conductivity and larger carrier life time attributed to fewer electrical defects as compared to LA poly-Si films.

Underwater Shockwave Pretreatment Process to Improve the Scent of Extracted Citrus junos Tanaka (Yuzu) Juice

PubMed Central

Touyama, Akiko; Nakada, Shina; Higa, Osamu; Itoh, Shigeru

2017-01-01

Citrus junos Tanaka (yuzu) has a strong characteristic aroma and thus its juice is used in various Japanese foods. Herein, we evaluate the volatile compounds in yuzu juice to investigate whether underwater shockwave pretreatment affects its scent. A shockwave pretreatment at increased discharge and energy of 3.5 kV and 4.9 kJ, respectively, increased the content of aroma-active compounds. Moreover, the underwater shockwave pretreatment afforded an approximate tenfold increase in the scent intensity of yuzu juice cultivated in Rikuzentakata. The proposed treatment method exhibited reliable and good performance for the extraction of volatile and aroma-active compounds from the yuzu fruit. The broad applicability and high reliability of this technique for improving the scent of yuzu fruit juice were demonstrated, confirming its potential for application to a wide range of food extraction processes. PMID:28761874

High-performance, polymer-based direct cellular interfaces for electrical stimulation and recording

NASA Astrophysics Data System (ADS)

Kim, Seong-Min; Kim, Nara; Kim, Youngseok; Baik, Min-Seo; Yoo, Minsu; Kim, Dongyoon; Lee, Won-June; Kang, Dong-Hee; Kim, Sohee; Lee, Kwanghee; Yoon, Myung-Han

2018-04-01

Due to the trade-off between their electrical/electrochemical performance and underwater stability, realizing polymer-based, high-performance direct cellular interfaces for electrical stimulation and recording has been very challenging. Herein, we developed transparent and conductive direct cellular interfaces based on a water-stable, high-performance poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) film via solvent-assisted crystallization. The crystallized PEDOT:PSS on a polyethylene terephthalate (PET) substrate exhibited excellent electrical/electrochemical/optical characteristics, long-term underwater stability without film dissolution/delamination, and good viability for primarily cultured cardiomyocytes and neurons over several weeks. Furthermore, the highly crystallized, nanofibrillar PEDOT:PSS networks enabled dramatically enlarged surface areas and electrochemical activities, which were successfully employed to modulate cardiomyocyte beating via direct electrical stimulation. Finally, the high-performance PEDOT:PSS layer was seamlessly incorporated into transparent microelectrode arrays for efficient, real-time recording of cardiomyocyte action potentials with a high signal fidelity. All these results demonstrate the strong potential of crystallized PEDOT:PSS as a crucial component for a variety of versatile bioelectronic interfaces.

Underwater electrical wire explosion: Shock wave from melting being overtaken by shock wave from vaporization

NASA Astrophysics Data System (ADS)

Li, Liuxia; Qian, Dun; Zou, Xiaobing; Wang, Xinxin

2018-05-01

The shock waves generated by an underwater electrical wire explosion were investigated. A microsecond time-scale pulsed current source was used to trigger the electrical explosion of copper wires with a length of 5 cm and a diameter of 200 μm. The energy-storage capacitor was charged to a relatively low energy so that the energy deposited onto the wire was not large enough to fully vaporize the whole wire. Two shock waves were recorded with a piezoelectric gauge that was located at a position of 100 mm from the exploding wire. The first and weak shock wave was confirmed to be the contribution from wire melting, while the second and stronger shock wave was the contribution from wire vaporization. The phenomenon whereby the first shock wave generated by melting being overtaken by the shock wave due to vaporization was observed.

Experimental verification of the vaporization's contribution to the shock waves generated by underwater electrical wire explosion under micro-second timescale pulsed discharge

NASA Astrophysics Data System (ADS)

Han, Ruoyu; Zhou, Haibin; Wu, Jiawei; Clayson, Thomas; Ren, Hang; Wu, Jian; Zhang, Yongmin; Qiu, Aici

2017-06-01

This paper studies pressure waves generated by exploding a copper wire in a water medium, demonstrating the significant contribution of the vaporization process to the formation of shock waves. A test platform including a pulsed current source, wire load, chamber, and diagnostic system was developed to study the shock wave and optical emission characteristics during the explosion process. In the experiment, a total of 500 J was discharged through a copper wire load 0.2 mm in diameter and 4 cm in length. A water gap was installed adjacent to the load so that the current was diverted away from the load after breakdown occurred across the water gap. This allows the electrical energy injection into the load to be interrupted at different times and at different stages of the wire explosion process. Experimental results indicate that when the load was bypassed before the beginning of the vaporization phase, the measured peak pressure was less than 2.5 MPa. By contrast, the peak pressure increased significantly to over 6.5 MPa when the water gap broke down after the beginning of the vaporization phase. It was also found that when bypassing the load after the voltage peak, similar shock waves were produced to those from a non-bypassed load. However, the total optical emission of these bypassed loads was at least an order of magnitude smaller. These results clearly demonstrate that the vaporization process is vital to the formation of shock waves and the energy deposited after the voltage collapse may only have a limited effect.

[The effectiveness of comprehensive rehabilitation of the patients presenting with coronary heart disease with the application of underwater shower massage and electrical stimulation].

PubMed

Rykov, S V; Lebedeva, O D; L'vova, N V; Tupitsina, Iu Iu

2014-01-01

The underwater shower massage and electrical stimulation were applied to treat 120 patients presenting with coronary heart disease. The estimation of the effectiveness of this treatment with the use of functional diagnostic methods revealed its psychocorrective effect manifested in the form of reduced frequency and duration of painful and painless angina seizures, restricted sympathetic influences on the heart as well as normalized sympathovagal balance, lipid status, antioxidative system, central and peripheral hemodynamics, improved systolic and diastolic function of the myocardium, enhanced tolerability of mental, emotional, and physical workload. The study allowed the predictors of the effectiveness of therapeutic and health-promoting measures to be identified.

Experimental and numerical study of the effects of a wall on the coalescence and collapse of bubble pairs

NASA Astrophysics Data System (ADS)

Han, Rui; Zhang, A.-Man; Li, Shuai; Zong, Zhi

2018-04-01

Two-bubble interaction is the most fundamental problem in multi-bubbles dynamics, which is crucial in many practical applications involving air-gun arrays and underwater explosions. In this paper, we experimentally and numerically investigate coalescence, collapse, and rebound of non-buoyant bubble pairs below a rigid wall. Two oscillating vapor bubbles with similar size are generated simultaneously near a rigid wall in axisymmetric configuration using the underwater electric discharge method, and the physical process is captured by a high-speed camera. Numerical simulations are conducted based on potential flow theory coupled with the boundary integral method. Our numerical results show excellent agreement with the experimental data until the splashing of the jet impact sets in. With different ranges of γbw (the dimensionless distance between the rigid wall and the nearest bubble center), the interaction between the coalesced bubble and the rigid wall is divided into three types, i.e., "weak," "intermediate," and "strong." As γbw decreases, the contact point of the two axial jets migrates toward the wall. In "strong interaction" cases, only an upward jet towards the upper rigid wall forms and a secondary jet with a larger width appears at the base of the first jet. The collapsing coalesced bubble in a toroidal form splits into many smaller bubbles due to the instabilities and presents as bubble clouds during the rebounding phase, which may lead to a weakened pressure wave because the focusing energy associated with the collapsing bubble is disintegrated.

Experimental and numerical study on bubble-sphere interaction near a rigid wall

NASA Astrophysics Data System (ADS)

Li, S.; Zhang, A. M.; Han, R.; Liu, Y. Q.

2017-09-01

This study is concerned with the interaction between a violently oscillating bubble and a movable sphere with comparable size near a rigid wall, which is an essential physical phenomenon in many applications such as cavitation, underwater explosion, ultrasonic cleaning, and biomedical treatment. Experiments are performed in a cubic water tank, and the underwater electric discharge technique (580 V DC) is employed to generate a bubble that is initiated between a rigid wall and a sphere in an axisymmetric configuration. The bubble-sphere interactions are captured using a high-speed camera operating at 52 000 frames/s. A classification of the bubble-sphere interaction is proposed, i.e., "weak," "intermediate," and "strong" interactions, identified with three distinct bubble shapes at the maximum volume moment. In the numerical simulations, the boundary integral method and the auxiliary function method are combined to establish a full coupling model that decouples the mutual dependence between the force and the sphere motion. The main features of bubble dynamics in different experiments are well reproduced by our numerical model. Meanwhile, the pressure and velocity fields are also provided for clarifying the associated mechanisms. The effects of two dimensionless standoff parameters, namely, γs (defined as ds/Rm, where ds is the minimum distance between the initial bubble center and the sphere surface and Rm is the maximum bubble radius) and γw (defined as dw/Rm, where dw is the distance between the initial bubble center and the rigid wall), are also discussed.

Right-Angle Mechanized Electrical Connector

NASA Technical Reports Server (NTRS)

Collins, Clint A.; Blackler, David T.

1996-01-01

Right-angle electrical connector embedded in mechanism accommodates some initial misalignment and aligns itself. Connection and disconnection effected with relatively small forces and torques and simple movements. Actuated by one gloved hand or by robotic manipulator. Useful in underwater, nuclear, hot, cold, or toxic environments in which connections made or broken by heavily clothed technicians or by robots.

Improving the antioxidant functionality of Citrus junos Tanaka (yuzu) fruit juice by underwater shockwave pretreatment.

PubMed

Kuraya, Eisuke; Nakada, Shina; Touyama, Akiko; Itoh, Shigeru

2017-02-01

Citrus junos Tanaka (yuzu) has a strong characteristic aroma, and hence, yuzu juice is used in a number of Japanese foods. We herein evaluated the functional compounds of yuzu juice to investigate whether underwater shockwave pretreatment affects its functionality. Employing the shockwave pretreatment at an increased discharge and energy of 3.5kV and 4.9kJ, respectively, resulted in an increase in the flavanone glycoside content and oxygen radical absorbance capacity (ORAC). The ORAC value of yuzu juice cultivated in Rikuzentakata increased approximately 1.7 times upon underwater shockwave pretreatment. The treatment method proposed herein exhibited reliable and good performance for the extraction of functional and antioxidant chemicals in yuzu fruits, and was comparable with traditional squeezing methods. The high applicability and reliability of this technique for improving the antioxidant functionality of yuzu fruit juice was demonstrated, confirming the potential for application to a wide range of food extraction processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

The use of underwater high-voltage discharges to improve the efficiency of Jatropha curcas L. biodiesel production.

PubMed

Maroušek, Josef; Itoh, Shigeru; Higa, Osamu; Kondo, Yoshikazu; Ueno, Masami; Suwa, Ryuichi; Komiya, Yasuaki; Tominaga, Jun; Kawamitsu, Yoshinobu

2012-01-01

Underwater high-voltage discharges (3.5 kV) resulting in 4.9 kJ shock waves (50-60 MPa) were studied at the laboratory scale as a Jatropha curcas L. seed disintegration method. Grinding and macerating in an excess of methanol (3.5:1) was advantageous because methanol acts both as a liquid carrier for the pressure shock waves and as a solvent that increases the efficiency of oil extraction while remaining usable for esterification. The influence of the number of shock waves and the intensity of methanol maceration on the heat values of the pressed cake are stated in detail. Soxhlet extraction demonstrated that a greater than 94% oil extraction was achieved. The increased disintegration of vacuoles rich in oil was documented by surface area analysis, mineralization kinetics analysis, and electron microscopy. The working volumes were small, and the proportion of energy inadequate compared to the yields released; however, much can be improved by upgrading the process. © 2012 International Union of Biochemistry and Molecular Biology, Inc.

Long-term Behavioral Tracking of Freely Swimming Weakly Electric Fish

PubMed Central

Jun, James J.; Longtin, André; Maler, Leonard

2014-01-01

Long-term behavioral tracking can capture and quantify natural animal behaviors, including those occurring infrequently. Behaviors such as exploration and social interactions can be best studied by observing unrestrained, freely behaving animals. Weakly electric fish (WEF) display readily observable exploratory and social behaviors by emitting electric organ discharge (EOD). Here, we describe three effective techniques to synchronously measure the EOD, body position, and posture of a free-swimming WEF for an extended period of time. First, we describe the construction of an experimental tank inside of an isolation chamber designed to block external sources of sensory stimuli such as light, sound, and vibration. The aquarium was partitioned to accommodate four test specimens, and automated gates remotely control the animals' access to the central arena. Second, we describe a precise and reliable real-time EOD timing measurement method from freely swimming WEF. Signal distortions caused by the animal's body movements are corrected by spatial averaging and temporal processing stages. Third, we describe an underwater near-infrared imaging setup to observe unperturbed nocturnal animal behaviors. Infrared light pulses were used to synchronize the timing between the video and the physiological signal over a long recording duration. Our automated tracking software measures the animal's body position and posture reliably in an aquatic scene. In combination, these techniques enable long term observation of spontaneous behavior of freely swimming weakly electric fish in a reliable and precise manner. We believe our method can be similarly applied to the study of other aquatic animals by relating their physiological signals with exploratory or social behaviors. PMID:24637642

Quasi-isentropic compression using compressed water flow generated by underwater electrical explosion of a wire array

NASA Astrophysics Data System (ADS)

Gurovich, V.; Virozub, A.; Rososhek, A.; Bland, S.; Spielman, R. B.; Krasik, Ya. E.

2018-05-01

A major experimental research area in material equation-of-state today involves the use of off-Hugoniot measurements rather than shock experiments that give only Hugoniot data. There is a wide range of applications using quasi-isentropic compression of matter including the direct measurement of the complete isentrope of materials in a single experiment and minimizing the heating of flyer plates for high-velocity shock measurements. We propose a novel approach to generating quasi-isentropic compression of matter. Using analytical modeling and hydrodynamic simulations, we show that a working fluid composed of compressed water, generated by an underwater electrical explosion of a planar wire array, might be used to efficiently drive the quasi-isentropic compression of a copper target to pressures ˜2 × 1011 Pa without any complex target designs.

Artificial gills for robots: MFC behaviour in water.

PubMed

Ieropoulos, Ioannis; Melhuish, Chris; Greenman, John

2007-09-01

This paper reports on the first stage in developing microbial fuel cells (MFCs) which can operate underwater by utilizing dissolved oxygen. In this context, the cathodic half-cell is likened to an artificial gill. Such an underwater power generator has obvious potential for autonomous underwater robots. The electrical power from these devices increased proportionately with water flow rate, temperature and salinity. The current output at ambient temperature (null condition) was 32 microA and this increased by 200% (approximately 100 microA) as a result of a corresponding temperature increase (DeltaT) of 52 degrees C. Similarly, the effect of increasing the water flow rate resulted in an increase in the MFC output ranging from 135% to 150%. Furthermore, the same positive effect was recorded when artificial seawater was used instead, in which case the increase in the MFC current output was >100% (from 32 to 65 microA). There was a distinct difference in the MFC performance when operated under low turbulent as opposed to high turbulent flow rates. These findings can be advantageous in the design of underwater autonomous robots.

Dielectric Barrier Discharges: Pulsed Breakdown, Electrical Characterization and Chemistry

DTIC Science & Technology

2013-06-01

DIELECTRIC BARRIER DISCHARGES : PULSED BREAKDOWN, ELECTRICAL CHARACTERIZATION AND CHEMISTRY  R. Brandenburg, H. Höft, T. Hoder, A. Pipa, R...for pulsed driven Dielectric Barrier Discharges (DBDs) in particular. Fast electrical, optical and spectroscopic methods enable the study of...2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Dielectric Barrier Discharges : Pulsed Breakdown, Electrical Characterization

The effect of different rutile electrodes on mechanical properties of underwater wet welded AH-36 steel plates

NASA Astrophysics Data System (ADS)

Winarto, Winarto; Purnama, Dewin; Churniawan, Iwan

2018-04-01

Underwater welding is an important role in the rescue of ships and underwater structures, in case of emergency. In this study, the marine steel plates used are AH-36 steel as parent material. This type of steel is included in the High Strength Low Alloy (HSLA). Electrodes used for welding AH-36 steel plates are commonly the E6013 and E 7024 which are the type of based rutile electrodes. Those electrodes are widely available on the market and they would be compared with the original electrode for underwater which is the type of E7014 with the trade name of Broco UW-CS-1. Welding method used is Shielding Metal Arc Welding (SMAW) with the variation of 5 m and 10 m underwater depth and also varied with the electric current of 120A, 140A and 250A. It was found that hardness value of increased in the area of weld metal and HAZ. HAZ also tends to have the highest hardness compared to both of weld metal and base metal. Non destructive test by radiographed test (RT) on welds showed that there are found welding defects in the form of incomplete penetration on all variations of welding parameters, but there is no porosity defect detected. The results of the hardness tests of underwater wet welded steel plates show that the hardness value of both rutile electrodes (E6013 and E 7024) is apparently similar hardness value compared with the existing commercial electrode (E7014 of Broco UW-CS- 1). The tensile test results of underwater wet welded steel plates show that the use of rutile electrode of E6013 gives a better tensile properties than other rutile electrodes.

Guiding of Long-Distance Electric Discharges by Combined Femtosecond and Nanosecond Pulses Emitted by Hybrid KrF Laser System

DTIC Science & Technology

2014-01-30

AFRL-AFOSR-UK-TR-2014-0040 Guiding of long-distance electric discharges by combined femtosecond and nanosecond pulses emitted by...To) 27 September 2010 – 31 December 2013 4. TITLE AND SUBTITLE Guiding of long-distance electric discharges by combined femtosecond and...plasma channels in the atmosphere and laser guiding of high-voltage electric discharges . 15. SUBJECT TERMS EOARD, triggering

Low Pressure Experimental Simulation of Electrical Discharges Above and Inside a Cloud

NASA Technical Reports Server (NTRS)

Jarzembski, Maurice A.; Srivastava, Vandana

1996-01-01

A low pressure laboratory experiment to generate sporadic electrical discharges in either a particulate dielectric or air, representing a competing path of preferred electrical breakdown, was investigated. At high pressures, discharges occurred inside the dielectric particulate; at low pressures, discharges occurred outside the dielectric particulate; at a transition pressure regime, which depends on conductivity of the dielectric particulate, discharges were simultaneously generated in both particulate dielectric and air. Unique use of a particulate dielectric was critical for sporadic discharges at lower pressures which were not identical in character to discharges without the particulate dielectric. Application of these experimental results to the field of atmospheric electricity and simulation of the above-cloud type discharges that have recently been documented, called jets and sprites, are discussed.

Uniform and non-uniform modes of nanosecond-pulsed dielectric barrier discharge in atmospheric air: fast imaging and spectroscopic measurements of electric field

PubMed Central

Liu, Chong; Dobrynin, Danil; Fridman, Alexander

2014-01-01

In this study, we report experimental results on fast ICCD imaging of development of nanosecond-pulsed dielectric barrier discharge (DBD) in atmospheric air and spectroscopic measurements of electric field in the discharge. Uniformity of the discharge images obtained with nanosecond exposure times were analyzed using chi-square test. The results indicate that DBD uniformity strongly depends on applied (global) electric field in the discharge gap, and is a threshold phenomenon. We show that in the case of strong overvoltage on the discharge gap (provided by fast rise times), there is transition from filamentary to uniform DBD mode which correlates to the corresponding decrease of maximum local electric field in the discharge. PMID:25071294

Uniform and non-uniform modes of nanosecond-pulsed dielectric barrier discharge in atmospheric air: fast imaging and spectroscopic measurements of electric field.

PubMed

Liu, Chong; Dobrynin, Danil; Fridman, Alexander

2014-06-25

In this study, we report experimental results on fast ICCD imaging of development of nanosecond-pulsed dielectric barrier discharge (DBD) in atmospheric air and spectroscopic measurements of electric field in the discharge. Uniformity of the discharge images obtained with nanosecond exposure times were analyzed using chi-square test. The results indicate that DBD uniformity strongly depends on applied (global) electric field in the discharge gap, and is a threshold phenomenon. We show that in the case of strong overvoltage on the discharge gap (provided by fast rise times), there is transition from filamentary to uniform DBD mode which correlates to the corresponding decrease of maximum local electric field in the discharge.

Focused tandem shock waves in water and their potential application in cancer treatment

NASA Astrophysics Data System (ADS)

Lukes, P.; Sunka, P.; Hoffer, P.; Stelmashuk, V.; Pouckova, P.; Zadinova, M.; Zeman, J.; Dibdiak, L.; Kolarova, H.; Tomankova, K.; Binder, S.; Benes, J.

2014-01-01

The generator of two focused successive (tandem) shock waves (FTSW) in water produced by underwater multichannel electrical discharges at two composite electrodes, with a time delay between the first and second shock waves of 10 s, was developed. It produces, at the focus, a strong shock wave with a peak positive pressure of up to 80 MPa, followed by a tensile wave with a peak negative pressure of up to MPa, thus generating at the focus a large amount of cavitation. Biological effects of FTSW were demonstrated in vitro on hemolysis of erythrocytes and cell viability of human acute lymphoblastic leukemia cells as well as on tumor growth delay ex vivo and in vivo experiments performed with B16 melanoma, T-lymphoma, and R5-28 sarcoma cell lines. It was demonstrated in vivo that FTSW can enhance antitumor effects of chemotherapeutic drugs, such as cisplatin, most likely due to increased permeability of the membrane of cancer cells induced by FTSW. Synergetic cytotoxicity of FTSW with sonosensitive porphyrin-based drug Photosan on tumor growth was observed, possibly due to the cavitation-induced sonodynamic effect of FTSW.

Bio-Inspired Navigation of Chemical Plumes

DTIC Science & Technology

2006-07-01

Bio-Inspired Navigation of Chemical Plumes Maynard J. Porter III, Captain, USAF Department of Electrical and Computer Engineering Air Force Institute...Li. " Chemical plume tracing via an autonomous underwater vehicle". IEEE Journal of Ocean Engineering , 30(2):428— 442, 2005. [6] G. A. Nevitt...Electrical and Computer Engineering Air Force Institute of Technology Dayton, OH 45433-7765, U.S.A. juan.vasquez@afit.edu May 31, 2006 Abstract - The

A Review of Control Strategy of the Large-scale of Electric Vehicles Charging and Discharging Behavior

NASA Astrophysics Data System (ADS)

Kong, Lingyu; Han, Jiming; Xiong, Wenting; Wang, Hao; Shen, Yaqi; Li, Ying

2017-05-01

Large scale access of electric vehicles will bring huge challenges to the safe operation of the power grid, and it’s important to control the charging and discharging of the electric vehicle. First of all, from the electric quality and network loss, this paper points out the influence on the grid caused by electric vehicle charging behaviour. Besides, control strategy of electric vehicle charging and discharging has carried on the induction and the summary from the direct and indirect control. Direct control strategy means control the electric charging behaviour by controlling its electric vehicle charging and discharging power while the indirect control strategy by means of controlling the price of charging and discharging. Finally, for the convenience of the reader, this paper also proposed a complete idea of the research methods about how to study the control strategy, taking the adaptability and possibility of failure of electric vehicle control strategy into consideration. Finally, suggestions on the key areas for future research are put up.

Miniature whirlwinds produced in the laboratory by high-voltage electrical discharges.

PubMed

Ryan, R T; Vonnegut, B

1970-06-12

Laboratory experiments showed that under certain conditions of vorticity the electrical heatinig produced by a high-voltage discharge at atmospheric pressure can cause the formation of a miniature tornado-like vortex. Once it forms, this vortex stabilizes the electrical discharge along its axis and changes its character from that of a spark to high-pressure variety of a glow discharge. Electrical and dynamic parameters were measured. By relating observations and measurements made in these experiments to previous work and to analogous situations in nature, it is concluded that the heating produced by electrical discharges in a large storm may play a significant role in forming and maintaining natural tornadoes.

An experimental system for symmetric capacitive rf discharge studies

NASA Astrophysics Data System (ADS)

Godyak, V. A.; Piejak, R. B.; Alexandrovich, B. M.

1990-09-01

An experimental system has been designed and built to comprehensively study the electrical and plasma characteristics in symmetric capacitively coupled rf discharges at low gas pressures. Descriptions of the system concept, the discharge chamber, the vacuum-gas control system, and the rf matching and electrical measurement system are presented together with some results of electrical measurements carried out in an argon discharge at 13.56 MHz. The system has been specifically designed to facilitate external discharge parameter measurements and probe measurements and to be compatible with a wide variety of other diagnostics. External electrical measurements and probe measurements within the discharge show that it is an ideal vehicle to study low-pressure rf discharge physics. Measurements from this system should be comparable to one-dimensional rf symmetric capacitive discharge theories and may help to verify them. Although only a few results are given here, the system has been operated reliably over a wide range of gas pressures and should give reproducible and accurate results for discharge electrical characteristics and plasma parameters over a wide range of driving frequency and gas components.

2-dimensional simulations of electrically asymmetric capacitively coupled RF-discharges

NASA Astrophysics Data System (ADS)

Mohr, Sebastian; Schulze, Julian; Schuengel, Edmund; Czarnetzki, Uwe

2011-10-01

Capactively coupled RF-discharges are widely used for surface treatment like the deposition of thin films. For industrial applications, the independent control of the ion flux to and the mean energy of the electrons impinging on the surfaces is desired. Experiments and 1D3v-PIC/MCC-simulations have shown that this independent control is possible by applying a fundamental frequency and its second harmonic to the powered electrode. This way, even in geometrically symmetric discharges, as they are often used in industrial reactors, a discharge asymmetry can be induced electrically, hence the name Electrical Asymmetry Effect (EAE). We performed 2D-simulations of electrically asymmetric discharges using HPEM by the group of Mark Kushner, a simulation tool suitable for simulating industrial reactors. First results are presented and compared to previously obtained experimental and simulation data. The comparison shows that for the first time, we succeeded in simulating electrically asymmetric discharges with a 2-dimensional simulation. Capactively coupled RF-discharges are widely used for surface treatment like the deposition of thin films. For industrial applications, the independent control of the ion flux to and the mean energy of the electrons impinging on the surfaces is desired. Experiments and 1D3v-PIC/MCC-simulations have shown that this independent control is possible by applying a fundamental frequency and its second harmonic to the powered electrode. This way, even in geometrically symmetric discharges, as they are often used in industrial reactors, a discharge asymmetry can be induced electrically, hence the name Electrical Asymmetry Effect (EAE). We performed 2D-simulations of electrically asymmetric discharges using HPEM by the group of Mark Kushner, a simulation tool suitable for simulating industrial reactors. First results are presented and compared to previously obtained experimental and simulation data. The comparison shows that for the first time, we succeeded in simulating electrically asymmetric discharges with a 2-dimensional simulation. Funding: German Ministry for the Environment (0325210B).

X-ray Sensitive Material

DTIC Science & Technology

2015-12-01

The research resulted in a composite material that holds a quasi-permanent electric charge and rapidly discharges the electric charge upon X-ray...quasi-permanent electric charge and rapidly discharge the electric charge upon X-ray exposure. The composite material combined the properties of an...9 7. Schematic of Circuit for Recording Sample’s Capacitor Discharge ............... 12 8. Schematic of Circuit for

Using an autonomous Wave Glider to detect seawater anomalies related to submarine groundwater discharge - engineering challenge

NASA Astrophysics Data System (ADS)

Leibold, P.; Brueckmann, W.; Schmidt, M.; Balushi, H. A.; Abri, O. A.

2017-12-01

Coastal aquifer systems are amongst the most precious and vulnerable water resources worldwide. While differing in lateral and vertical extent they commonly show a complex interaction with the marine realm. Excessive groundwater extraction can cause saltwater intrusion from the sea into the aquifers, having a strongly negative impact on the groundwater quality. While the reverse pathway, the discharge of groundwater into the sea is well understood in principle, it's mechanisms and quantities not well constrained. We will present a project that combines onshore monitoring and modeling of groundwater in the coastal plain of Salalah, Oman with an offshore autonomous robotic monitoring system, the Liquid Robotics Wave Glider. Eventually, fluxes detected by the Wave Glider system and the onshore monitoring of groundwater will be combined into a 3-D flow model of the coastal and deeper aquifers. The main tool for offshore SGD investigation project is a Wave Glider, an autonomous vehicle based on a new propulsion technology. The Wave Glider is a low-cost satellite-connected marine craft, consisting of a combination of a sea-surface and an underwater component which is propelled by the conversion of ocean wave energy into forward thrust. While the wave energy propulsion system is purely mechanical, electrical energy for onboard computers, communication and sensors is provided by photovoltaic cells. For the project the SGD Wave Glider is being equipped with dedicated sensors to measure temperature, conductivity, Radon isotope (222Rn, 220Rn) activity concentration as well as other tracers of groundwater discharge. Dedicated software using this data input will eventually allow the Wave Glider to autonomously collect information and actively adapt its search pattern to hunt for spatial and temporal anomalies. Our presentation will focus on the engineering and operational challenges ofdetecting submarine groundwater discharges with the Wave Glider system in the Bay of Salalah, Oman and solutions to overcome them.

Performance characteristics of an electric vehicle lead-acid battery pack at elevated temperatures

NASA Technical Reports Server (NTRS)

Chapman, P.

1982-01-01

Discharge testing data electric car battery pack over initial electrolyte temperature variations between 27 and 55 C are presented. The tests were conducted under laboratory conditions and then compared to detailed electric vehicle simulation models. Battery discharge capacity increased with temperature for constant current discharges, and battery energy capacity increased with temperature for constant power discharges. Dynamometer tests of the electric test vehicle showed an increase in range of 25% for the higher electrolyte temperature.

Exploiting Electric and Magnetic Fields for Underwater Characterization

DTIC Science & Technology

2011-03-01

geophysical surveys are primarily limited to passive magnetic systems towed from a surface vessel. These systems utilize fluxgate , Overhauser, or atomic... magnetometer sensors, often deployed in arrays towed from the stern of small to moderate-size vessels. Active source electromagnetic methods have been

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

NASA Astrophysics Data System (ADS)

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.

Signal Analysis and Waveform Reconstruction of Shock Waves Generated by Underwater Electrical Wire Explosions with Piezoelectric Pressure Probes.

PubMed

Zhou, Haibin; Zhang, Yongmin; Han, Ruoyu; Jing, Yan; Wu, Jiawei; Liu, Qiaojue; Ding, Weidong; Qiu, Aici

2016-04-22

Underwater shock waves (SWs) generated by underwater electrical wire explosions (UEWEs) have been widely studied and applied. Precise measurement of this kind of SWs is important, but very difficult to accomplish due to their high peak pressure, steep rising edge and very short pulse width (on the order of tens of μs). This paper aims to analyze the signals obtained by two kinds of commercial piezoelectric pressure probes, and reconstruct the correct pressure waveform from the distorted one measured by the pressure probes. It is found that both PCB138 and Müller-plate probes can be used to measure the relative SW pressure value because of their good uniformities and linearities, but none of them can obtain precise SW waveforms. In order to approach to the real SW signal better, we propose a new multi-exponential pressure waveform model, which has considered the faster pressure decay at the early stage and the slower pressure decay in longer times. Based on this model and the energy conservation law, the pressure waveform obtained by the PCB138 probe has been reconstructed, and the reconstruction accuracy has been verified by the signals obtained by the Müller-plate probe. Reconstruction results show that the measured SW peak pressures are smaller than the real signal. The waveform reconstruction method is both reasonable and reliable.

Signal Analysis and Waveform Reconstruction of Shock Waves Generated by Underwater Electrical Wire Explosions with Piezoelectric Pressure Probes

PubMed Central

Zhou, Haibin; Zhang, Yongmin; Han, Ruoyu; Jing, Yan; Wu, Jiawei; Liu, Qiaojue; Ding, Weidong; Qiu, Aici

2016-01-01

Underwater shock waves (SWs) generated by underwater electrical wire explosions (UEWEs) have been widely studied and applied. Precise measurement of this kind of SWs is important, but very difficult to accomplish due to their high peak pressure, steep rising edge and very short pulse width (on the order of tens of μs). This paper aims to analyze the signals obtained by two kinds of commercial piezoelectric pressure probes, and reconstruct the correct pressure waveform from the distorted one measured by the pressure probes. It is found that both PCB138 and Müller-plate probes can be used to measure the relative SW pressure value because of their good uniformities and linearities, but none of them can obtain precise SW waveforms. In order to approach to the real SW signal better, we propose a new multi-exponential pressure waveform model, which has considered the faster pressure decay at the early stage and the slower pressure decay in longer times. Based on this model and the energy conservation law, the pressure waveform obtained by the PCB138 probe has been reconstructed, and the reconstruction accuracy has been verified by the signals obtained by the Müller-plate probe. Reconstruction results show that the measured SW peak pressures are smaller than the real signal. The waveform reconstruction method is both reasonable and reliable. PMID:27110789

A study of the glow discharge plasma jet of the novel Hamburger-electrode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wenzheng, E-mail: wzhliu@bjtu.edu.cn; Ma, Chuanlong, E-mail: 15121452@bjtu.edu.cn; Yang, Xiao

2016-08-15

To generate atmospheric pressure glow discharge plasma jets (APGDPJs), a novel Hamburger-electrode was proposed. Through the study on electric field distributions, flow field distributions, and characteristics of the discharge and jet, we found that adopting the mode of dielectric barrier discharge with non-uniform thickness of dielectric, it was easy to form the strong electric field areas which were conducive to generate discharge and electric field distributions with large electric field intensity in the narrow gap and weak electric field intensity in the wide gap that were not inclined to form a filament discharge. Using the structure of evenly distributed innermore » electrodes, it was easy to weaken the pressure of strong electric field areas and form flow field distributions which is beneficial for taking out the high density charged particles and generating APGDPJs. Stable APGDPJs in nitrogen with 3.5 mm in diameter and 9 mm in length were formed by using the novel Hamburger-electrode.« less

CSSC Fish Barrier Simulated Rescuer Touch Point Results, Operating Guidance, and Recommendations for Rescuer Safety

DTIC Science & Technology

2011-09-01

Testing Input electrodes consisting of 1/2” diameter, 6” long copper rods were wired to separate conductors of a shielded, commercially available...underwater-rated electrical cable (three-conductor, shielded, shipboard cable (TSS-2), 18 American Wire Gauge (AWG) stranded copper ). Electrode pairs...sandpaper prior to use to ensure the best electrical continuity between the water and electrode by removing any copper oxide. This electrode

Effect of Nozzle Geometry on Characteristics of Submerged Gas Jet and Bubble Noise.

PubMed

Bie, Hai-Yan; Ye, Jian-Jun; Hao, Zong-Rui

2016-10-01

Submerged exhaust noise is one of the main noise sources of underwater vehicles. The nozzle features of pipe discharging systems have a great influence on exhaust noise, especially on the noise produced by gas-liquid two-phase flow outside the nozzle. To study the influence of nozzle geometry on underwater jet noises, a theoretical study was performed on the critical weber number at which the jet flow field morphology changes. The underwater jet noise experiments of different nozzles under various working conditions were carried out. The experimental results implied that the critical weber number at which the jet flow transformed from bubbling regime to jetting regime was basically identical with the theoretical analysis. In the condition of jetting regime, the generated cavity of elliptical and triangular nozzles was smaller than that of the circular nozzle, and the middle- and high-frequency bands increased nonlinearly. The radiated noise decreased with the decrease in nozzle diameter. Combined with theoretical analysis and experimental research, three different submerged exhaust noise reduction devices were designed, and the validation tests proved that the noise reduction device with folds and diversion cone was the most effective. © 2015 Society for Laboratory Automation and Screening.

Modular AUV System with Integrated Real-Time Water Quality Analysis.

PubMed

Eichhorn, Mike; Ament, Christoph; Jacobi, Marco; Pfuetzenreuter, Torsten; Karimanzira, Divas; Bley, Kornelia; Boer, Michael; Wehde, Henning

2018-06-05

This paper describes the concept, the technical implementation and the practical application of a miniaturized sensor system integrated into an autonomous underwater vehicle (AUV) for real-time acquisition of water quality parameters. The main application field of the presented system is the analysis of the discharge of nitrates into Norwegian fjords near aqua farms. The presented system was developed within the research project SALMON (Sea Water Quality Monitoring and Management) over a three-year period. The development of the sensor system for water quality parameters represented a significant challenge for the research group, as it was to be integrated in the payload unit of the autonomous underwater vehicle in compliance with the underwater environmental conditions. The German company -4H- JENA engineering GmbH (4HJE), with experience in optical in situ-detection of nutrients, designed and built the measurement system. As a carrier platform, the remotely operated vehicle (ROV) "CWolf" from Fraunhofer-Institut für Optronik, Systemtechnik und Bildauswertung - Institutsteil Angewandte Systemtechnik (IOSB-AST) modified to an AUV was deployed. The concept presented illustrates how the measurement system can be integrated easily into the vehicle with a minimum of hard- and software technical interfaces.

Spectroscopy of a plasma formed in the vicinity of implosion of the shock wave generated by underwater electrical explosion of spherical wire array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antonov, O.; Efimov, S.; Gurovich, V. Tz.

The results of visible spectroscopy of the plasma formed inside a copper capillary placed at the equatorial plane of an underwater electrically exploded spherical wire array (30 mm in diameter; 40 wires, each of 100 μm in diameter) are reported. In the experiments, a pulsed power generator with current amplitude of ∼300 kA and rise time of ∼1.1 μs was used to produce wire array explosion accompanied by the formation of a converging strong shock wave. The data obtained support the assumption of uniformity of the shock wave along the main path of its convergence. The spectroscopic measurements show that this rather simple methodmore » of formation of a converging strong shock wave can be used successfully for studying the shock wave's interaction with matter and the evaporation processes of atoms from a target.« less

Electrical discharges in the atmosphere of Venus

NASA Technical Reports Server (NTRS)

Ksanfomaliti, L. V.; Vasilchikov, N. M.; Ganpantserova, O. F.; Petrova, Y. V.; Suvorov, A. P.; Filippov, G. F.; Yablonskaya, O. V.; Yabrova, L. V.

1979-01-01

Data received from Venera 11 and 12 experiments involving the electrical activity of the atmosphere of Venus show that the electrical discharges occur in the cloud layer. Their energy is roughly the same as in terrestrial lightning, but with a pulse repetition frequency of the discharges which is much greater.

Morphological Processing of Ultraviolet Emissions of Electrical Corona Discharge for Analysis and Diagnostic Use

NASA Technical Reports Server (NTRS)

Schubert, Matthew R.; Moore, Andrew J.

2015-01-01

Electron cascades from electrical discharge produce secondary emissions from atmospheric plasma in the ultraviolet band. For a single point of discharge, these emissions exhibit a stereotypical discharge morphology, with latent information about the discharge location. Morphological processing can uncover the location and therefore can have diagnostic utility.

Morphological processing of ultraviolet emissions of electrical corona discharge for analysis and diagnostic use.

PubMed

Schubert, Matthew; Moore, Andrew J

2016-03-01

Electron cascades from electrical discharge produce secondary emissions from atmospheric plasma in the ultraviolet band. For a single point of discharge, these emissions exhibit a stereotypical discharge morphology, with latent information about the discharge location. Morphological processing can uncover the location and therefore have diagnostic utility.

How to increase the efficiency of the electrical discharge method for destruction of nonconductive solid materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voitenko, N. V., E-mail: tevn@hvd.tpu.ru; Yudin, A. S.; Kuznetsova, N. S.

The paper deals with the relevance of using electrical discharge technology for construction works in the city. The technical capabilities of the installation for the multi-borehole electro-discharge splitting off and destruction of rocks and concrete are described. The ways to increase the efficiency of the electrical discharge method for the destruction of solids are proposed. In order to augment the discharge circuit energy, the energy storage is separated into two individual capacitor batteries. The throttle with the inductance of 28.6 μH is installed in one of the batteries, which increases the duration of the channel energy release to 400 μsmore » and the efficiency of electrical discharge splitting off of concrete.« less

Directly measuring melt at a vertical face tidewater glacier: is it possible?

NASA Astrophysics Data System (ADS)

Sutherland, D.; Amundson, J. M.; Duncan, D.; Jackson, R. H.; Kienholz, C.; Motyka, R. J.; Nash, J. D.

2017-12-01

Direct observations of melt on the underwater portion of tidewater glaciers have proved elusive, mostly due to the inherent dangers of making measurements next to a calving ice front. Additionally, the melting process itself is often masked by large ice speeds, variable calving across the glacier front, and enhanced melting due to rising subglacial discharge plumes. Here, we use repeat multibeam sonar images of LeConte Glacier to assess the possibility of measuring terminus melt in situ. LeConte Glacier is a fast-moving tidewater system in southeast Alaska with ice speeds of 25 m d-1 and previously estimated submarine melting that accounts for 50% of ice loss at the front. In August 2016, May 2017, and September 2017, we conducted intensive fieldwork at the 1.5 km long, 250 m deep glacier front, collecting dozens of repeat multibeam images of the underwater terminus. Combined with coincident time-lapse photography and surface radar measurements, we attempt to disentangle the ambient melt at the glacier face from ice motion and calving. We use a suite of oceanographic observations of the emerging subglacial discharge plume to separate portions of the glacier front that show evidence of enhanced melting versus portions outside of the affected plume areas. We find a complex, time-varying geometry, with regions of undercutting, overcutting, and large discharge channels. Measurements like these are critical to i) improving numerical model parameterizations of coupled glacier-ocean interactions and ii) developing a process-based understanding of how the literal ice-ocean boundary evolves in time and space.

Hydrogel microphones for stealthy underwater listening

PubMed Central

Gao, Yang; Song, Jingfeng; Li, Shumin; Elowsky, Christian; Zhou, You; Ducharme, Stephen; Chen, Yong Mei; Zhou, Qin; Tan, Li

2016-01-01

Exploring the abundant resources in the ocean requires underwater acoustic detectors with a high-sensitivity reception of low-frequency sound from greater distances and zero reflections. Here we address both challenges by integrating an easily deformable network of metal nanoparticles in a hydrogel matrix for use as a cavity-free microphone. Since metal nanoparticles can be densely implanted as inclusions, and can even be arranged in coherent arrays, this microphone can detect static loads and air breezes from different angles, as well as underwater acoustic signals from 20 Hz to 3 kHz at amplitudes as low as 4 Pa. Unlike dielectric capacitors or cavity-based microphones that respond to stimuli by deforming the device in thickness directions, this hydrogel device responds with a transient modulation of electric double layers, resulting in an extraordinary sensitivity (217 nF kPa−1 or 24 μC N−1 at a bias of 1.0 V) without using any signal amplification tools. PMID:27554792

Dynamic characteristics of electric discharge in liquid under ultrasonic cavitation

NASA Astrophysics Data System (ADS)

Bulychev, N. A.; Kazaryan, M. A.; Averyushkin, A. S.; Kirichenko, M. N.; Zakharyan, Robert; Chernov, A. A.

2018-04-01

The characteristics of electrical discharges in liquid media under the influence of intense ultrasonic vibrations are investigated and the difference in dynamic characteristics of discharges before cavitation and after cavitation begins. The experiments carried out during this work made it possible to establish that in a liquid in an intense ultrasonic field above the cavitation threshold there exists a special form of an electric discharge characterized by volumetric luminescence in the entire space between the electrodes and the current-voltage characteristic inherent in an anomalous glow discharge in a gas.

Dicarboxylic acids from electric discharge

NASA Technical Reports Server (NTRS)

Zeitman, B.; Chang, S.; Lawless, J. G.

1974-01-01

An investigation was conducted concerning the possible synthesis of a suite of dicarboxylic acids similar to that found in the Murchison meteorite. The investigation included the conduction of a chemical evolution experiment which simulated electric discharge through the primitive atmosphere of the earth. The suite of dicarboxylic acids obtained in the electric discharge experiment is similar to that of the Murchison meteorite, except for the fact that 2-chlorosuccinic acid is present in the spark discharge.

Experimental study and simulation of space charge stimulated discharge

NASA Astrophysics Data System (ADS)

Noskov, M. D.; Malinovski, A. S.; Cooke, C. M.; Wright, K. A.; Schwab, A. J.

2002-11-01

The electrical discharge of volume distributed space charge in poly(methylmethacrylate) (PMMA) has been investigated both experimentally and by computer simulation. The experimental space charge was implanted in dielectric samples by exposure to a monoenergetic electron beam of 3 MeV. Electrical breakdown through the implanted space charge region within the sample was initiated by a local electric field enhancement applied to the sample surface. A stochastic-deterministic dynamic model for electrical discharge was developed and used in a computer simulation of these breakdowns. The model employs stochastic rules to describe the physical growth of the discharge channels, and deterministic laws to describe the electric field, the charge, and energy dynamics within the discharge channels and the dielectric. Simulated spatial-temporal and current characteristics of the expanding discharge structure during physical growth are quantitatively compared with the experimental data to confirm the discharge model. It was found that a single fixed set of physically based dielectric parameter values was adequate to simulate the complete family of experimental space charge discharges in PMMA. It is proposed that such a set of parameters also provides a useful means to quantify the breakdown properties of other dielectrics.

Laser-assisted guiding of electric discharges around objects

PubMed Central

Clerici, Matteo; Hu, Yi; Lassonde, Philippe; Milián, Carles; Couairon, Arnaud; Christodoulides, Demetrios N.; Chen, Zhigang; Razzari, Luca; Vidal, François; Légaré, François; Faccio, Daniele; Morandotti, Roberto

2015-01-01

Electric breakdown in air occurs for electric fields exceeding 34 kV/cm and results in a large current surge that propagates along unpredictable trajectories. Guiding such currents across specific paths in a controllable manner could allow protection against lightning strikes and high-voltage capacitor discharges. Such capabilities can be used for delivering charge to specific targets, for electronic jamming, or for applications associated with electric welding and machining. We show that judiciously shaped laser radiation can be effectively used to manipulate the discharge along a complex path and to produce electric discharges that unfold along a predefined trajectory. Remarkably, such laser-induced arcing can even circumvent an object that completely occludes the line of sight. PMID:26601188

Purification of inkjet ink from water using liquid phase, electric discharge polymerization and cellulosic membrane filtration.

PubMed

Jordan, Alexander T; Hsieh, Jeffery S; Lee, Daniel T

2013-01-01

A method to separate inkjet ink from water was developed using a liquid phase, electric discharge process. The liquid phase, electric discharge process with filtration or sedimentation was shown to remove 97% of inkjet ink from solutions containing between 0.1-0.8 g/L and was consistent over a range of treatment conditions. Additionally, particle size analysis of treated allyl alcohol and treated propanol confirmed the electric discharge treatment has a polymerization mechanism, and small molecule analysis of treated methanol using gas chromatography and mass spectroscopy confirmed the mechanism was free radical initiated polymerization.

Effects of shock waves, ultraviolet light, and electric fields from pulsed discharges in water on inactivation of Escherichia coli.

PubMed

Sun, Bing; Xin, Yanbin; Zhu, Xiaomei; Gao, Zhiying; Yan, Zhiyu; Ohshima, Takayuki

2018-04-01

In this work, the bacterial inactivation effects of shock waves, ultraviolet (UV) light, and electric field produced by high-voltage pulsed discharge in liquid with needle-plate configurations were studied. The contributions of each effect on the bacterial killing ratio in the discharge process were obtained individually by modifying reactor type and usage of glass, quartz, and black balloons. The results showed that the location from the discharge center axis significantly influenced the effects of shock waves and electric fields, although the effect of UV light was not affected by the location in the reactor. The effects of shock waves and electric fields were improved by decreasing the distance from the discharge center axis. Under this experimental condition, the effects of shock waves, UV light, and electric fields produced by discharges on bacterial inactivation were approximately 36.1%, 30.8%, 12.7%, respectively. Other contributions seemed to be due to activated species. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrical discharge heating of chondrules in the solar nebula

NASA Technical Reports Server (NTRS)

Love, Stanley G.; Keil, Klaus; Scott, Edward R. D.

1995-01-01

We present a rudimentary theoretical assessment of electrical discharge heating as a candidate mechanism for the formation of chondrules in the solar nebula. The discharge model combines estimates of the properties of the nebula, a mechanism for terrestrial thunderstorm electrification, and some fundamental electrical properties of gases. Large uncertainties in the model inputs limit these calculations to order-or-magnitude accuracy. Despite the uncertainty, it is possible to estimate an upper limit to the efficiency of nebular discharges at melting millimeter-sized stony objects. We find that electrical arcs analogous to terrestrial lightning could have occurred in the nebula, but that under most conditions these discharges probably could not have melted chondrules. Despite our difficulties, we believe the topic worthy of further investigation and suggest some experiments which could improve our understanding of nebular discharges.

Auditory and behavioral responses of California sea lions (Zalophus californianus) to single underwater impulses from an arc-gap transducer.

PubMed

Finneran, James J; Dear, Randall; Carder, Donald A; Ridgway, Sam H

2003-09-01

A behavioral response paradigm was used to measure underwater hearing thresholds in two California sea lions (Zalophus californianus) before and after exposure to underwater impulses from an arc-gap transducer. Preexposure and postexposure hearing thresholds were compared to determine if the subjects experienced temporary shifts in their masked hearing thresholds (MTTS). Hearing thresholds were measured at 1 and 10 kHz. Exposures consisted of single underwater impulses produced by an arc-gap transducer referred to as a "pulsed power device" (PPD). The electrical charge of the PPD was varied from 1.32 to 2.77 kJ; the distance between the subject and the PPD was varied over the range 3.4 to 25 m. No MTTS was observed in either subject at the highest received levels: peak pressures of approximately 6.8 and 14 kPa, rms pressures of approximately 178 and 183 dB re: 1 microPa, and total energy fluxes of 161 and 163 dB re: 1 microPa2s for the two subjects. Behavioral reactions to the tests were observed in both subjects. These reactions primarily consisted of temporary avoidance of the site where exposure to the PPD impulse had previously occurred.

[Determination of electric field distribution in dielectric barrier surface glow discharge by spectroscopic method].

PubMed

Li, Xue-chen; Jia, Peng-ying; Liu, Zhi-hui; Li, Li-chun; Dong, Li-fang

2008-12-01

In the present paper, stable glow discharges were obtained in air at low pressure with a dielectric barrier surface discharge device. Light emission from the discharge was detected by photomultiplier tubes and the research results show that the light signal exhibited one discharge pulse per half cycle of the applied voltage. The light pulses were asymmetric between the positive half cycle and the negative one of the applied voltage. The images of the glow surface discharge were processed by Photoshop software and the results indicate that the emission intensity remained almost constant for different places with the same distance from the powered electrode, while the emission intensity decreased with the distance from the powered electrode increasing. In dielectric barrier discharge, net electric field is determined by the applied voltage and the wall charges accumulated on the dielectric layer during the discharge, and consequently, it is important to obtain information about the net electric field distribution. For this purpose, optical emission spectroscopy method was used. The distribution of the net electric field can be deduced from the intensity ratio of spectral line 391.4 nm emitted from the first negative system of N2+ (B 2sigma u+ -->X 2sigma g+) to 337.1 nm emitted from the second positive system of N2 (C 3IIu-B 3IIg). The research results show that the electric field near the powered electric field is higher than at the edge of the discharge. These experimental results are very important for numerical study and industrial application of the surface discharge.

Elemental Composition of the Powder Particles Produced by Electric Discharge Dispersion of the Wastes of a VK8 Hard Alloy

NASA Astrophysics Data System (ADS)

Latypov, R. A.; Ageev, E. V.; Latypova, G. R.; Altukhov, A. Yu.; Ageeva, E. V.

2017-12-01

The powder fabricated by electric discharge dispersion of the wastes of a VK8 hard alloy is studied by electron-probe microanalysis. This powder formed by electric discharge dispersion in kerosene mainly contains tungsten and carbon and has low contents of oxygen, cobalt, and iron.

50 CFR 660.712 - Longline fishery.

Code of Federal Regulations, 2012 CFR

2012-10-01

...° long. (7) No light stick may be possessed on board a vessel registered for use of longline gear during... light stick as used in this paragraph is any type of light emitting device, including any flourescent glow bead, chemical, or electrically powered light that is affixed underwater to the longline gear. (8...

50 CFR 660.712 - Longline fishery.

Code of Federal Regulations, 2011 CFR

2011-10-01

...° long. (7) No light stick may be possessed on board a vessel registered for use of longline gear during... light stick as used in this paragraph is any type of light emitting device, including any flourescent glow bead, chemical, or electrically powered light that is affixed underwater to the longline gear. (8...

50 CFR 660.712 - Longline fishery.

Code of Federal Regulations, 2014 CFR

2014-10-01

...° long. (7) No light stick may be possessed on board a vessel registered for use of longline gear during... light stick as used in this paragraph is any type of light emitting device, including any flourescent glow bead, chemical, or electrically powered light that is affixed underwater to the longline gear. (8...

50 CFR 660.712 - Longline fishery.

Code of Federal Regulations, 2013 CFR

2013-10-01

...° long. (7) No light stick may be possessed on board a vessel registered for use of longline gear during... light stick as used in this paragraph is any type of light emitting device, including any flourescent glow bead, chemical, or electrically powered light that is affixed underwater to the longline gear. (8...

Lightning and middle atmospheric discharges in the atmosphere

NASA Astrophysics Data System (ADS)

Siingh, Devendraa; Singh, R. P.; Kumar, Sarvan; Dharmaraj, T.; Singh, Abhay K.; Singh, Ashok K.; Patil, M. N.; Singh, Shubha

2015-11-01

Recent development in lightning discharges including transient luminous events (TLEs) and global electric circuit are discussed. Role of solar activity, convective available potential energy, surface temperature and difference of land-ocean surfaces on convection process are discussed. Different processes of discharge initiation are discussed. Events like sprites and halos are caused by the upward quasi-electrostatic fields associated with intense cloud-to-ground discharges while jets (blue starter, blue jet, gigantic jet) are caused by charge imbalance in thunderstorm during lightning discharges but they are not associated with a particular discharge flash. Elves are generated by the electromagnetic pulse radiated during lightning discharges. The present understanding of global electric circuit is also reviewed. Relation between lightning activity/global electric circuit and climate is discussed.

Effects of Electric Discharge Plasma Treatment on the Thermal Conductivity of Polymer-Metal Nitride/Carbide Composites

NASA Astrophysics Data System (ADS)

Parali, Levent; Kurbanov, Mirza A.; Bayramov, Azad A.; Tatardar, Farida N.; Sultanakhmedova, Ramazanova I.; Xanlar, Huseynova Gulnara

2015-11-01

High-density polymer composites with semiconductor or dielectric fillers such as aluminum nitride (AIN), aluminum oxide (Al2O3), titanium carbide (TiC), titanium nitride (TiN), boron nitride (BN), silicon nitride (Si3N4), and titanium carbonitride (TiCN) were prepared by the hot pressing method. Each powder phase of the composites was exposed to an electric discharge plasma process before composite formation. The effects of the electric discharge plasma process and the filler content (volume fraction) on the thermal conductivity, volt-ampere characteristics, thermally stimulated depolarization current, as well as electrical and mechanical strength were investigated. The results of the study indicate that, with increasing filler volume fraction, the thermal conductivity of the samples also increased. Furthermore, the thermal conductivity, and electrophysical and mechanical properties of the high-density polyethylene + 70% BN composite modified using the electric discharge plasma showed improvement when compared with that without electric discharge plasma treatment.

Plasma rotation by electric and magnetic fields in a discharge cylinder

NASA Technical Reports Server (NTRS)

Wilhelm, H. E.; Hong, S. H.

1977-01-01

A theoretical model for an electric discharge consisting of a spatially diverging plasma sustained electrically between a small ring cathode and a larger ring anode in a cylindrical chamber with an axial magnetic field is developed to study the rotation of the discharge plasma in the crossed electric and magnetic fields. The associated boundary-value problem for the coupled partial differential equations which describe the electric potential and the plasma velocity fields is solved in closed form. The electric field, current density, and velocity distributions are discussed in terms of the Hartmann number and the Hall coefficient. As a result of Lorentz forces, the plasma rotates with speeds as high as 1 million cm/sec around its axis of symmetry at typical conditions. As an application, it is noted that rotating discharges of this type could be used to develop a high-density plasma-ultracentrifuge driven by j x B forces, in which the lighter (heavier) ion and atom components would be enriched in (off) the center of the discharge cylinder.

High-altitude electrical discharges associated with thunderstorms and lightning

NASA Astrophysics Data System (ADS)

Liu, Ningyu; McHarg, Matthew G.; Stenbaek-Nielsen, Hans C.

2015-12-01

The purpose of this paper is to introduce electrical discharge phenomena known as transient luminous events above thunderstorms to the lightning protection community. Transient luminous events include the upward electrical discharges from thunderstorms known as starters, jets, and gigantic jets, and electrical discharges initiated in the lower ionosphere such as sprites, halos, and elves. We give an overview of these phenomena with a focus on starters, jets, gigantic jets, and sprites, because similar to ordinary lightning, streamers and leaders are basic components of these four types of transient luminous events. We present a few recent observations to illustrate their main properties and briefly review the theories. The research in transient luminous events has not only advanced our understanding of the effects of thunderstorms and lightning in the middle and upper atmosphere, but also improved our knowledge of basic electrical discharge processes critical for sparks and lightning.

Response of nickel to zinc cells to electric vehicle chopper discharge waveforms

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1981-01-01

The preliminary results of simulated electric vehicle chopper controlled discharge of a Nickel/Zinc battery shows delivered energy increases of 5 to 25 percent compared to constant current discharges of the same average current. The percentage increase was a function of chopper frequency, the ratio of peak to average current, and the magnitude of the discharge current. Because the chopper effects are of a complex nature, electric vehicle battery/speed controller interaction must be carefully considered in vehicle design to optimize battery performance.

Application of Microsecond Voltage Pulses for Water Disinfection by Diaphragm Electric Discharge

NASA Astrophysics Data System (ADS)

Kakaurov, S. V.; Suvorov, I. F.; Yudin, A. S.; Solovyova, T. L.; Kuznetsova, N. S.

2015-11-01

The paper presents the dependence of copper and silver ions formation on the duration of voltage pulses of diaphragm electric discharge and on the pH of treated liquid medium. Knowing it allows one to create an automatic control system to control bactericidal agent's parameters obtained in diaphragm electric discharge reactor. The current-voltage characteristic of the reactor with a horizontal to the diaphragm membrane water flow powered from the author's custom pulse voltage source is also presented. The results of studies of the power consumption of diaphragm electric discharge depending on temperature of the treated liquid medium are given.

Wire electric-discharge machining and other fabrication techniques

NASA Technical Reports Server (NTRS)

Morgan, W. H.

1983-01-01

Wire electric discharge machining and extrude honing were used to fabricate a two dimensional wing for cryogenic wind tunnel testing. Electric-discharge cutting is done with a moving wire electrode. The cut track is controlled by means of a punched-tape program and the cutting feed is regulated according to the progress of the work. Electric-discharge machining involves no contact with the work piece, and no mechanical force is exerted. Extrude hone is a process for honing finish-machined surfaces by the extrusion of an abrasive material (silly putty), which is forced through a restrictive fixture. The fabrication steps are described and production times are given.

Synergistic responses of superficial chemistry and micro topography of titanium created by wire-type electric discharge machining.

PubMed

Kataoka, Yu; Tamaki, Yukimichi; Miyazaki, Takashi

2011-01-01

Wire-type electric discharge machining has been applied to the manufacture of endosseous titanium implants as this computer associated technique allows extremely accurate complex sample shaping with an optimal micro textured surface during the processing. Since the titanium oxide layer is sensitively altered by each processing, the authors hypothesized that this technique also up-regulates biological responses through the synergistic effects of the superficial chemistry and micro topography. To evaluate the respective in vitro cellular responses on the superficial chemistry and micro topography of titanium surface processed by wire-type electric discharge, we used titanium-coated epoxy resin replica of the surface. An oxide layer on the titanium surface processed by wire-type electric discharge activated the initial responses of osteoblastic cells through an integrin-mediated mechanism. Since the mRNA expression of ALP on those replicas was up-regulated compared to smooth titanium samples, the micro topography of a titanium surface processed by wire-type electric discharge promotes the osteogenic potential of cells. The synergistic response of the superficial chemistry and micro topography of titanium processed by wire-type electric discharge was demonstrated in this study.

Remote environmental sensor array system

NASA Astrophysics Data System (ADS)

Hall, Geoffrey G.

This thesis examines the creation of an environmental monitoring system for inhospitable environments. It has been named The Remote Environmental Sensor Array System or RESA System for short. This thesis covers the development of RESA from its inception, to the design and modeling of the hardware and software required to make it functional. Finally, the actual manufacture, and laboratory testing of the finished RESA product is discussed and documented. The RESA System is designed as a cost-effective way to bring sensors and video systems to the underwater environment. It contains as water quality probe with sensors such as dissolved oxygen, pH, temperature, specific conductivity, oxidation-reduction potential and chlorophyll a. In addition, an omni-directional hydrophone is included to detect underwater acoustic signals. It has a colour, high-definition and a low-light, black and white camera system, which it turn are coupled to a laser scaling system. Both high-intensity discharge and halogen lighting system are included to illuminate the video images. The video and laser scaling systems are manoeuvred using pan and tilt units controlled from an underwater computer box. Finally, a sediment profile imager is included to enable profile images of sediment layers to be acquired. A control and manipulation system to control the instruments and move the data across networks is integrated into the underwater system while a power distribution node provides the correct voltages to power the instruments. Laboratory testing was completed to ensure that the different instruments associated with the RESA performed as designed. This included physical testing of the motorized instruments, calibration of the instruments, benchmark performance testing and system failure exercises.

Natural Underwater Adhesives

PubMed Central

Stewart, Russell J.; Ransom, Todd C.; Hlady, Vladimir

2011-01-01

The general topic of this review is protein-based underwater adhesives produced by aquatic organisms. The focus is on mechanisms of interfacial adhesion to native surfaces and controlled underwater solidification of natural water-borne adhesives. Four genera that exemplify the broad range of function, general mechanistic features, and unique adaptations are discussed in detail: blue mussels, acorn barnacles, sandcastle worms, and freshwater caddisfly larva. Aquatic surfaces in nature are charged and in equilibrium with their environment, populated by an electrical double layer of ions as well as adsorbed natural polyelectrolytes and microbial biofilms. Surface adsorption of underwater bioadhesives likely occurs by exchange of surface bound ligands by amino acid sidechains, driven primarily by relative affinities and effective concentrations of polymeric functional groups. Most aquatic organisms exploit modified amino acid sidechains, in particular phosphorylated serines and hydroxylated tyrosines (dopa), with high-surface affinity that form coordinative surface complexes. After delivery to the surfaces as a fluid, permanent natural adhesives solidify to bear sustained loads. Mussel plaques are assembled in a manner superficially reminiscent of in vitro layer-by-layer strategies, with sequentially delivered layers associated through Fe(dopa)3 coordination bonds. The adhesives of sandcastle worms, caddisfly larva, and barnacles may be delivered in a form somewhat similar to in vitro complex coacervation. Marine adhesives are secreted, or excreted, into seawater that has a significantly higher pH and ionic strength than the internal environment. Empirical evidence suggests these environment triggers could provide minimalistic, fail-safe timing mechanisms to prevent premature solidification (insolubilization) of the glue within the secretory system, yet allow rapid solidification after secretion. Underwater bioadhesives are further strengthened by secondary covalent curing. PMID:21643511

Response of lead-acid batteries to chopper-controlled discharge. [for electric vehicles

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1978-01-01

The results of tests on an electric vehicle battery, using a simulated electric vehicle chopper-speed controller, show energy output losses up to 25 percent compared to constant current discharges at the same average current of 100 A. However, an energy output increase of 22 percent is noticed at the 200 A average level and 44 percent increase at the 300 A level using pulse discharging. Because of these complex results, electric vehicle battery/speed controller interactions must be considered in vehicle design.

Stability of imploding shocks generated by underwater electrical explosion of cylindrical wire array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozlov, M.; Gurovich, V. Tz.; Krasik, Ya. E.

2013-11-15

The results of two-dimensional hydrodynamic simulations of the dynamics and stability of azimuthal non-uniformities in converging shock waves generated by an underwater explosion of a cylindrical wire array and their effect on the cumulation of energy in the vicinity of the converging axis are presented. It has been shown that in spite of the fact that such non-uniformities are always weakly unstable, for a broad range of experimentally relevant regimes these non-uniformities remain small and do not significantly affect the cumulation of energy. Only the non-uniformities with wavelengths comparable to the distance from the axis of convergence exhibit substantial growthmore » that considerably attenuates the energy cumulation.« less

50 CFR 665.800 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... no light sticks are used. As used in this definition, “float line” means a line used to suspend the main longline beneath a float, and “light stick” means any type of light emitting device, including any fluorescent “glow bead,” chemical, or electrically-powered light that is affixed underwater to the longline...

50 CFR 665.800 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... no light sticks are used. As used in this definition, “float line” means a line used to suspend the main longline beneath a float, and “light stick” means any type of light emitting device, including any fluorescent “glow bead,” chemical, or electrically-powered light that is affixed underwater to the longline...

50 CFR 665.800 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... no light sticks are used. As used in this definition, “float line” means a line used to suspend the main longline beneath a float, and “light stick” means any type of light emitting device, including any fluorescent “glow bead,” chemical, or electrically-powered light that is affixed underwater to the longline...

Evaluation of Potential Military Applications of Stirling Engines

DTIC Science & Technology

1988-07-01

ES- 1 C. Generator Sn-,s (Mobile Electric Power) ..................................... ES-3 1. General Purpose...ES-2 ES-2. General Purpose Generator Sets in the US DoD Inventory ..................... ES-4 ES-3. Comparison of Typical Diesel Engines Used in DoD...Standard Family Generator Sets and Stirling Engines ....................................... ES-4 ES-4. Underwater Energy Storage

Jackson, Todd, and the concept of "discharge" in epilepsy.

PubMed

Reynolds, Edward H

2007-11-01

To explore the historical origins of the modern concept of electrical discharges in the brain in epilepsy. I have examined the writings of Hughlings Jackson (1835-1911) and Robert Bentley Todd (1809-1860), especially their Lumleian Lectures on convulsive disorders to the Royal College of Physicians of 1890 and 1849, respectively; and also the influence of Herbert Spencer (1820-1903) on the former and Michael Faraday (1791-1867) on the latter. Contrary to the widely taught view that Jackson was the first to propose electrical discharges in epilepsy it is clear that the discharges suggested by Jackson, influenced by the evolutionary philosopher, Herbert Spencer, were chemical, based on katabolism and anabolism. Jackson had no understanding or proposal based on physics or electricity. On the other hand, Todd had earlier proposed and described electrical concepts of discharges in epilepsy, influenced by his contemporary and colleague in London, Michael Faraday, who at the time was laying the foundations of our modern understanding of electricity and magnetism. Todd and Faraday saw "nervous polarity" as another polar force interchangeable with the polar forces of electricity and magnetism.

Convergence of shock waves generated by underwater electrical explosion of cylindrical wire arrays between different boundary geometries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yanuka, D.; Zinowits, H. E.; Krasik, Ya. E.

The results of experiments and numerical simulations of a shock wave propagating between either conical or parabolic bounding walls are presented. The shock wave was generated by a microsecond timescale underwater electrical explosion of a cylindrical wire array supplied by a current pulse having an amplitude of ∼230 kA and a rise time of ∼1 μs. It is shown that with the same energy density deposition into the exploding wire array, the shock wave converges faster between parabolic walls, and as a result, the pressure in the vicinity of convergence is ∼2.3 times higher than in the case of conical walls. Themore » results obtained are compared to those of earlier experiments [Antonov et al., Appl. Phys. Lett. 102, 124104 (2013)] with explosions of spherical wire arrays. It is shown that at a distance of ∼400 μm from the implosion origin the pressure obtained in the current experiments is higher than for the case of spherical wire arrays.« less

Characterization of electrical discharges on Teflon dielectrics used as spacecraft thermal control

NASA Technical Reports Server (NTRS)

Yadlowsky, E. J.; Hazelton, R. C.; Churchill, R. J.

1979-01-01

The dual effects of system degradation and reduced life of synchronous-orbit satellites as a result of differential spacecraft charging underscore the need for a clearer understanding of the prevailing electrical discharge phenomena. In a laboratory simulation, the electrical discharge current, surface voltage, emitted particle fluxes, and photo-emission associated with discharge events on electron beam irradiated silver-backed Teflon samples were measured. Sample surface damage was examined with optical and electron beam microscopes. The results are suggestive of a model in which the entire sample surface is discharged by lateral sub-surface currents flowing from a charge deposition layer through a localized discharge channel to the back surface of the sample. The associated return current pulse appears to have a duration which may be a signature by which different discharge processes may be characterized.

Process Properties of Electronic High Voltage Discharges Triggered by Ultra-short Pulsed Laser Filaments

NASA Astrophysics Data System (ADS)

Cvecek, Kristian; Gröschel, Benjamin; Schmidt, Michael

Remote processing of metallic workpieces by techniques based on electric arc discharge or laser irradiation for joining or cutting has a long tradition and is still being intensively investigated in present-day research. In applications that require high power processing, both approaches exhibit certain advantages and disadvantages that make them specific for a given task. While several hybrid approaches exist that try to combine the benefits of both techniques, none were as successful in providing a fixed electric discharge direction as discharges triggered by plasma filaments generated by ultra-short pulsed lasers. In this work we investigate spatial and temporal aspects of laser filament guided discharges and give an upper time delay between the filament creation and the electrical build-up of a dischargeable voltage for a successful filament triggered discharge.

Active Electro-Location of Objects in the Underwater Environment Based on the Mixed Polarization Multiple Signal Classification Algorithm

PubMed Central

Guo, Lili; Qi, Junwei; Xue, Wei

2018-01-01

This article proposes a novel active localization method based on the mixed polarization multiple signal classification (MP-MUSIC) algorithm for positioning a metal target or an insulator target in the underwater environment by using a uniform circular antenna (UCA). The boundary element method (BEM) is introduced to analyze the boundary of the target by use of a matrix equation. In this method, an electric dipole source as a part of the locating system is set perpendicularly to the plane of the UCA. As a result, the UCA can only receive the induction field of the target. The potential of each electrode of the UCA is used as spatial-temporal localization data, and it does not need to obtain the field component in each direction compared with the conventional fields-based localization method, which can be easily implemented in practical engineering applications. A simulation model and a physical experiment are constructed. The simulation and the experiment results provide accurate positioning performance, with the help of verifying the effectiveness of the proposed localization method in underwater target locating. PMID:29439495

Effect of Electric Discharge on Properties of Nano-Particulate Catalyst for Plasma-Catalysis.

PubMed

Lee, Chung Jun; Kim, Jip; Kim, Taegyu

2016-02-01

Heterogeneous catalytic processes have been used to produce hydrogen from hydrocarbons. However, high reforming temperature caused serious catalyst deteriorations and low energy efficiency. Recently, a plasma-catalyst hybrid process was used to reduce the reforming temperature and to improve the stability and durability of reforming catalysts. Effect of electric discharges on properties of nanoparticulate catalysts for plasma-catalysis was investigated in the present study. Catalyst-bed porosity was varied by packing catalyst beads with the different size in a reactor. Discharge power and onset voltage of the plasma were measured as the catalyst-bed porosity was varied. The effect of discharge voltage, frequency and voltage waveforms such as the sine, pulse and square was investigated. We found that the optimal porosity of the catalyst-bed exists to maximize the electric discharge. At a low porosity, the electric discharge was unstable to be sustained because the space between catalysts got narrow nearly close to the sheath region. On the other hand, at a high porosity, the electric discharge became weak because the plasma was not sufficient to interact with the surface of catalysts. The discharge power increased as the discharge voltage and frequency increased. The square waveform was more efficient than the sine and pulse one. At a high porosity, however, the effect of the voltage waveform was not considerable because the space between catalysts was too large for plasma to interact with the surface of catalysts.

A proposed national wind power R and D program. [offshore wind power system for electric energy supplies

NASA Technical Reports Server (NTRS)

Heronemus, W.

1973-01-01

An offshore wind power system is described that consists of wind driven electrical dc generators mounted on floating towers in offshore waters. The output from the generators supplies underwater electrolyzer stations in which water is converted into hydrogen and oxygen. The hydrogen is piped to shore for conversion to electricity in fuel cell stations. It is estimated that this system can produce 159 x 10 to the ninth power kilowatt-hours per year. It is concluded that solar energy - and that includes wind energy - is the only way out of the US energy dilemma in the not too distant future.

Lightning Discharges to Aircraft and Associated Meteorological Conditions

NASA Technical Reports Server (NTRS)

Harrison, L P

1946-01-01

A summary is given of information on atmospheric electrical discharges to aircraft and associated meteorological conditions. Information is given that is designed to give a fairly comprehensive view of the underlying principles of meteorology and atmospheric electricity. Of special interest to pilots are lists of procedures of flight conduct and aircraft maintenance recommended foe avoiding or minimizing the hazards of disruptive electrical discharges and other severe conditions near thunderstorms.

Pulsed electrical discharge in gas bubbles in water

NASA Astrophysics Data System (ADS)

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 compared to the traditional corona or dielectric barrier discharges. These conditions make the experimental evidence presented in this work valuable for the advancement of modeling and the theoretical understanding of the discharge in bubbles in water.

Potential efficiencies of open- and closed-cycle CO, supersonic, electric-discharge lasers

NASA Technical Reports Server (NTRS)

Monson, D. J.

1976-01-01

Computed open- and closed-cycle system efficiencies (laser power output divided by electrical power input) are presented for a CW carbon monoxide, supersonic, electric-discharge laser. Closed-system results include the compressor power required to overcome stagnation pressure losses due to supersonic heat addition and a supersonic diffuser. The paper shows the effect on the system efficiencies of varying several important parameters. These parameters include: gas mixture, gas temperature, gas total temperature, gas density, total discharge energy loading, discharge efficiency, saturated gain coefficient, optical cavity size and location with respect to the discharge, and supersonic diffuser efficiency. Maximum open-cycle efficiency of 80-90% is predicted; the best closed-cycle result is 60-70%.

[Experimental study of the effects of impulse-electric discharge on chemotaxis and cytoadhesion of urinary infection pathogens].

PubMed

Kuderinov, S K; Azizov, I S; Turgunov, E M; Shambilova, N A

2006-01-01

The aim of the experimental study was to evaluate effects of impulse-electric discharge in liquid on chemotaxis and cytoadhesion of urinary infection pathogens. Chemotaxis was determined in respect to the lung, liver, spleen, kidney, ureter, urinary bladder, urethra of white mice by S. Likholetov's modified method. Cytoadhesion was assessed by V. Brilis. The experiments show that the impulse-electric discharge holds promise for urological practice.

Underwater Chaotic Lidar using Blue Laser Diodes

NASA Astrophysics Data System (ADS)

Rumbaugh, Luke K.

The thesis proposes and explores an underwater lidar system architecture based on chaotic modulation of recently introduced, commercially available, low cost blue laser diodes. This approach is experimentally shown to allow accurate underwater impulse response measurements while eliminating the need for several major components typically found in high-performance underwater lidar systems. The proposed approach is to: 1. Generate wideband, noise-like intensity modulation signals using optical chaotic modulation of blue-green laser diodes, and then 2. Use this signal source to develop an underwater chaotic lidar system that uses no electrical signal generator, no electro-optic modulator, no optical frequency doubler, and no large-aperture photodetector. The outcome of this thesis is the demonstration of a new underwater lidar system architecture that could allow high resolution ranging, imaging, and water profiling measurements in turbid water, at a reduced size, weight, power and cost relative to state-of-the-art high-performance underwater lidar sensors. This work also makes contributions to the state of the art in optics, nonlinear dynamics, and underwater sensing by demonstrating for the first time: 1. Wideband noise-like intensity modulation of a blue laser diode using no electrical signal generator or electro-optic modulator. Optical chaotic modulation of a 462 nm blue InGaN laser diode by self-feedback is explored for the first time. The usefulness of the signal to chaotic lidar is evaluated in terms of bandwidth, modulation depth, and autocorrelation peak-to-sidelobe-ratio (PSLR) using both computer and laboratory experiments. In laboratory experiments, the optical feedback technique is shown to be effective in generating wideband, noise-like chaotic signals with strong modulation depth when the diode is operated in an external-cavity dominated state. The modulation signal strength is shown to be limited by the onset of lasing within the diode's internal cavity. The possibility of overcoming this limit by increasing optical feedback strength is discussed. 2. Power scaling in the blue-green spectrum using no optical frequency doubler. Synchronization of two 462 nm blue InGaN laser diodes by bi-directional optical injection is demonstrated for the first time in laboratory experiments. The improvement in chaotic intensity modulation signal strength is demonstrated to be 2.5x over the single-diode case. The signal strength is again shown to be limited by the onset of internal cavity lasing. The synchronized-laser arrangement is shown to be theoretically equivalent to a single-diode scenario in which the optical feedback is amplified by 2x, supporting the idea that increased optical feedback strength can be used to scale optical chaotic modulation of InGaN diodes to high powers. 3. Underwater impulse response measurements using a calibrated chaotic lidar system. An underwater chaotic lidar system using two synchronized diodes as transmitters is demonstrated in laboratory experiments for the first time. Reflective impulse response measurements using the lidar system are made in free space, and in a variety of clear and turbid water conditions, using a quasi-monostatic (i.e. co-located transmitter and receiver) arrangement. A calibration routine is implemented that increases accuracy and instantaneous dynamic range of the impulse response measurement, resulting in a baseline temporal resolution of 750 ps and a PSLR of over 10 dB. The calibrated system is shown to be able to simultaneously measure localized and distributed reflections, and to allow separation of the localized ( i.e. surface and target) reflections from the distributed ( i.e. backscatter) returns in several domains. Accurate range measurement with sub-inch typical error is demonstrated in laboratory water tank tests, which show accurate measurement through >6 feet of turbid water, as limited by the experimental water tank setup. Strong performance to the limit of the setup is shown at dwell times down to 1 mus. 4. Range measurement through turbid water using no large-aperture photodetector. The possibility of using a synchronized optical receiver to make range measurements through an attenuating channel (i.e. turbid water) is tested using two InGaN diodes for the first time. Using a variable optical attenuator to simulate channel attenuation, synchronization is maintained through 30 dB channel attenuation in the current experimental setup. Distance measurements are demonstrated by using the output of only one of the two diodes, suggesting that this method could be used to measure distance between two bi-static (i.e. physically separated), cooperative chaotic lidar systems in some water conditions. This thesis concludes that the proposed approach is a feasible path to a novel high resolution underwater lidar sensor capable of operating in turbid water, which would have significant size, weight, power, and cost reductions because it would not use an electrical signal generator, an electro-optic modulator, or an optical frequency doubler. The work also suggests the possibility of range measurement in a limited range of water conditions using no large-aperture photodetector, most feasibly in a bi-static cooperative arrangement.

Electrical Breakdown Phenomena Involving Material Interfaces

DTIC Science & Technology

2013-06-01

create ozone through chemical reactions involving reactive species created by the electrical discharge [3]. The glow discharge breakdown in such...2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Investigation Of Pre-Ionization And Atmospheric Pulsed Discharge Plasma 5a...growth of the air discharge in the form of a conductive filament consisting of electrons and ions. This filament is created by temporal pulse that

Theoretical Investigations of Dielectric Breakdown in CO2: Implications for Atmospheric Discharges on Mars (and Venus)

NASA Astrophysics Data System (ADS)

Riousset, J. A.

2017-12-01

The detection of an atmospheric discharge in the Martian atmosphere by Ruf et al. [GRL, 36, L13202, 2009] supports the idea of a Martian atmospheric electric circuit [Farrell and Desch, JGR, 106, E4, 2001]. However, the lack of subsequent detection of similar events raises the question of the conditions of their initiation, and the existence of Martian lightning remains a controversial question. On Earth, atmospheric electricity manifests itself in the form of glow, corona, streamer, and leader discharges observed as Saint Elmo's fire, sprites, lightning and jets discharges, and other Transient Luminous Events (TLEs). All of these are dielectric breakdown governed by different physics. Their initiation is associated with the crossing of specific electric field thresholds: relativistic runaway, streamer propagation, conventional breakdown, or thermal runaway thresholds, some better understood than others. For example, the initiation of a lightning discharge is known to occur when the local electric field exceeds a value similar to relativistic runaway field, but the exact threshold, as well as the physical mechanisms at work, remain unclear to date. Scaling laws for electric fields (and other quantities) have been established by Pasko et al. [GRL, 25(12), 2123-2126, 1998] and Pasko [NATO Sci. Series, Springer, 253-311, 2006]. In this work, we develop profiles for initiation criteria in air and in other atmospheric environments. We further calculate their associated scaling laws to determine the ability to trigger lightning flashes and TLEs on Mars. This lets us predict the likelihood of electrical discharges and calculate the expected electric field conditions, under which discharges could be observed. We develop the analogy between Earth sand storm [Nicoll et al., Env. Res. Lett., 6, 014001, 2001] and Martian dust storms [Melnik and Parrot, JGR, 103(A12), 1998] to investigate the charge structure and resulting electric fields necessary to initiate dielectric breakdown in the Martian atmosphere. Initiation of electric discharges will be susceptible to local pressure, density, atmospheric composition, and charge structure, and will impact charge moment variations detectable by remote sensing.

Dynamic generation of supercritical water fluid in a strong electrical discharge in a liquid

NASA Astrophysics Data System (ADS)

Antonov, V.; Kalinin, N.; Kovalenko, A.

2016-11-01

A new impetus for the development of electro physics is associated with using different types of electrical discharges in biology and medicine. These applications are based on their energetic and non-toxic factors affecting the medium on a cellular level. For the study of such processes, a mathematical model of a high-current low-temperature Z-discharge in a liquid, forming by the electrical explosion of a thin-walled metal shell, connected to a pulsed high-voltage generator, has been developed. High efficiency energy conversion, introduced into the plasma discharge to the energy of fluid motion, provides various bio chemical applications of such physical processes. The investigation is conducted through numerical solution of one-dimensional single-temperature non-stationary equations of radiation magneto hydrodynamics, one way describing the evolution of hydrodynamic, thermal and electrical characteristics of the medium throughout the area under consideration. The electrical approximation based on the assumption that the electric field in the discharge has a uniform distribution. The results are presented as a function of the electric current and the plasma channel length of time, as well as the temperature and pressure distributions at different time points along the radius of the cylindrical region in which the explosion occurs.

Professor Joseph Warren Horton (1889-1967): biological engineer.

PubMed

Zeitlin, Gerald L

2005-02-01

Joseph Warren Horton graduated with a degree in electrical engineering from the Massachusetts Institute of Technology (MIT) in 1914. He became involved in the early development of electrical measurement devices, televised image transmission, and the detection of underwater sound transmission. In the mid-1930s he was appointed the first leader of the newly created Department of Biological Engineering at MIT and in this position he made major contributions to the application of physics to human physiology, in particular by increasing the safety of explosive inhalational anaesthetic agents.

Flight Termination Systems Commonality Standard

DTIC Science & Technology

2014-09-01

input level is increased 60 dB from threshold. Corona : A visible electric discharge resulting from a partial electric breakdown of gases as the...4-49 Figure 4-10. Electrostatic Discharge Test...check channel telemetry output (EFTR) CDR critical design review CFS flight self- discharge in amp-hrs CR remaining capacity for determining

Conversion of NO to NO(2) in air by a micro electric NO(x) converter based on a corona discharge process.

PubMed

Yoon, Seung-Il; Heo, Sungmoo; Song, Soonho; Kim, Yong-Jun

2010-06-01

A micro-electric-NO(x)-converter based on volume treatment is proposed for the evaluation of NO(x) concentrations in air. It can electrically convert NO(x) mixture from variable mixing rates into a fixed-mixing rate of 25% NO(2) and 75% NO using the corona discharge process with stable conversion efficiency and high throughput (space velocity = 6.3 x 10(4) h(-1)). The micro-electric-NO(x)-converter is based on a volume process. Applying high voltage to the electrodes of the micro-electric-NO(x)-converter generates a corona discharge. This discharge creates high-energy electrons, which collide with gas molecules. After these collisions, NO and O(2) are broken into single atoms, and they are re-combined as a balanced form, NO(2) in this case. The fabricated micro-electric-NO(x)-converter converted NO into NO(2) at conversion efficiency of 25.63%, when 5.5 kV (the applied corona power = 0.196 W) was applied to the micro-electric-NO(x)-converter.

Electric Discharge Sintering and Joining of Tungsten Carbide—Cobalt Composite with High-Speed Steel Substrate

NASA Astrophysics Data System (ADS)

Grigoryev, Evgeny G.

2011-01-01

Simultaneous electro discharge sintering of high strength structure of tungsten carbide—cobalt composite and connection it with high-speed steel substrate is investigated and suitable operating parameters are defined. Tungsten carbide—cobalt and high-speed steel joining was produced by the method of high voltage electrical discharge together with application of mechanical pressure to powder compact. It was found that the density and hardness of composite material reach its maximum values at certain magnitudes of applied pressure and high voltage electrical discharge parameters. We show that there is an upper level for the discharge voltage beyond which the powder of composite material disintegrates like an exploding wire. Due to our results it is possible to determine optimal parameters for simultaneous electro discharge sintering of WC-Co and bonding it with high-speed steel substrate.

Efficient 'Foton' electric-discharge KrCl laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panchenko, Aleksei N; Tarasenko, Viktor F

The design of the 'Foton' electric-discharge laser, optimised for operation on the basis of KrCl* molecules, and its energy parameters were investigated. At {lambda} = 222 nm the radiation energy was up to 250 mJ per pulse. The specific output radiation energy was 2.5 J litre{sup -1} and the laser efficiency was in excess of 0.8%. The possibility of further improvement of the characteristics of electric-discharge KrCl lasers are discussed. (lasers)

Discharging a DC bus capacitor of an electrical converter system

DOEpatents

Kajouke, Lateef A; Perisic, Milun; Ransom, Ray M

2014-10-14

A system and method of discharging a bus capacitor of a bidirectional matrix converter of a vehicle are presented here. The method begins by electrically shorting the AC interface of the converter after an AC energy source is disconnected from the AC interface. The method continues by arranging a plurality of switching elements of a second energy conversion module into a discharge configuration to establish an electrical current path from a first terminal of an isolation module, through an inductive element, and to a second terminal of the isolation module. The method also modulates a plurality of switching elements of a first energy conversion module, while maintaining the discharge configuration of the second energy conversion module, to at least partially discharge a DC bus capacitor.

Offshore windmills and the effects of electromagnetic fields on fish.

PubMed

Ohman, Marcus C; Sigray, Peter; Westerberg, Håkan

2007-12-01

With the large scale developments of offshore windpower the number of underwater electric cables is increasing with various technologies applied. A wind farm is associated with different types of cables used for intraturbine, array-to-transformer, and transformer-to-shore transmissions. As the electric currents in submarine cables induce electromagnetic fields there is a concern of how they may influence fishes. Studies have shown that there are fish species that are magneto-sensitive using geomagnetic field information for the purpose of orientation. This implies that if the geomagnetic field is locally altered it could influence spatial patterns in fish. There are also physiological aspects to consider, especially for species that are less inclined to move as the exposure could be persistent in a particular area. Even though studies have shown that magnetic fields could affect fish, there is at present limited evidence that fish are influenced by the electromagnetic fields that underwater cables from windmills generate. Studies on European eel in the Baltic Sea have indicated some minor effects. In this article we give an overview on the type of submarine cables that are used for electric transmissions in the sea. We also describe the character of the magnetic fields they induce. The effects of magnetic fields on fish are reviewed and how this may relate to the cables used for offshore wind power is discussed.

78 FR 34431 - Effluent Limitations Guidelines and Standards for the Steam Electric Power Generating Point...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-07

...EPA is proposing a regulation that would strengthen the controls on discharges from certain steam electric power plants by revising technology-based effluent limitations guidelines and standards for the steam electric power generating point source category. Steam electric power plants alone contribute 50-60 percent of all toxic pollutants discharged to surface waters by all industrial categories currently regulated in the United States under the Clean Water Act. Furthermore, power plant discharges to surface waters are expected to increase as pollutants are increasingly captured by air pollution controls and transferred to wastewater discharges. This proposal, if implemented, would reduce the amount of toxic metals and other pollutants discharged to surface waters from power plants. EPA is considering several regulatory options in this rulemaking and has identified four preferred alternatives for regulation of discharges from existing sources. These four preferred alternatives differ with respect to the scope of requirements that would be applicable to existing discharges of pollutants found in two wastestreams generated at power plants. EPA estimates that the preferred options for this proposed rule would annually reduce pollutant discharges by 0.47 billion to 2.62 billion pounds, reduce water use by 50 billion to 103 billion gallons, cost $185 million to $954 million, and would be economically achievable.

Characterization of Microwave-Induced Electric Discharge Phenomena in Metal–Solvent Mixtures

PubMed Central

Chen, Wen; Gutmann, Bernhard; Kappe, C Oliver

2012-01-01

Electric discharge phenomena in metal–solvent mixtures are investigated utilizing a high field density, sealed-vessel, single-mode 2.45 GHz microwave reactor with a built-in camera. Particular emphasis is placed on studying the discharges exhibited by different metals (Mg, Zn, Cu, Fe, Ni) of varying particle sizes and morphologies in organic solvents (e.g., benzene) at different electric field strengths. Discharge phenomena for diamagnetic and paramagnetic metals (Mg, Zn, Cu) depend strongly on the size of the used particles. With small particles, short-lived corona discharges are observed that do not lead to a complete breakdown. Under high microwave power conditions or with large particles, however, bright sparks and arcs are experienced, often accompanied by solvent decomposition and formation of considerable amounts of graphitized material. Small ferromagnetic Fe and Ni powders (<40 μm) are heated very rapidly in benzene suspensions and start to glow in the microwave field, whereas larger particles exhibit extremely strong discharges. Electric discharges were also observed when Cu metal or other conductive materials such as silicon carbide were exposed to the microwave field in the absence of a solvent in an argon or nitrogen atmosphere. PMID:24551491

Characterization of microwave-induced electric discharge phenomena in metal-solvent mixtures.

PubMed

Chen, Wen; Gutmann, Bernhard; Kappe, C Oliver

2012-02-01

Electric discharge phenomena in metal-solvent mixtures are investigated utilizing a high field density, sealed-vessel, single-mode 2.45 GHz microwave reactor with a built-in camera. Particular emphasis is placed on studying the discharges exhibited by different metals (Mg, Zn, Cu, Fe, Ni) of varying particle sizes and morphologies in organic solvents (e.g., benzene) at different electric field strengths. Discharge phenomena for diamagnetic and paramagnetic metals (Mg, Zn, Cu) depend strongly on the size of the used particles. With small particles, short-lived corona discharges are observed that do not lead to a complete breakdown. Under high microwave power conditions or with large particles, however, bright sparks and arcs are experienced, often accompanied by solvent decomposition and formation of considerable amounts of graphitized material. Small ferromagnetic Fe and Ni powders (<40 μm) are heated very rapidly in benzene suspensions and start to glow in the microwave field, whereas larger particles exhibit extremely strong discharges. Electric discharges were also observed when Cu metal or other conductive materials such as silicon carbide were exposed to the microwave field in the absence of a solvent in an argon or nitrogen atmosphere.

Estimation of the ionic charge of non-metallic species into an electrical discharge through a web application

NASA Astrophysics Data System (ADS)

Pérez Gutiérrez, B. R.; Vera-Rivera, F. H.; Niño, E. D. V.

2016-08-01

Estimate the ionic charge generated in electrical discharges will allow us to know more accurately the concentration of ions implanted on the surfaces of nonmetallic solids. For this reason, in this research a web application was developed to allow us to calculate the ionic charge generated in an electrical discharge from the experimental parameters established in an ion implantation process performed in the JUPITER (Joint Universal Plasma and Ion Technologies Experimental Reactor) reactor. The estimated value of the ionic charge will be determined from data acquired on an oscilloscope, during startup and shutdown of electrical discharge, which will then be analyzed and processed. The study will provide best developments with regard to the application of ion implantation in various industrial sectors.

Evaluation of Fatigue Behavior and Surface Characteristics of Aluminum Alloy 2024 T6 After Electric Discharge Machining

NASA Astrophysics Data System (ADS)

Mehmood, Shahid; Shah, Masood; Pasha, Riffat Asim; Sultan, Amir

2017-10-01

The effect of electric discharge machining (EDM) on surface quality and consequently on the fatigue performance of Al 2024 T6 is investigated. Five levels of discharge current are analyzed, while all other electrical and nonelectrical parameters are kept constant. At each discharge current level, dog-bone specimens are machined by generating a peripheral notch at the center. The fatigue tests are performed on four-point rotating bending machine at room temperature. For comparison purposes, fatigue tests are also performed on the conventionally machined specimens. Linearized SN curves for 95% failure probability and with four different confidence levels (75, 90, 95 and 99%) are plotted for each discharge current level as well as for conventionally machined specimens. These plots show that the electric discharge machined (EDMed) specimens give inferior fatigue behavior as compared to conventionally machined specimen. Moreover, discharge current inversely affects the fatigue life, and this influence is highly pronounced at lower stresses. The EDMed surfaces are characterized by surface properties that could be responsible for change in fatigue life such as surface morphology, surface roughness, white layer thickness, microhardness and residual stresses. It is found that all these surface properties are affected by changing discharge current level. However, change in fatigue life by discharge current could not be associated independently to any single surface property.

Atmospheric-pressure electric discharge as an instrument of chemical activation of water solutions

NASA Astrophysics Data System (ADS)

Rybkin, V. V.; Shutov, D. A.

2017-11-01

Results of experimental studies and numerical simulations of physicochemical characteristics of plasmas generated in different types of atmospheric-pressure discharges (pulsed streamer corona, gliding electric arc, dielectric barrier discharge, glow-discharge electrolysis, diaphragmatic discharge, and dc glow discharge) used to initiate various chemical processes in water solutions are analyzed. Typical reactor designs are considered. Data on the power supply characteristics, plasma electron parameters, gas temperatures, and densities of active particles in different types of discharges excited in different gases and their dependences on the external parameters of discharges are presented. The chemical composition of active particles formed in water is described. Possible mechanisms of production and loss of plasma particles are discussed.

Laser-guided energetic discharges over large air gaps by electric-field enhanced plasma filaments

NASA Astrophysics Data System (ADS)

Théberge, Francis; Daigle, Jean-François; Kieffer, Jean-Claude; Vidal, François; Châteauneuf, Marc

2017-01-01

Recent works on plasma channels produced during the propagation of ultrashort and intense laser pulses in air demonstrated the guiding of electric discharges along the laser path. However, the short plasma lifetime limits the length of the laser-guided discharge. In this paper, the conductivity and lifetime of long plasma channels produced by ultrashort laser pulses is enhanced efficiently over many orders of magnitude by the electric field of a hybrid AC-DC high-voltage source. The AC electric pulse from a Tesla coil allowed to stimulate and maintain the highly conductive channel during few milliseconds in order to guide a subsequent 500 times more energetic discharge from a 30-kV DC source. This DC discharge was laser-guided over an air gap length of two metres, which is more than two orders of magnitude longer than the expected natural discharge length. Long plasma channel induced by laser pulses and stimulated by an external high-voltage source opens the way for wireless and efficient transportation of energetic current pulses over long air gaps and potentially for guiding lightning.

Laser-guided energetic discharges over large air gaps by electric-field enhanced plasma filaments

PubMed Central

Théberge, Francis; Daigle, Jean-François; Kieffer, Jean-Claude; Vidal, François; Châteauneuf , Marc

2017-01-01

Recent works on plasma channels produced during the propagation of ultrashort and intense laser pulses in air demonstrated the guiding of electric discharges along the laser path. However, the short plasma lifetime limits the length of the laser-guided discharge. In this paper, the conductivity and lifetime of long plasma channels produced by ultrashort laser pulses is enhanced efficiently over many orders of magnitude by the electric field of a hybrid AC-DC high-voltage source. The AC electric pulse from a Tesla coil allowed to stimulate and maintain the highly conductive channel during few milliseconds in order to guide a subsequent 500 times more energetic discharge from a 30-kV DC source. This DC discharge was laser-guided over an air gap length of two metres, which is more than two orders of magnitude longer than the expected natural discharge length. Long plasma channel induced by laser pulses and stimulated by an external high-voltage source opens the way for wireless and efficient transportation of energetic current pulses over long air gaps and potentially for guiding lightning. PMID:28053312

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

NASA Technical Reports Server (NTRS)

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.

Lightning Mapping Observations of Volume-Filling Small Discharges in Thunderstorms

NASA Astrophysics Data System (ADS)

Rison, W.; Krehbiel, P. R.; Thomas, R. J.; Rodeheffer, D.

2013-12-01

Lightning is usually considered to be a large-scale electrical discharge in the atmosphere. For example, the American Meteorological Society's Glossary of Meteorology defines lightning as "a transient, high-current electric discharge with pathlengths measured in kilometers" (http://glossary.ametsoc.org/wiki/Lightning). There have been several reported examples of short-duration discharges in thunderstorms, which have a duration of a few microseconds to less than a millisecond, and have a small spatial extent These short-duration discharges were located at high altitudes (> 14 km), altitudes consistent with being located between the upper positive charge and the negative screening layer. At these altitudes, the electric field needed to initiate an electrical discharge is much lower than it is at the altitudes of initiation for IC (~8 km) or CG (~5 km) flashes. We have recently reported on short-duration "precursor" discharges with durations of a few microseconds to a few milliseconds, which occur in the high-fields between the mid-level negative and upper positive charge regions. These "precursor" discharges are discrete in both time and space, being separated in time by hundreds of milliseconds to several seconds, and localized in space, usually very close to the initiation location of a subsequent IC discharge. We have recently observed nearly continuous, volume filling short-duration discharges in several thunderstorms. These discharges have durations of much less than a millisecond, spatial extents of less than a few hundred meters, and occur randomly in the volume between the mid-level negative and upper positive charge regions. During an active period, these discharges occur every few milliseconds. The rates of these discharges decreases dramatically to a few per second following an IC discharge, then increases to several hundred per second until the next discharge. In a storm just off the Florida coast, one cell was producing a large number of these small discharges, while a contemporaneous cell a few kilometers west produced no detectable small discharges. Short-duration discharges occur at altitudes between 10 km and 14 km in the intervals between lightning discharges. The rates of short-duration discharges decreases dramatically after a lightning discharge.

Minimizing radiation damage in nonlinear optical crystals

DOEpatents

Cooke, D.W.; Bennett, B.L.; Cockroft, N.J.

1998-09-08

Methods are disclosed for minimizing laser induced damage to nonlinear crystals, such as KTP crystals, involving various means for electrically grounding the crystals in order to diffuse electrical discharges within the crystals caused by the incident laser beam. In certain embodiments, electrically conductive material is deposited onto or into surfaces of the nonlinear crystals and the electrically conductive surfaces are connected to an electrical ground. To minimize electrical discharges on crystal surfaces that are not covered by the grounded electrically conductive material, a vacuum may be created around the nonlinear crystal. 5 figs.

Discharge processes and an electrical model of atmospheric pressure plasma jets in argon

NASA Astrophysics Data System (ADS)

Fang, Zhi; Shao, Tao; Yang, Jing; Zhang, Cheng

2016-01-01

In this paper, an atmospheric pressure plasma discharge in argon was generated using a needle-to-ring electrode configuration driven by a sinusoidal excitation voltage. The electric discharge processes and discharge characteristics were investigated by inspecting the voltage-current waveforms, Lissajous curves and lighting emission images. The change in discharge mode with applied voltage amplitude was studied and characterised, and three modes of corona discharge, dielectric barrier discharge (DBD) and jet discharge were identified, which appeared in turn with increasing applied voltage and can be distinguished clearly from the measured voltage-current waveforms, light-emission images and the changing gradient of discharge power with applied voltage. Based on the experimental results and discharge mechanism analysis, an equivalent electrical model and the corresponding equivalent circuit for characterising the whole discharge processes accurately was proposed, and the three discharge stages were characterised separately. A voltage-controlled current source (VCCS) associated with a resistance and a capacitance were used to represent the DBD stage, and the plasma plume and corona discharge were modelled by a variable capacitor in series with a variable resistor. Other factors that can influence the discharge, such as lead and stray capacitance values of the circuit, were also considered in the proposed model. Contribution to the Topical Issue "Recent Breakthroughs in Microplasma Science and Technology", edited by Kurt Becker, Jose Lopez, David Staack, Klaus-Dieter Weltmann and Wei Dong Zhu.

Electric-discharge-pumped nitrogen ion laser

NASA Technical Reports Server (NTRS)

Laudenslager, J. B.; Pacala, T. J.; Wittig, C.

1976-01-01

The routine operation is described of an N2(+) laser oscillating on the first negative band system of N2(+) which is produced in a preionized transverse discharge device. The discharge design incorporates features which favor the efficient production of the excitation transfer reaction of He2(+) with N2. A capacitive discharge switched by means of a high-current grounded grid thyratron is used to meet the design requirement of a volumetric discharge in high-pressure gas mixtures where the electric discharge need not have an ultrafast rise time (greater than 10 nsec) but should be capable of transferring large quantities of stored electric energy to the gas. A peak power of 180 kW in an 8-nsec laser pulse was obtained with a 0.1% mixture of N2 in helium at a total pressure of 3 atm. The most intense laser oscillations were observed on the (0,1) vibrational transition at 427.8 microns.

Electric field measurement in microwave discharge ion thruster with electro-optic probe.

PubMed

Ise, Toshiyuki; Tsukizaki, Ryudo; Togo, Hiroyoshi; Koizumi, Hiroyuki; Kuninaka, Hitoshi

2012-12-01

In order to understand the internal phenomena in a microwave discharge ion thruster, it is important to measure the distribution of the microwave electric field inside the discharge chamber, which is directly related to the plasma production. In this study, we proposed a novel method of measuring a microwave electric field with an electro-optic (EO) probe based on the Pockels effect. The probe, including a cooling system, contains no metal and can be accessed in the discharge chamber with less disruption to the microwave distribution. This method enables measurement of the electric field profile under ion beam acceleration. We first verified the measurement with the EO probe by a comparison with a finite-difference time domain numerical simulation of the microwave electric field in atmosphere. Second, we showed that the deviations of the reflected microwave power and the beam current were less than 8% due to inserting the EO probe into the ion thruster under ion beam acceleration. Finally, we successfully demonstrated the measurement of the electric-field profile in the ion thruster under ion beam acceleration. These measurements show that the electric field distribution in the thruster dramatically changes in the ion thruster under ion beam acceleration as the propellant mass flow rate increases. These results indicate that this new method using an EO probe can provide a useful guide for improving the propulsion of microwave discharge ion thrusters.

Electric Organ Discharges of Mormyrid Fish as a Possible Cue for Predatory Catfish

NASA Astrophysics Data System (ADS)

Hanika, S.; Kramer, B.

During reproductive migration the electroreceptive African sharptooth catfish, Clarias gariepinus (Siluriformes), preys mainly on a weakly electric fish, the bulldog Marcusenius macrolepidotus (Mormyridae; Merron 1993). This is puzzling because the electric organ discharges of known Marcusenius species are pulses of a duration (<1ms) too short for being detected by the catfishes' low-frequency electroreceptive system (optimum sensitivity, 10-30Hz Peters and Bretschneider 1981). On the recent discovery that M. macrolepidotus males emit discharges lasting approximately ten times longer than those of females (Kramer 1997a) we determined behavioral thresholds for discharges of both sexes, using synthetic playbacks of field-recorded discharges. C. gariepinus detected M. macrolepidotus male discharges down to a field gradient of 103μVpeak-peak/cm and up to a distance of 1.5m at natural field conditions. In contrast, thresholds for female discharges were not reached with our setup, and we presume the bulldogs eaten by catfish are predominantly male.

Experimental observation of the inductive electric field and related plasma nonuniformity in high frequency capacitive discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, S. K.; Chang, H. Y.

To elucidate plasma nonuniformity in high frequency capacitive discharges, Langmuir probe and B-dot probe measurements were carried out in the radial direction in a cylindrical capacitive discharge driven at 90 MHz with argon pressures of 50 and 400 mTorr. Through the measurements, a significant inductive electric field (i.e., time-varying magnetic field) was observed at the radial edge, and it was found that the inductive electric field creates strong plasma nonuniformity at high pressure operation. The plasma nonuniformity at high pressure operation is physically similar to the E-H mode transition typically observed in inductive discharges. This result agrees well with themore » theories of electromagnetic effects in large area and/or high frequency capacitive discharges.« less

Electric discharge during electrosurgery

PubMed Central

Shashurin, Alexey; Scott, David; Zhuang, Taisen; Canady, Jerome; Beilis, Isak I.; Keidar, Michael

2015-01-01

Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 103 A/cm2. The plasma electron density and electrical conductivities in the channel were found be 1016 cm−3 and (1-2) Ohm−1cm−1, respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold. PMID:25880721

Television image of a large upward electrical discharge above a thunderstorm system

NASA Technical Reports Server (NTRS)

Franz, R. C.; Nemzek, R. J.; Winckler, J. R.

1990-01-01

A low light-level TV camera is used to obtain an unusual image of luminous electrical discharge over a thunderstorm 250 km from the observation site. The image is presented and the discharge in the image is described. It is suggested that the image is probably due to two localized electric charge concentrations at the cloud tops. The hazard of these discharges for aircraft and rocket launches is examined. Consideration is given to the possibility that these discharges may account for unexplained photometric observations of distant lightning events that show a low rise rate of the luminous pulse and no electromagnetic sferic pulse like that in cloud-to-earth lightning strokes. The photometric events of this type that occurred on September 22-23, 1989 during hurricane Hugo are noted.

Electric discharge during electrosurgery.

PubMed

Shashurin, Alexey; Scott, David; Zhuang, Taisen; Canady, Jerome; Beilis, Isak I; Keidar, Michael

2015-04-16

Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 10(3) A/cm(2). The plasma electron density and electrical conductivities in the channel were found be 10(16) cm(-3) and (1-2) Ohm(-1) cm(-1), respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold.

Mechanism of the free charge carrier generation in the dielectric breakdown

NASA Astrophysics Data System (ADS)

Rahim, N. A. A.; Ranom, R.; Zainuddin, H.

2017-12-01

Many studies have been conducted to investigate the effect of environmental, mechanical and electrical stresses on insulator. However, studies on physical process of discharge phenomenon, leading to the breakdown of the insulator surface are lacking and difficult to comprehend. Therefore, this paper analysed charge carrier generation mechanism that can cause free charge carrier generation, leading toward surface discharge development. Besides, this paper developed a model of surface discharge based on the charge generation mechanism on the outdoor insulator. Nernst’s Planck theory was used in order to model the behaviour of the charge carriers while Poisson’s equation was used to determine the distribution of electric field on insulator surface. In the modelling of surface discharge on the outdoor insulator, electric field dependent molecular ionization was used as the charge generation mechanism. A mathematical model of the surface discharge was solved using method of line technique (MOL). The result from the mathematical model showed that the behaviour of net space charge density was correlated with the electric field distribution.

Television Image of a Large Upward Electrical Discharge Above a Thunderstorm System

NASA Astrophysics Data System (ADS)

Franz, R. C.; Nemzek, R. J.; Winckler, J. R.

1990-07-01

An image of an unusual luminous electrical discharge over a thunderstorm 250 kilometers from the observing site has been obtained with a low-light-level television camera. The discharge began at the cloud tops at 14 kilometers and extended into the clear air 20 kilometers higher. The image, which had a duration of less than 30 milliseconds, resembled two jets or fountains and was probably caused by two localized electric charge concentrations at the cloud tops. Large upward discharges may create a hazard for aircraft and rocket launches and, by penetrating into the ionosphere, may initiate whistler waves and other effects on a magnetospheric scale. Such upward electrical discharges may account for unexplained photometric observations of distant lightning events that showed a low rise rate of the luminous pulse and no electromagnetic sferic pulse of the type that accompanies cloud-to-earth lightning strokes. An unusually high rate of such photometric events was recorded during the night of 22 to 23 September 1989 during a storm associated with hurricane Hugo.

Television image of a large upward electrical discharge above a thunderstorm system.

PubMed

Franz, R C; Nemzek, R J; Winckler, J R

1990-07-06

An image of an unusual luminous electrical discharge over a thunderstorm 250 kilometers from the observing site has been obtained with a low-light-level television camera. The discharge began at the cloud tops at 14 kilometers and extended into the clear air 20 kilometers higher. The image, which had a duration of less than 30 milliseconds,resembled two jets or fountains and was probably caused by two localizd electric charge concentrations at the cloud tops. Large upward discharges may create a hazard for aircraft and rocket launches and, by penetrating into the ionosphere, may initiate whistler waves and other effects on a magnetospheric scale. Such upward electrical discharges may account for unexplained photometric observations of distant lightning events that showed a low rise rate of the luminous pulse and no electromagnetic sferic pulse of the type that accompanies cloud-to-earth lightning strokes. An unusually high rate of such photometric events was recorded during the night of 22 to 23 September 1989 during a storm associated with hurricane Hugo.

Timing Actions to Avoid Refractoriness: A Simple Solution for Streaming Sensory Signals

PubMed Central

Nogueira, Javier; Caputi, Ángel Ariel

2011-01-01

Segmenting self- from allo-generated signals is crucial for active sensory processing. We report a dynamic filter used by South American pulse electric fish to distinguish active electro-sensory signals carried by their own electric discharges from other concomitant electrical stimuli (i.e. communication signals). The filter has a sensory component, consisting of an onset type central electro-sensory neuron, and a motor component, consisting of a change in the fish's discharge rate when allo-generated electrical events occur in temporal proximity to the fish's own discharge. We investigated the sensory component of the filter by in vitro mimicking synaptic inputs occurring during behavioral responses to allo-generated interfering signals. We found that active control of the discharge enhances self-generated over allo-generated responses by forcing allo-generated signals into a central refractory period. This hypothesis was confirmed by field potential recordings in freely discharging fish. Similar sensory-motor mechanisms may also contribute to signal segmentation in other sensory systems. PMID:21789228

Water purification by electrical discharges

NASA Astrophysics Data System (ADS)

Arif Malik, Muhammad; Ghaffar, Abdul; Akbar Malik, Salman

2001-02-01

There is a continuing need for the development of effective, cheap and environmentally friendly processes for the disinfection and degradation of organic pollutants from water. Ozonation processes are now replacing conventional chlorination processes because ozone is a stronger oxidizing agent and a more effective disinfectant without any side effects. However, the fact that the cost of ozonation processes is higher than chlorination processes is their main disadvantage. In this paper recent developments targeted to make ozonation processes cheaper by improving the efficiency of ozone generation, for example, by incorporation of catalytic packing in the ozone generator, better dispersion of ozone in water and faster conversion of dissolved ozone to free radicals are described. The synthesis of ozone in electrical discharges is discussed. Furthermore, the generation and plasma chemical reactions of several chemically active species, such as H2O2, Obullet, OHbullet, HO2bullet, O3*, N2*, e-, O2-, O-, O2+, etc, which are produced in the electrical discharges are described. Most of these species are stronger oxidizers than ozone. Therefore, water treatment by direct electrical discharges may provide a means to utilize these species in addition to ozone. Much research and development activity has been devoted to achieve these targets in the recent past. An overview of these techniques and important developments that have taken place in this area are discussed. In particular, pulsed corona discharge, dielectric barrier discharge and contact glow discharge electrolysis techniques are being studied for the purpose of cleaning water. The units based on electrical discharges in water or close to the water level are being tested at industrial-scale water treatment plants.}

Response of lead-acid batteries to chopper-controlled discharge: Preliminary results

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1978-01-01

The preliminary results of simulated electric vehicle, chopper, speed controller discharge of a battery show energy output losses up to 25 percent compared to constant current discharges at the same average discharge current of 100 amperes. These energy losses are manifested as temperature rises during discharge, amounting to a two-fold increase for a 400-ampere pulse compared to the constant current case. Because of the potentially large energy inefficiency, the results suggest that electric vehicle battery/speed controller interaction must be carefully considered in vehicle design.

Response of lead-acid batteries to chopper-controlled discharge

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1978-01-01

The preliminary results of simulated electric vehicle, chopper, speed controller discharge of a battery show energy output losses at up to 25 percent compared to constant current discharges at the same average discharge current of 100 A. These energy losses are manifested as temperature rises during discharge, amounting to a two-fold increase for a 400-A pulse compared to the constant current case. Because of the potentially large energy inefficiency, the results suggest that electric vehicle battery/speed controller interaction must be carefully considered in vehicle design.

Grid regulation services for energy storage devices based on grid frequency

DOEpatents

Pratt, Richard M; Hammerstrom, Donald J; Kintner-Meyer, Michael C.W.; Tuffner, Francis K

2013-07-02

Disclosed herein are representative embodiments of methods, apparatus, and systems for charging and discharging an energy storage device connected to an electrical power distribution system. In one exemplary embodiment, a controller monitors electrical characteristics of an electrical power distribution system and provides an output to a bi-directional charger causing the charger to charge or discharge an energy storage device (e.g., a battery in a plug-in hybrid electric vehicle (PHEV)). The controller can help stabilize the electrical power distribution system by increasing the charging rate when there is excess power in the electrical power distribution system (e.g., when the frequency of an AC power grid exceeds an average value), or by discharging power from the energy storage device to stabilize the grid when there is a shortage of power in the electrical power distribution system (e.g., when the frequency of an AC power grid is below an average value).

Grid regulation services for energy storage devices based on grid frequency

DOEpatents

Pratt, Richard M.; Hammerstrom, Donald J.; Kintner-Meyer, Michael C. W.; Tuffner, Francis K.

2017-09-05

Disclosed herein are representative embodiments of methods, apparatus, and systems for charging and discharging an energy storage device connected to an electrical power distribution system. In one exemplary embodiment, a controller monitors electrical characteristics of an electrical power distribution system and provides an output to a bi-directional charger causing the charger to charge or discharge an energy storage device (e.g., a battery in a plug-in hybrid electric vehicle (PHEV)). The controller can help stabilize the electrical power distribution system by increasing the charging rate when there is excess power in the electrical power distribution system (e.g., when the frequency of an AC power grid exceeds an average value), or by discharging power from the energy storage device to stabilize the grid when there is a shortage of power in the electrical power distribution system (e.g., when the frequency of an AC power grid is below an average value).

Grid regulation services for energy storage devices based on grid frequency

DOEpatents

Pratt, Richard M; Hammerstrom, Donald J; Kintner-Meyer, Michael C.W.; Tuffner, Francis K

2014-04-15

Disclosed herein are representative embodiments of methods, apparatus, and systems for charging and discharging an energy storage device connected to an electrical power distribution system. In one exemplary embodiment, a controller monitors electrical characteristics of an electrical power distribution system and provides an output to a bi-directional charger causing the charger to charge or discharge an energy storage device (e.g., a battery in a plug-in hybrid electric vehicle (PHEV)). The controller can help stabilize the electrical power distribution system by increasing the charging rate when there is excess power in the electrical power distribution system (e.g., when the frequency of an AC power grid exceeds an average value), or by discharging power from the energy storage device to stabilize the grid when there is a shortage of power in the electrical power distribution system (e.g., when the frequency of an AC power grid is below an average value).

Environmental and human impact on the sedimentary dynamic in the Rhone Delta subaquatic canyons (France-Switzerland)

NASA Astrophysics Data System (ADS)

Arantegui, A.; Corella, J. P.; Loizeau, J. L.; Anselmetti, F. S.; Girardclos, S.

2012-04-01

Deltas are very sensitive environments and highly vulnerable to variations in water discharge and the amount of suspended sediment load provided by the delta-forming currents. Human activities in the watershed, such as building of dams and irrigation ditches, or river bed deviations, may affect the discharge regime and sediment input, thus affecting delta growth. Underwater currents create deeply incised canyons cutting into the delta lobes. Understanding the sedimentary processes in these subaquatic canyons is crucial to reconstruct the fluvial evolution and human impact on deltaic environments and to carry out a geological risk assessment related to mass movements, which may affect underwater structures and civil infractructure. Recently acquired high-resolution multibeam bathymetry on the Rhone Delta in Lake Geneva (Sastre et al. 2010) revealed the complexity of the underwater morphology formed by active and inactive canyons first described by Forel (1892). In order to unravel the sedimentary processes and sedimentary evolution in these canyons, 27 sediment cores were retrieved in the distal part of each canyon and in the canyon floor/levee complex of the active canyon. Geophysical, sedimentological, geochemical and radiometric dating techniques were applied to analyse these cores. Preliminary data show that only the canyon originating at the current river mouth is active nowadays, while the others remain inactive since engineering works in the watershed occurred, confirming Sastre et al. (2010). However, alternating hemipelagic and turbiditic deposits on the easternmost canyons, evidence underflow processes during the last decades as well. Two canyons, which are located close to the Rhone river mouth, correspond to particularly interesting deeply incised crevasse channels formed when the underwater current broke through the outer bend of a meander in the proximal northern levee. In these canyons, turbidites occur in the sediment record indicating ongoing sediment dynamics during whether extreme flood events or mass-movements due to deltaic scarp failures. The active canyon shows a classic turbiditic system with frequent spillover processes in the canyon floor/levee complex. Geotechnical measurements, a decrease in the frequency of turbidites and a fining upward sequence along the levee suggest that erosion dominates sedimentation in the canyon floor, while sedimentation dominates in the rapid levee building-up process, with sedimentation rates that exceed 3cm/yr in the proximal areas. Therefore, mechanisms controlling the sedimentary evolution on the active canyon result in a complex interplay between erosion and sedimentation. Further research will provide a detailed evaluation of the human impact on sedimentary dynamic in the Rhone Delta subaquatic canyons.

Inactivation of Escherichia coli and Staphylococcus aureus on contaminated perilla leaves by Dielectric Barrier Discharge (DBD) plasma treatment.

PubMed

Ji, Sang Hye; Ki, Se Hoon; Ahn, Ji Ho; Shin, Jae Ho; Hong, Eun Jeong; Kim, Yun Ji; Choi, Eun Ha

2018-04-02

This study focused on sterilization methods for the reduction of microorganisms on perilla leaves by cylinder type Dielectric Barrier Discharge (DBD) plasma with underwater bubbler treatment. S. aureus and E. coli in a suspension were reduced to less than 3.4 and 0.5 log CFU/ml after the plasma treatment for 3 min, respectively. On the perilla leaves, they were also reduced to 4.8 and 1.6 log CFU/ml after the plasma treatment, respectively. The S. aureus and E. coli bacterial cell wall was damaged by the plasma treatment evident by scanning electron microscopic analysis. The observed infrared bands of the FTIR spectra demonstrated changes in protein, lipid, polysaccharide, polyphosphate group and other carbohydrate functionalities of plasma treated bacteria and untreated bacterial cell membranes. The degradation of the constituent bonds of the bacterial cell membrane by RONS generated from plasma destroys the DNA, RNA, and proteins within the cell, and may eventually cause cell death. In this study, H 2 O 2 (13.68 μM) and NO 3 (138 μM), which are the main factors generated by plasma, proved to have a bactericidal effect by inducing lipid peroxidation of bacterial cell membranes. In conclusion, cylinder type DBD plasma with underwater bubbler can be used as an environmentally friendly food disinfection device in cleaning processes of the food industry. Copyright © 2018 Elsevier Inc. All rights reserved.

Metod And Apparatus For Debris Mitigation For An Electrical Discharge Source

DOEpatents

Klebanoff, Leonard E.; Silfvast, William T.; Rader, Daniel J.

2005-05-03

Method and apparatus for mitigating the transport of debris generated and dispersed from electric discharge sources by thermophoretic and electrostatic deposition. A member is positioned adjacent the front electrode of an electric discharge source and used to establish a temperature difference between it and the front electrode. By flowing a gas between the member and the front electrode a temperature gradient is established that can be used for thermophoretic deposition of particulate debris on either the member or front electrode depending upon the direction of the thermal gradient. Establishing an electric field between the member and front electrode can aid in particle deposition by electrostatic deposition.

Method and apparatus for debris mitigation for an electrical discharge source

DOEpatents

Klebanoff, Leonard E [San Clemente, CA; Rader, Daniel J [Albuquerque, NM; Silfvast, William T [Helena, CA

2006-01-24

Method and apparatus for mitigating the transport of debris generated and dispersed from electric discharge sources by thermophoretic and electrostatic deposition. A member is positioned adjacent the front electrode of an electric discharge source and used to establish a temperature difference between it and the front electrode. By flowing a gas between the member and the front electrode a temperature gradient is established that can be used for thermophoretic deposition of particulate debris on either the member or front electrode depending upon the direction of the thermal gradient. Establishing an electric field between the member and front electrode can aid in particle deposition by electrostatic deposition.

Physically Damped Noise Canceling Hydrophone

DTIC Science & Technology

2016-06-24

Description of the Prior Art [0004] An acoustic hydrophone can transfer underwater pressure waves to electrical energy. As a result, an output charge...includes two types of piezoelectric transducers coupled together. One transducer maintains voids and is sensitive to hydrostatic acoustic signals. The...the cable assembly. [0009] Cray (United States Patent No. 6,370,084) discloses an acoustic vector sensor. An accelerometer of the acoustic vector

46 CFR 108.437 - Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Pipe sizes and discharge rates for enclosed ventilation... Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.437 Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment. (a) The minimum pipe size for the initial...

46 CFR 108.437 - Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment. 108.437 Section 108.437 Shipping COAST GUARD, DEPARTMENT OF... Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.437 Pipe sizes and discharge rates for...

Plasma discharge self-cleaning filtration system

DOEpatents

Cho, Young I.; Fridman, Alexander; Gutsol, Alexander F.; Yang, Yong

2014-07-22

The present invention is directed to a novel method for cleaning a filter surface using a plasma discharge self-cleaning filtration system. The method involves utilizing plasma discharges to induce short electric pulses of nanoseconds duration at high voltages. These electrical pulses generate strong Shockwaves that disintegrate and dislodge particulate matter located on the surface of the filter.

Generation of ultra-fast cumulative water jets by sub-microsecond underwater electrical explosion of conical wire arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shafer, D.; Gurovich, V. Tz.; Gleizer, S.

The results of experiments with underwater electrical explosion of modified conical arrays of copper and aluminum wires are presented. A pulsed generator producing a 550 kA-amplitude current with a 400 ns rise time was used in the explosion of the arrays. The array explosion generates water flows converging at the axis of the cone. This flow generates a fast-moving water jet with a velocity exceeding 1.8 × 10{sup 5 }cm/s, which was observed being ejected from the surface of the water covering the array. The positions of the water jet were measured by multiple-exposure fast framing imaging. In experiments, the apex angle of the array,more » the thickness of the water layer above the arrays, or the material of the wires was altered, which changed the resulting velocities and shapes of the emitted jets. A model that considers the converging stationary flow of a slightly compressible fluid is suggested. The velocities and shapes of the jets obtained by this model agree well with the experimentally measured jet velocities.« less

The shocking predatory strike of the electric eel.

PubMed

Catania, Kenneth

2014-12-05

Electric eels can incapacitate prey with an electric discharge, but the mechanism of the eel's attack is unknown. Through a series of experiments, I show that eel high-voltage discharges can activate prey motor neurons, and hence muscles, allowing eels to remotely control their target. Eels prevent escape in free-swimming prey using high-frequency volleys to induce immobilizing whole-body muscle contraction (tetanus). Further, when prey are hidden, eels can emit periodic volleys of two or three discharges that cause massive involuntary twitch, revealing the prey's location and eliciting the full, tetanus-inducing volley. The temporal patterns of eel electrical discharges resemble motor neuron activity that induces fast muscle contraction, suggesting that eel high-voltage volleys have been selected to most efficiently induce involuntary muscle contraction in nearby animals. Copyright © 2014, American Association for the Advancement of Science.

Social interactions between live and artificial weakly electric fish: Electrocommunication and locomotor behavior of Mormyrus rume proboscirostris towards a mobile dummy fish

PubMed Central

Kirschbaum, Frank; von der Emde, Gerhard

2017-01-01

Mormyrid weakly electric fish produce short, pulse-type electric organ discharges for actively probing their environment and to communicate with conspecifics. Animals emit sequences of pulse-trains that vary in overall frequency and temporal patterning and can lead to time-locked interactions with the discharge activity of other individuals. Both active electrolocation and electrocommunication are additionally accompanied by stereotypical locomotor patterns. However, the concrete roles of electrical and locomotor patterns during social interactions in mormyrids are not well understood. Here we used a mobile fish dummy that was emitting different types of electrical playback sequences to study following behavior and interaction patterns (electrical and locomotor) between individuals of weakly electric fish. We confronted single individuals of Mormyrus rume proboscirostris with a mobile dummy fish designed to attract fish from a shelter and recruit them into an open area by emitting electrical playbacks of natural discharge sequences. We found that fish were reliably recruited by the mobile dummy if it emitted electrical signals and followed it largely independently of the presented playback patterns. While following the dummy, fish interacted with it spatially by displaying stereotypical motor patterns, as well as electrically, e.g. through discharge regularizations and by synchronizing their own discharge activity to the playback. However, the overall emission frequencies of the dummy were not adopted by the following fish. Instead, social signals based on different temporal patterns were emitted depending on the type of playback. In particular, double pulses were displayed in response to electrical signaling of the dummy and their expression was positively correlated with an animals' rank in the dominance hierarchy. Based on additional analysis of swimming trajectories and stereotypical locomotor behavior patterns, we conclude that the reception and emission of electrical communication signals play a crucial role in mediating social interactions in mormyrid weakly electric fish. PMID:28902915

DUMAND-II (deep underwater muon and neutrino detector) progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, K.K.; The DUMAND Collaboration

1995-07-10

The DUMAND II detector will search for astronomical sources of high energy neutrinos. Successful deployment of the basic infrastructure, including the shore cable, the underwater junction box, and an environmental module was accomplished in December, 1993. One optical module string was also deployed and operated, logging data for about 10 hours. The underwater cable was connected to the shore station where we were able to successfully exercise system controls and log further environmental data. After this time, water leaking into the electronics control module for the deployed string disabled the string electrical system. The acquired data are consistent with themore » expected rate of downgoing muons, and our ability to reconstruct muons was demonstrated. The measured acoustical backgrounds are consistent with expectation, which should allow acoustical detection of nearby PeV particle cascades. The disabled string has been recovered and is undergoing repairs ashore. We have identified the source of the water leak and implemented additional testing and QC procedures to ensure no repetition in our next deployment. We will be ready to deploy three strings and begin continuous data taking in late 1994 or early 1995. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.« less

Surface Tension Mediated Under-Water Adhesion of Rigid Spheres on Soft, Charged Surfaces

NASA Astrophysics Data System (ADS)

Sinha, Shayandev; Das, Siddhartha

2015-11-01

Understanding the phenomenon of surface-tension-mediated under-water adhesion is necessary for studying a plethora of physiological and technical phenomena, such as the uptake of bacteria or nanoparticle by cells, attachment of virus on bacterial surfaces, biofouling on large ocean vessels and marine devices, etc. This adhesion phenomenon becomes highly non-trivial in case the soft surface where the adhesion occurs is also charged. Here we propose a theory for analyzing such an under-water adhesion of a rigid sphere on a soft, charged surface, represented by a grafted polyelectrolyte layer (PEL). We develop a model based on the minimization of free energy that, in addition to considering the elastic and the surface-tension-mediated adhesion energies, also accounts for the PEL electric double layer (EDL) induced electrostatic energies. We show that in the presence of surface charges, adhesion gets enhanced. This can be explained by the fact that the increase in the elastic energy is better balanced by the lowering of the EDL energy associated with the adhesion process. The entire behaviour is further dictated by the surface tension components that govern the adhesion energy.

Electric field strength determination in filamentary DBDs by CARS-based four-wave mixing

NASA Astrophysics Data System (ADS)

Boehm, Patrick; Kettlitz, Manfred; Brandenburg, Ronny; Hoeft, Hans; Czarnetzki, Uwe

2016-09-01

The electric field strength is a basic parameter of non-thermal plasmas. Therefore, a profound knowledge of the electric field distribution is crucial. In this contribution a four wave mixing technique based on Coherent Anti-Stokes Raman spectroscopy (CARS) is used to measure electric field strengths in filamentary dielectric barrier discharges (DBDs). The discharges are operated with a pulsed voltage in nitrogen at atmospheric pressure. Small amounts hydrogen (10 vol%) are admixed as tracer gas to evaluate the electric field strength in the 1 mm discharge gap. Absolute values of the electric field strength are determined by calibration of the CARS setup with high voltage amplitudes below the ignition threshold of the arrangement. Alteration of the electric field strength has been observed during the internal polarity reversal and the breakdown process. In this case the major advantage over emission based methods is that this technique can be used independently from emission, e.g. in the pre-phase and in between two consecutive, opposite discharge pulses where no emission occurs at all. This work was supported by the Deutsche Forschungsgemeinschaft, Forschergruppe FOR 1123 and Sonderforschungsbereich TRR 24 ``Fundamentals of complex plasmas''.

Mechanism of singlet oxygen deactivation in an electric discharge oxygen – iodine laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azyazov, V N; Mikheyev, P A; Torbin, A P

2014-12-31

We have determined the influence of the reaction of molecular singlet oxygen with a vibrationally excited ozone molecule O{sub 2}(a {sup 1}Δ) + O{sub 3}(ν) → 2O{sub 2} + O on the removal rate of O{sub 2}(a {sup 1}Δ) in an electric-discharge-driven oxygen – iodine laser. This reaction has been shown to be a major channel of O{sub 2}(a {sup 1}Δ) loss at the output of an electric-discharge singlet oxygen generator. In addition, it can also contribute significantly to the loss of O{sub 2}(a {sup 1}Δ) in the discharge region of the generator. (lasers)

Partial discharge characteristics of polymer nanocomposite materials in electrical insulation: a review of sample preparation techniques, analysis methods, potential applications, and future trends.

PubMed

Izzati, Wan Akmal; Arief, Yanuar Z; Adzis, Zuraimy; Shafanizam, Mohd

2014-01-01

Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends.

46 CFR 169.692 - Remote stop stations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Machinery and Electrical Electrical Installations on Vessels of 100 Gross Tons and Over § 169.692 Remote... propulsion unit, (b) A bilge slop or dirty oil discharge shutdown at the deck discharge, (c) A ventilation...

Digital sonar system

DOEpatents

Young, K.K.; Wilkes, R.J.

1995-11-21

A transponder of an active digital sonar system identifies a multifrequency underwater activating sonar signal received from a remote sonar transmitter. The transponder includes a transducer that receives acoustic waves, including the activating sonar signal, and generates an analog electrical receipt signal. The analog electrical receipt signal is converted to a digital receipt signal and cross-correlated with a digital transmission signal pattern corresponding to the activating sonar signal. A relative peak in the cross-correlation value is indicative of the activating sonar signal having been received by the transponder. In response to identifying the activating sonar signal, the transponder transmits a responding multifrequency sonar signal. 4 figs.

Digital sonar system

DOEpatents

Young, Kenneth K.; Wilkes, R. Jeffrey

1995-01-01

A transponder of an active digital sonar system identifies a multifrequency underwater activating sonar signal received from a remote sonar transmitter. The transponder includes a transducer that receives acoustic waves, including the activating sonar signal, and generates an analog electrical receipt signal. The analog electrical receipt signal is converted to a digital receipt signal and cross-correlated with a digital transmission signal pattern corresponding to the activating sonar signal. A relative peak in the cross-correlation value is indicative of the activating sonar signal having been received by the transponder. In response to identifying the activating sonar signal, the transponder transmits a responding multifrequency sonar signal.

Transverse-type laser assembly using induced electrical discharge excitation and method

DOEpatents

Ault, Earl R.

1994-01-01

A transverse-type laser assembly is disclosed herein. This assembly defines a laser cavity containing a vapor or gaseous substance which lases when subjected to specific electrical discharge excitation between a pair of spaced-apart electrodes located within the cavity in order to produce a source of light. An arrangement located entirely outside the laser cavity is provided for inducing a voltage across the electrodes within the cavity sufficient to provide the necessary electrical discharge excitation to cause a vapor substance between the electrodes to lase.

Transverse-type laser assembly using induced electrical discharge excitation and method

DOEpatents

Ault, E.R.

1994-04-19

A transverse-type laser assembly is disclosed herein. This assembly defines a laser cavity containing a vapor or gaseous substance which lases when subjected to specific electrical discharge excitation between a pair of spaced-apart electrodes located within the cavity in order to produce a source of light. An arrangement located entirely outside the laser cavity is provided for inducing a voltage across the electrodes within the cavity sufficient to provide the necessary electrical discharge excitation to cause a vapor substance between the electrodes to lase. 3 figures.

Treatment of Dyeing Wastewater by Using Positive Pulsed Corona Discharge to Water Surface

NASA Astrophysics Data System (ADS)

Young, Sun Mok; Hyun, Tae Ahn; Joeng, Tai Kim

2007-02-01

This study investigated the treatment of textile-dyeing wastewater by using an electrical discharge technique (positive pulsed corona discharge). The high-voltage electrode was placed above the surface of the wastewater while the ground electrode was submerged in the wastewater. The electrical discharge starting at the tip of the high voltage electrode propagated toward the surface of the wastewater, producing various oxidative radicals and ozone. Oxygen was used as the working gas instead of air to prevent nitrogen oxides from forming. The simulated wastewater was made up with amaranth, which is a kind of azo dye. The results obtained showed that the chromaticity of the wastewater was almost completely removed within an hour. The ultraviolet/visible spectra of the wastewater treated by the electrical discharge revealed that the total hydrocarbon level also decreased significantly.

Pulsed high voltage electric discharge disinfection of microbially contaminated liquids.

PubMed

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.

A pulser-sustainer carbon monoxide electric-discharge supersonic laser

NASA Technical Reports Server (NTRS)

Monson, D. J.; Srinivasan, G.

1977-01-01

Operation of a CW CO electric-discharge supersonic laser with a pulser-sustainer discharge is described. High-power operation as well as independent control over electron energy and density are demonstrated. Maximum input power achieved to date is 100 kW. The maximum output power is 6 kW or 10% of the sustainer positive-column power. Much improved performance appears possible.

Effects on Freshwater Organisms of Magnetic Fields Associated with Hydrokinetic Turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cada, Glenn F; Bevelhimer, Mark S; Riemer, Kristina P

2011-07-01

Underwater cables will be used to transmit electricity between turbines in an array (interturbine cables), between the array and a submerged step-up transformer (if part of the design), and from the transformer or array to shore. All types of electrical transmitting cables (as well as the generator itself) will emit EMF into the surrounding water. The electric current will induce magnetic fields in the immediate vicinity, which may affect the behavior or viability of animals. Because direct electrical field emissions can be prevented by shielding and armoring, we focused our studies on the magnetic fields that are unavoidably induced bymore » electric current moving through a generator or transmission cable. These initial experiments were carried out to evaluate whether a static magnetic field, such as would be produced by a direct current (DC) transmitting cable, would affect the behavior of common freshwater fish and invertebrates.« less

Goodenough Spring, Texas, USA: Discharge and water chemistry of a large spring deeply submerged under the binational Amistad Reservoir

NASA Astrophysics Data System (ADS)

Kamps, Ray H.; Tatum, Gregg S.; Gault, Mike; Groeger, Alan W.

2009-06-01

Goodenough Spring (Texas, USA) is a large spring near the border of the American state of Texas and the Mexican state of Coahuila, discharging into the international Amistad Reservoir on the river Rio Grande (Rio Bravo). Discharge was routinely measured from 1928 until 1968 to partition the flow of the river between the two countries in accordance with water-use treaties. Samples were analyzed for water-quality parameters in 1967-1968 prior to inundation under 45 m of Amistad Reservoir in 1968. Subsequently, discharge has been estimated indirectly by the International Boundary and Water Commission (IBWC). For the first direct measurements of the spring in 37 years, velocity and cross-sectional measurements were made and water samples collected in the summer of 2005 using advanced self-contained underwater breathing apparatus (SCUBA) techniques. Spring discharge was calculated at 2.03 m3 s-1, approximately one-half of the historical mean of 3.94 m3 s-1. In situ and laboratory analyses of samples for temperature, pH, dissolved oxygen, specific conductance, alkalinity, nitrate-nitrogen, dissolved solids, chloride, sulfate, fluoride, phosphorus, calcium, sodium, potassium, magnesium, and iron showed the water quality to be very good for human consumption and crop irrigation. Measurement values are relatively unchanged from those reported 37 years prior.

The Effects of Self-Discharge on the Performance of Symmetric Electric Double-Layer Capacitors and Active Electrolyte-Enhanced Supercapacitors: Insights from Modeling and Simulation

NASA Astrophysics Data System (ADS)

Ike, Innocent S.; Sigalas, Iakovos; Iyuke, Sunny E.

2017-02-01

The effects of self-discharge on the performance of symmetric electric double-layer capacitors (EDLCs) and active electrolyte-enhanced supercapacitors were examined by incorporating self-discharge into electrochemical capacitor models during charging and discharging. The sources of self-discharge in capacitors were side reactions or redox reactions and several impurities and electric double-layer (EDL) instability. The effects of self-discharge during capacitor storage was negligible since it took a fully charged capacitor a minimum of 14.0 days to be entirely discharged by self-discharge in all conditions studied, hence self-discharge in storage condition can be ignored. The first and second charge-discharge cycle energy efficiencies η_{{{{E}}1}} and η_{{{{E}}2}} of a capacitor of electrode effective conductivity α1 = 0.05 S/cm with only EDL instability self-discharge with current density J_{{VR}} = 1.25 × 10-3 A/cm2 were 72.33% and 72.34%, respectively. Also, energy efficiencies η_{{{{E}}1}} and η_{{{{E}}2}} of a similar capacitor with both side reactions and redox reactions and EDL instability self-discharges with current densities J_{{VR}} = 0.00125 A/cm2 and J_{{{{VR}}1}} = 0.0032 A/cm2 were 38.13% and 38.14% respectively, compared with 84.24% and 84.25% in a similar capacitor without self-discharge. A capacitor with only EDL instability self-discharge and that with both side reactions and redox reactions and EDL instability self-discharge lost 9.73 Wh and 28.38 Wh of energy, respectively, through self-discharge during charging and discharging. Hence, EDLCs charging and discharging time is significantly dependent on the self-discharge rate which are too large to be ignored.

Laboratory simulation of irradiation-induced dielectric breakdown in spacecraft charging

NASA Technical Reports Server (NTRS)

Yadlowsky, E. J.; Churchill, R. J.; Hazelton, R. C.

1980-01-01

The discharging of dielectric samples irradiated by a beam of monoenergetic electrons is investigated. The development of a model, or models, which describe the discharge phenomena occuring on the irradiated dielectric targets is discussed. The electrical discharge characteristics of irradiated dielectric samples are discussed and the electrical discharge paths along dielectric surfaces and within the dielectric material are determined. The origin and destination of the surface emitted particles is examined and the charge and energy balance in the system is evaluated.

Branching Patterns and Stepped Leaders in an Electric-Circuit Model for Creeping Discharge

NASA Astrophysics Data System (ADS)

Hidetsugu Sakaguchi,; Sahim M. Kourkouss,

2010-06-01

We construct a two-dimensional electric circuit model for creeping discharge. Two types of discharge, surface corona and surface leader, are modeled by a two-step function of conductance. Branched patterns of surface leaders surrounded by the surface corona appear in numerical simulation. The fractal dimension of branched discharge patterns is calculated by changing voltage and capacitance. We find that surface leaders often grow stepwise in time, as is observed in lightning leaders of thunder.

NPDES Permit for Potomac Electric Power Company (PEPCO) Benning Generating Station

EPA Pesticide Factsheets

Under National Pollutant Discharge Elimination System permit number DC0000094, the Potomac Electric Power Company (PEPCO) Benning Generating Station is authorized to discharge from from a facility to receiving waters named Anacostia River.

Mathematical model of optical signals emitted by electrical discharges occuring in electroinsulating oil

NASA Astrophysics Data System (ADS)

Kozioł, Michał

2017-10-01

The article presents a parametric model describing the registered distributions spectrum of optical radiation emitted by electrical discharges generated in the systems: the needle- needle, the needleplate and in the system for surface discharges. Generation of electrical discharges and registration of the emitted radiation was carried out in three different electrical insulating oils: fabric new, operated (used) and operated with air bubbles. For registration of optical spectra in the range of ultraviolet, visible and near infrared a high resolution spectrophotometer was. The proposed mathematical model was developed in a regression procedure using gauss-sigmoid type function. The dependent variable was the intensity of the recorded optical signals. In order to estimate the optimal parameters of the model an evolutionary algorithm was used. The optimization procedure was performed in Matlab environment. For determination of the matching quality of theoretical parameters of the regression function to the empirical data determination coefficient R2 was applied.

Micro electrical discharge milling using deionized water as a dielectric fluid

NASA Astrophysics Data System (ADS)

Chung, Do Kwan; Kim, Bo Hyun; Chu, Chong Nam

2007-05-01

In electrical discharge machining, dielectric fluid is an important factor affecting machining characteristics. Generally, kerosene and deionized water have been used as dielectric fluids. In micro electrical discharge milling, which uses a micro electrode as a tool, the wear of the tool electrode decreases the machining accuracy. However, the use of deionized water instead of kerosene can reduce the tool wear and increase the machining speed. This paper investigates micro electrical discharge milling using deionized water. Deionized water with high resistivity was used to minimize the machining gap. Machining characteristics such as the tool wear, machining gap and machining rate were investigated according to resistivity of deionized water. As the resistivity of deionized water decreased, the tool wear was reduced, but the machining gap increased due to electrochemical dissolution. Micro hemispheres were machined for the purpose of investigating machining efficiency between dielectric fluids, kerosene and deionized water.

Electric charging/discharging characteristics of super capacitor, using de-alloying and anodic oxidized Ti-Ni-Si amorphous alloy ribbons.

PubMed

Fukuhara, Mikio; Sugawara, Kazuyuki

2014-01-01

Charging/discharging behaviors of de-alloyed and anodic oxidized Ti-Ni-Si amorphous alloy ribbons were measured as a function of current between 10 pA and 100 mA, using galvanostatic charge/discharging method. In sharp contrast to conventional electric double layer capacitor (EDLC), discharging behaviors for voltage under constant currents of 1, 10 and 100 mA after 1.8 ks charging at 100 mA show parabolic decrease, demonstrating direct electric storage without solvents. The supercapacitors, devices that store electric charge on their amorphous TiO2-x surfaces that contain many 70-nm sized cavities, show the Ragone plot which locates at lower energy density region near the 2nd cells, and RC constant of 800 s (at 1 mHz), which is 157,000 times larger than that (5 ms) in EDLC.

Electric charging/discharging characteristics of super capacitor, using de-alloying and anodic oxidized Ti-Ni-Si amorphous alloy ribbons

PubMed Central

2014-01-01

Charging/discharging behaviors of de-alloyed and anodic oxidized Ti-Ni-Si amorphous alloy ribbons were measured as a function of current between 10 pA and 100 mA, using galvanostatic charge/discharging method. In sharp contrast to conventional electric double layer capacitor (EDLC), discharging behaviors for voltage under constant currents of 1, 10 and 100 mA after 1.8 ks charging at 100 mA show parabolic decrease, demonstrating direct electric storage without solvents. The supercapacitors, devices that store electric charge on their amorphous TiO2-x surfaces that contain many 70-nm sized cavities, show the Ragone plot which locates at lower energy density region near the 2nd cells, and RC constant of 800 s (at 1 mHz), which is 157,000 times larger than that (5 ms) in EDLC. PMID:24959106

Distribution of E/N and N/e/ in a cross-flow electric discharge laser. [electric field to neutral gas density and electron number density

NASA Technical Reports Server (NTRS)

Dunning, J. W., Jr.; Lancashire, R. B.; Manista, E. J.

1976-01-01

Measurements have been conducted of the effect of the convection of ions and electrons on the discharge characteristics in a large scale laser. The results are presented for one particular distribution of ballast resistance. Values of electric field, current density, input power density, ratio of electric field to neutral gas density (E/N), and electron number density were calculated on the basis of measurements of the discharge properties. In a number of graphs, the E/N ratio, current density, power density, and electron density are plotted as a function of row number (downstream position) with total discharge current and gas velocity as parameters. From the dependence of the current distribution on the total current, it appears that the electron production in the first two rows significantly affects the current flowing in the succeeding rows.

Electric field in a plasma channel in a high-pressure nanosecond discharge in hydrogen: a coherent anti-stokes Raman scattering study.

PubMed

Yatom, S; Tskhai, S; Krasik, Ya E

2013-12-20

Experimental results of a study of the electric field in a plasma channel produced during nanosecond discharge at a H2 gas pressure of (2-3)×10(5)  Pa by the coherent anti-Stokes scattering method are reported. The discharge was ignited by applying a voltage pulse with an amplitude of ∼100  kV and a duration of ∼5  ns to a blade cathode placed at a distance of 10 and 20 mm from the anode. It was shown that this type of gas discharge is characterized by the presence of an electric field in the plasma channel with root-mean-square intensities of up to 30  kV/cm. Using polarization measurements, it was found that the direction of the electric field is along the cathode-anode axis.

Electrical model of dielectric barrier discharge homogenous and filamentary modes

NASA Astrophysics Data System (ADS)

López-Fernandez, J. A.; Peña-Eguiluz, R.; López-Callejas, R.; Mercado-Cabrera, A.; Valencia-Alvarado, R.; Muñoz-Castro, A.; Rodríguez-Méndez, B. G.

2017-01-01

This work proposes an electrical model that combines homogeneous and filamentary modes of an atmospheric pressure dielectric barrier discharge cell. A voltage controlled electric current source has been utilized to implement the power law equation that represents the homogeneous discharge mode, which starts when the gas breakdown voltage is reached. The filamentary mode implies the emergence of electric current conducting channels (microdischarges), to add this phenomenon an RC circuit commutated by an ideal switch has been proposed. The switch activation occurs at a higher voltage level than the gas breakdown voltage because it is necessary to impose a huge electric field that contributes to the appearance of streamers. The model allows the estimation of several electric parameters inside the reactor that cannot be measured. Also, it is possible to appreciate the modes of the DBD depending on the applied voltage magnitude. Finally, it has been recognized a good agreement between simulation outcomes and experimental results.

Glow-to-arc transition in plasma-assisted combustion at 100 MPa

NASA Astrophysics Data System (ADS)

Larsson, A.; Andreasson, S.

2015-04-01

Electric energy can be added to the combustion of solid propellants in a gun in order to augment and to control parts of the internal ballistic cycle of the launch of a projectile. The pressure in the chamber and bore during launch is typically several hundred megapascal and the electric energy must be delivered to the flame at such a pressure level. To increase the understanding of the interaction between a flame and an electrical discharge at elevated pressure, experiments have been performed at 100 MPa in a combustion chamber where electric current has been conducted through the flame of a solid propellant. Pressure, voltage and current have been measured. The measured signals have been analysed and interpreted. The sequence of events has been interpreted as an initial formation of a glow-like discharge in the flame followed by a discharge mode transition to a filamentary arc discharge. The transition is shown to be dependent on the flame conductivity. For the test propellant used (Nzk5230 doped with 5% potassium nitrate), the flame conductivity is calculated to be 0.84 S m-1 and the discharge mode transition is found to occur after a dissipation of 0.2-0.4 kJ, or 11-22 kJ m-1 of electric energy, at an electric power of 0.1-0.5 MW.

Upward electrical discharges observed above Tropical Depression Dorian

PubMed Central

Liu, Ningyu; Spiva, Nicholas; Dwyer, Joseph R.; Rassoul, Hamid K.; Free, Dwayne; Cummer, Steven A.

2015-01-01

Observation of upward electrical discharges from thunderstorms has been sporadically reported in the scientific literature. According to their terminal altitudes, they are classified as starters (20–30 km), jets (40–50 km) and gigantic jets (70–90 km). They not only have a significant impact on the occupied atmospheric volumes but also electrically couple different atmospheric regions. However, as they are rare and unpredictable, our knowledge of them has been built on observations that typically record only one type of such discharges. Here we report a close-distance observation of seven upward discharges including one starter, two jets and four gigantic jets above Tropical Depression Dorian. Our optical and electromagnetic data indicate that all events are of negative polarity, suggesting they are initiated in the same thundercloud charge region. The data also indicate that the lightning-like discharge channel can extend above thunderclouds by about 30 km, but the discharge does not emit low-frequency electromagnetic radiation as normal lightning. PMID:25607345

Scaling of Dielectric Breakdown Thresholds in Earth's and CO2-rich atmospheres: Impact for Predictions of Extraterrestrial Transient Luminous Events and Lightning Discharges

NASA Astrophysics Data System (ADS)

Riousset, J. A.

2016-12-01

Earth's atmospheric electricity manifests itself in the form of glow, corona, streamer, and leader discharges observed as Saint Elmo's fire, sprites, lightning and jets discharges, and other Transient Luminous Events (TLEs). All of these are types of dielectric breakdown, but are governed by different physics. In particular, their initiation is associated with the crossing of specific electric field thresholds: relativistic runaway, streamer propagation, conventional breakdown, or thermal runaway thresholds, some better understood than others. For example, the initiation of a lightning discharge is known to occur when the local electric field exceeds a value similar to relativistic runaway field, but the exact threshold, as well as the physical mechanisms at work, remain rather unclear to date. Scaling laws for electric fields (and other quantities) have been established by Pasko et al. [GRL, 25(12), 2123-2126, 1998] and Pasko [NATO Sci. Series, Springer, 253-311, 2006]. In this work, we develop profiles for initiation criteria in air and in other atmospheric environments. We further calculate their associated scaling laws to determine the ability to trigger lightning flashes and TLEs in our solar system. This lets us predict the likelihood of electrical discharges on, e.g., Mars, Venus and Titan, and calculate the expected electric field conditions, under which discharges have been observed on Jupiter, Saturn, Uranus, and Neptune [Leblanc et al., ISSI Spa. Sci. Series, Springer, 2008, Yair, Adv. Space Res., 50(3), 293-310, 2012]. Our results anticipate the arrival of ExoMars 2016's Schiaparelli module, which will provide the first records of electric field at the surface of the planet [Déprez et al., EGU GA, 16, 16613, 2014]. This research is also motived by the increasing probability of manned missions to Mars and the potential electrostatic hazards it may face [Yair, 2012], and by the role of electrical discharges in the creation of active radicals, some of which may be of biological importance [Miller, Science, 117, 528-529, 1953; Biochem. Biophys. Acta, 23, 480-489, 1957].

Electron distribution functions in electric field environments

NASA Technical Reports Server (NTRS)

Rudolph, Terence H.

1991-01-01

The amount of current carried by an electric discharge in its early stages of growth is strongly dependent on its geometrical shape. Discharges with a large number of branches, each funnelling current to a common stem, tend to carry more current than those with fewer branches. The fractal character of typical discharges was simulated using stochastic models based on solutions of the Laplace equation. Extension of these models requires the use of electron distribution functions to describe the behavior of electrons in the undisturbed medium ahead of the discharge. These electrons, interacting with the electric field, determine the propagation of branches in the discharge and the way in which further branching occurs. The first phase in the extension of the referenced models , the calculation of simple electron distribution functions in an air/electric field medium, is discussed. Two techniques are investigated: (1) the solution of the Boltzmann equation in homogeneous, steady state environments, and (2) the use of Monte Carlo simulations. Distribution functions calculated from both techniques are illustrated. Advantages and disadvantages of each technique are discussed.

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

NASA Astrophysics Data System (ADS)

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.

Parts, Materials, and Processes Control Program for Expendable Launch Vehicles

DTIC Science & Technology

2015-07-31

burn-in, electrical tests (DWV, room and hot IR, partial discharge when in corona region); perform DPA with SEM/EDX analysis of dielectric...life test; x-ray and vicinal illumination inspection; electrical tests (DWV, room and hot IR, partial discharge when in corona region) Termination...defects; proper voltage derating. Partial discharge testing, corona inception testing up to 60% of rated voltage; CSAM screening; voltage burn

Discharge in Long Air Gaps; Modelling and applications

NASA Astrophysics Data System (ADS)

Beroual, A.; Fofana, I.

2016-06-01

Discharge in Long Air Gaps: Modelling and applications presents self-consistent predictive dynamic models of positive and negative discharges in long air gaps. Equivalent models are also derived to predict lightning parameters based on the similarities between long air gap discharges and lightning flashes. Macroscopic air gap discharge parameters are calculated to solve electrical, empirical and physical equations, and comparisons between computed and experimental results for various test configurations are presented and discussed. This book is intended to provide a fresh perspective by contributing an innovative approach to this research domain, and universities with programs in high-voltage engineering will find this volume to be a working example of how to introduce the basics of electric discharge phenomena.

Electric organ discharges and near-field spatiotemporal patterns of the electromotive force in a sympatric assemblage of Neotropical electric knifefish.

PubMed

Waddell, Joseph C; Rodríguez-Cattáneo, Alejo; Caputi, Angel A; Crampton, William G R

2016-10-01

Descriptions of the head-to-tail electric organ discharge (ht-EOD) waveform - typically recorded with electrodes at a distance of approximately 1-2 body lengths from the center of the subject - have traditionally been used to characterize species diversity in gymnotiform electric fish. However, even taxa with relatively simple ht-EODs show spatiotemporally complex fields near the body surface that are determined by site-specific electrogenic properties of the electric organ and electric filtering properties of adjacent tissues and skin. In Brachyhypopomus, a pulse-discharging genus in the family Hypopomidae, the regional characteristics of the electric organ and the role that the complex 'near field' plays in communication and/or electrolocation are not well known. Here we describe, compare, and discuss the functional significance of diversity in the ht-EOD waveforms and near-field spatiotemporal patterns of the electromotive force (emf-EODs) among a species-rich sympatric community of Brachyhypopomus from the upper Amazon. Copyright © 2016 Elsevier Ltd. All rights reserved.

Role of electric discharges in the generation of atmospheric vortices

NASA Astrophysics Data System (ADS)

Sinkevich, O. A.; Maslov, S. A.; Gusein-zade, N. G.

2017-02-01

The existing thermohydrodynamic and hydroelectromagnetic models of tornado are considered. The potentialities of the humid atmosphere as a heat engine generating air vortices are analyzed in detail. The ability of long-term atmospheric electric discharges to form a tornado funnel and create an initial twist of up to 10-3-10-2 s-1 in it are estimated. The possible effect of a lightning discharge on the initiation and evolution of the tornado is discussed. It is shown that the electric current flowing along the lightning channel can lead to helical instability and generation of a weak primary vortex. The channel formed in the atmosphere by a lightning discharge and the vortex motion of the parent thundercloud can enhance the primary vortex and promote its transformation into a tornado. Possible mechanisms of enhancement of the primary vortex created by a lightning discharge and the possibility of its transformation into a tornado in the postdischarge stage are discussed.

Post-breakdown secondary discharges at the electrode/dielectric interface of a cylindrical barrier discharge

NASA Astrophysics Data System (ADS)

Carman, Robert; Ward, Barry; Kane, Deborah

2011-10-01

The electrical breakdown characteristics of a double-walled cylindrical dielectric barrier discharge (DBD) lamp with a neon buffer gas under pulsed voltage excitation have been investigated. Following the formation of plasma in the main discharge gap, we have observed secondary breakdown phenomena at the inner and outer mesh electrode/dielectric interfaces under specific operating conditions. Plasma formation at these interfaces is investigated by monitoring the Ozone production rate in controlled flows of ultra high purity oxygen together with the overall electrical voltage-charge characteristics of the lamp. The results show that this secondary breakdown only occurs after the main discharge plasma has been established, and that significant electrical power may be dissipated in generating these spurious secondary plasmas. The results are important with regards to optimising the design and identifying efficient operating regimes of DBD based devices that employ mesh-type or wire/strip electrodes.

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

NASA Astrophysics Data System (ADS)

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-pressure Raman cell, providing access only to a few N2 rotational levels. Because of this, the four-wave mixing signal in the flame is lower by more than an order of magnitude compared to the signal generated in room temperature air plasma. Preliminary experiments demonstrated four-wave mixing signal generated by the electric field in the flame, following ns pulse discharge breakdown. The electric field in the flame is estimated using four-wave mixing signal calibration vs. temperature in electrostatic electric field generated in heated air. Further measurements in the flame are underway.

Capacitor discharge process for welding braided cable

DOEpatents

Wilson, Rick D.

1995-01-01

A capacitor discharge process for welding a braided cable formed from a plurality of individual cable strands to a solid metallic electrically conductive member comprises the steps of: (a) preparing the electrically conductive member for welding by bevelling one of its end portions while leaving an ignition projection extending outwardly from the apex of the bevel; (b) clamping the electrically conductive member in a cathode fixture; (c) connecting the electrically conductive member clamped in the cathode fixture to a capacitor bank capable of being charged to a preselected voltage value; (d) preparing the braided cable for welding by wrapping one of its end portions with a metallic sheet to form a retaining ring operable to maintain the individual strands of the braided cable in fixed position within the retaining ring; (e) clamping the braided cable and the retaining ring as a unit in an anode fixture so that the wrapped end portion of the braided cable faces the ignition projection of the electrically conductive member; and (f) moving the cathode fixture towards the anode fixture until the ignition projection of the electrically conductive member contacts the end portion of the braided cable thereby allowing the capacitor bank to discharge through the electrically conductive member and through the braided cable and causing the electrically conductive member to be welded to the braided cable via capacitor discharge action.

Electrical equivalent circuit for microstrip micro-plasma: control of EM propagation and numerical simulations.

PubMed

Mohamad, Almustafa; Tân-Hoa, Vuong; Jacques, David

2012-01-01

An approach to determine an equivalent electrical circuit of a micro planar discharge on a microstrip printed circuit is reported. The micro discharge is used to realize a dynamic microwave switching circuit. This approach is based on the measurement of the discharge current and the transmission coefficient for a given frequency 2.45 GHz. Numerical methods like FEM can be used to study the effect of plasma parameters on the propagation of electromagnetic waves through a microstrip printed circuit. Plasma behaves as flexible elements that can change its electrical proprieties such as conductivity.

Prebreakdown characteristics of weakly ionized liquid and gaseous media in the strongly nonuniform electric field

NASA Astrophysics Data System (ADS)

Apfelbaum, M. S.; Syrovatka, R. A.; Vladimirov, V. I.

2018-01-01

A theoretical model of electrohydrodynamic prebreakdown phenomena in slightly ionized (weakly conductive) media is proposed. The electric high voltage conduction of weakly conductive liquids and slightly ionized gases in intense electric fields using this model is considered. The formula for the calculations of volt-ampere characteristics under high voltage spherical capacitor field is analytically obtained. The experimental corona discharge volt-ampere characteristics of air are presented. It was found that the size of the ionization region in the case of corona discharge in air increases monotonically with increasing discharge voltage.

Inductive gas line for pulsed lasers

DOEpatents

Benett, William J.; Alger, Terry W.

1985-01-01

A gas laser having a metal inlet gas feed line assembly shaped as a coil, to function as an electrical inductance and therefore high impedance to pulses of electric current applied to electrodes at opposite ends of a discharge tube of a laser, for example. This eliminates a discharge path for the laser through the inlet gas feed line. A ferrite core extends through the coil to increase the inductance of the coil and provide better electric isolation. By elimination of any discharge breakdown through the gas supply, efficiency is increased and a significantly longer operating lifetime of the laser is provided.

Inductive gas line for pulsed lasers

DOEpatents

Benett, W.J.; Alger, T.W.

1982-09-29

A gas laser having a metal inlet gas feed line assembly shaped as a coil, to function as an electrical inductance and therefore high impedance to pulses of electric current applied to electrodes at opposite ends of a discharge tube of a laser, for example. This eliminates a discharge path for the laser through the inlet gas feed line. A ferrite core extends through the coil to increase the inductance of the coil and provide better electric isolation. By elimination of any discharge breakdown through the gas supply, efficiency is increased and a significantly longer operating lifetime of the laser is provided.

Exploration to generate atmospheric pressure glow discharge plasma in air

NASA Astrophysics Data System (ADS)

Wenzheng, LIU; Chuanlong, MA; Shuai, ZHAO; Xiaozhong, CHEN; Tahan, WANG; Luxiang, ZHAO; Zhiyi, LI; Jiangqi, NIU; Liying, ZHU; Maolin, CHAI

2018-03-01

Atmospheric pressure glow discharge (APGD) plasma in air has high application value. In this paper, the methods of generating APGD plasma in air are discussed, and the characteristics of dielectric barrier discharge (DBD) in non-uniform electric field are studied. It makes sure that APGD in air is formed by DBD in alternating current electric field with using the absorbing electron capacity of electret materials to provide initial electrons and to end the discharge progress. Through designing electric field to form two-dimensional space varying electric field and three-dimensional space varying electric field, the development of electron avalanches in air-gap is suppressed effectively and a large space of APGD plasma in air is generated. Further, through combining electrode structures, a large area of APGD plasma in air is generated. On the other hand, by using the method of increasing the density of initial electrons, millimeter-gap glow discharge in atmospheric pressure air is formed, and a maximum gap distance between electrodes is 8 mm. By using the APGD plasma surface treatment device composed of contact electrodes, the surface modification of high polymer materials such as aramid fiber and polyester are studied and good effect of modifications is obtained. The present paper provides references for the researchers of industrial applications of plasma.

Partial Discharge Characteristics of Polymer Nanocomposite Materials in Electrical Insulation: A Review of Sample Preparation Techniques, Analysis Methods, Potential Applications, and Future Trends

PubMed Central

Izzati, Wan Akmal; Adzis, Zuraimy; Shafanizam, Mohd

2014-01-01

Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends. PMID:24558326

Anticipating electrical breakdown in dielectric elastomer actuators

NASA Astrophysics Data System (ADS)

Muffoletto, Daniel P.; Burke, Kevin M.; Zirnheld, Jennifer L.

2013-04-01

The output strain of a dielectric elastomer actuator is directly proportional to the square of its applied electric field. However, since the likelihood of electric breakdown is elevated with an increased applied field, the maximum operating electric field of the dielectric elastomer is significantly derated in systems employing these actuators so that failure due to breakdown remains unlikely even as the material ages. In an effort to ascertain the dielectric strength so that stronger electric fields can be applied, partial discharge testing is used to assess the health of the actuator by detecting the charge that is released when localized instances of breakdown partially bridge the insulator. Pre-stretched and unstretched samples of VHB4910 tape were submerged in dielectric oil to remove external sources of partial discharges during testing, and the partial discharge patterns were recorded just before failure of the dielectric sample.

Electric organ discharge diversification in mormyrid weakly electric fish is associated with differential expression of voltage-gated ion channel genes.

PubMed

Nagel, Rebecca; Kirschbaum, Frank; Tiedemann, Ralph

2017-03-01

In mormyrid weakly electric fish, the electric organ discharge (EOD) is used for species recognition, orientation and prey localization. Produced in the muscle-derived adult electric organ, the EOD exhibits a wide diversity across species in both waveform and duration. While certain defining EOD characteristics can be linked to anatomical features of the electric organ, many factors underlying EOD differentiation are yet unknown. Here, we report the differential expression of 13 Kv1 voltage-gated potassium channel genes, two inwardly rectifying potassium channel genes, two previously studied sodium channel genes and an ATPase pump in two sympatric species of the genus Campylomormyrus in both the adult electric organ and skeletal muscle. Campylomormyrus compressirostris displays a basal EOD, largely unchanged during development, while C. tshokwe has an elongated, putatively derived discharge. We report an upregulation in all Kv1 genes in the electric organ of Campylomormyrus tshokwe when compared to both skeletal muscle and C. compressirostris electric organ. This pattern of upregulation in a species with a derived EOD form suggests that voltage-gated potassium channels are potentially involved in the diversification of the EOD signal among mormyrid weakly electric fish.

Carbon Coating Of Copper By Arc-Discharge Pyrolysis

NASA Technical Reports Server (NTRS)

Ebihara, Ben T.; Jopek, Stanley

1988-01-01

Adherent, abrasion-resistant coat deposited with existing equipment. Carbon formed and deposited as coating on copper substrate by pyrolysis of hydrocarbon oil in electrical-arc discharges. Technique for producing carbon deposits on copper accomplished with electrical-discharge-machining equipment used for cutting metals. Applications for new coating technique include the following: solar-energy-collecting devices, coating of metals other than copper with carbon, and carburization of metal surfaces.

Photo-triggering and secondary electron produced ionization in electric discharge ArF* excimer lasers

NASA Astrophysics Data System (ADS)

Xiong, Zhongmin; Kushner, Mark J.

2011-10-01

Electric discharge excimer lasers are sustained in multi-atmosphere attaching gas mixtures that are typically preionized to enable a reproducible, uniform glow, which maximizes optical quality and gain. This preionization is often accomplished using UV light produced by a corona discharge within the plasma cavity. To quantify the relationship between corona discharge properties and those of the laser discharge, the triggering of electron avalanche by preionizing UV light in an electric discharge-pumped ArF* excimer laser was numerically investigated using a two-dimensional model. The preionizing UV fluxes were generated by a corona-bar discharge driven by the same voltage pulse as the main discharge sustained in a multi-atmospheric Ne/Ar/Xe/F2 gas mixture. The resulting peak photo-electron density in the inter-electrode spacing is around 108 cm-3, and its distribution is biased toward the UV source. The preionization density increases with increasing dielectric constant and capacitance of the corona bar. The symmetry and uniformity of the discharge are, however, improved significantly once the main avalanche develops. In addition to bulk electron impact ionization, the ionization generated by sheath accelerated secondary electrons was found to be important in sustaining the discharge current at experimentally observed values. At peak current, the magnitude of the ionization by sheath accelerated electrons is comparable to that from bulk electron impact in the vicinity of the cathode.

Underwater microscopy for in situ studies of benthic ecosystems

NASA Astrophysics Data System (ADS)

Mullen, Andrew D.; Treibitz, Tali; Roberts, Paul L. D.; Kelly, Emily L. A.; Horwitz, Rael; Smith, Jennifer E.; Jaffe, Jules S.

2016-07-01

Microscopic-scale processes significantly influence benthic marine ecosystems such as coral reefs and kelp forests. Due to the ocean's complex and dynamic nature, it is most informative to study these processes in the natural environment yet it is inherently difficult. Here we present a system capable of non-invasively imaging seafloor environments and organisms in situ at nearly micrometre resolution. We overcome the challenges of underwater microscopy through the use of a long working distance microscopic objective, an electrically tunable lens and focused reflectance illumination. The diver-deployed instrument permits studies of both spatial and temporal processes such as the algal colonization and overgrowth of bleaching corals, as well as coral polyp behaviour and interspecific competition. By enabling in situ observations at previously unattainable scales, this instrument can provide important new insights into micro-scale processes in benthic ecosystems that shape observed patterns at much larger scales.

Multiplex electric discharge gas laser system

NASA Technical Reports Server (NTRS)

Laudenslager, James B. (Inventor); Pacala, Thomas J. (Inventor)

1987-01-01

A multiple pulse electric discharge gas laser system is described in which a plurality of pulsed electric discharge gas lasers are supported in a common housing. Each laser is supplied with excitation pulses from a separate power supply. A controller, which may be a microprocessor, is connected to each power supply for controlling the application of excitation pulses to each laser so that the lasers can be fired simultaneously or in any desired sequence. The output light beams from the individual lasers may be combined or utilized independently, depending on the desired application. The individual lasers may include multiple pairs of discharge electrodes with a separate power supply connected across each electrode pair so that multiple light output beams can be generated from a single laser tube and combined or utilized separately.

Customized electric power storage device for inclusion in a microgrid

DOEpatents

Goldsmith, Steven Y.; Wilson, David; Robinett, III, Rush D.

2017-08-01

An electric power storage device included in a microgrid is described herein. The electric power storage device has at least one of a charge rate, a discharge rate, or a power retention capacity that has been customized for the microgrid. The at least one of the charge rate, the discharge rate, or the power retention capacity of the electric power storage device is computed based at least in part upon specified power source parameters in the microgrid and specified load parameters in the microgrid.

Critical analysis of partial discharge dynamics in air filled spherical voids

NASA Astrophysics Data System (ADS)

Callender, G.; Golosnoy, I. O.; Rapisarda, P.; Lewin, P. L.

2018-03-01

In this paper partial discharge (PD) is investigated inside a spherical air filled void at atmospheric pressure using a drift diffusion model. Discharge dynamics consisted of an electron avalanche transitioning into positive streamer, in agreement with earlier work on dielectric barrier discharges. Different model configurations were utilised to test many of the concepts employed in semi-analytical PD activity models, which use simplistic descriptions of the discharge dynamics. The results showed that many of these concepts may be erroneous, with significant discrepancies between the canonical reasoning and the simulation results. For example, the residual electric field, the electric field after a discharge, is significantly lower than the estimates used by classical PD activity models in the literature.

Nighttime observations of thunderstorm electrical activity from a high altitude airplane

NASA Technical Reports Server (NTRS)

Brook, M.; Vonnegut, B.; Orville, R. E.; Vaughan, O. H., Jr.

1984-01-01

Nocturnal thunderstorms were observed from above and features of cloud structure and lightning which are not generally visible from the ground are discussed. Most, lightning activity seems to be associated with clouds with strong convective cauliflower tops. In both of the storms lightning channels were visible in the clear air above the cloud. It is shown that substances produced by thunderstorm electrical discharges can be introduced directly into the stratosphere. The cause and nature of the discharges above the cloud are not clear. They may be produced by accumulations of space charge in the clear air above the cloud. The discharges may arise solely because of the intense electric fields produced by charges within the cloud. In the latter case the ions introduced by these discharges will increase the electrical conductivity of the air above the cloud and increase the conduction current that flows from the cloud to the electrosphere. More quantitative data at higher resolution may show significant spectral differences between cloud to ground and intracloud strokes. It is shown that electric field change data taken with an electric field change meter mounted in an airplane provide data on lightning discharges from above that are quite similar to those obtained from the ground in the past. The optical signals from dart leaders, from return strokes, and from continuing currents are recognizable, can be used to provide information on the fine structure of lightning, and can be used to distinguish between cloud to ground and intracloud flashes.

Charging of moving surfaces by corona discharges sustained in air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jun-Chieh, E-mail: junchwan@umich.edu; Kushner, Mark J., E-mail: mjkush@umich.edu; Zhang, Daihua, E-mail: dhzhang@tju.edu.cn

Atmospheric pressure corona discharges are used in electrophotographic (EP) printing technologies for charging imaging surfaces such as photoconductors. A typical corona discharge consists of a wire (or wire array) biased with a few hundred volts of dc plus a few kV of ac voltage. An electric discharge is produced around the corona wire from which electrons drift towards and charge the underlying dielectric surface. The surface charging reduces the voltage drop across the gap between the corona wire and the dielectric surface, which then terminates the discharge, as in a dielectric barrier discharge. In printing applications, this underlying surface ismore » continuously moving throughout the charging process. For example, previously charged surfaces, which had reduced the local electric field and terminated the local discharge, are translated out of the field of view and are replaced with uncharged surface. The uncharged surface produces a rebound in the electric field in the vicinity of the corona wire which in turn results in re-ignition of the discharge. The discharge, so reignited, is then asymmetric. We found that in the idealized corona charging system we investigated, a negatively dc biased corona blade with a dielectric covered ground electrode, the discharge is initially sustained by electron impact ionization from the bulk plasma and then dominated by ionization from sheath accelerated secondary electrons. Depending on the speed of the underlying surface, the periodic re-ignition of the discharge can produce an oscillatory charging pattern on the moving surface.« less

46 CFR 111.30-29 - Emergency switchboards.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS... regulator unit acting on the exciter field, each emergency switchboard must have: (1) A generator field rheostat; (2) A double pole field switch; (3) Discharge clips; and (4) A discharge resistor. (g) Each...

46 CFR 111.30-29 - Emergency switchboards.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS... regulator unit acting on the exciter field, each emergency switchboard must have: (1) A generator field rheostat; (2) A double pole field switch; (3) Discharge clips; and (4) A discharge resistor. (g) Each...

Experimental investigation on electrical characteristics and dose measurement of dielectric barrier discharge plasma device used for therapeutic application

NASA Astrophysics Data System (ADS)

Shahbazi Rad, Zahra; Abbasi Davani, Fereydoun

2017-04-01

In this research, a Dielectric Barrier Discharge (DBD) plasma device operating in air has been made. The electrical characteristics of this device like instantaneous power, dissipated power, and discharge capacitance have been measured. Also, the effects of applied voltage on the dissipated power and discharge capacitance of the device have been investigated. The determination of electrical parameters is important in DBD plasma device used in living tissue treatment for choosing the proper treatment doses and preventing the destructive effects. The non-thermal atmospheric pressure DBD plasma source was applied for studying the acceleration of blood coagulation time, in vitro and wound healing time, in vivo. The citrated blood drops coagulated within 5 s treatment time by DBD plasma. The effects of plasma temperature and electric field on blood coagulation have been studied as an affirmation of the applicability of the constructed device. Also, the effect of constructed DBD plasma on wound healing acceleration has been investigated.

Experimental investigation on electrical characteristics and dose measurement of dielectric barrier discharge plasma device used for therapeutic application.

PubMed

Shahbazi Rad, Zahra; Abbasi Davani, Fereydoun

2017-04-01

In this research, a Dielectric Barrier Discharge (DBD) plasma device operating in air has been made. The electrical characteristics of this device like instantaneous power, dissipated power, and discharge capacitance have been measured. Also, the effects of applied voltage on the dissipated power and discharge capacitance of the device have been investigated. The determination of electrical parameters is important in DBD plasma device used in living tissue treatment for choosing the proper treatment doses and preventing the destructive effects. The non-thermal atmospheric pressure DBD plasma source was applied for studying the acceleration of blood coagulation time, in vitro and wound healing time, in vivo. The citrated blood drops coagulated within 5 s treatment time by DBD plasma. The effects of plasma temperature and electric field on blood coagulation have been studied as an affirmation of the applicability of the constructed device. Also, the effect of constructed DBD plasma on wound healing acceleration has been investigated.

Navigation by light polarization in clear and turbid waters

PubMed Central

Lerner, Amit; Sabbah, Shai; Erlick, Carynelisa; Shashar, Nadav

2011-01-01

Certain terrestrial animals use sky polarization for navigation. Certain aquatic species have also been shown to orient according to a polarization stimulus, but the correlation between underwater polarization and Sun position and hence the ability to use underwater polarization as a compass for navigation is still under debate. To examine this issue, we use theoretical equations for per cent polarization and electric vector (e-vector) orientation that account for the position of the Sun, refraction at the air–water interface and Rayleigh single scattering. The polarization patterns predicted by these theoretical equations are compared with measurements conducted in clear and semi-turbid coastal sea waters at 2 m and 5 m depth over sea floors of 6 m and 28 m depth. We find that the per cent polarization is correlated with the Sun's elevation only in clear waters. We furthermore find that the maximum value of the e-vector orientation angle equals the angle of refraction only in clear waters, in the horizontal viewing direction, over the deeper sea floor. We conclude that navigation by use of underwater polarization is possible under restricted conditions, i.e. in clear waters, primarily near the horizontal viewing direction, and in locations where the sea floor has limited effects on the light's polarization. PMID:21282170

Digital sonar system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, K.K.; Wilkes, R.J.

1995-11-21

A transponder of an active digital sonar system identifies a multifrequency underwater activating sonar signal received from a remote sonar transmitter. The transponder includes a transducer that receives acoustic waves, including the activating sonar signal, and generates an analog electrical receipt signal. The analog electrical receipt signal is converted to a digital receipt signal and cross-correlated with a digital transmission signal pattern corresponding to the activating sonar signal. A relative peak in the cross-correlation value is indicative of the activating sonar signal having been received by the transponder. In response to identifying the activating sonar signal, the transponder transmits amore » responding multifrequency sonar signal. 4 figs.« less

Air-jet power ultrasonic field applied to electrical discharge

NASA Astrophysics Data System (ADS)

Balek, Rudolf; Pekarek, Stanislav

2010-01-01

We describe a new setup of the Hartmann air-jet ultrasonic generator combined with electrical discharge in the nozzle-resonator gap. Using the schlieren visualization of air jet and ultrasonic field we investigated the shape and structure of the discharge and we determined relationship among the acoustic field in the nozzle-resonator gap, generator ultrasonic emission and discharge behavior. Apart of the fact that the discharge in the nozzle-resonator gap is stabilized and becomes more uniform, it increases its volume when the generator works in the regime of ultrasonic emission. At the same time the discharge light emission distribution is more over uniform in the gap. In the regime without the ultrasonic emission the discharge light emission is fragmented. We also found that the impedance of the discharge is decreased in case when the generator works in the regime of ultrasonic emission.

Hybrid nanocomposites based on electroactive hydrogels and cellulose nanocrystals for high-sensitivity electro-mechanical underwater actuation

NASA Astrophysics Data System (ADS)

Santaniello, Tommaso; Migliorini, Lorenzo; Locatelli, Erica; Monaco, Ilaria; Yan, Yunsong; Lenardi, Cristina; Comes Franchini, Mauro; Milani, Paolo

2017-08-01

We report the synthesis, fabrication and characterization of a hybrid hydrogel/cellulose nanocomposite, which exhibits high-performance electro-mechanical underwater actuation and high sensitivity in response to electrical stimuli below the standard potential of water electrolysis. The macromolecular structure of the material is constituted by an electroactive hydrogel, obtained through a photo-polymerization reaction with the use of three vinylic co-monomers: Na-4-vinylbenzenesulfonate, 2-hydroxyethylmethacrylate, and acrylonitrile. Different amounts (from 0.1% to 1.4% w/w) of biodegradable cellulose nanocrystals (CNCs) with sulfonate surface groups, obtained through the acidic hydrolysis of sulphite pulp lapsheets, are physically incorporated into the gel matrix during the synthesis step. Freestanding thin films of the nanocomposites are molded, and their swelling, mechanical and responsive properties are fully characterized. We observed that the embedding of the CNCs enhanced both the material Young’s modulus and its sensitivity to the applied electric field in the sub-volt regime (down to 5 mV cm-1). A demonstrator integrating multiple actuators that cooperatively bend together, mimicking the motion of an electro-valve, is also prototyped and tested. The presented nanocomposite is suitable for the development of soft smart components for bio-robotic applications and cells-based and bio-hybrid fluidic devices fabrication.

Nifekalant hydrochloride suppresses severe electrical storm in patients with malignant ventricular tachyarrhythmias.

PubMed

Washizuka, Takashi; Chinushi, Masaomi; Watanabe, Hiroshi; Hosaka, Yukio; Komura, Satoru; Sugiura, Hirotaka; Hirono, Takashi; Furushima, Hiroshi; Tanabe, Yasutaka; Aizawa, Yoshifusa

2005-12-01

Some patients with an implantable cardioverter-defibrillator (ICD) suffer from burst of inappropriate multiple discharges (severe electrical storm), and because the current therapeutic options are limited, the effect of nifekalant hydrochloride, a new class III drug, on severe electrical storm was investigated in the present study. Ninety-one consecutive patients treated with ICD were included in the study (M 70; mean age 58 years; left ventricular ejection fraction 45+/-15%). Severe electrical storm was defined as more than 10 ICD discharges within 1 h. During a mean follow-up period of 30+/-13 months, 41/91 (45%) patients had appropriate ICD therapy for arrhythmias and severe electrical storm occurred in 11 of them (12%) at 20+/-18 months after ICD implantation. The mean number of ICD discharges/h during severe electrical storm was 18+/-12. In 4 of 10 patients, severe electrical storm was successfully suppressed by a combination of deep sedation and beta-blocking agent; 6 other patients were refractory to this treatment, but severe electrical storm was successfully suppressed by intravenous administration of nifekalant hydrochloride with no adverse effects. Nifekalant hydrochloride is an effective and safe treatment for severe electrical storm.

Particle based plasma simulation for an ion engine discharge chamber

NASA Astrophysics Data System (ADS)

Mahalingam, Sudhakar

Design of the next generation of ion engines can benefit from detailed computer simulations of the plasma in the discharge chamber. In this work a complete particle based approach has been taken to model the discharge chamber plasma. This is the first time that simplifying continuum assumptions on the particle motion have not been made in a discharge chamber model. Because of the long mean free paths of the particles in the discharge chamber continuum models are questionable. The PIC-MCC model developed in this work tracks following particles: neutrals, singly charged ions, doubly charged ions, secondary electrons, and primary electrons. The trajectories of these particles are determined using the Newton-Lorentz's equation of motion including the effects of magnetic and electric fields. Particle collisions are determined using an MCC statistical technique. A large number of collision processes and particle wall interactions are included in the model. The magnetic fields produced by the permanent magnets are determined using Maxwell's equations. The electric fields are determined using an approximate input electric field coupled with a dynamic determination of the electric fields caused by the charged particles. In this work inclusion of the dynamic electric field calculation is made possible by using an inflated plasma permittivity value in the Poisson solver. This allows dynamic electric field calculation with minimal computational requirements in terms of both computer memory and run time. In addition, a number of other numerical procedures such as parallel processing have been implemented to shorten the computational time. The primary results are those modeling the discharge chamber of NASA's NSTAR ion engine at its full operating power. Convergence of numerical results such as total number of particles inside the discharge chamber, average energy of the plasma particles, discharge current, beam current and beam efficiency are obtained. Steady state results for the particle number density distributions and particle loss rates to the walls are presented. Comparisons of numerical results with experimental measurements such as currents and the particle number density distributions are made. Results from a parametric study and from an alternative magnetic field design are also given.

Phosphoric acid as an electrolyte additive for lead/acid batteries in electric-vehicle applications

NASA Astrophysics Data System (ADS)

Meissner, E.

The influence of the addition of phosphoric acid to the electrolyte on the performance of gelled lead/acid electric-vehiicle batteries is investigated. This additive reduces the reversible capacity decay of the positive electrode significantly which is observed upon extended cycling when recharge of the battery is performed at low initial rate. This is important when low-rate on-board chargers are used. Pulsed discharge, typical for electric-vehicle application, induces reversible capacity decay more than constant-current discharge at a same depth-of-discharge, as well with as without the addition of phosphoric acid. By contrast, hindrance in presence of H 3PO 4 for both the recharge and the discharge reaction helps to homogenize the state of many individual cells during cycling in long battery strings. Reversible capacity loss, which occurs after extended cycling and when pulsed discharge is applied, can be recovered by a single discharge at very low rate with batteries with and without the addition of phosphoric acid. The discharge-rate dependency of the capacity is significantly reduced when phosphoric acid is added. The pulse discharge behaviour may be better, even if the nominal capacity is reduced. The experimental findings of the influence of phosphoric acid addition is discussed in terms of the aggregate-of-spheres model of reversible capacity decay.

An experimental system for controlled exposure of biological samples to electrostatic discharges.

PubMed

Marjanovič, Igor; Kotnik, Tadej

2013-12-01

Electrostatic discharges occur naturally as lightning strokes, and artificially in light sources and in materials processing. When an electrostatic discharge interacts with living matter, the basic physical effects can be accompanied by biophysical and biochemical phenomena, including cell excitation, electroporation, and electrofusion. To study these phenomena, we developed an experimental system that provides easy sample insertion and removal, protection from airborne particles, observability during the experiment, accurate discharge origin positioning, discharge delivery into the sample either through an electric arc with adjustable air gap width or through direct contact, and reliable electrical insulation where required. We tested the system by assessing irreversible electroporation of Escherichia coli bacteria (15 mm discharge arc, 100 A peak current, 0.1 μs zero-to-peak time, 0.2 μs peak-to-halving time), and gene electrotransfer into CHO cells (7 mm discharge arc, 14 A peak current, 0.5 μs zero-to-peak time, 1.0 μs peak-to-halving time). Exposures to natural lightning stroke can also be studied with this system, as due to radial current dissipation, the conditions achieved by a stroke at a particular distance from its entry are also achieved by an artificial discharge with electric current downscaled in magnitude, but similar in time course, correspondingly closer to its entry. © 2013.

Discharge current distribution in stratified soil under impulse discharge

NASA Astrophysics Data System (ADS)

Eniola Fajingbesi, Fawwaz; Shahida Midi, Nur; Elsheikh, Elsheikh M. A.; Hajar Yusoff, Siti

2017-06-01

The mobility of charge particles traversing a material defines its electrical properties. Soil (earth) have long been the universal grounding before and after the inception of active ground systems for electrical appliance purpose due to it semi-conductive properties. The soil can thus be modelled as a single material exhibiting semi-complex inductive-reactive impedance. Under impulse discharge such as lightning strikes to soil this property of soil could result in electric potential level fluctuation ranging from ground potential rise/fall to electromagnetic pulse coupling that could ultimately fail connected electrical appliance. In this work we have experimentally model the soil and lightning discharge using point to plane electrode setup to observe the current distribution characteristics at different soil conductivity [mS/m] range. The result presented from this research indicate above 5% shift in conductivity before and after discharge which is significant for consideration when dealing with grounding designs. The current distribution in soil have also be successfully observed and analysed from experimental result using mean current magnitude in relation to electrode distance and location, current density variation with depth all showing strong correlation with theoretical assumptions of a semi-complex impedance material.

30 CFR 7.64 - Technical requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... voltage that can be applied across an electric contact that discharges a capacitor shall not be greater...) Capacitor discharge. The blasting unit shall include an automatic means to dissipate any electric charge remaining in any capacitor after the blasting unit is deenergized and not in use. (j) Construction. Blasting...

30 CFR 7.64 - Technical requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... voltage that can be applied across an electric contact that discharges a capacitor shall not be greater...) Capacitor discharge. The blasting unit shall include an automatic means to dissipate any electric charge remaining in any capacitor after the blasting unit is deenergized and not in use. (j) Construction. Blasting...

30 CFR 7.64 - Technical requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... voltage that can be applied across an electric contact that discharges a capacitor shall not be greater...) Capacitor discharge. The blasting unit shall include an automatic means to dissipate any electric charge remaining in any capacitor after the blasting unit is deenergized and not in use. (j) Construction. Blasting...

Electric oxygen-iodine laser discharge scaling and laser performance

NASA Astrophysics Data System (ADS)

Woodard, Brian S.

In 2004, a research partnership between the University of Illinois and CU Aerospace demonstrated the first electric discharge pumped oxygen-iodine laser referred to as ElectricOIL. This exciting improvement over the standard oxygen-iodine laser utilizes a gas discharge to produce the necessary electronically-excited molecular oxygen, O2(a 1Delta), that serves as the energy reservoir in the laser system. Pumped by a near-resonant energy transfer, the atomic iodine lases on the I(2P1/2) → I(2P3/2) transition at 1315 nm. Molecular oxygen diluted with helium and a small fraction of nitric oxide flows through a radiofrequency discharge where O2(a 1Delta) and many other excited species are created. Careful investigations to understand the benefits and problems associated with these other states in the laser system allowed this team to succeed where other research groups had failed, and after the initial demonstration, the ElectricOIL research focus shifted to increasing the efficiencies along with the output laser energy. Among other factors, the laser power scales with the flow rate of oxygen in the desired excited state. Therefore, high yields of O2(a 1Delta) are desired along with high input oxygen flow rates. In the early ElectricOIL experiments, the pressure in the discharge was approximately 10 Torr, but increased flow rates forced the pressure to between 50 and 60 Torr requiring a number of new discharge designs in order to produce similar yields of O2(a1Delta) efficiently. Experiments were conducted with only the electric discharge portion of the laser system using emission diagnostics to study the effects of changing the discharge geometry, flow residence time, and diluent. The power carried by O2(a 1Delta) is the maximum power that could be extracted from the laser, and the results from these studies showed approximately 2500 W stored in the O2(a1Delta) state. Transferring this energy into the atomic iodine has been another challenge in ElectricOIL as experiments have shown that the iodine is pumped into the excited state slower than is predicted by the known kinetics, resulting in reduced output power. An elementary model is presented that may partially explain this problem. Larger laser resonator volumes are employed to improve power extraction by providing more flow time for iodine pumping. The results presented in this work in conjunction with the efforts of others led to ElectricOIL scaling from 200 mW in the initial demonstration to nearly 500 W.

Electric resistivity and seismic refraction tomography: a challenging joint underwater survey at Äspö Hard Rock Laboratory

NASA Astrophysics Data System (ADS)

Ronczka, Mathias; Hellman, Kristofer; Günther, Thomas; Wisén, Roger; Dahlin, Torleif

2017-06-01

Tunnelling below water passages is a challenging task in terms of planning, pre-investigation and construction. Fracture zones in the underlying bedrock lead to low rock quality and thus reduced stability. For natural reasons, they tend to be more frequent at water passages. Ground investigations that provide information on the subsurface are necessary prior to the construction phase, but these can be logistically difficult. Geophysics can help close the gaps between local point information by producing subsurface images. An approach that combines seismic refraction tomography and electrical resistivity tomography has been tested at the Äspö Hard Rock Laboratory (HRL). The aim was to detect fracture zones in a well-known but logistically challenging area from a measuring perspective. The presented surveys cover a water passage along part of a tunnel that connects surface facilities with an underground test laboratory. The tunnel is approximately 100 m below and 20 m east of the survey line and gives evidence for one major and several minor fracture zones. The geological and general test site conditions, e.g. with strong power line noise from the nearby nuclear power plant, are challenging for geophysical measurements. Co-located positions for seismic and ERT sensors and source positions are used on the 450 m underwater section of the 700 m profile. Because of a large transition zone that appeared in the ERT result and the missing coverage of the seismic data, fracture zones at the southern and northern parts of the underwater passage cannot be detected by separated inversion. Synthetic studies show that significant three-dimensional (3-D) artefacts occur in the ERT model that even exceed the positioning errors of underwater electrodes. The model coverage is closely connected to the resolution and can be used to display the model uncertainty by introducing thresholds to fade-out regions of medium and low resolution. A structural coupling cooperative inversion approach is able to image the northern fracture zone successfully. In addition, previously unknown sedimentary deposits with a significantly large thickness are detected in the otherwise unusually well-documented geological environment. The results significantly improve the imaging of some geologic features, which would have been undetected or misinterpreted otherwise, and combines the images by means of cluster analysis into a conceptual subsurface model.

Parameters for Fabricating Nano-Au Colloids through the Electric Spark Discharge Method with Micro-Electrical Discharge Machining.

PubMed

Tseng, Kuo-Hsiung; Chung, Meng-Yun; Chang, Chaur-Yang

2017-06-02

In this study, the Electric Spark Discharge Method (ESDM) was employed with micro-electrical discharge machining (m-EDM) to create an electric arc that melted two electrodes in deionized water (DW) and fabricated nano-Au colloids through pulse discharges with a controlled on-off duration (T ON -T OFF ) and a total fabrication time of 1 min. A total of six on-off settings were tested under normal experimental conditions and without the addition of any chemical substances. Ultraviolet-visible spectroscopy (UV-Vis), Zetasizer Nano measurements, and scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analyses suggested that the nano-Au colloid fabricated at 10-10 µs (10 µs on, 10 µs off) had higher concentration and suspension stability than products made at other T ON -T OFF settings. The surface plasmon resonance (SPR) of the colloid was 549 nm on the first day of fabrication and stabilized at 532 nm on the third day. As the T ON -T OFF period increased, the absorbance (i.e., concentration) of all nano-Au colloids decreased. Absorbance was highest at 10-10 µs. The SPR peaks stabilized at 532 nm across all T ON -T OFF periods. The Zeta potential at 10-10 µs was -36.6 mV, indicating that no nano-Au agglomeration occurred and that the particles had high suspension stability.

Parameters for Fabricating Nano-Au Colloids through the Electric Spark Discharge Method with Micro-Electrical Discharge Machining

PubMed Central

Tseng, Kuo-Hsiung; Chung, Meng-Yun; Chang, Chaur-Yang

2017-01-01

In this study, the Electric Spark Discharge Method (ESDM) was employed with micro-electrical discharge machining (m-EDM) to create an electric arc that melted two electrodes in deionized water (DW) and fabricated nano-Au colloids through pulse discharges with a controlled on–off duration (TON–TOFF) and a total fabrication time of 1 min. A total of six on–off settings were tested under normal experimental conditions and without the addition of any chemical substances. Ultraviolet–visible spectroscopy (UV–Vis), Zetasizer Nano measurements, and scanning electron microscopy–energy dispersive X-ray (SEM–EDX) analyses suggested that the nano-Au colloid fabricated at 10–10 µs (10 µs on, 10 µs off) had higher concentration and suspension stability than products made at other TON–TOFF settings. The surface plasmon resonance (SPR) of the colloid was 549 nm on the first day of fabrication and stabilized at 532 nm on the third day. As the TON–TOFF period increased, the absorbance (i.e., concentration) of all nano-Au colloids decreased. Absorbance was highest at 10–10 µs. The SPR peaks stabilized at 532 nm across all TON–TOFF periods. The Zeta potential at 10–10 µs was −36.6 mV, indicating that no nano-Au agglomeration occurred and that the particles had high suspension stability. PMID:28574476

Electric discharge in water as a source of UV radiation, ozone and hydrogen peroxide

NASA Astrophysics Data System (ADS)

Anpilov, A. M.; Barkhudarov, E. M.; Bark, Yu B.; Zadiraka, Yu V.; Christofi, M.; Kozlov, Yu N.; Kossyi, I. A.; Kop'ev, V. A.; Silakov, V. P.; Taktakishvili, M. I.; Temchin, S. M.

2001-03-01

Results are presented from investigations of multispark electric discharge in water excited along multielectrode metal-dielectric systems with gas supply into the interelectrode gaps. The intensity distribution of discharge radiation in the region covering the biologically active soft UV (190≤λ≤430 nm) has been determined and the absolute number of quanta in this wavelength interval has been measured. The potentiality of the slipping surface discharge in water for its disinfection is analysed. The energy expenditure for water cleansing is estimated to be as low as ~10-4 kWh l-1.

Field strengths and dissipated powers in microwave-excited high-pressure sulphur discharges

NASA Astrophysics Data System (ADS)

van Dongen, Menno; Körber, Achim; van der Heijden, Harm; Jonkers, Jeroen; Scholl, Robert; van der Mullen, Joost

1998-11-01

A method which makes it is possible to measure the electric field strength in microwave discharges is presented. A condition for this method is that the plasma has such a low conductivity that the associated skin depth is larger than the discharge radius. It is found that the field strength in high-pressure sulphur lamps is around 400 V 0022-3727/31/21/015/img10. Furthermore, this method allows the determination of the power absorbed in the resonator's wall and in the plasma and the estimation of the effective electric conductivity in the discharge.

Flywheel Charge/Discharge Control Developed

NASA Technical Reports Server (NTRS)

Beach, Raymond.F.; Kenny, Barbara H.

2001-01-01

A control algorithm developed at the NASA Glenn Research Center will allow a flywheel energy storage system to interface with the electrical bus of a space power system. The controller allows the flywheel to operate in both charge and discharge modes. Charge mode is used to store additional energy generated by the solar arrays on the spacecraft during insolation. During charge mode, the flywheel spins up to store the additional electrical energy as rotational mechanical energy. Discharge mode is used during eclipse when the flywheel provides the power to the spacecraft. During discharge mode, the flywheel spins down to release the stored rotational energy.

Role of electric discharges in the generation of atmospheric vortices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinkevich, O. A., E-mail: oleg.sinkevich@itf.mpei.ac.ru; Maslov, S. A., E-mail: sergm90@mail.ru; Gusein-zade, N. G., E-mail: ngus@mail.ru

The existing thermohydrodynamic and hydroelectromagnetic models of tornado are considered. The potentialities of the humid atmosphere as a heat engine generating air vortices are analyzed in detail. The ability of long-term atmospheric electric discharges to form a tornado funnel and create an initial twist of up to 10{sup –3}–10{sup –2} s{sup –1} in it are estimated. The possible effect of a lightning discharge on the initiation and evolution of the tornado is discussed. It is shown that the electric current flowing along the lightning channel can lead to helical instability and generation of a weak primary vortex. The channel formedmore » in the atmosphere by a lightning discharge and the vortex motion of the parent thundercloud can enhance the primary vortex and promote its transformation into a tornado. Possible mechanisms of enhancement of the primary vortex created by a lightning discharge and the possibility of its transformation into a tornado in the postdischarge stage are discussed.« less

Capacitively coupled hydrogen plasmas sustained by tailored voltage waveforms: excitation dynamics and ion flux asymmetry

DOE PAGES

Bruneau, B.; Diomede, P.; Economou, D. J.; ...

2016-06-08

Parallel plate capacitively coupled plasmas in hydrogen at relatively high pressure (~1 Torr) are excited with tailored voltage waveforms containing up to five frequencies. Predictions of a hybrid model combining a particle-in-cell simulation with Monte Carlo collisions and a fluid model are compared to phase resolved optical emission spectroscopy measurements, yielding information on the dynamics of the excitation rate in these discharges. When the discharge is excited with amplitude asymmetric waveforms, the discharge becomes electrically asymmetric, with different ion energies at each of the two electrodes. Unexpectedly, large differences in themore » $$\\text{H}_{2}^{+}$$ fluxes to each of the two electrodes are caused by the different $$\\text{H}_{3}^{+}$$ energies. When the discharge is excited with slope asymmetric waveforms, only weak electrical asymmetry of the discharge is observed. In this case, electron power absorption due to fast sheath expansion at one electrode is balanced by electron power absorption at the opposite electrode due to a strong electric field reversal.« less

Recovery curves of the surface electric field after lightning discharges occurring between the positive charge pocket and negative charge centre in a thundercloud

NASA Astrophysics Data System (ADS)

Pawar, S. D.; Kamra, A. K.

2002-12-01

Surface observations of the electric field recovery curves of the lightning discharges occurring between the positive charge pocket and negative main charge centre in an overhead thundercloud are reported. Such recovery curves are observed to have an additional step of very slow field-change observed at an after-discharge value of electric field equal to 5-6 kV m-1. The behavior of recovery curves is explained in terms of the coronae charge and the relative efficiencies of the charge generating processes responsible for growth of positive charge pocket and main negative charge centre in the thundercloud. The charging currents responsible for the growth of charge in positive charge pockets is computed to be 2-4 times larger than that for the growth of the main negative charge. However, the charge destroyed in such a discharge is found to be comparable to that in a discharge between the main charge centres of the thundercloud.

Fast optical and electrical diagnostics of pulsed spark discharges in different gap geometries

NASA Astrophysics Data System (ADS)

Höft, Hans; Huiskamp, Tom; Kettlitz, Manfred

2016-09-01

Spark discharges in different electrode configurations and with various electrode materials were ignited in air at atmospheric pressure using a custom build pulse charger with 1 μs voltage rise time (up to 28 kV) in single shot operation. Fast voltage and current measurements were combined with iCCD imaging with high spatial resolution (better than 10 μm) on pin-to-pin, pin-to-half-sphere and symmetrical half-sphere tungsten electrodes and symmetrical half-sphere brass electrodes for electrode gaps of 0.1 to 0.7 mm. Breakdown voltages, consumed electrical energies and the discharge emission structures as well as the discharge diameters were obtained. Because of the synchronization of the electrical measurements and the iCCD imaging (i.e. one complete data set for every shot), it was possible to estimate the current density and the change of the discharge pattern, such as single or multiple channels, for all cases. EU funding under Grant No 316216 (PlasmaShape).

Boundary-value problem for a counterrotating electrical discharge in an axial magnetic field. [plasma centrifuge for isotope separation

NASA Technical Reports Server (NTRS)

Hong, S. H.; Wilhelm, H. E.

1978-01-01

An electrical discharge between two ring electrodes embedded in the mantle of a cylindrical chamber is considered, in which the plasma in the anode and cathode regions rotates in opposite directions under the influence of an external axial magnetic field. The associated boundary-value problem for the coupled partial differential equations describing the azimuthal velocity and radial current-density fields is solved in closed form. The velocity, current density, induced magnetic induction, and electric fields are presented for typical Hartmann numbers, magnetic Reynolds numbers, and geometry parameters. The discharge is shown to produce anodic and cathodic plasma sections rotating at speeds of the order 1,000,000 cm/sec for conventional magnetic field intensities. Possible application of the magnetoactive discharge as a plasma centrifuge for isotope separation is discussed.

Influence of an electric probe on the anode layer of a glow discharge in nitrogen

NASA Astrophysics Data System (ADS)

Taran, M. D.; Dyatko, N. A.; Kochetov, I. V.; Napartovich, A. P.; Akishev, Yu S.

2018-05-01

A two-dimensional (2D) numerical model of a DC glow discharge in nitrogen is developed for the case when the electric probe is mounted in the discharge gap. Within this model, calculations are performed for the gas pressure of 50 Torr and discharge current densities of 22 and 90 mA cm‑2. A cylindrical probe 1 mm in diameter is located parallel to the anode at a distance of 5 or 10 mm. The probe potential is varied in a wide range relative to the floating potential. Numerical simulations predict the 2D plasma perturbation pattern induced by the electric probe and the influence of the probe on anode layer characteristics. In particular, conditions are determined under which a region with no glow forms in the anode layer.

High Discharge Energy Density at Low Electric Field Using an Aligned Titanium Dioxide/Lead Zirconate Titanate Nanowire Array.

PubMed

Zhang, Dou; Liu, Weiwei; Guo, Ru; Zhou, Kechao; Luo, Hang

2018-02-01

Polymer-based capacitors with high energy density have attracted significant attention in recent years due to their wide range of potential applications in electronic devices. However, the obtained high energy density is predominantly dependent on high applied electric field, e.g., 400-600 kV mm -1 , which may bring more challenges relating to the failure probability. Here, a simple two-step method for synthesizing titanium dioxide/lead zirconate titanate nanowire arrays is exploited and a demonstration of their ability to achieve high discharge energy density capacitors for low operating voltage applications is provided. A high discharge energy density of 6.9 J cm -3 is achieved at low electric fields, i.e., 143 kV mm -1 , which is attributed to the high relative permittivity of 218.9 at 1 kHz and high polarization of 23.35 µC cm -2 at this electric field. The discharge energy density obtained in this work is the highest known for a ceramic/polymer nanocomposite at such a low electric field. The novel nanowire arrays used in this work are applicable to a wide range of fields, such as energy harvesting, energy storage, and photocatalysis.

Optical alignment of electrodes on electrical discharge machines

NASA Technical Reports Server (NTRS)

Boissevain, A. G.; Nelson, B. W.

1972-01-01

Shadowgraph system projects magnified image on screen so that alignment of small electrodes mounted on electrical discharge machines can be corrected and verified. Technique may be adapted to other machine tool equipment where physical contact cannot be made during inspection and access to tool limits conventional runout checking procedures.

Eight electrode optical readout gap

DOEpatents

Boettcher, G.E.; Crain, R.W.

1984-01-01

A protective device for a plurality of electrical circuits includes a plurality of isolated electrodes forming a gap with a common electrode. An output signal, electrically isolated from the circuits being monitored, is obtained by a photosensor viewing the discharge gap through an optical window. Radioactive stabilization of discharge characteristics is provided for slowly changing voltages and carbon tipped dynamic starters provide desirable discharge characteristics for rapidly varying voltages. A hydrogen permeation barrier is provided on external surfaces of the device.

Insulation Coordination and Failure Mitigation Concerns for Roust Dc Electrical Power Systems (Preprint)

DTIC Science & Technology

2014-05-01

vulnerable to failure is air. This could be a discharge through an air medium or along an air/surface interface. Achieving robustness in dc power...sputtering” arcs) are discharges that are most commonly located in series with the intended load; the electrical impedance of the load limits the...particularly those used at voltages > 1000 V, is detection and measurement of partial- discharge (PD) activity. The presence of PD in a component typically

Turbulent Flame Stabilization Methods Using Confinement, Diluents, and High-Potential Electric Fields

DTIC Science & Technology

2014-08-03

the corona discharge was optimal for flame stabilization when it was located where fuel/air mixtures were within flammability limits locally...field [56]. This ionic wind is also known as the “ corona wind” [57] due to the corona discharge that develops at the sharp edge of the charged... Corona Discharge ,” Transactions of the American Institute of Electrical Engineers, Part I: Communication and Electronics, vol. 80, no. 2, pp. 143-150

Ultraviolet radiation induced discharge laser

DOEpatents

Gilson, Verle A.; Schriever, Richard L.; Shearer, James W.

1978-01-01

An ultraviolet radiation source associated with a suitable cathode-anode electrode structure, disposed in a gas-filled cavity of a high pressure pulsed laser, such as a transverse electric atmosphere (TEA) laser, to achieve free electron production in the gas by photoelectric interaction between ultraviolet radiation and the cathode prior to the gas-exciting cathode-to-anode electrical discharge, thereby providing volume ionization of the gas. The ultraviolet radiation is produced by a light source or by a spark discharge.

[Anterior uveitis caused by electrical discharge in whole body injuries (fifteen years study)].

PubMed

Krásný, J; Brož, L; Kripner, J

2013-10-01

To inform about clinical analysis of early ophthalmologic complication (uveitis) in patients sustained electric discharge injury. The authors refer about fifteen years follow-up of pediatric patients at the Department of Burns Medicine, 3rd Medical Faculty, Charles University in Prague, Czech Republic, E.U., with electric discharge injury, in which the anterior uveitis was detected. Out of 43 patients after electric discharge injury, the always-unilateral iritis (iridocyclitis) was diagnosed in four (9 %) patients according to thorough going follow-up after first accidental diagnosis in the year 1998. Out of four boys aged 12 - 15 years, the first two were injured during the "play" - due to the contact with electrical trolley wire while running on railroad wagons roofs, and the two others were stuck by lighting under a tree by secondary electrical discharge. More serious skin burns were noticed in high-voltage current injury - 69 % or 55 % of body surface respectively, with the necessity of skin transplantation. The same was necessary in one boy injured by lighting with burns of 25 % of body surface, while the last one had on the skin the lighting signs only. In most of the patients, the resuscitation care due to unconsciousness and posttraumatic shock was necessary. The anterior uveitis was diagnosed subsequently, after initial preliminary diagnoses as conjunctivitis, episcleritis, or ophthalmia electrical. The iritis without visual function decrease was discovered in few days after the injury in three patients. Treatment and results: The inflammation was in these cases treated with short-term application of mydriatic and corticosteroid eye drops. Once only, the uveitis appeared after two months during the patients hospitalization and then the signs of iridocyclitis in the anterior chamber worsened and caused visual acuity decrease to hand movement in front of the eye. The condition was successfully treated by means of parabulbar betamethasone injection and long-term application of mydriatic and corticosteroid drops. Uveitis in electrical discharge injury of different origin is a rare early complication, which may be determined solely by regular ophthalmologic follow-up examinations of the patients.

Design of a secondary lens using gaussian function

NASA Astrophysics Data System (ADS)

Anh, Nguyen Doan Quoc; Long, Nguyen Ngoc; Van Phuoc, Nguyen; Voznak, Miroslav; Zdralek, Jaroslav

2018-04-01

In the article, it is recognized that the high-intensity discharge (HID) fishing lamp becomes obsolete, so we designed a free secondary lens for an LED fishing/working lamp (LFWL) to serve the lighting needs of fishing and the on-board activities on fishing boats through gaussian decomposition for taking the place it. The results proved that it is really useful to the board, sea-surface, and underwater. Moreover, the lighting efficiency of 91 % with the power consumption reducing more than 3 times could be achieved when the proposed LED fishing/working lamps are used instead of the HID fishing lamps.

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

PubMed Central

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

2016-01-01

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

Electrically Conductive Anodized Aluminum Surfaces

NASA Technical Reports Server (NTRS)

Nguyen, Trung Hung

2006-01-01

Anodized aluminum components can be treated to make them sufficiently electrically conductive to suppress discharges of static electricity. The treatment was conceived as a means of preventing static electric discharges on exterior satin-anodized aluminum (SAA) surfaces of spacecraft without adversely affecting the thermal-control/optical properties of the SAA and without need to apply electrically conductive paints, which eventually peel off in the harsh environment of outer space. The treatment can also be used to impart electrical conductivity to anodized housings of computers, medical electronic instruments, telephoneexchange equipment, and other terrestrial electronic equipment vulnerable to electrostatic discharge. The electrical resistivity of a typical anodized aluminum surface layer lies between 10(exp 11) and 10(exp 13) Omega-cm. To suppress electrostatic discharge, it is necessary to reduce the electrical resistivity significantly - preferably to < or = 10(exp 9) Omega-cm. The present treatment does this. The treatment is a direct electrodeposition process in which the outer anodized surface becomes covered and the pores in the surface filled with a transparent, electrically conductive metal oxide nanocomposite. Filling the pores with the nanocomposite reduces the transverse electrical resistivity and, in the original intended outer-space application, the exterior covering portion of the nanocomposite would afford the requisite electrical contact with the outer-space plasma. The electrical resistivity of the nanocomposite can be tailored to a value between 10(exp 7) and 10(exp 12) Omega-cm. Unlike electrically conductive paint, the nanocomposite becomes an integral part of the anodized aluminum substrate, without need for adhesive bonding material and without risk of subsequent peeling. The electrodeposition process is compatible with commercial anodizing production lines. At present, the electronics industry uses expensive, exotic, electrostaticdischarge- suppressing finishes: examples include silver impregnated anodized, black electroless nickel, black chrome, and black copper. In comparison with these competing finishes, the present nanocomposite finishes are expected to cost 50 to 20 percent less and to last longer.

Studies of oxygen-helium discharges for use in electric oxygen-iodine lasers

NASA Astrophysics Data System (ADS)

Zimmerman, Joseph William

In recent work, the performance of the Electric Oxygen-Iodine Laser (ElectricOIL), developed in partnership by researchers at the University of Illinois and CU Aerospace, has been greatly improved through systematic study of various components of this new laser technology. One major contribution to the advancement of ElectricOIL technology has been the development of electric discharges capable of producing significant flow rates of the precursor electronically-excited molecular oxygen, O2(a1Delta). O2(a 1Delta) serves as an energy reservoir in the laser system, pumping atomic iodine by near-resonant energy transfer producing gain and laser on the I(2P1/2) → I(2P3/2 ) transition at 1315 nm. Initial experimental work with radio-frequency discharges showed the importance of controlling O-atom flow rates to reduce quenching losses of energy stored in O2(a1Delta), and determined proper selection of the helium diluent ratio and specific power deposition (power per O2 flow rate). Further experimental investigations with transverse capacitive radio-frequency discharges in O2/He/NO mixtures in the pressure range of 1-100 Torr and power range of 0.1-1.2 kW have indicated that O2(a1Delta) production is a strong function of geometry (transverse gap), excitation frequency, and pressure. These parameters along with gas flow mixture dictate the current density at which the discharge operates, and its modal characteristics (normal vs. abnormal, homogeneous vs. inhomogeneous). A key result is that to encourage efficient O2(a1Delta) production these parameters should be selected in order to promote a homogeneous (low current density) discharge. The discharge behavior is characterized using terminal current-voltage-characteristics, microwave interferometer measurements, and plasma emission intensity measurements. Numerous spectroscopic measurements of O2(a1Delta), oxygen atoms, and discharge excited states are made in order to describe the discharge performance dependent on various parameters. The influence of NO on O-atom flow rates and O2(a1Delta) production is investigated. Progress of laser power extraction since initial reports in 2005 is overviewed.

Coupling mechanism of electric vehicle and grid under the background of smart grid

NASA Astrophysics Data System (ADS)

Dong, Mingyu; Li, Dezhi; Chen, Rongjun; Shu, Han; He, Yongxiu

2018-02-01

With the development of smart distribution technology in the future, electric vehicle users can not only charge reasonably based on peak-valley price, they can also discharge electricity into the power grid to realize their economic benefit when it’s necessary and thus promote peak load shifting. According to the characteristic that future electric vehicles can discharge, this paper studies the interaction effect between electric vehicles and the grid based on TOU (time of use) Price Strategy. In this paper, four scenarios are used to compare the change of grid load after implementing TOU Price Strategy. The results show that the wide access of electric vehicles can effectively reduce peak and valley difference.

Research on charging and discharging control strategy for electric vehicles as distributed energy storage devices

NASA Astrophysics Data System (ADS)

Zhang, Min; Yang, Feng; Zhang, Dongqing; Tang, Pengcheng

2018-02-01

A large number of electric vehicles are connected to the family micro grid will affect the operation safety of the power grid and the quality of power. Considering the factors of family micro grid price and electric vehicle as a distributed energy storage device, a two stage optimization model is established, and the improved discrete binary particle swarm optimization algorithm is used to optimize the parameters in the model. The proposed control strategy of electric vehicle charging and discharging is of practical significance for the rational control of electric vehicle as a distributed energy storage device and electric vehicle participating in the peak load regulation of power consumption.

Fundamental experiment of ion thruster using ECR discharge

NASA Astrophysics Data System (ADS)

Yasui, Toshiaki; Kitayama, Jiro; Tahara, Hirokazu; Onoe, Ken-Ichi; Yoshikawa, Takao

A microwave ion thruster has the potential to overcome a lifetime problem of electric propulsion by eliminating electrodes. Two types of microwave ion thruster have been investigated to examine the operational characteristics. The one is the thruster using cavity-resonance microwave discharge, and the other is the thruster using Electron Cyclotron Resonance (ECR) discharge. Cavity-resonance microwave discharge produced plasmas by strong electric field in the resonant cavity and sustained plasmas at argon mass flow rates above 10 sccm. However, ECR discharge was capable of sustaining plasmas at lower mass flow rate, because ECR discharge efficiently produced plasmas by resonance absorption. From these generated microwave plasmas, ions were electrostatically extracted by two multiaperture grids. In ECR discharge, the maximum ion beam current of 75 mA and the highest mass utilization efficiency of 18.7% were achieved at a total extraction voltage of 950 V.

Microelectrode-assisted low-voltage atmospheric pressure glow discharge in air

NASA Astrophysics Data System (ADS)

Liu, Wenzheng; Zhao, Shuai; Niu, Jiangqi; Chai, Maolin

2017-09-01

During the process of discharge, appropriately changing the paths corresponding to electric field lines and the field strength distribution along these paths, as well as increasing the number of initial electrons, can effectively enhance the uniformity of discharge and inhibit the formation of filamentary discharge. A method is proposed that uses a microelectrode to initiate the macroscopic discharge phenomenon. An asymmetric structure was designed comprising a single electrode of carbon fiber; this electrode structure is of helical-contact type. Benefitting from the special electric field distribution and the microdischarge process, a three-dimensional atmospheric pressure glow discharge was achieved in air, characterized by low discharge voltage, low energy consumption, good diffusion performance, and less ozone generation. The plasma studied is uniform and stable with good diffusion characteristics and low levels of contaminants and hence has potential applications in the field of air purification.

Behavior of Combined Dielectric-Metallic Systems in a Charged Particle Environment

NASA Technical Reports Server (NTRS)

Gordon, W. L.; Hoffman, R. W.

1984-01-01

The charging and discharging characteristics of an electrically isolated solar array segment were studied in order to simulate discharges seen during geomagnetic substorms. A solar array segment was floated while bombarded with monoenergetic electrons at various angles of incidence. The potentials of the array surface and of the interconnects were monitored using Trek voltage probes to maintain electrical isolation. A back plate was capacitively coupled to the array to provide information on the characteristics of the transients accompanying the discharges. Several modes of discharging of the array were observed at relatively low differential and absolute potentials (a few kilovolts). A relatively slow discharge response in the array was observed, discharging over one second with currents of nanoamps. Two types of faster discharges were also seen which lasted a few hundredths of a millisecond and with currents on the order of microamps. Some results indicate an electron emission process associated with the arcs.

Percolation simulation of laser-guided electrical discharges.

PubMed

Sasaki, Akira; Kishimoto, Yasuaki; Takahashi, Eiichi; Kato, Susumu; Fujii, Takashi; Kanazawa, Seiji

2010-08-13

A three-dimensional simulation of laser-guided discharges based on percolation is presented. The model includes both local growth of a streamer due to the enhanced electric field at the streamer's tip and propagation of a leader by remote ionization such as that caused by runaway electrons. The stochastic behavior of the discharge through a preformed plasma channel is reproduced by the calculation, which shows complex path with detouring and bifurcation. The probability of guiding is investigated with respect to the ionized, conductive fraction along the channel.

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

NASA Astrophysics Data System (ADS)

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).

Analysis on the spectra and synchronous radiated electric field observation of cloud-to-ground lightning discharge plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cen Jianyong; Yuan Ping; Qu Haiyan

2011-11-15

According to the spectra of cloud-to-ground (CG) lightning discharge plasma captured by a slit-less spectrograph and the information of synchronous radiated electric field, the temperatures, the total intensity of spectra, the peak value of current and its action integral of discharge plasma channel have been calculated. Furthermore, the correlativity of these parameters has been analyzed for the first time. The results indicate that the total intensity of spectra has a positive correlation to the discharge current in different strokes of one CG lightning, and the temperature of discharge plasma is direct proportion to the action integral in the first returnmore » strokes of different lightning.« less

The New NASA-STD-4005 and NASA-HDBK-4006, Essentials for Direct-Drive Solar Electric Propulsion

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.

2007-01-01

High voltage solar arrays are necessary for direct-drive solar electric propulsion, which has many advantages, including simplicity and high efficiency. Even when direct-drive is not used, the use of high voltage solar arrays leads to power transmission and conversion efficiencies in electric propulsion Power Management and Distribution. Nevertheless, high voltage solar arrays may lead to temporary power disruptions, through the so-called primary electrostatic discharges, and may permanently damage arrays, through the so-called permanent sustained discharges between array strings. Design guidance is needed to prevent these solar array discharges, and to prevent high power drains through coupling between the electric propulsion devices and the high voltage solar arrays. While most electric propulsion systems may operate outside of Low Earth Orbit, the plasmas produced by their thrusters may interact with the high voltage solar arrays in many ways similarly to Low Earth Orbit plasmas. A brief description of previous experiences with high voltage electric propulsion systems will be given in this paper. There are two new official NASA documents available free through the NASA Standards website to help in designing and testing high voltage solar arrays for electric propulsion. They are NASA-STD-4005, the Low Earth Orbit Spacecraft Charging Design Standard, and NASA-HDBK-4006, the Low Earth Orbit Spacecraft Charging Design Handbook. Taken together, they can both educate the high voltage array designer in the engineering and science of spacecraft charging in the presence of dense plasmas and provide techniques for designing and testing high voltage solar arrays to prevent electrical discharges and power drains.

Study of SF6 gas decomposition products based on spectroscopy technology

NASA Astrophysics Data System (ADS)

Cai, Ji-xing; Na, Yan-xiang; Ni, Wei-yuan; Li, Guo-wei; Feng, Ke-cheng; Song, Gui-cai

2011-08-01

With the rapid development of power industry, the number of SF6 electrical equipment are increasing, it has gradually replaced the traditional insulating oil material as insulation and arc media in the high-voltage electrical equipment. Pure SF6 gas has excellent insulating properties and arc characteristics; however, under the effect of the strong arc, SF6 gas will decompose and generate toxic substances, then corroding electrical equipment, thereby affecting the insulation and arc ability of electrical equipment. If excessive levels of impurities in the gas that will seriously affect the mechanical properties, breaking performance and electrical performance of electrical equipment, it will cause many serious consequences, even threaten the safe operation of the grid. This paper main analyzes the basic properties of SF6 gas and the basic situation of decomposition in the discharge conditions, in order to simulate the actual high-voltage electrical equipment, designed and produced a simulation device that can simulate the decomposition of SF6 gas under a high voltage discharge, and using fourier transform infrared spectroscopy to analyze the sample that produced by the simulation device. The result show that the main discharge decomposition product is SO2F2 (sulfuryl fluoride), the substance can react with water and generate corrosive H2SO4(sulfuric acid) and HF (hydrogen fluoride), also found that the increase in the number with the discharge, SO2F2concentration levels are on the rise. Therefore, the material can be used as one of the main characteristic gases to determine the SF6 electrical equipment failure, and to monitor their concentration levels.

High Voltage Discharge Profile on Soil Breakdown Using Impulse Discharge

NASA Astrophysics Data System (ADS)

Fajingbesi, F. E.; Midi, N. S.; Elsheikh, E. M. A.; Yusoff, S. H.

2017-06-01

Grounding terminals are mandatory in electrical appliance design as they provide safety route during overvoltage faults. The soil (earth) been the universal ground is assumed to be at zero electric potential. However, due to properties like moisture, pH and available nutrients; the electric potential may fluctuate between positive and negative values that could be harmful for internally connected circuits on the grounding terminal. Fluctuations in soil properties may also lead to current crowding effect similar to those seen at the emitters of semiconductor transistors. In this work, soil samples are subjected to high impulse voltage discharge and the breakdown characteristics was profiled. The results from profiling discharge characteristics of soil in this work will contribute to the optimization of grounding protection system design in terms of electrode placement. This would also contribute to avoiding grounding electrode current crowding, ground potential rise fault and electromagnetic coupling faults.

Traveling wire electrode increases productivity of Electrical Discharge Machining /EDM/ equipment

NASA Technical Reports Server (NTRS)

Kotora, J., Jr.; Smith, S. V.

1967-01-01

Traveling wire electrode on electrical discharge machining /EDM/ equipment reduces the time requirements for precision cutting. This device enables cutting with a minimum of lost material and without inducing stress beyond that inherent in the material. The use of wire increases accuracy and enables tighter tolerances to be maintained.

46 CFR 129.540 - Remote stopping-systems on OSVs of 100 or more gross tons.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Miscellaneous Electrical Systems § 129.540 Remote stopping... subpart 111.103 of this chapter: (1) For each propulsion unit, in the pilothouse. (2) For each discharge pump for bilge slop or dirty oil, at the deck discharge. (3) For each powered ventilation system...

Study of a DC gas discharge with a copper cathode in a water flow

NASA Astrophysics Data System (ADS)

Tazmeev, G. Kh.; Timerkaev, B. A.; Tazmeev, Kh. K.

2017-07-01

A dc gas discharge between copper electrodes in the current range of 5-20 A was studied experimentally. The discharge gap length was varied within 45-70 mm. The cathode was a 10-mm-diameter rod placed in the water flowing out from a dielectric tube. Three discharge configurations differing in the position of the cathode upper end with respect to the water surface were considered: (i) above water; (ii) flush with the water surface, and (iii) under water. The electric and optical characteristics of the discharge in the second configuration were studied in more detail. It is established that the discharge properties are similar to those of an electric arc. Considerable cathode erosion was observed in the third configuration. It is revealed that fine-dispersed copper grains form in the course of erosion.

Nonthermal Biological Treatments Using Discharge Plasma Produced by Pulsed Power 4. Cleaning of Lakes and Marshes by Pulsed Power Produced Streamer Discharges in Water

NASA Astrophysics Data System (ADS)

Akiyama, Hidenori; Katsuki, Sunao; Namihira, Takao; Ishibashi, Kazuo; Kiyosaki, Noriaki

Pulsed power has been used to produce non-thermal plasmas in atmospheric pressure gases that generate a high electric field at the tips of streamer discharges, where high energy electrons, free radicals, ultraviolet rays, and ozone are produced. These manifestations of streamer discharges have been used in the treatment of exhaust gases, removal of volatile and toxic compounds such as dioxin, and the sterilization of microorganisms. Here, large volume streamer discharges in water are described. These streamer discharges in liquids are able to produce a high electric field, high energy electrons, ozone, chemically active species, ultraviolet rays, and shock waves, which readily sterilize microorganisms and decompose molecules and materials. An application of this phenomenon to the cleaning of lakes and marshes is also described.

The electrical characteristics of the dielectric barrier discharges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yehia, Ashraf, E-mail: yehia30161@yahoo.com; Department of Physics, Faculty of Science, Assiut University, Assiut 71516

2016-06-15

The electrical characteristics of the dielectric barrier discharges have been studied in this paper under different operating conditions. The dielectric barrier discharges were formed inside two reactors composed of electrodes in the shape of two parallel plates. The dielectric layers inside these reactors were pasted on the surface of one electrode only in the first reactor and on the surfaces of the two electrodes in the second reactor. The reactor under study has been fed by atmospheric air that flowed inside it with a constant rate at the normal temperature and pressure, in parallel with applying a sinusoidal ac voltagemore » between the electrodes of the reactor. The amount of the electric charge that flows from the reactors to the external circuit has been studied experimentally versus the ac peak voltage applied to them. An analytical model has been obtained for calculating the electrical characteristics of the dielectric barrier discharges that were formed inside the reactors during a complete cycle of the ac voltage. The results that were calculated by using this model have agreed well with the experimental results under the different operating conditions.« less

Laboratory facility for testing electric-vehicle batteries Test rig for simulating duty cycles with different discharge modes

NASA Astrophysics Data System (ADS)

Hamilton, J. A.; Rand, D. A. J.

1983-03-01

A test rig has been designed and constructed to examine the performance of batteries under laboratory conditions that simulate the power characteristics of electric vehicles. Each station in the rig subjects a battery to continuous charge/discharge cycles, with an equalising charge every eighth cycle. The battery discharge follows the current-verse-time profile of a given vehicle operating under a driving schedule normal to road service. The test rig allows both smooth- and pulsed-current discharge to be investigated. Data collection is accomplished either with multi-pen recorders or with a computer-based information logger.

Development of electrical test procedures for qualification of spacecraft against EID. Volume 1: The CAN test and other relevant data

NASA Technical Reports Server (NTRS)

Wilkenfeld, J. M.; Judge, R. J. R.; Harlacher, B. L.

1982-01-01

A combined experimental and analytical program to develop system electrical test procedures for the qualification of spacecraft against damage produced by space-electron-induced discharges (EID) occurring on spacecraft dielectric outer surfaces is described. The data on the response of a simple satellite model, called CAN, to electron-induced discharges is presented. The experimental results were compared to predicted behavior and to the response of the CAN to electrical injection techniques simulating blowoff and arc discharges. Also included is a review of significant results from other ground tests and the P78-2 program to form a data base from which is specified those test procedures which optimally simulate the response of spacecraft to EID. The electrical and electron spraying test data were evaluated to provide a first-cut determination of the best methods for performance of electrical excitation qualification tests from the point of view of simulation fidelity.

Computational Interpretation of the Relation Between Electric Field and the Applied Current for Cathodic Protection Under Different Conductivity Environments

NASA Astrophysics Data System (ADS)

Kim, Yong-Sang; Ko, Sang-Jin; Lee, Sangkyu; Kim, Jung-Gu

2018-03-01

An interpretation of the relation between the electric field and the applied current for cathodic protection is investigated using a boundary element method simulation. Also, a conductivity-difference environment is set for the interface influence. The variation of the potential distribution is increased with the increase of the applied current and the conductivity difference due to the rejection of the current at the interface. In the case of the electric field, the tendencies of the increasing rate and the applied currents are similar, but the interface influence is different according to the directional component and field type (decrease of E z and increases of E x and E y) due to the directional difference between the electric fields. Also, the change tendencies of the electric fields versus the applied current plots are affected by the polarization curve tendency regarding the polarization type (activation and concentration polarizations in the oxygen-reduction and hydrogen-reduction reactions). This study shows that the underwater electric signature is determined by the polarization behavior of the materials.

40 CFR 63.543 - Standards for process sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (a) No owner or operator of a secondary lead smelter shall discharge or cause to be discharged into the atmosphere from any existing, new, or reconstructed blast, reverberatory, rotary, or electric... discharge or cause to be discharged into the atmosphere from any existing, new, or reconstructed blast...

A new technique for robot vision in autonomous underwater vehicles using the color shift in underwater imaging

DTIC Science & Technology

2017-06-01

FOR ROBOT VISION IN AUTONOMOUS UNDERWATER VEHICLES USING THE COLOR SHIFT IN UNDERWATER IMAGING by Jake A. Jones June 2017 Thesis Advisor...June 2017 3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE A NEW TECHNIQUE FOR ROBOT VISION IN AUTONOMOUS UNDERWATER...Developing a technique for underwater robot vision is a key factor in establishing autonomy in underwater vehicles. A new technique is developed and

Consumption of the electric power inside silent discharge reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yehia, Ashraf, E-mail: yehia30161@yahoo.com

An experimental study was made in this paper to investigate the relation between the places of the dielectric barriers, which cover the surfaces of the electrodes in the coaxial cylindrical reactors, and the rate of change of the electric power that is consumed in forming silent discharges. Therefore, silent discharges have been formed inside three coaxial cylindrical reactors. The dielectric barriers in these reactors were pasted on both the internal surface of the outer electrode in the first reactor and the external surface of the inner electrode in the second reactor as well as the surfaces of the two electrodesmore » in the third reactor. The reactor under study has been fed by atmospheric air that flowed inside it with a constant rate at normal temperature and pressure, in parallel with the application of a sinusoidal ac voltage between the electrodes of the reactor. The electric power consumed in forming the silent discharges inside the three reactors was measured as a function of the ac peak voltage. The validity of the experimental results was investigated by applying Manley's equation on the same discharge conditions. The results have shown that the rate of consumption of the electric power relative to the ac peak voltage per unit width of the discharge gap improves by a ratio of either 26.8% or 80% or 128% depending on the places of the dielectric barriers that cover the surfaces of the electrodes inside the three reactors.« less

Phase-locking behavior in a high-frequency gymnotiform weakly electric fish, Adontosternarchus.

PubMed

Kawasaki, Masashi; Leonard, John

2017-02-01

An apteronotid weakly electric fish, Adontosternarchus, emits high-frequency electric organ discharges (700-1500 Hz) which are stable in frequency if no other fish or artificial signals are present. When encountered with an artificial signal of higher frequency than the fish's discharge, the fish raised its discharge frequency and eventually matched its own frequency to that of the artificial signal. At this moment, phase locking was observed, where the timing of the fish's discharge was precisely stabilized at a particular phase of the artificial signal over a long period of time (up to minutes) with microsecond precision. Analyses of the phase-locking behaviors revealed that the phase values of the artificial stimulus at which the fish stabilizes the phase of its own discharge (called lock-in phases) have three populations between -180° and +180°. During the frequency rise and the phase-locking behavior, the electrosensory system is exposed to the mixture of feedback signals from its electric organ discharges and the artificial signal. Since the signal mixture modulates in both amplitude and phase, we explored whether amplitude or phase information participated in driving the phase-locking behavior, using a numerical model. The model which incorporates only amplitude information well predicted the three populations of lock-in phases. When phase information was removed from the electrosensory stimulus, phase-locking behavior was still observed. These results suggest that phase-locking behavior of Adontosternarchus requires amplitude information but not phase information available in the electrosensory stimulus.

Particle-in-Cell Simulations of the Twisted Magnetospheres of Magnetars. I.

NASA Astrophysics Data System (ADS)

Chen, Alexander Y.; Beloborodov, Andrei M.

2017-08-01

The magnetospheres of magnetars are believed to be filled with electron-positron plasma generated by electric discharge. We present a first numerical experiment demonstrating this process in an axisymmetric magnetosphere with a simple threshold prescription for pair creation, which is applicable to the inner magnetosphere with an ultrastrong field. The {e}+/- discharge occurs in response to the twisting of the closed magnetic field lines by a shear deformation of the magnetar surface, which launches electric currents into the magnetosphere. The simulation shows the formation of an electric “gap” with an unscreened electric field ({\\boldsymbol{E}}\\cdot {\\boldsymbol{B}}\

TSS-1R Failure Mode Evaluation

NASA Technical Reports Server (NTRS)

Vaughn, Jason A.; McCollum, Matthew B.; Kamenetzky, Rachel R.

1997-01-01

Soon after the break of the tether during the Tethered Satellite System (TSS-1R) mission in February, 1996, a Tiger Team was assembled at the George C. Marshall Space Flight Center to determine the tether failure mode. One possible failure scenario was the Kevlar' strength member of the tether failed because of degradation due to electrical discharge or electrical arcing. During the next several weeks, extensive electrical discharge testing in low vacuum and plasma environments was conducted in an attempt to reproduce the electrical activity recorded by on-board science instruments during the mission. The results of these tests are presented in this paper.

High Discharge Energy Density at Low Electric Field Using an Aligned Titanium Dioxide/Lead Zirconate Titanate Nanowire Array

PubMed Central

Zhang, Dou; Liu, Weiwei; Guo, Ru; Zhou, Kechao

2017-01-01

Abstract Polymer‐based capacitors with high energy density have attracted significant attention in recent years due to their wide range of potential applications in electronic devices. However, the obtained high energy density is predominantly dependent on high applied electric field, e.g., 400–600 kV mm−1, which may bring more challenges relating to the failure probability. Here, a simple two‐step method for synthesizing titanium dioxide/lead zirconate titanate nanowire arrays is exploited and a demonstration of their ability to achieve high discharge energy density capacitors for low operating voltage applications is provided. A high discharge energy density of 6.9 J cm−3 is achieved at low electric fields, i.e., 143 kV mm−1, which is attributed to the high relative permittivity of 218.9 at 1 kHz and high polarization of 23.35 µC cm−2 at this electric field. The discharge energy density obtained in this work is the highest known for a ceramic/polymer nanocomposite at such a low electric field. The novel nanowire arrays used in this work are applicable to a wide range of fields, such as energy harvesting, energy storage, and photocatalysis. PMID:29610724

AC Glow Discharge Plasma in N2O

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yousif, F. B.; Martinez, H.; Robledo-Martinez, A.

2006-12-04

This paper considers the optical and electrical characterization of AC glow discharge plasma in the abnormal glow mode used for optical emission spectroscopy. The total discharge current and applied voltage are measured using conventional techniques. The electrical characteristics of the planer-cathode glow discharge confirmed that the plasma is operating at abnormal discharge mode characterized by the increases in the operating voltage as the current was raised under given pressure. Optical emission spectroscopy was used to determine the main emission lines of the glow discharge plasma of N2O at pressures between 0.5 and 4.0 Torr. It shows that the discharge emissionmore » range is mainly within 300-400 nm. The emission lines correspond to NO, O2, and O{sub 2}{sup +} are the dominant lines in the glow discharge plasma in the present study. Intensity of the emission lines show linear increase with the discharge current up to 0.4 A followed by saturation at higher currents. No emission lines were observed in this work corresponding to atomic oxygen or nitrogen.« less

A Comparison of Inductive Sensors in the Characterization of Partial Discharges and Electrical Noise Using the Chromatic Technique.

PubMed

Ardila-Rey, Jorge Alfredo; Montaña, Johny; de Castro, Bruno Albuquerque; Schurch, Roger; Covolan Ulson, José Alfredo; Muhammad-Sukki, Firdaus; Bani, Nurul Aini

2018-03-29

Partial discharges (PDs) are one of the most important classes of ageing processes that occur within electrical insulation. PD detection is a standardized technique to qualify the state of the insulation in electric assets such as machines and power cables. Generally, the classical phase-resolved partial discharge (PRPD) patterns are used to perform the identification of the type of PD source when they are related to a specific degradation process and when the electrical noise level is low compared to the magnitudes of the PD signals. However, in practical applications such as measurements carried out in the field or in industrial environments, several PD sources and large noise signals are usually present simultaneously. In this study, three different inductive sensors have been used to evaluate and compare their performance in the detection and separation of multiple PD sources by applying the chromatic technique to each of the measured signals.

Electrical and optical properties of Ar/NH{sub 3} atmospheric pressure plasma jet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Zheng-Shi, E-mail: changzhsh1984@163.com, E-mail: gjzhang@xjtu.edu.cn; Yao, Cong-Wei; Chen, Si-Le

Inspired by the Penning effect, we obtain a glow-like plasma jet by mixing ammonia (NH{sub 3}) into argon (Ar) gas under atmospheric pressure. The basic electrical and optical properties of an atmospheric pressure plasma jet (APPJ) are investigated. It can be seen that the discharge mode transforms from filamentary to glow-like when a little ammonia is added into the pure argon. The electrical and optical analyses contribute to the explanation of this phenomenon. The discharge mode, power, and current density are analyzed to understand the electrical behavior of the APPJ. Meanwhile, the discharge images, APPJ's length, and the components ofmore » plasma are also obtained to express its optical characteristics. Finally, we diagnose several parameters, such as gas temperature, electron temperature, and density, as well as the density number of metastable argon atoms of Ar/NH{sub 3} APPJ to help judge the usability in its applications.« less

An investigation of the reduction of carbon dioxide in a silent electric discharge

NASA Technical Reports Server (NTRS)

Luce, R. S.; Greenough, B. (Editor)

1978-01-01

The reduction of CO2 to O2 and CO in a silent electric discharge was studied. It was found that current alone (in the ionized plasma induced by the silent electric discharge) was reponsible for the CO2 reduction process. Voltage and frequency were important only in so far as they induced current in the plasma. Pressure and temperature were of minimum influence in the process. The large power consumption in the process was recognized as resulting from the low power factor of the reactor vessel which electrically behaved like a capacitor. The power factor was subsequently improved by adding an inductive element to make the reactor vessel capacitance part of a resonant circuit. It was found that the CO2 reduction process was most efficient in terms of power vs reduction rate when a voltage was employed that was only slightly higher than that needed to induce the plasma.

Reaction of Cl- ions in electrolyte solution induced electrical discharge plasma in the presence of argon fine bubbles

NASA Astrophysics Data System (ADS)

Hayashi, Yui; Takada, Noriharu; Wahyudiono, Kanda, Hideki; Goto, Motonobu

2017-05-01

Active chlorine species such as chlorine molecules and hypochlorous acid have been known as high performance sanitizers. They would act more reactive on chemical and biological substances when an electrical discharge was introduced in water containing an electrolyte substance. Here, the reaction of chloride (Cl-) ions were examined by introducing of a pulsed discharge plasma in sodium chloride (NaCl) solution as an electrolyte solution at room temperature. The results show that a large electrical current generated by the pulsed discharge plasma affected the reaction of Cl- ions to result available chlorine. The reaction pathway for available chlorine production was assumed similar with the reaction pathway as electrolysis. A pulsed discharge plasma in NaCl solution in the presence of argon (Ar) fine bubbles exhibited intense emissions and high electron density compared to when no Ar fine bubbles were introduced. At these conditions, the dissociation reaction rate of water increased drastically leads to the formation of 0 atoms. As a result, the reaction of Cl- ions and the available chlorine generation were also increased.

Stark effect of Ar I lines for electric field strength diagnostics in the cathode sheath of glow discharge

NASA Astrophysics Data System (ADS)

Vasiljević, Milica M.; Spasojević, Djordje; Šišović, Nikola M.; Konjević, Nikola

2017-09-01

We present a study of argon glow discharge which shows that measured wavenumber DC Stark shifts Δ ν of two neutral argon lines, Ar I 518.75 nm and Ar I 522.127 nm, can be used for reliable determination of the electric field strength F distribution in the cathode sheath region of the discharge. In order to experimentally determine the coefficient c in quadratic correlation Δ ν =cF2 , manifested in a low field range (up to 15 kV/cm), the discharge is seeded with a small admixture of hydrogen, and the values of F are measured via Stark polarization spectroscopy of the hydrogen Balmer beta line. Once known, this can be used for the determination of F by a simple and inexpensive spectroscopic Stark shift measurement in discharges with other argon admixtures or pure argon. Reported shift results are in good agreement with data extrapolated from measurements performed at high electric fields (over 100 kV/cm) by Windholz (Phys. Scr., 21 (1980) 67).

Optical and electrical characteristics of hollow-needle to plate atmospheric-pressure discharge in nitrogen

NASA Astrophysics Data System (ADS)

Simek, Milan; Schmidt, Jiri; Pekarek, Stanislav; Khun, Josef

2006-10-01

We have studied basic optical and electrical characteristics of the DC hollow needle to plate electrical discharge enhanced by the gas flow through the needle. Substantial advantage of this arrangement is that all gas supplied to the discharge passes through the discharge zone and therefore it is affected by plasma chemical processes. Depending on the energy dissipated between electrodes, we previously observed two basic discharge regimes: a) DC corona and b) DC corona superimposed with pulsed filamentary streamers [1]. In this work, we have analyzed radiation induced by filamentary streamers. In addition to nitrogen emissions driven by electron impact processes we have detected emission induced by specific energy transfer processes [2]. We have also determined mean repetition frequency of filamentary streamers (0.1-15 kHz) for the needle-to-plane gap and for the nitrogen flow through the needle ranging between 2-6 mm and 1-10 slm, respectively. [1] M. Simek and S.Pekarek, GEC 2005, Bul. Am. Phys. Soc. 50, 29, (2005) ; [2] M. Simek at al, Pure Appl. Chem. 78, 1213, (2006).

Reversible switch between underwater superaerophilicity and superaerophobicity on the superhydrophobic nanowire-haired mesh for controlling underwater bubble wettability

NASA Astrophysics Data System (ADS)

Shan, Chao; Yong, Jiale; Yang, Qing; Chen, Feng; Huo, Jinglan; Zhuang, Jian; Jiang, Zhuangde; Hou, Xun

2018-04-01

Controlling the underwater bubble wettability on a solid surface is of great research significance. In this letter, a simple method to achieve reversible switch between underwater superaerophilicity and underwater superaerophobicity on a superhydrophobic nanowire-haired mesh by alternately vacuumizing treatment in water and drying in air is reported. Such reversible switch endows the as-prepared mesh with many functional applications in controlling bubble's behavior on a solid substrate. The underwater superaerophilic mesh is able to absorb/capture bubbles in water, while the superaerophobic mesh has great anti-bubble ability. The reversible switch between underwater superaerophilicity and superaerophobicity can selectively allow bubbles to go through the resultant mesh; that is, bubbles can pass through the underwater superaerophilic mesh while are fully intercepted by the underwater superaerophobic mesh in a water medium. We believe these meshes will have important applications in removing or capturing underwater bubbles/gas.

Underwater Turbulence Detection Using Gated Wavefront Sensing Technique

PubMed Central

Bi, Ying; Xu, Xiping; Chow, Eddy Mun Tik

2018-01-01

Laser sensing has been applied in various underwater applications, ranging from underwater detection to laser underwater communications. However, there are several great challenges when profiling underwater turbulence effects. Underwater detection is greatly affected by the turbulence effect, where the acquired image suffers excessive noise, blurring, and deformation. In this paper, we propose a novel underwater turbulence detection method based on a gated wavefront sensing technique. First, we elaborate on the operating principle of gated wavefront sensing and wavefront reconstruction. We then setup an experimental system in order to validate the feasibility of our proposed method. The effect of underwater turbulence on detection is examined at different distances, and under different turbulence levels. The experimental results obtained from our gated wavefront sensing system indicate that underwater turbulence can be detected and analyzed. The proposed gated wavefront sensing system has the advantage of a simple structure and high detection efficiency for underwater environments. PMID:29518889

Novel high power impulse magnetron sputtering enhanced by an auxiliary electrical field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Chunwei, E-mail: lcwnefu@126.com, E-mail: xiubotian@163.com; State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001; Tian, Xiubo, E-mail: lcwnefu@126.com, E-mail: xiubotian@163.com

2016-08-15

The high power impulse magnetron sputtering (HIPIMS) technique is a novel highly ionized physical vapor deposition method with a high application potential. However, the electron utilization efficiency during sputtering is rather low and the metal particle ionization rate needs to be considerably improved to allow for a large-scale industrial application. Therefore, we enhanced the HIPIMS technique by simultaneously applying an electric field (EF-HIPIMS). The effect of the electric field on the discharge process was studied using a current sensor and an optical emission spectrometer. Furthermore, the spatial distribution of the electric potential and electric field during the EF-HIPIMS process wasmore » simulated using the ANSYS software. The results indicate that a higher electron utilization efficiency and a higher particle ionization rate could be achieved. The auxiliary anode obviously changed the distribution of the electric potential and the electric field in the discharge region, which increased the plasma density and enhanced the degree of ionization of the vanadium and argon gas. Vanadium films were deposited to further compare both techniques, and the morphology of the prepared films was investigated by scanning electron microscopy. The films showed a smaller crystal grain size and a denser growth structure when the electric field was applied during the discharge process.« less

Dielectric gas mixtures containing sulfur hexafluoride

DOEpatents

Cooke, Chathan M.

1979-01-01

Electrically insulating gaseous media of unexpectedly high dielectric strength comprised of mixtures of two or more dielectric gases are disclosed wherein the dielectric strength of at least one gas in each mixture increases at less than a linear rate with increasing pressure and the mixture gases are present in such proportions that the sum of their electrical discharge voltages at their respective partial pressures exceeds the electrical discharge voltage of each individual gas at the same temperature and pressure as that of the mixture.

Utilizing Four Dimensional Lightning and Dual-Polarization Radar to Develop Lightning Initiation Forecast Guidance

DTIC Science & Technology

2015-03-26

Electrification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3 Lightning Discharge ...charge is caused by falling graupel that is positively charged (Wallace and Hobbs 2006). 2.3 Lightning Discharge Lightning occurs when the electric...emission of positive corona from the surface of precipitation particles, causing the electric field to become locally enhanced and supporting the

Electric discharge effects on a XeCl pumped S2 heat-pipe laser

NASA Technical Reports Server (NTRS)

Killeen, K.; Greenberg, K.; Verdeyen, J. T.

1982-01-01

It is shown that an electrical discharge can dissociate the higher-order sulfur molecules S(3-8) into dimers S2 and thus create the proper environment for efficient conversion of XeCl radiation at 308 nm to the blue-green. The use of a heat-pipe configuration greatly alleviates the technological problems.

Characteristics of return stroke electric fields produced by lightning flashes at distances of 1 to 15 kilometers

NASA Technical Reports Server (NTRS)

Hopf, CH.

1991-01-01

Electric field derivative signals from single and multiple lightning strokes are presented. For about 25 pct. of all acquired waveforms, produced by return strokes, stepped leaders or intracloud discharges, type and distance of the signal source are known from the observations by an all sky video camera system. The analysis of the electric field derivative waveforms in the time domain shows a significant difference in the impulse width between return stroke signals and those of stepped leaders and intracloud discharges. In addition, the computed amplitude density spectrum of return stroke waveforms lies by a factor of 10 above that of stepped leaders and intracloud discharges in the frequency range from 50 to 500 kHz.

Customized electric power storage device for inclusion in a collective microgrid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinett, III, Rush D.; Wilson, David G.; Goldsmith, Steven Y.

An electric power storage device is described herein, wherein the electric power storage device is included in a microgrid. The electric power storage device has at least one of a charge rate, a discharge rate, or a power retention capacity that has been customized for a collective microgrid. The collective microgrid includes at least two connected microgrids. The at least one of the charge rate, the discharge rate, or the power retention capacity of the electric power storage device is computed based at least in part upon specified power source parameters in the at least two connected microgrids and specifiedmore » load parameters in the at least two connected microgrids.« less

Characteristics and applications of diffuse discharge of water electrode in air

NASA Astrophysics Data System (ADS)

Wenzheng, LIU; Tahan, WANG; Xiaozhong, CHEN; Chuanlong, MA

2018-01-01

Plasma water treatment technology, which aims to produce strong oxidizing reactive particles that act on the gas-liquid interface by way of discharging, is used to treat the organic pollutants that do not degrade easily in water. This paper presents a diffuse-discharge plasma water treatment method, which is realized by constructing a conical air gap through an uneven medium layer. The proposed method uses water as one electrode, and a dielectric barrier discharge electrode is constructed by using an uneven dielectric. The electric field distribution in the discharge space will be uneven, wherein the long gap electric field will have a smaller intensity, while the short one will have a larger intensity. A diffuse glow discharge is formed in the cavity. With this type of plasma water treatment equipment, a methyl orange solution with a concentration of 10 mg l-1 was treated, and the removal rate was found to reach 88.96%.

N2O and CO production by electric discharge - Atmospheric implications. [Venus atmosphere simulation

NASA Technical Reports Server (NTRS)

Levine, J. S.; Howell, W. E.; Hughes, R. E.; Chameides, W. L.

1979-01-01

Enhanced levels of N2O and CO were measured in tropospheric air samples exposed to a 17,500-J laboratory discharge. These enhanced levels correspond to an N2O production rate of about 4 trillion molecules/J and a CO production rate of about 10 to the 14th molecules/J. The CO measurements suggest that the primary region of chemical production in the discharge is the shocked air surrounding the lightning channel, as opposed to the slower-cooling inner core. Additional experiments in a simulated Venus atmosphere (CO2 - 95%, N2 - 5%, at one atmosphere) indicate an enhancement of CO from less than 0.1 ppm prior to the laboratory discharge to more than 2000 ppm after the discharge. Comparison with theoretical calculations appears to confirm the ability of a shock-wave/thermochemical model to predict the rate of production of trace species by an electrical discharge.

Introduction to investigations of the negative corona and EHD flow in gaseous two-phase fluids

NASA Astrophysics Data System (ADS)

Jerzy, MIZERACZYK; Artur, BERENDT

2018-05-01

Research interests have recently been directed towards electrical discharges in multi-phase environments. Natural electrical discharges, such as lightning and coronas, occur in the Earth’s atmosphere, which is actually a mixture of gaseous phase (air) and suspended solid and liquid particulate matters (PMs). An example of an anthropogenic gaseous multi-phase environment is the flow of flue gas through electrostatic precipitators (ESPs), which are generally regarded as a mixture of a post-combustion gas with solid PM and microdroplets suspended in it. Electrical discharges in multi-phase environments, the knowledge of which is scarce, are becoming an attractive research subject, offering a wide variety of possible discharges and multi-phase environments to be studied. This paper is an introduction to electrical discharges in multi-phase environments. It is focused on DC negative coronas and accompanying electrohydrodynamic (EHD) flows in a gaseous two-phase fluid formed by air (a gaseous phase) and solid PM (a solid phase), run under laboratory conditions. The introduction is based on a review of the relevant literature. Two cases will be considered: the first case is of a gaseous two-phase fluid, initially motionless in a closed chamber before being subjected to a negative corona (with the needle-to-plate electrode arrangement), which afterwards induces an EHD flow in the chamber, and the second, of a gaseous two-phase fluid flowing transversely with respect to the needle-to-plate electrode axis along a chamber with a corona discharge running between the electrodes. This review-based introductory paper should be of interest to theoretical researchers and modellers in the field of negative corona discharges in single- or two-phase fluids, and for engineers who work on designing EHD devices (such as ESPs, EHD pumps, and smoke detectors).

Oxygen discharge and post-discharge kinetics experiments and modeling for the electric oxygen-iodine laser system.

PubMed

Palla, A D; Zimmerman, J W; Woodard, B S; Carroll, D L; Verdeyen, J T; Lim, T C; Solomon, W C

2007-07-26

Laser oscillation at 1315 nm on the I(2P1/2)-->I(2P3/2) transition of atomic iodine has been obtained by a near resonant energy transfer from O2(a1Delta) produced using a low-pressure oxygen/helium/nitric oxide discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited species adds levels of complexity to the singlet oxygen generator (SOG) kinetics which are not encountered in a classic purely chemical O2(a1Delta) generation system. The advanced model BLAZE-IV has been introduced to study the energy-transfer laser system dynamics and kinetics. Levels of singlet oxygen, oxygen atoms, and ozone are measured experimentally and compared with calculations. The new BLAZE-IV model is in reasonable agreement with O3, O atom, and gas temperature measurements but is under-predicting the increase in O2(a1Delta) concentration resulting from the presence of NO in the discharge and under-predicting the O2(b1Sigma) concentrations. A key conclusion is that the removal of oxygen atoms by NOX species leads to a significant increase in O2(a1Delta) concentrations downstream of the discharge in part via a recycling process; however, there are still some important processes related to the NOX discharge kinetics that are missing from the present modeling. Further, the removal of oxygen atoms dramatically inhibits the production of ozone in the downstream kinetics.

Underwater hydraulic shock shovel control system

NASA Astrophysics Data System (ADS)

Liu, He-Ping; Luo, A.-Ni; Xiao, Hai-Yan

2008-06-01

The control system determines the effectiveness of an underwater hydraulic shock shovel. This paper begins by analyzing the working principles of these shovels and explains the importance of their control systems. A new type of control system’s mathematical model was built and analyzed according to those principles. Since the initial control system’s response time could not fulfill the design requirements, a PID controller was added to the control system. System response time was still slower than required, so a neural network was added to nonlinearly regulate the proportional element, integral element and derivative element coefficients of the PID controller. After these improvements to the control system, system parameters fulfilled the design requirements. The working performance of electrically-controlled parts such as the rapidly moving high speed switch valve is largely determined by the control system. Normal control methods generally can’t satisfy a shovel’s requirements, so advanced and normal control methods were combined to improve the control system, bringing good results.

Zero-power autonomous buoyancy system controlled by microbial gas production

NASA Astrophysics Data System (ADS)

Wu, Peter K.; Fitzgerald, Lisa A.; Biffinger, Justin C.; Spargo, Barry J.; Houston, Brian H.; Bucaro, Joseph A.; Ringeisen, Bradley R.

2011-05-01

A zero-power ballast control system that could be used to float and submerge a device solely using a gas source was built and tested. This system could be used to convey sensors, data loggers, and communication devices necessary for water quality monitoring and other applications by periodically maneuvering up and down a water column. Operational parameters for the system such as duration of the submerged and buoyant states can be varied according to its design. The gas source can be of any origin, e.g., compressed air, underwater gas vent, gas produced by microbes, etc. The zero-power ballast system was initially tested using a gas pump and further tested using gas produced by Clostridium acetobutylicum. Using microbial gas production as the only source of gas and no electrical power during operation, the system successfully floated and submerged periodically with a period of 30 min for at least 24 h. Together with microbial fuel cells, this system opens up possibilities for underwater monitoring systems that could function indefinitely.

Development of underwater cutting system by abrasive water-jet

NASA Astrophysics Data System (ADS)

Demura, Kenji; Yamaguchi, Hitoshi

1993-09-01

The technology to cut objects in the ocean's depths with abrasive water jets was examined for possible application in view of the greater water depths and sophistication involved in work on the ocean floor today. A test model was developed to study this technology's safety and practicability. The test model was designed for use at great water depths and has functions and a configuration that are unlike equipment used on land. A continuous, stable supply of abrasive is a distinctive design feature. In land applications, there had been problems with plugged tubes and an uneven supply. For this reason, the abrasive was converted to slurry form, and a continuous pressurized tube pump system was adopted for supply to the nozzle head. Also, a hydraulic motor that does not employ oil or electric power was used to provide an underwater drive that is environment-friendly. The report outlines the technology's general design concept including its distinctive functions and its configuration for use at great depths, and the report provides great detail on the equipment.

Investigating Discharge Ignition Fundamentals of Micro-Cathode Arc Thrusters

NASA Astrophysics Data System (ADS)

Teel, George Lewis

This dissertation is a compilation of studies of the volatile process that vacuum arcs undergo, known as breakdown. Breakdown is a transfer of electrons from one electrode to another. These electrons typically bombard the electrode surfaces causing secondary electron emission and ionization. This expulsion of ions and electrons then proceed to cause arc discharge, is what most people associate as ``the spark.'' This field-emission to breakdown process induces localized heating, which then causes this explosive ionization to occur. Once plasma is formed, high temperatures and pressures are forced on the surrounding surfaces. This initiation process, the effects of this process, and the manipulation of these effects have all been studied and described in this work. A series of initial observations of the before and after effects of discharge have been made through various equipment such as a Scanning Electron Microscope, Energy Dispersive X-Ray, and Confocal Microscope. Methods to develop a resistance measurement scheme provided a means to characterize the thruster's operation over its lifetime. Further characterization of the plasma plume was done through the use of Langmuir probes. Temperature and density distributions were also measured. An entirely new and miniaturized design of the thrusters were developed and initially tested. Last, a new application for these vacuum arc thrusters was studied for use in an underwater environment. The purpose of this work was to further develop a vacuum arc thruster, known as the Micro-Cathode Arc Thruster (muCAT), which has been developed at the George Washington University's Micro Propulsion and Nanotechnology Lab. The muCAT has been developed over the past decade, and in the last 5 years has gone from simple lab circuitry to space flown hardware. Therefore it is imperative to fully understand every aspect of this technology to achieve precisely what missions require. The results of this dissertation have allowed a new thruster concept to be developed, which is more robust and smaller than previous designed muCAT with erosion control built into the design. A new application for these vacuum arc thrusters has also been tested as underwater propulsion. This research has allowed us to come closer to a more perfected piece of propulsion technology.

Improving uniformity of atmospheric-pressure dielectric barrier discharges using dual frequency excitation

NASA Astrophysics Data System (ADS)

Liu, Y.; Peeters, F. J. J.; Starostin, S. A.; van de Sanden, M. C. M.; de Vries, H. W.

2018-01-01

This letter reports a novel approach to improve the uniformity of atmospheric-pressure dielectric barrier discharges using a dual-frequency excitation consisting of a low frequency (LF) at 200 kHz and a radio frequency (RF) at 13.56 MHz. It is shown that due to the periodic oscillation of the RF electric field, the electron acceleration and thus the gas ionization is temporally modulated, i.e. enhanced and suppressed during each RF cycle. As a result, the discharge development is slowed down with a lower amplitude and a longer duration of the LF discharge current. Hence, the RF electric field facilitates improved stability and uniformity simultaneously allowing a higher input power.

Numerical simulation of operation modes in atmospheric pressure uniform barrier discharge excited by a saw-tooth voltage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Xuechen; Niu Dongying; Yin Zengqian

2012-08-15

The characteristics of dielectric barrier discharge excited by a saw-tooth voltage are simulated in atmospheric pressure helium based on a one-dimensional fluid model. A stepped discharge is obtained per half voltage cycle with gas gap width less than 2 mm by the simulation, which is different to the pulsed discharge excited by a sinusoidal voltage. For the stepped discharge, the plateau duration increases with increasing the voltage amplitude and decreasing the gas gap. Therefore, uniform discharge with high temporal duty ratio can be realized with small gap through increasing the voltage amplitude. The maximal densities of both electron and ionmore » appear near the anode and the electric field is almost uniformly distributed along the gap, which indicates that the stepped discharge belongs to a Townsend mode. In contrast to the stepped discharge with small gas gap, a pulsed discharge can be obtained with large gas gap. Through analyzing the spatial density distributions of electron and ion and the electric field, the pulsed discharge is in a glow mode. The voltage-current (V-I) characteristics are analyzed for the above mentioned discharges under different gas gaps, from which the different discharge modes are verified.« less

Performance, Facility Pressure Effects, and Stability Characterization Tests of NASA's Hall Effect Rocket with Magnetic Shielding Thruster

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Yim, John; Herman, Daniel; Peterson, Peter Y.; Williams, George J.; Gilland, James; Hofer, Richard; Mikellides, Ioannis

2016-01-01

NASA's Hall Effect Rocket with Magnetic Shielding (HERMeS) 12.5 kW Technology Demonstration Unit-1 (TDU-1) has been the subject of extensive technology maturation in preparation for flight system development. Part of the technology maturation effort included experimental evaluation of the TDU-1 thruster with conducting and dielectric front pole cover materials in two different electrical configurations. A graphite front magnetic pole cover thruster configuration with the thruster body electrically tied to cathode, and an alumina front pole cover thruster configuration with the thruster body floating were evaluated. Both configurations were also evaluated at different facility background pressure conditions to evaluate background pressure effects on thruster operation. Performance characterization tests found that higher thruster performance was attained with the graphite front pole cover configuration with the thruster electrically tied to cathode. A total thrust efficiency of 68% and a total specific impulse of 2,820 s was demonstrated at a discharge voltage of 600 V and a discharge power of 12.5 kW. Thruster stability regimes were characterized with respect to the thruster discharge current oscillations and with maps of the discharge current-voltage-magnetic field (IVB). Analysis of TDU-1 discharge current waveforms found that lower normalized discharge current peak-to-peak and root mean square magnitudes were attained when the thruster was electrically floated with alumina front pole covers. Background pressure effects characterization tests indicated that the thruster performance and stability were mostly invariant to changes in the facility background pressure for vacuum chamber pressure below 1×10-5 Torr-Xe (for thruster flow rates of 20.5 mg/s). Power spectral density analysis of the discharge current waveforms showed that increasing the vacuum chamber background pressure resulted in a higher discharge current dominant breathing mode frequency. Finally, IVB maps of the TDU-1 thruster indicated that the discharge current became more oscillatory with higher discharge current peak-to-peak and RMS values with increased facility background pressure at lower thruster mass flow rates; thruster operation at higher flow rates resulted in less change to the thruster's IVB characteristics with elevated background pressure.

Corona discharges from a windmill and its lightning protection tower in winter thunderstorms

NASA Astrophysics Data System (ADS)

Wu, Ting; Wang, Daohong; Rison, William; Thomas, Ronald J.; Edens, Harald E.; Takagi, Nobuyuki; Krehbiel, Paul R.

2017-05-01

This paper presents lightning mapping array (LMA) observations of corona discharges from a windmill and its lightning protection tower in winter thunderstorms in Japan. Corona discharges from the windmill, called windmill coronas, and those from the tower, called tower coronas, are distinctly different. Windmill coronas occur with periodic bursts, generally radiate larger power, and possibly develop to higher altitudes than tower coronas do. A strong negative electric field is necessary for the frequent production of tower coronas but is not apparently related with windmill coronas. These differences are due to the periodic rotation of the windmill and the moving blades which can escape space charges produced by corona discharges and sustain a large local electric field. The production period of windmill coronas is related with the rotation period of the windmill. Surprisingly, for one rotation of the windmill, only two out of the three blades produce detectable discharges and source powers of discharges from these two blades are different. The reason for this phenomenon is still unclear. For tower coronas, the source rate can get very high only when there is a strong negative electric field, and the source power can get very high only when the source rate is very low. The relationship between corona discharges and lightning flashes is investigated. There is no direct evidence that corona discharges can increase the chance of upward leader initiation, but nearby lightning flashes can increase the source rate of corona discharges right after the flashes. The peak of the source height distribution of corona discharges is about 100 m higher than the top of the windmill and the top of the tower. Possible reasons for this result are discussed.

Electron heating and the Electrical Asymmetry Effect in capacitively coupled RF discharges

NASA Astrophysics Data System (ADS)

Schulze, Julian

2011-10-01

For applications of capacitive radio frequency discharges, the control of particle distribution functions at the substrate surface is essential. Their spatio-temporal shape is the result of complex heating mechanisms of the respective species. Enhanced process control, therefore, requires a detailed understanding of the heating dynamics. There are two known modes of discharge operation: α- and γ-mode. In α-mode, most ionization is caused by electron beams generated by the expanding sheaths and field reversals during sheath collapse, while in γ-mode secondary electrons dominate the ionisation. In strongly electronegative discharges, a third heating mode is observed. Due to the low electron density in the discharge center the bulk conductivity is reduced and a high electric field is generated to drive the RF current through the discharge center. In this field, electrons are accelerated and cause significant ionisation in the bulk. This bulk heating mode is observed experimentally and by PIC simulations in CF4 discharges. The electron dynamics and mode transitions as a function of driving voltage and pressure are discussed. Based on a detailed understanding of the heating dynamics, the concept of separate control of the ion mean energy and flux in classical dual-frequency discharges is demonstrated to fail under process relevant conditions. To overcome these limitations of process control, the Electrical Asymmetry Effect (EAE) is proposed in discharges driven at multiple consecutive harmonics with adjustable phase shifts between the driving frequencies. Its concept and a recipe to optimize the driving voltage waveform are introduced. The functionality of the EAE in different gases and first applications to large area solar cell manufacturing are discussed. Finally, limitations caused by the bulk heating in strongly electronegative discharges are outlined.

Taiwan's underwater cultural heritage documentation management

NASA Astrophysics Data System (ADS)

Tung, Y.-Y.

2015-09-01

Taiwan is an important trading and maritime channels for many countries since ancient time. Numerous relics lie underwater due to weather, wars, and other factors. In the year of 2006, Bureau of Cultural Heritage (BOCH) entrusted the Underwater Archaeological Team of Academia Sinica to execute the underwater archaeological investigation projects. Currently, we verified 78 underwater targets, with 78 site of those had been recognized as shipwrecks sites. Up to date, there is a collection of 638 underwater objects from different underwater archaeological sites. Those artefacts are distributed to different institutions and museums. As very diverse management methods/systems are applied for every individual institution, underwater cultural heritage data such as survey, excavation report, research, etc. are poorly organized and disseminated for use. For better communication regarding to Taiwan's underwater cultural heritage in every level, a universal format of documentation should be established. By comparing the existing checklist used in Taiwan with guidelines that are followed in other countries, a more intact and appropriate underwater cultural heritage condition documentation system can be established and adapted in Taiwan.

Machining of AISI D2 Tool Steel with Multiple Hole Electrodes by EDM Process

NASA Astrophysics Data System (ADS)

Prasad Prathipati, R.; Devuri, Venkateswarlu; Cheepu, Muralimohan; Gudimetla, Kondaiah; Uzwal Kiran, R.

2018-03-01

In recent years, with the increasing of technology the demand for machining processes is increasing for the newly developed materials. The conventional machining processes are not adequate to meet the accuracy of the machining of these materials. The non-conventional machining processes of electrical discharge machining is one of the most efficient machining processes is being widely used to machining of high accuracy products of various industries. The optimum selection of process parameters is very important in machining processes as that of an electrical discharge machining as they determine surface quality and dimensional precision of the obtained parts, even though time consumption rate is higher for machining of large dimension features. In this work, D2 high carbon and chromium tool steel has been machined using electrical discharge machining with the multiple hole electrode technique. The D2 steel has several applications such as forming dies, extrusion dies and thread rolling. But the machining of this tool steel is very hard because of it shard alloyed elements of V, Cr and Mo which enhance its strength and wear properties. However, the machining is possible by using electrical discharge machining process and the present study implemented a new technique to reduce the machining time using a multiple hole copper electrode. In this technique, while machining with multiple holes electrode, fin like projections are obtained, which can be removed easily by chipping. Then the finishing is done by using solid electrode. The machining time is reduced to around 50% while using multiple hole electrode technique for electrical discharge machining.

Investigations of Effect of Rotary EDM Electrode on Machining Performance of Al6061 Alloy

NASA Astrophysics Data System (ADS)

Robinson Smart, D. S.; Jenish Smart, Joses; Periasamy, C.; Ratna Kumar, P. S. Samuel

2018-04-01

Electric Discharge Machining is an essential process which is being used for machining desired shape using electrical discharges which creates sparks. There will be electrodes subjected to electric voltage and which are separated by a dielectric liquid. Removing of material will be due to the continuous and rapid current discharges between two electrodes.. The spark is very carefully controlled and localized so that it only affects the surface of the material. Usually in order to prevent the defects which are arising due to the conventional machining, the Electric Discharge Machining (EDM) machining is preferred. Also intricate and complicated shapes can be machined effectively by use of Electric Discharge Machining (EDM). The EDM process usually does not affect the heat treat below the surface. This research work focus on the design and fabrication of rotary EDM tool for machining Al6061alloy and investigation of effect of rotary tool on surface finish, material removal rate and tool wear rate. Also the effect of machining parameters of EDM such as pulse on & off time, current on material Removal Rate (MRR), Surface Roughness (SR) and Electrode wear rate (EWR) have studied. Al6061 alloy can be used for marine and offshore applications by reinforcing some other elements. The investigations have revealed that MRR (material removal rate), surface roughness (Ra) have been improved with the reduction in the tool wear rate (TWR) when the tool is rotating instead of stationary. It was clear that as rotary speed of the tool is increasing the material removal rate is increasing with the reduction of surface finish and tool wear rate.

Consolidation of materials by pulse-discharge processes

NASA Astrophysics Data System (ADS)

Strizhakov, E. L.; Nescoromniy, S. V.

2017-07-01

The article presents the research and the analysis of the pulse-discharge processes of capacitor discharge sintering: CD Stud Welding, capacitor discharge percussion welding (CDPW), high-voltage capacitor welding with an inductive-dynamic drive (HVCW with IDD), pulse electric current sintering (PECS) of powders. The comparative analysis of the impact parameter is presented.

A Better Criterion for the Discharging Time in an RC Circuit

ERIC Educational Resources Information Center

Lima, Fabio M. S.

2015-01-01

When all parts of an electric circuit are at the same potential, no electric current flows and it is said to be in "equilibrium." Otherwise, a current will flow from the higher potential parts to the lower ones, as when we make contact between the plates of a charged capacitor. The resulting discharging process towards equilibrium is a…

Discharging Static Electricity From Inside A Glass Tube

NASA Technical Reports Server (NTRS)

Ellsbury, Walter L.

1994-01-01

Device that contains emitter of alpha particles discharges static electricity from inside wall of glass tube of volumetric-flow calibrator. Includes cylinder that has wall thickness of 1/16 in., diameter about 1/2 in. smaller than inside diameter of tube, and height that extends about 1/2 in. above piston that moves along tube and is part of calibrator.

High energy XeBr electric discharge laser

DOEpatents

Sze, Robert C.; Scott, Peter B.

1981-01-01

A high energy XeBr laser for producing coherent radiation at 282 nm. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr is used as the halogen donor which undergoes harpooning reactions with Xe.sub.M * to form XeBr*.

High energy XeBr electric discharge laser

DOEpatents

Sze, R.C.; Scott, P.B.

A high energy XeBr laser for producing coherent radiation at 282 nm is disclosed. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr, is used as the halogen donor which undergoes harpooning reactions with Xe/sub M/ to form XeBr.

Geometry and surface damage in micro electrical discharge machining of micro-holes

NASA Astrophysics Data System (ADS)

Ekmekci, Bülent; Sayar, Atakan; Tecelli Öpöz, Tahsin; Erden, Abdulkadir

2009-10-01

Geometry and subsurface damage of blind micro-holes produced by micro electrical discharge machining (micro-EDM) is investigated experimentally to explore the relational dependence with respect to pulse energy. For this purpose, micro-holes are machined with various pulse energies on plastic mold steel samples using a tungsten carbide tool electrode and a hydrocarbon-based dielectric liquid. Variations in the micro-hole geometry, micro-hole depth and over-cut in micro-hole diameter are measured. Then, unconventional etching agents are applied on the cross sections to examine micro structural alterations within the substrate. It is observed that the heat-damaged segment is composed of three distinctive layers, which have relatively high thicknesses and vary noticeably with respect to the drilling depth. Crack formation is identified on some sections of the micro-holes even by utilizing low pulse energies during machining. It is concluded that the cracking mechanism is different from cracks encountered on the surfaces when machining is performed by using the conventional EDM process. Moreover, an electrically conductive bridge between work material and debris particles is possible at the end tip during machining which leads to electric discharges between the piled segments of debris particles and the tool electrode during discharging.

A tail of two voltages: Proteomic comparison of the three electric organs of the electric eel

PubMed Central

Traeger, Lindsay L.; Sabat, Grzegorz; Barrett-Wilt, Gregory A.; Wells, Gregg B.; Sussman, Michael R.

2017-01-01

The electric eel (Electrophorus electricus) is unusual among electric fishes because it has three pairs of electric organs that serve multiple biological functions: For navigation and communication, it emits continuous pulses of weak electric discharge (<1 V), but for predation and defense, it intermittently emits lethal strong electric discharges (10 to 600 V). We hypothesized that these two electrogenic outputs have different energetic demands reflected by differences in their proteome and phosphoproteome. We report the use of isotope-assisted quantitative mass spectrometry to test this hypothesis. We observed novel phosphorylation sites in sodium transporters and identified a potassium channel with unique differences in protein concentration among the electric organs. In addition, we found transcription factors and protein kinases that show differential abundance in the strong versus weak electric organs. Our findings support the hypothesis that proteomic differences among electric organs underlie differences in energetic needs, reflecting a trade-off between generating weak voltages continuously and strong voltages intermittently. PMID:28695212

PLASMA DEVICE

DOEpatents

Baker, W.R.

1961-08-22

A device is described for establishing and maintaining a high-energy, rotational plasma for use as a fast discharge capacitor. A disc-shaped, current- conducting plasma is formed in an axinl magnetic field and a crossed electric field, thereby creating rotational kinetic enengy in the plasma. Such energy stored in the rotation of the plasma disc is substantial and is convertible tc electrical energy by generator action in an output line electrically coupled to the plasma volume. Means are then provided for discharging the electrical energy into an external circuit coupled to the output line to produce a very large pulse having an extremely rapid rise time in the waveform thereof. (AE C)

[Survival elongation of Pseudomonas aeruginosa improves power output of microbial fuel cells].

PubMed

You, Ting; Liu, Jihua; Liang, Rubing; Liu, Jianhua

2017-04-25

The secondary metabolites, phenazine products, produced by Pseudomonas aeruginosa can mediate the electrons transfer in microbial fuel cells (MFCs). How increase the total electricity production in MFCs by improving the characteristics of Pseudomonas aeruginosa is one of research hot spots and problems. In this study, P. aeruginosa strain SJTD-1 and its knockout mutant strain SJTD-1 (ΔmvaT) were used to construct MFCs, and the discharge processes of the two MFCs were analyzed to determine the key factors to electricity yields. Results indicated that not only phenazine but also the viable cells in the fermentation broth were essential for the discharge of MFCs. The mutant strain SJTD-1 (ΔmvaT) could produce more phenazine products and continue discharging over 160 hours in MFCs, more than that of the wild-type SJTD-1 strain (90 hours discharging time). The total electricity generated by SJTD-1 (ΔmvaT) strain could achieve 2.32 J in the fermentation process, much higher than the total 1.30 J electricity of the wild-type SJTD-1 strain. Further cell growth analysis showed that the mutant strain SJTD-1 (ΔmvaT) could keep a longer stationary period, survive much longer in MFCs and therefore, discharge more electron than those of the wild-type SJTD-1 strain. Therefore, the cell survival elongation of P. aeruginosa in MFCs could enhance its discharging time and improve the overall energy yield. This work could give a clue to improve the characteristics of MFCs using genetic engineering strain, and could promote related application studies on MFCs.

Determining insulation condition of 110kV instrument transformers. Linking PD measurement results from both gas chromatography and electrical method

NASA Astrophysics Data System (ADS)

Dan, C.; Morar, R.

2017-05-01

Working methods for on site testing of insulations: Gas chromatography (using the TFGA-P200 chromatographer); Electrical measurements of partial discharge levels using the digital detection, recording, analysis and partial discharge acquisition system, MPD600. First performed, between 2000-2015, were the chromatographic analyses concerning electrical insulating environments of: 102 current transformers, 110kV. Items in operation, functioning in 110/20kV substations. 38 voltage transformers, 110kV also in operation, functioning in 110/20kV substations. Then, electrical measurements of partial discharge inside instrument transformers, on site (power substations) were made (starting in the year 2009, over a 7-year period, collecting data until the year 2015) according to the provisions of standard EN 61869-1:2007 „Instrument transformers. General requirements”, applying, assimilated to it, type A partial discharge test procedure, using as test voltage the very rated 110kV distribution grid voltage. Given the results of two parallel measurements, containing: to this type of failure specific gas amount (H 2) and the quantitative partial discharge’ level, establishing a clear dependence between the quantity of partial discharges and the type and amount of in oil dissolved gases inside equipments affected by this type of defect: partial discharges, was expected. Of the „population” of instrument transformers subject of the two parallel measurements, the dependency between Q IEC (apparent charge) and (H 2) (hydrogen, gas amount dissolved within their insulating environment) represents a finite assemblage situated between the two limits developed on an empirical basis.

Approximations useful for the prediction of electrostatic discharges for simple electrode geometries

NASA Technical Reports Server (NTRS)

Edmonds, L.

1986-01-01

The report provides approximations for estimating the capacitance and the ratio of electric field strength to potential for a certain class of electrode geometries. The geometry consists of an electrode near a grounded plane, with the electrode being a surface of revolution about the perpendicular to the plane. Some examples which show the accuracy of the capacitance estimate and the accuracy of the estimate of electric field over potential can be found in the appendix. When it is possible to estimate the potential of the electrode, knowing the ratio of electric field to potential will help to determine if an electrostatic discharge is likely to occur. Knowing the capacitance will help to determine the strength of the discharge (the energy released by it) if it does occur. A brief discussion of discharge mechanisms is given. The medium between the electrode and the grounded plane may be a neutral gas, a vacuum, or an unchanged homogeneous isotropic dielectric.

Positive column of a glow discharge in neon with charged dust grains (a review)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polyakov, D. N., E-mail: cryolab@ihed.ras.ru; Shumova, V. V.; Vasilyak, L. M.

The effect of charged micron-size dust grains (microparticles) on the electric parameters of the positive column of a low-pressure dc glow discharge in neon has been studied experimentally and numerically. Numerical analysis is carried out in the diffusion-drift approximation with allowance for the interaction of dust grains with metastable neon atoms. In a discharge with a dust grain cloud, the longitudinal electric field increases. As the number density of dust grains in an axisymmetric cylindrical dust cloud rises, the growth of the electric field saturates. It is shown that the contribution of metastable atoms to ionization is higher in amore » discharge with dust grains, in spite of the quenching of metastable atoms on dust grains. The processes of charging of dust grains and the dust cloud are considered. As the number density of dust grains rises, their charge decreases, while the space charge of the dust cloud increases. The results obtained can be used in plasma technologies involving microparticles.« less

Report on the survey for electrostatic discharges on Mars using NASA's Deep Space Network (DSN)

NASA Astrophysics Data System (ADS)

Arabshahi, S.; Majid, W.; Geldzahler, B.; Kocz, J.; Schulter, T.; White, L.

2017-12-01

Mars atmosphere has strong dust activity. It is suggested that the larger regional storms are capable of producing electric fields large enough to initiate electrostatic discharges. The storms have charging process similar to terrestrial dust devils and have hot cores and complicated vortex winds similar to terrestrial thunderstorms. However, due to uncertainties in our understanding of the electrical environment of the storms and absence of related in-situ measurements, the existence (or non-existence) of such electrostatic discharges on the planet is yet to be confirmed. Knowing about the electrical activity on Mars is essential for future human explorations of the planet. We have recently launched a long-term monitoring campaign at NASA's Madrid Deep Space Communication Complex (MDSCC) to search for powerful discharges on Mars. The search occurs during routine tracking of Mars orbiting spacecraft by Deep Space Network (DSN) radio telescope. In this presentation, we will report on the result of processing and analysis of the data from the first six months of our campaign.

Analysis on the correlation between temperature and discharge characteristic of cloud-to-ground lightning discharge plasma with multiple return strokes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qu Haiyan; Chang Zhengshi; Yuan Ping

2011-01-15

The spectra of cloud-to-ground lightning with multiple return strokes have been obtained by using a slitless spectrograph on the Chinese Tibet plateau. Combining the spectra with synchronous electrical information, the correlation among spectral properties, channel temperatures and discharge characteristics, and thermal effects of current is discussed for the first time. The results show that the channel plasma temperature varies significantly from stroke to stroke within a given flash, and the total intensity of spectra is directly proportional to the amplitude of electric field change. Moreover, the positive correlation has been confirmed between the channel plasma temperature and the thermal effectmore » which shows the effect of the electric current accumulation. It is inferred that the total intensity of the spectra should be directly proportional to the intensity of discharge current, and channel temperature is correlated positively with the energy transmission in one return stroke.« less

46 CFR 167.05-40 - Underwater survey.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Underwater survey. 167.05-40 Section 167.05-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Definitions § 167.05-40 Underwater survey. Underwater survey means the examination of the vessel's underwater...

46 CFR 167.05-40 - Underwater survey.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Underwater survey. 167.05-40 Section 167.05-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Definitions § 167.05-40 Underwater survey. Underwater survey means the examination of the vessel's underwater...

46 CFR 167.05-40 - Underwater survey.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Underwater survey. 167.05-40 Section 167.05-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Definitions § 167.05-40 Underwater survey. Underwater survey means the examination of the vessel's underwater...

46 CFR 167.05-40 - Underwater survey.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Underwater survey. 167.05-40 Section 167.05-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Definitions § 167.05-40 Underwater survey. Underwater survey means the examination of the vessel's underwater...

46 CFR 167.05-40 - Underwater survey.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Underwater survey. 167.05-40 Section 167.05-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Definitions § 167.05-40 Underwater survey. Underwater survey means the examination of the vessel's underwater...

Network Computing for Distributed Underwater Acoustic Sensors

DTIC Science & Technology

2014-03-31

underwater sensor network with mobility. In preparation. [3] EvoLogics (2013), Underwater Acoustic Modems, (Product Information Guide... Wireless Communications, 9(9), 2934–2944. [21] Pompili, D. and Akyildiz, I. (2010), A multimedia cross-layer protocol for underwater acoustic sensor networks ... Network Computing for Distributed Underwater Acoustic Sensors M. Barbeau E. Kranakis

Wavelet-based information filtering for fault diagnosis of electric drive systems in electric ships.

PubMed

Silva, Andre A; Gupta, Shalabh; Bazzi, Ali M; Ulatowski, Arthur

2017-09-22

Electric machines and drives have enjoyed extensive applications in the field of electric vehicles (e.g., electric ships, boats, cars, and underwater vessels) due to their ease of scalability and wide range of operating conditions. This stems from their ability to generate the desired torque and power levels for propulsion under various external load conditions. However, as with the most electrical systems, the electric drives are prone to component failures that can degrade their performance, reduce the efficiency, and require expensive maintenance. Therefore, for safe and reliable operation of electric vehicles, there is a need for automated early diagnostics of critical failures such as broken rotor bars and electrical phase failures. In this regard, this paper presents a fault diagnosis methodology for electric drives in electric ships. This methodology utilizes the two-dimensional, i.e. scale-shift, wavelet transform of the sensor data to filter optimal information-rich regions which can enhance the diagnosis accuracy as well as reduce the computational complexity of the classifier. The methodology was tested on sensor data generated from an experimentally validated simulation model of electric drives under various cruising speed conditions. The results in comparison with other existing techniques show a high correct classification rate with low false alarm and miss detection rates. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

The Effect of a Corona Discharge on a Lightning Attachment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aleksandrov, N.L.; Bazelyan, E.M.; Raizer, Yu.P.

2005-01-15

The interaction between the lightning leader and the space charge accumulated near the top of a ground object in the atmospheric electric field is considered using analytical and numerical models developed earlier to describe spark discharges in long laboratory gaps. The specific features of a nonstationary corona discharge that develops in the electric field of a thundercloud and a downward lightning leader are analyzed. Conditions for the development of an upward lightning discharge from a ground object and for the propagation of an upward-connecting leader from the object toward a downward lightning leader (the process determining the point of strikemore » to the ground) are investigated. Possible mechanisms for the interaction of the corona space charge with an upward leader and prospects of using it to control downward lightning discharges are analyzed.« less

Plasma sterilization of polyethylene terephthalate bottles by pulsed corona discharge at atmospheric pressure.

PubMed

Masaoka, Satoshi

2007-06-01

A pulsed power supply was used to generate a corona discharge on a polyethylene terephthalate bottle, to conduct plasma sterilization at atmospheric pressure. Before generating such a discharge, minute quantities of water were attached to the inner surface of the bottle and to the surface of a high voltage (HV) electrode inserted into the bottle. Next, high-voltage pulses of electricity were discharged between electrodes for 6.0s, while rotating the bottle. The resulting spore log reduction values of Bacillus subtilis and Aspergillus niger on the inner surface of the bottle were 5.5 and 6 or higher, respectively, and those on the HV electrode surface were each 6 or higher for both strains. The presence of the by-products gaseous ozone, hydrogen peroxide, and nitric ions resulting from the electrical discharge was confirmed.

Origin of life: hypothesized roles of high-energy electrical discharges, infrared radiation, thermosynthesis and pre-photosynthesis.

PubMed

Trevors, J T

2012-12-01

The hypothesis is proposed that during the organization of pre-biotic bacterial cell(s), high-energy electrical discharges, infrared radiation (IR), thermosynthesis and possibly pre-photosynthesis were central to the origin of life. High-energy electrical discharges generated some simple organic molecules available for the origin of life. Infrared radiation, both incoming to the Earth and generated on the cooling Earth with day/night and warming/cooling cycles, was a component of heat engine thermosynthesis before enzymes and the genetic code were present. Eventually, a primitive forerunner of photosynthesis and the capability to capture visible light emerged. In addition, the dual particle-wave nature of light is discussed from the perspective that life requires light acting both as a wave and particle.

GAS DISCHARGE DEVICES

DOEpatents

Arrol, W.J.; Jefferson, S.

1957-08-27

The construction of gas discharge devices where the object is to provide a gas discharge device having a high dark current and stabilized striking voltage is described. The inventors have discovered that the introduction of tritium gas into a discharge device with a subsequent electrical discharge in the device will deposit tritium on the inside of the chamber. The tritium acts to emit beta rays amd is an effective and non-hazardous way of improving the abovementioned discharge tube characteristics

Nontraditional, Safe, High Voltage Rechargeable Cells of Long Cycle Life.

PubMed

Braga, Maria Helena; M Subramaniyam, Chandrasekar; Murchison, Andrew J; Goodenough, John B

2018-05-23

A room-temperature all-solid-state rechargeable battery cell containing a tandem electrolyte consisting of a Li + -glass electrolyte in contact with a lithium anode and a plasticizer in contact with a conventional, low cost oxide host cathode was charged to 5 V versus lithium with a charge/discharge cycle life of over 23,000 cycles at a rate of 153 mA·g -1 of active material. A larger positive electrode cell with 329 cycles had a capacity of 585 mAh·g -1 at a cutoff of 2.5 V and a current of 23 mA·g -1 of the active material; the capacity rose with cycle number over the 329 cycles tested during 13 consecutive months. Another cell had a discharge voltage from 4.5 to 3.7 V over 316 cycles at a rate of 46 mA·g -1 of active material. Both the Li + -glass electrolyte and the plasticizer contain electric dipoles that respond to the internal electric fields generated during charge by a redistribution of mobile cations in the glass and by extraction of Li + from the active cathode host particles. The electric dipoles remain oriented during discharge to retain an internal electric field after a discharge. The plasticizer accommodates to the volume changes in the active cathode particles during charge/discharge cycling and retains during charge the Li + extracted from the cathode particles at the plasticizer/cathode-particle interface; return of these Li + to the active cathode particles during discharge only involves a displacement back across the plasticizer/cathode interface and transport within the cathode particle. A slow motion at room temperature of the electric dipoles in the Li + -glass electrolyte increases with time the electric field across the EDLC of the anode/Li + -glass interface to where Li + from the glass electrolyte is plated on the anode without being replenished from the cathode, which charges the Li + -glass electrolyte negative and consequently the glass side of the Li + -glass/plasticizer EDLC. Stripping back the Li + to the Li + -glass during discharge is enhanced by the negative charge in the Li + -glass. Since the Li + -glass is not reduced on contact with metallic lithium, no passivating interface layer contributes to a capacity fade; instead, the discharge capacity increases with cycle number as a result of dipole polarization in the Li + -glass electrolyte leading to a capacity increase of the Li + -glass/plasticizer EDLC. The storage of electric power by both faradaic electrochemical extraction/insertion of Li + in the cathode and electrostatic stored energy in the EDLCs provides a safe and fast charge and discharge with a long cycle life and a greater capacity than can be provided by the cathode host extraction/insertion reaction. The cell can be charged to a high voltage versus a lithium anode because of the added charge of the EDLCs.

Stability analysis of hybrid-driven underwater glider

NASA Astrophysics Data System (ADS)

Niu, Wen-dong; Wang, Shu-xin; Wang, Yan-hui; Song, Yang; Zhu, Ya-qiang

2017-10-01

Hybrid-driven underwater glider is a new type of unmanned underwater vehicle, which combines the advantages of autonomous underwater vehicles and traditional underwater gliders. The autonomous underwater vehicles have good maneuverability and can travel with a high speed, while the traditional underwater gliders are highlighted by low power consumption, long voyage, long endurance and good stealth characteristics. The hybrid-driven underwater gliders can realize variable motion profiles by their own buoyancy-driven and propeller propulsion systems. Stability of the mechanical system determines the performance of the system. In this paper, the Petrel-II hybrid-driven underwater glider developed by Tianjin University is selected as the research object and the stability of hybrid-driven underwater glider unitedly controlled by buoyancy and propeller has been targeted and evidenced. The dimensionless equations of the hybrid-driven underwater glider are obtained when the propeller is working. Then, the steady speed and steady glide path angle under steady-state motion have also been achieved. The steady-state operating conditions can be calculated when the hybrid-driven underwater glider reaches the desired steady-state motion. And the steadystate operating conditions are relatively conservative at the lower bound of the velocity range compared with the range of the velocity derived from the method of the composite Lyapunov function. By calculating the hydrodynamic coefficients of the Petrel-II hybrid-driven underwater glider, the simulation analysis has been conducted. In addition, the results of the field trials conducted in the South China Sea and the Danjiangkou Reservoir of China have been presented to illustrate the validity of the analysis and simulation, and to show the feasibility of the method of the composite Lyapunov function which verifies the stability of the Petrel-II hybrid-driven underwater glider.

Comparison of advanced rechargeable batteries for autonomous underwater vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Descroix, J.P.; Chagnon, G.

1994-12-31

For AUV to be promising in the field of military oceanic and scientific missions, it is of great importance that power sources must meet the system needs. In view of this, this article will address the present and near term options for electric power sources. Evaluation is based on a hypothetical AUV. It is expected that considerable results will be achieved with respect to the possible options and cost needed in the manufacture of such power sources. 5 refs.

On the Mutual Information of Multi-hop Acoustic Sensors Network in Underwater Wireless Communication

DTIC Science & Technology

2014-05-01

DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. The University of the District of Columbia Computer Science and Informati Briana Lowe Wellman Washington...financial support throughout my Master’s study and research. Also, I would like to acknowledge the Faculty of the Electrical and Computer Engineering...received bits are in error, and then compute the bit-error-rate as the number of bit errors divided by the total number of bits in the transmitted signal

The OTEC connection - Power from the sea

NASA Astrophysics Data System (ADS)

Petty, D.

1980-02-01

OTEC is discussed as a means of contributing to United States energy self-sufficiency. The technology involved in the conversion of ocean thermal gradients found in tropical regions to electricity transmittable by submarine cable is examined, with attention given to the operating principles of open- and closed-cycle Rankine engines and design considerations for the evaporators, condensers and heat exchangers. The environmental impact and economics of OTEC are considered, and Department of Energy research projects in areas of OTEC technology including heat transfer, biofouling, environmental assessment, underwater electrical transmission and mooring and test plants are indicated. It is pointed out that US islands presently offer excellent markets for early commercial OTEC plants, with Gulf Coast markets requiring further technology developments to be economically attractive.

Depolarization current relaxation process of insulating dielectrics after corona poling under different charging conditions

NASA Astrophysics Data System (ADS)

Zhang, J. W.; Zhou, T. C.; Wang, J. X.; Yang, X. F.; Zhu, F.; Tian, L. M.; Liu, R. T.

2017-10-01

As an insulating dielectric, polyimide is favorable for the application of optoelectronics, electrical insulation system in electric power industry, insulating, and packaging materials in space aircraft, due to its excellent thermal, mechanical and electrical insulating stability. The charge storage profile of such insulating dielectric is utmost important to its application, when it is exposed to electron irradiation, high voltage corona discharge or other treatments. These treatments could induce changes in physical and chemical properties of treated samples. To investigate the charge storage mechanism of the insulating dielectrics after high-voltage corona discharge, the relaxation processes responsible for corona charged polyimide films under different poling conditions were analyzed by the Thermally Stimulated Discharge Currents method (TSDC). In the results of thermal relaxation process, the appearance of various peaks in TSDC spectra provided a deep insight into the molecular status in the dielectric material and reflected stored space charge relaxation process in the insulating polymers after corona discharge treatments. Furthermore, the different space charge distribution status under various poling temperature and different discharge voltage level were also investigated, which could partly reflect the influence of the ambiance condition on the functional dielectrics after corona poling.

The Impact of Harness Impedance on Hall Thruster Discharge Oscillations

NASA Technical Reports Server (NTRS)

Pinero, Luis R.

2017-01-01

Hall thrusters exhibit characteristic discharge voltage and current oscillations during steady-state operation. The lower frequency breathing-mode current oscillations are inherent to each thruster and could impact thruster operation and power processing unit (PPU) design. The design of the discharge output filter, in particular, the output capacitor is important because it supplies the high peak current oscillations that the thruster demands. However, space-rated, high-voltage capacitors are not readily available and can have significant mass and volume. So, it is important for a PPU designer to know what is the minimum amount of capacitance required to operate a thruster. Through Simulation Program with Integrated Circuit Emphasis modeling and electrical measurements on the Hall Effect Rocket with Magnetic Shielding thruster, it was shown that the harness impedance between the power supply and the thruster is the main contributor towards generating voltage ripple at the thruster. Also, increasing the size of the discharge filter capacitor, as previously implemented during thruster tests, does not reduce the voltage oscillations. The electrical characteristics of the electrical harness between the discharge supply and the thruster is crucial to system performance and could have a negative impact on performance, life and operation.

The Impact of Harness Impedance on Hall Thruster Discharge Oscillations

NASA Technical Reports Server (NTRS)

Pinero, Luis R.

2017-01-01

Hall thrusters exhibit characteristic discharge voltage and current oscillations during steady-state operation. The lower frequency breathing-mode current oscillations are inherent to each thruster and could impact thruster operation and PPU design. The design of the discharge output filter, in particular, the output capacitor is important because it supplies the high peak current oscillations that the thruster demands. However, space-rated, high-voltage capacitors are not readily available and can have significant mass and volume. So, it is important for a PPU designer to know what is the minimum amount of capacitance required to operate a thruster. Through SPICE modeling and electrical measurements on the Hall Effect Rocket with Magnetic Shielding (HERMeS) thruster, it was shown that the harness impedance between the power supply and the thruster is the main contributor towards generating voltage ripple at the thruster. Also, increasing the size of the discharge filter capacitor, as previously implemented during thruster tests, does not reduce the voltage oscillations. The electrical characteristics of the electrical harness between the discharge supply and the thruster is crucial to system performance and could have a negative impact on performance, life and operation.

Modeling of a Ne/Xe dielectric barrier discharge excilamp for improvement of VUV radiation production

NASA Astrophysics Data System (ADS)

Khodja, K.; Belasri, A.; Loukil, H.

2017-08-01

This work is devoted to excimer lamp efficiency optimization by using a homogenous discharge model of a dielectric barrier discharge in a Ne-Xe mixture. The model includes the plasma chemistry, electrical circuit, and Boltzmann equation. In this paper, we are particularly interested in the electrical and kinetic properties and light output generated by the DBD. Xenon is chosen for its high luminescence in the range of vacuum UV radiation around 173 nm. Our study is motivated by interest in this type of discharge in many industrial applications, including the achievement of high light output lamps. In this work, we used an applied sinusoidal voltage, frequency, gas pressure, and concentration in the ranges of 2-8 kV, 10-200 kHz, 100-800 Torr, and 10-50%, respectively. The analyzed results concern the voltage V p across the gap, the dielectric voltage V d, the discharge current I, and the particles densities. We also investigated the effect of the electric parameters and xenon concentration on the lamp efficiency. This investigation will allow one to find out the appropriate parameters for Ne/Xe DBD excilamps to improve their efficiency.

D region disturbances caused by electromagnetic pulses from lightning

NASA Technical Reports Server (NTRS)

Rodriguez, Juan V.; Inan, Umran S.; Bell, Timothy F.

1992-01-01

Attention is given to a simple formulation of the propagation and absorption in a magnetized collisional plasma of EM pulses from lightning which describes the effect of discharge orientation and radiated electric field on the structure and magnitude of heating and secondary ionization in the D region. Radiation from most lightning discharges can heat substantially, but only the most intense (not less than 20 V/m) are likely to cause ionization enhancements not less than 10 percent of the ambient in a single ionization cycle. This dependence on the radiated electric field is modified by the discharge radiation pattern: a horizontal cloud discharge tends to cause larger heating and ionizaton maxima while a vertical return stroke causes disturbances of a larger horizontal extent.

Characterization of millimetre magnitude atmospheric pressure streamer discharge in pin-to-plane dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Xu, S. J.; Zhang, Y. H.; Yu, Z.; Yao, J.; Zhang, Z. T.

2013-03-01

The streamer regime of pin-to-plane dielectric barrier discharge in air was studied by means of fast photography, electrical measurement and photoelectricity. The fast photographs of positive streamer were obtained by CCD camera with micro lens. The exposure time is one microseconds. The images illustrate that the streamer is non-axisymmetric because of some random factors, such as surface charge position, space charge distribution, gas liquidity and so on. In fact, the streamer propagates along bend discharge channel. The bending degree increases with the electric field strengthen. By surveying a mass of images, the diameter of streamer, height of surface charge effect and scope of surface charge was estimate used to describe the shape of streamer.

Presenting rhythm in sudden deaths temporally proximate to discharge of TASER conducted electrical weapons.

PubMed

Swerdlow, Charles D; Fishbein, Michael C; Chaman, Linda; Lakkireddy, Dhanunjaya R; Tchou, Patrick

2009-08-01

Sudden deaths proximate to use of conducted electrical weapons (CEWs) have been attributed to cardiac electrical stimulation. The rhythm in death caused by rapid, cardiac electrical stimulation usually is ventricular fibrillation (VF); electrical stimulation has not been reported to cause asystole or pulseless electrical activity (PEA). The authors studied the presenting rhythms in sudden deaths temporally proximate to use of TASER CEWs to estimate the likelihood that these deaths could be caused by cardiac electrical stimulation. This was a retrospective review of CEW-associated, nontraumatic sudden deaths from 2001 to 2008. Emergency medical services (EMS), autopsy, and law enforcement reports were requested and analyzed. Subjects were included if they collapsed within 15 minutes of CEW discharge and the first cardiac arrest rhythm was reported. Records for 200 cases were received. The presenting rhythm was reported for 56 of 118 subjects who collapsed within 15 minutes (47%). The rhythm was VF in four subjects (7%; 95% confidence interval [CI] = 3% to 17%) and bradycardia-asystole or PEA in 52 subjects (93%; 95% CI = 83% to 97%). None of the eight subjects who collapsed during electrocardiogram (ECG) monitoring had VF. Only one subject (2%) collapsed immediately after CEW discharge. This was the only death typical of electrically induced VF (2%, 95% CI = 0% to 9%). An additional 4 subjects (7%) collapsed within 1 minute, and the remaining 51 subjects (91%) collapsed more than 1 minute later. The time from collapse to first recorded rhythm was 3 minutes or less in 35 subjects (62%) and 5 minutes or less in 43 subjects (77%). In sudden deaths proximate to CEW discharge, immediate collapse is unusual, and VF is an uncommon VF presenting rhythm. Within study limitations, including selection bias and the possibility that VF terminated before the presenting rhythm was recorded, these data do not support electrically induced VF as a common mechanism of these sudden deaths.

Spacecraft high-voltage power supply construction

NASA Technical Reports Server (NTRS)

Sutton, J. F.; Stern, J. E.

1975-01-01

The design techniques, circuit components, fabrication techniques, and past experience used in successful high-voltage power supplies for spacecraft flight systems are described. A discussion of the basic physics of electrical discharges in gases is included and a design rationale for the prevention of electrical discharges is provided. Also included are typical examples of proven spacecraft high-voltage power supplies with typical specifications for design, fabrication, and testing.

CALUTRON

DOEpatents

Clark, A.F.

1959-06-16

A means of eliminating oscillating electrons from the arc slit region of calutron ion sources is offered. Free electrons and ions generated by the beam bombarding atoms of ambient atmosphere are discharged by a fin arrangement which sets up an electric field. The discharged ions travel toward a recess in which a fin and blister'' effect limits oscillations to one region from which they are removed by reversed electric fields. (T.R.H.)

Closed Cycle Electric Discharge Laser Design Investigation

DTIC Science & Technology

1978-03-01

Report Number Assigned by Contract Monitor: NASA CR- 135408 Comments on Document: Archive, RRI, DEW Descriptors, Keywords: Closed Cycle Electric...Discharge Laser Design Investigation Carbon Dioxide Monoxide Space Airborne Heat Disposal Point Track Power Solar Generator Radiation Pages: 00100...Cataloged Date: Nov 27,1992 Contract Number: NAS 3-20100 Document Type: HC Number of Copies In Library: 000001 Record ID: 25219 Source of Document: DEW

Effect of turbulent flow on an atmospheric-pressure AC powered gliding arc discharge

NASA Astrophysics Data System (ADS)

Kong, Chengdong; Gao, Jinlong; Zhu, Jiajian; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan

2018-06-01

A high-power gliding arc (GA) discharge was generated in a turbulent air flow driven by a 35 kHz alternating current electric power supply. The effects of the flow rate on the characteristics of the GA discharge were investigated using combined optical and electrical diagnostics. Phenomenologically, the GA discharge exhibits two types of discharge, i.e., glow type and spark type, depending on the flow rates and input powers. The glow-type discharge, which has peak currents of hundreds of milliamperes, is sustained at low flow rates. The spark-type discharge, which is characterized by a sharp current spike of several amperes with duration of less than 1 μs, occurs more frequently as the flow rate increases. Higher input power can suppress spark-type discharges in moderate turbulence, but this effect becomes weak under high turbulent conditions. Physically, the transition between glow- and spark-type is initiated by the short cutting events and the local re-ignition events. Short cutting events occur owing to the twisting, wrinkling, and stretching of the plasma columns that are governed by the relatively large vortexes in the flow. Local re-ignition events, which are defined as re-ignition along plasma columns, are detected in strong turbulence due to increment of the impedance of the plasma column and consequently the internal electric field strength. It is suggested that the vortexes with length scales smaller than the size of the plasma can penetrate into the plasma column and promote mixing with surroundings to accelerate the energy dissipation. Therefore, the turbulent flow influences the GA discharges by ruling the short cutting events with relatively large vortexes and the local re-ignition events with small vortexes.

Methods and Systems for Configuring Sensor Acquisition Based on Pressure Steps

NASA Technical Reports Server (NTRS)

DeDonato, Mathew (Inventor)

2015-01-01

Technologies are provided for underwater measurements. A system includes an underwater vessels including: a plurality of sensors disposed thereon for measuring underwater properties; and a programmable controller configured to selectively activate the plurality of sensors based at least in part on underwater pressure. A user may program at what pressure ranges certain sensors are activated to measure selected properties, and may also program the ascent/descent rate of the underwater vessel, which is correlated with the underwater pressure.

A Comparison of Inductive Sensors in the Characterization of Partial Discharges and Electrical Noise Using the Chromatic Technique

PubMed Central

Ardila-Rey, Jorge Alfredo; Montaña, Johny; Schurch, Roger; Covolan Ulson, José Alfredo; Bani, Nurul Aini

2018-01-01

Partial discharges (PDs) are one of the most important classes of ageing processes that occur within electrical insulation. PD detection is a standardized technique to qualify the state of the insulation in electric assets such as machines and power cables. Generally, the classical phase-resolved partial discharge (PRPD) patterns are used to perform the identification of the type of PD source when they are related to a specific degradation process and when the electrical noise level is low compared to the magnitudes of the PD signals. However, in practical applications such as measurements carried out in the field or in industrial environments, several PD sources and large noise signals are usually present simultaneously. In this study, three different inductive sensors have been used to evaluate and compare their performance in the detection and separation of multiple PD sources by applying the chromatic technique to each of the measured signals. PMID:29596337

Radio Frequencies Emitted by Mobile Granular Materials: A Basis for Remote Sensing of Sand and Dust Activity on Mars and Earth

NASA Technical Reports Server (NTRS)

Marshall, J.; Farrell, W.; Houser, G.; Bratton, C.

1999-01-01

In recent laboratory experiments, measurements were made of microsecond radio-wave (RF) bursts emitted by grains of sand as they energetically circulated in a closed, electrically ungrounded chamber. The bursts appeared to result from nanoscale electrical discharging from grain surfaces. Both the magnitude and wave form of the RF pulses varied with the type of material undergoing motion. The release of RF from electrical discharging is a well-known phenomenon, but it is generally measured on much larger energy scales (e.g., in association with lightning or electrical motors). This phenomenon might be used to detect, on planetary surfaces, the motion and composition of sand moving over dunes, the turbulent motion of fine particles in dust storms, highly-energetic grain and rock collisions in volcanic eruptions, and frictional grinding of granular materials in dry debris flows, landslides, and avalanches. The occurrence of these discharges has been predicted from theoretical considerations Additional information is contained in the original.

Method and apparatus for separating material

DOEpatents

Oder, Robin R.; Jamison, Russell E.

2006-10-24

An apparatus for sorting particles composed of a mixture of particles with differing physical and chemical characteristics. The apparatus includes a comminutor, a mechanism for removing particles from the inside of the comminutor which are intermediate in size between the feed to the comminutor and the product of comminution, a mechanism for either discharging particles taken from the comminutor to a reject stream or providing them to a size classification apparatus such as screening, a mechanism for returning the oversize particles to the comminutor or for discharging them to the reject stream, an electric mechanism for separating particles with an electrical force disposed adjacent to a magnet mechanism, a mechanism for providing the particles to the magnet mechanism and the electric mechanism and for providing triboelectric and capacitive charges to the particles, and a mechanism for returning one of the products of electric and magnetic separation to the comminutor while discharging the other to the reject stream. A method for sorting particles composed of a mixture of particles with differing physical and chemical characteristics.

Electron-Impact-Ionization and Electron-Attachment Cross Sections of Radicals Important in Transient Gaseous Discharges.

DTIC Science & Technology

1988-02-05

for understanding the microscopic processes of electrical discharges and for designing gaseous discharge switches. High power gaseous discharge switches...half-maximum) energy resolution. The electron gun and ion extraction were of the same design of Srivastava at the Jet Propulsion Laboratory. Ions...photons. - The observed current switching can be applied to the design of discharge switches. Elec- tron transport parameters are needed for the

Low-pressure electrical discharge experiment to simulate high-altitude lightning above thunderclouds

NASA Technical Reports Server (NTRS)

Jarzembski, M. A.; Srivastava, V.

1995-01-01

Recently, extremely interesting high-altitude cloud-ionosphere electrical discharges, like lightning above thunderstorms, have been observed from NASA's space shuttle missions and during airborne and ground-based experiments. To understand these discharges, a new experiment was conceived to simulate a thundercloud in a vacuum chamber using a dielectric in particulate form into which electrodes were inserted to create charge centers analogous to those in an electrified cloud. To represent the ionosphere, a conducting medium (metallic plate) was introduced at the top of the chamber. It was found that for different pressures between approximately 1 and 300 mb, corresponding to various upper atmospheric altitudes, different discharges occurred above the simulated thundercloud, and these bore a remarkable similarity to the observed atmospheric phenomena. At pressures greater than 300 mb, these discharges were rare and only discharges within the simulated thundercloud were observed. Use of a particulate dielectric was critical for the successful simulation of the high-altitude lightning.

Sterilization of medical equipment and contaminated articles by making use of a resistive barrier discharge

NASA Astrophysics Data System (ADS)

Uhm, Han S.; Kang, Jung G.; Choi, Eun H.; Cho, Guang S.

2012-08-01

Presented here is an apparatus consisting of an atmospheric resistive-barrier discharge for the sterilization of medical tools wrapped in typical hospital cloths, for the sterilization of manufactured drugs in typical packaging materials, and for the sterilization of biologically-contaminated articles. The sterilization apparatus consists of layers of the resistive-barrier discharge device operating at room temperature, a sterilization chamber, and an ozone destruction device. An electrical discharge in the resistive-barrier discharge system generates an atmospheric plasma in oxygen gas, generating ozone, which in turn efficiently sterilizes medical tools and biologically contaminated articles at room temperature. A sterilization experiment was carried out at an apparatus volume of 100 liters, with a sterilization chamber volume of 60 liters, and a discharge device volume of 40 liters. The sterilization in this experiment required 60 W of power for 5 hours of residence time. For a given sterilization time, the required electrical power was proportional to the apparatus volume. Ozone in the sterilization chamber was destroyed safely after sterilization.

Electrical characteristics and energy budget of dielectric barrier discharges in argon at atmospheric pressure

NASA Astrophysics Data System (ADS)

Becker, Markus M.; Hoder, Tomas; Loffhagen, Detlef

2014-10-01

Recently, an asymmetric dielectric barrier discharge ignited in atmospheric pressure argon in a single filament configuration has been analysed by experiments and modelling [1,2]. A special feature of the discharge under consideration is the occurrence of two different discharge modes at different amplitudes of the sinusoidal voltage supply. At voltages below the critical voltage of 2 kV ordinary filamentary discharges occur, while at higher voltages discharges with striated filaments emerge. In the present contribution the mode transition is investigated with respect to the electrical characteristics as well as the electron energy budget by means of numerical modelling. It is found that the mode transition caused by an increase of the voltage amplitude is accompanied by a non-linear change of the power density and a marked rise of the electron energy gain in chemo-ionization processes. This work was partly supported by the German Research Foundation within the Collaborative Research Centre Transregio 24.

Research on Lessening of Bonding Effects Between the Metallic and Non-Metallic Surfaces Through the Graphite Films Deposited with Pulsed Electrical Discharges Process

NASA Astrophysics Data System (ADS)

Marin, L.; Topala, P.

2017-06-01

The paper presents the results of experimental research on the physics of natural graphite film formation, the establishment of chemical composition and functional properties of the graphite films, formed on metal surfaces, as a result of the action of plasma in the air environment, at a normal pressure, under the electrical discharge in impulse conditions (EDI). The researchings were performed in the frame of doctoral thesis “Research on lessening of the bonding effects between the metallic and nonmetallic surfaces through the graphite films” and aimed to identify the phenomena that occur at the interface metal/ film of graphite, and to identify also the technological applications that it may have the surface treatment for submitting the films of graphite on metallic surfaces achieved through an innovative process of electrical pulsed discharges. After the research works from the PhD theme above mentioned, a number of interesting properties of graphite pellicle have been identified ie reducing of metal surface polarity. This led to drastic decreases for the values of adhesion when bonding of metal surfaces was performed using a structural polyurethane adhesive designed by ICECHIM. Following the thermo-gravimetric analysis, performed of the graphite film obtained by process of electrical pulsed discharges, have been also discovered other interesting properties for this, ie reversible mass additions at specific values of the working temperature Chemical and scanning electron microscopy analysis have revealed that on the metallic surface subjected to electrical pulsed discharges process, outside the graphite film, it is also obtained a series of spatial formation composed of carbon atoms fullerenes type which are responsible for the phenomenon of addition of mass.

Visual training improves underwater vision in children.

PubMed

Gislén, Anna; Warrant, Eric J; Dacke, Marie; Kröger, Ronald H H

2006-10-01

Children in a tribe of sea-gypsies from South-East Asia have been found to have superior underwater vision compared to European children. In this study, we show that the improved underwater vision of these Moken children is not due to better contrast sensitivity in general. We also show that European children can achieve the same underwater acuity as the Moken children. After 1 month of underwater training (11 sessions) followed by 4 months with no underwater activities, European children showed improved underwater vision and distinct bursts of pupil constriction. When tested 8 months after the last training session in an outdoor pool in bright sunlight-comparable to light environments in South-East Asia-the children had attained the same underwater acuity as the sea-gypsy children. The achieved performance can be explained by the combined effect of pupil constriction and strong accommodation.

An Underwater Color Image Quality Evaluation Metric.

PubMed

Yang, Miao; Sowmya, Arcot

2015-12-01

Quality evaluation of underwater images is a key goal of underwater video image retrieval and intelligent processing. To date, no metric has been proposed for underwater color image quality evaluation (UCIQE). The special absorption and scattering characteristics of the water medium do not allow direct application of natural color image quality metrics especially to different underwater environments. In this paper, subjective testing for underwater image quality has been organized. The statistical distribution of the underwater image pixels in the CIELab color space related to subjective evaluation indicates the sharpness and colorful factors correlate well with subjective image quality perception. Based on these, a new UCIQE metric, which is a linear combination of chroma, saturation, and contrast, is proposed to quantify the non-uniform color cast, blurring, and low-contrast that characterize underwater engineering and monitoring images. Experiments are conducted to illustrate the performance of the proposed UCIQE metric and its capability to measure the underwater image enhancement results. They show that the proposed metric has comparable performance to the leading natural color image quality metrics and the underwater grayscale image quality metrics available in the literature, and can predict with higher accuracy the relative amount of degradation with similar image content in underwater environments. Importantly, UCIQE is a simple and fast solution for real-time underwater video processing. The effectiveness of the presented measure is also demonstrated by subjective evaluation. The results show better correlation between the UCIQE and the subjective mean opinion score.

The synthesis of higher oxides of alkali and alkaline earth metals in an electric discharge: Theoretical and experimental studies

NASA Technical Reports Server (NTRS)

Bell, A. T.; Sadhukhan, P.

1974-01-01

Potassium hydroxide was subjected to the products of an electrical discharge sustained in oxygen and produced both potassium peroxide and superoxide. The conversion to higher oxides was shown to strongly depend upon the particle size of KOH, the position of KOH in the discharge zone, and the operating conditions of the discharge. Similar experiments were performed with hydroxides of lithium and calcium which do not form superoxides, but are converted to peroxides. The yields of peroxides were shown to strongly depend upon the operating conditions of the discharge. The absence of superoxides and the presence of peroxides of lithium and calcium was explained from the consideration of relative thermodynamic stability of the oxides of lithium and calcium. Thermogravimetric analysis was shown to provide a more accurate means for determining the amount of KO2 than previous methods.

Influence of catalyst packing configuration on the discharge characteristics of dielectric barrier discharge reactors: A numerical investigation

NASA Astrophysics Data System (ADS)

Gadkari, Siddharth; Gu, Sai

2018-06-01

A two-dimensional numerical fluid model is developed for studying the influence of packing configurations on dielectric barrier discharge (DBD) characteristics. Discharge current profiles and time averaged electric field strength, electron number density, and electron temperature distributions are compared for the three DBD configurations, plain DBD with no packing, partially packed DBD, and fully packed DBD. The results show that a strong change in discharge behaviour occurs when a DBD is fully packed as compared to partial packing or no packing. While the average electric field strength and electron temperature of a fully packed DBD are higher relative to the other DBD configurations, the average electron density is substantially lower and may impede the DBD reactor performance under certain operating conditions. Possible scenarios of the synergistic effect of the combination of plasma with catalysis are also discussed.

Optimal Scheduling for Underwater Communications in Multiple-user Scenarios

DTIC Science & Technology

2014-09-30

underwater acoustic sensor networks . These techniques aim at consuming as less energy as... underwater acoustic networks disrupt the behavior of surrounding species of marine mammals. As a consequence of these two studies, we aim at developing...Markov models of incremental redundancy hybrid ARQ over underwater acoustic channels. Elsevier Journal on Ad-hoc Networks (Special Issue on Underwater Communications and Networks ), 2014. 4

Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and Navigation Support

DTIC Science & Technology

2014-09-30

underwater acoustic communication technologies for autonomous distributed underwater networks , through innovative signal processing, coding, and...4. TITLE AND SUBTITLE Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and...coding: 3) OFDM modulated dynamic coded cooperation in underwater acoustic channels; 3 Localization, Networking , and Testbed: 4) On-demand

Electrical Breakdown in Water Vapor

NASA Astrophysics Data System (ADS)

Škoro, N.; Marić, D.; Malović, G.; Graham, W. G.; Petrović, Z. Lj.

2011-11-01

In this paper investigations of the voltage required to break down water vapor are reported for the region around the Paschen minimum and to the left of it. In spite of numerous applications of discharges in biomedicine, and recent studies of discharges in water and vapor bubbles and discharges with liquid water electrodes, studies of the basic parameters of breakdown are lacking. Paschen curves have been measured by recording voltages and currents in the low-current Townsend regime and extrapolating them to zero current. The minimum electrical breakdown voltage for water vapor was found to be 480 V at a pressure times electrode distance (pd) value of around 0.6 Torr cm (˜0.8 Pa m). The present measurements are also interpreted using (and add additional insight into) the developing understanding of relevant atomic and particularly surface processes associated with electrical breakdown.

2D laser-collision induced fluorescence in low-pressure argon discharges

DOE PAGES

Barnat, E. V.; Weatherford, B. R.

2015-09-25

Development and application of laser-collision induced fluorescence (LCIF) diagnostic technique is presented for the use of interrogating argon plasma discharges. Key atomic states of argon utilized for the LCIF method are identified. A simplified two-state collisional radiative model is then used to establish scaling relations between the LCIF, electron density, and reduced electric fields ( E/N). The procedure used to generate, detect and calibrate the LCIF in controlled plasma environments is discussed in detail. LCIF emanating from an argon discharge is then presented for electron densities spanning 10 9 e cm –3 to 10 12 e cm –3 and reducedmore » electric fields spanning 0.1 Td to 40 Td. Lastly, application of the LCIF technique for measuring the spatial distribution of both electron densities and reduced electric field is demonstrated.« less

Source of electrical power for an electric vehicle and other purposes, and related methods

DOEpatents

LaFollette, Rodney M.

2000-05-16

Microthin sheet technology is disclosed by which superior batteries are constructed which, among other things, accommodate the requirements for high load rapid discharge and recharge, mandated by electric vehicle criteria. The microthin sheet technology has process and article overtones and can be used to form thin electrodes used in batteries of various kinds and types, such as spirally-wound batteries, bipolar batteries, lead acid batteries, silver/zinc batteries, and others. Superior high performance battery features include: (a) minimal ionic resistance; (b) minimal electronic resistance; (c) minimal polarization resistance to both charging and discharging; (d) improved current accessibility to active material of the electrodes; (e) a high surface area to volume ratio; (f) high electrode porosity (microporosity); (g) longer life cycle; (h) superior discharge/recharge characteristics; (j) higher capacities (A.multidot.hr); and k) high specific capacitance.

Source of electrical power for an electric vehicle and other purposes, and related methods

DOEpatents

LaFollette, Rodney M.

2002-11-12

Microthin sheet technology is disclosed by which superior batteries are constructed which, among other things, accommodate the requirements for high load rapid discharge and recharge, mandated by electric vehicle criteria. The microthin sheet technology has process and article overtones and can be used to form corrugated thin electrodes used in batteries of various kinds and types, such as spirally-wound batteries, bipolar batteries, lead acid batteries, silver/zinc batteries, and others. Superior high performance battery features include: (a) minimal ionic resistance; (b) minimal electronic resistance; (c) minimal polarization resistance to both charging and discharging; (d) improved current accessibility to active material of the electrodes; (e) a high surface area to volume ratio; (f) high electrode porosity (microporosity); (g) longer life cycle; (h) superior discharge/recharge characteristics; (i) higher capacities (A.multidot.hr); and (j) high specific capacitance.

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

NASA Astrophysics Data System (ADS)

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.

Platinum Nanoparticle Decorated SiO2 Microfibers as Catalysts for Micro Unmanned Underwater Vehicle Propulsion.

PubMed

Chen, Bolin; Garland, Nathaniel T; Geder, Jason; Pruessner, Marius; Mootz, Eric; Cargill, Allison; Leners, Anne; Vokshi, Granit; Davis, Jacob; Burns, Wyatt; Daniele, Michael A; Kogot, Josh; Medintz, Igor L; Claussen, Jonathan C

2016-11-16

Micro unmanned underwater vehicles (UUVs) need to house propulsion mechanisms that are small in size but sufficiently powerful to deliver on-demand acceleration for tight radius turns, burst-driven docking maneuvers, and low-speed course corrections. Recently, small-scale hydrogen peroxide (H 2 O 2 ) propulsion mechanisms have shown great promise in delivering pulsatile thrust for such acceleration needs. However, the need for robust, high surface area nanocatalysts that can be manufactured on a large scale for integration into micro UUV reaction chambers is still needed. In this report, a thermal/electrical insulator, silicon oxide (SiO 2 ) microfibers, is used as a support for platinum nanoparticle (PtNP) catalysts. The mercapto-silanization of the SiO 2 microfibers enables strong covalent attachment with PtNPs, and the resultant PtNP-SiO 2 fibers act as a robust, high surface area catalyst for H 2 O 2 decomposition. The PtNP-SiO 2 catalysts are fitted inside a micro UUV reaction chamber for vehicular propulsion; the catalysts can propel a micro UUV for 5.9 m at a velocity of 1.18 m/s with 50 mL of 50% (w/w) H 2 O 2 . The concomitance of facile fabrication, economic and scalable processing, and high performance-including a reduction in H 2 O 2 decomposition activation energy of 40-50% over conventional material catalysts-paves the way for using these nanostructured microfibers in modern, small-scale underwater vehicle propulsion systems.

Method and apparatus for electrical cable testing by pulse-arrested spark discharge

DOEpatents

Barnum, John R.; Warne, Larry K.; Jorgenson, Roy E.; Schneider, Larry X.

2005-02-08

A method for electrical cable testing by Pulse-Arrested Spark Discharge (PASD) uses the cable response to a short-duration high-voltage incident pulse to determine the location of an electrical breakdown that occurs at a defect site in the cable. The apparatus for cable testing by PASD includes a pulser for generating the short-duration high-voltage incident pulse, at least one diagnostic sensor to detect the incident pulse and the breakdown-induced reflected and/or transmitted pulses propagating from the electrical breakdown at the defect site, and a transient recorder to record the cable response. The method and apparatus are particularly useful to determine the location of defect sites in critical but inaccessible electrical cabling systems in aging aircraft, ships, nuclear power plants, and industrial complexes.

Analysis of Electric Vehicle DC High Current Conversion Technology

NASA Astrophysics Data System (ADS)

Yang, Jing; Bai, Jing-fen; Lin, Fan-tao; Lu, Da

2017-05-01

Based on the background of electric vehicles, it is elaborated the necessity about electric energy accurate metering of electric vehicle power batteries, and it is analyzed about the charging and discharging characteristics of power batteries. It is needed a DC large current converter to realize accurate calibration of power batteries electric energy metering. Several kinds of measuring methods are analyzed based on shunts and magnetic induction principle in detail. It is put forward power batteries charge and discharge calibration system principle, and it is simulated and analyzed ripple waves containing rate and harmonic waves containing rate of power batteries AC side and DC side. It is put forward suitable DC large current measurement methods of power batteries by comparing different measurement principles and it is looked forward the DC large current measurement techniques.

A study on prevention of an electric discharge at an extraction electrode of an electron cyclotron resonance ion source for cancer therapy.

PubMed

Kishii, Y; Kawasaki, S; Kitagawa, A; Muramatsu, M; Uchida, T

2014-02-01

A compact ECR ion source has utilized for carbon radiotherapy. In order to increase beam intensity with higher electric field at the extraction electrode and be better ion supply stability for long periods, electric geometry and surface conditions of an extraction electrode have been studied. Focusing attention on black deposited substances on the extraction electrode, which were observed around the extraction electrode after long-term use, the relation between black deposited substances and the electrical insulation property is investigated. The black deposited substances were inspected for the thickness of deposit, surface roughness, structural arrangement examined using Raman spectroscopy, and characteristics of electric discharge in a test bench, which was set up to simulate the ECR ion source.

Simultaneous adaptation to size, distance, and curvature underwater.

PubMed

Vernoy, M W

1989-02-01

Perceptual adaptation to underwater size, distance, and curvature distortion was measured for four different adaptation conditions. These conditions consisted of (a) playing Chinese checkers underwater, (b) swimming with eyes open underwater, (c) viewing a square underwater, and (d) an air control. Significant adaptation to underwater distortions was recorded in all except the air control condition. In the viewing square condition a positive correlation between size and distance adaptation was noted. It was suggested that adaptation to curvature may have mediated the positive correlation. Possible applications for the training of divers are discussed.

Development of a real time monitor and multivariate method for long term diagnostics of atmospheric pressure dielectric barrier discharges: application to He, He/N2, and He/O2 discharges.

PubMed

O'Connor, N; Milosavljević, V; Daniels, S

2011-08-01

In this paper we present the development and application of a real time atmospheric pressure discharge monitoring diagnostic. The software based diagnostic is designed to extract latent electrical and optical information associated with the operation of an atmospheric pressure dielectric barrier discharge (APDBD) over long time scales. Given that little is known about long term temporal effects in such discharges, the diagnostic methodology is applied to the monitoring of an APDBD in helium and helium with both 0.1% nitrogen and 0.1% oxygen gas admixtures over periods of tens of minutes. Given the large datasets associated with the experiments, it is shown that this process is much expedited through the novel application of multivariate correlations between the electrical and optical parameters of the corresponding chemistries which, in turn, facilitates comparisons between each individual chemistry also. The results of these studies show that the electrical and optical parameters of the discharge in helium and upon the addition of gas admixtures evolve over time scales far longer than the gas residence time and have been compared to current modelling works. It is envisaged that the diagnostic together with the application of multivariate correlations will be applied to rapid system identification and prototyping in both experimental and industrial APDBD systems in the future.

AURP: An AUV-Aided Underwater Routing Protocol for Underwater Acoustic Sensor Networks

PubMed Central

Yoon, Seokhoon; Azad, Abul K.; Oh, Hoon; Kim, Sunghwan

2012-01-01

Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved. PMID:22438740

AURP: an AUV-aided underwater routing protocol for underwater acoustic sensor networks.

PubMed

Yoon, Seokhoon; Azad, Abul K; Oh, Hoon; Kim, Sunghwan

2012-01-01

Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved.

Nanosecond Plasma Enhanced H2/O2/N2 Premixed Flat Flames

DTIC Science & Technology

2014-01-01

Simulations are conducted with a one-dimensional, multi-scale, pulsed -discharge model with detailed plasma-combustion kinetics to develop additional insight... model framework. The reduced electric field, E/N, during each pulse varies inversely with number density. A significant portion of the input energy is...dimensional numerical model [4, 12] capable of resolving electric field transients over nanosecond timescales (during each discharge pulse ) and radical

The prevention of electrical breakdown and electrostatic voltage problems in the space shuttle and its payloads. Part 1: Theory and phenomena

NASA Technical Reports Server (NTRS)

Whitson, D. W.

1975-01-01

An introduction to the theory of corona discharge and electrostatic phenomena is presented. The theory is mainly qualitative so that workers in the field should not have to go outside this manual for an understanding of the relevant phenomena. Some of the problems that may occur with the space shuttle in regard to electrical discharge are discussed.

Optically triggered fire set/detonator system

DOEpatents

Chase, Jay B.; Pincosy, Philip A.; Chato, Donna M.; Kirbie, Hugh; James, Glen F.

2007-03-20

The present invention is directed to a system having a plurality of capacitor discharge units (CDUs) that includes electrical bridge type detonators operatively coupled to respective explosives. A pulse charging circuit is adapted to provide a voltage for each respective capacitor in each CDU. Such capacitors are discharged through the electrical bridge type detonators upon receiving an optical signal to detonate respective operatively coupled explosives at substantially the same time.

Surface structuring of boron doped CVD diamond by micro electrical discharge machining

NASA Astrophysics Data System (ADS)

Schubert, A.; Berger, T.; Martin, A.; Hackert-Oschätzchen, M.; Treffkorn, N.; Kühn, R.

2018-05-01

Boron doped diamond materials, which are generated by Chemical Vapor Deposition (CVD), offer a great potential for the application on highly stressed tools, e. g. in cutting or forming processes. As a result of the CVD process rough surfaces arise, which require a finishing treatment in particular for the application in forming tools. Cutting techniques such as milling and grinding are hardly applicable for the finish machining because of the high strength of diamond. Due to its process principle of ablating material by melting and evaporating, Electrical Discharge Machining (EDM) is independent of hardness, brittleness or toughness of the workpiece material. EDM is a suitable technology for machining and structuring CVD diamond, since boron doped CVD diamond is electrically conductive. In this study the ablation characteristics of boron doped CVD diamond by micro electrical discharge machining are investigated. Experiments were carried out to investigate the influence of different process parameters on the machining result. The impact of tool-polarity, voltage and discharge energy on the resulting erosion geometry and the tool wear was analyzed. A variation in path overlapping during the erosion of planar areas leads to different microstructures. The results show that micro EDM is a suitable technology for finishing of boron doped CVD diamond.

Development of battery management system for nickel-metal hydride batteries in electric vehicle applications

NASA Astrophysics Data System (ADS)

Jung, Do Yang; Lee, Baek Haeng; Kim, Sun Wook

Electric vehicle (EV) performance is very dependent on traction batteries. For developing electric vehicles with high performance and good reliability, the traction batteries have to be managed to obtain maximum performance under various operating conditions. Enhancement of battery performance can be accomplished by implementing a battery management system (BMS) that plays an important role in optimizing the control mechanism of charge and discharge of the batteries as well as monitoring the battery status. In this study, a BMS has been developed for maximizing the use of Ni-MH batteries in electric vehicles. This system performs several tasks: the control of charging and discharging, overcharge and over-discharge protection, the calculation and display of state-of-charge (SOC), safety, and thermal management. The BMS is installed in and tested in a DEV5-5 electric vehicle developed by Daewoo Motor Co. and the Institute for Advanced Engineering in Korea. Eighteen modules of a Panasonic nickel-metal hydride (Ni-MH) battery, 12 V, 95 A h, are used in the DEV5-5. High accuracy within a range of 3% and good reliability are obtained. The BMS can also improve the performance and cycle-life of the Ni-MH battery peak, as well as the reliability and the safety of the electric vehicles.

Infrastructure for thulium-170 isotope power systems for autonomous underwater vehicle fleets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walter, C.E.

1991-07-01

The radioisotope thulium-170 is a safe and environmentally benign heat source for providing the high endurance and energy densities needed by advanced power systems for autonomous underwater vehicles (AUV). Thulium Isotope Power (TIP) systems have an endurance of {approximately}3000 h, and gravimetric and volumetric energy densities of 3 {times} 10{sup 4} Wh/kg and 3 {times} 10{sup 8} Wh/m{sup 3}, respectively. These energy densities are more than 200 times higher than those currently provided by Ag-Zn battery technology. In order to capitalize on these performance levels with about one hundred AUVs in continuous use, it will be necessary to establish anmore » infrastructure for isotope production and heat-source refurbishment. The infrastructure cost is not trivial, and studies are needed to determine its optimum configuration. The major component of the projected infrastructure is the nuclear reactor used to produce Tm- 170 by neutron absorption in Tm-169. The reactor design should ideally be optimized for TM-170 production. Using the byproduct waste'' heat beneficially would help defray the cost of isotope production. However, generating electric power with the reactor would compromise both the cost of electricity and the isotope production capacity. A coastal location for the reactor would be most convenient from end-use considerations, and the waste'' heat could be used to desalinate seawater in water-thirsty states. 13 refs., 6 figs., 2 tabs.« less

Modelling of streamer ignition and propagation in the system of two approaching hydrometeors

NASA Astrophysics Data System (ADS)

Jansky, J.; Pasko, V. P.

2017-12-01

The lightning initiation in low thundercloud fields represents an unsolved problem in lightning discharge physics. One of the initial conditions required for formation of a hot leader channel is initiation of non-thermal streamer discharges. Streamers can be initiated from electron avalanches, however, the problem of existence of an electric field strong enough for streamer initiation in thunderclouds is still open. The maximum electric field in thunderstorms measured by balloons is typically 3-4 kV cm-1 atm-1, that is significantly smaller than the breakdown electric field needed for avalanche multiplication of electrons Ek≃28.7 kV cm-1 atm-1. One of the possible explanations for the streamer corona initiation is that hydrometeors greatly intensify the local electric field by at least an order of magnitude to initiate an electron avalanche. It was suggested that a particle pair or chain create more favorable conditions for initiation of lightning discharge than a single precipitation particle in low electric fields. Recently Cai et al. [GRL, 44, 5758-5765, 2017] analyzed the ignition conditions for two hydrometeors of same radii. In the present work we use streamer fluid model to study streamer initiation scenarios in a system of two hydrometeors with different radii. When the hydrometeors are approaching the Townsend discharge may develop first between them. Then the Townsend discharge transforms to streamer and two hydrometeors connect electrically, which leads to increase of the electric field on the outside hemispheres of hydrometeors. This increase of field for two particles of same radii was analyzed by Cooray et al. [Proceedings of 24th International Conference on Lightning Protection, Birmingham, United Kingdom, 1998]. The combination of small and large hydrometeors leads to higher enhancement on the outside of small hydrometeor. Simulation results show that streamer ignites there and propagates away from two hydrometeors. The streamer ignites at fields below Meek criterion due to the effects of photoionization feedback [Naidis, JPD, 38, 2211-2214, 2005; Liu et al., JASTP, 80, 179-186, 2012].

HV discharge acceleration by sequences of UV laser filaments with visible and near-infrared pulses

NASA Astrophysics Data System (ADS)

Schubert, Elise; Rastegari, Ali; Feng, Chengyong; Mongin, Denis; Kamer, Brian; Kasparian, Jérôme; Wolf, Jean-Pierre; Arissian, Ladan; Diels, Jean-Claude

2017-12-01

We investigate the triggering and guiding of DC high-voltage discharges over a distance of 37 cm by filaments produced by ultraviolet (266 nm) laser pulses of 200 ps duration. The latter reduce the breakdown electric field by half and allow up to 80% discharge probability in an electric field of 920 kV m–1. This high efficiency is not further increased by adding nanosecond pulses in the Joule range at 532 and at 1064 nm. However, the latter statistically increases the guiding length, thereby accelerating the discharge by a factor of 2. This effect is due both to photodetachment and to the heating of the plasma channel, that increases the efficiency of avalanche ionization and reduces electron attachment and recombination.

Distribution of E/N and N sub e in a cross-flow electric discharge laser

NASA Technical Reports Server (NTRS)

Dunning, J. W., Jr.; Lancashire, R. B.; Manista, E. J.

1976-01-01

The spatial distribution of the ratio of electric field to neutral gas density on a flowing gas, multiple pin-to-plane discharge was measured in a high-power, closed loop laser. The laser was operated at a pressure of 140 torr (1:7:20, CO2, N2, He) with typically a 100 meter/second velocity in the 5 x 8 x 135 centimeter discharge volume. E/N ratios ranged from 2.7 x 10 to the minus 16th power to 1.4 x 10 to the minus 16th power volts/cu cm along the discharge while the electron density ranged from 2.8 x 10 to the 10th power to 1.2 x 10 to the 10th power cm/3.

Method of minimizing the effects of parasitic currents

DOEpatents

Chi, Michael C.; Carr, Peter

1983-02-01

A method of minimizing the effect of parasitic currents in secondary batteries having a plurality of cells connected electrically in series and a common electrolyte in communication with the cells is described. Specifically, the parasitic currents flowing through the battery cause a cell imbalance over the charge/discharge cycle. This cell imbalance is minimized by first separating the cells of the battery into two equal groups. Then the battery is charged with the two groups of cells connected electrically in series, and subsequently discharged with the two groups of cells reconnected electrically in series in an inverted sequence.

Method for forming precision clockplate with pivot pins

DOEpatents

Wild, Ronald L [Albuquerque, NM

2010-06-01

Methods are disclosed for producing a precision clockplate with rotational bearing surfaces (e.g. pivot pins). The methods comprise providing an electrically conductive blank, conventionally machining oversize features comprising bearing surfaces into the blank, optionally machining of a relief on non-bearing surfaces, providing wire accesses adjacent to bearing surfaces, threading the wire of an electrical discharge machine through the accesses and finishing the bearing surfaces by wire electrical discharge machining. The methods have been shown to produce bearing surfaces of comparable dimension and tolerances as those produced by micro-machining methods such as LIGA, at reduced cost and complexity.

Gas ion laser construction for electrically isolating the pressure gauge thereof

NASA Technical Reports Server (NTRS)

Wood, C. E.; Witte, R. S. (Inventor)

1975-01-01

The valve and the pressure gauge of a gas ion laser were electrically insulated from the laser discharge path by connecting them in series with the cathode of the laser. The laser cathode can be grounded and preferably is a cold cathode although a hot cathode may be used instead. The cold cathode was provided with a central aperture to which was connected both the pressure gauge and the gas pressure reservoir through the valve. This will effectively prevent electric discharges from passing either to the pressure gauge or the valve which would otherwise destroy the pressure gauge.

Measurement and modeling of electric field and space-charge distributions in obstructed helium discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fendel, Peter; Ganguly, Biswa N.; Bletzinger, Peter

Axial and radial variations of electric field have been measured in dielectric shielded 0.025 m diameter parallel plate electrode with 0.0065 m gap for 1.6 mA, 2260 V helium dc discharge at 1.75 Torr. The axial and radial electric field profiles have been measured from the Stark splitting of 2{sup 1}S→11 {sup 1}P transition through collision induced fluorescence from 4{sup 3}D→2{sup 3}P. The electric field values showed a strong radial variation peaking to 500 kV/m near the cathode radial boundary, and decreasing to about 100 kV/m near the anode edge, suggesting the formation of an obstructed discharge for this low nd condition, where n is the gasmore » density and d is the gap distance. The off-axis Stark spectra showed that the electric field vector deviates from normal to the cathode surface which permits longer path electron trajectories in the inter-electrode gap. Also, the on-axis electric field gradient was very small and off-axis electric field gradient was large indicating a radially non-uniform current density. In order to obtain information about the space charge distribution in this obstructed discharge, it was modeled using the 2-d axisymmetric Poisson solver with the COMSOL finite element modeling program. The best fit to the measured electric field distribution was obtained with a space charge variation of ρ(r) = ρ{sub 0}(r/r{sub 0}){sup 3}, where ρ(r) is the local space charge density, ρ{sub 0} = 6 × 10{sup −3} Coulomb/m{sup 3}, r is the local radial value, and r{sub 0} is the radius of the electrode.« less

Indirect determination of the electric field in plasma discharges using laser-induced fluorescence spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vaudolon, J., E-mail: julien.vaudolon@cnrs-orleans.fr; Mazouffre, S., E-mail: stephane.mazouffre@cnrs-orleans.fr

2014-09-15

The evaluation of electric fields is of prime interest for the description of plasma characteristics. In this work, different methods for determining the electric field profile in low-pressure discharges using one- and two-dimensional Laser-Induced Fluorescence (LIF) measurements are presented and discussed. The energy conservation, fluid, and kinetic approaches appear to be well-suited for the electric field evaluation in this region of the plasma flow. However, the numerical complexity of a two-dimensional kinetic model is penalizing due to the limited signal-to-noise ratio that can be achieved, making the computation of the electric field subject to large error bars. The ionization contributionmore » which appears in the fluid model makes it unattractive on an experimental viewpoint. The energy conservation and 1D1V kinetic approaches should therefore be preferred for the determination of the electric field when LIF data are used.« less

Effect of the radio frequency discharge on the dust charging process in a weakly collisional and fully ionized plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Motie, Iman; Bokaeeyan, Mahyar, E-mail: Mehyar9798@gmail.com

2015-02-15

A close analysis of dust charging process in the presence of radio frequency (RF) discharge on low pressure and fully ionized plasma for both weak and strong discharge's electric field is considered. When the electromagnetic waves pass throughout fully ionized plasma, the collision frequency of the plasma is derived. Moreover, the disturbed distribution function of plasma particles in the presence of the RF discharge is obtained. In this article, by using the Krook model, we separate the distribution function in two parts, the Maxwellian part and the perturbed part. The perturbed part of distribution can make an extra current, so-calledmore » the accretion rate of electron (or ion) current, towards a dust particle as a function of the average electron-ion collision frequency. It is proven that when the potential of dust grains increases, the accretion rate of electron current experiences an exponential reduction. Furthermore, the accretion rate of electron current for a strong electric field is relatively smaller than that for a weak electric field. The reasons are elaborated.« less

A semi-analytical study of positive corona discharge in wire-plane electrode configuration

NASA Astrophysics Data System (ADS)

Yanallah, K.; Pontiga, F.; Chen, J. H.

2013-08-01

Wire-to-plane positive corona discharge in air has been studied using an analytical model of two species (electrons and positive ions). The spatial distributions of electric field and charged species are obtained by integrating Gauss's law and the continuity equations of species along the Laplacian field lines. The experimental values of corona current intensity and applied voltage, together with Warburg's law, have been used to formulate the boundary condition for the electron density on the corona wire. To test the accuracy of the model, the approximate electric field distribution has been compared with the exact numerical solution obtained from a finite element analysis. A parametrical study of wire-to-plane corona discharge has then been undertaken using the approximate semi-analytical solutions. Thus, the spatial distributions of electric field and charged particles have been computed for different values of the gas pressure, wire radius and electrode separation. Also, the two dimensional distribution of ozone density has been obtained using a simplified plasma chemistry model. The approximate semi-analytical solutions can be evaluated in a negligible computational time, yet provide precise estimates of corona discharge variables.

Internal Electrostatic Discharge Monitor - IESDM

NASA Technical Reports Server (NTRS)

Kim, Wousik; Goebel, Dan M.; Jun, Insoo; Garrett, Henry B.

2011-01-01

A document discusses an innovation designed to effectively monitor dielectric charging in spacecraft components to measure the potential for discharge in order to prevent damage from internal electrostatic discharge (IESD). High-energy electrons penetrate the structural materials and shielding of a spacecraft and then stop inside dielectrics and keep accumulating. Those deposited charges generate an electric field. If the electric field becomes higher than the breakdown threshold (approx. =2 x 10(exp 5) V/cm), discharge occurs. This monitor measures potentials as a function of dielectric depth. Differentiation of potential with respect to the depth yields electric field. Direct measurement of the depth profile of the potential in a dielectric makes real-time electronic field evaluation possible without simulations. The IESDM has been designed to emulate a multi-layer circuit board, to insert very thin metallic layers between the dielectric layers. The conductors serve as diagnostic monitoring locations to measure the deposited electron-charge and the charge dynamics. Measurement of the time-dependent potential of the metal layers provides information on the amount of charge deposited in the dielectrics and the movement of that charge with time (dynamics).

Carbon-based nanomaterial synthesis using nanosecond electrical discharges in immiscible layered liquids: n-heptane and water

NASA Astrophysics Data System (ADS)

Hamdan, Ahmad; Cha, Min Suk

2018-06-01

Plasmas in- or in-contact with liquids have been extensively investigated due to their high potential for a wide range of applications including, but not limited to, water treatment, material synthesis and functionalization, bio-medical applications, and liquid fuel reformation. Recently, we successfully developed a discharge using two immiscible liquids, having very different electrical permittivities, which could significantly intensify the electric field intensity. Here, we establish nanosecond discharges at the interface n-heptane-water (with respective relative dielectric permittivities of 2 and 80) to enable the synthesis of carbon-based nanomaterials. A characterization of the as-synthesized material and the annealed (500 °C) material, using various techniques (Fourier-transform, infra-red, scanning and transmission electron microscopes, etc), shows that the as-synthesized material is a mixture of two carbon-based phases: a crystalline phase (graphite like) embedded into a phase of hydrogenated amorphous carbon. The existence of two-phases may be explained by the non-homogeneity of the discharge that induces various chemical reactions in the plasma channel.

A comparative study on the frequency effects of the electrical characteristics of the pulsed dielectric barrier discharge in He/O{sub 2} and in Ar/O{sub 2} at atmospheric pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Guangsheng; Tan, Zhenyu, E-mail: tzy@sdu.edu.cn; Pan, Jie

In this work, a comparative study on the frequency effects of the electrical characteristics of the pulsed dielectric barrier discharges in He/O{sub 2} and in Ar/O{sub 2} at atmospheric pressure has been performed by means of the numerical simulation based on a 1-D fluid model at frequencies below 100 kHz. The frequency dependences of the characteristic quantities of the discharges in the two gases have been systematically calculated and analyzed under the oxygen concentrations below 2%. The characteristic quantities include the discharge current density, the averaged electron density, the electric field, and the averaged electron temperature. Especially, the frequency effects onmore » the averaged particle densities of the reactive species have also been calculated. This work gives the following significant results. For the two gases, there are two bipolar discharges in one period of applied voltage pulse under the considered frequency range and oxygen concentrations, as occurred in the pure noble gases. The frequency affects the two discharges in He/O{sub 2}, but in Ar/O{sub 2}, it induces a strong effect only on the first discharge. For the first discharge in each gas, there is a characteristic frequency at which the characteristic quantities reach their respective minimum, and this frequency appears earlier for Ar/O{sub 2}. For the second discharge in Ar/O{sub 2}, the averaged electron density presents a slight variation with the frequency. In addition, the discharge in Ar/O{sub 2} is strong and the averaged electron temperature is low, compared to those in He/O{sub 2.} The total averaged particle density of the reactive species in Ar/O{sub 2} is larger than those in He/O{sub 2} by about one order of magnitude.« less

Vehicle Based Vector Sensor

DTIC Science & Technology

2015-09-28

buoyant underwater vehicle with an interior space in which a length of said underwater vehicle is equal to one tenth of the acoustic wavelength...underwater vehicle with an interior space in which a length of said underwater vehicle is equal to one tenth of the acoustic wavelength; an...unmanned underwater vehicle that can function as an acoustic vector sensor. (2) Description of the Prior Art [0004] It is known that a propagating

THE NATURE OF ENERGY TRANSFER TO ELECTRODES IN A PULSE DISCHARGE WITH SMALL GAPS,

DTIC Science & Technology

SPARK MACHINING, ELECTRIC DISCHARGES), (*ELECTROMAGNETIC PULSES, SPARK MACHINING), ELECTROEROSIVE MACHINING, ENERGY, ELECTRON IRRADIATION, ION BOMBARDMENT, THERMAL CONDUCTIVITY, FILMS, KINETIC ENERGY, ZONE MELTING, USSR

System and method for altering characteristics of materials using an electrohydraulic discharge

DOEpatents

Banerjee, Sujit

2003-06-03

System and method for oxidizing contaminants to alter specific properties, such as tack, of contaminants. The present invention reduces the tack of the stickies and pitch by exposing the materials for a short duration to low-energy pulsed electrical discharges between a pair of electrodes that are submerged in a liquid medium, such as a fiber stream, water, a pulp slurry, or whitewater. An electrical discharge in the liquid medium oxidizes materials, which may be dissolved or suspended therein, such as stickies, pitch, sulfide, ink, toner, and other substances, thereby reducing tack, odor, and/or zeta potential, as well as producing other desirable effect.

ION SOURCE

DOEpatents

Blue, C.W.; Luce, J.S.

1960-07-19

An ion source is described and comprises an arc discharge parallel to the direction of and inside of a magnetic field. an accelerating electrode surrounding substantially all of the discharge except for ion exit apertures, and means for establishing an electric field between that electrode and the arc discharge. the electric field being oriented at an acute angle to the magnetic field. Ions are drawn through the exit apertures in the accelrating electrcde in a direction substantially divergent to the direction of the magnetic field and so will travel in a spiral orbit along the magnetic field such that the ions will not strike the source at any point in their orbit within the magnetic field.

Critical analysis of active methods of ozone layer recovery

NASA Astrophysics Data System (ADS)

Bekker, S. Z.; Doronin, A. P.; Kozlov, S. I.

2017-09-01

A critical analysis is given for various methods for recovery of the ozone layer of the Earth: the emission of alkane gases, the destruction of freons by laser IR radiation and with microwave discharge, exposure to laser UV radiation and electric discharge in the atmosphere, the use of solar radiation, laser infrared radiation, and gamma rays, and the creation of an artificial formation at high altitudes that shields the solar radiation dissociating ozone. The optimal methods are discussed in terms of their effectiveness, economic costs, and environmental consequences. These include the use of gamma rays sources, electric discharge in the atmosphere, and microwave breakdown.

Influence of air humidity and the distance from the source on negative air ion concentration in indoor air.

PubMed

Wu, Chih Cheng; Lee, Grace W M; Yang, Shinhao; Yu, Kuo-Pin; Lou, Chia Ling

2006-10-15

Although negative air ionizer is commonly used for indoor air cleaning, few studies examine the concentration gradient of negative air ion (NAI) in indoor environments. This study investigated the concentration gradient of NAI at various relative humidities and distances form the source in indoor air. The NAI was generated by single-electrode negative electric discharge; the discharge was kept at dark discharge and 30.0 kV. The NAI concentrations were measured at various distances (10-900 cm) from the discharge electrode in order to identify the distribution of NAI in an indoor environment. The profile of NAI concentration was monitored at different relative humidities (38.1-73.6% RH) and room temperatures (25.2+/-1.4 degrees C). Experimental results indicate that the influence of relative humidity on the concentration gradient of NAI was complicated. There were four trends for the relationship between NAI concentration and relative humidity at different distances from the discharge electrode. The changes of NAI concentration with an increase in relative humidity at different distances were quite steady (10-30 cm), strongly declining (70-360 cm), approaching stability (420-450 cm) and moderately increasing (560-900 cm). Additionally, the regression analysis of NAI concentrations and distances from the discharge electrode indicated a logarithmic linear (log-linear) relationship; the distance of log-linear tendency (lambda) decreased with an increase in relative humidity such that the log-linear distance of 38.1% RH was 2.9 times that of 73.6% RH. Moreover, an empirical curve fit based on this study for the concentration gradient of NAI generated by negative electric discharge in indoor air was developed for estimating the NAI concentration at different relative humidities and distances from the source of electric discharge.

Atmospheric-pressure diffuse dielectric barrier discharges in Ar/O2 gas mixture using 200 kHz/13.56 MHz dual frequency excitation

NASA Astrophysics Data System (ADS)

Liu, Y.; Starostin, S. A.; Peeters, F. J. J.; van de Sanden, M. C. M.; de Vries, H. W.

2018-03-01

Atmospheric-pressure diffuse dielectric barrier discharges (DBDs) were obtained in Ar/O2 gas mixture using dual-frequency (DF) excitation at 200 kHz low frequency (LF) and 13.56 MHz radio frequency (RF). The excitation dynamics and the plasma generation mechanism were studied by means of electrical characterization and phase resolved optical emission spectroscopy (PROES). The DF excitation results in a time-varying electric field which is determined by the total LF and RF gas voltage and the spatial ion distribution which only responds to the LF component. By tuning the amplitude ratio of the superimposed LF and RF signals, the effect of each frequency component on the DF discharge mechanism was analysed. The LF excitation results in a transient plasma with the formation of an electrode sheath and therefore a pronounced excitation near the substrate. The RF oscillation allows the electron trapping in the gas gap and helps to improve the plasma uniformity by contributing to the pre-ionization and by controlling the discharge development. The possibility of temporally modifying the electric field and thus the plasma generation mechanism in the DF discharge exhibits potential applications in plasma-assisted surface processing and plasma-assisted gas phase chemical conversion.

Inactivation of MS2 bacteriophage by streamer corona discharge in water.

PubMed

Lee, Changha; Kim, Jaeeun; Yoon, Jeyong

2011-02-01

Electrical discharge processes are emerging as water treatment technologies applicable to both the degradation of organic contaminants as well as inactivation of pathogens. Particularly as a disinfection technology, electrical discharge processes do not produce toxic byproducts, and effectively inactivate a wide spectrum of microorganisms by multiple lethal actions generated by the formation of plasma channels. This study demonstrates the inactivation of a virus using the streamer corona discharge process (SCDP) with MS2 phage as a surrogate. A rapid inactivation of MS2 phage (i.e., approximately 4 log inactivation in 5 min) was observed in all experimental runs conducted. Discharge conditions such as applied voltage and storage capacitance significantly affected the inactivation efficiency of MS2 phage, whereas the influence of water quality parameters was minor. In order to elucidate the mechanism of MS2 phage inactivation, potentially lethal factors that can be generated by the SCDP were selected, and their roles in the inactivation of MS2 phage were examined. As a result, effects of UV radiation, chemical oxidants, and pulsed electric fields were found to be insignificant. The shockwave generated upon plasma channel formation appears to be the most important factor responsible for MS2 phage inactivation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Marine electrical resistivity imaging of submarine groundwater discharge: Sensitivity analysis and application in Waquoit Bay, Massachusetts, USA

USGS Publications Warehouse

Henderson, Rory; Day-Lewis, Frederick D.; Abarca, Elena; Harvey, Charles F.; Karam, Hanan N.; Liu, Lanbo; Lane, John W.

2010-01-01

Electrical resistivity imaging has been used in coastal settings to characterize fresh submarine groundwater discharge and the position of the freshwater/salt-water interface because of the relation of bulk electrical conductivity to pore-fluid conductivity, which in turn is a function of salinity. Interpretation of tomograms for hydrologic processes is complicated by inversion artifacts, uncertainty associated with survey geometry limitations, measurement errors, and choice of regularization method. Variation of seawater over tidal cycles poses unique challenges for inversion. The capabilities and limitations of resistivity imaging are presented for characterizing the distribution of freshwater and saltwater beneath a beach. The experimental results provide new insight into fresh submarine groundwater discharge at Waquoit Bay National Estuarine Research Reserve, East Falmouth, Massachusetts (USA). Tomograms from the experimental data indicate that fresh submarine groundwater discharge may shut down at high tide, whereas temperature data indicate that the discharge continues throughout the tidal cycle. Sensitivity analysis and synthetic modeling provide insight into resolving power in the presence of a time-varying saline water layer. In general, vertical electrodes and cross-hole measurements improve the inversion results regardless of the tidal level, whereas the resolution of surface arrays is more sensitive to time-varying saline water layer.

Experimental observations of strengthening the neutron flux during negative lightning discharges of thunderclouds with tripolar configuration

NASA Astrophysics Data System (ADS)

Toropov, A. A.; Kozlov, V. I.; Mullayarov, V. A.; Starodubtsev, S. A.

2013-03-01

We consider neutron bursts (Yakutsk cosmic ray spectrograph,105 m above sea level) and the electric field during lightning discharges. It was found that the neutron bursts are observed in the negative lightning discharg only. We discuss the possibility of generation of neutrons in the lower part (the point of impact into the ground) lightning discharge.

Electric characteristics of a surface barrier discharge with a plasma induction electrode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alemskii, I. N.; Lelevkin, V. M.; Tokarev, A. V.

2006-07-15

Static and dynamic current-voltage and charge-voltage characteristics of a surface barrier discharge with a plasma induction electrode have been investigated experimentally. The dependences of the discharge current on both the gas pressure in the induction electrode tube and the winding pitch of the corona electrode, as well as of the discharge power efficiency on the applied voltage, have been measured.

Acoustic and Electrical Fields of Fish and Marine Mammals

DTIC Science & Technology

1975-05-19

dolphins Relation of electrical and acoustic signals in fish Magnetic field of the electric discharge of catfish ( Malapterurus electricus ... Malapterurus .Tectricus). IN: Voprosy gidrobioniki, Moscow, Nauka, 1974, 10-12. The authors report on their experiments with recording the

Performance, Facility Pressure Effects, and Stability Characterization Tests of NASA's Hall Effect Rocket with Magnetic Shielding Thruster

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Yim, John; Herman, Daniel; Williams, George; Gilland, James; Peterson, Peter; Hofer, Richard; Mikellides, Ioannis

2016-01-01

NASAs Hall Effect Rocket with Magnetic Shielding (HERMeS) 12.5 kW Technology Demonstration Unit-1 (TDU-1) Hall thruster has been the subject of extensive technology maturation in preparation for flight system development. Part of the technology maturation effort included experimental evaluation of the TDU-1 thruster with conducting and dielectric front pole cover materials in two different electrical configurations. A graphite front pole cover thruster configuration with the thruster body electrically tied to cathode and an alumina front pole cover thruster configuration with the thruster body floating were evaluated. Both configurations were also evaluated at different facility background pressure conditions to evaluate background pressure effects on thruster operation. Performance characterization tests found that higher thruster performance was attained with the graphite front pole cover configuration with the thruster electrically tied to cathode. A total thrust efficiency of 68 and a total specific impulse of 2,820 s was demonstrated at a discharge voltage of 600 V and a discharge power of 12.5 kW. Thruster stability regimes were characterized with respect to the thruster discharge current oscillations and with maps of the current-voltage-magnetic field (IVB). Analysis of TDU-1 discharge current waveforms found that lower normalized discharge current peak-to-peak and root mean square magnitudes were attained when the thruster was electrically floated with alumina front pole covers. Background pressure effects characterization tests indicated that the thruster performance and stability was mostly invariant to changes in the facility background pressure for vacuum chamber pressure below 110-5 Torr-Xe (for thruster flow rate above 8 mgs). Power spectral density analysis of the discharge current waveform showed that increasing the vacuum chamber background pressure resulted in a higher discharge current dominant frequency. Finally the IVB maps of the TDU-1 thruster taken at elevated magnetic fields indicated that the discharge current became more oscillatory with increased facility background pressure at lower thruster mass flow rates, where thruster operation at higher flow rates resulted in less change to the thrusters IVB characteristics.

Spoke rotation reversal in magnetron discharges of aluminium, chromium and titanium

NASA Astrophysics Data System (ADS)

Hecimovic, A.; Maszl, C.; Schulz-von der Gathen, V.; Böke, M.; von Keudell, A.

2016-06-01

The rotation of localised ionisation zones, i.e. spokes, in magnetron discharge are frequently observed. The spokes are investigated by measuring floating potential oscillations with 12 flat probes placed azimuthally around a planar circular magnetron. The 12-probe setup provides sufficient temporal and spatial resolution to observe the properties of various spokes, such as rotation direction, mode number and angular velocity. The spokes are investigated as a function of discharge current, ranging from 10 mA (current density 0.5 mA cm-2) to 140 A (7 A cm-2). In the range from 10 mA to 600 mA the plasma was sustained in DC mode, and in the range from 1 A to 140 A the plasma was pulsed in high-power impulse magnetron sputtering mode. The presence of spokes throughout the complete discharge current range indicates that the spokes are an intrinsic property of a magnetron sputtering plasma discharge. The spokes may disappear at discharge currents above 80 A for Cr, as the plasma becomes homogeneously distributed over the racetrack. Up to discharge currents of several amperes (the exact value depends on the target material), the spokes rotate in a retrograde \\mathbf{E}× \\mathbf{B} direction with angular velocity in the range of 0.2-4 km s-1. Beyond a discharge current of several amperes, the spokes rotate in a \\mathbf{E}× \\mathbf{B} direction with angular velocity in the range of 5-15 km s-1. The spoke rotation reversal is explained by a transition from Ar-dominated to metal-dominated sputtering that shifts the plasma emission zone closer to the target. The spoke itself corresponds to a region of high electron density and therefore to a hump in the electrical potential. The electric field around the spoke dominates the spoke rotation direction. At low power, the plasma is further away from the target and it is dominated by the electric field to the anode, thus retrograde \\mathbf{E}× \\mathbf{B} rotation. At high power, the plasma is closer to the target and it is dominated by the electric field pointing to the target, thus \\mathbf{E}× \\mathbf{B} rotation.

Characteristics of edge breakdowns on Teflon samples

NASA Technical Reports Server (NTRS)

Yadlowsky, E. J.; Hazelton, R. C.; Churchill, R. J.

1980-01-01

The characteristics of electrical discharges induced on silverbacked Teflon samples irradiated by a monoenergetic electron beam have been studied under controlled laboratory conditions. Measurements of breakdown threshold voltages indicate a marked anisotropy in the electrical breakdown properties of Teflon: differences of up to 10 kV in breakdown threshold voltage are observed depending on the sample orientation. The material anisotropy can be utilized in spacecraft construction to reduce the magnitude of discharge currents.

Runaway breakdown and hydrometeors in lightning initiation.

PubMed

Gurevich, A V; Karashtin, A N

2013-05-03

The particular electric pulse discharges are observed in thunderclouds during the initiation stage of negative cloud-to-ground lightning. The discharges are quite different from conventional streamers or leaders. A detailed analysis reveals that the shape of the pulses is determined by the runaway breakdown of air in the thundercloud electric field initiated by extensive atmospheric showers (RB-EAS). The high amplitude of the pulse electric current is due to the multiple microdischarges at hydrometeors stimulated and synchronized by the low-energy electrons generated in the RB-EAS process. The series of specific pulse discharges leads to charge reset from hydrometeors to the free ions and creates numerous stretched ion clusters, both positive and negative. As a result, a wide region in the thundercloud with a sufficiently high fractal ion conductivity is formed. The charge transport by ions plays a decisive role in the lightning leader preconditioning.

Microsecond-scale electric field pulses in cloud lightning discharges

NASA Technical Reports Server (NTRS)

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.

Plasma diagnostics of non-equilibrium atmospheric plasma jets

NASA Astrophysics Data System (ADS)

Shashurin, Alexey; Scott, David; Keidar, Michael; Shneider, Mikhail

2014-10-01

Intensive development and biomedical application of non-equilibrium atmospheric plasma jet (NEAPJ) facilitates rapid growth of the plasma medicine field. The NEAPJ facility utilized at the George Washington University (GWU) demonstrated efficacy for treatment of various cancer types (lung, bladder, breast, head, neck, brain and skin). In this work we review recent advances of the research conducted at GWU concerned with the development of NEAPJ diagnostics including Rayleigh Microwave Scattering setup, method of streamer scattering on DC potential, Rogowski coils, ICCD camera and optical emission spectroscopy. These tools allow conducting temporally-resolved measurements of plasma density, electrical potential, charge and size of the streamer head, electrical currents flowing though the jet, ionization front propagation speed etc. Transient dynamics of plasma and discharge parameters will be considered and physical processes involved in the discharge will be analyzed including streamer breakdown, electrical coupling of the streamer tip with discharge electrodes, factors determining NEAPJ length, cross-sectional shape and propagation path etc.

Comparative analysis of cellulose pressboard and aramid paper used in air insulation systems of high-voltage devices

NASA Astrophysics Data System (ADS)

Turba, Tomasz; Frącz, Paweł

2017-10-01

The paper presents results of a comparative analysis of parameters of two kinds of solid dielectrics used in air insulation systems to prevent occurring partial discharges. The research works regarded materials made of: cellulose pressboard and aramid paper. All measurements were performed under laboratory conditions by changing the value of partial discharges generation voltage until breakdown occurred in the inhomogeneous environment that was simulated using needle-plate (made of copper) electrode system. The main contribution which resulted from studies is a statement that potential use of aramid paper as a dielectric can extend the life of a high voltage electric device as compared to standard cellulose pressboard usage due to higher electric resistances to breakdown or detection of corona voltage. Results shown that the aramid paper has greater electric resistance to breakdown in comparison to cellulose with no difference between both on detecting corona of partial discharge.

Discharge ignition in the diaphragm configuration supplied by DC non-pulsing voltage

NASA Astrophysics Data System (ADS)

Hlochová, L.; Hlavatá, L.; Kozáková, Z.; Krčma, F.

2016-05-01

This work deals with the ignition of the discharge in the diaphragm configuration generated in water solutions containing supporting NaCl electrolyte. The reactor has volume of 110 ml and it is made of polycarbonate. HV electrodes made of stainless steel are placed in this reactor. Ceramic (Shapal-MTM) diaphragm is placed in the barrier separating the cathode and the anode space. An electric power source supplies the reactor by constant DC voltage up to 4 kV and electric current up to 300 mA. The discharge ignition is compared in the reactor with different sizes of diaphragms. Measurements are carried out in electrolyte solutions with the same conductivity. Images of plasma streamers and bubble formation are taken by an ICCD camera iStar 734. Electrical characteristics are measured by an oscilloscope LeCroy LT 374 L in order to determine breakdown moments at different experimental conditions.

RF Path and Absorption Loss Estimation for Underwater Wireless Sensor Networks in Different Water Environments

PubMed Central

Qureshi, Umair Mujtaba; Shaikh, Faisal Karim; Aziz, Zuneera; Shah, Syed M. Zafi S.; Sheikh, Adil A.; Felemban, Emad; Qaisar, Saad Bin

2016-01-01

Underwater Wireless Sensor Network (UWSN) communication at high frequencies is extremely challenging. The intricacies presented by the underwater environment are far more compared to the terrestrial environment. The prime reason for such intricacies are the physical characteristics of the underwater environment that have a big impact on electromagnetic (EM) signals. Acoustics signals are by far the most preferred choice for underwater wireless communication. Because high frequency signals have the luxury of large bandwidth (BW) at shorter distances, high frequency EM signals cannot penetrate and propagate deep in underwater environments. The EM properties of water tend to resist their propagation and cause severe attenuation. Accordingly, there are two questions that need to be addressed for underwater environment, first what happens when high frequency EM signals operating at 2.4 GHz are used for communication, and second which factors affect the most to high frequency EM signals. To answer these questions, we present real-time experiments conducted at 2.4 GHz in terrestrial and underwater (fresh water) environments. The obtained results helped in studying the physical characteristics (i.e., EM properties, propagation and absorption loss) of underwater environments. It is observed that high frequency EM signals can propagate in fresh water at a shallow depth only and can be considered for a specific class of applications such as water sports. Furthermore, path loss, velocity of propagation, absorption loss and the rate of signal loss in different underwater environments are also calculated and presented in order to understand why EM signals cannot propagate in sea water and oceanic water environments. An optimal solk6ution for underwater communication in terms of coverage distance, bandwidth and nature of communication is presented, along with possible underwater applications of UWSNs at 2.4 GHz. PMID:27322263

Determining spherical lens correction for astronaut training underwater.

PubMed

Porter, Jason; Gibson, C Robert; Strauss, Samuel

2011-09-01

To develop a model that will accurately predict the distance spherical lens correction needed to be worn by National Aeronautics and Space Administration astronauts while training underwater. The replica space suit's helmet contains curved visors that induce refractive power when submersed in water. Anterior surface powers and thicknesses were measured for the helmet's protective and inside visors. The impact of each visor on the helmet's refractive power in water was analyzed using thick lens calculations and Zemax optical design software. Using geometrical optics approximations, a model was developed to determine the optimal distance spherical power needed to be worn underwater based on the helmet's total induced spherical power underwater and the astronaut's manifest spectacle plane correction in air. The validity of the model was tested using data from both eyes of 10 astronauts who trained underwater. The helmet's visors induced a total power of -2.737 D when placed underwater. The required underwater spherical correction (FW) was linearly related to the spectacle plane spherical correction in air (FAir): FW = FAir + 2.356 D. The mean magnitude of the difference between the actual correction worn underwater and the calculated underwater correction was 0.20 ± 0.11 D. The actual and calculated values were highly correlated (r = 0.971) with 70% of eyes having a difference in magnitude of <0.25 D between values. We devised a model to calculate the spherical spectacle lens correction needed to be worn underwater by National Aeronautics and Space Administration astronauts. The model accurately predicts the actual values worn underwater and can be applied (more generally) to determine a suitable spectacle lens correction to be worn behind other types of masks when submerged underwater.

Determining spherical lens correction for astronaut training underwater

PubMed Central

Porter, Jason; Gibson, C. Robert; Strauss, Samuel

2013-01-01

Purpose To develop a model that will accurately predict the distance spherical lens correction needed to be worn by National Aeronautics and Space Administration (NASA) astronauts while training underwater. The replica space suit’s helmet contains curved visors that induce refractive power when submersed in water. Methods Anterior surface powers and thicknesses were measured for the helmet’s protective and inside visors. The impact of each visor on the helmet’s refractive power in water was analyzed using thick lens calculations and Zemax optical design software. Using geometrical optics approximations, a model was developed to determine the optimal distance spherical power needed to be worn underwater based on the helmet’s total induced spherical power underwater and the astronaut’s manifest spectacle plane correction in air. The validity of the model was tested using data from both eyes of 10 astronauts who trained underwater. Results The helmet visors induced a total power of −2.737 D when placed underwater. The required underwater spherical correction (FW) was linearly related to the spectacle plane spherical correction in air (FAir): FW = FAir + 2.356 D. The mean magnitude of the difference between the actual correction worn underwater and the calculated underwater correction was 0.20 ± 0.11 D. The actual and calculated values were highly correlated (R = 0.971) with 70% of eyes having a difference in magnitude of < 0.25 D between values. Conclusions We devised a model to calculate the spherical spectacle lens correction needed to be worn underwater by National Aeronautics and Space Administration astronauts. The model accurately predicts the actual values worn underwater and can be applied (more generally) to determine a suitable spectacle lens correction to be worn behind other types of masks when submerged underwater. PMID:21623249

RF Path and Absorption Loss Estimation for Underwater Wireless Sensor Networks in Different Water Environments.

PubMed

Qureshi, Umair Mujtaba; Shaikh, Faisal Karim; Aziz, Zuneera; Shah, Syed M Zafi S; Sheikh, Adil A; Felemban, Emad; Qaisar, Saad Bin

2016-06-16

Underwater Wireless Sensor Network (UWSN) communication at high frequencies is extremely challenging. The intricacies presented by the underwater environment are far more compared to the terrestrial environment. The prime reason for such intricacies are the physical characteristics of the underwater environment that have a big impact on electromagnetic (EM) signals. Acoustics signals are by far the most preferred choice for underwater wireless communication. Because high frequency signals have the luxury of large bandwidth (BW) at shorter distances, high frequency EM signals cannot penetrate and propagate deep in underwater environments. The EM properties of water tend to resist their propagation and cause severe attenuation. Accordingly, there are two questions that need to be addressed for underwater environment, first what happens when high frequency EM signals operating at 2.4 GHz are used for communication, and second which factors affect the most to high frequency EM signals. To answer these questions, we present real-time experiments conducted at 2.4 GHz in terrestrial and underwater (fresh water) environments. The obtained results helped in studying the physical characteristics (i.e., EM properties, propagation and absorption loss) of underwater environments. It is observed that high frequency EM signals can propagate in fresh water at a shallow depth only and can be considered for a specific class of applications such as water sports. Furthermore, path loss, velocity of propagation, absorption loss and the rate of signal loss in different underwater environments are also calculated and presented in order to understand why EM signals cannot propagate in sea water and oceanic water environments. An optimal solk6ution for underwater communication in terms of coverage distance, bandwidth and nature of communication is presented, along with possible underwater applications of UWSNs at 2.4 GHz.

Submerged AUV Charging Station

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Chao, Yi; Curtin, Thomas

2014-01-01

Autonomous Underwater Vehicles (AUVs) are becoming increasingly important for military surveillance and mine detection. Most AUVs are battery powered and have limited lifetimes of a few days to a few weeks. This greatly limits the distance that AUVs can travel underwater. Using a series of submerged AUV charging stations, AUVs could travel a limited distance to the next charging station, recharge its batteries, and continue to the next charging station, thus traveling great distances in a relatively short time, similar to the Old West “Pony Express.” One solution is to use temperature differences at various depths in the ocean to produce electricity, which is then stored in a submerged battery. It is preferred to have the upper buoy submerged a reasonable distance below the surface, so as not to be seen from above and not to be inadvertently destroyed by storms or ocean going vessels. In a previous invention, a phase change material (PCM) is melted (expanded) at warm temperatures, for example, 15 °C, and frozen (contracted) at cooler temperatures, for example, 8 °C. Tubes containing the PCM, which could be paraffin such as pentadecane, would be inserted into a container filled with hydraulic oil. When the PCM is melted (expanded), it pushes the oil out into a container that is pressurized to about 3,000 psi (approx equals 20.7 MPa). When a valve is opened, the high-pressure oil passes through a hydraulic motor, which turns a generator and charges a battery. The low-pressure oil is finally reabsorbed into the PCM canister when the PCM tubes are frozen (contracted). Some of the electricity produced could be used to control an external bladder or a motor to the tether line, such that depth cycling is continued for a very long period of time. Alternatively, after the electricity is generated by the hydraulic motor, the exiting low-pressure oil from the hydraulic motor could be vented directly to an external bladder on the AUV, such that filling of the bladder causes the AUV to rise, and emptying of the bladder allows the AUV to descend. This type of direct buoyancy control is much more energy efficient than using electrical pumps in that the inefficiencies of converting thermal energy to electrical energy to mechanical energy is avoided. AUV charging stations have been developed that use electricity produced by waves on floating buoys and that use electricity from solar photovoltaics on floating buoys. This is the first device that has absolutely no floating or visible parts, and is thus impervious to storms, inadvertent ocean vessel collisions, or enemy sabotage.

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

NASA Astrophysics Data System (ADS)

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.

Electrochromic device using mercaptans and organothiolate compounds

DOEpatents

Lampert, Carl M.; Ma, Yan-ping; Doeff, Marca M.; Visco, Steven

1995-01-01

An electrochromic cell is disclosed which comprises an electrochromic layer and a composite ion counter electrode for transporting ions. The counter electrode further comprises a polymer electrolyte material and an organosulfur material in which, in its discharged state, the organosulfur material is further comprised of a mercaptan or an organothiolate. In one preferred embodiment, both the electrochromic electrode and the counter electrode are transparent either to visible light or to the entire electromagnetic spectrum in both charged and discharged states. An electrochromic device is disclosed which comprises one or more electrochromic electrodes encased in glass or plastic plates on the inner surface of each of which is formed a transparent electrically conductive film. Electrical contacts, which are in electrical contact with the conductive films, facilitate external electrical connection.

Influence of electrical resistivity and machining parameters on electrical discharge machining performance of engineering ceramics.

PubMed

Ji, Renjie; Liu, Yonghong; Diao, Ruiqiang; Xu, Chenchen; Li, Xiaopeng; Cai, Baoping; Zhang, Yanzhen

2014-01-01

Engineering ceramics have been widely used in modern industry for their excellent physical and mechanical properties, and they are difficult to machine owing to their high hardness and brittleness. Electrical discharge machining (EDM) is the appropriate process for machining engineering ceramics provided they are electrically conducting. However, the electrical resistivity of the popular engineering ceramics is higher, and there has been no research on the relationship between the EDM parameters and the electrical resistivity of the engineering ceramics. This paper investigates the effects of the electrical resistivity and EDM parameters such as tool polarity, pulse interval, and electrode material, on the ZnO/Al2O3 ceramic's EDM performance, in terms of the material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR). The results show that the electrical resistivity and the EDM parameters have the great influence on the EDM performance. The ZnO/Al2O3 ceramic with the electrical resistivity up to 3410 Ω·cm can be effectively machined by EDM with the copper electrode, the negative tool polarity, and the shorter pulse interval. Under most machining conditions, the MRR increases, and the SR decreases with the decrease of electrical resistivity. Moreover, the tool polarity, and pulse interval affect the EWR, respectively, and the electrical resistivity and electrode material have a combined effect on the EWR. Furthermore, the EDM performance of ZnO/Al2O3 ceramic with the electrical resistivity higher than 687 Ω·cm is obviously different from that with the electrical resistivity lower than 687 Ω·cm, when the electrode material changes. The microstructure character analysis of the machined ZnO/Al2O3 ceramic surface shows that the ZnO/Al2O3 ceramic is removed by melting, evaporation and thermal spalling, and the material from the working fluid and the graphite electrode can transfer to the workpiece surface during electrical discharge machining ZnO/Al2O3 ceramic.

Survey and Recording Technologies in Italian Underwater Cultural Heritage: Research and Public Access Within the Framework of the 2001 UNESCO Convention

NASA Astrophysics Data System (ADS)

Secci, Massimiliano

2017-08-01

The 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage is slowly but peremptorily becoming a standard reference tool for underwater archaeology and underwater cultural heritage management. The many provisions included within the Convention touch on many aspects that are key to an effective protection and promotion of the underwater cultural heritage. Within the web of these provisions many aspects are gaining consideration and driving research in underwater archaeology worldwide. These provisions, when seen within a wider frame of social, economical and technological dynamics, pinpoint many aspects requiring further scrutiny from the disciplinary circle. In the framework of the 2001 UNESCO Convention, this article will analyze the path traveled in technological acquisition in the practice of Italian underwater archaeology and how this has affected the approach to underwater cultural heritage management, particularly highlighting how this process has been further influenced by the adoption in 2001 of the Convention and Italy's ratification of it in 2010.

Single underwater image enhancement based on color cast removal and visibility restoration

NASA Astrophysics Data System (ADS)

Li, Chongyi; Guo, Jichang; Wang, Bo; Cong, Runmin; Zhang, Yan; Wang, Jian

2016-05-01

Images taken under underwater condition usually have color cast and serious loss of contrast and visibility. Degraded underwater images are inconvenient for observation and analysis. In order to address these problems, an underwater image-enhancement method is proposed. A simple yet effective underwater image color cast removal algorithm is first presented based on the optimization theory. Then, based on the minimum information loss principle and inherent relationship of medium transmission maps of three color channels in an underwater image, an effective visibility restoration algorithm is proposed to recover visibility, contrast, and natural appearance of degraded underwater images. To evaluate the performance of the proposed method, qualitative comparison, quantitative comparison, and color accuracy test are conducted. Experimental results demonstrate that the proposed method can effectively remove color cast, improve contrast and visibility, and recover natural appearance of degraded underwater images. Additionally, the proposed method is comparable to and even better than several state-of-the-art methods.

Effect of toughened epoxy resin on partial discharge at solid-solid interface

NASA Astrophysics Data System (ADS)

Li, Manping; Wu, Kai; Zhang, Zhao; Cheng, Yonghong

2017-02-01

A series of solid-solid interfaces, consisting of ceramic-epoxy resin interface samples with a tip-plate electrode, were investigated by performing partial discharge tests and real-time electrical tree observations. A toughening agent was added to the epoxy resin at different ratios for comparison. The impact strength, differential scanning calorimetry (DSC) and dielectric properties of the cured compositions and ceramic were tested. The electric field strength at the tip was calculated based on Maxwell’s theory. The test results show that the addition of a toughener can improve the impact strength of epoxy resin but it decreases the partial discharge inception voltage (PDIV) of the interface sample. At the same time, toughening leads to complex branches of the electrical tree. The simulation result suggests that this reduction of the PDIV cannot be explained by a change of permittivity due to the addition of a toughening agent. The microstructural change caused by toughening was considered to be the key factor for lower PDIV and complex electrical tree branches. Supported by China Academy of Engineering Physics (Project 2014B05005).

Simulation study on transient electric shock characteristics of human body under high voltage ac transmission lines

NASA Astrophysics Data System (ADS)

Huang, Tao; Zou, Yanhui; Lv, Jianhong; Yang, Jinchun; Tao, Li; Zhou, Jianfei

2017-09-01

Human body under high-voltage AC transmission lines will produce a certain induced voltage due to the electrostatic induction. When the human body contacts with some grounded objects, the charges transfer from the body to the ground and produce contact current which may cause transient electric shock. Using CDEGS and ATP/EMTP, the paper proposes a method for quantitatively calculating the transient electric shock characteristics. It calculates the human body voltage, discharge current and discharge energy under certain 500kV compact-type transmission lines and predicts the corresponding human feelings. The results show that the average root value of discharge current is less than 10mA when the human body is under the 500kV compact-type transmission lines and the human body is overall safe if the transmission lines satisfy the relevant design specifications. It concludes that the electric field strength above the ground should be limited to 4kV/m through the residential area for the purpose of reducing the electromagnetic impact.

Development of an Eco-Friendly Electrical Discharge Machine (E-EDM) Using TRIZ Approach

NASA Astrophysics Data System (ADS)

Sreebalaji, V. S.; Saravanan, R.

Electrical Discharge Machine (EDM) is one of the non-traditional machining processes. EDM process is based on thermoelectric energy between the work and an electrode. A pulse discharge occurs in a small gap between the work piece and the electrode and removes the unwanted material from the parent metal through melting and vaporization. The electrode and the work piece must have an electrical conductivity in order to generate the spark. Dielectric fluid acts as a spark conductor, concentrating the energy to a very narrow region. There are various types of products can be produced and finished using EDM such as Moulds, Dies, Parts of Aerodynamics, Automotives and Surgical components. This research work reveals how an Eco friendly EDM (E-EDM) can be modeled to replace die electric fluid and introducing ozonised oxygen in to EDM to eliminate harmful effects generated while machining by using dielectric, to make pollution free machining environment through a new design of EEDM using TRIZ (a Russian acronym for Theory of Inventive Problem Solving) approach, since Eco friendly design is the need of the hour.

Determination of the electric field strength of filamentary DBDs by CARS-based four-wave mixing

NASA Astrophysics Data System (ADS)

Böhm, P.; Kettlitz, M.; Brandenburg, R.; Höft, H.; Czarnetzki, U.

2016-10-01

It is demonstrated that a four-wave mixing technique based on coherent anti-Stokes Raman spectroscopy (CARS) can determine the electric field strength of a pulsed-driven filamentary dielectric barrier discharge (DBD) of 1 mm gap, using hydrogen as a tracer medium in nitrogen at atmospheric pressure. The measurements are presented for a hydrogen admixture of 10%, but even 5% H2 admixture delivers sufficient infrared signals. The lasers do not affect the discharge by photoionization or by other radiation-induced processes. The absolute values of the electric field strength can be determined by the calibration of the CARS setup with high voltage amplitudes below the ignition threshold of the arrangement. This procedure also enables the determination of the applied breakdown voltage. The alteration of the electric field is observed during the internal polarity reversal and the breakdown process. One advantage of the CARS technique over emission-based methods is that it can be used independently of emission, e.g. in the pre-phase and in between two consecutive discharges, where no emission occurs at all.

The effect of the electric wind on the spatial distribution of chemical species in the positive corona discharge

NASA Astrophysics Data System (ADS)

Yanallah, K.; Pontiga, F.; Bouazza, M. R.; Chen, J. H.

2017-08-01

The electrohydrodynamic air flow generated by a positive corona discharge, and its effect on the spatial distribution of chemical species within a wire-plate corona reactor, have been numerically simulated. The computational model is based on the solutions of the Navier-Stokes equation and the continuity equation of each chemical species generated by the electrical discharge. A simplified analytical expression of the electric force density, which only requires the current density as the input parameter, has been used in the Navier-Stokes equation to obtain the velocity field. For the solution of the continuity equations, a plasma chemistry model that includes the most important reactions between electrons, atoms and molecules in air has been used. Similar to the electric force, the electron density distribution has been approximated by using a semi-analytical expression appropriate for the electrode geometry. The results of the study show that the spatial distribution of chemical species can be very different, and depends on the interplay between the electrohydrodynamic flow, the chemical kinetics of the species and its characteristic lifetime.

An Underwater Target Detection System for Electro-Optical Imagery Data

DTIC Science & Technology

2010-06-01

detection and segmentation of underwater mine-like objects in the EO images captured with a CCD-based image sensor. The main focus of this research is to...develop a robust detection algorithm that can be used to detect low contrast and partial underwater objects from the EO imagery with low false alarm rate...underwater target detection I. INTRODUCTION Automatic detection and recognition of underwater objects from EO imagery poses a serious challenge due to poor

Interactions between surface discharges induced by volume discharges in a dielectric barrier discharge system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Yenan; Dong, Lifang, E-mail: donglfhbu@163.com; Zhao, Longhu

2014-10-15

The interaction between micro-discharges involved in surface discharges (SDs) is studied in dielectric barrier discharge system. Instantaneous images taken by high speed cameras show that the SDs are induced by volume discharges (VDs). They cannot cross the midperpendicular of two neighbouring volume charges at low voltage while they stretch along it at high voltage, indicating that there is interaction between SDs. The differences of plasma parameters between SD and VD are studied by optical emission spectroscopy. The simulation of the electric fields of the wall charges accumulated by VD further confirms the existence of the interaction.

Stackelberg Game Model of Wind Farm and Electric Vehicle Battery Switch Station

NASA Astrophysics Data System (ADS)

Jiang, Zhe; Li, Zhimin; Li, Wenbo; Wang, Mingqiang; Wang, Mengxia

2017-05-01

In this paper, a cooperation method between wind farm and Electric vehicle battery switch station (EVBSS) was proposed. In the pursuit of maximizing their own benefits, the cooperation between wind farm and EVBSS was formulated as a Stackelberg game model by treating them as decision makers in different status. As the leader, wind farm will determine the charging/discharging price to induce the charging and discharging behavior of EVBSS reasonably. Through peak load shifting, wind farm could increase its profits by selling more wind power to the power grid during time interval with a higher purchase price. As the follower, EVBSS will charge or discharge according to the price determined by wind farm. Through optimizing the charging /discharging strategy, EVBSS will try to charge with a lower price and discharge with a higher price in order to increase its profits. Since the possible charging /discharging strategy of EVBSS is known, the wind farm will take the strategy into consideration while deciding the charging /discharging price, and will adjust the price accordingly to increase its profits. The case study proved that the proposed cooperation method and model were feasible and effective.

Toward a Time-Domain Fractal Lightning Simulation

NASA Astrophysics Data System (ADS)

Liang, C.; Carlson, B. E.; Lehtinen, N. G.; Cohen, M.; Lauben, D.; Inan, U. S.

2010-12-01

Electromagnetic simulations of lightning are useful for prediction of lightning properties and exploration of the underlying physical behavior. Fractal lightning models predict the spatial structure of the discharge, but thus far do not provide much information about discharge behavior in time and therefore cannot predict electromagnetic wave emissions or current characteristics. Here we develop a time-domain fractal lightning simulation from Maxwell's equations, the method of moments with the thin wire approximation, an adaptive time-stepping scheme, and a simplified electrical model of the lightning channel. The model predicts current pulse structure and electromagnetic wave emissions and can be used to simulate the entire duration of a lightning discharge. The model can be used to explore the electrical characteristics of the lightning channel, the temporal development of the discharge, and the effects of these characteristics on observable electromagnetic wave emissions.

Theoretical investigation of discharge parameters in magnetized radio frequency excited CO2 lasers

NASA Astrophysics Data System (ADS)

Tavassoli, H.; Sohbatzadeh, F.; Latifi, H.

2003-06-01

In the present paper the magnetic field effects on discharge parameters in rf excited CO2 lasers are calculated. A rf generated plasma imbedded in an external, constant, and homogeneous magnetic field is considered. The continuity equation is used to derive the electron density. Quasineutrality condition and ambipolar diffusion are used. Electron attachment coefficient is neglected. Local electric field, local electron density, and thickness of charge layers are derived as a function of distance from the electrodes and magnetic field. The thickness of charge layers in the presence of magnetic field is always smaller than one without the magnetic field. When the magnetic field increases, the electron density increases in all regions of discharge, and the electric field reduces in the charge layers but increases in the middle part of discharge.

Determination of the levitation limits of dust particles within the sheath in complex plasma experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Douglass, Angela; Land, Victor; Qiao Ke

2012-01-15

Experiments are performed in which dust particles are levitated at varying heights above the powered electrode in a radio frequency plasma discharge by changing the discharge power. The trajectories of particles dropped from the top of the discharge chamber are used to reconstruct the vertical electric force acting on the particles. The resulting data, together with the results from a self-consistent fluid model, are used to determine the lower levitation limit for dust particles in the discharge and the approximate height above the lower electrode where quasineutrality is attained, locating the sheath edge. These results are then compared with currentmore » sheath models. It is also shown that particles levitated within a few electron Debye lengths of the sheath edge are located outside the linearly increasing portion of the electric field.« less

Removal of a hydrogenated amorphous carbon film from the tip of a micropipette electrode using direct current corona discharge.

PubMed

Kakuta, Naoto; Okuyama, Naoki; Yamada, Yukio

2010-02-01

Micropipette electrodes are fabricated by coating glass micropipettes first with metal and then with hydrogenated amorphous carbon (a-C:H) as an electrical insulator. Furthermore, at the tip of the micropipette electrode, the deposited a-C:H film needs to be removed to expose the metal-coated surface and hollow for the purposes of electrical measurement and injection. This paper describes a convenient and reliable method for removing the a-C:H film using direct current corona discharge in atmospheric air. The initial film removal occurred at an applied voltage of 1.5-2.0 kV, accompanied by an abrupt increase in the discharge current. The discharge current then became stable at a microampere level in the glow corona mode, and the removed area gradually extended.

Focal Length Controllable Ultrasonic Transducer Using Bimorph-Type Bending Actuator

NASA Astrophysics Data System (ADS)

Chae, Min-Ku; Kim, Moo-Joon; Ha, Kang-Lyeol; Lee, Chai-Bong

2003-05-01

Using a bimorph-type bending actuator, we propose a new method for controlling the focal length of a transducer by electric DC voltage. We designed two focal length controllable ultrasonic transducers with actuators, a line-focus and a point-focus transducer. The polyvinylidene fluoride (PVDF) piezoelectric type polymer film is used for transmitting and receiving of ultrasonic signals. Using the new method, it is confirmed by investigation of the underwater acoustic field that the focal length can be controlled to within 10% of the radius of the transducer curvature.

The Development of a High-Power, Low-Frequency Underwater Acoustic Source for Use in a Deep-Towed Geophysical Array Section

DTIC Science & Technology

1982-11-15

Metca) for each ring 6 Aluminum orirlce end ring 15 Rubber bumpers 7 Back plate inner boot ring 16 Castor oil rill-fluid I ’)-ring %eals I ’ Nikel ...electrode .ab% with hook-up wire -ig. 6 - Sectional v-icw orf ISRI) typc (662 tran.dhcer 9 YOUNG, TIMS. AND HENRIQUFZ 0.42 m. Approximately 85% of the...electrical leads for each ring are routed to individual bulkhead connectors on the trans- ducer back plate with high-voltage silicone-jacketed hookup wire

Characterization of a dielectric barrier discharge in contact with liquid and producing a plasma activated water

NASA Astrophysics Data System (ADS)

Neretti, G.; Taglioli, M.; Colonna, G.; Borghi, C. A.

2017-01-01

In this work a low-temperature plasma source for the generation of plasma activated water (PAW) is developed and characterized. The plasma reactor was operated by means of an atmospheric-pressure air dielectric barrier discharge (DBD). The plasma generated is in contact with the water surface and is able to chemically activate the liquid medium. Electrodes were supplied by both sinusoidal and nanosecond-pulsed voltage waveforms. Treatment times were varied from 2 to 12 min to increase the energy dose released to the water by the DBD plasma. The physics of the discharge was studied by means of electrical, spectroscopic and imaging diagnostics. The interaction between the plasma and the liquid was investigated as well. Temperature and composition of the treated water were detected. Images of the discharges showed a filamentary behaviour in the sinusoidal case and a more homogeneous behaviour in the nanosecond-pulsed one. The images and the electrical measurements allowed to evaluate an average electron number density of about 4  ×  1019 and 6  ×  1017 m-3 for the sinusoidal and nanosecond-pulsed discharges respectively. Electron temperatures in the range of 2.1÷2.6 eV were measured by using spectroscopic diagnostics. Rotational temperatures in the range of 318-475 K were estimated by fitting synthetic spectra with the measured ones. Water temperature and pH level did not change significantly after the exposure to the DBD plasma. The production of ozone and hydrogen peroxide within the water was enhanced by increasing the plasma treatment time and the energy dose. Numerical simulations of the nanosecond-pulsed discharge were performed by using a self-consistent coupling of state-to-state kinetics of the air mixture with the Boltzmann equation of free electron kinetics. Temporal evolution of the electron energy distribution function shows departure from the Maxwellian distribution especially during the afterglow phase of the discharge. When limited deviations from Maxwellian distribution were observed, calculated electron temperature is in good agreement with the one measured by means of spectroscopic diagnostics. Computed temporal evolution of the energy delivered to the discharge is comparable with the one obtained from electrical measurements. The electrical discharges supplied by both voltage waveforms produce plasma activated water with negligible thermal effects and pH variations.

46 CFR 167.15-33 - Underwater Survey in Lieu of Drydocking (UWILD).

Code of Federal Regulations, 2010 CFR

2010-10-01

... SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Inspections § 167.15-33 Underwater Survey in Lieu of Drydocking (UWILD). (a) The Officer in Charge, Marine Inspection (OCMI), may approve an underwater survey instead of..., Marine Inspection submits a recommendation for future underwater surveys, the results of the hull gauging...

Resources for Underwater Robotics Education

ERIC Educational Resources Information Center

Wallace, Michael L.; Freitas, William M.

2016-01-01

4-H clubs can build and program underwater robots from raw materials. An annotated resource list for engaging youth in building underwater remotely operated vehicles (ROVs) is provided. This article is a companion piece to the Research in Brief article "Building Teen Futures with Underwater Robotics" in this issue of the "Journal of…

A prototype of an electric-discharge gas flow oxygen-iodine laser: I. Modeling of the processes of singlet oxygen generation in a transverse cryogenic slab RF discharge

NASA Astrophysics Data System (ADS)

Vagin, N. P.; Ionin, A. A.; Kochetov, I. V.; Napartovich, A. P.; Sinitsyn, D. V.; Yuryshev, N. N.

2017-03-01

The existing kinetic model describing self-sustained and electroionization discharges in mixtures enriched with singlet oxygen has been modified to calculate the characteristics of a flow RF discharge in molecular oxygen and its mixtures with helium. The simulations were performed in the gas plug-flow approximation, i.e., the evolution of the plasma components during their motion along the channel was represented as their evolution in time. The calculations were carried out for the O2: He = 1: 0, 1: 1, 1: 2, and 1: 3 mixtures at an oxygen partial pressure of 7.5 Torr. It is shown that, under these conditions, volumetric gas heating in a discharge in pure molecular oxygen prevails over gas cooling via heat conduction even at an electrode temperature as low as 100 K. When molecular oxygen is diluted with helium, the behavior of the gas temperature changes substantially: heat removal begins to prevail over volumetric gas heating, and the gas temperature at the outlet of the discharge zone drops to 220-230 K at room gas temperature at the inlet, which is very important in the context of achieving the generation threshold in an electric-discharge oxygen-iodine laser based on a slab cryogenic RF discharge.

Dual-frequency glow discharges in atmospheric helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Xiaojiang; Guo, Ying; Magnetic Confinement Fusion Research Center, Ministry of Education of the People's Republic of China, Shanghai 201620

2015-10-15

In this paper, the dual-frequency (DF) glow discharges in atmospheric helium were experimented by electrical and optical measurements in terms of current voltage characteristics and optical emission intensity. It is shown that the waveforms of applied voltages or discharge currents are the results of low frequency (LF) waveforms added to high frequency (HF) waveforms. The HF mainly influences discharge currents, and the LF mainly influences applied voltages. The gas temperatures of DF discharges are mainly affected by HF power rather than LF power.

Modeling of glow discharge in a gas flow

NASA Astrophysics Data System (ADS)

Galeev, I. G.; Asadullin, T. Ya

2017-11-01

The discharge plasma of positive column in electronegative gas flow has been described by two-dimensional integro-differential system of equations written in the approximation of “narrow channel”. An efficient algorithm of solving this system of equations is suggested. In this work an implicit method is used of solution with selection gradient of the electric field along the channel. The simulation of discharge characteristics was conducted under various boundary conditions at the inlet of the discharge area and with various full discharge currents.

Study of the homogeneity of the current distribution in a dielectric barrier discharge in air by means of a segmented electrode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malashin, M. V., E-mail: m-malashin@mail.ru; Moshkunov, S. I.; Khomich, V. Yu.

2016-02-15

The current distribution in a dielectric barrier discharge in atmospheric-pressure air at a natural humidity of 40–60% was studied experimentally with a time resolution of 200 ps. The experimental results are interpreted by means of numerically simulating the discharge electric circuit. The obtained results indicate that the discharge operating in the volumetric mode develops simultaneously over the entire transverse cross section of the discharge gap.

APPARATUS FOR PRODUCING AND MANIPULATING PLASMAS

DOEpatents

Colgate, S.A.; Ferguson, J.P.; Furth, H.P.; Wright, R.E.

1960-07-26

An electrical pinch discharge apparatus is described for producing and manipulating high-temperature plasmas. The apparatus may be of either the linear or toroidal pinch discharge type. Arrangements are provided whereby stabilizing fields may be trapped in the plasma external to the main pinch discharge path and the boundary condition of the stabilizing field programed so as to stabilize the discharge or to promote instabilities in the discharge as desired. The produced plasmas may be employed for various purposes, and fusion neutrons have been produced with the apparatus.

Localized heating of electrons in ionization zones: Going beyond the Penning-Thornton paradigm in magnetron sputtering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anders, Andre

2014-12-07

The fundamental question of how energy is supplied to a magnetron discharge is commonly answered by the Penning-Thornton paradigm invoking secondary electrons. Huo et al. (Plasma Sources Sci. Technol. 22, 045005, (2013)) used a global discharge model to show that electron heating in the electric field of the magnetic presheath is dominant. In this contribution, this concept is applied locally taking into account the electric potential structure of ionization zones. Images of ionization zones can and should be interpreted as diagrams of the localization of electric potential and related electron energy, where certain collisions promote or dampen their formation.

Ignition and Flameholding in a Supersonic Combustor by an Electrical Discharge Combined with a Fuel Injector

DTIC Science & Technology

2014-01-01

W.F. O’Brien, J.A. Schetz - Plasma torch atomizer-igniter for supersonic combustion of liquid hydrocarbon fuels // AIAA Paper 2006-7970. 6. H. Do...A. Deminsky, I. V. Kochetov, A. P. Napartovich, S. B. Leonov, - “Modeling of Plasma Assisted Combustion in Premixed Supersonic Gas Flow...1 Ignition and Flameholding in a Supersonic Combustor by an Electrical Discharge Combined with a Fuel Injector K. V. Savelkin 1 , D. A

Ignitability of Diesel Fuel with an Inclusion of Ultrafine Carbon Particles

NASA Astrophysics Data System (ADS)

Krivosheev, P. N.; Leshchevich, V. V.; Shimchenko, S. Yu.; Shushkov, S. V.; Penyazkov, O. G.

2017-11-01

Nanosize carbon fuel additions were synthesized by the action of an electric discharge on a diesel fuel. Depending on the discharge regime, variously shaped carbon particles, including planar graphitized ones, were formed in the fuel. Ignitability of the produced samples was assessed by the method of initiation of a foamed fuel sample by a lowcurrent electric arc. The modified fuel showed the improvement of the ignition characteristics in the presence of a nanodispersed solid phase.

Negative DC corona discharge current characteristics in a flowing two-phase (air + suspended smoke particles) fluid

NASA Astrophysics Data System (ADS)

Berendt, Artur; Domaszka, Magdalena; Mizeraczyk, Jerzy

2017-04-01

The electrical characteristics of a steady-state negative DC corona discharge in a two-phase fluid (air with suspended cigarette smoke particles) flowing along a chamber with a needle-to-plate electrode arrangement were experimentally investigated. The two-phase flow was transverse in respect to the needle-to-plate axis. The velocity of the transverse two-phase flow was limited to 0.8 m/s, typical of the electrostatic precipitators. We found that three discharge current modes of the negative corona exist in the two-phase (air + smoke particles) fluid: the Trichel pulses mode, the "Trichel pulses superimposed on DC component" mode and the DC component mode, similarly as in the corona discharge in air (a single-phase fluid). The shape of Trichel pulses in the air + suspended particles fluid is similar to that in air. However, the Trichel pulse amplitudes are higher than those in "pure" air while their repetition frequency is lower. As a net consequence of that the averaged corona discharge current in the two-phase fluid is lower than in "pure" air. It was also found that the average discharge current decreases with increasing suspended particle concentration. The calculations showed that the dependence of the average negative corona current (which is a macroscopic corona discharge parameter) on the particle concentration can be explained by the particle-concentration dependencies of the electric charge of Trichel pulse and the repetition frequency of Trichel pulses, both giving a microscopic insight into the electrical phenomena in the negative corona discharge. Our investigations showed also that the average corona discharge current in the two-phase fluid is almost unaffected by the transverse fluid flow up to a velocity of 0.8 m/s. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

Development of V2G and G2V Power Profiles and Their Implications on Grid Under Varying Equilibrium of Aggregated Electric Vehicles

NASA Astrophysics Data System (ADS)

Jain, Prateek; Jain, Trapti

2016-04-01

The objective of this paper is to examine the vehicle-to-grid (V2G) power capability of aggregated electric vehicles (EV) in the manner that they are being adopted by the consumers with their growing infiltration in the vehicles market. The proposed modeling of V2G and grid-to-vehicle (G2V) energy profiles blends the heterogeneous attributes namely, driven mileages, arrival and departure times, travel and parking durations, and speed dependent energy consumption of mobility trends. Three penetration percentages of 25 %, 50 % and 100 % resulting in varied compositions of battery electric vehicle (BEV) and plug-in hybrid electric vehicle (PHEV) in the system, as determined by the consumers' acceptance, have been considered to evaluate the grid capacity for V2G. Distinct charge-discharge powers have been selected as per charging standards to match contemporary vehicles and infrastructure requirements. Charging and discharging approaches have been devised to replicate non-linear characteristics of Li-ion battery. Effects of simultaneous conjunction of V2G and G2V power curves with daily conventional load profile are quantified drawn upon workplace-discharging home-charging scheme. Results demonstrated a marked drop in load and hence in market price during morning hours which is hurriedly overcompensated by the hike during evening hours with rising penetration level and charge-discharge power.

Channel analysis for single photon underwater free space quantum key distribution.

PubMed

Shi, Peng; Zhao, Shi-Cheng; Gu, Yong-Jian; Li, Wen-Dong

2015-03-01

We investigate the optical absorption and scattering properties of underwater media pertinent to our underwater free space quantum key distribution (QKD) channel model. With the vector radiative transfer theory and Monte Carlo method, we obtain the attenuation of photons, the fidelity of the scattered photons, the quantum bit error rate, and the sifted key generation rate of underwater quantum communication. It can be observed from our simulations that the most secure single photon underwater free space QKD is feasible in the clearest ocean water.

[Effect of electromagnetic radiation on discharge activity of neurons in the hippocampus CA1 in rats].

PubMed

Tong, Jun; Chen, Su; Liu, Xiang-Ming; Hao, Dong-Mei

2013-09-01

In order to explore effect of electromagnetic radiation on learning and memory ability of hippocampus neuron in rats, the changes in discharge patterns and overall electrical activity of hippocampus neuron after electromagnetic radiation were observed. Rat neurons discharge was recorded with glass electrode extracellular recording technology and a polygraph respectively. Radiation frequency of electromagnetic wave was 900 MHZ and the power was 10 W/m2. In glass electrode extracellular recording, the rats were separately irradiated for 10, 20, 30, 40, 50 and 60 min, every points repeated 10 times and updated interval of 1h, observing the changes in neuron discharge and spontaneous discharge patterns after electromagnetic radiation. In polygraph recording experiments, irradiation group rats for five days a week, 6 hours per day, repeatedly for 10 weeks, memory electrical changes in control group and irradiation group rats when they were feeding were repeatedly monitored by the implanted electrodes, observing the changes in peak electric digits and the largest amplitude in hippocampal CA1 area, and taking some electromagnetic radiation sampling sequence for correlation analysis. (1) Electromagnetic radiation had an inhibitory role on discharge frequency of the hippocampus CA1 region neurons. After electromagnetic radiation, discharge frequency of the hippocampus CA1 region neurons was reduced, but the changes in scale was not obvious. (2) Electromagnetic radiation might change the spontaneous discharge patterns of hippocampus CA1 region neurons, which made the explosive discharge pattern increased obviously. (3) Peak potential total number within 5 min in irradiation group was significantly reduced, the largest amplitude was less than that of control group. (4) Using mathematical method to make the correlation analysis of the electromagnetic radiation sampling sequence, that of irradiation group was less than that of control group, indicating that there was a tending to be inhibitory connection between neurons in irradiation group after electromagnetic radiation. Electromagnetic radiation may cause structure and function changes of transfer synaptic in global, make hippocampal CA1 area neurons change in the overall discharge characteristic and discharge patterns, thus lead to decrease in the ability of learning and memory.

Primary lithium organic electrolyte battery BA-5588

NASA Astrophysics Data System (ADS)

Rosansky, M. G.

1982-07-01

This program concerns the development, fabrication and evaluation of a Lithium organic electrolyte battery designated BA-5588 ()/U which incorporates five series connected, hermetically sealed cells housed in a plastic case. Significant effort was directed towards cell optimization through controlled experimentation and evaluation of various design parameters. Demonstration of the effectiveness of the finalized design was accomplished by the performance of various electrical and abuse tests which included environmental exposure, prolonged thermal storage, electrical discharge under various thermal profiles, short circuit and discharge to zero volts as well as forced discharge. The resulting evaluation demonstrated the batteries ability to operate safely under all of the specified abusive environments and provide 100% of the specified service life requirements.

Transport Equations Resolution By N-BEE Anti-Dissipative Scheme In 2D Model Of Low Pressure Glow Discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kraloua, B.; Hennad, A.

The aim of this paper is to determine electric and physical properties by 2D modelling of glow discharge low pressure in continuous regime maintained by term constant source. This electric discharge is confined in reactor plan-parallel geometry. This reactor is filled by Argon monatomic gas. Our continuum model the order two is composed the first three moments the Boltzmann's equations coupled with Poisson's equation by self consistent method. These transport equations are discretized by the finite volumes method. The equations system is resolved by a new technique, it is about the N-BEE explicit scheme using the time splitting method.

Discharge pulse phenomenology

NASA Technical Reports Server (NTRS)

Frederickson, A. R.

1985-01-01

A model was developed which places radiation induced discharge pulse results into a unified conceptual framework. Only two phenomena are required to interpret all space and laboratory results: (1) radiation produces large electrostatic fields inside insulators via the trapping of a net space charge density; and (2) the electrostatic fields initiate discharge streamer plasmas similar to those investigated in high voltage electrical insulation materials; these streamer plasmas generate the pulsing phenomena. The apparent variability and diversity of results seen is an inherent feature of the plasma streamer mechanism acting in the electric fields which is created by irradiation of the dielectrics. The implications of the model are extensive and lead to constraints over what can be done about spacecraft pulsing.

Influence of driving frequency on discharge modes in a dielectric-barrier discharge with multiple current pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Weiman; Tang, Jie; Wang, Yishan

2013-07-15

A one-dimensional self-consistent fluid model was employed to investigate the effect of the driving frequency on the discharge modes in atmospheric-pressure argon discharge with multiple current pulses. The discharge mode was discussed in detail not only at current peaks but also between two adjacent peaks. The simulation results show that different transitions between the Townsend and glow modes during the discharge take place with the driving frequency increased. A complicated transition from the Townsend mode, through glow, Townsend, and glow, and finally back to the Townsend one is found in the discharge with the driving frequency of 8 kHz. Theremore » is a tendency of transition from the Townsend to glow mode for the discharge both at the current peaks and troughs with the increasing frequency. The discharge in the half period can all along operate in the glow mode with the driving frequency high enough. This is resulted from the preservation of more electrons in the gas gap and acquisition of more electron energy from the swiftly varying electric field with the increase in driving frequency. Comparison of the spatial and temporal evolutions of the electron density at different driving frequencies indicates that the increment of the driving frequency allows the plasma chemistry to be enhanced. This electrical characteristic is important for the applications, such as surface treatment and biomedical sterilization.« less

Optimized decoy state QKD for underwater free space communication

NASA Astrophysics Data System (ADS)

Lopes, Minal; Sarwade, Nisha

Quantum cryptography (QC) is envisioned as a solution for global key distribution through fiber optic, free space and underwater optical communication due to its unconditional security. In view of this, this paper investigates underwater free space quantum key distribution (QKD) model for enhanced transmission distance, secret key rates and security. It is reported that secure underwater free space QKD is feasible in the clearest ocean water with the sifted key rates up to 207kbps. This paper extends this work by testing performance of optimized decoy state QKD protocol with underwater free space communication model. The attenuation of photons, quantum bit error rate and the sifted key generation rate of underwater quantum communication is obtained with vector radiative transfer theory and Monte Carlo method. It is observed from the simulations that optimized decoy state QKD evidently enhances the underwater secret key transmission distance as well as secret key rates.

Improved plasma accelerator

NASA Technical Reports Server (NTRS)

Cheng, D. Y.

1971-01-01

Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

46 CFR 105.20-10 - Pumps.

Code of Federal Regulations, 2010 CFR

2010-10-01

... discharge side of pump if the pressure under shutoff conditions exceeds 60 pounds. When a relief valve is installed, it shall discharge back to the suction of the pump. (c) Where electric motors are installed with...

46 CFR 169.229 - Drydock examination, internal structural examination, and underwater survey intervals.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., and underwater survey intervals. 169.229 Section 169.229 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... Hauling Out § 169.229 Drydock examination, internal structural examination, and underwater survey... period unless it has been approved to undergo an underwater survey (UWILD) under § 169.230 of this part...

Underwater fiber-wireless communication with a passive front end

NASA Astrophysics Data System (ADS)

Xu, Jing; Sun, Bin; Lyu, Weichao; Kong, Meiwei; Sarwar, Rohail; Han, Jun; Zhang, Wei; Deng, Ning

2017-11-01

We propose and experimentally demonstrate a novel concept on underwater fiber-wireless (Fi-Wi) communication system with a fully passive wireless front end. A low-cost step-index (SI) plastic optical fiber (POF) together with a passive collimating lens at the front end composes the underwater Fi-Wi architecture. We have achieved a 1.71-Gb/s transmission at a mean BER of 4.97 × 10-3 (1.30 × 10-3 when using power loading) over a 50-m SI-POF and 2-m underwater wireless channel using orthogonal frequency division multiplexing (OFDM). Although the wireless part is very short, it actually plays a crucial role in practical underwater implementation, especially in deep sea. Compared with the wired solution (e.g. using a 52-m POF cable without the UWOC part), the proposed underwater Fi-Wi scheme can save optical wet-mate connectors that are sophisticated, very expensive and difficult to install in deep ocean. By combining high-capacity robust POF with the mobility and ubiquity of underwater wireless optical communication (UWOC), the proposed underwater Fi-Wi technology will find wide application in ocean exploration.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Qingtao; Li, Liyu; Nie, Zimin

We will show a new method to differentiate the vanadium transport from concentration gradient and that from electric field. Flow batteries with vanadium and iron redox couples as the electro-active species were employed to investigate the transport behavior of vanadium ions in the presence of electric field. It was shown that electric field accelerated the positive-to-negative and reduced the negative-to-positive vanadium ions transport in charge process and affected the vanadium ions transport in an opposite way in discharge process. In addition, a method was designed to differentiate the concentration gradient-driven vanadium ions diffusion and electric field-driven vanadium ions migration. Simplifiedmore » mathematical model was established to simulate the vanadium ions transport in real charge-discharge operation of flow battery. The concentration gradient diffusion coefficients and electric-migration coefficients of V2+, V3+, VO2+, and VO2+ across Nafion membrane were obtained by fitting the experimental data.« less

Electrostatic Charging of the Pathfinder Rover

NASA Technical Reports Server (NTRS)

Siebert, Mark W.; Kolecki, Joseph C.

1996-01-01

The Mars Pathfinder mission will send a lander and a rover to the martian surface. Because of the extremely dry conditions on Mars, electrostatic charging of the rover is expected to occur as it moves about. Charge accumulation may result in high electrical potentials and discharge through the martian atmosphere. Such discharge could interfere with the operation of electrical elements on the rover. A strategy was sought to mitigate this charge accumulation as a precautionary measure. Ground tests were performed to demonstrate charging in laboratory conditions simulating the surface conditions expected at Mars. Tests showed that a rover wheel, driven at typical rover speeds, will accumulate electrical charge and develop significant electrical potentials (average observed, 110 volts). Measurements were made of wheel electrical potential, and wheel capacitance. From these quantities, the amount of absolute charge was estimated. An engineering solution was developed and recommended to mitigate charge accumulation. That solution has been implemented on the actual rover.

Electrical Versus Optical: Comparing Methods for Detecting Terahertz Radiation Using Neon Lamps

NASA Astrophysics Data System (ADS)

Slocombe, L. L.; Lewis, R. A.

2018-05-01

Terahertz radiation impinging on a lit neon tube causes additional ionization of the encapsulated gas. As a result, the electrical current flowing between the electrodes increases and the glow discharge in the tube brightens. These dual phenomena suggest two distinct modes of terahertz sensing. The electrical mode simply involves measuring the electrical current. The optical mode involves monitoring the brightness of the weakly ionized plasma glow discharge. Here, we directly compare the two detection modes under identical experimental conditions. We measure 0.1-THz radiation modulated at frequencies in the range 0.1-10 kHz, for lamp currents in the range 1-10 mA. We find that electrical detection provides a superior signal-to-noise ratio while optical detection has a faster response. Either method serves as the basis of a compact, robust, and inexpensive room-temperature detector of terahertz radiation.

Electrical description of N2 capacitively coupled plasmas with the global model

NASA Astrophysics Data System (ADS)

Cao, Ming-Lu; Lu, Yi-Jia; Cheng, Jia; Ji, Lin-Hong; Engineering Design Team

2016-10-01

N2 discharges in a commercial capacitively coupled plasma reactor are modelled by a combination of an equivalent circuit and the global model, for a range of gas pressure at 1 4 Torr. The ohmic and inductive plasma bulk and the capacitive sheath are represented as LCR elements, with electrical characteristics determined by plasma parameters. The electron density and electron temperature are obtained from the global model in which a Maxwellian electron distribution is assumed. Voltages and currents are recorded by a VI probe installed after the match network. Using the measured voltage as an input, the current flowing through the discharge volume is calculated from the electrical model and shows excellent agreement with the measurements. The experimentally verified electrical model provides a simple and accurate description for the relationship between the external electrical parameters and the plasma properties, which can serve as a guideline for process window planning in industrial applications.

Strength of the phase change materials on loading with the products of electric explosion of conductors

NASA Astrophysics Data System (ADS)

Savenkov, Georgiy; Morozov, Viktor; Kats, Victor

2018-05-01

Results of the experimentation on the destruction of the phase change materials (beeswax and paraffin) by the electric explosion of conductors are presented. The process of the explosion of copper and nickel titanium wires in both pure PCM and its mixture with nonosized additives of cuprous oxide is analyzed. The effect of this additive on the process of the expansion of the electric-discharge plasma during the electric explosion of conductors and on the strength of composite materials is demonstrated. The piezoprobe-based method of measurement of the radial pressure during samples destruction is developed. The experiments made it possible to determine the dimensions of the melting channel formed inside the samples during the explosion and the subsequent expansion of the electric-discharge plasma. The experiments are performed on the generator of short-term high-voltage pulses capable to shape the voltage of (10-24) kV.

Electrochromic device using mercaptans and organothiolate compounds

DOEpatents

Lampert, C.M.; Ma, Y.P.; Doeff, M.M.; Visco, S.

1995-08-15

An electrochromic cell is disclosed which comprises an electrochromic layer and a composite ion counter electrode for transporting ions. The counter electrode further comprises a polymer electrolyte material and an organosulfur material in which, in its discharged state, the organosulfur material is further comprised of a mercaptan or an organothiolate. In one preferred embodiment, both the electrochromic electrode and the counter electrode are transparent either to visible light or to the entire electromagnetic spectrum in both charged and discharged states. An electrochromic device is disclosed which comprises one or more electrochromic electrodes encased in glass or plastic plates on the inner surface of each of which is formed a transparent electrically conductive film. Electrical contacts, which are in electrical contact with the conductive films, facilitate external electrical connection. 5 figs.

Sound production to electric discharge: sonic muscle evolution in progress in Synodontis spp. catfishes (Mochokidae).

PubMed

Boyle, Kelly S; Colleye, Orphal; Parmentier, Eric

2014-09-22

Elucidating the origins of complex biological structures has been one of the major challenges of evolutionary studies. Within vertebrates, the capacity to produce regular coordinated electric organ discharges (EODs) has evolved independently in different fish lineages. Intermediate stages, however, are not known. We show that, within a single catfish genus, some species are able to produce sounds, electric discharges or both signals (though not simultaneously). We highlight that both acoustic and electric communication result from actions of the same muscle. In parallel to their abilities, the studied species show different degrees of myofibril development in the sonic and electric muscle. The lowest myofibril density was observed in Synodontis nigriventris, which produced EODs but no swim bladder sounds, whereas the greatest myofibril density was observed in Synodontis grandiops, the species that produced the longest sound trains but did not emit EODs. Additionally, S. grandiops exhibited the lowest auditory thresholds. Swim bladder sounds were similar among species, while EODs were distinctive at the species level. We hypothesize that communication with conspecifics favoured the development of species-specific EOD signals and suggest an evolutionary explanation for the transition from a fast sonic muscle to electrocytes. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Dispersive FDTD analysis of induced electric field in human models due to electrostatic discharge.

PubMed

Hirata, Akimasa; Nagai, Toshihiro; Koyama, Teruyoshi; Hattori, Junya; Chan, Kwok Hung; Kavet, Robert

2012-07-07

Contact currents flow from/into a charged human body when touching a grounded conductive object. An electrostatic discharge (ESD) or spark may occur just before contact or upon release. The current may stimulate muscles and peripheral nerves. In order to clarify the difference in the induced electric field between different sized human models, the in-situ electric fields were computed in anatomically based models of adults and a child for a contact current in a human body following ESD. A dispersive finite-difference time-domain method was used, in which biological tissue is assumed to obey a four-pole Debye model. From our computational results, the first peak of the discharge current was almost identical across adult and child models. The decay of the induced current in the child was also faster due mainly to its smaller body capacitance compared to the adult models. The induced electric fields in the forefingers were comparable across different models. However, the electric field induced in the arm of the child model was found to be greater than that in the adult models primarily because of its smaller cross-sectional area. The tendency for greater doses in the child has also been reported for power frequency sinusoidal contact current exposures as reported by other investigators.

New model simulations of the global atmospheric electric circuit driven by thunderstorms and electrified shower clouds: The roles of lightning and sprites

NASA Astrophysics Data System (ADS)

Rycroft, Michael J.; Odzimek, Anna; Arnold, Neil F.; Füllekrug, Martin; Kułak, Andrzej; Neubert, Torsten

2007-12-01

Several processes acting below, in and above thunderstorms and in electrified shower clouds drive upward currents which close through the global atmospheric electric circuit. These are all simulated in a novel way using the software package PSpice. A moderate negative cloud-to-ground lightning discharge from the base of a thunderstorm increases the ionospheric potential above the thundercloud by 0.0013%. Assuming the ionosphere to be an equipotential surface, this discharge increases the current flowing in the global circuit and the fair-weather electric field also by 0.0013%. A moderate positive cloud-to-ground lightning discharge from the bottom of a thunderstorm decreases the ionospheric potential by 0.014%. Such a discharge may trigger a sprite, causing the ionospheric potential to decrease by ˜1V. The time scales for the recovery of the ionospheric potential are shown to be ˜250s, which is of the same order as the CR time constant for the global circuit. Knowing the global average rate of lightning discharges, it is found that negative cloud-to-ground discharges increase the ionospheric potential by only ˜4%, and that positive cloud-to-ground discharges reduce it by ˜3%. Thus, overall, lightning contributes only ˜1%—an almost insignificant proportion—to maintaining the high potential of the ionosphere. It is concluded that the net upward current to the ionosphere due to lightning is only ˜20A. Further, it is concluded that conduction and convection currents associated with “batteries” within thunderclouds and electrified shower clouds contribute essentially equally (˜500A each) to maintaining the ionospheric potential.